alpha-synuclein and Disease-Models--Animal

Multiple system atrophy (MSA) is a rare neurodegenerative disorder with unclear etiology, currently difficult and delayed diagnosis, and rapid progression, leading to disability and lethality within 6 to 9 years after symptom onset. The neuropathology of MSA classifies the disease in the group of a-synucleinopathies together with Parkinson's disease and other Lewy body disorders, but features specific oligodendroglial inclusions, which are pathognomonic for MSA. MSA has no efficient therapy to date. Development of experimental models is crucial to elucidate the disease mechanisms in progression and to provide a tool for preclinical screening of putative therapies for MSA. In vitro and in vivo models, based on selective neurotoxicity, a-synuclein oligodendroglial overexpression, and strain-specific propagation of a-synuclein fibrils, have been developed, reflecting various facets of MSA pathology. Over the years, the continuous exchange from bench to bedside and backward has been crucial for the advancing of MSA modelling, elucidating MSA pathogenic pathways, and understanding the existing translational gap to successful clinical trials in MSA. The review discusses specifically advantages and limitations of the PLP-a-syn mouse model of MSA, which recapitulates motor and non-motor features of the human disease with underlying striatonigral degeneration, degeneration of autonomic centers, and sensitized olivopontocerebellar system, strikingly mirroring human MSA pathology.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Multiple System Atrophy; Neuropathology; Oligodendroglia; Phenotype; Translational Research, Biomedical

Alpha-synucleinopathies, such as Parkinson's disease, dementia with Lewy bodies and multiple system atrophy, are characterized by aberrant accumulation of alpha-synuclein and synaptic dysfunction leading to motor and cognitive deficits. Animal models of alpha-synucleinopathy have greatly facilitated the mechanistic understanding of the disease and the development of therapeutics. Various transgenic, alpha-synuclein fibril-injected, and toxin-injected animal models of Parkinson's disease and multiple system atrophy that recapitulate the disease pathology have been developed and widely used. Recent advances in positron emission tomography have allowed the noninvasive visualization of molecular alterations, underpinning behavioral dysfunctions in the brains of animal models and the longitudinal monitoring of treatment effects. Imaging studies in these disease animal models have employed multi-tracer PET designs to reveal dopaminergic deficits together with other molecular alterations. This review focuses on the development of new positron emission tomography tracers and studies of alpha-synuclein, synaptic vesicle glycoprotein 2A neurotransmitter receptor deficits such as dopaminergic receptor, dopaminergic transporter, serotonergic receptor, vesicular monoamine transporter 2, hypometabolism, neuroinflammation, mitochondrial dysfunction and leucine rich repeat kinase 2 in animal models of Parkinson's disease. The outstanding challenges and emerging applications are outlined, such as investigating the gut-brain-axis by using positron emission tomography in animal models, and provide a future outlook.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Multiple System Atrophy; Parkinson Disease; Positron-Emission Tomography

A key pathological event occurring in Parkinson's disease (PD) is the transneuronal spreading of alpha-synuclein (α-syn). Other hallmarks of PD include neurodegeneration, glial activation, and immune cell infiltration in susceptible brain regions. Although preclinical models can mimic most of the key characteristics of PD, it is crucial to know the biological bases of individual differences between them when choosing one over another, to ensure proper interpretation of the results and to positively influence the outcome of the experiments.. This review provides an overview of current preclinical models actively used to study the interplay between α-syn pathology, neuroinflammation and immune response in PD but also to explore new potential preclinical models or emerging therapeutic strategies intended to fulfill the unmet medical needs in this disease. Lastly, this review also considers the current state of the ongoing clinical trials of new drugs designed to target these processes and delay the initiation or progression of the disease.. Anti-inflammatory and immunomodulatory agents have been demonstrated to be very promising candidates for reducing disease progression; however, more efforts are needed to reduce the enormous gap between these and dopaminergic drugs, which have dominated the therapeutic market for the last sixty years.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Immunity; Neuroinflammatory Diseases; Parkinson Disease

Development of neuroprotective therapeutics for Parkinson's disease (PD) is facing a lack of translation from pre-clinical to clinical trials. One strategy for improvement is to increase predictive validity of pre-clinical studies by using extensively characterized animal models with a comprehensive set of validated pharmacodynamic readouts. Mice over-expressing full-length, human, wild-type alpha-synuclein under the Thy-1 promoter (Thy1-aSyn line 61) reproduce key features of sporadic PD, such as progressive loss of striatal dopamine, alpha-synuclein pathology, deficits in motor and non-motor functions, and elevation of inflammatory markers. Extensive work with this model by multiple laboratories over the past decade further increased confidence in its robustness and validity, especially for analyzing pathomechanisms of alpha-synuclein pathology and down-stream pathways, and for pre-clinical drug testing. Interestingly, while postnatal transgene expression is widespread in central and peripheral neurons, the extent and progression of down-stream pathology differs between brain regions, thereby replicating the characteristic selective vulnerability of neurodegenerative diseases. In-depth characterization of these readouts in conjunction with behavioral deficits has led to more informative endpoints for pre-clinical trials. Each drug tested in Thy1-aSyn line 61 enhances knowledge on how molecular targets, pathology, and functional behavioral readouts are interconnected, thereby further optimizing the platform towards predictive validity for clinical trials. Here, we present the current state of the art using Thy1-aSyn line 61 for drug target discovery, validation, and pre-clinical testing.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Parkinson Disease

With a current lack of disease-modifying treatments, an initiative toward implementing a precision medicine approach for treating Parkinson's disease (PD) has emerged. However, challenges remain in how to define and apply precision medicine in PD. To accomplish the goal of optimally targeted and timed treatment for each patient, preclinical research in a diverse population of rodent models will continue to be an essential part of the translational path to identify novel biomarkers for patient diagnosis and subgrouping, understand PD disease mechanisms, identify new therapeutic targets, and screen therapeutics prior to clinical testing. This review highlights the most common rodent models of PD and discusses how these models can contribute to defining and implementing precision medicine for the treatment of PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Parkinson Disease; Precision Medicine; Rodentia

The critical role of alpha-synuclein in Parkinson's disease represents a pivotal discovery. Some progress has been made over recent years in identifying disease-modifying therapies for Parkinson's disease that target alpha-synuclein. However, these treatments have not yet shown clear efficacy in slowing the progression of this disease. Several explanations exist for this issue. The pathogenesis of Parkinson's disease is complex and not yet fully clarified and the heterogeneity of the disease, with diverse genetic susceptibility and risk factors and different clinical courses, adds further complexity. Thus, a deep understanding of alpha-synuclein physiological and pathophysiological functions is crucial. In this review, we first describe the cellular and animal models developed over recent years to study the physiological and pathological roles of this protein, including transgenic techniques, use of viral vectors and intracerebral injections of alpha-synuclein fibrils. We then provide evidence that these tools are crucial for modelling Parkinson's disease pathogenesis, causing protein misfolding and aggregation, synaptic dysfunction, brain plasticity impairment and cell-to-cell spreading of alpha-synuclein species. In particular, we focus on the possibility of dissecting the pre- and postsynaptic effects of alpha-synuclein in both physiological and pathological conditions. Finally, we show how vulnerability of specific neuronal cell types may facilitate systemic dysfunctions leading to multiple network alterations. These functional alterations underlie diverse motor and non-motor manifestations of Parkinson's disease that occur before overt neurodegeneration. However, we now understand that therapeutic targeting of alpha-synuclein in Parkinson's disease patients requires caution, since this protein exerts important physiological synaptic functions. Moreover, the interactions of alpha-synuclein with other molecules may induce synergistic detrimental effects. Thus, targeting only alpha-synuclein might not be enough. Combined therapies should be considered in the future.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Humans; Neurons; Parkinson Disease

Disease modeling in non-human subjects is an essential part of any clinical research. To gain proper understanding of the etiology and pathophysiology of any disease, experimental models are required to replicate the disease process. Due to the huge diversity in pathophysiology and prognosis in different diseases, animal modeling is customized and specific accordingly. As in other neurodegenerative diseases, Parkinson's disease is a progressive disorder coupled with varying forms of physical and mental disabilities. The pathological hallmarks of Parkinson's disease are associated with the accumulation of misfolded protein called α-synuclein as Lewy body, and degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc) area affecting the patient's motor activity. Extensive research has already been conducted regarding animal modeling of Parkinson's diseases. These include animal systems with induction of Parkinson's, either pharmacologically or via genetic manipulation. In this review, we will be summarizing and discussing some of the commonly employed Parkinson's disease animal model systems and their applications and limitations.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Lewy Bodies; Parkinson Disease; Pars Compacta; Substantia Nigra

The spreading of misfolded alpha-synuclein (α-syn) protein has been observed in animal models of Parkinson's disease (PD) and other α-synucleinopathies that mimic human PD pathologies. In animal models, the spreading of α-syn has been associated with motor dysfunction and neuronal death. However, variability in both susceptible brain regions and cellular populations limits our understanding of the consequences of α-syn spreading and the development of associated therapies. Here, we have reviewed the physiological and pathological functions of α-syn and summarized the susceptible brain regions and cell types identified from human postmortem studies and exogenous α-syn injection-based animal models. We have reviewed the methods for inducing α-syn aggregation, the specific hosts, the inoculation sites, the routes of propagation, and other experimental settings that may affect the spreading pattern of α-syn, as reported in current studies. Understanding the spread of α-syn to produce a consistent PD animal model is vital for future drug discovery.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Parkinson Disease; Synucleinopathies

Alpha-synuclein aggregates are the hallmark pathology of Parkinson's disease, which can propagate in a stereotypical pattern along the brain-body axis. Parkinson's disease patients not only display heterogeneous symptoms but also show variable patterns of alpha-synuclein pathology and affected neuronal systems during the disease course, complicating early and accurate diagnosis. Emerging data from post-mortem and imaging studies strongly suggest that disease heterogeneity could, at least in part, be explained by variable disease onset site, i.e. brain or body. This has led to the recently hypothesized formulation of two Parkinson's disease-subtypes, a body-first subtype where pathogenic alpha-synuclein arises in the body and spreads to the brain, and a brain-first subtype where pathogenic alpha-synuclein arises in the brain and spreads to the body. From a preclinical perspective, several animal models have been adapted or developed to reproduce Parkinson's disease-like pathology in the brain or periphery aiming to address the site of disease onset. Here, we review the current rodent and primate models that aim to reproduce Parkinson's disease pathology development and spreading in the brain and/or body and discuss the value and shortcomings of these models for the development of potential future applications in clinical trials and personalized medicine.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Parkinson Disease

Alpha-synuclein (α-synuclein) is a small, acidic protein containing 140 amino acids, highly expressed in the brain and primarily localized in the presynaptic terminals. It is found in high concentrations in Lewy Bodies, proteinaceous aggregates that constitute a typical histopathologic hallmark of Parkinson's disease. Altered environmental conditions, genetic mutations and post-translational changes can trigger abnormal aggregation processes with the increased frequency of oligomers, protofibrils, and fibrils formation that perturbs the neuronal homeostasis leading to cell death. Relevant to neuronal activity, a function of α-synuclein that has been extensively detailed is its regulatory actions in the trafficking of synaptic vesicles, including the processes of exocytosis, endocytosis and neurotransmitter release. Most recently, increasing attention has been paid to the possible role that α-synuclein plays at a postsynaptic level by interacting with selective subunits of the glutamate N-methyl-d-aspartate receptor, altering the corticostriatal plasticity of distinct neuronal populations.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Humans; Lewy Bodies; Models, Animal; Parkinson Disease

α-Synuclein (αSyn) plays a major role in the pathogenesis of Parkinson's disease (PD), which is the second most common neurodegenerative disease after Alzheimer's disease. The accumulation of αSyn is a pathological hallmark of PD, and mutations in the

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila melanogaster; Humans; Mutation; Parkinson Disease

The degeneration of nigral dopaminergic neurons is considered the hallmark of Parkinson's disease (PD), and it is triggered by different factors, including mitochondrial dysfunction, Lewy body accumulation, neuroinflammation, excitotoxicity and metal accumulation. Despite the extensive literature devoted to unravelling the signalling pathways involved in neuronal degeneration, little is known about the functional impairments occurring in these cells during illness progression. Of course, it is not possible to obtain direct information on the properties of the dopaminergic cells in patients. However, several data are available in the literature reporting changes in the function of these cells in PD animal models. In the present manuscript, we focus on dopaminergic neuron functional properties and summarize shared or peculiar features of neuronal dysfunction in different PD animal models at different stages of the disease in an attempt to design a picture of the functional modifications occurring in nigral dopaminergic neurons during disease progression preceding their eventual death.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Parkinson Disease; Substantia Nigra

Intracellular deposition of alpha-synuclein (α-syn) as Lewy bodies and Lewy neurites is a central event in the pathogenesis of Parkinson's disease (PD) and other α-synucleinopathies. Transgenic mouse models overexpressing human α-syn, are useful research tools in preclinical studies of pathogenetic mechanisms. Such mice develop α-syn inclusions as well as neurodegeneration with a topographical distribution that varies depending on the choice of promoter and which form of α-syn that is overexpressed. Moreover, they display motor symptoms and cognitive disturbances that to some extent resemble the human conditions.. One of the main motives for assessing behavior in these mouse models is to evaluate the potential of new treatment strategies, including their impact on motor and cognitive symptoms. However, due to a high within-group variability with respect to such features, the behavioral studies need to be applied with caution. In this review, we discuss how to make appropriate choices in the experimental design and which tests that are most suitable for the evaluation of PD-related symptoms in such studies.. We have evaluated published results on two selected transgenic mouse models overexpressing wild type (L61) and mutated (A30P) α-syn in the context of their validity and utility for different types of behavioral studies.. By applying appropriate behavioral tests, α-syn transgenic mouse models provide an appropriate experimental platform for studies of symptoms related to PD and other α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Mice; Mice, Transgenic; Parkinson Disease; Synucleinopathies

Accumulating evidence suggests that microglia and peripheral immune cells may play determinant roles in the pathogenesis of Parkinson's disease (PD). Consequently, there is a need to take advantage of immune-related models of PD to study the potential contribution of microglia and peripheral immune cells to the degeneration of the nigrostriatal system and help develop potential therapies for PD. In this review, we have summarised the main PD immune models. From a historical perspective, we highlight first the main features of intranigral injections of different pro-inflammogens, including lipopolysaccharide (LPS), thrombin, neuromelanin, etc. The use of adenoviral vectors to promote microglia-specific overexpression of different molecules in the ventral mesencephalon, including α-synuclein, IL-1β, and TNF, are also presented and briefly discussed. Finally, we summarise different models associated with peripheral inflammation whose contribution to the pathogenesis of neurodegenerative diseases is now an outstanding question. Illustrative examples included systemic LPS administration and dextran sulfate sodium-induced colitis in rodents.

Topics: alpha-Synuclein; Animals; Dextran Sulfate; Disease Models, Animal; Lipopolysaccharides; Microglia; Models, Animal; Parkinson Disease; Substantia Nigra; Thrombin

Parkinson's disease (PD) is the second major progressive neurodegenerative disease, which critically impacts patients' quality of life. Based on genetics, animal models of genetic defects created by gene editing technology have clear advantages in reflecting PD's pathogenesis and pathological characteristics and exploring potential therapeutic targets for PD. In this review, we summarized animal models of genetic defects in various pathogenesis of PD, including α-synuclein abnormal encoding, autophagy-lysosome system defects, ubiquitin protease system defects, and mitochondria-related dysfunction, and discuss their respective advantages, limitations, and application directions to provide a reference for the application of animal models of PD and research on anti-PD therapy.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Neurodegenerative Diseases; Parkinson Disease; Peptide Hydrolases; Quality of Life; Ubiquitin

Injections of pre-formed α-synuclein fibrils (PFFs) or overexpression of α-synuclein using AAV vectors are commonly used as models of Parkinson-like synucleinopathy in rats and mice. In the modified method reviewed here, the "SynFib" model, the PFFs and the AAV vector are administered together unilaterally into the substantia nigra. This approach combines the key features of these two models, i.e., the generation of toxic α-synuclein aggregates and Lewy body-like inclusions, in combination with the increased vulnerability caused by increased cellular levels of α-synuclein. The combined AAV/PFF delivery offers several advantages over the standard PFF model due to the enhanced and accelerated α-synuclein pathology and microglial response induced by the PFF seeds in the presence of an elevated α-synuclein level. Injection of the AAV/PFF mixture into the substantia nigra makes it possible to target a larger proportion of the nigral dopamine neurons and obtain a level of dopamine cell loss (>60%) needed to induce significant impairments in drug-induced and spontaneous motor tests. The SynFib model shares attractive features of the standard 6-OHDA lesion model: a single unilateral stereotaxic intervention; pathology and cell loss developing over a short time span; and the possibility to monitor the degenerative changes using tests of motor behavior.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Mice; Parkinson Disease; Rats; Substantia Nigra; Synucleinopathies

Neurogenesis is a key mechanism of brain development and plasticity, which is impaired in chronic neurodegeneration, including Parkinson's disease. The accumulation of aberrant α-synuclein is one of the features of PD. Being secreted, this protein produces a prominent neurotoxic effect, alters synaptic plasticity, deregulates intercellular communication, and supports the development of neuroinflammation, thereby providing propagation of pathological events leading to the establishment of a PD-specific phenotype. Multidirectional and ambiguous effects of α-synuclein on adult neurogenesis suggest that impaired neurogenesis should be considered as a target for the prevention of cell loss and restoration of neurological functions. Thus, stimulation of endogenous neurogenesis or cell-replacement therapy with stem cell-derived differentiated neurons raises new hopes for the development of effective and safe technologies for treating PD neurodegeneration. Given the rapid development of optogenetics, it is not surprising that this method has already been repeatedly tested in manipulating neurogenesis in vivo and in vitro via targeting stem or progenitor cells. However, niche astrocytes could also serve as promising candidates for controlling neuronal differentiation and improving the functional integration of newly formed neurons within the brain tissue. In this review, we mainly focus on current approaches to assess neurogenesis and prospects in the application of optogenetic protocols to restore the neurogenesis in Parkinson's disease.

Topics: alpha-Synuclein; Animals; Astrocytes; Brain; Cell Differentiation; Disease Models, Animal; Hippocampus; Humans; Neural Stem Cells; Neurogenesis; Neuronal Plasticity; Neurons; Optogenetics; Parkinson Disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive death of dopaminergic neurons in the substantia nigra and the formation of Lewy bodies (LBs). Mutations in PD-related genes lead to neuronal pathogenesis through various mechanisms, with known examples including SNCA/α-synuclein (PAKR1), Parkin (PARK2), PINK1 (PARK6), DJ-1 (PARK7), and LRRK2 (PARK8). Molecular chaperones/co-chaperones are proteins that aid the folding of other proteins into a functionally active conformation. It has been demonstrated that chaperones/co-chaperones interact with PD-related proteins and regulate their function in PD. HSP70, HSP90 and small heat shock proteins can prevent neurodegeneration by regulating α-syn misfolding, oligomerization and aggregation. The function of chaperones is regulated by co-chaperones such as HSP110, HSP40, HOP, CHIP, and BAG family proteins. Parkin, PINK1 and DJ-1 are PD-related proteins which are associated with mitochondrial function. Molecular chaperones regulate mitochondrial function and protein homeostasis by interacting with these PD-related proteins. This review discusses critical molecular chaperones/co-chaperones and PD-related proteins which contribute to the pathogenesis of PD, hoping to provide new molecular targets for therapeutic interventions to thwart the disease progression instead of only bringing symptomatic relief. Moreover, appreciating the critical role of chaperones in PD can also help us screen efficient biomarkers to identify PD at an early stage.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Molecular Chaperones; Parkinson Disease; Substantia Nigra; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is characterized by four pathognomonic hallmarks: (1) motor and non-motor deficits; (2) neuroinflammation and oxidative stress; (3) pathological aggregates of the α-synuclein (α-syn) protein; (4) neurodegeneration of the nigrostriatal system. Recent evidence sustains that the aggregation of pathological α-syn occurs in the early stages of the disease, becoming the first trigger of neuroinflammation and subsequent neurodegeneration. Thus, a therapeutic line aims at striking back α-synucleinopathy and neuroinflammation to impede neurodegeneration. Another therapeutic line is restoring the compromised dopaminergic system using neurotrophic factors, particularly the glial cell-derived neurotrophic factor (GDNF). Preclinical studies with GDNF have provided encouraging results but often lack evaluation of anti-α-syn and anti-inflammatory effects. In contrast, clinical trials have yielded imprecise results and have reported the emergence of severe side effects. Here, we analyze the discrepancy between preclinical and clinical outcomes, review the mechanisms of the aggregation of pathological α-syn, including neuroinflammation, and evaluate the neurorestorative properties of GDNF, emphasizing its anti-α-syn and anti-inflammatory effects in preclinical and clinical trials.

Topics: alpha-Synuclein; Animals; Clinical Trials as Topic; Disease Models, Animal; Drug Evaluation, Preclinical; Glial Cell Line-Derived Neurotrophic Factor; Humans; Neuroinflammatory Diseases; Parkinson Disease; Protein Aggregation, Pathological

Alpha-synucleinopathies comprise progressive neurodegenerative diseases, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). They all exhibit the same pathological hallmark, which is the formation of α-synuclein positive deposits in neuronal or glial cells. The aggregation of α-synuclein in the cell body of neurons, giving rise to the so-called Lewy bodies (LBs), is the major characteristic for PD and DLB, whereas the accumulation of α-synuclein in oligodendroglial cells, so-called glial cytoplasmic inclusions (GCIs), is the hallmark for MSA. The mechanisms involved in the intracytoplasmic inclusion formation in neuronal and oligodendroglial cells are not fully understood to date. A possible mechanism could be an impaired autophagic machinery that cannot cope with the high intracellular amount of α-synuclein. In fact, different studies showed that reduced autophagy is involved in α-synuclein aggregation. Furthermore, altered levels of different autophagy markers were reported in PD, DLB, and MSA brains. To date, the trigger point in disease initiation is not entirely clear; that is, whether autophagy dysfunction alone suffices to increase α-synuclein or whether α-synuclein is the pathogenic driver. In the current review, we discuss the involvement of defective autophagy machinery in the formation of α-synuclein aggregates, propagation of α-synuclein, and the resulting neurodegenerative processes in α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Humans; Neurons; Oligodendroglia; Synucleinopathies

Neuroinflammation has long been associated with central nervous system pathology in α-synucleinopathy disorders including Parkinson's disease and multiple system atrophy. In the past decade, research-focused efforts in preclinical and experimental models have rallied around this idea, and considerable effort has been made to delineate critical neuroinflammatory processes. In this article, we discuss challenges in preclinical research, notably the use of animal models to recapitulate and dissect disease phenotypes as well as the need for more sensitive, reliable radiotracers to detect on-target efficacy of immunomodulatory treatments in both human Parkinson's disease as well as preclinical models. © 2020 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Inflammation; Models, Theoretical; Multiple System Atrophy; Synucleinopathies

Parkinson disease (PD) is a progressive movement functionality disorder resulting in tremor and inability to execute voluntary functions combined with the preponderant non-motor disturbances encompassing constipation and gastrointestinal irritation. Despite continued research, the pathogenesis of PD is not yet clear. The available class of drugs for effective symptomatic management of PD includes a combination of levodopa and carbidopa. In recent past, the link between gut with PD has been explored. According to recent preclinical evidence, pathogens such as virus or bacterium may initiate entry into the gut via the nasal cavity that may aggravate lewy pathology in the gut that eventually propagates and progresses towards the brain via the vagus nerve resulting in the prodromal non-motor symptoms. Additionally, experimental evidence also suggests that alpha-synuclein misfolding commences at a very early stage in the gut and is transported via the vagus nerve prior to seeding PD pathology in the brain. However, this progression and resultant deterioration of the neurones can effectively be altered by an autophagy inducer, Trehalose, although the mechanism behind it is still enigmatic. Hence, this review will mainly focus on analysing the basic components of the gut that might be responsible for aggravating lewy pathology, the mediator(s) responsible for transmission of PD pathology from gut to brain and the important role of trehalose in ameliorating gut dysbiosis related PD complications that would eventually pave the way for therapeutic management of PD.

Topics: alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Dysbiosis; Gastrointestinal Microbiome; Humans; Intestinal Mucosa; Parkinson Disease; Protein Aggregates; Trehalose

With the world's population ageing, the incidence of Parkinson's disease (PD) is on the rise. In recent years, inflammatory processes have emerged as prominent contributors to the pathology of PD. There is great evidence that microglia have a significant neuroprotective role, and that impaired and over activated microglial phenotypes are present in brains of PD patients. Thereby, PD progression is potentially driven by a vicious cycle between dying neurons and microglia through the instigation of oxidative stress, mitophagy and autophagy dysfunctions, a-synuclein accumulation, and pro-inflammatory cytokine release. Hence, investigating the involvement of microglia is of great importance for future research and treatment of PD. The purpose of this review is to highlight recent findings concerning the microglia-neuronal interplay in PD with a focus on human postmortem immunohistochemistry and single-cell studies, their relation to animal and iPSC-derived models, newly emerging technologies, and the resulting potential of new anti-inflammatory therapies for PD.

Topics: alpha-Synuclein; Animals; Brain; Cytokines; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Inflammation; Microglia; Nerve Degeneration; Neuroimmunomodulation; Neurons; Neuroprotection; Oxidative Stress; Parkinson Disease

Multiple system atrophy (MSA) is a rare, severe, and rapidly progressive neurodegenerative disorder categorized as an atypical parkinsonian syndrome. With a mean life expectancy of 6-9 years after diagnosis, MSA is clinically characterized by parkinsonism, cerebellar ataxia, autonomic failure, and poor l-Dopa responsiveness. Aside from limited symptomatic treatment, there is currently no disease-modifying therapy available. Consequently, distinct pharmacological targets have been explored and investigated in clinical studies based on MSA-related symptoms and pathomechanisms. Parkinsonism, cerebellar ataxia, and autonomic failure are the most important symptoms targeted by symptomatic treatments in current clinical trials. The most prominent pathological hallmark is oligodendroglial cytoplasmic inclusions containing alpha-synuclein, thus classifying MSA as synucleinopathy. Additionally, myelin and neuronal loss accompanied by micro- and astrogliosis are further distinctive features of MSA-related neuropathology present in numerous brain regions. Besides summarizing current symptomatic treatment strategies in MSA, this review critically reflects upon potential cellular targets and disease-modifying approaches for MSA such as (I) targeting α-syn pathology, (II) intervening neuroinflammation, and (III) neuronal loss. Although these single compound trials are aiming to interfere with distinct pathogenetic steps in MSA, a combined approach may be necessary to slow down the rapid progression of the oligodendroglial associated synucleinopathy.

Topics: Adrenergic alpha-1 Receptor Agonists; alpha-Synuclein; Animals; Disease Models, Animal; Humans; Induced Pluripotent Stem Cells; Monoamine Oxidase Inhibitors; Multiple System Atrophy; Neuroglia; Peroxidase

Prion-like propagation has been proposed to underlie the pathogenesis and progression of many progressive neurodegenerative diseases, and considerable experimental evidence has been accumulated to support this idea. However, only limited evidence is available from the brains of patients, and it is not clear how well various experimental models reflect the clinical situation. In this review, I discuss experimental models of prion-like propagation, focusing on three major disease-associated intracellular proteins, α-synuclein, tau and transactivation response DNA-binding protein 43 kDa, which provide a molecular basis for evaluating the spread of pathologies in diseased brains, known as Braak staging. Although some issues remain, and further biochemical and structural analyses are needed, it seems clear that the concept of prion-like propagation is the key to understanding disease progression, as well as for the development of disease-modifying therapies.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Disease Progression; DNA-Binding Proteins; Humans; Models, Neurological; Neurodegenerative Diseases; Prion Diseases; Protein Aggregation, Pathological; tau Proteins

Parkinson's disease (PD) is a disease of the human nervous system with an onset, in the sixth and seventh decades of the human life. Chiefly perceived as progressive degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) with the ensued loss of dopamine in the striatum and the presence of Lewy bodies, consisting of α-synuclein agglomeration. In which the neuronal bridge between substantia nigra and striatum plays an advent role in the motor system. Dilapidation of these neurons results in dopamine depletion which in-turn makes hay to PD. Eventually, the etiology and pathogenesis of PD were still on a hike of dilemma. Traditional Chinese medicine (TCM), including Chinese herbal remedies, acupuncture, and manipulative therapies, is commonly used as an adjunctive therapy in different diseases, particularly neurological diseases, in Asian countries. Additionally, TCM might improve the prognoses and the quality of life of patients with PD because it induces less adverse drug reactions. The present review describes research on the various neuroprotective components and herbal extracts from herbal medicines in the context of addressing the effects of PD.

Topics: alpha-Synuclein; Animals; Brain; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Medicine, Chinese Traditional; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinson Disease; Pars Compacta; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a progressive neurodegenerative disease due to the degeneration of dopaminergic neurons in substantia nigra pars compacta of the mid brain. The present study investigates the neuro-protective role of synthesized ropinirole silver nanocomposite (RPAgNC) in Drosophila model of PD. α-synuclein accumulation in the brain of flies (PD flies) leads to the damage of dopaminergic neurons, dopamine depletion, impaired muscular coordination, memory decline and increase in oxidative stress. Ingestion of the RPAgNC by Drosophila significantly prevented the neuronal degeneration compared to only ropinirole. The results confirm that the RPAgNC exerts more neuro-protective effect compared to dopamine agonist i.e. ropinirole as such drug in experimental PD flies. This article is part of the special issue entitled 'The Quest for Disease-Modifying Therapies for Neurodegenerative Disorders'.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Disease Models, Animal; Drosophila melanogaster; Humans; Indoles; Male; Nanocomposites; Neurodegenerative Diseases; Parkinsonian Disorders; Silver

We hypothesize that Parkinson's disease (PD) pathogenesis can be divided into three temporal phases. During the first phase, 'triggers', such as viral infections or environmental toxins, spark the disease process in the brain and/or peripheral tissues. Triggers alone, however, may be insufficient, requiring 'facilitators' like peripheral inflammation for PD pathology to develop. Once the disease manifests, 'aggravators' spur further neurodegeneration and exacerbate symptoms. Aggravators are proposed to include impaired autophagy and cell-to-cell propagation of α-synuclein pathology. We believe clinical trials need to consider these three phases and target potential therapies at the appropriate stage of the disease process in order to be effective.

Topics: alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Humans; Neurons; Parkinson Disease

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by selective and progressive loss of dopaminergic neurons. Genetic and environmental risk factors are associated with this disease. The genetic factors are composed of approximately 20 genes, such as SNCA, parkin, PTEN-induced kinase1 (pink1), leucine-rich repeat kinase 2 (LRRK2), ATP13A2, MAPT, VPS35, and DJ-1, whereas the environmental factors consist of oxidative stress-induced toxins such as 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP), rotenone, and paraquat. The analyses of their functions and mechanisms have provided important insights into the disease process, which has demonstrated that these factors cause oxidative damage and mitochondrial dysfunction. The most invaluable studies have been performed using disease model organisms, such as mice, fruit flies, and worms. Among them, Drosophila melanogaster has emerged as an excellent model organism to study both environmental and genetic factors and provide insights to the pathways relevant for PD pathogenesis, facilitating development of therapeutic strategies. In this review, we have focused on the fly model organism to summarize recent progress, including pathogenesis, neuroprotective compounds, and newer approaches. [BMB Reports 2019; 52(4): 250-258].

Topics: Adenosine Triphosphatases; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Drosophila melanogaster; Drosophila Proteins; Hazardous Substances; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Membrane Proteins; Mitochondria; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Protein Deglycase DJ-1; Protein Serine-Threonine Kinases; Ubiquitin-Protein Ligases; Vesicular Transport Proteins

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. PD is characterized by the loss of dopaminergic neurons, primarily in brain regions that control motor functions, thereby leading to motor impairments in the patients. Pathological aggregated forms of the synaptic protein, α-synuclein (α-syn), are involved in the generation and progression of PD. In PD brains, α-syn accumulates inside neurons and propagates from cell-to-cell in a prion-like manner. In this review, we discuss the in vitro and in vivo models used to study the prion-like properties of α-syn and related findings. In particular, we focus on the different mechanisms of α-syn spreading, which could be relevant for the development of alternative therapeutic approaches for PD treatment.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Parkinson Disease; Prions

Despite decades of research, accurate diagnosis of Parkinson's disease remains a challenge, and disease-modifying treatments are still lacking. Research into the early (presymptomatic) stages of Parkinson's disease and the discovery of novel biomarkers is of utmost importance to reduce this burden and to come to a more accurate diagnosis at the very onset of the disease. Many have speculated that non-motor symptoms could provide a breakthrough in the quest for early biomarkers of Parkinson's disease, including the visual disturbances and retinal abnormalities that are seen in the majority of Parkinson's disease patients. An expanding number of clinical studies have investigated the use of in vivo assessments of retinal structure, electrophysiological function, and vision-driven tasks as novel means for identifying patients at risk that need further neurological examination and for longitudinal follow-up of disease progression in Parkinson's disease patients. Often, the results of these studies have been interpreted in relation to α-synuclein deposits and dopamine deficiency in the retina, mirroring the defining pathological features of Parkinson's disease in the brain. To better understand the visual defects seen in Parkinson's disease patients and to propel the use of retinal changes as biomarkers for Parkinson's disease, however, more conclusive neuropathological evidence for the presence of retinal α-synuclein aggregates, and its relation to the cerebral α-synuclein burden, is urgently needed. This review provides a comprehensive and critical overview of the research conducted to unveil α-synuclein aggregates in the retina of Parkinson's disease patients and animal models, and thereby aims to aid the ongoing discussion about the potential use of the retinal changes and/or visual symptoms as biomarkers for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Parkinson Disease; Retina

Protein misfolding and overloaded proteostasis networks underlie a range of neurodegenerative diseases. No cures exist for these diseases, but developing effective therapeutic agents targeting the toxic, misfolded protein species in disease is one promising strategy. AAA+ (ATPases associated with diverse cellular activities) protein translocases, which naturally unfold and translocate substrate proteins, could be potent therapeutic agents to disassemble toxic protein conformers in neurodegenerative disease. Here, we discuss repurposing AAA+ protein translocases Hsp104 and proteasome-activating nucleotidase (PAN) to alleviate the toxicity from protein misfolding in neurodegenerative disease. Hsp104 effectively protects various animal models from neurodegeneration underpinned by protein misfolding, and enhanced Hsp104 variants strongly counter neurodegenerative disease-associated protein misfolding toxicity in yeast, Caenorhabditis elegans, and mammalian cells. Similarly, a recently engineered PAN variant (PAN

Topics: Adenosine Triphosphatases; alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Heat-Shock Proteins; Humans; Neurodegenerative Diseases; Protein Conformation; Protein Folding; Protein Transport; Saccharomyces cerevisiae

Ordered assemblies of proteins are found in the postmortem brains of sufferers of several neurodegenerative diseases. The cytoplasmic microtubule associated protein tau and alpha-synuclein (αS) are found in an assembled state in Alzheimer's disease and Parkinson's disease, respectively. An accumulating body of evidence suggests a "prion-like" mechanism of spread of these assemblies through the diseased brain. Under this hypothesis, assembled variants of these proteins promote the conversion of native proteins to the assembled state. This likely inflicts pathology on cells of the brain through a toxic gain-of-function mechanism. Experiments in animal models of tau and αS pathology have demonstrated that the passive transfer of anti-tau or anti-αS antibodies induces a reduction in the levels of assembled proteins. This is further accompanied by improvements in neurological function and preservation of brain volume. Immunotherapy is therefore considered one of the brightest hopes as a therapeutic avenue in an area currently without disease-modifying therapy. Following a series of disappointing clinical trials targeting beta-amyloid, a peptide that accumulates in the extracellular spaces of the AD brain, attention is turning to active and passive immunotherapies that target tau and αS. However, there are several remaining uncertainties concerning the mechanism by which antibodies afford protection against self-propagating protein conformations. This review will discuss current understanding of how antibodies and their receptors can be brought to bear on proteins involved in neurodegeneration. Parallels will be made to antibody-mediated protection against classical viral infections. Common mechanisms that may contribute to protection against self-propagating protein conformations include blocking the entry of protein "seeds" to cells, clearance of immune complexes by microglia, and the intracellular protein degradation pathway initiated by cytoplasmic antibodies via the Fc receptor TRIM21. As with anti-viral immunity, protective mechanisms may be accompanied by the activation of immune signaling pathways and we will discuss the suitability of such activation in the neurological setting.

Topics: alpha-Synuclein; Animals; Autoantibodies; Brain; Disease Models, Animal; Humans; Immunotherapy; Neurodegenerative Diseases; tau Proteins; Vaccines

Parkinson's disease (PD) is a progressive neurological disorder associated with the loss of dopaminergic neurons (DNs) in the substantia nigra and the widespread accumulation of α-synuclein (α-syn) protein, leading to motor impairments and eventual cognitive dysfunction. In-vitro cell cultures and in-vivo animal models have provided the opportunity to investigate the PD pathological hallmarks and identify different therapeutic compounds. However, PD pathogenesis and causes are still not well understood, and effective inhibitory drugs for PD are yet to be discovered. Biologically simple but pathologically relevant disease models and advanced screening technologies are needed to reveal the mechanisms underpinning protein aggregation and PD progression. For instance, Caenorhabditis elegans (C. elegans) offers many advantages for fundamental PD neurobehavioral studies including a simple, well-mapped, and accessible neuronal system, genetic homology to humans, body transparency and amenability to genetic manipulation. Several transgenic worm strains that exhibit multiple PD-related phenotypes have been developed to perform neuronal and behavioral assays and drug screening. However, in conventional worm-based assays, the commonly used techniques are equipment-intensive, slow and low in throughput. Over the past two decades, microfluidics technology has contributed significantly to automation and control of C. elegans assays. In this review, we focus on C. elegans PD models and the recent advancements in microfluidic platforms used for manipulation, handling and neurobehavioral screening of these models. Moreover, we highlight the potential of C. elegans to elucidate the in-vivo mechanisms of neuron-to-neuron protein transfer that may underlie spreading Lewy pathology in PD, and its suitability for in-vitro studies. Given the advantages of C. elegans and microfluidics technology, their integration has the potential to facilitate the investigation of disease pathology and discovery of potential chemical leads for PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Culture Techniques; Cognitive Dysfunction; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Drug Evaluation, Preclinical; Equipment Design; Genotype; Humans; Lab-On-A-Chip Devices; Materials Testing; Microfluidics; Parkinson Disease; Phenotype; Substantia Nigra

The protein α-synuclein has a central role in the pathogenesis of Parkinson's disease (PD). In this review, we discuss recent results concerning its primary function, which appears to be on cell membranes. The pre-synaptic location of synuclein has suggested a role in neurotransmitter release and it apparently associates with synaptic vesicles because of their high curvature. Indeed, synuclein over-expression inhibits synaptic vesicle exocytosis. However, loss of synuclein has not yet been shown to have a major effect on synaptic transmission. Consistent with work showing that synuclein can promote as well as sense membrane curvature, recent analysis of synuclein triple knockout mice now shows that synuclein accelerates dilation of the exocytic fusion pore. This form of regulation affects primarily the release of slowly discharged lumenal cargo such as neural peptides, but presumably also contributes to maintenance of the release site. This article is part of the Special Issue "Synuclein".

Topics: alpha-Synuclein; Animals; Axons; Cell Membrane; Disease Models, Animal; Dopamine; Exocytosis; Humans; Membrane Fusion; Mice, Knockout; Mice, Transgenic; Mitochondria; Mutation, Missense; Parkinson Disease; Presynaptic Terminals; Protein Domains; Protein Folding; Protein Isoforms; Recombinant Proteins; Secretory Vesicles; Synaptic Vesicles

Homozygous and heterozygous mutations in GBA1, the gene implicated in Gaucher disease, increase the risk and severity of Parkinson disease (PD). We evaluated the design, phenotype, strengths, and limitations of current GBA1-associated PD mouse models. Although faithful modeling of a genetic risk factor poses many challenges, the different approaches taken were successful in revealing predisposing abnormalities in heterozygotes for GBA1 mutations and demonstrating the deleterious effects of GBA1 impairment on the PD course in PD models. GBA1-PD models differ in key parameters, with no single model recapitulating all aspects of the GBA1-PD puzzle, emphasizing the importance of selecting the proper in vivo model depending on the specific molecular mechanism or potential therapy being studied.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Gaucher Disease; Glucosylceramidase; Humans; Mutation; Parkinson Disease

Research with animal models has led to critical health advances that have saved or improved the lives of millions of human beings. Specifically, nonhuman primate's genetic and anatomo-physiological similarities to humans are especially important for understanding processes like Parkinson's disease, which only occur in humans. Unambiguously, the unique contribution made by nonhuman primate research to our understanding of Parkinson's disease is widely recognized. For example, monkeys with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) parkinsonisms are responsive to dopamine replacement therapies, mimicking what is seen in PD patients. Moreover, groundbreaking neuroanatomical and electrophysiological studies using this monkey model in the 1980s and 1990s enabled researchers to identify the neuronal circuits responsible for the cardinal motor features of PD. This led to the development of subthalamic surgical ablation and deep brain stimulation, the current therapeutic gold standard for neurosurgical treatment. More recently, the mechanisms of α-synuclein spreading testing the prion hypothesis for PD have yielded exciting results. In this review, we discuss and highlight how the findings from nonhuman primate research contribute to our understanding of idiopathic Parkinson's disease.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Parkinson Disease; Parkinson Disease, Secondary

Proper understanding of the mechanism(s) by which α-synuclein misfolds and propagates may hold the key to unraveling the complex pathophysiology of Parkinson's disease. A more complete understanding of the disease itself, as well as establishing animal models that fully recapitulate pathological and functional disease progression, are needed to develop treatments that will delay, halt or reverse the disease course. Traditional neurotoxin-based animal models fail to mimic crucial aspects of Parkinson's and thus are not relevant for the study of neuroprotection and disease-modifying therapies. Therefore, a new era of animal models centered on α-synuclein has emerged with the utility of nonhuman primates in these studies beginning to become important. Indeed, disease modeling in nonhuman primates offers a more similar anatomical and genetic background to humans, and the ability to assess complex behavioral impairments that are difficult to test in rodents. Furthermore, results obtained from monkey studies translate better to applications in humans. In this review, we highlight the importance of α-synuclein in Parkinson's disease and discuss the development of α-synuclein based nonhuman primate models.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Parkinson Disease; Primates

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder with a highly variable clinical presentation. Unfortunately, there exists no effective therapy that can improve the course of the disease and symptomatic treatment options remain limited. Although significant progress in research has improved our understanding of MSA, knowledge gaps still remain. Thus, a global network focusing on different research areas is required to face this fatal disease.

Topics: alpha-Synuclein; Animals; Biomarkers; Clinical Trials as Topic; Disease Models, Animal; Humans; Multiple System Atrophy; Translational Research, Biomedical

Over the last decade a prominent amount of studies in preclinical transgenic models of multiple system atrophy (MSA) has been performed. These studies have helped understand mechanisms downstream to the α-synuclein oligodendroglial accumulation relevant to human MSA. However, the successful translation of the preclinical outcomes into a clinical trial has failed. Looking back, we can now identify possible confounders for the failure. Biomarkers of disease progression are mostly missing. Early diagnosis and initiation of therapeutic clinical trials is limited. The need of both proof-of-concept as well as clinically relevant preclinical study designs with clinically relevant timing and preclinical readouts is identified as a must in our translational efforts for MSA to date. Finally, improved clinical study designs with improved enrollment criteria, and measurement outcomes are warranted on the way to finding the successful therapeutic approach for MSA. This review provides an overview of experimental studies and clinical trials for MSA and the lessons learned over the last decade towards the identification of the cure for MSA.

Topics: alpha-Synuclein; Animals; Clinical Trials as Topic; Disease Models, Animal; Disease Progression; Humans; Multiple System Atrophy; Translational Research, Biomedical

Multiple system atrophy (MSA) is a fatal neurodegenerative disorder characterized by the abnormal accumulation of toxic forms of the synaptic protein alpha-synuclein (α-syn) within oligodendrocytes and neurons. The presence of α-syn within oligodendrocytes in the form of glial cytoplasmic inclusions is the diagnostic hallmark of MSA. However, it has been postulated that α-syn is produced in neurons and propagates to oligodendrocytes, where unknown mechanisms lead to its accumulation. The presence of α-syn within neurons in MSA has not been so extensively studied, but it may shed light into neuropathological mechanisms leading to oligodendroglial accumulation. Here we summarize the principal neuropathological events of MSA, and discuss how a deeper knowledge of these mechanisms may help develop effective therapies targeting α-syn accumulation and spreading.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Multiple System Atrophy; Neurons; Neuropathology; Oligodendroglia

The abnormal accumulation of α-synuclein aggregates in neurons, nerve fibers, or glial cells is the hallmark of a group of neurodegenerative diseases known collectively as α-synucleinopathies. Clinical, neuropathological, and experimental evidence strongly suggests that α-synuclein plays a role not only as a trigger of pathological processes at disease inception, but also as a mediator of pathological spreading during disease progression. Specific properties of α-synuclein, such as its ability to pass from one neuron to another, its tendency to aggregate, and its potential to generate self-propagating species, have been described and elucidated in animal models and may contribute to the relentless exacerbation of Parkinson's disease pathology in patients. Animal models used for studying α-synuclein accumulation, aggregation, and propagation are mostly based on three approaches: (1) intra-parenchymal inoculations of exogenous α-synuclein (e.g., synthetic α-synuclein fibrils), (2) transgenic mice, and (3) animals (mice or rats) in which α-synuclein overexpression is induced by viral vector injections. Whereas pathological α-synuclein changes are consistently observed in these models, important differences are also found. In particular, pronounced pathology in transgenic mice and viral vector-injected animals does not appear to involve self-propagating α-synuclein species. A critical discussion of these models reveals their strengths and limitations and provides the basis for recommendations concerning their use for future investigations.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Genetic Vectors; Humans

Olfactory limbic structures, like the amygdala, the entorhinal, and the piriform cortices, are closely involved in cognitive processes. Thus, besides olfactory dysfunctions, it is conceivable that the compromise of these structures can lead to cognitive impairment. The olfactory bulb is affected by alpha-synuclein pathology in almost all cases of both Parkinson's disease and dementia with Lewy bodies. The clinical distinction between these disorders relies on the timing in the appearance of dementia in relationship to motor symptoms. Typically, it occurs late in the course of Parkinson's disease, and within the first year in dementia with Lewy bodies. The close anatomical proximity of the olfactory bulb with limbic regions, together with the early occurrence of cognitive impairment that is observed in dementia with Lewy bodies, raise the question whether the propagation of alpha-synuclein pathology in this condition might originate in the olfactory bulb, spreading from there to other limbic structures, and thereby reaching the associative neocortex. This review will describe the anatomical basis of the olfactory system and discuss the evidence of potential spreading pathways from the olfactory bulb that could support the presence of early dementia in the setting of Lewy body disorders.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Body Disease; Models, Biological; Olfactory Bulb

Preclinical research on Parkinson's disease has relied heavily on mouse and rat animal models. Initially, PD animal models were generated primarily by chemical neurotoxins that induce acute loss of dopaminergic neurons in the substantia nigra. On the discovery of genetic mutations causally linked to PD, mice were used more than rats to generate laboratory animals bearing PD-linked mutations because mutagenesis was more difficult in rats. Recent advances in technology for mammalian genome engineering and optimization of viral expression vectors have increased the use of genetic rat models of PD. Emerging research tools include "knockout" rats with disruption of genes in which mutations have been causally linked to PD, including LRRK2, α-synuclein, Parkin, PINK1, and DJ-1. Rats have also been increasingly used for transgenic and viral-mediated overexpression of genes relevant to PD, particularly α-synuclein. It may not be realistic to obtain a single animal model that completely reproduces every feature of a human disease as complex as PD. Nevertheless, compared with mice with the same mutations, many genetic rat animal models of PD better reproduce key aspects of PD including progressive loss of dopaminergic neurons in the substantia nigra, locomotor behavior deficits, and age-dependent formation of abnormal α-synuclein protein aggregates. Here we briefly review new developments in genetic rat models of PD that may have greater potential for identifying underlying mechanisms, for discovering novel therapeutic targets, and for developing greatly needed treatments to slow or halt disease progression. © 2018 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Parkinson Disease; Protein Kinases; Rats; Rats, Transgenic; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is an adult onset neurodegenerative disease that is characterized by selective degeneration of neurons primarily in the substantia nigra. At present, the pathogenesis of PD is incompletely understood and there are no neuroprotective treatments available. Accurate animal models of PD provide the opportunity to elucidate disease mechanisms and identify therapeutic targets. This review focuses on C. elegans models of PD, including both genetic and toxicant models. This microscopic worm offers several advantages for the study of PD including ease of genetic manipulation, ability to complete experiments rapidly, low cost, and ability to perform large scale screens for disease modifiers. A number of C. elegans models of PD have been generated including transgenic worms that express α-synuclein or LRRK2, and worms with deletions in PRKN/pdr-1, PINK1/pink-1, DJ-1/djr-1.1/djr-1.2 and ATP13A2/catp-6. These worms have been shown to exhibit multiple phenotypic deficits including the loss of dopamine neurons, disruption of dopamine-dependent behaviors, increased sensitivity to stress, age-dependent aggregation, and deficits in movement. As a result, these phenotypes can be used as outcome measures to gain insight into disease pathogenesis and to identify disease modifiers. In this way, C. elegans can be used as an experimental tool to elucidate mechanisms involved in PD and to find novel therapeutic targets that can subsequently be validated in other models.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopaminergic Neurons; Drug Evaluation, Preclinical; Feeding Behavior; Gene-Environment Interaction; Genes, Reporter; Humans; Mitochondria; Movement Disorders; Nerve Degeneration; Neurotoxins; Parkinsonian Disorders; Phenotype; Protein Aggregation, Pathological; Recombinant Fusion Proteins; RNA Interference; Species Specificity

Apart from the characteristic and progressive motor- and movement-related problems, Parkinson's disease (PD) patients also suffer from several non-motor symptoms, including gastrointestinal dysfunction. The fact that the enteric nervous system (ENS) controls motility and that one of the typical PD hallmarks, α-synuclein-positive deposits, has also been found in the intestinal wall have rendered the ENS and the gut a popular subject of study in the context of PD. The possibility that these deposits could serve as an early biomarker is obviously of tremendous medical benefit but also the idea that the gut may possibly be a gateway via which the disease is initiated and progressively makes its way via the peripheral nerves to the central nervous system has increased the interest in the ENS-PD link. Furthermore, the fact that gastrointestinal symptoms are present in PD suggests that the ENS might be affected as well. However, despite a large body of literature on the topic, the actual role or the magnitude of involvement of the ENS in PD remains elusive. The multitudes of experimental approaches and animal models have complicated the interpretation of results and the outcome of different studies does not necessarily align well. In this review, we chose to highlight some elements of interest and some items of confusion, particularly those where research should be focusing. We also list a number of open questions in the field that could serve as a guideline for future, preferably concerted research.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Enteric Nervous System; Gastrointestinal Diseases; Humans; Parkinson Disease; Protein Aggregates

The role of autoimmunity in Parkinson's disease (PD), as one of the most popular research subjects, has been intensively investigated in recent years. Although the ultimate cause of PD is unknown, one major area of interest remains identifying new therapeutic targets and options for patients suffering from PD. Herein, we present a comprehensive review of the impacts of autoimmunity in neurodegenerative diseases, especially PD, and we have composed a logical argument to substantiate that autoimmunity is actively involved in the pathogenesis of PD through several proteins, including α-synuclein, DJ-1, PINK1, and Parkin, as well as immune cells, such as dendritic cells, microglia, T cells, and B cells. Furthermore, a detailed analysis of the relevance of autoimmunity to the clinical symptoms of PD provides strong evidence for the close correlation of autoimmunity with PD. In addition, the previously identified relationships between other autoimmune diseases and PD help us to better understand the disease pattern, laying the foundation for new therapeutic solutions to PD. In summary, this review aims to integrate and present currently available data to clarify the pathogenesis of PD and discuss some controversial but innovative research perspectives on the involvement of autoimmunity in PD, as well as possible novel diagnostic methods and treatments based on autoimmunity targets.

Topics: alpha-Synuclein; Animals; Autoantigens; Autoimmunity; B-Lymphocytes; Brain; Dendritic Cells; Disease Models, Animal; Humans; Microglia; Mutation; Parkinson Disease; Protein Deglycase DJ-1; Protein Kinases; T-Lymphocytes; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is a neurodegenerative disorder resulting from degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). PD is characterized by motor dysfunctions as well as gastrointestinal symptoms and mental impairment. The pathological hallmark of PD is an accumulation of misfolded α-synuclein aggregates within the brain. The etiology of PD and related synucleinopathy is poorly understood, but recently, the hypothesis that α-synuclein pathology spreads in a prion-like fashion originating in the gut has gained much scientific attention. A crucial clue was the appearance of constipation before the onset of motor symptoms, gut dysbiosis and synucleinopathy in PD patients. Another line of evidence, demonstrating accumulation of α-synuclein within the peripheral autonomic nervous system (PANS), including the enteric nervous system (ENS), and the dorsal motor nucleus of the vagus (DMV) support the concept that α-synuclein can spread from the ENS to the brain by the vagus nerve. The decreased risk of PD following truncal vagotomy supports this. The convincing evidence of the prion-like behavior of α-synuclein came from postmortem observations that pathological α-synuclein inclusions appeared in healthy grafted neurons. In this review, we summarize the available data from human subjects' research and animal experiments, which seem to be the most suggestive for explaining the hypotheses.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Gastrointestinal Diseases; Humans; Parkinson Disease; Prion Diseases

The field of gene therapy has recently witnessed a number of major conceptual changes. Besides the traditional thinking that comprises the use of viral vectors for the delivery of a given therapeutic gene, a number of original approaches have been recently envisaged, focused on using vectors carrying genes to further modify basal ganglia circuits of interest. It is expected that these approaches will ultimately induce a therapeutic potential being sustained by gene-induced changes in brain circuits. Among others, at present, it is technically feasible to use viral vectors to (1) achieve a controlled release of neurotrophic factors, (2) conduct either a transient or permanent silencing of any given basal ganglia circuit of interest, (3) perform an in vivo cellular reprogramming by promoting the conversion of resident cells into dopaminergic-like neurons, and (4) improving levodopa efficacy over time by targeting aromatic L-amino acid decarboxylase. Furthermore, extensive research efforts based on viral vectors are currently ongoing in an attempt to better replicate the dopaminergic neurodegeneration phenomena inherent to the progressive intraneuronal aggregation of alpha-synuclein. Finally, a number of incoming strategies will soon emerge over the horizon, these being sustained by the underlying goal of promoting alpha-synuclein clearance, such as, for instance, gene therapy initiatives based on increasing the activity of glucocerebrosidase. To provide adequate proof-of-concept on safety and efficacy and to push forward true translational initiatives based on these different types of gene therapies before entering into clinical trials, the use of non-human primate models undoubtedly plays an instrumental role.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Parkinson Disease; Primates

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disease arising from the misfolding and accumulation of the protein α-synuclein in oligodendrocytes, where it forms glial cytoplasmic inclusions (GCIs). Several years of studying synthetic α-synuclein fibrils has provided critical insight into the ability of α-synuclein to template endogenous protein misfolding, giving rise to fibrillar structures capable of propagating from cell to cell. However, more recent studies with MSA-derived α-synuclein aggregates have shown that they have a similar ability to undergo template-directed propagation, like PrP prions. Almost 20 years after α-synuclein was discovered as the primary component of GCIs, α-synuclein aggregates isolated from MSA patient samples were shown to infect cultured mammalian cells and also to transmit neurological disease to transgenic mice. These findings argue that α-synuclein becomes a prion in MSA patients. In this review, we discuss the in vitro and in vivo data supporting the recent classification of MSA as a prion disease.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Multiple System Atrophy; Prion Diseases; Prions

Neurodegenerative diseases are highly debilitating conditions characterised primarily by progressive neuronal loss and impairment of the nervous system. Parkinson's disease (PD) is one of the most common of these disorders, affecting 1-2% of the population above the age of 65. Although the underlying mechanisms of PD have been extensively studied, we still lack a full understanding of the molecular underpinnings of the disease. Thus, the in vitro and in vivo models currently used are able to only partially recapitulate the typical phenotypes of the disease. Here, we review various cell culture models currently used to study the molecular basis of PD, with a focus on alpha-synuclein-associated molecular pathologies. We also discuss how different cell models may constitute powerful tools for high-throughput screening of molecules capable of modulating alpha-synuclein toxicity.

Topics: alpha-Synuclein; Animals; Cell Line; Disease Models, Animal; Drug Evaluation, Preclinical; Humans; Parkinson Disease; Phenotype

A major challenge in Parkinson disease (PD) will be to turn an emerging and expanding pipeline of novel disease-modifying candidate compounds into therapeutics. Novel targets need in vivo validation, and candidate therapeutics require appropriate preclinical platforms on which to define potential efficacy and target engagement before advancement to clinical development. We propose that α-synuclein (α-syn)-based mammalian models will be crucial for this process. Here, we review α-syn transgenic mouse models, viral vector models of α-syn overexpression and models of 'prion-like' spread of α-syn, and describe how each of these model types may contribute to PD drug discovery. We conclude by presenting our opinion on how to use a combination of these models through the late-stage preclinical, proof-of-principle investigation of novel therapeutics.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Disease Models, Animal; Drug Evaluation, Preclinical; Humans; Parkinson Disease

With the understanding that α-synuclein plays a major role in the pathogenesis of Parkinson's disease (PD), novel animal models have been developed for conducting preclinical research in screening novel disease modifying therapies. Advancements in research techniques in α-synuclein targeted disease modification have utilised methods such as viral mediated expression of human α-synuclein, as well as the inoculation of pathogenic α-synuclein species from Lewy Bodies of PD patients, for accurately modelling progressive self-propagating neurodegeneration. In applying these cutting-edge research tools with sophisticated trial designs in preclinical drug trials, a useful platform has emerged for developing candidate agents with disease modifying actions, promising a greater chance of success for clinical translation. In this article, we describe the transition of well-established animal models of PD symptomatology to newly developed models of PD pathogenesis, with specific focus on methods of viral-mediated and inoculation of pathogenic α-synuclein, that aim to aid scientific translation of neuroprotective strategies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Mutagenesis, Site-Directed; Neurons; Parkinson Disease

Starting two decades ago with the discoveries of genetic links between alpha-synuclein and Parkinson's disease risk and the identification of aggregated alpha-synuclein as the main protein constituent of Lewy pathology, alpha-synuclein has emerged as the major therapeutic target in Parkinson's disease and related synucleinopathies. Following the suggestion that alpha-synuclein pathology gradually spreads through the nervous system following a stereotypic pattern and the discovery that aggregated forms of alpha-synuclein can propagate pathology from one cell to another, and thereby probably aggravate existing deficits as well as generate additional symptoms, the idea that alpha-synuclein is a viable therapeutic target gained further support. In this review we describe current challenges and possibilities with alpha-synuclein as a therapeutic target. We briefly highlight gaps in the knowledge of the role of alpha-synuclein in disease, and propose that a deeper understanding of the pathobiology of alpha-synuclein can lead to improved therapeutic strategies. We describe several treatment approaches that are currently being tested in advanced animal experiments or already are in clinical trials. We have divided them into approaches that reduce alpha-synuclein production; inhibit alpha-synuclein aggregation inside cells; promote its degradation either inside or outside cells; and reduce its uptake by neighbouring cells following release from already affected neurons. Finally, we briefly discuss challenges related to the clinical testing of alpha-synuclein therapies, for example difficulties in monitoring target engagement and the need for relatively large trials of long duration. We conclude that alpha-synuclein remains one of the most compelling therapeutic targets for Parkinson's disease, and related synucleinopathies, and that the multitude of approaches being tested provides hope for the future.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genetic Therapy; Humans; Multiple System Atrophy; Neurons; Parkinson Disease

Parkinson's disease (PD) is the most common movement disorder associated with the elderly which, other than symptomatic therapies, has no effective treatment or preventive measures. Sirtuins and their pharmacological activators/inhibitors have been associated with a range of neuroprotective effects, and a large body of work on sirtuins' influence on PD pathology has accumulated over the past decade. Here, evidence for sirtuins' activities as modifiers of PD pathology and how the mammalian sirtuin paralogues may have conflicting impacts on PD pathogenesis and disease progression is reviewed. The possible cellular and molecular mechanisms underlying sirtuin activities in PD are discussed in the light of current knowledge with reference to autophagy, mitochondrial homeostasis, and microtubule dynamics. © 2016 Wiley Periodicals, Inc.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Enzyme Activators; Humans; Neurons; Neuroprotective Agents; Parkinson Disease; Sirtuins

Parkinson's disease is the second most common neurodegenerative disorder, with only partial symptomatic therapy and no mechanism-based therapies. The accumulation and aggregation of α-synuclein is causatively linked to the sporadic form of the disease, which accounts for 95% of cases. The pathology is a result of a gain of toxic function of misfolded α-synuclein conformers, which can template the aggregation of soluble monomers and lead to cellular dysfunction, at least partly by interfering with membrane fusion events at synaptic terminals. Here, we discuss the transcellular propagation and intracellular trafficking of α-synuclein and posit that endosomal processing could be a point of convergence between these two routes. Understanding these events will clarify the therapeutic potential of enzymes that regulate protein trafficking and degradation in synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Parkinson Disease; Protein Transport; SNARE Proteins

Aggregation of alpha-synuclein is implicated in several neurodegenerative diseases collectively termed synucleinopathies. Emerging evidence strongly implicates cell-to-cell transmission of misfolded alpha-synuclein as a common pathogenetic mechanism in synucleinopathies. The impact of alpha-synuclein pathology on neuronal dysfunction and behavioral impairments is being explored in animal models. This review provides an update on how research in animal models supports the concept that misfolded alpha-synuclein spreads from cell to cell and describes how findings in animal models might relate to the disease process in humans. Finally, we discuss the current underlying molecular and cellular mechanisms and future therapeutic strategies targeting alpha-synuclein propagation.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Neurodegenerative Diseases

Synucleinopathies are characterized by abnormal proteinaceous aggregates, mainly composed of fibrillar α-synuclein (α-syn). It is now believed that α-syn can form small aggregates in a restricted number of cells, that propagate to neighbouring cells and seed aggregation of endogenous α-syn, in a 'prion-like manner'. This process could underlie the stereotypical progression of Lewy bodies described by Braak and colleagues across different stages of Parkinson's disease (PD). This prion-like behaviour of α-syn has been recently investigated in animal models of PD or multiple system atrophy (MSA). These models investigate the cell-to-cell transfer of α-syn seeds, or the induction and spreading of α-syn pathology in transgenic or wild-type rodent brain. In this review, we first outline the involvement of α-syn in Lewy body diseases and MSA, and discuss how 'prion-like' mechanisms can contribute to disease. Thereon, we debate the relevance of animal models used to study prion-like propagation. Finally, we review current main histological methods used to assess α-syn pathology both in animal models and in human samples and their relevance to the disease. Specifically, we discuss using α-syn phosphorylated at serine 129 as a marker of pathology, and the novel methods available that allow for more sensitive detection of early pathology, which has relevance for modelling synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Disease Progression; Humans; Lewy Body Disease; Multiple System Atrophy

Immunotherapy using antibodies targeting alpha-synuclein has proven to be an effective strategy for ameliorating pathological and behavioral deficits induced by excess pathogenic alpha-synuclein in various animal and/or cellular models. However, the process of selecting the anti-alpha-synuclein antibody with the best potential to treat synucleinopathies in humans is not trivial. Critical to this process is a better understanding of the pathological processes involved in the synucleinopathies and how antibodies are able to influence these. We will give an overview of the first proof-of-concept studies in rodent disease models and discuss challenges associated with developing antibodies against alpha-synuclein resulting from the distribution and structural characteristics of the protein. We will also provide a status on the passive immunization approaches targeting alpha-synuclein that have entered, or are expected to enter, clinical evaluation.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Immunization, Passive; Lewy Body Disease; Multiple System Atrophy; Parkinson Disease

Multiple system atrophy (MSA) is a rare, yet rapidly-progressive neurodegenerative disease that presents clinically with autonomic failure in combination with parkinsonism or cerebellar ataxia. The definitive neuropathology differentiating MSA from Lewy body diseases is the presence of α-synuclein aggregates in oligodendrocytes (called glial cytoplasmic inclusion or GCI) rather than the fibrillar aggregates in neurons (called Lewy bodies). This makes the pathological pathway(s) in MSA unique in that oligodendrocytes are involved rather than predominantly neurons, as is most other neurodegenerative disorders. MSA is therefore regarded as an oligodendrogliopathy. The etiology of MSA is unknown. No definitive risk factors have been identified, although α-synuclein and other genes have been variably linked to MSA risk. Utilization of postmortem brain tissues has greatly advanced our understanding of GCI pathology and the subsequent neurodegeneration. However, extrapolating the early pathogenesis of MSA from such resource has been difficult and limiting. In recent years, cell and animal models developed for MSA have been instrumental in delineating unique MSA pathological pathways, as well as aiding in clinical phenotyping. The purpose of this review is to bring together and discuss various animal models that have been developed for MSA and how they have advanced our understanding of MSA pathogenesis, particularly the dynamics of α-synuclein aggregation. This review will also discuss how animal models have been used to explore potential therapeutic avenues for MSA, and future directions of MSA modeling.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Multiple System Atrophy; Oligodendroglia

Neurodegenerative disorders with alpha-synuclein (α-syn) accumulation (synucleinopathies) include Parkinson's disease (PD), PD dementia, dementia with Lewy bodies and multiple system atrophy (MSA). Due to the involvement of toxic α-syn aggregates in the molecular origin of these disorders, developing effective therapies targeting α-syn is a priority as a disease-modifying alternative to current symptomatic treatments. Importantly, the clinical and pathological attributes of MSA make this disorder an excellent candidate as a synucleinopathy model for accelerated drug development. Recent therapeutic strategies targeting α-syn in in vivo and in vitro models of MSA, as well as in clinical trials, have been focused on the pathological mechanisms of α-syn synthesis, aggregation, clearance, and/or cell-to-cell propagation of its neurotoxic conformers. Here we summarize the most relevant approaches in this direction, with emphasis on their potential as general synucleinopathy modifiers, and enumerate research areas for potential improvement in MSA drug discovery.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Multiple System Atrophy

Animal models of Parkinson's disease (PD) are important for understanding the mechanisms of the disease and can contribute to developing and validating novel therapeutics. Ideally, these models should replicate the cardinal features of PD, such as progressive neurodegeneration of catecholaminergic neurons and motor defects. Many current PD models emphasize pathological forms of α-synuclein, based on findings that autosomal dominant mutations in α-synuclein and duplications/triplications of the SNCA gene cause PD. In addition, Lewy bodies and Lewy neurites, primarily composed of α-synuclein, represent the predominant pathological characteristics of PD. These inclusions have defined features, such as insolubility in non-ionic detergent, hyperphosphorylation, proteinase K sensitivity, a filamentous appearance by electron microscopy, and β-sheet structure. Furthermore, it has become clear that Lewy bodies and Lewy neurites are found throughout the peripheral and central nervous system, and could account not only for motor symptoms, but also for non-motor symptoms of the disease. The goal of this review is to describe two new α-synuclein-based models: the recombinant adeno-associated viral vector-α-synuclein model and the α-synuclein fibril model. An advantage of both models is that they do not require extensive crossbreeding of rodents transgenic for α-synuclein with other rodents transgenic for genes of interest to study the impact of such genes on PD-related pathology and phenotypes. In addition, abnormal α-synuclein can be expressed in brain regions relevant for disease. Here, we discuss the features of each model, how each model has contributed thus far to our understanding of PD, and the advantages and potential caveats of each model. This review describes two α-synuclein-based rodent models of Parkinson's disease: the rAAV-α-synuclein model and the α-synuclein fibril model. The key features of these models are described, and the extent to which they recapitulate features of PD, such as α-synuclein inclusion formation, loss of dopaminergic synapses in the striatum, motor defects, inflammation, and dopamine neuron death. This article is part of a special issue on Parkinson disease.

Topics: alpha-Synuclein; Amyloid; Animals; Comprehension; Dependovirus; Disease Models, Animal; Genetic Vectors; Humans; Parkinson Disease; Recombinant Proteins

Developing new therapeutic strategies for Parkinson's disease requires cellular models. Current models reproduce the two most salient changes found in the brains of patients with Parkinson's disease: The degeneration of dopaminergic neurons and the existence of protein aggregates consisting mainly of α-synuclein. Cultured cells offer many advantages over studying Parkinson's disease directly in patients or in animal models. At the same time, the choice of a specific cellular model entails the requirement to focus on one aspect of the disease while ignoring others. This article is intended for researchers planning to use cellular models for their studies. It describes for commonly used cell types the aspects of Parkinson's disease they model along with technical advantages and disadvantages. It might also be helpful for researchers from other fields consulting literature on cellular models of Parkinson's disease. Important models for the study of dopaminergic neuron degeneration include Lund human mesencephalic cells and primary neurons, and a case is made for the use of non-dopaminergic cells to model pathogenesis of non-motor symptoms of Parkinson's disease. With regard to α-synuclein aggregates, this article describes strategies to induce and measure aggregates with a focus on fluorescent techniques. Cellular models reproduce the two most salient changes of Parkinson's disease, the degeneration of dopaminergic neurons and the existence of α-synuclein aggregates. This article is intended for researchers planning to use cellular models for their studies. It describes for commonly used cell types and treatments the aspects of Parkinson's disease they model along with technical advantages and disadvantages. Furthermore, this article describes strategies to induce and measure aggregates with a focus on fluorescent techniques. This article is part of a special issue on Parkinson disease.

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Humans; Parkinson Disease; Substantia Nigra

α-Synuclein, which is present as a small, soluble, cytosolic protein in healthy subjects, is converted to amyloid-like fibrils in diseases such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Bulk synthesis of purified α-synuclein has made it more convenient to study the nature of the normal protein and the mechanism of its conversion to an abnormal form in vitro and in vivo. Synthetic α-synuclein fibrils and pathological α-synuclein from diseased brains can act as triggers to convert normal α-synuclein to an abnormal form via prion-like mechanisms. In this article, we describe the experimental pathologies of α-synuclein both in vitro and in vivo in human and animal models. Prion-like spreading of abnormal α-synuclein from cell to cell can account for the progression of these α-synucleinopathies.

Topics: alpha-Synuclein; Amyloid; Animals; Brain; Disease Models, Animal; Disease Progression; Humans; Lewy Body Disease; Mice; Multiple System Atrophy; Parkinson Disease

Parkinson's disease (PD) is a devastating and progressive movement disorder characterized by symptoms of muscles rigidity, tremor, postural instability and slow physical movements. Biochemically, PD is characterized by lack of dopamine production and its action due to loss of dopaminergic neurons and neuropathologically by the presence of intracytoplasmic inclusions known as Lewy bodies, which mainly consist of presynaptic neuronal protein, α-synuclein (α-syn). It is believed that alteration in α-syn homeostasis leads to increased accumulation and aggregation of α-syn in Lewy body. Based on the important role of α-syn from pathogenesis to therapeutics, the recent researches are mainly focused on deciphering the critical role of α-syn at advanced level. Being a major protein in Lewy body that has a key role in pathogenesis of PD, several model systems including immortalized cell lines (SH-SY5Y), primary neuronal cultures, yeast (saccharomyces cerevisiae), drosophila (fruit flies), nematodes (Caenorhabditis elegans) and rodents are being employed to understand the PD pathogenesis and treatment. In order to study the etiopathogensis and develop novel therapeutic target for α -syn aggregation, majority of investigators rely on toxin (rotenone, 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine, 6-hydroxydopamine, paraquat)-induced animal models of PD as a tool for basic research. Whereas, cell and tissue based models are mostly utilized to elucidate the mechanistic and molecular pathways underlying the α -syn induced toxicity and therapeutic approaches in PD. Gene modified mouse models based on α-syn expression are fascinating for modeling familial PD and toxin induced models provide a suitable approach for sporadic PD. The purpose of this review is to provide a summary and a critical review of the involvement of α-syn in various in vitro and in vivo models of PD based on use of neurotoxins as well as genetic modifications.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Neurons; Neurotoxins; Parkinson Disease

In recent years, a new generation of animal models of Parkinson's disease (PD) based on ectopic expression, overexpression, or intracerebral injection of the protein α-synuclein have emerged. Critically, these models develop inclusions of aggregated α-synuclein and/or α-synuclein-mediated neuronal loss replicating the defining pathological hallmarks of PD and driving significant advances in the understanding of the pathogenic mechanisms underpinning PD. Here, we provide a comprehensive review of this new generation of animal models of PD, ranging from invertebrate to rodent to nonhuman primate. We focus on their strengths and limitations with respect to their highly anticipated contribution to the further understanding of α-synuclein pathobiology and the future testing of novel disease-modifying therapeutics.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drug Discovery; Humans; Neurons; Parkinson Disease; Prions

Multiple system atrophy (MSA) is a predominantly sporadic, adult-onset, fatal neurodegenerative disease of unknown etiology. MSA is characterized by autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal signs in any combination. MSA belongs to a group of neurodegenerative disorders termed α-synucleinopathies, which also include Parkinson's disease and dementia with Lewy bodies. Their common pathological feature is the occurrence of abnormal α-synuclein positive inclusions in neurons or glial cells. In MSA, the main cell type presenting aggregates composed of α-synuclein are oligodendroglial cells . This pathological hallmark, also called glial cytoplasmic inclusions (GCIs) , is associated with progressive and profound neuronal loss in various regions of the brain. The development of animal models of MSA is justified by the limited understanding of the mechanisms of neurodegeneration and GCIs formation, which is paralleled by a lack of therapeutic strategies. Two main types of rodent models have been generated to replicate different features of MSA neuropathology. On one hand, neurotoxin-based models have been produced to reproduce neuronal loss in substantia nigra pars compacta and striatum. On the other hand, transgenic mouse models with overexpression of α-synuclein in oligodendroglia have been used to reproduce GCIs-related pathology. This chapter gives an overview of the atypical Parkinson's syndrome MSA and summarizes the currently available MSA animal models and their relevance for pre-clinical testing of disease-modifying therapies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Multiple System Atrophy

In order to study the molecular pathways of Parkinson's disease (PD) and to develop novel therapeutic strategies, scientific investigators rely on animal models. The identification of PD-associated genes has led to the development of genetic PD models as an alternative to toxin-based models. Viral vector-mediated loco-regional gene delivery provides an attractive way to express transgenes in the central nervous system. Several vector systems based on various viruses have been developed. In this chapter, we give an overview of the different viral vector systems used for targeting the CNS. Further, we describe the different viral vector-based PD models currently available based on overexpression strategies for autosomal dominant genes such as α-synuclein and LRRK2, and knockout or knockdown strategies for autosomal recessive genes, such as parkin, DJ-1, and PINK1. Models based on overexpression of α-synuclein are the most prevalent and extensively studied, and therefore the main focus of this chapter. Many efforts have been made to increase the expression levels of α-synuclein in the dopaminergic neurons. The best α-synuclein models currently available have been developed from a combined approach using newer AAV serotypes and optimized vector constructs, production, and purification methods. These third-generation α-synuclein models show improved face and predictive validity, and therefore offer the possibility to reliably test novel therapeutics.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Genetic Vectors; Lentivirus; Parkinson Disease

Multiple system atrophy (MSA) is a sporadic, adult onset, relentlessly progressive neurodegenerative disease characterized by autonomic abnormalities associated with parkinsonism, cerebellar dysfunction, pyramidal signs, or combinations thereof. Treatments that can halt or reverse the progression of MSA have not yet been identified. MSA is neuropathologically defined by the presence of α-synuclein-containing inclusions, particularly in the cytoplasm of oligodendrocytes (glial cytoplasmic inclusions, GCIs), which are associated with neurodegeneration. The mechanisms by which oligodendrocytic α-synuclein inclusions cause neuronal death in MSA are not completely understood. The MSA neurodegenerative process likely comprises cell-to-cell transmission of α-synuclein in a prion-like manner, α-synuclein aggregation, increased oxidative stress, abnormal expression of tubulin proteins, decreased expression of neurotrophic factors, excitotoxicity and microglial activation, and neuroinflammation. In an attempt to block each of these pathogenic mechanisms, several pharmacologic approaches have been tried and shown to exert neuroprotective effects in transgenic mouse or cellular models of MSA. These include sertraline, paroxetine, and lithium, which hamper arrival of α-synuclein to oligodendroglia; rifampicin, lithium, and non-steroidal anti-inflammatory drugs, which inhibit α-synuclein aggregation in oligodendrocytes; riluzole, rasagiline, fluoxetine and mesenchymal stem cells, which exert neuroprotective actions; and minocycline and intravenous immunoglobulins, which reduce neuroinflammation and microglial activation. These and other potential therapeutic strategies for MSA are summarized in this review.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Disease Models, Animal; Disease Progression; Humans; Mice; Multiple System Atrophy; Neurodegenerative Diseases; Neuroprotective Agents; Oligodendroglia

The pathological hallmark of Parkinson's disease (PD) is the loss of dopaminergic neurons in the substantia nigra pars compacta and the presence of Lewy bodies (LBs). LBs are intracellular inclusions typically found in these neurons and in noradrenergic neurons of the locus coeruleus in patients with PD. However, LBs can be found more widely in neurons of the olfactory bulb, cerebral cortex, and spinal cord. Additionally, LBs appear in neurons of the cardiac, cutaneous, and intestinal autonomic nervous systems. LBs are composed of fibrillar aggregates of α-synuclein (α-syn). The widespread distribution of LBs indicates that α-syn aggregation occurs in neurons in various areas, supporting the concept that PD is not only a simple movement disorder but also a complex one with nonmotor impairments. However, it is unclear how α-syn pathology spreads in the nervous system. Postmortem analyses of patients with PD who received transplants of fetal mesencephalic dopaminergic neurons revealed LB formation in surviving grafts, providing a crucial clue regarding the host-to-graft disease propagation. Recent experiments demonstrated that fibrillar α-syn is transferred from neurons to neurons in cellular and animal models, suggesting that fibrillar α-syn is repeatedly generated in cells by triggering the continuous conversion of normal soluble species into fibrillar ones. These findings suggest a "prion-like" mechanism for α-syn propagation in the pathogenesis of PD. This review summarizes the experimental findings on the prion-like propagation of α-syn and discusses the potential of cellular and animal models for testing the protective effects of chemical agents against neurodegeneration in PD.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Disease Models, Animal; Humans; Models, Biological; Parkinson Disease; Prions

The aggregation of alpha-synuclein (aSyn) has been implicated in a number of degenerative diseases collectively termed synucleinopathies. Although most cases of synucleinopathies are idiopathic in nature, there are familial cases of these diseases that are due to mutations or multiplications of the gene coding for aSyn. Two of the most common synucleinopathies are Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Both of these diseases present with cognitive deficits, though with different clinical and temporal features. In PD, cognitive deficits are subtle, may occur before the onset of the classical motor symptoms, and only occasionally lead to dementia in the later stages of the disease. In contrast, dementia is the dominating feature of DLB from the disease onset. The impact of aSyn pathology on the development of neurobiological and behavioral impairments can be investigated using rodent models. There are currently several lines of transgenic mice overexpressing wild-type or mutated aSyn under various promoters. This review will provide an updated synopsis of the mouse lines available, summarize their cognitive deficits, and reflect on how deficits observed in these mice relate to the disease process in humans. In addition, we will review mouse lines where knockout strategies have been applied to study the effects of aSyn on various cognitive tasks and comment on how these lines have been used in combination with other transgenic strains, or with human aSyn overexpression by viral vectors. Finally, we will discuss the recent advent of bacterial artificial chromosome (BAC) transgenic models of PD and their effectiveness in modeling cognitive decline in PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cognition Disorders; Dementia; Disease Models, Animal; Mice; Parkinson Disease; Rats

Alzheimer's disease (AD), the most common form of dementia, is characterized histopathologically by the deposition of β-amyloid (Aβ) plaques and neurofibrillary tangles-containing hyperphosphorylated tau protein in the brain. Parkinson's disease (PD), the most common movement disorder, is characterized by the aggregation of α-synuclein protein in Lewy body inclusions and the death of dopaminergic neurons in the substantia nigra. Based on their pathological signatures, AD and PD can be considered as two different disease entities. However, a subpopulation of PD patients also exhibit Aβ plaques, and AD patients exhibit α-synuclein aggregates. This overlap between PD and AD suggests that common pathological pathways exist for the two diseases. Identification of factors and cellular mechanisms by which these factors can trigger pathological hallmarks for AD/PD overlap may help in designing disease-modifying therapies that can reverse or stop the progression of AD and PD. For the last decade, work in our laboratory has shown that fluctuations in the levels of cholesterol oxidation products (oxysterols) may correlate with the onset of AD and PD. In this review, we will provide results from our laboratory and data from literature that converge to strongly suggest the involvement of cholesterol and cholesterol oxidation products in the pathogenesis of AD and PD. We will specifically delineate the role of and the underlying mechanisms by which increased levels of the oxysterol 27-hydroxycholesterol contribute to the pathogenesis of AD, PD, and AD/PD overlap.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Brain; Cholesterol, Dietary; Disease Models, Animal; Endoplasmic Reticulum Stress; Homeostasis; Humans; Hydroxycholesterols; Lipid Metabolism; Liver X Receptors; Orphan Nuclear Receptors; Parkinson Disease; Plaque, Amyloid; Rabbits

Parkinson's disease (PD) is the second most common neurodegenerative disorder, leading to a variety of motor and non-motor symptoms. Interestingly, non-motor symptoms often appear a decade or more before the first signs of motor symptoms. Some of these non-motor symptoms are remarkably similar to those observed in cases of impaired neurogenesis and several PD-related genes have been shown to play a role in embryonic or adult neurogenesis. Indeed, animal models deficient in Nurr1, Pitx3, SNCA and PINK1 display deregulated embryonic neurogenesis and LRRK2 and VPS35 have been implicated in neuronal development-related processes such as Wnt/β-catenin signaling and neurite outgrowth. Moreover, adult neurogenesis is affected in both PD patients and PD animal models and is regulated by dopamine and dopaminergic (DA) receptors, by chronic neuroinflammation, such as that observed in PD, and by differential expression of wild-type or mutant forms of PD-related genes. Indeed, an increasing number of in vivo studies demonstrate a role for SNCA and LRRK2 in adult neurogenesis and in the generation and maintenance of DA neurons. Finally, the roles of PD-related genes, SNCA, LRRK2, VPS35, Parkin, PINK1 and DJ-1 have been studied in NSCs, progenitor cells and induced pluripotent stem cells, demonstrating a role for some of these genes in stem/progenitor cell proliferation and maintenance. Together, these studies strongly suggest a link between deregulated neurogenesis and the onset and progression of PD and present strong evidence that, in addition to a neurodegenerative disorder, PD can also be regarded as a developmental disorder.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; MicroRNAs; Neural Stem Cells; Neurogenesis; Parkinson Disease; Protein Serine-Threonine Kinases

Since their introduction in 1996, animal models of multiple system atrophy (MSA) have generated important insights into pathogenesis and interventional therapies. Toxin and genetic approaches have been used alone or in combination to replicate progressive motor and non-motor symptoms reflecting human neuropathology. Here, we review these developments and discuss the advantages and limitations of the MSA animal models, as well as their application in preclinical target validation.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autonomic Nervous System; Biomarkers; Disease Models, Animal; Haplorhini; Mice; Multiple System Atrophy; Neurotoxins; Rats

Classically defined phenotypically by a triad of cerebellar ataxia, parkinsonism, and autonomic dysfunction in conjunction with pyramidal signs, multiple system atrophy (MSA) is a rare and progressive neurodegenerative disease affecting an estimated 3-4 per every 100,000 individuals among adults 50-99 years of age. With a pathological hallmark of alpha-synuclein-immunoreactive glial cytoplasmic inclusions (GCIs; Papp-Lantos inclusions), MSA patients exhibit marked neurodegenerative changes in the striatonigral and/or olivopontocerebellar structures of the brain. As a member of the alpha-synucleinopathy family, which is defined by its well-demarcated alpha-synuclein-immunoreactive inclusions and aggregation, MSA's clinical presentation exhibits several overlapping features with other members including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Given the extensive fund of knowledge regarding the genetic etiology of PD revealed within the past several years, a genetic investigation of MSA is warranted. While a current genome-wide association study is underway for MSA to further clarify the role of associated genetic loci and single-nucleotide polymorphisms, several cases have presented solid preliminary evidence of a genetic etiology. Naturally, genes and variants manifesting known associations with PD (and other phenotypically similar neurodegenerative disorders), including SNCA and MAPT, have been comprehensively investigated in MSA patient cohorts. More recently variants in COQ2 have been linked to MSA in the Japanese population although this finding awaits replication. Nonetheless, significant positive associations with subsequent independent replication studies have been scarce. With very limited information regarding genetic mutations or alterations in gene dosage as a cause of MSA, the search for novel risk genes, which may be in the form of common variants or rare variants, is the logical nexus for MSA research. We believe that the application of next generation genetic methods to MSA will provide valuable insight into the underlying causes of this disease, and will be central to the identification of etiologic-based therapies.

Topics: Alkyl and Aryl Transferases; alpha-Synuclein; Animals; Disease Models, Animal; Genetic Linkage; Genome-Wide Association Study; Humans; Lewy Body Disease; Multiple System Atrophy; Mutation; Parkinson Disease

Parkinson's disease is an incurable neurodegenerative disease. Most cases of the disease are of sporadic origin, but about 10% of the cases are familial. The genes thus far identified in Parkinson's disease are well conserved. Drosophila is ideally suited to study the molecular neuronal cell biology of these genes and the pathogenic mutations in Parkinson's disease. Flies reproduce quickly, and their elaborate genetic tools in combination with their small size allow researchers to analyze identified cells and neurons in large numbers of animals. Furthermore, fruit flies recapitulate many of the cellular and molecular defects also seen in patients, and these defects often result in clear locomotor and behavioral phenotypes, facilitating genetic modifier screens. Hence, Drosophila has played a prominent role in Parkinson's disease research and has provided invaluable insight into the molecular mechanisms of this disease.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drosophila; Drosophila Proteins; Humans; Parkinson Disease

Microtubules (MTs) are dynamic polymers consisting of α/β tubulin dimers and playing a plethora of roles in eukaryotic cells. Looking at neurons, they are key determinants of neuronal polarity, axonal transport and synaptic plasticity. The concept that MT dysfunction can participate in, and perhaps lead to, Parkinson's disease (PD) progression has been suggested by studies using toxin-based and genetic experimental models of the disease. Here, we first learn lessons from MPTP and rotenone as well as from the PD related genes, including SNCA and LRRK2, and then look at old and new evidence regarding the interplay between parkin and MTs. Data from experimental models and human cells point out that parkin regulates MT stability and strengthen the link between MTs and PD paving the way to a viable strategy for the management of the disease.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Microtubules; Mutation; Neurons; Parkinson Disease, Secondary; Protein Serine-Threonine Kinases; Rotenone; Tubulin; Ubiquitin-Protein Ligases

Neuroinflammation is increasingly recognized as a key factor in the pathogenesis of neurodegenerative conditions. However, it remains unclear whether it has a protective or damaging role. Studies of Alzheimer's disease and Parkinson's disease have provided much of the evidence for inflammatory pathology in neurodegeneration. Here we review the evidence for inflammation in dementia with Lewy bodies and Parkinson's disease dementia. Neuroinflammation has been confirmed in vivo using PET imaging, with microglial activation seen in Parkinson's disease dementia and recently in dementia with Lewy bodies. In Parkinson's disease and Parkinson's disease dementia, microglial activation suggests a chronic inflammatory process, although there is also evidence of its association with cognitive ability and neuronal function. Alpha-synuclein in various conformations has also been linked to activation of microglia, with a broad range of components of the innate and adaptive immune systems associated with this interaction. Evidence of neuroinflammation in Lewy body dementia is further supported by pathological and biomarker studies. Genetic and epidemiological studies support a role for inflammation in Parkinson's disease, but have yet to provide the same for Lewy body dementia. This review highlights the need to identify whether the nature and extent of microglial activation in Lewy body dementia can be linked to structural change, progression of domain specific cognitive symptoms and peripheral inflammation as a marker of central microglial pathology. Answers to these questions will enable the evaluation of immunotherapies as potential therapeutic options for prevention or treatment of dementia with Lewy bodies and Parkinson's disease dementia.

Topics: Adaptive Immunity; alpha-Synuclein; Animals; Biomarkers; Cytokines; Disease Models, Animal; Forecasting; Genetic Predisposition to Disease; Genome-Wide Association Study; HLA-D Antigens; Humans; Inflammation; Lewy Body Disease; Microglia; Positron-Emission Tomography

In this review, we consider the use of nonhuman primate (NHP) models of Parkinson's disease (PD) produced using viral-mediated gene delivery and information they provide in comparison to other model systems in rodents and NHPs. To date, rodent and NHP PD models have found it difficult to fully recapitulate the human disorder and, therefore, provide little actual insight into disease progression. The viral-mediated gene delivery method for α-synuclein has been shown to produce a parkinsonian rodent and NHP. This novel viral-mediated gene transfer model in the NHP appears to provide a significant advance beyond neurotoxicant models, by more closely mimicking the more chronic time course of developed behavioral deterioration and neuropathology. Although we agree that the use of these novel methods inducing parkinsonian NHPs may provide relevant treatment insights, beyond those of more standard PD models, we remain cautious as to the preclinical models' ability to predict outcomes in human trials. In specific cases of certain novel medical therapeutics, therefore, we also consider the phase 0 clinical trial as offering an alternative to the currently non-predictive preclinical models, including those in the NHP.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Gene Transfer Techniques; Macaca; Parkinson Disease

Parkinson's disease is a common neurodegenerative disease characterised by the loss of dopaminergic neurons in the substantia nigra pars compacta and the formation of α-synuclein aggregates found in Lewy bodies throughout the brain. Several α-synuclein transgenic mouse models have been generated, as well as viral-mediated overexpression of wild-type and mutated α-synuclein to mimic the disease and to delineate the pathogenic pathway of α-synuclein-mediated toxicity and neurodegeneration. In this review, we will recapitulate what we have learned about the function of α-synuclein and α-synuclein-mediated toxicity through studies of transgenic animal models, inducible animal models and viral-based models.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Humans; Parkinson Disease

Multiple system atrophy (MSA) is a fatal adult-onset neurodegenerative disorder of uncertain etiopathogenesis manifesting with autonomic failure, parkinsonism, and ataxia in any combination. The underlying neuropathology affects central autonomic, striatonigral and olivopontocerebellar pathways and it is associated with distinctive glial cytoplasmic inclusions (GCIs, Papp-Lantos bodies) that contain aggregates of α-synuclein. Current treatment options are very limited and mainly focused on symptomatic relief, whereas disease modifying options are lacking. Despite extensive testing, no neuroprotective drug treatment has been identified up to now; however, a neurorestorative approach utilizing autologous mesenchymal stem cells has shown remarkable beneficial effects in the cerebellar variant of MSA. Here, we review the progress made over the last decade in defining pathogenic targets in MSA and summarize insights gained from candidate disease-modifying interventions that have utilized a variety of well-established preclinical MSA models. We also discuss the current limitations that our field faces and suggest solutions for possible approaches in cause-directed therapies of MSA.

Topics: alpha-Synuclein; Animals; Biomarkers; Clinical Trials as Topic; Disease Models, Animal; Humans; Mitochondria; Multiple System Atrophy; Oxidative Stress

Multiple system atrophy (MSA) is a late-onset, sporadic neurodegenerative disorder clinically characterized by autonomic failure and either poorly levodopa-responsive parkinsonism or cerebellar ataxia. It is neuropathologically defined by widespread and abundant central nervous system α-synuclein-positive glial cytoplasmic inclusions and striatonigral and/or olivopontocerebellar neurodegeneration. There are two clinical subtypes of MSA distinguished by the predominant motor features: the parkinsonian variant (MSA-P) and the cerebellar variant (MSA-C). Despite recent progress in understanding the pathobiology of MSA, investigations into the symptomatology and natural history of the cerebellar variant of the disease have been limited. MSA-C presents a unique challenge to both clinicians and researchers alike. A key question is how to distinguish early in the disease course between MSA-C and other causes of adult-onset cerebellar ataxia. This is a particularly difficult question, because the clinical framework for conceptualizing and studying sporadic adult-onset ataxias continues to undergo flux. To date, several investigations have attempted to identify clinical features, imaging, and other biomarkers that may be predictive of MSA-C. This review presents a clinically oriented overview of our current understanding of MSA-C with a focus on evidence for distinguishing MSA-C from other sporadic, adult-onset ataxias.

Topics: alpha-Synuclein; Animals; Cerebellar Ataxia; Cerebellum; Disease Models, Animal; Humans; Multiple System Atrophy; Parkinsonian Disorders

Parkinson disease is the second most common neurodegenerative disease in the world, but there is currently no available cure for it. Current treatments only alleviate some of the symptoms for a few years, but they become ineffective in the long run and do not stop the disease. Therefore it is of outmost importance to develop therapeutic strategies that can prevent, stop, or cure Parkinson disease. A very promising target for these therapies is the peripheral immune system due to its probable involvement in the disease and its potential as a tool to modulate neuroinflammation. But for such strategies to be successful, we need to understand the particular state of the peripheral immune system during Parkinson disease in order to avoid its weaknesses. In this review we examine the available data regarding how dopamine regulates the peripheral immune system and how this regulation is affected in Parkinson disease; the specific cytokine profiles observed during disease progression and the alterations documented to date in patients' peripheral blood mononuclear cells. We also review the different strategies used in Parkinson disease animal models to modulate the adaptive immune response to salvage dopaminergic neurons from cell death. After analyzing the evidence, we hypothesize the need to prime the immune system to restore natural tolerance against α-synuclein in Parkinson disease, including at the same time B and T cells, so that T cells can reprogram microglia activation to a beneficial pattern and B cell/IgG can help neurons cope with the pathological forms of α-synuclein.

Topics: alpha-Synuclein; Animals; Cytokines; Disease Models, Animal; Dopamine; Humans; Immune System; Immune Tolerance; Immunologic Factors; Leukocytes, Mononuclear; Parkinson Disease; Vaccination

Parkinson's disease (PD) is a degenerative disease of the central nervous system, of which patomechanizm entirely is not clear. In the picture neuropathologically there is observed degeneration and loss of dopaminergic neurons, but also noradrenergic, serotonergic and cholinergic neurons in patients with PD. It is believed, that causes of PD are both environmental and genetic factors, associated mainly with mutations in the SNCA and PRKN genes, which may lead to changes in the structure of proteins such as alpha-synuclein (ASN) and Parkin. In neurons, disorders of the protein structure can lead to its aggregation and formation of soluble oligomers and insoluble filaments in the form of Lewy bodies and Lewy neuritis. In PD aggregation of ASN can be modulated by many factors like: oxidative stress, other neuronal proteins, Parkin, catecholamines especially dopamine, and mutations of SNCA gene. It also appears that some impact on the aggregation of ASN may have destabilizing factors of ASN tetramers. That, does ASN may become a new point for pharmacotherapy in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Gene Expression; Humans; Mutation; Oxidative Stress; Parkinson Disease; Proteasome Endopeptidase Complex; Proteolysis; Ubiquitin-Protein Ligases

Parkinson disease (PD; MIM 168600) is the second most common progressive neurodegenerative disorder characterized by a variety of motor and non-motor features. To date, at least 20 loci and 15 disease-causing genes for parkinsonism have been identified. Among them, the α-synuclein (SNCA) gene was associated with PARK1/PARK4. Point mutations, duplications and triplications in the SNCA gene cause a rare dominant form of PD in familial and sporadic PD cases. The α-synuclein protein, a member of the synuclein family, is abundantly expressed in the brain. The protein is the major component of Lewy bodies and Lewy neurites in dopaminergic neurons in PD. Further understanding of its role in the pathogenesis of PD through various genetic techniques and animal models will likely provide new insights into our understanding, therapy and prevention of PD.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Drosophila; Genetic Variation; Haplorhini; Humans; Mice; Parkinson Disease; Rats

Prions are self-propagating protein conformers that cause a variety of neurodegenerative disorders in humans and animals. Mouse models have played key roles in deciphering the biology of prions and in assessing candidate therapeutics. The development of transgenic mice that form prions spontaneously in the brain has advanced our understanding of sporadic and genetic prion diseases. Furthermore, the realization that many proteins can become prions has necessitated the development of mouse models for assessing the potential transmissibility of common neurodegenerative diseases. As the universe of prion diseases continues to expand, mouse models will remain crucial for interrogating these devastating illnesses.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Mutation; Parkinson Disease; Prion Diseases; Prions; tau Proteins

In Parkinson's disease (PD) and other synucleinopathies, chronic neurodegeneration occurs within different areas of the central nervous system leading to progressive motor and nonmotor symptoms. The symptomatic treatment options that are currently available do not slow or halt disease progression. This highlights the need of a better understanding of disease mechanisms and disease models. The generation of newborn neurons in the adult hippocampus and in the subventricular zone/olfactory bulb system is affected by many different regulators and possibly involved in memory processing, depression, and olfaction, symptoms which commonly occur in PD. The pathology of the adult neurogenic niches in human PD patients is still mostly elusive, but different preclinical models have shown profound alterations of adult neurogenesis. Alterations in stem cell proliferation, differentiation, and survival as well as neurite outgrowth and spine formation have been related to different aspects in PD pathogenesis. Therefore, neurogenesis in the adult brain provides an ideal model to study disease mechanisms and compounds. In addition, adult newborn neurons have been proposed as a source of endogenous repair. Herein, we review current knowledge about the adult neurogenic niches in PD and highlight areas of future research.

Topics: Adult; alpha-Synuclein; Animals; Animals, Genetically Modified; Cell Survival; Disease Models, Animal; Female; Hippocampus; Humans; Lateral Ventricles; Male; Neurogenesis; Neuronal Plasticity; Neurons; Parkinson Disease

Parkinson's disease (PD) is not only characterized by motor disturbances but also, by cognitive, sensory, psychiatric and autonomic dysfunction. It has been proposed that some of these symptoms might be related to the widespread pathology of α-synuclein (α-syn) aggregation in different nuclei of the central and peripheral nervous system. However, the pathogenic formation of α-syn aggregates in different brain areas of PD patients is poorly understood. Most experimental models of PD are valuable to assess specific aspects of its pathogenesis, such as toxin-induced dopaminergic neurodegeneration. However, new models are required that reflect the widespread and progressive formation of α-syn aggregates in different brain areas. Such α-syn aggregation is induced in only a few animal models, for example perikaryon inclusions are found in rats administered rotenone, aggregates with a neuritic morphology develop in mice overexpressing either mutated or wild-type α-syn, and in Smad3 deficient mice, aggregates form extensively in the perikaryon and neurites of specific brain nuclei. In this review we focus on α-syn aggregation in the human disorder, its genetics and the availability of experimental models. Indeed, evidences show that dopamine (DA) metabolism may be related to α-syn and its conformational plasticity, suggesting an interesting link between the two pathological hallmarks of PD: dopaminergic neurodegeneration and Lewy body (LB) formation.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Glucosylceramidase; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lewy Bodies; Mice; Mutation; Parkinson Disease; Protein Aggregates; Protein Serine-Threonine Kinases; Rats

The role of neuroinflammation and the adaptive immune system in PD (Parkinson's disease) has been the subject of intense investigation in recent years, both in animal models of parkinsonism and in post-mortem PD brains. However, how these processes relate to and modulate α-syn (α-synuclein) pathology and microglia activation is still poorly understood. Specifically, how the peripheral immune system interacts, regulates and/or is induced by neuroinflammatory processes taking place during PD is still undetermined. We present herein a comprehensive review of the features and impact that neuroinflamation has on neurodegeneration in different animal models of nigral cell death, how this neuroinflammation relates to microglia activation and the way microglia respond to α-syn in vivo. We also discuss a possible role for the peripheral immune system in animal models of parkinsonism, how these findings relate to the state of microglia activation observed in these animal models and how these findings compare with what has been observed in humans with PD. Together, the available data points to the need for development of dual therapeutic strategies that modulate microglia activation to change not only the way microglia interact with the peripheral immune system, but also to modulate the manner in which microglia respond to encounters with α-syn. Lastly, we discuss the immune-modulatory strategies currently under investigation in animal models of parkinsonism and the degree to which one might expect their outcomes to translate faithfully to a clinical setting.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Lymphocytes; Microglia; Neurons; Parkinson Disease

Over the last two decades, significant strides has been made toward acquiring a better knowledge of both the etiology and pathogenesis of Parkinson's disease (PD). Experimental models are of paramount importance to obtain greater insights into the pathogenesis of the disease. Thus far, neurotoxin-based animal models have been the most popular tools employed to produce selective neuronal death in both in vitro and in vivo systems. These models have been commonly referred to as the pathogenic models. The current trend in modeling PD revolves around what can be called the disease gene-based models or etiologic models. The value of utilizing multiple models with a different mechanism of insult rests on the premise that dopamine-producing neurons die by stereotyped cascades that can be activated by a range of insults, from neurotoxins to downregulation and overexpression of disease-related genes. In this position article, we present the relevance of both pathogenic and etiologic models as well as the concept of clinically relevant designs that, we argue, should be utilized in the preclinical development phase of new neuroprotective therapies before embarking into clinical trials.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genetic Vectors; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mice, Transgenic; Mutation; Neuroprotective Agents; Neurotoxins; Parkinson Disease; Protein Serine-Threonine Kinases

Parkinson's disease (PD), the second most common neurodegenerative disorder, affects 1-2 % of humans aged 60 years and older. The diagnosis of PD is based on motor symptoms such as bradykinesia, rigidity, tremor, and postural instability associated with the striatal dopaminergic deficit that is linked to neurodegenerative processes in the substantia nigra (SN). In the past, cellular replacement strategies have been evaluated for their potential to alleviate these symptoms. Adult neurogenesis, the generation of new neurons within two proliferative niches in the adult brain, is being intensively studied as one potential mode for cell-based therapies. The subventricular zone provides new neurons for the olfactory bulb functionally contributing to olfaction. The subgranular zone of the hippocampus produces new granule neurons for the dentate gyrus, required for memory formation and proper processing of anxiety provoking stimuli. Recent years have revealed that PD is associated with non-motor symptoms such as hyposmia, anhedonia, lack of novelty seeking behavior, depression, and anxiety that are not directly associated with neurodegenerative processes in the SN. This broad spectrum of non-motor symptoms may partly rely on proper olfactorial processing and hippocampal function. Therefore, it is conceivable that some non-motor deficits in PD are related to defective adult neurogenesis. Accordingly, in animal models and postmortem studies of PD, adult neurogenesis is severely affected, although the exact mechanisms and effects of these changes are not yet fully understood or are under debate due to conflicting results. Here, we review the current concepts related to the dynamic interplay between endogenous cellular plasticity and PD-associated pathology.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Hippocampus; Humans; Neurogenesis; Olfactory Bulb; Parkinson Disease

The discovery of α-synuclein has had profound implications concerning our understanding of Parkinson's disease (PD) and other neurodegenerative disorders characterized by α-synuclein accumulation. In fact, as compared with pre-α-synuclein times, a "new" PD can now be described as a whole-body disease in which a progressive spreading of α-synuclein pathology underlies a wide spectrum of motor as well as nonmotor clinical manifestations. Not only is α-synuclein accumulation a pathological hallmark of human α-synucleinopathies but increased protein levels are sufficient to trigger neurodegenerative processes. α-Synuclein elevations could also be a mechanism by which disease risk factors (e.g., aging) increase neuronal vulnerability to degeneration. An important corollary to the role of enhanced α-synuclein in PD pathogenesis is the possibility of developing α-synuclein-based biomarkers and new therapeutics aimed at suppressing α-synuclein expression. The use of in vitro and in vivo experimental models, including transgenic mice overexpressing α-synuclein and animals with viral vector-mediated α-synuclein transduction, has helped clarify pathogenetic mechanisms and therapeutic strategies involving α-synuclein. These models are not devoid of significant limitations, however. Therefore, further pursuit of new clues on the cause and treatment of PD in this post-α-synuclein era would benefit substantially from the development of improved research paradigms of α-synuclein elevation.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Biomarkers; Disease Models, Animal; Gene Expression Regulation; Genetic Vectors; Haplorhini; Humans; Lentivirus; Mice; Neurodegenerative Diseases; Rats; Treatment Outcome

Parkinson's disease is the most common neurodegenerative movement disorder. The motor impairments of Parkinson's disease are caused by the loss of dopaminergic neurons in the substantia nigra and associated with the appearance of fibrillar aggregates of α-synuclein (α-syn) called Lewy bodies. Approximately 90% of α-syn deposited in Lewy bodies is phosphorylated at serine 129 (Ser129). In contrast, only 4% or less of total α-syn is phosphorylated at this residue in the normal brain. This suggests that the accumulation of Ser129-phosphorylated α-syn leads to the formation of Lewy bodies and dopaminergic neurodegeneration in Parkinson's disease. Our laboratory and others have performed experiments using in vivo models of Parkinson's disease to elucidate the role of increased Ser129 phosphorylation in α-syn neurotoxicity. However, there has been a lack of consistency among these models. In this review, we summarize the main findings regarding the relationship between Ser129 phosphorylation and α-syn neurotoxicity, and examine the differences among models. We further discuss the role of Ser129 phosphorylation in α-syn aggregation and the future directions to test the potential of Ser129 phosphorylation as a therapeutic target for slowing the progression of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Nerve Degeneration; Parkinson Disease; Phosphorylation; Serine

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by the selective loss of dopaminergic neurons of the substantia nigra pars compacta and the accumulation of intracellular inclusions containing α-synuclein (αSyn). Growing evidence from studies in human PD brain, in addition to genetic and toxicological models, indicates that endoplasmic reticulum (ER) stress is a common feature of the disease and contributes to neurodegeneration. Recent reports place ER dysfunction as an early component of PD pathogenesis, and in this article we review the impact of ER stress in PD models and discuss the multiple mechanisms underlying the perturbation of secretory pathway function. Possible therapeutic strategies to mitigate ER stress in the context of PD are also discussed.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Endoplasmic Reticulum Stress; Humans; Parkinson Disease; Protein Unfolding; Substantia Nigra; Unfolded Protein Response

Although almost 50 years have passed since impaired dopaminergic transmission was identified as the main neurochemical defect in Parkinson's disease (PD), the cause of the disease remains unknown. A restricted number of biological mechanisms are likely to contribute to the process of cell death in the nigrostriatal pathway. These mechanisms include mitochondrial defects and enhanced formation of reactive oxygen species--leading to oxidative damage--and abnormal protein aggregation. In addition to or, possibly, intermingled with these mechanisms of neuronal damage there is another crucial factor: neuroinflammation. The inflammatory response associated with cell loss in the dopaminergic nigrostriatal tract and, more in general, the role of immune mechanisms are increasingly recognized in PD pathogenesis. Neuroinflammatory changes have been repeatedly demonstrated, in both neurotoxic and transgenic animal models of PD, as well as in PD patients. Transgenic models based on α-synuclein overexpression, in particular, have provided crucial insights into the correlation between this protein and the dichotomous response that microglia can activate, with the polarization toward a cytotoxic (M1) or cytoprotective (M2) phenotype. Full understanding of such mechanisms may set the ground for a fine tuning of the neuroinflammatory process that accompanies and sustains neurodegeneration, thereby opening new therapeutic perspectives for PD.

Topics: Adaptive Immunity; alpha-Synuclein; Animals; Disease Models, Animal; Humans; Immunity, Innate; Mitochondrial Diseases; Nervous System; Neuritis; Neuroimmunomodulation; Oxidative Stress; Parkinson Disease

Altered protein handling is thought to play a key role in the etiopathogenesis of Parkinson's disease (PD), as the disorder is characterized neuropathologically by the accumulation of intraneuronal protein aggregates (Lewy bodies and Lewy neurites). Attention has particularly focused on the α-synuclein protein, as it is the principal component of Lewy pathology. Moreover, point mutations in the α-synuclein gene cause rare familial forms of PD. Importantly, duplication/triplication of the wild type α-synuclein gene also cause a form of PD, indicating that increased levels of the normal α-synuclein protein is sufficient to cause the disease. Further, single nucleotide polymorphisms in the α-synuclein gene are associated with an increased risk of developing sporadic PD. Recent evidence now suggests the possibility that α-synuclein is a prion-like protein and that PD is a prion-like disease. Within cells, α-synuclein normally adopts an α-helical conformation. However, under certain circumstances, the protein can undergo a profound conformational transition to a β-sheet-rich structure that polymerizes to form toxic oligomers and amyloid plaques. Recent autopsy studies of patients with advanced PD who received transplantation of fetal nigral mesencephalic cells more than a decade earlier demonstrated that typical Lewy pathology had developed within grafted neurons. This suggests that α-synuclein in an aberrantly folded, β-sheet-rich form had migrated from affected to unaffected neurons. Laboratory studies confirm that α-synuclein can transfer from affected to unaffected nerve cells, where it appears that the misfolded protein can act as a template to promote misfolding of host α-synuclein. This leads to the formation of larger aggregates, neuronal dysfunction, and neurodegeneration. Indeed, recent reports demonstrate that a single intracerebral inoculation of misfolded α-synuclein can induce Lewy-like pathology in cells that can spread from affected to unaffected regions and can induce neurodegeneration with motor disturbances in both transgenic and normal mice. Further, inoculates derived from the brains of elderly α-synuclein-overexpressing transgenic mice have now been shown to accelerate the disease process when injected into the brains of young transgenic animals. Collectively, these findings support the hypothesis that α-synuclein is a prion-like protein that can adopt a self-propagating conformation that causes neurodegeneration. We propose that this mec

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Mutation; Neuroprotective Agents; Parkinson Disease; Prion Diseases; Protein Structure, Secondary

Mitochondria are highly dynamic, multifunctional organelles. Aside from their major role in energy metabolism, they are also crucial for many cellular processes including neurotransmission, synaptic maintenance, calcium homeostasis, cell death, and neuronal survival.. Increasing evidence supports a role for abnormal mitochondrial function in the molecular pathophysiology of Parkinson's disease (PD). For three decades we have known that mitochondrial toxins are capable of producing clinical parkinsonism in humans. PD is the most common neurodegenerative movement disorder that is characterized by the progressive loss of substantia nigra dopaminergic neurons leading to a deficiency of striatal dopamine. Although the neuropathology underlying the disease is well defined, it remains unclear why nigral dopaminergic neurons degenerate and die.. Most PD cases are idiopathic, but there are rare familial cases. Mutations in five genes are known to unambiguously cause monogenic familial PD: α-synuclein, parkin, DJ-1, PTEN-induced kinase 1 (PINK1), and leucine-rich repeat kinase 2 (LRRK2). These key molecular players are proteins of seemingly diverse function, but with potentially important roles in mitochondrial maintenance and function. Cell and animal-based genetic models have provided indispensable tools for understanding the molecular basis of PD, and have provided additional evidence implicating mitochondrial dysfunction as a primary pathogenic pathway leading to the demise of dopaminergic neurons in PD.. Here, we critically discuss the evidence for mitochondrial dysfunction in genetic animal models of PD, and evaluate whether abnormal mitochondrial function represents a cause or consequence of disease pathogenesis.. Mitochondria may represent a potential target for the development of disease-modifying therapies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genes, Dominant; Genes, Recessive; Humans; Intracellular Signaling Peptides and Proteins; Mitochondria; Parkinson Disease; Protein Kinases; Protein Serine-Threonine Kinases; Protein Transport; Signal Transduction; Ubiquitin-Protein Ligases

Multiple system atrophy (MSA) is a sporadic adult-onset neurodegenerative disorder clinically characterized by a variable combination of dysautonomia, levodopa-unresponsive parkinsonian and cerebellar symptoms. Neurodegeneration in MSA occurs in the substantia nigra, putamen, inferior olive, pontine and brainstem nuclei, as well as intermediolateral cell column of the spinal cord. MSA is recognized as a synucleinopathy due to the accumulation of insoluble alpha-synuclein in oligodendroglial cytoplasmic inclusions. Several animal models have been developed in order to reproduce various clinical and pathological features of MSA. Using "double toxin-double lesion" or "single toxin-double lesion", neurotoxin-based models were designed in rats, mice and non-human primates to reproduce the neuropathology of MSA in the nigrostriatal system while gene-based models were developed in mice to reproduce the accumulation of insoluble alpha-synuclein in oligodendrocytes. Both approaches have then been merged to create optimized, dual-hit models. This review describes the different animal models of MSA, their respective advantages and limitations and their usefulness to decipher the pathophysiology of MSA then to define efficient symptomatic and disease-modifying therapies. This article is part of a Special Issue entitled: Neuroscience Disease Models.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Multiple System Atrophy; Nerve Degeneration; Neurotoxins; Substantia Nigra

Both genetic and environmental factors trigger risks of and protection from Parkinson's disease, the second most common neurodegenerative syndrome, but possible inter-relationships between these risk and protection processes were not yet explored. By examining gene expression changes in the brains of mice under multiple treatments that increase or attenuate PD symptoms we detected underlying disease and protection-associated genes and pathways. In search for potential links between these different genes and pathways, we conducted meta-analysis on 131 brain region transcriptomes from mice over-expressing native or mutated α-synuclein (SNCA) with or without the protective HSP70 chaperone, or exposed to the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), with or without the protective acetylcholinesterase (AChE-R) variant. All these models showed shared risk-inducible and protection-suppressible transcript modifications. Self-organized map (SOM) classification revealed risk- and protection-associated alterations in nuclear and mitochondrial metal ion-regulated transcripts, respectively; Gene Ontology based analysis validated these pathways. To complement this approach, and identify potential outcome damages, we further searched for shared functional enrichments in the lists of genes detected in young SNCA mutant or in old SNCA mutants and MPTP-exposed mice. This post-hoc functional analysis identified early-onset changes in Parkinsonian, immune and alternative splicing pathways which shifted into late-onset or exposure-associated NFkB-mediated neuro-inflammation. Our study suggests metal ions-mediated cross-talk between nuclear and mitochondrial pathways by both environmental and genetic risk and protective factors involved in Parkinson's disease, which eventually culminates in neuro-inflammation. Together, these findings offer new insights and novel targets for therapeutic interference with the gene-environment interactions underlying sporadic PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Brain; Databases, Bibliographic; Disease Models, Animal; Gene Expression; Gene-Environment Interaction; HSP72 Heat-Shock Proteins; Humans; Intermediate Filament Proteins; Mice; Microarray Analysis; Mitochondria; Models, Biological; Parkinson Disease

Parkinson's disease is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. While sporadic in the majority of cases, PD-linked dominant mutations in the α-synuclein and LRRK-2 genes, and recessive mutations in the parkin, DJ-1 and PINK-1 genes have been identified in PD families in recent years. In this review we describe viral animal models for PD, i.e. models that are based on PD-associated mutations, and have been generated by viral delivery of the respective disease genes to the substantia nigra of rodents and non-human primates. To date, viral PD models comprise α-synuclein and LRRK-2-based overexpression models, as well as models that mimic parkin loss of function by overexpression of the parkin substrates Pael-R, CDCrel-1, p38/JTV or synphilin-1. These viral models provide valuable insights into Parkinson disease mechanisms, help to identify therapeutic targets and may contribute to the development of therapeutic approaches.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Carrier Proteins; Cell Cycle Proteins; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Nerve Tissue Proteins; p38 Mitogen-Activated Protein Kinases; Parkinson Disease; Protein Serine-Threonine Kinases; Receptors, G-Protein-Coupled; Septins; Ubiquitin-Protein Ligases; Viruses

The non-motor symptoms (NMS) of Parkinson's disease (PD) occur in roughly 90% of patients, have a profound negative impact on their quality of life, and often go undiagnosed. NMS typically involve many functional systems, and include sleep disturbances, neuropsychiatric and cognitive deficits, and autonomic and sensory dysfunction. The development and use of animal models have provided valuable insight into the classical motor symptoms of PD over the past few decades. Toxin-induced models provide a suitable approach to study aspects of the disease that derive from the loss of nigrostriatal dopaminergic neurons, a cardinal feature of PD. This also includes some NMS, primarily cognitive dysfunction. However, several NMS poorly respond to dopaminergic treatments, suggesting that they may be due to other pathologies. Recently developed genetic models of PD are providing new ways to model these NMS and identify their mechanisms. This review summarizes the current available literature on the ability of both toxin-induced and genetically-based animal models to reproduce the NMS of PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Hydroxydopamines; MPTP Poisoning; Neurotoxins; Parkinson Disease; Parkinson Disease, Secondary; Risk Factors; Rotenone; Uncoupling Agents

Animal models of Parkinson's disease (PD) have been widely used in the past four decades to investigate the pathogenesis and pathophysiology of this neurodegenerative disorder. These models have been classically based on the systemic or local (intracerebral) administration of neutoxins that are able to replicate most of the pathological and phenotypic features of PD in mammals (i.e. rodents or primates). In the last decade, the advent of the 'genetic era' of PD has provided a phenomenal enrichment of the research possibilities in this field, with the development of various mammalian (mice and, more recently, rats) and non-mammalian transgenic models that replicate most of the disease-causing mutations identified for monogenic forms of familial PD. Both toxic and transgenic classes of animal PD models have their own specificities and limitations, which must be carefully taken into consideration when choosing the model to be used. If a substantial and reproducible nigrostriatal lesion is required (e.g. for testing therapeutic interventions aimed at counteracting PD-related cell death), a classic toxic model such as one based on the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine or 6-hydroxydopamine will adequately serve the purpose. On the other hand, if selected molecular mechanisms of PD pathogenesis must be investigated, transgenic models will offer invaluable insights. Therefore, until the 'perfect' model is developed, indications to use one model or another will depend on the specific objectives that are being pursued.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Dopamine Agents; Herbicides; Humans; Neurotoxins; Oxidopamine; Paraquat; Parkinson Disease; Parkinson Disease, Secondary; Sympatholytics

Heterozygous mutations in the glucocerebrosidase gene (GBA1) are associated with increased risk for α-synuclein aggregation disorders ('synucleinopathies'), which include Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Homozygous GBA1 mutations lead to reduced GBA1 lysosomal activity underlying three variants of Gaucher disease (GD). Despite the wealth of clinical and genetic evidence supporting the association between mutant genotypes and synucleinopathy risk, the precise mechanisms by which GBA1 mutations lead to PD and DLB remain unclear. Here, we summarize recent findings that highlight the complexity of this pathogenetic link. In neural cells, both gain and loss of function mechanisms, as conferred by mutant GBA1 expression and activity loss, respectively, seem to promote aberrant α-synuclein processing. In addition, we draw attention to recent insights gleaned from GD animal models regarding axonal pathology, brain inflammation and memory dysfunction. From a translational perspective, we discuss the concepts of neural enzyme replacement therapy and pharmacological agents as potential treatment strategies for GBA1-associated synucleinopathies. Finally, we touch on the issue whether aberrant α-synuclein species may coregulate GBA1 activity in the vertebrate brain, thereby providing a reverse link, i.e., between an important synucleinopathy risk factor and the enzyme's lysosomal function. In summary, several leads connecting GBA1 mutations with α-synuclein misprocessing have emerged as potential targets for the treatment of GBA1-related synucleinopathies, and possibly, for non-GBA1-associated neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Gaucher Disease; Gene Expression Regulation; Glucosylceramidase; Humans; Mice; Mutation

Identification of mutations that cause rare familial forms of Parkinson's disease (PD) and subsequent studies of genetic risk factors for sporadic PD have led to an improved understanding of the pathological mechanisms that may cause nonfamilial PD. In particular, genetic and pathological studies strongly suggest that alpha-synuclein, albeit very rarely mutated in PD patients, plays a critical role in the vast majority of individuals with the sporadic form of the disease. We have extensively characterized a mouse model over-expressing full-length, human, wild-type alpha-synuclein under the Thy-1 promoter. We have also shown that this model reproduces many features of sporadic PD, including progressive changes in dopamine release and striatal content, alpha-synuclein pathology, deficits in motor and nonmotor functions that are affected in pre-manifest and manifest phases of PD, inflammation, and biochemical and molecular changes similar to those observed in PD. Preclinical studies have already demonstrated improvement with promising new drugs in this model, which provides an opportunity to test novel neuroprotective strategies during different phases of the disorder using endpoint measures with high power to detect drug effects.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Disease Progression; Humans; Mice; Mice, Neurologic Mutants; Parkinson Disease; Promoter Regions, Genetic

Activity-dependent modifications in synaptic efficacy, such as long-term depression (LTD) and long-term potentiation (LTP), represent key cellular substrates for adaptive motor control and procedural memory. The impairment of these two forms of synaptic plasticity in the nucleus striatum could account for the onset and the progression of motor and cognitive symptoms of Parkinson's disease (PD), characterized by the massive degeneration of dopaminergic neurons. In fact, both LTD and LTP are peculiarly controlled and modulated by dopaminergic transmission coming from nigrostriatal terminals. Changes in corticostriatal and nigrostriatal neuronal excitability may influence profoundly the threshold for the induction of synaptic plasticity, and changes in striatal synaptic transmission efficacy are supposed to play a role in the occurrence of PD symptoms. Understanding of these maladaptive forms of synaptic plasticity has mostly come from the analysis of experimental animal models of PD. A series of cellular and synaptic alterations occur in the striatum of experimental parkinsonism in response to the massive dopaminergic loss. In particular, dysfunctions in trafficking and subunit composition of glutamatergic NMDA receptors on striatal efferent neurons contribute to the clinical features of the experimental parkinsonism. Interestingly, it has become increasingly evident that in striatal spiny neurons, the correct assembly of NMDA receptor complex at the postsynaptic site is a major player in early phases of PD, and it is sensitive to distinct degrees of DA denervation. The molecular defects at the basis of PD progression may be not confined just at the postsynaptic neuron: accumulating evidences have recently shown that the genes linked to PD play a critical role at the presynaptic site. DA release into the synaptic cleft relies on a proper presynaptic vesicular transport; impairment of SV trafficking, modification of DA flow, and altered presynaptic plasticity have been described in several PD animal models. Furthermore, an impaired DA turnover has been described in presymptomatic PD patients. Thus, given the pathological events occurring precociously at the synapses of PD patients, post- and presynaptic sites may represent an adequate target for early therapeutic intervention.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Long-Term Potentiation; Mice; Mutation; Nerve Degeneration; Neuronal Plasticity; Parkinson Disease; Protein Serine-Threonine Kinases; Receptors, N-Methyl-D-Aspartate; Synapses; Synaptic Transmission; Transport Vesicles

α-Synuclein is a presynaptic neuronal protein that is linked genetically and neuropathologically to Parkinson's disease (PD). α-Synuclein may contribute to PD pathogenesis in a number of ways, but it is generally thought that its aberrant soluble oligomeric conformations, termed protofibrils, are the toxic species that mediate disruption of cellular homeostasis and neuronal death, through effects on various intracellular targets, including synaptic function. Furthermore, secreted α-synuclein may exert deleterious effects on neighboring cells, including seeding of aggregation, thus possibly contributing to disease propagation. Although the extent to which α-synuclein is involved in all cases of PD is not clear, targeting the toxic functions conferred by this protein when it is dysregulated may lead to novel therapeutic strategies not only in PD, but also in other neurodegenerative conditions, termed synucleinopathies.

Topics: alpha-Synuclein; Animals; Biomarkers; Cell Nucleus; Cytoskeleton; Disease Models, Animal; Endoplasmic Reticulum; Golgi Apparatus; Humans; Mitochondria; Oxidative Stress; Parkinson Disease; Protein Modification, Translational; Proteolysis

Although researchers are pursuing "disease modifying" medications to slow or stop Parkinson's disease (PD) progression, a myriad of agents with protective properties in cell cultures and animal models have yielded few treatments in clinical practice. Developing safe and effective treatments with disease-modifying/neuroprotective mechanisms of action and identifying patients in the pre-motor phase will be a challenge. The implication of tyrosine hydroxylase (TH), the enzyme that catalyzes the formation of L-3,4-dihydroxyphenylalanine, in the pathogenesis of PD at different levels makes it a promising candidate for developing efficient treatment based on correcting or bypassing the enzyme deficiency. TH is also the key enzyme for immunorreactivity in PD models and is used to assess the efficacy of novel disease-modifying medications. PD animal models are genetic: alpha-synuclein models, parkin (PINK 1 and DJ1) and leucine-rich repeat kinase 2 or pharmacological and neurotoxic: reserpine, 6-hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine, rotenone, paraquat/maneb, and trichloroethylene. This review is focused on the state of art of PD models, the relationship with TH, and potential neuroprotective agents to treat PD. The latter include gene therapy, transplantation, erythropoietin, natural phenolic compounds, doxycycline, ethyl pyruvate, 9-methyl-beta-carboline, vascular endothelial growth factor, simvastatin, zonisamide, modafinil, melatonin, cannabinoids, rottlerin, fluoxetine, paroxetine, coenzyme Q10, N-acetylcysteine and vaccines like Bacille Calmette-Guerin, with different proposed mechanisms of action. Also of note is the link between hypovitaminosis D and neurodegeneration opening new perspectives in research with TH genes and PD models treated with vitamin D. Translational scientists can contribute to a better understanding of the pathogenesis of PD and lead to more effective treatments.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Humans; Neuroprotective Agents; Parkinson Disease; Tyrosine 3-Monooxygenase

The etiology of Parkinson's disease (PD) is attributed to both environmental and genetic factors. The development of PD reportedly involves mitochondrial impairment, oxidative stress, α-synuclein aggregation, dysfunctional protein degradation, glutamate toxicity, calcium overloading, inflammation and loss of neurotrophic factors. Based on a link between mitochondrial dysfunction and pesticide exposure, many laboratories, including ours, have recently developed parkinsonian models by utilization of rotenone, a well-known mitochondrial complex I inhibitor. Rotenone models for PD appear to mimic most clinical features of idiopathic PD and recapitulate the slow and progressive loss of dopaminergic (DA) neurons and the Lewy body formation in the nigral-striatal system. Notably, potential human parkinsonian pathogenetic and pathophysiological mechanisms have been revealed through these models. In this review, we summarized various rotenone-based models for PD and discussed the implied etiology of and treatment for PD.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Humans; Lewy Bodies; Mitochondria; Oxidative Stress; Parkinson Disease; Proteolysis; Rotenone; Substantia Nigra

Parkinson's disease (PD) has for decades been considered a pure motor disorder and its cardinal motor symptoms have been attributed to the loss of dopaminergic (DAergic) neurons in the substantia nigra pars compacta and to nigral Lewy body pathology. However, there has more recently been a shift in the conceptualization of the disease, and its pathological features have now been recognized as involving several other areas of the brain and indeed even outside the central nervous system. There are a corresponding variety of intrinsic non-motor symptoms such as autonomic dysfunction, cognitive impairment, sleep disturbances and neuropsychiatric problems, which cannot be explained exclusively by nigral pathology. In this review, we will focus on cognitive impairment and affective symptoms in PD, and we will consider whether, and how, these deficits can best be modelled in rodent models of the disorder. As only a few of the non-motor symptoms respond to standard DA replacement therapies, the quest for a broader therapeutic approach remains a major research effort, and success in this area in particular will be strongly dependent on appropriate rodent models. In addition, better understanding of the different models, as well as the advantages and disadvantages of the available behavioural tasks, will result in better tools for evaluating new treatment strategies for PD patients suffering from these neuropsychological symptoms.

Topics: alpha-Synuclein; Animals; Cognition Disorders; Depression; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Mutation; Neuropsychological Tests; Parkinson Disease; Rats; Rats, Transgenic

Improvements in modelling Parkinson's disease in rodents contribute to the advancement of scientific knowledge and open innumerable pathways for the development of new therapeutic interventions. In a recent article in this journal, Decressac and co-workers present an interesting comparison between two classic 6-hydroxydopamine (6-OHDA) models and the more recently established rodent model of Parkinson's disease induced by over-expression of α-synuclein using adeno-associated viral vectors. As expected, injections of 6-OHDA result in extensive loss of dopamine associated with pronounced motor deficits. Interestingly, over-expression of α-synuclein in the substantia nigra pars compacta also results in a considerable loss of dopamine as well as motor impairments. Both the level of dopamine loss and the motor deficits seen after α-synuclein over-expression were similar in extent to that seen after intrastriatal injections of 6-OHDA, but the temporal profile of degeneration and the development of motor deficits were progressive, more closely mimicking the clinical condition. This commentary offers further insights into the differences between these two rodent models, and asks how well they each replicate idiopathic PD. In addition, the translational relevance, reliability, and predictive value of this more recently developed AAV α-synuclein model are considered.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genetic Vectors; Humans; Oxidopamine; Parkinson Disease; Parkinson Disease, Secondary; Rats

Cardiovascular autonomic dysfunction is a common non-motor symptom associated with synucleinopathies such as Parkinson's disease (PD). Several recent clinical studies indicate that cardiovascular autonomic impairments including orthostatic hypotension and sympathetic denervation may precede the development of the cardinal motor symptoms in PD, making cardiovascular dysfunction an attractive target for the development of biomarkers for early detection and potential neuroprotective strategies for PD. However, the pathologic mechanisms underlying cardiovascular dysfunction as well as many of the non-motor symptoms in PD remain unknown. This is likely due, in part, to an initial under-appreciation of PD as a systemic disorder as well as limited research in cardiovascular dysfunction in animal models of PD. Here, we highlight studies that have investigated cardiovascular dysfunction in rodent models of PD and the potential usefulness of genetic mouse models of PD for this endeavor.

Topics: alpha-Synuclein; Animals; Autonomic Nervous System Diseases; Blood Pressure; Cardiovascular Diseases; Disease Models, Animal; Heart Rate; Humans; Parkinson Disease

Synucleopathies are neurodegenerative disorders characterized by abnormal accumulation of alpha-synuclein, most often in neurons. Familial forms are due to mutations or multiplications of the gene encoding for alpha-synuclein but most synucleopathies occur sporadically. They include Parkinson's disease (PD) and dementia with Lewy Bodies (DLB), which are both linked to cognitive decline. In DLB, dementia dominates the symptoms whereas in PD, subtle cognitive deficits are frequent and may appear even before motor symptoms, but only a fraction of patients develop severe dementia-type cognitive deficits. Several lines of mice were developed to model human synucleopathies by over-expressing the wild type or the mutated human alpha-synuclein under a variety of promoters. In addition, mice lacking alpha-synuclein have been used to determine the role of this protein in cognitive function. This chapter will review cognitive alterations observed in these models and discuss how they may help understand the various forms and stages of cognitive deficits observed in patients with synucleopathies.

Topics: alpha-Synuclein; Animals; Calcium-Calmodulin-Dependent Protein Kinases; Cognition Disorders; Disease Models, Animal; Humans; Mice; Parkinson Disease; Prions; Thy-1 Antigens

Parkinson's disease (PD) is a major age-related neurodegenerative disorder characterized by a massive and specific loss of dopaminergic neurons of the substantia nigra pars compacta. The cellular alterations are clinically translated into an invalidating movement disability associated to three canonical symptoms that are bradykinesia, resting tremor and rigidity. The exact causes of this neuronal loss are unknown, but a network of evidences indicates a major contribution of orchestrated cell death processes, also known as apoptosis. Apoptotic cell death is a normal process, the alteration of which triggers several pathologies including cancer and neurodegenerative disorders. Exhaustive work has been done to delineate the cellular mechanisms responsible for the exacerbated cell death of dopaminergic neurons observed in PD. Overall, the oncogene p53 has been identified as a key effector protein. This review will focus on the clues linking p53 to the etiology of PD and the evidences that this protein may be at the center of multiple signaling cascades not only altered by mutations of various proteins responsible for familial cases of PD but also on more general sporadic cases of this devastating disease.

Topics: alpha-Synuclein; Animals; Apoptosis; Autophagy; Disease Models, Animal; Genes, Recessive; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Oncogene Proteins; Parkinson Disease; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Tumor Suppressor Protein p53; Ubiquitin-Protein Ligases

The past decade in Parkinson's disease (PD) research has been punctuated by numerous advances in understanding genetic factors that contribute to the disease. Common to most of the genetic models of Parkinsonian neurodegeneration are pathologic mechanisms of mitochondrial dysfunction, secretory vesicle dysfunction and oxidative stress that likely trigger common cell death mechanisms. Whereas presynaptic function is implicated in the function/dysfunction of α-synuclein, the first gene shown to contribute to PD, synaptic function has not comprised a major focus in most other genetic models. However, recent advances in understanding the impact of mutations in parkin and LRRK2 have also yielded insights into synaptic dysfunction as a possible early pathogenic mechanism. Autophagy is a common neuronal response in each of these genetic models of PD, participating in the clearance of protein aggregates and injured mitochondria. However, the potential consequences of autophagy upregulation on synaptic structure and function remain unknown. In this review, we discuss the evidence that supports a role for synaptic dysfunction in the neurodegenerative cascade in PD, and highlight unresolved questions concerning a potential role for autophagy in either pathological or compensatory synaptic remodeling. This article is part of a Special Issue entitled "Autophagy and protein degradation in neurological diseases."

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mice, Mutant Strains; Mutation; Parkinson Disease; Protein Serine-Threonine Kinases; Synapses; Ubiquitin-Protein Ligases

The involvement of the spinal cord in parkinsonism is becoming more and more evident based on human autopsies and on experimental models, obtained using specific neurotoxins or genetic manipulations. Besides Parkinson disease, other degenerative disorders characterized by parkinsonism, involve the spinal cord, and multiple neurotransmitters, apart dopamine, are altered in parkinsonism, also in their spinal projections. In the present review we discuss spinal cord pathology of different genetic or toxic experimental models of parkinsonism, as well as the neuropathological reports from autoptic cases of sporadic Parkinson disease and of other neurodegenerative conditions, overlapping with parkinsonism. Furthermore, anatomical distribution of alpha-synuclein in the spinal cord and coeruleo-spinal projections are reviewed, at the light of their possible involvement in spinal neurons degeneration. All these evidences call for an anatomical stemmed novel approach to understand specific features of parkinsonism, which might be due to such an involvement of the spinal cord. Moreover they suggest a common neurodegenerative process, underlying distinct neurodegenerative disorders, to which spinal neurons could be the more sensible.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Nerve Degeneration; Neurons; Parkinsonian Disorders; Spinal Cord

As a prototypic neurodegenerative disorder Parkinson's disease (PD) is characterized by the progressive loss of specific neuronal subpopulations leading to a late-onset movement disorder. Based on familial forms of PD, to date a significant number of genes were identified that allowed first insight into the molecular pathogenesis of this common movement disorder. These pathways include impaired protein degradation and subsequent aggregation within neuronal cells and impaired mitochondrial function followed by energy depletion due to oxidative stress leading to cell death. The respective disease models were supported by pathoanatomical and biochemical findings in brains of sporadic PD patients without apparent genetic contribution to pathogenesis. Indeed recent genetic and epidemiological studies hint to a complex interplay of genetic susceptibility factors and environmental risk factors to converge to processes of pathological protein accumulation and mitochondrial damage that trigger neurodegeneration in PD. Therefore large-scale geneticoepidemiological studies combining genetic whole genome approaches with a detailed ascertainment of environmental exposures are expected to provide important clues to decipher the complexity of neurodegeneration of this most frequent neurodegenerative movement disorder.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Environment; Genetic Predisposition to Disease; Humans; Mitochondrial Diseases; Mutation; Parkinson Disease; Risk Factors; Ubiquitin-Protein Ligases

Dominantly inherited mutations in leucine-rich repeat kinase 2 are the most common cause of familial Parkinson's disease. Understanding leucine-rich repeat kinase 2 biology and pathophysiology is central to the elucidation of Parkinson's disease etiology and development of disease intervention. Recently, a number of genetic mouse models of leucine-rich repeat kinase 2 have been reported utilizing different genetic approaches. Some similarities in Parkinson's disease-related pathology emerge in these genetic models despite lack of substantial neuropathology and clinical syndromes of Parkinson's disease. The systematic characterization of these models has begun to shed light on leucine-rich repeat kinase 2 biology and pathophysiology and is expected to offer the identification and validation of drug targets. In this review, we summarize the progress of genetic leucine-rich repeat kinase 2 mouse models and discuss their utility in understanding much needed knowledge regarding early-stage (presymptomatic) disease progression, identifying drug targets, and exploring the potential to aid compound screening focused on inhibitors of kinase activity of leucine-rich repeat kinase 2.

Topics: alpha-Synuclein; Animals; Antiparasitic Agents; Disease Models, Animal; Gene Expression Regulation; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mice, Transgenic; Mutation; Nerve Degeneration; Neuroglia; Parkinson Disease; Protein Serine-Threonine Kinases; tau Proteins

BAC (bacterial artificial chromosome)-transgenic mice expressing a transgene from an entire genomic locus under the control of the native promoter offer the opportunity to generate more accurate genetic models of human disease. The present review discusses results of recent studies investigating PD (Parkinson's disease) and tauopathies using BAC-transgenic mice carrying either the LRRK2 (leucine-rich repeat kinase 2), α-synuclein (SNCA) or MAPT (microtubule-associated protein tau) genes. In all lines, expression of the WT (wild-type) gene resulted in physiologically relevant protein expression. The effect of expressing the mutant form of a gene varied depending on the mouse strain or the particular disease mutation used, although it was common to see either neurochemical or behavioural differences in these animals. Overall, BAC technology offers an exciting opportunity to generate a wide range of new animal models of human-disease states.

Topics: alpha-Synuclein; Animals; Chromosomes, Artificial, Bacterial; Disease Models, Animal; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mice, Transgenic; Mutation; Parkinson Disease; Protein Serine-Threonine Kinases; tau Proteins

Multiple system atrophy (MSA) is a neurodegenerative disease involving motor abnormalities that include akinesia, rigidity and postural instability. While improved diagnostic criteria have aided the accurate diagnosis of MSA, our understanding of the neuropathological aspects underlying MSA was bolstered by the identification of α-synuclein (α-syn) as the primary constituent of the abnormal protein aggregates observed in the brains of MSA patients. The generation of transgenic animal models of MSA coupled with an increasing understanding of the biochemical structure and function of α-syn has highlighted a number of key pathological pathways thought to underlie the neurodegeneration observed in MSA. This review summarizes key findings in the field, discusses current areas of debate, and describes current experimental approaches towards disease-modifying therapies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Humans; Multiple System Atrophy; Oligodendroglia

The nematode Caenorhabditis elegans has a very well-defined and genetically tractable nervous system which offers an effective model to explore basic mechanistic pathways that might be underpin complex human neurological diseases. Here, the role C. elegans is playing in understanding two neurodegenerative conditions, Parkinson's and Alzheimer's disease (AD), and a complex neurological condition, autism, is used as an exemplar of the utility of this model system. C. elegans is an imperfect model of Parkinson's disease because it lacks orthologues of the human disease-related genes PARK1 and LRRK2 which are linked to the autosomal dominant form of this disease. Despite this fact, the nematode is a good model because it allows transgenic expression of these human genes and the study of the impact on dopaminergic neurons in several genetic backgrounds and environmental conditions. For AD, C. elegans has orthologues of the amyloid precursor protein and both human presenilins, PS1 and PS2. In addition, many of the neurotoxic properties linked with Aβ amyloid and tau peptides can be studied in the nematode. Autism spectrum disorder is a complex neurodevelopmental disorder characterised by impairments in human social interaction, difficulties in communication, and restrictive and repetitive behaviours. Establishing C. elegans as a model for this complex behavioural disorder is difficult; however, abnormalities in neuronal synaptic communication are implicated in the aetiology of the disorder. Numerous studies have associated autism with mutations in several genes involved in excitatory and inhibitory synapses in the mammalian brain, including neuroligin, neurexin and shank, for which there are C. elegans orthologues. Thus, several molecular pathways and behavioural phenotypes in C. elegans have been related to autism. In general, the nematode offers a series of advantages that combined with knowledge from other animal models and human research, provides a powerful complementary experimental approach for understanding the molecular mechanisms and underlying aetiology of complex neurological diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Child; Child Development Disorders, Pervasive; Disease Models, Animal; Dopaminergic Neurons; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Nerve Degeneration; Parkinson Disease; Presenilins; Protein Serine-Threonine Kinases; Synapses

Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS) are the second and third most common human adult-onset neurodegenerative diseases, respectively, after Alzheimer's disease. They are characterized by prominent age-related neurodegeneration in selectively vulnerable neural systems. Some forms of PD and ALS are inherited, and genes causing these diseases have been identified. Morphological, biochemical, and genetic, as well as cell and animal model, studies reveal that mitochondria could have a role in this neurodegeneration. The functions and properties of mitochondria might render subsets of selectively vulnerable neurons intrinsically susceptible to cellular aging and stress and overlying genetic variations. In PD, mutations in putative mitochondrial proteins have been identified and mitochondrial DNA mutations have been found in neurons in the substantia nigra. In ALS, changes occur in mitochondrial respiratory chain enzymes and mitochondrial cell death proteins. Transgenic mouse models of human neurodegenerative disease are beginning to reveal possible principles governing the biology of selective neuronal vulnerability that implicate mitochondria and the mitochondrial permeability transition pore. This review will present how mitochondrial pathobiology might contribute to neurodegeneration in PD and ALS and could serve as a target for drug therapy.

Topics: alpha-Synuclein; Amyotrophic Lateral Sclerosis; Animals; Disease Models, Animal; DNA, Mitochondrial; Humans; Mitochondria; Mitochondrial Diseases; Models, Biological; Mutation; Parkinson Disease; Protein Kinases; Ubiquitin Thiolesterase

The classical animal models of Parkinson's disease (PD) rely on the use of neurotoxins, including 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 6-hydroxydopamine and, more recently, the agricultural chemicals paraquat and rotenone, to deplete dopamine (DA). These neurotoxins elicit motor deficits in different animal species although MPTP fails to induce a significant dopaminergic neurodegeneration in rats. In the attempt to better reproduce the key features of PD, in particular the progressive nature of neurodegeneration, alternative PD models have been developed, based on the genetic and neuropathological links between -synuclein ( -syn) and PD. In vivo microdialysis was used to investigate extracellular striatal DA dynamics in MPTP- and -syn-generated rodent models of PD. Acute and sub-acute MPTP intoxication of mice both induce prolonged release of striatal DA. Such DA release may be considered the first step in MPTP-induced striatal DA depletion and nigral neuron death, mainly through reactive oxygen species generation. Although MPTP induces DA reduction, neurochemical and motor recovery starts immediately after the end of treatment, suggesting that compensatory mechanisms are activated. Thus, the MPTP mouse model of PD may be unsuitable for closely reproducing the features of the human disease and predicting potential long-term therapeutic effects, in terms of both striatal extracellular DA and behavioral outcome. In contrast, the -syn-generated rat model of PD does not suffer from a massive release of striatal DA during induction of the nigral lesion, but rather is characterized by a prolonged reduction in baseline DA and nicotine-induced increases in dialysate DA levels. These results are suggestive of a stable nigrostriatal lesion with a lack of dopaminergic neurochemical recovery. The -syn rat model thus reproduces the initial stage and slow development of PD, with a time-dependent impairment in motor function. This article will describe the above experimental PD models and demonstrate the utility of microdialysis for their characterization.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Humans; Mice; Mice, Transgenic; Microdialysis; Neurotoxins; Parkinson Disease; Parkinsonian Disorders; Rats; Rats, Transgenic

A better understanding of the molecular and cellular determinants that influence the pathology of Parkinson's disease (PD) is essential for developing effective diagnostic, preventative and therapeutic strategies to treat this devastating disease. A number of post-translational modifications to alpha-syn are present within the Lewy bodies in the brains of affected patients and transgenic models of PD and related disorders. However, whether disease-associated alpha-syn post-translational modifications promote or inhibit alpha-syn aggregation and neurotoxicity in vivo remains unknown. Herein, we summarize and discuss the major disease-associated post-translational modifications (phosphorylation, truncation and ubiquitination) and present our current understanding of the effect of these modifications on alpha-syn aggregation and toxicity. Elucidating the molecular mechanisms underlying post-translation modifications of alpha-syn and the consequences of such modifications on the biochemical, structural, aggregation and toxic properties of the protein is essential for unravelling the molecular basis of its function(s) in health and disease. Furthermore, the identification of the natural enzymes involved in regulating the post-translational modifications of alpha-synuclein will yield novel and more tractable therapeutic targets to treat PD and related synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drosophila; Humans; Lewy Bodies; Parkinson Disease; Phosphorylation; Protein Processing, Post-Translational; Rats; Ubiquitination

The identification of several mutations causing familial forms of Parkinson's disease (PD) has led to the creation of multiple lines of mice expressing similar genetic alterations. These models present a unique opportunity for understanding pathophysiological mechanisms leading to PD in a mammalian brain and provide models that are suitable for the preclinical testing of new therapies. Different lines of mice recapitulate the symptoms and pathological features of PD to various extents. This chapter examines their respective advantages and highlights some of the key findings that have already emerged from the analysis of these new models of PD.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain Chemistry; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Catecholamines; Cricetinae; Disease Models, Animal; Dopamine; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Parkinson Disease; Platelet-Derived Growth Factor; Prions; Promoter Regions, Genetic; Protein Serine-Threonine Kinases; Psychomotor Performance; Tyrosine 3-Monooxygenase

The discovery of the role of α-synuclein in the pathogenesis of Parkinson's disease (PD) has opened new possibilities for the development of more authentic models of Parkinson's disease. Recombinant adeno-associated virus (AAV) and lentivirus (LV) vectors are efficient tools for expression of genes locally in subsets of neurons in the brain and can be used to express human wild-type or mutated α-synuclein selectively in midbrain dopamine neurons. Using this approach, it is possible to trigger extensive PD-like cellular and axonal pathologies in the nigrostriatal projection, involving abnormal protein aggregation, neuronal dysfunction, and cell death that develop progressively over time. Targeted overexpression of human α-synuclein in midbrain dopamine neurons, using AAV vectors, reproduces many of the characteristic features of the human disease and provides, for the first time, a model of progressive PD that can be applied to both rodents and primates.

Topics: alpha-Synuclein; Animals; Axons; Cell Death; Dependovirus; Disease Models, Animal; Disease Progression; Dopamine; Genetic Vectors; Humans; Inflammation; Lentivirus; Neurons; Parkinson Disease; Protein Processing, Post-Translational; Rats

Non-human primate (NHP) models of Parkinson's disease (PD) have been essential in understanding the pathophysiology and neural mechanisms underlying PD. The most common toxin employed, MPTP, produces a parkinsonian phenotype in NHPs that is very similar to human PD with excellent response to dopaminergic drugs and development of long-term motor complications. Over the past 25 years, MPTP-lesioned NHP models, using several species and a variety of MPTP administration regimens, have been used to understand disease pathophysiology, investigate several stages of the disease progression, from pre-symptomatic to advanced with motor complications, and apply knowledge gained to develop potential therapeutics. Many treatments in common use in PD patients were developed on the basis of studies in the MPTP model, in particular dopamine agonists, amantadine, and targeting the subthalamic nucleus for surgical treatment of PD. Continued development of novel therapies for PD will require improving methods of evaluating symptoms in NHPs to ease translation from NHP to patients with homogenized scales and endpoints. In addition, recent studies into non-motor symptoms of PD, especially in response to chronic treatment, is expanding the usefulness and impact of MPTP-lesioned NHP models. Despite these obvious successes, limitations still exist in the model, particularly when considering underlying mechanisms of disease progression; thus, it appears difficult to reliably use acute toxin administration to replicate a chronic progressive disorder and provide consistent evidence of Lewy-like bodies.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Basal Ganglia; Cognition Disorders; Disease Models, Animal; Dopamine; Drug Discovery; Endpoint Determination; Humans; Levodopa; Movement; MPTP Poisoning; Neurons; Neuroprotective Agents; Parkinson Disease, Secondary; Primates; Psychoses, Substance-Induced; Sleep Wake Disorders

Many groups have generated alpha-synuclein (alpha-syn) transgenic (tg) mice as a rodent model for human synucleinopathies, including Parkinson's disease and dementia with Lewy bodies (DLB). Indeed, some of the lines displayed limited evidence of neurodegeneration, such as alpha-syn deposits, compromised function of dopaminergic neurons, fibrillization of alpha-syn, and astrogliosis. However, none of them fully replicate the pathological features of synucleinopathies. To better understand the pathogenesis of the synucleinopathies and to develop new therapeutic strategies, improvement of the current version of alpha-syn tg mice may be required. We predict that beta-synuclein (beta-syn), the homologue of alpha-syn, might be a key molecule for this purpose. Although beta-syn is a neuroprotective molecule counteracting the alpha-syn pathology in tg mice, it was previously shown that both beta-syn and gamma-synuclein were associated with axonal pathology in the hippocampus of sporadic cases of Parkinson's disease and DLB. Furthermore, two missense mutations (P123H and V70M) of beta-syn were recently identified in DLB. These mutants of beta-syn were prone to aggregate in vitro and overexpression of these mutant beta-syn proteins in neuroblastoma cells resulted in enhanced lysosomal pathology. Taken together, these results suggest that a toxic gain of function of beta-syn might be involved in the pathogenesis of synucleinopathies. In this context, it is of considerable interest to determine if mutant beta-syn-overexpressing tg mice could exhibit neuropathological features distinct from those in conventional alpha-syn tg mice. Furthermore, it is expected that a bigenic mouse model for mutant beta-syn/alpha-syn might be characterized by a more accelerated phenotype of synucleinopathies.

Topics: alpha-Synuclein; Animals; beta-Synuclein; Brain; Disease Models, Animal; Genetic Predisposition to Disease; Humans; Lewy Bodies; Lewy Body Disease; Mice; Mutation, Missense; Parkinson Disease

The recent discovery of a number of genes involved in familial forms of Parkinson's disease (PD) has moved the use of model genetic organisms to the frontline. One avenue holding tremendous potential to find therapies against human diseases is the use of intact living systems where complex biological processes can be examined. Despite key differences that need to be taken into account when using invertebrate models such as Drosophila, there are many advantages offered by this system. The rapid generation time and the ability to easily generate transgenic animals together with the variety of genetic tools to control temporal and spatial expression of any given gene makes the fly model a very attractive system to study human neurodegenerative disorders. In this review, we analyze how the use of fruit flies has revealed to be an excellent tool providing valuable insights into the current understanding of the molecular mechanisms involved in the progression of PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Humans; Mitochondria; Oxidative Stress; Parkinson Disease; Protein Serine-Threonine Kinases; Serine Proteases; Superoxides; Ubiquitin-Protein Ligases

Nonclinical and clinical evidences have supported the view that accumulations of neurotoxic amyloid components initiate chain reactions of molecular and cellular pathologies, eventually leading to neuronal death and symptomatic onsets of neurodegenerative diseases. As this amyloid-triggered cascade is virtually composed of bidirectional causalities between upstream and downstream events, it is of critical significance to monitor all key processes, including amyloidosis, neuroinflammation, disrupted calcium homeostasis and impaired neurotransmissions, in living brains toward therapeutic regulations of the entire cascade. Positron emission tomography (PET) offers quantitative mapping of these alterations with the aid of multiple classes of radioprobes. Comparative PET assays of humans and animal models in conjunction with cognitive, biochemical and histopathological assessments have revealed toxic subspecies of amyloid beta peptide, tau proteins and microglia detectable by specific molecular probes. Dysregulated neurotransmissions are also capturable by PET techniques, while it should be noted that the accessibility of binding components to exogenous radioligands does not simply reflect their amounts but also is affected by their translocation, posttranslational modifications and interaction with endogenous ligands and other molecules. Clarification of these changes in target elements brings mechanistic insights into the molecular etiology of neuropsychiatric disorders.

Topics: Aging; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Positron-Emission Tomography; Receptors, GABA-A; tau Proteins; Translational Research, Biomedical

The involvement of alpha-synuclein in familial forms of Parkinson's disease suggests a potential causative role in the pathogenesis. We have explored the possibility of generating animal models of Parkinson's disease by overexpressing alpha-synuclein in the nigrostriatal pathway using viral vectors. Both lentiviral and adeno-associated vectors efficiently transduce dopaminergic neurons in the substantia nigra, and transgenic expression of alpha-synuclein leads to the progressive loss of neurons positive for dopaminergic markers, with the formation of intraneuronal alpha-synuclein aggregates. With a high tropism for nigral dopaminergic neurons, adeno-associated vectors allow for the monitoring of dopaminergic function using spontaneous and drug-induced behaviour. We propose that virus-based rodent alpha-synuclein models provide a valuable approach for the preclinical testing of therapeutics.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genetic Therapy; Genetic Vectors; Humans; Lentivirus; Parkinson Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized pathologically by the degeneration of nigrostriatal pathway dopaminergic neurons and other neuronal systems and the appearance of Lewy bodies that contain alpha-synuclein. PD is generally a sporadic disease, but a small proportion of cases have a clear genetic component. Mutations have been identified in six genes that clearly segregate with disease in rare families with PD. Transgenic, knockout, and virus-based models of disease have been developed in rodents to further understand how these genes contribute to the pathogenesis of PD. In general, these animal models recapitulate many key features of the disease, including derangements in dopaminergic synaptic transmission, selective neurodegeneration, neurochemical deficits, alpha-synuclein-positive neuropathology, and motor deficits. However, a genetic model with all or most of these pathogenic features has proved difficult to create. In this article, we discuss these mammalian genetic models of PD and what they have revealed about the cause and mechanisms of this disease.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Humans; Lewy Bodies; Mice; Parkinsonian Disorders; Rats; Ubiquitin-Protein Ligases

Studies of various animal models have made a substantial contribution to the recent progress in understanding of molecular and cellular bases of neurodegenerative disorders. Modelling of neurodegeneration by genetic alteration of laboratory animals became one of the most powerful tools of modern experimental neurology. The crucial event in pathogenesis of neurodegenerative diseases known as synucleinopathies is modification of alpha-synuclein metabolism caused by missense mutations, increased expression of the gene, or impaired degradation or intracellular compartmentalisation of the protein. Therefore, manipulations with expression of alpha-synuclein in laboratory animals were widely used for creating models of these diseases. In the present review we discuss strong and weak sides of such models, what has been already learned from studies of these animals and what types of models might be useful to further our knowledge about pathogenesis of different synucleinopathies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cell Compartmentation; Disease Models, Animal; Humans; Mice; Mutation, Missense; Neurodegenerative Diseases; Neurons; Oligodendroglia

Point mutations and genomic multiplications in the alpha-synuclein (alphaSYN) gene cause autosomal-dominant Parkinson's disease. Moreover, alphaSYN fibrils are the major component of Lewy bodies, the neuropathological hallmarks of Parkinson's disease and dementia with Lewy bodies as well as of glial cytoplasmic inclusions in multiple system atrophy. These diseases are collectively referred to as alpha-synucleinopathies. Cellular mechanisms regulating alphaSYN fibril formation and toxicity are intensely studied in vitro, and in cell culture and diverse animal models. Specific neuropathology was achieved in transgenic mouse models using several promoters to express human wild-type and mutant alphaSYN in brain regions affected by the various alpha-synucleinopathies. Somatodendritic accumulation of the transgenic alphaSYN with neuritic distortions was a common finding. The nigrostriatal dopaminergic projections were surprisingly resistant to alpha-synucleinopathy in transgenic mice, although they tended to be more vulnerable to neurotoxins. In a few mouse models, alphaSYN aggregated in an age-dependent manner into genuine fibrillar amyloid. Brain region selective alphaSYN neuropathology correlated with specific behavioral impairments, such as locomotor dysfunction and cognitive decline. Thus, the alphaSYN fibrillization process is tightly linked to neuropathology. The role and thus therapeutic potential of post-translational modifications (ubiquitinylation, oxidation, phosphorylation, truncation) and modifier genes on alphaSYN neuropathology can now be assessed in valid transgenic mouse models of alpha-synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Neurodegenerative Diseases

Mutations in alpha-synuclein were the first genetic defect linked to Parkinson's disease (PD). The relevance of alpha-synuclein to sporadic PD is strongly supported by the presence of alpha-synuclein aggregates in neurons of patients. This has prompted the development of numerous animal models based on alpha-synuclein overexpression, primarily through genetic methods in mice and viral transduction in rats. In mice, different promoters and transgenes lead to a wide variety of phenotypes accompanied by non-existent, late onset, or non-specific neurodegeneration. Rapid neurodegeneration, in contrast, is observed after viral transduction but is limited to the targeted region and does not mimic the broad pathology observed in the disease. Overall, each model reproduces a subset of features of PD and can be used to identify therapeutic targets and test disease-modifying therapies. The predictive value of all models of the disease, however, remains speculative in the absence of effective neuroprotective treatments for PD in humans.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Genetic Vectors; Mice; Mice, Transgenic; Parkinson Disease; Rats

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Humans; Models, Animal; Nerve Degeneration; Parkinson Disease

Numerous evidences indicate that the phenotype of a neurodegenerative disease and its pathogenetic mechanism are only loosely linked. The phenotype is directly related to the topography of the lesions and is reproduced whatever the mechanism as soon as the same neurons are destroyed or deficient: the symptoms of Parkinson disease are mimicked by any destruction of the neurons of the substantia nigra, caused for instance by the toxin MPTP. This does not mean that idiopathic Parkinson disease is due to MPTP. In the same way, mouse lines such as Reeler, Weaver and Staggerer in which ataxia occurs spontaneously does not help to understand human ataxias: now that mutations responsible for these phenotypes have been identified, it appears that one is responsible for lissencephaly (mutation of the reelin gene) and the other two have no equivalent in man. Therapeutic attempts, however, rely on the understanding of the pathogenetic mechanisms. Introducing a mutated human transgene in the genome of an animal has, in many instances, significantly improved this understanding. Transgenic mice have proven useful in reproducing lesions seen in neurodegenerative disease such as the plaques of Alzheimer disease (in the APP mouse which has integrated the mutated gene of the amyloid protein precursor), the tau glial and neuronal accumulation (seen in cases of frontotemporal dementias due to tau mutation), the nuclear inclusions caused by CAG triplet expansion (seen in the mutation of Huntington disease and autosomal dominant spinocerebellar ataxias). These recent advances have fostered numerous therapeutic attempts. Transgenesis in drosophila and in the worm Caenorhabditis elegans have opened new possibilities in the screening of protein partners, modifier genes, and potential therapeutic molecules. However, it is also becoming clear that introducing a human mutated gene in an animal does not necessarily trigger pathogenetic cascades identical to those seen in the human disease. Human diseases have to be studied in parallel with their animal models to ensure that the model mimic at least a few original mechanisms, on which new therapeutics may be tested.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Ataxia; Caenorhabditis elegans; Dementia; Disease Models, Animal; Drosophila melanogaster; Gene Targeting; Genes, Recessive; Heredodegenerative Disorders, Nervous System; Humans; Lewy Body Disease; Mice; Mice, Knockout; Mice, Neurologic Mutants; Minisatellite Repeats; Neurodegenerative Diseases; Neurotoxins; Parkinsonian Disorders; Prion Diseases; Reelin Protein; Species Specificity; tau Proteins

Neurodegenerative disorders of the aging population affect over 5 million people in the US and Europe alone. The common feature is the progressive accumulation of misfolded proteins with the formation of toxic oligomers. Previous studies show that while in Alzheimer's disease (AD) misfolded amyloid-beta protein accumulates both in the intracellular and extracellular space, in Lewy body disease (LBD), Parkinson's disease (PD), Multiple System Atrophy (MSA), Fronto-Temporal dementia (FTD), prion diseases, amyotrophic lateral sclerosis (ALS) and trinucleotide repeat disorders (TNRD), the aggregated proteins accumulate in the plasma membrane and intracellularly. Protein misfolding and accumulation is the result of an altered balance between protein synthesis, aggregation rate and clearance. Based on these studies, considerable advances have been made in the past years in developing novel experimental models of neurodegenerative disorders. This has been in part driven by the identification of genetic mutations associated with familial forms of these conditions and gene polymorphisms associated with the more common sporadic variants of these diseases. Transgenic and knock out rodents and Drosophila as well as viral vector driven models of Alzheimer's disease (AD), PD, Huntington's disease (HD) and others have been developed, however the focus for this review will be on rodent models of AD, FTD, PD/LBD, and MSA. Promising therapeutic results have been obtained utilizing amyloid precursor protein (APP) transgenic (tg) models of AD to develop therapies including use of inhibitors of the APP-processing enzymes beta- and gamma-secretase as well as vaccine therapies.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Animals, Genetically Modified; Disease Models, Animal; Humans; Lewy Body Disease; Multiple System Atrophy; Neurodegenerative Diseases; Parkinson Disease; tau Proteins

Ideally, animal models of neurodegenerative diseases should reproduce the clinical manifestation of the disease and a selective neuronal loss. In this review we will take as an example Parkinson's disease because its pathophysiology is well known and the neuronal loss well characterized. Indeed, Parkinson's disease is characterized by a loss of some but not all dopaminergic neurons, a loss of some non dopaminergic neurons and alpha-synuclein positive inclusions resembling Lewy bodies. There are at least two ways to develop animal models of PD based on the etiology of the disease and consist in 1) reproducing in animals the mutations seen in inherited forms of PD; 2) intoxicating animals with putative environmental toxins causing PD. In this review we discuss the advantages and the drawbacks in term of neuroproction of the currently used models.

