alpha-synuclein and Neurodegenerative-Diseases

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 neurodegenerative disease characterized by the progressive loss of dopaminergic neurons in the nigrostriatal pathway. Although the exact mechanisms underlying PD are still not completely understood, it is well accepted that α-synuclein plays key pathophysiological roles as the main constituent of the cytoplasmic inclusions known as Lewy bodies. Several post-translational modifications (PTMs), such as the best-known phosphorylation, target α-synuclein and are thus implicated in its physiological and pathological functions. In this review, we present (1) an overview of the pathophysiological roles of α-synuclein, (2) a descriptive analysis of α-synuclein PTMs, including phosphorylation, ubiquitination, SUMOylation, acetylation, glycation, truncation, and O-GlcNAcylation, as well as (3) a brief summary on α-synuclein PTMs as potential biomarkers for PD. A better understanding of α-synuclein PTMs is of paramount importance for elucidating the mechanisms underlying PD and can thus be expected to improve early detection and monitoring disease progression, as well as identify promising new therapeutic targets.

Topics: alpha-Synuclein; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease; Protein Processing, Post-Translational

Parkinson's disease (PD) is a common chronic neurodegenerative disease, and the heat shock proteins (HSPs) are proved to be of great value for PD. In addition, HSPs can maintain protein homeostasis, degrade and inhibit protein aggregation by properly folding and activating intracellular proteins in PD. This study mainly summarizes the important roles of HSPs in PD and explores their feasibility as targets. We introduced the structural and functional characteristics of HSPs and the physiological functions of HSPs in PD. HSPs can protect neurons from damage by degrading aggregates with three mechanisms, including the aggregation and removing α-Synuclein (α-Syn) aggregates, promotion the autophagy of abnormal proteins, and inhibition the apoptosis of degenerated neurons. This study underscores the importance of HSPs as targets in PD and helps to expand new mechanisms in PD treatment strategies.

Topics: alpha-Synuclein; Heat-Shock Proteins; Humans; Neurodegenerative Diseases; Neurons; Parkinson Disease; Protein Aggregates

Parkinson's disease (PD) is the world's second primary neurodegenerative disease, and the diagnosis and treatment of PD have become mainstream research. Over the past decades, several studies have identified potential biomarkers for diagnosing PD. Among them, extracellular vesicles (EVs) can carry specific biomarkers reflecting the physiological and pathological state of the body. Due to the blood-brain barrier (BBB) limitation, peripheral blood is limited in diagnosing neurodegenerative diseases. With the increasing research on EVs, their ability to pass through BBB indicated that peripheral blood could depict disease status like cerebrospinal fluid (CSF). Peripheral blood is a clinically available sample and has recently been widely used by researchers in various studies. In this review, we summarized previous studies on PD diagnosis biomarkers in peripheral blood EVs and evaluated their diagnostic value. Some EV surface markers were also described, which can extract EVs from specific cell origins. In addition, the combination of several biomarkers demonstrated good diagnostic performance in PD diagnosis compared with a single biomarker, suggesting the focus of future research.

Topics: alpha-Synuclein; Biomarkers; Blood-Brain Barrier; Extracellular Vesicles; Humans; Neurodegenerative Diseases; Parkinson Disease

The protein dyshomeostasis is identified as the hallmark of many age-related neurodegenerative disorders including Parkinson's disease (PD). The diseased brain shows the deposition of Lewy bodies composed of α-synuclein protein aggregates. Functional proteostasis is characterized by the well-coordinated signaling network constituting unfolded protein response (UPR), the ubiquitin-proteasome system (UPS), and the autophagy-lysosome pathway (ALP). These networks ensure proper synthesis, folding, confirmation, and degradation of protein i.e., α-synuclein protein in PD. The proper functioning the of intricately woven proteostasis network is quite resilient to sustain under the influence of stressors. The synuclein protein turnover is hugely influenced by the autosomal dominant, recessive, and X-linked mutational changes of a gene involved in UPR, UPS, and ALP. The methylation, acetylation-related epigenetic modifications of DNA and histone proteins along with microRNA-mediated transcriptional changes also lead to extensive proteostasis dysregulation. The result of defective proteostasis is the deposition of many proteins which start appearing in the biofluids and can be identified as potential biomarkers for early diagnosis of PD. The therapeutic intervention targeted at different strata of proteostasis machinery holds great possibilities for delaying the age-related accumulation of pathological hallmarks.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease; Proteasome Endopeptidase Complex; Proteostasis; Ubiquitin; Unfolded Protein Response

Parkinson's disease (PD) is a neurodegenerative disease characterized by the accumulation of alpha-synuclein (aSyn) in the nigrostriatal pathway that is followed by severe neuroinflammatory response. PD etiology is still puzzling; however, the mitocentric view might explain the vast majority of molecular findings not only in the brain, but also at systemic level. While neuronal degeneration is tightly associated with mitochondrial dysfunction, the causal role between aSyn accumulation and mitochondrial dysfunction still requires further investigation. Moreover, mitochondrial dysfunction can elicit an inflammatory response that may be transmitted locally but also in a long range through systemic circulation. Furthermore, mitochondrial-driven innate immune activation may involve the synthesis of antimicrobial peptides, of which aSyn poses as a good candidate. While there is still a need to clarify disease-elicited mechanisms and how aSyn has the ability to modulate mitochondrial and cellular dysfunction, recent studies provide insightful views on mitochondria-inflammation axis in PD etiology.

Topics: alpha-Synuclein; Brain; Humans; Immunity, Innate; Inflammation; Mitochondria; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease, and is characterized by accumulation of α-synuclein (α-syn). Neuroinflammation driven by microglia is an important pathological manifestation of PD. α-Syn is a crucial marker of PD, and its accumulation leads to microglia M1-like phenotype polarization, activation of NLRP3 inflammasomes, and impaired autophagy and phagocytosis in microglia. Autophagy of microglia is related to degradation of α-syn and NLRP3 inflammasome blockage to relieve neuroinflammation. Microglial autophagy and phagocytosis of released α-syn or fragments from apoptotic neurons maintain homeostasis in the brain. A variety of PD-related genes such as LRRK2, GBA and DJ-1 also contribute to this stability process.. Further studies are needed to determine how α-syn works in microglia.. A keyword-based search was performed using the PubMed database for published articles.. In this review, we discuss the interaction between microglia and α-syn in PD pathogenesis and the possible mechanism of microglial autophagy and phagocytosis in α-syn clearance and inhibition of neuroinflammation. This may provide a novel insight into treatment of PD.

Topics: alpha-Synuclein; Autophagy; Humans; Inflammasomes; Microglia; Neurodegenerative Diseases; Neuroinflammatory Diseases; NLR Family, Pyrin Domain-Containing 3 Protein; Parkinson Disease; Phagocytosis

Parkinson's disease is a health-threatening neurodegenerative disease of the elderly with clinical manifestations of motor and non-motor deficits such as tremor palsy and loss of smell. Alpha-synuclein (α-Syn) is the pathological basis of PD, it can abnormally aggregate into insoluble forms such as oligomers, fibrils, and plaques, causing degeneration of nigrostriatal dopaminergic neurons in the substantia nigra in the patient's brain and the formation of Lewy bodies (LBs) and Lewy neuritis (LN) inclusions. As a result, achieving α-Syn aggregate detection in the early stages of PD can effectively stop or delay the progression of the disease. In this paper, we provide a brief overview and analysis of the molecular structures and α-Syn in vivo and in vitro detection methods, such as mass spectrometry, antigen-antibody recognition, electrochemical sensors, and imaging techniques, intending to provide more technological support for detecting α-Syn early in the disease and intervening in the progression of Parkinson's disease.

Topics: Aged; alpha-Synuclein; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease; Tremor

Parkinson's disease (PD) is the most common neurodegenerative movement disorder. There are no available therapeutics that slow or halt the progressive loss of dopamine-producing neurons, which underlies the primary clinical symptoms. Currently approved PD drugs can provide symptomatic relief by increasing brain dopamine content or activity; however, the alleviation is temporary, and the effectiveness diminishes with the inevitable progression of neurodegeneration. Discovery and development of disease-modifying neuroprotective therapies has been hampered by insufficient understanding of the root cause of PD-related neurodegeneration. The etiology of PD involves a combination of genetic and environmental factors. Although a single cause has yet to emerge, genetic, cell biological and neuropathological evidence implicates mitochondrial dysfunction and protein aggregation. Postmortem PD brains show pathognomonic Lewy body intraneuronal inclusions composed of aggregated α-synuclein, indicative of failure to degrade misfolded protein. Mutations in the genes that code for α-synuclein, as well as the E3 ubiquitin ligase Parkin, cause rare inherited forms of PD. While many ubiquitin ligases label proteins with ubiquitin chains to mark proteins for degradation by the proteasome, Parkin has been shown to mark dysfunctional mitochondria for degradation by mitophagy. The ubiquitin proteasome system participates in several aspects of the cell's response to mitochondrial damage, affording numerous therapeutic opportunities to augment mitophagy and potentially stop PD progression. This review examines the role and therapeutic potential of such UPS modulators, exemplified by both ubiquitinating and deubiquitinating enzymes.

Topics: alpha-Synuclein; Dopamine; Humans; Neurodegenerative Diseases; Parkinson Disease; Proteasome Endopeptidase Complex; Ubiquitin; Ubiquitin-Protein Ligases

The clinicopathologic model that defines neurodegenerative disorders has remained unchanged for over a century. According to it, clinical manifestations are defined and explained by a given pathology, that is, by the burden and distribution of selected proteins aggregated into insoluble amyloids. There are two logical consequences from this model: (1) a measurement of the disease-defining pathology represents a biomarker of that disease in everyone affected, and (2) the targeted elimination of that pathology should end that disease. But success in disease modification guided by this model has remained elusive. New technologies to probe living biology have been used to validate rather than question the clinicopathologic model, despite three important observations: (1) a disease-defining pathology in isolation (without other pathologies) is an exceptional autopsy finding; (2) many genetic and molecular pathways converge on the same pathology; (3) the presence of pathology without neurological disease is more common than expected by chance. We here discuss the rationale for abandoning the clinicopathologic model, review the competing biological model of neurodegeneration, and propose developmental pathways for biomarker development and disease-modifying efforts. Further, in justifying future disease-modifying trials testing putative neuroprotective molecules, a key inclusion criterion must be the deployment of a bioassay of the mechanism corrected by the therapy of interest. No improvements in trial design or execution can overcome the fundamental deficit created by testing experimental therapies in clinically defined recipients unselected for their biologically suitability. Biological subtyping is the key developmental milestone needed to launch precision medicine for patients living with neurodegenerative disorders.

Topics: alpha-Synuclein; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease; Precision Medicine

Parkinson's disease (PD) is a multifarious neurodegenerative disease. Its pathology is characterized by a prominent early death of dopaminergic neurons in the pars compacta of the substantia nigra and the presence of Lewy bodies with aggregated α-synuclein. Although the α-synuclein pathological aggregation and propagation, induced by several factors, is considered one of the most relevant hypotheses, PD pathogenesis is still a matter of debate. Indeed, environmental factors and genetic predisposition play an important role in PD. Mutations associated with a high risk for PD, usually called monogenic PD, underlie 5% to 10% of all PD cases. However, this percentage tends to increase over time because of the continuous identification of new genes associated with PD. The identification of genetic variants that can cause or increase the risk of PD has also given researchers the possibility to explore new personalized therapies. In this narrative review, we discuss the recent advances in the treatment of genetic forms of PD, focusing on different pathophysiologic aspects and ongoing clinical trials.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease; Substantia Nigra; Synucleinopathies

Alpha-Synuclein (α-Syn) is one of the most important molecules involved in the pathogenesis of Parkinson's disease and related disorders, synucleinopathies, but also in several other neurodegenerative disorders with a more elusive role. This review analyzes the activities of α-Syn, in different conformational states, monomeric, oligomeric and fibrils, in relation to neuronal dysfunction. The neuronal damage induced by α-Syn in various conformers will be analyzed in relation to its capacity to spread the intracellular aggregation seeds with a prion-like mechanism. In view of the prominent role of inflammation in virtually all neurodegenerative disorders, the activity of α-Syn will also be illustrated considering its influence on glial reactivity. We and others have described the interaction between general inflammation and cerebral dysfunctional activity of α-Syn. Differences in microglia and astrocyte activation have also been observed when in vivo the presence of α-Syn oligomers has been combined with a lasting peripheral inflammatory effect. The reactivity of microglia was amplified, while astrocytes were damaged by the double stimulus, opening new perspectives for the control of inflammation in synucleinopathies. Starting from our studies in experimental models, we extended the perspective to find useful pointers to orient future research and potential therapeutic strategies in neurodegenerative disorders.

Topics: alpha-Synuclein; Humans; Inflammation; Neurodegenerative Diseases; Parkinson Disease; Synucleinopathies

Parkinson's disease (PD) is a progressive neurodegenerative disorder clinically defined by motor instability, bradykinesia, and resting tremors. The clinical symptomatology is seen alongside pathologic changes, most notably the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the accumulation of α-synuclein and neuromelanin aggregates throughout numerous neural circuits. Traumatic brain injury (TBI) has been implicated as a risk factor for developing various neurodegenerative diseases, with the most compelling argument for the development of PD. Dopaminergic abnormalities, the accumulation of α-synuclein, and disruptions in neural homeostatic mechanisms, including but not limited to the release of pro-inflammatory mediators and the production of reactive oxygen species (ROS), are all present following TBI and are closely related to the pathologic changes seen in PD. Neuronal iron accumulation is discernable in degenerative and injured brain states, as is aquaporin-4 (APQ4). APQ4 is an essential mediator of synaptic plasticity in PD and regulates edematous states in the brain after TBI. Whether the cellular and parenchymal changes seen post-TBI directly cause neurodegenerative diseases such as PD is a point of considerable interest and debate; this review explores the vast array of neuroimmunological interactions and subsequent analogous changes that occur in TBI and PD. There is significant interest in exploring the validity of the relationship between TBI and PD, which is a focus of this review.

Topics: alpha-Synuclein; Brain Injuries, Traumatic; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Neuroimmunomodulation; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease, and its prevalence is increasing with age. A wealth of genetic evidence indicates that the endo-lysosomal system is a major pathway driving PD pathogenesis with a growing number of genes encoding endo-lysosomal proteins identified as risk factors for PD, making it a promising target for therapeutic intervention. However, detailed knowledge and understanding of the molecular mechanisms linking these genes to the disease are available for only a handful of them (e.g. LRRK2, GBA1, VPS35). Taking on the challenge of studying poorly characterized genes and proteins can be daunting, due to the limited availability of tools and knowledge from previous literature. This review aims at providing a valuable source of molecular and cellular insights into the biology of lesser-studied PD-linked endo-lysosomal genes, to help and encourage researchers in filling the knowledge gap around these less popular genetic players. Specific endo-lysosomal pathways discussed range from endocytosis, sorting, and vesicular trafficking to the regulation of membrane lipids of these membrane-bound organelles and the specific enzymatic activities they contain. We also provide perspectives on future challenges that the community needs to tackle and propose approaches to move forward in our understanding of these poorly studied endo-lysosomal genes. This will help harness their potential in designing innovative and efficient treatments to ultimately re-establish neuronal homeostasis in PD but also other diseases involving endo-lysosomal dysfunction.

Topics: alpha-Synuclein; Endocytosis; Endosomes; Humans; Lysosomes; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. Inflammation has been observed in both the idiopathic and familial forms of PD. Importantly, PD is reported more often in men than in women, men having at least 1.5- fold higher risk to develop PD than women. This review summarizes the impact of biological sex and sex hormones on the neuroimmune contributions to PD and its investigation in animal models of PD. Innate and peripheral immune systems participate in the brain neuroinflammation of PD patients and is reproduced in neurotoxin, genetic and α-synuclein based models of PD. Microglia and astrocytes are the main cells of the innate immune system in the central nervous system and are the first to react to restore homeostasis in the brain. Analysis of serum immunoprofiles in female and male control and PD patients show that a great proportion of these markers differ between males and females. The relationship between cerebrospinal fluid inflammatory markers and PD clinical characteristics or PD biomarkers shows sex differences. Conversely, in animal models of PD, sex differences in inflammation are well documented and the beneficial effects of endogenous and exogenous estrogenic modulation in inflammation have been reported. Targeting neuroinflammation in PD is an emerging therapeutic option but gonadal drugs have not yet been investigated in this respect, thus offering new opportunities for sex specific treatments.

Topics: alpha-Synuclein; Animals; Brain; Female; Inflammation; Male; Microglia; Neurodegenerative Diseases; Neuroinflammatory Diseases; Parkinson Disease

Parkinson's disease (PD) is characterized by fibrillation of disordered proteins known as Lewy bodies in the substantia nigra that also undergo progressive neurodegeneration. The aggregation of α-synuclein (α-syn) is a hallmark and potentially a critical step in the development of Parkinson's disease and other synucleinopathies. The synaptic vesicle protein α-syn is a small, abundant, highly conserved disordered protein and the causative agent of neurodegenerative diseases. Several novel pharmacologically active compounds are used to treat PD and other neurodegenerative disorders. Though, the mechanism through which these molecules inhibit the α-syn aggregation is still not fully understood.. This review article is focused on the recent advancements in compounds that can inhibit the development of α-syn fibrillation and oligomerization.. The current review article is based on the most recent and frequently cited papers from Google Scholar, SciFinder, and Researchgate sources.. In the progression of PD, the mechanism of α-syn aggregation involves the structural transformation from monomers into amyloid fibrils. As the accumulation of α-syn in the brain has been linked to many disorders, the recent search for disease-modifying medications mainly focused on modifying the α-syn aggregation. This review contains a detailed report of literature findings and illustrates the unique structural features, structure-activity relationship, and therapeutic potential of the natural flavonoids in the inhibition of α-syn are also discussed.. Recently, many naturally occurring molecules such as curcumin, polyphenols, nicotine, EGCG, and stilbene have been recognized to inhibit the fibrillation and toxicity of α-syn. Therefore, knowing the α-synuclein filament's structure and how they originate will help invent particular biomarkers for synucleinopathies and develop reliable and effective mechanism-based therapeutics. We hope the information this review provides may help evaluate novel chemical compounds, such as α- syn aggregation inhibitors, and will contribute to developing novel drugs for treating Parkinson's disease.

Topics: alpha-Synuclein; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease; Synucleinopathies

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease (AD). Genetic predisposition and immune dysfunction are involved in the pathogenesis of PD. Notably, peripheral inflammatory disorders and neuroinflammation are associated with PD neuropathology. Type 2 diabetes mellitus (T2DM) is associated with inflammatory disorders due to hyperglycaemia-induced oxidative stress and the release of pro-inflammatory cytokines. Particularly, insulin resistance (IR) in T2DM promotes the degeneration of dopaminergic neurons in the substantia nigra (SN). Thus, T2DM-induced inflammatory disorders predispose to the development and progression of PD, and their targeting may reduce PD risk in T2DM. Therefore, this narrative review aims to find the potential link between T2DM and PD by investigating the role of inflammatory signalling pathways, mainly the nuclear factor kappa B (NF-κB) and the nod-like receptor pyrin 3 (NLRP3) inflammasome. NF-κB is implicated in the pathogenesis of T2DM, and activation of NF-κB with induction of neuronal apoptosis was also confirmed in PD patients. Systemic activation of NLRP3 inflammasome promotes the accumulation of α-synuclein and degeneration of dopaminergic neurons in the SN. Increasing α-synuclein in PD patients enhances NLRP3 inflammasome activation and the release of interleukin (IL)-1β followed by the development of systemic inflammation and neuroinflammation. In conclusion, activation of the NF-κB/NLRP3 inflammasome axis in T2DM patients could be the causal pathway in the development of PD. The inflammatory mechanisms triggered by activated NLRP3 inflammasome lead to pancreatic β-cell dysfunction and the development of T2DM. Therefore, attenuation of inflammatory changes by inhibiting the NF-κB/NLRP3 inflammasome axis in the early T2DM may reduce future PD risk.

Topics: alpha-Synuclein; Diabetes Mellitus, Type 2; Humans; Inflammasomes; Neurodegenerative Diseases; Neuroinflammatory Diseases; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; NLR Proteins; Parkinson Disease; Pyrin

Parkinson's disease is a neurodegenerative disease affecting mainly the elderly population. It is characterized by the loss of dopaminergic neurons of the substantia nigra pars compacta region. Parkinson's disease patients exhibit motor symptoms like tremors, rigidity, bradykinesia/hypokinesia, and non-motor symptoms like depression, cognitive decline, delusion, and pain. Major pathophysiological factors which contribute to neuron loss include excess/misfolded alpha-synuclein aggregates, microglial cell-mediated neuroinflammation, excitotoxicity, oxidative stress, and defective mitochondrial function. Sigma-1 receptors are molecular chaperones located at mitochondria-associated ER membrane. Their activation (by endogenous ligands or agonists) has shown neuroprotective and neurorestorative effects in various diseases. This review discusses the roles of activated Sig-1 receptors in modulating various pathophysiological features of Parkinson's disease like alpha-synuclein aggregates, neuroinflammation, excitotoxicity, and oxidative stress.

Topics: Aged; alpha-Synuclein; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Neuroinflammatory Diseases; Parkinson Disease; Sigma-1 Receptor; Substantia Nigra

Endocytosis is the fundamental uptake process through which cells internalize extracellular materials and species. Neurodegenerative diseases (NDs) are characterized by a progressive accumulation of intrinsically disordered protein species, leading to neuronal death. Misfolding in many proteins leads to various NDs such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and other disorders. Despite the significance of disordered protein species in neurodegeneration, their spread between cells and the cellular uptake of extracellular species is not entirely understood. This review discusses the major internalization mechanisms of the different conformer species of these proteins and their endocytic mechanisms. We briefly introduce the broad types of endocytic mechanisms found in cells and then summarize what is known about the endocytosis of monomeric, oligomeric and aggregated conformations of tau, Aβ, α-Syn, Huntingtin, Prions, SOD1, TDP-43 and other proteins associated with neurodegeneration. We also highlight the key players involved in internalizing these disordered proteins and the several techniques and approaches to identify their endocytic mechanisms. Finally, we discuss the obstacles involved in studying the endocytosis of these protein species and the need to develop better techniques to elucidate the uptake mechanisms of a particular disordered protein species.

Topics: alpha-Synuclein; Alzheimer Disease; Humans; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregates

Parkinson's disease (PD) is an incurable neurodegenerative disease that is rarely diagnosed at an early stage. Although the understanding of PD-related mechanisms has greatly improved over the last decade, the diagnosis of PD is still based on neurological examination through the identification of motor symptoms, including bradykinesia, rigidity, postural instability, and resting tremor. The early phase of PD is characterized by subtle symptoms with a misdiagnosis rate of approximately 16-20%. The difficulty in recognizing early PD has implications for the potential use of novel therapeutic approaches. For this reason, it is important to discover PD brain biomarkers that can indicate early dopaminergic dysfunction through their changes in body fluids, such as saliva, urine, blood, or cerebrospinal fluid (CSF). For the CFS-based test, the invasiveness of sampling is a major limitation, whereas the other body fluids are easier to obtain and could also allow population screening. Following the identification of the crucial role of alpha-synuclein (α-syn) in the pathology of PD, a very large number of studies have summarized its changes in body fluids. However, methodological problems have led to the poor diagnostic/prognostic value of this protein and alternative biomarkers are currently being investigated. The aim of this paper is therefore to summarize studies on protein biomarkers that are alternatives to α-syn, particularly those that change in nigrostriatal areas and in biofluids, with a focus on blood, and, eventually, saliva and urine.

Topics: alpha-Synuclein; Biomarkers; Body Fluids; Brain; Humans; Neurodegenerative Diseases; Parkinson Disease

Inflammatory mechanisms are increasingly recognized as important contributors to the pathogenesis of neurodegenerative diseases, including Lewy body dementia (LBD). Our objectives were to, firstly, review inflammation investigation methods in LBD (dementia with Lewy bodies and Parkinson's disease dementia) and, secondly, identify alterations in inflammatory signals in LBD compared to people without neurodegenerative disease and other neurodegenerative diseases. A systematic scoping review was performed by searching major electronic databases (MEDLINE, Embase, Web of Science, and PSYCHInfo) to identify relevant human studies. Of the 2509 results screened, 80 studies were included. Thirty-six studies analyzed postmortem brain tissue, and 44 investigated living subjects with cerebrospinal fluid, blood, and/or brain imaging assessments. Largely cross-sectional data were available, although two longitudinal clinical studies investigated prodromal Lewy body disease. Investigations were focused on inflammatory immune cell activity (microglia, astrocytes, and lymphocytes) and inflammatory molecules (cytokines, etc.). Results of the included studies identified innate and adaptive immune system contributions to inflammation associated with Lewy body pathology and clinical disease features. Different signals in early and late-stage disease, with possible late immune senescence and dystrophic glial cell populations, were identified. The strength of these associations is limited by the varying methodologies, small study sizes, and cross-sectional nature of the data. Longitudinal studies investigating associations with clinical and other biomarker outcomes are needed to improve understanding of inflammatory activity over the course of LBD. This could identify markers of disease activity and support therapeutic development.

Topics: alpha-Synuclein; Cross-Sectional Studies; Dementia; Humans; Inflammation; Lewy Body Disease; Neurodegenerative Diseases; Parkinson Disease

Abnormal assembly of tau, α-synuclein, TDP-43 and amyloid-β proteins into amyloid filaments defines most human neurodegenerative diseases. Genetics provides a direct link between filament formation and the causes of disease. Developments in cryo-electron microscopy (cryo-EM) have made it possible to determine the atomic structures of amyloids from postmortem human brains. Here we review the structures of brain-derived amyloid filaments that have been determined so far and discuss their impact on research into neurodegeneration. Whereas a given protein can adopt many different filament structures, specific amyloid folds define distinct diseases. Amyloid structures thus provide a description of neuropathology at the atomic level and a basis for studying disease. Future research should focus on model systems that replicate the structures observed in disease to better understand the molecular mechanisms of disease and develop improved diagnostics and therapies.

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Cryoelectron Microscopy; Humans; Neurodegenerative Diseases; Pathology, Molecular; Protein Folding

Parkinson's disease (PD) is an aging-associated neurodegenerative disorder with the hallmark of abnormal aggregates of alpha-synuclein (α-syn) in Lewy bodies (LBs) and Lewy neurites (LNs). Currently, pathogenic α-syn and mitochondrial dysfunction have been considered as prominent roles that give impetus to the PD onset. This review describes the α-syn pathology and mitochondrial alterations in PD, and focuses on how α-syn interacts with multiple aspects of mitochondrial homeostasis in the pathogenesis of PD.

Topics: alpha-Synuclein; Humans; Lewy Bodies; Mitochondria; Neurodegenerative Diseases; Parkinson Disease

The small neuronal protein α-synuclein (αS) is found in pre-synaptic terminals and plays a role in vesicle recycling and neurotransmission. Fibrillar aggregates of αS are the hallmark of Parkinson's disease and related neurodegenerative disorders. In both health and disease, interactions with lipids influence αS's structure and function, prompting much study of the effects of lipids on αS aggregation. A comprehensive collection (126 examples) of aggregation rate data for various αS/lipid combinations was presented, including combinations of lipid variations and mutations or post-translational modifications of αS. These data were interpreted in terms of lipid structure to identify general trends. These tabulated data serve as a resource for the community to help in the interpretation of aggregation experiments with lipids and to be potentially used as inputs for computational models of lipid effects on aggregation.

Topics: alpha-Synuclein; Humans; Lipids; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder and the fastest growing neurologic disease in the world, yet no disease-modifying therapy is available for this disabling condition. Multiple lines of evidence implicate the protein

Topics: alpha-Synuclein; Brain; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease

The vast majority of neurodegenerative diseases are associated with an accumulation of undegraded and aggregated proteins. Hence the word proteinopathies is now used to refer to these neurodegenerative diseases. The synucleinopathies are one component of them, in particular in Parkinson's disease. The neuropathological features of Parkinson's disease are the progressive loss of dopamine neurons in the midbrain and the formation of aggregates composed mainly of a-synuclein protein. Experimental evidence suggests that under pathological conditions, normal soluble a-synuclein protein adopts an abnormal folding and subsequently aggregates, with a propensity to spread throughout the central nervous system. This review article discusses the specifics of a-synuclein aggregation and emerging mechanisms for understanding its spread and aims at providing a molecular explanation for the progression of the disease in humans.. Maladie de Parkinson - Le rôle de la synucléine.. La vaste majorité des maladies neurodégénératives sont associées à une accumulation de protéines non dégradées et agrégées. On appelle ainsi ces maladies, protéinopathies. Les synucléinopathies en sont une des composantes, en particulier la maladie de Parkinson. Les caractéristiques neuropathologiques de la maladie de Parkinson comprennent la perte progressive de neurones dopaminergiques du mésencéphale et la formation d’agrégats protéiques, constitués notamment de la protéine a-synucléine. Des preuves expérimentales suggèrent que dans des conditions pathologiques, cette protéine, normalement soluble, adopte un repliement anormal et s’agrège, avec une propension à se propager dans tout le système nerveux central. Dans cette Synthèse, nous discuterons des spécificités de l’agrégation de l’a-synucléine et de ses mécanismes, qui permettent désormais de comprendre sa propagation et fournissent une explication moléculaire à la progression de la maladie chez l’homme.

Topics: alpha-Synuclein; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Parkinson Disease

Lysosomes are ubiquitous organelles with a fundamental role in maintaining cellular homeostasis by mediating degradation and recycling processes. Cathepsins are the most abundant lysosomal hydrolyses and are responsible for the bulk degradation of various substrates. A correct autophagic function is essential for neuronal survival, as most neurons are post-mitotic and thus susceptible to accumulate cellular components. Increasing evidence suggests a crucial role of the lysosome in neurodegeneration as a key regulator of aggregation-prone and disease-associated proteins, such as α-synuclein, β-amyloid and huntingtin. Particularly, alterations in lysosomal cathepsins CTSD, CTSB and CTSL can contribute to the pathogenesis of neurodegenerative diseases as seen for neuronal ceroid lipofuscinosis, synucleinopathies (Parkinson's disease, Dementia with Lewy Body and Multiple System Atrophy) as well as Alzheimer's and Huntington's disease. In this review, we provide an overview of recent evidence implicating CTSD, CTSB and CTSL in neurodegeneration, with a special focus on the role of these enzymes in α-synuclein metabolism. In addition, we summarize the potential role of lysosomal cathepsins as clinical biomarkers in neurodegenerative diseases and discuss potential therapeutic approaches by targeting lysosomal function.

Topics: alpha-Synuclein; Brain; Cathepsins; Humans; Lysosomes; Neurodegenerative Diseases

Protein misfolding is a general hallmark of protein deposition diseases, such as Alzheimer's disease or Parkinson's disease, in which different types of aggregated species (oligomers, protofibrils and fibrils) are generated by the cells. Despite widespread interest, the relationship between oligomers and fibrils in the aggregation process and spreading remains elusive. A large variety of experimental evidences supported the idea that soluble oligomeric species of different proteins might be more toxic than the larger fibrillar forms. Furthermore, the lack of correlation between the presence of the typical pathological inclusions and disease sustained this debate. However, recent data show that the β-sheet core of the α-Synuclein (αSyn) fibrils is unable to establish persistent interactions with the lipid bilayers, but they can release oligomeric species responsible for an immediate dysfunction of the recipient neurons. Reversibly, such oligomeric species could also contribute to pathogenesis via neuron-to-neuron spreading by their direct cell-to-cell transfer or by generating new fibrils, following their neuronal uptake. In this Review, we discuss the various mechanisms of cellular dysfunction caused by αSyn, including oligomer toxicity, fibril toxicity and fibril spreading.

Topics: alpha-Synuclein; Amyloid; Humans; Lewy Bodies; Neurodegenerative Diseases; Protein Aggregates; Protein Folding; Synucleinopathies

The review highlights various aspects of the influence of chaperones on amyloid proteins associated with the development of neurodegenerative diseases and includes studies conducted in our laboratory. Different sections of the article are devoted to the role of chaperones in the pathological transformation of alpha-synuclein and the prion protein. Information about the interaction of the chaperonins GroE and TRiC as well as polymer-based artificial chaperones with amyloidogenic proteins is summarized. Particular attention is paid to the effect of blocking chaperones by misfolded and amyloidogenic proteins. It was noted that the accumulation of functionally inactive chaperones blocked by misfolded proteins might cause the formation of amyloid aggregates and prevent the disassembly of fibrillar structures. Moreover, the blocking of chaperones by various forms of amyloid proteins might lead to pathological changes in the vital activity of cells due to the impaired folding of newly synthesized proteins and their subsequent processing. The final section of the article discusses both the little data on the role of gut microbiota in the propagation of synucleinopathies and prion diseases and the possible involvement of the bacterial chaperone GroE in these processes.

Topics: alpha-Synuclein; Amyloid; Amyloidogenic Proteins; Amyloidosis; Humans; Molecular Chaperones; Neurodegenerative Diseases; Prions

Many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, are characterised by the accumulation of misfolded protein deposits in the brain, leading to a progressive destabilisation of the neuronal network and neuronal death. Among the proteins that can abnormally accumulate are tau and α-synuclein, which can propagate in a prion-like manner and which upon aggregation, represent the most common intracellular proteinaceous lesions associated with neurodegeneration. For years it was thought that these intracellular proteins and their accumulation had no immediate relationship with extracellular homeostasis pathways such as the glymphatic clearance system; however, mounting evidence has now suggested that this is not the case. The involvement of the glymphatic system in neurodegenerative disease is yet to be fully defined; however, it is becoming increasingly clear that this pathway contributes to parenchymal solute clearance. Importantly, recent data show that proteins prone to intracellular accumulation are subject to glymphatic clearance, suggesting that this system plays a key role in many neurological disorders. In this review, we provide a background on the biology of tau and α-synuclein and discuss the latest findings on the cell-to-cell propagation mechanisms of these proteins. Importantly, we discuss recent data demonstrating that manipulation of the glymphatic system may have the potential to alleviate and reduce pathogenic accumulation of propagation-prone intracellular cytotoxic proteins. Furthermore, we will allude to the latest potential therapeutic opportunities targeting the glymphatic system that might have an impact as disease modifiers in neurodegenerative diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Brain; Glymphatic System; Humans; Neurodegenerative Diseases

Immune changes occur in all neurodegenerative conditions, but there are significant differences between diseases. For Parkinson's disease (PD), the immune system involvement is still being identified with considerable promise for therapeutic targeting. Post-mortem analyses of PD patient brains and pre-clinical cell and rodent models of PD identify increased inflammation in the brain and an elevation in central and peripheral pro-inflammatory cytokines. The cells involved include activated microglia surrounding degenerating neurons, currently thought to be neuroprotective in early disease stages but detrimental at later stages. Very different astrocytic reactions are found in the PD brain compared to other neurodegenerative conditions, with a loss of normal astrocyte functions contributing to a neurotoxic or dysfunctional phenotype (rather than classical astrogliosis found in all other neurodegenerative conditions). Astrocytes in PD are also actively involved in clearing α-synuclein away from vulnerable neurons, but the eventual accumulation of α-synuclein in their cytoplasm promotes a pro-inflammatory response and contributes to their dysfunctional phenotype and the spreading of PD pathology. Infiltration of peripheral immune cells also occurs in the PD brain, particularly T cells and monocytes. Both CD4 and CD8 T cells occur in regions of cell loss, with cytotoxic CD8 T cells occurring in the earliest stages and CD4 T helper cells occurring with disease progression. Current evidence points towards infiltrating monocytes as also playing a role in neuron death. Further characterisation of the successive molecular changes in both the resident and peripheral immune cells invading the PD brain will provide targets for disease modification.

Topics: alpha-Synuclein; Brain; Humans; Immunity; Microglia; Neurodegenerative Diseases; Parkinson Disease

Topics: alpha-Synuclein; Animals; Disease Progression; Humans; Mammals; Neurodegenerative Diseases; Parkinson Disease; Ubiquitin-Protein Ligases

Parkinson's disease (PD) is a chronic neurodegenerative disease mainly characterized by movement disorders and other non-motor symptoms, including the loss of dopaminergic neurons in the substantia nigra parts. Abnormal α-synuclein aggregation in the brain is closely associated with the loss of dopaminergic neurons. α-synuclein can propagate in the central nervous system (CNS) and periphery under pathological conditions. Many researches have focused on its aggregation and distribution in the CNS and explored its relationship with PD. But in recent years, the distribution of α-synuclein in peripheral tissues have been paid much attention. This review summarized the distribution of α-synuclein in the choroid plexus, blood, saliva, gastrointestine and other tissues, and discussed the potential mechanism of α-synuclein aggregation, providing a basis for the early diagnosis and intervention of PD.

Topics: alpha-Synuclein; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Parkinson Disease; Substantia Nigra

Parkinson's disease (PD) is a common neurodegenerative disease characterized by loss of dopaminergic neurons in the

Topics: alpha-Synuclein; Dopaminergic Neurons; Humans; Immunity; Neurodegenerative Diseases; Parkinson Disease; Substantia Nigra

Aggregation of specific proteins are histopathological hallmarks of several neurodegenerative diseases, such as, Amyloid β (Aβ) plaques and tau neurofibrillary tangles in Alzheimer's disease (AD); morphologically different inclusions of ratiometric 3 repeat (3 R) and 4 repeat (4 R) tau isoforms in progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and Pick's disease (PiD); α-Synuclein (α-Syn) containing Lewy bodies (LBs) and dystrophic Lewy neurites (LNs) in Parkinson's disease (PD) and dementia with Lewy bodies (DLB). However, mixed brain protein pathologies have been frequently observed in many of these diseases and in normal aging brains, among which Aβ/tau and tau/α-Syn crosstalks have received increased attention. Interestingly, studies have also shown synergistic interplay among Aβ, tau, and α-Syn in several neurodegenerative diseases, suggesting a protein triumvirate. In this review, we summarize the emerging evidence of Aβ, tau, and α-Syn aggregation in pathophysiology, and their overlap in a spectrum of neurodegenerative diseases including AD, PSP, PiD, CBD, PD and DLB. We discuss the prognostic advancements made in biomarker and imaging techniques in the triumvirate proteinopathies. Finally, we discuss the combined therapeutic modality involving biomarkers and imaging techniques for future combinatorial immunotherapeutic targeting more than one protein aggregates. We hope that such a multitarget therapeutic approach will have synergistic or additive effects to manage neurodegenerative diseases with two or more protein pathologies that might uncover a promising strategy for personalized combination therapies. Managing neurodegenerative diseases by optimizing the diagnostic criteria and the correct combination of immunotherapies will be a key factor in the success of future treatment.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease; Plaque, Amyloid; Protein Aggregation, Pathological; tau Proteins

Over the last decade, researchers have discovered that  a group of apparently unrelated neurodegenerative disorders, such as Parkinson's disease, have remarkable cellular and molecular biology similarities. Protein misfolding and aggregation are involved in all of the neurodegenerative conditions; as a result, inclusion bodies aggregation starts in the cells. Chaperone proteins and ubiquitin (26S proteasome's proteolysis signal), which aid in refolding misfolded proteins, are frequently found in these aggregates. The discovery of disease-causing gene alterations that code for multiple ubiquitin-proteasome pathway proteins in Parkinson's disease has strengthened the relationship between the ubiquitin-proteasome system and neurodegeneration. The specific molecular linkages between these systems and pathogenesis, on the other hand, are unknown and controversial. We outline the current level of knowledge in this article, focusing on important unanswered problems.

Topics: alpha-Synuclein; Humans; Molecular Chaperones; Neurodegenerative Diseases; Parkinson Disease; Proteasome Endopeptidase Complex; Ubiquitin

Intracellular accumulation of abnormal proteins with conformational changes is the defining neuropathological feature of neurodegenerative diseases. The pathogenic proteins that accumulate in patients' brains adopt an amyloid-like fibrous structure and exhibit various ultrastructural features. The biochemical analysis of pathogenic proteins in sarkosyl-insoluble fractions extracted from patients' brains also shows disease-specific features. Intriguingly, these ultrastructural and biochemical features are common within the same disease group. These differences among the pathogenic proteins extracted from patients' brains have important implications for definitive diagnosis of the disease, and also suggest the existence of pathogenic protein strains that contribute to the heterogeneity of pathogenesis in neurodegenerative diseases. Recent experimental evidence has shown that prion-like propagation of these pathogenic proteins from host cells to recipient cells underlies the onset and progression of neurodegenerative diseases. The reproduction of the pathological features that characterize each disease in cellular and animal models of prion-like propagation also implies that the structural differences in the pathogenic proteins are inherited in a prion-like manner. In this review, we summarize the ultrastructural and biochemical features of pathogenic proteins extracted from the brains of patients with neurodegenerative diseases that accumulate abnormal forms of tau, α-synuclein, and TDP-43, and we discuss how these disease-specific properties are maintained in the brain, based on recent experimental insights.

Topics: alpha-Synuclein; Animals; Brain; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Prions; tau Proteins

The two commonest groups of neurodegenerative disorders causing movement disorders are synucleinopathies and tauopathies. These disorders are characterised by the accumulation of abnormally misfolded forms of α-synuclein and tau proteins. Our current understanding of their pathogenesis suggests that extracellular forms of these proteins are of major relevance to the mechanism of pathology propagation throughout the brain and disease progression. The most novel approaches to find disease-modifying therapies aim to reduce or block these forms of tau and α-synuclein. This article reviews therapeutic strategies targeting α-synuclein and tau protein which have entered clinical development.

Topics: alpha-Synuclein; Humans; Movement Disorders; Neurodegenerative Diseases; tau Proteins; Tauopathies

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by the loss of dopaminergic neurons in the substantia nigra and the abnormal aggregation and accumulation of the alpha-synuclein (α-syn) protein into Lewy bodies. It is established that there is an association between inflammation and PD; however, the time course of the inflammatory process as well as the immune cells involved are still debated. Natural killer (NK) cells are innate lymphocytes with numerous functions including targeting and killing infected or malignant cells, antimicrobial defense, and resolving inflammation. NK cell subsets differ in their effector function capacities which are modulated by activating and inhibitory receptors expressed at the cell surface. Alterations in NK cell numbers and receptor expression have been reported in PD patients. Recently, NK cell numbers and frequency were shown to be altered in the periphery and in the central nervous system in a preclinical mouse model of PD. Moreover, NK cells have recently been shown to internalize and degrade α-syn aggregates and systemic NK cell depletion exacerbated synuclein pathology in a preclinical mouse model of PD, indicating a potential protective role of NK cells. Here, we review the inflammatory process in PD with a particular focus on alterations in NK cell numbers, phenotypes, and functions.

Topics: alpha-Synuclein; Animals; Inflammation; Killer Cells, Natural; Mice; Neurodegenerative Diseases; Parkinson Disease

α-synuclein (α-syn) is a highly conserved and thermostable protein that is widely distributed in human brain. An intracellular aggregation of α-syn in dopaminergic neurons is the hallmark of a group of neurodegenerative diseases including Parkinson's disease. Interestingly, α-syn is also highly expressed in red blood cells and is considered as one of the most abundant proteins in red blood cells. Moreover, α-syn is thought to play a regulatory role during normal erythropoiesis. However, whether α-syn participates in the pathogenesis of erythroid diseases has not been reported. In this review, we discuss the protein structure of α-syn and the importance of α-syn in erythropoiesis.

Topics: alpha-Synuclein; Brain; Erythropoiesis; Humans; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD), as a debilitating neurodegenerative disease, particularly affects the elderly population, and is clinically identified by resting tremor, rigidity, and bradykinesia. Pathophysiologically, PD is characterized by an early loss of dopaminergic neurons in the Substantia nigra pars compacta, accompanied by the extensive aggregation of alpha-synuclein (α-Syn) in the form of Lewy bodies. The onset of PD has been reported to be influenced by multiple biological molecules. In this context, circular RNAs (circRNAs), as tissue-specific noncoding RNAs with closed structures, have been recently demonstrated to involve in a set of PD's pathogenic processes. These RNA molecules can either up- or downregulate the expression of α-Syn, as well as moderating its accumulation through different regulatory mechanisms, in which targeting microRNAs (miRNAs) is considered the most common pathway. Since circRNAs have prominent structural and biological characteristics, they could also be considered as promising candidates for PD diagnosis and treatment. Unfortunately, PD has become a global health concern, and a large number of its pathogenic processes are still unclear; thus, it is crucial to elucidate the ambiguous aspects of PD pathophysiology to improve the efficiency of diagnostic and therapeutic strategies. In line with this fact, the current review aims to highlight the interplay between circRNAs and PD pathogenesis, and then discusses the diagnostic and therapeutic potential of circRNAs in PD progression. This study will thus be the first of its kind reviewing the relationship between circRNAs and PD.

Topics: Aged; alpha-Synuclein; Dopaminergic Neurons; Humans; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; RNA, Circular

Parkinson's disease (PD) is a neurodegenerative disease characterized pathologically by the formation of Lewy bodies comprised mainly of α-synuclein. Assessment of skin synuclein has the potential as an excellent diagnostic method with high sensitivity, specificity, and reproducibility that is also convenient and acceptable to patients. In this review, we summarize findings regarding the characteristics of cutaneous nerve p-α-syn or α-syn deposits and their correlations with clinical phenotypes in PD patients with and without orthostatic hypotension and LRRK2, GBA, and SNCA gene mutations. This review can serve as a reference for the diagnosis and classification of PD based on α-syn deposit patterns and to deeply explore its pathogenesis. FUNDING STATEMENT: The work was partly supported by the National Natural Science Key Foundation of China (No. 81830040 and No 82130042) and the Program of Excellent Talents in Medical Science of Jiangsu Province (No. JCRCA2016006) .

Topics: alpha-Synuclein; Gene Expression; Humans; Neurodegenerative Diseases; Parkinson Disease; Reproducibility of Results

Intracellular accumulations and aggregates of abnormal protein, consisting of amyloid-like fibrils, are common neuropathological features of many neurodegenerative diseases. The distributions and spreading of these pathological proteins are closely correlated with clinical symptoms and progression. Recent evidence supports the idea that template-mediated amplification of amyloid-like fibrils and intracellular propagation of fibril seeds are the main mechanisms by which pathological features spread along the neural circuits in the brain. Here, we review recent developments in the structural analysis of amyloid-like fibrils from brains of patients with various types of tauopathy and α-synucleinopathy, focusing on cryo-electron microscopy and mass analysis, and we discuss their relevance to the mechanisms of template-mediated amplification and intracellular propagation.

Topics: alpha-Synuclein; Amyloid; Brain; Cryoelectron Microscopy; Humans; Neurodegenerative Diseases; tau Proteins; Tauopathies

Parkinson's disease (PD) is a neurodegenerative disorder characterized by dopaminergic neurodegeneration and deposition of alpha-synuclein. Mechanisms associated with PD etiology include oxidative stress, apoptosis, autophagy, and abnormalities in neurotransmission, to name a few. Drugs used to treat PD have shown significant limitations in their efficacy. Therefore, recent focus has been placed on the potential of active plant ingredients as alternative, complementary, and efficient treatments. Berberine is an isoquinoline alkaloid that has shown promise as a pharmacological treatment in PD, given its ability to modulate several molecular pathway associated with the disease. Here, we review contemporary knowledge supporting the need to further characterize berberine as a potential treatment for PD.

Topics: alpha-Synuclein; Autophagy; Berberine; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder which affects 6.1 million people worldwide. The neuropathological hallmarks include the loss of dopaminergic neurons in the substantia nigra, the presence of Lewy bodies and Lewy neurites caused by α-synuclein aggregation, and neuroinflammation in the brain. The prodromal phase happens years before the onset of PD during which time many patients show gastro-intestinal symptoms. These symptoms are in support of Braak's theory and model where pathological α-synuclein propagates from the gut to the brain. Importantly, immune responses play a determinant role in the pathogenesis of Parkinson's disease. The innate immune responses triggered by microglia can cause neuronal death and disease progression. In addition, T cells infiltrate into the brains of PD patients and become involved in the adaptive immune responses. Interestingly, α-synuclein is associated with both innate and adaptive immune responses by directly interacting with microglia and T cells. Here, we give a detailed review of the immunobiology of Parkinson's disease, focusing on the role α-synuclein in the gut-brain axis hypothesis, the innate and adaptive immune responses involved in the disease, and current treatments.

Topics: alpha-Synuclein; Brain; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Parkinson Disease

Neuronal death underlies the symptoms of several human neurological disorders, including Alzheimer's, Parkinson's and Huntington's diseases, and amyotrophic lateral sclerosis and their precise pathophysiology have not yet been elucidated. According to various studies, the prohibition is the best therapy with neuroprotective approaches, which are advanced and safe methods.. This review summarizes some of the already-known and newly emerged neuroprotective targets and strategies and their experimental effects have also been reported. Accordingly, literature was studied from 2000 to 2021, and appropriate articles were searched in Google Scholar and Scopus with the keywords given in the keywords section of the current review.. Lewy bodies are the histopathologic characteristics of neurodegenerative disorders and are protein-rich intracellular deposits in which Alpha-synuclein is its major protein. Alphasynuclein's toxic potential provides a compelling rationale for therapeutic strategies aimed at decreasing its burden in neuronal cells through numerous pathways, including ubiquitin-proteasome system and autophagy-lysosome pathway, proteolytic breakdown via cathepsin D, kallikrein-6 (neurosin), calpain-1 or MMP9, heat shock proteins, and proteolysis targeting chimera which consists of a target protein-ligand and an E3 ubiquitin ligase (E3) followed by target protein ubiquitination (PROTACs). Other targets that have been noticed recently are the mutant huntingtin, tau proteins and glycogen synthase kinase 3β; their accumulation proceeds extensive neuronal damage and up to the minute approach such as proteolysis targeting chimera promotes its degradation in cells. Various studies demonstrated that Mendelian gene mutations can result in neurodegenerative diseases. An additional target that has gained much interest is epigenetics, such as mutation, phosphodiesterase, RNA binding proteins and Nuclear respiratory factor 1.. The novel molecular targets and new strategies compiled and introduced here can be used by scientists to design and discover more efficient small molecule drugs against neurodegenerative diseases. And also, the genes in which their mutations can lead to the α-synuclein aggregation or accumulation have been discussed and considered a valuable information on epigenetics in dementia.

Topics: alpha-Synuclein; Autophagy; Humans; Neurodegenerative Diseases; Neurons

Microglia are the primary resident immune cells of the central nervous system. Neuropathological reports have identified augmented microglial activation in brains of patients with neurodegenerative disorders including Parkinson's disease (PD). Extensive research over the years has strengthened the current view on microglia as a player in the pathogenesis of PD and other α-synucleinopathies. In this review, we summarize key findings of the recent three years on microglia in PD with specific relevance to understanding its heterogeneity, dual nature, and specific interactions with pathological α-synuclein strains to mediate its clearance and spreading. This review provides evidence on the relevance of microglia as a putative biomarker and therapeutic target in PD and related disorders.

Topics: alpha-Synuclein; Brain; Humans; Microglia; Neurodegenerative Diseases; Parkinson Disease

Lysosomes have a critical role in maintaining normal cellular homeostasis mediated by their involvement in secretion, plasma membrane repair, cell signaling and energy metabolism. Lysosomal storage disorders (LSDs) are a group of approximately 50 rare disorders caused by lysosomal dysfunction that occur due to mutations in a gene of a lysosomal protein. Gaucher disease (GD), an autosomal recessive disorder and one of the most common LSDs, is caused by the deficiency of the lysosomal enzyme acid-β-glucocerebrosidase (GCase), due to biallelic mutations in the GBA1 gene. Reduced GCase activity leads to the accumulation of glucosylceramide (GlcCer), which is deacylated by lysosomal acid ceramidase to a toxic metabolite, glucosylshpingosine (GlcSph). Most GBA1 variants are recognized as misfolded in the ER, where the retention for refolding attempts initiates stress and activates the stress response known as the Unfolded Protein Response (UPR). The distinct clinical subtypes of GD are based on whether there is primary involvement of the central nervous system. Type 1 GD (GD1) is the nonneuropathic type, however, the recent recognition of the association of GD with the development of parkinsonism defies this classification. Patients with GD1 and carriers of GBA1 mutations are at risk for the development of parkinsonian manifestations. Parkinson disease (PD), the second most prevalent neurodegenerative disease, culminates in a movement disorder with the premature death of the patients. In PD and related disorders, collectively called synucleinopathies, the hallmark pathology is α-synuclein positive aggregates referred to as Lewy bodies or Lewy neurites and the death of dopaminergic neurons. While PD is mostly sporadic, in ∼5-10% of cases, the disease results from pathogenic variants in a growing number of genes. The most common genetic cause of PD is mutations in GBA1. Two mechanisms have been proposed for this link: (A) a "gain of function" mechanism, in which mutant GCase (protein) contributes to aggregate formation and to the development of PD, and the (B) "haploinsufficiency" ("loss of function") model, suggesting that one normal GBA1 allele is insufficient to carry adequate GCase activity and functional deficiency of GCase impedes α-synuclein metabolism. Lysosomal dysfunction, compromised autophagy and mitophagy further enhance the accumulation of α-synuclein, which results in the development of PD pathology. The present review will elaborate on the biology

Topics: alpha-Synuclein; Gaucher Disease; Glucosylceramidase; Humans; Lysosomes; Mutation; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is the second-most-common neurodegenerative disease characterized by motor and non-motor dysfunctions, which currently affects about 10 million people worldwide. Gradual death and progressive loss of dopaminergic neurons in the pars compacta region of substantia nigra result in striatal dopamine deficiency in PD. Specific mutation with further aggregation of α-synuclein in the intraneuronal inclusion bodies is considered the neuropathological hallmark of this disease. PD is often associated with various organelle dysfunctions inside a dopaminergic neuron, including mitochondrial damage, proteasomal impairment, and production of reactive oxygen species, thus causing subsequent neuronal death. Apart from several genetic and non-genetic risk factors, emerging research establishes an association between cardiovascular diseases, including coronary heart disease, myocardial infarction, congestive heart failure, and ischemic stroke with PD. The majority of these cardiovascular diseases have an origin from atherosclerosis, where endothelial dysfunction following thrombus formation is significantly regulated by blood platelet. This non-nucleated cell fragment expresses not only neuron-specific molecules and receptors but also several PD-specific biomarkers such as α-synuclein, parkin, PTEN-induced kinase-1, tyrosine hydroxylase, dopamine transporter, thus making platelet a suitable peripheral model for PD. Besides its similarity with a dopaminergic neuron, platelet structural alterations, as well as functional abnormalities, are also evident in PD. However, the molecular mechanism behind platelet dysfunction is still elusive and quite controversial. This state-of-the-art review describes the detailed mechanism of platelet impairment in PD, addressing the novel platelet-associated therapeutic drug candidates for plausible PD management.

Topics: alpha-Synuclein; Blood Platelets; Cardiovascular Diseases; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Parkinson Disease; Precision Medicine; Substantia Nigra

Parkinson's disease (PD) pathology is the most common motor neurodegenerative disease that occurs due to the progressive degeneration of dopaminergic neurons of the nigrostriatal pathway of the brain. The histopathological hallmark of the disease is fibrillary aggregate called Lewy bodies which majorly contain α-synuclein, suggesting the critical implication of diminished protein degradation mechanisms in disease pathogenesis. This α-synuclein-containing Lewy bodies are evident in both experimental models as well as in postmortem PD brain and are speculated to be pathogenic but still, the lineal association between these aggregates and the complexity of disease pathology is not yet well established and needs further attention. However, it has been reported that α-synuclein aggregates have consorted with the declined proteasome and lysosome activities. Therefore, in this review, we reappraise intracellular protein degradation mechanisms during PD pathology. This article focused on the findings of the last two decades suggesting the implications of protein degradation mechanisms in disease pathogenesis and based on shreds of evidence, some of the approaches are also suggested which may be adopted to find out the novel therapeutic targets for the management of PD patients.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease; Proteasome Endopeptidase Complex; Proteolysis

Inflammasomes are multiprotein complexes that are mainly present in resident and infiltrating immune cells in the central nervous system. Inflammasomes function as intracellular sensors of immunometabolic stress, infection and changes in the local microenvironment. Inflammasome assembly in response to these 'danger signals', triggers recruitment and cluster-dependent activation of caspase-1 and the subsequent proteolytic activation of inflammatory cytokines such as interleukin-1β and interleukin-18. This is typically followed by a form of inflammatory cell death through pyroptosis. Since the discovery of inflammasomes in 2002, they have come to be recognized as central regulators of acute and chronic inflammation, a hallmark of progressive neurological diseases. Indeed, over the last decade, extensive inflammasome activation has been found at the sites of neuropathology in all progressive neurodegenerative diseases. Disease-specific misfolded protein aggregates which accumulate in neurodegenerative diseases, such as alpha synuclein or beta amyloid, have been found to be important triggers of NLRP3 inflammasome activation in the central nervous system. Together, these discoveries have transformed our understanding of how chronic inflammation is triggered and sustained in the central nervous system, and how it can contribute to neuronal death and disease progression in age-related neurodegenerative diseases. Therapeutic strategies around inhibition of NLRP3 activation in the central nervous system are already being evaluated to determine their effectiveness to slow progressive neurodegeneration. This review summarizes current understanding of inflammasomes in the most prevalent neurodegenerative diseases and discusses current knowledge gaps and inflammasome inhibition as a therapeutic strategy.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Caspase 1; Humans; Inflammasomes; Inflammation; Interleukin-18; Interleukin-1beta; Neurodegenerative Diseases; NLR Family, Pyrin Domain-Containing 3 Protein; Protein Aggregates

Parkinson's disease (PD) is the second most common neurodegenerative disease, with two main pathological features: misfolded α-synuclein protein accumulation and neurodegeneration. Inflammation has recently been identified as a contributor to a cascade of events that may aggravate PD pathology. Inflammasomes, a group of intracellular protein complexes, play an important role in innate immune responses to various diseases, including infection. In PD research, accumulating evidence suggests that α-synuclein aggregations may activate inflammasomes, particularly the nucleotide-binding oligomerization domain-leucine-rich repeat-pyrin domain-containing 3 (NLRP3) type, which exacerbates inflammation in the central nervous system by secreting proinflammatory cytokines like interleukin (IL)-18 and IL-1β. Afterward, activated NLRP3 triggers local microglia and astrocytes to release additional IL-1β. In turn, the activated inflammatory process may contribute to additional α-synuclein aggregation and cell loss. This review summarizes current research evidence on how the NLRP3 inflammasome contributes to PD pathogenesis, as well as potential therapeutic strategies targeting the NLRP3 inflammasome in PD.

Topics: alpha-Synuclein; Cytokines; Humans; Inflammasomes; Inflammation; Leucine; Neurodegenerative Diseases; NLR Family, Pyrin Domain-Containing 3 Protein; Nucleotides; Parkinson Disease

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

Dementia with Lewy bodies (DLB) is a neurodegenerative disease linked to abnormal accumulation of phosphorylated α-synuclein. GBA1 is the gene encoding the lysosomal enzyme glucocerebrosidase (GCase), whose mutations are a risk factor of DLB.. To report all available data exploring the association between GBA1 mutations and DLB.. All publications focused on GCase and DLB in humans between 2003 and 2022 were identified on PubMed, Cochrane and ClinicalTrials.gov.. 29 studies were included and confirmed the strong association between GBA1 mutations and DLB (Odds Ratio [OR]: 8.28). GBA1 mutation carriers presented a more malignant phenotype, with earlier symptom onset, more severe motor and cognitive dysfunctions, more visual hallucinations and rapid eye movement sleep disorder. GBA1 mutations were associated with "purer" neuropathological DLB. No therapeutic recommendations exist and clinical trials targeting GCase are just starting in DLB patients.. This review reports a link between GBA1 mutations and the DLB phenotype with limited evidence due to the small number of studies.

Topics: alpha-Synuclein; Glucosylceramidase; Humans; Lewy Body Disease; Mutation; Neurodegenerative Diseases

Parkinson's disease (PD) is a common neurodegenerative condition affecting a significant number of individuals globally, resulting in the presentation of debilitating motor and non-motor symptoms, including bradykinesia, resting tremor, as well as mood and sleep disorders. The pathology of PD has been observed to spread through the central nervous system resulting in progressive brain degeneration and a poor prognosis. Aggregated forms of the protein α-synuclein, particularly intermediary aggregates, referred to as oligomers, or preformed fibrils, have been implicated as the causative agent in the degeneration of neuronal processes, including the dysfunction of axonal transport, mitochondrial activity, and ultimately cellular death. Extracellular vesicles (EVs) have been strongly implicated in the propagation of PD pathology. Current observations suggest that aggregated α-synuclein is transported between neurons via small EVs in a series of exocytosis and endocytosis cellular processes leading to the observed spread of neurotoxicity and cellular death. Despite some understanding of the role of EVs in neurodegeneration, the exact mechanism by which these lipidic particles participate in the progression of Parkinson's pathology is not entirely understood. Here we review the current understanding of the role of EVs in the propagation of PD and explore their potential as a therapeutic target.

Topics: alpha-Synuclein; Extracellular Vesicles; Humans; Neurodegenerative Diseases; Neurons; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting millions each year. Most PD cases (∼90%) are sporadic, resulting from the age-dependent accumulation of pathogenic effects. One key pathological hallmark of PD progression is the accumulation of alpha-synuclein (α-syn), which has been shown to negatively affect neuronal function and viability. Here, using 3- and 6-month-old Nrf2

Topics: alpha-Synuclein; Animals; Ferroptosis; Humans; Infant; Mice; Neurodegenerative Diseases; NF-E2-Related Factor 2; Parkinson Disease

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

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

Synucleinopathies are a group of neurodegenerative disorders caused by the accumulation of toxic species of α-synuclein. The common clinical features are chronic progressive decline of motor, cognitive, behavioral, and autonomic functions. They include Parkinson's disease, dementia with Lewy body, and multiple system atrophy. Their etiology has not been clarified and multiple pathogenic factors include oxidative stress, mitochondrial dysfunction, impaired protein degradation systems, and neuroinflammation. Current available therapy cannot prevent progressive neurodegeneration and "disease-modifying or neuroprotective" therapy has been proposed. This paper presents the molecular mechanisms of neuroprotection by the inhibitors of type B monoamine oxidase, rasagiline and selegiline. They prevent mitochondrial apoptosis, induce anti-apoptotic Bcl-2 protein family, and pro-survival brain- and glial cell line-derived neurotrophic factors. They also prevent toxic oligomerization and aggregation of α-synuclein. Monoamine oxidase is involved in neurodegeneration and neuroprotection, independently of the catalytic activity. Type A monoamine oxidases mediates rasagiline-activated signaling pathways to induce neuroprotective genes in neuronal cells. Multi-targeting propargylamine derivatives have been developed for therapy in various neurodegenerative diseases. Preclinical studies have presented neuroprotection of rasagiline and selegiline, but beneficial effects have been scarcely presented. Strategy to improve clinical trials is discussed to achieve disease-modification in synucleinopathies.

Topics: alpha-Synuclein; Glial Cell Line-Derived Neurotrophic Factors; Humans; Indans; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Neurodegenerative Diseases; Neuroprotection; Neuroprotective Agents; Proto-Oncogene Proteins c-bcl-2; Selegiline; Synucleinopathies

Neurodegenerative diseases (NDDs) are the main cause of dementia in the elderly, having no cure to date, as the currently available therapies focus on symptom remission. Most NDDs will progress despite treatment and eventually result in the death of the patient after several years of a burden on both the patient and the caregivers. Therefore, it is necessary to investigate agents that tackle the disease pathogenesis and can efficiently slow down or halt disease progression, with the hope of curing the patients and preventing further burden and mortality. Accordingly, recent research has focused on disease-modifying treatments with neuroregenerative or neuroprotective effects. For this purpose, it is necessary to understand the pathogenesis of NDDs. It has been shown that oxidative stress plays an important role in the damage to the central nervous system and the progression of neurodegenerative disorders. Furthermore, mitochondrial dysfunction and the accumulation of unfolded proteins, including beta-amyloid (Aβ), tau proteins, and α-synuclein, have been suggested. Accordingly, cellular and molecular studies have investigated the efficacy of several natural compounds (herbs and nutritional agents) for their neuroprotective and antioxidative properties. The most popular herbs suggested for the treatment and/or prevention of NDDs include Withania somnifera (ashwagandha), ginseng, curcumin, resveratrol, Baccopa monnieri, and Ginkgo biloba. In some herbs, such as ginseng, preclinical and clinical evidence are available for supporting its effectiveness; however, in some others, only cellular and animal studies are available. In line with the scant literature in terms of the effectiveness of herbal compounds on NDDs, there are also other herbal agents that have been disregarded. Picein is one of the herbal agents that has been investigated in only a few studies. Picein is the active ingredient of several herbs and can be thus extracted from different types of herbs, which makes it more available. It has shown to have anti-inflammatory properties in cellular and plant studies; however, to date, only one study has suggested its neuroprotective properties. Furthermore, some cellular studies have shown no anti-inflammatory effect of picein. Therefore, a review of the available literature is required to summarize the results of studies on picein. To date, no review study seems to have addressed this issue. Thus, in the present study, we gather the available informat

Topics: alpha-Synuclein; Animals; Antioxidants; Curcumin; Glucosides; Neurodegenerative Diseases; Neuroprotective Agents; Panax; Resveratrol; tau Proteins; Withania

Parkinson's disease (PD) is a neurodegenerative disease second only to Alzheimer's disease in terms of prevalence. Previous studies have indicated that the occurrence and progression of PD are associated with mitochondrial dysfunction. Mitochondrial dysfunction is one of the most important causes for apoptosis of dopaminergic neurons. Therefore, maintaining the stability of mitochondrial functioning is a potential strategy in the treatment of PD. Voltage-dependent anion channel (VDAC) is the main component in the outer mitochondrial membrane, and it participates in a variety of biological processes. In this review, we focus on the potential roles of VDACs in the treatment of PD. We found that VDACs are involved in PD by regulating apoptosis, autophagy, and ferroptosis. VDAC1 oligomerization, VDACs ubiquitination, regulation of mitochondrial permeability transition pore (mPTP) by VDACs, and interaction between VDACs and

Topics: alpha-Synuclein; Humans; Mitochondrial Permeability Transition Pore; Neurodegenerative Diseases; Parkinson Disease; Voltage-Dependent Anion Channels

The pathological features of PDD are represented by dopaminergic neuronal death and intracellular

Topics: alpha-Synuclein; Alzheimer Disease; Dementia; Ferroptosis; Humans; Iron; Iron Regulatory Protein 1; Iron Regulatory Protein 2; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological; tau Proteins

Improving the quality of life in developed countries has contributed to an increase in its duration, which has led to an increase in the number of reported cases of Alzheimer's disease (AD) and Parkinson's disease (PD) in the world. Today, there are 26.6 million patients with AD in the world and it is suspected that by 2050 the number of such patients may increase four times. Additionally, PD in different countries is recorded among people above 60-65 years old at a level of 167 to 5703 per 100.000 population. The latest studies have made it possible to formulate the main mechanisms of the «microbiota-gut-brain» axis associated with the pathogenesis of some neurodegenerative diseases. In this review, we summarize the currently available information on the possible role of the gut microbiota in the AD and PD development. It was shown that oxidative stress is one of the main pathogenetic mechanisms of the development of neurodegenerative diseases. In addition, the deposition of lipopolysaccharides of gram-negative bacteria and amyloid of microbial origin in the brain tissue of patients with impaired permeability of the intestinal barrier plays an important role in AD. In PD, the synthesis of α-synuclein produced by bacteria and neuroinflammation are of the greatest importance. Knowledge of these mechanisms will allow the development of psychobiotics, which will reduce the risk of neurodegeneration in AD and PD.. Повышение качества жизни в развитых странах способствовало увеличению ее продолжительности, что привело к повышению количества зарегистрированных в мире случаев болезни Альцгеймера (БА) и болезни Паркинсона (БП). Сегодня в мире насчитывается 26,6 млн больных БА, и предполагают, что к 2050 г. число таких пациентов может увеличиться в 4 раза. В свою очередь БП в разных странах регистрируется среди людей старше 60—65 лет на уровне от 167 до 5703 на 100 тыс. населения. Исследования, проведенные в последние годы, позволили сформулировать основные механизмы работы оси «микробиота—кишечник—мозг», которые, как оказалось, могут определять риск развития некоторых нейродегенеративных заболеваний. В настоящем обзоре мы решили обобщить имеющуюся к настоящему моменту информацию о роли микробиоты в патологии нервной системы, сконцентрировав наше внимание на влиянии микробиоты кишечника на риск развития БА и БП. В ходе анализа публикаций показано, что окислительный стресс является одним из ключевых патогенетических механизмов развития нейродегенеративных заболеваний. Кроме того, при БА важную роль играет накопление в мозговой ткани пациентов липополисахаридов грамнегативных бактерий и амилоида микробного происхождения при нарушении проницаемости кишечного барьера. При возникновении же БП наибольшее значение имеют синтез бактериями микробиоты α-синуклеина и нейровоспаление. Знание этих механизмов позволит разработать препараты пробиотиков (так называемых психобиотиков), которые помогут снизить риск нейродегенерации при БА и БП.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Humans; Lipopolysaccharides; Microbiota; Middle Aged; Neurodegenerative Diseases; Parkinson Disease; Quality of Life

Parkinson's disease (PD) is a multisystem alpha-synucleinopathic neurodegenerative disease and the most prevalent neurodegenerative disorder after Alzheimer's disease with a high incidence rate in the elderly population. PD is highly multifactorial in etiology and has complex and wide-ranging pathogenic mechanisms. Environmental exposures and genetic predisposition are prominent risk factors. However, current evidence suggests that an intimate link may exist between the risk factor of sleep disturbance and PD pathogenesis. PD is characterized by the pathological hallmarks of alpha-synuclein aggregations and dopaminergic neuron degeneration in the substantia nigra. The loss of dopamine-producing neurons results in both motor and non-motor symptoms, most commonly, bradykinesia, tremor, rigidity, psychiatric disorders, sleep disorders and gastrointestinal problems. Factors that may exacerbate alpha-synuclein accumulation and dopamine neuron loss include neuroinflammation and glymphatic system impairment. Extracellular alpha-synuclein can induce an inflammatory response which can lead to neural cell death and inhibition of neurogenesis. The glymphatic system functions most optimally to remove extracellular brain solutes during sleep and therefore sleep disruption may be a crucial progression factor as well as a risk factor. This literature review interprets and analyses data from experimental and epidemiological studies to determine the recent advances in establishing a relationship between glymphatic system dysfunction, sleep disturbance, and PD pathogenesis and progression. This review addresses current limitations surrounding the ability to affirm a causal link between improved glymphatic clearance by increased sleep quality in PD prevention and management. Furthermore, this review proposes potential therapeutic approaches that could utilize the protective mechanism of sleep, to promote glymphatic clearance that therefore may reduce disease progression as well as symptom severity in PD patients.

Topics: Aged; alpha-Synuclein; Dopamine; Glymphatic System; Humans; Nerve Degeneration; Neurodegenerative Diseases; Parkinson Disease; Sleep; Sleep Wake Disorders

Molecular chaperones and co-chaperones facilitate the assembly of newly synthesized polypeptides and refolding of unfolded or misfolded proteins, thereby maintaining protein homeostasis in cells. As co-chaperones of the master chaperone heat shock protein (HSP) 70, the HSP40 (DNAJ) proteins are largest chaperone family in eukaryotic cells. They contain a characteristic J-domain which mediates interaction with HSP70, thereby helping protein folding. It is well perceived that protein homeostasis is vital for neuronal health. DNAJ family proteins have been linked to the occurrence and progression of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, spinocerebellar ataxia, Charcot-Marie-Tooth disease, spinal muscular atrophy, distal hereditary motor neuropathy, limb-girdle type muscular dystrophy, neuronal ceroid lipofuscinosis and essential tremor in recent studies. DNAJA1 effectively degrades huntington aggregates; DNAJB1 can degrade protein aggregates ataxin-3; DNAJB2 can inhibit the formation of huntington aggregates; DNAJB6 can inhibit the aggregation of Aβ

Topics: alpha-Synuclein; Essential Tremor; HSP40 Heat-Shock Proteins; Humans; Molecular Chaperones; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Folding

Diabetic retinopathy, the most common complication of diabetes, is a neurodegenerative disease in the eye. And Parkinson's disease, affecting the health of 1-2% of people over 60 years old throughout the world, is the second largest neurodegenerative disease in the brain. As the understanding of diabetic retinopathy and Parkinson's disease deepens, the two diseases are found to show correlation in incidence, similarity in clinical presentation, and close association in pathophysiological mechanisms. To reveal the association between pathophysiological mechanisms of the two disease, in this review, the shared pathophysiological factors of diabetic retinopathy and Parkinson's disease are summarized and classified into dopaminergic system, circadian rhythm, neurotrophic factors, α-synuclein, and Wnt signaling pathways. Furthermore, similar and different mechanisms so far as the shared pathophysiological factors of the two disorders are discussed systematically. Finally, a brief summary and new perspectives are presented to provide new directions for further efforts on the association, exploration, and clinical prevention and treatment of diabetic retinopathy and Parkinson's disease.

Topics: alpha-Synuclein; Brain; Diabetes Mellitus; Diabetic Retinopathy; Dopamine; Humans; Middle Aged; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) and related neurodegenerative disorders, termed the synucleinopathies, are characterized pathologically by the accumulation of protein aggregates containing α-synuclein (aSyn), resulting in progressive neuronal loss. There is considerable need for the development of neuroprotective strategies to halt or slow disease progression in these disorders. To this end, evaluation of genetic mutations associated with the synucleinopathies has helped to elucidate crucial mechanisms of disease pathogenesis, revealing key roles for lysosomal and mitochondrial dysfunction. The GBA1 gene, which encodes the lysosomal hydrolase β-glucocerebrosidase (GCase) is the most common genetic risk factor for PD and is also linked to other neurodegenerative disorders including dementia with Lewy bodies (DLB). Additionally, homozygous mutations in GBA1 are associated with the rare lysosomal storage disorder, Gaucher's disease (GD). In this review, we discuss the current knowledge in the field regarding the diverse roles of GCase in neurons and the multifactorial effects of loss of GCase enzymatic activity. Importantly, GCase has been shown to have a bidirectional relationship with aSyn, resulting in a pathogenic feedback loop that can lead to progressive aSyn accumulation. Alterations in GCase activity have furthermore been linked to multiple distinct pathways involved in neurodegeneration, and therefore GCase has emerged as a promising target for therapeutic drug development for PD and related neurodegenerative disorders, particularly DLB.

