alpha-synuclein and Parkinsonian-Disorders

Parkinsonism is a complex neurodegenerative disease that is difficult to differentiate because of its idiopathic and unknown origins. The hereditary parkinsonism known as autosomal recessive-juvenile parkinsonism (AR-JP) is marked by tremors, dyskinesias, dystonic characteristics, and manifestations that improve sleep but do not include dementia. This was caused by deletions and point mutations in PARK2 (chromosome 6q25.2-27). Diminished or unusual sensations (paresthesias), loss of neuron strength both in the CNS and peripheral nerves, and lack of motor coordination are the hallmarks of neuropathy in parkinsonism. The incidence of parkinsonism during oxidative stress and ageing is associated with parkinopathy. Parkinopathy is hypothesized to be triggered by mutation of the parkin (PRKN) gene and loss of normal physiological functions of PRKN proteins, which triggers their pathogenic aggregation due to conformational changes. Two important genes that control mitochondrial health are PRKN and phosphatase and tensin homologue deleted on chromosome 10-induced putative kinase 1 (PINK1). Overexpression of TAR DNA-binding protein-43 (TDP-43) increases the aggregation of insoluble PRKN proteins in OMM. Foreign α-synuclein (ASN) promotes parkinopathy via S-nitrosylation and hence has a neurotoxic effect on dopaminergic nerves. Miro1 (Miro GTPase1), a member of the RAS superfamily, is expressed in nerve cells. Due to PINK1/PRKN and Miro1's functional relationship, an excess of mitochondrial calcium culminates in the destruction of dopaminergic neurons. An interlinked understanding of TDP-43, PINK1/PRKN, ASN, and Miro1 signalling in the communication among astrocytes, microglia, neurons, and immune cells within the brain explored the pathway of neuronal death and shed light on novel strategies for the diagnosis and treatment of parkinsonism.

Topics: alpha-Synuclein; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Parkinsonian Disorders; Protein Kinases; rho GTP-Binding Proteins; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is a progressive neurodegenerative disorder that primarily affects elderly people and constitutes a major source of disability worldwide. Notably, the neuropathological hallmarks of PD include nigrostriatal loss and the formation of intracellular inclusion bodies containing misfolded α-synuclein protein aggregates. Cardinal motor symptoms, which include tremor, rigidity and bradykinesia, can effectively be managed with dopaminergic therapy for years following symptom onset. Nonetheless, patients ultimately develop symptoms that no longer fully respond to dopaminergic treatment. Attempts to discover disease-modifying agents have increasingly been supported by translational molecular imaging concepts, targeting the most prominent pathological hallmark of PD, α-synuclein accumulation, as well as other molecular pathways that contribute to the pathophysiology of PD. Indeed, molecular imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can be leveraged to study parkinsonism not only in animal models but also in living patients. For instance, mitochondrial dysfunction can be assessed with probes that target the mitochondrial complex I (MC-I), while nigrostriatal degeneration is typically evaluated with probes designed to non-invasively quantify dopaminergic nerve loss. In addition to dopaminergic imaging, serotonin transporter and N-methyl-D-aspartate (NMDA) receptor probes are increasingly used as research tools to better understand the complexity of neurotransmitter dysregulation in PD. Non-invasive quantification of neuroinflammatory processes is mainly conducted by targeting the translocator protein 18 kDa (TSPO) on activated microglia using established imaging agents. Despite the overwhelming involvement of the brain and brainstem, the pathophysiology of PD is not restricted to the central nervous system (CNS). In fact, PD also affects various peripheral organs such as the heart and gastrointestinal tract - primarily via autonomic dysfunction. As such, research into peripheral biomarkers has taken advantage of cardiac autonomic denervation in PD, allowing the differential diagnosis between PD and multiple system atrophy with probes that visualize sympathetic nerve terminals in the myocardium. Further, α-synuclein has recently gained attention as a potential peripheral biomarker in PD. This review discusses breakthrough discoveries that have led to the contemporary mol

Topics: alpha-Synuclein; Animals; Dopamine; Drug Development; Molecular Imaging; Parkinson Disease; Parkinsonian Disorders

Multiple system atrophy (MSA) is a debilitating movement disorder with unknown etiology. Patients present characteristic parkinsonism and/or cerebellar dysfunction in the clinical phase, resulting from progressive deterioration in the nigrostriatal and olivopontocerebellar regions. MSA patients have a prodromal phase subsequent to the insidious onset of neuropathology. Therefore, understanding the early pathological events is important in determining the pathogenesis, which will assist with developing disease-modifying therapy. Although the definite diagnosis of MSA relies on the positive post-mortem finding of oligodendroglial inclusions composed of α-synuclein, only recently has MSA been verified as an oligodendrogliopathy with secondary neuronal degeneration. We review up-to-date knowledge of human oligodendrocyte lineage cells and their association with α-synuclein, and discuss the postulated mechanisms of how oligodendrogliopathy develops, oligodendrocyte progenitor cells as the potential origins of the toxic seeds of α-synuclein, and the possible networks through which oligodendrogliopathy induces neuronal loss. Our insights will shed new light on the research directions for future MSA studies.

Topics: alpha-Synuclein; Cell Lineage; Humans; Multiple System Atrophy; Neurons; Parkinsonian Disorders

Parkinsonian disorders, such as Parkinson's disease (PD), multiple system atrophy (MSA), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS), share early motor symptoms but have distinct pathophysiology. As a result, accurate premortem diagnosis is challenging for neurologists, hindering efforts for disease-modifying therapeutic discovery. Extracellular vesicles (EVs) contain cell-state-specific biomolecules and can cross the blood-brain barrier to the peripheral circulation, providing a unique central nervous system (CNS) insight. This meta-analysis evaluated blood-isolated neuronal and oligodendroglial EVs (nEVs and oEVs) α-synuclein levels in Parkinsonian disorders.. Following PRISMA guidelines, the meta-analysis included 13 studies. An inverse-variance random-effects model quantified effect size (SMD), QUADAS-2 assessed risk of bias and publication bias was evaluated. Demographic and clinical variables were collected for meta-regression.. The meta-analysis included 1,565 patients with PD, 206 with MSA, 21 with DLB, 172 with PSP, 152 with CBS and 967 healthy controls (HCs). Findings suggest that combined concentrations of nEVs and oEVs α-syn is higher in patients with PD compared to HCs (SMD = 0.21, p = 0.021), while nEVs α-syn is lower in patients with PSP and CBS compared to patients with PD (SMD = -1.04, p = 0.0017) or HCs (SMD = -0.41, p < 0.001). Additionally, α-syn in nEVs and/or oEVs did not significantly differ in patients with PD vs. MSA, contradicting the literature. Meta-regressions show that demographic and clinical factors were not significant predictors of nEVs or oEVs α-syn concentrations.. The results highlight the need for standardized procedures and independent validations in biomarker studies and the development of improved biomarkers for distinguishing Parkinsonian disorders.

Topics: alpha-Synuclein; Biomarkers; Central Nervous System; Extracellular Vesicles; Humans; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease after Alzheimer's disease, globally. Dopaminergic neuron degeneration in substantia nigra pars compacta and aggregation of misfolded alpha-synuclein are the PD hallmarks, accompanied by motor and non-motor symptoms. Several viruses have been linked to the appearance of a post-infection parkinsonian phenotype. Coronavirus disease 2019 (COVID-19), caused by emerging severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, has evolved from a novel pneumonia to a multifaceted syndrome with multiple clinical manifestations, among which neurological sequalae appear insidious and potentially long-lasting. Exosomes are extracellular nanovesicles bearing a complex cargo of active biomolecules and playing crucial roles in intercellular communication under pathophysiological conditions. Exosomes constitute a reliable route for misfolded protein transmission, contributing to PD pathogenesis and diagnosis. Herein, we summarize recent evidence suggesting that SARS-CoV-2 infection shares numerous clinical manifestations and inflammatory and molecular pathways with PD. We carry on hypothesizing that these similarities may be reflected in exosomal cargo modulated by the virus in correlation with disease severity. Travelling from the periphery to the brain, SARS-CoV-2-related exosomal cargo contains SARS-CoV-2 RNA, viral proteins, inflammatory mediators, and modified host proteins that could operate as promoters of neurodegenerative and neuroinflammatory cascades, potentially leading to a future parkinsonism and PD development.

Topics: alpha-Synuclein; Cell Communication; COVID-19; Humans; Neurodegenerative Diseases; Parkinson Disease; Parkinsonian Disorders; RNA, Viral; SARS-CoV-2

Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by parkinsonism, cerebellar impairment, and autonomic failure. Although the causes of MSA onset and progression remain uncertain, its pathogenesis may involve oxidative stress via the generation of excess reactive oxygen species and/or destruction of the antioxidant system. One of the most powerful antioxidants is glutathione, which plays essential roles as an antioxidant enzyme cofactor, cysteine-storage molecule, major redox buffer, and neuromodulator, in addition to being a key antioxidant in the central nervous system. Glutathione levels are known to be reduced in neurodegenerative diseases. In addition, genes regulating redox states have been shown to be post-transcriptionally modified by microRNA (miRNA), one of the most important types of non-coding RNA. miRNAs have been reported to be dysregulated in several diseases, including MSA. In this review, we focused on the relation between glutathione deficiency, miRNA dysregulation and oxidative stress and their close relation with MSA pathology.

Topics: alpha-Synuclein; Antioxidants; Cerebellum; Glutathione; Humans; MicroRNAs; Multiple System Atrophy; Parkinsonian Disorders

Multiple system atrophy (MSA) is a rapidly progressive, fatal neurodegenerative disease of uncertain aetiology that belongs to the family of α-synucleinopathies. It clinically presents with parkinsonism, cerebellar, autonomic, and motor impairment in variable combinations. Pathological hallmarks are fibrillary α-synuclein (αSyn)-rich glial cytoplasmic inclusions (GCIs) mainly involving oligodendroglia and to a lesser extent neurons, inducing a multisystem neurodegeneration, glial activation, and widespread demyelinization. The neuronal αSyn pathology of MSA has molecular properties different from Lewy bodies in Parkinson's disease (PD), both of which could serve as a pool of αSyn (prion) seeds that could initiate and drive the pathogenesis of synucleinopathies. The molecular cascade leading to the "prion-like" transfer of "strains" of aggregated αSyn contributing to the progression of the disease is poorly understood, while some presented evidence that MSA is a prion disease. However, this hypothesis is difficult to reconcile with postmortem analysis of human brains and the fact that MSA-like pathology was induced by intracerebral inoculation of human MSA brain homogenates only in homozygous mutant 53T mice, without production of disease-specific GCIs, or with replication of MSA prions in primary astrocyte cultures from transgenic mice expressing human αSyn. Whereas recent intrastriatal injection of Lewy body-derived or synthetic human αSyn fibrils induced PD-like pathology including neuronal αSyn aggregates in macaques, no such transmission of αSyn pathology in non-human primates by MSA brain lysate has been reported until now. Given the similarities between αSyn and prions, there is a considerable debate whether they should be referred to as "prions", "prion-like", "prionoids", or something else. Here, the findings supporting the proposed nature of αSyn as a prion and its self-propagation through seeding as well as the transmissibility of neurodegenerative disorders are discussed. The proof of disease causation rests on the concordance of scientific evidence, none of which has provided convincing evidence for the classification of MSA as a prion disease or its human transmission until now.

Topics: alpha-Synuclein; Animals; Astrocytes; Brain; Humans; Inclusion Bodies; Lewy Bodies; Macaca; Mice; Mice, Transgenic; Models, Theoretical; Multiple System Atrophy; Neurodegenerative Diseases; Neuroglia; Neurons; Parkinson Disease; Parkinsonian Disorders; Prions; Protein Folding

Parkinson's disease (PD), dementia with Lewy body (DLB), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy (MSA) belong to a group of neurodegenerative diseases called parkinsonian syndromes. They share several clinical, neuropathological and genetic features. Neurodegenerative diseases are characterized by the progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra- and intracellular accumulation of misfolded proteins. The parkinsonian diseases affect distinct areas of the brain. PD and MSA belong to a group of synucleinopathies that are characterized by the presence of fibrillary aggregates of α-synuclein protein in the cytoplasm of selected populations of neurons and glial cells. PSP is a tauopathy associated with the pathological aggregation of the microtubule associated tau protein. Although PD is common in the world's aging population and has been extensively studied, the exact mechanisms of the neurodegeneration are still not fully understood. Growing evidence indicates that parkinsonian disorders to some extent share a genetic background, with two key components identified so far: the microtubule associated tau protein gene (

Topics: alpha-Synuclein; Animals; Brain; Genetic Predisposition to Disease; Humans; Mitochondria; Mitophagy; Nerve Degeneration; Neurons; Oxidative Stress; Parkinsonian Disorders; Phenotype; Risk Factors; tau Proteins

Parkinson's disease (PD) is a movement disorder associated with severe loss of mainly dopaminergic neurons in the substantia nigra. Pathological hallmarks include Lewy bodies, and loss of neuromelanin, due to degeneration of neuromelanin-containing dopaminergic neurons. Despite being described over 200 years ago, the etiology of PD remains unknown. Here, we highlight the roles of reactive oxygen species (ROS), iron, alpha synuclein (α-syn) and neuromelanin in a toxic feedback loop culminating in neuronal death and spread of the disease. Dopaminergic neurons are particularly vulnerable due to decreased antioxidant concentration with aging, constant exposure to ROS and presence of neurotoxic compounds (e.g. ortho-quinones). ROS and iron increase each other's levels, creating a state of oxidative stress. α-Syn aggregation is influenced by ROS and iron but also increases ROS and iron via its induced mitochondrial dysfunction and ferric-reductase activity. Neuromelanin's binding affinity is affected by increased ROS and iron. Furthermore, during neuronal death, neuromelanin is degraded in the extracellular space, releasing its bound toxins. This cycle of events continues to neighboring neurons in the form of a toxic loop, causing PD pathology. The increase in ROS and iron may be an important target for therapies to disrupt this toxic loop, and therefore diets rich in certain 'nutraceuticals' may be beneficial. Turmeric is an attractive candidate, as it is known to have anti-oxidant and iron chelating properties. More studies are needed to test this theory and if validated, this would be a step towards development of lifestyle-based therapeutic modalities to complement existing PD treatments.

Topics: alpha-Synuclein; Animals; Autophagy; Brain Chemistry; Curcuma; Dopamine; Dopaminergic Neurons; Feedback, Physiological; Ferroptosis; Homeostasis; Humans; Iron; Melanins; Mice; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Phytotherapy; Protein Aggregation, Pathological; Reactive Oxygen Species; Substantia Nigra

Parkinson's disease (PD) is a movement disorder identified more than 200 years ago; today it is defined by specific motor symptoms that together receive the name of parkinsonism. PD diagnosis is reached with the full parkinsonian syndrome, but in recent years, a series of non-motor symptoms have arisen as intrinsic components of PD. These non-motor symptoms are variable, creating a widely heterogenous disease presentation. Some non-motor symptoms appear in late disease stages and are explained as the natural progression of PD pathology into other brain centres, including the frontal cortex. Other symptoms can appear a decade or earlier preceding PD diagnosis, particularly hyposmia (loss of smell) and constipation. These early symptoms and the accompanying protein pathology have stimulated a lively conversation about the origin and nature of PD and other related conditions: some authors propose that PD starts in the olfactory mucosa and the gut due to direct exposure to toxins or pathogens. This pathology then travels by anatomically interconnected networks to the midbrain to cause motor symptoms and the cortex to cause late complications. Other models propose that PD develops in multiple independent foci that do not require pathology spread. We will review these hypotheses in the context of recent developments regarding the spread of amyloids and propose a mixed model where a multifocal origin explains the variable presentation of PD, while cell-to-cell spread explains stereotypical disease progression.

Topics: alpha-Synuclein; Disease Progression; Dopamine; Frontal Lobe; Humans; Olfactory Mucosa; Parkinson Disease; Parkinsonian Disorders; Serum Amyloid A Protein

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by motor symptoms such as tremor, slowness of movement, rigidity, and postural instability, as well as non-motor features like sleep disturbances, loss of ability to smell, depression, constipation, and pain. Motor symptoms are caused by depletion of dopamine in the striatum due to the progressive loss of dopamine neurons in the substantia nigra pars compacta. Approximately 10% of PD cases are familial arising from genetic mutations in α-synuclein, LRRK2, DJ-1, PINK1, parkin, and several other proteins. The majority of PD cases are, however, idiopathic, i.e., having no clear etiology. PD is characterized by progressive accumulation of insoluble inclusions, known as Lewy bodies, mostly composed of α-synuclein and membrane components. The cause of PD is currently attributed to cellular proteostasis deregulation and mitochondrial dysfunction, which are likely interdependent. In addition, neuroinflammation is present in brains of PD patients, but whether it is the cause or consequence of neurodegeneration remains to be studied. Rodents do not develop PD or PD-like motor symptoms spontaneously; however, neurotoxins, genetic mutations, viral vector-mediated transgene expression and, recently, injections of misfolded α-synuclein have been successfully utilized to model certain aspects of the disease. Here, we critically review the advantages and drawbacks of rodent PD models and discuss approaches to advance pre-clinical PD research towards successful disease-modifying therapy. © 2020 The Authors.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Dopaminergic Neurons; Drug Evaluation, Preclinical; Forecasting; Genome-Wide Association Study; Histological Techniques; Humans; Mice; Mice, Transgenic; Nerve Tissue Proteins; Neuroprotective Agents; Neurotoxins; Parkinson Disease; Parkinsonian Disorders; Pesticides; Protein Aggregation, Pathological; Rats; Substantia Nigra; Synucleinopathies

Neuronal homeostasis depends on both simple and complex sugars (the glycoconjugates), and derangement of their metabolism is liable to impair neural function and lead to neurodegeneration. Glucose levels boost glycation phenomena, a wide series of non-enzymatic reactions that give rise to various intermediates and end-products that are potentially dangerous in neurons. Glycoconjugates, including glycoproteins, glycolipids, and glycosaminoglycans, contribute to the constitution of the unique features of neuron membranes and extracellular matrix in the nervous system. Glycosylation defects are indeed frequently associated with nervous system disturbances and neurodegeneration. Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms associated with the loss of dopaminergic neurons in the pars compacta of the substantia nigra. Neurons present intracytoplasmic inclusions of α-synuclein aggregates involved in the disease pathogenesis together with the impairment of the autophagy-lysosome function, oxidative stress, and defective traffic and turnover of membrane components. In the present review, we selected relevant recent contributions concerning the direct involvement of glycation and glycosylation in α-synuclein stability, impaired autophagy and lysosomal function in PD, focusing on potential models of PD pathogenesis provided by genetic variants of glycosphingolipid processing enzymes, especially glucocerebrosidase (GBA). Moreover, we collected data aimed at defining the glycomic profile of PD patients as a tool to help in diagnosis and patient subtyping, as well as those pointing to sugar-related compounds with potential therapeutic applications in PD.

Topics: alpha-Synuclein; Animals; Autophagy; Dopaminergic Neurons; Glucose; Glycoconjugates; Humans; Inclusion Bodies; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders

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

In recent years, a precision medicine approach, which customizes medical treatments based on patients' individual profiles and incorporates variability in genes, the environment, and lifestyle, has transformed medical care in numerous medical fields, most notably oncology. Applying a similar approach to Parkinson's disease (PD) may promote the development of disease-modifying agents that could help slow progression or possibly even avert disease development in a subset of at-risk individuals. The urgent need for such trials partially stems from the negative results of clinical trials where interventions treat all PD patients as a single homogenous group. Here, we review the current obstacles towards the development of precision interventions in PD. We also review and discuss the clinical trials that target genetic forms of PD, i.e., GBA-associated and LRRK2-associated PD.

Topics: alpha-Synuclein; Clinical Trials as Topic; Deep Brain Stimulation; Genetic Predisposition to Disease; Genetic Therapy; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Parkinsonian Disorders; Precision Medicine

Parkinson's disease (PD) is a neurodegenerative disorder, caused by, so far, unknown pathogenetic mechanisms. There is no doubt that pro-inflammatory immune-mediated mechanisms are pivotal to the pathogenicity and progression of the disease. In this review, we highlight the binary role of microglia activation in the pathophysiology of the disorder, both neuroprotective and neuromodulatory. We present how the expression of several cytokines implicated in dopaminergic neurons (DA) degeneration could be used as biomarkers for PD. Viral infections have been studied and correlated to the disease progression, usually operating as trigger factors for the inflammatory process. The gut-brain axis and the possible contribution of the peripheral bowel inflammation to neuronal death, mainly dopaminergic neurons, seems to be a main contributor of brain neuroinflammation. The role of the immune system has also been analyzed implicating a-synuclein in the activation of innate and adaptive immunity. We also discuss therapeutic approaches concerning PD and neuroinflammation, which have been studied in experimental and in vitro models and data stemming from epidemiological studies.

Topics: alpha-Synuclein; Animals; Autoimmunity; Biomarkers; Cytokines; Dopaminergic Neurons; Humans; Inflammation; Microglia; Nerve Degeneration; Parkinson Disease; Parkinsonian Disorders; Signal Transduction; Virus Diseases

Parkinson's disease (PD) patients have higher rates of melanoma and vice versa, observations suggesting that the two conditions may share common pathogenic pathways. β-Catenin is a transcriptional cofactor that, when concentrated in the nucleus, upregulates the expression of canonical Wnt target genes, such as Nurr1, many of which are important for neuronal survival. β-Catenin-mediated activity is decreased in sporadic PD as well as in leucine-rich repeat kinase 2 (LRRK2) and β-glucosidase (GBA) mutation cellular models of PD, which is the most common genetic cause of and risk for PD, respectively. In addition, β-catenin expression is significantly decreased in more aggressive and metastatic melanoma. Multiple observational studies have shown smokers to have significantly lower rates of PD as well as melanoma implying that tobacco may contain one or more elements that protect against both conditions. In support, smoker's brains have significantly reduced levels of α-synuclein, a pathological intracellular protein found in PD brain and melanoma cells. Tobacco contains very high lithium levels compared to other plants. Lithium has a broad array of neuroprotective actions, including enhancing autophagy and reducing intracellular α-synuclein levels, and is effective in both neurotoxin and transgenic preclinical PD models. One of lithium's neuroprotective actions is enhancement of β-catenin-mediated activity leading to increased Nurr1 expression through its ability to inhibit glycogen synthase kinase-3 β (GSK-3β). Lithium also has anti-proliferative effects on melanoma cells and the clinical use of lithium is associated with a reduced incidence of melanoma as well as reduced melanoma-associated mortality. This is the first known report hypothesizing that inhaled lithium from smoking may account for the associated reduced rates of both PD and melanoma and that this protection may be mediated, in part, through lithium-induced GSK-3β inhibition and consequent enhanced β-catenin-mediated activity. This hypothesis could be directly tested in clinical trials assessing lithium therapy's ability to affect β-catenin-mediated activity and slow disease progression in patients with PD or melanoma.

Topics: alpha-Synuclein; Alzheimer Disease; Autophagy; beta Catenin; beta-Glucosidase; Brain Chemistry; Drug Evaluation, Preclinical; Glycogen Synthase Kinase 3 beta; Humans; Incidence; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lithium; Lithium Carbonate; Melanoma; Models, Biological; Mutation; Neuroprotective Agents; Nicotiana; Nuclear Receptor Subfamily 4, Group A, Member 2; Parkinson Disease; Parkinsonian Disorders; Smokers; Water; Wnt Signaling Pathway

Progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal degeneration (CBD) are forms of parkinsonism. PSP and CBD are 4R tauopathies and clinicopathologic overlaps exist between these two disorders. Neuropsychiatric symptoms including apathy, depression, anxiety are common features in patients with PSP and CBD. Disinhibition and impulsive behavior are also frequently observed in PSP patients, whereas hallucinations are seen only occasionally. Severe derangement in several neurotransmitter systems may account for behavioral symptoms observed in PSP and CBD, but substitutive therapy is not effective. Recent advances in genetics, epidemiology, biomarkers, pathophysiology, molecular mechanisms, and, in particular, the availability of treatments that may modify disease progression are opening new hopes in the care of these devastating disorders. MSA is a synucleinopathy with well characterized motor and autonomic dysfunction. MSA patients frequently show the presence of rapid eye movement (REM) behavior disorders, but the impact of neuropsychiatric disturbances and cognitive impairment in MSA needs further study. The availability of animal models and recent advances in the pathophysiology of α-synuclein accumulation are shedding light on the disease, opening new avenues for possible treatments.

Topics: alpha-Synuclein; Basal Ganglia Diseases; Humans; Multiple System Atrophy; Neurodegenerative Diseases; Parkinsonian Disorders; Supranuclear Palsy, Progressive

Parkinson's disease (PD) is primarily a movement disorder driven by the loss of dopamine-producing neurons in the substantia nigra (SN). Early identification of the oxidative properties of dopamine implicated it as a potential source of oxidative stress in PD, yet few studies have investigated dopamine neurotoxicity in vivo. The discovery of PD-causing mutations in α-synuclein and the presence of aggregated α-synuclein in the hallmark Lewy body pathology of PD revealed another important player. Despite extensive efforts, the precise role of α-synuclein aggregation in neurodegeneration remains unclear. We recently manipulated both dopamine levels and α-synuclein expression in aged mice and found that only the combination of these 2 factors caused progressive neurodegeneration of the SN and an associated motor deficit. Dopamine modified α-synuclein aggregation in the SN, resulting in greater abundance of α-synuclein oligomers and unique dopamine-induced oligomeric conformations. Furthermore, disruption of the dopamine-α-synuclein interaction rescued dopaminergic neurons from degeneration in transgenic Caenorhabditis elegans models. In this Perspective, we discuss these findings in the context of known α-synuclein and dopamine biology, review the evidence for α-synuclein oligomer toxicity and potential mechanisms, and discuss therapeutic implications. © 2019 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Dopamine; Dopaminergic Neurons; Humans; Nerve Degeneration; Oxidative Stress; Parkinsonian Disorders

Our understanding of the biological basis of Parkinson's disease (PD) has been greatly improved in recent years by the identification of mutations that lead to inherited PD. One of the strengths of using genetics to try to understand disease biology is that it is inherently unbiased and can be applied at a genome-wide scale. More recently, many studies have used another set of unbiased approaches, proteomics, to query the function of familial PD genes in a variety of contexts. We will discuss some specific examples, including; elucidation of protein-protein interaction networks for two dominantly inherited genes, α-synuclein and leucine rich-repeat kinase 2 (LRRK2); the identification of substrates for three genes for familial PD that are also enzymes, namely LRRK2, pink1, and parkin; and changes in protein abundance that arise downstream to introduction of mutations associated with familial PD. We will also discuss those situations where we can integrate multiple proteomics approaches to nominate deeper networks of inter-related events that outline pathways relevant to inherited PD. This article is part of the Special Issue "Proteomics".

Topics: alpha-Synuclein; Genetic Predisposition to Disease; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mitochondria; Mutation; Parkinsonian Disorders; Protein Interaction Mapping; Proteome; Proteomics

Accumulation of alpha-synuclein protein aggregates is the hallmark neuropathologic feature of synucleinopathies such as Parkinson's disease. Rare point mutations and multiplications in SNCA, the gene encoding alpha-synuclein, as well as other genetic alterations are linked to familial Parkinson's disease cases with high penetrance and hence constitute major genetic risk factors for Parkinson's disease. However, the preponderance of cases seems sporadic, most likely based on a complex interplay between genetic predispositions, aging processes and environmental influences. Deciphering the impact of these environmental factors and their interactions with the individual genetic background in humans is challenging and often requires large cohorts, complicated study designs, and longitudinal set-ups. In contrast, rodent models offer an ideal system to study the influence of individual environmental aspects under controlled genetic background and standardized conditions. In this review, we highlight findings from studies examining effects of environmental enrichment mimicking stimulation of the brain by its physical and social surroundings as well as of environmental stressors on brain health in the context of Parkinson's disease. We discuss possible internal molecular transducers of such environmental cues in Parkinson's disease rodent models and emphasize their potential in developing novel avenues to much-needed therapies for this still incurable disease. This article is part of the Special Issue "Synuclein".

Topics: alpha-Synuclein; Animals; Brain; Diseases in Twins; Epigenesis, Genetic; Gene-Environment Interaction; Humans; Lewy Bodies; Mice; Mice, Knockout; Motor Activity; Parkinson Disease; Parkinsonian Disorders; Pesticides; Physical Stimulation; Protein Aggregation, Pathological; Risk Factors; Stress, Physiological; Stress, Psychological; Synucleinopathies

GBA1 mutations, which result in the lysosomal disorder Gaucher disease, are the most common known genetic risk factor for Parkinson disease and Dementia with Lewy Bodies (DLB). The pathogenesis of this association is not fully understood, but further elucidation of this link could lead to new therapeutic options.. The characteristic clinical phenotype of GBA1-PD resembles sporadic Parkinson disease, but with an earlier onset and more severe course. Many different GBA1 mutations increase the risk of Parkinson disease, some primarily detected in specific populations. Glucocerebrosidase deficiency appears to be associated with increased α-synuclein aggregation and accumulation, mitochondrial dysfunction because of impaired autophagy, and increased endoplasmic reticulum stress.. As our understanding of GBA1-associated Parkinson disease increases, new treatment opportunities emerge. MicroRNA profiles are providing examples of both up-regulated and down-regulated proteins related to GBA1 and may provide new therapeutic targets. Chaperone therapy, directed at either misfolded glucocerebrosidase or α-synuclein aggregation, is currently under development and there are several early clinical trials ongoing. Substrate reduction therapy, aimed at lowering the accumulation of metabolic by-products, especially glucosylsphingosine, is also being explored. Basic science insights from the rare disorder Gaucher disease are serving to catapult drug discovery for parkinsonism.

Topics: alpha-Synuclein; Gaucher Disease; Glucosylceramidase; Humans; Lewy Body Disease; Mutation; Parkinsonian Disorders; Protein Aggregates

Toll-like receptors (TLRs) are pattern recognition receptors which mediate an inflammatory response upon the detection of specific molecular patterns found on foreign organisms and on endogenous damage-related molecules. These receptors play a major role in the activation of microglia, the innate immune cells of the CNS, and are also expressed in peripheral tissues, including blood mononuclear cells and the gut. It is well established that immune activation, in both the brain and periphery, is a feature of Parkinson's disease as well as other α-synucleinopathies. Aggregated forms of α-synuclein can act as ligands for TLRs (particularly TLR2 and TLR4), and hence these receptors may play a critical role in mediating a detrimental immune response to this protein, as well as other inflammatory signals in Parkinson's and related α-synucleinopathies. In this review, the potential role of TLRs in contributing to the progression of these disorders is discussed. Existing evidence comes predominantly from studies in in vitro and in vivo models, as well as analyses of postmortem human brain tissue and pre-clinical studies of TLR inhibitors. This evidence is evaluated in detail, and the potential for therapeutic intervention in α-synucleinopathies through TLR inhibition is discussed.

Topics: alpha-Synuclein; Animals; Brain; Humans; Microglia; Parkinson Disease; Parkinsonian Disorders; Synucleinopathies; Toll-Like Receptor 2; Toll-Like Receptor 4; Toll-Like Receptors

Juvenile parkinsonism is arbitrarily defined as parkinsonian symptoms and signs presenting prior to 21 years of age. Levodopa-responsive juvenile parkinsonism that is consistent with diagnostic criteria for Parkinson's disease is most often caused by mutations in the PARK-Parkin, PARK-PINK1, or PARK-DJ1 genes. However, many other genetic and acquired parkinsonian disorders presenting in childhood or young adulthood are being reported, often with atypical features, such as presence of other movement disorders, cognitive decline, and psychiatric symptoms. The genetic landscape of juvenile parkinsonism is rapidly changing with the discovery of new genes. Although the mainstay of treatment remains levodopa, other symptomatic therapies such as botulinum toxin for focal dystonia, supportive medical therapies, and deep brain stimulation in select cases, may also be used to provide the most optimal long-term outcomes. Since the topic has not been reviewed recently, we aim to provide an update on genetics, differential diagnosis, evaluation, and treatment of juvenile parkinsonism.

Topics: Adolescent; alpha-Synuclein; Antiparkinson Agents; Child; Child, Preschool; Deep Brain Stimulation; Diagnosis, Differential; DiGeorge Syndrome; Dystonic Disorders; Genetic Diseases, X-Linked; Hepatolenticular Degeneration; Humans; Huntington Disease; Levodopa; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Spinocerebellar Ataxias; Ubiquitin-Protein Ligases; Young Adult

Among nutraceuticals, phytochemical-rich compounds represent a source of naturally-derived bioactive principles, which are extensively studied for potential beneficial effects in a variety of disorders ranging from cardiovascular and metabolic diseases to cancer and neurodegeneration. In the brain, phytochemicals produce a number of biological effects such as modulation of neurotransmitter activity, growth factor induction, antioxidant and anti-inflammatory activity, stem cell modulation/neurogenesis, regulation of mitochondrial homeostasis, and counteracting protein aggregation through modulation of protein-folding chaperones and the cell clearing systems autophagy and proteasome. In particular, the ability of phytochemicals in restoring proteostasis through autophagy induction took center stage in recent research on neurodegenerative disorders such as Parkinson's disease (PD). Indeed, autophagy dysfunctions and α-syn aggregation represent two interdependent downstream biochemical events, which concur in the parkinsonian brain, and which are targeted by phytochemicals administration. Therefore, in the present review we discuss evidence about the autophagy-based neuroprotective effects of specific phytochemical-rich plants in experimental parkinsonism, with a special focus on their ability to counteract alpha-synuclein aggregation and toxicity. Although further studies are needed to confirm the autophagy-based effects of some phytochemicals in parkinsonism, the evidence discussed here suggests that rescuing autophagy through natural compounds may play a role in preserving dopamine (DA) neuron integrity by counteracting the aggregation, toxicity, and prion-like spreading of α-syn, which remains a hallmark of PD.

Topics: alpha-Synuclein; Animals; Autophagy; Humans; Neuroprotective Agents; Parkinsonian Disorders; Phytochemicals; Proteolysis

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterised by a variable combination of autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal symptoms. The pathological hallmark is the oligodendrocytic glial cytoplasmic inclusion (GCI) consisting of α-synuclein; therefore, MSA is included in the category of α-synucleinopathies. MSA has been divided into two clinicopathological subtypes: MSA with predominant parkinsonism and MSA with predominant cerebellar ataxia, which generally correlate with striatonigral degeneration and olivopontocerebellar atrophy, respectively. It is increasingly recognised, however, that clinical and pathological features of MSA are broader than previously considered.In this review, we aim to describe recent advances in neuropathology of MSA from a review of the literature and from information derived from review of nearly 200 definite MSA cases in the Mayo Clinic Brain Bank. In light of these new neuropathological findings, GCIs and neuronal cytoplasmic inclusions play an important role in clinicopathological correlates of MSA. We also focus on clinical diagnostic accuracy and differential diagnosis of MSA as well as candidate biomarkers. We also review some controversial topics in MSA. Cognitive impairment, which has been a non-supporting feature of MSA, is considered from both clinical and pathological perspectives. The cellular origin of α-synuclein in GCI and a 'prion hypothesis' are discussed. Finally, completed and ongoing clinical trials targeting disease modification, including immunotherapy, are summarised.

Topics: alpha-Synuclein; Brain; Cerebellar Ataxia; Cognitive Dysfunction; Humans; Inclusion Bodies; Magnetic Resonance Imaging; Multiple System Atrophy; Neurons; Oligodendroglia; Parkinsonian Disorders; Positron-Emission Tomography; Prion Diseases

Parkinson's disease (PD) is a complex and heterogeneous neurological condition characterised mainly by bradykinesia, resting tremor, rigidity and postural instability, symptoms that together comprise the parkinsonian syndrome. Non-motor symptoms preceding and following clinical onset are also helpful diagnostic markers revealing a widespread and progressive pathology. Many other neurological conditions also include parkinsonism as primary or secondary symptom, confounding their diagnosis and treatment. Although overall disease course and end-stage pathological examination single out these conditions, the significant overlaps suggest that they are part of a continuous disease spectrum. Recent genetic discoveries support this idea because mutations in a few genes (α-synuclein,

Topics: alpha-Synuclein; Dopamine; Genes, Dominant; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mitochondria; Mutation; Neurons; Parkinson Disease; Parkinsonian Disorders; tau Proteins

Iron is essential for cellular development and maintenance of multiple physiological processes in the central nervous system. The disturbance of its homeostasis leads to abnormal iron deposition in the brain and causes neurotoxicity via generation of free radicals and oxidative stress. Iron toxicity has been established in the pathogenesis of Parkinson's disease; however, its contribution to multiple system atrophy (MSA) remains elusive. MSA is characterized by cytoplasmic inclusions of misfolded α-synuclein (α-SYN) in oligodendrocytes referred to as glial cytoplasmic inclusions (GCIs). Remarkably, the oligodendrocytes possess high amounts of iron, which together with GCI pathology make a contribution toward MSA pathogenesis likely. Consistent with this observation, the GCI density is associated with neurodegeneration in central autonomic networks as well as olivopontocerebellar and striatonigral pathways. Iron converts native α-SYN into a β-sheet conformation and promotes its aggregation either directly or via increasing levels of oxidative stress. Interestingly, α-SYN possesses ferrireductase activity and α-SYN expression underlies iron mediated translational control via RNA stem loop structures. Despite a correlation between progressive putaminal atrophy and iron accumulation as well as clinical decline, it remains unclear whether pathologic iron accumulation in MSA is a secondary event in the cascade of neuronal degeneration rather than a primary cause. This review summarizes the current knowledge of iron in MSA and gives evidence for perturbed iron homeostasis as a potential pathogenic factor in MSA-associated neurodegeneration.

Topics: alpha-Synuclein; Brain; Humans; Inclusion Bodies; Iron; Magnetic Resonance Imaging; Multiple System Atrophy; Oligodendroglia; Parkinsonian Disorders

This article reviews the epidemiological evidence of features of α-synucleinopathies that precede clinical onset of disease, proposes a clinical timeline, and attempts to define the different premotor and clinical phenotypes associated with α-synucleinopathies.. The pathological hallmarks of the α-synucleinopathies (Parkinson disease, Parkinson disease dementia, dementia with Lewy bodies, and multisystem atrophy) begin years before a clinical diagnosis. Epidemiologic studies support the long gap between pathology and symptoms and suggest that certain nonmotor conditions (constipation, anxiety, and rapid eye movement sleep behavior disorder) precede the traditional motor Parkinson disease phenotype by long intervals.. Characterizing the temporal onset of these conditions will help to better recognize the premotor phase of the α-synucleinopathies and specific clinical phenotypes and will guide the search for predictive biomarkers and risk or protective factors for Parkinson disease and other synucleinopathies.

Topics: alpha-Synuclein; Dementia; Humans; Multiple System Atrophy; Parkinsonian Disorders

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

Parkinson's disease (PD) is a progressive degenerative disease of the nervous system, which is characterized by movement disorders, such as static tremor, rigidity, and bradykinesia in advanced patients. Gastrointestinal (GI) dysfunction, such as gastric dysmotility, constipation, and anorectic dysfunction, is common non-motor symptom in the early stage of PD. The progression of PD includes the degenerative loss of dopaminergic (DA) neurons and aggregation of α-synuclein in the substantia nigra (SN). Interestingly, both of them are also present in the enteric nervous system (ENS) of PD patients. In this review, we describe the relationship between non-motor symptoms particularly GI dysfunction and the pathogenesis of PD, aiming to show the powerful evidences about the prion-like propagation of α-synuclein and support the hypothesis of gut-brain axis in PD. We then summarize the mechanism of the gut-brain axis and confirm α-synuclein as a potential target for drug design or new clinical treatment.

Topics: alpha-Synuclein; Animals; Brain; Enteric Nervous System; Humans; Parkinsonian Disorders; Prions

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the degeneration of dopaminergic neurons in the substantia nigra and the intraneuronal Lewy bodies in this area. Genetic mutations in PD pathogenesis have been explored and better understood in recent years. GBA variants are now considered to be the single largest risk factor for PD. Gaucher disease (GD) is a lysosomal storage disorder disease and an inherited deficiency of lysosomal glucocerebrosidase (GCase) arising from mutations in the gene GBA. A group of patients with GD exhibit parkinsonian symptoms, meanwhile, GBA mutations are more frequently observed in patients with PD. These lines of evidence suggest a close relationship between GBA mutations and PD. GBA mutations are associated with an earlier onset age and a distinct cognitive decline in PD. GCase loss-of-function caused by GBA mutations interferes with the degradation of α-synuclein, and α-synuclein pathology in turn inhibits normal GCase function in PD, which forms a vicious cycle. However, the exact mechanisms for this bidirectional pathogenic loop have not to be fully elucidated. In this review, we summarize the current understandings on the potential link between GBA mutations and PD pathogenesis, which may show novel insights into PD etiology and therapeutics.

Topics: alpha-Synuclein; Cognitive Dysfunction; Dopaminergic Neurons; Gaucher Disease; Glucosylceramidase; Humans; Mutation; Parkinson Disease; Parkinsonian Disorders; Risk Factors; Substantia Nigra

Parkinson disease has been considered for practical purposes a heterogeneous clinico-pathological entity. The operational definition requires clinical ascertainment of a levodopa-responsive parkinsonism with no "atypical" features, and pathological criteria based on the finding, usually at postmortem, of aggregates of α-synuclein in Lewy bodies and Lewy neurites. The underlying assumption has been that a molecular-biological disorder, targetable for disease modification as a whole, underlies this clinico-pathologic, convergent model of disease. The 2020s will be expected to mark the beginning of the end for this model, especially if therapeutic success in a specific molecular subtype, such as PD-GBA, is not translated to "sporadic PD". The complex and dynamic biological abnormalities of aging, which have informed the evolution of other fields in medicine into divergent, systems-biology models, will also provide the template for the development of disease modifying therapies for neurodegenerative disorders. In the 2020s and 2030s we will no longer ask whether any given molecule may be neuroprotective in early Parkinson disease but, rather, which subtype (which endophenotype) among the Parkinson diseases would be the best mechanistic recipient for such molecule and which would not. The next breakthrough in Parkinson's research will be conceptual: the recognition that discoveries in a subtype of PD will apply only or largely to that subtype and not construed to represent "a piece" that seamlessly inserts into, and helps explains, a unifying "Parkinson's puzzle". Successful neuroprotection for each PD subtype will likely require pharmacotherapeutic combinations ("drug cocktails") to harness synergistic potential benefits when more than the dominant pathogenic mechanism is targeted, as identified from forthcoming population-based unbiased biomarker discovery programs.

Topics: alpha-Synuclein; Brain; Disease Management; Humans; Lewy Bodies; Parkinson Disease; Parkinsonian Disorders; Systems Biology

Mutations in the SNCA gene, which encodes the α-synuclein protein, were the first discovered genetic causes of familial parkinsonism with Lewy pathology. To date, six different SNCA missense mutations as well as multiplications are known to cause parkinsonism. For this review, we performed a literature search to identify all published cases of SNCA-related parkinsonism to provide an updated summary of the clinical and neuropathological features of parkinsonism due to SNCA mutations. Familial parkinsonism associated with SNCA is rare, but α-synuclein aggregation is a core feature of sporadic parkinsonism, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Research into α-synuclein and parkinsonism has impacted how we define the pathology and understand the pathogenesis of Parkinson's disease and related neurodegenerative disorders. We briefly discuss some of the lessons we have learned from research into the physiological role of α-synuclein and its pathological links to neurodegeneration and parkinsonism.

Topics: alpha-Synuclein; Humans; Lewy Bodies; Mutation; Parkinsonian Disorders; Phenotype

Clinical-pathological studies remain the gold-standard for the diagnosis of Parkinson's disease (PD). However, mounting data from genetic PD autopsies challenge the diagnosis of PD based on Lewy body pathology. Most of the confirmed genetic risks for PD show heterogenous neuropathology, even within kindreds, which may or may not include Lewy body pathology. We review the literature of genetic PD autopsies from cases with molecularly confirmed PD or parkinsonism and summarize main findings on SNCA (n = 25), Parkin (n = 20, 17 bi-allelic and 3 heterozygotes), PINK1 (n = 5, 1 bi-allelic and 4 heterozygotes), DJ-1 (n = 1), LRRK2 (n = 55), GBA (n = 10 Gaucher disease patients with parkinsonism), DNAJC13, GCH1, ATP13A2, PLA2G6 (n = 8 patients, 2 with PD), MPAN (n = 2), FBXO7, RAB39B, and ATXN2 (SCA2), as well as on 22q deletion syndrome (n = 3). Findings from autopsies of heterozygous mutation carriers of genes that are traditionally considered recessively inherited are also discussed. Lewy bodies may be present in syndromes clinically distinctive from PD (eg, MPAN-related neurodegeneration) and absent in patients with clinical PD syndrome (eg, LRRK2-PD or Parkin-PD). Therefore, the authors can conclude that the presence of Lewy bodies are not specific to the diagnosis of PD and that PD can be diagnosed even in the absence of Lewy body pathology. Interventions that reduce alpha-synuclein load may be more justified in SNCA-PD or GBA-PD than in other genetic forms of PD. The number of reported genetic PD autopsies remains small, and there are limited genotype-clinical-pathological-phenotype studies. Therefore, larger series of autopsies from genetic PD patients are required. © 2017 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Humans; Parkinsonian Disorders

Kufor-Rakeb syndrome (KRS) is an autosomal recessive form of Parkinson's disease (PD) with juvenile onset of parkinsonism, often accompanied by extra clinical features such as supranuclear gaze palsy, dementia and generalised brain atrophy. Mutations in ATP13A2, associated with the PARK9 locus (chromosome 1p36) have been identified in KRS patients. ATP13A2 encodes a lysosomal P5B-type ATPase which has functional domains similar to other P-type ATPases which mainly transport cations. Consistently, recent studies suggest that human ATP13A2 may preferably regulate Zn2+, while ATP13A2 from other species have different substrate selectivity. Until now, fourteen mutations in ATP13A2 have been associated with KRS, while other mutations have been reported in association with neuronal ceroid lipofuscinosis (NCL) and early-onset PD. Experimentally, these disease- associated ATP13A2 mutations have been shown to confer loss-of-function to the protein by disrupting its protein structure and function to varying degrees, ranging from impairment in ATPase function to total loss of protein, confirming their pathogenicity. Loss of functional ATP13A2 has been shown to induce Zn2+ dyshomeostasis. Disturbances in Zn2+ homeostasis impair mitochondrial and lysosomal function which leads to loss of mitochondrial bioenergetic capacity and accumulation of lysosomal substrates such as α-synuclein and lipofuscin. Additionally, ATP13A2 appears to be involved in α-synuclein externalisation through its Zn2+-regulating activity. In this review, we will discuss all the reported KRS/NCL-associated ATP13A2 mutations along with several PD-associated mutations which have been experimentally assessed, in respect to their impact on the protein structure and function of ATP13A2.

Topics: Adolescent; Age of Onset; alpha-Synuclein; Cations, Divalent; Gene Expression; Genes, Recessive; Humans; Ion Transport; Lipofuscin; Lysosomes; Mitochondria; Mutation; Neuronal Ceroid-Lipofuscinoses; Parkinsonian Disorders; Protein Domains; Proton-Translocating ATPases; Structure-Activity Relationship; Zinc

As a key regulator of cell metabolism and survival, mechanistic target of rapamycin (mTOR) emerges as a novel therapeutic target for Parkinson's disease (PD). A growing body of research indicates that restoring perturbed mTOR signaling in PD models can prevent neuronal cell death. Nevertheless, molecular mechanisms underlying mTOR-mediated effects in PD have not been fully understood yet. Here, we review recent progress in characterizing the association of mTOR signaling with PD risk factors and further discuss the potential roles of mTOR in PD.

Topics: alpha-Synuclein; Animals; Apoptosis; Autophagy; Dopaminergic Neurons; Genetic Predisposition to Disease; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Nerve Tissue Proteins; Neurotoxins; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Risk Factors; Signal Transduction; TOR Serine-Threonine Kinases

The identification of the p.A53T mutation in the SNCA gene encoding alpha-synuclein (alpha-syn), as causative of autosomal dominant Parkinson disease (PD) represented a fundamental milestone, which paved the way to the extremely prolific field of PD genetics. Despite being the oldest player in this field and only a rare cause of inherited PD, research on alpha-syn has remained incredibly active over nearly twenty decades, leading to identify alpha-syn aggregation as a key mechanism in PD pathogenesis. The past two years have witnessed new exciting findings, with the discovery of at least three novel pathogenic mutations (p.H50Q, p.G51D and p.A53E) causative of complex parkinsonian phenotypes, and the identification of additional patients carrying "old" SNCA mutations (p.A53T, p.A30P, p.E46K and whole gene multiplications), which has allowed to further expand their phenotypic spectrum. This review aims at providing a clinical and functional update on the most recent findings in alpha-syn genetics, at the same time discussing novel avenues of SNCA research such as those on somatic mutations and epigenetic mechanisms.

Topics: alpha-Synuclein; Animals; Humans; Mutation; Parkinsonian Disorders; Phenotype

The discovery in 1997 that mutations in the SNCA gene cause Parkinson's disease (PD) greatly advanced our understanding of this illness. There are pathogenic missense mutations and multiplication mutations in SNCA. Thus, not only a mutant protein, but also an increased dose of wild-type protein can produce autosomal dominant parkinsonism. We review the literature on SNCA duplications and focus on pathologically-confirmed cases. We also report a newly-identified American family with SNCA duplication whose proband was autopsied. We found that over half of the reported cases with SNCA duplication had early-onset parkinsonism and non-motor features, such as dysautonomia, rapid eye movement sleep behavior disorder (RBD), hallucinations (usually visual) and cognitive deficits leading to dementia. Only a few cases have presented with typical features of PD. Our case presented with depression and RBD that preceded parkinsonism, and dysautonomia that led to an initial diagnosis of multiple system atrophy. Dementia and visual hallucinations followed. Our patient and the other reported cases with SNCA duplications had widespread cortical Lewy pathology. Neuronal loss in the hippocampal cornu ammonis 2/3 regions were seen in about half of the autopsied SNCA duplication cases. Similar pathology was also observed in SNCA missense mutation and triplication carriers.

Topics: Adult; alpha-Synuclein; Gene Duplication; Humans; Male; Mutation, Missense; Parkinsonian Disorders; Pedigree

The groundbreaking discovery of mutations in the SNCA gene in a rare familial form of Parkinson's disease (PD) has revolutionized our basic understanding of the etiology of PD and other related disorders. Genome-wide Association Studies has demonstrated a wide array of single-nucleotide polymorphisms associated with the increasing risk of developing the more common type, sporadic PD, further corroborating the genetic etiology of PD. Among them, SNCA is a gene responsible for encoding α-synuclein, a protein found to be the major component of Lewy body and Lewy neurite, both of these components are the pathognomonic hallmarks of PD. Thus, it has been postulated that this gene plays specific roles in pathogenesis of PD. Here, we summarize the basic biological characteristics of the wild type of the protein (wt-α-synuclein) as well as genetic and epigenetic features of its encoding gene (SNCA) in PD. Based on these characteristics, SNCA may be involved in PD pathogenesis in at least 2 ways: wt-α-synuclein overexpression and its mutation types via different mechanisms. Associations between SNCA mutations and other Lewy body disorders, such as dementia with Lewy bodies and multiple system atrophy, are also mentioned. Finally, it is necessary to explore the influences which SNCA exerts on clinical and neuropathological phenotypes by promoting the transfer of scientific research into practice, such as clinical evaluation, diagnosis, and treatment of the disease. We believe it is promising to target SNCA for developing novel therapeutic strategies for parkinsonism.

Topics: alpha-Synuclein; Epigenesis, Genetic; Gene Expression; Genome-Wide Association Study; Humans; Lewy Bodies; Molecular Targeted Therapy; Mutation; Parkinsonian Disorders; Polymorphism, Single Nucleotide; Risk

Gaucher disease is associated with Parkinson's disease (PD) by mutations in glucocerebrosidase (GCase). The gene encoding GCase, glucosidase beta acid (GBA), is an important risk factor for PD. Findings from large studies have shown that patients with PD have an increased frequency of mutations in GBA and that GBA mutation carriers exhibit diverse parkinsonian phenotypes and Lewy body pathology. Although the mechanism for this association remains elusive, some hypotheses have been proposed to explain it, including gain of function caused by GBA mutations, which increases α-synuclein (α-syn) aggregation, loss of function due to lysosomal enzyme deficiency, which affects α-syn clearance, and even a bidirectional feedback loop, but each of these hypotheses has its limitations. It is also worth noting that many findings have implicated the interaction between α-syn and GCase, indicating the essential role of the interaction in the pathogenesis of GBA-associated parkinsonism. Therefore, the current review focuses on α-syn and GCase, and it provides some new thoughts that may be helpful for understanding the α-syn-GCase interaction and unraveling the exact mechanism underlying GBA-associated parkinsonism.

Topics: alpha-Synuclein; Animals; Epistasis, Genetic; Gaucher Disease; Glucosylceramidase; Heterozygote; Humans; Mutation; Parkinsonian Disorders

Parkinson's Disease (PD) and alpha synucleinopathies are multifactorial disorders, which manifest through motor symptoms and non-motor symptoms involving the Central Nervous System (CNS), the Peripheral Nervous System (PNS) and, recently, also the Enteric Nervous System (ENS). The typical hallmarks of alpha synucleinopathies are proteinaceous inclusions of alpha synuclein (αS). In PD they are known as Lewy Bodies (LBs) and Lewy Neurites (LNs), discovered in dopaminergic neurons of substantia nigra (pars compacta) as well as in other regions of the central and peripheral nervous systems. Despite the clear causes which lead to LBs/LNs are still unknown, according to Braak's theory, these inclusions appear first in PNS to spread, following neuronal innervation, towards the CNS in a spatio- temporal dissemination described in a staging procedure. In line with these observations, several animal models have been used with the purpose to reproduce PD as well as to propose new therapeutic approaches. Different pathways can cooperate to neurodegeneration in PD such as genetic mutations of αS gene, mitochondrial dysfunctions, neuroinflammation. The present review highlights αS as the key-word for PD pathology and alpha synucleinopathies and a main target in PD research. Several therapeutic approaches can be proposed, however all of them are addressed in advanced stages of the pathology. Our focus will be the alteration of αS physiological pathway, which allows to address therapy in early stages at intracellular or extracellular level, such as the use of anti ER-stress compounds and innovative immunotherapy, which could be promising tools to reduce neuronal degeneration and to halt PD progression.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Biomarkers; Disease Progression; Dopaminergic Neurons; Early Diagnosis; Gastrointestinal Diseases; Humans; Immunotherapy; Lewy Bodies; Lewy Body Disease; Mice; Mice, Transgenic; Mitochondria; Models, Neurological; Molecular Targeted Therapy; Neuroglia; Organ Specificity; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Protein Structure, Tertiary; Rats; Single-Chain Antibodies; Unfolded Protein Response; Vagus Nerve

In the past few years, there have been a large number of genes identified that contribute to the lifetime risk of Parkinson's disease (PD). Some genes follow a Mendelian inheritance pattern, but others are risk factors for apparently sporadic PD. Here, we will focus on those genes nominated by genome-wide association studies (GWAS) in sporadic PD, with a particular emphasis on genes that overlap between familial and sporadic disease such as those encoding a-synuclein (SNCA), tau (MAPT), and leucine-rich repeat kinase 2 (LRRK2). We will advance the view that there are likely relationships between these genes that map not only to neuronal processes, but also to neuroinflammation. We will particularly discuss evidence for a role of PD proteins in microglial activation and regulation of the autophagy-lysosome system that is dependent on microtubule transport in neurons. Thus, there are at least two non-mutually exclusive pathways that include both non-cell-autonomous and cell-autonomous mechanisms in the PD brain. Collectively, these data have highlighted the amount of progress made in understanding PD and suggest ways forward to further dissect this disorder.

Topics: alpha-Synuclein; Animals; Autonomic Pathways; Genome-Wide Association Study; Humans; Inflammation; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Metabolic Networks and Pathways; Parkinson Disease; Parkinsonian Disorders; Protein Serine-Threonine Kinases; tau Proteins

There is still an open debate whether multiple sclerosis (MS) lesions can cause parkinsonian symptoms, or the coexistence of both diseases in the same patient is accidental. Moreover, α-synuclein (α Syn), the hallmark of Parkinson's disease (PD) seems also to play a crucial role in MS. So far, 42 cases of co-occurrence of parkinsonism and MS have been reported, but CSF α Syn measurement is lacking. To our knowledge, we report the first case with concomitant MS and PD diagnosis based on both clinico-radiological and CSF α Syn findings and review of literature.

Topics: alpha-Synuclein; Brain; Diagnosis, Differential; Female; Humans; Middle Aged; Multiple Sclerosis; Parkinson Disease; Parkinsonian Disorders; Treatment Outcome

Accumulation of α-synuclein (α-syn) leading to the formation of insoluble intracellular aggregates named Lewy bodies is proposed to have a significant role in Parkinson's disease (PD) pathology. Nonhuman primate (NHP) models of PD have proven essential for understanding the neurobiological basis of the disease and for the preclinical evaluation of first-in-class and invasive therapies. In addition to neurotoxin, aging and intracerebral gene transfer models, a new generation of models using inoculations of α-syn formulations, as well as transgenic methods is emerging. Understanding of their advantages and limitations will be essential when choosing a platform to evaluate α-syn-related pathology and interpreting the test results of new treatments targeting α-syn aggregation. In this review we aim to provide insight on this issue by critically analyzing the differences in endogenous α-syn, as well as α-syn pathology in PD and PD NHP models.

Topics: alpha-Synuclein; Animals; Brain; Humans; Parkinsonian Disorders; Primates

Parkinson's disease (PD) is associated with several non-motor symptoms, such as behavioral changes, urinary dysfunction, sleep disorders, fatigue and, above all, gastrointestinal (GI) dysfunction, including gastric dysmotility, constipation and anorectal dysfunction. Delayed gastric emptying, progressing to gastroparesis, is reported in up to 100% of patients with PD, and it occurs at all stages of the disease with severe consequences to the patient's quality of life. The presence of α-synuclein (α-syn) aggregates in myenteric neurons throughout the digestive tract, as well as morpho-functional alterations of the enteric nervous system (ENS), have been documented in PD. In particular, gastric dysmotility in PD has been associated with an impairment of the brain-gut axis, involving the efferent fibers of the vagal pathway projecting directly to the gastric myenteric plexus. The present review intends to provide an integrated overview of available knowledge on the possible role played by the ENS, considered as a semi-autonomous nervous network, in the pathophysiology of gastric dysmotility in PD. Particular attention has been paid review how translational evidence in humans and studies in pre-clinical models are allowing a better understanding of the functional, neurochemical and molecular alterations likely underlying gastric motor abnormalities occurring in PD.

Topics: alpha-Synuclein; Animals; Cholecystokinin; Efferent Pathways; Enteric Nervous System; Gastric Emptying; Gastrointestinal Motility; Gastroparesis; Humans; Mice; Mice, Transgenic; Models, Neurological; Neuromuscular Junction; Oxidopamine; Parkinson Disease; Parkinsonian Disorders; Protein Aggregates; Rats; Rotenone; Translational Research, Biomedical; Vagus Nerve

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

The studies presented in this review attempt to describe the operative properties of the genes involved in generation of early and late onset of Parkinson's disease or Parkinson-like disorders and how mutation in these genes relate to onset of manganism. These include the genes α-synuclein, parkin, PINK1, DJ-1, ATP13A2, and SLC30A10 which are associated with early-onset of Parkinson's as well as those genes linked with late onset of the disorder which include, LRRK2 and VPS35. Since mutations in these genes and excess Mn potentially disrupt similar cellular processes within the basal ganglia, it is reasonable to hypothesize that the expressed symptoms of Parkinson's disease may overlap with that of manganese (Mn) toxicity. There appears to be four common processes linking the two disorders, as mutations in genes associated with Parkinsonism initiate similar adverse biological reactions acknowledged to stimulate Mn-induced dopaminergic cell death including; (1) disruption of mitochondrial function leading to oxidative stress, (2) abnormalities in vesicle processing, (3) altered proteasomal and lysosomal protein degradation, and (4) α-synuclein aggregation The mutual neurotoxic processes provoked by mutations in these genes in concert with the biological disturbances produced by Mn, most likely, act in synchrony to contribute to the severity, characteristics and onset of both disorders.

Topics: alpha-Synuclein; Animals; Cation Transport Proteins; Environmental Exposure; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Manganese; Mice; Mutation; Oncogene Proteins; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Proton-Translocating ATPases; Risk Factors; Signal Transduction; Ubiquitin-Protein Ligases; Vesicular Transport Proteins; Zinc Transporter 8

In 2013, European MSA Study Group demonstrated the prospective natural history of MSA. This study was greatly useful for better patients' management and future development of disease-modifying therapy. Although the diagnosis of early symptomatic stage is also an important factor for successful outcome of disease-modifying therapy, current diagnostic criteria for MSA, which has focused on the combination of motor and autonomic manifestations cannot diagnose MSA patients showing isolated autonomic failure in the early course of illness. We presented four premotor MSA patients who had sudden death prior to fulfilling the diagnostic criteria. 4 cases had very mild OPC and SN pathology, but significant autonomic system involvement including the intermediolateral nucleus, Onuf's nucleus, and medullary autonomic nucleus. Contrary, Petrovic et al reported four pathologically proven MSA patients with disease duration of 15 years or more. All patients presented isolated parkinsonism for a long time and mean duration from onset to dysautonomia was 9 years. Novel diagnostic biomarkers, which have a potential for evaluation of the component of glial cytoplasmic inclusion such as alpha-synuclein radiotracer and serum and CSF alpha-synuclein levels may be a key way to support the diagnosis of patients at the stage of "mono system atrophy".

Topics: alpha-Synuclein; Biomarkers; Death, Sudden; Ghrelin; Humans; Multiple System Atrophy; Parkinsonian Disorders; Time Factors

Progressive supranuclear palsy (PSP) is the most common atypical parkinsonian syndrome comprising two main clinical subtypes: Richardson's syndrome (RS), characterized by prominent postural instability, supranuclear vertical gaze palsy and frontal dysfunction; and PSP-parkinsonism (PSP-P) which is characterized by an asymmetric onset, tremor and moderate initial therapeutic response to levodopa. The early clinical features of PSP-P are often difficult to discern from idiopathic Parkinson's disease (PD), and other atypical parkinsonian disorders, including multiple system atrophy (MSA) and corticobasal syndrome (CBS). In addition, rare PSP subtypes may be overlooked or misdiagnosed if there are atypical features present. The differentiation between atypical parkinsonian disorders and PD is important because the prognoses are different, and there are different responses to therapy. Structural and functional imaging, although currently of limited diagnostic value for individual use in early disease, may contribute valuable information in the differential diagnosis of PSP. A growing body of evidence shows the importance of CSF biomarkers in distinguishing between atypical parkinsonian disorders particularly early in their course when disease-modifying therapies are becoming available. However, specific diagnostic CSF biomarkers have yet to be identified. In the absence of reliable disease-specific markers, we provide an update of the recent literature on the assessment of clinical symptoms, pathology, neuroimaging and biofluid markers that might help to distinguish between these overlapping conditions early in the course of the disease.

Topics: Age of Onset; alpha-Synuclein; Biomarkers; Brain; Gait Disorders, Neurologic; Humans; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Multiple System Atrophy; Neuroimaging; Parkinsonian Disorders; Positron-Emission Tomography; Prognosis; Supranuclear Palsy, Progressive; Symptom Assessment; tau Proteins; Ultrasonography, Doppler, Transcranial

Mutations in the ß-glucocerebrosidase gene (GBA), which encodes the lysosomal enzyme ß-glucocerebrosidase, have traditionally been implicated in Gaucher disease, an autosomal recessive lysosomal storage disorder. Yet the past two decades have yielded an explosion of epidemiological and basic-science evidence linking mutations in GBA with the development of Parkinson disease (PD) as well. Although the specific contribution of mutant GBA to the pathogenesis of parkinsonism remains unknown, evidence suggests that both loss of function and toxic gain of function by abnormal ß-glucocerebrosidase may be important, and implicates a close relationship between ß-glucocerebrosidase and α-synuclein. Furthermore, multiple lines of evidence suggest that although GBA-associated PD closely mimics idiopathic PD (IPD), it may present at a younger age, and is more frequently complicated by cognitive dysfunction. Understanding the clinical association between GBA and PD, and the relationship between ß-glucocerebrosidase and α-synuclein, may enhance understanding of the pathogenesis of IPD, improve prognostication and treatment of GBA carriers with parkinsonism, and furthermore inform therapies for IPD not due to GBA mutations.

Topics: alpha-Synuclein; Endophenotypes; Gaucher Disease; Genetic Counseling; Genetic Predisposition to Disease; Glucosylceramidase; Humans; Molecular Targeted Therapy; Mutation; Neuroimaging; Parkinsonian Disorders

Parkinson's disease (PD) is one of the most common degenerative disorders of the central nervous system that produces motor and non-motor symptoms. The majority of cases are idiopathic and characterized by the presence of Lewy bodies containing fibrillar α-synuclein. Small ubiquitin-related modifier (SUMO) immunoreactivity was observed among others in cases with PD. Key disease-associated proteins are SUMO-modified, linking this posttranslational modification to neurodegeneration. SUMOylation and SUMO-mediated mechanisms have been intensively studied in recent years, revealing nuclear and extranuclear functions for SUMO in a variety of cellular processes, including the regulation of transcriptional activity, modulation of signal transduction pathways, and response to cellular stress. This points to a role for SUMO more than just an antagonist to ubiquitin and proteasomal degradation. The identification of risk and age-at-onset gene loci was a breakthrough in PD and promoted the understanding of molecular mechanisms in the pathology. PD has been increasingly linked with mitochondrial dysfunction and impaired mitochondrial quality control. Interestingly, SUMO is involved in many of these processes and up-regulated in response to cellular stress, further emphasizing the importance of SUMOylation in physiology and disease.

Topics: alpha-Synuclein; Dopaminergic Neurons; Gene Expression Regulation; Humans; Intracellular Signaling Peptides and Proteins; Mitochondria; Nerve Tissue Proteins; Neurotoxins; Oncogene Proteins; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Protein Binding; Protein Deglycase DJ-1; Signal Transduction; Small Ubiquitin-Related Modifier Proteins; Sumoylation; Transcription, Genetic; Ubiquitin; Ubiquitin-Protein Ligase Complexes; Ubiquitin-Protein Ligases

Although α-synuclein protein (αS) aggregates from a monomer to assemblies such as oligomer, protofibril and mature fibril, the early intermediate aggregate, that is, oligomer has been considered to be most toxic species in recent reports. While it was reported that αS concentration in cerebrospinal fluid was decreased significantly in the patients with Parkinson's disease (PD) and dementia with Lewy bodies, there were reports that αS oligomer concentration was elevated in cerebrospinal fluid of PD patients. Moreover, it was supposed that αS oligomer concentration was also elevated in blood of PD patients. Further studies of αS in cerebrospinal fluid and blood would lead to establishment of the significance of αS as a biomarker for α-synucleinopathies including PD.

Topics: alpha-Synuclein; Biomarkers; Early Diagnosis; Humans; Lewy Body Disease; Parkinsonian Disorders; Protein Aggregates; Protein Aggregation, Pathological

Research in movement disorders in 2012 has improved our understanding of the pathogenic mechanisms of disease and led to development of potential novel therapeutic approaches. Key advances were linked to mechanisms underlying spread of neurodegenerative pathology, immunotherapy, stem cells, genetics and deep brain stimulation in parkinsonism and related disorders.

Topics: alpha-Synuclein; Animals; Deep Brain Stimulation; Humans; Immunotherapy; Mice; Mice, Transgenic; Movement Disorders; Neurodegenerative Diseases; Neuroimaging; Parkinsonian Disorders; Pluripotent Stem Cells; Stem Cell Transplantation

Recently, several genes for parkinsonism have been identified. Among them, familial Parkinson's disease (PD) could be assigned for PARK disorders. PARK disorders consist of three different inherited modes such as autosomal recessive, autosomal dominant modes and susceptible genes. Some of them manifest not only typical parkinsonism, but also dystonia, pyramidal sign, and mental dysfunctions. While the monogenic forms of PARK disorders have been reviewed extensively, it is not easy to do differential diagnosis of PARK disorders due to the additional features except for typical parkinsonism. In this presentation, we focus on two different scenarios of patients with autosomal dominant parkinsonism: (1) parkinsonism with mutations in one of the PARK genes; (2) parkinsonism with mutations other than PARK genes or yet other genes where parkinsonism is a well recognized, concomitant, or even an isolated feature.

Topics: alpha-Synuclein; Animals; Diagnosis, Differential; Genetic Predisposition to Disease; Humans; Mutation; Parkinsonian Disorders

Major progress in genetic studies of Parkinson's disease (PD) and parkinsonism has been achieved in the last two decades.. We provide a brief review of the current status of PARK and non-PARK loci/genes, and discuss two new genes: eIF4G1 and VPS35.. The literature on PARK and non-PARK loci/genes was reviewed and some novel information on two new genes is provided.. There are 18 PARK loci. The symptomatic carriers of these genes usually present with parkinsonism, although additional clinical features can be seen during the course of the disease. Carriers of non-PARK loci/genes frequently present with a mixed phenotype that includes parkinsonism and additional clinical features. Carriers of the eIF4G1 and VPS35 genes present with a parkinsonian phenotype. The pathology of eIF4G1 is of the α-synuclein type; the pathology of VPS35 is unknown.. The current genetic classification of PD/parkinsonism genes is not ideal. The pathological classification based on the accumulation of particular proteins/inclusions is also misleading since there are kindred with a single mutation but pleomorphic pathology. A better classification of neurodegenerative conditions is needed. It is hoped that the genetic studies will lead to better therapies.