Topics: alpha-Synuclein; Animals; Brain; Cell Death; Disease Models, Animal; Dopamine; Humans; Lewy Bodies; Mutation; Neurons; Neuroprotective Agents; Neurotoxins; Parkinsonian Disorders

Since the discovery that mutations of alpha-synuclein (AS) gene are responsible for rare forms of familiar Parkinson's disease this synaptic protein attracted increased interest. AS is the main constituent of Lewy bodies. In spite the physiological function is still unclear there is an ongoing discussion if over-expression is already dangerous, or if toxicity is subjected to oligomers, protofibrilles or mature aggregates. The fact that the central hydrophobic part of AS is a constituent of amyloid plaques in Alzheimer patients and the finding that a majority of AD patients have Lewy bodies and Lewy neurites in specific brain areas, raised our interest in the possible contribution of AS to pathogenesis of AD. Beta-synuclein (betaS) a protein of the same gene family seems to be a naturally occurring anti aggregatory factor preventing AS aggregation in vitro and in vivo. The N-terminal amino acid sequence 1 to 15 is responsible for this effect. Based on this finding we synthesized a peptide library with different sequence variations. Several of these peptides displayed distinct neuroprotective activity in tissue culture models of neurodegeneration induced by oxidative stress or Abeta1-42. In spite these peptides have a short half-life, in vivo significant reduction in brain plaque load and improvement of behavioral deficits was demonstrated in an APP-tg mouse model after intranasal treatment for 2 months. KEGV, the shortest sequence was also active after intraperitoneal application. Neuroprotective data in tissue cultures and results from transgenic mice are some how in conflict because in vitro effects can not be explained by the antiaggregatory potential, but most likely by interaction of betaS derivates with anti-apoptotic PI3/Akt cell signaling or interference with anti-oxidative pathways (JNK/JIB). The possibility that such betaS derived peptidomimetics might act as neuroprotectants and at the same time prevent protein missfolding suggests possible therapeutic usefulness in different neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Neurodegenerative Diseases; Neuroprotective Agents; Peptide Library; Peptides

Despite the prevalence and severity of Parkinson's disease (PD), little is known about the molecular etiology of this disease, and preventative and disease-modifying therapies remain elusive. Recently, linkage studies have begun to identify single-gene mutations that are responsible for rare, heritable forms of PD, which offer an opportunity to gain insight into the molecular mechanisms of this disorder through the creation and analysis of appropriate animal models. One model system that is tractable for these studies is the fruit fly, Drosophila melanogaster. Analysis of several Drosophila models of PD has revealed some surprising insights into the pathogenesis of PD and begun to highlight potential treatment strategies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Drug Design; Humans; Nerve Tissue Proteins; Parkinson Disease; Ubiquitin-Protein Ligases

The concept of gliodegenerative diseases has not been widely established although there is accumulating evidence that glial cells may represent a primary target of degenerative disease processes. In the central nervous system (CNS), examples that provide a "proof of concept" include at least one alpha-synucleinopathy, multiple system atrophy (MSA), but this disease is conventionally discussed under the heading of "neurodegeneration". Additional evidence in support of primary glial affection has been reported in neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and transmissible spongiform encephalopathies. Based on biochemical, genetic and transcriptomic studies it is also becoming increasingly clear that the molecular changes measured in whole tissue extracts, e.g. obtained from Parkinson's disease brain, are not based on a purely neuronal contribution. This important evidence has been missed in cell culture or laser capture work focusing on the neuronal cell population. Studies of animal and in vitro models of disease pathogenesis additionally suggest glial accountability for some CNS degenerative processes. This review provides a critical analysis of the evidence available to date in support of the concept of gliodegeneration, which we propose to represent an essential although largely disregarded component of the spectrum of classical "neurodegeneration". Examples from the spectrum of alpha-synucleinopathies are presented.

Topics: alpha-Synuclein; Animals; Astrocytes; Cell Death; Cytokines; Disease Models, Animal; Gliosis; Humans; Myelin Sheath; Nerve Growth Factors; Neurodegenerative Diseases; Neuroglia

Expression of the Parkinson's disease-associated protein alpha-synuclein causes formation of aggregates and cytotoxicity in a great diversity of transgenic model organisms, in the case of Drosophila melanogaster affecting specific dopaminergic neuron clusters. The relative contribution of alpha-synuclein misfolding and phosphorylation for neurodegeneration was elucidated in these systems. In transgenic mice, typical neuropathologic inclusions formed concomitant with behavioral deficits, reminiscent of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Neuronal degeneration was cell-autonomous in the Lewy body disease models, whereas gliotic changes accompanied neurodegeneration caused by (oligodendro)glial cytoplasmic inclusions. These recent findings provided major insights into the molecular mechanisms of alpha-synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Neurodegenerative Diseases

The Ubiquitin Proteasome System is a multi-enzymatic pathway which degrades polyubiquinated soluble cytoplasmic proteins. This biochemical machinery is impaired both in sporadic and inherited forms of Parkinsonism. In the present paper we focus on the role of the pre-synaptic protein alpha-synuclein in altering the proteasom based on the results emerging from experimental models showing a mechanistic chain of events between altered alpha-synuclein, proteasome impairment and formation of neuronal inclusions and catecholamine cell death.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Amphetamines; Animals; Disease Models, Animal; Dopamine Agents; Humans; Parkinson Disease, Secondary; Proteasome Endopeptidase Complex; Ubiquitin

Intracellular fibrillar amyloid lesions comprised of tau proteins are pathological hallmarks in diverse neurodegenerative disorders. As models of these tauopathies, transgenic mice overexpressing tau with or without mutations discovered in familial tauopathies were generated. Findings in these tau transgenic mice support the notion that impairments of tau proteins are causally related to tauopathies, while studies on crossbred mice have indicated initiation and promotion of tau-positive neuropathologies by crosstalk among several pathogenic molecules. Enhancement of tau pathology by amyloid beta (Abeta) deposition provided some of the most compelling evidence for such a cross-talk, and molecular processes linking abnormalities of Abeta and tan have been suggested to involve activation of calcium-dependent protease, calpain, based on analyses of amyloid precursor protein transgenic mice crossbred with other genetically engineered mice with altered calpain activity. It also should be noted that mice transgenic for both tau and alpha-synuclein exhibit facilitated polymerization of these molecules into pathological filaments. Roles of fibrillar tau deposits in nervous system injuries can be mechanistically pursued by longitudinal monitoring of brain amyloidosis and neuroglial degeneration in the time course of antiamyloid intervention. The possibility of in vivo detection of tau-positive amyloid lesions has been demonstrated by intravenous administration of potential tracers into tau transgenic mice and subsequent brain imaging. Moreover, visualization of glial responses in living brains may allow sensitive detection of degenerative changes in the central nervous system.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Mice, Transgenic; tau Proteins; Tauopathies

Studies in yeast are providing critical insights into the mechanisms of neurodegeneration in Parkinson's disease (PD). A recent study shows that disruption of vesicular trafficking between the endoplasmic reticulum (ER) and the Golgi, caused by the overexpression and/or aggregation of alpha-synuclein, is linked to degeneration of dopamine neurons. Overexpression of proteins that are known to enhance ER-to-Golgi transport rescue defective trafficking in yeast, worm, fly, and cellular models of PD.

Topics: alpha-Synuclein; Animals; Biological Transport; Disease Models, Animal; Dopamine; Endoplasmic Reticulum; Golgi Apparatus; Humans; Models, Biological; Neurodegenerative Diseases; Neurons; Oxidative Stress; Parkinson Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by nigrostriatal dopaminergic degeneration and development of cytoplasmic inclusions known as Lewy bodies. To date, the mechanisms involved in PD pathogenesis are not clearly understood. Clues from genetic studies including identification of mutations in genes for alpha-synuclein, parkin, and ubiquitin carboxy hydrolase L1 associated with familial PD and the presence of proteinaceous cytoplasmic inclusions in spared dopaminergic nigral neurons in sporadic cases of PD have suggested an important role for ubiquitin-proteasome system (UPS) and aberrant protein degradation. In vivo and in vitro studies have linked parkin, alpha-synuclein, and oxidative stress to a compromised UPS and PD pathogenesis suggesting novel therapeutic targets.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Nerve Tissue Proteins; Parkinson Disease; Proteasome Endopeptidase Complex; Synucleins; Ubiquitin; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases

Parkinson's disease is predominantly a dopamine deficiency syndrome, which is produced in the brain by the loss of cells located in a small area in the ventral midbrain called the substantia nigra. Complete unilateral dopamine lesions, based on the administration of toxic substances (ie, 6-hydroxy-dopamine in rats and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in mice and primates) have been extremely useful in testing strategies of replacement. For example, the functional and biochemical impact of the transplanted ventral mesencephalic dopaminergic progenitors has been characterized to a large extent, using the complete lesion model in rats. Over the last decade, however, studies addressing the ability of neurotrophic factors to protect injured dopamine cells prompted researchers to make available partial and progressive lesion models to allow a window of opportunity to interfere the disease progression. Recent findings relating alpha-synuclein with Parkinson's disease pathology have opened new possibilities to develop alternative models based on the overexpression of this protein using recombinant adeno-associated viral vectors, which is valuable not only for helping to better understand its involvement in the disease process, but also to more closely resemble the neurodegeneration found in Parkinson's disease.

Topics: Adenoviridae; alpha-Synuclein; Animals; Disease Models, Animal; Disease Progression; Dopamine; Gene Expression; Gene Transfer Techniques; Genetic Vectors; Humans; Mice; Mice, Transgenic; Nerve Tissue Proteins; Parkinsonian Disorders; Rats; Recombination, Genetic; Substantia Nigra; Synucleins

Parkinson's disease is characterized by a progressive loss of dopaminergic neurons in the substantia nigra zona compacta, and in other sub-cortical nuclei associated with a widespread occurrence of Lewy bodies. The cause of cell death in Parkinson's disease is still poorly understood, but a defect in mitochondrial oxidative phosphorylation and enhanced oxidative and nitrative stresses have been proposed. We have studied control(wt) (C57B1/6), metallothionein transgenic (MTtrans), metallothionein double gene knock (MTdko), alpha-synuclein knock out (alpha-syn(ko)), alpha-synuclein-metallothionein triple knock out (alpha-syn-MTtko), weaver mutant (wv/wv) mice, and Ames dwarf mice to examine the role of peroxynitrite in the etiopathogenesis of Parkinson's disease and aging. Although MTdko mice were genetically susceptible to 1, methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine (MPTP) Parkinsonism, they did not exhibit any overt clinical symptoms of neurodegeneration and gross neuropathological changes as observed in wv/wv mice. Progressive neurodegenerative changes were associated with typical Parkinsonism in wv/wv mice. Neurodegenerative changes in wv/wv mice were observed primarily in the striatum, hippocampus and cerebellum. Various hallmarks of apoptosis including caspase-3, TNFalpha, NFkappaB, metallothioneins (MT-1, 2) and complex-1 nitration were increased; whereas glutathione, complex-1, ATP, and Ser(40)-phosphorylation of tyrosine hydroxylase, and striatal 18F-DOPA uptake were reduced in wv/wv mice as compared to other experimental genotypes. Striatal neurons of wv/wv mice exhibited age-dependent increase in dense cored intra-neuronal inclusions, cellular aggregation, proto-oncogenes (c-fos, c-jun, caspase-3, and GAPDH) induction, inter-nucleosomal DNA fragmentation, and neuro-apoptosis. MTtrans and alpha-Syn(ko) mice were genetically resistant to MPTP-Parkinsonism and Ames dwarf mice possessed significantly higher concentrations of striatal coenzyme Q10 and metallothioneins (MT 1, 2) and lived almost 2.5 times longer as compared to control(wt) mice. A potent peroxynitrite ion generator, 3-morpholinosydnonimine (SIN-1)-induced apoptosis was significantly attenuated in MTtrans fetal stem cells. These data are interpreted to suggest that peroxynitrite ions are involved in the etiopathogenesis of Parkinson's disease, and metallothionein-mediated coenzyme Q10 synthesis may provide neuroprotection.

Topics: alpha-Synuclein; Animals; Apoptosis; Brain; Coenzymes; Disease Models, Animal; Dopamine; Gene Expression Regulation; Humans; Metallothionein; Mice; Mice, Neurologic Mutants; Mice, Transgenic; MPTP Poisoning; Nerve Tissue Proteins; Parkinson Disease; Synucleins; Ubiquinone

Parkinson's disease (PD) is a debilitating neurodegenerative disease, with clinical features of tremor, muscular rigidity and akinesia, occurring as a result of midbrain dopamine loss. The search for treatments has relied heavily on animal models of the disorder. The use of monkey models of PD plays a distinct role in the development and assessment of novel treatments. The common marmoset (Callithrix jacchus) is a popular New World monkey used in the search for new treatments. These monkeys are easy to handle and survive well in captivity. This review examines the advantages of using marmoset monkeys in PD research and examines the different models available with reference to their use in pre-clinical assessment for novel therapeutic treatments. The most common models involve the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6-hydroxydopamine (6-OHDA). Recently, selective cerebral transgenic over-expression of alpha-synuclein has also been attempted in marmosets as a potential model for PD. Each model has its advantages. The MPTP-based model in marmosets resembles the disease with regards to the neuroanatomy of neurotransmitter loss; the unilateral application of 6-OHDA allows for the assessment of more complex sensorimotor deficits due to the presence of an intact 'control' side; the over-expression of alpha-synuclein in the midbrain results in the slow onset of behavioural symptoms allowing for a pre-symptomatic time window. The appropriateness of each of these marmoset models for the assessment of treatments depends on several factors including the experimental aim of the study and whether emphasis is placed on the analysis of behavioural deficits.

Topics: alpha-Synuclein; Animals; Callithrix; Disease Models, Animal; Humans; Oxidopamine; Parkinson Disease; Parkinsonian Disorders

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Patients with PD display a combination of motor symptoms including resting tremor, rigidity, bradykinesia, and postural instability that worsen over time. These motor symptoms are related to the progressive loss of dopamine neurons in the substantia nigra pars compacta. PD patients also suffer from nonmotor symptoms that may precede the cardinal motor symptoms and that are likely related to pathology in other brain regions. Traditional toxin models of PD have focused on the nigrostriatal pathway and the loss of dopamine neurons in this region, and these models have been important in our understanding of PD and in the development of symptomatic treatments for the disease. However, they are limited in that they do not reproduce the full pathology and progression seen in PD, thus creating a need for better models. The recent discovery of specific genes causing familial forms of PD has contributed to the development of novel genetic mouse models of PD. This review discusses the validity, benefits, and limitations of these new models.

Topics: alpha-Synuclein; Animals; Aphakia; Disease Models, Animal; DNA-Binding Proteins; Homeodomain Proteins; Humans; Intracellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Nuclear Receptor Subfamily 4, Group A, Member 2; Oncogene Proteins; Parkinson Disease; Protein Deglycase DJ-1; Transcription Factors; Ubiquitin-Protein Ligases

Alpha-synuclein (alpha-syn) is a small soluble protein expressed primarily at presynaptic terminals in the central nervous system. Interest in alpha-syn has increased dramatically after the discovery of a relationship between its dysfunction and several neurodegenerative diseases, including Parkinson's disease (PD). The physiological functions of alpha-syn remain to be fully defined, although recent data suggest a role in regulating membrane stability and neuronal plasticity. Various trigger factors, either environmental or genetic, can lead to a cascade of events involving misfolding or loss of normal function of alpha-syn. In dopaminergic neurons, this may promote a vicious cycle in which elevation in cytoplasmic dopamine, oxidative stress, alpha-syn dysfunction, and disruption of vesicle function lead to dopaminergic cell loss and PD. Alpha-syn dysfunction appears to be a common feature of all forms of PD. The mechanism by which alpha-syn induces neuronal cell toxicity may invoke multiple pathways, such as aggregation or interaction with other proteins and molecules, including synphilin-1, chaperone 14-3-3 protein, and dopamine itself. This complexity has hindered the development of models to study PD. The available animal models of PD, each present distinct advantages and limits. Findings to date suggest that alpha-syn-based models represent a paradigm, which is closest to the human pathology.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Disease Models, Animal; Humans; Molecular Sequence Data; Nerve Tissue Proteins; Parkinson Disease; Synucleins

The alpha-synuclein gene is implicated in Parkinson's disease, the symptoms of which occur after a marked loss of substantia nigra dopamine neurons. While the function of alpha-synuclein is not entirely elucidated, one function appears to be as a normal regulatory protein that can bind to and inhibit tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Soluble alpha-synuclein levels may be diminished in Parkinson's disease substantia nigra dopamine neurons both by reduced expression and by alpha-synuclein aggregation as Lewy bodies and Lewy neurites form. The loss of functional alpha-synuclein may then result in dysregulation of tyrosine hydroxylase, dopamine transport and dopamine storage, resulting in excess cytosolic dopamine. Because dopamine and its metabolites are reactive molecules capable of generating highly reactive quinones and reactive oxygen species, a failure to package dopamine into vesicles could cause irreversible damage to cellular macromolecules and contribute to resultant neurotoxicity. This review focuses on how a loss of normal alpha-synuclein function may contribute to the dopamine-related loss of substantia nigra neurons during Parkinson's disease pathogenesis.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Drosophila; Humans; Molecular Chaperones; Nerve Tissue Proteins; Neurons; Parkinson Disease; Synucleins; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a common neurodegenerative disorder. The etiology of PD is likely due to combinations of environmental and genetic factors. In addition to the loss of neurons, including dopaminergic neurons in the substantia nigra pars compacta, a further morphologic hallmark of PD is the presence of Lewy bodies and Lewy neurites. The formation of these proteinaceous inclusions involves interaction of several proteins, including alpha-synuclein, synphilin-1, parkin and UCH-L1. Animal models allow to get insight into the mechanisms of several symptoms of PD, allow investigating new therapeutic strategies and, in addition, provide an indispensable tool for basic research. In animals PD does not arise spontaneously, thus, characteristic and specific functional changes have to be mimicked by application of neurotoxic agents or by genetic manipulations. In this review we will focus on genes and gene loci involved in PD, the functions of proteins involved in the formation of cytoplasmatic inclusions, their interactions, and their possible role in PD. In addition, we will review the current animal models of PD.

Topics: alpha-Synuclein; Animals; Carrier Proteins; Cell Death; Disease Models, Animal; DNA-Binding Proteins; Humans; Leukocyte Common Antigens; Nerve Tissue Proteins; Neurotoxins; Parkinson Disease; Synucleins; Ubiquitin-Protein Ligases

Identified as the cause of some familial forms of Parkinson disease (PD) and as one of the major component of Lewy bodies, alpha-synuclein (alpha-syn) became the molecular hallmark of several neurodegenerative conditions now designated as synucleinopathies. Transgenic models have been generated to elucidate its physiological and pathologic roles. Although none of the lines created display dopaminergic neuronal death in the substantia nigra, the models recapitulate some features of synucleinopathies and are useful to study the potential pathogenic role of alpha-synuclein and its molecular partners. This review describes the different alpha-synuclein transgenic models, their clinical relevance to synucleinopathies, and their further utilization to understand the disease process.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Transgenic; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Lewy Bodies; Ligases; Mutation; Nerve Tissue Proteins; Neurons; Parkinson Disease; Protein Folding; Synucleins; Ubiquitin-Protein Ligases

Alpha-synuclein is a neuronal protein originally identified in Alzheimer's disease (AD) amyloid plaques in 1993 and named non-Abeta component precursor (NACP) [92]. Later, the discovery of two missense mutations (G88C and G209A), which resulted in Ala30Pro (A30P) and Ala53Thr (A53T) substitutions, of the alpha-synuclein gene in certain autosomal-dominant early onset familial Parkinson's disease (PD) has greatly promoted the understanding of the role of alpha-synuclein in the pathogenesis of neurodegenerative diseases, such as PD, dementia with Lewy bodies (DLB) and multiple system atrophy (MSA) [5,6,51,75]. At present, it is widely accepted that alpha-synuclein may play a central role in several neurodegenerative disorders because of the presence of insoluble alpha-synuclein as the major fibrillar component of inclusion bodies. From the cloning of the human alpha-synuclein cDNA in 1993 to the present, alpha-synuclein has been carefully documented in many aspects. In this article, we review the progress of studies on alpha-synuclein and its role in alpha-synuclein-related neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Cloning, Molecular; Disease Models, Animal; DNA, Complementary; Drosophila; Humans; Mice; Mice, Transgenic; Nerve Tissue Proteins; Neurodegenerative Diseases; Phosphoproteins; Synucleins

Following the identification of mutations in alpha-synuclein as the cause of some rare forms of familial Parkinson's disease (PD), genetic research has uncovered numerous gene loci of PD. Meanwhile, several neurodegenerative diseases have been shown to accumulate a-synuclein in neuronal and glial cells summarizing this group of diseases as synucleinopathies. All currently known gene defects causing PD alter the ubiquitin-proteasomal pathway of protein degradation. Identification of these disease mutations allows studying the functional consequences which lead to cellular dysfunction and cell death in cell culture and transgenic animal models, to identify therapeutic targets and to test potential protective strategies in these models.

Topics: Adjuvants, Immunologic; alpha-Synuclein; Animals; Antioxidants; Apoptosis; Disease Models, Animal; Genetics, Medical; Humans; Immunotherapy, Active; Iron; Microglia; Mitochondria; Nerve Tissue Proteins; Parkinson Disease; Substantia Nigra; Synucleins

Parkinson's disease (PD) is linked to mutations in the protein alpha-synuclein, which can exist in vitro in several aggregation states, including a natively unfolded monomer, a beta-sheet rich oligomer, or protofibril, and a stable amyloid fibril. This work reviews the current literature that is relevant to two linked questions: which of these species is pathogenic, and what is the mechanism of neurotoxicity? The amyloid fibril, fibrillar aggregates, Lewy bodies, and the alpha-synuclein monomer, which is normally expressed at high levels, are all unlikely to be pathogenic, for reasons discussed here. We therefore favor a toxic protofibril scenario, and propose that the pathogenic species is transiently populated during the process of fibrillization. Toxicity may arise from pore-like protofibrils that cause membrane permeabilization. An approach to testing this hypothesis is discussed.

Topics: alpha-Synuclein; Amino Acid Sequence; Amyloid; Animals; Brain; Disease Models, Animal; Humans; Mice; Molecular Sequence Data; Mutation; Nerve Tissue Proteins; Parkinson Disease; Synucleins

Parkinson's Disease (PD) is a common neurodegenerative disorder characterized by the progressive loss of dopamine neurons and the accumulation of Lewy bodies and neurites. Recent advances indicate that PD is due in some individuals to genetic mutations in alpha-synuclein, parkin, and ubiquitin C-terminal hydrolase L1 (UCHL1). All three PD-linked gene products are related directly or indirectly to the functioning of the cellular ubiquitin proteasomal system (UPS), suggesting that UPS dysfunction may be important in PD pathogenesis. Indeed, emerging evidence indicates that derangements of the UPS may be one of the underlying mechanisms of PD pathogenesis. The function of parkin as an ubiquitin protein ligase positions it as an important player in both familial and idiopathic PD. We recently demonstrated that parkin mediates a nondegradative form of ubiquitination on synphilin-1 that could contribute to synphilin-1's aggregation in PD. Our results implicate parkin involvement in the formation of Lewy bodies associated with sporadic PD. This review discusses the role of the UPS, as well as the modus operandi of the three PD candidate felons (alpha-synuclein, parkin, and UCHL1) along with their conspirators in bringing about dopaminergic cell death in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Ligases; Nerve Tissue Proteins; Parkinson Disease; Synucleins; Thiolester Hydrolases; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases

Accumulation and toxic conversion to protofibrils of alpha-synuclein has been associated with neurological disorders such as Parkinson's disease (PD), Lewy body disease, multiple system atrophy, neurodegeneration with brain iron accumulation type 1, and Alzheimer's disease. In recent years, modeling these disorders in transgenic (tg) mice and flies has helped improve understanding of the pathogenesis of these diseases and has established the basis for the development of new experimental treatments. Overexpression of alpha-synuclein in tg mice in a region- and cell-specific manner results in degeneration of selective circuitries accompanied by motor deficits and inclusion formation similar to what is found in PD and related disorders. Furthermore, studies in singly and doubly tg mice have shown that toxic conversion and accumulation can be accelerated by alpha-synuclein mutations associated with familial parkinsonism, by amyloid beta peptide 1-42 (Abeta 1-42), and by oxidative stress. In contrast, molecular chaperones such as Hsp70 and close homologues such as alpha-synuclein have been shown to suppress toxicity. Similar studies are underway to evaluate the effects of other modifying genes that might play a role in alpha-synuclein ubiquitination. Among them considerable interest has been placed on the role of molecules associated with familial parkinsonism (Parkin, UCHL-1). Furthermore, studying the targeted overexpression of alpha-synuclein and other modifier genes in the nigrostriatal and limbic system by using regulatable promoters, lentiviral vectors, and siRNA will help improve understanding of the molecular mechanisms involved in selective neuronal vulnerability, and it will aid the development of new treatments.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Humans; Nerve Tissue Proteins; Nervous System Diseases; Protein Processing, Post-Translational; Synucleins; Toxins, Biological

Defective handling of proteins is a central feature of major neurodegenerative diseases. The discovery that neuronal dysfunction or degeneration can be caused by mutations in single cellular proteins has given new opportunities to model the underlying disease processes by genetic modification of cells in vitro or by generation of transgenic animals carrying the disease-causing gene. Recent developments in recombinant viral-vector technology have opened up an interesting alternative possibility, based on direct gene transfer to selected subregions or subsets of neurons in the brain. Using the highly efficient adeno-associated virus or lentivirus vectors, recent reports have shown that overexpression of mutated human huntingtin or alpha-synuclein in neurons in the striatum or substantia nigra induces progressive neuropathology and neurodegeneration, similar to that seen in Huntington's and Parkinson's diseases. Targeted overexpression of disease-causing genes by recombinant viral vectors provides a new and highly flexible approach for in vivo modeling of neurodegenerative diseases, not only in mice and rats but also in primates.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Central Nervous System; Corpus Striatum; Dependovirus; Disease Models, Animal; Gene Transfer Techniques; Genetic Vectors; Huntingtin Protein; Huntington Disease; Lentivirus; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Neurons; Nuclear Proteins; Parkinson Disease; Substantia Nigra; Synucleins

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Lewy Body Disease; Macromolecular Substances; Nerve Tissue Proteins; Parkinson Disease; Protein Binding; Protein Structure, Tertiary; Synucleins

Alzheimer's disease (AD) is the most common cause of dementia that arises on a neuropathological background of amyloid plaques containing beta-amyloid (A beta) derived from amyloid precursor protein (APP) and tau-rich neurofibrillary tangles. To date, the cause and progression of both familial and sporadic AD have not been fully elucidated. The autosomal-dominant inherited forms of early-onset Alzheimer's disease are caused by mutations in the genes encoding APP, presenilin-1 (chromosome 14), and presenilin-2 (chromosome 1). APP is processed by several different proteases such as secretases and/or caspases to yield A beta and carboxyl-terminal fragments, which have been implicated in the pathogenesis of Alzheimer's disease. Alzheimer's disease and Parkinson's disease are associated with the cerebral accumulation of A beta and alpha-synuclein, respectively. Some patients have clinical and pathological features of both diseases, raising the possibility of overlapping pathogenic pathways. Recent studies have strongly suggested the possible pathogenic interactions between A beta, presenilins, and/or alpha-synuclein. Therefore, treatments that block the accumulation of A beta and alpha-synuclein might benefit a broad spectrum of neurodegenerative disorders. This review covers the trafficking and processing of APP, amyloid cascade hypothesis in AD pathogenesis, physiological and pathological roles of presenilins, molecular characteristics of alpha-synuclein, their interactions, and therapeutic strategies for AD.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Disease Models, Animal; Humans; Membrane Proteins; Mice; Mice, Transgenic; Nerve Tissue Proteins; Presenilin-1; Presenilin-2; Protein Transport; Synucleins

Neuronal death in Parkinson's disease (PD), one of the most common neurodegenerative disorders in the adult and aging population is probably caused by misfolding of synaptic proteins such as alpha-synuclein. Although, some treatments are currently available to control some of the symptoms of PD, none of these approaches directly addresses the mechanisms of disease. With the advent of new experimental animal models for this disorder, the potential for development and discovery of new treatment has been significantly bolstered. Among them, overexpression of alpha-synuclein results in motor deficits. dopaminergic loss and formation of inclusion bodies. Co-expression of mutant amyloid precursor protein, accelerates alpha-synuclein aggregation and enhances the neurodegenerative pathology in these mice, providing a unique model where to investigate the interactions between Abeta1-42 and alpha-synuclein and to develop treatments for combined Alzheimer's disease and PD. Development of anti-parkinsonian treatments based on these models includes: (i) anti-aggregation or pro-degradation compounds, (ii) neuroprotective compounds, and (iii) neurotrophic agents. Among them, we characterized beta-synuclein, the non-amyloidogenic homologue of alpha-synuclein, as an inhibitor of aggregation of alpha-synuclein. Our results raise the intriguing possibility that beta-synuclein might be a natural negative regulator of alpha-synuclein aggregation, and that a similar class of endogenous factors might regulate the aggregation state of other molecules involved in neurodegeneration. Such an anti-amyloidogenic property of beta-synuclein might also provide a novel strategy for the treatment of neurodegenerative disorders.

Topics: alpha-Synuclein; Amyloidosis; Animals; Animals, Genetically Modified; beta-Synuclein; Cell Aggregation; Disease Models, Animal; Humans; Nerve Tissue Proteins; Parkinson Disease, Secondary; Protein Binding; Protein Folding; Synucleins

Research into the pathogenesis of Parkinson's disease has been rapidly advanced by the development of animal models. Initial models were developed by using toxins that specifically targeted dopamine neurons, the most successful of which used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, a toxin that causes parkinsonism in man. More recently, the identification of alpha-synuclein mutations as a rare cause of Parkinson's disease has led to the development of alpha-synuclein transgenic mice and Drosophila. Here, I discuss the merits and limitations of these different animal models in our attempts to understand the physiology of Parkinson's disease and to develop new therapies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Humans; Nerve Tissue Proteins; Neurotoxins; Parkinsonian Disorders; Synucleins

Intracellular filamentous inclusions made of either the microtubule-associated protein tau or the protein alpha-synuclein define the majority of cases of neurodegenerative disease. Mutations in the tau gene in familial forms of frontotemporal dementia and in the alpha-synuclein gene in familial cases of Parkinson's disease have provided causal links between the dysfunction of these proteins and neurodegeneration. Over the past year, several novel tau gene mutations have been identified and more has been learned about possible mechanisms by which tau gene mutations lead to frontotemporal dementia. Experimental animal models have provided a link between tau filament formation and nerve cell degeneration. Along similar lines, animal models have been produced that result in the formation of alpha-synuclein filaments and the degeneration of dopaminergic nerve cells. Building on previous work, synthetic alpha-synuclein filaments have been shown to exhibit the characteristics of amyloid.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Inclusion Bodies; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins; tau Proteins

Topics: Adenine; alpha-Synuclein; Alzheimer Disease; Animals; Brain; Disease Models, Animal; Humans; Lewy Bodies; Mice; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Parkinson Disease; Point Mutation; Synucleins; Thymine

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Humans; Lewy Bodies; Lewy Body Disease; Multigene Family; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Sequence Homology, Amino Acid; Synucleins

Synucleinopathies such as Parkinson ́s disease (PD), Dementia with Lewy bodies (DLB) and Multiple System Atrophy (MSA) are characterized by deposition of misfolded and aggregated α-synuclein. Small aggregates (oligomers) of α-synuclein have been shown to be the most relevant neurotoxic species and are targeted by anle138b, an orally bioavailable small molecule compound which shows strong disease-modifying effects in animal models of synucleinopathies.. Anle138b was studied in a single-centre, double-blind, randomised, placebo-controlled single ascending dose (SAD) and multiple ascending dose (MAD) study in healthy subjects. Eligible participants were randomly assigned (1:1 for sentinel subjects and 1:5 for main group) to placebo or anle138b (dose range 50 mg to 300 mg per day), respectively. In addition, the effect of food on the pharmakokinetics of anle138b in healthy subjects was examined in doses of 150 mg per day. Participants were randomized to treatment sequence (fed→fasted) or (fasted→fed). Treatment was administered orally in hard gelatine capsules containing either 10 mg or 30 mg of anle138b or excipient only. The primary endpoints were safety and tolerability, the secondary endpoint was pharmakokinetics. Data from all randomized individuals were evaluated.. gov-identifier: NCT04208152. EudraCT-number: 2019-004218-33.. Between December 17. The favourable safety and PK profile of anle138b in doses resulting in exposures above the fully effective plasma level in a mouse Parkinson model warrant further clinical trials in patients with synucleinopathies.. This study was funded by MODAG GmbH and by the Michael J. Fox foundation for Parkinson's Research.

Topics: alpha-Synuclein; Animals; Benzodioxoles; Disease Models, Animal; Double-Blind Method; Humans; Mice; Parkinson Disease; Pyrazoles; Synucleinopathies

The Total Glucosides of White Paeony Capsule (TGPC), one of the traditional Chinese patent medicines, has been used for the treatment of autoimmune diseases such as rheumatoid arthritis (RA) in clinical practice. Besides, the components of TGPC are extracted from Radix Paeoniae Alba (RPA) and have displayed neuroprotective properties.. The present study was designed to evaluate the anti-PD-like effects of TGPC on a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced mice model and explore its potential molecular mechanisms.. Behavioral tests, hematoxylin and eosin (HE) staining, Nissl staining, immunohistochemistry (IHC), western blotting (WB) and Enzyme-Linked Immunosorbent Assay (ELISA) were performed in this study.. It was observed that TGPC treatment (150, 300 mg/kg) significantly reversed MPTPinduced PD-like behaviors, such as reduced locomotive activity in the open field test, prolonged time to turn downward on the ball (T-turn) and to climb down the whole pole (T-descend) in the pole test, decreased movement scores in the traction test and extended the latency to fall in the hanging wire test. In addition, TGPC improved neurodegeneration, inhibited the excessive activation of microglia and suppressed the overproduction of proinflammatory cytokines induced by MPTP, partially by restoring leucine-rich repeat kinase 2 (LRRK2) activity and inhibiting alpha-synuclein (α-syn) mediated neuroinflammation signaling.. Taken together, TGPC exhibited neuroprotective effects on MPTP-induced mice model of PD, which was associated with the prevention of neuroinflammation and neurodegeneration modulated by LRRK2/α-syn pathway.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Glucosides; Mice; Mice, Inbred C57BL; Neuroinflammatory Diseases; Neuroprotective Agents; Paeonia; Parkinson Disease

Multiple system atrophy is a progressive neurodegenerative disease with prominent autonomic and motor features. During early stages, different subtypes of the disease are distinguished by their predominant parkinsonian or cerebellar symptoms, reflecting its heterogeneous nature. The pathognomonic feature of multiple system atrophy is the presence of α-synuclein (αSyn) protein deposits in oligodendroglial cells. αSyn can assemble in specific cellular or disease environments and form αSyn strains with unique structural features, but the ability of αSyn strains to propagate in oligodendrocytes remains elusive. Recently, it was shown that αSyn strains with related conformations exist in the brains of patients. Here, we investigated whether different αSyn strains can influence multiple system atrophy progression in a strain-dependent manner. To this aim, we injected two recombinant αSyn strains (fibrils and ribbons) in multiple system atrophy transgenic mice and found that they determined disease severity in multiple system atrophy via host-restricted and cell-specific pathology in vivo. αSyn strains significantly impact disease progression in a strain-dependent way via oligodendroglial, neurotoxic and immune-related mechanisms. Neurodegeneration and brain atrophy were accompanied by unique microglial and astroglial responses and the recruitment of central and peripheral immune cells. The differential activation of microglial cells correlated with the structural features of αSyn strains both in vitro and in vivo. Spectral analysis showed that ribbons propagated oligodendroglial inclusions that were structurally distinct from those of fibrils, with resemblance to oligodendroglial inclusions, in the brains of patients with multiple system atrophy. This study, therefore, shows that the multiple system atrophy phenotype is governed by both the nature of the αSyn strain and the host environment and that by injecting αSyn strains into an animal model of the disease, a more comprehensive phenotype can be established.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Mice, Transgenic; Multiple System Atrophy; Patient Acuity

Parkinson disease (PD) is considered as one of the most worldwide neurodegenerative disorders. The major reasons associated to neurodegeneration process of PD pathogenesis are oxidative stress. Many studies reported that natural antioxidant molecules, especially, curcumin can suppress inflammatory pathways and preserve dopaminergic neurons damage in PD. Further, the poor pharmacokinetics, instability of chemical structure because of fast hydrolytic degradation at physiologic condition and especially, the presence of the blood brain barrier (BBB) has regarded as a considerable restriction factor for transfer of neurotherapeutic molecules to the brain tissue. The present research aims to the fabrication of nanoformulated curcumin loaded human endometrial stem cells derived exosomes (hEnSCs EXOs-Cur) to study on enhancing curcumin penetration to the brain across BBB and to improve anti- Parkinsonism effects of curcumin against neural death and alpha-synuclein aggregation. hEnSCs EXOs-Cur characterization results demonstrated the accurate size and morphology of formulated curcumin loaded exosomes with a proper stability and sustained release profile. In vivo studies including behavioral, Immunohistochemical and molecular evaluations displayed that novel formulation of hEnSCs EXO-Cur is able to cross BBB, enhance motor uncoordinated movements, suppress the aggregation of αS protein and rescue neuronal cell death through elevation of BCL2 expression level as an anti-apoptotic protein and the expression level reduction of BAX and Caspase 3 as apoptotic markers.

Topics: alpha-Synuclein; Animals; Curcumin; Disease Models, Animal; Exosomes; Humans; Mice; Parkinson Disease

2-(Quinoline-8-carboxamido)benzoic acid (2-QBA;

Topics: 1-Methyl-4-phenylpyridinium; Alkaloids; alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Fungi; Neuroprotective Agents; Parkinson Disease; Quinolines

The p.Thr61Ile (p.T61I) mutation in coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) was deemed a causative factor in Parkinson's disease (PD). However, the pathomechanism of the CHCHD2 p.T61I mutation in PD remains unclear. Few existing mouse models of CHCHD2-related PD completely reproduce the features of PD, and no transgenic or knock-in (KI) mouse models of CHCHD2 mutations have been reported. In the present study, we generated a novel CHCHD2 p.T61I KI mouse model, which exhibited accelerated mortality, progressive motor deficits, and dopaminergic (DA) neurons loss with age, accompanied by the accumulation and aggregation of α-synuclein and p-α-synuclein in the brains of the mutant mice. The mitochondria of mouse brains and induced pluripotent stem cells (iPSCs)-derived DA neurons carrying the CHCHD2 p.T61I mutation exhibited aberrant morphology and impaired function. Mechanistically, proteomic and RNA sequencing analysis revealed that p.T61I mutation induced mitochondrial dysfunction in aged mice likely through repressed insulin-degrading enzyme (IDE) expression, resulting in the degeneration of the nervous system. Overall, this CHCHD2 p.T61I KI mouse model recapitulated the crucial clinical and neuropathological aspects of patients with PD and provided a novel tool for understanding the pathogenic mechanism and therapeutic interventions of CHCHD2-related PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; DNA-Binding Proteins; Mice; Parkinson Disease; Proteomics; Transcription Factors

Accumulation and propagation of pathological α-synuclein (α-Syn) are the major contributing factors to the pathogenesis of Parkinson's disease (PD). Therapy to halt the spreading of α-Syn pathology needs to be established.. After phage display and affinity maturation, human-derived anti-α-Syn autoantibodies were selected and applied to biochemical, cellular and animal models of PD.. The novel naturally occurring anti-α-Syn autoantibodies (α-Syn-nAbs), P21 and P22, selectively bind α-Syn preformed fibrils (PFFs), recognise Lewy bodies (LBs) and Lewy neurites (LNs) in human PD brains, block α-Syn fibrillization and inhibit the seeding of α-Syn PFFs. Moreover, systematic administration of P21 and P22 attenuates α-Syn pathology, degeneration of the nigrostriatal pathway and motor deficits in mice injected with α-Syn PFFs.. P21 and P22 attenuate α-synuclein pathology and are promising candidates for PD treatment.

Topics: alpha-Synuclein; Animals; Autoantibodies; Brain; Disease Models, Animal; Humans; Mice; Parkinson Disease; Synucleinopathies

Parkinson's disease (PD) is the second most common neurodegenerative disorder and is caused by the loss of dopaminergic neurons in the substantia nigra (SN). However, the reason for the death of dopaminergic neurons remains unclear. An increase in α-synuclein (α-syn) expression is an important factor in the pathogenesis of PD. In the current study, we investigated the association between serine/arginine-rich protein-specific kinase 3 (Srpk3) and PD in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model and in SH-SY5Y cells treated with 1-methyl-4-phenylpyridinium (MPP+). Srpk3 expression was significantly downregulated, while tyrosine hydroxylase (TH) expression decreased and α-syn expression increased after 4 weeks of MPTP treatment. Dopaminergic cell reduction and α-syn expression increase were demonstrated by Srpk3 expression inhibition by siRNA in SH-SY5Y cells. Moreover, a decrease in Srpk3 expression upon siRNA treatment promoted dopaminergic cell reduction and α-syn expression increase in SH-SY5Y cells treated with MPP+ . These results suggested that Srpk3 expression decrease due to Srpk3 siRNA caused both TH level decrease and α-syn expression increase. This raises new possibilities for studying how Srpk3 controls dopaminergic cells and α-syn expression, which may be related to PD pathogenesis. Our results provide an avenue for understanding the role of Srpk3 in dopaminergic cell loss and α-syn upregulation in SN. Furthermore, this study supports a therapeutic possibility for PD in that the maintenance of Srpk3 expression inhibits dopaminergic cell reduction.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Inbred C57BL; Neuroblastoma; Parkinson Disease; Protein Serine-Threonine Kinases; RNA, Small Interfering; Substantia Nigra

Parkinson's disease (PD) is a neurodegenerative disorder characterized by both motor and non-motor features. The current treatment regimen for PD are dopamine enhancers which have been reported to worsen the disease prognosis after long term treatment, thus, the need for better treatment options. This study sought to investigate the protective action of Double Stem Cell® (DSC), a blend of stem cells extracts from Swiss apples (Malus Domestica) and Burgundy grapes (Vitis vinifera) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism in mice and genetic model of PD in Drosophila melanogaster. Male albino mice were pretreated with MPTP (4 × 20 mg/kg, i.p., two hourly in 8 h), twelve hours before administration of DSC (8, 40, or 200 mg/kg, p.o.). Thereafter, behavioural, biochemical and immunohistochemical assays were carried out. The impact of vehicle or DSC supplementation on α-synuclein aggregation was evaluated in Drosophila melanogaster using the UAS-Gal4 system, female DDC-Gal4 flies were crossed with male UAS-α-synuclein, the progenies were examined for fecundity, locomotion, memory, and lifespan. MPTP-induced motor deficits in open field test (OFT), working memory impairment (Y-maze test (YMT)) and muscle incoordination (rotarod test) were ameliorated by DSC (8, 40 or 200 mg/kg) through dose-dependent and significant improvements in motor, cognitive and motor coordination. Moreso, MPTP exposure caused significant increase in lipid peroxidation and decrease in antioxidant enzymes activities (glutathione, catalase and superoxide dismutase) in the midbrain which were attenuated by DSC. MPTP-induced expression of microglia (iba-1), astrocytes (glia fibrillary acidic protein; GFAP) as well as degeneration of dopamine neurons (tyrosine hydroxylase positive neurons) in the substantia nigra (SN) were reversed by DSC. Supplementation of flies feed with graded concentration of DSC (0.8, 4 or 20 mg/ml) did not affect fecundity but improved climbing activity and lifespan. Findings from this study showed that Double Stem Cell improved motor and cognitive functions in both mice and Drosophila through attenuation of neurotoxin-induced oxidative stress and neuroinflammation.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antioxidants; Disease Models, Animal; Dopaminergic Neurons; Drosophila melanogaster; Mice; Mice, Inbred C57BL; Models, Genetic; Neuroinflammatory Diseases; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Plant Extracts; Substantia Nigra

Parkinson's disease remains orphan of valuable therapies capable to interfere with the disease pathogenesis despite the large number of symptomatic approaches adopted in clinical practice to manage this disease. Treatments simultaneously affecting α-synuclein (α-syn) oligomerization and neuroinflammation may counteract Parkinson's disease and related disorders. Recent data demonstrate that Doxycycline, a tetracycline antibiotic, can inhibit α-syn aggregation as well as neuroinflammation. We herein investigate, for the first time, the potential therapeutic properties of Doxy in a human α-syn A53T transgenic Parkinson's disease mouse model evaluating behavioural, biochemical and histopathological parameters.. Human α-syn A53T transgenic mice were treated with Doxycycline (10 mg/kg daily ip) for 30 days. The effect of treatment on motor, cognitive and daily live activity performances were examined. Neuropathological and neurophysiological parameters were assessed through immunocytochemical, electrophysiological and biochemical analysis of cerebral tissue.. Doxy treatment abolished cognitive and daily life activity deficiencies in A53T mice. The effect on cognitive functions was associated with neuroprotection, inhibition of α-syn oligomerization and gliosis both in the cortex and hippocampus. Doxy treatment restored hippocampal long-term potentiation in association with the inhibition of pro-inflammatory cytokines expression. Moreover, Doxy ameliorated motor impairment and reduced striatal glial activation in A53T mice.. Our findings promote Doxy as a valuable multi-target therapeutic approach counteracting both symptoms and neuropathology in the complex scenario of α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Doxycycline; Drug Repositioning; Humans; Mice; Mice, Transgenic; Neuroinflammatory Diseases; Parkinson Disease; Synucleinopathies

The lack of evidence indicating the accumulation of phosphorylated α-synuclein (P-α-syn), a neuropathological hallmark of Parkinson disease (PD), limits the application of 6-OHDA animal models. In cynomolgus monkeys received unilateral 6-hydroxydopamine (6-OHDA) injection, we identified nigrostriatal dysfunction related behavioral defects, such as the increase of PD score, decrease of locomotor activities, and exhibition of typical rotations. We found the dopaminergic neurons were significantly reduced and had fragmented morphology in substantia nigra (SN). Furthermore, insoluble P-α-syn aggregates were observed. The P-α-syn aggregates were extracellular distributed and had typical morphology of inclusion. Immunofluorescence staining showed that the P-α-syn colocalized with ubiquitin (Ub) and p62. We also found there were more actived astrocytes and microglial in SN and striatum, reflecting neuroinflammations increase in nigrostriatal pathway. At last, to determine the long-term consequence of dopamine (DA) neuron loss induced by 6-OHDA injection, the changes of cerebrospinal fluid (CSF) neurotransmitters over time as well as the brain microstructure alternations were examined. The dopamine-related metabolites were decreased after 6-OHDA injection reflecting dopaminergic neuron loss. The levels of γ-aminobutyric acid (GABA) and acetylcholine (Ach) showed an increasing trend but not significant. By diffusion tensor Magnetic Resonance Imaging (MRI) image scans, the fractional anisotropy (FA) value in the ipsilateral SN and caudate was found to reduce, which indicated neural fiber injury. Therefore, these results suggested that α-syn pathology might participate in process of 6-OHDA injuring DA neurons, and may expand the application of 6-OHDA monkeys on investigations into the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Macaca fascicularis; Nerve Degeneration; Oxidopamine; Parkinson Disease; Substantia Nigra

Accumulation of alpha-synuclein (α-syn) is central to the pathogenesis of Parkinson's disease (PD). Previous studies suggest that α-syn pathology may originate from the olfactory bulb (OB) or gut in response to an unknown pathogen and later progress to the different brain regions. Aging is viewed as the utmost threat to PD development. Therefore, studies depicting the role of age in α-syn accumulation and its progression in PD are important. In the present study, we gave intranasal rotenone microemulsion for 6 weeks in 12-month-old female BALB/c mice and found olfactory dysfunction after 4 and 6 weeks of rotenone administration. Interestingly, motor impairment was observed only after 6 weeks. The animals were sacrificed after 6 weeks to perform western blotting and immunohistochemical studies to detect α-syn pathology, neuroinflammation and neurodegeneration. We found α-syn accumulation in OB, striatum, substantia nigra (SN) and cortex. Importantly, we found significant glial cell activation and neurodegeneration in all the analysed regions which were absent in our previous published studies with 3 months old mice even after they were exposed to rotenone for 9 weeks indicating age is a crucial factor for α-syn induced neuroinflammation and neurodegeneration. We also observed increased iron accumulation in SN of rotenone-exposed aged mice. Moreover, inflammaging was observed in OB and striatum of 12-month-old BALB/c mice as compared to 3-month-old BALB/c mice. In conclusion, there is a difference in sensitivity between adult and aged mice in the development and progression of α-syn pathology and subsequent neurodegeneration, for which inflammaging might be the crucial probable mechanism.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Mice; Neuroinflammatory Diseases; Parkinson Disease; Rotenone

Aggregated α-synuclein, a major constituent of Lewy bodies plays a crucial role in the pathogenesis of α-synucleinopathies (SPs) such as Parkinson's disease (PD). PD is affected by the innate and adaptive arms of the immune system, and recently both active and passive immunotherapies targeted against α-synuclein are being trialed as potential novel treatment strategies. Specifically, dendritic cell-based vaccines have shown to be an effective treatment for SPs in animal models. Here, we report on the development of adoptive cellular therapy (ACT) for SP and demonstrate that adoptive transfer of pre-activated T-cells generated from immunized mice can improve survival and behavior, reduce brain microstructural impairment via magnetic resonance imaging (MRI), and decrease α-synuclein pathology burden in a peripherally induced preclinical SP model (M83) when administered prior to disease onset. This study provides preclinical evidence for ACT as a potential immunotherapy for LBD, PD and other related SPs, and future work will provide necessary understanding of the mechanisms of its action.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Transgenic; Parkinson Disease; Synucleinopathies; Vaccines

Parkinson's disease (PD) is characterized by multiple symptoms including olfactory dysfunction, whose underlying mechanisms remain unclear. Here, we explored pathologic changes in the olfactory pathway of transgenic (Tg) mice of both sexes expressing the human A30P mutant α-synuclein (α-syn; α-syn-Tg mice) at 6-7 and 12-14 months of age, representing early and late-stages of motor progression, respectively. α-Syn-Tg mice at late stages exhibited olfactory behavioral deficits, which correlated with severe α-syn pathology in projection neurons (PNs) of the olfactory pathway. In parallel, olfactory bulb (OB) neurogenesis in α-syn-Tg mice was reduced in the OB granule cells at six to seven months and OB periglomerular cells at 12-14 months, respectively, both of which could contribute to olfactory dysfunction. Proteomic analyses showed a disruption in endocytic and exocytic pathways in the OB during the early stages which appeared exacerbated at the synaptic terminals when the mice developed olfactory deficits at 12-14 months. Our data suggest that (1) the α-syn-Tg mice recapitulate the olfactory functional deficits seen in PD; (2) olfactory structures exhibit spatiotemporal disparities for vulnerability to α-syn pathology; (3) α-syn pathology is restricted to projection neurons in the olfactory pathway; (4) neurogenesis in adult α-syn-Tg mice is reduced in the OB; and (5) synaptic endocytosis and exocytosis defects in the OB may further explain olfactory deficits.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Transgenic; Neurogenesis; Olfaction Disorders; Parkinson Disease; Proteomics; Smell

Alzheimer's disease (AD) and Parkinson's disease (PD) are age-dependent neurodegenerative disorders. There is a profound neuronal loss in the basal forebrain cholinergic system in AD and severe dopaminergic deficiency within the nigrostriatal pathway in PD. Swedish APP (APP

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Disease Models, Animal; Dopaminergic Neurons; Mice; Parkinson Disease; Syndecan-3

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. The standard treatments for PD focus on symptom relief rather than attempting to address the underlying degenerative processes completely. This study aimed to evaluate the potential therapeutic effects of policosanol derived from insect wax (PIW) by investigating improvements in disease symptoms represented in Caenorhabditis elegans models of PD. For our assessments, we used the following three models: NL5901, which is a transgenic model for α-synuclein aggregation; wild-type N2 induced with 6-hydroxydopamine (6-OHDA); and 6-OHDA-induced BZ555 as a model for loss of dopaminergic neurons (DNs). Specifically, we examined the effects of PIW treatment on α-synuclein aggregation, the loss of DNs, lipid abundance, and the lifespan of treated organisms. Further, we examined treatment-related changes in the levels of reactive oxygen species (ROS), malondialdehyde (MDA), adenosine triphosphate (ATP), glutathione S-transferase (GST), and superoxide dismutase (SOD), as well as the mRNA production profiles of relevant genes. A 10 µg/mL dose of PIW reduced the aggregation of α-synuclein in NL5901 and suppressed the loss of DNs in 6-OHDA-induced BZ555. Overall, PIW treatment decreased ROS and MDA levels, restored lipid abundance, and prolonged the lifespans of worms in all the three models, which may be associated with changes in the expression profiles of genes related to cell survival and oxidative stress response pathways. Our findings show that PIW alleviated the symptoms of PD in these models, possibly by regulating the stress responses initiated by injuries such as α-synuclein aggregation or 6-OHDA treatment.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Fatty Alcohols; Neurodegenerative Diseases; Oxidopamine; Parkinson Disease; Reactive Oxygen Species

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease of the central nervous system, with an estimated 5,000,000 cases worldwide. PD pathology is characterized by the accumulation of misfolded α-synuclein, which is thought to play a critical role in the pathogenesis of the disease. Animal models of PD suggest that activation of Abelson tyrosine kinase (c-Abl) plays an essential role in the initiation and progression of α-synuclein pathology and initiates processes leading to degeneration of dopaminergic and nondopaminergic neurons. Given the potential role of c-Abl in PD, a c-Abl inhibitor library was developed to identify orally bioavailable c-Abl inhibitors capable of crossing the blood-brain barrier based on predefined characteristics, leading to the discovery of IkT-148009. IkT-148009, a brain-penetrant c-Abl inhibitor with a favorable toxicology profile, was analyzed for therapeutic potential in animal models of slowly progressive, α-synuclein-dependent PD. In mouse models of both inherited and sporadic PD, IkT-148009 suppressed c-Abl activation to baseline and substantially protected dopaminergic neurons from degeneration when administered therapeutically by once daily oral gavage beginning 4 weeks after disease initiation. Recovery of motor function in PD mice occurred within 8 weeks of initiating treatment concomitantly with a reduction in α-synuclein pathology in the mouse brain. These findings suggest that IkT-148009 may have potential as a disease-modifying therapy in PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopaminergic Neurons; Mice; Neurodegenerative Diseases; Parkinson Disease; Proto-Oncogene Proteins c-abl; Synucleinopathies

Parkinson's disease (PD) is characterized pathologically by abnormal aggregation of alpha-synuclein (α-Syn) in the brain and clinically by fine movement deficits at the early stage, but the roles of α-Syn and associated neural circuits and neuromodulator bases in the development of fine movement deficits in PD are poorly understood, in part due to the lack of appropriate behavioral testing paradigms and PD models without motor confounding effects. Here, we coupled two unique behavioral paradigms with two PD models to reveal the following: (i) Focally injecting α-Syn fibrils into the dorsolateral striatum (DLS) and the transgenic expression of A53T-α-Syn in the dopaminergic neurons in the substantia nigra (SN, PITX3-IRES2-tTA/tetO-A53T mice) selectively impaired forelimb fine movements induced by the single-pellet reaching task. (ii) Injecting α-Syn fibers into the SN suppressed the coordination of cranial and forelimb fine movements induced by the sunflower seed opening test. (iii) Treatments with the adenosine A

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Mice; Parkinson Disease; Receptor, Adenosine A2A; Substantia Nigra

Aggregation of misfolded α-synuclein (α-syn) protein in the periphery and central nervous system (CNS) gives rise to a group of disorders, which are labeled collectively as synucleinopathies. These clinically distinct disorders are known as pure autonomic failure, Parkinson's disease (PD), Parkinson's disease dementia (PDD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). In the case of PD, it has been demonstrated that toxic aggregates of α-syn protein not only cause apoptosis of dopamine neurons but its accumulation in the neocortex and limbic area principally contributes to dementia. In our multifunctional drug discovery research for PD, we converted one of our catechol-containing lead dopamine agonist molecules

Topics: alpha-Synuclein; Animals; Dementia; Disease Models, Animal; Humans; Lewy Body Disease; Mice; Parkinson Disease; Prodrugs

α-Synuclein is a major component of Lewy bodies (LB) and Lewy neurites (LN) appearing in the postmortem brain of Parkinson's disease (PD) and other α-synucleinopathies. While most studies of α-synucleinopathies have focused on neuronal and synaptic alterations as well as dysfunctions of the astrocytic homeostatic roles, whether the bidirectional astrocyte-neuronal communication is affected in these diseases remains unknown. We have investigated whether the astrocyte Ca

Topics: alpha-Synuclein; Animals; Astrocytes; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Parkinson Disease; Synucleinopathies

Increasing evidence suggests that patients with Parkinson's disease (PD) present with peripheral autonomic dysfunction (AutD) that even precedes motor deficits, through which α-synuclein can spread to the central nervous system. However, the pathological mechanisms underlying AutD in prodromal PD remain unclear. Here, we investigated the role of α-synuclein and its interplay with the activation of Schwann cells (SCs) of the vagus nerve in AutD.. Rats were subjected to injection with adeno-associated viruses containing the human mutated A53T gene (AAV-A53T) or an empty vector into the left cervical vagus nerve and evaluated for gastrointestinal symptoms, locomotor functions, intestinal blood flow, and nerve electrophysiology. Further, we examined the impact of α-synucleinopathy on vagus nerves, SCs, and central nervous system neurons using electron microscopy, immunofluorescence, immunohistochemistry, and western blot. Finally, the role of Toll-like receptor 2 (TLR2) in regulating the neuroinflammation in the vagus nerve via MyD88 and NF-κB pathway was determined using genetic knockdown.. We found that rats injected with AAV-A53T in the vagus nerve exhibited prominent signs of AutD, preceding the onset of motor deficits and central dopaminergic abnormalities by at least 3 months, which could serve as a model for prodromal PD. In addition, reduced intestinal blood flow and decreased nerve conduction velocity were identified in AAV-A53T-injected rats, accompanied by disrupted myelin sheaths and swollen SCs in the vagus nerve. Furthermore, our data demonstrated that p-α-synuclein was deposited in SCs but not in axons, activating the TLR2/MyD88/NF-κB signaling pathway and leading to neuroinflammatory responses. In contrast, silencing the TLR2 gene not only reduced inflammatory cytokine expression but also ameliorated vagal demyelination and secondary axonal loss, consequently improving autonomic function in rats.. These observations suggest that overexpression of α-synuclein in the vagus nerve can induce symptoms of AutD in prodromal PD, and provide support for a deeper understanding of the pathological mechanisms underlying AutD and the emergence of effective therapeutic strategies for PD.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Animals; Disease Models, Animal; Humans; Myeloid Differentiation Factor 88; NF-kappa B; Parkinson Disease; Prodromal Symptoms; Rats; Schwann Cells; Toll-Like Receptor 2; Vagus Nerve

Parkinson's disease (PD) is a debilitating neurodegenerative multisystem disorder leading to motor and non-motor symptoms in millions of individuals. Despite intense research, there is still no cure, and early disease biomarkers are lacking. Animal models of PD have been inspired by basic elements of its pathogenesis, such as dopamine dysfunction, alpha-synuclein accumulation, neuroinflammation and disruption of protein degradation, and these have been crucial for a deeper understanding of the mechanisms of pathology, the identification of biomarkers, and evaluation of novel therapies. Imaging biomarkers are non-invasive tools to assess disease progression and response to therapies; their discovery and validation have been an active field of translational research. Here, we highlight different considerations of animal models of PD that can be applied to future research, in terms of their suitability to answer different research questions. We provide the reader with important considerations of the best choice of model to use based on the disease features of each model, including issues related to different species. In addition, positron emission tomography studies conducted in PD animal models in the last 5 years are presented. With a variety of different species, interventions and genetic information, the choice of the most appropriate model to answer research questions can be daunting, especially since no single model recapitulates all aspects of this complex disorder. Appropriate animal models in conjunction with in vivo molecular imaging tools, if selected properly, can be a powerful combination for the assessment of novel therapies and developing tools for early diagnosis.

Topics: alpha-Synuclein; Animals; Biomarkers; Disease Models, Animal; Disease Progression; Parkinson Disease; Positron-Emission Tomography

The mechanisms of cognitive impairments in Parkinson's disease (PD) remain unknown. Accumulating evidence revealed that brain neuroinflammatory response mediated by microglial cells contributes to cognitive deficits in neuropathological conditions and macrophage antigen complex-1 (Mac1) is a key factor in controlling microglial activation.. To explore whether Mac1-mediated microglial activation participates in cognitive dysfunction in PD using paraquat and maneb-generated mouse PD model.. Cognitive performance was measured in wild type and Mac1. Genetic deletion of Mac1 significantly ameliorated learning and memory impairments, neuronal damage, synaptic loss and α-synuclein phosphorylation (Ser129) caused by paraquat and maneb in mice. Subsequently, blocking Mac1 activation was found to mitigate paraquat and maneb-elicited microglial NLRP3 inflammasome activation in both in vivo and in vitro. Interestingly, stimulating activation of NOX by phorbol myristate acetate abolished the inhibitory effects of Mac1 blocking peptide RGD on paraquat and maneb-provoked NLRP3 inflammasome activation, indicating a key role of NOX in Mac1-mediated NLRP3 inflammasome activation. Furthermore, NOX1 and NOX2, two members of NOX family, and downstream PAK1 and MAPK pathways were recognized to be essential for NOX to regulate NLRP3 inflammasome activation. Finally, a NLRP3 inflammasome inhibitor glybenclamide abrogated microglial M1 activation, neurodegeneration and phosphorylation (Ser129) of α-synuclein elicited by paraquat and maneb, which were accompanied by improved cognitive capacity in mice.. Mac1 was involved in cognitive dysfunction in a mouse PD model through NOX-NLRP3 inflammasome axis-dependent microglial activation, providing a novel mechanistic basis of cognitive decline in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Inflammasomes; Integrins; Macrophage-1 Antigen; Macrophages; Maneb; Memory Disorders; Mice; Microglia; NADPH Oxidases; NLR Family, Pyrin Domain-Containing 3 Protein; Paraquat; Parkinson Disease

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder. Increasing evidence suggests the role of the gut-microbiota-brain axis in the pathogenesis of PD. Mesenchymal stem-cell-derived microvesicles (MSC-MVs) have emerged as a therapeutic potential for neurological disorders over the last years.. The objective of this study was to investigate whether MSC-MVs could improve PD-like neurotoxicity in mice after administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine).. MPTP-induced reductions in the dopamine transporter and tyrosine hydroxylase expressions in the striatum and substantia nigra (SNr) were attenuated after a subsequent single administration of MSC-MVs. Increases in the phosphorylated α-synuclein (p-α-Syn)/α-Syn ratio in the striatum, SNr, and colon after MPTP injection were also attenuated after MSC-MVs injection. Furthermore, MSC-MVs restored MPTP-induced abnormalities of the gut microbiota composition. Interestingly, positive correlations between the genus Dubosiella and the p-α-Syn/α-Syn ratio were observed in the brain and colon, suggesting their roles in the gut-microbiota-brain communication. Moreover, MSC-MVs attenuated MPTP-induced reduction of the metabolite, 3,6-dihydroxy-2-[3-methoxy-4-(sulfooxy)phenyl]-7-(sulfinooxy)-3,4-dihydro-2H-1-benzopyran-5-olate, in the blood. Interestingly, a negative correlation between this compound and the p-α-Syn/α-Syn ratio was observed in the brain and colon.. These data suggest that MSC-MVs could ameliorate MPTP-induced neurotoxicity in the brain and colon via the gut-microbiota-brain axis. Therefore, MSC-MVs would have a new therapeutic potential for neurological disorders such as PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Gastrointestinal Microbiome; Mice; Mice, Inbred C57BL; MPTP Poisoning; Parkinson Disease; Substantia Nigra

Parkinson's disease (P.D.) is the second most progressive neurodegenerative disorder in the elderly. Degeneration of dopaminergic (DA) neurons and α-synuclein (α-Syn) accumulated toxicity is the major contributor to this disease. At present, the disease has no effective treatment. Many recent studies focus on identifying novel therapeutics that provide benefits to stop the disease progression in P.D. patients. Screening novel and effective drugs in P.D. animal models is time- and cost-consuming. Rose Essential Oil (REO) extracted from Rosa Rugosa species (R. Setate × R. Rugosa). REO contains Citronellol, Geraniol, and Octadiene that possess anti-Aβ, anti-oxidative, and anti-depression-like properties, but no reports have defined the REO effect on P.D. yet. The present study examines the REO neuroprotective potential in transgenic Caenorhabditis elegans P.D. models. We observed that REO reduced α-Syn aggregations and diminished DA neuron degenerations induced by 6-OHDA, reduced food-sensing behavioural disabilities, and prolonged the lifespan of the nematode. Moreover, REO augmented the chymotrypsin-like proteasome and SOD-3 activities. Further, we observed the anti-oxidative role of REO by reducing internal cells ROS. Together, these findings supported REO as an anti-PD drug and may exert its effects by lowering oxidative stress via the anti-oxidative pathway.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Nerve Degeneration; Oils, Volatile; Parkinson Disease; Rosa

Parkinson's disease (PD) belongs to an α-synucleinopathy and manifests motor dysfunction attributed to nigrostriatal dopaminergic degeneration. In clinical practice, the beneficial role of physical therapy such as motor skill learning training has been recognized in PD-linked motor defects. Nevertheless, the disease-modifying effects of motor skill learning training on PD-related pathology remain unclear. Here, we investigated the disease-modifying effects of rotarod walking exercise (RWE), a modality of motor skill learning training, in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. In motor function and dopaminergic degeneration, RWE improved MPTP-induced deficits. In addition, RWE enhanced the expression of neurotrophic factors BDNF/GDNF, PGC1-α, Nurr1, and p-AMPK, thereby recovering dopaminergic neuronal cell death. Moreover, RWE inhibited microglial activation and the expression of pro-inflammatory markers, such as p-IκBα, iNOS, IL-1β, TNF-α, and cathepsin D, while elevating anti-inflammatory IL-10 and TGF-β. RWE also decreased oxidative stress markers in the substantia nigra, such as 4-HNE and 8-OHdG-positive cells, while increasing Nrf2-controlled antioxidant enzymes. Regarding the effect of RWE on α-synuclein, it reduced the monomer/oligomer forms of α-synuclein and phosphorylation at serine 129. Further mechanistic studies revealed that RWE suppressed the expression of matrix metalloproteinase-3 and p-GSK3β (Y216), which play key roles in α-synuclein aggregation. These data collectively suggest that inhibition of neuroinflammation and α-synuclein oligomerization by RWE may contribute to the improvement of PD pathology.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Mice; Mice, Inbred C57BL; Neuroinflammatory Diseases; Parkinson Disease; Substantia Nigra; Walking

Neuroinflammation has been suggested as a pathogenetic mechanism contributing to Parkinson's disease (PD). However, anti-inflammatory treatment strategies have not yet been established as a therapeutic option for PD patients. We have used a human α-synuclein mouse model of progressive PD to examine the anti-inflammatory and neuroprotective effects of inflammasome inhibition on dopaminergic (DA) neurons in the substantia nigra (SN). As the NLRP3 (NOD-, LRR- and pyrin domain-containing 3)-inflammasome is a core interface for both adaptive and innate inflammation and is also highly druggable, we investigated the implications of its inhibition. Repeat administration of MCC950, an inhibitor of NLRP3, in a PD model with ongoing pathology reduced CD4

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Inflammasomes; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Microglia; Neuroinflammatory Diseases; NLR Family, Pyrin Domain-Containing 3 Protein; Parkinson Disease; Sulfonamides

Progressive neurodegenerative disorders such as Parkinson Disease (PD) lack curative or long-term treatments. At the same time, the increase of the worldwide elderly population and, consequently, the extension in the prevalence of age-related diseases have promoted research interest in neurodegenerative disorders. Caenorhabditis elegans is a free-living nematode widely used as an animal model in studies of human diseases. Here we evaluated cannabidiol (CBD) as a possible neuroprotective compound in PD using the C. elegans models exposed to reserpine. Our results demonstrated that CBD reversed the reserpine-induced locomotor alterations and this response was independent of the NPR-19 receptors, an orthologous receptor for central cannabinoid receptor type 1. Morphological alterations of cephalic sensilla (CEP) dopaminergic neurons indicated that CBD also protects neurons from reserpine-induced degeneration. That is, CBD attenuates the reserpine-induced increase of worms with shrunken soma and dendrites loss, increasing the number of worms with intact CEP neurons. Finally, we found that CBD also reduced ROS formation and α-syn protein accumulation in mutant worms. Our findings collectively provide new evidence that CBD acts as neuroprotector in dopaminergic neurons, reducing neurotoxicity and α-syn accumulation highlighting its potential in the treatment of PD.

Topics: Aged; alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cannabidiol; Disease Models, Animal; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Neuroprotective Agents; Parkinson Disease; Receptors, G-Protein-Coupled; Reserpine

Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by motor and non-motor symptoms. Epidemiological reports showed a significant association between environmental toxicants-induced gut dysbiosis and PD. Neuroinflammation, mitochondrial dysfunction and decreased cerebral blood flow are hallmarks of PD. This study sought to evaluate the protective ability of vinpocetine (VIN), a neuroprotectant, on rotenone (ROT) (mitochondrial complex I inhibitor) induced PD in rats. Sixty male Sprague Dawley rats were randomly divided into six groups (n = 10) and treated orally as follows; group 1: vehicle (10 ml/kg); group 2: rotenone (10 mg/kg) + vehicle; group 3-5: vinpocetine (5, 10 or 20 mg/kg) + rotenone (10 mg/kg), respectively, or group 6: vinpocetine 20 mg/kg before behavioural assay for motor symptoms (fore-limb hanging test and open field test) and non-motor symptoms (working memory and learning capabilities in Y-maze/Morris water maze tasks, anxiety in hole board test and gut motility with intestinal transit time). Following treatment for 28 days, biochemical assays and immunostaining was performed. We examined the effect of vinpocetine on rotenone-induced oxidative stress and inflammatory markers. The pretreatment of rats with vinpocetine reversed rotenone-induced locomotor deficit, motor incoordination, cognition deficits and gut dysfunction. In addition, rotenone-induced a significant increase in the level of interleukin-6 and tumor necrotic factor-α, oxidative stress markers, cholinergic signalling, gut dysfunction and haematologic dysfunctions which were attenuated by vinpocetine administration. Immunostainings showed that rotenone-induced dopamine neuron loss, microglia reactivity, astrocytes activation, toll-like receptor 4 (TLR4) and α-synuclein (SNCA) expressions which were attenuated by vinpocetine administration. Findings from this study revealed a neuroprotective effect of vinpocetine on rotenone-induced PD through anti-neuroinflammatory and antioxidant mechanisms.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Male; Neurodegenerative Diseases; Neuroinflammatory Diseases; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Rats; Rats, Sprague-Dawley; Rotenone

Parkinson's disease (PD) is a chronic and ongoing neurological condition. Unfortunately, as the dopaminergic terminals continue to deteriorate, the effectiveness of anti-Parkinson therapy decreases. This study aimed to examine the effects of BM-MSCs-derived exosomes in rats induced with Parkinson's disease. The goal was to determine their potential for neurogenic repair and functional restoration. Forty male albino rats were divided into four groups: control (group I), PD (group II), PD-L-Dopa (group III), and PD-exosome (group IV). Motor tests, histopathological examinations, and immunohistochemistry for tyrosine hydroxylase were performed on brain tissue. The levels of α-synuclein, DJ-1, PARKIN, circRNA.2837, and microRNA-34b were measured in brain homogenates. Rotenone induced motor deficits and neuronal alterations. Groups (III) and (IV) showed improvement in motor function, histopathology, α-synuclein, PARKIN, and DJ-1 compared to group (II). Group (IV) showed improvement in microRNA-34b and circRNA.2837 compared to groups (III) and (II). MSC-derived exosomes showed a greater suppression of neurodegenerative disease (ND) compared to L-Dopa in Parkinson's patients.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Exosomes; Humans; Levodopa; Male; Mesenchymal Stem Cells; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; Rats; RNA, Circular; Ubiquitin-Protein Ligases

Venglustat is a brain-penetrant, small molecule inhibitor of glucosylceramide synthase used in clinical testing for treatment of Parkinson's disease (PD). Despite beneficial effects in certain cellular and rodent models, patients with PD with mutations in GBA, the gene for lysosomal glucocerebrosidase, experienced worsening of their motor function under venglustat treatment (NCT02906020, MOVES-PD, phase 2 trial).. The objective of this study was to evaluate venglustat in mouse models of PD with overexpression of wild-type α-synuclein.. Mice overexpressing α-synuclein (Thy1-aSyn line 61) or Gba-mutated mice with viral vector-induced overexpression of α-synuclein in the substantia nigra were administered venglustat as food admixture. Motor and cognitive performance, α-synuclein-related pathology, and microgliosis were compared with untreated controls.. Venglustat worsened motor function in Thy1-aSyn transgenics on the challenging beam and the pole test. Although venglustat did not alter the cognitive deficit in the Y-maze test, it alleviated anxiety-related behavior in the novel object recognition test. Venglustat reduced soluble and membrane-bound α-synuclein in the striatum and phosphorylated α-synuclein in limbic brain regions. Although venglustat reversed the loss of parvalbumin immunoreactivity in the basolateral amygdala, it tended to increase microgliosis and phosphorylated α-synuclein in the substantia nigra. Furthermore, venglustat also partially worsened motor performance and tended to increase neurofilament light chain in the cerebrospinal fluid in the Gba-deficient model with nigral α-synuclein overexpression and neurodegeneration.. Venglustat treatment in two mouse models of α-synuclein overexpression showed that glucosylceramide synthase inhibition had differential detrimental or beneficial effects on behavior and neuropathology possibly related to brain region-specific effects. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Transgenic; Parkinson Disease; Substantia Nigra; Synucleinopathies

Parkinson's disease (PD) is characterized by dopaminergic (DAergic) neuronal loss in the substantia nigra pars compacta (SNpc), resulting from α-synuclein (αSyn) toxicity. We previously reported that αSyn oligomerization and toxicity are regulated by the fatty-acid binding protein 3 (FABP3), and the therapeutic effects of the FABP3 ligand, MF1, was successfully demonstrated in PD models. Here, we developed a novel and potent ligand, HY-11-9, which has a higher affinity for FABP3 (Kd = 11.7 ± 8.8) than MF1 (Kd = 302.8 ± 130.3). We also investigated whether the FABP3 ligand can ameliorate neuropathological deterioration after the onset of disease in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism. Motor deficits were observed two weeks after MPTP treatment. Notably, oral administration of HY-11-9 (0.03 mg/kg) improved motor deficits in both beam-walking and rotarod tasks, whereas MF1 failed to improve the motor deficits in both tasks. Consistent with the behavioral tasks, HY-11-9 recovered dopamine neurons from MPTP toxicity in the substantia nigra and ventral tegmental areas. Furthermore, HY-11-9 reduced the accumulation of phosphorylated-serine129-α-synuclein (pS129-αSyn) and colocalization with FABP3 in tyrosine hydroxylase (TH)-positive DA neurons in the PD mouse model. Overall, HY-11-9 significantly improved MPTP-induced behavioral and neuropathological deterioration, suggesting that it may be a potential candidate for PD therapy.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Fatty Acid Binding Protein 3; Ligands; Mice; Mice, Inbred C57BL; MPTP Poisoning; Parkinson Disease; Parkinsonian Disorders; Substantia Nigra

Multiple system atrophy (MSA) is a sporadic adult-onset rare neurodegenerative synucleinopathy for which counteracting central nervous system insulin resistance bears the potential of being neuroprotective. G-protein-(heterotrimeric guanine nucleotide-binding protein)-coupled receptor kinase 2 (GRK2) is emerging as a physiologically relevant inhibitor of insulin signaling.. We tested whether lowering brain GRK2 abundance may reverse insulin-resistance.. We lowered brain GRK2 abundance through viral-mediated delivery of a GRK2-specific miRNA and quantified the reversion of a developing or an established insulin-resistant phenotype using the transgenic PLP-SYN mouse model of MSA.. Viral vector delivery of a GRK2 miRNA demonstrated a neuroprotective capacity when administered (1) in utero intracerebroventricularly in developing PLP-SYN mice and (2) intrastriatally in adult PLP-SYN mice. Decreased striatal GRK2 levels correlated in both designs with neuroprotection of the substantia nigra dopamine neurons, reduction in high-molecular-weight species of α-synuclein, and reduced insulin resistance.. These data support GRK2 as a potential therapeutic target in MSA. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Insulin Resistance; Insulins; Mice; Mice, Transgenic; MicroRNAs; Movement Disorders; Multiple System Atrophy

The study was designed to investigate the pathogenesis of gastrointestinal (GI) impairment in Parkinson's disease (PD). We utilized 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 20 mg/kg) and probenecid (250 mg/kg) to prepare a PD mice model. MPTP modeling was first confirmed. GI motility was measured using stool collection test and enteric plexus loss was also detected. Intestinal phosphorylated α-synuclein (p-α-syn), inflammation, and S100 were assessed using western blotting. Association between Toll-like receptor 2(TLR2) and GI function was validated by Pearson's correlations. Immunofluorescence was applied to show co-localizations of intestinal p-α-syn, inflammation, and Schwann cells (SCs). CU-CPT22 (3 mg/kg, a TLR1/TLR2 inhibitor) was adopted then. Success in modeling, damaged GI neuron and function, and activated intestinal p-α-syn, inflammation, and SCs responses were observed in MPTP group, with TLR2 related to GI damage. Increased p-α-syn and inflammatory factors were shown in SCs of myenteron for MPTP mice. Recovered fecal water content and depression of inflammation, p-α-syn deposition, and SCs activity were noticed after TLR2 suppression. The study investigates a novel mechanism of PD GI autonomic dysfunction, demonstrating that p-α-syn accumulation and TLR2 signaling of SCs were involved in disrupted gut homeostasis and treatments targeting TLR2-mediated pathway might be a possible therapy for PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Autonomic Pathways; Disease Models, Animal; Gastrointestinal Diseases; Inflammation; Mice; Mice, Inbred C57BL; Parkinson Disease; Toll-Like Receptor 2

Parkinson's disease (PD) often displays a strong unilateral predominance in arising symptoms. PD is correlated with dopamine neuron (DAN) degeneration in the substantia nigra pars compacta (SNPC), and in many patients, DANs appear to be affected more severely on one hemisphere than the other. The reason for this asymmetric onset is far from being understood.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Drosophila melanogaster; Humans; Nerve Degeneration; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is an incurable movement disorder characterized by dopaminergic cell loss, neuroinflammation, and α-synuclein pathology. Herein, we investigated the therapeutic effects of necrosulfonamide (NSA), a specific inhibitor of mixed lineage kinase domain-like protein (MLKL), in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MLKL is an executor of necroptosis, a programmed cell death pathway that causes inflammation. Repeated administration of NSA resulted in the recovery of impaired motor performance and dopaminergic degeneration. Furthermore, NSA inhibited the phosphorylation, ubiquitylation, and oligomerization of MLKL, all of which are associated with MLKL cell death-inducing activity in dopaminergic cells in the substantia nigra (SN). NSA also inhibited microglial activation and reactive astrogliosis as well as the MPTP-induced expression of proinflammatory molecules such as tumor necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and cystatin F. Furthermore, NSA inhibited α-synuclein oligomerization and phosphorylation in the SN of MPTP-treated mice by inhibiting the activity of glycogen synthase kinase 3β and matrix metalloproteinase-3. In conclusion, NSA has anti-necroptotic, anti-inflammatory, and anti-synucleinopathic effects on PD pathology. Therefore, NSA is a potential therapeutic candidate for PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Inflammation; Mice; Mice, Inbred C57BL; Necroptosis; Neuroinflammatory Diseases; Neuroprotective Agents; Parkinson Disease

Lysosomal dysfunction has been implicated in a number of neurodegenerative diseases such as Parkinson's disease (PD). Various molecular, clinical and genetic studies have highlighted a central role of lysosomal pathways and proteins in the pathogenesis of PD. Within PD pathology the synaptic protein alpha-synuclein (αSyn) converts from a soluble monomer to oligomeric structures and insoluble amyloid fibrils. The aim of this study was to unravel the effect of αSyn aggregates on lysosomal turnover, particularly focusing on lysosomal homeostasis and cathepsins. Since these enzymes have been shown to be directly involved in the lysosomal degradation of αSyn, impairment of their enzymatic capacity has extensive consequences.. We used patient-derived induced pluripotent stem cells and a transgenic mouse model of PD to examine the effect of intracellular αSyn conformers on cell homeostasis and lysosomal function in dopaminergic (DA) neurons by biochemical analyses.. We found impaired lysosomal trafficking of cathepsins in patient-derived DA neurons and mouse models with αSyn aggregation, resulting in reduced proteolytic activity of cathepsins in the lysosome. Using a farnesyltransferase inhibitor, which boosts hydrolase transport via activation of the SNARE protein ykt6, we enhanced the maturation and proteolytic activity of cathepsins and thereby decreased αSyn protein levels.. Our findings demonstrate a strong interplay between αSyn aggregation pathways and function of lysosomal cathepsins. It appears that αSyn directly interferes with the enzymatic function of cathepsins, which might lead to a vicious cycle of impaired αSyn degradation. Lysosomal trafficking of cathepsin D (CTSD), CTSL and CTSB is disrupted when alpha-synuclein (αSyn) is aggregated. This results in a decreased proteolytic activity of cathepsins, which directly mediate αSyn clearance. Boosting the transport of the cathepsins to the lysosome increases their activity and thus contributes to efficient αSyn degradation.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Homeostasis; Mice; Parkinson Disease; Synucleinopathies

Parkinson's disease (PD) is characterized by a progressive degeneration of dopaminergic neurons, which leads to irreversible loss of peripheral motor functions. Death of dopaminergic neurons induces an inflammatory response in microglial cells, which further exacerbates neuronal loss. Reducing inflammation is expected to ameliorate neuronal loss and arrest motor dysfunctions. Because of the contribution of the NLRP3 inflammasome to the inflammatory response in PD, we targeted NLRP3 using the specific inhibitor OLT1177. We evaluated the effectiveness of OLT1177. Treatment with OLT1177. These data suggest that targeting the NLRP3 inflammasome by OLT1177

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Inflammasomes; Mice; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Parkinson Disease

This study aimed to explore the role of SYNJ1 in Parkinson's disease (PD) and its potential as a neuroprotective factor. We found that SYNJ1 was decreased in the SN and striatum of hSNCA*A53T-Tg and MPTP-induced mice compared to normal mice, associated with motor dysfunction, increased α-synuclein and decreased tyrosine hydroxylase. To investigate its neuroprotective effects, SYNJ1 expression was upregulated in the striatum of mice through injection of the rAdV-Synj1 virus into the striatum, which resulted in the rescue of behavioral deficiencies and amelioration of pathological changes. Subsequently, transcriptomic sequencing, bioinformatics analysis and qPCR were conducted in SH-SY5Y cells following SYNJ1 gene knockdown to identify its downstream pathways, which revealed decreased expression of TSP-1 involving extracellular matrix pathways. The virtual protein-protein docking further suggested a potential interaction between the SYNJ1 and TSP-1 proteins. This was followed by the identification of a SYNJ1-dependent TSP-1 expression model in two PD models. The coimmunoprecipitation experiment verified that the interaction between SYNJ1 and TSP-1 was attenuated in 11-month-old hSNCA*A53T-Tg mice compared to normal controls. Our findings suggest that overexpression of SYNJ1 may protect hSNCA*A53T-Tg and MPTP-induced mice by upregulating TSP-1 expression, which is involved in the extracellular matrix pathways. This suggests that SYNJ1 could be a potential therapeutic target for PD, though more research is needed to understand its mechanism.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Neuroblastoma; Neuroprotection; Neuroprotective Agents; Parkinson Disease; Thrombospondin 1

Retinal detachment (RD) refers to the separation between the neuroepithelium and the pigment epithelium layer. It is an important disease leading to irreversible vision damage worldwide, in which photoreceptor cell death plays a major role. α-Synuclein (α-syn) is reportedly involved in numerous mechanisms of neurodegenerative diseases, but the association with photoreceptor damage in RD has not been studied. In this study, elevated transcription levels of α-syn and parthanatos proteins were observed in the vitreous of patients with RD. The expression of α-syn- and parthanatos-related proteins was increased in experimental rat RD, and was involved in the mechanism of photoreceptor damage, which was related to the decreased expression of miR-7a-5p (miR-7). Interestingly, subretinal injection of miR-7 mimic in rats with RD inhibited the expression of retinal α-syn and down-regulated the parthanatos pathway, thereby protecting retinal structure and function. In addition, interference with α-syn in 661W cells decreased the expression of parthanatos death pathway in oxygen and glucose deprivation model. In conclusion, this study demonstrates the presence of parthanatos-related proteins in patients with RD and the role of the miR-7/α-syn/parthanatos pathway in photoreceptor damage in RD.

Topics: alpha-Synuclein; Animals; Apoptosis; Disease Models, Animal; Humans; MicroRNAs; Parthanatos; Photoreceptor Cells; Photoreceptor Cells, Vertebrate; Rats; Retinal Detachment

Alzheimer's disease (AD) cases are often characterized by the pathological accumulation of α-synuclein (α-syn) in addition to amyloid-β (Aβ) and tau hallmarks. The role of α-syn has been extensively studied in synucleinopathy disorders, but less so in AD. Recent studies have shown that α-syn may also play a role in AD and its downregulation may be protective against the toxic effects of Aβ accumulation.. We hypothesized that selectively knocking down α-syn via RNA interference improves the neuropathological and biochemical findings in AD mice.. Here we used amyloid precursor protein transgenic (APP-Tg) mice to model AD and explore pathologic and behavioral phenotypes with knockdown of α-syn using RNA interference. We selectively reduced α-syn levels by stereotaxic bilateral injection of either LV-shRNA α-syn or LV-shRNA-luc (control) into the hippocampus of AD mice.. We found that downregulation of α-syn results in significant reduction in the number of Aβ plaques. In addition, mice treated with LV-shRNA α-syn had amelioration of abnormal microglial activation (Iba1) and astrocytosis (GFAP) phenotypes in AD mice.. Our data suggests a novel link between Aβ and α-syn pathology as well as a new therapeutic angle for targeting AD.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Disease Models, Animal; Hippocampus; Mice; Mice, Transgenic; Plaque, Amyloid; RNA Interference; RNA, Small Interfering; tau Proteins

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor symptoms and neuropathological features, such as loss of dopaminergic neurons in the substantia nigra pars compacta and accumulation of alpha-synuclein (α-Syn). Progranulin (PGRN) is a secreted growth factor that exhibits anti-inflammatory properties and regulates lysosomal function. Although autophagy-lysosome pathway is the main degradative pathway for α-Syn, the molecular mechanistic relationship between PD and PGRN remains unclear. In this study, we investigated the role of PGRN in PD pathology. PGRN protein expression in striatum was increased in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model mice. Intracerebroventricular (i.c.v.) administration of PGRN ameliorated the decrease in expression of tyrosine hydroxylase, a dopaminergic neuron marker, in MPTP-treated mice. Furthermore, i.c.v. administration of PGRN ameliorated 6-hydroxydopamine-induced motor deficits. In SH-SY5Y human neuroblastoma cells, 1-methyl-4-phenylpyridinium ion (MPP

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Lysosomes; Mice; Mice, Inbred C57BL; Neuroblastoma; Parkinson Disease; Progranulins

Parkinson's disease (PD) is the second most frequent age-related neurodegenerative disorder and is characterized by the loss of dopaminergic neurons. Both environmental and genetic aspects are involved in the pathogenesis of PD. Osmotin is a structural and functional homolog of adiponectin, which regulates the phosphorylation of 5' adenosine monophosphate-activated protein kinase (AMPK) via adiponectin receptor 1 (AdipoR1), thus attenuating PD-associated pathology. Therefore, the current study investigated the neuroprotective effects of osmotin using in vitro and in vivo models of PD.. Based on our study, osmotin mitigated MPTP- and α-synuclein-induced motor dysfunction by upregulating the nuclear receptor-related 1 protein (Nurr1) transcription factor and its downstream markers tyrosine hydroxylase (TH), dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2). From a pathological perspective, osmotin ameliorated neuronal cell death and neuroinflammation by regulating the mitogen-activated protein kinase (MAPK) signaling pathway. Additionally, osmotin alleviated the accumulation of α-synuclein by promoting the AMPK/mammalian target of rapamycin (mTOR) autophagy signaling pathway. Finally, in nonmotor symptoms of PD, such as cognitive deficits, osmotin restored synaptic deficits, thereby improving cognitive impairment in MPTP- and α-synuclein-induced mice.. Therefore, our findings indicated that osmotin significantly rescued MPTP/α-synuclein-mediated PD neuropathology. Altogether, these results suggest that osmotin has potential neuroprotective effects in PD neuropathology and may provide opportunities to develop novel therapeutic interventions for the treatment of PD.

Topics: alpha-Synuclein; AMP-Activated Protein Kinases; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Mammals; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinson Disease; Signal Transduction; Substantia Nigra; TOR Serine-Threonine Kinases

The study investigated the effects of ozone treatment on the neurodegeneration of stereotaxic rotenone-induced parkinson's disease (PD) model. The model was confirmed using the apomorphine rotation test. α-synuclein, amyloid-β, Tau, phosphorylated Tau, as well as tyrosine hydroxylase(+), nNOS(+), and glial cell counts were used to evaluate neurodegeneration in the substantia nigra pars compacta and ventral tegmental area. The experiment involved 48 Sprague-Dawley rats divided into four groups: dimethyl sulfoxide (DMSO), DMSO with ozone (O), DMSO/rotenone (R), and D/R/O. Ozone treatment significantly improved tissue α-synuclein level and TH+, nNOS+, and glial cell counts compared to the rotenone-only group. The study suggests that ozone treatment may have beneficial effects on PD biomarkers in the rotenone model. Further studies on ozone dosage, duration, and administration methods in humans could provide more evidence for its potential use in Parkinson's disease treatment.

Topics: alpha-Synuclein; Animals; Dimethyl Sulfoxide; Disease Models, Animal; Humans; Parkinson Disease; Rats; Rats, Sprague-Dawley; Rotenone; Substantia Nigra

To date, there is no cure for Parkinson's disease (PD). There is a pressing need for anti-neurodegenerative therapeutics that can slow or halt PD progression by targeting underlying disease mechanisms. Specifically, preventing the build-up of alpha-synuclein (αSyn) and its aggregated and mutated forms is a key therapeutic target. In this study, an adeno-associated viral vector loaded with the A53T gene mutation was used to induce rapid αSyn-associated PD pathogenesis in C57BL/6 mice. We tested the ability of a novel therapeutic, a single chain fragment variable (scFv) antibody with specificity only for pathologic forms of αSyn, to protect against αSyn-induced neurodegeneration, after unilateral viral vector injection in the substantia nigra. Additionally, polyanhydride nanoparticles, which provide sustained release of therapeutics with dose-sparing properties, were used as a delivery platform for the scFv. Through bi-weekly behavioral assessments and across multiple post-mortem immunochemical analyses, we found that the scFv-based therapies allowed the mice to recover motor activity and reduce overall αSyn expression in the substantia nigra. In summary, these novel scFv-based therapies, which are specific exclusively for pathological aggregates of αSyn, show early promise in blocking PD progression in a surrogate mouse PD model.

Topics: alpha-Synuclein; Animals; Antibodies; Autopsy; Disease Models, Animal; Mice; Mice, Inbred C57BL; Parkinson Disease

Parkinson's disease (PD) is a neurodegenerative disease caused by loss of dopaminergic neurons in the substantia nigra and it is known to involve the accumulation of α-synuclein (α-syn), which is a neuroprotein that promotes degeneration of dopaminergic neurons. Serum/glucocorticoid-related kinase 1 (SGK1) is involved in the physiological and pathological processes in neurons. The aim of this study was to examine the relationship between SGK1 and α-syn expression in muscle tissue of a PD model and in C2C12 cells. Western blotting, immunohistochemistry, and immunofluorescence microscopy confirmed reduced SGK1 and increased α-syn expression in skeletal muscle of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice compared to the control group. To determine the relationship between SGK1 and α-syn, SGK1 small interfering RNA (siRNA) knockdown was performed in C2C12 cells, which showed that suppression of SGK1 levels resulted in increased α-syn expression. The main finding of our study is that reduction of SGK1 expression contributes to the pathogenesis of PD by increasing the expression of α-syn in skeletal muscle of MPTP-treated mice and C2C12 cells. This study confirms that decreased SGK1 induces increased α-syn expression in skeletal muscle, which suggests that maintaining SGK1 expression may improve PD symptoms.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Glucocorticoids; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Neurodegenerative Diseases; Parkinson Disease; Substantia Nigra

Evidence supports a role for the gut-brain axis in Parkinson's disease (PD). Mice overexpressing human wild type α- synuclein (Thy1-haSyn) exhibit slow colonic transit prior to motor deficits, mirroring prodromal constipation in PD. Identifying molecular changes in the gut could provide both biomarkers for early diagnosis and gut-targeted therapies to prevent progression.. To identify early molecular changes in the gut-brain axis in Thy1-haSyn mice through gene expression profiling.. Gene expression profiling was performed on gut (colon) and brain (striatal) tissue from Thy1-haSyn and wild-type (WT) mice aged 1 and 3 months using 3' RNA sequencing. Analysis included differential expression, gene set enrichment and weighted gene co-expression network analysis (WGCNA).. At one month, differential expression (Thy1-haSyn vs. WT) of mitochondrial genes and pathways related to PD was discordant between gut and brain, with negative enrichment in brain (enriched in WT) but positive enrichment in gut. Linear regression of WGCNA modules showed partial independence of gut and brain gene expression changes. Thy1-haSyn-associated WGCNA modules in the gut were enriched for PD risk genes and PD-relevant pathways including inflammation, autophagy, and oxidative stress. Changes in gene expression were modest at 3 months.. Overexpression of haSyn acutely disrupts gene expression in the colon. While changes in colon gene expression are highly related to known PD-relevant mechanisms, they are distinct from brain changes, and in some cases, opposite in direction. These findings are in line with the emerging view of PD as a multi-system disease.

Topics: alpha-Synuclein; Animals; Colon; Disease Models, Animal; Gene Expression; Humans; Mice; Mice, Transgenic; Parkinson Disease

Neurodegenerative disorders of aging are characterized by the progressive accumulation of proteins such as α-synuclein (α-syn) and amyloid beta (Aβ). Misfolded and aggregated α-syn has been implicated in neurological disorders such as Parkinson's disease, and Dementia with Lewy Bodies, but less so in Alzheimer's Disease (AD), despite the fact that accumulation of α-syn has been confirmed in over 50% of postmortem brains neuropathologically diagnosed with AD. To date, no therapeutic strategy has effectively or consistently downregulated α-syn in AD. Here we tested the hypothesis that by using a systemically-delivered peptide (ApoB

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Apolipoproteins B; Disease Models, Animal; Mice; Oligonucleotides, Antisense

Oxidative stress-mediated damage is often a downstream result of Parkinson's disease (PD), which is marked by sharp decline in dopaminergic neurons within the nigrostriatal regions of the brain, accounting for the symptomatic motor deficits in patients. Regulating the level of oxidative stress may present a beneficial approach in preventing PD pathology. Here, we assessed the efficacy of a nicotinamide adenine phosphate (NADPH) oxidase (NOX) inhibitor, an exogenous reactive oxygen species (ROS) regulator synthesized by Aptabio therapeutics with the specificity to NOX-1, 2 and 4. Utilizing N27 rat dopaminergic cells and C57Bl/6 mice, we confirmed that the exposures of alpha-synuclein preformed fibrils (PFF) induced protein aggregation, a hallmark in PD pathology. In vitro assessment of the novel compound revealed an increase in cell viability and decreases in cytotoxicity, ROS, and protein aggregation (Thioflavin-T stain) against PFF exposure at the optimal concentration of 10 nM. Concomitantly, the oral treatment alleviated motor-deficits in behavioral tests, such as hindlimb clasping, rotarod, pole, nesting and grooming test, via reducing protein aggregation, based on rescued dopaminergic neuronal loss. The suppression of NOX-1, 2 and 4 within the striatum and ventral midbrain regions including Substantia Nigra compacta (SNc) contributed to neuroprotective/recovery effects, making it a potential therapeutic option for PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Inbred C57BL; Parkinson Disease; Pars Compacta; Protein Aggregates; Rats; Reactive Oxygen Species

Non-motor symptoms in Parkinson's disease (PD) are common, difficult to treat, and significantly impair quality of life. One prevalent non-motor symptom is constipation, which can precede the diagnosis of PD by years or even decades. Constipation has been underexplored in animal models of PD and lacks specific therapies. This assay utilizes a Drosophila model of PD in which human alpha-synuclein is expressed under a pan-neuronal driver. Flies expressing alpha-synuclein develop the hallmark features of PD: the loss of dopaminergic neurons, motor impairment, and alpha-synuclein inclusions. This protocol outlines a method for studying constipation in these flies. Flies are placed on fly food with a blue color additive overnight and then transferred to standard food the following day. They are subsequently moved to new vials with standard fly food every hour for 8 h. Before each transfer, the percentage of blue-colored fecal spots compared to the total fecal spots on the vial wall is calculated. Control flies that lack alpha-synuclein expel all the blue dye hours before flies expressing alpha-synuclein. Additionally, the passage of blue-colored food from the gut can be monitored with simple photography. The simplicity of this assay enables its use in forward genetic or chemical screens to identify modifiers of constipation in Drosophila.

Topics: alpha-Synuclein; Animals; Constipation; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Humans; Parkinson Disease; Quality of Life

Parkinson's disease (PD) is a long-term neurodegenerative disease characterized by dopaminergic neuronal loss and the aggregation of alpha-synuclein (α-syn) in the brain. Cell therapy using regulatory T cells (Tregs) has therapeutic potential on PD progression in a mouse model; however, several challenges were associated with its applications. Here, we propose a strategy for α-syn specific Treg expansion (α-syn Treg). We presented α-syn to T cells via dendritic cells. This method increased the mobility of Tregs towards the site of abundant α-syn in vitro (

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Parkinson Disease; T-Lymphocytes, Regulatory

The aggregation of misfolded proteins, such as α-synuclein in Parkinson's disease (PD), occurs intracellularly or extracellularly in the majority of neurodegenerative diseases. The immunoproteasome has more potent chymotrypsin-like activity than normal proteasome. Thus, degradation of α-synuclein aggregation via immunoproteasome is an attractive approach for PD drug development. Herein, we aimed to determine if novel compound, 11-Hydroxy-1-(8-methoxy-5-(trifluoromethyl)quinolin-2-yl)undecan-1-one oxime (named as J24335), is a promising candidate for disease-modifying therapy to prevent the pathological progression of neurodegenerative diseases, such as PD. The effects of J24335 on inducible PC12/A53T-α-syn cell viability and cytotoxicity were evaluated by MTT assay and LDH assay, respectively. Evaluation of various proteasome activities was done by measuring the luminescence of enzymatic activity after the addition of different amounts of aminoluciferin. Immunoblotting and real-time PCR were employed to detect the expression of various proteins and genes, respectively. We also used a transgenic mouse model for behavioral testing and immunochemical analysis, to assess the neuroprotective effects of J24335. J24335 inhibited wild-type and mutant α-synuclein aggregation without affecting the growth or death of neuronal cells. The inhibition of α-synuclein aggregation by J24335 was caused by activation of immunoproteasome, as mediated by upregulation of LMP7, and increased cellular chymotrypsin-like activity in 20S proteasome. J24335-enhanced immunoproteasome activity was mediated by PKA/Akt/mTOR pathway activation. Moreover, animal studies revealed that J24335 treatment markedly mitigated both the loss of tyrosine hydroxylase-positive (TH-) neurons and impaired motor skill development. This is the first report to use J24335 as an immunoproteasome enhancing agent to antagonize pathological α-synuclein-mediated neurodegeneration.

Topics: alpha-Synuclein; Animals; Chymotrypsin; Disease Models, Animal; Mice; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease; Proteasome Endopeptidase Complex

Anethole is the main compound of the essential oil of anise and several other plants, which has antioxidant, anti-inflammatory, and neuroprotective properties. Oxidative stress is considered as an important factor in the pathogenesis of PD. In the present study, we aimed to investigate the effects of anethole against rotenone-induced PD.. Male Wistar rats were randomly divided into six groups. Control group received DMSO + sunflower oil, model group received rotenone (2 mg/kg, s.c, daily for 35 days), positive control group received L-Dopa, and test groups received anethole (62.5, 125, and 250 mg/kg, i.g, daily for 35 days) 1 hour before each rotenone injection. Body weight changes, rotarod test, stride length test, and extracellular single unit recording were performed after treatment. After behavioral test, Brain water content and blood brain barrier (BBB) permeability were evaluated, and the levels of malondialdehyde (MDA), superoxide dismutases (SOD), alpha-synuclein and MAO-B were measured in the striatum.. Chronic administration of rotenone induced body weight loss and caused significant dysfunction in locomotor activity, neuronl firing rate, and BBB. Rotenone also decreased SOD activity, increased MDA level, and elevated the expression of alpha-synuclein and MAO-B in the striatum. However, treatment with anethole attenuated body weight loss, motor function, neuronal activity, and BBB function. Furthermore, Anethole treatment attenuated oxidative stress and decreased the expression of alpha-synuclein and MAO-B compared to the rotenone group.. Our results show that through its antioxidant properties, aethole can improve the cellular, molecular and behavioral characteristics of rotenone-induced Parkinson's disease.

Topics: alpha-Synuclein; Animals; Antioxidants; Blood-Brain Barrier; Disease Models, Animal; Monoamine Oxidase; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Rats; Rats, Wistar; Rotenone; Superoxide Dismutase; Weight Loss

Inflammation in the brain and gut is a critical component of several neurological diseases, such as Parkinson's disease (PD). One trigger of the immune system in PD is aggregation of the pre-synaptic protein, α-synuclein (αSyn). Understanding the mechanism of propagation of αSyn aggregates is essential to developing disease-modifying therapeutics. Using a brain-first mouse model of PD, we demonstrate αSyn trafficking from the brain to the ileum of male mice. Immunohistochemistry revealed that the ileal αSyn aggregations are contained within CD11c

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Ileum; Male; Mice; Parkinson Disease

Alpha-synuclein (α-syn) aggregation into proteinaceous intraneuronal inclusions, called Lewy bodies (LBs), is the neuropathological hallmark of Parkinson's disease (PD) and related synucleinopathies. However, the exact role of α-syn inclusions in PD pathogenesis remains elusive. This lack of knowledge is mainly due to the absence of optimal α-syn-based animal models that recapitulate the different stages of neurodegeneration.. Here we describe a novel approach for a systemic delivery of viral particles carrying human α-syn allowing for a large-scale overexpression of this protein in the mouse brain. This approach is based on the use of a new generation of adeno-associated virus (AAV), AAV-PHP.eB, with an increased capacity to cross the blood-brain barrier, thus offering a viable tool for a non-invasive and large-scale gene delivery in the central nervous system.. Using this model, we report that widespread overexpression of human α-syn induced selective degeneration of dopaminergic (DA) neurons, an exacerbated neuroinflammatory response in the substantia nigra and a progressive manifestation of PD-like motor impairments. Interestingly, biochemical analysis revealed the presence of insoluble α-syn oligomers in the midbrain. Together, our data demonstrate that a single non-invasive systemic delivery of viral particles overexpressing α-syn prompted selective and progressive neuropathology resembling the early stages of PD.. Our new in vivo model represents a valuable tool to study the role of α-syn in PD pathogenesis and in the selective vulnerability of nigral DA neurons; and offers the opportunity to test new strategies targeting α-syn toxicity for the development of disease-modifying therapies for PD and related disorders.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopaminergic Neurons; Humans; Lewy Bodies; Mice; Parkinson Disease; Rodentia; Substantia Nigra

Pathologic α-synuclein plays an important role in the pathogenesis of α-synucleinopathies such as Parkinson's disease (PD). Disruption of proteostasis is thought to be central to pathologic α-synuclein toxicity; however, the molecular mechanism of this deregulation is poorly understood. Complementary proteomic approaches in cellular and animal models of PD were used to identify and characterize the pathologic α-synuclein interactome. We report that the highest biological processes that interacted with pathologic α-synuclein in mice included RNA processing and translation initiation. Regulation of catabolic processes that include autophagy were also identified. Pathologic α-synuclein was found to bind with the tuberous sclerosis protein 2 (TSC2) and to trigger the activation of the mammalian target of rapamycin (mTOR) complex 1 (mTORC1), which augmented mRNA translation and protein synthesis, leading to neurodegeneration. Genetic and pharmacologic inhibition of mTOR and protein synthesis rescued the dopamine neuron loss, behavioral deficits, and aberrant biochemical signaling in the α-synuclein preformed fibril mouse model and

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mammals; Mechanistic Target of Rapamycin Complex 1; Mice; Parkinson Disease; Proteomics; TOR Serine-Threonine Kinases

Parkinson's disease (PD), one of the most devastating neurodegenerative brain disorders, is characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN) and deposits of α-synuclein aggregates. Currently, pharmacological interventions for PD remain inadequate. The cell necroptosis executor protein MLKL (Mixed-lineage kinase domain-like) is involved in various diseases, including inflammatory bowel disease and neurodegenerative diseases; however, its precise role in PD remains unclear. Here, we investigated the neuroprotective role of MLKL inhibition or ablation against primary neuronal cells and human iPSC-derived midbrain organoids induced by toxic α-Synuclein preformed fibrils (PFFs). Using a mouse model (Tg-Mlkl

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Knockout; Mice, Transgenic; Neuroinflammatory Diseases; Parkinson Disease; Protein Kinases; Substantia Nigra

Lewy bodies are characteristic spherical inclusions in Parkinson's disease (PD) that are formed by α-synuclein fibrils. Ferruginol (Fer) is an amonomeric compound isolated from a traditional Chinese herb. Here, we show that Fer exerted potent neuroprotective effects in both in vitro and in vivo PD models. Neuronal cells transfected with A53T mutant (A53T) α-synuclein plasmids and treated with Fer exhibited attenuated the cytotoxicity induced by pathogenic A53T α-synuclein overexpression. Further, when we transfected neuronal cells with siRNA-SNCA (alpha-synuclein) plasmids and incubated them with Fer, the protective role of Fer decreased. We also found that Fer was a potent α-synuclein inhibitor in neuronal cells, which promotes the clearance of αsynuclein in dopaminergic neurons exposed to 1-Methyl-4-phenylpyridinium (MPP +). Fer could inhibit abnormal α-synuclein aggregation and dopaminergic neuron depletion in A53T-Tg mice, suggesting that a role for Fer in α-synuclein accumulation and nigrostriatal pathway injury. Our study revealed that Fer strongly alleviated neurodegeneration by promoting α-synuclein clearance, indicating a neuroprotective role against α-synuclein oligomer-induced neurodegeneration, which makes it a promising candidate for the treatment of PD and other neurodegenerative diseases.

Topics: Abietanes; alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Medicine, Chinese Traditional; Mice; Neurons; Neuroprotective Agents; Parkinson Disease; Plant Extracts

Several degenerative brain disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) are characterized by the simultaneous appearance of amyloid-β (Aβ) and α-synuclein (α-syn) pathologies and symptoms that are similar, making it difficult to differentiate between these diseases. Until now, an accurate diagnosis can only be made by postmortem analysis. Furthermore, the role of α-syn in Aβ aggregation and the arising characteristic olfactory impairments observed during the progression of these diseases is still not well understood. Therefore, we assessed Aβ load in olfactory bulbs of APP-transgenic mice expressing APP695

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Disease Models, Animal; Mice; Mice, Transgenic; Olfactory Bulb; Synucleinopathies

Alpha synuclein has a key role in the pathogenesis of Parkinson's disease (PD), Dementia with Lewy Bodies (LBD) and Multiple System Atrophy (MSA). Immunotherapies aiming at neutralising toxic αSyn species are being investigated in the clinic as potential disease modifying therapies for PD and other synucleinopathies. In this study, the effects of active immunisation against αSyn with the UB-312 vaccine were investigated in the Thy1SNCA/15 mouse model of PD. Young transgenic and wild-type mice received an immunisation regimen over a period of 6 weeks, then observed for an additional 9 weeks. Behavioural assessment was conducted before immunisation and at 15 weeks after the first dose. UB-312 immunisation prevented the development of motor impairment in the wire test and challenging beam test, which was associated with reduced levels of αSyn oligomers in the cerebral cortex, hippocampus and striatum of Thy1SNCA/15 mice. UB-312 immunotherapy resulted in a significant reduction of theαSyn load in the colon, accompanied by a reduction in enteric glial cell reactivity in the colonic ganglia. Our results demonstrate that immunisation with UB-312 prevents functional deficits and both central and peripheral pathology in Thy1SNCA/15 mice.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Intestines; Mice; Mice, Transgenic; Parkinsonian Disorders; Protein Aggregation, Pathological; Vaccination; Vaccines, Subunit

An elevation in iron levels, together with an accumulation of α-synuclein within the oligodendrocytes, are features of the rare atypical parkinsonian disorder, Multiple System Atrophy (MSA). We have previously tested the novel compound ATH434 (formally called PBT434) in preclinical models of Parkinson's disease and shown that it is brain-penetrant, reduces iron accumulation and iron-mediated redox activity, provides neuroprotection, inhibits alpha synuclein aggregation and lowers the tissue levels of alpha synuclein. The compound was also well-tolerated in a first-in-human oral dosing study in healthy and older volunteers with a favorable, dose-dependent pharmacokinetic profile.. To evaluate the efficacy of ATH434 in a mouse MSA model.. The PLP-α-syn transgenic mouse overexpresses α-synuclein, demonstrates oligodendroglial pathology, and manifests motor and non-motor aspects of MSA. Animals were provided ATH434 (3, 10, or 30 mg/kg/day spiked into their food) or control food for 4 months starting at 12 months of age and were culled at 16 months. Western blot was used to assess oligomeric and urea soluble α-synuclein levels in brain homogenates, whilst stereology was used to quantitate the number of nigral neurons and glial cell inclusions (GCIs) present in the substantia nigra pars compacta.. ATH434 reduced oligomeric and urea soluble α-synuclein aggregation, reduced the number of GCIs, and preserved SNpc neurons. In vitro experiments suggest that ATH434 prevents the formation of toxic oligomeric "species of synuclein".. ATH434 is a promising small molecule drug candidate that has potential to move forward to trial for treating MSA.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Iron; Mice; Mice, Transgenic; Multiple System Atrophy; Parkinson Disease; Urea

Prolonged inflammation, oxidative stress, and protein aggregation are important factors contributing to Parkinson's disease (PD) pathology. A known ROS generator, pesticide paraquat (PQ), was indicated as an environmental substance potentially increasing the incidence of PD and is used to model this disease. We investigated if a combination of inflammation and oxidative stress in subthreshold doses would exacerbate the modelled neuropathology.. We examined the late effects of acute or repeated peripheral inflammation induced by low dose of LPS (10 μg/kg, ip) on PQ toxicity in the rat nigrostriatal dopaminergic pathway, microglial activation markers and expression of major Lewy bodies proteins, α-synuclein and synphilin-1.. We observed that LPS increased, while PQ decreased body temperature and microglia CD11b expression in the SN. Single LPS pretreatment, 3 h before repeated weekly PQ injections (4×) slightly aggravated neuronal degeneration in the SN. Moreover, degeneration of dopaminergic neurons after weekly repeated inflammation itself (4×) was observed. Interestingly, repeated LPS administration combined with each PQ dose counteracted such effect. The expression of α-synuclein decreased after repeated LPS injections, while only combined, repeated LPS and PQ treatment lowered the levels of synphilin-1. Therefore, α-synuclein and synphilin-1 expression change was influenced by different mechanisms. Concomitantly, decreased levels of the two proteins correlated with decreased degeneration of dopaminergic neurons and with a normalized microglia activation marker.. Our results indicate that both oxidative insult triggered by PQ and inflammation caused by peripheral LPS injection can individually induce neurotoxicity. Those factors act through different mechanisms that are not additive and not selective towards dopaminergic neurons, probably implying microglia. Repeated, but small insults from oxidative stress and inflammation when administered in significant time intervals can counteract each other and even act protective as a preconditioning effect. The timing of such repetitive insults is also of essence.

Topics: alpha-Synuclein; Animals; Carrier Proteins; Disease Models, Animal; Dopaminergic Neurons; Dose-Response Relationship, Drug; Environmental Exposure; Herbicides; Inflammation; Lipopolysaccharides; Microglia; Nerve Tissue Proteins; Neurotoxicity Syndromes; Oxidative Stress; Paraquat; Parkinson Disease; Protective Agents; Rats; Substantia Nigra

Epidemiologically Parkinson's disease (PD) is associated with chronic ingestion or inhalation of environmental toxins leading to the development of motor symptoms. Though neurotoxin-based animal models played a major role in understanding diverse pathogenesis, they failed to identify the risk assessment due to uncommon route of toxin exposure. Towards this, the available neurotoxin-based intranasal (i.n.) PD models targeting olfactory bulb (OB) have demonstrated the dopaminergic (DAergic) neurodegeneration in both OB and substantia nigra (SN). Despite that, the studies detecting the alpha-synuclein (α-syn) accumulation in OB and its progression to other brain regions due to inhalation of environmental toxins are still lacking. Herein, we developed oil in water microemulsion of rotenone administered intranasally to the mice at a dose which is not detectable in blood, brain, and olfactory bulb by LCMS method. Our data reveals that 9 weeks of rotenone exposure did not induce olfactory and motor dysfunction. Conversely, after 16 weeks of washout period, rotenone treated mice showed both olfactory and motor impairment, along with α-syn accumulation in the OB and striatum without glial cell activation and loss of dopaminergic neurons. The results depict the progressive nature of the developed model and highlight the role of α-syn in PD like pathology or symptoms. Together, our findings suggest the adverse consequences of early exposure to the environmental toxins on the olfactory system for a shorter period with relevance to the development of synucleinopathy or Parkinson's disease in its later stage.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Mice; Parkinson Disease; Rotenone; Substantia Nigra

Parkinson's disease is a neurodegenerative disease characterized by the formation of neuronal inclusions of α-synuclein in patient brains. As the disease progresses, toxic α-synuclein aggregates transmit throughout the nervous system. No effective disease-modifying therapy has been established, and preventing α-synuclein aggregation is thought to be one of the most promising approaches to ameliorate the disease. In this study, we performed a two-step screening using the thioflavin T assay and a cell-based assay to identify α-synuclein aggregation inhibitors. The first screening, thioflavin T assay, allowed the identification of 30 molecules, among a total of 1262 FDA-approved small compounds, which showed inhibitory effects on α-synuclein fibrilization. In the second screening, a cell-based aggregation assay, seven out of these 30 candidates were found to prevent α-synuclein aggregation without causing substantial toxicity. Of the seven final candidates, tannic acid was the most promising compound. The robustness of our screening method was validated by a primary neuronal cell model and a Caenorhabditis elegans model, which demonstrated the effect of tannic acid against α-synuclein aggregation. In conclusion, our two-step screening system is a powerful method for the identification of α-synuclein aggregation inhibitors, and tannic acid is a promising candidate as a disease-modifying drug for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Benzothiazoles; Biological Assay; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Drug Repositioning; HeLa Cells; High-Throughput Screening Assays; Humans; Mice, Inbred C57BL; Neurons; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; Spectrometry, Fluorescence; Tannins

Accumulation of phosphorylated α-synuclein aggregates has been implicated in several diseases, such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB), and is thought to spread in a prion-like manner. Elucidating the mechanisms of prion-like transmission of α-synuclein is important for the development of therapies for these diseases, but little is known about the details. Here, we injected α-synuclein fibrils into the brains of wild-type mice and examined the early phase of the induction of phosphorylated α-synuclein accumulation. We found that phosphorylated α-synuclein appeared within a few days after the intracerebral injection. It was observed initially in presynaptic regions and subsequently extended its localization to axons and cell bodies.　These results suggest that extracellular α-synuclein fibrils are taken up into the presynaptic region and seed-dependently convert the endogenous normal α-synuclein that is abundant there to an abnormal phosphorylated form, which is then transported through the axon to the cell body.

Topics: alpha-Synuclein; Animals; Axons; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Embryo, Mammalian; Hippocampus; Humans; Male; Mice; Neurodegenerative Diseases; Phosphorylation; Primary Cell Culture; Recombinant Proteins; Synapses

There is increasing preclinical and clinical data supporting a potential association between Traumatic Brain Injury (TBI) and Parkinson's disease (PD). It has been suggested that the glutamate-induced excitotoxicity underlying TBI secondary neuronal degeneration (SND) might be associated with further development of PD. Interestingly, an accumulation of extracellular glutamate and olfactory dysfunction are both sharing pathological conditions in TBI and PD. The possible involvement of glutamate excitotoxicity in olfactory dysfunction has been recently described, however, the role of olfactory bulbs (OB) glutamate excitotoxicity as a possible mechanism involved in the association between TBI and PD-related neurodegeneration has not been investigated yet. We examined the number of nigral dopaminergic neurons (TH +), nigral α-synuclein expression, the striatal dopamine transporter (DAT) expression, and motor performance after bilateral OB N-Methyl-D-Aspartate (NMDA)-induced excitotoxic lesions in rodents. Bulbar NMDA administration induced a decrease in the number of correct choices in the discrimination tests one week after lesions (p < 0.01) and a significant decrease in the number of nigral DAergic neurons (p < 0.01) associated with an increase in α-synuclein expression (p < 0.01). No significant striatal changes in DAT expression or motor alterations were observed. Our results show an association between TBI-induced SND and PD-related neurodegeneration suggesting that the OB excitotoxicity occurring in TBI SND may be a filling gap mechanism underlying the link between TBI and PD-like pathology.

Topics: alpha-Synuclein; Animals; Brain Injuries, Traumatic; Disease Models, Animal; Dopaminergic Neurons; Humans; Olfactory Bulb; Parkinson Disease; Substantia Nigra

Marketed drugs for Parkinson's disease (PD) treat disease motor symptoms but are ineffective in stopping or slowing disease progression. In the quest of novel pharmacological approaches that may target disease progression, drug-repurposing provides a strategy to accelerate the preclinical and clinical testing of drugs already approved for other medical indications. Here, we targeted the inflammatory component of PD pathology, by testing for the first time the disease-modifying properties of the immunomodulatory imide drug (IMiD) pomalidomide in a translational rat model of PD neuropathology based on the intranigral bilateral infusion of toxic preformed oligomers of human α-synuclein (H-αSynOs). The neuroprotective effect of pomalidomide (20 mg/kg; i.p. three times/week 48 h apart) was tested in the first stage of disease progression by means of a chronic two-month administration, starting 1 month after H-αSynOs infusion, when an already ongoing neuroinflammation is observed. The intracerebral infusion of H-αSynOs induced an impairment in motor and coordination performance that was fully rescued by pomalidomide, as assessed via a battery of motor tests three months after infusion. Moreover, H-αSynOs-infused rats displayed a 40-45% cell loss within the bilateral substantia nigra, as measured by stereological counting of TH + and Nissl-stained neurons, that was largely abolished by pomalidomide. The inflammatory response to H-αSynOs infusion and the pomalidomide treatment was evaluated both in CNS affected areas and peripherally in the serum. A reactive microgliosis, measured as the volume occupied by the microglial marker Iba-1, was present in the substantia nigra three months after H-αSynOs infusion as well as after H-αSynOs plus pomalidomide treatment. However, microglia differed for their phenotype among experimental groups. After H-αSynOs infusion, microglia displayed a proinflammatory profile, producing a large amount of the proinflammatory cytokine TNF-α. In contrast, pomalidomide inhibited the TNF-α overproduction and elevated the anti-inflammatory cytokine IL-10. Moreover, the H-αSynOs infusion induced a systemic inflammation with overproduction of serum proinflammatory cytokines and chemokines, that was largely mitigated by pomalidomide. Results provide evidence of the disease modifying potential of pomalidomide in a neuropathological rodent model of PD and support the repurposing of this drug for clinical testing in PD patients.

Topics: alpha-Synuclein; Animals; Cytokines; Disease Models, Animal; Disease Progression; Drug Repositioning; Humans; Microglia; Neuroprotective Agents; Parkinson Disease; Rats; Substantia Nigra; Thalidomide; Tumor Necrosis Factor-alpha

A key pathological process in Parkinson's disease (PD) is the transneuronal spreading of α-synuclein. Alpha-synuclein (α-syn) is a presynaptic protein that, in PD, forms pathological inclusions. Other hallmarks of PD include neurodegeneration and microgliosis in susceptible brain regions. Whether it is primarily transneuronal spreading of α-syn particles, inclusion formation, or other mechanisms, such as inflammation, that cause neurodegeneration in PD is unclear. We used a model of spreading of α-syn induced by striatal injection of α-syn preformed fibrils into the mouse striatum to address this question. We performed quantitative analysis for α-syn inclusions, neurodegeneration, and microgliosis in different brain regions, and generated gene expression profiles of the ventral midbrain, at two different timepoints after disease induction. We observed significant neurodegeneration and microgliosis in brain regions not only with, but also without α-syn inclusions. We also observed prominent microgliosis in injured brain regions that did not correlate with neurodegeneration nor with inclusion load. Using longitudinal gene expression profiling, we observed early gene expression changes, linked to neuroinflammation, that preceded neurodegeneration, indicating an active role of microglia in this process. Altered gene pathways overlapped with those typical of PD. Our observations indicate that α-syn inclusion formation is not the major driver in the early phases of PD-like neurodegeneration, but that microglia, activated by diffusible, oligomeric α-syn, may play a key role in this process. Our findings uncover new features of α-syn induced pathologies, in particular microgliosis, and point to the necessity for a broader view of the process of α-syn spreading.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Microglia; Neuroinflammatory Diseases; Parkinson Disease

Parkinson's disease (PD) is the second most progressive neurodegenerative disorder of the central nervous system in the elderly, causing motor impediments and cognitive dysfunctions. Dopaminergic (DA) neuron degeneration and α-synuclein (α-Syn) accumulation in substantia nigra pars compacta are the major contributors to this disease. At present, PD remains untreatable with a huge burden on the quality of life. Therefore, we attempt to explore novel treatment strategies by detecting effective drugs that stop or arrest PD's progression

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Flavonoids; Parkinson Disease; Quality of Life

α-synuclein (α-syn) aggregation and accumulation drive neurodegeneration in Parkinson's disease (PD). The substantia nigra of patients with PD contains excess iron, yet the underlying mechanism accounting for this iron accumulation is unclear. Here, we show that misfolded α-syn activates microglia, which release interleukin 6 (IL-6). IL-6, via its trans-signaling pathway, induces changes in the neuronal iron transcriptome that promote ferrous iron uptake and decrease cellular iron export via a pathway we term the cellular iron sequestration response, or CISR. The brains of patients with PD exhibit molecular signatures of the IL-6-mediated CISR. Genetic deletion of IL-6, or treatment with the iron chelator deferiprone, reduces pathological α-syn toxicity in a mouse model of sporadic PD. These data suggest that IL-6-induced CISR leads to toxic neuronal iron accumulation, contributing to synuclein-induced neurodegeneration.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Dopaminergic Neurons; Female; Interleukin-6; Iron; Iron Chelating Agents; Male; Mice, Inbred C57BL; Mice, Transgenic; Nerve Degeneration; Neurons; Parkinson Disease; Signal Transduction; Substantia Nigra

Epidemiological studies suggest a link between the melanoma-related pigmentation gene melanocortin 1 receptor (MC1R) and risk of Parkinson's disease (PD). We previously showed that MC1R signaling can facilitate nigrostriatal dopaminergic neuron survival. The present study investigates the neuroprotective potential of MC1R against neurotoxicity induced by alpha-synuclein (αSyn), a key player in PD genetics and pathogenesis.. Nigral dopaminergic neuron toxicity induced by local overexpression of aSyn was assessed in mice that have an inactivating mutation of MC1R, overexpress its wild-type transgene, or were treated with MC1R agonists. The role of nuclear factor erythroid 2-related factor 2 (Nrf2) in MC1R-mediated protection against αSyn was characterized in vitro. Furthermore, MC1R expression was determined in human postmortem midbrain from patients with PD and unaffected subjects.. Targeted expression of αSyn in the nigrostriatal pathway induced exacerbated synuclein pathologies in MC1R mutant mice, which were accompanied by neuroinflammation and altered Nrf2 responses, and reversed by the human MC1R transgene. Two MC1R agonists were neuroprotective against αSyn-induced dopaminergic neurotoxicity. In vitro experiments showed that Nrf2 was a necessary mediator of MC1R effects. Lastly, MC1R was present in dopaminergic neurons in the human substantia nigra and appeared to be reduced at the tissue level in PD patients.. Our study supports an interaction between MC1R and αSyn that can be mediated by neuronal MC1R possibly through Nrf2. It provides evidence for MC1R as a therapeutic target and a rationale for development of MC1R-activating strategies for PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Parkinson Disease; Receptor, Melanocortin, Type 1

The etiology of Parkinson's disease is poorly understood and is most commonly associated with advancing age, genetic predisposition, or environmental toxins. Epidemiological findings suggest that patients have a higher risk of developing Parkinson's disease after ischemic stroke, but this potential causality lacks mechanistic evidence. We investigated the long-term effects of ischemic stroke on pathogenesis in hemizygous TgM83 mice, which express human α-synuclein with the familial A53T mutation without developing any neuropathology or signs of neurologic disease for more than 600 days. We induced transient focal ischemia by middle cerebral artery occlusion in 2-month-old TgM83

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Infarction, Middle Cerebral Artery; Inflammation; Ischemic Stroke; Mice; Mice, Transgenic; Parkinson Disease

Anxiety and depression affect 35-50% of patients with Parkinson's disease (PD), often precede the onset of motor symptoms, and have a negative impact on their quality of life. Dysfunction of the serotonergic (5-HT) system, which regulates mood and emotional pathways, occurs during the premotor phase of PD and contributes to a variety of non-motor symptoms. Furthermore, α-synuclein (α-Syn) aggregates were identified in raphe nuclei in the early stages of the disease. However, there are very few animal models of PD-related neuropsychiatric disorders. Here, we develop a new mouse model of α-synucleinopathy in the 5-HT system that mimics prominent histopathological and neuropsychiatric features of human PD. We showed that adeno-associated virus (AAV5)-induced overexpression of wild-type human α-Syn (h-α-Syn) in raphe 5-HT neurons triggers progressive accumulation, phosphorylation, and aggregation of h-α-Syn protein in the 5-HT system. Specifically, AAV5-injected mice displayed axonal impairment in the output brain regions of raphe neurons, and deficits in brain-derived neurotrophic factor (BDNF) expression and 5-HT neurotransmission, resulting in a depressive-like phenotype. Intracerebroventricular treatment with an indatraline-conjugated antisense oligonucleotide (IND-ASO) for four weeks induced an effective and safe reduction of h-α-Syn synthesis in 5-HT neurons and its accumulation in the forebrain, alleviating early deficits of 5-HT function and improving the behavioural phenotype. Altogether, our findings show that α-synucleinopathy in 5-HT neurons negatively affects brain circuits that control mood and emotions, resembling the expression of neuropsychiatric symptoms occurring at the onset of PD. Early preservation of 5-HT function by reducing α-Syn synthesis/accumulation may alleviate PD-related depressive symptoms.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Neurons; Oligonucleotides; Phenotype; Prosencephalon; Quality of Life; Serotonin

Parkinson's disease (PD) is clinically defined by the presence of the cardinal motor symptoms, which are associated with a loss of dopaminergic nigrostriatal neurons in the substantia nigra pars compacta (SNpc). While SNpc neurons serve as the prototypical cell-type to study cellular vulnerability in PD, there is an unmet need to extent our efforts to other neurons at risk. The noradrenergic locus coeruleus (LC) represents one of the first brain structures affected in Parkinson's disease (PD) and plays not only a crucial role for the evolving non-motor symptomatology, but it is also believed to contribute to disease progression by efferent noradrenergic deficiency. Therefore, we sought to characterize the electrophysiological properties of LC neurons in two distinct PD models: (1) in an in vivo mouse model of focal α-synuclein overexpression; and (2) in an in vitro rotenone-induced PD model. Despite the fundamental differences of these two PD models, α-synuclein overexpression as well as rotenone exposure led to an accelerated autonomous pacemaker frequency of LC neurons, accompanied by severe alterations of the afterhyperpolarization amplitude. On the mechanistic side, we suggest that Ca

Topics: alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Locus Coeruleus; Male; Mice; Mice, Inbred C57BL; Neurons; Norepinephrine; Parkinson Disease; Pars Compacta; Prodromal Symptoms; Rotenone; Small-Conductance Calcium-Activated Potassium Channels

α-Synuclein accumulation is implicated in the pathogenesis of neurodegenerative diseases, including Parkinson's disease (PD). Previously, we reported that Fas-associated factor 1 (FAF1), which plays a role in PD pathogenesis, potentiates α-synuclein accumulation through autophagy impairment in dopaminergic neurons. In this study, we show that KM-819, a FAF1-targeting compound, which has completed phase I clinical trials, interferes with α-synuclein accumulation in the mouse brain, as well as in human neuronal cells (SH-SY5Ys). KM-819 suppressed the accumulation of monomeric, oligomeric, and aggregated forms of α-synuclein in neuronal cells. Furthermore, KM-819 restored the turnover rate of α-synuclein in FAF1-overexpressing SH-SY5Y cells, implicating KM-819-mediated reconstitution of the α-synuclein degradative pathway. In addition, KM-819 reconstituted autophagic flux in FAF1-transfected SH-SY5Y cells, also suppressing α-synuclein-induced mitochondrial dysfunction. Moreover, oral administration of KM-819 also interfered with α-synuclein accumulation in the midbrain of mice overexpressing FAF1 via an adeno-associated virus system. Consistently, KM-819 reduced α-synuclein accumulation in both the hippocampus and the midbrain of human A53T α-synuclein transgenic mice. Collectively, these data imply that KM-819 may have therapeutic potential for patients with PD.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Animals; Apoptosis Regulatory Proteins; Autophagy; Brain; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Transgenic; Parkinson Disease

Mutations in PTEN-induced putative kinase 1 (PINK1) cause autosomal recessive Parkinson's disease (PD) and contribute to the risk of sporadic PD. However, the relationship between PD-related PINK1 mutations and alpha-synuclein (α-syn) aggregation-a main pathological component of PD-remains unexplored.. To investigate whether α-syn pathology is exacerbated in the absence of PINK1 after α-syn preformed fibril (PFF) injection in a PD mouse model and its effects on neurodegeneration.. In this study, 10-week-old Pink1 knockout (KO) and wildtype (WT) mice received stereotaxic unilateral striatal injection of recombinant mouse α-syn PFF. Then, α-syn pathology progression, inflammatory responses, and neurodegeneration were analyzed via immunohistochemistry, western blot analysis, and behavioral testing.. After PFF injection, the total α-syn levels significantly increased, and pathological α-syn was markedly aggregated in Pink1 KO mice compared with Pink1 WT mice. Then, earlier and more severe neuronal loss and motor deficits occurred. Moreover, compared with WT mice, Pink1 KO mice had evident microglial/astrocytic immunoreactivity and prolonged astrocytic activation, and a higher rate of protein phosphatase 2A phosphorylation, which might explain the greater α-syn aggravation and neuronal death.. The loss of Pink1 function accelerated α-syn aggregation, accumulation and glial activation, thereby leading to early and significant neurodegeneration and behavioral impairment in the PD mouse model. Therefore, our findings support the notion that PINK1 dysfunction increases the risk of synucleinopathy.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Knockout; Parkinson Disease; Protein Kinases; PTEN Phosphohydrolase; Substantia Nigra; Synucleinopathies

Parkinson's disease (PD) is the second most common neurodegenerative disease without cure or effective treatment. This study explores whether the yeast internal NADH-quinone oxidoreductase (NDI1) can functionally replace the defective mammalian mitochondrial complex I, which may provide a gene therapy strategy for treating sporadic PD caused by mitochondrial complex I dysfunction.. Recombinant lentivirus expressing NDI1 was transduced into SH-SY5Y cells, or recombinant adeno-associated virus type 5 expressing NDI1 was transduced into the right substantia nigra pars compacta (SNpc) of mouse. PD cell and mouse models were established by rotenone treatment. The therapeutic effects of NDI1 on rotenone-induced PD models in vitro and vivo were assessed in neurobehavior, neuropathology, and mitochondrial functions, by using the apomorphine-induced rotation test, immunohistochemistry, immunofluorescence, western blot, complex I enzyme activity determination, oxygen consumption detection, ATP content determination and ROS measurement.. NDI1 was expressed and localized in mitochondria in SH-SY5Y cells. NDI1 resisted rotenone-induced changes in cell morphology, loss of cell viability, accumulation of α-synuclein and pS129 α-synuclein, mitochondrial ROS production and mitochondria-mediated apoptosis. The basal and maximal oxygen consumption, mitochondrial coupling efficiency, basal and oligomycin-sensitive ATP and complex I activity in cell model were significantly increased in rotenone + NDI1 group compared to rotenone + vector group. NDI1 was efficiently expressed in dopaminergic neurons in the right SNpc without obvious adverse effects. The rotation number to the right side (NDI1-treated side) was significantly increased compared to that to the left side (untreated side) in mouse model. The number of viable dopaminergic neurons, the expression of tyrosine hydroxylase, total and maximal oxygen consumption, mitochondrial coupling efficiency and complex I enzyme activity in right substantia nigra, and the content of dopamine in right striatum were significantly increased in rotenone + NDI1 group compared to rotenone + vector group.. Yeast NDI1 can rescue the defect of oxidative phosphorylation in rotenone-induced PD cell and mouse models, and ameliorate neurobehavioral and neuropathological damages. The results may provide a basis for the yeast NDI1 gene therapy of sporadic PD caused by mitochondrial complex I dysfunction.

Topics: Adenosine Triphosphate; alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Electron Transport Complex I; Genetic Therapy; Mammals; Mice; Neurodegenerative Diseases; Parkinson Disease; Reactive Oxygen Species; Rotenone; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins

Growing evidence suggests an association between Parkinson's disease (PD) and diabetes mellitus (DM). At the cellular level, long-term elevated levels of glucose have been shown to lead to nigrostriatal degeneration in PD models. However, the underlying mechanism is still unclear. Previously, we have elucidated the potential of type 2 diabetes mellitus (T2DM) in facilitating PD progression, involving aggregation of both alpha-synuclein (α-syn) and islet amyloid polypeptide in the pancreatic and brain tissues. However, due to the complicated effect of insulin resistance on PD onset, the actual mechanism of hyperglycemia-induced dopaminergic degeneration remains unknown.. We employed the type 1 diabetes mellitus (T1DM) model induced by streptozotocin (STZ) injection in a transgenic mouse line (BAC-α-syn-GFP) overexpressing human α-syn, to investigate the direct effect of elevated blood glucose on nigrostriatal degeneration.. STZ treatment induced more severe pathological alterations in the pancreatic islets and T1DM symptoms in α-syn-overexpressing mice than in wild-type mice, at one month and three months after STZ injections. Behavioral tests evaluating motor performance confirmed the nigrostriatal degeneration. Furthermore, there was a marked decrease in dopaminergic profiles and an increase of α-syn accumulation and Serine 129 (S129) phosphorylation in STZ-treated α-syn mice compared with the vehicle-treated mice. In addition, more severe neuroinflammation was observed in the brains of the STZ-treated α-syn mice.. Our results solidify the potential link between DM and PD, providing insights into how hyperglycemia induces nigrostriatal degeneration and contributes to pathogenic mechanisms in PD.

Topics: alpha-Synuclein; Animals; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Disease Models, Animal; Dopamine; Hyperglycemia; Mice; Mice, Transgenic; Parkinson Disease

Evodileptin B (1) is a natural anthranilate derivative isolated from the ethanol extract of the aerial parts of Evodia lepta (Spreng.) Merr., a traditional medicinal plant of the family Rutaceae. We readily synthesized 1 via the amidation of phloretic with methyl anthranilate and evaluate its neuroprotective activity using a C. elegans Parkinson's disease (PD) model. The results showed that evodilpetin B ameliorated MPP

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Disease Models, Animal; Evodia; Neuroprotective Agents; ortho-Aminobenzoates; Parkinson Disease; Rutaceae

Dopaminergic neuron degeneration in the midbrain plays a pivotal role in motor symptoms associated with Parkinson's disease. However, non-motor symptoms of Parkinson's disease and post-mortem histopathology confirm dysfunction in other brain areas, including the locus coeruleus and its associated neurotransmitter norepinephrine. Here, we investigate the role of central norepinephrine-producing neurons in Parkinson's disease by chronically stimulating catecholaminergic neurons in the locus coeruleus using chemogenetic manipulation. We show that norepinephrine neurons send complex axonal projections to the dopaminergic neurons in the substantia nigra, confirming physical communication between these regions. Furthermore, we demonstrate that increased activity of norepinephrine neurons is protective against dopaminergic neuronal depletion in human α-syn A53T missense mutation over-expressing mice and prevents motor dysfunction in these mice. Remarkably, elevated norepinephrine neurons action fails to alleviate α-synuclein aggregation and microgliosis in the substantia nigra suggesting the presence of an alternate neuroprotective mechanism. The beneficial effects of high norepinephrine neuron activity might be attributed to the action of norepinephrine on dopaminergic neurons, as recombinant norepinephrine treatment increased primary dopaminergic neuron cultures survival and neurite sprouting. Collectively, our results suggest a neuroprotective mechanism where noradrenergic neurons activity preserves the integrity of dopaminergic neurons, which prevents synucleinopathy-dependent loss of these cells.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Locus Coeruleus; Mice; Mice, Transgenic; Norepinephrine; Parkinson Disease; Substantia Nigra; Synucleinopathies

Preclinical rodent models of Parkinson's aim to recapitulate some of the hallmarks of the disease as it presents in humans, including the progressive neuronal loss of dopaminergic neurons in the midbrain as well as the development of a behavioral phenotype. AAV vector-based models of alpha-synuclein overexpression are a promising tool to achieve such animal models with high face and predictive validity.. We have developed a preclinical rodent model of Parkinson's disease using an AAV-vector based overexpression of human alpha-synuclein. In the present work we characterize this model on a behavioral and histopathological level.. We use a AAV9 vector for transgene delivery to overexpress human alpha-synuclein under a CBA promoter. We compare the behavioral and histopathological changes to a AAV vector control group where the transgene was omitted and to that of a 6-OHDA lesion control. We assessed the behavioral performance of these three groups on a series of tests (Cylinder, Stepping, Corridor) at baseline and up to 22 weeks post-injection at which point we performed electrochemical recordings of dopamine kinetics.. The overexpression of human alpha-synuclein led to the progressive manifestation of behavioral deficits on all three behavioral tests. This was accompanied with impaired dopamine release and reuptake kinetics as demonstrated by electrochemical detection methods. Histopathological quantifications corroborated the findings that we induced a moderate cell loss with remaining cells displaying pathological markers which are abundant in the brains of human PD patients.. In the present work we developed a characterized a rat model of PD that closely mimics human disease development and pathology. Such model will be of great use for investigation of disease mechanisms and early therapeutic interventions.

Topics: alpha-Synuclein; Animals; Behavior Rating Scale; Dependovirus; Disease Models, Animal; Dopamine; Genetic Vectors; Humans; Mesencephalon; Rats; Rats, Sprague-Dawley; Substantia Nigra

Parkinson's disease (PD) is a multifactorial ailment that severely affects the viability of dopaminergic neurons leading to progressive loss of motor control. The current regimen for PD treatment includes synthetic drugs that lack efficacy and cause serious side effects. Consequently, recent drug development studies are focusing on alternative medicines from plant sources. Artemisia pallens Wall. ex DC, commonly known as davana, is an annual aromatic herb cultivated in southern India. Given the diverse traditional and scientifically documented therapeutic effects of A. pallens, the pharmacological potential of the isolates of the plant, namely bicyclogermacrene (D1), cis-davanone (D3), and cis-hydroxy davanone (D5), was tested for anti-Parkinson's activity in Caenorhabditis elegans model. The tested compounds alleviated α-synuclein (α-syn) aggregation and maximum decline was observed in 25 μM D1 supplemented worms. Additionally, D1 modulated dopamine regulated nonanol-1 repulsion and locomotory behaviour of C. elegans validating its future use as a dopamine-enhancing agent. The genetic regulation mediating the above effects validated through the qPCR study showed that D1 supplementation displayed its anti-Parkinson's effect through upregulation of the antioxidant defence system genes (superoxide dismutase (sod)-1, sod-2, and sod-4) and PD associated pdr-1 gene that maintains the mitochondrial proteostasis. The molecular docking studies of C. elegans PDR-1 with D1 further confirmed its contribution in D1 induced abridgment of Parkinson disease linked pathologies in C. elegans disease model. Hence, this article proposes D1 as an effective regimen for curtailing the Parkinson disease linked pathologies through mechanism of maintaining cellular redox state and proteostasis.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Artemisia; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Molecular Docking Simulation; Parkinson Disease; Parkinsonian Disorders; Sesquiterpenes; Superoxide Dismutase

Heterozygous mutations in the GBA1 gene - encoding lysosomal glucocerebrosidase (GCase) - are the most common genetic risk factors for Parkinson's disease (PD). Experimental evidence suggests a correlation between decreased GCase activity and accumulation of alpha-synuclein (aSyn). To enable a better understanding of the relationship between aSyn and GCase activity, we developed and characterized two mouse models that investigate aSyn pathology in the context of reduced GCase activity. The first model used constitutive overexpression of wild-type human aSyn in the context of the homozygous GCase activity-reducing D409V mutant form of GBA1. Although increased aSyn pathology and grip strength reductions were observed in this model, the nigrostriatal system remained largely intact. The second model involved injection of aSyn preformed fibrils (PFFs) into the striatum of the homozygous GBA1 D409V knock-in mouse model. The GBA1 D409V mutation did not exacerbate the pathology induced by aSyn PFF injection. This study sheds light on the relationship between aSyn and GCase in mouse models, highlighting the impact of model design on the ability to model a relationship between these proteins in PD-related pathology.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Mutation; Parkinson Disease

Topics: alpha-Synuclein; Animals; Disease Models, Animal; DNA Damage; Neuroinflammatory Diseases; Parkinson Disease

Among the pathological events associated with the dopaminergic neurodegeneration characteristic of Parkinson's disease (PD) are the accumulation of toxic forms of α-synuclein and microglial activation associated with neuroinflammation. Although numerous other processes may participate in the pathogenesis of PD, the two factors mentioned above may play critical roles in the initiation and progression of dopamine neuron degeneration in PD. In this study, we employed a slowly progressing model of PD using adeno-associated virus-mediated expression of human A53T α-synuclein into the substantia nigra on one side of the brain and examined the microglial response in the striatum on the injected side compared to the non-injected (control) side. We further examined the extent to which administration of the neuroprotective ganglioside GM1 influenced α-synuclein-induced glial responses. Changes in a number of microglial morphological measures (i.e., process length, number of endpoints, fractal dimension, lacunarity, density, and cell perimeter) were indicative of the presence of activated microglial and an inflammatory response on the injected side of the brain, compared to the control side. In GM1-treated animals, no significant differences in microglial morphology were observed between the injected and control striata. Follow-up studies showed that mRNA expression for several inflammation-related genes was increased on the A53T α-synuclein injected side vs. the non-injected side in saline-treated animals and that such changes were not observed in GM1-treated animals. These data show that inhibition of microglial activation and potentially damaging neuroinflammation by GM1 ganglioside administration may be among the many factors that contribute to the neuroprotective effects of GM1 in this model and possibly in human PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; G(M1) Ganglioside; Inflammation; Microglia; Parkinson Disease; Rats; Substantia Nigra

Parkinson's disease (PD) is a progressive neurodegenerative motor disorder without an available therapeutic to halt the formation of Lewy bodies for preventing dopaminergic neuronal loss in the nigrostriatal pathway. Since oxidative-stress-mediated damage has been commonly reported as one of the main pathological mechanisms in PD, we assessed the efficacy of a novel NOX inhibitor from AptaBio Therapeutics (C-6) in dopaminergic cells and PD mouse models. The compound reduced the cytotoxicity and enhanced the cell viability at various concentrations against MPP+ and α-synuclein preformed fibrils (PFFs). Further, the levels of ROS and protein aggregation were significantly reduced at the optimal concentration (1 µM). Using two different mouse models, we gavaged C-6 at two different doses to the PD sign-displaying transgenic mice for 2 weeks and stereotaxically PFF-injected mice for 5 weeks. Our results demonstrated that both C-6-treated mouse models showed alleviated motor deficits in pole test, hindlimb clasping, crossbeam, rotarod, grooming, and nesting analyses. We also confirmed that the compound treatment reduced the levels of protein aggregation, along with phosphorylated-α-synuclein, in the striatum and ventral midbrain and further dopaminergic neuronal loss. Taken together, our results strongly suggest that NOX inhibition can be a potential therapeutic target for PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Mice; Mice, Transgenic; Nerve Degeneration; Parkinson Disease; Protein Aggregates

Dementia with Lewy bodies (DLB) is the second most common type of neurodegenerative dementia after Alzheimer's disease (AD). Neuroinflammation plays an important role in neurodegenerative diseases. It is urgent to unravel the pathogenesis of DLB and find potential therapeutic drugs. Here, we investigated the pharmacological effects of the NLRP3 inflammasome inhibitor MCC950 in A53T α-synuclein transgenic line M83 mice aged 4 months. The behavioral tests including Y-maze, Barnes maze, nest building and Rotarod showed that MCC950 significantly improved the cognitive dysfunction symptom without affecting the motor coordination after consecutive intragastric administration every day for 5 weeks. Furthermore, immunostaining or immunoblotting experiments on the hippocampal tissue were performed, and the results suggested that MCC950 not only inhibited the expression of NLRP3, and suppressed the activation of astrocytes and microglia, but also promoted the mTOR-mediated autophagy pathway to reduce human α-synuclein accumulation. Our findings further demonstrate that line M83 mice may be used as an animal model for DLB research, and can provide preclinical evidences for the development of MCC950 as a promising therapeutic drug.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Disease Models, Animal; Furans; Hippocampus; Indenes; Lewy Body Disease; Mice; Mice, Transgenic; NLR Family, Pyrin Domain-Containing 3 Protein; Sulfonamides

Parkinson's disease involves aberrant aggregation of the synaptic protein alpha-synuclein (aSyn) in the nigrostriatal tract. We have previously shown that proSAAS, a small neuronal chaperone, blocks aSyn-induced dopaminergic cytotoxicity in primary nigral cultures.. To determine if proSAAS overexpression is neuroprotective in animal models of Parkinson's disease.. proSAAS- or GFP-encoding lentivirus was injected together with human aSyn-expressing AAV unilaterally into the substantia nigra of rats and motor asymmetry assessed using a battery of motor performance tests. Dopamine neuron survival was assessed by nigral stereology and striatal tyrosine hydroxylase (TH) densitometry. To examine transsynaptic spread of aSyn, aSyn AAV was injected into the vagus of mice in the presence of AAVs encoding either GFP or proSAAS; the spread of aSyn-positive neurites into rostral nuclei was quantified following immunohistochemistry.. Coinjection of proSAAS-encoding lentivirus profoundly reduced the motor asymmetry caused by unilateral nigral AAV-mediated human aSyn overexpression. This was accompanied by significant amelioration of the human aSyn-induced loss of both nigral TH-positive cells and striatal TH-positive terminals, demonstrating clear proSAAS-mediated protection of the nigrostriatal tract. ProSAAS overexpression reduced human aSyn protein levels in nigra and striatum and reduced the loss of TH protein in both regions. Following vagal administration of human aSyn-encoding AAV, the number of human aSyn-positive neurites in the pons and caudal midbrain was considerably reduced in mice coinjected with proSAAS-, but not GFP-encoding AAV, supporting proSAAS-mediated blockade of transsynaptic aSyn transmission.. The proSAAS chaperone may represent a promising target for therapeutic development in Parkinson's disease.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Mice; Neuroprotection; Parkinson Disease; Rats; Rodentia; Substantia Nigra; Tyrosine 3-Monooxygenase

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Chitosan; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinson Disease; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt

Parkinson's disease (PD) is the second most common neurodegenerative disease, and no treatment is available to stop its progression. Studies have shown that the colonic pathology of PD precedes that of the brain. The 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model and the human A53T α-synuclein (α-syn) transgenic PD mouse model show colonic pathology and intestinal dopaminergic neuronal damage, which is comparable to the intestinal pathology of PD. Cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1), which are brain-gut peptides, have neurotrophic and anti-inflammatory properties. Two GLP-1R agonists have already shown robust effects in phase II trials in PD patients. However, whether they have beneficial effects on colonic pathology in PD remains unclear. In this study, MPTP-treated mice and human A53T α-syn transgenic mice were intraperitoneally injected with a CCK analogue or Liraglutide, a GLP-1 analogue, once a day for 5 weeks. Levels of colonic epithelial tight junction proteins including occludin and zonula occludens-1 (ZO-1), inflammatory biomarkers including inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α), brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH) and α-syn were analyzed. The results show that the CCK analogue and Liraglutide both restored the disruption of intestinal tight junction, reduced colonic inflammation, inhibited colonic dopaminergic neurons reduction and the accumulation of α-syn oligomers in the colon of both PD mice models. This study suggested that CCK or GLP-1 analogues could be beneficial to the improvement of leaky gut barrier, inflammation, dopaminergic neuron impairment and accumulation of α-syn in the colon of PD patients.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Cholecystokinin; Colon; Disease Models, Animal; Dopaminergic Neurons; Glucagon-Like Peptide 1; Humans; Inflammation; Liraglutide; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease; Tight Junctions

Potentially druggable mechanisms underlying synaptic deficits seen in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are under intense interrogations. In addition to defective synaptic vesicle trafficking, cytoskeletal disruption, autophagic perturbation, and neuroinflammation, hyperphosphorylation of microtubule-associated protein collapsin response mediator protein 2 (CRMP2, also known as DPYSL2) is newly determined to correlate with synaptic deficits in human DLB. The small molecule experimental therapeutic, lanthionine ketimine-5-ethyl ester (LKE), appears to interact with CRMP2 in a host of neurodegenerative mouse models, normalizing its phosphorylation level while promoting healthful autophagy in cell culture models and suppressing the proinflammatory phenotype of activated microglia. Accordingly, this study examined the effect of LKE on α-synuclein A53T transgenic (Tg) mice which were employed as a DLB model. We found that chronic administration of LKE to A53T mice suppressed (1) the accumulation of LBs, (2) neuroinflammatory activation of microglia, (3) impairment of contextual fear memory, and (4) CRMP2 phosphorylation at Thr509 in A53T Tg mice. These results suggest that CRMP2 phosphorylation by GSK3β in the hippocampus is related to pathology and memory impairment in DLB, and LKE may have clinical implications in the treatment of α-synucleinopathy.