Topics: alpha-Synuclein; Gaucher Disease; Glucosylceramidase; Humans; Lysosomes; Neurodegenerative Diseases; Parkinson Disease

The study of platelets in the context of neurodegenerative diseases is intensifying, and increasing evidence suggests that platelets may play an important role in the pathogenesis of neurodegenerative disorders. Therefore, we aim to provide a comprehensive overview of the role of platelets and their diverse activation pathways in the development of these diseases.. Platelets participate in synaptic plasticity, learning, memory, and platelets activated by exercise promote neuronal differentiation in several brain regions. Platelets also contribute to the immune response by modulating their surface protein profile and releasing pro- and anti-inflammatory mediators. In Alzheimer's disease, increased levels of platelet amyloid precursor protein raise the production of amyloid-beta peptides promoting platelet activation, triggering at the same time amyloid-beta fibrillation. In Parkinson's disease, increased platelet α-synuclein is associated with elevated ROS production and mitochondrial dysfunction.. In this review, we revise different platelet activation pathways, those classically involved in hemostasis and wound healing, and alternative activation pathways recently described in the context of neurodegenerative diseases, especially in Alzheimer's disease.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Blood Platelets; Cell Differentiation; Humans; Mitochondria; Neurodegenerative Diseases; Neuronal Plasticity; Parkinson Disease; Platelet Activation; Reactive Oxygen Species

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) is a common neurodegenerative disorder that primarily affects the elderly. While the etiology of PD is likely multifactorial with the involvement of genetic, environmental, aging and other factors, α-synuclein (α-syn) pathology is a pivotal mechanism underlying the development of PD. In recent years, astrocytes have attracted considerable attention in the field. Although astrocytes perform a variety of physiological functions in the brain, they are pivotal mediators of α-syn toxicity since they internalize α-syn released from damaged neurons, and this triggers an inflammatory response, protein degradation dysfunction, mitochondrial dysfunction and endoplasmic reticulum stress. Astrocytes are indispensable coordinators in the background of several genetic mutations, including PARK7, GBA1, LRRK2, ATP13A2, PINK1, PRKN and PLA2G6. As the most abundant glial cells in the brain, functional astrocytes can be replenished and even converted to functional neurons. In this review, we discuss astrocyte dysfunction in PD with an emphasis on α-syn toxicity and genetic modulation and conclude that astrocyte replenishment is a valuable therapeutic approach in PD.

Topics: Aged; alpha-Synuclein; Astrocytes; Humans; Neurodegenerative Diseases; Parkinson Disease; Synucleinopathies

The key aspect of the classification of neurodegenerative diseases is the histopathological detection of certain proteins in the brain. The various disease entities are distinguished with respect to the type of detected protein and with respect to the configuration and localization of the corresponding protein aggregates. Aggregates of alpha-synuclein (ASYN) are the defining hallmark of several neurodegenerative disorders termed synucleinopathies. The most well-known diseases in this spectrum are Parkinson's disease (PD) with neuronal detection of Lewy bodies, dementia with Lewy bodies (DLB), with additional detection of beta-amyloid and multiple system atrophy (MSA), where ASYN aggregates are found in glia cells in the form of Papp-Lantos inclusions. ASYN has been identified as a key target for the development of therapeutic approaches to synucleinopathies given its central role in the pathophysiology of these diseases. Current treatment strategies can be roughly classified into six groups: 1) lowering ASYN expression (antisense therapy), 2) inhibition of formation of toxic ASYN aggregates (aggregation inhibitors, chelators), 3) dissolving or removal of intracellular or extracellular toxic AYSN aggregates (active and passive immunotherapy, aggregation inhibitors), 4) enhancement of cellular clearance mechanisms (autophagy, lysosomal microphagy) for removal of toxic forms of alpha-synuclein, 5) modulation of neuroinflammatory processes and 6) neuroprotective strategies. This article summarizes the current therapeutic approaches and sheds light on promising future treatment approaches.. Kernpunkt der Klassifikation neurodegenerativer Erkrankungen ist der histopathologische Nachweis von Ablagerungen bestimmter Proteine im Gehirn. Hierbei unterscheiden sich die verschiedenen Krankheitsentitäten sowohl hinsichtlich der Art der nachweisbaren Proteine als auch hinsichtlich der Konfiguration und Lokalisation der entsprechenden Proteinaggregate. Gemeinsames Kernmerkmal der als Synukleinopathien zusammengefassten Erkrankungen sind Ablagerungen des Proteins α‑Synuklein (ASYN). Die bekanntesten Erkrankungen dieses Spektrums sind die Parkinson-Krankheit (PK) mit neuronalem Nachweis von Lewy-Körperchen, die Demenz vom Lewy-Körper-Typ (DLK) mit zusätzlichem Nachweis von β‑Amyloid-Ablagerungen sowie die seltene Multisystematrophie (MSA) mit glialem Nachweis sog. Papp-Lantos-Körperchen. Da neben der diagnostischen mittlerweile auch die zentrale pathophysiologische Bedeutung des ASYN erwiesen ist, fokussiert sich die Entwicklung neuer Therapien aktuell auf die Beeinflussung der toxischen Wirkung dieses Proteins. Die verschiedenen Therapiekonzepte lassen sich grob in sechs Gruppen zusammenfassen: 1. die Verringerung der ASYN-Expression (Antisense-Therapie), 2. die Verhinderung der Bildung toxischer ASYN-Aggregate (Antiaggregativa, Chelatoren), 3. das Auflösen bzw. die Beseitigung intra- oder extrazellulärer toxischer ASYN-Aggregate (aktive und passive Immuntherapie, Antiaggregativa), 4. die Verstärkung zellulärer Abräummechanismen (Autophagie, lysosomale Mikrophagie) zur Beseitigung toxischer Formen von α‑Synuklein, 5. die Modulation neuroinflammatorischer Prozesse sowie 6. neuroprotektive Strategien. In diesem Artikel fassen wir die aktuellen Therapieentwicklungen zusammen und geben einen Ausblick auf vielversprechende zukünftige Therapieansätze.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Neurons; Parkinson Disease; Synucleinopathies

Parkinson' disease (PD) is a common neurodegenerative disease with the pathological hallmark of alpha-synuclein aggregation within dopaminergic neurons. The etiology of PD comes from a complex interplay between genetic and environmental factors. Though most cases of PD are sporadic; a family history of PD is found in approximately 15% of patients. Pathogenic mutations are found in 5% to 10% of individuals with either familial or sporadic PD. In recent decades, because of the advent of next generation sequencing, more than 25 genes have been identified as causative genes in PD. These findings allow better understanding of the pathogenesis of PD, including aberrant alpha-synuclein homeostasis, defective mitochondrial functions, and impairment of the ubiquitin-proteasome and autophagy-lysosome pathways. Among the PD-causative genes, LRRK2 mutation is the most frequent mutation in autosomal dominant PD and Parkin mutation is prevalent in patients with autosomal recessive or early onset PD. Several genetic epidemiology studies in Asians have revealed a distinctive mutation spectrum from Western populations, reinforcing the importance of ethnic differences in PD. Proper genetic testing is recommended for patients with early onset, a strong family history, or associated red flag clinical features. Considering that clinical trials of disease-modifying therapy targeting patients with specific mutations are ongoing and we are in the era of precision medicine, this review highlights recent updates of genetic findings in patients with PD, focusing on Asian populations and practical recommendations for genetic testing. Keywords: Parkinson's disease, Genetics.

Topics: alpha-Synuclein; Humans; Mutation; Neurodegenerative Diseases; Parkinson Disease

The aggregation of proteins into amyloid fibers is linked to more than forty still incurable cellular and neurodegenerative diseases such as Parkinson's disease (PD), multiple system atrophy, Alzheimer's disease and type 2 diabetes, among others. The process of amyloid formation is a main feature of cell degeneration and disease pathogenesis. Despite being methodologically challenging, a complete understanding of the molecular mechanism of aggregation, especially in the early stages, is essential to find new biological targets for innovative therapies. Here, we reviewed selected examples on α-syn showing how complementary approaches, which employ different biophysical techniques and models, can better deal with a comprehensive study of amyloid aggregation. In addition to the monomer aggregation and conformational transition hypothesis, we reported new emerging theories regarding the self-aggregation of α-syn, such as the alpha-helix rich tetramer hypothesis, whose destabilization induce monomer aggregation; and the liquid-liquid phase separation hypothesis, which considers a phase separation of α-syn into liquid droplets as a primary event towards the evolution to aggregates. The final aim of this review is to show how multimodal methodologies provide a complete portrait of α-syn oligomerization and can be successfully extended to other protein aggregation diseases.

Topics: alpha-Synuclein; Amyloidogenic Proteins; Amyloidosis; Animals; Disease Susceptibility; Humans; Hydrophobic and Hydrophilic Interactions; Liquid-Liquid Extraction; Models, Molecular; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; Protein Conformation; Protein Multimerization; Structure-Activity Relationship

The critical role of mitochondrial dysfunction in the pathological mechanisms of neurodegenerative disorders, particularly Parkinson's disease (PD), is well established. Compelling evidence indicates that Parkinson's proteins (e.g., α-synuclein, Parkin, PINK1, DJ-1, and LRRK2) are associated with mitochondrial dysfunction and oxidative stress in PD. Significantly, there is a possible central role of alpha-synuclein (α-Syn) in the occurrence of mitochondrial dysfunction and oxidative stress by the mediation of different signaling pathways. Also, tau, traditionally considered as the main component of neurofibrillary tangles, aggregates and amplifies the neurotoxic effects on mitochondria by interacting with α-Syn. Moreover, oxidative stress caused by mitochondrial dysfunction favors assembly of both α-Syn and tau and also plays a key role in the formation of protein aggregates. In this review, we provide an overview of the relationship between these two pathological proteins and mitochondrial dysfunction in PD, and also summarize the underlying mechanisms in the interplay of α-Syn aggregation and phosphorylated tau targeting the mitochondria, to find new strategies to prevent PD processing.

Topics: alpha-Synuclein; Humans; Mitochondria; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease

Synucleinopathies are a group of neurodegenerative disorders caused by the misfolding and self-templating of the protein α-synuclein, or the formation of α-synuclein prions. Each disorder differs by age of onset, presenting clinical symptoms, α-synuclein inclusion morphology, and neuropathological distribution. Explaining this disease-specific variability, the strain hypothesis postulates that each prion disease is encoded by a distinct conformation of the misfolded protein, and therefore, each synucleinopathy is caused by a unique α-synuclein structure. This review discusses the current data supporting the role of α-synuclein strains in disease heterogeneity. Several in vitro and in vivo models exist for evaluating strain behavior, however, as the focus of this article is to compare strains across synucleinopathy patients, our discussion predominantly focuses on the two models most commonly used for this purpose: the α-syn140*A53T-YFP cell line and the TgM83

Topics: alpha-Synuclein; Animals; Cell Line; Humans; Mice; Mice, Knockout; Mice, Transgenic; Neurodegenerative Diseases; Synucleinopathies

The ubiquitin-proteasome system is the major pathway for the maintenance of protein homeostasis. Its inhibition causes accumulation of ubiquitinated proteins; this accumulation has been associated with several of the most common neurodegenerative diseases. Several genetic factors have been identified for most neurodegenerative diseases, however, most cases are considered idiopathic, thus making the study of the mechanisms of protein accumulation a relevant field of research. It is often mentioned that the biggest risk factor for neurodegenerative diseases is aging, and several groups have reported an age-related alteration of the expression of some of the 26S proteasome subunits and a reduction of its activity. Proteasome subunits interact with proteins that are known to accumulate in neurodegenerative diseases such as α-synuclein in Parkinson's, tau in Alzheimer's, and huntingtin in Huntington's diseases. These interactions have been explored for several years, but only until recently, we are beginning to understand them. In this review, we discuss the known interactions, the underlying patterns, and the phenotypes associated with the 26S proteasome subunits in the etiology and progression of neurodegenerative diseases where there is evidence of proteasome involvement. Special emphasis is made in reviewing proteasome subunits that interact with proteins known to have an age-related altered expression or to be involved in neurodegenerative diseases to explore key effectors that may trigger or augment their progression. Interestingly, while the causes of age-related reduction of some of the proteasome subunits are not known, there are specific relationships between the observed neurodegenerative disease and the affected proteasome subunits.

Topics: alpha-Synuclein; Animals; Humans; Huntingtin Protein; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Protein Aggregation, Pathological; Protein Binding; Protein Subunits; tau Proteins; Ubiquitin

Parkinson's disease (PD) is a complex, age-related, neurodegenerative disease whose pathogenesis remains incompletely understood. Here, we give an overview of the progress that has been made over the past four decades in our understanding of this disorder. We review the role of mitochondria, environmental toxicants, alpha-synuclein and neuroinflammation in the development of PD. We also discuss more recent data from genetics, which strongly support the endosomal-lysosomal pathways and mitophagy as being central to PD. Finally, we discuss the emerging role of the gut-brain axis as a modulator of PD progression. This article is intended to provide a comprehensive, general and practical review of PD pathogenesis for the general neurologist.

Topics: alpha-Synuclein; Brain; Humans; Mitochondria; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is a progressive neurodegenerative disease where dopaminergic neurons in the substantia nigra are lost, resulting in a decrease in striatal dopamine and, consequently, motor control. Dopaminergic degeneration is associated with the appearance of Lewy bodies, which contain membrane structures and proteins, including α-synuclein (α-Syn), in surviving neurons. PD displays a multifactorial pathology and develops from interactions between multiple elements, such as age, environmental conditions, and genetics. Mutations in the GBA1 gene represent one of the major genetic risk factors for PD. This gene encodes an essential lysosomal enzyme called β-glucocerebrosidase (GCase), which is responsible for degrading the glycolipid glucocerebroside into glucose and ceramide. GCase can generate glucosylated cholesterol via transglucosylation and can also degrade the sterol glucoside. Although the molecular mechanisms that predispose an individual to neurodegeneration remain unknown, the role of cholesterol in PD pathology deserves consideration. Disturbed cellular cholesterol metabolism, as reflected by accumulation of lysosomal cholesterol in GBA1-associated PD cellular models, could contribute to changes in lipid rafts, which are necessary for synaptic localization and vesicle cycling and modulation of synaptic integrity. α-Syn has been implicated in the regulation of neuronal cholesterol, and cholesterol facilitates interactions between α-Syn oligomers. In this review, we integrate the results of previous studies and describe the cholesterol landscape in cellular homeostasis and neuronal function. We discuss its implication in α-Syn and Lewy body pathophysiological mechanisms underlying PD, focusing on the role of GCase and cholesterol. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Cholesterol; Glucosylceramidase; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease

Neurodegenerative diseases are characterised by progressive damage to the nervous system including the selective loss of vulnerable populations of neurons leading to motor symptoms and cognitive decline. Despite millions of people being affected worldwide, there are still no drugs that block the neurodegenerative process to stop or slow disease progression. Neuronal death in these diseases is often linked to the misfolded proteins that aggregate within the brain (proteinopathies) as a result of disease-related gene mutations or abnormal protein homoeostasis. There are two major degradation pathways to rid a cell of unwanted or misfolded proteins to prevent their accumulation and to maintain the health of a cell: the ubiquitin-proteasome system and the autophagy-lysosomal pathway. Both of these degradative pathways depend on the modification of targets with ubiquitin. Aging is the primary risk factor of most neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. With aging there is a general reduction in proteasomal degradation and autophagy, and a consequent increase of potentially neurotoxic protein aggregates of β-amyloid, tau, α-synuclein, SOD1 and TDP-43. An often over-looked yet major component of these aggregates is ubiquitin, implicating these protein aggregates as either an adaptive response to toxic misfolded proteins or as evidence of dysregulated ubiquitin-mediated degradation driving toxic aggregation. In addition, non-degradative ubiquitin signalling is critical for homoeostatic mechanisms fundamental for neuronal function and survival, including mitochondrial homoeostasis, receptor trafficking and DNA damage responses, whilst also playing a role in inflammatory processes. This review will discuss the current understanding of the role of ubiquitin-dependent processes in the progressive loss of neurons and the emergence of ubiquitin signalling as a target for the development of much needed new drugs to treat neurodegenerative disease.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Autophagy; Cell Death; Humans; Lysosomes; Mitochondria; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Signal Transduction; tau Proteins; Ubiquitin

Lewy bodies (LBs) are α-synuclein (α-syn)-rich intracellular inclusions that are an important pathological hallmark of Parkinson disease and several other neurodegenerative diseases. Increasing evidence suggests that the aggregation of α-syn has a central role in LB formation and is one of the key processes that drive neurodegeneration and pathology progression in Parkinson disease. However, little is known about the mechanisms underlying the formation of LBs, their biochemical composition and ultrastructural properties, how they evolve and spread with disease progression, and their role in neurodegeneration. In this Review, we discuss current knowledge of α-syn pathology, including the biochemical, structural and morphological features of LBs observed in different brain regions. We also review the most used cellular and animal models of α-syn aggregation and pathology spreading in relation to the extent to which they reproduce key features of authentic LBs. Finally, we provide important insights into molecular and cellular determinants of LB formation and spreading, and highlight the critical need for more detailed and systematic characterization of α-syn pathology, at both the biochemical and structural levels. This would advance our understanding of Parkinson disease and other neurodegenerative diseases and allow the development of more-reliable disease models and novel effective therapeutic strategies.

Topics: alpha-Synuclein; Animals; Brain; Humans; Lewy Bodies; Neurodegenerative Diseases

Parkinson's disease (PD) is the second most common neurodegenerative disease. Currently, PD has no treatment. The neuronal protein α-synuclein (αS) plays an important role in PD. However, the molecular mechanisms governing its physiological and pathological roles are not fully understood. It is becoming widely acknowledged that the biological roles of αS involve interactions with biological membranes. In these biological processes there is a fine-tuned interplay between lipids affecting the properties of αS and αS affecting lipid metabolism, αS binding to membranes, and membrane damage. In this review, the intricate interactions between αS and membranes will be reviewed and a discussion of the relationship between αS and neuronal membrane structural plasticity in health and disease will be made. It is proposed that in healthy neurons the conformational flexibilities of αS and the neuronal membranes are coupled to assist the physiological roles of αS. However, in circumstances where their conformational flexibilities are decreased or uncoupled, there is a shift toward cell toxicity. Strategies to modulate toxic αS-membrane interactions are potential approaches for the development of new therapies for PD. Future work using specific αS molecular species as well as membranes with specific physicochemical properties should widen our understanding of the intricate biological roles of αS which, in turn, would propel the development of new strategies for the treatment of PD.

Topics: alpha-Synuclein; Cell Membrane; Humans; Molecular Conformation; Neurodegenerative Diseases; Neurons

A number of neurodegenerative diseases including prion diseases, tauopathies and synucleinopathies exhibit multiple clinical phenotypes. A diversity of clinical phenotypes has been attributed to the ability of amyloidogenic proteins associated with a particular disease to acquire multiple, conformationally distinct, self-replicating states referred to as strains. Structural diversity of strains formed by tau, α-synuclein or prion proteins has been well documented. However, the question how different strains formed by the same protein elicit different clinical phenotypes remains poorly understood. The current article reviews emerging evidence suggesting that posttranslational modifications are important players in defining strain-specific structures and disease phenotypes. This article put forward a new hypothesis referred to as substrate selection hypothesis, according to which individual strains selectively recruit protein isoforms with a subset of posttranslational modifications that fit into strain-specific structures. Moreover, it is proposed that as a result of selective recruitment, strain-specific patterns of posttranslational modifications are formed, giving rise to unique disease phenotypes. Future studies should define whether cell-, region- and age-specific differences in metabolism of posttranslational modifications play a causative role in dictating strain identity and structural diversity of strains of sporadic origin.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Phenotype; Prion Proteins; Protein Conformation; Protein Processing, Post-Translational; Substrate Specificity; Synucleinopathies; tau Proteins; Tauopathies

The accumulation and propagation in the brain of misfolded proteins is a pathological hallmark shared by many neurodegenerative diseases such as Alzheimer's disease (Aβ and tau), Parkinson's disease (α-synuclein), and prion disease (prion protein). Currently, there is no epidemiological evidence to suggest that neurodegenerative disorders are infectious, apart from prion diseases. However, there is an increasing body of evidence from experimental models to suggest that other pathogenic proteins such as Aβ and tau can propagate in vivo and in vitro in a prion-like mechanism, inducing the formation of misfolded protein aggregates such as amyloid plaques and neurofibrillary tangles. Such similarities have raised concerns that misfolded proteins, other than the prion protein, could potentially transmit from person-to-person as rare events after lengthy incubation periods. Such concerns have been heightened following a number of recent reports of the possible inadvertent transmission of Aβ pathology via medical and surgical procedures. This review will provide a historical perspective on the unique transmissible nature of prion diseases, examining their impact on public health and the ongoing concerns raised by this rare group of disorders. Additionally, this review will provide an insight into current evidence supporting the potential transmissibility of other pathogenic proteins associated with more common neurodegenerative disorders and the potential implications for public health.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Creutzfeldt-Jakob Syndrome; Humans; Mice; Neurodegenerative Diseases; Phenotype; Plaque, Amyloid; Prion Diseases; Prion Proteins; Prions; Protein Denaturation; Protein Folding; tau Proteins

Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer,

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Animals; Diabetes Mellitus, Type 2; Humans; Islet Amyloid Polypeptide; Models, Molecular; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregation, Pathological; Proteostasis Deficiencies; Superoxide Dismutase-1; tau Proteins

Electrochemical biosensors have been adopted into a wide range of applications in the study of biometal-protein interactions in neurodegenerative diseases. Transition metals such as zinc, copper, and iron that are significant to biological functions have been shown to have strong implications in the progressive neural degeneration in Alzheimer's disease (AD), Parkinson's disease (PD), and prion protein diseases. This review presents a summative examination of the progress made in the design, fabrication, and applications of electrochemical biosensors in recent literature at understanding the metal-protein interactions in neurodegenerative diseases. The focus will be drawn on disease-causing biomarkers such as amyloid-β (Aβ) and tau proteins for AD, α-synuclein (α-syn) for PD, and prion proteins (PrP). Topics such as the use of electrochemical biosensing in monitoring biometal-induced conformational changes, elucidation of complexation motifs, production of reactive oxygen species (ROS) as well as the influence on downstream biomolecular interactions will be discussed. Major results and important concepts presented in these studies will be summarized in the hope to spark inspiration for the next generation of electrochemical sensors.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biosensing Techniques; Humans; Neurodegenerative Diseases; Trace Elements

Parkinson's disease (PD) is a progressive neurodegenerative disease with motor symptoms, such as tremor, akinesia/bradykinesia, rigidity and postural instability due to a loss of nigrostriatal dopaminergic neurons; PD patients also exhibit non-motor symptoms, such as hyposmia, orthostatic hypotension and constipation, which precede motor symptoms. Pathologically, Lewy bodies and neurites, which contains α-synuclein, are observed in the central and peripheral nervous system. To date, it is hypothesized that PD pathology appears first in the olfactory bulb and the enteric nervous system, and propagates progressively through the substantia nigra to finally reach the cerebral cortex. Major medications at present are nosotropic treatments to improve motor dysfunction in PD. Therefore, development of disease-modifying drug is required to slow or prevent PD progression. Astrocytes are known to play an important role in the maintenance of the neuronal environment and exert neuroprotective effects by production of antioxidants and neurotrophic factors and clearing toxic molecules. In the previous study, we demonstrated that astrocytes produced antioxidative molecules metallothionein (MT)-1/2 in response to oxidative stress and protected dopaminergic neurons against oxidative stress. MTs are cysteine-rich proteins possessing antioxidative properties. MTs bind to metals such as zinc (Zn) and copper (Cu) and function in metal homeostasis and detoxification; MTs regulate Zn-mediated transcriptional activation of various genes. Recently, it is reported that MTs prevent Cu-induced aggregation of α-synuclein. In this article, we review a new therapeutic strategy of neuroprotection in PD by targeting MTs in astrocytes.

Topics: alpha-Synuclein; Astrocytes; Carrier Proteins; Humans; Neurodegenerative Diseases; Parkinson Disease

Misfolded proteins, inflammation, and vascular alterations are common pathological hallmarks of neurodegenerative diseases. Alpha-synuclein is a small synaptic protein that was identified as a major component of Lewy bodies and Lewy neurites in the brain of patients affected by Parkinson's disease (PD), Lewy body dementia (LBD), and other synucleinopathies. It is mainly involved in the regulation of synaptic vesicle trafficking but can also control mitochondrial/endoplasmic reticulum (ER) homeostasis, lysosome/phagosome function, and cytoskeleton organization. Recent evidence supports that the pathological forms of α-synuclein can also reduce the release of vasoactive and inflammatory mediators from endothelial cells (ECs) and modulates the expression of tight junction (TJ) proteins important for maintaining the blood-brain barrier (BBB). This hints that α-synuclein deposition can affect BBB integrity. Border associated macrophages (BAMs) are brain resident macrophages found in association with the vasculature (PVMs), meninges (MAMs), and choroid plexus (CPMs). Recent findings indicate that these cells play distinct roles in stroke and neurodegenerative disorders. Although many studies have addressed how α-synuclein may modulate microglia, its effect on BAMs has been scarcely investigated. This review aims at summarizing the main findings supporting how α-synuclein can affect ECs and/or BAMs function as well as their interplay and effect on other cells in the brain perivascular environment in physiological and pathological conditions. Gaps of knowledge and new perspectives on how this protein can contribute to neurodegeneration by inducing BBB homeostatic changes in different neurological conditions are highlighted.

Topics: alpha-Synuclein; Animals; Biomarkers; Blood-Brain Barrier; Brain; Cell Communication; Central Nervous System; Disease Susceptibility; Endothelial Cells; Gene Expression Regulation; Humans; Microglia; Neurodegenerative Diseases

Parkinson's disease (PD) is one of the most critical disorders of the elderly and strongly associated with increased disability, and reduced quality of life. PD is a progressive neurodegenerative disease affecting more than six million people worldwide. Evaluation of clinical manifestations, as well as movement disorders by a neurologist and some routine laboratory tests are the most important diagnostic methods for PD. However, routine and old methods have several disadvantages and limitations such as low sensitivity and selectivity, high cost, and need for advanced equipment. Biosensors technology opens up new diagnoses approach for PD with the use of a new platform that allows reliable, repeatable, and multidimensional identification to be made with minimal problem and discomfort for patients. For instance, biosensing systems can provide promising tools for PD treatment and monitoring. Amongst biosensor technology, electrochemical techniques have been at the frontline of this progress, thanks to the developments in material science, such as gold nanoparticles (AuNPs), quantum dots (QDs), and carbon nanotubes (CNTs). This paper evaluates the latest progress in electrochemical and optical biosensors for PD diagnosis.

Topics: Aged; alpha-Synuclein; Biosensing Techniques; Gold; Humans; Metal Nanoparticles; Nanotubes, Carbon; Neurodegenerative Diseases; Parkinson Disease; Quality of Life

Parkinson's disease is one of the most common neurodegenerative disorders worldwide, characterized by a progressive loss of dopaminergic neurons mainly localized in the

Topics: alpha-Synuclein; Animals; DNA-Binding Proteins; DNA, Mitochondrial; Dopaminergic Neurons; Genome-Wide Association Study; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Mitochondria; Neurodegenerative Diseases; Neurons; Organelle Biogenesis; Oxidative Stress; Parkinson Disease; Pars Compacta; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Phosphorylation; Protein Deglycase DJ-1; Protein Kinases; Transcription Factors; Ubiquitin-Protein Ligases; Vesicular Transport Proteins

Parkinson's disease (PD) is a common neurodegenerative disease characterized by a progressive loss of fine motor function that impacts 1-2 out of 1,000 people. PD occurs predominately late in life and lacks a definitive biomarker for early detection. Recent cross-disciplinary progress has implicated the gut as a potential origin of PD pathogenesis. The gut-origin hypothesis has motivated research on gut PD pathology and transmission to the brain, especially during the prodromal stage (10-20 years before motor symptom onset). Early findings have revealed several possible triggers for Lewy pathology - the pathological hallmark of PD - in the gut, suggesting that microbiome and epithelial interactions may play a greater than appreciated role. But the mechanisms driving Lewy pathology and gut-brain transmission in PD remain unknown. Development of artificial α-Synuclein aggregates (α-Syn preformed fibrils) and animal disease models have recapitulated features of PD progression, enabling for the first time, controlled investigation of the gut-origin hypothesis. However, the role of specific cells in PD transmission, such as neurons, remains limited and requires in vitro models for controlled evaluation and perturbation. Human cell populations, three-dimensional organoids, and microfluidics as discovery platforms inch us closer to improving existing treatment for patients by providing platforms for discovery and screening. This review includes a discussion of PD pathology, conventional treatments, in vivo and in vitro models, and future directions. STATEMENT OF SIGNIFICANCE: Parkinson's Disease remains a common neurodegenerative disease with palliative versus causal treatments. Recently, the gut-origin hypothesis, where Parkinson's disease is thought to originate and spread from the gut to the brain, has gained traction as a field of investigation. However, despite the wealth of studies and innovative approaches to accelerate the field, there remains a need for in vitro tools to enable fundamental biological understanding of disease progression, and compound screening and efficacy. In this review, we present a historical perspective of Parkinson's Disease pathogenesis, detection, and conventional therapy, animal and human models investigating the gut-origin hypothesis, in vitro models to enable controlled discovery, and future outlooks for this blossoming field.

Topics: alpha-Synuclein; Animals; Brain; Humans; Neurodegenerative Diseases; Neurons; Parkinson Disease

Professor Kurt Jellinger is well known for his seminal work on the neuropathology of age-associated neurodegenerative disorders, particularly Lewy body diseases. However, it is less well known that he also contributed important insights into the neuropathological features of several paediatric neurometabolic diseases, including Alpers-Huttenlocher syndrome, a syndrome of mitochondrial disease caused by POLG mutations, and infantile neuroaxonal dystrophy, a phenotype resulting from PLA2G6 mutations. Despite these rare diseases occurring in early life, they share many important pathological overlaps with age-associated Lewy body disease, particularly dysregulation of α-synuclein. In this review, we describe several neurometabolic diseases linked to Lewy body disease mechanisms, and discuss the wider context to pathological overlaps between neurometabolic and Lewy body diseases. In particular, we will focus on how understanding disease mechanisms in neurometabolic disorders with dysregulated α-synuclein may generate insights into predisposing factors for α-synuclein aggregation in idiopathic Lewy body diseases.

Topics: alpha-Synuclein; Humans; Lewy Body Disease; Neurodegenerative Diseases; Phenotype; Rare Diseases

The potential to treat neurodegenerative diseases (NDs) of the major bioactive compound of green tea, epigallocatechin-3-gallate (EGCG), is well documented. Numerous findings now suggest that EGCG targets protein misfolding and aggregation, a common cause and pathological mechanism in many NDs. Several studies have shown that EGCG interacts with misfolded proteins such as amyloid beta-peptide (Aβ), linked to Alzheimer's disease (AD), and α-synuclein, linked to Parkinson's disease (PD). To date, NDs constitute a serious public health problem, causing a financial burden for health care systems worldwide. Although current treatments provide symptomatic relief, they do not stop or even slow the progression of these devastating disorders. Therefore, there is an urgent need to develop effective drugs for these incurable ailments. It is expected that targeting protein misfolding can serve as a therapeutic strategy for many NDs since protein misfolding is a common cause of neurodegeneration. In this context, EGCG may offer great potential opportunities in drug discovery for NDs. Therefore, this review critically discusses the role of EGCG in NDs drug discovery and provides updated information on the scientific evidence that EGCG can potentially be used to treat many of these fatal brain disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Catechin; Drug Discovery; Humans; Molecular Targeted Therapy; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregates; Protein Folding; Tea

Biomarkers for neurodegenerative diseases are needed to improve the diagnostic workup in the clinic but also to facilitate the development and monitoring of effective disease-modifying therapies. Positron emission tomography methods detecting amyloid-β and tau pathology in Alzheimer's disease have been increasingly used to improve the design of clinical trials and observational studies. In recent years, easily accessible and cost-effective blood-based biomarkers detecting the same Alzheimer's disease pathologies have been developed, which might revolutionize the diagnostic workup of Alzheimer's disease globally. Relevant biomarkers for α-synuclein pathology in Parkinson's disease are also emerging, as well as blood-based markers of general neurodegeneration and glial activation. This review presents an overview of the latest advances in the field of biomarkers for neurodegenerative diseases. Future directions are discussed regarding implementation of novel biomarkers in clinical practice and trials.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease; Positron-Emission Tomography; tau Proteins

Intrinsic disorder is a natural feature of polypeptide chains, resulting in the lack of a defined three-dimensional structure. Conformational changes in intrinsically disordered regions of a protein lead to unstable β-sheet enriched intermediates, which are stabilized by intermolecular interactions with other β-sheet enriched molecules, producing stable proteinaceous aggregates. Upon misfolding, several pathways may be undertaken depending on the composition of the amino acidic string and the surrounding environment, leading to different structures. Accumulating evidence is suggesting that the conformational state of a protein may initiate signalling pathways involved both in pathology and physiology. In this review, we will summarize the heterogeneity of structures that are produced from intrinsically disordered protein domains and highlight the routes that lead to the formation of physiological liquid droplets as well as pathogenic aggregates. The most common proteins found in aggregates in neurodegenerative diseases and their structural variability will be addressed. We will further evaluate the clinical relevance and future applications of the study of the structural heterogeneity of protein aggregates, which may aid the understanding of the phenotypic diversity observed in neurodegenerative disorders.

Topics: alpha-Synuclein; Amyloid; Humans; Intrinsically Disordered Proteins; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; Protein Conformation, beta-Strand; tau Proteins

Recently, genome-editing technology like clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 has improved the translational gap in the treatments mediated through gene therapy. The advantages of the CRISPR system, such as, work in the living cells and tissues, candidate this technique for the employing in experiments and the therapy of central nervous system diseases. Parkinson's disease (PD) is a widespread, disabling, neurodegenerative disease induced by dopaminergic neuron loss and linked to progressive motor impairment. Pathophysiological basis knowledge of PD has modified the PD classification model and expresses in the sporadic and familial types. Analyses of the earliest genetic linkage have shown in PD the inclusion of synuclein alpha (SNCA) genomic duplication and SNCA mutations in the familial types of PD pathogenesis. This review analyzes the structure, development, and function in genome editing regulated through the CRISPR/Cas9. Also, it explains the genes associated with PD pathogenesis and the appropriate modifications to favor PD. This study follows the direction by understanding the PD linking analyses in which the CRISPR technique is applied. Finally, this study explains the limitations and future trends of CRISPR service in relation to the genome-editing process in PD patients' induced pluripotent stem cells.

Topics: alpha-Synuclein; CRISPR-Cas Systems; Gene Editing; Humans; Neurodegenerative Diseases; Parkinson Disease

Pure autonomic failure (PAF) is a peripheral autonomic neurodegenerative disease caused by alpha-synuclein deposition that is predominantly confined to peripheral autonomic neurons. Patients present with insidious features of autonomic failure that have a chronic course.In this review, we highlight the features of PAF, the differentiating features from other autonomic neuropathies, the diagnostic tests, and the predictors for conversion to a central synucleinopathy.. Natural history studies have defined the predictors for and rate of conversion to a central alpha-synucleinopathy. Skin immunohistochemistry techniques and demonstration of length-dependent neuronal loss of both somatic and autonomic small fiber nerves, and intraneural phosphorylated synuclein deposition provide diagnostic biomarkers. In the future, diagnosis maybe supported by measuring cerebrospinal fluid alpha-synuclein oligomers using techniques, such as protein misfolding cyclic amplification assay and real-time quaking-induced conversion.. PAF is a sporadic peripheral autonomic neurodegenerative disease that belongs to the group of disorders known as alpha-synucleinopathies. Peripheral autonomic manifestations are similar to those seen in other autonomic neuropathies, particularly, diabetic autonomic neuropathy, amyloid polyneuropathy, and autoimmune autonomic neuropathies. Novel diagnostic procedures like skin immunohistochemistry for alpha-synuclein, and protein amplification techniques are being investigated to provide an earlier and more specific diagnosis. A substantial number of PAF patients' phenoconvert to a central alpha-synucleinopathy.

Topics: alpha-Synuclein; Autonomic Nervous System Diseases; Diagnosis, Differential; Humans; Neurodegenerative Diseases; Peripheral Nervous System Diseases; Pure Autonomic Failure; Synucleinopathies

Parkinson's disease (PD) is the second most common neurodegenerative disease amongst the middle‑aged and elderly populations. Several studies have confirmed that the microbiota‑gut‑brain axis (MGBA) serves a key role in the pathogenesis of PD. Changes to the gastrointestinal microbiome (GM) cause misfolding and abnormal aggregation of α‑synuclein (α‑syn) in the intestine. Abnormal α‑syn is not eliminated via physiological mechanisms and is transported into the central nervous system (CNS) via the vagus nerve. The abnormal levels of α‑syn aggregate in the substantia nigra pars compacta, not only leading to the formation of eosinophilic Lewis Bodies in the cytoplasm and mitochondrial dysfunction in dopaminergic (DA) neurons, but also leading to the stimulation of an inflammatory response in the microglia. These pathological changes result in an increase in oxidative stress (OS), which triggers nerve cell apoptosis, a characteristic of PD. This increase in OS further oxidizes and intensifies abnormal aggregation of α‑syn, eventually forming a positive feedback loop. The present review discusses the abnormal accumulation of α‑syn in the intestine caused by the GM changes and the increased levels of α‑syn transport to the CNS via the MGBA, resulting in the loss of DA neurons and an increase in the inflammatory response of microglial cells in the brain of patients with PD. In addition, relevant clinical therapeutic strategies for improving the GM and reducing α‑syn accumulation to relieve the symptoms and progression of PD are described.

Topics: Aged; alpha-Synuclein; Bacteria; Brain; Brain-Gut Axis; Disease Progression; Dopaminergic Neurons; Dysbiosis; Gastrointestinal Microbiome; Humans; Microglia; Middle Aged; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease

Neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, are characterized by the aggregation of misfolded proteins, including Aβ, tau and α-synuclein. It is well recognized that these misfolded proteins are able to self-propagate and spread throughout the nervous system and cause neuronal injury in a way that resembles prion disease. These disease-specific misfolded proteins demonstrate unique features, including the seeding barrier, the conformational memory effect, strain selection and strain evolution, based on the presence of various strains. However, the accurate definition of the term strain remains to be clarified. Here, a clear interpretation is proposed by a retrospective of its history in prion research and the recent progress in neurodegeneration research. Furthermore, the causes contributing to the genesis of various strains are also summarized. Deeper insight into strains helps us to understand the phenomena we observe in this field and it also enlightens us on the elusive mechanisms and management of neurodegeneration.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Neurodegenerative Diseases; Prions; Protein Aggregation, Pathological; Protein Folding; tau Proteins

Abnormal protein aggregation has been linked to many neurodegenerative diseases, including Parkinson's disease (PD). The main pathological hallmark of PD is the formation of Lewy bodies (LBs) and Lewy neurites, both of which contain the presynaptic protein alpha-synuclein (α-syn). Under normal conditions, native α-syn exists in a soluble unfolded state but undergoes misfolding and aggregation into toxic aggregates under pathological conditions. Toxic α-syn species, especially oligomers, can cause oxidative stress, membrane penetration, synaptic and mitochondrial dysfunction, as well as other damage, leading to neuronal death and eventually neurodegeneration. Early diagnosis and treatments targeting PD pathogenesis are urgently needed. Given its critical role in PD, α-syn is an attractive target for the development of both diagnostic tools and effective therapeutics. This review summarizes the progress toward discovering imaging probes and aggregation inhibitors for α-syn. Relevant strategies and techniques in the discovery of α-syn-targeted drugs are also discussed.

Topics: alpha-Synuclein; Animals; Flavonoids; Fluorescent Dyes; Humans; Neurodegenerative Diseases; Positron-Emission Tomography; Protein Aggregates; Tomography, Emission-Computed, Single-Photon

In vitro conversion assays, including real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA) techniques, were first developed to study the conversion process of the prion protein to its misfolded, disease-associated conformation. The intrinsic property of prion proteins to propagate their misfolded structure was later exploited to detect subfemtogram quantities of the misfolded protein present in tissues and fluids from humans and animals with transmissible spongiform encephalopathies. Currently, conversion assays are used clinically as sensitive and specific diagnostic tools for antemortem diagnosis of prion disease.. In vitro conversion assays are now being applied to the development of diagnostics for related neurodegenerative diseases, including detection of misfolded α-synuclein in Parkinson disease, misfolded amyloid-β in Alzheimer disease, and misfolded tau in Pick disease. Like the predicate prion protein in vitro conversion diagnostics, these assays exploit the ability of endogenously misfolded proteins to induce misfolding and aggregation of their natively folded counterpart in vitro. This property enables biomarker detection of the underlying protein pathology. Herein, we review RT-QuIC and PMCA for (a) prion-, (b) α-synuclein-, (c) amyloid-β-, and (d) tau-opathies.. Although already in routine clinical use for the detection of transmissible spongiform encephalopathies, in vitro conversion assays for other neurodegenerative disorders require further development and evaluation of diagnostic performance before consideration for clinical implementation.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Biological Assay; Biomarkers; Clinical Chemistry Tests; Humans; Neurodegenerative Diseases; Prion Diseases; Prion Proteins; Protein Folding; tau Proteins

A neuropathological hallmark of most neurodegenerative diseases is the appearance of characteristic inclusions composed of misfolded proteins in brains of patients. Increasing evidence shows that aggregation-prone proteins such as tau, α-synuclein and TDP-43 are accumulated in a seed-dependent and self-templating manner in vitro and in vivo, suggesting that pathological protein aggregates found in these diseases function like abnormal prion protein. Indeed, insoluble tau and α-synuclein aggregates are transferred from cell to cell both in vitro and in vivo, indicating that prion-like propagation of aberrant protein aggregates may play a key role in the pathogenesis of most neurodegenerative diseases. Here, we will review the prion-like properties of TDP-43, and discuss the molecular mechanisms underlying the propagation of these accumulated proteins. The idea that aberrant protein aggregates propagate in a prion-like manner between cells opens up the possibility of novel therapeutic strategies to block the spread of these aggregates throughout the brain.

Topics: alpha-Synuclein; Brain; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Prions

Alzheimer's disease (AD) is characterized neuropathologically by progressive neurodegeneration and by the presence of amyloid plaques and neurofibrillary tangles. These plaques and tangles are composed, respectively, of amyloid-beta (Aβ) and tau proteins. While long recognized as hallmarks of AD, it remains unclear what causes the formation of these insoluble deposits. One theory holds that prion-like templated misfolding of Aβ and tau induces these proteins to form pathological aggregates, and propagation of this misfolding causes the stereotyped progression of pathology commonly seen in AD. Supporting this theory, numerous studies have been conducted in which aggregated Aβ, tau, or α-synuclein is injected intracerebrally into pathology-free host animals, resulting in robust formation of pathology. Here, we review this literature, focusing on in vivo intracerebral seeding of Aβ and tau in mice. We compare the results of these experiments to what is known about the seeding and spread of α-synuclein pathology, and we discuss how this research informs our understanding of the factors underlying the onset, progression, and outcomes of proteinaceous pathologies.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Mice; Neurodegenerative Diseases; Prion Diseases; tau Proteins

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Although the standard dopamine replacement therapy can alleviate motor symptoms, presently there is no available treatment to stop or reverse disease progression. Thus, there is an urgent need for the development of novel disease-modifying therapies to prevent the accumulation of cytotoxic α-synuclein (αS), a protein involved in PD pathogenesis, in the nervous system. Furthermore, emerging evidence suggests that the toxic αS species can move from one cell to another, thereby affecting the normal physiological state of the neighboring cells in a prion-like manner. The transmissible, extracellular αS is considered to be an ideal target for the disease-modifying treatments including antibody-based therapy. In this review, we will describe the molecular structure and functions of αS, its relevance to PD pathogenesis, and will discuss the current status and future perspectives of disease-modifying strategies targeting αS in PD.

Topics: alpha-Synuclein; Dopamine; Humans; Neurodegenerative Diseases; Parkinson Disease; Prions

Patients with idiopathic REM-sleep behavior disorder (iRBD) are at substantial risk of progressive neurodegenerative disease of α-synuclein pathology. Longitudinal studies have demonstrated that abnormal α-synuclein deposition occurs early in the course of disease and may precede the appearance of motor symptoms by several decades. This provides rationale for the use of a reliable biomarker to both follow disease progression and to assess treatment response, once disease-modifying treatments become available. Tissue α-synuclein has emerged as a promising candidate, however the utility of α-synuclein detection in tissues accessible to biopsy in iRBD remains unclear. This article summarizes the current literature on the role of tissue biopsy in iRBD, with specific focus on its potential role as a biomarker of disease progression and its role in future clinical trials.

Topics: alpha-Synuclein; Biomarkers; Biopsy; Disease Progression; Humans; Neurodegenerative Diseases; REM Sleep Behavior Disorder; Skin

Most neurodegenerative diseases are characterized by the intracellular or extracellular aggregation of misfolded proteins such as amyloid-β and tau in Alzheimer disease, α-synuclein in Parkinson disease, and TAR DNA-binding protein 43 in amyotrophic lateral sclerosis. Accumulating evidence from both human studies and disease models indicates that intercellular transmission and the subsequent templated amplification of these misfolded proteins are involved in the onset and progression of various neurodegenerative diseases. The misfolded proteins that are transferred between cells are referred to as 'pathological seeds'. Recent studies have made exciting progress in identifying the characteristics of different pathological seeds, particularly those isolated from diseased brains. Advances have also been made in our understanding of the molecular mechanisms that regulate the transmission process, and the influence of the host cell on the conformation and properties of pathological seeds. The aim of this Review is to summarize our current knowledge of the cell-to-cell transmission of pathological proteins and to identify key questions for future investigation.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Axonal Transport; Brain; Cell Communication; DNA-Binding Proteins; Endocytosis; Exosomes; Genetic Predisposition to Disease; Humans; Huntingtin Protein; Huntington Disease; Membrane Fusion; Nanotubes; Neurodegenerative Diseases; Neuroglia; Neurons; Parkinson Disease; Protein Aggregation, Pathological; Protein Transport; tau Proteins

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), increase as the population ages around the world. Environmental factors also play an important role in most cases. Alcohol consumption exists extensively and it acts as one of the environmental factors that promotes these neurodegenerative diseases. The brain is a major target for the actions of alcohol, and heavy alcohol consumption has long been associated with brain damage. Chronic alcohol intake leads to elevated glutamate-induced excitotoxicity, oxidative stress and permanent neuronal damage associated with malnutrition. The relationship and contributing mechanisms of alcohol with these three diseases are different. Epidemiological studies have reported a reduction in the prevalence of Alzheimer's disease in individuals who drink low amounts of alcohol; low or moderate concentrations of ethanol protect against β-amyloid (Aβ) toxicity in hippocampal neurons; and excessive amounts of ethanol increase accumulation of Aβ and Tau phosphorylation. Alcohol has been suggested to be either protective of, or not associated with, PD. However, experimental animal studies indicate that chronic heavy alcohol consumption may have dopamine neurotoxic effects through the induction of Cytochrome P450 2E1 (

Topics: Alcohol Drinking; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Animals; Brain; Cell Line; Disease Progression; Ethanol; Humans; Neurodegenerative Diseases; Neurons; Oxidative Stress; Parkinson Disease; Risk Factors

Neurological disorders such as Alzheimer's disease (AD), Lewy body dementia (LBD), frontotemporal dementia (FTD), and vascular dementia (VCID) have no disease-modifying treatments to date and now constitute a dementia crisis that affects 5 million in the USA and over 50 million worldwide. The most common pathological hallmark of these age-related neurodegenerative diseases is the accumulation of specific proteins, including amyloid beta (Aβ), tau, α-synuclein (α-syn), TAR DNA-binding protein 43 (TDP43), and repeat-associated non-ATG (RAN) peptides, in the intra- and extracellular spaces of selected brain regions. Whereas it remains controversial whether these accumulations are pathogenic or merely a byproduct of disease, the majority of therapeutic research has focused on clearing protein aggregates. Immunotherapies have garnered particular attention for their ability to target specific protein strains and conformations as well as promote clearance. Immunotherapies can also be neuroprotective: by neutralizing extracellular protein aggregates, they reduce spread, synaptic damage, and neuroinflammation. This review will briefly examine the current state of research in immunotherapies against the 3 most commonly targeted proteins for age-related neurodegenerative disease: Aβ, tau, and α-syn. The discussion will then turn to combinatorial strategies that enhance the effects of immunotherapy against aggregating protein, followed by new potential targets of immunotherapy such as aging-related processes.

Topics: Aging; alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Clinical Trials as Topic; Drug Delivery Systems; Gene-Environment Interaction; Humans; Immunologic Factors; Immunotherapy; Neurodegenerative Diseases; tau Proteins

The stereotypical spread of pathological protein inclusions and clinicopathological heterogeneity are well described in neurodegenerative diseases. Accumulating evidence suggests that the former can be attributed to consecutive cell-to-cell transmission of pathological proteins between anatomically connected brain regions, while the latter has been hypothesized to result from the spread of conformationally distinct pathological protein aggregates, or strains. These emerging concepts have dramatically changed our understanding of neurodegenerative diseases. In this review, we first summarize the background and recent findings underpinning these concepts with a focus on two major pathological proteins: tau and α-synuclein. We then discuss their clinical implications for tauopathies and synucleinopathies and propose a working hypothesis for future research.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; tau Proteins; Tauopathies

Cells have developed elaborate quality-control mechanisms for proteins and organelles to maintain cellular homeostasis. Such quality-control mechanisms are maintained by conformational folding via molecular chaperones and by degradation through the ubiquitin-proteasome or autophagy-lysosome system. Accumulating evidence suggests that impaired autophagy contributes to the accumulation of intracellular inclusion bodies consisting of misfolded proteins, which is a hallmark of most neurodegenerative diseases. In addition, genetic mutations in core autophagy-related genes have been reported to be linked to neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Conversely, the pathogenic proteins, such as amyloid β and α-synuclein, are detrimental to the autophagy pathway. Here, we review the recent advances in understanding the relationship between autophagic defects and the pathogenesis of neurodegenerative diseases and suggest autophagy induction as a promising strategy for the treatment of these conditions.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Autophagosomes; Autophagy; Humans; Lysosomes; Neurodegenerative Diseases; Neurons; TOR Serine-Threonine Kinases

The abnormal accumulation of neurotoxic proteins is the typical hallmark of various age-related neurodegenerative disorders (NDDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis and Multiple sclerosis. The anomalous proteins, such as Aβ, Tau in Alzheimer's disease and α-synuclein in Parkinson's disease, perturb the neuronal physiology and cellular homeostasis in the brain thereby affecting the millions of human lives across the globe. Here, ubiquitin proteasome system (UPS) plays a decisive role in clearing the toxic metabolites in cells, where any aberrancy is widely reported to exaggerate the neurodegenerative pathologies. In spite of well-advancement in the ubiquitination research, their molecular markers and mechanisms for target-specific protein ubiquitination and clearance remained elusive. Therefore, this review substantiates the role of UPS in the brain signaling and neuronal physiology with their mechanistic role in the NDD's specific pathogenic protein clearance. Moreover, current and future promising therapies are discussed to target UPS-mediated neurodegeneration for better public health.

Topics: alpha-Synuclein; Alzheimer Disease; Humans; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Signal Transduction; Ubiquitin

α-Synuclein (αsyn) is an abundant brain neuronal protein that can misfold and polymerize to form toxic fibrils coalescing into pathologic inclusions in neurodegenerative diseases, including Parkinson's disease, Lewy body dementia, and multiple system atrophy. These fibrils may induce further αsyn misfolding and propagation of pathologic fibrils in a prion-like process. It is unclear why αsyn initially misfolds, but a growing body of literature suggests a critical role of partial proteolytic processing resulting in various truncations of the highly charged and flexible carboxyl-terminal region. This review aims to 1) summarize recent evidence that disease-specific proteolytic truncations of αsyn occur in Parkinson's disease, Lewy body dementia, and multiple system atrophy and animal disease models; 2) provide mechanistic insights on how truncation of the amino and carboxyl regions of αsyn may modulate the propensity of αsyn to pathologically misfold; 3) compare experiments evaluating the prion-like properties of truncated forms of αsyn in various models with implications for disease progression; 4) assess uniquely toxic properties imparted to αsyn upon truncation; and 5) discuss pathways through which truncated αsyn forms and therapies targeted to interrupt them. Cumulatively, it is evident that truncation of αsyn, particularly carboxyl truncation that can be augmented by dysfunctional proteostasis, dramatically potentiates the propensity of αsyn to pathologically misfold into uniquely toxic fibrils with modulated prion-like seeding activity. Therapeutic strategies and experimental paradigms should operate under the assumption that truncation of αsyn is likely occurring in both initial and progressive disease stages, and preventing truncation may be an effective preventative strategy against pathologic inclusion formation.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Protein Aggregation, Pathological

Neurodegenerative diseases (NDDs), such as Alzheimer's (AD) and Parkinson's (PD), are among the leading causes of lost years of healthy life and exert a great strain on public healthcare systems. Despite being first described more than a century ago, no effective cure exists for AD or PD. Although extensively characterised at the molecular level, traditional neurodegeneration research remains marred by narrow-sense approaches surrounding amyloid β (Aβ), tau, and α-synuclein (α-syn). A systems biology approach enables the integration of multi-omics data and informs discovery of biomarkers, drug targets, and treatment strategies. Here, we present a comprehensive timeline of high-throughput data collection, and associated biotechnological advancements and computational analysis related to AD and PD. We hereby propose that a philosophical change in the definitions of AD and PD is now needed.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Biomarkers; Humans; Neurodegenerative Diseases; Systems Biology; tau Proteins

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

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

It was recently shown (Sampson et al., Elife9, 2020) that an amyloidogenic protein, CsgA, present in E. coli biofilms in the gut can trigger Parkinson's disease in mice. This study emphasizes the possible role of the gut microbiome in modulation (and even initiation) of human neurodegenerative disorders, such as Parkinson's disease. As the CsgA protein was found to accelerate alpha-synuclein (the key amyloidogenic protein in Parkinson's disease) amyloid formation in vitro, this result suggests that also other amyloidogenic proteins from gut bacteria, and even from the diet (such as stable allergenic proteins), may be able to affect human protein conformations and thereby modulate amyloid-related diseases. In this review, we summarize what has been reported in terms of in vitro cross-reactivity studies between alpha-synuclein and other amyloidogenic human and non-human proteins. It becomes clear from the limited data that exist that there is a fine line between acceleration and inhibition, but that cross-reactivity is widespread, and it is more common for other proteins (among the studied cases) to accelerate alpha-synuclein amyloid formation than to block it. It is of high importance to expand investigations of cross-reactivity between amyloidogenic proteins to both reveal underlying mechanisms and links between human diseases, as well as to develop new treatments that may be based on an altered gut microbiome.

Topics: alpha-Synuclein; Amyloid; Amyloidogenic Proteins; Animals; Humans; Neurodegenerative Diseases; Parkinson Disease; Protein Conformation

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

Most common neurodegenerative diseases (NDs) are characterized by deposition of protein aggregates that are resulted from misfolding, dysregulated trafficking, and compromised proteolytic degradation. These proteins exert cellular toxicity to a broad range of brain cells and are found in both neurons and glia. Extracellular monomeric and oligomeric ND-associated proteins are taken up by astrocytes, the most abundant glial cell in the brain. Internalization, intracellular trafficking, processing, and disposal of these proteins are executed by the endosomal-lysosomal system of astrocytes. Endosomal-lysosomal organelles thus mediate the cellular impact and metabolic fate of these toxic protein species. Given the indispensable role of astrocytes in brain metabolic homeostasis, the endosomal-lysosomal processing of these proteins plays a fundamental role in altering the trajectory of neurodegeneration. This review aims at summarizing the mounting evidence that has established the essential role of astrocytic endosomal-lysosomal organelles in the processing of amyloid precursor proteins, Apolipoprotein E (ApoE), tau, alpha synuclein, and huntingtin, which are associated with NDs such as Alzheimer's, Parkinson's, and Huntington diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Apolipoproteins E; Astrocytes; Brain; Endosomes; Humans; Huntingtin Protein; Lysosomes; Neurodegenerative Diseases; Neurons; tau Proteins

In neuronal cells, tau is a microtubule-associated protein placed in axons and alpha synuclein is enriched at presynaptic terminals. They display a propensity to form pathologic aggregates, which are considered the underlying cause of Alzheimer's and Parkinson's diseases. Their functional impairment induces loss of axonal transport, synaptic and mitochondrial disarray, leading to a "dying back" pattern of degeneration, which starts at the periphery of cells. In addition, pathologic spreading of alpha-synuclein from the peripheral nervous system to the brain through anatomical connectivity has been demonstrated for Parkinson's disease. Thus, examination of the extent and types of tau and alpha-synuclein in peripheral tissues and their relation to brain neurodegenerative diseases is of relevance since it may provide insights into patterns of protein aggregation and neurodegeneration. Moreover, peripheral nervous tissues are easily accessible in-vivo and can play a relevant role in the early diagnosis of these conditions. Up-to-date investigations of tau species in peripheral tissues are scant and have mainly been restricted to rodents, whereas, more evidence is available on alpha synuclein in peripheral tissues. Here we aim to review the literature on the functional role of tau and alpha synuclein in physiological conditions and disease at the axonal level, their distribution in peripheral tissues, and discuss possible commonalities/diversities as well as their interaction in proteinopathies.

Topics: alpha-Synuclein; Animals; Axons; Humans; Mitochondria; Neurodegenerative Diseases; Synapses; tau Proteins

Mosaicism, the presence of genomic differences between cells due to post-zygotic somatic mutations, is widespread in the human body, including within the brain. A role for this in neurodegenerative diseases has long been hypothesised, and technical developments are now allowing the question to be addressed in detail. The rapidly accumulating evidence is discussed in this review, with a focus on recent developments. Somatic mutations of numerous types may occur, including single nucleotide variants (SNVs), copy number variants (CNVs), and retrotransposon insertions. They could act as initiators or risk factors, especially if they arise in development, although they could also result from the disease process, potentially contributing to progression. In common sporadic neurodegenerative disorders, relevant mutations have been reported in synucleinopathies, comprising somatic gains of SNCA in Parkinson's disease and multiple system atrophy, and in Alzheimer's disease, where a novel recombination mechanism leading to somatic variants of APP, as well as an excess of somatic SNVs affecting tau phosphorylation, have been reported. In Mendelian repeat expansion disorders, mosaicism due to somatic instability, first detected 25 years ago, has come to the forefront. Brain somatic SNVs occur in DNA repair disorders, and there is evidence for a role of several ALS genes in DNA repair. While numerous challenges, and need for further validation, remain, this new, or perhaps rediscovered, area of research has the potential to transform our understanding of neurodegeneration.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Amyotrophic Lateral Sclerosis; DNA Copy Number Variations; DNA Repair-Deficiency Disorders; DNA Repeat Expansion; Humans; Huntington Disease; Mosaicism; Multiple System Atrophy; Mutagenesis, Insertional; Mutation; Neurodegenerative Diseases; Parkinson Disease; Phosphorylation; Polymorphism, Single Nucleotide; Retroelements; Synucleinopathies; tau Proteins

A set of common-acting iron-responsive 5'untranslated region (5'UTR) motifs can fold into RNA stem loops that appear significant to the biology of cognitive declines of Parkinson's disease dementia (PDD), Lewy body dementia (LDD), and Alzheimer's disease (AD). Neurodegenerative diseases exhibit perturbations of iron homeostasis in defined brain subregions over characteristic time intervals of progression. While misfolding of Aβ from the amyloid-precursor-protein (APP), alpha-synuclein, prion protein (PrP) each cause neuropathic protein inclusions in the brain subregions, iron-responsive-like element (IRE-like) RNA stem-loops reside in their transcripts. APP and αsyn have a role in iron transport while gene duplications elevate the expression of their products to cause rare familial cases of AD and PDD. Of note, IRE-like sequences are responsive to excesses of brain iron in a potential feedback loop to accelerate neuronal ferroptosis and cognitive declines as well as amyloidosis. This pathogenic feedback is consistent with the translational control of the iron storage protein ferritin. We discuss how the IRE-like RNA motifs in the 5'UTRs of APP, alpha-synuclein and PrP mRNAs represent uniquely folded drug targets for therapies to prevent perturbed iron homeostasis that accelerates AD, PD, PD dementia (PDD) and Lewy body dementia, thus preventing cognitive deficits. Inhibition of alpha-synuclein translation is an option to block manganese toxicity associated with early childhood cognitive problems and manganism while Pb toxicity is epigenetically associated with attention deficit and later-stage AD. Pathologies of heavy metal toxicity centered on an embargo of iron export may be treated with activators of APP and ferritin and inhibitors of alpha-synuclein translation.

Topics: 5' Untranslated Regions; alpha-Synuclein; Amyloid beta-Peptides; Animals; Ferritins; Ferroptosis; Heavy Metal Poisoning; Humans; Iron-Regulatory Proteins; Neurocognitive Disorders; Neurodegenerative Diseases; Neuroprotective Agents; Protein Biosynthesis

Neurodegenerative diseases are characterized by the accumulation of disease-related misfolded proteins. It is now widely understood that the characteristic self-amplifying (i.e., seeding) capacity once only attributed to the prions of transmissible spongiform encephalopathy diseases is a feature of other misfolded proteins of neurodegenerative diseases, including tau, Aβ, and αSynuclein (αSyn). Ultrasensitive diagnostic assays, known as real-time quaking-induced conversion (RT-QuIC) assays, exploit these seeding capabilities in order to exponentially amplify protein seeds from various biospecimens. To date, RT-QuIC assays have been developed for the detection of protein seeds related to known prion diseases of mammals, the αSyn aggregates of Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, and the tau aggregates of Alzheimer's disease, chronic traumatic encephalopathy, and other tauopathies including progressive supranuclear palsy. Application of these assays to premortem human biospecimens shows promise for diagnosis of neurodegenerative disease and is an area of active investigation. RT-QuIC assays are also powerful experimental tools that can be used to dissect seeding networks within and between tissues and to evaluate how protein seed distribution and quantity correlate to disease-related outcomes in a host. As well, RT-QuIC application may help characterize molecular pathways influencing protein seed accumulation, transmission, and clearance. In this review we discuss the application of RT-QuIC assays as diagnostic, experimental, and structural tools for detection and discrimination of PrP prions, tau, and αSyn protein seeds.

Topics: alpha-Synuclein; Animals; Biomarkers; Brain; Computer Systems; High-Throughput Screening Assays; Humans; Models, Neurological; Nerve Tissue Proteins; Neurodegenerative Diseases; Prions; Protein Aggregates; Protein Folding; Proteostasis Deficiencies; tau Proteins

Alzheimer's disease (AD), Parkinson's disease (PD), and depression are growing burdens for society globally, partly due to a lack of effective treatments. Mangosteen (

Topics: alpha-Synuclein; Alzheimer Disease; Amines; Amyloid beta-Peptides; Animals; Depression; Garcinia mangostana; Humans; Neurodegenerative Diseases; Parkinson Disease; Plant Extracts; Xanthones

Neurodegenerative disorders are invariably associated with intra- or extra-cellular deposition of aggregates composed of misfolded insoluble proteins. These deposits composed of tau, amyloid-β or α-synuclein spread from cell to cell, in a prion-like manner. Emerging evidence suggests that the circulating soluble species of these misfolded proteins (usually referred as oligomers) could play a major role in pathology, while insoluble aggregates would represent their protective less toxic counterparts. Convincing data support the hypothesis that the cellular prion protein, PrP

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Neurodegenerative Diseases; Prion Proteins; Protein Aggregates; Signal Transduction

Recent studies in animal models demonstrate that certain misfolded proteins associated with neurodegenerative diseases can support templated misfolding of cognate native proteins, to propagate across neural systems, and to therefore have some of the properties of classical prion diseases like Creutzfeldt-Jakob disease. The National Institute of Aging convened a meeting to discuss the implications of these observations for research priorities. A summary of the discussion is presented here, with a focus on limitations of current knowledge, highlighting areas that appear to require further investigation in order to guide scientific practice while minimizing potential exposure or risk in the laboratory setting. The committee concluded that, based on all currently available data, although neurodegenerative disease-associated aggregates of several different non-prion proteins can be propagated from humans to experimental animals, there is currently insufficient evidence to suggest more than a negligible risk, if any, of a direct infectious etiology for the human neurodegenerative disorders defined in part by these proteins. Given the importance of this question, the potential for noninvasive human transmission of proteopathic disorders is deserving of further investigation.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Neurodegenerative Diseases; Proteostasis Deficiencies; tau Proteins

This review presents the main properties of hydroxycinnamic acid (HCA) derivatives and their potential application as agents for the prevention and treatment of neurodegenerative diseases. It is partially focused on the successful use of these compounds as inhibitors of amyloidogenic transformation of proteins. Firstly, the prerequisites for the emergence of interest in HCA derivatives, including natural compounds, are described. A separate section is devoted to synthesis and properties of HCA derivatives. Then, the results of molecular modeling of HCA derivatives with prion protein as well as with α-synuclein fibrils are summarized, followed by detailed analysis of the experiments on the effect of natural and synthetic HCA derivatives, as well as structurally similar phenylacetic and benzoic acid derivatives, on the pathological transformation of prion protein and α-synuclein. The ability of HCA derivatives to prevent amyloid transformation of some amyloidogenic proteins, and their presence not only in food products but also as natural metabolites in human blood and tissues, makes them promising for the prevention and treatment of neurodegenerative diseases of amyloid nature.

Topics: alpha-Synuclein; Amyloidogenic Proteins; Animals; Coumaric Acids; Humans; Neurodegenerative Diseases; Protein Aggregation, Pathological

Due to the progressive aging of the society, the prevalence and socioeconomic burden of neurodegenerative diseases are predicted to rise. The most common neurodegenerative disorders nowadays, such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis, can be classified as proteinopathies. They can be either synucleinopathies, amyloidopathies, tauopathies, or TDP-43-related proteinopathies; thus, nanoparticles with a potential ability to inhibit pathological protein aggregation and/or degrade already existing aggregates can be a promising approach in the treatment of neurodegenerative diseases. As it turns out, nanoparticles can be a double-edged sword; they can either promote or inhibit protein aggregation, depending on coating, shape, size, surface charge, and concentration. In this review, we aim to emphasize the need of a breakthrough in the treatment of neurodegenerative disorders and draw attention to nanomaterials, as they can also serve as a diagnostic tool for protein aggregates or can be used in a high-throughput screening for novel antiaggregative compounds.

Topics: alpha-Synuclein; Amyloidogenic Proteins; Antioxidants; Dendrimers; Humans; Nanoparticles; Neurodegenerative Diseases; Protein Aggregates; Quantum Dots; Reactive Oxygen Species

Neurodegenerative disorders are associated with intra- or extra-cellular deposition of aggregates of misfolded insoluble proteins. These deposits composed of tau, amyloid-β or α-synuclein spread from cell to cell, in a prion-like manner. Novel evidence suggests that the circulating soluble oligomeric species of these misfolded proteins could play a major role in pathology, while insoluble aggregates would represent their protective less toxic counterparts. Recent convincing data support the proposition that the cellular prion protein, PrP

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Prion Proteins; Protein Aggregation, Pathological; Signal Transduction; tau Proteins

α-synuclein and Tau are proteins prone to pathological misfolding and aggregation that are normally found in the presynaptic and axonal compartments of neurons. Misfolding initiates a homo-oligomerization and aggregation cascade culminating in cerebral accumulation of aggregated α-synuclein and Tau in insoluble protein inclusions in multiple neurodegenerative diseases. Traditionally, α-synuclein-containing Lewy bodies have been associated with Parkinson's disease and Tau-containing neurofibrillary tangles with Alzheimer's disease and various frontotemporal dementia syndromes. However, there is significant overlap and co-occurrence of α-synuclein and Tau pathologies in a spectrum of neurodegenerative diseases. Importantly, α-synuclein and Tau can interact in cells, and their pathological conformations are capable of templating further misfolding and aggregation of each other. They also share a number of protein interactors indicating that network perturbations may contribute to chronic proteotoxic stress and neuronal dysfunction in synucleinopathies and tauopathies, some of which share similarities in both neuropathological and clinical manifestations. In this review, we focus on the protein interactions of these two pathologically important proteins and consider a network biology perspective towards neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; tau Proteins

Prions are defined as proteinaceous infectious particles that do not contain nucleic acids. Neuropathological investigations of post-mortem brains and recent studies of experimental transmission have suggested that amyloid-like abnormal protein aggregates, which are the defining feature of many neurodegenerative diseases, behave like prions and propagate throughout the brain. This prion-like propagation may be the underlying mechanism of onset and progression of neurodegenerative diseases, although the precise molecular mechanisms involved remain unclear. However, in vitro and in vivo experimental models of prion-like propagation using pathogenic protein seeds are well established and are extremely valuable for the exploration and evaluation of novel drugs and therapies for neurodegenerative diseases for which there is no effective treatment. In this chapter, we introduce the experimental models of prion-like propagation of α-synuclein, which is accumulated in Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, and we describe their applications for the development of new diagnostic and therapeutic modalities. We also introduce the concept of "α-syn strains," which may underlie the pathological and clinical diversity of α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Disease Progression; Humans; Neurodegenerative Diseases; Prions; Synucleinopathies

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

It is becoming increasing clear that multiple pathological lesions co-exist in the brains of the demented and non-demented elderly, and with putative interactions revealed at the molecular level in addition to the cumulative effects on brain damage, mounting evidence suggests manifestation of multiple protein aggregates will have implications for the clinical course of many neurodegenerative diseases associated with dementia. In this section we will discuss how the presence of multiple pathological lesions can affect the pathological and clinical phenotype of neurodegenerative disorders.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Brain; Dementia; Humans; Neurodegenerative Diseases; tau Proteins

The hippocampus has a critical role in cognition and human memory and is one of the most studied structures in the brain. Despite more than 400 years of research, little is known about the Ammon's horn region cornu ammonis 2 (CA2) subfield in comparison to other subfield regions (CA1, CA3, and CA4). Recent findings have shown that CA2 plays a bigger role than previously thought. Here, we review understanding of hippocampus and CA2 ontogenesis, together with basic and clinical findings about the potential role of this region in neurodegenerative disease. The CA2 has widespread anatomical connectivity, unique signaling molecules, and intrinsic electrophysiological properties. Experimental studies using in vivo models found that the CA2 region has a role in cognition, especially in social memory and object recognition. In models of epilepsy and hypoxia, the CA2 exhibits higher resilience to cell death and hypoxia in comparison with neighboring regions, and while hippocampal atrophy remains poorly understood in Parkinson's disease (PD) and dementia with Lewy bodies (DLB), findings from postmortem PD brain demonstrates clear accumulation of α-synuclein pathology in CA2, and the CA2-CA3 region shows relatively more atrophy compared with other hippocampal subfields. Taken together, there is a growing body of evidence suggesting that the CA2 can be an ideal hallmark with which to differentiate different neurodegenerative stages of PD. Here, we summarize these recent data and provide new perspectives/ideas for future investigations to unravel the contribution of the CA2 to neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Encephalitis; Hippocampus; Humans; Lewy Body Disease; Neurodegenerative Diseases; Parkinson Disease

Neurodegenerative dementias constitute a broad group of diseases in which abnormally folded proteins accumulate in specific brain regions and result in tissue reactions that eventually cause neuronal dysfunction and degeneration. Depending on where in the brain this happens, symptoms appear which may be used to classify the disorders on clinical grounds. However, brain changes in neurodegenerative dementias start to accumulate many years prior to symptom onset and there is a poor correlation between the clinical picture and what pathology that is the most likely to cause it. Thus, novel drug candidates having disease-modifying effects that is targeting the underlying pathology and changes the course of the disease needs to be defined using objective biomarker-based measures since the clinical symptoms are often non-specific and overlap between different disorders. Furthermore, the treatment should ideally be initiated as soon as symptoms are evident or when biomarkers confirm an underlying pathology (pre-clinical phase of the disease) to reduce irreversible damage to, for example, neurons, synapses and axons. Clinical trials in the pre-clinical phase bring a greater importance to biomarkers since by definition the clinical effects are difficult or slow to discern in a population that is not yet clinically affected. Here, we discuss neuropathological changes that may underlie neurodegenerative dementias, including how they can be detected and quantified using currently available biofluid-based biomarkers and how more of them could be identified using targeted proteomics approaches. This article is part of the special issue "Proteomics".

Topics: alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Dementia; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Proteomics; tau Proteins

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

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

Synucleins are small naturally unfolded proteins involved in neurodegenerative diseases and cancer. The family contains three members: α-, β-, and -synuclein. α-Synuclein is the most thoroughly investigated because of its close association with Parkinson's disease (PD), dementia with Lewy bodies and multiple system atrophy. Until recently, the synuclein's research was mainly focused on their intracellular forms. However, new studies highlighted the important role of extracellular synucleins. Extracellular forms of synucleins propagate between various types of cells, bind to cell surface receptors and transmit signals, regulating numerous intracellular processes. Here we give an update of the latest results about the mechanisms of action of extracellular synucleins, their binding to cell surface receptors, effect on biochemical pathways and the role in neurodegeneration and neuroinflammation.

Topics: alpha-Synuclein; Animals; Extracellular Space; Humans; Matrix Metalloproteinases; Neurodegenerative Diseases; Neurons; Protein Folding; Protein Processing, Post-Translational; Receptors, Cell Surface

Changes in prolyl oligopeptidase (PREP) expression levels, protein distribution, and activity correlate with aging and are reported in many neurodegenerative conditions. Together with decreased neuropeptide levels observed in aging and neurodegeneration, and PREP's ability to cleave only small peptides, PREP was identified as a druggable target. Known PREP non-enzymatic functions were disregarded or attributed to PREP enzymatic activity, and several potent small molecule PREP inhibitors were developed during early stages of PREP research. These showed a lot of potential but with variable results in experimental memory models, however, the initial excitement was short-lived and all of the clinical trials were discontinued in either Phase I or II clinical trials for unknown reasons. Recently, PREP's ability to form protein-protein interactions, alter cell proliferation and autophagy has gained more attention than earlier recognized catalytical activity. Of new findings, particularly the aggregation of alpha-synuclein (aSyn) that is seen in the presence of PREP is especially interesting because PREP inhibitors are capable of altering aSyn-PREP interaction in a manner that reduces the aSyn dimerization process. Therefore, it is possible that PREP inhibitors that are altering interactions could have different characteristics than those aimed for strong inhibition of catalytic activity. Moreover, PREP co-localization with aSyn, tau, and amyloid-beta hints to PREP's possible role not only in the synucleinopathies but in other neurodegenerative diseases as well. This commentary will focus on less well-acknowledged non-enzymatic functions of PREP that may provide a better approach for the development of PREP inhibitors for the treatment of neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Autophagy; Enzyme Inhibitors; Humans; Neurodegenerative Diseases; Prolyl Oligopeptidases; Serine Endopeptidases

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

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

α-Synuclein is a soluble protein that is present in abundance in the brain, though its normal function in the healthy brain is poorly defined. Intraneuronal inclusions of α-synuclein, commonly referred to as Lewy pathology, are pathological hallmarks of a spectrum of neurodegenerative disorders referred to as α-synucleinopathies. Though α-synuclein is expressed predominantly in neurons, α-synuclein aggregates in astrocytes are a common feature in these neurodegenerative diseases. How and why α-synuclein ends up in the astrocytes and the consequences of this dysfunctional proteostasis in immune cells is a major area of research that can have far-reaching implications for future immunobiotherapies in α-synucleinopathies. Accumulation of aggregated α-synuclein can disrupt astrocyte function in general and, more importantly, can contribute to neurodegeneration in α-synucleinopathies through various pathways. Here, we summarize our current knowledge on how astrocytic α-synucleinopathy affects CNS function in health and disease and propose a model of neuroglial connectome altered by α-synuclein proteostasis that might be amenable to immune-based therapies.