Topics: alpha-Synuclein; Eukaryotic Initiation Factor-4G; Genetic Predisposition to Disease; Humans; Mutation; Parkinsonian Disorders; Vesicular Transport Proteins

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

Atypical parkinsonian disorders (APDs) comprise a heterogenous group of disorders including multiple system atrophy (MSA), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Based on literature published in 2010, we here review recent advances in the APD field.. Genome-wide association studies have provided robust evidence of increased disease risk conferred by synuclein and tau gene variants in MSA and PSP. Furthermore, advanced imaging tools have been established in the differential diagnosis and as surrogate markers of disease activity in patients with APDs. Finally, although therapeutic options are still disappointing, translational research into disease-modifying strategies has accelerated with the increasing availability of transgenic animal models, particularly for MSA.. Remarkable progress has been achieved in the field of APDs, and advances in the genetics, molecular biology and neuroimaging of these disorders will continue to facilitate intensified clinical trial activity.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Clinical Trials as Topic; Diagnosis, Differential; Genome-Wide Association Study; Humans; Lewy Body Disease; Multiple System Atrophy; Parkinsonian Disorders; Supranuclear Palsy, Progressive; tau Proteins

Clinical, genetic and pathological studies demonstrate that mutations in glucocerebrosidase (GBA), which encodes the lysosomal enzyme deficient in Gaucher disease (GD), are risk factors for Parkinson disease (PD) and related disorders. Some patients with GD and Gaucher carriers develop parkinsonism. Furthermore, subjects with PD have an increased frequency of GBA mutations. GBA-mutation carriers exhibit diverse parkinsonian phenotypes and have glucocerebrosidase-positive Lewy bodies. Although the mechanism for this association is unknown, we present several theories, including protein aggregation, prion transmission, lipid accumulation and impaired autophagy, mitophagy or trafficking. Each model has inherent limitations, and a second-hit mutation might be essential. Elucidation of the basis for this link will have important consequences for studying these diseases and should provide insights into lysosomal pathways and potential treatment strategies.

Topics: alpha-Synuclein; Autophagy; Endoplasmic Reticulum-Associated Degradation; Gaucher Disease; Glucosylceramidase; Humans; Lewy Bodies; Lipid Metabolism; Lysosomes; Mutation; Parkinsonian Disorders; Prions

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

Topics: Adolescent; Age of Onset; alpha-Synuclein; Child; Humans; Intracellular Signaling Peptides and Proteins; Oncogene Proteins; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Receptors, Dopamine D5; Tremor; Ubiquitin-Protein Ligases

Parkinson's disease is the second most common neurodegenerative disorder and remains incurable. Considerable progress has been made in understanding the molecular mechanisms of this disease, in particular, a distinct set of genes have emerged, whose dysfunctional regulation is strongly associated with the condition. These genes include alpha-synuclein, parkin, PTEN induced Putative Kinase 1 (PINK1), DJ-1, Leucine Rich Repeat Kinase 2 (LRRK2) and ATP13A2. Here we discuss what has been learnt in the study of these genes and how these genes may contribute to the pathogenesis of Parkinson's disease through different molecular pathways, and consider how these pathways might converge to lead to the onset of Parkinson's disease.

Topics: alpha-Synuclein; Genes, Dominant; Genes, Recessive; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Parkinson Disease; Parkinsonian Disorders; Protein Kinases; Protein Serine-Threonine Kinases; Proton-Translocating ATPases; Ubiquitin-Protein Ligases

Over the last few years, genetic findings have changed our views on Parkinson's disease (PD), as mutations in a growing number of genes are found to cause monogenic forms of the disorder. Point mutations in the gene for alpha-synuclein, as well as duplications and triplications of the wild-type gene cause a dominant form of PD in rare families, pointing towards mishandling of this protein as a crucial step in the molecular pathogenesis of the disorder. Mutations in the gene for leucine-rich repeat kinase 2 (LRRK2) have recently been identified as a much more common cause for dominant PD, while mutations in the parkin gene, in DJ-1, PINK1 and ATP13A2 all cause autosomal-recessive parkinsonism of early onset. Mutations in recessive genes probably are pathogenic through loss-of-function mechanisms, suggesting that their wild-type products protect dopaminergic cells against a variety of insults. Evidence is emerging that at least some of these genes may play a direct role in the etiology of the common sporadic form of PD. Further, it is likely that the cellular pathways identified in rare monogenic variants of the disease also shed light on the molecular pathogenesis in typical sporadic PD.

Topics: alpha-Synuclein; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Oncogene Proteins; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Ubiquitin-Protein Ligases

The proteinopathy sporadic Parkinson's disease (sPD) is the second most frequent degenerative disorder of the human nervous system after Alzheimer's disease. The alpha-synuclein inclusion body pathology (Lewy pathology) associated with sPD is distributed throughout the central, peripheral, and enteric nervous systems. The resulting nonrandom neuronal dysfunction and, in some regions, neuronal loss is reflected in a topographic distribution pattern of the Lewy pathology that, in the brain, can be staged. Except for olfactory structures and spinal cord constituents of the pain system, sensory components of the nervous system remain uninvolved or virtually intact. The most disease-related damage revolves around motor areas--particularly around superordinate centers of the limbic and visceromotor systems as well as portions of the somatomotor system. Vulnerable regions are interconnected anatomically and susceptible nerve cell types are not neurotransmitter-dependent. Not all clinical symptoms emerging in the course of sPD can be explained by a lack of dopamine in the nigrostriatal system. These include autonomic dysfunction, pain, hyposmia or anosmia, excessive daytime sleepiness, rapid eye movement (REM) sleep behavioral disorder, depression, anxiety, cognitive decline, and dementia. Against the background of the normal morphology and anatomy, the authors analyze the pathoanatomy of sPD in the nervous system at various neuropathological stages and summarize the potential functional consequences of the lesions.

Topics: alpha-Synuclein; Humans; Nervous System; Parkinsonian Disorders; Protein Folding

A body of work has emerged over the past decade demonstrating a relationship between mutations in glucocerebrosidase gene (GBA), the gene implicated in Gaucher disease (GD), and the development of parkinsonism. Several different lines of research support this relationship. First, patients with GD who are homozygous for mutations in GBA have a higher than expected propensity to develop Parkinson's disease (PD). Furthermore, carriers of GBA mutations, particularly family members of patients with GD, have displayed an increased rate of parkinsonism. Subsequently, investigators from centers around the world screened cohorts of patients with parkinsonism for GBA mutations and found that overall, subjects with PD, as well as other Lewy body disorders, have at least a fivefold increase in the number of carriers of GBA mutations as compared to age-matched controls. In addition, neuropathologic studies of subjects with parkinsonism carrying GBA mutations demonstrate Lewy bodies, depletion of neurons of the substantia nigra, and involvement of hippocampal layers CA2-4. Although the basis for this association has yet to be elucidated, evidence continues to support the role of GBA as a PD risk factor across different centers, synucleinopathies, and ethnicities. Further studies of the association between GD and parkinsonism will stimulate new insights into the pathophysiology of the two disorders and will prove crucial for both genetic counseling of patients and family members and the design of relevant therapeutic strategies for specific patients with parkinsonism.

Topics: Adult; Aged; alpha-Synuclein; Child; DNA Mutational Analysis; Enzyme Replacement Therapy; Ethnicity; Female; Gaucher Disease; Genetic Counseling; Genetic Predisposition to Disease; Glucosylceramidase; Hippocampus; Humans; Lewy Body Disease; Lysosomes; Male; Middle Aged; Mutation; Parkinsonian Disorders; Risk Factors; Substantia Nigra

Parkinson's disease is a common progressive bradykinetic disorder that can be accurately diagnosed. It is characterised by the presence of severe pars-compacta nigral-cell loss, and accumulation of aggregated alpha-synuclein in specific brain stem, spinal cord, and cortical regions. The main known risk factor is age. Susceptibility genes including alpha-synuclein, leucine rich repeat kinase 2 (LRRK-2), and glucocerebrosidase (GBA) have shown that genetic predisposition is another important causal factor. Dopamine replacement therapy considerably reduces motor handicap, and effective treatment of associated depression, pain, constipation, and nocturnal difficulties can improve quality of life. Embryonic stem cells and gene therapy are promising research therapeutic approaches.

Topics: Age Distribution; Age of Onset; Aged; alpha-Synuclein; Cause of Death; Dopamine Agents; Embryonic Stem Cells; Female; Genetic Predisposition to Disease; Genetic Therapy; Glucosylceramidase; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Mutation; Parkinson Disease; Parkinsonian Disorders; Protein Serine-Threonine Kinases; Risk Factors; Sex Distribution

The aggregation of numerous peptides or proteins has been linked to the onset of disease, including Abeta (amyloid beta-peptide) in AD (Alzheimer's disease), asyn (alpha-synuclein) in Parkinson's disease and amylin in Type 2 diabetes. Diverse amyloidogenic proteins can often be cut down to an SRE (self-recognition element) of as few as five residues that retains the ability to aggregate. SREs can be used as a starting point for aggregation inhibitors. In particular, N-methylated SREs can bind to a target on one side, but have hydrogen-bonding blocked on their methylated face, interfering with further assembly. We applied this strategy to develop Abeta toxicity inhibitors. Our compounds, and a range of compounds from the literature, were compared under the same conditions, using biophysical and toxicity assays. Two N-methylated D-peptide inhibitors with unnatural side chains were the most effective and can reverse Abeta-induced inhibition of LTP (long-term potentiation) at concentrations as low as 10 nM. An SRE in asyn (VAQKTV) was identified using solid-state NMR. When VAQKTV was N-methylated, it was able to disrupt asyn aggregation. N-methylated derivatives of the SRE of amylin are also able to inhibit amylin aggregation.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Drug Design; Humans; Magnetic Resonance Spectroscopy; Molecular Structure; Parkinsonian Disorders; Peptide Fragments; Peptides; Protein Folding

Parkinson disease (PD), is a movement disorder pathologically characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Although the inherited forms of PD account for only 5 to 10% of PD cases, the identification of gene mutations in the genes implicated in familial PD in the past 10 years, including the findings regarding the a-synuclein, Parkin, ubiquitin-C-terminal hydrolase-L1 (UCH-L1), PINK1, DJ-1 and the ATP13A2 genes, has advanced understanding of the molecular mechanisms in each case of genetic PD. Most familial forms of PD develop at an early onset. However, recent identification of the leucine-rich repeat kinase (LRRK) 2 gene for a late-onset PD, the clinicopathological feature of which closely resembles that of sporadic PD, is expected to enable the clarification of the underlying causes of general PD. Recent studies on the physiological and pathological functions of these identified gene products have revealed overlapping pathogenetic pathways. The common features of these aberrant pathways are impaired protein degradation/quality control, mitochondrial dysfunction, and altered vesicle transport. Several attempts have been made towards developing molecular-targeted therapies directed against mitochondria (e.g., antioxidants, permeability transition pore modulators, and mitochondrial biogenesis stimulators), protein quality control and vesicle transport (e.g., gene silencing, immunization of asynuclein, and protofibril-destabilizing reagents). To ensure the successful implementation of such strategies, it is important to understand the events occuring at an early stage of PD. Further, studies using mammalian PD models for pharmacological analysis combined with studies employing lower organisms for genetic analyses such as worm, fly, and yeast will be helpful to determine effective prevention and treatment strategies for PD, which will replace the conventional symptomatic treatments for PD.

Topics: alpha-Synuclein; Animals; Gene Targeting; Genetic Therapy; High-Temperature Requirement A Serine Peptidase 2; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mitochondria; Mitochondrial Proteins; Oncogene Proteins; Oxidative Stress; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Serine Endopeptidases; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases

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

The identification of the first gene in familial Parkinson's disease (PD) only 10 years ago was a major step in the understanding of the molecular mechanisms in neurodegeneration. Alpha-synuclein aggregation was not only recognized as a key event in neurodegeneration in patients carrying mutations in this gene, but it turned out to be the most consistent marker to define Lewy body pathology also in non-heritable idiopathic PD (IPD). Subsequent comprehensive pathoanatomical studies of IPD brains led to a novel concept of an ascending pathological process in variable stages that are reflected by alpha-synuclein aggregation at specific predilection sites. To date, more than seven genes are known to cause familial PD. The fact that these genetic forms of Parkinsonism present with clinical features indistinguishable from IPD, but may display neuropathological features that are not consistent with IPD, underscores the need of a more differentiated approach to familial and sporadic forms of Parkinsonism. Indeed, in distinct populations, mutations in one single gene were found to cause the disease in up to 40% of patients formerly described as 'idiopathic' cases. These findings indicate that IPD, as defined by a late-onset disorder with no (apparent) genetic contribution, is part of a clinical syndrome that becomes more and more heterogeneous in terms of aetiology, with overlapping clinical and pathoanatomical features. Thus in the present review, we discuss clues from familial PD to our understanding of the molecular pathogenesis of neurodegeneration with special consideration of the variable clinical and neuropathological aspects.

Topics: alpha-Synuclein; Brain; Genetic Predisposition to Disease; Humans; Parkinsonian Disorders; Phenotype

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

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by selective loss of dopaminergic neurons and the presence of Lewy bodies. The pathogenesis of PD remains incompletely understood. Environmental factors, oxidative damage, misfolded protein aggregates, ubiquitin-proteasome system impairment, and mitochondrial dysfunction might all be involved. Recent studies point to activation of endoplasmic reticulum (ER) stress-mediated cell death linked to PD. Accumulation of unfolded and/or misfolded proteins in the ER lumen induces ER stress. To withstand such potentially lethal conditions, intracellular signaling pathways collectively termed the unfolded protein responses (UPR) are activated. The UPR include translational attenuation, induction of ER resident chaperones, and degradation of misfolded proteins through the ER-associated degradation. In case of severe and/or prolonged ER stress, cellular signals leading to cell death are activated. Accumulating evidence suggests that ER stress induced by aberrant protein degradation is implicated in PD. Here the authors review the emerging role of ER stress in PD and related disorders, and highlight current knowledge in this field that may reveal novel insight into disease mechanisms and help to provide novel avenues to potential therapies.

Topics: alpha-Synuclein; Animals; Endoplasmic Reticulum; Humans; Models, Biological; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Receptors, G-Protein-Coupled; Signal Transduction; Toxins, Biological; Ubiquitin-Protein Ligases

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

Our knowledge regarding the genetics of Parkinson's disease (PD) and parkinsonism has evolved dramatically during the past decade, with the discovery of numerous loci and genes. The LRRK2 gene has emerged as the most commonly involved in both familial and sporadic PD. Several variants in LRRK2 and SNCA have been associated with an increased risk of sporadic PD. PRKN, PINK1 and DJ1 mutations cause early-onset recessively inherited PD. Autosomal dominant dementia and parkinsonism is caused by mutations in the MAPT gene, and in the most recently discovered PGRN gene.

Topics: alpha-Synuclein; Genetic Predisposition to Disease; Humans; Intercellular Signaling Peptides and Proteins; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Oncogene Proteins; Parkinson Disease; Parkinsonian Disorders; Progranulins; Protein Deglycase DJ-1; Protein Serine-Threonine Kinases; tau Proteins; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is characterized by a unique clinical constellation that includes: slowness, rigidity, gait difficulty, and tremor at rest. Pathological studies have linked this presentation to the loss of midbrain dopamine neurons (Gelb et al. 1999) although other neuronal populations are also targeted in PD. Epidemiological data implicate both genetic and environmental factors in the etiology of the disease. The identification of a series of genes that underlie relatively rare, familial forms of Parkinsonism (a clinical term that encompasses 'sporadic' PD, familial Parkinson's-like forms, as well as other related syndromes) has brought excitement to the field. Three of the mutated familial Parkinsonism (FP) genes: Parkin, DJ-1, and PINK1, typically present with apparent autosomal recessive inheritance and are implicated in mitochondria and oxidative stress-related survival pathways. Two other FP genes: alpha-Synuclein (alphaSyn) and LRRK2, present in an autosomal dominant pattern and are associated with prominent intracellular protein inclusions. A series of recent publications suggest novel pathways that may link the FP genes.

Topics: alpha-Synuclein; Animals; Genetic Predisposition to Disease; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Oncogene Proteins; Oxidative Stress; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Signal Transduction; Ubiquitin-Protein Ligases

Prior to the discovery of genes associated with familial forms of Parkinson's disease, animal models of Parkinson's disease mainly consisted of toxin models based exclusively on the degeneration of nigrostriatal dopamine neurons. These traditional models have provided valuable insight into symptomatic treatments for Parkinson's disease; however, they lack the broad extra-nigral pathology and the progression that is observed in the disease. The novel genetic mouse models recently generated are advantageous because they have mutations that are known to cause familial Parkinson's disease and thus they have good construct validity. To maximize the utility of these models, a thoughtful phenotypical characterization is important. Our laboratory has assembled a battery of behavioral tests to assess sensorimotor function in genetic mouse models of Parkinsonism. This review discusses the sensitivity of these tests in different genetic mice in addition to their behavioral response to dopamine agonists.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Corpus Striatum; Dopamine; Drug Evaluation, Preclinical; Mice; Mice, Knockout; Models, Genetic; Motor Activity; Motor Skills; Neuroprotective Agents; Oncogene Proteins; Parkinsonian Disorders; Peroxiredoxins; Phenotype; Protein Deglycase DJ-1; Research Design; Substantia Nigra; Ubiquitin-Protein Ligases

Until 10 years ago, conventional wisdom held that Parkinson's disease was not a genetic disorder. Since that time, there have been a plethora of genetic findings, culminating in the cloning of several genes that derive from the loci given the nomenclature PARK1-PARK12 (OMIM 168600). Recently, these research findings have begun to impact clinical practice, and this impact is likely to increase. The primary purpose of this article is to outline these genetic advances, discuss their importance for current practice in clinical and related settings, and outline briefly how they are influencing research into the causes of and possible future treatments for this prevalent disorder.

Topics: Aged; alpha-Synuclein; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Oncogene Proteins; Parkinson Disease; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Risk; Ubiquitin-Protein Ligases

Parkinson's disease (PD), one of the most common neurodegenerative diseases, is a multifactorial disease caused by both genetic and environmental factors. Although most patients suffering from PD have a sporadic disease, several genetic causes have been identified in recent years, including alpha-synuclein, parkin, PINK1, dardarin (LRRK2), and DJ-1. DJ-1 deletions and point mutations have been found worldwide, and loss of functional protein was shown to cause autosomal recessive PD. Moreover, DJ-1 immunoreactive inclusions are found in other alpha-synucleopathies and tauopathies, indicating that different neurodegenerative diseases might share a common mechanism in which DJ-1 might play a key role. The function of DJ-1 is still unknown; however, it is associated with various cellular processes, including response to oxidative stress, cellular transformation, RNAbinding, androgen-receptor signaling, spermatogenesis, and fertilization. This article reviews the current knowledge on DJ-1, focusing on its importance in the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Cell Transformation, Viral; Dopamine; Drosophila melanogaster; Drosophila Proteins; Genes, Recessive; Humans; Intracellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Oncogene Proteins; Oxidative Stress; Parkinsonian Disorders; Peroxiredoxins; Protein Deglycase DJ-1; Tauopathies; 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 (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

Recent molecular biology research on neurodegenerative diseases, including parkinsonisms, has identified mutations in the genes that code for the proteins alpha-synuclein and tau, which have been used to classify them into synucleinopathies and tauopathies. The synucleinopathies include, besides the most common and well studied Parkinson's disease (PD), dementia with Lewy bodies, which accounts for approximately 20% of all cases of dementia in the elderly, and multiple system atrophy, whereas the tauopathies include rare and rapidly progressive syndromes, such as progressive supranuclear palsy and corticobasal degeneration. Data we collected at our center in over 2900 parkinsonian patients show that PD accounts for no more than 70% of parkinsonisms. The various syndromes have many features in common that make the differential diagnosis difficult in the early stages of disease. Our data are consistent with the findings reported in the international literature and provide additional information useful for differential diagnosis.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Female; Humans; Hypokinesia; Lewy Bodies; Male; Middle Aged; Muscle Rigidity; Nerve Tissue Proteins; Neurons; Pain; Parkinsonian Disorders; Point Mutation; Postural Balance; Substantia Nigra; Synucleins; tau Proteins; Tremor

Filamentous alpha-synuclein deposition is the defining hallmark of neurodegenerative synucleinopathies. The onset and progression of these diseases are thought to be related the formation of the alpha-synuclein filaments. We have analyzed posttranslational modifications of the filamentous alpha-synuclein in synucleinopathy brains by biochemical and protein chemical techniques. Mass spectrometric analysis revealed that deposited alpha-synuclein is highly phosphorylated at Ser129. We also found that alpha-synuclein is ubiquitinated in several synucleinopathy brains. The ubiquitination sites of soluble and filamentous alpha-synuclein were determined. These data have important implications for understanding the formation of alpha-synuclein filaments in synucleinopathy brains.

Topics: alpha-Synuclein; Brain Chemistry; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Parkinsonian Disorders; Phosphorylation; Synucleins

The understanding of the molecular mechanisms underlying Parkinson's disease, progressive supranuclear palsy, and multiple system atrophy has made significant progress in the recent years. Lewy body appears to be principally made of alpha-synuclein, a presynaptic protein. It also contains ubiquitin and some components of the proteasome: this suggests that alteration of protein catabolism may be involved in its formation. In favor of this hypothesis, it should be noted that Parkin, a protein that is mutated in autosomal recessive Parkinson disease, is a ubiquitin ligase. Immunohistochemistry has shown that alpha-synuclein accumulates not only in the cell body of the neurones (Lewy body) but also in their processes (Lewy neurites); it has emphasized the severity of the pathology in the nucleus basalis of Meynert, amygdala, CA2-3 sector of the hippocampus and cerebral cortex. Cortical Lewy bodies are not considered any more the marker of dementia with Lewy bodies: they are, indeed, found in true Parkinson disease cases. In progressive supranuclear palsy, 4 repeats tau accumulates in the cytoplasm of neurones and glia. At electron microscopy, the accumulation is made of straight filaments. It involves not only the neurones (where it is the main constituent of the neurofibrillary tangles) but also the glia. Astrocytic tuft is to day considered the morphological marker of progressive supranuclear palsy. Tau protein accumulates in the cell body of the oligodendrocyte as a "coiled body"; the protein is also integrated in the myelin sheath, when the cytoplasm of the oligodendrocyte wraps around the axon. This explains the numerous "threads" that are visible in cases of progressive supranuclear palsy. Striato-nigral degeneration, sporadic olivo-ponto-cerebellar atrophy and primitive orthostatic hypotension are various clinico-pathologic aspects of the same disorder: multiple system atrophy. It is also characterized by a morphological marker: the accumulation of alpha-synuclein in the cytoplasm of glial cells, particularly oligodendrocytes. The term synucleinopathy has been proposed to describe both idiopathic Parkinson disease and multiple system atrophy. The reason explaining the cellular topography of alpha-synuclein accumulation, neuronal in Parkinson disease, glial in multiple system atrophy is still unknown.

Topics: alpha-Synuclein; Amygdala; Axons; Cerebral Cortex; Corpus Striatum; Cysteine Endopeptidases; Hippocampus; Humans; Hypotension, Orthostatic; Immunohistochemistry; Lewy Bodies; Ligases; Multienzyme Complexes; Multiple System Atrophy; Myelin Sheath; Nerve Tissue Proteins; Neuroglia; Oligodendroglia; Olivopontocerebellar Atrophies; Parkinsonian Disorders; Presynaptic Terminals; Proteasome Endopeptidase Complex; Supranuclear Palsy, Progressive; Synucleins; tau Proteins; Ubiquitin; Ubiquitin-Protein Ligases

A paradigm shift in understanding Parkinson's disease (PD) and related disorders is emerging from studies showing that alpha-synuclein (AS) gene mutations cause familial PD; AS is abnormally nitrated, phosphorylated, and ubiquitinated; AS forms neuronal and glial inclusions; AS fibrillizes in vitro; and AS transgenic animals develop neurodegeneration with AS amyloid inclusions. Thus, PD and related synucleinopathies are brain amyloidoses that may share similar mechanisms and targets for drug discovery.

Topics: alpha-Synuclein; Amyloidosis; Animals; Brain; Humans; Inclusion Bodies; Nerve Tissue Proteins; Parkinsonian Disorders; Synucleins

In the majority of patients with Parkinson's disease (PD), it is now clear that genetic factors contribute to the pathogenesis of PD, although the contribution of genetic and environmental factors remains to be elucidated. The contribution of genetic factors to the pathogenesis of PD is supported by the demonstration of the high concordance in twins, increased risk among relatives of PD patients in case control and family studies, and the existence of familial PD based on single gene defects. Recently, several genes have been mapped and identified in patients with familial PD (FPD). alpha-Synuclein is involved in a rare dominant form of familial PD with dopa responsive parkinsonian features and Lewy body positive pathology. In contrast, parkin is responsible for autosomal recessive form of earlyonset PD with Lewy body-negative pathology. This form is identified with world-wide distribution among patients with young-onset PD. Furthermore, ubiquitin carboxy terminal hydrolase L1 (UCHL1) gene is responsible for an autosomal dominant form of typical PD, although only a single family has so far been identified with a mutation of this gene. In addition, DJ-1 has been identified as a causative gene for PARK7, a recessive form of familial PD. Now, a total of five causative genes including NR4A2 have been identified, and others such as PARK3, -4, -6, -8, -9, -10 have been mapped as hereditary forms of familial PD. The presence of different loci or different causative genes indicates that PD is not a single entity but a highly heterogeneous disorder. However, the functions of causative genes may share a common pathway such as an ubiquitin-proteasome pathway. Thus, identification and elucidation of the causative genes should enhance our understanding of the pathogenesis of not only familial PD, but also sporadic PD.

Topics: alpha-Synuclein; Humans; Intracellular Signaling Peptides and Proteins; Middle Aged; Mutation; Nerve Tissue Proteins; Oncogene Proteins; Parkinsonian Disorders; Protein Deglycase DJ-1; Substantia Nigra; Synucleins; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is a complex disorder with many different causes, yet they may intersect in common pathways, raising the possibility that neuroprotective agents may have broad applicability in the treatment of PD. Current evidence suggests that mitochondrial complex I inhibition may be the central cause of sporadic PD and that derangements in complex I cause alpha-synuclein aggregation, which contributes to the demise of dopamine neurons. Accumulation and aggregation of alpha-synuclein may further contribute to the death of dopamine neurons through impairments in protein handling and detoxification. Dysfunction of parkin (a ubiquitin E3 ligase) and DJ-1 could contribute to these deficits. Strategies aimed at restoring complex I activity, reducing oxidative stress and alpha-synuclein aggregation, and enhancing protein degradation may hold particular promise as powerful neuroprotective agents in the treatment of PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Cysteine Endopeptidases; Dopamine; Electron Transport Complex I; Humans; Mitochondria; Multienzyme Complexes; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Neurons; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Synucleins; Ubiquitin; Ubiquitin-Protein Ligases

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Brain; Humans; Lewy Bodies; Lewy Body Disease; Molecular Sequence Data; Mutation, Missense; Nerve Tissue Proteins; Parkinsonian Disorders; Phosphorylation; Protein Processing, Post-Translational; Synucleins

Parkinson's disease (PD) was noted to have a familial component as early as 1880 (Leroux, 1880). More recently, the discovery of several genetic factors influencing parkinsonism has emphasized the importance of heredity in PD. The clinical spectrum of familial parkinsonism is wide; it includes not only PD, but also dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), essential tremor, and other disorders. In the general population, it is likely that PD results from combined genetic and environmental factors, most of which are not yet known. The discovery of causal mutations in the gene for alpha-synuclein, parkin, and of genetic linkages to chromosomes 2p4, 4p5, and three loci on 1q6-8 have revolutionized PD research. This review focuses on recent progress in the Mendelian genetics of PD and those diseases in which parkinsonism is a prominent feature, and considers how these discoveries modify our beliefs regarding the etiology and pathogenesis of these disorders.

Topics: alpha-Synuclein; Chromosome Mapping; Essential Tremor; Humans; Lewy Body Disease; Ligases; Nerve Tissue Proteins; Parkinson Disease; Parkinsonian Disorders; Supranuclear Palsy, Progressive; Synucleins; Ubiquitin-Protein Ligases

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

We have reviewed recent progress in establishing the function of alpha-synuclein and parkin in relation to nigral degeneration in autosomal dominant and autosomal recessive PD. Mutations of alpha-synuclein (Ala53Thr and Ala30Pro) cause a form of autosomal dominant PD with early onset. Parkin is a novel protein expressed in the cytoplasm, including the terminal regions and Golgi apparatus. Mutations of parkin cause a form of autosomal recessive young-onset PD (ARJP). Both proteins appear to be associated with fast axonal transport. In addition, in sporadic PD, normal alpha-synuclein shows an increased tendency to self-aggregate. Thus, altered axonal transport of presynaptic proteins appears to play a crucial role in neurodegeneration in PD.

Topics: alpha-Synuclein; Humans; Ligases; Nerve Degeneration; Nerve Tissue Proteins; Parkinsonian Disorders; Synucleins; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is a neurodegenerative disease with clinical features resulting from deficiency of dopamine in the nigrostriatal system. Most PD cases are sporadic and the primary cause of the disease is still unknown. Recently, familial PD and parkinsonism have received much attention because these forms of the disease might provide clues to the genetic risk factors involved in the pathogenesis of idiopathic PD. To date, two causative genes, alpha-synuclein and the parkin gene, have been identified. alpha-Synuclein is involved in the pathogenesis of an autosomal dominant form of PD and constitutes a major component of the Lewy body, which is a pathological hallmark of idiopathic PD. In addition, mutations in the parkin gene have been identified as the cause of autosomal recessive juvenile parkinsonism (AR-JP). AR-JP manifests itself as a highly selective degeneration of the substantia nigra and the locus coeruleus, but without Lewy body formation. In addition to these two genes, four chromosomal loci have been linked to other forms of familial PD. Furthermore, there are a number of other pedigrees of familial PD in which linkage to known genetic loci has been excluded. Molecular cloning of these disease genes and elucidation of the function of their gene products will greatly contribute to our understanding of the pathogenesis of idiopathic PD.

Topics: alpha-Synuclein; Amino Acid Sequence; Brain; Humans; Lewy Bodies; Ligases; Molecular Sequence Data; Mutation; Nerve Tissue Proteins; Parkinson Disease; Parkinsonian Disorders; Proteins; Sequence Deletion; Synucleins; Ubiquitin-Protein Ligases

We review here familial Parkinson's disease (PD) from clinical as well as molecular genetic aspects. The contribution of genetic factors to the pathogenesis of PD is supported by the demonstration of the high concordance in twins, increased risk among relatives of PD patients in case control and family studies, and the existence of familial PD and parkinsonism based on single gene defects. Recently, several genes have been mapped and/or identified in patients with familial PD. Alpha-synuclein is involved in a rare dominant form of familial PD with dopa responsive parkinsonian features and Lewy body positive pathology. In contrast, parkin is responsible for autosomal recessive form of early-onset PD with Lewy body-negative pathology. This form is identified world-wide among patients with young-onset PD. Furthermore, ubiquitin carboxy terminal hydrolase L1 gene is responsible for an autosomal dominant form of typical PD, although only a single family has so far been identified with a mutation of this gene, and tau has been identified as a causative gene for frontotemporal dementia and parkinsonism. In addition, five other chromosome loci have been identified to be linked to familial PD or dystonia-parkinsonism. The presence of different loci or different causative genes indicates that PD is not a single entity but a highly heterogeneous. Identification and elucidation of the causative genes should enhance our understanding of the pathogenesis of sporadic PD.

Topics: alpha-Synuclein; Animals; DNA Mutational Analysis; Humans; Lewy Bodies; Ligases; Molecular Sequence Data; Mutation; Nerve Tissue Proteins; Parkinson Disease; Parkinsonian Disorders; Proteins; Sequence Homology, Amino Acid; Substantia Nigra; Synucleins; Thiolester Hydrolases; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases

The contribution of genetic factors in the pathogenesis of PD is supported by the demonstration of the high concordance in twins studies using PET, the increased risk among relatives of PD patients in case control and family studies, and the existence of familial PD and parkinsonism by single gene defect. Recently, two genes such as alpha-synuclein and parkin have been identified. alpha-Synuclein is involved in a rare dominant form of familial PD with dopa responsive parkinsonian features and Lewy body positive pathology. In contrast, parkin is responsible for autosomal recessive form (AR-JP) of early onset PD with Lewy body-negative pathology. To date, variable mutations such as deletions or point mutations have been reported in AR-JP patients from world wide. In addition, the localization of parkin indicates parkin may are involved in the axonal transport system. More recently, we have found that parkin interacts with ubiquitin-conjugating enzyme, UbcH 7, and is functionally linked to the ubiquitin-proteasome pathway as a ubiquitin ligase. These findings fit the characteristics of lack of Lewy bodies which are cytoplasmic inclusions considered a pathological hallmark. Our findings should enhance the exploration of the mechanisms of neuronal death in PD as well as other neurodegenerative disorders of which variable inclusion bodies are observed.

Topics: alpha-Synuclein; Cysteine Endopeptidases; Genes, Recessive; Humans; Lewy Bodies; Ligases; Multienzyme Complexes; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Synucleins; Ubiquitin-Conjugating Enzymes; Ubiquitin-Protein Ligases; Ubiquitins

Despite being considered the archetypal non-genetic neurological disorder, genetic analysis of Parkinson's disease has shown that there are at least three genetic loci. Furthermore, these analyses have suggested that the phenotype of the pathogenic loci is wider than simple Parkinson's disease and may include Lewy body dementia and some forms of essential tremor. Identification of alpha-synuclein as the first of the loci involved in Parkinson's disease and the identification of this protein in pathological deposits in other disorders has led to the suggestion that it may share pathogenic mechanisms with multiple system atrophy, Alzheimer's disease and prion disease and that these mechanisms are related to a synuclein pathway to cell death. Finally, genetic analysis of the synuclein diseases and the tau diseases may indicate that this synuclein pathway is an alternative to the tau pathway to cell death.

Topics: alpha-Synuclein; Alzheimer Disease; Humans; Multiple System Atrophy; Nerve Tissue Proteins; Parkinsonian Disorders; Supranuclear Palsy, Progressive; Synucleins; tau Proteins

The early differential diagnosis of Parkinson's disease (PD) and atypical Parkinsonian syndromes (APS), including corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), is challenging because of an overlap of clinical features and the lack of reliable biomarkers. Neural-derived extracellular vesicles (NDEVs) isolated from blood provide a window into the brain's biochemistry and may assist in distinguishing between PD and APS. We verified in a case-control study whether oligomeric α-Synuclein and Tau aggregates isolated from NDEVs could allow the differential diagnosis of these conditions. Blood sampling and clinical data, including disease duration, motor severity, global cognition, and levodopa equivalent daily dose (LEDD), were collected from patients with a diagnosis of either PD (n = 70), PSP (n = 21), or CBD (n = 19). NDEVs were isolated from serum by immunocapture using an antibody against the neuronal surface marker L1CAM; oligomeric α-Synuclein and aggregated Tau were measured by ELISA. NDEVs analyses showed that oligomeric α-Synuclein is significantly augmented in PD compared to APS, whereas Tau aggregates are significantly increased in APS compared to PD (p < 0.0001). ROC analyses showed that these two biomarkers have a "good" power of classification (p < 0.0001 for both proteins), with high sensitivity and specificity, with NDEVs concentration of Tau aggregates and oligomeric α-Synuclein being respectively the best biomarker for PD/PSP and PD/CBD diagnostic differentiation. Logistic and multiple regression analysis confirmed that NDEVs-derived oligomeric α-Synuclein and Tau aggregates differentiate PD from CBD and PSP (p < 0.001). Notably, a positive correlation between NDEVs oligomeric α-Synuclein and disease severity (disease duration, p = 0.023; Modified H&Y, p = 0.015; UPDRS motor scores, p = 0.004) was found in PD patients and, in these same patients, NDEVs Tau aggregates concentration inversely correlated with global cognitive scores (p = 0.043). A minimally invasive blood test measuring the concentration of α-synuclein and Tau aggregates in NDEVs can represent a promising tool to distinguish with high sensitivity and specificity PD from CBD or PSP patients. Optimization and validation of these data will be needed to confirm the diagnostic value of these biomarkers in distinguishing synucleinopathies from taupathies.

Topics: alpha-Synuclein; Biomarkers; Case-Control Studies; Extracellular Vesicles; Humans; Parkinson Disease; Parkinsonian Disorders; Supranuclear Palsy, Progressive; tau Proteins

The amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC) of Guam is an endemic neurodegenerative disease that features widespread tau tangles, occasional α-synuclein Lewy bodies, and sparse β-amyloid (Aβ) plaques distributed in the central nervous system. Extensive studies of genetic or environmental factors have failed to identify a cause of ALS-PDC. Building on prior work describing the detection of tau and Aβ prions in Alzheimer's disease (AD) and Down syndrome brains, we investigated ALS-PDC brain samples for the presence of prions. We obtained postmortem frozen brain tissue from 26 donors from Guam with ALS-PDC or no neurological impairment and 71 non-Guamanian donors with AD or no neurological impairment. We employed cellular bioassays to detect the prion conformers of tau, α-synuclein, and Aβ proteins in brain extracts. In ALS-PDC brain samples, we detected high titers of tau and Aβ prions, but we did not detect α-synuclein prions in either cohort. The specific activity of tau and Aβ prions was increased in Guam ALS-PDC compared with sporadic AD. Applying partial least squares regression to all biochemical and prion infectivity measurements, we demonstrated that the ALS-PDC cohort has a unique molecular signature distinguishable from AD. Our findings argue that Guam ALS-PDC is a distinct double-prion disorder featuring both tau and Aβ prions.

Topics: alpha-Synuclein; Alzheimer Disease; Amyotrophic Lateral Sclerosis; Dementia; Humans; Neurodegenerative Diseases; Parkinsonian Disorders; Prion Diseases; Prions; tau Proteins

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

Learning and memory mainly rely on correct synaptic function in the hippocampus and other brain regions. In Parkinson's disease, subtle cognitive deficits may even precede motor signs early in the disease. Hence, we set out to unravel the earliest hippocampal synaptic alterations associated with human α-synuclein overexpression prior to and soon after the appearance of cognitive deficits in a parkinsonism model. We bilaterally injected adeno-associated viral vectors encoding A53T-mutated human α-synuclein into the substantia nigra of rats, and evaluated them 1, 2, 4 and 16 weeks post-inoculation by immunohistochemistry and immunofluorescence to study degeneration and distribution of α-synuclein in the midbrain and hippocampus. The object location test was used to evaluate hippocampal-dependent memory. Sequential window acquisition of all theoretical mass spectrometry-based proteomics and fluorescence analysis of single-synapse long-term potentiation were used to study alterations to protein composition and plasticity in isolated hippocampal synapses. The effect of L-DOPA and pramipexole on long-term potentiation was also tested. Human α-synuclein was found within dopaminergic and glutamatergic neurons of the ventral tegmental area, and in dopaminergic, glutamatergic and GABAergic axon terminals in the hippocampus from 1 week post-inoculation, concomitant with mild dopaminergic degeneration in the ventral tegmental area. In the hippocampus, differential expression of proteins involved in synaptic vesicle cycling, neurotransmitter release and receptor trafficking, together with impaired long-term potentiation were the first events observed (1 week post-inoculation), preceding cognitive deficits (4 weeks post-inoculation). Later on, at 16 weeks post-inoculation, there was a deregulation of proteins involved in synaptic function, particularly those involved in the regulation of membrane potential, ion balance and receptor signalling. Hippocampal long-term potentiation was impaired before and soon after the onset of cognitive deficits, at 1 and 4 weeks post-inoculation, respectively. L-DOPA recovered hippocampal long-term potentiation more efficiently at 4 weeks post-inoculation than pramipexole, which partially rescued it at both time points. Overall, we found impaired synaptic plasticity and proteome dysregulation at hippocampal terminals to be the first events that contribute to the development of cognitive deficits in experimental parkinsonism. Our results

Topics: alpha-Synuclein; Animals; Cognition; Dopamine; Dopaminergic Neurons; Hippocampus; Humans; Levodopa; Neurotransmitter Agents; Parkinson Disease; Parkinsonian Disorders; Pramipexole; Rats

Topics: alpha-Synuclein; Autoantibodies; Glucosylceramidase; Humans; Mutation; Parkinsonian Disorders

The discovery of biogenic aldehydes in the postmortem parkinsonian brain and the ability of these aldehydes to modify and cross-link proteins has called attention to their possible role in Parkinson's disease. For example, many in vitro studies have found that the aldehyde metabolite of dopamine, 3,4-dihydroxyphenylacetaldehyde (DOPAL), induces the formation of stable, neurotoxic alpha-synuclein oligomers.. To study this in vivo, mice deficient in the two aldehyde dehydrogenase enzymes (Aldh1a1 and Aldh2, DKO) primarily responsible for detoxification of DOPAL in the nigrostriatal pathway were crossed with mice that overexpress human wild-type alpha-synuclein. DKO overexpressing human wild-type alpha-synuclein (DKO/ASO) offspring were evaluated for impairment on motor tasks associated with Parkinsonism.. DKO/ASO mice developed severe motor deficits greater than that of mice overexpressing human wild-type alpha-synuclein alone.. These results provide evidence to support the idea that biogenic aldehydes such as DOPAL interact with human wild-type alpha-synuclein, directly or indirectly, in vivo to exacerbate locomotor deficits in Parkinson's disease.

Topics: Aldehydes; alpha-Synuclein; Animals; Dopamine; Humans; Mice; Parkinson Disease; Parkinsonian Disorders

Topics: alpha-Synuclein; Humans; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders

Parkinson's disease (PD) may be misdiagnosed due to the clinical overlap between PD and atypical parkinsonism. The utility of α-Synuclein (αSyn) Seed Amplification Assay (SAA) as a diagnostic indicator for PD has been reported in numerous studies, but never when administered as a validated clinical laboratory test. This study compares results from αSyn-SAA validation testing performed using well-characterized cohorts from two biorepositories to better understand the accuracy of PD clinical diagnosis. Blinded cerebrospinal fluid (CSF) specimens from a repository that included cohorts of subjects clinically diagnosed as PD or healthy controls, both with confirmatory dopamine transporter single-photon emission computed tomography (DAT SPECT) imaging, and blinded CSF specimens from a repository that included cohorts of subjects clinically diagnosed as PD or healthy controls based on clinical diagnosis alone, were tested as part of the validation studies for the diagnostic αSyn-SAA test (SYNTap® Biomarker Test). Measured αSyn-SAA test accuracy was 83.9% using clinical diagnosis as comparator, and 93.6% using clinical diagnosis with confirmatory DAT- SPECT imaging as comparator. The statistically significant discordance between accuracy determinations using specimens classified using different diagnostic inclusion criteria indicates that there is some symbiosis between dopamine-weighted imaging and αSyn-SAA results, both of which are associated with higher accuracy compared with the clinical diagnosis alone.

Topics: alpha-Synuclein; Dopamine; Humans; Parkinson Disease; Parkinsonian Disorders

Effects of the endogenous neuroprotector isatin and the pharmacological drug afobazole (exhibiting neuroprotective properties) on behavioral reactions and quantitative changes in the brain proteomic profile have been investigated in rats with experimental rotenone Parkinsonism. A single dose of isatin (100 mg/kg subcutaneously on the last day of a 7-day course of rotenone administration) improved the motor activity of rats with rotenone-induced Parkinsonism in the open field test (horizontal movements) and the rotating rod test. Afobazole (10 mg/kg intraperitoneally, daily during the 7-day course of rotenone administration) reduced the manifestations of rigidity and postural instability. Proteomic analysis, performed using brain samples obtained the day after the last administration of rotenone and neuroprotectors, revealed similar quantitative changes in the brain of rats with rotenone Parkinsonism. An increase in the relative content of 65 proteins and a decrease in the relative content of 21 proteins were detected. The most pronounced changes - an almost ninety-fold increase in the alpha-synuclein content - were found in the brains of rats treated with isatin. In animals of the experimental groups treated with "Rotenone + Isatin", as well as "Rotenone + Afobazole", the increase in the relative content of this protein in the brain was almost 60 and 50 times higher than the control values. Taking into consideration the known data on the physiological role of alpha-synuclein, an increase in the content of this protein in the brain upon administration of neuroprotectors to animals with rotenone Parkinsonism may represent a compensatory reaction, at least in the early stages of this disease and the beginning of its treatment.

Topics: alpha-Synuclein; Animals; Brain; Isatin; Neuroprotective Agents; Octoxynol; Parkinsonian Disorders; Proteomics; Rats; Rotenone

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

Topics: alpha-Synuclein; Frontotemporal Lobar Degeneration; Humans; Multiple System Atrophy; Parkinsonian Disorders; Synucleinopathies

Previous studies reported skin phosphorylated α-synuclein (p-syn) deposits in Parkinson's disease (PD) patients but not in patients with parkinsonism due to tauopathies, although data on the latter are limited.. We aimed to assess the presence of skin p-syn deposits in patients with clinical diagnosis of parkinsonism usually due to tauopathy and PD.. We consecutively recruited 26 patients, 18 fulfilling clinical diagnostic criteria of progressive supranuclear palsy (PSP) and 8 of corticobasal syndrome (CBS), 26 patients with PD, and 26 healthy controls (HC). All subjects underwent skin biopsy to study p-syn deposits in skin nerves by immunofluorescence.. Skin p-syn deposits were present in only two of the PSP/CBS patients and none of the HC. Conversely, all PD patients showed p-syn deposition (p < 0.001, Chi-square). The two p-syn positive patients were diagnosed with PSP and CBS, respectively. Although clinical and MRI findings supported these diagnoses, both patients had some atypical features more typical of synucleinopathies.. The detection of skin p-syn deposits may help in the differential diagnosis of parkinsonism. Indeed, in this study, all PD patients and only two out of 26 with a clinical diagnosis of PSP/CBS had skin p-syn deposits. Furthermore, these two patients showed clinical features that could suggest an atypical synucleinopathy presentation or a mixed pathology.

Topics: alpha-Synuclein; Corticobasal Degeneration; Humans; Parkinson Disease; Parkinsonian Disorders; Supranuclear Palsy, Progressive

Multiple system atrophy (MSA) is a neurodegenerative condition characterized by variable combinations of parkinsonism, autonomic failure, cerebellar ataxia and pyramidal features. Although the distribution of synucleinopathy correlates with the predominant clinical features, the burden of pathology does not fully explain observed differences in clinical presentation and rate of disease progression. We hypothesized that the clinical heterogeneity in MSA is a consequence of variability in the seeding activity of α-synuclein both between different patients and between different brain regions.. The reliable detection of α-synuclein seeding activity derived from MSA using cell-free amplification assays remains challenging. Therefore, we conducted a systematic evaluation of 168 different reaction buffers, using an array of pH and salts, seeded with fully characterized brain homogenates from one MSA and one PD patient. We then validated the two conditions that conferred the optimal ability to discriminate between PD- and MSA-derived samples in a larger cohort of 40 neuropathologically confirmed cases, including 15 MSA. Finally, in a subset of brains, we conducted the first multi-region analysis of seeding behaviour in MSA.. Using our novel buffer conditions, we show that the physicochemical factors that govern the in vitro amplification of α-synuclein can be tailored to generate strain-specific reaction buffers that can be used to reliably study the seeding capacity from MSA-derived α-synuclein. Using this novel approach, we were able to sub-categorize the 15 MSA brains into 3 groups: high, intermediate and low seeders. To further demonstrate heterogeneity in α-synuclein seeding in MSA, we conducted a comprehensive multi-regional evaluation of α-synuclein seeding in 13 different regions from 2 high seeders, 2 intermediate seeders and 2 low seeders.. We have identified unexpected differences in seed-competent α-synuclein across a cohort of neuropathologically comparable MSA brains. Furthermore, our work has revealed a substantial heterogeneity in seeding activity, driven by the PBS-soluble α-synuclein, between different brain regions of a given individual that goes beyond immunohistochemical observations. Our observations pave the way for future subclassification of MSA, which exceeds conventional clinical and neuropathological phenotyping and considers the structural and biochemical heterogeneity of α-synuclein present. Finally, our methods provide an experimental framework for the development of vitally needed, rapid and sensitive diagnostic assays for MSA.

Topics: alpha-Synuclein; Brain; Humans; Multiple System Atrophy; Parkinsonian Disorders; Synucleinopathies

Synaptic impairment might precede neuronal degeneration in Parkinson's disease. However, the intimate mechanisms altering synaptic function by the accumulation of presynaptic α-synuclein in striatal dopaminergic terminals before dopaminergic death occurs, have not been elucidated. Our aim is to unravel the sequence of synaptic functional and structural changes preceding symptomatic dopaminergic cell death. As such, we evaluated the temporal sequence of functional and structural changes at striatal synapses before parkinsonian motor features appear in a rat model of progressive dopaminergic death induced by overexpression of the human mutated A53T α-synuclein in the substantia nigra pars compacta, a protein transported to these synapses. Sequential window acquisition of all theoretical mass spectra proteomics identified deregulated proteins involved first in energy metabolism and later, in vesicle cycling and autophagy. After protein deregulation and when α-synuclein accumulated at striatal synapses, alterations to mitochondrial bioenergetics were observed using a Seahorse XF96 analyser. Sustained dysfunctional mitochondrial bioenergetics was followed by a decrease in the number of dopaminergic terminals, morphological and ultrastructural alterations, and an abnormal accumulation of autophagic/endocytic vesicles inside the remaining dopaminergic fibres was evident by electron microscopy. The total mitochondrial population remained unchanged whereas the number of ultrastructurally damaged mitochondria increases as the pathological process evolved. We also observed ultrastructural signs of plasticity within glutamatergic synapses before the expression of motor abnormalities, such as a reduction in axospinous synapses and an increase in perforated postsynaptic densities. Overall, we found that a synaptic energetic failure and accumulation of dysfunctional organelles occur sequentially at the dopaminergic terminals as the earliest events preceding structural changes and cell death. We also identify key proteins involved in these earliest functional abnormalities that may be modulated and serve as therapeutic targets to counterbalance the degeneration of dopaminergic cells to delay or prevent the development of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Autophagy; Corpus Striatum; Dopamine; Dopaminergic Neurons; Energy Metabolism; Parkinson Disease; Parkinsonian Disorders; Rats

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

Differential diagnosis between Parkinson's disease (PD) and atypical parkinsonisms (APs: multiple system atrophy[MSA], progressive supranuclear palsy[PSP], corticobasal degeneration[CBD]) remains challenging. Lately, cerebrospinal fluid (CSF) studies of neurofilament light-chain (NFL) and RT-QuIC of alpha-synuclein (α-SYN) have shown promise, but data on their combination with MRI measures is lacking.. (1) to assess the combined diagnostic ability of CSF RT-QuIC α-SYN, CSF NFL and midbrain/pons MRI planimetry in degenerative parkinsonisms; (2) to evaluate if biomarker-signatures relate to clinical diagnoses and whether or not unexpected findings can guide diagnostic revision.. We collected demographic and clinical data and set up α-SYN RT-QuIC at our lab in a cross-sectional cohort of 112 participants: 19 control subjects (CSs), 20PD, 37MSA, 23PSP, and 13CBD cases. We also determined CSF NFL by ELISA and, in 74 participants (10CSs, 9PD, 26MSA, 19PSP, 10CBD), automatized planimetric midbrain/pons areas from 3T-MRI.. Sensitivity of α-SYN RT-QuIC for PD was 75% increasing to 81% after revisiting clinical diagnoses with aid of biomarkers. Sensitivity for MSA was 12% but decreased to 9% with diagnostic revision. Specificities were 100% against CSs, and 89% against tauopathies raising to 91% with diagnostic revision. CSF NFL was significantly higher in APs. The combination of biomarkers yielded high diagnostic accuracy (PD vs. non-PD AUC = 0.983; MSA vs. non-MSA AUC = 0.933; tauopathies vs. non-tauopathies AUC = 0.924). Biomarkers-signatures fitted in most cases with clinical classification.. The combination of CSF NFL, CSF RT-QuIC α-SYN and midbrain/pons MRI measures showed high discriminant ability across all groups. Results opposite to expected can assist diagnostic reclassification.

Topics: alpha-Synuclein; Biomarkers; Cross-Sectional Studies; Humans; Mesencephalon; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders; Pons; Tauopathies

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

Paraquat (PQ) is the most widely used herbicide in the world and a well-known potent neurotoxin for humans. PQ exposure has been linked to increase the risk of Parkinson's disease (PD). However, the mechanism underlying its neurotoxic effects in PD pathogenesis is unclear. In our present study, C57BL/6J mice treated with PQ manifested severe motor deficits indicated by the significant reductions in suspension score, latency to fall from rotarod, and grip strength at 8 weeks after PQ exposure. Pathological hallmarks of Parkinsonism in the midbrain such as dopaminergic neuron loss, increased α-synuclein protein, and dysregulated PD-related genes were observed. Non-targeted lipidome analysis demonstrated that PQ exposure alters lipid profile and abundance, increases pro-inflammatory lipids.27 significantly altered subclasses of lipids belonged to 6 different lipid categories. Glycerophospholipids, sphingolipids, and glycerides were the most abundant lipids. Abundance of pro-inflammatory lipids such as Cer, LPC, LPS, and LPI was significantly increased in the midbrain. mRNA expressions of genes regulating ceramide biosynthesis in the midbrain were markedly up-regulated. Moreover, PQ exposure increased serum pro-inflammatory cytokines and provoked neuroinflammation in the midbrain. Pro-inflammatory lipids and cytokines in the midbrain were positively correlated with motor deficits. PQ poisoning in humans significantly also elevated serum pro-inflammatory cytokines and induced an intense systemic inflammation. In summary, we presented initial investigations of PQ induced molecular events related to the PD pathogenesis, capturing aspects of disturbed lipid metabolism, neuroinflammation, impairment of dopaminergic neurons in the midbrain, and an intense systemic inflammation. These neurotoxic effects of PQ exposure may mechanistically contribute to the pathogenesis of PQ induced Parkinsonism. Results of this study also strongly support the hypothesis that ever-increasing prevalence of Parkinson's disease is etiologically linked to the health risk of exposure to neurotoxic environmental pollutants.

Topics: alpha-Synuclein; Animals; Ceramides; Cytokines; Environmental Pollutants; Glycerides; Glycerophospholipids; Herbicides; Humans; Lipopolysaccharides; Mesencephalon; Mice; Mice, Inbred C57BL; Neuroinflammatory Diseases; Neurotoxicity Syndromes; Neurotoxins; Paraquat; Parkinson Disease; Parkinsonian Disorders; RNA, Messenger; Sphingolipids

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

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

The role of peripheral phosphorylated-α-Synuclein (p-α-syn) deposition on nerve degeneration in synucleinopathies is still unknown.. To assess the cutaneous neural distribution of p-α-Syn deposits and its correlation with clinical data and with morphology and function of cutaneous sensory and autonomic nerves in early Parkinson's disease (PD) and multiple system atrophy-parkinson type (MSA-p).. We recruited 57 PD (F/M = 21/36; age 63.5±9.4 years) and 43 MSA-p (F/M = 16/27; age 62.3±9.0 years) patients within 2 years from motor symptoms. We applied questionnaires and clinical scales, sensory thresholds, and sudomotor testing to assess severity of motor and non-motor involvement and sensory and autonomic dysfunction. We quantified, in skin biopsy from thigh, leg, and fingertip, epidermal, pilomotor, and sudomotor nerve fibers, Meissner corpuscles and intrapapillary myelinated endings and the neural distribution of p-α-syn deposits.. Compared to controls, we found a cutaneous denervation paralleling functional and clinical impairment. Sensory and autonomic denervation was more severe in MSA-p than in PD. Deposits of p-α-syn were found in the majority of patients, with no significant differences among sites in both groups. Higher occurrence of p-α-syn deposits in autonomic nerves differentiated (p < 0.01) PD from MSA-p. p-α-syn deposits correlated positively with sudomotor function, epidermal, pilomotor and sudomotor nerve densities, and inversely with non-motor symptoms and disease progression.. Our work demonstrated an early peripheral sensory and autonomic involvement in synucleinopathies, more severe in MSA-p than in PD. Higher p-α-syn deposits in autonomic nerves differentiated PD from MSA-p. p-α-syn deposits were associated with preserved innervation and slower disease progression.

Topics: Aged; alpha-Synuclein; Female; Humans; Male; Middle Aged; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders; Skin; Synucleinopathies

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

Mutations in glucocerebrosidase (GBA) are the most prevalent genetic risk factor for Lewy body disorders (LBD)-collectively Parkinson's disease, Parkinson's disease dementia and dementia with Lewy bodies. Despite this genetic association, it remains unclear how GBA mutations increase susceptibility to develop LBD. We investigated relationships between LBD-specific glucocerebrosidase deficits, GBA-related pathways, and α-synuclein levels in brain tissue from LBD and controls, with and without GBA mutations. We show that LBD is characterised by altered sphingolipid metabolism with prominent elevation of ceramide species, regardless of GBA mutations. Since extracellular vesicles (EV) could be involved in LBD pathogenesis by spreading disease-linked lipids and proteins, we investigated EV derived from post-mortem cerebrospinal fluid (CSF) and brain tissue from GBA mutation carriers and non-carriers. EV purified from LBD CSF and frontal cortex were heavily loaded with ceramides and neurodegeneration-linked proteins including alpha-synuclein and tau. Our in vitro studies demonstrate that LBD EV constitute a "pathological package" capable of inducing aggregation of wild-type alpha-synuclein, mediated through a combination of alpha-synuclein-ceramide interaction and the presence of pathological forms of alpha-synuclein. Together, our findings indicate that abnormalities in ceramide metabolism are a feature of LBD, constituting a promising source of biomarkers, and that GBA mutations likely accelerate the pathological process occurring in sporadic LBD through endolysosomal deficiency.

Topics: alpha-Synuclein; Ceramides; Extracellular Vesicles; Glucosylceramidase; Humans; Mutation; Parkinsonian Disorders; Protein Aggregation, Pathological

Autophagic dysregulation and lysosomal impairment have been implicated in the pathogenesis of Parkinson's disease, partly due to the identification of mutations in multiple genes involved in these pathways such as GBA, SNCA, ATP13a2 (also known as PARK9), TMEM175 and LRRK2. Mutations resulting in lysosomal dysfunction are proposed to contribute to Parkinson's disease by increasing α-synuclein levels, that in turn may promote aggregation of this protein. Here, we used two different genetic models-one heterozygous for a mutated form of the GBA protein (D409V), and the other heterozygous for an ATP13a2 loss-of-function mutation, to test whether these mutations exacerbate the spread of α-synuclein pathology following injection of α-synuclein preformed fibrils in the olfactory bulb of 12-week-old mice. Contrary to our hypothesis, we found that mice harboring GBA D409V

Topics: alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Glucosylceramidase; Heterozygote; Locomotion; Loss of Function Mutation; Mice; Mutation; Olfactory Bulb; Olfactory Cortex; Parkinson Disease; Parkinsonian Disorders; Perirhinal Cortex; Prodromal Symptoms; Protein Aggregates; Proton-Translocating ATPases; Smell

Topics: alpha-Synuclein; Humans; Mutation; Parkinsonian Disorders; Phenotype

Topics: alpha-Synuclein; Humans; Mutation; Parkinsonian Disorders; Phenotype

Current treatments for Parkinson's disease (PD) provide only symptomatic relief, with no disease-modifying therapies identified to date. Repurposing FDA-approved drugs to treat PD could significantly shorten the time needed for and reduce the costs of drug development compared with conventional approaches. We developed an efficient strategy to screen for modulators of β-glucocerebrosidase (GCase), a lysosomal enzyme that exhibits decreased activity in patients with PD, leading to accumulation of the substrate glucosylceramide and oxidized dopamine and α-synuclein, which contribute to PD pathogenesis. Using a GCase fluorescent probe and affinity-based fluorescence polarization assay, we screened 1280 structurally diverse, bioactive, and cell-permeable FDA-approved drugs and found that the antipsychotic quetiapine bound GCase with high affinity. Moreover, quetiapine treatment of induced pluripotent stem cell-derived (iPSC-derived) dopaminergic neurons from patients carrying mutations in GBA1 or LRRK2 led to increased wild-type GCase protein levels and activity and partially lowered accumulation of oxidized dopamine, glucosylceramide, and α-synuclein. Similarly, quetiapine led to activation of wild-type GCase and reduction of α-synuclein in a GBA mutant mouse model (Gba1D409V/+ mice). Together, these results suggest that repurposing quetiapine as a modulator of GCase may be beneficial for patients with PD exhibiting decreased GCase activity.

Topics: alpha-Synuclein; Animals; Antipsychotic Agents; Dopaminergic Neurons; Drug Evaluation, Preclinical; Drug Repositioning; Glucosylceramidase; Glucosylceramides; Humans; Induced Pluripotent Stem Cells; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Parkinson Disease; Parkinsonian Disorders; Quetiapine Fumarate

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. PD is pathologically characterized by the death of midbrain dopaminergic neurons and the accumulation of intracellular protein inclusions called Lewy bodies or Lewy neurites. The major component of Lewy bodies is α-synuclein (α-syn). Prion-like propagation of α-syn has emerged as a novel mechanism in the progression of PD. This mechanism has been investigated to reveal factors that initiate Lewy pathology with the aim of preventing further progression of PD. Here, we demonstrate that coxsackievirus B3 (CVB3) infection can induce α-syn-associated inclusion body formation in neurons which might act as a trigger for PD. The inclusion bodies contained clustered organelles, including damaged mitochondria with α-syn fibrils. α-Syn overexpression accelerated inclusion body formation and induced more concentric inclusion bodies. In CVB3-infected mice brains, α-syn aggregates were observed in the cell body of midbrain neurons. Additionally, α-syn overexpression favored CVB3 replication and related cytotoxicity. α-Syn transgenic mice had a low survival rate, enhanced CVB3 replication, and exhibited neuronal cell death, including that of dopaminergic neurons in the substantia nigra. These results may be attributed to distinct autophagy-related pathways engaged by CVB3 and α-syn. This study elucidated the mechanism of Lewy body formation and the pathogenesis of PD associated with CVB3 infection.

Topics: alpha-Synuclein; Animals; Brain; Coxsackievirus Infections; Enterovirus B, Human; Humans; Lewy Bodies; Mice; Mice, Transgenic; Neurons; Parkinsonian Disorders

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

The SGT1 protein is highly expressed in the mammalian brain, particularly in neurons of the hippocampus and cortex, and in Purkinje cells of the cerebellum. There are literature data indicating that the protein may be involved in pathogenesis of neurodegenerative disorders such as Parkinson's disease (PD). In the present work we have found that SGT1 protected cells from the toxicity of rotenone, an agent that evokes behavioral and histopathological symptoms of PD. To gain more insight into the possible mechanism underlying the protective action of SGT1 we looked at α-synuclein subcellular distribution in HEK293 cells with an altered SGT1 level. By immunofluorescent staining we have found that in HEK293 cells overexpressing SGT1 α-synuclein was mainly localized in the cytoplasm while in control cells it was present in the nucleus. Accordingly, when SGT1 expression was silenced, α-synuclein was predominantly present in the nucleus. These results were then confirmed by subcellular fractionation and Western blot analysis. Moreover, we have found that altered level of SGT1 in HEK293 cells influenced the expression of PD related genes,

Topics: alpha-Synuclein; HEK293 Cells; Humans; Parkinson Disease; Parkinsonian Disorders

Parkinsonism is an age-associated neurodegenerative disorder characterized by aggregation of α-synuclein (α-syn) protein in the substantia nigra region, degeneration of dopaminergic neurons, and deregulated lipid metabolism. Currently, only symptomatic relief has been provided by FDA-approved therapeutic approaches for Parkinson's disease (PD). The present study aims to evaluate the potential of wedelolactone (WDL), a natural occurring coumestan found in Eclipta alba to mitigate the parkinsonism in Caenorhabditis elegans disease model. In the present studies, supplementation with 37.5 μM WDL exhibited a reduction in the level of α-syn in an age-dependent manner (22% at day 5, p < 0.05; and 16% at day 10, p < 0.001, n = 30), along with improvement in neuronal health through basal movement, and elevated the dopamine levels evident through 1-nonanol repulsion results in wild-type and diseased worms. Moreover, WDL augmented the mitochondrial health in wild-type, PD-diseased, and mev-1 mutant worms that establish the inherent activity of WDL in the alleviation of oxidative stress. Furthermore, WDL supplementation significantly decreases the neutral lipid and triglyceride level and also alleviates protein carbonyl level in PD disease condition. The overall investigation will provide a pioneer to the future insights of PD research related to plant-based drugs. qPCR studies after WDL supplementation revealed alteration of genes involved in the regulation of various stress-responsive (sod-5, gst-4, skn-1), α-syn-suppressing (lrk-1, ymel-1, lagr-1, grk-1), and mitochondrial (pink-1) genes. All together, these findings support that the WDL is a promising candidate to combat age-related multi-factorial PD pathology associated with protein misfolding and accumulation. The results provide sufficient information in the development of therapeutic medicines from natural products for improving the health.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antioxidants; Behavior, Animal; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Coumarins; DNA-Binding Proteins; Dopamine; Gene Expression Regulation; Lipids; Mitochondria; NF-E2-Related Factor 2; Oxidative Stress; Parkinsonian Disorders; Protein Aggregates; Protein Carbonylation; Reactive Oxygen Species; Stress, Physiological; Transcription Factors

Widespread accumulation of misfolded α-synuclein aggregates is a key feature of Parkinson's disease (PD). Although the pattern and extent of α-synuclein accumulation through PD brains is known, the impact of chronic dopamine-replacement therapy (the gold-standard pharmacological treatment of PD) on the fate of α-synuclein is still unknown. Here, we investigated the distribution and accumulation of α-synuclein in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) non-human primate model of PD and determined the effect of chronic L-DOPA treatment on MPTP-induced α-synuclein pathology.. We measured the density of α-synuclein and tau immuno-positive neurons in the substantia nigra, putamen, hippocampal CA1 region, temporal cortex and dentate nucleus of control, MPTP and MPTP+L-DOPA-treated monkeys. Moreover, we also extracted and quantified Triton-X (TX) soluble and insoluble α-synuclein in putamen and hippocampus samples from a separate cohort of control, MPTP and MPTP+L-DOPA-treated monkeys.. MPTP-induced α-synuclein accumulation in NHP model of PD was not limited to the substantia nigra but also occurred in the putamen, hippocampal CA1 region and temporal cortex. Tau was increased only in the temporal cortex. Moreover, increased intraneuronal TX insoluble α-synuclein was truncated, but not in the structural form of Lewy bodies. The MPTP-induced increase in α-synuclein levels was abolished in animals having received L-DOPA in all the brain regions, except in the substantia nigra.. Dopamine replacement therapy can dramatically ameliorate α-synuclein pathology in the MPTP NHP model of PD. Therefore, patient's dopaminergic medication should be systematically considered when assessing α-synuclein as a biomarker for diagnosis, monitoring disease progression and response to disease-modifying treatments.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Brain; Dopamine Agents; Female; Levodopa; Macaca mulatta; Neurons; Parkinsonian Disorders

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), the second most common progressive neurodegenerative disorder, is characterized by the abnormal accumulation of intraneuronal inclusions enriched in aggregated α-synuclein (α-syn), known as Lewy bodies (LBs) and Lewy neurites (LNs), and significant loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) of the brain. Recent evidence suggests that the intrastriatal inoculation of α-syn preformed fibrils (PFF) in mice brain triggers endogenous α-syn in interconnected brain regions. 1-methyl, 4-phenyl, 1,2,3,6 tetrahydropyridine (MPTP), a mitochondrial neurotoxin, has been used previously to generate a PD mouse model. However, the common methods of MPTP exposure do not induce LB or α-syn aggregation in mice. In the present study, we evaluated the effect of different doses of MPTP (10 mg/kg.b.wt and/or 25 mg/kg.b.wt) on the spread, accumulation, and toxicity of endogenous α-syn in mice administered an intrastriatal injection of human α-syn PFF.. We inoculated human WT α-syn PFF in mouse striatum. At 6 weeks post PFF injection, we challenged the animal with two different doses of MPTP (10 mg/kg.b.wt and 25 mg/kg.b.wt) once daily for five consecutive days. At 2 weeks from the start of the MPTP regimen, we collected the mice brain and performed immunohistochemical analysis, and Rotarod test to assess motor coordination and muscle strength before and after MPTP injection.. A single injection of human WT α-syn PFF in the mice striatum induced the propagation of α-syn, occurring as phosphorylated α-synuclein (pS129), towards the SNpc, within a very short time. Injection of a low dose of MPTP (10 mg/kg.b.wt) at 6 weeks post α-syn PFF inoculation further enhanced the spread, whereas a high dose of MPTP (25 mg/kg.b.wt.) reduced the spread. Majority of the accumulated α-syn were proteinase K resistant, as recognized using a conformation-specific α-syn antibody. Injection of α-syn PFF alone caused 12 % reduction in the number of tyrosine hydroxylase positive neurons while α-syn PFF + a low dose of MPTP caused 33 % reduction (loss), compared to the control mice injected with saline. This combination also reduced the motor coordination. Interestingly, a low dose of MPTP alone did not cause any significant reduction in the number of tyrosine hydroxylase positive neurons compared to saline treatment. Animals that received α-syn PFF and a high dose of MPTP showed massive activation of glial cells and decreased spread of α-syn, majority of which were detected in the nucleus.. Our results suggest that a combination of human WT α-syn PFF and a low dose of MPTP increases the pathological conversion and propagation of endogenous α-syn, and neurodegeneration, within a very short time. Our model can be used to study the mechanisms of α-syn propagation and screen for potential drugs against PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Corpus Striatum; Dose-Response Relationship, Drug; Injections, Intraventricular; Male; Mice; Mice, Inbred C57BL; Neurotoxins; Parkinsonian Disorders; Substantia Nigra

Parkinson's disease (PD) is a disabling progressive neurodegenerative disease. So far, PD's treatment remains symptomatic with no curative effects. Aside from its blatant analgesic and antipyretic efficacy, recent studies highlighted the endowed neuroprotective potentials of paracetamol (PCM). To this end: the present study investigated: (1) Possible protective role of PCM against rotenone-induced PD-like neurotoxicity in rats, and (2) the mechanisms underlying its neuroprotective actions including cannabinoid receptors' modulation. A dose-response study was conducted using three doses of PCM (25, 50, and 100 mg/kg/day, i.p.) and their effects on body weight changes, spontaneous locomotor activity, rotarod test, tyrosine hydroxylase (TH) and α-synuclein expression, and striatal dopamine (DA) content were evaluated. Results revealed that PCM (100 mg/kg/day, i.p.) halted PD motor impairment, prevented rotenone-induced weight loss, restored normal histological tissue structure, reversed rotenone-induced reduction in TH expression and striatal DA content, and markedly decreased midbrain and striatal α-synuclein expression in rotenone-treated rats. Accordingly, PCM (100 mg/kg/day, i.p.) was selected for further mechanistic investigations, where it ameliorated rotenone-induced oxidative stress, neuro-inflammation, apoptosis, and disturbed cannabinoid receptors' expression. In conclusion, our findings imply a multi-target neuroprotective effect of PCM in PD which could be attributed to its antioxidant, anti-inflammatory and anti-apoptotic activities, in addition to cannabinoid receptors' modulation.