Topics: alpha-Synuclein; Amino Acids, Sulfur; Animals; Disease Models, Animal; Esters; Humans; Mice; Mice, Transgenic; Synucleinopathies

Parkinson's disease is a neurodegenerative disorder that causes motor and nonmotor symptoms due to the loss of dopaminergic nerves and is characterized by the presence of Lewy bodies, which are mainly composed of α-synuclein. Glucosylceramidase beta (GBA), which is a causative gene of autosomal recessive Gaucher disease, is also known to be a risk gene for Parkinson's disease. In this study, we tried to detect synergistic effects of α-synuclein accumulation and gba depletion on dopaminergic neurodegeneration in zebrafish.. We generated a transgenic line of zebrafish overexpressing the A53T α-synuclein and gba mutant fish, and analyzed pathologies of α-synuclein aggregation and neurodegeneration.. Zebrafish overexpressing the A53T α-synuclein did not exhibit α-synuclein aggregate formation. After the loss of gba function in this mutant α-synuclein transgenic line, we observed the marked presence of α-synuclein aggregates. Loss of gba function in zebrafish resulted in dopaminergic and noradrenergic neurodegeneration but this level of neurodegeneration was not exacerbated by overexpression of mutant α-synuclein.. These results indicate that loss of gba function was sufficient to generate a neurodegenerative phenotype in zebrafish regardless of the expression of α-synuclein.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Mutation; Neurodegenerative Diseases; Parkinson Disease; Zebrafish

The α-synuclein released by neurons activates microglia, which then engulfs α-synuclein for degradation via autophagy. Reactive microglia are a major pathological feature of Parkinson's disease (PD), although the exact role of microglia in the pathogenesis of PD remains unclear. Transient receptor potential vanilloid type 1 (TRPV1) channels are nonselective cation channel protein that have been proposed as neuroprotective targets in neurodegenerative diseases.. Using metabolic profiling, microglia energy metabolism was measured including oxidative phosphorylation and aerobic glycolysis. The mRFP-GFP-tagged LC3 reporter was introduced to characterize the role of TRPV1 in microglial autophagy. α-synuclein preformed fibril (PFF) TRPV1. We found that acute exposure to PFF caused microglial activation as a result of metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis via the AKT-mTOR-HIF-1α pathway. Activated microglia eventually reached a state of chronic PFF-tolerance, accompanied by broad defects in energy metabolism. We showed that metabolic boosting by treatment with the TRPV1 agonist capsaicin rescued metabolic impairments in PFF-tolerant microglia and also defects in mitophagy caused by disruption of the AKT-mTOR-HIF-1α pathway. Capsaicin attenuated phosphorylation of α-synuclein in primary neurons by boosting phagocytosis in PFF-tolerant microglia in vitro. Finally, we found that behavioral deficits and loss of dopaminergic neurons were accelerated in the PFF TRPV1. The findings suggest that modulating microglial metabolism might be a new therapeutic strategy for PD.

Topics: alpha-Synuclein; Animals; Capsaicin; Disease Models, Animal; Dopaminergic Neurons; Mice; Microglia; Parkinson Disease; Proto-Oncogene Proteins c-akt; TOR Serine-Threonine Kinases; TRPV Cation Channels

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra (SN), reducing dopaminergic levels in the striatum and affecting motor control. Herein, we investigated the potential relationship between integrin α7 (

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antigens, CD; Disease Models, Animal; Integrin alpha Chains; Integrins; Mice; Muscles; Parkinson Disease; RNA, Small Interfering; Tyrosine 3-Monooxygenase

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Fruit and Vegetable Juices; Neuroprotective Agents; Parkinson Disease; Rats; Rats, Wistar; Rotenone; Vaccinium macrocarpon

Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HTT gene for which no therapies are available. HTT mutation causes protein misfolding and aggregation, preferentially affecting medium spiny neurons (MSNs) of the basal ganglia. Transcriptional perturbations in synaptic genes and neuroinflammation are key processes that precede MSN dysfunction and motor symptom onset. Understanding the interplay between these processes is crucial to develop effective therapeutic strategies to treat HD. We investigated the role of protein kinase CK2α', a kinase upregulated in MSNs in HD and previously associated with Parkinson's disease (PD), in the regulation of neuroinflammation and synaptic function in HD. We used the heterozygous knock-in zQ175 HD mouse model and compared that to zQ175 mice lacking one allele of CK2α' (zQ175:CK2α'

Topics: alpha-Synuclein; Animals; Casein Kinase II; Corpus Striatum; Disease Models, Animal; Humans; Huntington Disease; Mice; Neurons

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are characterized by the aberrant accumulation of intracytoplasmic misfolded and aggregated α-synuclein (α-Syn), resulting in neurodegeneration associated with inflammation. The propagation of α-Syn aggregates from cell to cell is implicated in the spreading of pathological α-Syn in the brain and disease progression. We and others demonstrated that antibodies generated after active and passive vaccinations could inhibit the propagation of pathological α-Syn in the extracellular space and prevent/inhibit disease/s in the relevant animal models. We recently tested the immunogenicity and efficacy of four DNA vaccines on the basis of the universal MultiTEP platform technology in the DLB/PD mouse model. The antibodies generated by these vaccines efficiently reduced/inhibited the accumulation of pathological α-Syn in the different brain regions and improved the motor deficit of immunized female mice. The most immunogenic and preclinically effective vaccine, PV-1950D, targeting three B-cell epitopes of pathological α-Syn simultaneously, has been selected for future IND-enabling studies. However, to ensure therapeutically potent concentrations of α-Syn antibodies in the periphery of the vaccinated elderly, we developed a recombinant protein-based MultiTEP vaccine, PV-1950R/A, and tested its immunogenicity in young and aged D-line mice. Antibody responses induced by immunizations with the PV-1950R/A vaccine and its homologous DNA counterpart, PV-1950D, in a mouse model of PD/DLB have been compared.

Topics: alpha-Synuclein; Animals; Antibodies; Disease Models, Animal; Epitopes, B-Lymphocyte; Female; Lewy Body Disease; Mice; Parkinson Disease; Recombinant Proteins; Vaccines, DNA

The major hallmark of Parkinson's disease (PD) is the degeneration of dopaminergic neurons in the substantia nigra (SN), which is responsible for the core motor symptoms of PD. Currently, there is no cure for PD, and its prevalence is increasing, prompting the search for novel neuroprotective treatments. Neuroinflammation is a core pathological process in PD, evident by increased inflammatory biomarkers in the SN and cerebrospinal fluid. Interestingly, epidemiological studies have reported a reduced risk of PD in users of non-steroidal anti-inflammatory drugs compared to non-users, suggesting the neuroprotective potential of anti-inflammatory drugs. Therefore, this study aimed to: (1) test the efficacy of novel oral formulations of edaravone (EDR) and curcumin (CUR) (which possess anti-inflammatory and anti-oxidative properties) to alleviate motor and non-motor symptoms, and associated pathology in the intrastriatal lipopolysaccharide (LPS) model of PD; (2) investigate the expression of proteins linked to familial PD and markers of autophagy in the intrastriatal LPS model treated with EDR and CUR. Fifty-two C57BL/6 mice were divided into 4 groups, namely; (1) control + vehicle; (2) LPS + vehicle; (3) LPS + EDR (made in vehicle) and (4) LPS + CUR (made in vehicle). 10 μg of LPS was administered stereotaxically into the right striatum, and EDR and CUR treatments were initiated 2-weeks after the LPS injections. Behavioural tests were carried out at 4- and 8-weeks after LPS injection followed by tissue collection at 8-weeks. Intrastriatal administration of LPS induced motor deficits and anxiety-like behaviours at 4- and 8-weeks, which were accompanied by astroglial activation, increased protein expression of α-synuclein, heat shock cognate protein of 70 kDa (HSC-70) and Rab-10, and reduced levels of tyrosine hydroxylase (TH) protein in the striatum. Additionally, LPS induced astroglial activation in the olfactory bulb, along with changes in the protein expression of HSC-70. The changes associated with EDR and CUR in the striatum and olfactory bulb were not statistically significant compared to the LPS group. Intrastriatal administration of LPS induced pathological changes of PD such as motor deficits, reduced expression of TH protein and increased α-synuclein protein, as well as some alterations in proteins linked to familial PD and autophagy in the olfactory bulb and striatum, without pronounced therapeutic effects of EDR and CUR. Our results may suggest tha

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Curcumin; Disease Models, Animal; Edaravone; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Parkinson Disease

Degeneration of the nigrostriatal tract is a neuropathological hallmark of Parkinson's disease (PD). A differential intraneuronal vulnerability of dopaminergic neurons within the substantia nigra (SN) has been suggested, starting as an axonopathy followed by neuronal cell loss that is accompanied with motor deficits. To date, there is no therapy available to delay or halt this neurodegeneration. Nuclear factor (erythroid-derived 2)-like-2 factor (Nrf2) and histone deacetylase 1 (HDAC1) are crucial molecular regulators that undergo nucleo-cytoplasmic shuttling and are involved in regulation of axonal and perikarya degeneration of neurons under various pathologic conditions. We here aimed to analyze the time course of dopaminergic neurodegeneration in an AAV PD rat model overexpressing human mutated A53T α-synuclein (haSyn), differentially correlate striatal terminal and SN perikarya loss with behavioral deficits and investigate if nucleo-cytoplasmic Nrf2 and HDAC1 expression are altered in dopaminergic perikarya of the haSyn PD rat model. We observed impaired motor performance in haSyn PD rats assessed by the single pellet reaching task at four- and six-weeks post AAV injection (P < 0.05 each). However, only striatal terminal loss correlated significantly with motor deficits in haSyn PD rats, indicating that parkinsonian motor features reflect the striatal dopaminergic denervation, but cannot be taken as an indirect measure of neurodegeneration per se. Immunofluorescence staining demonstrated an upregulation of HDAC1 in the dopaminergic cell nucleus (P < 0.05) while no changes were observed for Nrf2. These data suggest a critical functional role of the axonopathy on motor behavior in haSyn PD rats and mechanistically point towards an impaired nucleo-cytoplasmic translocation of HDAC1 and thus a potential role of disturbed histone acetylation in neurodegeneration.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; NF-E2-Related Factor 2; Parkinson Disease; Rats; Substantia Nigra

Parkinson's disease (PD) is identified by the loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc), and is correlated to aggregates of proteins such as α-synuclein, Lewy's bodies. Although the PD etiology remains poorly understood, evidence suggests a main role of oxidative stress on this process. Lippia grata Schauer, known as "alecrim-do-mato", "alecrim-de-vaqueiro", "alecrim-da-chapada", is a native bush from tropical areas mainly distributed throughout the Central and South America. This plant species is commonly used in traditional medicine for relief of pain and inflammation conditions, and that has proven antioxidant effects. We evaluated the effects of essential oil of the L. grata after its complexed with β-cyclodextrin (LIP) on PD animal model induced by reserpine (RES). Behavioral assessments were performed across the treatment. Upon completion the treatment, the animals were euthanized, afterwards their brains were isolated and processed for immunohistochemical and oxidative stress analysis. The LIP treatment delayed the onset of the behavior of catalepsy, decreased the number of oral movements and prevented the memory impairment on the novel object recognition task. In addition, the treatment with LIP protected against dopaminergic depletion in the SNpc and dorsal striatum (STRd), and decreased the α-syn immunoreactivity in the SNpc and hippocampus (HIP). Moreover, there was reduction of the oxidative stability index. These findings demonstrated that the LIP treatment has neuroprotective effect in a progressive parkinsonism model, suggesting that LIP could be an important source for novel treatment approaches in PD.

Topics: alpha-Synuclein; Animals; Antioxidants; beta-Cyclodextrins; Disease Models, Animal; Dopaminergic Neurons; Lippia; Neuroprotective Agents; Oils, Volatile; Parkinson Disease; Parkinsonian Disorders; Reserpine; Substantia Nigra

This study underlines the importance of treadmill exercise in reducing α-synuclein (α-syn) spreading in the A53T brain and protecting nigral dopaminergic neurons. Preformed α-syn fibril (PFF) seeding in the internal capsule of young A53T α-syn mice leads to increased spreading of α-syn to substantia nigra and motor cortex and concomitant loss of nigral dopaminergic neurons. However, regular treadmill exercise decreases α-syn spreading in the brain and protects nigral dopaminergic neurons in PFF-seeded mice. Accordingly, treadmill exercise also mitigates α-synucleinopathy in aged A53T mice. While investigating this mechanism, we have observed that treadmill exercise induces the activation of peroxisome proliferator-activated receptor α (PPARα) in the brain to stimulate lysosomal biogenesis via TFEB. Accordingly, treadmill exercise remains unable to stimulate TFEB and reduce α-synucleinopathy in A53T mice lacking PPARα, and fenofibrate, a prototype PPARα agonist, reduces α-synucleinopathy. These results delineate a beneficial function of treadmill exercise in reducing α-syn spreading in the brain via PPARα.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Mice; Physical Conditioning, Animal; PPAR alpha; Substantia Nigra; Synucleinopathies

Intraneuronal inclusions of misfolded α-synuclein (α-syn) and prion-like spread of the pathologic α-syn contribute to progressive neuronal death in Parkinson's disease (PD). Despite the pathologic significance, no efficient therapeutic intervention targeting α-synucleinopathy has been developed. In this study, we provide evidence that astrocytes, especially those cultured from the ventral midbrain (VM), show therapeutic potential to alleviate α-syn pathology in multiple in vitro and in vivo α-synucleinopathic models. Regulation of neuronal α-syn proteostasis underlies the therapeutic function of astrocytes. Specifically, VM-derived astrocytes inhibited neuronal α-syn aggregation and transmission in a paracrine manner by correcting not only intraneuronal oxidative and mitochondrial stresses but also extracellular inflammatory environments, in which α-syn proteins are prone to pathologic misfolding. The astrocyte-derived paracrine factors also promoted disassembly of extracellular α-syn aggregates. In addition to the aggregated form of α-syn, VM astrocytes reduced total α-syn protein loads both by actively scavenging extracellular α-syn fibrils and by a paracrine stimulation of neuronal autophagic clearance of α-syn. Transplantation of VM astrocytes into the midbrain of PD model mice alleviated α-syn pathology and protected the midbrain dopamine neurons from neurodegeneration. We further showed that cografting of VM astrocytes could be exploited in stem cell-based therapy for PD, in which host-to-graft transmission of α-syn pathology remains a critical concern for long-term cell therapeutic effects.

Topics: alpha-Synuclein; Animals; Astrocytes; Brain Tissue Transplantation; Disease Models, Animal; Dopaminergic Neurons; Mesencephalon; Mice; Parkinson Disease; Proteostasis

The deposition of β-amyloid peptides and of α-synuclein proteins is a neuropathological hallmark in the brains of Alzheimer's disease (AD) and Parkinson's disease (PD) subjects, respectively. However, there is accumulative evidence that both proteins are not exclusive for their clinical entity but instead co-exist and interact with each other. Here, we investigated the presence of a newly identified, pyroglutamate79-modified α-synuclein variant (pGlu79-aSyn)-along with the enzyme matrix metalloproteinase-3 (MMP-3) and glutaminyl cyclase (QC) implicated in its formation-in AD and in the transgenic Tg2576 AD mouse model. In the human brain, pGlu79-aSyn was detected in cortical pyramidal neurons, with more distinct labeling in AD compared to control brain tissue. Using immunohistochemical double and triple labelings and confocal laser scanning microscopy, we demonstrate an association of pGlu79-aSyn, MMP-3 and QC with β-amyloid plaques. In addition, pGlu79-aSyn and QC were present in amyloid plaque-associated reactive astrocytes that were also immunoreactive for the chaperone heat shock protein 27 (HSP27). Our data are consistent for the transgenic mouse model and the human clinical condition. We conclude that pGlu79-aSyn can be generated extracellularly or within reactive astrocytes, accumulates in proximity to β-amyloid plaques and induces an astrocytic protein unfolding mechanism involving HSP27.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Disease Models, Animal; HSP27 Heat-Shock Proteins; Humans; Matrix Metalloproteinase 3; Mice; Mice, Transgenic; Plaque, Amyloid

Ubiquitin-Specific Protease-13 (USP13) promotes protein de-ubiquitination. USP13 levels are upregulated in post-mortem Parkinson's disease, whereas USP13 knockdown via shRNA reduces alpha-synuclein levels in animal models. We studied the role of USP13 in knockout mice expressing lentiviral human alpha-synuclein and investigated the impact of a small molecule inhibitor of USP13, BK50118-C, on alpha-synuclein pathology and animal behavior. Alpha-synuclein was expressed unilaterally in substantia nigra (SN) of USP13 deficient mice that were treated with a daily intraperitoneal injection of 100 mg/kg BK50118-C or DMSO for four consecutive weeks, and behavioral and functional assays were performed. Wild-type USP13

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; Substantia Nigra; Ubiquitin-Specific Proteases

Parkinson's disease (PD) is a neurodegenerative disease characterized by inclusions of aggregated α-synuclein (α-Syn). Oxidative stress plays a critical role in nigrostriatal degeneration and is responsible for α-Syn aggregation in PD. Vitamin C or ascorbic acid acts as an effective antioxidant to prevent free radical damage. However, vitamin C is easily oxidized and often loses its physiological activity, limiting its therapeutic potential. The objective of this study was to evaluate whether NXP031, a new compound we developed consisting of Aptamin C and Vitamin C, is neuroprotective against α-synucleinopathy. To model α-Syn induced PD, we stereotactically injected AAV particles overexpressing human α-Syn into the substantia nigra (SN) of mice. One week after AAV injection, NXP031 was administered via oral gavage every day for eight weeks. We found that oral administration of NXP031 ameliorated motor deficits measured by the rotarod test and prevented the loss of nigral dopaminergic neurons caused by WT-α-Syn overexpression in the SN. Also, NXP031 blocked the propagation of aggregated α-Syn into the hippocampus by alleviating oxidative stress. These results indicate that NXP031 can be a potential therapeutic for PD.

Topics: alpha-Synuclein; Animals; Ascorbic Acid; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Mice; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is a progressive motor neurodegenerative disorder significantly associated with protein aggregation related neurodegenerative mechanisms. In view of no disease modifying drugs, the present study was targeted to investigate the therapeutic effects of pharmacological agent 4-phenylbutyric acid (4PBA) in PD pathology. 4PBA is an FDA approved monocarboxylic acid with inhibitory activity towards histone deacetylase and clinically treats urea cycle disorder. First, we observed the significant protective effects of 4PBA on PD specific neuromuscular coordination, level of tyrosine hydroxylase, α-synuclein level and neurotransmitter dopamine in both substantia nigra and striatal regions of the experimental rat model of PD. Further results revealed that treatment with 4PBA drug exhibited significant protection against disease related oxidative stress and augmented nitrite levels. The disease pathology-related depletion in mitochondrial membrane potential and augmented level of calcium as well as mitochondrion membrane located VDAC1 protein level and cytochrome-c translocation were also significantly attenuated with 4PBA administration. Inhibited neuronal apoptosis and restored neuronal morphology were also observed with 4PBA treatment as measured by level of pro-apoptotic proteins t-Bid, Bax and cleaved caspase-3 along with cresyl violet staining in both substantia nigra and striatal regions. Lastly, PD-linked astrocyte activation was significantly inhibited with 4PBA treatment. Altogether, our findings suggest that 4PBA exerts broad-spectrum neuroprotective effects in PD animal model.

Topics: alpha-Synuclein; Animals; Astrocytes; bcl-2-Associated X Protein; Calcium; Caspase 3; Cytochromes; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Histone Deacetylases; Mitochondria; Motor Disorders; Neuroprotective Agents; Nitrites; Parkinson Disease; Phenylbutyrates; Protein Aggregates; Rats; Tyrosine 3-Monooxygenase; Voltage-Dependent Anion Channel 1

Parkinson disease (PD) and Alzheimer's disease (AD) are progressive neurodegenerative disorders characterized by loss of selective neurons in discreet part of the brain. The peptide angiotensin II (Ang II) plays significant role in hippocampal and striatal neurons degeneration through the generation of reactive oxygen species. Blockade of the angiotensin converting enzyme or ATI receptors provides protection in animal models of neurodegenerative diseases. In the present study, the neuroprotective effect of captopril was investigated in Drosophila melanogaster model using the UAS-GAL4 system to express the synuclein and Aβ42 peptide in the flies' neurons.. The disease causing human Aβ42 peptide or α-syn was expressed pan-neuronally (elav-GAL4) or dopamine neuron (DDC-GAL4) using the UAS-GAL4 system. Flies were either grown in food media with or without captopril (1, 5, or 10µM). This was followed by fecundity, larva motility, negative geotaxis assay (climbing) and lifespan as a measure of neurodegeneration.. Elav-Gal4

Topics: alpha-Synuclein; Angiotensin-Converting Enzyme Inhibitors; Animals; Captopril; Disease Models, Animal; Drosophila melanogaster; Humans; Models, Genetic; Neurodegenerative Diseases; Neurons

Pathological protein inclusion formation and propagation are the main causes of neuronal dysfunction in diverse neurodegenerative diseases; therefore, current disease-modifying therapeutic strategies have targeted this disease protein aggregation process. Recently, we reported that peucedanocoumarin III (PCiii) is a promising therapeutic compound with the ability to disaggregate α-synuclein inclusion and protect dopaminergic neurons in Parkinson's disease (PD). Here, we found that

Topics: alpha-Synuclein; Animals; Coumarins; Disease Models, Animal; Dopaminergic Neurons; Mice; Parkinson Disease; Rats; Synucleinopathies

Parkinson's disease (PD) is characterized by degeneration of nigrostriatal dopaminergic neurons and accumulation of α-synuclein (αSyn) as Lewy bodies. Currently, there is no disease-modifying therapy available for PD. We have shown that a small molecular inhibitor for prolyl oligopeptidase (PREP), KYP-2047, relieves αSyn-induced toxicity in various PD models by inducing autophagy and preventing αSyn aggregation. In this study, we wanted to study the effects of PREP inhibition on different αSyn species by using cell culture and in vivo models. We used Neuro2A cells with transient αSyn overexpression and oxidative stress or proteasomal inhibition-induced αSyn aggregation to assess the effect of KYP-2047 on soluble αSyn oligomers and on cell viability. Here, the levels of soluble αSyn were measured by using ELISA, and the impact of KYP-2047 was compared to anle138b, nilotinib and deferiprone. To evaluate the effect of KYP-2047 on αSyn fibrillization in vivo, we used unilateral nigral AAV1/2-A53T-αSyn mouse model, where the KYP-2047 treatment was initiated two- or four-weeks post injection. KYP-2047 and anle138b protected cells from αSyn toxicity but interestingly, KYP-2047 did not reduce soluble αSyn oligomers. In AAV-A53T-αSyn mouse model, KYP-2047 reduced significantly proteinase K-resistant αSyn oligomers and oxidative damage related to αSyn aggregation. However, the KYP-2047 treatment that was initiated at the time of symptom onset, failed to protect the nigrostriatal dopaminergic neurons. Our results emphasize the importance of whole αSyn aggregation process in the pathology of PD and raise an important question about the forms of αSyn that are reasonable targets for PD drug therapy.

Topics: alpha-Synuclein; Animals; Cell Survival; Disease Models, Animal; Endopeptidase K; Mice; Parkinson Disease; Prolyl Oligopeptidases

Parkinson's disease is a neurodegenerative disorder that involves the death of the dopaminergic neurons of the nigrostriatal pathway and, consequently, the progressive loss of control of voluntary movements. This neurodegenerative process is triggered by the deposition of protein aggregates in the brain, which are mainly constituted of α-synuclein. Several studies have indicated that neuroinflammation is required to develop the neurodegeneration associated with Parkinson's disease. Notably, the neuroinflammatory process involves microglial activation as well as the infiltration of peripheral T cells into the substantia nigra (SN). This work analyzes a mouse model of Parkinson's disease that recapitulates microglial activation, T-cell infiltration into the SN, the neurodegeneration of nigral dopaminergic neurons, and motor impairment. This mouse model of Parkinson's disease is induced by the stereotaxic delivery of adeno-associated viral vectors encoding the human wild-type α-synuclein (AAV-hαSyn) into the SN. The correct delivery of viral vectors into the SN was confirmed using control vectors encoding green fluorescent protein (GFP). Afterward, how the dose of AAV-hαSyn administered in the SN affected the extent of hαSyn expression, the loss of nigral dopaminergic neurons, and motor impairment were evaluated. Moreover, the dynamics of hαSyn expression, microglial activation, and T-cell infiltration were determined throughout the time course of disease development. Thus, this study provides critical time points that may be useful for targeting synuclein pathology and neuroinflammation in this preclinical model of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Genetic Vectors; Humans; Mice; Parkinson Disease; Substantia Nigra

The fine-tuning of gene expression is critical for all cellular processes; aberrations in this activity can lead to pathology, and conversely, resilience. As their role in coordinating organismal responses to both internal and external factors have increasingly come into focus, small non-coding RNAs have emerged as an essential component to disease etiology. Using Systemic RNA interference Defective (SID) mutants of the nematode Caenorhabditis elegans, deficient in gene silencing, we examined the potential consequences of dysfunctional epigenomic regulation in the context of Parkinson's disease (PD). Specifically, the loss of either the sid-1 or sid-3 genes, which encode a dsRNA transporter and an endocytic regulatory non-receptor tyrosine kinase, respectively, conferred neuroprotection to dopaminergic (DA) neurons in an established transgenic C. elegans strain wherein overexpression of human α-synuclein (α-syn) from a chromosomally integrated multicopy transgene causes neurodegeneration. We further show that knockout of a specific microRNA, mir-2, attenuates α-syn neurotoxicity; suggesting that the native targets of mir-2-dependent gene silencing represent putative neuroprotective modulators. In support of this, we demonstrated that RNAi knockdown of multiple mir-2 targets enhanced α-syn-induced DA neurodegeneration. Moreover, we demonstrate that mir-2 overexpression originating in the intestine can induce neurodegeneration of DA neurons, an effect that was reversed by pharmacological inhibition of SID-3 activity. Interestingly, sid-1 mutants retained mir-2-induced enhancement of neurodegeneration. Transcriptomic analysis of α-syn animals with and without a sid-1 mutation revealed 27 differentially expressed genes with human orthologs related to a variety of diseases, including PD. Among these was pgp-8, encoding a P-glycoprotein-related ABC transporter. Notably, sid-1; pgp-8 double mutants abolished the neurodegeneration resulting from intestinal mir-2 overexpression. This research positions known regulators of small RNA-dependent gene silencing within a framework that facilitates mechanistic evaluation of epigenetic responses to exogenous and endogenous factors influencing DA neurodegeneration, revealing a path toward new targets for therapeutic intervention of PD.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Parkinson Disease; RNA Interference; RNA, Double-Stranded

In order to maintain cellular homeostasis and a healthy state, aberrant and aggregated proteins are to be recognized and rapidly cleared from cells. Parkinson's disease, known to be associated with multiple factors; presents with impaired clearance of aggregated alpha synuclein as a key factor. We endeavored to study microRNA molecules with potential role on regulating multiple checkpoints of protein quality control within cells. Carrying out global miRNA profiling in a transgenic C. elegans model that expresses human alpha synuclein, we identified novel miRNA, miR-4813-3p, as a significantly downregulated molecule. Further studying its putative downstream target genes, we were able to mechanistically characterize six genes gbf-1, vha-5, cup-5, cpd-2, acs-1 and C27A12.7, which relate to endpoints associated with alpha synuclein expression, oxidative stress, locomotory behavior, autophagy and apoptotic pathways. Our study reveals the novel role of miR-4813-3p and provides potential functional characterization of its putative target genes, in regulating the various pathways associated with PQC network. miR-4813-3p modulates ER

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Humans; Membrane Proteins; MicroRNAs; Parkinson Disease; Ubiquitins

Physical activity provides clinical benefit in Parkinson's disease (PD). Irisin is an exercise-induced polypeptide secreted by skeletal muscle that crosses the blood-brain barrier and mediates certain effects of exercise. Here, we show that irisin prevents pathologic α-synuclein (α-syn)-induced neurodegeneration in the α-syn preformed fibril (PFF) mouse model of sporadic PD. Intravenous delivery of irisin via viral vectors following the stereotaxic intrastriatal injection of α-syn PFF cause a reduction in the formation of pathologic α-syn and prevented the loss of dopamine neurons and lowering of striatal dopamine. Irisin also substantially reduced the α-syn PFF-induced motor deficits as assessed behaviorally by the pole and grip strength test. Recombinant sustained irisin treatment of primary cortical neurons attenuated α-syn PFF toxicity by reducing the formation of phosphorylated serine 129 of α-syn and neuronal cell death. Tandem mass spectrometry and biochemical analysis revealed that irisin reduced pathologic α-syn by enhancing endolysosomal degradation of pathologic α-syn. Our findings highlight the potential for therapeutic disease modification of irisin in PD.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Fibronectins; Mice; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease, after Alzheimer's disease, and becomes increasingly prevalent with age. α-Synuclein (α-syn) forms the major filamentous component of Lewy bodies, which are pathological hallmarks of α-synucleinopathies such as PD. We evaluated the neuroprotective effects of MT101-5, a standardized herbal formula that consists of an ethanolic extract of Genkwae Flos, Clematidis Radix, and Gastrodiae Rhizoma, against α-synuclein-induced cytotoxicity in vivo. MT101-5 protected against behavioral deficits and loss of dopaminergic neurons in human α-syn-overexpressing transgenic mice after treatment with 30 mg/kg/day for 5 months. We investigated transcriptomic changes within MT101-5 mechanisms of action (MOA) suppressing α-syn aggregation in an α-synuclein preformed fibril (α-syn PFF) mouse model of sporadic PD. We found that inhibition of α-syn fibril formation was associated with changes in transcripts in mitochondrial biogenesis, electron transport, chaperones, and proteasomes following treatment with MT101-5. These results suggest that the mixed herbal formula MT101-5 may be used as a pharmaceutical agent for preventing or improving PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease

Although ɑ-synuclein (ɑ-syn) spreading in age-related neurodegenerative diseases such as Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) has been extensively investigated, the role of aging in the manifestation of disease remains unclear.. We explored the role of aging and inflammation in the pathogenesis of synucleinopathies in a mouse model of DLB/PD initiated by intrastriatal injection of ɑ-syn preformed fibrils (pff).. We found that aged mice showed more extensive accumulation of ɑ-syn in selected brain regions and behavioral deficits that were associated with greater infiltration of T cells and microgliosis. Microglial inflammatory gene expression induced by ɑ-syn-pff injection in young mice had hallmarks of aged microglia, indicating that enhanced age-associated pathologies may result from inflammatory synergy between aging and the effects of ɑ-syn aggregation. Based on the transcriptomics analysis projected from Ingenuity Pathway Analysis, we found a network that included colony stimulating factor 2 (CSF2), LPS related genes, TNFɑ and poly rl:rC-RNA as common regulators.. We propose that aging related inflammation (eg: CSF2) influences outcomes of pathological spreading of ɑ-syn and suggest that targeting neuro-immune responses might be important in developing treatments for DLB/PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Inflammation; Mice; Parkinson Disease; Synucleinopathies

Parkinson's disease is a neurodegenerative disease, the etiology of which remains unknown, but some likely causes include oxidative stress, mitochondrial dysfunction and neuroinflammation. Peroxisome-proliferator-activated receptor (PPAR) agonists have been studied in animal models of Parkinson's disease and have shown neuroprotective effects. In this study, we aimed to (1) confirm the neuroprotective effects of PPAR-alpha agonist fenofibrate. To this end, male rats received fenofibrate (100 mg/kg) orally for 15 days, 5 days before the intraperitoneal injections of rotenone (2.5 mg/kg for 10 days). After finishing the treatment with rotenone and fenofibrate, animals were subjected to the open field, the forced swim test and the two-way active avoidance task. Subsequently, rats were euthanized for measurement of dopamine and metabolites levels in the striatum and quantification of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra pars compacta (SNpc). In addition, we aimed to (2) evaluate the neuroprotective effects of fenofibrate on the accumulation of α-synuclein aggregates. Here, rats were treated for 5 days with fenofibrate continuing for over 28 days with rotenone. Then, animals were perfused for immunohistochemistry analysis of α-synuclein. The results showed that fenofibrate reduced depressive-like behavior and memory impairment induced by rotenone. Moreover, fenofibrate diminished the depletion of striatal dopamine and protected against dopaminergic neuronal death in the SNpc. Likewise, the administration of fenofibrate attenuated the aggregation of α-synuclein in the SNpc and striatum in the rotenone-lesioned rats. Our study confirmed that fenofibrate exerted neuroprotective effects because parkinsonian rats exhibited reduced behavioral, neurochemical and immunohistochemical changes, and importantly, a lower number of α-synuclein aggregates.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Fenofibrate; Male; Neurodegenerative Diseases; Neuroprotection; Neuroprotective Agents; Parkinson Disease; Peroxisome Proliferator-Activated Receptors; Rats; Rotenone; Substantia Nigra

Parkinson disease (PD) is the second most progressive neurodegenerative disorder of the central nervous system (CNS) in the elderly, causing motor impediments and cognitive dysfunctions. Dopaminergic (DA) neuron degeneration and α-synuclein (α-Syn) accumulation in substantia nigra pars compacta (SNPc) are the major contributor to this disease. At present, the disease has no effective treatment. Many recent studies focus on identifying novel therapeutics that provide benefits to stop disease advancement in PD patients. Cannabidiol (CBD) is a cannabinoid derived from the Cannabis sativa plant and possesses anti-depressive, anti-inflammatory, and antioxidative effects. The present study aims to evaluate the neuroprotective effect of CBD in transgenic C. elegans PD models. We observed that CBD at 0.025 mM (24.66 %), 0.05 mM (52.41 %) and 0.1 mM (71.36 %) diminished DA neuron degenerations induced by 6-hydroxydopamine (6-OHDA), reduced (0.025, 27.1 %), (0.05, 38.9 %), (0.1, 51.3 %) food-sensing behavioural disabilities in BZ555, reduced 40.6 %, 56.3 %, 70.2 % the aggregative toxicity of α-Syn and expanded the nematodes' lifespan up to 11.5 %, 23.1 %, 28.8 %, dose-dependently. Moreover, CBD augmented the ubiquitin-like proteasomes 28.11 %, 43.27, 61.33 % and SOD-3 expressions by about 16.4 %, 21.2 %, 44.8 % in transgenic models. Further, we observed the antioxidative role of CBD by reducing 33.2 %, 41.4 %, 56.7 % reactive oxygen species in 6-OHDA intoxicated worms. Together, these findings supported CBD as an anti-parkinsonian drug and may exert its effects by raising lipid depositions to enhance proteasome activity and reduce oxidative stress via the antioxidative pathway.

Topics: alpha-Synuclein; Animals; Antioxidants; Caenorhabditis elegans; Cannabidiol; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Neuroprotective Agents; Oxidopamine; Parkinson Disease

Studies have shown different gut microbiomes in patients with Parkinson's disease (PD) compared to unaffected controls. However, when the gut microbiota shift toward dysbiosis in the PD process remains unclear.. We aim to investigate the changes in gut microbiota, locomotor function, and neuropathology longitudinally in PD rodent models.. Fecal microbiota were longitudinally assessed by sequencing the V4-V5 region of the 16S ribosomal RNA gene in a human mutant α-synuclein over-expressing mouse model of PD, SNCA p.A53T mice, and the non-transgenic littermate controls. The locomotor function, neuronal integrity, and α-synuclein expression in the different brain regions were compared between groups. Human fecal microbiota communities from 58 patients with PD and 46 unaffected controls were also analyzed using metagenomic sequencing for comparison.. Compared to non-transgenic littermate controls, the altered gut microbiota of the SNCA p.A53T mice can be detected as early as 2 months old, and the diurnal oscillation of the gut microbiome was dampened throughout PD progression starting from 4 months old. However, neuropathology changes and motor deficits were observed starting at 6 months old. Similar changes in altered gut microbiota were also observed in another PD genetic mouse model carrying the LRRK2 p.G2019S mutation at 2 months old. Among the commonly enriched gut microbiota in both PD genetic mouse models, the abundance of Parabateroides Merdae and Ruminococcus torques were also increased in human PD patients compared to controls.. These findings revealed the altered gut microbiota communities and oscillations preceding the occurrence of neuropathy and motor dysfunction in the PD process.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dysbiosis; Gastrointestinal Microbiome; Humans; Infant; Mice; Parkinson Disease

Systemic and neuroinflammatory processes play key roles in neurodegenerative diseases such as Parkinson's disease (PD). Physical trauma which induces considerable systemic inflammatory responses, represents an evident environmental factor in aging. However, little is known about the impact of physical trauma, on the immuno-pathophysiology of PD. Especially blunt chest trauma which is associated with a high morbidity and mortality rate in the elderly population, can induce a strong pulmonary and systemic inflammatory reaction. Hence, we sought out to combine a well-established thoracic trauma mouse model with a well-established PD mouse model to characterize the influence of physical trauma to neurodegenerative processes in PD.. To study the influence of peripheral trauma in a PD mouse model we performed a highly standardized blunt thorax trauma in a well-established PD mouse model and determined the subsequent local and systemic response.. We could show that blunt chest trauma leads to a systemic inflammatory response which is quantifiable with increased inflammatory markers in bronchoalveolar fluids (BALF) and plasma regardless of the presence of a PD phenotype. A difference of the local inflammatory response in the brain between the PD group and non-PD group could be detected, as well as an increase in the formation of oligomeric pathological alpha-Synuclein (asyn) suggesting an interplay between peripheral thoracic trauma and asyn pathology in PD.. Taken together this study provides evidence that physical trauma is associated with increased asyn oligomerization in a PD mouse model underlining the relevance of PD pathogenesis under traumatic settings.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Parkinson Disease; Thoracic Injuries; Wounds, Nonpenetrating

In the rat model, 6-hydroxydopamine (6-OHDA) known as a selective catecholaminergic neurotoxin used chiefly in modeling Parkinson's disease (PD). Continuous aerobic exercise and curcumin supplementations could play a vital role in neuroprotection. This study aimed to explore the neuroprotective roles of regular aerobic exercise and curcumin during PD. For this, rats were treated as follows for 8 consecutive weeks (5 d in a week): For this, animals were orally treated with curcumin (50 ml/kg) alone or in combination with aerobic exercise. Compared with a control group, induction of PD by 6-OHDA increased the amount of alpha-synuclein protein and malondialdehyde levels and decreased the number of substantia nigra neurons, total antioxidant capacity, and glutathione peroxidase activity in brain tissue. All these changes were abolished by the administration of curcumin with aerobic exercise treatments. Activity behavioral tests also confirmed the above-mentioned results by increasing the rod test time and the number of rotations due to apomorphine injection. Histopathology assays mimic the antioxidant activity and behavioral observations. Combined curcumin with aerobic exercise treatments is potentially an effective strategy for modifying the dopaminergic neuron dysfunction in 6-OHDA-induced rats modeling PD via dual inhibiting oxidative stress indices and regulating behavioral tasks.

Topics: alpha-Synuclein; Animals; Antioxidants; Apomorphine; Curcumin; Disease Models, Animal; Glutathione Peroxidase; Malondialdehyde; Neuroprotective Agents; Neurotoxicity Syndromes; Neurotoxins; Oxidopamine; Parkinson Disease; Rats; Substantia Nigra

Age-related neurodegenerative diseases (NDDs) are associated with the aggregation and propagation of specific pathogenic protein species (e.g., Aβ, α-synuclein). However, whether disruption of synaptic homeostasis results from protein misfolding per se rather than accumulation of a specific rogue protein is an unexplored question. Here, we show that error-prone translation, with its frequent outcome of random protein misfolding, is sufficient to recapitulate many early features of NDDs, including perturbed Ca

Topics: Aging; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Disease Models, Animal; Glucose; Memory Disorders; Mice; Mice, Transgenic

One of the most common types of neurodegenerative diseases (NDDs) is Lewy body disease (LBD), which is characterized by excessive accumulation of α-synuclein (α-syn) in the neurons and affects around 6 million individuals globally. In recent years, due to the environmental factors that can affect the development of this condition, such as exposure to herbicides and pesticides, so it has become a younger disease. Currently, the vast majority of studies on the neurotoxic effects of paraquat (PQ) focus on the late mechanisms of neuronal-glial network regulation, and little is known about the early origins of this environmental factor leading to LBD.. To observe the effect of PQ exposure on intestinal function and to explore the key components of communicating the gut-brain axis by establishing a mouse model.. In this study, C57BL/6J mice were treated by intraperitoneal injection of 15 mg/kg PQ to construct an LBD time-series model, and confirmed by neurobehavioral testing and pathological examination. After PQ exposure, on the one hand, we found that fecal particle counts and moisture content were abnormal. on the other hand, we found that the expression levels of colonic tight junction proteins decreased, the expression levels of inflammatory markers increased, and the diversity and abundance of gut microbiota altered. In addition, pathological aggregation of α-syn was consistent in the colon and midbrain, and the metabolism and utilization of short-chain fatty acids (SCFAs) were also markedly altered. This suggests that pathological α-syn and SCFAs form the gut may be key components of the communicating gut-brain axis.. In this PQ-induced mouse model, gut microbiota disruption, intestinal epithelial barrier damage, and inflammatory responses may be the main causes of gut dysfunction, and pathological α-syn and SCFAs in the gut may be key components of the communicating gut-brain axis.

Topics: alpha-Synuclein; Animals; Central Nervous System; Disease Models, Animal; Fatty Acids, Volatile; Intestinal Diseases; Mice; Mice, Inbred C57BL; Paraquat

Growing evidence for the importance of the gut-brain axis in Parkinson's disease (PD) has attracted researchers' interest in the possible application of microbiota-based treatment approaches. Using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model, we looked into the prospect of treating PD with fucosylated chondroitin sulfate obtained from sea cucumbers

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Chondroitin Sulfates; Disease Models, Animal; DNA, Bacterial; Dopamine; Dysbiosis; Inflammation; Intestines; Mice; Mice, Inbred C57BL; NF-kappa B; Parkinson Disease; Polysaccharides; RNA, Ribosomal, 16S; Sea Cucumbers

The α-synucleinopathies constitute a subset of neurodegenerative disorders, of which Parkinson's disease (PD) is the most common worldwide, characterized by the accumulation of misfolded α-synuclein in the cytoplasm of neurons, which spreads in a prion-like manner to anatomically interconnected brain areas. However, it is not clear how α-synucleinopathy triggers neurodegeneration. We recently developed a rat model through a single intranigral administration of the neurotoxic β-sitosterol β-D-glucoside (BSSG), which produces α-synucleinopathy. In this model, we aimed to evaluate the temporal pattern of levels in oxidative and nitrosative stress and mitochondrial complex I (CI) dysfunction and how these biochemical parameters are associated with neurodegeneration in different brain areas with α-synucleinopathy (

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Electron Transport Complex I; Mitochondria; Nitrosative Stress; Oxidative Stress; Peroxisome Proliferator-Activated Receptors; Rats; Synucleinopathies

Two of the primary features of Parkinson's disease (PD) are the accumulation of α-synuclein (α-Syn) and the depletion of lysosomal-associated membrane protein 1 (LAMP1) in the brain. Beneficial effects of environmental enrichment (EE) have been reported on the activation of lysosomal function and the amelioration of PD symptoms. Furthermore, Reelin could be a novel therapeutic target in PD. Hence, in this study, we validated the effects of EE on the activation of LAMP1 via Reelin in PD. Heterogeneous α-Syn (A53T)-overexpressing transgenic mice (age 6 and 16 months) were exposed to EE for 8 weeks. After motor and cognitive tests, brain tissues were obtained from mice and subjected to immunohistochemistry and molecular analyses. EE ameliorated motor and non-motor symptoms, protected dopamine neurons, and reduced pathological α-Syn accumulation in the early stage of PD. Striatal Reelin levels were altered depending on the disease stage and regulated by EE in PD mice. To elucidate the underlying mechanism of the effect of EE on PD, we performed further molecular and cellular analyses using activated preformed fibril (PFF)-induced SH-SY5Y cells, an in vitro model of PD, which were treated with recombinant Reelin protein and a Reelin blocker, CR-50. The CR-50 increased pathological α-Syn accumulation and accelerated dopamine neuronal degeneration by decreasing LAMP1 in the PFF-induced PD model. Our results showed that Reelin increased LAMP1 after EE and decreased pathological α-Syn accumulation, thus protecting dopamine neurons from degeneration in the striatum and substantia nigra, and ameliorating neurobehavioral deficits. These results suggest that Reelin is a promising target in treating histopathological changes and improving behavioral symptoms associated with PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Mice; Mice, Transgenic; Neuroblastoma; Parkinson Disease; Substantia Nigra

Oral rotenone has been proposed as a model for Parkinson's disease (PD) in mice. To establish the model in our lab and study complex behavior we followed a published treatment regimen. C57BL/6 mice received 30 mg/kg body weight of rotenone once daily via oral administration for 4 and 8 weeks. Motor functions were assessed by RotaRod running. Immunofluorescence studies were used to analyze the morphology of dopaminergic neurons, the expression of alpha-Synuclein (α-Syn), and inflammatory gliosis or infiltration in the substantia nigra. Rotenone-treated mice did not gain body weight during treatment compared with about 4 g in vehicle-treated mice, which was however the only robust manifestation of drug treatment and suggested local gut damage. Rotenone-treated mice had no deficits in motor behavior, no loss or sign of degeneration of dopaminergic neurons, no α-Syn accumulation, and only mild microgliosis, the latter likely an indirect remote effect of rotenone-evoked gut dysbiosis. Searching for explanations for the model failure, we analyzed rotenone plasma concentrations via LC-MS/MS 2 h after administration of the last dose to assess bioavailability. Rotenone was not detectable in plasma at a lower limit of quantification of 2 ng/mL (5 nM), showing that oral rotenone had insufficient bioavailability to achieve sustained systemic drug levels in mice. Hence, oral rotenone caused local gastrointestinal toxicity evident as lack of weight gain but failed to evoke behavioral or biological correlates of PD within 8 weeks.

Topics: alpha-Synuclein; Animals; Body Weight; Chromatography, Liquid; Disease Models, Animal; Mice; Mice, Inbred C57BL; Parkinson Disease; Parkinsonian Disorders; Rotenone; Substantia Nigra; Tandem Mass Spectrometry

Parkinson's disease (PD) is a movement disorder characterized by neuroinflammation, α-synuclein pathology, and neurodegeneration. Most cases of PD are non-hereditary, suggesting a strong role for environmental factors, and it has been speculated that disease may originate in peripheral tissues such as the gastrointestinal (GI) tract before affecting the brain. The gut microbiome is altered in PD and may impact motor and GI symptoms as indicated by animal studies, although mechanisms of gut-brain interactions remain incompletely defined. Intestinal bacteria ferment dietary fibers into short-chain fatty acids, with fecal levels of these molecules differing between PD and healthy controls and in mouse models. Among other effects, dietary microbial metabolites can modulate activation of microglia, brain-resident immune cells implicated in PD. We therefore investigated whether a fiber-rich diet influences microglial function in α-synuclein overexpressing (ASO) mice, a preclinical model with PD-like symptoms and pathology. Feeding a prebiotic high-fiber diet attenuates motor deficits and reduces α-synuclein aggregation in the substantia nigra of mice. Concomitantly, the gut microbiome of ASO mice adopts a profile correlated with health upon prebiotic treatment, which also reduces microglial activation. Single-cell RNA-seq analysis of microglia from the substantia nigra and striatum uncovers increased pro-inflammatory signaling and reduced homeostatic responses in ASO mice compared to wild-type counterparts on standard diets. However, prebiotic feeding reverses pathogenic microglial states in ASO mice and promotes expansion of protective disease-associated macrophage (DAM) subsets of microglia. Notably, depletion of microglia using a CSF1R inhibitor eliminates the beneficial effects of prebiotics by restoring motor deficits to ASO mice despite feeding a prebiotic diet. These studies uncover a novel microglia-dependent interaction between diet and motor symptoms in mice, findings that may have implications for neuroinflammation and PD.

Topics: alpha-Synuclein; Animals; Diet; Disease Models, Animal; Mice; Mice, Inbred C57BL; Microglia; Parkinson Disease; Prebiotics; Substantia Nigra

Accumulating evidence has shown that Parkinson's disease (PD) is a systemic disease other than a mere central nervous system (CNS) disorder. One of the most important peripheral symptoms is gastrointestinal dysfunction. The enteric nervous system (ENS) is regarded as an essential gateway to the environment. The discovery of the prion-like behavior of α-synuclein makes it possible for the neurodegenerative process to start in the ENS and spread via the gut-brain axis to the CNS. We first confirmed that synucleinopathies existed in the stomachs of chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/probenecid (MPTP/p)-induced PD mice, as indicated by the significant increase in abnormal aggregated and nitrated α-synuclein in the TH-positive neurons and enteric glial cells (EGCs) of the gastric myenteric plexus. Next, we attempted to clarify the mechanisms in single MPTP-injected mice. The stomach naturally possesses high monoamine oxidase-B (MAO-B) activity and low superoxide dismutase (SOD) activity, making the stomach susceptible to MPTP-induced oxidative stress, as indicated by the significant increase in reactive oxygen species (ROS) in the stomach and elevated 4-hydroxynonenal (4-HNE) in the EGCs after MPTP exposure for 3 h. Additionally, stomach synucleinopathies appear before those of the nigrostriatal system, as determined by Western blotting 12 h after MPTP injection. Notably, nitrated α-synuclein was considerably increased in the EGCs after 3 h and 12 h of MPTP exposure. Taken together, our work demonstrated that the EGCs could be new contributors to synucleinopathies in the stomach. The early-initiated synucleinopathies might further influence neighboring neurons in the myenteric plexus and the CNS. Our results offer a new experimental clue for interpreting the etiology of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Inbred C57BL; MPTP Poisoning; Neuroglia; Parkinson Disease; Parkinsonian Disorders; Stomach; Synucleinopathies

Cryptococcosis in the central nervous system (CNS) can present with motor declines described as Parkinsonism. Although several lines of evidence indicate that dopaminergic (DA) neuron degeneration and α-synuclein accumulation contribute to the hallmark of Parkinsonism and Parkinson's disease (PD), little is known about cryptococcal infections associated with neuronal degeneration. In this study, the effects of

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Cryptococcus; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Nerve Degeneration

Events associated with the progression of Parkinson´s disease (PD) are closely related to biomembrane dysfunction. The specific role of membrane composition in the conformational stability of alpha synuclein (αS) has already been well documented. Administration of rotenone is one of the best strategies to initiate PD phenotype in animal models. In the present study, daily exposure (14 weeks) of orally administered rotenone (10 mg/kg) was employed in a mouse model. The mitochondrial complex I inhibition resulted in elevated level of αS in whole tissue homogenate of mouse jejunum. In addition, we identified a strong intra-individual correlation between αS level and the specific esterified fatty acids. The observed correlation depends mainly on the acyl chain length. Based on the obtained results, it is suggested that there is a high potential to manipulate fatty acid homeostasis in modulating αS based pathogenesis of PD, at least in experimental conditions.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Fatty Acids; Jejunum; Mice; Parkinson Disease; Rotenone

The clinical progression of neurodegenerative diseases correlates with the spread of proteinopathy in the brain. The current understanding of the mechanism of proteinopathy spread is far from complete. Here, we propose that inflammation is fundamental to proteinopathy spread. A sequence variant of α-synuclein (V40G) was much less capable of fibril formation than wild-type α-synuclein (WT-syn) and, when mixed with WT-syn, interfered with its fibrillation. However, when V40G was injected intracerebrally into mice, it induced aggregate spreading even more effectively than WT-syn. Aggregate spreading was preceded by sustained microgliosis and inflammatory responses, which were more robust with V40G than with WT-syn. Oral administration of an anti-inflammatory agent suppressed aggregate spreading, inflammation, and behavioral deficits in mice. Furthermore, exposure of cells to inflammatory cytokines increased the cell-to-cell propagation of α-synuclein. These results suggest that the inflammatory microenvironment is the major driver of the spread of synucleinopathy in the brain.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Inflammation; Mice; Neurodegenerative Diseases; Synucleinopathies

Alpha-synuclein (aSyn) is a 14 kD protein encoded by the SNCA gene that is expressed in vertebrates and normally localizes to presynaptic terminals and the nucleus. aSyn forms pathological intracellular aggregates that typify a group of important neurodegenerative diseases called synucleinopathies. Previous work in human tissue and model systems indicates that some of these aggregates can be intranuclear, but the significance of aSyn aggregation within the nucleus is not clear. We used a mouse model that develops aggregated aSyn nuclear inclusions. Using aSyn preformed fibril injections in GFP-tagged aSyn transgenic mice, we were able to induce the formation of nuclear aSyn inclusions and study their properties in fixed tissue and in vivo using multiphoton microscopy. In addition, we analyzed human synucleinopathy patient tissue to better understand this pathology. Our data demonstrate that nuclear aSyn inclusions may form through the transmission of aSyn between neurons, and these intranuclear aggregates bear the hallmarks of cytoplasmic Lewy pathology. Neuronal nuclear aSyn inclusions can form rod-like structures that do not contain actin, excluding them from being previously described nuclear actin rods. Longitudinal, in vivo multiphoton imaging indicates that certain morphologies of neuronal nuclear aSyn inclusions predict cell death within 14 days. Human multiple system atrophy cases contain neurons and glia with similar nuclear inclusions, but we were unable to detect such inclusions in Lewy body dementia cases. This study suggests that the dysregulation of a nuclear aSyn function associated with nuclear inclusion formation could play a role in the forms of neurodegeneration associated with synucleinopathy.

Topics: Actins; alpha-Synuclein; Animals; Cell Death; Disease Models, Animal; Humans; Lewy Body Disease; Mice; Mice, Transgenic; Multiple System Atrophy; Synucleinopathies

Antisense oligonucleotide (ASO) therapy for neurological disease has been successful in clinical settings and its potential has generated hope for Alzheimer's disease (AD). We previously described that ablating SNCA encoding for α-synuclein (αSyn) in a mouse model of AD was beneficial. Here, we sought to demonstrate whether transient reduction of αSyn expression using ASO

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Cognition; Disease Models, Animal; Female; Gene Expression; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic

Regulatory CD4. Using the AAV1/2-A53T-α-synuclein Parkinson's disease mouse model that overexpresses the pathogenic human A53T-α-synuclein (hαSyn) variant in dopaminergic neurons of the substantia nigra, we assessed the neuroprotective and disease-modifying efficacy of a single intraperitoneal dose of CD28SA given at an early disease stage.. CD28SA led to Treg expansion 3 days after delivery in hαSyn Parkinson's disease mice. At this timepoint, an early pro-inflammation was observed in vehicle-treated hαSyn Parkinson's disease mice with elevated percentages of CD8. Our data indicate that immune modulation by Treg expansion at a timepoint of overt inflammation is effective for treatment of hαSyn Parkinson's disease mice and suggest that the concept of early immune therapy could pose a disease-modifying option for Parkinson's disease patients.

Topics: alpha-Synuclein; Animals; Antibodies; CD28 Antigens; CD8-Positive T-Lymphocytes; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Mice; Mice, Inbred C57BL; Parkinson Disease; Substantia Nigra; T-Lymphocytes, Regulatory

Parkinson's disease (PD) is characterized pathologically by alpha-synuclein (α-Syn) aggregates and clinically by the motor as well as cognitive deficits, including impairments in sequence learning and habit learning. Using intracerebral injection of WT and A53T mutant α-Syn fibrils, we investigate the behavioral mechanism of α-Syn for procedure-learning deficit in PD by critically determining the α-Syn-induced effects on model-based goal-directed behavior, model-free (probability-based) habit learning, and hierarchically organized sequence learning. 1) Contrary to the widely held view of habit-learning deficit in early PD, α-Syn aggregates in the dorsomedial striatum (DMS) and dorsolateral striatum (DLS) did not affect acquisition of habit learning, but selectively impaired goal-directed behavior with reduced value sensitivity. 2) α-Syn in the DLS (but not DMS) and SNc selectively impaired the sequence learning by affecting sequence initiation with the reduced first-step accuracy. 3) Adenosine A2A receptor (A2AR) antagonist KW6002 selectively improved sequence learning by preferentially improving sequence initiation and shift of sequence learning as well as behavioral reactivity. These findings established a casual role of α-Syn in the SN-DLS pathway in sequence-learning deficit and DMS α-Syn in goal-directed behavior deficit and suggest a novel therapeutic strategy to improve sequence-learning deficit in PD with enhanced sequence initiation by A2AR antagonists.

Topics: Adenosine A2 Receptor Antagonists; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Parkinson Disease; Receptor, Adenosine A2A

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. However, it is unclear whether microbiota and metabolites have demonstrated changes at early PD due to the difficulties in diagnosis and identification of early PD in clinical practice. In a previous study, we generated A53T transgenic monkeys with early Parkinson's symptoms, including anxiety and cognitive impairment. Here we analyzed the gut microbiota by metagenomic sequencing and metabolites by targeted gas chromatography. The gut microbiota analysis showed that the A53T monkeys have higher degree of diversity in gut microbiota with significantly elevated Sybergistetes, Akkermansia, and Eggerthella lenta compared with control monkeys. Prevotella significantly decreased in A53T transgenic monkeys. Glyceric acid, L-Aspartic acid, and p-Hydroxyphenylacetic acid were significantly elevated, whereas Myristic acid and 3-Methylindole were significantly decreased in A53T monkeys. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (KO0131) and the oxidative phosphorylation reaction (KO2147) were significantly increased in metabolic pathways of A53T monkeys. Our study suggested that the transgenic A53T and α-syn aggregation may affect the intestine microbiota and metabolites of rhesus monkeys, and the identified five compositional different metabolites that are mainly associated with mitochondrial dysfunction may be related to the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Female; Gastrointestinal Microbiome; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Macaca mulatta; Male; Metagenomics; Mice; Neurodegenerative Diseases; Parkinson Disease

Cell death is a critical process that occurs normally in health and disease. However, its study is limited due to available technologies that only detect very late stages in the process or specific death mechanisms. Here, we report the development of a family of fluorescent biosensors called genetically encoded death indicators (GEDIs). GEDIs specifically detect an intracellular Ca

Topics: alpha-Synuclein; Animals; Biosensing Techniques; Calcium; Cell Death; Cerebral Cortex; Disease Models, Animal; DNA-Binding Proteins; Embryo, Nonmammalian; Fluorescent Dyes; Gene Expression Regulation, Developmental; Genes, Reporter; Glutamic Acid; Green Fluorescent Proteins; Humans; Larva; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Primary Cell Culture; Rats; Rats, Long-Evans; Single-Cell Analysis; Superoxide Dismutase-1; Zebrafish

Parkinson's disease (PD) is characterized by a loss of dopaminergic cells in the substantia nigra, and its histopathological features include the presence of fibrillar aggregates of α-synuclein (α-syn), which are called Lewy bodies and Lewy neurites. Lewy pathology has been identified not only in the brain but also in various tissues, including muscles. This study aimed to investigate the link between serine/arginine-rich protein specific kinase 3 (

Topics: 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Cell Line; Disease Models, Animal; Male; Mice, Inbred C57BL; MPTP Poisoning; Muscle, Skeletal; Parkinson Disease; Protein Serine-Threonine Kinases

Topics: alpha-Synuclein; Animals; Brain; Corpus Striatum; Diphtheria Toxin; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Heparin-binding EGF-like Growth Factor; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; Parkinsonian Disorders; Substantia Nigra; Tyrosine 3-Monooxygenase

The misfolding of host-encoded proteins into pathological prion conformations is a defining characteristic of many neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, and Lewy body dementia. A current area of intense study is the way in which the pathological deposition of these proteins might influence each other, as various combinations of co-pathology between prion-capable proteins are associated with exacerbation of disease. A spectrum of pathological, genetic and biochemical evidence provides credence to the notion that amyloid β (Aβ) accumulation can induce and promote α-synuclein pathology, driving neurodegeneration.. To assess the interplay between α-synuclein and Aβ on protein aggregation kinetics, we crossed mice expressing human α-synuclein (M20) with APPswe/PS1dE9 transgenic mice (L85) to generate M20/L85 mice. We then injected α-synuclein preformed fibrils (PFFs) unilaterally into the hippocampus of 6-month-old mice, harvesting 2 or 4 months later.. Immunohistochemical analysis of M20/L85 mice revealed that pre-existing Aβ plaques exacerbate the spread and deposition of induced α-synuclein pathology. This process was associated with increased neuroinflammation. Unexpectedly, the injection of α-synuclein PFFs in L85 mice enhanced the deposition of Aβ; whereas the level of Aβ deposition in M20/L85 bigenic mice, injected with α-synuclein PFFs, did not differ from that of mice injected with PBS.. These studies reveal novel and unexpected interplays between α-synuclein pathology, Aβ and neuroinflammation in mice that recapitulate the pathology of Alzheimer's disease and Lewy body dementia.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Astrocytes; Cerebral Cortex; Crosses, Genetic; Dementia; Disease Models, Animal; Gliosis; Hippocampus; Humans; Injections; Lewy Body Disease; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Neuroinflammatory Diseases; Parkinson Disease; Prions; Protein Aggregates; Protein Aggregation, Pathological; Recombinant Proteins

Pathways to control the spreading of α-synuclein (α-syn) and associated neuropathology in Parkinson's disease (PD), multiple system atrophy (MSA) and dementia with Lewy bodies (DLB) are unclear. Here, we show that preformed α-syn fibrils (PFF) increase the association between TLR2 and MyD88, resulting in microglial activation. The TLR2-interaction domain of MyD88 (wtTIDM) peptide-mediated selective inhibition of TLR2 reduces PFF-induced microglial inflammation in vitro. In PFF-seeded A53T mice, the nasal administration of the wtTIDM peptide, NEMO-binding domain (wtNBD) peptide, or genetic deletion of TLR2 reduces glial inflammation, decreases α-syn spreading, and protects dopaminergic neurons by inhibiting NF-κB. In summary, α-syn spreading depends on the TLR2/MyD88/NF-κB pathway and it can be reduced by nasal delivery of wtTIDM and wtNBD peptides.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Humans; Lewy Body Disease; Mice; Mice, Knockout; Microglia; Multiple System Atrophy; Mutagenesis, Site-Directed; Mutation; Myeloid Differentiation Factor 88; NF-kappa B; Parkinson Disease; Primary Cell Culture; Promoter Regions, Genetic; Signal Transduction; Toll-Like Receptor 2

The evidence linking innate immunity mechanisms and neurodegenerative diseases is growing, but the specific mechanisms are incompletely understood. Experimental data suggest that microglial TLR4 mediates the uptake and clearance of α-synuclein also termed synucleinophagy. The accumulation of misfolded α-synuclein throughout the brain is central to Parkinson's disease (PD). The distribution and progression of the pathology is often attributed to the propagation of α-synuclein. Here, we apply a classical α-synuclein propagation model of prodromal PD in wild type and TLR4 deficient mice to study the role of TLR4 in the progression of the disease. Our data suggest that TLR4 deficiency facilitates the α-synuclein seed spreading associated with reduced lysosomal activity of microglia. Three months after seed inoculation, more pronounced proteinase K-resistant α-synuclein inclusion pathology is observed in mice with TLR4 deficiency. The facilitated propagation of α-synuclein is associated with early loss of dopamine transporter (DAT) signal in the striatum and loss of dopaminergic neurons in substantia nigra pars compacta of TLR4 deficient mice. These new results support TLR4 signaling as a putative target for disease modification to slow the progression of PD and related disorders.

Topics: alpha-Synuclein; Animals; Brain; Corpus Striatum; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; Dopaminergic Neurons; Lysosomes; Mice; Microglia; Nerve Degeneration; Parkinson Disease; Pars Compacta; Signal Transduction; Toll-Like Receptor 4

Multiple System Atrophy (MSA) is a rare neurodegenerative synucleinopathy which leads to severe disability followed by death within 6-9 years of symptom onset. There is compelling evidence suggesting that biological trace metals like iron and copper play an important role in synucleinopathies like Parkinson's disease and removing excess brain iron using chelators could slow down the disease progression. In human MSA, there is evidence of increased iron in affected brain regions, but role of iron and therapeutic efficacy of iron-lowering drugs in pre-clinical models of MSA have not been studied. We studied age-related changes in iron metabolism in different brain regions of the PLP-αsyn mice and tested whether iron-lowering drugs could alleviate disease phenotype in aged PLP-αsyn mice. Iron content, iron-ferritin association, ferritin protein levels and copper-ceruloplasmin association were measured in prefrontal cortex, putamen, substantia nigra and cerebellum of 3, 8, and 20-month-old PLP-αsyn and age-matched non-transgenic mice. Moreover, 12-month-old PLP-αsyn mice were administered deferiprone or ceruloplasmin or vehicle for 2 months. At the end of treatment period, motor testing and stereological analyses were performed. We found iron accumulation and perturbed iron-ferritin interaction in substantia nigra, putamen and cerebellum of aged PLP-αsyn mice. Furthermore, we found significant reduction in ceruloplasmin-bound copper in substantia nigra and cerebellum of the PLP-αsyn mice. Both deferiprone and ceruloplasmin prevented decline in motor performance in aged PLP-αsyn mice and were associated with higher neuronal survival and reduced density of α-synuclein aggregates in substantia nigra. This is the first study to report brain iron accumulation in a mouse model of MSA. Our results indicate that elevated iron in MSA mice may result from ceruloplasmin dysfunction and provide evidence that targeting iron in MSA could be a viable therapeutic option.

Topics: alpha-Synuclein; Animals; Brain; Cerebellum; Ceruloplasmin; Copper; Deferiprone; Disease Models, Animal; Ferritins; Iron; Iron Chelating Agents; Mice; Mice, Transgenic; Multiple System Atrophy; Prefrontal Cortex; Putamen; Substantia Nigra

Here, we utilize the stability of proteins from rates of oxidation (SPROX) technique, to profile the thermodynamic stabilities of proteins in brain tissue cell lysates from Huα-Syn(A53T) transgenic mice at three time points including at 1 month (

Topics: Aging; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Mice, Transgenic; Protein Stability; Synucleinopathies

Impairment in glucocerebrosidase (GCase) is strongly associated with the development of Parkinson's disease (PD), yet the regulators responsible for its impairment remain elusive. In this paper, we identify the E3 ligase Thyroid Hormone Receptor Interacting Protein 12 (TRIP12) as a key regulator of GCase. TRIP12 interacts with and ubiquitinates GCase at lysine 293 to control its degradation via ubiquitin proteasomal degradation. Ubiquitinated GCase by TRIP12 leads to its functional impairment through premature degradation and subsequent accumulation of α-synuclein. TRIP12 overexpression causes mitochondrial dysfunction, which is ameliorated by GCase overexpression. Further, conditional TRIP12 knockout in vitro and knockdown in vivo promotes the expression of GCase, which blocks α-synuclein preformed fibrils (α-syn PFFs)-provoked dopaminergic neurodegeneration. Moreover, TRIP12 accumulates in human PD brain and α-synuclein-based mouse models. The identification of TRIP12 as a regulator of GCase provides a new perspective on the molecular mechanisms underlying dysfunctional GCase-driven neurodegeneration in PD.

Topics: alpha-Synuclein; Animals; Brain; Carrier Proteins; Disease Models, Animal; Glucosylceramidase; Mice; Parkinson Disease; Ubiquitin-Protein Ligases; Ubiquitination

Aberrant α-synuclein (α-Syn) accumulation resulting from proteasome dysfunction is considered as a prominent factor to initiate and aggravate the neurodegeneration in Parkinson's disease (PD). Although the involvement of 26S proteasome in proteostasis imbalance has been widely accepted, our knowledge about the regulation of immunoproteasome function and its potential role in α-Syn pathology remains limited. Immunoproteasome abundance and proteolytic activities depend on the finely tuned assembly process, especially β-ring formation mediated by the only well-known chaperone proteasome maturation protein (POMP). Here, we identified that α-Syn overexpression was associated with a reduction in immunoproteasome function, which in turn limited the degradation of polo-like kinase 2 (PLK2), exacerbated α-Syn Ser129 phosphorylation and aggregation, ultimately leading to the neurodegeneration. These effects could be dramatically attenuated by β5i overexpression. Mechanistically, α-Syn suppressed the transcriptional regulation of POMP by nuclear factor erythroid 2-related factor 2 (NRF2), thereby preventing the assembly of immunoproteasome β subunits. Dopaminergic neurons-specific overexpression of NRF2-POMP axis effectively rescued the aggregation of α-Syn and PD-like phenotypes. These findings characterized abnormal immunoproteasome assembly as a key contributor governing α-Syn accumulation and neurodegeneration, which might open up a new perspective for the implication of immunoproteasome in PD and provide approaches of manipulating immunoproteasome assembly for therapeutic purposes.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Transgenic; Parkinson Disease; Phosphorylation; Proteostasis

Paeoniflorin, an active component of Radix Paeoniae Alba, has a neuroprotective effect in Parkinson's animal models. However, its mechanism of action remains to be determined.. In this study, we hypothesized that the neuroprotective effect of paeoniflorin occurs through the α-synuclein/protein kinase C δ subtype (PKC-δ) signaling pathway. We tested our hypothesis in the 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced mouse model of Parkinson's disease. We evaluated the effects of paeoniflorin on the expression levels of signal components of the α-synuclein/PKC-δ pathway, cellular apoptosis and motor performance.. Our results demonstrated that paeoniflorin restored the motor performance impairment caused by MPTP, inhibited apoptosis, and protected the ultrastructure of neurons. Paeoniflorin treatment also resulted in the dose-dependent upregulation of an antiapoptotic protein, B-cell lymphoma-2, at the mRNA and protein levels, similar to the effects of the positive control, selegiline. In contrast, paeoniflorin treatment downregulated the expression of pro-apoptotic proteins BCL2-Associated X2, α-synuclein, and PKC-δ at the mRNA and protein levels, as well as the level of the activated form of nuclear factor kappa B (p-NF-κB p65).. Thus, our results showed that paeoniflorin exerts its neuroprotective effect by regulating the α-synuclein/PKC-δ signaling pathway to reduce neuronal apoptosis.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Annexin A5; Anti-Inflammatory Agents, Non-Steroidal; Antiparkinson Agents; Apoptosis; Disease Models, Animal; Glucosides; Mice; Microscopy, Electron, Transmission; Monoterpenes; Neurotoxins; Parkinsonian Disorders; Protein Kinase C-delta; Rotarod Performance Test; Selegiline; Substantia Nigra

Parkinson's disease (PD) is characterized by the progressive accumulation of neuronal intracellular aggregates largely composed of alpha-Synuclein (αSyn) protein. The process of αSyn aggregation is induced during aging and enhanced by environmental stresses, such as the exposure to pesticides. Paraquat (PQ) is an herbicide which has been widely used in agriculture and associated with PD. PQ is known to cause an increased oxidative stress in exposed individuals but the consequences of such stress on αSyn conformation remains poorly understood. To study αSyn pathogenic modifications in response to PQ, we exposed

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Herbicides; Male; Neurotoxins; Paraquat; Parkinson Disease

Parkinson's disease is a disabling neurodegenerative movement disorder characterized by dopaminergic neuron loss induced by α-synuclein oligomers. There is an urgent need for disease-modifying therapies for Parkinson's disease, but drug discovery is challenged by lack of in vivo models that recapitulate early stages of neurodegeneration. Invertebrate organisms, such as the nematode worm Caenorhabditis elegans, provide in vivo models of human disease processes that can be instrumental for initial pharmacological studies.. To identify early motor impairment of animals expressing α-synuclein in dopaminergic neurons, we first used a custom-built tracking microscope that captures locomotion of single C. elegans with high spatial and temporal resolution. Next, we devised a method for semi-automated and blinded quantification of motor impairment for a population of simultaneously recorded animals with multi-worm tracking and custom image processing. We then used genetic and pharmacological methods to define the features of early motor dysfunction of α-synuclein-expressing C. elegans. Finally, we applied the C. elegans model to a drug repurposing screen by combining it with an artificial intelligence platform and cell culture system to identify small molecules that inhibit α-synuclein oligomers. Screen hits were validated using in vitro and in vivo mammalian models.. We found a previously undescribed motor phenotype in transgenic α-synuclein C. elegans that correlates with mutant or wild-type α-synuclein protein levels and results from dopaminergic neuron dysfunction, but precedes neuronal loss. Together with artificial intelligence-driven in silico and in vitro screening, this C. elegans model identified five compounds that reduced motor dysfunction induced by α-synuclein. Three of these compounds also decreased α-synuclein oligomers in mammalian neurons, including rifabutin which has not been previously investigated for Parkinson's disease. We found that treatment with rifabutin reduced nigrostriatal dopaminergic neurodegeneration due to α-synuclein in a rat model.. We identified a C. elegans locomotor abnormality due to dopaminergic neuron dysfunction that models early α-synuclein-mediated neurodegeneration. Our innovative approach applying this in vivo model to a multi-step drug repurposing screen, with artificial intelligence-driven in silico and in vitro methods, resulted in the discovery of at least one drug that may be repurposed as a disease-modifying therapy for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Artificial Intelligence; Caenorhabditis elegans; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Mammals; Motor Disorders; Rats

Parkinson's disease (PD) is a neurodegenerative disorder characterized by alpha-synuclein (αSyn) aggregation and associated with abnormalities in lipid metabolism. The accumulation of lipids in cytoplasmic organelles called lipid droplets (LDs) was observed in cellular models of PD. To investigate the pathophysiological consequences of interactions between αSyn and proteins that regulate the homeostasis of LDs, we used a transgenic Drosophila model of PD, in which human αSyn is specifically expressed in photoreceptor neurons. We first found that overexpression of the LD-coating proteins Perilipin 1 or 2 (dPlin1/2), which limit the access of lipases to LDs, markedly increased triacylglyclerol (TG) loaded LDs in neurons. However, dPlin-induced-LDs in neurons are independent of lipid anabolic (diacylglycerol acyltransferase 1/midway, fatty acid transport protein/dFatp) and catabolic (brummer TG lipase) enzymes, indicating that alternative mechanisms regulate neuronal LD homeostasis. Interestingly, the accumulation of LDs induced by various LD proteins (dPlin1, dPlin2, CG7900 or KlarsichtLD-BD) was synergistically amplified by the co-expression of αSyn, which localized to LDs in both Drosophila photoreceptor neurons and in human neuroblastoma cells. Finally, the accumulation of LDs increased the resistance of αSyn to proteolytic digestion, a characteristic of αSyn aggregation in human neurons. We propose that αSyn cooperates with LD proteins to inhibit lipolysis and that binding of αSyn to LDs contributes to the pathogenic misfolding and aggregation of αSyn in neurons.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Humans; Lipid Droplets; Lipid Metabolism; Lipolysis; Membrane Transport Proteins; Neuroblastoma; Neurons; Parkinson Disease; Perilipin-2; Protein Aggregation, Pathological; Proteolysis

The cell-to-cell transfer of α-synuclein (α-Syn) greatly contributes to Parkinson's disease (PD) pathogenesis and underlies the spread of α-Syn pathology. During this process, extracellular α-Syn can activate microglia and neuroinflammation, which plays an important role in PD. However, the effect of extracellular α-Syn on microglia autophagy is poorly understood. In the present study, we reported that extracellular α-Syn inhibited the autophagy initiation, as indicated by LC3-II reduction and p62 protein elevation in BV2 and cultured primary microglia. The in vitro findings were verified in microglia-enriched population isolated from α-Syn-overexpressing mice induced by adeno-associated virus (AAV2/9)-encoded wildtype human α-Syn injection into the substantia nigra (SN). Mechanistically, α-Syn led to microglial autophagic impairment through activating toll-like receptor 4 (Tlr4) and its downstream p38 and Akt-mTOR signaling because Tlr4 knockout and inhibition of p38, Akt as well as mTOR prevented α-Syn-induced autophagy inhibition. Moreover, inhibition of Akt reversed the mTOR activation but failed to affect p38 phosphorylation triggered by α-Syn. Functionally, the in vivo evidence showed that lysozyme 2 Cre (Lyz2

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Mice; Neuroinflammatory Diseases; Parkinson Disease

Slow-wave sleep (SWS) modulation in rodent models of Alzheimer’s disease alters extracellular amyloid burden. In Parkinson’s disease (PD), SWS appears to be closely linked with disease symptoms and progression. PD is characterized by damaging intracellular α-synuclein (αSyn) deposition that propagates extracellularly, contributing to disease spread. Intracellular αSyn is sensitive to degradation, whereas extracellular αSyn may be eliminated by glymphatic clearance, a process increased during SWS. Here, we explored whether long-term slow-wave modulation in murine models of PD presenting αSyn aggregation alters pathological protein burden and, thus, might constitute a valuable therapeutic target. Sleep-modulating treatments showed that enhancing slow waves in both VMAT2-deficient and A53T mouse models of PD reduced pathological αSyn accumulation compared to control animals. Nonpharmacological sleep deprivation had the opposite effect in VMAT2-deficient mice, severely increasing the pathological burden. We also found that SWS enhancement was associated with increased recruitment of aquaporin-4 to perivascular sites, suggesting a possible increase of glymphatic function. Furthermore, mass spectrometry data revealed differential and specific up-regulation of functional protein clusters linked to proteostasis upon slow wave–enhancing interventions. Overall, the beneficial effect of SWS enhancement on neuropathological outcome in murine synucleinopathy models mirrors findings in models of Alzheimer. Modulating SWS might constitute an effective strategy for modulating PD pathology in patients.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Disease Models, Animal; Humans; Mice; Parkinson Disease; Sleep, Slow-Wave; Synucleinopathies

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antigens, CD; Cell Line; Disease Models, Animal; Gene Expression Regulation; Gene Knockdown Techniques; Humans; Integrin alpha Chains; Mice; Parkinson Disease; Substantia Nigra; Tyrosine 3-Monooxygenase

Neuroinflammation and mitochondrial impairment play important roles in the neuropathogenesis of Parkinson's disease (PD). The activation of NLRP3 inflammasome and the accumulation of α-synuclein (α-Syn) are strictly correlated to neuroinflammation. Therefore, the regulation of NLRP3 inflammasome activation and α-Syn aggregation might have therapeutic potential. It has been indicated that Dl-3-n-butylphthalide (NBP) produces neuroprotection against some neurological diseases such as ischemic stroke. We here intended to explore whether NBP suppressed NLRP3 inflammasome activation and reduced α-Syn aggregation, thus protecting dopaminergic neurons against neuroinflammation.. In our study, we established a MPTP-induced mouse model and 6-OHDA-induced SH-SY5Y cell model to examine the neuroprotective actions of NBP. We then performed behavioral tests to examine motor dysfunction in MPTP-exposed mice after NBP treatment. Western blotting, immunofluorescence staining, flow cytometry and RT-qPCR were conducted to investigate the expression of NLRP3 inflammasomes, neuroinflammatory cytokines, PARP1, p-α-Syn, and markers of microgliosis and astrogliosis.. The results showed that NBP exerts a neuroprotective effect on experimental PD models.. In summary, NBP rescued dopaminergic neurons by reducing NLRP3 inflammasome activation and ameliorating mitochondrial impairments and increases in p-α-Syn levels. This current study may provide novel neuroprotective mechanisms of NBP as a potential therapeutic agent.

Topics: alpha-Synuclein; Animals; Apoptosis; Benzofurans; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Humans; Inflammasomes; Mice; Mitochondria; Neuroprotective Agents; NLR Family, Pyrin Domain-Containing 3 Protein; Parkinson Disease; Protein Aggregation, Pathological

The aggregation of alpha-synuclein protein (αSyn) is a hallmark of Parkinson's disease (PD). Considerable evidence suggests that PD involves an early aggregation of αSyn in the enteric nervous system (ENS), spreading to the brain. While it has previously been reported that omega-3 polyunsaturated fatty acids (ω-3 PUFA) acts as neuroprotective agents in the brain in murine models of PD, their effect in the ENS remains undefined. Here, we studied the effect of dietary supplementation with docosahexaenoic acid (DHA, an ω-3 PUFA), on the ENS, with a particular focus on enteric dopaminergic (DAergic) neurons. Thy1-αSyn mice, which overexpress human αSyn, were fed ad libitum with a control diet, a low ω-3 PUFA diet or a diet supplemented with microencapsulated DHA and then compared with wild-type littermates. Our data indicate that Thy1-αSyn mice showed a lower density of enteric dopaminergic neurons compared with non-transgenic animals. This decrease was prevented by dietary DHA. Although we found that DHA reduced microgliosis in the striatum, we did not observe any evidence of peripheral inflammation. However, we showed that dietary intake of DHA promoted a build-up of ω-3 PUFA-derived endocannabinoid (eCB)-like mediators in plasma and an increase in glucagon-like peptide-1 (GLP-1) and the redox regulator, Nrf2 in the ENS. Taken together, our results suggest that DHA exerts neuroprotection of enteric DAergic neurons in the Thy1-αSyn mice, possibly through alterations in eCB-like mediators, GLP-1 and Nrf2.

Topics: alpha-Synuclein; Animals; Diet; Dietary Supplements; Disease Models, Animal; Docosahexaenoic Acids; Dopaminergic Neurons; Enteric Nervous System; Mice; Mice, Transgenic; Neuroprotective Agents; Synucleinopathies; Thy-1 Antigens

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopaminergic Neurons; Metformin; Neuroprotective Agents; Parkinson Disease

Parkinson's disease and related disorders are devastating neurodegenerative pathologies. Since α-synuclein was identified as a main component of Lewy bodies and neurites, efforts have been made to clarify the pathogenic mechanisms of α-synuclein's detrimental effects. α-synuclein oligomers are the most harmful species and may recruit and activate glial cells. Inflammation is emerging as a bridge between genetic susceptibility and environmental factors co-fostering Parkinson's disease. However, direct evidence linking inflammation to the harmful activities of α-synuclein oligomers or to the Parkinson's disease behavioural phenotype is lacking.. To clarify whether neuroinflammation influences Parkinson's disease pathogenesis, we developed: (i) a 'double-hit' approach in C57BL/6 naive mice where peripherally administered lipopolysaccharides were followed by intracerebroventricular injection of an inactive oligomer dose; (ii) a transgenic 'double-hit' model where lipopolysaccharides were given to A53T α-synuclein transgenic Parkinson's disease mice.. Lipopolysaccharides induced a long-lasting neuroinflammatory response which facilitated the detrimental cognitive activities of oligomers. LPS-activated microglia and astrocytes responded differently to the oligomers with microglia activating further and acquiring a pro-inflammatory M1 phenotype, while astrocytes atrophied. In the transgenic 'double-hit' A53T mouse model, lipopolysaccharides aggravated cognitive deficits and increased microgliosis. Again, astrocytes responded differently to the double challenge. These findings indicate that peripherally induced neuroinflammation potentiates the α-synuclein oligomer's actions and aggravates cognitive deficits in A53T mice.. The fine management of both peripheral and central inflammation may offer a promising therapeutic approach to prevent or slow down some behavioural aspects in α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Astrocytes; Disease Models, Animal; Inflammation; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Nerve Degeneration; Nervous System Diseases; Parkinson Disease; Substantia Nigra

Understanding Parkinson's disease (PD), in particular in its earliest phases, is important for diagnosis and treatment. However, human brain samples are collected post-mortem, reflecting mainly end-stage disease. Because brain samples of mouse models can be collected at any stage of the disease process, they are useful in investigating PD progression. Here, we compare ventral midbrain transcriptomics profiles from α-synuclein transgenic mice with a progressive, early PD-like striatal neurodegeneration across different ages using pathway, gene set, and network analysis methods. Our study uncovers statistically significant altered genes across ages and between genotypes with known, suspected, or unknown function in PD pathogenesis and key pathways associated with disease progression. Among those are genotype-dependent alterations associated with synaptic plasticity and neurotransmission, as well as mitochondria-related genes and dysregulation of lipid metabolism. Age-dependent changes were among others observed in neuronal and synaptic activity, calcium homeostasis, and membrane receptor signaling pathways, many of which linked to G-protein coupled receptors. Most importantly, most changes occurred before neurodegeneration was detected in this model, which points to a sequence of gene expression events that may be relevant for disease initiation and progression. It is tempting to speculate that molecular changes similar to those changes observed in our model happen in midbrain dopaminergic neurons before they start to degenerate. In other words, we believe we have uncovered molecular changes that accompany the progression from preclinical to early PD.

Topics: Aging; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Female; Gene Expression Profiling; Gene Expression Regulation, Developmental; Gene Ontology; Gene Regulatory Networks; Genotype; Humans; Mice, Transgenic; Nerve Degeneration; Parkinson Disease; Substantia Nigra; Transgenes

There is increasing evidence that EphA1 is involved in the function and development of the central nervous system, especially in neuroinflammation. It has been found to affect the disease progression of Alzheimer's disease (AD) by regulating the neuroinflammatory process. Neuroinflammation has always been regarded as the mechanism of the development of Parkinson's disease (PD) and possible therapeutic targets. Therefore, it is worth studying whether EphA1 has a potential therapeutic value for PD. The purpose of this study is to investigate the effect of EphA1 in mice and PD cell models and its mechanism.In this study, we verified the difference in expression of EphA1 and the effect and mechanism of EphA1 on neuropathological changes through Parkinson's patient samples, Parkinson's mice model, and Parkinson's model prepared from SH-SY5Y cells in vitro.EphA1 was highly expressed in the substantia nigra (SN) region of Parkinson mice and the Parkinson cell model, while the expression of tyrosine hydroxylase (TH) in the SN region of Parkinson mice was significantly reduced. After silenced EphA1 in the SH-SY5Y cell PD model, the expression levels of α-synuclein, inflammatory factors, and microglia-activated chemokine decreased. The co-immunoprecipitation experiment proved that EphA1 overexpression could promote the binding of CXCL12 and CXCR4. However, after silenced EphA1 and CXCL12 at the same time, the above effects brought by silenced EphA1 were suppressed. The same result appeared in mice with PD.EphA1 improves the inflammatory responses and neuropathological changes of the PD model in vivo and in vitro through the CXCL12/CXCR4 signaling pathway. Graphical abstract.

Topics: alpha-Synuclein; Animals; Brain; Cell Line, Tumor; Chemokine CXCL12; Disease Models, Animal; Humans; Inflammation; Male; Mice, Inbred C57BL; Neurotoxins; Parkinson Disease; Receptor, EphA1; Receptors, CXCR4; Signal Transduction

Protective effects of the telomerase protein TERT have been shown in neurons and brain. We previously demonstrated that TERT protein can accumulate in mitochondria of Alzheimer's disease (AD) brains and protect from pathological tau in primary mouse neurons. This prompted us to employ telomerase activators in order to boost telomerase expression in a mouse model of Parkinson's disease (PD) overexpressing human wild type α-synuclein. Our aim was to test whether increased Tert expression levels were able to ameliorate PD symptoms and to activate protein degradation. We found increased Tert expression in brain for both activators which correlated with a substantial improvement of motor functions such as gait and motor coordination while telomere length in the analysed region was not changed. Interestingly, only one activator (TA-65) resulted in a decrease of reactive oxygen species from brain mitochondria. Importantly, we demonstrate that total, phosphorylated and aggregated α-synuclein were significantly decreased in the hippocampus and neocortex of activator-treated mice corresponding to enhanced markers of autophagy suggesting an improved degradation of toxic alpha-synuclein. We conclude that increased Tert expression caused by telomerase activators is associated with decreased α-synuclein protein levels either by activating autophagy or by preventing or delaying impairment of degradation mechanisms during disease progression. This encouraging preclinical data could be translated into novel therapeutic options for neurodegenerative disorders such as PD.

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Mice; Mice, Transgenic; Parkinson Disease; Telomerase

Parkinson's disease psychosis is a prevalent yet underreported and understudied nonmotor manifestation of Parkinson's disease and, arguably, the most debilitating. It is unknown if α-synuclein plays a role in psychosis, and if so, this endophenotype may be crucial for elucidating the neurodegenerative process.. We sought to dissect the underlying neurobiology of novelty-induced hyperactivity, reminiscent of psychosis-like behavior, in human α-synuclein BAC rats.. Herein, we demonstrate a prodromal psychosis-like phenotype, including late-onset sensorimotor gating disruption, striatal hyperdopaminergic signaling, and persistent novelty-induced hyperactivity (up to 18 months), albeit reduced baseline locomotor activity, that is augmented by d-amphetamine and reversed by classical and atypical antipsychotics. MicroRNA-mediated α-synuclein downregulation in the ventral midbrain rescues the hyperactive phenotype and restores striatal dopamine levels. This phenotype is accompanied by an abundance of age-, brain region- and gene dose-dependent aberrant α-synuclein, including hyperphosphorylation, C-terminal truncation, aggregation pathology, and mild nigral neurodegeneration (27%).. Our findings demonstrate a potential role of α-synuclein in Parkinson's disease psychosis and provide evidence of region-specific perturbations prior to neurodegeneration phenoconversion. The reported phenotype coincides with the latest clinical findings that suggest a premotor hyperdopaminergic state may occur, while at the same time, premotor psychotic symptoms are increasingly being recognized. © 2020 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Parkinson Disease; Psychotic Disorders; Rats; Rats, Transgenic; Substantia Nigra

Multiple system atrophy (MSA) is a rare and extremely debilitating progressive neurodegenerative disease characterized by variable combinations of parkinsonism, cerebellar ataxia, dysautonomia, and pyramidal dysfunction. MSA is a unique synucleinopathy, in which alpha synuclein-rich aggregates are present in the cytoplasm of oligodendroglia. The precise origin of the alpha synuclein (aSyn) found in the glial cytoplasmic inclusions (GCIs) as well the mechanisms of neurodegeneration in MSA remain unclear. Despite this fact, cell and animal models of MSA rely on oligodendroglial overexpression of aSyn. In the present study, we utilized a novel oligotrophic AAV, Olig001, to overexpress aSyn specifically in striatal oligodendrocytes of rats and nonhuman primates in an effort to further characterize our novel viral vector-mediated MSA animal models. Using two cohorts of animals with 10-fold differences in Olig001 vector titers, we show a dose-dependent formation of MSA-like pathology in rats. High titer of Olig001-aSyn in these animals were required to produce the formation of pS129+ and proteinase K resistant aSyn-rich GCIs, demyelination, and neurodegeneration. Using this knowledge, we injected high titer Olig001 in the putamen of cynomolgus macaques. After six months, histological analysis showed that oligodendroglial overexpression of aSyn resulted in the formation of hallmark GCIs throughout the putamen, demyelination, a 44% reduction of striatal neurons and a 12% loss of nigral neurons. Furthermore, a robust inflammatory response similar to MSA was produced in Olig001-aSyn NHPs, including microglial activation, astrogliosis, and a robust infiltration of T cells into the CNS. Taken together, oligodendroglial-specific viral vector-mediated overexpression of aSyn in rats and nonhuman primates faithfully reproduces many of the pathological disease hallmarks found in MSA. Future studies utilizing these large animal models of MSA would prove extremely valuable as a pre-clinical platform to test novel therapeutics that are so desperately needed for MSA.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Genetic Vectors; Humans; Macaca fascicularis; Multiple System Atrophy; Neostriatum; Neurons; Oligodendroglia; Putamen; Rats; Stereotaxic Techniques

Abnormal folding, aggregation and spreading of alpha-synuclein (αsyn) is a mechanistic hypothesis for the progressive neuropathology in Parkinson's disease (PD). Spread of αsyn between cells is supported by clinical, neuropathological and experimental evidence. It has been proposed that a pro-inflammatory micro-environment in response to αsyn can promote its aggregation. We have previously shown that allelic differences in the major histocompatibility complex class two transactivator (Mhc2ta) gene, located in the VRA4 locus, alter MHCII expression levels, microglial activation and antigen presentation capacity in rats upon human αsyn over-expression. In addition, Mhc2ta regulated dopaminergic neurodegeneration and the extent of motor impairment. The purpose of this study was to determine whether Mhc2ta regulates αsyn aggregation, propagation and dopaminergic pathology in an αsyn pre-formed fibril (PFF)-seeded in vivo model of PD.. The DA and DA.VRA4 congenic rat strains share background genome but display differential microglial antigen presenting capacity due to different Mhc2ta alleles in the VRA4 locus. PFFs of human αsyn or BSA solution were injected unilaterally to the striatum of DA and DA.VRA4 rats two weeks after ipsilateral administration of recombinant adeno-associated virus (rAAV) vectors carrying human αsyn or GFP to the substantia nigra pars compacta. Behavioural assessment was performed at 2, 5 and 8 weeks while histological evaluation of αsyn pathology, inflammation and neurodegeneration as well as determination of serum cytokine profiles were performed at 8 weeks.. rAAV-mediated expression of human αsyn in nigral dopaminergic neurons combined with striatal PFF administration induced enhanced αsyn pathology in DA.VRA4 compared to DA rats. Mhc2ta thus significantly regulated the seeding, propagation and toxicity of αsyn in vivo. This was reflected in terms of wider extent and anatomical distribution of αsyn inclusions, ranging from striatum to the forebrain, midbrain, hindbrain and cerebellum in DA.VRA4. Compared to DA rats, DA.VRA4 also displayed enhanced motor impairment and dopaminergic neurodegeneration as well as higher levels of the proinflammatory cytokines IL-2 and TNFα in serum.. We conclude that the key regulator of MHCII expression, Mhc2ta, modulates neuroinflammation, αsyn-seeded Lewy-like pathology, dopaminergic neurodegeneration and motor impairment. This makes Mhc2ta and microglial antigen presentation promising therapeutic targets for reducing the progressive neuropathology and clinical manifestations in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Nuclear Proteins; Parkinson Disease; Rats; Substantia Nigra; Trans-Activators

The formation of α-synuclein aggregates is a major pathological hallmark of Parkinson's disease. Copper promotes α-synuclein aggregation and toxicity in vitro. The level of copper and copper transporter 1, which is the only known high-affinity copper importer in the brain, decreases in the substantia nigra of Parkinson's disease patients. However, the relationship between copper, copper transporter 1 and α-synuclein pathology remains elusive. Here, we aim to decipher the molecular mechanisms of copper and copper transporter 1 underlying Parkinson's disease pathology. We employed yeast and mammalian cell models expressing human α-synuclein, where exogenous copper accelerated intracellular α-synuclein inclusions and silencing copper transporter 1 reduced α-synuclein aggregates in vitro, suggesting that copper transporter 1 might inhibit α-synuclein pathology. To study our hypothesis in vivo, we generated a new transgenic mouse model with copper transporter 1 conditional knocked-out specifically in dopaminergic neuron. Meanwhile, we unilaterally injected adeno-associated viral human-α-synuclein into the substantia nigra of these mice. Importantly, we found that copper transporter 1 deficiency significantly reduced S129-phosphorylation of α-synuclein, prevented dopaminergic neuronal loss, and alleviated motor dysfunction caused by α-synuclein overexpression in vivo. Overall, our data indicated that inhibition of copper transporter 1 alleviated α-synuclein mediated pathologies and provided a novel therapeutic strategy for Parkinson's disease and other synucleinopathies.

Topics: alpha-Synuclein; Animals; Copper Transporter 1; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Parkinson Disease; Synucleinopathies

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Mice; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is the second most common neurodegenerative disease. Pathologically, PD is characterized by the formation of Lewy bodies (LBs) in the brain, which mainly comprises phosphorylated and aggregated α-synuclein (α-syn). The aberrant aggregation of α-syn is believed to play a key role in the pathogenesis of PD. While α-syn expression can be reduced by antisense oligonucleotides (ASOs), the challenge to deliver ASOs safely and effectively into the neurons remains unresolved. Here, we developed a safe and highly effective ASO delivery method by using exosomes. We first identified the ASO sequence that selectively reduced α-syn expression: ASO4. Exosome-mediated delivery of ASO4 (exo-ASO4) showed high cellular uptake and low toxicity in primary neuronal cultures. Exo-ASO4 also significantly attenuated α-syn aggregation induced by pre-formed α-syn fibrils in vitro. Exo-ASO4 intracerebroventricular injection into the brains of α-syn A53T mice, a transgenic model of PD, significantly decreased the expression of α-syn and attenuated its aggregation. Furthermore, exo-ASO4 ameliorated the degeneration of dopaminergic neurons in these mice. Finally, the α-syn A53T mice showed significantly improved locomotor functions after exo-ASO4 injection. Overall, this study demonstrates that exosome-mediated ASO4 delivery may be an effective treatment option for PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Drug Carriers; Exosomes; Humans; Injections, Intraventricular; Locomotion; Mice; Mice, Transgenic; Oligonucleotides, Antisense; Parkinson Disease

Neuroinflammation is increasingly recognized as an important feature in the pathogenesis of Parkinson's disease (PD). However, it remains unclear whether neuroinflammation contributes to nigral degeneration in PD or is merely a secondary marker of neurodegeneration. We aimed to investigate the temporal relationship between synucleopathy, neuroinflammation and nigrostriatal degeneration in a mouse model of PD. Mice received unilateral intrastriatal injection of alpha-synuclein pre-formed fibrils, alpha-synuclein monomer or vehicle and were sacrificed at 15, 30 and 90 days post-injection. Intrastriatal inoculation of alpha-synuclein fibrils led to significant alpha-synuclein aggregation in the substantia nigra peaking at 30 days after injection while the significant increase in Iba-1 cells, GFAP cells and IL-1β expression peaked earlier at 15 days. At 90 days, the striatal dopaminergic denervation was associated with astroglial activation. Alpha-synuclein monomer did not result in long-term glia activation or increase in inflammatory markers. The spread of alpha-synuclein aggregates into the cortex was not associated with any changes to neuroinflammatory markers. Our results demonstrate that in the substantia nigra glial activation is an early event that precedes alpha-synuclein inclusion formation, suggesting neuroinflammation could play an important early role in the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Mice; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is a neurodegenerative disease with complicated pathogenesis. A novel bibenzyl compound 2-[4-hydroxy-3-(4-hydroxyphenyl)benzyl]-4-(4-hydroxyphenyl)phenol (20C) has been shown to have some neuroprotective effects, and its mechanism still needs further research. In this study, we used a 6-hydroxydopamine (6-OHDA)-induced PD rat model to evaluate the protective effect of 20C. Our study found that 20C could improve behavioral defects in 6-OHDA-lesion rats, decrease neuroinflammation and protect their DA neurons. It could inhibit the activity of inducible nitric oxide synthase (iNOS) induced by 6-OHDA, and lead to a decrease in the expression of nitrated-α-synuclein. When exposed to AMT-an inhibitor of iNOS, the nitrated-α-synuclein in PC12 decreased, and 20C demonstrated the same function on nitrated-α-synuclein as AMT. Besides, we also found that nitrated-α-synuclein was displayed in microglia. And 20C could decrease the expression of antigen-presenting molecule major histocompatibility complex I (MHC I) in dopamine (DA) neurons and MHC II in microglia induced by 6-OHDA. So, these imply that nitrated-α-synuclein might act as an endogenous antigen activating adaptive immunity, and the neuroprotection of 20C might be associated with inhibiting the activity of iNOS, decreasing the expression of the antigen molecule nitrated-α-synuclein and the antigen presenting molecule MHC. Our results indicated that inhibiting iNOS might be an effective strategy to protect neurons from oxidative stress.

Topics: alpha-Synuclein; Animals; Antioxidants; Bibenzyls; Brain; Cytokines; Disease Models, Animal; Dopaminergic Neurons; Endocytosis; Enzyme Inhibitors; Inflammation Mediators; Male; Microglia; Neuroprotective Agents; Nitric Oxide Synthase Type II; Oxidative Stress; Oxidopamine; Parkinsonian Disorders; PC12 Cells; Rats; Rats, Sprague-Dawley; Signal Transduction

Parkinson's disease (PD) develops due to oxidative stress, mitochondrial aberrations, posttranslational modification, and α-Synuclein (α-Syn) aggregation. The α-synucleinopathy is attributed to phosphorylation and aggregation of α-Syn. A strategy to degrade or reduce phosphorylated protein paves the way to develop PD therapy. Hence, the neuroprotective efficiency of PP2A (Protein phosphatase 2) activator FTY720, loaded chitosan nanoformulation has been evaluated in vitro and ex vivo experimental PD models. Bio-compatible chitosan-based nanocarriers have been utilized to enhance the bio-availability and neuroprotective effect of FTY720. The neuroprotective effect of characterized nanoformulation was determined by the downregulation of PD hallmark phospho-serine 129 (pSer129) α-Syn, with anti-oxidative and anti-inflammatory potentials. The neuroprotective mechanism uncovered novel physical interaction of PP2A and polycomb group of protein Enhancer of zeste homolog 2 to mediate ubiquitination and degradation of agglomerated pSer129 α-Syn. Indeed, this study establishes the neuroprotective potential of chitosan based FTY720 nanoformulations by PP2A mediated epigenetic regulation for PD prevention.

Topics: alpha-Synuclein; Animals; Biological Availability; Cell Line, Tumor; Chitosan; Disease Models, Animal; Drug Carriers; Enhancer of Zeste Homolog 2 Protein; Epigenesis, Genetic; Fingolimod Hydrochloride; Humans; Mice; Mice, Inbred BALB C; Neurons; Neuroprotective Agents; Parkinson Disease; Phosphorylation; Protein Aggregates; Protein Phosphatase 2; Proteolysis; Signal Transduction; Sphingosine 1 Phosphate Receptor Modulators; Ubiquitination

Misfolded α-synuclein is a major component of Lewy bodies, which are a hallmark of Parkinson's disease (PD). A large body of evidence shows that α-synuclein can aggregate into amyloid fibrils, but the relationship between α-synuclein self-assembly and Lewy body formation remains unclear. Here, we show, both in vitro and in a Caenorhabditis elegans model of PD, that α-synuclein undergoes liquid‒liquid phase separation by forming a liquid droplet state, which converts into an amyloid-rich hydrogel with Lewy-body-like properties. This maturation process towards the amyloid state is delayed in the presence of model synaptic vesicles in vitro. Taken together, these results suggest that the formation of Lewy bodies may be linked to the arrested maturation of α-synuclein condensates in the presence of lipids and other cellular components.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Humans; Lewy Bodies; Parkinson Disease

Alpha-synuclein (αsyn) is the key component of proteinaceous aggregates termed Lewy Bodies that pathologically define a group of disorders known as synucleinopathies, including Parkinson's Disease (PD) and Dementia with Lewy Bodies. αSyn is hypothesized to misfold and spread throughout the brain in a prion-like fashion. Transmission of αsyn necessitates the release of misfolded αsyn from one cell and the uptake of that αsyn by another, in which it can template the misfolding of endogenous αsyn upon cell internalization. 14-3-3 proteins are a family of highly expressed brain proteins that are neuroprotective in multiple PD models. We have previously shown that 14-3-3θ acts as a chaperone to reduce αsyn aggregation, cell-to-cell transmission, and neurotoxicity in the in vitro pre-formed fibril (PFF) model. In this study, we expanded our studies to test the impact of 14-3-3s on αsyn toxicity in the in vivo αsyn PFF model. We used both transgenic expression models and adenovirus associated virus (AAV)-mediated expression to examine whether 14-3-3 manipulation impacts behavioral deficits, αsyn aggregation, and neuronal counts in the PFF model. 14-3-3θ transgene overexpression in cortical and amygdala regions rescued social dominance deficits induced by PFFs at 6 months post injection, whereas 14-3-3 inhibition by transgene expression of the competitive 14-3-3 peptide inhibitor difopein in the cortex and amygdala accelerated social dominance deficits. The behavioral rescue by 14-3-3θ overexpression was associated with delayed αsyn aggregation induced by PFFs in these brain regions. Conversely, 14-3-3 inhibition by difopein in the cortex and amygdala accelerated αsyn aggregation and reduction in NECAB1-positive neuron counts induced by PFFs. 14-3-3θ overexpression by AAV in the substantia nigra (SN) also delayed αsyn aggregation in the SN and partially rescued PFF-induced reduction in tyrosine hydroxylase (TH)-positive dopaminergic cells in the SN. 14-3-3 inhibition in the SN accelerated nigral αsyn aggregation and enhanced PFF-induced reduction in TH-positive dopaminergic cells. These data indicate a neuroprotective role for 14-3-3θ against αsyn toxicity in vivo.

Topics: 14-3-3 Proteins; alpha-Synuclein; Amygdala; Animals; Behavior, Animal; Cerebral Cortex; Disease Models, Animal; Dopaminergic Neurons; Gene Knock-In Techniques; Mice; Mice, Transgenic; Neurons; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; Proteins; Social Dominance; Substantia Nigra

Lysosomal dysfunction may be an important factor in the pathogenesis of neurodegenerative disorders such as Parkinson's disease (PD). Heterozygous mutations in the gene encoding the lysosomal enzyme glucocerebrosidase (GBA1) have been found in PD patients, and some but not all mutations in other lysosomal enzyme genes, for example, NPC1 and MCOLN1 have been associated with PD. We have examined the behaviour and brain structure of mice carrying a D31N mutation in the sulphamidase (Sgsh) gene which encodes a lysosomal sulphatase. Female heterozygotes and wildtype mice aged 12-, 15-, 18- and 21-months of age underwent motor phenotyping and the brain was comprehensively evaluated for disease-associated lesions. Heterozygous mice exhibited impaired performance in the negative geotaxis test when compared with wildtype mice. Whilst the brain of Sgsh heterozygotes aged up to 21-months did not exhibit any of the gross features of PD, Alzheimer's disease or the neurodegenerative lysosomal storage disorders, for example, loss of striatal dopamine, reduced GBA activity, α-synuclein-positive inclusions, perturbation of lipid synthesis, or cerebellar Purkinje cell drop-out, we noted discrete structural aberrations in the dendritic tree of cortical pyramidal neurons in 21-month old animals. The overt disease lesions and resultant phenotypic changes previously described in individuals with heterozygous mutations in lysosomal enzyme genes such as glucocerebrosidase may be enzyme dependent. By better understanding why deficiency in, or mutant forms of some but not all lysosomal proteins leads to heightened risk or earlier onset of classical neurodegenerative disorders, novel disease-causing mechanisms may be identified.

Topics: Age Factors; alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Dopamine; Female; Glucosylceramidase; Heterozygote; Hydrolases; Mice; Mutation; Parkinson Disease; Risk Factors

The pathological hallmark of Parkinson's disease (PD) is the formation of Lewy bodies containing aggregated alpha-synuclein (α-syn). Although PD is associated with these distinct histological changes, other pathological features such as microvascular alterations have been linked to neurodegeneration. These changes need to be investigated as they create a hostile brain microenvironment and may contribute to the development and progression of the disease. We use a human α-syn overexpression mouse model that recapitulates some of the pathological features of PD in terms of progressive aggregation of human α-syn, impaired striatal dopamine fiber density, and an age-dependent motor deficit consistent with an impaired dopamine release. We demonstrate for the first time in this model a compromised blood-brain barrier integrity and dynamic changes in vessel morphology from angiogenesis at earlier stages to vascular regression at later stages. The vascular alterations are accompanied by a pathological activation of pericytes already at an early stage without changing overall pericyte density. Our data support and further extend the occurrence of vascular pathology as an important pathophysiological aspect in PD. The model used provides a powerful tool to investigate disease-modifying factors in PD in a temporal sequence that might guide the development of new treatments.

Topics: Aging; alpha-Synuclein; Animals; Blood Vessels; Blood-Brain Barrier; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Endothelial Cells; Humans; Male; Mice; Mice, Transgenic; Motor Activity; Neurons; Parkinson Disease; Pericytes; Recombinant Fusion Proteins; Substantia Nigra; Tyrosine 3-Monooxygenase

The accumulation of α-synuclein amyloid fibrils in the brain is linked to Parkinson's disease and other synucleinopathies. The intermediate species in the early aggregation phase of α-synuclein are involved in the emergence of amyloid toxicity and considered to be the most neurotoxic. The N-terminal region flanking the non-amyloid-β component domain of α-synuclein has been implicated in modulating its aggregation. Herein, we report the development of a SUMO1-derived peptide inhibitor (SUMO1(15-55)), which targets two SUMO-interacting motifs (SIMs) within this aggregation-regulating region and suppresses α-synuclein aggregation. Molecular modeling, site-directed mutagenesis, and binding studies are used to elucidate the mode of interaction, namely, via the binding of either of the two SIM sequences on α-synuclein to a putative hydrophobic binding groove on SUMO1(15-55). Subsequent studies show that SUMO1(15-55) also reduces α-synuclein-induced cytotoxicity in cell-based and Drosophila disease models.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drosophila; Drug Discovery; Humans; Parkinson Disease; Peptides; Protein Aggregates; Protein Aggregation, Pathological; Protein Interaction Maps; SUMO-1 Protein

Aside from the classical motor symptoms, Parkinson's disease also has various non-classical symptoms. Interestingly, orexin neurons, involved in the regulation of exploratory locomotion, spontaneous physical activity, and energy expenditure, are affected in Parkinson's. In this study, we hypothesized that Parkinson's-disease-associated pathology affects orexin neurons and therefore impairs functions they regulate. To test this, we used a transgenic animal model of Parkinson's, the A53T mouse. We measured body composition, exploratory locomotion, spontaneous physical activity, and energy expenditure. Further, we assessed alpha-synuclein accumulation, inflammation, and astrogliosis. Finally, we hypothesized that chemogenetic inhibition of orexin neurons would ameliorate observed impairments in the A53T mice. We showed that aging in A53T mice was accompanied by reductions in fat mass and increases in exploratory locomotion, spontaneous physical activity, and energy expenditure. We detected the presence of alpha-synuclein accumulations in orexin neurons, increased astrogliosis, and microglial activation. Moreover, loss of inhibitory pre-synaptic terminals and a reduced number of orexin cells were observed in A53T mice. As hypothesized, this chemogenetic intervention mitigated the behavioral disturbances induced by Parkinson's disease pathology. This study implicates the involvement of orexin in early Parkinson's-disease-associated impairment of hypothalamic-regulated physiological functions and highlights the importance of orexin neurons in Parkinson's disease symptomology.

Topics: alpha-Synuclein; Animals; Body Composition; Disease Models, Animal; Energy Metabolism; Gliosis; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Neurons; Orexins; Parkinson Disease

Velvet antler is the traditional tonic food or medicine used in East Asia for treating aging-related diseases. Herein, we try to dissect the pharmacology of methanol extracts (MEs) of velvet antler on Parkinson's disease (PD).

Topics: alpha-Synuclein; Animals; Antlers; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Inflammation; Male; Methanol; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Signal Transduction; Tissue Extracts

Alteration to endoplasmic reticulum (ER) proteostasis is observed in a variety of neurodegenerative diseases associated with abnormal protein aggregation. Activation of the unfolded protein response (UPR) enables an adaptive reaction to recover ER proteostasis and cell function. The UPR is initiated by specialized stress sensors that engage gene expression programs through the concerted action of the transcription factors ATF4, ATF6f, and XBP1s. Although UPR signaling is generally studied as unique linear signaling branches, correlative evidence suggests that ATF6f and XBP1s may physically interact to regulate a subset of UPR target genes. In this study, we designed an ATF6f/XBP1s fusion protein termed UPRplus that behaves as a heterodimer in terms of its selective transcriptional activity. Cell-based studies demonstrated that UPRplus has a stronger effect in reducing the abnormal aggregation of mutant huntingtin and α-synuclein when compared to XBP1s or ATF6 alone. We developed a gene transfer approach to deliver UPRplus into the brain using adeno-associated viruses (AAVs) and demonstrated potent neuroprotection in vivo in preclinical models of Parkinson's disease and Huntington's disease. These results support the concept in which directing UPR-mediated gene expression toward specific adaptive programs may serve as a possible strategy to optimize the beneficial effects of the pathway in different disease conditions.

Topics: Activating Transcription Factor 6; alpha-Synuclein; Animals; Disease Models, Animal; HEK293 Cells; Humans; Huntingtin Protein; Male; Mice; Multiprotein Complexes; Mutation; Neurodegenerative Diseases; Unfolded Protein Response; X-Box Binding Protein 1

Patients with Parkinson's disease (PD) show motor symptoms as well as various non-motor symptoms. Postmortem studies of PD have suggested that initial alpha-synuclein (α-Syn) pathology develops independently in the olfactory bulb and lower brainstem, spreading from there stereotypically. However, it remains unclear how these two pathological pathways contribute to the clinicopathological progression of PD.. The objective of this study was to examine the clinicopathological contribution of α-Syn spread from the olfactory bulb.. We conducted pathological and behavioral analyses of human α-Syn bacterial artificial chromosome transgenic mice injected with α-Syn preformed fibrils into the bilateral olfactory bulb up to 10 months postinjection.. α-Syn preformed fibril injections induced more widespread α-Syn pathology in the transgenic mice than that in wild-type mice. Severe α-Syn pathology in the transgenic mice injected with α-Syn preformed fibrils was initially observed along the olfactory pathway and later in the brain regions that are included in the limbic system and have connections with it. The α-Syn pathology was accompanied by regional atrophy, neuron loss, reactive astrogliosis, and microglial activation, which were remarkable in the hippocampus. Behavioral analyses revealed hyposmia, followed by anxiety-like behavior and memory impairment, but not motor dysfunction, depression-like behavior, or circadian rhythm disturbance.. Our data suggest that α-Syn spread from the olfactory bulb mainly affects the olfactory pathway and limbic system as well as its related regions, leading to the development of hyposmia, anxiety, and memory loss in PD. © 2021 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Anosmia; Anxiety; Disease Models, Animal; Humans; Memory Disorders; Mice; Mice, Transgenic; Olfactory Bulb

Vesicular trafficking defects, particularly those in the autophagolysosomal system, have been strongly implicated in the pathogenesis of Parkinson's disease and related α-synucleinopathies. However, mechanisms mediating dysfunction of membrane trafficking remain incompletely understood. Using a Drosophila model of α-synuclein neurotoxicity with widespread and robust pathology, we find that human α-synuclein expression impairs autophagic flux in aging adult neurons. Genetic destabilization of the actin cytoskeleton rescues F-actin accumulation, promotes autophagosome clearance, normalizes the autophagolysosomal system, and rescues neurotoxicity in α-synuclein transgenic animals through an Arp2/3 dependent mechanism. Similarly, mitophagosomes accumulate in human α-synuclein-expressing neurons, and reversal of excessive actin stabilization promotes both clearance of these abnormal mitochondria-containing organelles and rescue of mitochondrial dysfunction. These results suggest that Arp2/3 dependent actin cytoskeleton stabilization mediates autophagic and mitophagic dysfunction and implicate failure of autophagosome maturation as a pathological mechanism in Parkinson's disease and related α-synucleinopathies.

Topics: Actin Cytoskeleton; Actin-Related Protein 2-3 Complex; Actins; Aging; alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagosomes; Autophagy; Disease Models, Animal; Drosophila melanogaster; Humans; Microscopy, Electron, Transmission; Mitochondria; Neurons; Parkinson Disease

Abnormal aggregation of the α-synuclein protein is a key molecular feature of Parkinson's disease and other neurodegenerative diseases. The precise mechanisms that trigger α-synuclein aggregation are unclear, and it is not known what role aggregation plays in disease pathogenesis. Here we use an in vivo zebrafish model to express several different forms of human α-synuclein and measure its aggregation in presynaptic terminals. We show that human α-synuclein tagged with GFP can be expressed in zebrafish neurons, localizing normally to presynaptic terminals and undergoing phosphorylation at serine-129, as in mammalian neurons. The visual advantages of the zebrafish system allow for dynamic in vivo imaging to study α-synuclein, including the use of fluorescence recovery after photobleaching (FRAP) techniques to probe protein mobility. These experiments reveal three distinct terminal pools of α-synuclein with varying mobility, likely representing different subpopulations of aggregated and non-aggregated protein. Human α-synuclein is phosphorylated by an endogenous zebrafish Polo-like kinase activity, and there is a heterogeneous population of neurons containing either very little or extensive phosphorylation throughout the axonal arbor. Both pharmacological and genetic manipulations of serine-129 show that phosphorylation of α-synuclein at this site does not significantly affect its mobility. This suggests that serine-129 phosphorylation alone does not promote α-synuclein aggregation. Together our results show that human α-synuclein can be expressed and measured quantitatively in zebrafish, and that disease-relevant post-translational modifications occur within neurons. The zebrafish model provides a powerful in vivo system for measuring and manipulating α-synuclein function and aggregation, and for developing new treatments for neurodegenerative disease.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Humans; Parkinson Disease; Phosphorylation; Presynaptic Terminals; Protein Aggregation, Pathological; Serine; Zebrafish

Parkinson's disease is a neurodegenerative disorder characterized by accumulation of misfolded α-synuclein within the central nervous system (CNS). Retinal manifestations have been widely described as a prodromal symptom; however, we have a limited understanding of the retinal pathology associated with Parkinson's disease. The strong similarities between the retina and the brain and the accessibility of the retina has potentiated studies to investigate retinal pathology in an effort to identify biomarkers for early detection, as well as for monitoring the progression of disease and efficacy of therapies as they become available. Here, we discuss a study conducted using a transgenic mouse model of Parkinson's disease (TgM83, expressing human α-synuclein containing the familial PD-associated A53T mutation) to demonstrate the effect of the A53T α-synuclein mutation on the retina. Additionally, we show that "seeding" with brain homogenates from clinically ill TgM83 mice accelerates the accumulation of retinal α-synuclein. The work described in this chapter provides insight into retinal changes associated with Parkinson's disease and identifies retinal indicators of Parkinson's disease pathogenesis that could serve as potential biomarkers for early detection.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Parkinson Disease; Retina

Convincing evidence supports the premise that reducing α-synuclein levels may be an effective therapy for Parkinson's disease (PD); however, there has been lack of a clinically applicable α-synuclein reducing therapeutic strategy. This study was undertaken to develop a blood-brain barrier and plasma membrane-permeable α-synuclein knockdown peptide, Tat-βsyn-degron, that may have therapeutic potential. The peptide effectively reduced the level of α-synuclein via proteasomal degradation both in cell cultures and in animals. Tat-βsyn-degron decreased α-synuclein aggregates and microglial activation in an α-synuclein pre-formed fibril model of spreading synucleinopathy in transgenic mice overexpressing human A53T α-synuclein. Moreover, Tat-βsyn-degron reduced α-synuclein levels and significantly decreased the parkinsonian toxin-induced neuronal damage and motor impairment in a mouse toxicity model of PD. These results show the promising efficacy of Tat-βsyn-degron in two different animal models of PD and suggest its potential use as an effective PD therapeutic that directly targets the disease-causing process.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Behavior, Animal; Brain; Disease Models, Animal; Down-Regulation; HEK293 Cells; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; MPTP Poisoning; Mutation; Neurons; Parkinson Disease; Peptides; Proteasome Endopeptidase Complex; Proteolysis; Rats, Sprague-Dawley

Pain is a common non-motor symptom of Parkinson's disease (PD), with current limited knowledge of its pathophysiology. Here, we show that peripheral inoculation of mouse alpha-synuclein (α-Syn) pre-formed fibrils, in a transgenic mouse model of PD, elicited retrograde trans-synaptic spreading of α-Syn pathology (pSer129) across sensory neurons and dorsal nerve roots, reaching central pain processing regions, including the spinal dorsal horn and the projections of the anterolateral system in the central nervous system (CNS). Pathological peripheral to CNS propagation of α-Syn aggregates along interconnected neuronal populations within sensory afferents, was concomitant with impaired nociceptive response, reflected by mechanical allodynia, reduced nerve conduction velocities (sensory and motor) and degeneration of small- and medium-sized myelinated fibers. Our findings show a link between the transneuronal propagation of α-Syn pathology with sensory neuron dysfunction and neuropathic impairment, suggesting promising avenues of investigation into the mechanisms underlying pain in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Mice; Mice, Transgenic; Microscopy, Electron, Transmission; Neuralgia; Parkinson Disease; Retrograde Degeneration; Sensory Receptor Cells; Synaptic Transmission; Synucleinopathies

The pathogenesis of Parkinson's disease involves fibrillization and deposition of alpha-synuclein (α-syn) into Lewy bodies. Accumulating evidence suggests that α-syn oligomers are particularly neurotoxic. Transgenic (tg) mice overexpressing wild-type human α-syn under the Thy-1 promoter (L61) reproduce many Parkinson's disease features, but the pathogenetic relevance of α-syn oligomers in this mouse model has not been studied in detail. Here, we report an age progressive increase of α-syn oligomers in the brain of L61 tg mice. Interestingly, more profound motor symptoms were observed in animals with higher levels of membrane-bound oligomers. As this tg model is X-linked, we also performed subset analyses, indicating that both sexes display a similar age-related increase in α-syn oligomers. However, compared with females, males featured increased brain levels of oligomers from an earlier age, in addition to a more severe behavioral phenotype with hyperactivity and thigmotaxis in the open field test. Taken together, our data indicate that α-syn oligomers are central to the development of brain pathology and behavioral deficits in the L61 tg α-syn mouse model.

Topics: Aging; alpha-Synuclein; Animals; Disease Models, Animal; Female; Gene Expression; Lewy Bodies; Male; Mice, Transgenic; Parkinson Disease; Promoter Regions, Genetic; Thy-1 Antigens

Parkinson's disease (PD) is a prevalent neurodegenerative disease with no approved disease-modifying therapies. Multiplications, mutations, and single nucleotide polymorphisms in the SNCA gene, encoding α-synuclein (aSyn) protein, either cause or increase risk for PD. Intracellular accumulations of aSyn are pathological hallmarks of PD. Taken together, reduction of aSyn production may provide a disease-modifying therapy for PD. We show that antisense oligonucleotides (ASOs) reduce production of aSyn in rodent preformed fibril (PFF) models of PD. Reduced aSyn production leads to prevention and removal of established aSyn pathology and prevents dopaminergic cell dysfunction. In addition, we address the translational potential of the approach through characterization of human SNCA-targeting ASOs that efficiently suppress the human SNCA transcript in vivo. We demonstrate broad activity and distribution of the human SNCA ASOs throughout the nonhuman primate brain and a corresponding decrease in aSyn cerebral spinal fluid (CSF) levels. Taken together, these data suggest that, by inhibiting production of aSyn, it may be possible to reverse established pathology; thus, these data support the development of SNCA ASOs as a potential disease-modifying therapy for PD and related synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Cell Culture Techniques; Cerebrospinal Fluid; Disease Models, Animal; Dopaminergic Neurons; Female; Humans; Macaca fascicularis; Male; Mice; Oligonucleotides, Antisense; Parkinson Disease; Rats, Sprague-Dawley; RNA, Messenger

Peripheral biomarkers indicative of brain pathology are critically needed for early detection of Parkinson's disease (PD). In this study, using NanoString and digital PCR technologies, we began by screening for alterations in genes associated with PD or atypical Parkinsonism in erythrocytes of PD patients, in which PD-related changes have been reported, and which contain ~ 99% of blood α-synuclein. Erythrocytic CHCHD2 mRNA was significantly reduced even at the early stages of the disease. A significant reduction in protein and/or mRNA expression of CHCHD2 was confirmed in PD brains collected at autopsy as well as in the brains of a PD animal model overexpressing α-synuclein, in addition to seeing a reduction of CHCHD2 in erythrocytes of the same animals. Overexpression of α-synuclein in cellular models of PD also resulted in reduced CHCHD2, via mechanisms likely involving altered subcellular localization of p300 histone acetyltransferase. Finally, the utility of reduced CHCHD2 mRNA as a biomarker for detecting PD, including early-stage PD, was validated in a larger cohort of 205 PD patients and 135 normal controls, with a receiver operating characteristic analysis demonstrating > 80% sensitivity and specificity.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Autopsy; Biomarkers; Brain; Cohort Studies; Disease Models, Animal; DNA-Binding Proteins; Erythrocytes; Female; Humans; Male; Mice; Mice, Transgenic; Middle Aged; Mitochondria; Mutation; p300-CBP Transcription Factors; Parkinson Disease; RNA, Messenger; Transcription Factors

α-Synuclein, a key pathological component of Parkinson's disease, has been implicated in the activation of the innate and adaptive immune system. This immune activation includes microgliosis, increased inflammatory cytokines, and the infiltration of T cells into the CNS. More recently, peripherally circulating CD4 and CD8 T cells derived from individuals with Parkinson's disease have been shown to produce Th1/Th2 cytokines in response to α-synuclein, suggesting there may be a chronic memory T cell response present in Parkinson's disease. To understand the potential effects of these α-syn associated T cell responses we used an α-synuclein overexpression mouse model, T cell-deficient mice, and a combination of immunohistochemistry and flow cytometry. In this study, we found that α-synuclein overexpression in the midbrain of mice leads to the upregulation of the major histocompatibility complex II (MHCII) protein on CNS myeloid cells as well as the infiltration of IFNγ producing CD4 and CD8 T cells into the CNS. Interestingly, genetic deletion of TCRβ or CD4, as well as the use of the immunosuppressive drug fingolimod, were able to reduce the CNS myeloid MHCII response to α-synuclein. Furthermore, we observed that CD4-deficient mice were protected from the dopaminergic cell loss observed due to α-syn overexpression. These results suggest that T cell responses associated with α-synuclein pathology may be damaging to key areas of the CNS in Parkinson's disease and that targeting these T cell responses could be an avenue for disease modifying treatments.

Topics: alpha-Synuclein; Animals; CD4-Positive T-Lymphocytes; Disease Models, Animal; Encephalitis; Female; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Parkinson Disease

Aggregation and deposition of α-synuclein (α-syn) in Lewy bodies within dopamine neurons of substantia nigra (SN) is the pathological hallmark of Parkinson's disease (PD). These toxic α-syn aggregates are believed to propagate from neuron-to-neuron and spread the α-syn pathology throughout the brain beyond dopamine neurons in a prion-like manner. Targeting propagation of such α-syn aggregates is of high interest but requires identifying pathways involving in this process. Evidence from previous Alzheimer's disease reports suggests that EGFR may be involved in the prion-like propagation and seeding of amyloid-β. We show here that EGFR regulates the uptake of exogenous α-syn-PFFs and the levels of endogenous α-syn in cell cultures and a mouse model of α-syn propagation, respectively. Thus, we tested the therapeutic potentials of AZD3759, a highly selective BBB-penetrating EGFR inhibitor, in a preclinical mouse model of α-syn propagation. AZD3759 decreases activated EGFR levels in the brain and reduces phosphorylated α-synuclein (pSyn) pathology in brain sections, including striatum and SN. As AZD3759 is already in the clinic, this paper's results suggest a possible repositioning of AZD3759 as a disease-modifying approach for PD.

Topics: alpha-Synuclein; Animals; Blood-Brain Barrier; Brain; Cells, Cultured; Disease Models, Animal; Dose-Response Relationship, Drug; ErbB Receptors; Humans; Male; Mice; Mice, Inbred C57BL; Piperazines; Quinazolines; RNA, Small Interfering; Synucleinopathies

In many scientific disputes, research evidence may support one side or the other of a working hypothesis, and even in case of largely coherent hypotheses, arguments may be in favor of discrepant points of view. In the case of α-synuclein pathology and specific mechanisms of disease progression, various animal and cellular models have been established to pinpoint the physiological and pathological mechanisms. In the present 'Editorial controversy', two well-reputed researchers, Hilal Lashuel and Tiago F. Outeiro, discuss-with view to findings from their own and others' groups in the context of current status of knowledge-the question of how well models on α-synuclein pathology can reflect actual pathomechanisms, and derive recommendations for future research from it that shall help advance our understanding not only of α-synuclein-related pathologies and its role in the formation of Lewy bodies in particular, but of cellular or animal models in general.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Protein Aggregation, Pathological; Synucleinopathies

The repurposing of drugs developed to treat type 2 diabetes for the treatment of Parkinson's disease (PD) was encouraged by the beneficial effect exerted by the glucagon-like peptide 1 (GLP-1) analogue exenatide in a phase 2 clinical trial. The effects of GLP-1 analogues have been investigated extensively using rodent toxin models of PD. However, many of the toxin-based models used lack robust α-synuclein (α-syn) pathology, akin to the Lewy bodies and neurites seen in PD. One prior study has reported a protective effect of a GLP-1 analogue on midbrain dopamine neurons following injection of α-syn preformed fibrils (PFF) into the striatum. Here, we used olfactory bulb injections of PFF as a model of prodromal PD and monitored the effect of a long-acting GLP-1 analogue on the propagation of α-syn pathology in the olfactory system. Thirteen weeks after PFF injection, mice treated with long-acting the GLP-1 analogue had a significant increase in pathological α-syn in brain regions connected to the olfactory bulb, accompanied by signs of microglia activation. Our results suggest that the nature of the neuronal insult and intrinsic properties of the targeted neuronal population markedly influence the effect of GLP-1 analogues.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Glucagon-Like Peptide 1; Injections, Subcutaneous; Male; Mice; Mice, Inbred C57BL; Parkinson Disease, Secondary; Prodromal Symptoms

Alpha-synuclein (α-syn) aggregation is the hallmark pathological lesion in brains of patients with Parkinson's disease (PD) and related neurological disorders characterized as synucleinopathies. Accumulating evidence now indicates that α-syn deposition is also present within the gut and other peripheral organs outside the central nervous system (CNS). In the current study, we demonstrate for the first time that α-syn pathology also accumulates within the liver, the main organ responsible for substance clearance and detoxification. We further demonstrate that cultured human hepatocytes readily internalize oligomeric α-syn assemblies mediated, at least in part, by the gap junction protein connexin-32 (Cx32). Moreover, we identified a time-dependent accumulation of α-syn within the liver of three different transgenic (tg) mouse models expressing human α-syn under CNS-specific promoters, despite the lack of α-syn mRNA expression within the liver. Such a brain-to-liver transmission route could be further corroborated by detection of α-syn pathology within the liver of wild type mice one month after a single striatal α-syn injection. In contrast to the synucleinopathy models, aged mice modeling AD rarely show any amyloid-beta (Aß) deposition within the liver. In human post-mortem liver tissue, we identified cases with neuropathologically confirmed α-syn pathology containing α-syn within hepatocellular structures to a higher degree (75%) than control subjects without α-syn accumulation in the brain (57%). Our results reveal that α-syn accumulates within the liver and may be derived from the brain or other peripheral sources. Collectively, our findings indicate that the liver may play a role in the clearance and detoxification of pathological proteins in PD and related synucleinopathies.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Female; Humans; Lewy Body Disease; Liver; Male; Mice; Mice, Transgenic; Microscopy, Electron, Transmission; Parkinson Disease; Synucleinopathies

D620N mutation in the vacuolar protein sorting 35 ortholog (VPS35) gene causes late-onset, autosomal dominant familial Parkinson's disease (PD) and contributes to idiopathic PD. However, how D620N mutation leads to PD-related deficits in vivo remains unclear. In the present study, we thoroughly characterized the biochemical, pathological, and behavioral changes of a VPS35 D620N knockin (KI) mouse model with chronic aging. We reported that this VPS35 D620N KI model recapitulated a spectrum of cardinal features of PD at 14 months of age which included age-dependent progressive motor deficits, significant changes in the levels of dopamine (DA) and DA metabolites in the striatum, and robust neurodegeneration of the DA neurons in the SNpc and DA terminals in the striatum, accompanied by increased neuroinflammation, and accumulation and aggregation of α-synuclein in DA neurons. Mechanistically, D620N mutation induced mitochondrial fragmentation and dysfunction in aged mice likely through enhanced VPS35-DLP1 interaction and increased turnover of mitochondrial DLP1 complexes in vivo. Finally, the VPS35 D620N KI mice displayed greater susceptibility to MPTP-mediated degeneration of nigrostriatal pathway, indicating that VPS35 D620N mutation increased vulnerability of DA neurons to environmental toxins. Overall, this VPS35 D620N KI mouse model provides a powerful tool for future disease modeling and pharmacological studies of PD. Our data support the involvement of VPS35 in the development of α-synuclein pathology in vivo and revealed the important role of mitochondrial fragmentation/dysfunction in the pathogenesis of VPS35 D620N mutation-associated PD in vivo.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Gene Knock-In Techniques; Mice; Mitochondria; Parkinsonian Disorders; Vesicular Transport Proteins

Parkinson's disease (PD) is a prevalent motor disease caused by the accumulation of mutated α-synuclein (α-Syn); however, its early stages are also characterized by non-motor symptoms, such as olfactory loss, cognitive decline, depression, and anxiety. The therapeutic effects of environmental enrichment (EE) on motor recovery have been reported, but its effects on non-motor symptoms remain unclear. Herein, we reveal the beneficial effects of EE on PD-related non-motor symptoms and changes in synaptic plasticity in the nucleus accumbens. To investigate its therapeutic effects in the early phase of PD, we randomly assigned eight-month-old mice overexpressing human A53T (hA53T) α-Syn to either the EE or standard condition groups for two months. Next, we performed behavioral tests and biochemical and histological analyses at 10 months of age. EE significantly alleviated locomotor hyperactivity and anxiety during the early stages of PD. It normalized the levels of tyrosine hydroxylase, phosphorylated and oligomeric α-Syn, and soluble

Topics: alpha-Synuclein; Animals; Anxiety; Anxiety Disorders; Disease Models, Animal; Humans; Locomotion; Mice; Mice, Transgenic; Parkinson Disease; Tyrosine 3-Monooxygenase; Vesicle-Associated Membrane Protein 2

Topics: alpha-Synuclein; Amino Acid Substitution; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Glycoconjugates; Humans; Indans; Injections, Intraventricular; Locus Coeruleus; Male; Mesencephalon; Methylamines; Mice; Mice, Transgenic; Norepinephrine; Oligonucleotides, Antisense; Parkinson Disease; Pars Compacta; Point Mutation; Synaptic Transmission

Alzheimer's disease affects millions of lives worldwide. This terminal disease is characterized by the formation of amyloid aggregates, so-called amyloid oligomers. These oligomers are composed of β-sheet structures, which are believed to be neurotoxic. However, the actual secondary structure that contributes most to neurotoxicity remains unknown. This lack of knowledge is due to the challenging nature of characterizing the secondary structure of amyloids in cells. To overcome this and investigate the molecular changes in proteins directly in cells, we used synchrotron-based infrared microspectroscopy, a label-free and non-destructive technique available for in situ molecular imaging, to detect structural changes in proteins and lipids. Specifically, we evaluated the formation of β-sheet structures in different monogenic and bigenic cellular models of Alzheimer's disease that we generated for this study. We report on the possibility to discern different amyloid signatures directly in cells using infrared microspectroscopy and demonstrate that bigenic (amyloid-β, α-synuclein) and (amyloid-β, Tau) neuron-like cells display changes in β-sheet load. Altogether, our findings support the notion that different molecular mechanisms of amyloid aggregation, as opposed to a common mechanism, are triggered by the specific cellular environment and, therefore, that various mechanisms lead to the development of Alzheimer's disease.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Amyloidosis; Animals; Cell Line, Tumor; Disease Models, Animal; Humans; Mice; Microscopy, Fluorescence; Neuroblastoma; Neurodegenerative Diseases; Neurons; Protein Conformation; Protein Structure, Secondary; Spectrophotometry, Infrared; Spectroscopy, Fourier Transform Infrared; Synchrotrons

Multiple system atrophy (MSA) is a rare, but fatal atypical parkinsonian disorder. The prototypical pathological hallmark are oligodendroglial cytoplasmic inclusions (GCIs) containing alpha-synuclein (α-syn). Currently, two MSA phenotypes are classified: the parkinsonian (MSA-P) and the cerebellar subtype (MSA-C), clinically characterized by predominant parkinsonism or cerebellar ataxia, respectively. Previous studies have shown that the transgenic MSA mouse model overexpressing human α-syn controlled by the oligodendroglial myelin basic protein (MBP) promoter (MBP29-hα-syn mice) mirrors crucial characteristics of the MSA-P subtype. However, it remains elusive, whether this model recapitulates important features of the MSA-C-related phenotype. First, we examined MSA-C-associated cerebellar pathology using human post-mortem tissue of MSA-C patients and controls. We observed the prototypical GCI pathology and a preserved number of oligodendrocytes in the cerebellar white matter (cbw) accompanied by severe myelin deficit, microgliosis, and a profound loss of Purkinje cells. Secondly, we phenotypically characterized MBP29-hα-syn mice using a dual approach: structural analysis of the hindbrain and functional assessment of gait. Matching the neuropathological features of MSA-C, GCI pathology within the cbw of MBP29-hα-syn mice was accompanied by a severe myelin deficit despite an increased number of oligodendrocytes and a high number of myeloid cells even at an early disease stage. Intriguingly, MBP29-hα-syn mice developed a significant loss of Purkinje cells at a more advanced disease stage. Catwalk XT gait analysis revealed decreased walking speed, increased stride length and width between hind paws. In addition, less dual diagonal support was observed toward more dual lateral and three paw support. Taken together, this wide-based and unsteady gait reflects cerebellar ataxia presumably linked to the cerebellar pathology in MBP29-hα-syn mice. In conclusion, the present study strongly supports the notion that the MBP29-hα-syn mouse model mimics important characteristics of the MSA-C subtype providing a powerful preclinical tool for evaluating future interventional strategies.

Topics: Aged; alpha-Synuclein; Animals; Cerebellar Ataxia; Cerebellum; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Transgenic; Middle Aged; Multiple System Atrophy

We have previously reported that cambinol (DDL-112), a known inhibitor of neutral sphingomyelinase-2 (nSMase2), suppressed extracellular vesicle (EV)/exosome production in vitro in a cell model and reduced tau seed propagation. The enzyme nSMase2 is involved in the production of exosomes carrying proteopathic seeds and could contribute to cell-to-cell transmission of pathological protein aggregates implicated in neurodegenerative diseases such as Parkinson's disease (PD). Here, we performed in vivo studies to determine if DDL-112 can reduce brain EV/exosome production and proteopathic alpha synuclein (αSyn) spread in a PD mouse model.. The acute effects of single-dose treatment with DDL-112 on interleukin-1β-induced extracellular vesicle (EV) release in brain tissue of Thy1-αSyn PD model mice and chronic effects of 5 week DDL-112 treatment on behavioral/motor function and proteinase K-resistant αSyn aggregates in the PD model were determined.. In the acute study, pre-treatment with DDL-112 reduced EV/exosome biogenesis and in the chronic study, treatment with DDL-112 was associated with a reduction in αSyn aggregates in the substantia nigra and improvement in motor function. Inhibition of nSMase2 thus offers a new approach to therapeutic development for neurodegenerative diseases with the potential to reduce the spread of disease-specific proteopathic proteins.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Enzyme Inhibitors; Exosomes; Mice, Transgenic; Naphthalenes; Parkinson Disease; Protein Aggregates; Pyrimidinones; Sirtuins; Sphingomyelin Phosphodiesterase

Mounting evidence suggests that mitochondrial dysfunction and impaired mitophagy lead to Parkinson's disease (PD). Quercetin, one of the most abundant polyphenolic flavonoids, displays many health-promoting biological effects in many diseases. We explored the neuroprotective effect of quercetin

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Disease Models, Animal; Gene Knockdown Techniques; HeLa Cells; Humans; Male; Mitochondria; Mitophagy; Neurons; Neuroprotective Agents; Oxidative Stress; Oxidopamine; Parkinson Disease, Secondary; Protein Kinases; Quercetin; Rats; Ubiquitin-Protein Ligases

Neuroinflammation is the key factor associated with the progression of Parkinson's disease (PD). Pramipexole (PPX) has anti-inflammatory and antioxidant properties. This study explored the effects of PPX on PD and its related mechanisms. A PD rat model was established using 6-hydroxydopamine (6-OHDA). Thirty rats were divided into the following three groups: control, PD, and PD + PPX. The rats in the PD and PD + PPX groups were first administered 6-OHDA and then respectively treated with saline and PPX. Afterward, rotational behavior tests were performed to evaluate the efficiency of PPX. The level of tyrosine hydroxylase (TH) was measured using immunohistochemical staining. Subsequently, real-time quantitative PCR (RT-qPCR) and western blot were used to determine the expression of α-synuclein (α-syn), nuclear receptor subfamily 4 group A member 2 (Nurr1), and nuclear factor kappa B (NF-κB). PPX improved the motor behavior of PD rats caused by 6-OHDA. The number of TH-positive neurons in the PD group was significantly lower than that in the control group (P < 0.05), while PPX could rescue 6-OHDA-induced TH loss. RT-qPCR and western blot showed that Nurr1 expression was significantly downregulated in the PD group compared to that of the control group (P < 0.05), while after PPX treatment, its expression was significantly upregulated (P < 0.05). For α-syn and NF-κB, 6-OHDA significantly upregulated their expressions (P < 0.05), whereas PPX reversed them. PPX improved the motor behavior of PD through mediating the inflammatory response and regulating the Nurr1/NF-κB signaling pathway.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Disease Models, Animal; NF-kappa B; Nuclear Receptor Subfamily 4, Group A, Member 2; Oxidopamine; Parkinson Disease; Pramipexole; Rats; Signal Transduction

Alterations in mitochondrial function and morphology are associated with many human diseases, including cancer and neurodegenerative diseases. Mitochondrial impairment is linked to Parkinson's disease (PD) pathogenesis, and alterations in mitochondrial dynamics are seen in PD models. In particular, α-synuclein (αS) abnormalities are often associated with pathological changes to mitochondria. However, the relationship between αS pathology and mitochondrial dynamics remains poorly defined. Herein, we examined a mouse model of α-synucleinopathy for αS pathology-linked alterations in mitochondrial dynamics in vivo. We show that α-synucleinopathy in a transgenic (Tg) mouse model expressing familial PD-linked mutant A53T human αS (TgA53T) is associated with a decrease in Drp1 localization and activity in the mitochondria. In addition, we show that the loss of Drp1 function in the mitochondria is associated with two distinct phenotypes of enlarged neuronal mitochondria. Mitochondrial enlargement was only present in diseased animals and, apart from Drp1, other proteins involved in mitochondrial dynamics are unlikely to cause these changes, as their levels remained mostly unchanged. Further, the levels of Mfn1, a protein that facilitates mitochondrial fusion, was decreased nonspecifically with transgene expression. These results support the view that altered mitochondrial dynamics are a significant neuropathological factor in α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain Stem; Cerebral Cortex; Disease Models, Animal; Dynamins; Gene Expression Regulation; GTP Phosphohydrolases; Humans; Mice; Mice, Transgenic; Mitochondria; Mitochondrial Dynamics; Mutation; Neurons; Parkinson Disease; Phosphorylation; Signal Transduction; Spinal Cord

In synucleinopathies such as Parkinson's disease (PD) and dementia with Lewy body (DLB), pathological alpha-synuclein (α-syn) aggregates are found in the gastrointestinal (GI) tract as well as in the brain. In this study, using real-time quaking-induced conversion (RT-QuIC), we investigated the presence of α-syn seeding activity in the brain and colon tissue of G2-3 transgenic mice expressing human A53T α-syn. Here we show that pathological α-syn aggregates with seeding activity were present in the colon of G2-3 mice as early as 3 months old, which is in the presymptomatic stage prior to the observation of any neurological abnormalities. In contrast, α-syn seeding activity was not detectable in 3 month-old mouse brains and only identified at 6 months of age in one of three mice. In the symptomatic stage of 12 months of age, RT-QuIC seeding activity was consistently detectable in both the brain and colon of G2-3 mice. Our results indicate that the RT-QuIC assay can presymptomatically detect pathological α-syn aggregates in the colon of G2-3 mice several months prior to their detection in brain tissue.

Topics: alpha-Synuclein; Animals; Biological Assay; Brain; Colon; Disease Models, Animal; Disease Susceptibility; Humans; Mice; Mice, Transgenic; Synucleinopathies

A molecular hallmark in Parkinson's disease (PD) pathogenesis are α-synuclein aggregates. Cerebral dopamine neurotrophic factor (CDNF) is an atypical growth factor that is mostly resident in the endoplasmic reticulum but exerts its effects both intracellularly and extracellularly. One of the beneficial effects of CDNF can be protecting neurons from the toxic effects of α-synuclein. Here, we investigated the effects of CDNF on α-synuclein aggregation in vitro and in vivo. We found that CDNF directly interacts with α-synuclein with a K

Topics: alpha-Synuclein; Animals; Binding Sites; Cell Line; Disease Models, Animal; Dopamine; Humans; Magnetic Resonance Spectroscopy; Male; Mice; Models, Molecular; Nerve Growth Factors; Parkinson Disease; Phosphorylation; Primary Cell Culture; Protein Aggregates; Protein Binding; Protein Conformation; Rats; Substantia Nigra

Heterozygous point mutations of α-synuclein (α-syn) have been linked to the early onset and rapid progression of familial Parkinson's diseases (fPD). However, the interplay between hereditary mutant and wild-type (WT) α-syn and its role in the exacerbated pathology of α-syn in fPD progression are poorly understood. Here, we find that WT mice inoculated with the human E46K mutant α-syn fibril (hE46K) strain develop early-onset motor deficit and morphologically different α-syn aggregation compared with those inoculated with the human WT fibril (hWT) strain. By using cryo-electron microscopy, we reveal at the near-atomic level that the hE46K strain induces both human and mouse WT α-syn monomers to form the fibril structure of the hE46K strain. Moreover, the induced hWT strain inherits most of the pathological traits of the hE46K strain as well. Our work suggests that the structural and pathological features of mutant strains could be propagated by the WT α-syn in such a way that the mutant pathology would be amplified in fPD.

Topics: alpha-Synuclein; Amyloid; Animals; Cryoelectron Microscopy; Disease Models, Animal; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Atomic Force; Microscopy, Confocal; Motor Activity; Mutation, Missense; Nervous System Diseases; Parkinson Disease; Protein Aggregation, Pathological

Parkinson's disease (PD) is frequently associated with a prodromal sensory neuropathy manifesting with sensory loss and chronic pain. We have recently shown that PD-associated sensory neuropathy in patients is associated with high levels of glucosylceramides. Here, we assessed the underlying pathology and mechanisms in Pink1. We studied nociceptive and olfactory behaviour and the neuropathology of dorsal root ganglia (DRGs), including ultrastructure, mitochondrial respiration, transcriptomes, outgrowth and calcium currents of primary neurons, and tissue ceramides and sphingolipids before the onset of a PD-like disease that spontaneously develops in Pink1. Similar to PD patients, Pink1. The results suggest that pathological GlcCer contribute to prodromal sensory disease in PD mice via mitochondrial damage and calcium channel hyperexcitability. GlcCer-associated sensory neuron pathology might be amenable to GlcCer lowering therapeutic strategies.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mitochondria; Mutation; Neurons; Parkinson Disease; Parkinsonian Disorders; Protein Kinases

Parkinson's disease (PD) is one of the most common neurodegenerative motor disorders, and is characterized by the presence of Lewy bodies containing misfolded α-synuclein (α-syn) and by selective degeneration of midbrain dopamine neurons. Studies have shown that upregulation of ubiquitin-proteasome system (UPS) activity promotes the clearance of aggregation-prone proteins such as α-syn and Tau, so as to alleviate the neuropathology of neurodegenerative diseases.. To identify and investigate lycorine as a UPS enhancer able to decrease α-syn in transgenic PD models.. Dot blot was used to screen α-syn-lowering compounds in an inducible α-syn overexpression cell model. Inducible wild-type (WT) and mutant α-syn-overexpressing PC12 cells, WT α-syn-overexpressing N2a cells and primary cultured neurons from A53T transgenic mice were used to evaluate the effects of lycorine on α-syn degradation in vitro. Heterozygous A53T transgenic mice were used to evaluate the effects of lycorine on α-syn degradation in vivo. mCherry-GFP-LC3 reporter was used to detect autophagy-dependent degradation. Ub-R-GFP and Ub-G76V-GFP reporters were used to detect UPS-dependent degradation. Proteasome activity was detected by fluorogenic substrate Suc-Leu-Leu-Val-Tyr-AMC (Suc-LLVY-AMC).. Lycorine significantly promoted clearance of over-expressed WT and mutant α-syn in neuronal cell lines and primary cultured neurons. More importantly, 15 days' intraperitoneal administration of lycorine effectively promoted the degradation of α-syn in the brains of A53T transgenic mice. Mechanistically, lycorine accelerated α-syn degradation by activating cAMP-dependent protein kinase (PKA) to promote proteasome activity.. Lycorine is a novel α-syn-lowering compound that works through PKA-mediated UPS activation. This ability to lower α-syn implies that lycorine has the potential to be developed as a pharmaceutical for the treatment of neurodegenerative diseases, such as PD, associated with UPS impairment and protein aggregations.

Topics: alpha-Synuclein; Amaryllidaceae Alkaloids; Animals; Autophagy; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Humans; Male; Mice, Transgenic; Neuroprotective Agents; Parkinson Disease; PC12 Cells; Phenanthridines; Proteasome Endopeptidase Complex; Rats; Ubiquitin; Up-Regulation

Parkinson's disease (PD) is pathologically characterized by intraneuronal α-synuclein (α-Syn) inclusions called Lewy bodies (LBs) and the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Autopsy studies have suggested that Lewy pathology initially occurs in the olfactory bulb and enteric nervous system, subsequently spreading in the brain stereotypically. Recent studies have demonstrated that templated fibrillization and intercellular dissemination of misfolded α-Syn underlie this pathological progression. Injection of animals with α-Syn preformed fibrils (PFFs) can recapitulate LB-like inclusions and the subsequent intercellular transmission of α-Syn pathology. Moreover, targeting specific brain regions or body parts enables the generation of unique models depending on the injection sites. These features of α-Syn PFF-injected animal models provide a platform to explore disease mechanisms and to test disease modifying therapies in PD research. Here, we describe a methodology for the generation of α-Syn PFFs and the surgery on mice.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Enteric Nervous System; Humans; Inclusion Bodies; Mice; Parkinson Disease; Substantia Nigra

The propagation of assembled α-synuclein (αS) is key to understanding the pathological mechanisms of synucleinopathies such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy.Here we describe a nonhuman primate model of αS propagation using common marmosets (Callithrix jacchus) with an intracerebral injection of synthetic preformed αS fibrils. This protocol enables observation of the formation of phosphorylated αS pathology and its propagation three months after the injection.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Brain; Callithrix; Disease Models, Animal; Phosphorylation; Synucleinopathies

The capacity of the secretome from bone marrow-derived mesenchymal stem cells (BMSCs) to prevent dopaminergic neuron degeneration caused by overexpression of alpha-synuclein (α-syn) was explored using two Caenorhabditis elegans models of Parkinson's disease (PD).. First, a more predictive model of PD that overexpresses α-syn in dopamine neurons was subjected to chronic treatment with secretome. This strain displays progressive dopaminergic neurodegeneration that is age-dependent. Following chronic treatment with secretome, the number of intact dopaminergic neurons was determined. Following these initial experiments, a C. elegans strain that overexpresses α-syn in body wall muscle cells was used to determine the impact of hBMSC secretome on α-syn inclusions. Lastly, in silico analysis of the components that constitute the secretome was performed.. The human BMSC (hBMSC) secretome induced a neuroprotective effect, leading to reduced dopaminergic neurodegeneration. Moreover, in animals submitted to chronic treatment with secretome, the number of α-syn inclusions was reduced, indicating that the secretome of MSCs was possibly contributing to the degradation of those structures. In silico analysis identified possible suppressors of α-syn proteotoxicity, including growth factors and players in the neuronal protein quality control mechanisms.. The present findings indicate that hBMSC secretome has the potential to be used as a disease-modifying strategy in future PD regenerative medicine approaches.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Humans; Mesenchymal Stem Cells; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder that results in motor dysfunction and, eventually, cognitive impairment. α-Synuclein protein is known as a central protein to the pathophysiology of PD, but the underlying pathological mechanism still remains to be elucidated. In an effort to understand how α-synuclein underlies the pathology of PD, various PD mouse models with α-synuclein overexpression have been developed. However, systemic analysis of the brain proteome of those mouse models is lacking. In this study, we established two mouse models of PD by injecting α-synuclein preformed fibrils (PFF) or by inducing overexpression of human A53T α-synuclein to investigate common pathways in the two different types of the PD mouse models. For more accurate quantification of mouse brain proteome, the proteins were quantified using the method of stable isotope labeling with amino acids in mammals . We identified a total of 8355 proteins from the two mouse models; ∼6800 and ∼7200 proteins from α-synuclein PFF-injected mice and human A53T α-synuclein transgenic mice, respectively. Through pathway analysis of the differentially expressed proteins common to both PD mouse models, it was discovered that the complement and coagulation cascade pathways were enriched in the PD mice compared to control animals. Notably, a validation study demonstrated that complement component 3 (C3)-positive astrocytes were increased in the ventral midbrain of the intrastriatal α-synuclein PFF-injected mice and C3 secreted from astrocytes could induce the degeneration of dopaminergic neurons. This is the first study that highlights the significance of the complement and coagulation pathways in the pathogenesis of PD through proteome analyses with two sophisticated mouse models of PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Humans; Mice; Mice, Transgenic; Parkinson Disease

α-Synuclein (α-syn) is a hallmark amyloidogenic protein component of Lewy bodies in dopaminergic neurons affected by Parkinson's disease (PD). Despite the multi-faceted gene regulation of α-syn in the nucleus, the mechanism underlying α-syn crosstalk in chromatin remodeling in PD pathogenesis remains elusive. Here, we identified transcriptional adapter 2-alpha (TADA2a) as a novel binding partner of α-syn using the BioID system. TADA2a is a component of the p300/CBP-associated factor and is related to histone H3/H4 acetylation. We found that α-syn A53T was more preferentially localized in the nucleus than the α-syn wild-type (WT), leading to a stronger disturbance of TADA2a. Indeed, α-syn A53T significantly reduced the level of histone H3 acetylation in SH-SY5Y cells; its reduction was also evident in the striatum (STR) and substantia nigra (SN) of mice that were stereotaxically injected with α-syn preformed fibrils (PFFs). Interestingly, α-syn PFF injection resulted in a decrease in TADA2a in the STR and SN of α-syn PFF-injected mice. Furthermore, the levels of TADA2a and acetylated histone H3 were significantly decreased in the SN of patients with PD. Therefore, histone modification through α-syn A53T-TADA2a interaction may be associated with α-syn-mediated neurotoxicity in PD pathology.

Topics: Acetylation; alpha-Synuclein; Animals; Cell Line, Tumor; Corpus Striatum; Disease Models, Animal; DNA-Binding Proteins; Dopaminergic Neurons; Histones; Humans; Lewy Bodies; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Parkinson Disease; Substantia Nigra; Transcription Factors

Cross seeding between amyloidogenic proteins in the gut is receiving increasing attention as a possible mechanism for initiation or acceleration of amyloid formation by aggregation-prone proteins such as αSN, which is central in the development of Parkinson's disease (PD). This is particularly pertinent in view of the growing number of functional (i.e., benign and useful) amyloid proteins discovered in bacteria. Here we identify two amyloidogenic proteins, Pr12 and Pr17, in fecal matter from PD transgenic rats and their wild type counterparts, based on their stability against dissolution by formic acid (FA). Both proteins show robust aggregation into ThT-positive aggregates that contain higher-order β-sheets and have a fibrillar morphology, indicative of amyloid proteins. In addition, Pr17 aggregates formed in vitro showed significant resistance against FA, suggesting an ability to form highly stable amyloid. Treatment with proteinase K revealed a protected core of approx. 9 kDa. Neither Pr12 nor Pr17, however, affected αSN aggregation in vitro. Thus, amyloidogenicity does not per se lead to an ability to cross-seed fibrillation of αSN. Our results support the use of proteomics and FA to identify amyloidogenic protein in complex mixtures and suggests that there may be numerous functional amyloid proteins in microbiomes.