Topics: alpha-Synuclein; Animals; Astrocytes; Homeostasis; Humans; Lewy Body Disease; Neurodegenerative Diseases; Neurons

Intrinsically disordered proteins (IDPs) do not have rigid 3D structures, showing changes in their folding depending on the environment or ligands. Intrinsically disordered proteins are widely spread in eukaryotic genomes, and these proteins participate in many cell regulatory metabolism processes. Some IDPs, when aberrantly folded, can be the cause of some diseases such as Alzheimer's, Parkinson's, and prionic, among others. In these diseases, there are modifications in parts of the protein or in its entirety. A common conformational variation of these IDPs is misfolding and aggregation, forming, for instance, neurotoxic amyloid plaques. In this review, we discuss some IDPs that are involved in neurodegenerative diseases (such as beta amyloid, alpha synuclein, tau, and the "IDP-like" PrP), cancer (p53, c-Myc), and diabetes (amylin), focusing on the structural changes of these IDPs that are linked to such pathologies. We also present the IDP modulation mechanisms that can be explored in new strategies for drug design. Lastly, we show some candidate drugs that can be used in the future for the treatment of diseases caused by misfolded IDPs, considering that cancer therapy has more advanced research in comparison to other diseases, while also discussing recent and future developments in this area of research. Therefore, we aim to provide support to the study of IDPs and their modulation mechanisms as promising approaches to combat such severe diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Diabetes Mellitus; Gene Expression Regulation; Humans; Intrinsically Disordered Proteins; Islet Amyloid Polypeptide; Neoplasms; Neurodegenerative Diseases; Protein Folding; Proto-Oncogene Proteins c-myc; tau Proteins

Lewy body diseases share clinical, pathological, genetic and biochemical signatures, and are regarded as a highly heterogeneous group of neurodegenerative disorders. Inclusive of Parkinson's disease (PD), Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), controversy still exists as to whether they should be considered as separate disease entities or as part of the same disease continuum. Here we discuss emerging knowledge relating to both clinical, and neuropathological differences and consider current biomarker strategies as we try to improve our diagnostic capabilities and design of disease modifying therapeutics for this group of debilitating neurodegenerative disorders. This article is part of the Special Issue "Synuclein".

Topics: alpha-Synuclein; Apolipoprotein E4; Biomarkers; Brain; Dementia; Diagnosis, Differential; Disease Progression; Forecasting; Glucosylceramidase; Humans; Lewy Bodies; Lewy Body Disease; Mental Status and Dementia Tests; Neurodegenerative Diseases; Parkinson Disease; Symptom Assessment; Synucleinopathies

Mutations on the GBA gene, encoding for the lysosomal enzyme β-glucocerebrosidase (GCase), have been identified as the most common genetic risk factor involved in the development of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), indicating a direct contribution of this enzyme to the pathogenesis of synucleinopathies. Decreased GCase activity has been observed repeatedly in brain tissues and biological fluids of both GBA mutation carrier and non-carrier PD and DLB patients, suggesting that lower GCase activity constitutes a typical feature of these disorders. Additional genetic, pathological and biochemical data on other lysosomal enzymes (e.g., Acid sphingomyelinase, Cathepsin D, α-galactosidase A and β-hexosaminidase) have further strengthened the evidence of a link between lysosomal dysfunction and synucleinopathies. A few studies have been performed for assessing the potential value of lysosomal enzyme activities in cerebrospinal fluid (CSF) as biomarkers for synucleinopathies. The reduction of GCase activity in the CSF of PD and DLB patients was validated in several of them, whereas the behaviour of other lysosomal enzyme activities was not consistently reliable among the studies. More in-depth investigations on larger cohorts, following stringent standard operating procedures should be committed to really understand the diagnostic utility of lysosomal enzymes as biomarkers for synucleinopathies. In this review, we reported the evidences of the association between the defective function of lysosomal proteins and the pathogenesis of synucleinopathies, and examined the role of lysosomal enzyme activities in CSF as reliable biomarkers for the diagnosis of PD and related neurodegenerative disorders.

Topics: alpha-Synuclein; Biomarkers; Brain; Humans; Lysosomes; Neurodegenerative Diseases; Protein Aggregates

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

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

Neuroinflammation and neurodegeneration often result from the aberrant deposition of aggregated host proteins, including amyloid-β, α-synuclein, and prions, that can activate inflammasomes. Inflammasomes function as intracellular sensors of both microbial pathogens and foreign as well as host-derived danger signals. Upon activation, they induce an innate immune response by secreting the inflammatory cytokines interleukin (IL)-1β and IL-18, and additionally by inducing pyroptosis, a lytic cell death mode that releases additional inflammatory mediators. Microglia are the prominent innate immune cells in the brain for inflammasome activation. However, additional CNS-resident cell types including astrocytes and neurons, as well as infiltrating myeloid cells from the periphery, express and activate inflammasomes. In this review, we will discuss current understanding of the role of inflammasomes in common degenerative diseases of the brain and highlight inflammasome-targeted strategies that may potentially treat these diseases.

Topics: alpha-Synuclein; Animals; Brain; Humans; Immunity, Innate; Inflammasomes; Interleukin-18; Interleukin-1beta; Microglia; Neurodegenerative Diseases

α-Synuclein (α-syn) represents the main component of the amyloid aggregates present in Parkinson's disease and other neurodegenerative disorders, collectively named synucleinopathies. Although α-syn is considered a natively unfolded protein, it shows great structural flexibility which allows the protein to adopt highly rich beta-sheet structures like protofibrils, oligomers and fibrils. In addition, this protein can adopt alpha-helix rich structures when interacts with fatty acids or acidic phospholipid vesicle membranes. When analyzing the toxicity of α-syn, protein oligomers are thought to be the main neurotoxic species by mechanisms that involve modification of intracellular calcium levels, mitochondrial and lysosomal function. Extracellular fibrillar α-syn promotes intracellular protein aggregation and shows many toxic effects as well. Nitro-fatty acids (nitroalkenes) represent novel pleiotropic anti-inflammatory signaling mediators that could interact with α-syn to exert unraveling actions. Herein, we demonstrated that nitro-oleic acid (NO

Topics: alpha-Synuclein; Amyloid; Humans; Neurodegenerative Diseases; Oleic Acid; Parkinson Disease; Phospholipids

After the first research declaring the generation of human induced pluripotent stem cells (hiPSCs) in 2007, several attempts have been made to model neurodegenerative disease in vitro during the past decade. Parkinson's disease (PD) is the second most common neurodegenerative disorder, which is mainly characterized by motor dysfunction. The formation of unique and filamentous inclusion bodies called Lewy bodies (LBs) is the hallmark of both PD and dementia with LBs. The key pathology in PD is generally considered to be the alpha-synuclein (α-syn) accumulation, although it is still controversial whether this protein aggregation is a cause or consequence of neurodegeneration. In the present work, the recently published researches which recapitulated the α-syn aggregation phenomena in sporadic and familial PD hiPSC models were reviewed. Furthermore, the advantages and potentials of using patient-derived PD hiPSC with focus on α-syn aggregation have been discussed. [BMB Reports 2019; 52(6): 349-359].

Topics: alpha-Synuclein; Humans; Induced Pluripotent Stem Cells; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregation, Pathological

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

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

Exosomes are extracellular membranous vesicles with a diameter of 30-100 nm derived from a variety of eukaryocytes. The cargo of exosomes includes proteins, lipids, nucleic acids, and substances of the cells from which they originate. They can transfer functional cargo to neighboring and distal cells, therefore contributing to intercellular communication in both physiological and pathological processes. In recent years, it was shown that exosomes in several neurodegenerative diseases are closely related to the transmission of disease-related misfolded proteins (such as α-synuclein, tau, amyloid β-protein, etc). These proteins are transported by exosomes, thus promoting the propagation to unaffected cells or areas and accelerating the progression of neurodegenerative diseases. This review focuses on the origin and composition, biological synthesis, secretion, function of exosomes, as well as their roles in the pathogenesis and progression of neurodegenerative diseases. In addition, we also discuss that exosomes can serve as biomarkers and drug delivery vehicles, and play a role in the diagnosis and treatment of neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Cell Communication; Exosomes; Humans; Neurodegenerative Diseases; tau Proteins

α-Synuclein (αS) is the major component of the filamentous inclusions that constitute the defining characteristic of neurodegenerative synucleinopathies, including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. αS is deposited in a hyperphosphorylated and ubiquitinated form with a β-sheet-rich fibrillar structure in diseased brains. In 2008, some researchers reported that embryonic neurons transplanted into Parkinson's disease brains had Lewy body-like pathologies, suggesting that pathological αS propagates from diseased neurons to young neurons. Subsequently, a growing body of evidence supported the cell-to-cell spread of αS pathologies. Recent studies have revealed that intracerebral injection of insoluble αS into wild-type mice can induce prion-like propagation of phosphorylated αS pathology even 1 month after injection, while injection into αS-knockout mice failed to induce any pathology. We also showed that intracerebral injection of insoluble αS into adult common marmoset brains results in the spreading of abundant αS pathology. These in vivo experiments clearly indicate that insoluble αS has prion-like properties and that it propagates through neural networks. The underlying mechanisms of αS propagation are still poorly understood, but αS propagation model animals could be helpful in elucidating the pathogenetic mechanisms and developing drugs for synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Callithrix; Humans; Lewy Body Disease; Mice; Neurodegenerative Diseases; Parkinson Disease; Phosphorylation; Prions; Protein Aggregation, Pathological

Misfolding and aggregation of alpha-synuclein (α-synuclein) with concomitant cytotoxicity is a hallmark of Lewy body related disorders such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Although it plays a pivotal role in pathogenesis and disease progression, the function of α-synuclein and the molecular mechanisms underlying α-synuclein-induced neurotoxicity in these diseases are still elusive. Many in vitro and in vivo experimental models mimicking α-synuclein pathology such as oligomerization, toxicity and more recently neuronal propagation have been generated over the years. In particular, cellular models have been crucial for our comprehension of the pathogenic process of the disease and are beneficial for screening of molecules capable of modulating α-synuclein toxicity. Here, we review α-synuclein based cell culture models that reproduce some features of the neuronal populations affected in patients, from basic unicellular organisms to mammalian cell lines and primary neurons, to the cutting edge models of patient-specific cell lines. These reprogrammed cells known as induced pluripotent stem cells (iPSCs) have garnered attention because they closely reproduce the characteristics of neurons found in patients and provide a valuable tool for mechanistic studies. We also discuss how different cell models may constitute powerful tools for high-throughput screening of molecules capable of modulating α-synuclein toxicity and prevention of its propagation. This article is part of the Special Issue "Synuclein".

Topics: alpha-Synuclein; Cell Culture Techniques; Cells, Cultured; Cellular Reprogramming; Dopamine; Drug Evaluation, Preclinical; HEK293 Cells; Humans; In Vitro Techniques; Induced Pluripotent Stem Cells; Lewy Bodies; Models, Neurological; Neurodegenerative Diseases; Neurons; Protein Aggregation, Pathological; Protein Folding; Recombinant Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Synucleinopathies

This perspective article outlines mechanisms of mitochondrial import and protein degradation and how these have been linked to alpha-synuclein and Amyloid beta (Aβ) homeostasis. Our aim is to underpin and stimulate the debate on the recent conception of mitochondria as protein degrading organelles, which suggests that mitochondria are more directly involved in neurodegenerative diseases than previously assumed.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Mitochondria; Neurodegenerative Diseases

α-Synuclein (αS) and tau have a lot in common. Dyshomeostasis and aggregation of both proteins are central in the pathogenesis of neurodegenerative diseases: Parkinson's disease, dementia with Lewy bodies, multi-system atrophy and other 'synucleinopathies' in the case of αS; Alzheimer's disease, frontotemporal dementia, progressive supranuclear palsy and other 'tauopathies' in the case of tau. The aggregated states of αS and tau are found to be (hyper)phosphorylated, but the relevance of the phosphorylation in health or disease is not well understood. Both tau and αS are typically characterized as 'intrinsically disordered' proteins, while both engage in transient interactions with cellular components, thereby undergoing structural changes and context-specific folding. αS transiently binds to (synaptic) vesicles forming a membrane-induced amphipathic helix; tau transiently interacts with microtubules forming an 'extended structure'. The regulation and exact nature of the interactions are not fully understood. Here we review recent and previous insights into the dynamic, transient nature of αS and tau with regard to the mode of interaction with their targets, the dwell-time while bound, and the cis and trans factors underlying the frequent switching between bound and unbound states. These aspects are intimately linked to hypotheses on how subtle changes in the transient behaviors may trigger the earliest steps in the pathogenesis of the respective brain diseases. Based on a deeper understanding of transient αS and tau conformations in the cellular context, new therapeutic strategies may emerge, and it may become clearer why existing approaches have failed or how they could be optimized.

Topics: alpha-Synuclein; Animals; Brain; Humans; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Folding; tau Proteins

Intra-neuronal protein aggregates made of fibrillar alpha-synuclein (α-syn) are the hallmark of Parkinson's disease (PD). With time, these aggregates spread through the brain following axonal projections. Understanding the mechanism of this spread is central to the study of the progressive nature of PD. Here we review data relevant to the uptake, transport and release of α-syn fibrils. We summarize several cell surface receptors that regulate the uptake of α-syn fibrils by neurons. The aggregates are then transported along axons, both in the anterograde and retrograde direction. The kinetics of transport suggests that they are part of the slow component b of axonal transport. Recent findings indicate that aggregated α-syn is secreted by neurons by non-canonical pathways that may implicate various molecular chaperones including USP19 and the DnaJ/Hsc70 complex. Additionally, α-syn fibrils may also be released and transmitted from neuron-to-neuron via exosomes and tunneling nanotubes. Understanding these different mechanisms and molecular players underlying α-syn spread is crucial for the development of therapies that could halt the progression of α-syn-related degenerative diseases.

Topics: alpha-Synuclein; Animals; Axonal Transport; Humans; Neurodegenerative Diseases; Neurons

The deposition of misfolded β-sheet enriched amyloid protein is a shared feature of many neurodegenerative diseases. Recent studies demonstrated the existence of conformationally diverse strains as a common property for multiple amyloidogenic proteins including α-Synuclein (α-Syn). α-Syn is misfolded and aggregated in a group of neurodegenerative diseases collectively known as α-Synucleinopathies, which include Parkinson's disease (PD), dementia with Lewy body, multiple system atrophy and also a subset of Alzheimer's disease patients with concomitant PD-like Lewy bodies and neurites. While sharing the same pathological protein, different α-Synucleinopathies demonstrate distinct clinical and pathological phenotypes, which could result from the existence of diverse pathological α-Syn strains in patients. In this review, we summarized the characteristics of different α-Synucleinopathies and α-Syn strains generated with recombinant α-Syn monomers. We also make predictions of α-Syn strains that could potentially exist in patients based on the knowledge from other amyloid proteins and the clinical and pathological features of different α-Synucleinopathies.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Conformation

Disruptions in the regulation of mitochondrial dynamics and the occurrence of proteins misfolding lead to neuronal death, resulting in Age-related Dementia and Neurodegenerative diseases as well as Frailty. Functional, neurophysiologic and biochemical alterations within the mitochondrial populations can reveal deficits in brain energy metabolism resulting in Mild Cognitive Impairment, abnormal neural development, autonomic dysfunction and other mitochondrial disorders. Additionally, in cases of Alzheimer's disease or Parkinson's disease, a significant number of proteins seem to form unordered and problematic structures, leading through unknown mechanisms to pathological conditions. While the proteins structure prediction problem is still an open challenge regarding its complexity, several features associated with the correlations of misfolding proteins and Neurodegeneration are discussed in the present study and a computational analysis for the proteins Amyloid Beta, Tau, α-Synuclein, Parkin, Pink1, MFN1, MFN1, OPA1, and DNM1L is also presented.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Cell Death; Humans; Mitochondria; Mitochondrial Dynamics; Neurodegenerative Diseases; Neurons; Protein Conformation; Protein Folding; Reactive Oxygen Species; Ubiquitin-Protein Ligases

Intracellular inclusions composed of abnormal protein aggregates are one of the neuropathological features of neurodegenerative diseases, and the formation of intracellular aggregates is believed to be associated with neurodegeneration leading to the onset of these diseases. In typical or pure cases, characteristic pathologies with one particular protein, such as tau, alpha-synuclein or trans-activation response DNA protein 43 (TDP-43), can be observed in brains of patients. On the other hand, multiple protein pathologies co-exist in many cases, raising the possibility that they may influence each other reciprocally in the pathogenesis and progression of the diseases. However, the molecular mechanisms through which these proteins interact with each other and through which they are co-deposited in brains of patients remain poorly understood. In this review, we focus on the mechanisms of deposition of multiple pathological proteins, such as tau, alpha-synuclein and/or TDP-43, and on co-deposition models of these proteins in vitro and in vivo intended to recapitulate the multiple pathologies found in diseased brains.

Topics: alpha-Synuclein; Brain; DNA-Binding Proteins; Humans; Inclusion Bodies; Neurodegenerative Diseases; tau Proteins

The formation of protein aggregates and inclusions in the brain and spinal cord is a common neuropathological feature of a number of neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and many others. These are commonly referred as neurodegenerative proteinopathies or protein-misfolding diseases. The main characteristic of protein aggregates in these disorders is the fact that they are enriched in amyloid fibrils. Since protein aggregation is considered to play a central role for the onset of neurodegenerative proteinopathies, research is ongoing to develop strategies aimed at preventing or removing protein aggregation in the brain of affected patients. Numerous studies have shown that small molecule-based approaches may be potentially the most promising for halting protein aggregation in neurodegenerative diseases. Indeed, several of these compounds have been found to interact with intrinsically disordered proteins and promote their clearing in experimental models. This notwithstanding, at present small molecule inhibitors still awaits achievements for clinical translation. Hopefully, if we determine whether the formation of insoluble inclusions is effectively neurotoxic and find a valid biomarker to assess their protein aggregation-inhibitory activity in the human central nervous system, the use of small molecule inhibitors will be considered as a cure for neurodegenerative protein-misfolding diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Neurodegenerative Diseases; Prion Proteins; Protein Aggregation, Pathological; Superoxide Dismutase-1

Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA) are neurodegenerative disorders which have been pathologically classified as synucleinopathies, since they are associated with pathognomonic deposits of misfolded alpha-synuclein in cells of the nervous system. Recently PD, DLB, and MSA were also suggested to be prion-like disorders. Much controversy exists regarding this analogy between synucleinopathies and prion diseases. Here, we discuss what characterizes prion diseases and in which way synucleinopathies may be considered prion-like or -unlike. We critically review recent clinical and in vivo evidence from transmission studies to animals in support of or questioning the prion hypothesis of human synucleinopathies. We conclude that, although PD, DLB, and MSA fulfill many criteria of prion-likeness, they also still fail some of these criteria.

Topics: alpha-Synuclein; Humans; Models, Biological; Neurodegenerative Diseases; Prions

So-called idiopathic rapid eye movement (REM) sleep behaviour disorder (RBD), formerly seen as a rare parasomnia, is now recognized as the prodromal stage of an α-synucleinopathy. Given the very high risk that patients with idiopathic RBD have of developing α-synucleinopathies, such as Parkinson disease (PD), PD dementia, dementia with Lewy bodies or multiple system atrophy, and the outstandingly high specificity and very long interval between the onset of idiopathic RBD and the clinical manifestations of α-synucleinopathies, the prodromal phase of this disorder represents a unique opportunity for potentially disease-modifying intervention. This Review provides an update on classic and novel biomarkers of α-synuclein-related neurodegeneration in patients with idiopathic RBD, focusing on advances in imaging and neurophysiological, cognitive, autonomic, tissue-specific and other biomarkers. We discuss the strengths, potential weaknesses and suitability of these biomarkers for identifying RBD and neurodegeneration, with an emphasis on predicting progression to overt α-synucleinopathy. The role of video polysomnography in providing quantifiable and potentially treatment-responsive biomarkers of neurodegeneration is highlighted. In light of all these advances, and the now understood role of idiopathic RBD as an early manifestation of α-synuclein disease, we call for idiopathic RBD to be reconceptualized as isolated RBD.

Topics: alpha-Synuclein; Biomarkers; Humans; Neurodegenerative Diseases; REM Sleep Behavior Disorder

Over the course of most common neurodegenerative diseases the amygdala accumulates pathologically misfolded proteins. Misfolding of 1 protein in aged brains often is accompanied by the misfolding of other proteins, suggesting synergistic mechanisms. The multiplicity of pathogenic processes in human amygdalae has potentially important implications for the pathogenesis of Alzheimer disease, Lewy body diseases, chronic traumatic encephalopathy, primary age-related tauopathy, and hippocampal sclerosis, and for the biomarkers used to diagnose those diseases. Converging data indicate that the amygdala may represent a preferential locus for a pivotal transition from a relatively benign clinical condition to a more aggressive disease wherein multiple protein species are misfolded. Thus, understanding of amygdalar pathobiology may yield insights relevant to diagnoses and therapies; it is, however, a complex and imperfectly defined brain region. Here, we review aspects of amygdalar anatomy, connectivity, vasculature, and pathologic involvement in neurodegenerative diseases with supporting data from the University of Kentucky Alzheimer's Disease Center autopsy cohort. Immunohistochemical staining of amygdalae for Aβ, Tau, α-synuclein, and TDP-43 highlight the often-coexisting pathologies. We suggest that the amygdala may represent an "incubator" for misfolded proteins and that it is possible that misfolded amygdalar protein species are yet to be discovered.

Topics: alpha-Synuclein; Amygdala; Amyloid beta-Peptides; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Protein Folding; tau Proteins

Research on human brain diseases is currently often conducted on cell cultures and animals. Several questions however can only be addressed by studying human postmortem brain tissue. However, brain tissue obtained postmortem almost always displays pathology that is often related to the aging phenomenon. Thus, in order to be certain that the answers obtained are reliable, a systematic and thorough assessment of the brain tissue to be studied should be carried out. We are currently aware of several protein alterations that are found in middle-aged and aged brains that are obtained from neurologically unimpaired subjects. The most common alteration is hyperphosphorylation of τ, observed in both neurons and glial cells, in certain brain regions, followed by β-amyloid aggregation in the neuropil and vessel walls. Less common protein alterations are those noted for α-synuclein and Tar DNA-binding protein 43. It is noteworthy that these alterations, when found in excess, are diagnostic for various neurodegenerative diseases, such as Alzheimer disease, Pick disease, progressive supranuclear palsy, corticobasal degeneration, Parkinson disease, Lewy body dementia, and frontotemporal lobar degeneration. Since 1990, the neuropathology community has been aware that these protein alterations tend to progress in an orderly neuroanatomically defined manner and have thus designed a method to define a stage or a phase of the protein alteration. The neuropathology community has defined an initiation site, or neuroanatomic area that they presume the alteration originates from, and defined a presumed pattern of progression from the initiation site to other brain areas. Thus a reliable and reproducible description of each case regarding these alterations can be achieved. In addition to the above alterations, the brain tissue is also prone to various vascular alterations that should be registered as seen or not seen even if the significance of these alterations is still unclear.

Topics: Aged; Aging; alpha-Synuclein; Amyloid beta-Peptides; Brain; DNA-Binding Proteins; Humans; Middle Aged; Neurodegenerative Diseases; Neurons; tau Proteins; Tissue Banks; Ubiquitin

Protein misfolding and aggregation have been considered the common pathological hallmarks for a number of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). These abnormal proteins aggregates damage mitochondria and induce oxidative stress, resulting in neuronal cell death. Prolonged neuronal damage activates microglia and astrocytes, development of inflammation reaction and further promotes neurodegeneration. Thus, elimination of abnormal protein aggregates without eliciting any adverse effects are the main treatment strategies. To overcome this, recent studies have deployed single- chain fragment variable antibodies (scFvs) to target the pathological protein aggregates, such as amyloid-beta (Aβ) peptides, α-synuclein (α-syn) and Huntingtin (Htt). To date scFv has been effective at inhibiting abnormal protein aggregates formation in both in vitro and in vivo model system of AD, PD and HD.. Currently active research is still ongoing to improve the scFv gene delivery technology, to further enhance brain penetration, intracellular stability, solubility and efficacy of scFv intrabody.

Topics: alpha-Synuclein; Amyloidogenic Proteins; Animals; Humans; Huntingtin Protein; Neurodegenerative Diseases; Single-Chain Antibodies

The second-most common neurodegenerative disease, Parkinson's Disease (PD) has three hallmarks: dysfunctional dopamine transmission due, at least in part, to dopamine neuron degeneration; intracellular inclusions of α-synuclein aggregates; and neuroinflammation. The origin and interplay of these features remains a puzzle, as does the underlying mechanism of PD pathogenesis and progression. When viewed in the context of neuroimmunology, dopamine also plays a role in regulating peripheral immune cells. Intriguingly, plasma dopamine levels are altered in PD, suggesting collateral dysregulation of peripheral dopamine transmission. The dopamine transporter (DAT), the main regulator of dopaminergic tone in the CNS, is known to exist in lymphocytes and monocytes/macrophages, but little is known about peripheral DAT biology or how DAT regulates the dopaminergic tone, much less how peripheral DAT alters immune function. Our review is guided by the hypothesis that dysfunctional peripheral dopamine signaling might be linked to the dysfunctional immune responses in PD and thereby suggests a potential bidirectional communication between central and peripheral dopamine systems. This review seeks to foster new perspectives concerning PD pathogenesis and progression.

Topics: alpha-Synuclein; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopaminergic Neurons; Humans; Lymphocytes; Macrophages; Monocytes; Nerve Degeneration; Neurodegenerative Diseases; Parkinson Disease; Signal Transduction

Neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD) impose a pressing burden on our developed and consequently aging society. Misfolded protein aggregates are a critical aspect of several neurodegenerative diseases. Nevertheless, several questions remain unanswered regarding the role of misfolded protein aggregates and the cause of neuronal cell death. Recently, it has been postulated that neuroinflammatory processes might play a crucial role in the pathogenesis of PD. Numerous postmortem, brain imaging, epidemiological, and animal studies have documented the involvement of the innate and adaptive immunity in neurodegeneration. Whether these inflammatory processes are directly involved in the etiology of PD or represent secondary consequences of nigrostriatal pathway injury is the subject of intensive research. Immune alterations in response to extracellular

Topics: alpha-Synuclein; Animals; Apoptosis; Humans; Inflammation; Neurodegenerative Diseases; Neurogenic Inflammation; Neurons; Parkinson Disease; Proteostasis Deficiencies

α-Synuclein (α-syn) is a 140-amino acid protein, the physiological function of which has yet to be clarified. It is involved in several neurodegenerative disorders, and the interaction of the protein with brain lipids plays an important role in the pathogenesis of Parkinson's disease (PD). Polyunsaturated fatty acids (PUFA) are highly abundant in the brain where they play critical roles in neuronal membrane fluidity and permeability, serve as energy reserves and function as second messengers in cell signaling. PUFA concentration and composition in the brain are altered with age when also an increase of lipid peroxidation is observed. Considering that PD is clearly correlated with oxidative stress, PUFA abundance and composition became of great interest in neurodegeneration studies because of PUFA's high propensity to oxidize. The high levels of the PUFA docosahexaenoic acid (DHA) in brain areas containing α-syn inclusions in patients with PD further support the hypothesis of possible interactions between α-syn and DHA. Additionally, a possible functional role of α-syn in sequestering the early peroxidation products of fatty acids was recently proposed. Here, we provide an overview of the current knowledge regarding the molecular interactions between α-syn and fatty acids and the effect exerted by the protein on their oxidative state. We highlight recent findings supporting a neuroprotective role of the protein, linking α-syn, altered lipid composition in neurodegenerative disorders and PD development.

Topics: alpha-Synuclein; Animals; Fatty Acids, Unsaturated; Humans; Neurodegenerative Diseases; Parkinson Disease

Neurodegenerative proteinopathies are a group of pathologically similar, progressive disorders of the nervous system, characterised by structural alterations within and toxic misfolding of susceptible proteins. Oligomerisation of Aβ, tau, α-synuclein and TDP-43 leads to a toxin gain- or loss-of-function contributing to the phenotype observed in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and frontotemporal dementia. Misfolded proteins can adversely affect mitochondria, and post-mitotic neurones are especially sensitive to metabolic dysfunction. Misfolded proteins impair mitochondrial dynamics (morphology and trafficking), preventing functional mitochondria reaching the synapse, the primary site of ATP utilisation. Furthermore, a direct association of misfolded proteins with mitochondria may precipitate or augment dysfunctional oxidative phosphorylation and mitochondrial quality control, causing redox dyshomeostasis observed in disease. As such, a significant interest lies in understanding mechanisms of mitochondrial toxicity in neurodegenerative disorders and in dissecting these mechanisms with a view of maintaining mitochondrial homeostasis in disease. Recent advances in understanding mitochondrially controlled cell death pathways and elucidating the mitochondrial permeability pore bioarchitecture are beginning to present new avenues to target neurodegeneration. Novel mitochondrial roles of deubiquitinating enzymes are coming to light and present an opportunity for a new class of proteins to target therapeutically with the aim of promoting mitophagy and the ubiquitin-proteasome system. The brain is enormously metabolically active, placing a large emphasis on maintaining ATP supply. Therefore, identifying mechanisms to sustain mitochondrial function may represent a common intervention point across all proteinopathies.

Topics: Adenosine Triphosphate; alpha-Synuclein; Amyloid beta-Peptides; Animals; Homeostasis; Humans; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitophagy; Nerve Tissue Proteins; Neurodegenerative Diseases; Oxidative Phosphorylation; Proteasome Endopeptidase Complex; Reactive Oxygen Species; tau Proteins; Ubiquitin

Protein aggregation is a hallmark of many neurodegenerative diseases. In Parkinson's disease protein misfolding of α-synuclein involves conformational changes in the protein structure that often results in self-association and aggregation leading to accumulation of α-synuclein in neuronal cells. The underlying mechanisms by which aggregations can lead to impaired cellular functions are often not understood. Meanwhile, there is growing evidence that links mitochondrial dysfunction to Parkinson's disease. As both mitochondria and protein aggregation of α-synuclein have been shown to play a major role in Parkinson's disease, it seems likely that a converging mechanism exists that links the two pathways.

Topics: alpha-Synuclein; Animals; Humans; Mitochondria; Neurodegenerative Diseases; Parkinson Disease; Protein Conformation

While cytokines such as TNF have long been recognized as essential to normal cerebral physiology, the implications of their chronic excessive production within the brain are now also increasingly appreciated. Syndromes as diverse as malaria and lead poisoning, as well as non-infectious neurodegenerative diseases, illustrate this. These cytokines also orchestrate changes in tau, α-synuclein, amyloid-β levels and degree of insulin resistance in most neurodegenerative states. New data on the effects of salbutamol, an indirect anti-TNF agent, on α-synuclein and Parkinson's disease, APOE4 and tau add considerably to the rationale of the anti-TNF approach to understanding, and treating, these diseases. Therapeutic advances being tested, and arguably useful for a number of the neurodegenerative diseases, include a reduction of excess cerebral TNF, whether directly, with a specific anti-TNF biological agent such as etanercept via Batson's plexus, or indirectly via surgically implanting stem cells. Inhaled salbutamol also warrants investigating further across the neurodegenerative disease spectrum. It is now timely to integrate this range of new information across the neurodegenerative disease spectrum, rather than keep seeing it through the lens of individual disease states.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Apolipoproteins E; Humans; Insulin Resistance; Neurodegenerative Diseases; Phosphorylation; tau Proteins; Tumor Necrosis Factor-alpha

Cells rely on surveillance systems such as autophagy to handle protein alterations and organelle damage. Dysfunctional autophagy, an evolutionarily conserved cellular mechanism for degradation of intracellular components in lysosomes, frequently leads to neurodegeneration. The neuroprotective effect of autophagy stems from its ability to eliminate pathogenic forms of proteins such as α-synuclein or tau. However, the same pathogenic proteins often affect different types and steps of the autophagic process. Furthermore, genetic studies have shown that some proteins related to neurodegeneration, such as huntingtin, participate in autophagy as one of their physiological functions. This complex interplay between autophagy and neurodegeneration suggests that targeting autophagy as a whole might have limited applicability in neurodegenerative diseases, and that future efforts should focus instead on targeting specific types and steps of the autophagic process. This change of strategy in the modulation of autophagy might hold promise for future disease-modifying therapies for patients with neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Autophagy; Humans; Neurodegenerative Diseases; Neuroprotective Agents

Topics: alpha-Synuclein; Animals; Bridged Bicyclo Compounds; Drug Design; Humans; Neurodegenerative Diseases; Patents as Topic; Pharmacokinetics

Amyloids are highly ordered aggregates of protein fibrils exhibiting cross-β structure formed by intermolecular hydrogen bonds. Pathological amyloid deposition is associated with the development of several socially significant incurable human diseases. Of particular interest are infectious amyloids, or prions, that cause several lethal neurodegenerative diseases in humans and can be transmitted from one organism to another. Because of almost complete absence of criteria for infectious and non-infectious amyloids, there is a lack of consensus, especially, in the definition of similarities and differences between prions and non-infectious amyloids. In this review, we formulated contemporary molecular-biological criteria for identification of prions and non-infectious amyloids and focused on explaining the differences between these two types of molecules.

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Animals; Humans; Huntingtin Protein; Neurodegenerative Diseases; Prions; Protein Aggregates; tau Proteins

Synucleinopathies are a group of neurodegenerative diseases that share a common pathological lesion of intracellular protein inclusions largely composed of aggregates of alpha-synuclein protein. Accumulating evidence, including genome-wide association studies, has implicated the alpha-synuclein (SNCA) gene in the etiology of synucleinopathies and it has been suggested that SNCA expression levels are critical for the development of these diseases. This review focuses on genetic variants from the class of structural variants (SVs), including multiplication of large genomic segments and short (<50bp) genomic variants such as simple sequence repeats (SSRs), within the SNCA locus. We provide evidence that SNCA-SVs play a key role in the pathogenesis of synucleinopathies via their effects on gene expression and on regulatory mechanisms including transcription and splicing.

Topics: alpha-Synuclein; Genomic Structural Variation; Humans; Microsatellite Repeats; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregation, Pathological; Protein Conformation

Neurodegenerative diseases such as Alzheimer's disease (AD), frontotemporal lobar degeneration (FTD), Lewy body disease (LBD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) have in common that protein aggregates represent pathological hallmark lesions. Amyloid β-protein, τ-protein, α-synuclein, and TDP-43 are the most frequently aggregated proteins in these disorders. Although they are assumed to form disease-characteristic aggregates, such as amyloid plaques and neurofibrillary tangles in AD or Lewy bodies in LBD/PD, they are not restricted to these clinical presentations. They also occur in non-diseased individuals and can co-exist in the same brain without or with a clinical picture of a distinct dementing or movement disorder. In this review, we discuss the co-existence of these pathologies and potential additive effects in the human brain as well as related functional findings on cross-seeding and molecular interactions between these aggregates/proteins. We conclude that there is evidence for interactions at the molecular level as well as for additive effects on brain damage by multiple pathologies occurring in different functionally important neurons. Based upon this information, we hypothesize a cascade of events that may explain general mechanisms in the development of neurodegenerative disorders: (1) distinct lesions are a prerequisite for the development of a distinct disease (e.g., primary age-related tauopathy for AD), (2) disease-specific pathogenic events further trigger the development of a specific disease (e.g., Aβ aggregation in AD that exaggerate further Aβ and AD-related τ pathology), (3) the symptomatic disease manifests, and (4) neurodegenerative co-pathologies may be either purely coincidental or (more likely) have influence on the disease development and/or its clinical presentation.

Topics: Aging; alpha-Synuclein; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; tau Proteins

Autophagy, a catabolic process necessary for the maintenance of intracellular homeostasis, has recently been the focus of numerous human diseases and conditions, such as aging, cancer, development, immunity, longevity, and neurodegeneration. However, the continued presence of autophagy is essential for cell survival and dysfunctional autophagy is thought to speed up the progression of neurodegeneration. The actual molecular mechanism behind the progression of dysfunctional autophagy is not yet fully understood. Emerging evidence suggests that basal autophagy is necessary for the removal of misfolded, aggregated proteins and damaged cellular organelles through lysosomal mediated degradation. Physiologically, neurodegenerative disorders are related to the accumulation of amyloid β peptide and α-synuclein protein aggregation, as seen in patients with Alzheimer's disease and Parkinson's disease, respectively. Even though autophagy could impact several facets of human biology and disease, it generally functions as a clearance for toxic proteins in the brain, which contributes novel insight into the pathophysiological understanding of neurodegenerative disorders. In particular, several studies demonstrate that natural compounds or small molecule autophagy enhancer stimuli are essential in the clearance of amyloid β and α-synuclein deposits. Therefore, this review briefly deliberates on the recent implications of autophagy in neurodegenerative disorder control, and emphasizes the opportunities and potential therapeutic application of applied autophagy. [BMB Reports 2017; 50(7): 345-354].

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Autophagy; Humans; Neurodegenerative Diseases; Protein Aggregates

Several neurodegenerative disorders, such as Alzheimer's and Parkinson's disease, are characterized by prominent loss of synapses and neurons associated with the presence of abnormally structured or misfolded protein assemblies. Cell-to-cell transfer of misfolded proteins has been proposed for the intra-cerebral propagation of these diseases. When released, misfolded proteins diffuse in the 3D extracellular space before binding to the plasma membrane of neighboring cells, where they diffuse on a 2D plane. This reduction in diffusion dimension and the cell surface molecular crowding promote deleterious interactions with native membrane proteins, favoring clustering and further aggregation of misfolded protein assemblies. These processes open up new avenues for therapeutics development targeting the initial interactions of deleterious proteins with the plasma membrane or the subsequent pathological signaling.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Animals; Cell Membrane; Extracellular Space; Humans; Huntingtin Protein; Huntington Disease; Neurodegenerative Diseases; Parkinson Disease; Prions; Protein Aggregation, Pathological; Protein Folding; Protein Transport; Superoxide Dismutase-1; tau Proteins

In this chapter, we provide a review of the challenges and advances in developing successful PET imaging agents for 3 major types of aggregated amyloid proteins: amyloid-beta (Aβ), tau, and alpha-synuclein (α-syn). These 3 amyloids are involved in the pathogenesis of a variety of neurodegenerative diseases, referred to as proteinopathies or proteopathies, that include Alzheimer disease, Lewy body dementias, multiple system atrophy, and frontotemporal dementias, among others. In the Introduction section, we briefly discuss the history of amyloid in neurodegenerative diseases and describe why progress in developing effective imaging agents has been hampered by the failure of crystallography to provide definitive ligand-protein interactions for rational radioligand design efforts. Instead, the field has relied on largely serendipitous, trial-and-error methods to achieve useful and specific PET amyloid imaging tracers for Aβ, tau, and α-syn deposits. Because many of the proteopathies involve more than 1 amyloid protein, it is important to develop selective PET tracers for the different amyloids to help assess the relative contribution of each to total amyloid burden. We use Pittsburgh compound B to illustrate some of the critical steps in developing a potent and selective Aβ PET imaging agent. Other selective Aβ and tau PET imaging compounds have followed similar pathways in their developmental processes. Success for selective α-syn PET imaging agents has not been realized yet, but work is ongoing in multiple laboratories throughout the world. In the tau sections, we provide background regarding 3-repeat (3R) and 4-repeat (4R) tau proteins and how they can affect the binding of tau radioligands in different tauopathies. We review the ongoing efforts to assess the properties of tau ligands, which are useful in 3R, 4R, or combined 3R-4R tauopathies. Finally, we describe in the α-syn sections recent attempts to develop selective tracers to image α-synucleinopathies.

Topics: alpha-Synuclein; Alzheimer Disease; Humans; Neurodegenerative Diseases; Positron-Emission Tomography; Small Molecule Libraries; tau Proteins

This review considers the interrelation between different types of protein glycation, glycolysis, and the development of amyloid neurodegenerative diseases. The primary focus is on the role of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase in changing the concentration of carbonyl compounds - first and foremost, glyceraldehyde-3-phosphate and methylglyoxal. It has been suggested that various modifications of the enzyme - from the oxidation of the sulfhydryl groups of the active site to glycation with sugars - can lead to its inactivation, which causes a direct increase in glyceraldehyde-3-phosphate concentration and an indirect increase in the content of other aldehydes. This "primary inactivation" of glyceraldehyde-3-phosphate dehydrogenase promotes its glycation with aldehydes, including its own substrate, and a further irreversible decrease in its activity. Such a cycle can lead to numerous consequences - from the induction of apoptosis, which is activated by modified forms of the enzyme, to glycation of amyloidogenic proteins by glycolytic aldehydes. Of particular importance during the inhibition of glyceraldehyde-3-phosphate dehydrogenase is an increase in the content of the glycating compound methylglyoxal, which is much more active than reducing sugars (glucose, fructose, and others). In addition, methylglyoxal is formed by two pathways - in the cascade of reactions during glycation and from glycolytic aldehydes. The ability of methylglyoxal to glycate proteins makes it the main participant in this protein modification. We consider the effect of glycation on the pathological transformation of amyloidogenic proteins and peptides - β-amyloid peptide, α-synuclein, and prions. Our primary focus is on the glycation of monomeric forms of these proteins with methylglyoxal, although most works are dedicated to the analysis of the presence of "advanced glycation end products" in the already formed aggregates and fibrils of amyloid proteins. In our opinion, the modification of aggregates and fibrils is secondary in nature and does not play an important role in the development of neurodegenerative diseases. The glycation of amyloid proteins with carbonyl compounds can be one of the triggers of their transformation into toxic forms. The possible role of glycation of amyloidogenic proteins in the prevention of their modification by ubiquitin and the SUMO proteins due to a disruption of their degradation is separately considered.

Topics: Aldehydes; alpha-Synuclein; Amyloidogenic Proteins; Glycation End Products, Advanced; Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+); Glycolysis; Glycosylation; Humans; Neurodegenerative Diseases; Protein Processing, Post-Translational

A neurodegenerative disorder displaying an altered α-synuclein (αS) in the brain tissue is called α-synucleinopathy (αS-pathy) and incorporates clinical entities such as Parkinson disease (PD), PD with dementia, dementia with Lewy bodies, and multiple-system atrophy. Neuroradiologic techniques visualizing αS pathology in the brain or assays of αS in the cerebrospinal fluid or blood are probably available and will be implemented in the near future but currently the definite diagnosis of αS-pathy relies on a postmortem examination of the brain. Since the 1980s immunohistochemical technique based on the use of antibodies directed to proteins of interest has become a method of choice for neuropathologic diagnosis. Furthermore, since the 1990s it has been acknowledged that progressions of most neurodegenerative pathologies follow a certain predictable time-related neuroanatomic distribution. Currently, for Lewy body disease, two staging techniques are commonly used: McKeith and Braak staging. Thus, the neuropathologic diagnosis of a αS-pathy is based on detection of altered αS in the tissue and registration of the neuroanatomic distribution of this alteration in the brain. The clinicopathologic correlation is not absolute due to the quite frequent observation of incidental and concomitant αS pathology.

Topics: alpha-Synuclein; Animals; Brain; Humans; Lewy Bodies; Neurodegenerative Diseases

The homeostasis of iron is vital to human health, and iron dyshomeostasis can lead to various disorders. Iron homeostasis is maintained by iron regulatory proteins (IRP1 and IRP2) and the iron-responsive element (IRE) signaling pathway. IRPs can bind to RNA stem-loops containing an IRE in the untranslated region (UTR) to manipulate translation of target mRNA. However, iron can bind to IRPs, leading to the dissociation of IRPs from the IRE and altered translation of target transcripts. Recently an IRE is found in the 5'-UTR of amyloid precursor protein (APP) and α-synuclein (α-Syn) transcripts. The levels of α-Syn, APP and amyloid β-peptide (Aβ) as well as protein aggregation can be down-regulated by IRPs but are up-regulated in the presence of iron accumulation. Therefore, inhibition of the IRE-modulated expression of APP and α-Syn or chelation of iron in patient's brains has therapeutic significance to human neurodegenerative diseases. Currently, new pre-drug IRE inhibitors with therapeutic effects have been identified and are at different stages of clinical trials for human neurodegenerative diseases. Although some promising drug candidates of chemical IRE inhibitors and iron-chelating agents have been identified and are being validated in clinical trials for neurodegenerative diseases, future studies are expected to further establish the clinical efficacy and safety of IRE inhibitors and iron-chelating agents in patients with neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Gene Expression Regulation; Homeostasis; Humans; Iron; Iron-Regulatory Proteins; Neurodegenerative Diseases; Signal Transduction

Mitochondria participate in essential processes in the nervous system such as energy and intermediate metabolism, calcium homeostasis, and apoptosis. Major neurodegenerative diseases are characterized pathologically by accumulation of misfolded proteins as a result of gene mutations or abnormal protein homeostasis. Misfolded proteins associate with mitochondria, forming oligomeric and fibrillary aggregates. As mitochondrial dysfunction, particularly of the oxidative phosphorylation system (OXPHOS), occurs in neurodegeneration, it is postulated that such defects are caused by the accumulation of misfolded proteins. However, this hypothesis and the pathological role of proteinopathies in mitochondria remain elusive. In this study, we critically review the proposed mechanisms whereby exemplary misfolded proteins associate with mitochondria and their consequences on OXPHOS.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Gene Expression Regulation; Humans; Mitochondria; Mitochondrial Proteins; Neurodegenerative Diseases; Oxidative Phosphorylation; Protein Interaction Mapping; Proteostasis Deficiencies

Alzheimer's and Parkinson's diseases are the most prevalent neurodegenerative diseases that generate important health-related direct and indirect socio-economic costs. They are characterized by severe neuronal losses in several disease-specific brain regions associated with deposits of aggregated proteins. In Alzheimer's disease, β-amyloid peptide-containing plaques and intraneuronal neurofibrillary tangles composed of hyperphosphorylated microtubule-associated protein tau are the two main neuropathological lesions, while Parkinson's disease is defined by the presence of Lewy Bodies that are intraneuronal proteinaceous cytoplasmic inclusions. α-Synuclein has been identified as a major protein component of Lewy Bodies and heavily implicated in the pathogenesis of Parkinson's disease. In the past few years, evidence has emerged to explain how these aggregate-prone proteins can undergo spontaneous self-aggregation, propagate from cell to cell, and mediate neurotoxicity. Current research now indicates that oligomeric forms are probably the toxic species. This article discusses recent progress in the understanding of the pathogenesis of these diseases, with a focus on the underlying mechanisms of protein aggregation, and emphasizes the pathophysiological molecular mechanisms leading to cellular toxicity. Finally, we present the putative direct link between β-amyloid peptide and tau in causing toxicity in Alzheimer's disease as well as α-synuclein in Parkinson's disease, along with some of the most promising therapeutic strategies currently in development for those incurable neurodegenerative disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Humans; Nerve Degeneration; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregation, Pathological; Tauopathies

Clinical classifications of neurodegenerative disorders are often based on neuropathology. The term "proteinopathies" includes disorders that have in common abnormal proteins as a hallmark, e.g. amyloidoses, tauopathies, synucleopathies, ubiquitinopathies. Different proteins can also co-exist in the same disease. To further complicate the pathophysiology scenario, not only different proteins, but also cells are believed to play an active role in neurodegeneration, in particular those participating in neuroinflammatory processes in the brain, such as activated microglia and astrocytes. In clinical practice, differentiating pathophysiology from clinical symptoms to allow accurate clinical classification of these disorders during life, becomes difficult in absence of biomarkers for these pathology hallmarks. PET imaging can be a useful tool in this context. Using PET tracers targeting misfolded proteins it will be possible to identify the presence or absence of the target, to depict the cerebral distribution and to quantify the protein load in different cerebral regions, as well as to monitor changes over time. Beta-amyloid is one of the proteins involved in neurodegenerative disorders, which is currently suitable to be imaged by means of PET. Research efforts are currently ongoing in order to identify new PET tracers targeting non-amyloid PET tracers for neurodegeneration. This article will focus on the investigational PET tracers targeting tau and alpha-synuclein as misfolded proteins, and activated microglia and astrocytes as cellular targets for neuroinflammation. An overview of target characteristics, development challenges, clinical relevance and current status of human PET imaging is provided.

Topics: alpha-Synuclein; Animals; Biomarkers; Brain; Humans; Inflammation; Neurodegenerative Diseases; Positron-Emission Tomography; tau Proteins

The abnormal aggregation of a small number of known proteins underlies the most common human neurodegenerative diseases. In tauopathies and synucleinopathies, the normally soluble intracellular proteins tau and α-synuclein become insoluble and filamentous. In recent years, non-cell autonomous mechanisms of aggregate formation have come to the fore, suggesting that nucleation-dependent aggregation may occur in a localized fashion in human tauopathies and synucleinopathies, followed by seed-dependent propagation. There is a long prodromal phase between the formation of protein aggregates and the appearance of the first clinical symptoms, which manifest only after extensive propagation, opening novel therapeutic avenues.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Prion Proteins; Protein Aggregation, Pathological; tau Proteins

It is now established that numerous amyloid proteins associated with neurodegenerative diseases, including tau and α-synuclein, have essential characteristics of prions, including the ability to create transmissible cellular pathology in vivo. We have developed cellular bioassays that report on the various features of prion activity using genetic engineering and quantitative fluorescence-based detection systems. We have exploited these biosensors to measure the binding and uptake of tau seeds into cells in culture and to quantify seeding activity in brain samples. These cell models have also been used to propagate tau prion strains indefinitely in culture. In this review, we illustrate the utility of cellular biosensors to gain mechanistic insight into prion transmission and to study neurodegenerative diseases in a reductionist fashion.

Topics: alpha-Synuclein; Animals; Biosensing Techniques; Brain; Cell Culture Techniques; Humans; Neurodegenerative Diseases; Prion Diseases; Prions; tau Proteins

Abnormal deposition of α-synuclein (ASN) is a hallmark and possible central mechanism of Parkinson's disease and other synucleinopathies. Their therapy is currently hampered by the lack of early, screening-compatible diagnostic methods and efficient treatments. Areas covered: Patent applications related to synucleinopathies obtained from Patentscope and Espacenet databases are described against the background of current knowledge regarding the regulatory mechanisms of ASN behavior including alternative splicing, post-translational modifications, molecular interactions, aggregation, degradation, and changes in localization. Expert opinion: As the central pathological feature and possibly one of root causes in a number of neurodegenerative diseases, deregulation of ASN is a potentially optimal diagnostic and therapeutic target. Changes in total ASN may have diagnostic value, especially if non-invasive /peripheral tissue tests can be developed. Targeting the whole ASN pool for therapeutic purposes may be problematic, however. ASN mutations, truncation, and post-translational modifications have great potential value; therapeutic approaches selective towards aggregated or aggregation-prone ASN forms may lead to more successful and safe treatments. Numerous ASN interactions with signaling pathways, protein degradation and stress mechanisms widen its potential therapeutic significance dramatically. However, significant improvement in the basic knowledge on ASN is necessary to fully exploit these opportunities.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; Drug Design; Humans; Neurodegenerative Diseases; Parkinson Disease; Patents as Topic; Signal Transduction

Prion-like propagation of abnormal intracytoplasmic proteins, which are the defining features of major neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), has been proposed. A growing body of evidence strongly suggests that abnormal tau, α-synuclein and TDP-43 have prion-like properties, convert the corresponding normal proteins into abnormal forms, and are transmitted from cell to cell, spreading throughout the brain. This idea is extremely important not only for understanding the pathogenesis and progression of these diseases, but also for the development of molecular therapies. Since the distributions and spreading of the abnormal proteins are closely associated with disease symptoms and progression, gain-of-toxic-function of these proteins may affect the neurons and glial cells either directly or indirectly, or both. It is essential to regulate the aggregation of abnormal intracellular proteins and their cell-to-cell transmission in order to stop, or at least slow, the progression of these diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyotrophic Lateral Sclerosis; Animals; Disease Progression; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Parkinson Disease; Prions; tau Proteins

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream enactment behavior during REM sleep. It has been demonstrated that patients with idiopathic RBD are at a significantly increased risk of developing one of the α-synucleinopathies later in life, and this is called "phenoconversion". Although some physicians argue against disclosing information that could cause patients psychological stress, the patients also have a "right to know" about their own disease. Therefore, determining when and how to disclose this information, in addition to appropriate follow-up, is important. Clonazepam is the first choice of treatment for RBD associated with α-synucleinopathies. Since RBD is one of the premotor symptoms of α-synucleinopathies, and enables its early diagnosis, a combination of RBD and other examinations may contribute to the realization of a disease-modifying therapy. It is hoped that the early establishment of biomarkers could help predict the phenoconversion from RBD to α-synucleinopathies.

Topics: alpha-Synuclein; Clonazepam; Diagnosis, Differential; Humans; Neurodegenerative Diseases; REM Sleep Behavior Disorder; Stress, Psychological; Truth Disclosure

Mutations in the

Topics: alpha-Synuclein; GTP Phosphohydrolases; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Models, Genetic; Mutation; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; tau Proteins

α-Synucleinopathies (ASP) comprise adult-onset, progressive neurodegenerative disorders such as Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA) that are characterized by α-synuclein (AS) aggregates in neurons or glia. PD and DLB feature neuronal AS-positive inclusions termed Lewy bodies (LB) whereas glial cytoplasmic inclusions (GCIs, Papp-Lantos bodies) are recognized as the defining hallmark of MSA. Furthermore, AS-positive cytoplasmic aggregates may also be seen in astroglial cells of PD/DLB and MSA brains. The glial AS-inclusions appear to trigger reduced trophic support resulting in neuronal loss. Moreover, microgliosis and astrogliosis can be found throughout the neurodegenerative brain and both are key players in the initiation and progression of ASP. In this review, we will highlight AS-dependent alterations of glial function and their impact on neuronal vulnerability thereby providing a detailed summary on the multifaceted role of glia in ASP.

Topics: alpha-Synuclein; Animals; Humans; Nerve Degeneration; Neurodegenerative Diseases; Neuroglia

Parkinson's disease belongs to a group of currently incurable neurodegenerative disorders characterized by the misfolding and accumulation of alpha-synuclein aggregates that are commonly known as synucleinopathies. Clinically, synucleinopathies are heterogeneous, reflecting the somewhat selective neuronal vulnerability characteristic of each disease. The precise molecular underpinnings of synucleinopathies remain unclear, but the process of aggregation of alpha-synuclein appears as a central event. However, there is still no consensus with respect to the toxic forms of alpha-synuclein, hampering our ability to use the protein as a target for therapeutic intervention. To decipher the molecular bases of synucleinopathies, it is essential to understand the complex triangle formed between the structure, function and toxicity of alpha-synuclein. Recently, important steps have been undertaken to elucidate the role of the protein in both physiological and pathological conditions. Here, we provide an overview of recent findings in the field of alpha-synuclein research, and put forward a new perspective over paradigms that persist in the field. Establishing whether alpha-synuclein has a causative role in all synucleinopathies will enable the identification of targets for the development of novel therapeutic strategies for this devastating group of disorders. Alpha-synuclein is the speculated cornerstone of several neurodegenerative disorders known as Synucleinopathies. Nevertheless, the mechanisms underlying the pathogenic effects of this protein remain unknown. Here, we review the recent findings in the three corners of alpha-synuclein biology - structure, function and toxicity - and discuss the enigmatic roads that have accompanied alpha-synuclein from the beginning. This article is part of a special issue on Parkinson disease.

Topics: alpha-Synuclein; Animals; Humans; Mutation; Neurodegenerative Diseases; Protein Aggregates; Protein Folding

α-Synuclein (αSyn) is a highly abundant neuronal protein whose exact structure and function are under debate. Misfolding and aggregation of this normally soluble, 140-residue polypeptide underlies a group of neurodegenerative disorders called synucleinopathies, including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). The αSyn field has focused increasing attention on the hypotheses that certain aggregates of αSyn may be directly toxic to the neurons in which they arise and/or that aggregates can be released from some neurons and diffuse by undefined mechanisms to other neurons to seed αSyn in the recipient cells, thus propagating neuropathology by a non-cell autonomous process ('pathogenic spread'). While intense interest in these hypotheses has led to new approaches and tools to model aspects of the disorders, it is important to analyze which molecular events initiate αSyn aggregation inside neurons in the first place. Here, we review new insights into how neuronal αSyn homeostasis may be maintained under physiological conditions but perturbed by pathological factors.

Topics: alpha-Synuclein; Brain; Cell Membrane; Homeostasis; Humans; Lewy Body Disease; Neurodegenerative Diseases; Neurons; Parkinson Disease; Protein Multimerization

The discovery of α-synuclein (α-syn) as a major component of Lewy bodies, neuropathological hallmark of Parkinson's disease (PD), dementia with Lewy bodies and of glial inclusions in multiple system atrophy initiated the investigation of α-syn as a biomarker in cerebrospinal fluid (CSF). Due to the involvement of the periphery in PD the quantification of α-syn in peripheral fluids such as serum, plasma and saliva has been investigated as well. We review how the development of multiple assays for the quantification of α-syn has yielded novel insights into the variety of α-syn species present in the different fluids; the optimal preanalytical conditions required for robust quantification and the potential clinical value of α-syn as biomarker. We also suggest future approaches to use of CSF α-syn in neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Biomarkers; Clinical Chemistry Tests; Humans; Neurodegenerative Diseases

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

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

Cyclin-dependent kinase 5 (Cdk5) is involved in proper neurodevelopment and brain function and serves as a switch between neuronal survival and death. Overactivation of Cdk5 is associated with many neurodegenerative disorders such as Alzheimer's or Parkinson's diseases. It is believed that in those diseases Cdk5 may be an important link between disease-initiating factors and cell death effectors. A common hallmark of neurodegenerative disorders is incorrect folding of specific proteins, thus leading to their intra- and extracellular accumulation in the nervous system. Abnormal Cdk5 signaling contributes to dysfunction of individual proteins and has a substantial role in either direct or indirect interactions of proteins common to, and critical in, different neurodegenerative diseases. While the roles of Cdk5 in α-synuclein (ASN) - tau or β-amyloid peptide (Aβ) - tau interactions are well documented, its contribution to many other pertinent interactions, such as that of ASN with Aβ, or interactions of the Aβ - ASN - tau triad with prion proteins, did not get beyond plausible hypotheses and remains to be proven. Understanding of the exact position of Cdk5 in the deleterious feed-forward loop critical for development and progression of neurodegenerative diseases may help designing successful therapeutic strategies of several fatal neurodegenerative diseases. Cyclin-dependent kinase 5 (Cdk5) is associated with many neurodegenerative disorders such as Alzheimer's or Parkinson's diseases. It is believed that in those diseases Cdk5 may be an important factor involved in protein misfolding, toxicity and interaction. We suggest that Cdk5 may contribute to the vicious circle of neurotoxic events involved in the pathogenesis of different neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Cyclin-Dependent Kinase 5; Humans; Neurodegenerative Diseases; Protein Folding; Signal Transduction; tau Proteins

Disease-modifying alternatives are sorely needed for the treatment of neurodegenerative disorders, a group of diseases that afflict approximately 50 million Americans annually. Immunotherapy is one of the most developed approaches in this direction. Vaccination against amyloid-β, α-synuclein, or tau has been extensively explored, specially as the discovery that these proteins may propagate cell-to-cell and be accessible to antibodies when embedded into the plasma membrane or in the extracellular space. Likewise, the use of passive immunization approaches with specific antibodies against abnormal conformations of these proteins has also yielded promising results. The clinical development of immunotherapies for Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, dementia with Lewy bodies, and other neurodegenerative disorders is a field in constant evolution. Results to date suggest that immunotherapy is a promising therapeutic approach for neurodegenerative diseases that progress with the accumulation and prion-like propagation of toxic protein aggregates. Here we provide an overview of the most novel and relevant immunotherapeutic advances targeting amyloid-β in Alzheimer’s disease, α-synuclein in Alzheimer’s disease and Parkinson’s disease, and tau in Alzheimer’s disease and frontotemporal dementia.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Immunotherapy; Neurodegenerative Diseases; Parkinson Disease; tau Proteins

Alpha-synuclein aggregation is associated with Parkinson's disease and other neurodegenerative disorders termed synucleinopathies. The sequence of alpha-synuclein has a remarkable amount of lysines, which may be a target for modifications by several aldehydes found at increased concentration in parkinsonian brains. The involved aldehydes are the dopamine metabolite 3,4-dihydroxyphenylacetaldehyde, the lipid peroxidation products 4-hydroxynonenal, acrolein and malondialdehyde, and advanced glycation end-products. Moreover, both relative expression levels and enzymatic activity of aldehyde dehydrogenases, which are responsible for aldehydes detoxification in cells, are altered in Parkinson's disease brains. The effects of aldehyde modifications can include: (i) a perturbation in the equilibrium of cytosolic and membrane-bound alpha-synuclein, that may alter protein function and lead to aggregation; (ii) the reduction of alpha-synuclein ubiquitination and SUMOylation, affecting its cellular localization and clearance; (iii) a decreased susceptibility to cleavage at specific sites by extracellular proteases; (iv) a reduced availability of identified lysine acetylation sites; (v) the production of toxic oligomeric alpha-synuclein-aldehyde species, able to damage lipid membranes and transmissible from unhealthy to healthy neurons. All of these observations point to a complex interaction between alpha-synuclein and aldehydes in brain, which may lead to the accumulation of dysfunctional alpha-synuclein and its oligomerization.

Topics: 3,4-Dihydroxyphenylacetic Acid; Aldehydes; alpha-Synuclein; Brain; Dopamine; Humans; Lysine; Metabolism; Neurodegenerative Diseases; Neurons

Cardiac meta-iodobenzylguanidine (MIBG) uptake on (123)I-MIBG cardiac scintigraphy is reduced in patients with Lewy body disease such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and pure autonomic failure, and has been reported to be useful for differentiating PD from other parkinsonian syndromes, as well as DLB from Alzheimer disease (AD). Postmortem studies have shown that the number of tyrosine hydroxylase (TH)-immunoreactive nerve fibers of the heart was decreased in pathologically-confirmed Lewy body disease, supporting the findings of reduced cardiac MIBG uptake in Lewy body diseases. Now, reduced cardiac MIBG uptake can be a potential biomarker for the presence of Lewy bodies in the nervous system. (123)I-MIBG cardiac scintigraphy can allow us to determine the presence of Lewy bodies.

Topics: 3-Iodobenzylguanidine; alpha-Synuclein; Animals; Biomarkers; Heart; Humans; Neurodegenerative Diseases; Radionuclide Imaging; Radiopharmaceuticals

Several decades ago, a mysterious transmissible agent was found responsible for a group of progressive and lethal encephalopathies affecting the nervous system of both animals and humans. This infectious agent showed a strain-encoded manner of inheritance even though it lacked nucleic acids. The identification of infectious proteins resolved this apparent conundrum. Misfolded infectious protein particles, or prions, were found to exist as conformational isomers with a unique fingerprint that can be faithfully passaged to next generations. Protein-based strain-encoded inheritance is characterized by strain-specific infectivity and symptomatology. It is found in diverse organisms, such as yeast, fungi, and mammals. Now, this concept is revisited to examine the pathological role of amyloid proteins involved in neurodegenerative diseases where it might underlie certain types of dementia and motor-related neurodegenerative disorders. Given the discovery of the SNCA gene and the identification of its gene product, ɑ-synuclein (ɑ-SYN), as the main histopathological component of Parkinson's disease, dementia with Lewy bodies and multiple system atrophy, the scientific community was left puzzled by the fact that a single protein appeared to be involved in different diseases with diverging clinical phenotypes. Recent studies are now indicating that ɑ-SYN may act in a way similar to prions and that ɑ-SYN misfolded structural variants may behave as strains with distinct biochemical and functional properties inducing specific phenotypic traits, which might finally provide an explanation for the clinical heterogeneity observed between Parkinson's disease, MSA, and dementia with Lewy bodies patients. These crucial new findings may pave the way for unexplored therapeutic avenues and identification of new potential biomarkers. Parkinson's disease and other synucleinopathies share ɑ-synuclein deposits as a common histopathological hallmark. New and ongoing developments are now showing that variations in the aggregation process and the formation of ɑ-synuclein strains may be paralleled by the development of distinct synucleinopathies. Here, we review the recent developments and the role of strains in synucleinopathies. This article is part of a special issue on Parkinson disease.

Topics: alpha-Synuclein; Animals; Dementia; Genetic Variation; Humans; Lewy Body Disease; Multiple System Atrophy; Neurodegenerative Diseases; Parkinson Disease

It is now established that α-synuclein can be physiologically secreted to the extracellular space. In this sense, mechanisms that govern the secretion of the protein may be of importance in the initiation and progress of synucleinopathies. It is possible that increased secretion may aid the formation of toxic seeds extracellularly. Alternatively, reduced presence of extracellular α-synuclein due to impaired secretion may increase the intracellular load and trigger intracellular seeding. Once outside, α-synuclein can exert various paracrine actions on neighboring cells again by mechanisms that have not been fully elucidated. It has been demonstrated that, when applied extracellularly, α-synuclein species can induce multiple neurotoxic and inflammatory responses, and aid the transmission of pathology between neurons. Still, the exact mechanism(s) by which secreted α-synuclein affects the homeostasis of other neurons is still not well understood. A portion of α-synuclein has been shown to be associated with the surface and lumen of exosomes which can transfer it to the surrounding cells, and potentially trigger seeding. Interestingly, increased exosome release has been linked to pathological situations of lysosomal dysfunction as observed in Parkinson's disease (PD). However, the possibility that the observed α-synuclein pathology spread is attributable to the passive diffusion of the initial injected α-synuclein strains cannot be excluded. Importantly, most of the studies that have so far addressed the role of extracellular α-synuclein have not employed naturally secreted forms of the protein. It is plausible that deregulation in the normal processing of secreted α-synuclein may aid the formation of "toxic" species and as such it may also be a causative risk factor for PD. In this capacity, elucidation of the underlying mechanisms that regulate the protein-levels of extracellular α-synuclein becomes essential. Such mechanisms could involve its proteolytic clearance from the extracellular milieu.

Topics: alpha-Synuclein; Animals; Exocytosis; Humans; Neurodegenerative Diseases

α-synuclein is normally situated in the nerve terminal but it accumulates and aggregates in axons and cell bodies in synucleinopathies such as Parkinson's disease. The conformational changes occurring during α-synucleins aggregation process affects its interactions with other proteins and its subcellular localization. This review focuses on interaction partners of α-synuclein within different compartments of the cell with a focus on those preferentially binding aggregated α-synuclein. The aggregation state of α-synuclein also affects its catabolism and we hypothesize impaired macroautophagy is involved neuronal excretion of α-synuclein species responsible for the prion-like spreading of α-synuclein pathology.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases

There has been an explosion in the number of papers discussing the hypothesis of 'pathogenic spread' in neurodegenerative disease - the idea that abnormal forms of disease-associated proteins, such as tau or α-synuclein, physically move from neuron to neuron to induce disease progression. However, whether inter-neuronal spread of protein aggregates actually occurs in humans and, if so, whether it causes symptom onset remain uncertain. Even if pathogenic spread is proven in humans, it is unclear how much this would alter the specific therapeutic approaches that are in development. A critical appraisal of this increasingly popular hypothesis thus seems both important and timely.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Neurons; Protein Aggregation, Pathological; Protein Transport; tau Proteins

Therapeutic agents are urgently required to cure several common and fatal neurodegenerative disorders caused by protein misfolding and aggregation, including amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD). Protein disaggregases that reverse protein misfolding and restore proteins to native structure, function, and localization could mitigate neurodegeneration by simultaneously reversing 1) any toxic gain of function of the misfolded form and 2) any loss of function due to misfolding. Potentiated variants of Hsp104, a hexameric AAA+ ATPase and protein disaggregase from yeast, have been engineered to robustly disaggregate misfolded proteins connected with ALS (e.g., TDP-43 and FUS) and PD (e.g., α-synuclein). However, Hsp104 has no metazoan homologue. Metazoa possess protein disaggregase systems distinct from Hsp104, including Hsp110, Hsp70, and Hsp40, as well as HtrA1, which might be harnessed to reverse deleterious protein misfolding. Nevertheless, vicissitudes of aging, environment, or genetics conspire to negate these disaggregase systems in neurodegenerative disease. Thus, engineering potentiated human protein disaggregases or isolating small-molecule enhancers of their activity could yield transformative therapeutics for ALS, PD, and AD.

Topics: alpha-Synuclein; Animals; DNA-Binding Proteins; Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Humans; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregates; Protein Engineering; Protein Folding; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins

Alpha-synuclein (α-syn) is a highly conserved protein encoded by the SNCA gene and is expressed uniquely in neurons of both the central and peripheral nervous systems (CNS and PNS). α-Syn is known to cause sporadic and familial forms of Parkinson's disease (PD). However, the role for neuronal expression of α-syn in the first place remains unknown. We review and discuss recently published work that suggests a novel role for α-syn expression in neurons as a restriction factor that inhibits virus transmission from the PNS to the CNS. The potential new role for α-syn expression as a virus inhibitor may provide new approaches to understand the pathogenesis of PD and provide novel approaches to prevent and treat this common neurodegenerative disease.

Topics: alpha-Synuclein; Animals; Central Nervous System; Gene Expression; Humans; Neurodegenerative Diseases; Neurons; Peripheral Nervous System

Intracellular abnormal protein deposits, such as tau, α-synuclein and TDP-43, are the hallmark of many neurodegenerative diseases, and the distributions of these pathological proteins are closely correlated with disease symptoms and progression. A growing body of evidence strongly suggests that these abnormal proteins have prion-like properties: they convert normal proteins into abnormal forms, self-propagate through neuronal networks, and then spread in the brain. This prion-like propagation of abnormal proteins may account for the diversity, selective degeneration and disease progression seen in neurodegenerative diseases, although the molecular mechanism remains uncertain the molecular details of this mechanism. This review describes recent studies on prion-like properties of abnormal proteins in vitro, in cells and in animal experimental models.

Topics: alpha-Synuclein; Animals; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Prion Proteins; Prions; Protein Multimerization

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

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

Gaucher disease, the most common lysosomal storage disease, is caused by a recessively inherited deficiency in glucocerebrosidase and subsequent accumulation of toxic lipid substrates. Heterozygous mutations in the lysosomal glucocerebrosidase gene (GBA1) have recently been recognized as the highest genetic risk factor for the development of α-synuclein aggregation disorders ("synucleinopathies"), including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Despite the wealth of experimental, clinical and genetic evidence that supports the association between mutant genotypes and synucleinopathy risk, the precise mechanisms by which GBA1 mutations lead to PD and DLB remain unclear. Decreased glucocerebrosidase activity has been demonstrated to promote α-synuclein misprocessing. Furthermore, aberrant α-synuclein species have been reported to downregulate glucocerebrosidase activity, which further contributes to disease progression. In this review, we summarize the recent findings that highlight the complexity of this pathogenetic link and how several pathways that connect glucocerebrosidase insufficiency with α-synuclein misprocessing have emerged as potential therapeutic targets. From a translational perspective, we discuss how various therapeutic approaches to lysosomal dysfunction have been explored for the treatment of GBA1-related synucleinopathies, and potentially, for non-GBA1-associated neurodegenerative diseases. In summary, the link between GBA1 and synucleinopathies has become the paradigm of how the study of a rare lysosomal disease can transform the understanding of the etiopathology, and hopefully the treatment, of a more prevalent and multifactorial disorder.

Topics: alpha-Synuclein; Gaucher Disease; Glucosylceramidase; Humans; Mutation; Neurodegenerative Diseases

Several neurodegenerative diseases such as transmissible spongiform encephalopathies, Alzheimer's and Parkinson's diseases are caused by the conversion of cellular proteins to a pathogenic conformer. Despite differences in the primary structure and subcellular localization of these proteins, which include the prion protein, α-synuclein and amyloid precursor protein (APP), striking similarity has been observed in their ability to seed and convert naïve protein molecules as well as transfer between cells. This review aims to cover what is known about the intracellular trafficking of these proteins as well as their degradation mechanisms and highlight similarities in their movement through the endocytic pathway that could contribute to the pathogenic conversion and seeding of these proteins which underlies the basis of these diseases.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Humans; Neurodegenerative Diseases; Prions; Protein Transport; Proteolysis

Misfolded protein aggregates are the hallmark of several neurodegenerative diseases in humans. The main protein constituent of these aggregates and the regions within the brain that are affected differ from one neurodegenerative disorder to another. A plethora of reports suggest that distinct diseases have in common the ability of protein aggregates to spread and amplify within the central nervous system. This review summarizes briefly what is known about the nature of the protein aggregates that are infectious and the reason they are toxic to cells. The chameleon property of polypeptides which aggregation into distinct high-molecular weight assemblies is associated to different diseases, in particular, that of alpha-synuclein which aggregation is the hallmark of distinct synucleinopathies, is discussed. Finally, strategies targeting the formation and propagation of structurally distinct alpha-synuclein assemblies associated to different synucleinopathies are presented and their therapeutic and diagnostic potential is discussed.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Humans; Neurodegenerative Diseases; Protein Aggregation, Pathological; Proteostasis Deficiencies; tau Proteins

Mammalian cells remove misfolded proteins using various proteolytic systems, including the ubiquitin (Ub)-proteasome system (UPS), chaperone mediated autophagy (CMA) and macroautophagy. The majority of misfolded proteins are degraded by the UPS, in which Ub-conjugated substrates are deubiquitinated, unfolded and cleaved into small peptides when passing through the narrow chamber of the proteasome. The substrates that expose a specific degradation signal, the KFERQ sequence motif, can be delivered to and degraded in lysosomes via the CMA. Aggregation-prone substrates resistant to both the UPS and the CMA can be degraded by macroautophagy, in which cargoes are segregated into autophagosomes before degradation by lysosomal hydrolases. Although most misfolded and aggregated proteins in the human proteome can be degraded by cellular protein quality control, some native and mutant proteins prone to aggregation into β-sheet-enriched oligomers are resistant to all known proteolytic pathways and can thus grow into inclusion bodies or extracellular plaques. The accumulation of protease-resistant misfolded and aggregated proteins is a common mechanism underlying protein misfolding disorders, including neurodegenerative diseases such as Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), prion diseases and Amyotrophic Lateral Sclerosis (ALS). In this review, we provide an overview of the proteolytic pathways in neurons, with an emphasis on the UPS, CMA and macroautophagy, and discuss the role of protein quality control in the degradation of pathogenic proteins in neurodegenerative diseases. Additionally, we examine existing putative therapeutic strategies to efficiently remove cytotoxic proteins from degenerating neurons.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Animals; Autophagy; DNA-Binding Proteins; Humans; Huntingtin Protein; Huntington Disease; Lysosomes; Molecular Targeted Therapy; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Prion Diseases; Proteasome Endopeptidase Complex; Proteolysis; Proteostasis Deficiencies; PrPSc Proteins; Superoxide Dismutase; tau Proteins; Ubiquitin

In a number of neurological diseases including Parkinson's disease (PD), α-synuclein is aberrantly folded, forming abnormal oligomers, and amyloid fibrils within nerve cells. Strong evidence exists for the toxicity of increased production and aggregation of α-synuclein in vivo. The toxicity of α-synuclein is popularly attributed to the formation of "toxic oligomers": a heterogenous and poorly characterized group of conformers that may share common molecular features. This review presents the available evidence on the properties of α-synuclein oligomers and the potential molecular mechanisms of their cellular disruption. Toxic α-synuclein oligomers may impact cells in a number of ways, including the disruption of membranes, mitochondrial depolarization, cytoskeleton changes, impairment of protein clearance pathways, and enhanced oxidative stress. We also examine the relationship between α-synuclein toxic oligomers and amyloid fibrils, in the light of recent studies that paint a more complex picture of α-synuclein toxicity. Finally, methods of studying and manipulating oligomers within cells are described.