Topics: Acetaminophen; alpha-Synuclein; Animals; Apoptosis; Corpus Striatum; Dopamine; Endocannabinoids; Male; Mesencephalon; Neuroprotective Agents; Oxidative Stress; Parkinsonian Disorders; Rats, Wistar; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Rotenone

Ample empirical evidence suggests that mitochondrial dysfunction and endoplasmic reticulum (ER) stress play a crucial role in the pathogenesis of Parkinson's disease (PD). Prohibitin (PHB), a mitochondrial inner-membrane protein involved in mitochondrial homeostasis and function, may be involved in the pathogenesis of PD. We investigated the functional role of PHB in mitochondrial biogenesis and ER stress in methyl-4-phenylpyridinium (MPP +)-induced in vivo and in vitro models of PD. The overexpression of PHB in SH-SY5Y cells block ed cell death and the apoptosis induced by MPP + incubation. PHB also block ed the activation of ER stress markers, including glucose-regulated protein 78, while increasing the expression of Xbox- binding protein 1 and caspase-12. Moreover, the intracerebroventricular administration of the PHB overexpression vector greatly block ed motor dysfunction and the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mediated neurodegeneration in the mouse model of PD. The production of reactive oxygen species, ER stress, and autophagic stress induced by MPTP were also significantly block ed in PD mice overexpressing PHB. Our results suggest that PHB blocks the dopaminergic-neuron depletion by preserving mitochondrial function and inhibiting ER stress. The genetic manipulation of PHB may feature potential as a treatment for PD.

Topics: alpha-Synuclein; Animals; Apoptosis; Corpus Striatum; Dopaminergic Neurons; Endoplasmic Reticulum Stress; Male; Mice; Parkinsonian Disorders; Prohibitins; Reactive Oxygen Species; Repressor Proteins; Substantia Nigra

Gene-environment interaction is implicated in the majority of idiopathic Parkinson's disease (PD) risk, and some of the most widespread environmental contaminants are selectively toxic to dopaminergic neurons. Pesticides have long been connected to PD incidence, however, it has become increasingly apparent that other industrial byproducts likely influence neurodegeneration. For example, organic solvents, which are used in chemical, machining, and dry-cleaning industries, are of growing concern, as decades of solvent use and their effluence into the environment has contaminated much of the world's groundwater and soil. Like some pesticides, certain organic solvents, such as the chlorinated halocarbon trichloroethylene (TCE), are mitochondrial toxicants, which are collectively implicated in the pathogenesis of dopaminergic neurodegeneration. Recently, we hypothesized a possible gene-environment interaction may occur between environmental mitochondrial toxicants and the protein kinase LRRK2, mutations of which are the most common genetic cause of familial and sporadic PD. In addition, emerging data suggests that elevated wildtype LRRK2 kinase activity also contributes to the pathogenesis of idiopathic PD. To this end, we investigated whether chronic, systemic TCE exposure (200 mg/kg) in aged rats produced wildtype LRRK2 activation and caused nigrostriatal dopaminergic dysfunction. Interestingly, we found that TCE not only induced LRRK2 kinase activity in the brain, but produced a significant dopaminergic lesion in the nigrostriatal tract, elevated oxidative stress, and caused endolysosomal dysfunction and α-synuclein accumulation. Together, these data suggest that TCE-induced LRRK2 kinase activity contributed to the selective toxicity of dopaminergic neurons. We conclude that gene-environment interactions between certain industrial contaminants and LRRK2 likely influence PD risk.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Dopaminergic Neurons; Endosomes; Gene-Environment Interaction; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lysosomes; Motor Activity; Neostriatum; Open Field Test; Oxidative Stress; Parkinsonian Disorders; Protein Aggregates; Rats; Solvents; Substantia Nigra; Trichloroethylene

The failure of glial cell derived neurotropic factor to be efficacious in blinded clinical trials for Parkinson's disease may be due to alterations in signaling receptors and downstream signaling molecules. To test this hypothesis, brain sections were obtained from older adults with no motor deficit (n = 6), minimal motor deficits (n = 10), and clinical diagnosis of Parkinson's disease (n = 10) who underwent motor examination proximate to death. Quantitative unbiased stereology and densitometry were performed to analyze RET and phosphorylated ribosomal protein S6 expression in nigral neurons. Individuals with no motor deficit had extensive and intense RET and phosphorylated ribosomal protein S6 immunoreactive neurons in substantia nigra. The number and staining intensity of RET-immunoreactive neurons were reduced moderately in subjects with minimal motor deficits and severely reduced in Parkinson's disease relative to no motor deficit group. The number and staining intensity of phosphorylated ribosomal protein S6 was more markedly reduced in both subjects with minimal motor deficits and Parkinson's disease. Reductions in levels of RET and phosphorylated ribosomal protein S6 were recapitulated in a non-human primate genetic Parkinson's disease model based on over-expression of human mutant α-synuclein (A53T). These data indicate that for neurotrophic factors to be effective in patients with minimal motor deficits or PD, these factors would likely have to upregulate RET and phosphorylated ribosomal protein S6 immunoreactive neurons in substantia nigra .

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Densitometry; Female; Glial Cell Line-Derived Neurotrophic Factor; Humans; Macaca fascicularis; Male; Neurturin; Parkinson Disease; Parkinsonian Disorders; Prodromal Symptoms; Proto-Oncogene Proteins c-ret; Ribosomal Protein S6; Signal Transduction

Glucagon-like peptide-1 (GLP-1) receptor stimulation ameliorates parkinsonian motor and non-motor deficits in both experimental animals and patients; however, the disease-modifying mechanisms of GLP-1 receptor activation have remained unknown. The present study investigated whether exendin-4 (a GLP-1 analogue) can rescue motor deficits and exert disease-modifying effects in a parkinsonian rat model of α-synucleinopathy. This model was established by unilaterally injecting AAV-9-A53T-α-synuclein into the right substantia nigra pars compacta, followed by 4 or 8 weeks of twice-daily intraperitoneal injections of exendin-4 (5 μg/kg/day) starting at 2 weeks after AAV-9-A53T-α-synuclein injections. Positron emission tomography/computed tomography (PET/CT) scanning and immunostaining established that treatment with exendin-4 attenuated tyrosine-hydroxylase-positive neuronal loss and terminal denervation and mitigated the decrease in expression of vesicular monoamine transporter 2 within the nigrostriatal dopaminergic systems of rats injected with AAV-9-A53T-α-synuclein. It also mitigated the parkinsonian motor deficits assessed in behavioral tests. Furthermore, through both in vivo and in vitro models of Parkinson's disease, we showed that exendin-4 promoted autophagy and mediated degradation of pathological α-synuclein, the effects of which were counteracted by 3-methyladenine or chloroquine, the autophagic inhibitors. Additionally, exendin-4 attenuated dysregulation of the PI3K/Akt/mTOR pathway in rats injected with AAV-9-A53T-α-synuclein. Taken together, our results demonstrate that exendin-4 treatment relieved behavioral deficits, dopaminergic degeneration, and pathological α-synuclein aggregation in a parkinsonian rat model of α-synucleinopathy and that these effects were mediated by enhanced autophagy via inhibiting the PI3K/Akt/mTOR pathway. In light of the safety and tolerance of exendin-4 administration, our results suggest that exendin-4 may represent a promising disease-modifying treatment for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Autophagy; Cell Line, Tumor; Exenatide; Female; Humans; Neuroprotection; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; 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 is characterized by intraneuronal α-synuclein aggregation. Currently there is no α-synuclein-based blood test in clinical practice.. Our aim was to assess by means of further testing and analysis whether α-synuclein measurements in serum L1CAM-immunocaptured exosomes can differentiate Parkinson's disease from related movement disorders.. We used poly(carboxybetaine-methacrylate)-coated magnetic beads to isolate L1CAM-positive exosomes and triplexed electrochemiluminescence to measure exosomal α-synuclein, clusterin, and syntenin-1 from 267 serum samples. Combined analysis of our current and previously published data from the Oxford, Kiel, Brescia, and PROSPECT cohorts consisting of individuals (total n = 735) with Parkinson's disease (n = 290), multiple system atrophy (MSA, n = 50), progressive supranuclear palsy (n = 116), corticobasal syndrome (n = 88), and healthy controls (n = 191) was done using 2-stage (training vs validation) receiver operating characteristic analysis.. We established that α-synuclein level in L1CAM-immunocaptured exosomes above 14 pg/mL is a robust biomarker across cohorts that distinguishes Parkinson's disease from MSA (AUC, 0.90 vs 0.98) or 4-repeat tauopathies (AUC, 0.93 vs 0.94). We confirmed that exosomal clusterin is elevated in subjects with 4-repeat tauopathy, and when combined with α-synuclein, it improved the performance of the assay in differentiating Parkinson's disease from 4-repeat tauopathies to AUC, 0.98 versus 0.99. Correction for the generic exosomal protein syntenin-1 did not consistently improve the performance of the assay.. α-Synuclein and clusterin in L1CAM-immunocaptured serum exosomes is a validated blood test for the molecular stratification of neuronal α-synucleinopathy (ie, Lewy body pathology) versus phenotypically related neurodegenerative movement disorders. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Biomarkers; Exosomes; Humans; Neural Cell Adhesion Molecule L1; Parkinsonian Disorders

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

Besides motor disorder, cognitive dysfunction is also common in Parkinson's disease (PD). Essentially no causal therapy for cognitive dysfunction of PD exists at present. In this study, a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD was used to analyze the neuroprotective potential of orally administered silibinin, a proverbial hepatoprotective flavonoid derived from the herb milk thistle (Silybum marianum). Results demonstrated that silibinin administration significantly attenuated MPTP-induced cognitive impairment in behavioral tests. Nissl staining results showed that MPTP injection significantly increases the loss of neurons in the hippocampus. However, these mice were protected by oral administration of silibinin, accompanying reduction in the cell apoptosis in the hippocampus. The hippocampal aggregates of α-synuclein (α-syn) appeared in MPTP-injected mice, but were significantly decreased by silibinin treatment. MPTP injection induced oxidative stress, as evidenced by increased malondialdehyde (MDA) and decreased superoxide dismutase (SOD). The oxidative stress was alleviated by silibinin treatment. Mitochondrial disorder including the decline of mitochondrial membrane potential (MMP) was another signature in the hippocampus of MPTP-treated mice, accompanying increased mitochondrial fission and decreased fusion. Silibinin administration restored these mitochondrial disorders, as expected for the protection against MPTP injury. These findings suggest that silibinin has a potential to be further developed as a therapeutic candidate for cognitive dysfunction in PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Administration, Oral; alpha-Synuclein; Animals; Apoptosis; Cerebral Cortex; Cognitive Dysfunction; Hippocampus; Male; Memantine; Mice, Inbred C57BL; Mitochondria; Mitochondrial Diseases; Morris Water Maze Test; Neurons; Neuroprotective Agents; Open Field Test; Oxidative Stress; Parkinsonian Disorders; Silybin

Holothuria (Metriatyla) scabra Jaeger (H. scabra), sea cucumber, is the marine organism that has been used as traditional food and medicine to gain the health benefits since ancient time. Although our recent studies have shown that crude extracts from H. scabra exhibited neuroprotective effects against Parkinson's disease (PD), the underlying mechanisms and bioactive compounds are still unknown.. In the present study, we examined the efficacy of purified compounds from H. scabra and their underlying mechanism on α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration in a transgenic Caenorhabditis elegans PD model.. The H. scabra compounds (HSEA-P1 and P2) were purified and examined for their toxicity and optimal dose-range by food-clearance and lifespan assays. The α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration were determined using transgenic C. elegans model, Punc-54::α-syn and Pdat-1:: α-syn; Pdat-1::GFP, respectively, and then further investigated by determining the behavioral assays including locomotion rate, basal slowing rate, ethanol avoidance, and area-restricted searching. The underlying mechanisms related to autophagy were clarified by quantitative PCR and RNAi experiments.. Our results showed that HSEA-P1 and HSEA-P2 significantly diminished α-synuclein accumulation, improved motility deficits, and recovered the shortened lifespan. Moreover, HSEA-P1 and HSEA-P2 significantly protected dopaminergic neurons from α-synuclein toxicity and alleviated dopamine-associated behavioral deficits, i.e., basal slowing, ethanol avoidance, and area-restricted searching. HSEA-P1 and HSEA-P2 also up-regulated autophagy-related genes, including beclin-1/bec-1, lc-3/lgg-1, and atg-7/atg-7. RNA interference (RNAi) of these genes in transgenic α-synuclein worms confirmed that lc-3/lgg-1 and atg-7/atg-7 were required for α-synuclein degradation and DAergic neuroprotection activities of HSEA-P1 and HSEA-P2. NMR and mass spectrometry analysis revealed that the HSEA-P1 and HSEA-P2 contained diterpene glycosides.. These findings indicate that diterpene glycosides extracted from H. scabra decreases α-synuclein accumulation and protects α-synuclein-mediated DAergic neuronal loss and its toxicities via lgg-1 and atg-7.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Behavior, Animal; Caenorhabditis elegans; Diterpenes; Dopaminergic Neurons; Glycosides; Holothuria; Locomotion; Nerve Degeneration; Neuroprotective Agents; Parkinsonian Disorders

Ample evidence has demonstrated that α-Synuclein can propagate from one area of the brain to others via cell-to-cell transmission, which might be the underlying mechanism for pathological propagation and the disease progression of Parkinson's disease (PD). Recent reports have demonstrated cell surface receptor-mediated cell-to-cell transmission of α-synuclein. Memantine decreased the levels of internalized cytosolic α-synuclein and led to attenuation in α-synuclein-induced cell death. Specifically, memantine attenuated α-synuclein-induced expression of clathrin and EEA1, and increased expression of NR2A subunits. Moreover, memantine inhibited propagation of extracellular α-synuclein and thus, decreased the expression of the phosphorylated form of α-synuclein in dopaminergic neurons of the substantia nigra, which was accompanied by increased survival of dopaminergic neurons with functional improvement of motor deficits. The present study demonstrated that memantine modulates extracellular α-synuclein propagation by inhibiting interactions between α-synuclein and NR2A subunits, which leads to neuroprotective effects on nigral dopaminergic neurons against α-synuclein-enriched conditions. The repositioning use of memantine in α-synuclein propagation needs to be further evaluated in patients with α-synucleinopathies as an effective therapeutic approach.

Topics: alpha-Synuclein; Animals; Cell Line; Humans; Memantine; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Parkinsonian Disorders; Receptors, N-Methyl-D-Aspartate

Cell-to-cell transmission of α-synuclein (α-syn) pathology is considered to underlie the spread of neurodegeneration in Parkinson's disease (PD). Previous studies have demonstrated that α-syn is secreted under physiological conditions in neuronal cell lines and primary neurons. However, the molecular mechanisms that regulate extracellular α-syn secretion remain unclear. In this study, we found that inhibition of monoamine oxidase-B (MAO-B) enzymatic activity facilitated α-syn secretion in human neuroblastoma SH-SY5Y cells. Both inhibition of MAO-B by selegiline or rasagiline and siRNA-mediated knock-down of MAO-B facilitated α-syn secretion. However, TVP-1022, the S-isomer of rasagiline that is 1000 times less active, failed to facilitate α-syn secretion. Additionally, the MAO-B inhibition-induced increase in α-syn secretion was unaffected by brefeldin A, which inhibits endoplasmic reticulum (ER)/Golgi transport, but was blocked by probenecid and glyburide, which inhibit ATP-binding cassette (ABC) transporter function. MAO-B inhibition preferentially facilitated the secretion of detergent-insoluble α-syn protein and decreased its intracellular accumulation under chloroquine-induced lysosomal dysfunction. Moreover, in a rat model (male Sprague Dawley rats) generated by injecting recombinant adeno-associated virus (rAAV)-A53T α-syn, subcutaneous administration of selegiline delayed the striatal formation of Ser129-phosphorylated α-syn aggregates, and mitigated loss of nigrostriatal dopaminergic neurons. Selegiline also delayed α-syn aggregation and dopaminergic neuronal loss in a cell-to-cell transmission rat model (male Sprague Dawley rats) generated by injecting rAAV-wild-type α-syn and externally inoculating α-syn fibrils into the striatum. These findings suggest that MAO-B inhibition modulates the intracellular clearance of detergent-insoluble α-syn via the ABC transporter-mediated non-classical secretion pathway, and temporarily suppresses the formation and transmission of α-syn aggregates.

Topics: alpha-Synuclein; Animals; ATP-Binding Cassette Transporters; Cell Death; Cell Line, Tumor; Corpus Striatum; Culture Media, Conditioned; Dopaminergic Neurons; Gene Knockdown Techniques; Genetic Vectors; Humans; Indans; Injections; Lysosomes; Male; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Mutation, Missense; Neuroblastoma; Parkinsonian Disorders; Protein Aggregation, Pathological; Protein Transport; Rats; Rats, Sprague-Dawley; Recombinant Proteins; RNA, Small Interfering; Selegiline; Substantia Nigra

Histone deacetylase 6 (HDAC6) has been shown to control major cell response pathways to the cytotoxic ubiquitinated aggregates in some protein aggregation diseases. However, it is not well known whether HDAC6 affects the aggregation process of α-synuclein (α-syn) in Parkinson's disease (PD). Previously, we demonstrated that HDAC6 inhibition exacerbated the nigrostriatal dopamine neurodegeneration and up-regulated α-syn oligomers in a heat shock protein 90 (Hsp90)-dependent manner in PD mouse model. Here, we further showed that HDAC6 overexpression partly improved the behavior deficits of the PD model and alleviated the nigrostriatal dopamine (DA) neurons injury. Furthermore, HDAC6 was found to regulate α-syn oligomers levels through activation of chaperone-mediated autophagy (CMA). During this process, Hsp90 deacetylation mediated the crosstalk between HDAC6 and lysosome-associated membrane protein type 2A. Liquid chromatography-tandem mass spectrometry and mutational analysis showed that acetylation status Hsp90 at the K489 site was a strong determinant for HDAC6-induced CMA activation, α-syn oligomers levels, and cell survival in the cell model of PD. Therefore, our findings uncovered the mechanism of HDAC6 in the PD model that HDAC6 regulated α-syn oligomers levels and DA neurons survival partly through modulating CMA, and Hsp90 deacetylation at the K489 site mediated the crosstalk between HDAC6 and CMA. HDAC6 and its downstream effectors appear as key modulators of the cytotoxic α-syn aggregates, which deserve further investigations to evaluate their values as potential therapeutic targets in PD.

Topics: Acetylcysteine; alpha-Synuclein; Animals; Chaperone-Mediated Autophagy; Histone Deacetylase 6; HSP90 Heat-Shock Proteins; Humans; Male; Mice; Mice, Inbred C57BL; Parkinsonian Disorders; Protein Aggregates

Gut microbiota is closely related to the Parkinson's disease (PD) pathogenesis. Additionally, aggregation of α-synuclein (α-syn) is central to PD pathogenesis. Here we identified the further mechanisms of gut microbiota in PD. A mouse model with PD was established via injection of MPTP. Normal or MPTP-induced PD like animals were treated with FMT from healthy normal mice. Pole test and traction test were performed to examine the effects of FMT on motor function of PD mice. Fecal SCFAs were assessed by gas chromatography-mass spectrometry. The α-syn level in the substantia nigra pars compacta (SN) of mice was measured using western blot. Dopaminergic neurons and microglial activation in the SN were analyzed by immunohistochemistry (IHC) and immunofluorescence (IF) staining. FMT alleviated physical impairment, decreased fecal SCFAs in a mouse model of PD. Additionally, FMT decreased the expression of α-syn, as well as inhibited the activation of microglia in the SN, and blocked the TLR4/PI3K/AKT/NF-κB signaling in the SN and striatum. FMT could protect mice against PD via suppressing α-syn expression and inactivating the TLR4/PI3K/AKT/NF-κB signaling.

Topics: alpha-Synuclein; Animals; Fecal Microbiota Transplantation; Male; Mice; Mice, Inbred C57BL; Neuroprotection; NF-kappa B; Parkinsonian Disorders; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Toll-Like Receptor 4

A hallmark feature of Parkinson's disease (PD) is the build-up of α-synuclein protein aggregates throughout the brain; however α-synuclein is also expressed in enteric neurons. Gastrointestinal (GI) symptoms and pathology are frequently reported in PD, including constipation, increased intestinal permeability, glial pathology, and alterations to gut microbiota composition. α-synuclein can propagate through neuronal systems but the site of origin of α-synuclein pathology, whether it be the gut or the brain, is still unknown. Physical exercise is associated with alleviating symptoms of PD and with altering the composition of the gut microbiota.. This study investigated the effects of bilateral nigral injection of adeno-associated virus (AAV)-α-synuclein on enteric neurons, glia and neurochemistry, the gut microbiome, and bile acid metabolism in rats, some of whom were exposed to voluntary exercise.. Nigral overexpression of α-synuclein resulted in significant neuronal loss in the ileal submucosal plexus with no change in enteric glia. In contrast, the myenteric plexus showed a significant increase in glial expression, while neuronal numbers were maintained. Concomitant alterations were observed in the gut microbiome and related bile acid metabolism. Voluntary running protected against neuronal loss, increased enteric glial expression, and modified gut microbiome composition in the brain-injected AAV-α-synuclein PD model.. These results show that developing nigral α-synuclein pathology in this PD model exerts significant alterations on the enteric nervous system (ENS) and gut microbiome that are receptive to modification by exercise. This highlights brain to gut communication as an important mechanism in PD pathology.

Topics: alpha-Synuclein; Animals; Enteric Nervous System; Gastrointestinal Microbiome; Genetic Vectors; Humans; Injections, Intraventricular; Male; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Substantia Nigra; Transfection

Preclinical studies underlined the relevance of Nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor pathway in the pathogenesis of Parkinson's disease (PD).. The objective of this study was to explore Nrf2 pathway in vivo in PD, looking for novel disease biomarkers and therapeutic targets.. The levels of Nrf2, the downstream effectors (NAD(P)H dehydrogenase [quinone] 1 (Nqo1) enzyme, glutathione metabolism enzymes Glutamate-cysteine ligase (GCL) and Glutathione Reductase (GR)), the upstream activators (redox state and mitochondrial dysfunction), and α-synuclein oligomers were assessed in the blood leukocytes of PD patients comparatively to controls. Biochemical data were correlated to clinical parameters.. In PD, Nrf2 was highly transcribed and expressed as well as its target effectors. The mitochondrial complex I activity was reduced and the oxidized form of glutathione prevailed, disclosing the presence of pathway's activators. Also, α-synuclein oligomers levels were increased. Nrf2 transcript and oligomers levels correlated with PD duration.. Blood leukocytes mirror pathogenic mechanisms of PD, showing the systemic activation of the Nrf2 pathway and its link with synucleinopathy and clinical events. © 2019 International Parkinson and Movement Disorder Society.

Topics: Adult; Aged; alpha-Synuclein; Animals; Glutathione; Humans; Male; Middle Aged; NF-E2-Related Factor 2; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Reactive Oxygen Species; Signal Transduction

Identification of a peripheral biomarker is a major roadblock in the diagnosis of PD. Immunohistological identification of p-serine 129 α-synuclein in the submandibular gland tissues of PD patients has been recently reported.. We report on a proof-of-principle study for using an ultra-sensitive and specific, real-time quaking-induced conversion assay to detect pathological α-synuclein in the submandibular gland tissues of PD patients.. The α-synuclein real-time quaking-induced conversion assay was used to detect and quantify pathological α-synuclein levels in PD, incidental Lewy body disease, and control submandibular gland tissues as well as in formalin-fixed paraffin-embedded sections.. We determined the quantitative seeding kinetics of pathological α-synuclein present in submandibular gland tissues from autopsied subjects using the α-synuclein real-time quaking-induced conversion assay. A total of 32 cases comprising 13 PD, 3 incidental Lewy body disease, and 16 controls showed 100% sensitivity and 94% specificity. Interestingly, both PD and incidental Lewy body disease tissues showed 100% concordance for elevated levels of pathological α-synuclein seeding activity compared to control tissues. End-point dilution kinetic analyses revealed that the submandibular gland had a wide dynamic range of pathological α-synuclein seeding activity.. Our results are the first to demonstrate the utility of using the real-time quaking-induced conversion assay on peripherally accessible submandibular gland tissues and formalin-fixed paraffin-embedded tissue sections to detect PD-related pathological changes with high sensitivity and specificity. Additionally, the detection of seeding activity from incidental Lewy body disease cases containing immunohistochemically undetected pathological α-synuclein demonstrates the α-synuclein real-time quaking-induced conversion assay's potential utility for identifying prodromal PD in submandibular gland tissues. © 2019 International Parkinson and Movement Disorder Society.

Topics: Aged; alpha-Synuclein; Autopsy; Biomarkers; Female; Humans; Lewy Body Disease; Male; Middle Aged; Parkinson Disease; Parkinsonian Disorders; Submandibular Gland

Dopaminergic (DAergic) degeneration and abnormal α-synuclein (α-syn) expression, phosphorylation and aggregation are observed in both the nigrostriatal system (NSS) and enteric nervous system (ENS) of patients with Parkinson's disease (PD). Whether these alterations in α-syn and DAergic neurons occur synchronously in the two nervous systems or follow a process that spreads from the gut to the brain remains a subject of debate. Here, in MPTP-intoxicated cynomolgus monkeys, we showed a parallel DAergic degeneration in the colon as well as in the substantia nigra and striatum (SN/STR), as indicated by reduced expression of tyrosine hydroxylase (TH) and dopamine transporter (DAT). In addition, we observed a simultaneous increase in the concentrations of total, phosphorylated, and oligomeric α-syn in the colon and SN/STR. Moreover, we identified that the above changes in α-syn were associated with an increase in the expression of polo-like kinase 2 (PLK2), an enzyme that promotes α-syn phosphorylation, and a decrease in the activity of protein phosphatase 2A (PP2A), an enzyme that facilitates α-syn dephosphorylation. Because the colonic ENS can be readily analyzed using routine biopsies, the shared pathological features between the colonic ENS and the brain NSS found in this study provide useful information for assessing and understanding the neuropathology in PD patients using colonic biopsies.

Topics: alpha-Synuclein; Animals; Brain; Dopaminergic Neurons; Enteric Nervous System; Macaca fascicularis; Male; Nerve Degeneration; Parkinsonian Disorders

Parkinson's disease (PD) is pathologically characterized by intraneuronal α-synuclein (α-Syn) aggregates called Lewy bodies (LBs) as well as the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). On the basis of autopsy studies, Braak et al. hypothesized that Lewy pathology initially occurs in the enteric nervous system, subsequently spreading to the dorsal motor nucleus of the vagus nerve (dmX) and then ascending in the brainstem to the SNpc. However, this hypothetical progression lacks adequate experimental evidence. We previously reported that inoculation of α-Syn preformed fibrils (PFFs) into the gastric wall of wild-type (WT) mice induced LB-like α-Syn aggregates in the dmX via the vagus nerve. However, α-Syn pathology did not spread beyond the dmX up to 12 months postinoculation. In the present study, we inoculated α-Syn PFFs into the gastric wall of bacterial artificial chromosome (BAC) transgenic mice harboring the human α-Syn gene with an A53 T mutation and analyzed the pathology. The transgenic mice had ∼1.5-fold overexpression of α-Syn in the brains and ∼6-fold overexpression of α-Syn in the stomach compared with WT mice. After inoculation of α-Syn PFFs, the transgenic mice developed a higher number of phosphorylated α-Syn (p-α-Syn)-positive neurons in the dmX compared with similarly inoculated WT mice. However, the number of p-α-Syn-positive neurons in the dmX decreased over time, and α-Syn pathology was not observed in other brain regions except in the ambiguous nucleus up to 8 months postinoculation. Taken together, BAC transgenic expression of α-Syn facilitated induction of α-Syn pathology in the brainstem, but not subsequent caudo-rostral spread in accordance with Braak's hypothesis.

Topics: alpha-Synuclein; Animals; Brain Stem; Chromosomes, Artificial, Bacterial; Enteric Nervous System; Humans; Mice; Mice, Transgenic; Parkinsonian Disorders; Stomach; Vagus Nerve

The main pathological hallmark of Parkinson's disease (PD) is the presence of Lewy bodies, which mainly consist of aggregated α-synuclein. Based on the neurotoxicity of oligomeric α-synuclein and its significance in the aetiology of PD, there has been decades of effort to elucidate an enzyme specifically degrading oligomeric α-synuclein. Here we report an enzyme, Omi, which specifically recognizes and precisely degrades oligomeric α-synuclein but not monomeric α-synuclein. After enzymatic and functional analyses of Omi in in vitro, we developed an in vivo assay system of dual gene interaction in Drosophila to investigate further the etiological role of Omi in PD. Pan-neuronal expression of Omi rescued Parkinsonism in a Drosophila model of PD, while Knockout of Omi exacerbated Parkinsonism. Expression of Omi counteracted the α-synuclein-induced retinal degeneration, providing additional evidence for Omi's protective role oligomeric α-synuclein. This work reports identification of the catabolic pathway of oligomeric α-synuclein as well as showing how Omi functions as the key molecule in the recognition and degradation of toxic oligomeric α-synuclein, a possible cause of neurodegeneration in PD, without affecting monomeric α-synuclein which is a native essential molecule for the normal function of neurons.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Animals, Genetically Modified; Drosophila melanogaster; Drosophila Proteins; Female; High-Temperature Requirement A Serine Peptidase 2; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neuroprotection; Parkinsonian Disorders

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

Mutations in the GBA1 gene are the most common genetic risk factor for Parkinson's disease (PD) and dementia with Lewy bodies (DLB). GBA1 encodes the lysosomal lipid hydrolase glucocerebrosidase (GCase), and its activity has been linked to accumulation of α-synuclein. The current study systematically examines the relationship between GCase activity and both pathogenic and non-pathogenic forms of α-synuclein in primary hippocampal, cortical, and midbrain neuron and astrocyte cultures, as well as in transgenic mice and a non-transgenic mouse model of PD. We find that reduced GCase activity does not result in aggregation of α-synuclein. However, in the context of extant misfolded α-synuclein, GCase activity modulates neuronal susceptibility to pathology. Furthermore, this modulation does not depend on neuron type but rather is driven by the level of pathological α-synuclein seeds. This study has implications for understanding how GBA1 mutations influence PD pathogenesis and provides a platform for testing novel therapeutics.

Topics: alpha-Synuclein; Animals; Astrocytes; Cerebral Cortex; Disease Susceptibility; Genetic Predisposition to Disease; Glucosylceramidase; HEK293 Cells; Hippocampus; Humans; Lewy Body Disease; Mesencephalon; Mice; Mice, Transgenic; Neurons; Parkinson Disease; Parkinsonian Disorders; Primary Cell Culture; Protein Aggregation, Pathological; Synucleinopathies

To explore the function of miR-30b in pathogenesis of Parkinson's disease (PD) and its underlying molecular mechanism.. We used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPP(+)) as a tool for constructing the PD cell model, using miR-30b mimics or inhibitors to manipulate miR-30b level for an experimental model of acquisition. The cell viability of SH-SY5Y was detected by CCK, and luciferase was used to screen the binding of target genes. The protein levels of SNCA were measured by Western blot. Then, we investigate the changes in pro- and anti-apoptotic markers with or without miR-30b treatment.. There was a significant low expression of MiR-30b in MPP(+)-induced cells. SH-SY5Y cell viability was rescued by MiR-30b overexpression. Luciferase experiments showed that MiR-30b may bind to the 3'-UTR side of SNCA and inhibited its expression. By Western blot, the SNCA level was markedly decreased by miR-30b. miR-30b attenuated the upregulation of Bax and the depletion of Bcl-2 induced by MPP(+).

Topics: 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Apoptosis; Cell Line, Tumor; Cell Survival; Dopaminergic Neurons; HEK293 Cells; Humans; MicroRNAs; Parkinsonian Disorders; Proto-Oncogene Proteins c-bcl-2; Up-Regulation

Human and animal studies have shown that exposure to the organochlorine pesticide dieldrin is associated with increased risk of Parkinson's disease (PD). Previous work showed that developmental dieldrin exposure increased neuronal susceptibility to MPTP toxicity in male C57BL/6 mice, possibly via changes in dopamine (DA) packaging and turnover. However, the relevance of the MPTP model to PD pathophysiology has been questioned. We therefore studied dieldrin-induced neurotoxicity in the α-synuclein (α-syn)-preformed fibril (PFF) model, which better reflects the α-syn pathology and toxicity observed in PD pathogenesis. Specifically, we used a "two-hit" model to determine whether developmental dieldrin exposure increases susceptibility to α-syn PFF-induced synucleinopathy. Dams were fed either dieldrin (0.3 mg/kg, every 3-4 days) or vehicle corn oil starting 1 month prior to breeding and continuing through weaning of pups at postnatal day 22. At 12 weeks of age, male and female offspring received intrastriatal α-syn PFF or control saline injections. Consistent with the male-specific increased susceptibility to MPTP, our results demonstrate that developmental dieldrin exposure exacerbates PFF-induced toxicity in male mice only. Specifically, in male offspring, dieldrin exacerbated PFF-induced motor deficits on the challenging beam and increased DA turnover in the striatum 6 months after PFF injection. However, male offspring showed neither exacerbation of phosphorylated α-syn aggregation (pSyn) in the substantia nigra (SN) at 1 or 2 months post-PFF injection, nor exacerbation of PFF-induced TH and NeuN loss in the SN 6 months post-PFF injection. Collectively, these data indicate that developmental dieldrin exposure produces a male-specific exacerbation of synucleinopathy-induced behavioral and biochemical deficits. This sex-specific result is consistent with both previous work in the MPTP model, our previously reported sex-specific effects of this exposure paradigm on the male and female epigenome, and the higher prevalence and more severe course of PD in males. The novel two-hit environmental toxicant/PFF exposure paradigm established in this project can be used to explore the mechanisms by which other PD-related exposures alter neuronal vulnerability to synucleinopathy in sporadic PD.

Topics: alpha-Synuclein; Animals; Dieldrin; Dopamine; Female; Male; Mice, Inbred C57BL; Motor Activity; Parkinsonian Disorders; Pesticides; Protein Aggregation, Pathological; Sex Factors; Substantia Nigra

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

A number of publications have reported that cysteamine has significant therapeutic effects on several aspects of Parkinson's disease (PD)-related pathology but none of these studies have evaluated its impact on pathological forms of α-Synuclein (α-Syn), one of the main hallmarks of PD. We therefore tested the efficacy of cysteamine on the Thy1-α-Syn mouse model which over-expresses full-length human wild-type α-Syn. Two-month (early stage disease) and 6-month old (late stage disease) mice and littermate controls were treated daily with cysteamine (20 mg/kg, i.p.) to assess the protective and restorative properties of this compound. After 6 weeks of treatment, animals were tested using a battery of motor tests. Cysteamine-treated transgenic mice displayed significant improvements in motor performance as compared to saline-treated transgenic littermates. Post-mortem readouts revealed a reduction in fibrillation, phosphorylation and total levels of overexpresed human α-Syn. To determine if such outcomes extended to human cells, the benefits of cysteamine were additionally tested using 6-hydroxydopamine (6-OHDA) treated neurons differentiated from induced pluripotent stem cells (iPSCs) derived from a PD patient harbouring a triplication of the SNCA gene. SNCA neurons treated with cysteamine exhibited significantly more intact/healthy neurites than cells treated with 6-OHDA alone. Additionally, SNCA neurons treated with cysteamine in the absence of 6-OHDA showed a trend towards lower total α-Syn levels. Overall, our in vivo and in vitro findings suggest that cysteamine can act as a disease-modifying molecule by enhancing -the survival of dopaminergic neurons and reducing pathological forms of α-Syn.

Topics: alpha-Synuclein; Animals; Cysteamine; Dopaminergic Neurons; Humans; Induced Pluripotent Stem Cells; Locomotion; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinsonian Disorders

Microglial function is vital for maintaining the health of the brain, and their activation is an essential component of neurodegeneration. There is significant research on factors that provoke "reactive" or "inflammatory" phenotypes in conditions of injury or disease. One such factor, exposure to the aggregated or oligomeric forms of α-synuclein, an abundant brain protein, plays an essential role in driving microglial activation; including chemotactic migration and production of inflammatory mediators in Lewy body (LB) diseases such as Parkinson's disease. On the other hand, it is increasingly recognized that microglia also undergo changes, dependent on the cellular environment, that promote mainly reconstructive and anti-inflammatory functions, i.e., mostly desirable functions of microglia in a physiological state. What maintains microglia in this physiological state is essentially unknown.. In this study, using in vitro and in vivo models, we challenged primary microglia or BV2 microglia with LPS + IFN-γ, IL-4 + IL-13, α-synuclein monomer, and α-synuclein oligomer, and examined microglia phenotype and the underlying mechanism by RT-PCR, Western blot, ELISA, IF, IHC, Co-IP.. We described a novel physiological function of α-synuclein, in which it modulates microglia toward an anti-inflammatory phenotype by interaction with extracellular signal-regulated kinase (ERK) and recruitment of the ERK, nuclear factor kappa B (NF-κB), and peroxisome proliferator-activated receptor γ (PPARγ) pathways.. These findings suggest a previously unrecognized function of monomeric α-synuclein that likely gives new insights into the pathogenesis and potential therapies for Lewy body-related diseases and beyond, given the abundance and multiple functions of α-synuclein in brain tissue.

Topics: alpha-Synuclein; Animals; Cell Line; Cell Polarity; Cells, Cultured; Immunologic Factors; Mice; Mice, 129 Strain; Mice, Inbred ICR; Mice, Knockout; Mice, Transgenic; Microglia; Parkinsonian Disorders

Currently, there is no established biomarker for Parkinson's disease (PD) and easily accessible biomarkers are crucial for developing disease-modifying treatments.. To develop a novel method to quantify cerebrospinal fluid (CSF) levels of α-synuclein protofibrils (α-syn PF) and apply it to clinical cohorts of patients with PD and atypical parkinsonian disorders.. A cohort composed of 49 patients with PD, 12 with corticobasal degeneration (CBD), 22 with progressive supranuclear palsy, and 33 controls, that visited the memory clinic but had no biomarker signs of Alzheimer's disease (AD, tau<350 pg/mL, amyloid-beta 42 (Aβ42)>530 pg/mL, and phosphorylated tau (p-tau)<60 pg/mL) was used in this study. The CSF samples were analyzed with the Single molecule array (Simoa) technology. Total α-synuclein (α-syn) levels were analyzed with a commercial ELISA-kit.. The assay is specific to α-syn PF, with no cross-reactivity to monomeric α-syn, or the β- and γ-synuclein variants. CSF α-syn PF levels were increased in PD compared with controls (62.1 and 40.4 pg/mL, respectively, p = 0.03), and CBD (62.1 and 34.2 pg/mL, respectively, p = 0.02). The accuracy of predicting PD using α-syn PF is significantly different from controls (area under the curve 0.68, p = 0.0097) with a sensitivity of 62.8% and specificity of 67.7%. Levels of total α-syn were significantly different between the PD and CBD groups (p = 0.04).. The developed method specifically quantifies α-syn PF in human CSF with increased concentrations in PD, but with an overlap with asymptomatic elderly controls.

Topics: Aged; alpha-Synuclein; Biomarkers; Female; Humans; Immunoassay; Male; Middle Aged; Parkinson Disease; Parkinsonian Disorders; Supranuclear Palsy, Progressive

The pathologic hallmark of Parkinson's disease is the accumulation of α-synuclein-containing Lewy bodies/neurites almost exclusively in neurons, and rarely in glial cells. However, emerging evidence suggests that glia such as astrocytes play an important role in the development of α-synuclein pathology. Using induced pluripotent stem-derived dopaminergic neurons and astrocytes from healthy subjects and patients carrying mutations in lysosomal

Topics: Adult; alpha-Synuclein; Astrocytes; Coculture Techniques; Dopaminergic Neurons; Exosomes; Female; Humans; Induced Pluripotent Stem Cells; Lysosomes; Male; Neuroglia; Parkinsonian Disorders; Proton-Translocating ATPases; Synucleinopathies

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

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

Many studies report a higher risk for Parkinson's disease (PD) and younger age of onset in men. This, and the fact that the neuropathological process underlying PD symptoms may begin before menopause, suggests that estrogen-based hormone therapy could modify this higher risk in males. However, the effects of female sex or estrogen on α-synuclein (αS) homeostasis and related PD neuropathology remain unknown. Here, we used an αS tetramer-abrogating mouse model of PD (3K) that amplifies the familial E46K PD mutation to investigate the effects of female sex and brain-selective estrogen treatment on αS tetramerization and solubility, formation of vesicle-rich αS

Topics: alpha-Synuclein; Animals; Brain; Estradiol; Estrogens; Female; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinsonian Disorders; Sex Characteristics

Parkinson's disease (PD) is characterised pathologically by degeneration of the dopaminergic (DA) neurones of the substantia nigra pars compacta (SNpc) and the presence of α-synuclein containing Lewy body inclusions. Trichloroethylene (TCE) has been suggested as a potential environmental chemical that may contribute to the development of PD, via conversion to the neurotoxin, 1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo). We investigated the effect of an 8 week exposure to TCE or TaClo on wild type and, as an experimental model of PD, A30P mutant α-synuclein overexpressing mice using a combination of behaviour and pathology. TCE or TaClo exposure caused significant DA neuronal loss within the SNpc in both wild type and transgenic mice. Cell numbers were lower in A30P animals than wild type, however, no additive effect of TCE or TaClo exposure and A30P overexpression was found. TCE or TaClo did not appear to lead to acceleration of motor or cognitive deficits in either wild type or A30P mutant mice, potentially because of the modest reductions of DA neuronal number in the SNpc. Our results do however suggest that TCE exposure could be a possible factor in development of PD like changes following exposure.

Topics: alpha-Synuclein; Animals; Dopaminergic Neurons; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nerve Degeneration; Neurotoxins; Parkinsonian Disorders; Substantia Nigra; Trichloroethylene

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

Alzheimer's and Parkinson's diseases are one of the world's leading causes of death. >50 million people throughout the world are suffering with these diseases. They are two distinct progressive neurodegenerative disorders affecting different regions of the brain with diverse symptoms, including memory and motor loss respectively, but with the advancement of diseases, both affect the whole brain and exhibit some common biological symptoms. For instance, >50% PD patients develop dementia in their later stages, though it is a hallmark of Alzheimer's disease. In fact, latest research has suggested the involvement of some common pathophysiological and genetic links between these diseases, including the deposition of pathological Aβ, Tau, and α-synuclein in both the cases. Therefore, it is pertinent to diagnose the shared biomarkers, their aggregation mechanism, their intricate relationships in the pathophysiology of disease and therapeutic markers to target them. This would enable us to identify novel markers for the early detection of disease and targets for the future therapies. Herein, we investigated molecular aspects of Aβ, Tau, and α-Synuclein aggregation, and characterized their functional partners involved in the pathology of AD and PD. Moreover, we identified the molecular-crosstalk between AD and PD associated with their pathogenic proteins- Aβ, Tau, and α-Synuclein. Furthermore, we characterized their ubiquitinational enzymes and associated interaction network regulating the proteasomal clearance of these pathological proteins.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Brain; Databases, Protein; Humans; Parkinsonian Disorders; Protein Aggregates; tau Proteins; Ubiquitin-Protein Ligases

Topics: Adult; Age of Onset; Aged; alpha-Synuclein; Humans; Manganese; Middle Aged; Occupational Exposure; Parkinsonian Disorders; Trace Elements; Welding

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

Aggregation of α-synuclein (α-syn) is neuropathologically and genetically linked to Parkinson's disease (PD). Since stereotypic cell-to-cell spreading of α-syn pathology is believed to contribute to disease progression, immunotherapy with antibodies directed against α-syn is considered a promising therapeutic approach for slowing disease progression. Here we report the identification, binding characteristics, and efficacy in PD mouse models of the human-derived α-syn antibody BIIB054, which is currently under investigation in a Phase 2 clinical trial for PD. BIIB054 was generated by screening human memory B-cell libraries from healthy elderly individuals. Epitope mapping studies conducted using peptide scanning, X-ray crystallography, and mutagenesis show that BIIB054 binds to α-syn residues 1-10. BIIB054 is highly selective for aggregated forms of α-syn with at least an 800-fold higher apparent affinity for fibrillar versus monomeric recombinant α-syn and a strong preference for human PD brain tissue. BIIB054 discriminates between monomers and oligomeric/fibrillar forms of α-syn based on high avidity for aggregates, driven by weak monovalent affinity and fast binding kinetics. In efficacy studies in three different mouse models with intracerebrally inoculated preformed α-syn fibrils, BIIB054 treatment attenuated the spreading of α-syn pathology, rescued motor impairments, and reduced the loss of dopamine transporter density in dopaminergic terminals in striatum. The preclinical data reported here provide a compelling rationale for clinical development of BIIB054 for the treatment and prevention of PD.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Humans; Mice; Parkinsonian Disorders; Phenotype; Protein Aggregates

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

The aim of this study is to investigate the protective effect of epigallocatechin-3-gallate (EGCG) on apoptosis and mTOR/AKT/GSK-3β pathway in substantia nigra neurons in 6-dopamine-induced Parkinson rats. A total of 30 healthy male SD rats were randomly divided into control group, the Parkinson model group, and Parkinson model+EGCG treatment group. The model and EGCG groups were injected into the right striatum with 6-OHDA to establish the Parkinson model, and the control group was injected with saline only. The EGCG group was intragastrically administered with EGCG 50 mg/kg daily for 4 weeks. The rats' turns, speed, and left forelimb usage; neuron apoptosis by TUNEL; and the α-synuclein protein expression in substantia nigra by immunohistochemical staining were studied. Western blotting was used to detect the relative protein (mTOR, AKT and GSK-3β) expressions. Compared with the model group, the EGCG group significantly reduced the rotation speed; increased the left forelimb usage (P<0.01); reduced the neuron apoptosis (P<0.01); decreased α-synuclein expression (P<0.01); and decreased the mTOR, AKT, and GSK-3β protein expressions (P<0.01). EGCG can reduce neuron cell apoptosis in substantia nigra neurons in 6-OHDA-induced Parkinson rats. The mechanism might be related to mTOR/AKT/GSK-3β activation.

Topics: alpha-Synuclein; Animals; Apoptosis; Catechin; Glycogen Synthase Kinase 3 beta; Male; Neuroprotective Agents; Parkinsonian Disorders; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Substantia Nigra; TOR Serine-Threonine Kinases; Treatment Outcome

Parkinson's disease (PD) is one of the widely reported neurodegenerative disorders affecting more than ten million people worldwide. Due to therapeutic limitations and several adverse effects associated with currently used drugs, it is crucial to search for safe and effective options for treatment of PD. Oxidative stress, mitochondrial dysfunction, α-synuclein oligomeric aggregates, and glucocerebrosidase (GCase) deficiency are involved in PD pathogenesis. Rebamipide, an anti-ulcer drug, is a proven free-radical scavenger and antioxidant. The drug has shown neuroprotective effects in cultured SH-SY5Y cells. Therefore, we investigated the pharmacological effect of rebamipide in 6-hydroxydopamine (6-OHDA)-induced experimental PD model. Rebamipide was given to adult male albino rats of Charles-Foster strain in 20, 40, and 80 mg/kg (R-20, R-40, and R-80) oral dose twice daily for 24 days (day 4 to day 27) after 6-OHDA intrastriatal injection. The drug inhibited 6-OHDA-induced motor deficits and nigral α-synuclein aggregates in dose-dependent manner. R-40 and R-80 dose dependently increased striatal mitochondrial complex I, II, IV, and V activities; mitochondrial bioenergetics; and nigral GCase activity. 6-OHDA-induced lipid peroxidation was decreased. Highest dose (R-80) also decreased apoptotic proteins and upregulated striatal dopamine concentration in 6-OHDA-induced hemiparkinson's rat model. Therefore, the anti-PD effect of rebamipide may involve stabilization of mitochondrial bioenergetics, enhancement of GCase enzymatic activity as well as decreased oxidative stress with α-synuclein pathology, and apoptosis in 6-OHDA-induced hemiparkinson's rat model. Hence, preclinical evidence indicates rebamipide to be a potential drug for management of PD.

Topics: Administration, Oral; Alanine; alpha-Synuclein; Animals; Antioxidants; Antiparkinson Agents; Apoptosis; Dose-Response Relationship, Drug; Energy Metabolism; Functional Laterality; Male; Mitochondria; Motor Activity; Neuroprotective Agents; Oxidative Stress; Parkinsonian Disorders; Quinolones; Random Allocation; Rats; Substantia Nigra

Aquaporin-4 (AQP4), the main water-selective membrane transport protein in the brain, is localized to the astrocyte plasma membrane. Following the establishment of a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) model, AQP4-deficient (AQP4

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Aquaporin 4; Astrocytes; Cell Line, Transformed; Dopamine; Gene Expression Regulation; Inflammation; Male; Mesencephalon; Mice; Mice, Knockout; Neuroglia; Neurons; Neurotoxins; Parkinsonian Disorders; Primary Cell Culture; Probenecid; Signal Transduction; Transforming Growth Factor beta1; Tyrosine 3-Monooxygenase

Adult-onset neurodegenerative disorders, like Parkinson's disease (PD) and dementia with Lewy bodies (DLB), that share the accumulation of aggregated α-synuclein (αSyn

Topics: Age Factors; Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Animals; Benzothiazoles; Biomarkers; Brain Chemistry; Case-Control Studies; Computer Systems; Fluorescent Dyes; Fluorometry; High-Throughput Screening Assays; Humans; Lewy Body Disease; Mice; Microglia; Middle Aged; Neuroglia; Parkinsonian Disorders; Protein Aggregates; Recombinant Proteins; Reproducibility of Results; Sensitivity and Specificity; Single-Blind Method; Synucleinopathies

A reliable biomarker is needed for accurate and early differentiation between Parkinson disease and the various forms of atypical parkinsonism. We used a novel real-time quaking-induced conversion (RT-QuIC) assay to detect α-synuclein (α-syn) aggregates in cerebrospinal fluid (CSF) of 118 patients with parkinsonism of uncertain clinical etiology and 52 controls. Diagnostic accuracy to distinguish α-synucleinopathies from non-α-synucleinopathies and controls was 84% (sensitivity = 75%, specificity = 94%, area under the curve = 0.84, 95% confidence interval = 0.78-0.91, p < 0.0001, positive predictive value = 93%). CSF α-syn RT-QuIC could be a useful diagnostic tool to help clinicians differentiate α-synucleinopathies from other forms of parkinsonism when the clinical picture is uncertain. Ann Neurol 2019;85:777-781.

Topics: Aged; alpha-Synuclein; Biomarkers; Cohort Studies; Diagnosis, Differential; Female; Follow-Up Studies; Humans; Male; Middle Aged; Parkinsonian Disorders; Prospective Studies

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

This study investigated the expression and role of immunoproteasome (i-proteasome) in a cell model of Parkinson's disease (PD). The cytotoxicity of rotenone was measured by CCK-8 assay. The i-proteasome β1i subunit PSMB9 was suppressed by a specific shRNA or transfected with an overexpression plasmid in the SH-SY5Y cells. Under the exposure to rotenone or not, the expression of constitutive proteasome β subunits, i-proteasome βi subunits, antigen presentation related proteins, α-syn and TH were detected by Western blot in PSMB9-silenced or -overexpressed cells, and the proteasomal activities were detected by fluorogenic peptide substrates. The location of i-proteasome βi subunits and α-syn were detected by immunofluorescence staining. The levels of ROS, GSH and MDA were measured by commercial kits. Cell apoptosis was detected by flow cytometry. Besides impairing the constitutive proteasomes, rotenone induced the expression of βi subunits of i-proteasome and antigen presentation related proteins such as TAP1, TAP2 and MHC-I. Silencing or overexpressing PSMB9 had no obvious effect on the levels of other subunits, but could regulate the chymotrypsin-like activity of 20S proteasome and the expression of TAP1, TAP2 and MHC-I. Three βi subunits (PSMB9, PSMB10, PSMB8) of i-proteasome were all co-localized with α-syn. PSMB9 knockdown aggravated accumulation of α-syn, degradation of TH, release of ROS, increased level of MDA, decreased level of GSH and eventually promoted apoptosis in SH-SY5Y cells after rotenone treatment, while over-expression of PSMB9 could attenuate these toxic effects of rotenone. I-proteasome is activated in SH-SY5Y cells treated with rotenone and may play a neuroprotective role.

Topics: alpha-Synuclein; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 2; ATP Binding Cassette Transporter, Subfamily B, Member 3; Cell Line, Tumor; Cysteine Endopeptidases; Gene Expression Regulation; Histocompatibility Antigens Class I; Humans; Neurons; Oxidative Stress; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Rotenone; Signal Transduction; 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 (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

To investigate the prevalence of clinically relevant multiple system atrophy (MSA) and Lewy body disease (LBD) pathologies in a large frontotemporal lobar degeneration (FTLD) cohort to determine if concomitant pathologies underlie the heterogeneity of clinical features.. All prospectively followed FTLD-tau and FTLD-TDP cases held by the Sydney Brain Bank (n = 126) were screened for coexisting MSA and LBD (Braak ≥ stage IV) pathology. Relevant clinical (including family history) and genetic associations were determined.. MSA pathology was not identified in this series. Of the FTLD cohort, 9 cases had coexisting LBD ≥ Braak stage IV and were associated with different FTLD subtypes including Pick disease (n = 2), corticobasal degeneration (n = 2), progressive supranuclear palsy (n = 2), and TDP type A (n = 3). All FTLD-TDP cases with coexisting LBD had mutations in. Coexisting LBD in FTLD comprises a small proportion of cases but has implications for clinical and neuropathologic diagnoses and the identification of biomarkers.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Brain; C9orf72 Protein; DNA-Binding Proteins; Female; Frontotemporal Lobar Degeneration; Humans; Lewy Body Disease; Male; Middle Aged; Multiple System Atrophy; Parkinsonian Disorders; Prevalence; Progranulins; tau Proteins

Parkinson's disease (PD) is a common neurodegenerative disease characterized by progressive dopaminergic neurodegeneration with a concomitant increase in oxidative stress and neuroinflammation in the substantia nigra pars compacta (SNc). Recent studies have focused on targeting neuroinflammation and oxidative stress to effectively treat PD. The present study evaluated the neuroprotective effect of thymoquinone (TQ) against 1-methyl-4-phenyl 1,2,3,6 tetrahydropyridine (MPTP)-induced oxidative stress and neuroinflammation in a PD mouse model. TQ (10 mg/kg body weight [b. wt.]) was administered for 1 week prior to MPTP (25 mg/kg b. wt.). MPTP administration caused oxidative stress as evidenced by decreased activities of superoxide dismutase and catalase, a depletion of reduced glutathione, and a concomitant rise in malondialdehyde. It also significantly increased pro-inflammatory cytokines and elevated inflammatory mediators such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the striatum. Immunohistochemical analysis revealed dopamine neuron loss in the SNc and decreased dopamine transporters in the striatum following MPTP administration; however, these were rescued by TQ treatment. TQ treatment further restored antioxidant enzymes, prevented glutathione depletion, inhibited lipid peroxidation, and attenuated pro-inflammatory cytokines. TQ also decreased the raised levels of inflammatory mediators, such as COX-2 and iNOS. Therefore, TQ is thought to protect against MPTP-induced PD and the observed neuroprotective effects are attributed to its potent antioxidant and anti-inflammatory properties. Moreover, the in vitro analysis found that TQ significantly inhibited α-synuclein aggregation and prevented cell death induced by pre-formed fibrils. Thus, TQ not only scavenges the MPTP-induced toxicity but also prevents α-synuclein-fibril formation and its associated toxicity.

Topics: alpha-Synuclein; Animals; Benzoquinones; Cell Line, Tumor; Corpus Striatum; Humans; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Parkinsonian Disorders; Protein Aggregates

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 is a key player in the pathogenesis of Parkinson disease (PD). Expression of human heme oxygenase-1 (HO-1) in astrocytes of GFAP.HMOX1 transgenic (TG) mice between 8.5 and 19 months of age results in a parkinsonian phenotype characterized by neural oxidative stress, nigrostriatal hypodopaminergia associated with locomotor incoordination, and overproduction of α-synuclein. We identified two microRNAs (miR-), miR-153 and miR-223, that negatively regulate α-synuclein in the basal ganglia of male and female GFAP.HMOX1 mice. Serum concentrations of both miRNAs progressively declined in the wild-type (WT) and GFAP.HMOX1 mice between 11 and 19 months of age. Moreover, at each time point surveyed, circulating levels of miR-153 were significantly lower in the TG animals compared to WT controls, while α-synuclein protein concentrations were elevated in erythrocytes of the GFAP.HMOX1 mice at 19 months of age relative to WT values. Primary WT neurons co-cultured with GFAP.HMOX1 astrocytes exhibited enhanced protein oxidation, mitophagy and apoptosis, aberrant expression of genes regulating the dopaminergic phenotype, and an imbalance in gene expression profiles governing mitochondrial fission and fusion. Many, but not all, of these neuronal abnormalities were abrogated by small interfering RNA (siRNA) knockdown of α-synuclein, implicating α-synuclein as a potent, albeit partial, mediator of HO-1's neurodystrophic effects in these parkinsonian mice. Overexpression of HO-1 in stressed astroglia has previously been documented in the substantia nigra of idiopathic PD and may promote α-synuclein production and toxicity by downmodulating miR-153 and/or miR-223 both within the CNS and in peripheral tissues.

Topics: alpha-Synuclein; Animals; Apoptosis; Brain; Cells, Cultured; Coculture Techniques; Erythrocytes; Female; Gene Expression; Heme Oxygenase-1; Humans; Male; Membrane Proteins; Mice, Transgenic; MicroRNAs; Mitochondria; Neuroglia; Neurons; Oxidative Stress; Parkinsonian Disorders

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

Topics: alpha-Synuclein; Cross-Sectional Studies; Humans; Parkinson Disease; Parkinsonian Disorders

Because of the highly penetrant gene mutation and clinical features consistent with idiopathic Parkinson's disease, carriers of the autosomal dominant Ala53Thr (A53T; 209G→A) point mutation in the α-synuclein (SNCA) gene are an ideal population to study the premotor phase and evolution of Parkinson's pathology. Given the known neurochemical changes in the serotonergic system and their association with symptoms of Parkinson's disease, we hypothesised that carriers of the A53T SNCA mutation might show abnormalities in the serotonergic neurotransmitter system before the diagnosis of Parkinson's disease, and that this pathology might be associated with measures of Parkinson's burden.. In this cross-sectional study, we recruited carriers of the A53T SNCA mutation from specialist Movement Disorders clinics in Athens, Greece, and Salerno, Italy, and a cohort of healthy controls with no personal or family history of neurological or psychiatric disorders from London, UK (recruited via public advertisement) who were age matched to the A53T SNCA carriers. We also recruited one cohort of patients with idiopathic Parkinson's disease (cohort 1) from Movement Disorders clinics in London, UK, and retrieved data on a second cohort of such patients (cohort 2; n=40) who had been scanned with a different scanner. 7-day continuous recording of motor function was used to determine the Parkinson's disease status of the A53T carriers. To assess whether serotonergic abnormalities were present, we used [. Between Sept 1, 2016, and Sept 30, 2018, we recruited 14 A53T SNCA carriers, 25 healthy controls, and 25 patients with idiopathic Parkinson's disease. Seven (50%) of 14 A53T SCNA carriers were confirmed to have motor symptoms and confirmed to have Parkinson's disease, and the absence of motor symptoms was confirmed in seven (50%) A53T SCNA carriers (ie, premotor), in whom [. The presence of serotonergic pathology in premotor A53T SNCA carriers preceded development of dopaminergic pathology and motor symptoms and was associated with disease burden, highlighting the potential early role of serotonergic pathology in the progression of Parkinson's disease. Our findings provide evidence that molecular imaging of serotonin transporters could be used to visualise premotor pathology of Parkinson's disease in vivo. Future work might establish whether serotonin transporter imaging is suitable as an adjunctive tool for screening and monitoring progression for individuals at risk or patients with Parkinson's disease to complement dopaminergic imaging, or as a marker of Parkinson's burden in clinical trials.. Lily Safra Hope Foundation and National Institute for Health Research (NIHR) Biomedical Research Centre at King's College London.

Topics: Adult; Aged; alpha-Synuclein; Brain; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Parkinsonian Disorders; Serotonin; Serotonin Plasma Membrane Transport Proteins; Severity of Illness Index

Analysis of human pathology led Braak to postulate that α-synuclein (α-syn) pathology could spread from the gut to brain via the vagus nerve. Here, we test this postulate by assessing α-synucleinopathy in the brain in a novel gut-to-brain α-syn transmission mouse model, where pathological α-syn preformed fibrils were injected into the duodenal and pyloric muscularis layer. Spread of pathologic α-syn in brain, as assessed by phosphorylation of serine 129 of α-syn, was observed first in the dorsal motor nucleus, then in caudal portions of the hindbrain, including the locus coeruleus, and much later in basolateral amygdala, dorsal raphe nucleus, and the substantia nigra pars compacta. Moreover, loss of dopaminergic neurons and motor and non-motor symptoms were observed in a similar temporal manner. Truncal vagotomy and α-syn deficiency prevented the gut-to-brain spread of α-synucleinopathy and associated neurodegeneration and behavioral deficits. This study supports the Braak hypothesis in the etiology of idiopathic Parkinson's disease (PD).

Topics: alpha-Synuclein; Animals; Axonal Transport; Brain Chemistry; Dopaminergic Neurons; Duodenum; Humans; Injections, Intramuscular; Lewy Bodies; Maze Learning; Memory Disorders; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Neurological; Muscle, Smooth; Nesting Behavior; Parkinsonian Disorders; Phosphorylation; Protein Aggregates; Protein Processing, Post-Translational; Pylorus; Rotarod Performance Test; Vagotomy; Vagus Nerve

Early diagnosis of Parkinson's disease (PD) is of great importance due its progressive phenotype. Neuroprotective drugs could potentially slow down disease progression if used at early stages. Previously, we have reported an altered content of volatile organic compounds (VOCs) in the breath of rats following a 50% reduction in striatal dopamine (DA) content induced by 6-hydroxydopamine. We now report on the difference in the breath-print and content of VOCs between rats with mild and severe lesions of DA neurons, serotonergic neuronal lesions, and transgenic (Tg) rats carrying the PD-producing A53T mutation of the SNCA (α-synuclein) gene. The Tg rats had an increased content of 3-octen-1-ol and 4-chloro-3-methyl phenol in blood, while in brain tissue, hexanal, hexanol, and 2,3-octanedione were present in controls but absent in Tg rats. Levels of 1-heptyl-2-methyl cyclopropane were increased in brain tissue of Tg rats. The data confirm the potential of breath analysis for detection of human idiosyncratic as well as autosomal dominant PD.

Topics: 5,7-Dihydroxytryptamine; alpha-Synuclein; Animals; Breath Tests; Corpus Striatum; Discriminant Analysis; Dopaminergic Neurons; Factor Analysis, Statistical; Male; Mutation; Oxidopamine; Parkinsonian Disorders; Rats, Sprague-Dawley; Rats, Transgenic; Serotonergic Neurons; Volatile Organic Compounds

Recently, the incidence of Parkinson's disease has shown a tendency to move to a younger population, linked to the constantly increasing stressors of modern society. However, this relationship remains obscure. Here, we have investigated the contribution of stress and the mechanisms underlying this change.. Ten-month-old α-synuclein A53T mice, a model of Parkinson's disease (PD), were treated with chronic restraint stress (CRS) to simulate a PD-sensitive person with constant stress stimulation. PD-like behavioural tests and pathological changes were evaluated. Differentiated PC12-A53T cells were treated with corticosterone in vitro. We used Western blot, microRNA expression analysis, immunofluorescence staining, dual luciferase reporter assay and HPLC electrochemical detection to assess cellular and molecular networks after stress treatment. In vivo, stereotaxic injection of shRNA lentivirus was used to confirm our in vitro results.. The protein RTP801 is encoded by DNA-damage-inducible transcript 4, and it was specifically increased in dopaminergic neurons of the substantia nigra after CRS treatment. RTP801 was post-transcriptionally inhibited by the down-regulation of miR-7. Delayed turnover of RTP801, through the inhibition of proteasome degradation also contributed to its high content. Elevated RTP801 blocked autophagy, thus increasing accumulation of oligomeric α-synuclein and aggravating endoplasmic reticulum stress. RTP801 inhibition alleviated the symptoms of neurodegeneration during this process.. RTP801 is a promising target for the treatment of PD, especially for PD-sensitive patients who live under increased social pressure. Down-regulation of RTP801 could inhibit the current tendency to an earlier onset of PD.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Animals; DNA-Binding Proteins; Humans; Male; Mice; Mice, Transgenic; Neurodegenerative Diseases; Parkinsonian Disorders; PC12 Cells; Rats; Restraint, Physical; Stress, Psychological; Transcription Factors

Serum response factor (SRF), a transcription factor highly expressed in neurons, is involved in neuronal survival and the pathogenesis of some neurodegenerative disorders. The ablation of SRF renders the midbrain dopaminergic (DA) neurons vulnerable to 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine-induced neurotoxicity, however, the underlying mechanisms remain poorly understood. Here, we report decreased SRF levels in the substantia nigra (SN) of rotenone-treated rats that was associated with the loss of tyrosine hydroxylase (TH)-positive neurons. SRF expression was also reduced in rotenone-treated PC12 cells in vitro. In addition, Srf knockdown augmented rotenone-induced toxicity in PC12 cells. In contrast, overexpression of Srf attenuated the cells' sensitivity to rotenone and alleviated rotenone-induced α-synuclein accumulation. The protective effect of SRF was abolished when the expression of autophagy-related proteins Beclin 1 and Atg5 was suppressed. These results suggested that SRF may promote DA neuron survival by regulating autophagy, and thus serves as a critical molecule in PD progression.

Topics: alpha-Synuclein; Animals; Autophagy; Autophagy-Related Protein 5; Beclin-1; Cell Survival; Dopaminergic Neurons; Male; Parkinsonian Disorders; PC12 Cells; Random Allocation; Rats; Rats, Inbred Lew; Rotenone; Substantia Nigra; Transcription Factors; Tyrosine 3-Monooxygenase

Numerous long non-coding RNAs (lncRNAs) have been identified as aberrantly expressed in Parkinson's disease (PD). However, limited knowledge is available concerning the roles of dysregulated lncRNAs and the underlying molecular regulatory mechanism in the pathological process of PD. In this study, we found that lncRNA small nucleolar RNA host gene 1 (SNHG1) and seven in absentia homolog 1 (SIAH1) were upregulated, but microRNA-15b-5p (miR-15b-5p) was downregulated in SH-SY5Y cells pretreated with MPP+, as well as in MPTP-induced mouse model of PD. Overexpression of SIAH1 enhanced cellular toxicity of α-synuclein in SH-SY5Y cells, as indicated by the reduction of cell viability and elevation of LDH release. The percentage of α-synuclein aggregate-positive cells and the number of α-synuclein aggregates per cell were increased in SH-SY5Y cells transfected with pcDNA-SIAH1, while decreased after transfection with short interfering RNA specific for SIAH1 (si-SIAH1). Bioinformatics and luciferase reporter assay revealed that SIAH1 was a direct target of miR-15b-5p. We also found that SNHG1 could directly bind to miR-15-5p and repress miR-15-5p expression. Upregulation of miR-15b-5p alleviated α-synuclein aggregation and apoptosis by targeting SIAH1 in SH-SY5Y cells overexpressing α-synuclein. Overexpression of SNHG1 enhanced, whereas SNHG1 knockdown inhibited α-synuclein aggregation and α-synuclein-induced apoptosis. Moreover, the neuroprotective effect of si-SNHG1 was abrogated by downregulation of miR-15b-5p. In summary, our data suggest that SNHG1, as a pathogenic factor, promotes α-synuclein aggregation and toxicity by targeting the miR-15b-5p/SIAH1 axis, contributing to a better understanding of the mechanisms of Lewy body formation and loss of dopaminergic neurons in PD.