Topics: alpha-Synuclein; Amino Acid Sequence; Amyloid; Amyloidogenic Proteins; Animals; Bacterial Proteins; Benzothiazoles; Biofilms; Disease Models, Animal; Endopeptidase K; Feces; Female; Formates; Gastrointestinal Microbiome; Humans; Hydrogen-Ion Concentration; Microbial Consortia; Parkinson Disease; Protein Aggregates; Rats; Rats, Transgenic; Urea

Synucleinopathy disorders are characterized by aggregates of α-synuclein (α-syn), which engage microglia to elicit a neuroinflammatory response. Here, we determined the gene expression and DNA methylation changes in microglia induced by aggregate α-syn. Transgenic murine Thy-1 promoter (mThy1)-Asyn mice overexpressing human α-syn are a model of synucleinopathy. Microglia from 3 and 13-month-old mice were used to isolate nucleic acids for methylated DNA and RNA-sequencing. α-Syn-regulated changes in gene expression and genomic methylation were determined and examined for functional enrichment followed by network analysis to further elucidate possible connections within the data. Microglial DNA isolated from our 3-month cohort had 5315 differentially methylated gene (DMG) changes, while RNA levels demonstrated a change in 119 differentially expressed genes (DEGs) between mThy1-Asyn mice and wild-type littermate controls. The 3-month DEGs and DMGs were highly associated with adhesion and migration signaling, suggesting a phenotypic transition from resting to active microglia. We observed 3742 DMGs and 3766 DEGs in 13-month mThy1-Asyn mice. These genes were often related to adhesion, migration, cell cycle, cellular metabolism, and immune response. Network analysis also showed increased cell mobility and inflammatory functions at 3 months, shifting to cell cycle, immune response, and metabolism changes at 13 months. We observed significant α-syn-induced methylation and gene expression changes in microglia. Our data suggest that α-syn overexpression initiates microglial activation leading to neuroinflammation and cellular metabolic stresses, which is associated with disease progression.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; DNA Methylation; Gene Expression; Inflammation; Mice; Mice, Inbred C57BL; Microglia

Synucleinopathies are neurodegenerative diseases in which α-synuclein protein accumulates in neurons and glia. In these diseases, α-synuclein forms dense intracellular aggregates that are disease hallmarks and actively contribute to tissue pathology. Interestingly, many pathological mechanisms, including iron accumulation and lipid peroxidation, are shared between classical synucleinopathies such as Alzheimer's disease, Parkinson's disease and traumatic spinal cord injury (SCI). However, to date, no studies have determined if α-synuclein accumulation occurs after human SCI. To examine this, cross-sections from injured and non-injured human spinal cords were immunolabeled for α-synuclein. This showed robust α-synuclein accumulation in profiles resembling axons and astrocytes in tissue surrounding the injury, revealing that α-synuclein markedly aggregates in traumatically injured human spinal cords. We also detected significant iron deposition in the injury site, a known catalyst for α-synuclein aggregation. Next a rodent SCI model mimicking the histological features of human SCI revealed aggregates and structurally altered monomers of α-synuclein are present after SCI. To determine if α-synuclein exacerbates SCI pathology, α-synuclein knockout mice were tested. Compared to wild type mice, α-synuclein knockout mice had significantly more spared axons and neurons and lower pro-inflammatory mediators, macrophage accumulation, and iron deposition in the injured spinal cord. Interestingly, locomotor analysis revealed that α-synuclein may be essential for dopamine-mediated hindlimb function after SCI. Collectively, the marked upregulation and long-lasting accumulation of α-synuclein and iron suggests that SCI may fit within the family of synucleinopathies and offer new therapeutic targets for promoting neuron preservation and improving function after spinal trauma.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Animals; Astrocytes; Biomarkers; Cell Death; Disease Models, Animal; Dopamine; Female; Gene Knockdown Techniques; Humans; Inflammation; Inflammation Mediators; Iron; Male; Mice; Middle Aged; Neurons; Organ Size; Rats; Rodentia; Signal Transduction; Spinal Cord; Spinal Cord Injuries; Young Adult

Parkinson's disease (PD) is characterized by Lewy bodies (composed predominantly of alpha-synuclein [aSyn]) and loss of pigmented midbrain dopaminergic neurons comprising the nigrostriatal pathway. Most PD patients show significant deficiency of gangliosides, including GM1, in the brain, and GM1 ganglioside appears to keep dopaminergic neurons functioning properly. Thus, supplementation of GM1 could potentially provide some rescuing effects. In this study, we demonstrate that intranasal infusion of GD3 and GM1 gangliosides reduces intracellular aSyn levels. GM1 also significantly enhances expression of tyrosine hydroxylase (TH) in the substantia nigra pars compacta of the A53T aSyn overexpressing mouse, following restored nuclear expression of nuclear receptor related 1 (Nurr1, also known as NR4A2), an essential transcription factor for differentiation, maturation, and maintenance of midbrain dopaminergic neurons. GM1 induces epigenetic activation of the TH gene, including augmentation of acetylated histones and recruitment of Nurr1 to the TH promoter region. Our data indicate that intranasal administration of gangliosides could reduce neurotoxic proteins and restore functional neurons via modulating chromatin status by nuclear gangliosides.

Topics: Administration, Intranasal; alpha-Synuclein; Animals; Cell Line; Disease Models, Animal; Down-Regulation; Epigenesis, Genetic; G(M1) Ganglioside; Gangliosides; Gene Expression Regulation; Humans; Male; Mice; Parkinson Disease; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a debilitating neurodegenerative disorder. Early symptoms include motor dysfunction and impaired olfaction. Toxic aggregation of α-synuclein (aSyn) in the olfactory bulb (OB) and substantia nigra pars compacta (SNpc) is a hallmark of PD neuropathology. Intranasal (IN) carnosine (2 mg/d for 8 weeks) was previously demonstrated to improve motor behavior and mitochondrial function in Thy1-aSyn mice, a model of PD. The present studies evaluated the efficacy of IN carnosine at a higher dose in slowing progression of motor deficits and aSyn accumulation in Thy1-aSyn mice. After baseline neurobehavioral assessments, IN carnosine was administered (0.0, 2.0, or 4.0 mg/day) to wild-type and Thy1-aSyn mice for 8 weeks. Olfactory and motor behavioral measurements were repeated prior to end point tissue collection. Brain sections were immunostained for aSyn and tyrosine hydroxylase (TH). Immunopositive cells were counted using design-based stereology in the SNpc and OB mitral cell layer (MCL). Behavioral assessments revealed a dose-dependent improvement in motor function with increasing carnosine dose. Thy1-aSyn mice treated with 2.0 or 4.0 mg/d IN carnosine exhibited fewer aSyn-positive (aSyn(+)) cell bodies in the SNpc compared to vehicle-treated mice. Moreover, the number of aSyn(+) cell bodies in carnosine-treated Thy1-aSyn mice was reduced to vehicle-treated wild-type levels in the SNpc. Carnosine treatment did not affect the number of aSyn(+) cell bodies in the OB-MCL or the number of TH(+) cells in the SNpc. In summary, intranasal carnosine treatment decreased aSyn accumulation in the SNpc, which may underlie its mitigation of motor deficits in the Thy1-aSyn mice.

Topics: alpha-Synuclein; Animals; Carnosine; Disease Models, Animal; Mice; Mice, Transgenic; Parkinson Disease

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Parkinson Disease; Synucleinopathies

Delayed neurocognitive recovery (dNCR) is a major complication after anesthesia and surgery in older adults. Alpha-synuclein (

Topics: alpha-Synuclein; Animals; Apoptosis; Cognitive Behavioral Therapy; Disease Models, Animal; Humans; Mice; Postoperative Period

Therapeutic options for Parkinson's disease (PD) are limited to a symptomatic approach, making it a global threat. Targeting aggregated alpha-synuclein (α-syn) clearance is a gold standard for ameliorating PD pathology, bringing autophagy into the limelight. Expression of autophagy related genes are under the regulation by histone modifications, however, its relevance in PD is yet to be established. Here, preformed fibrillar form (PFF) of α-syn was used to induce PD in wistar rats, which were thereafter subjected to treatment with trehalose (tre, 4g/kg, orally), a potent autophagy inducer and sodium butyrate (SB, 300 mg/kg, orally), a pan histone deacetylase inhibitor alone as well as in combination. The combination treatment significantly reduced motor deficits as evidenced after rotarod, narrow beam walk, and open field tests. Novel object location and recognition tests were performed to govern cognitive abnormality associated with advanced stage PD, which was overcome by the combination treatment. Additionally, with the combination, the level of pro-inflammatory cytokines were significantly reduced, along with elevated levels of dopamine and histone H3 acetylation. Further, mRNA analysis revealed that levels of certain autophagy related genes and proteins implicated in PD pathogenesis significantly improved after administration of both tre and SB. Immunofluorescence and H&E staining in the substantia nigra region mirrored a potential improvement after treatment with both tre and SB. Therefore, outcomes of the present study were adequate to prove that combinatorial efficacy with tre and SB may prove to be a formidable insight into ameliorating PD exacerbated by PFF α-syn as compared to its individual efficacy.

Topics: alpha-Synuclein; Animals; Butyric Acid; Disease Models, Animal; Neuroprotective Agents; Parkinson Disease; Rats; Rats, Wistar; Trehalose

Alpha-synuclein (α-syn) and leucine-rich repeat kinase 2 (LRRK2) play crucial roles in Parkinson's disease (PD). They may functionally interact to induce the degeneration of dopaminergic (DA) neurons via mechanisms that are not yet fully understood. We previously showed that the C-terminal portion of LRRK2 (ΔLRRK2) with the G2019S mutation (ΔLRRK2

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutant Proteins; Mutation; Protein Domains; Rats

Alpha-synuclein (α-syn) preformed fibril (PFF)-induced pathology can be used to study the features and progression of synucleinopathies, such as Parkinson's disease. Intrastriatal injection of mouse α-syn PFFs produce accumulation of α-syn pathology in both mice and rats. Previous studies in mice have revealed that greater sequence homology between the α-syn amino acid sequence used to produce PFFs with that of the endogenous host α-syn increases α-syn pathology in vivo.. Based on the prediction that greater sequence homology will result in more α-syn pathology, PFFs generated from recombinant rat α-syn (rPFFs) were used instead of PFFs produced from recombinant mouse α-syn (mPFFs), which are normally used in the model. Rats received unilateral intrastriatal injections of either rPFFs or mPFFs and accumulation of α-syn phosphorylated at serine 129 (pSyn) was examined at 1-month post-surgery.. Rats injected with mPFFs exhibited abundant accumulation of α-syn inclusions in the substantia nigra and cortical regions, whereas in rats injected with rPFFs had significantly fewer SNpc neurons containing pSyn inclusions (≈60% fewer) and little, if any, pSyn inclusions were observed in the cortex.. Our results suggest that additional factors beyond the degree of sequence homology between host α-syn and injected recombinant α-syn impact efficiency of seeding and subsequent inclusion formation. More practically, these findings caution against the use of rPFFs in the rat preformed fibril model.

Topics: alpha-Synuclein; Animals; Cerebral Cortex; Disease Models, Animal; Mice; Parkinson Disease; Rats; Recombinant Proteins; Substantia Nigra; Synucleinopathies

Parkinson's disease (PD) is a common neurodegenerative disorder with motor symptoms linked to the loss of dopaminergic neurons in the brain. α-Synuclein is an aggregation-prone neural protein that plays a role in the pathogenesis of PD. In our previous paper, we found that saffron; the stigma of Crocus sativus Linné (Iridaceae), and its constituents (crocin and crocetin) suppressed aggregation of α-synuclein and promoted the dissociation of α-synuclein fibrils in vitro. In this study, we investigated the effect of dietary saffron and its constituent, crocetin, in vivo on a fly PD model overexpressing several mutant α-synuclein in a tissue-specific manner. Saffron and crocetin significantly suppressed the decrease of climbing ability in the Drosophila overexpressing A30P (A30P fly PD model) or G51D (G51D fly PD model) mutated α-synuclein in neurons. Saffron and crocetin extended the life span in the G51D fly PD model. Saffron suppressed the rough-eyed phenotype and the dispersion of the size histogram of the ocular long axis in the eye of A30P fly PD model. Saffron had a cytoprotective effect on a human neuronal cell line with α-synuclein fibrils. These data showed that saffron and its constituent crocetin have protective effects on the progression of PD disease in animals in vivo and suggest that saffron and crocetin can be used to treat PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Carotenoids; Cell Line; Crocus; Disease Models, Animal; Drosophila melanogaster; Female; Humans; Longevity; Male; Motor Activity; Mutation; Neurons; Neuroprotective Agents; Parkinson Disease; Retinal Degeneration; Vitamin A

Synucleinopathies are neurodegenerative disorders involving pathological alpha-synuclein (αSyn) protein, including dementia with Lewy bodies, multiple system atrophy and Parkinson's disease (PD). Current in vivo models of synucleinopathy include transgenic mice overexpressing αSyn variants and methods based on administration of aggregated, exogenous αSyn. Combining these techniques offers the ability to study consequences of introducing pathological αSyn into primed neuronal environments likely to develop synucleinopathy. Herein, we characterize the impacts pre-formed fibrils (PFFs) of recombinant, human αSyn have in mice overexpressing human A30P αSyn, a mutation associated with autosomal dominant PD. A30P mouse brain contains detergent insoluble αSyn biochemically similar to PD brain, and these mice develop Lewy-like synucleinopathy with age. Administration of PFFs in A30P mice resulted in regionally-specific accumulations of phosphorylated synuclein, microglial induction and a motor phenotype that differed from PFF-induced effects in wildtype mice. Surprisingly, PFF-induced losses of tyrosine hydroxylase were similar in A30P and wildtype mice. Thus, the PFF-A30P model recapitulates key aspects of synucleinopathy with induction of microglia, creating an appropriate system for evaluating neurodegenerative therapeutics.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Gene Expression; Mice, Transgenic; Microglia; Parkinson Disease; Synucleinopathies

While misfolding of alpha-synuclein (αSyn) is central to the pathogenesis of Parkinson's disease (PD), fundamental questions about its structure and function at the synapse remain unanswered. We examine synaptosomes from non-transgenic and transgenic mice expressing wild-type human αSyn, the E46K fPD-causing mutation, or an amplified form of E46K ("3K"). Synaptosomes from mice expressing the 3K mutant show reduced Ca

Topics: alpha-Synuclein; Animals; Brain; Calcium; Disease Models, Animal; Exocytosis; Humans; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Models, Biological; Parkinson Disease; Protein Conformation; Protein Folding; Protein Multimerization; Recombinant Proteins; SNARE Proteins; Solubility; Synaptic Vesicles; Synaptosomes

Multiple system atrophy (MSA) is a fatal neurodegenerative disorder characterized by aggregated α-synuclein (α-syn) in oligodendrocytes and accompanied by striatonigral and olivopontocerebellar degeneration and motor symptoms. Key features of MSA are replicated in the PLP-α-syn transgenic mouse, including progressive striatonigral degeneration and motor deterioration. There are currently no approved treatments for MSA. ATH434 is a novel, orally bioavailable brain penetrant small molecule inhibitor of α-syn aggregation.. To characterize ATH434 for disease modification in a mouse model of MSA.. Six-month-old PLP-α-syn mice (MSA mice) were ATH434-treated (ATH434 in food) or untreated (normal food) for 6 months. Motor behavior and numbers of nigral and striatal neurons were evaluated. α-syn aggregates and oligomers were quantified by immunohistochemical and western blot analyses. Microglial activation and neuroinflammation were assessed by histological and molecular analyses. Ferric iron in the Substantia nigra was evaluated with the Perls method.. ATH434-treated mice demonstrated preservation of motor performance in MSA mice that was associated with neuroprotection of nigral and striatal neurons. The rescue of the phenotype correlated with the reduction of α-syn inclusions and oligomers in animals receiving ATH434. ATH434-treated mice exhibited significantly increased lysosomal activity of microglia without increased pro-inflammatory markers, suggesting a role in α-syn clearing. ATH434-treatment was associated with lower intracellular nigral iron levels.. Our findings demonstrate the beneficial disease-modifying effect of ATH434 in oligodendroglial α-synucleinopathy on both the motor phenotype and neurodegenerative pathology in the PLP-α-syn transgenic mouse and support the development of ATH434 for MSA. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Transgenic; Multiple System Atrophy; Oligodendroglia

Parkinson's disease (PD) is the most common movement disorder, characterized by progressive degeneration of the nigrostriatal pathway, which consists of dopaminergic cell bodies in substantia nigra and their neuronal projections to the striatum. Moreover, PD is associated with an array of non-motor symptoms such as olfactory dysfunction, gastrointestinal dysfunction, impaired regulation of the sleep-wake cycle, anxiety, depression, and cognitive impairment. Inflammation and concomitant oxidative stress are crucial in the pathogenesis of PD. Thus, this study aimed to model PD via intrastriatal injection of the inflammagen lipopolysaccharide (LPS)to investigate if the lesion causes olfactory and motor impairments, inflammation, oxidative stress, and alteration in synaptic proteins in the olfactory bulb, striatum, and colon. Ten µg of LPS was injected unilaterally into the striatum of 27 male C57BL/6 mice, and behavioural assessment was conducted at 4 and 8 weeks post-treatment, followed by tissue collection. Intrastriatal LPS induced motor impairment in C57BL/6 mice at 8 weeks post-treatment evidenced by reduced latency time in the rotarod test. LPS also induced inflammation in the striatum characterized by increased expression of microglial marker Iba-1 and astrocytic marker GFAP, with degeneration of dopaminergic neuronal fibres (reduced tyrosine hydroxylase immunoreactivity), and reduction of synaptic proteins and DJ-1 protein. Additionally, intrastriatal LPS induced inflammation, oxidative stress and alterations in synaptic proteins within the olfactory bulb, although this did not induce a significant impairment in olfactory function. Intrastriatal LPS induced mild inflammatory changes in the distal colon, accompanied by increased protein expression of 3-nitrotyrosine-modified proteins. This model recapitulated the major features of PD such as motor impairment and degeneration of dopaminergic neuronal fibres in the striatum, as well as some pathological changes in the olfactory bulb and colon; thus, this model could be suitable for understanding clinical PD and testing neuroprotective strategies.

Topics: alpha-Synuclein; Animals; Astrocytes; Behavior Rating Scale; Brain-Derived Neurotrophic Factor; Calcium-Binding Proteins; Colon; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Glial Fibrillary Acidic Protein; Immunohistochemistry; Inflammation; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Microfilament Proteins; Microglia; Olfactory Bulb; Oxidative Stress; Parkinson Disease; Protein Deglycase DJ-1; Reactive Oxygen Species; Substantia Nigra; Tyrosine 3-Monooxygenase

Topics: 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Astrocytes; Biomarkers; Brain; Cell Line; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p21; Disease Models, Animal; Dopaminergic Neurons; Female; Glial Fibrillary Acidic Protein; HMGB1 Protein; Homeodomain Proteins; Humans; Lamin Type B; Male; Mice, Inbred C57BL; Microglia; Parkinson Disease; Postmortem Changes; Rats

Equine pituitary pars intermedia dysfunction (PPID) is a common endocrine disease of aged horses that shows a similar pathophysiology as Parkinson's Disease (PD) with increased levels of α-synuclein (α-syn). While α-syn is thought to play a pathogenic role in horses with PPID, it is unclear if α-syn is also misfolded in the pars intermedia and could similarly promote self-aggregation and propagation. Consequently, α-syn was isolated from the pars intermedia from groups of healthy young and aged horses, and aged PPID-afflicted horses. Seeding experiments confirmed the prion-like properties of α-syn isolated from PPID-afflicted horses. Next, detection of α-syn fibrils in pars intermedia via transmission electron microscopy (TEM) was exclusive to PPID-afflicted horses. A bank of fragment peptides was designed to further characterize equine α-syn misfolding. Region 62-87 of equine and human α-syn peptides was found to be most prone to aggregation according to Tango bioinformatic program and kinetics of aggregation via a thioflavin T fluorescence assay. In both species, fragment peptide 62-87 is capable of generating mature fibrils as demonstrated by TEM. The combined animal, bioinformatic, and biophysical studies provide evidence that equine α-syn is misfolded in PPID horses.

Topics: Aging; alpha-Synuclein; Animals; Disease Models, Animal; Horse Diseases; Horses; Pituitary Diseases; Pituitary Gland, Intermediate; Synucleinopathies

Gastrointestinal (GI) complications, that severely impact patient quality of life, are a common occurrence in patients with Parkinson's disease (PD). Damage to enteric neurons and the accumulation of alpha-synuclein in the enteric nervous system (ENS) are thought to contribute to this phenotype. Copper or iron chelators, that bind excess or labile metal ions, can prevent aggregation of alpha-synuclein in the brain and alleviate motor-symptoms in preclinical models of PD.. We investigated the effect of ATH434 (formally PBT434), a small molecule, orally bioavailable, moderate-affinity iron chelator, on colonic propulsion and whole gut transit in A53T alpha-synuclein transgenic mice.. Mice were fed ATH434 (30 mg/kg/day) for either 4 months (beginning at ∼15 months of age), after the onset of slowed propulsion ("treatment group"), or for 3 months (beginning at ∼12 months of age), prior to slowed propulsion ("prevention group").. ATH434, given after dysfunction was established, resulted in a reversal of slowed colonic propulsion and gut transit deficits in A53T mice to WT levels. In addition, ATH434 administered from 12 months prevented the slowed bead expulsion at 15 months but did not alter deficits in gut transit time when compared to vehicle-treated A53T mice. The proportion of neurons with nuclear Hu+ translocation, an indicator of neuronal stress in the ENS, was significantly greater in A53T than WT mice, and was reduced in both groups when ATH434 was administered.. ATH434 can reverse some of the GI deficits and enteric neuropathy that occur in a mouse model of PD, and thus may have potential clinical benefit in alleviating the GI dysfunctions associated with PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Gastrointestinal Diseases; Mice; Mice, Transgenic; Parkinson Disease

Growing evidence suggests that human gut bacteria, which comprise the microbiome, are linked to several neurodegenerative disorders. An imbalance in the bacterial population in the gut of Parkinson's disease (PD) and Alzheimer's disease (AD) patients has been detected in several studies. This dysbiosis very likely decreases or increases microbiome-derived molecules that are protective or detrimental, respectively, to the human body and those changes are communicated to the brain through the so-called 'gut-brain-axis'. The microbiome-derived molecule queuine is a hypermodified nucleobase enriched in the brain and is exclusively produced by bacteria and salvaged by humans through their gut epithelium. Queuine replaces guanine at the wobble position (position 34) of tRNAs with GUN anticodons and promotes efficient cytoplasmic and mitochondrial mRNA translation. Queuine depletion leads to protein misfolding and activation of the endoplasmic reticulum stress and unfolded protein response pathways in mice and human cells. Protein aggregation and mitochondrial impairment are often associated with neural dysfunction and neurodegeneration. To elucidate whether queuine could facilitate protein folding and prevent aggregation and mitochondrial defects that lead to proteinopathy, we tested the effect of chemically synthesized queuine, STL-101, in several in vitro models of neurodegeneration. After neurons were pretreated with STL-101 we observed a significant decrease in hyperphosphorylated alpha-synuclein, a marker of alpha-synuclein aggregation in a PD model of synucleinopathy, as well as a decrease in tau hyperphosphorylation in an acute and a chronic model of AD. Additionally, an associated increase in neuronal survival was found in cells pretreated with STL-101 in both AD models as well as in a neurotoxic model of PD. Measurement of queuine in the plasma of 180 neurologically healthy individuals suggests that healthy humans maintain protective levels of queuine. Our work has identified a new role for queuine in neuroprotection uncovering a therapeutic potential for STL-101 in neurological disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Cells, Cultured; Disease Models, Animal; Female; Guanine; Humans; Mice; Neurons; Neuroprotective Agents; Parkinson Disease; Rats, Wistar

α-synuclein (α-syn) aggregation can lead to degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) as invariably observed in patients with Parkinson's Disease (PD). The co-chaperone DNAJB6 has previously been found to be expressed at higher levels in PD patients than in control subjects and was also found in Lewy bodies. Our previous experiments showed that knock out of DNAJB6 induced α-syn aggregation in cellular level. However, effects of overexpression of DNAJB6 against α-syn aggregation remains to be investigated.. We used a α-syn CFP/YFP HEK293 FRET cell line to investigate the effects of overexpression of DNAJB6 in cellular level. α-syn aggregation was induced by transfection α-syn preformed fibrils (PPF), then was measured FRET analysis. We proceeded to investigate if DNAJB6b can impair α-syn aggregation and toxicity in an animal model and used adeno associated vira (AAV6) designed to overexpress of human wt α-syn, GFP-DNAJB6 or GFP in rats. These vectors were injected into the SNpc of the rats, unilaterally. Rats injected with vira to express α-syn along with GFP in the SNpc where compared to rats expressing α-syn and GFP-DNAJB6. We evaluated motor functions, dopaminergic cell death, and axonal degeneration in striatum.. We show that DNAJB6 prevent α-syn aggregation induced by α-syn PFF's, in a cell culture model. In addition, we observed α-syn overexpression caused dopaminergic cell death and that this was strongly reduced by co-expression of DNAJB6b. The lesion caused by α-syn overexpression resulted in behavior deficits, which increased over time as seen in stepping test, which was rescued by co-expression of DNAJB6b.. We here demonstrate for the first time that DNAJB6 is a strong suppressor of α-syn aggregation in cells and in animals and that this results in a suppression of dopaminergic cell death and PD related motor deficits in an animal model of PD.

Topics: alpha-Synuclein; Animals; Axons; Cell Death; Disease Models, Animal; Dopaminergic Neurons; Female; Gene Expression Regulation; HEK293 Cells; HSP40 Heat-Shock Proteins; Humans; Molecular Chaperones; Movement Disorders; Neostriatum; Nerve Tissue Proteins; Parkinson Disease; Psychomotor Performance; Rats; Rats, Sprague-Dawley

With the emergence of disease-modifying therapies for Parkinson's disease, reliable longitudinal markers are needed to quantify pathology and demonstrate disease progression. We developed the A53T-AAV rat model of synucleinopathy by combining longitudinal measures over 12 weeks. We first characterized the progression of the motor and dopaminergic deficits. Then, we monitored the disease progression using the [

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Fluorine Radioisotopes; Male; Motor Activity; Parkinson Disease; Phosphorylation; Positron-Emission Tomography; Protein Aggregates; Rats, Sprague-Dawley; Synucleinopathies; Tyrosine

Parkinson's disease (PD) is a currently incurable neurodegenerative disorder characterized by the loss of dopaminergic (DAergic) neurons in the substantia nigra pars compacta and α-synuclein aggregation. Accumulated evidence indicates that the saponins, especially from ginseng, have neuroprotective effects against neurodegenerative disorders. Interestingly, saponin can also be found in marine organisms such as the sea cucumber, but little is known about its effect in neurodegenerative disease, including PD. In this study, we investigated the anti-Parkinson effects of frondoside A (FA) from

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Apoptosis; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopaminergic Neurons; Gene Expression Regulation; Ginsenosides; Glycosides; Longevity; Nerve Degeneration; Oxidopamine; Parkinson Disease; Proteolysis; Triterpenes

α-Synuclein oligomers are thought to play an important role in the pathogenesis of dementia with Lewy bodies (DLB). There is no effective cure for DLB at present. Previously, we demonstrated that in APP- and tau-transgenic mice, oral or intranasal rifampicin reduced brain Aβ and tau oligomers and improved mouse cognition. In the present study, we expanded our research to DLB. Rifampicin was intranasally administered to 6-month-old A53T-mutant α-synuclein-transgenic mice at 0.1 mg/day for 1 month. The mice displayed memory impairment but no motor deficit at this age, indicating a suitable model of DLB. α-Synuclein pathologies were examined by the immunohistochemical/biochemical analyses of brain tissues. Cognitive function was evaluated by the Morris water maze test. Intranasal rifampicin significantly reduced the levels of [pSer129] α-synuclein in the hippocampus and α-synuclein oligomers in the visual cortex and hippocampus. The level of the presynaptic marker synaptophysin in the hippocampus was recovered to the level in non-transgenic littermates. In the Morris water maze, a significant improvement in spatial reference memory was observed in rifampicin-treated mice. Taken together with our previous findings, these results suggest that intranasal rifampicin is a promising remedy for the prevention of neurodegenerative dementia, including Alzheimer's disease, frontotemporal dementia, and DLB.

Topics: Administration, Intranasal; alpha-Synuclein; Animals; Cognition; Dementia; Disease Models, Animal; Female; Lewy Bodies; Lewy Body Disease; Male; Mice, Transgenic; Protein Multimerization; Rifampin

α-Synuclein is a soluble monomer abundant in the central nervous system. Aggregates of α-synuclein, consisting of higher-level oligomers and insoluble fibrils, have been observed in many chronic neurological diseases and are implicated in neurotoxicity and neurodegeneration. α-Synuclein has recently been shown to aggregate following acute ischemic stroke, exacerbating neuronal damage. Propofol is an intravenous anesthetic that is commonly used during intravascular embolectomy following acute ischemic stroke. While propofol has demonstrated neuroprotective properties following brain injury, the mechanism of protection in the setting of ischemic stroke is unclear. In this study, propofol administration significantly reduced the neurotoxic aggregation of α-synuclein, decreased the infarct area, and attenuated the neurological deficits after ischemic stroke in a mouse model. We then demonstrated that the propofol-induced reduction of α-synuclein aggregation was associated with increased mammalian target of rapamycin/ribosomal protein S6 kinase beta-1 signaling pathway activity and reduction of the excessive autophagy occurring after acute ischemic stroke.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain Infarction; Brain Ischemia; Disease Models, Animal; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Propofol; Psychomotor Performance; Stroke

In Parkinson's disease, some of the first alpha-synuclein aggregates appear in the olfactory system and the dorsal motor nucleus of the vagus nerve before spreading to connected brain regions. We previously demonstrated that injection of alpha-synuclein fibrils unilaterally into the olfactory bulb of wild type mice leads to widespread synucleinopathy in brain regions directly and indirectly connected to the injection site, consistently, over the course of periods longer than 6 months. Our previously reported observations support the idea that alpha-synuclein inclusions propagates between brain region through neuronal networks. In the present study, we further defined the pattern of propagation of alpha-synuclein inclusions and developed a mathematical model based on known mouse brain connectivity. Using this model, we first predicted the pattern of alpha-synuclein inclusions propagation following an injection of fibrils into the olfactory bulb. We then analyzed the fitting of these predictions to our published histological data. Our results demonstrate that the pattern of propagation we observed in vivo is consistent with axonal transport of alpha-synuclein aggregate seeds, followed by transsynaptic transmission. By contrast, simple diffusion of alpha-synuclein fits very poorly our in vivo data. We also found that the spread of alpha-synuclein inclusions appeared to primarily follow neural connections retrogradely until 9 months after injection into the olfactory bulb. Thereafter, the pattern of spreading was consistent with anterograde propagation mathematical models. Finally, we applied our mathematical model to a different, previously published, dataset involving alpha-synuclein fibril injections into the striatum, instead of the olfactory bulb. We found that the mathematical model accurately predicts the reported progressive increase in alpha-synuclein neuropathology also in that paradigm. In conclusion, our findings support that the progressive spread of alpha-synuclein inclusions after injection of protein fibrils follows neural networks in the mouse connectome.

Topics: alpha-Synuclein; Animals; Axonal Transport; Disease Models, Animal; Inclusion Bodies; Mice; Models, Theoretical; Neural Pathways; Neurons; Parkinson Disease

In Parkinson's disease (PD) and related disorders pathological alpha-synuclein has been discussed to propagate via a prion-like mechanism in the CNS. The application of exogenous alpha-synuclein fibrils via injection to animal models of PD has been shown to be a useful method to study prion-like propagation of pathological alpha-synuclein and of transmission pathways that play a critical role in recapitulating characteristics of synucleinopathies. Using bigenic mice expressing mutant human alpha-synuclein in neurons and firefly luciferase in astrocytes we showed that transmission via the tongue and the peritoneum represent entrance points for pathological alpha-synuclein to invade the CNS. Here we present a method to quantify astrogliosis by bioluminescence imaging in an animal model of PD. This method allows noninvasive tracking of the neuroinflammatory process that often precedes neurological signs of disease and represents an alternative to behavioral or histological and biochemical analysis to detect disease.

Topics: alpha-Synuclein; Animals; Biomarkers; Disease Models, Animal; Fluorescent Antibody Technique; Humans; Inflammation; Luminescent Measurements; Mice; Mice, Knockout; Mice, Transgenic; Molecular Imaging; Neurons; Parkinson Disease

Multiple system atrophy (MSA) is a fatal disorder with no effective treatment. MSA pathology is characterized by α-synuclein (aSyn) accumulation in oligodendrocytes, the myelinating glial cells of the central nervous system (CNS). aSyn accumulation in oligodendrocytes forms the pathognomonic glial cytoplasmic inclusions (GCIs) of MSA. MSA aSyn pathology is also associated with motor and autonomic dysfunction, including an impaired ability to sweat. MSA patients have abnormal CNS expression of glial-cell-line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF). Our prior studies using the parent compound FTY720, a food and drug administration (FDA) approved immunosuppressive for multiple sclerosis, reveal that FTY720 protects parkinsonian mice by increasing BDNF. Our FTY720-derivative, FTY720-Mitoxy, is known to increase expression of oligodendrocyte BDNF, GDNF, and nerve growth factor (NGF) but does not reduce levels of circulating lymphocytes as it is not phosphorylated so cannot modulate sphingosine 1 phosphate receptors (S1PRs). To preclinically assess FTY720-Mitoxy for MSA, we used mice expressing human aSyn in oligodendrocytes under a 2,' 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) promoter. CNP-aSyn transgenic (Tg) mice develop motor dysfunction between 7 and 9 mo, and progressive GCI pathology. Using liquid chromatography-mass spectrometry (LC-MS/MS) and enzymatic assays, we confirmed that FTY720-Mitoxy was stable and active. Vehicle or FTY720-Mitoxy (1.1 mg/kg/day) was delivered to wild type (WT) or Tg littermates from 8.5-11.5 mo by osmotic pump. We behaviorally assessed their movement by rotarod and sweat production by starch‑iodine test. Postmortem tissues were evaluated by qPCR for BDNF, GDNF, NGF and GDNF-receptor RET mRNA and for aSyn, BDNF, GDNF, and Iba1 protein by immunoblot. MicroRNAs (miRNAs) were also assessed by qPCR. FTY720-Mitoxy normalized movement, sweat function and soleus muscle mass in 11.5 mo Tg MSA mice. FTY720-Mitoxy also increased levels of brain GDNF and reduced brain miR-96-5p, a miRNA that acts to decrease GDNF expression. Moreover, FTY720-Mitoxy blocked aSyn pathology measured by sequential protein extraction and immunoblot, and microglial activation assessed by immunohistochemistry and immunoblot. In the 3-nitropropionic acid (3NP) toxin model of MSA, FTY720-Mitoxy protected movement and mitochondria in WT and CNP-aSyn Tg littermates. Our data confirm potent in vivo protection by FTY720-

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Female; Fingolimod Hydrochloride; Gene Expression Regulation; Glial Cell Line-Derived Neurotrophic Factor; Humans; Inflammation; Male; Mice; Mice, Transgenic; MicroRNAs; Multiple System Atrophy; Neuroprotective Agents; Proto-Oncogene Proteins c-ret

Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) and the gradual appearance of α-synuclein (α-syn)-containing neuronal protein aggregates. Although the exact mechanism of α-syn-mediated cell death remains elusive, recent research suggests that α-syn-induced alterations in neuronal excitability contribute to cell death in PD. Because the fragile X mental retardation protein (FMRP) controls the expression and function of numerous neuronal genes related to neuronal excitability and synaptic function, we here investigated the role of FMRP in α-syn-associated pathological changes in cell culture and mouse models of PD as well as in post-mortem human brain tissue from PD patients. We found FMRP to be decreased in cultured DA neurons and in the mouse brain in response to α-syn overexpression. FMRP was, furthermore, lost in the SNc of PD patients and in patients with early stages of incidental Lewy body disease (iLBD). Unlike fragile X syndrome (FXS), FMR1 expression in response to α-syn was regulated by a mechanism involving Protein Kinase C (PKC) and cAMP response element-binding protein (CREB). Reminiscent of FXS neurons, α-syn-overexpressing cells exhibited an increase in membrane N-type calcium channels, increased phosphorylation of ERK1/2, eIF4E and S6, increased overall protein synthesis, and increased expression of Matrix Metalloproteinase 9 (MMP9). FMRP affected neuronal function in a PD animal model, because FMRP-KO mice were resistant to the effect of α-syn on striatal dopamine release. In summary, our results thus reveal a new role of FMRP in PD and support the examination of FMRP-regulated genes in PD disease progression.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Cell Culture Techniques; Disease Models, Animal; Female; Fragile X Mental Retardation Protein; Humans; Male; Mice; Middle Aged; Parkinson Disease; Phenotype

Parkinson's disease is one of the most common movement disorders and is characterized by dopaminergic cell loss and the accumulation of pathological α-synuclein, but its precise pathogenetic mechanisms remain elusive. To develop disease-modifying therapies for Parkinson's disease, an animal model that recapitulates the pathology and symptoms of the disease, especially in the prodromal stage, is indispensable. As subjects with α-synuclein gene (SNCA) multiplication as well as point mutations develop familial Parkinson's disease and a genome-wide association study in Parkinson's disease has identified SNCA as a risk gene for Parkinson's disease, the increased expression of α-synuclein is closely associated with the aetiology of Parkinson's disease. In this study we generated bacterial artificial chromosome transgenic mice harbouring SNCA and its gene expression regulatory regions in order to maintain the native expression pattern of α-synuclein. Furthermore, to enhance the pathological properties of α-synuclein, we inserted into SNCA an A53T mutation, two single-nucleotide polymorphisms identified in a genome-wide association study in Parkinson's disease and a Rep1 polymorphism, all of which are causal of familial Parkinson's disease or increase the risk of sporadic Parkinson's disease. These A53T SNCA bacterial artificial chromosome transgenic mice showed an expression pattern of human α-synuclein very similar to that of endogenous mouse α-synuclein. They expressed truncated, oligomeric and proteinase K-resistant phosphorylated forms of α-synuclein in the regions that are specifically affected in Parkinson's disease and/or dementia with Lewy bodies, including the olfactory bulb, cerebral cortex, striatum and substantia nigra. Surprisingly, these mice exhibited rapid eye movement (REM) sleep without atonia, which is a key feature of REM sleep behaviour disorder, at as early as 5 months of age. Consistent with this observation, the REM sleep-regulating neuronal populations in the lower brainstem, including the sublaterodorsal tegmental nucleus, nuclei in the ventromedial medullary reticular formation and the pedunculopontine nuclei, expressed phosphorylated α-synuclein. In addition, they also showed hyposmia at 9 months of age, which is consistent with the significant accumulation of phosphorylated α-synuclein in the olfactory bulb. The dopaminergic neurons in the substantia nigra pars compacta degenerated, and their number was decreased in an age-dependent

Topics: alpha-Synuclein; Animals; Brain; Cell Count; Chromosomes, Artificial, Bacterial; Disease Models, Animal; Electroencephalography; Electromyography; Endopeptidase K; Mice; Mice, Transgenic; Olfaction Disorders; Parkinson Disease; Polymorphism, Single Nucleotide; Prodromal Symptoms; REM Sleep Behavior Disorder; Sleep

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by loss of dopaminergic neurons in substantia nigra region and the presence of α-synuclein aggregates in the striatum and surrounding areas of brain. Evidences suggest that neuroinflammation plays a role in the progression of PD. We examined the neuro-protective effects of Bacopa monnieri (BM) in regulating neuroinflammation. Administration of BM suppressed the level of pro-inflammatory cytokines, decreased the levels of α-synuclein, and reduced reactive oxygen species (ROS) generation in PD animal model. Pre-treatment of BM showed more prominent results as compare to co- and post-treatment. Results suggest that Bacopa can limit inflammation in the different areas of brain, thus, offers a promising source of novel therapeutics for the treatment of many CNS disorders.

Topics: alpha-Synuclein; Animals; Bacopa; Cerebral Cortex; Chemokine CCL4; Disease Models, Animal; Hippocampus; Interleukin-1beta; Interleukin-6; Male; Neuroprotective Agents; Oxidative Stress; Parkinson Disease, Secondary; Plant Extracts; Rats; Rats, Wistar; Reactive Oxygen Species; Rotenone; Substantia Nigra; Tumor Necrosis Factor-alpha

Synucleinopathies are conditions that remain with no available effective treatments thus far. Immunotherapy is a possible path to fight against such pathologies by inducing antibodies against alpha-synuclein (α-Syn), which could induce the clearance of its pathologic form. Looking to develop a new low-cost, effective vaccine against synucleinopathies; we have designed a chimeric plant-made antigen comprising the subunit B of the enterotoxin from enterotoxigenic E. coli and three B cell epitopes from α-Syn, which is named LTB-Syn. In the present study, LTB-Syn was produced in carrot cell lines as appropriate platform for the formulation of oral vaccines not requiring purification. The development of transgenic carrot cell lines took 8 months and the LTB-Syn yield reached 2.3 μg/g dry biomass. The antigen encapsulated in lyophilized carrot cells was highly stable at room temperature over a six-month period and upon heating at 50 °C for 2 h. Moreover, LTB-Syn was able to prime immune responses that, in combination with parenteral boosting using an OVA-Syn conjugate, induced significant humoral resposes in mice. Thus the carrot-made oral LTB-Syn vaccine is a promising candidate that deserves further analyses to advance in its preclinical evaluation.

Topics: alpha-Synuclein; Animals; Biomass; Cell Line; Daucus carota; Disease Models, Animal; Enterotoxins; Epitopes, B-Lymphocyte; Escherichia coli; Escherichia coli Proteins; Female; Immunogenicity, Vaccine; Immunotherapy; Mice; Mice, Inbred BALB C; Plants, Genetically Modified; Synucleinopathies; Vaccines

Progression through neuronal loss of substantia nigra pars compacta (SNpc) with Parkinson's disease depends on various protein post-translational modifications mainly comprising ubiquitination. Although many ubiquitination sites have been identified through site-specific methods, systematic quantitative proteomic analysis of pre-symptomatic Parkinson's disease remains unexplored. Using quantitative proteomics, we have globally profiled ubiquitination in SNpc tissue of a Parkinson's disease transgenic mouse model (A30P*A53 T α-synuclein, hm

Topics: alpha-Synuclein; Animals; Computational Biology; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; Pars Compacta; Proteomics; Ubiquitinated Proteins; Ubiquitination

There is increasing evidence that widespread cortical cerebral blood flow deficits occur early in the course of Parkinson's disease. Although cerebral blood flow measurement has been suggested as a potential biomarker for early diagnosis of Parkinson's disease, as well as a means for tracking response to treatment, the relationship of cerebral blood flow to α-synucleinopathy, a major pathological hallmark of Parkinson's disease, remains unclear. Therefore, we performed arterial spin-labeling magnetic resonance imaging and diffusion tensor imaging on transgenic mice overexpressing human wild-type α-synuclein and age-matched controls to measure cerebral blood flow and degenerative changes. As reported for early-stage Parkinson's disease, α-synuclein mice exhibited a significant reduction in cortical cerebral blood flow, which was accompanied by motor coordination deficits and olfactory dysfunction. Although no overt degenerative changes were apparent in diffusion tensor imaging images, magnetic resonance imaging volumetric analysis revealed a significant reduction in olfactory bulb volume, similar to that seen in Parkinson's disease patients. Our data, representing the first report of cerebral blood flow deficit in an animal model of Parkinson's disease, suggest a causative role for α-synucleinopathy in cerebral blood flow deficits in Parkinson's disease. Thus, α-synuclein transgenic mice comprise a promising model to study Parkinson's disease-related mechanisms of cerebral blood flow deficits and to investigate further its utility as a potential biomarker for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Brain; Case-Control Studies; Cerebrovascular Circulation; Diffusion Tensor Imaging; Disease Models, Animal; Dopamine; Magnetic Resonance Imaging; Male; Mice; Mice, Transgenic; Olfaction Disorders; Olfactory Bulb; Parkinson Disease; Synucleinopathies

Neuroprotective properties of fullerenols С

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Drosophila melanogaster; Fullerenes; Humans; Neuroprotective Agents; Oxidative Stress; Parkinson Disease

Parkinson's disease, a progressive neurodegenerative disease, is caused by the loss of dopaminergic neurons in the substantia nigra (SN). It is characterized by the formation of intracytoplasmic Lewy bodies that are primarily composed of the protein alpha-synuclein (α-syn), along with dystrophic neurites. Acupuncture stimulation results in an enhanced survival of dopaminergic neurons in the SN in Parkinsonism animal models. We investigated the role of acupuncture in inhibiting the increase in α-syn expression that is related to dopaminergic cell loss in the SN in a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) Parkinsonism mouse model. In this model, acupuncture stimulation at GB34 and LR3 attenuated the decrease in tyrosine hydroxylase in the SN. Moreover, acupuncture stimulation attenuated the increase in α-syn in SN. Acupuncture stimulation also maintained the phosphorylated α-syn on serine 129 at levels similar to the control group. Our findings indicate that the MPTP-mediated increase in α-syn, and the acupuncture-mediated inhibition of the increase in α-syn, may be responsible for the neuroprotective effects of acupuncture in the SN following damage induced by MPTP.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Acupuncture Therapy; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinsonian Disorders; Substantia Nigra; Tyrosine 3-Monooxygenase

The pathological hallmark of synucleinopathies, including Lewy body dementia and Parkinson's disease (PD), is the presence of Lewy bodies, which are primarily composed of intracellular inclusions of misfolded α-synuclein (α-syn) among other proteins. α-Syn is found in extracellular biological fluids in PD patients and has been implicated in modulating immune responses in the central nervous system (CNS) and the periphery. Natural killer (NK) cells are innate effector lymphocytes that are present in the CNS in homeostatic and pathological conditions. NK cell numbers are increased in the blood of PD patients and their activity is associated with disease severity; however, the role of NK cells in the context of α-synucleinopathies has never been explored. Here, we show that human NK cells can efficiently internalize and degrade α-syn aggregates via the endosomal/lysosomal pathway. We demonstrate that α-syn aggregates attenuate NK cell cytotoxicity in a dose-dependent manner and decrease the release of the proinflammatory cytokine, IFN-γ. To address the role of NK cells in PD pathogenesis, NK cell function was investigated in a preformed fibril α-syn-induced mouse PD model. Our studies demonstrate that in vivo depletion of NK cells in a preclinical mouse PD model resulted in exacerbated motor deficits and increased phosphorylated α-syn deposits. Collectively, our data provide a role of NK cells in modulating synuclein pathology and motor symptoms in a preclinical mouse model of PD, which could be developed into a therapeutic for PD and other synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Central Nervous System; Cytokines; Disease Models, Animal; Female; Killer Cells, Natural; Lewy Bodies; Lewy Body Disease; Lysosomes; Male; Mice; Mice, Transgenic; Parkinson Disease; Synucleinopathies; Synucleins

Topics: alpha-Synuclein; Animals; Autophagy; Brain; Clinical Trials as Topic; Disease Models, Animal; Humans; Inflammation; Mice; Parkinson Disease; Protein Aggregates; Pyridones; Pyrimidines

Pre-clinical studies in models of multiple sclerosis and other inflammatory disorders suggest that high-salt diet may induce activation of the immune system and potentiate inflammation. However, high-salt diet constitutes a common non-pharmacological intervention to treat autonomic problems in synucleinopathies such as Parkinson's disease and multiple system atrophy. Since neuroinflammation plays an important pathogenic role in these neurodegenerative disorders, we asked here whether high-salt diet may aggravate the disease phenotype in a transgenic model of multiple system atrophy.. Nine-month-old PLP-hαSyn and matched wildtype mice received normal or high-salt diet for a period of 3 months. Behavioral, histological, and molecular analyses were performed to evaluate the effect of high-salt diet on motor decline, neuroinflammation, neurodegeneration, and α-synuclein accumulation in these mice.. Brain subregion-specific molecular and histological analyses showed no deleterious effects of high-salt diet on the level of microglial activation. Moreover, neuroinflammation-related cytokines and chemokines, T cell recruitment or astrogliosis were unaffected by high-salt diet exposure. Behavioral testing showed no effect of diet on motor decline. High-salt diet was not related to the deterioration of neurodegeneration or α-synuclein accumulation in PLP-hαSyn mice.. Here, we demonstrate that high-salt diet does not aggravate neuroinflammation and neurodegeneration in PLP-hαSyn mice. Our findings discard a deleterious pro-neuroinflammatory effect of high-salt diet in multiple system atrophy.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Inflammation; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Multiple System Atrophy; Nerve Degeneration; Neurons; Sodium Chloride, Dietary

Parkinson's disease (PD) is a multifactorial malady and the second most common neurodegenerative disorder, characterized by loss of dopaminergic neurons in the midbrain. A hallmark of PD pathology is the formation of intracellular protein inclusions, termed Lewy bodies (LBs). Recent MS studies have shown that OTU deubiquitinase ubiquitin aldehyde-binding 1 (OTUB1), a deubiquitinating enzyme of the OTU family, is enriched together with α-synuclein in LBs from individuals with PD and is also present in amyloid plaques associated with Alzheimer's disease. In the present study, using mammalian cell cultures and a PD mouse model, along with CD spectroscopy, atomic force microscopy, immunofluorescence-based imaging, and various biochemical assays, we demonstrate that after heat-induced protein aggregation, OTUB1 reacts strongly with both anti-A11 and anti-osteocalcin antibodies, detecting oligomeric, prefibrillar structures or fibrillar species of amyloidogenic proteins, respectively. Further, recombinant OTUB1 exhibited high thioflavin-T and Congo red binding and increased β-sheet formation upon heat induction. The oligomeric OTUB1 aggregates were highly cytotoxic, characteristic of many amyloid proteins. OTUB1 formed inclusions in neuronal cells and co-localized with thioflavin S and with α-synuclein during rotenone-induced stress. It also co-localized with the disease-associated variant pS129-α-synuclein in rotenone-exposed mouse brains. Interestingly, OTUB1 aggregates were also associated with severe cytoskeleton damage, rapid internalization inside the neuronal cells, and mitochondrial damage, all of which contribute to neurotoxicity. In conclusion, the results of our study indicate that OTUB1 may contribute to LB pathology through its amyloidogenic properties.

Topics: Actin Cytoskeleton; alpha-Synuclein; Amyloid; Animals; Apoptosis; Cell Death; Cell Line, Tumor; Computer Simulation; Cytoskeleton; Deubiquitinating Enzymes; Disease Models, Animal; Endocytosis; Male; Mice, Inbred C57BL; Mitochondria; Models, Biological; Nanostructures; Neurons; Neurotoxins; Oxidation-Reduction; Parkinson Disease; Phosphoserine; Protein Aggregates; Protein Multimerization; Reactive Oxygen Species; Rotenone

RT-QuIC is a shaking-based cyclic amplification technique originally developed in the prion field to detect minute amounts of scrapie prion protein (PrP

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Animals; Biological Assay; Brain; Disease Models, Animal; Humans; Lewy Body Disease; Mice, Transgenic; Middle Aged; Mutation; Synucleinopathies

α-Synucleinopathies are characterized by autonomic dysfunction and motor impairments. In the pure autonomic failure (PAF), α-synuclein (α-Syn) pathology is confined within the autonomic nervous system with no motor features, but mouse models recapitulating PAF without motor dysfunction are lacking. Here, we show that in TgM83

Topics: alpha-Synuclein; Animals; Behavior Observation Techniques; Disease Models, Animal; Ganglia, Autonomic; Humans; Male; Mice; Mice, Transgenic; Mutation; Protein Aggregates; Pure Autonomic Failure; Synucleinopathies

Dementia with Lewy bodies (DLB) represents a huge medical need as it accounts for up to 30% of all dementia cases, and there is no cure available. The underyling spectrum of pathology is complex and creates a challenge for targeted molecular therapies. We here tested the hypothesis that leukotrienes are involved in the pathology of DLB and that blocking leukotrienes through Montelukast, a leukotriene receptor antagonist and approved anti-asthmatic drug, might alleviate pathology and restore cognitive functions. Expression of 5-lipoxygenase, the rate-limiting enzyme for leukotriene production, was indeed elevated in brains with DLB. Treatment of cognitively deficient human alpha-synuclein overexpressing transgenic mice with Montelukast restored memory. Montelukast treatment resulted in modulation of beclin-1 expression, a marker for autophagy, and in a reduction in the human alpha-synulcein load in the transgenic mice. Reducing the protein aggregation load in neurodegenerative diseases might be a novel model of action of Montelukast. Moreover, this work presents leukotriene signaling as a potential drug target for DLB and shows that Montelukast might be a promising drug candidate for future DLB therapy development.

Topics: Acetates; alpha-Synuclein; Animals; Cyclopropanes; Disease Models, Animal; Female; Humans; Leukotriene Antagonists; Lewy Body Disease; Memory; Memory Disorders; Mice; Mice, Transgenic; Quinolines; Receptors, Leukotriene; Sulfides

Improved analytical tools for detailed characterization of synucleins in pre-clinical models of Parkinson's disease (PD) and related synucleinopathies are needed.. Develop a multiple reaction monitoring (MRM) liquid chromatography tandem mass spectrometry (LC-MS/MS) assay to quantify species-specific sequences and structural heterogeneity in soluble α- and β-synucleins in brain tissue.. Using a proteolytic digestion workflow, the MRM LC-MS/MS method assayed six proteotypic peptides from the α-synuclein sequence; three unique to mouse or human α-synuclein and three conserved in α- and β-synuclein. For quantification, we used labeled α-synuclein as the internal standard and an external calibration curve. As proof of concept, the synuclein LC-MS/MS method was applied to brain tissue specimens from M83 transgenic PD mice, which overexpresses human α-synuclein, relative to wild-type littermate controls.. The synuclein MRM assay was linear over a wide concentration range (at least one order of magnitude). The assay had several advantages over ligand binding analytical methods, such as western blotting and enzyme-linked immunosorbent assays. These advantages included the ability to: quantify 1) total α-synuclein, 2) combined α- and β-synucleins, 3) species-specific contributions to total α-synuclein (e.g., in mice expressing both mouse and human α-synuclein), and 4) identify peptide-specific profile differences that may reflect post-translational modifications, all within a single analysis.. With improved and expanded analytical characteristics coupled with a streamlined sample preparation workflow, the quantitative synuclein profiling LC-MS/MS assay provides a versatile and efficient platform to characterize synuclein biology in pre-clinical models and the potential for application to human tissues and fluids.

Topics: alpha-Synuclein; Animals; beta-Synuclein; Biological Assay; Brain; Chromatography, Liquid; Disease Models, Animal; Mice, Transgenic; Parkinson Disease; Peptide Hydrolases; Proof of Concept Study; Species Specificity; Tandem Mass Spectrometry

Rotigotine, a non-ergoline dopamine agonist, has been shown to be highly effective for the treatment of Parkinson's disease (PD). However, despite its therapeutic potential, its' clinical applications were hindered due to low aqueous solubility, first-pass metabolism and low bioavailability. Therefore, we developed rotigotine-loaded chitosan nanoparticles (RNPs) for nose-to-brain delivery and evaluated its neuronal uptake, antioxidant and neuroprotective effects using cell-based studies. The pharmacological effects of nose-to-brain delivery of the RNPs were also evaluated in an animal model of PD. The average particle size, particle size distribution and entrapment efficiency of the RNPs were found to be satisfactory. Exposure of RNPs for 24 h did not show any cytotoxicity towards SH-SY5Y human neuroblastoma cells. Furthermore, the RNPs caused a decrease in alpha-synuclein (SNCA) and an increase in tyrosine hydroxylase (TH) expression in these cells, suggestion that the exposure alleviated some of the direct neurotoxic effects of 6-OHDA. Behavioral and biochemical testing of RNPs in haloperidol-induced PD rats showed a reversal of catalepsy, akinesia and restoration of swimming ability. A decrease in lactate dehydrogenase (LDH) and an increase in catalase activities were also observed in the brain tissues. The results from the animal model of PD show that intranasally-administered RNPs enhanced brain targeting efficiency and drug bioavailability. Thus, RNPs for nose-to-brain delivery has significant potential to be developed as a treatment approach for PD.

Topics: Administration, Intranasal; alpha-Synuclein; Animals; Blood-Brain Barrier; Cell Line, Tumor; Chitosan; Disease Models, Animal; Dopamine Agonists; Drug Carriers; Female; Haloperidol; Humans; Male; Nanoparticles; Neurons; Oxidopamine; Parkinson Disease, Secondary; Particle Size; Rats; Tetrahydronaphthalenes; Thiophenes; Toxicity Tests, Acute

The main symptom of Parkinson's disease (PD) is motor dysfunction and remarkably approximately 30-40% of PD patients exhibit cognitive impairments. Recently, we have developed MF8, a heart-type fatty acid-binding protein (FABP3)-specific ligand, which can inhibit α-synuclein (α-syn) oligomerization induced by arachidonic acid in FABP3 overexpressing neuro2A cells. The present study aimed to determine whether MF8 attenuates dopaminergic neuronal death and motor and cognitive impairments in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice model. MF8 can penetrate the blood-brain barrier and its peak brain concentration (21.5 ± 2.1 nM) was achieved 6 h after the oral administration (1.0 mg/kg). We also compared its effects and pharmacological action with those of L-DOPA (3,4-dihydroxy-l-phenylalanine). PD model mice were developed by administering MPTP (25 mg/kg, i.p.) once a day for five consecutive days. Twenty-four hours after the final MPTP injection, mice were administered MF8 (0.3, 1.0 mg/kg, p.o.) or L-DOPA (25 mg/kg, i.p.) once a day for 28 consecutive days and subjected to behavioral and histochemical studies. MF8 (1.0 mg/kg, p.o.), but not L-DOPA, inhibited the dopaminergic neuronal death in the ventral tegmental area and the substantia nigra pars compacta region of the MPTP-treated mice. MF8 also improved both, motor and cognitive functions, while L-DOPA ameliorated only motor dysfunction. Taken together, our results showed that MF8 attenuated the MPTP-induced dopaminergic neuronal death associated with PD pathology. We present MF8 as a novel disease-modifying therapeutic molecule for PD, which acts via a mechanism different from that of L-DOPA.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antiparkinson Agents; Blood-Brain Barrier; Cell Death; Cognitive Dysfunction; Disease Models, Animal; Dopaminergic Neurons; Fatty Acid Binding Protein 3; Levodopa; Ligands; Male; Mice; Mice, Inbred C57BL; Motor Activity; Neuroprotective Agents; Parkinson Disease; Protein Aggregation, Pathological

Aggregation of human α-synuclein (αSyn) is linked to Parkinson's disease (PD) pathology. The central region of the αSyn sequence contains the non-amyloid β-component (NAC) crucial for aggregation. However, how NAC flanking regions modulate αSyn aggregation remains unclear. Using bioinformatics, mutation and NMR, we identify a 7-residue sequence, named P1 (residues 36-42), that controls αSyn aggregation. Deletion or substitution of this 'master controller' prevents aggregation at pH 7.5 in vitro. At lower pH, P1 synergises with a sequence containing the preNAC region (P2, residues 45-57) to prevent aggregation. Deleting P1 (ΔP1) or both P1 and P2 (ΔΔ) also prevents age-dependent αSyn aggregation and toxicity in C. elegans models and prevents αSyn-mediated vesicle fusion by altering the conformational properties of the protein when lipid bound. The results highlight the importance of a master-controller sequence motif that controls both αSyn aggregation and function-a region that could be targeted to prevent aggregation in disease.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Bacterial Proteins; Caenorhabditis elegans; Cloning, Molecular; Disease Models, Animal; Escherichia coli; Gene Expression; Genes, Reporter; Genetic Vectors; Humans; Hydrogen-Ion Concentration; Luminescent Proteins; Neurons; Parkinson Disease; Phosphatidylserines; Protein Aggregates; Protein Multimerization; Proteolipids; Recombinant Proteins; Sequence Alignment

Microglia maintain brain homeostasis by removing neuron-derived components such as myelin and cell debris. The evidence linking microglia to neurodegenerative diseases is growing; however, the precise mechanisms remain poorly understood. Herein, we report a neuroprotective role for microglia in the clearance of neuron-released α-synuclein. Neuronal α-synuclein activates microglia, which in turn engulf α-synuclein into autophagosomes for degradation via selective autophagy (termed synucleinphagy). Synucleinphagy requires the presence of microglial Toll-like receptor 4 (TLR4), which induces transcriptional upregulation of p62/SQSTM1 through the NF-κB signaling pathway. Induction of p62, an autophagy receptor, is necessary for the formation of α-synuclein/ubiquitin-positive puncta that are degraded by autophagy. Finally, disruption of microglial autophagy in mice expressing human α-synuclein promotes the accumulation of misfolded α-synuclein and causes midbrain dopaminergic neuron degeneration. Our study thus identifies a neuroprotective function of microglia in the clearance of α-synuclein via TLR4-NF-κB-p62 mediated synucleinphagy.

Topics: alpha-Synuclein; Animals; Autoantigens; Autophagy; Brain; Disease Models, Animal; Dopaminergic Neurons; Female; HEK293 Cells; Humans; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Neurodegenerative Diseases; NF-kappa B; Signal Transduction; Toll-Like Receptor 4

Accumulation of α-synuclein (αSyn) in the dopaminergic neurons is a common pathology seen in patients with Parkinson's disease (PD). Overproduction of αSyn potentiates the formation of oligomeric αSyn aggregates and enhances dopaminergic neuron degeneration. Downregulating intracellular monomeric αSyn prevents the formation of αSyn oligomers and is a potential therapeutic strategy to attenuate the progression of PD.. The purpose of this study is to investigate the efficacy of gene delivery of αSyn-specific single-chain antibodies in vitro and in vivo.. The plasmids for αSyn and selective antibodies (NAC32, D10, and VH14) were constructed and were transfected to HEK293 and SH-SY5Y cells. Co-expression of αSyn with NAC32, but not D10 or VH14, profoundly downregulated αSyn protein, but not αSyn mRNA levels in these cells. The interaction of αSyn and NAC32 antibody was next examined in vivo. Adeno-associated virus (AAV)-αSyn combined with AAV-NAC32 or AAV-sc6H4 (a negative control virus) were stereotactically injected into the substantia nigra of adult rats. AAV-NAC32 significantly reduced AAV-encoded αSyn levels in the substantia nigra and striatum and increased tyrosine hydroxylase immunoreactivity in the striatum. Also, in the animals injected with AAV-NAC32 alone, endogenous αSyn protein levels were significantly downregulated in the substantia nigra.. Our data suggest that AAV-mediated gene transfer of NAC32 is a feasible approach for reducing the expression of target αSyn protein in brain.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Corpus Striatum; Dependovirus; Disease Models, Animal; Down-Regulation; Gene Transfer Techniques; HEK293 Cells; Humans; Parkinson Disease; Rats; Single-Chain Antibodies; Substantia Nigra

Although the malfunction of HtrA2/Omi leads to Parkinson's disease (PD), the underlying mechanism has remained unknown. Here, we showed that HtrA2/Omi specifically removed oligomeric α-Syn but not monomeric α-Syn to protect oligomeric α-Syn-induced neurodegeneration. Experiments using mnd2 mice indicated that HtrA2/Omi degraded oligomeric α-Syn specifically without affecting monomers. Transgenic Drosophila melanogaster experiments of the co-expression α-Syn and HtrA2/Omi and expression of genes individually also confirmed that pan-neuronal expression of HtrA2/Omi completely rescued Parkinsonism in the α-Syn-induced PD Drosophila model by specifically removing oligomeric α-Syn. HtrA2/Omi maintained the health and integrity of the brain and extended the life span of transgenic flies. Because HtrA2/Omi specifically degraded oligomeric α-Syn, co-expression of HtrA2/Omi and α-Syn in Drosophila eye maintained a healthy retina, while the expression of α-Syn induced retinal degeneration. This work showed that the bacterial function of HtrA to degrade toxic misfolded proteins is evolutionarily conserved in mammalian brains as HtrA2/Omi.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Drosophila melanogaster; Female; High-Temperature Requirement A Serine Peptidase 2; Humans; Male; Mice; Mice, Inbred C57BL; Neurons; Parkinson Disease

The etiology and pathogenesis of Parkinson's disease (PD) are tightly linked to the gain-of-function of α-synuclein. However, gradual accumulation of α-synuclein aggregates in dopaminergic neurons of substantia nigra pars compacta (SNpc) leads to the depletion of the functional pool of soluble α-synuclein, and therefore, creates loss-of-function conditions, particularly in presynaptic terminals of these neurons. Studies of how this late-onset depletion of a protein involved in many important steps of neurotransmission contributes to PD progression and particularly, to worsening the nigrostriatal pathology at late stages of the disease are limited and obtained data, are controversial. Recently, we produced a mouse line for conditional knockout of the gene encoding α-synuclein, and here we used its tamoxifen-inducible pan-neuronal inactivation to study consequences of the adult-onset (from the age of 6 months) and late-onset (from the age of 12 months) α-synuclein depletion to the nigrostriatal system. No significant changes of animal balance/coordination, the number of dopaminergic neurons in the SNpc and the content of dopamine and its metabolites in the striatum were observed after adult-onset α-synuclein depletion, but in aging (18-month-old) late-onset depleted mice we found a significant reduction of major dopamine metabolites without changes to the content of dopamine itself. Our data suggest that this might be caused, at least partially, by reduced expression of aldehyde dehydrogenase ALDH1a1 and could lead to the accumulation of toxic intermediates of dopamine catabolism. By extrapolating our findings to a potential clinical situation, we suggest that therapeutic downregulation of α-synuclein expression in PD patients is a generally safe option as it should not cause adverse side effects on the functionality of their nigrostriatal system. However, if started in aged patients, this type of therapy might trigger slight functional changes of the nigrostriatal system with potentially unwanted additive effect to already existing pathology.

Topics: Aging; Aldehyde Dehydrogenase 1 Family; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Down-Regulation; Gene Expression; Gene Knockout Techniques; Mice, Inbred C57BL; Mice, Knockout; Molecular Targeted Therapy; Parkinson Disease; Retinal Dehydrogenase; Substantia Nigra; Synaptic Transmission

Tianma Gouteng granules (TG), a clinical prescription of traditional Chinese medicine, has been clinically applied to treat Parkinson's disease (PD) in combination with Madopar, as included in the Chinese Pharmacopoeia (2015). TG has the potential to decrease the susceptibility of PD pharmacologically, however the mechanisms need detailed demonstration.. To evaluate the pharmacological activities, as well as the possible mechanism of TG in diverse models of PD.. 6-OHDA-treated rats, MPTP-treated mice, and α-synuclein A53T overexpressed mice, were utilized as PD animal models. Rotarod, locomotor activity, inclined plane and traction tests were used for behavioral assessment. Immunohistochemistry was used for tyrosine hydrolase determination. Western blot were conducted for detection of 4-HNE and 15-lipoxygenase-1 (ALOX15). The interactions of ALOX15 with the components in TG were predicted by molecular docking approach.. Lipid peroxidation was involved in dopaminergic neuron damage in 6-OHDA-induced rat models. In MPTP-treated mice, the inhibition of lipid peroxidation improved behavioral and pathological symptoms of PD. The lipid peroxidation-related protein, ALOX15 was found to be the key factor in PD process in diverse PD models including 6-OHDA-treated rats, MPTP-treated mice, and α-synuclein A53T overexpressed mice. TG treatment significantly relieved behavioral and pathological symptoms of MPTP-induced PD mouse models with a potential mechanism of alleviating ALOX15-induced lipid peroxidation. Moreover, the results of molecular docking analysis show that compounds in TG might have interactions with ALOX15.. TG effectively improved the behavioral and dopaminergic neuron damage in diverse PD models. The mechanism of this action may be related to the direct inhibition of ALOX15 and the relief of lipid peroxidation.

Topics: alpha-Synuclein; Animals; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Disease Models, Animal; Drugs, Chinese Herbal; Lipid Peroxidation; Male; Medicine, Chinese Traditional; Mice; Mice, Inbred C57BL; Molecular Docking Simulation; Neuroprotective Agents; Parkinson Disease; Rats; Rats, Sprague-Dawley; Substantia Nigra

Numerous studies highlighted the beneficial effects of the Mediterranean diet (MD) in maintaining health, especially during ageing. Even neurodegeneration, which is part of the natural ageing process, as well as the foundation of ageing-related neurodegenerative disorders like Alzheimer's and Parkinson's disease (PD), was successfully targeted by MD. In this regard, olive oil and its polyphenolic constituents have received increasing attention in the last years. Thus, this study focuses on two main olive oil polyphenols, hydroxytyrosol (HT) and oleuropein aglycone (OLE), and their effects on ageing symptoms with special attention to PD. In order to avoid long-lasting, expensive, and ethically controversial experiments, the established invertebrate model organism

Topics: Acetates; alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Cyclopentane Monoterpenes; Disease Models, Animal; Dopaminergic Neurons; Parkinson Disease; Phenylethyl Alcohol; Polyphenols; Pyrans; Treatment Outcome

The α-Synuclein (α-syn) and tau have synergistic effects on neurodegenerative diseases induced by environmental factors or genetic mutation. Thus, we investigated the role of α-syn and tau in neurodegeneration induced by chronic methamphetamine (METH) exposure (1.0∼20.0 mg/kg/d body weight, for 14 consecutive days). Here, we present a mice model with evidences of α-syn and tau participating in toxicology in chronic METH. METH increased α-syn level in the stratum oriens, pyramidal layer, stratum radiatum and stratum moleculare of hippocampal CA1, CA2 and CA3, polymorph layer of hippocampal dentate gyrus (DG), and substantia nigra (SN). The subcellular locations of the upregulated α-syn were mainly found in mitochondria and axons. The METH upregulated α-syn may directly induce mitochondrial damage, myelin sheath destruction, and synaptic failure. Also, the excess α-syn might indirectly promote tau phosphorylation through tau kinase GSK3β and CDK5, leading to microtubule depolymerization and eventually fusion deficit of autophagosome and lysosome. In the in vitro experiment, the autophagic vacuoles failed to fuse with the lysosome. The neuropathology induced by both the direct and indirect effects of α-syn could be alleviated by α-syn knockout. Taking together, these results indicate that the α-syn mediates the neurodegenerative process induced by chronic METH and that reducing α-syn might be a potential approach to protect the toxic effects of METH and also be, to a broader view, of therapeutic value in neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Autophagy; Axons; Cells, Cultured; Cyclin-Dependent Kinase 5; Disease Models, Animal; Glycogen Synthase Kinase 3 beta; Hippocampus; Lysosomes; Male; Methamphetamine; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; Nerve Degeneration; Neurons; Neurotoxicity Syndromes; Phosphorylation; Substantia Nigra; tau Proteins; Time Factors

The spreading and accumulation of α-synuclein and dopaminergic neurodegeneration, two hallmarks of Parkinson's disease (PD), have been faithfully reproduced in rodent brains by chronic, oral administration of β-sitosterol β-D-glucoside (BSSG). We investigated whether a single injection of BSSG (6 μg BSSG/μL DMSO) in the left substantia nigra of Wistar rats causes the same effects. Mock DMSO injections and untreated rats formed control groups. We performed immunostainings against the pathological α-synuclein, the dopaminergic marker tyrosine hydroxylase (TH), the neuroskeleton marker β-III tubulin, the neurotensin receptor type 1 (NTSR1) as non-dopaminergic phenotype marker and Fluro-Jade C (F-J C) label for neurodegeneration. Using β-galactosidase (β-Gal) assay and active caspase-3 immunostaining, we assessed cell death mechanisms. Golgi-Cox staining was used to measure the density and types of dendritic spines of striatal medium spiny neurons. Motor and non-motor alterations were also evaluated. The study period comprised 15 to 120 days after the lesion. In the injured substantia nigra, BSSG caused a progressive α-synuclein aggregation and dopaminergic neurodegeneration caused by senescence and apoptosis. The α-synuclein immunoreactivity was also present within microglia cells. Decreased density of dopaminergic fibers and dendritic spines also occurred in the striatum. Remarkably, all the histopathological changes also appeared on the contralateral nigrostriatal system, and α-synuclein aggregates were present in other brain regions. Motor and non-motor behavioral alterations were progressive. Our data show that the stereotaxic BSSG administration reproduces PD α-synucleinopathy phenotype in the rat. This approach will aid in identifying the spread mechanism of α-synuclein pathology and validate anti-synucleinopathy therapies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Injections, Intraventricular; Nerve Degeneration; Parkinson Disease; Rats; Rats, Wistar; Sitosterols; Substantia Nigra

Stress-induced α-synuclein aggregation, especially the most toxic species (oligomers), may precede synaptic and cognitive dysfunction. Under pathological conditions, α-synuclein is degraded primarily through the autophagic/lysosomal pathway. We assessed the involvement of autophagy in α-synuclein aggregation and cognitive impairment following general anesthesia and surgical stress. Autophagy was found to be suppressed in the aged rat hippocampus after either 4-h propofol anesthesia alone or 2-h propofol anesthesia during a laparotomy surgery. This inhibition of autophagy was accompanied by profound α-synuclein oligomer aggregation and neurotransmitter imbalances in the hippocampus, along with hippocampus-dependent cognitive deficits. These events were not observed 18 weeks after propofol exposure with or without surgical stress. The pharmacological induction of autophagy using rapamycin markedly suppressed α-synuclein oligomerization, restored neurotransmitter equilibrium, and improved cognitive behavior after prolonged anesthesia or anesthesia combined with surgery. Thus, both prolonged propofol anesthesia alone and propofol anesthesia during surgery impaired autophagy, which may have induced abnormal hippocampal α-synuclein aggregation and neurobehavioral deficits in aged rats. These findings suggest that the activation of autophagy and the clearance of pathological α-synuclein oligomers may be novel strategies to ameliorate the common occurrence of postoperative cognitive dysfunction.

Topics: alpha-Synuclein; Anesthesia; Animals; Autophagy; Cognition Disorders; Disease Models, Animal; Hippocampus; Male; Neurons; Postoperative Complications; Rats; Surgical Procedures, Operative

Parkinson's disease (PD) is a common neurodegenerative disorder which is mostly sporadic but familial-linked PD (FPD) cases have also been found. The first reported gene mutation that linked to PD is α-synuclein (α-syn). Studies have shown that mutations, increased expression or abnormal processing of α-syn can contribute to PD, but it is believed that multiple mechanisms are involved. One of the contributing factors is post-translational modification (PTM), such as phosphorylation of α-syn at serine 129 by G-protein-coupled receptor kinases (GRKs) and casein kinase 2α (CK2α). Another known important contributing factor to PD pathogenesis is oxidative and nitrosative stress. In this study, we found that GRK6 and CK2α can be S-nitrosylated by nitric oxide (NO) both in vitro and in vivo. S-nitrosylation of GRK6 and CK2α enhanced their kinase activity towards the phosphorylation of α-syn at S129. In an A53T α-syn transgenic mouse model of PD, we found that increased GRK6 and CK2α S-nitrosylation were observed in an age dependent manner and it was associated with an increased level of pSer129 α-syn. Treatment of A53T α-syn transgenic mice with Nω-Nitro-L-arginine (L-NNA) significantly reduced the S-nitrosylation of GRK6 and CK2α in the brain. Finally, deletion of neuronal nitric oxide synthase (nNOS) in A53T α-syn transgenic mice reduced the levels of pSer129 α-syn and α-syn in an age dependent manner. Our results provide a novel mechanism of how NO through S-nitrosylation of GRK6 and CK2α can enhance the phosphorylation of pSer129 α-syn in an animal model of PD.

Topics: Age Factors; alpha-Synuclein; Animals; Casein Kinase II; Disease Models, Animal; G-Protein-Coupled Receptor Kinases; Gene Deletion; HEK293 Cells; Humans; Mice; Mice, Transgenic; Mutation; Nitric Oxide; Nitric Oxide Synthase Type I; Nitroarginine; Nitrosative Stress; Parkinson Disease; Phosphorylation; Serine

Synaptojanin1 (synj1) is a phosphoinositide phosphatase with dual SAC1 and 5'-phosphatase enzymatic activities in regulating phospholipid signaling. The brain-enriched isoform has been shown to participate in synaptic vesicle (SV) recycling. More recently, recessive human mutations were identified in the two phosphatase domains of SYNJ1, including R258Q, R459P and R839C, which are linked to rare forms of early-onset Parkinsonism. We now demonstrate that Synj1 heterozygous deletion (Synj1+/-), which is associated with an impaired 5'-phosphatase activity, also leads to Parkinson's disease (PD)-like pathologies in mice. We report that male Synj1+/- mice display age-dependent motor function abnormalities as well as alpha-synuclein accumulation, impaired autophagy and dopaminergic terminal degeneration. Synj1+/- mice contain elevated 5'-phosphatase substrate, PI(4,5)P2, particularly in the midbrain neurons. Moreover, pharmacological elevation of membrane PI(4,5)P2 in cultured neurons impairs SV endocytosis, specifically in midbrain neurons, and further exacerbates SV trafficking defects in Synj1+/- midbrain neurons. We demonstrate down-regulation of SYNJ1 transcript in a subset of sporadic PD brains, implicating a potential role of Synj1 deficiency in the decline of dopaminergic function during aging.

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Endocytosis; Haploinsufficiency; Humans; Mesencephalon; Mice; Nerve Tissue Proteins; Parkinson Disease; Phosphoric Monoester Hydrolases; Sequence Deletion

Pathologic intracellular inclusions formed from polymers of misfolded α-synuclein (αsyn) protein define a group of neurodegenerative diseases termed synucleinopathies which includes Parkinson's disease (PD). Prion-like recruitment of endogenous cellular αsyn has been demonstrated to occur in animal models of synucleinopathy, whereby misfolded αsyn can induce further pathologic αsyn inclusions to form through a prion-like mechanism. It has been suggested that misfolded αsyn may assume differing conformations which lead to varied clinical and pathological manifestations of disease; this phenomenon bears similarities to that of prion strains whereby the same misfolded protein can produce unique diseases. It is unclear what factors influence the development of unique αsyn strains, however post-translational modifications (PTMs) such as phosphorylation and truncation that are present in misfolded αsyn in disease may play a role due to their modulation of biochemical and structural αsyn properties. Herein, we investigate the prion-like properties of misfolded αsyn polymers containing either phosphomimetic (S129E) αsyn, 5 different major carboxy (C)-truncated forms of αsyn (1-115, 1-119, 1-122, 1-125, and 1-129 αsyn), or a mixture of these PTM containing αsyn forms compared to full-length (FL) αsyn in HEK293T cells and M83 transgenic mice overexpressing A53T αsyn. It is demonstrated that upon peripheral intramuscular injection of these C-truncated or S129E αsyn polymers into M83 mice, prion-like progression and time to disease onset in this mouse model is elongated when any of these PTMs are present, demonstrating that common modifications to the C-terminus of αsyn present in disease modulates the prion-like seeding properties of αsyn.

Topics: alpha-Synuclein; Animals; Central Nervous System; Disease Models, Animal; HEK293 Cells; Humans; Mice; Mice, Transgenic; Neurons; Parkinson Disease; Phosphorylation; Prions; Protein Processing, Post-Translational; Survival Analysis; Synucleinopathies

Epidemiological studies demonstrated that pesticide exposure, such as rotenone and paraquat, increases the risk of Parkinson's disease (PD). Chronic systemic exposure to rotenone, a mitochondrial complex I inhibitor, could reproduce many features of PD. However, the adoption of the models is limiting because of variability in animal sensitivity and the inability of other investigators to consistently reproduce the PD neuropathology. In addition, most of rotenone models were produced in rats. Here, we tried to establish a high-reproducible rotenone model using C57BL/6J mice. The rotenone mouse model was produced by chronic systemic exposure to a low dose of rotenone (2.5 mg/kg/day) for 4 weeks by subcutaneous implantation of rotenone-filled osmotic mini pump. The rotenone-treated mice exhibited motor deficits assessed by open field, rotarod and cylinder test and gastrointestinal dysfunction. Rotenone treatment decreased the number of dopaminergic neuronal cells in the substantia nigra pars compacta (SNpc) and lesioned nerve terminal in the striatum. In addition, we observed significant reduction of cholinergic neurons in the dorsal motor nucleus of the vagus (DMV) and the intestinal myenteric plexus. Moreover, α-synuclein was accumulated in neuronal soma in the SNpc, DMV and intestinal myenteric plexus in rotenone-treated mice. These data suggest that the low-dose rotenone mouse model could reproduce behavioral and central and peripheral neurodegenerative features of PD and be a useful model for investigation of PD pathogenesis.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Biomarkers; Cholinergic Neurons; Disease Models, Animal; Dopaminergic Neurons; Electron Transport Complex I; Environmental Exposure; Fluorescent Antibody Technique; Insecticides; Male; Mice; Mitochondria; Motor Disorders; Myenteric Plexus; Nervous System Diseases; Parkinson Disease; Rotenone; Substantia Nigra

Mutations in the GBA gene, which encodes the lysosomal enzyme glucocerebrosidase (GCase), are the most important genetic risk factor for Parkinson disease (PD). GCase activity is also decreased in sporadic PD brains and with normal ageing. Loss of GCase activity impairs the autophagy lysosomal pathway resulting in increased α-synuclein (α-syn) levels. Furthermore, elevated α-syn results in decreased GCase activity. Although the role of α-syn in PD remains unclear, evidence indicates that aggregated α-syn fibrils are a pathogenic species in PD, passing between neurons and inducing endogenous native α-syn to aggregate; spreading pathology through the brain. We have investigated if preformed α-syn fibrils (PFFs) impair GCase activity in mouse cortical neurons and differentiated dopaminergic cells, and whether GCase deficiency in these models increased the transfer of α-syn pathology to naïve cells. Neurons treated with PFFs induced endogenous α-syn to become insoluble and phosphorylated at Ser129 to a greater extent than monomeric α-syn-treatment. PFFs, but not monomeric α-syn, inhibited lysosomal GCase activity in these cells and induced the unfolded protein response. Neurons in which GCase was inhibited by conduritol β-epoxide did not increase the amount of insoluble monomeric α-syn or its phosphorylation status. Instead the release of α-syn fibrils from GCase deficient cells was significantly increased. Co-culture studies showed that the transfer of α-syn pathology to naïve cells was greater from GCase deficient cells. This study suggests that GCase deficiency increases the spread of α-syn pathology and likely contributes to the earlier age of onset and increased cognitive decline associated with GBA-PD.

Topics: Aging; alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Gaucher Disease; Glucosylceramidase; Humans; Lysosomes; Mice; Mutation; Neurons; Parkinson Disease; Phosphorylation; Synucleinopathies

Transportation of key proteins via extracellular vesicles has been recently implicated in various neurodegenerative disorders, including Parkinson's disease, as a new mechanism of disease spreading and a new source of biomarkers. Extracellular vesicles likely to be derived from the brain can be isolated from peripheral blood and have been reported to contain higher levels of α-synuclein (α-syn) in Parkinson's disease patients. However, very little is known about extracellular vesicles in multiple system atrophy, a disease that, like Parkinson's disease, involves pathological α-syn aggregation, though the process is centred around oligodendrocytes in multiple system atrophy. In this study, a novel immunocapture technology was developed to isolate blood CNPase-positive, oligodendrocyte-derived enriched microvesicles (OEMVs), followed by fluorescent nanoparticle tracking analysis and assessment of α-syn levels contained within the OEMVs. The results demonstrated that the concentrations of OEMVs were significantly lower in multiple system atrophy patients, compared to Parkinson's disease patients and healthy control subjects. It is also noted that the population of OEMVs involved was mainly in the size range closer to that of exosomes, and that the average α-syn concentrations (per vesicle) contained in these OEMVs were not significantly different among the three groups. The phenomenon of reduced OEMVs was again observed in a transgenic mouse model of multiple system atrophy and in primary oligodendrocyte cultures, and the mechanism involved was likely related, at least in part, to an α-syn-mediated interference in the interaction between syntaxin 4 and VAMP2, leading to the dysfunction of the SNARE complex. These results suggest that reduced OEMVs could be an important mechanism related to pathological α-syn aggregation in oligodendrocytes, and the OEMVs found in peripheral blood could be further explored for their potential as multiple system atrophy biomarkers.

Topics: Aged; alpha-Synuclein; Animals; Bodily Secretions; Brain; Cell-Derived Microparticles; Disease Models, Animal; Exosomes; Female; Humans; Male; Mice; Mice, Transgenic; Middle Aged; Multiple System Atrophy; Neurons; Oligodendroglia; Parkinson Disease; SNARE Proteins

Cognitive dysfunction is one of the most disabling non-motor symptoms of Parkinson's disease (PD), though its pathological correlates still remain elusive. Hippocampal Lewy pathology has recently been correlated by compelling evidence from post-mortem and imaging studies. Animal models recapitulating cognitive impairment in PD are essential to better understand the underlying pathophysiology. To investigate the hippocampal involvement in cognitive dysfunction of PD, we generated an experimental model by inducing midbrain and hippocampal α-synuclein pathology simultaneously.. Rats were injected either with human α-synuclein or green fluorescent protein (GFP) expressing adeno-associated viral vectors (AAV), or saline bilaterally into substantia nigra (SN) and dentate gyrus (DG). A group of untreated animals were used as naïve controls. Cognitive and behavioral changes were evaluated with tests probing for spatial learning, short-term memory, anxiety and hedonistic behavior. Immunohistochemical staining, immunoblotting and stereological analysis were performed for pathological characterization.. Bilateral α-synuclein overexpression in SN and DG led to mild but significant motor impairment as well as dysfunctions in short-term memory and spatial learning. There was no hedonistic deficit, whereas a hypo-anxious state was induced. While stereological analysis revealed no significant neuronal loss in any sectors of cornu ammonis, there was considerable decrease (43%) in TH. Bilateral α-synuclein overexpression in DG and SN reproduced partial motor and hippocampus related cognitive deficits. Using this model, we showed a predisposition of CA2 for pathological α-synuclein accumulation, which may provide further insights for future experimental and clinical studies.

Topics: alpha-Synuclein; Animals; CA2 Region, Hippocampal; Cognitive Dysfunction; Dentate Gyrus; Disease Models, Animal; Female; Humans; Parkinson Disease; Rats; Rats, Sprague-Dawley; Substantia Nigra

α-Synuclein protein (α-syn) is a central player in Parkinson's disease (PD) and in a spectrum of neurodegenerative diseases collectively known as synucleinopathies. These diseases are characterized by abnormal motor symptoms, such as tremor at rest, slowness of movement, rigidity of posture, and bradykinesia. Histopathological features of PD include preferential loss of dopaminergic neurons in the substantia nigra and formation of fibrillar intraneuronal inclusions called Lewy bodies and Lewy neurites, which are composed primarily of the α-syn protein. Currently, it is well accepted that α-syn oligomers (αSO) are the main toxic agent responsible for the etiology of PD. Glutamatergic excitotoxicity is associated with several neurological disorders, including PD. Excess glutamate in the synaptic cleft can be taken up by the astrocytic glutamate transporters GLAST and GLT-1. Although this event is the main defense against glutamatergic excitotoxicity, the molecular mechanisms that regulate this process have not yet been investigated in an early sporadic model of synucleinopathy. Here, using an early sporadic model of synucleinopathy, we demonstrated that the treatment of astrocytes with αSO increased glutamate uptake. This was associated with higher levels of GLAST and GLT-1 in astrocyte cultures and in a mouse model of synucleinopathy 24 h and 45 days after inoculation with αSO, respectively. Pharmacological inhibition of the TGF-β1 (transforming growth factor beta 1) pathway in vivo reverted GLAST/GLT-1 enhancement induced by αSO injection. Therefore, our study describes a new neuroprotective role of astrocytes in an early sporadic model of synucleinopathy and sheds light on the mechanisms of glutamate transporter regulation for neuroprotection against glutamatergic excitotoxicity in synucleinopathy.

Topics: alpha-Synuclein; Amino Acid Transport System X-AG; Animals; Animals, Newborn; Astrocytes; Cells, Cultured; Disease Models, Animal; Female; Mice; Pregnancy; Synucleinopathies

Parkinson's disease (PD) is the second most prevalent late-age onset neurodegenerative disorder, affecting 1% of the population after the age of about 60 years old and 4% of those over 80 years old, causing motor impairments and cognitive dysfunction. Increasing evidence indicates that Mediterranean diet (MD) exerts beneficial effects in maintaining health, especially during ageing and by the prevention of neurodegenerative disorders. In this regard, olive oil and its biophenolic constituents like hydroxytyrosol (HT) have received growing attention in the past years. Thus, in the current study we test the health-promoting effects of two hydroxytyrosol preparations, pure HT and Hidrox

Topics: Aging; alpha-Synuclein; Animals; Animals, Genetically Modified; Biomarkers; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Diet, Mediterranean; Disease Models, Animal; Dopaminergic Neurons; Humans; Longevity; Microscopy, Fluorescence; Olea; Olive Oil; Parkinson Disease; Polyphenols; Rotenone

Neurodegenerative disorders, including Alzheimer's (AD) and Parkinson's diseases (PD), are characterised by the formation of aberrant assemblies of misfolded proteins. The discovery of disease-modifying drugs for these disorders is challenging, in part because we still have a limited understanding of their molecular origins. In this review, we discuss how biophysical approaches can help explain the formation of the aberrant conformational states of proteins whose neurotoxic effects underlie these diseases. We discuss in particular models based on the transgenic expression of amyloid-β (Aβ) and tau in AD, and α-synuclein in PD. Because biophysical methods have enabled an accurate quantification and a detailed understanding of the molecular mechanisms underlying protein misfolding and aggregation in vitro, we expect that the further development of these methods to probe directly the corresponding mechanisms in vivo will open effective routes for diagnostic and therapeutic interventions.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Disease Models, Animal; Gene Expression; Parkinson Disease; Protein Aggregates; Protein Folding; tau Proteins

Synucleinopathies such as multiple system atrophy (MSA) and Parkinson's disease are associated with a variety of visual symptoms. Functional and morphological retinal aberrations are therefore supposed to be valuable biomarkers for these neurodegenerative diseases. This study examined the retinal morphology and functionality resulting from human α-synuclein (α-Syn) overexpression in the transgenic Plp-α-Syn mouse model.. Immunohistochemistry on retinal sections and whole-mounts was performed on 8- to 11-week-old and 12-month-old Plp-α-Syn mice and C57BL/6N controls. Quantitative RT-PCR experiments were performed to study the expression of endogenous and human α-Syn and tyrosine hydroxylase (TH). We confirmed the presence of human α-Syn in the retina in western blot analyses. Multi-electrode array (MEA) analyses from light-stimulated whole-mounted retinas were used to investigate their functionality.. Biochemical and immunohistochemical analyses showed human α-Syn in the retina of Plp-α-Syn mice. We found distinct staining in different retinal cell layers, most abundantly in rod bipolar cells of the peripheral retina. In the periphery, we also observed a trend toward a decline in the number of retinal ganglion cells. The number of TH+ neurons was unaffected in this human α-Syn overexpression model. MEA recordings showed that Plp-α-Syn retinas were functional but exhibited mild alterations in dim light conditions.. Together, these findings implicate an impairment of retinal neurons in the Plp-α-Syn mouse. The phenotype partly relates to retinal deficits reported in MSA patients. We further propose the suitability of the Plp-α-Syn retina as a biological model to study synuclein-mediated mechanisms.

Topics: alpha-Synuclein; Animals; Blotting, Western; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Electroretinography; Female; Glial Fibrillary Acidic Protein; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Microscopy, Confocal; Myelin Proteolipid Protein; Optic Nerve; Photic Stimulation; Real-Time Polymerase Chain Reaction; Retina; Retinal Diseases; Retinal Neurons; Synucleinopathies

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; DNA-Binding Proteins; Dopaminergic Neurons; Gene Knockout Techniques; Humans; Lewy Body Disease; Locomotion; Longevity; Protein Aggregation, Pathological; RNA-Binding Proteins

Neurodegenerative diseases are characterized by the accumulation of specific phosphorylated protein aggregates in the brain, such as hyperphosphorylated tau (hp-tau) in tauopathies and phosphorylated α-synuclein (p-αSyn) in α-synucleinopathies. The simultaneous accumulation of different proteins is a common event in many neurodegenerative diseases. We herein describe the detection of the phosphorylation and dimerization of αSyn and activation of GSK-3β, a major kinase known to phosphorylate tau and αSyn, in the brains of rTg4510 mice that overexpress human P301L mutant tau. Immunohistochemistry showed p-αSyn aggregates in rTg4510 mice, which were suppressed by doxycycline-mediated decreases in mutant tau expression levels. A semi-quantitative analysis revealed a regional correlation between hp-tau and p-αSyn accumulation in rTg4510 mice. Furthermore, proteinase K-resistant αSyn aggregates were found in the region with excessive hp-tau accumulation in rTg4510 mice, and these aggregates were morphologically different from proteinase K-susceptible p-αSyn aggregates. Western blotting revealed decreases in p-αSyn monomers in TBS- and sarkosyl-soluble fractions and increases in ubiquitinated p-αSyn dimers in sarkosyl-soluble and insoluble fractions in rTg4510 mice. Furthermore, an activated form of GSK-3β was immunohistochemically detected within cells containing both hp-tau and p-αSyn aggregates. A semi-quantitative analysis revealed that increased GSK-3β activity strongly correlated with hp-tau and p-αSyn accumulation in rTg4510 mice. Collectively, the present results suggest that the overexpression of human P301L mutant tau promoted the phosphorylation and dimerization of endogenous αSyn by activating GSK-3β in rTg4510 mice. This synergic effect between tau, αSyn, and GSK-3β may be involved in the pathophysiology of several neurodegenerative diseases that show the accumulation of both tau and αSyn.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Glycogen Synthase Kinase 3 beta; Humans; Mice, Inbred C57BL; Mice, Transgenic; Phosphorylation; Protein Aggregation, Pathological; tau Proteins; Tauopathies

Parkinson's disease (PD) is the second most common neurodegenerative disorder, but the disease-modifying therapies focusing on the core pathological changes are still unavailable. Rho-associated protein kinase (ROCK) has been suggested as a promising target for developing neuroprotective therapies in PD.. We aimed to explore the promotion of α-synuclein (α-syn) clearance in a rat model.. In a rat model induced by unilateral injection of adeno-associated virus of serotype 9 (AAV9) expressing A53T α-syn (AAV9-A53T-α-syn) into the right substantia nigra, we aimed to investigate whether Fasudil could promote α-syn clearance and thereby attenuate motor impairments and dopaminergic deficits.. In our study, treatment with Fasudil (5 mg/kg rat weight/day) for 8 weeks significantly improved the motor deficits in the Cylinder and Rotarod tests. In the in vivo positron emission tomography imaging with the ligand 18F-dihydrotetrabenazine, Fasudil significantly enhanced the dopaminergic imaging in the injected striatum of the rat model (p < 0.05 vs. vehicle group, p < 0.01 vs. left striatum in Fasudil group). The following mechanistic study confirmed that Fasudil could promote the autophagic clearance of α-syn by Becline 1 and Akt/mTOR pathways.. Our study suggested that Fasudil, the ROCK2 inhibitor, could attenuate the anatomical and behavioral lesions in the Parkinsonian rat model by autophagy activation. Our results identify Fasudil as a drug with high translational potential as disease-modifying treatment for PD and other synucleinopathies.

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Neurodegenerative Diseases; Parkinson Disease; Rats, Sprague-Dawley; Substantia Nigra

Parkinson's disease has become one of the most common neurodegenerative diseases. Pathological changes typically manifest following dopaminergic neuron loss in the substantia nigra and abnormal alpha-synuclein (α-syn) aggregation in the neurons. α-Syn is the major component of Lewy bodies. However, research pertaining to the spread of abnormal α-syn aggregations, which results in specific damage to the brain structure and function, is lacking. In the present study, full-length human α-syn fibrils were injected into the medial forebrain bundle of rats, with an experimental endpoint of 6 months. Histological analysis was conducted to observe the pathological progress of abnormal endogenous α-syn aggregation and nerve fiber quality. Changes in gray and white matter integrity were quantitatively analyzed using voxel-based morphometry (VBM). Behavioral changes were observed over the 6-month period. Histological analysis showed reduced dopamine transporter levels in the striatum of the experimental rats; widespread abnormal endogenous α-syn accumulation; and damaged, sparse, and disordered nerve fibers in the experimental group. VBM showed that at 6 months after surgery, bilateral anterior limbic, bilateral inferior limbic, right hippocampal, and right cortical volumes had reduced, whereas thalamic volume had increased in the experimental group compared with that in the control group. Damage to the limbic and thalamic fiber structure may occur in the earlier stages of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Male; Medial Forebrain Bundle; Parkinson Disease; Phosphorylation; Protein Aggregation, Pathological; Rats, Sprague-Dawley; Serine

Different genetic backgrounds can modify the effect of mutated genes. Human α-synuclein (

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Bacterial Proteins; Body Size; Caenorhabditis elegans; Disease Models, Animal; Gene Expression Regulation; Genetic Variation; Genome; Humans; Luminescent Proteins; Lysosomes; Multifactorial Inheritance; Parkinson Disease; Transcription, Genetic

Neurodegenerative disorders (ND) like Alzheimer's (AD), Parkinson's (PD), Huntington's or Prion diseases share similar pathological features. They are all age dependent and are often associated with disruptions in analogous metabolic processes such as protein aggregation and oxidative stress, both of which involve metal ions like copper, manganese and iron. Bush and Tanzi proposed 2008 in the 'metal hypothesis of Alzheimer's disease' that a breakdown in metal homeostasis is the main cause of NDs, and drugs restoring metal homeostasis are promising novel therapeutic strategies. We report here that metallothionein (MT), an endogenous metal detoxifying protein, is increased in young amyloid ß (Aß) expressing Caenorhabditis elegans, whereas it is not in wild type strains. Further MT induction collapsed in 8 days old transgenic worms, indicating the age dependency of disease outbreak, and sharing intriguing parallels to diminished MT levels in human brains of AD. A medium throughput screening assay method was established to search for compounds increasing the MT level. Compounds known to induce MT release like progesterone, ZnSO

Topics: Aging; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Benzothiazoles; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Clioquinol; Disease Models, Animal; Emodin; Gene Knockdown Techniques; Homeostasis; Metallothionein; Metals; Neuroprotective Agents; Parkinson Disease; Quercetin; Signal Transduction

Olfactory dysfunction is one of the early symptoms seen in Parkinson's disease (PD). However, the mechanisms underlying olfactory pathology that impacts PD disease progression and post-mortem appearance of alpha-Synuclein (α-Syn) inclusions in and beyond olfactory bulb in PD remain unclear. It has been suggested that environmental toxins inhaled through the nose can induce inflammation in the olfactory bulb (OB), where Lewy body (LB) is the first to be found, and then, spread to related brain regions. We hypothesize that OB inflammation triggers local α-Syn pathology and promotes its spreading to cause PD. In this study, we evaluated this hypothesis by intranasal infusion of lipopolysaccharides (LPS) to induce OB inflammation in mice and examined cytokines expression and PD-like pathology. We found intranasal LPS-induced microglia activation, inflammatory cytokine expression and α-Syn overexpression and aggregation in the OB via interleukin-1β (IL-1β)/IL-1 receptor type I (IL-1R1) dependent signaling. In addition, an aberrant form of α-Syn, the phosphorylated serine 129 α-Syn (pS129 α-Syn), was found in the OB, substantia nigra (SN) and striatum 6 weeks after the LPS treatment. Moreover, 6 weeks after the LPS treatment, mice showed reduced SN tyrosine hydroxylase, decreased striatal dopaminergic metabolites and PD-like behaviors. These changes were blunted in IL-1R1 deficient mice. Further studies found the LPS treatment inhibited IL-1R1-dependent autophagy in the OB. These results suggest that IL-1β/IL-1R1 signaling in OB play a vital role in the induction and propagation of aberrant α-Syn, which may ultimately trigger PD pathology.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Female; Interleukin-1beta; Lipopolysaccharides; Male; Mice; Mice, Knockout; Motor Activity; Olfactory Bulb; Receptors, Interleukin-1; Signal Transduction; Smell; Substantia Nigra

Biomarkers suitable for early diagnosis and monitoring disease progression are the cornerstone of developing disease-modifying treatments for neurodegenerative diseases such as Parkinson's disease (PD). Besides motor complications, PD is also characterized by deficits in visual processing. Here, we investigate how virally-mediated overexpression of α-synuclein in the substantia nigra pars compacta impacts visual processing in a well-established rodent model of PD. After a unilateral injection of vector, human α-synuclein was detected in the striatum and superior colliculus (SC). In parallel, there was a significant delay in the latency of the transient VEPs from the affected side of the SC in late stages of the disease. Inhibition of leucine-rich repeat kinase using PFE360 failed to rescue the VEP delay and instead increased the latency of the VEP waveform. A support vector machine classifier accurately classified rats according to their `disease state' using frequency-domain data from steady-state visual evoked potentials (SSVEP). Overall, these findings indicate that the latency of the rodent VEP is sensitive to changes mediated by the increased expression of α-synuclein and especially when full overexpression is obtained, whereas the SSVEP facilitated detection of α-synuclein across reflects all stages of PD model progression.

Topics: alpha-Synuclein; Animals; Biomarkers; Dependovirus; Disease Models, Animal; Electrophysiological Phenomena; Evoked Potentials, Visual; Female; Gene Expression; Genetic Vectors; Humans; Immunohistochemistry; Machine Learning; Mice, Transgenic; Parkinson Disease; Rats; Visual Cortex; Visual Perception

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor impairments. Most PD drugs act by improving motor impairments, whereas very few drugs that efficiently recover PD-related neuropathological features, particularly α-synuclein-related toxicity, have been developed. In this study, we found that papaverine (PAP) attenuated behavioral deficits and protected against nigrostriatal dopaminergic degeneration in the subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/P) mouse model of PD. Histological analysis of tissue dissected from mice sacrificed nearly 3 weeks after the completion of treatment revealed that PAP significantly ameliorated microglia/astrocyte activation in the striatum and substantia nigra of MPTP/P-treated mice. In addition, PAP diminished α-synuclein expression and aggregation in this model. Furthermore, PAP inhibited the phosphorylation of α-synuclein at serine 129, which may underlie the observed reduction in α-synuclein aggregation. PAP also reduced the expression of matrix metalloproteinase-3 (MMP-3), and the MMP3-positive area co-labeled with thioflavin-S. Taken together, our data suggest that PAP inhibits dopaminergic neuronal cell death and α-synuclein aggregation by suppressing neuroinflammation and MMP-3 expression in the subacute MPTP/P mouse model of PD. Accordingly, PAP may be a promising drug for the treatment of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Astrocytes; Disease Models, Animal; Dopaminergic Neurons; Male; Matrix Metalloproteinase 3; Mice, Inbred C57BL; Microglia; MPTP Poisoning; Neuroprotective Agents; Neurotoxins; Papaverine; Protein Aggregation, Pathological

Parkinson's disease (PD), a calamitous neurodegenerative disorder with no cure till date, is closely allied with the misfolding and aggregation of α-Synuclein (α -Syn). Inhibition of α-Syn aggregation is one of the optimistic approaches for the treatment for PD. Here, we carried out hypothesis-driven studies towards synthesising a series of pyrazolo-pyridine carboxylate containing compounds (7a-7m) targeted at reducing deleterious α-Syn aggregation. The target compounds were synthesized through multi-step organic synthesis reactions. From docking studies, compounds 7b, 7g and 7i displayed better interaction with the key residues of α-Syn with values: -6.8, -8.9 and -7.2 Kcal/mol, respectively. In vivo transgenic C. elegans model of Synucleinopathy was used to evaluate the ability of the designed and synthesized compounds to inhibit α-Syn aggregation. These lead compounds 7b, 7g and 7i displayed 1.7, 2.4 and 1.5-fold inhibition of α-Syn with respect to the control. Further, the strategy of employing pyrazolo-pyridine-based compounds worked with success and these scaffolds could be further modified and validated for betterment of endpoints associated with PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Binding Sites; Caenorhabditis elegans; Disease Models, Animal; Drug Design; Ligands; Molecular Docking Simulation; Optical Imaging; Protein Aggregates; Pyrazoles; Pyridines; Synucleinopathies

The role of Discoidin Domain Receptors (DDRs) is poorly understood in neurodegeneration. DDRs are upregulated in Alzheimer's and Parkinson's disease (PD), and DDRs knockdown reduces neurotoxic protein levels. Here we show that potent and preferential DDR1 inhibitors reduce neurotoxic protein levels in vitro and in vivo. Partial or complete deletion or inhibition of DDR1 in a mouse model challenged with α-synuclein increases autophagy and reduces inflammation and neurotoxic proteins. Significant changes of cerebrospinal fluid microRNAs that control inflammation, neuronal injury, autophagy and vesicular transport genes are observed in PD with and without dementia and Lewy body dementia, but these changes are attenuated or reversed after treatment with the DDR1 inhibitor, nilotinib. Collectively, these data demonstrate that DDR1 regulates autophagy and reduces neurotoxic proteins and inflammation and is a therapeutic target in neurodegeneration.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Discoidin Domain Receptor 1; Disease Models, Animal; Humans; Inflammation; Lewy Body Disease; Mice; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; Pyrimidines

Parkinson's Disease (PD) is characterized by both motor and non-motor symptoms. The presynaptic neuronal protein, α-Synuclein, plays a pivotal role in PD pathogenesis and is associated with both genetic and sporadic origin of the disease. Ursolic Acid (UA) is a well-known bioactive compound found in various medicinal plants, widely studied for its anti-inflammatory and antioxidant activities.. In this research article, the neuroprotective potential of UA has been further explored in the Rotenone-induced mouse model of PD.. To investigate our hypothesis, we have divided mice into 4 different groups, control, drug only control, Rotenone-intoxicated group, and Rotenone-intoxicated mice treated with UA. After the completion of dosing, behavioral parameters were estimated. Then mice from each group were sacrificed and the brains were isolated. Further, the biochemical tests were assayed to check the balance between the oxidative stress and endogenous anti-oxidants; and TH (Tyrosine Hydroxylase), α-Synuclein, Akt (Serine-threonine protein kinase), ERK (Extracellular signal-regulated kinase) and inflammatory parameters like Nuclear Factor-κB (NF-κB) and Tumor Necrosis Factor- α (TNF-α) were assessed using Immunohistochemistry (IHC). Western blotting was also done to check the expressions of TH and α-Synuclein. Moreover, the expression levels of PD related genes like α-Synuclein, β-Synuclein, Interleukin-1β (IL-1β), and Interleukin-10 (IL-10) were assessed by using Real-time PCR.. The results obtained in our study suggested that UA significantly reduced the overexpression of α-Synuclein and regulated the phosphorylation of survival-related kinases (Akt and ERK) apart from alleviating the behavioral abnormalities and protecting the dopaminergic neurons from oxidative stress and neuroinflammation.. Thus, our study shows the neuroprotective potential of UA, which can further be explored for possible clinical intervention.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Antioxidants; Brain; Disease Models, Animal; Dopaminergic Neurons; Male; Mice; Neuroprotection; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Rotenone; Triterpenes; Ursolic Acid

Alpha-synucleinopathies are a group of progressive neurodegenerative disorders, characterized by intracellular deposits of aggregated α-synuclein (αS). The clinical heterogeneity of these diseases is thought to be attributed to conformers (or strains) of αS but the contribution of inclusions in various cell types is unclear. The aim of the present work was to study αS conformers among different transgenic (TG) mouse models of α-synucleinopathies. To this end, four different TG mouse models were studied (Prnp-h[A53T]αS; Thy1-h[A53T]αS; Thy1-h[A30P]αS; Thy1-mαS) that overexpress human or murine αS and differed in their age-of-symptom onset and subsequent disease progression. Postmortem analysis of end-stage brains revealed robust neuronal αS pathology as evidenced by accumulation of αS serine 129 (p-αS) phosphorylation in the brainstem of all four TG mouse lines. Overall appearance of the pathology was similar and only modest differences were observed among additionally affected brain regions. To study αS conformers in these mice, we used pentameric formyl thiophene acetic acid (pFTAA), a fluorescent dye with amyloid conformation-dependent spectral properties. Unexpectedly, besides the neuronal αS pathology, we also found abundant pFTAA-positive inclusions in microglia of all four TG mouse lines. These microglial inclusions were also positive for Thioflavin S and showed immunoreactivity with antibodies recognizing the N-terminus of αS, but were largely p-αS-negative. In all four lines, spectral pFTAA analysis revealed conformational differences between microglia and neuronal inclusions but not among the different mouse models. Concomitant with neuronal lesions, microglial inclusions were already present at presymptomatic stages and could also be induced by seeded αS aggregation. Although nature and significance of microglial inclusions for human α-synucleinopathies remain to be clarified, the previously overlooked abundance of microglial inclusions in TG mouse models of α-synucleinopathy bears importance for mechanistic and preclinical-translational studies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Inclusion Bodies; Mice; Mice, Transgenic; Microglia; Neurons; Protein Aggregation, Pathological; Protein Conformation; Synucleinopathies

The present study was aimed to study the effect of kaempferol, on the transgenic Drosophila model of Parkinson's disease. Kaempferol was added in the diet at final concentration of 10, 20, 30 and 40 µM and the effect was studied on various cognitive and oxidative stress markers. The results of the study showed that kaempferol, delayed the loss of climbing ability as well as the activity of PD flies in a dose dependent manner compared to unexposed PD flies. A dose-dependent reduction in oxidative stress markers was also observed. Histopathological examination of fly brains using anti-tyrosine hydroxylase immunostaining has revealed a significant dose-dependent increase in the expression of tyrosine hydroxylase in PD flies exposed to kaempferol. Molecular docking results revealed that kaempferol binds to human alpha synuclein at specific sites that might results in the inhibition of alpha synuclein aggregation and prevents the formation of Lewy bodies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila; Humans; Kaempferols; Lewy Bodies; Motor Activity; Parkinson Disease; Protein Aggregation, Pathological; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is the second most prevalent movement disorder characterized by up to 80% loss of dopamine (DA) neurons and accumulation of Lewy body deposits composed of α-synuclein (α-syn). Accumulation of α-syn is associated with microglial activation, leading to a pro-inflammatory environment linked with the pathogenesis of PD. Along with microglia, CD4 and CD8 T cells are observed in SNpc. The contribution of T-cells to PD development remains unclear with studies demonstrating that they may mediate neurodegeneration or act in a neuroprotective manner.. Here, we assessed the contribution of T cells to PD neurodegeneration using an adeno-associated virus (AAV) coding human wild-type α-syn or GFP injected into the substantia nigra pars compacta (SNpc) in T cell deficient (athymic nude) and T cell competent (heterozygous) rats. The rats were behaviorally assessed with cylinder test to test paw bias. Following behavior testing, brains were collected and analyzed for markers of dopamine neuron, microglial activation, T cells, and α-syn expression.. Injection of AAV9-α-syn unilaterally into the SN of T cell competent rats resulted in a significant paw bias in comparison to the controls at 60 days post-injection. Conversely, T cell-deficient rats injected with AAV9-α-syn showed no deficit in paw bias. As expected, injected T cell competent rats demonstrated a significant increase in microglial activation (MHCII staining) as well as significant dopaminergic neuron loss. In contrast, the T cell-deficient counterparts did not show a significant increase in microglial activation or significant neuron loss compared to the control animals. We also observed CD4 and CD8 T cells in SNpc following microglial MHCII expression and dopaminergic neuron loss. The time course of T cell entry correlates with upregulation of MHCII and the peak loss of TH+ cells in the SNpc.. These data demonstrate that T cell infiltration and microglial upregulation of MHCII are involved in α-synuclein-mediated DA neuron loss in this rat model of PD.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Male; Microglia; Neurons; Parkinson Disease; Rats; Rats, Nude; Substantia Nigra; T-Lymphocytes; Up-Regulation

Progressive neuronal death in monoaminergic nuclei and widespread accumulation of α-synuclein are neuropathological hallmarks of Parkinson's disease (PD). Given that α-synuclein may be an early mediator of the pathological cascade that ultimately leads to neurodegeneration, decreased α-synuclein synthesis will abate neurotoxicity if delivered to the key affected neurons.. We used a non-viral gene therapy based on a new indatraline-conjugated antisense oligonucleotide (IND-ASO) to disrupt the α-synuclein mRNA transcription selectively in monoamine neurons of a PD-like mouse model and elderly nonhuman primates. Molecular, cell biology, histological, neurochemical and behavioral assays were performed.. Intracerebroventricular and intranasal IND-ASO administration for four weeks in a mouse model with AAV-mediated wild-type human α-synuclein overexpression in dopamine neurons prevented the synthesis and accumulation of α-synuclein in the connected brain regions, improving dopamine neurotransmission. Likewise, the four-week IND-ASO treatment led to decreased levels of endogenous α-synuclein protein in the midbrain monoamine nuclei of nonhuman primates, which are affected early in PD.. The inhibition of α-synuclein production in dopamine neurons and its accumulation in cortical/striatal projection areas may alleviate the early deficits of dopamine function, showing the high translational value of antisense oligonucleotides as a disease modifying therapy for PD and related synucleinopathies.. Grants SAF2016-75797-R, RTC-2014-2812-1 and RTC-2015-3309-1, Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (ERDF), UE; Grant ID 9238, Michael J. Fox Foundation; and Centres for Networked Biomedical Research on Mental Health (CIBERSAM), and on Neurodegenerative Diseases (CIBERNED).

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Female; Gene Expression; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Haplorhini; Humans; Immunohistochemistry; Male; Mice; Morris Water Maze Test; Neurons; Oligonucleotides, Antisense; Parkinson Disease; Synaptic Transmission; Treatment Outcome

Increased expression of α-Syn (α-Synuclein) is known to mediate secondary brain damage after stroke. We presently studied if α-Syn knockdown can protect ischemic brain irrespective of sex and age.. Adult and aged male and female mice were subjected to transient middle cerebral artery occlusion. α-Syn small interfering RNA (siRNA) was administered intravenous at 30 minutes or 3 hour reperfusion. Poststroke motor deficits were evaluated between day 1 and 7 and infarct volume was measured at day 7 of reperfusion.. α-Syn knockdown significantly decreased poststroke brain damage and improved poststroke motor function recovery in adult and aged mice of both sexes. However, the window of therapeutic opportunity for α-Syn siRNA is very limited.. α-Syn plays a critical role in ischemic brain damage and preventing α-Syn protein expression early after stroke minimizes poststroke brain damage leading to better functional outcomes irrespective of age and sex.

Topics: Age Factors; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Female; Gene Knockdown Techniques; Infarction, Middle Cerebral Artery; Male; Mice; Recovery of Function; RNA, Small Interfering; Sex Factors; Stroke

It is necessary to develop an understanding of the specific mechanisms involved in alpha-synuclein aggregation and propagation to develop disease modifying therapies for age-related synucleinopathies, including Parkinson's disease and Dementia with Lewy Bodies. To adequately address this question, we developed a new transgenic mouse model of synucleinopathy that expresses human A53T SynGFP under control of the mouse prion protein promoter. Our characterization of this mouse line demonstrates that it exhibits several distinct advantages over other, currently available, mouse models. This new model allows rigorous study of the initial location of Lewy pathology formation and propagation in the living brain, and strongly suggests that aggregation begins in axonal structures with retrograde propagation to the cell body. This model also shows expeditious development of alpha-synuclein pathology following induction with small, in vitro-generated alpha-synuclein pre-formed fibrils (PFFs), as well as accelerated cell death of inclusion-bearing cells. Using this model, we found that aggregated alpha-synuclein somatic inclusions developed first in neurons, but later showed a second wave of inclusion formation in astrocytes. Interestingly, astrocytes appear to survive much longer after inclusion formation than their neuronal counterparts. This model also allowed careful study of peripheral-to-central spread of Lewy pathology after PFF injection into the hind limb musculature. Our results clearly show evidence of progressive, retrograde trans-synaptic spread of Lewy pathology through known neuroanatomically connected pathways in the motor system. As such, we have developed a promising tool to understand the biology of neurodegeneration associated with alpha-synuclein aggregation and to discover new treatments capable of altering the neurodegenerative disease course of synucleinopathies.

Topics: alpha-Synuclein; Animals; Astrocytes; Axons; Brain; Disease Models, Animal; Female; Humans; Lewy Bodies; Male; Mice; Mice, Transgenic; Neurons; Protein Transport; Synucleinopathies

The study was to investigate whether immunoproteasome (i-proteasome) and its downstream pathway are related to the pathogenesis of Parkinson's disease (PD). Rats were treated with rotenone showed significant weight loss and dyskinesia, which is consistent with the degeneration of TH-positive neurons and the activation of Iba-1-positive microglia/macrophages. Two major catalytic subunits of i-proteasome (PSMB9 and PSMB8) were seldom expressed in rat substantia nigra (SN) under normal condition, but they were significantly up-regulated with the release of TNF-α and IFN-γ after exposure to rotenone. In addition, compared with control group, the antigen presentation-related proteins antigen peptide transporter (TAP) 1, TAP2, major histocompatibility complex (MHC)-I and MHC-II levels were significantly up-regulated in rotenone group, which was in line with the accumulation of α-syn. These findings suggested that i-proteasome and antigen presentation pathways (related proteins) were upregulated by rotenone in a PD rat model.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Male; Microglia; Parkinson Disease; Proteasome Endopeptidase Complex; Rats, Wistar; Rotenone; Substantia Nigra; Up-Regulation

Parkinson's disease (PD) is a progressive neurodegenerative disorder thought to be caused by accumulation of α-synuclein (α-syn) within the brain, autonomic nerves, and the enteric nervous system (ENS). Involvement of the ENS in PD often precedes the onset of the classic motor signs of PD by many years at a time when severe constipation represents a major morbidity. Studies conducted in vitro and in vivo, have shown that squalamine, a zwitterionic amphipathic aminosterol, originally isolated from the liver of the dogfish shark, effectively displaces membrane-bound α-syn.. Here we explore the electrophysiological effect of squalamine on the gastrointestinal (GI) tract of mouse models of PD engineered to express the highly aggregating A53T human α-syn mutant.. GI motility and in vivo response to oral squalamine in PD model mice and controls were assessed using an in vitro tissue motility protocol and via fecal pellet output. Vagal afferent response to squalamine was measured using extracellular mesenteric nerve recordings from the jejunum. Whole cell patch clamp was performed to measure response to squalamine in the myenteric plexus.. Squalamine effectively restores disordered colonic motility in vivo and within minutes of local application to the bowel. We show that topical squalamine exposure to intrinsic primary afferent neurons (IPANs) of the ENS rapidly restores excitability.. These observations may help to explain how squalamine may promote gut propulsive activity through local effects on IPANs in the ENS, and further support its possible utility in the treatment of constipation in patients with PD.

Topics: alpha-Synuclein; Animals; Cholestanols; Constipation; Disease Models, Animal; Electrophysiological Phenomena; Enteric Nervous System; Gastrointestinal Motility; Jejunum; Mice; Mice, Transgenic; Mutant Proteins; Myenteric Plexus; Neurons, Afferent; Parkinson Disease; Patch-Clamp Techniques; Vagus Nerve

Parkinson's disease (PD) neuropathology is characterized by intraneuronal protein aggregates composed of misfolded α-Synuclein (α-Syn), as well as degeneration of substantia nigra dopamine neurons. Deficits in olfactory perception and aggregation of α-Syn in the olfactory bulb (OB) are observed during early stages of PD, and have been associated with the PD prodrome, before onset of the classic motor deficits. α-Syn fibrils injected into the OB of mice cause progressive propagation of α-Syn pathology throughout the olfactory system and are coupled to olfactory perceptual deficits.. We hypothesized that accumulation of pathogenic α-Syn in the OB impairs neural activity in the olfactory system.. To address this, we monitored spontaneous and odor-evoked local field potential dynamics in awake wild type mice simultaneously in the OB and piriform cortex (PCX) one, two, and three months following injection of pathogenic preformed α-Syn fibrils in the OB.. We detected α-Syn pathology in both the OB and PCX. We also observed that α-Syn fibril injections influenced odor-evoked activity in the OB. In particular, α-Syn fibril-injected mice displayed aberrantly high odor-evoked power in the beta spectral range. A similar change in activity was not detected in the PCX, despite high levels of α-Syn pathology.. Together, this work provides evidence that synucleinopathy impacts in vivo neural activity in the olfactory system at the network-level.

Topics: alpha-Synuclein; Animals; Beta Rhythm; Disease Models, Animal; Evoked Potentials; Mice; Olfactory Bulb; Olfactory Perception; Piriform Cortex; Synucleinopathies

Parkinson's disease (PD) is considered a synucleinopathy because of the intraneuronal accumulation of aggregated α-synuclein (αSyn). Recent evidence points to soluble αSyn-oligomers (αSynO) as the main cytotoxic species responsible for cell death. Given the pivotal role of αSyn in PD, αSyn-based models are crucial for the investigation of toxic mechanisms and the identification of new therapeutic targets in PD. By using a metabolomics approach, we evaluated the metabolic profile of brain and serum samples of rats infused unilaterally with preformed human αSynOs (HαSynOs), or vehicle, into the substantia nigra pars compacta (SNpc). Three months postinfusion, the striatum was dissected for striatal dopamine (DA) measurements via High Pressure Liquid Chromatography (HPLC) analysis and mesencephalon and serum samples were collected for the evaluation of metabolite content via gas chromatography mass spectrometry analysis. Multivariate, univariate and correlation statistics were applied. A 40% decrease of DA content was measured in the HαSynO-infused striatum as compared to the contralateral and the vehicle-infused striata. Decreased levels of dehydroascorbic acid, myo-inositol, and glycine, and increased levels of threonine, were found in the mesencephalon, while increased contents of fructose and mannose, and a decrease in glycine and urea, were found in the serum of HαSynO-infused rats. The significant correlation between DA and metabolite content indicated that metabolic variations reflected the nigrostriatal degeneration. Collectively, the metabolomic fingerprint of HαSynO-infused rats points to an increase of oxidative stress markers, in line with PD neuropathology, and provides hints for potential biomarkers of PD.

Topics: alpha-Synuclein; Animals; Biomarkers; Corpus Striatum; Disease Models, Animal; Dopamine; Humans; Male; Metabolome; Metabolomics; Neurons; Oxidative Stress; Parkinson Disease; Rats; Rats, Sprague-Dawley; Substantia Nigra

Pathogenic mutations in the leucine-rich repeat kinase 2 (LRRK2) gene belong to the most common genetic causes of inherited Parkinson's disease (PD) and variations in its locus increase the risk to develop sporadic PD. Extensive research efforts aimed at understanding how changes in the LRRK2 function result in molecular alterations that ultimately lead to PD. Cellular LRRK2-based models revealed several potential pathophysiological mechanisms including apoptotic cell death, LRRK2 protein accumulation and deficits in neurite outgrowth. However, highly variable outcomes between different cellular models have been reported. Here, we have investigated the effect of different experimental conditions, such as the use of different tags and gene transfer methods, in various cellular LRRK2 models. Readouts included cell death, sensitivity to oxidative stress, LRRK2 relocalization, α-synuclein aggregation and neurite outgrowth in cell culture, as well as neurite maintenance in vivo. We show that overexpression levels and/or the tag fused to LRRK2 affect the relocalization of LRRK2 to filamentous and skein-like structures. We found that overexpression of LRRK2 per se is not sufficient to induce cellular toxicity or to affect α-synuclein-induced toxicity and aggregate formation. Finally, neurite outgrowth/retraction experiments in cell lines and in vivo revealed that secondary, yet unknown, factors are required for the pathogenic LRRK2 effects on neurite length. Our findings stress the importance of technical and biological factors in LRRK2-induced cellular phenotypes and hence imply that conclusions based on these types of LRRK2-based assays should be interpreted with caution.

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Culture Techniques; Cell Line, Tumor; Corpus Striatum; Disease Models, Animal; Female; Gene Knockdown Techniques; Genetic Vectors; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mutation; Neuronal Outgrowth; Neurons; Oxidative Stress; Parkinson Disease; Protein Aggregates; Protein Kinase Inhibitors; Recombinant Proteins; Stereotaxic Techniques

Parkinson's disease (PD) affects millions of patients worldwide and is characterized by alpha-synuclein aggregation in dopamine neurons. Molecular tweezers have shown high potential as anti-aggregation agents targeting positively charged residues of proteins undergoing amyloidogenic processes. Here we report that the molecular tweezer CLR01 decreased aggregation and toxicity in induced pluripotent stem cell-derived dopaminergic cultures treated with PD brain protein extracts. In microfluidic devices CLR01 reduced alpha-synuclein aggregation in cell somas when axonal terminals were exposed to alpha-synuclein oligomers. We then tested CLR01 in vivo in a humanized alpha-synuclein overexpressing mouse model; mice treated at 12 months of age when motor defects are mild exhibited an improvement in motor defects and a decreased oligomeric alpha-synuclein burden. Finally, CLR01 reduced alpha-synuclein-associated pathology in mice injected with alpha-synuclein aggregates into the striatum or substantia nigra. Taken together, these results highlight CLR01 as a disease-modifying therapy for PD and support further clinical investigation.

Topics: alpha-Synuclein; Animals; Bridged-Ring Compounds; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Mice; Organophosphates; Parkinson Disease; Protective Agents; Protein Aggregates

Neurons are dependent on proper trafficking of lipids to neighboring glia for lipid exchange and disposal of potentially lipotoxic metabolites, producing distinct lipid distribution profiles among various cell types of the central nervous system. Little is known of the cellular distribution of neutral lipids in the substantia nigra (SN) of Parkinson's disease (PD) patients and its relationship to inflammatory signaling. This study aimed to determine human PD SN neutral lipid content and distribution in dopaminergic neurons, astrocytes, and microglia relative to age-matched healthy subject controls. The results show that while total neutral lipid content was unchanged relative to age-matched controls, the levels of whole SN triglycerides were correlated with inflammation-attenuating glycoprotein non-metastatic melanoma protein B (GPNMB) signaling in human PD SN. Histological localization of neutral lipids using a fluorescent probe (BODIPY) revealed that dopaminergic neurons and midbrain microglia significantly accumulated intracellular lipids in PD SN, while adjacent astrocytes had a reduced lipid load overall. This pattern was recapitulated by experimental in vivo inhibition of glucocerebrosidase activity in mice. Agents or therapies that restore lipid homeostasis among neurons, astrocytes, and microglia could potentially correct PD pathogenesis and disease progression.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Astrocytes; Case-Control Studies; Cohort Studies; Disease Models, Animal; Dopaminergic Neurons; Female; Glucosylceramidase; Glycolipids; Healthy Volunteers; Humans; Male; Membrane Glycoproteins; Mice; Microglia; Middle Aged; Parkinson Disease; Substantia Nigra; Triglycerides

Parkinson's disease (PD) is a common neurodegenerative disorder with the pathological hallmark of α-synuclein aggregation. Dysregulation of α-synuclein homeostasis caused by aging, genetic, and environmental factors underlies the pathogenesis of PD. While chaperones are essential for proteostasis, whether modulation of cochaperones may participate in PD formation has not been fully characterized. Here, we assessed the expression of several HSP70- and HSP90-related factors under various stresses and found that BAG5 expression is distinctively elevated in etoposide- or H

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Gene Expression Regulation; Humans; Mice; Parkinson Disease; Tumor Suppressor Protein p53

Recent studies have determined that gastrointestinal function contributes to the control of Parkinson's disease (PD). Gastrointestinal dysfunction results in a leaky intestinal barrier, inducing inflammation in the gut. Korean red ginseng (KRG) is widely used for the treatment of numerous afflictions, including inflammation and neurodegenerative disease. We investigated changes in the intestinal tight junctions and proinflammatory cytokines in the colon, and alpha-synuclein (aSyn) in the colon and the substantia nigra (SN) of a PD mouse model. Eight-week-old male C57BL/6 mice were intraperitoneally administered 30 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) once a day for 5 days, and orally given 100 mg/kg of KRG for 12 consecutive days. Alterations in the levels of occludin, zonula occludens-1 (ZO-1), tumor necrosis factor-alpha (TNF-

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Colon; Disease Models, Animal; Inflammation; Male; Mice; Mice, Inbred C57BL; Panax; Parkinson Disease; Plant Preparations; Substantia Nigra; Tight Junctions

Nonmotor symptoms are of pivotal importance in Parkinson's disease (PD), among which depressive disorder occurs in more than 45% of PD cases. Decreased levels of noradrenaline (NA) and serotonin (5-HT) in the central nervous system are relevant to it; however, the underlying mechanism is largely unknown. To this end, we conducted behavioral assays to analyze the depressive phenotype in transgenic mice with overexpressed A53T human α-synuclein (A53T mice) and examined alterations of NAergic and 5-HTergic systems in the neuron degeneration, neurotransmitter production, and degradation aspects of the mouse. As compared to controls, A53T mice displayed elevated depressive-like behavior at 6 months, which presents earlier than motor deficits do at 12 months. We detected reduced levels of NA and 5-HT in the hippocampus and NA in the locus coeruleus of 6-month A53T mice. There was no loss of NAergic and 5-HTergic neurons or decreased neurotransmitter synthesis in the brain. However, the expression of MAO-A, an enzyme responsible for NA and 5-HT degradation, was upregulated in A53T mice. Mechanistically, Sirt1 was downregulated which lead to an increase in FoxO1 acetylation, which subsequently increased the transcription of

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Forkhead Box Protein O1; Humans; Mice; Mice, Transgenic; Monoamine Oxidase; Mutation; Sirtuin 1; Up-Regulation

Idiopathic rapid eye movement sleep behaviour disorder (RBD) is now recognized as an early manifestation of α-synucleinopathies. Increasing experimental studies demonstrate that manipulative lesion or inactivation of the neurons within the sublaterodorsal tegmental nucleus (also known as the subcoeruleus nucleus in humans) can induce RBD-like behaviours in animals. As current RBD animal models are not established on the basis of α-synucleinopathy, they do not represent the pathological substrate of idiopathic RBD and thus cannot model the phenoconversion to Parkinson's disease. The purpose of this study was therefore to establish an α-synucleinopathy-based RBD animal model with the potential to convert to parkinsonian disorder. To this end, we first determined the functional neuroanatomical location of the sublaterodorsal tegmental nucleus in wild-type C57BL/6J mice and then validated its function by recapitulating RBD-like behaviours based on this determined nucleus. Next, we injected preformed α-synuclein fibrils into the sublaterodorsal tegmental nucleus and performed regular polysomnographic recordings and parkinsonian behavioural and histopathological studies in these mice. As a result, we recapitulated RBD-like behaviours in the mice and further showed that the α-synucleinopathy and neuron degeneration identified within the sublaterodorsal tegmental nucleus acted as the neuropathological substrates. Subsequent parkinsonian behavioural studies indicated that the α-synucleinopathy-based RBD mouse model were not stationary, but could further progress to display parkinsonian locomotor dysfunction, depression-like disorder, olfactory dysfunction and gastrointestinal dysmotility. Corresponding to that, we determined α-synuclein pathology in the substantia nigra pars compacta, olfactory bulb, enteral neuroplexus and dorsal motor nucleus of vagus nerve, which could underlie the parkinsonian manifestations in mice. In conclusion, we established a novel α-synucleinopathy-based RBD mouse model and further demonstrated the phenoconversion of RBD to Parkinson's disease in this animal model.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Depression; Disease Models, Animal; Dyskinesias; Electroencephalography; Electromyography; Gastrointestinal Motility; Male; Mice; Mice, Inbred C57BL; Parkinsonian Disorders; Phenotype; Polysomnography; REM Sleep Behavior Disorder; Synucleinopathies

The accumulation of aggregated α-synuclein (αSyn) is a hallmark of Parkinson's disease (PD). Current evidence indicates that small soluble αSyn oligomers (αSynOs) are the most toxic species among the forms of αSyn aggregates, and that size and topological structural properties are crucial factors for αSynOs-mediated toxicity, involving the interaction with either neurons or glial cells. We previously characterized a human αSynO (H-αSynO) with specific structural properties promoting toxicity against neuronal membranes. Here, we tested the neurotoxic potential of these H-αSynOs in vivo, in relation to the neuropathological and symptomatic features of PD. The H-αSynOs were unilaterally infused into the rat substantia nigra pars compacta (SNpc). Phosphorylated αSyn (p129-αSyn), reactive microglia, and cytokine levels were measured at progressive time points. Additionally, a phagocytosis assay in vitro was performed after microglia pre-exposure to αsynOs. Dopaminergic loss, motor, and cognitive performances were assessed. H-αSynOs triggered p129-αSyn deposition in SNpc neurons and microglia and spread to the striatum. Early and persistent neuroinflammatory responses were induced in the SNpc. In vitro, H-αSynOs inhibited the phagocytic function of microglia. H-αsynOs-infused rats displayed early mitochondrial loss and abnormalities in SNpc neurons, followed by a gradual nigrostriatal dopaminergic loss, associated with motor and cognitive impairment. The intracerebral inoculation of structurally characterized H-αSynOs provides a model of progressive PD neuropathology in rats, which will be helpful for testing neuroprotective therapies.

Topics: alpha-Synuclein; Animals; Cytokines; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Inflammation; Male; Microglia; Neurons; Parkinson Disease; Phagocytosis; Phosphorylation; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Substantia Nigra

Type 2 diabetes (T2D), alike Parkinson's disease (PD), belongs to the group of protein misfolding diseases (PMDs), which share aggregation of misfolded proteins as a hallmark. Although the major aggregating peptide in β-cells of T2D patients is Islet Amyloid Polypeptide (IAPP), alpha-synuclein (αSyn), the aggregating peptide in substantia nigra neurons of PD patients, is expressed also in β-cells. Here we show that αSyn, encoded by Snca, is a component of amyloid extracted from pancreas of transgenic mice overexpressing human IAPP (denoted hIAPPtg mice) and from islets of T2D individuals. Notably, αSyn dose-dependently promoted IAPP fibril formation in vitro and tail-vein injection of αSyn in hIAPPtg mice enhanced β-cell amyloid formation in vivo whereas β-cell amyloid formation was reduced in hIAPPtg mice on a Snca

Topics: alpha-Synuclein; Amyloid; Animals; Diabetes Mellitus, Type 2; Disease Models, Animal; Humans; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Mice; Mice, Transgenic; Protein Aggregates

Functional foods enriched with plant polyphenols and anthocyanins in particular attract special attention due to multiple beneficial bioactive properties of the latter. We evaluated the effects of a grain diet rich in anthocyanins in a mouse model of Alzheimer's disease induced by amyloid-beta (Aβ) and a transgenic mouse model of Parkinson's disease (PD) with overexpression of human alpha-synuclein. The mice were kept at a diet that consisted of the wheat grain of near isogenic lines differing in anthocyanin content for five-six months. The anthocyanin-rich diet was safe and possessed positive effects on cognitive function. Anthocyanins prevented deficits in working memory induced by Aβ or a long-term grain mono-diet; they partially reversed episodic memory alterations. Both types of grain diets prolonged memory extinction and rescued its facilitation in the PD model. The dynamics of the extinction in the group fed with the anthocyanin-rich wheat was closer to that in a group of wild-type mice given standard chow. The anthocyanin-rich diet reduced alpha-synuclein accumulation and modulated microglial response in the brain of the transgenic mice including the elevated expression of arginase1 that marks M2 microglia. Thus, anthocyanin-rich wheat is suggested as a promising source of functional nutrition at the early stages of neurodegenerative disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Analysis of Variance; Animals; Anthocyanins; Arginase; Avoidance Learning; Disease Models, Animal; Food, Fortified; Functional Food; Male; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Neurodegenerative Diseases; Open Field Test; Parkinson Disease; Triticum; Weight Gain

Parkinson's disease (PD) is a common neurodegenerative disorder involving α-synuclein (α-syn) aggregation, oxidative stress, dysregulation of redox metal homeostasis, and neurotoxicity. Different phenolic compounds with known antioxidant or antichelating properties have been shown to also interfere with aggregation of amyloid proteins and modulate intracellular signaling pathways. The present study aims to investigate for the first time the effect of tyrosol (TYR), a simple phenol present in extra-virgin olive oil, on α-syn aggregation in a Caenorhabditis elegans model of PD and evaluate its potential to prevent α-syn toxicity, neurodegeneration, and oxidative stress in this model organism. Our results show that TYR is effective in reducing α-syn inclusions, resulting in a lower toxicity and extended life span of treated nematodes. Moreover, TYR delayed α-syn-dependent degeneration of dopaminergic neurons in vivo. TYR treatment also reduced reactive oxygen species level and promoted the expression of specific chaperones and antioxidant enzymes. Overall, our study puts into perspective TYR potential to be considered as nutraceutical that targets pivotal causal factors in PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antioxidants; Caenorhabditis elegans; Dietary Supplements; Disease Models, Animal; Drug Delivery Systems; Nerve Degeneration; Olive Oil; Parkinsonian Disorders; Phenylethyl Alcohol

Cell-to-cell propagation of α-synuclein (α-syn) aggregates is thought to contribute to the pathogenesis of Parkinson's disease (PD) and underlie the spread of α-syn neuropathology. Increased pro-inflammatory cytokine levels and activated microglia are present in PD and activated microglia can promote α-syn aggregation. However, it is unclear how microglia influence α-syn cell-to-cell transfer.. We developed a clinically relevant mouse model to monitor α-syn prion-like propagation between cells; we transplanted wild-type mouse embryonic midbrain neurons into a mouse striatum overexpressing human α-syn (huα-syn) following adeno-associated viral injection into the substantia nigra. In this system, we depleted or activated microglial cells and determined the effects on the transfer of huα-syn from host nigrostriatal neurons into the implanted dopaminergic neurons, using the presence of huα-syn within the grafted cells as a readout.. First, we compared α-syn cell-to-cell transfer between host mice with a normal number of microglia to mice in which we had pharmacologically ablated 80% of the microglia from the grafted striatum. With fewer host microglia, we observed increased accumulation of huα-syn in grafted dopaminergic neurons. Second, we assessed the transfer of α-syn into grafted neurons in the context of microglia activated by one of two stimuli, lipopolysaccharide (LPS) or interleukin-4 (IL-4). LPS exposure led to a strong activation of microglial cells (as determined by microglia morphology, cytokine production and an upregulation in genes involved in the inflammatory response in the LPS-injected mice by RNA sequencing analysis). LPS-injected mice had significantly higher amounts of huα-syn in grafted neurons. In contrast, injection of IL-4 did not change the proportion of grafted dopamine neurons that contained huα-syn relative to controls. As expected, RNA sequencing analysis on striatal tissue revealed differential gene expression between LPS and IL-4-injected mice; with the genes upregulated in tissue from mice injected with LPS including several of those involved in an inflammatory response.. The absence or the hyperstimulation of microglia affected α-syn transfer in the brain. Our results suggest that under resting, non-inflammatory conditions, microglia modulate the transfer of α-syn. Pharmacological regulation of neuroinflammation could represent a future avenue for limiting the spread of PD neuropathology.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopaminergic Neurons; Female; Lipopolysaccharides; Macrophages; Mice, Inbred C57BL; Microglia; Nerve Degeneration; Parkinson Disease

Many neurodegenerative diseases are characterized by the accumulation of abnormal protein aggregates in the brain. In Parkinson's disease (PD), α-synuclein (α-syn) forms such aggregates called Lewy bodies (LBs). Recently, it has been reported that aggregates of α-syn with a cross-β structure are capable of propagating within the brain in a prionlike manner. However, the presence of cross-β sheet-rich aggregates in LBs has not been experimentally demonstrated so far. Here, we examined LBs in thin sections of autopsy brains of patients with PD using microbeam X-ray diffraction (XRD) and found that some of them gave a diffraction pattern typical of a cross-β structure. This result confirms that LBs in the brain of PD patients contain amyloid fibrils with a cross-β structure and supports the validity of in vitro propagation experiments using artificially formed amyloid fibrils of α-syn. Notably, our finding supports the concept that PD is a type of amyloidosis, a disease featuring the accumulation of amyloid fibrils of α-syn.

Topics: alpha-Synuclein; Amyloid; Amyloidosis; Animals; Brain; Disease Models, Animal; Disease Susceptibility; Humans; Lewy Bodies; Mice; Parkinson Disease; Plaque, Amyloid; X-Ray Diffraction

The synucleinopathies Parkinson's disease (PD) and Multiple system atrophy (MSA) - characterized by α-synuclein intracytoplasmic inclusions into, respectively, neurons and oligodendrocytes - are associated with impairment of the autophagy-lysosomal pathways (ALP). Increased expression of the master regulator of ALP, transcription factor EB (TFEB), is hypothesized to promote the clearance of WT α-synuclein and survival of dopaminergic neurons. Here, we explore the efficacy of targeted TFEB overexpression either in neurons or oligodendrocytes to reduce the pathological burden of α-synuclein in a PD rat model and a MSA mouse model. While TFEB neuronal expression was sufficient to prevent neurodegeneration in the PD model, we show that only TFEB oligodendroglial overexpression leads to neuroprotective effects in the MSA model. These beneficial effects were associated with a decreased accumulation of α-synuclein into oligodendrocytes through recovery of the ALP machinery. Our study demonstrates that the cell type where α-synuclein aggregates dictates the target of TFEB overexpression in order to be protective, paving the way for adapted therapies.

Topics: Aged; alpha-Synuclein; Animals; Autophagy; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Brain; Cell Line, Tumor; Disease Models, Animal; HEK293 Cells; Humans; Male; Mice; Mice, Inbred C57BL; Multiple System Atrophy; Oligodendroglia; Parkinson Disease; Rats; Rats, Sprague-Dawley

Parkinson's disease is a neurodegenerative movement disorder; however, peripheral symptoms can arise decades prior. In this issue of Neuron, Kim et al. (2019) provide evidence that progressive α-synuclein aggregation initiating in the gut could be a pathogenic epicenter anatomically rippling throughout the nervous system.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Neurodegenerative Diseases; Parkinson Disease

Cortical α-synuclein pathology plays a role in the development of cognitive dysfunction in both Parkinson's disease and dementia with Lewy bodies, although the causative cellular lesions have remained unclear. We aimed to address causal links between α-synuclein-driven pathology in the cerebral cortex and the development of cognitive impairments using new experimental models.. Neuronal overexpression of human α-synuclein was induced in the rat medial prefrontal cortex using viral vectors. This was combined with inoculations of preformed fibrils of human α-synuclein in some animals. Rats were evaluated with tests probing prefrontal cognitive functions (delayed matching/nonmatching to position and 5-choice serial reaction time task). Patterns of neuropathology were characterized immunohistochemically.. Neither α-synuclein overexpression nor the fibril seeds alone yielded any behavioral phenotype. In contrast, combining the 2 approaches produced significant impairments in working memory, attention, and inhibitory control. All animals injected with α-synuclein vectors exhibited high immunoreactivity for human α-synuclein in the medial prefrontal cortex and its primary projection targets. However, only when this overexpression was combined with fibril inoculations did animals exhibit large, proteinase K-resistant and Ser. Cortical overexpression of human α-synuclein is not sufficient to produce cognitive dysfunction, whereas combining this overexpression with fibril seeds yields both cognitive and histopathological phenotypes that are relevant to human Lewy body disease. © 2019 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Cognitive Dysfunction; Disease Models, Animal; Lewy Bodies; Lewy Body Disease; Neurons; Parkinson Disease; Parkinsonian Disorders; Protein Aggregates; Rats; Synaptic Transmission

Cognitive decline and dementia in neurodegenerative diseases are associated with synapse dysfunction and loss, which may precede neuron loss by several years. While misfolded and aggregated α-synuclein is recognized in the disease progression of synucleinopathies, the nature of glutamatergic synapse dysfunction and loss remains incompletely understood. Using fluorescence-activated synaptosome sorting (FASS), we enriched excitatory glutamatergic synaptosomes from mice overexpressing human alpha-synuclein (h-αS) and wild-type littermates to unprecedented purity. Subsequent label-free proteomic quantification revealed a set of proteins differentially expressed upon human alpha-synuclein overexpression. These include overrepresented proteins involved in the synaptic vesicle cycle, ER-Golgi trafficking, metabolism and cytoskeleton. Unexpectedly, we found and validated a steep reduction of eukaryotic translation elongation factor 1 alpha (eEF1A1) levels in excitatory synapses at early stages of h-αS mouse model pathology. While eEF1A1 reduction correlated with the loss of postsynapses, its immunoreactivity was found on both sides of excitatory synapses. Moreover, we observed a reduction in eEF1A1 immunoreactivity in the cingulate gyrus neuropil of patients with Lewy body disease along with a reduction in PSD95 levels. Altogether, our results suggest a link between structural impairments underlying cognitive decline in neurodegenerative disorders and local synaptic defects. eEF1A1 may therefore represent a limiting factor to synapse maintenance.

Topics: alpha-Synuclein; Animals; Cerebral Cortex; Computational Biology; Disease Models, Animal; Disks Large Homolog 4 Protein; Female; Male; Mice, Transgenic; Neuropil; Peptide Elongation Factor 1; Proteome; Synapses; Synucleinopathies

Neuroinflammation is one of the hallmarks of Parkinson's disease (PD) and may contribute to midbrain dopamine (DA) neuron degeneration. Recent studies link chronic inflammation with failure to resolve early inflammation, a process operated by specialized pro-resolving mediators, including resolvins. However, the effects of stimulating the resolution of inflammation in PD - to modulate disease progression - still remain unexplored. Here we show that rats overexpressing human α-synuclein (Syn) display altered DA neuron properties, reduced striatal DA outflow and motor deficits prior to nigral degeneration. These early alterations are coupled with microglia activation and perturbations of inflammatory and pro-resolving mediators, namely IFN-γ and resolvin D1 (RvD1). Chronic and early RvD1 administration in Syn rats prevents central and peripheral inflammation, as well as neuronal dysfunction and motor deficits. We also show that endogenous RvD1 is decreased in human patients with early-PD. Our results suggest there is an imbalance between neuroinflammatory and pro-resolving processes in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Docosahexaenoic Acids; Dopaminergic Neurons; Humans; Inflammation; Male; Microglia; Nerve Degeneration; Parkinson Disease; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Substantia Nigra

The development of new therapies to slow down or halt the progression of Parkinson's disease is a health care priority. A key pathological feature is the presence of alpha-synuclein aggregates, and there is increasing evidence that alpha-synuclein propagation plays a central role in disease progression. Consequently, the downregulation of alpha-synuclein is a potential therapeutic target. As a chronic disease, the ideal treatment will be minimally invasive and effective in the long-term. Knockdown of gene expression has clear potential, and siRNAs specific to alpha-synuclein have been designed; however, the efficacy of siRNA treatment is limited by its short-term efficacy. To combat this, we designed shRNA minicircles (shRNA-MCs), with the potential for prolonged effectiveness, and used RVG-exosomes as the vehicle for specific delivery into the brain. We optimized this system using transgenic mice expressing GFP and demonstrated its ability to downregulate GFP protein expression in the brain for up to 6 weeks. RVG-exosomes were used to deliver anti-alpha-synuclein shRNA-MC therapy to the alpha-synuclein preformed-fibril-induced model of parkinsonism. This therapy decreased alpha-synuclein aggregation, reduced the loss of dopaminergic neurons, and improved the clinical symptoms. Our results confirm the therapeutic potential of shRNA-MCs delivered by RVG-exosomes for long-term treatment of neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Drug Delivery Systems; Exosomes; Gene Expression Regulation; Genetic Therapy; Humans; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; RNA, Small Interfering

Synucleinopathies are composed of Parkinson disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Alpha-synuclein (α-Syn) forms aggregates mainly in neurons in PD and DLB, while oligodendroglial α-Syn aggregates are characteristic of MSA. Recent studies have demonstrated that injections of synthetic α-Syn preformed fibrils (PFFs) into the brains of wild-type (WT) animals induce intraneuronal α-Syn aggregates and the subsequent interneuronal transmission of α-Syn aggregates. However, injections of α-Syn PFFs or even brain lysates of patients with MSA have not been reported to induce oligodendroglial α-Syn aggregates, raising questions about the pathogenesis of oligodendroglial α-Syn aggregates in MSA. Here, we report that WT mice injected with mouse α-Syn (m-α-Syn) PFFs develop neuronal α-Syn pathology after short postinjection (PI) intervals on the scale of weeks, while oligodendroglial α-Syn pathology emerges after longer PI intervals of several months. Abundant oligodendroglial α-Syn pathology in white matter at later time points is reminiscent of MSA. Furthermore, comparison between young and aged mice injected with m-α-Syn PFFs revealed that PI intervals rather than aging correlate with oligodendroglial α-Syn aggregation. These results provide novel insights into the pathological mechanisms of oligodendroglial α-Syn aggregation in MSA.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Disease Progression; Male; Mice; Neurons; Oligodendroglia; Synucleinopathies; White Matter

Microglia-mediated neuroinflammation is critical for the pathogenesis of neurodegenerative diseases, including Parkinson's disease (PD). microRNA-let-7a (miR-let-7a) targets the signal transducer and activator of transcription-3 (STAT3) and regulates microglia function. However, less is known about whether it plays a functional role in PD. In this report, by utilizing a mouse PD model induced by the overexpression of α-Synuclein (α-Syn), a pathological hallmark of PD, we found that miR-let-7a expression was downregulated, while STAT3 was synchronously activated in the substantia nigra pars compacta (SNpc). Similar results were obtained in α-Syn-treated BV-2 microglia cells cultured in vitro. Additionally, STAT3 was proven to be a direct target of miR-let-7a in BV-2 microglia cells, suggesting that miR-let-7a downregulation may contribute to STAT3 activation in α-Syn-induced mouse PD. Moreover, miR-let-7a overexpression suppressed α-Syn-induced BV-2 microglia cell activation and pro-inflammatory cytokine production, and these effects were abrogated by restoring STAT3 protein, hence establishing that miR-let-7a suppresses microglia-mediated inflammation through targeting STAT3. Lastly, miR-let-7a overexpression via injection of miR-7 mimics into mouse striatum suppressed microglia activation and reduced pro-inflammatory cytokine production, which were accompanied by relieved movement disorder and improved spatial memory deficits in α-Syn-induced PD mice. Altogether, these results may identify miR-let-7a as a negative regulator of microglia-elicited neuroinflammation, at least partially explaining its alleviating effects on PD symptoms.

Topics: 3' Untranslated Regions; alpha-Synuclein; Animals; Disease Models, Animal; Gene Expression Regulation; Humans; Inflammation; Male; Memory Disorders; Mice, Inbred C57BL; Microglia; MicroRNAs; Movement Disorders; Parkinson Disease; STAT3 Transcription Factor

Debilitating, yet underinvestigated nonmotor symptoms related to mood/emotion, such as depression, are common in Parkinson's disease. Here, we explore the role of depression and of the amygdala, a brain region robustly linked to mood/emotion, in synucleinopathy. We hypothesized that mood/emotional deficits might accelerate Parkinson's disease-linked symptomatology, including the formation of α-synuclein pathology. We combined elevated corticosterone treatment, modeling chronic stress and depression, with a model of seeded α-synuclein pathology in mouse striatum and assessed behavioral parameters with a focus on mood/emotion, and neuropathology. We report behavioral resilience against α-synuclein proteinopathy in the absence of additional insults, potentially based on hormesis/conditioning mechanisms. Elevated corticosterone, however, reversed α-synuclein pathology-induced behavioral adaptations and was associated with increased dopaminergic cell loss as well as aggravated α-synuclein pathology in specific brain regions, such as the entorhinal cortex. These findings point to elevated glucocorticoids as a risk factor for Parkinson's disease progression and highlight the potential of glucocorticoid level reducing strategies to slow down disease progression in synucleinopathy.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Corticosterone; Disease Models, Animal; Dopaminergic Neurons; Male; Mice, Inbred C57BL; Parkinson Disease; Synucleinopathies

Mutations in CHCHD2 are linked to a familial, autosomal dominant form of Parkinson's disease (PD). The gene product may regulate mitochondrial respiratory function. However, whether mitochondrial dysfunction induced by CHCHD2 mutations further yields α-synuclein pathology is unclear. Here, we provide compelling genetic evidence that mitochondrial dysfunction induced by PD-linked CHCHD2 T61I mutation promotes α-synuclein aggregation using brain autopsy, induced pluripotent stem cells (iPSCs) and Drosophila genetics. An autopsy of an individual with CHCHD2 T61I revealed widespread Lewy pathology with both amyloid plaques and neurofibrillary tangles that appeared in the brain stem, limbic regions and neocortex. A prominent accumulation of sarkosyl-insoluble α-synuclein aggregates, the extent of which was comparable to that of a case with α-synuclein (SNCA) duplication, was observed in CHCHD2 T61I brain tissue. The prion-like activity and morphology of α-synuclein fibrils from the CHCHD2 T61I brain tissue were similar to those of fibrils from SNCA duplication and sporadic PD brain tissues. α-Synuclein insolubilization was reproduced in dopaminergic neuron cultures from CHCHD2 T61I iPSCs and Drosophila lacking the CHCHD2 ortholog or expressing the human CHCHD2 T61I. Moreover, the combination of ectopic α-synuclein expression and CHCHD2 null or T61I enhanced the toxicity in Drosophila dopaminergic neurons, altering the proteolysis pathways. Furthermore, CHCHD2 T61I lost its mitochondrial localization by α-synuclein in Drosophila. The mislocalization of CHCHD2 T61I was also observed in the patient brain. Our study suggests that CHCHD2 is a significant mitochondrial factor that determines α-synuclein stability in the etiology of PD.

Topics: Aged; alpha-Synuclein; Animals; Autopsy; Brain; Cells, Cultured; Disease Models, Animal; DNA-Binding Proteins; Drosophila; Female; Humans; Loss of Function Mutation; Male; Middle Aged; Mitochondria; Neurons; Parkinson Disease; Pedigree; Protein Aggregates; Protein Stability; Transcription Factors

Aggregation of alpha-synuclein (α-SYN) is the pathological hallmark of several diseases named synucleinopathies, including Parkinson's disease (PD), which is the most common neurodegenerative motor disorder. Alpha-SYN has been linked to synaptic function both in physiological and pathological conditions. However, the exact link between neuronal activity, α-SYN toxicity and disease progression in PD is not clear. In this study, we aimed to investigate the effect of chronic neuromodulation in an α-SYN-based rat model for PD using chemogenetics. To do this, we expressed excitatory Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) combined with mutant A53T α-SYN, using two different recombinant adeno-associated viral (rAAV) vectors (serotypes 2/7 and 2/8) in rat substantia nigra (SN) and investigated the effect on motor behavior, synapses and neuropathology. We found that chronic neuromodulation aggravates motor deficits induced by α-SYN, without altering dopaminergic neurodegeneration. In addition, neuronal activation led to changes in post-translational modification and subcellular localization of α-SYN, linking neuronal activity to the pathophysiological role of α-SYN in PD.

Topics: Action Potentials; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Female; Neurons; Parkinson Disease; Rats, Wistar; Substantia Nigra; Synapses

Abnormal aggregation of misfolded pathological proteins in neurons is a prominent feature of neurodegenerative disorders including Parkinson's disease (PD). Perturbations of proteostasis at the endoplasmic reticulum (ER) triggers ER stress, activating the unfolded protein response (UPR). Chronic ER stress is thought to underlie the death of neurons during the neurodegenerative progression, but the precise mechanism by which the UPR pathways regulate neuronal cell fate remains incompletely understood. Here we report a critical neurodegenerative role for inositol-requiring enzyme 1 (IRE1), the evolutionarily conserved ER stress sensor, in a Drosophila model of PD. We found that IRE1 was hyperactivated upon accumulation of α-synuclein in the fly photoreceptor neurons. Ectopic overexpression of IRE1 was sufficient to trigger autophagy-dependent neuron death in an XBP1-independent, JNK-dependent manner. Furthermore, IRE1 was able to promote dopaminergic neuron loss, progressive locomotor impairment, and shorter lifespan, whereas blocking IRE1 or ATG7 expression remarkably ameliorated the progression of α-synuclein-caused Parkinson's disease. These results provide in vivo evidence demonstrating that the IRE1 pathway drives PD progression through coupling ER stress to autophagy-dependent neuron death.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Endoplasmic Reticulum Stress; Endoribonucleases; Humans; Neurons; Parkinson Disease; Signal Transduction

This study explored the influence of long non-coding RNA (lncRNA) SNHG14 on α-synuclein (α-syn) expression and Parkinson's disease (PD) pathogenesis. Firstly, we found that the expression level of SNHG14 was elevated in brain tissues of PD mice. In MN9D cells, the rotenone treatment (1μmol/L) enhanced the binding between transcriptional factor SP-1 and SNHG14 promoter, thus promoting SNHG14 expression. Interference of SNHG14 ameliorated the DA neuron injury induced by rotenone. Next, we found an interaction between SNHG14 and miR-133b. Further study showed that miR-133b down-regulated α-syn expression by targeting its 3'-UTR of mRNA and SNHG14 could reverse the negative effect of miR-133b on α-syn expression. Interference of SNHG14 reduced rotenone-induced DA neuron damage through miR-133b in MN9D cells and α-syn was responsible for the protective effect of miR-133b. Similarly, interference of SNHG14 mitigated neuron injury in PD mouse model. All in all, silence of SNHG14 mitigates dopaminergic neuron injury by down-regulating α-syn via targeting miR-133b, which contributes to improving PD.