Topics: alpha-Synuclein; Amyloid; Animals; Humans; Mutation; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Multimerization

Parkinson's disease is the second most common neurodegenerative disease which affects almost 1 percent of the population above the age of 60. It is is characterized by loss of dopaminergic neurons in the striatum and substantia nigra, coupled with the formation of intracellular Lewy bodies in degenerating neurons. Recent evidence suggests endoplasmic reticulum stress as a common and prominent occurrence in the progression of Parkinson's disease pathogenesis in the affected human brain. One of the cellular defense mechanism to combat endoplasmic reticulum stress due to excessive protein accumulation is through activation of the unfolded protein response pathway. In this review we focus on the impact and role of this unfolded protein response as a causative factor of Parkinson's disease leading to neurodegeneration.

Topics: alpha-Synuclein; Animals; Brain; Humans; Neurodegenerative Diseases; Parkinson Disease; Unfolded Protein Response

Insoluble and fibrillar forms of α-synuclein are the major components of Lewy bodies, a hallmark of several sporadic and inherited neurodegenerative diseases known as synucleinopathies. α-Synuclein is a natural unfolded and aggregation-prone protein that can be degraded by the ubiquitin-proteasomal system and the lysosomal degradation pathways. α-Synuclein is a target of the main cellular proteolytic systems, but it is also able to alter their function further, contributing to the progression of neurodegeneration. Aging, a major risk for synucleinopathies, is associated with a decrease activity of the proteolytic systems, further aggravating this toxic looping cycle. Here, the current literature on the basic aspects of the routes for α-synuclein clearance, as well as the consequences of the proteolytic systems collapse, will be discussed. Finally, particular focus will be given to the sirtuins's role on proteostasis regulation, since their modulation emerged as a promising therapeutic strategy to rescue cells from α-synuclein toxicity. The controversial reports on the potential role of sirtuins in the degradation of α-synuclein will be discussed. Connection between sirtuins and proteolytic systems is definitely worth of further studies to increase the knowledge that will allow its proper exploration as new avenue to fight synucleinopathies.

Topics: alpha-Synuclein; Animals; Autophagy; Humans; Neurodegenerative Diseases; Proteolysis; Sirtuins; Ubiquitination

The gold standard for diagnosis of neurodegenerative diseases (ie, Alzheimer disease, frontotemporal dementia, Parkinson disease, dementia with Lewy bodies, amyotrophic lateral sclerosis) is neuropathologic examination at autopsy. As such, laboratory studies play a central role in antemortem diagnosis of these conditions and their differentiation from the neuroinflammatory, infectious, toxic, and other nondegenerative etiologies (eg, rapidly progressive dementias) that are encountered in neuropsychiatric practice. This article summarizes the use of cerebrospinal fluid (CSF) laboratory studies in the diagnostic evaluation of dementia syndromes and emerging CSF biomarkers specific for underlying neuropathology in neurodegenerative disease research.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Brain; Cerebrospinal Fluid; Dementia; Disease Progression; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Neuropsychiatry

A number of cerebrospinal fluid (CSF) biomarkers are currently used for the diagnosis of dementia. Opposite changes in the level of amyloid-β(1-42) versus total tau and phosphorylated-tau181 in the CSF reflect the specific pathology of Alzheimer's disease (AD) in the brain. This panel of biomarkers has proven to be effective to differentiate AD from controls and from the major types of neurodegenerative dementia, and to evaluate the progression from mild cognitive impairment to AD. In the absence of specific biomarkers reflecting the pathologies of the other most common forms of dementia, such as Lewy Body disease, Frontotemporal lobar degeneration, Creutzfeldt-Jakob disease, etc., the evaluation of biomarkers of AD pathology is used, attempting to exclude rather than to confirm AD. Other biomarkers included in the common clinical practice do not clearly relate to the underlying pathology: progranulin (PGRN) is a selective marker of frontotemporal dementia with mutations in the PGRN gene; the 14-3-3 protein is a highly sensitive and specific marker for Creutzfeldt-Jakob disease, but has to be used carefully in differentiating rapid progressive dementia; and α-synuclein is an emerging candidate biomarker of the different forms of synucleinopathy. This review summarizes several biomarkers of neurodegenerative dementia validated based on the neuropathological processes occurring in brain tissue. Notwithstanding the paucity of pathologically validated biomarkers and their high analytical variability, the combinations of these biomarkers may well represent a key and more precise analytical and diagnostic tool in the complex plethora of degenerative dementia.

Topics: 14-3-3 Proteins; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Dementia; Diagnosis, Computer-Assisted; Diagnosis, Differential; Humans; Neurodegenerative Diseases; Peptide Fragments; Reproducibility of Results; Sensitivity and Specificity; tau Proteins

Nervous system controls all the organs in the living like a symphony. In this chapter, the mechanism of neuronal death in aged is discussed in relation to oxidative stress. Polyunsaturated fatty acid (PUFA) is known to be rich in the membranous component of the neurons and plays an important role in maintaining the neuronal functions. Recent reports revealed that oxidation of omega-3 and omega-6 PUFAs, such as docosahexaenoic acid (DHA) and arachidonic acid (ARA), are potent antioxidant but simultaneously, their oxidation products are potentially toxic. In this chapter, the existence of early oxidation products of PUFA is examined in the samples from neurodegenerative disorders and the cellular model. Accumulation of proteins with abnormal conformation is suggested to induce neuronal death by disturbance of proteolysis and mitochondrial function. The role of lipid peroxide and lipid-derived aldehyde adduct proteins is discussed in relation to brain ageing and age-related neurodegeneration.

Topics: alpha-Synuclein; Brain; Fatty Acids, Omega-3; Fatty Acids, Unsaturated; Humans; Lipid Peroxides; Neurodegenerative Diseases; Neurons; Oxidative Stress

Rapid eye movement (REM) sleep behavior disorder (RBD) is defined as a parasomnia characterized by loss of REM sleep-associated atonia and the presence of motor activity during dreaming typically presenting with an aggressive dream content. Epidemiological data on the prevalence of RBD are insufficient but it can be idiopathic or symptomatic. A video-audio polysomnography is essential for diagnosis. Clonazepam and melatonin are available as pharmaceutical treatment. Recent studies demonstrated that individuals suffering from idiopathic RBD carry a high specific risk (up to 80 %) for developing a neurodegenerative disorder of the α-synucleinopathy type (e.g. Parkinson's disease, dementia with Lewy bodies and multiple system atrophy) within 10-20 years. The current article provides a short overview of symptoms, epidemiology, pathophysiology, diagnosis and therapy of RBD.

Topics: alpha-Synuclein; Anticonvulsants; Humans; Neurodegenerative Diseases; Polysomnography; Prodromal Symptoms; REM Sleep Behavior Disorder

Protein misfolding is an intrinsic aspect of normal folding within the complex cellular environment. Its effects are minimized in living system by the action of a range of protective mechanisms including molecular chaperones and quality control systems. According to the current growing research, protein misfolding is a recognized key feature of most neurodegenerative diseases. Extensive biochemical, neuropathological, and genetic evidence suggest that the cerebral accumulation of amyloid fibrils is the central event in the pathogenesis of neurodegenerative disorders. In the first part of this review we have discussed the general course of action of folding and misfolding of the proteins. Later part of this review gives an outline regarding the role of protein misfolding in the molecular and cellular mechanisms in the pathogenesis of Alzheimer's and Parkinson along with their treatment possibilities. Finally, we have mentioned about the recent findings in neurodegenerative diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Autophagy; Heat-Shock Proteins; Humans; Molecular Chaperones; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Parkinson Disease; Phosphorylation; Plaque, Amyloid; Proteasome Endopeptidase Complex; Protein Folding; Protein Processing, Post-Translational; Ubiquitination; Unfolded Protein Response

Neurodegenerative diseases are characterized by the aggregation of misfolded proteins in the brain. Among these disorders are the prion diseases, which are transmissible, and in which the misfolded proteins ("prions") are also the infectious agent. Increasingly, it appears that misfolded proteins in Alzheimer and Parkinson diseases and the tauopathies also propagate in a "prion-like" manner. However, the association between prion formation, spread, and neurotoxicity is not clear. Recently, we showed that in prion disease, protein misfolding leads to neurodegeneration through dysregulation of generic proteostatic mechanisms, specifically, the unfolded protein response. Genetic and pharmacological manipulation of the unfolded protein response was neuroprotective despite continuing prion replication, hence dissociating this from neurotoxicity. The data have clear implications for treatment across the spectrum of these disorders, targeting pathogenic processes downstream of protein misfolding.

Topics: Adenine; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; eIF-2 Kinase; Humans; Indoles; Neurodegenerative Diseases; Parkinson Disease; Prion Diseases; Prions; Protein Conformation; Protein Kinase Inhibitors; tau Proteins; Tauopathies; Unfolded Protein Response

Cytoplasmic localization and possession of two deacetylase domains and a ubiquitin-binding domain make histone deacetylase 6 (HDAC6) a unique histone deacetylase. HDAC6 interacts with a number of proteins in the cytoplasm. Some of these proteins can be deacetylated by HDAC6 deacetylase activity. Others can affect HDAC6 functions by modulating its catalytic activity or ubiquitin-binding capability. Over the last decade, HDAC6 has been shown to play important roles in the aggresome-autophagy pathway, which selectively targets on protein aggregates or damaged organelles for their accumulation and clearance in cells. HDAC6-interacting partners are integral components in this pathway with regard to their regulatory roles through interaction with HDAC6. The aggresome-autophagy pathway appears to be an attractive therapeutic target for the treatment of neurodegenerative diseases as accumulation of protein aggregates are hallmarks in these diseases. In the current review, I discuss the molecular details of how HDAC6 and its interacting partners regulate each individual step in the aggresome-autophagy pathway and also provide perspectives of how HDAC6 can be targeted in treating neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Autophagy; Histone Deacetylase 6; Histone Deacetylases; Humans; Microtubule-Organizing Center; Mitophagy; Neurodegenerative Diseases; Protein Interaction Maps; Protein Transport; Proteolysis; tau Proteins; Ubiquitin-Protein Ligases; Ubiquitination

Several neurodegenerative diseases involve loss of catecholamine neurons-Parkinson disease is a prototypical example. Catecholamine neurons are rare in the nervous system, and why they are vulnerable in PD and related disorders has been mysterious. Accumulating evidence supports the concept of "autotoxicity"-inherent cytotoxicity of catecholamines and their metabolites in the cells in which they are produced. According to the "catecholaldehyde hypothesis" for the pathogenesis of Parkinson disease, long-term increased build-up of 3,4-dihydroxyphenylacetaldehyde (DOPAL), the catecholaldehyde metabolite of dopamine, causes or contributes to the eventual death of dopaminergic neurons. Lewy bodies, a neuropathologic hallmark of PD, contain precipitated alpha-synuclein. Bases for the tendency of alpha-synuclein to precipitate in the cytoplasm of catecholaminergic neurons have also been mysterious. Since DOPAL potently oligomerizes and aggregates alpha-synuclein, the catecholaldehyde hypothesis provides a link between alpha-synucleinopathy and catecholamine neuron loss in Lewy body diseases. The concept developed here is that DOPAL and alpha-synuclein are nodes in a complex nexus of interacting homeostatic systems. Dysfunctions of several processes, including decreased vesicular sequestration of cytoplasmic catecholamines, decreased aldehyde dehydrogenase activity, and oligomerization of alpha-synuclein, lead to conversion from the stability afforded by negative feedback regulation to the instability, degeneration, and system failure caused by induction of positive feedback loops. These dysfunctions result from diverse combinations of genetic predispositions, environmental exposures, stress, and time. The notion of catecholamine autotoxicity has several implications for treatment, disease modification, and prevention. Conversely, disease modification clinical trials would provide key tests of the catecholaldehyde hypothesis.

Topics: 3,4-Dihydroxyphenylacetic Acid; alpha-Synuclein; Animals; Apoptosis; Catecholamines; Humans; Lipid Peroxidation; Neurodegenerative Diseases; Neurons; Oxidation-Reduction; Parkinson Disease

Protein homeostasis, or proteostasis, is the process of maintaining the conformational and functional integrity of the proteome. The failure of proteostasis can result in the accumulation of non-native proteins leading to their aggregation and deposition in cells and in tissues. The amyloid fibrillar aggregation of the protein α-synuclein into Lewy bodies and Lewy neuritis is associated with neurodegenerative diseases classified as α-synucleinopathies, which include Parkinson's disease and dementia with Lewy bodies. The small heat-shock proteins (sHsps) are molecular chaperones that are one of the cell's first lines of defence against protein aggregation. They act to stabilise partially folded protein intermediates, in an ATP-independent manner, to maintain cellular proteostasis under stress conditions. Thus, the sHsps appear ideally suited to protect against α-synuclein aggregation, yet these fail to do so in the context of the α-synucleinopathies. This review discusses how sHsps interact with α-synuclein to prevent its aggregation and, in doing so, highlights the multi-faceted nature of the mechanisms used by sHsps to prevent the fibrillar aggregation of proteins. It also examines what factors may contribute to α-synuclein escaping the sHsp chaperones in the context of the α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Heat-Shock Proteins, Small; Humans; Molecular Chaperones; Neurodegenerative Diseases

Neurodegenerative diseases characterized by the presence of α-synuclein-a hallmark of pathologic inclusions termed Lewy bodies-include Parkinson's disease, dementia with Lewy bodies, and multiple-system atrophy. Although motor symptoms are related to the altered presynaptic dopaminergic function in these diseases, the appearance of α-synuclein inclusions precedes the involvement of the nigrostriatal dopaminergic pathway. Hence, the most accurate and earliest definition of premotor Parkinson's disease ought to rely on imaging α-synuclein rather than dopaminergic changes. Moreover, dopaminergic imaging has been controversial in monitoring the effects of investigational disease-modifying drugs. For these clinical trials, intense interest in longitudinally imaging α-synuclein as the primary pathologic process has led to efforts toward developing a suitable radiotracer for this key protein. An overview of the present α-synuclein radiotracer development scenario is presented here.

Topics: alpha-Synuclein; Animals; Humans; Molecular Imaging; Neurodegenerative Diseases; Parkinson Disease; Positron-Emission Tomography

Neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, are characterized by the abnormal aggregation of a small number of intracellular proteins, with tau and α-synuclein being the most commonly affected. Until recently, the events leading to aggregate formation were believed to be entirely cell-autonomous, with protein misfolding occurring independently in many cells. It is now believed that protein aggregates form in a small number of brain cells, from which they propagate intercellularly through templated recruitment, reminiscent of the mechanisms by which prions spread through the nervous system.

Topics: alpha-Synuclein; Central Nervous System; Humans; Neurodegenerative Diseases; Prions; Proteostasis Deficiencies; tau Proteins

In Parkinson's disease and some atypical Parkinson's syndromes, aggregation of the α-synuclein protein (α-syn) has been linked to neurodegeneration. Many triggers for pathological α-syn aggregation have been identified, including port-translational modifications, oxidative stress and raised metal ions, such as Ca2+. Recently, it has been found using cell culture models that transient increases of intracellular Ca2+ induce cytoplasmic α-syn aggregates. Ca2+-dependent α-syn aggregation could be blocked by the Ca2+ buffering agent, BAPTA-AM, or by the Ca2+ channel blocker, Trimethadione. Furthermore, a greater proportion of cells positive for aggregates occurred when both raised Ca2+ and oxidative stress were combined, indicating that Ca2+ and oxidative stress cooperatively promote α-syn aggregation. Current on-going work using a unilateral mouse lesion model of Parkinson's disease shows a greater proportion of calbindin-positive neurons survive the lesion, with intracellular α-syn aggregates almost exclusively occurring in calbindin-negative neurons. These and other recent findings are reviewed in the context of neurodegenerative pathologies and suggest an association between raised Ca2+, α-syn aggregation and neurotoxicity.

Topics: alpha-Synuclein; Animals; Calcium; Humans; Intracellular Space; Neurodegenerative Diseases; Protein Binding; Protein Multimerization

The accumulation of α-synuclein aggregates is the hallmark of Parkinson's disease, and more generally of synucleinopathies. The accumulation of tau aggregates however is classically found in the brains of patients with dementia, and this type of neuropathological feature specifically defines the tauopathies. Nevertheless, in numerous cases α-synuclein positive inclusions are also described in tauopathies and vice versa, suggesting a co-existence or crosstalk of these proteinopathies. Interestingly, α-synuclein and tau share striking common characteristics suggesting that they may work in concord. Tau and α-synuclein are both partially unfolded proteins that can form toxic oligomers and abnormal intracellular aggregates under pathological conditions. Furthermore, mutations in either are responsible for severe dominant familial neurodegeneration. Moreover, tau and α-synuclein appear to promote the fibrillization and solubility of each other in vitro and in vivo. This suggests that interactions between tau and α-synuclein form a deleterious feed-forward loop essential for the development and spreading of neurodegeneration. Here, we review the recent literature with respect to elucidating the possible links between α-synuclein and tau.

Topics: alpha-Synuclein; Animals; Humans; Nerve Degeneration; Neurodegenerative Diseases; tau Proteins

It has been demonstrated that both oligomerisation and accumulation of α-synuclein (ASN) are the key molecular processes involved in the pathophysiology of neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease and other synucleinopathies. Alterations of ASN expression and impairment of its degradation can lead to the formation of intracellular deposits of this protein, called Lewy bodies. Overexpressed or misfolded ASN could be secreted to the extracellular space. Today the prion-like transmission of ASN oligomers to neighbouring cells is believed to be responsible for protein modification and propagation of neurodegeneration in the brain. It was presented that oxidative/nitrosative stress may play a key role in ASN secretion and spread of ASN pathology. Moreover, ASN-evoked protein oxidation, nitration and nitrosylation lead to disturbances in synaptic transmission and cell death. The interaction of secreted ASN with other amyloidogenic proteins and its involvement in irreversible mitochondrial disturbances and oxidative stress were also described. A better understanding of the mechanisms of ASN secretion and dysfunction may help to explain the molecular mechanisms of neurodegeneration and may be the basis for the development of novel therapeutic strategies.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Nitric Oxide; Nitrosation; Oxidative Stress; Reactive Nitrogen Species

Synucleinopathies include Parkinson's disease, dementia with Lewy bodies, Lewy body variant of Alzheimer's disease and multiple system atrophy, among the most relevant diseases. All of these diseases are characterized by the presence of amyloid inclusions in neurons, which are rich in the aggregate α-synuclein protein. What is the biological mechanism concerned in the gain-of-function that implicates the participation of α-synuclein in these diseases? Post-translational modifications of α-synuclein induced by nitroxidative stress are a relevant hypothesis that may explain many of the experimental data. We will review the biophysical and biochemical properties of α-synuclein, methionine residues oxidation, nitration and oxidation of tyrosine residues in α-synuclein, and modifications of α-synuclein mediated by proteins and lipids under nitroxidative stress conditions. The biological consequences of these modifications are analyzed in terms of the properties of α-synuclein oligomerization and fibrillation, degradation of α-synuclein and the implications in the immunological response.

Topics: alpha-Synuclein; Amino Acid Sequence; Humans; Molecular Sequence Data; Neurodegenerative Diseases; Nitro Compounds; Oxidation-Reduction; Protein Multimerization; Protein Processing, Post-Translational

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Calcium; Drug Design; GTP-Binding Protein alpha Subunits; GTP-Binding Proteins; Humans; Ligands; Mice; Molecular Targeted Therapy; Neurodegenerative Diseases; Protein Glutamine gamma Glutamyltransferase 2; Rats; Receptors, G-Protein-Coupled; Signal Transduction; Transglutaminases

Many neurodegenerative diseases are characterized by the progressive accumulation of aggregated protein. Recent evidence suggests the prion-like propagation of protein misfolding underlies the spread of pathology observed in these diseases. This review traces our understanding of the mechanisms that underlie this phenomenon and discusses related therapeutic strategies that derive from it.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Humans; Neurodegenerative Diseases; Neurons; Prions; Protein Conformation

High hydrostatic pressure (HHP) is a valuable tool to study processes such as protein folding, protein hydration and protein-protein interactions. HHP is a nondestructive technique because it reversibly affects internal cavities excluded from the solvent present in the hydrophobic core of proteins. HHP allows the solvation of buried amino acid side chains, thus shifting the equilibrium towards states of the studied molecule or molecular ensemble that occupy smaller volumes. HHP has long been used to dissociate multimeric proteins and protein aggregates and allows investigation of intermediate folding states, some of which are formed by proteins involved in human degenerative diseases, such as spongiform encephalopathies and Parkinson's disease, as well as cancer. When coupled with nuclear magnetic resonance and spectroscopic methods such as infrared and fluorescence spectroscopy, HHP treatment facilitates the understanding of protein folding and misfolding processes; the latter is related to protein aggregation into amyloid or amorphous species. In this review, we will address how HHP provides information about intermediate folding states and the aggregation processes of p53, which is related to cancer, and prion proteins, transthyretin and α-synuclein, which are related to human degenerative diseases.

Topics: alpha-Synuclein; Amyloid; Animals; Humans; Hydrostatic Pressure; Neoplasms; Neurodegenerative Diseases; Nuclear Magnetic Resonance, Biomolecular; Prealbumin; Prions; Protein Binding; Protein Conformation; Protein Folding; Protein Structure, Quaternary; Thermodynamics; Tumor Suppressor Protein p53

Dementia with Lewy Bodies (DLB) can be difficult to distinguish clinically from other dementias.. To investigate the diagnostic utility of CSF alpha-synuclein in differentiating between DLB and other dementias.. Electronic databases were systematically searched for studies investigating reproducible alpha synuclein quantification methods. Random effects model was used to calculate weighted mean difference (WMD) and 95% confidence intervals between DLB and other groups.. A total of 13 studies, comprising 2728 patients were included. Mean CSF alpha-synuclein concentration was significantly lower in DLB patients compared to those with Alzheimers disease (AD) [WMD -0.24; 95% CI, -0.45, -0.03; p = 0.02]. No significant difference was found between patients with DLB compared to Parkinsons disease [WMD 0.05; 95% CI, -0.17, 0.28; p = 0.65] or other neurodegenerative conditions.. CSF alpha synuclein may be of diagnostic use in differentiating between DLB and AD. We propose several recommendations to guide better design of future studies.

Topics: Adult; Age of Onset; Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Data Interpretation, Statistical; Female; Humans; Lewy Body Disease; Male; Middle Aged; Neurodegenerative Diseases; Neuropsychological Tests; Publication Bias; Reproducibility of Results; Research Design; Young Adult

Parkinson disease (PD) is the second most prevalent neurodegenerative disorder after Alzheimer's disease (AD). The formation of the cytoplasmic inclusions named "Lewy bodies" in the brain, considered to be a marker for neuronal degeneration in PD and dementia with Lewy bodies. However, Lewy bodies (LBs) are also observed in approximately 60 percent of both sporadic and familial cases with AD. LBs consist of fibrils mainly formed by post-translational modified α-synuclein (α-syn) protein. The modifications can be truncation, phosphorylation, nitration and mono-, di-, or tri-ubiquitination. Development of disease seems to be linked to events that increase the concentration of α-syn or cause its chemical modification, either of which can accelerate α-syn aggregation. Examples of such events include increased copy number of genes, decreased rate of degradation via the proteasome or other proteases, or modified forms of α-syn. As the aggregation of α-syn in the brain has been strongly implicated as a critical step in the development of several neurodegenerative diseases, the current search for disease-modifying drugs is focused on modification of the process of α-syn deposition in the brain. Recently researchers have screened and designed various molecules that are selectively focused on inhibiting or preventing α-syn aggregation and toxicity. Another strategy that has emerged is to target α-syn expression as a potential therapy for neurodegenerative diseases associated with LBs.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease

The disappointments of a series of large anti-amyloid trials have brought home the point that until the driving force behind Alzheimer's disease, and the way it causes harm, are firmly established and accepted, researchers will remain ill-equipped to find a way to treat patients successfully. The origin of inflammation in neurodegenerative diseases is still an open question. We champion and expand the argument that a shift in intracellular location of α-synuclein, thereby moving a key methylation enzyme from the nucleus, provides global hypomethylation of patients' cerebral DNA that, through being sensed by TLR9, initiates production of the cytokines that drive these cerebral inflammatory states. After providing a background on the relevant inflammatory cytokines, this commentary then discusses many of the known alternatives to the primary amyloid argument of the pathogenesis of Alzheimer's disease, and the treatment approaches they provide. A key point to appreciate is the weight of evidence that inflammatory cytokines, largely through increasing insulin resistance and thereby reducing the strength of the ubiquitously important signaling mediated by insulin, bring together most of these treatments under development for neurodegenerative disease under the one roof. Moreover, the principles involved apply to a wide range of inflammatory diseases on both sides of the blood brain barrier.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Cytokines; DNA Methylation; Epigenesis, Genetic; Humans; Inflammation; Influenza, Human; Insulin Resistance; Lead; Mice; Neurodegenerative Diseases; Parkinson Disease; RNA, Untranslated; Toll-Like Receptor 9

The development of novel therapies against neurodegenerative disorders requires the ability to detect their early, presymptomatic manifestations in order to enable treatment before irreversible cellular damage occurs. Precocious signs indicative of neurodegeneration include characteristic changes in certain protein levels, which can be used as diagnostic biomarkers when they can be detected in fluids such as blood plasma or cerebrospinal fluid. In the case of synucleinopathies, cerebrospinal alpha-synuclein (α-syn) has attracted great interest as a potential biomarker; however, there is ongoing debate regarding the association between cerebrospinal α-syn levels and neurodegeneration in Parkinson disease and synucleinopathies. Post-translational modifications (PTMs) have emerged as important determinants of α-syn's physiological and pathological functions. Several PTMs are enriched within Lewy bodies and exist at higher levels in α-synucleinopathy brains, suggesting that certain modified forms of α-syn might be more relevant biomarkers than the total α-syn levels. However, the quantification of PTMs in bodily fluids poses several challenges. This review describes the limitations of current immunoassay-based α-syn quantification methods and highlights how these limitations can be overcome using novel mass-spectrometry-based assays. In addition, we describe how advances in chemical synthesis, which have enabled the preparation of α-syn proteins that are site-specifically modified at single or multiple residues, can facilitate the development of more accurate assays for detecting and quantifying α-syn PTMs in health and disease.

Topics: alpha-Synuclein; Antibodies, Monoclonal; Biomarkers; Chromatography, Liquid; Humans; Lewy Bodies; Mass Spectrometry; Neurodegenerative Diseases; Parkinson Disease; Peptide Fragments; Peptide Mapping; Phosphorylation; Protein Processing, Post-Translational; Proteolysis; Ubiquitination

For several decades scientists have speculated that the key to understanding age-related neurodegenerative disorders may be found in the unusual biology of the prion diseases. Recently, owing largely to the advent of new disease models, this hypothesis has gained experimental momentum. In a remarkable variety of diseases, specific proteins have been found to misfold and aggregate into seeds that structurally corrupt like proteins, causing them to aggregate and form pathogenic assemblies ranging from small oligomers to large masses of amyloid. Proteinaceous seeds can therefore serve as self-propagating agents for the instigation and progression of disease. Alzheimer's disease and other cerebral proteopathies seem to arise from the de novo misfolding and sustained corruption of endogenous proteins, whereas prion diseases can also be infectious in origin. However, the outcome in all cases is the functional compromise of the nervous system, because the aggregated proteins gain a toxic function and/or lose their normal function. As a unifying pathogenic principle, the prion paradigm suggests broadly relevant therapeutic directions for a large class of currently intractable diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Animals; Humans; Neurodegenerative Diseases; Prion Diseases; Prions; tau Proteins

Pathological aggregation of alpha-synuclein as Lewy-bodies and neurites is a hallmark of a group of neurodegenerative disorders named alpha-synucleinopathies. It is becoming apparent that alpha-synuclein facilitates presynaptic neuronal function in the brain, and events leading to its aggregation produce marked disruption of neurotransmitter release mechanism. We discuss here the literature related to the function of alpha-synuclein at the neuronal synapse in synucleinopathies brains and corresponding animal models.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Synapses

Accumulation of misfolded proteins has been implicated in a variety of neurodegenerative diseases including prion diseases, Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). In the past decade, single-chain fragment variable (scFv) -based immunotherapies have been developed to target abnormal proteins or various forms of protein aggregates including Aβ, SNCA, Htt, and PrP proteins. The scFvs are produced by fusing the variable regions of the antibody heavy and light chains, creating a much smaller protein with unaltered specificity. Because of its small size and relative ease of production, scFvs are promising diagnostic and therapeutic reagents for protein misfolded diseases. Studies have demonstrated the efficacy and safety of scFvs in preventing amyloid protein aggregation in preclinical models. Herein, we discuss recent developments of these immunotherapeutics. We review efforts of our group and others using scFv in neurodegenerative disease models. We illustrate the advantages of scFvs, including engineering to enhance misfolded conformer specificity and subcellular targeting to optimize therapeutic action.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Huntingtin Protein; Immunization, Passive; Nerve Tissue Proteins; Neurodegenerative Diseases; Prions; Single-Chain Antibodies

Prion diseases and prion-like protein misfolding diseases are related to the accumulation of abnormal aggregates of the normal host proteins including prion proteins and Tau protein. These proteins possess self-templating and transmissible characteristics. The crowded physiological environments where the aggregation of these amyloidogenic proteins takes place can be imitated in vitro by the addition of macromolecular crowding agents such as inert polysaccharides. In this review, we summarize the aggregation of prion proteins in crowded physiological environments and discuss the role of macromolecular crowding in prion protein aggregation. We also summarize the aggregation of prion-like proteins including human Tau protein, human α-synuclein, and human copper, zinc superoxide dismutase under macromolecular crowding environments and discuss the role of macromolecular crowding in prion-like protein aggregation. The excluded-volume effects caused by macromolecular crowding could accelerate the aggregation of neurodegenerative disease-associated proteins while inhibiting the aggregation of the proteins that are not neurodegenerative disease-associated.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Prions; tau Proteins

Changes in protein metabolism are key to disease onset and progression in many neurodegenerative diseases. As a prime example, in Parkinson's disease, folding, post-translational modification and recycling of the synaptic protein α-synuclein are clearly altered, leading to a progressive accumulation of pathogenic protein species and the formation of intracellular inclusion bodies. Altered protein folding is one of the first steps of an increasingly understood cascade in which α-synuclein forms complex oligomers and finally distinct protein aggregates, termed Lewy bodies and Lewy neurites. In neurons, an elaborated network of chaperone and co-chaperone proteins is instrumental in mediating protein folding and re-folding. In addition to their direct influence on client proteins, chaperones interact with protein degradation pathways such as the ubiquitin-proteasome-system or autophagy in order to ensure the effective removal of irreversibly misfolded and potentially pathogenic proteins. Because of the vital role of proper protein folding for protein homeostasis, a growing number of studies have evaluated the contribution of chaperone proteins to neurodegeneration. We herein review our current understanding of the involvement of chaperones, co-chaperones and chaperone-mediated autophagy in synucleinopathies with a focus on the Hsp90 and Hsp70 chaperone system. We discuss genetic and pathological studies in Parkinson's disease as well as experimental studies in models of synucleinopathies that explore molecular chaperones and protein degradation pathways as a novel therapeutic target. To this end, we examine the capacity of chaperones to prevent or modulate neurodegeneration and summarize the current progress in models of Parkinson's disease and related neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Humans; Molecular Chaperones; Neurodegenerative Diseases; Parkinson Disease; Protein Folding

The histopathological hallmark of Parkinson's disease (PD) is the presence of fibrillar aggregates referred to as Lewy bodies (LBs), in which α-synuclein is a major constituent. Pale bodies, the precursors of LBs, may serve the material for that LBs continue to expand. LBs consist of a heterogeneous mixture of more than 90 molecules, including PD-linked gene products (α-synuclein, DJ-1, LRRK2, parkin, and PINK-1), mitochondria-related proteins, and molecules implicated in the ubiquitin-proteasome system, autophagy, and aggresome formation. LB formation has been considered to be a marker for neuronal degeneration because neuronal loss is found in the predilection sites for LBs. However, recent studies have indicated that nonfibrillar α-synuclein is cytotoxic and that fibrillar aggregates of α-synuclein (LBs and pale bodies) may represent a cytoprotective mechanism in PD.

Topics: alpha-Synuclein; Animals; Humans; Lewy Bodies; Lewy Body Disease; Neurodegenerative Diseases; Parkinson Disease

Cardiovascular autonomic failure is the second most common dysautonomic feature of α-synucleinopathies and has significant impact on daily activities and quality of life. Here we provide a systematic review of cardiovascular autonomic failure in α-synucleinopathies, emphasizing its impact on cognitive functions and disease outcomes. Articles spanning the period between January 1985 and April 2012 were identified from the PubMed database using a keyword-based search. Epidemiological studies highlight the negative prognostic effect of cardiovascular autonomic failure on cardiovascular and cerebrovascular outcomes and overall mortality in all α-synucleinopathies. Altered cerebral perfusion, vascular pressure stress, and related disruption of the blood-brain barrier may also contribute to the white matter hyperintensities and cognitive dysfunction frequently found in patients affected by neurocardiovascular instability. These findings support the hypothesis that cardiovascular autonomic failure may play a negative prognostic role in α-synucleinopathies and suggest that precocious screening and therapeutic management of cardiovascular autonomic failure may positively impact disease course.

Topics: alpha-Synuclein; Brain; Cardiovascular System; Cognition Disorders; Disease Progression; Fatigue; Humans; Hypotension, Orthostatic; Lewy Body Disease; Multiple System Atrophy; Neurodegenerative Diseases; Parkinson Disease; Primary Dysautonomias; Prognosis; Pure Autonomic Failure

Parkinson's disease (PD) is a devastating neurological condition that affects about 1 % of people older than 65 years of age. In PD, dopaminergic neurons in the mid-brain slowly accumulate cytoplasmic inclusions (Lewy bodies, LBs) of the protein alpha-synuclein (α-syn) and then gradually lose function and die off. Cell death is thought to be causally linked to the aggregation/fibrillization of α-syn. This review focuses on new findings about the structure of α-syn, about how α-syn cooperates with Hsp70 and Hsp40 chaperones to promote neurotransmitter release, and about cell-to-cell transfer of pathogenic forms of α-syn and how Hsp70 might protect against this disease process.

Topics: alpha-Synuclein; Animals; Cell Communication; Cell Death; Humans; Molecular Chaperones; Neurodegenerative Diseases; Neurotransmitter Agents

Lewy body diseases include Parkinson disease and dementia with Lewy bodies and are characterized by the widespread distribution of Lewy bodies in virtually every brain area. The main component of Lewy bodies is alpha-synuclein (AS). Accumulating evidence suggests that AS oligomerization and aggregation are strongly associated with the pathogenesis of Lewy body diseases. AS is a small soluble protein with aggregation-prone properties under certain conditions. These properties are enhanced by posttranslational modifications such as phosphorylation, ubiquitination, nitration, and truncation. Accordingly, Lewy bodies contain abundant phosphorylated, nitrated, and monoubiquitinated AS. However, alternative splicing of the AS gene is also known to modify AS aggregation propensities. Splicing gives rise to four related forms of the protein, the main transcript and those that lack exon 4, exon 6, or both. Since AS structure and properties have been extensively studied, it is possible to predict the consequences of the splicing out of the two aforesaid exons. The present review discusses the latest insights on the mechanisms of AS posttranslational modifications and intends to depict their role in the pathogenesis of Lewy body diseases. The implications of deregulated alternative splicing are examined as well, and a hypothesis for the development of the pure form of dementia with Lewy bodies is proposed.

Topics: alpha-Synuclein; Alternative Splicing; Amino Acid Sequence; Animals; Humans; Lewy Bodies; Lewy Body Disease; Molecular Sequence Data; Neurodegenerative Diseases; Protein Processing, Post-Translational

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Gene Targeting; Humans; Molecular Sequence Data; Neurodegenerative Diseases; Neuronal Plasticity; Protein Conformation; Protein Unfolding

α-Synuclein (AS)-positive inclusions are the pathological hallmark of Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), all belonging to the category of α-synucleinopathies. α-Synucleinopathies represent progressive neurodegenerative disorders characterised by increasing incidences in the population over the age of 65. The relevance of glial reactivity and dysfunction in α-synucleinopathies is highlighted by numerous experimental evidences. Glial AS inclusion pathology is prominent in oligodendroglia of MSA (glial cytoplasmic inclusions) and is a common finding in astroglial cells of PD and DLB, resulting in specific dysfunctional responses. Involvement of AS-dependent astroglial and microglial activation in neurodegenerative mechanisms, and therefore in disease initiation and progression, has been suggested. The aim of this review is to summarise and discuss the multifaceted responses of glial cells in α-synucleinopathies. The beneficial, as well as detrimental, effects of glial cells on neuronal viability are taken into consideration to draw an integrated picture of glial roles in α-synucleinopathies. Furthermore, an overview on therapeutic approaches outlines the difficulties of translating promising experimental studies into successful clinical trials targeting candidate glial pathomechanisms.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Neuroglia; Neurons; Oligodendroglia

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

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

Neurodegenerative diseases are capturing the world's attention as being the next set of diseases we must tackle collectively. Not only are the patients experiencing gradual cognitive and physical decline in most cases, but these diseases are fatal with no prevention currently available. As these diseases are progressive, providing care and symptom treatment for the ageing population is becoming both a medical and a financial challenge. This review discusses how Werner coordination chemistry plays a role in three diseases - those of Alzheimer's, Parkinson's, and prions. Metal ions are considered to be involved in these diseases in part via their propensity to cause toxic aggregation of proteins. First, the coordination of metal ions, with emphasis on copper(II), to metalloproteins that are hallmarks of these diseases - amyloid β, α-synuclein, and prion, respectively - will be discussed. We will present the current understanding of the metal coordination environments created by the amino acids of these proteins, as well as metal binding affinity. Second, a diverse set of examples of rationally designed metal chelators to outcompete this deleterious binding will be examined based on coordination mode and affinity toward bio-relevant metal ions. Overall, this review will give a general overview of protein and metal chelator coordination environments in neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Chelating Agents; Coordination Complexes; Copper; Humans; Neurodegenerative Diseases

Disorders characterized by α-synuclein (α-syn) accumulation, Lewy body formation and parkinsonism (and in some cases dementia) are collectively known as Lewy body diseases. The molecular mechanism (or mechanisms) through which α-syn abnormally accumulates and contributes to neurodegeneration in these disorders remains unknown. Here, we provide an overview of current knowledge and prevailing hypotheses regarding the conformational, oligomerization and aggregation states of α-syn and their role in regulating α-syn function in health and disease. Understanding the nature of the various α-syn structures, how they are formed and their relative contributions to α-syn-mediated toxicity may inform future studies aiming to develop therapeutic prevention and intervention.

Topics: alpha-Synuclein; Animals; Humans; Models, Biological; Neurodegenerative Diseases; Protein Conformation

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

Immunotherapy is currently being intensively explored as much-needed disease-modifying treatment for neurodegenerative diseases. While Alzheimer's disease (AD) has been the focus of numerous immunotherapeutic studies, less attention has been paid to Parkinson's disease (PD) and other neurodegenerative disorders. The reason for this difference is that the amyloid beta (Aβ) protein in AD is a secreted molecule that circulates in the blood and is readably recognized by antibodies. In contrast, α-synuclein (α-syn), tau, huntingtin and other proteins involved in neurodegenerative diseases have been considered to be exclusively of intracellular nature. However, the recent discovery that toxic oligomeric versions of α-syn and tau accumulate in the membrane and can be excreted to the extracellular environment has provided a rationale for the development of immunotherapeutic approaches for PD, dementia with Lewy bodies, frontotemporal dementia, and other neurodegenerative disorders characterized by the abnormal accumulation of these proteins. Active immunization, passive immunization, and T cell-mediated cellular immunotherapeutic approaches have been developed targeting Aβ, α-syn and tau. Most advanced studies, including results from phase III clinical trials for passive immunization in AD, have been recently reported. Results suggest that immunotherapy might be a promising therapeutic approach for neurodegenerative diseases that progress with the accumulation and propagation of toxic protein aggregates. In this manuscript we provide an overview on immunotherapeutic advances for neurodegenerative disorders, with special emphasis on α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Humans; Immunotherapy; Neurodegenerative Diseases

The misfolding and progressive aggregation of specific proteins in selective regions of the nervous system is a seminal occurrence in many neurodegenerative disorders, and the interaction between pathological/toxic proteins to cause neurodegeneration is a hot topic of current neuroscience research. Despite clinical, genetic and experimental differences, increasing evidence indicates considerable overlap between synucleinopathies, tauopathies and other protein-misfolding diseases. Inclusions, often characteristic hallmarks of these disorders, suggest interactions of pathological proteins enganging common downstream pathways. Novel findings that have shifted our understanding in the role of pathologic proteins in the pathogenesis of Alzheimer, Parkinson, Huntington and prion diseases, have confirmed correlations/overlaps between these and other neurodegenerative disorders. Emerging evidence, in addition to synergistic effects of tau protein, amyloid-β, α-synuclein and other pathologic proteins, suggests that prion-like induction and spreading, involving secreted proteins, are major pathogenic mechanisms in various neurodegenerative diseases, depending on genetic backgrounds and environmental factors. The elucidation of the basic molecular mechanisms underlying the interaction and spreading of pathogenic proteins, suggesting a dualism or triad of neurodegeneration in protein-misfolding disorders, is a major challenge for modern neuroscience, to provide a deeper insight into their pathogenesis as a basis of effective diagnosis and treatment.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Humans; Neurodegenerative Diseases; Prion Diseases; Proteostasis Deficiencies; tau Proteins

The neurodegenerative diseases described in this volume, as well as many nonneurodegenerative diseases, are characterized by deposits known as amyloid. Amyloid has long been associated with these various diseases as a pathological marker and has been implicated directly in the molecular pathogenesis of disease. However, increasing evidence suggests that these proteinaceous Congo red staining deposits may not be toxic or destructive of tissue. Recent studies strongly implicate smaller aggregates of amyloid proteins as the toxic species underlying these neurodegenerative diseases. Despite the outward obvious differences among these clinical syndromes, there are some striking similarities in their molecular pathologies. These include dysregulation of intracellular calcium levels, impairment of mitochondrial function, and the ability of virtually all amyloid peptides to form ion-permeable pores in lipid membranes. Pore formation is enhanced by environmental factors that promote protein aggregation and is inhibited by agents, such as Congo red, which prevent aggregation. Remarkably, the pores formed by a variety of amyloid peptides from neurodegenerative and other diseases share a common set of physiologic properties. These include irreversible insertion of the pores in lipid membranes, formation of heterodisperse pore sizes, inhibition by Congo red of pore formation, blockade of pores by zinc, and a relative lack of ion selectivity and voltage dependence. Although there exists some information about the physical structure of these pores, molecular modeling suggests that 4-6-mer amyloid subunits may assemble into 24-mer pore-forming aggregates. The molecular structure of these pores may resemble the β-barrel structure of the toxics pore formed by bacterial toxins, such as staphylococcal α-hemolysin, anthrax toxin, and Clostridium perfringolysin.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Cell Membrane; Humans; Huntington Disease; Mice; Mitochondrial Membranes; Models, Neurological; Neurodegenerative Diseases; Neurons; Prions; Protein Conformation

The accumulation of misfolded proteins is a common feature of many neurodegenerative diseases. These observations suggest a potential link between these disorders and protein quality control, a collection of cellular pathways that sense damage to proteins and facilitate their turnover. Consistent with this idea, activation of quality control components, such as molecular chaperones, has been shown to be protective in multiple neurodegenerative disease models. In addition, key studies have suggested that quality control deteriorates with age, further supporting a relationship between these processes. In this chapter, we discuss the evidence linking neurodegeneration to quality control and present the emerging models. We also speculate on why proper quality control is so difficult for certain proteins.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Autophagy; Heat-Shock Response; Humans; Lysosomes; Mice; Molecular Chaperones; Nerve Tissue Proteins; Neurodegenerative Diseases; Peptides; Prions; Proteasome Endopeptidase Complex; tau Proteins; Translational Research, Biomedical; Ubiquitin; Unfolded Protein Response

Protein misfolding is common to most neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. Recent work using animal models with intracellular α-synuclein and tau inclusions adds decisively to a growing body of evidence that misfolded protein aggregates can induce a self-perpetuating process that leads to amplification and spreading of pathological protein assemblies. When coupled with the progressive nature of neurodegeneration, recognition of such cell-to-cell aggregate spread suggests a unifying mechanism underlying the pathogenesis of these disorders.

Topics: alpha-Synuclein; Animals; Humans; Mice; Neurodegenerative Diseases; Neurofibrillary Tangles; Prions; Proteostasis Deficiencies; tau Proteins

Cytoskeletal polymers play pleiotropic roles in neuroglial morphogenesis, intracellular transport, organization of pre- and post-synaptic scaffolds, etc. Thus, neuroglial dysfunction and degeneration are often accompanied by abnormalities in microtubules, actin and/or intermediate filament systems. Although our understanding of an unconventional cytoskeletal system composed of the septin family of GTP-binding proteins is far behind, recent studies have been revealing that qualitative and/or quantitative abnormalities of septins are also associated with neurodegenerative disorders including hereditary neuralgic amyotrophy, Parkinson disease, schizophrenia and bipolar disorder. A better understanding of the physiological and pathophysiological roles of the septin system should help develop useful biomarkers and therapeutic strategies for these diseases.

Topics: alpha-Synuclein; Animals; Dopamine; Dopamine Plasma Membrane Transport Proteins; Humans; Mice; Neurodegenerative Diseases; Parkinson Disease; Septins; Synaptic Transmission

 All neurodegenerative diseases are related to pathology and accumulation of proteins. Proteins are basic structural and functional components of each cell and their functions are associated with their amino acid composition and spatial structure. The proper functioning of protein is necessary for the proper operation of the body system. In the case of disorders of proteins' spatial structure, the development of pathological processes may occur. Accumulation of abnormal proteins is toxic to nerve cells and causes neurodegeneration. Different disorders are characterized by abnormalities of various proteins. This type of neurodegenerative diseases includes Parkinson's disease, tauopathies, Alzheimer's disease, and prion diseases. Parkinson's disease is characterized by toxicity of α-synuclein. The pathology of tau protein is specific for tauopathies, prion protein for prion diseases. In the case of Alzheimer's disease it is β-amyloid. All proteins responsible for the pathology are present in the physiological state in the organism. Damage to the area of the brain covered by the pathological process and the clinical symptoms are characteristic for a particular type of disease. Detailed knowledge of the mechanisms of the disease can be an important element in the development of effective ways of treatment.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Brain; Humans; Molecular Structure; Neurodegenerative Diseases; Neurons; Parkinson Disease; Prion Diseases; Prions; Synaptic Transmission; tau Proteins; Tauopathies

Protein misfolding, aggregation and deposition are common disease mechanisms in many neurodegenerative diseases including Parkinson's disease (PD). Accumulation of damaged or abnormally modified proteins may lead to perturbed cellular function and eventually to cell death. Thus, neurons rely on elaborated pathways of protein quality control and removal to maintain intracellular protein homeostasis. Molecular chaperones, the ubiquitin-proteasome system (UPS) and the autophagy-lysosomal pathway (ALP) are critical pathways that mediate the refolding or removal of abnormal proteins. The successive failure of these protein degradation pathways, as a cause or consequence of early pathological alterations in vulnerable neurons at risk, may present a key step in the pathological cascade that leads to spreading neurodegeneration. A growing number of studies in disease models and patients have implicated dysfunction of the UPS and ALP in the pathogenesis of Parkinson's disease and related disorders. Deciphering the exact mechanism by which the different proteolytic systems contribute to the elimination of pathogenic proteins, like α-synuclein, is therefore of paramount importance. We herein review the role of protein degradation pathways in Parkinson's disease and elaborate on the different contributions of the UPS and the ALP to the clearance of altered proteins. We examine the interplay between different degradation pathways and provide a model for the role of the UPS and ALP in the evolution and progression of α-synuclein pathology. With regards to exciting recent studies we also discuss the putative potential of using protein degradation pathways as novel therapeutic targets in Parkinson's disease.

Topics: alpha-Synuclein; Autophagy; Humans; Lysosomes; Neurodegenerative Diseases; Neurons; Parkinson Disease; Proteasome Endopeptidase Complex; Proteolysis

Alpha-synuclein (SNCA) gene expression is an important factor in the pathogenesis of Parkinson's disease (PD). Gene multiplication can cause inherited PD, and promoter polymorphisms that increase SNCA expression are associated with sporadic PD. CpG methylation in the promoter region may also influence SNCA expression. By using cultured cells, we identified a region of the SNCA CpG island in which the methylation status altered along with increased SNCA expression. Postmortem brain analysis revealed regional non-specific methylation differences in this CpG region in the anterior cingulate and putamen among controls and PD; however, in the substantia nigra of PD, methylation was significantly decreased. This CpG region may function as an intronic regulatory element for the SNCA gene. Our findings suggest that a novel epigenetic regulatory mechanism controlling SNCA expression influences PD pathogenesis.

Topics: alpha-Synuclein; Animals; CpG Islands; Epigenesis, Genetic; Gene Expression; Genetic Predisposition to Disease; Humans; Neurodegenerative Diseases

Extracellular fibrous amyloid deposits or intracellular inclusion bodies containing abnormal protein aggregates are pathological hallmarks of several neurodegenerative disorders and it has been hotly debated whether these aberrant protein structures merely occur as a consequence of disease or actually participate in a pathogenic cascade which culminates in neural dysfunction and death. Here, we review the role of aberrant protein structure in the two most common neurodegenerative disorders: Alzheimer's disease and Parkinson's disease and in two rare familial dementias, familial British dementia and familial Danish dementia. We also discuss possible mechanisms by which aberrant protein structures may mediate disease and the therapeutic opportunities this knowledge offers.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Humans; Molecular Structure; Neurodegenerative Diseases; Parkinson Disease; Protein Conformation; Protein Folding

This review examines recent studies on the thermodynamics of copper association with amyloid-β, α-synuclein and prion protein, with an eye towards using this information to understand the etiology of associated neurodegenerative diseases. A variety of binding affinities and binding sites, which are essential to understand the function and consequence of copper-protein interaction, have been reported for copper to these three neurobiologic systems. This current review reconciles the disparate models presented in the literature.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Binding Sites; Copper; Humans; Neurodegenerative Diseases; Prions; Protein Binding

Alpha-synuclein (α-syn), a synaptic protein richly expressed in the central nervous system, has been implicated in several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies, which are collectively known as synucleinopathies. By contrast to the clear evidence for the involvement of α-syn in synucleinopathies, its physiological functions remain elusive, which becomes an impediment for revelation of its pathological mechanism. Since α-syn is richly expressed in presynaptic terminals and associated with synaptic vesicles, a large number of studies have been focused on revealing the potential functions of this protein in neurotransmission and synaptic plasticity. In this review article, we summarized recent advances for the role of α-syn in synaptic vesicle recycling, neurotransmitter synthesis and release, and synaptic plasticity. We discussed the possible relevance between the loss of normal α-syn functions in disease conditions and the onset of some neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Neuronal Plasticity; Protein Transport; Synapses; Synaptic Transmission

Prolyl oligopeptidase (PO) interacts with α-syncline in vitro. It is a weak interaction that induces a nucleation prone conformation of α-synuclein. PO accelerates aggregation and fibril formation of α-syncline in a process that can be reversed by specific inhibitors and is also influenced by an impairing mutation in the PO active site. There is evidence that PO and α-synuclein also interact intracellularly, especially in conditions where the expression of α-synuclein is high. Specific PO inhibitors reduce the number of cells with α-synuclein inclusions in a cellular model of Parkinson's disease. If these interactions also exist in the human brain, PO may be a target for the treatment of Parkinson's disease and other synucleinopathies. Whether PO also contributes to the normal physiological functions of α-syncline remains an open question, but there are some intriguing parallels between the proposed functions of both proteins that deserve further investigation.

Topics: alpha-Synuclein; Humans; Molecular Conformation; Molecular Targeted Therapy; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Prolyl Oligopeptidases; Serine Endopeptidases

With the aging population in the Western hemisphere, neurodegenerative parkinsonism and dementia will become two of the great public health challenges of this century. A major pillar in the effort to treat these conditions will be the shift from symptomatic treatment to disease modifying therapy. This step will absolutely require cheap and reliable biomarkers; patients will need to be diagnosed before irreversible change has occurred. α-Synuclein (αS) is a recent candidate biomarker for Lewy body neurodegeneration. It is a 140 amino acid protein that forms the pathological substrate in idiopathic Parkinson's disease (IPD), dementia with Lewy bodies (DLB), as well as multiple system atrophy (MSA), a group of disorders collectively known as the synucleopathies. Biomarker research has investigated αS in blood, skin and cerebrospinal fluid (CSF). Plasma assays have demonstrated inconsistent results but CSF assays show a higher degree of uniformity, mostly demonstrating lower levels of αS in patients with Lewy body disease compared to controls. These results are not yet accurate or reliable enough to use as screening tools or isolated diagnostic tests in established disease. It has become clear that factors other than neurodegeneration affect αS concentrations in these tissue samples, such as genetic and environmental influences. Future studies using standardized techniques and larger patient numbers are awaited to realise the full potential of αS as a more definitive diagnostic biomarker.

Topics: alpha-Synuclein; Biomarkers; Humans; Neurodegenerative Diseases

A number of neurodegenerative diseases, as Parkinson, prion, and Alzheimer's diseases, has been directly associated with altered conformations of certain peptides or proteins that assemble to form highly organized aggregates, also called amyloid fibers. Glycosaminoglycans have shown to play important roles on fibrils formation, stability and resistance to proteolysis. This manuscript reviews from basic concepts on the biochemistry and biology of glycosaminoglycans to their implications in neurodegeneration with particular emphasis in pathologic protein aggregation. Prion protein, Aβ42, Tau, and α-synuclein, are all proteins that can interact with glycosaminoglycans. We document here how these interactions may modify protein conformation, aggregation kinetics, and fibers stabilization with important consequences in disease. We also raise questions which answers may make advance the understanding of the implication of GAGs in neurodegeneration.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Glycosaminoglycans; Humans; Membrane Proteins; Neurodegenerative Diseases; Peptide Fragments; Prion Diseases; Prions; Protein Conformation; Proteins

Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Prion disease, Huntington's disease, and amyotrophic lateral sclerosis are increasingly being realized to have common cellular and molecular mechanisms including protein aggregation and inclusion body formation in selected brain regions. The aggregates usually consist of insoluble fibrillar aggregates containing misfolded protein with β-sheet conformation. The most probable explanation is that inclusions and the aggregates symbolize an end stage of a molecular cascade of several events, and that earlier event in the cascade may be more directly tied up to pathogenesis than the inclusions themselves. Small intermediates termed as 'soluble oligomers' in the aggregation process might influence synaptic dysfunction, whereas large, insoluble deposits might function as reservoir of the bioactive oligomers. Compelling evidence suggests the role of misfolded proteins in the form of oligomers might lead to synaptic dysfunction, neuronal apoptosis and brain damage. However, the mechanism by which oligomers trigger neurodegeneration still remains mysterious. The aim of this article is to review the literature around the molecular mechanism and role of oligomers in neurodegeneration and leading approaches toward rational therapeutics.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Models, Biological; Neurodegenerative Diseases; tau Proteins

The covalent attachment of small ubiquition-like modifier (SUMO) polypeptides, or sumoylation, is an important regulator of the functional properties of many proteins. Among these are many proteins implicated in human diseases including cancer and Huntington's, Alzheimer's, and Parkinson's diseases, as well as spinocerebellar ataxia 1 and amyotrophic lateral sclerosis. The results of two more recent studies identify two additional human disease-associated proteins that are sumoylated, amyloid precursor protein (APP), and lamin A. APP sumoylation modulates Aβ peptide levels, suggesting a potential role in Alzheimer's disease, and decreased lamin A sumoylation due to mutations near its SUMO site has been implicated in causing some forms of familial dilated cardiomyopathy.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Ataxin-1; Ataxins; Disease; Humans; Huntingtin Protein; Intracellular Signaling Peptides and Proteins; Neoplasms; Nerve Tissue Proteins; Neurodegenerative Diseases; Nuclear Proteins; Oncogene Proteins; Protein Deglycase DJ-1; Small Ubiquitin-Related Modifier Proteins; Sumoylation; Superoxide Dismutase; Superoxide Dismutase-1; tau Proteins

Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA) are adult onset neurodegenerative disorders characterised by prominent intracellular α-synuclein aggregates (α-synucleinopathies). The glial contribution to neurodegeneration in α-synucleinopathies was largely underestimated until recently. However, brains of PD and DLB patients exhibit not only neuronal inclusions such as Lewy bodies or Lewy neurites but also glial α-synuclein aggregates. Accumulating experimental evidence in PD models suggests that astrogliosis and microgliosis act as important mediators of neurodegeneration playing a pivotal role in both disease initiation and progression. In MSA, oligodendrocytes are intriguingly affected by aberrant cytoplasmic accumulation of α-synuclein (glial cytoplasmic inclusions, Papp-Lantos bodies). Converging evidence from human postmortem studies and transgenic MSA models suggests that oligodendroglial dysfunction both triggers and exacerbates neuronal degeneration. This review summarises the wide range of responsibilities of astroglia, microglia and oligodendroglia in the healthy brain and the changes in glial function associated with ageing. We then provide a critical analysis of the role of glia in α-synucleinopathies including putative mechanisms promoting a chronically diseased glial microenvironment which can lead to detrimental neuronal changes, including cell loss. Finally, major therapeutic strategies targeting glial pathology in α-synucleinopathies as well as current pitfalls for disease-modification in clinical trials are discussed.

Topics: alpha-Synuclein; Gliosis; Humans; Neurodegenerative Diseases; Neuroglia; Neurons

As populations age, the prevalence of geriatric neurodegenerative diseases will increase. These diseases generally are multifactorial, arising from complex interactions among genes, environment, concurrent morbidities, treatments, and time. This essay provides a concept for the pathogenesis of Lewy body diseases such as Parkinson disease, by considering them in the context of allostasis and allostatic load. Allostasis reflects active, adaptive processes that maintain apparent steady states, via multiple interacting effectors regulated by homeostatic comparators-"homeostats." Stress can be defined as a condition or state in which a sensed discrepancy between afferent information and a setpoint for response leads to activation of effectors, reducing the discrepancy. "Allostatic load" refers to the consequences of sustained or repeated activation of mediators of allostasis. From the analogy of an idling car, the revolutions per minute of the engine can be maintained at any of a variety of levels (allostatic states). Just as allostatic load (cumulative wear and tear) reflects design and manufacturing variations, byproducts of combustion, and time, eventually leading to engine breakdown, allostatic load in catecholaminergic neurons might eventually lead to Lewy body diseases. Central to the argument is that catecholamines in the neuronal cytoplasm are autotoxic and that catecholamines from storage visicles leak into the cytoplasm continuously during life. These neurons therefore depend on vesicular sequestration to limit autotoxicity of cytosolic transmitter. Parkinson disease might be a disease of the elderly because of allostatic load, which depends on genetic predispositions, environmental exposures, repeated stress-related catecholamine release, and time.

Topics: Aged; Allostasis; alpha-Synuclein; Catecholamines; Homeostasis; Humans; Lewy Bodies; Neurodegenerative Diseases; Neurons; Neurotransmitter Agents; Parkinson Disease; Stress, Physiological

Inflammation is secondary to protein accumulation in neurodegenerative diseases, including Alzheimer's, Parkinson's and Amyotrophic Lateral Sclerosis. Emerging evidence indicate sustained inflammatory responses, involving microglia and astrocytes in animal models of neurodegeneration. It is unknown whether inflammation is beneficial or detrimental to disease progression and how inflammatory responses are induced within the CNS. Persistence of an inflammatory stimulus or failure to resolve sustained inflammation can result in pathology, thus, mechanisms that counteract inflammation are indispensable. Here we review studies on inflammation mediated by innate and adaptive immunity in the early stages of neurodegeneration and highlight important areas for future investigation.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Central Nervous System; Humans; Inflammation; Neurodegenerative Diseases; tau Proteins; TNF-Related Apoptosis-Inducing Ligand

Neurodegenerative diseases may extend outside the central nervous system (CNS) and involve the gastrointestinal (GI) tract. The gut would appear to be a pathological marker for neurodegeneration, as well as a site for studying the pathophysiology of neurodegeneration. In fact, both in the ENS and CNS, misfolded proteins are likely to initiate a process of neurodegeneration. For example, the very same protein aggregates can be detected both in the ENS and CNS. In both systems, misfolded proteins are likely to share common cell-to-cell diffusion mechanisms, which may occur through a parallel prion-like diffusion process. Independently from the enteric or central origin, misfolded proteins may proceed along the following steps, they: (i) form aggregates; (ii) are expressed on plasma membrane; (iii) are secreted extracellularly; (iv) are glycated to form advanced glycation end-products (AGEs); (v) are internalized through specific receptors placed on neighboring cells (RAGEs); (vi) are cleared by autophagy; and (vii) are neurotoxic. These features are common for a-synuclein (in Parkinson's disease and other synucleinopathies), β-amyloid and tau (in degenerative dementia), SOD-1 and TDP43 (in amyotrophic lateral sclerosis), and PrPsc (in prion diseases). While in some diseases these features are common to both ENS and CNS, in others this remains a working hypothesis.. This review analyzes GI alterations from a pathological perspective to assess whether the enteric nervous system (ENS) mirrors the neuropathology described in the CNS. We discuss the potential mechanisms that lead to the onset and spread of neurodegeneration within the gut, from the gut to the brain, and vice versa.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Biomarkers; Central Nervous System; Enteric Nervous System; Gastrointestinal Tract; Humans; Neurodegenerative Diseases; Prion Diseases; Prions

Protein aggregation is a common characteristic of many neurodegenerative disorders, and the interaction between pathological/toxic proteins to cause neurodegeneration is a hot topic of current neuroscience research. Despite clinical, genetic, and experimental differences, evidence increasingly indicates considerable overlap between synucleinopathies and tauopathies or other protein-misfolding diseases. Inclusions, characteristics of these disorders, also occurring in other neurodegenerative diseases, suggest interactions of pathological proteins engaging common downstream pathways. Novel findings that have shifted our understanding in the role of pathologic proteins in the pathogenesis of Parkinson and Alzheimer diseases have confirmed correlations/overlaps between these and other neurodegenerative disorders. The synergistic effects of α-synuclein, hyperphosphorylated tau, amyloid-β, and other pathologic proteins, and the underlying molecular pathogenic mechanisms, including induction and spread of protein aggregates, are critically reviewed, suggesting a dualism or triad of neurodegeneration in protein-misfolding disorders, although the etiology of most of these processes is still mysterious.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Neurodegenerative Diseases; Phosphorylation; Protein Binding; tau Proteins

The protein family known as synucleins is composed of α-, β- and γ-synuclein. The most widely studied is the α-synuclein protein due to its participation in essential processes of the central nervous system. Neurotoxicity of this protein is related to the presence of multiplications (duplications and triplications) and point mutations in the gene sequence of the α-synuclein gene (SNCA), differential expression of its isoforms and variations in post-transductional modifications. Neurotoxicity is also related to cytoplasmic inclusions known as Lewy bodies (LBs) and Lewy neurites (LNs), which are also present in α-synucleinopathies. In general, the β-synuclein protein, codified by the SNCB gene, acts as a regulator of processes triggered by α-synuclein and its function is altered by variations in the gene sequence, while γ-synuclein, codified by the SNCG gene, seems to play a major role in certain tumoral processes.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; beta-Synuclein; Humans; Lewy Body Disease; Neurodegenerative Diseases; Parkinson Disease

Many non-infectious neurodegenerative diseases are associated with the accumulation of fibrillar proteins. These diseases all exhibit features that are reminiscent of those of prionopathies, including phenotypic diversity and the propagation of pathology. Furthermore, emerging studies of amyloid-beta, alpha-synuclein and tau--proteins implicated in common neurodegenerative diseases--suggest that they share key biophysical and biochemical characteristics with prions. Propagation of protein misfolding in these diseases may therefore occur through mechanisms similar to those that underlie prion pathogenesis. If this hypothesis is verified in vivo, it will suggest new therapeutic strategies to block propagation of protein misfolding throughout the brain.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Brain; Disease Progression; Humans; Neurodegenerative Diseases; Prions; Protein Conformation; tau Proteins

Neuropathological diagnosis of neurodegenerative dementias evolved by adapting the results of neuroanatomy, biochemistry, and cellular and molecular biology. Milestone findings of intra- and extracellular argyrophilic structures, visualizing protein deposition, initiated a protein-based classification. Widespread application of immunohistochemical and biochemical investigations revealed that (1) there are modifications of proteins intrinsic to disease (species that are phosphorylated, nitrated, oligomers, proteinase-resistant, with or without amyloid characteristics; cleavage products), (2) disease forms characterized by the accumulation of a single protein only are rather the exception than the rule, and (3) some modifications of proteins elude present neuropathological diagnostic procedures. In this review, we summarize how neuropathology, together with biochemistry, contributes to disease typing, by demonstrating a spectrum of disorders characterized by the deposition of various modifications of various proteins in various locations. Neuropathology may help to elucidate how brain pathologies alter the detectability of proteins in body fluids by upregulation of physiological forms or entrapment of different proteins. Modifications of at least the five most relevant proteins (amyloid-beta, prion protein, tau, alpha-synuclein, and TDP-43), aided by analysis of further "attracted" proteins, are pivotal to be evaluated simultaneously with different methods. This should complement the detection of biomarkers associated with pathogenetic processes, and also neuroimaging and genetic analysis, in order to obtain a highly personalized diagnostic profile. Defining clusters of patients based on the patterns of protein deposition and immunohistochemically or biochemically detectable modifications of proteins ("codes") may have higher prognostic predictive value, may be useful for monitoring therapy, and may open new avenues for research on pathogenesis.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Biomarkers; Brain; Dementia; Diagnostic Imaging; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Neurons; Prions; tau Proteins

Alpha-synuclein is a natively unfolded protein associated with a number of neurodegenerative disorders that include Parkinson's disease. In the past, research has focused on the fibrillar form of the protein. Current research now indicates that oligomeric alpha-synuclein is the form of the protein most likely to causes neuronal death. Recent research has suggested that a unique oligomer associated with the copper binding capacity of the protein is the neurotoxic form of the protein. This review looks at the evidence for this possibility.

Topics: alpha-Synuclein; Animals; Copper; Humans; Inclusion Bodies; Iron; Neurodegenerative Diseases; Neurons; Parkinson Disease; Protein Multimerization

Neurodegenerative diseases are more and more prevalent in our aging societies. There is strong evidence that glycogen synthase kinase (GSK)-3b plays a crucial role in Alzheimer's disease (AD). Indeed, it is involved in the regulation of the two major neuropathological hallmarks present in the brains of AD patients. Interestingly, the kinase has been implicated in multiple cellular processes and linked with the pathogenesis and neuronal loss in several neurodegenerative diseases, including Parkinson's and Huntington's diseases, in which abnormally elevated levels of GSK-3b activity have been reported. In this review, we will provide an overview of the current data pointing out the convergent role of GSK-3b in the neuropathological pathways of these diseases. We will also discuss the rationale for the development of specific inhibitors with therapeutic potentials for such devastating human diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Apoptosis; Brain; Carrier Proteins; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Lewy Bodies; Mitochondria; Models, Neurological; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Parkinson Disease; Phosphorylation; Plaque, Amyloid; Presenilins; Protein Kinase Inhibitors; Protein Processing, Post-Translational; tau Proteins

Recent studies that alleles in the hemochromatosis gene may accelerate the onset of Alzheimer's disease by five years have validated interest in the model in which metals (particularly iron) accelerate disease course. Biochemical and biophysical measurements demonstrated the presence of elevated levels of neurotoxic copper zinc and iron in the brains of AD patients. Intracellular levels of APP holoprotein were shown to be modulated by iron by a mechanism that is similar to the translation control of the ferritin L- and H mRNAs by iron-responsive element (IRE) RNA stem loops in their 5' untranslated regions (5'UTRs). More recently a putative IRE-like sequence was hypothesized present in the Parkinsons's alpha synuclein (ASYN) transcript (see [A.L. Friedlich, R.E. Tanzi, J.T. Rogers, The 5'-untranslated region of Parkinson's disease alpha-synuclein messenger RNA contains a predicted iron responsive element, Mol. Psychiatry 12 (2007) 222-223. [6]]). Together with the demonstration of metal dependent translation of APP mRNA, the involvement of metals in the plaque of AD patients and of increased iron in striatal neurons in the substantia nigra (SN) of Parkinson's disease patients have stimulated the development of metal attenuating agents and iron chelators as a major new therapeutic strategy for the treatment of these neurodegenerative diseases. In the case of AD, metal based therapeutics may ultimately prove more cost effective than the use of an amyloid vaccine as the preferred anti-amyloid therapeutic strategy to ameliorate the cognitive decline of AD patients.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Base Sequence; Chelating Agents; Ferritins; Homeostasis; Humans; Inflammation; Iron; Molecular Sequence Data; Neurodegenerative Diseases; Parkinson Disease; Protein Biosynthesis; Receptors, Transferrin; RNA, Messenger; tau Proteins

Intra- and/or extracellular proteinaceous inclusions in the brain tissue are characteristic pathological markers of many neurodegenerative diseases. Tau protein in neurofibrillary tangles and beta-amyloid in senile plaques are associated with Alzheimer's disease. Tau is associated with various neurological conditions, which are collectively referred to as tauopathies. Alpha-synucleinopathy is a term that collectively refers to a set of diseases in which neurodegeneration is accompanied by intracellular accumulation of alpha-synuclein in neurons or glial cells. Recently, TDP-43 has been identified as a major disease protein in the ubiquitinated inclusions in deseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration with tau-negative, ubiquitin-positive inclusions. Thus, these neurodegenerative disorders comprise a new disease class, namely, TDP-43 proteinopathy. In this article, we review the present understanding of histopathological features of basal ganglia lesions in protein conformation disorders, including tauopathy, alpha-synucleinopathy, and TDP-43 proteinopathy.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Basal Ganglia; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; tau Proteins

Multiple system atrophy (MSA) is a rare late onset neurodegenerative disorder which presents with autonomic failure and a complicated motor syndrome including atypical parkinsonism, ataxia and pyramidal signs. MSA is a glial alpha-synucleinopathy with rapid progression and currently poor therapeutic management. This paper reviews the clinical features, natural history and novel diagnostic criteria for MSA as well as contemporary knowledge on pathogenesis based on evidence from neuropathological studies and experimental models. An outline of the rationale for managing symptomatic deterioration in MSA is provided together with a summary of novel experimental therapeutic approaches to decrease disease progression.

Topics: alpha-Synuclein; Animals; Disease Progression; Humans; Multiple System Atrophy; Neurodegenerative Diseases; Shy-Drager Syndrome

Neurodegenerative diseases are characterized by the deposition in a variety of tissues of specific proteins as aggregated species that share a distinctive fibrillar or amorphous structure. Although amyloid inclusions (deposits) are predominantly proteinaceous, careful examination of diseases tissues has revealed the presence of a significant quantity of other species, such as nucleic acids and/or polysaccharide species, associated with the inclusions. Recently, both DNA and RNA have been shown to be able to stimulate formation of fibrillar or amorphous aggregates in vitro by alpha-synuclein, tau protein and prion proteins, and to act as a template for accelerating the aggregation of copper/zinc superoxide dismutase. Although the specificity and nature of interactions between disease-linked proteins and nucleic acids are controversial, the sites of interactions involved should be the positively charged surface motifs on the proteins. This review will mainly highlight the important progress in studies on the nucleic acid-induced structural conversions and aggregation of the proteins linked to neurodegenerative diseases. Thereby, we attempt to understand biological and pathological implications of nucleic acid-induced protein aggregation.

Topics: alpha-Synuclein; Animals; Humans; Microscopy, Electron, Transmission; Models, Molecular; Multiprotein Complexes; Nerve Tissue Proteins; Neurodegenerative Diseases; Nucleic Acids; Prions; Protein Conformation; Superoxide Dismutase

Neurodegenerative diseases constitute a set of pathological conditions originating from the slow, irreversible and systematic cell loss within the various regions of the brain and/or the spinal cord. Neurodegenerative diseases are proteinopathies associated with misbehavior and disarrangement of a specific protein, affecting its processing, functioning, and/or folding. Many proteins associated with human neurodegenerative diseases are intrinsically disordered; i.e., they lack stable tertiary and/or secondary structure under physiological conditions in vitro. Intrinsically disordered proteins (IDPs) have broad presentation in nature. Functionally, they complement ordered proteins, being typically involved in regulation, signaling and control. Structures and functions of IDPs are intensively modulated by alternative splicing and posttranslational modifications. It is recognized now that nanoimaging offers a set of tools to analyze protein misfolding and self-assembly via monitoring the aggregation process, to visualize protein aggregates, and to analyze properties of these aggregates. The major goals of this review are to show the interconnections between intrinsic disorder and human neurodegenerative diseases and to overview a recent progress in development of novel nanoimaging tools to follow protein aggregation.

Topics: alpha-Synuclein; Alzheimer Disease; Amino Acid Sequence; Amyloid; Amyloidosis; Computational Biology; Down Syndrome; Humans; Lewy Body Disease; Models, Molecular; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Prion Diseases; Protein Conformation

When caused by multiplication mutations of its gene, increased expression of alpha-synuclein is associated with familial parkinsonism. Here we discuss the possibility that other mechanisms of alpha-synuclein elevation contribute to the pathogenesis of idiopathic, sporadic Parkinson's disease and other human synucleinopathies. Environmental (e.g. toxic exposures) and genetic (e.g. gene polymorphisms) risk factors, on the background of normal aging, are likely to enhance vulnerability to neurodegenerative processes. Current evidence suggests that an increased level of neuronal alpha-synuclein may represent a key pathogenetic event common to these risk factors. Higher protein expression could underlie a gain of toxic properties of alpha-synuclein (e.g. enhanced tendency to aggregate) that predispose and/or directly contribute to neuronal demise. An important corollary to this latter concept is that a promising therapeutic approach against Parkinson's and other neurodegenerative diseases is to prevent alpha-synuclein accumulation. Means to achieve this include (i) the use of RNA interference to suppress alpha-synuclein expression, (ii) the induction of neuronal pathways of protein degradation (e.g. macroautophagy) involved in alpha-synuclein clearance, and (iii) the development of anti-aggregation agents counteracting the formation of toxic oligomeric or fibrillar forms of the protein.