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Gene Expression Regulation; Male; Mice, Inbred C57BL; MicroRNAs; Nuclear Proteins; Parkinson Disease; Parkinsonian Disorders; Protein Aggregation, Pathological; RNA, Long Noncoding; Ubiquitin-Protein Ligases

Growing evidence suggests, as Parkinson's disease (PD) progresses, that its non-motor symptoms appear prior to or in parallel with its motor deficits. Alpha-synuclein A53T transgenic mouse (A53T) is an essential tool to investigate the onsets and the extents of PD non-motor symptoms. Our aim is to investigate spatial learning and memory ability in A53T mice. In our rotarod tests, no motor coordination impairments were detected in mice of 3, 6, 9, and 12 months old. We then investigated their spatial learning and memory ability through Morris water maze in 3- and 9-month-old mice. No significant difference in escape latency was detected among the A53T mice and the control mice. However, an unexpected improvement in spatial learning and memory ability was observed in the probe session among the A53T mice. Reversal learning by Morris water maze also indicated that 3- and 9-month-old A53T mice exhibited a better cognitive flexibility compared to their littermate controls. Further studies by western blots showed that alpha-synuclein expressions in hippocampus of the A53T mice were noticeably up-regulated. The immunofluorescence staining of 5-bromo-2-deoxyuridine (Brdu) and doublecortin (DCX) demonstrated that neither the Brdu-positive neurons nor the Brdu/DCX positive neurons in hippocampus were significantly altered between the two groups. These results suggest that our A53T mice exhibit improved spatial learning and memory ability prior to their motor coordination deficits. These results are not induced by neurogenesis in the hippocampus.

Topics: alpha-Synuclein; Animals; Doublecortin Protein; Humans; Memory; Mice; Mice, Transgenic; Parkinsonian Disorders; Spatial Learning

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

The p. A53T mutation in the alpha-synuclein (SNCA) gene is a rare cause of autosomal dominant Parkinson's disease (PD). Although generally rare, it is particularly common in the Greek population due to a founder effect. A53T-positive PD patients often develop dementia during disease course and may very rarely present with dementia.. We screened for the p. A53T SNCA mutation a total of 347 cases of Greek origin with parkinsonism and/or dementia, collected over 15 years at the Neurogenetics Unit, Eginition Hospital, University of Athens. Cases were classified into: "pure parkinsonism", "pure dementia" and "parkinsonism plus dementia".. In total, 4 p. A53T SNCA mutation carriers were identified. All had autosomal dominant family history and early onset. Screening of the "pure parkinsonism" category revealed 2 cases with typical PD. The other two mutation carriers were identified in the "parkinsonism plus dementia" category. One had a diagnosis of PD dementia and the other of behavioral variant frontotemporal dementia. Screening of patients with "pure dementia" failed to identify any further A53T-positive cases.. Our results confirm that the p. A53T SNCA mutation is relatively common in Greek patients with PD or PD plus dementia, particularly in cases with early onset and/or autosomal dominant family history.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Dementia; Female; Gene Expression; Greece; Humans; Male; Middle Aged; Mutation; Parkinsonian Disorders; Pedigree; Phenotype

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

Dysfunction of mitophagy, which is a selective degradation of defective mitochondria for quality control, is known to be implicated in the pathogenesis of Parkinson's disease (PD). However, how treadmill exercise (TE) regulates mitophagy-related molecules in PD remains to be elucidated. Therefore, we aimed to investigate how TE regulates α-synuclein (α-syn)-induced neurotoxicity and mitophagy-related molecules in the nigro-striatal region of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mice. Our data showed that TE exhibited a significant restoration of tyrosine hydroxylase and motor coordination with suppression of α-syn expression, hallmarks of PD, possibly via up-regulation of lysosomal degradation molecules, LAMP-2 and cathepsin L, with down-regulation of p62, LC3-II/LC3-I ratio, PINK1 and parkin in the substantia nigra of MPTP mice. Therefore, these results suggest that treadmill exercise can be used as a non-invasive intervention to improve the pathological features and maintain a healthier mitochondrial network through appropriate elimination of defective mitochondria in PD.

Topics: alpha-Synuclein; Animals; Blotting, Western; Corpus Striatum; Gene Expression Regulation; Immunohistochemistry; Lysosomes; Mice; Motor Activity; Neuroprotection; Parkinsonian Disorders; Physical Conditioning, Animal; Substantia Nigra; Tyrosine 3-Monooxygenase

Mutations in glucocerebrosidase (GBA) cause Gaucher disease (GD) and increase the risk of developing Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB). Since both genetic and environmental factors contribute to the pathogenesis of sporadic PD, we investigated the susceptibility of nigrostriatal dopamine (DA) neurons in L444P GBA heterozygous knock-in (GBA. We used GBA. L444P GBA heterozygous mutation reduced GBA protein levels, enzymatic activity and a concomitant accumulation of α-synuclein in the midbrain of GBA. Our results suggest that GBA deficiency due to L444P GBA heterozygous mutation and the accompanying accumulation of α-synuclein render DA neurons more susceptible to MPTP intoxication. Thus, GBA and α-synuclein play dual physiological roles in the survival of DA neurons in response to the mitochondrial dopaminergic neurotoxin, MPTP.

Topics: alpha-Synuclein; Animals; Dopaminergic Neurons; Gene Knock-In Techniques; Glucosylceramidase; Humans; Mesencephalon; Mice; Mice, Knockout; Mutation; Nerve Degeneration; Parkinsonian Disorders

Topics: alpha-Synuclein; Attention Deficit Disorder with Hyperactivity; Biogenic Amines; Diagnosis, Differential; Dystonia; Homozygote; Humans; Intellectual Disability; Molecular Chaperones; Parkinsonian Disorders; Phenylketonurias; Protein Aggregation, Pathological; Proteostasis; Repressor Proteins

Parkinson's disease (PD) is a result of the loss of dopaminergic neurons in the substantia nigra and is expected to increase the economic burden on patients' families and societies. NEAT1, a long non-coding RNA, is known as a cancer-related gene, however, the role of it in PD remains unclear. The aims of this study are to detect the NEAT1-mediated effects in PD and explore the mechanism of NEAT1 in PD. One group (n = 6) of C57BL/6 model mice were intraperitoneal injected with 1-Methyl-4-phenyl-2, 3, 6-tetrahydropyridine (MPTP), while another group (n = 6) was treated with saline and served as control. Human neuroblastoma cell line SH-SY5Y was pretreated with 1-Methyl-4-phenylpyridinium (MPP+). Cell viability and apoptosis, as well as gene expression with different treatments were examined. Up-regulated NEAT1 was found in MPTP-induced PD mice. Moreover, the NEAT1 expression was positively correlated with the concentration of MPP+. In SH-SY5Y cells stimulated by MPP+, NEAT1 knockdown dramatically promoted cell viability and suppressed cell apoptosis. Additionally, down-regulation of NEAT1 also decreased the ratio of Bax/Bcl-2, the activity of caspase-3, as well as the expression of α-synuclein. Moreover, α-synuclein overexpression could significantly reverse the increase in cell viability and the decrease in cell apoptosis induced by NEAT1 knockdown. The results suggested that the knockdown of NEAT1 will have a protective effect on MPTP-induced PD mice. The mechanism may be related to the dysregulation of α-synuclein.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Apoptosis; Brain; Cell Line, Tumor; Cell Survival; Dopaminergic Neurons; Gene Expression Regulation; Gene Knockdown Techniques; Humans; Male; Mice; Mice, Inbred C57BL; Parkinsonian Disorders; RNA, Long Noncoding; RNA, Small Interfering

Parkinson's disease (PD) affects motor function through degenerative processes and synaptic transmission impairments in the basal ganglia. None of the treatments available delays or stops the progression of the disease. While α-synuclein pathological accumulation represents a hallmark of the disease in its idiopathic form, leucine rich repeat kinase 2 (LRRK2) is genetically associated with familial and sporadic forms of PD. The genetic information suggests that LRRK2 kinase activity plays a role in the pathogenesis of the disease. To support a potential link between LRRK2 and α-synuclein in the pathophysiological mechanisms underlying PD, the effect of LRRK2 ablation or LRRK2 kinase pharmacological inhibition were studied in rats with adeno-associated virus-induced (AAV) α-synuclein overexpression in the nigrostriatal pathway. We first report that viral overexpression of α-synuclein induced increased burst firing in subthalamic neurons. Aberrant firing pattern of subthalamic neurons has also been reported in PD patients and neurotoxin-based animal models, and is hypothesized to play a key role in the appearance of motor dysfunction. We further report that genetic LRRK2 ablation, as well as pharmacological inhibition of LRRK2 kinase activity with PFE-360, reversed the aberrant firing pattern of subthalamic neurons induced by AAV-α-synuclein overexpression. This effect of LRRK2 modulation was not associated with any neuroprotective effect or motor improvement. Nonetheless, our findings may indicate a potential therapeutic benefit of LRRK2 kinase inhibition by normalizing the aberrant neuronal activity of subthalamic neurons induced by AAV-α-synuclein, a neurophysiological trait recapitulating observations in PD.

Topics: Action Potentials; alpha-Synuclein; Animals; Dependovirus; Female; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Parkinsonian Disorders; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Rats, Transgenic; Subthalamic Nucleus

Parkinsonisms are neurodegenerative disorders characterized pathologically by α-synuclein-positive (e.g., PD, diffuse Lewy body disease, and MSA) and/or tau-positive (e.g., PSP, cortical basal degeneration) pathology. Using R2* and quantitative susceptibility mapping, susceptibility changes have been reported in the midbrain of living parkinsonian patients, although the exact underlying pathology of these alterations is unknown.. The current study investigated the pathological correlates of these susceptibility MRI measures.. In vivo MRIs (T1- and T2-weighted, and T2*) and pathology were obtained from 14 subjects enrolled in an NINDS PD Biomarker Program (PDBP). We assessed R2* and quantitative susceptibility mapping values in the SN, semiquantitative α-synuclein, tau, and iron values, as well as neuronal and glial counts. Data were analyzed using age-adjusted Spearman correlations.. R2* was associated significantly with nigral α-synuclein (r = 0.746; P = 0.003). Quantitative susceptibility mapping correlated significantly with Perls' (r = 0.758; P = 0.003), but not with other pathological measurements. Neither measurement correlated with tau or glial cell counts (r ≤ 0.11; P ≥ 0.129).. Susceptibility MRI measurements capture nigral pathologies associated with parkinsonian syndromes. Whereas quantitative susceptibility mapping is more sensitive to iron, R2* may reflect pathological aspects of the disorders beyond iron such as α-synuclein. They may be invaluable tools in diagnosing differential parkinsonian syndromes, and tracking in living patients the dynamic changes associated with the pathological progression of these disorders. © 2018 International Parkinson and Movement Disorder Society.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Brain Mapping; Correlation of Data; Disease Progression; Female; Humans; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Male; Middle Aged; Parkinsonian Disorders; Substantia Nigra; tau Proteins

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

For Parkinson's disease (PD), the regulatory mechanism of α-synuclein (α-syn) aggregation remains to be clarified. Ubiquitination modification is crucial for α-syn aggregation, with implications for Lewy body formation. Besides, ubiquitin ligase absentia homolog (siAH) is involved in the ubiquitination of α-syn. We investigated whether the p75 receptor can act as a potential regulator of α-syn accumulation through ubiquitination. Western blot, immunoprecipitation, gene transfection, and RNA interference technology were employed to detect the effect of p75 in in vivo and in vitro models. In a rotenone-based stereotactic (ST) infusion in vivo model of PD, p75 receptor and siAH expression was increased significantly compared with the control group. In cellular models of rotenone-mediated neurotoxicity, the interactions between p75 and siAH were revealed by immunoprecipitation; the colocalization of p75 with α-syn was observed in the cytoplasm; p75 promoted nuclear expression of NF-κB (p65), which might interact with the promoter of the siAH gene. Moreover, siRNA-mediated p75 depletion reduced the upregulation of α-syn and nuclear expression of p65 and protected against cell apoptosis induced by rotenone. Thus, aberrant expression of p75 may regulate the increased expression of α-syn, which is related to siAH-mediated ubiquitination and nuclear expression of p65.

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Line, Tumor; Dopaminergic Neurons; Gene Expression Regulation; Humans; Nuclear Proteins; Parkinsonian Disorders; Pars Compacta; Random Allocation; Rats, Sprague-Dawley; Receptor, Nerve Growth Factor; Rotenone; Transcription Factor RelA; Ubiquitin-Protein Ligases; Ubiquitination

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

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

Leucine-rich repeat kinase 2 (LRRK2) is the most common causative gene for autosomal dominant Parkinson's disease (PD) and is also known to be a susceptibility gene for sporadic PD. Although clinical symptoms with LRRK2 mutations are similar to those in sporadic PD, their pathologies are heterogeneous and include nigral degeneration with abnormal inclusions containing alpha-synuclein, tau, TAR DNA-binding protein 43, and ubiquitin, or pure nigral degeneration with no protein aggregation pathologies. We discovered two families harboring heterozygous and homozygous c.4332 G > A; p.R1441H in LRRK2 with consanguinity, sharing a common founder. They lived in the city of Makurazaki, located in a rural area of the southern region, the Kagoshima prefecture, in Kyushu, Japan. All patients presented late-onset parkinsonism without apparent cognitive decline and demonstrated a good response to levodopa. We obtained three autopsied cases that all presented with isolated nigral degeneration with no alpha-synuclein or other protein inclusions. This is the first report of neuropathological findings in patients with LRRK2 p.R1441H mutations that includes both homozygous and heterozygous mutations. Our findings in this study suggest that isolated nigral degeneration is the primary pathology in patients with LRRK2 p.R1441H mutations, and that protein aggregation of alpha-synuclein or tau might be secondary changes.

Topics: Aged; alpha-Synuclein; Astrocytes; Autopsy; DNA-Binding Proteins; Female; Gene Expression Regulation; Histidine; Homozygote; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Mutation; Neurodegenerative Diseases; Parkinsonian Disorders; Proline; Protein Aggregation, Pathological; Substantia Nigra; tau Proteins

SNCA mutations cause autosomal dominant parkinsonism and inform our understanding of the molecular underpinnings of synucleinopathies. The most recently identified mutation, p.Ala53Glu (A53E), has only been observed in Finland. The objectives of this study were to examine clinical, genetic, epigenetic, and biochemical features of the first family outside Finland with A53E.. We examined a Canadian family with parkinsonism because of A53E using haplotype and DNA methylation analyses. We assessed aggregation properties of A53E α-synuclein in vitro.. Family members with parkinsonism shared a common haplotype distinct from Finnish patients with A53E. Increased acceleration of DNA methylation age was accompanied by earlier age at onset in the family members. We demonstrate that A53E α-synuclein has a propensity to form oligomers and phosphorylation promotes fibrillation.. A53E as a cause of parkinsonism is not restricted to Finnish individuals. DNA methylation may contribute to disease age at onset. A53E enriches α-synuclein oligomers and fibrils dependent on the phosphorylation state. © 2018 International Parkinson and Movement Disorder Society.

Topics: Aged; alpha-Synuclein; Epigenomics; Female; Gene Expression; Haplotypes; Humans; Male; Middle Aged; Mutation; Parkinsonian Disorders; Pedigree

Autophagy is an intracellular degradation process that is involved in α-synuclein (α-syn) homeostasis and Parkinson's disease (PD). The purpose of this study was to investigate whether hydroxysafflor yellow A (HSYA) could promote α-syn clearance via regulating autophagy in PD mice. Male C57BL/6 mice were intraperitoneally treated with HSYA. Thirty minutes later, they were intragastrically administered with rotenone at a dose of 30 mg/kg. The hanging wire test was performed at 14 and 28 days. Then, autophagosomes and ultrastructural changes were examined by transmission electron microscopy. The expression of tyrosine hydroxylase (TH), α-syn, JNK1, p-JNK1, Bcl-2, p-Bcl-2, Beclin1, autophagy-related proteins (Atg) 7 and 12-5, and the LC3-II/LC3-I ratio were investigated by western blot. The hanging time of HSYA-treated PD mice was significantly increased compared with that of rotenone-induced PD mice (p < 0.05 or p < 0.01). Compared with rotenone-induced PD mice, treatment with HSYA augmented the formation of autophagosomes. The expression of TH, p-JNK1/JNK1, Beclin1, Atg7, Atg12-5, p-Bcl-2/Bcl-2, and the LC3-II/LC3-I ratio were significantly increased, whereas the expression of α-syn was reduced in the rotenone plus HSYA group. These results indicate that HSYA promoted α-syn clearance via regulating autophagy in rotenone-induced PD mice.

Topics: alpha-Synuclein; Animals; Autophagy; Brain; Chalcone; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Parkinsonian Disorders; Quinones; Rotenone; Uncoupling Agents

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

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

To our knowledge, a comprehensive study of the survival and causes of death of persons with synucleinopathies compared with the general population has not been conducted. Understanding the long-term outcomes of these conditions may inform patients and caregivers of the expected disease duration and may help with care planning.. To compare survival rates and causes of death among patients with incident, clinically diagnosed synucleinopathies and age- and sex-matched referent participants.. This population-based study used the Rochester Epidemiology Project medical records-linkage system to identify all residents in Olmsted County, Minnesota, who received a diagnostic code of parkinsonism from 1991 through 2010. A movement-disorders specialist reviewed the medical records of each individual to confirm the presence of parkinsonism and determine the type of synucleinopathy. For each confirmed patient, an age- and sex-matched Olmsted County resident without parkinsonism was also identified.. We determined the age- and sex-adjusted risk of death for each type of synucleinopathy, the median time from diagnosis to death, and the causes of death.. Of the 461 patients with synucleinopathies, 279 (60.5%) were men, and of the 452 referent participants, 272 (60.2%) were men. From 1991 through 2010, 461 individuals received a diagnosis of a synucleinopathy (309 [67%] of Parkinson disease, 81 [17.6%] of dementia with Lewy bodies, 55 [11.9%] of Parkinson disease dementia, and 16 [3.5%] of multiple system atrophy with parkinsonism). During follow-up, 68.6% (n = 316) of the patients with synucleinopathies and 48.7% (n = 220) of the referent participants died. Patients with any synucleinopathy died a median of 2 years earlier than referent participants. Patients with multiple system atrophy with parkinsonism (hazard ratio, 10.51; 95% CI, 2.92-37.82) had the highest risk of death compared with referent participants, followed by those with dementia with Lewy bodies (hazard ratio, 3.94; 95% CI, 2.61-5.94), Parkinson disease with dementia (hazard ratio, 3.86; 95% CI, 2.36-6.30), and Parkinson disease (hazard ratio, 1.75; 95% CI, 1.39-2.21). Neurodegenerative disease was the most frequent cause of death listed on the death certificate for patients, and cardiovascular disease was the most frequent cause of death among referent participants.. Individuals with multiple system atrophy with parkinsonism, dementia with Lewy bodies, and Parkinson disease dementia have increased mortality compared with the general population. The mortality among persons with Parkinson disease is only moderately increased compared with the general population.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Cause of Death; Comorbidity; Dementia; Female; Follow-Up Studies; Humans; Lewy Body Disease; Male; Middle Aged; Minnesota; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders

Parkinson's disease (PD) is characterized neuropathologically by intracellular aggregates of fibrillar α-synuclein, termed Lewy bodies (LBs). Approximately 90% of α-synuclein deposited as LBs is phosphorylated at Ser129 in brains with PD. In contrast, only 4% of total α-synuclein is phosphorylated at Ser129 in brains with normal individuals. It is unclear why extensive phosphorylation occurs in the pathological process of PD. To address this issue, we investigated a mechanism and role of Ser129-phosphorylation in regulating accumulation of α-synuclein. In CHO cells, the levels of Ser129-phosphorylated soluble α-synuclein were maintained constantly to those of total α-synuclein in intracellular and extracellular spaces. In SH-SY5Y cells and rat primary cortical neurons, mitochondrial impairment by rotenone or MPP

Topics: alpha-Synuclein; Animals; Calcium; Cations, Divalent; Cell Line, Tumor; Cerebral Cortex; CHO Cells; Cricetulus; Extracellular Space; Humans; Mutation; Neurons; Parkinsonian Disorders; Phosphorylation; Proteasome Endopeptidase Complex; Protein Aggregation, Pathological; Rats, Sprague-Dawley; Stress, Physiological

Parkinson's disease (PD) is the most common neurodegenerative movement disorder, and its causes remain unknown. A major hallmark of the disease is the increasing presence of aggregated alpha-synuclein (aSyn). Furthermore, there is a solid consensus on iron (Fe) accumulation in several regions of PD brains during disease progression. In our study, we focused on the interaction of Fe and aggregating aSyn in vivo in a transgenic mouse model overexpressing human aSyn bearing the A53T mutation (prnp.aSyn.A53T). We utilized a neonatal iron-feeding model to exacerbate the motor phenotype of the transgenic mouse model. Beginning from day 100, mice were treated with deferiprone (DFP), a ferric chelator that is able to cross the blood-brain barrier and is currently used in clinics as treatment for hemosiderosis. Our paradigm resulted in an impairment of the learning abilities in the rotarod task and the novel object recognition test. DFP treatment significantly improved the performance in both tasks. Although this was not accompanied by alterations in aSyn aggregation, our results support DFP as possible therapeutic option in PD.

Topics: alpha-Synuclein; Animals; Cell Count; Deferiprone; Drug Evaluation, Preclinical; Female; Gait Disorders, Neurologic; Humans; Iron; Iron Chelating Agents; Learning Disabilities; Male; Mice; Mice, Transgenic; Neurons; Parkinsonian Disorders; Protein Aggregation, Pathological; Pyridones; Recognition, Psychology; Rotarod Performance Test

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

Elevated iron in the SNpc may play a key role in Parkinson's disease (PD) neurodegeneration since drug candidates with high iron affinity rescue PD animal models, and one candidate, deferirpone, has shown efficacy recently in a phase two clinical trial. However, strong iron chelators may perturb essential iron metabolism, and it is not yet known whether the damage associated with iron is mediated by a tightly bound (eg ferritin) or lower-affinity, labile, iron pool. Here we report the preclinical characterization of PBT434, a novel quinazolinone compound bearing a moderate affinity metal-binding motif, which is in development for Parkinsonian conditions. In vitro, PBT434 was far less potent than deferiprone or deferoxamine at lowering cellular iron levels, yet was found to inhibit iron-mediated redox activity and iron-mediated aggregation of α-synuclein, a protein that aggregates in the neuropathology. In vivo, PBT434 did not deplete tissue iron stores in normal rodents, yet prevented loss of substantia nigra pars compacta neurons (SNpc), lowered nigral α-synuclein accumulation, and rescued motor performance in mice exposed to the Parkinsonian toxins 6-OHDA and MPTP, and in a transgenic animal model (hA53T α-synuclein) of PD. These improvements were associated with reduced markers of oxidative damage, and increased levels of ferroportin (an iron exporter) and DJ-1. We conclude that compounds designed to target a pool of pathological iron that is not held in high-affinity complexes in the tissue can maintain the survival of SNpc neurons and could be disease-modifying in PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antiparkinson Agents; Cation Transport Proteins; Cell Line, Tumor; Dogs; Female; Humans; Iron; Male; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Neuroprotective Agents; Oxidative Stress; Oxidopamine; Parkinsonian Disorders; Quinazolinones; Rats; Recombinant Proteins; Substantia Nigra

Parkinson's disease (PD) is a neurodegenerative movement disorder, which affects approximately 1-2% of the population over 60years of age. Current treatments for PD are symptomatic, and the pathology of the disease continues to progresses over time until palliative care is required. Mitochondria are key players in the pathology of PD. Genetic and post mortem studies have shown a large number of mitochondrial abnormalities in the substantia nigra pars compacta (SNc) of the parkinsonian brain. Furthermore, physiologically, mitochondria of nigral neurons are constantly under unusually high levels of metabolic stress because of the excitatory properties and architecture of these neurons. The protein deacetylase, Sirtuin 3 (SIRT3) reduces the impact subcellular stresses on mitochondria, by stabilising the electron transport chain (ETC), and reducing oxidative stress. We hypothesised that viral overexpression of myc-tagged SIRT3 (SIRT3-myc) would slow the progression of PD pathology, by enhancing the functional capacity of mitochondria. For this study, SIRT3-myc was administered both before and after viral induction of parkinsonism with the AAV-expressing mutant (A53T) α-synuclein. SIRT3-myc corrected behavioural abnormalities, as well as changes in striatal dopamine turnover. SIRT3-myc also prevented degeneration of dopaminergic neurons in the SNc. These effects were apparent, even when SIRT3-myc was transduced after the induction of parkinsonism, at a time point when cell stress and behavioural abnormalities are already observed. Furthermore, in an isolated mitochondria nigral homogenate prepared from parkinsonian SIRT3-myc infected animals, SIRT3 targeted the mitochondria, to reduce protein acetylation levels. Our results demonstrate that transduction of SIRT3 has the potential to be an effective disease-modifying strategy for patients with PD. This study also provides potential mechanisms for the protective effects of SIRT3-myc.

Topics: Acetylation; alpha-Synuclein; Animals; Cell Line, Tumor; Dependovirus; Female; Genetic Vectors; Humans; Male; Mice, Inbred C57BL; Mitochondria; Mutation; Neurons; Neuroprotection; Organelle Biogenesis; Parkinsonian Disorders; Rats, Sprague-Dawley; Sirtuin 3; Substantia Nigra

Parkinson's Disease (PD) is a complex and heterogeneous neurodegenerative disease characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta and pathological intracellular accumulation of alpha-synuclein (α-syn). In the vast majority of PD patients, the disease has a complex etiology, defined by multiple genetic and environmental risk factors. Common genetic variants in the human leukocyte-antigen (HLA) region have been associated to PD risk and the carriage of these can double the risk to develop PD. Among these common genetic variants are the ones that modulate the expression of MHCII genes. MHCII molecules encoded in the HLA-region are responsible for antigen presentation to the adaptive immune system and have a key role in inflammatory processes. In addition to cis‑variants affecting MHCII expression, a transactivator encoded by the Mhc2ta gene is the major regulator of MHCII expression. We have previously identified variations in the promoter region of Mhc2ta, encoded in the VRA4 region, to regulate MHCII expression in rats. The expression of MHCII is known to be required in the response to α-syn. However, how the expression of MHCII affects the activation of microglial or the impact of physiological, differential Mhc2ta expression on degeneration of dopaminergic neurons has not previously been addressed. Here we addressed the implications of common genetic allelic variants of the major regulator of MHCII expression on α-syn-induced microglia activation and the severity of the dopaminergic neurodegeneration. We used a viral vector technology to overexpress α-syn in two rat strains; Dark agouti (DA) wild type and DA.VRA4-congenic rats. The congenic strain carries PVG alleles in the VRA4 locus and therefore displays lower Mhc2ta expression levels compared to DA rats. We analyzed the impact of this physiological differential Mhc2ta expression on gliosis, inflammation, degeneration of the nigro-striatal dopamine system and behavioral deficits after α-syn overexpression. We report that allelic variants of Mhc2ta differently modified the microglial activation in response to overexpression of human α-syn in rats. Overexpression of α-syn led to a larger denervation of the nigro-striatal system and significant behavioral deficits in DA.VRA4 congenic rats with lower Mhc2ta expression compared to DA rats. These results indicate that Mhc2ta is a key upstream regulator of the inflammatory response in PD pathology.

Topics: Alleles; alpha-Synuclein; Animals; Corpus Striatum; Dependovirus; Dopaminergic Neurons; Genes, MHC Class II; Genetic Predisposition to Disease; Genetic Variation; Genetic Vectors; Humans; Male; Microglia; Motor Activity; Nerve Degeneration; Nuclear Proteins; Parkinsonian Disorders; Rats, Transgenic; Trans-Activators

Biallelic DNAJC12 mutations were described in children with hyperphenylalaninemia, neurodevelopmental delay, and dystonia. We identified DNAJC12 homozygous null variants (c.187A>T;p.K63* and c.79-2A>G;p.V27Wfs*14) in two kindreds with early-onset parkinsonism. Both probands had mild intellectual disability, mild nonprogressive, motor symptoms, sustained benefit from small dose of levodopa, and substantial worsening of symptoms after levodopa discontinuation. Neuropathology (Proband-A) revealed no alpha-synuclein pathology, and substantia nigra depigmentation with moderate cell loss. DNAJC12 transcripts were reduced in both patients. Our results suggest that DNAJC12 mutations (absent in 500 early-onset patients with Parkinson's disease) rarely cause dopa-responsive nonprogressive parkinsonism in adulthood, but broaden the clinical spectrum of DNAJC12 deficiency. Ann Neurol 2017;82:640-646.

Topics: Adult; alpha-Synuclein; Amyloid beta-Peptides; Antiparkinson Agents; Biogenic Amines; Brain; DNA Mutational Analysis; DNA-Binding Proteins; Family Health; Female; Humans; Levodopa; Male; Middle Aged; Mutation; Parkinsonian Disorders; Phenylalanine; Repressor Proteins; Sequestosome-1 Protein; tau Proteins; Young Adult

The protein α-synuclein (α-Syn) interferes with glucose and lipid uptake and also activates innate immune cells. However, it remains unclear whether α-Syn or its familial mutant forms contribute to metabolic alterations and inflammation in synucleinopathies, such as Parkinson's disease (PD). Here, we address this issue in transgenic mice for the mutant A53T human α-Syn (α-SynA53T), a mouse model of synucleinopathies. At 9.5 months of age, mice overexpressing α-SynA53T (homozygous) had a significant reduction in weight, exhibited improved locomotion and did not show major motor deficits compared with control transgenic mice (heterozygous). At 17 months of age, α-SynA53T overexpression promoted general reduction in grip strength and deficient hindlimb reflex and resulted in severe disease and mortality in 50 % of the mice. Analysis of serum metabolites further revealed decreased levels of cholesterol, triglycerides and non-esterified fatty acids (NEFA) in α-SynA53T-overexpressing mice. In fed conditions, these mice also showed a significant decrease in serum insulin without alterations in blood glucose. In addition, assessment of inflammatory gene expression in the brain showed a significant increase in TNF-α mRNA but not of IL-1β induced by α-SynA53T overexpression. Interestingly, the brain mRNA levels of Sirtuin 2 (Sirt2), a deacetylase involved in both metabolic and inflammatory pathways, were significantly reduced. Our findings highlight the relevance of the mechanisms underlying initial weight loss and hyperactivity as early markers of synucleinopathies. Moreover, we found that changes in blood metabolites and decreased brain Sirt2 gene expression are associated with motor deficits.

Topics: Age Factors; alpha-Synuclein; Animals; Blood Glucose; Body Weight; Brain Chemistry; Energy Metabolism; Hand Strength; Humans; Insulin; Lipids; Metabolic Networks and Pathways; Mice; Mice, Transgenic; Motor Activity; Mutation, Missense; Nerve Tissue Proteins; Parkinsonian Disorders; Point Mutation; Reflex, Abnormal; Rotarod Performance Test; Sirtuin 2; Tumor Necrosis Factor-alpha

Subcutaneous administration of rotenone has recently attracted attention because of its convenience, simplicity and efficacy in replicating features of Parkinson's disease (PD) in animal models. However, the wide range of doses reported in the literature makes it difficult to evaluate the effectiveness of this technique objectively. The aim of the present study was to identify the optimum dose of subcutaneous rotenone for establishing a model of PD. We injected male Wistar rats subcutaneously with one of three doses of rotenone (1.5, 2, or 2.5mg/kg) daily for 5 weeks. Rotenone caused a dose-dependent increase in α-synuclein in the substantia nigra. Furthermore, at 2 and 2.5mg/kg, rotenone caused a significant decrease in the number of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra, and dopamine in the striatum. However, mortality at 2.5mg/kg was 46.7%, compared with just 6.7% at 2mg/kg; the high mortality observed at 2.5mg/kg would limit its application. The 2mg/kg dose showed no detrimental effect on body weight after 5 weeks of daily injections. Furthermore, rats in the 2mg/kg group showed a longer latency to descend from a horizontal bar and a grid wall, decreased rearing, and shorter latency to fall from a rotarod than rats that received vehicle or saline. Mitochondrial damage, observed by transmission electron microscopy, was also evident at this dose. Together, our data indicate that daily subcutaneous injection of 2mg/kg rotenone in rats facilitates the formation of α-synuclein and reproduces the typical features of PD, while maintaining low mortality.

Topics: alpha-Synuclein; Animals; Body Weight; Corpus Striatum; Dopamine; Dose-Response Relationship, Drug; Injections, Subcutaneous; Male; Mitochondria; Motor Activity; Neurons; Parkinsonian Disorders; Random Allocation; Rats, Wistar; Rotarod Performance Test; Rotenone; Substantia Nigra; Tyrosine 3-Monooxygenase

Patients presenting with the classical idiopathic normal pressure hydrocephalus (iNPH) triad often show additional parkinsonian spectrum signs. Accurate differential diagnosis strongly influences the long-term outcome of cerebrospinal fluid (CSF) shunting.. The aim of this study was to find potential CSF microRNA (miRNA) biomarkers for NPH mimics with parkinsonian syndromes that can reliably distinguish them from iNPH patients.. Two cohorts of 81 patients (cohort 1, n = 55; cohort 2, n = 26) with possible iNPH who were treated in two centers between January 2011 and May 2014 were studied. In both cohorts, CSF samples were obtained from patients clinically diagnosed with iNPH (n = 21 and n = 10, respectively), possible iNPH with parkinsonian spectrum (PS) (n = 18, n = 10, respectively), possible iNPH with Alzheimer's disease (AD) (n = 16), and non-affected elderly individuals (NC) (n = 6). A three-step qRT-PCR analysis of the CSF samples was performed to detect miRNAs that were differentially expressed in the groups.. The expression of hsa-miR-4274 in CSF was decreased in both cohorts of PS group patients (cohort 1: p < 0.0001, cohort 2: p < 0.0001), and was able to distinguish PS from iNPH with high accuracy (area under the curve = 0.908). The CSF concentration of hsa-miR-4274 also correlated with the specific binding ratio of ioflupane (123I) dopamine transporter scan (r = -0.494, p = 0.044). By contrast, the level of hsa-miR-4274 was significantly increased in the PS group after CSF diversion.. Levels of CSF hsa-miR-4274 can differentiate PS from patients with iNPH, AD, and NC. This may be clinically useful for diagnostic purposes and predicting shunt treatment responses.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Cohort Studies; Female; Gene Expression Regulation; Humans; Hydrocephalus, Normal Pressure; Male; MicroRNAs; Parkinsonian Disorders; Peptide Fragments; RNA, Messenger

Nanomaterials hold significant potential for industrial and biomedical application these years. Therefore, the relationship between nanoparticles and neurodegenerative disease is of enormous interest. In this contribution, zebrafish embryos and PC12 cell lines were selected for studying neurotoxicity of titanium dioxide nanoparticles (TiO

Topics: alpha-Synuclein; Animals; Brain; Dopaminergic Neurons; Embryo, Nonmammalian; Female; Gene Expression; Larva; Male; Metal Nanoparticles; Parkinsonian Disorders; PC12 Cells; Protein Serine-Threonine Kinases; Rats; Reactive Oxygen Species; Titanium; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases; Zebrafish

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Corpus Striatum; Dependovirus; Dopamine; Dopamine Plasma Membrane Transport Proteins; Genetic Vectors; Homovanillic Acid; Humans; Male; Mice, Inbred C57BL; Motor Activity; Mutation; Nerve Degeneration; Neurons; Parkinsonian Disorders; Substantia Nigra; Tyrosine 3-Monooxygenase

α-Synuclein is a defining, key component of Lewy bodies and Lewy neurites in Parkinson's disease (PD) and dementia with Lewy bodies (DLB), as well as glial cytoplasmic inclusions in multiple system atrophy (MSA). The distribution and spreading of these pathologies are closely correlated with disease progression. Recent studies have revealed that intracerebral injection of synthetic α-synuclein fibrils or pathological α-synuclein prepared from DLB or MSA brains into wild-type or transgenic animal brains induced prion-like propagation of phosphorylated α-synuclein pathology. The common marmoset is a very small primate that is expected to be a useful model of human diseases. Here, we show that intracerebral injection of synthetic α-synuclein fibrils into adult wild-type marmoset brains (caudate nucleus and/or putamen) resulted in spreading of abundant α-synuclein pathologies, which were positive for various antibodies to α-synuclein, including phospho Ser129-specific antibody, anti-ubiquitin and anti-p62 antibodies, at three months after injection. Remarkably, robust Lewy body-like inclusions were formed in tyrosine hydroxylase (TH)-positive neurons in these marmosets, strongly suggesting the retrograde spreading of abnormal α-synuclein from striatum to substantia nigra. Moreover, a significant decrease in the numbers of TH-positive neurons was observed in the injection-side of the brain, where α-synuclein inclusions were deposited. Furthermore, most of the α-synuclein inclusions were positive for 1-fluoro-2,5-bis (3-carboxy-4-hydroxystyryl) benzene (FSB) and thioflavin-S, which are dyes widely used to visualize the presence of amyloid. Thus, injection of synthetic α-synuclein fibrils into brains of non-transgenic primates induced PD-like α-synuclein pathologies within only 3 months after injection. Finally, we provide evidence indicating that neurons with abnormal α-synuclein inclusions may be cleared by microglial cells. This is the first marmoset model for α-synuclein propagation. It should be helpful in studies to elucidate mechanisms of disease progression and in development and evaluation of disease-modifying drugs for α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Benzothiazoles; Brain; Callithrix; Female; Immunohistochemistry; Lewy Bodies; Microglia; Nerve Degeneration; Neurons; Parkinsonian Disorders; Protein Aggregation, Pathological; Recombinant Proteins; Sequence Homology, Amino Acid; Thiazoles; Tyrosine 3-Monooxygenase

Neurodegenerative parkinsonian syndromes have significant clinical and pathological overlap, making early diagnosis difficult. Cerebrospinal fluid (CSF) biomarkers may aid the differentiation of these disorders, but other than α-synuclein and neurofilament light chain protein, which have limited diagnostic power, specific protein biomarkers remain elusive.. To study disease mechanisms and identify possible CSF diagnostic biomarkers through discovery proteomics, which discriminate parkinsonian syndromes from healthy controls.. CSF was collected consecutively from 134 participants; Parkinson's disease (n = 26), atypical parkinsonian syndromes (n = 78, including progressive supranuclear palsy (n = 36), multiple system atrophy (n = 28), corticobasal syndrome (n = 14)), and elderly healthy controls (n = 30). Participants were divided into a discovery and a validation set for analysis. The samples were subjected to tryptic digestion, followed by liquid chromatography-mass spectrometry analysis for identification and relative quantification by isobaric labelling. Candidate protein biomarkers were identified based on the relative abundances of the identified tryptic peptides. Their predictive performance was evaluated by analysis of the validation set.. 79 tryptic peptides, derived from 26 proteins were found to differ significantly between atypical parkinsonism patients and controls. They included acute phase/inflammatory markers and neuronal/synaptic markers, which were respectively increased or decreased in atypical parkinsonism, while their levels in PD subjects were intermediate between controls and atypical parkinsonism.. Using an unbiased proteomic approach, proteins were identified that were able to differentiate atypical parkinsonian syndrome patients from healthy controls. Our study indicates that markers that may reflect neuronal function and/or plasticity, such as the amyloid precursor protein, and inflammatory markers may hold future promise as candidate biomarkers in parkinsonism.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Biomarkers; Cohort Studies; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Neurofilament Proteins; Parkinsonian Disorders; Proteomics

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common genetic cause of Parkinson's disease. Here, we investigated whether the G2019S LRRK2 mutation causes morphological and/or functional changes at nigro-striatal dopamine neurons. Density of striatal dopaminergic terminals, nigral cell counts, tyrosine hydroxylase protein levels as well as exocytotic dopamine release measured in striatal synaptosomes, or striatal extracellular dopamine levels monitored by in vivo microdialysis were similar between ≥12-month-old G2019S knock-in mice and wild-type controls. In vivo striatal dopamine release was insensitive to the LRRK2 inhibitor Nov-LRRK2-11, and was elevated by the membrane dopamine transporter blocker GBR-12783. However, G2019S knock-in mice showed a blunted neurochemical and motor activation response to GBR-12783 compared to wild-type controls. Western blot and dopamine uptake analysis revealed an increase in dopamine transporter levels and activity in the striatum of 12-month-old G2019S KI mice. This phenotype correlated with a reduction in vesicular monoamine transporter 2 levels and an enhancement of vesicular dopamine uptake, which was consistent with greater resistance to reserpine-induced hypolocomotion. These changes were not observed in 3-month-old mice. Finally, Western blot analysis revealed no genotype difference in striatal levels of endogenous α-synuclein or α-synuclein bound to DOPAL (a toxic metabolite of dopamine). However, Serine129-phosphorylated α-synuclein levels were higher in 12-month-old G2019S knock-in mice. Immunohistochemistry confirmed this finding, also showing no genotype difference in 3-month-old mice. We conclude that the G2019S mutation causes progressive dysfunctions of dopamine transporters, along with Serine129-phosphorylated α-synuclein overload, at striatal dopaminergic terminals, which are not associated with dopamine homeostasis dysregulation or neuron loss but might contribute to intrinsic dopaminergic terminal vulnerability. We propose G2019S knock-in mice as a presymptomatic Parkinson's disease model, useful to investigate the pathogenic interaction among genetics, aging, and internal or environmental factors leading to the disease.

Topics: Aging; alpha-Synuclein; Animals; Corpus Striatum; Dopamine; Dopamine Plasma Membrane Transport Proteins; Gene Knock-In Techniques; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Parkinsonian Disorders; Phenotype; Phosphorylation; Prodromal Symptoms; Substantia Nigra; Vesicular Monoamine Transport Proteins

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 a multisystem disorder, involving several monoaminergic neurotransmitter systems resulting in a broad range of motor and non-motor symptoms. Pathological hallmarks of PD are the loss of dopaminergic neurons and the accumulation of alpha-synuclein, however also being present in the serotonergic raphe nuclei early in the disease course. The dysfunction of the serotonergic system projecting to the hippocampus may contribute to early non-motor symptoms such as anxiety and depression. The adult hippocampal dentate gyrus (DG), a unique niche of the forebrain continuously generating new neurons, may particularly present enhanced susceptibility towards accumulating alpha-synuclein levels. The underlying molecular mechanisms in the context of neuronal maturation and survival of new-born neurons are yet not well understood. To characterize the effects of overexpression of human full-length alpha-synuclein on hippocampal cellular and synaptic plasticity, we used a recently generated BAC alpha-synuclein transgenic rat model showing important features of PD such as widespread and progressive alpha-synuclein aggregation pathology, dopamine loss and age-dependent motor decline. At the age of four months, thus prior to the occurrence of the motor phenotype, we observed a profoundly impaired dendritogenesis of neuroblasts in the hippocampal DG resulting in severely reduced survival of adult new-born neurons. Diminished neurogenesis concurred with a serotonergic deficit in the hippocampus as defined by reduced levels of serotonin (5-HT) 1B receptor, decreased 5-HT neurotransmitter levels, and a loss of serotonergic nerve terminals innervating the DG/CA3 subfield, while the number of serotonergic neurons in the raphe nuclei remained unchanged. Moreover, alpha-synuclein overexpression reduced proteins involved in vesicle release, in particular synapsin-1 and Rab3 interacting molecule (RIM3), in conjunction with an altered ultrastructural architecture of hippocampal synapses. Importantly, BAC alpha-synuclein rats showed an early anxiety-like phenotype consisting of reduced exploratory behavior and feeding. Taken together, these findings imply that accumulating alpha-synuclein severely affects hippocampal neurogenesis paralleled by impaired 5-HT neurotransmission prior to the onset of aggregation pathology and overt motor deficits in this transgenic rat model of PD.

Topics: alpha-Synuclein; Animals; Blotting, Western; Bromodeoxyuridine; Cell Count; Dopamine; Dorsal Raphe Nucleus; Doublecortin Domain Proteins; Exploratory Behavior; Feeding Behavior; Fluorescent Antibody Technique; Hippocampus; Humans; Male; Microscopy, Electron; Microtubule-Associated Proteins; Neurogenesis; Neurons; Neuropeptides; Parkinsonian Disorders; Rats, Transgenic; Serotonin; Synapses

Microglia activation and inflammatory factors in brain microenvironment are associated with degeneration of neurons in the substantia nigra (SN) of Parkinson's disease (PD) patients and various PD models. There is increasing evidence that the Rho/ROCK (Rho kinase) signalling pathway may play a critical role in the inflammatory response, and ROCK inhibitor has been reported to have neuroprotective effects. In this study, we examined the neuroprotective potential and possible mechanism of ROCK inhibitor Fasudil in an intranasal lipopolysaccharide (LPS)-induced PD model. ROCK was activated with LPS stimulation and inhibited by Fasudil treatment in this PD model. Behavioural tests demonstrated a clear improvement in motor performance after Fasudil treatment. Furthermore, Fasudil resulted in a significant attenuation of dopamine cell loss, α-synuclein accumulation and inflammatory response with the reversion of inflammatory M1 to anti-inflammatory M2 microglia, decreased NF-кB activation, and IL-12 and TNF-α generation in the SN and olfactory bulb in this model. This study establishes a role for Fasudil in protecting against LPS-mediated dopamine degeneration and provides a therapeutic strategy for the treatment of PD.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Administration, Intranasal; alpha-Synuclein; Animals; Dopaminergic Neurons; Encephalitis; Female; Inflammation Mediators; Lipopolysaccharides; Mice, Inbred C57BL; Microglia; Motor Activity; Neuroprotective Agents; NF-kappa B; Olfactory Bulb; Parkinsonian Disorders; rho-Associated Kinases; Signal Transduction; Substantia Nigra

Levodopa-induced dyskinesia (LID) is a disabling complication of levodopa therapy in Parkinson's disease (PD) with no effective treatments. Fluctuations in levels of levodopa constitute a key risk factor of LID. There is a pressing need for the development of a simple animal model of LID. Several genetic and toxin-based models of PD in Caenorhabditis elegans have been described, which have advanced our understanding of PD pathophysiology. We aimed to study levodopa-induced changes in a Parkinson's disease model of C. elegans expressing human α-synuclein.. We exposed the α-synuclein C. elegans to levodopa in continuous and alternating fashions. Automated behavioral analysis was then used to quantify changes in motor activity. Confocal microscopy was used next to quantify changes in dopamine receptor distribution and expression in motor neurons of live C. elegans.. Chronic exposure to levodopa led to hyperactivity of the α-synuclein C. elegans without meaningful increase in motor activity. There was also an increase in peripheral clustering and expression of dopamine receptors in motor neurons. Both of these changes were significantly higher with alternating, compared to continuous, exposure to levodopa.. This is the first report of changes in motor and dopamine receptors induced by levodopa in C. elegans overexpressing human α-synuclein. We propose that these phenotypes represent a simple animal model of LID in C. elegans. Such a model holds the promise of enabling high-throughput screenings for potential therapeutic targets and drug candidates.

Topics: Actigraphy; alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Caenorhabditis elegans; Dyskinesia, Drug-Induced; Humans; Levodopa; Microscopy, Confocal; Motor Activity; Motor Neurons; Parkinsonian Disorders; Pattern Recognition, Automated; Receptors, Dopamine

Alpha-synuclein (α-SYN) aggregates represent a key feature of Parkinson's disease, but the exact relationship between α-SYN aggregation and neurodegeneration remains incompletely understood. Therefore, the availability of a cellular assay that allows medium-throughput analysis of α-SYN-linked pathology will be of great value for studying the aggregation process and for advancing α-SYN-based therapies.. Here we describe a high-content neuronal cell assay that simultaneously measures oxidative stress-induced α-SYN aggregation and apoptosis.. We optimized an automated and reproducible assay to quantify both α-SYN aggregation and cell death in human SH-SY5Y neuroblastoma cells.. Quantification of α-SYN aggregates in cells has typically relied on manual imaging and counting or cell-free assays, which are time consuming and do not allow a concurrent analysis of cell viability. Our high-content analysis method for quantification of α-SYN aggregation allows simultaneous measurements of multiple cell parameters at a single-cell level in a fast, objective and automated manner.. The presented analysis approach offers a rapid, objective and multiparametric approach for the screening of compounds and genes that might alter α-SYN aggregation and/or toxicity.

Topics: alpha-Synuclein; Apoptosis; Benzothiazoles; Blotting, Western; Cell Count; Cell Culture Techniques; Cell Line, Tumor; Cell Survival; Genetic Vectors; Humans; Image Processing, Computer-Assisted; Immunohistochemistry; Indoles; Lentivirus; Microscopy, Fluorescence; Oxidative Stress; Parkinsonian Disorders; Protein Aggregation, Pathological; Protein Multimerization; Software; Thiazoles

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

Animal and cell experiments showed that inositol hexaphosphate (IP6) was protective on neurons in parkinson's disease (PD) model, but the underlying mechanism of this action was not extensively elucidated. To address this question, we established 6-hydroxydopamine (6-OHDA) induced human dopaminergic cell line SH-SY5Y as PD cell model and testified the neuroprotection of IP6. Through hoechst nuclear stain method and flow cytometric analysis, apoptosis induced by 6-OHDA was blocked by IP6 pretreatment. Significant protection against reactive oxygen species (ROS) and lipid peroxidation product malondialdehyde (MDA) was observed in 6-OHDA induced cells pretreated with IP6. To further investigate the mechanism of anti-apoptotic effect of IP6, expression of mediators in mitochondrion dependent apoptotic pathway was detected. Results indicated that loss of mitochondrial membrane potential, cytochrome c releasing, upregulation of Bcl-2-associated X protein (Bax), downregulation of B-cell CLL/lymphoma 2 (Bcl-2) and caspases activation were reversed by IP6. In addition, using flow cytometric method and western blot approach, our data showed that IP6 attenuated the rise of calcium and α-synuclein aggregation in cytosol. Collectively, IP6 exerted its neuroprotection on dopaminergic cells in PD cell model and the mechanism may be associated with changes of mitochondrion mediated apoptotic pathway and α-synuclein aggregation.

Topics: Adrenergic Agents; alpha-Synuclein; Apoptosis; Blotting, Western; Cell Line, Tumor; Flow Cytometry; Humans; Membrane Potential, Mitochondrial; Neurons; Neuroprotective Agents; Oxidopamine; Parkinsonian Disorders; Phytic Acid

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

Topics: alpha-Synuclein; Animals; Female; Humans; Male; Multiple System Atrophy; Parkinsonian Disorders; Prions

Midbrain dopaminergic neurons are essential for appropriate voluntary movement, as epitomized by the cardinal motor impairments arising in Parkinson's disease. Understanding the basis of such motor control requires understanding how the firing of different types of dopaminergic neuron relates to movement and how this activity is deciphered in target structures such as the striatum. By recording and labeling individual neurons in behaving mice, we show that the representation of brief spontaneous movements in the firing of identified midbrain dopaminergic neurons is cell-type selective. Most dopaminergic neurons in the substantia nigra pars compacta (SNc), but not in ventral tegmental area or substantia nigra pars lateralis, consistently represented the onset of spontaneous movements with a pause in their firing. Computational modeling revealed that the movement-related firing of these dopaminergic neurons can manifest as rapid and robust fluctuations in striatal dopamine concentration and receptor activity. The exact nature of the movement-related signaling in the striatum depended on the type of dopaminergic neuron providing inputs, the striatal region innervated, and the type of dopamine receptor expressed by striatal neurons. Importantly, in aged mice harboring a genetic burden relevant for human Parkinson's disease, the precise movement-related firing of SNc dopaminergic neurons and the resultant striatal dopamine signaling were lost. These data show that distinct dopaminergic cell types differentially encode spontaneous movement and elucidate how dysregulation of their firing in early Parkinsonism can impair their effector circuits.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Dopamine; Dopaminergic Neurons; Male; Mice, Inbred C57BL; Mice, Transgenic; Models, Biological; Movement; Parkinsonian Disorders; Substantia Nigra; Ventral Tegmental Area

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

Passive and active immunization with α-synuclein has been shown to be neuroprotective in animal models of Parkinson's disease. We have previously shown that vaccination with α-synuclein, long before α-synuclein-induced brain pathology, prevents striatal degeneration by inducing regulatory T cell infiltration in parenchyma and antibody deposition on α-synuclein overexpressing neurons. However, the effect of peripheral α-synuclein on the immune system is unknown, as are the mechanistic changes induced in the CD4 T cell population during successful neuroprotective animal studies. We have studied the changes induced by vaccination with α-synuclein in the CD4 T cell pool and its impact on brain microglia to understand the immune mechanisms behind successful vaccination strategies in Parkinson's disease animal models.. Mice were immunized with WT or nitrated α-synuclein at a dose equivalent to the one used in our previous successful vaccination strategy and at a higher dose to determine potential dose-dependent effects. Animals were re-vaccinated 4 weeks after and sacrificed 5 days later. These studies were conducted in naive animals in the absence of human α-synuclein expression.. The CD4 T cell response was modulated by α-synuclein in a dose-dependent manner, in particular the regulatory T cell population. Low-dose α-synuclein induced expansion of naive (Foxp3 + CCR6-CD127lo/neg) and dopamine receptor type D3+ regulatory T cells, as well as an increase in Stat5 protein levels. On the other hand, high dose promoted activation of regulatory T cells (Foxp3CCR6 + CD127lo/neg), which were dopamine receptor D2+D3-, and induced up-regulation of Stat5 and production of anti-α-synuclein antibodies. These effects were specific to the variant of α-synuclein used as the pathology-associated nitrated form induced distinct effects at both doses. The changes observed in the periphery after vaccination with low-dose α-synuclein correlated with an increase in CD154+, CD103+, and CD54+ microglia and the reduction of CD200R+ microglia. This resulted in the induction of a polarized tolerogenic microglia population that was CD200R-CD54CD103CD172a+ (82 % of total microglia).. We have shown for the first time the mechanisms behind α-synuclein vaccination and, importantly, how we can modulate microglia's phenotype by regulating the CD4 T cell pool, thus shedding invaluable light on the design of neuroimmunoregulatory therapies for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Blotting, Western; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Humans; Immunohistochemistry; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Microglia; Parkinsonian Disorders; Recombinant Proteins; T-Lymphocytes, Regulatory; Vaccination

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

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

In contrast to the complexity found in mammals, only two Bcl-2 family genes have been found in Drosophila melanogaster including the pro-cell survival, human Bok-related orthologue, Buffy. The directed expression of α-synuclein, the first gene identified to contribute to inherited forms of Parkinson disease (PD), in the dopaminergic neurons (DA) of flies has provided a robust and well-studied Drosophila model of PD complete with the loss of neurons and accompanying motor defects. To more fully understand the biological basis of Bcl-2 genes in PD, we altered the expression of Buffy in the dopamine producing neurons with and without the expression of α-synuclein, and in the developing neuron-rich eye.. To alter the expression of Buffy in the dopaminergic neurons of Drosophila, the Ddc-Gal4 transgene was used. The directed expression of Buffy in the dopamine producing neurons resulted in flies with increased climbing ability and enhanced survival, while the inhibition of Buffy in the dopaminergic neurons reduced climbing ability over time prematurely, similar to the phenotype observed in the α-synuclein-induced Drosophila model of PD. Subsequently, the expression of Buffy was altered in the α-synuclein-induced Drosophila model of PD. Analysis revealed that Buffy acted to rescue the associated loss of locomotor ability observed in the α-synuclein-induced model of PD, while Buffy RNA interference resulted in an enhanced α-synuclein-induced loss of climbing ability. In complementary experiments the overexpression of Buffy in the developing eye suppressed the mild rough eye phenotype that results from Gal4 expression and from α-synuclein expression. When Buffy is inhibited the roughened eye phenotype is enhanced.. The inhibition of Buffy in DA neurons produces a novel model of PD in Drosophila. The directed expression of Buffy in DA neurons provide protection and counteracts the α-synuclein-induced Parkinson disease-like phenotypes. Taken all together this demonstrates a role for Buffy, a Bcl-2 pro-cell survival gene, in neuroprotection.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cohort Studies; Conserved Sequence; Dopaminergic Neurons; Drosophila melanogaster; Drosophila Proteins; Eye; Humans; Locomotion; Male; Microscopy, Electron, Scanning; Neuroprotection; Parkinsonian Disorders; Phenotype; Proto-Oncogene Proteins c-bcl-2; Sequence Homology, Amino Acid

While increasing life expectancy is a major achievement, the global aging of societies raises a number of medical issues, such as the development of age-related disorders, including neurodegenerative diseases. The three main disease groups constituting the majority of neurodegenerative diseases are tauopathies, alpha-synucleinopathies and diseases due to repetitions of glutamine (including Huntington's disease). In each neurodegenerative disease, the accumulation of one or more aggregated proteins has been identified as the molecular signature of the disease (as seen, for example, in Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies, amyotrophic lateral sclerosis and frontotemporal dementia). The etiology of neurodegenerative diseases is often multifactorial, and the known risk factors include, in addition to genetic polymorphisms and age, some other possible causes, such as certain immune and metabolic conditions, endocrine pathologies, gender, socioeconomic or professional status, oxidative stress or inflammation, vitamin deficiencies and environmental factors (chemical exposure, metals). However, innovative strategies to elaborate suitable diagnostic and therapeutic approaches (aiming to at least delay or possibly even reverse disease progression) require further knowledge of the genetic and adaptive immunological characteristics of neurodegenerative diseases.

Topics: alpha-Synuclein; Brain; Cytoskeleton; Humans; Inclusion Bodies; Lewy Body Disease; Nerve Degeneration; Neurodegenerative Diseases; Parkinsonian Disorders; Tauopathies

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

Among the known genetic risk factors for Parkinson disease, mutations in GBA1, the gene responsible for the lysosomal disorder Gaucher disease, are the most common. This genetic link has directed attention to the role of the lysosome in the pathogenesis of parkinsonism. To study how glucocerebrosidase impacts parkinsonism and to evaluate new therapeutics, we generated induced human pluripotent stem cells from four patients with Type 1 (non-neuronopathic) Gaucher disease, two with and two without parkinsonism, and one patient with Type 2 (acute neuronopathic) Gaucher disease, and differentiated them into macrophages and dopaminergic neurons. These cells exhibited decreased glucocerebrosidase activity and stored the glycolipid substrates glucosylceramide and glucosylsphingosine, demonstrating their similarity to patients with Gaucher disease. Dopaminergic neurons from patients with Type 2 and Type 1 Gaucher disease with parkinsonism had reduced dopamine storage and dopamine transporter reuptake. Levels of α-synuclein, a protein present as aggregates in Parkinson disease and related synucleinopathies, were selectively elevated in neurons from the patients with parkinsonism or Type 2 Gaucher disease. The cells were then treated with NCGC607, a small-molecule noninhibitory chaperone of glucocerebrosidase identified by high-throughput screening and medicinal chemistry structure optimization. This compound successfully chaperoned the mutant enzyme, restored glucocerebrosidase activity and protein levels, and reduced glycolipid storage in both iPSC-derived macrophages and dopaminergic neurons, indicating its potential for treating neuronopathic Gaucher disease. In addition, NCGC607 reduced α-synuclein levels in dopaminergic neurons from the patients with parkinsonism, suggesting that noninhibitory small-molecule chaperones of glucocerebrosidase may prove useful for the treatment of Parkinson disease.. Because GBA1 mutations are the most common genetic risk factor for Parkinson disease, dopaminergic neurons were generated from iPSC lines derived from patients with Gaucher disease with and without parkinsonism. These cells exhibit deficient enzymatic activity, reduced lysosomal glucocerebrosidase levels, and storage of glucosylceramide and glucosylsphingosine. Lines generated from the patients with parkinsonism demonstrated elevated levels of α-synuclein. To reverse the observed phenotype, the neurons were treated with a novel noninhibitory glucocerebrosidase chaperone, which successfully restored glucocerebrosidase activity and protein levels and reduced glycolipid storage. In addition, the small-molecule chaperone reduced α-synuclein levels in dopaminergic neurons, indicating that chaperoning glucocerebrosidase to the lysosome may provide a novel therapeutic strategy for both Parkinson disease and neuronopathic forms of Gaucher disease.

Topics: Acetanilides; alpha-Synuclein; Benzamides; beta-Glucosidase; Catecholamines; Cell Differentiation; Dopaminergic Neurons; Female; Gaucher Disease; Glucosylceramidase; Glucosylceramides; Glycolipids; Humans; Induced Pluripotent Stem Cells; Inhibitory Postsynaptic Potentials; Lysosomal-Associated Membrane Protein 2; Macrophages; Male; Membrane Potentials; Mutation; Parkinsonian Disorders; Patch-Clamp Techniques

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

α-Synuclein (αSyn) is a major constituent of proteinaceous aggregates in neurodegenerative diseases such as Parkinson's disease (PD) and a potential biomarker candidate for diagnosis and treatment effects. However, studies about αSyn in cerebrospinal fluid (CSF) in diseases are inconsistent and mainly based on immunological assays. Quantitative information about β-synuclein (βSyn) and γ-synuclein (γSyn) in CSF is not available.Here, we present an alternative method for the simultaneous quantification of αSyn, βSyn and γSyn in CSF by multiple reaction monitoring (MRM) with a high sequence coverage (70%) of αSyn to validate previous, ELISA-based results and characterize synucleins in CSF in more detail.The MRM has high sensitivity in the low pg/ml range (3-30pg/ml full-length αSyn) using 200 μl CSF. A high portion of CSF αSyn is present in the N-terminally acetylated form and the concentration of unmodified peptides in the nonamyloid component region is about 40% lower than in the N-terminal region. Synuclein concentrations show a high correlation with each other in CSF (r>0.80) and in contrast to αSyn and γSyn, βSyn is not affected by blood contamination. CSF αSyn, βSyn and γSyn concentrations were increased in Alzheimer's and Creutzfeldt-Jakob disease but not altered in PD, PD dementia (PDD), Lewy body dementia and atypical parkinsonian syndromes. The ratio βSyn/αSyn was increased in PDD (1.49 ± 0.38, p < 0.05) compared with PD (1.11 ± 0.26) and controls (1.15 ± 0.28). βSyn shows a high correlation with CSF tau concentrations (r = 0.86, p < 0.0001, n = 125).In conclusion, we could not confirm previous observations of reduced αSyn in PD and our results indicate that CSF synuclein concentrations are rather general markers of synaptic degeneration than specific for synucleinopathies. βsyn is an attractive biomarker candidate that might be used as an alternative to or in combination with tau in AD and CJD diagnosis and in combination with αSyn it is a biomarker candidate for PDD.

Topics: alpha-Synuclein; Alzheimer Disease; beta-Synuclein; Biomarkers; Creutzfeldt-Jakob Syndrome; Diagnostic Tests, Routine; gamma-Synuclein; Humans; Mass Spectrometry; Parkinsonian Disorders; Sensitivity and Specificity

Parkinson's disease is one of the most common neurodegenerative disorders of the elderly and ageing hence described to be a major risk factor. Telomere shortening as a result of the inability to fully replicate the ends of linear chromosomes is one of the hallmarks of ageing. The role of telomere dysfunction in neurological diseases and the ageing brain is not clarified and there is an ongoing discussion whether telomere shortening is linked to Parkinson's disease. Here we studied a mouse model of Parkinson's disease (Thy-1 [A30P] α-synuclein transgenic mouse model) in the background of telomere shortening (Terc knockout mouse model). α-synuclein transgenic mice with short telomeres (αSYN(tg/tg) G3Terc(-/-)) developed an accelerated disease with significantly decreased survival. This accelerated phenotype of mice with short telomeres was characterized by a declined motor performance and an increased formation of α-synuclein aggregates. Immunohistochemical analysis and mRNA expression studies revealed that the disease end-stage brain stem microglia showed an impaired response in αSYN(tg/tg) G3Terc(-/-) microglia animals. These results provide the first experimental data that telomere shortening accelerates α-synuclein pathology that is linked to limited microglia function in the brainstem.

Topics: alpha-Synuclein; Animals; Brain Stem; Disease Progression; Humans; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Motor Activity; Parkinsonian Disorders; Phenotype; Postural Balance; Protein Aggregation, Pathological; RNA, Messenger; Telomere Shortening; Time Factors

Amyloid beta (Aβ) aggregation is generally associated with Alzheimer's onset. Here, we demonstrate that incubation of dopaminergic SH-SY5Y cells with an Aβ peptide fragment (an 11-mer composed of residues 25-35; Aβ (25-35)) results in elevated intracellular nitrosative stress and induces chemical mutation of protein disulfide isomerase (PDI), an endoplasmic reticulum-resident oxidoreductase chaperone. Furthermore, Aβ (25-35) provokes aggregation of both the minor and major biomarkers of Parkinson's disease, namely, synphilin-1 and α-synuclein, respectively. Importantly, fluorescence studies demonstrate that Aβ (25-35) triggers colocalization of these Parkinsonian biomarkers to form Lewy-body-like aggregates, a key and irreversible milestone in the neurometabolic cascade leading to Parkinson's disease. In addition, fluorescence assays also reveal direct, aggregation-seeding interactions between Aβ (25-35), PDI and α-synuclein, suggesting neuronal pathogenesis occurs via prion-type cross-transfectivity. These data indicate that the introduction of an Alzheimer's-associated biomarker in dopaminergic cells is proliferative, with the percolative effect exercised via dual, independent, Parkinson-pathogenic pathways, one stress-derived and the other prion-like. The results define a novel molecular roadmap for Parkinsonian transfectivity via an Alzheimeric burden and reveal the involvement of PDI in amyloid beta induced Parkinson's.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Apoptosis; Biomarkers; Carrier Proteins; Cell Line, Tumor; Cytosol; Dopaminergic Neurons; Dynamic Light Scattering; Flow Cytometry; Green Fluorescent Proteins; Immunohistochemistry; Immunoprecipitation; Intracellular Signaling Peptides and Proteins; Lewy Bodies; Mice; Microscopy, Confocal; Nerve Tissue Proteins; Parkinsonian Disorders; Peptide Fragments; Protein Aggregation, Pathological; Reactive Oxygen Species; Transfection

Parkinson's disease (PD) is the most widespread form of dementia where there is an age related degeneration of dopaminergic neurons in the substantia nigra region of the brain. Accumulation of α-synuclein (αS) protein aggregate, mitochondrial dysfunction, oxidative stress, and neuronal cell death are the pathological hallmarks of PD. In this context, amalgamation of curcumin and piperine having profound cognitive properties, and antioxidant activity seems beneficial. However, the blood-brain barrier (BBB) is the major impediment for delivery of neurotherapeutics to the brain. The present study involves formulation of curcumin and piperine coloaded glyceryl monooleate (GMO) nanoparticles coated with various surfactants with a view to enhance the bioavailability of curcumin and penetration of both drugs to the brain tissue crossing the BBB and to enhance the anti-parkinsonism effect of both drugs in a single platform. In vitro results demonstrated augmented inhibition of αS protein into oligomers and fibrils, reduced rotenone induced toxicity, oxidative stress, and apoptosis, and activation of autophagic pathway by dual drug loaded NPs compared to native counterpart. Further, in vivo studies revealed that our formulated dual drug loaded NPs were able to cross BBB, rescued the rotenone induced motor coordination impairment, and restrained dopaminergic neuronal degeneration in a PD mouse model.

Topics: Alkaloids; alpha-Synuclein; Animals; Antiparkinson Agents; Benzodioxoles; Blood-Brain Barrier; Capillary Permeability; Curcumin; Drug Delivery Systems; Drug Therapy, Combination; Liposomes; Male; Mice, Inbred BALB C; Mice, Inbred C57BL; Nanoparticles; Neuroprotective Agents; Parkinsonian Disorders; PC12 Cells; Piperidines; Polyunsaturated Alkamides; Protein Aggregation, Pathological; Random Allocation; Rats; Rotenone; Surface-Active Agents

The pathological features of Parkinson's disease (PD) include an abnormal accumulation of α-synuclein in the surviving dopaminergic neurons. Though PD is multifactorial, several epidemiological reports show an increased incidence of PD with co-exposure to pesticides such as Maneb and paraquat (MP). In pesticide-related PD, mitochondrial dysfunction and α-synuclein oligomers have been strongly implicated, but the link between the two has not yet been understood. Similarly, the biological effects of α-synuclein or its radical chemistry in PD is largely unknown. Mitochondrial dysfunction during PD pathogenesis leads to release of cytochrome c in the cytosol. Once in the cytosol, cytochrome c has one of two fates: It either binds to apaf1 and initiates apoptosis or can act as a peroxidase. We hypothesized that as a peroxidase, cytochrome c leaked out from mitochondria can form radicals on α-synuclein and initiate its oligomerization.. Samples from controls, and MP co-exposed wild-type and α-synuclein knockout mice were studied using immuno-spin trapping, confocal microscopy, immunohistochemistry, and microarray experiments.. Experiments with MP co-exposed mice showed cytochrome c release in cytosol and its co-localization with α-synuclein. Subsequently, we used immuno-spin trapping method to detect the formation of α-synuclein radical in samples from an in vitro reaction mixture consisting of cytochrome c, α-synuclein, and hydrogen peroxide. These experiments indicated that cytochrome c plays a role in α-synuclein radical formation and oligomerization. Experiments with MP co-exposed α-synuclein knockout mice, in which cytochrome c-α synuclein co-localization and interaction cannot occur, mice showed diminished protein radical formation and neuronal death, compared to wild-type MP co-exposed mice. Microarray data from MP co-exposed wild-type and α-synuclein knockout mice further showed that the absence of α-synuclein per se or its co-localization with cytochrome c confers protection from MP co-exposure, as several important pathways were unaffected in α-synuclein knockout mice.. Altogether, these results show that peroxidase activity of cytochrome c contributes to α-synuclein radical formation and oligomerization, and that α-synuclein, through its co-localization with cytochrome c or on its own, affects several biological pathways which contribute to increased neuronal death in an MP-induced model of PD.