Topics: alpha-Synuclein; Animals; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Intracellular Signaling Peptides and Proteins; Mice, Inbred C57BL; MicroRNAs; Nerve Tissue Proteins; Parkinson Disease, Secondary; RNA, Long Noncoding; Rotenone

Parkinson's disease is characterized by the aggregation of the presynaptic protein α-synuclein and its deposition into pathologic Lewy bodies. While extensive research has been carried out on mediators of α-synuclein aggregation, molecular facilitators of α-synuclein disaggregation are still generally unknown. We investigated the role of molecular chaperones in both preventing and disaggregating α-synuclein oligomers and fibrils, with a focus on the mammalian disaggregase complex. Here, we show that overexpression of the chaperone Hsp110 is sufficient to reduce α-synuclein aggregation in a mammalian cell culture model. Additionally, we demonstrate that Hsp110 effectively mitigates α-synuclein pathology in vivo through the characterization of transgenic Hsp110 and double-transgenic α-synuclein/Hsp110 mouse models. Unbiased analysis of the synaptic proteome of these mice revealed that overexpression of Hsp110 can override the protein changes driven by the α-synuclein transgene. Furthermore, overexpression of Hsp110 is sufficient to prevent endogenous α-synuclein templating and spread following injection of aggregated α-synuclein seeds into brain, supporting a role for Hsp110 in the prevention and/or disaggregation of α-synuclein pathology.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Green Fluorescent Proteins; HEK293 Cells; HSP110 Heat-Shock Proteins; Humans; Mice, Transgenic; Parkinson Disease; Spinal Cord; Synucleinopathies

The human A53T mutant of α-synuclein tends to aggregate and leads to neurotoxicity in familial Parkinson's disease (PD). The aggregation of α-synuclein is also found in sporadic PD. Thus, targeting α-synuclein clearance could be used as a drug-discovery strategy for PD treatment. Caffeic acid (CA) has shown neuroprotection in Alzheimer's disease or cerebral ischaemia; however, it is unclear whether CA confers neuroprotection in α-synuclein-induced PD models. Here we focus on whether and how A53T α-synuclein is affected by CA. We assessed the effect of CA on cell viability in SH-SY5Y cells overexpressing A53T α-synuclein. Pathway-related inhibitors were used to identify the autophagy mechanisms. Seven-month-old A53T α-synuclein transgenic mice (A53T Tg mice) received CA daily for eight consecutive weeks. Behaviour tests including the buried food pellet test, the pole test, the Rotarod test, open field analysis, and gait analysis were used to evaluate the neuroprotective effect of CA. Tyrosine hydroxylase and α-synuclein were assessed by immunohistochemistry or western blot in the substantia nigra (SN). We found that CA alleviated the cell damage induced by overexpressing A53T α-synuclein and that CA reduced A53T α-synuclein by activating the JNK/Bcl-2-mediated autophagy pathway. The efficacy of CA on A53T α-synuclein degradation was reversed by the autophagy inhibitor bafilomycin A1 and the JNK inhibitor SP600125. In A53T Tg mice, CA improved behavioural impairments, attenuated loss of dopaminergic neurons, enhanced autophagy and reduced α-synuclein in the SN. Thus, the results provide scientific evidence for the neuroprotective effect of CA in PD. Our work lays the foundation for CA clinical trials to treat PD in the future.

Topics: alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Brain; Caffeic Acids; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Gait; Humans; Male; MAP Kinase Kinase 4; Mice, Transgenic; Neuroprotective Agents; Parkinson Disease; Parkinsonian Disorders; Proto-Oncogene Proteins c-bcl-2

The pathogenesis of synucleinopathies, common neuropathological lesions normally associated with some human neurodegenerative disorders such as Parkinson's disease, dementia with Lewy bodies and multiple system atrophy, remains poorly understood. In animals, ingestion of the tryptamine-alkaloid-rich phalaris pastures plants causes a disorder called Phalaris staggers, a neurological syndrome reported in kangaroos. The aim of the study was to characterise the clinical and neuropathological changes associated with spontaneous cases of Phalaris staggers in kangaroos. Gross, histological, ultrastructural and Immunohistochemical studies were performed to demonstrate neuronal accumulation of neuromelanin and aggregated α-synuclein. ELISA and mass spectrometry were used to detect serum-borne α-synuclein and tryptamine alkaloids respectively. We report that neurons in the central and enteric nervous systems of affected kangaroos display extensive accumulation of neuromelanin in the perikaryon without affecting neuronal morphology. Ultrastructural studies confirmed the typical structure of neuromelanin. While we demonstrated strong staining of α-synuclein, restricted to neurons, intracytoplasmic Lewy bodies inclusions were not observed. α-synuclein aggregates levels were shown to be lower in sera of the affected kangaroos compared to unaffected herd mate kangaroos. Finally, mass spectrometry failed to detect the alkaloid toxins in the sera derived from the affected kangaroos. Our preliminary findings warrant further investigation of Phalaris staggers in kangaroos, potentially a valuable large animal model for environmentally-acquired toxic synucleinopathy.

Topics: Alkaloids; alpha-Synuclein; Animals; Disease Models, Animal; Female; Macropodidae; Male; Mass Spectrometry; Melanins; Neurons; Phalaris; Plant Extracts; Protein Aggregates; Synucleinopathies; Tryptamines

Plethora of efforts fails to yield a single drug to reverse the pathogenesis of Parkinson's disease (PD) and related α-synucleopathies.. Using chemical biology, we identified a small molecule inhibitor of c-abl kinase, PD180970 that could potentially clear the toxic protein aggregates. Genetic, molecular, cell biological and immunological assays were performed to understand the mechanism of action. In vivo preclinical disease model of PD was used to assess its neuroprotection efficacy.. In this report, we show the ability of a small molecule inhibitor of tyrosine kinases, PD180970, to induce autophagy (cell lines and mice midbrain) in an mTOR-independent manner and ameliorate the α-synuclein mediated toxicity. PD180970 also exerts anti-neuroinflammatory potential by inhibiting the release of proinflammatory cytokines such as IL-6 (interleukin-6) and MCP-1 (monocyte chemoattractant protein-1) through reduction of TLR-4 (toll like receptor-4) mediated NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation. In vivo studies show that PD180970 is neuroprotective by degrading the toxic protein oligomers through induction of autophagy and subsiding the microglial activation.. These protective mechanisms ensure the negation of Parkinson's disease related motor impairments. FUND: This work was supported by Wellcome Trust/DBT India Alliance Intermediate Fellowship (500159-Z-09-Z), DST-SERB grant (EMR/2015/001946), DBT (BT/INF/22/SP27679/2018) and JNCASR intramural funds to RM, and SERB, DST (SR/SO/HS/0121/2012) to PAA, and DST-SERB (SB/YS/LS-215/2013) to JPC and BIRAC funding to ETA C-CAMP.

Topics: alpha-Synuclein; Animals; Biomarkers; Cell Line; Cytokines; Disease Models, Animal; Humans; Immunohistochemistry; Interleukin-6; Lipopolysaccharides; Macroautophagy; Male; Mice; Microglia; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Oxidative Stress; Protein Aggregates; Protein Aggregation, Pathological; Pyridones; Pyrimidines

Alpha-synuclein (α-syn) is an abundant neuroprotein elevated in cocaine addicts, linked to drug craving, and recruited to axon terminals undergoing glutamatergic plasticity - a proposed mechanism for substance abuse. However, little is known about normal α-syn function or how it contributes to substance abuse. We show that α-syn is critical for preference of hedonic stimuli and the cognitive flexibility needed to change behavioral strategies, functions that are altered with substance abuse. Electron microscopic analysis reveals changes in α-syn targeting of ventral tegmental area axon terminals that is dependent upon the duration of cocaine exposure. The dynamic changes in presynaptic α-syn position it to control neurotransmission and fine-tune the complex afferent inputs to dopamine neurons, potentially altering functional dopamine output. Cocaine also increases postsynaptic α-syn where it is needed for normal ALIX function, multivesicular body formation, and cocaine-induced exosome release indicating potentially similar α-syn actions for vesicle release pre- and post-synaptically.

Topics: alpha-Synuclein; Animals; Cocaine; Cocaine-Related Disorders; Disease Models, Animal; Disease Susceptibility; Dopaminergic Neurons; Extracellular Space; Immunohistochemistry; Male; Mesencephalon; Mice; Mice, Knockout; Models, Biological; Motivation; Motor Activity; Reward; Signal Transduction

Alpha-synuclein (aSyn) is the main component of Lewy bodies, the histopathological marker in Parkinson's disease (PD), and point mutations and multiplications of the aSyn coding SNCA gene correlate with early onset PD. Therefore, various transgenic mouse models overexpressing native or point-mutated aSyn have been developed. Although these models show highly increased aSyn expression they rarely capture dopaminergic cell loss and show a behavioural phenotype only at old age, whereas SNCA mutations are risk factors for PD with earlier onset. The aim of our study was to re-characterize a transgenic mouse strain carrying both A30P and A53T mutated human aSyn. Our study revealed decreased locomotor activity for homozygous transgenic mice starting from 3 months of age which was different from previous studies with this mouse strain that had behavioural deficits starting only after 7-9 months. Additionally, we found a decreased amphetamine response in locomotor activity and decreased extracellular dopaminergic markers in the striatum and substantia nigra with significantly elevated levels of aSyn oligomers. In conclusion, homozygous transgenic A30P*A53T aSyn mice capture several phenotypes of PD with early onset and could be a useful tool for aSyn studies.

Topics: Aging; Alanine; alpha-Synuclein; Amino Acid Substitution; Animals; Behavior, Animal; Disease Models, Animal; Dopaminergic Neurons; Humans; Locomotion; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation, Missense; Parkinson Disease; Proline; Threonine

Intracellular accumulation of α-synuclein (α-syn) and formation of Lewy bodies are neuropathological characteristics of Parkinson's disease (PD) and related α-synucleinopathies. Oligomerization and spreading of α-syn from neuron to neuron have been suggested as key events contributing to the progression of PD. To directly visualize and characterize α-syn oligomerization and spreading in vivo, we generated two independent conditional transgenic mouse models based on α-syn protein complementation assays using neuron-specifically expressed split Gaussia luciferase or split Venus yellow fluorescent protein (YFP). These transgenic mice allow direct assessment of the quantity and subcellular distribution of α-syn oligomers in vivo. Using these mouse models, we demonstrate an age-dependent accumulation of a specific subtype of α-syn oligomers. We provide in vivo evidence that, although α-syn is found throughout neurons, α-syn oligomerization takes place at the presynapse. Furthermore, our mouse models provide strong evidence for a transsynaptic cell-to-cell transfer of de novo generated α-syn oligomers in vivo.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Neurons; Parkinson Disease

Mitochondrial degeneration is considered one of the major causes of Parkinson's disease (PD). Improved mitochondrial functions are expected to be a promising therapeutic strategy for PD. In this study, we introduced a light-driven proton transporter, Delta-rhodopsin (dR), to

Topics: alpha-Synuclein; Animals; Biomarkers; Disease Models, Animal; Disease Susceptibility; Dopaminergic Neurons; Drosophila; Light; Mitochondria; Mitochondrial Diseases; Models, Biological; Motor Activity; Oxidative Stress; Parkinson Disease; Protons; Reactive Oxygen Species

Given the recent in vitro discovery that the free soluble oligosaccharide of GM1 is the bioactive portion of GM1 for neurotrophic functions, we investigated its therapeutic potential in the B4galnt1

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Hand Strength; Male; Mice, Inbred C57BL; Motor Activity; N-Acetylgalactosaminyltransferases; Neurotransmitter Agents; Oligosaccharides; Parkinson Disease; Substantia Nigra; Tyrosine 3-Monooxygenase

A significant number of people with Parkinson's disease (PD) develop dementia in addition to cognitive dysfunction and are diagnosed as PD with dementia (PDD). This is characterized by cortical and limbic alpha synuclein (α-syn) accumulation, and high levels of diffuse amyloid beta (Aβ) plaques in the striatum and neocortical areas. In this regard, we evaluated the effect of a brain-penetrant, novel multifunctional dopamine D2/D3 agonist, D-520 on the inhibition of Aβ aggregation and disintegration of α-syn and Aβ aggregates in vitro using purified proteins and in a cell culture model that produces intracellular Aβ-induced toxicity. We further evaluated the effect of D-520 in a Drosophila model of Aβ

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Dementia; Disease Models, Animal; Dopamine Agonists; Drosophila melanogaster; Drug Delivery Systems; Humans; Parkinson Disease; PC12 Cells; Peptide Fragments; Rats; Receptors, Dopamine D2; Receptors, Dopamine D3

Alpha-synuclein (α-syn) aggregation is a neuropathological hallmark of neurodegenerative synucleinopathies. This in vivo study explored glucose metabolism and dopaminergic and serotoninergic neurotransmission in KO α-syn, wild-type mice and an accelerated murine model of synucleinopathy (M83).. MicroPET acquisitions were performed in all animals aged 5-6 months using five radiotracers exploring brain glucose metabolism ([. MicroPET data showed a decrease in [. This PET study highlights an effect of α-syn modulation on the expression of the D

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Female; Male; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Positron-Emission Tomography; Radiopharmaceuticals; Serotonin; Synaptic Transmission

Parkinson's disease (PD) is the second-most common neurodegenerative disorder and is characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Oxidative stress has also been linked with the progression of PD, hence the involvement of a natural plant product could offer neuroprotection. The present study deals with the effect of genistein on the transgenic flies expressing normal human alpha synuclein panneurally. The PD flies were exposed to 10, 20, 30, and 40 µM of genistein (mixed in diet) for 24 days. A significant dose-dependent increase in the life span and delay in the loss of climbing ability were observed in the PD flies exposed to genistein (

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Dopamine; Drosophila; Gene Expression; Genistein; Humans; Locomotion; Monoamine Oxidase; Neurons; Parkinson Disease

This study investigated the effects of ferulic acid (FR), muscle exercise (Ex) and combination of them on rotenone (Rot)-induced Parkinson disease (PD) in mice as well as their underlying mechanisms.. 56 male C57BL/6 mice were allocated into 8 equal groups, 1) Normal control (CTL), 2) FR (mice received FR at 20 mg/kg/day), 3) Ex (mice received swimming Ex) and 4) Ex + FR (mice received FR and Ex), 5) Rot (mice received Rot 3 mg/Kg i.p. for 70 days), 6) ROT+ FR (mice received Rot + FR at 20 mg/kg/day), 7) ROT+ Ex (mice received Rot + swimming Ex) and 8) ROT+ Ex + FR (mice received Rot + FR and Ex). ROT group showed significant impairment in motor performance and significant reduction in tyrosine hydroxylase (TH) density and Hsp70 expression (p< 0.05) with Lewy bodies (alpha synuclein) aggregates in corpus striatum. Also, ROT+FR, ROT+EX and ROT + Ex+ FR groups showed significant improvement in behavioral and biochemical changes, however the effect of FR alone was more potent than Ex alone (p< 0.05) and addition of Ex to FR caused no more significant improvement than FR alone.. We concluded that, FR and Ex improved the motor performance in rotenone-induced PD rodent model which might be due to increased Hsp70 expression and TH density in corpus striatum and combination of both did not offer more protection than FR alone.

Topics: alpha-Synuclein; Animals; Coumaric Acids; Disease Models, Animal; HSP70 Heat-Shock Proteins; Male; Neuroprotection; Neuroprotective Agents; Parkinson Disease; Physical Conditioning, Animal; Substantia Nigra

Parkinson's disease (PD) is a neurodegenerative disorder characterized by accumulation of misfolded α-synuclein within the central nervous system (CNS). Visual problems in PD patients are common, although retinal pathology associated with PD is not well understood. The purpose of this study was to investigate retinal pathology in a transgenic mouse model (TgM83) expressing the human A53T α-synuclein mutation and assess the effect of α-synuclein "seeding" on the development of retinal pathology. Two-month-old TgM83 mice were intracerebrally inoculated with brain homogenate from old (12-18 months) TgM83 mice. Retinas were then analyzed at 5 months of age. We analyzed retinas from 5-month-old and 8-month-old uninoculated healthy TgM83 mice, and old (12-18 months) mice that were euthanized following the development of clinical signs. Retinas of B6C3H mice (genetic background of the TgM83 mouse) served as control. We used immunohistochemistry and western blot analysis to detect accumulation of α-synuclein, pTau

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Encephalitis; Mice, Transgenic; Neuroglia; Parkinson Disease; Phosphorylation; Retina; tau Proteins

The pathophysiology of Parkinson's disease is characterized by the abnormal accumulation of α-synuclein (α-Syn), eventually resulting in the formation of Lewy bodies and neurites in surviving neurons in the brain. Although α-Syn aggregation has been extensively studied in vitro, there is limited in vivo knowledge on α-Syn aggregation. Here, we used the powerful genetics of Drosophila melanogaster and developed an in vivo assay to monitor α-Syn accumulation by using a bimolecular fluorescence complementation assay. We found that both genetic and pharmacologic manipulations affected α-Syn accumulation. Interestingly, we also found that alterations in the cellular protein degradation mechanisms strongly influenced α-Syn accumulation. Administration of compounds identified as risk factors for Parkinson's disease, such as rotenone or heavy metal ions, had only mild or even no impact on α-Syn accumulation in vivo. Finally, we show that increasing phosphorylation of α-Syn at serine 129 enhances the accumulation and toxicity of α-Syn. Altogether, our study establishes a novel model to study α-Syn accumulation and illustrates the complexity of manipulating proteostasis in vivo.-Prasad, V., Wasser, Y., Hans, F., Goswami, A., Katona, I., Outeiro, T. F., Kahle, P. J., Schulz, J. B., Voigt, A. Monitoring α-synuclein multimerization in vivo.

Topics: alpha-Synuclein; Amyloid; Animals; Disease Models, Animal; Drosophila melanogaster; Male; Phosphorylation; Protein Multimerization; Reactive Oxygen Species; Serine

Protein aggregation in neurons is a prominent pathological mark of neurodegeneration. In Parkinson's disease (PD), inclusions of the α-Synuclein (α-Syn) protein form the Lewy bodies in dopaminergic (DA) neurons. Ectopic expression of human α-Syn inDrosophila neurons leads to the protein accumulation, degeneration of DA neurons and locomotor deterioration, and therefore constitutes the present fly PD model. Yet, this model does not enable to study the role of genes, which are essential for normal development, in neurodegeneration.. Using the Gal80/Gal4/UAS system we optimized the current PD model, such that only the adult stage of the fly is affected by α-Syn expression in the brain.. The symptoms of neurodegeneration typifying the classic model, including reduced locomotor ability, shortened lifespan and the loss of DA neurons, are significantly demonstrated in the novel adult fly PD model.. The neurodegeneration symptoms exhibited by the innovative model are very similar to those manifested in the recognized one.. Specific expression of α-Syn in the adult fly brain enables the investigation of developmental genes involved in neurodegeneration, thereby deciphering gene functions and molecular mechanisms. It may further be used for addressing therapeutic targets and treatment platforms specifically during adult stages.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Behavior, Animal; Brain; Disease Models, Animal; Dopaminergic Neurons; Drosophila melanogaster; Female; Neurons; Parkinson Disease; Protein Aggregation, Pathological

The convergence of human molecular genetics and Lewy pathology of Parkinson's disease (PD) have led to a robust, clinical-stage pipeline of alpha-synuclein (α-syn)-targeted therapies that have the potential to slow or stop the progression of PD and other synucleinopathies. To facilitate the development of these and earlier stage investigational molecules, the Michael J. Fox Foundation for Parkinson's Research convened a group of leaders in the field of PD research from academia and industry, the Alpha-Synuclein Clinical Path Working Group. This group set out to develop recommendations on preclinical and clinical research that can de-risk the development of α-syn targeting therapies. This consensus white paper provides a translational framework, from the selection of animal models and associated end-points to decision-driving biomarkers as well as considerations for the design of clinical proof-of-concept studies. It also identifies current gaps in our biomarker toolkit and the status of the discovery and validation of α-syn-associated biomarkers that could help fill these gaps. Further, it highlights the importance of the emerging digital technology to supplement the capture and monitoring of clinical outcomes. Although the development of disease-modifying therapies targeting α-syn face profound challenges, we remain optimistic that meaningful strides will be made soon toward the identification and approval of disease-modifying therapeutics targeting α-syn.

Topics: alpha-Synuclein; Animals; Biomarkers; Clinical Trials as Topic; Consensus; Disease Models, Animal; Guidelines as Topic; Humans; Parkinson Disease; Proof of Concept Study; Research Design; Translational Research, Biomedical

The activation of microglial cells is presumed to play a key role in the pathogenesis of Parkinson's disease (PD). The activity of microglia is regulated by the histamine-4 receptor (H

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Corpus Striatum; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Histamine; Indoles; Inflammation; Male; Microglia; Nerve Degeneration; Parkinson Disease; Parkinsonian Disorders; Piperazines; Rats; Rats, Sprague-Dawley; Receptors, Histamine H4; Rotenone

Astilbin (AST), a dihydro-flavonol glycoside, is a major bioactive ingredient in Astilbe thunbergii, Engelhardia roxburghiana, Smilax corbularia and Erythroxylum gonocladum, and has been shown to have anti-inflammatory, antioxidative and neuroprotective effects, suggesting potential therapeutic value in the treatment of Parkinson's disease (PD). We explored the neuroprotective effects of AST in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease mice. Mice were administered with MPTP (30 mg/kg, i.p) daily for 5 days, to establish a subacute Parkinson's disease model, followed by daily treatment with AST or saline for 7 days. Pole and traction tests showed that AST ameliorated the impaired motor functions in MPTP-induced Parkinson's disease mice. High performance liquid chromatography analysis revealed that AST treatment prevented MPTP-induced decreases in striatal dopamine levels. Immunofluorescence assays showed that AST reduced the loss of dopaminergic neurons and the activation of microglia and astrocytes in the substantia nigra. Western blot analyses revealed that AST suppressed α-synuclein overexpression and activated PI3K/Akt in the striatum following MPTP treatment. AST also prevented the MPTP-induced reduction in total superoxide dismutase and glutathione activity in the striatum. AST exerts neuroprotective effects on MPTP-induced PD mice by suppressing gliosis, α-synuclein overexpression and oxidative stress, suggesting that AST could serve as a therapeutic drug to ameliorate PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Astrocytes; Disease Models, Animal; Dopaminergic Neurons; Down-Regulation; Flavonols; Humans; Male; Mice; Mice, Inbred C57BL; Microglia; Motor Activity; MPTP Poisoning; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Phosphatidylinositol 3-Kinases; Substantia Nigra

Neuroinflammation and oligodendroglial cytoplasmic α-synuclein (α-syn) inclusions (GCIs) are important neuropathological characteristics of multiple system atrophy (MSA). GCIs are known to interfere with oligodendroglial maturation and consequently result in myelin loss. The neuroinflammatory phenotype in the context of MSA, however, remains poorly understood. Here, we demonstrate MSA-associated neuroinflammation being restricted to myeloid cells and tightly linked to oligodendroglial α-syncleinopathy. In human putaminal post-mortem tissue of MSA patients, neuroinflammation was observed in white matter regions only. This locally restricted neuroinflammation coincided with elevated numbers of α-syn inclusions, while gray matter with less α-synucleinopathy remained unaffected. In order to analyze the temporal pattern of neuroinflammation, a transgenic mouse model overexpressing human α-syn under the control of an oligodendrocyte-specific myelin basic protein (MBP) promoter (MBP29-hα-syn mice) was assessed in a pre-symptomatic and symptomatic disease stage. Strikingly, we detected an increased neuroinflammation in regions with a high α-syn load, the corpus callosum and the striatum, of MBP29-hα-syn mice, already at a pre-symptomatic stage. Furthermore, this inflammatory response was restricted to myeloid cells being highly proliferative and showing an activated, phagocytic phenotype. In contrast, severe astrogliosis was observed only in gray matter regions of MSA patients as well as MBP29-hα-syn mice. To further characterize the influence of oligodendrocytes on initiation of the myeloid immune response, we performed RNA sequencing analysis of α-syn overexpressing primary oligodendrocytes. A distinct gene expression profile including upregulation of cytokines important for myeloid cell attraction and proliferation was detected in α-syn overexpressing oligodendrocytes. Additionally, microdissected tissue of MBP29-hα-syn mice exhibited a similar cellular gene expression profile in white matter regions even pre-symptomatically. Collectively, these results imply an early crosstalk between neuroinflammation and oligodendrocytes containing α-syn inclusions leading to an immune response locally restricted to white matter regions in MSA.

Topics: Aged; alpha-Synuclein; Animals; Brain; Corpus Striatum; Disease Models, Animal; Female; Humans; Inclusion Bodies; Male; Mice; Mice, Transgenic; Middle Aged; Multiple System Atrophy; Myeloid Cells; Neuroimmunomodulation; Neurons; Oligodendroglia; Synucleinopathies; White Matter

MSA is a fatal neurodegenerative disease characterized by autonomic failure and severe motor impairment. Its main pathological hallmark is the accumulation of α-synuclein in oligodendrocytes, leading to glial and neuronal dysfunction and neurodegeneration. These features are recapitulated in the PLP-hαSyn mouse model expressing human α-synuclein in oligodendrocytes. At present, there is no effective disease-modifying therapy. Previous experiments have shown that the aggregation inhibitor, anle138b, reduces neurodegeneration and behavioral deficits in mouse models of other proteinopathies.. To test the therapeutic potential of anle138b in a mouse model of MSA.. Two-month-old PLP-hαSyn mice were fed over a period of 4 months with pellets containing anle138b at two different doses (0.6 and 2 g/kg) and compared to healthy controls and PLP-hαSyn mice fed with placebo pellets. At the end of the treatment, behavioral and histological analyses were performed.. We observed a reversal of motor function to healthy control levels when PLP-hαSyn mice were treated with both doses of anle138b. Histological and molecular analyses showed a significant reduction in α-synuclein oligomers and glial cytoplasmic inclusions in animals fed with anle138b compared to nontreated mice. These animals also present preservation of dopaminergic neurons and reduction in microglial activation in SN correlating with the α-synuclein reduction observed.. Anle138b reduces α-synuclein accumulation in PLP-hαSyn mice, leading to neuroprotection, reduction of microglial activation, and preservation of motor function supporting the use of anle138b in a future clinical trial for MSA. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Benzodioxoles; Disease Models, Animal; Mice, Transgenic; Movement Disorders; Multiple System Atrophy; Nerve Degeneration; Neuroglia; Neurons; Oligodendroglia; Pyrazoles

It has been suggested that aggregation of α-synuclein (α-syn) into oligomers leads to neurodegeneration in Parkinson's disease (PD), but intravenous immunoglobulin (IVIG) which contains antibodies against α-syn monomers and oligomers fails to treat PD mouse model. The reason may be because IVIG contains much low level of antibodies against α-syn, and of which only a small part can penetrate the blood-brain barrier, resulting in an extremely low level of effective antibodies in the brain, and limiting the beneficial effect of IVIG on PD mice. Here, we first isolated naturally occurring autoantibodies against α-syn (NAbs-α-syn) from IVIG. Our further investigation results showed that NAbs-α-syn inhibited α-syn aggregation and attenuated α-syn-induced cytotoxicity in vitro. Compared with vehicles, NAbs-α-syn significantly attenuated the memory and motor deficits by reducing the levels of soluble α-syn, total human α-syn and α-syn oligomers, decreasing the intracellular p-α-syn

Topics: alpha-Synuclein; Animals; Autoantibodies; Brain; Disease Models, Animal; Immunization, Passive; Immunoglobulins, Intravenous; Mice, Transgenic; Microglia; Motor Activity; Parkinson Disease; Protein Aggregation, Pathological; Spatial Memory

In Parkinson's disease (PD), α-synuclein (αS) pathologically impacts the brain, a highly lipid-rich organ. We investigated how alterations in αS or lipid/fatty acid homeostasis affect each other. Lipidomic profiling of human αS-expressing yeast revealed increases in oleic acid (OA, 18:1), diglycerides, and triglycerides. These findings were recapitulated in rodent and human neuronal models of αS dyshomeostasis (overexpression; patient-derived triplication or E46K mutation; E46K mice). Preventing lipid droplet formation or augmenting OA increased αS yeast toxicity; suppressing the OA-generating enzyme stearoyl-CoA-desaturase (SCD) was protective. Genetic or pharmacological SCD inhibition ameliorated toxicity in αS-overexpressing rat neurons. In a C. elegans model, SCD knockout prevented αS-induced dopaminergic degeneration. Conversely, we observed detrimental effects of OA on αS homeostasis: in human neural cells, excess OA caused αS inclusion formation, which was reversed by SCD inhibition. Thus, monounsaturated fatty acid metabolism is pivotal for αS-induced neurotoxicity, and inhibiting SCD represents a novel PD therapeutic approach.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Caenorhabditis elegans; Cell Line; Cerebral Cortex; Diglycerides; Disease Models, Animal; Dopaminergic Neurons; Drug Discovery; Enzyme Inhibitors; Humans; Induced Pluripotent Stem Cells; Lipid Droplets; Lipid Metabolism; Metabolomics; Mice, Inbred C57BL; Mice, Transgenic; Molecular Targeted Therapy; Nerve Degeneration; Neural Stem Cells; Neurons; Oleic Acid; Parkinson Disease; Rats, Sprague-Dawley; Saccharomyces cerevisiae; Stearoyl-CoA Desaturase; Triglycerides

Piper nigrum L. and Piper longum L. consist a classic formula in traditional Chinese Hui medicine and are widely used in treatment of stroke. To examine the therapeutic effect of neuron injury after apoplexy, we used a permanent middle cerebral artery occlusion model in rats to investigate the effects of dichloromethane fraction (DF) of Piper nigrum L. and Piper longum L.. DF alleviated neurological deficits and markedly prevented ischemia-induced cellular damage. Immunohistochemical micrographs revealed that PSD-95 and syn-I proteins increased, and α-syn presented reduced expression in brain samples from the sham group. Western blot analyses revealed that the model group exhibited a noticeable reduction in PSD-95, p-CaMK II, CaM, and NR2B. The DF-treated model group exhibited increased PSD-95, p-CaMK II, CaM, and NR2B. UPLC-Q-TOF/MS analysis revealed eight main components of DF, of which piperine accounted for the largest proportion.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calmodulin; Disease Models, Animal; Disks Large Homolog 4 Protein; Infarction, Middle Cerebral Artery; Male; Methylene Chloride; Motor Activity; Neurons; Neuroprotective Agents; Phosphorylation; Piper; Piper nigrum; Plant Extracts; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Solvents; Synapsins

The intestinal microbiota actively converts dietary flavanols into phenolic acids, some of which are bioavailable in vivo and may promote resilience to select neurological disorders by interfering with key pathologic mechanisms. Since every person harbors a unique set of gut bacteria, we investigated the influence of the gut microbiota's interpersonal heterogeneity on the production and bioavailability of flavonoid metabolites that may interfere with the misfolding of alpha (α)-synuclein, a process that plays a central role in Parkinson's disease and other α-synucleinopathies. We generated two experimental groups of humanized gnotobiotic mice with compositionally diverse gut bacteria and orally treated the mice with a flavanol-rich preparation (FRP). The two gnotobiotic mouse groups exhibited distinct differences in the generation and bioavailability of FRP-derived microbial phenolic acid metabolites that have bioactivity towards interfering with α-synuclein misfolding or inflammation. We also demonstrated that these bioactive phenolic acids are effective in modulating the development and progression of motor dysfunction in a Drosophila model of α-synucleinopathy. Lastly, through in vitro bacterial fermentation studies, we identified select bacteria that are capable of supporting the generation of these bioavailable and bioactive phenolic acids. Outcomes from our studies provide a better understanding of how interpersonal heterogeneity in the gut microbiota differentially modulates the efficacy of dietary flavanols to protect against select pathologic mechanisms. Collectively, our findings provide the basis for future developments of probiotic, prebiotic, or synbiotic approaches for modulating the onset and/or progression of α-synucleinopathies and other neurological disorders involving protein misfolding and/or inflammation.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Biological Availability; Brain; Disease Models, Animal; Drosophila; Female; Gastrointestinal Microbiome; Humans; Male; Mice, Inbred C57BL; Parkinson Disease; Polyphenols; Protein Aggregation, Pathological; Protein Folding; Specific Pathogen-Free Organisms; Synucleinopathies

Parkinson's disease (PD) is a progressive, disabling neurodegenerative disorder. It has been shown Toll like receptor (TLR) 4-deficient mice protect against MPTP toxicity, suggesting that dopaminergic cell death is TLR4-dependent. The aim of this study was to demonstrate, in an in vivo model of PD, how TLR4 plays its important role in the pathogenesis of PD by using MPTP neurotoxin model (4 × 20 mg/kg, 2 h apart, i.p). Our experiments have demonstrated that the absence of TLR4 prevented dopamine depletion, increased tyrosine hydroxylase and dopamine transporter activities and reduced the number of α-synuclein-positive neurons. The absence of TLR4 also had an impact on inflammatory processes, modulating the transcription factors NF-κB p65 and AP-1, and reducing astrogliosis. Importantly, we demonstrated that the absence of TLR4 modulated inflammosome pathway. Moreover, it has been shown that TLR4 modulated motor and non-motor symptoms typical of PD. Our results clearly demonstrated that absence of TLR4 reduces the development of neuroinflammation associated with PD through NF-κB, AP-1 and inflammasome pathways modulation; therefore, TLR4 could be considered as an encouraging therapeutic target in neurodegenerative disorders.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Cytokines; Disease Models, Animal; Dopaminergic Neurons; Inflammasomes; Inflammation; Male; Mice; Mice, Inbred C57BL; Microglia; Neuroimmunomodulation; Neuroprotective Agents; NF-kappa B; Parkinson Disease; Signal Transduction; Toll-Like Receptor 4; Transcription Factor AP-1; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a well-known neurodegenerative disorder characterized by dopaminergic (DA) neuron loss and α-synuclein aggregation. Recent study revealed that the extracts from sea cucumber, Holothuroidea spp., exhibited neuroprotective and lifespan extension effects in Caenorhabditis elegans model. Interestingly, the black sea cucumber, Holothuria leucospilota, possesses body wall and a specialized organ called cuvierian tubules containing high amount of bioactive compounds. In this study, the neuroprotective effects of the body wall (BW) and cuvierian tubules (CT) from this sea cucumber against PD were evaluated using C. elegans as a model. H. leucospilota were extracted using ethanol (ET), ethyl acetate (EA), butanol (BU) and aqueous (AQ) fractions. Extracts from these fractions were used to treat the 6-OHDA-induced BZ555 and α-synuclein expressing NL5901 strains of C. elegans. Treatment with ET, EA, BU and AQ fractions of H. leucospilota extracts could significantly prevent degeneration of DA neurons in 6-OHDA-induced worms, improve food-sensing behavior mediated by DA neurons, and up-regulate cat-2 and sod-3 gene expressions. These results indicate the neuroprotective activity of the extracts which may be attributed to the anti-oxidant activity of the bioactive compounds. Moreover, α-synuclein aggregation was significantly reduced together with the recovery of lipid deposition upon the treatment with H. leucospilota extracts. In addition, treatment with H. leucospilota extracts was able to increase the lifespan of 6-OHDA-induced N2. NMR analysis revealed the major chemical components in the effective EA fractions were terpenoids, steroids, saponins, and glycosides. In summary, H. leucospilota extracts exhibited anti-Parkinson effect in both toxin-induced and transgenic C. elegans models of PD. Further study will be performed to elucidate the most effective anti-PD molecules which will lead to the development of anti-PD drug.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Holothuria; Nerve Degeneration; Neuroprotective Agents; Parkinson Disease

Drug discovery for Parkinson's disease (PD) is challenging. Here we report that gold nanoclusters (AuNCs) can serve as a novel candidate for the design of anti-PD drugs. With N-isobutyryl-l-cysteine (L-NIBC) protected AuNCs as an example, we show that AuNCs effectively prevent α-Synuclein (α-Syn) fibrillation in in vitro experiments. Cell experiments demonstrate good neuroprotective effects in PD cell models. More significantly, experiments of mouse PD model further show that AuNCs largely ameliorate the behavioral disorders of sick mice. In addition, immunohistochemical and western blot (WB) analyses indicate that AuNCs can significantly reverse dopaminergic (DA) neuron loss in substantia nigra and striatum of sick mice. This study opens up a novel avenue to develop anti-PD drugs and points a new direction for AuNCs in medicinal applications.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Cysteine; Disease Models, Animal; Gold; Male; Mice, Inbred C57BL; Nanoparticles; Parkinson Disease; PC12 Cells; Rats

Gait and postural control dysfunction are prototypical symptoms compromising quality of life for patients with Parkinson's disease (PD). Hallmarks of cellular pathology are dopaminergic degeneration and accumulation of the cytosolic protein alpha-synuclein, linked to impaired autophagy-lysosome pathway (ALP) clearance. Physical exercise improves gait in PD patients and motor function in rodent lesion models. Moreover, exercise is considered neuroprotective and ALP induction has been reported, e.g. in human skeletal muscle, rodent peripheral and cerebral tissues. A combined analysis of how distinct exercise paradigms affect motor and central biochemical aspects of PD could maximize benefits for patients. Here we examine the effect of 4 weeks treadmill exercise intervention in 7-8 month non-lesioned mice on a) distinct gait categories, b) ALP activity, c) dopaminergic and alpha-synuclein homeostasis. The study includes wild type, alpha-synuclein knockout, and mice exclusively expressing human alpha-synuclein. Parameters of gait regularity and stability, activity, and dynamic postural control during unforced walk, were assessed by an automated system (CatWalk XT). At baseline, alpha-synuclein mouse models exhibited irregular and less active gait, with impaired dynamic postural control, compared to wild type mice. Treadmill exercise particularly improved speed and stride length, while increasing dual diagonal versus three-paw body support in both the alpha-synuclein knockout and transgenic mice. Biochemical analyses showed higher striatal tyrosine hydroxylase immuno-reactivity and reduced higher-order alpha-synuclein species in the cerebral cortex. However, no significant cerebral ALP induction was measured. In summary, treadmill exercise improved gait activity and postural stability, and promoted dopaminergic and alpha-synuclein homeostasis, without robustly inducing cerebral ALP.

Topics: alpha-Synuclein; Animals; Autophagy; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Exercise Therapy; Gait; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Neuroprotection; Parkinson Disease; Physical Conditioning, Animal; Physical Exertion; Posture; Substantia Nigra

Gaucher disease (GD) patients and carriers of GD mutations have a higher propensity to develop Parkinson's disease (PD) in comparison to the non-GD population. This implies that mutant GBA1 allele is a predisposing factor for the development of PD. One of the major characteristics of PD is the presence of oligomeric α-synuclein-positive inclusions known as Lewy bodies in the dopaminergic neurons localized to the substantia nigra pars compacta. In the present study we tested whether presence of human mutant GCase leads to accumulation and aggregation of α-synuclein in two models: in SHSY5Y neuroblastoma cells endogenously expressing α-synuclein and stably transfected with human GCase variants, and in Drosophila melanogaster co-expressing normal human α-synuclein and mutant human GCase. Our results showed that heterologous expression of mutant, but not WT, human GCase in SHSY5Y cells, led to a significant stabilization of α-synuclein and to its aggregation. In parallel, there was also a significant stabilization of mutant, but not WT, GCase. Co-expression of human α-synuclein and human mutant GCase in the dopaminergic cells of flies initiated α-synuclein aggregation, earlier death of these cells and significantly shorter life span, compared with flies expressing α-synuclein or mutant GCase alone. Taken together, our results strongly indicate that human mutant GCase contributes to accumulation and aggregation of α-synuclein. In the fly, this aggregation leads to development of more severe parkinsonian signs in comparison to flies expressing either mutant GCase or α-synuclein alone.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Dopaminergic Neurons; Drosophila melanogaster; Gaucher Disease; Gene Expression Regulation; Glucosylceramidase; Heterozygote; Humans; Lewy Bodies; Lysosomes; Mutation; Parkinson Disease; Pars Compacta; Protein Aggregation, Pathological

Parkinson's disease (PD) is characterized by motor deficits, although cognitive disturbances are frequent and have been noted early in the disease. The main pathological characteristics of PD are the loss of dopaminergic neurons and the presence of aggregated α-synuclein in Lewy bodies of surviving cells. Studies have also documented the presence of other proteins within Lewy bodies, particularly tau, a microtubule-associated protein implicated in a wide range of neurodegenerative diseases, including Alzheimer's disease (AD). In AD, tau pathology correlates with cognitive dysfunction, and tau mutations have been reported to lead to dementia associated with parkinsonism. However, the role of tau in PD pathogenesis remains unclear. To address this question, we induced parkinsonism by injecting the toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in hTau mice, a mouse model of tauopathy expressing human tau, and a mouse model knock-out for tau (TKO). We found that although MPTP impaired locomotion (gait analysis) and cognition (Barnes maze), there were no discernable differences between hTau and TKO mice. MPTP also induced a slight but significant increase in tau phosphorylation (Thr205) in the hippocampus of hTau mice, as well as a significant decrease in the soluble and insoluble tau fractions that correlated with the loss of dopaminergic neurons in the brainstem. Overall, our findings suggest that, although MPTP can induce an increase in tau phosphorylation at specific epitopes, tau does not seem to causally contribute to cognitive and locomotor deficits induced by this toxin.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Alzheimer Disease; Animals; Brain; Cognition; Disease Models, Animal; Dopaminergic Neurons; Female; Hippocampus; Humans; Locomotion; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Parkinson Disease; Phosphorylation; tau Proteins; Tauopathies

Parkinson's disease (PD) features the degeneration and death of dopamine neurons in the substantia nigra pars compacta and the formation of Lewy bodies that contain α-synuclein. Among the numerous PD etiologies, glutamate excitotoxicity is a research hot spot, and glutamate transporters play key roles in this theory. It has been shown that the expression of the glutamate transporter is regulated by microRNAs. In this study, we found that the levels of expression and function of glutamate transporter type 1 (GLT-1) were significantly reduced and miR-543-3p was upregulated during the development of PD. Furthermore, our results indicated that GLT-1 plays an important role in the pathomechanism of PD. We found that miR-543-3p can suppress the expression and function of GLT-1 in MPP

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Disease Models, Animal; Dopaminergic Neurons; Lewy Bodies; Mice; MicroRNAs; Parkinson Disease; Pars Compacta; Substantia Nigra

Parkinson's disease (PD) is characterized by dopaminergic (DA) cell loss and the accumulation of pathological alpha synuclein (asyn), but its precise pathomechanism remains unclear, and no appropriate animal model has yet been established. Recent studies have shown that a heterozygous mutation of glucocerebrosidase (gba) is one of the most important genetic risk factors in PD. To create mouse model for PD, we crossed asyn Bacterial Artificial Chromosome transgenic mice with gba heterozygous knockout mice. These double-mutant (dm) mice express human asyn in a physiological manner through its native promoter and showed an increase in phosphorylated asyn in the regions vulnerable to PD, such as the olfactory bulb and dorsal motor nucleus of the vagus nerve. Only dm mice showed a significant reduction in DA cells in the substantia nigra pars compacta, suggesting these animals were suitable for a prodromal model of PD. Next, we investigated the in vivo mechanism by which GBA insufficiency accelerates PD pathology, focusing on lipid metabolism. Dm mice showed an increased level of glucosylsphingosine without any noticeable accumulation of glucosylceramide, a direct substrate of GBA. In addition, the overexpression of asyn resulted in decreased GBA activity in mice, while dm mice tended to show an even further decreased level of GBA activity. In conclusion, we created a novel prodromal mouse model to study the disease pathogenesis and develop novel therapeutics for PD and also revealed the mechanism by which heterozygous gba deficiency contributes to PD through abnormal lipid metabolism under conditions of an altered asyn expression in vivo.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Glucosylceramidase; Humans; Lipid Metabolism; Mice; Mice, Knockout; Mice, Transgenic; Parkinson Disease; Pars Compacta; Prodromal Symptoms

Progressive accumulation of α-synuclein (α-syn) and exposure to environmental toxins are risk factors that may both concur to Parkinson's disease (PD) pathogenesis. Electrophysiological recordings of field postsynaptic potentials (fEPSPs) and Ca

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Humans; Mitochondria; Neurons; Parkinson Disease; Rats; Rats, Wistar; Rotenone; Sodium-Calcium Exchanger

Topics: alpha-Synuclein; Animals; Biomarkers; Cell Death; Disease Models, Animal; Humans; Mice; Nitric Oxide; Parkinson Disease; Poly (ADP-Ribose) Polymerase-1; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerase Inhibitors

Treatment with the dopamine (DA) precursor l-3,4-dihydroxyphenylalanine (l-DOPA) provides symptomatic relief arising from DA denervation in Parkinson's disease. Mounting evidence that DA autooxidation to neurotoxic quinones is involved in Parkinson's disease pathogenesis has raised concern about potentiation of oxidative stress by l-DOPA. The rate of DA quinone formation increases in the presence of excess redox-active iron (Fe), which is a pathological hallmark of Parkinson's disease. Conversely, l-DOPA has pH-dependent Fe-chelating properties, and may act to 'redox silence' Fe and partially allay DA autoxidation. We examined the effects of l-DOPA in three murine models of parkinsonian neurodegeneration: early-life Fe overexposure in wild-type mice, transgenic human (h)A53T mutant α-synuclein (α-syn) over-expression, and a combined 'multi-hit' model of Fe-overload in hA53T mice. We found that l-DOPA was neuroprotective and prevented age-related Fe accumulation in the substantia nigra pars compacta (SNc), similar to the mild-affinity Fe chelator clioquinol. Chronic l-DOPA treatment showed no evidence of increased oxidative stress in wild-type midbrain and normalized motor performance, when excess Fe was present. Similarly, l-DOPA also did not exacerbate protein oxidation levels in hA53T mice, with or without excess nigral Fe, and showed evidence of neuroprotection. The effects of l-DOPA in Fe-fed hA53T mice were somewhat muted, suggesting that Fe-chelation alone is insufficient to attenuate neuron loss in an animal model also recapitulating altered DA metabolism. In summary, we found no evidence in any of our model systems that l-DOPA treatment accentuated neurodegeneration, suggesting DA replacement therapy does not contribute to oxidative stress in the Parkinson's disease brain.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Brain; Disease Models, Animal; Dopaminergic Neurons; Humans; Iron; Iron Overload; Levodopa; Mice; Mice, Transgenic; Nerve Degeneration; Oxidative Stress; Parkinson Disease

The neuropathology of Parkinson's disease with dementia (PDD) has been reported to involve heterogeneous and various disease mechanisms. Alpha-synuclein (α-syn) and amyloid beta (Aβ) pathology are associated with the cognitive status of PDD, and NADPH oxidase (NOX) is known to affect a variety of cognitive functions. We investigated the effects of NOX on cognitive impairment and on α-syn and Aβ expression and aggregation in PDD. In the 6-hydroxydopamine (6-OHDA)-injected mouse model, cognitive and motor function, and the levels of α-syn, Aβ, and oligomer A11 after inhibition of NOX4 expression in the hippocampal dentate gyrus (DG) were measured by the Morris water maze, novel object recognition, rotation, and rotarod tests, as well as immunoblotting and immunohistochemistry. After 6-OHDA administration, the death of nigrostriatal dopamine neurons and the expression of α-syn and NOX1 in the substantia nigra were increased, and phosphorylated α-syn, Aβ, oligomer A11, and NOX4 were upregulated in the hippocampus. 6-OHDA dose-dependent cognitive impairment was observed, and the increased cognitive impairment, Aβ expression, and oligomer A11 production in 6-OHDA-treated mice were suppressed by NOX4 knockdown in the hippocampal DG. Our results suggest that increased expression of NOX4 in the hippocampal DG in the 6-OHDA-treated mouse induces Aβ expression and oligomer A11 production, thereby reducing cognitive function.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Animals; Biomarkers; Corpus Striatum; Dementia; Disease Models, Animal; Gene Knockdown Techniques; Hippocampus; Humans; Male; Mice; Middle Aged; NADPH Oxidase 4; Neurons; Parkinson Disease; Phosphorylation; Substantia Nigra

Parkinson's disease (PD) is a progressive neurological motor control disorder. A key feature is the loss of midbrain dopaminergic neurons and the accumulation of aggregated alpha-synuclein (α-syn). No current treatment is on the market that slows or halts disease progression. Previous studies have shown that glucagon-like peptide-1 (GLP-1) receptor agonists have neuroprotective effects in animal models of PD. In addition, in a phase II clinical trial, the GLP-1 receptor agonist exendin-4 has shown good protective effects in PD patients. In the present study, we have investigated the neuroprotective effects of the GLP-1 analogues semaglutide (25 nmol/kg ip. once every two days for 30 days) and liraglutide (25 nmol/kg ip. once daily for 30 days) in the chronic MPTP mouse model of PD. Both drugs are currently on the market as a treatment for Type II diabetes. Our results show that both semaglutide and liraglutide improved MPTP-induced motor impairments. In addition, both drugs rescued the decrease of tyrosine hydroxylase (TH) levels, reduced the accumulation of α-syn, alleviated the chronic inflammation response in the brain, reduced lipid peroxidation, and inhibited the mitochondrial mitophagy signaling pathway, and furthermore increased expression of the key growth factor GDNF that protects dopaminergic neurons in the substantia nigra (SN) and striatum. Moreover, the long- acting GLP-1 analogue semaglutide was more potent compared with once daily liraglutide in most parameters measured in this study. Our results demonstrate that semaglutide may be a promising treatment for PD. A clinical trial testing semaglutide in PD patients will start shortly.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Glucagon-Like Peptides; Hypoglycemic Agents; Liraglutide; Mice; MPTP Poisoning; Neuroprotective Agents; Oxidative Stress

Parkinson's disease (PD) is a neurodegenerative disease characterized by α-synuclein-positive inclusion bodies and loss of neurons, including dopaminergic neurons. Difficulty in replicating PD phenotypes using animal models partly limits the understanding of PD and the therapy required. Although PD is strongly associated with aging, most experimental animals may not exhibit age-related symptoms. Herein, we demonstrate that Nothobranchius furzeri, a rapidly aging teleost with a short life span, exhibits age-dependent degeneration of dopaminergic and noradrenergic neurons and progression of α-synuclein pathologies. These pathological phenotypes are similar to those observed in human patients with PD. Amelioration of the cell loss by genetic depletion of α-synuclein suggests that α-synuclein is not a bystander but a causative protein of neurodegeneration. N. furzeri can reveal mechanisms underlying PD, especially of the idiopathic form that affects a majority of patients with PD, including α-synuclein-dependent neurodegeneration, age-dependent phenotypes, and progression of α-synuclein pathology.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Fishes; Fundulidae; Humans; Neurons; Parkinson Disease

Innate immune activation and chronic neuroinflammation are characteristic features of many neurodegenerative diseases including Parkinson's disease (PD) and may contribute to the pathophysiology of the disease. The discovery of misfolded alpha-synuclein (αSYN) protein aggregates, which amplify in a "prion-like" fashion, has led us to consider that pathogenic αSYN might be hijacking the activation and mobilization mechanism of the peripheral immune system to reach and disseminate within the CNS. Furthermore, our lab and other groups have recently shown that αSYN can adopt distinct fibril conformations or "strains" with varying levels of pathogenic impact. Therefore, the aim of this study was to assess the impact of peripheral inflammation on αSYN spreading in order to better understand the participation of the immune system in the progression of PD. The results presented here show that intraperitoneal LPS injection prior to systemic intravenous recombinant administration of two different αSYN pathogenic strains (fibrils or ribbons) in wild type mice, induces an increase in brain resident microglia and promotes the recruitment of leukocytes toward the brain and the spinal cord. Our findings show for the first time that αSYN can be internalized by LPS-primed inflammatory monocytes, which in turn favors the dissemination from the periphery toward the brain and spinal cord. Further, we found a differential recruitment of CD4

Topics: Administration, Intravenous; alpha-Synuclein; Animals; Brain; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Disease Models, Animal; Female; Immunologic Surveillance; Inflammation; Injections, Intraperitoneal; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Microglia; Monocytes; Parkinson Disease; Protein Aggregates; Spinal Cord

Caenorhabditis elegans is widely used to investigate biological processes related to health and disease. Multiple C. elegans models for human neurodegenerative diseases do exist, including those expressing human α-synuclein. Even though these models do not feature all pathological and molecular hallmarks of the disease they mimic, they allow for the identification and dissection of molecular pathways that are involved. In line with this, genetic screens have yielded multiple modifiers of proteotoxicity in C. elegans models for neurodegenerative diseases. Here, we describe a set of common screening approaches and tools that can be used to study synucleinopathies and other neurodegenerative diseases in C. elegans. RNA interference and mutagenesis screens can be used to find genes that affect proteotoxicity, while relatively simple molecular, cellular (fractionation studies), metabolic (respiration studies), and behavioral (thrashing and crawling) readouts can be used to study the effects of disease proteins and modifiers more closely.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Cell Nucleus; Cytosol; Disease Models, Animal; Humans; Neurodegenerative Diseases; Protein Folding; Protein Transport; RNA Interference

Parkinson's disease is the second most common neurodegenerative disease without cure. It is characterized by α-synuclein accumulation and aggregation in dopaminergic and other types of neurons. Because α-synuclein accumulation leads to a toxic gain of function, its ectopic expression in Drosophila has been a useful in vivo model for testing modifiers of its toxicity. This chapter describes four assays: the rapid iterative negative geotaxis, rough eye phenotype, quantification of dopaminergic neuronal loss, and measurements of circadian effects.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Behavior, Animal; Biological Assay; Biomarkers; Circadian Rhythm; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Locomotion; Parkinson Disease

Cardiolipin (CL) is a mitochondrial signature phospholipid that is required for membrane structure, respiration, dynamics, and mitophagy. Oxidative damage of CL by reactive oxygen species is implicated in the pathogenesis of Parkinson's disease (PD), but the underlying cause remains elusive. This work investigated the role of ALCAT1, an acyltransferase that catalyzes pathological remodeling of CL in various aging-related diseases, in a mouse model of PD induced by 1-methyl-4-phenyl-1,2,4,6-tetrahydropyridine (MPTP). We show that MPTP treatment caused oxidative stress, mtDNA mutations, and mitochondrial dysfunction in the midbrain. In contrast, ablation of the ALCAT1 gene or pharmacological inhibition of ALCAT1 prevented MPTP-induced neurotoxicity, apoptosis, and motor deficits. ALCAT1 deficiency also mitigated mitochondrial dysfunction by modulating DRP1 translocation to the mitochondria. Moreover, pharmacological inhibition of ALCAT1 significantly improved mitophagy by promoting the recruitment of Parkin to dysfunctional mitochondria. Finally, ALCAT1 expression was upregulated by MPTP and by α-synucleinopathy, a key hallmark of PD, whereas ALCAT1 deficiency prevented α-synuclein oligomerization and S-129 phosphorylation, implicating a key role of ALCAT1 in the etiology of mouse models of PD. Together, these findings identify ALCAT1 as a novel drug target for the treatment of PD.

Topics: Acyltransferases; alpha-Synuclein; Animals; Apoptosis; Cardiolipins; Cell Line, Tumor; Disease Models, Animal; Humans; Locomotion; Mice; Mice, Transgenic; Mitochondria; Mitochondrial Dynamics; Mitophagy; MPTP Poisoning; Nerve Degeneration; Phosphorylation; Reactive Oxygen Species; Ubiquitin-Protein Ligases

Mutations in the

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Gene Knock-In Techniques; Male; Mice; Mutation; Nervous System Diseases; Neurodegenerative Diseases; Neuropathology; Parkinson Disease; Protein Transport; tau Proteins; Vesicular Transport Proteins

In Parkinson's disease (PD) there is a selective degeneration of neuromelanin-containing neurons, especially substantia nigra dopaminergic neurons. In humans, neuromelanin accumulates with age, the latter being the main risk factor for PD. The contribution of neuromelanin to PD pathogenesis remains unknown because, unlike humans, common laboratory animals lack neuromelanin. Synthesis of peripheral melanins is mediated by tyrosinase, an enzyme also present at low levels in the brain. Here we report that overexpression of human tyrosinase in rat substantia nigra results in age-dependent production of human-like neuromelanin within nigral dopaminergic neurons, up to levels reached in elderly humans. In these animals, intracellular neuromelanin accumulation above a specific threshold is associated to an age-dependent PD phenotype, including hypokinesia, Lewy body-like formation and nigrostriatal neurodegeneration. Enhancing lysosomal proteostasis reduces intracellular neuromelanin and prevents neurodegeneration in tyrosinase-overexpressing animals. Our results suggest that intracellular neuromelanin levels may set the threshold for the initiation of PD.

Topics: Aging; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopaminergic Neurons; Humans; Lewy Bodies; Male; Melanins; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Monophenol Monooxygenase; Parkinson Disease; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Recombinant Proteins; Substantia Nigra

α-Synuclein (α-syn) is a small presynaptic protein distributed ubiquitously in the central and peripheral nervous system. In normal conditions, α-syn is found in soluble form, while in Parkinson's disease (PD) it may phosphorylate, aggregate, and combine with other proteins to form Lewy bodies. The purpose of this study was to evaluate, in nonhuman primates, whether α-syn expression is affected by age and neurotoxin challenge. Young adult (

Topics: Adult; alpha-Synuclein; Animals; Child; Child, Preschool; Disease Models, Animal; GABAergic Neurons; Humans; Macaca mulatta; Male; Parkinsonian Disorders; Substantia Nigra; Young Adult

The aggregation of α-synuclein (αSyn) is considered a key pathophysiological feature of certain neurodegenerative disorders, collectively termed synucleinopathies. Given that a prion-like, cell-to-cell transfer of misfolded αSyn has been recognized in the spreading of αSyn pathology in synucleinopathies, we investigated the biological mechanisms underlying the propagation of the disease with respect to environmental neurotoxic stress. Considering the potential role of the divalent metal manganese (Mn

Topics: alpha-Synuclein; Animals; Cell Line; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Exosomes; Manganese; Mice; Parkinson Disease, Secondary; Prions; Protein Aggregation, Pathological

Dopamine (DA) release in striatum is functionally segregated across a dorsolateral/ventromedial axis. Interestingly, nigrostriatal DA signaling disruption in Parkinson's disease (PD) preferentially affects the dorsolateral striatum. The relationship between afferent presynaptic calcium transients (PreCaTs) in DA terminals and DA release in dorsolateral (Caudato-Putamen, DLS) and ventromedial (Nucleus Accumbens Shell, VS) striatal subregions was examined by ex vivo real-time dual-recording in conditional transgenic mice expressing the calcium indicator protein GCaMP3. In DLS, minimal increases in cytosolic calcium trigger steep DA release while PreCaTs and DA release in VS both were proportional to the number of pulses in burst stimulation. Co-expressing α-synuclein with the Parkinson's disease (PD)-associated A53T mutation and GCaMP3 in midbrain DA neurons revealed augmented cytosolic steady state and activity-dependent intra-terminal calcium levels preferentially in DLS, as well as hyperactivation and enhanced expression of N-type calcium channels. Thus, unbalanced calcium channel activity is a presynaptic mechanism to consider in the multifaceted pathogenic pathways of progressive neurodegeneration.

Topics: alpha-Synuclein; Animals; Calcium; Calcium Channels; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Mice; Mice, Transgenic; Neostriatum; Parkinson Disease; Signal Transduction; Substantia Nigra

Sanfilippo syndrome (mucopolysaccharidosis type IIIA; MPS IIIA) is an inherited paediatric-onset neurodegenerative disorder caused by the lysosomal deficiency of sulphamidase with subsequent accumulation of heparan sulphate. The pathological mechanisms responsible for clinical disease are unknown; however, intraneuronal accumulation of aggregation-prone proteins such as α-synuclein, phosphorylated tau and amyloid precursor protein suggests inefficient intracellular trafficking and lysosomal degradation.. To investigate the contribution the accumulating α-synuclein plays in early symptom emergence that is, impaired cognition, reduced anxiety and motor deficits, first detectable between 3-5 months of age.. In a battery of behavioural tests performed on mice aged 12-22 weeks, we were unable to differentiate α-synuclein-deficient MPS IIIA mice from those with one or both copies of the α-synuclein gene; all three affected genotypes were significantly impaired in test performance when compared to wild-type littermates. Histological studies revealed that the rate, location and nature of deposition of other proteinaceous lesions, the disruption to endolysosomal protein expression and the inflammatory response seen in the brain of α-synuclein-deficient MPS IIIA mice reflected that seen in MPS IIIA mice homo- or heterozygous for α-synuclein.. Deletion and/or deficiency of α-synuclein does not influence clinical and neuropathological disease progression in murine MPS IIIA, demonstrating that in and of itself, this protein does not initiate the cognitive and motor symptoms that occur in the first 5 months of life in MPS IIIA mice.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Disease Progression; Mice; Mice, Knockout; Mucopolysaccharidosis III

There is a critical need to include female subjects in disease research; however, in Parkinson's disease, where the male-to-female incidence is about 1.5-to-1, the majority of preclinical research is conducted in male animals. The mitochondrial complex I inhibitor, rotenone, is selectively toxic to dopaminergic neurons, and reproduces several neuropathological features of Parkinson's disease, including α-synuclein pathology. Rotenone has been primarily utilized in male Lewis rats; however, pilot studies in age-matched female Lewis rats revealed that our usual dose (2.8 mg/kg/day intraperitoneal [i.p.]) did not cause dopaminergic neurodegeneration. Therefore, we compared rotenone-treated males (2.8 mg/kg/day, i.p.) to females at increasing doses (2.8 mg/kg/day, 3.2 mg/kg/day, 3.6 mg/kg/day, and 1.6 mg/kg bis in die, i.p.). Female rats receiving 3.2 mg/kg, and 3.6 mg/kg rotenone displayed significant loss of dopaminergic neurons in the substantia nigra as assessed by stereology, which was accompanied by a loss of striatal dopaminergic terminals. Even at these higher doses, however, females showed less inflammation, and less accumulation of α-synuclein and transferrin, possibly as a result of preserved autophagy. Thus, the bias toward increased male incidence of human Parkinson's disease is reflected in the rotenone model. Whether such sex differences will translate into differences in responses to mechanism-driven therapeutic interventions remains to be determined.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Female; Humans; Lysosomes; Male; Microglia; Parkinson Disease; Rats; Rats, Inbred Lew; Rotenone; Sex Factors; Substantia Nigra; Transferrin; Tyrosine 3-Monooxygenase

Multiple system atrophy (MSA) is an adult-onset neurodegenerative disorder clinically characterized by autonomic failure in addition to various combinations of symptoms of parkinsonism, cerebellar ataxia, and pyramidal dysfunction. Despite extensive research, the mechanisms underlying the progression of MSA remain unknown. Animal models of human diseases that recapitulate their clinical, biochemical and pathological features are indispensable for increasing our understanding of their underlying molecular mechanisms, which allows preclinical studies to be advanced. Because the onset of MSA occurs in middle age, an animal model that first manifests abnormal protein aggregates in adulthood would be most appropriate. We therefore used the Cre-loxP system to express inducible α-synuclein (Syn), a major component of the pathological hallmark of MSA, to generate a mouse model of MSA. Beginning in adulthood, these MSA model mice express excessive levels of Syn in oligodendrocytes, resulting in abnormal Syn accumulation and modifications similar to those observed in human MSA pathology. Additionally, MSA model mice exhibit some clinical features of MSA, including decreased motor activity. These findings suggest that this new mouse model of MSA represents a useful tool for analyzing the pathophysiological alterations that underlie the progression of this disease.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Mice, Transgenic; Motor Activity; Multiple System Atrophy; Oligodendroglia; Phosphorylation

The dopaminergic neurodegeneration in the substantia nigrapars compacta (SNpc) and striatum of the midbrain is the important pathological feature of Parkinson's disease (PD). It has been shown that autophagy and endoplasmic reticulum stress (ERS) are involved in the occurrence and development of PD. The neuropeptide Apelin-13 is neuroprotective in the neurological diseases such as PD, Alzheimer's disease and cerebral ischemic stroke. In the present work, we investigated the neuroprotective effects of Apelin-13 on ERS and autophagy in the dopaminergic neurodegeneration of SNpc of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP)-treated mice. The intranigral injection of Apelin-13 alleviated the behavioral dysfunction and dopaminergic neurodegeneration induced by MPTP. After the exposure to MPTP, the expression of tyrosine hydroxylase (TH) was significantly decreased as well as the increased α-synuclein expression, which was significantly reversed by the intranigral injection of Apelin-13. Also, Apelin-13 significantly reversed the decreasing autophagy induced by MPTP which was indicated by the up-regulation of LC3B-II and Beclin1 and down-regulation of p62. And MPTP-induced ERS such as IRE1α, XBP1s, CHOP and GRP78 was significantly inhibited by Apelin-13. Taken together, Apelin-13 protects dopaminergic neurons in MPTP-induced PD model mice in vivo through inhibiting ERS and promoting autophagy, which contributes to the therapy for PD in the future.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Apelin; Autophagy; Beclin-1; Brain; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Intercellular Signaling Peptides and Proteins; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinson Disease; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease is the most prevalent movement disorder. Currently, therapies are palliative with associated irreversible behavioural incompetence. Here, we investigated the ability of kolaviron (KV), an anti-inflammatory biflavonoid isolated form Garcinia kola seeds, to rescue striatal neuronal damage and redo-inflammation in rats exposed to rotenone (ROT). Aged rats exposed to 11 days of rotenone intoxication were treated with KV either concurrently or for 18 days. The 18-day regimen included 7 days of pre-treatment prior 11-day concurrent ROT-KV treatment. Rotenone-exposed rats lost weight appreciably and travelled less distance with reduced speed, decline efficiency to maintain a straight path, enhanced freezing, increased immobile episodes and poor hole recognition. The motor incompetence was attributed to enhanced striatal neurodegeneration, increased alpha synuclein formation and reduced tyrosine hydroxylase expression. ROT intoxication significantly increased reactive species production, which co-existed with induction of striatal antioxidant system and damage to biomolecules. ROT additionally upregulated COX-2 expression, enhanced myeloperoxidase activity and increased concentration of striatal inteleukine-6 (IL-6), IL-1β and tumour necrosis factor (TNF-α). Treatment with kolaviron reversed the rotenone-associated locomotor impairment and exploratory deficits, motor/neuromuscular incompetence, striatal neurodegeneration, neurobiochemical imbalance, altered antioxidant defence system and neuroinflammation. KV-treated rats showed improved capacity to maintain efficient gait with minimal rigidity and enhanced coordination. Taken together, kolaviron exhibited neuroprotective properties, which may be beneficial for the prevention and management of Parkinson's disease, via antioxidant, anti-inflammatory and anti-apoptotic mechanisms.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Antiparkinson Agents; Apoptosis; Behavior, Animal; Corpus Striatum; Cytokines; Disease Models, Animal; Exploratory Behavior; Flavonoids; Inflammation Mediators; Locomotion; Male; Neurons; Neuroprotective Agents; Oxidative Stress; Parkinsonian Disorders; Rats, Wistar; Reactive Oxygen Species; Rotenone; Tyrosine 3-Monooxygenase

Topics: alpha-Synuclein; Animals; CA3 Region, Hippocampal; Cells, Cultured; Disease Models, Animal; Disks Large Homolog 4 Protein; Gene Knockdown Techniques; Ginsenosides; Hippocampus; Male; Memory; Mice; Mice, Inbred C57BL; MPTP Poisoning; Neuronal Plasticity; Neuroprotective Agents; Parkinsonian Disorders; Signal Transduction; Synaptic Transmission

Parkinson's disease (PD), a progressive neurodegenerative disease, is caused by the loss of dopaminergic neurons in the substantia nigra (SN). It is characterized by the formation of intracytoplasmic Lewy bodies that are primarily composed of the protein alpha-synuclein (

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Acupuncture Therapy; alpha-Synuclein; Animals; Chronic Disease; Corpus Striatum; Disease Models, Animal; Gene Expression; Immediate-Early Proteins; Immunohistochemistry; Male; Mice, Inbred C57BL; Parkinsonian Disorders; Protein Serine-Threonine Kinases; Substantia Nigra

Parkinson's disease is characterized by a proteinopathy that includes aggregates of α-synuclein. A recent hypothesis proposes a prion-like spreading mechanism for this α-synucleinopathy. Early neuropathological deposits occur, among others, in the anterior olfactory nucleus (AON). This study investigates the anterograde and/or retrograde transmissibility of exogenous α-synuclein inoculated in the right AON of the A53T model of Parkinson's disease and wild-type mice as well as neuronal and glial involvement. Seven experimental groups were established: wild-type injected with tracers; A53T mice injected with either α-synuclein or saline 2 months beforehand; wild-type injected with either α-synuclein or saline 2 months beforehand; and wild-type injected with either α-synuclein or saline 4 months beforehand. Weight and behavioral changes were analyzed. Immunohistochemistry against α-synuclein, NeuN, Iba-1 and GFAP was performed. Volume and marker distributions in the olfactory bulb (OB), AON and piriform cortex were analyzed using unbiased stereology. The behavioral analyses reveal higher levels of hyperactivity in transgenic as compared to wild-type mice. Tract-tracing experiments show that the main contralateral afferent projections to the dorsal AON come from the AON and secondarily from the OB. In saline-injected transgenic animals, α-synuclein expression in the OB and the AON is higher in the left hemisphere than in the right hemisphere, which could be due to basal interhemispheric differences. α-synuclein injection could provoke a significant increase in the left hemisphere of the transgenic mice's OB, compared to saline-injected animals. Neuronal loss was observed in saline-injected transgenic mice relative to the saline-injected wild-type group. There were no overall differences in neuron number following injection of α-synuclein into either wild-type or transgenic mice, however some neuron loss was apparent in specific regions of α-synuclein injected wild-types. Microglia labeling appeared to be correlated with surgery-induced inflammation. Astroglial labeling was higher in transgenic animals, which could be due to endogenous α-synucleinopathy. This study suggests α-synucleinopathy induction, via retrograde and contralateral projections, within the olfactory system of transgenic animals.

Topics: alpha-Synuclein; Animals; Astrocytes; Disease Models, Animal; Encephalitis; Male; Mice, Transgenic; Microglia; Neurons; Olfactory Cortex; Parkinson Disease

Parkinson's disease (PD) is pathologically characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and alpha-synucleinopathy. We mimic the disease pathology with overexpression of either the human α-syn wildtype (α-syn-WT) or E46K mutant form (α-syn-E46K) in DA neurons of the SNpc in adult rats using AAV2/DJ as a viral vector for the first time. Transduction efficiency was compared to an equal virus titer expressing the green fluorescent protein (GFP). Motor skills of all animals were evaluated in the cylinder and amphetamine-induced rotation test over a total time period of 12 weeks. Additionally, stereological quantification of DA cells and striatal fiber density measurements were performed every 4 weeks after injection. Rats overexpressing α-syn-WT showed a progressive loss of DA neurons with 40% reduction after 12 weeks accompanied by a greater loss of striatal DA fibers. In contrast, α-syn-E46K led to this reduction after 4 weeks without further progress. Insoluble α-syn positive cytoplasmic inclusions were observed in both groups within DA neurons of the SNpc and VTA. In addition, both α-syn groups developed a characteristic worsening of the rotational behavior over time. However, only the α-syn-WT group reached statistically significant different values in the cylinder test. Summarizing these effects, we established a motor symptom animal model of PD by using AAV2/DJ in the brain for the first time. Thereby, overexpressing of α-syn-E46K mimicked a rather pre-symptomatic stage of the disease, while the α-syn-WT overexpressing animals imitated an early symptomatic stage of PD.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Female; Genetic Vectors; Parkinson Disease; Pars Compacta; Parvovirinae; Rats; Rats, Sprague-Dawley

Neurodegenerative diseases like Alzheimer's disease, Parkinson's disease and Huntington's disease manifest with the neuronal accumulation of toxic proteins. Since autophagy upregulation enhances the clearance of such proteins and ameliorates their toxicities in animal models, we and others have sought to re-position/re-profile existing compounds used in humans to identify those that may induce autophagy in the brain. A key challenge with this approach is to assess if any hits identified can induce neuronal autophagy at concentrations that would be seen in humans taking the drug for its conventional indication. Here we report that felodipine, an L-type calcium channel blocker and anti-hypertensive drug, induces autophagy and clears diverse aggregate-prone, neurodegenerative disease-associated proteins. Felodipine can clear mutant α-synuclein in mouse brains at plasma concentrations similar to those that would be seen in humans taking the drug. This is associated with neuroprotection in mice, suggesting the promise of this compound for use in neurodegeneration.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Cell Line; Cerebral Cortex; Disease Models, Animal; Drug Repositioning; Embryo, Mammalian; Embryo, Nonmammalian; Felodipine; Female; Humans; Induced Pluripotent Stem Cells; Male; Mice; Mice, Inbred C57BL; Mutation; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Primary Cell Culture; Swine; Swine, Miniature; Treatment Outcome; Zebrafish

Parkinson's disease (PD) is characterized by selective death of dopaminergic neurons in the substantia nigra, degeneration of the nigrostriatal pathway, increases in glutamatergic synapses in the striatum and aggregation of α-synuclein. Evidence suggests that oligomeric species of α-synuclein (αSO) are the genuine neurotoxins of PD. Although several studies have supported the direct neurotoxic effects of αSO on neurons, their effects on astrocytes have not been directly addressed. Astrocytes are essential to several steps of synapse formation and function, including secretion of synaptogenic factors, control of synaptic elimination and stabilization, secretion of neural/glial modulators, and modulation of extracellular ions, and neurotransmitter levels in the synaptic cleft. Here, we show that αSO induced the astrocyte reactivity and enhanced the synaptogenic capacity of human and murine astrocytes by increasing the levels of the known synaptogenic molecule transforming growth factor beta 1 (TGF-β1). Moreover, intracerebroventricular injection of αSO in mice increased the number of astrocytes, the density of excitatory synapses, and the levels of TGF-β1 in the striatum of injected animals. Inhibition of TGF-β1 signaling impaired the effect of the astrocyte-conditioned medium on glutamatergic synapse formation in vitro and on striatal synapse formation in vivo, whereas addition of TGF-β1 protected mesencephalic neurons against synapse loss triggered by αSO. Together, our data suggest that αSO have important effects on astrocytic functions and describe TGF-β1 as a new endogenous astrocyte-derived molecule involved in the increase in striatal glutamatergic synaptic density present in early stages of PD. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/. Cover Image for this issue: doi: 10.1111/jnc.14514.

Topics: alpha-Synuclein; Animals; Astrocytes; Disease Models, Animal; Humans; Mice; Neurogenesis; Parkinsonian Disorders; Signal Transduction; Synapses; Transforming Growth Factor beta1

Multiple system atrophy (MSA) is characterized by the presence of distinctive glial cytoplasmic inclusions (GCIs) within oligodendrocytes that contain the neuronal protein alpha-synuclein (aSyn) and the oligodendroglia-specific phosphoprotein TPPP/p25α. However, the role of oligodendroglial aSyn and p25α in the formation of aSyn-rich GCIs remains unclear. To address this conundrum, we have applied human aSyn (haSyn) pre-formed fibrils (PFFs) to rat wild-type (WT)-, haSyn-, or p25α-overexpressing oligodendroglial cells and to primary differentiated oligodendrocytes derived from WT, knockout (KO)-aSyn, and PLP-haSyn-transgenic mice. HaSyn PFFs are readily taken up by oligodendroglial cells and can recruit minute amounts of endogenous aSyn into the formation of insoluble, highly aggregated, pathological assemblies. The overexpression of haSyn or p25α accelerates the recruitment of endogenous protein and the generation of such aberrant species. In haSyn PFF-treated primary oligodendrocytes, the microtubule and myelin networks are disrupted, thus recapitulating a pathological hallmark of MSA, in a manner totally dependent upon the seeding of endogenous aSyn. Furthermore, using oligodendroglial and primary cortical cultures, we demonstrated that pathology-related S129 aSyn phosphorylation depends on aSyn and p25α protein load and may involve different aSyn "strains" present in oligodendroglial and neuronal synucleinopathies. Importantly, this hypothesis was further supported by data obtained from human post-mortem brain material derived from patients with MSA and dementia with Lewy bodies. Finally, delivery of haSyn PFFs into the mouse brain led to the formation of aberrant aSyn forms, including the endogenous protein, within oligodendroglia and evoked myelin decompaction in WT mice, but not in KO-aSyn mice. This line of research highlights the role of endogenous aSyn and p25α in the formation of pathological aSyn assemblies in oligodendrocytes and provides in vivo evidence of the contribution of oligodendroglial aSyn in the establishment of aSyn pathology in MSA.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Multiple System Atrophy; Nerve Tissue Proteins; Neurons; Oligodendroglia; Rats; Synucleinopathies

Evidence is accumulating to suggest that viral infections and consequent viral-mediated neuroinflammation may contribute to the etiology of idiopathic Parkinson's disease. Moreover, viruses have been shown to influence α-synuclein oligomerization as well as the autophagic clearance of abnormal intra-cellular proteins aggregations, both of which are key neuropathological events in Parkinson's disease pathogenesis. To further investigate the interaction between viral-mediated neuroinflammation and α-synuclein aggregation in the context of Parkinson's disease, this study sought to determine the impact of viral neuroinflammatory priming on α-synuclein aggregate-induced neuroinflammation and neurotoxicity in the rat nigrostriatal pathway. To do so, male Sprague-Dawley rats were intra-nigrally injected with a synthetic mimetic of viral dsRNA (poly I:C) followed two weeks later by a peptidomimetic small molecule which accelerates α-synuclein fibril formation (FN075). The impact of the viral priming on α-synuclein aggregation-induced neuroinflammation, neurodegeneration and motor dysfunction was assessed. We found that prior administration of the viral mimetic poly I:C significantly exacerbated or precipitated the α-synuclein aggregate induced neuropathological and behavioral effects. Specifically, sequential exposure to the two challenges caused a significant increase in nigral microgliosis (p < 0.001) and astrocytosis (p < 0.01); precipitated a significant degeneration of the nigrostriatal cell bodies (p < 0.05); and precipitated a significant impairment in forelimb kinesis (p < 0.01) and sensorimotor integration (p < 0.01). The enhanced sensitivity of the nigrostriatal neurons to pathological α-synuclein aggregation after viral neuroinflammatory priming further suggests that viral infections may contribute to the etiology and pathogenesis of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Biomimetic Materials; Corpus Striatum; Dependovirus; Disease Models, Animal; Genetic Vectors; Gliosis; Male; Motor Activity; Neurodegenerative Diseases; Neuroimmunomodulation; Neurons; Parkinson Disease; Poly I-C; Protein Aggregation, Pathological; Rats; Rats, Sprague-Dawley; Substantia Nigra; Tyrosine 3-Monooxygenase

Persistent microglia-mediated neuroinflammation is a major pathophysiological contributor to the progression of Parkinson's disease (PD), but the cell-signaling mechanisms governing chronic neuroinflammation are not well understood. Here, we show that Fyn kinase, in conjunction with the class B scavenger receptor CD36, regulates the microglial uptake of aggregated human α-synuclein (αSyn), which is the major component of PD-associated Lewy bodies. αSyn can effectively mediate LPS-independent priming and activation of the microglial NLRP3 inflammasome. Fyn kinase regulates both of these processes; it mediates PKCδ-dependent NF-κB-p65 nuclear translocation, leading to inflammasome priming, and facilitates αSyn import into microglia, contributing to the generation of mitochondrial reactive oxygen species and consequently to inflammasome activation. In vivo experiments using A53T and viral-αSyn overexpression mouse models as well as human PD neuropathological results further confirm the role of Fyn in NLRP3 inflammasome activation. Collectively, our study identifies a novel Fyn-mediated signaling mechanism that amplifies neuroinflammation in PD.

Topics: alpha-Synuclein; Animals; CD36 Antigens; Dependovirus; Disease Models, Animal; Enzyme Activation; Gliosis; Humans; Inflammasomes; Interleukin-1beta; Mice, Inbred C57BL; Microglia; Mitochondria; Models, Biological; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Parkinson Disease; Protein Aggregates; Protein Folding; Protein Kinase C-delta; Proto-Oncogene Proteins c-fyn; Reactive Oxygen Species

The pathological process of Parkinson's disease (PD) is closely associated with the death of nigral neurons, for which an effective treatment has yet to be found. Lithium, one of the most widely certified anticonvulsant and mood‑stabilizing agents, exhibits evident neuroprotective effects in the treatment of epilepsy and bipolar disorder. In the present study, the neuroprotective mechanisms by which lithium acts on a chronic 1‑methyl‑4‑phenyl‑1,2,3,6‑tetrahydropyridine (MPTP) mouse model of PD were investigated by employing animal behavioral tests, immunohistochemistry, RT‑PCR, and western blotting. The results revealed that, in open field tests, lithium treatment counteracted the reduction in movement distance as well as activity time induced by MPTP administration. The compound could also prolong the drop time of MPTP‑treated mice in rotarod tests. Moreover, lithium treatment corrected the loss of nigral neurons, the increase of α‑synuclein (SNCA) in substantia nigra as well as in the striatum of MPTP‑treated mice, and decreased the methylation of SNCA intron 1 in DNA from the same regions. Furthermore, marked changes were observed in the expression of miRNAs including miR‑148a, a potential inhibitor of DNMT1, in the MPTP‑treated mice. These results suggested that the early application of lithium was important for alleviating the behavioral deficits experienced in the PD model, and that the neuroprotective action of lithium was achieved through a lithium‑triggered miRNA regulation mechanism. Essentially, our findings indicated that lithium may be beneficial in the prevention and treatment of PD through the regulation of α‑synuclein methylation.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; DNA (Cytosine-5-)-Methyltransferase 1; Introns; Lithium; Male; Methylation; Mice; Mice, Inbred C57BL; MicroRNAs; MPTP Poisoning; Neuroprotective Agents; Substantia Nigra

Axonal pathology precedes dopaminergic cell loss in Parkinson's disease (PD), indicating a dying back axonopathy of nigrostriatal projections. Although most attention focused on the dopaminergic system, increasing evidence implies a compromised serotonergic system in PD as well. By combining immunohistological and biochemical approaches, a profound layer-specific reduction of the serotonergic input to the prefrontal cortex (PFC) layers II and V/VI in aged mutant A53T α-synuclein-expressing mice (A53T mice) was detected. In addition, the altered fiber network was characterized by swollen axons and enlarged axonal varicosities within all PFC layers, but most pronounced in PFC layer I. Although prefrontal serotonin levels and synaptic protein expression were preserved, aged A53T mice showed increased levels of kinesin family member 1a and vesicular monoamine transporter 2. Together with increased tryptophan hydroxylase 2 mRNA levels in the raphe nuclei and an elevated serotonin receptor 1b expression in the PFC, these findings point to compensatory mechanisms within the serotonergic system to overcome the reduced neuritic input to the PFC in this transgenic animal model for PD.

Topics: Aging; alpha-Synuclein; Animals; Axons; Disease Models, Animal; Mice; Nerve Degeneration; Parkinson Disease; Prefrontal Cortex; Serotonergic Neurons

Emerging findings suggest that Parkinson's disease (PD) pathology (α-synuclein accumulation) and neuronal dysfunction may occur first in peripheral neurons of the autonomic nervous system including the enteric branches of the vagus nerve. The risk of PD increases greatly in people over the age of 65, a period of life in which chronic inflammation is common in many organ systems including the gut. Here we report that chronic mild focal intestinal inflammation accelerates the age of disease onset in α-synuclein mutant PD mice. Wild-type and PD mice treated with 0.5% dextran sodium sulfate (DSS) in their drinking water for 12 weeks beginning at 3 months of age exhibited histological and biochemical features of mild gut inflammation. The age of onset of motor dysfunction, evaluated using a rotarod test, gait analysis, and grip strength measurements, was significantly earlier in DSS-treated PD mice compared to control PD mice. Levels of the dopaminergic neuron marker tyrosine hydroxylase in the striatum and numbers of dopaminergic neurons in the substantia nigra were reduced in PD mice with gut inflammation. Levels of total and phosphorylated α-synuclein were elevated in enteric and brain neurons in DSS-treated PD mice, suggesting that mild gut inflammation accelerates α-synuclein pathology. Markers of inflammation in the colon and brain, but not in the blood, were elevated in DSS-treated PD mice, consistent with retrograde transneuronal propagation of α-synuclein pathology and neuroinflammation from the gut to the brain. Our findings suggest that interventions that reduce gut inflammation may prove beneficial in the prevention and treatment of PD.

Topics: alpha-Synuclein; Animals; Brain; Colitis; Colon; Corpus Striatum; Cytokines; Dextran Sulfate; Disease Models, Animal; Dopaminergic Neurons; Enteritis; Female; Gait Disorders, Neurologic; Hand Strength; Humans; Intestine, Small; Male; Mice; Mice, Knockout; Mutation, Missense; Nerve Tissue Proteins; Parkinsonian Disorders; Rotarod Performance Test; Substantia Nigra; Synucleinopathies; Tyrosine 3-Monooxygenase

α-synuclein (αS) is the major component of several types of brain pathological inclusions that define neurodegenerative diseases termed synucleinopathies. Central nervous system (CNS) inoculation studies using either in vitro polymerized αS fibrils or in vivo derived lysates containing αS aggregates to induce the progressive spread of αS inclusion pathology in animal disease models have supported the notion that αS mediated progressive neurodegeneration can occur by a prion-like mechanism. We have previously shown that neonatal brain inoculation with preformed αS fibrils in hemizygous M20

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Astrocytes; Brain; Disease Models, Animal; Humans; Inclusion Bodies; Mice, Transgenic; Microglia; Middle Aged; Multiple System Atrophy; Neurons; Synucleinopathies

Parkinson disease (PD) is a leading neurodegenerative disease, with multifaceted interacting mechanisms. The Thy1-aSyn mouse model of PD exhibits many features of PD patients, including sensorimotor and olfactory dysfunction and protein aggregation. Here, we tested the hypothesis that the dipeptide carnosine, which has anti-aggregating and metal-chelating properties, would provide beneficial effects on the motor and olfactory deficits observed in Thy1-aSyn mice. After 2 months of daily treatment with either intranasal (2 mg/day) or oral (10 mM in drinking water) carnosine, Thy1-aSyn mice and wild-type BDF1 mice were assessed for sensorimotor (challenging beam traversal test and spontaneous activity) and olfactory (buried pellet test) function. In addition, the olfactory epithelium was evaluated immunohistochemically for expression of alpha-synuclein (aSyn) and the carnosine transporter Pept2. Olfactory function was unaffected by carnosine treatment via either administration route. In contrast, intranasal carnosine prevented the normal decline in gait function seen in the challenging beam test in the Thy1-aSyn mice. Moreover, carnosine-treated Thy1-aSyn mice exhibited decreased aSyn immunostaining in the olfactory epithelium compared to vehicle-treated Thy1-aSyn mice, and the carnosine transporter Pept2 was immunolocalized to the apical surface of the olfactory epithelium. These findings demonstrate that intranasal carnosine shows promise in slowing the progression of motor deficits and aSyn deposition in PD.

Topics: alpha-Synuclein; Animals; Carnosine; Disease Models, Animal; Mice; Mice, Transgenic; Motor Activity; Parkinson Disease; Smell; Treatment Outcome

Parkinson's disease (PD) is a neurodegenerative disorder characterized by fibrillar neuronal inclusions composed of aggregated α-synuclein (α-syn). These inclusions are associated with behavioral and pathological PD phenotypes. One strategy for therapeutic interventions is to prevent the formation of these inclusions to halt disease progression. α-Synuclein exists in multiple structural forms, including disordered, nonamyloid oligomers, ordered amyloid oligomers, and fibrils. It is critical to understand which conformers contribute to specific PD phenotypes. Here, we utilized a mouse model to explore the pathological effects of stable β-amyloid-sheet oligomers compared with those of fibrillar α-synuclein. We biophysically characterized these species with transmission EM, atomic-force microscopy, CD spectroscopy, FTIR spectroscopy, analytical ultracentrifugation, and thioflavin T assays. We then injected these different α-synuclein forms into the mouse striatum to determine their ability to induce PD-related phenotypes. We found that β-sheet oligomers produce a small but significant loss of dopamine neurons in the substantia nigra pars compacta (SNc). Injection of small β-sheet fibril fragments, however, produced the most robust phenotypes, including reduction of striatal dopamine terminals, SNc loss of dopamine neurons, and motor-behavior defects. We conclude that although the β-sheet oligomers cause some toxicity, the potent effects of the short fibrillar fragments can be attributed to their ability to recruit monomeric α-synuclein and spread

Topics: alpha-Synuclein; Amyloid; Animals; Behavior, Animal; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Male; Mice; Parkinson Disease; Phenotype; Protein Aggregates; Protein Conformation, beta-Strand

Parkinson's disease (PD) is characterized by the presence of α-synuclein aggregates known as Lewy bodies and Lewy neurites, whose formation is linked to disease development. The causal relation between α-synuclein aggregates and PD is not well understood. We generated a new transgenic mouse line (MI2) expressing human, aggregation-prone truncated 1-120 α-synuclein under the control of the tyrosine hydroxylase promoter. MI2 mice exhibit progressive aggregation of α-synuclein in dopaminergic neurons of the substantia nigra pars compacta and their striatal terminals. This is associated with a progressive reduction of striatal dopamine release, reduced striatal innervation and significant nigral dopaminergic nerve cell death starting from 6 and 12 months of age, respectively. In the MI2 mice, alterations in gait impairment can be detected by the DigiGait test from 9 months of age, while gross motor deficit was detected by rotarod test at 20 months of age when 50% of dopaminergic neurons in the substantia nigra pars compacta are lost. These changes were associated with an increase in the number and density of 20-500 nm α-synuclein species as shown by dSTORM. Treatment with the oligomer modulator anle138b, from 9 to 12 months of age, restored striatal dopamine release, prevented dopaminergic cell death and gait impairment. These effects were associated with a reduction of the inner density of large α-synuclein aggregates and an increase in dispersed small α-synuclein species as revealed by dSTORM. The MI2 mouse model recapitulates the progressive dopaminergic deficit observed in PD, showing that early synaptic dysfunction is associated to fine behavioral motor alterations, precedes dopaminergic axonal loss and neuronal death that become associated with a more consistent motor deficit upon reaching a certain threshold. Our data also provide new mechanistic insight for the effect of anle138b's function in vivo supporting that targeting α-synuclein aggregation is a promising therapeutic approach for PD.

Topics: alpha-Synuclein; Animals; Cell Death; Disease Models, Animal; Dopaminergic Neurons; Gait; Mice; Mice, Transgenic; Motor Activity; Parkinson Disease; Protein Aggregation, Pathological; Substantia Nigra; Tyrosine 3-Monooxygenase

While GM1 may interact with α-synuclein in vitro to inhibit aggregation, the ability of GM1 to protect against α-synuclein toxicity in vivo has not been investigated. We used targeted adeno-associated viral vector (AAV) overexpression of human mutant α-synuclein (A53T) in the rat substantia nigra (SN) to produce degeneration of SN dopamine neurons, loss of striatal dopamine levels, and behavioral impairment. Some animals received daily GM1 ganglioside administration for 6 weeks, beginning 24 hours after AAV-A53T administration or delayed start GM1 administration for 5 weeks beginning 3 weeks after AAV-A53T administration. Both types of GM1 administration protected against loss of SN dopamine neurons and striatal dopamine levels, reduced α-synuclein aggregation, and delayed start administration of GM1 reversed early appearing behavioral deficits. These results extend prior positive results in MPTP models, are consistent with the results of a small clinical study of GM1 in PD patients that showed slowing of symptom progression with chronic use, and argue for the continued refinement and development of GM1 as a potential disease modifying therapy for PD.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Corpus Striatum; Dependovirus; Disease Models, Animal; Dopamine; Dopaminergic Neurons; G(M1) Ganglioside; Gene Expression Regulation; Genetic Vectors; Humans; Neuroprotective Agents; Parkinson Disease; Rats; Substantia Nigra

Parkinson's disease, a chronic, age related neurodegenerative disorder, is characterized by a progressive loss of nigrostriatal dopaminergic neurons. Several studies have proven that the activation of glial cells, presence of alpha-synuclein aggregates, and oxidative stress, fuels neurodegeneration, and currently there is no definitive treatment for PD. In this study, a rotenone-induced rat model of PD was used to understand the neuroprotective potential of Lycopodium (Lyc), a commonly-used potent herbal medicine. Immunohistochemcial data showed that rotenone injections significantly increased the loss of dopaminergic neurons in the substantia nigra, and decreased the striatal expression of tyrosine hydroxylase. Further, rotenone administration activated microglia and astroglia, which in turn upregulated the expression of α-synuclein, pro-inflammatory, and oxidative stress factors, resulting in PD pathology. However, rotenone-injected rats that were orally treated with lycopodium (50 mg/kg) were protected against dopaminergic neuronal loss by diminishing the expression of matrix metalloproteinase-3 (MMP-3) and MMP-9, as well as reduced activation of microglia and astrocytes. This neuroprotective mechanism not only involves reduction in pro-inflammatory response and α-synuclein expression, but also synergistically enhanced antioxidant defense system by virtue of the drug's multimodal action. These findings suggest that Lyc has the potential to be further developed as a therapeutic candidate for PD.

Topics: alpha-Synuclein; Animals; Antioxidants; Brain; Catalase; Cyclooxygenase 2; Cytokines; Disease Models, Animal; Dopaminergic Neurons; Glutathione; Inflammation; Inflammation Mediators; Lipid Peroxidation; Lycopodium; Male; Malondialdehyde; Matrix Metalloproteinases; Microglia; Nerve Degeneration; Neuroprotection; Nitric Oxide; Nitric Oxide Synthase Type II; Nitrites; Oxidative Stress; Parkinson Disease; Plant Extracts; Rats, Wistar; Rotenone; Superoxide Dismutase

Gastrointestinal (GI) motility dysfunction is the most common non-motor symptom of Parkinson's disease (PD). Studies have indicated that GI motility functions are impaired before the onset of PD.. To investigate the underlying mechanism of PD-induced GI dysmotility in MPTP (1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine)-induced animal model.. C57BL/6 mice were administered with or without a selective dopamine neurotoxin, MPTP, to induce parkinsonian symptoms. In addition to in vivo studies, in vitro experiments were also conducted in colon specimens using l-methyl-4-phenylpyridinium (MPP. MPTP-induced PD mice showed decreased expression of nuclear factor erythroid 2-related factor (Nrf2) and its target phase II genes in gastric and colon neuromuscular tissues. Decreased levels of tetrahydrobiopterin (BH

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Biopterins; Blotting, Western; Colon; Constipation; Disease Models, Animal; Enzyme Inhibitors; Gastric Emptying; Gastrointestinal Motility; Gene Expression Regulation; Heme Oxygenase-1; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; MPTP Poisoning; NF-E2-Related Factor 2; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase Type I; Parkinson Disease; Parkinsonian Disorders; Tyrosine 3-Monooxygenase

The aims of this study were to investigate the effect of colonic electrical stimulation (CES) on delayed colonic transit in Parkinson's disease (PD) model induced by rotenone and its possible mechanisms.. Sprague-Dawley male rats were implanted with a pair of electrodes on the serosa at the proximal colon and rotenone was subcutaneously injected for 6 weeks to induce the PD model. Behavior activity, stool volume and open-field test were recorded during the injection. Colonic propulsion rate was measured 6 weeks after rotenone injection. Colon samples of all rats were collected for the measurement of phosphorylated alpha-synuclein, choline acetyltransferase (CHAT), neuronal nitric oxide synthase (nNOS), and tyrosine hydroxylase (TH). The protocols of control rats were the same as the PD rats except that no electrodes were implanted and no rotenone was injected.. (1) Rotenone-induced PD rats demonstrated weight loss, significant decrease of the dopaminergic neurons in substantia nigra, and impairment of colon movement. (2) CES significantly accelerated the delayed colonic transmit (91.67 ± 5.58% vs 51.33 ± 4.18%), superior to Macrogol-4000. (3) CES significantly upregulated the expression of CHAT, nNOS and TH protein in colon of PD rats. (4) In colon of PD rats, the phosphorylated alpha-synuclein was significantly upregulated, but CES had no significant effect on phosphorylated alpha-synuclein.. Our data show that CES can normalize the delayed colonic transit and this normalization may attribute to affecting enteric excitatory and inhibitory neurons.

Topics: alpha-Synuclein; Animals; Choline O-Acetyltransferase; Colon; Constipation; Disease Models, Animal; Electric Stimulation; Enteric Nervous System; Gastrointestinal Motility; Intestine, Small; Male; Neurons; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Parkinson Disease; Rats; Rats, Sprague-Dawley; Rotenone; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease and related disorders are neuropathologically characterized by cellular deposits of misfolded and aggregated α-synuclein in the CNS. Disease-associated α-synuclein adopts a conformation that causes it to form oligomers and fibrils, which have reduced solubility, become hyperphosphorylated, and contribute to the spatiotemporal spreading of pathology in the CNS. The infectious properties of disease-associated α-synuclein, e.g., by which peripheral route and with which efficiency it can be transmitted, are not fully understood. Here, we investigated the potential of α-synuclein fibrils to induce neurological disease in TgM83

Topics: Administration, Intravenous; Administration, Oral; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Mice; Phosphorylation; Synucleinopathies

Parkinson's disease (PD) is one of the most common neurodegenerative diseases, which is characterized by progressive motor dysfunction as well as non-motor symptoms. Pathological and genetic studies have demonstrated that α-synuclein (αSyn) plays key roles in the pathogenesis of PD. Although several missense mutations in the αSyn gene have been identified as causes of familial PD, the mechanisms underlying the variance in the clinical phenotypes of familial PD caused by different mutations remain elusive. Here, we established novel Drosophila models expressing either wild-type (WT) αSyn or one of five αSyn mutants (A30P, E46K, H50Q, G51D, and A53T) using site-specific transgenesis, which express transgenes at equivalent levels. Expression of either WT or mutant αSyn in the compound eyes by the GMR-GAL4 driver caused mild rough eye phenotypes with no obvious difference among the mutants. Upon pan-neuronal expression by the nSyb-GAL4 driver, these αSyn-expressing flies showed a progressive decline in locomotor function. Notably, we found that E46K, H50Q, G51D, and A53T αSyn-expressing flies showed earlier onset of locomotor dysfunction than WT αSyn-expressing flies, suggesting their enhanced toxic effects. Whereas mRNA levels of WT and mutant αSyn were almost equivalent, we found that protein expression levels of E46K αSyn were higher than those of WT αSyn. In vivo chase experiments using the drug-inducible GMR-GeneSwitch driver demonstrated that degradation of E46K αSyn protein was significantly slower than WT αSyn protein, indicating that the E46K αSyn mutant gains resistance to degradation in vivo. We therefore conclude that our novel site-specific transgenic fly models expressing either WT or mutant αSyn are useful to explore the mechanisms by which different αSyn mutants gain toxic functions in vivo.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila; Humans; Mutation, Missense; Parkinson Disease; Proteolysis

The conversion of endogenous alpha-synuclein (asyn) to pathological asyn-enriched aggregates is a hallmark of Parkinson's disease (PD). These inclusions can be detected in the central and enteric nervous system (ENS). Moreover, gastrointestinal symptoms can appear up to 20 years before the diagnosis of PD. The dual-hit hypothesis posits that pathological asyn aggregation starts in the ENS, and retrogradely spreads to the brain. In this study, we tested this hypothesis by directly injecting preformed asyn fibrils into the duodenum wall of wild-type rats and transgenic rats with excess levels of human asyn. We provide a meticulous characterization of the bacterial artificial chromosome (BAC) transgenic rat model with respect to initial propagation of pathological asyn along the parasympathetic and sympathetic pathways to the brainstem, by performing immunohistochemistry at early time points post-injection. Induced pathology was observed in all key structures along the sympathetic and parasympathetic pathways (ENS, autonomic ganglia, intermediolateral nucleus of the spinal cord (IML), heart, dorsal motor nucleus of the vagus, and locus coeruleus (LC)) and persisted for at least 4 months post-injection. In contrast, asyn propagation was not detected in wild-type rats, nor in vehicle-injected BAC rats. The presence of pathology in the IML, LC, and heart indicate trans-synaptic spread of the pathology. Additionally, the observed asyn inclusions in the stomach and heart may indicate secondary anterograde propagation after initial retrograde spreading. In summary, trans-synaptic propagation of asyn in the BAC rat model is fully compatible with the "body-first hypothesis" of PD etiopathogenesis. To our knowledge, this is the first animal model evidence of asyn propagation to the heart, and the first indication of bidirectional asyn propagation via the vagus nerve, i.e., duodenum-to-brainstem-to-stomach. The BAC rat model could be very valuable for detailed mechanistic studies of the dual-hit hypothesis, and for studies of disease modifying therapies targeting early pathology in the gastrointestinal tract.

Topics: alpha-Synuclein; Animals; Autonomic Nervous System; Brain; Disease Models, Animal; Gastrointestinal Tract; Neurons; Parkinson Disease; Rats; Rats, Sprague-Dawley; Spinal Cord; Synapses

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drug Discovery; GPI-Linked Proteins; Humans; Neurodegenerative Diseases; Prions

Parkinson's disease (PD) is associated with olfactory defects in addition to dopaminergic degeneration. Dopaminergic signalling is necessary for subventricular zone (SVZ) proliferation and olfactory bulb (OB) neurogenesis. Alpha-synuclein (α-syn or Snca) modulates dopaminergic neurotransmission, and SNCA mutations cause familial PD, but how α-syn and its mutations affect adult neurogenesis is unclear. To address this, we studied a bacterial artificial chromosome transgenic mouse expressing the A30P SNCA familial PD point mutation on an Snca-/- background. We confirmed that the SNCA-A30P transgene recapitulates endogenous α-syn expression patterns and levels by immunohistochemical detection of endogenous α-syn in a wild-type mouse and transgenic SNCA-A30P α-syn protein in the forebrain. The number of SVZ stem cells (BrdU+GFAP+) was decreased in SNCA-A30P mice, whereas proliferating (phospho-histone 3+) cells were decreased in Snca-/- and even more so in SNCA-A30P mice. Similarly, SNCA-A30P mice had fewer Mash1+ transit-amplifying SVZ progenitor cells but Snca-/- mice did not. These data suggest the A30P mutation aggravates the effect of Snca loss in the SVZ. Interestingly, calbindin+ and calretinin (CalR)+ periglomerular neurons were decreased in both Snca-/-, and SNCA-A30P mice but tyrosine hydroxylase+ periglomerular OB neurons were only decreased in Snca-/- mice. Cell death decreased in the OB granule layer of Snca-/- and SNCA-A30P mice. In the same region, CalR+ numbers increased in Snca-/- and SNCA-A30P mice. Thus, α-syn loss and human A30P SNCA decrease SVZ proliferation, cell death in the OB and differentially alter interneuron numbers. Similar disruptions in human neurogenesis may contribute to the olfactory deficits, which are observed in PD.

Topics: alpha-Synuclein; Animals; Calbindin 2; Cell Death; Cell Proliferation; Disease Models, Animal; Dopamine; Humans; Interneurons; Lateral Ventricles; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurogenesis; Olfactory Bulb; Parkinson Disease; Point Mutation; Tyrosine 3-Monooxygenase

α-Synucleinopathies are neurodegenerative diseases that are characterized pathologically by α-synuclein inclusions in neurons and glia. The pathologic contribution of glial α-synuclein in these diseases is not well understood. Glial α-synuclein may be of particular importance in multiple system atrophy (MSA), which is defined pathologically by glial cytoplasmic α-synuclein inclusions. We have previously described Drosophila models of neuronal α-synucleinopathy, which recapitulate key features of the human disorders. We have now expanded our model to express human α-synuclein in glia. We demonstrate that expression of α-synuclein in glia alone results in α-synuclein aggregation, death of dopaminergic neurons, impaired locomotor function, and autonomic dysfunction. Furthermore, co-expression of α-synuclein in both neurons and glia worsens these phenotypes as compared to expression of α-synuclein in neurons alone. We identify unique transcriptomic signatures induced by glial as opposed to neuronal α-synuclein. These results suggest that glial α-synuclein may contribute to the burden of pathology in the α-synucleinopathies through a cell type-specific transcriptional program. This new Drosophila model system enables further mechanistic studies dissecting the contribution of glial and neuronal α-synuclein in vivo, potentially shedding light on mechanisms of disease that are especially relevant in MSA but also the α-synucleinopathies more broadly.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cell Death; Constipation; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Humans; Movement Disorders; Nerve Degeneration; Neurodegenerative Diseases; Neuroglia; Protein Aggregation, Pathological; Transcription, Genetic; Transcriptome

Animal models that accurately recapitulate the accumulation of alpha-synuclein (α-syn) inclusions, progressive neurodegeneration of the nigrostriatal system and motor deficits can be useful tools for Parkinson's disease (PD) research. The preformed fibril (PFF) synucleinopathy model in rodents generally displays these PD-relevant features, however, the magnitude and predictability of these events is far from established. We therefore sought to optimize the magnitude of α-syn accumulation and nigrostriatal degeneration, and to understand the time course of both. Rats were injected unilaterally with different quantities of α-syn PFFs (8 or 16 μg of total protein) into striatal sites selected to concentrate α-syn inclusion formation in the substantia nigra pars compacta (SNpc). Rats displayed an α-syn PFF quantity-dependent increase in the magnitude of ipsilateral SNpc inclusion formation at 2 months and bilateral loss of nigral dopamine neurons at 6 months. Unilateral 16 μg PFF injection also resulted in modest sensorimotor deficits in forelimb adjusting steps associated with degeneration at 6 months. Bilateral injection of 16 μg α-syn PFFs resulted in symmetric bilateral degeneration equivalent to the ipsilateral nigral degeneration observed following unilateral 16 μg PFF injection (~50% loss). Bilateral PFF injections additionally resulted in alterations in several gait analysis parameters. These α-syn PFF parameters can be applied to generate a reproducible synucleinopathy model in rats with which to study pathogenic mechanisms and vet potential disease-modifying therapies.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Inclusion Bodies; Male; Rats; Rats, Inbred F344; Substantia Nigra; Synucleinopathies

Multiple system atrophy (MSA) is a fatal, adult-onset neurodegenerative disorder that has no cure and very limited treatment options. MSA is characterized by deposition of fibrillar α-synuclein (α-syn) in glial cytoplasmic inclusions in oligodendrocytes. Similar to other synucleinopathies, α-syn self-assembly is thought to be a key pathologic event and a prominent target for disease modification in MSA. Molecular tweezers are broad-spectrum nanochaperones that prevent formation of toxic protein assemblies and enhance their clearance. The current lead compound, CLR01, has been shown to inhibit α-syn aggregation but has not yet been tested in the context of MSA. To fill this gap, here, we conducted a proof-of-concept study to assess the efficacy of CLR01 in remodeling MSA-like α-syn pathology in the PLP-α-syn mouse model of MSA. Six-month-old mice received intracerebroventricular CLR01 (0.3 or 1 mg/kg per day) or vehicle for 32 days. Open-field test revealed a significant, dose-dependent amelioration of an anxiety-like phenotype. Subsequently, immunohistochemical and biochemical analyses showed dose-dependent reduction of pathological and seeding-competent forms of α-syn, which correlated with the behavioral phenotype. CLR01 treatment also promoted dopaminergic neuron survival in the substantia nigra. To our knowledge, this is the first demonstration of an agent that reduces formation of putative high-molecular-weight oligomers and seeding-competent α-syn in a mouse model of MSA, supporting the view that these species are key to the neurodegenerative process and its cell-to-cell progression in MSA. Our study suggests that CLR01 is an attractive therapeutic candidate for disease modification in MSA and related synucleinopathies, supporting further preclinical development.

Topics: alpha-Synuclein; Animals; Brain; Bridged-Ring Compounds; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Mice; Multiple System Atrophy; Neuroprotective Agents; Organophosphates; Protein Aggregation, Pathological

Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces degeneration of dopaminergic neurons and reproduces the motor features of Parkinson disease (PD); however, the effect of MPTP on extranigral structures has been poorly studied. The aim of this research was to study the cardiac sympathetic innervation of control and MPTP-treated monkeys in order to describe the influence of MPTP toxicity on cardiac tissue.. Eight monkeys were included in the study and divided into two groups, four monkeys serving as controls and four forming the MPTP group. Sections from the anterior left ventricle were immunohistochemically examined to characterize the sympathetic fibers of cardiac tissue. The intensity of immunoreactivity in the nerve fibers was quantitatively analyzed using ImageJ software.. As occurs in PD, the sympathetic peripheral nervous system is affected in MPTP-treated monkeys. The percentage of tyrosine hydroxylase immunoreactive fibers in the entire fascicle area was markedly lower in the MPTP group (24.23%) than the control group (35.27%) (p < 0.05), with preservation of neurofilament immunoreactive fibers in the epicardium of MPTP-treated monkeys. Alpha-synuclein deposits were observed in sections of the anterior left ventricle of MPTP-treated monkeys but not in control animals, whereas phosphorylated synuclein aggregates were not observed in either controls or MPTP-treated monkeys.. The peripheral autonomic system can also be affected by neurotoxins that specifically inhibit mitochondrial complex I.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Heart; Macaca fascicularis; Male; MPTP Poisoning; Primates; Random Allocation; Sympathetic Nervous System

Variants in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) are known to increase the risk of developing Alzheimer disease and Parkinson's disease (PD). However, the potential role of TREM2 effect on synucleinopathy has not been characterized. In this study, we investigated whether loss of TREM2 function affects α-synucleinopathy both

Topics: alpha-Synuclein; Animals; Apoptosis; Cells, Cultured; Disease Models, Animal; Female; Inflammation; Male; Membrane Glycoproteins; Mice; Microglia; Parkinson Disease; Receptors, Immunologic; Signal Transduction

The pathological impact of chronic cerebral hypoperfusion (CCH) on Alzheimer's disease (AD) is still poorly understood. In the present study, we investigated the role of CCH on an AD mouse model in phosphorylated tau and α-synuclein pathology, neurovascular unit, cerebrovascular remodeling, and neurovascular trophic coupling. Moreover, examined protective effect of a new antioxidant Twendee X (TwX).. APP23 mice were implanted to bilateral common carotid arteries stenosis with ameroid constrictors to gradually decrease the cerebral blood flow. The effects of the administration of TwX were evaluated by immunohistochemical analysis and Immunofluorescent histochemistry.. Our findings indicate that administration of a new antioxidative mixture TwX substantially reduced the above neuropathologic abnormalities, suggesting a potential therapeutic benefit of TwX for AD with CCH.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Antioxidants; Ascorbic Acid; Brain; Cerebrovascular Disorders; Cystine; Dietary Supplements; Disease Models, Animal; Female; Genetic Predisposition to Disease; Glutamine; Male; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Neurovascular Coupling; Phenotype; Phosphorylation; tau Proteins

In multiple system atrophy (MSA), progressive neurodegeneration results from the protein α-synuclein misfolding into a self-templating prion conformation that spreads throughout the brain. MSA prions are transmissible to transgenic (Tg) mice expressing mutated human α-synuclein (TgM83

Topics: alpha-Synuclein; Animals; Biological Transport; Brain; Detergents; Disease Models, Animal; Fixatives; Formaldehyde; HEK293 Cells; Humans; Mice, Transgenic; Multiple System Atrophy; Muscle, Skeletal; Mutation; Prions; Protein Aggregates; Protein Stability; Sarcosine; Stainless Steel

Moderate physical exercise acts at molecular and behavioural levels, such as interfering in neuroplasticity, cell death, neurogenesis, cognition and motor functions. Therefore, the aim of this study is to analyse the cellular effects of moderate treadmill running upon substantia nigra during early neurodegeneration. Aged male Lewis rats (9-month-old) were exposed to rotenone 1mg/kg/day (8 weeks) and 6 weeks of moderate treadmill running, beginning 4 weeks after rotenone exposure. Substantia nigra was extracted and submitted to proteasome and antioxidant enzymes activities, hydrogen peroxide levels and Western blot to evaluate tyrosine hydroxylase (TH), alpha-synuclein, Tom-20, PINK1, TrkB, SLP1, CRMP-2, Rab-27b, LC3II and Beclin-1 level. It was demonstrated that moderate treadmill running, practiced during early neurodegeneration, prevented the increase of alpha-synuclein and maintained the levels of TH unaltered in substantia nigra of aged rats. Physical exercise also stimulated autophagy and prevented impairment of mitophagy, but decreased proteasome activity in rotenone-exposed aged rats. Physical activity also prevented H

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Hydrogen Peroxide; Male; Mitophagy; Neurodegenerative Diseases; Physical Conditioning, Animal; Proteasome Endopeptidase Complex; Rats, Inbred Lew; Rotenone; Running; Substantia Nigra; Tyrosine 3-Monooxygenase

Neuroinflammation mediated by chronically activated microglia, largely caused by abnormal accumulation of misfolded α-synuclein (αSyn) protein, is known to contribute to the pathophysiology of Parkinson's disease (PD). In this work, based on the immunomodulatory activities displayed by particular heat-shock proteins (HSPs), we tested a novel vaccination strategy that used a combination of αSyn and Grp94 (HSPC4 or Gp96) chaperone and a murine PD model. We used two different procedures, first, the adoptive transfer of splenocytes from αSyn/Grp94-immunized mice to recipient animals, and second, direct immunization with αSyn/Grp94, to study the effects in a chronic mouse MPTP-model of parkinsonism. We found that both approaches promoted a distinct profile in the peripheral system-supported by humoral and cellular immunity-consisting of a Th1-shifted αSyn-specific response accompanied by an immune-regulatory/Th2-skewed general phenotype. Remarkably, this mixed profile sustained by αSyn/Grp94 immunization led to strong suppression of microglial activation in the substantia nigra and striatum, pointing to a newly described positive effect of anti-αSyn Th1-responses in the context of PD. This strategy is the first to target αSyn and report the suppression of PD-associated microgliosis. Overall, we show that the αSyn/Grp94 combination supports a distinct and long-lasting immune profile in the peripheral system, which has an impact at the CNS level by suppressing chronic microglial activation in an MPTP model of PD. Furthermore, our study demonstrates that reshaping peripheral immunity by vaccination with appropriate misfolding protein/HSP combinations could be highly beneficial as a treatment for neurodegenerative misfolding diseases.

Topics: Adoptive Transfer; alpha-Synuclein; Analysis of Variance; Animals; CD4 Antigens; Chronic Disease; Cytokines; Disease Models, Animal; Gliosis; Immunization; Male; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Microglia; MPTP Poisoning; Substantia Nigra; T-Lymphocytes, Regulatory

Parkinson's disease (PD) pathology is characterized by the abnormal accumulation and aggregation of the pre-synaptic protein α-synuclein in the dopaminergic neurons as Lewy bodies (LBs). Curcumin, which plays a neuroprotective role in various animal models of PD, was found to directly modulate the aggregation of α-synuclein in in vitro as well as in in vivo studies. While curcumin has been shown to exhibit strong anti-oxidant and anti-inflammatory properties, there are a number of other possible mechanisms by which curcumin may alter α-synuclein aggregation which still remains obscure. Therefore, the present study was designed to understand such concealed mechanisms behind neuroprotective effects of curcumin. An animal model of PD was established by injecting lipopolysaccharide (LPS, 5 µg/5 µl PBS) into the substantia nigra (SN) of rats which was followed by curcumin administration (40 mg/kg b.wt (i.p.)) daily for a period of 21 days. Modulatory functions of curcumin were evident from the inhibition of astrocytic activation (GFAP) by immunofluorescence and NADPH oxidase complex activation by RT-PCR. Curcumin supplementation prevented the LPS-induced upregulation in the protein activity of transcription factor NFκB, proinflammatory cytokines (TNF-α, IL-1β, and IL-1α), inducible nitric oxide synthase (iNOS) as well as the regulating molecules of the intrinsic apoptotic pathway (Bax, Bcl-2, Caspase 3 and Caspase 9) by ELISA. Curcumin also resulted in significant improvement in the glutathione system (GSH, GSSG and redox ratio) and prevented iron deposition in the dopaminergic neurons as depicted from atomic absorption spectroscopy (AAS) and Prussian blue staining, respectively. Curcumin also prevented α-synuclein aggregates in the dopaminergic neurons as observed from gene as well as protein activity of α-synuclein using RT-PCR and IHC. Collectively, our results suggest that curcumin can be further pursued as a candidate drug in the molecules targeted therapy for PD and other related synucleopathies.

Topics: alpha-Synuclein; Animals; Apoptosis; Apoptosis Regulatory Proteins; Curcumin; Cytokines; Disease Models, Animal; Glutathione; Lipopolysaccharides; Male; Neuroprotection; Neuroprotective Agents; Parkinson Disease; Rats; Rats, Sprague-Dawley; Substantia Nigra

Neuromodulation of the globus pallidus internus(GPi) alleviates Parkinson's disease symptoms. The primate GPi is homologous to the rat entopeduncular nucleus (EP). The aim of the present study was to determine if optogenetic modulation of the EP could alter parkinsonian behavior or thalamic discharge in a hemiparkinson rat model.. We injected an adeno-associated virus type-2 expressing α-synuclein (AAV2-α-syn) into the substantia nigra pars compacta (SNc) of the right hemisphere and confirmed parkinsonian behavior using an amphetamine-induced rotation test. Then we injected activated or inhibited neurons, using the channelrhodopsin2 (ChR2)/halorhodopsin (NpHR) system in the EP of the hemiparkinson rat model and examined downstream effects in vivo. We assessed alterations in parkinsonian behaviors using the stepping and cylinder tests before, during, and after optogenetic stimulation.. Importantly, optogenetic inhibition of the EP improved parkinsonian motor behaviors. When we monitored thalamic neuronal activity following optogenetic neuromodulation in vivo, and we observed alterations in thalamic discharge The thalamic neuronal activity is increased for optogenetic inhibition stimulation, whereas decreased for optogenetic activation stimulation.. Taken together, our data demonstrate that optical neuromodulation of the EP can successfully control contralateral forelimb movement and thalamic discharge in an AAV2-α-synuclein-induced hemiparkinson rat model.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Entopeduncular Nucleus; Male; Motor Activity; Neural Pathways; Neurons; Optogenetics; Parkinson Disease; Rats, Sprague-Dawley; Substantia Nigra; Thalamus

In the adult mammalian hippocampus, new neurons are constantly added to the dentate gyrus. Adult neurogenesis is impaired in several neurodegenerative mouse models including α-synuclein (a-syn) transgenic mice. Among different a-syn species, a-syn oligomers were reported to be the most toxic species for neurons. Here, we studied the impact of wild-type vs. oligomer-prone a-syn on neurogenesis. We compared the wild-type a-syn transgenic mouse model (Thy1-WTS) to its equivalent transgenic for oligomer-prone E57K-mutant a-syn (Thy1-E57K). Transgenic a-syn was highly expressed within the hippocampus of both models, but was not present within adult neural stem cells and neuroblasts. Proliferation and survival of newly generated neurons were unchanged in both transgenic models. Thy1-WTS showed a minor integration deficit regarding mushroom spine density of newborn neurons, whereas Thy1-E57K exhibited a severe reduction of all spines. We conclude that cell-extrinsic a-syn impairs mushroom spine formation of adult newborn neurons and that oligomer-prone a-syn exacerbates this integration deficit. Moreover, our data suggest that a-syn reduces the survival of newborn neurons by a cell-intrinsic mechanism during the early neuroblast development. The finding of increased spine pathology in Thy1-E57K is a new pathogenic function of oligomeric a-syn and precedes overt neurodegeneration. Thus, it may constitute a readout for therapeutic approaches.

Topics: alpha-Synuclein; Animals; Bromodeoxyuridine; Caspase 3; Cell Proliferation; Disease Models, Animal; Doublecortin Domain Proteins; Gene Expression Regulation; Glutamic Acid; Hippocampus; Lysine; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microtubule-Associated Proteins; Mutation; Neurodegenerative Diseases; Neurogenesis; Neurons; Neuropeptides; Phosphopyruvate Hydratase; SOXB1 Transcription Factors

Alpha-Synuclein (α-Syn) accumulation is considered a major risk factor for the development of synucleinopathies such as Parkinson's disease (PD) and dementia with Lewy bodies. We have generated mice overexpressing full-length human α-Syn fused to a membrane-targeting signal sequence under the control of the mouse Thy1-promotor. Three separate lines (L56, L58 and L62) with similar gene expression levels, but considerably heightened protein accumulation in L58 and L62, were established. In L62, there was widespread labelling of α-Syn immunoreactivity in brain including spinal cord, basal forebrain, cortex and striatum. Interestingly, there was no detectable α-Syn expression in dopaminergic neurones of the substantia nigra, but strong human α-Syn reactivity in glutamatergic synapses. The human α-Syn accumulated during aging and formed PK-resistant, thioflavin-binding aggregates. Mice displayed early onset bradykinesia and age progressive motor deficits. Functional alterations within the striatum were confirmed: L62 showed normal basal dopamine levels, but impaired dopamine release (upon amphetamine challenge) in the dorsal striatum measured by in vivo brain dialysis at 9 months of age. This impairment was coincident with a reduced response to amphetamine in the activity test. L62 further displayed greater sensitivity to low doses of the dopamine receptor 1 (D1) agonist SKF81297 but reacted normally to the D2 agonist quinpirole in the open field. Since accumulation of α-Syn aggregates in neurones and synapses and alterations in the dopaminergic tone are characteristics of PD, phenotypes reported for L62 present a good opportunity to further our understanding of motor dysfunction in PD and Lewy body dementia.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Mice, Transgenic; Parkinson Disease; Phenotype; Substantia Nigra

Transgenic overexpression of α-synuclein is a common model of Parkinson's disease (PD). Accumulation of А53Т-mutant α-synuclein induces three autophagy cell responses: the inhibition of autophagy caused by the accumulation of α-synuclein, compensatory activation of macroautophagy in response to inhibition of the chaperone-mediated autophagy, and toxic effects of mutant α-synuclein accompanied by the activation of autophagy. The overall effect of long-term overexpression of mutant α-synuclein in vivo remains unclear. Here we evaluated the activity of autophagy in the frontal cortex, striatum and s.nigra of transgenic mice with overexpression of А53Т-mutant α-synuclein. We revealed low autophagic activity in the dopaminergic structures of 5 mo. transgenic B6.Cg-Tg(Prnp-SNCA*A53T)23Mkle/J mice as compared to controls C57Bl/6J mice. The results were further supported by the data on tyrosine hydroxylase immunostaining that indicated its significant decrease in the striatum but not in s.nigra of transgenic mice and might be more related to earlier damage of dopaminergic neurites than to the somas due to disturbed formation of autophagosomes at the neuron periphery. The results provide evidence of a possible contribution of suppressed autophagy to the development of PD-like condition as an early event at synucleinopathy progression. Activation of autophagy at early stages of PD seems to be a promising therapeutic tool while B6.Cg-Tg(Prnp-SNCA*A53T)23Mkle/J mice are suggested as a suitable and adequate model for studying the neuroprotective potential and value of this approach.

Topics: alpha-Synuclein; Animals; Autophagy; Corpus Striatum; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Frontal Lobe; Mice; Mice, Transgenic; Parkinson Disease; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease is characterized by degeneration of substantia nigra dopamine neurons and by intraneuronal aggregates, primarily composed of misfolded α-synuclein. The α-synuclein aggregates in Parkinson's patients are suggested to first appear in the olfactory bulb and enteric nerves and then propagate, following a stereotypic pattern, via neural pathways to numerous regions across the brain. We recently demonstrated that after injection of either mouse or human α-synuclein fibrils into the olfactory bulb of wild-type mice, α-synuclein fibrils recruited endogenous α-synuclein into pathological aggregates that spread transneuronally to over 40 other brain regions and subregions, over 12 months. We previously reported the progressive spreading of α-synuclein aggregates, between 1 and 12 months following α-synuclein fibril injections, and now report how far the pathology has spread 18- and 23-month post-injection in this model. Our data show that between 12 and 18 months, there is a further increase in the number of brain regions exhibiting pathology after human, and to a lesser extent mouse, α-synuclein fibril injections. At both 18 and 23 months after injection of mouse and human α-synuclein fibrils, we observed a reduction in the density of α-synuclein aggregates in some brain regions compared to others at 12 months. At 23 months, no additional brain regions exhibited α-synuclein aggregates compared to earlier time points. In addition, we also demonstrate that the induced α-synucleinopathy triggered a significant early neuron loss in the anterior olfactory nucleus. By contrast, there was no loss of mitral neurons in the olfactory bulb, even at 18 month post-injection. We speculate that the lack of continued progression of α-synuclein pathology is due to compromise of the neural circuitry, consequential to neuron loss and possibly to the activation of proteolytic mechanisms in resilient neurons of wild-type mice that counterbalances the spread and seeding by degrading pathogenic α-synuclein.

Topics: alpha-Synuclein; Animals; Biological Transport; Brain; Cell Death; Disease Models, Animal; Disease Progression; DNA-Binding Proteins; Female; Humans; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Olfactory Bulb; Protein Aggregation, Pathological; Recombinant Proteins; tau Proteins

In this study, we analyze the neuropathological and biochemical alterations involved in the pathogenesis of a neurodegenerative/movement disorder during different developmental stages in juvenile rats with a mutant Myosin5a (Myo5a). In mutant rats, a spontaneous autosomal recessive mutation characterized by the absence of Myo5a protein expression in the brain is associated with a syndrome of locomotor dysfunction, altered coat color, and neuroendocrine abnormalities. Myo5a encodes a myosin motor protein required for transport and proper distribution of subcellular organelles in somatodendritic processes in neurons. Here we report marked hyperphosphorylation of alpha-synuclein and tau, as well as region-specific buildup of the autotoxic dopamine metabolite, 3,4-dihydroxyphenyl-acetaldehyde (DOPAL), related to decreased aldehyde dehydrogenases activity and neurodegeneration in mutant rats. Alpha-synuclein accumulation in mitochondria of dopaminergic neurons is associated with impaired enzymatic respiratory complex I and IV activity. The behavioral and biochemical lesions progress after 15 days postnatal, and by 30-40 days the animals must be euthanized because of neurological impairment. Based on the obtained results, we propose a pleiotropic pathogenesis that links the Myo5a gene mutation to deficient neuronal development and progressive neurodegeneration. This potential model of a neurodevelopmental disorder with neurodegeneration and motor deficits may provide further insight into molecular motors and their associated proteins responsible for altered neurogenesis and neuronal disease pathogenesis.

Topics: 3,4-Dihydroxyphenylacetic Acid; alpha-Synuclein; Animals; Central Nervous System; Disease Models, Animal; Electron Transport Chain Complex Proteins; Heredodegenerative Disorders, Nervous System; Microscopy, Electron, Transmission; Mutation; Myosin Heavy Chains; Myosin Type V; Phosphorylation; Rats; Rats, Mutant Strains; tau Proteins

Polyunsaturated fatty acids omega-3 (n-3 PUFA), such as docosahexaenoic acid (DHA), have been shown to prevent, and partially reverse, neurotoxin-induced nigrostriatal denervation in animal models of Parkinson's disease (PD). However, the accumulation of α-synuclein (αSyn) in cerebral tissues is equally important to the pathophysiology. To determine whether DHA intake improves various aspects related to synucleinopathy, ninety male mice overexpressing human αSyn under the Thy-1 promoter (Thy1-αSyn) were fed one of three diets (specially formulated control, low n-3 PUFA or high DHA) and compared to non-transgenic C57/BL6 littermate mice exposed to a control diet. Thy1-αSyn mice displayed impaired motor skills, lower dopaminergic neuronal counts within the substantia nigra (-13%) in parallel to decreased levels of the striatal dopamine transporter (DAT) (-24%), as well as reduced NeuN (-41%) and synaptic proteins PSD-95 (-51%), synaptophysin (-80%) and vesicular acetylcholine transporter (VChAT) (-40%) in the cerebral cortex compared to C57/BL6 mice. However, no significant difference in dopamine concentrations was observed by HPLC analysis between Thy1-αSyn and non-transgenic C57/BL6 littermates under the control diet. The most striking finding was a favorable effect of DHA on the survival/longevity of Thy1-αSyn mice (+51% survival rate at 12months of age). However, dietary DHA supplementation did not have a significant effect on other parameters examined in this study, despite increased striatal dopamine concentrations. While human αSyn monomers and oligomers were detected in the cortex of Thy1-αSyn mice, the effects of the diets were limited to a small increase of 42kDa oligomers in insoluble protein fractions upon n-3 PUFA deprivation. Overall, our data indicate that a diet rich in n-3 PUFA has a beneficial effect on the longevity of a murine model of α-synucleinopathy without a major impact on the dopamine system and motor impairments, nor αSyn levels.

Topics: alpha-Synuclein; Animals; Brain; Dietary Supplements; Disease Models, Animal; Docosahexaenoic Acids; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinsonian Disorders

Exposure to traumatic brain injury is a core risk factor that predisposes an individual to sporadic neurodegenerative diseases. We provide evidence that mechanical stress increases brain levels of hallmark proteins associated with neurodegeneration.. Wild-type mice were exposed to multiple regimens of repetitive mild traumatic brain injury, generating a range of combinations of impact energies, frequencies, and durations of exposure. Brain concentrations of amyloid β 1-42 (Aβ. There was a highly significant main effect of impact energy, frequency, and duration of exposure on Aβ. Dose-dependent and cumulative influence of repetitive mild traumatic brain injury-induced mechanical stress may trigger and/or accelerate neurodegeneration by pushing protein concentration over the disease threshold.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Biomechanical Phenomena; Brain; Brain Concussion; Disease Models, Animal; Male; Mice, Inbred BALB C; Peptide Fragments; Random Allocation; Stress, Mechanical; tau Proteins

α-synuclein (αS) is a small protein that self-aggregates into α-helical oligomer species and subsequently into larger insoluble amyloid fibrils that accumulate in intraneuronal inclusions during the development of Parkinson's disease. Toxicity of αS oligomers and fibrils has been long debated and more recent data are suggesting that both species can induce neurodegeneration. However while most of these data are based on differences in structure between oligomer and aggregates, often preassembled in vitro, the in vivo situation might be more complex and subcellular locations where αS species accumulate, rather than their conformation, might contribute to enhanced toxicity. In line with this observation, we have shown that αS oligomers and aggregates are associated with the endoplasmic reticulum/microsomes (ER/M) membrane in vivo and how accumulation of soluble αS oligomers at the ER/M level precedes neuronal degeneration in a mouse model of α-synucleinopathies. In this paper we took a further step, investigating the biochemical and functional features of αS species associated with the ER/M membrane. We found that by comparison with non-microsomal associated αS (P10), the ER/M-associated αS pool is a unique population of oligomers and aggregates with specific biochemical traits such as increased aggregation, N- and C-terminal truncations and phosphorylation at serine 129. Moreover, when administered to murine primary neurons, ER/M-associated αS species isolated from diseased A53T human αS transgenic mice induced neuronal changes in a time- and dose-dependent manner. In fact the addition of small amounts of ER/M-associated αS species from diseased mice to primary cultures induced the formation of beads-like structures or strings of fibrous αS aggregates along the neurites, occasionally covering the entire process or localizing at the soma level. By comparison treatment with P10 fractions from the same diseased mice resulted in the formation of scarce and small puncta only when administered at high amount. Moreover, increasing the amount of P100/M fractions obtained from diseased and, more surprisingly, from presymptomatic mice induced a significant level of neuronal death that was prevented when neurons were treated with ER/M fractions immunodepleted of αS high molecular weight (HMW) species. These data provide the first evidence of the existence of two different populations of αS HMW species in vivo, putting the spotlight on the association to ER/M membrane

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Line, Tumor; Cerebral Cortex; Disease Models, Animal; Endoplasmic Reticulum; Humans; Mice, Transgenic; Microsomes; Molecular Weight; Nerve Degeneration; Neurodegenerative Diseases; Neurons; Primary Cell Culture; Protein Aggregation, Pathological

Genetics and neuropathology strongly link α-synuclein aggregation and neurotoxicity to the pathogenesis of Parkinson's disease and related α-synucleinopathies. Here we describe a new Drosophila model of α-synucleinopathy based on widespread expression of wild-type human α-synuclein, which shows robust neurodegeneration, early-onset locomotor deficits, and abundant α-synuclein aggregation. We use results of forward genetic screening and genetic analysis in our new model to demonstrate that α-synuclein expression promotes reorganization of the actin filament network and consequent mitochondrial dysfunction through altered Drp1 localization. Similar changes are present in a mouse α-synucleinopathy model and in postmortem brain tissue from patients with α-synucleinopathy. Importantly, we provide evidence that the interaction of α-synuclein with spectrin initiates pathological alteration of the actin cytoskeleton and downstream neurotoxicity. These findings suggest new therapeutic approaches for α-synuclein induced neurodegeneration.

Topics: Actin Cytoskeleton; Aged; Aged, 80 and over; alpha-Synuclein; Animals; Cytoskeletal Proteins; Disease Models, Animal; Drosophila melanogaster; Female; GTP-Binding Proteins; Humans; Lewy Body Disease; Male; Middle Aged; Mitochondria; Nerve Degeneration; Spectrin

Sway is a crucial gait characteristic tightly correlated with the risk of falling in patients with Parkinsońs disease (PD). So far, the swaying pattern during locomotion has not been investigated in rodent models using the analysis of dynamic footprint recording obtained from the CatWalk gait recording and analysis system.. We present three methods for describing locomotion sway and apply them to footprint recordings taken from C57BL6/N wild-type mice and two different α-synuclein transgenic PD-relevant mouse models (α-syn. The three proposed methods were successfully applied to the footprint recordings taken from all paws as well as from front/hind-paws separately. Nine resulting sway-related parameters were generated and successfully applied to differentiate between the mouse models under study. Namely, α-synucleinopathic mice revealed higher sway and sway itself was significantly higher in the α-syn. Previous locomotion sway index computation is based on the estimated center of mass position of mice.. The methods presented in this study provide a sway-related gait characterization. Their application is straightforward and may lead to the identification of gait pattern derived biomarkers in rodent models of PD.

Topics: Algorithms; alpha-Synuclein; Animals; Biomechanical Phenomena; Disease Models, Animal; Foot; Fourier Analysis; Gait Analysis; Gait Disorders, Neurologic; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Parkinsonian Disorders; Signal Processing, Computer-Assisted

Parkinson's disease (PD) is a progressive neurodegenerative disorder with behavioral and motor abnormalities. Androst-5-ene-3β, 17β-diol (ADIOL), an estrogen receptor (ER) β agonist, was found to mediate a transrepressive mechanism that selectively modulates the extent of neuroinflammation and, in turn, neurodegeneration. In consensus, ERβ polymorphism was more frequently detected in early-onset PD patients. Thus, in an approach to elucidate the role of ERβ agonists on PD, our study was designed to investigate the possible neuroprotective effect of ADIOL, in three dose levels (0.35, 3.5, 35 mg/kg/day), against rotenone (ROT)-induced PD rat model. Amelioration in striatal dopamine (DA), nuclear factor-kappa B (NF-κB), and the expression of down-stream inflammatory mediators, as well as apoptotic markers were observed in the striatum and substantia nigra (SN) upon pre-treatment with the three doses of ADIOL. Similarly, light microscopy (LM) examination revealed declined degeneration of neurons upon pretreatment with ADIOL. Significant improvement in nigral tyrosine hydroxylase (TH) and reduction of nigral α-synuclein densities were also detected after ADIOL pre-treatment with better results frequently achieved with the middle dose (3.5 mg/kg/day). The middle dose of ADIOL showed behavioral improvement, with elevation in the ATP level, which was emphasized by the improvement in mitochondrial integrity observed upon electron microscopy (EM) examination. In conclusion, the present study confirmed for the first time the ability of ADIOL to protect against neuroinflammation and, in turn, neurodegeneration process and motor dysfunction in PD animal model, which was more obviously observed with the middle dose.

Topics: alpha-Synuclein; Androstenediol; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Estrogen Receptor beta; Inflammation Mediators; Male; Motor Activity; Neurons; Neuroprotective Agents; NF-kappa B; Parkinson Disease; Rats; Rats, Wistar; Rotenone; Substantia Nigra; Tyrosine 3-Monooxygenase

As microglial activation is a key factor in the pathogenesis of Parkinson's disease (PD), drugs that target this process may help to prevent or delay the development of PD. The present study investigated the effects of dl‑3‑n‑butylphthalide (NBP) on microglia in a lipopolysaccharide (LPS)-induced PD mouse model. The mice were randomly divided into a blank control group, LPS control group and NBP + LPS treatment group. Mice in the treatment group were given an intragastric infusion of 120 mg/kg NBP daily for 30 days during the establishment of the PD mouse model. At 4 and 28 weeks post‑treatment, the motor behaviours of the mice in each group were observed using the rotarod test and the open field test. In addition, immunohistochemical staining was performed to determine the levels of activated microglia, tumour necrosis factor‑α and α‑synuclein, and the number of tyrosine hydroxylase (TH)‑positive cells in the substantia nigra. NBP significantly improved dyskinesia, reduced microglial activation, decreased nuclear α‑synuclein deposition and increased the survival of TH‑positive cells in the substantia nigra of LPS‑induced PD model mice. These findings suggested that NBP may exert its therapeutic effect by reducing microglial activation in a mouse model of PD.

Topics: alpha-Synuclein; Animals; Benzofurans; Disease Models, Animal; Dyskinesias; Gene Expression Regulation; Immunohistochemistry; Lipopolysaccharides; Male; Maze Learning; Mice; Mice, Inbred C57BL; Microglia; Motor Activity; Neuroprotective Agents; Parkinson Disease, Secondary; Rotarod Performance Test; Substantia Nigra; Tumor Necrosis Factor-alpha; Tyrosine 3-Monooxygenase

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder characterized by widespread oligodendroglial cytoplasmic inclusions of filamentous α-synuclein, and neuronal loss in autonomic centres, basal ganglia and cerebellar circuits. It has been suggested that primary oligodendroglial α-synucleinopathy may represent a trigger in the pathogenesis of MSA, but the mechanisms underlying selective vulnerability and disease progression are unclear. The post-mortem analysis of MSA brains provides a static final picture of the disease neuropathology, but gives no clear indication on the sequence of pathogenic events in MSA. Therefore, alternative methods are needed to address these issues. We investigated selective vulnerability and disease progression in the transgenic PLP-α-syn mouse model of MSA characterized by targeted oligodendroglial α-synuclein overexpression aiming to provide a neuropathological correlate of motor deterioration. We show progressive motor deficits that emerge at 6 months of age and deteriorate up to 18 months of follow-up. The motor phenotype was associated with dopaminergic cell loss in the substantia nigra pars compacta at 6 months, followed by loss of striatal dopaminergic terminals and DARPP32-positive medium sized projection neurons at 12 months. Olivopontocerebellar motor loops remained spared in the PLP-α-syn model of MSA. These findings replicate progressive striatonigral degeneration underlying Parkinson-variant MSA. The initiation of the degenerative process was linked to an increase of soluble oligomeric α-synuclein species between 2 and 6 months. Early region-specific α-synuclein-associated activation profile of microglia was found in MSA substantia nigra. The role of abnormal neuroinflammatory signalling in disease progression was further supported by increased levels of CD68, CCL3, CCL5 and M-CSF with a peak in aged PLP-α-syn mice. In summary, transgenic PLP-α-syn mice show a distinctive oligodendroglial α-synucleinopathy that is associated with progressive striatonigral degeneration linked to abnormal neuroinflammatory response. The model provides a relevant tool for preclinical therapeutic target discovery for human Parkinson-variant MSA.

Topics: Age Factors; alpha-Synuclein; Analysis of Variance; Animals; Antigens, CD; Calcium-Binding Proteins; Disease Models, Animal; Gene Expression Regulation; Humans; Mice; Mice, Transgenic; Microfilament Proteins; Microglia; Microscopy, Confocal; Movement Disorders; Multiple System Atrophy; Muscle Strength; Myelin Proteolipid Protein; Nerve Tissue Proteins; Postural Balance; Sensation Disorders; Striatonigral Degeneration

Alpha-synuclein plays a key role in the pathogenesis of Parkinson's disease (PD). A robust transgenic mouse model has been generated that overexpresses the mutant human A53T alpha-synuclein under the mouse prion protein gene promoter; these mice develop age-dependent motor deficits. Recently, compared to wild-type (WT) littermates, A53T alpha-synuclein mice were reported to display non-motor symptom deficits, e.g., anxiety-like and depressive-like behaviors, odor discrimination and detection impairments, and gastrointestinal dysfunction, at 6 months of age or older. However, the differences between heterozygous and homozygous mice in terms of non-motor symptoms and whether the genomic DNA levels of alpha-synuclein correlate with the symptoms have not yet been elucidated. In the present work, we used littermate WT and heterozygous and homozygous A53T mice that were characterized by a modified genotyping protocol and observed a unilateral decline in the dopamine transporter (DAT) distribution from 3 months to 12 months of age in homozygous mice. We evaluated non-motor symptoms by measuring colon motility, anxiety-like and depressive-like behaviors, and motor coordination. The results showed that homozygous A53T mice exhibited earlier abnormal non-motor symptoms compared to their heterozygous littermates. The severity of impaired colon motility as well as anxiety-like and depressive-like behaviors were correlated with the genomic DNA levels of A53T mutant alpha-synuclein. More noticeable, motor coordination aberrances were also observed in homozygous A53T mice. This study provides direct evidence that the genomic DNA levels of mutant alpha-synuclein correlate with non-motor symptoms in an A53T mouse model, indicating that the genomic DNA levels of mutant alpha-synuclein should be tightly manipulated in PD model studies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; DNA; Genomics; Humans; Mice; Mice, Transgenic; Mutation; Parkinson Disease

Circular RNAs (circRNAs) are peculiar non-coding RNA molecules which are known to be present across taxa. Considering the body of evidence that establishes critical functions of non-coding RNA molecules, we endeavored to study circRNAs in the context of Parkinson's disease (PD). Employing transgenic C. elegans model of PD, we used RNase R-mediated cleavage of linear RNA followed by divergent primer-based amplifications towards identifying circzip-2, a novel circRNA molecule. We went on to sequence circzip-2 which is synthesized from functionally important gene zip-2. Studying RNAi-induced knockdown conditions of zip-2, we observed a reduced aggregation of α-synuclein protein along with an enhanced lifespan of the worms. We further carried out transcriptome analysis of zip-2 silenced worms, which suggested that zip-2 might be functioning via Daf-16 pathway. Further interaction studies revealed that circzip-2 possibly sponges microRNA molecule miR-60 towards asserting an important role in various processes associated with PD.

Topics: Acetylcholine; Acetylcholinesterase; alpha-Synuclein; Animals; Basic-Leucine Zipper Transcription Factors; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Down-Regulation; Gene Amplification; Gene Knockdown Techniques; Genes, Helminth; Longevity; Parkinson Disease; Reactive Oxygen Species; Reproducibility of Results; RNA; RNA, Circular; Up-Regulation

Prolyl oligopeptidase (PREP) inhibition by small-molecule inhibitors can reduce alpha-synuclein (aSyn) aggregation, a key player in Parkinson's disease pathology. However, the significance of PREP protein for aSyn aggregation and toxicity is not known. We studied this in vivo by using PREP knock-out mice with viral vector injections of aSyn and PREP. Animal behavior was studied by locomotor activity and cylinder tests, microdialysis and HPLC were used to analyze dopamine levels, and different aSyn forms and loss of dopaminergic neurons were studied by immunostainings. Additionally, PREP knock-out cells were used to characterize the impact of PREP and aSyn on autophagy, proteasomal system and aSyn secretion. PREP knock-out animals were nonresponsive to aSyn-induced unilateral toxicity but combination of PREP and aSyn injections increased aSyn toxicity. Phosphorylated p129, proteinase K resistant aSyn levels and tyrosine hydroxylase positive cells were decreased in aSyn and PREP injected knock-out animals. These changes were accompanied by altered dopamine metabolite levels. PREP knock-out cells showed reduced response to aSyn, while cells were restored to wild-type cell levels after PREP overexpression. Taken together, our data suggests that PREP can enhance aSyn toxicity in vivo.

Topics: alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Chromatography, High Pressure Liquid; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Immunohistochemistry; Locomotion; Mice; Mice, Knockout; Parkinson Disease; Prolyl Oligopeptidases; Proteasome Endopeptidase Complex; Serine Endopeptidases

Amyloid-β peptide (Aβ), paired helical filament-tau (PHF-tau), and α-synuclein are in the focus of neuroscience research because they aggregate in brains of patients with Alzheimer's and Parkinson's diseases. For this purpose, transgenic mouse models were used containing the human genes for AβPP/presenilin/tau or α-synuclein with the most frequent mutations. This is not ideal because most patients develop sporadic forms of the diseases with no causative single gene defect and furthermore the aggregation of human proteins in man is not necessarily the same in rodents. We hypothesized that for such cases the aged mouse could be an alternative model and analyzed the distribution of endogenous Aβ, PHF-tau, and α-synuclein in mouse brains at different ages. Whereas Aβ was below detectable levels at birth, it was present at high levels in the 15-month-old mouse. Aβ was found in the cytosol and lysosomes of neurons of the temporal cortex, cingulate area, pons, and cerebellum as well as extracellularly in the periventricular zone. Contrary to Aβ, mouse brain was devoid of PHF-tau-positive neurofibrillary tangles. α-Synuclein was detectable in the newborn mouse with highest levels in the marginal zone of the lateral cortex and average levels in the hippocampus, pons, and cerebellum. Brain-area specific differences in the α-synuclein level persisted up to 15 months of age, but increased 3-fold in all areas over time. α-Synuclein resided in the neuropil, but not in intracellular aggregates even in the aged mouse. We suggest the aged mouse as a model to study Aβ plaque formation.

Topics: Age Factors; Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurofibrillary Tangles; Neurons; Plaque, Amyloid; tau Proteins

Increased expression of α-synuclein can initiate its long-distance brain transfer, representing a potential mechanism for pathology spreading in age-related synucleinopathies, such as Parkinson's disease. In this study, the effects of overexpression-induced α-synuclein transfer were assessed over a 1-year period after injection of viral vectors carrying human α-synuclein DNA into the rat vagus nerve. This treatment causes targeted overexpression within neurons in the dorsal medulla oblongata and subsequent diffusion of the exogenous protein toward more rostral brain regions. Protein advancement and accumulation in pontine, midbrain, and forebrain areas were contingent upon continuous overexpression, because death of transduced medullary neurons resulted in cessation of spreading. Lack of sustained spreading did not prevent the development of long-lasting pathological changes. Particularly remarkable were findings in the locus coeruleus, a pontine nucleus with direct connections to the dorsal medulla oblongata and greatly affected by overexpression-induced transfer in this model. Data revealed progressive degeneration of catecholaminergic neurons that proceeded long beyond the time of spreading cessation. Neuronal pathology in the locus coeruleus was accompanied by pronounced microglial activation and, at later times, astrocytosis. Interestingly, microglial activation was also featured in another region reached by α-synuclein transfer, the central amygdala, even in the absence of frank neurodegeneration. Thus, overexpression-induced spreading, even if temporary, causes long-lasting pathological consequences in brain regions distant from the site of overexpression but anatomically connected to it. Neurodegeneration may be a consequence of severe protein burden, whereas even a milder α-synuclein accumulation in tissues affected by protein transfer could induce sustained microglial activation.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Male; Parkinson Disease; Rats

Mutations in LRRK2 are known to be the most common genetic cause of sporadic and familial Parkinson's disease (PD). Multiple lines of LRRK2 transgenic or knockin mice have been developed, yet none exhibit substantial dopamine (DA)-neuron degeneration. Here we develop human tyrosine hydroxylase (TH) promoter-controlled tetracycline-sensitive LRRK2 G2019S (GS) and LRRK2 G2019S kinase-dead (GS/DA) transgenic mice and show that LRRK2 GS expression leads to an age- and kinase-dependent cell-autonomous neurodegeneration of DA and norepinephrine (NE) neurons. Accompanying the loss of DA neurons are DA-dependent behavioral deficits and α-synuclein pathology that are also LRRK2 GS kinase-dependent. Transmission EM reveals that that there is an LRRK2 GS kinase-dependent significant reduction in synaptic vesicle number and a greater abundance of clathrin-coated vesicles in DA neurons. These transgenic mice indicate that LRRK2-induced DA and NE neurodegeneration is kinase-dependent and can occur in a cell-autonomous manner. Moreover, these mice provide a substantial advance in animal model development for LRRK2-associated PD and an important platform to investigate molecular mechanisms for how DA neurons degenerate as a result of expression of mutant LRRK2.

Topics: Age Factors; alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Mice; Mice, Transgenic; Motor Activity; Mutation; Neurodegenerative Diseases; Norepinephrine

Parkinson's disease (PD) is the second most common neurodegenerative disease, affecting approximately one-percent of the population over the age of sixty. Although many animal models have been developed to study this disease, each model presents its own advantages and caveats. A unique model has arisen to study the role of alpha-synuclein (aSyn) in the pathogenesis of PD. This model involves the conversion of recombinant monomeric aSyn protein to a fibrillar form-the aSyn pre-formed fibril (aSyn PFF)-which is then injected into the brain or introduced to the media in culture. Although many groups have successfully adopted and replicated the aSyn PFF model, issues with generating consistent pathology have been reported by investigators. To improve the replicability of this model and diminish these issues, The Michael J. Fox Foundation for Parkinson's Research (MJFF) has enlisted the help of field leaders who performed key experiments to establish the aSyn PFF model to provide the research community with guidelines and practical tips for improving the robustness and success of this model. Specifically, we identify key pitfalls and suggestions for avoiding these mistakes as they relate to generating the aSyn PFFs from monomeric protein, validating the formation of pathogenic aSyn PFFs, and using the aSyn PFFs in vivo or in vitro to model PD. With this additional information, adoption and use of the aSyn PFF model should present fewer challenges, resulting in a robust and widely available model of PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Parkinson Disease; Rodentia

Loss of function mutations in the gene ATP13A2 are associated with Kufor-Rakeb Syndrome and Neuronal Ceroid Lipofuscinosis, the former designated as an inherited form of Parkinson's disease (PD). The function of ATP13A2 is unclear but in vitro studies indicate it is a lysosomal protein and may interact with the presynaptic protein alpha-synuclein (aSyn) and certain heavy metals. Accumulation of aSyn is a major component of lewy bodies, the pathological hallmark of PD. Atp13a2-deficient (13a2) mice develop age-dependent sensorimotor deficits, and accumulation of insoluble aSyn in the brain. To better understand the interaction between ATP13A2 and aSyn, double mutant mice with loss of Atp13a2 function combined with overexpression of human wildtype aSyn were generated. Female and male wildtype (WT), 13a2, aSyn, and 13a2-aSyn mice were tested on a battery of sensorimotor tests including adhesive removal, challenging beam traversal, spontaneous activity, gait, locomotor activity, and nest-building at 2, 4, and 6 months of age. Double mutant mice showed an earlier onset and accelerated alterations in sensorimotor function that were age, sex and test-dependent. Female 13a2-aSyn mice showed early and progressive dysfunction on the beam and in locomotor activity. In males, 13a2-aSyn mice showed more severe impairments in spontaneous activity and adhesive removal. Sex differences were also observed in aSyn and 13a2-aSyn mice on the beam, cylinder, and adhesive removal tests. In other tasks, double mutant mice displayed deficits similar to aSyn mice. These results indicate loss of Atp13a2 function exacerbates the sensorimotor phenotype in aSyn mice in an age and sex-dependent manner.

Topics: Adenosine Triphosphatases; alpha-Synuclein; Animals; Body Temperature; Body Weight; Disease Models, Animal; Female; Gait Disorders, Neurologic; Humans; Male; Membrane Proteins; Mice, Inbred C57BL; Mice, Transgenic; Motor Skills; Phenotype; Proton-Translocating ATPases; Severity of Illness Index; Sex Characteristics

Parkinson's disease (PD) is no longer primarily classified as a motor disorder due to increasing recognition of the impact on patients of several nonmotor PD symptoms, including cognitive dysfunction. These nonmotor symptoms are highly prevalent and greatly affect the quality of life of patients with PD, and so, therapeutic interventions to alleviate these symptoms are urgently needed. The aim of this study was to investigate the potential neuroprotective effects of voluntary running on cognitive dysfunction in an adeno-associated virus-α-synuclein rat model of PD. Bilateral intranigral administration of adeno-associated virus-α-synuclein was found to induce motor dysfunction and a significant loss of nigral dopaminergic neurons, neither of which were rescued by voluntary running. Overexpression of α-synuclein also resulted in significant impairment on hippocampal neurogenesis-dependent pattern separation, a cognitive task; this was rescued by voluntary running. This was substantiated by an effect of running on neurogenesis levels in the dorsal dentate gyrus, suggesting that the functional effects of running on pattern separation were mediated via increased neurogenesis.

Topics: alpha-Synuclein; Animals; Cognitive Dysfunction; Dependovirus; Disease Models, Animal; Hippocampus; Male; Neurogenesis; Parkinson Disease; Rats, Sprague-Dawley; Running

The accumulation of aggregate-prone proteins is a major representative of many neurological disorders, including Parkinson's disease (PD) wherein the cellular clearance mechanisms, such as the ubiquitin-proteasome and autophagy pathways are impaired. PD, known to be associated with multiple genetic and environmental factors, is characterized by the aggregation of α-synuclein protein and loss of dopaminergic neurons in midbrain. This disease is also associated with other cardiovascular ailments. Herein, we report our findings from studies on the effect of hyper and hypo-osmotic induced toxicity representing hyper and hypotensive condition as an extrinsic epigenetic factor towards modulation of Parkinsonism, using a genetic model Caenorhabditis elegans (C. elegans). Our studies showed that osmotic toxicity had an adverse effect on α-synuclein aggregation, autophagic puncta, lipid content and oxidative stress. Further, we figure that reduced autophagic activity may cause the inefficient clearance of α-synuclein aggregates in osmotic stress toxicity, thereby promoting α-synuclein deposition. Pharmacological induction of autophagy by spermidine proved to be a useful mechanism for protecting cells against the toxic effects of these proteins in such stress conditions. Our studies provide evidence that autophagy is required for the removal of aggregated proteins in these conditions. Studying specific autophagy pathways, we observe that the osmotic stress induced toxicity was largely associated with atg-7 and lgg-1 dependent autophagy pathway, brought together by involvement of mTOR pathway. This represents a unifying pathway to disease in hyper- and hypo-osmotic conditions within PD model of C. elegans.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopaminergic Neurons; Humans; Lipid Metabolism; Microtubule-Associated Proteins; Osmotic Pressure; Oxidative Stress; Parkinson Disease; Spermidine; Ubiquitin

The present study was designed to ascertain the role of naringenin (NGN), a citrus fruit flavanone, against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced α-synuclein (SYN) pathology and neuroinflammation in a mouse model. NGN was administered to C57BL/6J mice once a day for 5 consecutive days prior to the MPTP intoxication. On day 5, 40-50 min after the NGN or vehicle administration, MPTP was injected in two divided doses (2× 40 mg/kg, i.p. at 16 h apart). The animals were observed for motor functions 48 h after the first MPTP injection. The animals were then euthanized, the brains collected to analyze SYN pathology, cytokines, and oxidative stress levels in the substantia nigra region. The NGN significantly downregulated SYN and upregulated dopamine transporter (DAT) and tyrosine hydroxylase (TH) protein expressions. It also downregulated tumor necrosis factor-α (TNFα) and interleukin 1β (IL1β) mRNA expressions and improved superoxide dismutase levels. It also reduced glutathione levels when compared to vehicle-treated PD animals. The upregulation of TH corroborates to an increase in dopamine, DOPAC, and homovanillic acid turnover and motor functions with NGN treatment. To summarize, NGN, a dietary flavone, has the potential to counteract MPTP-induced dopaminergic degeneration by regulating SYN pathology, neuroinflammation, and oxidative stress. This warrants the investigation of NGN's potential effects in a genetic model of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Anti-Inflammatory Agents; Cytokines; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; Encephalitis; Flavanones; Gene Expression Regulation; Glutathione; Locomotion; Male; Mice; Mice, Inbred C57BL; Muscle Strength; Neurotransmitter Agents; Nitric Oxide; Oxidative Stress; Parkinson Disease; RNA, Messenger; Tyrosine 3-Monooxygenase

We probed the role of alpha-synuclein (α-syn) in modulating sorting nexin 3 (Snx3)-retromer-mediated recycling of iron transporters in Saccharomyces cerevisiae and Caenorhabditis elegans. In yeast, the membrane-bound heterodimer Fet3/Ftr1 is the high affinity iron importer. Fet3 is a membrane-bound multicopper ferroxidase, whose ferroxidase domain is orthologous to human ceruloplasmin (Cp), that oxidizes external Fe+2 to Fe+3; the Fe+3 ions then channel through the Ftr1 permease into the cell. When the concentration of external iron is low (<1 µM), Fet3/Ftr1 is maintained on the plasma membrane by retrograde endocytic-recycling; whereas, when the concentration of external iron is high (>10 µM), Fet3/Ftr1 is endocytosed and shunted to the vacuole for degradation. We discovered that α-syn expression phenocopies the high iron condition: under the low iron condition (<1 µM), α-syn inhibits Snx3-retromer-mediated recycling of Fet3/Ftr1 and instead shunts Fet3/Ftr1 into the multivesicular body pathway to the vacuole. α-Syn inhibits recycling by blocking the association of Snx3-mCherry molecules with endocytic vesicles, possibly by interfering with the binding of Snx3 to phosphatidylinositol-3-monophosphate. In C. elegans, transgenic worms expressing α-syn exhibit an age-dependent degeneration of dopaminergic neurons that is partially rescued by the iron chelator desferoxamine. This implies that α-syn-expressing dopaminergic neurons are susceptible to changes in iron neurotoxicity with age, whereby excess iron enhances α-syn-induced neurodegeneration. In vivo genetic analysis indicates that α-syn dysregulates iron homeostasis in worm dopaminergic neurons, possibly by inhibiting SNX-3-mediated recycling of a membrane-bound ortholog of Cp (F21D5.3), the iron exporter ferroportin (FPN1.1), or both.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Carrier Proteins; Ceruloplasmin; Disease Models, Animal; Endocytosis; Iron; Membrane Transport Proteins; Parkinson Disease; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins

Parkinson's disease manifests as a progressive movement disorder with underlying degeneration of dopaminergic neurons in the substantia nigra, consequent depletion of dopamine levels, and the accumulation of Lewy bodies in the brain. Because α-synuclein (α-Syn) protein is the major component of Lewy bodies, mouse models expressing wild-type or mutant SNCA/α-Syn genes provide a useful tool to investigate canonical characteristics of the disease. We evaluated a mouse model (denoted M20) that expresses human wild-type SNCA gene. The M20 mice showed abnormal locomotor behavior and reduced species-specific home cage activity. However, the direction of behavioral changes was task specific. In comparison with their control littermates, the M20 mice exhibited shorter grip endurance, and longer times to traverse elevated beams, but they descended the vertical pole faster and stayed longer on the accelerated rod than the control mice. The M20 mice were also impaired in burrowing and nest building activities. These results indicate a possible role of α-Syn in motor coordination and the motivation to perform species-specific behaviors in the presymptomatic model of synucleinopathy.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Female; Gene Expression; Homing Behavior; Humans; Lewy Bodies; Locomotion; Male; Mice, Transgenic; Mutation; Parkinson Disease; Psychomotor Performance

Parkinson's disease (PD) is a degenerative disorder of the central nervous system mainly affecting the motor system. Presently, there is no effective and safe drug to treat patients with PD. Ginkgo biloba extract (GBE), obtained from leaves of the Ginkgo biloba tree, is a complex mixture of ingredients primarily containing two active components: flavonoids and terpenoids. In this study, we investigated the effects of GBE on A53T α-synuclein transgenic mice, a PD model that has better simulated the progression of PD patients than other models such as the 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induced PD model.. Fifty α-synuclein A53T transgenic mice were fed and treated with GBE, and locomotor activity was detected by pole test, forced swim test, and wire-hang test. The expression of tyrosine hydroxylase and dopamine transporters was detected using immunohistochemistry. Superoxide dismutase activity, glutathione peroxidase activity, and malondialdehyde expression were detected using an assay kit.. Our results show that GBE treatment improved locomotor activity and that superoxide dismutase and glutathione peroxidase inhibited the expression of methane dicarboxylic aldehyde and recovered the expression of tyrosine hydroxylase and dopamine transporters.. The GBE treatment improved locomotor activity and inhibited the development of PD in the A53T α-synuclein transgenic mice, which may be partly responsible for decreased oxidative damage and maintain the normal dopamine homeostasis.