Topics: Aging; alpha-Synuclein; Animals; Autophagy; Gene Expression Regulation; Genetic Predisposition to Disease; Humans; Models, Biological; Neurodegenerative Diseases; Neurons; Polymorphism, Genetic; Promoter Regions, Genetic; Risk Factors; RNA Interference

The term neurodegenerative disorders, encompasses a variety of underlying conditions, sporadic and/or familial and are characterized by the persistent loss of neuronal subtypes. These disorders can disrupt molecular pathways, synapses, neuronal subpopulations and local circuits in specific brain regions, as well as higher-order neural networks. Abnormal network activities may result in a vicious cycle, further impairing the integrity and functions of neurons and synapses, for example, through aberrant excitation or inhibition. The most common neurodegenerative disorders are Alzheimer's disease, Parkinson's disease, Amyotrophic Lateral Sclerosis and Huntington's disease. The molecular features of these disorders have been extensively researched and various unique neurotherapeutic interventions have been developed. However, there is an enormous coercion to integrate the existing knowledge in order to intensify the reliability with which neurodegenerative disorders can be diagnosed and treated. The objective of this review article is therefore to assimilate these disorders' in terms of their neuropathology, neurogenetics, etiology, trends in pharmacological treatment, clinical management, and the use of innovative neurotherapeutic interventions.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Anticonvulsants; Antipsychotic Agents; Cholinergic Antagonists; Dopamine Agents; Humans; Huntingtin Protein; Huntington Disease; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; tau Proteins

Synucleinopathies are a group of neurodegenerative diseases characterized by accumulation and aggregation of the protein alpha-synuclein in neuronal perikarya and processes. In contrast to the proximal localization of alpha-synuclein in diseased states, under physiologic conditions, the bulk of alpha-synuclein is present in distant presynaptic terminals. Thus, pathologic conditions lead to mislocalization and aggregation of alpha-synuclein in neuronal cell bodies, and an outstanding question relates to the cell-biological mechanisms that can lead to such mislocalization. Like most other synaptic proteins, alpha-synuclein is synthesized in the neuronal perikarya and then transported into axons and synaptic domains. Accordingly, it has been hypothesized that disturbances in biogenesis/axonal transport or presynaptic targeting of alpha-synuclein can lead to its mislocalization in diseased states. In this chapter, key observations that lead to this hypothesis are presented in addition to a review of some recent literature that has directly addressed this issue. Finally, conflicting results that have resulted from such studies are also highlighted, and a view is offered to reconcile these controversies.

Topics: alpha-Synuclein; Animals; Dementia; Humans; Neurodegenerative Diseases

Neurodegenerative brain diseases, including Alzheimer's disease, frontotemporal degeneration and Lewy body disease, are the most frequent pathologies underlying cognitive disorders in old age. This review outlines recent advances in the understanding of key molecular mechanisms involved in these neurodegenerations, particularly with regard to the abnormal processing of proteins. The consequences of these novel insights for therapeutic interventions are also explained.. Aberrant processing, misfolding, and subsequent deposition of amyloid beta protein, TAU, alpha-synuclein, and TDP-43 are key events in the pathological cascades of neurodegenerations leading to cognitive impairment and dementia. The nonpolymerized, oligomeric forms of these proteins have neurotoxic properties including the disruption of synaptic function and the induction of oxidative stress. The aggregation and deposition of these proteins may represent a neuronal repair mechanism which ultimately worsens the deleterious effects of the preaggregated forms. Novel disease-modifying treatment strategies aim at down-regulating protein production, inhibiting polymerization, or removing preaggregated forms of the proteins from the brain.. Recent research has elucidated important molecular events in neurodegenerative diseases upstream of the aggregation and deposition of proteins which forms their histopathological hallmarks. These insights translate into novel therapeutic strategies which are currently evaluated in clinical trials.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Cognition Disorders; DNA-Binding Proteins; Humans; Mice; Neurobiology; Neurodegenerative Diseases; Oxidative Stress; tau Proteins

Neurodegenerative diseases are characterized by selective and progressive loss of specific populations of neurons, which determines the clinical presentation. The same neuronal populations can be affected in a number of different disorders. Given that the clinical presentation reflects the particular population of neurons that are targets of the disease process, it is clear that for any given clinical syndrome, more than one neurodegenerative disease can account for the clinical syndrome. Because of this clinical ambiguity, for the purpose of this brief review neurodegenerative disorders are classified according to the underlying molecular pathology rather than their clinical presentation. The major neurodegenerative diseases can be classified into amyloidoses, tauopathies, alpha-synucleinopathies and TDP-43 proteinopathies.

Topics: alpha-Synuclein; Amyloidosis; Gene Expression; Humans; Neurodegenerative Diseases; Neurons; Pathology, Molecular; Syndrome; Tauopathies; TDP-43 Proteinopathies

A number of neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, involve the formation of protein aggregates. The primary constituent of these aggregates belongs to a unique class of heteropolymers known as intrinsically disordered proteins (IDPs). While many proteins fold to a unique conformation that is determined by their amino acid sequence, IDPs do not adopt a single well-defined conformation in solution. Instead, they populate a heterogeneous set of conformers under physiological conditions. Despite this intrinsic propensity for disorder, a number of these proteins can form ordered aggregates both in vitro and in vivo. As the formation of these aggregates may play an important role in disease pathogenesis, a detailed structural characterization of these proteins and their mechanism of aggregation is of critical importance. However, new methods are needed to understand the diversity of structures that make up the unfolded ensemble of these systems. In this review, we discuss recent advances in the structural analysis and modeling of IDPs involved in neurodegenerative diseases. While there are challenges in both the experimental characterization and the modeling of such proteins, a comprehensive understanding of the structure of IDPs will likely facilitate the development of effective therapies for a number of neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Drug Design; Humans; Models, Molecular; Neurodegenerative Diseases; Protein Unfolding; tau Proteins; Thermodynamics

Parkinson's disease, Alzheimer's disease and other neurodegenerative disorders share a common pathologic pathway with aggregation and deposition of misfolded proteins causing a disruption of particular neuronal networks. Several mechanisms have been implicated in the down-stream events following deposition of misfolded proteins including failure of cellular defenses among many others. Recently, naturally occurring autoantibodies against ss-amyloid and alpha-synuclein have been detected in healthy persons and altered levels in patients were associated with particular neurodegenerative disorders. In this review the current knowledge on the role of naturally occurring autoantibodies is discussed in respect to neurodegenerative disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Autoantibodies; Creutzfeldt-Jakob Syndrome; Humans; Mice; Neurodegenerative Diseases; Parkinson Disease; Prions

Alpha-synuclein is an abundant presynaptic brain protein, misfolding, aggregation and fibrillation of which are implicated as critical factors in several neurodegenerative diseases. The list of the well-known synucleinopathies includes such devastating disorders as Parkinson's disease, Lewy body variant of Alzheimer's disease, diffuse Lewy body disease, dementia with Lewy bodies, multiple system atrophy, and neurodegeneration with brain iron accumulation type I. The precise functions of alpha-synuclein remain elusive, but there are evidence indicating its involvement in regulation vesicular release and/or turnover and synaptic function in the central nervous system. It might play a role in neuronal plasticity responses, bind fatty acids, regulate certain enzymes, transporters, and neurotransmitter vesicles, be involved in neuronal survival and even can act as a molecular chaperone. Structurally, alpha-synuclein is an illustrative member of the rapidly growing family of natively unfolded (or intrinsically disordered) proteins and considerable knowledge has been accumulated about its structural properties and conformational behavior. The molecular mechanisms underlying misfolding, aggregation and fibrillation of alpha-synuclein and the role of various environmental and genetic factors in stimulation and inhibition of these processes are relatively well understood. Here, the main structural features of alpha-synuclein, its functions, and involvement in various human diseases are summarized providing a foundation for better understanding of the biochemistry, biophysics and neuropathology of alpha-synuclein aggregation.

Topics: alpha-Synuclein; Amino Acid Sequence; Amino Acid Substitution; Animals; Humans; Models, Molecular; Molecular Sequence Data; Neurodegenerative Diseases; Point Mutation; Protein Folding; Protein Processing, Post-Translational

Neuropathological investigations have identified major hallmarks of chronic neurodegenerative disease. These include protein aggregates called Lewy bodies in dementia with Lewy bodies and Parkinson's disease. Mutations in the alpha-synuclein gene have been found in familial disease and this has led to intense focused research in vitro and in transgenic animals to mimic and understand Parkinson's disease. A decade of transgenesis has lead to overexpression of wild type and mutated alpha-synuclein, but without faithful reproduction of human neuropathology and movement disorder. In particular, widespread regional neuronal cell death in the substantia nigra associated with human disease has not been described. The intraneuronal protein aggregates (inclusions) in all of the human chronic neurodegenerative diseases contain ubiquitylated proteins. There could be several reasons for the accumulation of ubiquitylated proteins, including malfunction of the ubiquitin proteasome system (UPS). This hypothesis has been genetically tested in mice by conditional deletion of a proteasomal regulatory ATPase gene. The consequences of gene ablation in the forebrain include extensive neuronal death and the production of Lewy-like bodies containing ubiquitylated proteins as in dementia with Lewy bodies. Gene deletion in catecholaminergic neurons, including in the substantia nigra, recapitulates the neuropathology of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Humans; Lewy Bodies; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Ubiquitin

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

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

A number of studies have demonstrated a role for transition metals and oxidative stress in the etiology of Parkinson's disease (PD). Genetic and biochemical evidence also clearly links the protein alpha-synuclein (alphaSyn) to PD and a number of associated diseases. In these "synucleinopathies", alphaSyn is deposited, often in oligomerized forms, as cytoplasmic inclusions known as Lewy bodies and Lewy neurites. alphaSyn cross-linking/oligomerization can occur via a number of processes, most stimulated by metal catalyzed oxidation (MCO). In PD, the increased sensitivity of midbrain neurons expressing high levels of oxidizable catecholamines may provide one clue to account for degeneration of these neurons. In other regions of the nervous system that develop Lewy body pathology, the mode of alphaSyn oligomerization is less clear. Thus, the relationship between alphaSyn and MCO, either direct or indirect, represents a particular concern for possible treatment of these various diseases.

Topics: alpha-Synuclein; Animals; Brain Chemistry; Catalysis; Humans; Lipid Peroxidation; Metals; Neurodegenerative Diseases; Oxidation-Reduction

Although the pathogenetic mechanisms underlying neurodegenerative diseases have been long elusive, recent progress in molecular neurogenetics and neurobiology has suggested that accumulation of misfolded protein leads to dysfunction and degeneration of neurons. Misfolded proteins have propensities to form fibrils termed amyloid fibrils. In the process of amyloid fibrils, intermediate forms such as oligomers and protofibrils are produced and thought to have cytotoxic effects to neurons. Neurotoxicity mediated by misfolded proteins are also caused by stress response such as unfolded protein response. Moreover, recent findings indicate that nonneuronal cells surrounding neurons or extracellular misfolded proteins promote neurodegeneration. To eliminate toxic proteins would constitute promising future therapy for neurodegenerative disorders.

Topics: alpha-Synuclein; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Protein Conformation; Protein Folding; tau Proteins

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

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

The fate of proteins with amyloidogenic properties depends critically on their immediate biochemical environment. However, the role of biological interfaces such as membrane surfaces, as promoters of pathological aggregation of amyloidogenic proteins, is rarely studied and only established for the amyloid-beta protein (A beta) involved in Alzheimer's disease, and alpha-synuclein in Parkinsonism. The occurrence of binding and misfolding of these proteins on membrane surfaces, is poorly understood, not at least due to the two-dimensional character of this event. Clearly, the nature of the folding pathway for A beta protein adsorbed upon two-dimensional aggregation templates, must be fundamentally different from the three-dimensional situation in solution. Here, we summarize the current research and focus on the function of membrane interfaces as aggregation templates for amyloidogenic proteins (and even prionic ones). One major aspect will be the relationship between membrane properties and protein association and the consequences for amyloidogenic products. The other focus will be on a general understanding of protein folding pathways on two-dimensional templates on a molecular level. Finally, we will demonstrate the potential importance of membrane-mediated aggregation for non-amphiphatic soluble amyloidogenic proteins, by using the SOD1 protein involved in the amyotrophic lateral sclerosis syndrome.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Cell Membrane; Dimerization; Humans; Multiprotein Complexes; Neurodegenerative Diseases; Protein Binding; Protein Conformation; Protein Folding; Solubility; Superoxide Dismutase; Superoxide Dismutase-1; Surface Properties

For millennia, humans have harnessed the astonishing power of yeast, producing such culinary masterpieces as bread, beer and wine. Therefore, in this new millennium, is it very farfetched to ask if we can also use yeast to unlock some of the modern day mysteries of human disease? Remarkably, these seemingly simple cells possess most of the same basic cellular machinery as the neurons in the brain. We and others have been using the baker's yeast, Saccharomyces cerevisiae, as a model system to study the mechanisms of devastating neurodegenerative diseases such as Parkinson's, Huntington's, Alzheimer's and amyotrophic lateral sclerosis. While very different in their pathophysiology, they are collectively referred to as protein-misfolding disorders because of the presence of misfolded and aggregated forms of various proteins in the brains of affected individuals. Using yeast genetics and the latest high-throughput screening technologies, we have identified some of the potential causes underpinning these disorders and discovered conserved genes that have proven effective in preventing neuron loss in animal models. Thus, these genes represent new potential drug targets. In this review, I highlight recent work investigating mechanisms of cellular toxicity in a yeast Parkinson's disease model and discuss how similar approaches are being applied to additional neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Beer; Brain; Bread; Gene Expression Regulation; Humans; Neurodegenerative Diseases; Protein Folding; Saccharomyces cerevisiae

The aggregation of proteins has been hypothesized to be an underlying cause of many neurological disorders including Alzheimer's, Parkinson's, and Huntington's diseases; protein aggregation is also important to normal life function in cases such as G to F-actin, glutamate dehydrogenase, and tubulin and flagella formation. For this reason, the underlying mechanism of protein aggregation, and accompanying kinetic models for protein nucleation and growth (growth also being called elongation, polymerization, or fibrillation in the literature), have been investigated for more than 50 years. As a way to concisely present the key prior literature in the protein aggregation area, Table 1 in the main text summarizes 23 papers by 10 groups of authors that provide 5 basic classes of mechanisms for protein aggregation over the period from 1959 to 2007. However, and despite this major prior effort, still lacking are both (i) anything approaching a consensus mechanism (or mechanisms), and (ii) a generally useful, and thus widely used, simplest/"Ockham's razor" kinetic model and associated equations that can be routinely employed to analyze a broader range of protein aggregation kinetic data. Herein we demonstrate that the 1997 Finke-Watzky (F-W) 2-step mechanism of slow continuous nucleation, A --> B (rate constant k1), followed by typically fast, autocatalytic surface growth, A + B --> 2B (rate constant k2), is able to quantitatively account for the kinetic curves from all 14 representative data sets of neurological protein aggregation found by a literature search (the prion literature was largely excluded for the purposes of this study in order provide some limit to the resultant literature that was covered). The F-W model is able to deconvolute the desired nucleation, k1, and growth, k2, rate constants from those 14 data sets obtained by four different physical methods, for three different proteins, and in nine different labs. The fits are generally good, and in many cases excellent, with R2 values >or=0.98 in all cases. As such, this contribution is the current record of the widest set of protein aggregation data best fit by what is also the simplest model offered to date. Also provided is the mathematical connection between the 1997 F-W 2-step mechanism and the 2000 3-step mechanism proposed by Saitô and co-workers. In particular, the kinetic equation for Saitô's 3-step mechanism is shown to be mathematically identical to the earlier, 1997 2-step F-W mechanism und

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Catalysis; Chemical Precipitation; Crystallization; Data Interpretation, Statistical; Humans; Kinetics; Models, Theoretical; Neurodegenerative Diseases; Peptides; Surface Properties

Many neurodegenerative diseases such as Parkinson's, Alzheimer's, Huntington's and Lou Gehrig's disease are associated with the misfolding and aggregation of proteins. While the relevance of these aggregates for neuronal degeneration and their impact on cellular function is still a matter of debate, several experimental therapeutic approaches have been aimed at interfering with protein aggregation. In this review, we want to summarize the current understanding of aggregate formation and toxicity in neurodegenerative diseases with an emphasis on Parkinson's disease. Furthermore, we will discuss current treatment strategies in these diseases targeting aggregate formation and concurrent neuronal cell death in these diseases.

Topics: alpha-Synuclein; Humans; Lewy Bodies; Molecular Chaperones; Neurodegenerative Diseases; Neurons; Parkinson Disease; Proteasome Endopeptidase Complex; Protein Folding; Protein Processing, Post-Translational; Proteins; Ubiquitin; Ubiquitin-Protein Ligases

Alpha-synuclein (AS) is the main constituent of Lewy bodies. There is an ongoing discussion if overexpression is already dangerous, or if toxicity is subjected to oligomers, protofibrils or mature aggregates. The facts that the central hydrophobic part of AS is also a constituent of amyloid plaques in Alzheimer's disease (AD) and that a majority of patients have Lewy bodies and Lewy neurites in specific brain areas raised our interest in the contribution of AS to AD pathogenesis. The N-terminal amino acid sequence 1-15 of beta-synuclein (BS) seems to be a natural antiaggregation factor for AS. We synthesized a library with different sequence variations. Several of these peptides displayed neuroprotective activity in tissue culture models of neurodegeneration induced by oxidative stress or beta-amyloid 1-42. In spite of the fact that these peptides have a short half-life, a significant in vivo reduction in brain plaque load and improvement of behavior was demonstrated in amyloid precursor protein transgenic mice after intranasal treatment for 2 months. KEGV, the shortest sequence, was also active after intraperitoneal application. The in vitro effects cannot be explained by the antiaggregatory potential, but most likely by interaction of BS derivates with antiapoptotic PI3/Akt or antioxidative pathways. The possibility that BS-derived peptidomimetics act as neuroprotectants and prevent protein misfolding suggests therapeutic usefulness.

Topics: alpha-Synuclein; Animals; Drug Delivery Systems; Humans; Neurodegenerative Diseases; Neuropeptides

Abnormal protein aggregates, in the form of either extracellular plaques or intracellular inclusions, are an important pathological feature of the majority of neurodegenerative disorders. The major molecular constituents of these lesions, viz., beta-amyloid (Abeta), tau, and alpha-synuclein, have played a defining role in the diagnosis and classification of disease and in studies of pathogenesis. The molecular composition of a protein aggregate, however, is often complex and could be the direct or indirect consequence of a pathogenic gene mutation, be the result of cell degeneration, or reflect the acquisition of new substances by diffusion and molecular binding to existing proteins. This review examines the molecular composition of the major protein aggregates found in the neurodegenerative diseases including the Abeta and prion protein (PrP) plaques found in Alzheimer's disease (AD) and prion disease, respectively, and the cellular inclusions found in the tauopathies and synucleinopathies. The data suggest that the molecular constituents of a protein aggregate do not directly cause cell death but are largely the consequence of cell degeneration or are acquired during the disease process. These findings are discussed in relation to diagnosis and to studies of to disease pathogenesis.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Inclusion Bodies; Neurodegenerative Diseases; Plaque, Amyloid; PrPC Proteins; PrPSc Proteins; tau Proteins

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

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

Neurodegenerative disorders include a variety of pathological conditions, which share similar critical metabolic processes such as protein aggregation and oxidative stress, both of which are associated with the involvement of metal ions. In this review Alzheimer's disease and Parkinson's disease are mainly discussed, with the aim of identifying common trends underlying these neurological conditions. Chelation therapy could be a valuable therapeutic approach, since metals are considered to be a pharmacological target for the rationale design of new therapeutic agents directed towards the treatment of neurodegeneration.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Ions; Iron Chelating Agents; Metals; Molecular Structure; Neurodegenerative Diseases; Oxidation-Reduction; Oxidative Stress; Prions

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

Pathological studies have prompted the idea that Parkinson disease (PD) is a multisystem disorder, which starts far away from the nigrostriatal dopamine system and it goes through a long pre-clinical period. Evidence from epidemiological research, functional imaging, olfaction and sleep studies provides support to this hypothesis. Accordingly, PD is seen as an homogeneous disease which sequentially affects different neural structures leading to a well-defined clinical picture. This concept, recently named PD complex, has deep theoretical and practical implications which raise some concerns. This report shows the concept of classical PD as opposed to PD complex. Although the relevance of the central argument concerning the PD complex concept is admitted, it needs to be fully proved before premature conclusions are drawn. In contrast, the notion of classical and clinically significant PD can explain many of the well-characterized pathological and clinical features of the disease and it gives support to the idea that the magic word in PD is variability.

Topics: Aged; alpha-Synuclein; Brain; Brain Chemistry; Cell Death; Cerebral Cortex; Corpus Striatum; Disease Progression; Dopamine; Enteric Nervous System; Humans; Lewy Bodies; Lewy Body Disease; Male; Medulla Oblongata; Models, Neurological; Neurodegenerative Diseases; Olfaction Disorders; Parkinson Disease; Proteasome Endopeptidase Complex; REM Sleep Behavior Disorder; Risk; Substantia Nigra; Ubiquitin; Vagus Nerve

Aggregation of alpha-synuclein, an abundant and conserved pre-synaptic brain protein, is implicated as a critical factor in several neurodegenerative diseases. These diseases, known as synucleinopathies, include Parkinson's disease, dementia with Lewy bodies (LBs), diffuse LB disease, the LB variant of Alzheimer's disease, multiple system atrophy, and neurodegeneration with brain iron accumulation type I. Although the precise nature of in vivoalpha-synuclein function remains elusive, considerable knowledge has been accumulated about its structural properties and conformational behavior. alpha-Synuclein is a typical natively unfolded protein. It is characterized by the lack of rigid, well-defined, 3-D structure and possesses remarkable conformational plasticity. The structure of this protein depends dramatically on its environment and it accommodates a number of unrelated conformations. This paper provides an overview of the biochemistry, biophysics, and neuropathology of alpha-synuclein aggregation.

Topics: alpha-Synuclein; Animals; Cell Death; Humans; Lewy Bodies; Neurodegenerative Diseases; Protein Conformation; Protein Folding

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

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

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Autophagy; Autophagy-Related Protein 12; Autophagy-Related Protein 8 Family; Lewy Bodies; Mice; Microtubule-Associated Proteins; Neurodegenerative Diseases; Organelles; Peptides; Proteins; Saccharomyces cerevisiae Proteins; Starvation; Ubiquitin

Alpha-synuclein is the main constituent of intra-neuronal Lewy bodies, which are characteristic of Parkinson's disease, but aggregates are also found as axonal inclusions. Alpha-synuclein pathology is found together with beta-amyloid plaques and neurofibrillary tangles in Alzheimer's disease and other neurodegenerative disorders. In spite of the fact that the biological function of this synaptic protein is not known so far, there is an increasing body of evidence indicating an interaction with amyloid peptides, but also with tau-hyperphosphorylation. A high proportion of alpha-synuclein purified from Lewy bodies is phosphorylated on Ser129. There are still different opinions about the toxicity of the alpha-synuclein aggregates. Alpha-synuclein seems to influence different intracellular signaling pathways which are in direct relation to defense mechanisms against reactive oxygen species or apoptosis. It is obvious that overproduction of alpha-synuclein, but also different mutations, are inducing the formation of aggregates. Because of the possible link to neurodegeneration, different attempts have been made to counteract alpha-synuclein aggregation. An interesting approach is utilizing beta-synuclein, a biological factor, with an aminoacid sequence closely resembling that of alpha-synuclein. Proof of concept studies indicated that overexpression of beta-synuclein is able to counteract alpha-synuclein aggregation in a transgenic animal model, while also ameliorating functional deficits. As an alternative approach, the use of low molecular beta-synuclein N-terminal peptide derivatives has been considered. Several of these structures displayed clear neuroprotective activities in tissue culture models of neurodegeneration, including beta-amyloid toxicity. Therefore it has been speculated that these compounds might have a broad therapeutic efficacy in different neurodegenerative disorders. A proof of concept study in hAPP-transgenic animals resulted in a highly significant decrease in beta-amyloid plaque load, an increase in soluble beta-amyloid peptides and a decrease in insoluble forms. There was also significant improvement of cognitive deficits in this APP transgenic mouse model following intranasal but also peripheral treatment with three of these compounds. From this study it is concluded that the observed effects of the peptides derived from beta-synuclein N-terminus are depending on both, a direct interaction with aggregation of proteins, but also with

Topics: alpha-Synuclein; Animals; Enzyme Inhibitors; Humans; Neurodegenerative Diseases; Serine

Topics: alpha-Synuclein; Caveolae; Cholesterol; Humans; Lipid Metabolism; Membrane Microdomains; Membrane Proteins; Nervous System; Nervous System Diseases; Neurodegenerative Diseases

Synucleinopathies are characterized by the presence of different types of alpha-synuclein (AS)-positive inclusion in the brain. Thus, whereas Lewy bodies are the hallmark of Parkinson disease and dementia with Lewy bodies, glial and neuronal cytoplasmic inclusions are shown by multiple system atrophy. Because the main component of all these inclusions is conformationally modified AS, aggregation of the latter is thought to be a key pathogenic event in these diseases. Although very little information has been available on AS function and aggregation mechanisms until 2 years ago, recent investigations have greatly improved our understanding of the steps involved in the pathogenesis of synucleinopathies. Additionally, important insights into the specific molecular events (e.g. differential posttranslational modifications or isoform expression profiles) underlying each of these conditions have been gained. The present review summarizes our current knowledge of the commonalities and differences shown by protein aggregation mechanisms in the various synucleinopathies.

Topics: alpha-Synuclein; Animals; Humans; Inclusion Bodies; Neurodegenerative Diseases

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

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

Topics: alpha-Synuclein; Animals; Humans; Models, Biological; Nerve Degeneration; Neurodegenerative Diseases

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Neuroprotective Agents

In the last 50 years, an enormous amount of progress has been made in dissecting the etiology of hereditary neurodegenerative diseases, including the dementias, the parkinsonisms, the ataxias and the motor-neuron diseases. In addition, these genetic findings are beginning to provide insights into the pathogeneses of the sporadic forms of the diseases. Through animal and cellular modeling studies we are beginning to gain insights into the pathogenic pathways to disease. This mechanistic understanding is now leading to therapeutic strategies based on this new understanding. As yet, however, no mechanistic therapies are in use in the clinic.

Topics: alpha-Synuclein; Animals; Humans; Models, Biological; Neurodegenerative Diseases; Peptides; tau Proteins

In recent years, the term "conformational disease" has been used to describe a range of disorders which are linked to misfolding and aberrant structural change in proteins. The molecular bases underlying the pathogenesis of neurodegenerative diseases are gradually being disclosed, and almost all of the diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and prion disease are increasingly being realized to have common molecular mechanisms including the accumulation of misfolded or aggregation-prone proteins, thus, they can be termed "neurodegenerative conformational disease". There is now increased understanding of the molecular pathways involved in protein misfolding and aggregation and cellular toxicity in neurodegenerative conformational diseases. These are leading to approaches toward rational therapeutics.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Endoplasmic Reticulum; Neurodegenerative Diseases; Protein Conformation; Protein Folding; PrPC Proteins

Neurodegenerative diseases such as Huntington's, Parkinson's and Alzheimer's diseases are marked by neuronal accumulation of toxic misfolded protein. Developing therapies for these misfolding diseases requires finding chemical compounds that can either clear toxic misfolded protein, or can protect neurons from their impact. Such compounds could not only provide the starting points for potential drugs, but could also provide valuable research tools for untangling the complexities of the disease process. Until now, chemical screens for these diseases have focused on finding compounds that prevent aggregation of mutant protein. We recently published a compound, B2, which promotes the formation of large inclusions by mutant Huntingtin and alpha-synuclein, while rescuing some of the toxic effects of these proteins. As inclusions were long believed to be toxic to cells, this contradicts previous therapeutic approaches. At the same time, the results support growing evidence for the protective effects of inclusions. In this review, we discuss these results, and place them in the context of ongoing therapeutic discovery efforts for Huntington's disease and other neurodegenerative diseases.

Topics: alpha-Synuclein; Humans; Inclusion Bodies; Mutant Proteins; Neurodegenerative Diseases; Neuroprotective Agents; Nitroquinolines

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

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

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

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

The diagnosis of degenerative dementias heavily relies on the identification of neuronal or glial inclusions. Tauopathy is probably the largest group including Alzheimer and Pick disease, mutation of the tau gene, progressive supranuclear palsy, corticobasal degeneration, and argyrophilic grain disease. Lewy bodies, when numerous in the cerebral cortex, are usually associated with the cognitive deficit of Parkinson disease dementia or of dementia with Lewy bodies--both conditions being distinguished by clinical information. The inclusions of the dentate gyrus, only labeled by anti-ubiquitin antibodies, isolate a subgroup of fronto-temporal dementia (FTDu), sometimes familial and sometimes associated with amyotrophic lateral sclerosis. Mutations of the progranulin gene have been recently discovered among a significant proportion of these patients. Neuronal Intermediate Filament Inclusion Disease (NIFID) is a rare, apparently sporadic dementia, characterized by the presence of large inclusions in the cell body of many neurons. These inclusions react with antibodies directed against neurofilaments or against other intermediate filaments (such as alpha-internexin). The diagnostic value of some of these inclusions allowing the classification of the degenerative dementias has been discussed. The link between the inclusions and the pathogenetic mechanism is indeed probably variable. It should however be stressed that whenever their composition has been elucidated, the inclusions have given important clues to the pathogenesis of the disease in which they had been found.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Brain; Dementia; Humans; Neurodegenerative Diseases; Oligodendroglia; Pick Disease of the Brain; Tauopathies; Ubiquitin

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

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

Recently, we demonstrated that soluble 30-50 nm-sized annular alpha-synuclein oligomers are released by mild detergent treatment from glial cytoplasmic inclusions (GCIs) purified from multiple system atrophy brain tissue (Pountney et al., J. Neurochem. 90:502, 2004). Dynamic antibody recognition imaging using a specific anti-alpha-synuclein antibody confirmed that the annular structures were positive for alpha-synuclein. This showed that pathological alpha-synucleinopathy aggregates can be a source of annular alpha-synuclein species. In contrast to pathological alpha-synuclein, recombinant alpha-synuclein yielded only spherical oligomers after detergent treatment, indicating a greater propensity of the pathological protein to form stable annular oligomers. In vitro, we found that Ca2+ binding to monomeric alpha-synuclein, specifically amongst a range of different metal ions, induced the rapid formation of annular oligomers (Lowe et al., Protein Sci.,13:3245, 2004). Hence, alpha-synuclein speciation may also be influenced by the intracytoplasmic Ca2+ concentration. We also showed that annular alpha-synuclein oligomers can nucleate filament formation. We hypothesize that soluble alpha-synuclein annular oligomers may be cytotoxic species, either by interacting with cell membranes or components of the ubiquitin proteasome system. The equilibrium between alpha-synuclein species may be influenced by intracellular Ca2+ status, interaction with lipid vesicles or other factors.

Topics: alpha-Synuclein; Animals; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins

Alpha-synuclein is a 140 amino acid neuronal protein that has been associated with several neurodegenerative diseases. A point mutation in the gene coding for the alpha-synuclein protein was the first discovery linking this protein to a rare familial form of Parkinson's disease (PD). Subsequently, other mutations in the alpha-synuclein gene have been identified in familial PD. The aggregated proteinaceous inclusions called Lewy bodies found in PD and cortical Lewy body dementia (LBD) were discovered to be predominantly alpha-synuclein. Aberrant aggregation of alpha-synuclein has been detected in an increasing number of neurodegenerative diseases, collectively known as synucleopathies. Alpha-synuclein exists physiologically in both soluble and membrane-bound states, in unstructured and alpha-helical conformations, respectively. The physiological function of alpha-synuclein appears to require its translocation between these subcellular compartments and interconversion between the 2 conformations. Abnormal processing of alpha-synuclein is predicted to lead to pathological changes in its binding properties and function. In this review, genetic and environmental risk factors for alpha-synuclein pathology are described. Various mechanisms for in vitro and in vivo alpha-synuclein aggregation and neurotoxicity are summarized, and their relevance to neuropathology is explored.

Topics: alpha-Synuclein; Animals; Brain; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Rats; Synucleins

Biochemical and genetic evidence point towards alpha-synuclein aggregation as having a pivotal role in the onset and progression of several neurodegenerative disorders, including Parkinson's disease, multiple system atrophy and Lewy body dementia. We review recent data on how alpha-synuclein aggregates may impact on cellular homeostatic mechanisms including cellular transport and degradation and transcriptional regulation. alpha-Synuclein aggregates can exist as several molecular species and their different features are discussed in the context of the methodologies used for their study and the many chemical and physical factors that influence their formation.

Topics: alpha-Synuclein; Animals; Biochemical Phenomena; Chemistry Techniques, Analytical; Humans; Models, Molecular; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins

Topics: alpha-Synuclein; Animals; Humans; Movement Disorders; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins; tau Proteins

The variety of factors and events involved in neurodegeneration renders the subject a major challenge. Neurodegenerative disorders include a number of different pathological conditions, which share similar critical metabolic processes, such as protein aggregation and oxidative stress, both of which are associated with the involvement of metal ions. In this review, Alzheimer's disease, Parkinson's disease and prion disease are discussed, with the aim of identifying common trends underlying these devastating neurological conditions. Chelation therapy could be a valuable therapeutic approach, since metals are considered to be a pharmacological target for the rationale design of new therapeutic agents directed towards the treatment of neurodegeneration.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Chelating Agents; Copper; Humans; Ions; Iron; Manganese; Metals; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Prion Diseases; Prions; Proteins

This review highlights the role of oxidative stress and imbalances in metal ion homeostasis in the neurodegenerative diseases Alzheimer's disease and Parkinson's disease and in the progressive demyelinating disease multiple sclerosis. The chemistry and biochemistry of oxidative stress-induced protein damage are first described, followed by the evidence for a pathological role of oxidative stress in these disease states. It is tempting to speculate that free radical oxygen chemistry contributes to pathogenesis in all these conditions, though it is as yet undetermined what types of oxidative changes occur early in the disease, and what types are secondary manifestations of neuronal degeneration.

Topics: Aldehydes; alpha-Synuclein; Alzheimer Disease; Animals; Cross-Linking Reagents; Encephalomyelitis, Autoimmune, Experimental; Free Radicals; Glycation End Products, Advanced; Humans; Lipid Peroxidation; Malondialdehyde; Metals; Mice; Multiple Sclerosis; Neurodegenerative Diseases; Oxidation-Reduction; Oxidative Stress; Parkinson Disease; Proteins; Rats; Reactive Oxygen Species

There is strong evidence for the involvement of alpha-synuclein in the pathologies of several neurodegenerative disorders, including PD (Parkinson's disease). Development of disease appears to be linked to processes that increase the rate at which alpha-synuclein forms aggregates. These processes include increased protein concentration (via either increased rate of synthesis or decreased rate of degradation), and altered forms of alpha-synuclein (such as truncations, missense mutations, or chemical modifications by oxidative reactions). Aggregated forms of the protein are toxic to cells and one therapeutic strategy would be to reduce the rate at which aggregation occurs. To this end we have designed several peptides that reduce alpha-synuclein aggregation. A cell-permeable version of one such peptide was able to inhibit the DNA damage induced by Fe(II) in neuronal cells transfected with alpha-synuclein (A53T), a familial PD-associated mutation.

Topics: alpha-Synuclein; Amino Acid Sequence; Humans; Molecular Sequence Data; Neurodegenerative Diseases

Synucleins are a family of small, highly charged proteins expressed predominantly in neurons. Since their discovery and characterization during the last decade, much has been learned about their structure, potential functions, interactions with other proteins, and roles in disease. One of these proteins, alpha-synuclein (alpha-syn), is the major building block of pathological inclusions that characterize many neurodegenerative disorders, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and neurodegeneration with brain iron accumulation type 1 (NBIA-1), which collectively are termed synucleinopathies. Furthermore, genetic and biological studies support a role for alpha-syn in the pathophysiology of these diseases. Therefore, research must be continued in order to better understand the functions of the synuclein proteins under normal physiological conditions as well as their role in diseases.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Animals, Genetically Modified; Dementia; Humans; Lewy Bodies; Models, Biological; Models, Chemical; Molecular Sequence Data; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Nitrogen; Oxygen; Parkinson Disease; Pesticides; Protein Binding; Sequence Homology, Amino Acid; Synucleins

Topics: alpha-Synuclein; Animals; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Phosphorylation; Protein Structure, Tertiary; Synucleins; tau Proteins; Tauopathies

Selective dopaminergic cell loss in Parkinson's disease is correlated with increased levels of cellular iron. It is still hotly debated as to whether the increase in iron is an upstream event which acts to promote neurodegeneration via formation of oxidative stress or whether iron accumulates as a by-product of the neuronal cell loss. Here we review evidence for loss of iron homeostasis as a causative factor in disease-associated neurodegeneration and the primary players which may be involved. A series of recent studies suggest that iron regulatory proteins (IRPs) coordinate both cellular iron levels and energy metabolism, both of which are disrupted in Parkinson's disease (PD) and may in turn contribute to increased levels of oxidative stress associated with the disease. Iron has also been recently been implicated in promotion of alpha-synuclein aggregation either directly or via increasing levels of oxidative stress suggesting an important role for it in Lewy body formation, another important hallmark of the disease.

Topics: alpha-Synuclein; Animals; Homeostasis; Humans; Iron; Iron Regulatory Protein 1; Iron Regulatory Protein 2; Iron-Regulatory Proteins; Mesencephalon; Mitochondria; Models, Biological; Nerve Tissue Proteins; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Protein Binding; Synucleins

A process of protein aggregation that causes intracellular or extracellular accumulation of insoluble protein deposits causes many important neurodegenerative diseases associated with the ageing. The recognition that protein aggregation plays a prominent role in pathogenesis of important pathologies such as Alzheimer's and Parkinson's diseases prompted the scientific community to focus on the molecular mechanism of protein aggregation. Many proteins with sophisticated functions can self-aggregate because their folding is complicate and abnormal intermolecular contacts can predominate over the normal intramolecular interactions. The review of biochemical functional and pathogenic implications attributed to alpha synuclein, A beta peptide, presenilin and apoE highlights for these proteins a common conformational plasticity and the capacity to adapt their secondary structure to surrounding solvent as well as to the contacted ligands. Their functions are not fully elucidated but there is an elevated number of metabolic pathways in which apparently they are involved as well as they generate functional contact with a remarkable number of other proteins. The mechanism by which alpha synuclein and A beta protein make fibrils is an example of conformational plasticity because both these polypeptides can visit a coil or helical structure, but otherwise they convert into a pathogenic beta sheet structure highly suitable for polymerisation and fibril formation. The emerging question in the puzzling pathogenic basis of these diseases is if protein aggregation associated with ageing has a role in molecular evolution of the species or if it just represents a calculated drawback.

Topics: Aging; alpha-Synuclein; Amyloid beta-Peptides; Animals; Apolipoproteins E; Humans; Membrane Proteins; Nerve Tissue Proteins; Neurodegenerative Diseases; Presenilin-1; Presenilin-2; Proteins; Synucleins

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

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

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

Ubiquitinated inclusions and selective neuronal cell death are considered the pathological hallmarks of Parkinson's disease and other neurodegenerative diseases. Recent genetic, pathological and biochemical evidence suggests that dysfunction of ubiquitin-dependent protein degradation by the proteasome might be a contributing, if not initiating factor in the pathogenesis of these diseases. In neuronal cell culture models inhibition of the proteasome leads to cell death and formation of fibrillar ubiquitin and alpha-synuclein-positive inclusions, thus modeling some aspects of Lewy body diseases. The processes of inclusion formation and neuronal cell death share some common mechanisms, but can also be dissociated at a certain level.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Cell Death; Humans; Inclusion Bodies; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; Synucleins; Ubiquinone

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

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

Alpha-synuclein is regarded as a presynaptic protein, which may play an important role in neuronal plasticity. However, the actual physiological function of this protein is not completely clear. Abnormal accumulation of fibrillar alpha-synuclein in Lewy bodies, as well as mutations in the alpha-synuclein gene identified in the familial forms of Parkinson's disease, point to a central role of this protein in the pathophysiology of Lewy body-related disorders. In vivo and in vitro studies showed that overexpression of alpha-synuclein, its aggregation, and interaction with other proteins are the most critical factors affecting the survival of neurons. In Alzheimer's disease, the amount of alpha-synuclein is found to be elevated at synapses, whereas a peptide derived from alpha-synuclein is thought to represent an intrinsic component of amyloid plaques. It is likely that in this disorder alpha-synuclein plays a dual role by being involved not only in synaptic function but also in amyloid beta-fibrillogenesis.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Humans; Lewy Bodies; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Plaque, Amyloid; Presynaptic Terminals; Synucleins

Alpha-synuclein (alphaSN) brain pathology is a conspicuous feature of several neurodegenerative diseases. These include prevalent conditions such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and the Lewy body variant of Alzheimer's disease (LBVAD), as well as rarer conditions including multiple systems atrophy (MSA), and neurodegeneration with brain iron accumulation type-1 (NBIA-1). Common in these diseases, some referred to as alpha-synucleinopathies, are microscopic proteinaceous insoluble inclusions in neurons and glia that are composed largely of fibrillar aggregates of alphaSN. This molecular form of alphaSN contrasts sharply with normal alphaSN, which is an abundant soluble presynaptic protein in brain neurons. alphaSN is a highly conserved protein in vertebrates and only seven of its 140 amino acids differ between human and mouse. Flies lack an alphaSN gene. Implicated in neurotoxicity are two alphaSN mutants (A53T and A30P) that cause extremely rare familial forms of PD, alphaSN fibrils and protofibrils, soluble protein complexes of alphaSN with 14-3-3 protein, and phosphorylated, nitrosylated, and ubiquitylated alphaSN species. Unlike rare forms of fPD caused by mutations in alphaSN, disease mechanisms in most alpha-synucleinopathies implicate wildtype alphaSN and seem to converge around oxidative damage and impairments in protein catabolism. It is not known whether these causalities involve alphaSN from the beginning, but defects in the handling of this protein seem to contribute to disease progression because accumulation of toxic alphaSN forms damage neurons. Here, we summarize the main structural features of alphaSN and its functions, and discuss the molecular alphaSN species implicated in human disease and transgenic animal models of alpha-synucleinopathy in fly and rodents.

Topics: alpha-Synuclein; Alzheimer Disease; Amino Acid Sequence; Animals; Humans; Lewy Body Disease; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synucleins

Hallmark lesions of neurodegenerative synucleinopathies contain alpha-synuclein (alpha-syn) that is modified by nitration of tyrosine residues and possibly by dityrosine cross-linking to generated stable oligomers. Data gathered from in vitro experiments and from model systems of cells transfected with wild-type and mutant alpha-syn revealed that conditions resulting in alpha-syn nitration also induce formation of alpha-syn inclusions with similar biochemical characteristics to protein extracted from human lesions. The detection of tyrosine-nitrated alpha-syn signifies the formation of reactive nitrogen species capable of both radical and electrophilic attack on aromatic residues as well as nucleophilic additions and oxidations. The cellular sources and biochemical reactivity of reactive nitrogen species in the central nervous system remain largely unknown, but kinetically fast reactions of nitric oxide with superoxide to form peroxynitrite as well as enzymatic one-electron oxidation of nitrite are two important sources of reactive nitrogen species. Based on these findings a model is proposed where the process of fibrilization can be differentially affected by oxidants and nitrating species. Posttranslational modifications of alpha-syn by reactive nitrogen species inhibits fibril formation and results in urea- and SDS- insoluble, protease-resistant alpha-syn aggregates that maybe responsible for cellular toxicity.

Topics: alpha-Synuclein; Animals; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Nitrates; Oxidative Stress; Protein Processing, Post-Translational; Synucleins

Quantitative neuropsychiatry has provided increasingly precise descriptions of behavioral phenotypes associated with neurodegenerative disorders. Degenerative diseases of the brain are disturbances of protein metabolism, with failure of protein degredation by the ubiquitin-proteosome system, production of neurotoxic peptide oligomers, and accumulation of intracellular protein deposits. Abnormalities of amyloid beta peptide, alpha-synuclein protein, and hyperphosphorylated tau protein account for more than 90% of degenerative dementias. Functionally related neuroanatomical systems have shared metabolic characteristics and common vulnerabilities to protein dysmetabolism, providing the basis for phenotypes that reflect the underlying proteotype. Patients with alpha-synuclein disorders are particularly prone to hallucinations, delusions, and rapid eye movement sleep behavior disorder. Patients with tauopathies manifest disproportionate disinhibition and apathy, and may exhibit compulsions. Alzheimer's disease is a triple proteinopathy with abnormalities of A-beta, tau, and alpha-synculein leading to a complex behavioral phenotype. This molecular approach to neuropsychiatry may assist in understanding the mechanisms of degenerative diseases, provide insight into the pathophysiology of neuropsychiatric symptoms, and contribute to monitoring disease-modifying therapies.

Topics: alpha-Synuclein; Alzheimer Disease; Biological Psychiatry; Genotype; Humans; Nerve Tissue Proteins; Neurobiology; Neurodegenerative Diseases; Phenotype; Synucleins

Under the physiological conditions in vitro, alpha-synuclein, a conservative presynaptic protein, the aggregation and fibrillation of which is assumed to be involved into the pathogenesis of Parkinson's disease and several other neurodegenerative disorders, known as synucleinopathies, is characterized by the lack of rigid well-defined structure; i.e., it belongs to the class of intrinsically unstructured proteins. Intriguingly, alpha-synuclein is characterized by a remarkable conformational plasticity, adopting a series of different conformations depending on the environment. For example, this protein may either stay substantially unfolded, or adopt an amyloidogenic partially folded conformation, or fold into alpha-helical or beta-structural species, both monomeric and oligomeric. Furthermore, it might form several morphologically different types of aggregates, including oligomers (spheres or doughnuts), amorphous aggregates, and or amyloid-like fibrils. The peculiarities of this astonishing conformational behavior are analyzed to shed light on structural plasticity of this protein-chameleon.

Topics: Alcohols; alpha-Synuclein; Animals; Humans; Hydrogen-Ion Concentration; Metals; Models, Molecular; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Pesticides; Polymers; Protein Conformation; Protein Folding; Synucleins

Alpha-synuclein belongs to a family of vertebrate proteins, encoded by three different genes: alpha, ss, and gamma. The protein has become of interest to the neuroscience community in the last few years after the discovery that a mutation in the alpha-synuclein gene is associated with familial autosomal-dominant early-onset forms of Parkinson Disease. However, it is not yet clear how the protein is involved in the disease. Several studies have suggested that alpha-synuclein plays a role in neurotransmitter release and synaptic plasticity. This hypothesis might help elucidate how alpha-synuclein malfunctioning contributes to the development of a series of disorders known as synucleinopathies.

Topics: alpha-Synuclein; Animals; Environment; Humans; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synapses; Synaptic Transmission; Synucleins; Ubiquinone; Ubiquitin-Protein Ligases

Synucleinopathies comprise a diverse group of neurodegenerative proteinopathies that share common pathological lesions composed of aggregates of conformational and posttranslational modifications of alpha-synuclein in selected populations of neurons and glia. Abnormal filamentous aggregates of misfolded alpha-synuclein protein are the major components of Lewy bodies, dystrophic (Lewy) neurites, and the Papp-Lantos filaments in oligodendroglia and neurons in multiple system atrophy linked to degeneration of affected brain regions. The synucleinopathies include (1) Lewy body disorders and dementia with Lewy bodies, (2) multiple system atrophy (MSA), and (3) Hallervorden-Spatz disease. (1) The pathological diagnosis of Lewy body disorders and dementia with Lewy bodies is established by validated consensus criteria based on semiquantitative assessment of subcortical and cortical Lewy bodies as their common hallmarks. They are accompanied by subcortical multisystem degeneration with neuronal loss and gliosis with or without Alzheimer pathologic state. Lewy bodies also occur in numerous other disorders, including pure autonomic failure, neuroaxonal dystrophies, and various amyloidoses and tauopathies. (2) Multiple system atrophy, a sporadic, adult-onset degenerative movement disorder of unknown cause, is characterized by alpha-synuclein-positive glial cytoplasmic and rare neuronal inclusions throughout the central nervous system associated with striatonigral degeneration, olivopontocerebellar atrophy, and involvement of medullar and spinal autonomic nuclei. (3) In neurodegeneration with brain iron accumulation type I, or Hallervorden-Spatz disease, alpha-synuclein is present in axonal spheroids and glial and neuronal inclusions. While the identity of the major components of Lewy bodies suggests that a pathway leading from normal soluble to abnormal misfolded filamentous proteins is central for their pathogenesis, regardless of the primary disorder, there are conformational differences in alpha-synuclein between neuronal and glial aggregates, showing nonuniform mapping for its epitopes. Despite several cellular and transgenic models, it is not clear whether inclusion body formation is an adaptive/neuroprotective or a pathogenic reaction/process generated in response to different, mostly undetermined, functional triggers linked to neurodegeneration.

Topics: alpha-Synuclein; Brain; Humans; Lewy Bodies; Lewy Body Disease; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuroglia; Neurons; Synucleins

The term synucleinopathies is used to name a group of neurodegenerative disorders characterized by fibrillary aggregates of alpha-synuclein protein in the cytoplasm of selective populations of neurons and glia. These disorders include Parkinson's disease (PD), dementia with Lewy bodies (DLB), pure autonomic failure (PAF), and multiple system atrophy (MSA). Clinically, they are characterized by a chronic and progressive decline in motor, cognitive, behavioural, and autonomic functions, depending on the distribution of the lesions. Because of clinical overlap, differential diagnosis is sometimes very difficult. Parkinsonism is the predominant symptom of PD, but it can be indistinguishable from the parkinsonism of DLB and MSA. Autonomic dysfunction, which is an isolated finding in PAF, may be present in PD and DLB, but is usually more prominent and appears earlier in MSA. DLB could be the same disease as PD but with widespread cortical pathological states, leading to dementia, fluctuating cognition, and the characteristic visual hallucinations. The deposition of aggregates of synuclein in neurons and glia suggests that a common pathogenic mechanism may exist for these disorders. Even though synuclein may play an important role in disease development in these disorders, in light of the different symptom complex and prognosis and management issues that characterize each disorder, we think that the term synucleinopathy has little practical value as a diagnostic term for the clinician. Clinicians should attempt to reach standard clinical diagnosis on patients, such as PD, PAF, or MSA.

Topics: alpha-Synuclein; Brain; Diagnosis, Differential; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrils; Neuroglia; Neurologic Examination; Neurons; Synucleins

Alpha-Synuclein is a core component of the proteinaceous aggregates observed in several neurodegenerative diseases. A central role of alpha-synuclein in neurodegeneration was demonstrated by the discovery of missense alpha-synuclein mutations in familial Parkinson's disease. However, the specific mechanism by which alpha-synuclein contributes to these diseases remains unclear. A recent study by Sharon et al. linked the presence of specific fatty acids to the appearance of alpha-synuclein oligomers in vivo. alpha-Synuclein oligomers might be a first step in the formation of alpha-synuclein aggregates present in a number of neurodegenerative diseases, although their cytotoxicity remains to be directly demonstrated.

Topics: alpha-Synuclein; Animals; Fatty Acids; Humans; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synucleins

The discovery of two missense mutations in alpha-synuclein gene and the identification of the alpha-synuclein as the major component of Lewy bodies and Lewy neurites have imparted a new direction in understanding Parkinson's disease. Now that alpha-synuclein has been implicated in several neurodegenerative disorders makes it increasingly clear that aggregation of alpha-synuclein is a hallmark feature in neurodegeneration. Although little has been learned about its normal function, alpha-synuclein appears to be associated with membrane phospholipids and may therefore participate in a number of cell signaling pathways. Here, we review the localization, structure, and function of alpha-synuclein and provide a new hypothesis on, (a) the disruption in the membrane binding ability of synuclein which may be the major culprit leading to the alpha-synuclein aggregation and (b) the complexity associated with nuclear localization of alpha-synuclein and its possible binding property to DNA. Further, we postulated the three possible mechanisms of synuclein induced neuronal degeneration in Parkinson's disease.

Topics: alpha-Synuclein; Macromolecular Substances; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; Protein Binding; Protein Conformation; Protein Folding; Structure-Activity Relationship; Synucleins

The various protein deposits of brain amyloidosis share common ultrastructural, biophysical, and histological properties. These amyloidogenic deposits can be composed of distinct proteins, which are conceptually associated with different neurodegenerative diseases. Amyloidogenic proteins are typically soluble monomeric precursors, which undergo remarkable conformation changes associated with the polymerization into 8- to 10-nm wide fibrils, which culminate in the formation of amyloid aggregates. Some amyloidogenic inclusions are extracellular, such as senile plaques of Alzheimer's disease, which are composed of amyloid beta (Abeta) peptides. However, intracytoplasmic amyloid aggregates, such as neurofibrillary tangles in Alzheimer's disease and Lewy bodies in Parkinson's disease, are composed of the proteins tau and alpha-synuclein, respectively. The mounting awareness that the latter proteins are directly linked to the etiology of spectrum of neurodegenerative diseases has resulted in the coining of the terms "tauopathies" and "synucleinopathies." However, emerging evidence for the overlap in the pathological and clinical features of patients with brain amyloidosis suggests that they may be linked mechanistically. Recently, it was demonstrated that alpha-synuclein, which has the ability to readily form amyloid in vitro without the need of other co-factors, can initiate tau amyloid formation. Following this initiation step, alpha-synuclein and tau can synergize the polymerization of each other. Furthermore, increased levels of Abeta peptides in brain can promote the formation of intracellular tau and alpha-synuclein amyloid aggregates, although the mechanism for this process is still unclear. These results indicate that the formation of amyloid composed of different proteins can affect each other directly or indirectly, likely contributing to the overlap in clinical and pathological features.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Plaque, Amyloid; Polymers; Synucleins; tau Proteins

Abnormalities of tau and alpha-synuclein have been described in a variety of neurodegenerative diseases often associated with sleep disorders. Neuropathological descriptions concerning these diseases are rapidly expanding, and they become difficult to summarise. On the other hand, the human neuroanatomy of sleep remains an ill defined issue. Main tauopathies are Alzheimer's disease, progressive supranuclear palsy, cortico-basal degeneration, argyrophilic grain disease, Pick disease and fronto-temporal degeneration with Parkinsonism associated with chromosome 17. In contrast to Alzheimer's disease, where abnormal tau containing cells are mainly neurones, in the other disorders, both neurones and glial cells are affected. The presynaptic protein alpha-synuclein is a major constituent of Lewy-type lesions in Parkinson disease and in dementia with Lewy bodies. Alpha-synuclein is also found in neurones and glia of Multi System Atrophy. This led to group these disorders into the still ill defined group of synucleinopathies. The lesions of tauopathies and synucleinopathies are presented, and their distribution in the most common disorders is described, distinguishing when possible neuronal loss and neuropathological markers. Recent data show that their extension is far larger than previously assumed and that they involve a variety of areas possibly involved in sleep regulation. Sleep disorders have been described in various tauopathies and synucleinopathies. However, no detailed clinico-pathological reports concerning the distribution of affected and spared areas in patients studied by polysomnography are available. Furthermore, the similarities of sleep disorders associated with different diseases, the interindividual variability, the frequently associated disorders, and the difficulties in quantifying neuronal loss make any clinicopathological correlation uncertain. The knowledge of sleep neuroanatomy is mainly based on animal studies. The few data concerning the structures of human brain areas involved in sleep organisation are recalled. Several systems known to be acting in sleep physiology are usually affected by tauopathies and synucleinopathies, but the pattern of their involvement in sleep pathology remains highly conjectural. The neuropathology of sleep disorders in tauopathies and synucleinopathies is a still uncultivated field.

Topics: Adult; Aged; alpha-Synuclein; Brain Chemistry; Humans; Lewy Bodies; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases; Sleep Wake Disorders; Synucleins; tau Proteins; Tauopathies

Multiple lines of evidence implicate lysosomes in a variety of pathogenic events that produce neurodegeneration. Genetic mutations that cause specific enzyme deficiencies account for more than 40 lysosomal storage disorders. These mostly pre-adult diseases are associated with abnormal brain development and mental retardation. Such disorders are characterized by intracellular deposition and protein aggregation, events also found in age-related neurodegenerative diseases including (i) Alzheimer's disease and related tauopathies (ii) Lewy body disorders and synucleinopathies such as Parkinson's disease, and (iii) Huntington's disease and other polyglutamine expansion disorders. Of particular interest for this review is evidence that alterations to the lysosomal system contribute to protein deposits associated with different types of age-related neurodegeneration. Lysosomes are in fact highly susceptible to free radical oxidative stress in the aging brain, leading to the gradual loss of their processing capacity over the lifespan of an individual. Several studies point to this lysosomal disturbance as being involved in amyloidogenic processing, formation of paired helical filaments, and the aggregation of alpha-synuclein and mutant huntingtin proteins. Most notably, experimentally induced lysosomal dysfunction, both in vitro and in vivo, recapitulates important pathological features of age-related diseases including the link between protein deposition and synaptic loss.

Topics: alpha-Synuclein; Amyloid; Animals; Humans; Huntingtin Protein; Lysosomal Storage Diseases, Nervous System; Lysosomes; Macromolecular Substances; Nerve Tissue Proteins; Neurodegenerative Diseases; Nuclear Proteins; Protein Processing, Post-Translational; Synucleins; tau Proteins

Parkinson's disease (PD) is the most common neurodegenerative movement disorder. While the classic clinical-neuropathological features of PD have been well established, mechanisms underlying brain degeneration in PD are unknown, and only partially effective symptomatic treatments for PD exist. Further, there are no therapeutic interventions that prevent PD or block the progression of this relentless neurodegenerative disorder. However, dramatic new insights into the role of alpha-synuclein (AS) in the pathobiology of PD have emerged recently, and this has led to the development of transgenic animal models of PD-like AS pathologies. Continuing advances in this research direction should advance understanding of PD and accelerate discovery of more effective therapies for this and related synucleinopathies.

Topics: alpha-Synuclein; Amyloidosis; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synucleins

Lewy body disease includes clinically and pathologically defined disorders in which Lewy bodies occur in the nervous system. In recent years, the molecular features of these disorders have been emerging. Several genetic loci have been identified in association with familial Lewy body disease; however, the genetic risks underlying most cases of familial Lewy body disease remain to be discovered. The fact that Lewy bodies stain strongly with antibodies to asynuclein and that mutations in the alpha-synuclein gene lead to syndromes in which parkinsonism and dementia occur gives us important clues regarding the biologic processes leading to disease. Pursuit of additional mendelian causes of familial Lewy body disease and study of the factors contributing to the complex phenotypes associated with Lewy body disorders will elucidate underlying disease pathways and, thus, possible targets for therapeutic intervention.

Topics: Aged; alpha-Synuclein; Brain; Chromosomes, Human, Pair 4; Genetic Predisposition to Disease; Humans; Lewy Bodies; Lewy Body Disease; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins

Synucleins are small, soluble proteins expressed primarily in neural tissue and in certain tumors. The family includes three known proteins: alpha-synuclein, beta-synuclein, and gamma-synuclein. All synucleins have in common a highly conserved alpha-helical lipid-binding motif with similarity to the class-A2 lipid-binding domains of the exchangeable apolipoproteins. Synuclein family members are not found outside vertebrates, although they have some conserved structural similarity with plant 'late-embryo-abundant' proteins. The alpha- and beta-synuclein proteins are found primarily in brain tissue, where they are seen mainly in presynaptic terminals. The gamma-synuclein protein is found primarily in the peripheral nervous system and retina, but its expression in breast tumors is a marker for tumor progression. Normal cellular functions have not been determined for any of the synuclein proteins, although some data suggest a role in the regulation of membrane stability and/or turnover. Mutations in alpha-synuclein are associated with rare familial cases of early-onset Parkinson's disease, and the protein accumulates abnormally in Parkinson's disease, Alzheimer's disease, and several other neurodegenerative illnesses. The current challenge is to understand the normal cellular function of these proteins and how they might contribute to the development of human disease.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; beta-Synuclein; Evolution, Molecular; gamma-Synuclein; Humans; Models, Molecular; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Phylogeny; Sequence Alignment; Sequence Homology, Amino Acid; Synucleins

Parkinson's disease (PD) is the most common neurodegenerative motor disorder, marked by chronic progressive loss of neurons in the substantia nigra, thereby damaging purposeful control of movement. For decades, it was believed that PD was caused solely by environmental causes. However, the discovery of genetic factors involved in PD has revolutionized our attempts to understand the disease's pathology. PD now appears to be more polygenetic than previously thought and is most likely caused by a complex interaction of genetic risks and environmental exposures. The first gene found to be mutated in PD encodes for the presynaptic protein alpha-synuclein, which is also a major component of Lewy bodies and Lewy neurites, the neuropathological hallmarks of the disease. While these findings provide a classic example of how rare genetic mutations in disease can point to important pathways in idiopathic disease pathologies, much of the study of alpha-synuclein has focused on understanding how this protein undergoes the transition from an unfolded monomer to amorphous aggregates or Lewy body-like filaments rather than addressing what its fundamental function might be. Since alterations in synuclein function may predispose to the disease pathology of PD, regardless of the presence of genetic mutations, a more thorough understanding of the cellular regulation and function of alpha-synuclein may be of crucial importance to our understanding of this degenerating disorder.

Topics: alpha-Synuclein; Humans; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Phosphoproteins; Protein Conformation; Synucleins

The synucleinopathies are a diverse group of neurodegenerative disorders that share a common pathologic lesion composed of aggregates of insoluble alpha-synuclein protein in selectively vulnerable populations of neurons and glia. Growing evidence links the formation of abnormal filamentous aggregates to the onset and progression of clinical symptoms and the degeneration of affected brain regions in neurodegenerative disorders. These disorders may share an enigmatic symmetry, i.e., missense mutations in the gene encoding for the disease protein (alpha-synuclein) cause familial variants of Parkinson disease as well as its hallmark brain lesions, but the same brain lesions also form from the corresponding wild-type brain protein in the more common sporadic varieties of Parkinson disease. It is likely that clarification of this enigmatic symmetry in 1 form of synucleinopathy will have a profound impact on understanding the mechanisms underlying all these disorders. Furthermore, these efforts will likely lead to novel diagnostic and therapeutic strategies in regard to the synucleinopathies.

Topics: alpha-Synuclein; Animals; Humans; Lewy Body Disease; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synucleins

The most common degenerative diseases of the human brain are characterized by the presence of abnormal filamentous inclusions in affected nerve cells and glial cells. These diseases can be grouped into two classes, based on the identity of the major proteinaceous components of the filamentous assemblies. The filaments are made of either the microtubule-associated protein tau or the protein alpha-synuclein. Importantly, the discovery of mutations in the tau gene in familial forms of frontotemporal dementia and of mutations in the alpha-synuclein gene in familial forms of Parkinson's disease has established that dysfunction of tau protein and alpha-synuclein can cause neurodegeneration.

Topics: alpha-Synuclein; Amino Acid Sequence; Chromosomes, Human, Pair 17; Humans; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins; tau Proteins

Protein oxidation, one of a number of brain biomarkers of oxidative stress, is increased in several age-related neurodegenerative disorders or animal models thereof, including Alzheimer's disease, Huntington's disease, prion disorders, such as Creutzfeld-Jakob disease, and alpha-synuclein disorders, such as Parkinson's disease and frontotemporal dementia. Each of these neurodegenerative disorders is associated with aggregated proteins in brain. However, the relationship among protein oxidation, protein aggregation, and neurodegeneration remain unclear. The current rapid progress in elucidation of mechanisms of protein oxidation in neuronal loss should provide further insight into the importance of free radical oxidative stress in these neurodegenerative disorders.

Topics: Aging; alpha-Synuclein; Alzheimer Disease; Animals; Brain; Humans; Huntington Disease; Nerve Tissue Proteins; Neurodegenerative Diseases; Oxidation-Reduction; Prion Diseases; Synucleins

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

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

The term alpha-synucleinopathy is used to name a group of disorders having in common the abnormal deposition of alpha-synuclein in the cytoplasm of neurons or glial cells, as well as in extracellular deposits of amyloid. In Parkinson's disease and Lewy body dementia, alpha-synuclein is the main component of Lewy bodies and dystrophic neurites; alpha-synuclein also accumulates in the cytoplasm of glial cells. In multiple system atrophy, alpha-synuclein conforms the cytoplasmic oligodendroglial inclusions and the neuronal inclusions which are the hallmark of this disease. Finally, the amyloidogenic fragment 61-95 amino acids of alpha-synuclein is the non-Abeta component of senile plaque amyloid in Alzheimer disease. Accumulations of alpha-synuclein in all these disorders have in common a fibrilar configuration, but they differ in the binding of alpha-synuclein to distinct proteins with the exception of ubiquitin whose binding to alpha-synuclein is common to all alpha-synuclein inclusions. The mechanisms leading to alpha-synuclein fragmentation and aggegation into extracellular amyloid are not known, although alpha-synuclein fragment and betaA4 aggregates are the result of abnormal cleavage of large precursors. On the other hand, several studies have shown that alpha-synuclein may adopt a fibrilar conformation and give rise to insoluble forms and high molecular weight aggregates in vitro. Similar complexes have also been observed in alpha-synucleinopathies. Although studies in vitro and in vivo have shown toxic effects of alpha-synuclein, the consequence of alpha-synuclein deposition on cell survival in alpha-synucleinopathies is not known.

Topics: alpha-Synuclein; Alzheimer Disease; Cell Death; Cytoplasm; Humans; Lewy Body Disease; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuroglia; Neurons; Parkinson Disease; Synucleins

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

The deposition of abnormal protein fibrils is a prominent pathological feature of many different 'protein conformational' diseases, including some important neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), motor neurone disease and the 'prion' dementias. Some of the fibril-forming proteins or peptides associated with these diseases have been shown to be toxic to cells in culture. A clear understanding of the molecular mechanisms responsible for this toxicity should shed light on the probable link between protein deposition and cell loss in these diseases. In the case of the beta-amyloid (Abeta), which accumulates in the brain in AD, there is good evidence that the toxic mechanism involves the production of reactive oxygen species (ROS). By means of an electron spin resonance (ESR) spin-trapping method, we have shown recently that solutions of Abeta liberate readily detectable amounts of hydroxyl radicals upon incubation in vitro followed by the addition of small amounts of Fe(II). We have also obtained similar results with alpha-synuclein, which accumulates in Lewy bodies in PD. Our data suggest that hydrogen peroxide accumulates during Abeta or alpha-synuclein incubation and that this is subsequently converted to hydroxyl radicals, on addition of Fe (II), by Fenton's reaction. Consequently, we now support the idea that one of the fundamental molecular mechanisms underlying the pathogenesis of cell death in AD, PD, and possibly some other protein conformational diseases, could be the direct production of ROS during formation of the abnormal protein aggregates. This hypothesis suggests a novel approach to the therapy of this group of diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Electron Spin Resonance Spectroscopy; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Parkinson Disease, Secondary; Reactive Oxygen Species; Synucleins

Beginning with the isolation of the fragment of alpha-synuclein (alpha-syn) known as the non-Abeta component of amyloid plaques (NAC peptide) from Alzheimer's disease (AD) brains, alpha-syn has been increasingly implicated in the pathogenesis of neurodegenerative diseases, which now are classified as synucleinopathies. Indeed, unequivocal evidence linking abnormal alpha-syn to mechanisms of brain degeneration came from discoveries of missense mutations in the alpha-syn gene pathogenic for familial Parkinson's disease (PD) in rare kindreds. Shortly thereafter, alpha-syn was shown to be a major component of Lewy bodies (LBs) and Lewy neurites in sporadic PD, dementia with LBs (DLB) and the LB variant of AD. Also, studies of brains from patients with AD caused by genetic abnormalities demonstrated many alpha-syn positive LBs. Further, alpha-syn was implicated in the formation of the glial (GCIs) and neuronal cytoplasmic inclusions of multiple system atrophy, and the LBs, GCIs and neuraxonal spheroids of neurodegeneration with brain iron accumulation type 1. Recently, two other members of the synuclein family, beta- and gamma-synuclein, have also been recognized to play a role in the pathogenesis of novel axonal lesions in PD and DLB. Evidence for a role of alpha-syn in the formation of filamentous aggregates was reinforced by in vitro studies showing aggregation and fibrillogenesis of mutant and wild type alpha-syn. Indeed, since the aggregation of brain proteins into presumptively toxic lesions is emerging as a common but poorly understood mechanistic theme in sporadic and hereditary neurodegenerative diseases, clarification of the mechanism of synuclein aggregation could augment efforts to develop novel and more effective therapies for many neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; gamma-Synuclein; Humans; Lewy Bodies; Nerve Tissue Proteins; Neurodegenerative Diseases; Plaque, Amyloid; Synucleins

Synucleinsare small proteins that are highly expressed in brain tissue and are localised at presynaptic terminals in neurons. alpha-Synuclein has been identified as a component of intracellular fibrillar protein deposits in several neurodegenerative diseases, and two mutant forms of alpha-synuclein have been associated with autosomal-dominant Parkinson's Disease. A fragment of alpha-synuclein has also been identified as the non-Abeta component of Alzheimer's Disease amyloid. In this review we describe some structural properties of alpha-synuclein and the two mutant forms, as well as alpha-synuclein fragments, with particular emphasis on their ability to form beta-sheet on ageing and aggregate to form amyloid-like fibrils. Differences in the rates of aggregation and morphologies of the fibrils formed by alpha-synuclein and the two mutant proteins are highlighted. Interactions between alpha-synuclein and other proteins, especially those that are components of amyloid or Lewy bodies, are considered. The toxicity of alpha-synuclein and related peptides towards neurons is also discussing in relation to the aetiology of neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid; Base Sequence; Humans; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Conformation; Synucleins

Alzheimer's disease and Parkinson's disease are the most common neurodegenerative diseases. They are characterized by the degeneration of selected populations of nerve cells that develop filamentous inclusions before degeneration. The neuronal inclusions of Alzheimer's disease are made of the microtubule-associated protein tau, in a hyperphosphorylated state. Recent work has shown that the filamentous inclusions of Parkinson's disease are made of the protein alpha-synuclein and that rare, familial forms of Parkinson's disease are caused by missense mutations in the alpha-synuclein gene. Besides Parkinson's disease, the filamentous inclusions of two additional neurodegenerative diseases, namely dementia with Lewy bodies and multiple system atrophy, have also been found to be made of alpha-synuclein. Abundant filamentous tau inclusions are not limited to Alzheimer's disease. They are the defining neuropathological characteristic of frontotemporal dementias such as Pick's disease, and of progressive supranuclear palsy and corticobasal degeneration. The recent discovery of mutations in the tau gene in familial forms of frontotemporal dementia has provided a direct link between tau dysfunction and dementing disease. The new work has established that tauopathies and alpha-synucleinopathies account for most late-onset neurodegenerative diseases in man. The formation of intracellular filamentous inclusions might be the gain of toxic function that leads to the demise of affected brain cells.

Topics: alpha-Synuclein; Alzheimer Disease; Amino Acid Sequence; Humans; Inclusion Bodies; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrils; Neurons; Parkinson Disease; Phosphoproteins; Synucleins; tau Proteins

Synucleins are small highly conserved proteins in vertebrates, especially abundant in neurons and typically enriched at presynaptic terminals. Three genes in humans produce closely related synuclein proteins, all of which share a large amphipathic domain capable of reversible binding to lipid vesicles. Alpha synuclein has been specifically implicated in neurodegenerative disease. Two point mutations are genetically linked to familial Parkinson's disease, and alpha synuclein appears to form the major fibrillary component of Lewy bodies. Alpha synuclein also contributes to the intracellular inclusions of multiple system atrophy, and a fragment has been found in senile plaques in Alzheimer's disease. Although their normal cellular functions are unknown, several observations suggest the synucleins may serve to integrate presynaptic signaling and membrane trafficking. Alpha synuclein has been identified as a potent and selective inhibitor of phospholipase D2, which produces phosphatidic acid (to which synuclein binds) and is believed to function in the partitioning of membranes between the cell surface and intracellular stores. We outline a hypothesis whereby synuclein supports localized, experience-dependent turnover of synaptic membranes. Such a process may be important for lifelong learning and memory functions and may be especially vulnerable to disruption in aging-associated neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Humans; Lewy Bodies; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuronal Plasticity; Parkinson Disease; Signal Transduction; Synapses; Synucleins

Topics: alpha-Synuclein; Amyotrophic Lateral Sclerosis; Animals; Cysteine Endopeptidases; Humans; Lewy Bodies; Multienzyme Complexes; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; Proteasome Endopeptidase Complex; Synucleins; Ubiquitins

The synuclein gene family recently came into the spotlight, when one of its members, alpha-synuclein, was found to be mutated in several families with autosomal dominant Parkinson's disease (PD). A peptide of the alpha-synuclein protein had been characterized previously as a major component of amyloid plaques in brains of patients with Alzheimer's disease (AD). The mechanism by which this presynaptic protein is involved in the two most common neurodegenerative disorders, AD and PD, remains unclear. Remarkably, another member of this gene family, gamma-synuclein, has been shown to be overexpressed in breast carcinomas and may also be overexpressed in ovarian cancer. The possible involvement of the synuclein proteins in the etiology of common human diseases has raised exciting questions and is the subject of intense investigation. Details of the properties of any member of the synuclein family may provide useful information for understanding the characteristics and function of other family members. The present review offers a synopsis of the current state of knowledge of all synuclein family members in different species.

Topics: alpha-Synuclein; Alzheimer Disease; Amino Acid Sequence; Animals; Brain Chemistry; gamma-Synuclein; Gene Expression; Humans; Molecular Sequence Data; Neoplasms; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synucleins

Topics: alpha-Synuclein; Alzheimer Disease; Brain; Humans; Lewy Bodies; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Phosphoproteins; Synucleins; tau Proteins

Aureobasidium pullulans (black yeast) AFO-202 strain-produced beta glucan, Nichi Glucan, has been shown to improve the behavior and sleep pattern along with an increase in α-synuclein and melatonin in children with autism spectrum disorder (ASD).. In this randomized pilot clinical study, we have evaluated the gut microbiota of subjects with ASD after consumption of Nichi Glucan.. Eighteen subjects with ASD were randomly allocated: six subjects in the control group (Group 1): conventional treatment comprising remedial behavioral therapies and L-carnosine 500 mg per day, and 12 subjects (Group 2) underwent supplementation with Nichi Glucan 0.5 g twice daily along with the conventional treatment for 90 days.. Whole genome metagenome (WGM) sequencing of the stool samples at baseline and after intervention showed that among genera of relevance, the abundance of Enterobacteriaceae was decreased almost to zero in Group 2 after intervention, whereas it increased from 0.36% to 0.85% in Group 1. The abundance of Bacteroides increased in Group 1, whereas it decreased in Group 2. The abundance of Prevotella increased while the abundance of Lactobacillus decreased in both Group 1 and Group 2. Among species, a decrease was seen in Escherichia coli, Akkermansia muciniphila CAG:154, Blautia spp., Coprobacillus sp., and Clostridium bolteae CAG:59, with an increase of Faecalibacterium prausnitzii and Prevotella copri, which are both beneficial.. AFO-202 beta 1,3-1,6 glucan, in addition to balancing the gut microbiome in children with ASD and its role in effective control of curli-producing Enterobacteriaceae that leads to α-synuclein misfolding and accumulation, may have a prophylactic role in Parkinson's and Alzheimer's diseases as well.