Topics: alpha-Synuclein; Animals; Cell Death; Cytochromes c; Free Radicals; Immunohistochemistry; Male; Maneb; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Confocal; Neurons; Oligonucleotide Array Sequence Analysis; Oxidative Stress; Paraquat; Parkinsonian Disorders; Pesticides

In Parkinson's disease, α-synuclein is known to activate microglia and this activation has been proposed as one of the mechanisms of neurodegeneration. There are several signals produced by neurons that have an anti-inflammatory action on microglia, including CX3CL1 (fractalkine). We have shown that a soluble form of CX3CL1 is required to reduce neuron loss in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice and that fractalkine agonism can reduce neuron loss in a 6-hydroxydopamine lesion model. Here, we show that fractalkine can reduce α-synuclein-mediated neurodegeneration in rats. Rats that received fractalkine showed abrogated loss of tyrosine hydroxylase and Neu-N staining. This was replicated in animals where we expressed fractalkine from astrocytes with the glial fibrillary acid protein (GFAP) promoter. Interestingly, we did not observe a reduction in MHCII expression suggesting that soluble fractalkine is likely altering the microglial state to a more neuroprotective one rather than reducing antigen presentation.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Antigen Presentation; Astrocytes; Chemokine CX3CL1; Dependovirus; Gene Expression Regulation; Genetic Therapy; Genetic Vectors; Glial Fibrillary Acidic Protein; Histocompatibility Antigens Class II; Male; Mice; Microglia; Nerve Tissue Proteins; Neurons; Oxidopamine; Parkinson Disease, Secondary; Parkinsonian Disorders; Promoter Regions, Genetic; Rats; Signal Transduction; Substantia Nigra; Tyrosine 3-Monooxygenase

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

Several clinical studies point to a high prevalence of psychotic symptoms in frontotemporal dementia associated with C9ORF72 mutations, but clinicopathological studies addressing the association between C9ORF72 mutations and delusions are lacking.. Seventeen patients with pathologically proven frontotemporal lobar degeneration (FTLD) associated with C9ORF72 mutations were identified from Neurodegenerative Disease Brain Bank. Of the 17 cases with C9ORF72 mutation, 4 exhibited well-defined delusions. The clinical history, neurological examination, neuropsychological testing, neuroimaging analysis, and postmortem assessment of the patients with delusions were evaluated and compared with the other cases.. The content of the delusions was mixed including persecution, infidelity, and grandiosity. All cases showed parkinsonism; voxel-based morphometry analysis showed greater precuneus atrophy in patients with delusions than those without delusions. All 4 had unclassifiable FTLD with TAR DNA-binding protein inclusions, with characteristics of both type A and type B. Three cases had additional τ pathology and another had α-synuclein pathology.. C9ORF72 carriers with well-defined delusions likely associated with additional pathologies and parietal atrophy in neuroimaging. Patients presenting with middle-aged onset of delusions should be screened for C9ORF72 mutations, especially if family history and parkinsonism are present.

Topics: Adult; Aged; alpha-Synuclein; Atrophy; Autopsy; Delusions; DNA-Binding Proteins; Frontotemporal Dementia; Frontotemporal Lobar Degeneration; Heterozygote; Humans; Male; Middle Aged; Mutation; Neuroimaging; Neurologic Examination; Neuropsychological Tests; Open Reading Frames; Parietal Lobe; Parkinsonian Disorders; tau Proteins

Lewy bodies (ubiquitin and α-synuclein aggregates) can be detected in brain areas in a predictable sequence of six neuropathological stages in Parkinson's disease. Brainstem and olfactory structures are involved in stage 1, whereas the substantia nigra and amygdala are involved in stage 3, prior to cortical spreading. Amygdaloid pathology has been suggested to contribute to non-motor symptoms such as olfactory dysfunction and emotional impairment. This work analysed the distribution of α-synuclein at 16, 30, 43 and 56 weeks in the basolateral, central and cortical amygdaloid complexes of A53T transgenic mice. The expression of calbindin, calretinin and somatostatin was compared in control and transgenic animals. Co-localisation of these markers with α-synuclein was performed. Triple labeling of calbindin, somatostatin and α-synuclein was also investigated. Quantification was carried out using an optical dissector, ImageJ software and confocal microscopy. α-Synuclein-positive cells were mainly concentrated in the basolateral and cortical amygdaloid complexes with a non-significant increase over time from 16 to 30-43 weeks and a significant decrease thereafter. The expression of interneuron markers showed a significant decrease with aging in control animals. When comparing these markers between control and transgenic mice, calretinin was moderately decreased, but calbindin and somatostatin were highly reduced, particularly in the cortical amygdaloid complex. α-Synuclein mostly co-localised with calbindin and a number of these cells also co-expressed somatostatin. These data on α-synucleinopathy staging in the amygdala could help to explain non-motor symptoms as well as to understand the progression of Parkinson's disease in the brain.

Topics: Aging; alpha-Synuclein; Amygdala; Animals; Calbindin 2; Calbindins; Disease Progression; Female; Immunohistochemistry; Interneurons; Male; Mice, Transgenic; Microscopy, Confocal; Parkinsonian Disorders; Severity of Illness Index; Somatostatin

Cypermethrin induces the mitochondrial dysfunction and oxidative damage to the nigrostriatal dopaminergic neurons leading to Parkinsonism in rats. Despite α-synuclein aggregation is reported to be critical in Parkinson's disease, its role and alliance with the mitochondrial dysfunction and oxidative damage leading to cypermethrin-induced Parkinsonism have not yet been deciphered. The present study aimed to examine the effect of cypermethrin on the expression and aggregation of α-synuclein and its subsequent connection with oxidative damage and mitochondrial dysfunction leading to the nigrostriatal dopaminergic neurodegeneration in the presence or absence of a mitochondrial membrane transition pore opening inhibitor, cyclosporine A and a superoxide dismutase/catalase mimetic, manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP). The expression of α-synuclein, 3-nitrotyrosine (3-NT), 4-hydroxynonenal (4-HNE)-modified proteins, mitochondrial dysfunction-dependent apoptotic proteins, nitrite content, lipid peroxidation (LPO) and number of tyrosine hydroxylase (TH)-positive neurons were estimated in the substantia nigra and dopamine content in the striatum of control and treated rats employing standard procedures. Cypermethrin augmented the expression of α-synuclein, 3-NT, 4-HNE-modified proteins, caspase-3, mitochondrial Bax and cytosolic cytochrome-c along with nitrite and LPO and reduced the expression of cytosolic Bax, mitochondrial cytochrome-c, dopamine and number of TH-positive neurons. Cyclosporine A or MnTMPyP alleviated the expression and aggregation of α-synuclein along with indicators of the mitochondrial dysfunction, oxidative damage and dopaminergic neurodegeneration. The results demonstrate that cypermethrin induces α-synuclein expression and aggregation while cyclosporine A or MnTMPyP rescues from α-synuclein over-expression and aggregation along with the mitochondrial dysfunction and oxidative damage leading to Parkinsonism in rats.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Cyclosporine; Dopaminergic Neurons; Metalloporphyrins; Mitochondria; Oxidative Stress; Parkinson Disease; Parkinsonian Disorders; Pyrethrins; Rats, Wistar; Substantia Nigra

Aberrant posttranslational modifications (PTMs) of proteins, namely phosphorylation, induce abnormalities in the biological properties of recipient proteins, underlying neurological diseases including Parkinson's disease (PD). Genome-wide studies link genes encoding α-synuclein (α-Syn) and Tau as two of the most important in the genesis of PD. Although several kinases are known to phosphorylate α-Syn and Tau, we focused our analysis on GSK-3β because of its accepted role in phosphorylating Tau and to increasing evidence supporting a strong biophysical relationship between α-Syn and Tau in PD. Therefore, we investigated transgenic mice, which express a point mutant (S9A) of human GSK-3β. GSK-3β-S9A is capable of activation through endogenous natural signaling events, yet is unable to become inactivated through phosphorylation at serine-9. We used behavioral, biochemical, and in vitro analysis to assess the contributions of GSK-3β to both α-Syn and Tau phosphorylation. Behavioral studies revealed progressive age-dependent impairment of motor function, accompanied by loss of tyrosine hydroxylase-positive (TH+ DA-neurons) neurons and dopamine production in the oldest age group. Magnetic resonance imaging revealed deterioration of the substantia nigra in aged mice, a characteristic feature of PD patients. At the molecular level, kinase-active p-GSK-3β-Y216 was seen at all ages throughout the brain, yet elevated levels of p-α-Syn-S129 and p-Tau (S396/404) were found to increase with age exclusively in TH+ DA-neurons of the midbrain. p-GSK-3β-Y216 colocalized with p-Tau and p-α-Syn-S129. In vitro kinase assays showed that recombinant human GSK-3β directly phosphorylated α-Syn at a single site, Ser129, in addition to its known ability to phosphorylate Tau. Moreover, α-Syn and Tau together cooperated with one another to increase the magnitude or rate of phosphorylation of the other by GSK-3β. Together, these data establish a novel upstream role for GSK-3β as one of several kinases associated with PTMs of key proteins known to be causal in PD.

Topics: alpha-Synuclein; Animals; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Mice; Mice, Transgenic; Parkinsonian Disorders; tau Proteins

Rotenone is an environmental neurotoxin that induces accumulation of α-synuclein and degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc), but the molecular mechanisms are not fully understood. We investigated whether rotenone induced impairment of autophagic flux and lysosomal functions.. Autophagy flux, accumulation of α-synuclein, lysosomal membrane integrity and neurodegeneration were assessed in the rotenone-treated rat model and PC12 cells, and the effects of the autophagy inducer trehalose on rotenone's cytotoxicity were also studied.. Rotenone administration significantly reduced motor activity and caused a loss of tyrosine hydroxylase in SNpc of Lewis rats. The degeneration of nigral dopaminergic neurons was accompanied by the deposition of α-synuclein aggregates, autophagosomes and redistribution of cathepsin D from lysosomes to the cytosol. In cultured PC12 cells, rotenone also induced increases in protein levels of α-synuclein, microtubule-associated protein 1 light chain 3-II, Beclin 1, and p62. Rotenone increased lysosomal membrane permeability as evidenced by leakage of N-acetyl-beta-d-glucosaminidase and cathepsin D, the effects were blocked by reactive oxygen species scavenger tiron. Autophagy inducer trehalose enhanced the nuclear translocation of transcription factor EB, accelerated the clearance of autophagosomes and α-synuclein and attenuated rotenone-induced cell death of PC12 cells. Meanwhile, administration of trehalose to rats in drinking water (2%) decreased rotenone-induced dopaminergic neurons loss in SNpc.. These studies indicate that the lysosomal dysfunction contributes to rotenone's neurotoxicity and restoration of lysosomal function could be a new therapeutic strategy for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Autophagy; Lysosomes; Male; Parkinsonian Disorders; Pars Compacta; PC12 Cells; Random Allocation; Rats; Rats, Inbred Lew; Rotenone; Trehalose; Tyrosine 3-Monooxygenase

Alpha-synuclein (α-syn) toxic aggregates delivered by the nasal vector have been shown to modify the neurochemistry of dopamine (DA) which is associated with parkinsonian-like motor symptoms. The aim was therefore to study the intranasal effects of α-syn oligomers, fibrils or their combination on the motor behavior of aged mice in relation to possible noradrenergic and serotonergic correlates. In vitro generated α-syn oligomers and fibrils were verified using atomic force microscopy and the thioflavin T binding assay. Levels of noradrenaline (NA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were detected using HPLC with electrochemical detection in the substantia nigra (SN) and striatum. The oligomers or fibrils administered alone or in a 50:50 combination (total dose of 0.48 mg/kg) were given intranasally for 14 days and "open-field" behaviour was tested on days 0, 15 and 28 of the protocol, at which time brain structures were sampled. Behavioral deficits at the end of the 14-day dosing regime and on day 28 (i.e. 14 days after treatment completion) induced hypokinesia and immobility whilst the aggregate combination additionally produced rigidity. The α-Syn oligomer/fibril mixture also instigated PD-like motor symptoms which correlated heterochronically with elevated NA levels in the striatum but then later in the SN while intranasal fibrils alone augmented 5-HT and 5-HIAA nigral concentrations throughout the protocol. In contrast, α-syn oligomers displayed a delayed serotonin upsurge in the SN. Neurodegenerative and/or actions on neurotransmitter transporters (such as NET, SERT and VMAT2) are discussed as being implicated in these α-syn amyloid induced neurochemical and motoric disturbances.

Topics: Administration, Intranasal; alpha-Synuclein; Amyloid; Animals; Hydroxyindoleacetic Acid; Male; Mice; Mice, Inbred C57BL; Motor Activity; Neostriatum; Norepinephrine; Parkinsonian Disorders; Protein Aggregates; Serotonin; Substantia Nigra

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

Tea polyphenols (TPs) are bioactive flavanol-related catechins that have been shown to protect dopaminergic (DAergic) neurons against neurotoxin-induced injury in mouse Parkinson's disease (PD) models. However, the neuroprotective efficacy of TP has not been investigated in nonhuman PD primates, which can more accurately model the neuropathology and motor impairments of human PD patients. Here, we show that oral administration of TP alleviates motor impairments and DAergic neuronal injury in the substantia nigra in N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated PD monkeys, indicating an association between protection against motor deficits and preservation of DAergic neurons. We also show a significant inhibition of MPTP-induced accumulation of neurotoxic α-synuclein (α-syn) oligomers in the striatum and other brain regions, which may contribute to the neuroprotection and improved motor function conferred by TP. The association between reduced α-syn oligomerization and neuroprotection was confirmed in cultured DAergic cells. The most abundant and bioactive TP in the mixture used in vivo, (-)-epigallocatechin-3-gallate, reduced intracellular levels of α-syn oligomers in neurons treated with α-syn oligomers, 1-methyl-4-phenylpyridiniumion, or both, accompanied by increased cell viability. The present study provides the first evidence that TP can alleviate motor impairments, DAergic neuronal injury, and α-syn aggregation in nonhuman primates.

Topics: alpha-Synuclein; Animals; Catechin; Cell Survival; Corpus Striatum; Dopamine; Dopaminergic Neurons; Female; Macaca fascicularis; Motor Activity; Neuroprotective Agents; Parkinsonian Disorders; Substantia Nigra

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

14-3-3 proteins are key regulators of cell survival. We have previously demonstrated that 14-3-3 levels are decreased in an alpha-synuclein (αsyn) mouse model of Parkinson's disease (PD), and that overexpression of certain 14-3-3 isoforms is protective in several PD models. Here we examine whether changes in 14-3-3 phosphorylation may contribute to the neurodegenerative process in PD. We examine three key 14-3-3 phosphorylation sites that normally regulate 14-3-3 function, including serine 58 (S58), serine 184 (S184), and serine/threonine 232 (S/T232), in several models of PD and in human PD brain. We observed that an increase in S232 phosphorylation is observed in rotenone-treated neuroblastoma cells, in cells overexpressing αsyn, and in human PD brains. Alterations in S58 phosphorylation were less consistent in these models, and we did not observe any phosphorylation changes at S184. Phosphorylation at S232 induced by rotenone is reduced by casein kinase inhibitors, and is not dependent on αsyn. Mutation of the S232 site affected 14-3-3θ's neuroprotective effects against rotenone and 1-methyl-4-phenylpyridinium (MPP(+)), with the S232D mutant lacking any protective effect compared to wildtype or S232A 14-3-3θ. The S232D mutant partially reduced the ability of 14-3-3θ to inhibit Bax activation in response to rotenone. Based on these findings, we propose that phosphorylation of 14-3-3s at serine 232 contributes to the neurodegenerative process in PD.

Topics: 1-Methyl-4-phenylpyridinium; 14-3-3 Proteins; alpha-Synuclein; Animals; bcl-2-Associated X Protein; Casein Kinases; Cell Line, Tumor; Green Fluorescent Proteins; HEK293 Cells; Hippocampus; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice, Inbred C57BL; Mice, Transgenic; Parkinson Disease; Parkinsonian Disorders; Phosphorylation; Protein Serine-Threonine Kinases; Rotenone; Temporal Lobe

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

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

Epidemiological studies report a beneficial relationship between drinking coffee and the risk of developing Parkinson's disease (PD). This is likely due to caffeine, a constituent of coffee, acting as an adenosine A2A receptor antagonist. This study was planned to investigate whether caffeine has any effect on the aggregation of α-synuclein, present in Lewy bodies, the pathological hallmark of PD, which may account for this positive association. Aggregation of recombinant α-synuclein was followed in vitro and in a well-validated yeast proteotoxicity model of PD. Caffeine was found to have twin effects: it accelerated the process of aggregation and also altered the nature of mature aggregates. Aggregates formed in the presence of caffeine displayed amorphous as well as fibrillar morphology. In the presence of caffeine, the toxicity of oligomers and aggregates was diminished, with concomitant reduction in intracellular oxidative stress, decreased oxidative proteome damage, and increased cell survival. Caffeine-treated samples showed improved binding to phospholipids, a property likely to be important in cellular functioning of α-synuclein. Far-UV CD spectroscopy and fluorescence quenching analysis revealed that caffeine induced transient changes in this intrinsically disordered protein, forming a non-native species that enhanced the rate of aggregation of α-synuclein and modified the population of mature aggregates, introducing a higher fraction of amorphous, less toxic species. Increasingly, it is felt that the process of fibrillation itself, along with the nature of mature aggregates, dictates the cytotoxicity of the process. Our results provide a rationale for the observed epidemiological link between drinking coffee and developing PD.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Caffeine; Cell Survival; Drug Evaluation, Preclinical; Erythrocytes; Humans; Oxidation-Reduction; Oxidative Stress; Parkinsonian Disorders; Protein Aggregates; Rats; Reactive Oxygen Species; Recombinant Proteins; Saccharomyces cerevisiae

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

Vacuolar protein sorting-35 (VPS35) is essential for endosome-to-Golgi retrieval of membrane proteins. Mutations in the VPS35 gene have been identified in patients with autosomal dominant PD. However, it remains poorly understood if and how VPS35 deficiency or mutation contributes to PD pathogenesis. Here we provide evidence that links VPS35 deficiency to PD-like neuropathology. VPS35 was expressed in mouse dopamine (DA) neurons in substantia nigra pars compacta (SNpc) and STR (striatum)--regions that are PD vulnerable. VPS35-deficient mice exhibited PD-relevant deficits including accumulation of α-synuclein in SNpc-DA neurons, loss of DA transmitter and DA neurons in SNpc and STR, and impairment of locomotor behavior. Further mechanical studies showed that VPS35-deficient DA neurons or DA neurons expressing PD-linked VPS35 mutant (D620N) had impaired endosome-to-Golgi retrieval of lysosome-associated membrane glycoprotein 2a (Lamp2a) and accelerated Lamp2a degradation. Expression of Lamp2a in VPS35-deficient DA neurons reduced α-synuclein, supporting the view for Lamp2a as a receptor of chaperone-mediated autophagy to be critical for α-synuclein degradation. These results suggest that VPS35 deficiency or mutation promotes PD pathogenesis and reveals a crucial pathway, VPS35-Lamp2a-α-synuclein, to prevent PD pathogenesis. Significance statement: VPS35 is a key component of the retromer complex that is essential for endosome-to-Golgi retrieval of membrane proteins. Mutations in the VPS35 gene have been identified in patients with PD. However, if and how VPS35 deficiency or mutation contributes to PD pathogenesis remains unclear. We demonstrated that VPS35 deficiency or mutation (D620N) in mice leads to α-synuclein accumulation and aggregation in the substantia nigra, accompanied with DA neurodegeneration. VPS35-deficient DA neurons exhibit impaired endosome-to-Golgi retrieval of Lamp2a, which may contribute to the reduced α-synuclein degradation through chaperone-mediated autophagy. These results suggest that VPS35 deficiency or mutation promotes PD pathogenesis, and reveals a crucial pathway, VPS35-Lamp2a-α-synuclein, to prevent PD pathogenesis.

Topics: alpha-Synuclein; Animals; Autophagy; Blotting, Western; Cells, Cultured; Dopaminergic Neurons; Endosomes; Golgi Apparatus; Lysosomal-Associated Membrane Protein 2; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Microscopy, Confocal; Mutagenesis, Site-Directed; Parkinsonian Disorders; Protein Transport; Real-Time Polymerase Chain Reaction; Transfection; Vesicular Transport Proteins

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is pathologically characterized by loss of dopaminergic neurons from the substantia nigra, the presence of aggregated α-synuclein (αS) and evidence of neuroinflammation. Experimental studies have shown that the cerebral injection of recombinant fibrillar αS, especially in αS transgenic mouse models, can induce the formation and spread of αS inclusion pathology. However, studies reporting this phenomenon did not consider the presence of lipopolysaccharide (LPS) in the injected αS, produced in E. coli, as a potential confound. The objectives of this study are to develop a method to remove the LPS contamination and investigate the differences in pathologies induced by αS containing LPS or αS highly purified of LPS.. We were able to remove >99.5% of the LPS contamination from the αS preparations through the addition of a cation exchange step during purification. The αS pathology induced by injection of fibrils produced from αS containing LPS or purified of LPS, showed a similar distribution pattern; however, there was less spread into the cortex of the mice injected with αS containing higher levels of LPS. As previously reported, injection of αS fibrils could induce astrogliosis, and αS inclusions were present within astrocytes in mice injected with fibrils comprised of αS with or without cation exchange purification. Furthermore, we identified the presence of αS pathology in ependymal cells in both groups of mice, which suggests the involvement of a novel mechanism for spread in this model of αS pathology.

Topics: alpha-Synuclein; Animals; Astrocytes; Cell Count; Cells, Cultured; Chromatography, Ion Exchange; Disease Progression; Drug Contamination; Endotoxins; Entorhinal Cortex; Escherichia coli; Hippocampus; Humans; Hydrophobic and Hydrophilic Interactions; Inclusion Bodies; Inflammation; Injections; Mice; Mice, Transgenic; Microglia; Parkinsonian Disorders; Plaque, Amyloid; Protein Conformation; Recombinant Proteins

Epidemiological studies suggest an association between pesticides and the incidence of Parkinson's disease (PD). Individuals are likely to be exposed to numerous natural or synthetic environmental agents by ingestion, inhalation, or skin contact. Here, we describe a novel environment-contact administration of rotenone model, in which male C57BL/6 mice (15 per group per time-point) were placed in one bedding-free, rotenone-applied cage for 2h every day over a period of 2-6 weeks, mimicking the common ways a person may be exposed to pesticides. Our results showed that rotenone exposure had no detrimental effect on body weights of mice during 6 weeks, nor did it cause systemic toxicity (HPLC analysis of rotenone in blood and brain, as well as complex I activity measurements in brain and muscle), but it caused significant impairments in motor function (open field test, pole test, and rotarod test) from 4 weeks that were responsive to apomorphine. Accordingly, rotenone caused significant dopamine depletion from the striatum (HPLC analysis), nigrostriatal degeneration (quantitative tyrosine hydroxylase immunohistochemistry and western blot), and accumulation of α-synuclein in the substantia nigra and striatum (α-synuclein immunohistochemistry) in a time-dependent manner. In addition, rotenone-exposed mice also developed deficits in gastrointestinal and olfactory function (fecal pellet output and buried food pellet test) prior to the motor dysfunction. Furthermore, we observed that α-synuclein accumulated in the anterior olfactory nucleus and the enteric nervous system at 2 weeks. In summary, this novel rotenone model was able to reproduce many key aspects of PD progression. Therefore, it provides new insight into how environmental factors could trigger PD and provides a useful tool for studying PD pathogenesis and testing neuroprotective strategies.

Topics: alpha-Synuclein; Animals; Apomorphine; Body Weight; Brain; Disease Progression; Dopamine; Dopamine Agonists; Enteric Nervous System; Environmental Exposure; Housing, Animal; Male; Mice, Inbred C57BL; Motor Activity; Muscle, Skeletal; Neurons; Olfactory Perception; Parkinsonian Disorders; Rotenone; Tyrosine 3-Monooxygenase

The aggregation of α-synuclein (Syn or S) to form insoluble fibrils is important in the pathogenesis of Parkinson's disease, but key risk factors remain ill-defined. We have developed Fluorescence Resonance Energy Transfer (FRET)-based assays for α-synuclein aggregation, using Green Fluorescent Protein variants Cerulean (C) or Venus (V), fused to each other (CV, VC) or to human synuclein (SC, SV etc). Bacterially expressed proteins were purified to homogeneity, and C-terminal fusions SC and SV largely retained their ability to aggregate in vitro. FRET signals from mixtures of SC and SV were used to monitor aggregation. These fusion genes were linked to the C. elegans unc-54 myosin promoter to generate integrated transgenic strains. Increased FRET signals, indicative of S aggregation, were observed following treatment of unc-54::SC + unc-54::SV double transgenic worms with low concentrations of mercury or chlorpyrifos, or with RNAi against hsp-70 and hip-1. Opposite changes in Yellow Fluorescent Protein (YFP) fluorescence in an unc-54::SV strain (NL5901) are likely to reflect FRET from Yellow Fluorescent Protein to aggregates of Syn fusion protein. This could provide the basis for a high throughput screening assay, which could be used for studying the effects of toxic chemicals and environmental pollutants on the aggregation of proteins such as Syn in vivo.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Bacterial Proteins; Blotting, Western; Caenorhabditis elegans; Circular Dichroism; Escherichia coli; Fluorescence Resonance Energy Transfer; Green Fluorescent Proteins; HSP70 Heat-Shock Proteins; Humans; Luminescent Proteins; Microscopy, Confocal; Microscopy, Electron, Transmission; Parkinsonian Disorders; Protein Aggregates; Protein Aggregation, Pathological; RNA Interference

Extracellular α-synuclein (α-syn) assemblies can be up-taken by neurons; however, their interaction with the plasma membrane and proteins has not been studied specifically. Here we demonstrate that α-syn assemblies form clusters within the plasma membrane of neurons. Using a proteomic-based approach, we identify the α3-subunit of Na+/K+-ATPase (NKA) as a cell surface partner of α-syn assemblies. The interaction strength depended on the state of α-syn, fibrils being the strongest, oligomers weak, and monomers none. Mutations within the neuron-specific α3-subunit are linked to rapid-onset dystonia Parkinsonism (RDP) and alternating hemiplegia of childhood (AHC). We show that freely diffusing α3-NKA are trapped within α-syn clusters resulting in α3-NKA redistribution and formation of larger nanoclusters. This creates regions within the plasma membrane with reduced local densities of α3-NKA, thereby decreasing the efficiency of Na+ extrusion following stimulus. Thus, interactions of α3-NKA with extracellular α-syn assemblies reduce its pumping activity as its mutations in RDP/AHC.

Topics: alpha-Synuclein; Hemiplegia; Humans; Multiprotein Complexes; Mutation; Neurons; Parkinsonian Disorders; Sodium-Potassium-Exchanging ATPase

Prions are proteins that adopt alternative conformations that become self-propagating; the PrP(Sc) prion causes the rare human disorder Creutzfeldt-Jakob disease (CJD). We report here that multiple system atrophy (MSA) is caused by a different human prion composed of the α-synuclein protein. MSA is a slowly evolving disorder characterized by progressive loss of autonomic nervous system function and often signs of parkinsonism; the neuropathological hallmark of MSA is glial cytoplasmic inclusions consisting of filaments of α-synuclein. To determine whether human α-synuclein forms prions, we examined 14 human brain homogenates for transmission to cultured human embryonic kidney (HEK) cells expressing full-length, mutant human α-synuclein fused to yellow fluorescent protein (α-syn140*A53T-YFP) and TgM83(+/-) mice expressing α-synuclein (A53T). The TgM83(+/-) mice that were hemizygous for the mutant transgene did not develop spontaneous illness; in contrast, the TgM83(+/+) mice that were homozygous developed neurological dysfunction. Brain extracts from 14 MSA cases all transmitted neurodegeneration to TgM83(+/-) mice after incubation periods of ∼120 d, which was accompanied by deposition of α-synuclein within neuronal cell bodies and axons. All of the MSA extracts also induced aggregation of α-syn*A53T-YFP in cultured cells, whereas none of six Parkinson's disease (PD) extracts or a control sample did so. Our findings argue that MSA is caused by a unique strain of α-synuclein prions, which is different from the putative prions causing PD and from those causing spontaneous neurodegeneration in TgM83(+/+) mice. Remarkably, α-synuclein is the first new human prion to be identified, to our knowledge, since the discovery a half century ago that CJD was transmissible.

Topics: Aged; alpha-Synuclein; Animals; Brain; Exons; Female; HEK293 Cells; Humans; Immunohistochemistry; Male; Mice; Mice, Transgenic; Microscopy, Fluorescence; Middle Aged; Multiple System Atrophy; Neurodegenerative Diseases; Parkinsonian Disorders; Phosphorylation; Polymorphism, Single Nucleotide; Prions; Ubiquinone

Topics: alpha-Synuclein; Animals; Female; Humans; Male; Multiple System Atrophy; Parkinsonian Disorders; Prions

MicroRNAs (miRNAs) have been reported to be involved in degenerative disorders including Parkinson's disease (PD). α-synuclein expression is strong associated with the pathogenesis of PD. In the present study, we investigated whether the regulation of α-synuclein expression by miR-214 is the potential mechanism underlying the neuroprotective effect of Resveratrol.. The PD mouse model was established with the injection of MPTP (1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine) and the human neuroblastoma cell line, SH-SY5Y, was administrated with MPP+.. The midbrain of PD mice and MPP+ treated SH-SY5Y cells had the lower expression levels of miR-214 and higher mRNA and protein expression of α-synuclein, which were reversed by Resveratrol administration. MiR-214 mimic down-regulated expression of α-synuclein and its 3'-UTR activity, while the levels were up-regulated by miR-214 inhibitor. In addition, the cell viability, elevated by Resveratrol, was also decreased by miR-214 inhibitor or overexpressed α-synuclein. In vivo, miR-214 inhibitor down-regulated TH+ cells of ipsilateral and up-regulated α-synuclein expression compared with the group treated with Resveratrol.. The loss of miR-214 in PD resulted in the increase of α-synuclein expression, which was the potential mechanism underlying the neuroprotective effects of Resveratrol.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Cell Line, Tumor; Down-Regulation; Gene Expression Regulation; Humans; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Neuroblastoma; Neuroprotective Agents; Parkinsonian Disorders; Resveratrol; RNA, Messenger; Stilbenes; Up-Regulation

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

Topics: alpha-Synuclein; Hemiplegia; Humans; Mutation; Neurons; Parkinsonian Disorders; Sodium-Potassium-Exchanging ATPase

Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure (PAF) involve cytoplasmic deposition of α-synuclein and are considered to be synucleinopathies. Approximately 40% of patients with PD, most patients with MSA, and all patients with PAF have neurogenic orthostatic hypotension (OH). This study compared long-term survival in these synucleinopathies.. In this prospective cohort study, survival data were obtained for 97.6% of 206 referred patients evaluated between 1994 and 2014 (47 PD + OH, 54 PD no OH, 15 cerebellar MSA [MSA-C], 57 parkinsonian MSA [MSA-P], 28 PAF). Individual diagnoses were confirmed by clinical criteria and results of pharmacologic, neurochemical, and neuroimaging tests of sympathetic noradrenergic innervation. The Cox proportional hazard model was used to calculate hazard ratios (HRs) from symptom onset and from time of evaluation to death.. Patients with MSA-C or MSA-P had shorter survival from symptom onset than did patients with PD + OH (age- and sex-adjusted HR = 6.1, 5.6; p < 0.0001 each), PAF (HR = 10.8, 9.9; p < 0.0001 each) or PD no OH (HR = 14.9, 13.6; p < 0.0001 each). Among parkinsonian patients who died, median times from motor onset to death were 7.5 years in MSA-P, 11.6 years in PD + OH, and 15.8 years in PD no OH. Probabilities of survival for 10 years from onset of relevant symptoms were 0.39 in MSA-C, 0.33 in MSA-P, 0.74 in PD + OH, 0.87 in PAF, and 0.93 in PD no OH.. In synucleinopathies, survival depends on the particular disease, with the risk of death greater in MSA-P than in PD + OH and in PD + OH than in PD no OH.

Topics: Aged; alpha-Synuclein; Brain; Cerebellar Diseases; Cohort Studies; Dihydroxyphenylalanine; Female; Fluorine Radioisotopes; Humans; Longitudinal Studies; Male; Middle Aged; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders; Proportional Hazards Models; Prospective Studies; Pure Autonomic Failure; Radionuclide Imaging

Topics: alpha-Synuclein; Humans; Parkinsonian Disorders; Peptides; Protein Binding

Parkinson's disease (PD), the second most common neurodegenerative disease, impairs motor skills and cognitive function. To date, the drugs used for PD treatment provide only symptomatic relief. The identification of new drugs that show benefit in slowing the decline seen in PD patients is the focus of much current research. Acetylcorynoline is the major alkaloid component derived from Corydalis bungeana, a traditional Chinese medical herb. It has been shown to have anti-inflammatory properties, but no studies have yet described the effects of acetylcorynoline on PD. The aim of this study was to evaluate the potential for acetylcorynoline to improve PD in Caenorhabditis elegans models. In the present study, we used a pharmacological strain (BZ555) that expresses green fluorescent protein specifically in dopaminergic neurons, and a transgenic strain (OW13) that expresses human α-synuclein in muscle cells to study the antiparkinsonian effects of acetylcorynoline. Our experimental data showed that treatment with up to 10 mM acetylcorynoline does not cause toxicity in animals. Acetylcorynoline significantly decreases dopaminergic neuron degeneration induced by 6-hydroxydopamine in BZ555 strain; prevents α-synuclein aggregation; recovers lipid content in OW13 strain; restores food-sensing behavior, and dopamine levels; and prolongs life-span in 6-hydroxydopamine-treated N2 strain, thus showing its potential as a possible antiparkinsonian drug. Acetylcorynoline may exert its effects by decreasing egl-1 expression to suppress apoptosis pathways and by increasing rpn5 expression to enhance the activity of proteasomes.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antiparkinson Agents; Appetitive Behavior; Berberine Alkaloids; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Dopamine; Dopaminergic Neurons; Green Fluorescent Proteins; Humans; Molecular Structure; Muscle Cells; Nerve Degeneration; Oxidopamine; Parkinsonian Disorders; Repressor Proteins

Aging, the main risk factor for Parkinson's disease (PD), is associated with increased α-synuclein levels in substantia nigra pars compacta (SNc). Excess α-synuclein spurs Lewy-like pathology and dysregulates the activity of protein phosphatase 2A (PP2A). PP2A dephosphorylates many neuroproteins, including the catecholamine rate-limiting enzyme, tyrosine hydroxylase (TH). A loss of nigral dopaminergic neurons induces PD movement problems, but before those abnormalities occur, behaviors such as olfactory loss, anxiety, and constipation often manifest. Identifying mouse models with early PD behavioral changes could provide a model in which to test emerging therapeutic compounds. To this end, we evaluated mice expressing A53T mutant human (A53T) α-synuclein for behavior and α-synuclein pathology in olfactory bulb, adrenal gland, and gut. Aging A53T mice exhibited olfactory loss and anxiety that paralleled olfactory and adrenal α-synuclein aggregation. PP2A activity was also diminished in olfactory and adrenal tissues harboring insoluble α-synuclein. Low adrenal PP2A activity co-occurred with TH hyperactivity, making this the first study to link adrenal synucleinopathy to anxiety and catecholamine dysregulation. Aggregated A53T α-synuclein recombinant protein also had impaired stimulatory effects on soluble recombinant PP2A. Collectively, the data identify an excellent model in which to screen compounds for their ability to block the spread of α-synuclein pathology associated with pre-motor stages of PD.

Topics: Adrenal Glands; Aging; alpha-Synuclein; Animals; Anxiety; Blotting, Western; Brain Chemistry; Disease Progression; Food; Gastrointestinal Tract; Genotype; Hyperkinesis; Immunohistochemistry; Mice; Mice, Transgenic; Motor Activity; Neurons; Parkinsonian Disorders; Protein Phosphatase 2; Smell; Tyrosine 3-Monooxygenase

Protein aggregation and dysfunction of ubiquitin proteasome system (UPS) have been implicated in Parkinson's disease (PD) pathology for a long time. Heat shock proteins (HSPs) have neuro-protective effects in PD as they assist in protein refolding and targeting of irreparable proteins to UPS. To realize their benefits in a chronically progressing disease like PD, it is imperative to maintain slightly up-regulated levels of HSPs consistently over a longer period of time. Here, we evaluate the possible beneficial effects of HSP inducer carbenoxolone (cbx) in a rotenone-based rat model of PD. Simultaneously with rotenone, a low dose of cbx (20 mg/kg body weight) was administered for five weeks to male SD rats. Weekly behavioral analysis along with end-point evaluation of HSPs, UPS activity, apoptosis, and oxidative stress were performed. The activation of heat shock factor-1 (HSF-1) and up-regulation of HSP70, HSP40, and HSP27 levels in mid-brain following cbx administration resulted in the reduction of α-synuclein and ubiquitin aggregation. This decrease seems to be mediated by reduction in protein carbonylation as well as up-regulation of UPS activity. In addition, the decrease in apoptosis and oxidative stress following HSP upregulation prevented the decline in tyrosine hydroxylase (TH) and dopamine levels in mid-brain region, which in turn resulted in improved motor functions. Thus, persistent HSP induction at low levels by cbx could improve the PD pathophysiology.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Apoptosis; Carbenoxolone; DNA-Binding Proteins; Dopamine; Heat Shock Transcription Factors; Heat-Shock Proteins; Male; Mesencephalon; Motor Activity; Oxidative Stress; Parkinsonian Disorders; Random Allocation; Rats; Rats, Sprague-Dawley; Rotenone; Transcription Factors; Tyrosine 3-Monooxygenase; Ubiquitin

Mutations in ATP13A2 (PARK9) cause Kufor-Rakeb syndrome (KRS) characterized by juvenile-onset parkinsonism, pyramidal signs and dementia. PARK9 belongs to type 5 P-type ATPase with its putative function as a cation transporter. Loss of PARK9 leads to lysosomal dysfunction and subsequent α-synuclein (α-Syn) accumulation. However, the mechanistic link between PARK9 and lysosomal dysfunction remains unclear. Here, we found that patient fibroblasts expressing mutant PARK9 or primary neurons with silenced PARK9 exhibited increased sensitivity to extracellular zinc (Zn(2+)). This effect was rescued with the Zn(2+) chelators clioquinol or TPEN. PARK9-deficient cells showed decreased lysosomal sequestration of Zn(2+) and increased expression of zinc transporters. Importantly, increased concentrations of Zn(2+) (Zn(2+) stress) resulted in lysosomal dysfunction that was partially restored by expression of wild-type PARK9. Zn(2+) stress also caused increased expression of α-Syn and consequently decreased activity of the lysosomal enzyme glucocerebrosidase. Together, these data suggest that PARK9 loss of function leads to dyshomeostasis of intracellular Zn(2+) that in turn contributes to lysosomal dysfunction and accumulation of α-Syn. It will be of interest to examine whether therapeutic lowering of zinc may prove beneficial for patients with KRS.

Topics: alpha-Synuclein; Homeostasis; Humans; Lysosomes; Parkinsonian Disorders; Proton-Translocating ATPases; Zinc

Parkinson's disease is a neurodegenerative disorder, characterized by accumulation and misfolding of α-synuclein. Although the level of α-synuclein in neurons is fundamentally linked to the onset of neurodegeneration, multiple pathways have been implicated in its degradation, and it remains unclear which are the critical ubiquitination enzymes that protect against α-synuclein accumulation in vivo. The ubiquitin ligase Nedd4 targets α-synuclein to the endosomal-lysosomal pathway in cultured cells. Here we asked whether Nedd4-mediated degradation protects against α-synuclein-induced toxicity in the Drosophila and rodent models of Parkinson's disease. We show that overexpression of Nedd4 can rescue the degenerative phenotype from ectopic expression of α-synuclein in the Drosophila eye. Overexpressed Nedd4 in the Drosophila brain prevented the α-synuclein-induced locomotor defect whereas reduction in endogenous Nedd4 by RNAi led to worsening motor function and increased loss of dopaminergic neurons. Accordingly, AAV-mediated expression of wild-type but not the catalytically inactive Nedd4 decreased the α-synuclein-induced dopaminergic cell loss in the rat substantia nigra and reduced α-synuclein accumulation. Collectively, our data in two evolutionarily distant model organisms strongly suggest that Nedd4 is a modifier of α-synuclein pathobiology and thus a potential target for neuroprotective therapies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain; Dopaminergic Neurons; Drosophila; Endosomal Sorting Complexes Required for Transport; Eye; Female; Humans; Locomotion; Male; Mutation; Nedd4 Ubiquitin Protein Ligases; Nerve Degeneration; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; RNA, Messenger; Substantia Nigra; 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

There is an unmet need for biomarkers for Parkinson's disease (PD) and atypical parkinsonian disorders (APD). α-Synuclein, linked to the pathogenesis of PD, is a promising biomarker candidate in need of further investigation. The ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), a pivotal component of the ubiquitin proteasome system which seems to be disturbed in PD, may also be involved in the pathogenesis of this disorder.. We investigated cerebrospinal fluid (CSF) α-synuclein and UCH-L1 levels from 22 healthy controls, 52 patients with PD, 34 with multiple system atrophy (MSA), 32 with progressive supranuclear palsy, and 12 with corticobasal degeneration.. α-Synuclein levels were significantly decreased in PD and in MSA compared with controls, and in synucleinopathies compared with tauopathies. UCH-L1 levels were significantly decreased in PD, MSA as well as PSP compared with controls, and in PD compared with APD (p < 0.001). Both markers discriminated PD well from controls (p < 0.0001; area under the curve [AUC] = 0.82 and 0.89, respectively). Additionally, CSF α-synuclein separated patients with synucleinopathies from those with tauopathies (p = 0.015; AUC = 0.63), whereas CSF UCH-L1 discriminated between PD and APD (p = 0.0003; AUC = 0.69). Interestingly, α-synuclein and UCH-L1 levels were strongly correlated in PD and synucleinopathies, and weakly in tauopathies. No correlation was found in controls.. CSF levels of α-synuclein and UCH-L1 show distinct patterns in parkinsonian syndromes. Their combined determination may be useful in the differential diagnosis of parkinsonian disorders and provide key to understanding their pathoetiology and clinical course. Further large studies are needed to validate our findings.

Topics: Aged; alpha-Synuclein; Biomarkers; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Multiple System Atrophy; Parkinson Disease; Parkinsonian Disorders; Supranuclear Palsy, Progressive; Tauopathies; Ubiquitin Thiolesterase

Topics: Adult; alpha-Synuclein; Gene Rearrangement; Humans; Male; Mosaicism; Parkinsonian Disorders; Young Adult

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Benzodioxoles; Body Weight; Disease Progression; Disease-Free Survival; Female; Mice, Transgenic; Parkinsonian Disorders; Pyrazoles; Time Factors

Both the misfolding of α-synuclein and mitochondrial dysfunction are considered two major contributors to Parkinson's disease (PD). However, the relationship between the two in normal and PD states remains unclear. Here, we report that voltage-dependent anion channel 1 (VDAC1), a major component of the outer mitochondrial membrane known to regulate mitochondrial functions, is down-regulated in response to α-synuclein accumulation and aggregation. Stereological analysis revealed that 58.33% of the neurons were VDAC1 immunoreactive in the remaining neuromelanin laden neurons in the PD group while 87.48% of the nigral neurons were VDAC1 immunoreactive in the age-matched control group. The relative levels of VDAC1 were significantly decreased in PD nigral neurons when compared to age-matched controls. In PD, this decrease was significantly greater in nigral neurons with α-synuclein inclusions. VDAC1 was observed in fibers with granular α-synuclein but not in fibers with aggregated α-synuclein. Viral vector-mediated overexpression of mutant human α-synuclein (A30P) in rats resulted in significantly decreased VDAC1 in nigral neurons and striatal fibers. These results indicate that mitochondrial function associated with VDAC1 is decreased in sporadic and experimental PD, and this decrease is associated with α-synuclein accumulation and aggregation.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Brain; Corpus Striatum; Down-Regulation; Female; Humans; Male; Middle Aged; Mutation; Neurons; Parkinson Disease; Parkinsonian Disorders; Rats, Sprague-Dawley; Substantia Nigra; Voltage-Dependent Anion Channel 1

Cholesterol-oximes TRO19622 and TRO40303 target outer mitochondrial membrane proteins and have beneficial effects in preclinical models of neurodegenerative diseases leading to their advancement to clinical trials. Dopaminergic neurons degenerate in Parkinson's disease (PD) and are prone to oxidative stress and mitochondrial dysfunction. In order to provide insights into the neuroprotective potential of TRO19622 and TRO40303 for dopaminergic neurons in vivo, we assessed their effects on gene expression in laser captured nigrostriatal dopaminergic neurons of wildtype mice and of mice that over-express alpha-synuclein, a protein involved in both familial and sporadic forms of PD (Thy1-aSyn mice). Young mice were fed the drugs in food pellets or a control diet from 1 to 4months of age, approximately 10months before the appearance of striatal dopamine loss in this model. Unbiased weighted gene co-expression network analysis (WGCNA) of transcriptional changes revealed effects of cholesterol oximes on transcripts related to mitochondria, cytoprotection and anti-oxidant response in wild-type and transgenic mice, including increased transcription of stress defense (e.g. Prdx1, Prdx2, Glrx2, Hspa9, Pink1, Drp1, Trak1) and dopamine-related (Th, Ddc, Gch1, Dat, Vmat2, Drd2, Chnr6a) genes. Even at this young age transgenic mice showed alterations in transcripts implicated in mitochondrial function and oxidative stress (e.g. Bcl-2, Bax, Casp3, Nos2), and both drugs normalized about 20% of these alterations. Young Thy1-aSyn mice exhibit motor deficits that differ from parkinsonism and are established before the onset of treatment; these deficits were not improved by cholesterol oximes. However, high doses of TRO40303 improved olfaction and produced the same effects as dopamine agonists on a challenging beam test, specifically an increase in footslips, an observation congruent with its effects on transcripts involved in dopamine synthesis. High doses of TRO19622 increased alpha-synuclein aggregates in the substantia nigra; this effect, not seen with TRO40303 was inconsistent and may represent a protective mechanism as in other neurodegenerative diseases. Overall, the results suggest that cholesterol oximes, while not improving early effects of alpha-synuclein overexpression on motor behavior or pathology, may ameliorate the function and resilience of dopaminergic neurons in vivo and support further studies of neuroprotection in models with dopaminergic cell loss.

Topics: alpha-Synuclein; Animals; Brain; Cholestenones; Corpus Striatum; Dopamine Agonists; Dopaminergic Neurons; Gene Expression; Humans; Male; Mice, Transgenic; Movement Disorders; Neuroprotective Agents; Oximes; Parkinsonian Disorders; RNA, Messenger; Secosteroids; Substantia Nigra; Transcriptome

Several lines of evidence suggest that accumulation of aggregated alpha-synuclein (α-synuclein) in the central nervous system (CNS) is an early pathogenic event in Parkinson's disease and other Lewy body disorders. In recent years, animal studies have indicated immunotherapy with antibodies directed against α-synuclein as a promising novel treatment strategy. Since large α-synuclein oligomers, or protofibrils, have been demonstrated to possess pronounced cytotoxic properties, such species should be particularly attractive as therapeutic targets. In support of this, (Thy-1)-h[A30P] α-synuclein transgenic mice with motor dysfunction symptoms were found to display increased levels of α-synuclein protofibrils in the CNS. An α-synuclein protofibril-selective monoclonal antibody (mAb47) was evaluated in this α-synuclein transgenic mouse model. As measured by ELISA, 14month old mice treated for 14weeks with weekly intraperitoneal injections of mAb47 displayed significantly lower levels of both soluble and membrane-associated protofibrils in the spinal cord. Besides the lower levels of pathogenic α-synuclein demonstrated, a reduction of motor dysfunction in transgenic mice upon peripheral administration of mAb47 was indicated. Thus, immunotherapy with antibodies targeting toxic α-synuclein species holds promise as a future disease-modifying treatment in Parkinson's disease and related disorders.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Brain; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunization, Passive; Injections, Intraperitoneal; Male; Mice, Transgenic; Motor Activity; Mutation; Parkinsonian Disorders; Severity of Illness Index; Spinal Cord

We have developed a series of dihydroxy compounds and related analogues based on our hybrid D2/D3 agonist molecular template to develop multifunctional drugs for symptomatic and neuroprotective treatment for Parkinson's disease (PD). The lead compound (-)-24b (D-520) exhibited high agonist potency at D2/D3 receptors and produced efficacious activity in the animal models for PD. The data from thioflavin T (ThT) assay and from transmission electron microscopy (TEM) analysis demonstrate that D-520 is able to modulate aggregation of alpha-synuclein (αSN). Additionally, coincubation of D-520 with αSN is able to reduce toxicity of preformed aggregates of αSN compared to control αSN alone. Finally, in a neuroprotection study with dopaminergic MN9D cells, D-520 clearly demonstrated the effect of neuroprotection from toxicity of 6-hydroxydopamine. Thus, compound D-520 possesses properties characteristic of multifunctionality conducive to symptomatic and neuroprotective treatment of PD.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Cell Line, Tumor; Cell Survival; CHO Cells; Cricetulus; Dopamine Agonists; Dopaminergic Neurons; HEK293 Cells; Humans; Male; Mice; Molecular Structure; Neuroprotective Agents; Oxidopamine; Parkinsonian Disorders; Rats, Sprague-Dawley; Receptors, Dopamine D3; Reserpine

α-Synuclein (SNCA) locus duplications are associated with variable clinical features and reduced penetrance but the reasons underlying this variability are unknown.. To report a novel family carrying a heterozygous 6.4 Mb duplication of the SNCA locus with an atypical clinical presentation strongly reminiscent of frontotemporal dementia and late-onset pallidopyramidal syndromes and study phenotype-genotype correlations in SNCA locus duplications.. We report the clinical and neuropathologic features of a family carrying a 6.4 Mb duplication of the SNCA locus. To identify candidate disease modifiers, we completed a genetic analysis of the family and conducted statistical analysis on previously published cases carrying SNCA locus duplications using regression modeling with robust standard errors to account for clustering at the family level.. We assessed whether length of the SNCA locus duplication influences disease penetrance and severity and whether extraduplication factors have a disease-modifying role.. We identified a large 6.4 Mb duplication of the SNCA locus in this family. Neuropathological analysis showed extensive α-synuclein pathology with minimal phospho-tau pathology. Genetic analysis showed an increased burden of Parkinson disease-related risk factors and the disease-predisposing H1/H1 microtubule-associated protein tau haplotype. Statistical analysis of previously published cases suggested there is a trend toward increasing disease severity and disease penetrance with increasing duplication size. The corresponding odds ratios from the univariable analyses were 1.17 (95% CI, 0.81-1.68) and 1.34 (95% CI, 0.78-2.31), respectively. Sex was significantly associated with both disease risk and severity; men compared with women had increased disease risk and severity and the corresponding odds ratios from the univariable analyses were 8.36 (95% CI, 1.97-35.42) and 5.55 (95% CI, 1.39-22.22), respectively.. These findings further expand the phenotypic spectrum of SNCA locus duplications. Increased dosage of genes located within the duplicated region probably cannot increase disease risk and disease severity without the contribution of additional risk factors. Identification of disease modifiers accounting for the substantial phenotypic heterogeneity of patients with SNCA locus duplications could provide insight into molecular events involved in α-synuclein aggregation.

Topics: Age of Onset; alpha-Synuclein; Brain; Female; Frontotemporal Dementia; Gene Dosage; Gene Duplication; Genetic Association Studies; Genetic Loci; Genetic Predisposition to Disease; Humans; Microsatellite Repeats; Middle Aged; Odds Ratio; Parkinsonian Disorders; Pedigree; Penetrance; Risk Factors; Severity of Illness Index; Sex Factors

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are common neurodegenerative disorders of the aging population, characterized by progressive and abnormal accumulation of α-synuclein (α-syn). Recent studies have shown that C-terminus (CT) truncation and propagation of α-syn play a role in the pathogenesis of PD/DLB. Therefore, we explored the effect of passive immunization against the CT of α-syn in the mThy1-α-syn transgenic (tg) mouse model, which resembles the striato-nigral and motor deficits of PD. Mice were immunized with the new monoclonal antibodies 1H7, 5C1, or 5D12, all directed against the CT of α-syn. CT α-syn antibodies attenuated synaptic and axonal pathology, reduced the accumulation of CT-truncated α-syn (CT-α-syn) in axons, rescued the loss of tyrosine hydroxylase fibers in striatum, and improved motor and memory deficits. Among them, 1H7 and 5C1 were most effective at decreasing levels of CT-α-syn and higher-molecular-weight aggregates. Furthermore, in vitro studies showed that preincubation of recombinant α-syn with 1H7 and 5C1 prevented CT cleavage of α-syn. In a cell-based system, CT antibodies reduced cell-to-cell propagation of full-length α-syn, but not of the CT-α-syn that lacked the 118-126 aa recognition site needed for antibody binding. Furthermore, the results obtained after lentiviral expression of α-syn suggest that antibodies might be blocking the extracellular truncation of α-syn by calpain-1. Together, these results demonstrate that antibodies against the CT of α-syn reduce levels of CT-truncated fragments of the protein and its propagation, thus ameliorating PD-like pathology and improving behavioral and motor functions in a mouse model of this disease.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Brain; Disease Models, Animal; Humans; Immunotherapy; Mice; Mice, Transgenic; Movement Disorders; Parkinsonian Disorders; Tissue Distribution; Treatment Outcome

Alpha-synuclein (a-syn) is the major component of the intracytoplasmic inclusions known as Lewy bodies (LB), which constitute the hallmark of Parkinson's disease (PD). Mice overexpressing human a-syn under the Thy-1 promoter (ASO) show slow neurodegeneration and some behavioral deficits similar to those seen in human PD patients. Here, we describe a whole-brain distribution of human a-syn in adult ASO mice. We find that the human a-syn is ubiquitously distributed in the brain including the cerebellar cortex, but the intensity and sub-cellular localization of the staining differed in the various regions of the central nervous system. Among particular CNS areas with human a-syn immunoreactivity, we describe staining patterns in the olfactory bulb, cortex, hippocampus, thalamic region, brainstem nuclei and cerebellar cortex. This immunohistochemical study provides an anatomical map of the human a-syn distribution in ASO mice. Our data show that human a-syn, although not present at levels that were detectable by immunostaining in dopaminergic neurons of substantia nigra or noradrenergic neurons of locus coeruleus, was highly expressed in other PD relevant regions of the brain in different neuronal subtypes. These data will help to relate a-syn expression to the phenotypic manifestations observed in this widely used mouse line.

Topics: alpha-Synuclein; Animals; Brain; Female; Humans; Immunohistochemistry; Male; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Parkinsonian Disorders; Photomicrography; Promoter Regions, Genetic; Serotonin; Thy-1 Antigens; Tyrosine 3-Monooxygenase; Vesicular Inhibitory Amino Acid Transport Proteins

A broad range of microbial and amyloid proteins interact with cell surface glycolipids which behave as infectivity and/or toxicity cofactors in human pathologies. Here we have deciphered the biochemical code that determines the glycolipid-binding specificity of two major amyloid proteins, Alzheimer's β-amyloid peptide (Aβ) and Parkinson's disease associated protein α-synuclein. We showed that both proteins interact with selected glycolipids through a common loop-shaped motif exhibiting little sequence homology. This 12-residue domain corresponded to fragments 34-45 of α-synuclein and 5-16 of Aβ. By modulating the amino acid sequence of α-synuclein at only two positions in which we introduced a pair of histidine residues found in Aβ, we created a chimeric α-synuclein/Aβ peptide with extended ganglioside-binding properties. This chimeric peptide retained the property of α-synuclein to recognize GM3, and acquired the capacity to recognize GM1 (an Aβ-inherited characteristic). Free histidine (but not tryptophan or asparagine) and Zn2+ (but not Na+) prevented this interaction, confirming the key role of His-13 and His-14 in ganglioside binding. Molecular dynamics studies suggested that the chimeric peptide recognized cholesterol-constrained conformers of GM1, including typical chalice-shaped dimers, that are representative of the condensed cholesterol-ganglioside complexes found in lipid raft domains of the plasma membrane of neural cells. Correspondingly, the peptide had a particular affinity for raft-like membranes containing both GM1 and cholesterol. The chimeric peptide also interacted with several other gangliosides, including major brain gangliosides (GM4, GD1a, GD1b, and GT1b) but not with neutral glycolipids such as GlcCer, LacCer or asialo-GM1. It could inhibit the binding of Aβ1-42 onto neural SH-SY5Y cells and did not induce toxicity in these cells. In conclusion, deciphering the glycolipid code of amyloid proteins allowed us to create a universal ganglioside-binding peptide of only 12-residues with potential therapeutic applications in infectious and neurodegenerative diseases that involve cell surface gangliosides as receptors.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloidogenic Proteins; Cell Line, Tumor; Cell Membrane; Gangliosides; Glycolipids; Humans; Models, Molecular; Parkinsonian Disorders; Protein Binding

Molecular-level storage of environmental information in biological structures in tangible forms, and their subsequent transfer to the next generation, has been studied using the phenomenon of amyloidogenesis, which defines a biochemical condition generating highly ordered protein aggregates known as amyloid fibrils. α-Synuclein oligomers shown to experience unit assembly as the formation of amyloid fibrils were used in the present study as an environment-sensing agent. With temperature varying in 2 °C intervals between 37 °C and 43 °C, the oligomeric unit assembly led to fibrillar polymorphism from a straight to a curly appearance, as assessed using TEM and small-angle neutron scattering; the different effects on the secondary structures were evaluated using attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. The resulting diversified amyloid fibrils, which have distinctive molecular characteristics, were shown to be inherited by the next generation through the self-propagating property of amyloidogenesis. Storage of intangible temperature information in the diversified protein suprastructures and perpetuation of the stored information in the form of polymorphic amyloid fibrils could represent molecular inscription of environmental information into biological systems; this could further extend our understanding of any physiological/pathological significance of amyloidogenic polymorphism and be utilized in the area of nanobiotechnology to process various external signals.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Circular Dichroism; Humans; Nanotechnology; Parkinsonian Disorders; Protein Conformation; Protein Structure, Secondary; Spectroscopy, Fourier Transform Infrared; Temperature

Nitrosative stress mediated S-nitrosylation (SNO) of protein disulfide isomerase (PDI), a housekeeping oxidoreductase, has been implicated in the pathogenesis of sporadic Parkinson's (PD) and Alzheimer's (AD) diseases. Previous cell line studies have indicated that SNO-PDI formation provokes synphilin-1 aggregation, the minor Parkinsonian biomarker protein. Yet no work exists investigating whether SNO-PDI induces α-synuclein aggregation, the major Lewy body constituent associated with Parkinson's pathogenesis. Here, we report that SNO-PDI formation is linked to the aggregation of α-synuclein and also provokes α-synuclein:synphilin-1 deposits (Lewy-body-like debris) normally found in the PD brain. Furthermore, we have examined the ability of a small molecule, 2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione (ellagic acid; EA) to scavenge NOx radicals and to protect cells from SNO-PDI formation via rotenone insult both, cell-based and cell-independent in vitro experiments. Furthermore, EA not only mitigates nitrosative-stress-induced aggregation of synphilin-1 but also α-synuclein and α-synuclein:synphilin-1 composites (Lewy-like neurites) in PC12 cells. Mechanistic analyses of the neuroprotective phenomena revealed that EA lowered rotenone-instigated reactive oxygen species (ROS) and reactive nitrogen species (RNS) in PC12 cells, imparted antiapoptotic tributes, and directly interfered with SNO-PDI formation. Lastly, we demonstrate that EA can bind human serum albumin (HSA). These results collectively indicate that small molecules can provide a therapeutic foothold for overcoming Parkinson's through a prophylactic approach.

Topics: alpha-Synuclein; Animals; Carrier Proteins; Cell Nucleolus; Ellagic Acid; Endoplasmic Reticulum Stress; Gene Expression Regulation; HSP70 Heat-Shock Proteins; Humans; Nerve Tissue Proteins; Nitric Oxide; Parkinsonian Disorders; PC12 Cells; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Protein Binding; Protein Disulfide-Isomerases; Rats; Reactive Nitrogen Species; Reactive Oxygen Species; Rotenone

Kufor-Rakeb syndrome (KRS) is caused by loss-of-function mutations in ATP13A2 (PARK9) and characterized by juvenile-onset parkinsonism, pyramidal signs, and cognitive decline. Previous studies suggested that PARK9 deficiency causes lysosomal dysfunction and α-synuclein (α-syn) accumulation, whereas PARK9 overexpression suppresses toxicity of α-syn. However, the precise mechanism of PARK9 effect on lysosomes and α-syn has been unknown. Here, we found that overexpressed PARK9 localized to multivesicular bodies (MVBs) in the human H4 cell line. The results from patient fibroblasts showed that loss of PARK9 function leads to decreased number of the intraluminal vesicles in MVBs and diminished release of exosomes into culture media. By contrast, overexpression of PARK9 results in increased release of exosomes in H4 cells and mouse primary cortical neurons. Moreover, loss of PARK9 function resulted in decreased secretion of α-syn into extracellular space, whereas overexpressed PARK9 promotes secretion of α-syn, at least in part via exosomes. Finally, we found that PARK9 regulates exosome biogenesis through functional interaction with the endosomal sorting complex required for transport machinery. Together, these data suggest the involvement of PARK9 in the biogenesis of exosomes and α-syn secretion and raise a possibility that disruption of these pathways in patients with KRS contributes to the disease pathogenesis.

Topics: alpha-Synuclein; Animals; Cell Line; Cerebral Cortex; Endosomal Sorting Complexes Required for Transport; Exosomes; Humans; Male; Mice; Mutation; Neurons; Parkinsonian Disorders; Primary Cell Culture; Proton-Translocating ATPases

Topics: alpha-Synuclein; Animals; Brain; Gaucher Disease; Glucosylceramidase; Humans; Parkinsonian Disorders

Parkinson's disease (PD) is a neurodegenerative disease resulting from progressive loss of dopaminergic nigrostriatal neurons. α-Synuclein protein conformational changes, resulting in cytotoxic/aggregated proteins, have been linked to PD pathogenesis. We investigated a unilateral rotenone-lesioned mouse PD model. Unilateral lesion of the medial forebrain bundle for two groups of male C57 black mice (n=5); adult (6-12 months) group and aged (1.75-2 years) group, was via stereotactic rotenone injection. After 2 weeks post-lesion, phenotypic Parkinsonian symptoms, resting tremor, postural instability, left-handed bias, ipsiversive rotation and bradykinesia were observed and were more severe in the aged group. We investigated protein expression profiles of the post-translational modifier, SUMO-1, and α-synuclein between the treated and control hemisphere, and between adult and aged groups. Western analysis of the brain homogenates indicated that there were statistically significant (p<0.05) increases in several specific molecular weight species (ranging 12-190 kDa) of both SUMO-1 (0.75-4.3-fold increased) and α-synuclein (1.6-19-fold increase) in the lesioned compared to un-lesioned hemisphere, with the adult mice showing proportionately greater increases in SUMO-1 than the aged group.

Topics: Aging; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Male; Mice; Mice, Inbred C57BL; Parkinsonian Disorders; Rotenone; SUMO-1 Protein; Up-Regulation

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Brain; Female; Gaucher Disease; Glucosylceramidase; Humans; Lewy Body Disease; Male; Mutation; Parkinson Disease; Parkinsonian Disorders; Residence Characteristics

Parkinson's disease is a movement disorder characterized by death of dopaminergic substantia nigra (SN) neurons and brain accumulation of α-synuclein. The tyrosine kinase Abl is activated in neurodegeneration. Here, we show that lentiviral expression of α-synuclein in the mouse SN leads to Abl activation (phosphorylation) and lentiviral Abl expression increases α-synuclein levels, in agreement with Abl activation in PD brains. Administration of the tyrosine kinase inhibitor nilotinib decreases Abl activity and ameliorates autophagic clearance of α-synuclein in transgenic and lentiviral gene transfer models. Subcellular fractionation shows accumulation of α-synuclein and hyper-phosphorylated Tau (p-Tau) in autophagic vacuoles in α-synuclein expressing brains, but nilotinib enhances protein deposition into the lysosomes. Nilotinib is used for adult leukemia treatment and it enters the brain within US Food and Drug Administration approved doses, leading to autophagic degradation of α-synuclein, protection of SN neurons and amelioration of motor performance. These data suggest that nilotinib may be a therapeutic strategy to degrade α-synuclein in PD and other α-synucleinopathies.

Topics: Adult; alpha-Synuclein; Animals; Autophagy; Brain; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Genes, abl; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Parkinsonian Disorders; Point Mutation; Proto-Oncogene Proteins c-abl; Pyrimidines; Substantia Nigra

Multiplications of the SNCA gene that encodes alpha-synuclein are a rare cause of autosomal dominant Parkinson's disease (PD).. Here, we describe 2 novel families in which there is autosomal dominant PD associated with SNCA duplication, and we compare the clinical features of all known patients carrying 3 or 4 SNCA copies.. Affected members in family A presented with early onset PD that was variably associated with nonmotor features, such as dysautonomia, cognitive deficits, and psychiatric disturbances. In family B, the clinical presentation ranged from early onset PD-dementia with psychiatric disturbances to late onset PD with mild cognitive impairment.. The presence of 4 SNCA copies is associated with a rich phenotype, characterized by earlier onset of motor and nonmotor features compared with patients who bear 3 SNCA copies. The clinical spectrum associated with SNCA duplications is wide, even within a single family, suggesting a role for as yet unidentified genetic or environmental modifiers.

Topics: Adult; Aged; alpha-Synuclein; Female; Gene Duplication; Genetic Association Studies; Humans; Male; Middle Aged; Parkinsonian Disorders; Pedigree

Telmisartan (TEL), an angiotensin type 1 receptor (AT1R) antagonist, has been reported to exert neuroprotective effect in animal models of Parkinson's disease (PD). However, its effect on motor functions, mutant protein α-synuclein (SYN) and neurotrophic factors (BDNF and GDNF) expression and their interrelation in PD has not yet been elucidated. In the present study, the effect of TEL on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced motor dysfunctions and dopaminergic degeneration was ascertained through investigating the alterations in protein expression of dopamine transporter (DAT), tyrosine hydroxylase (TH) and SYN in C57BL/6J mouse. Further, the role of TEL on the gene expression of neurotrophic factors such as BDNF and GDNF and protein expression of vesicular monoamine transporter 2 (VMAT2) and Glial fibrillary acidic proteins (GFAP) were studied. In TEL treated mouse, strong negative correlation was observed between motor function and SYN, while a strong positive correlation was noted with BDNF and GDNF expression. TEL caused down-regulation of SYN, GFAP and up-regulation of DAT, TH, VAMT2, BDNF and GDNF expressions. Present data suggest that brain renin angiotensin system (RAS) plays a crucial role in motor function and in the regulation of key proteins such as SYN, BDNF and GDNF, DAT, TH, VMAT2 and GFAP in Parkinsonism. In conclusion, the present study shows that angiotensin type 1 receptor antagonists can ameliorate motor dysfunction and act as potential neuroprotective agent in the management of Parkinsonism.

Topics: alpha-Synuclein; Angiotensin II Type 1 Receptor Blockers; Animals; Behavior, Animal; Benzimidazoles; Benzoates; Brain-Derived Neurotrophic Factor; Corpus Striatum; Dopamine; Dopamine Plasma Membrane Transport Proteins; Gait; Gene Expression; Glial Cell Line-Derived Neurotrophic Factor; Glial Fibrillary Acidic Protein; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Neuroprotective Agents; Parkinsonian Disorders; Substantia Nigra; Telmisartan; Tyrosine 3-Monooxygenase; Vesicular Monoamine Transport Proteins

Aggregation of α-synuclein (ASYN) is considered a major determinant of neuronal loss in Parkinson's disease (PD). E6-associated protein (E6-AP), an E3 ubiquitin protein ligase, has been known to promote the degradation of α-synuclein. The aim of this study was to assess the effects of the sesquiterpene lactone reynosin on dopamine (DA)-induced neuronal toxicity and regulation of E6-associated protein and α-synuclein proteins in both in vitro and in vivo models of Parkinson's disease. Usi"ng flow cytometry and western blot analysis, we determined that reynosin significantly protected both against cell death from dopamine-induced toxicity in human neuroblastoma SH-SY5Y cells and against the loss of tyrosine hydroxylase (TH)-positive cells in 6-hydroxydopamine (6-OHDA)-lesioned rats (a rodent Parkinson's disease model system). In addition, reynosin made up-regulation of E6-associated protein expression and down-regulation of the over-expression of α-synuclein protein in both dopamine-treated SH-SY5Y cells and 6-hydroxydopamine-lesioned rats. These results suggest that the protective effect of reynosin against dopamine-induced neuronal cell death may be due to the reciprocal up-regulation of E6-associated protein and down-regulation of α-synuclein protein expression.