Topics: Alanine; alpha-Synuclein; Animals; Antiparkinson Agents; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; Dose-Response Relationship, Drug; Ginkgo biloba; Glutathione; Glutathione Peroxidase; Locomotion; Malondialdehyde; Mice; Mice, Transgenic; Muscle Strength; Mutation; Parkinson Disease; Plant Extracts; Superoxide Dismutase; Swimming; Threonine

Recombinant adeno-associated virus (AAV) vectors are a popular genetic approach in neuroscience because they confer such efficient transgene expression in the brain and spinal cord. A number of studies have used AAV to express pathological disease-related proteins in the dopaminergic neurons of the substantia nigra in situ ( e.g., α-synuclein to model aspects of Parkinson's disease). The neuropathology and neurodegeneration of Parkinson's disease occur in a circumscribed pattern in the brain, and one of the most important goals of any gene transfer study is accurate, pinpoint targeting. By combining Cre recombinase-dependent AAVs in Cre-driver rats in which Cre is expressed only in the tyrosine hydroxylase neurons, we have achieved more highly targeted expression of several disease-relevant neuropathological proteins in the substantia nigra pars compacta than using constitutive expression AAV vectors. Alpha-synuclein, tau, transactive response DNA-binding protein of 43 kDa, or the control fluorescent protein yellow fluorescent protein was individually expressed to induce highly targeted, dopaminergic neuron-specific neurodegeneration models. The refined targeting foreshadows a next-generation disease modeling system for expressing neurodegenerative disease-related proteins in a disease-relevant manner. We foresee specific utilities of this in vivo AAV vector targeting of pathological proteins to a well-defined and well-demarcated cell population.-Grames, M. S., Dayton, R. D., Jackson, K. L., Richard, A. D., Lu, X., Klein, R. L. Cre-dependent AAV vectors for highly targeted expression of disease-related proteins and neurodegeneration in the substantia nigra.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Female; Genetic Vectors; Integrases; Neurodegenerative Diseases; Rats; Substantia Nigra

Intracellular accumulation of alpha-synuclein (α-syn) is a key pathological process evident in Lewy body dementias (LBDs), including Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB). LBD results in marked cognitive impairments and changes in cortical networks. To assess the impact of abnormal α-syn expression on cortical network oscillations relevant to cognitive function, we studied changes in fast beta/gamma network oscillations in the hippocampus in a mouse line that over-expresses human mutant α-syn (A30P). We found an age-dependent reduction in the power of the gamma (20-80 Hz) frequency oscillations in slices taken from mice aged 9-16 months (9+A30P), that was not present in either young 2-6 months old (2+A30P) mice, or in control mice at either age. The mitochondrial blockers potassium cyanide and rotenone both reduced network oscillations in a concentration-dependent manner in aged A30P mice and aged control mice but slices from A30P mice showed a greater reduction in the oscillations. Histochemical analysis showed an age-dependent reduction in cytochrome c oxidase (COX) activity, suggesting a mitochondrial dysfunction in the 9+A30P group. A deficit in COX IV expression was confirmed by immunohistochemistry. Overall, our data demonstrate an age-dependent impairment in mitochondrial function and gamma frequency activity associated with the abnormal expression of α-syn. These findings provide mechanistic insights into the consequences of over-expression of α-syn which might contribute to cognitive decline.

Topics: Aging; alpha-Synuclein; Animals; Disease Models, Animal; Female; Gamma Rhythm; Hippocampus; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Mitochondria; Mitochondrial Diseases; Proteostasis Deficiencies; Tissue Culture Techniques

Intraneuronal inclusions of alpha-synuclein are commonly found in the brain of patients with Parkinson's disease and other α-synucleinopathies. The correlation between alpha-synuclein pathology and symptoms has been studied in various animal models. In (Thy-1)-h[A30P] alpha-synuclein transgenic mice, behavioral and motor abnormalities were reported from 12 and 15 months, respectively. The aim of this study was to investigate whether these mice also display symptoms at earlier time points.. We analyzed gait deficits, locomotion, and behavioral profiles in (Thy-1)-h[A30P] alpha-synuclein and control mice at 2, 8, and 11 months of age. In addition, inflammatory markers, levels of alpha-synuclein oligomers, and tyrosine hydroxylase reactivity were studied.. Already at 2 months of age, transgenic mice displayed fine motor impairments in the challenging beam test that progressively increased up to 11 months of age. At 8 months, transgenic mice showed a decreased general activity with increased risk-taking behavior in the multivariate concentric square field test. Neuropathological analyses of 8- and 11-month-old mice revealed accumulation of oligomeric alpha-synuclein in neuronal cell bodies. In addition, a decreased presence of tyrosine hydroxylase suggests a dysregulation of the dopaminergic system in the transgenic mice, which in turn may explain some of the motor impairments observed in this mouse model.. Taken together, our results show that the (Thy-1)-h[A30P] alpha-synuclein transgenic mouse model displays early Parkinson's disease-related symptoms with a concomitant downregulation of the dopaminergic system. Thus, this should be an appropriate model to study early phenotypes of alpha-synucleinopathies.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Female; Male; Mice; Mice, Transgenic; Motor Activity; Motor Disorders; Parkinson Disease

Glucocerebrosidase gene (GBA) mutations are the most common genetic contributor to Parkinson's disease (PD) and are associated with decreased glucocerebrosidase (GCase) enzymatic activity in PD. PD patients without GBA mutations also exhibit lower levels of GCase activity in the central nervous system suggesting a potential contribution of the enzyme activity in disease pathogenesis, possibly by alteration of lysosomal function. α-synuclein (ASYN), a protein with a central role in PD pathogenesis, has been shown to be secreted partly in association with exosomes. It is possible that a dysfunction of the endocytic pathway through GCase may result in altered exosome release of ASYN. The aim of this study was to examine whether manipulating GCase activity in vivo and in vitro could affect ASYN accumulation and secretion. GCase overexpression in vitro resulted in a significant decrease of exosome secretion. Chronic inhibition of GCase activity in vivo, by administration of the covalent inhibitor conduritol-B epoxide in A53T-synuclein alpha gene Tg mice significantly elevated intracellular oligomeric ASYN species. Importantly, GCase inhibition, induced a profound increase in the number of brain exosomes released, as well as exosome-associated ASYN oligomers. Finally, virus-mediated expression of mutant GBA in the mouse striatum increased ASYN secretion in the same region. Together, these results provide for the first time evidence that a decrease of GCase or overexpression of mutant GCase in a chronic in vivo setting can affect ASYN secretion. Such effects may mediate enhanced propagation of ASYN, driving pathology in GBA-associated PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Exosomes; Glucosylceramidase; Humans; Inositol; Lysosomes; Mice; Mutation; Parkinson Disease

Microglia-mediated neuroinflammation is implicated in multiple neurodegenerative disorders, including Parkinson's disease (PD). Hence, the modulatioein of sustained microglial activation may have therapeutic potential. This study is designed to test the neuroprotective efficacy of taurine, a major intracellular free β-amino acid in mammalian tissues, by using paraquat and maneb-induced PD model. Results showed that mice intoxicated with paraquat and maneb displayed progressive dopaminergic neurodegeneration and motor deficits, which was significantly ameliorated by taurine. Taurine also attenuated the aggregation of α-synuclein in paraquat and maneb-intoxicated mice. Mechanistically, taurine suppressed paraquat and maneb-induced microglial activation. Moreover, depletion of microglia abrogated the dopaminergic neuroprotective effects of taurine, revealing the role of microglial activation in taurine-afforded neuroprotection. Subsequently, we found that taurine suppressed paraquat and maneb-induced microglial M1 polarization and gene expression levels of proinflammatory factors. Furthermore, taurine was shown to be able to inhibit the activation of NADPH oxidase (NOX2) by interfering with membrane translocation of cytosolic subunit, p47

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Gait; Gene Expression; Male; Maneb; Mice; Mice, Inbred C57BL; Microglia; NADPH Oxidase 2; NADPH Oxidases; Neuroprotective Agents; NF-kappa B; Paraquat; Parkinson Disease, Secondary; Signal Transduction; Taurine

Parkinson's disease (PD) is a chronically progressive neurodegenerative disease, with its main pathological hallmarks being a dramatic loss of dopaminergic neurons predominantly in the Substantia Nigra (SN), and the formations of intracytoplasmic Lewy bodies and dystrophic neurites. Alpha-synuclein (α-syn), widely recognized as the most prominent element of the Lewy body, is one of the representative hallmarks in PD. However, the mechanisms behind the increased α-syn expression and aggregation have not yet been clarified. To examine what causes α-syn expression to increase, we analyzed the pattern of gene expression in the SN of mice intoxicated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), where down-regulation of dopaminergic cells occurred. We identified serum- and glucocorticoid-dependent kinase 1 (SGK1) as one of the genes that is evidently downregulated in chronic MPTP-intoxication. The results of Western blot analyses showed that, together with the down-regulation of dopaminergic cells, the decrease in SGK1 expression increased α-syn expression in the SN in a chronic MPTP-induced Parkinsonism mouse. For an examination of the expression correlation between SGK1 and α-syn, SH-5YSY cells were knocked down with SGK1 siRNA then, the downregulation of dopaminergic cells and the increase in the expression of α-syn were observed. These results suggest that decreased expression of SGK1 may play a critical role in increasing the expression of α-syn, which is related with dopaminergic cell death in the SN of chronic MPTP-induced Parkinsonism mice and in SH-SY5Y cells.

Topics: alpha-Synuclein; Animals; Cell Count; Cell Line; Chronic Disease; Disease Models, Animal; Dopaminergic Neurons; Down-Regulation; Humans; Immediate-Early Proteins; Male; Mice; Mice, Inbred C57BL; MPTP Poisoning; Parkinson Disease, Secondary; Protein Serine-Threonine Kinases; Substantia Nigra

α-Synuclein (α-syn) is a major component of Lewy bodies found in synucleinopathies including Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB). Under the pathological conditions, α-syn tends to generate a diverse form of aggregates showing toxicity to neuronal cells and able to transmit across cells. However, mechanisms by which α-syn aggregates affect cytotoxicity in neurons have not been fully elucidated. Here we report that α-syn aggregates preferentially sequester specific synaptic proteins such as vesicle-associated membrane protein 2 (VAMP2) and synaptosomal-associated protein 25 (SNAP25) through direct binding which is resistant to SDS. The sequestration effect of α-syn aggregates was shown in a cell-free system, cultured primary neurons, and PD mouse model. Furthermore, we identified a specific blocking peptide derived from VAMP2 which partially inhibited the sequestration by α-syn aggregates and contributed to reduced neurotoxicity. These results provide a mechanism of neurotoxicity mediated by α-syn aggregates and suggest that the blocking peptide interfering with the pathological role of α-syn aggregates could be useful for designing a potential therapeutic drug for the treatment of PD.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Cell Survival; Cells, Cultured; Disease Models, Animal; Escherichia coli; Humans; Mice, Inbred C3H; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Neurons; Neuroprotective Agents; Parkinson Disease; Peptides; Protein Aggregation, Pathological; Protein Binding; Rats, Sprague-Dawley; Recombinant Proteins; Vesicle-Associated Membrane Protein 2

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the degeneration of dopaminergic neurons of the substantia nigra and the accumulation of protein aggregates, called Lewy bodies, where the most abundant is alpha-synuclein (α-SYN). Mutations of the gene that codes for α-SYN (SNCA), such as the A53T mutation, and duplications of the gene generate cases of PD with autosomal dominant inheritance. As a result of the association of inflammation with the neurodegeneration of PD, we analyzed whether overexpression of wild-type α-SYN (α-SYN

Topics: alpha-Synuclein; Animals; Chemokine CX3CL1; Disease Models, Animal; Dopaminergic Neurons; Mice, Knockout; Microglia; Neurodegenerative Diseases; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is a common neurodegenerative disease associated with the progressive loss of dopaminergic neurons in the substantia nigra. Proteinaceous depositions of alpha-synuclein (α-syn) and its mutations, A30P and A53T, are one important characteristic of PD. However, little is known about their aggregation and degradation mechanisms. Dendritic cell factor 1 (DCF1) is a membrane protein that plays important roles in nerve development in mouse. In this study, we aimed to show that DCF1 overexpression in a PD Drosophila model significantly ameliorates impaired locomotor behavior in third instar larvae and normalizes neuromuscular junction growth. Furthermore, climbing ability also significantly increased in adult PD Drosophila. More importantly, the lifespan dramatically extended by an average of approximately 23%, and surprisingly, DCF1 could prevent α-syn-induced dopaminergic neuron loss by aggregating α-syn in the dorsomedial region of Drosophila. Mechanistically, we confirmed that DCF1 could degrade α-syn both in vivo and in vitro. Our findings revealed an important role of DCF1 in PD process and may provide new potential strategies for developing drugs to treat neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drosophila; Gene Expression; HEK293 Cells; Humans; Membrane Proteins; Motor Activity; Mutation; Nerve Tissue Proteins; Neuromuscular Junction; Parkinson Disease; Proteolysis

Current pharmacological management of Parkinson disease (PD) does not provide for disease modification, but addresses only symptomatic features. Here, we explore a new approach to neuroprotection based on the use of 2-pentadecyl-2-oxazoline (PEA-OXA), the oxazoline derivative of the fatty acid amide signaling molecule palmitoylethanolamide (PEA), in an experimental model of PD. Daily oral treatment with PEA-OXA (10 mg/kg) significantly reduced behavioral impairments and neuronal cell degeneration of the dopaminergic tract induced by four intraperitoneal injections of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on 8-week-old male C57 mice. Moreover, PEA-OXA treatment prevented dopamine depletion, increased tyrosine hydroxylase and dopamine transporter activities, and decreased α-synuclein aggregation in neurons. PEA-OXA treatment also diminished nuclear factor-κB traslocation, cyclooxygenase-2, and inducible nitric oxide synthase expression and through upregulation of the nuclear factor E2-related factor 2 pathway, induced activation of Mn-superoxide dismutase and heme oxygenase-1. Further, PEA-OXA modulated microglia and astrocyte activation and preserved microtubule-associated protein-2 alterations. In conclusion, pharmacological activation of nuclear factor E2-related factor 2 pathways with PEA-OXA may be effective in the future therapy of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Astrocytes; Behavior, Animal; Cyclooxygenase 2; Cytokines; Disease Models, Animal; DNA Damage; Dopamine Plasma Membrane Transport Proteins; Inflammation; Mice, Inbred C57BL; Microglia; NF-E2-Related Factor 2; Nitric Oxide Synthase Type II; Nitrosative Stress; Oxazoles; Oxidative Stress; Parkinson Disease; Poly Adenosine Diphosphate Ribose; Transcription Factor RelA; Tyrosine; Tyrosine 3-Monooxygenase

Soluble aggregates of α-synuclein, so-called oligomers, are hypothesized to act as neurotoxic species in Parkinson's disease, Lewy body dementia and multiple systems atrophy, but specific tools to detect these aggregated species are only slowly appearing. We have developed an α-synuclein oligomer ELISA that allows us to detect and compare α-synuclein oligomer levels in different in vivo and in vitro experiments. The ELISA is based on commercially available antibodies and the epitope of the capture antibody MJF14-6-4-2 is folding- and aggregate-dependent and not present on monomers.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Epitopes; Male; Mice; Mice, Transgenic; Parkinson Disease; Protein Aggregates

Parkinson's disease (PD) is characterized as a chronic and progressive neurodegenerative disorder, and the deposition of specific protein aggregates of α-synuclein, termed Lewy bodies, is evident in multiple brain regions of PD patients. Although there are several available medications to treat PD symptoms, these medications do not prevent the progression of the disease. Soluble epoxide hydrolase (sEH) plays a key role in inflammation associated with the pathogenesis of PD. Here we found that MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced neurotoxicity in the mouse striatum was attenuated by subsequent repeated administration of TPPU, a potent sEH inhibitor. Furthermore, deletion of the sEH gene protected against MPTP-induced neurotoxicity, while overexpression of sEH in the striatum significantly enhanced MPTP-induced neurotoxicity. Moreover, the expression of the sEH protein in the striatum from MPTP-treated mice or postmortem brain samples from patients with dementia of Lewy bodies (DLB) was significantly higher compared with control groups. Interestingly, there was a positive correlation between sEH expression and phosphorylation of α-synuclein in the striatum. Oxylipin analysis showed decreased levels of 8,9-epoxy-5Z,11Z,14Z-eicosatrienoic acid in the striatum of MPTP-treated mice, suggesting increased activity of sEH in this region. Interestingly, the expression of sEH mRNA in human PARK2 iPSC-derived neurons was higher than that of healthy control. Treatment with TPPU protected against apoptosis in human PARK2 iPSC-derived dopaminergic neurons. These findings suggest that increased activity of sEH in the striatum plays a key role in the pathogenesis of neurodegenerative disorders such as PD and DLB. Therefore, sEH may represent a promising therapeutic target for α-synuclein-related neurodegenerative disorders.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Cell Line; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Epoxide Hydrolases; HEK293 Cells; Humans; Lewy Bodies; Male; Mice; Mice, Inbred C57BL; MPTP Poisoning; Nerve Degeneration; Parkinson Disease; RNA, Messenger

Degeneration of noradrenergic locus coeruleus neurons occurs during the prodromal phase of Parkinson's disease and contributes to a variety of non-motor symptoms, e.g. depression, anxiety and REM sleep behavior disorder. This study was designed to establish the first locus coeruleus α-synucleinopathy mouse model, which should provide sufficient information about the time-course of noradrenergic neurodegeneration, replicate cardinal histopathological features of the human Parkinson's disease neuropathology and finally lead to robust histological markers, which are sufficient to assess the pathological changes in a quantitative and qualitative way. We show that targeted viral vector-mediated overexpression of human mutant A53T-α-synuclein in vivo in locus coeruleus neurons of wild-type mice resulted in progressive noradrenergic neurodegeneration over a time frame of 9 weeks. Observed neuronal cell loss was accompanied by progressive α-synuclein phosphorylation, formation of proteinase K-resistant α-synuclein-aggregates, accumulation of Ubi-1- and p62-positive inclusions in microglia and induction of progressive micro- and astrogliosis. Apart from this local pathology, abundant α-synuclein-positive axons were found in locus coeruleus output regions, indicating rapid anterograde axonal transport of A53T-α-synuclein. Taken together, we present the first model of α-synucleinopathy in the murine locus coeruleus, replicating essential morphological features of human Parkinson's disease pathology. This new model may contribute to the research on prodromal Parkinson's disease, in respect to pathophysiology and the development of disease-modifying therapy.

Topics: Alanine; alpha-Synuclein; Animals; Calcium-Binding Proteins; Disease Models, Animal; Endopeptidase K; Humans; Locus Coeruleus; Male; Mice; Mice, Inbred C57BL; Microfilament Proteins; Mutation; Nerve Tissue Proteins; Neuroglia; Neurons; Parkinson Disease; Protein Aggregates; Protein Transport; Threonine; Time Factors; Transduction, Genetic; Tyrosine 3-Monooxygenase

Accumulation of aggregated α-synuclein into Lewy bodies is thought to contribute to the onset and progression of dopaminergic neuron degeneration in Parkinson's disease (PD) and related disorders. Although protein aggregation is associated with perturbation of proteostasis, how α-synuclein aggregation affects the brain proteome and signaling remains uncertain. In a mouse model of α-synuclein aggregation, 6% of 6215 proteins and 1.6% of 8183 phosphopeptides changed in abundance, indicating conservation of proteostasis and phosphorylation signaling. The proteomic analysis confirmed changes in abundance of proteins that regulate dopamine synthesis and transport, synaptic activity and integrity, and unearthed changes in mRNA binding, processing and protein translation. Phosphorylation signaling changes centered on axonal and synaptic cytoskeletal organization and structural integrity. Proteostatic responses included a significant increase in the levels of Lmp7, a component of the immunoproteasome. Increased Lmp7 levels and activity were also quantified in postmortem human brains with PD and dementia with Lewy bodies. Functionally, the immunoproteasome degrades α-synuclein aggregates and generates potentially antigenic peptides. Expression and activity of the immunoproteasome may represent testable targets to induce adaptive responses that maintain proteome integrity and modulate immune responses in protein aggregation disorders.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Mice; Mice, Knockout; Parkinson Disease; Proteasome Endopeptidase Complex; Protein Aggregation, Pathological; Proteostasis

Dopaminergic neurodegeneration in Parkinson's disease (PD) is associated with abnormal dopamine metabolism by MAO-B (monoamine oxidase-B) and intracellular α-Synuclein (α-Syn) aggregates, called the Lewy body. However, the molecular relationship between α-Syn and MAO-B remains unclear. Here, we show that α-Syn directly binds to MAO-B and stimulates its enzymatic activity, which triggers AEP (asparagine endopeptidase; legumain) activation and subsequent α-Syn cleavage at N103, leading to dopaminergic neurodegeneration. Interestingly, the dopamine metabolite, DOPAL, strongly activates AEP, and the N103 fragment of α-Syn binds and activates MAO-B. Accordingly, overexpression of AEP in SNCA transgenic mice elicits α-Syn N103 cleavage and accelerates PD pathogenesis, and inhibition of MAO-B by Rasagiline diminishes α-Syn-mediated PD pathology and motor dysfunction. Moreover, virally mediated expression of α-Syn N103 induces PD pathogenesis in wild-type, but not MAO-B-null mice. Our findings thus support that AEP-mediated cleavage of α-Syn at N103 is required for the association and activation of MAO-B, mediating PD pathogenesis.

Topics: alpha-Synuclein; Animals; Cysteine Endopeptidases; Disease Models, Animal; Dopamine; Indans; Mice; Mice, Transgenic; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Parkinson Disease

Mutations in leucine-rich repeat kinase (LRRK2) are the most common cause of heritable Parkinson's disease (PD), and the most common mutations in LRRK2 lead to elevated kinase activity. For these reasons, inhibitors targeting LRRK2 have been the subject of intense research and development. However, it has been difficult to develop preclinical models that recapitulate PD-relevant LRRK2 phenotypes. The primary pathology in PD is the Lewy body (LB), which is a cytoplasmic aggregate of α-synuclein. The recent demonstration that LB-like aggregates of α-synuclein can be induced in primary neurons has provided a robust model for testing genetic modifiers of PD-relevant aggregation and neurodegeneration. In this study, we test the modulation of α-synuclein pathology by LRRK2 in primary neuron cultures using biochemistry and immunocytochemistry. We find that expression of familial mutant G2019S LRRK2 does not dramatically elevate the pathological burden of α-synuclein or neurodegeneration in neurons. We further test three LRRK2 inhibitors in two strains of wildtype neurons and find that even robust LRRK2 inhibition is insufficient to reduce α-synuclein pathology. LRRK2 inhibitors similarly had no effect in neurons with α-synuclein pathology seeded by human brain-derived pathological α-synuclein. Finally, we find that this lack of pathological modulation by LRRK2 was not confined to hippocampal neurons, but was also absent in midbrain dopaminergic neuron cultures. These data demonstrate that LRRK2 activity does not have more than minor effects on α-synuclein pathology in primary neurons, and more complex models may be needed to evaluate the ability of LRRK2 inhibitors to treat PD.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Cells, Cultured; Corpus Striatum; Disease Models, Animal; Embryo, Mammalian; Enzyme Inhibitors; Gene Expression Regulation; Hippocampus; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Neurons; Organ Culture Techniques; Parkinson Disease; Pyrimidines; Pyrroles; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is characterized by distinct motor and non-motor symptoms. Sleep disorders are the most frequent and challenging non-motor symptoms in PD patients, and there is growing evidence that they are a consequence of disruptions within the circadian system. PD is characterized by a progressive degeneration of the dorsal vagal nucleus and midbrain dopaminergic neurons together with an imbalance of many other neurotransmitters. Mutations in α-synuclein (SNCA), a protein modulating SNARE complex-dependent neurotransmission, trigger dominantly inherited PD variants and sporadic cases of PD. The A53T SNCA missense mutation is associated with an autosomal dominant early-onset familial PD. To test whether this missense mutation affects the circadian system, we analyzed the spontaneous locomotor behavior of non-transgenic wildtype mice and transgenic mice overexpressing mutant human A53T α-synuclein (A53T). The mice were subjected to entrained- and free-running conditions as well as to experimental jet lag. Furthermore, the vesicular glutamate transporter 2 (VGLUT2) in the suprachiasmatic nucleus (SCN) was analyzed by immunohistochemistry. Free-running circadian rhythm and, thus, circadian rhythm generation, were not affected in A53T mice. A53T mice entrained to the light⁻dark cycle, however, with an advanced phase angle of 2.65 ± 0.5 h before lights off. Moreover, re-entrainment after experimental jet lag was impaired in A53T mice. Finally, VGLUT2 immunoreaction was reduced in the SCN of A53T mice. These data suggest an impaired light entrainment of the circadian system in A53T mice.

Topics: alpha-Synuclein; Animals; Circadian Clocks; Disease Models, Animal; Gene Expression Regulation; Locomotion; Mice; Mice, Transgenic; Mutation; Parkinson Disease; Photic Stimulation; Synaptic Transmission; Up-Regulation

In the present study the effect of capsaicin was studied on PD model flies expressing human alpha synuclein. First the potential of scavenging superoxide anion and free radicals by capsaicin at doses of 20, 40, 80 and 100 μM was estimated. The PD flies were allowed to feed separately on the diet containg 20, 40, 80 and 100 μM of capsaicin, respectively, for 24 days. After 24 days of exposure, fly head homogenate was prepared from each group and was used to estimate glutathione (GSH), protein carbonyl (PC), dopamine content, lipid peroxidation (LPO), glutathione-S-transferase (GST) and monoamine oxidase (MAO) activity. A dose dependent significant increase in the potential of scavenging superoxide anions and free radicals by capsaicin was observed for the doses of 20, 40, 80 and 100 μM. The exposure of capsaicin not only significantly increased the GSH (max. by 1.37-fold), and dopamine (max. by 1.56-fold) content but also reduced LPO (max. by 1.8-fold), GST (max. by 1.26-fold), MAO activities (max. by 1.60-fold) and PC content (max. by 1.95-fold), compared to unexposed PD flies (p < 0.05). The results suggest the protective role of capsaicin against the PD symptoms.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Capsaicin; Disease Models, Animal; Dopamine; Drosophila; Free Radicals; Glutathione; Glutathione Transferase; Humans; Lipid Peroxidation; Monoamine Oxidase; Oxidative Stress; Parkinson Disease; Protein Carbonylation; Sensory System Agents; Superoxides

Activation of microglia by classical inflammatory mediators can convert astrocytes into a neurotoxic A1 phenotype in a variety of neurological diseases

Topics: alpha-Synuclein; Amyloid; Animals; Astrocytes; Disease Models, Animal; Humans; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Neuroprotective Agents; Parkinson Disease

Accumulating evidence suggests that the non-receptor tyrosine kinase c-Abl plays an important role in the progression of Parkinson's disease (PD) and c-Abl inhibition could be neuroprotective in PD and related α-synucleinopathies. Nilotinib, a c-Abl inhibitor, has shown improved motor and cognitive symptoms in PD patients. However, issues concerning blood-brain barrier (BBB) penetration, lack of selectivity and safety still remain. Radotinib HCl is a selective Bcr-Abl kinase inhibitor that not only effectively access the brain, but also exhibits greater pharmacokinetic properties and safety profiles compared to Nilotinib and other c-Abl inhibitors. Here, we show the neuroprotective efficacy of Radotinib HCl, a brain penetrant c-Abl inhibitor, in a pre-clinical model of PD. Importantly, in vitro studies demonstrate that the treatment of Radotinib HCl protects the α-synuclein preformed fibrils (PFF)-induced neuronal toxicity, reduces the α-synuclein PFF-induced Lewy bodies (LB)/Lewy neurites (LN)-like pathology and inhibits the α-synuclein PFF-induced c-Abl activation in primary cortical neurons. Furthermore, administration of Radotinib HCl inhibits c-Abl activation and prevents dopaminergic neuron loss, neuroinflammation and behavioral deficits following α-synuclein PFF-induced toxicity in vivo. Taken together, our findings indicate that Radotinib HCl has beneficial neuroprotective effects in PD and provides an evidence that selective and brain permeable c-Abl inhibitors can be potential therapeutic agents for the treatment of PD and related α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Blood-Brain Barrier; Brain; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Lewy Bodies; Mice; Nerve Degeneration; Neuroprotective Agents; Parkinson Disease; Proto-Oncogene Proteins c-abl; Pyrimidines; Sesquiterpenes

α-synuclein abnormal accumulation and mitochondria dysfunction are involved in the pathogenesis of Parkinson's disease. Selective autophagy of mitochondria (mitophagy) is a crucial component of the network controlling the mitochondrial homeostasis. However, the underlying mechanism that mutant α-synuclein induces mitochondrial abnormality through mitophagy impairment is not fully understood. Here, we showed that mutant A53T α-synuclein accumulation impaired mitochondrial function and Parkin-mediated mitophgy in α-synucleinA53T model. α-synucleinA53T overexpression caused p38 MAPK activation, then p38 MAPK directly phosphorylated Parkin at serine 131 to disrupt the Parkin's protective function. The p38 MAPK inhibition significantly reduced cellular apoptosis, restored mitochondrial membrane potential as well as increased synaptic density both in SN4741 cells and primary midbrain neurons. These findings show that the p38 MAPK-Parkin signaling pathway regulates mitochondrial homeostasis and neuronal degeneration, which may be a potential therapeutic strategy of PD via enhancing mitochondrial turn-over and maintenance.

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Enzyme Activation; Humans; Imidazoles; Mice, Transgenic; Mitochondria; Mitophagy; Mutant Proteins; Neurons; p38 Mitogen-Activated Protein Kinases; Parkinson Disease; Phosphorylation; Phosphoserine; Protein Kinases; Pyridines; Synapses; Tyrosine 3-Monooxygenase; Ubiquitin-Protein Ligases

The aggregation of α-synuclein, an intrinsically disordered protein that is highly abundant in neurons, is closely associated with the onset and progression of Parkinson's disease. We have shown previously that the aminosterol squalamine can inhibit the lipid induced initiation process in the aggregation of α-synuclein, and we report here that the related compound trodusquemine is capable of inhibiting not only this process but also the fibril-dependent secondary pathways in the aggregation reaction. We further demonstrate that trodusquemine can effectively suppress the toxicity of α-synuclein oligomers in neuronal cells, and that its administration, even after the initial growth phase, leads to a dramatic reduction in the number of α-synuclein inclusions in a Caenorhabditis elegans model of Parkinson's disease, eliminates the related muscle paralysis, and increases lifespan. On the basis of these findings, we show that trodusquemine is able to inhibit multiple events in the aggregation process of α-synuclein and hence to provide important information about the link between such events and neurodegeneration, as it is initiated and progresses. Particularly in the light of the previously reported ability of trodusquemine to cross the blood-brain barrier and to promote tissue regeneration, the present results suggest that this compound has the potential to be an important therapeutic candidate for Parkinson's disease and related disorders.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Cell Line; Cholestanes; Disease Models, Animal; Humans; Neurons; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; Spermine

Many studies have demonstrated that mesencephalic astrocyte-derived neurotrophic factor (MANF) has been shown protective effects on neurotoxin based models of Parkinson's disease (PD). It still remains unclear whether MANF can rescue dopaminergic (DA) neurons in an α-synuclein model. Glial cell line-derived neurotrophic factor (GDNF) and its related neurturin (NRTN) can protect DA neurons in the neurotoxin but not α-synuclein animal models of PD, it failed in the clinical trials. Since α-synuclein model can better mimic the progression of human PD, in our study we overexpressed MANF specifically in DA neurons by using an α-synuclein Caenorhabditis elegans (C. elegans) model. Our results showed MANF alleviated progressive neuronal degeneration and prevented locomotion defects. Indeed, MANF can protect cilia of DA neurons at an early stage, suggested that MANF participated in the whole process of neuronal degeneration. Furthermore, we found MANF facilitated the removal of misfolded α-synuclein proteins and rescued the function of damaged DA neurons. By using RNAi approach, we inhibited ER stress and autophagy related genes and effects of MANF were decreased, which demonstrated ER stress and autophagy pathways were involved in the MANF-mediated neuroprotection. Our study suggests MANF exhibits potential as a neuroprotective agent for PD therapy.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Endoplasmic Reticulum Stress; Humans; Locomotion; Nerve Degeneration; Nerve Growth Factors; Neuroprotection; Parkinsonian Disorders

Parkinson disease (PD) is the second most common neurodegenerative disorder and the leading neurodegenerative cause of motor disability. Pathologic accumulation of aggregated alpha synuclein (AS) protein in brain, and imbalance in the nigrostriatal system due to the loss of dopaminergic neurons in the substantia nigra- pars compacta, are hallmark features in PD. AS aggregation and propagation are considered to trigger neurotoxic mechanisms in PD, including mitochondrial deficits and oxidative stress. The eukaryotic elongation factor-2 kinase (eEF2K) mediates critical regulation of dendritic mRNA translation and is a crucial molecule in diverse forms of synaptic plasticity. Here we show that eEF2K activity, assessed by immuonohistochemical detection of eEF2 phosphorylation on serine residue 56, is increased in postmortem PD midbrain and hippocampus. Induction of aggressive, AS-related motor phenotypes in a transgenic PD M83 mouse model also increased brain eEF2K expression and activity. In cultures of dopaminergic N2A cells, overexpression of wild-type human AS or the A53T mutant increased eEF2K activity. eEF2K inhibition prevented the cytotoxicity associated with AS overexpression in N2A cells by improving mitochondrial function and reduced oxidative stress. Furthermore, genetic deletion of the eEF2K ortholog efk-1 in C. elegans attenuated human A53T AS induced defects in behavioural assays reliant on dopaminergic neuron function. These data suggest a role for eEF2K activity in AS toxicity, and support eEF2K inhibition as a potential target in reducing AS-induced oxidative stress in PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Caenorhabditis elegans; Cell Line, Tumor; Disease Models, Animal; Elongation Factor 2 Kinase; Female; Humans; Male; Mice; Mice, Transgenic; Mutation; Neuroblastoma; Organ Culture Techniques; Parkinson Disease; Prion Proteins; RNA, Small Interfering; Scleroproteins

Parkinson's disease is diagnosed upon the presentation of motor symptoms, resulting from substantial degeneration of dopaminergic neurons in the midbrain. Prior to diagnosis, there is a lengthy prodromal stage in which non-motor symptoms, including olfactory deficits (hyposmia), develop. There is limited information about non-motor impairments and there is a need for directed research into these early pathogenic cellular pathways that precede extensive dopaminergic death in the midbrain. The protein tau has been identified as a genetic risk factor in the development of sporadic PD. Tau knockout mice have been reported as an age-dependent model of PD, and this study has demonstrated that they develop motor deficits at 15-months-old. We have shown that at 7-month-old tau knockout mice present with an overt hyposmic phenotype. This olfactory deficit correlates with an accumulation of α-synuclein, as well as autophagic impairment, in the olfactory bulb. This pathological feature becomes apparent in the striatum and substantia nigra of 15-month-old tau knockout mice, suggesting the potential for a spread of disease. Initial primary cell culture experiments have demonstrated that ablation of tau results in the release of α-synuclein enriched exosomes, providing a potential mechanism for disease spread. These alterations in α-synuclein level as well as a marked autophagy impairment in the tau knockout primary cells recapitulate results seen in the animal model. These data implicate a pathological role for tau in early Parkinson's disease.

Topics: Age Factors; alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Exosomes; Mice; Mice, Transgenic; Microscopy, Electron, Transmission; Neurons; Odorants; Olfaction Disorders; Olfactory Bulb; Parkinson Disease; Psychomotor Performance; Sequestosome-1 Protein; tau Proteins

Misfolding and accumulation of cellular protein aggregates are pathological hallmarks of aging and neurodegeneration. One such protein is α-synuclein, which when misfolded, forms aggregates and disrupts normal cellular functions of the neurons causing Parkinson's disease. Nutritional interventions abundant in pharmacologically potent polyphenols have demonstrated a therapeutic role for combating protein aggregation associated with neurodegeneration. The current study hypothesized that Alaskan bog blueberry (Vaccinum uliginosum), which is high in polyphenolic content, will reduce α-synuclein expression in a model of Caenorhabditis elegans (C. elegans). We observed that blueberry extracts attenuated α-synuclein protein expression, improved healthspan in the form of motility and restored lipid content in the transgenic strain of C. elegans expressing human α-synuclein. We also found reduced gene expression levels of sir-2.1 (ortholog of mammalian Sirtuin 1) in blueberry treated transgenic animals indicating that the beneficial effects of blueberries could be mediated through partial reduction of sirtuin activity. This therapeutic effect of the blueberries was attributed to its xenohormetic properties. The current results highlight the role of Alaskan blueberries in mediating inhibition of sir-2.1 as a novel therapeutic approach to improving pathologies of protein misfolding diseases. Finally, our study warrants further investigation of the structure, and specificity of such small molecules from indigenous natural compounds and its role as sirtuin regulators.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Down-Regulation; Gene Expression Regulation; Humans; Plant Extracts; Polyphenols; Protein Aggregates; Sirtuins; Vaccinium

The loss of dopaminergic neurons and α-synuclein accumulation are major hallmarks of Parkinson's disease (PD), and it has been suggested that a major mechanism of α-synuclein toxicity is microglial activation. The lack of animal models that properly reproduce PD, and particularly the underlying synucleinopathy, has hampered the clarification of PD mechanisms and the development of effective therapies. Here, we used neurospecific adeno-associated viral vectors serotype 9 coding for either the wild-type or mutated forms of human alpha-synuclein (WT and SynA53T, respectively) under the control of a synapsin promoter to further induce a marked dopaminergic neuron loss together with an important microglial neuroinflammatory response. Overexpression of neuronal alpha-synuclein led to increased expression of angiotensin type 1 receptors and NADPH oxidase activity, together with a marked increase in the number of OX-6-positive microglial cells and expression of markers of phagocytic activity (CD68) and classical pro-inflammatory/M1 microglial phenotype markers such as inducible nitric oxide synthase, tumor necrosis factor alpha, interleukin-1β, and IL-6. Moreover, a significant decrease in the expression of markers of immunoregulatory/M2 microglial phenotype such as the enzyme arginase-1 was constantly observed. Interestingly, alpha-synuclein-induced changes in microglial phenotype markers and dopaminergic neuron death were inhibited by simultaneous treatment with the angiotensin type 1 blockers candesartan or telmisartan. Our results suggest the repurposing of candesartan and telmisartan as a neuroprotective strategy for PD.

Topics: alpha-Synuclein; Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Biphenyl Compounds; Calcium-Binding Proteins; Cell Death; Cytokines; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Encephalitis; Glial Fibrillary Acidic Protein; Green Fluorescent Proteins; Humans; Male; Microfilament Proteins; Microscopy, Confocal; Mutation; Rats; Rats, Sprague-Dawley; Synapsins; Telmisartan; Tetrazoles; Transduction, Genetic; Tyrosine 3-Monooxygenase

Act5C: actin 5C; a.E.: after eclosion; Atg5: autophagy-related 5; Atg8a/LC3: autophagy-related 8a; CMA: chaperone-mediated autophagy; DHE: dihydroethidium; elav: embryonic lethal abnormal vision; eMI: endosomal microautophagy; ESCRT: endosomal sorting complexes required for transport; GABARAP: GABA typeA receptor-associated protein; Hsc70-4: heat shock protein cognate 4; HSPA8/Hsc70: heat shock protein family A (Hsp70) member 8; LAMP2: lysosomal associated membrane protein 2; MDA: malondialdehyde; PA-mCherry: photoactivable mCherry; PBS: phosphate-buffered saline; PCR: polymerase chain reaction; PD: Parkinson disease; Ref(2)P/p62: refractory to sigma P; ROS: reactive oxygen species; RpL32/rp49: ribosomal protein L32; RT-PCR: reverse transcription polymerase chain reaction; SING: startle-induced negative geotaxis; SNCA/α-synuclein: synuclein alpha; SQSTM1/p62: sequestosome 1; TBS: Tris-buffered saline; UAS: upstream activating sequence.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Brain; Disease Models, Animal; Drosophila; Humans; Locomotion; Lysosomal-Associated Membrane Protein 2; Neuroprotection; Oxidative Stress; Parkinson Disease; Phenotype; Signal Transduction

Accumulation of α-synuclein (α-syn) is a neuropathological hallmark of synucleinopathies. To date, no selective α-syn positron emission tomography (PET) radiotracer has been identified. Our objective was to develop the first original, selective, and specific α-syn PET radiotracer. Chemical design inspired from three structural families that demonstrated interesting α-syn binding characteristics was used as a starting point. Bioinformatics modeling of α-syn fibrils was then employed to select the best molecular candidates before their syntheses. An in vitro binding assay was performed to evaluate the affinity of the compounds. Radiotracer specificity and selectivity were assessed by in vitro autoradiography and in vivo PET studies in animal (rodents) models. Finally, gold standard in vitro autoradiography with patients' postmortem tissues was performed to confirm/infirm the α-syn binding characteristics. Two compounds exhibited a good brain availability and bound to α-syn and Aβ fibrils in a rat model. In contrast, no signal was observed in a mouse model of synucleinopathy. Experiments in human tissues confirmed these negative results.

Topics: alpha-Synuclein; Animals; Autoradiography; Biological Availability; Brain; Disease Models, Animal; Drug Design; Fluorine Radioisotopes; Humans; Lewy Bodies; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molecular Docking Simulation; Parkinson Disease; Positron-Emission Tomography; Protein Binding; Radiopharmaceuticals; Rats; Rats, Sprague-Dawley

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra of the midbrain. Dopamine agonists help the patients with PD by reversing the dopamine depletion and related motor deficits. In the present work, cabergoline, a potent ergot dopamine agonist, was given in the form of cabergoline alginate nanocomposite (CANC) to the PD model flies to study its effects on climbing ability, activity pattern, life span, lipid peroxidation, glutathione (GSH) content, glutathione-S-transferase (GST) activity, dopamine content, protein carbonyl content, mean gray-scale values, and caspase-3 and caspase-9 activities. Cabergoline alginate nanocomposite was synthesized by adding the cabergoline solution in the warm aqueous solution of sodium alginate; The synthesized CANC was characterized using fourier transform (FTIR) infrared spectroscopy, transmission electron microscopy (TEM), and UV-Visible spectroscopic techniques. The synthesized CANC having the final doses of 1, 2, and 3 μM was supplemented with diet and the flies were allowed to feed on it for 24 days. Cabergoline alginate nanocomposite significantly increases climbing ability, reduces lipid peroxidation, GST activity, protein carbonyl content, caspase 3/9 activity, mean gray-scale values, and increases the GSH as well as dopamine content in a dose-dependent manner. The results of this study suggest that CANC is potent in delaying and reducing the symptoms of PD.

Topics: Alginates; alpha-Synuclein; Animals; Animals, Genetically Modified; Behavior, Animal; Cabergoline; Disease Models, Animal; Dopamine; Dopamine Agonists; Dose-Response Relationship, Drug; Drosophila melanogaster; Longevity; Nanocomposites; Oxidative Stress; Parkinson Disease

CYP2J proteins are present in the neural cells of human and rodent brain regions. The aim of this study was to investigate the role of brain CYP2J in Parkinson's disease. Rats received right unilateral injection with lipopolysaccharide (LPS) or 6-hydroxydopamine (6-OHDA) in the substantia nigra following transfection with or without the CYP2J3 expression vector. Compared with LPS-treated rats, CYP2J3 transfection significantly decreased apomorphine-induced rotation by 57.3% at day 12 and 47.0% at day 21 after LPS treatment; moreover, CYP2J3 transfection attenuated the accumulation of

Topics: alpha-Synuclein; Animals; Apomorphine; Brain; Cell Line, Tumor; Chromatin Immunoprecipitation; Cytochrome P-450 Enzyme System; Disease Models, Animal; Dopaminergic Neurons; Humans; Lipopolysaccharides; Male; Myeloid Differentiation Factor 88; NF-E2-Related Factor 2; Oxidopamine; Parkinson Disease; Rats; Rats, Wistar; Signal Transduction; Toll-Like Receptor 4

The involvement of DNA damage and repair in aging processes is well established. Aging is an unequivocal risk factor for chronic neurodegenerative diseases, underscoring the relevance of investigations into the role that DNA alterations may have in the pathogenesis of these diseases. Consistently, even moderate impairment of DNA repair systems facilitates the onset of pathological features typical of PD that include derangement of the dopaminergic system, mitochondrial dysfunction, and alpha-synuclein stress. The latter establishes a connection between reduced DNA repair capacity and a cardinal feature of PD, alpha-synuclein pathology. It remains to be determined, however, whether alpha-synuclein stress activates in vivo the canonical signaling cascade associated with DNA damage, which is centered on the kinase ATM and substrates such as γH2Ax and 53BP1. Addressing these issues would shed light on age-related mechanisms impinging upon PD pathogenesis and neurodegeneration in particular. We analyzed two different synucleinopathy PD mouse models based either on intranigral delivery of AAV-expressing human alpha-synuclein, or intrastriatal injection of human alpha-synuclein pre-formed fibrils. In both cases, we detected a significant increase in γH2AX and 53BP1 foci, and in phospho-ATM immunoreactivity in dopaminergic neurons, which collectively indicate DNA damage and activation of the DNA damage response. Mechanistic experiments in cell cultures indicate that activation of the DNA damage response is caused, at least in part, by pro-oxidant species because it is prevented by exogenous or endogenous antioxidants, which also rescue mitochondrial anomalies caused by proteotoxic alpha-synuclein. These in vivo and in vitro findings reveal that the cellular stress mediated by alpha-synuclein-a pathological hallmark in PD-elicits DNA damage and activates the DNA damage response. The toxic cascade leading to DNA damage involves oxidant stress and mitochondrial dysfunction The data underscore the importance of DNA quality control for preservation of neuronal integrity and protection against neurodegenerative processes.

Topics: alpha-Synuclein; Animals; Ataxia Telangiectasia Mutated Proteins; Cell Line, Tumor; Disease Models, Animal; DNA Damage; DNA Repair; Dopaminergic Neurons; Histones; Humans; Mice; Mice, Inbred C57BL; Mitochondria; Parkinson Disease; Reactive Oxygen Species; Substantia Nigra; Tumor Suppressor p53-Binding Protein 1

Previously we have shown that developmental exposure to the heavy metal lead (Pb) resulted in latent cognitive impairment, upregulation of biomarkers and pathology associated with both the tau and amyloid pathways, however, the impact on Alpha Synuclein (α-Syn) and its relationship to these pathways and their connection to cognitive performance warrant further elucidation.. The present study determined the impact of developmental Pb exposure on the α-Syn pathways in a mouse model knock-out (KO) for murine tau gene and in differentiated human neuroblastoma SHSY5Y cell line exposed to a series of Pb concentrations.. Western blot analysis and RT-PCR were used to assess the levels of intermediates in the tau and α-Syn pathways following postnatal Pb exposure on aged mice lacking tau gene and in differentiated SHSY5Y cells on day 3 and day 6 after the Pb exposure had ceased.. Early life Pb exposure is accompanied by latent up-regulation in α-Syn in these mice. Furthermore, prior exposure to Pb in-vitro also resulted in an increase in α-Syn, its phosphorylated forms, as well as an increase in glycogen synthase kinase 3β (GSK-3β) and Caspase-3.. An environmental agent can act as a latent inducer of both α-Syn and associated kinases that are involved in tau hyperphosphorylation and may allude to the interactive nature of these two neurodegenerative pathways.

Topics: alpha-Synuclein; Animals; Caspase 3; Cell Line, Tumor; Disease Models, Animal; Glycogen Synthase Kinase 3 beta; Green Fluorescent Proteins; Humans; Lead; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neuroblastoma; tau Proteins; Tauopathies; Up-Regulation

Synucleinopathies of the aging population are an heterogeneous group of neurological disorders that includes Parkinson's disease (PD) and dementia with Lewy bodies (DLB) and are characterized by the progressive accumulation of α-synuclein in neuronal and glial cells. Toll-like receptor 2 (TLR2), a pattern recognition immune receptor, has been implicated in the pathogenesis of synucleinopathies because TLR2 is elevated in the brains of patients with PD and TLR2 is a mediator of the neurotoxic and pro-inflammatory effects of extracellular α-synuclein aggregates. Therefore, blocking TLR2 might alleviate α-synuclein pathological and functional effects. For this purpose, herein, we targeted TLR2 using a functional inhibitory antibody (anti-TLR2).. Two different human α-synuclein overexpressing transgenic mice were used in this study. α-synuclein low expresser mouse (α-syn-tg, under the PDGFβ promoter, D line) was stereotaxically injected with TLR2 overexpressing lentivirus to demonstrate that increment of TLR2 expression triggers neurotoxicity and neuroinflammation. α-synuclein high expresser mouse (α-Syn-tg; under mThy1 promoter, Line 61) was administrated with anti-TLR2 to examine that functional inhibition of TLR2 ameliorates neuropathology and behavioral defect in the synucleinopathy animal model. In vitro α-synuclein transmission live cell monitoring system was used to evaluate the role of TLR2 in α-synuclein cell-to-cell transmission.. We demonstrated that administration of anti-TLR2 alleviated α-synuclein accumulation in neuronal and astroglial cells, neuroinflammation, neurodegeneration, and behavioral deficits in an α-synuclein tg mouse model of PD/DLB. Moreover, in vitro studies with neuronal and astroglial cells showed that the neuroprotective effects of anti-TLR2 antibody were mediated by blocking the neuron-to-neuron and neuron-to-astrocyte α-synuclein transmission which otherwise promotes NFκB dependent pro-inflammatory responses.. This study proposes TLR2 immunotherapy as a novel therapeutic strategy for synucleinopathies of the aging population.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Immunotherapy; Lewy Body Disease; Mice; Mice, Transgenic; Nerve Degeneration; Parkinsonian Disorders; Toll-Like Receptor 2

Recently, we identified the yeast red pigment (RP), a polymer of 1-(5'-Phosphoribosyl)-5-aminoimidazole, as a novel potential anti-amyloid agent for the therapy of neurodegenerative diseases. The purpose of this study was to further validate RP for treatment of Parkinson's disease (PD) and to clarify molecular mechanisms involved in the reduction of amyloid cytotoxicity. We investigated RP effects in vivo using Saccharomyces cerevisiae and Drosophila melanogaster PD models. Western blot analysis revealed reduction in the levels of insoluble α-synuclein in both models, while soluble α-synuclein decreased only in Drosophila. In both models RP significantly reduced α-synuclein cytotoxicity, as was revealed by immunohistochemistry in Drosophila (p < 0.001, n = 27 flies per genotype/assay) and by flow cytometry in yeast (p < 0.05). Data obtained from the yeast PD model suggests that RP antitoxic effects are associated with a drop in ROS accumulation, and slower cellular transition from the early to late apoptotic stage. Using Drosophila brain tissue sections, we have demonstrated that RP helps to compensate for an α-synuclein-mediated reduction in the number of dopaminergic neurons and leads to better performance in animal climbing tests (p < 0.001, n = 120-150 flies per genotype/assay). Taken together, these results demonstrate the potential of RP for the treatment of PD, at least in model systems.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Drosophila melanogaster; Drosophila Proteins; Humans; Parkinson Disease; Saccharomyces cerevisiae

The accumulation of specific phosphorylated protein aggregates in the brain is a hallmark of severe neurodegenerative disorders. Specifically, hyperphosphorylated tau (hp-tau) accumulates in Alzheimer disease, frontotemporal dementia with Parkinsonism linked to chromosome 17, and progressive supranuclear palsy; furthermore, phosphorylated α-synuclein (p-αSyn) accumulates in Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. Moreover, codeposition of different pathological protein aggregates is common in the brains of individuals with neurodegenerative diseases. In the present report, we describe the detection of p-αSyn aggregates in the brain of rTg4510 mice that overexpress human P301L mutant tau. Immunohistochemistry showed that hp-tau and p-αSyn aggregates were found within the same neuronal cells in rTg4510 mice and increased with age. Moreover, semiquantitative analysis revealed a significant regional correlation between hp-tau and p-αSyn accumulation. These results indicate that endogenous mouse αSyn protein is phosphorylated and accumulates with hp-tau aggregation in neurons and suggest that the overexpression of human P301L mutant tau may enhance endogenous αSyn phosphorylation and aggregation via a similar hyperphosphorylation mechanism in vivo. This synergic effect between tau and αSyn accumulation may exacerbate the pathology of several neurodegenerative disorders that show a cooccurrence of hp-tau and p-αSyn aggregation.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Phosphorylation; Protein Aggregation, Pathological; tau Proteins; Tauopathies

Parkinson's disease (PD) is a common, progressive neurodegenerative disorder characterized by classical motor dysfunction and is associated with α-synuclein-immunopositive pathology and the loss of dopaminergic neurons in the substantia nigra (SN). Several missense mutations in the α-synuclein gene SCNA have been identified as cause of inherited PD, providing a practical strategy to generate genetically modified animal models for PD research. Since minipigs share many physiological and anatomical similarities to humans, we proposed that genetically modified minipigs carrying PD-causing mutations can serve as an ideal model for PD research. In the present study, we attempted to model PD by generating Guangxi Bama minipigs with three PD-causing missense mutations (E46K, H50Q and G51D) in SCNA using CRISPR/Cas9-mediated gene editing combining with somatic cell nuclear transfer (SCNT) technique. We successfully generated a total of eight SCNT-derived Guangxi Bama minipigs with the desired heterozygous SCNA mutations integrated into genome, and we also confirmed by DNA sequencing that these minipigs expressed mutant α-synuclein at the transcription level. However, immunohistochemical analysis was not able to detect PD-specific pathological changes such as α-synuclein-immunopositive pathology and loss of SN dopaminergic neurons in the gene-edited minipigs at 3 months of age. In summary, we successfully generated Guangxi Bama minipigs harboring three PD-casusing mutations (E46K, H50Q and G51D) in SCNA. As they continue to develop, these gene editing minipigs need to be regularly teseted for the presence of PD-like pathological features in order to validate the use of this large-animal model in PD research.

Topics: alpha-Synuclein; Animals; Clustered Regularly Interspaced Short Palindromic Repeats; CRISPR-Cas Systems; Disease Models, Animal; Dopaminergic Neurons; Mutation, Missense; Parkinson Disease; Substantia Nigra; Swine; Swine, Miniature

Aggregation of α-synuclein, the hallmark of α-synucleinopathies such as Parkinson's disease, occurs in various glycosphingolipidoses. Although α-synuclein aggregation correlates with deficiencies in the lysosomal degradation of glycosphingolipids (GSL), the mechanism(s) involved in this aggregation remains unclear. We previously described the aggregation of α-synuclein in Krabbe's disease (KD), a neurodegenerative glycosphingolipidosis caused by lysosomal deficiency of galactosyl-ceramidase (GALC) and the accumulation of the GSL psychosine. Here, we used a multi-pronged approach including genetic, biophysical and biochemical techniques to determine the pathogenic contribution, reversibility, and molecular mechanism of aggregation of α-synuclein in KD. While genetic knock-out of α-synuclein reduces, but does not completely prevent, neurological signs in a mouse model of KD, genetic correction of GALC deficiency completely prevents α-synuclein aggregation. We show that psychosine forms hydrophilic clusters and binds the C-terminus of α-synuclein through its amino group and sugar moiety, suggesting that psychosine promotes an open/aggregation-prone conformation of α-synuclein. Dopamine and carbidopa reverse the structural changes of psychosine by mediating a closed/aggregation-resistant conformation of α-synuclein. Our results underscore the therapeutic potential of lysosomal correction and small molecules to reduce neuronal burden in α-synucleinopathies, and provide a mechanistic understanding of α-synuclein aggregation in glycosphingolipidoses.

Topics: alpha-Synuclein; Animals; Brain; Cell Line; Disease Models, Animal; Dopamine; Galactosylceramidase; Humans; Leukodystrophy, Globoid Cell; Lysosomes; Mice; Mice, Inbred C57BL; Neurons; Psychosine

AEP is an age-dependent lysosomal asparaginyl endopeptidase that cleaves numerous substrates including tau and α-synuclein and mediates their pathological roles in neurodegenerative diseases. However, the molecular mechanism regulating this critical protease remains incompletely understood. Here, we show that Akt phosphorylates AEP on residue T322 upon brain-derived neurotrophic factor (BDNF) treatment and triggers its lysosomal translocation and inactivation. When BDNF levels are reduced in neurodegenerative diseases, AEP T322 phosphorylation is attenuated. Consequently, AEP is activated and translocates into the cytoplasm, where it cleaves both tau and α-synuclein. Remarkably, the unphosphorylated T322A mutant increases tau or α-synuclein cleavage by AEP and augments cell death, whereas phosphorylation mimetic T322E mutant represses these effects. Interestingly, viral injection of T322E into Tau P301S mice antagonizes tau N368 cleavage and tau pathologies, rescuing synaptic dysfunction and cognitive deficits. By contrast, viral administration of T322A into young α-SNCA mice elicits α-synuclein N103 cleavage and promotes dopaminergic neuronal loss, facilitating motor defects. Therefore, our findings support the notion that BDNF contributes to the pathogenesis of neurodegenerative diseases by suppressing AEP via Akt phosphorylation.

Topics: alpha-Synuclein; Animals; Brain; Brain-Derived Neurotrophic Factor; Cell Line, Tumor; Cysteine Endopeptidases; Disease Models, Animal; HEK293 Cells; Humans; Lysosomes; Mice; Mice, Knockout; Mutation; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Phosphorylation; Primary Cell Culture; Proto-Oncogene Proteins c-akt; Rats; Recombinant Proteins; tau Proteins

The deposition of pathologic misfolded proteins in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, frontotemporal dementia and amyotrophic lateral sclerosis is hypothesized to burden protein homeostatic (proteostatic) machinery, potentially leading to insufficient capacity to maintain the proteome. This hypothesis has been supported by previous work in our laboratory, as evidenced by the perturbation of cytosolic protein solubility in response to amyloid plaques in a mouse model of Alzheimer's amyloidosis. In the current study, we demonstrate changes in proteome solubility are a common pathology to mouse models of neurodegenerative disease. Pathological accumulations of misfolded tau, α-synuclein and mutant superoxide dismutase 1 in CNS tissues of transgenic mice were associated with changes in the solubility of hundreds of CNS proteins in each model. We observed that changes in proteome solubility were progressive and, using the rTg4510 model of inducible tau pathology, demonstrated that these changes were dependent upon sustained expression of the primary pathologic protein. In all of the models examined, changes in proteome solubility were robust, easily detected, and provided a sensitive indicator of proteostatic disruption. Interestingly, a subset of the proteins that display a shift towards insolubility were common between these different models, suggesting that a specific subset of the proteome is vulnerable to proteostatic disruption. Overall, our data suggest that neurodegenerative proteinopathies modeled in mice impose a burden on the proteostatic network that diminishes the ability of neural cells to prevent aberrant conformational changes that alter the solubility of hundreds of abundant cellular proteins.

Topics: Age Factors; alpha-Synuclein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Central Nervous System; Chromatography, High Pressure Liquid; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Transgenic; Mutation; Neurodegenerative Diseases; Neurofibrillary Tangles; Presenilin-1; Protein Folding; Proteome; Solubility; Tandem Mass Spectrometry; tau Proteins

Mitochondrial dysfunction plays a central role in the pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD). This study was designed to determine whether the dipeptide carnosine, which has been shown to protect against oxidative stress and mitochondrial dysfunction, would provide a beneficial effect on mitochondrial function in the Thy1-aSyn mouse model of PD. Thy1-aSyn mice, which overexpress wild-type human alpha-synuclein (aSyn), exhibit progressive non-motor and motor deficits as early as 2 months of age. Two-month old Thy1-aSyn mice and wild-type littermates were randomly assigned to treatment groups with intranasal (IN) and drinking water carnosine, with controls receiving 10 μl of sterile waster intranasally or carnosine-free drinking water, respectively. After two months of treatment, mice were euthanized, and the midbrain was dissected for the evaluation of the gene expression and mitochondrial function. Transcriptional deficiencies associated with the aSyn overexpression in Thy1-aSyn mice were related to ribosomal and mitochondrial function. These deficiencies were attenuated by IN carnosine administration, which increased the expression of mitochondrial genes and enhanced mitochondrial function. These results suggest a potential neuroprotective role for IN-carnosine in PD patients.

Topics: Administration, Intranasal; alpha-Synuclein; Animals; Carnosine; Corpus Striatum; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Mitochondria; Parkinson Disease; Thy-1 Antigens; Transcriptome

Dementia with Lewy bodies (DLB) is characterized by neuronal deficits and

Topics: alpha-Synuclein; Animals; Brain; Ceftriaxone; China; Dementia; Disease Models, Animal; Hippocampus; Lewy Bodies; Lewy Body Disease; Magnetic Resonance Imaging; Male; Neurodegenerative Diseases; Neurons; Rats; Rats, Wistar

Parkinson's disease (PD) is characterized by intracellular alpha-synuclein (α-syn) inclusions, progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNpc), and activation of the innate and adaptive immune systems. Disruption of immune signaling between the central nervous system (CNS) and periphery, such as through targeting the chemokine receptor type 2 (CCR2) or the major histocompatibility complex II (MHCII), is neuroprotective in rodent models of PD, suggesting a key role for innate and adaptive immunity in disease progression. The purpose of this study was to investigate whether genetic knockout or RNA silencing of the class II transactivator (CIITA), a transcriptional co-activator required for MHCII induction, is effective in reducing the neuroinflammation and neurodegeneration observed in an α-syn mouse model of PD.. In vitro, we utilized microglia cultures from WT or CIITA -/- mice treated with α-syn fibrils to investigate inflammatory iNOS expression and antigen processing via immunocytochemistry (ICC). In vivo, an adeno-associated virus (AAV) was used to overexpress α-syn in WT and CIITA -/- mice as a model for PD. Concurrently with AAV-mediated overexpression of α-syn, WT mice received CIITA-targeted shRNAs packaged in lentiviral constructs. Immunohistochemistry and flow cytometry were used to assess inflammation and peripheral cell infiltration at 4 weeks post transduction, and unbiased stereology was used 6 months post transduction to assess neurodegeneration.. Using ICC and DQ-ovalbumin, we show that CIITA -/- microglial cultures failed to upregulate iNOS and MHCII expression, and had decreased antigen processing in response to α-syn fibrils when compared to WT microglia. In vivo, global knock-out of CIITA as well as local knockdown using lentiviral shRNAs targeting CIITA attenuated MHCII expression, peripheral immune cell infiltration, and α-syn-induced neurodegeneration.. Our data provide evidence that CIITA is required for α-syn-induced MHCII induction and subsequent infiltration of peripheral immune cells in an α-syn mouse model of PD. Additionally, we demonstrate that CIITA in the CNS drives neuroinflammation and neurodegeneration. These data provide further support that the disruption or modulation of antigen processing and presentation via CIITA is a promising target for therapeutic development in preclinical animal models of PD.

Topics: alpha-Synuclein; Animals; Antigens, CD; Disease Models, Animal; Encephalitis; Female; Functional Laterality; Gene Expression Regulation, Enzymologic; Green Fluorescent Proteins; Leukocytes, Mononuclear; Male; Mesencephalon; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Nitric Oxide Synthase Type II; Nuclear Proteins; Parkinson Disease; RNA, Small Interfering; Trans-Activators; Tyrosine 3-Monooxygenase

Patients with Parkinson's disease (PD) often have non-motor symptoms related to gastrointestinal (GI) dysfunction, such as constipation and delayed gastric emptying, which manifest prior to the motor symptoms of PD. Increasing evidence indicates that changes in the composition of the gut microbiota may be related to the pathogenesis of PD. However, it is unclear how GI dysfunction occurs and how gut microbial dysbiosis is caused. We investigated whether a neurotoxin model of PD induced by chronic low doses of MPTP is capable of reproducing the clinical intestinal pathology of PD, as well as whether gut microbial dysbiosis accompanies this pathology. C57BL/6 male mice were administered 18 mg/kg MPTP twice per week for 5 weeks via intraperitoneal injection. GI function was assessed by measuring the 1-h stool frequency and fecal water content; motor function was assessed by pole tests; and tyrosine hydroxylase and alpha-synuclein expression were analyzed. Furthermore, the inflammation, intestinal barrier and composition of the gut microbiota were measured. We found that MPTP caused GI dysfunction and intestinal pathology prior to motor dysfunction. The composition of the gut microbiota was changed; in particular, the change in the abundance of Lachnospiraceae, Erysipelotrichaceae, Prevotellaceae, Clostridiales, Erysipelotrichales and Proteobacteria was significant. These results indicate that a chronic low-dose MPTP model can be used to evaluate the progression of intestinal pathology and gut microbiota dysbiosis in the early stage of PD, which may provide new insights into the pathogenesis of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Disease Models, Animal; Enteric Nervous System; Gastrointestinal Diseases; Gastrointestinal Microbiome; Inflammation; Male; Mice, Inbred C57BL; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by the formation of α-synuclein-containing protein aggregates called Lewy bodies within the brain. A crucial role for α-synuclein in the pathogenesis of PD is also suggested by the fact that point mutations, increased copy number, or polymorphisms in the α-synuclein gene SNCA all cause or contribute to the development of PD. In addition to SNCA, an increasing number of other genes have been implicated in PD. While mutations in at least some of these genes have been shown to cause the formation of Lewy bodies, the role of α-synuclein in these genetic forms of PD remains poorly defined. Since C. elegans do not have a homolog of α-synuclein, this organism provides the opportunity to identify synergism between α-synuclein and other genes implicated in PD. To do this, we generated a novel C. elegans model in which wild-type α-synuclein is ubiquitously expressed from a single copy transgene, and examined the resulting effect on phenotypic deficits in PD deletion mutants affecting PARK2/pdr-1, PINK1/pink-1, DJ-1/djr-1.1 and ATP13A2/catp-6. While the PD deletion mutants exhibit only mild phenotypic deficits in absence of α-synuclein, expression of wild-type α-synuclein caused increased sensitivity to multiple stresses, induced deficits in dopamine-dependent behavior, and accelerated loss of dopamine neurons. Overall, these results suggest that the recessive loss of function mutations act together with α-synuclein to cause PD, and that α-synuclein lowering strategies may be effective in genetic forms of PD.

Topics: Age Factors; alpha-Synuclein; Animals; Animals, Genetically Modified; Behavioral Symptoms; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Gene Dosage; Gene Expression Regulation; Humans; Luminescent Proteins; Mice; Muscle, Skeletal; Neurons; Oxidative Stress; Parkinson Disease; Physical Stimulation; Protein Kinases; Proton-Translocating ATPases; Ubiquitin-Protein Ligases

α-Synuclein (α-Syn)-induced neuroinflammation plays a crucial role in the pathogenesis of Parkinson's disease (PD). Dopamine D2 receptor (Drd2) has been regarded as a potential anti-inflammatory target in the therapy of neurodegenerative diseases. However, the effect of astrocytic Drd2 in α-Syn-induced neuroinflammation remains unclear.. The effect of Drd2 on neuroinflammation was examined in mouse primary astrocyte in vitro and A53T transgenic mice in vivo. The inflammatory responses of astrocyte were detected using immunofluorescence, ELISA, and qRT-PCR. The details of molecular mechanism were assessed using Western blotting and protein-protein interaction assays.. We showed that the selective Drd2 agonist quinpirole suppressed inflammation in the midbrain of wild-type mice, but not in α-Syn-overexpressed mice. We also found that Drd2 agonists significantly alleviated LPS-induced inflammatory response in astrocytes, but failed to suppress α-Syn-induced inflammatory response. The anti-inflammation effect of Drd2 was dependent on β-arrestin2-mediated signaling, but not classical G protein pathway. α-Syn reduced the expression of β-arrestin2 in astrocytes. Increased the β-arrestin2 expression restored in the anti-inflammation of Drd2 in α-Syn-induced inflammation. Furthermore, we demonstrated that α-Syn disrupted the anti-inflammation of Drd2 via inhibiting the association of β-arrestin2 with transforming growth factor-beta-activated kinase 1 (TAK1)-binding protein 1 (TAB1) and promoting TAK1-TAB1 interaction in astrocytes.. Our study illustrates that astrocytic Drd2 inhibits neuroinflammation through a β-arrestin2-dependent mechanism and provides a new strategy for treatment of PD. Our findings also reveal that α-Syn disrupts the function of β-arrestin2 and inflammatory pathways in the pathogenesis of PD.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Animals; Animals, Newborn; Astrocytes; beta-Arrestin 2; Cells, Cultured; Disease Models, Animal; Dopamine Agonists; Embryo, Mammalian; Gene Expression Regulation; Mice; Mice, Inbred C57BL; Mice, Transgenic; MPTP Poisoning; Mutation; Neurons; Protein Binding; Quinpirole; Receptors, Dopamine D2; Signal Transduction; Tyrosine 3-Monooxygenase

α-Synuclein (αS) regulates vesicle exocytosis but forms insoluble deposits in Parkinson's disease (PD). Developing disease-modifying therapies requires animal models that reproduce cardinal features of PD. We recently described a previously unrecognized physiological form of αS, α-helical tetramers, and showed that familial PD-causing missense mutations shift tetramers to aggregation-prone monomers. Here, we generated mice expressing the fPD E46K mutation plus 2 homologous E→K mutations in adjacent KTKEGV motifs. This tetramer-abrogating mutant causes phenotypes similar to PD. αS monomers accumulate at membranes and form vesicle-rich inclusions. αS becomes insoluble, proteinase K-resistant, Ser129-phosphorylated, and C-terminally truncated, as in PD. These changes affect regions controlling motor behavior, including a decrease in nigrostriatal dopaminergic neurons. The outcome is a progressive motor syndrome including tremor and gait and limb deficits partially responsive to L-DOPA. This fully penetrant phenotype indicates that tetramers are required for normal αS homeostasis and that chronically shifting tetramers to monomers may result in PD, with attendant therapeutic implications.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Brain; Disease Models, Animal; Levodopa; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation, Missense; Neurons; Parkinsonian Disorders; Protein Conformation

This report demonstrates insoluble alpha-synuclein (aSYN)+ aggregates in human sporadic Parkinson's disease (PD) midbrain that are linearly correlated with loss of glucocerebrosidase (GCase) activity. To identify early protein-lipid interactions that coincide with loss of lipid homeostasis, an aging study was carried out in mice with age-dependent reductions in GCase function. The analysis identified aberrant lipid-association by aSYN and hyperphosphorylated Tau (pTau) in a specific subset of neurotransmitter-containing, Secretogranin II (SgII)+ large, dense-core vesicles (LDCVs) responsible for neurotransmission of dopamine and other monoamines. The lipid vesicle-accumulation was concurrent with loss of PSD-95 suggesting synaptic destabilization. aSYN overexpression in the absence of lipid deregulation did not recapitulate the abnormal association with SgII+ vesicles. These results show lipid-dependent changes occur with age in neuronal vesicular membrane compartments that accumulate lipid-stabilized aSYN and pTau.

Topics: alpha-Synuclein; Animals; Case-Control Studies; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Glucosylceramidase; Humans; Lipids; Male; Mice; Neurons; Neurotransmitter Agents; Parkinson Disease; Secretogranin II; tau Proteins

Amyloid-β (Aβ) peptide and α-synuclein (α-syn) are major components of senile plaques in Alzheimer's disease (AD) and Lewy bodies in Parkinson's disease (PD), respectively. Co-occurrence of Aβ and α-syn in the senile brains of AD and LB diseases suggests interactions between the two proteins. However, the significance of the overlapping deposition, especially the effects of α-syn on the Aβ aggregation, still remains to be clarified. In the present study, we investigated the effects of α-syn pre-formed fibrils (PFFs) injection on the cognitive behaviors and Aβ deposition in the brain of APP/PS1 transgenic AD mice by using Morris water maze (MWM) test, immunohistochemistry and western blot techniques. We found that APP/PS1 transgenic mice exhibited an obvious elevation in the α-syn load, as well as Aβ deposition in the brain compared with wild type of C57 BL littermates. 5 months after cerebral injection of exogenous α-syn, MWM tests showed an alleviation in cognitive impairments in APP/PS1 mice; western blot and immunohistochemistry experiments also exhibited a significant reduction in Aβ level in the brain of APP/PS1 mice injected with α-syn. These results suggest that α-syn aggregated in the brain of AD may act as a protective factor and defend the brain tissue from early Aβ deposition and cognitive deficits.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Cognition Disorders; Cognitive Dysfunction; Disease Models, Animal; Humans; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred C57BL; Mice, Transgenic; Plaque, Amyloid; Presenilin-1; Protein Aggregation, Pathological; Spatial Memory

Parkinson's disease (PD) is characterized by a profound loss of dopaminergic neurons in the substantia nigra, accompanied by chronic neuroinflammation, mitochondrial dysfunction, and widespread accumulation of α-synuclein-rich protein aggregates in the form of Lewy bodies. However, the mechanisms linking α-synuclein pathology and dopaminergic neuronal death to chronic microglial neuroinflammation have not been completely elucidated. We show that activation of the microglial NLR family pyrin domain containing 3 (NLRP3) inflammasome is a common pathway triggered by both fibrillar α-synuclein and dopaminergic degeneration in the absence of α-synuclein aggregates. Cleaved caspase-1 and the inflammasome adaptor protein apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) were elevated in the substantia nigra of the brains of patients with PD and in multiple preclinical PD models. NLRP3 activation by fibrillar α-synuclein in mouse microglia resulted in a delayed but robust activation of the NLRP3 inflammasome leading to extracellular interleukin-1β and ASC release in the absence of pyroptosis. Nanomolar doses of a small-molecule NLRP3 inhibitor, MCC950, abolished fibrillar α-synuclein-mediated inflammasome activation in mouse microglial cells and extracellular ASC release. Furthermore, oral administration of MCC950 in multiple rodent PD models inhibited inflammasome activation and effectively mitigated motor deficits, nigrostriatal dopaminergic degeneration, and accumulation of α-synuclein aggregates. These findings suggest that microglial NLRP3 may be a sustained source of neuroinflammation that could drive progressive dopaminergic neuropathology and highlight NLRP3 as a potential target for disease-modifying treatments for PD.

Topics: Administration, Oral; alpha-Synuclein; Animals; CARD Signaling Adaptor Proteins; Disease Models, Animal; Dopaminergic Neurons; Extracellular Space; Furans; Heterocyclic Compounds, 4 or More Rings; Humans; Indenes; Inflammasomes; Mice; Microglia; Nerve Degeneration; NLR Family, Pyrin Domain-Containing 3 Protein; Parkinson Disease; Protein Aggregates; Pyroptosis; Substantia Nigra; Sulfonamides; Sulfones

Accumulation of alpha-synuclein (ASYN) in neurons and other CNS cell types may contribute to the underlying pathology of synucleinopathies including Parkinson's disease (PD), dementia with Lewy bodies (DLB) and Multiple Systems Atrophy (MSA). In support of this hypothesis for PD, ASYN immunopositive aggregates are a prominent pathological feature of PD, and mutations and gene multiplications of human wild type (WT) ASYN cause rare familial autosomal-dominant forms of PD. Targeted therapeutics that reduce the accumulation of ASYN could prevent or slow the neurodegenerative processes in PD and other synucleinopathies. NPT200-11 is a novel small molecule inhibitor of ASYN misfolding and aggregation. The effects of NPT200-11 on ASYN neuropathology were evaluated in animal models over expressing human alpha synuclein. Longitudinal studies using retinal imaging in mice expressing a hASYN::GFP fusion protein revealed that 2 months of once daily administration of NPT200-11 (5 mg/kg IP) resulted in a time-dependent and progressive reduction in retinal ASYN pathology. The effects of NPT200-11 on ASYN pathology in cerebral cortex and on other disease-relevant endpoints was evaluated in the Line 61 transgenic mouse model overexpressing human wild type ASYN. Results from these studies demonstrated that NPT200-11 reduced alpha-synuclein pathology in cortex, reduced associated neuroinflammation (astrogliosis), normalized striatal levels of the dopamine transporter (DAT) and improved motor function. To gain insight into the relationship between dose, exposure, and therapeutic benefit pharmacokinetic studies were also conducted in mice. These studies demonstrated that NPT200-11 is orally bioavailable and brain penetrating and established target plasma and brain exposures for future studies of potential therapeutic benefit.

Topics: alpha-Synuclein; Animals; Cerebral Cortex; Disease Models, Animal; Gene Expression Regulation; Humans; Inflammation; Lewy Body Disease; Mice; Mice, Transgenic; Multiple System Atrophy; Neurons; Parkinson Disease; Piperidines; Protein Aggregation, Pathological; Protein Folding; Pyrazines; Pyrimidines; Retina

Parkinson's disease (PD) is a neurodegenerative disorder characterized by Lewy pathology and progressive loss of dopaminergic neurons in the substantia nigra. Lewy pathology mainly consists of abnormal aggregates of α-synuclein, which play a pivotal role in PD pathophysiology. However, the complexity of PD leads to clinical challenges, and there are still no treatments to halt or slow the neurodegenerative process. Resveratrol (RV) is a natural polyphenol compound with multiple biological activities, which has been reported to exert neuroprotective effects on several neurological diseases. Here we first provided evidence that RV treatment alleviated motor and cognitive deficits in the A53T α-synuclein mouse model of PD in a dose-dependent manner. The beneficial effects of RV against PD resulted from inhibiting α-synuclein aggregation and cytotoxicity, lowering the levels of total α-synuclein and oligomers, reducing neuroinflammation and oxidative stress. These findings suggest that RV has promising therapeutic potential for PD and other synucleinopathies.

Topics: alpha-Synuclein; Animals; Cognition; Disease Models, Animal; Humans; Male; Mice; Mice, Transgenic; Motor Activity; Mutation, Missense; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Resveratrol

The progressive loss of midbrain (MB) dopaminergic (DA) neurons defines the motor features of Parkinson disease (PD), and modulation of risk by common variants in PD has been well established through genome-wide association studies (GWASs). We acquired open chromatin signatures of purified embryonic mouse MB DA neurons because we anticipated that a fraction of PD-associated genetic variation might mediate the variants' effects within this neuronal population. Correlation with >2,300 putative enhancers assayed in mice revealed enrichment for MB cis-regulatory elements (CREs), and these data were reinforced by transgenic analyses of six additional sequences in zebrafish and mice. One CRE, within intron 4 of the familial PD gene SNCA, directed reporter expression in catecholaminergic neurons from transgenic mice and zebrafish. Sequencing of this CRE in 986 individuals with PD and 992 controls revealed two common variants associated with elevated PD risk. To assess potential mechanisms of action, we screened >16,000 proteins for DNA binding capacity and identified a subset whose binding is impacted by these enhancer variants. Additional genotyping across the SNCA locus identified a single PD-associated haplotype, containing the minor alleles of both of the aforementioned PD-risk variants. Our work posits a model for how common variation at SNCA might modulate PD risk and highlights the value of cell-context-dependent guided searches for functional non-coding variation.

Topics: Adult; Aged; Aged, 80 and over; Alleles; alpha-Synuclein; Animals; Chromatin; Disease Models, Animal; Dopaminergic Neurons; Enhancer Elements, Genetic; Female; Genetic Predisposition to Disease; Genotype; Humans; Introns; Male; Mice; Mice, Transgenic; Middle Aged; Parkinson Disease; Pregnancy; Zebrafish

Commonalities and, in some cases, pathological overlap between neurodegenerative diseases have led to speculation that targeting of underlying mechanisms might be of potentially shared therapeutic benefit. Alzheimer's disease is characterized by the formation of plaques, composed primarily of the amyloid-β 1-42 (Aβ) peptide in the brain, resulting in neurodegeneration. Previously, we have shown that overexpression of the lysosomal-trafficking protein, human Vps41 (hVps41), is neuroprotective in a transgenic worm model of Parkinson's disease, wherein progressive dopaminergic neurodegeneration is induced by α-synuclein overexpression. Here, we report the results of a systematic comparison of hVps41-mediated neuroprotection between α-synuclein and Aβ in transgenic nematode models of Caenorhabditis elegans. Our results indicate that an ARF-like GTPase gene product, ARL-8, mitigates endocytic Aβ neurodegeneration in a VPS-41-dependent manner, rather than through RAB-7 and AP3 as with α-synuclein. Furthermore, the neuroprotective effect of ARL-8 or hVps41 appears to be dependent on their colocalization and the activity of ARL-8. Additionally, we demonstrate that the LC3 orthologue, LGG-2, plays a critical role in Aβ toxicity with ARL-8. Further analysis of functional effectors of Aβ protein processing via the lysosomal pathway will assist in the elucidation of the underlying mechanism involving VPS-41-mediated neuroprotection. These results reveal functional distinctions in the intracellular management of neurotoxic proteins that serve to better inform the path for development of therapeutic interventions to halt neurodegeneration.

Topics: ADP-Ribosylation Factors; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopamine; Gene Expression Regulation; Humans; Membrane Proteins; Microtubule-Associated Proteins; Nerve Degeneration; Neuroprotection; Parkinson Disease; Peptide Fragments; Vesicular Transport Proteins

Hyperphosphorylated α-synuclein in Lewy bodies and Lewy neurites is a characteristic neuropathological feature of Parkinson's disease (PD) and Dementia with Lewy bodies (DLB). The catalytic subunit of the specific phosphatase, protein phosphatase 2A (PP2A) that dephosphorylates α-synuclein, is hypomethylated in these brains, thereby impeding the assembly of the active trimeric holoenzyme and reducing phosphatase activity. This phosphatase deficiency contributes to the accumulation of hyperphosphorylated α-synuclein, which tends to fibrillize more than unmodified α-synuclein. Eicosanoyl-5-hydroxytryptamide (EHT), a fatty acid derivative of serotonin found in coffee, inhibits the PP2A methylesterase so as to maintain PP2A in a highly active methylated state and mitigates the phenotype of α-synuclein transgenic (Syn

Topics: alpha-Synuclein; Animals; Brain; Caffeine; Coffee; Disease Models, Animal; Fatty Acids; Lewy Body Disease; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Neuroprotection; Parkinson Disease; Phosphorylation; Protein Phosphatase 2; Serotonin

Parkinson's disease (PD) and multiple system atrophy (MSA) are neurodegenerative diseases characterized by inclusions mainly composed of α-synuclein (α-syn) aggregates. The objective of this study was to investigate if β-synuclein (β-syn) overexpression could have beneficial effects by inhibiting the aggregation of α-syn. The M83 transgenic mouse is a model of synucleinopathy, which develops severe motor symptoms associated with aggregation of α-syn. M83 neonate or adult mice were injected with adeno-associated virus vectors carrying the human β-syn gene (AAVβ-syn) or green fluorescent protein gene (AAVGFP) using different injection sites. The M83 disease was - or not - accelerated using extracts of M83 brains injected with brain extract from mouse (M83) or human (MSA) origins. AAV vectors expression was confirmed using Western blot and ELISA technics. AAV mediated β-syn overexpression did not delay the disease onset or reduce the α-syn phosphorylated at serine 129 levels detected by ELISA, regardless of the AAV injection route and the inoculation of brain extracts. Instead, a proteinase-K resistant β-syn staining was detected by immunohistochemistry, specifically in sick M83 mice overexpressing β-syn after inoculation of AAVβ-syn. This study indicated for the first time that viral vector-mediated β-syn overexpression could form aggregates in a model of synucleinopathy.

Topics: alpha-Synuclein; Animals; beta-Synuclein; Dependovirus; Disease Models, Animal; Genetic Vectors; Mice; Mice, Transgenic; Multiple System Atrophy; Neuroprotection; Transduction, Genetic

α-synclein (αS) aggregation is a representative molecular feature of the pathogenesis of Parkinson's disease (PD). Epigallocatechin gallate (EGCG) can prevent αS aggregation

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Catechin; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Drug Carriers; Humans; Membrane Proteins; Mice; Molecular Targeted Therapy; Nanoparticles; Neuroprotective Agents; Parkinson Disease; Protein Aggregation, Pathological; Treatment Outcome

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are neurodegenerative disorders of the aging population characterized by the accumulation of α-synuclein (α-syn). The mechanisms triggering α-syn toxicity are not completely understood, however, c-terminus truncation of α-syn by proteases such as calpain may have a role. Therefore, inhibition of calpain may be of value. The main objective of this study was to evaluate the effects of systemically administered novel low molecular weight calpain inhibitors on α-syn pathology in a transgenic mouse model. For this purpose, non-tg and α-syn tg mice received the calpain inhibitors - Gabadur, Neurodur or a vehicle, twice a day for 30 days. Immunocytochemical analysis showed a 60% reduction in α-syn deposition using Gabadur and a 40% reduction using Neurodur with a concomitant reduction in c-terminus α-syn and improvements in neurodegeneration. Western blot analysis showed a 77% decrease in α-spectrin breakdown products (SBDPs) SBDPs with Gabadur and 63% reduction using Neurodur. There was a 65% reduction in the active calpain form with Gabadur and a 45% reduction with Neurodur. Moreover, treatment with calpain inhibitors improved activity performance of the α-syn tg mice. Taken together, this study suggests that calpain inhibition might be considered in the treatment of synucleinopathies.

Topics: alpha-Synuclein; Animals; Astrocytes; Calpain; Disease Models, Animal; Glycoproteins; Immunohistochemistry; Lewy Body Disease; Mice; Mice, Transgenic; Neuroglia; Neurons; Parkinson Disease

Parkinson's disease (PD) is associated with aggregation of α-synuclein and selective death of dopaminergic (DA) neurons in the substantia nigra, thereby leading to cognitive and motor impairments. Nowadays, the drugs commonly used for PD treatment, such as levodopa, provide only symptomatic relief. Therefore, seeking new drugs against PD, especially from plants and marine organisms, is one of the major research areas to be explored. This study aimed to investigate the anti-Parkinson activity of the extracts from the sea cucumber, Holothuria scabra, by using Caenorhabditis elegans as a model.. H. scabra was solvent-extracted and subdivided into six fractions including whole body-ethyl acetate (WBEA), body wall-ethyl acetate (BWEA), viscera-ethyl acetate (VIEA), whole body-butanol (WBBU), body wall-butanol (BWBU), and viscera-butanol (VIBU). The extracts were tested in C. elegans BZ555 strain expressing the green fluorescent protein (GFP) specifically in the DA neurons and NL5901 strain expressing human α-synuclein in the muscle cells.. WBEA, BWEA, and WBBU fractions of H. scabra extracts at 500 µg/ml significantly attenuated DA neuron-degeneration induced by selective cathecholamine neurotoxin 6-hydroxydopamine (6-OHDA) in the BZ555 strain. Moreover, the extracts also reduced α-synuclein aggregation and restored lipid content in NL5901, as well as improved food-sensing behavior and prolonged lifespan in the 6-OHDA-treated wild-type strain.. The study indicated that the H. scabra extracts have anti-Parkinson potential in the C. elegans model. These findings encourage further investigations on using the H. scabra extract, as well as its active constituent compounds, as a possible preventive and/or therapeutic intervention against PD.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Biological Products; Caenorhabditis elegans; Disease Models, Animal; Dopaminergic Neurons; Holothuria; Nerve Degeneration; Neuroprotective Agents; Oxidopamine; Parkinson Disease

The term "motor neuron disease" encompasses a spectrum of disorders in which motor neurons are the primary pathological target. However, in both patients and animal models of these diseases, not all motor neurons are equally vulnerable, in that while some motor neurons are lost very early in disease, others remain comparatively intact, even at late stages. This creates a valuable system to investigate the factors that regulate motor neuron vulnerability. In this study, we aim to use this experimental paradigm to identify potential transcriptional modifiers. We have compared the transcriptome of motor neurons from healthy wild-type mice, which are differentially vulnerable in the childhood motor neuron disease Spinal Muscular Atrophy (SMA), and have identified 910 transcriptional changes. We have compared this data set with published microarray data sets on other differentially vulnerable motor neurons. These neurons were differentially vulnerable in the adult onset motor neuron disease Amyotrophic Lateral Sclerosis (ALS), but the screen was performed on the equivalent population of neurons from neurologically normal human, rat and mouse. This cross species comparison has generated a refined list of differentially expressed genes, including CELF5, Col5a2, PGEMN1, SNCA, Stmn1 and HOXa5, alongside a further enrichment for synaptic and axonal transcripts. As an in vivo validation, we demonstrate that the manipulation of a significant number of these transcripts can modify the neurodegenerative phenotype observed in a Drosophila line carrying an ALS causing mutation. Finally, we demonstrate that vector-mediated expression of alpha-synuclein (SNCA), a transcript decreased in selectively vulnerable motor neurons in all four screens, can extend life span, increase weight and decrease neuromuscular junction pathology in a mouse model of SMA. In summary, we have combined multiple data sets to identify transcripts, which are strong candidates for being phenotypic modifiers, and demonstrated SNCA is a modifier of pathology in motor neuron disease.

Topics: alpha-Synuclein; Amyotrophic Lateral Sclerosis; Animals; Axons; Disease Models, Animal; Drosophila melanogaster; Gene Expression Regulation; Humans; Mice; Motor Neuron Disease; Motor Neurons; Muscle, Skeletal; Neuromuscular Junction; Phenotype; Rats; Transcriptome

Parkinson's disease (PD) is a neurodegenerative disorder characterised by progressive motor symptoms resulting from chronic loss of dopaminergic neurons in the nigrostriatal pathway. The over expression of the protein alpha-synuclein in the substantia nigra has been used to induce progressive dopaminergic neuronal loss and to reproduce key histopathological and temporal features of PD in animal models. However, the neurophysiological aspects of the alpha-synuclein PD model have been poorly characterised. Hereby, we performed chronic in vivo electrophysiological recordings in the corticostriatal circuit of rats injected with viral vector to over express alpha-synuclein in the right substantia nigra. Our model, previously shown to exhibit mild motor deficits, presented moderate dopaminergic cell loss but did not present prominent local field potential oscillations in the beta frequency range (11-30 Hz), considered a hallmark of PD, during the 9 weeks after onset of alpha-synuclein over expression. Spinal cord stimulation, a potential PD symptomatic therapy, was applied regularly from sixth to ninth week after alpha-synuclein over expression onset and had an inhibitory effect on the firing rate of corticostriatal neurons in both control and alpha-synuclein hemispheres. Dopamine synthesis inhibition at the end of the experiment resulted in severe parkinsonian symptoms such as akinesia and increased beta and high-frequency (>90 Hz) oscillations. These results suggest that the alpha-synuclein PD model with moderate level of dopaminergic depletion does not reproduce the prominent corticostriatal beta oscillatory activity associated to parkinsonian conditions.

Topics: alpha-Synuclein; Animals; Beta Rhythm; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Locomotion; Male; Parkinson Disease; Rats; Rats, Sprague-Dawley; Spinal Cord; Substantia Nigra

Neurodegenerative diseases are characterized by the degeneration of specific brain areas associated with accumulation of disease-related protein in extra- or intra-cellular deposits. Their preclinical investigations are mostly based on genetically-engineered animals. Despite their interest, these models are often based on high level of disease-related protein expression, thus questioning their relevance to human pathology and calling for the alternate use of ecological models. In the past few years, Octodon degus has emerged as a promising animal model displaying age-dependent Alzheimer's disease-related pathology. As neurodegenerative-related proteins often co-deposit in the brain of patients, we assessed the occurrence of α-synuclein-related pathology in this model using state-of-the-art immunohistochemistry and biochemistry. Despite our efforts and in contrast with previously published results, our study argues against the use of Octodon degus as a suitable natural model of neurodegenerative disorder as we failed to identify either Parkinson's disease- or Alzheimer's disease-related brain pathologies.

Topics: Aging; alpha-Synuclein; Alzheimer Disease; Animals; Brain; Disease Models, Animal; Octodon; Parkinson Disease

α-Synuclein misfolding and aggregation is a hallmark in Parkinson's disease and in several other neurodegenerative diseases known as synucleinopathies. The toxic properties of α-synuclein are conserved from yeast to man, but the precise underpinnings of the cellular pathologies associated are still elusive, complicating the development of effective therapeutic strategies. Combining molecular genetics with target-based approaches, we established that glycation, an unavoidable age-associated post-translational modification, enhanced α-synuclein toxicity in vitro and in vivo, in Drosophila and in mice. Glycation affected primarily the N-terminal region of α-synuclein, reducing membrane binding, impaired the clearance of α-synuclein, and promoted the accumulation of toxic oligomers that impaired neuronal synaptic transmission. Strikingly, using glycation inhibitors, we demonstrated that normal clearance of α-synuclein was re-established, aggregation was reduced, and motor phenotypes in Drosophila were alleviated. Altogether, our study demonstrates glycation constitutes a novel drug target that can be explored in synucleinopathies as well as in other neurodegenerative conditions.

Topics: Aging; alpha-Synuclein; Animals; Cell Differentiation; Cell Survival; Cells, Cultured; Disease Models, Animal; Drosophila; Enzyme Inhibitors; Female; Glycosylation; Hippocampus; Humans; Induced Pluripotent Stem Cells; Male; Mice; Mice, Transgenic; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Processing, Post-Translational; Pyruvaldehyde; Rats; Yeasts

Clinical studies report significant increases in acrolein (an α,β-unsaturated aldehyde) in the substantia nigra (SN) of patients with Parkinson's disease (PD). In the present study, acrolein-induced neurotoxicity in the nigrostriatal dopaminergic system was investigated by local infusion of acrolein (15, 50, 150 nmoles/0.5 μl) in the SN of Sprague-Dawley rats. Acrolein-induced neurodegeneration of nigrostriatal dopaminergic system was delineated by reductions in tyrosine hydroxylase (TH) levels, dopamine transporter levels and TH-positive neurons in the infused SN as well as in striatal dopamine content. At the same time, apomorphine-induced turning behavior was evident in rats subjected to a unilateral infusion of acrolein in SN. Acrolein was pro-oxidative by increasing 4-hydroxy-2-nonenal and heme oxygenase-1 levels. Furthermore, acrolein conjugated with proteins at lysine residue and induced α-synuclein aggregation in the infused SN. Acrolein was pro-inflammatory by activating astrocytes and microglia. In addition, acrolein activated caspase 1 in the infused SN, suggesting acrolein-induced inflammasome formation. The neurotoxic mechanisms underlying acrolein-induced neurotoxicity involved programmed cell death, including apoptosis and necroptosis. Compared with well-known Parkinsonian neurotoxins, including 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and rotenone which do not exist in the SN of PD patients, our in vivo study shows that acrolein acts as a Parkinsonian neurotoxin in the nigrostriatal dopaminergic system of rat brain.

Topics: Acrolein; alpha-Synuclein; Animals; Cell Death; Disease Models, Animal; Dopaminergic Neurons; Encephalitis; Male; Oxidative Stress; Parkinsonian Disorders; Protein Aggregation, Pathological; Rats, Sprague-Dawley; Substantia Nigra

Mouse embryonic stem cell (mESC) lines were derived by crossing heterozygous transgenic (tg) mice expressing green fluorescent protein (GFP) under the control of the rat tyrosine hydroxylase (TH) promoter, with homozygous alpha-synuclein (aSYN) mice expressing human mutant SNCA

Topics: alpha-Synuclein; Animals; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Genes, Reporter; Genotype; Humans; Mice; Mice, Transgenic; Mouse Embryonic Stem Cells; Parkinson Disease; Tyrosine 3-Monooxygenase

Mutations in the mitochondrial kinase PTEN-induced putative kinase 1 (PINK1) cause Parkinson's disease (PD), likely by disrupting PINK1's kinase activity. Although the mechanism(s) underlying how this loss of activity causes degeneration remains unclear, increasing PINK1 activity may therapeutically benefit some forms of PD. However, we must first learn whether restoring PINK1 function prevents degeneration in patients harboring PINK1 mutations, or whether boosting PINK1 function can offer protection in more common causes of PD. To test these hypotheses in preclinical rodent models of PD, we used kinetin triphosphate, a small-molecule that activates both wild-type and mutant forms of PINK1, which affects mitochondrial function and protects neural cells in culture. We chronically fed kinetin, the precursor of kinetin triphosphate, to PINK1-null rats in which PINK1 was reintroduced into their midbrain, and also to rodent models overexpressing α-synuclein. The highest tolerated dose of oral kinetin increased brain levels of kinetin for up to 6 months, without adversely affecting the survival of nigrostriatal dopamine neurons. However, there was no degeneration of midbrain dopamine neurons lacking PINK1, which precluded an assessment of neuroprotection and raised questions about the robustness of the PINK1 KO rat model of PD. In two rodent models of α-synuclein-induced toxicity, boosting PINK1 activity with oral kinetin provided no protective effects. Our results suggest that oral kinetin is unlikely to protect against α-synuclein toxicity, and thus fail to provide evidence that kinetin will protect in sporadic models of PD. Kinetin may protect in cases of PINK1 deficiency, but this possibility requires a more robust PINK1 KO model that can be validated by proof-of-principle genetic correction in adult animals.

Topics: Administration, Oral; alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Drug Administration Schedule; Humans; Kinetin; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Parkinson Disease; Protein Kinases; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Rodentia

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a highly effective symptomatic therapy for motor deficits in Parkinson's disease (PD). An additional, disease-modifying effect has been suspected from studies in toxin-based PD animal models, but these models do not reflect the molecular pathology and progressive nature of PD that would be required to evaluate a disease-modifying action. Defining a disease-modifying effect could radically change the way in which DBS is used in PD.. We applied STN-DBS in an adeno-associated virus (AAV) 1/2-driven human mutated A53T α-synuclein (aSyn)-overexpressing PD rat model (AAV1/2-A53T-aSyn). Rats were injected unilaterally, in the substantia nigra (SN), with AAV1/2-A53T-aSyn or control vector. Three weeks later, after behavioral and nigrostriatal dopaminergic deficits had developed, rats underwent STN-DBS electrode implantation ipsilateral to the vector-injected SN. Stimulation lasted for 3 weeks. Control groups remained OFF stimulation. Animals were sacrificed at 6 weeks.. Our data support the putative neuroprotective and disease-modifying effect of STN-DBS in a mechanistically relevant model of PD. Ann Neurol 2017;81:825-836.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Deep Brain Stimulation; Dependovirus; Disease Models, Animal; Genetic Vectors; Humans; Male; Mutation; Parkinson Disease; Rats; Rats, Sprague-Dawley; Subthalamic Nucleus

Parkinson's disease (PD) is an age-dependent neurodegenerative disease that can be caused by a variety of factors. Growing evidence shows that prior to the motor phase of PD can express molecular or imaging markers. Many long non-coding RNAs (lncRNAs) have been identified in neurodegenerative disease. However, the biogenesis and function of lncRNAs in the pre-symptomatic stage of PD is poorly understood. Here, we profiled the expression of lncRNAs and mRNAs in the substantia nigra pars compacta (SNpc) of pre-symptomatic mice over-expressing human A30P*A53T α-synuclein by microarray analysis. Based on the Pearson correlation analysis, lncRNA/mRNA co-expression network was constructed. GO enrichment and pathway analysis of lncRNAs-coexpressed mRNAs was conducted to identify the related biological function and pathologic pathways. Real-time PCR was used to detect the expression pattern of lncRNAs. Approximately 756 lncRNAs were aberrantly expressed in the SNpc of early over-expressing human A30P*A53T α-synuclein transgenic mice, including 477 downregulated lncRNAs and 279 upregulated lncRNAs. GO analysis indicated that these lncRNAs-coexpressed mRNAs were targeted to regulation of transcription (ontology: biological process), membrane (ontology: cellular component), and protein binding (ontology: molecular function). Pathway analysis indicated that lncRNAs-coexpressed mRNAs were mostly enriched in axon guidance signaling pathway. In conclusion, the present study firstly identified a series of novel early PD-associated lncRNAs caused by mutant α-synuclein. Further study the function of these aberrantly expressed lncRNAs may provide insight into treatment of early PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Gene Expression Profiling; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; RNA, Long Noncoding; Signal Transduction; Substantia Nigra

Disorders with progressive accumulation of α-synuclein (α-syn) are a common cause of dementia and parkinsonism in the aging population. Accumulation and propagation of α-syn play a role in the pathogenesis of these disorders. Previous studies have shown that immunization with antibodies that recognize C-terminus of α-syn reduces the intra-neuronal accumulation of α-syn and related deficits in transgenic models of synucleinopathy. These studies employed antibodies that recognize epitopes within monomeric and aggregated α-syn that were generated through active immunization or administered via passive immunization. However, it is possible that more specific effects might be achieved with antibodies recognizing selective species of the α-syn aggregates. In this respect we recently developed antibodies that differentially recognized various oligomers (Syn-O1, -O2, and -O4) and fibrilar (Syn-F1 and -F2) forms of α-syn. For this purpose wild-type α-syn transgenic (line 61) mice were immunized with these 5 different antibodies and neuropathologically and biochemically analyzed to determine which was most effective at reducing α-syn accumulation and related deficits. We found that Syn-O1, -O4 and -F1 antibodies were most effective at reducing accumulation of α-syn oligomers in multiple brain regions and at preventing neurodegeneration. Together this study supports the notion that selective antibodies against α-syn might be suitable for development new treatments for synucleinopathies such as PD and DLB.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Antibodies; Calcium-Binding Proteins; Cell Cycle; Cell Line, Tumor; Dementia; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Exploratory Behavior; Female; Glial Fibrillary Acidic Protein; Immunotherapy; Mice; Mice, Transgenic; Microfilament Proteins; Microscopy, Confocal; Neuroblastoma; Parkinsonian Disorders; Synaptophysin

Braak and Del Tredici have proposed that typical Parkinson disease (PD) has its origins in the olfactory bulb and gastrointestinal tract. However, the role of the olfactory system has insufficiently been explored in the pathogeneses of PD and Alzheimer disease (AD) in laboratory models. Here, we demonstrate applications of a new method to process mouse heads for microscopy by sectioning, mounting, and staining whole skulls ('holocranohistochemistry'). This technique permits the visualization of the olfactory system from the nasal cavity to mitral cells and dopamine-producing interneurons of glomeruli in the olfactory bulb. We applied this method to two specific goals: first, to visualize PD- and AD-linked gene expression in the olfactory system, where we detected abundant, endogenous α-synuclein and tau expression in the olfactory epithelium. Furthermore, we observed amyloid-β plaques and proteinase-K-resistant α-synuclein species, respectively, in cranial nerve-I of APP- and human SNCA-over-expressing mice. The second application of the technique was to the modeling of gene-environment interactions in the nasal cavity of mice. We tracked the infection of a neurotropic respiratory-enteric-orphan virus from the nose pad into cranial nerves-I (and -V) and monitored the ensuing brain infection. Given its abundance in the olfactory epithelia, we questioned whether α-synuclein played a role in innate host defenses to modify the outcome of infections. Indeed, Snca-null mice were more likely to succumb to viral encephalitis versus their wild-type littermates. Moreover, using a bacterial sepsis model, Snca-null mice were less able to control infection after intravenous inoculation with Salmonella typhimurium. Together, holocranohistochemistry enabled new discoveries related to α-synuclein expression and its function in mice. Future studies will address: the role of Mapt and mutant SNCA alleles in infection paradigms; the contribution of xenobiotics in the initiation of idiopathic PD; and the safety to the host when systemically targeting α-synuclein by immunotherapy.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Brain; Disease Models, Animal; Encephalitis, Viral; Female; Head; Humans; Immunohistochemistry; Male; Mammalian orthoreovirus 3; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Transgenic; Neural Pathways; Olfactory Mucosa; Olfactory Receptor Neurons; Reoviridae Infections; Salmonella Infections; Salmonella typhimurium; Tissue Preservation

Topics: Aged; Aged, 80 and over; Aging; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Brain; Cells, Cultured; Disease Models, Animal; Female; Humans; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Myelin Basic Protein; Myelin Sheath; Neurons; Parkinson Disease; Phospholipids; Presenilin-1

Parkinson's disease (PD) is characterized by progressive dopamine depletion and a loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Treadmill exercise is a promising non-pharmacological approach for reducing the risk of PD and other neuroinflammatory disorders, such as Alzheimer's disease. The goal of this study was to investigate the effects of treadmill exercise on α-synuclein-induced neuroinflammation and neuronal cell death in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Eight weeks of treadmill exercise improved motor deficits and reduced α-synuclein expression, a major causative factor of PD-like symptoms, in MPTP mice. Treadmill exercise also down-regulated the expression of toll-like receptor 2 and its associated downstream signaling molecules, including myeloid differentiation factor-88, tumor necrosis factor receptor-associated factor 6, and transforming growth factor-β-activated protein kinase 1. These effects were associated with reduced ionized calcium-binding adapter molecule 1 expression, decreased IκBα and nuclear transcription factor-κB phosphorylation, decreased tumor necrosis factor α and interleukin-1β expression, and decreased NADPH oxidase subunit expression in the SNpc and striatum. Additionally, it promoted the expression of tyrosine hydroxylase and the dopamine transporter, as well as plasma dopamine levels, in MPTP mice; these effects were associated with decreased caspase-3 expression and cleavage, as well as increased Bcl-2 expression in the SNpc. Taken together, our data suggest that treadmill exercise improves MPTP-associated motor deficits by exerting neuroprotective effects in the SNpc and striatum, supporting the notion that treadmill exercise is useful as a non-pharmacological tool for the management of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Male; Mice, Inbred C57BL; Myeloid Differentiation Factor 88; Neuroprotective Agents; NF-kappa B; Parkinson Disease; Physical Conditioning, Animal; Signal Transduction; Substantia Nigra; Toll-Like Receptor 2

Mounting evidence indicates that soluble oligomeric forms of amyloid proteins linked to neurodegenerative disorders, such as amyloid-β (Aβ), tau, or α-synuclein (αSyn) might be the major deleterious species for neuronal function in these diseases. Here, we found an abnormal accumulation of oligomeric αSyn species in AD brains by custom ELISA, size-exclusion chromatography, and nondenaturing/denaturing immunoblotting techniques. Importantly, the abundance of αSyn oligomers in human brain tissue correlated with cognitive impairment and reductions in synapsin expression. By overexpressing WT human αSyn in an AD mouse model, we artificially enhanced αSyn oligomerization. These bigenic mice displayed exacerbated Aβ-induced cognitive deficits and a selective decrease in synapsins. Following isolation of various soluble αSyn assemblies from transgenic mice, we found that in vitro delivery of exogenous oligomeric αSyn but not monomeric αSyn was causing a lowering in synapsin-I/II protein abundance. For a particular αSyn oligomer, these changes were either dependent or independent on endogenous αSyn expression. Finally, at a molecular level, the expression of synapsin genes

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Brain; Cognition; Cyclic AMP Response Element-Binding Protein; Disease Models, Animal; Genes, Tumor Suppressor; Humans; Memory Disorders; Mice; Mice, Transgenic; Nuclear Proteins; Nuclear Receptor Subfamily 4, Group A, Member 2; Protein Structure, Quaternary; Recombinant Proteins; Solubility; Synapsins

MSA is a fatal neurodegenerative disorder characterized by a combination of autonomic dysfunction, cerebellar ataxia, and l-dopa unresponsive parkinsonism. The hallmark of MSA is the accumulation of α-synuclein, forming cytoplasmic inclusions in oligodendrocytes. Adeno-associated viruses allow efficient targeting of disease-associated genes in selected cellular ensembles and have proven efficient for the neuronal overexpression of α-synuclein in the substantia nigra in the context of PD.. We aimed to develop viral-based models of MSA.. Chimeric viral vectors expressing either human wild-type α-synuclein or green fluorescent protein under the control of mouse myelin basic protein were injected in the striatum of rats and monkeys. Rats underwent a longitudinal motor assessment before histopathological analysis at 3 and 6 months.. Injection of vectors expressing α-synuclein in the striatum resulted in >80% oligodendroglial selectivity in rats and >60% in monkeys. Rats developed progressive motor deficits that were l-dopa unresponsive when assessed at 6 months. Significant loss of dopaminergic neurons occurred at 3 months, further progressing at 6 months, together with a loss of striatal neurons. Prominent α-synuclein accumulation, including phosphorylated and proteinase-K-resistant α-synuclein, was detected in the striatum and substantia nigra.. Viral-mediated oligodendroglial expression of α-synuclein allows replicating some of the key features of MSA. This flexible strategy can be used to investigate, in several species, how α-synuclein accumulation in selected oligodendroglial populations contributes to the pathophysiology of MSA and offers a new framework for preclinical validation of therapeutic strategies. © 2017 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Corpus Striatum; Dependovirus; Disease Models, Animal; Dopamine Agents; Gene Expression Regulation; Haplorhini; Humans; Levodopa; Male; Multiple System Atrophy; Myelin Basic Protein; Nerve Tissue Proteins; Oligodendroglia; Phosphorylation; Psychomotor Performance; Rats; Rats, Sprague-Dawley; Substantia Nigra

Cystatin C (CYS C, Cst3) is an endogenous cysteine protease inhibitor that plays neuroprotective roles in neurodegenerative diseases. We aimed to explore the association of CYS C with Parkinson's disease (PD) models and investigate its involvement in the role of neurovascular units (NVUs) in PD neuro-pathogenesis. We used A53T α-synuclein (SNCA) transgenic mice and 6-hydroxydopamine-lesioned DAergic PC12 cells as experimental PD models to investigate the mechanisms behind this association. The injections of CYS C were administered to the right substantia nigra (SN) of A53T SNCA transgenic mice to measure the effects of CYS C in transgenic A53T SNCA mice. To explore the angiogenesis in vivo and in vitro, we used the chick embryo chorioallantoic membrane (CAM) assay and tube formation (TF) assay. We found that CYS C has a neuroprotective effect in this in vivo PD model. We observed increased VEGF, NURR1 and autophagy markers LC3B and decreased SNCA and apoptosis marker cleaved CASP3 in different brain regions of CYS C-treated A53T SNCA transgenic mice. In vitro, we observed that CYS C-induced VEGF, a secreted protein, attenuated 6-OHDA-lesioned DAergic PC12 cell degeneration by regulating p-PKC-α/p-ERK1/2-Nurr1 signaling and inducing autophagy. VEGF-mediated angiogenesis was markedly enhanced in the conditioned media of 6-OHDA-lesioned PC12 cells with CYS C-overexpression, whereas blockage of autophagy in CYS C-overexpressing PC12 cells significantly downregulated VEGF expression and the associated angiogenesis. Our data indicate that CYS C displays dual neuronal-vascular functions, promoting PC12 cell survival and angiogenesis via regulating the level of secreted VEGF in NVUs. Our study provides evidence that may aid in the development of an alternative approach for the treatment of PD through modulation of CYS C-mediated neuronal-vascular pathways.

Topics: alpha-Synuclein; Animals; Autophagy; Caspase 3; Chick Embryo; Chorioallantoic Membrane; Cystatin C; Disease Models, Animal; Gene Expression Regulation; Humans; Injections, Intraventricular; Mice; Mice, Transgenic; Microtubule-Associated Proteins; Neovascularization, Physiologic; Neurons; Neuroprotective Agents; Nuclear Receptor Subfamily 4, Group A, Member 2; Oxidopamine; Parkinson Disease; PC12 Cells; Rats; Signal Transduction; Substantia Nigra; Vascular Endothelial Growth Factor A

Proteinaceous inclusions in neurons, composed primarily of α-synuclein, define the pathology in several neurodegenerative disorders. Neurons can internalize α-synuclein fibrils that can seed new inclusions from endogenously expressed α-synuclein. The factors contributing to the spread of pathology and subsequent neurodegeneration are not fully understood, and different compositions and concentrations of fibrils have been used in different hosts. Here, we systematically vary the concentration and length of well-characterized α-synuclein fibrils and determine their relative ability to induce inclusions and neurodegeneration in different hosts (primary neurons, C57BL/6J and C3H/HeJ mice, and Sprague Dawley rats). Using dynamic-light scattering profiles and other measurements to determine fibril length and concentration, we find that femptomolar concentrations of fibrils are sufficient to induce robust inclusions in primary neurons. However, a narrow and non-linear dynamic range characterizes fibril-mediated inclusion induction in axons and the soma. In mice, the C3H/HeJ strain is more sensitive to fibril exposures than C57BL/6J counterparts, with more inclusions and dopaminergic neurodegeneration. In rats, injection of fibrils into the substantia nigra pars compacta (SNpc) results in similar inclusion spread and dopaminergic neurodegeneration as injection of the fibrils into the dorsal striatum, with prominent inclusion spread to the amygdala and several other brain areas. Inclusion spread, particularly from the SNpc to the striatum, positively correlates with dopaminergic neurodegeneration. These results define biophysical characteristics of α-synuclein fibrils that induce inclusions and neurodegeneration both in vitro and in vivo, and suggest that inclusion spread in the brain may be promoted by a loss of neurons.

Topics: Acetylcholinesterase; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Humans; Inclusion Bodies; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Neurons; Phosphopyruvate Hydratase; Rats; Rats, Sprague-Dawley; Substantia Nigra; tau Proteins; Tyrosine 3-Monooxygenase

The identification of a DNA variant in pyridoxal kinase (Pdxk) associated with increased risk to Parkinson disease (PD) gene led us to study the inhibition of this gene in the Dopa decarboxylase (Ddc)-expressing neurons of the well-studied model organism Drosophila melanogaster. The multitude of biological functions attributable to the vitamers catalysed by this kinase reveal an overabundance of possible links to PD, that include dopamine synthesis, antioxidant activity and mitochondrial function. Drosophila possesses a single homologue of Pdxk and we used RNA interference to inhibit the activity of this kinase in the Ddc-Gal4-expressing neurons. We further investigated any association between this enhanced disease risk gene with the established PD model induced by expression of α-synuclein in the same neurons. We relied on the pro-survival functions of Buffy, an anti-apoptotic Bcl-2 homologue, to rescue the Pdxk-induced phenotypes.. To drive the expression of Pdxk RNA interference in DA neurons of Drosophila, we used Ddc-Gal4 which drives expression in both dopaminergic and serotonergic neurons, to result in decreased longevity and compromised climbing ability, phenotypes that are strongly associated with Drosophila models of PD. The inhibition of Pdxk in the α-synuclein-induced Drosophila model of PD did not alter longevity and climbing ability of these flies. It has been previously shown that deficiency in vitamers lead to mitochondrial dysfunction and neuronal decay, therefore, co-expression of Pdxk-RNAi with the sole pro-survival Bcl-2 homologue Buffy in the Ddc-Gal4-expressing neurons, resulted in increased survival and a restored climbing ability. In a similar manner, when we inhibited Pdxk in the developing eye using GMR-Gal4, we found that there was a decrease in the number of ommatidia and the disruption of the ommatidial array was more pronounced. When Pdxk was inhibited with the α-synuclein-induced developmental eye defects, the eye phenotypes were unaltered. Interestingly co-expression with Buffy restored ommatidia number and decreased the severity of disruption of the ommatidial array.. Though Pdxk is not a confirmed Parkinson disease gene, the inhibition of this kinase recapitulated the PD-like symptoms of decreased lifespan and loss of locomotor function, possibly producing a new model of PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopa Decarboxylase; Drosophila; Drosophila Proteins; Evolution, Molecular; Locomotion; Longevity; Neurons; Parkinson Disease; Proto-Oncogene Proteins c-bcl-2; Pyridoxal Kinase; Species Specificity; Transcription Factors; Vitamin B 6; Vitamin B Complex

Multiple system atrophy (MSA) is a horrible and unrelenting neurodegenerative disorder with an uncertain etiology and pathophysiology. MSA is a unique proteinopathy in which alpha-synuclein (α-syn) accumulates preferentially in oligodendroglia rather than neurons. Glial cytoplasmic inclusions (GCIs) of α-syn are thought to elicit changes in oligodendrocyte function, such as reduced neurotrophic support and demyelination, leading to neurodegeneration. To date, only a murine model using one of three promoters exist to study this disease. We sought to develop novel rat and nonhuman primate (NHP) models of MSA by overexpressing α-syn in oligodendroglia using a novel oligotrophic adeno-associated virus (AAV) vector, Olig001. To establish tropism, rats received intrastriatal injections of Olig001 expressing GFP. Histological analysis showed widespread expression of GFP throughout the striatum and corpus callosum with >95% of GFP+ cells co-localizing with oligodendroglia and little to no expression in neurons or astrocytes. We next tested the efficacy of this vector in rhesus macaques with intrastriatal injections of Olig001 expressing GFP. As in rats, we observed a large number of GFP+ cells in gray matter and white matter tracts of the striatum and the corpus callosum, with 90-94% of GFP+ cells co-localizing with an oligodendroglial marker. To evaluate the potential of our vector to elicit MSA-like pathology in NHPs, we injected rhesus macaques intrastriatally with Olig001 expressing the α-syn transgene. Histological analysis 3-months after injection demonstrated widespread α-syn expression throughout the striatum as determined by LB509 and phosphorylated serine-129 α-syn immunoreactivity, all of which displayed as tropism similar to that seen with GFP. As in MSA, Olig001-α-syn GCIs in our model were resistant to proteinase K digestion and caused microglial activation. Critically, demyelination was observed in the white matter tracts of the corpus callosum and striatum of Olig001-α-syn but not Olig001-GFP injected animals, similar to the human disease. These data support the concept that this vector can provide novel rodent and nonhuman primate models of MSA.

Topics: alpha-Synuclein; Animals; Astrocytes; Brain; Dependovirus; Disease Models, Animal; Endopeptidase K; Female; Genetic Vectors; Green Fluorescent Proteins; HEK293 Cells; Humans; Macaca mulatta; Male; Microglia; Multiple System Atrophy; Neurons; Oligodendroglia; Rats, Sprague-Dawley

Recent studies have demonstrated that hyperphosphorylation of tau protein plays a role in neuronal toxicities of α-synuclein (ASYN) in neurodegenerative disease such as familial Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and Parkinson's disease. Using a transgenic mouse model of Parkinson's disease (PD) that expresses GFP-ASYN driven by the PDGF-β promoter, we investigated how accumulation of ASYN impacted axonal function. We found that retrograde axonal trafficking of brain-derived neurotrophic factor (BDNF) in DIV7 cultures of E18 cortical neurons was markedly impaired at the embryonic stage, even though hyperphosphorylation of tau was not detectable in these neurons at this stage. Interestingly, we found that overexpressed ASYN interacted with dynein and induced a significant increase in the activated levels of small Rab GTPases such as Rab5 and Rab7, both key regulators of endocytic processes. Furthermore, expression of ASYN resulted in neuronal atrophy in DIV7 cortical cultures of either from E18 transgenic mouse model or from rat E18 embryos that were transiently transfected with ASYN-GFP for 72 hrs. Our studies suggest that excessive ASYN likely alters endocytic pathways leading to axonal dysfunction in embryonic cortical neurons in PD mouse models.

Topics: alpha-Synuclein; Animals; Axons; Brain-Derived Neurotrophic Factor; Disease Models, Animal; Gene Expression; Genes, Reporter; Mice; Mice, Transgenic; Molecular Imaging; Neurons; Parkinson Disease; Protein Transport; rab5 GTP-Binding Proteins; Signal Transduction; Synucleins

Abnormal accumulation of alpha-synuclein (αsyn) is a pathological hallmark of Lewy body related disorders such as Parkinson's disease and Dementia with Lewy body disease. During the past two decades, a myriad of animal models have been developed to mimic pathological features of synucleinopathies by over-expressing human αsyn. Although different strategies have been used, most models have little or no reliable and predictive phenotype. Novel animal models are a valuable tool for understanding neuronal pathology and to facilitate development of new therapeutics for these diseases. Here, we report the development and characterization of a novel model in which mice rapidly express wild-type αsyn via somatic brain transgenesis mediated by adeno-associated virus (AAV). At 1, 3, and 6 months of age following intracerebroventricular (ICV) injection, mice were subjected to a battery of behavioral tests followed by pathological analyses of the brains. Remarkably, significant levels of αsyn expression are detected throughout the brain as early as 1 month old, including olfactory bulb, hippocampus, thalamic regions and midbrain. Immunostaining with a phospho-αsyn (pS129) specific antibody reveals abundant pS129 expression in specific regions. Also, pathologic αsyn is detected using the disease specific antibody 5G4. However, this model did not recapitulate behavioral phenotypes characteristic of rodent models of synucleinopathies. In fact no deficits in motor function or cognition were observed at 3 or 6 months of age. Taken together, these findings show that transduction of neonatal mouse with AAV-αsyn can successfully lead to rapid, whole brain transduction of wild-type human αsyn, but increased levels of wildtype αsyn do not induce behavior changes at an early time point (6 months), despite pathological changes in several neurons populations as early as 1 month.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Astrocytes; Brain; Dependovirus; Disease Models, Animal; Genetic Vectors; Gliosis; HEK293 Cells; Humans; Learning; Memory; Mice, Inbred C57BL; Microglia; Motor Activity; Neurodegenerative Diseases

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model remains the most commonly used animal model of Parkinson's disease (PD). There are three MPTP-treatment schemes: acute, subacute and chronic. Considering the advantages of the period and similarity to PD, the subacute model was often chosen to assess the validity of new candidates, but the changes caused by the subacute MPTP treatment and the appropriate positive control for this model remain to be further confirmed. The aim of this study was: to estimate the value of the subacute MPTP mouse model in aspects of behavioral performance, biochemical changes and pathological abnormalities, and to find effective positive drugs. Male C57BL/6 mice were injected with MPTP (30 mg·kg

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antiparkinson Agents; Astrocytes; Behavior, Animal; Benserazide; Benzothiazoles; Blood-Brain Barrier; Chromatography, High Pressure Liquid; Corpus Striatum; Disease Models, Animal; Drug Combinations; Levodopa; Male; Mice; Mice, Inbred C57BL; Microscopy, Electron; Parkinsonian Disorders; Pramipexole; Selegiline

The accumulation of amyloidogenic proteins is a pathological hallmark of neurodegenerative disorders. The aberrant accumulation of the microtubule associating protein tau (MAPT, tau) into toxic oligomers and amyloid deposits is a primary pathology in tauopathies, the most common of which is Alzheimer's disease (AD). Intrinsically disordered proteins, like tau, are enriched with proline residues that regulate both secondary structure and aggregation propensity. The orientation of proline residues is regulated by cis/trans peptidyl-prolyl isomerases (PPIases). Here we show that cyclophilin 40 (CyP40), a PPIase, dissolves tau amyloids in vitro. Additionally, CyP40 ameliorated silver-positive and oligomeric tau species in a mouse model of tau accumulation, preserving neuronal health and cognition. Nuclear magnetic resonance (NMR) revealed that CyP40 interacts with tau at sites rich in proline residues. CyP40 was also able to interact with and disaggregate other aggregating proteins that contain prolines. Moreover, CyP40 lacking PPIase activity prevented its capacity for disaggregation in vitro. Finally, we describe a unique structural property of CyP40 that may permit disaggregation to occur in an energy-independent manner. This study identifies a novel human protein disaggregase and, for the first time, demonstrates its capacity to dissolve intracellular amyloids.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Animals; Blotting, Western; Brain; Cognition Disorders; Cyclophilins; Cyclosporine; Disease Models, Animal; Female; HEK293 Cells; Humans; Male; Mice, Transgenic; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Peptidyl-Prolyl Isomerase F; Protein Aggregates; Protein Aggregation, Pathological; tau Proteins; Tauopathies

Parkinson's disease (PD) is characterized by motor dysfunction, which is preceded by a number of non-motor symptoms including olfactory deficits. Aggregation of α-synuclein (α-syn) gives rise to Lewy bodies in dopaminergic neurons and is thought to play a central role in PD pathology. However, whether amyloid fibrils or soluble oligomers of α-syn are the main neurotoxic species in PD remains controversial. Here, we performed a single intracerebroventricular (i.c.v.) infusion of α-syn oligomers (α-SYOs) in mice and evaluated motor and non-motor symptoms. Familiar bedding and vanillin essence discrimination tasks showed that α-SYOs impaired olfactory performance of mice, and decreased TH and dopamine levels in the olfactory bulb early after infusion. The olfactory deficit persisted until 45days post-infusion (dpi). α- SYO-infused mice behaved normally in the object recognition and forced swim tests, but showed increased anxiety-like behavior in the open field and elevated plus maze tests 20 dpi. Finally, administration of α-SYOs induced late motor impairment in the pole test and rotarod paradigms, along with reduced TH and dopamine content in the caudate putamen, 45 dpi. Reduced number of TH-positive cells was also seen in the substantia nigra of α-SYO-injected mice compared to control. In conclusion, i.c.v. infusion of α-SYOs recapitulated some of PD-associated non-motor symptoms, such as increased anxiety and olfactory dysfunction, but failed to recapitulate memory impairment and depressive-like behavior typical of the disease. Moreover, α-SYOs i.c.v. administration induced motor deficits and loss of TH and dopamine levels, key features of PD. Results point to α-syn oligomers as the proximal neurotoxins responsible for early non-motor and motor deficits in PD and suggest that the i.c.v. infusion model characterized here may comprise a useful tool for identification of PD novel therapeutic targets and drug screening.

Topics: alpha-Synuclein; Animals; Behavioral Symptoms; Brain; Cells, Cultured; Discrimination, Psychological; Disease Models, Animal; Embryo, Mammalian; Humans; Injections, Intraventricular; Male; Maze Learning; Mesencephalon; Mice; Mice, Transgenic; Neurons; Olfaction Disorders; Parkinson Disease; Peptides; Recognition, Psychology; Tyrosine 3-Monooxygenase

Aggregated forms of α-synuclein play a crucial role in the pathogenesis of synucleinopathies such as Parkinson's disease (PD). However, the molecular mechanisms underlying the pathogenic effects of α-synuclein are not completely understood. Here we show that asparagine endopeptidase (AEP) cleaves human α-synuclein, triggers its aggregation and escalates its neurotoxicity, thus leading to dopaminergic neuronal loss and motor impairments in a mouse model. AEP is activated and cleaves human α-synuclein at N103 in an age-dependent manner. AEP is highly activated in human brains with PD, and it fragments α-synuclein, which is found aggregated in Lewy bodies. Overexpression of the AEP-cleaved α-synuclein

Topics: alpha-Synuclein; Animals; Asparagine; Cysteine Endopeptidases; Disease Models, Animal; Humans; Mice; Parkinson Disease; Protein Aggregation, Pathological; Proteins; Proteolysis

Alpha-synuclein (α-syn) aggregation represents the pathological hallmark of α-synucleinopathies like Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Toll-like receptors (TLRs) are a family of highly conserved molecules that recognize pathogen-associated molecular patterns and define the innate immunity response. It was previously shown that TLR4 plays a role in the clearance of α-syn, suggesting that TLR4 up-regulation in microglia may be a natural mechanism to improve the clearance of α-syn. However, administration of TLR4 ligands could also lead to dangerous adverse effects associated with the induction of toxic inflammatory responses. Monophosphoryl lipid A (MPLA) is a TLR4 selective agonist and a potent inducer of phagocytosis which does not trigger strong toxic inflammatory responses as compared to lipopolysaccharide (LPS). We hypothesize that MPLA treatment will lead to increased clearance of α-syn inclusions in the brain of transgenic mice overexpressing α-syn in oligodendrocytes under the proteolipid protein promoter (PLP-α-syn mouse model of MSA), without triggering toxic cytokine release, thus leading to a general amelioration of the pathology.. Six month old PLP-α-syn mice were randomly allocated to four groups and received weekly intraperitoneal injections of MPLA (50 or 100 μg), LPS or vehicle. After a 12-week treatment period, motor behavior was assessed with the pole test. Brains and plasma samples were collected for neuropathological and immunological analysis.. Chronic systemic MPLA treatment of PLP-α-syn mice led to increased uptake of α-syn by microglial cells, a significant motor improvement, rescue of nigral dopaminergic and striatal neurons and region-specific reduction of the density of oligodendroglial α-syn cytoplasmic inclusions in the absence of a marked systemic inflammatory response.. Our findings demonstrate beneficial effects of chronic MPLA treatment in transgenic PLP-α-syn mice. MPLA appears to be an attractive therapeutic candidate for disease modification trials in MSA and related α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Lipid A; Male; Mice, Transgenic; Multiple System Atrophy; Neurons; Parkinson Disease; Substantia Nigra; Toll-Like Receptor 4

Topics: alpha-Synuclein; Disease Models, Animal; Humans; Parkinson Disease

Although elevated intraocular pressure (IOP) remains the major risk factor in glaucoma, neurodegenerative processes continue despite effective IOP lowering. Altered α-synuclein antibody (Abs) levels have been reported to play a crucial role. This study aimed at identifying whether α-synuclein Abs are capable to decelerate neuronal decay while providing insights into proteomic changes. Four groups of Sprague Dawley rats received episcleral vein occlusion: (1) CTRL, no intravitreal injection, n = 6, (2) CTRL IgG, intravitreal injection of unspecific IgG, n = 5, (3) Buffer, intravitreal injection of buffer, n = 6, (4), α-synuclein Ab, intravitreal injection of α-synuclein Ab, n = 5. IOP and retinal nerve fiber layer thickness (RNFLT) were monitored and immunohistochemistry, microarray and proteomic analysis were performed. RNFLT was reduced in CTRL, CTRL IgG and Buffer group (all p < 0.01) and α-synuclein Ab group (p = 0.17). Axon and RGC density showed an increased neurodegeneration in CTRL, CTRL IgG and Buffer group (all p < 0.01) and increased neuronal survival in α-synuclein Ab group (p = 0.38 and 0.06, respectively) compared with fellow eyes. Proteomic analysis revealed alterations of cofilin 1 and superoxide dismutase 1 expression. This data indicate that α-synuclein Ab might indirectly modulate the actin cytoskeleton organization and negatively regulate apoptotic processes via cofilin 1 and superoxide dismutase 1.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Apoptosis; Deceleration; Disease Models, Animal; Female; Glaucoma; Intraocular Pressure; Intravitreal Injections; Nerve Degeneration; Neuroprotective Agents; Proteomics; Rats; Rats, Sprague-Dawley; Retina; Retinal Ganglion Cells

Evidence suggests that synapses are affected first in Parkinson's disease (PD). Here, we tested the claim that pathological accumulation of α-synuclein, and subsequent synaptic disruption, occur in absence of dopaminergic neuron loss in PD. We determined early synaptic changes in rats that overexpress human α-synuclein by local injection of viral-vectors in midbrain. We aimed to achieve α-synuclein levels sufficient to induce terminal pathology without significant loss of nigral neurons. We tested synaptic disruption in vivo by analyzing motor defects and binding of a positron emission tomography (PET) radioligand to the vesicular monoamine transporter 2, (VMAT2), [

Topics: alpha-Synuclein; Animals; Carbon Radioisotopes; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Humans; Parkinson Disease; Positron-Emission Tomography; Presynaptic Terminals; Rats; Rats, Transgenic; Substantia Nigra; Synapses; Tetrabenazine; Vesicular Monoamine Transport Proteins

PINK1 deficiency causes the autosomal recessive PARK6 variant of Parkinson's disease. PINK1 activates ubiquitin by phosphorylation and cooperates with the downstream ubiquitin ligase PARKIN, to exert quality control and control autophagic degradation of mitochondria and of misfolded proteins in all cell types.. Global transcriptome profiling of mouse brain and neuron cultures were assessed in protein-protein interaction diagrams and by pathway enrichment algorithms. Validation by quantitative reverse transcriptase polymerase chain reaction and immunoblots was performed, including human neuroblastoma cells and patient primary skin fibroblasts.. In a first approach, we documented Pink1-deleted mice across the lifespan regarding brain mRNAs. The expression changes were always subtle, consistently affecting "intracellular membrane-bounded organelles". Significant anomalies involved about 250 factors at age 6 weeks, 1300 at 6 months, and more than 3500 at age 18 months in the cerebellar tissue, including Srsf10, Ube3a, Mapk8, Creb3, and Nfkbia. Initially, mildly significant pathway enrichment for the spliceosome was apparent. Later, highly significant networks of ubiquitin-mediated proteolysis and endoplasmic reticulum protein processing occurred. Finally, an enrichment of neuroinflammation factors appeared, together with profiles of bacterial invasion and MAPK signaling changes-while mitophagy had minor significance. Immunohistochemistry showed pronounced cellular response of Iba1-positive microglia and GFAP-positive astrocytes; brain lipidomics observed increases of ceramides as neuroinflammatory signs at old age. In a second approach, we assessed PINK1 deficiency in the presence of a stressor. Marked dysregulations of microbial defense factors Ifit3 and Rsad2 were consistently observed upon five analyses: (1) Pink1. Thus, an individual biomarker with expression correlating to progression was not identified. Instead, more advanced disease stages involved additional pathways. Hence, our results identify PINK1 deficiency as an early modulator of innate immunity in neurons, which precedes late stages of neuroinflammation during alpha-synuclein spreading.

Topics: Age Factors; Aging; alpha-Synuclein; Animals; Calcium-Binding Proteins; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Disease Progression; Endoplasmic Reticulum Stress; Gene Expression Profiling; Humans; Lipid Metabolism; Mice; Mice, Transgenic; Microfilament Proteins; Mitophagy; Neuroblastoma; Neurons; Parkinson Disease; Protein Kinases; RNA Splicing; Ubiquitination

Cell-to-cell spreading of misfolded α-synuclein (α-syn) is suggested to contribute to the progression of neuropathology in Parkinson's disease (PD). Compelling evidence supports the hypothesis that misfolded α-syn transmits from neuron-to-neuron and seeds aggregation of the protein in the recipient cells. Furthermore, α-syn frequently appears to propagate in the brains of PD patients following a stereotypic pattern consistent with progressive spreading along anatomical pathways. We have generated a C. elegans model that mirrors this progression and allows us to monitor α-syn neuron-to-neuron transmission in a live animal over its lifespan. We found that modulation of autophagy or exo/endocytosis, affects α-syn transfer. Furthermore, we demonstrate that silencing C. elegans orthologs of PD-related genes also increases the accumulation of α-syn. This novel worm model is ideal for screening molecules and genes to identify those that modulate prion-like spreading of α-syn in order to target novel strategies for disease modification in PD and other synucleinopathies.

Topics: Adenosine Triphosphatases; Aldehyde Oxidoreductases; alpha-Synuclein; Animals; Autophagy; Brain; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Communication; Discoidin Domain Receptor 2; Disease Models, Animal; Endocytosis; Exocytosis; Gene Expression Regulation; Genes, Reporter; Green Fluorescent Proteins; Humans; Neurons; Parkinson Disease, Secondary; Protein Aggregates; Protein Serine-Threonine Kinases; Protein Transport; RNA, Small Interfering; Sirolimus; Spectrometry, Fluorescence; Tryptophan Hydroxylase; Ubiquitin-Protein Ligases

Animal models are essential tools for basic pathophysiological research as well as validation of therapeutic strategies for curing human diseases. However, technical difficulties associated with classical transgenesis approaches in rodent species higher than Mus musculus have prevented this long-awaited development. The availability of viral-mediated gene delivery systems in the past few years has stimulated the production of viruses with unique characteristics. For example, the recombinant adeno-associated virus serotype 9 (rAAV2/9) crosses the blood-brain barrier, is capable of transducing developing cells and neurons after intravenous injection and mediates long-term transduction. Whilst post-natal delivery is technically straightforward, in utero delivery bears the potential of achieving gene transduction in neurons at embryonic stages during which the target area is undergoing development. To test this possibility, we injected rAAV2/9 carrying either A53T mutant human α-synuclein or green fluorescent protein, intracerebroventricularly in rats at embryonic day 16.5. We observed neuronal transgene expression in most regions of the brain at 1 and 3 months after birth. This proof-of-concept experiment introduces a new opportunity to model brain diseases in rats.

Topics: alpha-Synuclein; Animals; Blood-Brain Barrier; Brain; Dependovirus; Disease Models, Animal; Female; Genetic Vectors; Green Fluorescent Proteins; Humans; Injections, Intraventricular; Parkinson Disease; Pregnancy; Rats; Transgenes

Alpha-synuclein (aS) amyloid formation is involved in Parkinson's disease (PD); therefore, small molecules that target aS and affect its aggregation are of interest as future drug candidates. We recently reported modified ring-fused 2-pyridones that modulate aS amyloid formation in vitro. Here, we describe the effects of such molecules on behavioral parameters of a Drosophila model of PD (i.e., flies expressing human aS), using a new approach (implemented in a commercially available FlyTracker system) to quantify fly mobility. FlyTracker allows for automated analysis of walking and climbing locomotor behavior, as it collects large sequences of data over time in an unbiased manner. We found that the molecules per se have no toxic or kinetic effects on normal flies. Feeding aS-expressing flies with the amyloid-promoting molecule FN075, remarkably, resulted in increased fly mobility at early time points; however, this effect switched to reduced mobility at later time points, and flies had shorter life spans than controls. In contrast, an amyloid inhibitor increased both fly kinetics and life span. In agreement with increased aS amyloid formation, the FN075-fed flies had less soluble aS, and in vitro aS-FN075 interactions stimulated aS amyloid formation. In addition to a new quantitative approach to probe mobility (available in FlyTracker), our results imply that aS regulates brain activity such that initial removal (here, by FN075-triggered assembly of aS) allows for increased fly mobility.

Topics: 2-Pyridinylmethylsulfinylbenzimidazoles; alpha-Synuclein; Amyloid; Animals; Animals, Genetically Modified; Behavior, Animal; Brain; Disease Models, Animal; Drosophila melanogaster; Female; Humans; Levodopa; Locomotion; Motor Activity; Parkinson Disease; Pyridones; Recombinant Proteins; Spectroscopy, Fourier Transform Infrared

The lack of technology for direct global-scale targeting of the adult mouse nervous system has hindered research on brain processing and dysfunctions. Currently, gene transfer is normally achieved by intraparenchymal viral injections, but these injections target a restricted brain area. Herein, we demonstrated that intravenous delivery of adeno-associated virus (AAV)-PHP.B viral particles permeated and diffused throughout the neural parenchyma, targeting both the central and the peripheral nervous system in a global pattern. We then established multiple procedures of viral transduction to control gene expression or inactivate gene function exclusively in the adult nervous system and assessed the underlying behavioral effects. Building on these results, we established an effective gene therapy strategy to counteract the widespread accumulation of α-synuclein deposits throughout the forebrain in a mouse model of synucleinopathy. Transduction of A53T-SCNA transgenic mice with AAV-PHP.B-GBA1 restored physiological levels of the enzyme, reduced α-synuclein pathology, and produced significant behavioral recovery. Finally, we provided evidence that AAV-PHP.B brain penetration does not lead to evident dysfunctions in blood-brain barrier integrity or permeability. Altogether, the AAV-PHP.B viral platform enables non-invasive, widespread, and long-lasting global neural expression of therapeutic genes, such as GBA1, providing an invaluable approach to treat neurodegenerative diseases with diffuse brain pathology such as synucleinopathies.

Topics: alpha-Synuclein; Animals; beta-Glucosidase; Blood-Brain Barrier; Brain; Dependovirus; Disease Models, Animal; Electroencephalography; Enzyme Activation; Gene Expression; Gene Order; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Humans; Mice; Mice, Transgenic; Neurons; Transduction, Genetic; Tuberous Sclerosis Complex 1 Protein; Tumor Suppressor Proteins

Mitochondrial and lysosomal dysfunction have been implicated in substantia nigra dopaminergic neurodegeneration in Parkinson's disease (PD), but how these pathways are linked in human neurons remains unclear. Here we studied dopaminergic neurons derived from patients with idiopathic and familial PD. We identified a time-dependent pathological cascade beginning with mitochondrial oxidant stress leading to oxidized dopamine accumulation and ultimately resulting in reduced glucocerebrosidase enzymatic activity, lysosomal dysfunction, and α-synuclein accumulation. This toxic cascade was observed in human, but not in mouse, PD neurons at least in part because of species-specific differences in dopamine metabolism. Increasing dopamine synthesis or α-synuclein amounts in mouse midbrain neurons recapitulated pathological phenotypes observed in human neurons. Thus, dopamine oxidation represents an important link between mitochondrial and lysosomal dysfunction in PD pathogenesis.

Topics: alpha-Synuclein; Animals; Antioxidants; Calcineurin Inhibitors; Cell Line; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Glucosylceramidase; Humans; Lysosomes; Melanins; Mesencephalon; Mice; Mice, Knockout; Mitochondria; Oxidation-Reduction; Oxidative Stress; Parkinson Disease; Protein Deglycase DJ-1; Substantia Nigra; Tacrolimus

Although a causative role of α-synuclein (α-syn) is well established in Parkinson's disease pathogenesis, available animal models of synucleinopathy do not replicate the full range of cellular and behavioral changes characteristic of the human disease. This study was designed to generate a more faithful model of Parkinson's disease by injecting human α-syn fibril seeds into the rat substantia nigra (SN), in combination with adenoassociated virus (AAV)-mediated overexpression of human α-syn, at levels that, by themselves, are unable to induce acute dopamine (DA) neurodegeneration. We show that the ability of human α-syn fibrils to trigger Lewy-like α-synuclein pathology in the affected DA neurons is dramatically enhanced in the presence of elevated levels of human α-syn. This synucleinopathy was fully developed already 10 days after fibril injection, accompanied by progressive degeneration of dopaminergic neurons in SN, neuritic swelling, reduced striatal DA release, and impaired motor behavior. Moreover, a prominent inflammatory response involving both activation of resident microglia and infiltration of CD4

Topics: alpha-Synuclein; Animals; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Disease Models, Animal; Dopaminergic Neurons; Humans; Microglia; Parkinson Disease; Rats; Substantia Nigra

Alpha synuclein (α-syn) is a central player in neurodegeneration, but the mechanisms triggering its pathology are not fully understood. Here we found that α-syn is a highly efficient substrate for arginyltransferase ATE1 and is arginylated in vivo by a novel mid-chain mechanism that targets the acidic side chains of E46 and E83. Lack of arginylation leads to increased α-syn aggregation and causes the formation of larger pathological aggregates in neurons, accompanied by impairments in its ability to be cleared via normal degradation pathways. In the mouse brain, lack of arginylation leads to an increase in α-syn's insoluble fraction, accompanied by behavioral changes characteristic for neurodegenerative pathology. Our data show that lack of arginylation in the brain leads to neurodegeneration, and suggests that α-syn arginylation can be a previously unknown factor that facilitates normal α-syn folding and function in vivo.

Topics: alpha-Synuclein; Amino Acid Sequence; Aminoacyltransferases; Animals; Arginine; Brain; Cells, Cultured; Disease Models, Animal; Humans; Mass Spectrometry; Mice; Mice, Knockout; Models, Biological; Neurodegenerative Diseases; Neurons; Peptides; Protein Aggregates; Protein Aggregation, Pathological; Protein Processing, Post-Translational; Proteolysis; Recombinant Proteins; Substrate Specificity

Synucleinopathies are a spectrum of neurodegenerative diseases characterized by the intracellular deposition of the protein α-synuclein leading to multiple outcomes, including dementia and Parkinsonism. Recent findings support the notion that across the spectrum of synucleinopathies there exist diverse but specific biochemical modifications and/or structural conformations of α-synuclein, which would give rise to protein strain specific prion-like intercellular transmission, a proposed model that could explain synucleinopathies disease progression. Herein, we characterized a panel of antibodies with epitopes within both the C- and N- termini of α-synuclein. A comprehensive analysis of human pathological tissue and mouse models of synucleinopathy with these antibodies support the notion that α-synuclein exists in distinct modified forms and/or structural variants. Furthermore, these well-characterized and specific tools allow the investigation of biochemical changes associated with α-synuclein inclusion formation. We have identified several antibodies of interest with diverse staining and epitope properties that will prove useful in future investigations of strain specific disease progression and the development of targeted immunotherapeutic approaches to synucleinopathies.

Topics: alpha-Synuclein; Animals; Antibodies; Disease Models, Animal; Epitopes; Humans; Lewy Body Disease; Mice; Mice, Inbred BALB C; Mice, Transgenic

The enteric nervous system (ENS) controls the function of the gastrointestinal tract and has been implicated in various diseases, including Parkinson's disease (PD). PD is a neurodegenerative disease with Lewy bodies (LBs) and Lewy neurites (LNs) as the main pathological features. In addition to the typical motor symptoms in PD, attention has been drawn to non-motor symptoms, such as constipation, implying dysfunction of the ENS. In the present study, we characterized the age-dependent morphological alterations and aggregation of α-synuclein (α-syn), the primary protein component in LBs and LNs, in the ENS in an α-syn transgenic mouse model. We found that the expression and accumulation of α-syn increased gradually in neurons of Meissner's and Auerbach's plexuses of the gastrointestinal tract with age (from 1 week to 2 years). In addition, α-syn was increasingly phosphorylated at the serine 129 residue, reflecting pathological alterations of the protein over time. Furthermore, α-syn was present in different subtypes of neurons expressing vasoactive intestinal polypeptide, neuronal nitric oxide synthase, or calretinin. The results indicated that BAC-α-Syn-GFP transgenic mice provide a unique model in which to study the relationship between ENS and PD pathogenesis.

Topics: Age Factors; alpha-Synuclein; Animals; Disease Models, Animal; Enteric Nervous System; Mice; Mice, Transgenic; Neurons; Parkinson Disease; Phosphorylation

Parkinson's disease (PD) is an aging-associated neurodegenerative disease affecting millions worldwide. Misfolding, oligomerization and accumulation of the human α-synuclein protein is a key pathological hallmark of PD and is associated with the progressive loss of dopaminergic neurons over the course of aging. Lifespan extension via the suppression of IGF-1/insulin-like signaling (IIS) offers a possibility to retard disease onset through induction of metabolic changes that provide neuroprotection. The nceh-1 gene of Caenorhabditis elegans encodes an ortholog of neutral cholesterol ester hydrolase 1 (NCEH-1), an IIS downstream protein that was identified in a screen as a modulator of α-synuclein accumulation in vivo. The mechanism whereby cholesterol metabolism functionally impacts neurodegeneration induced by α-synuclein is undefined. Here we report that NCEH-1 protects dopaminergic neurons from α-synuclein-dependent neurotoxicity in C. elegans via a mechanism that is independent of lifespan extension. We discovered that the presence of cholesterol, LDLR-mediated cholesterol endocytosis, and cholesterol efflux are all essential to NCEH-1-mediated neuroprotection. In protecting from α-synuclein neurotoxicity, NCEH-1 also stimulates cholesterol-derived neurosteroid formation and lowers cellular reactive oxygen species in mitochondria. Collectively, this study augments our understanding of how cholesterol metabolism can modulate a neuroprotective mechanism that attenuates α-synuclein neurotoxicity, thereby pointing toward regulation of neuronal cholesterol turnover as a potential therapeutic avenue for PD.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Carboxylic Ester Hydrolases; Cholesterol; Disease Models, Animal; Dopaminergic Neurons; Humans; Neuroprotective Agents; Parkinson Disease; Signal Transduction; Sterol Esterase

The present work examines α-synuclein expression in the nigrostriatal system of a rat chronic hepatic encephalopathy model induced by portacaval anastomosis (PCA). There is evidence that dopaminergic dysfunction in disease conditions is strongly associated with such expression. Possible relationships among dopaminergic neurons, astroglial cells and α-synuclein expression were sought.. Brain tissue samples from rats at 1 and 6 months post-PCA, and controls, were analysed immunohistochemically using antibodies against tyrosine hydroxylase (TH), α-synuclein, glial fibrillary acidic protein (GFAP) and ubiquitin (Ub).. In the control rats, TH immunoreactivity was detected in the neuronal cell bodies and processes in the substantia nigra pars compacta (SNc). A dense TH-positive network of neurons was also seen in the striatum. In the PCA-exposed rats, however, a reduction in TH-positive neurons was seen at both 1 and 6 months in the SNc, as well as a reduction in TH-positive fibres in the striatum. This was coincident with the appearance of α-synuclein-immunoreactive neurons in the SNc; some of the TH-positive neurons also showed α-synuclein immunoreactivity. In addition, α-synuclein accumulation was seen in the SNc and striatum at both 1 and 6 months post-PCA, whereas α-synuclein was only mildly expressed in the nigrostriatal pathway of the controls. Astrogliosis was also seen following PCA, as revealed by increased GFAP expression from 1 month to 6 months post-PCA in both the SN and striatum. The astroglial activation level in the SN paralleled the reduced neuronal expression of TH throughout PCA exposure.. α-synuclein accumulation following PCA may induce dopaminergic dysfunction via the downregulation of TH, as well as astroglial activation.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Disease Progression; Gene Expression; Glial Fibrillary Acidic Protein; Hepatic Encephalopathy; Immunoblotting; Immunohistochemistry; Male; Neurons; Portacaval Shunt, Surgical; Rats, Sprague-Dawley; Substantia Nigra; Tyrosine 3-Monooxygenase; Ubiquitin

The CCAAT/Enhancer binding protein β (C/EBPβ) is a transcription factor involved in numerous physiological as well as pathological conditions in the brain. However, little is known regarding its possible role in neurodegenerative disorders. We have previously shown that C/EBPβ regulates the expression of genes involved in inflammatory processes and brain injury. Here, we have analyzed the effects of C/EBPβ interference in dopaminergic cell death and glial activation in the 6-hydroxydopamine model of Parkinson's disease. Our results showed that lentivirus-mediated C/EBPβ deprivation conferred marked in vitro and in vivo neuroprotection of dopaminergic cells concomitant with a significant attenuation of the level of the inflammatory response and glial activation. Additionally, C/EBPβ interference diminished the induction of α-synuclein in the substantia nigra pars compacta of animals injected with 6-hydroxydopamine. Taking together, these results reveal an essential function for C/EBPβ in the pathways leading to inflammatory-mediated brain damage and suggest novel roles for C/EBPβ in neurodegenerative diseases, specifically in Parkinson's disease, opening the door for new therapeutic interventions.

Topics: alpha-Synuclein; Animals; Apoptosis; CCAAT-Enhancer-Binding Protein-beta; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Mesencephalon; Oxidopamine; Parkinson Disease; Pars Compacta; Rats; Rats, Wistar; RNA Interference; RNA, Small Interfering

The nematode worm Caenorhabditis elegans (C. elegans) is a versatile and widely used animal model for in vivo studies of a broad range of human diseases, in particular for understanding their genetic origins and for screening drug candidates. Nevertheless, the challenges associated with the administration of native proteins to C. elegans have limited the range of applications of this animal model in protein-based drug discovery programs. Here, we describe a readily usable protocol for the transduction of native proteins in C. elegans, which is based on the encapsulation of the proteins of interest within cationic lipid vesicles, prior to their administration to worms. This procedure limits the degradation of the proteins in the guts of the animals, and promotes their adsorption into body tissues. To illustrate the efficacy of this approach we apply it to deliver an antibody designed to inhibit α-synuclein aggregation, and show that it can lead to the rescue of the disease phenotype in a C. elegans model of Parkinson's disease. As this transduction protocol is fast and inexpensive, we anticipate that it will be readily applicable to protein-based drug discovery studies that utilize C. elegans as a model organism.

Topics: Adsorption; alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Genetic Therapy; Humans; Intestinal Absorption; Lipids; Liposomes; Parkinson Disease; Reproducibility of Results

Parkinson's disease (PD) is a neurodegenerative disease that is associated with aging and is characterized as a movement disorder. Currently, there is still no complete therapy for PD. In recent years, the identification and characterization of medicinal plants to cure or treat PD has gained increasing scientific interest.. In this study, we investigated a pentacyclic triterpenoid compound, β-amyrin, which is found in many medicinal plants for its anti-Parkinsonian effects, using Caenorhabditis elegans (C. elegans) disease models and their underlying mechanisms.. C. elegans treated or untreated with β-amyrin were investigated for oxidative stress resistance, neurodegeneration, and α-synuclein aggregation assays. The C. elegans ortholog of Atg8/LC3, LGG-1 that is involved in the autophagy pathway was also evaluated by quantitative RT-PCR and transgenic strain experiments.. β-Amyrin exerted excellent antioxidant activity and reduced intracellular oxygen species in C. elegans. Using the transgenic strain BZ555, β-amyrin showed a protective effect on dopaminergic neurons reducing cell damage induced by 6-hydroxydopamine (6-OHDA). In addition, β-amyrin significantly reduced the α-synuclein aggregation in the transgenic strain NL5901. Moreover, β-amyrin up-regulated LGG-1 mRNA expression and increased the number of localized LGG-1 puncta in the transgenic strain DA2123.. The results from this study suggest that the anti-Parkinsonian effects of β-amyrin might be regulated via LGG-1 involved autophagy pathway in C. elegans. Therefore, β-amyrin may be useful for therapeutic applications or supplements to treat or slow the progression of PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antioxidants; Antiparkinson Agents; Autophagy; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopaminergic Neurons; Microtubule-Associated Proteins; Neurodegenerative Diseases; Oleanolic Acid; Oxidative Stress; Parkinson Disease

Genetic variation in a major histocompatibility complex II (MHCII)-encoding gene (HLA-DR) increases risk for Parkinson disease (PD), and the accumulation of MHCII-expressing immune cells in the brain correlates with α-synuclein inclusions. However, the timing of MHCII-cell recruitment with respect to ongoing neurodegeneration, and the types of cells that express MHCII in the PD brain, has been difficult to understand. Recent studies show that the injection of short α-synuclein fibrils into the rat substantia nigra pars compacta (SNpc) induces progressive inclusion formation in SNpc neurons that eventually spread to spiny projection neurons in the striatum. Herein, we find that α-synuclein fibrils rapidly provoke a persistent MHCII response in the brain. In contrast, equivalent amounts of monomeric α-synuclein fail to induce MHCII or persistent microglial activation, consistent with our results in primary microglia. Flow cytometry and immunohistochemical analyses reveal that MHCII-expressing cells are composed of both resident microglia as well as cells from the periphery that include monocytes, macrophages, and lymphocytes. Over time, α-Synuclein fibril exposures in the SNpc causes both axon loss as well as monocyte recruitment in the striatum. While these monocytes in the striatum initially lack MHCII expression, α-synuclein inclusions later form in nearby spiny projection neurons and MHCII expression becomes robust. In summary, in the rat α-synuclein fibril model, peripheral immune cell recruitment occurs prior to neurodegeneration and microglia, monocytes and macrophages all contribute to MHCII expression.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Antigens, CD; Brain; Calcium-Binding Proteins; Cells, Cultured; Disease Models, Animal; Gene Expression Regulation; HLA-DR Antigens; Inclusion Bodies; Leukocytes, Mononuclear; Mice; Mice, Inbred C57BL; Microfilament Proteins; Microglia; Nitric Oxide Synthase Type II; Parkinson Disease; Rats; Rats, Sprague-Dawley; Tyrosine 3-Monooxygenase

Topics: alpha-Synuclein; Animals; Calcineurin; Disease Models, Animal; Parkinson Disease; Phosphoproteins; Proteome; Rats; Rats, Sprague-Dawley; Tacrolimus; Tacrolimus Binding Protein 1A

(-)-Epigallocatechin gallate (EGCG), the major component of green tea, has been re-evaluated with α-synuclein (αS), a pathological constituent of Parkinson's disease, to elaborate its therapeutic value. EGCG has been demonstrated to not only induce the off-pathway 'compact' oligomers of αS as suggested previously, but also drastically enhance the amyloid fibril formation of αS. Considering that the EGCG-induced amyloid fibrils could be a product of on-pathway SDS-sensitive 'transient' oligomers, the polyphenol effect on the transient 'active' oligomers (AOs) was investigated. By facilitating the fibril formation and thus eliminating the toxic AOs, EGCG was shown to suppress the membrane disrupting radiating amyloid fibril formation on the surface of liposomal membranes and thus protect the cells which could be readily affected by AOs. Taken together, EGCG has been suggested to exhibit its protective effect against the αS-mediated cytotoxicity by not only producing the off-pathway 'compact' oligomers, but also facilitating the conversion of 'active' oligomers into amyloid fibrils.