Topics: alpha-Synuclein; Autism Spectrum Disorder; Gastrointestinal Microbiome; Glucans; Humans; Neurodegenerative Diseases

Easily accessible biomarkers for Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal dementia (FTD), and related neurodegenerative disorders are urgently needed in an aging society to assist early-stage diagnoses. In this study, we aimed to develop machine learning algorithms using the multiplex blood-based biomarkers to identify patients with different neurodegenerative diseases. Plasma samples (

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Cognitive Dysfunction; Female; Humans; Machine Learning; Male; Middle Aged; Neurodegenerative Diseases; Peptide Fragments; tau Proteins

To test the hypothesis that variability in SNCA Rep1, a polymorphic dinucleotide microsatellite in the promoter region of the gene encoding α-synuclein, modifies the association between head injury and Parkinson's disease (PD) risk.. Participants in the Farming and Movement Evaluation (FAME) and the Study of Environmental Association and Risk of Parkinsonism using Case-Control Historical Interviews (SEARCH), 2 independent case-control studies, were genotyped for Rep1 and interviewed regarding head injuries with loss of consciousness or concussion prior to Parkinson's disease (PD) diagnosis. Logistic regression modeling adjusted for potential confounding variables and tested interaction between Rep1 genotype and head injury.. Consistent with prior reports, relative to medium-length Rep1, short Rep1 genotype was associated with reduced PD risk (pooled odds ratio [OR], 0.7; 95% confidence interval [CI], 0.5-0.9), and long Rep1 with increased risk (pooled OR, 1.4; 95% CI, 0.95-2.2). Overall, head injury was not significantly associated with PD (pooled OR, 1.3; 95% CI, 0.9-1.8). However, head injury was strongly associated with PD in those with long Rep1 (FAME OR, 5.4; 95% CI, 1.5-19; SEARCH OR, 2.3; 95% CI, 0.6-9.2; pooled OR, 3.5; 95% CI 1.4-9.2, p-interaction = 0.02). Individuals with both head injury and long Rep1 were diagnosed 4.9 years earlier than those with neither risk factor (p = 0.03).. While head injury alone was not associated with PD risk, our data suggest head injury may initiate and/or accelerate neurodegeneration when levels of synuclein are high, as in those with Rep1 expansion. Given the high population frequency of head injury, independent verification of these results is essential.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Case-Control Studies; Cohort Studies; Craniocerebral Trauma; Female; Genetic Variation; Humans; Male; Microsatellite Repeats; Middle Aged; Neurodegenerative Diseases; Parkinson Disease; Prospective Studies

Ashwagandha-Withania somnifera (L.) Dunal, well known for its multipotent therapeutic properties has been used in Ayurveda for 3000 years. The plant with more than 50 active phytoconstituents is recognised for its anti-cancerous, anti-diabetic, anti-inflammatory, anti-microbial, and neurotherapeutic properties demonstrated in in vitro studies and chemically induced rodent models. Genetically targeted Parkinson's, Alzheimer's and other neurodegenerative disease models have been created in Drosophila and have been used to get mechanistic insight into the in vivo cellular events, and genetic pathways that underlie respective neurodegenerative condition. But hitherto, there aren't enough attempts made to capitalize the genetic potential of these disease models to validate the therapeutic efficacy of different reagents used in traditional medicine, in the context of specific disease-causing genetic mutations.. Drugs discovered using in vitro platforms might fail in several instances of clinical trials because of the genetic heterogeneity and variability in the physiological context found among the patients. Drosophila by virtue of its genetically regulated experimental potential forms an ideal in vivo model to validate the candidate reagents discovered in in vitro screens for their efficacy under specific genetic situations. Here we have used genetically induced α-synucleinopathy and tauopathy transgenic fly models to study the efficacy of Ashwagandha treatment, assessing cellular and behavioural parameters.. We have expressed the disease-causing human gene mutations in specific cell types of Drosophila using GAL4/UAS targeted expression system to create disease models. Human α-synuclein mutant (A30P) was expressed in dopaminergic neurons using Ddc-GAL4 driver strain to induce dopaminergic neurodegeneration and assayed for motor dysfunction. Human Tau. Lifespan assay shows that, Ashwagandha-root extract imparts an extended lifespan in male Drosophila flies which are intrinsically less stress resistant. Motor dysfunction caused due to human α-synuclein mutant protein expressed in dopaminergic neurons is greatly brought down. Further, Ashwagandha extract treatment significantly reduces Tau. We have carried out a multifaceted study which elucidates that Ashwagandha can serve as a comprehensive, phytotherapeutic formulation to combat neurodegeneration, targeting multiple causative genetically defective conditions.

Topics: alpha-Synuclein; Animals; Drosophila; Humans; Neurodegenerative Diseases; Plant Extracts; Tauopathies; Withania

Neurodegenerative diseases, being rapidly increasing disorders and the seventh leading cause of death worldwide, have been a great challenge for researchers, affecting cognition, motor activity and other body functioning due to neurodegeneration. Several neurodegenerative diseases are caused by aggregation of proteins which induce the alteration of neuronal function leading to cell death. These proteins are amyloid-β peptide, tau, α-synuclein, and mHTT, which cause Alzheimer's disease, Frontotemporal dementia, Corticobasal degeneration, Progressive supranuclear palsy, Parkinson's disease, Multiple system atrophy, Dementia with Lewy-body and Huntington's disease. Currently available treatments only reduce symptoms and increase life sustainability; however, they possess side effects and are ineffective in curing the diseases.. Literature survey of neurodegenerative diseases and immunotherapeutic approaches is used to evaluate their pharmacological effects and future endeavours.. A literature search was performed to find the relevant articles related to neurodegenerative diseases and immunotherapies. Clinical trials data were analysed from clinicaltrial.com.. According to the literature study, it was found that researchers have explored the effect of active and passive vaccines generated against amyloid-β, tau, α-synuclein and mHTT. Few clinical trials have shown severe side effects and terminated, despite that, few of them produced desirable effects for the treatment of AD and PD.. Several immunotherapeutic trials have shown promising outcomes against amyloid-β, tau and α-synuclein. In addition, various preclinical studies against mHTT and prion proteins are under scrutinization. These clinical outcomes indicate a promising role of immunotherapies against neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Immunotherapy; Neurodegenerative Diseases; Parkinson Disease; tau Proteins

Amyloid protein aggregation is widely involved in a number of neurodegenerative diseases for which novel therapeutic and diagnostic strategies are still needed. Owing to the complex and heterogeneous nature of the aggregated species responsible for toxicity in these disorders, a detailed characterization of the interaction of molecules of interest with the amyloid aggregates is a challenging endeavor. Here, we present the experimental and analytical steps of a protocol which combines dual-color fluorescence cross-correlation spectroscopy and dual-color single-particle fluorescence spectroscopy to quantify the binding affinity and stoichiometry of an inhibitor of α-synuclein amyloid aggregation. This approach allows studying the interaction in detail and through two independent analytical methods, thus yielding a remarkably robust tool that could be extended to investigating the interaction of molecules of interest to other pathogenic protein aggregates as well as multi-ligand/multi-receptor complexes.

Topics: alpha-Synuclein; Amyloid; Humans; Neurodegenerative Diseases; Protein Aggregates; Single Molecule Imaging; Spectrometry, Fluorescence

Topics: alpha-Synuclein; Animals; Astrocytes; Inflammation; Mesencephalon; Mice; Microglia; Neurodegenerative Diseases; Parkinson Disease

Neurodegenerative disorders are associated with different pathologies that often co-occur but cannot be measured specifically with in vivo methods.. Thirty-three brain hemispheres from donors with an Alzheimer's disease (AD) spectrum diagnosis underwent T2-weighted magnetic resonance imaging (MRI). Gray matter thickness was paired with histopathology from the closest anatomic region in the contralateral hemisphere.. Partial Spearman correlation of phosphorylated tau and cortical thickness with TAR DNA-binding protein 43 (TDP-43) and α-synuclein scores, age, sex, and postmortem interval as covariates showed significant relationships in entorhinal and primary visual cortices, temporal pole, and insular and posterior cingulate gyri. Linear models including Braak stages, TDP-43 and α-synuclein scores, age, sex, and postmortem interval showed significant correlation between Braak stage and thickness in the parahippocampal gyrus, entorhinal cortex, and Broadman area 35.. We demonstrated an association of measures of AD pathology with tissue loss in several AD regions despite a limited range of pathology in these cases.. Neurodegenerative disorders are associated with co-occurring pathologies that cannot be measured specifically with in vivo methods. Identification of the topographic patterns of these pathologies in structural magnetic resonance imaging (MRI) may provide probabilistic biomarkers. We demonstrated the correlation of the specific patterns of tissue loss from ex vivo brain MRI with underlying pathologies detected in postmortem brain hemispheres in patients with Alzheimer's disease (AD) spectrum disorders. The results provide insight into the interpretation of in vivo structural MRI studies in patients with AD spectrum disorders.

Topics: alpha-Synuclein; Alzheimer Disease; DNA-Binding Proteins; Humans; Magnetic Resonance Imaging; Neurodegenerative Diseases; tau Proteins

Parkinson's disease (PD), a neurodegenerative disease affecting dopaminergic (DA) neurons, is characterized by decline of motor function and cognition. Dopaminergic cell loss is associated with accumulation of toxic alpha synuclein aggregates. As DA neuron death occurs late in the disease, therapeutics that block the spread of alpha synuclein may offer functional benefit and delay disease progression. To test this hypothesis, we generated antibodies to the C terminal region of synuclein with high nanomolar affinity and characterized them in in vitro and in vivo models of spread. Interestingly, we found that only antibodies with high affinity to the distal most portion of the C-terminus robustly reduced uptake of alpha synuclein preformed fibrils (PFF) and accumulation of phospho (S129) alpha synuclein in cell culture. Additionally, the antibody treatment blocked the spread of phospho (S129) alpha synuclein associated-pathology in a mouse model of synucleinopathy. Blockade of neuronal PFF uptake by different antibodies was more predictive of in vivo activity than their binding potency to monomeric or oligomeric forms of alpha synuclein. These data demonstrate that antibodies directed to the C-terminus of the alpha synuclein have differential effects on target engagement and efficacy. Furthermore, our data provides additional support for the development of alpha synuclein antibodies as a therapeutic strategy for PD patients.

Topics: alpha-Synuclein; Animals; Dopaminergic Neurons; Mice; Neurodegenerative Diseases; Parkinson Disease; Synucleinopathies

Protein aggregates are considered key pathological features in neurodegenerative diseases (NDs). The induction of autophagy can effectively promote the clearance of ND-related misfolded proteins.. In this study, we aimed to screen natural autophagy enhancers from traditional Chinese medicines (TCMs) presenting potent neuroprotective potential in multiple ND models.. The autophagy enhancers were broadly screened in our established herbal extract library using the transgenic Caenorhabditis elegans (C. elegans) DA2123 strain. The neuroprotective effects of the identified autophagy enhancers were evaluated in multiple C. elegans ND models by measuring Aβ-, Tau-, α-synuclein-, and polyQ40-induced pathologies. In addition, PC-12 cells and 3 × Tg-AD mice were employed to further validate the neuroprotective ability of the identified autophagy enhancers, both in vitro and in vivo. Furthermore, RNAi bacteria and autophagy inhibitors were used to evaluate whether the observed effects of the identified autophagy enhancers were mediated by the autophagy-activated pathway.. The ethanol extract of Folium Hibisci Mutabilis (FHME) was found to significantly increase GFP::LGG-1-positive puncta in the DA2123 worms. FHME treatment markedly inhibited Aβ, α-synuclein, and polyQ40, as well as prolonging the lifespan and improving the behaviors of C. elegans, while siRNA targeting four key autophagy genes partly abrogated the protective roles of FHME in C. elegans. Additionally, FHME decreased the expression of AD-related proteins and restored cell viability in PC-12 cells, which were canceled by cotreatment with 3-methyladenine (3-MA) or bafilomycin A1 (Baf). Moreover, FHME ameliorated AD-like cognitive impairment and pathology, as well as activating autophagy in 3 × Tg-AD mice.. FHME was successfully screened from our natural product library as a potent autophagy enhancer that exhibits a neuroprotective effect in multiple ND models across species through the induction of autophagy. These findings offer a new and reliable strategy for screening autophagy inducers, as well as providing evidence that FHME may serve as a possible therapeutic agent for NDs.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Animals, Genetically Modified; Autophagy; Caenorhabditis elegans; Mice; Neurodegenerative Diseases; Neuroprotective Agents

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

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

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

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

Cell-to-cell transmission and subsequent amplification of pathological proteins promote neurodegenerative disease progression. Most research on this has focused on pathological protein seeds, but how their normal counterparts, which are converted to pathological forms during transmission, regulate transmission is less understood. Here we show in cultured cells that phosphorylation of soluble, nonpathological α-synuclein (α-Syn) at previously identified sites dramatically affects the amplification of pathological α-Syn, which underlies Parkinson's disease and other α-synucleinopathies, in a conformation- and phosphorylation site-specific manner. We performed LC-MS/MS analyses on soluble α-Syn purified from Parkinson's disease and other α-synucleinopathies, identifying many new α-Syn post-translational modifications (PTMs). In addition to phosphorylation, acetylation of soluble α-Syn also modified pathological α-Syn transmission in a site- and conformation-specific manner. Moreover, phosphorylation of soluble α-Syn could modulate the seeding properties of pathological α-Syn. Our study represents the first systematic analysis how of soluble α-Syn PTMs affect the spreading and amplification of pathological α-Syn, which may affect disease progression.

Topics: alpha-Synuclein; Chromatography, Liquid; Humans; Neurodegenerative Diseases; Parkinson Disease; Protein Processing, Post-Translational; Synucleinopathies; Tandem Mass Spectrometry

The pathological hallmark of many neurodegenerative diseases is the accumulation of characteristic proteinaceous aggregates. Parkinson's disease and dementia with Lewy bodies can be characterized as synucleinopathies due to the abnormal accumulation of the protein alpha-synuclein (α-Syn). Studies have shown amyloidogenic proteins such as α-Syn and tau can exist as polymorphic aggregates, a theory widely studied mostly in their fibrillar morphology. It is now well understood that an intermediate state of aggregates, oligomers, are the most toxic species. We have shown α-Syn, when modified by different physiological inducers, result in distinct oligomeric conformations of α-Syn. Polymorphic α-Syn oligomers exhibit distinct properties such as aggregate size, conformation, and differentially interact with tau. In this study, we confirm α-Syn oligomeric polymorphs furthermore using in-house novel α-Syn toxic conformation monoclonal antibodies (SynTCs). It is unclear the biological relevance of α-Syn oligomeric polymorphisms. Utilizing a combination of biochemical, biophysical, and cell-based assays, we characterize α-Syn oligomeric polymorphs. We found α-Syn oligomeric polymorphs exhibit distinct immunoreactivity and SynTCs exhibit differential selectivity and binding affinity for α-Syn species. Isothermal titration calorimetry experiments suggest distinct α-Syn:SynTC binding enthalpies in a species-specific manner. Additionally, we found SynTCs differentially reduce α-Syn oligomeric polymorph-mediated neurotoxicity and propagation in primary cortical neurons in a polymorph-specific manner. These studies demonstrate the biological significance of polymorphic α-Syn oligomers along with the importance of polymorph-specific antibodies that target toxic α-Syn aggregates. Monoclonal antibodies that can target the conformational heterogeneity of α-Syn oligomeric species and reduce their mediated toxicity have promising immunotherapeutic potential.

Topics: alpha-Synuclein; Antibodies, Monoclonal; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease

The environment, containing pollutants, toxins, and transition metals (copper, iron, manganese, and zinc), plays a critical role in neurodegenerative disease development. Copper occupational exposure increases Parkinson's disease (PD) risk. Previously, we determined the mechanisms by which copper induces dopaminergic cell death in vitro. The copper transporter protein 1 (Ctr1) overexpression led to intracellular glutathione depletion potentiating caspase-3 mediated cell death; oxidative stress was primarily cytosolic, and Nrf2 was upregulated mediating an antioxidant response; and protein ubiquitination, AMPK-Ulk1 signaling, p62, and Atg5-dependent autophagy were increased as a protective mechanism. However, the effect of chronic copper exposure on the neurodegenerative process has not been explored in vivo. We aimed to elucidate whether prolonged copper treatment reproduces PD features and mechanisms during aging. Throughout 40 weeks, C57BL/6J male mice were treated with copper at 0, 100, 250, and 500 ppm in the drinking water. Chronic copper exposure altered motor function and induced dopaminergic neuronal loss, astrocytosis, and microgliosis in a dose-dependent manner. α-Synuclein accumulation and aggregation were increased in response to copper, and the proteasome and autophagy alterations, previously observed in vitro, were confirmed in vivo, where protein ubiquitination, AMPK phosphorylation, and the autophagy marker LC3-II were also increased by copper exposure. Finally, nitrosative stress was induced by copper in a concentration-dependent fashion, as evidenced by increased protein nitration. To our knowledge, this is the first study combining chronic copper exposure and aging, which may represent an in vivo model of non-genetic PD and help to assess potential prophylactic and therapeutic approaches. DATA AVAILABILITY: The data underlying this article are available in the article.

Topics: Aging; alpha-Synuclein; AMP-Activated Protein Kinases; Animals; Copper; Dopaminergic Neurons; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Parkinson Disease

A-synuclein (α-syn) is a protein associated with the pathogenesis of Parkinson's disease (PD), a neurodegenerative disease with no effective treatment. Therefore, there has been a strong drive to clarify the pathology of PD associated with α-syn. Several mechanisms have been proposed to unravel the pathological cascade of this disease, and most of them share a particular similarity: cell-to-cell communication through exosomes (EXO). Here, we show that tumor necrosis factor receptor superfamily member 10B (TNFRSF10B) promotes the secretion of α-syn-containing EXO by microglia, resulting in motor dysfunction in PD. Upregulation of TNFRSF10B predicted severer condition in PD patients. In response to α-syn preformed fibrils (PFF), the expression of TNFRSF10B was increased in microglia. PFF-treated microglia exhibited a pro-inflammatory phenotype and caused neuronal damage by secreting α-syn-containing EXO. TNFRSF10B downregulation in microglia inhibited the secretion of α-syn-containing EXO and the release of pro-inflammatory factors, and ameliorated neuronal injury. PFF induced motor dysfunction in mice, which was ameliorated by inhibiting TNFRSF10B to suppress microglia-mediated α-syn communication or by directly depleting microglia. Taken together, these results indicate that TNFRSF10B promotes neuronal injury and motor dysfunction by delivery of α-syn-containing EXO and highlight the TNFRSF10B knockdown as a potential therapeutic target in PD.

Topics: alpha-Synuclein; Animals; Exosomes; Humans; Mice; Microglia; Neurodegenerative Diseases; Neurons; Parkinson Disease; Receptors, TNF-Related Apoptosis-Inducing Ligand

Parkinson's disease (PD) is the second most common neurodegenerative disease but still lacks a preclinical strategy to identify it. The diagnostic value of intestinal mucosal α-synuclein (αSyn) in PD has not drawn a uniform conclusion. The relationship between the alteration of intestinal mucosal αSyn expression and mucosal microbiota is unclear. Nineteen PD patients and twenty-two healthy controls were enrolled in our study from whom were collected, using gastrointestinal endoscopes, duodenal and sigmoid mucosal samples for biopsy. Multiplex immunohistochemistry was performed to detect total, phosphorylate, and oligomer α-synuclein. Next-generation 16S rRNA amplicon sequencing was applied for taxonomic analysis. The results implied that oligomer α-synuclein (OSyn) in sigmoid mucosa of PD patients was transferred from the intestinal epithelial cell membrane to the cytoplasm, acinar lumen, and stroma. Its distribution feature was significantly different between the two groups, especially the ratio of OSyn/αSyn. The microbiota composition in mucosa also differed. The relative abundances of Kiloniellales, Flavobacteriaceae, and CAG56 were lower, while those of Proteobacteria, Gammaproteobacteria, Burkholderiales, Burkholdriaceae, Oxalobacteraceae, Ralstonia, Massilla, and Lactoccus were higher in duodenal mucosa of PD patients. The relative abundances of Thermoactinomycetales and Thermoactinomycetaceae were lower, while those of Prevotellaceae and Bifidobacterium longum were higher in patients' sigmoid mucosa. Further, the OSyn/αSyn level was positively correlated with the relative abundances of Proteobacteria, Gammaproteobacteria, Burkholderiales, Pseudomonadales, Burkholderiaceae, and Ralstonia in the duodenal mucosa, while it was negatively correlated with the Chao1 index and observed operational taxonomic units of microbiota in sigmoid mucosa. The intestinal mucosal microbiota composition of PD patients altered with the relative abundances of proinflammatory bacteria in the duodenal mucosa increased. The ratio of the OSyn/αSyn level in the sigmoid mucosa indicated a potential diagnostic value for PD, which also correlated with mucosal microbiota diversity and composition. KEY POINTS: • The distribution of OSyn in sigmoid mucosa differed between PD patients and healthy controls. • Significant alterations in the microbiome were found in PD patients' gut mucosa. • OSyn/αSyn level in sigmoid mucosa indicated a potential diagnostic value for PD.

Topics: alpha-Synuclein; Humans; Intestinal Mucosa; Microbiota; Neurodegenerative Diseases; Parkinson Disease; RNA, Ribosomal, 16S

Tau aggregate-bearing lesions are pathological markers and potential mediators of tauopathic neurodegenerative diseases, including Alzheimer's disease. The molecular chaperone DJ-1 colocalizes with tau pathology in these disorders, but it has been unclear what functional link exists between them. In this study, we examined the consequences of tau/DJ-1 interaction as isolated proteins

Topics: alpha-Synuclein; Humans; Molecular Chaperones; Neurodegenerative Diseases; Parkinson Disease; Protein Deglycase DJ-1; tau Proteins

The aberrant deposition of α-synuclein (α-Syn) protein into the intracellular neuronal aggregates termed Lewy bodies and Lewy neurites characterizes the devastating neurodegenerative condition known as Parkinson's disease (PD). The disruption of pre-existing disease-relevant α-Syn fibrils is recognized as a viable therapeutic approach for PD. Ellagic acid (EA), a natural polyphenolic compound, is experimentally proven as a potential candidate that prevents or reverses the α-Syn fibrillization process. However, the detailed inhibitory mechanism of EA against the destabilization of α-Syn fibril remains largely unclear. In this work, the influence of EA on α-Syn fibril and its putative binding mechanism were explored using molecular dynamics (MD) simulations. EA interacted primarily with the non-amyloid-β component (NAC) of α-Syn fibril, disrupting its β-sheet content and thereby increasing the coil content. The E46-K80 salt bridge, critical for the stability of Greek-key-like α-Syn fibril, was disrupted in the presence of EA. The binding free energy analysis using the MM-PBSA method demonstrates the favourable binding of EA to α-Syn fibril (Δ

Topics: alpha-Synuclein; Ellagic Acid; Humans; Molecular Dynamics Simulation; Neurodegenerative Diseases; Parkinson Disease

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

The molecular mechanisms underlying the pathogenesis of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease (PD), and Huntington's disease remain enigmatic, resulting in an unmet need for therapeutics development. Here, we suggest that filbertone, a key flavor compound found in the fruits of hazel trees of the genus Corylus, can ameliorate PD via lowering the abundance of aggregated α-synuclein. We previously reported that inhibition of hypothalamic inflammation by filbertone is mediated by suppression of nuclear factor kappa-B. Here, we report that filbertone activates PERK through mitochondrial reactive oxygen species production, resulting in the increased nuclear translocation of transcription factor-EB in SH-SY5Y human neuroblastoma cells. TFEB activation by filbertone promotes the autophagy-lysosomal pathway, which in turn alleviates the accumulation of α-synuclein. We also demonstrate that filbertone prevented the loss of dopaminergic neurons in the substantia nigra and striatum of mice on high-fat diet. Filbertone treatment also reduced high-fat diet-induced α-synuclein accumulation through upregulation of the autophagy-lysosomal pathway. In addition, filbertone improved behavioral abnormalities (i.e., latency time to fall and decrease of running distance) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD murine model. In conclusion, filbertone may show promise as a potential therapeutic for neurodegenerative disease.

Topics: alpha-Synuclein; Animals; Autophagy; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Dopaminergic Neurons; Humans; Lysosomes; Mice; Neuroblastoma; Neurodegenerative Diseases; Parkinson Disease; Reactive Oxygen Species

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

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

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

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

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

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

Alpha-Synuclein (α-Synuclein) is a 140 amino acid protein implicated in neurodegenerative disorders known as synucleinopathies, where it accumulates in proteinaceous inclusions in the brain. The normal physiological function of α-Synuclein remains obscure, as it exists in several non-neuronal cells in which its function has not been studied. Given the tremendous interest in studying α-Synuclein, and the existing limitations in the production of modified forms of the protein, we developed a method for the chemical synthesis of α-Synuclein by combining peptide fragment synthesis via automated microwave-assisted solid-phase peptide synthesis and ligation strategies. Our synthetic pathway enables the synthesis of protein variants of interest, carrying either mutations or posttranslational modifications, for further investigations of the effects on the structure and aggregation behavior of the protein. Ultimately, our study forms the foundation for future syntheses and studies of other custom-made α-Synuclein variants with a single or several modifications, as necessary.

Topics: alpha-Synuclein; Brain; Humans; Neurodegenerative Diseases; Protein Processing, Post-Translational; Solid-Phase Synthesis Techniques

There is a lack of effective diagnostic biomarkers for neurodegenerative disorders (NDDs). Here, we established gene expression profiles for diagnosing Alzheimer's disease (AD), Parkinson's disease (PD), and vascular (VaD)/mixed dementia. Patients with AD had decreased APOE, PSEN1, and ABCA7 mRNA expression. Subjects with VaD/mixed dementia had 98% higher PICALM mRNA levels, but 75% lower ABCA7 mRNA expression than healthy individuals. Patients with PD and PD-related disorders showed increased SNCA mRNA levels. There were no differences in mRNA expression for OPRK1, NTRK2, and LRRK2 between healthy subjects and NDD patients. APOE mRNA expression had high diagnostic accuracy for AD, and moderate accuracy for PD and VaD/mixed dementia. PSEN1 mRNA expression showed promising accuracy for AD. PICALM mRNA expression was less accurate as a biomarker for AD. ABCA7 and SNCA mRNA expression showed high-to-excellent diagnostic accuracy for AD and PD, and moderate-to-high accuracy for VaD/mixed dementia. The APOE E4 allele reduced APOE expression in patients with different APOE genotypes. There was no association between PSEN1, PICALM, ABCA7, and SNCA gene polymorphisms and expression. Our study suggests that gene expression analysis has diagnostic value for NDDs and provides a liquid biopsy alternative to current diagnostic methods.

Topics: alpha-Synuclein; Alzheimer Disease; Apolipoproteins E; Gene Expression Profiling; Humans; Neurodegenerative Diseases; Parkinson Disease; Polymorphism, Genetic

Parkinson's disease (PD) is a very common neurodegenerative disease that adversely affects the physical and mental health of many patients, but there is currently no effective treatment.. To this end, this study focused on investigating the potential mechanisms leading to dopaminergic neuronal apoptosis in PD.. Rotenone induces damage in dopaminergic neuronal MN9D cells. Apoptosis was detected by flow cytometry, and the expression of apoptosis-related proteins was detected by western blot. RT-qPCR was used to detect the expression of MALAT1 and miR-23b-3p. The expression of. The expression of MALAT1 and. MALAT1 can promote

Topics: alpha-Synuclein; Animals; Apoptosis; Autophagy; Dopaminergic Neurons; Humans; Mice; Microglia; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; RNA, Long Noncoding

The accumulation and aggregation of

Topics: alpha-Synuclein; Humans; Maneb; Neurodegenerative Diseases; Neurotoxicity Syndromes; NF-E2-Related Factor 2; Oxidation-Reduction; Reactive Oxygen Species

Autosomal dominant mutations in α-synuclein, TDP-43 and tau are thought to predispose to neurodegeneration by enhancing protein aggregation. While a subset of α-synuclein, TDP-43 and tau mutations has been shown to increase the structural propensity of these proteins toward self-association, rates of aggregation are also highly dependent on protein steady state concentrations, which are in large part regulated by their rates of lysosomal degradation. Previous studies have shown that lysosomal proteases operate precisely and not indiscriminately, cleaving their substrates at very specific linear amino acid sequences. With this knowledge, we hypothesized that certain coding mutations in α-synuclein, TDP-43 and tau may lead to increased protein steady state concentrations and eventual aggregation by an alternative mechanism, that is, through disrupting lysosomal protease cleavage recognition motifs and subsequently conferring protease resistance to these proteins.. To test this possibility, we first generated comprehensive proteolysis maps containing all of the potential lysosomal protease cleavage sites for α-synuclein, TDP-43 and tau. In silico analyses of these maps indicated that certain mutations would diminish cathepsin cleavage, a prediction we confirmed utilizing in vitro protease assays. We then validated these findings in cell models and induced neurons, demonstrating that mutant forms of α-synuclein, TDP-43 and tau are degraded less efficiently than wild type despite being imported into lysosomes at similar rates.. Together, this study provides evidence that pathogenic mutations in the N-terminal domain of α-synuclein (G51D, A53T), low complexity domain of TDP-43 (A315T, Q331K, M337V) and R1 and R2 domains of tau (K257T, N279K, S305N) directly impair their own lysosomal degradation, altering protein homeostasis and increasing cellular protein concentrations by extending the degradation half-lives of these proteins. These results also point to novel, shared, alternative mechanism by which different forms of neurodegeneration, including synucleinopathies, TDP-43 proteinopathies and tauopathies, may arise. Importantly, they also provide a roadmap for how the upregulation of particular lysosomal proteases could be targeted as potential therapeutics for human neurodegenerative disease.

Topics: alpha-Synuclein; DNA-Binding Proteins; Half-Life; Humans; Lysosomes; Mutation; Neurodegenerative Diseases; Peptide Hydrolases; tau Proteins

Tau neurofibrillary tangles are a hallmark of Alzheimer's disease neuropathological change. However, it remains largely unclear how distinctive Alzheimer's disease tau seeds (i.e. 3R/4R) correlate with histological indicators of tau accumulation. Furthermore, AD tau co-pathology is thought to influence features and progression of other neurodegenerative diseases including Lewy body disease; yet measurements of different types of tau seeds in the setting of such diseases is an unmet need. Here, we use tau real-time quaking-induced conversion (RT-QuIC) assays to selectively quantitate 3R/4R tau seeds in the frontal lobe which accumulates histologically identifiable tau pathology at late disease stages of AD neuropathologic change. Seed quantitation across a spectrum of neurodegenerative disease cases and controls indicated tau seeding activity can be detected well before accompanying histopathological indication of tau deposits, and even prior to the earliest evidence of Alzheimer's-related tau accumulation anywhere in the brain. In later stages of AD, 3R/4R tau RT-QuIC measures correlated with immunohistochemical tau burden. In addition, Alzheimer's tau seeds occur in the vast majority of cases evaluated here inclusive of primary synucleinopathies, frontotemporal lobar degeneration and even controls albeit at multi-log lower levels than Alzheimer's cases. α-synuclein seeding activity confirmed synucleinopathy cases and further indicated the co-occurrence of α-synuclein seeds in some Alzheimer's disease and primary tauopathy cases. Our analysis indicates that 3R/4R tau seeds in the mid-frontal lobe correlate with the overall Braak stage and Alzheimer's disease neuropathologic change, supporting the quantitative predictive value of tau RT-QuIC assays. Our data also indicate 3R/4R tau seeds are elevated in females compared to males at high (≥ IV) Braak stages. This study suggests 3R/4R tau seeds are widespread even prior to the earliest stages of Alzheimer's disease changes, including in normal, and even young individuals, with prevalence across multiple neurodegenerative diseases to further define disease subtypes.

Topics: alpha-Synuclein; Alzheimer Disease; Female; Humans; Male; Neurodegenerative Diseases; Synucleinopathies; tau Proteins; Tauopathies

Topics: alpha-Synuclein; Animals; Autophagy; Dopaminergic Neurons; Female; Male; Mice; Microglia; Neurodegenerative Diseases; Neuroinflammatory Diseases; NF-kappa B; Parkinson Disease; Rotenone

Parkinson's disease (PD) is a multifactorial neurodegenerative disease characterized by the loss of dopaminergic neurons in the midbrain. In the prodromal phase several autonomic symptoms including orthostatic hypotension and constipation are correlated with increased α-synuclein pathology in peripheral tissues. It is currently accepted that some idiopathic PD cases may start in the gut (body-first PD) with accumulation of pathological α-synuclein in enteric neurons that may subsequently propagate caudo-rostrally to the central nervous system. In addition to the already-established regulation of synaptic vesicle trafficking, α-synuclein also seems to play a role in neuronal innate immunity after infection. Our goal was to understand if seeding the gut with the foodborne pathogen Listeria monocytogenes by oral gavage would impact gut immunity and eventually the central nervous system. Our results demonstrate that L. monocytogenes infection induced oligomerization of α-synuclein in the ileum, along with a pronounced pro-inflammatory local and systemic response that ultimately culminated in neuronal mitochondria dysfunction. We propose that, having evolved from ancestral endosymbiotic bacteria, mitochondria may be directly targeted by virulence factors of intracellular pathogens, and that mitochondrial dysfunction and fragmentation resulting also from the activation of the innate immune system at the gut level, trigger innate immune responses in midbrain neurons, which include α-synuclein oligomerization and neuroinflammation, all of which hallmarks of PD.

Topics: alpha-Synuclein; Dopaminergic Neurons; Humans; Mitochondria; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by bradykinesia, rigidity, and tremor. However, familial PD caused by single-gene mutations remain relatively rare. Herein, we described a Chinese family affected by PD, which associated with a missense heterozygous glucocerebrosidase 1 (GBA1) mutation (c.231C > G). Clinical data on the proband and her family members were collected. Brain MRI showed no difference between affected and unaffected family members. Whole-exome sequencing (WES) was performed to identify the pathogenic mutation. WES revealed that the proband carried a missense mutation (c.231C > G) in GBA1 gene, which was considered to be associated with PD in this family. Sanger sequencing and co-segregation analyses were used to validate the mutation. Bioinformatics analysis indicated that the mutation was predicted to be damaging. In vitro functional analyses were performed to investigated the mutant gene. A decrease in mRNA and protein expression was observed in HEK293T cells transfected with mutant plasmids. The GBA1 c.231C > G mutation caused a decreased GBA1 concentration and enzyme activity. In conclusion, a loss of function mutation (c.231C > G) in GBA1 was identified in a Chinese PD family and was confirmed to be pathogenic through functional studies. This study help the family members understand the disease progression and provide a new example for studying the pathogenesis of GBA1-associated Parkinson disease.

Topics: alpha-Synuclein; Female; Glucosylceramidase; HEK293 Cells; Humans; Mutation; Neurodegenerative Diseases; Parkinson Disease

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease; Phenylethyl Alcohol

Seed amplification assays (SAA) are the first credible molecular assay for Parkinson's disease (PD). However, the value of SAA to support the clinicians' initial diagnosis of PD is not clear. In our study, we analyzed cerebrospinal fluid samples from 121 PD patients recruited through population screening methods and taken within a median delay of 38 days from diagnosis and 51 normal controls without neurodegenerative disease. SAA yielded a sensitivity of 82.6% (95% CI, 74.7% - 88.9%) and specificity of 88.2% (95% CI, 76.1% - 95.6%). These results highlight the potential of SAA to support the initial diagnosis of PD in clinical practice and research.

Topics: alpha-Synuclein; Alzheimer Disease; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease

Parkinson's is the second most common neurodegenerative disease, with the number of individuals susceptible due to increase as a result of increasing life expectancy and a growing worldwide population. However, despite the number of individuals affected, all current treatments for PD are symptomatic-they alleviate symptoms, but do not slow disease progression. A major reason for the lack of disease-modifying treatments is that there are currently no methods to diagnose individuals during the earliest stages of the disease, nor are there any methods to monitor disease progression at a biochemical level. Herein, we have designed and evaluated a peptide-based probe to monitor αS aggregation, with a particular focus on the earliest stages of the aggregation process and the formation of oligomers. We have identified the peptide-probe K1 as being suitable for further development to be applied to number of applications including: inhibition of αS aggregation; as a probe to monitor αS aggregation, particularly at the earliest stages before Thioflavin-T is active; and a method to detect early-oligomers. With further development and in vivo validation, we anticipate this probe could be used for the early diagnosis of PD, a method to evaluate the effectiveness of potential therapeutics, and as a tool to help in the understanding of the onset and development of PD.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Peptides

Synucleinopathies are characterized by the accumulation of α-synuclein (α-Syn) aggregates in the brain. Positron emission tomography (PET) imaging of synucleinopathies requires radiopharmaceuticals that selectively bind α-Syn deposits. We report the identification of a brain permeable and rapid washout PET tracer [

Topics: alpha-Synuclein; Animals; Brain; Humans; Neurodegenerative Diseases; Positron-Emission Tomography; Synucleinopathies

Recent advanced studies in neurodegenerative diseases have revealed several links connecting autophagy and neurodegeneration. Autophagy is the major cellular degradation process for the removal of toxic protein aggregates responsible for neurodegenerative diseases. More than 30 autophagy-related proteins have been identified as directly participating in the autophagy process. Proteins regulating the process of autophagy are much more numerous and unknown. To address this, in our present study, we identified a novel regulator (ARL6IP5) of neuronal autophagy and showed that the level of ARL6IP5 decreases in the brain with age and in Parkinson's disease in mice and humans. Moreover, a cellular model of PD (Wild type and A53T mutant α-synuclein overexpression) has also shown decreased levels of ARL6IP5. ARL6IP5 overexpression reduces α-synuclein aggregate burden and improves cell survival in an A53T model of Parkinson's disease. Interestingly, detailed mechanistic studies revealed that ARL6IP5 is an autophagy inducer. ARL6IP5 enhances Rab1-dependent autophagosome initiation and elongation by stabilizing free ATG12. We report for the first time that α-synuclein downregulates ARL6IP5 to inhibit autophagy-dependent clearance of toxic aggregates that exacerbate neurodegeneration.

Topics: alpha-Synuclein; Animals; Autophagy; Autophagy-Related Protein 12; Cell Line; Heat-Shock Proteins; Humans; Membrane Transport Proteins; Mice; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting millions of people worldwide. Despite considerable efforts, the underlying pathological mechanisms remain elusive, and yet, no treatment has been developed to efficiently reverse or modify disease progression. Thus, new experimental models are required to provide insights into the pathology of PD. Small-molecule neural precursor cells (smNPCs) are ideal for the study of neurodegenerative disorders due to their neural identity and stem cell properties. Cytoplasmic aggregates of α-synuclein (αSyn) are considered a hallmark of PD and a point mutation in the gene encoding p.A53T is responsible for a familial PD form with earlier and robust symptom onset. In order to study the cellular pathology of PD, we genetically modified smNPCs to inducibly overexpress EYFP-SNCA A53T. This cellular model was biochemically characterized, while dysregulated biological pathways and key regulators of PD pathology were identified by computational analyses. Our study indicates three novel genes, UBA52, PIP5K1A, and RPS2, which may mediate PD cellular pathology.

Topics: alpha-Synuclein; Humans; Neural Stem Cells; Neurodegenerative Diseases; Neurons; Parkinson Disease

The second most prevalent neurodegenerative disease, Parkinson's disease (PD), is caused by the accumulation and deposition of fibrillar aggregates of the α-Syn into the Lewy bodies. To create a potent pharmacological candidate to destabilize the preformed α-Syn fibril, it is important to understand the precise molecular mechanism underlying the destabilization of the α-Syn fibril. Through molecular dynamics simulations and experiments, we have examined the molecular mechanisms causing the destabilization and suppression of a newly discovered α-Syn fibril with a Greek-key-like shape and an aggregation prone state (APS) of α-Syn in the presence and absence of various Flvs. According to MD simulation and experimental evidence, morin, quercetin, and myricetin are the Flvs, most capable of destabilizing the fibrils and converting them into amorphous aggregates. Compared to galangin and kaempferol, they have more hydroxyl groups and form more hydrogen bonds with fibrils.The processes by which morin and myricetin prevent new fibril production from APS and destabilize the fibrils are different. According to linear interaction energy analysis, van der Waals interaction predominates with morin, and electrostatic interaction dominates with myricetin. Our MD simulation and experimental findings provide mechanistic insights into how Flvs destabilize α-Syn fibrils and change their morphology, opening the door to developing structure-based drugs for treating Parkinson's disease.

Topics: alpha-Synuclein; Flavonoids; Humans; Molecular Dynamics Simulation; Neurodegenerative Diseases; Parkinson Disease

Tauopathies and synucleinopathies are characterized by the aggregation of Tau and α-synuclein (AS) into amyloid structures, respectively. Individuals with these neuropathies have an elevated risk of developing subsequent neurodegenerative or comorbid disorders. Intriguingly, post-mortem brain examinations have revealed co-localization of Tau and AS aggregates, suggesting a synergistic pathological relationship with an adverse prognosis. The role of liquid-liquid phase separation (LLPS) in the development of neurodegenerative diseases is currently receiving significant attention, as it can contribute to the aggregation and co-deposition of amyloidogenic proteins. In this study, we investigated the phase separation behavior of Tau and AS under various insults, some of which are implicated in disease progression. Our findings demonstrate the formation of heterotypic droplets composed of Tau and AS at physiologically relevant mole ratios that mimic neurons' soma and terminal buttons. Importantly, these heterotypic droplets exhibit increased resistance to electrostatic screening compared to homotypic condensates. Moreover, we observed that biologically relevant biomolecules, known to be dysregulated in disease, exert different effects on these droplets. Additionally, we provide evidence that phase separation itself influences the amyloid aggregation of Tau and AS, underscoring the significance of this process in the development of aggregopathies.

Topics: alpha-Synuclein; Amyloid; Amyloidogenic Proteins; Humans; Neurodegenerative Diseases; tau Proteins

Hsp104 is an AAA+ protein disaggregase that solubilizes and reactivates proteins trapped in aggregated states. We have engineered potentiated Hsp104 variants to mitigate toxic misfolding of α-synuclein, TDP-43, and FUS implicated in fatal neurodegenerative disorders. Though potent disaggregases, these enhanced Hsp104 variants lack substrate specificity and can have unfavorable off-target effects. Here, to lessen off-target effects, we engineer substrate-specific Hsp104 variants. By altering Hsp104 pore loops that engage substrate, we disambiguate Hsp104 variants that selectively suppress α-synuclein toxicity but not TDP-43 or FUS toxicity. Remarkably, α-synuclein-specific Hsp104 variants emerge that mitigate α-synuclein toxicity via distinct ATPase-dependent mechanisms involving α-synuclein disaggregation or detoxification of soluble α-synuclein conformers. Importantly, both types of α-synuclein-specific Hsp104 variant reduce dopaminergic neurodegeneration in a C. elegans model of Parkinson's disease more effectively than non-specific variants. We suggest that increasing the substrate specificity of enhanced disaggregases could be applied broadly to tailor therapeutics for neurodegenerative disease.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Heat-Shock Proteins; Humans; Neurodegenerative Diseases; Saccharomyces cerevisiae Proteins

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

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

Parkinson's disease (PD) is a neurodegenerative disorder that mainly affects the elder population, and its etiology is enigmatic. Both environmental risks and genetics may influence the development of PD. Excess copper causes neurotoxicity and accelerates the progression of neurodegenerative diseases. However, the underlying mechanisms of copper-induced neurotoxicity remain controversial. In this study, A53T transgenic α-synuclein (A53T) mice and their matching wild-type (WT) mice were treated with a low dose of copper (0.13 ppm copper chlorinated drinking water, equivalent to the copper exposure of human daily copper intake dose) for 4 months, and copper poisoning was performed on human A53T mutant SHSY5Y cells overexpressed with α-synuclein (dose of 1/4 IC50), to test the effects of copper exposure on the body. The results of the open field test showed that the moto function of Cu-treated mice was impaired. Proteomics revealed changes in neurodevelopment, transport function, and mitochondrial membrane-related function in Cu-treated WT mice, which were associated with reduced expression of mitochondrial complex (NDUFA10, ATP5A), dopamine neurons (TH), and dopamine transporter (DAT). Mitochondrial function, nervous system development, synaptic function, and immune response were altered in Cu-treated A53T mice. These changes were associated with increased mitochondrial splitting protein (Drp1), decreased mitochondrial fusion protein (OPA1, Mfn1), abnormalities in mitochondrial autophagy protein (LC3BII/I, P62), decreased dopamine neuron (TH) expression, increased α-synuclein expression, inflammatory factors (IL-6, IL-1β, and TNF-α) release and microglia (Iba1) activation. In addition, we found that Cu

Topics: Adenosine Triphosphate; Aged; alpha-Synuclein; Animals; Copper; Mice; Mice, Transgenic; Mitochondria; Neurodegenerative Diseases; Parkinson Disease; Reactive Oxygen Species

Parkinson's disease (PD) is a common neurodegenerative disease with aggregation of α-synuclein (α-syn) in substantia nigra (SN). The association between the α-syn and ferroptosis in PD remains unclear. GSE49036 was obtained from the Gene Expression Omnibus (GEO) database and intersected with ferroptosis genes. Bioinformatics analysis was used to identify the potential differentially expressed genes (DEGs) included the development of Gene set enrichment analysis (GSEA), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction (PPI) network. We screened 8 key genes were modulated and crosslinked by 238 miRNAs. Additionally, 5 hub genes were predicted and 38 lncRNAs targeting 3 key miRNAs were revealed. Finally, 3 hub genes (PIK3CA, BRD4, ATM) and the key lncRNA (NEAT1) were verified in neurotoxic PD models. The in vitro experiments showed that PIK3CA and ATM were significantly upregulated or the BRD4 was downregulated in the rotenone treatment and they could be rescued by the specific ferroptosis inhibitor, liproxstatin-1. The expression of the key lncRNA NEAT1 were consistent with the hub genes in same models. This study identified the proposed NEAT1-PIK3CA/ATM ceRNA network may be a specific biomarker in α-syn driving ferroptosis as well as to predict clinical outcomes and therapeutic targets in PD patients.

Topics: alpha-Synuclein; Cell Cycle Proteins; Class I Phosphatidylinositol 3-Kinases; Ferroptosis; Humans; MicroRNAs; Neurodegenerative Diseases; Nuclear Proteins; Parkinson Disease; RNA, Long Noncoding; Transcription Factors

Lysosomes are acidic organelles that traffic throughout neurons delivering catabolic enzymes to distal regions of the cell and maintaining degradative demands. Loss of function mutations in the gene

Topics: alpha-Synuclein; Axonal Transport; Glucosylceramidase; Humans; Induced Pluripotent Stem Cells; Lysosomes; Male; Neurodegenerative Diseases; Neurons; Prosencephalon

Neurodegenerative disorders are characterized by the brain deposition of insoluble amyloidogenic proteins, such as α-synuclein or Tau, and the concomitant deterioration of cell functions such as the autophagy-lysosomal pathway (ALP). The ALP is involved in the degradation of intracellular macromolecules including protein aggregates. ALP dysfunction due to inherited defects in lysosomal or non-lysosomal proteins causes a group of diseases called lysosomal storage disorders (LSD) because of abnormal accumulation of lysosomal degradation substrates. Supporting the contribution of ALP defects in neurodegenerative diseases, deposition of amyloidogenic proteins occurs in LSD. Moreover, heterozygous mutations of several ALP genes represent risk factors for Parkinson's disease. The reciprocal contribution of α-synuclein accumulation and lysosomal dysfunction have been extensively studied. However, whether this adverse crosstalk also embraces Tau pathology needs more investigation. Here, we show in human primary fibroblasts that Tau seeds isolated from the brain of Alzheimer's disease induce Tau accumulation in acidic degradative organelles and lysosomal stress. Furthermore, inhibition of glucocerebrosidase, a lysosomal enzyme mutated in Gaucher's disease and a main risk for Parkinson's disease, causes lysosomal dysfunction in primary fibroblasts and contributes to the accumulation of Tau. Considering the presence of Tau lesions in Parkinson's disease as well as in multiple neurodegenerative disorders including Alzheimer's disease, our data call for further studies on strategies to alleviate ALP dysfunction as new therapeutic opportunity for neurodegenerative diseases and LSD.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloidogenic Proteins; Humans; Lysosomes; Neurodegenerative Diseases; Parkinson Disease; tau Proteins

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

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

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

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

Parkinson's disease, a neurodegenerative disease that affects 15 million people worldwide, is characterized by deposition of α-synuclein into Lewy Bodies in brain neurons. Although this disease is prevalent worldwide, a therapy or cure has yet to be found. Several small compounds have been reported to disrupt fibril formation. Among these compounds is a molecular tweezer known as CLR01 that targets lysine and arginine residues. This study aims to characterize how CLR01 interacts with various proteoforms of α-synuclein and how the structure of α-synuclein is subsequently altered. Native mass spectrometry (nMS) measurements of α-synuclein/CLR01 complexes reveal that multiple CLR01 molecules can bind to α-synuclein proteoforms such as α-synuclein phosphorylated at Ser-129 and α-synuclein bound with copper and manganese ions. The binding of one CLR01 molecule shifts the ability for α-synuclein to bind other ligands. Electron capture dissociation (ECD) with Fourier transform-ion cyclotron resonance (FT-ICR) top-down (TD) mass spectrometry of α-synuclein/CLR01 complexes pinpoints the locations of the modifications on each proteoform and reveals that CLR01 binds to the N-terminal region of α-synuclein. CLR01 binding compacts the gas-phase structure of α-synuclein, as shown by ion mobility-mass spectrometry (IM-MS). These data suggest that when multiple CLR01 molecules bind, the N-terminus of α-synuclein shifts toward a more compact state. This compaction suggests a mechanism for CLR01 halting the formation of oligomers and fibrils involved in many neurodegenerative diseases.

Topics: alpha-Synuclein; Brain; Humans; Mass Spectrometry; Neurodegenerative Diseases; Parkinson Disease

The α-synucleinopathies are a group of neurodegenerative diseases characterized by the deposition of α-synuclein aggregates (α-syn) in the brain. Currently, there is no suitable tracer to enable a definitive early diagnosis of these diseases. We reported candidates based on 4,4'-disarylbisthiazole (DABTA) scaffold with a high affinity towards α-syn and excellent selectivity over Aβ and tau fibrils. Based on prior in silico studies, a focused library of 23 halogen-containing and O-methylated DABTAs was prepared. The DABTAs were synthesized via a modified two-step Hantzsch thiazole synthesis, characterized, and used in competitive binding assays against [

Topics: alpha-Synuclein; Biomarkers; Humans; Ligands; Neurodegenerative Diseases; Protein Aggregates; Synucleinopathies

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder, yet effective treatments able to stop or delay disease progression remain elusive. The aggregation of a presynaptic protein, α-synuclein (aSyn), is the primary neurological hallmark of PD and, thus, a promising target for therapeutic intervention. However, the lack of consensus on the molecular properties required to specifically bind the toxic species formed during aSyn aggregation has hindered the development of therapeutic molecules. Recently, we defined and experimentally validated a peptide architecture that demonstrated high affinity and selectivity in binding to aSyn toxic oligomers and fibrils, effectively preventing aSyn pathogenic aggregation. Human peptides with such properties may have neuroprotective activities and hold a huge therapeutic interest. Driven by this idea, here, we developed a discriminative algorithm for the screening of human endogenous neuropeptides, antimicrobial peptides and diet-derived bioactive peptides with the potential to inhibit aSyn aggregation. We identified over 100 unique biogenic peptide candidates and ensembled a comprehensive database (aSynPEP-DB) that collects their physicochemical features, source datasets and additional therapeutic-relevant information, including their sites of expression and associated pathways. Besides, we provide access to the discriminative algorithm to extend its application to the screening of artificial peptides or new peptide datasets. aSynPEP-DB is a unique repository of peptides with the potential to modulate aSyn aggregation, serving as a platform for the identification of previously unexplored therapeutic agents. Database URL:  https://asynpepdb.ppmclab.com/.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease; Peptides

Amyloid cross-seeding and amyloid inhibition are two different research subjects being studied separately for different pathological purposes, in which amyloid cross-seeding targets to study the co-aggregation of different amyloid proteins and potential molecular links between different neurodegenerative diseases, while amyloid inhibition aims to design different molecules for preventing amyloid aggregation. While both amyloid cross-seeding and amyloid inhibition are critical for better understanding the pathological causes of different neurodegenerative diseases including Parkinson disease (PD) and Type 2 diabetes (T2D), less efforts have been made to reconcile the two phenomena. Herein, we proposed a new preventive strategy to demonstrate (a) the cross-seeding of octapeptide TKEQVTNV from α-synuclein (associated with PD) with hIAPP (associated with T2D) and (b) the cross-seeding-promoted hIAPP fibrillization and cross-seeding-reduced hIAPP toxicity. Collective results confirmed that TKEQVTNV can indeed cross-seed with hIAPP monomers and oligomers, not protofibrils, to form β-structure-rich fibrils and to accelerate hIAPP fibrillization. Moreover, such cross-seeding-induced promotion effect by TKEQVTNV also rescued the pancreatic cells from hIAPP-induced cytotoxicity by increasing cell viability and reducing cell apoptosis simultaneously. This work provides a new angle to discover amyloid fragments and use them as amyloid modulators (inhibitors or promotors) to interfere with amyloid aggregation of other amyloid proteins, as well as sequence/structure basis to explore the amyloid cross-seeding between different amyloid proteins that may help explain a potential molecular talk between different neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Amyloidogenic Proteins; Humans; Islet Amyloid Polypeptide; Neurodegenerative Diseases

Alpha-synuclein (aSyn) is a vertebrate protein, normally found within the presynaptic nerve terminal and nucleus, which is known to form somatic and neuritic aggregates in certain neurodegenerative diseases. Disease-associated aggregates of aSyn are heavily phosphorylated at serine-129 (pSyn), while normal aSyn protein is not. Within the nucleus, aSyn can directly bind DNA, but the mechanism of binding and the potential modulatory roles of phosphorylation are poorly understood. Here we demonstrate using a combination of electrophoretic mobility shift assay and atomic force microscopy approaches that both aSyn and pSyn can bind DNA within the major groove, in a DNA length-dependent manner and with little specificity for DNA sequence. Our data are consistent with a model in which multiple aSyn molecules bind a single 300 base pair (bp) DNA molecule in such a way that stabilizes the DNA in a bent conformation. We propose that serine-129 phosphorylation decreases the ability of aSyn to both bind and bend DNA, as aSyn binds 304 bp circular DNA forced into a bent shape, but pSyn does not. Two aSyn paralogs, beta- and gamma-synuclein, also interact with DNA differently than aSyn, and do not stabilize similar DNA conformations. Our work suggests that reductions in aSyn's ability to bind and bend DNA induced by serine-129 phosphorylation may be important for modulating aSyn's known roles in DNA metabolism, including the regulation of transcription and DNA repair.

Topics: alpha-Synuclein; DNA; Neurodegenerative Diseases; Phosphorylation; Serine; Structure-Activity Relationship

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders, which characterized by increased pathological marker protein, α-synuclein (α-syn) and phosphorylated-Ser129-α-syn in the extracellular fluids. Current methods of measuring the p-Ser129-α-syn concentration in cerebrospinal fluid for PD are based on ELISA method, however, the amount of area under the curve (AUC) to predict PD is around 0.7-0.8. Higher confidence level of AUC in p-Ser129-α-syn quantification for the early diagnosis of PD would be essential.. Detection of p-Ser129-α-syn in diluted human serum for diagnosis of PD was investigated by a modified paired surface plasma wave biosensor (PSPWB) using a quarter wave plate for better detection performance. The method combining an immunoassay and non-labeled technique measures the p-Ser129-α-syn level with high sensitivity and specificity. Ten patients with PD at early stage (Hohn & Yahr stage I and II) and 11 age-matched healthy control participants were recruited for measurement of serum p-Ser129-α-syn.. AUC of the p-Ser129-α-syn in diluted human serum was 0.92 and it shows that p-Ser129-α-syn in diluted human serum could be used as a sensitive biomarker for the diagnosis of PD in clinics. Results clearly show that the measured p-Ser129-α-syn concentration in diluted human serum displays a statistical significance between health control subjects and PD patients.. P-Ser129-α-syn has low abundance in human serum, high detection sensitivity and specificity are critical to the success of the diagnosis of PD in clinics. In this study, a modified PSPWB was developed that the limit of detection at 1 ng/mL for p-Ser129-α-syn (standard) spiked into diluted human serum of a healthy control was performed. This result shows that the modified PSPWB can be used as a platform for detecting p-Ser129-α-syn in diluted human serum as a potential biomarker for PD.

Topics: alpha-Synuclein; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease; Phosphorylation

Parkinson's disease (PD) is an incurable neurodegenerative disease characterized by aggregation of pathological alpha-synuclein (α-syn) and loss of dopaminergic neuron in the substantia nigra. Inhibition of phosphorylation of the α-syn has been shown to mediate alleviation of PD-related pathology. Protein phosphatase 2A (PP2A), an important serine/threonine phosphatase, plays an essential role in catalyzing dephosphorylation of the α-syn. Here, we identified and validated cancerous inhibitor of PP2A (CIP2A), as a potential diagnostic biomarker for PD. Our data showed that plasma CIP2A concentrations in PD patients were significantly lower compared to age- and sex-matched controls, 1.721 (1.435-2.428) ng/ml vs 3.051(2.36-5.475) ng/ml, p < 0.0001. The area under the curve of the plasma CIP2A in distinguishing PD from the age- and sex-matched controls was 0.776. In addition, we evaluated the role of CIP2A in PD-related pathogenesis in PD cellular and MPTP-induced mouse model. The results demonstrated that CIP2A is upregulated in PD cellular and MPTP-induced mouse models. Besides, suppression of the CIP2A expression alleviates rotenone induced aggregation of the α-syn as well as phosphorylation of the α-syn in SH-SY5Y cells, which is associated with increased PP2A activity. Taken together, our data demonstrated that CIP2A plays an essential role in the mechanisms related to PD development and might be a novel PD biomarker.

Topics: alpha-Synuclein; Animals; Autoantigens; Biomarkers; Humans; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Mice; Neurodegenerative Diseases; Parkinson Disease; Protein Phosphatase 2; Substantia Nigra

Preclinical and clinical studies support a strong association between mutations in the GBA1 gene that encodes beta-glucocerebrosidase (GCase) (EC 3.2.1.45; glucosylceramidase beta) and Parkinson's disease (PD). Alpha-synuclein (AS), a key player in PD pathogenesis, and GBA1 mutations may independently and synergistically cause lysosomal dysfunction and thus, embody clinically well-validated targets of the neurodegenerative disease process in PD. However, in vivo models, recapitulating pathological features of PD that can be used to dissect the nature of the complex relationship between GCase and AS on the nigrostriatal axis, the region particularly vulnerable in PD, are direly needed. To address this, we implemented a bidirectional approach in mice to examine the effects of: 1) GCase overexpression (wild-type and mutant N370S GBA) on endogenous AS levels and 2) downregulation of endogenous GCase (Gba) combined with AS overexpression. Striatal delivery of viral-mediated GCase overexpression revealed minimal effects on cortical and nigrostriatal AS tissue levels and no significant effect on dopaminergic system integrity. On the other hand, microRNA (miR)-mediated Gba1 downregulation (miR Gba), combined with virus-mediated human AS overexpression (+AS), yields decreased GCase activity in the cortex, mimicking levels seen in GBA1 heterozygous carriers (30-40%), increased astrogliosis and microgliosis, decreased striatal dopamine levels (50% compared to controls) and loss of nigral dopaminergic neurons (~33%)- effects that were all reversible with miR rescue. Most importantly, the synergistic neurodegeneration of miR Gba + AS correlated with augmented AS accumulation and extracellular release in the striatum. Collectively, our results suggest that GCase downregulation alone is not sufficient to recapitulate key pathological features of PD in vivo, but its synergistic interplay with AS, via increased AS levels and extracellular release, drives nigrostriatal neurodegeneration. Furthermore, we report a novel double-hit GBA-AS model that can be used to identify putative mechanisms driving PD pathophysiology and can be subsequently used to test novel therapeutic approaches.

Topics: alpha-Synuclein; Animals; Dopaminergic Neurons; Down-Regulation; Glucosylceramidase; Lysosomes; Mice; Mutation; Neurodegenerative Diseases

Topics: alpha-Synuclein; Animals; Autophagy; Mice; Microglia; Neurodegenerative Diseases; Parkinson Disease; TRPV Cation Channels

Neurodegenerative diseases are debilitating impairments that affect millions of people worldwide and are characterized by progressive degeneration of structure and function of the central or peripheral nervous system. Effective biomarkers for neurodegenerative diseases can be used to improve the diagnostic workup in the clinic as well as facilitate the development of effective disease-modifying therapies. Progranulin (PGRN) has been reported to be involved in various neurodegenerative disorders. Hence, in the current study we systematically compared the inflammation and accumulation of typical neurodegenerative disease markers in the brain tissue between PGRN knockout (PGRN KO) and wildtype (WT) mice. We found that PGRN deficiency led to significant neuron loss as well as activation of microglia and astrocytes in aged mice. Several characteristic neurodegenerative markers, including α-synuclein, TAR DNA-binding protein 43 (TDP-43), Tau, and β-amyloid, were all accumulated in the brain of PGRN-deficient mice as compared to WT mice. Moreover, higher aggregation of lipofuscin was observed in the brain tissue of PGRN-deficient mice compared with WT mice. In addition, the autophagy was also defective in the brain of PGRN-deficient mice, indicated by the abnormal expression level of autophagy marker LC3-II. Collectively, comprehensive assays support the idea that PGRN plays an important role during the development of neurodegenerative disease, indicating that PGRN might be a useful biomarker for neurodegenerative diseases in clinical settings.

Topics: Aging; alpha-Synuclein; Amyloid beta-Peptides; Animals; Astrocytes; Autophagy; Biomarkers; Brain; DNA-Binding Proteins; Lipofuscin; Mice, Knockout; Microglia; Neurodegenerative Diseases; Neurons; Phosphorylation; Progranulins; Protein Aggregates; tau Proteins

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

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

How do protein aggregates contribute to neurodegenerative disorders, and can they be therapeutically targeted? In this issue of Neuron, Stojkovska et al. (2022) show that aggregated α-synuclein disrupts ER and lysosomal function in Parkinson's disease patient-derived neurons and that combined enhancement of multiple arms of the proteostasis network improves these defects.

Topics: alpha-Synuclein; Humans; Lysosomes; Neurodegenerative Diseases; Neurons; Parkinson Disease; Protein Aggregates

Blood and cerebrospinal fluid represent emerging candidate fluids for biomarker identification in Parkinson's disease (PD).. We studied 8 individuals carrying the E46K-SNCA mutation (3 PD dementia (PDD), 1 tremor-dominant PD, 2 young rigid-akinetic PD and 2 asymptomatic) and 8 age- and sex-matched healthy controls. We quantified the levels of total alpha-synuclein (a-syn), neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), Tau and ubiquitin carboxy-terminal hydrolase L1 (UCHL1) with SiMoA (Quanterix) in cerebrospinal fluid (CSF) of mutation carriers and in serum of all participants. The correlation between the concentration of biofluid markers and clinical outcomes was evaluated.. Although based on a small number of cases, CSF a-syn was decreased in symptomatic E46K-SNCA carriers compared to the asymptomatic ones. Asymptomatic carriers exhibited similar serum biomarker levels as compared to matched controls, except for serum a-syn, which was higher in asymptomatic individuals. Carriers with PDD diagnosis displayed increased levels of serum NfL and GFAP compared to matched controls. These findings highly correlated with cognitive and motor status of E46K-SNCA carriers, but not with disease duration.. Patients with familial forms of neurodegenerative disease exhibit variable penetrance of the phenotype and are exceptionally valuable for delineating biomarkers. Serum and CSF molecular biomarkers in E46K-SNCA mutation carriers show that a-syn might be suitable to track the conversion from asymptomatic to PD, whereas NfL and GFAP might serve to foresee the progression to PD dementia. These findings should be interpreted with caution and need to be replicated in other genetic synucleinopathy cohorts.

Topics: alpha-Synuclein; Alzheimer Disease; Biomarkers; Humans; Mutation; Neurodegenerative Diseases; Parkinson Disease

A wide variety of oligomeric structures are formed during the aggregation of proteins associated with neurodegenerative diseases. Such soluble oligomers are believed to be key toxic species in the related disorders; therefore, identification of the structural determinants of toxicity is of upmost importance. Here, we analysed toxic oligomers of α-synuclein and its pathological variants in order to identify structural features that could be related to toxicity and found a novel structural polymorphism within G51D oligomers. These G51D oligomers can adopt a variety of β-sheet-rich structures with differing degrees of α-helical content, and the helical structural content of these oligomers correlates with the level of induced cellular dysfunction in SH-SY5Y cells. This structure-function relationship observed in α-synuclein oligomers thus presents the α-helical structure as another potential structural determinant that may be linked with cellular toxicity in amyloid-related proteins.

Topics: alpha-Synuclein; Humans; Mutation; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; Protein Binding; Protein Multimerization; Spectrum Analysis

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

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

Parkinson's disease (PD) is characterized by intra-neuronal deposition of the protein α-synuclein (α-syn) and by deficiencies of the catecholamines dopamine and norepinephrine (NE) in the brain and heart. Accumulation of α-syn in sympathetic noradrenergic nerves may provide a useful PD biomarker; however, whether α-syn buildup is pathophysiological has been unclear. If it were, one would expect associations of intra-neuronal α-syn deposition with catecholaminergic denervation and with decreased NE contents in the same samples.. We assayed immunoreactive α-syn and tyrosine hydroxylase (TH, a marker of catecholaminergic innervation) concurrently with catecholamines in coded post-mortem scalp skin, submandibular gland (SMG), and apical left ventricular myocardial tissue samples from 14 patients with autopsy-proven PD and 12 age-matched control subjects who did not have a neurodegenerative disease.. The PD group had increased α-syn in sympathetic noradrenergically innervated arrector pili muscles (5.7 times control, P < 0.0001), SMG (35 times control, P = 0.0011), and myocardium (11 times control, P = 0.0011). Myocardial TH in the PD group was decreased by 65% compared to the control group (P = 0.0008), whereas the groups did not differ in TH in either arrector pili muscles or SMG. Similarly, myocardial NE was decreased by 92% in the PD group (P < 0.0001), but the groups did not differ in NE in either scalp skin or SMG.. PD entails increased α-syn in skin, SMG, and myocardial tissues. In skin and SMG, augmented α-syn deposition in sympathetic nerves does not seem to be pathogenic. The pathophysiological significance of intra-neuronal α-syn deposition appears to be organ-selective and prominent in the heart.

Topics: alpha-Synuclein; Autopsy; Biomarkers; Catecholamines; Humans; Neurodegenerative Diseases; Norepinephrine; Parkinson Disease

α-Synuclein (α-syn) aggregates are major components of pathological hallmarks observed in the human brain affected by neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. It is known that α-syn aggregates are involved in the pathogenesis of these neurodegenerative diseases. However, detailed mechanisms have not been fully elucidated. Therefore, the development of radiolabeled imaging probes to detect α-syn aggregates in vivo may contribute to early diagnosis and pathophysiological elucidation of neurodegenerative diseases affected by α-syn aggregates. In the present study, we designed and synthesized four radioiodinated phenylbenzofuranone (PBF) derivatives: [

Topics: alpha-Synuclein; Brain; Humans; Neurodegenerative Diseases; Parkinson Disease

Topics: Aged; alpha-Synuclein; Dendritic Cells; Humans; Neurodegenerative Diseases; Parkinson Disease; Pentacyclic Triterpenes; T-Lymphocytes

Alpha-synuclein (α-syn) exhibits pathological misfolding in many human neurodegenerative disorders. We previously showed that α-syn is arginylated in the mouse brain and that lack of arginylation leads to neurodegeneration in mice.. Here, we tested α-syn arginylation in human brain pathology using newly derived antibodies in combination with Western blotting, biochemical assays, and experiments in live neurons.. We found that α-syn was arginylated in the human brain on E46 and E83, two sites previously implicated in α-syn pathology and familial cases of Parkinson's disease. The levels of arginylation in different brain samples ranged between ~ 3% and ~ 50% of the total α-syn pool, and this arginylation nearly exclusively concentrated in the subcellular α-syn fraction that sedimented at low centrifugation speeds and appeared to be simultaneously targeted by multiple posttranslational modifications. Arginylated α-syn was less susceptible to S129 phosphorylation and pathological aggregation in neurons. The arginylation level inversely correlated with the overall α-syn levels and with patient age, suggesting a possible causal relationship between arginylation decline and α-syn-dependent neuropathology.. We propose that α-syn arginylation constitutes a potential neuroprotective mechanism that prevents its abnormal accumulation during neurodegeneration and aging in the human brain.

Topics: alpha-Synuclein; Animals; Brain; Humans; Mice; Neurodegenerative Diseases; Parkinson Disease; Synucleinopathies

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Line, Tumor; Humans; Mice; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; RNA, Long Noncoding

Parkinson's disease (PD) is the most common motor-associated neurodegenerative disease. Although the pathogenesis of PD is still wrapped in the mist, accumulating evidence indicates that mitochondrial dysfunction contributes to the onset and progression of PD. We previously reported that the lysosomal protease asparagine endopeptidase (AEP) cleaves α-synuclein in the brains of PD patients. The major product, α-synuclein 1-103, significantly promotes PD-like histological changes and motor dysfunction. However, the underlying molecular mechanisms remain unknown. Here we show that α-synuclein 1-103 fragment interacts with mitochondria and induces morphological and functional abnormalities of mitochondria. Furthermore, we investigated the protective effects of 7,8-dihydroxyflavone (7,8-DHF) on mitochondrial dysfunction induced by α-synuclein 1-103 fragment. We found that 7,8-DHF ameliorated α-synuclein 1-103-induced mitochondrial impairment and motor dysfunction. These results indicate that 7,8-DHF represents a novel oral bioactive therapeutic agent for treating PD.

Topics: alpha-Synuclein; Animals; Flavones; Humans; Mice; Mice, Transgenic; Mitochondria; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is a neurodegenerative disease characterised by the formation of Lewy bodies and progressive loss of dopaminergic (DA) neurons in the substantia nigra. Lewy bodies mainly consist of α-synuclein, which plays a critical role in the pathophysiology of PD. The α-synuclein is encoded by the

Topics: alpha-Synuclein; Animals; Drosophila; Drosophila melanogaster; Gene Expression; Neurodegenerative Diseases; Parkinson Disease

While neurodegenerative diseases affect millions of patients worldwide, there are insufficient available therapeutics to halt or slow down the progression of these diseases. A key pathological feature of several neurodegenerative diseases is the oligomerization and aggregation of specific intrinsically disordered proteins (IDPs) creating neuronal deposits, such as Lewy bodies in Parkinson's disease. Clearance of these pathogenic, aggregation-prone IDPs is mediated by the 20S isoform of the human proteasome. Thus, enhancing the 20S proteasome-mediated proteolysis could be a very useful therapeutic pathway to prevent neurotoxicity. Here, we report the successful development of sub-microM 20S proteasome activators based on a phenothiazine scaffold. This class of compounds prevented the accumulation of pathologically relevant IDPs, such as the pathogenic A53T mutated α-synuclein,

Topics: alpha-Synuclein; Animals; Humans; Intrinsically Disordered Proteins; Mammals; Neurodegenerative Diseases; Parkinson Disease; Proteasome Endopeptidase Complex; Proteolysis; Synucleinopathies

Parkinson's disease (PD) is a multi-factorial neurodegenerative disease affecting motor function of patients. The hall markers of PD are dopaminergic neuron loss in the midbrain and the presence of intra-neuronal inclusion bodies mainly composed of aggregation-prone protein alpha-synuclein (α-syn). Ubiquitin-proteasome system (UPS) is a multi-step reaction process responsible for more than 80% intracellular protein degradation. Impairment of UPS function has been observed in the brain tissue of PD patients. PDE4 inhibitors have been shown to activate cAMP-PKA pathway and promote UPS activity in Alzheimer's disease model. α-mangostin is a natural xanthonoid with broad biological activities, such as antioxidant, antimicrobial and antitumour activities. Structure-based optimizations based on α-mangostin produced a potent PDE4 inhibitor, 4e. Herein, we studied whether 4e could promote proteasomal degradation of α-syn in Parkinson's disease models through PKA activation.. cAMP Assay was conducted to quantify cAMP levels in samples. Model UPS substrates (Ub-G76V-GFP and Ub-R-GFP) were used to monitor UPS-dependent activity. Proteasome activity was investigated by short peptide substrate, Suc-LLVY-AMC, cleavage of which by the proteasome increases fluorescence sensitivity. Tet-on WT, A30P, and A53T α-syn-inducible PC12 cells and primary mouse cortical neurons from A53T transgenic mice were used to evaluate the effect of 4e against α-syn in vitro. Heterozygous A53T transgenic mice were employed to assess the effect of 4e on the clearance of α-syn in vivo, and further validations were applied by western blotting and immunohistochemistry.. Taken together, α-mangostin derivative 4e, a PDE4 inhibitor, efficiently activated the cAMP/PKA pathway in neuronal cells, and promoted UPS activity as evidenced by enhanced degradation of UPS substrate Ub-G76V-GFP and Ub-R-GFP, as well as elevated proteasomal enzyme activity. Interestingly, 4e dramatically accelerated degradation of inducibly-expressed WT and mutant α-syn in PC12 cells, in a UPS dependent manner. Besides, 4e consistently activated PKA in primary neuron and A53T mice brain, restored UPS inhibition and alleviated α-syn accumulation in the A53T mice brain.. 4e is a natural compound derived highly potent PDE4 inhibitor. We revealed its potential effect in promoting UPS activity to degrade pathogenic proteins associated with PD.

Topics: alpha-Synuclein; Animals; Cyclic AMP-Dependent Protein Kinases; Dopaminergic Neurons; Enzyme Activation; Humans; Mice; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease; Phosphodiesterase 4 Inhibitors; Proteasome Endopeptidase Complex; Rats; Ubiquitin; Xanthones

Parkinson's disease (PD) is the second most neurodegenerative disease caused due to synucleinopathy leads to the death of dopaminergic and serotonergic neurons. The approach to reduce synucleinopathy paves the therapeutic way in PD management. Recent studies highlight anti-Parkinsonism effect of Hytrin that regulates energy homeostasis via activation of mitochondrial redox regulator; IDH2 leading to attenuation of synucleinopathy. However, the burst release kinetics of Hytrin restricts its therapeutic potential. Therefore, we aimed to improve Hytrin release kinetics through nanocarrier mediated delivery, replenish dopamine and serotonin by formulating Hytrin loaded polydopamine serotonin nanohybrid for PD protection. Present study also explores IDH2 mediated neuroprotective action in retardation of synucleinopathy for PD prevention. Nanoformulation has shown effective neurotherapeutic potential by improving Hytrin release profile in the reduction of PD symptoms in vitro and ex vivo. The neuroprotective effect has been attributed to IDH2 induction and alpha-synuclein reduction against rotenone insults. The direct physical interaction of IDH2 and alpha-synuclein, PD hallmark has been uncovered. The study divulges that the restorative effect of our nanoformulation significantly retards the PD deficits byinducing IDH2 mediated alpha-synuclein ubiquitination and proteasomal degradation pathway.