Topics: alpha-Synuclein; Animals; Blotting, Western; Cell Death; Cell Line; Down-Regulation; Flow Cytometry; Humans; Male; Neurons; Neuroprotective Agents; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Sesquiterpenes; Ubiquitin-Protein Ligases; Up-Regulation

The effects of ABL1/ABL inhibition on clearance of SNCA/α-synuclein were evaluated in animal models of α-synucleinopathies. Parkinson disease (PD) is a movement disorder characterized by death of dopaminergic substantia nigra (SN) neurons and brain accumulation of SNCA. The tyrosine kinase ABL1 is activated in several neurodegenerative diseases. An increase in ABL1 activity is detected in human postmortem PD brains. Lentiviral expression of SNCA in the mouse SN activates ABL1 via phosphorylation, while lentiviral Abl expression increases SNCA levels. Administration of the brain-penetrant tyrosine kinase inhibitor Nilotinib decreases Abl activity and facilitates autophagic clearance of SNCA in transgenic and lentiviral gene transfer models. Subcellular fractionation demonstrates accumulation of SNCA and hyperphosphorylated MAPT/Tau (p-MAPT) in autophagic vacuoles in SNCA-expressing brains, while Nilotinib treatment leads to protein deposition into the lysosomes, suggesting enhanced autophagic clearance. These data suggest that Nilotinib may be a therapeutic strategy to degrade SNCA in PD and other α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Autophagy; Dopamine; Dopaminergic Neurons; Humans; Male; Parkinsonian Disorders; Pyrimidines

The pathological end-state of Parkinson disease is well described from postmortem tissue, but there remains a pressing need to define early functional changes to susceptible neurons and circuits. In particular, mechanisms underlying the vulnerability of the dopamine neurons of the substantia nigra pars compacta (SNc) and the importance of protein aggregation in driving the disease process remain to be determined. To better understand the sequence of events occurring in familial and sporadic Parkinson disease, we generated bacterial artificial chromosome transgenic mice (SNCA-OVX) that express wild-type α-synuclein from the complete human SNCA locus at disease-relevant levels and display a transgene expression profile that recapitulates that of endogenous α-synuclein. SNCA-OVX mice display age-dependent loss of nigrostriatal dopamine neurons and motor impairments characteristic of Parkinson disease. This phenotype is preceded by early deficits in dopamine release from terminals in the dorsal, but not ventral, striatum. Such neurotransmission deficits are not seen at either noradrenergic or serotoninergic terminals. Dopamine release deficits are associated with an altered distribution of vesicles in dopaminergic axons in the dorsal striatum. Aged SNCA-OVX mice exhibit reduced firing of SNc dopamine neurons in vivo measured by juxtacellular recording of neurochemically identified neurons. These progressive changes in vulnerable SNc neurons were observed independently of overt protein aggregation, suggesting neurophysiological changes precede, and are not driven by, aggregate formation. This longitudinal phenotyping strategy in SNCA-OVX mice thus provides insights into the region-specific neuronal disturbances preceding and accompanying Parkinson disease.

Topics: Aging; alpha-Synuclein; Animals; Chromosomes, Artificial, Bacterial; Corpus Striatum; Dopaminergic Neurons; Humans; Mice; Parkinsonian Disorders; Substantia Nigra; Synaptic Transmission

Rat models of Parkinson's disease are widely used to elucidate the mechanisms underlying disease etiology or to investigate therapeutic approaches. Models were developed using toxins such as MPTP or 6-OHDA to specifically target dopaminergic neurons resulting in acute neuronal loss in the substantia nigra or by using viral vectors to induce the specific and gradual expression of alpha synuclein in the substantia nigra. The detection of alpha- synuclein oligomers, the presumed toxic species, in these models and others has been possible using only indirect biochemical approaches to date. Here we coinjected AAVs encoding alpha-synuclein fused to the N- or C-terminal half of VenusYFP in rat substantia nigra pars compacta and describe for the first time a novel viral vector rodent model with the unique ability to directly detect and track alpha synuclein oligomers ex vivo and in vivo.. Viral coinjection resulted in widespread VenusYFP signal within the nigrostriatal pathway, including cell bodies in the substantia nigra and synaptic accumulation in striatal terminals, suggestive of in vivo alpha-synuclein oligomers formation. Transduced rats showed alpha-synuclein induced dopaminergic neuron loss in the substantia nigra, the appearance of dystrophic neurites, and gliosis in the striatum. Moreover, we have applied in vivo imaging techniques in the living mouse to directly image alpha-synuclein oligomers in the cortex.. We have developed a unique animal model that provides a tool for the Parkinson's disease research community with which to directly detect alpha- synuclein oligomers in vivo and screen therapeutic approaches targeting alpha-synuclein oligomers.

Topics: alpha-Synuclein; Animals; Bacterial Proteins; Corpus Striatum; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Genetic Vectors; Gliosis; Humans; Luminescent Proteins; Mice, Inbred C57BL; Neural Pathways; Neuroimmunomodulation; Parkinsonian Disorders; Rats, Sprague-Dawley; Substantia Nigra

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. An inflammatory reaction seems to be involved in the pathological process in PD. Prospective clinical studies with various nonsteroidal anti-inflammatory drugs (NSAIDs) have shown that ibuprofen decreases the risk of PD. In the present study we investigated the influence of ibuprofen on dopaminergic neuron injury in the mice model of PD.. Twelve-month-old male C57Bl mice were injected with MPTP together with various doses of ibuprofen (10, 30 or 50 mg/kg), administered 1 h before MPTP injection for 7 consecutive days. Evaluation concerned dopamine content in the striatum, tyrosine hydroxylase (TH) protein and α-synuclein expression measured 7 and 21 days post MPTP administration (dpa).. MPTP caused injury to dopaminergic neuron endings in the striatum: dopamine content decreased by about 0% 7 dpa and by 85% 21 dpa; TH protein expression diminished by 21% 7 dpa; α-synuclein level decreased by 10 and 26% 7 and 21 dpa, respectively. Ibuprofen administration to mice treated with MPTP significantly increased the level of dopamine in the striatum 7 and 21 dpa. It also prevented TH protein decrease and increased α-synuclein level 21 dpa.. Ibuprofen was shown to protect neurons against MPTP-induced injury in the striatum. The possible mechanism of the neuroprotective effect of ibuprofen might be associated with decreased dopamine turnover and cyclooxygenases inhibition resulting in lower reactive oxygen species formation.

Topics: alpha-Synuclein; Animals; Anti-Inflammatory Agents, Non-Steroidal; Basal Ganglia; Cytoprotection; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Ibuprofen; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Neurons; Neuroprotective Agents; Parkinsonian Disorders; Time Factors; Tyrosine 3-Monooxygenase

The detection of Parkinson's disease (PD) in its preclinical stages prior to outright neurodegeneration is essential to the development of neuroprotective therapies and could reduce the number of misdiagnosed patients. However, early diagnosis is currently hampered by lack of reliable biomarkers. (1) H magnetic resonance spectroscopy (MRS) offers a noninvasive measure of brain metabolite levels that allows the identification of such potential biomarkers. This study aimed at using MRS on an ultrahigh field 14.1 T magnet to explore the striatal metabolic changes occurring in two different rat models of the disease. Rats lesioned by the injection of 6-hydroxydopamine (6-OHDA) in the medial-forebrain bundle were used to model a complete nigrostriatal lesion while a genetic model based on the nigral injection of an adeno-associated viral (AAV) vector coding for the human α-synuclein was used to model a progressive neurodegeneration and dopaminergic neuron dysfunction, thereby replicating conditions closer to early pathological stages of PD. MRS measurements in the striatum of the 6-OHDA rats revealed significant decreases in glutamate and N-acetyl-aspartate levels and a significant increase in GABA level in the ipsilateral hemisphere compared with the contralateral one, while the αSyn overexpressing rats showed a significant increase in the GABA striatal level only. Therefore, we conclude that MRS measurements of striatal GABA levels could allow for the detection of early nigrostriatal defects prior to outright neurodegeneration and, as such, offers great potential as a sensitive biomarker of presymptomatic PD.

Topics: alpha-Synuclein; Animals; Biomarkers; Brain; Early Diagnosis; Female; gamma-Aminobutyric Acid; Magnetic Resonance Spectroscopy; Oxidopamine; Parkinsonian Disorders; Protons; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity

In Parkinson's disease (PD), alpha-synuclein (AS) aggregates occur frequently in peripheral autonomic nervous system (pANS). Their presence in asymptomatic subjects suggests incidental Lewy-body disease (iLBD) that is thought to reflect pre-clinical PD. Cardiac involvement has been detected in post-mortem studies in both, PD and also in iLBD. In vivo documentation of cardiac AS pathology is lacking.. To prospectively assess the presence of AS aggregates in epicardial fat tissue from living subjects without parkinsonism undergoing elective cardiac surgery.. Epicardial fat tissue obtained during cardiac surgery from 91 subjects was studied by histology and immunohistochemistry. Areas more likely to contain pANS elements were selected. PD-related motor and non-motor symptoms (NMS) were assessed immediately before or after surgery.. Small autonomic nerves, ganglia and/or tyrosine-hydroxylase positive fibres were identified in epicardial fat in each of the 91 subjects (62 male/29 female, mean age 67 years). AS aggregates were detected in 7 subjects (7.7%), and were more frequent in those aged above 70 years. In AS-positive subjects constipation and acting dreams were significantly more frequent than in the AS-negative ones.. AS aggregates occur in epicardial pANS in subjects without parkinsonism, suggesting the diagnosis of iLBD. The presence in some of these subjects of non-motor symptoms such as acting dreams and constipation known to occur in premotor PD supports this interpretation. Adequate follow-up of the subjects in this study will indicate the time, if any, to progression to motor PD.

Topics: Adipose Tissue; Aged; Aged, 80 and over; alpha-Synuclein; Autonomic Nervous System; Female; Heart; Humans; Lewy Body Disease; Male; Middle Aged; Parkinsonian Disorders; Prospective Studies; Tyrosine 3-Monooxygenase

Parkinson's disease (PD), the second most common neurodegenerative disorder, is etiologically heterogeneous, with most cases thought to arise from a combination of environmental factors and genetic predisposition; about 10% of cases are caused by single gene mutations. While neurotoxin models replicate many of the key behavioral and neurological features, they often have limited relevance to human exposures. Genetic models replicate known disease-causing mutations, but are mostly unsuccessful in reproducing major features of PD. In this study, we created a BAC (bacterial artificial chromosome) transgenic rat model of PD expressing the E46K mutation of α-synuclein, which is pathogenic in humans. The mutant protein was expressed at levels ~2-3-fold above endogenous α-synuclein levels. At 12 months of age, there was no overt damage to the nigrostriatal dopamine system; however, (i) alterations in striatal neurotransmitter metabolism, (ii) accumulation and aggregation of α-synuclein in nigral dopamine neurons, and (iii) evidence of oxidative stress suggest this model replicates several preclinical features of PD. Further, when these animals were exposed to rotenone, a mitochondrial toxin linked to PD, they showed heightened sensitivity, indicating that α-synuclein expression modulates the vulnerability to mitochondrial impairment. We conclude that these animals are well-suited to examination of gene-environment interactions that are relevant to PD.

Topics: alpha-Synuclein; Animals; Chromosomes, Artificial, Bacterial; Disease Models, Animal; Female; Humans; Male; Mitochondria; Parkinsonian Disorders; Pregnancy; Rats; Rats, Transgenic; Rotenone

Parkinson's disease (PD) is a motor disorder that involves death of dopaminergic neurons in the substantia nigra pars compacta. Parkin is an autosomal recessive gene that is mutated in early onset PD. We investigated the role of parkin and autophagic clearance in postmortem nigrostriatal tissues from 22 non-familial sporadic PD patients and 15 control samples. Parkin was insoluble with altered cytosolic expression in the nigrostriatum of sporadic PD. Parkin insolubility was associated with lack of degradation of ubiquitinated proteins and accumulation of α-Synuclein and parkin in autophagosomes, suggesting autophagic defects in PD. To test parkin's role in mediating autophagic clearance, we used lentiviral gene transfer to express human wild type or mutant parkin (T240R) with α-Synuclein in the rat striatum. Lentiviral expression of α-Synuclein led to accumulation of autophagic vacuoles, while co-expression of parkin with α-Synuclein facilitated autophagic clearance. Subcellular fractionation showed accumulation of α-Synuclein and tau hyper-phosphorylation (p-Tau) in autophagosomes in gene transfer models, similar to the effects observed in PD brains, but parkin expression led to protein deposition into lysosomes. However, parkin loss of function mutation did not affect autophagic clearance. Taken together, these data suggest that functional parkin regulates autophagosome clearance, while decreased parkin solubility may alter normal autophagy in sporadic PD.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Autophagy; Corpus Striatum; Female; Humans; Male; Mesencephalon; Middle Aged; Mutation; Parkinsonian Disorders; Phosphorylation; Rats; Rats, Sprague-Dawley; Solubility; tau Proteins; Ubiquitin-Protein Ligases; Vacuoles

Mutations of GBA1, the gene encoding glucocerebrosidase, represent a common genetic risk factor for developing the synucleinopathies Parkinson disease (PD) and dementia with Lewy bodies. PD patients with or without GBA1 mutations also exhibit lower enzymatic levels of glucocerebrosidase in the central nervous system (CNS), suggesting a possible link between the enzyme and the development of the disease. Previously, we have shown that early treatment with glucocerebrosidase can modulate α-synuclein aggregation in a presymptomatic mouse model of Gaucher-related synucleinopathy (Gba1(D409V/D409V)) and ameliorate the associated cognitive deficit. To probe this link further, we have now evaluated the efficacy of augmenting glucocerebrosidase activity in the CNS of symptomatic Gba1(D409V/D409V) mice and in a transgenic mouse model overexpressing A53T α-synuclein. Adeno-associated virus-mediated expression of glucocerebrosidase in the CNS of symptomatic Gba1(D409V/D409V) mice completely corrected the aberrant accumulation of the toxic lipid glucosylsphingosine and reduced the levels of ubiquitin, tau, and proteinase K-resistant α-synuclein aggregates. Importantly, hippocampal expression of glucocerebrosidase in Gba1(D409V/D409V) mice (starting at 4 or 12 mo of age) also reversed their cognitive impairment when examined using a novel object recognition test. Correspondingly, overexpression of glucocerebrosidase in the CNS of A53T α-synuclein mice reduced the levels of soluble α-synuclein, suggesting that increasing the glycosidase activity can modulate α-synuclein processing and may modulate the progression of α-synucleinopathies. Hence, increasing glucocerebrosidase activity in the CNS represents a potential therapeutic strategy for GBA1-related and non-GBA1-associated synucleinopathies, including PD.

Topics: alpha-Synuclein; Animals; Brain; Dependovirus; Disease Models, Animal; Gaucher Disease; Glucosylceramidase; Hippocampus; Humans; Memory; Mice; Mice, Transgenic; Parkinsonian Disorders; Protein Structure, Quaternary; Psychosine; tau Proteins

It has been suggested that DNA vaccine plays a protective effect on degenerative diseases in the central nervous system (CNS), the Parkinson's disease (PD) included. In this study, we assessed the immune effects of optimized DNA vaccine (pVAX1-IL-4/SYN-B) in the C57BL/6 mice by ELISA, and immunohistochemistry. We also evaluated the neuroprotective effect of pVAX1-IL-4/SYN-B in MPTP model of Parkinson's disease, using behavioral methods, immunohistochemistry and western blot. We found that alphα-synuclein (α-syn) antibody significantly increased, IL-4 increased and IFN-r reduced in the serum of immunized C57BL/6 mice in optimized DNA vaccine group. The immune serum of mice specifically combined with the α-syn positive inclusion bodies in the brain of PD model mice. The preventive immunization with optimized DNA vaccine made the motor symptoms improved significantly, the apoptosis of tyrosine hydroxylase (TH) neuron and cyclooxygenase-2 (COX-2) expression significantly decreased in MPTP model mice. These results suggest that optimized DNA vaccine can make immunized mice produce high titers of specific α-syn antibody, mainly causing the humoral immune response; preventive immunization with optimized DNA vaccine can play neuroprotective and anti-inflammatory effects on mice suffering from the sub-acute MPTP Parkinson's disease.

Topics: alpha-Synuclein; Animals; Autoantibodies; Blotting, Western; Cytokines; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Immunohistochemistry; Mice; Mice, Inbred C57BL; Parkinsonian Disorders; Vaccines, DNA

Mutations in ATP13A2 (PARK9), encoding a lysosomal P-type ATPase, are associated with both Kufor-Rakeb syndrome (KRS) and neuronal ceroid lipofuscinosis (NCL). KRS has recently been classified as a rare genetic form of Parkinson's disease (PD), whereas NCL is a lysosomal storage disorder. Although the transport activity of ATP13A2 has not been defined, in vitro studies show that its loss compromises lysosomal function, which in turn is thought to cause neuronal degeneration. To understand the role of ATP13A2 dysfunction in disease, we disrupted its gene in mice. Atp13a2(-/-) and Atp13a2(+/+) mice were tested behaviorally to assess sensorimotor and cognitive function at multiple ages. In the brain, lipofuscin accumulation, α-synuclein aggregation and dopaminergic pathology were measured. Behaviorally, Atp13a2(-/-) mice displayed late-onset sensorimotor deficits. Accelerated deposition of autofluorescent storage material (lipofuscin) was observed in the cerebellum and in neurons of the hippocampus and the cortex of Atp13a2(-/-) mice. Immunoblot analysis showed increased insoluble α-synuclein in the hippocampus, but not in the cortex or cerebellum. There was no change in the number of dopaminergic neurons in the substantia nigra or in striatal dopamine levels in aged Atp13a2(-/-) mice. These results show that the loss of Atp13a2 causes sensorimotor impairments, α-synuclein accumulation as occurs in PD and related synucleinopathies, and accumulation of lipofuscin deposits characteristic of NCL, thus providing the first direct demonstration that null mutations in Atp13a2 can cause pathological features of both diseases in the same organism.

Topics: Adenosine Triphosphatases; Aging; alpha-Synuclein; Animals; Behavior, Animal; Brain; Dopaminergic Neurons; Feedback, Sensory; Humans; Membrane Proteins; Mice; Mice, Mutant Strains; Neuronal Ceroid-Lipofuscinoses; Parkinsonian Disorders; Proton-Translocating ATPases

Topics: alpha-Synuclein; Animals; Corpus Striatum; Lewy Bodies; Parkinsonian Disorders

A 65-year-old man presented with word-finding difficulty and gait disturbance. His speech was nonfluent with word retrieval impairment and difficulties with sentence repetition. Other cognitive domains were intact initially. He developed asymmetrical bradykinesia, rigidity and a rest tremor. Over the following 8 years, his speech production impairment slowly deteriorated with the development of a motor speech disorder, anomia, impaired repetition of single words as well as sentences, and impaired comprehension of initially sentences then single words. His parkinsonian syndrome also deteriorated with limited response to levodopa. Serial brain MRI revealed progressive asymmetric perisylvian atrophy. He died after a disease duration of 12 years. The clinical syndrome is discussed by an expert, the pathology is described, and important clinical points from the case are highlighted.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Aphasia, Primary Progressive; Brain; Gait Disorders, Neurologic; Humans; Longitudinal Studies; Magnetic Resonance Imaging; Male; Mental Status Schedule; Parkinsonian Disorders; tau Proteins; Writing

The 2 major types of neurodegeneration with brain iron accumulation (NBIA) are the pantothenate kinase type 2 (PANK2)-associated neurodegeneration (PKAN) and NBIA2 or infantile neuroaxonal dystrophy (INAD) due to mutations in the phospholipase A2, group VI (PLA2G6) gene. We have recently demonstrated clinical heterogeneity in patients with mutations in the PLA2G6 gene by identifying a poorly defined subgroup of patients who present late with dystonia and parkinsonism. We report the clinical and genetic features of 7 cases with PLA2G6 mutations. Brain was available in 5 cases with an age of death ranging from 8 to 36 years and showed widespread alpha-synuclein-positive Lewy pathology, which was particularly severe in the neocortex, indicating that the Lewy pathology spread corresponded to Braak stage 6 and was that of the "diffuse neocortical type". In 3 cases there was hyperphosphorylated tau accumulation in both cellular processes as threads and neuronal perikarya as pretangles and neurofibrillary tangles. Later onset cases tended to have less tau involvement but still severe alpha-synuclein pathology. The clinical and neuropathological features clearly represent a link between PLA2G6 and parkinsonian disorders.

Topics: Adolescent; Adult; alpha-Synuclein; Brain; Child; DNA Mutational Analysis; Dystonic Disorders; Female; Group VI Phospholipases A2; Humans; Lewy Bodies; Male; Mutation; Parkinsonian Disorders; Phenotype; tau Proteins

Chronic ingestion of yellow star thistle (Centaurea solstitialis) or Russian knapweed (Acroptilon repens) causes nigropallidal encephalomalacia (NPE) in horses with an abrupt onset of neurologic signs characterized by dystonia of lips and tongue, inability to prehend food, depression, and locomotor deficits. The objectives of this study were to reexamine the pathologic alterations of NPE and to conduct an immunohistochemistry study using antibodies to tyrosine hydroxylase and α-synuclein, to determine whether NPE brains show histopathologic features resembling those in human Parkinson disease. Results confirm that the NPE lesions are located within the substantia nigra pars reticulata, sparing the cell bodies of the dopaminergic neurons in the substantia nigra pars compacta, and in the rostral portion of the globus pallidus, with partial disruption of dopaminergic (tyrosine hydroxylase-positive) fibers passing through the globus pallidus. No abnormal cytoplasmic inclusions like the Lewy bodies of human Parkinson disease were seen in these NPE brains. These findings indicate that equine NPE may serve as a large animal model of environmentally acquired toxic parkinsonism, with clinical phenotype directly attributable to lesions in globus pallidus and substantia nigra pars reticulata rather than to the destruction of dopaminergic neurons.

Topics: alpha-Synuclein; Animals; Asteraceae; Brain; Centaurea; Disease Models, Animal; Encephalomalacia; Female; Globus Pallidus; Horse Diseases; Horses; Humans; Immunohistochemistry; Male; Parkinsonian Disorders; Phenotype; Plant Poisoning; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is the second most common neurodegenerative disorder. The presence of Lewy bodies is a major pathological change of PD. α-synuclein is the main component of Lewy bodies and is encoded by the SNCA gene. Mutations in the SNCA gene mainly result in rare familial forms of PD, while genetic variability in the SNCA gene modulates susceptibility to sporadic PD. Recent studies have suggested that levels of α-synuclein in extracellular biological fluid are associated with PD and implicated α-synuclein as a potential biomarker for PD diagnosis and severity. We studied serum α-synuclein concentration and two polymorphic variants of SNCA (Rep1 and rs11931074) in 110 sporadic PD patients and 136 controls. We further explored the influence of the two polymorphisms on the expression levels of serum α-synuclein. Soluble α-synuclein was detected in serum in all subjects, with no statistically significant difference between PD patients and controls (p = 0.611). Different Rep1 alleles and genotypes did not influence the expression of serum α-synuclein. The frequency of allele T of rs11931074 was significantly elevated in PD patients (p = 0.041), and was correlated with decreased serum α-synuclein in both dominant (p = 0.011) and additive (p = 0.008) models of association.

Topics: 3' Untranslated Regions; Adult; Aged; alpha-Synuclein; Case-Control Studies; Chi-Square Distribution; Female; Gene Frequency; Genetic Predisposition to Disease; Genotype; Humans; Lewy Bodies; Male; Middle Aged; Mutation; Parkinsonian Disorders; Statistics, Nonparametric

Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized by the loss of dopaminergic neurons from the substantia nigra pars compacta (SNpc). α-synuclein (αsyn) has been linked to the pathophysiology of PD, because of its mutations causing familial PD and its accumulation in brains of patients with familial and sporadic PD. Dopamine (DA) replacement is the most effective therapy for ameliorating the motor symptoms of PD; however, it remains controversial whether DA-replacement boosts regeneration in the dopaminergic system or accelerates disease progression and enhances neuronal loss. Here, we studied the effect of chronic L-DOPA treatment on dopaminergic neurons in wild-type (WT) and A30P αsyn transgenic mice after MPTP treatment. Acute MPTP intoxication induced degeneration of dopaminergic neurons in both WT and A30P αsyn transgenic mice. A strong regeneration of dopaminergic fibers at 90 days after MPTP was observed in WT mice. In contrast, regeneration was less pronounced in A30P αsyn mice. Chronic L-DOPA treatment after MPTP intoxication did not only reduce the regeneration of nigrostriatal fibers but also led to an increased apoptotic gene-expression profile in the SNpc and to a decline of TH-positive neurons in A30P αsyn. Our findings reveal that the presence of A30P αsyn inhibits the regeneration of nigrostriatal dopaminergic fibers, and that L-DOPA treatment might interact with the pathogenesis in PD.

Topics: alpha-Synuclein; Animals; Brain; Dopaminergic Neurons; Levodopa; Male; Mice; Mice, Knockout; Nerve Regeneration; Parkinsonian Disorders

Cycad seed consumption by the native islanders of Guam is frequently associated with high rates of amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS/PDC); furthermore, accompanying pathological examination often exhibits α-synuclein inclusions in the neurons of the affected brain. Acylated steryl-β-glucoside (ASG) contained in cycad seeds is considered as causative environmental risk factor. We aimed to investigate whether ASG influences aggregation and cell toxicity of α-synuclein. To understand whether ASG is a causative factor in the development of ALS/PDC, soybean-derived ASG was tested for its effect on in vitro aggregation of α-synuclein using Thioflavin-T. ASG was also tested to determine whether it modulates α-synuclein cytotoxicity in yeast cells. In addition, we determined whether an interaction between ASG and α-synuclein occurs in the plasma membrane or cytoplasm using three factors: GM1 ganglioside, small unilamellar vesicles, and ATP. In the present study, we found that ASG-mediated acceleration of α-synuclein aggregation is influenced by the presence of ATP, but not by the presence of GM1. ASG accelerated the α-synuclein aggregation in the cytoplasm. ASG also enhanced α-synuclein-induced cytotoxicity in yeast cells. This study demonstrated that ASG directly enhances aggregation and cytotoxicity of α-synuclein, which are often observed in patients with ALS/PDC. These results, using assays that replicate cytoplasmic conditions, are consistent with the molecular mechanism that cytotoxicity is caused by intracellular α-synuclein fibril formation in neuronal cells.

Topics: Adenosine Triphosphate; alpha-Synuclein; Amyotrophic Lateral Sclerosis; Cycas; Dementia; Glucosides; Humans; Neurotoxins; Parkinsonian Disorders; Proteostasis Deficiencies; Seeds; Unilamellar Liposomes

The aggregation of α-synuclein is connected to the pathology of Parkinson's disease and prolyl oligopeptidase (PREP) accelerates the aggregation of α-synuclein in vitro. The aim of this study was to investigate the effects of a PREP inhibitor, KYP-2047, on α-synuclein aggregation in cell lines overexpressing wild-type or A30P/A53T mutant human α-syn and in the brains of two A30P α-synuclein transgenic mouse strains.. Cells were exposed to oxidative stress and then incubated with the PREP inhibitor during or after the stress. Wild-type or transgenic mice were treated for 5 days with KYP-2047 (2 × 3 mg·kg(-1) a day). Besides immunohistochemistry and thioflavin S staining, soluble and insoluble α-synuclein protein levels were measured by Western blot. α-synuclein mRNA levels were quantified by PCR. The colocalization of PREP and α-synuclein,and the effect of KYP-2047 on cell viability were also investigated.. In cell lines, oxidative stress induced a robust aggregation of α-synuclein,and low concentrations of KYP-2047 significantly reduced the number of cells with α-synuclein inclusions while abolishing the colocalization of α-synuclein and PREP. KYP-2047 significantly reduced the amount of aggregated α-synuclein,and it had beneficial effects on cell viability. In the transgenic mice, a 5-day treatment with the PREP inhibitor reduced the amount of α-synuclein immunoreactivity and soluble α-synuclein protein in the brain.. The results suggest that the PREP may play a role in brain accumulation and aggregation of α-synuclein, while KYP-2047 seems to effectively prevent these processes.

Topics: alpha-Synuclein; Animals; Blotting, Western; Brain; Cell Culture Techniques; Cell Line, Tumor; Cell Survival; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Fluorescence; Motor Activity; Oxidative Stress; Parkinsonian Disorders; Proline; Prolyl Oligopeptidases; Reverse Transcriptase Polymerase Chain Reaction; Serine Endopeptidases; Serine Proteinase Inhibitors; Transfection

SNCA and MAPT genes and environmental factors are important risk factors of Parkinson's disease [PD], the second-most common neurodegenerative disease. The agrichemicals maneb and paraquat selectively target dopaminergic neurons, leading to parkinsonism, through ill-defined mechanisms. In the current studies we have analyzed the ability of maneb and paraquat, separately and together, to induce synucleinopathy and tauopathy in wild type mice. Maneb was ineffective in increasing α-synuclein [α-Syn] or p-Tau levels. By contrast, paraquat treatment of mice resulted in robust accumulation of α-Syn and hyperphosphorylation of Tau in striata, through activation of p-GSK-3β, a major Tau kinase. Co-treatment with maneb did not enhance the effects of paraquat. Increased hyperacetylation of α-tubulin was observed in paraquat-treated mice, suggesting cytoskeleton remodeling. Paraquat, but not maneb, inhibited soluble proteasomal activity on a peptide substrate but this was not associated with a decreased expression of 26S proteasome subunits. Both paraquat and maneb treatments increased levels of the autophagy inhibitor, mammalian target of rapamycin, mTOR, suggesting impaired axonal autophagy, despite increases in certain autophagic proteins, such as beclin 1 and Agt12. Autophagic flux was also impaired, as ratios of LC3 II to LC3 I were reduced in treated animals. Increased mTOR was also observed in postmortem human PD striata, where there was a reduction in the LC3 II to LC3 I ratio. Heat shock proteins were either increased or unchanged upon paraquat-treatment suggesting that chaperone-mediated autophagy is not hampered by the agrichemicals. These studies provide novel insight into the mechanisms of action of these agrichemicals, which indicate that paraquat is much more toxic than maneb, via its inhibitory effects on proteasomes and autophagy, which lead to accumulation of α-Syn and p-Tau.

Topics: alpha-Synuclein; Animals; Autophagy; Case-Control Studies; Corpus Striatum; Down-Regulation; Fungicides, Industrial; Herbicides; Humans; Male; Maneb; Mice; Mice, Inbred C57BL; Paraquat; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Signal Transduction; Tauopathies

Exposure to environmental neurotoxic metals, pesticides and other chemicals is increasingly recognized as a key risk factor in the pathogenesis of chronic neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. Oxidative stress and apoptosis have been actively investigated as neurotoxic mechanisms over the past two decades, resulting in a greater understanding of neurotoxic processes. Nevertheless, emerging evidence indicates that epigenetic changes, protein aggregation and autophagy are important cellular and molecular correlates of neurodegenerative diseases resulting from chronic neurotoxic chemical exposure. During the Joint Conference of the 13th International Neurotoxicology Association and the 11th International Symposium on Neurobehavioral Methods and Effects in Occupational and Environmental Health, the recent progress made toward understanding epigenetic mechanisms, protein aggregation, autophagy, and deregulated kinase activation following neurotoxic chemical exposure and the relevance to neurodegenerative conditions were one of the themes of the symposium. Dr. Anumantha G. Kanthasamy described the role of acetylation of histones and non-histone proteins in neurotoxicant-induced neurodegenerative processes in the nigral dopaminergic neuronal system. Dr. Arthi Kanthasamy illustrated the role of autophagy as a key determinant in cell death events during neurotoxic insults. Dr. Ajay Rana provided evidence for posttranslational modification of α-synuclein protein by the Mixed Linage Kinase (MLK) group of kinases to initiate protein aggregation in cell culture and animal models of Parkinson's disease. These presentations outlined emerging cutting edge mechanisms that might set the stage for future mechanistic investigations into new frontiers of molecular neurotoxicology. This report summarizes the views of symposium participants, with emphasis on future directions for study of environmentally and occupationally linked chronic neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Environmental Exposure; Environmental Pollutants; Epigenesis, Genetic; Gene Expression Regulation; Gene-Environment Interaction; Genetic Predisposition to Disease; Humans; Nerve Degeneration; Nervous System; Neurodegenerative Diseases; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Protein Kinases; Risk Assessment; Risk Factors; Signal Transduction

The autophagy-lysosomal pathway plays an important role in the clearance of long-lived proteins and dysfunctional organelles. Lysosomal dysfunction has been implicated in several neurodegenerative disorders including Parkinson's disease and related synucleinopathies that are characterized by accumulations of α-synuclein in Lewy bodies. Recent identification of mutations in genes linked to lysosomal function and neurodegeneration has offered a unique opportunity to directly examine the role of lysosomes in disease pathogenesis. Mutations in lysosomal membrane protein ATP13A2 (PARK9) cause familial Kufor-Rakeb syndrome characterized by early-onset parkinsonism, pyramidal degeneration and dementia. While previous data suggested a role of ATP13A2 in α-synuclein misfolding and toxicity, the mechanistic link has not been established. Here we report that loss of ATP13A2 in human fibroblasts from patients with Kufor-Rakeb syndrome or in mouse primary neurons leads to impaired lysosomal degradation capacity. This lysosomal dysfunction results in accumulation of α-synuclein and toxicity in primary cortical neurons. Importantly, silencing of endogenous α-synuclein attenuated the toxicity in ATP13A2-depleted neurons, suggesting that loss of ATP13A2 mediates neurotoxicity at least in part via the accumulation of α-synuclein. Our findings implicate lysosomal dysfunction in the pathogenesis of Kufor-Rakeb syndrome and suggest that upregulation of lysosomal function and downregulation of α-synuclein represent important therapeutic strategies for this disorder.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Cerebral Cortex; Dementia; Embryo, Mammalian; Epidermal Growth Factor; ErbB Receptors; Fibroblasts; Gene Expression Regulation; Green Fluorescent Proteins; Humans; L-Lactate Dehydrogenase; Leucine; Lysosomal-Associated Membrane Protein 1; Lysosomes; Male; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; Mutation; Neurofilament Proteins; Neurons; Parkinsonian Disorders; Proton-Translocating ATPases; RNA, Small Interfering; Statistics, Nonparametric; Time Factors; Transfection; Tritium

Parkinson disease (PD) is the second most common neurodegenerative disease, and it cannot be completely cured by current medications. In this study, DJ-1 protein was administrated into medial forebrain bundle of PD model rats those had been microinjected with 6-hydroxydopamine (6-OHDA) or MG-132. We found that DJ-1 protein could reduce apomorphine-induced rotations, inhibit reduction of dopamine contents and tyrosine hydroxylase levels in the striatum, and decrease dopaminergic neuron death in the substantia nigra. In 6-OHDA lesioned rats, uncoupling protein-4, uncoupling protein-5 and superoxide dismutase-2 (SOD2) mRNA and SOD2 protein were increased when DJ-1 protein was co-injected. Simultaneously, administration of DJ-1 protein reduced α-synuclein and hypoxia-inducible factor 1α mRNA and α-synuclein protein in MG-132 lesioned rats. Therefore, DJ-1 protein protected dopaminergic neurons in two PD model rats by increasing antioxidant capacity and inhibiting α-synuclein expression.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Apomorphine; Corpus Striatum; Dopamine; Dopaminergic Neurons; Drug Evaluation, Preclinical; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Intracellular Signaling Peptides and Proteins; Ion Channels; Leupeptins; Male; Microinjections; Mitochondrial Membrane Transport Proteins; Mitochondrial Proteins; Mitochondrial Uncoupling Proteins; Motor Activity; Nerve Tissue Proteins; Neuroprotective Agents; Oncogene Proteins; Oxidative Stress; Oxidopamine; Parkinsonian Disorders; Protein Deglycase DJ-1; Rats; Rats, Sprague-Dawley; Substantia Nigra; Superoxide Dismutase; Tyrosine 3-Monooxygenase

α-Synuclein pathology was examined in the brains and spinal cords of 10 patients with amyotrophic lateral sclerosis (ALS)/parkinsonism-dementia complex (PDC) in the Kii Peninsula, Japan. Various types of phosphorylated α-synuclein-positive structures including neuronal cytoplasmic inclusions, dystrophic neurites, and glial cytoplasmic inclusions were found in all ALS/PDC cases. There were phosphorylated α-synuclein-positive neurons in 8 cases (80%), and the amygdala was most severely affected. Phosphorylated α-synuclein was distributed mainly in the limbic system and brainstem; tau pathology was more prevalent than α-synuclein pathology in most affected areas. In the substantia nigra, periaqueductal gray, locus coeruleus, raphe nuclei, dorsal nucleus of the vagus nerve, hypoglossal nucleus or ventral horn, and intermediolateral nucleus of the spinal cord, α-synuclein pathology was more predominant than tau pathology in only 1 or 2 patients. Phosphorylated α-synuclein- positive structures were not found in the molecular layer of the cerebellum. Phosphorylated α-synuclein frequently colocalized with tau in neuron cell bodies, neurites, and glia. Immunoblots of sarkosyl-insoluble fractions extracted from the brain of 1 patient showed a triplet of α-synuclein-immunoreactive bands that were ubiquitinated. These results suggest that interaction between tau and α-synuclein be involved in the pathogenesis of Kii ALS/PDC.

Topics: Aged; alpha-Synuclein; Amyotrophic Lateral Sclerosis; Brain; Dementia; Female; Humans; Inclusion Bodies; Japan; Male; Middle Aged; Neurofibrillary Tangles; Neurons; Parkinsonian Disorders

The progressive loss of the nigrostriatal pathway is a distinguishing feature of Parkinson's disease. As terminal field loss seems to precede cell body loss, we tested whether alterations of axonal transport motor proteins would be early features in Parkinson's disease. There was a decline in axonal transport motor proteins in sporadic Parkinson's disease that preceded other well-known nigral cell-related pathology such as phenotypic downregulation of dopamine. Reductions in conventional kinesin levels precede the alterations in dopaminergic phenotypic markers (tyrosine hydroxylase) in the early stages of Parkinson's disease. This reduction was significantly greater in nigral neurons containing α-synuclein inclusions. Unlike conventional kinesin, reductions in the levels of the cytoplasmic dynein light chain Tctex type 3 subunit were only observed at late Parkinson's disease stages. Reductions in levels of conventional kinesin and cytoplasmic dynein subunits were recapitulated in a rat genetic Parkinson's disease model based on over-expression of human mutant α-synuclein (A30P). Together, our data suggest that α-synuclein aggregation is a key feature associated with reductions of axonal transport motor proteins in Parkinson's disease and support the hypothesis that dopaminergic neurodegeneration following a 'dying-back' pattern involving axonal transport disruption.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Axonal Transport; Case-Control Studies; Cytoplasmic Dyneins; Dopaminergic Neurons; Dyneins; Female; Humans; Kinesins; Male; Middle Aged; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Substantia Nigra; Tyrosine 3-Monooxygenase

α-Synuclein (α-syn) plays a prominent role in the degeneration of midbrain dopaminergic (mDA) neurons in Parkinson's disease (PD). However, only a few studies on α-syn have been performed in the mDA neurons in vivo, which may be attributed to a lack of α-syn transgenic mice that develop PD-like severe degeneration of mDA neurons. To gain mechanistic insights into the α-syn-induced mDA neurodegeneration, we generated a new line of tetracycline-regulated inducible transgenic mice that overexpressed the PD-related α-syn A53T missense mutation in the mDA neurons. Here we show that the mutant mice developed profound motor disabilities and robust mDA neurodegeneration, resembling some key motor and pathological phenotypes of PD. We also systematically examined the subcellular abnormalities that appeared in the mDA neurons of mutant mice and observed a profound decrease of dopamine release, the fragmentation of Golgi apparatus, and the impairments of autophagy/lysosome degradation pathways in these neurons. To further understand the specific molecular events leading to the α-syn-dependent degeneration of mDA neurons, we found that overexpression of α-syn promoted a proteasome-dependent degradation of nuclear receptor-related 1 protein (Nurr1), whereas inhibition of Nurr1 degradation ameliorated the α-syn-induced loss of mDA neurons. Given that Nurr1 plays an essential role in maintaining the normal function and survival of mDA neurons, our studies suggest that the α-syn-mediated suppression of Nurr1 protein expression may contribute to the preferential vulnerability of mDA neurons in the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Female; HEK293 Cells; Humans; Male; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation, Missense; Nerve Degeneration; Nuclear Receptor Subfamily 4, Group A, Member 2; Parkinsonian Disorders; Primary Cell Culture

Mutations in the parkin gene are currently thought to be the most common cause of recessive familial Parkinsonism. Parkin functions as an E3 ligase to regulate protein turnover, and its function in mitochondrial quality control has been reported recently. Overexpression of parkin has been found to prevent neuronal degeneration under various conditions both in vivo and in vitro. Here, we generated a transgenic mouse model in which expression of wild type parkin was driven by neuron-specific enolase (NSE) promoter. We reported that both young and old parkin transgenic mice exhibited less reduction of striatal TH protein and number of TH positive neurons in the substantia nigra induced by 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP), compared to wild type littermates. MPTP-induced mitochondrial impairment in the substantia nigra was improved in young parkin transgenic mice. Decreased striatal α-synuclein was demonstrated in old parkin transgenic mice. These results provide reliable evidence from the transgenic mouse model for parkin that overexpression of parkin may attenuate dopaminergic neurodegeneration induced by MPTP through protection of mitochondria and reduction of α-synuclein in the nigrostriatal pathway.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Dopamine; Dopaminergic Neurons; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitochondria; Neurodegenerative Diseases; Oncogene Proteins; Parkinsonian Disorders; Peroxiredoxins; Phosphopyruvate Hydratase; Promoter Regions, Genetic; Protein Deglycase DJ-1; Proto-Oncogene Proteins c-bcl-2; Substantia Nigra; Transcription, Genetic; Ubiquitin-Protein Ligases

Activation of the nuclear factor κB/c-Rel can increase neuronal resilience to pathological noxae by regulating the expression of pro-survival manganese superoxide dismutase (MnSOD, now known as SOD2) and Bcl-xL genes. We show here that c-Rel-deficient (c-rel(-/-)) mice developed a Parkinson's disease-like neuropathology with ageing. At 18 months of age, c-rel(-/-) mice exhibited a significant loss of dopaminergic neurons in the substantia nigra pars compacta, as assessed by tyrosine hydroxylase-immunoreactivity and Nissl staining. Nigral degeneration was accompanied by a significant loss of dopaminergic terminals and a significant reduction of dopamine and homovanillic acid levels in the striatum. Mice deficient of the c-Rel factor exhibited a marked immunoreactivity for fibrillary α-synuclein in the substantia nigra pars compacta as well as increased expression of divalent metal transporter 1 (DMT1) and iron staining in both the substantia nigra pars compacta and striatum. Aged c-rel(-/-) mouse brain were characterized by increased microglial reactivity in the basal ganglia, but no astrocytic reaction. In addition, c-rel(-/-) mice showed age-dependent deficits in locomotor and total activity and various gait-related deficits during a catwalk analysis that were reminiscent of bradykinesia and muscle rigidity. Both locomotor and gait-related deficits recovered in c-rel(-/-) mice treated with l-3,4-dihydroxyphenylalanine. These data suggest that c-Rel may act as a regulator of the substantia nigra pars compacta resilience to ageing and that aged c-rel(-/-) mice may be a suitable model of Parkinson's disease.

Topics: Aging; alpha-Synuclein; Animals; Cell Count; Corpus Striatum; Dopamine; Dopaminergic Neurons; Homovanillic Acid; Mice; Mice, Knockout; Motor Activity; NF-kappa B; Parkinsonian Disorders; Substantia Nigra

Parkinson's disease is characterized by abundant α-synuclein (α-Syn) neuronal inclusions, known as Lewy bodies and Lewy neurites, and the massive loss of midbrain dopamine neurons. However, a cause-and-effect relationship between Lewy inclusion formation and neurodegeneration remains unclear. Here, we found that in wild-type nontransgenic mice, a single intrastriatal inoculation of synthetic α-Syn fibrils led to the cell-to-cell transmission of pathologic α-Syn and Parkinson's-like Lewy pathology in anatomically interconnected regions. Lewy pathology accumulation resulted in progressive loss of dopamine neurons in the substantia nigra pars compacta, but not in the adjacent ventral tegmental area, and was accompanied by reduced dopamine levels culminating in motor deficits. This recapitulation of a neurodegenerative cascade thus establishes a mechanistic link between transmission of pathologic α-Syn and the cardinal features of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Corpus Striatum; Dopamine; Dopaminergic Neurons; Injections; Lewy Bodies; Mice; Parkinsonian Disorders; Protein Folding; Protein Transport; Recombinant Proteins; Substantia Nigra

Topics: Adult; Age of Onset; Aged; alpha-Synuclein; Female; Homozygote; Humans; Male; Middle Aged; Mutation; Parkinsonian Disorders; Pedigree; Polymorphism, Single Nucleotide

Interaction of genetic and environmental factors is likely involved in Parkinson's disease (PD). Mutations and multiplications of alpha-synuclein (α-syn) cause familial PD, and chronic manganese (Mn) exposure can produce an encephalopathy with signs of parkinsonism. We exposed male transgenic C57BL/6J mice expressing human α-syn or the A53T/A30P doubly mutated human α-syn under the tyrosine hydroxylase promoter and non-transgenic littermates to MnCl₂-enriched (1%) or control food, starting at the age of 4 months. Locomotor activity was increased by Mn without significant effect of the transgenes. Mice were sacrificed at the age of 7 or 20 months. Striatal Mn was significantly increased about three-fold in those exposed to MnCl₂. The number of tyrosine hydroxylase positive substantia nigra compacta neurons was significantly reduced in 20 months old mice (-10%), but Mn or transgenes were ineffective (three-way ANOVA with the factors gene, Mn and age). In 7 months old mice, striatal homovanillic acid (HVA)/dopamine (DA) ratios and aspartate levels were significantly increased in control mice with human α-syn as compared to non-transgenic controls (+17 and +11%, respectively); after Mn exposure both parameters were significantly reduced (-16 and -13%, respectively) in human α-syn mice, but unchanged in non-transgenic animals and mice with mutated α-syn (two-way ANOVA with factors gene and Mn). None of the parameters were changed in the 20 months old mice. Single HVA/DA ratios and single aspartate levels significantly correlated across all treatment groups suggesting a causal relationship between the rate of striatal DA metabolism and aspartate release. In conclusion, under our experimental conditions, Mn and human α-syn, wild-type and doubly mutated, did not interact to induce PD-like neurodegenerative changes. However, Mn significantly and selectively interacted with human wild-type α-syn on indices of striatal DA neurotransmission, the neurotransmitter most relevant to PD.

Topics: alpha-Synuclein; Animals; Blotting, Western; Chlorides; Chromatography, High Pressure Liquid; Corpus Striatum; Dopamine; Humans; Immunohistochemistry; Manganese Compounds; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Nerve Degeneration; Parkinsonian Disorders; Synaptic Transmission

Parkinson's disease (PD) is the second most prevalent late-onset neurodegenerative disorder that affects nearly 1% of the global population aged 65 and older. Whereas palliative treatments are in use, the goal of blocking progression of motor and cognitive disability remains unfulfilled. A better understanding of the basic pathophysiological mechanisms underlying PD would help to advance that goal. The present study provides evidence that brain ganglioside abnormality, in particular GM1, may be involved. This is based on use of the genetically altered mice with disrupted gene Galgt1 for GM2/GD2 synthase which depletes GM2/GD2 and all the gangliotetraose gangliosides that constitute the major molecular species of brain. These knockout mice show overt motor disability on aging and clear indications of motor impairment with appropriate testing at an earlier age. This disability was rectified by L-dopa administration. These mice show other characteristic symptoms of PD, including depletion of striatal dopamine (DA), loss of DA neurons of the substantia nigra pars compacta, and aggregation of alpha synuclein. These manifestations of parkinsonism were largely attenuated by administration of LIGA-20, a membrane permeable analog of GM1 that penetrates the blood brain barrier and enters living neurons. These results suggest that perturbation of intracellular mechanisms mediated by intracellular GM1 may be a contributing factor to PD.

Topics: Aged; alpha-Synuclein; Animals; Brain; Brain Chemistry; Female; Gangliosides; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurons; Neuropsychological Tests; Parkinsonian Disorders; Psychomotor Performance

Previous epidemiologic and genetic studies have suggested a link between Parkinson disease (PD), essential tremor (ET), and restless legs syndrome (RLS).. We describe the clinical, PET, and pathologic characteristics of an extensive kindred from Arkansas with hereditary PD, ET, and RLS. The pedigree contains 138 individuals. Sixty-five family members were examined neurologically up to 3 times from 2004 to 2010. Clinical data were collected from medical records and questionnaires. Genetic studies were performed. Five family members underwent multitracer PET. Two individuals with PD were examined postmortem.. Eleven family members had PD with generally mild and slowly progressive symptoms. Age at onset was between 39 and 74 years (mean 59.1, SD 13.4). All individuals treated with l-dopa responded positively. Postural or action tremor was present in 6 individuals with PD, and in 19 additional family members. Fifteen persons reported symptoms of RLS. PET showed reduced presynaptic dopamine function typical of sporadic PD in a patient with PD and ET, but not in persons with ET or RLS. The inheritance pattern was autosomal dominant for PD and RLS. No known pathogenic mutation in PD-related genes was found. Fourteen of the family members with PD, ET, or RLS had depression. Neuropathologic examination revealed pallidonigral pigment spheroid degeneration with ubiquitin-positive axonal spheroids, TDP43-positive pathology in the basal ganglia, hippocampus, and brainstem, and only sparse Lewy bodies.. Familial forms of PD, ET, RLS, and depression occur in this family. The genetic cause remains to be elucidated.

Topics: Adult; Aged; alpha-Synuclein; Brain; Depression; DNA-Binding Proteins; Dynactin Complex; Essential Tremor; Eukaryotic Initiation Factor-4G; Family Health; Female; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Longitudinal Studies; Male; Mental Status Schedule; Microtubule-Associated Proteins; Middle Aged; Parkinsonian Disorders; Positron-Emission Tomography; Protein Serine-Threonine Kinases; Restless Legs Syndrome

Effects of silencing ectopically expressed hSNCA in rat substantia nigra (SN) were examined as a novel therapeutic approach to Parkinson's disease (PD). AAV-hSNCA with or without an AAV harboring a short-hairpin (sh)RNA targeting hSNCA or luciferase was injected into one SN. At 9weeks, hSNCA-expressing rats had reduced SN dopamine (DA) neurons and exhibited a forelimb deficit. AAV-shRNA-SNCA silenced hSNCA and protected against the forelimb deficit. However, AAV-shRNA-SNCA also led to DA neuron loss suggesting undesirable effects of chronic shRNA expression. Effects on nigrostriatal-projecting neurons were examined using a retrograde tract tracer. Loss of striatal-projecting DA neurons was evident in the vector injection site, whereas DA neurons outside this site were lost in hSNCA-expressing rats, but not in hSNCA-silenced rats. These observations suggest that high levels of shRNA-SNCA were toxic to DA neurons, while neighboring neurons exposed to lower levels were protected by hSNCA gene silencing. Also, data collected on DA levels suggest that neurons other than or in addition to nigrostriatal DA neurons contributed to protection of forelimb use. Our observations suggest that while hSNCA gene silencing in DA neurons holds promise as a novel PD therapy, further development of silencing technology is required.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopamine; Forelimb; Gene Silencing; Genetic Therapy; Genetic Vectors; HEK293 Cells; Humans; Male; Neurons; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; RNA, Small Interfering; Treatment Outcome

Multiple laboratories have recently demonstrated that long-term dopaminergic transplants form Lewy bodies in patients with Parkinson's disease. Debate has arisen as to whether these Lewy bodies form from the transfer of α synuclein from the host to the graft or whether they form from intrinsic responses of the graft from being placed into what was, or became, an inflammatory focus. To test whether the former hypothesis was possible, we grafted fetal rat ventral mesencephalon into the dopamine depleted striatum of rats that had previously received 6-hydroxydopamine lesions. One month after the transplant, rats received viral over expression of human α synuclein (AAV2/6-α synuclein) or green fluorescent protein (AAV2/6-GFP) into the striatum rostral to the grafts. Care was taken to make sure that the AAV injections were sufficiently distal to the graft so no cells would be directly transfected. All rats were sacrificed five weeks after the virus injections. Double label immunohistochemistry combined with confocal microscopy revealed that a small number of grafted tyrosine hydroxylase (TH) neurons (5.7% ± 1.5% (mean ± SEM) of grafted dopamine cells) expressed host derived α synuclein but none of the grafted cells expressed host-derived GFP. The α synuclein in a few of these cells was misfolded and failed to be digested with proteinase K. These data indicate that it is possible for host derived α synuclein to transfer to grafted neurons supporting the concept that this is one possible mechanism by which grafted dopamine neurons form Lewy bodies in Parkinson's disease patients.

Topics: alpha-Synuclein; Animals; Dopamine; Fetal Tissue Transplantation; Graft Survival; Humans; Lewy Bodies; Male; Neurons; Oxidopamine; Parkinsonian Disorders; Rats; Rats, Inbred F344; Sympatholytics

Alpha-synuclein (α-SYN) is a small and highly conserved presynaptic protein that is implicated in both normal brain function and the pathogenesis of neurodegenerative diseases. Although the physiological function of α-SYN has not been fully evaluated, several lines of evidence suggest that it plays an important role in the regulation of dopamine homeostasis in the brain. Early studies have demonstrated that interaction of α-SYN and tyrosine hydroxylase (TH), a rate-limiting enzyme in dopamine synthesis, is functionally significant for dopaminergic neurotransmission and the pathophysiology of Parkinson's disease. In the present study, we would like to evaluate whether overexpression of wild-type or mutant α-SYN might affect cAMP/PKA-dependent TH activation in DA-producing SK-N-BE(2)C cells. Here we show that wild-type and mutant A30P and A53T α-SYN attenuate forskolin-induced TH up-regulation, but do not suppress TH basal expression in SK-N-BE(2)C cells. Forskolin-induced increase in TH promoter activity and CRE-dependent transcription are significantly suppressed in α-SYN-overexpressing cells. Alpha-SYN enters the nucleus, but does not bind to CREB or interfere with forskolin-induced CREB phosphorylation. These data indicate that elevated levels of α-SYN due to a specific disease or the normal aging process could be associated with dopaminergic neuronal dysfunction through interference with TH regulation.

Topics: alpha-Synuclein; Amino Acid Substitution; Cell Line; Cell Nucleus; Colforsin; Cyclic AMP; Cyclic AMP Response Element-Binding Protein; Cyclic AMP-Dependent Protein Kinases; Cytosol; Gene Expression Regulation; Genes, Reporter; Humans; Mutant Proteins; Neurons; Parkinsonian Disorders; Phosphorylation; Promoter Regions, Genetic; Protein Processing, Post-Translational; Protein Transport; Response Elements; Second Messenger Systems; Tyrosine 3-Monooxygenase

Lithium has recently been suggested to have neuroprotective properties in relation to several neurodegenerative diseases. In this study, we examined the potential cytoprotective effect of lithium in preventing oxidative stress-induced protein accumulation and neuronal cell death in the presence of increased α-synuclein levels in vitro and in vivo. Specifically, lithium administration was found to protect against cell death in a hydrogen peroxide-treated, stable α-synuclein-enhanced green fluorescent protein (EGFP)-overexpressing dopaminergic N27 cell line. Lithium feeding (0.255% lithium chloride) of 9-month-old pan-neuronal α-synuclein transgenic mice over a 3-month period was also sufficient to prevent accumulation of oxidized/nitrated α-synuclein as a consequence of chronic paraquat/maneb administration in multiple brain regions, including the glomerular layer, mitral cells, and the granule cell layer of the olfactory bulb (OB), striatum, substantia nigra pars compacta (SNpc) and Purkinje cells of the cerebellum. Lithium not only prevented α-synuclein-mediated protein accumulation/aggregation in these brain regions but also protected neuronal cells including mitral cells and dopaminergic SNpc neurons against oxidative stress-induced neurodegeneration. These results suggest that lithium can prevent both α-synuclein accumulation and neurodegeneration in an animal model of PD, suggesting that this drug, already FDA-approved for use in bipolar disorder, may constitute a novel therapy for another human disease.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Cell Death; Cell Line; Disease Models, Animal; Humans; Lithium Compounds; Mice; Mice, Transgenic; Neuroprotective Agents; Oxidative Stress; Parkinsonian Disorders

Mutations in the N-terminus of the gene encoding α-synuclein (α-syn) are linked to autosomal dominantly inherited Parkinson's disease (PD). The vast majority of PD patients develop neuropsychiatric symptoms preceding motor impairments. During this premotor stage, synucleinopathy is first detectable in the olfactory bulb (OB) and brain stem nuclei; however its impact on interconnected brain regions and related symptoms is still less far understood. Using a novel conditional transgenic mouse model, displaying region-specific expression of human mutant α-syn, we evaluated effect and reversibility of olfactory synucleinopathy. Our data showed that induction of mutant A30P α-syn expression increased transgenic deposition into somatodendritic compartment of dopaminergic neurons, without generating fibrillar inclusions. We found reversibly reduced levels of dopamine and metabolites in the OB, suggesting an impact of A30P α-syn on olfactory neurotransmitter content. We further showed that mutant A30P expression led to neurodegenerative changes on an ultrastructural level and a behaviorally hyperactive response correlated with novelty, odor processing and stress associated with an increased dopaminergic tone in midbrain regions. Our present data indicate that mutant (A30P) α-syn is directly implicated in reduction of dopamine signaling in OB interneurons, which mediates further alterations in brain regions without transgenic expression leading functionally to a hyperactive response. These modulations of neurotransmission may underlie in part some of the early neuropsychiatric symptoms in PD preceding dysfunction of the nigrostriatal dopaminergic system.

Topics: alpha-Synuclein; Amino Acid Substitution; Animals; Cricetinae; Disease Models, Animal; Dopamine; Female; Humans; Hyperkinesis; Male; Mice; Mice, Transgenic; Mutation; Neurons; Olfactory Bulb; Parkinsonian Disorders

The mechanisms underlying the chronic neurodegeneration that occurs in Parkinson's disease (PD) are unknown. One emerging hypothesis is that neural systems deteriorate and eventually degenerate due to a primary failure of either extrinsic neurotrophic support or the intrinsic cellular pathways that mediate such support. One of the cellular pathways that have been often identified in mediating neurotrophic effects is that of PI3K/Akt signaling. In addition, recent observations have suggested a primary failure of PI3K/Akt signaling in animal models and in PD patients. Therefore, to explore the possible role of endogenous Akt signaling in maintaining the viability and functionality of substantia nigra (SN) dopamine neurons, one of the principal systems affected in PD, we have used an adeno-associated viral vector to transduce them with a dominant negative (DN) form of Akt, the pleckstrin homology (PH) domain alone (DN(PH)-Akt). In addition, we have examined the effect of DN(PH)-Akt in murine models of two risk factors for human PD: advanced age and increased expression of α-synuclein. We find that transduction of these neurons in normal adult mice has no effect on any aspect of their morphology at 4 or 7weeks. However, in both aged mice and in transgenic mice with increased expression of human α-synuclein we observe decreased phenotypic expression of the catecholamine synthetic enzyme tyrosine hydroxylase (TH) in dopaminergic axons and terminals in the striatum. In aged transgenic α-synuclein over-expressing mice this reduction was 2-fold as great. We conclude that the two principal risk factors for human PD, advanced age and increased expression of α-synuclein, reveal a dependence of dopaminergic neurons on endogenous Akt signaling for maintenance of axonal phenotype.

Topics: Aging; alpha-Synuclein; Animals; Axons; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Parkinsonian Disorders; Proto-Oncogene Proteins c-akt; Signal Transduction

α-synuclein [α-Syn]-mediated activation of GSK-3β leading to increases in hyperphosphorylated Tau has been shown by us to occur in striata of Parkinson's diseased [PD] patients and in animal models of PD. In Alzheimer's disease, tauopathy exists in several brain regions; however, the pattern of distribution of tauopathy in other brain regions of PD or in animal models of PD is not known. The current studies were undertaken to analyze the distribution of tauopathy in different brain regions in a widely used mouse model of PD, the α-Syn overexpressing mouse.. High levels of α-Syn levels were seen in the brain stem, with a much smaller increase in the frontal cortex; neither cerebellum nor hippocampus showed any overexpression of α-Syn. Elevated levels of p-Tau, hyperphosphorylated at Ser202, Ser262 and Ser396/404, were seen in brain stem, with lower levels seen in hippocampus. In both frontal cortex and cerebellum, increases were seen only in p-Ser396/404 Tau, but not in p-Ser202 and p-Ser262. p-GSK-3β levels were not elevated in any of the brain regions, although total GSK-3β was elevated in brain stem. p-p38MAPK levels were unchanged in all brain regions examined, while p-ERK levels were elevated in brain stem, hippocampus and cerebellum, but not the frontal cortex. p-JNK levels were increased in brain stem and cerebellum but not in the frontal cortex or hippocampus. Elevated levels of free tubulin, indicating microtubule destabilization, were seen only in the brain stem.. Our combined data suggest that in this animal model of PD, tauopathy, along with microtubule destabilization, exists primarily in the brain stem and striatum, which are also the two major brain regions known to express high levels of α-Syn and undergo the highest levels of degeneration in human PD. Thus, tauopathy in PD may have a very restricted pattern of distribution.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Mice; Mice, Inbred C57BL; Multiple System Atrophy; Parkinsonian Disorders; Tauopathies; Tissue Distribution; Up-Regulation

In the healthy brain, less than 5% of α-synuclein (α-syn) is phosphorylated at serine 129 (Ser(P)-129). However, within Parkinson disease (PD) Lewy bodies, 89% of α-syn is Ser(P)-129. The effects of Ser(P)-129 modification on α-syn distribution and solubility are poorly understood. As α-syn normally exists in both membrane-bound and cytosolic compartments, we examined the binding and dissociation of Ser(P)-129 α-syn and analyzed the effects of manipulating Ser(P)-129 levels on α-syn membrane interactions using synaptosomal membranes and neural precursor cells from α-syn-deficient mice or transgenic mice expressing human α-syn. We first evaluated the recovery of the Ser(P)-129 epitope following either α-syn membrane binding or dissociation. We demonstrate a rapid turnover of Ser(P)-129 during both binding to and dissociation from synaptic membranes. Although the membrane binding of WT α-syn was insensitive to modulation of Ser(P)-129 levels by multiple strategies (the use of phosphomimic S129D and nonphosphorylated S129A α-syn mutants; by enzymatic dephosphorylation of Ser(P)-129 or proteasome inhibitor-induced elevation in Ser(P)-129; or by inhibition or stable overexpression of PLK2), PD mutant Ser(P)-129 α-syn showed a preferential membrane association compared with WT Ser(P)-129 α-syn. Collectively, these data suggest that phosphorylation at Ser-129 is dynamic and that the subcellular distribution of α-syn bearing PD-linked mutations, A30P or A53T, is influenced by the phosphorylation state of Ser-129.

Topics: alpha-Synuclein; Amino Acid Substitution; Animals; Cell Line; Epitopes; Humans; Lewy Bodies; Mice; Mice, Knockout; Mutation, Missense; Parkinsonian Disorders; Protein Binding; Protein Kinases; Protein Serine-Threonine Kinases; Protein Transport; Synaptic Membranes

The aim was to establish a non-primate large animal PD model by lentiviral vector mediated mutant alpha-synuclein overexpression in the substantia nigra. Lentivirus encoding A53T alpha-synuclein (6 x 2.5 μl) was stereotaxically injected into the substantia nigra of six adult female Göttingen minipigs. Contralateral control injections encoding enhanced green fluorescent protein (EGFP) were performed. Gait-analysis was performed pre- and postoperatively. PCR of the transgenes and immunohistochemical staining against alpha-synuclein, EGFP, GFAP and TH was performed after 20 weeks. Gait analysis revealed a significant increase in step length and height, and a decrease in the double stand phase. PCR verified the mesencephalic presence of transgenes. IHC analysis showed alpha-synuclein expression in nigral neurons, around the injection tract and in related nigrostriatal projections. The alpha-synuclein positive neurons appeared swollen and vacuolated, in contrast to the EGFP-injected control side. To transduct all nigrostriatal cells with few microinjections, wider dissemination of the transgene must be achieved.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Female; Gene Transfer Techniques; Genetic Vectors; Green Fluorescent Proteins; Magnetic Resonance Imaging; Neurons; Parkinsonian Disorders; Substantia Nigra; Swine; Swine, Miniature

Transgenic (Tg) mouse models of Parkinson's disease (PD) generated to date have primarily been designed to overexpress human alpha-synuclein (alpha-syn) to recapitulate PD-like motor impairments as well as PD-like nigrostriatal degeneration and alpha-syn pathology. However, cognitive impairments and cortical alpha-syn pathology are also common in PD patients. To model these features of PD, we created forebrain-specific conditional Tg mice that overexpress human wild type (WT) or A53T mutant alpha-syn. Here we show that both WT and A53T mutant alpha-syn lead to massive degeneration of postmitotic neurons in the hippocampal dentate gyrus (DG) during postnatal development, with hippocampal synapse loss as evidenced by reduced levels of pre- and postsynaptic markers. However, when mutant and WT alpha-syn expression was repressed until the Tg mice were mature postnatally and then induced for several months, no hippocampal neuron loss was observed. These data imply that developing neurons are more vulnerable to degenerate than mature neurons as a consequence of forebrain WT and mutant alpha-syn overexpression.

Topics: Age Factors; alpha-Synuclein; Animals; Animals, Newborn; Axons; Cell Death; Cell Proliferation; Disease Models, Animal; Doxycycline; Gene Expression Regulation, Developmental; Hippocampus; Humans; Mice; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Neurons; Parkinsonian Disorders; Prosencephalon; Synapses; Tubulin

The alpha-synuclein gene (SNCA) multiplication causes autosomal dominant Parkinson Disease (PD): triplication is associated with early-onset rapidly progressing parkinsonism with a strong likelihood of developing dementia, while duplication is associated with a less severe phenotype similar to idiopathic PD. We tested for SNCA multiplication 144 unrelated PD patients with a dominant family history. We identified one patient with SNCA duplication (0.7%). The SNCA-duplicated patient was a woman of 45 years of age with PD onset at 41 years of age. She experienced a rapidly progressive disease with early motor complications (on/off fluctuations and dyskinesias). Medical records confirmed that the proband's mother developed PD at 47 years of age and died at 63 with dementia. She experienced rapid progression in both motor and cognitive symptoms: development of dementia at 54 years of age, 7 years after onset. Although SNCA duplication is an unusual cause of familial PD testing for it is worthwhile. The clinical presentation of duplicated cases may be more aggressive than usual.

Topics: Adult; Aged; alpha-Synuclein; Family Health; Female; Gene Duplication; Genetic Predisposition to Disease; Genome-Wide Association Study; Humans; Italy; Male; Middle Aged; Parkinsonian Disorders; Young Adult

Predominantly, magnetic resonance imaging (MRI) studies in animal models of Parkinson's disease (PD) have focused on alterations in T2 water 1H relaxation or 1H MR spectroscopy (MRS), whilst potential morphological changes and their relationship to histological or behavioural outcomes have not been appropriately addressed. Therefore, in this study we have utilised MRI to scan in vivo brains from rodents bearing a nigrostriatal lesion induced by intranigral injection of the proteasome inhibitor lactacystin.. Lactacystin induced parkinsonian-like behaviour, characterised by impaired contralateral forelimb grip strength and increased contralateral circling in response to apomorphine. T2-weighted MRI, 3-weeks post-lesion, revealed significant morphological changes in PD-relevant brain areas, including the striatum and ventral midbrain in addition to a decrease in T2 water 1H relaxation in the substantia nigra (SN), but not the striatum. Post-mortem histological analyses revealed extensive dopaminergic neuronal degeneration and alpha-synuclein aggregation in the SN. However, extensive neuronal loss could also be observed in extra-nigral areas, suggesting non-specific toxicity of lactacystin. Iron accumulation could also be observed throughout the midbrain reflecting changes in T2. Importantly, morphological, but not T2 relaxivity changes, were significantly associated with both behavioural and histological outcomes in this model.. A pattern of morphological changes in lactacystin-lesioned animals has been identified, as well as alterations in nigral T2 relaxivity. The significant relationship of morphological changes with behavioural and histological outcomes in this model raises the possibility that these may be useful non-invasive surrogate markers of nigrostriatal degeneration in vivo.

Topics: Acetylcysteine; alpha-Synuclein; Animals; Apomorphine; Corpus Striatum; Cysteine Proteinase Inhibitors; Disease Models, Animal; Dopamine; Dopamine Agonists; Iron; Magnetic Resonance Imaging; Male; Mesencephalon; Motor Activity; Neurons; Parkinsonian Disorders; Random Allocation; Rats; Rats, Sprague-Dawley; Substantia Nigra

Although generally considered a prototypical movement disorder, Parkinson's disease is commonly associated with a broad-spectrum of non-motor symptoms, including autonomic dysfunctions caused by significant alterations in catecholaminergic neurons of the peripheral sympathetic nervous system. Here we present evidence that alpha-synuclein is highly expressed by sympathetic ganglion neurons throughout embryonic and postnatal life and that it is found in tyrosine hydroxylase-positive sympathetic fibers innervating the heart of adult mice. However, mice deficient in alpha-synuclein do not exhibit any apparent alterations in sympathetic development. Sympathetic neurons isolated from mouse embryos and early postnatal mice are sensitive to the parkinsonian drug MPTP/MPP(+) and intoxication requires entry of the neurotoxin through the noradrenaline transporter. Furthermore, recovery of noradrenaline from cardiac sympathetic fibers is reduced in adult mice treated with MPTP systemically. However, MPP(+)-induced sympathetic neuron loss in vitro or MPTP-induced cardiac noradrenaline depletion in vivo is not modified in mice lacking alpha-synuclein. This is in clear contrast with the observation that dopaminergic neurons of the central nervous system are significantly less vulnerable to MPTP/MPP(+) in the absence of alpha-synuclein, suggesting different actions of this molecule in central and peripheral catecholaminergic neurons.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Catecholamines; Cell Death; Cells, Cultured; Ganglia, Sympathetic; Mice; Mice, Mutant Strains; Nerve Degeneration; Neurons; Neurotoxins; Parkinsonian Disorders; Sympathetic Fibers, Postganglionic; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is generally sporadic but a number of genetic diseases have parkinsonism as a clinical feature. Two dominant genes, alpha-synuclein (SNCA) and leucine-rich repeat kinase 2 (LRRK2), are important for understanding inherited and sporadic PD. SNCA is a major component of pathologic inclusions termed Lewy bodies found in PD. LRRK2 is found in a significant proportion of PD cases. These two proteins may be linked as most LRRK2 PD cases have SNCA-positive Lewy bodies. Mutations in both proteins are associated with toxic effects in model systems although mechanisms are unclear. LRRK2 is an intracellular signaling protein possessing both GTPase and kinase activities that may contribute to pathogenicity. A third protein, tau, is implicated as a risk factor for PD. We discuss the potential relationship between these genes and suggest a model for PD pathogenesis where LRRK2 is upstream of pathogenic effects through SNCA, tau, or both proteins.