Topics: alpha-Synuclein; Amyloid; Animals; Catechin; Cell Membrane; Disease Models, Animal; Drosophila melanogaster; Electrophoresis, Polyacrylamide Gel; Microscopy, Electron, Transmission; Parkinson Disease

Exercise has been recommended to improve motor function in Parkinson patients, but its value in altering progression of disease is unknown. In this study, we examined the neuroprotective effects of running wheel exercise in mice. In adult wild-type mice, one week of running wheel activity led to significantly increased DJ-1 protein concentrations in muscle and plasma. In DJ-1 knockout mice, running wheel performance was much slower and Rotarod performance was reduced, suggesting that DJ-1 protein is required for normal motor activity. To see if exercise can prevent abnormal protein deposition and behavioral decline in transgenic animals expressing a mutant human form of α-synuclein in all neurons, we set up running wheels in the cages of pre-symptomatic animals at 12 months old. Activity was monitored for a 3-month period. After 3 months, motor and cognitive performance on the Rotarod and Morris Water Maze were significantly better in running animals compared to control transgenic animals with locked running wheels. Biochemical analysis revealed that running mice had significantly higher DJ-1, Hsp70 and BDNF concentrations and had significantly less α-synuclein aggregation in brain compared to control mice. By contrast, plasma concentrations of α-synuclein were significantly higher in exercising mice compared to control mice. Our results suggest that exercise may slow the progression of Parkinson's disease by preventing abnormal protein aggregation in brain.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Brain-Derived Neurotrophic Factor; Cognition; Disease Models, Animal; Female; HSP70 Heat-Shock Proteins; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Muscle, Skeletal; Parkinson Disease; Physical Conditioning, Animal; Protein Deglycase DJ-1

Neuromodulation by spinal cord stimulation has been proposed as a symptomatic treatment for Parkinson's disease. We tested the chronic effects of spinal cord stimulation in a progressive model of Parkinson's based on overexpression of alpha-synuclein in the substantia nigra. Adult Sprague Dawley rats received unilateral injections of adeno-associated virus serotype 6 (AAV6) in the substantia nigra to express alpha-synuclein. Locomotion and forepaw use of the rats were evaluated during the next 10 weeks. Starting on week 6, a group of AAV6-injected rats received spinal cord stimulation once a week. At the end of the experiment, tyrosine hydroxylase and alpha-synuclein immunostaining were performed. Rats with unilateral alpha-synuclein expression showed a significant decrease in the use of the contralateral forepaw, which was mildly but significantly reverted by spinal cord stimulation applied once a week from the 6th to the 10th week after the AAV6 injection. Long-term spinal cord stimulation proved to be effective to suppress or delay motor symptoms in a sustained and progressive model of Parkinson's and might become an alternative, less invasive neuromodulation option to treat this disease.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Male; Parkinson Disease; Rats; Rats, Sprague-Dawley; Spinal Cord Stimulation; Substantia Nigra

Spinal cord injury (SCI) often causes neurological deficits with poor recovery; the treatment, however, is far from satisfaction, and the mechanisms remain unclear. Using immunohistochemistry and western blotting analysis, we found α-synuclein (SNCA) was significantly up-regulated in the spinal caudal segment of rats subjected to spinal cord transection at 3 days post-operation. Moreover, the role of SNCA on neuronal growth and apoptosis in vitro was determined by using overexpressing and interfering SNCA recombined plasmid vectors, and the underlying mechanism was detected by QRT-PCR and western blotting. Spinal neurons transfected with SNCA-shRNA lentivirus gave rise to an optimal neuronal survival, while it results in cell apoptosis in SNCA-ORF group. In molecular level, SNCA silence induced the up-regulation of CNTF and down-regulation of Caspase7/9. Together, endogenous SNCA plays a crucial role in spinal neuronal survival, in which the underlying mechanism may be linked to the regulation both apoptotic genes (Caspase7/9) and CNTF. The present findings therefore provide novel insights into the role of SNCA in spinal cord and associated mechanism, which may provide novel cue for the treatment of SCI in future clinic trials.

Topics: alpha-Synuclein; Animals; Antigens, Nuclear; Apoptosis; Cell Survival; Ciliary Neurotrophic Factor; Disease Models, Animal; Female; Lentivirus; Nerve Growth Factors; Nerve Tissue Proteins; Neurons; Open Reading Frames; Rats, Sprague-Dawley; RNA, Small Interfering; Spinal Cord; Spinal Cord Injuries; Transfection; Virus Assembly

In most patients, Parkinson's disease is thought to emerge after a lifetime of exposure to, and interaction between, various genetic and environmental risk factors. One of the key genetic factors linked to this condition is α-synuclein, and the α-synuclein protein is pathologically associated with idiopathic cases. However, α-synuclein pathology is also present in presymptomatic, clinically "normal" individuals suggesting that environmental factors, such as Parkinson's disease-linked agricultural pesticides, may be required to precipitate Parkinson's disease in these individuals. In this context, the aim of this study was to assess the behavioural and neuropathological impact of exposing rats with a subclinical load of α-synuclein to subclinical doses of the organic pesticide, rotenone. Rats were randomly assigned to two groups for intra-nigral infusion of AAV

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Functional Laterality; Green Fluorescent Proteins; Insecticides; Male; Motor Disorders; Psychomotor Performance; Rats; Rats, Sprague-Dawley; Rotenone; Substantia Nigra; Time Factors; Transduction, Genetic; Tyrosine 3-Monooxygenase; Vibrissae

Mulberry fruit, which has been long used in traditional oriental medicine, was reported to ameliorate motor dysfunction and dopaminergic neuronal degeneration via antioxidant and antiapoptotic effects in an animal model of Parkinson's disease (PD). More than 95% of PD patients exhibit nonmotor problems such as olfactory dysfunction and gastrointestinal constipation, which are generally considered to be early symptoms of PD. However, few studies have actually examined potential drugs to treat early PD symptoms. The present study examined the protective effects of mulberry fruit extract (ME) against neurotoxicity in a 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine/probenecid (MPTP/p) model of early PD. MPTP/p model was developed by systemic administration with MPTP (25 mg/kg) and probenecid (250 mg/kg) over 5 weeks. The behavioral studies showed that treatment of mice with ME significantly improved PD-related nonmotor symptoms as well as motor impairment, demonstrated by utilizing the olfactory, pole, rotarod and open field tests. In addition, immunohistochemical analysis indicated that ME exhibits the protective effects against dopaminergic neuronal damage induced by MPTP/p in the substantia nigra and striatum. Moreover, by using Western blot analysis, we found that treatment with ME inhibited the up-regulation of α-synuclein and ubiquitin, well known as composition of Lewy bodies in the substantia nigra and striatum of the MPTP/p mice. Taken together, these data suggest that ME may have therapeutic potential for preventing PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antioxidants; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Fruit; Gene Expression Regulation; Male; Mice; Mice, Inbred C57BL; Morus; Neuroprotective Agents; Parkinson Disease; Plant Extracts; Probenecid; Substantia Nigra; Ubiquitin

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Cerebral Cortex; Disease Models, Animal; Hippocampus; Humans; Lysosomal-Associated Membrane Protein 2; Mice; Mice, Transgenic; Neurons; Peptide Fragments; Proteins

Pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD) and Huntington's disease (HD) are closely related to the formation of protein aggregates and inclusion body. For instance, active autophagic components from Chinese herbal medicines (CHMs) are highlighted to modulate neurodegeneration via degradation of disease proteins. In this study, the neuroprotective effect of the purified Hedera helix (HH) fraction containing both hederagenin and α-hederin, is confirmed by the improvement of motor deficits in PD mice model. Furthermore, hederagenin and α-hederin derived from HH are confirmed as novel autophagic enhancers. Both compounds reduce the protein level of mutant huntingtin with 74 CAG repeats and A53T α-synuclein, and inhibit the oligomerization of α-synuclein and inclusion formation of huntingtin, via AMPK-mTOR dependent autophagy induction. Both hederagenin and α-hederin induce autophagy and promote the degradation of neurodegenerative mutant disease proteins in vitro, suggesting the therapeutic roles of HH in neurodegenerative disorders.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Adenylate Kinase; alpha-Synuclein; Animals; Autophagy; Cell Line, Tumor; Disease Models, Animal; Drugs, Chinese Herbal; Female; Hedera; Huntingtin Protein; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Oleanolic Acid; PC12 Cells; Rats; Saponins; TOR Serine-Threonine Kinases

Misfolded α-synuclein (αS) is hypothesized to spread throughout the central nervous system (CNS) by neuronal connectivity leading to widespread pathology. Increasing evidence indicates that it also has the potential to invade the CNS via peripheral nerves in a prion-like manner. On the basis of the effectiveness following peripheral routes of prion administration, we extend our previous studies of CNS neuroinvasion in M83 αS transgenic mice following hind limb muscle (intramuscular [i.m.]) injection of αS fibrils by comparing various peripheral sites of inoculations with different αS protein preparations. Following intravenous injection in the tail veins of homozygous M83 transgenic (M83. The misfolding and accumulation of α-synuclein (αS) inclusions are found in a number of neurodegenerative disorders and is a hallmark feature of Parkinson's disease (PD) and PD-related diseases. Similar characteristics have been observed between the infectious prion protein and αS, including its ability to spread from the peripheral nervous system and along neuroanatomical tracts within the central nervous system. In this study, we extend our previous results and investigate the efficiency of intravenous (i.v.), intraperitoneal (i.p.), and intramuscular (i.m.) routes of injection of αS fibrils and other protein controls. Our data reveal that injection of αS fibrils via these peripheral routes in αS-overexpressing mice are capable of inducing a robust αS pathology and in some cases cause paralysis. Furthermore, soluble, nonaggregated αS also induced αS pathology, albeit with much less efficiency. These findings further support and extend the idea of αS neuroinvasion from peripheral exposures.

Topics: alpha-Synuclein; Animals; Brain; Central Nervous System Diseases; Disease Models, Animal; Inclusion Bodies; Mice; Mice, Transgenic; Neurodegenerative Diseases; Phenotype; Protein Aggregates; Protein Aggregation, Pathological; Spinal Cord

Lysosomal storage disorders (LSDs) are inherited diseases characterized by lysosomal dysfunction and often showing a neurodegenerative course. There is no cure to treat the central nervous system in LSDs. Moreover, the mechanisms driving neuronal degeneration in these pathological conditions remain largely unknown. By studying mouse models of LSDs, we found that neurodegeneration develops progressively with profound alterations in presynaptic structure and function. In these models, impaired lysosomal activity causes massive perikaryal accumulation of insoluble α-synuclein and increased proteasomal degradation of cysteine string protein α (CSPα). As a result, the availability of both α-synuclein and CSPα at nerve terminals strongly decreases, thus inhibiting soluble NSF attachment receptor (SNARE) complex assembly and synaptic vesicle recycling. Aberrant presynaptic SNARE phenotype is recapitulated in mice with genetic ablation of one allele of both CSPα and α-synuclein. The overexpression of CSPα in the brain of a mouse model of mucopolysaccharidosis type IIIA, a severe form of LSD, efficiently re-established SNARE complex assembly, thereby ameliorating presynaptic function, attenuating neurodegenerative signs, and prolonging survival. Our data show that neurodegenerative processes associated with lysosomal dysfunction may be presynaptically initiated by a concomitant reduction in α-synuclein and CSPα levels at nerve terminals. They also demonstrate that neurodegeneration in LSDs can be slowed down by re-establishing presynaptic functions, thus identifying synapse maintenance as a novel potentially druggable target for brain treatment in LSDs.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; HSP40 Heat-Shock Proteins; Lysosomal Storage Diseases; Membrane Proteins; Mice; Neurodegenerative Diseases; Presynaptic Terminals; Proteolysis; SNARE Proteins; Synaptic Vesicles

Type 2 diabetes mellitus (T2DM) is a risk factor for Parkinson's disease (PD). Therefore, treatment to improve insulin resistance in T2DM may be useful for PD patients. Glucose dependent insulinotropic polypeptide (GIP) is a member of the incretin hormone family that can promote insulin release and improve insulin resistance. Several GIP analogues have been developed as potential treatments for T2DM. We had shown previously that D-Ala2-GIP-glu-PAL, a novel long-acting GIP analogue, can play a neuroprotective role in the PD mouse model induced by acute MPTP injection. The drug reduced damage to the dopaminergic neurons and increased CREB-mediated Bcl-2 expression to prevent apoptosis and reduced chronic inflammation in the brain. In the present study, we further tested the effects of chronic treatment by D-Ala2-GIP-glu-PAL in a chronic PD mouse model induced by MPTP (25mg/kg ip.) combination with probenecid (250mg/kg ip.) injection for 5 weeks. The results demonstrated that chronic treatment with D-Ala2-GIP-glu-PAL inhibits MPTP -induced Parkinsonism-like motor disorders in mice, and that the drug prevents dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc). Moreover, D-Ala2-GIP-glu-PAL also inhibited the increased levels of expression of α-synuclein in the SNpc and striatum induced by MPTP. Furthermore, drug treatment reduced chronic neuroinflammation, oxidative stress and lipid peroxidation, and increased the expression of BDNF. These findings show that GIP signaling is neuroprotective and holds promise as a novel treatment of PD.

Topics: alpha-Synuclein; Animals; Astrocytes; Brain-Derived Neurotrophic Factor; Cell Count; Chronic Disease; Disease Models, Animal; Dopaminergic Neurons; Gastric Inhibitory Polypeptide; Gene Expression Regulation; Inflammation; Lipid Peroxidation; Male; Mice; Mice, Inbred C57BL; Microglia; Motor Activity; Neostriatum; Parkinson Disease; Pars Compacta

Diffusion kurtosis imaging (DKI) is sensitive in detecting α-Synuclein (α-Syn) accumulation-associated microstructural changes at late stages of the pathology in α-Syn overexpressing TNWT-61 mice. The aim of this study was to perform DKI in young TNWT-61 mice when α-Syn starts to accumulate and to compare the imaging results with an analysis of motor and memory impairment and α-Syn levels. Three-month-old (3mo) and six-month-old (6mo) mice underwent DKI scanning using the Bruker Avance 9.4T magnetic resonance imaging system. Region of interest (ROI) analyses were performed in the gray matter; tract-based spatial statistics (TBSS) analyses were performed in the white matter. In the same mice, α-Syn expression was evaluated using quantitative immunofluorescence. Mean kurtosis (MK) was the best differentiator between TNWT-61 mice and wildtype (WT) mice. We found increases in MK in 3mo TNWT-61 mice in the striatum and thalamus but not in the substantia nigra (SN), hippocampus, or sensorimotor cortex, even though the immunoreactivity of human α-Syn was similar or even higher in the latter regions. Increases in MK in the SN were detected in 6mo mice. These findings indicate that α-Syn accumulation-associated changes may start in areas with a high density of dopaminergic nerve terminals. We also found TBSS changes in white matter only at 6mo, suggesting α-Syn accumulation-associated changes start in the gray matter and later progress to the white matter. MK is able to detect microstructural changes induced by α-Syn overexpression in TNWT-61 mice and could be a useful clinical tool for detecting early-stage Parkinson's disease in human patients.

Topics: alpha-Synuclein; Animals; Brain; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Memory; Mice; Motor Activity; Motor Skills; Parkinson Disease

Parkinsonian-pyramidal syndrome (PPS) is an early onset form of Parkinson's disease (PD) that shows degeneration of the extrapyramidal region of the brain to result in a severe form of PD. The toxic protein build-up has been implicated in the onset of PPS. Protein removal is mediated by an intracellular proteasome complex: an E3 ubiquitin ligase, the targeting component, is essential for function. FBXO7 encodes the F-box component of the SCF E3 ubiquitin ligase linked to familial forms of PPS. The Drosophila melanogaster homologue nutcracker (ntc) and a binding partner, PI31, have been shown to be active in proteasome function. We show that altered expression of either ntc or PI31 in dopaminergic neurons leads to a decrease in longevity and locomotor ability, phenotypes both associated with models of PD. Furthermore, expression of ntc-RNAi in an established α-synuclein-dependent model of PD rescues the phenotypes of diminished longevity and locomotor control.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Carrier Proteins; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Eye; F-Box Proteins; Female; Gene Expression; Longevity; Male; Organ Specificity; Organogenesis; Parkinson Disease; Protein Binding; Protein Interaction Domains and Motifs

The abnormality of nuclear receptor-related protein 1 (Nurr1) in expression and function can contribute to neurodegeneration of dopaminergic neurons and occurrence of Parkinson's disease (PD). However, its related mechanism in PD is still unknown. In this study, we found that Nurr1 was down-regulated and CCL2 was up-regulated in PD patients and PD mice. CCL2 promoted apoptosis and secretion of TNF-α and IL-1β in SH-SY5Y cells and inhibited cell viability while knockdown of CCL2 exerted the opposite effects. Nurr1 overexpression inhibited apoptosis, the release of TNF-α and IL-1β and promoted viability in α-Syn-treated SH-SY5Y cells, which was markedly promoted by CCL2 antibody and dramatically reversed by CCL2. Nurr1 overexpression negatively regulated CCL2 expression in vivo and in vitro. Furthermore, Nurr1 overexpression remarkably relieved MPTP-induced movement disorder and spatial memory deficits and played neuroprotective and anti-inflammatory roles in MPTP-induced PD mice by down-regulating CCL2 in vivo. In conclusion, Nurr1 overexpression exerts neuroprotective and anti-inflammatory roles via down-regulating CCL2 in both in vivo and in vitro PD models, contributing to developing mechanism-based and neuroprotective strategies against PD.

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Chemokine CCL2; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Down-Regulation; Humans; Inflammation; Interleukin-1beta; Male; Maze Learning; Mice; Mice, Inbred C57BL; Neurons; Neuroprotection; Nuclear Receptor Subfamily 4, Group A, Member 2; Parkinson Disease; Tumor Necrosis Factor-alpha

α-synuclein gene mutations can cause α-synuclein protein aggregation in the midbrain of Parkinson's disease (PD) patients. MicroRNAs (miRNAs) play a key role in the metabolism of α-synuclein but the mechanism involved in synucleinopathy remains unclear. In this study, we investigated the miRNA profiles in A53T-α-synuclein transgenic mice and analyzed the candidate miRNAs in the cerebrospinal fluid (CSF) of PD patients. The 12-month A53T-transgenic mouse displayed hyperactive movement and anxiolytic-like behaviors with α-synuclein aggregation in midbrain. A total of 317,759 total and 289,207 unique small RNA sequences in the midbrain of mice were identified by high-throughput deep sequencing. We found 644 miRNAs were significantly changed in the transgenic mice. Based on the conserved characteristic of miRNAs, we selected 11 candidates from the 40 remarkably expressed miRNAs and explored their expression in 44 CSF samples collected from PD patients. The results revealed that 11 microRNAs were differently expressed in CSF, emphatically as miR-144-5p, miR-200a-3p and miR-542-3p, which were dramatically up-regulated in both A53T-transgenic mice and PD patients, and had a helpful accuracy for the PD prediction. The ordered logistic regression analysis showed that the severity of PD has strong correlation with an up-expression of miR-144-5p, miR-200a-3p and miR-542-3p in CSF. Taken together, our data suggested that miRNAs in CSF, such as miR-144-5p, miR-200a-3p and miR-542-3p, may be useful to the PD diagnosis as potential biomarkers.

Topics: Adult; Aged; Alleles; alpha-Synuclein; Animals; Biomarkers; Case-Control Studies; Disease Models, Animal; Dopaminergic Neurons; Female; Gene Expression Profiling; Gene Expression Regulation; High-Throughput Nucleotide Sequencing; Humans; Hyperkinesis; Male; Mice; Mice, Transgenic; MicroRNAs; Middle Aged; Mutation; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; RNA Interference; Transcriptome

The pesticide rotenone has been shown to cause systemic inhibition of mitochondrial complex I activity, with consequent degeneration of dopamine neurons along the nigrostriatal pathway, as observed in Parkinson's disease (PD). Recently, intracranial infusion of rotenone was found to increase the protein levels of the Lewy body constituents, α-synuclein and small ubiquitin-related modifier-1(SUMO-1), in the lesioned hemisphere of the mouse brain. These findings are supportive of a mouse model of PD, but information about the dopamine-synthesizing enzyme, tyrosine hydroxylase (TH), an essential marker of dopaminergic status, was not reported. Clarification of this issue is important because an intracranial rotenone mouse model of Parkinson's disease has not been established. Towards this end, the present study examined the effects of intracranial rotenone treatment on TH and α-synuclein immunohistochemistry in addition to forelimb motor function. Mice were unilaterally infused with either vehicle or rotenone (2μg/site) in both the medial forebrain bundle and the substantia nigra. The forelimb asymmetry (cylinder) test indicated a significant decrease in use of the contralateral forelimb in lesioned animals as compared to the sham group. Densitometric analysis revealed a significant depletion of TH immunofluorescence within the ipsilateral striatum and substantia nigra of lesioned animals. Moreover, a significant bilateral increase in α-synuclein immunofluorescence was found in the substantia nigra of lesioned mice, as compared to control animals. These findings indicate that this intracranial rotenone mouse model will be useful for studies of neurodegenerative disorders such as PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Immunohistochemistry; Injections, Intraventricular; Insecticides; Male; Mice; Parkinson Disease; Rotenone; Substantia Nigra; Up-Regulation

Rodent models of traumatic brain injury (TBI) reproduce secondary injury sequela and cognitive impairments observed in patients afflicted by a TBI. Impaired neurotransmission has been reported in the weeks following experimental TBI, and may be a contributor to behavioral dysfunction. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, the machinery facilitating vesicular docking and fusion, is a highly-conserved mechanism important for neurotransmission. Following TBI, there is a reduction in both the formation of the SNARE complex and the abundance of multiple SNARE proteins, including the chaperone protein cysteine string protein α (CSPα). Treatment with lithium in naïve rats reportedly increases the expression of CSPα. In the context of TBI, brain-injured rats treated with lithium exhibit improved outcome in published reports, but the mechanisms underlying the improvement are poorly understood. The current study evaluated the effect of lithium administration on the abundance of SNARE proteins and SNARE complex formation, hemispheric tissue loss, and neurobehavioral performance following controlled cortical impact (CCI). Sprague Dawley rats were subjected to CCI or sham injury, and treated daily with lithium chloride or vehicle for up to 14days. Administration of lithium after TBI modestly improved spatial memory at 14days post-injury. Semi-quantitative immunoblot analysis of hippocampal lysates revealed that treatment with lithium attenuated reductions in key SNARE proteins and SNARE complex formation at multiple time points post-injury. These findings highlight that treatment with lithium increased the abundance of synaptic proteins that facilitate neurotransmission and may contribute to improved cognitive function after TBI.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Antimanic Agents; Brain Injuries, Traumatic; Disease Models, Animal; Gene Expression Regulation; Hippocampus; Learning Disabilities; Lithium Chloride; Male; Psychomotor Disorders; Rats; Rats, Sprague-Dawley; SNARE Proteins; Spatial Learning; Synaptophysin; Synaptosomal-Associated Protein 25; Time Factors; Vesicle-Associated Membrane Protein 2

Lewy bodies are considered as the main pathological characteristics of Parkinson's disease (PD). The major component of Lewy bodies is α-synuclein (α-syn). The use of gene therapy that targeting and effectively interfere with the expression of α-syn in neurons has received tremendous attention. In this study, we used magnetic Fe

Topics: Acrylamides; alpha-Synuclein; Animals; Biological Products; Disease Models, Animal; Drug Carriers; Endocytosis; Genetic Therapy; Magnetite Nanoparticles; Male; Mice, Inbred C57BL; Nerve Growth Factor; Neurons; Parkinson Disease; Plasmids; RNA, Small Interfering

Cell-to-cell transmission of α-synuclein (αSyn) is hypothesized to play an important role in disease progression in synucleinopathies. This process involves cellular uptake of extracellular amyloidogenic αSyn seeds followed by seeding of endogenous αSyn. Though it is well known that αSyn is an immunogenic protein that can interact with immune receptors, the role of innate immunity in regulating induction of αSyn pathology in vivo is unknown. Herein, we explored whether altering innate immune activation affects induction of αSyn pathology in wild type mice.. We have previously demonstrated that recombinant adeno-associated virus (AAV) mediated expression of the inflammatory cytokine, Interleukin (IL)-6, in neonatal wild type mice brains leads to widespread immune activation in the brain without overt neurodegeneration. To investigate how IL-6 expression affects induction of αSyn pathology, we injected mouse wild type αSyn fibrils in the hippocampus of AAV-IL-6 expressing mice. Control mice received AAV containing an Empty vector (EV) construct. Two separate cohorts of AAV-IL-6 and AAV-EV mice were analyzed in this study: 4 months or 2 months following intrahippocampal αSyn seeding.. Here, we show that IL-6 expression resulted in widespread gliosis and concurrently reduced αSyn inclusion pathology induced by a single intra-hippocampal injection of exogenous amyloidogenic αSyn. The reduction in αSyn inclusion pathology in IL-6 expressing mice was time-dependent. Suppression of αSyn pathology was accompanied by reductions in both argyrophilic and p62 immunoreactive inclusions.. Our data supports a beneficial role of inflammatory priming of the CNS in wild type mice challenged with exogenous αSyn. A likely mechanism is efficient astroglial scavenging of exogenous αSyn, at least early in the disease process, and in the absence of human αSyn transgene overexpression. Given evidence that a pro-inflammatory environment may restrict seeding of αSyn pathology, this can be used to design anti-αSyn immunobiotherapies by harnessing innate immune function.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Gliosis; Hippocampus; Immunohistochemistry; Inflammation; Interleukin-6; Mice; Mice, Transgenic; Neurodegenerative Diseases

Multiple system atrophy (MSA) is a fatal neurodegenerative disorder characterized by the pathological accumulation of alpha-synuclein (α-syn) in oligodendrocytes. Therapeutic efforts to stop or delay the progression of MSA have yielded suboptimal results in clinical trials, and there are no efficient treatments currently available for MSA patients. We hypothesize that combining therapies targeting different aspects of the disease may lead to better clinical outcomes. To test this hypothesis, we combined the use of a single-chain antibody targeting α-syn modified for improved central nervous system penetration (CD5-D5) with an unconventional anti-inflammatory treatment (lenalidomide) in the myelin basic protein (MBP)-α-syn transgenic mouse model of MSA. While the use of either CD5-D5 or lenalidomide alone had positive effects on neuroinflammation and/or α-syn accumulation in this mouse model of MSA, the combination of both approaches yielded better results than each single treatment. The combined treatment reduced astrogliosis, microgliosis, soluble and aggregated α-syn levels, and partially improved behavioral deficits in MBP-α-syn transgenic mice. These effects were associated with an activation of the Akt signaling pathway, which may mediate cytoprotective effects downstream tumor necrosis factor alpha (TNFα). These results suggest that a strategic combination of treatments may improve the therapeutic outcome in trials for MSA and related neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Disease Models, Animal; Gliosis; Humans; Immunotherapy; Lenalidomide; Mice, Transgenic; Multiple System Atrophy; Proto-Oncogene Proteins c-akt; Signal Transduction; Single-Chain Antibodies; Thalidomide; Tumor Necrosis Factor-alpha

Alpha-synuclein (α-Syn) accumulation is significantly correlated with motor deficits and mitochondrial dysfunction in Parkinson's disease (PD), but the molecular mechanism underlying its pathogenesis is unclear. In this study, we investigated the effects of treadmill exercise on motor deficits and mitochondrial dysfunction in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Treadmill exercise inhibited dopaminergic neuron loss by promoting the expression of tyrosine hydroxylase (TH) and dopamine transporter (DAT) and seemed to improve cell survival by reducing α-Syn expression. Most importantly, treadmill exercise increased expression of the mitochondrial import machinery proteins TOM-40, TOM-20, and TIM-23. This was associated with decreased α-Syn expression and subsequent upregulation of the mitochondrial proteins COX-I, COX-IV, and mtHSP70. Taken together, these results indicate that treadmill exercise may ameliorate motor deficits and improve mitochondrial dysfunction by reducing α-Syn expression in the MPTP-induced mouse model of PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; Dopaminergic Neurons; Exercise Test; Male; Mice; Mice, Inbred C57BL; Mitochondria; MPTP Poisoning; Parkinson Disease; Physical Conditioning, Animal; Substantia Nigra; Tyrosine 3-Monooxygenase

Neurodegenerative disorders such as Parkinson's Disease (PD), PD dementia (PDD) and Dementia with Lewy bodies (DLB) are characterized by progressive accumulation of α-synuclein (α-syn) in neurons. Recent studies have proposed that neuron-to-neuron propagation of α-syn plays a role in the pathogenesis of these disorders. We have previously shown that antibodies against the C-terminus of α-syn reduce the intra-neuronal accumulation of α-syn and related deficits in transgenic models of synucleinopathy, probably by abrogating the axonal transport and accumulation of α-syn in in vivo models. Here, we assessed the effect of passive immunization against α-syn in a new mouse model of axonal transport and accumulation of α-syn. For these purpose, non-transgenic, α-syn knock-out and mThy1-α-syn tg (line 61) mice received unilateral intra-cerebral injections with a lentiviral (LV)-α-syn vector construct followed by systemic administration of the monoclonal antibody 1H7 (recognizes amino acids 91-99) or control IgG for 3 months. Cerebral α-syn accumulation and axonopathy was assessed by immunohistochemistry and effects on behavior were assessed by Morris water maze. Unilateral LV-α-syn injection resulted in axonal propagation of α-syn in the contra-lateral site with subsequent behavioral deficits and axonal degeneration. Passive immunization with 1H7 antibody reduced the axonal accumulation of α-syn in the contra-lateral side and ameliorated the behavioral deficits. Together this study supports the notion that immunotherapy might improve the deficits in models of synucleinopathy by reducing the axonal propagation and accumulation of α-syn. This represents a potential new mode of action through which α-syn immunization might work.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Axonal Transport; Axons; Brain; Disease Models, Animal; Female; Functional Laterality; Genetic Vectors; Humans; Immunization, Passive; Lentivirus; Maze Learning; Mice, Transgenic; Neurodegenerative Diseases

Whole-exome sequencing (WES) has been successful in identifying genes that cause familial Parkinson's disease (PD). However, until now this approach has not been deployed to study large cohorts of unrelated participants. To discover rare PD susceptibility variants, we performed WES in 1148 unrelated cases and 503 control participants. Candidate genes were subsequently validated for functions relevant to PD based on parallel RNA-interference (RNAi) screens in human cell culture and Drosophila and C. elegans models.. Assuming autosomal recessive inheritance, we identify 27 genes that have homozygous or compound heterozygous loss-of-function variants in PD cases. Definitive replication and confirmation of these findings were hindered by potential heterogeneity and by the rarity of the implicated alleles. We therefore looked for potential genetic interactions with established PD mechanisms. Following RNAi-mediated knockdown, 15 of the genes modulated mitochondrial dynamics in human neuronal cultures and four candidates enhanced α-synuclein-induced neurodegeneration in Drosophila. Based on complementary analyses in independent human datasets, five functionally validated genes-GPATCH2L, UHRF1BP1L, PTPRH, ARSB, and VPS13C-also showed evidence consistent with genetic replication.. By integrating human genetic and functional evidence, we identify several PD susceptibility gene candidates for further investigation. Our approach highlights a powerful experimental strategy with broad applicability for future studies of disorders with complex genetic etiologies.

Topics: Adolescent; Adult; alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Case-Control Studies; Cells, Cultured; Child; Disease Models, Animal; Drosophila melanogaster; Exome; Genetic Predisposition to Disease; High-Throughput Nucleotide Sequencing; Humans; Middle Aged; Parkinson Disease; RNA Interference; Sequence Analysis, DNA; Young Adult

Synucleinopathies such as Parkinson's disease or multiple system atrophy are characterized by Lewy bodies in distinct brain areas. These aggregates are mainly formed by α-synuclein inclusions, a protein crucial for synaptic functions in the healthy brain. Transgenic animal models of synucleinopathies are frequently based on over-expression of human wild type or mutated α-synuclein under the regulatory control of different promoters. A promising model is the Line 61 α-synuclein transgenic mouse that expresses the transgene under control of the Thy-1 promoter.. Here, we show an extended characterization of this mouse model over age. To this end, we analyzed animals for the progression of human and mouse protein expression levels in different brain areas as well as motor and memory deficits. Our results show, that Line 61 mice exhibited an age dependent increase of α-synuclein protein levels in the hippocampus but not the striatum. While murine α-synuclein was also increased with age, it was lower expressed in Line 61 mice than in non-transgenic littermates. At the age of 9 months animals exhibited increased neuroinflammation. Furthermore, we found that Line 61 mice showed severe motor deficits as early as 1 month of age as assessed by the wire hanging and nest building tests. At later ages, initial motor deficits were validated with the RotaRod, pasta gnawing and beam walk tests. At 8 months of age animals exhibited emotional memory deficits as validated with the contextual fear conditioning test.. In summary, our results strengthen and further expand our knowledge about the Line 61 mouse model, emphasizing this mouse model as a valuable in vivo tool to test new compounds directed against synucleinopathies.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Cerebral Cortex; Conditioning, Classical; Corpus Striatum; Disease Models, Animal; Disease Progression; Encephalitis; Fear; Hippocampus; Inclusion Bodies; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Parkinson Disease

A pathological hallmark of Alzheimer's disease (AD) are amyloid plaques in the brain consisting of aggregated amyloid-β 42 peptide (Aβ42) derived from cellular amyloid-β protein precursor (AβPP). Based on successful experiments in mouse AD models, active immunization with Aβ42 peptide and passive immunizations with anti-Aβ42 antibodies were started in clinical trials. Active Aβ42 peptide immunization in humans had led to an inflammatory autoimmune response, and the trial was stopped. Passive immunizations had shown some effects in slowing AD pathology. Active DNA Aβ42 immunizations administered with the gene gun into the skin elicits a different immune response and is non-inflammatory. While in rodents, good responses had been found for this type of immunization, positive results in larger mammals are missing. We present here results from sixteen New Zealand White Rabbits, which underwent intradermal DNA Aβ42 immunization via gene gun. The humoral immune response was analyzed from blood throughout the study, and cellular immune responses were determined from spleens at the end of the study. A good anti-Aβ antibody response was found in the rabbit model. The T cell response after re-stimulation in cell culture showed no IFNγ producing cells when ELISPOT assays were analyzed from PBMC, but low numbers of IFNγ and IL-17 producing cells were found in ELISPOTS from spleens (both 5 immunizations). Brains from immunized rabbits showed no signs of encephalitis. Based on these results, DNA Aβ42 immunization is highly likely to be safe and effective to test in a possible clinical AD prevention trial in patients.

Topics: Aging; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Autoantibodies; B-Lymphocytes; Biolistics; Brain; Disease Models, Animal; Drug Evaluation, Preclinical; Epitopes, B-Lymphocyte; Female; Humans; Injections, Intradermal; Male; Mice, Transgenic; Peptide Fragments; Plaque, Amyloid; Rabbits; T-Lymphocytes; Vaccination; Vaccines, DNA

Mutations in the glucocerebrosidase gene (

Topics: alpha-Synuclein; Animals; Carbamates; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; Glucosyltransferases; Humans; Mice; Mutation; Parkinson Disease; Protein Aggregation, Pathological; Quinuclidines; tau Proteins; Ubiquitin

Agitation associated with dementia is frequently reported clinically but has received little attention in preclinical models of dementia. The current study used a 7PA2 CM intracerebroventricular injection model of Alzheimer's disease (AD) to assess acute memory impairment, and a bilateral intrahippocampal (IH) injection model of AD (aggregated Aβ1-42 injections) and a bilateral IH injection model of dementia with Lewy bodies (aggregated NAC61-95 injections) to assess chronic memory impairment in the rat. An alternating-lever cyclic-ratio schedule of operant responding was used for data collection, where incorrect lever perseverations measured executive function (memory) and running response rates (RRR) measured behavioral output (agitation). The results indicate that bilateral IH injections of Aβ1-42 and bilateral IH injections of NAC61-95 decreased memory function and increased RRRs, whereas intracerebroventricular injections of 7PA2 CM decreased memory function but did not increase RRRs. These findings show that using the aggregated peptide IH injection models of dementia to induce chronic neurotoxicity, memory decline was accompanied by elevated behavioral output. This demonstrates that IH peptide injection models of dementia provide a preclinical screen for pharmacological interventions used in the treatment of increased behavioral output (agitation), which also establish detrimental side effects on memory.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Behavior, Animal; Conditioning, Operant; Disease Models, Animal; Executive Function; Hippocampus; Injections, Intraventricular; Lewy Body Disease; Male; Memory Disorders; Peptide Fragments; Psychomotor Agitation; Rats; Rats, Sprague-Dawley

Members of the synaptic vesicle glycoprotein 2 (SV2) family of proteins are involved in synaptic function throughout the brain. The ubiquitously expressed SV2A has been widely implicated in epilepsy, although SV2C with its restricted basal ganglia distribution is poorly characterized. SV2C is emerging as a potentially relevant protein in Parkinson disease (PD), because it is a genetic modifier of sensitivity to l-DOPA and of nicotine neuroprotection in PD. Here we identify SV2C as a mediator of dopamine homeostasis and report that disrupted expression of SV2C within the basal ganglia is a pathological feature of PD. Genetic deletion of SV2C leads to reduced dopamine release in the dorsal striatum as measured by fast-scan cyclic voltammetry, reduced striatal dopamine content, disrupted α-synuclein expression, deficits in motor function, and alterations in neurochemical effects of nicotine. Furthermore, SV2C expression is dramatically altered in postmortem brain tissue from PD cases but not in Alzheimer disease, progressive supranuclear palsy, or multiple system atrophy. This disruption was paralleled in mice overexpressing mutated α-synuclein. These data establish SV2C as a mediator of dopamine neuron function and suggest that SV2C disruption is a unique feature of PD that likely contributes to dopaminergic dysfunction.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Basal Ganglia; Biomarkers; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Gene Deletion; Gene Expression; Humans; Locomotion; Male; Membrane Glycoproteins; Mice; Mice, Knockout; Mice, Transgenic; Middle Aged; Nerve Tissue Proteins; Nicotine; Parkinson Disease; Protein Binding; Synaptic Vesicles

Sirtuin genes have been associated with aging and are known to affect multiple cellular pathways. Sirtuin 2 was previously shown to modulate proteotoxicity associated with age-associated neurodegenerative disorders such as Alzheimer and Parkinson disease (PD). However, the precise molecular mechanisms involved remain unclear. Here, we provide mechanistic insight into the interplay between sirtuin 2 and α-synuclein, the major component of the pathognomonic protein inclusions in PD and other synucleinopathies. We found that α-synuclein is acetylated on lysines 6 and 10 and that these residues are deacetylated by sirtuin 2. Genetic manipulation of sirtuin 2 levels in vitro and in vivo modulates the levels of α-synuclein acetylation, its aggregation, and autophagy. Strikingly, mutants blocking acetylation exacerbate α-synuclein toxicity in vivo, in the substantia nigra of rats. Our study identifies α-synuclein acetylation as a key regulatory mechanism governing α-synuclein aggregation and toxicity, demonstrating the potential therapeutic value of sirtuin 2 inhibition in synucleinopathies.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Acetylation; alpha-Synuclein; Animals; Autophagy; Cell Membrane; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Dopaminergic Neurons; Gene Deletion; Gene Knockdown Techniques; HEK293 Cells; Humans; Lysine; Mice, Inbred C57BL; Mice, Knockout; Mutation; Neuroprotection; Parkinson Disease; Protein Aggregates; Protein Binding; Sirtuin 2

We previously demonstrated that transplantation of murine neural stem cells (NSCs) can improve motor and cognitive function in a transgenic model of Dementia with Lewy Bodies (DLB). These benefits occurred without changes in human α-synuclein pathology and were mediated in part by stem cell-induced elevation of brain-derived neurotrophic factor (BDNF). However, instrastriatal NSC transplantation likely alters the brain microenvironment via multiple mechanisms that may synergize to promote cognitive and motor recovery. The underlying neurobiology that mediates such restoration no doubt involves numerous genes acting in concert to modulate signaling within and between host brain cells and transplanted NSCs. In order to identify functionally connected gene networks and additional mechanisms that may contribute to stem cell-induced benefits, we performed weighted gene co-expression network analysis (WGCNA) on striatal tissue isolated from NSC- and vehicle-injected wild-type and DLB mice. Combining continuous behavioral and biochemical data with genome wide expression via network analysis proved to be a powerful approach; revealing significant alterations in immune response, neurotransmission, and mitochondria function. Taken together, these data shed further light on the gene network and biological processes that underlie the therapeutic effects of NSC transplantation on α-synuclein induced cognitive and motor impairments, thereby highlighting additional therapeutic targets for synucleinopathies.

Topics: alpha-Synuclein; Animals; Cell Movement; Corpus Striatum; Disease Models, Animal; Gene Expression; Green Fluorescent Proteins; Lewy Body Disease; Lysosomes; Mice, Inbred C57BL; Mice, Transgenic; Mitochondria; Neural Stem Cells; Neuroimmunomodulation; Phenotype; Recovery of Function; Stem Cell Transplantation; Synaptic Transmission

Ample evidence has suggested that extracellular α-synuclein aggregates would play key roles in the pathogenesis and progression of Parkinsonian disorders (PDs). In the present study, we investigated whether mesenchymal stem cells (MSCs) and their derived soluble factors could exert neuroprotective effects via proteolysis of extracellular α-synuclein. When preformed α-synuclein aggregates were incubated with MSC-conditioned medium, α-synuclein aggregates were disassembled, and insoluble and oligomeric forms of α-synuclein were markedly decreased, thus leading to a significant increase in neuronal viability. In an animal study, MSC or MSC-conditioned medium treatment decreased the expression of α-synuclein oligomers and the induction of pathogenic α-synuclein with an attenuation of apoptotic cell death signaling. Furthermore, we identified that matrix metalloproteinase-2 (MMP-2), a soluble factor derived from MSCs, played an important role in the degradation of extracellular α-synuclein. Our data demonstrated that MSCs and their derived MMP-2 exert neuroprotective properties through proteolysis of aggregated α-synuclein in PD-related microenvironments. Stem Cells Translational Medicine 2017;6:949-961.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Cell Line; Cell Survival; Culture Media, Conditioned; Disease Models, Animal; Extracellular Space; Humans; Male; Matrix Metalloproteinase 2; Mesenchymal Stem Cells; Mice, Inbred C57BL; Parkinson Disease; Protein Aggregates

Alpha-synuclein (SNCA), a presynaptic protein, is significantly reduced in individuals with Down syndrome (DS) and Ts65Dn mice, a mouse model of DS. Methylation analyses of promoter proximal CpG sites indicate similar reduction in Ts65Dn mice compared to control mice. Epigallocatechin-3-gallate (EGCG), a polyphenolic catechin present in green tea extract, increases methylation of SNCA promoter proximal CpG sites and expression in Ts65Dn mice. These results suggest a positive link between CpG methylation and SNCA expression in Down syndrome.

Topics: alpha-Synuclein; Animals; Catechin; Disease Models, Animal; DNA Methylation; Down Syndrome; Epigenesis, Genetic; Mice; Promoter Regions, Genetic

Acrylamide can form in foods during the cooking process and cause multiple adverse effects. However, the neurotoxicity and mechanisms of acrylamide have not been fully elucidated. In Caenorhabditis elegans, we showed that 48 h exposure to 10-625 mg l(-1) acrylamide resulted in a significant decline in locomotor frequency of body bending, head thrashing and pharynx pumping. In addition, acrylamide exposure reduced crawling speeds and changed angles of body bending. It indicates that acrylamide induces locomotor defects, along with parkinsonian-like movement impairment, including bradykinesia and hypokinesia. Acrylamide also affected chemotaxis plasticity and reduced learning ability. Using transgenic nematodes, we found that acrylamide induced downexpression of P(dat-1) and led to the degeneration of dopaminergic neurons. Moreover, the enhanced expression of unc-54, encoding a subunit of α-synuclein was found. It illustrates that acrylamide is efficient in inducing crucial parkinsonian pathology, including dopaminergic damage and α-synuclein aggregation. These findings suggest the acrylamide-induced locomotor defects and neurotoxicity are associated with Parkinson's disease.

Topics: Acrylamide; alpha-Synuclein; Animals; Caenorhabditis elegans; Chemotaxis; Disease Models, Animal; Dopaminergic Neurons

Parkinson's disease (PD) is a debilitating, progressive, neurodegenerative disorder characterized by progressive loss of dopaminergic neurons and motor deficits. Alpha-synuclein-containing aggregates represent a feature of a variety of neurodegenerative disorders, including PD; however, the mechanism that initiates and promotes intraneuronal alpha-synuclein aggregation remains unknown. We hypothesized protein radical formation as an initiating mechanism for alpha-synuclein aggregation. Therefore, we used the highly sensitive immuno-spin trapping technique to investigate protein radical formation as a possible mechanism of alpha-synuclein aggregation as well as to investigate the source of protein radical formation in the midbrains of Maneb- and paraquat-coexposed mice. Coexposure to Maneb and paraquat for 6 weeks resulted in active microgliosis, NADPH oxidase activation, and inducible nitric oxide synthase (iNOS) induction, which culminated in protein radical formation in the midbrains of mice. Results obtained with immuno-spin trapping and immunoprecipitation experiments confirmed formation of alpha-synuclein radicals in dopaminergic neurons of exposed mice. Free radical formation requires NADPH oxidase and iNOS, as indicated by decreased protein radical formation in knockout mice (P47phox(-/-) and iNOS(-/-)) and in mice treated with inhibitors such as FeTPPS (a peroxynitrite decomposition catalyst), 1400 W (an iNOS inhibitor), or apocynin (a NADPH oxidase inhibitor). Concurrence of protein radical formation with dopaminergic neuronal death indicated a link between protein radicals and disease progression. Taken together, these results show for the first time the formation and detection of the alpha-synuclein radical and suggest that NADPH oxidase and iNOS play roles in peroxynitrite-mediated protein radical formation and subsequent neuronal death in the midbrains of Maneb- and paraquat-coexposed mice.

Topics: alpha-Synuclein; Animals; Cyclic N-Oxides; Disease Models, Animal; Dopaminergic Neurons; Injections, Intraperitoneal; Male; Maneb; Mesencephalon; Mice, Inbred C57BL; Microglia; Models, Biological; NADPH Oxidases; Nitric Oxide Synthase Type II; Paraquat; Parkinson Disease; Peroxynitrous Acid; Spin Labels; Substantia Nigra; Tyrosine 3-Monooxygenase

The accumulation of misfolded α-synuclein in dopamine (DA) neurons is believed to be of major importance in the pathogenesis of Parkinson's disease (PD). Animal models of PD, based on viral-vector-mediated over-expression of α-synuclein, have been developed and show evidence of dopaminergic toxicity, providing us a good tool to investigate potential therapies to interfere with α-synuclein-mediated pathology. An efficient disease-modifying therapeutic molecule should be able to interfere with the neurotoxicity of α-synuclein aggregation. Our study highlighted the ability of an autophagy enhancer, trehalose (at concentrations of 5 and 2% in drinking water), to protect against A53T α-synuclein-mediated DA degeneration in an adeno-associated virus serotype 1/2 (AAV1/2)-based rat model of PD. Behavioral tests and neurochemical analysis demonstrated a significant attenuation in α-synuclein-mediated deficits in motor asymmetry and DA neurodegeneration including impaired DA neuronal survival and DA turnover, as well as α-synuclein accumulation and aggregation in the nigrostriatal system by commencing 5 and 2% trehalose at the same time as delivery of AAV. Trehalose (0.5%) was ineffective on the above behavioral and neurochemical deficits. Further investigation showed that trehalose enhanced autophagy in the striatum by increasing formation of LC3-II. This study supports the concept of using trehalose as a novel therapeutic strategy that might prevent/reverse α-synuclein aggregation for the treatment of PD.

Topics: alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Blood Glucose; Cattle; Cell Survival; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Extremities; Female; Humans; Microtubule-Associated Proteins; Parkinson Disease; Rats, Sprague-Dawley; Solubility; Substantia Nigra; Trehalose; Tyrosine 3-Monooxygenase

We previously reported a loss of cholinergic neurons within the pedunculopontine tegmental nucleus (PPTg) in rats that had been intra-nigrally lesioned with the proteasomal inhibitor lactacystin, with levels of neuronal loss corresponding to that seen in the post-mortem pedunculopontine nucleus (PPN) of advanced Parkinson's disease (PD) patients. Here we reveal lower expression values of the acetylcholine synthesising enzyme, choline acetyltransferase, within the remaining PPTg cholinergic neurons of lesioned rats compared to sham controls. We further characterise this animal model entailing dopaminergic- and non-dopaminergic neurodegeneration by reporting on stereological counts of non-cholinergic neurons, to determine whether the toxin is neuro-type specific. Cell counts between lesioned and sham-lesioned rats were analysed in terms of the topological distribution pattern across the rostro-caudal extent of the PPTg. The study also reports somatic hypotrophy in the remaining non-cholinergic neurons, particularly on the side closest to the nigral lesion. The cytotoxicity affecting the PPTg in this rat model of PD involves overexpression and accumulation of alpha-synuclein (αSYN), affecting cholinergic and non-cholinergic neurons as well as microglia on the lesioned hemispheric side. We ascertained that microglia within the PPTg become fully activated due to the extensive neuronal damage and neuronal death resulting from a lactacystin nigral lesion, displaying a distinct rostro-caudal distribution profile which correlates with PPTg neuronal loss, with the added implication that lactacystin-induced αSYN aggregation might trigger neuronophagia for promoting PPTg cell loss. The data provide critical insights into the mechanisms underlying the lactacystin rat model of PD, for studying the PPTg in health and when modelling neurodegenerative disease.

Topics: Acetylcysteine; alpha-Synuclein; Animals; Cell Count; Choline O-Acetyltransferase; Cholinergic Neurons; Disease Models, Animal; Dopaminergic Neurons; Male; Microglia; Neurons; Parkinson Disease; Parkinsonian Disorders; Pars Compacta; Pedunculopontine Tegmental Nucleus; Protein Aggregation, Pathological; Rats; Rats, Sprague-Dawley; Tyrosine 3-Monooxygenase

Parkinson's disease (PD), is an age-related, progressive neurodegenerative disorder that affects movement and is characterized by the loss of dopaminergic neurons in the nigrostriatal region. Although the clinical and pathological features of PD are complex, recent studies have indicated that microglial NADPH oxidase play a key role in its pathology. A little information is available regarding the role of apocyanin, an NADPH oxidase inhibitor, in ameliorating α-synuclein aggregation and neurobehavioral consequences of PD. Therefore, the present study evaluated its therapeutic potentials for the treatment of neurobehavioral consequences in lipolysaccharide (LPS) induced PD model. For the establishment of PD model LPS (5 μg/5 μl PBS) was injected into the Substantia nigra (SN) of rats. Apocyanin (10mg/kgb.wt) was injected intraperitoneal. Statistical analysis revealed that apocynin significantly ameliorated LPS induced inflammatory response characterized by NFkB, TNF-α and IL-1β upregulation as assessed by ELISA. It also prevented dopaminergic neurons from toxic insult of LPS as indicated by inhibition of apoptotic markers i.e., caspase 3 and caspase 9 as depicted from RT-PCR and ELISA studies. This was further supported by TUNEL assay for DNA fragmentation. Effectiveness of apocyanin in protecting dopaminergic neuronal degeneration was further confirmed by assessment of α-synuclein deposition as depicted by IHC analysis. Consequently, an improvement in the behavioral outcome was observed following apocyanin treatment as depicted from various behavioral tests performed. Hence the data suggests that specific NADPH oxidase inhibitors, such as apocynin, may provide a new therapeutic approach to the control of neurological disabilities induced by LPS induced PD.

Topics: Acetophenones; alpha-Synuclein; Animals; Behavior, Animal; Cytokines; Disease Models, Animal; Dopaminergic Neurons; Enzyme Inhibitors; Lipopolysaccharides; Male; NADPH Oxidases; Parkinson Disease, Secondary; Rats; Rats, Sprague-Dawley

Advanced Parkinson's disease (PD) is characterized by massive degeneration of nigral dopaminergic neurons, dramatic motor and cognitive alterations, and presence of nigral Lewy bodies, whose main constituent is α-synuclein (α-syn). However, the synaptic mechanisms underlying behavioral and motor effects induced by early selective overexpression of nigral α-syn are still a matter of debate.. We performed behavioral, molecular, and immunohistochemical analyses in two transgenic models of PD, mice transgenic for truncated human α-synuclein 1-120 and rats injected with the adeno-associated viral vector carrying wild-type human α-synuclein. We also investigated striatal synaptic plasticity by electrophysiological recordings from spiny projection neurons and cholinergic interneurons.. We found that overexpression of truncated or wild-type human α-syn causes partial reduction of striatal dopamine levels and selectively blocks the induction of long-term potentiation in striatal cholinergic interneurons, producing early memory and motor alterations. These effects were dependent on α-syn modulation of the GluN2D-expressing N-methyl-D-aspartate receptors in cholinergic interneurons. Acute in vitro application of human α-syn oligomers mimicked the synaptic effects observed ex vivo in PD models.. We suggest that striatal cholinergic dysfunction, induced by a direct interaction between α-syn and GluN2D-expressing N-methyl-D-aspartate receptors, represents a precocious biological marker of the disease.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cholinergic Neurons; Dependovirus; Disease Models, Animal; Dopamine; Female; Humans; Long-Term Potentiation; Male; Mice; Mice, Transgenic; Neostriatum; Parkinson Disease; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Recombinant Proteins; Synaptic Transmission

Nonmotor symptoms of cognitive and affective nature are present in premotor and motor stages of Parkinson's disease (PD). Neurogenesis, the generation of new neurons, persists throughout the mammalian life span in the hippocampal dentate gyrus. Adult hippocampal neurogenesis may be severely affected in the course of PD, accounting for some of the neuropsychiatric symptoms such as depression and cognitive impairment. Two important PD-related pathogenic factors have separately been attributed to contribute to both PD and adult hippocampal neurogenesis: dopamine depletion and accumulation of α-synuclein (α-syn). In the acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model, altered neurogenesis has been linked merely to a reduced dopamine level. Here, we seek to determine whether a distinct endogenous α-syn expression pattern is associated, possibly contributing to the hippocampal neurogenic deficit. We observed a persistent reduction of striatal dopamine and a loss of tyrosine hydroxylase-expressing neurons in the substantia nigra pars compacta in contrast to a complete recovery of tyrosine hydroxylase-immunoreactive dopaminergic fibers within the striatum. However, dopamine levels in the hippocampus were significantly decreased. Survival of newly generated neurons was significantly reduced and paralleled by an accumulation of truncated, membrane-associated, insoluble α-syn within the hippocampus. Specifically, the presence of truncated α-syn species was accompanied by increased activity of calpain-1, a calcium-dependent protease. Our results further substantiate the broad effects of dopamine loss in PD-susceptible brain nuclei, gradually involved in the PD course. Our findings also indicate a detrimental synergistic interplay between dopamine depletion and posttranslational modification of α-syn, contributing to impaired hippocampal plasticity in PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Bromodeoxyuridine; Cell Count; Chromatography, High Pressure Liquid; Disease Models, Animal; Dopamine; Doublecortin Domain Proteins; Hippocampus; Ki-67 Antigen; Male; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; MPTP Poisoning; Neurogenesis; Neuropeptides; Spectrin; Tyrosine 3-Monooxygenase

The abnormal accumulation of alpha-synuclein (α-syn) has been linked to a number of neurodegenerative disorders, the most noteworthy of which is Parkinson's disease. Alpha-synuclein itself is not toxic and fulfills various physiological roles in the central nervous system. However, specific types of aggregates have been shown to be toxic, and metals have been linked to the assembly of these toxic aggregates. In this paper, we have characterized a transgenic mouse that overexpresses the A53T mutation of human α-syn, specifically assessing cognition, motor performance, and subtle anatomical markers that have all been observed in synucleinopathies in humans. We hypothesized that treatment with the moderate-affinity metal chelator, clioquinol (CQ), would reduce the interaction between metals and α-syn to subsequently improve the phenotype of the A53T animal model. We showed that CQ prevents an iron-synuclein interaction, the formation of urea-soluble α-syn aggregates, α-syn-related substantia nigra pars compacta cell loss, reduction in dendritic spine density of hippocampal and caudate putamen medium spiny neurons, and the decline in motor and cognitive function. In conclusion, our data suggests that CQ is capable of mitigating the pathological metal/α-syn interactions, suggesting that the modulation of metal ions warrants further study as a therapeutic approach for the synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Clioquinol; Cognition Disorders; Disease Models, Animal; Exploratory Behavior; Humans; Maze Learning; Mice; Mice, Transgenic; Movement Disorders; Mutation; Protein Aggregation, Pathological; Recognition, Psychology; Silver Staining; Spatial Learning

Parkinson's disease (PD) is a debilitating neurodegenerative disease characterized by tremor, rigidity, bradykinesia, and postural instability, for which there is no effective treatment available till date. Here, we report the development of nonviral vectors specific for neuronal cells that can deliver short interfering RNA (siRNA) against the α-synuclein gene (SNCA), and prevent PD-like symptoms both in vitro and in vivo. These vectors not only help siRNA duplexes cross the blood-brain barrier in mice, but also stabilize these siRNAs leading to a sustainable 60-90% knockdown of α-synuclein protein. Mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine rapidly develop PD-like symptoms which were significantly alleviated when SNCA was knocked down using our vectors. Together, our data not only confirm the central role of α-synuclein in the onset of PD, but also provide a proof of principle that these nonviral vectors can be used as novel tools to design effective strategies to combat central nervous system diseases.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Blood-Brain Barrier; Cell Line; Disease Models, Animal; Gene Expression Regulation; Genetic Vectors; Humans; Mice; Parkinson Disease; Peptide Library; RNA, Small Interfering

Parkinson's disease (PD) is pathologically characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the accumulation of aggregated α-synuclein in specific central nervous system (CNS) regions. Disease development is attributed to α-synuclein abnormalities, particularly aggregation and phosphorylation. The ginsenoside Rg1, an active component of ginseng, possesses neuroprotective and anti-inflammatory effects. The purpose of the present study was to evaluate these activities of Rg1 in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/probenecid (MPTP/p)-induced PD mouse model for the first time and to elucidate the underlying mechanisms. Oral treatment with Rg1 significantly attenuated the high MPTP-induced mortality, behavior defects, loss of dopamine neurons and abnormal ultrastructure changes in the SNpc. Other assays indicated that the protective effect of Rg1 may be mediated by its anti-neuroinflammatory properties. Rg1 regulated MPTP-induced reactive astrocytes and microglia and decreased the release of cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the SNpc. Rg1 also alleviated the unusual MPTP-induced increase in oligomeric, phosphorylated and disease-related α-synuclein in the SNpc. In conclusion, Rg1 protects dopaminergic neurons, most likely by reducing aberrant α-synuclein-mediated neuroinflammation, and holds promise for PD therapeutics.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Anti-Inflammatory Agents; Disease Models, Animal; Ginsenosides; Inflammation; Interleukin-1beta; Male; Mice; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Parkinson Disease; Parkinsonian Disorders; Probenecid; Substantia Nigra; Tumor Necrosis Factor-alpha

α-Synuclein (α-syn) has been implicated in neurological disorders with parkinsonism, including Parkinson's disease and Dementia with Lewy body. Recent studies have shown α-syn oligomers released from neurons can propagate from cell-to-cell in a prion-like fashion exacerbating neurodegeneration. In this study, we examined the role of the endosomal sorting complex required for transport (ESCRT) pathway on the propagation of α-syn. α-syn, which is transported via the ESCRT pathway through multivesicular bodies for degradation, can also target the degradation of the ESCRT protein-charged multivesicular body protein (CHMP2B), thus generating a roadblock of endocytosed α-syn. Disruption of the ESCRT transport system also resulted in increased exocytosis of α-syn thus potentially increasing cell-to-cell propagation of synuclein. Conversely, delivery of a lentiviral vector overexpressing CHMP2B rescued the neurodegeneration in α-syn transgenic mice. Better understanding of the mechanisms of intracellular trafficking of α-syn might be important for understanding the pathogenesis and developing new treatments for synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Case-Control Studies; Cell Line; Disease Models, Animal; Endosomal Sorting Complexes Required for Transport; Humans; Lewy Bodies; Lewy Body Disease; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Neurons; Parkinson Disease; Parkinsonian Disorders

Mutations in leucine-rich repeat kinase 2 (LRRK2) cause autosomal-dominant Parkinsonism with pleomorphic pathology including deposits of aggregated protein and neuronal degeneration. The pathogenesis of LRRK2-linked Parkinson's disease (PD) is not fully understood. Here, using co-immunoprecipitation, we found that LRRK2 interacted with synphilin-1 (SP1), a cytoplasmic protein that interacts with α-synuclein and has implications in PD pathogenesis. LRRK2 interacted with the N-terminus of SP1 whereas SP1 predominantly interacted with the C-terminus of LRRK2, including kinase domain. Co-expression of SP1 with LRRK2 increased LRRK2-induced cytoplasmic aggregation in cultured cells. Moreover, SP1 also attenuated mutant LRRK2-induced toxicity and reduced LRRK2 kinase activity in cultured cells. Knockdown of SP1 by siRNA enhanced LRRK2 neuronal toxicity. In vivo Drosophila studies, co-expression of SP1 and mutant G2019S-LRRK2 in double transgenic Drosophila increased survival and improved locomotor activity. Expression of SP1 protects against G2019S-LRRK2-induced dopamine neuron loss and reduced LRRK2 phosphorylation in double transgenic fly brains. Our findings demonstrate that SP1 attenuates mutant LRRK2-induced PD-like phenotypes and plays a neural protective role.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Carrier Proteins; Cell Line, Tumor; Disease Models, Animal; Dopamine; Drosophila; Gene Knockdown Techniques; HEK293 Cells; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Neurons; Parkinson Disease; Phosphorylation; Protein Interaction Domains and Motifs

Parkinson's disease (PD) is a prevalent degenerative disorder affecting the CNS that is primarily characterized by resting tremor and movement deficits. Group I metabotropic glutamate receptor subtypes 1 and 5 (mGluR1 and mGluR5, respectively) are important targets for investigation in several CNS disorders. In the present study, we investigated the in vivo roles of mGluR1 and mGluR5 in chronic PD pathology by performing longitudinal positron emission tomography (PET) imaging in A53T transgenic (A53T-Tg) rats expressing an abnormal human α-synuclein (ASN) gene. A53T-Tg rats showed a dramatic decline in general motor activities with age, along with abnormal ASN aggregation and striatal neuron degeneration. In longitudinal PET imaging, striatal nondisplaceable binding potential (BPND) values for [(11)C]ITDM (N-[4-[6-(isopropylamino) pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methyl-4-[(11)C]methylbenzamide), a selective PET ligand for mGluR1, temporarily increased before PD symptom onset and dramatically decreased afterward with age. However, striatal BPND values for (E)-[(11)C]ABP688 [3-(6-methylpyridin-2-ylethynyl)-cyclohex-2-enone-(E)-O-[(11)C]methyloxime], a specific PET ligand for mGluR5, remained constant during experimental terms. The dynamic changes in striatal mGluR1 BPND values also showed a high correlation in pathological decreases in general motor activities. Furthermore, declines in mGluR1 BPND values were correlated with decreases in BPND values for [(18)F]FE-PE2I [(E)-N-(3-iodoprop-2E-enyl)-2β-carbo-[(18)F]fluoroethoxy-3β-(4-methylphenyl) nortropane], a specific PET ligand for the dopamine transporter, a biomarker for dopaminergic neurons. In conclusion, our results have demonstrated for the first time that dynamic changes occur in mGluR1, but not mGluR5, that accompany pathological progression in a PD animal model.. Synaptic signaling by glutamate, the principal excitatory neurotransmitter in the brain, is modulated by group I metabotropic glutamate receptors, including the mGluR1 and mGluR5 subtypes. In the brain, mGluR1 and mGluR5 have distinct functional roles and regional distributions. Their roles in brain pathology, however, are not well characterized. Using longitudinal PET imaging in a chronic rat model of PD, we demonstrated that expression of mGluR1, but not mGluR5, dynamically changed in the striatum accompanying pathological PD progression. These findings imply that monitoring mGluR1 in vivo may provide beneficial information to further understand central nervous system disorders.

Topics: Alanine; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Disease Progression; Excitatory Amino Acid Agents; Exploratory Behavior; Female; Humans; Motor Activity; Oximes; Parkinson Disease; Protein Binding; Pyridines; Radioisotopes; Radionuclide Imaging; Rats; Rats, Transgenic; Receptors, Metabotropic Glutamate; Threonine; Time Factors

Alpha-synuclein aggregation is the central hallmark of both sporadic and familial Parkinson's disease (PD). Patients with different PD-causing genetic defects of alpha-synuclein usually show distinctive clinical features that are atypical to sporadic PD. Iron accumulation is invariably found in PD. Recent studies showed that mutant and wild-type alpha-synuclein may have differential interaction with iron and mutant alpha-synuclein toxicity could be preferentially exacerbated by iron. We hence hypothesized that iron overload could selectively influence mutant alpha-synuclein toxicity and disease phenotypes. To test the hypothesis, we investigated if Drosophila melanogaster over-expressing A53T, A30P, and wild-type (WT) alpha-synuclein have different responses to iron treatment. We showed that iron treatment induced similar reduction of survival rate in all flies but induced a more severe motor decline in A53T and A30P mutant alpha-synuclein expressing flies, suggesting interaction between mutant alpha-synuclein and iron. Although no significant difference in total head iron content was found among these flies, we demonstrated that iron treatment induced selective DA neuron loss in motor-related PPM3 cluster only in the flies that express A53T and A30P mutant alpha-synuclein. We provided the first in vivo evidence that iron overload could induce distinctive neuropathology and disease phenotypes in mutant but not WT alpha-synuclein expressing flies, providing insights to the cause of clinical features selectively exhibited by mutant alpha-synuclein carriers.

Topics: alpha-Synuclein; Amino Acid Substitution; Animals; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Humans; Iron; Motor Neurons; Mutation, Missense; Parkinson Disease; Phenotype

Acupuncture has historically been practiced to treat medical disorders by mechanically stimulating specific acupoints with fine needles. Despite its well-documented efficacy, its biological basis remains largely elusive. In this study, we found that mechanical stimulation at the acupoint of Yanglingquan (GB34) promoted the autophagic clearance of α-synuclein (α-syn), a well known aggregation-prone protein closely related to Parkinson's disease (PD), in the substantia nigra par compacta (SNpc) of the brain in a PD mouse model. We found the protein clearance arose from the activation of the autophagy-lysosome pathway (ALP) in a mammalian target of rapamycin (mTOR)-independent approach. Further, we observed the recovery in the activity of dopaminergic neurons in SNpc, and improvement in the motor function at the behavior level of PD mice. Whereas acupuncture and rapamycin, a chemical mTOR inhibitor, show comparable α-syn clearance and therapeutic effects in the PD mouse model, the latter adopts a distinctly different, mTOR-dependent, autophagy induction process. Due to this fundamental difference, acupuncture may circumvent adverse effects of the rapamycin treatment. The newly discovered connection between acupuncture and autophagy not only provides a new route to understanding the molecular mechanism of acupuncture but also sheds new light on cost-effective and safe therapy of neurodegenerative diseases.

Topics: Acupuncture; Acupuncture Therapy; alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Dopaminergic Neurons; Lysosomes; Male; Mice; Neurons; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; Signal Transduction; Substantia Nigra; TOR Serine-Threonine Kinases

Abnormal α-synuclein is deposited in neuronal cytoplasmic inclusions and presynapses in Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Previously we have shown that NUB1 is accumulated in these specific regions together with abnormal α-synuclein and that NUB1 is able to inhibit α-synuclein aggregation in cultured cells. We therefore created transgenic (Tg) mice expressing both NUB1 and abnormal α-synuclein to investigate the role of NUB1 on degradation of abnormal α-synuclein in vivo. Immunohistochemical and biochemical studies confirmed that NUB1 was over-expressed in neurons of mice expressing NUB1 (NUB1 Tg), and both NUB1 and abnormal α-synuclein (double Tg). NUB1 levels were increased by 4.7-fold in NUB1 Tg mice compared with wild type mice. Unexpectedly, normal and abnormal α-synuclein levels were unchanged between abnormal α-synuclein Tg mice (Lewy body disease model mice) and double Tg mice, and pathological observations were almost similar between them. Finally, we found that the levels of insoluble α-synuclein were lower and those of some chaperone molecules were higher in double Tg mice compared with abnormal α-synuclein Tg mice. These results suggest that increased levels of NUB1 play a potential role in degradation of detergent-insoluble α-synuclein in vivo, although it is insufficient to degrade abnormal α-synuclein in Lewy body disease model mice.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Gene Expression Regulation; HEK293 Cells; HeLa Cells; Humans; Lewy Body Disease; Mice; Mice, Inbred C57BL; Mice, Transgenic

Lewy bodies (LBs) are intraneuronal inclusions consisting primarily of fibrillized human α-synuclein (hα-Syn) protein, which represent the major pathological hallmark of Parkinson's disease (PD). Although doubling hα-Syn expression provokes LB pathology in humans, hα-Syn overexpression does not trigger the formation of fibrillar LB-like inclusions in mice. We hypothesized that interactions between exogenous hα-Syn and endogenous mouse synuclein homologs could be attenuating hα-Syn fibrillization in mice, and therefore, we systematically assessed hα-Syn aggregation propensity in neurons derived from α-Syn-KO, β-Syn-KO, γ-Syn-KO, and triple-KO mice lacking expression of all three synuclein homologs. Herein, we show that hα-Syn forms hyperphosphorylated (at S129) and ubiquitin-positive LB-like inclusions in primary neurons of α-Syn-KO, β-Syn-KO, and triple-KO mice, as well as in transgenic α-Syn-KO mouse brains in vivo. Importantly, correlative light and electron microscopy, immunogold labeling, and thioflavin-S binding established their fibrillar ultrastructure, and fluorescence recovery after photobleaching/photoconversion experiments showed that these inclusions grow in size and incorporate soluble proteins. We further investigated whether the presence of homologous α-Syn species would interfere with the seeding and spreading of α-Syn pathology. Our results are in line with increasing evidence demonstrating that the spreading of α-Syn pathology is most prominent when the injected preformed fibrils and host-expressed α-Syn monomers are from the same species. These findings provide insights that will help advance the development of neuronal and in vivo models for understanding mechanisms underlying hα-Syn intraneuronal fibrillization and its contribution to PD pathogenesis, and for screening pharmacologic and genetic modulators of α-Syn fibrillization in neurons.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Knockout; Neurons; Parkinson Disease

Potential health effects of radiofrequency (RF) radiation from mobile phones arouse widespread public concern. RF fields from handheld devices near the brain might trigger or aggravate brain tumors or neurodegenerative diseases such as Parkinson's disease (PD). Aggregation of neural α-synuclein (S) is central to PD pathophysiology, and invertebrate models expressing human S have helped elucidate factors affecting the aggregation process. We have recently developed a transgenic strain of Caenorhabditis elegans carrying two S constructs: SC tagged with cyan (C) blue fluorescent protein (CFP), and SV with the Venus (V) variant of yellow fluorescent protein (YFP). During S aggregation in these SC+SV worms, CFP, and YFP tags are brought close enough to allow Foerster Resonance Energy Transfer (FRET). As a positive control, S aggregation was promoted at low Hg(2+) concentrations, whereas higher concentrations activated stress-response genes. Using two different exposure systems described previously, we tested whether RF fields (1.0 GHz CW, 0.002-0.02 W kg(-1); 1.8 GHz CW or GSM, 1.8 W kg(-1)) could influence S aggregation in SC+SV worms. YFP fluorescence in similar SV-only worms provided internal controls, which should show opposite changes due to FRET quenching during S aggregation. No statistically significant changes were observed over several independent runs at 2.5, 24, or 96 h. Although our worm model is sensitive to chemical promoters of aggregation, no similar effects were attributable to RF exposures.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Microwaves; Parkinson Disease; Protein Aggregates; Radiometry

Development of disease modifying therapeutics for Parkinson's disease (PD), the second most common neurodegenerative disorder, relies on availability of animal models which recapitulate the disease hallmarks. Only few transgenic mouse models, which mimic overexpression of alpha-synuclein, show dopamine loss, behavioral impairments and protein aggregation. Mice overexpressing human wildtype alpha-synuclein under the Thy-1 promotor (Thy1-aSyn) replicate these features. However, female mice do not exhibit a phenotype. This was attributed to a potentially lower transgene expression located on the X chromosome. Here we support that female mice overexpress human wildtype alpha-synuclein only about 1.5 fold in the substantia nigra, compared to about 3 fold in male mice. Since female Thy1-aSyn mice were shown previously to exhibit differences in corticostriatal communication and synaptic plasticity similar to their male counterparts we hypothesized that female mice use compensatory mechanisms and strategies to not show overt motor deficits despite an underlying endophenotype. In order to unmask these deficits we translated recent findings in PD patients that sensory abnormalities can enhance motor dysfunction into a novel behavioral test, the adaptive rotating beam test. We found that under changing sensory input female Thy1-aSyn mice showed an overt phenotype. Our data supports that the integration of sensorimotor information is likely a major contributor to symptoms of movement disorders and that even low levels of overexpression of human wildtype alpha-synuclein has the potential to disrupt processing of these information. The here described adaptive rotating beam test represents a sensitive behavioral test to detect moderate sensorimotor alterations in mouse models.

Topics: Adaptation, Psychological; alpha-Synuclein; Analysis of Variance; Animals; Disease Models, Animal; Female; Gait Disorders, Neurologic; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nystagmus, Pathologic; Parkinson Disease; RNA, Messenger; Sex Factors; Substantia Nigra; Time Factors

Safflower has long been used to treat cerebrovascular diseases in China. We previously reported that kaempferol derivatives of safflower can bind DJ-1, a protein associated with Parkinson's disease (PD), and flavonoid extract of safflower exhibited neuroprotective effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of PD. In this study, a standardized safflower flavonoid extract (SAFE) was isolated from safflower and mainly contained flavonoids. Two marker compounds of SAFE, kaempferol 3-O-rutinoside and anhydrosafflor yellow B, were proven to suppress microtubule destabilization and decreased cell area, respectively. We confirmed that SAFE in dripping pill form could improve behavioural performances in a 6-hydroxydopamine (6-OHDA)-induced rat model of PD, partially via the suppression of α-synuclein overexpression or aggregation, as well as the suppression of reactive astrogliosis. Using an MRI tracer-based method, we found that 6-OHDA could change extracellular space (ECS) diffusion parameters, including a decrease in tortuosity and the rate constant of clearance and an increase in the elimination half-life of the tracer in the 6-OHDA-lesioned substantia nigra. SAFE treatment could partially inhibit the changes in ECS diffusion parameters, which might provide some information about neuronal loss and astrocyte activation. Consequently, our results indicate that SAFE is a potential therapeutic herbal product for treatment of PD.

Topics: alpha-Synuclein; Animals; Carthamus tinctorius; Cell Survival; Disease Models, Animal; Flavonoids; Kaempferols; Magnetic Resonance Imaging; Male; Microtubules; Molecular Structure; Neurons; Neuroprotective Agents; Neurotoxins; Oxidopamine; Parkinson Disease, Secondary; PC12 Cells; Pigments, Biological; Plant Extracts; Rats; Rats, Sprague-Dawley; Substantia Nigra

Increasing evidence points to inflammation as a chief mediator of Parkinson's disease (PD), a progressive neurodegenerative disorder characterized by loss of dopamine neurons in the substantia nigra pars compacta (SNpc) and widespread aggregates of the protein α-synuclein (α-syn). Recently, microRNAs, small, noncoding RNAs involved in regulating gene expression at the posttranscriptional level, have been recognized as important regulators of the inflammatory environment. Using an array approach, we found significant upregulation of microRNA-155 (miR-155) in an in vivo model of PD produced by adeno-associated-virus-mediated expression of α-syn. Using a mouse with a complete deletion of miR-155, we found that loss of miR-155 reduced proinflammatory responses to α-syn and blocked α-syn-induced neurodegeneration. In primary microglia from miR-155(-/-) mice, we observed a markedly reduced inflammatory response to α-syn fibrils, with attenuation of major histocompatibility complex class II (MHCII) and proinflammatory inducible nitric oxide synthase expression. Treatment of these microglia with a synthetic mimic of miR-155 restored the inflammatory response to α-syn fibrils. Our results suggest that miR-155 has a central role in the inflammatory response to α-syn in the brain and in α-syn-related neurodegeneration. These effects are at least in part due to a direct role of miR-155 on the microglial response to α-syn. These data implicate miR-155 as a potential therapeutic target for regulating the inflammatory response in PD.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Cells, Cultured; Disease Models, Animal; Inflammation Mediators; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; MicroRNAs; Parkinson Disease

Ankyrin-rich BTB/POZ domain containing protein-2 or BPOZ-2, a scaffold protein, has been recently shown to control the degradation of many biological proteins ranging from embryonic development to tumor progression. However, its role in the process of neuronal diseases has not been properly explored. Since, abnormal clearance of metabolic proteins contributes to the development of alpha-synuclein (α-syn) pathologies in Parkinson's disease (PD), we are interested to explore if BPOZ-2 participates in the amelioration of α-syn in vivo in basal ganglia. Here we report that lentiviral administration of bpoz-2 gene indeed lowers the burden of α-syn in DA neurons in the nigra of A53T transgenic (A53T-Tg) mouse. Our detailed immunological analyses have shown that the overexpression of bpoz-2 dramatically improves both somatic and neuritic α-syn pathologies in the nigral DA neurons. Similarly, the specific ablation of bpoz-2 by lentiviral-shRNA stimulates the load of monomeric and polymeric forms of α-syn in the nigral DA neurons of A53T-Tg. While investigating the mechanism, we observed that BPOZ-2 was involved in a protein-protein association with PINK1 and therefore could stimulate PINK1-dependent autophagic clearance of α-syn. Our results have demonstrated that bpoz-2 gene delivery could have prospect in the amelioration of alpha-synucleinopathy in PD and other Lewy body diseases.

Topics: alpha-Synuclein; Animals; Basal Ganglia; Caenorhabditis elegans Proteins; Disease Models, Animal; Male; Mice; Mice, Transgenic; Neurons; Nuclear Proteins; Parkinson Disease; Protein Binding; Protein Serine-Threonine Kinases; Substantia Nigra

Multiple system atrophy (MSA) is a fatal rapidly progressive α-synucleinopathy, characterized by α-synuclein accumulation in oligodendrocytes. It is accepted that the pathological α-synuclein accumulation in the brain of MSA patients plays a leading role in the disease process, but little is known about the events in the early stages of the disease. In this study we aimed to define potential roles of the miRNA-mRNA regulatory network in the early pre-motor stages of the disease, i.e., downstream of α-synuclein accumulation in oligodendroglia, as assessed in a transgenic mouse model of MSA. We investigated the expression patterns of miRNAs and their mRNA targets in substantia nigra (SN) and striatum, two brain regions that undergo neurodegeneration at a later stage in the MSA model, by microarray and RNA-seq analysis, respectively. Analysis was performed at a time point when α-synuclein accumulation was already present in oligodendrocytes at neuropathological examination, but no neuronal loss nor deficits of motor function had yet occurred. Our data provide a first evidence for the leading role of gene dysregulation associated with deficits in immune and inflammatory responses in the very early, non-symptomatic disease stages of MSA. While dysfunctional homeostasis and oxidative stress were prominent in SN in the early stages of MSA, in striatum differential gene expression in the non-symptomatic phase was linked to oligodendroglial dysfunction, disturbed protein handling, lipid metabolism, transmembrane transport and altered cell death control, respectively. A large number of putative miRNA-mRNAs interaction partners were identified in relation to the control of these processes in the MSA model. Our results support the role of early changes in the miRNA-mRNA regulatory network in the pathogenesis of MSA preceding the clinical onset of the disease. The findings thus contribute to understanding the disease process and are likely to pave the way towards identifying disease biomarkers for early diagnosis of MSA.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Humans; Mice; Mice, Transgenic; MicroRNAs; Multiple System Atrophy; Oligodendroglia; RNA, Messenger

In order to study the molecular pathways of Parkinson's disease (PD) and to develop novel therapeutic strategies, scientific investigators rely on animal models. The identification of PD-associated genes has led to the development of genetic PD models. Most transgenic α-SYN mouse models develop gradual α-SYN pathology but fail to display clear dopaminergic cell loss and dopamine-dependent behavioral deficits. This hurdle was overcome by direct targeting of the substantia nigra with viral vectors overexpressing PD-associated genes. Local gene delivery using viral vectors provides an attractive way to express transgenes in the central nervous system. Specific brain regions can be targeted (e.g. the substantia nigra), expression can be induced in the adult setting and high expression levels can be achieved. Further, different vector systems based on various viruses can be used. The protocol outlines all crucial steps to perform a viral vector injection in the substantia nigra of the rat to develop a viral vector-based alpha-synuclein animal model for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Gene Transfer Techniques; Genetic Vectors; Injections; Mice, Transgenic; Parkinson Disease; Rats, Wistar; Substantia Nigra; Transgenes

Dementia is a nonmotor feature of Parkinson's disease, arising around the onset of hippocampal pathology in stage IV of the disease, from where it progress to the isocortex. Differential α-synuclein involvement in hippocampal interneuron populations remains unknown. The objective of this study was to analyze the involvement of α-synuclein in hippocampal interneurons in an α-synucleinopathy mouse model and in the brains of Parkinson's disease patients.. The distribution of α-synuclein was examined in the dentate gyrus and CA1, CA2, and CA3 fields of the hippocampus in A53T transgenic mice at 16, 30, 43, and 56 weeks and in Parkinson's disease patients at neuropathological stages III, IV, and V. Expression of interneuron markers (mouse: calbindin, calretinin, and somatostatin; human: parvalbumin and somatostatin) were quantified and compared. Coexpression of these markers with α-synuclein was analyzed.. In mice, α-synuclein expression was most concentrated in the granular and polymorphic layers of the dentate gyrus and in the CA2 and CA3 fields. Expression significantly increased at 30 and 43 weeks and then significantly decreased at 56 weeks. In human brains, a significantly higher density of α-synuclein was observed in the CA2. The expression of interneuron markers was, in general, not significantly different between control and transgenic animals, except in calbindin and somatostatin at 43 weeks. The α-synuclein protein colocalized with somatostatin and calbindin in the mouse hippocampus and with parvalbumin in the human hippocampus.. The differential α-synucleinopathy of hippocampal interneuron populations may help in the study of mechanisms of protein aggregation and progression relevant to PD and PD dementia. © 2016 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Hippocampus; Humans; Interneurons; Mice; Mice, Transgenic; Parkinson Disease; Tissue Banks

Activity-dependent neuroprotective protein (ADNP) is essential for brain formation and neuronal survival. It is possible that intracellular alpha-synuclein (α-syn) inclusions may be due to, or may cause, down-regulation of ADNP expression.. This study were to determine whether ADNP protein levels are altered in nigral dopaminergic neurons, establish whether ADNP alterations are associated with α-syn accumulation, and evaluate potential correlations between levels of ADNP expression and axonal transport motor proteins in sporadic and experimental Parkinson's disease (PD).. Twenty human brains from PD (n = 12) and age-matched controls (n = 8) and sixteen rat brains received α-synuclein gene (n = 8) or empty vector (n = 8) were analyzed using immunohistochemistry. The number of ADNP labeled nigral neurons were estimated with stereology and the levels of ADNP were determined using densitometry.. Compared to age-matched controls, a marked reduction in ADNP protein levels was observed in neuromelanin-containing nigral neurons of PD. Reduced ADNP levels did no relate to the progression of PD symptoms, but instead occurred at early PD stages, before reductions in tyrosine hydroxylase could be detected. Reductions in ADNP were also positively correlated with alterations in axonal transport motor protein. Reductions in ADNP levels were recapitulated in a rat model of PD based on viral over-expression of human wild-type α-synuclein, suggesting that ADNP reductions in PD are a direct result of α-synuclein overexpression.. These findings demonstrate that the down-regulation of protein ADNP is an early pathological alteration and may contribute to dopaminergic neurodegeneration in PD.

Topics: alpha-Synuclein; Animals; Autopsy; Disease Models, Animal; Dopaminergic Neurons; Female; Homeodomain Proteins; Humans; Immunohistochemistry; Male; Nerve Tissue Proteins; Parkinson Disease; Parkinsonian Disorders; Rats

Multiple system atrophy (MSA) is a rare atypical parkinsonian disorder characterized by a rapidly progressing clinical course and at present without any efficient therapy. Neuropathologically, myelin loss and neurodegeneration are associated with α-synuclein accumulation in oligodendrocytes, but underlying pathomechanisms are poorly understood. Here, we analyzed the impact of oligodendrocytic α-synuclein on the formation of myelin sheaths to define a potential interventional target for MSA. Post-mortem analyses of MSA patients and controls were performed to quantify myelin and oligodendrocyte numbers. As pre-clinical models, we used transgenic MSA mice, a myelinating stem cell-derived oligodendrocyte-neuron co-culture, and primary oligodendrocytes to determine functional consequences of oligodendrocytic α-synuclein overexpression on myelination. We detected myelin loss accompanied by preserved or even increased numbers of oligodendrocytes in post-mortem MSA brains or transgenic mouse forebrains, respectively, indicating an oligodendrocytic dysfunction in myelin formation. Corroborating this observation, overexpression of α-synuclein in primary and stem cell-derived oligodendrocytes severely impaired myelin formation, defining a novel α-synuclein-linked pathomechanism in MSA. We used the pro-myelinating activity of the muscarinic acetylcholine receptor antagonist benztropine to analyze the reversibility of the myelination deficit. Transcriptome profiling of primary pre-myelinating oligodendrocytes demonstrated that benztropine readjusts myelination-related processes such as cholesterol and membrane biogenesis, being compromised by oligodendrocytic α-synuclein. Additionally, benztropine restored the α-synuclein-induced myelination deficit of stem cell-derived oligodendrocytes. Strikingly, benztropine also ameliorated the myelin deficit in transgenic MSA mice, resulting in a prevention of neuronal cell loss. In conclusion, this study defines the α-synuclein-induced myelination deficit as a novel and crucial pathomechanism in MSA. Importantly, the reversible nature of this oligodendrocytic dysfunction opens a novel avenue for an intervention in MSA.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Benztropine; Brain; Cell Death; Cells, Cultured; Coculture Techniques; Disease Models, Animal; Dose-Response Relationship, Drug; Gliosis; Male; Mice, Transgenic; Multiple System Atrophy; Neurons; Oligodendroglia; Rats, Wistar; Stem Cells; Transcriptome

Parkinson disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra (SN) and diminished dopamine content in the striatum, which is at least partly associated with α-synuclein protein overexpression in these neurons. Recent reports show that 7,8-dihydroxyflavone (DHF), a TrkB agonist, has beneficial effects in animal model of PD. However, it is unclear whether the therapeutic effects of DHF are associated with the expression of α-synuclein.. In this study, we investigated the protective effects of DHF on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced deficit of motor functions, the loss of dopaminergic neurons and the expression of α-synuclein as well as antioxidative activity in the C57BL/6 mice.. Mice were treated with MPTP (30 mg/kg, i.p.) once a day for 5 days to induce dopaminergic neuron death in the SN. DHF (5 mg/kg, i.p.) was administrated once a day from the first day of MPTP injection until 9 days after the last injection of MPTP. Behavioral tests showed that DHF succeeded in ameliorating the impaired motor functions in the MPTP-treated mice. The immunohistochemical assay showed that the amelioration of motor function was accompanied by a reduction in the loss of dopaminergic neurons in the SN and striatum. Western blot analyses showed that DHF prevented the inactivation of TrkB and suppressed α-synuclein overexpression in the SN and striatum following MPTP treatment. Antioxidative activity detection revealed that DHF prevented MPTP-induced reduction in glutathione and total superoxide dismutase activity in the SN and striatum.. Taken together, these results indicate that DHF treatment may suppress the accumulation of α-synuclein and oxidative stress via activating TrkB and subsequently block the loss of dopaminergic neurons in the SN and striatum, thereby ameliorating MPTP-induced motor deficits in the C57BL/6 mice.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Antiparkinson Agents; Cell Death; Disease Models, Animal; Flavones; Gene Expression Regulation; Mice; Mice, Inbred C57BL; Movement; MPTP Poisoning; Oxidative Stress; Psychomotor Performance; Receptor, trkA; Rotarod Performance Test; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is the most common neurodegenerative movement disorder, yet disease-modifying treatments do not currently exist. Rho-associated protein kinase (ROCK) was recently described as a novel neuroprotective target in PD. Since alpha-synuclein (α-Syn) aggregation is a major hallmark in the pathogenesis of PD, we aimed to evaluate the anti-aggregative potential of pharmacological ROCK inhibition using the isoquinoline derivative Fasudil, a small molecule inhibitor already approved for clinical use in humans. Fasudil treatment significantly reduced α-Syn aggregation in vitro in a H4 cell culture model as well as in a cell-free assay. Nuclear magnetic resonance spectroscopy analysis revealed a direct binding of Fasudil to tyrosine residues Y133 and Y136 in the C-terminal region of α-Syn. Importantly, this binding was shown to be biologically relevant using site-directed mutagenesis of these residues in the cell culture model. Furthermore, we evaluated the impact of long-term Fasudil treatment on α-Syn pathology in vivo in a transgenic mouse model overexpressing human α-Syn bearing the A53T mutation (α-Syn(A53T) mice). Fasudil treatment improved motor and cognitive functions in α-Syn(A53T) mice as determined by Catwalk(TM) gait analysis and novel object recognition (NOR), without apparent side effects. Finally, immunohistochemical analysis revealed a significant reduction of α-Syn pathology in the midbrain of α-Syn(A53T) mice after Fasudil treatment. Our results demonstrate that Fasudil, next to its effects mediated by ROCK-inhibition, directly interacts with α-Syn and attenuates α-Syn pathology. This underscores the translational potential of Fasudil as a disease-modifying drug for the treatment of PD and other synucleinopathies.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; alpha-Synuclein; Amides; Animals; Brain; Carrier Proteins; Cell Line, Tumor; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; Humans; Mice; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Parkinson Disease; Protein Aggregates; Protein Kinase Inhibitors; Psychomotor Performance; Pyridines; Recognition, Psychology; Time Factors; Tyrosine 3-Monooxygenase

This study investigates the role of thiol homeostasis disruption in Parkinson's disease (PD) pathogenesis using a novel animal model. A single unilateral administration of the thiol oxidant, diamide (1.45 μmol) into substantia nigra (SN) of mice leads to locomotor deficits and degeneration of dopaminergic (DA) neurons in SN pars compacta (SNpc).. Diamide-injected mice showed hemiparkinsonian behavior, measured as spontaneous contralateral body rotations, poor grip strength, and impaired locomotion on a rotarod. We observed a significant loss of DA neurons in ipsilateral but not contralateral SNpc and their striatal fibers. This was accompanied by increased Fluoro-Jade C-positive cells and a loss of NeuN-positive neurons, indicative of neurodegeneration. Importantly, diamide injection led to α-synuclein aggregation in ipsilateral SNpc, a hallmark of PD pathology not often seen in animal models of PD. On investigating putative mechanism(s) involved, we observed a loss of glutathione, which is essential for maintaining protein thiol homeostasis (PTH). Concomitantly, the redox-sensitive ASK1-p38 mitogen-activated protein kinase (MAPK) death signaling pathway was activated in the ipsilateral but not contralateral ventral midbrain through dissociation of ASK1-Trx1 complex. In Neuro-2a cells, diamide activated ASK1-p38 cascade through Trx1 oxidation, leading to cell death, which was abolished by ASK1 knockdown.. Since diamide selectively disrupts PTH, DA neurons appear to be vulnerable to such perturbations and even a single insult with a thiol oxidant can result in long-lasting degeneration.. Identification of the role of PTH dysregulation in neurodegeneration, especially in early PD, not only facilitates an understanding of novel regulatory features of molecular signaling cascades but also may aid in developing disease-modifying strategies for PD. Antioxid. Redox Signal. 25, 252-267.

Topics: alpha-Synuclein; Animals; Cell Line; Diamide; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Glutathione; Locomotion; Male; MAP Kinase Kinase Kinase 5; MAP Kinase Signaling System; Mice; p38 Mitogen-Activated Protein Kinases; Parkinson Disease; Parkinsonian Disorders; Substantia Nigra; Sulfhydryl Compounds

Mutations in GBA1, the gene encoding glucocerebrosidase, are associated with an enhanced risk of developing synucleinopathies such as Parkinson's disease (PD) and dementia with Lewy bodies. A higher prevalence and increased severity of motor and non-motor symptoms is observed in PD patients harboring mutant GBA1 alleles, suggesting a link between the gene or gene product and disease development. Interestingly, PD patients without mutations in GBA1 also exhibit lower levels of glucocerebrosidase activity in the central nervous system (CNS), implicating this lysosomal enzyme in disease pathogenesis. Here, we investigated whether modulation of glucocerebrosidase activity in murine models of synucleinopathy (expressing wild type Gba1) affected α-synuclein accumulation and behavioral phenotypes. Partial inhibition of glucocerebrosidase activity in PrP-A53T-SNCA mice using the covalent inhibitor conduritol-B-epoxide induced a profound increase in soluble α-synuclein in the CNS and exacerbated cognitive and motor deficits. Conversely, augmenting glucocerebrosidase activity in the Thy1-SNCA mouse model of PD delayed the progression of synucleinopathy. Adeno-associated virus-mediated expression of glucocerebrosidase in the Thy1-SNCA mouse striatum led to decrease in the levels of the proteinase K-resistant fraction of α-synuclein, amelioration of behavioral aberrations and protection from loss of striatal dopaminergic markers. These data indicate that increasing glucocerebrosidase activity can influence α-synuclein homeostasis, thereby reducing the progression of synucleinopathies. This study provides robust in vivo evidence that augmentation of CNS glucocerebrosidase activity is a potential therapeutic strategy for PD, regardless of the mutation status of GBA1.

Topics: alpha-Synuclein; Animals; Cognition; Disease Models, Animal; Dopamine; Gaucher Disease; Gene Expression; Glucosylceramidase; Humans; Mice; Motor Activity; Mutation; Parkinson Disease

This study aimed to explore whether the regulatory effect of miR-21 on α-synuclein expression in neurons is a potential mechanism by which geniopside (GP) protects the central nervous system from Parkinson disease (PD).. The human neuroblastoma cell line SH-SY5Y was induced to differentiate in vitro and treated with dimethyl sulfoxide (DMSO), N-methyl-4-phenylpyridinium iodide (MPP(+)), and MPP(+) together with GP. To identify the role of miR-21 in the regulation of lysosome-associated membrane protein 2 (LAMP2A) and α-synuclein, SH-SY5Y cells pretreated with MPP(+) were transfected with miR-21 mimic and miR-21 inhibitor. To identify whether GP could reduce the level of α-synuclein through miR-21/LAMP2A, SHSY5Y cells pretreated with GP were treated with miR-21 mimic or miR-21 inhibitor; meanwhile, a luciferase reporter assay was performed to confirm the direct target of miR-21. LAMP2A was overexpressed using a pCMV6-XL5-LAMP2A vector to confirm the role of LAMP2A in the regulation of α-synuclein by miR-21. In these in vitro experiments, the RNA and/or protein expressions of miR-21, LAMP2A, and α-synuclein in SH-SY5Y cells were determined by quantitative real-time polymerase chain reaction and/or western blotting, respectively. An in vivo PD mouse model was established through intraperitoneal injection with N-methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP). The mice were treated with saline, MPTP, MPTP+GP, and MPTP+GP+miR-21 agomir. The numbers of TH(+) cells in the substantia nigra in different groups of mice were compared. The RNA and/or protein expressions of miR-21, LAMP2A, and α-synuclein were also determined.. The level of miR-21 in the cells or mice models was significantly higher than that in normal cells or normal mice, respectively, and GP significantly downregulated miR-21. GP also raised the protein and mRNA expressions of LAMP2A and reduced the protein level of α-synuclein in PD models. MiR-21 upregulated the expression of α-synuclein by directly targeting 3' UTR of LAMP2A. LAMP2A overexpression abolished the upregulating effect of miR-21 mimic on α-synuclein. MiR-21 mimics/agomir reversed the GP-induced downregulation of α-synuclein; miR-21 inhibitor effectively increased the downregulation of α-synuclein caused by GP.. GP exhibits neuroprotective properties by inhibiting α-synuclein expression in PD models through the miR-21/LAMP2A axis.

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Disease Models, Animal; Dopaminergic Neurons; Humans; Iridoids; Lysosomal-Associated Membrane Protein 2; Mice; MicroRNAs; Neuroprotective Agents; Parkinson Disease; Parkinsonian Disorders; Substantia Nigra; Tyrosine 3-Monooxygenase

Activating transcription factor 4 (ATF4) is a member of the PERK signaling pathway, which directly binds endoplasmic reticulum stress target genes and plays a crucial role in both adaptations to stress and activation of apoptosis. Previous publications demonstrated conflicting evidence on the role of ATF4 in the pathogenesis of neurodegenerative disorders. In this study, we used recombinant adeno-associate virus (rAAV)-mediated gene transfer to investigate if the sustained up-regulation of ATF4 launches a pro-survival or pro-death trend in the dopamine (DA) cells of the substantia nigra pars compacta in a rat model of Parkinson-like neurodegeneration induced by human alpha-synuclein (αS) overexpression. We showed that ATF4 does not protect nigral DA neurons against an αS-induced pathology. Moreover, the rAAV-mediated overexpression of ATF4 resulted in severe nigra-striatal degeneration via activation of caspases 3/7.

Topics: Activating Transcription Factor 4; alpha-Synuclein; Animals; Apoptosis; Caspase 3; Caspase 7; Disease Models, Animal; Dopaminergic Neurons; Female; Humans; Parkinson Disease; Pars Compacta; Rats; Rats, Sprague-Dawley; Tyrosine 3-Monooxygenase; Up-Regulation

Similar to Parkinson disease, multiple system atrophy (MSA) presents neuropathologically with nigral neuronal loss; however, the hallmark intracellular α-synuclein (αSyn) accumulation in MSA affects typically oligodendrocytes to form glial cytoplasmic inclusions. The underlying pathogenic mechanisms remain unclear. As MSA is predominantly sporadic, epigenetic mechanisms may play a role. We tested the effects of the pan-histone deacetylase inhibitor (HDACi) sodium phenylbutyrate in aged mice overexpressing αSyn under the control of the proteolipid protein promoter (PLP-αSyn) designed to model MSA and characterized by αSyn accumulation in oligodendrocytes and nigral neurodegeneration. HDACi improved motor behavior and survival of nigral neurons in PLP-αSyn mice. Furthermore, HDACi reduced the density of oligodendroglial αSyn aggregates, which correlated with the survival of nigral neurons in PLP-αSyn mice. For the first time, we suggest a role of HDACi in the pathogenesis of MSA-like neurodegeneration and support the future development of selective HDACi for MSA therapy.

Topics: Aging; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Epigenesis, Genetic; Female; Gait Disorders, Neurologic; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Multiple System Atrophy; Myelin Proteolipid Protein; Neuroglia; Neurons; Neuroprotective Agents; Phenylbutyrates; Promoter Regions, Genetic; Protein Deglycase DJ-1

Dan-zhi-xiao-yao-san is a Traditional Chinese Medicinal formulation widely used for the treatment of neuropsychological disorders. The present study examined the anxiolytic and neuroprotective effects of Dan-zhi-xiao-yao-san in a rat model of chronic stress. The results of an elevated plus maze test showed that Dan‑zhi‑xiao‑yao‑san significantly attenuated the levels of anxiety-induced stress as evidenced by increases in the time spent in the open arm region, as well as the percentage of entries into this area. In addition, Dan-zhi-xiao-yao-san alleviated stress‑induced neuronal death, as indicated by histological examination. Furthermore, mechanistic studies suggested that the anxiolytic and neuroprotective effects of Dan-zhi-xiao-yao-san may be mediated via attenuation of chronic stress‑induced upregulation of α‑synuclein and corticosterone, and downregulation of protein phosphatase 2A (PP2A) in the hippocampal region of the brain at the mRNA and protein level. In addition, Dan‑zhi‑xiao‑yao‑san decreased the serum levels of stress‑induced corticosterone in the model animals. In conclusion, the present study demonstrated that Dan‑zhi‑xiao‑yao‑san exerted anxiolytic and neuroprotective effects in a rat model of chronic stress via attenuation of stress‑induced upregulation of α‑synuclein and corticosterone, and downregulation of PP2A in the hippocampus.

Topics: alpha-Synuclein; Animals; Anti-Anxiety Agents; Anxiety; Behavior, Animal; Brain; Chronic Disease; Disease Models, Animal; Drugs, Chinese Herbal; Female; Immunohistochemistry; Maze Learning; Neuroprotective Agents; Protein Phosphatase 2; Rats; Stress, Physiological; Stress, Psychological

The accumulation of misfolded α-synuclein in dopaminergic neurons is the leading cause of Parkinson's disease (PD). Resveratrol (RV), a polyphenolic compound derived from grapes and red wine, exerts a wide range of beneficial effects via activation of sirtuin 1 (SIRT1) and induction of vitagenes. Here, we assessed the role of RV in a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) induced mouse model of PD and explored its potential mechanisms.. RV and EX527, a specific inhibitor of SIRT1, were administered before and after MPTP treatment. RV protected against MPTP-induced loss of dopaminergic neurons, and decreases in tyrosine hydroxylase and dopamine levels, as well as behavioral impairments. Meanwhile, RV administration activated SIRT1. Microtubule-associated protein 1 light chain 3 (LC3) was then deacetylated and redistributed from the nucleus to the cytoplasm, which provoked the autophagic degradation of α-synuclein in dopaminergic neurons. Furthermore, EX527 antagonized the neuroprotective effects of RV by reducing LC3 deacetylation and subsequent autophagic degradation of α-synuclein.. We showed that RV ameliorated both motor deficits and pathological changes in MPTP-treated mice via activation of SIRT1 and subsequent LC3 deacetylation-mediated autophagic degradation of α-synuclein. Our observations suggest that RV may be a potential prophylactic and/or therapeutic agent for PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Acetylation; alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Corpus Striatum; Disease Models, Animal; Dopamine; Male; Mice, Inbred C57BL; Microtubule-Associated Proteins; Neuroprotective Agents; Parkinson Disease, Secondary; Resveratrol; Sirtuin 1; Stilbenes

Aggregation of misfolded disease-related proteins is a hallmark of neurodegenerative diseases. Aggregate propagation accompanying disease progression has been demonstrated for different proteins (eg, for α-synuclein). Additional evidence supports aggregate cross-seeding activity for α-synuclein. For mutated superoxide dismutase 1 (SOD1), which causes familial amyotrophic lateral sclerosis (ALS), self-propagation of aggregation and cell-to-cell transmission have been demonstrated in vitro. However, there is a prominent lack of in vivo data concerning aggregation and cross-aggregation processes of SOD1. We analyzed the effect of α-synuclein and SOD1 seeds in cell culture using protein fragment complementation assay and intracerebral injection of α-synuclein and SOD1 seeds into SOD1(G93A) transgenic ALS mice. Survival of injected mice was determined, and SOD1 aggregates in the facial nuclei were quantified during disease course. We found that α-synuclein preformed fibrils increased the oligomerization rate of SOD1 in vivo and in vitro, whereas aggregated SOD1 did not exert any effect in both experimental setups. Notably, survival of ALS mice was not changed after inoculation of preformed fibrils. We conclude that misfolded α-synuclein can increase SOD1 aggregation and suppose that α-synuclein seeds are transported from the temporal cortex to the facial nuclei. However, unlike other proteins, the further enhancement of a self-aggregation process by additional SOD1 could not be confirmed in our models.

Topics: alpha-Synuclein; Amyotrophic Lateral Sclerosis; Animals; Disease Models, Animal; Humans; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mice, Transgenic; Real-Time Polymerase Chain Reaction; Superoxide Dismutase-1

Misfolded α-synuclein (α-Syn) aggregates participate in the pathogenesis of synucleinopathies, such as Parkinson's disease. Whereas much is known about how the various domains within full-length α-Syn (FL-α-Syn) contribute to the formation of α-Syn aggregates and therefore to their neurotoxicity, little is known about whether the individual peptides that can be generated from α-syn, possibly as intermediate metabolites during degradation of misfolded α-Syn aggregates, are neurotoxic themselves.. A series of synthesized α-Syn peptides, corresponding to the locus in FL-α-Syn containing alanine 30, substitution of which with a proline causes a familial form of Parkinson's disease, were examined for their capacity of inducing release of microglial superoxide. The neurotoxicity of these peptides was measured according to their influence on the ability of neuroglial cultures deficient in gp91 (phox) , the catalytic unit of NADPH oxidase (Nox2), or wild-type cultures to take up (3)H-labeled dopamine and on the number of tyrosine hydroxylase-staining-positive neurons. Western blots and confocal images were utilized to analyze membrane translocation of p47 (phox) and p67 (phox) , phosphorylation of p47 (phox) and Erk1/2 kinase, and binding of α-Syn peptides to gp91 (phox) . Activation of brain microglia in mice injected with α-Syn peptides was demonstrated by immunostaining for major histocompatibility complex (MHC)-II along with qPCR for Iba-1 and MHC-II.. We report α-Syn (29-40) as a specific peptide capable of activating microglial Nox2 to produce superoxide and cause dopaminergic neuronal damage. Administered to mice, this peptide also activated brain microglia to increase expression of MHC-II and Iba-1 and stimulated oxidation reaction. Exploring the underlying mechanisms showed that α-Syn (29-40) peptide triggered Nox2 to generate extracellular superoxide and its metabolite H2O2 by binding to the catalytic unit gp91 (phox) of Nox2; diffusing into cytosol, H2O2 activated Erk1/2 kinase to phosphorylate p47 (phox) and p67 (phox) and further activated Nox2, establishing a positive feedback loop to amplify the Nox2-mediated response.. Collectively, our study suggests novel information regarding how α-Syn causes neuronal injury, possibly including mechanisms involving abnormal metabolites of α-Syn aggregates.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Calcium-Binding Proteins; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Embryo, Mammalian; Histocompatibility Antigens Class II; MAP Kinase Signaling System; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Microfilament Proteins; NADPH Oxidase 2; NADPH Oxidases; Neuroglia; Peptide Fragments; Protein Transport; Receptors, Immunologic; Superoxides; Tyrosine 3-Monooxygenase

Common neurodegenerative proteinopathies, such as Alzheimer's disease (AD) and Parkinson's disease (PD), are characterized by the misfolding and aggregation of toxic protein species, including the amyloid beta (Aß) peptide, microtubule-associated protein Tau (Tau), and alpha-synuclein (αSyn) protein. These factors also show toxicity in Drosophila; however, potential limitations of prior studies include poor discrimination between effects on the adult versus developing nervous system and neuronal versus glial cell types. In addition, variable expression paradigms and outcomes hinder systematic comparison of toxicity profiles. Using standardized conditions and medium-throughput assays, we express human Tau, Aß or αSyn selectively in neurons of the adult Drosophila retina and monitor age-dependent changes in both structure and function, based on tissue histology and recordings of the electroretinogram (ERG), respectively. We find that each protein causes a unique profile of neurodegenerative pathology, demonstrating distinct and separable impacts on neuronal death and dysfunction. Strikingly, expression of Tau leads to progressive loss of ERG responses whereas retinal architecture and neuronal numbers are largely preserved. By contrast, Aß induces modest, age-dependent neuronal loss without degrading the retinal ERG. αSyn expression, using a codon-optimized transgene, is characterized by marked retinal vacuolar change, progressive photoreceptor cell death, and delayed-onset but modest ERG changes. Lastly, to address potential mechanisms, we perform transmission electron microscopy (TEM) to reveal potential degenerative changes at the ultrastructural level. Surprisingly, Tau and αSyn each cause prominent but distinct synaptotoxic profiles, including disorganization or enlargement of photoreceptor terminals, respectively. Our findings highlight variable and dynamic properties of neurodegeneration triggered by these disease-relevant proteins in vivo, and suggest that Drosophila may be useful for revealing determinants of neuronal dysfunction that precede cell loss, including synaptic changes, in the adult nervous system.

Topics: Aging; alpha-Synuclein; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Cell Death; Disease Models, Animal; Drosophila; Electroretinography; Female; Humans; Membrane Potentials; Microelectrodes; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Neurons; Peptide Fragments; Retina; tau Proteins; Vision, Ocular

Synucleinopathy is characterized by abnormal accumulation of misfolded α-synuclein (α-Syn)-positive cytoplasmic inclusions and by neurodegeneration and cognitive impairments, but the pathogenesis mechanism of synucleinopathy remains to be defined. Using a transmission model of synucleinopathy by intracerebral injection of preformed A53T α-Syn fibrils, we investigated whether aberrant adenosine A2A receptor (A2AR) signaling contributed to pathogenesis of synucleinopathy. We demonstrated that intra-hippocampal injection of preformed mutant α-Syn fibrils triggered a striking and selective induction of A2AR expression which was closely co-localized with pSer129 α-Syn-rich inclusions in neurons and glial cells of hippocampus. Importantly, by abolishing aberrant A2AR signaling triggered by mutant α-Syn, genetic deletion of A2ARs blunted a cascade of pathological events leading to synucleinopathy, including pSer129 α-Syn-rich and p62-positive aggregates, NF-κB activation and astrogliosis, apoptotic neuronal cell death and working memory deficits without affecting motor activity. These findings define α-Syn-triggered aberrant A2AR signaling as a critical pathogenesis mechanism of synucleinopathy with dual controls of cognition and neurodegeneration by modulating α-Syn aggregates. Thus, aberrant A2AR signaling represents a useful biomarker as well as a therapeutic target of synucleinopathy.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Cognition Disorders; Disease Models, Animal; Exploratory Behavior; Hippocampus; In Situ Nick-End Labeling; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Neuroglia; Receptor, Adenosine A2A; RNA, Messenger; Signal Transduction

Aggregation of α-synuclein contributes to the formation of Lewy bodies and neurites, the pathologic hallmarks of Parkinson disease (PD) and α-synucleinopathies. Although a number of human mutations have been identified in familial PD, the mechanisms that promote α-synuclein accumulation and toxicity are poorly understood. Here, we report that hyperactivity of the nonreceptor tyrosine kinase c-Abl critically regulates α-synuclein-induced neuropathology. In mice expressing a human α-synucleinopathy-associated mutation (hA53Tα-syn mice), deletion of the gene encoding c-Abl reduced α-synuclein aggregation, neuropathology, and neurobehavioral deficits. Conversely, overexpression of constitutively active c-Abl in hA53Tα-syn mice accelerated α-synuclein aggregation, neuropathology, and neurobehavioral deficits. Moreover, c-Abl activation led to an age-dependent increase in phosphotyrosine 39 α-synuclein. In human postmortem samples, there was an accumulation of phosphotyrosine 39 α-synuclein in brain tissues and Lewy bodies of PD patients compared with age-matched controls. Furthermore, in vitro studies show that c-Abl phosphorylation of α-synuclein at tyrosine 39 enhances α-synuclein aggregation. Taken together, this work establishes a critical role for c-Abl in α-synuclein-induced neurodegeneration and demonstrates that selective inhibition of c-Abl may be neuroprotective. This study further indicates that phosphotyrosine 39 α-synuclein is a potential disease indicator for PD and related α-synucleinopathies.

Topics: Aged; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Female; Gene Deletion; HEK293 Cells; Humans; Lewy Bodies; Male; Mice; Mice, Transgenic; Mutation; Neurites; Neurodegenerative Diseases; Neuroprotection; Parkinson Disease; Phosphorylation; Phosphotyrosine; Proto-Oncogene Proteins c-abl

α-Synuclein (α-Syn), one of the most abundant proteins in the CNS, is known to be a major player in the neurodegeneration observed in Parkinson's disease. We currently report that transient focal ischemia upregulates α-Syn protein expression and nuclear translocation in neurons of the adult rodent brain. We further show that knockdown or knock-out of α-Syn significantly decreases the infarction and promotes better neurological recovery in rodents subjected to focal ischemia. Furthermore, α-Syn knockdown significantly reduced postischemic induction of phospho-Drp1, 3-nitrotyrosine, cleaved caspase-3, and LC-3 II/I, indicating its role in modulating mitochondrial fragmentation, oxidative stress, apoptosis, and autophagy, which are known to mediate poststroke neuronal death. Transient focal ischemia also significantly upregulated serine-129 (S129) phosphorylation (pα-Syn) of α-Syn and nuclear translocation of pα-Syn. Furthermore, knock-out mice that lack PLK2 (the predominant kinase that mediates S129 phosphorylation) showed better functional recovery and smaller infarcts when subjected to transient focal ischemia, indicating a detrimental role of S129 phosphorylation of α-Syn. In conclusion, our studies indicate that α-Syn is a potential therapeutic target to minimize poststroke brain damage.. Abnormal aggregation of α-synuclein (α-Syn) has been known to cause Parkinson's disease and other chronic synucleinopathies. However, even though α-Syn is linked to pathophysiological mechanisms similar to those that produce acute neurodenegerative disorders, such as stroke, the role of α-Syn in such disorder is not clear. We presently studied whether α-Syn mediates poststroke brain damage and more importantly whether preventing α-Syn expression is neuroprotective and leads to better physiological and functional outcome after stroke. Our study indicates that α-Syn is a potential therapeutic target for stroke therapy.

Topics: alpha-Synuclein; Animals; Brain Infarction; Brain Ischemia; Caspase 3; Death-Associated Protein Kinases; Disease Models, Animal; Gene Expression Regulation; Male; Mice; Mice, Transgenic; Microtubule-Associated Proteins; Motor Activity; PC12 Cells; Protein Serine-Threonine Kinases; Rats; Rats, Inbred SHR; RNA, Small Interfering; Stroke; Tyrosine

α-synucleinopathy emerges quite early in olfactory structures such as the olfactory bulb and anterior olfactory nucleus (OB/AON) in Parkinson's disease. This may contribute to smell impairments years before the commencement of motor symptoms. We tested whether α-synucleinopathy can spread from the OB/AON to regions of the limbic telencephalon that harbor connections with olfactory structures.. α-synuclein fibrils were infused into the OB/AON. Inclusions containing pathologically phosphorylated α-synuclein (pSer129) were observed three months later in the piriform and entorhinal cortices, amygdala, and hippocampal formation. The retrograde tract-tracer FluoroGold confirmed the existence of first-order afferents at these sites. Some sites harbored FluoroGold(+) neurons but no inclusions, suggestive of selective vulnerabilities. Multiple areas close to the injection site but not connected with the OB/AON remained free of inclusions, suggesting a lack of widespread uptake of fibrils from interstitial diffusion. Two independent pSer129 antibodies revealed the same labeling patterns and preadsorption control experiments confirmed a loss of pSer129 staining. Dense total α-synuclein (but not pSer129) staining was apparent in the OB/AON 1.5 h following fibril infusions, suggesting that pSer129(+) staining did not reflect exogenously infused material. Waterbath sonication of fibrils for 1 h improved α-synucleinopathy transmission relative to 1 min-long probe sonication. Electron microscopy revealed that longer sonication durations reduced fibril size. The Thioflavin stain labeled cells at the infusion site and some, but not all inclusions contained ubiquitin. Three-dimensional confocal analyses revealed that many inclusions ensconced NeuN(+) neuronal nuclei. Young and aged mice exhibited similar topographical spread of α-synucleinopathy.. 1) α-synucleinopathy in this model is transmitted through some, but not all neuroanatomical connections, 2) pathology is largely confined to first-order afferent sites at three months and this is most parsimoniously explained by retrograde transport, and 3) transmission in aged animals is largely similar to that in young control animals at three months post-infusion.

Topics: alpha-Synuclein; Animals; Axonal Transport; Disease Models, Animal; Mice; Olfactory Bulb; Olfactory Cortex; Parkinsonian Disorders; Temporal Lobe

α-Synuclein (α-Syn) has a critical role in microglia-mediated neuroinflammation, which leads to the development of Parkinson's disease (PD). Recent studies have shown that bee venom (BV) has beneficial effects on PD symptoms in human patients or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxin-induced PD mice. This study investigated whether treatment with BV-derived phospholipase A2 (bvPLA2) would improve the motor dysfunction and pathological features of PD in human A53T α-Syn mutant transgenic (A53T Tg) mice. The motor dysfunction of A53T Tg mice was assessed using the pole test. The levels of α-Syn, microglia and the M1/M2 phenotype in the spinal cord were evaluated by immunofluorescence. bvPLA2 treatment significantly ameliorated motor dysfunction in A53T Tg mice. In addition, bvPLA2 significantly reduced the expression of α-Syn, the activation and numbers of microglia, and the ratio of M1/M2 in A53T Tg mice. These results suggest that bvPLA2 could be a promising treatment option for PD.

Topics: alpha-Synuclein; Animals; Bee Venoms; Bees; Disease Models, Animal; Enzyme Therapy; Humans; Mice; Mice, Transgenic; Microglia; Motor Activity; Parkinson Disease; Phospholipases A2; Point Mutation; Spinal Cord

Abnormal α-synuclein (α-syn) accumulation in the CNS may underlie neuronal cell and synaptic dysfunction leading to motor and cognitive deficits in synucleinopathies including Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB). Multiple groups demonstrated α-syn accumulation in CNS accessory structures, including the eyes and olfactory terminals, as well as in peripheral organs of Parkinsonian patients. Retinal imaging studies of mice overexpressing fused α-syn::GFP were conducted to evaluate the presence and progression of retinal pathology in a PD/DLB transgenic mouse model. Bright-field image retinal maps and fluorescent images were acquired at 1-month intervals for 3 months. Retinal imaging revealed the accumulation of GFP-tagged α-syn in retinal ganglion cell layer and in the edges of arterial blood vessels in the transgenic mice. Double labeling studies confirmed that the α-syn::GFP-positive cells were retinal ganglion cells containing α-syn. Accumulation of α-syn persisted in the same cells and increased with age. Accumulation of α-syn::GFP was reduced by immunization with single chain antibodies against α-syn. In conclusion, longitudinal live imaging of the retina in the PDGF-α-syn::GFP mice might represent a useful, non-invasive tool to monitor the fate of α-syn accumulation in the CNS and to evaluate the therapeutic effects of compounds targeting α-syn.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Disease Progression; Green Fluorescent Proteins; Humans; Immunotherapy; Lewy Body Disease; Male; Mice; Mice, Transgenic; Optical Imaging; Parkinson Disease; Recombinant Fusion Proteins; Retina; Retinal Ganglion Cells; Single-Chain Antibodies

Numerous long non-coding RNAs (lncRNA) have been identified in neurodegenerative disorders including Parkinson's disease (PD). Emerging evidence demonstrates that β-asarone functions as neuroprotective effects in both in vitro and in vivo models. However, the role of β-asarone and its potential mechanism in PD remain not completely clear.. MPTP-induced PD mouse model and SH-SY5Y cells subjected to MPP+ as its in vitro model were used to evaluate the effects of β-asarone on PD. LncRNA MALAT1 and α-synuclein expression were determined by real-time PCR and western blot methods.. β-Asarone significantly increased the TH+ cells number and decreased the expression levels of MALAT1 and α-synuclein in midbrain tissue of PD mice. RNA pull-down and immunoprecipitation assays confirmed that MALAT1 associated with α-synuclein, leading to the increased stability of α-synuclein and its expression in SH-SY5Y cells. β-asarone elevated the viability of cells exposed to MPP+. Either overexpressed MALAT1 or α-synuclein could canceled the protective effect of β-asarone on cell viability. In PD mice, pcDNA-MALAT1 also decreased the TH+ cells number and increased the α-synuclein expression in PD mice with treatment of β-asarone.. β-Asarone functions as a neuroprotective effect in both in vivo and in vitro models of PD via regulating MALAT1 and α-synuclein expression.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Allylbenzene Derivatives; alpha-Synuclein; Animals; Anisoles; Cell Line, Tumor; Cell Survival; Disease Models, Animal; Humans; Male; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Parkinson Disease; RNA, Long Noncoding; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a progressive neurodegenerative disease that affects ∼5 million people around the world. PD etiopathogenesis is poorly understood and curative or disease modifying treatments are not available. Mechanistic studies have identified numerous pathogenic pathways that overlap with many other neurodegenerative diseases. Mutations in the protein optineurin (OPTN) have recently been identified as causative factors for glaucoma and amyotrophic lateral sclerosis. OPTN has multiple recognized roles in neurons, notably in mediating autophagic flux, which has been found to be disrupted in most neurodegenerative diseases. OPTN(+ )aggregates have preliminarily been identified in cytoplasmic inclusions in numerous neurodegenerative diseases, however, whether OPTN has a role in PD pathogenesis has yet to be tested. Thus, we chose to test the hypothesis that OPTN expression and localization would be modulated in pre-clinical PD models. To test our hypothesis, we characterized midbrain OPTN expression in normal rats and in a rat rotenone PD model. For the first time, we show that OPTN is enriched in dopamine neurons in the midbrain, and its expression is modulated by rotenone treatment in vivo Here, animals were sampled at time-points both prior to overt neurodegeneration and after severe behavioral deficits, where a lesion to the nigrostriatal dopamine system is present. The effect and magnitude of OPTN expression changes are dependent on duration of treatment. Furthermore, OPTN colocalizes with LC3 (autophagic vesicle marker) and alpha-synuclein positive puncta in rotenone-treated animals, potentially indicating an important role in autophagy and PD pathogenesis.

Topics: alpha-Synuclein; Animals; Autophagy; Cell Cycle Proteins; Corpus Striatum; Disease Models, Animal; Membrane Transport Proteins; Mesencephalon; Parkinson Disease; Rats; Rats, Inbred Lew; Rotenone; Substantia Nigra; Transcription Factor TFIIIA

Multiple system atrophy (MSA) is a sporadic orphan neurodegenerative disorder. No treatment is currently available to slow down the aggressive neurodegenerative process, and patients die within a few years after disease onset. The cytopathological hallmark of MSA is the accumulation of alpha-synuclein (α-syn) aggregates in affected oligodendrocytes. Several studies point to α-syn oligomerization and aggregation as a mediator of neurotoxicity in synucleinopathies including MSA. C-terminal truncation by the inflammatory protease caspase-1 has recently been implicated in the mechanisms that promote aggregation of α-syn in vitro and in neuronal cell models of α-syn toxicity. We present here an in vivo proof of concept of the ability of the caspase-1 inhibitor prodrug VX-765 to mitigate α-syn pathology and to mediate neuroprotection in proteolipid protein α-syn (PLP-SYN) mice, a transgenic mouse model of MSA. PLP-SYN and age-matched wild-type mice were treated for a period of 11 wk with VX-765 or placebo. VX-765 prevented motor deficits in PLP-SYN mice compared with placebo controls. More importantly, VX-765 was able to limit the progressive toxicity of α-syn aggregation by reducing its load in the striatum of PLP-SYN mice. Not only did VX-765 reduce truncated α-syn, but it also decreased its monomeric and oligomeric forms. Finally, VX-765 showed neuroprotective effects by preserving tyrosine hydroxylase-positive neurons in the substantia nigra of PLP-SYN mice. In conclusion, our results suggest that VX-765, a drug that was well tolerated in a 6 wk-long phase II trial in patients with epilepsy, is a promising candidate to achieve disease modification in synucleinopathies by limiting α-syn accumulation.

Topics: alpha-Synuclein; Animals; Caspase 1; Clinical Trials as Topic; Corpus Striatum; Dipeptides; Disease Models, Animal; Gene Expression Regulation; Humans; Mice; Mice, Transgenic; Multiple System Atrophy; Neurons; Oligodendroglia; para-Aminobenzoates; Protein Aggregates; Proteolysis; Signal Transduction; Substantia Nigra; Tyrosine 3-Monooxygenase

Aging is the major risk factor for neurodegenerative diseases that are also associated with impaired proteostasis, resulting in abnormal accumulation of protein aggregates. However, the role of aging in development and progression of disease remains elusive. Here, we used Caenorhabditis elegans models to show that aging-promoting genetic variations accelerated the rate of cell-to-cell transmission of SNCA/α-synuclein aggregates, hallmarks of Parkinson disease, and the progression of disease phenotypes, such as nerve degeneration, behavioral deficits, and reduced life span. Genetic and pharmacological anti-aging manipulations slowed the spread of aggregates and the associated phenotypes. Lysosomal degradation was significantly impaired in aging models, while anti-aging treatments reduced the impairment. Transgenic expression of hlh-30p::hlh-30, the master controller of lysosomal biogenesis, alleviated intercellular transmission of aggregates in the aging model. Our results demonstrate that the rate of aging closely correlates with the rate of aggregate propagation and that general anti-aging treatments can slow aggregate propagation and associated disease progression by restoring lysosomal function.

Topics: Acetylglucosamine; Aging; alpha-Synuclein; Animals; Caenorhabditis elegans; Disease Models, Animal; Endosomes; Humans; Lysosomes; Mutation; Polyubiquitin; Protein Aggregates; Transgenes; Ubiquitination

Microglia in the brain show distinctive phenotypes that serve different functions. In particular, M2-polarized microglia are anti-inflammatory and phagocytic cells that serve a restorative function. In this study, we investigated whether mesenchymal stem cells (MSCs) enhance the phagocytic clearance of α-synuclein via M2 microglia polarization, and thereby exert neuroprotective effects in α-synuclein-enriched experimental models and patients with multiple system atrophy (MSA). Treatment of BV2 cells with α-synuclein induced an inflammatory phenotype, whereas co-culture of α-synuclein-treated BV2 cells with MSCs induced an anti-inflammatory M2 phenotype, with decreased α-synuclein levels and increased lysosomal activity, leading to greater viability of neuronal cells co-cultured with BV2 cells. Using IL-4 receptor siRNA in BV2 cells and IL-4 siRNA in MSCs, we found that M2 microglia polarization was induced by IL-4 secreted from MSCs. In α-synuclein-inoculated mice, MSC treatment induced M2 microglia polarization decreased α-synuclein levels, and had a prosurvival effect on neurons. Using IL-4 and IL-4 receptor knockout mice, we further confirmed that IL-4 secreted from MSCs induced phagocytic clearance of α-synuclein through M2 microglia polarization. Next, we found that the cerebrospinal fluid (CSF) from MSC-transplanted MSA patients induced microglia M2 polarization and had a prosurvival effect via enhanced clearance of α-synuclein in α-synuclein-treated BV2 cells. Finally, a serial CSF study demonstrated that changes in oligomeric α-synuclein from baseline to 1-year follow-up were greater in the CSF of MSC-transplanted MSA patients than in placebo-transplanted MSA patients. These findings indicate that MSCs exert a neuroprotective effect via the clearance of extracellular α-synuclein by controlling microglia M2 polarization, suggesting that MSCs could be used as a disease-modifying therapy for patients with α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Cell Line; Cell Polarity; Coculture Techniques; Cytokines; Disease Models, Animal; Gene Expression Regulation; Humans; Interleukin-4; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Multiple System Atrophy; Neuroprotective Agents; Parkinsonian Disorders; Phosphopyruvate Hydratase

Parkinson's disease (PD) is characterized by the progressive appearance of intraneuronal Lewy aggregates, which are primarily composed of misfolded α-synuclein (α-syn). The aggregates are believed to propagate via neural pathways following a stereotypical pattern, starting in the olfactory bulb (OB) and gut. We hypothesized that injection of fibrillar α-syn into the OB of wild-type mice would recreate the sequential progression of Lewy-like pathology, while triggering olfactory deficits. We demonstrate that injected α-syn fibrils recruit endogenous α-syn into pathological aggregates that spread transneuronally over several months, initially in the olfactory network and later in distant brain regions. The seeded inclusions contain posttranslationally modified α-syn that is Thioflavin S positive, indicative of amyloid fibrils. The spreading α-syn pathology induces progressive and specific olfactory deficits. Thus, we demonstrate that propagating α-syn pathology triggered in the OB is functionally detrimental. Collectively, we have created a mouse model of prodromal PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Disease Progression; Female; Lewy Bodies; Mice; Mice, Inbred C57BL; Neural Pathways; Olfactory Bulb; Olfactory Tubercle; Parkinson Disease; Protein Aggregation, Pathological

Increasing evidence points to defects in autophagy as a common denominator in most neurodegenerative conditions. Progressive functional decline in the autophagy-lysosomal pathway (ALP) occurs with age, and the consequent impairment in protein processing capacity has been associated with a higher risk of neurodegeneration. Defects in cathepsin D (CD) processing and α-synuclein degradation causing its accumulation in lysosomes are particularly relevant for the development of Parkinson's disease (PD). However, the mechanism by which alterations in CD maturation and α-synuclein degradation leads to autophagy defects in PD neurons is still uncertain. Here we demonstrate that MPR300 shuttling between endosomes and the trans Golgi network is altered in α-synuclein overexpressing neurons. Consequently, CD is not correctly trafficked to lysosomes and cannot be processed to generate its mature active form, leading to a reduced CD-mediated α-synuclein degradation and α-synuclein accumulation in neurons. MPR300 is downregulated in brain from α-synuclein overexpressing animal models and in PD patients with early diagnosis. These data indicate MPR300 as crucial player in the autophagy-lysosomal dysfunctions reported in PD and pinpoint MRP300 as a potential biomarker for PD.

Topics: Aged; alpha-Synuclein; Animals; Autophagy; Biomarkers; Brain; Cathepsin D; Cell Line, Tumor; Disease Models, Animal; Down-Regulation; Female; Humans; Lysosomes; Male; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Parkinson Disease; Receptor, IGF Type 2; RNA, Messenger; trans-Golgi Network

Increased α-synuclein immunoreactivity has been associated with inflammatory activity in multiple sclerosis (MS) lesions, but the function of α-synuclein in neuroinflammation remains unknown. The aim of this study was to examine the role of α-synuclein in immunological processes in murine experimental autoimmune encephalomyelitis (EAE) as a model of MS.. We studied EAE in wildtype (aSyn(+/+)) and α-synuclein knockout (aSyn(-/-)) mice on a C57BL/6N background. In the spleen and spinal cord of aSyn(+/+) mice, we observed a gradual reduction of α-synuclein expression during EAE, starting already in the pre-symptomatic disease phase. Compared to aSyn(+/+) mice, aSyn(-/-) mice showed an earlier onset of symptoms but no differences in symptom severity at the peak of disease. Earlier symptom onset was accompanied by increased spinal cord infiltration of CD4(+) T cells, predominantly of interferon-γ-producing T helper 1 (Th1) cells, and reduced infiltration of regulatory T cells, whereas antigen-presenting cells were unaltered. Pre-symptomatically, aSyn(-/-) mice exhibited hyperproliferative CD4(+) splenocytes consistent with increased splenic interleukin-2 mRNA expression, resulting in increased numbers of Th1 cells in the spleen at the onset of symptoms.. Our findings indicate a functional role of α-synuclein in early EAE by increasing Th1 cell-mediated immune response.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Antigen-Presenting Cells; Cell Proliferation; Cytokines; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Gene Expression Regulation; Mice; Mice, Inbred C57BL; Myelin-Oligodendrocyte Glycoprotein; Peptide Fragments; RNA, Messenger; Spinal Cord; Th1 Cells

To study the neuronal deficits in neuronopathic Gaucher Disease (nGD), the chronological behavioral profiles and the age of onset of brain abnormalities were characterized in a chronic nGD mouse model (9V/null). Progressive accumulation of glucosylceramide (GC) and glucosylsphingosine (GS) in the brain of 9V/null mice were observed at as early as 6 and 3 months of age for GC and GS, respectively. Abnormal accumulation of α-synuclein was present in the 9V/null brain as detected by immunofluorescence and Western blot analysis. In a repeated open-field test, the 9V/null mice (9 months and older) displayed significantly less environmental habituation and spent more time exploring the open-field than age-matched WT group, indicating the onset of short-term spatial memory deficits. In the marble burying test, the 9V/null group had a shorter latency to initiate burying activity at 3 months of age, whereas the latency increased significantly at ≥12 months of age; 9V/null females buried significantly more marbles to completion than the WT group, suggesting an abnormal response to the instinctive behavior and an abnormal activity in non-associative anxiety-like behavior. In the conditional fear test, only the 9V/null males exhibited a significant decrease in response to contextual fear, but both genders showed less response to auditory-cued fear compared to age- and gender-matched WT at 12 months of age. These results indicate hippocampus-related emotional memory defects. Abnormal gait emerged in 9V/null mice with wider front-paw and hind-paw widths, as well as longer stride in a gender-dependent manner with different ages of onset. Significantly higher liver- and spleen-to-body weight ratios were detected in 9V/null mice with different ages of onsets. These data provide temporal evaluation of neurobehavioral dysfunctions and brain pathology in 9V/null mice that can be used for experimental designs to evaluate novel therapies for nGD.

Topics: Acoustic Stimulation; Aging; alpha-Synuclein; Animals; Behavior, Animal; Conditioning, Psychological; Disease Models, Animal; Disease Progression; Exploratory Behavior; Fear; Female; Gait; Gaucher Disease; Glucosylceramidase; Glucosylceramides; Hippocampus; Male; Memory Disorders; Mice; Psychosine; Sex Factors; Spatial Memory

Parkinson's disease (PD) is characterized by the progressive degeneration of the dopaminergic neurons in the substantia nigra (SN) region. Acteoside has displayed multiple biological functions. Its potential role against PD and the underlying signaling mechanisms are largely unknown. Here, we showed that oral administration of acteoside significantly attenuated parkinsonism symptoms in rotenone-induced PD rats. Further, acteoside inhibited rotenone-induced α-synuclein, caspase-3 upregulation and microtubule-associated protein 2 (MAP2) downregulation in PD rats. The molecular docking and molecular dynamics (MD) simulation results indicated that acteoside may directly bind to and inhibit caspase-3. Acteoside formed hydrogen bonds with at least six residues of caspase-3: ThrA177, SerA178, GlyA238, SerB339, ArgB341 and TrpB348. In addition, a pi-pi interaction was formed between acteoside and caspase-3's HisA237, which might further stabilize the complex. MD simulation results demonstrated that the binding affinity of the caspase-3-acteoside complex was higher than that of caspase-3 and its native ligand inhibitor. Together, we show that acteoside binds to caspase-3 and exerts neuroprotection in the rotenone rat model of PD.

Topics: alpha-Synuclein; Animals; Caspase 3; Disease Models, Animal; Glucosides; Humans; Microtubule-Associated Proteins; Molecular Dynamics Simulation; Parkinson Disease; Phenols; Protein Binding; Rats; Rats, Sprague-Dawley; Rotenone

Abnormal accumulation and propagation of the neuronal protein α-synuclein has been hypothesized to underlie the pathogenesis of Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Here we report a de novo-developed compound (NPT100-18A) that reduces α-synuclein toxicity through a novel mechanism that involves displacing α-synuclein from the membrane. This compound interacts with a domain in the C-terminus of α-synuclein. The E83R mutation reduces the compound interaction with the 80-90 amino acid region of α-synuclein and prevents the effects of NPT100-18A. In vitro studies showed that NPT100-18A reduced the formation of wild-type α-synuclein oligomers in membranes, reduced the neuronal accumulation of α-synuclein, and decreased markers of cell toxicity. In vivo studies were conducted in three different α-synuclein transgenic rodent models. Treatment with NPT100-18A ameliorated motor deficits in mThy1 wild-type α-synuclein transgenic mice in a dose-dependent manner at two independent institutions. Neuropathological examination showed that NPT100-18A decreased the accumulation of proteinase K-resistant α-synuclein aggregates in the CNS and was accompanied by the normalization of neuronal and inflammatory markers. These results were confirmed in a mutant line of α-synuclein transgenic mice that is prone to generate oligomers. In vivo imaging studies of α-synuclein-GFP transgenic mice using two-photon microscopy showed that NPT100-18A reduced the cortical synaptic accumulation of α-synuclein within 1 h post-administration. Taken together, these studies support the notion that altering the interaction of α-synuclein with the membrane might be a feasible therapeutic approach for developing new disease-modifying treatments of Parkinson's disease and other synucleinopathies.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Behavior, Animal; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Discovery; Humans; Mice; Mice, Transgenic; Parkinson Disease

Cell physiology is impaired before protein aggregation and this may be more relevant than inclusions themselves for neurodegeneration. The present study aimed to characterize an animal model to enable the analysis of the cell biology before and after protein aggregation. Ten-month-old Lewis rats were exposed either to 1 or 2 mg/kg/day of rotenone, delivered subcutaneously through mini-pumps, for one month. Hyperphosphorylated TAU, alpha-synuclein, amyloid-beta peptide and protein carbonylation (indicative of oxidative stress) were evaluated in the hippocampus, substantia nigra and locus coeruleus through immunohistochemistry or western blot. It was found that 2 mg/kg/day rotenone increased amyloid-beta peptide, hyperphosphorylation of TAU and alpha-synuclein. Rotenone at 1mg/kg/day did not alter protein levels. Protein carbonylation remained unchanged. This study demonstrated that aged Lewis rats exposed to a low dose of rotenone is a useful model to study cellular processes before protein aggregation, while the higher dose makes a good model to study the effects of protein inclusions.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Blotting, Western; Central Nervous System; Disease Models, Animal; Hippocampus; Immunohistochemistry; Locus Coeruleus; Male; Oxidative Stress; Parkinson Disease; Protein Aggregation, Pathological; Protein Carbonylation; Rats, Inbred Lew; Reproducibility of Results; Rotenone; Substantia Nigra

We have been investigating the role that phosphatidylethanolamine (PE) and phosphatidylcholine (PC) content plays in modulating the solubility of the Parkinson's disease protein alpha-synuclein (α-syn) using Saccharomyces cerevisiae and Caenorhabditis elegans. One enzyme that synthesizes PE is the conserved enzyme phosphatidylserine decarboxylase (Psd1/yeast; PSD-1/worms), which is lodged in the inner mitochondrial membrane. We previously found that decreasing the level of PE due to knockdown of Psd1/psd-1 affects the homeostasis of α-syn in vivo. In S. cerevisiae, the co-occurrence of low PE and α-syn in psd1Δ cells triggers mitochondrial defects, stress in the endoplasmic reticulum, misprocessing of glycosylphosphatidylinositol-anchored proteins, and a 3-fold increase in the level of α-syn. The goal of this study was to identify drugs that rescue this phenotype. We screened the Prestwick library of 1121 Food and Drug Administration-approved drugs using psd1Δ + α-syn cells and identified cyclosporin A, meclofenoxate hydrochloride, and sulfaphenazole as putative protective compounds. The protective activity of these drugs was corroborated using C. elegans in which α-syn is expressed specifically in the dopaminergic neurons, with psd-1 depleted by RNAi. Worm populations were examined for dopaminergic neuron survival following psd-1 knockdown. Exposure to cyclosporine, meclofenoxate, and sulfaphenazole significantly enhanced survival at day 7 in α-syn-expressing worm populations whereby 50-55% of the populations displayed normal neurons, compared to only 10-15% of untreated animals. We also found that all three drugs rescued worms expressing α-syn in dopaminergic neurons that were deficient in the phospholipid cardiolipin following cardiolipin synthase (crls-1) depletion by RNAi. We discuss how these drugs might block α-syn pathology in dopaminergic neurons.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Carboxy-Lyases; Cyclosporine; Disease Models, Animal; Dopaminergic Neurons; Endoplasmic Reticulum Stress; Meclofenoxate; Membrane Proteins; Mitochondria; Mitochondrial Proteins; Parkinson Disease; Phosphatidylcholines; Phosphatidylethanolamines; Protective Agents; Saccharomyces cerevisiae; Solubility; Sulfaphenazole; Transferases (Other Substituted Phosphate Groups)

The incidence of preterm birth is rising worldwide. Among preterm infants, many face a lifetime of neurologic impairments. Recent studies have revealed that systemic inflammation can sensitize the immature brain to hypoxic-ischemic (HI) injury. Therefore, it is important to identify the mechanisms involved in inflammation-sensitized HI injury in immature brains. PTEN-induced putative kinase 1 (PINK1) is a regulatory protein that is highly expressed in the brain. We have previously found that PINK1 gene knockout can protect matured brains from HI injury in postnatal day 10 mice. However, the mechanisms are unknown. In this study, we employed an inflammation-sensitized HI injury model using postnatal day 3 mice to study the roles and mechanisms that PINK1 plays in the immature brains. Lipopolysaccharide (LPS) was injected intraperitoneally into the mice before HI treatment to set up the model. We found that PINK1-knockout mice had fewer brain infarcts and less cell apoptosis than did the wild-type mice. Furthermore, we found that α-synuclein was markedly higher in the PINK1-knockout mice than in the wild-type mice, and inhibition of α-synuclein through small interfering RNA (siRNA) reversed the protective effect in the PINK1-knockout mice. Collectively, these findings indicate that loss of PINK1 plays a novel role in the protection of inflammation-sensitized HI brain damage.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Apoptosis; Brain; Disease Models, Animal; Female; Hypoxia-Ischemia, Brain; Lipopolysaccharides; Male; Mice, Inbred C57BL; Mice, Knockout; Neuroimmunomodulation; Neurons; Neuroprotection; Protein Kinases; Random Allocation; Repressor Proteins; RNA, Small Interfering; Tumor Suppressor Proteins

Evaluation of motor deficits in rodents is mostly restricted to limb motor tests that are often high stressors for the animals.. To test rodents for orofacial motor impairments in a stress-free environment, we established the pasta gnawing test by measuring the biting noise of mice that eat a piece of spaghetti. Two parameters were evaluated, the biting speed and the biting peaks per biting episode. To evaluate the power of this test compared to commonly used limb motor and muscle strength tests, three mouse models of Parkinson's disease, amyotrophic lateral sclerosis and Niemann-Pick disease were tested in the pasta gnawing test, RotaRod and wire suspension test.. Our results show that the pasta gnawing test reliably displays orofacial motor deficits.. The test is especially useful as additional motor test in early onset disease models, since it shows first deficits later than the RotaRod or wire suspension test. The test depends on a voluntary eating behavior of the animal with only a short-time food deprivation and should thus be stress-free.. The pasta gnawing test represents a valuable tool to analyze orofacial motor deficits in different early onset disease models.

Topics: alpha-Synuclein; Amyotrophic Lateral Sclerosis; Animals; Craniofacial Abnormalities; Disease Models, Animal; DNA-Binding Proteins; Exercise Test; Humans; Intracellular Signaling Peptides and Proteins; Mastication; Mice; Mice, Transgenic; Motor Activity; Muscle Strength; Niemann-Pick C1 Protein; Niemann-Pick Diseases; Parkinson Disease; Proteins; Psychomotor Performance; Reaction Time; Rotarod Performance Test; Statistics, Nonparametric

Several neurodegenerative diseases are driven by the toxic gain-of-function of specific proteins within the brain. Elevated levels of alpha-synuclein (α-Syn) appear to drive neurotoxicity in Parkinson's disease (PD); neuronal accumulation of tau is a hallmark of Alzheimer's disease (AD); and their increased levels cause neurodegeneration in humans and model organisms. Despite the clinical differences between AD and PD, several lines of evidence suggest that α-Syn and tau overlap pathologically. The connections between α-Syn and tau led us to ask whether these proteins might be regulated through a shared pathway. We therefore screened for genes that affect post-translational levels of α-Syn and tau. We found that TRIM28 regulates α-Syn and tau levels and that its reduction rescues toxicity in animal models of tau- and α-Syn-mediated degeneration. TRIM28 stabilizes and promotes the nuclear accumulation and toxicity of both proteins. Intersecting screens across comorbid proteinopathies thus reveal shared mechanisms and therapeutic entry points.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Cell Nucleus; Cells, Cultured; Disease Models, Animal; Humans; Mice; Parkinson Disease; tau Proteins; Tripartite Motif-Containing Protein 28

Autophagy is a cellular mechanism implicated in the pathology of Parkinson's disease. The proteins Atg6 (Beclin 1) and Pi3K59F are involved in autophagosome formation, a key step in the initiation of autophagy. We first used the GMR-Gal4 driver to determine the effect of reducing the expression of the genes encoding these proteins on the developing Drosophila melanogaster eye. Subsequently, we inhibited their expression in D. melanogaster neurons under the direction of a Dopa decarboxylase (Ddc) transgene, and examined the effects on longevity and motor function. Decreased longevity coupled with an age-dependent loss of climbing ability was observed. In addition, we investigated the roles of these genes in the well-studied α-synuclein-induced Drosophila model of Parkinson's disease. In this context, lowered expression of Atg6 or Pi3K59F in Ddc-Gal4-expressing neurons results in decreased longevity and associated age-dependent loss of locomotor ability. Inhibition of Atg6 or Pi3K59F together with overexpression of the sole pro-survival Bcl-2 Drosophila homolog Buffy in Ddc-Gal4-expressing neurons resulted in further decrease in the survival and climbing ability of Atg6-RNAi flies, whereas these measures were ameliorated in Pi3K59F-RNAi flies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Beclin-1; Disease Models, Animal; Dopa Decarboxylase; Drosophila melanogaster; Drosophila Proteins; Eye; Gene Expression Regulation, Developmental; Humans; Longevity; Motor Activity; Neurons; Parkinson Disease; RNA Interference

Gaucher disease is caused by mutations in the glucocerebrosidase 1 gene that result in deficiency of the lysosomal enzyme glucocerebrosidase. Both homozygous and heterozygous glucocerebrosidase 1 mutations confer an increased risk for developing Parkinson disease. Current estimates indicate that 10 to 25% of Parkinson patients carry glucocerebrosidase 1 mutations. Ambroxol is a small molecule chaperone that has been shown to increase glucocerebrosidase activity in vitro. This study investigated the effect of ambroxol treatment on glucocerebrosidase activity and on α-synuclein and phosphorylated α-synuclein protein levels in mice.. Mice were treated with ambroxol for 12 days. After the treatment, glucocerebrosidase activity was measured in the mouse brain lysates. The brain lysates were also analyzed for α-synuclein and phosphorylated α-synuclein protein levels.. Ambroxol treatment resulted in increased brain glucocerebrosidase activity in (1) wild-type mice, (2) transgenic mice expressing the heterozygous L444P mutation in the murine glucocerebrosidase 1 gene, and (3) transgenic mice overexpressing human α-synuclein. Furthermore, in the mice overexpressing human α-synuclein, ambroxol treatment decreased both α-synuclein and phosphorylated α-synuclein protein levels.. Our work supports the proposition that ambroxol should be further investigated as a potential novel disease-modifying therapy for treatment of Parkinson disease and neuronopathic Gaucher disease to increase glucocerebrosidase activity and decrease α-synuclein and phosphorylated α-synuclein protein levels. Ann Neurol 2016;80:766-775.

Topics: alpha-Synuclein; Ambroxol; Animals; Brain; Disease Models, Animal; Expectorants; Gaucher Disease; Glucosylceramidase; Humans; Mice; Mice, Transgenic; Parkinson Disease

Recent failures in clinical trials for disease modification in Parkinson's disease have highlighted the need for a non-human primate model of the synucleinopathy underpinning dopaminergic neuron degeneration. The present study was defined to begin the development of such a model in cynomolgus macaque. We have validated surgical and vector parameters to define a means to provide a robust over-expression of alpha-synuclein which is associated with Lewy-like pathology and robust degeneration of the nigrostriatal pathway. Thus, an AAV1/2 vector incorporating strong transcription and transduction regulatory elements was used to deliver the gene for the human A53T mutation of alpha-synuclein. When injected into 4 sites within each substantia nigra (7 μl per site, 1.7 x 1012 gp/ml), this vector provided expression lasting at least 4 months, and a 50% loss of nigral dopaminergic neurons and a 60% reduction in striatal dopamine. Further studies will be required to develop this methodology into a validated model of value as a drug development platform.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Female; Gene Expression; Genetic Therapy; Genetic Vectors; Humans; Macaca; Neostriatum; Parkinson Disease

Aggregation of alpha synuclein (α-syn) leading to dopaminergic neuronal death has been recognized as one of the main pathogenic factors in the initiation and progression of Parkinson's disease (PD). Consequently, α-syn has been targeted for the development of therapeutics for PD. We have developed a novel assay to screen compounds with α-syn modulating properties by mimicking recent findings from in vivo animal studies involving intrastriatal administration of pre-formed fibrils in mice, resulting in increased α-syn pathology accompanying the formation of Lewy-body (LB) type inclusions. We found that in vitro generated α-syn pre-formed fibrils induce seeding of α-syn monomers to produce aggregates in a dose-and time-dependent manner under static conditions in vitro. These aggregates were toxic towards rat pheochromocytoma cells (PC12). Our novel multifunctional dopamine agonists D-519 and D-520 exhibited significant neuroprotection in this assay, while their parent molecules did not. The neuroprotective properties of our compounds were further evaluated in a Drosophila model of synucleinopathy. Both of our compounds showed protective properties in fly eyes against the toxicity caused by α-syn. Thus, our in vitro results on modulation of aggregation and toxicity of α-syn by our novel assay were further validated with the in vivo experiments.

Topics: alpha-Synuclein; Animals; Benzothiazoles; Biological Assay; Circular Dichroism; Disease Models, Animal; Dopamine Agonists; Drosophila melanogaster; Eye; PC12 Cells; Pramipexole; Protein Aggregates; Protein Structure, Secondary; Rats; Rifampin; Tetrahydronaphthalenes

Mitochondrial and autophagic dysfunction as well as neuroinflammation are involved in the pathophysiology of Parkinson's disease (PD). We hypothesized that targeting the mitochondrial pyruvate carrier (MPC), a key controller of cellular metabolism that influences mTOR (mammalian target of rapamycin) activation, might attenuate neurodegeneration of nigral dopaminergic neurons in animal models of PD. To test this, we used MSDC-0160, a compound that specifically targets MPC, to reduce its activity. MSDC-0160 protected against 1-methyl-4-phenylpyridinium (MPP

Topics: 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Brain; Caenorhabditis elegans; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Heterozygote; Humans; Inflammation; Male; Mice; Mice, Inbred C57BL; Mitochondria; Neurodegenerative Diseases; Neurons; Oxygen Consumption; Parkinson Disease; Pyridines; Pyruvic Acid; Signal Transduction; Substantia Nigra; Thiazolidinediones

The common age-related neurodegeneration of Parkinson's disease can result from dominant causes like increased dosage of vesicle-associated alpha-synuclein (SNCA) or recessive causes like deficiency of mitophagy factor PINK1. Interactions between these triggers and their convergence onto shared pathways are crucial, but currently conflicting evidence exists. Here, we crossed previously characterized mice with A53T-SNCA overexpression and with Pink1 deletion to generate double mutants (DMs). We studied their lifespan and behavior, histological and molecular anomalies at late and early ages. DM animals showed potentiated phenotypes in comparison with both single mutants (SMs), with reduced survival and strongly reduced spontaneous movements from the age of 3 months onwards. In contrast to SMs, a quarter of DM animals manifested progressive paralysis at ages >1 year and exhibited protein aggregates immunopositive for pSer129-SNCA, p62 and ubiquitin in spinal cord and basal brain. Brain proteome quantifications of ubiquitination sites documented altered degradation of SNCA and the DNA-damage marker H2AX at the age of 18 months. Global brain transcriptome profiles and qPCR validation experiments identified many consistent transcriptional dysregulations already at the age of 6 weeks, which were absent from SMs. The observed downregulations for Dapk1, Dcaf17, Rab42 and the novel SNCA-marker Lect1 as well as the upregulations for Dctn5, Mrpl9, Tmem181a, Xaf1 and H2afx reflect changes in ubiquitination, mitochondrial/synaptic/microtubular/cell adhesion dynamics and DNA damage. Thus, our study confirmed that SNCA-triggered neurotoxicity is exacerbated by the absence of PINK1 and identified a novel molecular signature that is detectable early in the course of this double pathology.

Topics: Age Factors; alpha-Synuclein; Animals; Brain; Computational Biology; Disease Models, Animal; Female; Gene Expression; Gene Expression Profiling; Male; Mesencephalon; Mice; Mice, Knockout; Motor Activity; Mutation; Parkinson Disease; Phenotype; Protein Kinases; Spinal Cord; Transcriptome

Alpha-synuclein (SNCA) protein aggregation plays a causal role in Parkinson's disease (PD). The SNCA protein modulates neurotransmission via the SNAP receptor (SNARE) complex assembly and presynaptic vesicle trafficking. The striatal presynaptic dopamine deficit is alleviated by treatment with levodopa (L-DOPA), but postsynaptic plastic changes induced by this treatment lead to a development of involuntary movements (dyskinesia). While this process is currently modeled in rodents harboring neurotoxin-induced lesions of the nigrostriatal pathway, we have here explored the postsynaptic supersensitivity of dopamine receptor-mediated signaling in a genetic mouse model of early PD. To this end, we used mice with prion promoter-driven overexpression of A53T-SNCA in the nigrostriatal and corticostriatal projections. At a symptomatic age (18 months), mice were challenged with apomorphine (5 mg/kg s.c.) and examined using both behavioral and molecular assays. After the administration of apomorphine, A53T-transgenic mice showed more severe stereotypic and dystonic movements in comparison with wild-type controls. Molecular markers of extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation and dephosphorylation, and Fos messenger RNA (mRNA), were examined in striatal tissue at 30 and 100 min after apomorphine injection. At 30 min, wild-type and transgenic mice showed a similar induction of phosphorylated ERK1/2, Dusp1, and Dusp6 mRNA (two MAPK phosphatases). At the same time point, Fos mRNA was induced more strongly in mutant mice than in wild-type controls. At 100 min after apomorphine treatment, the induction of both Fos, Dusp1, and Dusp6 mRNA was significantly larger in mutant mice than wild-type controls. At this time point, apomorphine caused a reduction in phospho-ERK1/2 levels specifically in the transgenic mice. Our results document for the first time a disturbance of ERK1/2 signaling regulation associated with apomorphine-induced involuntary movements in a genetic mouse model of synucleinopathy. This mouse model will be useful to identify novel therapeutic targets that can counteract abnormal dopamine-dependent striatal plasticity during both prodromal and manifest stages of PD.