Topics: alpha-Synuclein; Dopamine; Humans; Indoles; Neurodegenerative Diseases; Neuroprotective Agents; Parkinson Disease; Polymers; Prazosin; Serotonin; Synucleinopathies

Most neurodegenerative disorders take decades to develop, and their early detection is challenged by confounding non-pathological ageing processes. Therefore, the discovery of genes and molecular pathways in both peripheral and brain tissues that are highly predictive of disease evolution is necessary. To find genes that influence Alzheimer's disease (AD) and Parkinson's disease (PD) pathogenesis, human RNA-Seq transcriptomic data from Brodmann Area 9 (BA9) of the dorsolateral prefrontal cortex (DLPFC), whole blood (WB), and peripheral blood mononuclear cells (PBMC) were analysed using a combination of differential gene expression and a random forest-based machine learning algorithm. The results suggest that there is little overlap between PD and AD, and the AD brain signature is unique mainly compared to blood-based samples. Moreover, the AD-BA9 was characterised by changes in 'nervous system development' with Myocyte-specific enhancer factor 2C (

Topics: alpha-Synuclein; Alzheimer Disease; Humans; Leukocytes, Mononuclear; Neurodegenerative Diseases; Parkinson Disease; Transcriptome

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

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

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

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

Isolated REM sleep behaviour disorder (iRBD) is a synucleinopathy characterized by abnormal behaviours and vocalizations during REM sleep. Most iRBD patients develop dementia with Lewy bodies, Parkinson's disease or multiple system atrophy over time. Patients with iRBD exhibit brain atrophy patterns that are reminiscent of those observed in overt synucleinopathies. However, the mechanisms linking brain atrophy to the underlying alpha-synuclein pathophysiology are poorly understood. Our objective was to investigate how the prion-like and regional vulnerability hypotheses of alpha-synuclein might explain brain atrophy in iRBD. Using a multicentric cohort of 182 polysomnography-confirmed iRBD patients who underwent T1-weighted MRI, we performed vertex-based cortical surface and deformation-based morphometry analyses to quantify brain atrophy in patients (67.8 years, 84% male) and 261 healthy controls (66.2 years, 75%) and investigated the morphological correlates of motor and cognitive functioning in iRBD. Next, we applied the agent-based Susceptible-Infected-Removed model (i.e. a computational model that simulates in silico the spread of pathologic alpha-synuclein based on structural connectivity and gene expression) and tested if it recreated atrophy in iRBD by statistically comparing simulated regional brain atrophy to the atrophy observed in patients. The impact of SNCA and GBA gene expression and brain connectivity was then evaluated by comparing the model fit to the one obtained in null models where either gene expression or connectivity was randomized. The results showed that iRBD patients present with cortical thinning and tissue deformation, which correlated with motor and cognitive functioning. Next, we found that the computational model recreated cortical thinning (r = 0.51, P = 0.0007) and tissue deformation (r = 0.52, P = 0.0005) in patients, and that the connectome's architecture along with SNCA and GBA gene expression contributed to shaping atrophy in iRBD. We further demonstrated that the full agent-based model performed better than network measures or gene expression alone in recreating the atrophy pattern in iRBD. In summary, atrophy in iRBD is extensive, correlates with motor and cognitive function and can be recreated using the dynamics of agent-based modelling, structural connectivity and gene expression. These findings support the concepts that both prion-like spread and regional susceptibility account for the atrophy observed in prodro

Topics: Aged; alpha-Synuclein; Atrophy; Brain; Cerebral Cortical Thinning; Female; Gene Expression; Humans; Male; Neurodegenerative Diseases; Prions; REM Sleep Behavior Disorder; Synucleinopathies

Parkinson's disease (PD) is the second most common neurodegenerative disease with motor disorders as the key clinical features. BDNF/TrkB neurotrophic signalings are progressively reduced, whereas δ-secretase, a protease that cleaves α-synuclein (α-Syn) at N103 and promotes its aggregation and neurotoxicity, is gradually escalated in PD patient brains, associated with dopaminergic neuronal loss in the Substantia Nigra. Here, we show that stimulation of deficient BDNF/TrkB signalings with its small molecular agonist CF3CN displays the promising therapeutic effect, and blockade of δ-secretase with an optimal specific inhibitor #11A exhibits marked therapeutic effect, and combination of both demonstrates additive restorative efficacy in MPTP-induced human SNCA transgenic PD mice. Upon oral administration, CF3CN robustly activates TrkB-mediated neurotrophic pathway in the brains of SNCA mice and decreases α-Syn N103 cleavage by δ-secretase, and #11A strongly blocks δ-secretase and reduces α-Syn N103 fragmentation, increasing TH-positive dopaminergic neurons. The mixture of CF3CN and #11A shows the maximal TH and dopamine levels with demonstrable BDNF as compared to negligible BDNF in vehicle-treated MPTP/SNCA mice, leading to the climaxed motor functions. Notably, both compounds possess the appropriate in vivo PK profiles. Hence, our findings support that CF3CN and #11A are promising therapeutic pharmaceutical agents for treating PD.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; alpha-Synuclein; Amyloid Precursor Protein Secretases; Animals; Brain-Derived Neurotrophic Factor; Dopamine; Dopaminergic Neurons; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease; Signal Transduction; Substantia Nigra

The development of axonal pathology is a key characteristic of many neurodegenerative disease such as Parkinson's disease and Alzheimer's disease. With advanced disease progression, affected axons do display several signs of pathology such as swelling and fragmentation. In the AAV vector-mediated alpha-synuclein overexpression model of Parkinson's disease, large (> 20 µm. This report describes a novel, macro-based workflow to quantify axonal pathology in the form of axonal swellings in the AAV vector-based alpha-synuclein overexpression model. Specifically, the approach is using background correction and thresholding before quantification of structures in 3D throughout a tissue stack.. The method was used to quantify TH and aSYN axonal swellings in the prefrontal cortex, striatum, and hippocampus. Regional differences in volume and number of axonal swellings were observed for both in TH and aSYN, with the striatum displaying the greatest signs of pathology.. Existing methods for the quantification of axonal pathology do either rely on proprietary software or are based on manual quantification. The ImageJ workflow described here provides a method to objectively quantify axonal swellings both in volume and number.. The method described can readily assess axonal pathology in preclinical rodent models of Parkinson's disease and can be easily adapted to other model systems and/or markers.

Topics: alpha-Synuclein; Animals; Axons; Neurodegenerative Diseases; Parkinson Disease; Rodentia

Parkinson's disease (PD) is the most common neurodegenerative disease. Along with the population aging of China, the increase of PD patients in China will result in serious economic and medical burdens. The typical pathological characteristics of PD are the death of dopaminergic neurons in the substantia nigra compacta and the pathological inclusion bodies formed by abnormally aggregated amyloid alpha-synuclein (α-Syn) in dopaminergic neurons, which is also named as Lewy body. Studies have found that the Lewy body exists not only in the central nervous system, but also in the peripheral nervous system. The abundant enteric nervous system in the gut is called the "second brain". The discovery of the gut-brain axis also proves that α-Syn can be transmitted bilaterally between the brain and the gut. The gut microbiota was shown to be involved in the formation and transmission of pathological α-Syn. Therefore, this article summarized the bilateral transmission relationship of α-Syn in the brain and the gut and illustrated the influence of gut microbiota on the abnormal aggregation of α-Syn. Combined with the current progresses on PD patients and animal models especially the non-human primate experiments, this article aimed to provide a reference for the screening and diagnosis of PD.

Topics: alpha-Synuclein; Animals; Brain-Gut Axis; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease

The propagation and accumulation of pathological α-synuclein protein is thought to underlie the clinical symptoms of the neurodegenerative movement disorder Parkinson's disease (PD). Consequently, there is significant interest in identifying the mechanisms that contribute to α-synuclein pathology, as these may inform therapeutic targets for the treatment of PD. One protein that appears to contribute to α-synuclein pathology is the innate immune pathogen recognition receptor, toll-like receptor 2 (TLR2). TLR2 is expressed on neurons, and its activation results in the accumulation of α-synuclein protein; however, the precise mechanism by which TLR2 contributes to α-synuclein pathology is unclear. Herein we demonstrate using human cell models that neuronal TLR2 activation acutely impairs the autophagy lysosomal pathway and markedly potentiates α-synuclein pathology seeded with α-synuclein preformed fibrils. Moreover, α-synuclein pathology could be ameliorated with a novel small molecule TLR2 inhibitor, including in induced pluripotent stem cell-derived neurons from a patient with PD. These results provide further insight into how TLR2 activation may promote α-synuclein pathology in PD and support that TLR2 may be a potential therapeutic target for the treatment of PD.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Neurons; Parkinson Disease; Toll-Like Receptor 2

Parkinson's disease (PD) is a common neurodegenerative disease. Previously we identified tetranectin (TN) as a differentially expressed protein in the cerebrospinal fluid of PD patients, and we were surprised to find that TN knockout mice developed PD features. However, the specific role of TN in PD has not been clarified. In this study, we aimed to determine the effect of exogenous TN on cellular PD models and elucidate the underlying mechanisms. We found that exogenous TN could alleviate pre-formed-fibrils (PFFs)-induced synucleinopathies in SH-SY5Y cells and reduce the cell-to-cell transmission of α-synuclein (SYN). We also found that TN can promote the degradation of SYN by plasmin, which may account for its effect on cellular PD models. Moreover, administration of SYN/PFFs decreased the expression of TN and increased the expression of plasminogen activator inhibitor-1 (PAI-1) in SH-SY5Y cells, thereby reducing plasmin activity. Our findings depict a possible SYN-TN-plasmin interaction in which elevated levels of extracellular SYN monomers and aggregates in PD diminish the production of TN and PAI-1. Such changes lead to a reduced plasmin activity, which in turn reduces the degradation of extracellular SYN, thus forming a vicious cycle.

Topics: alpha-Synuclein; Animals; Fibrinolysin; Humans; Lectins, C-Type; Mice; Neuroblastoma; Neurodegenerative Diseases; Parkinson Disease; Plasminogen; Plasminogen Activator Inhibitor 1; Synucleinopathies

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

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

Alpha-synuclein (αSyn) and tau are abundant multifunctional neuronal proteins, and their intracellular deposits have been linked to many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Despite the disease relevance, their physiological roles remain elusive, as mice with knock-out of either of these genes do not exhibit overt phenotypes. To reveal functional cooperation, we generated αSyn

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Female; Male; Mice; Mice, Knockout; Neurodegenerative Diseases; Parkinson Disease

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

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

Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder characterized by the deposition of amyloid-β protein (Aβ) within brain blood vessels that develops in elderly people and Alzheimer's disease (AD) patients. Therefore, the investigation of biomarkers able to differentiate CAA patients from AD patients and healthy controls (HC) is of great interest, in particular in peripheral fluids.. The current study aimed to detect the neurodegenerative disease (ND)-related protein (i.e., Aβ1-40, Aβ1-42, tau, and α-synuclein) levels in both red blood cells (RBCs) and plasma of CAA patients and HC, evaluating their role as putative peripheral biomarkers for CAA.. For this purpose, the proteins' concentration was quantified in RBCs and plasma by homemade immunoenzymatic assays in an exploratory cohort of 20 CAA patients and 20 HC.. The results highlighted a significant increase of Aβ1-40 and α-synuclein concentrations in both RBCs and plasma of CAA patients, while higher Aβ1-42 and t-tau levels were detected only in RBCs of CAA individuals compared to HC. Moreover, Aβ1-42/Aβ1-40 ratio increased in RBCs and decreased in plasma of CAA patients. The role of these proteins as candidate peripheral biomarkers easily measurable with a blood sample in CAA needs to be confirmed in larger studies.. In conclusion, we provide evidence concerning the possible use of blood biomarkers for contributing to CAA diagnosis and differentiation from other NDs.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Cerebral Amyloid Angiopathy; Humans; Neurodegenerative Diseases; tau Proteins

Alpha synuclein (αSN) is a widely distributed protein in vertebrates whose physiological significance in many tissues remains unclear, being a key protein present in neurodegenerative disease such as Parkinson's Disease, Lewy Body Dementia, and in Sporadic-Inclusion Body Myositis. We search for αSN in skeletal muscle (SM) and neuronal plasma membrane isolated from brain (BR) from young and old rats.. In isolated Sarcolemma from SM and from myelin-free neuronal plasma membrane isolated from BR, we determine by Western blot with anti-αSN (2B2D1) and anti-P-αSN (EP1536Y) the αSN membrane distribution, and the SM αSN intra and extracellular localization.. In SM and BR, αSN is present in cytosol (CYT) as monomer and oligomer structures mainly tetramers (TM) and in plasma membranes as oligomers (TM and PM). All αSN oligomers were localized in non-lipid rafts and their distribution was unaffected by cholesterol-depletion with Methyl-β-Cyclodextrin. Membranes with natively high cholesterol content such as Transverse Tubules in SM and myelin in BR, reduce the presence of αSN. Under the same experimental conditions, aged SM and BR plasma membranes show ≈2 folds more αSN. In SM, αSN is extruded without cell damage in young and old rats.. We conclude that oligomeric αSN are regularly present in SM and BR plasma membranes of healthy young and old rats. Interestingly, low-cholesterol content membranes promote αSN interaction. SM, the largest tissue in vertebrate body is a source of αSN and may contribute to the presence of αSN in extracellular fluids.

Topics: alpha-Synuclein; Animals; Cholesterol; Muscle, Skeletal; Neurodegenerative Diseases; Parkinson Disease; Rats

Parkinson's disease (PD) is the second most neurodegenerative disease after Alzheimer's disease. Accumulating knowledge points to the notion that abnormal aggregation of alpha-synuclein (αSyn) starts in the gut and ascends to the substantia nigra via the vagus nerve in about a half of PD patients. Epidemiological studies revealed that ulcerative colitis (UC) increases a risk for PD 1.3 to 1.8-folds. However, it remains unknown whether αSyn is abnormally aggregated in the enteric neurons in UC patients.. We first inspected and optimized the immunostaining protocols with an anti-phosphorylated αSyn antibody, pSyn#64, using the brain and the gut of eight autopsied cases (five with PD and three without PD). Then, we examined abnormal αSyn aggregation in the enteric neurons in 23 and 18 colectomized patients with and without UC, respectively. Five or more sections were stained for αSyn in each of 87 and 25 paraffin- embedded blocks in patients with and without UC, respectively.. Ten different protocols of epitope exposure appropriately stained aggregated αSyn in the brain, but only complete lack of epitope exposure stained aggregated αSyn in the colon with low background. Abnormal αSyn aggregates, which was confirmed by co-localization of p62, in the enteric neurons were detected in a single patient with UC but not in any patients without UC.. Omission of epitope exposure enabled us to immunostain aggregated αSyn in the colon by pSyn#64 with low nonspecific staining, but the number of 23 UC patients was not high enough to discern whether abnormal αSyn aggregation in the colonic neural plexus was increased in UC or not.

Topics: alpha-Synuclein; Colitis, Ulcerative; Epitopes; Humans; Neurodegenerative Diseases; Paraffin; Parkinson Disease

Parkinson’s disease (PD) is a complex, chronic, and progressive neurodegenerative disease that is characterized by irreversible dopaminergic neuronal loss in the substantia nigra. Alpha-synuclein is normally a synaptic protein that plays a key role in PD due to pathological accumulation as oligomers or fibrils. Clustered alpha-synuclein binds to the Toll-like receptors and activates the microglia, which initiates a process that continues with pro-inflammatory cytokine production and secretion. Pro-inflammatory cytokine overproduction and secretion induce cell death and accelerate PD progression. Microglia are found in a resting state in physiological conditions. Microglia became activated by stimulating Toll-like receptors on it under pathological conditions, such as alpha-synuclein aggregation, environmental toxins, or oxidative stress. The interaction between Toll-like receptors and its downstream pathway triggers an activation series, leads to nuclear factor-kappa B activation, initiates the inflammasome formation, and increases cytokine levels. This consecutive inflammatory process leads to dopaminergic cell damage and cell death. Microglia become overactive in response to chronic inflammation, which is observed in PD and causes excessive cytotoxic factor production, such as reactive oxidase, nitric oxide, and tumor necrosis factor-alpha. This inflammatory process contributes to the exacerbation of pathology by triggering neuronal damage or death. Current treatments, such as dopaminergic agonists, anticholinergics, or monoamine oxidase inhibitors alleviate PD symptoms, but they can not stop the disease progression. Finding a radical treatment option or stopping the progression is essential when considering that PD is the second most reported neurodegenerative disorder. Many cytokines are released during inflammation, and they can start the phagocytic process, which caused the degradation of infected cells along with healthy ones. Therefore, targeting the pathological mechanisms, such as microglial activation, mitochondrial dysfunction, and oxidative stress, that should be involved in the treatment program is important. Neuroinflammation is one of the key factors involved in PD pathogenesis as well as alpha-synuclein accumulation, synaptic dysfunction, or dopaminergic neuronal loss, especially in the substantia nigra. Therefore, evaluating the therapeutic efficiency of the mechanisms is important, such as microglial activation and nuclear factor-kappa

Topics: alpha-Synuclein; Cytokines; Dopaminergic Neurons; Humans; Inflammasomes; Inflammation; Neurodegenerative Diseases; Neuroinflammatory Diseases; Parkinson Disease

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

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

Parkinson's disease (PD) is a neurodegenerative disease characterized by the accumulation of alpha-synuclein, encoded by the

Topics: alpha-Synuclein; Animals; Basal Ganglia; Glial Cell Line-Derived Neurotrophic Factor; Interneurons; Neurodegenerative Diseases; Parkinson Disease; Parvalbumins; Rats; Rats, Transgenic; Substantia Nigra

Several genetic models that recapitulate neurodegenerative features of Parkinson's disease (PD) exist, which have been largely based on genes discovered in monogenic PD families. However, spontaneous genetic mutations have not been linked to the pathological hallmarks of PD in non-human vertebrates.. To describe the genetic and pathological findings of three Yellow-crowned parrot (Amazona ochrocepahala) siblings with a severe and rapidly progressive neurological phenotype.. The phenotype of the three parrots included severe ataxia, rigidity, and tremor, while their parents were phenotypically normal. Tests to identify avian viral infections and brain imaging studies were all negative. Due to their severe impairment, they were all euthanized at age 3 months and their brains underwent neuropathological examination and proteasome activity assays. Whole genome sequencing (WGS) was performed on the three affected parrots and their parents.. The brains of affected parrots exhibited neuronal loss, spongiosis, and widespread Lewy body-like inclusions in many regions including the midbrain, basal ganglia, and neocortex. Proteasome activity was significantly reduced in these animals compared to a control (P < 0.05). WGS identified a single homozygous missense mutation (p.V559L) in a highly conserved amino acid within the pleckstrin homology (PH) domain of the calcium-dependent secretion activator 2 (CADPS2) gene.. Our data suggest that a homozygous mutation in the CADPS2 gene causes a severe neurodegenerative phenotype with Lewy body-like pathology in parrots. Although CADPS2 variants have not been reported to cause PD, further investigation of the gene might provide important insights into the pathophysiology of Lewy body disorders. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Topics: alpha-Synuclein; Animals; Carrier Proteins; Lewy Bodies; Mutation; Neurodegenerative Diseases; Parkinson Disease; Parrots; Proteasome Endopeptidase Complex

Parkinson's disease (PD) is a widely prevalent chronic neurodegenerative disease. The disease is characterized by loss of dopaminergic neurons with abnormal aggregation of α-synuclein (α-syn). The misfolded deposition of α-syn is known to mount robust adaptive immune response by activating T cells. Here, we show that peripheral mononuclear cells when stimulated with a α-syn-derived peptide pool activate α-syn-specific T cells that produce cytokines.

Topics: alpha-Synuclein; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Parkinson Disease; T-Lymphocytes

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

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

Amyloid aggregates of specific proteins constitute important pathological hallmarks in many neurodegenerative diseases, defining neuronal degeneration and disease onset. Recently, increasing numbers of patients show comorbidities and overlaps between multiple neurodegenerative diseases, presenting distinct phenotypes. Such overlaps are often accompanied by colocalizations of more than one amyloid protein, prompting the question of whether direct interactions between different amyloid proteins could generate heterotypic amyloids. To answer this question, we investigated the effect of α-synuclein (αS) on the DNA-binding protein TDP-43 aggregation inspired by their coexistence in pathologies such as Lewy body dementia and limbic predominant age-related TDP-43 encephalopathy. We previously showed αS and prion-like C-terminal domain (PrLD) of TDP-43 synergistically interact to generate toxic heterotypic aggregates. Here, we extend these studies to investigate whether αS induces structurally and functionally distinct polymorphs of PrLD aggregates. Using αS-PrLD heterotypic aggregates generated in two different stoichiometric proportions, we show αS can affect PrLD fibril forms. PrLD fibrils show distinctive residue level signatures determined by solid state NMR, dye-binding capability, proteinase K (PK) stability, and thermal stability toward SDS denaturation. Furthremore, by gold nanoparticle labeling and transmission electron microscopy, we show the presence of both αS and PrLD proteins within the same fibrils, confirming the existence of heterotypic amyloid fibrils. We also observe αS and PrLD colocalize in the cytosol of neuroblastoma cells and show that the heterotypic PrLD fibrils selectively induce synaptic dysfunction in primary neurons. These findings establish the existence of heterotypic amyloid and provide a molecular basis for the observed overlap between synucleinopathies and TDP-43 proteinopathies.

Topics: alpha-Synuclein; Amyloid; DNA-Binding Proteins; Gold; Humans; Metal Nanoparticles; Neurodegenerative Diseases; Neurotoxicity Syndromes

Parkinson's disease (PD) is a progressive neurodegenerative disease of both the central and peripheral / enteric nervous systems. Oxidative stress and neuroinflammation are associated with the pathogenesis of PD, suggesting that anti-oxidative and anti-inflammatory compounds could be neuroprotective agents for PD. Eucommia ulmoides (EU) is a traditional herbal medicine which exerts neuroprotective effects by anti-inflammatory and anti-oxidative properties. Our previous study showed that treatment with chlorogenic acid, a component of EU, protected against neurodegeneration in the central and enteric nervous systems in a PD model. In this study, we examined the effects of EU extract (EUE) administration on dopaminergic neurodegeneration, glial response and α-synuclein expression in the substantia nigra pars compacta (SNpc), and intestinal enteric neurodegeneration in low-dose rotenone-induced PD model mice. Daily oral administration of EUE ameliorated dopaminergic neurodegeneration and α-synuclein accumulation in the SNpc. EUE treatment inhibited rotenone-induced decreases in the number of total astrocytes and in those expressing the antioxidant molecule metallothionein. EUE also prevented rotenone-induced microglial activation. Furthermore, EUE treatment exerted protective effects against intestinal neuronal loss in the PD model. These results suggest that EU exerts neuroprotective effects in the central and enteric nervous systems of rotenone-induced parkinsonism mice, in part by glial modification.

Topics: alpha-Synuclein; Animals; Antioxidants; Chlorogenic Acid; Dopamine; Dopaminergic Neurons; Eucommiaceae; Metallothionein; Mice; Neurodegenerative Diseases; Neuroprotective Agents; Plant Extracts; Rotenone

Recently, the synaptic proteins neurogranin (Ng) and α-synuclein (α-Syn) have attracted scientific interest as potential biomarkers for synaptic dysfunction in neurodegenerative diseases. In this study, we measured the CSF Ng and α-Syn concentrations in patients affected by AD (n = 69), non-AD neurodegenerative disorders (n-AD = 50) and non-degenerative disorders (n-ND, n = 98). The concentrations of CSF Ng and α-Syn were significantly higher in AD than in n-AD and n-ND. Moreover, the Aβ42/Ng and Aβ42/α-Syn ratios showed statistically significant differences between groups and discriminated AD patients from n-AD patients, better than Ng or α-Syn alone. Regression analyses showed an association of higher Ng concentrations with MMSE < 24, pathological Aβ 42/40 ratios, pTau, tTau and the ApoEε4 genotype. Aβ 42/Ng was associated with MMSE < 24, an AD-related FDG-PET pattern, the ApoEε4 genotype, pathological Aβ 42 levels and Aβ 42/40 ratios, pTau, and tTau. Moreover, APO-Eε4 carriers showed higher Ng concentrations than non-carriers. Our results support the idea that the Aβ 42/Ng ratio is a reliable index of synaptic dysfunction/degeneration able to discriminate AD from other neurological conditions.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Cognitive Dysfunction; Fluorodeoxyglucose F18; Humans; Neurodegenerative Diseases; Neurogranin; tau Proteins

Parkinson's disease is the second most common age-related, neurodegenerative disease. A small collection of genes has been linked to Parkinson's disease including LRRK2, SAT1, and SNCA, the latter of which encodes the protein alpha-synuclein that aggregates in Lewy bodies as a hallmark of the disease. Overexpression of even wild-type versions of these genes can lead to pathogenesis, yet the regulatory mechanisms that control protein production of the genes are not fully understood. Pumilio proteins belong to the highly conserved PUF family of eukaryotic RNA-binding proteins that post-transcriptionally regulate gene expression through binding conserved motifs in the 3' untranslated region (UTR) of mRNA targets known as PUF Recognition Elements (PREs). The 3'UTRs of LRRK2, SNCA and SAT1 each contain multiple putative PREs. Knockdown (KD) of the two human Pumilio homologs (Pumilio 1 and Pumilio 2) in a neurodegenerative model cell line, SH-SY5Y, resulted in increased SNCA and LRRK2 mRNA, as well as alpha-synuclein levels, suggesting these genes are normally repressed by the Pumilio proteins. Some studies have indicated a relationship between Pumilio and microRNA activities on the same target, especially when their binding sites are close together. LRRK2, SNCA, and SAT1 each contain several putative microRNA-binding sites within the 3'UTR, some of which reside near PREs. Small RNA-seq and microRNA qPCR assays were performed in both wild type and Pumilio KD SH-SY5Y cells to analyze global and differential microRNA expression. One thousand four hundred and four microRNAs were detected across wild type and Pumilio KD cells. Twenty-one microRNAs were differentially expressed between treatments, six of which were previously established to be altered in Parkinson's disease patient samples or research models. Expression of ten miRs predicted to target LRRK2 and SNCA was verified by RT-qPCR. Collectively, our results demonstrate that Pumilios and microRNAs play a multi-faceted role in regulating Parkinson's disease-associated genes.

Topics: 3' Untranslated Regions; alpha-Synuclein; Humans; MicroRNAs; Neuroblastoma; Neurodegenerative Diseases; Parkinson Disease; RNA, Messenger

Olfactory impairment is a common symptom in Coronavirus Disease 2019 (COVID-19), the disease caused by Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) infection. While other viruses, such as influenza viruses, may affect the ability to smell, loss of olfactory function is often smoother and associated to various degrees of nasal symptoms. In COVID-19, smell loss may appear also in absence of other symptoms, frequently with a sudden onset. However, despite great clinical interest in COVID-19 olfactory alterations, very little is known concerning the mechanisms underlying these phenomena. Moreover, olfactory dysfunction is observed in neurological conditions like Parkinson's disease (PD) and can precede motor onset by many years, suggesting that viral infections, like COVID-19, and regional inflammatory responses may trigger defective protein aggregation and subsequent neurodegeneration, potentially linking COVID-19 olfactory impairment to neurodegeneration. In the following chapter, we report the neurobiological and neuropathological underpinnings of olfactory impairments encountered in COVID-19 and discuss the implications of these findings in the context of neurodegenerative disorders, with particular regard to PD and alpha-synuclein pathology.

Topics: alpha-Synuclein; COVID-19; Humans; Neurodegenerative Diseases; Olfaction Disorders; Parkinson Disease; Protein Aggregates; SARS-CoV-2; Smell

Parkinson's disease (PD) is a prevalent neurodegenerative disease for which robust biomarkers are needed. Because protein structure reflects function, we tested whether global, in situ analysis of protein structural changes provides insight into PD pathophysiology and could inform a new concept of structural disease biomarkers. Using limited proteolysis-mass spectrometry (LiP-MS), we identified 76 structurally altered proteins in cerebrospinal fluid (CSF) of individuals with PD relative to healthy donors. These proteins were enriched in processes misregulated in PD, and some proteins also showed structural changes in PD brain samples. CSF protein structural information outperformed abundance information in discriminating between healthy participants and those with PD and improved the discriminatory performance of CSF measures of the hallmark PD protein α-synuclein. We also present the first analysis of inter-individual variability of a structural proteome in healthy individuals, identifying biophysical features of variable protein regions. Although independent validation is needed, our data suggest that global analyses of the human structural proteome will guide the development of novel structural biomarkers of disease and enable hypothesis generation about underlying disease processes.

Topics: alpha-Synuclein; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease; Proteome

The misfolding and pathological aggregation of α-synuclein forming insoluble amyloid deposits is associated with Parkinson's disease, the second most common neurodegenerative disease in the world population. Characterizing the self-assembly mechanism of α-synuclein is critical for discovering treatments against synucleinopathies. The intrinsically disordered property, high degrees of freedom, and macroscopic timescales of conformational conversion make its characterization extremely challenging in vitro and in silico. Here, we systematically investigated the dynamics of monomer misfolding and dimerization of the full-length α-synuclein using atomistic discrete molecular dynamics simulations. Our results suggested that both α-synuclein monomers and dimers mainly adopted unstructured formations with partial helices around the N-terminus (residues 8-32) and various β-sheets spanning the residues 35-56 (N-terminal tail) and residues 61-95 (NAC region). The C-terminus mostly assumed an unstructured formation wrapping around the lateral surface and the elongation edge of the β-sheet core formed by an N-terminal tail and NAC regions. Dimerization enhanced the β-sheet formation along with a decrease in the unstructured content. The inter-peptide β-sheets were mainly formed by the N-terminal tail and NACore (residues 68-78) regions, suggesting that these two regions played critical roles in the amyloid aggregation of α-synuclein. Interactions of the C-terminus with the N-terminal tail and the NAC region were significantly suppressed in the α-synuclein dimer, indicating that the interaction of the C-terminus with the N-terminal tail and NAC regions could prevent α-synuclein aggregation. These results on the structural ensembles and early aggregation dynamics of α-synuclein will help understand the nucleation and fibrillization of α-synuclein.

Topics: alpha-Synuclein; Dimerization; Humans; Molecular Dynamics Simulation; Neurodegenerative Diseases; Protein Structure, Secondary

The synucleinopathies are neurodegenerative disease caused by abnormal accumulation of the 140-amino acid-containing protein α-synuclein (αSyn), including Parkinson's disease (PD), diffuse Lewy body dementia (DLBD), and multiple system atrophy (MSA). In patients with PD and DLBD, αSyn is misfolded in neurons, and its aggregation forms Lewy bodies (LB) and Lewy neurites (LN). On the other hand, in patients with MSA, αSyn accumulates primarily in oligodendrocytes (OLGs) and forms glial inclusion bodies (GCIs), a typical pathological feature of MSA. We recently demonstrated a making complex between αSyn and fatty acid-binding proteins (FABPs) in synucleinopathies and received wide attention. Fatty acid-binding protein 3 (FABP3) in dopamine nerves, and fatty acid-binding protein 7 (FABP7) in glial cells promoted αSyn accumulation and aggregation, respectively and caused cell death. Here, we introduced the current studies about the role of αSyn and FABP7 in MSA and novel therapeutic approach targeting for FABP7.

Topics: alpha-Synuclein; Fatty Acid-Binding Protein 7; Humans; Lewy Body Disease; Neurodegenerative Diseases; Parkinson Disease; Synucleinopathies

Several neurodegenerative pathologies can clinically mimic Parkinson's disease, including neurodegenerative diseases with glial pathology. However, the glial aggregates are typically composed of known pathogenic proteins and are associated with prominent neuronal loss in the substantia nigra. Here we present an unusual case of a 91-year-old man with a clinical diagnosis of Parkinson's disease, but whose autopsy findings showed a ubiquitin-positive astrogliopathy without significant neuronal loss in the substantia nigra. These glial aggregates affected the basal ganglia, cortex, and cerebellum, and were negative for tau, alpha-synuclein, TDP-43, FUS, and p62. This case is a rare example of an unknown glial neurodegenerative pathology mimicking Parkinson's disease without significant loss of nigral dopaminergic neurons.

Topics: Aged, 80 and over; alpha-Synuclein; Humans; Male; Neurodegenerative Diseases; Neuroglia; Parkinson Disease; Substantia Nigra; Ubiquitin

Topics: alpha-Synuclein; Antibodies, Monoclonal; Humans; Neurodegenerative Diseases; Parkinson Disease; Physicians

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

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

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

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

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

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

Parkinson's disease (PD) is a common neurodegenerative disease, yet fundamental treatments for the disease remain sparse. Thus, the search for potentially efficacious compounds from medicinal plants that can be used in the treatment of PD has gained significant interest.. In many medicinal plants, selenium is primarily found in an organic form. We investigated the neuroprotective potential of an organic form of selenium, N-γ-(L-glutamyl)-L-selenomethionine (Glu-SeMet) in a Caenorhabditis elegans PD model and its possible molecular mechanisms.. We used a C. elegans pharmacological PD strain (BZ555) that specifically expresses green fluorescent protein (GFP) in dopaminergic neurons and a transgenic PD strain (NL5901) that expresses human α-synuclein (α-syn) in muscle cells to investigate the neuroprotective potential of Glu-SeMet against PD.. We found that Glu-SeMet significantly ameliorated 6-hydroxydopamine (6-OHDA)-induced dopaminergic neuron damage in the transgenic BZ555 strain, with corresponding improvements in slowing behavior and intracellular ROS levels. In addition, compared with clinical PD drugs (L-DOPA and selegiline), Glu-SeMet demonstrated stronger ameliorated effects on 6-OHDA-induced toxicity. Glu-SeMet also triggered the nuclear translocation of SKN-1/Nrf2 and significantly increased SKN-1, GST-4, and GCS-1 mRNA levels in the BZ555 strain. However, Glu-SeMet did not increase mRNA levels or ameliorate the damage to dopaminergic neurons when the BZ555 strain was subjected to skn-1 RNA interference (RNAi). Glu-SeMet also upregulated the mRNA levels of the selenoprotein TRXR-1 in both the BZ555 and BZ555; skn-1 RNAi strains and significantly decreased α-syn accumulation in the NL5901 strain, although this was not observed in the NL5901; trxr-1 strain.. We found that Glu-SeMet has a neuroprotective effect against PD in a C. elegans PD model and that the anti-PD effects of Glu-SeMet were associated with SKN-1/Nrf2 and TRXR-1. Glu-SeMet may thus have the potential for use in therapeutic applications or supplements to slow the progression of PD.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; DNA-Binding Proteins; Dopaminergic Neurons; Humans; Neurodegenerative Diseases; Neuroprotective Agents; NF-E2-Related Factor 2; Parkinson Disease; Selenomethionine; Transcription Factors

Microglia play critical roles in the defense against neurodegenerative diseases. In this issue of Cell, Scheiblich et al. focus on microglia that ingest toxic aggregates of α-synuclein, finding that α-synuclein-replete microglia exchange aggregates for healthy mitochondria via nanotube connections to unaffected microglia. This communication enables a shared approach to aggregates disposal while preserving the health of the microglial population.

Topics: alpha-Synuclein; Fatty Acids, Omega-3; Humans; Microglia; Neurodegenerative Diseases

The trafficking of protein aggregates through neural circuitries causes adverse outcomes, including propagation of pathology and toxicity in neurodegenerative diseases. In a recent issue of Cell, Scheiblich et al. (2021) describe an advantageous aggregate-sharing strategy in microglial networks that nurtures α-synuclein-loaded members back to health.

Topics: alpha-Synuclein; Humans; Microglia; Neurodegenerative Diseases; Protein Aggregates

α-Synuclein is a key protein in the pathogenesis of Parkinson's disease as it accumulates in fibrillar form in affected brain regions. Misfolded α-synuclein seeds recruit monomeric α-synuclein to form aggregates, which can spread to anatomically connected brain regions, a phenomenon that correlates with clinical disease progression. Thus, downregulating α-synuclein levels could reduce seeding and inhibit aggregate formation and propagation. We previously reported that microRNA-7 (miR-7) protects neuronal cells by downregulating α-synuclein expression through its effect on the 3'-untranslated region of SNCA mRNA; however, whether miR-7 blocks α-synuclein seeding and propagation in vivo remains unknown. Here, we induced miR-7 overexpression in the mouse striatum unilaterally by infusing adeno-associated virus 1 (AAV-miR-7) followed by inoculation with recombinant α-synuclein preformed fibrils (PFF) a month later. Compared with control mice injected with non-targeting AAV-miR-NT followed by PFF, AAV-miR-7 pre-injected mice exhibited lower levels of monomeric and high-molecular-weight α-synuclein species in the striatum, and reduced amount of phosphorylated α-synuclein in the striatum and in nigral dopamine neurons. Accordingly, AAV-miR-7-injected mice had less pronounced degeneration of the nigrostriatal pathway and better behavioral performance. The neuroinflammatory reaction to α-synuclein PFF inoculation was also significantly attenuated. These data suggest that miR-7 inhibits the formation and propagation of pathological α-synuclein and protects against neurodegeneration induced by PFF. Collectively, these findings support the potential of miR-7 as a disease modifying biologic agent for Parkinson's disease and related α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Dopaminergic Neurons; Mice; MicroRNAs; Neurodegenerative Diseases; Synucleinopathies

Multiple factors are causally responsible and/or contribute to the progression of Alzheimer's and Parkinson's diseases. The protein kinase Dyrk1A was identified as a promising target as it phosphorylates tau protein, α-synuclein, and parkin. The first goal of our study was to optimize our previously identified Dyrk1A inhibitors of the 6-hydroxy benzothiazole urea chemotype in terms of potency and selectivity. Our efforts led to the development of the 3-fluorobenzyl amide derivative

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; tau Proteins; Urea

Exposure to heavy metals, including arsenic and cadmium, is associated with neurodegenerative disorders such as Parkinson's disease. However, the mechanistic details of how these metals contribute to pathogenesis are not well understood. To search for underlying mechanisms involving α-synuclein, the protein that forms amyloids in Parkinson's disease, we here assessed the effects of arsenic and cadmium on α-synuclein amyloid formation in vitro and in

Topics: alpha-Synuclein; Amyloid; Arsenites; Cadmium; Cell Line; Metals, Heavy; Neurodegenerative Diseases; Parkinson Disease; Saccharomyces cerevisiae

Peripheral administration (oral, intranasal, intraperitoneal, intravenous) of assembled A53T α-synuclein induced synucleinopathy in heterozygous mice transgenic for human mutant A53T α-synuclein (line M83). The same was the case when cerebellar extracts from a case of multiple system atrophy with type II α-synuclein filaments were administered intraperitoneally, intravenously or intramuscularly. We observed abundant immunoreactivity for pS129 α-synuclein in nerve cells and severe motor impairment, resulting in hindlimb paralysis and shortened lifespan. Filaments immunoreactive for pS129 α-synuclein were in evidence. A 70% loss of motor neurons was present five months after an intraperitoneal injection of assembled A53T α-synuclein or cerebellar extract with type II α-synuclein filaments from an individual with a neuropathologically confirmed diagnosis of multiple system atrophy. Microglial cells changed from a predominantly ramified to a dystrophic appearance. Taken together, these findings establish a close relationship between the formation of α-synuclein inclusions in nerve cells and neurodegeneration, accompanied by a shift in microglial cell morphology. Propagation of α-synuclein inclusions depended on the characteristics of both seeds and transgenically expressed protein.

Topics: Aged; alpha-Synuclein; Animals; Animals, Genetically Modified; Hindlimb; Humans; Immunohistochemistry; Male; Mice, Neurologic Mutants; Microglia; Motor Neurons; Movement Disorders; Multiple System Atrophy; Mutation; Neurodegenerative Diseases; Neurons; Paralysis

Parkinson's disease (PD) is the second most common neurodegenerative disorder. An important hallmark of PD involves the pathological aggregation of proteins in structures known as Lewy bodies. The major component of these proteinaceous inclusions is alpha (α)-synuclein. In different conditions, α-synuclein can assume conformations rich in either α-helix or β-sheets. The mechanisms of α-synuclein misfolding, aggregation, and fibrillation remain unknown, but it is thought that β-sheet conformation of α-synuclein is responsible for its associated toxic mechanisms. To gain fundamental insights into the process of α-synuclein misfolding and aggregation, the secondary structure of this protein in the presence of charged and non-charged surfactant solutions was characterized. The selected surfactants were (anionic) sodium dodecyl sulphate (SDS), (cationic) cetyltrimethylammonium chloride (CTAC), and (uncharged) octyl β-D-glucopyranoside (OG). The effect of surfactants in α-synuclein misfolding was assessed by ultra-structural analyses, in vitro aggregation assays, and secondary structure analyses. The α-synuclein aggregation in the presence of negatively charged SDS suggests that SDS-monomer complexes stimulate the aggregation process. A reduction in the electrostatic repulsion between N- and C-terminal and in the hydrophobic interactions between the NAC (non-amyloid beta component) region and the C-terminal seems to be important to undergo aggregation. Fourier transform infrared spectroscopy (FTIR) measurements show that β-sheet structures comprise the assembly of the fibrils.

Topics: alpha-Synuclein; Amyloid; Cetrimonium; Circular Dichroism; Galactosides; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregation, Pathological; Protein Conformation; Protein Conformation, beta-Strand; Protein Folding; Protein Structure, Secondary; Sodium Dodecyl Sulfate; Spectroscopy, Fourier Transform Infrared

CNS pathological inclusions comprising τ or α-synuclein (αSyn) define a spectrum of neurodegenerative diseases, and these can often present concurrently in the same individuals. The aggregation of both proteins is clearly associated with neurodegeneration and the deleterious properties of each protein is further supported by mutations in each gene (MAPT and SNCA, respectively) resulting in disease. The initiating events in most sporadic neurodegenerative diseases are still unclear but growing evidence suggests that the aberrant proteolytic cleavage of τ and αSyn results in products that can be toxic and/or initiate aggregation that can further spread by a prion-like mechanism. The accumulation of some of these cleavage products can further potentiate the progression of protein aggregation transmission and lead to their accumulation in peripheral biofluids such as cerebrospinal fluid (CSF) and blood. The future development of new tools to detect specific τ and αSyn abnormal cleavage products in peripheral biofluids could be useful biomarkers and better understand of the role of unique proteolytic activities could yield therapeutic interventions.

Topics: alpha-Synuclein; Gene Expression; Humans; Neurodegenerative Diseases; Prions; Proteolysis; tau Proteins

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopamine neurons and the deposition of misfolded proteins known as Lewy bodies (LBs), which contain α-synuclein (α-syn). The causes and molecular mechanisms of PD are not clearly understood to date. However, misfolded proteins, oxidative stress, and impaired autophagy are believed to play important roles in the pathogenesis of PD. Importantly, α-syn is considered a key player in the development of PD. The present study aimed to assess the role of Ellagic acid (EA), a polyphenol found in many fruits, on α-syn aggregation and toxicity. Using thioflavin and seeding polymerization assays, in addition to electron microscopy, we found that EA could dramatically reduce α-syn aggregation. Moreover, EA significantly mitigated the aggregated α-syn-induced toxicity in SH-SY5Y cells and thus enhanced their viability. Mechanistically, these cytoprotective effects of EA are mediated by the suppression of apoptotic proteins BAX and p53 and a concomitant increase in the anti-apoptotic protein, BCL-2. Interestingly, EA was able to activate autophagy in SH-SY5Y cells, as evidenced by normalized/enhanced expression of LC3-II, p62, and pAKT. Together, our findings suggest that EA may attenuate α-syn toxicity by preventing aggregation and improving viability by restoring autophagy and suppressing apoptosis.

Topics: alpha-Synuclein; Apoptosis; Autophagy; Cell Line, Tumor; Dopaminergic Neurons; Ellagic Acid; Humans; Lewy Bodies; Neurodegenerative Diseases; Parkinson Disease; Protein Aggregates; Protein Aggregation, Pathological

Topics: alpha-Synuclein; Animals; Brain; Brain Ischemia; Down-Regulation; Endosomes; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Models, Animal; Nedd4 Ubiquitin Protein Ligases; Neurodegenerative Diseases; Neurons; Neuroprotection; Parkinson Disease; Protein Aggregation, Pathological; Protein Processing, Post-Translational; Stroke; Ubiquitin-Protein Ligases; Ubiquitination; Up-Regulation

The olfactory bulb (OB) seems to be the first affected structure in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and Lewy body dementia (LBD). Deposits of protein aggregates, increased dopaminergic neurons, and decreased cholinergic inputs have all been described in the OB of these diseases. We investigated here the contribution of the activated microglial cells to the increased deposits of protein aggregates. We quantified the number of activated microglial cells and astrocytes in the OB of patients with histological diagnosis of PD (n = 5), AD (n = 13), and LBD (n = 7) and aged-matched controls (n = 8). Specific consensus diagnostic criteria were applied for AD, LBD, and PD. Protein aggregates were scored in the OB as grade 0, none; grade 1, mild; grade 2, moderate; and grade 3, severe. OB sections from the 33 subjects were stained with specific antibodies markers for reactive astrocytes (GFAP) and microglial cells (Iba1 and HLA-DR). The total number of Iba1-ir (Iba-immunoreactive) and HLAD-DR cells was estimated by stereological analysis, while quantification of astrocytes was performed by GFAP optical density. Statistical analysis was done using the Stata 12.0 software. The number of microglia and activated microglia cells (HLA-RD-ir) was increased in patients with neurodegenerative diseases (p < 0.05). Moreover, the density of GFAP-ir cells was higher in the OB of patients. Neither the number of microglia cells nor the density of astrocytes correlated with the number of b-amyloid and alpha-synuclein deposits, but the density of Iba1-ir cells correlated with the number of p-Tau aggregates. Activated microglial cells and reactive astrocytes are present in the OB of patients with neurodegenerative diseases. The lack of correlation between the number of activated microglia cells and protein deposits indicate that they might independently contribute to the degenerative process. The presence of microglia is related to phosphorylated Tau deposits in neurodegenerative diseases.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Humans; Lewy Body Disease; Microglia; Neurodegenerative Diseases; Olfactory Bulb

Deposition of misfolded alpha-synuclein (αSYN) aggregates in the human brain is one of the major hallmarks of synucleinopathies. However, a target-specific tracer to detect pathological aggregates of αSYN remains lacking. Here, we report the development of a positron emission tomography (PET) tracer based on anle138b, a compound shown to have therapeutic activity in animal models of neurodegenerative diseases.. Specificity and selectivity of [. [. MODAG-001 provides a promising lead structure for future compound development as it combines a high affinity and good selectivity in fibril-binding assays with suitable pharmacokinetics and biodistribution properties.

Topics: alpha-Synuclein; Animals; Carbon Radioisotopes; Lewy Body Disease; Mice; Neurodegenerative Diseases; Positron-Emission Tomography; Radiopharmaceuticals; Rats; Tissue Distribution

The conventional notions of pseudogenes being 'junk DNA' have largely been offset as research studies have established their role in multiple biological processes. Our studies towards identification of genetic modulators employing C. elegans model, that associate reproductive health and age-related neurodegenerative diseases, led us to identification and functional characterization of a pseudogene T04B2.1, which when knocked down, exacerbates the aggregation of α-Synuclein and β-Amyloid proteins, induces lipid deposition and alters morphometric endpoints in worms. Whole transcriptome analysis of worms under knockdown condition of T04B2.1 revealed an altered expression of 187 sequences, most of these being non-coding RNAs, miRNAs and piRNAs modulating the RNAi regulatory processes. Our gene ontology and pathway enrichment analysis demonstrated the role of T04B2.1 in protein quality control, metabolic pathways and development. We further performed a signature motif search and successfully identified a common motif that is present between all piRNA and miRNA molecules, which are significantly altered upon T04B2.1 silencing. This study unveils the non-conventional regulatory role of pseudogene T04B2.1 with respect to effects associated with neurodegenerative diseases and encourages further studies to decipher the regulatory mechanism governed by pseudogenes.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Gene Expression Profiling; Gene Expression Regulation; Gene Ontology; Gene Silencing; Neurodegenerative Diseases; Pseudogenes

Topics: alpha-Synuclein; Animals; Astrocytes; Cells, Cultured; Female; Glutamic Acid; Hippocampus; Humans; Induced Pluripotent Stem Cells; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Synapses

Mouse models have allowed for the direct interrogation of genetic effects on molecular, physiological, and behavioral brain phenotypes. However, it is unknown to what extent neurological or psychiatric traits may be human- or primate-specific and therefore which components can be faithfully recapitulated in mouse models.. We compare conservation of co-expression in 116 independent data sets derived from human, mouse, and non-human primate representing more than 15,000 total samples. We observe greater changes occurring on the human lineage than mouse, and substantial regional variation that highlights cerebral cortex as the most diverged region. Glia, notably microglia, astrocytes, and oligodendrocytes are the most divergent cell type, three times more on average than neurons. We show that cis-regulatory sequence divergence explains a significant fraction of co-expression divergence. Moreover, protein coding sequence constraint parallels co-expression conservation, such that genes with loss of function intolerance are enriched in neuronal, rather than glial modules. We identify dozens of human neuropsychiatric and neurodegenerative disease risk genes, such as COMT, PSEN-1, LRRK2, SHANK3, and SNCA, with highly divergent co-expression between mouse and human and show that 3D human brain organoids recapitulate in vivo co-expression modules representing several human cell types.. We identify robust co-expression modules reflecting whole-brain and regional patterns of gene expression. Compared with those that represent basic metabolic processes, cell-type-specific modules, most prominently glial modules, are the most divergent between species. These data and analyses serve as a foundational resource to guide human disease modeling and its interpretation.

Topics: alpha-Synuclein; Animals; Astrocytes; Brain; Catechol O-Methyltransferase; Cerebral Cortex; Evolution, Molecular; Gene Expression Profiling; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Mice; Microfilament Proteins; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Presenilin-1; Primates; Transcriptome

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

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

The development of disease-modifying therapies for Parkinson's disease is a major challenge which would be facilitated by a better understanding of the pathogenesis. Leucine-rich repeat kinase 2 (LRRK2) and α-synuclein are key players in Parkinson's disease, but their relationship remains incompletely resolved. Previous studies investigating the effect of LRRK2 on α-synuclein-induced neurotoxicity and neuroinflammation in preclinical Parkinson's disease models have reported conflicting results. Here, we aimed to further explore the functional interaction between α-synuclein and LRRK2 and to evaluate the therapeutic potential of targeting physiological LRRK2 levels. We studied the effects of total LRRK2 protein loss as well as pharmacological LRRK2 kinase inhibition in viral vector-mediated α-synuclein-based Parkinson's disease models developing early- and late-stage neurodegeneration. Surprisingly, total LRRK2 ablation or in-diet treatment with the LRRK2 kinase inhibitor MLi-2 did not significantly modify α-synuclein-induced motor deficits, dopaminergic cell loss, or α-synuclein pathology. Interestingly, we found a significant effect on α-synuclein-induced neuroinflammatory changes in the absence of LRRK2, with a reduced microglial activation and CD4

Topics: alpha-Synuclein; Animals; Indazoles; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Neurodegenerative Diseases; Neuroinflammatory Diseases; Pyrimidines; Rats; Rats, Long-Evans; Rats, Transgenic

Parkinson's disease (PD) is an age-related neurodegenerative disease (NDD) characterized by the degenerative loss of dopaminergic neurons in the substantia nigra along with aggregation of α-synuclein (α-syn). Neurogenic differentiation of human adipose-derived stem cells (NI-hADSCs) by supplementary factors for 14 days activates different biological signaling pathways. In this study, we evaluated the therapeutic role of NI-hADSC-conditioned medium (NI-hADSC-CM) in rotenone (ROT)-induced toxicity in SH-SY5Y cells. Increasing concentrations of ROT led to decreased cell survival at 24 and 48 h in a dose- and time-dependent manner. Treatment of NI-hADSC-CM (50% dilution in DMEM) against ROT (0.5 μM) significantly increased the cell survival. ROT toxicity decreased the expression of tyrosine hydroxylase (TH). Western blot analysis of the Triton X-100-soluble fraction revealed that ROT significantly decreased the oligomeric, dimeric, and monomeric phosphorylated Serine129 (p-S129) α-syn, as well as the total monomeric α-syn expression levels. ROT toxicity increased the oligomeric, but decreased the dimeric and monomeric p-S129 α-syn expression levels. Total α-syn expression (in all forms) was increased in the Triton X-100-insoluble fraction, compared to the control. NI-hADSC-CM treatment enhanced the TH expression, stabilized α-syn monomers, reduced the levels of toxic insoluble p-S129 α-syn, improved the expression of neuronal functional proteins, regulated the Bax/Bcl-2 ratio, and upregulated the expression of pro-caspases, along with PARP-1 inactivation. Moreover, hADSC-CM treatment decreased the cell numbers and have no effect against ROT toxicity on SH-SY5Y cells. The therapeutic effects of NI-hADSC-CM was higher than the beneficial effects of hADSC-CM on cellular signaling. From these results, we conclude that NI-hADSC-CM exerts neuroregenerative effects on ROT-induced PD-like impairments in SH-SY5Y cells.

Topics: Adipose Tissue; alpha-Synuclein; bcl-2-Associated X Protein; Culture Media, Conditioned; Humans; Neurodegenerative Diseases; Neurons; Poly (ADP-Ribose) Polymerase-1; Proto-Oncogene Proteins c-bcl-2; Rotenone; Signal Transduction; Stem Cells

Parkinson's disease is a neurodegenerative disorder associated with misfolding and aggregation of α-synuclein as a hallmark protein. Two yeast strain collections comprising conditional alleles of essential genes were screened for the ability of each allele to reduce or improve yeast growth upon α-synuclein expression. The resulting 98 novel modulators of α-synuclein toxicity clustered in several major categories including transcription, rRNA processing and ribosome biogenesis, RNA metabolism and protein degradation. Furthermore, expression of α-synuclein caused alterations in pre-rRNA transcript levels in yeast and in human cells. We identified the nucleolar DEAD-box helicase Dbp4 as a prominent modulator of α-synuclein toxicity. Downregulation of DBP4 rescued cells from α-synuclein toxicity, whereas overexpression led to a synthetic lethal phenotype. We discovered that α-synuclein interacts with Dbp4 or its human ortholog DDX10, sequesters the protein outside the nucleolus in yeast and in human cells, and stabilizes a fraction of α-synuclein oligomeric species. These findings provide a novel link between nucleolar processes and α-synuclein mediated toxicity with DDX10 emerging as a promising drug target.

Topics: alpha-Synuclein; Amyloid; DEAD-box RNA Helicases; Gene Expression Regulation; Humans; Inclusion Bodies; Models, Biological; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; Protein Binding; Protein Multimerization; Protein Transport; Yeasts

No disease-modifying therapy is currently available for Parkinson's disease (PD), the second most common neurodegenerative disease. The long nonmotor prodromal phase of PD is a window of opportunity for early detection and intervention. However, we lack the pathophysiological understanding to develop selective biomarkers and interventions. By using a mutant α-synuclein selective-overexpression mouse model of prodromal PD, we identified a cell-autonomous selective Kv4 channelopathy in dorsal motor nucleus of the vagus (DMV) neurons. This functional remodeling of intact DMV neurons leads to impaired pacemaker function in vitro and in vivo, which, in turn, reduces gastrointestinal motility, a common early symptom of prodromal PD. We identify a chain of events from α-synuclein via a biophysical dysfunction of a specific neuronal population to a clinically relevant prodromal symptom. These findings will facilitate the rational design of clinical biomarkers to identify people at risk for developing PD.

Topics: alpha-Synuclein; Animals; Channelopathies; Humans; Mice; Motor Neurons; Neurodegenerative Diseases; Parkinson Disease

Intracellular aggregates are a common pathological hallmark of neurodegenerative diseases such as polyglutamine (polyQ) diseases, amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and multiple system atrophy (MSA). Aggregates are mainly formed by aberrant disease-specific proteins and are accompanied by accumulation of other aggregate-interacting proteins. Although aggregate-interacting proteins have been considered to modulate the formation of aggregates and to be involved in molecular mechanisms of disease progression, the components of aggregate-interacting proteins remain unknown. In this study, we showed that small glutamine-rich tetratricopeptide repeat-containing protein alfa (SGTA) is an aggregate-interacting protein in neurodegenerative diseases. Immunohistochemistry showed that SGTA interacted with intracellular aggregates in Huntington disease (HD) cell models and neurons of HD model mice. We also revealed that SGTA colocalized with intracellular aggregates in postmortem brains of patients with polyQ diseases including spinocerebellar ataxia (SCA)1, SCA2, SCA3, and dentatorubral-pallidoluysian atrophy. In addition, SGTA colocalized with glial cytoplasmic inclusions in the brains of MSA patients, whereas no accumulation of SGTA was observed in neurons of PD and ALS patients. In vitro study showed that SGTA bound to polyQ aggregates through its C-terminal domain and SGTA overexpression reduced intracellular aggregates. These results suggest that SGTA may play a role in the formation of aggregates and may act as potential modifier of molecular pathological mechanisms of polyQ diseases and MSA.

Topics: alpha-Synuclein; Animals; Autopsy; Brain; Brain Chemistry; Cell Line, Tumor; Humans; Huntingtin Protein; Inclusion Bodies; Mice; Mice, Transgenic; Molecular Chaperones; Nerve Tissue Proteins; Neuroblastoma; Neurodegenerative Diseases; Peptide Fragments; Peptides; Protein Aggregates; Protein Aggregation, Pathological; Recombinant Proteins; Solubility; Subcellular Fractions; Transfection

The post-infection of COVID-19 includes a myriad of neurologic symptoms including neurodegeneration. Protein aggregation in brain can be considered as one of the important reasons behind the neurodegeneration. SARS-CoV-2 Spike S1 protein receptor binding domain (SARS-CoV-2 S1 RBD) binds to heparin and heparin binding proteins. Moreover, heparin binding accelerates the aggregation of the pathological amyloid proteins present in the brain. In this paper, we have shown that the SARS-CoV-2 S1 RBD binds to a number of aggregation-prone, heparin binding proteins including Aβ, α-synuclein, tau, prion, and TDP-43 RRM. These interactions suggests that the heparin-binding site on the S1 protein might assist the binding of amyloid proteins to the viral surface and thus could initiate aggregation of these proteins and finally leads to neurodegeneration in brain. The results will help us to prevent future outcomes of neurodegeneration by targeting this binding and aggregation process.

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Brain; COVID-19; DNA-Binding Proteins; Heparin; Humans; Molecular Docking Simulation; Neurodegenerative Diseases; Prions; Protein Aggregation, Pathological; Protein Binding; SARS-CoV-2; Spike Glycoprotein, Coronavirus; tau Proteins

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

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

Protein misfolding diseases refer to a variety of disorders that develop as a consequence of the misfolding of proteins in various organs. The etiologies of Parkinson's and Alzheimer's disease remain unclear, but it seems that type two diabetes and other prediabetic states could contribute to the appearance of the sporadic forms of these diseases. In addition to amylin deposition, other amyloidogenic proteins implicated in the pathophysiology of neurodegenerative diseases could have important roles in the pathogenesis of this disease. As we have previously demonstrated the presence of α-synuclein deposits in the pancreas of patients with synucleinopathies, as well as tau and Aβ deposits in the pancreatic tissue of Alzheimer's disease patients, we studied the immunoreactivity of amylin, tau and α-synuclein in the pancreas of 138 subjects with neurodegenerative diseases or type two diabetes and assessed whether the pancreatic β-cells of these subjects present cooccurrence of misfolded proteins. Furthermore, we also assessed the pancreatic expression of prion protein (PrP) in these subjects and its interaction, both in the pancreas and brain, with α-synuclein, tau, Aβ and amylin. Our study shows, for the first time, that along with amylin, pancreatic α-synuclein, Aβ, PrP and tau may contribute together to the complex pathophysiology of type two diabetes and in the appearance of insulin resistance in Alzheimer's and Parkinson's disease. Furthermore, we show that the same mixed pathologies that are observed in the brains of patients with neurodegenerative diseases are also present outside the nervous system. Finally, we provide the first histological evidence of an interaction between PrP and Aβ, α-synuclein, amylin or tau in the pancreas and locus coeruleus. These findings will shed more light on the common pathological pathways shared by neurodegenerative diseases and type two diabetes, benefiting the exploration of common therapeutic strategies to prevent or treat these devastating amyloid diseases.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Brain; Diabetes Mellitus, Type 2; Female; Humans; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Male; Neurodegenerative Diseases; Prion Proteins; Retrospective Studies; tau Proteins

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. Nitrated α-synuclein (α-syn) in the blood is a potentially efficient biomarker for PD in its early stages. In this work, an ultrasensitive electrochemical immunosensor was developed for the specific detection of nitrated α-syn. Supramolecule-mediated AuNP composites (GNCs) were modified on the gold electrode as a sensing film to capture anti-nitrated α-syn. Basic characterization studies revealed that GNCs were composed of abundant binding sites and had high conductivity with a large surface area, biocompatibility, and remarkable electrochemical activity. Anti-α-syn-modified magnetic nanoparticles (MNPs) were used as signal amplification tags to construct a sensitive sandwich assay. With a high specific surface area, strong conductivity, and abundant active sites, GNCs as an amplifying matrix can enhance the performance of the immunoassay and obtain preliminary signal amplification. MNPs showed excellent stability and led to a net decrease in the charge-transfer resistance due to their unique spherical structure and high conductivity, resulting in a sensitive electrochemical signal change according to the nitrated α-syn concentration in the sample. Therefore, this simple nitrated α-syn immunoassay with sensitivity and selectivity has potential for practical clinical applications.

Topics: alpha-Synuclein; Biosensing Techniques; Electrochemical Techniques; Gold; Humans; Immunoassay; Limit of Detection; Magnetic Phenomena; Metal Nanoparticles; Neurodegenerative Diseases; Nitrates

Pathology consisting of intracellular aggregates of alpha-Synuclein (α-Syn) spread through the nervous system in a variety of neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. The discovery of structurally distinct α-Syn polymorphs, so-called strains, supports a hypothesis where strain-specific structures are templated into aggregates formed by native α-Syn. These distinct strains are hypothesised to dictate the spreading of pathology in the tissue and the cellular impact of the aggregates, thereby contributing to the variety of clinical phenotypes. Here, we present evidence of a novel α-Syn strain induced by the multiple system atrophy-associated oligodendroglial protein p25α. Using an array of biophysical, biochemical, cellular, and in vivo analyses, we demonstrate that compared to α-Syn alone, a substoichiometric concentration of p25α redirects α-Syn aggregation into a unique α-Syn/p25α strain with a different structure and enhanced in vivo prodegenerative properties. The α-Syn/p25α strain induced larger inclusions in human dopaminergic neurons. In vivo, intramuscular injection of preformed fibrils (PFF) of the α-Syn/p25α strain compared to α-Syn PFF resulted in a shortened life span and a distinct anatomical distribution of inclusion pathology in the brain of a human A53T transgenic (line M83) mouse. Investigation of α-Syn aggregates in brain stem extracts of end-stage mice demonstrated that the more aggressive phenotype of the α-Syn/p25α strain was associated with an increased load of α-Syn aggregates based on a Förster resonance energy transfer immunoassay and a reduced α-Syn aggregate seeding activity based on a protein misfolding cyclic amplification assay. When injected unilaterally into the striata of wild-type mice, the α-Syn/p25α strain resulted in a more-pronounced motoric phenotype than α-Syn PFF and exhibited a "tropism" for nigro-striatal neurons compared to α-Syn PFF. Overall, our data support a hypothesis whereby oligodendroglial p25α is responsible for generating a highly prodegenerative α-Syn strain in multiple system atrophy.

Topics: alpha-Synuclein; Animals; Cell Line; Humans; Inclusion Bodies; Mice; Mice, Transgenic; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Oligodendroglia; Protein Conformation; Proteostasis Deficiencies; Substantia Nigra; Synucleinopathies

Parkinson's disease (PD) is the most prevalent movement disorder known and predominantly affects the elderly. It is a progressive neurodegenerative disease wherein α-synuclein, a neuronal protein, aggregates to form toxic structures in nerve cells. The cause of Parkinson's disease (PD) remains unknown. Intestinal dysfunction and changes in the gut microbiota, common symptoms of PD, are evidently linked to the pathogenesis of PD. Although a multitude of studies have investigated microbial etiologies of PD, the microbial role in disease progression remains unclear. Here, we show that Gram-negative sulfate-reducing bacteria of the genus

Topics: Aged; alpha-Synuclein; Bacteria; Desulfovibrio; Humans; Neurodegenerative Diseases; Parkinson Disease

Late-life cognitive function is heterogeneous, ranging from no decline to severe dementia. Prior studies of cognitive trajectories have tended to focus on a single measure of global cognition or individual tests scores, rather than considering longitudinal performance on multiple tests simultaneously.. The current study aimed to examine cognitive trajectories from two independent datasets to assess whether similar patterns might describe longitudinal cognition in the decade preceding death, as well as what participant characteristics were associated with trajectory membership.. Data were drawn from autopsied longitudinally followed participants of two cohorts (total N = 1,346), community-based cohort at the University of Kentucky Alzheimer's Disease Research Center (n = 365) and National Alzheimer's Coordinating Center (n = 981). We used group-based multi-trajectory models (GBMTM) to identify cognitive trajectories over the decade before death using Mini-Mental State Exam, Logical Memory-Immediate, and Animal Naming performance. Multinomial logistic and Random Forest analyses assessed characteristics associated with trajectory groups.. GBMTM identified four similar cognitive trajectories in each dataset. In multinomial models, death age, Braak neurofibrillary tangles (NFT) stage, TDP-43, and α-synuclein were associated with declining trajectories. Random Forest results suggested the most important trajectory predictors were Braak NFT stage, cerebral atrophy, death age, and brain weight. Multiple pathologies were most common in trajectories with moderate or accelerated decline.. Cognitive trajectories associated strongly with neuropathology, particularly Braak NFT stage. High frequency of multiple pathologies in trajectories with cognitive decline suggests dementia treatment and prevention efforts must consider multiple diseases simultaneously.

Topics: Age Factors; Aged; Aging; alpha-Synuclein; Alzheimer Disease; Atrophy; Autopsy; Brain; Cognition; Cognitive Dysfunction; Disease Progression; Female; Humans; Longitudinal Studies; Male; Neurodegenerative Diseases; Neurofibrillary Tangles; Neuropsychological Tests; Organ Size

Epigenetic modifications in neurodegenerative disease are under investigation for their roles in disease progression. Alterations in acetylation rates of certain Parkinson's disease (PD)-linked genes have been associated with the pathological progression of this disorder. In light of this, and given the lack of disease-modifying therapies for PD, HDAC inhibitors (HDIs) are under consideration as potential pharmacological agents. The neuroprotective effects of pan-HDACs and some class-specific inhibitors have been tested in in vivo and in vitro models of PD, with varying outcomes. Here we used gene co-expression analysis to identify HDACs that are associated with human dopaminergic (DA) neuron development. We identified HDAC3, HDAC5, HDAC6 and HDAC9 as being highly correlated with the DA markers, SLC6A3 and NR4A2. RT-qPCR revealed that mRNA expression of these HDACs exhibited similar temporal profiles during embryonic mouse midbrain DA (mDA) neuron development. We tested the neuroprotective potential of a number of class-specific small molecule HDIs on human SH-SY5Y cells, using neurite growth as a phenotypic readout of neurotrophic action. Neither the class I-specific HDIs, RGFP109 and RGFP966, nor the HDAC6 inhibitor ACY1215, had significant effects on neurite outgrowth. However, the class IIa HDI, LMK235 (a HDAC4/5 inhibitor), significantly increased histone acetylation and neurite outgrowth. We found that LMK235 increased BMP-Smad-dependent transcription in SH-SY5Y cells and that this was required for its neurite growth-promoting effects on SH-SY5Y cells and on DA neurons in primary cultures of embryonic day (E) 14 rat ventral mesencephalon (VM). These effects were also seen in SH-SY5Y cells transfected with HDAC5 siRNA. Furthermore, LMK235 treatment exerted neuroprotective effects against degeneration induced by the DA neurotoxin 1-methyl-4-phenylpyridinium (MPP

Topics: alpha-Synuclein; Animals; Dopaminergic Neurons; Histone Deacetylases; Mice; Neurodegenerative Diseases; Neurotoxins; Parkinson Disease; Rats

Abnormal accumulation of acrolein, an α, β unsaturated aldehyde has been reported as one pathological cause of the CNS neurodegenerative diseases. In the present study, the neuroprotective effect of selumetinib (a MEK-ERK inhibitor) on acrolein-induced neurotoxicity was investigated in vitro using primary cultured cortical neurons. Incubation of acrolein consistently increased phosphorylated ERK levels. Co-treatment of selumetinib blocked acrolein-induced ERK phosphorylation. Furthermore, selumetinib reduced acrolein-induced increases in heme oxygenase-1 (a redox-regulated chaperone protein) and its transcriptional factor, Nrf-2 as well as FDP-lysine (acrolein-lysine adducts) and α-synuclein aggregation (a pathological biomarker of neurodegeneration). Morphologically, selumetinib attenuated acrolein-induced damage in neurite outgrowth, including neuritic beading and neurite discontinuation. Moreover, selumetinib prevented acrolein-induced programmed cell death via decreasing active caspase 3 (a hallmark of apoptosis) as well as RIP (receptor-interacting protein) 1 and RIP3 (biomarkers for necroptosis). In conclusion, our study showed that selumetinib inhibited acrolein-activated Nrf-2-HO-1 pathway, acrolein-induced protein conjugation and aggregation as well as damage in neurite outgrowth and cell death, suggesting that selumetinib, a MEK-ERK inhibitor, may be a potential neuroprotective agent against acrolein-induced neurotoxicity in the CNS neurodegenerative diseases.

Topics: Acrolein; alpha-Synuclein; Animals; Apoptosis; Benzimidazoles; Cells, Cultured; Cerebral Cortex; Humans; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase Kinases; Necroptosis; Neurodegenerative Diseases; Neuronal Outgrowth; Neurons; Neuroprotective Agents; Primary Cell Culture; Protein Aggregates; Rats; Toxicity Tests, Acute

Liquid-liquid phase separation (LLPS) has emerged as a key mechanism for intracellular organization, and many recent studies have provided important insights into the role of LLPS in cell biology. There is also evidence that LLPS is associated with a variety of medical conditions, including neurodegenerative disorders. Pathological aggregation of α-synuclein, which is causally linked to Parkinson's disease, can proceed via droplet condensation, which then gradually transitions to the amyloid state. We show that the antimicrobial peptide LL-III is able to interact with both monomers and condensates of α-synuclein, leading to stabilization of the droplet and preventing conversion to the fibrillar state. The anti-aggregation activity of LL-III was also confirmed in a cellular model. We anticipate that studying the interaction of antimicrobial-type peptides with liquid condensates such as α-synuclein will contribute to the understanding of disease mechanisms (that arise in such condensates) and may also open up exciting new avenues for intervention.

Topics: alpha-Synuclein; Amyloid; Humans; Neurodegenerative Diseases; Parkinson Disease; Pore Forming Cytotoxic Proteins

The medial temporal lobe (MTL) is a nidus for neurodegenerative pathologies and therefore an important region in which to study polypathology. We investigated associations between neurodegenerative pathologies and the thickness of different MTL subregions measured using high-resolution post-mortem MRI. Tau, TAR DNA-binding protein 43 (TDP-43), amyloid-β and α-synuclein pathology were rated on a scale of 0 (absent)-3 (severe) in the hippocampus and entorhinal cortex (ERC) of 58 individuals with and without neurodegenerative diseases (median age 75.0 years, 60.3% male). Thickness measurements in ERC, Brodmann Area (BA) 35 and 36, parahippocampal cortex, subiculum, cornu ammonis (CA)1 and the stratum radiatum lacunosum moleculare (SRLM) were derived from 0.2 × 0.2 × 0.2 mm

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Brain Cortical Thickness; CA1 Region, Hippocampal; Case-Control Studies; DNA-Binding Proteins; Entorhinal Cortex; Female; Frontotemporal Lobar Degeneration; Hippocampus; Humans; Lewy Body Disease; Magnetic Resonance Imaging; Male; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; Parahippocampal Gyrus; Pick Disease of the Brain; Plaque, Amyloid; Supranuclear Palsy, Progressive; tau Proteins; Temporal Lobe

The clinical validation and qualification of biomarkers reflecting the complex pathophysiology of neurodegenerative diseases (NDDs) is a fundamental challenge for current drug discovery and development and next-generation clinical practice. Novel ultrasensitive detection techniques and protein misfolding amplification assays hold the potential to optimize and accelerate this process.. Here we perform a PubMed-based state of the art review and perspective report on blood-based ultrasensitive detection techniques and protein misfolding amplification assays for biomarkers discovery and development in NDDs.. Ultrasensitive assays represent innovative solutions for blood-based assessments during the entire Alzheimer's disease (AD) biological and clinical continuum, for contexts of use (COU) such as prediction, detection, early diagnosis, and prognosis of AD. Moreover, cerebrospinal fluid (CSF)-based misfolding amplification assays show encouraging performance in detecting α-synucleinopathies in prodromal or at-high-risk individuals and may serve as tools for patients' stratification by the presence of α-synuclein pathology. Further clinical research will help overcome current methodological limitations, also through exploring multiple accessible bodily matrices. Eventually, integrative longitudinal studies will support precise definitions for appropriate COU across NDDs.

Topics: alpha-Synuclein; Alzheimer Disease; Biomarkers; Early Diagnosis; Humans; Neurodegenerative Diseases

Spreading of aggregate pathology across brain regions acts as a driver of disease progression in Tau-related neurodegeneration, including Alzheimer's disease (AD) and frontotemporal dementia. Aggregate seeds released from affected cells are internalized by naïve cells and induce the prion-like templating of soluble Tau into neurotoxic aggregates. Here we show in a cellular model system and in neurons that Clusterin, an abundant extracellular chaperone, strongly enhances Tau aggregate seeding. Upon interaction with Tau aggregates, Clusterin stabilizes highly potent, soluble seed species. Tau/Clusterin complexes enter recipient cells via endocytosis and compromise the endolysosomal compartment, allowing transfer to the cytosol where they propagate aggregation of endogenous Tau. Thus, upregulation of Clusterin, as observed in AD patients, may enhance Tau seeding and possibly accelerate the spreading of Tau pathology.

Topics: alpha-Synuclein; Animals; Clusterin; Disease Progression; Endocytosis; Humans; Mice; Neurodegenerative Diseases; Neurons; Protein Aggregation, Pathological; Protein Binding; tau Proteins

Growing evidence indicates that gut microbiota play a critical role in regulating the progression of neurodegenerative diseases such as Parkinson's disease. The molecular mechanism underlying such microbe-host interaction is unclear. In this study, by feeding

Topics: alpha-Synuclein; Amyloid; Animals; Biofilms; Caenorhabditis elegans; Escherichia coli; Escherichia coli Proteins; Genome-Wide Association Study; Genome, Bacterial; Host Microbial Interactions; Humans; Neurodegenerative Diseases

Aggregation of amyloidogenic proteins is an abnormal biological process implicated in neurodegenerative disorders. Whereas the aggregation process of amyloid-forming proteins has been studied extensively, the mechanism of aggregate removal is poorly understood. We recently demonstrated that proteasomes could fragment filamentous aggregates into smaller entities, restricting aggregate size [1]. Here, we show in vitro that UBE2W can modify the N-terminus of both α-synuclein and a tau tetra-repeat domain with a single ubiquitin. We demonstrate that an engineered N-terminal ubiquitin modification changes the aggregation process of both proteins, resulting in the formation of structurally distinct aggregates. Single-molecule approaches further reveal that the proteasome can target soluble oligomers assembled from ubiquitin-modified proteins independently of its peptidase activity, consistent with our recently reported fibril-fragmenting activity. Based on these results, we propose that proteasomes are able to target oligomers assembled from N-terminally ubiquitinated proteins. Our data suggest a possible disassembly mechanism by which N-terminal ubiquitination and the proteasome may together impede aggregate formation.