Topics: alpha-Synuclein; Genes, Dominant; Genetic Predisposition to Disease; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lewy Bodies; Mutation; Neurons; Parkinsonian Disorders; Protein Serine-Threonine Kinases; Signal Transduction; tau Proteins

Topics: Adult; Aged; alpha-Synuclein; Developing Countries; Genetic Testing; Humans; Middle Aged; Parkinsonian Disorders; Point Mutation; Ubiquitin; Ubiquitin-Protein Ligases

Over the past decade, major progress has been achieved in the identification of genes associated with Parkinson's disease (PD) and parkinsonism. Five genes have now been shown conclusively to play a role in PD susceptibility. Mutations in three of these genes, PRKN, PINK1, and DJ1, are important in early onset, recessively inherited PD, while mutations in LRRK2 and SNCA result in autosomal-dominant PD. LRRK2 has emerged as the most prevalent genetic cause of PD and has been implicated in both familial and sporadic forms of disease. In addition, autosomal-dominant dementia and Parkinsonism has been shown to be caused by mutations in the MAPT and PGRN genes. Molecular tests are now commercially available for several of these genes; however, in some of them, positive results need to be interpreted with caution until penetrance is better understood. In addition, clinical treatment of PD remains largely unaltered by the results of genetic testing.

Topics: alpha-Synuclein; Genetic Association Studies; Genetic Predisposition to Disease; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mutation; Neuroprotective Agents; Oncogene Proteins; Parkinson Disease; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; tau Proteins

Braak and colleagues have proposed a staging scheme for Parkinson's disease (PD) based on patterns of abnormal immunostaining for alpha-synuclein. They have proposed a temporal sequence in which the appearance of Lewy bodies and neurites in brainstem structures represent the earliest manifestations of the disease, and that this involvement of non-dopaminergic structures long antedates involvement of the substantia nigra and the appearance of the cardinal motor signs that are now required for diagnosis. This proposed scheme has had a wide and profound impact on many aspects of current thinking about PD, and it has already received wide acceptance. Given the importance and growing acceptance of the Braak staging scheme, the Scientific Program Committee for this Educational Symposium to honor the 50th Anniversary of the Parkinson's Disease Foundation agreed that it would be highly worthwhile to devote an entire session of the Scientific Program to consideration of the Braak staging scheme. There was a consensus among members of the Committee that, given the importance of the Braak scheme, it would be of value to create a venue that would stimulate and encourage a thorough and incisive critical analysis.

Topics: alpha-Synuclein; Evaluation Studies as Topic; Humans; Parkinsonian Disorders; Severity of Illness Index

The E46K is a point mutation in alpha-synuclein (alpha-syn) that causes familial Parkinsonism with Lewy body dementia. We have now generated a cell model of Parkinsonism/Parkinson's disease (PD) and demonstrated cell toxicity after expression of E46K in the differentiated PC12 cells. E46K alpha-syn inhibited proteasome activity and induced mitochondrial depolarization in the cell model. Baicalein has been reported to inhibit fibrillation of wild type alpha-syn in vitro, and to protect neurons against several chemical-induced models of PD. We now report that baicalein significantly attenuated E46K-induced mitochondrial depolarization and proteasome inhibition, and protected cells against E46K-induced toxicity in a cell model of PD. Baicalein also reduced E46K fibrilization in vitro, with a concentration-dependent decrease in beta sheet conformation, though it increased some oligomeric species, and decreased formation of E46K alpha-syn-induced aggregates and rescued toxicity in N2A cells. Taken together, these data indicate that mitochondrial dysfunction, proteasome inhibition and specific aspects of abnormal E46K aggregation accompany E46K alpha-syn-induced cell toxicity, and baicalein can protect as well as altering aggregation properties. Baicalein has potential as a tool to understand the relation between different aggregation species and toxicity, and might be a candidate compound for further validation by using in vivo alpha-syn genetic PD models.

Topics: alpha-Synuclein; Animals; Cell Death; Cell Differentiation; Flavanones; Membrane Potential, Mitochondrial; Mutation; Neurons; Parkinsonian Disorders; PC12 Cells; Proteasome Inhibitors; Rats

Parkinson's disease (PD) is a severe neurodegenerative disorder characterised by loss of dopaminergic neurons of the substantia nigra. The pathological hallmarks are cytoplasmic inclusions termed Lewy bodies consisting primarily of aggregated alpha-synuclein (alphaSN). Different lines of transgenic mice have been developed to model PD but have failed to recapitulate the hallmarks of this disease. Since treatment of rodents with the pesticide rotenone can reproduce nigrostriatal cell loss and other features of PD, we aimed to test chronic oral administration of rotenone to transgenic mice over-expressing human alphaSN with the A53T mutation. Initial assessment of this transgenic line for compensatory molecular changes indicated decreased brain beta-synuclein expression and significantly increased levels of the PD-associated oxidative stress response protein, DJ-1, and the E3 ubiquitin ligase enzyme, Parkin. Rotenone treatment of 30 mg/kg for 25 doses over a 35-day period was tolerated in the transgenic mice and resulted in decreased spontaneous locomotor movement and increased cytoplasmic alphaSN expression. The mitochondrial Parkinson's-associated PTEN-induced kinase 1 protein levels were also increased in transgenic mouse brain after rotenone treatment; there was no change in brain dopamine levels or nigrostriatal cell loss. These hA53T alphaSN transgenic mice provide a useful model for presymptomatic Parkinson's features and are valuable for study of associated compensatory changes in early Parkinson's disease stages.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Oncogene Proteins; Parkinsonian Disorders; Peroxiredoxins; Protein Deglycase DJ-1; Protein Kinases; Rotenone; Ubiquitin-Protein Ligases; Uncoupling Agents; Up-Regulation

Gastrointestinal (GI) dysfunction occurs frequently in early Parkinson's disease (PD) and it is supposed to anticipate motor symptoms. About 80% of PD patients suffer from constipation before the onset of movement disorders. Despite such a high prevalence of gut impairment in PD, the molecular mechanisms remain poorly investigated. This is also due to the scarcity of experimental studies. In the present work, we tried to reproduce digestive abnormalities observed in PD patients by administering the parkinsonism-inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP) to C57BL mice. We show that in these mice, MPTP (20mg/kg × 3) while producing the classic striatal dopamine (DA) denervation, persistently delays colonic motility, produces constipation, and reduces the number of enteric TH-positive neurons. The loss of TH-positive cells in the gut is selectively due to the disappearance of DA neurons within both myenteric and mostly submucosal plexus in the intestine, while no change is detected in the esophagus and stomach. In contrast, norepinephrine (NE) neurons are not affected. These data were confirmed by immunohistochemistry and by HPLC showing the significant loss of DA levels while NE and 5-HT content was not affected. Dopamine cell loss was associated with increased α-synuclein levels. These functional, biochemical, and morphological findings extend the PD-mimicking effects of MPTP to GI dysfunctions and provide a useful experimental model to understand gut dysfunction in PD and to find effective treatments for digestive symptoms.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Enteric Nervous System; Gastrointestinal Diseases; Gastrointestinal Motility; Male; Mice; Mice, Inbred C57BL; Neural Pathways; Neurons; Parkinsonian Disorders; Random Allocation; Substantia Nigra; Tyrosine 3-Monooxygenase

Over the last years, a plethora of genetic findings have completely changed our views on the aetiology of Parkinson's disease (PD). Linkage studies and positional cloning strategies have identified mutations in a growing number of genes which cause monogenic autosomal-dominant or autosomal-recessive forms of the disorder. While these Mendelian forms of PD are relatively rare, high-throughput genotyping and sequencing technologies have more recently provided evidence that low-penetrance variants in at least some of these genes also play a direct role in the aetiology of the common sporadic disease. In addition, rare variants in other genes, such as the Gaucher's disease-associated glucocerebrosidase A, have also been found to be important risk factors at least in subgroups of patients. Thus, an increasingly complex network of genes contributing in different ways to disease risk and progression is emerging. These findings provide the 'genetic entry points' to identify molecular targets and readouts necessary to design rational disease-modifying treatments.

Topics: alpha-Synuclein; Genetic Predisposition to Disease; Genome-Wide Association Study; Glucosylceramidase; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Molecular Sequence Data; Mutation; Oncogene Proteins; Parkinsonian Disorders; Polymorphism, Single Nucleotide; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; tau Proteins; Ubiquitin-Protein Ligases

In Parkinson's disease (PD) patients, the associated pathology follows a characteristic pattern involving inter alia the enteric nervous system (ENS) (1,2), the olfactory bulb (OB), the dorsal motor nucleus of the vagus (DMV)(3), the intermediolateral nucleus of the spinal cord (4) and the substantia nigra, providing the basis for the neuropathological staging of the disease(4,5). The ENS and the OB are the most exposed nervous structures and the first ones to be affected. Interestingly, PD has been related to pesticide exposure(6-8). Here we show in detail two methods used in our previous study (9). In order to analyze the effects of rotenone acting locally on the ENS, we administered rotenone using a gavage to one-year old C57/BL6 mice. Rotenone is a widely used pesticide that strongly inhibits mitochondrial Complex I (10). It is highly lipophylic and poorly absorbed in the gastrointestinal tract (11). Our results showed that the administration of 5 mg/kg of rotenone did not inhibit mitochondrial Complex I activity in the muscle or the brain. Thus, suggesting that using our administration method rotenone did not cross the hepatoportal system and was acting solely on the ENS. Here we show a method to administer pesticides using a gavage and the image analysis protocol used to analyze the effects of the pesticide in alpha-synuclein accumulation in the ENS. The first part shows a method that allows intragastric administration of pesticides (rotenone) at a desired precise concentration. The second method shows a semi-automatic image analysis protocol to analyze alpha-synuclein accumulation in the ENS using an image analysis software.

Topics: Administration, Oral; alpha-Synuclein; Animals; Disease Models, Animal; Enteric Nervous System; Image Processing, Computer-Assisted; Intubation, Gastrointestinal; Mice; Mice, Inbred C57BL; Microscopy, Confocal; Parkinsonian Disorders; Rotenone

Lewy bodies in Parkinson disease could be innocent bystanders or active agents responsible for neuronal death. Eighteen elderly patients with a Parkinson syndrome were studied prospectively and selected postmortem on the presence of Lewy bodies (14 cases with Parkinson disease, four with dementia with Lewy bodies). Information on disease duration was available in 17 cases. While akinesia and rigidity were linked with the neuronal loss, the percentages of Lewy body bearing neurons and of alpha-synuclein immunoreactive neurons in the substantia nigra were not correlated with the symptoms or the disease duration, and appeared stable, involving 3.6% of the neurons on average. Such stability indicated that, during the whole course of the disease, the destruction of the Lewy bodies was equal to their production. In the model that is proposed here, the Lewy bodies are eliminated when the neurons that bear them die. With the hypothesis that neuronal death is directly related to Lewy bodies, it is possible to estimate their life span, which was calculated to be 6.2 months (15.9 months for any type of alpha-synuclein inclusion).

Topics: Age of Onset; alpha-Synuclein; Cell Count; Cell Death; Disease Progression; Humans; Lewy Bodies; Lewy Body Disease; Nerve Degeneration; Neurons; Parkinson Disease; Parkinsonian Disorders; Prospective Studies; Substantia Nigra; Time Factors

DnaJ/Hsp40 chaperones determine the activity of Hsp70s by stabilizing their interaction with substrate proteins. We have predicted, based on the in silico analysis of a brain-derived whole-genome transcriptome data set, an increased expression of DnaJ/Hsp40 homologue, subfamily B, member 6 (DnaJB6) in Parkinson's disease (PD; Moran et al. [2006] Neurogenetics 7:1-11). We now show that DnaJB6 is a novel component of Lewy bodies (LBs) in both PD substantia nigra and PD cortex and that it is strongly up-regulated in parkinsonian astrocytes. The presence of DnaJB6 in the center of LBs suggests an early and direct involvement of this chaperone in the neuronal disease process associated with PD. The strong concomitant expression of DnaJB6 in astrocytes emphasizes the involvement of glial cells in PD and could indicate a route for therapeutic intervention. Extracellular alpha-synuclein originating from intravesicular alpha-synuclein is prone to aggregation and the potential source of extracellular aggregates (Lee [2008] J. Mol. Neurosci. 34:17-22). The observed strong expression of DnaJB6 by astrocytes could reflect a protective reaction, so reducing the neuronal release of toxic alpha-synuclein and supporting the astrocyte response in PD might limit the progression of the disease process.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Astrocytes; Female; HSP40 Heat-Shock Proteins; Humans; Lewy Bodies; Male; Molecular Chaperones; Nerve Tissue Proteins; Parkinsonian Disorders; Postmortem Changes; RNA, Messenger; Up-Regulation

Early onset Parkinson's disease (EOPD) has been associated with mutations in the Parkin, DJ-1, PINK1, LRRK2, and SNCA genes. The aim of this study is to assess the contribution of these genes in a Dutch EOPD cohort and the phenotypic characteristics of the mutation carriers. A total of 187 unrelated Dutch EOPD patients (age at onset < or = 50 years) were phenotyped and screened for mutations in all exons of Parkin, DJ-1, and PINK1 by direct sequencing and gene dosage analysis. Additionally, analysis of the A30P mutation and exon dosage of SNCA and sequencing of exons 19,31,35,38,41, and 48 of LRRK2 was performed. Pathogenic variations could explain disease in 4% (7 of 187) of the patients including five patients carrying homozygous or compound heterozygous mutations in Parkin, one with a novel homozygous deletion in DJ-1 (P158Del) and one with a heterozygous mutation in LRRK2 (T2356I). We found seven novel mutations. The phenotypic characteristics of mutation carriers varied widely, comparable to the variability seen in sporadic EOPD. Parkin is the most frequently mutated gene in this EOPD cohort, followed by DJ-1, PINK1 and LRRK2. The low overall mutation frequency indicates that the extrapolation of mutation frequencies from other populations should be applied with caution.

Topics: Adolescent; Adult; Age of Onset; alpha-Synuclein; Amino Acid Sequence; Conserved Sequence; DNA Mutational Analysis; Female; Genotype; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Molecular Sequence Data; Netherlands; Oncogene Proteins; Parkinson Disease; Parkinsonian Disorders; Phenotype; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Sequence Alignment; Sequence Homology, Nucleic Acid; Ubiquitin-Protein Ligases; Young Adult

Mutations in LRRK2 are the single most common known cause of Parkinson's disease (PD). Two new PD patients with LRRK2 mutation were identified from a cohort with extensive postmortem assessment. One of these patients harbors the R793M mutation and presented with the typical clinical and pathological features of PD. A novel L1165P mutation was identified in a second patient. This patient had the classical and pathological features of PD, but additionally developed severe neuropsychological symptoms and dementia associated with abundant neurofibrillary tangles in the hippocampal formation; features consistent with a secondary diagnosis of tangle-predominant dementia. alpha-Synuclein-containing pathological inclusions in these patients also were highly phosphorylated at Ser-129, similar to other patients with idiopathic PD. These two PD patients also were characterized by the presence of occasional cytoplasmic TDP-43 inclusions in the temporal cortex, a finding that was not observed in three other patients with the G2019S mutation in LRRK2. These findings extend the clinical and pathological features that may be associated with LRRK2 mutations.

Topics: Aged; alpha-Synuclein; Amino Acid Sequence; Cohort Studies; DNA Mutational Analysis; Female; Genes, Dominant; Hippocampus; Humans; Inclusion Bodies; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Molecular Sequence Data; Mutation, Missense; Neurofibrillary Tangles; Parkinson Disease; Parkinsonian Disorders; Phosphorylation; Phosphoserine; Point Mutation; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Sequence Alignment; Sequence Homology, Amino Acid; Temporal Lobe

Recently, the aldehyde 4-oxo-2-nonenal (ONE) was identified as a product of lipid peroxidation and found to be an effective protein modifier. In this in vitro study we investigated structural implications of the interaction between ONE and alpha-synuclein, a protein which forms intraneuronal inclusions in neurodegenerative disorders such as Parkinson's disease and dementia with Lewy bodies. Our results demonstrate that ONE induced an almost complete conversion of monomeric alpha-synuclein into 40-80 nm wide and 6-8 nm high soluble beta-sheet-rich oligomers with a molecular weight of approximately 2000 kDa. Furthermore, the ONE-induced alpha-synuclein oligomers displayed a high stability and were not sensitive to treatment with sodium dodecyl sulfate, indicating that ONE stabilized the oligomers by cross-linking individual alpha-synuclein molecules. Despite prolonged incubation the oligomers did not continue to aggregate into a fibrillar state, thus suggesting that these alpha-synuclein species were not on a fibrillogenic pathway.

Topics: Aldehydes; alpha-Synuclein; Amyloid; Chromatography, High Pressure Liquid; Humans; Lipid Peroxidation; Microscopy, Atomic Force; Molecular Weight; Parkinsonian Disorders; Protein Conformation; Sodium Dodecyl Sulfate

Both genetic and environmental factors are thought to be involved in the aetiology of Parkinson's disease (PD). Oxidative damage, mitochondrial and proteasomal dysfunction, and inflammatory change are considered to participate in PD pathogenesis. Dopamine agonists are used in the symptomatic treatment of PD but attention has recently also been focussed on their potential for use in slowing disease progression. We have studied the protective actions of the D2 dopamine agonist cabergoline in toxin (paraquat) and genetic (wild-type and mutant [A53T] alpha-synuclein) models of PD using SHSY-5Y cells. Cabergoline increased glutathione content, reduced free radical production and caspase-3 activation, increased mitochondrial membrane potential and ameliorated cell death in SHSY-5Y cells exposed to paraquat and this action was inhibited in part by D2 receptor blockade. Cabergoline also reduced the toxicity of wild-type and mutant alpha-synuclein expression following paraquat exposure by similar mechanisms. These results confirm the protective action of cabergoline in reducing cell death in two separate genetic and environmental model systems of PD.

Topics: alpha-Synuclein; Analysis of Variance; Apoptosis; Blotting, Western; Cabergoline; Caspase 3; Cell Line; Enzyme Activation; Ergolines; Glutathione; Humans; Immunohistochemistry; JNK Mitogen-Activated Protein Kinases; Lactate Dehydrogenases; Membrane Potential, Mitochondrial; Paraquat; Parkinsonian Disorders; Reactive Oxygen Species; Receptors, Dopamine D2

Neuroinflammation, characterized by activated microglia and infiltrating T cells, is a prominent pathological feature in neurodegenerative diseases. However, whether this inflammation contributes to neuronal injury or is a late consequence of neuronal injury is unclear. In this issue of the JCI, Brochard et al. report that CD4+ T cells are cytotoxic in a mouse model of Parkinson disease (PD) (see the related article beginning on page 182). Specifically, invading T lymphocytes contributed to neuronal cell death via the Fas/FasL pathway. The results implicate the adaptive immune system in the pathogenesis of Parkinson neurodegeneration and provide a meaningful rationale for immune-based therapies for PD.

Topics: alpha-Synuclein; Animals; Apoptosis; CD4-Positive T-Lymphocytes; Cytotoxicity, Immunologic; Disease Models, Animal; Dopamine; Humans; Inflammation; Mice; Microglia; Parkinsonian Disorders; T-Lymphocyte Subsets

Alpha-synuclein remains a protein of interest due to its propensity to form fibrillar aggregates in neurodegenerative disease and its putative function in synaptic vesicle regulation. Herein, we present a series of atomistic molecular dynamics simulations of wild-type alpha-synuclein and three Parkinson disease familial mutants (A30P, A53T, and E46K) in two distinct environments. First, in order to match recent NMR experiments, we have simulated each protein bound to an SDS detergent micelle. Second, in order to connect more closely to the true biological environment, we have simulated the proteins bound to a 1,2-dioleoyl-sn-glycero-3-phosphoserine lipid bilayer. In the micelle-bound case, we find that the wild type and all of the variants of alpha-synuclein flatten the underlying micelle, decreasing its surface area. A30P is known to lessen alpha-synuclein/membrane affinity and, consistent with experiment, destabilizes the simulated secondary structure. In the case of A53T, our simulations reveal a range of stabilizing hydrogen bonds that form with the threonine. In both environments, the E46K mutation, which is known to increase bilayer affinity, leads to an additional hydrogen bond between the protein and either the detergent or lipid. Simulations indicate that alphaS and its variants are less dynamic in the bilayer than in the micelle. Furthermore, the simulations of the mutants suggest how changes in the structure and dynamics of alpha-synuclein may affect its biological role.

Topics: alpha-Synuclein; Amino Acid Substitution; Computer Simulation; Humans; Lipid Bilayers; Micelles; Models, Molecular; Mutation, Missense; Parkinsonian Disorders; Protein Structure, Secondary; Sodium Dodecyl Sulfate; Structure-Activity Relationship

Genomic multiplications of the alpha-synuclein gene (SNCA) cause autosomal dominant Parkinson disease (ADPD). The aim of this study was to assess the frequency and phenotype of SNCA rearrangements in a large series of families with typical or atypical AD parkinsonism.. Patients were screened by the exon dosage of the SNCA gene. The genotype of patients and relatives carrying SNCA rearrangements, the size of the multiplied regions, and the centromeric and telomeric breakpoints were determined by microsatellite dosage and 250K Affymetrix Single Polymorphism Nucleotide microarrays (Affymetrix, Santa Clara, California).. Index cases and, whenever appropriate, relatives of 286 mainly European families with ADPD were screened.. Four of 264 families (1.5%) with typical ADPD carried duplications and 1 of 22 families (4.5%) with atypical AD parkinsonism carried a triplication of SNCA. Genotyping and dosage analyses showed that the multiplied regions were variable in size (0.42-5.29 megabase pairs), suggesting that SNCA multiplications occurred independently. Phenotype analyses showed that the severity of the disease correlated with the SNCA copy number, but not with the minimal number of multiplied genes (1 to 33). Haplotype analysis of polymorphic markers suggested that multiplication of the SNCA gene occurred by both interchromosomal and intrachromosomal rearrangement.. Our results suggest that SNCA rearrangements may be more frequent than point mutations in ADPD. Furthermore, our results indicate that the phenotype associated with SNCA multiplications correlates with the number of copies of the gene and provides the first insight into the mechanisms underlying SNCA multiplication.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Brain Chemistry; Chromosome Breakage; DNA Mutational Analysis; DNA Repeat Expansion; Female; Gene Dosage; Genes, Dominant; Genetic Predisposition to Disease; Genetic Testing; Genotype; Haplotypes; Humans; Male; Microsatellite Repeats; Middle Aged; Oligonucleotide Array Sequence Analysis; Parkinsonian Disorders; Polymorphism, Single Nucleotide

Topics: alpha-Synuclein; Blotting, Southern; Brain; DNA Mutational Analysis; DNA Polymerase gamma; DNA-Directed DNA Polymerase; DNA, Mitochondrial; Electron Transport Complex IV; Humans; Immunohistochemistry; Lewy Bodies; Male; Middle Aged; Muscle, Skeletal; Mutation; Myelin Sheath; Parkinsonian Disorders; Polymerase Chain Reaction; Spinal Cord; Voltage-Dependent Anion Channels

Topics: alpha-Synuclein; Amino Acids, Diamino; Amyotrophic Lateral Sclerosis; Animals; Bacterial Toxins; Causality; Cyanobacteria Toxins; Cycas; Dementia; Disease Models, Animal; Epidemiologic Research Design; Epidemiologic Studies; Flour; Guam; Hazardous Substances; Humans; Incidence; Indonesia; Japan; Marine Toxins; Methylazoxymethanol Acetate; Microcystins; Nerve Degeneration; Parkinsonian Disorders; Plant Extracts; Syndrome; Tauopathies

The aim of the study was to evaluate the frequency and to perform phenotypic and genotypic characterization of familial Parkinsonism and early onset Parkinson's disease (EOPD) in a Brazilian movement disorder unit. We performed a standardized clinical assessment of patients followed by sequencing of PRKN, PINK1 in EOPD cases and SNCA, LRRK2 in familial Parkinsonism individuals. During the period of study (January through December, 2006), we examined 575 consecutive patients of whom 226 (39.3%) met the diagnosis of Parkinsonism and idiopathic Parkinson's disease (IPD) was diagnosed in 202 of the latter. Of the IPD cases, 45 (22.3%) had EOPD. The age at onset in the EOPD cases (n = 45) was 34.8 +/- 5.4 years (mean +/- standard deviation). The age at onset in the familial late-onset PD patients (n = 8) was 52.3 +/- 12.2 years. In the early onset cases, we identified five known mutations in PRKN, two single heterozygous and three compound heterozygous (P153R, T240M, 255Adel, W54R, V3I); in addition, we identified one novel mutation in PINK1 (homozygous deletion of exon 7). In the familial cases (late onset), 1 patient had a novel LRRK2 variant, Q923H, but no SNCA mutations were identified. We have demonstrated that EOPD accounts for a high frequency of IPD cases in our tertiary referral center. PRKN was the most commonly mutated gene, but we also identified a novel mutation in PINK1 and a novel variant in LRRK2.

Topics: Adult; Age of Onset; Aged; alpha-Synuclein; Amino Acids; Brazil; DNA Mutational Analysis; Female; Genetic Predisposition to Disease; Genotype; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Molecular Sequence Data; Mutation; Parkinson Disease; Parkinsonian Disorders; Phenotype; Protein Kinases; Protein Serine-Threonine Kinases; Ubiquitin-Protein Ligases

Recent whole genome association studies provided little evidence that polymorphisms at the familial Parkinsonism loci influence the risk for Parkinson's disease (PD). However, these studies are not designed to detect the types of subtle effects that common variants may impose. Here, we use an alternative targeted candidate gene approach to examine common variation in 11 genes related to familial Parkinsonism. PD cases (n = 331) and unaffected control subjects (n = 296) were recruited from three specialist movement disorder clinics in Brisbane, Australia and the Australian Electoral Roll. Common genetic variables (76 SNPs and 1 STR) were assessed in all subjects and haplotype, genotype, and allele associations explored. Modest associations (uncorrected P < 0.05) were observed for common variants around SNCA, UCHL1, MAPT, and LRRK2 although none were of sufficient magnitude to survive strict statistical corrections for multiple comparisons. No associations were seen for PRKN, PINK1, GBA, ATP13A2, HTRA2, NR4A2, and DJ1. Our findings suggest that common genetic variables of selected PD-related loci contribute modestly to PD risk in Australians.

Topics: Aged; alpha-Synuclein; Australia; Female; Gene Frequency; Genetic Predisposition to Disease; Genome-Wide Association Study; Genotype; Glucosylceramidase; High-Temperature Requirement A Serine Peptidase 2; Humans; Intracellular Signaling Peptides and Proteins; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Mitochondrial Proteins; Oncogene Proteins; Parkinson Disease; Parkinsonian Disorders; Polymorphism, Genetic; Protein Deglycase DJ-1; Protein Kinases; Protein Serine-Threonine Kinases; Proton-Translocating ATPases; Retrospective Studies; Serine Endopeptidases; tau Proteins; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases

Soluble oligomeric aggregates of alpha-synuclein have been implicated to play a central role in the pathogenesis of Parkinson's disease. Disruption and permeabilization of lipid bilayers by alpha-synuclein oligomers is postulated as a toxic mechanism, but the molecular details controlling the oligomer-membrane interaction are still unknown. Here we show that membrane disruption strongly depends on the accessibility of the hydrophobic membrane core and that charge interactions play an important but complex role. We systematically studied the influence of the physical membrane properties and solution conditions on lipid bilayer disruption by oligomers using a dye release assay. Varying the lipid headgroup composition revealed that membrane disruption only occurs for negatively charged bilayers. Furthermore, the electrostatic repulsion between the negatively charged alpha-synuclein and the negative surface charge of the bilayer inhibits vesicle disruption at low ionic strength. The disruption of negatively charged vesicles further depends on lipid packing parameters. Bilayer composition changes that result in an increased lipid headgroup spacing make vesicles more prone to disruption, suggesting that the accessibility of the bilayer hydrocarbon core modulates oligomer-membrane interaction. These data shed important new insights into the driving forces governing the highly debated process of oligomer-membrane interactions.

Topics: alpha-Synuclein; Amino Acid Substitution; Cell Death; Electrophoresis, Polyacrylamide Gel; Humans; Kinetics; Lipid Bilayers; Parkinsonian Disorders; Phosphatidylglycerols; Spectrophotometry, Ultraviolet; Substantia Nigra

The systemic rotenone model of Parkinson's disease (PD) accurately replicates many aspects of the pathology of human PD and has provided insights into the pathogenesis of PD. The major limitation of the rotenone model has been its variability, both in terms of the percentage of animals that develop a clear-cut nigrostriatal lesion and the extent of that lesion. The goal here was to develop an improved and highly reproducible rotenone model of PD. In these studies, male Lewis rats in three age groups (3, 7 or 12-14 months) were administered rotenone (2.75 or 3.0 mg/kg/day) in a specialized vehicle by daily intraperitoneal injection. All rotenone-treated animals developed bradykinesia, postural instability, and/or rigidity, which were reversed by apomorphine, consistent with a lesion of the nigrostriatal dopamine system. Animals were sacrificed when the PD phenotype became debilitating. Rotenone treatment caused a 45% loss of tyrosine hydroxylase-positive substantia nigra neurons and a commensurate loss of striatal dopamine. Additionally, in rotenone-treated animals, alpha-synuclein and poly-ubiquitin positive aggregates were observed in dopamine neurons of the substantia nigra. In summary, this version of the rotenone model is highly reproducible and may provide an excellent tool to test new neuroprotective strategies.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopamine; Dyskinesia, Drug-Induced; Hypokinesia; Injections, Intraperitoneal; Male; Muscle Rigidity; Nerve Degeneration; Neurons; Neurotoxins; Parkinsonian Disorders; Rats; Rats, Inbred Lew; Reproducibility of Results; Rotenone; Substantia Nigra; Tyrosine 3-Monooxygenase; Ubiquitins; Uncoupling Agents

Sporadic Parkinson's disease (PD) is a progressive neurodegenerative disorder with unknown cause, but it has been suggested that neuroinflammation may play a role in pathogenesis of the disease. Neuroinflammatory component in process of PD neurodegeneration was proposed by postmortem, epidemiological and animal model studies. However, it remains unclear how neuroinflammatory factors contribute to dopaminergic neuronal death in PD.. In this study, we analyzed the relationship among inducible nitric oxide synthase (iNOS)-derived NO, mitochondrial dysfunction and dopaminergic neurodegeneration to examine the possibility that microglial neuroinflammation may induce dopaminergic neuronal loss in the substantia nigra. Unilateral injection of lipopolysaccharide (LPS) into the striatum of rat was followed by immunocytochemical, histological, neurochemical and biochemical analyses. In addition, behavioral assessments including cylinder test and amphetamine-induced rotational behavior test were employed to validate ipsilateral damage to the dopamine nigrostriatal pathway. LPS injection caused progressive degeneration of the dopamine nigrostriatal system, which was accompanied by motor impairments including asymmetric usage of forelimbs and amphetamine-induced turning behavior in animals. Interestingly, some of the remaining nigral dopaminergic neurons had intracytoplasmic accumulation of alpha-synuclein and ubiquitin. Furthermore, defect in the mitochondrial respiratory chain, and extensive S-nitrosylation/nitration of mitochondrial complex I were detected prior to the dopaminergic neuronal loss. The mitochondrial injury was prevented by treatment with L-N(6)-(l-iminoethyl)-lysine, an iNOS inhibitor, suggesting that iNOS-derived NO is associated with the mitochondrial impairment.. These results implicate neuroinflammation-induced S-nitrosylation/nitration of mitochondrial complex I in mitochondrial malfunction and subsequent degeneration of the nigral dopamine neurons.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Cytoplasm; Disease Progression; Dopamine; Drug Administration Routes; Electron Transport Complex I; Inflammation; Lipopolysaccharides; Male; Mitochondria; Neostriatum; Nerve Degeneration; Neurons; Nitrosation; Parkinsonian Disorders; Rats; Rats, Sprague-Dawley; Ubiquitin

Fifty-two patients that had ParkinsonTs disease with autosomal dominant type of inheritance were analyzed for the presence of duplications and triplications in exons 4--6 of alpha-synuclein gene using real-time PCR with Taq-Man probes. No mutations involving the examined exons dosage were revealed in alpha-synuclein gene. Thus, mutations modifying copy number of alpha-synuclein gene do not significantly affect the pathogenesis of the autosomal dominant form of ParkinsonTs disease in patients from Russia.

Topics: alpha-Synuclein; Exons; Female; Gene Dosage; Humans; Male; Parkinsonian Disorders; Reverse Transcriptase Polymerase Chain Reaction; Russia

Parkinsonism, chorea, and dystonia are well-known clinical manifestations of Creutzfeldt-Jakob disease (CJD), but lesions of the nigrostriatal pathway have never been thoroughly studied. We performed a detailed neuropathologic study of the nigrostriatal pathway in 15 sporadic CJD and 2 variant CJD cases that included clinical correlations and assessment of neuron subtype loss, distribution of prion protein, alpha-synuclein, ubiquitin, and 14-3-3 aggregation. We found evidence of nigrostriatal pathway damage in these CJD cases. Dopaminergic neurons and striatal outflow neurons were markedly affected in sporadic CJD, whereas cholinergic interneurons were spared. In cases of CJD with chorea or myoclonus, there was less presynaptic dopaminergic loss than in cases of CJD with parkinsonism. The 2 variant CJD cases with parkinsonism or chorea showed severe cholinergic interneuron loss in the caudate and putamen, a pattern that differed from that found in sporadic CJD. alpha-Synuclein, ubiquitin, and 14-3-3 aggregation coexisted with prion protein aggregation, thereby generating mixed pathological features. These findings suggest a possible pathophysiological overlap of abnormal protein aggregation in CJD and Parkinson disease.

Topics: 14-3-3 Proteins; Adult; Aged; Aged, 80 and over; alpha-Synuclein; Chorea; Corpus Striatum; Creutzfeldt-Jakob Syndrome; Female; Humans; Male; Middle Aged; Myoclonus; Neural Pathways; Neurons; Parkinsonian Disorders; Prions; Substantia Nigra; Ubiquitin; Young Adult

Phage display has demonstrated the utility of cyclic peptides as general protein ligands but cannot access proteins inside eukaryotic cells. Expanding a new chemical genetics tool, we describe the first expressed library of head-to-tail cyclic peptides in yeast (Saccharomyces cerevisiae). We applied the library to selections in a yeast model of alpha-synuclein toxicity that recapitulates much of the cellular pathology of Parkinson's disease. From a pool of 5 million transformants, we isolated two related cyclic peptide constructs that specifically reduced the toxicity of human alpha-synuclein. These expressed cyclic peptide constructs also prevented dopaminergic neuron loss in an established Caenorhabditis elegans Parkinson's model. This work highlights the speed and efficiency of using libraries of expressed cyclic peptides for forward chemical genetics in cellular models of human disease.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Humans; Neurons; Parkinsonian Disorders; Peptide Library; Peptides, Cyclic; Point Mutation; Promoter Regions, Genetic; Protein Folding; Saccharomyces cerevisiae; Structure-Activity Relationship

Chronic neuroinflammation is implicated in Parkinson's disease (PD). Inflammation involves the activation of microglia and astrocytes that release high levels of prostaglandins. There is a profound gap in our understanding of how cyclooxygenases and their prostaglandin products redirect cellular events to promote PD neurodegeneration. The major prostaglandin in the mammalian brain is prostaglandin D2, which readily undergoes spontaneous dehydration to generate the bioactive cyclopentenone prostaglandins of the J2 series. These J2 prostaglandins are highly reactive and neurotoxic products of inflammation shown in cellular models to impair the ubiquitin/proteasome pathway and cause the accumulation of ubiquitinated proteins. PD is a disorder that exhibits accumulation of ubiquitinated proteins in neuronal inclusions (Lewy bodies). The role of J2 prostaglandins in promoting PD neurodegeneration has not been investigated under in vivo conditions.. We addressed the neurodegenerative and behavioral effects of the administration of prostaglandin J2 (PGJ2) simultaneously into the substantia nigra/striatum of adult male FVB mice by subchronic microinjections. One group received unilateral injections of DMSO (vehicle, n = 6) and three groups received PGJ2 [3.4 microg or 6.7 microg (n = 6 per group) or 16.7 microg (n = 5)] per injection. Immunohistochemical and behavioral analyses were applied to assess the effects of the subchronic PGJ2 microinfusions.. Immunohistochemical analysis demonstrated a PGJ2 dose-dependent significant and selective loss of dopaminergic neurons in the substantia nigra while the GABAergic neurons were spared. PGJ2 also triggered formation of aggregates immunoreactive for ubiquitin and alpha-synuclein in the spared dopaminergic neurons. Moreover, PGJ2 infusion caused a massive microglia and astrocyte activation that could initiate a deleterious cascade leading to self-sustained progressive neurodegeneration. The PGJ2-treated mice also exhibited locomotor and posture impairment.. Our studies establish the first model of inflammation in which administration of an endogenous highly reactive product of inflammation, PGJ2, recapitulates key aspects of PD. Our novel PGJ2-induced PD model strongly supports the view that localized and chronic production of highly reactive and neurotoxic prostaglandins, such as PGJ2, in the CNS could be an integral component of inflammation triggered by insults evoked by physical, chemical or microbial stimuli and thus establishes a link between neuroinflammation and PD neurodegeneration.

Topics: alpha-Synuclein; Animals; Cell Death; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Drug Administration Schedule; Encephalitis; Gliosis; Immunohistochemistry; Inclusion Bodies; Inflammation Mediators; Male; Mice; Microinjections; Movement Disorders; Nerve Degeneration; Neurons; Parkinsonian Disorders; Prostaglandin D2; Substantia Nigra

Pramipexole, an agonist for dopamine (DA) D2/D3-receptors, has been used to treat both early and advanced Parkinson's disease (PD). In this study, we examined the effect of pramipexole on DA neurons in a PD model of C57BL/6 mice, which were treated with rotenone (30 mg/kg, p.o.) daily for 28 days. Pramipexole (1 mg/kg, i.p.) was injected daily 30 min before each oral administration of rotenone. Chronic oral administration of rotenone caused a loss of DA neurons in the substantia nigra pars compacta (SNpc), motor deficits and the up-regulation of alpha-synuclein immunoreactivity in some surviving DA neurons. Pramipexole inhibited rotenone-induced DA neuronal death and motor deficits, and reduced immunoreactivity for alpha-synuclein. In addition, pramipexole inhibited the in vitro oligomerization of human wild-type alpha-synuclein by H(2)O(2)plus cytochrome c. To examine the neuroprotective effect of pramipexole against oxidative stress, we used a DJ-1-knockdown SH-SY5Y cell line and electron spin resonance (ESR) spectrometry. Simultaneous treatment with H(2)O(2) and pramipexole resulted in the significant protection of DJ-1-knockdown cells against cell death in a concentration-dependent manner. A high concentration of pramipexole directly scavenged hydroxyl radical (*OH) generated from H(2)O(2) and Fe(2+). Furthermore, pramipexole increased Bcl-2 immunoreactivity in DA neurons in the SNpc. These results suggest that pramipexole may protect DA neurons against exposure to rotenone by chronic oral administration, and this effect is mediated by multiple functions including scavenging of *OH and induction of Bcl-2 protein.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Apoptosis; Benzothiazoles; Cell Line, Tumor; Corpus Striatum; Cytochromes c; Dopamine; Dose-Response Relationship, Drug; Humans; Hydrogen Peroxide; Hydroxyl Radical; Male; Mice; Mice, Inbred C57BL; Nerve Degeneration; Neural Pathways; Neurotoxins; Oxidative Stress; Parkinsonian Disorders; Pramipexole; Proto-Oncogene Proteins c-bcl-2; Rotenone; Substantia Nigra; Uncoupling Agents

Topics: Adult; Age of Onset; Aging; AIDS Dementia Complex; alpha-Synuclein; Antiretroviral Therapy, Highly Active; Causality; Disease Progression; Humans; Male; Middle Aged; Mitochondrial Diseases; Nerve Degeneration; Neurons; Parkinsonian Disorders; RNA, Viral; Substantia Nigra; Ubiquitination; Viral Load

Parkinson disease (PD) is the second most common neurodegenerative disorder in the United States. It is associated with motor deficits, sleep disturbances, and cognitive impairment. The pathology associated with PD and the effects of sleep deprivation impinge, in part, upon common molecular pathways suggesting that sleep loss may be particularly deleterious to the degenerating brain. Thus we investigated the long-term consequences of sleep deprivation on shortterm memory using a Drosophila model of Parkinson disease.. Transgenic strains of Drosophila melanogaster.. Using the GAL4-UAS system, human alpha-synuclein was expressed throughout the nervous system of adult flies. Alpha-synuclein expressing flies (alpha S flies) and the corresponding genetic background controls were sleep deprived for 12 h at age 16 days and allowed to recover undisturbed for at least 3 days. Short-term memory was evaluated using aversive phototaxis suppression. Dopaminergic systems were assessed using mRNA profiling and immunohistochemistry. MEASURMENTS AND RESULTS: When sleep deprived at an intermediate stage of the pathology, alpha S flies showed persistent short-term memory deficits that lasted > or = 3 days. Cognitive deficits were not observed in younger alpha S flies nor in genetic background controls. Long-term impairments were not associated with accelerated loss of dopaminergic neurons. However mRNA expression of the dopamine receptors dDA1 and DAMB were significantly increased in sleep deprived alpha S flies. Blocking D1-like receptors during sleep deprivation prevented persistent shortterm memory deficits. Importantly, feeding flies the polyphenolic compound curcumin blocked long-term learning deficits.. These data emphasize the importance of sleep in a degenerating/reorganizing brain and shows that pathological processes induced by sleep deprivation can be dissected at the molecular and cellular level using Drosophila genetics.

Topics: Age Factors; alpha-Synuclein; Animals; Animals, Genetically Modified; Avoidance Learning; Choice Behavior; Curcumin; Drosophila melanogaster; Drosophila Proteins; Enzyme Inhibitors; Gene Expression Profiling; Humans; Inhibition, Psychological; Light; Maze Learning; Memory, Short-Term; Motivation; Neurotoxins; Oxidopamine; Parkinsonian Disorders; Receptors, Dopamine; Receptors, Dopamine D2; RNA, Messenger; Sleep Deprivation

Recent authors have concluded that Parkinson's disease (PD) is too heterogeneous to still be considered a single discrete disorder. They advise broadening the concept of PD to include genetic parkinsonisms, and discard Lewy pathology as the confirmatory biomarker. However, PD seen in the clinic is more homogeneous than often recognized if viewed from a long-term perspective. With appropriate diagnostic criteria, it is consistently associated with Lewy neuropathology, which should remain the gold standard for PD diagnostic confirmation. PD seen in the clinic has an inexorable course with eventual development of not only levodopa-refractory motor symptoms, but often cognitive dysfunction and prominent dysautonomia. This contrasts with homozygous parkin, PINK1 or DJ1 parkinsonism, characterized by young-onset (usually <40 years), and a comparatively benign course of predominantly levodopa-responsive symptoms without dementia or prominent dysautonomia. Parkin neuropathology is non-Lewy, with neurodegeneration predominantly confined to substantia nigra (and locus ceruleus), consistent with the limited clinical phenotype. Given the restricted and persistently levodopa-responsive phenotype, these familial cases might be considered "nigropathies". Based on emerging laboratory evidence linking parkin and PINK1 (and perhaps DJ1) to mitochondrial dysfunction, these nigropathies may represent nigral mitochondrial cytopathies. The dopaminergic substantia nigra is uniquely vulnerable to mitochondrial challenges, which might at least be partially attributable to large energy demands consequent to thin, unmyelinated axons with enormous terminal fields. Although sporadic PD is also associated with mitochondrial dysfunction, Lewy neurodegeneration represents a more pervasive disorder with perhaps a second, or different primary mechanism.

Topics: alpha-Synuclein; Disease Progression; Humans; Intracellular Signaling Peptides and Proteins; Male; Middle Aged; Mitochondria; Oncogene Proteins; Parkinson Disease; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Substantia Nigra; Ubiquitin-Protein Ligases

The reactive changes in different types of astrocytes were analyzed in parkinsonian syndromes in order to identify common reactions and their relationship to disease severity. Immunohistochemistry was used on formalin-fixed, paraffin-embedded sections from the putamen, pons, and substantia nigra from 13 Parkinson disease (PD), 29 multiple-system atrophy (MSA), 34 progressive supranuclear palsy (PSP), 10 corticobasal degeneration(CBD), and 13 control cases. Classic reactive astrocytes were observed in MSA, PSP, and CBD, but not PD cases; the extent of reactivity correlated with indices of neurodegeneration and disease stage. Approximately 40% to 45% of subcortical astrocytes in PD and PSP accumulated alpha-synuclein and phospho-tau, respectively; subcortical astrocytes in MSA and CBD cases did not accumulate these proteins. Protoplasmic astrocytes were identified from fibrous astrocytes by their expression of parkin coregulated gene and apolipoprotein D, and accumulated abnormal proteins in PD, PSP, and CBD, but not MSA. The increased reactivity of parkin coregulated gene-immunoreactive protoplasmic astrocytes correlated with parkin expression in PSP and CBD. Nonreactive protoplasmic astrocytes were observed in PD and MSA cases; in PD, they accumulated alpha-synuclein, suggesting that the attenuated response might be due to an increase in the level of alpha-synuclein. These heterogeneous astroglial responses in PD, MSA, PSP, and CBD indicate distinct underlying pathogenic mechanisms in each disorder.

Topics: alpha-Synuclein; Apolipoproteins D; Astrocytes; Glycoproteins; Humans; Immunohistochemistry; Membrane Transport Proteins; Multiple System Atrophy; Nerve Degeneration; Parkinson Disease; Parkinsonian Disorders; Phosphorylation; Pons; Putamen; Severity of Illness Index; Substantia Nigra; Supranuclear Palsy, Progressive; tau Proteins

A consensus conference on multiple system atrophy (MSA) in 1998 established criteria for diagnosis that have been accepted widely. Since then, clinical, laboratory, neuropathologic, and imaging studies have advanced the field, requiring a fresh evaluation of diagnostic criteria. We held a second consensus conference in 2007 and present the results here.. Experts in the clinical, neuropathologic, and imaging aspects of MSA were invited to participate in a 2-day consensus conference. Participants were divided into five groups, consisting of specialists in the parkinsonian, cerebellar, autonomic, neuropathologic, and imaging aspects of the disorder. Each group independently wrote diagnostic criteria for its area of expertise in advance of the meeting. These criteria were discussed and reconciled during the meeting using consensus methodology.. The new criteria retain the diagnostic categories of MSA with predominant parkinsonism and MSA with predominant cerebellar ataxia to designate the predominant motor features and also retain the designations of definite, probable, and possible MSA. Definite MSA requires neuropathologic demonstration of CNS alpha-synuclein-positive glial cytoplasmic inclusions with neurodegenerative changes in striatonigral or olivopontocerebellar structures. Probable MSA requires a sporadic, progressive adult-onset disorder including rigorously defined autonomic failure and poorly levodopa-responsive parkinsonism or cerebellar ataxia. Possible MSA requires a sporadic, progressive adult-onset disease including parkinsonism or cerebellar ataxia and at least one feature suggesting autonomic dysfunction plus one other feature that may be a clinical or a neuroimaging abnormality.. These new criteria have simplified the previous criteria, have incorporated current knowledge, and are expected to enhance future assessments of the disease.

Topics: alpha-Synuclein; Autonomic Nervous System Diseases; Basal Ganglia; Brain; Cerebellar Ataxia; Cerebellum; Diagnosis, Differential; Inclusion Bodies; Multiple System Atrophy; Parkinsonian Disorders

To clarify the genetic background of amyotrophic lateral sclerosis (ALS)/parkinsonism-dementia complex (PDC) of the Kii peninsula, Japan (Kii ALS/PDC), we performed extended mutation analyses of three patients with pathologically diagnosed Kii ALS/PDC. Direct sequencing analyses were performed in 19 genes, including ALS/frontotemporal lobar degeneration (FTLD)-related genes (SOD2, SOD3, ALS2/alsin, SMN1, PGRN, ANG, VEGF, VCP, VAPB, DCTN1, CHMP2B, and TARDBP or TDP-43), tauopathy-related gene (GSK3beta), and parkinsonism-related genes (alpha-synuclein, LRRK2, parkin, DJ-1, PINK1, and ATP13A2). Gene dosage analyses were conducted in screening of MAPT, alpha-synuclein, TDP-43 (or TARDBP), GSK3beta, and parkin. We found no mutation in the 19 genes. We found a homozygous nonsynonymous SNP (ALS2/alsin V368M) shared by all the three patients. Gene dosage was normal in MAPT, alpha-synuclein, TDP-43, GSK3beta, and parkin. The present findings, together with a previous negative study on MAPT and SOD1 mutation, further elucidated the lack of causative mutations in all exons, exon-intron boundaries, or some rearrangements of the reported major causative or susceptible genes related to ALS, FTLD, parkinsonism, synucleinopathy, TDP-43 proteinopathy, and tauopathy. However, the familial aggregation and lack of any environment factors suggest that Kii ALS/PDC is caused by other yet unidentified genetic factors.

Topics: Aged; alpha-Synuclein; Amyotrophic Lateral Sclerosis; Dementia; DNA Mutational Analysis; DNA-Binding Proteins; Family Health; Female; Glycogen Synthase Kinase 3; Humans; Japan; Male; Middle Aged; Mutation; Parkinsonian Disorders; tau Proteins; Ubiquitin-Protein Ligases

Guam ALS/PDC is a severe tangle forming disorder endemic to Guam with features overlapping such neurodegenerative disorders as Alzheimer disease (AD), Parkinson disease (PD), progressive supranuclear palsy (PSP), ALS, corticobasal degeneration (CBD) and pallido-ponto-nigral degeneration (PPND). Since the prevalence is declining, we examined brain tissue from 35 clinically diagnosed Chamorro patients with ALS/PDC and two Chamorro controls autopsied between 1946 and 2006, to determine if distinct variations in the pathology could be identified up to this time. Although the age at autopsy increased by 4.5-5 years per decade, we identified no qualitative differences in pathological deposits with antibodies against tau, ubiquitin, A beta, alpha-synuclein and TDP-43, indicating that these more recently identified proteins have been involved in the neuropathogenesis over the past 6 decades. Tau and TDP-43 positive neuronal, oligodendroglial and astrocytic inclusions involving multiple nerve fiber tracts occurred in both the ALS and PDC types, reinforcing the concept that these forms are part of the same disorder. The results obtained may help to define the commonality of the Guam disease with other tangle forming disorders and may help in monitoring the epidemiological changes that are taking place.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Autopsy; Brain; Brain Chemistry; Dementia; DNA-Binding Proteins; Female; Guam; Humans; Immunohistochemistry; Inclusion Bodies; Male; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; Neuroglia; Neurons; Parkinsonian Disorders; tau Proteins; Ubiquitin

Nicotinamide, the principal form of niacin (vitamin B3), has been proposed to be neuroprotective in Parkinson's disease. However, the effects and mechanisms of nicotinamide on motor function in animals and on mitochondrial function in cellular systems have not been well studied. We hypothesized that niacin-derived NAD(P)H as antioxidants and enzyme cofactors could inhibit oxidative damage and improve mitochondrial function and thus protect neurodegeneration and improve motor function. In the present study, the effects of nicotinamide on mitochondrial function and oxidative stress were studied in a 1-methyl-4-phenylpyridinium (MPP(+))-induced cellular model of Parkinson's disease, and the effects of improving motor dysfunction were studied in an alpha-synuclein transgenic Drosophila Parkinson's model. Mitochondrial function was tested by measuring the activity of mitochondrial complex I and alpha-ketoglutarate dehydrogenase, and oxidative damage was tested by measuring reactive oxygen species, DNA damage (8-oxo-7,8-dihydro-2'-deoxyguanosine and Comet assay), and protein oxidation (protein carbonyls) levels. Nicotinamide at a relatively higher concentration, that is, 100-fold of the level in the cell culture medium (101 mg/L), significantly protected SK-N-MC human neuroblastoma cells from an MPP(+)-induced decrease in cell viability, complex I and alpha-ketoglutarate dehydrogenase activity, and an increase in oxidant generation, DNA damage, and protein oxidation. In the Drosophila model, nicotinamide at 15 and 30 mg/100 g diet significantly improved climbing ability. These results suggest that nutritional supplementation of nicotinamide at high doses decreases oxidative stress and improves mitochondrial and motor function in cellular and/or Drosophila models and may be an effective strategy for preventing and ameliorating Parkinson's disease.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cell Line, Tumor; Cell Survival; Disease Models, Animal; DNA Damage; DNA, Mitochondrial; Drosophila; Humans; Ketoglutarate Dehydrogenase Complex; Mitochondria; Motor Activity; Neuroblastoma; Niacinamide; Oxidative Phosphorylation; Parkinsonian Disorders

Multiplication of the alpha-synuclein gene (SNCA) (OMIM 163890) has been identified as a causative mutation in hereditary Parkinson disease or dementia with Lewy bodies.. To determine the genetic, biochemical, and neuropathologic characteristics of patients with autopsy-confirmed autosomal dominant Lewy body disease, with particular reference to the dosage effects of SNCA.. Four-generation family study.. Academic research. Patients We fractionated samples extracted from frozen brain tissues of 4 patients for biochemical characterization, followed by immunoblot analysis.. We determined the dosages of SNCA and its surrounding genes by quantitative polymerase chain reaction analysis.. Quantitative polymerase chain reaction analysis revealed that 3 patients were heterozygous for SNCA duplication and 1 patient was homozygous for SNCA duplication. The homozygous patient showed earlier age at onset and earlier death, with more severe cognitive impairment than the heterozygous patients. Biochemical analysis revealed that phosphorylated alpha-synuclein accumulated in the sarkosyl-insoluble urea-extracted fraction of the brains of the patients.. Pathologically confirmed Lewy body disease clinically characterized by progressive parkinsonism and cognitive dysfunction is caused by SNCA duplication. The homozygous patient demonstrated the most severe phenotype, suggesting that SNCA dosage has a considerable effect on disease phenotype even within a family. SNCA duplication results in the hyperaccumulation of phosphorylated alpha-synuclein in the brains of patients.

Topics: Age of Onset; Aged; Alleles; alpha-Synuclein; Brain; Cognition Disorders; Consanguinity; DNA Mutational Analysis; Exons; Female; Gene Dosage; Gene Duplication; Genetic Carrier Screening; Homozygote; Humans; Lewy Bodies; Lewy Body Disease; Male; Microsatellite Repeats; Middle Aged; Neuropsychological Tests; Parkinsonian Disorders; Phosphorylation

The identification of mutations that cause familial Parkinson's disease (PD) provides a framework for studies into pathways that may be perturbed also in the far more common, non-familial form of the disorder. Following this hypothesis, we have examined the gene regulatory network that links alpha-synuclein and parkin pathways with dopamine metabolism in neuropathologically verified cases of sporadic PD. By means of an in silico approach using a database of eukaryotic molecular interactions and a whole genome transcriptome dataset validated by qRT-PCR and histological methods, we found parkin and functionally associated genes to be up-regulated in the lateral substantia nigra (SN). In contrast, alpha-synuclein and ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) gene expression levels were significantly reduced in both the lateral and medial SN in PD. Gene expression for Septin 4, a member of the GTP-binding protein family involved in alpha-synuclein metabolism was elevated in the lateral parkinsonian SN. Additionally, catalase and mitogen-activated protein kinase 8 and poly(ADP-ribose) polymerase family member 1 (PARP1) known to function in DNA repair and cell death induction, all members of the dopamine synthesis pathway, were up-regulated in the lateral SN. In contrast, two additional PD-linked genes, glucocerebrosidase and nuclear receptor subfamily 4, group A, member 2 (NR4A2) showed reduced expression. We show that in sporadic PD, parkin, alpha-synuclein and dopamine pathways are co-deregulated. Alpha-synuclein is a member of all three gene regulatory networks. Our analysis results support the view that alpha-synuclein has a central role in the familial as well as the non-familial form of the disease and provide steps towards a pathway definition of PD.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Dopamine; Female; Gene Expression Regulation; Humans; Male; Microarray Analysis; Middle Aged; Models, Biological; Parkinsonian Disorders; Signal Transduction; Substantia Nigra; Ubiquitin-Protein Ligases

Mutations in SNCA and LRRK2 genes, encoding alpha-synuclein and leucine-rich repeat kinase 2, respectively, cause autosomal dominant Parkinson's disease (AdPD). The LRRK2 G2019S (c.6055G > A) and R1441G (c.4321C > G) mutations have also been identified in sporadic PD (sPD). We studied 55 unrelated patients with AdPD, 235 patients with sPD, and 235 healthy age- and gender-matched controls all of Greek origin. Patients with AdPD were screened for SNCA and LRRK2 mutations by direct sequencing. SNCA gene dosage analysis was also performed for AdPD using quantitative duplex polymerase chain reaction of genomic DNA. In addition, we investigated the frequency of the LRRK2 G2019S mutation in sPD. We found no missense mutations or multiplications in the SNCA gene. Here we report two novel variants, A211V (c.632C > T) and K544E (c.1630A > G) in LRRK2 gene in two patients with AdPD that was not present in controls. We identified only one patient with sPD (1/235; 0.4%) carrying the G2019S mutation. LRRK2 mutations are present in AdPD and sPD patients of Greek origin.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Female; Genetic Testing; Genetic Variation; Greece; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Mutation; Parkinson Disease; Parkinsonian Disorders; Protein Serine-Threonine Kinases

The "Lister family complex," an extensive Swedish family with autosomal dominant Parkinson disease, was first described by Henry Mjönes in 1949. On the basis of clinical, molecular, and genealogic findings on a Swedish and an American family branch, we provide genetic evidence that explains the parkinsonism in this extended pedigree.. Clinical methods included a detailed neurologic exam of the proband of the Swedish family branch, MRI, and ([123]I)-beta-CIT SPECT imaging. Genomic analysis included alpha-synuclein sequencing, SNCA real-time PCR dosage, chromosome 4q21 microsatellite analysis, and high-resolution microarray genotyping. The geographic origin and ancestral genealogy of each pedigree were researched in the medical literature and Swedish Parish records.. The proband of the Swedish family branch presented with early dysautonomia followed by progressive parkinsonism suggestive of multiple system atrophy. Molecular analysis identified a genomic duplication of <0.9 Mb encompassing alpha-synuclein and multimerin 1 (SNCA-MMRN1), flanked by long interspersed repeat sequences (LINE L1). Microsatellite variability within the genomic interval was identical to that previously described for a Swedish American family with an alpha-synuclein triplication. Subsequent genealogic investigation suggested that both kindreds are ancestrally related to the Lister family complex.. Our findings extend clinical, genetic, and genealogical research on the Lister family complex. The genetic basis for familial parkinsonism is an SNCA-MMRN11 multiplication, but whereas SNCA-MMRN1 duplication in the Swedish proband (Branch J) leads to late-onset autonomic dysfunction and parkinsonism, SNCA-MMRN1 triplication in the Swedish American family (Branch I) leads to early-onset Parkinson disease and dementia.

Topics: Adult; Aged; alpha-Synuclein; Americas; Autonomic Nervous System Diseases; Blood Proteins; Chromosomes, Human, Pair 4; Dementia; DNA Mutational Analysis; Female; Gene Dosage; Genealogy and Heraldry; Genetic Predisposition to Disease; Genetic Testing; Humans; Male; Microsatellite Repeats; Middle Aged; Mutation; Oligonucleotide Array Sequence Analysis; Parkinsonian Disorders; Pedigree; Phenotype; Sweden; Tomography, Emission-Computed, Single-Photon

alpha-Synuclein is a primarily neuronal protein that is enriched at the pre-synapse. alpha-Synuclein and the microtubule binding protein tau have been implicated in neurodegenerative diseases. alpha-Synuclein is known to associate with phospholipid vesicles, regulates dopamine metabolism and exhibits chaperone activity, but its main role remains largely unknown. Furthermore, knowledge on its interactions and post-translational modifications is essential for a molecular understanding of alpha-synucleinopathies. We investigated alpha-synuclein mutations, causative for autosomal dominant forms of Parkinson's disease (A30P, A53T and E46K), and phosphorylation mutants at serine 129 (S129A and S129D) using fluorescently labelled alpha-synuclein, actin and tau. The investigation of colocalization, and protein-protein interactions by Förster resonance energy transfer and fluorescence lifetime imaging showed that alpha-synuclein associates with the actin cytoskeleton and interacts with tau. The A30P mutation and cytoskeletal destabilization decreased this interaction. Given the concurrent loss of membrane binding by this mutation, we propose a membrane-bound functional complex with tau that might involve the actin cytoskeleton.

Topics: Actins; alpha-Synuclein; Alzheimer Disease; Animals; Brain; Cell Membrane; CHO Cells; Cricetinae; Cricetulus; Cytoskeleton; Humans; Microscopy, Fluorescence; Mutation; Neurodegenerative Diseases; Neurons; Parkinsonian Disorders; Phosphorylation; Protein Binding; tau Proteins

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is primarily characterized by the degeneration of dopaminergic neurons in the nigrostriatal pathway. Previous studies have demonstrated that chronic systemic exposure of Lewis rats to rotenone produced many features of PD, and cerebral tauopathy was also detected in the case of severe weight loss. The present study was designed to assess the neurotoxicity of rotenone after daily oral administration for 28 days at several doses in C57BL/6 mice. In addition, we examined the protective effects of 4-phenylbutyrate (4-PBA) on nigral dopamine (DA) neurons in rotenone-treated mice. 4-PBA was injected intraperitoneally daily 30 min before each oral administration of rotenone. Chronic oral administration of rotenone at high doses induced specific nigrostriatal DA neurodegeneration, motor deficits and the up-regulation of alpha-synuclein in the surviving DA neurons. In contrast to the Lewis rat model, cerebral tauopathy was not detected in this mouse model. 4-PBA inhibited rotenone-induced neuronal death and decreased the protein level of alpha-synuclein. These results suggest that this rotenone mouse model may be useful for understanding the mechanism of DA neurodegeneration in PD, and that 4-PBA has a neuroprotective effect in the treatment of PD.

Topics: alpha-Synuclein; Animals; Cells, Cultured; Corpus Striatum; Disease Models, Animal; Dopamine; Endoplasmic Reticulum; Humans; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Oxidative Stress; Parkinsonian Disorders; Phenylbutyrates; Rotenone; Substantia Nigra; Tauopathies

Parkinsonism-dementia complex (PDC) remains a significant health burden to the Chamorro population. We tested the hypothesis that quantitative proteomics might provide fresh insight into this enigmatic illness by analyzing proteins resistant to surfactant extraction from patients with Alzheimer's disease (AD) or PDC and their matched controls using isobaric tags for relative and absolute quantification. In addition to the expected increase in abnormal frontal cortical Abeta peptides, tau, ubiquitin, and apolipoprotein E in AD, and tau in PDC, we identified alpha-synuclein (SNCA) as a major abnormal protein in PDC but not AD. We confirmed our isobaric tags for relative and absolute quantification findings by enzyme-linked immunosorbent assay in frontal and temporal cortices. We extended our assays to include a limited number of cases of progressive supranuclear palsy (PSP) and dementia with Lewy bodies; we observed increased abnormal tau but not SNCA in PSP, and abnormal SNCA in dementia with Lewy bodies that was quantitatively similar to PDC. Finally, soluble Abeta oligomers were selectively increased in AD but not PDC or PSP. These results show that frontal and temporal cortex in PDC is distinguished from AD and PSP by its accumulation of abnormal SNCA and suggest that PDC be considered a synucleinopathy as well as a tauopathy.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Cerebral Cortex; Guam; Humans; Middle Aged; Parkinsonian Disorders; Proteomics; Supranuclear Palsy, Progressive; Surface-Active Agents; Tandem Mass Spectrometry

Mutation of the parkin gene, which encodes an E3 ubiquitin-protein ligase, is the major cause of autosomal recessive juvenile parkinsonism (ARJP). Although various substrates for parkin have been identified, the mechanisms that regulate the ubiquitin ligase activity of parkin are poorly understood. Here we report that 14-3-3eta, a chaperone-like protein present abundantly in neurons, could bind to parkin and negatively regulate its ubiquitin ligase activity. Furthermore, 14-3-3eta could bind to the linker region of parkin but not parkin with ARJP-causing R42P, K161N, and T240R mutations. Intriguingly, alpha-synuclein (alpha-SN), another familial Parkinson's disease (PD) gene product, abrogated the 14-3-3eta-induced suppression of parkin activity. alpha-SN could bind tightly to 14-3-3eta and consequently sequester it from the parkin-14-3-3eta complex. PD-causing A30P and A53T mutants of alpha-SN could not bind 14-3-3eta, and failed to activate parkin. Our findings indicate that 14-3-3eta is a regulator that functionally links parkin and alpha-SN. The alpha-SN-positive and 14-3-3eta-negative control of parkin activity sheds new light on the pathophysiological roles of parkin.

Topics: 14-3-3 Proteins; alpha-Synuclein; Animals; Cells, Cultured; Enzyme Activation; Humans; Mice; Molecular Chaperones; Mutation; Parkinsonian Disorders; Protein Interaction Mapping; Protein Isoforms; Protein Structure, Tertiary; Substantia Nigra; Ubiquitin-Protein Ligases

Abnormalities in the function of alpha-synuclein are implicated in the pathogenesis of Parkinson's disease (PD). We found that alpha-synuclein-deficient mice are resistant to MPTP-induced degeneration of dopaminergic neurons. There was dose-dependent protection against loss of both dopamine in the striatum and dopamine transporter (DAT) immunoreactive neurons in the substantia nigra. These effects were not due to alterations in MPTP processing. We found that alpha-synuclein-deficient mice are also resistant to both malonate and 3-nitropropionic acid (3-NP) neurotoxicity. There was reduced generation of reactive oxygen species in alpha-synuclein-deficient mice following administration of 3-NP. These findings implicate alpha-synuclein as a modulator of oxidative damage, which has been implicated in neuronal death produced by MPTP and other mitochondrial toxins.

Topics: alpha-Synuclein; Animals; Malonates; Mice; Mice, Mutant Strains; Mitochondria; Neurons; Neurotoxins; Nitro Compounds; Parkinsonian Disorders; Propionates

Sporadic Parkinson's disease (PD) is most likely caused by a combination of environmental exposures and genetic susceptibilities, although there are rare monogenic forms of the disease. Mitochondrial impairment at complex I, oxidative stress, alpha-synuclein aggregation, and dysfunctional protein degradation, have been implicated in PD pathogenesis, but how they are related to each other is unclear. To further evaluated PD pathogenesis here, we used in vivo and in vitro models of chronic low-grade complex I inhibition with the pesticide rotenone. Chronic rotenone exposure in vivo caused oxidative modification of DJ-1, accumulation of alpha-synuclein, and proteasomal impairment. Interestingly, the effects become more regionally restricted such that systemic complex I inhibition eventually results in highly selective degeneration of the nigrostriatal pathway. DJ-1 modifications, alpha-synuclein accumulation, and proteasomal dysfunction were also seen in vitro and these effects could be prevented with alpha-tocopherol. Thus, chronic exposure to a pesticide and mitochondrial toxin brings into play three systems, DJ-1, alpha-synuclein, and the ubiquitin-proteasome system, and implies that mitochondrial dysfunction and oxidative stress link environmental and genetic forms of the disease.

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Disease Models, Animal; Electron Transport Complex I; Energy Metabolism; Humans; Insecticides; Male; Mitochondria; Nerve Degeneration; Neurons; Oncogene Proteins; Oxidative Stress; Parkinsonian Disorders; Peroxiredoxins; Proteasome Endopeptidase Complex; Protein Deglycase DJ-1; Rats; Rats, Inbred Lew; Rotenone; Signal Transduction; Substantia Nigra; Ubiquitin

Parkinson's disease (PD) is a common neurodegenerative disorder and is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Although many studies showed that the aggregation of alpha-synuclein might be involved in the pathogenesis of PD, its protective properties against oxidative stress remain to be elucidated. In this study, human wild type and mutant alpha-synuclein genes were fused with a gene fragment encoding the nine amino acid transactivator of transcription (Tat) protein transduction domain of HIV-1 in a bacterial expression vector to produce a genetic in-frame WT Tat-alpha-synuclein (wild type) and mutant Tat-alpha-synucleins (mutants; A30P and A53T), respectively, and we investigated the protective effects of wild type and mutant Tat-alpha-synucleins in vitro and in vivo. WT Tat-alpha-synuclein rapidly transduced into an astrocyte cells and protected the cells against paraquat induced cell death. However, mutant Tat-alpha-synucleins did not protect at all. In the mice models exposed to the herbicide paraquat, the WT Tat-alpha-synuclein completely protected against dopaminergic neuronal cell death, whereas mutants failed in protecting against oxidative stress. We found that these protective effects were characterized by increasing the expression level of heat shock protein 70 (HSP70) in the neuronal cells and this expression level was dependent on the concentration of transduced WT Tat-alpha-synuclein. These results suggest that transduced Tat-alpha-synuclein might protect cell death from oxidative stress by increasing the expression level of HSP70 in vitro and in vivo and this may be of potential therapeutic benefit in the pathogenesis of PD.