Topics: alpha-Synuclein; Animals; Apomorphine; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Dyskinesias; Extracellular Signal-Regulated MAP Kinases; Humans; Locomotion; MAP Kinase Signaling System; Mice; Mice, Transgenic; Mutation, Missense; Nerve Tissue Proteins; Parkinsonian Disorders; Phosphorylation; Point Mutation; Post-Synaptic Density; Prions; Promoter Regions, Genetic; Protein Processing, Post-Translational; Stereotyped Behavior; Substantia Nigra; Transgenes

Parkinson's disease (PD) is characterized by selective degeneration of dopaminergic neurons. Although the etiology of PD remains incompletely understood, oxidative stress has been implicated as an important contributor in the development of PD. Oxidative stress can lead to oxidation and functional perturbation of proteins critical to neuronal survival. Glutaredoxin 1 (Grx1) is an evolutionally conserved antioxidant enzyme that repairs protein oxidation by reversing the oxidative modification of cysteine known as S-glutathionylation. We aimed to explore the regulatory role of Grx1 in PD. We first examined the levels of Grx1 in postmortem midbrain samples from PD patients, and observed that Grx1 content is decreased in PD, specifically within the dopaminergic neurons. We subsequently investigated the potential role of Grx1 deficiency in PD pathogenesis by examining the consequences of loss of the Caenorhabditis elegans Grx1 homolog in well-established worm models of familial PD caused by overexpression of pathogenic human LRRK2 mutants G2019S or R1441C. We found that loss of the Grx1 homolog led to significant exacerbation of the neurodegenerative phenotype in C. elegans overexpressing the human LRRK2 mutants. Re-expression in the dopaminergic neurons of the active, but not a catalytically inactive form of the Grx1 homolog rescued the exacerbated phenotype. Loss of the Grx1 homolog also exacerbated the neurodegenerative phenotype in other C. elegans models, including overexpression of human α-synuclein and overexpression of tyrosine hydroxylase (a model of sporadic PD). Therefore, our results reveal a novel neuroprotective role of glutaredoxin against dopaminergic neurodegeneration in models of familial and sporadic PD.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Cell Survival; Cysteine; Disease Models, Animal; Dopaminergic Neurons; Evolution, Molecular; Gene Expression Regulation; Glutaredoxins; Helminth Proteins; Homeostasis; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mesencephalon; Oxidative Stress; Parkinson Disease; Phenotype; Protein Serine-Threonine Kinases; RNA, Messenger; Tyrosine 3-Monooxygenase

Aggregation of α-synuclein (α-syn) and α-syn cytotoxicity are hallmarks of sporadic and familial Parkinson disease (PD), with accumulating evidence that prefibrillar oligomers and protofibrils are the pathogenic species in PD and related synucleinopathies. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a key regulator of mitochondrial biogenesis and cellular energy metabolism, has recently been associated with the pathophysiology of PD. Despite extensive effort on studying the function of PGC-1α in mitochondria, no studies have addressed whether PGC-1α directly influences oligomerization of α-syn or whether α-syn oligomers impact PGC-1α expression.. We tested whether pharmacological or genetic activation of PGC-1α or PGC-11α knockdown could modulate the oligomerization of α-syn in vitro by using an α-syn -fragment complementation assay.. In this study, we found that both PGC-1α reference gene (RG-PGC-1α) and the central nervous system (CNS)-specific PGC-1α (CNS-PGC-1α) are downregulated in human PD brain, in A30P α-syn transgenic animals, and in a cell culture model for α-syn oligomerization. Importantly, downregulation of both RG-PGC-1α and CNS-PGC-1α in cell culture or neurons from RG-PGC-1α-deficient mice leads to a strong induction of α-syn oligomerization and toxicity. In contrast, pharmacological activation or genetic overexpression of RG-PGC-1α reduced α-syn oligomerization and rescued α-syn-mediated toxicity.. Based on our results, we propose that PGC-1α downregulation and α-syn oligomerization form a vicious circle, thereby influencing and/or potentiating each other. Our data indicate that restoration of PGC-1α is a promising approach for development of effective drugs for the treatment of PD and related synucleinopathies.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Embryo, Mammalian; Enzyme Inhibitors; Female; Gene Expression Regulation; Glioma; Humans; Macrolides; Male; Mice; Mice, Transgenic; Middle Aged; Neurons; Parkinson Disease; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; PPAR gamma; Resveratrol; RNA Polymerase II; Stilbenes; Substantia Nigra; TATA-Box Binding Protein; Transcription Factors

Accumulation and aggregation of alpha-synuclein in cortical and hippocampal areas is a pathological sign for dementia with Lewy bodies (DLB) and Parkinson's disease with dementia. However the mechanisms of alpha-synuclein triggered cellular dysfunction leading to the development of memory impairment is not clear. We have created a mouse model of DLB, where aggregation-prone human truncated (120 amino acid) alpha-synuclein is expressed in forebrain areas under the calcium/calmodulin-dependent protein kinase II alpha (CamKII-alpha) promoter. We have observed the presence of the transgenic protein in target forebrain areas, with small granular cytoplasmic accumulation of aggregated alpha-synuclein. This was associated with a progressive deficit in cortical-hippocampal memory tests including the Barnes maze and novel object recognition. This data suggests that low levels of aggregation prone alpha-synuclein are sufficient to induce memory deficits in mice and that forebrain regions associated with cognitive function may have an increased sensitivity to the truncated toxic form of alpha-synuclein.

Topics: Age Factors; alpha-Synuclein; Animals; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Disease Models, Animal; Exploratory Behavior; Gene Expression Regulation; Humans; Lewy Body Disease; Male; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Peptide Fragments; Prosencephalon; RNA, Messenger

Protein misfolding and aggregation is a major hallmark of neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Until recently, the consensus was that each aggregation-prone protein was characteristic of each disorder [α-synuclein (α-syn)/PD, mutant huntingtin (Htt)/HD, Tau and amyloid beta peptide/AD]. However, growing evidence indicates that aggregation-prone proteins can actually co-aggregate and modify each other's behavior and toxicity, suggesting that this process may also contribute to the overlap in clinical symptoms across different diseases. Here, we show that α-syn and mutant Htt co-aggregate in vivo when co-expressed in Drosophila and produce a synergistic age-dependent increase in neurotoxicity associated to a decline in motor function and life span. Altogether, our results suggest that the co-existence of α-syn and Htt in the same neuronal cells worsens aggregation-related neuropathologies and accelerates disease progression.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila; Female; Humans; Huntingtin Protein; Male; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Aggregates

Mutations in the ATP13A2 (PARK9) gene cause early-onset, autosomal recessive Parkinson's disease (PD) and Kufor-Rakeb syndrome. ATP13A2 mRNA is spliced into three distinct isoforms encoding a P5-type ATPase involved in regulating heavy metal transport across vesicular membranes. Here, we demonstrate that three ATP13A2 mRNA isoforms are expressed in the normal human brain and are modestly increased in the cingulate cortex of PD cases. ATP13A2 can mediate protection toward a number of stressors in mammalian cells and can protect against α-synuclein-induced toxicity in cellular and invertebrate models of PD. Using a primary cortical neuronal model combined with lentiviral-mediated gene transfer, we demonstrate that human ATP13A2 isoforms 1 and 2 display selective neuroprotective effects toward toxicity induced by manganese and hydrogen peroxide exposure through an ATPase-independent mechanism. The familial PD mutations, F182L and G504R, abolish the neuroprotective effects of ATP13A2 consistent with a loss-of-function mechanism. We further demonstrate that the AAV-mediated overexpression of human ATP13A2 is not sufficient to attenuate dopaminergic neurodegeneration, neuropathology, and striatal dopamine and motoric deficits induced by human α-synuclein expression in a rat model of PD. Intriguingly, the delivery of an ATPase-deficient form of ATP13A2 (D513N) to the substantia nigra is sufficient to induce dopaminergic neuronal degeneration and motor deficits in rats, potentially suggesting a dominant-negative mechanism of action. Collectively, our data demonstrate a distinct lack of ATP13A2-mediated protection against α-synuclein-induced neurotoxicity in the rat nigrostriatal dopaminergic pathway, and limited neuroprotective capacity overall, and raise doubts about the potential of ATP13A2 as a therapeutic target for PD.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Female; Humans; Hydrogen Peroxide; Male; Manganese; Middle Aged; Neuroprotective Agents; Parkinsonian Disorders; Pregnancy; Proton-Translocating ATPases; Rats; Rats, Sprague-Dawley; Tissue Banks

Dopaminergic degeneration is a major finding in brains of patients with Parkinson's disease (PD), together with Lewy bodies, intraneuronal inclusions mainly composed of the fibrillogenic protein α-synuclein (α-syn). The familial-PD-related protein DJ-1 was reported to reduce dopaminergic degeneration triggered by α-syn or by the dopaminergic-selective neurotoxin 6-hydroxydopamine (6-OHDA).. The aim was to further investigate the role of DJ-1 in dopaminergic degeneration and to see whether a cell-permeable recombinant form of DJ-1 (TAT-DJ-1) could restore dopamine depletion in vivo, thus representing an innovative therapeutic approach.. We developed in vitro (PC12/TetOn cells and mouse primary mesencephalic neurons) and in vivo models [including DJ-1 knockout (-/-) mice] to investigate DJ-1 in dopaminergic degeneration.. We found that in PC12/TetOn cells overexpressing α-syn with the familial-PD linked mutation A30P, DJ-1 silencing increased α-syn (A30P) toxicity. Primary mesencephalic neurons from DJ-1 (-/-) mice were more vulnerable to a cell-permeable form of α-syn (TAT-α-syn) and to 6-OHDA. Intrastriatally administered TAT-DJ-1 reduced 6-OHDA toxicity in vivo in C57BL/6 mice. Finally, when we injected TAT-α-syn (A30P) in the striatum of DJ-1 (-/-) animals, dopamine was depleted more than in the control strain.. DJ-1 appears to have a protective role against dopaminergic degeneration triggered by α-syn or 6-OHDA, reinforcing the possible therapeutic importance of this protein in PD.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Nerve Degeneration; Oncogene Proteins; Oxidopamine; Parkinson Disease; Peroxiredoxins; Protein Deglycase DJ-1; Up-Regulation

Parkinson's disease (PD) is an age-dependent neurodegenerative disease that can be caused by genetic mutations in α-synuclein (α-syn) or duplication of wild-type α-syn; PD is characterized by the deposition of α-syn aggregates, indicating a gain of toxicity from accumulation of α-syn. Although the major neuropathologic feature of PD is the degeneration of dopaminergic (DA) neurons in the substantia nigra, non-motor symptoms including anxiety, cognitive defect and sleep disorder precede the onset of motor impairment, and many clinical symptoms of PD are not caused by degeneration of DA neurons. Non-human primate models of PD are important for revealing the early pathology in PD and identifying effective treatments. We established transgenic PD rhesus monkeys that express mutant α-syn (A53T). Six transgenic A53T monkeys were produced via lentiviral vector expressing A53T in fertilized monkey eggs and subsequent embryo transfer to surrogates. Transgenic A53T is expressed in the monkey brain and causes age-dependent non-motor symptoms, including cognitive defects and anxiety phenotype, without detectable sleeping disorders. The transgenic α-syn monkeys demonstrate the specific early symptoms caused by mutant α-syn and provide insight into treatment of early PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Disease Models, Animal; Dopaminergic Neurons; Female; Humans; Macaca mulatta; Male; Parkinson Disease

Patients with Parkinson's disease (PD) may exhibit deficits in "Theory of Mind", the ability to read others' mental states and react appropriately, a prerequisite for successful social interaction. Alpha-synuclein overexpression is widely distributed in the brain of patients with sporadic PD, suggesting that it may contribute to the non-motor deficits observed in PD patients. Mice over-expressing human wild-type alpha-synuclein under the Thy1 promoter (Thy1-aSyn mice) have synaptic deficits in the frontostriatal pathway, low cortical acetylcholine, and high level of expression of mGluR5 receptors, which have all been implicated in social recognition deficits.. To determine whether Thy1-aSyn mice present alterations in their response to social stimuli.. We have submitted Thy1-aSyn mice to tests adapted from autism models.. At 7-8 month of age Thy1-aSyn mice explored their conspecifics significantly less than did wild-type littermates, without differences in exploration of inanimate objects, and pairs of Thy1-aSyn mice were involved in reciprocal interactions for a shorter duration than wild-type mice at this age. These deficits persisted when the test animal was enclosed in a beaker and were not present at 3-4 months of age despite the presence of olfactory deficits at that age, indicating that they were not solely caused by impairment in olfaction.. Thy1-aSyn mice present progressive deficits in social recognition, supporting an association between alpha-synuclein overexpression and Theory of Mind deficits in PD and providing a useful model for identifying mechanisms and testing novel treatments for these deficits which impact patients and caretakers quality of life.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Cognition; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; Promoter Regions, Genetic; Social Behavior; Theory of Mind

Testing of new therapeutic strategies for Parkinson's disease (PD) is currently hampered by the lack of relevant and reproducible animal models. Here, we developed a robust rat model for PD by injection of adeno-associated viral vectors (rAAV2/7) encoding α-synuclein into the substantia nigra, resulting in reproducible nigrostriatal pathology and behavioral deficits in a 4-week time period. Progressive dopaminergic dysfunction was corroborated by histopathologic and biochemical analysis, motor behavior testing and in vivo microdialysis. L-DOPA treatment was found to reverse the behavioral phenotype. Non-invasive positron emission tomography imaging and magnetic resonance spectroscopy allowed longitudinal monitoring of neurodegeneration. In addition, insoluble α-synuclein aggregates were formed in this model. This α-synuclein rat model shows improved face and predictive validity, and therefore offers the possibility to reliably test novel therapeutics. Furthermore, it will be of great value for further research into the molecular pathogenesis of PD and the importance of α-synuclein aggregation in the disease process.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Dependovirus; Disease Models, Animal; Disease Progression; Dopamine; Gene Expression; Genetic Vectors; Longitudinal Studies; Microdialysis; Parkinson Disease; Positron-Emission Tomography; Protein Aggregates; Substantia Nigra; Time Factors

Sirtuin deacetylases regulate diverse cellular pathways and influence disease processes. Our previous studies identified the brain-enriched sirtuin-2 (SIRT2) deacetylase as a potential drug target to counteract neurodegeneration. In the present study, we characterize SIRT2 inhibition activity of the brain-permeable compound AK7 and examine the efficacy of this small molecule in models of Parkinson's disease, amyotrophic lateral sclerosis and cerebral ischemia. Our results demonstrate that AK7 is neuroprotective in models of Parkinson's disease; it ameliorates alpha-synuclein toxicity in vitro and prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine depletion and dopaminergic neuron loss in vivo. The compound does not show beneficial effects in mouse models of amyotrophic lateral sclerosis and cerebral ischemia. These findings underscore the specificity of protective effects observed here in models of Parkinson's disease, and previously in Huntington's disease, and support the development of SIRT2 inhibitors as potential therapeutics for the two neurodegenerative diseases.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Amyotrophic Lateral Sclerosis; Animals; Benzamides; Brain Ischemia; Cell Line; Disease Models, Animal; Humans; Male; Mice; Neuroprotective Agents; Parkinson Disease; Sirtuin 2; Small Molecule Libraries; Sulfonamides

In vitro evidence suggests that the inefficient removal of damaged mitochondria by macroautophagy contributes to Parkinson's disease (PD). Using a tissue-specific gene amplification strategy, we generated a transgenic mouse line with human α-synuclein A53T overexpression specifically in dopamine (DA) neurons. Transgenic mice showed profound early-onset mitochondria abnormalities, characterized by macroautophagy marker-positive cytoplasmic inclusions containing mainly mitochondrial remnants, which preceded the degeneration of DA neurons. Genetic deletion of either parkin or PINK1 in these transgenic mice significantly worsened mitochondrial pathologies, including drastically enlarged inclusions and loss of total mitochondria contents. These data suggest that mitochondria are the main targets of α-synuclein and their defective autophagic clearance plays a significant role during pathogenesis. Moreover, endogenous PINK1 or parkin is indispensable for the proper autophagic removal of damaged mitochondria. Our data for the first time establish an essential link between mitochondria macroautophagy impairments and DA neuron degeneration in an in vivo model based on known PD genetics. The model, its well-defined pathologies, and the demonstration of a main pathogenesis pathway in the present study have set the stage and direction of emphasis for future studies.

Topics: alpha-Synuclein; Animals; Autophagy; Cell Count; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Humans; Mice; Mice, Transgenic; Mitochondria; Nerve Degeneration; Parkinson Disease; Protein Kinases; Ubiquitin-Protein Ligases

Alpha-synuclein (α-synuclein) is considered a key player in Parkinson's disease (PD), but the exact relationship between α-synuclein aggregation and dopaminergic neurodegeneration remains unresolved. There is increasing evidence that neuroinflammatory processes are closely linked to dopaminergic cell death, but whether the inflammatory process is causally involved in PD or rather reflects secondary consequences of nigrostriatal pathway injury is still under debate. We evaluated the therapeutic effect of the immunophilin ligand FK506 in a rAAV2/7 α-synuclein overexpression rat model. Treatment with FK506 significantly increased the survival of dopaminergic neurons in a dose-dependent manner. No reduction in α-synuclein aggregation was apparent in this time window, but FK506 significantly lowered the infiltration of both T helper and cytotoxic T cells and the number and subtype of microglia and macrophages. These data suggest that the anti-inflammatory properties of FK506 decrease neurodegeneration in this α-synuclein-based PD model, pointing to a causal role of neuroinflammation in the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents; Cell Death; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Dose-Response Relationship, Drug; Female; Gene Expression; Immunosuppressive Agents; Inflammation; Male; Microglia; Parkinson Disease; Protein Aggregates; Rats, Wistar; Tacrolimus

In order to develop a cell-based vaccine against the Parkinson disease (PD) associated protein α-synuclein (α-Syn) 3 peptides were synthesized based upon predicted B cell epitopes within the full length α-Syn protein sequence. These peptide fragments as well as the full length recombinant human α-Syn (rh- α-Syn) protein were used to sensitize mouse bone marrow-derived dendritic cells (DC) ex vivo, followed by intravenous delivery of these sensitized DCs into transgenic (Tg) mice expressing the human A53T variant of α-Syn. ELISA analysis and testing of behavioral locomotor function by rotometry were performed on all mice after the 5th vaccination as well as just prior to euthanasia. The results indicated that vaccination with peptide sensitized DCs (PSDC) as well as DCs sensitized by rh-α-Syn induced specific anti-α-Syn antibodies in all immunized mice. In terms of rotometry performance, a measure of locomotor activity correlated to brain dopamine levels, mice vaccinated with PSDC or rh- α-Syn sensitized DCs performed significantly better than non-vaccinated Tg control mice during the final assessment (i.e. at 17 months of age) before euthanasia. As well, measurement of levels of brain IL-1α, a cytokine hypothesized to be associated with neuroinflammation, demonstrated that this proinflammatory molecule was significantly reduced in the PSDC and rh- α-Syn sensitized DC vaccinated mice compared to the non-vaccinated Tg control group. Overall, α-Syn antigen-sensitized DC vaccination was effective in generating specific anti- α-Syn antibodies and improved locomotor function without eliciting an apparent general inflammatory response, indicating that this strategy may be a safe and effective treatment for PD.

Topics: alpha-Synuclein; Animals; Cell- and Tissue-Based Therapy; Dendritic Cells; Disease Models, Animal; Female; Humans; Mice; Mice, Transgenic; Motor Activity; Parkinson Disease; Vaccines

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause late-onset, autosomal dominant Parkinson's disease (PD). LRRK2 contains functional GTPase and kinase domains. The most common G2019S mutation enhances the kinase activity of LRRK2 in vitro whereas G2019S LRRK2 expression in cultured neurons induces toxicity in a kinase-dependent manner. These observations suggest a potential role for kinase activity in LRRK2-associated PD. We have recently developed a novel rodent model of PD with progressive neurodegeneration induced by the adenoviral-mediated expression of G2019S LRRK2. In the present study, we further characterize this LRRK2 model and determine the contribution of kinase activity to LRRK2-mediated neurodegeneration. Recombinant human adenoviral vectors were employed to deliver human wild-type, G2019S or kinase-inactive G2019S/D1994N LRRK2 to the rat striatum. LRRK2-dependent pathology was assessed in the striatum, a region where LRRK2 protein is normally enriched in the mammalian brain. Human LRRK2 variants are robustly expressed throughout the rat striatum. Expression of G2019S LRRK2 selectively induces the accumulation of neuronal ubiquitin-positive inclusions accompanied by neurite degeneration and the altered distribution of axonal phosphorylated neurofilaments. Importantly, the introduction of a kinase-inactive mutation (G2019S/D1994N) completely ameliorates the pathological effects of G2019S LRRK2 in the striatum supporting a kinase activity-dependent mechanism for this PD-associated mutation. Collectively, our study further elucidates the pathological effects of the G2019S mutation in the mammalian brain and supports the development of kinase inhibitors as a potential therapeutic approach for treating LRRK2-associated PD. This adenoviral rodent model provides an important tool for elucidating the molecular basis of LRRK2-mediated neurodegeneration.

Topics: Adenoviridae; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Female; Forelimb; Gene Expression Regulation; Glycine; HEK293 Cells; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Parkinson Disease; Phosphopyruvate Hydratase; Protein Serine-Threonine Kinases; Rats; Rats, Wistar; Serine; Time Factors; Transduction, Genetic; Tubulin

Aggregated alpha-synuclein inclusions are found where cell death occurs in several diseases, including Parkinson's disease, dementia with Lewy bodies, and multiple-system atrophy. However, the relationship between inclusion formation and an individual cell's fate has been difficult to study with conventional techniques. We developed a system that allows for in vivo imaging of the same neurons over months. We show that intracerebral injection of preformed fibrils of recombinant alpha-synuclein can seed aggregation of transgenically expressed and endogenous alpha-synuclein in neurons. Somatic inclusions undergo a stage-like maturation, with progressive compaction coinciding with decreased soluble somatic and nuclear alpha-synuclein. Mature inclusions bear the post-translational hallmarks of human Lewy pathology. Long-term imaging of inclusion-bearing neurons and neighboring neurons without inclusions demonstrates selective degeneration of inclusion-bearing cells. Our results indicate that inclusion formation is tightly correlated with cellular toxicity and that seeding may be a pathologically relevant mechanism of progressive neurodegeneration in many synucleinopathies.

Topics: Aged; alpha-Synuclein; Animals; Disease Models, Animal; Female; Fluorescence Recovery After Photobleaching; Frontal Lobe; Humans; Immunohistochemistry; Lewy Bodies; Male; Mice; Neurons; Parkinson Disease

We used double immunocytochemistry for α-synuclein and markers of sympathoexcitatory neurons, oligodendrocytes, iron metabolism, and autophagy to study putative neuropathological interactions in multiple system atrophy. We focused in the rostral ventrolateral medulla as a prototype vulnerable region. We found that loss of C1 neurons and oligodendrocytes related to glial cytoplasmic inclusion accumulation, downregulation of iron transport, and upregulation of autophagy and ferritin expression in these area.

Topics: Aged; alpha-Synuclein; Animals; Apoptosis Regulatory Proteins; Beclin-1; Brain Stem; Case-Control Studies; Cation Transport Proteins; Disease Models, Animal; Humans; Male; Membrane Proteins; Mice; Middle Aged; Multiple System Atrophy; Neuroglia; Oligodendroglia

Oxidative stress is believed to be a major factor for the onset of Parkinson's disease (PD). In this study, we have investigated oxidative status in transgenic Drosophila model of PD. Our results revealed elevated levels of reactive oxygen species (ROS) and lipid peroxidation (LPO) in A30P and A53T α-synuclein PD model flies compared to control. We have demonstrated for the first time the ameliorating potential of natural antioxidants characterized from the roots of Dh in A30P and A53T α-synuclein PD model flies. Feeding of transgenic flies with aqueous Dh root extract for 21 days significantly improved their climbing ability and circadian rhythm of locomotor activity which was associated with reduction in levels of ROS and LPO and enhancement in the activities of catalase (CAT) and superoxide dismutase (SOD). Dh protected against paraquat (PQ) sensitivity in α-synuclein transgenic flies and delayed the onset of PD-like symptoms which appears to be mediated by suppression of oxidative stress.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antioxidants; Circadian Rhythm; Disease Models, Animal; Drosophila; Lipid Peroxidation; Motor Activity; Oxidative Stress; Parkinson Disease; Plant Extracts; Plant Roots; Reactive Oxygen Species

Homozygous mutations in the glucocerebrosidase (GBA) gene result in Gaucher disease (GD), the most common lysosomal storage disease. Recent genetic studies have revealed that GBA mutations confer a strong risk for sporadic Parkinson's disease (PD). To investigate how GBA mutations cause PD, we generated GBA nonsense mutant (GBA-/-) medaka that are completely deficient in glucocerebrosidase (GCase) activity. In contrast to the perinatal death in humans and mice lacking GCase activity, GBA-/- medaka survived for months, enabling analysis of the pathological progression. GBA-/- medaka displayed the pathological phenotypes resembling human neuronopathic GD including infiltration of Gaucher cell-like cells into the brains, progressive neuronal loss, and microgliosis. Detailed pathological findings represented lysosomal abnormalities in neurons and alpha-synuclein (α-syn) accumulation in axonal swellings containing autophagosomes. Unexpectedly, disruption of α-syn did not improve the life span, formation of axonal swellings, neuronal loss, or neuroinflammation in GBA-/- medaka. Taken together, the present study revealed GBA-/- medaka as a novel neuronopathic GD model, the pahological mechanisms of α-syn accumulation caused by GCase deficiency, and the minimal contribution of α-syn to the pathogenesis of neuronopathic GD.

Topics: alpha-Synuclein; Animals; Axons; Disease Models, Animal; Gaucher Disease; Glucosylceramidase; Oryzias; Phagosomes

Interneuronal propagation of α-synuclein has been demonstrated in a variety of experimental models and may be involved in disease progression during the course of human synucleinopathies. The aim of this study was to assess the role that neuronal injury or, vice versa, cell integrity could have in facilitating interneuronal α-synuclein transfer and consequent protein spreading in an in vivo animal model.. Viral vectors carrying the DNA for human α-synuclein were injected into the rat vagus nerve to trigger protein overexpression in the medulla oblongata and consequent spreading of human α-synuclein toward pons, midbrain and forebrain. Two vector preparations sharing the same viral construct were manufactured using identical procedures with the exception of methods for their purification. They were also injected at concentrations that induced comparable levels of α-synuclein transduction/overexpression in the medulla oblongata. α-Synuclein load was associated with damage (at 6 weeks post injection) and death (at 12 weeks) of medullary neurons after treatment with only one of the two vector preparations. Of note, neuronal injury and degeneration was accompanied by a substantial reduction of caudo-rostral propagation of human α-synuclein.. Interneuronal α-synuclein transfer, which underlies protein spreading from the medulla oblongata to more rostral brain regions in this rat model, is not a mere consequence of passive release from damaged or dead neurons. Neuronal injury and degeneration did not exacerbate α-synuclein propagation. In fact, data suggest that cell-to-cell passage of α-synuclein may be particularly efficient between intact, relatively healthy neurons.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Female; Gene Transfer Techniques; Humans; Medulla Oblongata; Nerve Degeneration; Neural Pathways; Neurons; Parkinson Disease; Rats; Rats, Sprague-Dawley

Accumulating evidence from genetic and biochemical studies implicates dysfunction of the autophagic-lysosomal pathway as a key feature in the pathogenesis of Parkinson's disease (PD). Most studies have focused on accumulation of neurotoxic α-synuclein secondary to defects in autophagy as the cause of neurodegeneration, but abnormalities of the autophagic-lysosomal system likely mediate toxicity through multiple mechanisms. To further explore how endolysosomal dysfunction causes PD-related neurodegeneration, we generated a murine model of Kufor-Rakeb syndrome (KRS), characterized by early-onset Parkinsonism with additional neurological features. KRS is caused by recessive loss-of-function mutations in the ATP13A2 gene encoding the endolysosomal ATPase ATP13A2. We show that loss of ATP13A2 causes a specific protein trafficking defect, and that Atp13a2 null mice develop age-related motor dysfunction that is preceded by neuropathological changes, including gliosis, accumulation of ubiquitinated protein aggregates, lipofuscinosis, and endolysosomal abnormalities. Contrary to predictions from in vitro data, in vivo mouse genetic studies demonstrate that these phenotypes are α-synuclein independent. Our findings indicate that endolysosomal dysfunction and abnormalities of α-synuclein homeostasis are not synonymous, even in the context of an endolysosomal genetic defect linked to Parkinsonism, and highlight the presence of α-synuclein-independent neurotoxicity consequent to endolysosomal dysfunction.

Topics: Adenosine Triphosphatases; alpha-Synuclein; Animals; Brain; Cytosol; Disease Models, Animal; Dopaminergic Neurons; Endosomes; Exploratory Behavior; Hindlimb Suspension; Hydrogen-Ion Concentration; Lipids; Lysosomes; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Motor Activity; Nerve Tissue Proteins; Parkinsonian Disorders; Postural Balance; Proton-Translocating ATPases

Age-related structural changes and gradual loss of key enzymes significantly affect the ability of the endoplasmic reticulum (ER) to facilitate proper protein folding and maintain homeostasis. In this work, we present several lines of evidence supporting the hypothesis that the age-related decline in expression of the ER chaperone glucose-regulated protein 78 (GRP78) could be related to the development of Parkinson's disease. We first determined that old (24 months) rats exhibit significantly lower levels of GRP78 protein in the nigrostriatal system as compared with young (2 months) animals. Then using recombinant adeno-associate virus-mediated gene transfer, we found that GRP78 downregulation by specific small interfering RNAs (siRNAs) aggravates alpha-synuclein (α-syn) neurotoxicity in nigral dopamine (DA) neurons. Moreover, the degree of chaperone decline corresponds with the severity of neurodegeneration. Additionally, comparative analysis of nigral tissues obtained from old and young rats revealed that aging affects the capacity of nigral DA cells to upregulate endogenous GRP78 protein in response to human α-syn neurotoxicity. Finally, we demonstrated that a sustained increase of GRP78 protein over the course of 9 months protected aging nigral DA neurons in the α-syn-induced rat model of Parkinson's-like neurodegeneration. Our data indicate that the ER chaperone GRP78 may have therapeutic potential for preventing and/or slowing age-related neurodegeneration.

Topics: Aging; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Down-Regulation; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Female; Gene Knockdown Techniques; Heat-Shock Proteins; Homeostasis; Humans; Male; Molecular Chaperones; Parkinson Disease; Protein Folding; Rats, Inbred F344; RNA, Small Interfering; Substantia Nigra

Parkinson's disease (PD) is the second most common neurodegenerative disorder in the elderly people, currently with no cure. Its mechanisms are not well understood, thus studies targeting cause-directed therapy or prevention are needed. This study uses the transgenic Caenorhabditis elegans PD model. We demonstrated that dietary supplementation of the worms with an extract from the cultivated red seaweed Chondrus crispus decreased the accumulation of α-synulein and protected the worms from the neuronal toxin-, 6-OHDA, induced dopaminergic neurodegeneration. These effects were associated with a corrected slowness of movement. We also showed that the enhancement of oxidative stress tolerance and an up-regulation of the stress response genes, sod-3 and skn-1, may have served as the molecular mechanism for the C. crispus-extract-mediated protection against PD pathology. Altogether, apart from its potential as a functional food, the tested red seaweed, C. crispus, might find promising pharmaceutical applications for the development of potential novel anti-neurodegenerative drugs for humans.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Aquaculture; Bacterial Proteins; Behavior, Animal; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Chondrus; Dietary Supplements; Disease Models, Animal; Dopaminergic Neurons; Humans; Luminescent Proteins; Microscopy, Fluorescence; Movement; Neuroprotective Agents; Neurotoxins; Oxidative Stress; Parkinson Disease; Plant Extracts; Recombinant Fusion Proteins; Seaweed

Multiple system atrophy (MSA) is a neurodegenerative disease characterized by parkinsonism, ataxia and dysautonomia. Histopathologically, the hallmark of MSA is the abnormal accumulation of alpha-synuclein (α-syn) within oligodendroglial cells, leading to neuroinflammation, demyelination and neuronal death. Currently, there is no disease-modifying treatment for MSA. In this sense, we have previously shown that next-generation active vaccination technology with short peptides, AFFITOPEs®, was effective in two transgenic models of synucleinopathies at reducing behavioral deficits, α-syn accumulation and inflammation.. In this manuscript, we used the most effective AFFITOPE® (AFF 1) for immunizing MBP-α-syn transgenic mice, a model of MSA that expresses α-syn in oligodendrocytes. Vaccination with AFF 1 resulted in the production of specific anti-α-syn antibodies that crossed into the central nervous system and recognized α-syn aggregates within glial cells. Active vaccination with AFF 1 resulted in decreased accumulation of α-syn, reduced demyelination in neocortex, striatum and corpus callosum, and reduced neurodegeneration. Clearance of α-syn involved activation of microglia and reduced spreading of α-syn to astroglial cells.. This study further validates the efficacy of vaccination with AFFITOPEs® for ameliorating the neurodegenerative pathology in synucleinopathies.

Topics: alpha-Synuclein; Animals; Astrocytes; Demyelinating Diseases; Disease Models, Animal; Mice, Transgenic; Microglia; Multiple System Atrophy; Neurons; Oligodendroglia; Parkinsonian Disorders; Vaccination

α-Synuclein (α-Syn) is hypothesized to have a critical role in sporadic and genetic cases of Parkinson's disease (PD) in which Lewy bodies, as the hallmark of PD, are formed from abnormal aggregates of α-Syn. To determine the role of α-Syn in the motor and cognitive dysfunction observed in PD, a Drosophila melanogaster model was established to investigate the electrophysiological and ethological changes caused by overexpression of α-Syn. The present data indicated that α-Syn overexpression reduced the synaptic transmission of cholinergic neurons by modulating the calcium channel currents in the projection neurons in the antennal lobe region of the Drosophila brain, as well as the learning and memory ability of the flies. However, the locomotor ability of the Drosophila remained unaffected. The present findings suggested that α-Syn may be associated with senile dementia in patients with PD.

Topics: alpha-Synuclein; Animals; Brain; Calcium; Calcium Channels; Cognition; Disease Models, Animal; Drosophila melanogaster; Humans; Learning; Memory; Neurons; Parkinson Disease; Synaptic Transmission; Up-Regulation

Parkinson's disease (PD) is one of the most common causes of dementia and motor deficits in the elderly. PD is characterized by the abnormal accumulation of the synaptic protein alpha-synuclein (α-syn) and degeneration of dopaminergic neurons in substantia nigra, which leads to neurodegeneration and neuroinflammation. Currently, there are no disease modifying alternatives for PD; however, targeting neuroinflammation might be a viable option for reducing motor deficits and neurodegeneration. Lenalidomide is a thalidomide derivative designed for reduced toxicity and increased immunomodulatory properties. Lenalidomide has shown protective effects in an animal model of amyotrophic lateral sclerosis, and its mechanism of action involves modulation of cytokine production and inhibition of NF-κB signaling.. In order to assess the effect of lenalidomide in an animal model of PD, mThy1-α-syn transgenic mice were treated with lenalidomide or the parent molecule thalidomide at 100 mg/kg for 4 weeks.. Lenalidomide reduced motor behavioral deficits and ameliorated dopaminergic fiber loss in the striatum. This protective action was accompanied by a reduction in microgliosis both in striatum and hippocampus. Central expression of pro-inflammatory cytokines was diminished in lenalidomide-treated transgenic animals, together with reduction in NF-κB activation.. These results support the therapeutic potential of lenalidomide for reducing maladaptive neuroinflammation in PD and related neuropathologies.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Cell Line, Transformed; Cytokines; Disease Models, Animal; Dopamine; Glial Fibrillary Acidic Protein; Immunologic Factors; Lenalidomide; Mental Disorders; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Parkinson Disease; RNA, Messenger; Signal Transduction; Thalidomide

In addition to established methods like Western blot, new methods are needed to quickly and easily quantify disease-associated α-synuclein (αS(D)) in experimental models of synucleopathies. A transgenic mouse line (M83) over-expressing the human A53T αS and spontaneously developing a dramatic clinical phenotype between eight and 22 months of age, characterized by symptoms including weight loss, prostration, and severe motor impairment, was used in this study. For molecular analyses of αS(D) (disease-associated αS) in these mice, an ELISA was designed to specifically quantify αS(D) in sick mice. Analysis of the central nervous system in this mouse model showed the presence of αS(D) mainly in the caudal brain regions and the spinal cord. There were no differences in αS(D) distribution between different experimental conditions leading to clinical disease, i.e., in uninoculated and normally aging transgenic mice and in mice inoculated with brain extracts from sick mice. The specific detection of αS(D) immunoreactivity using an antibody against Ser129 phosphorylated αS by ELISA essentially correlated with that obtained by Western blot and immunohistochemistry. Unexpectedly, similar results were observed with several other antibodies against the C-terminal part of αS. The propagation of αS(D), suggesting the involvement of a "prion-like" mechanism, can thus be easily monitored and quantified in this mouse model using an ELISA approach.

Topics: alpha-Synuclein; Animals; Blotting, Western; Brain; Brain Chemistry; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Humans; Immunohistochemistry; Mice; Mice, Transgenic; Phosphorylation; Prions; Spinal Cord

Multiple convergent lines of evidence implicate both α-synuclein (encoded by SCNA) and mitochondrial dysfunction in the pathogenesis of sporadic Parkinson's disease (PD). Occupational exposure to the mitochondrial complex I inhibitor rotenone increases PD risk; rotenone-exposed rats show systemic mitochondrial defects but develop specific neuropathology, including α-synuclein aggregation and degeneration of substantia nigra dopaminergic neurons. Here, we inhibited expression of endogenous α-synuclein in the adult rat substantia nigra by adeno-associated virus-mediated delivery of a short hairpin RNA (shRNA) targeting the endogenous rat Snca transcript. Knockdown of α-synuclein by ~35% did not affect motor function or cause degeneration of nigral dopaminergic neurons in control rats. However, in rotenone-exposed rats, progressive motor deficits were substantially attenuated contralateral to α-synuclein knockdown. Correspondingly, rotenone-induced degeneration of nigral dopaminergic neurons, their dendrites, and their striatal terminals was decreased ipsilateral to α-synuclein knockdown. These data show that α-synuclein knockdown is neuroprotective in the rotenone model of PD and indicate that endogenous α-synuclein contributes to the specific vulnerability of dopaminergic neurons to systemic mitochondrial inhibition. Our findings are consistent with a model in which genetic variants influencing α-synuclein expression modulate cellular susceptibility to environmental exposures in PD patients. shRNA targeting the SNCA transcript should be further evaluated as a possible neuroprotective therapy in PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Gene Knockdown Techniques; Male; Nerve Degeneration; Parkinsonian Disorders; Rats; Rats, Inbred Lew; Rats, Transgenic; RNA, Messenger; RNA, Small Interfering; Rotenone; Substantia Nigra

Therapeutic approaches to slow or block the progression of Parkinson disease (PD) do not exist. Genetic and biochemical studies implicate α-synuclein and leucine-rich repeat kinase 2 (LRRK2) in late-onset PD. LRRK2 kinase activity has been linked to neurodegenerative pathways. However, the therapeutic potential of LRRK2 kinase inhibitors is not clear because significant toxicities have been associated with one class of LRRK2 kinase inhibitors. Furthermore, LRRK2 kinase inhibitors have not been tested previously for efficacy in models of α-synuclein-induced neurodegeneration. To better understand the therapeutic potential of LRRK2 kinase inhibition in PD, we evaluated the tolerability and efficacy of a LRRK2 kinase inhibitor, PF-06447475, in preventing α-synuclein-induced neurodegeneration in rats. Both wild-type rats as well as transgenic G2019S-LRRK2 rats were injected intracranially with adeno-associated viral vectors expressing human α-synuclein in the substantia nigra. Rats were treated with PF-06447475 or a control compound for 4 weeks post-viral transduction. We found that rats expressing G2019S-LRRK2 have exacerbated dopaminergic neurodegeneration and inflammation in response to the overexpression of α-synuclein. Both neurodegeneration and neuroinflammation associated with G2019S-LRRK2 expression were mitigated by LRRK2 kinase inhibition. Furthermore, PF-06447475 provided neuroprotection in wild-type rats. We could not detect adverse pathological indications in the lung, kidney, or liver of rats treated with PF-06447475. These results demonstrate that pharmacological inhibition of LRRK2 is well tolerated for a 4-week period of time in rats and can counteract dopaminergic neurodegeneration caused by acute α-synuclein overexpression.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Dependovirus; Disease Models, Animal; Female; Gene Expression Regulation; Genetic Vectors; Humans; Injections, Intraventricular; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Parkinson Disease; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Pyrimidines; Pyrroles; Rats; Rats, Sprague-Dawley; Signal Transduction; Substantia Nigra

Previous studies demonstrate that intrastriatal injections of fibrillar alpha-synuclein (α-syn) into mice induce Parkinson's disease (PD)-like Lewy body (LB) pathology formed by aggregated α-syn in anatomically interconnected regions and significant nigrostriatal degeneration. The aim of the current study was to evaluate whether exogenous mouse α-syn pre-formed fibrils (PFF) injected into the striatum of rats would result in accumulation of LB-like intracellular inclusions and nigrostriatal degeneration. Sprague-Dawley rats received unilateral intrastriatal injections of either non-fibrillized recombinant α-syn or PFF mouse α-syn in 1- or 2- sites and were euthanized at 30, 60 or 180 days post-injection (pi). Both non-fibrillized recombinant α-syn and PFF α-syn injections resulted in phosphorylated α-syn intraneuronal accumulations (i.e., diffuse Lewy neurite (LN)- and LB-like inclusions) with significantly greater accumulations following PFF injection. LB-like inclusions were observed in several areas that innervate the striatum, most prominently the frontal and insular cortices, the amygdala, and the substantia nigra pars compacta (SNpc). α-Syn accumulations co-localized with ubiquitin, p62, and were thioflavin-S-positive and proteinase-k resistant, suggesting that PFF-induced pathology exhibits properties similar to human LBs. Although α-syn inclusions within the SNpc remained ipsilateral to striatal injection, we observed bilateral reductions in nigral dopamine neurons at the 180-day time-point in both the 1- and 2-site PFF injection paradigms. PFF injected rats exhibited bilateral reductions in striatal dopaminergic innervation at 60 and 180 days and bilateral decreases in homovanillic acid; however, dopamine reduction was observed only in the striatum ipsilateral to PFF injection. Although the level of dopamine asymmetry in PFF injected rats at 180 days was insufficient to elicit motor deficits in amphetamine-induced rotations or forelimb use in the cylinder task, significant disruption of ultrasonic vocalizations was observed. Taken together, our findings demonstrate that α-syn PFF are sufficient to seed the pathological conversion and propagation of endogenous α-syn to induce a progressive, neurodegenerative model of α-synucleinopathy in rats.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Male; Mice; Motor Activity; Nerve Degeneration; Rats; Rats, Sprague-Dawley; Substantia Nigra; Vocalization, Animal

β-Synuclein (β-Syn) is a member of the highly homologous synuclein protein family. The most prominent family member, α-synuclein (α-Syn), abnormally accumulates in so-called Lewy bodies, one of the major pathological hallmarks of α-synucleinopathies. Notably, parts of the peptide backbone, called the nonamyloid component, are also found in amyloid plaques. However, β-Syn seems to have beneficial effects by reducing α-Syn aggregation, and amyloid antiaggregatory activity has been described.. The aim of the study was to analyze if wild-type β-Syn can counteract functional and pathological changes in a murine Alzheimer model over different time periods.. At the onset of pathology, lentiviral particles expressing human β-Syn were injected into the hippocampus of transgenic mice overexpressing human amyloid precursor protein with Swedish and London mutations (APPSL). An empty vector served as the control. Behavioral analyses were performed 1, 3 and 6 months after injection followed by biochemical and histological examinations of brain samples.. β-Syn expression was locally concentrated and rather modest, but nevertheless changed its effect on APP expression and plaque load in a time- and concentration-dependent manner. Interestingly, the phosphorylation of glycogen synthase kinase 3 beta was enhanced in APPSL mice expressing human β-Syn, but an inverse trend was observed in wild-type animals.. The initially reported beneficial effects of β-Syn could be partially reproduced, but locally elevated levels of β-Syn might also cause neurodegeneration. To enlighten the controversial pathological mechanism of β-Syn, further examinations considering the relationship between concentration and exposure time of β-Syn are needed.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Anxiety; beta-Synuclein; Cell Line, Tumor; Disease Models, Animal; Encephalitis; Genetic Vectors; Hippocampus; Humans; Lentivirus; Male; Memory; Mice; Mice, Inbred C57BL; Mice, Transgenic; Proto-Oncogene Proteins c-akt; Signal Transduction

Mutations, duplication and triplication of α-synuclein genes are linked to familial Parkinson's disease (PD), and aggregation of α-synuclein (α-syn) in Lewy bodies (LB) is involved in the pathogenesis of the disease. The targeted overexpression of α-syn in the substantia nigra (SN) mediated by viral vectors may provide a better alternative to recapitulate the neurodegenerative features of PD. Therefore, we overexpressed human wild-type α-syn using rAAV2/1 vectors in the bilateral SN of mouse and examined the effects for up to 12 weeks. Delivery of rAAV-2/1-α-syn caused significant nigrostriatal degeneration including appearance of dystrophic striatal neurites, loss of nigral dopaminergic (DA) neurons and dissolving nigral neuron bodies in a time-dependent manner. In addition, the α-syn overexpressed mice also developed significant deficits in motor function at 12 weeks when the loss of DA neurons exceeded a threshold of 50%. To investigate the sensitivity to neurotoxins in mice overexpressing α-syn, we performed an MPTP treatment with the subacute regimen 8 weeks after rAAV injection. The impact of the combined genetic and environmental insults on DA neuronal loss, striatal dopamine depletion, dopamine turnover and motor dysfunction was markedly greater than that of either alone. Moreover, we observed increased phosphorylation (S129), accumulation and nuclear distribution of α-syn after the combined insults. In summary, these results reveal that the overexpressed α-syn induces progressive nigrostriatal degeneration and increases the susceptibility of DA neurons to MPTP. Therefore, the targeted overexpression of α-syn and the combination with environmental toxins may provide valuable models for understanding PD pathogenesis and developing related therapies.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Genetic Vectors; Humans; Male; Mice; MPTP Poisoning; Parkinson Disease, Secondary; Substantia Nigra

Evidence suggests that accumulation and aggregation of α-synuclein contribute to the pathogenesis of Parkinson's disease (PD). The aim of this study was to evaluate whether diffusion kurtosis imaging (DKI) will provide a sensitive tool for differentiating between α-synuclein-overexpressing transgenic mouse model of PD (TNWT-61) and wild-type (WT) littermates. This experiment was designed as a proof-of-concept study and forms a part of a complex protocol and ongoing translational research. Nine-month-old TNWT-61 mice and age-matched WT littermates underwent behavioral tests to monitor motor impairment and MRI scanning using 9.4 Tesla system in vivo. Tract-based spatial statistics (TBSS) and the DKI protocol were used to compare the whole brain white matter of TNWT-61 and WT mice. In addition, region of interest (ROI) analysis was performed in gray matter regions such as substantia nigra, striatum, hippocampus, sensorimotor cortex, and thalamus known to show higher accumulation of α-synuclein. For the ROI analysis, both DKI (6 b-values) protocol and conventional (2 b-values) diffusion tensor imaging (cDTI) protocol were used. TNWT-61 mice showed significant impairment of motor coordination. With the DKI protocol, mean, axial, and radial kurtosis were found to be significantly elevated, whereas mean and radial diffusivity were decreased in the TNWT-61 group compared to that in the WT controls with both TBSS and ROI analysis. With the cDTI protocol, the ROI analysis showed decrease in all diffusivity parameters in TNWT-61 mice. The current study provides evidence that DKI by providing both kurtosis and diffusivity parameters gives unique information that is complementary to cDTI for in vivo detection of pathological changes that underlie PD-like symptomatology in TNWT-61 mouse model of PD. This result is a crucial step in search for a candidate diagnostic biomarker with translational potential and relevance for human studies.

Topics: alpha-Synuclein; Animals; Brain; Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging; Disease Models, Animal; Humans; Male; Mice; Mice, Transgenic; Motor Activity; Parkinson Disease; Pilot Projects

Brain derived neurotrophic factor (BDNF) signaling disturbances in Alzheimer׳s disease (AD) have been demonstrated. BDNF levels fall in AD, but the ratio between truncated and full-length BDNF receptors TrkB.T1 and TrkB.TK, respectively, increases in brains of AD patients and APPswe/PS1dE9 (APP/PS1) AD model mice. Dopaminergic (DAergic) system disturbances in AD and detrimental effects of BDNF signaling deficits on DAergic system functions have also been indicated. Against this, we investigated changes in nigrostriatal dopamine (DA) system in mice carrying APP/PS1 and/or TrkB.T1 transgenes, the latter line modeling the TrkB.T1/TK ratio change in AD. Employing in vivo voltammetry, we found normal short-term DA release in caudate-putamen of mice carrying APP/PS1 or TrkB.T1 transgenes but impaired capacity to recruit more DA upon prolonged stimulation. However, mice carrying both transgenes did not differ from wild-type controls. Immunohistochemistry revealed normal density of tyrosine hydroxylase positive axon terminals in caudate-putamen in all genotypes and intact presynaptic machinery for DA release and reuptake, as shown by unchanged levels of SNAP-25, α-synuclein and DA transporter. However, we observed increased DAergic neurons in substantia nigra of TrkB.T1 mice resulting in decreased tyrosine hydroxylase per neuron in TrkB.T1 mice. The finding of unchanged nigral DAergic neurons in APP/PS1 mice largely confirms earlier reports, but the unexpected increase in midbrain DA neurons in TrkB.T1 mice is a novel finding. We suggest that both APP/PS1 and TrkB.T1 genotypes disrupt DAergic signaling, but via separate mechanisms.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Brain-Derived Neurotrophic Factor; Corpus Striatum; Disease Models, Animal; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopaminergic Neurons; Humans; Male; Mesencephalon; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Presenilin-1; Receptor, trkB; Synaptosomal-Associated Protein 25; Tyrosine 3-Monooxygenase

Vector based over-expression of α-synuclein is a newly developed method to establish animal Parkinson's disease (PD) model. In this paper, we inject the rat brain with recombinant adeno-associated virus (rAAV) to express α-synuclein wild-type and A53T mutation, and compared the degeneration of dopaminergic neurons between them.. The rAAV vectors were injected into the substantia nigra pars compacta (SNpc) of rat brain. In different time point, immunohistochemistry was used to detect the expression of α-synuclein. The expression level was lower in the 3rd and 6th week and increased from the 9th week. α-synuclein spread around the neurons in SNpc in the 12th week. The loss of dopaminergic neurons was increasing along the expression of α-synuclein, and damage extent was more serious in the A53T group than the WT group. In the A53T group, there were more insoluble inclusions can be detected, and the phosphorylation of α-synuclein was also higher.. The result of comparison between the two types of α-synuclein showed that A53T mutated α-synuclein was more effective to establish PD model, and the model based A53T mutated α-synuclein was a suitable model to early-onset PD.

Topics: Age Factors; alpha-Synuclein; Amino Acid Substitution; Animals; Apomorphine; Brain; Disease Models, Animal; Dopaminergic Neurons; Immunohistochemistry; Male; Mutant Proteins; Mutation, Missense; Parkinsonian Disorders; Phosphorylation; Protein Aggregation, Pathological; Rats; Rats, Transgenic; Rats, Wistar; Recombinant Proteins; Torsion Abnormality

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disease. Post-mortem hallmarks of MSA neuropathology include oligodendroglial α-synuclein (αSYN) inclusions, striatonigral degeneration, olivopontocerebellar atrophy, and increased microglial activation that accompanies the wide spread neurodegeneration. Recently, we demonstrated upregulation of myeloperoxidase (MPO) in activated microglia and provided evidence for the role of microglial MPO in the mediation of MSA-like neurodegeneration (Stefanova et al. Neurotox Res 21:393-404, 2015). The aim of the current study was to assess the therapeutic potency of MPO inhibition (MPOi) in a model of advanced MSA. We replicated the advanced pathology of MSA by intoxicating transgenic PLP-α-synuclein transgenic mice with 3-nitropropionic acid (3NP). After onset of the full-blown pathology, MSA mice received either MPOi or vehicle over 3 weeks. Motor phenotype and neuropathology were analyzed to assess the therapeutic efficacy of MPOi compared to vehicle treatment in MSA mice. MPOi therapy initiated after the onset of severe MSA-like neuropathology in mice failed to attenuate motor impairments and neuronal loss within the striatum, substantia nigra pars compacta, inferior olives, pontine nuclei, and cerebellar cortex. However, we observed a significant reduction of microglial activation in degenerating brain areas. Further, nitrated αSYN accumulation was reduced in the striatonigral region. In summary, delayed-start MPOi treatment reduced microglial activation and levels of nitrated αSYN in a mouse model of advanced MSA. These effects failed to impact on motor impairments and neuronal loss in contrast to previously reported disease modifying efficacy of early-start therapy with MPOi in MSA.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Enzyme Inhibitors; Humans; Male; Mice, Transgenic; Microglia; Motor Activity; Multiple System Atrophy; Myelin Proteolipid Protein; Neurons; Neuroprotective Agents; Nitro Compounds; Peroxidase; Propionates; Pyrimidinones; Pyrroles; Severity of Illness Index; Treatment Outcome

Parkinson's disease, neuropathologically defined by the aggregation of α-synuclein, is characterized by neuropsychiatric symptoms such as depression and anxiety preceding the onset of motor symptoms. A loss of serotonergic neurons or their projections into the hippocampus and alterations in serotonin release may be linked to these symptoms. Here, we investigate the effect of human A53T α-synuclein on serotonergic neurons using 12-months-old transgenic mice. We detected human α-synuclein in the perikarya of brainstem median and dorsal raphe neurons as well as in serotonergic fibers in the hippocampus. Despite intracellular α-synuclein accumulation there was no loss of serotonergic neurons in dorsal and median raphe nuclei of A53T α-synuclein mice. However, serotonin levels were significantly reduced in the brainstem. In addition, serotonergic fiber density in the dorsal dentate gyrus was significantly less dense in transgenic mice. Interestingly, we detected a significantly compromised increase in doublecortin+ neuroblasts after chronic treatment with fluoxetine at the site of reduced serotonergic innervation, the infrapyramidal blade of the dorsal dentate gyrus in A53T α-synuclein mice. This suggests that α-synuclein affects serotonergic projections in a spatially distinct pattern within the hippocampus thereby influencing the response to antidepressant treatment.

Topics: alpha-Synuclein; Animals; Brain Stem; Disease Models, Animal; Hippocampus; Humans; Mice; Mice, Transgenic; Mutation; Parkinson Disease; Serotonergic Neurons; Serotonin

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons as well as the presence of proteinaceous inclusions named Lewy bodies. α-synuclein (α-syn) is a major constituent of Lewy bodies, and the first disease-causing protein characterized in PD. Several α-syn-based animal models of PD have been developed to investigate the pathophysiology of PD, but none of them recapitulate the full picture of the disease. Ageing is the most compelling and major risk factor for developing PD but its impact on α-syn toxicity remains however unexplored. In this study, we developed and exploited a recombinant adeno-associated viral (AAV) vector of serotype 9 overexpressing mutated α-syn to elucidate the influence of ageing on the dynamics of PD-related neurodegeneration associated with α-syn pathology in different mammalian species.. Identical AAV pseudotype 2/9 vectors carrying the DNA for human mutant p.A53T α-syn were injected into the substantia nigra to induce neurodegeneration and synucleinopathy in mice, rats and monkeys. Rats were used first to validate the ability of this serotype to replicate α-syn pathology and second to investigate the relationship between the kinetics of α-syn-induced nigrostriatal degeneration and the progressive onset of motor dysfunctions, strikingly reminiscent of the impairments observed in PD patients. In mice, AAV2/9-hα-syn injection into the substantia nigra was associated with accumulation of α-syn and phosphorylated hα-syn, regardless of mouse strain. However, phenotypic mutants with either accelerated senescence or resistance to senescence did not display differential susceptibility to hα-syn overexpression. Of note, p-α-syn levels correlated with nigrostriatal degeneration in mice. In monkeys, hα-syn-induced degeneration of the nigrostriatal pathway was not affected by the age of the animals. Unlike mice, monkeys did not exhibit correlations between levels of phosphorylated α-syn and neurodegeneration.. In conclusion, AAV2/9-mediated hα-syn induces robust nigrostriatal neurodegeneration in mice, rats and monkeys, allowing translational comparisons among species. Ageing, however, neither exacerbated nigrostriatal neurodegeneration nor α-syn pathology per se. Our unprecedented multi-species investigation thus favours the multiple-hit hypothesis for PD wherein ageing would merely be an aggravating, additive, factor superimposed upon an independent disease process.

Topics: Aging; alpha-Synuclein; Animals; Biomechanical Phenomena; Callithrix; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; Green Fluorescent Proteins; Humans; Mice; Motor Activity; MPTP Poisoning; Principal Component Analysis; Psychomotor Performance; Rats; Striatonigral Degeneration; Substantia Nigra; Time Factors; Transduction, Genetic; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a movement disorder due to the loss of dopaminergic (DA) neurons in the substantia nigra. Alpha-synuclein phosphorylation and α-synuclein inclusion (Lewy body) become a main contributor, but little is known about their formation mechanism. Here we used protein expression profiling of PD to construct a model of their signalling network from drsophila to human and nominate major nodes that regulate PD development. We found in this network that LK6, a serine/threonine protein kinase, plays a key role in promoting α-synuclein Ser129 phosphorylation by identification of LK6 knockout and overexpression. In vivo test was further confirmed that LK6 indeed enhances α-synuclein phosphorylation, accelerates the death of dopaminergic neurons, reduces the climbing ability and shortens the the life span of drosophila. Further, MAP kinase-interacting kinase 2a (Mnk2a), a human homolog of LK6, also been shown to make α-synuclein phosphorylation and leads to α-synuclein inclusion formation. On the mechanism, the phosphorylation mediated by LK6 and Mnk2a is controlled through ERK signal pathway by phorbolmyristate acetate (PMA) avtivation and PD98059 inhibition. Our findings establish pivotal role of Lk6 and Mnk2a in unprecedented signalling networks, may lead to new therapies preventing α-synuclein inclusion formation and neurodegeneration.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Drosophila Proteins; Female; Male; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase Kinases; Nerve Degeneration; Parkinson Disease; Phosphorylation; Phosphotransferases; Signal Transduction; Substantia Nigra

Parkinson's disease (PD) is a progressive neurodegenerative disease that leads to a wide range of motor and nonmotor deficits. Specifically, voice and swallow deficits manifest early, are devastating to quality of life, and are difficult to treat with standard medical therapies. The pathological hallmarks of PD include accumulation of the presynaptic protein α-synuclein (αSyn) as well as degeneration of substantia nigra dopaminergic neurons. However, there is no clear understanding of how or when this pathology contributes to voice and swallow dysfunction in PD. The present study evaluates the effect of loss of function of the phosphatase and tensin homolog-induced putative kinase 1 gene in rats (PINK1(-/-) ), a model of autosomal recessive PD in humans, on vocalization, oromotor and limb function, and neurodegenerative pathologies. Behavioral measures include ultrasonic vocalizations, tongue force, biting, and gross motor performance that are assayed at 2, 4, 6, and 8 months of age. Aggregated αSyn and tyrosine hydroxylase immunoreactivity (TH-ir) were measured at 8 months. We show that, compared with wild-type controls, PINK1(-/-) rats develop (1) early and progressive vocalization and oromotor deficits, (2) reduced TH-ir in the locus coeruleus that correlates with vocal loudness and tongue force, and (3) αSyn neuropathology in brain regions important for cranial sensorimotor control. This novel approach of characterizing a PINK1(-/-) genetic model of PD provides the foundational work required to define behavioral biomarkers for the development of disease-modifying therapeutics for PD patients.

Topics: alpha-Synuclein; Animals; Ataxia; Brain; Disease Models, Animal; Gene Knockout Techniques; Immunohistochemistry; Male; Motor Activity; Muscle Strength; Parkinson Disease; Protein Kinases; Rats; Rats, Long-Evans; Tongue; Tyrosine 3-Monooxygenase; Vocalization, Animal

Autophagy is involved in the pathogenesis of neurodegenerative diseases including Parkinson disease (PD). However, little is known about the regulation of autophagy in neurodegenerative process. In this study, we characterized aberrant activation of autophagy induced by neurotoxin 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) and demonstrated that melatonin has a protective effect on neurotoxicity. We found an excessive activation of autophagy in monkey brain tissues and C6 cells, induced by MPTP, which is mediated by CDK5 (cyclin-dependent kinase 5). MPTP treatment significantly reduced total dendritic length and dendritic complexity of cultured primary cortical neurons and melatonin could reverse this effect. Decreased TH (tyrosine hydroxylase)-positive cells and dendrites of dopaminergic neurons in the substantia nigra pars compacta (SNc) were observed in MPTP-treated monkeys and mice. Along with decreased TH protein level, we observed an upregulation of CDK5 and enhanced autophagic activity in the striatum of mice with MPTP injection. These changes could be salvaged by melatonin treatment or knockdown of CDK5. Importantly, melatonin or knockdown of CDK5 reduced MPTP-induced SNCA/α-synuclein aggregation in mice, which is widely thought to trigger the pathogenesis of PD. Finally, melatonin or knockdown of CDK5 counteracted the PD phenotype in mice induced by MPTP. Our findings uncover a potent role of CDK5-mediated autophagy in the pathogenesis of PD, and suggest that control of autophagic pathways may provide an important clue for exploring potential target for novel therapeutics of PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Autophagy; Cyclin-Dependent Kinase 5; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Haplorhini; Melatonin; Mice; Neurotoxins; Parkinson Disease

The accumulation of mis-folded and/or abnormally modified proteins is a major characteristic of many neurodegenerative diseases. In Lewy body disease (LBD), which includes Parkinson's disease and dementia with Lewy bodies, insoluble α-synuclein is widely deposited in the presynaptic terminals as well as in the neuronal cytoplasm in distinct brain regions. It is well known that the autophagy-lysosome system serves as an efficient degradation pathway for abnormal molecules within cells. To test the possibility that activated autophagy can degrade abnormal molecules, we investigated the effect of trehalose on abnormal aggregation of α-synuclein in a model of LBD. Trehalose is a natural disaccharide composed of two glucose units and functions as an autophagy inducer. Consistent with previous studies, trehalose increased level of the autophagosomal protein LC3, especially a lipidated form LC3-II in cultured cells and mice brain. Also, trehalose increased levels of several chaperon molecules, such as HSP90 and SigmaR1, in the brains of LBD model mice. Further studies revealed that level of detergent-insoluble α-synuclein was suppressed in mice following oral administration of trehalose, despite an apparent alteration was not observed regarding abnormal aggregation of α-synuclein. These results suggest that the oral intake of trehalose modulates propensity of molecules prior to aggregation formation.

Topics: Administration, Oral; alpha-Synuclein; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Brain; Disease Models, Animal; HeLa Cells; HSP90 Heat-Shock Proteins; Humans; Lewy Body Disease; Maltose; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; Molecular Chaperones; Protein Aggregation, Pathological; Receptors, sigma; Sigma-1 Receptor; Solubility; Trehalose

Abnormal accumulation of amyloid β (Aβ), α-synuclein (α-syn), and microtubule-associated protein tau (tau) have been implicated in neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and Pick's disease (PiD). The mechanisms through which aggregated versions of α-syn, Aβ, and tau may lead to neurodegeneration are not entirely clear, however, there is emerging evidence that neuronal calcium dysregulation is at play. Two-photon microscopy is a powerful tool that can be used to measure in vivo alterations of calcium transients using animal models of neurodegeneration, and when coupled with statistical methods to characterize functional signals, can reveal features that identify and discern between distinct mouse types. We studied four mouse models of neurodegenerative diseases, wild-type (WT) α-syn, E57K α-syn, amyloid precursor protein (APP), and triple-repeat (3R)-Tau and Non-transgenic (tg) littermates using two-photon microscopy. We found that for calcium transients, simple measures such as area under the curve (AUC) and peak width in the 1-Hz whisker pad stimulation paradigm, were significantly increased for WT α-syn, E57K α-syn and APP mice across all cortical depths compared to Non-tg mice. A similar result was found in the 3-Hz paradigm in E57K α-syn mice. Spontaneous calcium transient AUC was significantly higher in WT α-syn mice and lower for APP and 3R Tau mice at 150-μm depth. Going beyond simple measure differences such as group means for AUC, signal peak width, and spontaneous calcium activity counts, we built statistical classifiers to characterize neuronal calcium signals to identify and discern, with quantified measures of confidence, all mouse types. We tested our classifier with FK506, which regulates mitochondrial calcium and found that this drug modulated the WT α-syn calcium transients to such an extent that the classifier easily identified the calcium transients as belonging to Non-tg mice. The coupling of two-photon microscopy data and statistical classifiers serves to effectively create a bioassay where the number of animals and scientific resources can be reduced without compromising the results of the experiment.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Calcineurin Inhibitors; Calcium Signaling; Cluster Analysis; Disease Models, Animal; Female; Mice; Mice, Transgenic; Neurodegenerative Diseases; Physical Stimulation; ROC Curve; Somatosensory Cortex; Tacrolimus; tau Proteins; Vibrissae

Parkinson's disease (PD) is a prevalent neurodegenerative disorder with pathological features including death of dopaminergic neurons in the substantia nigra and intraneuronal accumulations of Lewy bodies. As the main component of Lewy bodies, α-synuclein is implicated in PD pathogenesis by aggregation into insoluble filaments. However, the detailed mechanisms underlying α-synuclein induced neurotoxicity in PD are still elusive. MicroRNAs are ~20nt small RNA molecules that fine-tune gene expression at posttranscriptional level. A plethora of miRNAs have been found to be dysregulated in the brain and blood cells of PD patients. Nevertheless, the detailed mechanisms and their in vivo functions in PD still need further investigation. By using Drosophila PD model expressing α-synuclein A30P, we examined brain miRNA expression with high-throughput small RNA sequencing technology. We found that five miRNAs (dme-miR-133-3p, dme-miR-137-3p, dme-miR-13b-3p, dme-miR-932-5p, dme-miR-1008-5p) were upregulated in PD flies. Among them, miR-13b, miR-133, miR-137 are brain enriched and highly conserved from Drosophila to humans. KEGG pathway analysis using DIANA miR-Path demonstrated that neuroactive-ligand receptor interaction pathway was most likely affected by these miRNAs. Interestingly, miR-137 was predicted to regulate most of the identified targets in this pathway, including dopamine receptor (DopR, D2R), γ-aminobutyric acid (GABA) receptor (GABA-B-R1, GABA-B-R3) and N-methyl-D-aspartate (NMDA) receptor (Nmdar2). The validation experiments showed that the expression of miR-137 and its targets was negatively correlated in PD flies. Further experiments using luciferase reporter assay confirmed that miR-137 could act on specific sites in 3' UTR region of D2R, Nmdar2 and GABA-B-R3, which downregulated significantly in PD flies. Collectively, our findings indicate that α-synuclein could induce the dysregulation of miRNAs, which target neuroactive ligand-receptor interaction pathway in vivo. We believe it will help us further understand the contribution of miRNAs to α-synuclein neurotoxicity and provide new insights into the pathogenesis driving PD.

Topics: 3' Untranslated Regions; alpha-Synuclein; Animals; Computational Biology; Disease Models, Animal; Drosophila; Female; Gene Expression Profiling; Gene Expression Regulation; High-Throughput Nucleotide Sequencing; Locomotion; Male; MicroRNAs; Molecular Sequence Annotation; Parkinson Disease; Receptors, Neurotransmitter; Reproducibility of Results; RNA Interference; RNA, Messenger; Signal Transduction

Alpha-synuclein (αSyn) plays a central role in the pathogenesis of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Recent multicenter genetic studies have revealed that mutations in the glucocerebrosidase 1 (GBA1) gene, which are responsible for Gaucher's disease, are strong risk factors for PD and DLB. However, the mechanistic link between the functional loss of glucocerebrosidase (GCase) and the toxicity of αSyn in vivo is not fully understood. In this study, we employed Drosophila models to examine the effect of GCase deficiency on the neurotoxicity of αSyn and its molecular mechanism. Behavioral and histological analyses showed that knockdown of the Drosophila homolog of GBA1 (dGBA1) exacerbates the locomotor dysfunction, loss of dopaminergic neurons and retinal degeneration of αSyn-expressing flies. This phenotypic aggravation was associated with the accumulation of proteinase K (PK)-resistant αSyn, rather than with changes in the total amount of αSyn, raising the possibility that glucosylceramide (GlcCer), a substrate of GCase, accelerates the misfolding of αSyn. Indeed, in vitro experiments revealed that GlcCer directly promotes the conversion of recombinant αSyn into the PK-resistant form, representing a toxic conformational change. Similar to dGBA1 knockdown, knockdown of the Drosophila homolog of β-galactosidase (β-Gal) also aggravated locomotor dysfunction of the αSyn flies, and its substrate GM1 ganglioside accelerated the formation of PK-resistant αSyn. Our findings suggest that the functional loss of GCase or β-Gal promotes the toxic conversion of αSyn via aberrant interactions between αSyn and their substrate glycolipids, leading to the aggravation of αSyn-mediated neurodegeneration.

Topics: alpha-Synuclein; Animals; beta-Galactosidase; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Endopeptidase K; Gene Knockdown Techniques; Glucosylceramidase; Glucosylceramides; Humans; Male; Parkinsonian Disorders; Protein Aggregation, Pathological; Protein Folding

Parkinson's disease (PD) is a neurodegenerative disorder characterized by a progressive loss of nigral dopaminergic neurons and by the presence of aggregates containing α-synuclein called Lewy bodies. Viral vector-induced overexpression of α-synuclein in dopaminergic neurons represents a model of PD which recapitulates disease progression better than commonly used neurotoxin models. Previous studies using this model have reported motor and cognitive impairments, whereas depression, mood and anxiety phenotypes are less described. To investigate these psychiatric phenotypes, Sprague-Dawley rats received bilateral injections of a recombinant adeno-associated virus (AAV) vector expressing human α-synuclein or GFP into the substantia nigra pars compacta. Behavior was assessed at two timepoints: 3 and 8 weeks post-injection. We report that nigral α-synuclein overexpression led to a pronounced nigral dopaminergic cell loss accompanied by a smaller cell loss in the ventral tegmental area, and to a decreased striatal density of dopaminergic fibers. The AAV-α-synuclein group exhibited modest, but significant motor impairments 8 weeks after vector administration. The AAV-α-synuclein group displayed depressive-like behavior in the forced swim test after 3 weeks, and reduced sucrose preference at week 8. At both timepoints, overexpression of α-synuclein was linked to a hyperactive hypothalamic-pituitary-adrenal (HPA) axis regulation of corticosterone. The depressive-like phenotype was also correlated with decreased nigral brain-derived neurotrophic factor and spinophilin levels, and with decreased striatal levels of the activity-regulated cytoskeleton-associated protein. This study demonstrates that AAV-mediated α-synuclein overexpression in dopamine neurons is not only useful to model motor impairments of PD, but also depression. This study also provides evidence that depression in experimental Parkinsonism is correlated to dysregulation of the HPA axis and to alterations in proteins involved in synaptic plasticity.

Topics: Adrenocorticotropic Hormone; alpha-Synuclein; Animals; Corticosterone; Dependovirus; Depression; Disease Models, Animal; Dopaminergic Neurons; Female; Food Preferences; Gene Expression Regulation; Humans; Longitudinal Studies; Maze Learning; Mesencephalon; Phenotype; Psychomotor Performance; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Stress, Psychological; Swimming; Time Factors

Autosomal recessively inherited glucocerebrosidase 1 (GBA1) mutations cause the lysosomal storage disorder Gaucher's disease (GD). Heterozygous GBA1 mutations (GBA1(+/-)) are the most common risk factor for Parkinson's disease (PD). Previous studies typically focused on the interaction between the reduction of glucocerebrosidase (enzymatic) activity in GBA1(+/-) carriers and alpha-synuclein-mediated neurotoxicity. However, it is unclear whether other mechanisms also contribute to the increased risk of PD in GBA1(+/-) carriers. The zebrafish genome does not contain alpha-synuclein (SNCA), thus providing a unique opportunity to study pathogenic mechanisms unrelated to alpha-synuclein toxicity. Here we describe a mutant zebrafish line created by TALEN genome editing carrying a 23 bp deletion in gba1 (gba1(c.1276_1298del)), the zebrafish orthologue of human GBA1. Marked sphingolipid accumulation was already detected at 5 days post-fertilization with accompanying microglial activation and early, sustained up-regulation of miR-155, a master regulator of inflammation. gba1(c.1276_1298del) mutant zebrafish developed a rapidly worsening phenotype from 8 weeks onwards with striking reduction in motor activity by 12 weeks. Histopathologically, we observed marked Gaucher cell invasion of the brain and other organs. Dopaminergic neuronal cell count was normal through development but reduced by >30% at 12 weeks in the presence of ubiquitin-positive, intra-neuronal inclusions. This gba1(c.1276_1298del) zebrafish line is the first viable vertebrate model sharing key pathological features of GD in both neuronal and non-neuronal tissue. Our study also provides evidence for early microglial activation prior to alpha-synuclein-independent neuronal cell death in GBA1 deficiency and suggests upregulation of miR-155 as a common denominator across different neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Cell Death; Disease Models, Animal; Gaucher Disease; Glucosylceramidase; Microglia; MicroRNAs; Neurons; Sequence Deletion; Up-Regulation; Zebrafish; Zebrafish Proteins

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Parkinson Disease; Serotonergic Neurons; Serotonin

Diminished lysosomal function can lead to abnormal cellular accumulation of specific proteins, including α-synuclein, contributing to disease pathogenesis of vulnerable neurons in Parkinson's disease (PD) and related α-synucleinopathies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase (GCase), and mutations in GBA1 are a prominent genetic risk factor for PD. Previous studies showed that in sporadic PD, and in normal aging, GCase brain activity is reduced and levels of corresponding glycolipid substrates are increased. The present study tested whether increasing GCase through AAV-GBA1 intra-cerebral gene delivery in two PD rodent models would reduce the accumulation of α-synuclein and protect midbrain dopamine neurons from α-synuclein-mediated neuronal damage. In the first model, transgenic mice overexpressing wildtype α-synuclein throughout the brain (ASO mice) were used, and in the second model, a rat model of selective dopamine neuron degeneration was induced by AAV-A53T mutant α-synuclein. In ASO mice, intra-cerebral AAV-GBA1 injections into several brain regions increased GCase activity and reduced the accumulation of α-synuclein in the substantia nigra and striatum. In rats, co-injection of AAV-GBA1 with AAV-A53T α-synuclein into the substantia nigra prevented α-synuclein-mediated degeneration of nigrostriatal dopamine neurons by 6 months. These neuroprotective effects were associated with altered protein expression of markers of autophagy. These experiments demonstrate, for the first time, the neuroprotective effects of increasing GCase against dopaminergic neuron degeneration, and support the development of therapeutics targeting GCase or other lysosomal genes to improve neuronal handling of α-synuclein.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Genetic Therapy; Genetic Vectors; Glucosylceramidase; Humans; Male; Mesencephalon; Mice, Transgenic; Neurodegenerative Diseases; Rats, Sprague-Dawley

Multiple system atrophy (MSA) is a progressive, neurodegenerative disease characterized by parkinsonism, resistance to dopamine therapy, ataxia, autonomic dysfunction, and pathological accumulation of α-synuclein (α-syn) in oligodendrocytes. Neurosin (kallikrein-6) is a serine protease capable of cleaving α-syn in the CNS, and we have previously shown that lentiviral (LV) vector delivery of neurosin into the brain of a mouse model of dementia with Lewy body/ Parkinson's disease reduces the accumulation of α-syn and improves neuronal synaptic integrity.. In this study, we investigated the ability of a modified, systemically delivered neurosin to reduce the levels of α-syn in oligodendrocytes and reduce the cell-to-cell spread of α-syn to glial cells in a mouse model of MSA (MBP-α-syn). We engineered a viral vector that expresses a neurosin genetically modified for increased half-life (R80Q mutation) that also contains a brain-targeting sequence (apoB) for delivery into the CNS. Peripheral administration of the LV-neurosin-apoB to the MBP-α-syn tg model resulted in accumulation of neurosin-apoB in the CNS, reduced accumulation of α-syn in oligodendrocytes and astrocytes, improved myelin sheath formation in the corpus callosum and behavioral improvements.. Thus, the modified, brain-targeted neurosin may warrant further investigation as potential therapy for MSA.

Topics: alpha-Synuclein; Animals; Astrocytes; Behavior, Animal; Cells, Cultured; Disease Models, Animal; Kallikreins; Mice; Multiple System Atrophy; Oligodendroglia; Parkinson Disease

The development of effective neuroprotective therapies for Parkinson's disease (PD) has been severely hindered by the notable lack of an appropriate animal model for preclinical screening. Indeed, most models currently available are either acute in nature or fail to recapitulate all characteristic features of the disease. Here, we present a novel progressive model of PD, with behavioural and cellular features that closely approximate those observed in patients. Chronic exposure to dietary phytosterol glucosides has been found to be neurotoxic. When fed to rats, β-sitosterol β-d-glucoside (BSSG) triggers the progressive development of parkinsonism, with clinical signs and histopathology beginning to appear following cessation of exposure to the neurotoxic insult and continuing to develop over several months. Here, we characterize the progressive nature of this model, its non-motor features, the anatomical spread of synucleinopathy, and response to levodopa administration. In Sprague Dawley rats, chronic BSSG feeding for 4 months triggered the progressive development of a parkinsonian phenotype and pathological events that evolved slowly over time, with neuronal loss beginning only after toxin exposure was terminated. At approximately 3 months following initiation of BSSG exposure, animals displayed the early emergence of an olfactory deficit, in the absence of significant dopaminergic nigral cell loss or locomotor deficits. Locomotor deficits developed gradually over time, initially appearing as locomotor asymmetry and developing into akinesia/bradykinesia, which was reversed by levodopa treatment. Late-stage cognitive impairment was observed in the form of spatial working memory deficits, as assessed by the radial arm maze. In addition to the progressive loss of TH+ cells in the substantia nigra, the appearance of proteinase K-resistant intracellular α-synuclein aggregates was also observed to develop progressively, appearing first in the olfactory bulb, then the striatum, the substantia nigra and, finally, hippocampal and cortical regions. The slowly progressive nature of this model, together with its construct, face and predictive validity, make it ideal for the screening of potential neuroprotective therapies for the treatment of PD.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Motor Activity; Neurons; Parkinson Disease, Secondary; Rats; Rats, Sprague-Dawley; Sitosterols

Neurodegenerative diseases have been linked to inflammation, but whether altered immunomodulation plays a causative role in neurodegeneration is not clear. We show that lack of cytokine interferon-β (IFN-β) signaling causes spontaneous neurodegeneration in the absence of neurodegenerative disease-causing mutant proteins. Mice lacking Ifnb function exhibited motor and cognitive learning impairments with accompanying α-synuclein-containing Lewy bodies in the brain, as well as a reduction in dopaminergic neurons and defective dopamine signaling in the nigrostriatal region. Lack of IFN-β signaling caused defects in neuronal autophagy prior to α-synucleinopathy, which was associated with accumulation of senescent mitochondria. Recombinant IFN-β promoted neurite growth and branching, autophagy flux, and α-synuclein degradation in neurons. In addition, lentiviral IFN-β overexpression prevented dopaminergic neuron loss in a familial Parkinson's disease model. These results indicate a protective role for IFN-β in neuronal homeostasis and validate Ifnb mutant mice as a model for sporadic Lewy body and Parkinson's disease dementia.

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Genetic Therapy; Interferon-beta; Lewy Body Disease; Mice; Mice, Inbred C57BL; Neurons; Parkinson Disease; Receptor, Interferon alpha-beta; Signal Transduction; Transcriptome

Parkinson disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopamine neurons in the substantia nigra pars compacta (SNpc) and widespread aggregates of the protein alpha-synuclein (α-syn). Increasing evidence points to inflammation as a chief mediator; however, the role of α-syn in triggering and sustaining inflammation remains unclear. In models of Alzheimer's disease (AD), multiple sclerosis (MS) and neurotoxin models of PD, the chemokine CX3CL1 (fractalkine) and its receptor (CX3CR1) have important roles in modulating neuroinflammation.. To examine the role of fractalkine signaling in α-syn-induced-neuroinflammation and neurodegeneration, we used an in vivo mouse model in which human α-syn is overexpressed by an adeno associated viral vector serotype 2 (AAV2) and in vitro phagocytosis and protein internalization assays with primary microglia treated with aggregated α-syn.. We observed that loss of CX3CR1 expression led to a reduced inflammatory response, with reduced IgG deposition and expression of MHCII 4 weeks post-transduction. Six months post transduction, AAV2 mediated overexpression of α-syn leads to loss of dopaminergic neurons, and this loss was not exacerbated in animals with deletion of CX3CR1. To determine the mechanism by which CX3CR1affects inflammatory responses in α-syn-induced inflammation, phagocytosis was assessed using a fluorescent microsphere assay as well as by microglial uptake of aggregated α-syn. CX3CR1-/- microglia showed reduced uptake of fluorescent beads and aggregated α-syn.. Our results suggest that one mechanism by which CX3CR1-/- attenuates inflammation is at the level of phagocytosis of aggregated α-syn by microglia. These data implicate fractalkine signaling as a potential therapeutic target for regulating inflammatory response in α-syn models PD.

Topics: alpha-Synuclein; Animals; Chemokine CX3CL1; CX3C Chemokine Receptor 1; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Gene Knockout Techniques; Genetic Vectors; Humans; Mice; Microglia; Parkinson Disease; Phagocytosis; Receptors, Chemokine

Multiple system atrophy (MSA) is a fatal, rapidly progressive neurodegenerative disease with (oligodendro-)glial cytoplasmic α-synuclein (α-syn) inclusions (GCIs). Peripheral neuropathies have been reported in up to 40% of MSA patients, the cause remaining unclear. In a transgenic MSA mouse model featuring GCI-like inclusion pathology based on PLP-promoter driven overexpression of human α-syn in oligodendroglia motor and non-motor deficits are associated with MSA-like neurodegeneration. Since α-syn is also expressed in Schwann cells we aimed to investigate whether peripheral nerves are anatomically and functionally affected in the PLP-α-syn MSA mouse model.. To this end, heat/cold as well as mechanical sensitivity tests were performed. Furthermore, in vivo and ex vivo nerve conduction and the G-ratios of the sciatic nerve were analyzed, and thermosensitive ion channel mRNA expression in dorsal root ganglia (DRG) was assessed. The presence of human α-syn in Schwann cells was associated with subtle behavioral impairments. The G-ratio of the sciatic nerve, the conduction velocity of myelinated and unmyelinated primary afferents and the expression of thermosensitive ion channels in the sensory neurons, however, were similar to wildtype mice.. Our results suggest that the PNS appears to be affected by Schwann cell α-syn deposits in the PLP-α-syn MSA mouse model. However, there was no consistent evidence for functional PNS perturbations resulting from such α-syn aggregates suggesting a more central cause of the observed behavioral abnormalities. Nonetheless, our results do not exclude a causal role of α-syn in the pathogenesis of MSA associated peripheral neuropathy.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Cold Temperature; Disease Models, Animal; Fluorescent Antibody Technique; Ganglia, Spinal; Gene Expression Regulation; Hot Temperature; Humans; Male; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Multiple System Atrophy; Myelin Proteolipid Protein; Neural Conduction; Phenotype; RNA, Messenger; Schwann Cells; Sciatic Nerve; Time Factors; Transient Receptor Potential Channels; TRPA1 Cation Channel; TRPM Cation Channels

Few preclinical studies have assessed the long-term neuropathology and behavioral deficits after sustaining blast-induced neurotrauma (BINT). Previous studies have shown extensive astrogliosis and cell death at acute stages (<7 days) but the temporal response at a chronic stage has yet to be ascertained. Here, we used behavioral assays, immmunohistochemistry and neurochemistry in limbic areas such as the amygdala (Amy), Hippocampus (Hipp), nucleus accumbens (Nac), and prefrontal cortex (PFC), to determine the long-term effects of a single blast exposure. Behavioral results identified elevated avoidance behavior and decreased short-term memory at either one or three months after a single blast event. At three months after BINT, markers for neurodegeneration (FJB) and microglia activation (Iba-1) increased while index of mature neurons (NeuN) significantly decreased in all brain regions examined. Gliosis (GFAP) increased in all regions except the Nac but only PFC was positive for apoptosis (caspase-3). At three months, tau was selectively elevated in the PFC and Hipp whereas α-synuclein transiently increased in the Hipp at one month after blast exposure. The composite neurochemical measure, myo-inositol+glycine/creatine, was consistently increased in each brain region three months following blast. Overall, a single blast event resulted in enduring long-term effects on behavior and neuropathological sequelae.

Topics: alpha-Synuclein; Amygdala; Animals; Apoptosis; Brain Injuries; Caspase 3; Disease Models, Animal; Gliosis; Hippocampus; Male; Memory, Short-Term; Neurodegenerative Diseases; Neurons; Nucleus Accumbens; Prefrontal Cortex; Rats; Rats, Sprague-Dawley

The neurodegenerative synucleinopathies, which include Parkinson disease, multiple-system atrophy, and Lewy body disease, are characterized by the presence of abundant neuronal inclusions called Lewy bodies and Lewy neurites. These disorders remain incurable, and a greater understanding of the pathologic processes is needed for effective treatment strategies to be developed. Recent data suggest that pathogenic misfolding of the presynaptic protein, α-synuclein (α-syn), and subsequent aggregation and accumulation are fundamental to the disease process. It is hypothesized that the misfolded isoform is able to induce misfolding of normal endogenous α-syn, much like what occurs in the prion diseases. Recent work highlighting the seeding effect of pathogenic α-syn has largely focused on the detergent-insoluble species of the protein. In this study, we performed intracerebral inoculations of the sarkosyl-insoluble or sarkosyl-soluble fractions of human Lewy body disease brain homogenate and show that both fractions induce CNS pathology in mice at 4 months after injection. Disease-associated deposits accumulated both near and distal to the site of the injection, suggesting a cell-to-cell spread via recruitment of α-syn. These results provide further insight into the prion-like mechanisms of α-syn and suggest that disease-associated α-syn is not homogeneous within a single patient but might exist in both soluble and insoluble isoforms.

Topics: Adaptation, Ocular; Age Factors; Aged; alpha-Synuclein; Animals; Brain; Calcium-Binding Proteins; Detergents; Disease Models, Animal; Exploratory Behavior; Female; Glial Fibrillary Acidic Protein; Humans; Lewy Body Disease; Male; Maze Learning; Mice; Mice, Transgenic; Microfilament Proteins; Microscopy, Electron; Muscle Strength; Platelet-Derived Growth Factor; Sarcosine

Tianma Gouteng Yin (TGY) is a traditional Chinese medicine (TCM) decoction widely used to treat symptoms associated with typical Parkinson's disease (PD). In this study, the neuroprotective effects of water extract of TGY were tested on rotenone-intoxicated and human α-synuclein transgenic Drosophila PD models. In addition, the neuroprotective effect of TGY was also evaluated in the human dopaminergic neuroblastoma SH-SY5Y cell line treated with rotenone and the rotenone intoxicated hemi-parkinsonian rats. In rotenone-induced PD models, TGY improved survival rate, alleviated impaired locomotor function of Drosophila, mitigated the loss of dopaminergic neurons in hemi-parkinsonian rats and alleviated apoptotic cell death in SH-SY5Y cells; in α-synuclein transgenic Drosophila, TGY reduced the level of α-synuclein and prevented degeneration of dopaminergic neurons. Conclusively, TGY is neuroprotective in PD models both in vivo and in vitro.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Apoptosis; Cell Count; Cell Line, Tumor; Chromatography, Liquid; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Drosophila; Drug Antagonism; Drugs, Chinese Herbal; Humans; Male; Mass Spectrometry; Medicine, Chinese Traditional; Neuroprotective Agents; Parkinson Disease; Rats; Rotenone

Multiple system atrophy (MSA) is a fatal adult-onset neurodegenerative disease characterized by α-synuclein (α-syn) positive oligodendroglial cytoplasmic inclusions. The latter are associated with a neuronal multisystem neurodegeneration targeting central autonomic, olivopontocerebellar and striatonigral pathways, however the underlying mechanisms of neuronal cell death are poorly understood. Previous experiments have shown that oligodendroglial α-syn pathology increases the susceptibility to mitochondrial stress and proteasomal dysfunction leading to enhanced MSA-like neurodegeneration. Here we analyzed whether oligodendroglial α-syn overexpression in a transgenic mouse model of MSA synergistically interacts with focal neuronal excitotoxic damage generated by a striatal injection of quinolinic acid (QA) to affect the degree of striatal neuronal loss.. QA injury led to comparable striatal neuronal loss and optical density of astro- and microgliosis in the striatum of transgenic and control mice. Respectively, no differences were identified in drug-induced rotation behavior or open field behavior between the groups.. The failure of oligodendroglial α-syn pathology to exacerbate striatal neuronal loss resulting from QA excitotoxicity contrasts with enhanced striatal neurodegeneration due to oxidative or proteolytic stress, suggesting that enhanced vulnerability to excitotoxicity does not occur in oligodendroglial α-synucleinopathy like MSA.

Topics: alpha-Synuclein; Animals; Cell Death; Corpus Striatum; Disease Models, Animal; Gliosis; Humans; Mice, Transgenic; Multiple System Atrophy; Neurons; Oligodendroglia; Quinolinic Acid

The early clinical trials using fetal ventral mesencephalic (VM) allografts in Parkinson's disease (PD) patients have shown efficacy (albeit not in all cases) and have paved the way for further development of cell replacement therapy strategies in PD. The preclinical work that led to these clinical trials used allografts of fetal VM tissue placed into 6-OHDA lesioned rats, while the patients received similar allografts under cover of immunosuppression in an α-synuclein disease state. Thus developing models that more faithfully replicate the clinical scenario would be a useful tool for the translation of such cell-based therapies to the clinic.. Here, we show that while providing functional recovery, transplantation of fetal dopamine neurons into the AAV-α-synuclein rat model of PD resulted in smaller-sized grafts as compared to similar grafts placed into the 6-OHDA-lesioned striatum. Additionally, we found that cyclosporin treatment was able to promote the survival of the transplanted cells in this allografted state and surprisingly also provided therapeutic benefit in sham-operated animals. We demonstrated that delayed cyclosporin treatment afforded neurorestoration in three complementary models of PD including the Thy1-α-synuclein transgenic mouse, a novel AAV-α-synuclein mouse model, and the MPTP mouse model. We then explored the mechanisms for this benefit of cyclosporin and found it was mediated by both cell-autonomous mechanisms and non-cell autonomous mechanisms.. This study provides compelling evidence in favor for the use of immunosuppression in all grafted PD patients receiving cell replacement therapy, regardless of the immunological mismatch between donor and host cells, and also suggests that cyclosporine treatment itself may act as a disease-modifying therapy in all PD patients.

Topics: alpha-Synuclein; Animals; Cell Transplantation; Cells, Cultured; Cognition Disorders; Cyclosporine; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; Enzyme Inhibitors; Female; Humans; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Nerve Tissue Proteins; Neurons; Oxidopamine; Parkinson Disease; Rats; Rats, Sprague-Dawley; Time Factors; Tyrosine 3-Monooxygenase

Deposition of α-synuclein and neuroinflammation are key pathological features of Parkinson's disease (PD). There is no cure for the disease; however, targeting the pathological features might be available to modulate the disease onset and progression. Hypoestoxide (HE) has been demonstrated as a NF-κB modulator, thereby acting as a potential anti-inflammatory and anti-cancer drug.. In order to assess the effect of HE in a mouse model of PD, mThy1-α-syn transgenic mice received intraperitoneal (IP) injections of either vehicle or HE (5 mg/kg) daily for 4 weeks.. Treatment of HE decreased microgliosis, astrogliosis, and pro-inflammatory cytokine gene expression in α-syn transgenic mice. HE administration also prevented the loss of dopaminergic neurons and ameliorated motor behavioral deficits in the α-syn transgenic mice, and α-synuclein pathology was significantly reduced by treatment of HE. In addition, increased levels of nuclear phosphorylated NF-κB in the frontal cortex of α-syn transgenic mice were significantly reduced by HE administration.. These results support the therapeutic potential of HE for PD and other α-synuclein-related diseases.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Diterpenes; Female; Humans; Inflammation; Mice; Mice, Transgenic; Neocortex; NF-kappa B; Parkinson Disease

Cells have developed quality control systems for protection against proteotoxicity. Misfolded and aggregation-prone proteins, which are behind the initiation and progression of many neurodegenerative diseases (ND), are known to challenge the proteostasis network of the cells. We aimed to explore the role of DNJ-27/ERdj5, an endoplasmic reticulum (ER)-resident thioredoxin protein required as a disulfide reductase for the degradation of misfolded proteins, in well-established Caenorhabditis elegans models of Alzheimer, Parkinson and Huntington diseases.. We demonstrate that DNJ-27 is an ER luminal protein and that its expression is induced upon ER stress via IRE-1/XBP-1. When dnj-27 expression is downregulated by RNA interference we find an increase in the aggregation and associated pathological phenotypes (paralysis and motility impairment) caused by human β-amyloid peptide (Aβ), α-synuclein (α-syn) and polyglutamine (polyQ) proteins. In turn, DNJ-27 overexpression ameliorates these deleterious phenotypes. Surprisingly, despite being an ER-resident protein, we show that dnj-27 downregulation alters cytoplasmic protein homeostasis and causes mitochondrial fragmentation. We further demonstrate that DNJ-27 overexpression substantially protects against the mitochondrial fragmentation caused by human Aβ and α-syn peptides in these worm models.. We identify C. elegans dnj-27 as a novel protective gene for the toxicity associated with the expression of human Aβ, α-syn and polyQ proteins, implying a protective role of ERdj5 in Alzheimer, Parkinson and Huntington diseases.. Our data support a scenario where the levels of DNJ-27/ERdj5 in the ER impact cytoplasmic protein homeostasis and the integrity of the mitochondrial network which might underlie its protective effects in models of proteotoxicity associated to human ND.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Autophagy; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Endoplasmic Reticulum-Associated Degradation; Gene Expression; Gene Expression Regulation; HSP40 Heat-Shock Proteins; Humans; Mitochondria; Molecular Chaperones; Neurodegenerative Diseases; Peptides; Phenotype; Proteasome Endopeptidase Complex; Proteolysis; RNA Interference

The GM2 gangliosidoses are progressive neurodegenerative disorders due to defects in the lysosomal β-N-acetylhexosaminidase system. Accumulation of β-hexosaminidases A and B substrates is presumed to cause this fatal condition. An authentic mouse model of Sandhoff disease (SD) with pathological characteristics resembling those noted in infantile GM2 gangliosidosis has been described. We have shown that expression of β-hexosaminidase by intracranial delivery of recombinant adeno-associated viral vectors to young adult SD mice can prevent many features of the disease and extends lifespan. To investigate the nature of the neurological injury in GM2 gangliosidosis and the extent of its reversibility, we have examined the evolution of disease in the SD mouse; we have moreover explored the effects of gene transfer delivered at key times during the course of the illness. Here we report greatly increased survival only when the therapeutic genes are expressed either before the disease is apparent or during its early manifestations. However, irrespective of when treatment was administered, widespread and abundant expression of β-hexosaminidase with consequent clearance of glycoconjugates, α-synuclein and ubiquitinated proteins, and abrogation of inflammatory responses and neuronal loss was observed. We also show that defects in myelination occur in early life and cannot be easily resolved when treatment is given to the adult brain. These results indicate that there is a limited temporal opportunity in which function and survival can be improved-but regardless of resolution of the cardinal pathological features of GM2 gangliosidosis, a point is reached when functional deterioration and death cannot be prevented.

Topics: alpha-Synuclein; Animals; beta-N-Acetylhexosaminidases; Brain; Dependovirus; Disease Models, Animal; G(M2) Ganglioside; Genetic Therapy; Genetic Vectors; Humans; Injections, Intralesional; Mice; Mice, Knockout; Mice, Transgenic; Sandhoff Disease; Tay-Sachs Disease; Ubiquitin

Parkinson's disease (PD) is a neurodegenerative disorder classically characterized by the death of dopamine (DA) neurons in the substantia nigra pars compacta and by intracellular Lewy bodies composed largely of α-synuclein. Approximately 5-10% of PD patients have a familial form of Parkinsonism, including mutations in α-synuclein. To better understand the cell-type specific role of α-synuclein on DA neurotransmission, and the effects of the disease-associated A30P mutation, we generated and studied a novel transgenic model of PD. We expressed the A30P mutant form of human α-synuclein in a spatially-relevant manner from the 111kb SNCA genomic DNA locus on a bacterial artificial chromosome (BAC) insert on a mouse null (Snca-/-) background. The BAC transgenic mice expressed α-synuclein in tyrosine hydroxylase-positive neurons and expression of either A30P α-synuclein or wildtype α-synuclein restored the sensitivity of DA neurons to MPTP in resistant Snca-/- animals. A30P α-synuclein mice showed no Lewy body-like aggregation, and did not lose catecholamine neurons in substantia nigra or locus coeruleus. However, using cyclic voltammetry at carbon-fiber microelectrodes we identified a deficit in evoked DA release in the caudate putamen, but not in the nucleus accumbens, of SNCA-A30P Snca-/- mice but no changes to release of another catecholamine, norepinephrine (NE), in the NE-rich ventral bed nucleus of stria terminalis. SNCA-A30P Snca-/- mice had no overt behavioral impairments but exhibited a mild increase in wheel-running. In summary, this refined PD mouse model shows that A30P α-synuclein preferentially perturbs the dopaminergic system in the dorsal striatum, reflecting the region-specific change seen in PD.

Topics: Age Factors; alpha-Synuclein; Animals; Basal Ganglia; Chromosomes, Artificial, Bacterial; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Norepinephrine; Septal Nuclei

Parkinson's disease (PD) is characterized by the selective degeneration of neuronal populations presumably due to pathogenic interactions between aging and predisposing factors such as increased levels of α-synuclein. Here, we genetically modulate the activity of the transcription factor Forkhead box protein O3 (FOXO3) in adult nigral dopaminergic neurons using viral vectors and explore how this determinant of longevity impacts on neuronal fate in normal and diseased conditions. We find that dopaminergic neurons are particularly vulnerable to changes in FOXO3 activity in the substantia nigra. While constitutive activation has proapoptotic effects leading to neuronal loss, inhibition of FOXO-mediated transcription by a dominant-negative competitor causes oxidative damage and is detrimental at high vector dose. To address the role of FOXO3 in PD, we modulate its activity in dopaminergic neurons overexpressing human α-synuclein. In this pathogenic condition, we find that FOXO inhibition has protective effects, suggesting that this transcription factor ultimately contributes to neuronal cell death. Nevertheless, mild FOXO3 activity also protects nigral neurons against the accumulation of human α-synuclein, albeit to a lesser extent. FOXO3 reduces the amount of α-synuclein present in the soluble protein fraction and promotes the coalescence of dense proteinase K-resistant aggregates, with an accumulation of autophagic vacuoles containing lipofuscin. Consistent with these in vivo observations, we find that FOXO3 controls autophagic flux in neuronal cells. Altogether, these results point to FOXO3 as an important determinant of neuronal survival in the substantia nigra, which may oppose α-synuclein accumulation and proteotoxicity.

Topics: alpha-Synuclein; Animals; Cell Death; Dependovirus; Disease Models, Animal; DNA Damage; Dopaminergic Neurons; Forkhead Box Protein O3; Forkhead Transcription Factors; Gene Expression Regulation; Genetic Vectors; Humans; Oxidation-Reduction; Rats; Substantia Nigra

Parkinson's disease (PD) patients frequently display loss of body fat mass and increased energy expenditure, and several studies have outlined a relationship between these metabolic abnormalities and disease severity, yet energy metabolism is largely unstudied in mouse models of PD. Here we characterize metabolic and physiologic responses to a high calorie diet (HCD) in mice expressing in neurons a mutant form of human α-synuclein (A53T) that causes dominantly inherited familial forms of the disease. A53T (SNCA) and wild type (WT) littermate mice were placed on a HCD for 12 weeks and evaluated for weight gain, food intake, body fat, blood plasma leptin, hunger, glucose tolerance, and energy expenditure. Results were compared with both SNCA and WT mice on a control diet. Despite consuming similar amounts of food, WT mice gained up to 66% of their original body weight on a HCD, whereas SNCA mice gained only 17%. Further, after 12 weeks on a HCD, magnetic resonance imaging analysis revealed that WT mice had significantly greater total and visceral body fat compared with SNCA mice (p < 0.007). At the age of 24 weeks SNCA mice displayed significantly increased hunger compared with WT (p < 0.03). At the age of 36 weeks, SNCA mice displayed significant hypoleptinemia compared with WT, both on a normal diet and a HCD (p < 0.03). The HCD induced insulin insensitivity in WT, but not SNCA mice, as indicated by an oral glucose tolerance test. Finally, SNCA mice displayed greater energy expenditure compared with WT, as measured in a Comprehensive Laboratory Animal Monitoring System, after 12 weeks on a HCD. Thus, SNCA mice are resistant to HCD-induced obesity and insulin resistance and display reduced body fat, increased hunger, hypoleptinemia and increased energy expenditure. Our findings reveal a profile of metabolic dysfunction in a mouse model of PD that is similar to that of human PD patients, thus providing evidence that α-synuclein pathology is sufficient to drive such metabolic abnormalities and providing an animal model for discovery of the underlying mechanisms and potential therapeutic interventions.

Topics: Adipose Tissue; alpha-Synuclein; Animals; Disease Models, Animal; Energy Intake; Energy Metabolism; Insulin Resistance; Leptin; Male; Mice; Mutation; Parkinson Disease

Parkinson's disease (PD) is clinically characterized not only by motor symptoms but also by non-motor symptoms, such as anxiety and mood changes. Based on our previous study showing that overexpression of wild-type or mutant α-synuclein (α-SYN) interferes with cAMP/PKA-dependent transcriptional activation in norepinephrine (NE)-producing cells, the effect of wild-type and mutant α-SYN on cAMP response element (CRE)-mediated regulation of the NE-synthesizing enzyme dopamine β-hydroxylase (DBH) was evaluated in this study. Overexpression of wild-type or mutant α-SYN interfered with CRE-mediated regulation of DBH transcription in NE-producing SK-N-BE(2) cells. Upon entering the nucleus, α-SYN interacted with the DBH promoter region encompassing the CRE, which interfered with forskolin-induced CREB binding to the CRE region. Interestingly, mutant A53T α-SYN showed much higher tendency to nuclear translocation and interaction with the DBH promoter region encompassing the CRE than wild type. In addition, A53T α-SYN expressing transgenic mice exhibited increased anxiety-like behaviors under normal conditions and abnormal regulation of DBH expression in response to immobilization stress with abnormal adaptive responses. These data provide an insight into the physiological function of α-SYN in NErgic neuronal cells, which further indicates that the α-SYN mutation may play a causative role in the generation of non-motor symptoms in PD.

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Colforsin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Dark Adaptation; Disease Models, Animal; Dopamine beta-Hydroxylase; Exploratory Behavior; Female; Humans; Mice; Mice, Transgenic; Mutation; Restraint, Physical; Stress, Physiological; Time Factors; Transfection; Up-Regulation

Parkinson's disease (PD) is a progressive neurodegenerative disorder whose etiology is still unclear in spite of extensive investigations. It has been hypothesized that 5-S-cysteinyldopamine (CysDA), a catechol-thioether metabolite of dopamine (DA), could be an endogenous parkinsonian neurotoxin. To gain further insight into its role in the neurodegenerative process, both CD1 mice and SH-SY5Y neuroblastoma cells were treated with CysDA, and the data were compared with those obtained by the use of 6-hydroxydopamine, a well-known parkinsonian mimetic. Intrastriatal injection of CysDA in CD1 mice caused a long-lasting depletion of DA, providing evidence of in vivo neurotoxicity of CysDA. Both in mice and in SH-SY5Y cells, CysDA treatment induced extensive oxidative stress, as evidenced by protein carbonylation and glutathione depletion, and affected the expression of two proteins, α-synuclein (α-Syn) and ERp57, whose levels are modulated by oxidative insult. Real-time PCR experiments support these findings, indicating an upregulation of both ERp57 and α-Syn expression. α-Syn aggregation was also found to be modulated by CysDA treatment. The present work provides a solid background sustaining the hypothesis that CysDA is involved in parkinsonian neurodegeneration by inducing extensive oxidative stress and protein aggregation.

Topics: alpha-Synuclein; Animals; Biogenic Monoamines; Brain; Cell Line, Tumor; Disease Models, Animal; Dopamine; Dopamine Agents; Dose-Response Relationship, Drug; Glutathione; Glutathione Disulfide; Humans; Male; Mice; Neuroblastoma; Oxidative Stress; Oxidopamine; Parkinson Disease; Protein Carbonylation; Protein Disulfide-Isomerases

Multiple system atrophy (MSA) is a neurodegenerative disease characterized by the pathological accumulation of alpha-synuclein (α-syn) within oligodendroglial cells. This accumulation is accompanied by neuroinflammation with astrogliosis and microgliosis, that leads to neuronal death and subsequent parkinsonism and dysautonomia. Antidepressants have been explored as neuroprotective agents as they normalize neurotrophic factor levels, increase neurogenesis and reduce neurodegeneration, but their anti-inflammatory properties have not been fully characterized. We analyzed the anti-inflammatory profiles of three different antidepressants (fluoxetine, olanzapine and amitriptyline) in the MBP1-hα-syn transgenic (tg) mouse model of MSA. We observed that antidepressant treatment decreased the number of α-syn-positive cells in the basal ganglia of 11-month-old tg animals. This reduction was accompanied with a similar decrease in the colocalization of α-syn with astrocyte markers in this brain structure. Consistent with these results, antidepressants reduced astrogliosis in the hippocampus and basal ganglia of the MBP1-hα-syn tg mice, and modulated the expression levels of key cytokines that were dysregulated in the tg mouse model, such as IL-1β. In vitro experiments in the astroglial cell line C6 confirmed that antidepressants inhibited NF-κB translocation to the nucleus and reduced IL-1β protein levels. We conclude that the anti-inflammatory properties of antidepressants in the MBP1-hα-syn tg mouse model of MSA might be related to their ability to inhibit α-syn propagation from oligodendrocytes to astroglia and to regulate transcription factors involved in cytokine expression. Our results suggest that antidepressants might be of interest as anti-inflammatory and α-syn-reducing agents for MSA and other α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Antidepressive Agents; Astrocytes; Disease Models, Animal; Inflammation; Mice; Mice, Transgenic; Multiple System Atrophy; Neurons; NF-kappa B; Oligodendroglia

Panax ginseng has been used in traditional Chinese medicine for centuries. Among its various benefits is a pluripotent targeting of the various events involved in neuronal cell death. This includes anti-inflammatory, anti-oxidant, and anti-apoptotic effects. Indeed, ginseng extract and its individual ginsenosides have been demonstrated to influence a number of biochemical markers implicated in Parkinson's disease (PD) pathogenesis. We have reported previously that administration of the ginseng extract, G115, afforded robust neuroprotection in two rodent models of PD. However, these traditional rodent models are acute in nature and do accurately recapitulate the progressive nature of the disease. Chronic exposure to the dietary phytosterol glucoside, β-sitosterol β-d-glucoside (BSSG) triggers the progressive development of neurological deficits, with behavioral and cellular features that closely approximate those observed in PD patients. Clinical signs and histopathology continue to develop for several months following cessation of exposure to the neurotoxic insult. Here, we utilized this model to further characterize the neuroprotective effects of the ginseng extract, G115. Oral administration of this extract significantly reduced dopaminergic cell loss, microgliosis, and accumulation of α-synuclein aggregates. Further, G115 administration fully prevented the development of locomotor deficits, in the form of reduced locomotor activity and coordination. These results suggest that ginseng extract may be a potential neuroprotective therapy for the treatment of PD.

Topics: alpha-Synuclein; Animals; Cell Death; Disease Models, Animal; Disease Progression; Drug Evaluation, Preclinical; Encephalitis; Female; Gait Disorders, Neurologic; Neuroprotective Agents; Panax; Parkinson Disease, Secondary; Phytotherapy; Plant Extracts; Rats; Rats, Sprague-Dawley; Sitosterols; Substantia Nigra

Parkinson's disease (PD) is a movement disorder caused by neurodegeneration in neocortex, substantia nigra and brainstem, and synucleinopathy. Some inherited PD is caused by mutations in α-synuclein (αSyn), and inherited and idiopathic PD is associated with mitochondrial perturbations. However, the mechanisms of pathogenesis are unresolved. We characterized a human αSyn transgenic mouse model and tested the hypothesis that the mitochondrial permeability transition pore (mPTP) is involved in the disease mechanisms. C57BL/6 mice expressing human A53T-mutant αSyn driven by a thymic antigen-1 promoter develop a severe, age-related, fatal movement disorder involving ataxia, rigidity, and postural instability. These mice develop synucleinopathy and neocortical, substantia nigra, and cerebello-rubro-thalamic degeneration involving mitochondriopathy and apoptotic and non-apoptotic neurodegeneration. Interneurons undergo apoptotic degeneration in young mice. Mutant αSyn associated with dysmorphic neuronal mitochondria and bound voltage-dependent anion channels. Genetic ablation of cyclophilin D, an mPTP modulator, delayed disease onset, and extended lifespans of mutant αSyn mice. Thus, mutant αSyn transgenic mice on a C57BL/6 background develop PD-like phenotypes, and the mPTP is involved in their disease mechanisms.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mutation; Parkinson Disease

Parkinson's disease (PD) is a neurodegenerative disease affecting up to 80% of dopaminergic neurons in the nigrostriatal pathway. FLZ, a novel synthetic squamosamide derivative from a Chinese herb, has been shown to have neuroprotective effects in experimental PD models. In this study, we carried out a set of in vitro and in vivo experiments to address the neuroprotective effect of FLZ and related mechanism. The results showed that FLZ significantly improved motor dysfunction and dopaminergic neuronal loss of rats injured by 6-hydroxydopamine (6-OHDA). The beneficial effects of FLZ attributed to the elevation of dopaminergic neuron number, dopamine level and tyrosine hydroxylase (TH) activity. Mechanistic study showed that FLZ protected TH activity and dopaminergic neurons through decreasing α-synuclein (α-Syn) expression and the interaction between α-Syn and TH. Further studies indicated the involvement of phosphoinositide 3-kinases (PI3K)/Akt signaling pathway in the protective effect of FLZ since it showed that blocking PI3K/Akt signaling pathway prevented the expression of α-Syn and attenuated the neuroprotection of FLZ. In addition, FLZ treatment reduced the expression of RTP801, an important protein involved in the pathogenesis of PD. Taken together, these results revealed that FLZ suppressed α-Syn expression and elevated TH activity in dopaminergic neuron through activating Akt survival pathway in 6-OHDA-induced PD models. The data also provided evidence that FLZ had potent neuroprotecive effects and might become a new promising agent for PD treatment.

Topics: alpha-Synuclein; Animals; Apomorphine; Benzeneacetamides; Cell Death; Disease Models, Animal; Dopamine Agonists; Dopaminergic Neurons; Male; Motor Activity; Neuroprotective Agents; Oxidopamine; Parkinson Disease; Phenols; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Repressor Proteins; Signal Transduction; Transcription Factors; Tyrosine 3-Monooxygenase

Clinical, epidemiological and experimental studies confirm a connection between the common degenerative movement disorder Parkinson's disease (PD) that affects over 1 million individuals, and Gaucher disease, the most prevalent lysosomal storage disorder. Recently, human imaging studies have implicated impaired striatal dopaminergic neurotransmission in early PD pathogenesis in the context of Gaucher disease mutations, but the underlying mechanisms have yet to be characterized. In this report we describe and characterize two novel long-lived transgenic mouse models of Gba deficiency, along with a subchronic conduritol-ß-epoxide (CBE) exposure paradigm. All three murine models revealed striking glial activation within nigrostriatal pathways, accompanied by abnormal α-synuclein accumulation. Importantly, the CBE-induced, pharmacological Gaucher mouse model replicated this change in dopamine neurotransmission, revealing a markedly reduced evoked striatal dopamine release (approximately 2-fold) that indicates synaptic dysfunction. Other changes in synaptic plasticity markers, including microRNA profile and a 24.9% reduction in post-synaptic density size, were concomitant with diminished evoked dopamine release following CBE exposure. These studies afford new insights into the mechanisms underlying the Parkinson's-Gaucher disease connection, and into the physiological impact of related abnormal α-synuclein accumulation and neuroinflammation on nigrostriatal dopaminergic neurotransmission.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Evoked Potentials, Motor; Female; Gaucher Disease; Glucosylceramidase; Humans; Inflammation; Inositol; Male; Mice; MicroRNAs; Mutation; Neuronal Plasticity; Parkinson Disease; Synapses; Synaptic Transmission

Multiple system atrophy is an intractable neurodegenerative disease caused by α-synuclein (α-syn) accumulation in oligodendrocytes and neurons. With the use of a transgenic mouse model overexpressing human α-syn in oligodendrocytes, we demonstrated that oligodendrocytic α-syn inclusions induce neuronal α-syn accumulation, resulting in progressive neuronal degeneration. The mechanism through which oligodendrocytic α-syn inclusions trigger neuronal α-syn accumulation leading to multiple system atrophy is unknown. In this study, we identified cystatin C, an oligodendrocyte-derived secretory protein that triggers α-syn up-regulation and insoluble α-syn accumulation, in neurons of the mouse central nervous system. Cystatin C was released by mouse oligodendrocytes overexpressing human α-syn, and extracellular cystatin C increased the expression of the endogenous α-syn gene in wild-type mouse neurons. These neurons then accumulate insoluble α-syn and may undergo apoptosis. Cystatin C is a potential pathogenic signal triggering neurodegeneration in multiple system atrophy.

Topics: alpha-Synuclein; Animals; Brain; Cystatin C; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Multiple System Atrophy; Neurons; Oligodendroglia; Up-Regulation

Demyelination is a major contributor to the general decay of neural functions in children with Krabbe disease. However, recent reports have indicated a significant involvement of neurons and axons in the neuropathology of the disease. In this study, we have investigated the nature of cellular inclusions in the Krabbe brain. Brain samples from the twitcher mouse model for Krabbe disease and from patients affected with the infantile and late-onset forms of the disease were examined for the presence of neuronal inclusions. Our experiments demonstrated the presence of cytoplasmic aggregates of thioflavin-S-reactive material in both human and murine mutant brains. Most of these inclusions were associated with neurons. A few inclusions were detected to be associated with microglia and none were associated with astrocytes or oligodendrocytes. Thioflavin-S-reactive inclusions increased in abundance, paralleling the development of neurological symptoms, and distributed throughout the twitcher brain in areas of major involvement in cognition and motor functions. Electron microscopy confirmed the presence of aggregates of stereotypic β-sheet folded proteinaceous material. Immunochemical analyses identified the presence of aggregated forms of α-synuclein and ubiquitin, proteins involved in the formation of Lewy bodies in Parkinson's disease and other neurodegenerative conditions. In vitro assays demonstrated that psychosine, the neurotoxic sphingolipid accumulated in Krabbe disease, accelerated the fibrillization of α-synuclein. This study demonstrates the occurrence of neuronal deposits of fibrillized proteins including α-synuclein, identifying Krabbe disease as a new α-synucleinopathy.

Topics: alpha-Synuclein; Animals; Benzothiazoles; Brain; Case-Control Studies; Cognition; Disease Models, Animal; Fluorescent Dyes; Humans; Leukodystrophy, Globoid Cell; Lewy Bodies; Mice; Motor Activity; Mutation; Neurons; Psychosine; Thiazoles

Parkinson's disease (PD) is the second most common degenerative disorder of the central nervous system that impairs motor skills and cognitive function. To date, the disease has no effective therapies. The identification of new drugs that provide benefit in arresting the decline seen in PD patients is the focus of much recent study. However, the lengthy time frame for the progression of neurodegeneration in PD increases both the time and cost of examining potential therapeutic compounds in mammalian models. An alternative is to first evaluate the efficacy of compounds in Caenorhabditis elegans models, which reduces examination time from months to days. n-Butylidenephthalide is the naturally-occurring component derived from the chloroform extract of Angelica sinensis. It has been shown to have anti-tumor and anti-inflammatory properties, but no reports have yet described the effects of n-butylidenephthalide on PD. The aim of this study was to assess the potential for n-butylidenephthalide to improve PD in C. elegans models.. In the current study, we employed a pharmacological strain that expresses green fluorescent protein specifically in dopaminergic neurons (BZ555) and a transgenic strain that expresses human α-synuclein in muscle cells (OW13) to investigate the antiparkinsonian activities of n-butylidenephthalide. Our results demonstrate that in PD animal models, n-butylidenephthalide significantly attenuates dopaminergic neuron degeneration induced by 6-hydroxydopamine; reduces α-synuclein accumulation; recovers lipid content, food-sensing behavior, and dopamine levels; and prolongs life-span of 6-hydroxydopamine treatment, thus revealing its potential as a possible antiparkinsonian drug. n-Butylidenephthalide may exert its effects by blocking egl-1 expression to inhibit apoptosis pathways and by raising rpn-6 expression to enhance the activity of proteasomes.. n-Butylidenephthalide may be one of the effective neuroprotective agents for PD.

Topics: alpha-Synuclein; Angelica sinensis; Animals; Antiparkinson Agents; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Drugs, Chinese Herbal; Gene Expression Regulation; Humans; Longevity; Muscle Cells; Oxidopamine; Parkinson Disease; Phthalic Anhydrides; Proteasome Endopeptidase Complex; Repressor Proteins; Transgenes

Clinical and pathological studies have suggested considerable overlap between tauopathies and synucleinopathies. Several genome-wide association studies have identified alpha-Synuclein (SNCA) and Tau (MAPT) polymorphisms as common risk factors for sporadic Parkinson's disease (PD). However, the mechanisms by which subtle variations in the expression of wild-type SNCA and MAPT influence risk for PD and the underlying cellular events that effect neurotoxicity remain unclear. To examine causes of neurotoxicity associated with the α-Syn/Tau interaction, we used the fruit fly as a model. We utilized misexpression paradigms in three different tissues to probe the α-Syn/Tau interaction: the retina, dopaminergic neurons and the larval neuromuscular junction. Misexpression of Tau and α-Syn enhanced a rough eye phenotype and loss of dopaminergic neurons in fly tauopathy and synucleinopathy models, respectively. Our findings suggest that interactions between α-Syn and Tau at the cellular level cause disruption of cytoskeletal organization, axonal transport defects and aberrant synaptic organization that contribute to neuronal dysfunction and death associated with sporadic PD. α-Syn did not alter levels of Tau phosphorylated at the AT8 epitope. However, α-Syn and Tau colocalized in ubiquitin-positive aggregates in eye imaginal discs. The presence of Tau also led to an increase in urea soluble α-Syn. Our findings have important implications in understanding the cellular and molecular mechanisms underlying α-Syn/Tau-mediated synaptic dysfunction, which likely arise in the early asymptomatic phase of sporadic PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Apoptosis; Cytoskeleton; Disease Models, Animal; Drosophila; Humans; Neurons; Parkinson Disease; Protein Binding; tau Proteins

There are no therapies that reverse the proteotoxic misfolding events that underpin fatal neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Hsp104, a conserved hexameric AAA+ protein from yeast, solubilizes disordered aggregates and amyloid but has no metazoan homolog and only limited activity against human neurodegenerative disease proteins. Here, we reprogram Hsp104 to rescue TDP-43, FUS, and α-synuclein proteotoxicity by mutating single residues in helix 1, 2, or 3 of the middle domain or the small domain of nucleotide-binding domain 1. Potentiated Hsp104 variants enhance aggregate dissolution, restore proper protein localization, suppress proteotoxicity, and in a C. elegans PD model attenuate dopaminergic neurodegeneration. Potentiating mutations reconfigure how Hsp104 subunits collaborate, desensitize Hsp104 to inhibition, obviate any requirement for Hsp70, and enhance ATPase, translocation, and unfoldase activity. Our work establishes that disease-associated aggregates and amyloid are tractable targets and that enhanced disaggregases can restore proteostasis and mitigate neurodegeneration.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Disease Models, Animal; DNA-Binding Proteins; Heat-Shock Proteins; Humans; Models, Molecular; Mutagenesis; Neurons; Parkinson Disease; Protein Folding; Protein Structure, Tertiary; Proteostasis Deficiencies; RNA-Binding Protein FUS; Saccharomyces cerevisiae Proteins

Parkinson's disease (PD) is a neurodegenerative brain disorder characterized by selective dopaminergic (DAergic) cell loss that results in overt motor and cognitive deficits. Current treatment options exist to combat PD symptomatology, but are unable to directly target its pathogenesis due to a lack of knowledge concerning its etiology. Several genes have been linked to PD, including three genes associated with an early-onset familial form: parkin, pink1 and dj1. All three genes are implicated in regulating oxidative stress pathways. Another hallmark of PD pathophysiology is Lewy body deposition, associated with the gain-of-function genetic risk factor α-synuclein. The function of α-synuclein is poorly understood, as it shows both neurotoxic and neuroprotective activities in PD. Using the genetically tractable invertebrate Caenorhabditis elegans (C. elegans) model system, the neurotoxic or neuroprotective role of α-synuclein upon acute Mn exposure in the background of mutated pdr1, pink1 or djr1.1 was examined. The pdr1 and djr1.1 mutants showed enhanced Mn accumulation and oxidative stress that was reduced by α-synuclein. Moreover, DAergic neurodegeneration, while unchanged with Mn exposure, returned to wild-type (WT) levels for pdr1, but not djr1.1 mutants expressing α-synuclein. Taken together, this study uncovers a novel, neuroprotective role for WT human α-synuclein in attenuating Mn-induced toxicity in the background of PD-associated genes, and further supports the role of extracellular dopamine in exacerbating Mn neurotoxicity.

Topics: Aldehyde Oxidoreductases; alpha-Synuclein; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Gene Deletion; Gene Expression Regulation; Humans; Manganese; Mutation; Oxidative Stress; Parkinson Disease; Protein Serine-Threonine Kinases; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is a neurodegenerative disorder in which both alpha-synuclein (α-syn) and dopamine (DA) have a critical role. Our previous studies instigated a novel PD model based on nasal inoculation with α-syn aggregates which expressed parkinsonian-like behavioral and immunological features. The current study in mice substantiated the robustness of the amyloid nasal vector model by examining behavioral consequences with respect to DA-ergic neurochemical corollaries. In vitro generated α-syn oligomers and fibrils were characterized using atomic force microscopy and the thioflavin T binding assay. These toxic oligomers or fibrils administered alone (0.48 mg/kg) or their 50:50 combination (total dose of 0.48 mg/kg) were given intranasally for 14 days and "open-field" behavior was tested on days 0, 15 and 28 of the protocol. Behavioral deficits at the end of the 14-day dosing regime and on day 28 (i.e., 14 days after treatment completion) induced rigidity, hypokinesia and immobility. This was accompanied by elevated nigral but not striatal DA, DOPAC and HVA concentrations in response to dual administration of α-syn oligomers plus fibrils but not the oligomers by themselves. α-Syn fibrils intensified not only the hypokinesia and immobility 14 days post treatment, but also reduced vertical rearing and enhanced DA levels in the substantia nigra. Only nigral DA turnover (DOPAC/DA but not HVA/DA ratio) was augmented in response to fibril treatment but there were no changes in the striatum. Compilation of these novel behavioral and neurochemical findings substantiate the validity of the α-syn nasal vector model for investigating parkinsonian-like symptoms.

Topics: 3,4-Dihydroxyphenylacetic Acid; Administration, Intranasal; alpha-Synuclein; Amyloid; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Homovanillic Acid; Hypokinesia; Male; Mice; Mice, Inbred C57BL; Motor Activity; Muscle Rigidity; Parkinsonian Disorders; Protein Aggregates; Substantia Nigra

Parkinson's disease and dementia with Lewy bodies are associated with abnormal neuronal aggregation of α-synuclein. However, the mechanisms of aggregation and their relationship to disease are poorly understood. We developed an in vivo multiphoton imaging paradigm to study α-synuclein aggregation in mouse cortex with subcellular resolution. We used a green fluorescent protein-tagged human α-synuclein mouse line that has moderate overexpression levels mimicking human disease. Fluorescence recovery after photobleaching (FRAP) of labeled protein demonstrated that somatic α-synuclein existed primarily in an unbound, soluble pool. In contrast, α-synuclein in presynaptic terminals was in at least three different pools: (1) as unbound, soluble protein; (2) bound to presynaptic vesicles; and (3) as microaggregates. Serial imaging of microaggregates over 1 week demonstrated a heterogeneous population with differing α-synuclein exchange rates. The microaggregate species were resistant to proteinase K, phosphorylated at serine-129, oxidized, and associated with a decrease in the presynaptic vesicle protein synapsin and glutamate immunogold labeling. Multiphoton FRAP provided the specific binding constants for α-synuclein's binding to synaptic vesicles and its effective diffusion coefficient in the soma and axon, setting the stage for future studies targeting synuclein modifications and their effects. Our in vivo results suggest that, under moderate overexpression conditions, α-synuclein aggregates are selectively found in presynaptic terminals.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Fluorescence Recovery After Photobleaching; Humans; Male; Mice; Mice, Transgenic; Parkinson Disease; Presynaptic Terminals

The olfactory bulb (OB) is one of the first brain regions in Parkinson's disease (PD) to contain alpha-synuclein (α-syn) inclusions, possibly associated with nonmotor symptoms. Mechanisms underlying olfactory synucleinopathy, its contribution to progressive aggregation pathology and nigrostriatal dopaminergic loss observed at later stages, remain unclear. A second hit, such as environmental toxins, is suggestive for α-syn aggregation in olfactory neurons, potentially triggering disease progression. To address the possible pathogenic role of olfactory α-syn accumulation in early PD, we exposed mice with site-specific and inducible overexpression of familial PD-linked mutant α-syn in OB neurons to a low dose of the herbicide paraquat. Here, we found that olfactory α-syn per se elicited structural and behavioral abnormalities, characteristic of an early time point in models with widespread α-syn expression, including hyperactivity and increased striatal dopaminergic marker. Suppression of α-syn reversed the dopaminergic phenotype. In contrast, paraquat treatment synergistically induced degeneration of olfactory dopaminergic cells and opposed the higher reactive phenotype. Neither neurodegeneration nor behavioral abnormalities were detected in paraquat-treated mice with suppressed α-syn expression. By increasing calpain activity, paraquat induced a pathological cascade leading to inhibition of autophagy clearance and accumulation of calpain-cleaved truncated and insoluble α-syn, recapitulating biochemical and structural changes in human PD. Thus our results underscore the primary role of proteolytic failure in aggregation pathology. In addition, we provide novel evidence that olfactory dopaminergic neurons display an increased vulnerability toward neurotoxins in dependence to presence of human α-syn, possibly mediating an olfactory-striatal dopaminergic network dysfunction in mouse models and early PD.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Animals; Autophagy; Cell Line, Tumor; Corpus Striatum; Disease Models, Animal; Dopaminergic Neurons; Female; Gene Expression Regulation; Humans; Male; Mice; Mice, Transgenic; Mutation; Neural Pathways; Neurotoxins; Olfactory Bulb; Paraquat

Immunotherapeutic approaches are currently in the spotlight for their potential as disease-modifying treatments for neurodegenerative disorders. The discovery that α-synuclein (α-syn) can transmit from cell to cell in a prion-like fashion suggests that immunization might be a viable option for the treatment of synucleinopathies. This possibility has been bolstered by the development of next-generation active vaccination technology with short peptides-AFFITOPEs(®) (AFF)- that do not elicit an α-syn-specific T cell response. This approach allows for the production of long term, sustained, more specific, non-cross reacting antibodies suitable for the treatment of synucleinopathies, such as Parkinson's disease (PD). In this context, we screened a large library of peptides that mimic the C-terminus region of α-syn and discovered a novel set of AFF that identified α-syn oligomers. Next, the peptide that elicited the most specific response against α-syn (AFF 1) was selected for immunizing two different transgenic (tg) mouse models of PD and Dementia with Lewy bodies, the PDGF- and the mThy1-α-syn tg mice. Vaccination with AFF 1 resulted in high antibody titers in CSF and plasma, which crossed into the CNS and recognized α-syn aggregates. Active vaccination with AFF 1 resulted in decreased accumulation of α-syn oligomers in axons and synapses, accompanied by reduced degeneration of TH fibers in the caudo-putamen nucleus and by improvements in motor and memory deficits in both in vivo models. Clearance of α-syn involved activation of microglia and increased anti-inflammatory cytokine expression, further supporting the efficacy of this novel active vaccination approach for synucleinopathies.

Topics: alpha-Synuclein; Animals; Antibodies; Axons; Caudate Nucleus; Clinical Trials as Topic; Disease Models, Animal; Humans; Lewy Body Disease; Memory Disorders; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Motor Activity; Nerve Degeneration; Parkinson Disease; Putamen; Synapses; T-Lymphocytes; Vaccination

Mutations in the gene for alpha-galactosidase A result in Fabry disease, a rare, X-linked lysosomal storage disorder characterized by a loss of alpha-galactosidase A enzymatic activity. The resultant accumulation of glycosphingolipids throughout the body leads to widespread vasculopathy with particular detriment to the kidneys, heart and nervous system. Disruption in the autophagy-lysosome pathway has been documented previously in Fabry disease but its relative contribution to nervous system pathology in Fabry disease is unknown. Using an experimental mouse model of Fabry disease, alpha-galactosidase A deficiency, we examined brain pathology in 20-24 month old mice with particular emphasis on the autophagy-lysosome pathway.. Alpha-galactosidase A-deficient mouse brains exhibited enhanced punctate perinuclear immunoreactivity for the autophagy marker microtubule-associated protein light-chain 3 (LC3) in the parenchyma of several brain regions, as well as enhanced parenchymal and vascular immunoreactivity for lysosome-associated membrane protein-1 (LAMP-1). Ultrastructural analysis revealed endothelial cell inclusions with electron densities and a pronounced accumulation of electron-dense lipopigment. The pons of alpha-galactosidase A-deficient mice in particular exhibited a striking neuropathological phenotype, including the presence of large, swollen axonal spheroids indicating axonal degeneration, in addition to large interstitial aggregates positive for phosphorylated alpha-synuclein that co-localized with the axonal spheroids. Double-label immunofluorescence revealed co-localization of phosphorylated alpha-synuclein aggregates with ubiquitin and LC3.. Together these findings indicate widespread neuropathology and focused axonal neurodegeneration in alpha-galactosidase A-deficient mouse brain in association with disruption of the autophagy-lysosome pathway, and provide the basis for future mechanistic assessment of the contribution of the autophagy-lysosome pathway to this histologic phenotype.

Topics: alpha-Galactosidase; alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Fabry Disease; Gene Expression Regulation; Inclusion Bodies; Lysosomal Membrane Proteins; Lysosomes; Mice; Mice, Knockout; Microscopy, Electron; Microtubule-Associated Proteins; Nerve Degeneration; Optical Imaging; Signal Transduction

The anti-epileptic agent zonisamide (ZNS) has been shown to exert protective effects in neurotoxin-based mouse models of Parkinson disease. However, it is unknown whether ZNS can attenuate toxicity of familial Parkinson's disease-causing gene products. In this study, we investigated the effects of ZNS on neurodegeneration induced by expression of A53T α-synuclein in the rat substantia nigra using a recombinant adeno-associated virus vector. Expression of A53T α-synuclein yielded severe loss of nigral dopamine neurons and striatal dopamine nerve terminals from 2 weeks to 4 weeks after viral injection. Oral administration of ZNS (40 mg/kg/day) significantly delayed the pace of degeneration at 4 weeks after viral injection as compared with the vehicle group. This effect lasted until 8 weeks after viral injection, the final point of observation. ZNS treatment had no impact on the survival of nigrostriatal dopamine neurons in rats expressing green fluorescent protein. Quantification of striatal Ser129-phosphorylated α-synuclein-positive aggregates showed that these aggregates rapidly formed from 2 weeks to 4 weeks after viral injection. This increase was closely correlated with loss of nigrostriatal dopamine neurons. However, ZNS treatment failed to alter the number of all striatal Ser129-phosphorylated α-synuclein-positive aggregates, including small dot-like and large round structures. The number of these aggregates was almost constant at 4 weeks and 8 weeks after viral injection, although ZNS persistently prevented loss of nigrostriatal dopamine neurons during this period. Also, ZNS treatment did not affect the number of striatal aggregates larger than 10 µm in diameter. These data show that ZNS attenuates α-synuclein-induced toxicity in a manner that is independent of the formation and maturation of α-synuclein aggregates in an in vivo model of familial Parkinson's disease, suggesting that ZNS may protect nigrostriatal dopamine neurons by modulating cellular damage or a cell death pathway commonly caused by neurotoxins and α-synuclein.

Topics: alpha-Synuclein; Animals; Cell Count; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Isoxazoles; Male; Mice; Neuroprotective Agents; Parkinson Disease; Protein Aggregation, Pathological; Rats; Substantia Nigra; Time Factors; Zonisamide

Gaucher disease, a prevalent lysosomal storage disease (LSD), is caused by insufficient activity of acid β-glucosidase (GCase) and the resultant glucosylceramide (GC)/glucosylsphingosine (GS) accumulation in visceral organs (Type 1) and the central nervous system (Types 2 and 3). Recent clinical and genetic studies implicate a pathogenic link between Gaucher and neurodegenerative diseases. The aggregation and inclusion bodies of α-synuclein with ubiquitin are present in the brains of Gaucher disease patients and mouse models. Indirect evidence of β-amyloid pathology promoting α-synuclein fibrillation supports these pathogenic proteins as a common feature in neurodegenerative diseases. Here, multiple proteins are implicated in the pathogenesis of chronic neuronopathic Gaucher disease (nGD). Immunohistochemical and biochemical analyses showed significant amounts of β-amyloid and amyloid precursor protein (APP) aggregates in the cortex, hippocampus, stratum and substantia nigra of the nGD mice. APP aggregates were in neuronal cells and colocalized with α-synuclein signals. A majority of APP co-localized with the mitochondrial markers TOM40 and Cox IV; a small portion co-localized with the autophagy proteins, P62/LC3, and the lysosomal marker, LAMP1. In cultured wild-type brain cortical neural cells, the GCase-irreversible inhibitor, conduritol B epoxide (CBE), reproduced the APP/α-synuclein aggregation and the accumulation of GC/GS. Ultrastructural studies showed numerous larger-sized and electron-dense mitochondria in nGD cerebral cortical neural cells. Significant reductions of mitochondrial adenosine triphosphate production and oxygen consumption (28-40%) were detected in nGD brains and in CBE-treated neural cells. These studies implicate defective GCase function and GC/GS accumulation as risk factors for mitochondrial dysfunction and the multi-proteinopathies (α-synuclein-, APP- and Aβ-aggregates) in nGD.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; beta-Glucosidase; Cells, Cultured; Cerebral Cortex; Corpus Striatum; Disease Models, Animal; Enzyme Inhibitors; Gaucher Disease; Gene Expression Regulation; Hippocampus; Humans; Inositol; Lysosomal Membrane Proteins; Membrane Transport Proteins; Mice; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Proteins; Neurons; Prostaglandin-Endoperoxide Synthases; Protein Aggregation, Pathological; Substantia Nigra

Lewy bodies, a pathological hallmark of Parkinson's disease (PD), contain aggregated alpha-synuclein (αSyn), which is found in several modified forms and can be discovered phosphorylated, ubiquitinated and truncated. Aggregation-prone truncated species of αSyn caused by aberrant cleavage of this fibrillogenic protein are hypothesized to participate in its sequestration into inclusions subsequently leading to synaptic dysfunction and neuronal death. Here, we investigated the role of calpain cleavage of αSyn in vivo by generating two opposing mouse models. We crossed into human [A30P]αSyn transgenic (i) mice deficient for calpastatin, a calpain-specific inhibitor, thus enhancing calpain activity (SynCAST(-)) and (ii) mice overexpressing human calpastatin leading to reduced calpain activity (SynCAST(+)). As anticipated, a reduced calpain activity led to a decreased number of αSyn-positive aggregates, whereas loss of calpastatin led to increased truncation of αSyn in SynCAST(-). Furthermore, overexpression of calpastatin decreased astrogliosis and the calpain-dependent degradation of synaptic proteins, potentially ameliorating the observed neuropathology in [A30P]αSyn and SynCAST(+) mice. Overall, our data further support a crucial role of calpains, particularly of calpain 1, in the pathogenesis of PD and in disease-associated aggregation of αSyn, indicating a therapeutic potential of calpain inhibition in PD.

Topics: alpha-Synuclein; Animals; Calcium-Binding Proteins; Calpain; Disease Models, Animal; Gene Expression Regulation; Humans; Lewy Bodies; Mice; Mice, Transgenic; Neurons; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; Proteolysis; Signal Transduction; Synapses

The accumulation of misfolded proteins appears as a fundamental pathogenic process in human neurodegenerative diseases. In the case of synucleinopathies such as Parkinson's disease (PD) or dementia with Lewy bodies (DLB), the intraneuronal deposition of aggregated alpha-synuclein (αS) is a major characteristic of the disease, but the molecular basis distinguishing the disease-associated protein (αSD) from its normal counterpart remains poorly understood. However, recent research suggests that a prion-like mechanism could be involved in the inter-cellular and inter-molecular propagation of aggregation of the protein within the nervous system.. Our data confirm our previous observations of disease acceleration in a transgenic mouse line (M83) overexpressing a mutated (A53T) form of human αS, following inoculation of either brain extracts from sick M83 mice or fibrillar recombinant αS. A similar phenomenon is observed following a "second passage" in the M83 mouse model, including after stereotactic inoculations into the hippocampus or cerebellum. For further molecular analyses of αSD, we designed an ELISA test that identifies αSD specifically in sick mice and in the brain regions targeted by the pathological process in this mouse model. αSD distribution, mainly in the caudal brain regions and spinal cord, overall appears remarkably uniform, whatever the conditions of experimental challenge. In addition to specific detection of αSD immunoreactivity using an antibody against Ser129 phosphorylated αS, similar results were observed in ELISA with several other antibodies against the C-terminal part of αS, including an antibody against non phosphorylated αS. This also indicated consistent immunoreactivity of the murine αS protein specifically in the affected brain regions of sick mice.. Prion-like behaviour in propagation of the disease-associated αS was confirmed with the M83 transgenic mouse model, that could be followed by an ELISA test. The ELISA data question their possible relationship with the conformational differences between the disease-associated αS and its normal counterpart.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Humans; Lewy Body Disease; Mice; Mice, Transgenic; Mutation; Neurons

α-synuclein (aSyn) expression is implicated in neurodegenerative processes, including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In animal models of these diseases, axon pathology often precedes cell death, raising the question of whether aSyn has compartment-specific toxic effects that could require early and/or independent therapeutic intervention. The relevance of axonal pathology to degeneration can only be addressed through longitudinal, in vivo monitoring of different neuronal compartments. With current imaging methods, dopaminergic neurons do not readily lend themselves to such a task in any vertebrate system. We therefore expressed human wild-type aSyn in zebrafish peripheral sensory neurons, which project elaborate superficial axons that can be continuously imaged in vivo. Axonal outgrowth was normal in these neurons but, by 2 days post-fertilization (dpf), many aSyn-expressing axons became dystrophic, with focal varicosities or diffuse beading. Approximately 20% of aSyn-expressing cells died by 3 dpf. Time-lapse imaging revealed that focal axonal swelling, but not overt fragmentation, usually preceded cell death. Co-expressing aSyn with a mitochondrial reporter revealed deficits in mitochondrial transport and morphology even when axons appeared overtly normal. The axon-protective protein Wallerian degeneration slow (WldS) delayed axon degeneration but not cell death caused by aSyn. By contrast, the transcriptional coactivator PGC-1α, which has roles in the regulation of mitochondrial biogenesis and reactive-oxygen-species detoxification, abrogated aSyn toxicity in both the axon and the cell body. The rapid onset of axonal pathology in this system, and the relatively moderate degree of cell death, provide a new model for the study of aSyn toxicity and protection. Moreover, the accessibility of peripheral sensory axons will allow effects of aSyn to be studied in different neuronal compartments and might have utility in screening for novel disease-modifying compounds.

Topics: alpha-Synuclein; Animals; Axons; Cell Death; Disease Models, Animal; Fertilization; Humans; Larva; Mitochondria; Nerve Degeneration; Protein Transport; Sensory Receptor Cells; Transcription Factors; Wallerian Degeneration; Zebrafish; Zebrafish Proteins

Autophagy is a major degradation pathway for abnormal aggregated proteins and organelles that cause various neurodegenerative diseases. Current evidence suggests a central role for autophagy in pathogenesis of Parkinson's disease, and that dysfunction in the autophagic system may lead to α-synuclein accumulation. In the present study, we investigated whether mesenchymal stem cells (MSCs) would enhance autophagy and thus exert a neuroprotective effect through the modulation of α-synuclein in parkinsonian models. In MPP(+)-treated neuronal cells, coculture with MSCs increased cellular viability, attenuated expression of α-synuclein, and enhanced the number of LC3-II-positive autophagosomes compared with cells treated with MPP(+) only. In an MPTP-treated animal model of Parkinson's disease, MSC administration significantly increased final maturation of late autophagic vacuoles, fusion with lysosomes. Moreover, MSC administration significantly reduced the level of α-synuclein in dopaminergic neurons, which was elevated in MPTP-treated mice. These results suggest that MSC treatment significantly enhances autophagolysosome formation and may modulate α-synuclein expression in parkinsonian models, which may lead to increased neuronal survival in the presence of neurotoxins.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Autophagy; Cell Survival; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Mesenchymal Stem Cells; Mice, Inbred C57BL; Neurotoxins; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological

In Parkinson's disease and dementia with Lewy bodies, α-synuclein aggregates to form oligomers and fibrils; however, the precise nature of the toxic α-synuclein species remains unclear. A number of synthetic α-synuclein mutations were recently created (E57K and E35K) that produce species of α-synuclein that preferentially form oligomers and increase α-synuclein-mediated toxicity. We have shown that acute lentiviral expression of α-synuclein E57K leads to the degeneration of dopaminergic neurons; however, the effects of chronic expression of oligomer-prone α-synuclein in synapses throughout the brain have not been investigated. Such a study could provide insight into the possible mechanism(s) through which accumulation of α-synuclein oligomers in the synapse leads to neurodegeneration. For this purpose, we compared the patterns of neurodegeneration and synaptic damage between a newly generated mThy-1 α-synuclein E57K transgenic mouse model that is prone to forming oligomers and the mThy-1 α-synuclein wild-type mouse model (Line 61), which accumulates various forms of α-synuclein. Three lines of α-synuclein E57K (Lines 9, 16 and 54) were generated and compared with the wild-type. The α-synuclein E57K Lines 9 and 16 were higher expressings of α-synuclein, similar to α-synuclein wild-type Line 61, and Line 54 was a low expressing of α-synuclein compared to Line 61. By immunoblot analysis, the higher-expressing α-synuclein E57K transgenic mice showed abundant oligomeric, but not fibrillar, α-synuclein whereas lower-expressing mice accumulated monomeric α-synuclein. Monomers, oligomers, and fibrils were present in α-synuclein wild-type Line 61. Immunohistochemical and ultrastructural analyses demonstrated that α-synuclein accumulated in the synapses but not in the neuronal cells bodies, which was different from the α-synuclein wild-type Line 61, which accumulates α-synuclein in the soma. Compared to non-transgenic and lower-expressing mice, the higher-expressing α-synuclein E57K mice displayed synaptic and dendritic loss, reduced levels of synapsin 1 and synaptic vesicles, and behavioural deficits. Similar alterations, but to a lesser extent, were seen in the α-synuclein wild-type mice. Moreover, although the oligomer-prone α-synuclein mice displayed neurodegeneration in the frontal cortex and hippocampus, the α-synuclein wild-type only displayed neuronal loss in the hippocampus. These results support the hypothesis that accumulating oligomeric α-synuclein may

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Brain; Disease Models, Animal; Gene Expression Regulation; Glutamic Acid; Humans; Lewy Body Disease; Lysine; Memory Disorders; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Neurons; Synapses; Thy-1 Antigens

Parkinson's disease (PD) is characterized by progressive loss of dopaminergic neurons and aggregation of alpha synuclein (αS) in the brain. The role of epicatechin gallate (EG) was studied on the transgenic Drosophila model of flies expressing normal human alpha synuclein (h-αS) in the neurons. The objectives of the present work include the study of the effect of EG on the climbing ability, lipid peroxidation, and apoptosis in the brain of PD model flies. These flies exhibit locomotor dysfunction as the age progresses. EG at final concentration of 0.25, 0.50, and 1.0 μg/mL was supplemented in diet and flies were allowed to feed for 24 days. The climbing ability was assessed after 24 days. The supplementation of 0.25, 0.50, and 1.0 μg/mL of EG showed a dose-dependent significant delay in the loss of climbing ability and reduced the oxidative stress and apoptosis in the brain of PD model flies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antioxidants; Apoptosis; Brain; Camellia sinensis; Catechin; Dietary Supplements; Disease Models, Animal; Dopaminergic Neurons; Dose-Response Relationship, Drug; Drosophila melanogaster; Drosophila Proteins; Humans; Lipid Peroxidation; Locomotion; Oxidative Stress; Parkinson Disease; Phytotherapy; Plant Extracts

Multiple system atrophy (MSA), an atypical parkinsonian disorder, is characterized by α-synuclein (α-syn(+)) cytoplasmatic inclusions in mature oligodendrocytes. Oligodendrocyte progenitor cells (OPCs) represent a distinct cell population with the potential to replace dysfunctional oligodendrocytes. However, the role of OPCs in MSA and their potential to replace mature oligodendrocytes is still unclear. A postmortem analysis in MSA patients revealed α-syn within OPCs and an increased number of striatal OPCs. In an MSA mouse model, an age-dependent increase of dividing OPCs within the striatum and the cortex was detected. Despite of myelin loss, there was no reduction of mature oligodendrocytes in the corpus callosum or the striatum. Dissecting the underlying molecular mechanisms an oligodendroglial cell line expressing human α-syn revealed that α-syn delays OPC maturation by severely downregulating myelin-gene regulatory factor and myelin basic protein. Brain-derived neurotrophic factor was reduced in MSA models and its in vitro supplementation partially restored the phenotype. Taken together, efficacious induction of OPC maturation may open the window to restore glial and neuronal function in MSA.

Topics: Aged; Aged, 80 and over; Aging; alpha-Synuclein; Animals; Cell Differentiation; Cell Proliferation; Cells, Cultured; Cerebral Cortex; Corpus Striatum; Disease Models, Animal; Female; Humans; Male; Mice, Transgenic; Middle Aged; Multiple System Atrophy; Oligodendroglia; Stem Cells

The misfolding and aggregation of α-synuclein (aSyn) eventually lead to an accumulation of toxic forms that disturb normal neuronal function and result in cell death. aSyn rich inclusions are seen in Parkinson's disease, dementia with Lewy bodies and other synucleinopathies. Prolyl oligopeptidase (PREP) can accelerate the aggregation process of aSyn and the inhibition of PREP leads to a decreased amount of aggregated aSyn in cell models and in aSyn transgenic mice. In this study, we investigated the effect of 5- and 28-day PREP inhibitor (KYP-2047) treatments on a mouse strain carrying a point mutation in the aSyn coding gene. Following PREP inhibition, we found a decrease in high molecular-weight oligomeric aSyn and a concomitant increase in the amount of the autophagosome marker, LC3BII, suggesting enhanced macroautophagy (autophagy) and aSyn clearance by KYP-2047. Moreover, 28-day treatment with KYP-2047 caused significant increases in striatal dopamine levels. In cell culture, overexpression of PREP reduced the autophagy. Furthermore, the inhibition of PREP normalized the changes on autophagy markers (LC3BII and p62) caused by an autophagy inhibition or aSyn overexpression, and induced the expression of beclin 1, a positive regulator of autophagy. Taken together, our results suggest that PREP inhibition accelerates the clearance of protein aggregates via increased autophagy and thus normalizes the cell functions in vivo and in vitro. Therefore, PREP inhibition may have future potential in the treatment of synucleinopathies.

Topics: Alanine; alpha-Synuclein; Animals; Autophagy; Brain; Brain Diseases; Cell Line, Transformed; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Mutation; Proline; Prolyl Oligopeptidases; Serine Endopeptidases; Serine Proteinase Inhibitors; Time Factors

Parkinson׳s disease (PD) is a common neurodegenerative disorder characterized by the selective degeneration of projecting dopaminergic neurons in the substantia nigra and diminished dopamine levels in the striatum. Accumulating evidences demonstrate that the aggregation of extracellular α-synuclein contributes to the neuroinflammation and neuronal injury in the substantia nigra in the brain of patients with PD. Proteinase-activated receptor 2 (PAR2), a G-protein coupled receptor, is expressed throughout the peripheral and central nerve system. The present study aims to investigate the involvement of PAR2-NF-κB signaling in the upregulation of α-synuclein and motor dysfunction in the rodent model of PD. Significantly increased expression of α-synuclein was observed in the substantia nigra of the rats injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In these rats, significantly increased nigral PAR2 was observed, and blockade of PAR2 signaling reduced the α-synuclein synthesis in substantia nigra and recovered the motor dysfunction in the rats injected with MPTP. Furthermore, significantly increased phosphorylation of NF-κB subunit p65 was detected in these rats, which was abolished by the inhibition of PAR2 signaling. Blockade of NF-κB signaling significantly decreased histone H3 acetylation in Snca promoter region and α-synuclein expression in substantia nigra. It also decreased the synthesis of cytokine IL-1β and TNF-α in substantia nigra and recovered the motor dysfunction in the rats injected with MPTP. These results indicated the critical involvement of PAR2-NF-κB signaling in the upregulation of α-synuclein and motor dysfunction in the rodent model of PD, and shed light on the development of novel approaches for the treatment of patients with PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Epigenesis, Genetic; Male; MPTP Poisoning; NF-kappa B; Phosphorylation; Rats; Rats, Wistar; Receptor, PAR-2; Substantia Nigra; Up-Regulation

Proteins aggregate in several slowly progressive neurodegenerative diseases called 'proteinopathies'. Studies with cell cultures and transgenic mice overexpressing mutated proteins suggested that aggregates of one protein induced misfolding and aggregation of other proteins as well - a possible common mechanism for some neurodegenerative diseases. However, most proteinopathies are 'sporadic', without gene mutation or overexpression. Thus, proteinopathies in WT animals genetically close to humans might be informative. Squirrel monkeys infected with the classical bovine spongiform encephalopathy agent developed an encephalopathy resembling variant Creutzfeldt-Jakob disease with accumulations not only of abnormal prion protein (PrP(TSE)), but also three other proteins: hyperphosphorylated tau (p-tau), α-synuclein and ubiquitin; β-amyloid protein (Aβ) did not accumulate. Severity of brain lesions correlated with spongiform degeneration. No amyloid was detected. These results suggested that PrP(TSE) enhanced formation of p-tau and aggregation of α-synuclein and ubiquitin, but not Aβ, providing a new experimental model for neurodegenerative diseases associated with complex proteinopathies.

Topics: alpha-Synuclein; Animals; Brain; Cattle; Disease Models, Animal; Encephalopathy, Bovine Spongiform; Prions; Saimiri; tau Proteins; Ubiquitin

Communication and swallowing deficits are common in Parkinson's disease (PD). Evidence indicates that voice and speech dysfunction manifest early, prior to motor deficits typically associated with striatal dopamine loss. Unlike deficits in the extremities, cranial sensorimotor deficits are refractory to standard dopamine-related pharmacological and surgical interventions, thus the mechanisms underlying vocal deficits are unclear. Although neurotoxin models have provided some insight, they typically model nigrostriatal dopamine depletion and are therefore limited. Widespread alpha-synuclein (aSyn) pathology is common to familial and sporadic PD, and transgenic mouse models based on aSyn overexpression present a unique opportunity to explore vocalization deficits in relation to extrastriatal, nondopaminergic pathologies. Specifically, mice overexpressing human wild-type aSyn under a broad neuronal promoter (Thy1-aSyn) present early, progressive motor and nonmotor deficits starting at 2-3 months, followed by parkinsonism with dopamine loss at 14 months. We recorded ultrasonic vocalizations from Thy1-aSyn mice and wild-type (WT) controls at 2-3, 6-7, and 9 months. Thy1-aSyn mice demonstrated early, progressive vocalization deficits compared with WT. Duration and intensity of calls were significantly reduced and call profile was altered in the Thy1-aSyn mice, particularly at 2-3 months. Call rate trended toward a more drastic decrease with age in the Thy1-aSyn mice compared with WT. Alpha-synuclein pathology is present in the periaqueductal gray and may underlie the manifestation of vocalization deficits. These results indicate that aSyn overexpression can induce vocalization deficits at an early age in mice and provides a new model for studying the mechanisms underlying cranial sensorimotor deficits and treatment interventions for PD.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; Vocalization, Animal

Age-related neurodegeneration has been studied extensively through the use of model organisms, including the genetically versatile Drosophila melanogaster. Various neurotoxic proteins have been expressed in fly eyes to approximate degeneration occurring in humans, and much has been learned from this heterologous system. Although Drosophila expedites scientific research through rapid generational times and relative inexpensiveness, one factor that can hinder analyses is the examination of milder forms of degeneration caused by some toxic proteins in fly eyes. Whereas several disease proteins cause massive degeneration that is easily observed by examining the external structure of the fly eye, others cause mild degeneration that is difficult to observe externally and requires laborious histological preparation to assess and monitor. Here, we describe a sensitive fluorescence-based method to observe, monitor, and quantify mild Drosophila eye degeneration caused by various proteins, including the polyglutamine disease proteins ataxin-3 (spinocerebellar ataxia type 3) and huntingtin (Huntington's disease), mutant α-synuclein (Parkinson's disease), and Aβ42 (Alzheimer's disease). We show that membrane-targeted green fluorescent protein reports degeneration robustly and quantitatively. This simple yet powerful technique, which is amenable to large-scale screens, can help accelerate studies to understand age-related degeneration and to find factors that suppress it for therapeutic purposes.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Ataxin-3; CD8 Antigens; Disease Models, Animal; Drosophila; Drosophila melanogaster; Drosophila Proteins; Green Fluorescent Proteins; Humans; Huntingtin Protein; Mice, Transgenic; Microtubule-Associated Proteins; Nerve Tissue Proteins; Nuclear Proteins; Peptide Fragments; Peptides; Repressor Proteins; Retinal Degeneration; Transcription Factors

Subpopulations of dopaminergic (DA) neurons within the substantia nigra pars compacta (SNpc) display a differential vulnerability to loss in Parkinson's disease (PD); however, it is not clear why these subsets are preferentially selected in PD-associated neurodegeneration. In rodent SNpc, DA neurons can be divided into two subpopulations based on the expression of aldehyde dehydrogenase 1 (ALDH1A1). Here, we have shown that, in α-synuclein transgenic mice, a murine model of PD-related disease, DA neurodegeneration occurs mainly in a dorsomedial ALDH1A1-negative subpopulation that is also prone to cytotoxic aggregation of α-synuclein. Notably, the topographic ALDH1A1 pattern observed in α-synuclein transgenic mice was conserved in human SNpc. Postmortem evaluation of brains of patients with PD revealed a severe reduction of ALDH1A1 expression and neurodegeneration in the ventral ALDH1A1-positive DA subpopulations. ALDH1A1 expression was also suppressed in α-synuclein transgenic mice. Deletion of Aldh1a1 exacerbated α-synuclein-mediated DA neurodegeneration and α-synuclein aggregation, whereas Aldh1a1-null and control DA neurons were comparably susceptible to 1-methyl-4-phenylpyridinium-, glutamate-, or camptothecin-induced cell death. ALDH1A1 overexpression appeared to preferentially protect against α-synuclein-mediated DA neurodegeneration but did not rescue α-synuclein-induced loss of cortical neurons. Together, our findings suggest that ALDH1A1 protects subpopulations of SNpc DA neurons by preventing the accumulation of dopamine aldehyde intermediates and formation of cytotoxic α-synuclein oligomers.

Topics: Aldehyde Dehydrogenase; Aldehyde Dehydrogenase 1 Family; alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Female; Humans; Male; Mice; Mice, Knockout; Mice, Mutant Strains; Mice, Transgenic; Mutant Proteins; Mutation, Missense; Nerve Degeneration; Parkinson Disease; Protein Multimerization; Recombinant Proteins; Retinal Dehydrogenase; Substantia Nigra