Topics: alpha-Synuclein; Animals; Astrocytes; Cell Death; Cell Survival; Gene Products, tat; Genetic Vectors; HSP70 Heat-Shock Proteins; Humans; Male; Mice; Mice, Inbred C57BL; Mutation; Nerve Degeneration; Neurons; Oxidative Stress; Paraquat; Parkinsonian Disorders; Protein Transport; Recombinant Fusion Proteins; Transduction, Genetic

Alpha-synuclein (alphaSyn) misfolding is associated with several devastating neurodegenerative disorders, including Parkinson's disease (PD). In yeast cells and in neurons alphaSyn accumulation is cytotoxic, but little is known about its normal function or pathobiology. The earliest defect following alphaSyn expression in yeast was a block in endoplasmic reticulum (ER)-to-Golgi vesicular trafficking. In a genomewide screen, the largest class of toxicity modifiers were proteins functioning at this same step, including the Rab guanosine triphosphatase Ypt1p, which associated with cytoplasmic alphaSyn inclusions. Elevated expression of Rab1, the mammalian YPT1 homolog, protected against alphaSyn-induced dopaminergic neuron loss in animal models of PD. Thus, synucleinopathies may result from disruptions in basic cellular functions that interface with the unique biology of particular neurons to make them especially vulnerable.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Cell Survival; Cells, Cultured; Disease Models, Animal; Dopamine; Drosophila; Endoplasmic Reticulum; Gene Expression; Gene Library; Golgi Apparatus; Humans; Mice; Nerve Degeneration; Neurons; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Protein Folding; Protein Transport; Proteins; rab GTP-Binding Proteins; rab1 GTP-Binding Proteins; Rats; Recombinant Fusion Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins

Aberrant aggregation of alpha-synuclein (alpha-syn) to form fibrils and insoluble aggregates has been implicated in the pathogenic processes of many neurodegenerative diseases. Despite the dramatic effects of dopamine in inhibiting the formation of alpha-syn fibrils by stabilization of oligomeric intermediates in cell-free systems, no studies have examined the effects of intracellular dopamine on alpha-syn aggregation. To study this process and its association with neurodegeneration, intracellular catechol levels were increased to various levels by expressing different forms of tyrosine hydroxylase, in cells induced to form alpha-syn aggregates. The increase in the steady-state dopamine levels inhibited the formation of alpha-syn aggregates and induced the formation of innocuous oligomeric intermediates. Analysis of transgenic mice expressing the disease-associated A53T mutant alpha-syn revealed the presence of oligomeric alpha-syn in nondegenerating dopaminergic neurons that do contain insoluble alpha-syn. These data indicate that intraneuronal dopamine levels can be a major modulator of alpha-syn aggregation and inclusion formation, with important implications on the selective degeneration of these neurons in Parkinson's disease.

Topics: 3,4-Dihydroxyphenylacetic Acid; alpha-Synuclein; Amino Acid Substitution; Animals; Catechols; Cell Differentiation; Cell Line, Tumor; Cerebral Cortex; Corpus Striatum; Cytosol; Dopamine; Humans; Levodopa; Mice; Mice, Transgenic; Mutation, Missense; Nerve Degeneration; Neuroblastoma; Oxidation-Reduction; Parkinson Disease; Parkinsonian Disorders; Protein Conformation; Recombinant Fusion Proteins; Solubility; Transfection; Tretinoin; Tyrosine 3-Monooxygenase

We report the case of an elderly man of Greek background who presented with progressive cognitive decline and motor parkinsonism on a background of a strong family history of Parkinson's disease. Associated symptoms included visual hallucinations, excessive daytime drowsiness, recurrent falls, orthostatic hypotension and urinary incontinence. His major clinical symptoms and signs fulfilled consensus criteria for a clinical diagnosis of dementia with Lewy bodies. An alpha-synuclein gene mutation analysis for the G209A substitution was positive. We conclude that the alpha-synuclein (G209A) gene mutation genotype should be considered in the differential diagnosis of dementia with Lewy bodies, particularly in patients with European ancestry and a family history of Parkinson's disease.

Topics: Accidental Falls; Aged; alpha-Synuclein; Cognition Disorders; Diagnosis, Differential; Disease Progression; DNA Mutational Analysis; Fatal Outcome; Genetic Markers; Genetic Predisposition to Disease; Genotype; Greece; Hallucinations; Humans; Hypotension, Orthostatic; Lewy Body Disease; Male; Mutation; Parkinsonian Disorders; Respiratory Tract Infections; Urinary Incontinence

Lrrk2 G2019S is predominantly associated with alpha-synuclein-immunopositive Lewy body pathology. We have identified Family SK where Lrrk2 G2019S segregates with slowly progressive parkinsonism and the affected proband has tau-immunopositive neurofibrillary tangle pathology. Thus alpha-synucleinopathy and tauopathy, the predominant pathologies associated with parkinsonism, may be alternate outcomes of the same underlying genetic cause. Intriguingly, we observe no evidence of a direct interaction between either the tau or alpha-synuclein protein with Lrrk2.

Topics: Aged; alpha-Synuclein; Brain; Cell Line; Disability Evaluation; Disease Progression; Female; Glycine; Humans; Immunohistochemistry; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Middle Aged; Mutation; Neurofibrillary Tangles; Parkinsonian Disorders; Pedigree; Protein Serine-Threonine Kinases; Serine; tau Proteins

Recent studies disclosed the relevance of specific molecules for the onset of Parkinson's disease (PD) and for the composition of neuronal inclusions. The scenario which is now emerging leads to identify a potential common pathway named the ubiquitin-proteasome (UP) system. In line with this, striatal or systemic inhibiton of the UP system causes experimental Parkinsonism characterized by the formation of neuronal inclusions. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which is also a complex I inhibitor, has been used for decades to produce experimental Parkinsonism with no evidence for neuronal inclusions in rodents. This leaves open the question whether neuronal inclusions need an alternative mechanism or the inhibition of complex I needs to be carried out continuously to build up inclusions. In the present article, we administered continuously MPTP. In these experimental conditions we compared the neurological consequence of intermittent versus continuous MPTP. In both cases we observed a severe dopamine (DA) denervation and cell loss. However, when MPTP was delivered continuously, spared DA nigral neurons develop ubiquitin, parkin, and alpha-synuclein positive inclusions, which are not detectable after intermittent dosing. The onset of Parkinsonism is associated with inhibition of the UP system. We compared these results with those obtained with amphetamine derivative in vivo and in vitro in which occurrence of neuronal inclusions was associated with inhibition of the UP system and we evaluated the role of DA metabolism in inducing these effects.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Dopamine; Dopamine Agents; Dose-Response Relationship, Drug; Methamphetamine; Neurotoxins; Parkinsonian Disorders; PC12 Cells; Proteasome Endopeptidase Complex; Rats; Substantia Nigra; Ubiquitin

Alpha-synuclein (alpha-syn), a protein implicated in Parkinson's disease pathogenesis, is a presynaptic protein suggested to regulate transmitter release. We explored how alpha-syn overexpression in PC12 and chromaffin cells, which exhibit low endogenous alpha-syn levels relative to neurons, affects catecholamine release. Overexpression of wild-type or A30P mutant alpha-syn in PC12 cell lines inhibited evoked catecholamine release without altering calcium threshold or cooperativity of release. Electron micrographs revealed that vesicular pools were not reduced but that, on the contrary, a marked accumulation of morphologically "docked" vesicles was apparent in the alpha-syn-overexpressing lines. We used amperometric recordings from chromaffin cells derived from mice that overexpress A30P or wild-type (WT) alpha-syn, as well as chromaffin cells from control and alpha-syn null mice, to determine whether the filling of vesicles with the transmitter was altered. The quantal size and shape characteristics of amperometric events were identical for all mouse lines, suggesting that overexpression of WT or mutant alpha-syn did not affect vesicular transmitter accumulation or the kinetics of vesicle fusion. The frequency and number of exocytotic events per stimulus, however, was lower for both WT and A30P alpha-syn-overexpressing cells. The alpha-syn-overexpressing cells exhibited reduced depression of evoked release in response to repeated stimuli, consistent with a smaller population of readily releasable vesicles. We conclude that alpha-syn overexpression inhibits a vesicle "priming" step, after secretory vesicle trafficking to "docking" sites but before calcium-dependent vesicle membrane fusion.

Topics: alpha-Synuclein; Animals; Calcium; Calcium Signaling; Catecholamines; Chromaffin Cells; Disease Models, Animal; Dopamine; Exocytosis; Female; Male; Membrane Fusion; Mice; Mice, Knockout; Mice, Transgenic; Neurons; Parkinsonian Disorders; PC12 Cells; Rats; Secretory Vesicles; Synaptic Membranes; Synaptic Transmission; Synaptic Vesicles; Time Factors

Adult polyglucosan body disease (APGBD) is a rare disorder affecting the central and peripheral nervous systems and in which parkinsonism is unusual. A 71-year-old man presented levodopa-unresponsive parkinsonism with urinary incontinence and recurrent syncopes of 6 years standing masquerading as atypical parkinsonism of the multiple system atrophy (MSA-P) type. Brain histopathology demonstrated massive accumulation of polyglucosan bodies particularly in the putamen. In addition, there were dense alpha-synuclein-positive cytoplasmic oligodendroglial inclusions in the pons and in the middle cerebellar peduncle. These inclusions may be either due to the chance association of MSA-P with APGBD, or pathologically related to APGBD.

Topics: Aged; alpha-Synuclein; Glial Fibrillary Acidic Protein; Glucans; Humans; Immunohistochemistry; Inclusion Bodies; Lewy Bodies; Male; Multiple System Atrophy; Nerve Tissue Proteins; Parkinsonian Disorders; Review Literature as Topic; Staining and Labeling; Synucleins

We recently reported here that SNCA triplication results in a doubling in the amount of alpha-synuclein protein in blood from cases with hereditary Lewy body disease. This observation shows that alpha-synuclein levels in blood accurately reflect gene dosage, which we assume drives pathogenesis in these individuals. A previous report has suggested that parkin can affect alpha-synuclein metabolism in human brain. Here we have tested whether there is also an increase of alpha-synuclein in autosomal recessive juvenile Parkinsonism (ARJP). We find there is not and discuss this result in terms of the putative relationships between alpha-synuclein and parkin.

Topics: alpha-Synuclein; Blotting, Western; Exons; Family Health; Gene Deletion; Gene Dosage; Humans; Nerve Tissue Proteins; Parkinsonian Disorders; Synucleins; Ubiquitin-Protein Ligases

In animals, sporadic injections of the mitochondrial toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively damage dopaminergic neurons but do not fully reproduce the features of human Parkinson's disease. We have now developed a mouse Parkinson's disease model that is based on continuous MPTP administration with an osmotic minipump and mimics many features of the human disease. Although both sporadic and continuous MPTP administration led to severe striatal dopamine depletion and nigral cell loss, we find that only continuous administration of MPTP produced progressive behavioral changes and triggered formation of nigral inclusions immunoreactive for ubiquitin and alpha-synuclein. Moreover, only continuous MPTP infusions caused long-lasting activation of glucose uptake and inhibition of the ubiquitin-proteasome system. In mice lacking alpha-synuclein, continuous MPTP delivery still induced metabolic activation, but induction of behavioral symptoms and neuronal cell death were almost completely alleviated. Furthermore, the inhibition of the ubiquitinproteasome system and the production of inclusion bodies were reduced. These data suggest that continuous low-level exposure of mice to MPTP causes a Parkinson-like syndrome in an alpha-synuclein-dependent manner.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Male; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Synucleins; Ubiquitin

Extrapyramidal signs (EPS) are common in Alzheimer disease (AD) and increase in prevalence as AD advances. The neuropathologic substrate responsible for EPS in AD remains to be fully characterized.. Subjects had a clinical diagnosis of AD confirmed by neuropathologic examination. EPS during life were documented by clinical methods assessing bradykinesia, cogwheel rigidity, rest tremor, and parkinsonian gait. Subjects with EPS and previous neuroleptic exposure were excluded. Twenty-eight subjects were in the EPS group and 104 subjects were without EPS. Neuron loss, alpha-synuclein (ASYN)-labeled pathology, and tau-labeled pathology in the substantia nigra were measured using semiquantitative techniques such that higher scores represented increased pathologic burden.. Presence of nigral ASYN-labeled pathology was more common (50 vs 28.9%; p < 0.05) in the EPS group than in those without EPS. There was more nigral neuron loss in the EPS group (1.50 vs 1.11 in no-EPS group; p < 0.05). Tau-labeled burden was not different by group comparisons; however, EPS onset at later stages of dementia severity was associated with increased tau-labeled pathology (Kendall tau-B = 0.48, p < 0.01) and this association remained after controlling for dementia severity at death. Additionally, moderate to severe tau burden was more common in the subgroup with "pure AD" (definite AD without other neuropathology) with EPS (81.8%) than cases without EPS (49.0%; p < 0.05). Four subjects with EPS (14.3%) had little to no significant nigral pathologic changes.. Clinically detected extrapyramidal signs (EPS) in Alzheimer disease (AD) are associated with substantia nigra pathology including alpha-synuclein aggregation, hyperphosphorylated tau accumulation, and neuron loss that may account for the increasing prevalence of EPS as AD progresses. In some cases, limited nigral pathology suggests extranigral factors in the clinical symptoms of EPS.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Autopsy; Female; Humans; Lewy Bodies; Longitudinal Studies; Male; Middle Aged; Nerve Degeneration; Neurofibrillary Tangles; Neurons; Neuropsychological Tests; Parkinsonian Disorders; Substantia Nigra; tau Proteins

We examined 7 patients from a family harboring a novel mutation in the alpha-synuclein gene (E46K) that segregated with a phenotype of parkinsonism and dementia with Lewy bodies. An abnormal restless sleep was the presenting symptom in 2 of them. Polysomnographic (PSG) studies were performed in 4 of the 7 patients and in 2 asymptomatic carriers of the mutation. A severe loss of both rapid eye movement (REM) and non-REM sleep was observed in 2 patients complaining of insomnia and in a third parkinsonian member of the family who did not complain of trouble with sleeping. Another parkinsonian family member had a mild disorganization of the sleep architecture. The 2 asymptomatic carriers also had minor changes in the PSG findings. Episodes of bizarre behavior at night were reported historically in the 2 symptomatic patients, but we did not observed the behaviors during the PSG studies. REM sleep behavior disorder could not be recorded in any case. Our findings expand the spectrum of sleep disorders reported in synucleinopathies whether sporadic or familial.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Diagnosis, Differential; DNA Mutational Analysis; Electroencephalography; Electromyography; Electrooculography; Female; Humans; Lewy Body Disease; Male; Middle Aged; Parkinsonian Disorders; Pedigree; Point Mutation; Polysomnography; REM Sleep Behavior Disorder; Restless Legs Syndrome; Sleep Initiation and Maintenance Disorders

Changes in the expression of alpha-synuclein are likely to underlie its normal function as well as its role in pathological processes. The relationship between toxic injury and alpha-synuclein expression was assessed in the substantia nigra of squirrel monkeys treated with a single injection of MPTP and sacrificed 1 week or 1 month later. At 1 week, when stereological cell counting revealed only a small decrease (-10%) in the number of dopaminergic neurons, alpha-synuclein mRNA and protein were markedly enhanced. Increased alpha-synuclein immunoreactivity was evident at the level of neuronal fibers whereas nigral cell bodies were devoid of detectable protein. At 1 month post-MPTP, neuronal loss rose to 40%. Both alpha-synuclein mRNA and protein remained elevated but, noticeably, a robust alpha-synuclein immunoreactivity characterized a significant number of cell bodies. Neuromelanin granules are hallmarks of dopaminergic neurons in primates. Therefore, the number of alpha-synuclein-positive cells that also contained neuromelanin was counted throughout the substantia nigra. At 1 month, the vast majority of alpha-synuclein-immunoreactive neurons contained neuromelanin, and approximately 80% of the dopaminergic cell bodies that survived MPTP toxicity stained positive for alpha-synuclein. The results indicate that a single toxic insult is capable of inducing a sustained alpha-synuclein up-regulation in the primate brain. They support a direct relationship between neuronal injury and enhanced alpha-synuclein expression, and suggest that protein elevation within cell bodies may be a late feature of neurons that have endured a toxic stress.

Topics: alpha-Synuclein; Animals; Cell Count; Cell Death; Disease Models, Animal; Dopamine; Female; Melanins; Nerve Degeneration; Neurons; Oxidative Stress; Parkinsonian Disorders; RNA, Messenger; Saimiri; Substantia Nigra; Up-Regulation

A30P and A53T mutations of the presynaptic protein alpha-synuclein are associated with familial forms of Parkinson disease. NMR spectroscopy demonstrates that Parkinsonism-linked mutations greatly perturb specific tertiary interactions essential for the native state of alpha-synuclein. However, alpha-synuclein is not completely unfolded but exhibits structural fluctuations on the time scale of secondary structure formation and loses its native conformation gradually when protein stability decreases. The redistribution of the ensemble of alpha-synuclein conformers may underlie toxic gain-of-function by fostering self-association and altered binding affinity to ligands and receptors.

Topics: alpha-Synuclein; Amino Acid Sequence; Humans; Molecular Sequence Data; Mutation; Nerve Tissue Proteins; Nuclear Magnetic Resonance, Biomolecular; Parkinsonian Disorders; Protein Folding; Protein Isoforms; Protein Structure, Secondary; Protein Structure, Tertiary; Sequence Alignment; Synucleins

Multiple system atrophy (MSA) is a sporadic adult-onset neurodegenerative disorder of unknown etiology clinically characterized by a combination of parkinsonian, pyramidal, and cerebellar signs. Levodopa-unresponsive parkinsonism is present in 80% of MSA cases, and this dominant clinical presentation (MSA-P) is associated with a combined degeneration of the substantia nigra pars compacta and the striatum in anatomically related areas. The limited knowledge of the pathophysiology of MSA and the lack of therapeutic strategies prompted the development of lesion models reproducing striatonigral degeneration, the substrate of levodopa-unresponsive parkinsonism in MSA-P. This method was carried out first in rats with two different stereotaxic strategies using either two neurotoxins ("double toxin-double lesion") or a single neurotoxin ("single toxin-double lesion"). Double-lesioned rat models showed severe motor impairment compared to those with a single nigral or striatal lesion and helped to mimic different stages of the disease. Systemic models were also developed in mice and primates using the nigral toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and the striatal toxin 3-nitropropionic (3-NP). In mice, although MPTP reduced the subsequent sensitivity to 3-NP in a sequential lesion, simultaneous nigral and striatal insults were shown to exacerbate striatal damage. MPTP-treated monkeys displayed a significant worsening of parkinsonism and a loss of levodopa-responsiveness after the appearance of hindlimb dystonia and striatal lesion formation induced by subsequent 3-NP intoxication. The different species and intoxication paradigms used will be useful to investigate functional changes in substantia nigra and striatum and to define neuroprotective, neurorestorative, or symptomatic therapeutic strategies.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Corpus Striatum; Levodopa; Macaca fascicularis; Mice; MPTP Poisoning; Multiple System Atrophy; Oxidopamine; Parkinsonian Disorders; Point Mutation; Rats; Substantia Nigra

Serofendic acid was recently identified as a neuroprotective factor from fetal calf serum. This study was designed to evaluate the neuroprotective effects of an intranigral microinjection of serofendic acid based on behavioral, neurochemical and histochemical studies in hemi-parkinsonian rats using 6-hydroxydopamine (6-OHDA). Rats were injected with 6-OHDA in the presence or absence of serofendic acid, or were treated with serofendic acid on the same lateral side, at 12, 24 or 72 h after 6-OHDA lesion. Intranigral injection of 6-OHDA alone induced a massive loss of tyrosine hydroxylase (TH)-immunopositive neurons in the substantia nigra pars compacta (SNpc). Either simultaneous or 12 h post-administration of serofendic acid significantly prevented both dopaminergic neurodegeneration and drug-induced rotational asymmetry. Immunoreactivities for oxidative stress markers, such as 3-nitrotyrosine (3-NT) and 4-hydroxy-2-nonenal (4-HNE), were markedly detected in the SNpc of rats injected with 6-OHDA alone. These immunoreactivities were markedly suppressed by the co-administration of serofendic acid, similar to the results in vehicle-treated control rats. In addition, serofendic acid inhibited 6-OHDA-induced alpha-synuclein expression and glial activation in the SNpc. These results suggest that serofendic acid protects against 6-OHDA-induced SNpc dopaminergic neurodegeneration in a rat model of Parkinson's disease.

Topics: Adrenergic Agents; Aldehydes; alpha-Synuclein; Animals; Behavior, Animal; Blotting, Western; CD11b Antigen; Cell Count; Cell Line; Disease Models, Animal; Diterpenes; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Interactions; Functional Laterality; Glial Fibrillary Acidic Protein; Humans; Immunohistochemistry; Male; Neurodegenerative Diseases; Neuroprotective Agents; Oxidopamine; Parkinson Disease, Secondary; Parkinsonian Disorders; Rats; Rats, Wistar; Reactive Oxygen Species; Rotarod Performance Test; Rotation; Substantia Nigra; Synaptophysin; Time Factors; Tyrosine; Tyrosine 3-Monooxygenase

We have generated a transgenic mouse line overexpressing mutated human A30P alpha-synuclein under the control of the prion-related protein promoter. Immunohistology revealed mutated human A30P alpha-synuclein protein in numerous brain areas, but no gross morphological changes, Lewy bodies, or loss of dopaminergic cell bodies. The transgenic mice displayed decreased locomotion, impaired motor coordination, and balance. In vivo voltammetry showed that A30P mice responded to longer stimulation of the ascending dopaminergic pathways with less dopamine release in striatum and had a slower rate of dopamine decline after repeated stimulations or after alpha-methyl-p-tyrosine-HCl treatment. However, dopamine re-uptake or transporter levels were similar in transgenic and control mice. Our data provide evidence that overexpression of mutated human A30P alpha-synuclein in mice leads to a reduced size of the dopamine storage pool. This is in agreement with the previously postulated involvement of alpha-synuclein in the turnover of transmitter vesicles and may explain the observed motor deficits in A30P mice.

Topics: alpha-Methyltyrosine; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Dopamine Plasma Membrane Transport Proteins; Electric Stimulation; Enzyme Inhibitors; Humans; Mice; Mice, Inbred C57BL; Mice, Neurologic Mutants; Mice, Transgenic; Motor Activity; Mutation; Neural Pathways; Parkinsonian Disorders; Substantia Nigra; Synaptic Transmission; Synaptic Vesicles

Biochemical and genetic abnormalities of alpha-synuclein (alpha-Syn) are implicated in the pathogenesis of Parkinson's disease (PD) and other alpha-synucleinopathies. The abnormal intraneuronal accumulations of alpha-Syn in Lewy bodies (LBs) and Lewy neurites (LNs) have implicated defects in axonal transport of alpha-Syn in the alpha-synucleinopathies. Using human (Hu) alpha-Syn transgenic (Tg) mice, we have examined whether familial PD (FPD)-linked mutations (A30P and A53T) alter axonal transport of Hualpha-Syn. Our studies using peripheral nerves show that Hualpha-Syn and Moalpha-Syn are almost exclusively transported in the slow component (SC) of axonal transport and that the FPD-linked alpha-Syn mutations do not have obvious effects on the axonal transport of alpha-Syn. Moreover, older pre-symptomatic A53T Hualpha-Syn Tg mice do not show gross alterations in the axonal transport of alpha-Syn and other proteins in the SC, indicating that the early stages of alpha-synucleinopathy in A53T alpha-Syn Tg mice are not associated with gross alterations in the slow axonal transport. However, the axonal transport of alpha-Syn slows significantly with aging. Because the rate of axonal transport affects the stability and accumulation of proteins in axons, age-dependent-slowing alpha-Syn is a likely contributor to axonal aggregation of alpha-Syn in alpha-synucleinopathy.

Topics: Aging; alpha-Synuclein; Animals; Axonal Transport; Humans; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Peripheral Nerves; Synucleins

Genomic triplication of the alpha-synuclein gene recently has been associated with familial Parkinson's disease in the Spellman-Muenter kindred. Here, we present an independent family, of Swedish-American descent, with hereditary early-onset parkinsonism with dementia due to alpha-synuclein triplication. Brain tissue available from affected individuals in both kindreds provided the opportunity to compare their clinical, pathological, and biochemical phenotypes. Of note, studies of brain mRNA and soluble protein levels demonstrate a doubling of alpha-synuclein expression, consistent with molecular genetic data. Pathologically, cornu ammonis 2/3 hippocampal neuronal loss appears to be a defining feature of this form of inherited parkinsonism. The profound implications of alpha-synuclein overexpression for idiopathic synucleinopathies are discussed.

Topics: alpha-Synuclein; Brain; DNA Mutational Analysis; Electrophoresis, Polyacrylamide Gel; Gene Dosage; Gene Expression; Humans; Male; Middle Aged; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Parkinsonian Disorders; Pedigree; Polymerase Chain Reaction; RNA, Messenger; Synucleins

Amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a progressive neurodegenerative disease affecting the indigenous Chamorro population of Guam. Neuropathologically, PDC is characterized by neuronal loss in the substantia nigra pars compacta with severe widespread neurofibrillary tangles (NFTs) similar to those observed in Alzheimer's disease (AD), and is thus considered a tauopathy. Following reports of alpha-synuclein pathology in PDC patients of Guam, PDC has also been neuropathologically classified as a synucleinopathy. Recently, the presence of alpha-synuclein-positive bodies has been reported in the cerebellum of some patients with Parkinson's disease (PD), diffuse Lewy body disease (DLBD), or multiple system atrophy (MSA). Using immunohistochemical techniques, we investigated the deposition of alpha-synuclein in the cerebellum of Guamanian PDC patients. Numerous alpha-synuclein-immunoreactive spherical structures were found in the molecular layer of the cerebellum of 63.6% of PDC patients. These structures were only seen in patients showing alpha-synuclein pathology in the amygdala. The average density of alpha-synuclein-immunoreactive structures in the cerebellum of Guamanian PDC patients was almost an order of magnitude higher than in non-Guamanian PD patients, and this alpha-synuclein pathology was much more pronounced in the hemisphere than in the vermis. In addition, double immunohistochemistry revealed that cerebellar alpha-synuclein is co-localized with the neuronal marker calbindin and with glial-fibrillary acidic protein, suggesting the involvement of Purkinje cells and Bergmann glia. These findings demonstrate that the alpha-synuclein pathology in PDC of Guam affects not only the amygdala, but also the cerebellum, where it appears to involve both Purkinje cells and specialized astrocytes.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amygdala; Calbindins; Cell Count; Cerebellum; Dementia; Female; Glial Fibrillary Acidic Protein; Guam; Humans; Immunohistochemistry; Male; Middle Aged; Nerve Tissue Proteins; Neuroglia; Neurons; Parkinsonian Disorders; S100 Calcium Binding Protein G; Synucleins

Mutation A30P in the alpha-synuclein gene is a cause of familial Parkinson disease. Transgenic mice expressing wild mouse and mutant human A30P alpha-synuclein, Tg5093 mice (Tg), show a progressive motor disorder characterized by tremor, rigidity, and dystonia, accompanied by accumulation of alpha-synuclein in the soma and neurites and by a conspicuous gliosis beginning in the hippocampal formation at the age of 7 to 8 months and spreading throughout the CNS. Impaired short-term changes in synaptic strength have also been documented in hippocampal slices from Tg mice. Alpha-synuclein aggregates of approximately 34 and 70 kDa, in addition to the band of 17 kDa, corresponding to the molecular weight of alpha-synuclein, were recovered in the PBS-soluble fraction of brain homogenates from Tg mice but not from brain samples from age-matched wildtype littermates. MPTP-treated Tg and wildtype mice produced alpha-synuclein aggregates in the PBS-, deoxycholate-, and SDS-soluble fractions. Aggregates of alpha-synuclein, although with different molecular weights, were also observed in rotenone-treated Tg and wildtype mice. Pull-down studies with members of the Rab protein family have shown that alpha-synuclein from Tg mice interacts with Rab3a, Rab5, and Rab8. This binding is not due to the amount of alpha-synuclein (levels of which are higher in Tg mice) and it is not dependent on the amount of Rab protein used in the assay. Rather, alpha-synuclein interactions with Rab proteins are due to mutant alpha-synuclein as demonstrated in Rab pull-down assays with recombinant of wildtype and mutant A30P human alpha-synuclein. Since Rab3a, Rab5, and Rab8 are important proteins involved in synaptic vesicle trafficking and exocytosis at the synapse, vesicle endocytosis, and trans-Golgi transport, respectively, it can be suggested that these functions are impaired in Tg mice. This rationale is consistent with previous data showing that short-term hippocampal synaptic plasticity is altered and that alpha-synuclein accumulates in the cytoplasm of neurons in Tg mice.

Topics: alpha-Synuclein; Animals; Blotting, Western; Brain; Humans; Mice; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Precipitin Tests; rab1 GTP-Binding Proteins; Synucleins

alpha-Synuclein phosphorylated at Ser129 is the main component of Lewy bodies of Parkinson's and closely related diseases. We studied, by quantitative immunoblotting, changes in the phosphorylation level of alpha-synuclein in the mouse brains subjected to cold water stress. Relative basal level of alpha-synuclein phosphorylation at Ser129 was 40% higher in the striatum compared with the hippocampus. The phosphorylation level decreased to 57% in the striatum 20 min after 5 min of cold water stress, and also in the hippocampus and cortex to lesser degrees. Recovery to basal levels took place over several hours. The stress-induced temporary dephosphorylation was of smaller magnitude in the striatum of aged (18 months) mice. These results show that alpha-synuclein phosphorylation level at Ser129 in vivo responds to physiological stimuli. Relative prominence and age sensitivity of this phenomenon in the striatum may be relevant to the pathogenesis of Parkinson's disease.

Topics: Aging; alpha-Synuclein; Animals; Brain; Cerebral Cortex; Corpus Striatum; Hippocampus; Male; Mice; Mice, Inbred C57BL; Models, Biological; Nerve Tissue Proteins; Parkinsonian Disorders; Phosphorylation; Phosphoserine; Stress, Physiological; Synucleins

Missense mutations and genomic multiplications of the alpha-synuclein gene (SNCA) have been linked to autosomal dominant familial Parkinson's disease. We screened 50 probands of families with autosomal dominant parkinsonism for alpha-synuclein mutations by exon sequencing. No known or novel mutations were found. We also analyzed the genomic DNA for multiplications of the SNCA locus using multiplex panels of microsatellite markers. All samples were diploid with two normal copies of the SNCA locus. Hence, alpha-synuclein missense mutations and SNCA genomic multiplications remain a rare cause of disease.

Topics: Adult; Age Factors; Alanine; alpha-Synuclein; DNA Mutational Analysis; Exons; Family Health; Female; Humans; Male; Middle Aged; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Polymorphism, Single Nucleotide; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synucleins; Threonine

To report an autopsy case of an autosomal recessive juvenile parkinsonism patient with a homozygous exon 3 deletion in the parkin gene and alpha-synuclein-positive inclusions.. The representative areas of the brain were embedded in paraffin, stained with hematoxylin-eosin, Klüver-Barrera, and Gallyas-Braak stainings. Immunohistochemically, some of the specimens were used for immunostaining with the antibodies to alpha-synuclein, ubiquitin, and phosphorylated tau (AT8). Immunoreaction was visualized by the streptavidin-biotin-peroxidase complex method.. Histologically, the lesions of the brain were limited to the dopaminergic neuron system such as the substantia nigra (SN) and locus ceruleus. Melanin-containing neurons in the pars compacta of the SN were moderately to severely depleted, accompanied by gliosis. In the locus ceruleus, neurons were mildly decreased and extraneuronal melanin pigments were seen. Lewy bodies were not observed in the neuropils of the pars compacta of the SN or locus ceruleus. However, basophilic inclusion bodies were only occasionally observed in the neuropils of the pedunculopontine nucleus in the mesencephalic reticular formation. Immunohistochemistry with antibodies to alpha-synuclein and ubiquitin showed alpha-synuclein- and ubiquitin-positive inclusions in the neuropils of the pedunculopontine nucleus, which had a doughnut or round shape.. A variety of parkin gene abnormalities may produce pathologic differences in the degree and distribution of neuronal degeneration, including the absence or presence of Lewy bodies. A relationship between parkin-induced parkinsonism and idiopathic Parkinson disease (PD) may exist.

Topics: Aged; alpha-Synuclein; Brain; DNA Mutational Analysis; Exons; Female; Genes, Recessive; Genetic Heterogeneity; Humans; Inclusion Bodies; Melanins; Middle Aged; Nerve Tissue Proteins; Neurons; Parkinson Disease; Parkinsonian Disorders; Polymerase Chain Reaction; Sequence Deletion; Synucleins; Ubiquitin; Ubiquitin-Protein Ligases

One of the prominent pathological features of Parkinson's disease (PD) is the abnormal accumulation of iron in the substantia nigra pars compacta (SNpc), in the reactive microglia, and in association with neuromelanin, within the melanin-containing dopamine (DA) neurons. Lewy body, the morphological hallmark of PD, is composed of lipids, redox-active iron, and aggregated alpha-synuclein, concentrating in its peripheral halo and ubiquitinated, hyperphosphorylated, neurofilament proteins. The capacity of free iron to enhance and promote the generation of toxic reactive oxygen radicals has been discussed numerous times. Recent observations, that iron induces aggregation of inert alpha-synuclein to toxic aggregates, have reinforced the critical role of iron in oxidative stress-induced pathogenesis of DA neuron degeneration and protein degradation via ubiquitination. N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)- and 6-hydroxydopamine-induced neurodegeneration in rodents and nonhuman primates is associated with increased presence of iron and alpha-synuclein in the SNpc. The accumulation of iron in MPTP-induced neurodegeneration has been linked to nitric oxide-dependent mechanism, resulting in degradation of prominent iron regulatory proteins by ubiquitination. Radical scavengers such as R-apomorphine and green tea catechin polyphenol (-)-epigallocatechin-3-gallate, as well as the recently developed brain-permeable VK-28 series derivative iron chelators, which are neuroprotective against these neurotoxins in mice and rats, prevent the accumulation of iron and alpha-synuclein in SNpc. This study supports the notion that a combination of iron chelation and antioxidant therapy, as emphasized on several occasions, might be a significant approach to neuroprotection in PD and other neurodegenerative diseases.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Apomorphine; Catechin; Disease Models, Animal; Free Radicals; Iron; Iron Chelating Agents; Lewy Bodies; Male; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Neuroprotective Agents; Oxidative Stress; Parkinsonian Disorders; Substantia Nigra; Synucleins; Ubiquitin

Previous studies demonstrated that chronic systemic exposure to the pesticide and mitochondrial toxin rotenone through jugular vein cannulation reproduced many features of Parkinson's disease (PD) in rats, including nigrostriatal dopaminergic degeneration and formation of alpha-synuclein-positive cytoplasmic inclusions in nigral neurons (R. Betarbet et al., 2000, Nat. Neurosci. 3, 1301-1306). Although novel and conceptually important, the rotenone model of PD suffered from being extremely labor-intensive. The current paper demonstrates that these same features of PD can be reproduced by chronic, systemic exposure to rotenone following implantation of subcutaneous osmotic pumps. Chronic subcutaneous exposure to low doses of rotenone (2.0-3.0 mg/kg/day) caused highly selective nigrostriatal dopaminergic lesions. Striatal neurons containing DARPP-32 (dopamine and cAMP-regulated phosphoprotein) remained intact with normal morphology, and NeuN staining revealed normal neuronal nuclear morphology. Neurons of the globus pallidus and subthalamic nucleus were spared. Subcutaneous rotenone exposure caused alpha-synuclein-positive cytoplasmic aggregates in nigral neurons. This new protocol for chronic rotenone administration is a substantial improvement in terms of simplicity and throughput.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Infusion Pumps, Implantable; Injections, Subcutaneous; Insecticides; Male; Nerve Tissue Proteins; Neural Pathways; Neurodegenerative Diseases; Neurons; Parkinsonian Disorders; Rats; Rats, Inbred Lew; Rotenone; Substantia Nigra; Synucleins; Time; Tyrosine 3-Monooxygenase

Type 1 Gaucher disease is considered the non-neuronopathic form of this autosomal recessively inherited lysosomal storage disease. We report the simultaneous occurrence of Gaucher disease with parkinsonian in four adult patients. The patients had a relatively early onset of parkinsonian manifestations, and their disease was rapidly progressive and refractory to therapy. Each had a different Gaucher genotype, although four alleles carried the common N370S mutation. No mutations were identified in the genes for parkin or alpha-synuclein. The concurrence of these two phenotypes, both in this series of patients and in others in the literature, suggests a shared pathway, modifier, or other genetic etiology.

Topics: Alleles; alpha-Synuclein; Female; Gaucher Disease; Genotype; Humans; Jews; Ligases; Male; Middle Aged; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Phenotype; Synucleins; Ubiquitin-Protein Ligases

alpha-Synuclein is a small cytosolic protein of presynaptic nerve terminals composed of seven 11-residue repeats and a hydrophilic tail. alpha-Synuclein misfolding and dysfunction may contribute to the pathogenesis of Parkinson's disease and neurodegenerative dementias, but its normal folding and function are unknown. In solution, alpha-synuclein is natively unstructured but assumes an alpha-helical conformation upon binding to phospholipid membranes. We now show that this conformation of alpha-synuclein consists of two alpha-helical regions that are interrupted by a short break. The structural organization of the alpha-helices of alpha-synuclein was not anticipated by sequence analyses and may be important for its pathogenic role.

Topics: alpha-Synuclein; Amino Acid Sequence; Detergents; Humans; Liposomes; Magnetic Resonance Spectroscopy; Nerve Tissue Proteins; Parkinsonian Disorders; Peptide Mapping; Phospholipids; Phosphoproteins; Protein Folding; Protein Structure, Secondary; Synucleins

Alpha-synuclein is likely to play a role in neurodegenerative processes, including the degeneration of nigrostriatal dopaminergic neurons that underlies Parkinson's disease. However, the toxicological properties of alpha-synuclein remain relatively unknown. Here, the relationship between alpha-synuclein expression and neuronal injury was studied in mice exposed to the herbicide paraquat. Paraquat neurotoxicity was compared in control animals versus mice with transgenic expression of human alpha-synuclein driven by the tyrosine hydroxylase (TH) promoter. In control mice, paraquat caused both the formation of alpha-synuclein-containing intraneuronal deposits and the degeneration of nigrostriatal neurons, as demonstrated by silver staining and a reduction of the counts of TH-positive and Nissl-stained cells. Mice overexpressing alpha-synuclein, either the human wild-type or the Ala53Thr mutant form of the protein, displayed paraquat-induced protein aggregates but were completely protected against neurodegeneration. These resistant animals were also characterized by increased levels of HSP70, a chaperone protein that has been shown to counteract paraquat toxicity in other experimental models and could therefore contribute to neuroprotection in alpha-synuclein transgenic mice. The results indicate a dissociation between toxicant-induced alpha-synuclein deposition and neurodegeneration. They support a role of alpha-synuclein against toxic insults and suggest that its involvement in human neurodegenerative processes may arise not only from a gain of toxic function, as previously proposed, but also from a loss of defensive properties.

Topics: alpha-Synuclein; Animals; Cell Count; Cell Survival; HSP70 Heat-Shock Proteins; Humans; Macromolecular Substances; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Paraquat; Parkinsonian Disorders; Promoter Regions, Genetic; Silver Staining; Substantia Nigra; Synucleins; Tyrosine 3-Monooxygenase

In humans, mutations in the alpha-synuclein gene or exposure to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produce Parkinson's disease with loss of dopaminergic neurons and depletion of nigrostriatal dopamine. alpha-Synuclein is a vertebrate-specific component of presynaptic nerve terminals that may function in modulating synaptic transmission. To test whether MPTP toxicity involves alpha-synuclein, we generated alpha-synuclein-deficient mice by homologous recombination, and analyzed the effect of deleting alpha-synuclein on MPTP toxicity using these knockout mice. In addition, we examined commercially available mice that contain a spontaneous loss of the alpha-synuclein gene. As described previously, deletion of alpha-synuclein had no significant effects on brain structure or composition. In particular, the levels of synaptic proteins were not altered, and the concentrations of dopamine, dopamine metabolites, and dopaminergic proteins were unchanged. Upon acute MPTP challenge, alpha-synuclein knockout mice were partly protected from chronic depletion of nigrostriatal dopamine when compared with littermates of the same genetic background, whereas mice carrying the spontaneous deletion of the alpha-synuclein gene exhibited no protection. Furthermore, alpha-synuclein knockout mice but not the mice with the alpha-synuclein gene deletion were slightly more sensitive to methamphetamine than littermate control mice. These results demonstrate that alpha-synuclein is not obligatorily coupled to MPTP sensitivity, but can influence MPTP toxicity on some genetic backgrounds, and illustrate the need for extensive controls in studies aimed at describing the effects of mouse knockouts on MPTP sensitivity.

Topics: 3,4-Dihydroxyphenylacetic Acid; Adrenergic Uptake Inhibitors; alpha-Synuclein; Animals; Antibodies; Blastomeres; Blotting, Southern; Corpus Striatum; Disease Models, Animal; DNA Primers; Dopamine; Dopamine Uptake Inhibitors; Dose-Response Relationship, Drug; Drug Interactions; Glutamic Acid; Hippocampus; Homovanillic Acid; Humans; Immunoblotting; Immunohistochemistry; Methamphetamine; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; MPTP Poisoning; Nerve Tissue Proteins; Neurons; Parkinsonian Disorders; Piperazines; Rats; Reserpine; Serotonin; Stem Cells; Subcellular Fractions; Substantia Nigra; Synucleins; Tyrosine 3-Monooxygenase

alpha-Synuclein accumulation plays an important role in the pathogenesis of Lewy body disease (LBD) and Parkinson's disease (PD). Although the mechanisms are not yet clear, it is possible that dysregulation of the extracellular signal-regulated kinase (ERK) might play a role. As caveolins form scaffolds onto which signaling molecules such as ERK can assemble, we propose that signaling alterations associated with alpha-synuclein accumulation and neurodegeneration, might be mediated via caveolae. Therefore, the objective of the present study was to investigate the potential contribution of alterations in the caveolar system in mediating alpha-synuclein effects on the ERK signaling pathway. For this, synuclein-transfected B103 neuroblastoma cells were used as a model system. In this cell line, caveolin-1 expression was up-regulated, whereas, ERK was down-regulated. ERK was weakly but consistently co-immunoprecipitated with alpha-synuclein but caveolin-1 did not co-immunoprecipitate with alpha-synuclein. Moreover, treatment of alpha-synuclein- overexpressing cells with caveolin-1 antisense oligonucleotides resulted in stimulation of ERK activity, with amelioration of the neuritic alterations. Transduction of alpha-synuclein-overexpressing cells, with an adenoviral vector directing the expression of ERK, resulted in suppression of caveolin-1 expression and re-establishment of the normal patterns of neurite outgrowth. These results suggest that alpha-synuclein may also interfere with ERK signaling by dysregulating caveolin-1 expression. Thus, the caveolin-1/ERK pathway could be a therapeutic target for the alpha-synuclein-related neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Caveolin 1; Caveolins; Cell Adhesion; Down-Regulation; Gene Expression; Mitogen-Activated Protein Kinases; Nerve Tissue Proteins; Neurites; Neuroblastoma; Neuronal Plasticity; Parkinson Disease; Parkinsonian Disorders; Rats; Signal Transduction; Synucleins; Transfection; Tumor Cells, Cultured; Up-Regulation

To determine if synucleinopathy pathology is related to REM sleep behavior disorder (RBD) plus dementia or parkinsonism.. The clinical and neuropathologic findings were analyzed on all autopsied cases evaluated at Mayo Clinic Rochester from January 1990 to April 2002 who were diagnosed with RBD and a neurodegenerative disorder. Ubiquitin and/or alpha-synuclein immunocytochemistry was used in all cases. The clinical and neuropathologic diagnoses were based on published criteria.. Fifteen cases were identified (14 men). All had clear histories of dream enactment behavior, and 10 had RBD confirmed by polysomnography. RBD preceded dementia or parkinsonism in 10 (66.7%) patients by a median of 10 (range 2 to 29) years. The clinical diagnoses included dementia with Lewy bodies (DLB) (n = 6); multiple-system atrophy (MSA) (n = 2); combined DLB, AD, and vascular dementia (n = 1); dementia (n = 1); dementia with parkinsonism (n = 1); PD (n = 1); PD with dementia (n = 1); dementia/parkinsonism/motor neuron disease (n = 1); and AD/Binswanger's disease (n = 1). The neuropathologic diagnoses were Lewy body disease (LBD) in 12 (neocortical in 11 and limbic in 1) and MSA in 3. Three also had argyrophilic grain pathology. In the LBD cases, concomitant AD pathology was present in six (one also with Binswanger's pathology, and one also with multiple subcortical infarcts).. In the setting of degenerative dementia or parkinsonism, RBD often reflects an underlying synucleinopathy.

Topics: Age of Onset; Aged; Aged, 80 and over; alpha-Synuclein; Dementia; Female; Humans; Male; Middle Aged; Nerve Tissue Proteins; Parkinsonian Disorders; REM Sleep Behavior Disorder; Retrospective Studies; Sex Factors; Synucleins

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder that usually manifests in the early sixth decade of life and progresses relentlessly with a mean survival of 9 years. Clinically, MSA is dominated by autonomic/urogenital failure, which may be associated with either levodopa (L-dopa) -unresponsive parkinsonism in 80% of cases (MSA-P subtype) or with cerebellar ataxia in 20% of cases (MSA-C subtype). Pathologically, MSA is characterized by a neuronal multisystem degeneration and abnormal glial cytoplasmic inclusions containing alpha-synuclein aggregates. Pharmacological treatment of motor features is disappointing except for a transient L-dopa response in a minority of MSA-P patients. In contrast, autonomic and urogenital features of MSA should be identified early on, because they can be treated effectively in many instances. Neuroprotective strategies are presently unavailable, however, two multicentre European trials have been launched to evaluate the effects of riluzole and human recombinant growth hormone on disease progression in MSA. Clearly, further randomised, controlled trials are required to identify effective symptomatic or neuroprotective agents in MSA. Several in vivo models have become available to allow a careful preselection of candidate agents. Several research groups have been formed in Europe (EMSA-SG, NNIPPS) and United States (NAMSA-SG), providing a framework for coordinated trial activity in MSA.

Topics: alpha-Synuclein; Animals; Brain; Clinical Trials as Topic; Humans; Inclusion Bodies; Levodopa; Multiple System Atrophy; Nerve Tissue Proteins; Neurologic Examination; Neurons; Neuroprotective Agents; Parkinsonian Disorders; Synucleins

Parkinson's disease is a movement disorder characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta. Dopaminergic neuronal loss also occurs in Drosophila melanogaster upon directed expression of alpha-synuclein, a protein implicated in the pathogenesis of Parkinson's disease and a major component of proteinaceous Lewy bodies. We report that directed expression of the molecular chaperone Hsp70 prevented dopaminergic neuronal loss associated with alpha-synuclein in Drosophila and that interference with endogenous chaperone activity accelerated alpha-synuclein toxicity. Furthermore, Lewy bodies in human postmortem tissue immunostained for molecular chaperones, also suggesting that chaperones may play a role in Parkinson's disease progression.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Brain Chemistry; Disease Models, Animal; Dopamine; Drosophila melanogaster; Drosophila Proteins; Female; Heat-Shock Proteins; HSC70 Heat-Shock Proteins; HSP40 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Humans; Inclusion Bodies; Lewy Bodies; Male; Nerve Degeneration; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; Parkinsonian Disorders; Synucleins; Transgenes

Familial diffuse Lewy body disease (DLBD) is rare and not yet associated with a defect in the synuclein gene. In the differential diagnosis of the parkinsonian syndromes, defects in vertical gaze tend to be identified with progressive supranuclear palsy. False-positive diagnosis of progressive supranuclear palsy can occur, and defects in vertical gaze have been reported in DLBD, although so far a pure vertical gaze palsy associated with pathological abnormalities in the substrate for vertical gaze has not been described.. To report the clinical and pathological findings in 2 siblings with DLBD, and to relate the distribution of the pathological abnormalities in the brainstem to centers for vertical gaze.. For several years, 2 Irish siblings experienced a progressive parkinsonism-dementia complex associated in one with a defect in vertical gaze and in both with visual hallucinations.. In both patients, results of pathological examination revealed (1) Lewy bodies positive for ubiquitin and alpha-synuclein together with cell loss and gliosis in the substantia nigra, locus ceruleus, and neocortex; and (2) similar findings in the rostral interstitial nucleus of the medial longitudinal fasciculus, the posterior commissure, and the interstitial nucleus of Cajal (substrates for vertical gaze).. Familial DLBD (not shown to be genetically as distinct from environmentally transmitted) has been shown to exist in an Irish family. Caution should be enjoined in the interpretation of defects in vertical gaze in the differential diagnosis of the parkinsonian syndromes.

Topics: Aged; alpha-Synuclein; Brain; Diagnosis, Differential; Eye Movements; Female; Humans; Lewy Body Disease; Male; Nerve Tissue Proteins; Parkinsonian Disorders; Synucleins; Tissue Distribution; Ubiquitin

Amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a progressive neurodegenerative disorder of Chamorro residents of Guam and the Mariana Islands, characterized by abundant neuron loss and tau neurofibrillary pathology similar to that observed in Alzheimer's disease (AD). A variety of neurodegenerative diseases with tau pathology including ALS/PDC also have alpha-synuclein positive pathology, primarily in the amygdala. We further characterized the tau and alpha-synuclein pathology in the amygdala of a large series of 30 Chamorros using immunohistochemical and biochemical techniques. Tau pathology was readily detected in both affected and unaffected Chamorros. In contrast, alpha-synuclein pathology was detected in 37% of patients with PDC but not detected in Chamorros without PDC or AD. The alpha-synuclein aggregates often co-localized within neurons harboring neurofibrillary tangles suggesting a possible interaction between the two proteins. Tau and alpha-synuclein pathology within the amygdala is biochemically similar to that observed in AD and synucleinopathies, respectively. Thus, the amygdala may be selectively vulnerable to developing both tau and alpha-synuclein pathology or tau pathology may predispose it to synuclein aggregation. Furthermore, in PDC, tau and alpha-synuclein pathology occurs independent of beta-amyloid deposition in amygdala thereby implicating the aggregation of these molecules in the severe neurodegeneration frequently observed in this location.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amygdala; Blotting, Western; Dementia; Female; Guam; Humans; Immunohistochemistry; Male; Middle Aged; Nerve Tissue Proteins; Neurofibrillary Tangles; Parkinsonian Disorders; Synucleins; tau Proteins

Several genetic errors in alpha-synuclein (Park1) and ubiquitin carboxyl-terminal-hydrolase L1(Park5) genes cause autosomal dominant familial Parkinson disease. Mutations in the parkin gene (Park2) are the major cause of autosomal recessive Parkinson disease.. To analyze the clinical and molecular data of 19 Spanish kindreds (13 with recessive, 4 with dominant, and 2 with uncertain inheritance) who have familial Parkinson disease.. We searched for the previously described mutations in Park1 and Park5 genes and for new or described mutations in Park2. We used single-strand conformation polymorphism, direct sequencing, and restriction digestion of polymerase chain reaction (PCR)-amplified genomic DNA for this study.. None of these families have either Park1 or Park5 mutations. We found 5 different mutations in Park2 gene in 5 of the families with recessive inheritance. To our knowledge, 2 of these mutations, V56E and C212Y, have not been previously reported. The other mutations found (deletion of exons 3 and 5 and 225delA) have been described in other ethnic groups. Heterozygous carriers of a single Park2 mutation either were asymptomatic or developed clinical symptoms in late adulthood or after brief exposure to haloperidol therapy.. Mutations in Park2 gene account for 38% of the families with recessive parkinsonism in Spain. We found 2 cases of simple heterozygous Park2 mutation carriers that developed clinical symptoms, either in late adulthood or after brief exposure to parkinsonizing agents. Thus, hereditary Parkinson disease has more variable clinical phenotype and molecular defects than previously thought since heterozygous mutations could be a risk factor for parkinsonism.

Topics: Adult; Aged; alpha-Synuclein; Amino Acid Substitution; Blotting, Southern; DNA Mutational Analysis; Female; Genetic Carrier Screening; Humans; Male; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Pedigree; Phenotype; Polymorphism, Single Nucleotide; Polymorphism, Single-Stranded Conformational; Spain; Synucleins; Thiolester Hydrolases; Ubiquitin Thiolesterase

Mutations in alpha-synuclein (A30P and A53T) are involved in some cases of familial Parkinson's disease (FPD), but it is not known how they result in nigral cell death. We examined the effect of alpha-synuclein overexpression on the response of cells to various insults. Wild-type alpha-synuclein and alpha-synuclein mutations associated with FPD were overexpressed in NT-2/D1 and SK-N-MC cells. Overexpression of wild-type alpha-synuclein delayed cell death induced by serum withdrawal or H(2)O(2), but did not delay cell death induced by 1-methyl-4-phenylpyridinium ion (MPP(+)). By contrast, wild-type alpha-synuclein transfectants were sensitive to viability loss induced by staurosporine, lactacystin or 4-hydroxy-2-trans-nonenal (HNE). Decreases in glutathione (GSH) levels were attenuated by wild-type alpha-synuclein after serum deprivation, but were aggravated following lactacystin or staurosporine treatment. Mutant alpha-synucleins increased levels of 8-hydroxyguanine, protein carbonyls, lipid peroxidation and 3-nitrotyrosine, and markedly accelerated cell death in response to all the insults examined. The decrease in GSH levels was enhanced in mutant alpha-synuclein transfectants. The loss of viability induced by toxic insults was by apoptosic mechanism. The presence of abnormal alpha-synucleins in substantia nigra in PD may increase neuronal vulnerability to a range of toxic agents.

Topics: 1-Methyl-4-phenylpyridinium; Aldehydes; alpha-Synuclein; Cell Division; Cell Line; Cell Survival; Clone Cells; Culture Media, Serum-Free; Enzyme Inhibitors; Gene Expression; Glutathione; Guanine; Humans; Hydrogen Peroxide; Ketones; Lipid Peroxidation; Mitochondria; Mutation; Nerve Tissue Proteins; Neuroblastoma; Oxidants; Oxidative Stress; Parkinsonian Disorders; Synucleins; Teratocarcinoma; Transfection; Tyrosine

Structural and functional alterations of alpha-synuclein is a presumed culprit in the demise of dopaminergic neurons in Parkinson's disease (PD). Alpha-synuclein mutations are found in familial but not in sporadic PD, raising the hypothesis that effects similar to those of familial PD-linked alpha-synuclein mutations may be achieved by oxidative post-translational modifications. Here, we show that wild-type alpha-synuclein is a selective target for nitration following peroxynitrite exposure of stably transfected HEK293 cells. Nitration of alpha-synuclein also occurs in the mouse striatum and ventral midbrain following administration of the parkinsonian neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Conversely, beta-synuclein and synaptophysin were not nitrated in MPTP-intoxicated mice. Our data demonstrate that alpha-synuclein is a target for tyrosine nitration, which, by disrupting its biophysical properties, may be relevant to the putative role of alpha-synuclein in the neurodegeneration associated with MPTP toxicity and with PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; beta-Synuclein; Cell Line; Corpus Striatum; Disease Models, Animal; Humans; Kidney; Male; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Oxidation-Reduction; Parkinsonian Disorders; Peroxynitrous Acid; Precipitin Tests; Protein Processing, Post-Translational; Synaptophysin; Synucleins; Transfection; Tyrosine

We describe an Australian family of Greek origin with a parkinsonian syndrome and an Ala53Thr alpha-synuclein gene mutation. Five of 9 siblings were affected, the average age of onset was 45 years, and the initial symptoms were variable, including resting tremor, bradykinesia, and gait disturbance, as previously described in families with the same point mutation. Affected family members responded well to levodopa, developed progressive cognitive impairment, and had a disease duration of 5 to 16 years. Pathologic features typical of idiopathic Parkinson's disease were found at autopsy. However, there were several additional features not previously reported in families with this gene mutation. These features included severe central hypoventilation, orthostatic hypotension, prominent myoclonus, and urinary incontinence. An abundance of alpha-synuclein-immunoreactive Lewy neurites were found in the brainstem pigmented nuclei, hippocampus, and temporal neocortex. The Lewy neurites were associated with temporal lobe vacuolation. Subcortical basal ganglia cell loss and gliosis were seen. These additional clinical and pathological features suggest that the Ala53Thr alpha-synuclein mutation can produce a more widespread disorder than found in typical idiopathic Parkinson's disease.

Topics: Adult; Age of Onset; alpha-Synuclein; Brain; Greece; Humans; Male; Middle Aged; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Synucleins

Environmental and genetic factors that contribute to the pathogenesis of Parkinson's disease are discussed. Mutations in the alpha-synuclein (alphaSYN ) gene are associated with rare cases of autosomal-dominant Parkinson's disease. We have analysed the dopaminergic system in transgenic mouse lines that expressed mutant [A30P]alphaSYN under the control of a neurone-specific Thy-1 or a tyrosine hydroxylase (TH) promoter. The latter mice showed somal and neuritic accumulation of transgenic [A30P]alphaSYN in TH-positive neurones in the substantia nigra. However, there was no difference in the number of TH-positive neurones in the substantia nigra and the concentrations of catecholamines in the striatum between these transgenic mice and non-transgenic littermates. To investigate whether forced expression of [A30P]alphaSYN increased the sensitivity to putative environmental factors we subjected transgenic mice to a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) regimen. The MPTP-induced decrease in the number of TH-positive neurones in the substantia nigra and the concentrations of catecholamines in the striatum did not differ in any of the [A30P]alphaSYN transgenic mouse lines compared with wild-type controls. These results suggest that mutations and forced expression of alphaSYN are not likely to increase the susceptibility to environmental toxins in vivo.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 3,4-Dihydroxyphenylacetic Acid; alpha-Synuclein; Amino Acid Substitution; Animals; Corpus Striatum; Dopamine; Homovanillic Acid; Humans; Mice; Mice, Transgenic; Nerve Tissue Proteins; Neurites; Neurons; Parkinson Disease; Parkinsonian Disorders; Promoter Regions, Genetic; Substantia Nigra; Synucleins; Thy-1 Antigens; Tyrosine 3-Monooxygenase

The authors identified the second known mutation in the alpha-synuclein(SNCA) gene, an alanine-to-proline exchange in amino acid position 30 (A30P), that cosegregates with the disease in one German family with autosomal dominantly inherited parkinsonism (ADP). The authors studied carriers of the A30P mutation to compare the phenotype of this mutation with idiopathic PD (IPD) and to assess nigrostriatal dopaminergic function in symptomatic and preclinical mutation carriers.. The pedigree of the A30P family spans five generations with five affected individuals. The authors performed detailed neurologic examinations followed by mutation analysis in 11 living individuals. In three mutation carriers, two individuals with definite PD and one person at risk for PD, they used L-[18]F-fluoro-3,4-dihydroxyphenylalanine (F-DOPA), [11]C-raclopride (RAC), and [18]F-fluorodeoxyglucose (FDG) PET to investigate presynaptic dopaminergic function, dopamine D2 receptors, and cerebral energy metabolism. The authors studied the cognitive functions of carriers of the A30P mutation using neuropsychological screening.. PET studies revealed striatal presynaptic dopaminergic alterations consistent with sporadic IPD in two affected family members and no evidence for nigrostriatal dopaminergic dysfunction in one presymptomatic mutation carrier. Neuropsychological testing in four mutation carriers provided evidence for cognitive impairment as a frequent and early symptom of the A30P mutation; this is also supported by regional cerebral energy metabolism alterations in the clinically presymptomatic subject.. The phenotype of the A30P mutation in the SNCA gene is similar to that of sporadic IPD, including a high variability of the age at disease onset, ranging from 54 to 76 years. The follow-up of presymptomatic carriers of the A30P mutation may give insight into preclinical disease stages and early manifestations of PD.

Topics: Aged; Alanine; alpha-Synuclein; Amino Acid Sequence; Apolipoproteins E; Brain; DNA Mutational Analysis; Female; Genotype; Germany; Humans; Male; Middle Aged; Mutation; Nerve Tissue Proteins; Neuropsychological Tests; Parkinsonian Disorders; Pedigree; Proline; Synucleins; Thiolester Hydrolases; Tomography, Emission-Computed; Ubiquitin Thiolesterase

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the progressive accumulation in selected neurons of protein inclusions containing alpha-synuclein and ubiquitin. Rare inherited forms of PD are caused by autosomal dominant mutations in alpha-synuclein or by autosomal recessive mutations in parkin, an E3 ubiquitin ligase. We hypothesized that these two gene products interact functionally, namely, that parkin ubiquitinates alpha-synuclein normally and that this process is altered in autosomal recessive PD. We have now identified a protein complex in normal human brain that includes parkin as the E3 ubiquitin ligase, UbcH7 as its associated E2 ubiquitin conjugating enzyme, and a new 22-kilodalton glycosylated form of alpha-synuclein (alphaSp22) as its substrate. In contrast to normal parkin, mutant parkin associated with autosomal recessive PD failed to bind alphaSp22. In an in vitro ubiquitination assay, alphaSp22 was modified by normal but not mutant parkin into polyubiquitinated, high molecular weight species. Accordingly, alphaSp22 accumulated in a non-ubiquitinated form in parkin-deficient PD brains. We conclude that alphaSp22 is a substrate for parkin's ubiquitin ligase activity in normal human brain and that loss of parkin function causes pathological alphaSp22 accumulation. These findings demonstrate a critical biochemical reaction between the two PD-linked gene products and suggest that this reaction underlies the accumulation of ubiquitinated alpha-synuclein in conventional PD.

Topics: alpha-Synuclein; Brain; Brain Stem; Cell Line; Detergents; Freezing; Glycosylation; Humans; Lewy Bodies; Ligases; Mutation, Missense; Nerve Tissue Proteins; Parkinson Disease; Parkinsonian Disorders; Substrate Specificity; Synucleins; Ubiquitin-Conjugating Enzymes; Ubiquitin-Protein Ligases; Ubiquitins

alpha-Synuclein has been identified as a major component of Lewy body inclusions, which are one of the pathologic hallmarks of idiopathic Parkinson's disease. Mutations in alpha-synuclein have been found to be responsible for rare familial cases of Parkinsonism. To test whether overexpression of human alpha-synuclein leads to inclusion formation and neuronal loss of dopaminergic cells in the substantia nigra, we made transgenic mice in which the expression of wild-type or mutant (A30P and A53T) human alpha-synuclein protein was driven by the promoter from the tyrosine hydroxylase gene. Even though high levels of human alpha-synuclein accumulated in dopaminergic cell bodies, Lewy-type-positive inclusions did not develop in the nigrostriatal system. In addition, the number of nigral neurons and the levels of striatal dopamine were unchanged relative to non-transgenic littermates, in mice up to one year of age. These findings suggest that overexpression of alpha-synuclein within nigrostriatal dopaminergic neurons is not in itself sufficient to cause aggregation into Lewy body-like inclusions, nor does it trigger overt neurodegenerative changes.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Humans; Lewy Bodies; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Nerve Tissue Proteins; Parkinsonian Disorders; Phenotype; Promoter Regions, Genetic; Substantia Nigra; Synucleins; Tyrosine 3-Monooxygenase

We examined whether autosomal dominant parkinsonism of a Japanese family, Sagamihara family, was due to the mutations of alpha-synuclein, parkin, tau, and UCH-L1, which have been reported as the causal genes for parkinsonism in other families. Restriction-enzyme digestion of polymerase-chain reaction (PCR) amplified genomic DNA fragments of alpha-synuclein exons 3 and 4 detected no point mutation. PCR-amplification of parkin exons 3, 4, 5, 6 and 7 detected no exon deletion. Direct sequencing of PCR-amplified DNA fragments of tau exons 9, 10, 12, and 13 and intron 10, and of UCH-L1 exon 4 revealed that all these exons and intron were normal including a polymorphic nucleotide substitution. These results indicated that the parkinsonism of the Sagamihara family seems not to be due to previously identified point mutations of alpha-synuclein, tau, or UCH-L1, or to exon deletion of parkin.

Topics: alpha-Synuclein; Exons; Female; Humans; Japan; Ligases; Male; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Pedigree; Polymerase Chain Reaction; Synucleins; tau Proteins; Thiolester Hydrolases; Ubiquitin Thiolesterase; Ubiquitin-Protein Ligases

Mutations in alpha-synuclein cause a form of familial Parkinson's disease (PD), and wild-type alpha-synuclein is a major component of the intraneuronal inclusions called Lewy bodies, a pathological hallmark of PD. These observations suggest a pathogenic role for alpha-synuclein in PD. Thus far, however, little is known about the importance of alpha-synuclein in the nigral dopaminergic pathway in either normal or pathological situations. Herein, we studied this question by assessing the expression of synuclein-1, the rodent homologue of human alpha-synuclein, in both normal and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. In normal mice, detectable levels of synuclein mRNA and protein were seen in all brain regions studied and especially in ventral midbrain. In the latter, there was a dense synuclein-positive nerve fiber network, which predominated over the substantia nigra, and only few scattered synuclein-positive neurons. After a regimen of MPTP that kills dopaminergic neurons by apoptosis, synuclein mRNA and protein levels were increased significantly in midbrain extracts; the time course of these changes paralleled that of MPTP-induced dopaminergic neurodegeneration. In these MPTP-injected mice, there was also a dramatic increase in the number of synuclein-immunoreactive neurons exclusively in the substantia nigra pars compacta; all synuclein-positive neurons were tyrosine hydroxylase-positive, but none coexpressed apoptotic features. These data indicate that synuclein is highly expressed in the nigrostriatal pathway of normal mice and that it is up-regulated following MPTP-induced injury. In light of the synuclein alterations, it can be suggested that, by targeting this protein, one may modulate MPTP neurotoxicity and, consequently, open new therapeutic avenues for PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Animals; Dopamine; Dopamine Agents; Male; Mesencephalon; Mice; Mice, Inbred C57BL; MPTP Poisoning; Nerve Tissue Proteins; Neurons; Parkinsonian Disorders; RNA, Messenger; Substantia Nigra; Synucleins; Tissue Distribution; Up-Regulation

We investigated by immunohistochemistry the deposition of alpha-synuclein in the brains of deceased patients with the parkinsonism-dementia complex (PDC) of Guam. Five of 13 PDC brains showed numerous alpha-synuclein positive neuronal inclusions and abnormal neurites, chiefly in the amygdala. Similar alpha-synuclein positive lesions were observed, although to a lesser extent, in the entorhinal cortex and the dorsal vagal nucleus. No alpha-synuclein positive inclusions were observed in motor cortex or locus coeruleus, and only a small number of positive inclusions were found in the Sommer's sector, temporal cortex, or substantia nigra. Some of the alpha-synuclein positive inclusions were reminiscent of cortical Lewy bodies (LB), but many of those in the amygdala coexisted with tau-positive pretangles and/or neurofibrillary tangles (NFT) within the same neurons. In these neurons, tau-positive shells encapsulated alpha-synuclein positive central cores or irregularly shaped alpha-synuclein-positive deposition intermingled with pretangles/NFT. Thus, the present study suggests that a common mechanism may govern aggregation of alpha-synuclein and tau in the amygdala, and that aggregation of alpha-synuclein may play some role in the neurodegenerative process of a tauopathy (i.e. PDC) in which Abeta deposition is virtually absent.

Topics: Adult; Aged; alpha-Synuclein; Amygdala; Amyotrophic Lateral Sclerosis; Dementia; Fluorescent Antibody Technique; Guam; Humans; Inclusion Bodies; Middle Aged; Nerve Tissue Proteins; Parkinsonian Disorders; Plaque, Amyloid; Synucleins; tau Proteins

The alpha-synuclein gene, which encodes a brain presynaptic nerve terminal protein of unknown function, is linked to familial early-onset Parkinson's disease (PD). The finding that alpha-synuclein forms the major fibrillary component of Lewy bodies in brains of PD patients suggests that the two point mutations in alpha-synuclein (Ala(53)Thr, Ala(30)Pro) may promote the aggregation of alpha-synuclein into filaments. To address the role of alpha-synuclein in neurodegenerative diseases, we performed a yeast two-hybrid screen of a rat adult brain cDNA library using rat alpha-synuclein 2 (alphaSYN2). Here we report that alphaSYN2 interacts specifically with Tat binding protein 1, a subunit of the 700-kDa proteasome activator (PA700), the regulatory complex of the 26S proteasome and of the modulator complex, which enhances PA700 activation of the proteasome.

Topics: alpha-Synuclein; Animals; ATPases Associated with Diverse Cellular Activities; Brain; Cell Line; Clone Cells; DNA-Binding Proteins; Dopamine; Humans; Kidney; Lewy Bodies; Macromolecular Substances; Nerve Tissue Proteins; Neurons; Parkinsonian Disorders; Peptide Hydrolases; Precipitin Tests; Presynaptic Terminals; Proteasome Endopeptidase Complex; Proteins; Rats; Saccharomyces; Synucleins; Transfection; Two-Hybrid System Techniques; Tyrosine 3-Monooxygenase

Topics: Adult; Aged; alpha-Synuclein; Chromosomes, Human, Pair 4; Family Health; Humans; Middle Aged; Mutation; Nerve Tissue Proteins; Parkinsonian Disorders; Russia; Synucleins