Topics: alpha-Synuclein; Amyloidogenic Proteins; Cytoplasm; Holoenzymes; Humans; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Protein Aggregation, Pathological; Protein Domains; Protein Multimerization; tau Proteins; Ubiquitin; Ubiquitin-Conjugating Enzymes; Ubiquitination

Neurodegenerative diseases are an enormous public health problem, affecting tens of millions of people worldwide. Nearly all of these diseases are characterized by oligomerization and fibrillization of neuronal proteins, and there is great interest in therapeutic targeting of these aggregates. Here, we show that soluble aggregates of α-synuclein and tau bind to plate-immobilized PrP in vitro and on mouse cortical neurons, and that this binding requires at least one of the same N-terminal sites at which soluble Aβ aggregates bind. Moreover, soluble aggregates of tau, α-synuclein and Aβ cause both functional (impairment of LTP) and structural (neuritic dystrophy) compromise and these deficits are absent when PrP is ablated, knocked-down, or when neurons are pre-treated with anti-PrP blocking antibodies. Using an all-human experimental paradigm involving: (1) isogenic iPSC-derived neurons expressing or lacking PRNP, and (2) aqueous extracts from brains of individuals who died with Alzheimer's disease, dementia with Lewy bodies, and Pick's disease, we demonstrate that Aβ, α-synuclein and tau are toxic to neurons in a manner that requires PrP

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Humans; Mice; Neurodegenerative Diseases; Neurons; Prions; Protein Binding; tau Proteins

Aggregations of β-amyloid (Aβ) and α-synuclein (αS) into oligomeric and fibrillar assemblies are the pathological hallmarks of Alzheimer's and Parkinson's diseases, respectively. Although Aβ and αS affect different regions of the brain and are separated at the cellular level, there is evidence of their eventual interaction in the pathology of both disorders. Characterization of interactions of Aβ and αS at various stages of their aggregation pathways could reveal mechanisms and therapeutic targets for the prevention and cure of these neurodegenerative diseases. In this study, we comprehensively examined the interactions and their molecular manifestations using an array of characterization tools. We show for the first time that αS monomers and oligomers, but not αS fibrils, inhibit Aβ fibrillization while promoting oligomerization of Aβ monomers and stabilizing preformed Aβ oligomers via coassembly, as judged by Thioflavin T fluorescence, transmission electron microscopy, and SDS- and native-PAGE with fluorescently labeled peptides/proteins. In contrast, soluble Aβ species, such as monomers and oligomers, aggregate into fibrils, when incubated alone under the otherwise same condition. Our study provides evidence that the interactions with αS soluble species, responsible for the effects, are mediated primarily by the C-terminus of Aβ, when judged by competitive immunoassays using antibodies recognizing various fragments of Aβ. We also show that the C-terminus of Aβ is a primary site for its interaction with αS fibrils. Collectively, these data demonstrate aggregation state-specific interactions between αS and Aβ and offer insight into a molecular basis of synergistic biological effects between the two polypeptides.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Benzothiazoles; Brain; Electrophoresis, Polyacrylamide Gel; Humans; Microscopy, Atomic Force; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Parkinson Disease; Peptide Fragments; Protein Aggregation, Pathological

Due to fast aggregation processes of many disordered proteins in neurodegenerative diseases, it is difficult to study their epitope regions at the monomeric and oligomeric levels. Computer simulations complement experiments and have been used to identify the epitope regions of proteins. Residues that adopt β-sheet conformation play a central role in the oligomerization and aggregation mechanisms of such proteins, including α-synuclein, which is at the center of Parkinson's and Alzheimer's diseases. In this study, we simulated the monomeric α-synuclein protein in an aqueous environment to evaluate its secondary structure properties, including β-sheet propensity, and radius of gyration by replica exchange molecular dynamics simulations. We also obtained the molecular dynamics simulation trajectories of α-synuclein that were conducted using various force field parameters by the David E. Shaw group. Using these trajectories, we calculated the impacts of force field parameters on α-synuclein secondary structure properties and radius of gyration values and obtained results are compared with our data from REMD simulations. This study shows that the chosen force field parameters and computer simulation techniques effect the predicted secondary structure properties and radius of gyration values of α-synuclein in water. Herewith, we illustrate the challenges in epitope region identification of intrinsically disordered proteins in neurodegenerative diseases by current computer simulations.

Topics: alpha-Synuclein; Binding Sites; Epitopes; Humans; Intrinsically Disordered Proteins; Molecular Dynamics Simulation; Neurodegenerative Diseases; Protein Aggregates; Protein Binding; Protein Conformation; Protein Structure, Secondary; Water

Parkinson's disease (PD) is characterized by the accumulation of misfolded and aggregated α-synuclein (α-syn) into intraneuronal inclusions named Lewy bodies (LBs). Although it is widely believed that α-syn plays a central role in the pathogenesis of PD, the processes that govern α-syn fibrillization and LB formation remain poorly understood. In this work, we sought to dissect the spatiotemporal events involved in the biogenesis of the LBs at the genetic, molecular, biochemical, structural, and cellular levels. Toward this goal, we further developed a seeding-based model of α-syn fibrillization to generate a neuronal model that reproduces the key events leading to LB formation, including seeding, fibrillization, and the formation of inclusions that recapitulate many of the biochemical, structural, and organizational features of bona fide LBs. Using an integrative omics, biochemical and imaging approach, we dissected the molecular events associated with the different stages of LB formation and their contribution to neuronal dysfunction and degeneration. In addition, we demonstrate that LB formation involves a complex interplay between α-syn fibrillization, posttranslational modifications, and interactions between α-syn aggregates and membranous organelles, including mitochondria, the autophagosome, and endolysosome. Finally, we show that the process of LB formation, rather than simply fibril formation, is one of the major drivers of neurodegeneration through disruption of cellular functions and inducing mitochondria damage and deficits, and synaptic dysfunctions. We believe that this model represents a powerful platform to further investigate the mechanisms of LB formation and clearance and to screen and evaluate therapeutics targeting α-syn aggregation and LB formation.

Topics: alpha-Synuclein; Animals; Autophagosomes; Humans; Lewy Bodies; Lysosomes; Mitochondria; Neurodegenerative Diseases; Neurons; Parkinson Disease; Transcriptome

Topics: 1-Methyl-4-phenylpyridinium; Active Transport, Cell Nucleus; alpha-Synuclein; Animals; Autophagy; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Cell Line, Tumor; Cell Survival; Curcumin; HeLa Cells; Humans; Lysosomes; Neurodegenerative Diseases; Neurons; Parkinson Disease; PC12 Cells; Rats; RNA Interference; Signal Transduction

Human neurodegenerative diseases can be characterized as disorders of protein aggregation. As a key player in cellular autophagy and the ubiquitin proteasome system, p62 may represent an effective immunohistochemical target, as well as mechanistic operator, across neurodegenerative proteinopathies. In this study, 2 novel mouse-derived monoclonal antibodies 5G3 and 2A5 raised against residues 360-380 of human p62/sequestosome-1 were characterized via immunohistochemical application upon human tissues derived from cases of C9orf72-expansion spectrum diseases, Alzheimer disease, progressive supranuclear palsy, Lewy body disease, and multiple system atrophy. 5G3 and 2A5 reliably highlighted neuronal dipeptide repeat, tau, and α-synuclein inclusions in a distribution similar to a polyclonal antibody to p62, phospho-tau antibodies 7F2 and AT8, and phospho-α-synuclein antibody 81A. However, antibodies 5G3 and 2A5 consistently stained less neuropil structures, such as tau neuropil threads and Lewy neurites, while 2A5 marked fewer glial inclusions in progressive supranuclear palsy. Both 5G3 and 2A5 revealed incidental astrocytic tau immunoreactivity in cases of Alzheimer disease and Lewy body disease with resolution superior to 7F2. Through their unique ability to highlight specific types of pathological deposits in neurodegenerative brain tissue, these novel monoclonal p62 antibodies may provide utility in both research and diagnostic efforts.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Antibodies, Monoclonal; Astrocytes; Cells, Cultured; Female; Humans; Immunohistochemistry; Inclusion Bodies; Male; Mice, Inbred BALB C; Middle Aged; Neurodegenerative Diseases; Sequestosome-1 Protein; tau Proteins

Microglia maintain brain homeostasis by removing neuron-derived components such as myelin and cell debris. The evidence linking microglia to neurodegenerative diseases is growing; however, the precise mechanisms remain poorly understood. Herein, we report a neuroprotective role for microglia in the clearance of neuron-released α-synuclein. Neuronal α-synuclein activates microglia, which in turn engulf α-synuclein into autophagosomes for degradation via selective autophagy (termed synucleinphagy). Synucleinphagy requires the presence of microglial Toll-like receptor 4 (TLR4), which induces transcriptional upregulation of p62/SQSTM1 through the NF-κB signaling pathway. Induction of p62, an autophagy receptor, is necessary for the formation of α-synuclein/ubiquitin-positive puncta that are degraded by autophagy. Finally, disruption of microglial autophagy in mice expressing human α-synuclein promotes the accumulation of misfolded α-synuclein and causes midbrain dopaminergic neuron degeneration. Our study thus identifies a neuroprotective function of microglia in the clearance of α-synuclein via TLR4-NF-κB-p62 mediated synucleinphagy.

Topics: alpha-Synuclein; Animals; Autoantigens; Autophagy; Brain; Disease Models, Animal; Dopaminergic Neurons; Female; HEK293 Cells; Humans; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Neurodegenerative Diseases; NF-kappa B; Signal Transduction; Toll-Like Receptor 4

Parkinson's disease (PD) is a progressive neurodegenerative disease which is histologically characterized by loss of dopaminergic neurons in the substantia nigra and deposition of aggregated alpha-synuclein (aSyn) in the brain. The detection of aSyn in well accessible fluids has been one of the central approaches in the development of biomarkers for PD. Recently, real-time quaking-induced conversion (RT-QuIC) has been successfully adapted for use with aSyn seeds. Here, we systematically analysed parameters potentially impacting the reliability of this assay by using quantitative real-time quaking-induced conversion (qRT-QuIC) with in vitro-formed aSyn seeds. Seeds diluted in cerebrospinal fluid (CSF) accelerated the seeding reaction and slightly increased the sensitivity without affecting specificity. Repeated freeze-thaw cycles decreased the apparent lag times of seeds diluted in ddH

Topics: Aged; alpha-Synuclein; Artifacts; Biological Assay; Biomarkers; Brain; Female; Humans; Male; Middle Aged; Neurodegenerative Diseases; Parkinson Disease; Reproducibility of Results; Sensitivity and Specificity

Metformin, a widely prescribed antidiabetic drug, has been suggested to have a neuroprotective effect on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in mice. In this study, we investigated the neuroprotective potential of metformin against rotenone-induced dopaminergic neuron damage and its underlying mechanisms.. C57BL/6 mice were given saline or rotenone (2.5 mg/kg/day, ip) injection for 10 days. Metformin treatment (300 mg/kg/day, ip) was started concurrently with rotenone administration and continued for 10 days. The neuroprotective effect of metformin on rotenone-induced dopaminergic toxicity was assessed by tyrosine hydroxylase (TH), cleaved caspase-3 and α-synuclein immunohistochemistry in substantia nigra (SN). SN tissues were extracted for biochemical analysis. Malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) protein levels were measured by spectrophotometric assay.. We found that metformin treatment attenuated the rotenone-induced loss of TH. Results showed that metformin treatment attenuated dopaminergic neuron loss in SN induced by rotenone by decreasing lipid peroxidation.

Topics: alpha-Synuclein; Animals; Dopamine; Dopaminergic Neurons; Lipid Peroxidation; Male; Metformin; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Neuroprotective Agents; Rotenone; Substantia Nigra; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is the second most common neurodegenerative disorder, but the disease-modifying therapies focusing on the core pathological changes are still unavailable. Rho-associated protein kinase (ROCK) has been suggested as a promising target for developing neuroprotective therapies in PD.. We aimed to explore the promotion of α-synuclein (α-syn) clearance in a rat model.. In a rat model induced by unilateral injection of adeno-associated virus of serotype 9 (AAV9) expressing A53T α-syn (AAV9-A53T-α-syn) into the right substantia nigra, we aimed to investigate whether Fasudil could promote α-syn clearance and thereby attenuate motor impairments and dopaminergic deficits.. In our study, treatment with Fasudil (5 mg/kg rat weight/day) for 8 weeks significantly improved the motor deficits in the Cylinder and Rotarod tests. In the in vivo positron emission tomography imaging with the ligand 18F-dihydrotetrabenazine, Fasudil significantly enhanced the dopaminergic imaging in the injected striatum of the rat model (p < 0.05 vs. vehicle group, p < 0.01 vs. left striatum in Fasudil group). The following mechanistic study confirmed that Fasudil could promote the autophagic clearance of α-syn by Becline 1 and Akt/mTOR pathways.. Our study suggested that Fasudil, the ROCK2 inhibitor, could attenuate the anatomical and behavioral lesions in the Parkinsonian rat model by autophagy activation. Our results identify Fasudil as a drug with high translational potential as disease-modifying treatment for PD and other synucleinopathies.

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Neurodegenerative Diseases; Parkinson Disease; Rats, Sprague-Dawley; Substantia Nigra

Amyloid self-assembly is pathologically linked to many neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). While many inhibitors have been developed individually for specific amyloid proteins, there are a few effective platforms to screen on a large scale general amyloid inhibitors against different amyloid proteins. Herein, we developed a new class of amyloid inhibitor probes by site-specific conjugation of aggregation-induced emission (AIE) molecules with amyloid proteins (i.e., AIE@amyloid probes) to realize a high-throughput screening of small-molecule inhibitors. Optimization of site-specific AIE conjugation with two amyloid proteins, amyloid-β protein (Aβ) and α-synuclein (αSN), enabled us to retain their high amyloidogenic properties; i.e., AIE-amyloid probes alone exhibited strong fluorescence due to amyloid-like aggregation, but they showed no fluorescence in the presence of amyloid inhibitors to prevent amyloid aggregation. From integration of AIE@amyloid probes and computational virtual screening from a large drug database, it was found that tolcapone possessed a dual inhibition against the aggregation and cytotoxicity of both Aβ and αSN. More importantly, tolcapone significantly improved the spatial cognition and recognition of Aβ-treated mice. This work represents an innovative attempt to design an AIE-based anti-amyloid drug platform for identifying new small-molecule inhibitors against amyloidogenesis in both AD and PD or other amyloid diseases.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Amyloid beta-Peptides; Amyloidogenic Proteins; Animals; Mice; Molecular Dynamics Simulation; Neurodegenerative Diseases; Parkinson Disease; Tolcapone

The role of Discoidin Domain Receptors (DDRs) is poorly understood in neurodegeneration. DDRs are upregulated in Alzheimer's and Parkinson's disease (PD), and DDRs knockdown reduces neurotoxic protein levels. Here we show that potent and preferential DDR1 inhibitors reduce neurotoxic protein levels in vitro and in vivo. Partial or complete deletion or inhibition of DDR1 in a mouse model challenged with α-synuclein increases autophagy and reduces inflammation and neurotoxic proteins. Significant changes of cerebrospinal fluid microRNAs that control inflammation, neuronal injury, autophagy and vesicular transport genes are observed in PD with and without dementia and Lewy body dementia, but these changes are attenuated or reversed after treatment with the DDR1 inhibitor, nilotinib. Collectively, these data demonstrate that DDR1 regulates autophagy and reduces neurotoxic proteins and inflammation and is a therapeutic target in neurodegeneration.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Discoidin Domain Receptor 1; Disease Models, Animal; Humans; Inflammation; Lewy Body Disease; Mice; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; Pyrimidines

Toxic abnormal aggregation of α-synuclein (α-Syn) is a feature of Parkinson's disease. Several biochemical and biophysical studies have demonstrated that many post-translational modifications (PTM) of α-Syn could distinctly alleviate its oligomerization-mediated toxicity. Recently, a compelling link is emerging between the PTM O-GlcNAcylation (O-GlcNAc) and protein aggregation, yet the underlying molecular mechanism remains unclear. Based on the all-atom molecular dynamics simulations, we found that O-GlcNAc modifications can suppress the process of oligomerization of α-Syn aggregates via a steric effect-the additional O-linked glycosyl group disrupts the formation of hydrogen bonds (H-bonds) between α-Syn monomers. Besides, we proposed a theoretical model to further capture the physical mechanism of α-Syn aggregation/disaggregation in the absence/presence of O-GlcNAc-modified α-Syn. Our findings unveil the molecular mechanism of the O-GlcNAc-induced inhibition of α-Syn oligomerization, which may help to understand how O-GlcNAc prevents the oligomerization of other proteins and provides the guideline for the development of O-GlcNAc-based therapeutic strategies in neurodegenerative diseases.

Topics: Acylation; alpha-Synuclein; Models, Biological; Neurodegenerative Diseases; Polymerization; Protein Aggregation, Pathological; Protein Processing, Post-Translational

Exposure to fenpropathrin (Fen), one of the most widely used pyrethroid pesticides, has been reported to increase the incidence of Parkinson's disease (PD). However, the molecular mechanisms underlying Fen-induced Parkinsonism remain unknown. Here we investigated the role of the lysosomal protease asparagine endopeptidase (AEP) in Fen-induced neurodegeneration and tested the protective effect of an AEP inhibitor Compound #11 (CP11). Fen induced AEP activation, α-synuclein aggregation, and dopaminergic neuronal degeneration both in vitro and in vivo. CP11 alleviated Fen-induced cell injury in cultured SH-SY5Y cells and A53T α-synuclein transgenic mice. CP11 protected SH-SY5Y cells against Fen-induced toxicity and decreased α-synuclein aggregation in HEK293 cells stably transfected with α-synuclein. In Fen-treated mice, CP11 attenuated the degeneration of dopaminergic neurons and reduced neuroinflammation. Our findings demonstrate that neurodegeneration in Fen-treated models might be attributed to the activation of AEP. AEP might be a novel therapeutic target in PD induced by Fen and other environmental factors.

Topics: alpha-Synuclein; Animals; Cell Line, Tumor; Cysteine Endopeptidases; Dose-Response Relationship, Drug; Female; HEK293 Cells; Humans; Male; Mice; Mice, Transgenic; Neurodegenerative Diseases; Neuroprotective Agents; Protease Inhibitors; Protein Aggregates; Pyrethrins

Misfolded oligomeric α-synuclein plays a pivotal role in the pathogenesis of α-synucleinopathies including Parkinson's disease and multiple system atrophy, and its detection parallels activation of microglia and a loss of neurons in the substantia nigra pars compacta. Here we aimed to analyze the therapeutic efficacy of PD03, a new AFFITOPE® immunotherapy approach, either alone or in combination with Anle138b, in a PLP-α-syn mouse model.. The PLP-α-syn mice were treated with PD03 immunotherapy, Anle138b, or a combination of two. Five months after study initiation, the mice underwent behavioral testing and were sacrificed for neuropathological analysis. The treatment groups were compared to the vehicle group with regard to motor performance, nigral neuronal loss, microglial activation and α-synuclein pathology.. The PLP-α-syn mice receiving the PD03 or Anle138b single therapy showed improvement of gait deficits and preservation of nigral dopaminergic neurons associated with the reduced α-synuclein oligomer levels and decreased microglial activation. The combined therapy with Anle138b and PD03 resulted in lower IgG binding in the brain as compared to the single immunotherapy with PD03.. PD03 and Anle138b can selectively target oligomeric α-synuclein, resulting in attenuation of neurodegeneration in the PLP-α-syn mice. Both approaches are potential therapies that should be developed further for disease modification in α-synucleinopathies.

Topics: alpha-Synuclein; Animals; Benzodioxoles; Drug Delivery Systems; Female; Immunologic Factors; Male; Mice; Mice, Transgenic; Multiple System Atrophy; Neurodegenerative Diseases; Pyrazoles

Parkinson's disease (PD) is one of the common complex neurodegenerative diseases and characterized by abnormal metabolic brain networks. Fibroblast growth factor 21 (FGF21), an endocrine hormone that belongs to the fibroblast growth factor superfamily, plays an extensive role in the regulation of metabolism. However, our understandings of the specific function and mechanisms of FGF21 on PD are still quite limited. Here we aimed to elucidate the actions and the underlying mechanisms of FGF21 on dopaminergic neurodegeneration using cellular and animal models of parkinsonism. To investigate the effects of FGF21 on dopaminergic neurodegeneration in vivo and in vitro, 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine models of PD were utilized, and animals were treated with recombinant FGF21 protein or FGF21 gene delivered via an adeno-associated virus. In the present study, systemic and continuous intracerebroventricular recombinant FGF21 protein administration to mice both prevented behavioral deficits, protected dopaminergic neurons against degeneration, and ameliorated α-synuclein pathology in PD models; and in vivo gene delivery of FGF21 improved PD-like symptoms and pathologies suggesting a potential implication of FGF21 in gene therapy for PD. In vitro evidence confirmed FGF21 mediated neuroprotective benefits against PD pathologies. Further, our data suggested that enhanced autophagy was involved in the FGF21 neuroprotection in PD models, and silent information regulator 2 homolog 1 may play a crucial role in molecular mechanisms underlying anti-PD activities of FGF21.

Topics: alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Dopaminergic Neurons; Fibroblast Growth Factors; Genetic Therapy; Humans; Male; Mice; Mice, Inbred C57BL; MPTP Poisoning; Neurodegenerative Diseases; Neuroprotection; Parkinson Disease, Secondary; Recombinant Proteins; Sirtuin 1

The underlying mechanism of viral infection as a risk factor for Parkinson's disease (PD), the second most common neurodegenerative disease, remains unclear.. We used Mac-1. Dopaminergic neurons in the nigra and striatum were markedly reduced in WT mice after administration of poly I:C together with abundant microglial activation in the SN, and the expression of α-synuclein was also elevated. However, these pathological changes were greatly dampened in Mac-1. Our findings demonstrated that viral infection could result in the activation of microglia as well as NADPH oxidase, which may lead to neuron loss and the development of Parkinson's-like symptoms. Mac-1 is a key receptor during this process.

Topics: alpha-Synuclein; Animals; Cell Death; Corpus Striatum; Dopaminergic Neurons; Inflammation; Macrophage-1 Antigen; Male; Mice; Mice, Knockout; Microglia; NADPH Oxidase 2; NADPH Oxidases; Neurodegenerative Diseases; RNA, Double-Stranded; Substantia Nigra

Parkinson's disease (PD) is the second most common neurodegenerative disease affecting millions of elder people due to the degeneration of dopamine neurons in the striatum and substantia nigra. The clinical manifestations of PD include tremor, rigidity, bradykinesia and postural instability. Studying PD is challenging due to two obstacles: 1) disease models such as primary neurons or animal models usually couldn't recapitulate the disease phenotype, and 2) accessibility of human autopsied brain samples is very limited if not impossible. Induced pluripotent stem cells (iPSCs)-derived neuronal cells from patients emerge as an ideal in vitro model for disease modeling and drug development. Here we describe a cell density-dependent method for preparing functional hiPSC-derived dopamine neurons (iDAs) with ~90% purity (TH-positive cells). iDAs derived from PD patient exhibit the disease-related phenotypes, for example, slowed morphogenesis, reduced dopamine release, impaired mitochondrial function, and α-synuclein accumulation as early as 35 days after induction. Furthermore, we found that the effects of cell density are different between iDA development stages, whereas high cell density increases stress for early neural progenitor cells (NPCs), but are neural-protective for mature iDAs, high density also favors morphogenesis. Hence, using stage and density-dependent strategies we can obtain high quality iDAs, which are critical for disease modeling, drug development and cell replacement therapy.

Topics: Aged; alpha-Synuclein; Animals; Dopaminergic Neurons; Humans; Induced Pluripotent Stem Cells; Neurodegenerative Diseases; Parkinson Disease

Studies on the amyloidogenic N-terminal domain of the E. coli HypF protein (HypF-N) have contributed significantly to a detailed understanding of the pathogenic mechanisms in neurodegenerative diseases characterised by the formation of misfolded oligomers, by proteins such as amyloid-β, α-synuclein and tau. Given that both cell membranes and mitochondria are increasingly recognised as key targets of oligomer toxicity, we investigated the damaging effects of aggregates of HypF-N on mitochondrial membranes. Essentially, we found that HypF-N oligomers characterised by high surface hydrophobicity (type A) were able to trigger a robust permeabilisation of mito-mimetic liposomes possessing cardiolipin-rich membranes and dysfunction of isolated mitochondria, as demonstrated by a combination of mitochondrial shrinking, lowering of mitochondrial membrane potential and cytochrome c release. Furthermore, using single-channel electrophysiology recordings we obtained evidence that the type A aggregates induced currents reflecting formation of ion-conducting pores in mito-mimetic planar phospholipid bilayers, with multi-level conductances ranging in the hundreds of pS at negative membrane voltages. Conversely, HypF-N oligomers with low surface hydrophobicity (type B) could not permeabilise or porate mitochondrial membranes. These results suggest an inherent toxicity of membrane-active aggregates of amyloid-forming proteins to mitochondria, and that targeting of oligomer-mitochondrial membrane interactions might therefore afford protection against such damage.

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Carboxyl and Carbamoyl Transferases; Cardiolipins; Escherichia coli; Escherichia coli Proteins; Humans; Hydrophobic and Hydrophilic Interactions; Lipid Bilayers; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Membranes; Neurodegenerative Diseases; Protein Conformation; Protein Multimerization; Structure-Activity Relationship; tau Proteins

Amyloid formation drives the pathology of different neurodegenerative diseases. α-Synuclein is a natively unfolded protein that assembles itself into toxic amyloid structures, hence contributing to synucleinopathy. Its amyloid formation proceeds through various conformational intermediate stages, starting with a lag phase, followed by a rapid growth phase, and leading to beta rich fibril formation. Few studies have shown that the helix rich intermediate may be involved in fibril formation. Earlier, the helix intermediate was only studied in the membrane bound state. Despite many years of research, a precise mechanism of α-synuclein aggregation and the significance of intermediates with variable secondary structures are not well elucidated. Therefore, this study aims to understand the importance of secondary structures in α-synuclein-mediated neuronal toxicity. Our data revealed that the helix rich intermediate species exposes more of the hydrophobic surface than the beta rich intermediate species and harbors with the lipid membrane efficiently, thus contributing to the greater roughness of the cellular membrane that subsequently results in membrane disruption. It has been seen that upon internalization these species also activate the redox machinery. β-Sheet enrichment contributes to self-assemblies of monomeric α-synuclein as it binds more with the monomeric species than the helix rich species. Additionally, we also observed that the beta rich species exhibits stronger TLR2 binding than the helix rich species as well as a potentiated neuroinflammatory cascade. Taken together, our data evidently put forward that secondary structures play a differential role during amyloid formation, and targeting them can be a novel intervention strategy for neurodegenerative disease progression.

Topics: alpha-Synuclein; Amyloid; Humans; Neurodegenerative Diseases; Protein Structure, Secondary; Toll-Like Receptor 2

Accumulating reports have suggested that α-synuclein is involved in the pathogenesis of Alzheimer's disease (AD). As the cerebrospinal fluid (CSF) α-synuclein has been suggested as a potential biomarker of AD, this study was set out to test whether CSF α-synuclein is associated with other AD biomarkers and could predict neurodegeneration and clinical progression in non-demented elders.. The associations between CSF α-synuclein and other AD biomarkers were investigated at baseline in non-demented Chinese elders. The predictive values of CSF α-synuclein for longitudinal neuroimaging change and the conversion risk of non-demented elders were assessed using linear mixed effects models and multivariate Cox proportional hazard models, respectively, in the Alzheimer's disease Neuroimaging Initiative (ADNI) database.. The CSF α-synuclein levels correlated with AD-specific biomarkers, CSF total tau and phosphorylated tau levels, in 651 Chinese Han participants (training set). These positive correlations were replicated in the ADNI database (validation set). Using a longitudinal cohort from ADNI, the CSF α-synuclein concentrations were found to increase with disease severity. The CSF α-synuclein had high diagnostic accuracy for AD based on the "ATN" (amyloid, tau, neurodegeneration) system (A + T+ versus A - T - control) (area under the receiver operating characteristic curve, 0.84). Moreover, CSF α-synuclein predicted longitudinal hippocampus atrophy and conversion from MCI to AD dementia.. CSF α-synuclein is associated with CSF tau levels and could predict neurodegeneration and clinical progression in non-demented elders. This finding indicates that CSF α-synuclein is a potentially useful early biomarker for AD.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Biomarkers; China; Cohort Studies; Dementia; Disease Progression; Female; Humans; Male; Middle Aged; Neurodegenerative Diseases; Predictive Value of Tests

Topics: alpha-Synuclein; Animals; Atrial Natriuretic Factor; Exosomes; Mice; Neurodegenerative Diseases; Parkinson Disease

The AAA+ protein disaggregase, Hsp104, increases fitness under stress by reversing stress-induced protein aggregation. Natural Hsp104 variants might exist with enhanced, selective activity against neurodegenerative disease substrates. However, natural Hsp104 variation remains largely unexplored. Here, we screened a cross-kingdom collection of Hsp104 homologs in yeast proteotoxicity models. Prokaryotic ClpG reduced TDP-43, FUS, and α-synuclein toxicity, whereas prokaryotic ClpB and hyperactive variants were ineffective. We uncovered therapeutic genetic variation among eukaryotic Hsp104 homologs that specifically antagonized TDP-43 condensation and toxicity in yeast and TDP-43 aggregation in human cells. We also uncovered distinct eukaryotic Hsp104 homologs that selectively antagonized α-synuclein condensation and toxicity in yeast and dopaminergic neurodegeneration in

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Cell Line; DNA-Binding Proteins; Endopeptidase Clp; Escherichia coli; Genetic Variation; Heat-Shock Proteins; HEK293 Cells; Humans; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Folding; Proteostasis Deficiencies; RNA-Binding Protein FUS; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins

Functional foods enriched with plant polyphenols and anthocyanins in particular attract special attention due to multiple beneficial bioactive properties of the latter. We evaluated the effects of a grain diet rich in anthocyanins in a mouse model of Alzheimer's disease induced by amyloid-beta (Aβ) and a transgenic mouse model of Parkinson's disease (PD) with overexpression of human alpha-synuclein. The mice were kept at a diet that consisted of the wheat grain of near isogenic lines differing in anthocyanin content for five-six months. The anthocyanin-rich diet was safe and possessed positive effects on cognitive function. Anthocyanins prevented deficits in working memory induced by Aβ or a long-term grain mono-diet; they partially reversed episodic memory alterations. Both types of grain diets prolonged memory extinction and rescued its facilitation in the PD model. The dynamics of the extinction in the group fed with the anthocyanin-rich wheat was closer to that in a group of wild-type mice given standard chow. The anthocyanin-rich diet reduced alpha-synuclein accumulation and modulated microglial response in the brain of the transgenic mice including the elevated expression of arginase1 that marks M2 microglia. Thus, anthocyanin-rich wheat is suggested as a promising source of functional nutrition at the early stages of neurodegenerative disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Analysis of Variance; Animals; Anthocyanins; Arginase; Avoidance Learning; Disease Models, Animal; Food, Fortified; Functional Food; Male; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Neurodegenerative Diseases; Open Field Test; Parkinson Disease; Triticum; Weight Gain

Parkinson's disease is a neurodegenerative movement disorder; however, peripheral symptoms can arise decades prior. In this issue of Neuron, Kim et al. (2019) provide evidence that progressive α-synuclein aggregation initiating in the gut could be a pathogenic epicenter anatomically rippling throughout the nervous system.

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

The most common neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, are known to be protein-misfolding diseases, and characterized by the presence of disease-specific protein aggregates in neuronal and glial cells. Recently, the propagation hypothesis of prion-like protein inclusions in neurodegenerative diseases has been proposed. Many studies have shown that aggregation-prone proteins such as tau, alpha-synuclein and TDP-43 can form aggregates in a seed-dependent and self-templating prion-like manner, and these aggregates can be transferred intercellularly to neighboring cells and seeded for further aggregation. Propagation of aggregated proteins in these diseases may therefore occur through mechanisms similar to those that underlie prion pathogenesis. If this hypothesis is verified in vivo, it will suggest new therapeutic strategies to block the propagation of aggregated proteins throughout the brain.

Topics: alpha-Synuclein; Alzheimer Disease; Amyotrophic Lateral Sclerosis; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Parkinson Disease; Prion Diseases; Prions; tau Proteins

Plethora of efforts fails to yield a single drug to reverse the pathogenesis of Parkinson's disease (PD) and related α-synucleopathies.. Using chemical biology, we identified a small molecule inhibitor of c-abl kinase, PD180970 that could potentially clear the toxic protein aggregates. Genetic, molecular, cell biological and immunological assays were performed to understand the mechanism of action. In vivo preclinical disease model of PD was used to assess its neuroprotection efficacy.. In this report, we show the ability of a small molecule inhibitor of tyrosine kinases, PD180970, to induce autophagy (cell lines and mice midbrain) in an mTOR-independent manner and ameliorate the α-synuclein mediated toxicity. PD180970 also exerts anti-neuroinflammatory potential by inhibiting the release of proinflammatory cytokines such as IL-6 (interleukin-6) and MCP-1 (monocyte chemoattractant protein-1) through reduction of TLR-4 (toll like receptor-4) mediated NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation. In vivo studies show that PD180970 is neuroprotective by degrading the toxic protein oligomers through induction of autophagy and subsiding the microglial activation.. These protective mechanisms ensure the negation of Parkinson's disease related motor impairments. FUND: This work was supported by Wellcome Trust/DBT India Alliance Intermediate Fellowship (500159-Z-09-Z), DST-SERB grant (EMR/2015/001946), DBT (BT/INF/22/SP27679/2018) and JNCASR intramural funds to RM, and SERB, DST (SR/SO/HS/0121/2012) to PAA, and DST-SERB (SB/YS/LS-215/2013) to JPC and BIRAC funding to ETA C-CAMP.

Topics: alpha-Synuclein; Animals; Biomarkers; Cell Line; Cytokines; Disease Models, Animal; Humans; Immunohistochemistry; Interleukin-6; Lipopolysaccharides; Macroautophagy; Male; Mice; Microglia; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Oxidative Stress; Protein Aggregates; Protein Aggregation, Pathological; Pyridones; Pyrimidines

It is becoming increasingly clear that brain network organization shapes the course and expression of neurodegenerative diseases. Parkinson disease (PD) is marked by progressive spread of atrophy from the midbrain to subcortical structures and, eventually, to the cerebral cortex. Recent discoveries suggest that the neurodegenerative process involves the misfolding and prion-like propagation of endogenous α-synuclein via axonal projections. However, the mechanisms that translate local "synucleinopathy" to large-scale network dysfunction and atrophy remain unknown. Here, we use an agent-based epidemic spreading model to integrate structural connectivity, functional connectivity, and gene expression and to predict sequential volume loss due to neurodegeneration. The dynamic model replicates the spatial and temporal patterning of empirical atrophy in PD and implicates the substantia nigra as the disease epicenter. We reveal a significant role for both connectome topology and geometry in shaping the distribution of atrophy. The model also demonstrates that SNCA and GBA transcription influence α-synuclein concentration and local regional vulnerability. Functional coactivation further amplifies the course set by connectome architecture and gene expression. Altogether, these results support the theory that the progression of PD is a multifactorial process that depends on both cell-to-cell spreading of misfolded proteins and regional vulnerability.

Topics: alpha-Synuclein; Atrophy; Brain; Connectome; Databases, Factual; Diffusion Magnetic Resonance Imaging; Humans; Models, Theoretical; Nerve Net; Neurodegenerative Diseases; Parkinson Disease; Transcriptome

Alpha-synuclein (α-syn) aggregation is a neuropathological hallmark of neurodegenerative synucleinopathies. This in vivo study explored glucose metabolism and dopaminergic and serotoninergic neurotransmission in KO α-syn, wild-type mice and an accelerated murine model of synucleinopathy (M83).. MicroPET acquisitions were performed in all animals aged 5-6 months using five radiotracers exploring brain glucose metabolism ([. MicroPET data showed a decrease in [. This PET study highlights an effect of α-syn modulation on the expression of the D

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Dopamine; Female; Male; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Positron-Emission Tomography; Radiopharmaceuticals; Serotonin; Synaptic Transmission

Alzheimer's disease (AD) is characterized by accumulation of β-amyloid plaques (AP) and neurofibrillary tangles (NFT) in the cortex, together with synaptic loss and amyloid angiopathy. Perturbations in the brain lysosomal system, including the cathepsin family of proteases, have been implicated in AD where they may be involved in proteolytic clearance of misfolded and abnormally aggregated peptides. However, the status of cathepsin D (catD) is unclear in Lewy body dementia, the second most common form of neurodegenerative dementia after AD, and characterized by Lewy bodies (LB) containing aggregated α-synuclein. Furthermore, earlier reports of catD changes in AD have not been entirely consistent. We measured CatD immunoreactivities in the temporal (Brodmann area BA21) and parietal (BA40) cortices of well characterized AD brains as well as two clinical subtypes of Lewy body dementia, namely Parkinson disease dementia (PDD) and dementia with Lewy bodies (DLB), known to show varying degrees of concomitant AD pathology. Increased catD immunoreactivities in AD were found for both neocortical regions measured, where they also correlated with neuropathological NFT scores and phosphorylated pSer396 tau burden, and appeared to co-localize at least partly to NFT-containing neurons. In contrast, catD was increased only in BA40 in DLB and not at all in PDD, did not correlate with LB scores, and did not appreciably co-localize with α-synuclein inclusions. Our study suggests that catD upregulation may be an adaptive response to AD-related processes leading to neurofibrillary degeneration, but may not be directly associated with formation of α-synuclein inclusions in Lewy body dementia.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Cathepsin D; Female; Humans; Lewy Bodies; Lewy Body Disease; Male; Neocortex; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Parietal Lobe; Plaque, Amyloid; tau Proteins; Temporal Lobe

Parkinson's disease (PD) is a serious neurodegenerative disease and is characterized by abnormal α-synuclein (α-syn) accumulation in Lewy bodies (LB) and Lewy neurites (LN), which makes α-syn an important imaging target for PD. An imaging probe that quantifies fibrillar α-syn can enhance the clinical diagnosis of PD and can also be used to evaluate the efficacy of therapeutics aimed at reducing the abnormal aggregation of the α-syn fibril in the brain. In this paper, we study the binding profile of fibrillar α-syn with a fluorescent probe 4-(dicyanovinyl)julolidine (DCVJ), which is being explored for identifying α-syn imaging agents. A multiscale simulation workflow including molecular docking, molecular dynamics, metadynamics, and QM/MM calculations was implemented. We find that DCVJ can bind to multiple sites of α-syn which are located either at the surface or in the core. Free energy calculations using implicit solvent models reveal that the most favorable binding mode for DCVJ is associated with the core binding site and is further confirmed by metadyamics simulation. Besides, a dynamic binding pathway is discovered, which reveals that DCVJ binds gradually into the core of the fibril passing through several intermediate states. The conformational arrest of the dicyano vinyl group in the fibrillar environment could explain the reason behind the fibril-specific fluorescence of DCVJ. Furthermore, based on hybrid QM/MM calculations, the molecular geometry of the dicyano vinyl group is found to be environment specific which explains why DCVJ serves as a staining agent for such fibrillar-like environments. Our results could be helpful for elucidating the binding mechanism of imaging tracers with the fibrillar form of α-syn and explain their fibrillar-specific optical properties, a knowledge that in turn can be used to guide the design and development of compounds with higher affinity and selectivity for α-syn using structure-based strategies.

Topics: alpha-Synuclein; Brain; Fluorescent Dyes; Humans; Lewy Bodies; Molecular Docking Simulation; Neurodegenerative Diseases; Parkinson Disease

Topics: alpha-Synuclein; DNA; DNA-Binding Proteins; Humans; Neurodegenerative Diseases

We recently identified a truncated and phosphorylated form of α-synuclein, pα-syn*, as a key neurotoxic α-synuclein species found in cultured neurons, as well as in mouse and Parkinson's disease patients' brains. Small pα-syn* aggregates localize to mitochondria and induce mitochondrial damage and fragmentation. Herein, we investigated the molecular basis of pα-syn*-induced toxicity. By immunofluorescence, we found phosphorylated MKK4, JNK, ERK5 and p38 MAPKs in pα-syn* inclusions. pJNK colocalized with pα-syn* at mitochondria and mitochondria-associated ER membranes where it was associated with BiP and pACC1, markers for the ER and energy deprivation, respectively. We also found that pα-syn* aggregates are tightly associated with small ptau aggregates of similar size. Pα-syn*/ptau inclusions localized to areas of mitochondrial damage and to mitophagic vesicles, showing their role in mitochondrial toxicity, mitophagy induction and their removal along with damaged mitochondrial fragments. Several MAPKs may act cooperatively to phosphorylate tau, notably JNK, p38 and GSK3β, a non-MAPK that was also found phosphorylated in the vicinity of pα-syn*/ptau aggregates. These results add insight into the mechanisms by which pα-syn* exerts its toxic effects that include the phosphorylation of several kinases of the MAPK pathway, as well as the formation of ptau at the mitochondrial membrane, likely contributing to mitotoxicity. Thus pα-syn* appears to be the trigger of a series of kinase mediated pathogenic events and a link between α-syn pathology and tau, another protein known to aggregate in Parkinson's disease and other synucleinopathies.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mitochondria; Neurodegenerative Diseases; Phosphorylation; tau Proteins

α-Synuclein was recently found to interact with moonlighting glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) involved in neurodegenerative diseases development. In the present work, we have analyzed influence of α-synuclein glycation on this interaction, because the literature data suggest relation between diabetes and Parkinson's disease. According to zeta potential measurement, glycation can shift the charge of α-synuclein to more negative values that was pronounced in case of modification by glyceraldehyde-3-phosphate. We selected carboxymethyl lysine as a typical advanced glycation end product and performed molecular dynamics simulations. The binding was found to be electrostatically driven and was significantly amplified after α-synuclein glycation because of increase the number of acidic residues. Since the main binding site was located in the anion-binding groove, which comprises the active site of GAPDH, enhanced binding of α-synuclein can result in GAPDH inactivation. This hypothesis was proven experimentally. Glycation of α-synuclein resulted in increase of GAPDH inactivation, and this effect was more pronounced in case of modification by glyceraldehyde-3-phosphate. The obtained results can reflect the probable relations between protein glycation and neurodegenerative diseases.

Topics: alpha-Synuclein; Catalytic Domain; Glycation End Products, Advanced; Glyceraldehyde 3-Phosphate; Glyceraldehyde-3-Phosphate Dehydrogenases; Glycosylation; Humans; Molecular Dynamics Simulation; Neurodegenerative Diseases

Caenorhabditis elegans is widely used to investigate biological processes related to health and disease. Multiple C. elegans models for human neurodegenerative diseases do exist, including those expressing human α-synuclein. Even though these models do not feature all pathological and molecular hallmarks of the disease they mimic, they allow for the identification and dissection of molecular pathways that are involved. In line with this, genetic screens have yielded multiple modifiers of proteotoxicity in C. elegans models for neurodegenerative diseases. Here, we describe a set of common screening approaches and tools that can be used to study synucleinopathies and other neurodegenerative diseases in C. elegans. RNA interference and mutagenesis screens can be used to find genes that affect proteotoxicity, while relatively simple molecular, cellular (fractionation studies), metabolic (respiration studies), and behavioral (thrashing and crawling) readouts can be used to study the effects of disease proteins and modifiers more closely.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Cell Nucleus; Cytosol; Disease Models, Animal; Humans; Neurodegenerative Diseases; Protein Folding; Protein Transport; RNA Interference

Misfolding and aggregation of α-synuclein are linked to many neurodegenerative disorders, including Parkinson's and Alzheimer's disease. Despite intense research efforts, detailed structural characterization of early conformational transitions that initiate and drive α-synuclein aggregation remains elusive often due to the low sensitivity and ensemble averaging of commonly used techniques. Single-molecule Förster resonance energy transfer (smFRET) provides unique advantages in detecting minor conformations that initiate protein pathologic aggregation. In this chapter, we describe an smFRET-based method for characterizing early conformational conversions that are responsible for α-synuclein self-assembly and aggregation.

Topics: alpha-Synuclein; Fluorescence Resonance Energy Transfer; Intrinsically Disordered Proteins; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Conformation; Protein Folding; Spectrum Analysis

Cerebrospinal fluid (CSF) amyloid-β (Aβ)42 and tau are biomarkers for Alzheimer's disease (AD); however, the effects of other neurodegenerative processes on these biomarkers remain unclear. We measured Aβ40, Aβ42, total tau, phosphorylated-tau, and α-synuclein in CSF and plasma using matched samples from various neurodegenerative diseases to expand our basic knowledge on these biomarkers and their practical applications. A total of 213 CSF and 183 plasma samples were analyzed from cognitively unimpaired subjects, and patients with Alzheimer's disease dementia (ADD), mild cognitive impairment (MCI), non-AD dementias, and other neurological diseases. The CSF/plasma ratios of Aβ40 and Aβ42 were approximately 25:1. Aβ40/42 ratios in CSF and plasma were both 10:1. The CSF total tau/P181tau ratio was 6:1. The CSF/plasma α-synuclein ratio was 1:65. Significantly decreased Aβ42 levels and an increased Aβ40/42 ratio in CSF in ADD/MCI suggested that these relationships were specifically altered in AD. Increased total tau levels in ADD/MCI, encephalopathy, and multiple system atrophy, and increased P181tau in ADD/MCI indicated that these biomarkers corresponded to neurodegeneration and tauopathy, respectively. Although CSF α-synuclein levels were increased in ADD/MCI, there was no merit in measuring α-synuclein in CSF or plasma as a biomarker. The combination of biomarkers by the Aβ40/42 ratio×p181tau reflected specific changes due to the AD pathology in ADD/MCI. Thus, CSF Aβ40, Aβ42, p181tau, and tau were identified as biomarkers for aggregated Aβ associated state (A), aggregated tau associated state (T), and neurodegeneration state (N) pathologies in AD based on the NIA-AA criteria. Overlaps in these biomarkers need to be considered in clinical practice for differential diagnoses of neurodegenerative diseases.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Female; Humans; Male; Middle Aged; Neurodegenerative Diseases; Peptide Fragments; tau Proteins; Young Adult

Mutations in the

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Dopaminergic Neurons; Gene Knock-In Techniques; Male; Mice; Mutation; Nervous System Diseases; Neurodegenerative Diseases; Neuropathology; Parkinson Disease; Protein Transport; tau Proteins; Vesicular Transport Proteins

Neurodegenerative diseases like Alzheimer's disease, Parkinson's disease and Huntington's disease manifest with the neuronal accumulation of toxic proteins. Since autophagy upregulation enhances the clearance of such proteins and ameliorates their toxicities in animal models, we and others have sought to re-position/re-profile existing compounds used in humans to identify those that may induce autophagy in the brain. A key challenge with this approach is to assess if any hits identified can induce neuronal autophagy at concentrations that would be seen in humans taking the drug for its conventional indication. Here we report that felodipine, an L-type calcium channel blocker and anti-hypertensive drug, induces autophagy and clears diverse aggregate-prone, neurodegenerative disease-associated proteins. Felodipine can clear mutant α-synuclein in mouse brains at plasma concentrations similar to those that would be seen in humans taking the drug. This is associated with neuroprotection in mice, suggesting the promise of this compound for use in neurodegeneration.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Autophagy; Cell Line; Cerebral Cortex; Disease Models, Animal; Drug Repositioning; Embryo, Mammalian; Embryo, Nonmammalian; Felodipine; Female; Humans; Induced Pluripotent Stem Cells; Male; Mice; Mice, Inbred C57BL; Mutation; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Primary Cell Culture; Swine; Swine, Miniature; Treatment Outcome; Zebrafish

There is increasing evidence suggesting that amyloidogenic proteins might form deposits in non-neuronal tissues in neurodegenerative disorders such as Alzheimer's or Parkinson's diseases. However, the detection of these aggregation-prone proteins within the human skin has been controversial. Using immunohistochemistry (IHC) and mass spectrometry tissue imaging (MALDI-MSI), fresh frozen human skin samples were analyzed for the expression and localization of neurodegenerative disease-related proteins. While α-synuclein was detected throughout the epidermal layer of the auricular samples (IHC and MALDI-MSI), tau and Aβ34 were also localized to the epidermal layer (IHC). In addition to Aβ peptides of varying length (e.g., Aβ40, Aβ42, Aβ34), we also were able to detect inflammatory markers within the same sample sets (e.g., thymosin β-4, psoriasin). While previous literature has described α-synuclein in the nucleus of neurons (e.g., Parkinson's disease), our current detection of α-synuclein in the nucleus of skin cells is novel. Imaging of α-synuclein or tau revealed that their presence was similar between the young and old samples in our present study. Future work may reveal differences relevant for diagnosis between these proteins at the molecular level (e.g., age-dependent post-translational modifications). Our novel detection of Aβ34 in human skin suggests that, just like in the brain, it may represent a stable intermediate of the Aβ40 and Aβ42 degradation pathway.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Child; Epidermis; Female; Humans; Inflammation Mediators; Male; Middle Aged; Neurodegenerative Diseases; Peptide Fragments; Skin; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; 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

Evidence is accumulating to suggest that viral infections and consequent viral-mediated neuroinflammation may contribute to the etiology of idiopathic Parkinson's disease. Moreover, viruses have been shown to influence α-synuclein oligomerization as well as the autophagic clearance of abnormal intra-cellular proteins aggregations, both of which are key neuropathological events in Parkinson's disease pathogenesis. To further investigate the interaction between viral-mediated neuroinflammation and α-synuclein aggregation in the context of Parkinson's disease, this study sought to determine the impact of viral neuroinflammatory priming on α-synuclein aggregate-induced neuroinflammation and neurotoxicity in the rat nigrostriatal pathway. To do so, male Sprague-Dawley rats were intra-nigrally injected with a synthetic mimetic of viral dsRNA (poly I:C) followed two weeks later by a peptidomimetic small molecule which accelerates α-synuclein fibril formation (FN075). The impact of the viral priming on α-synuclein aggregation-induced neuroinflammation, neurodegeneration and motor dysfunction was assessed. We found that prior administration of the viral mimetic poly I:C significantly exacerbated or precipitated the α-synuclein aggregate induced neuropathological and behavioral effects. Specifically, sequential exposure to the two challenges caused a significant increase in nigral microgliosis (p < 0.001) and astrocytosis (p < 0.01); precipitated a significant degeneration of the nigrostriatal cell bodies (p < 0.05); and precipitated a significant impairment in forelimb kinesis (p < 0.01) and sensorimotor integration (p < 0.01). The enhanced sensitivity of the nigrostriatal neurons to pathological α-synuclein aggregation after viral neuroinflammatory priming further suggests that viral infections may contribute to the etiology and pathogenesis of Parkinson's disease.

Topics: alpha-Synuclein; Animals; Biomimetic Materials; Corpus Striatum; Dependovirus; Disease Models, Animal; Genetic Vectors; Gliosis; Male; Motor Activity; Neurodegenerative Diseases; Neuroimmunomodulation; Neurons; Parkinson Disease; Poly I-C; Protein Aggregation, Pathological; Rats; Rats, Sprague-Dawley; Substantia Nigra; Tyrosine 3-Monooxygenase

Permethrin is a synthetic pyrethroid extensively used as anti-woodworm agent and for indoor and outdoor pest control. The main route of human exposure is through fruit, vegetable and milk intake. Low dosage exposure to permethrin during neonatal brain development (from postnatal day 6 to postnatal day 21) leads to dopamine decrease in rat striatum nucleus, oxidative stress and behavioural changes linked to the development of Parkinson's like neurodegeneration later in life. The aim of this study was to evaluate the expression of genes involved in the dopaminergic pathway and epigenetic regulatory mechanisms in adolescent rats treated with permethrin during neonatal brain development. Furthermore, in order to shed light on the mechanisms associated with molecular impairments, in silico studies were performed. The outcomes show increased expression of genes related to the dopamine-synthesis pathway (Nurr1, Th, Snca), epigenetics (TET proteins and Mecp2) and exposure to toxicants (Pon1 and Pon2) in adolescent rats compared with control group. Furthermore, increased global 5mC and 5hmC levels were observed in the DNA extracted from striatum of early-life treated rats in comparison with controls. FAIRE-qPCR analysis shows that permethrin induces an enrichment of chromatin-free DNA at the level of Th and Nurr1 promoters, and ChIP-qPCR reveals a significant reduction in methylation levels at H3K9me3 position at both Th and Nurr1 promoter regions. In silico studies show that permethrin competes for the same two binding sites of known NURR1 agonists, with a lower binding free energy for permethrin, suggesting an important durable association of permethrin with the orphan receptor. Moreover, alpha-synuclein shows a strong affinity for NURR1, corroborating previous experimental outcomes on the interactions between them. This study focuses on an emerging role of early-life exposure to environmental pollutants in the regulation of late onset diseases through intriguing mechanisms that change crucial epigenetic patterns starting from adolescent age.

Topics: Aging; alpha-Synuclein; Animals; Animals, Newborn; Corpus Striatum; DNA Methylation; DNA Modification Methylases; Dopamine; Epigenesis, Genetic; Male; Molecular Docking Simulation; Neurodegenerative Diseases; Nuclear Receptor Subfamily 4, Group A, Member 2; Permethrin; Promoter Regions, Genetic; Protein Multimerization; Rats; Rats, Wistar

Rapid eye movement (REM) sleep without atonia (RWA) is the main polysomnographic feature of idiopathic REM sleep behavior disorder (iRBD) and is considered to be a promising biomarker predicting conversion to manifested synucleinopathy. Besides conventionally evaluated tonic, phasic and any RWA, we took into consideration also periods, when phasic and tonic RWA appeared simultaneously and we called this activity "mixed RWA." The study aimed to evaluate different types of RWA, to reveal the most relevant biomarker to the conversion.. A total of 55 patients with confirmed iRBD were recruited with mean follow-up duration 2.3 ± 0.7 years. Scoring of RWA was based on Sleep Innsbruck Barcelona rules. Positive phenocoversion was ascertained according to standard diagnostic criteria during follow-up. Receiver operator characteristic analysis was applied to evaluate predictive performance of different RWA types.. A total of nine patients (16%) developed neurodegenerative diseases. Yearly phenoconversion rate was 5.5%. Significantly higher amounts of mixed (p = 0.009), tonic (p = 0.020), and any RWA (p = 0.049) were found in converters. Optimal cutoffs differentiating the prediction were 16.4% (sensitivity 88.9; specificity 69.6) for tonic, 4.4% (sensitivity 88.9; specificity 60.9) for mixed, and 36.8% (sensitivity 77.8; specificity 65.2) for any RWA. With area under the curve (AUC) 0.778, mixed RWA has proven to be the best predictive test followed by tonic (AUC 0.749) and any (AUC 0.710).. Mixed, tonic and any RWA may serve as biomarkers predicting the conversion into neurodegenerative disease in iRBD. The best predictive value lies within mixed RWA, thus it should be considered as standard biomarker.

Topics: Aged; alpha-Synuclein; Biomarkers; Caffeine; Data Collection; Female; Humans; Male; Middle Aged; Muscle Hypotonia; Neurodegenerative Diseases; Polysomnography; REM Sleep Behavior Disorder; ROC Curve; Sleep, REM; Synucleinopathies

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Drug Discovery; GPI-Linked Proteins; Humans; Neurodegenerative Diseases; Prions

α-Synucleinopathies are neurodegenerative diseases that are characterized pathologically by α-synuclein inclusions in neurons and glia. The pathologic contribution of glial α-synuclein in these diseases is not well understood. Glial α-synuclein may be of particular importance in multiple system atrophy (MSA), which is defined pathologically by glial cytoplasmic α-synuclein inclusions. We have previously described Drosophila models of neuronal α-synucleinopathy, which recapitulate key features of the human disorders. We have now expanded our model to express human α-synuclein in glia. We demonstrate that expression of α-synuclein in glia alone results in α-synuclein aggregation, death of dopaminergic neurons, impaired locomotor function, and autonomic dysfunction. Furthermore, co-expression of α-synuclein in both neurons and glia worsens these phenotypes as compared to expression of α-synuclein in neurons alone. We identify unique transcriptomic signatures induced by glial as opposed to neuronal α-synuclein. These results suggest that glial α-synuclein may contribute to the burden of pathology in the α-synucleinopathies through a cell type-specific transcriptional program. This new Drosophila model system enables further mechanistic studies dissecting the contribution of glial and neuronal α-synuclein in vivo, potentially shedding light on mechanisms of disease that are especially relevant in MSA but also the α-synucleinopathies more broadly.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Cell Death; Constipation; Disease Models, Animal; Dopaminergic Neurons; Drosophila; Humans; Movement Disorders; Nerve Degeneration; Neurodegenerative Diseases; Neuroglia; Protein Aggregation, Pathological; Transcription, Genetic; Transcriptome

Topics: alpha-Synuclein; Amyloid beta-Peptides; Cells, Cultured; Chromatography, Liquid; Humans; Kynurenine; Magnetic Resonance Spectroscopy; Neurodegenerative Diseases; Neurons; Peptide Fragments; Tandem Mass Spectrometry

Topics: alpha-Synuclein; Cytokines; Humans; Inflammation Mediators; Microglia; Models, Biological; Molecular Structure; Neurodegenerative Diseases; Neurons; Phosphatidylinositol 3-Kinases; Receptors, Purinergic P2X7; Rifampin; Signal Transduction; Toll-Like Receptor 2

Moderate physical exercise acts at molecular and behavioural levels, such as interfering in neuroplasticity, cell death, neurogenesis, cognition and motor functions. Therefore, the aim of this study is to analyse the cellular effects of moderate treadmill running upon substantia nigra during early neurodegeneration. Aged male Lewis rats (9-month-old) were exposed to rotenone 1mg/kg/day (8 weeks) and 6 weeks of moderate treadmill running, beginning 4 weeks after rotenone exposure. Substantia nigra was extracted and submitted to proteasome and antioxidant enzymes activities, hydrogen peroxide levels and Western blot to evaluate tyrosine hydroxylase (TH), alpha-synuclein, Tom-20, PINK1, TrkB, SLP1, CRMP-2, Rab-27b, LC3II and Beclin-1 level. It was demonstrated that moderate treadmill running, practiced during early neurodegeneration, prevented the increase of alpha-synuclein and maintained the levels of TH unaltered in substantia nigra of aged rats. Physical exercise also stimulated autophagy and prevented impairment of mitophagy, but decreased proteasome activity in rotenone-exposed aged rats. Physical activity also prevented H

Topics: alpha-Synuclein; Animals; Autophagy; Disease Models, Animal; Hydrogen Peroxide; Male; Mitophagy; Neurodegenerative Diseases; Physical Conditioning, Animal; Proteasome Endopeptidase Complex; Rats, Inbred Lew; Rotenone; Running; Substantia Nigra; Tyrosine 3-Monooxygenase

In the adult mammalian hippocampus, new neurons are constantly added to the dentate gyrus. Adult neurogenesis is impaired in several neurodegenerative mouse models including α-synuclein (a-syn) transgenic mice. Among different a-syn species, a-syn oligomers were reported to be the most toxic species for neurons. Here, we studied the impact of wild-type vs. oligomer-prone a-syn on neurogenesis. We compared the wild-type a-syn transgenic mouse model (Thy1-WTS) to its equivalent transgenic for oligomer-prone E57K-mutant a-syn (Thy1-E57K). Transgenic a-syn was highly expressed within the hippocampus of both models, but was not present within adult neural stem cells and neuroblasts. Proliferation and survival of newly generated neurons were unchanged in both transgenic models. Thy1-WTS showed a minor integration deficit regarding mushroom spine density of newborn neurons, whereas Thy1-E57K exhibited a severe reduction of all spines. We conclude that cell-extrinsic a-syn impairs mushroom spine formation of adult newborn neurons and that oligomer-prone a-syn exacerbates this integration deficit. Moreover, our data suggest that a-syn reduces the survival of newborn neurons by a cell-intrinsic mechanism during the early neuroblast development. The finding of increased spine pathology in Thy1-E57K is a new pathogenic function of oligomeric a-syn and precedes overt neurodegeneration. Thus, it may constitute a readout for therapeutic approaches.

Topics: alpha-Synuclein; Animals; Bromodeoxyuridine; Caspase 3; Cell Proliferation; Disease Models, Animal; Doublecortin Domain Proteins; Gene Expression Regulation; Glutamic Acid; Hippocampus; Lysine; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microtubule-Associated Proteins; Mutation; Neurodegenerative Diseases; Neurogenesis; Neurons; Neuropeptides; Phosphopyruvate Hydratase; SOXB1 Transcription Factors

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

Long non-coding RNAs (lncRNAs) are a new research focus that are reported to influence the pathogenetic process of neurodegenerative disorders. To uncover new disease-associated genes and their relevant mechanisms, we carried out a gene microarray analysis based on a Parkinson's disease (PD) in vitro model induced by α-synuclein oligomers. This cellular model induced by 25 μmol/L α-synuclein oligomers has been confirmed to show the stable, transmissible neurotoxicity of α-synuclein, a typical PD pathological marker. And several differentially expressed lncRNAs and mRNAs were identified in this model, such as G046036, G030771, AC009365.4, RPS14P3, CTB-11I22.1, and G007549. Subsequent ceRNA analysis determined the potential relationships between these lncRNAs and their associated mRNAs and microRNAs. The results of the present study widen our horizon of PD susceptibility genes and provide new pathways towards efficient diagnostic biomarkers and therapeutic targets for PD.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Cerebral Cortex; Cohort Studies; Female; Humans; Male; Microarray Analysis; MicroRNAs; Neurodegenerative Diseases; Parkinson Disease; RNA, Long Noncoding; RNA, Messenger

Parkinson's disease is characterized by degeneration of substantia nigra dopamine neurons and by intraneuronal aggregates, primarily composed of misfolded α-synuclein. The α-synuclein aggregates in Parkinson's patients are suggested to first appear in the olfactory bulb and enteric nerves and then propagate, following a stereotypic pattern, via neural pathways to numerous regions across the brain. We recently demonstrated that after injection of either mouse or human α-synuclein fibrils into the olfactory bulb of wild-type mice, α-synuclein fibrils recruited endogenous α-synuclein into pathological aggregates that spread transneuronally to over 40 other brain regions and subregions, over 12 months. We previously reported the progressive spreading of α-synuclein aggregates, between 1 and 12 months following α-synuclein fibril injections, and now report how far the pathology has spread 18- and 23-month post-injection in this model. Our data show that between 12 and 18 months, there is a further increase in the number of brain regions exhibiting pathology after human, and to a lesser extent mouse, α-synuclein fibril injections. At both 18 and 23 months after injection of mouse and human α-synuclein fibrils, we observed a reduction in the density of α-synuclein aggregates in some brain regions compared to others at 12 months. At 23 months, no additional brain regions exhibited α-synuclein aggregates compared to earlier time points. In addition, we also demonstrate that the induced α-synucleinopathy triggered a significant early neuron loss in the anterior olfactory nucleus. By contrast, there was no loss of mitral neurons in the olfactory bulb, even at 18 month post-injection. We speculate that the lack of continued progression of α-synuclein pathology is due to compromise of the neural circuitry, consequential to neuron loss and possibly to the activation of proteolytic mechanisms in resilient neurons of wild-type mice that counterbalances the spread and seeding by degrading pathogenic α-synuclein.

Topics: alpha-Synuclein; Animals; Biological Transport; Brain; Cell Death; Disease Models, Animal; Disease Progression; DNA-Binding Proteins; Female; Humans; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Olfactory Bulb; Protein Aggregation, Pathological; Recombinant Proteins; tau Proteins

α-synuclein (αS) is a small protein that self-aggregates into α-helical oligomer species and subsequently into larger insoluble amyloid fibrils that accumulate in intraneuronal inclusions during the development of Parkinson's disease. Toxicity of αS oligomers and fibrils has been long debated and more recent data are suggesting that both species can induce neurodegeneration. However while most of these data are based on differences in structure between oligomer and aggregates, often preassembled in vitro, the in vivo situation might be more complex and subcellular locations where αS species accumulate, rather than their conformation, might contribute to enhanced toxicity. In line with this observation, we have shown that αS oligomers and aggregates are associated with the endoplasmic reticulum/microsomes (ER/M) membrane in vivo and how accumulation of soluble αS oligomers at the ER/M level precedes neuronal degeneration in a mouse model of α-synucleinopathies. In this paper we took a further step, investigating the biochemical and functional features of αS species associated with the ER/M membrane. We found that by comparison with non-microsomal associated αS (P10), the ER/M-associated αS pool is a unique population of oligomers and aggregates with specific biochemical traits such as increased aggregation, N- and C-terminal truncations and phosphorylation at serine 129. Moreover, when administered to murine primary neurons, ER/M-associated αS species isolated from diseased A53T human αS transgenic mice induced neuronal changes in a time- and dose-dependent manner. In fact the addition of small amounts of ER/M-associated αS species from diseased mice to primary cultures induced the formation of beads-like structures or strings of fibrous αS aggregates along the neurites, occasionally covering the entire process or localizing at the soma level. By comparison treatment with P10 fractions from the same diseased mice resulted in the formation of scarce and small puncta only when administered at high amount. Moreover, increasing the amount of P100/M fractions obtained from diseased and, more surprisingly, from presymptomatic mice induced a significant level of neuronal death that was prevented when neurons were treated with ER/M fractions immunodepleted of αS high molecular weight (HMW) species. These data provide the first evidence of the existence of two different populations of αS HMW species in vivo, putting the spotlight on the association to ER/M membrane

Topics: alpha-Synuclein; Animals; Apoptosis; Cell Line, Tumor; Cerebral Cortex; Disease Models, Animal; Endoplasmic Reticulum; Humans; Mice, Transgenic; Microsomes; Molecular Weight; Nerve Degeneration; Neurodegenerative Diseases; Neurons; Primary Cell Culture; Protein Aggregation, Pathological

Topics: alpha-Synuclein; Animals; Female; Glucans; Humans; Immunity, Cellular; Immunity, Humoral; Immunosuppressive Agents; Male; Mice; Mice, Transgenic; Nanoparticles; Neurodegenerative Diseases; Sirolimus; T-Lymphocytes, Regulatory; Vaccination

See Attems and Jellinger (doi:10.1093/brain/awx360) for a scientific commentary on this article.Cognitive changes occurring throughout the pathogenesis of neurodegenerative diseases are directly linked to synaptic loss. We used in-depth proteomics to compare 32 post-mortem human brains in the prefrontal cortex of prospectively followed patients with Alzheimer's disease, Parkinson's disease with dementia, dementia with Lewy bodies and older adults without dementia. In total, we identified 10 325 proteins, 851 of which were synaptic proteins. Levels of 25 synaptic proteins were significantly altered in the various dementia groups. Significant loss of SNAP47, GAP43, SYBU (syntabulin), LRFN2, SV2C, SYT2 (synaptotagmin 2), GRIA3 and GRIA4 were further validated on a larger cohort comprised of 92 brain samples using ELISA or western blot. Cognitive impairment before death and rate of cognitive decline significantly correlated with loss of SNAP47, SYBU, LRFN2, SV2C and GRIA3 proteins. Besides differentiating Parkinson's disease dementia, dementia with Lewy bodies, and Alzheimer's disease from controls with high sensitivity and specificity, synaptic proteins also reliably discriminated Parkinson's disease dementia from Alzheimer's disease patients. Our results suggest that these particular synaptic proteins have an important predictive and discriminative molecular fingerprint in neurodegenerative diseases and could be a potential target for early disease intervention.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Brain; Cognition Disorders; Female; Gene Expression Regulation; Humans; Intracellular Signaling Peptides and Proteins; Male; Membrane Proteins; Microtubule-Associated Proteins; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurologic Examination; Neuropsychological Tests; Proteomics; Synapses

Mutations in LRRK2 are known to be the most common genetic cause of sporadic and familial Parkinson's disease (PD). Multiple lines of LRRK2 transgenic or knockin mice have been developed, yet none exhibit substantial dopamine (DA)-neuron degeneration. Here we develop human tyrosine hydroxylase (TH) promoter-controlled tetracycline-sensitive LRRK2 G2019S (GS) and LRRK2 G2019S kinase-dead (GS/DA) transgenic mice and show that LRRK2 GS expression leads to an age- and kinase-dependent cell-autonomous neurodegeneration of DA and norepinephrine (NE) neurons. Accompanying the loss of DA neurons are DA-dependent behavioral deficits and α-synuclein pathology that are also LRRK2 GS kinase-dependent. Transmission EM reveals that that there is an LRRK2 GS kinase-dependent significant reduction in synaptic vesicle number and a greater abundance of clathrin-coated vesicles in DA neurons. These transgenic mice indicate that LRRK2-induced DA and NE neurodegeneration is kinase-dependent and can occur in a cell-autonomous manner. Moreover, these mice provide a substantial advance in animal model development for LRRK2-associated PD and an important platform to investigate molecular mechanisms for how DA neurons degenerate as a result of expression of mutant LRRK2.

Topics: Age Factors; alpha-Synuclein; Animals; Behavior, Animal; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Male; Mice; Mice, Transgenic; Motor Activity; Mutation; Neurodegenerative Diseases; Norepinephrine

Topics: alpha-Synuclein; Brain; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; tau Proteins

Recombinant adeno-associated virus (AAV) vectors are a popular genetic approach in neuroscience because they confer such efficient transgene expression in the brain and spinal cord. A number of studies have used AAV to express pathological disease-related proteins in the dopaminergic neurons of the substantia nigra in situ ( e.g., α-synuclein to model aspects of Parkinson's disease). The neuropathology and neurodegeneration of Parkinson's disease occur in a circumscribed pattern in the brain, and one of the most important goals of any gene transfer study is accurate, pinpoint targeting. By combining Cre recombinase-dependent AAVs in Cre-driver rats in which Cre is expressed only in the tyrosine hydroxylase neurons, we have achieved more highly targeted expression of several disease-relevant neuropathological proteins in the substantia nigra pars compacta than using constitutive expression AAV vectors. Alpha-synuclein, tau, transactive response DNA-binding protein of 43 kDa, or the control fluorescent protein yellow fluorescent protein was individually expressed to induce highly targeted, dopaminergic neuron-specific neurodegeneration models. The refined targeting foreshadows a next-generation disease modeling system for expressing neurodegenerative disease-related proteins in a disease-relevant manner. We foresee specific utilities of this in vivo AAV vector targeting of pathological proteins to a well-defined and well-demarcated cell population.-Grames, M. S., Dayton, R. D., Jackson, K. L., Richard, A. D., Lu, X., Klein, R. L. Cre-dependent AAV vectors for highly targeted expression of disease-related proteins and neurodegeneration in the substantia nigra.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopaminergic Neurons; Female; Genetic Vectors; Integrases; Neurodegenerative Diseases; Rats; Substantia Nigra

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the degeneration of dopaminergic neurons of the substantia nigra and the accumulation of protein aggregates, called Lewy bodies, where the most abundant is alpha-synuclein (α-SYN). Mutations of the gene that codes for α-SYN (SNCA), such as the A53T mutation, and duplications of the gene generate cases of PD with autosomal dominant inheritance. As a result of the association of inflammation with the neurodegeneration of PD, we analyzed whether overexpression of wild-type α-SYN (α-SYN

Topics: alpha-Synuclein; Animals; Chemokine CX3CL1; Disease Models, Animal; Dopaminergic Neurons; Mice, Knockout; Microglia; Neurodegenerative Diseases; Parkinson Disease; Substantia Nigra

Current therapeutic strategies to treat neurodegenerative diseases, such as alpha-synucleinopathies, aim at enhancing the amount of drug reaching the brain. Methods proposed, such as intranasal administration, should be able to bypass the blood brain barrier (BBB) and even when directly intracerebrally injected they could require a carrier to enhance local release of drugs. We have investigated the effect of a model synthetic hydrogel to be used as drug carrier on the amount of alpha-synuclein aggregates in cells in culture. The results indicated that alpha-synuclein aggregation was affected by the synthetic polymer, suggesting the need for testing the effect of any used material on the pathological process before its application as drug carrier.

Topics: alpha-Synuclein; Blood-Brain Barrier; Brain; Cell Line, Tumor; Drug Carriers; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate; Neurodegenerative Diseases; Polymers

Neurogranin (Ng) is a post-synaptic protein that previously has been shown to be a biomarker for synaptic function when measured in cerebrospinal fluid (CSF). The CSF concentration of Ng is increased in Alzheimer's disease dementia (ADD), and even in the pre-dementia stage. In this prospective study, we used an enzyme-linked immunosorbent assay that quantifies Ng in CSF to test the performance of Ng as a marker of synaptic function. In 915 patients, CSF Ng was evaluated across several different neurodegenerative diseases. Of these 915 patients, 116 had a neuropathologically confirmed definitive diagnosis and the relation between CSF Ng and topographical distribution of different pathologies in the brain was evaluated. CSF Ng was specifically increased in ADD compared to eight other neurodegenerative diseases, including Parkinson's disease (p < 0.0001), frontotemporal dementia (p < 0.0001), and amyotrophic lateral sclerosis (p = 0.0002). Similar results were obtained in neuropathologically confirmed cases. Using a biomarker index to evaluate whether CSF Ng contributed diagnostic information to the core AD CSF biomarkers (amyloid β (Aβ), t-tau, and p-tau), we show that Ng significantly increased the discrimination between AD and several other disorders. Higher CSF Ng levels were positively associated with greater Aβ neuritic plaque (Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuritic plaque score, p = 0.0002) and tau tangle pathology (Braak neurofibrillary tangles staging, p = 0.0007) scores. In the hippocampus and amygdala, two brain regions heavily affected in ADD with high expression of Ng, CSF Ng was associated with plaque (p = 0.0006 and p < 0.0001), but not with tangle, α-synuclein, or TAR DNA-binding protein 43 loads. These data support that CSF Ng is increased specifically in ADD, that high CSF Ng concentrations likely reflect synaptic dysfunction and that CSF Ng is associated with β-amyloid plaque pathology.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Female; Hippocampus; Humans; Male; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurogranin; Phenotype; Prospective Studies; tau Proteins

Proteostasis is critical to maintain organismal viability, a process counteracted by aging-dependent protein aggregation. Chaperones of the heat shock protein (HSP) family help control proteostasis by reducing the burden of unfolded proteins. They also oversee the formation of protein aggregates. Here, we explore how AMPylation, a posttranslational protein modification that has emerged as a powerful modulator of HSP70 activity, influences the dynamics of protein aggregation. We find that adjustments of cellular AMPylation levels in

Topics: Adenosine Monophosphate; alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; HSP70 Heat-Shock Proteins; Molecular Chaperones; Neurodegenerative Diseases; Nucleotidyltransferases; Peptides; Protein Aggregation, Pathological; Protein Processing, Post-Translational; Proteostasis

Parkinson's disease (PD) is the second most common neurodegenerative disorder and it is characterized by progressive physical disability along with a variety of non-motor symptoms. Drugs that replenish dopamine can partly alleviate the motor symptoms; however, they do not cure the disease itself. Therefore, there is an urgent need for disease modifying therapies that would delay or prevent neurodegeneration. Increasing evidence suggests that α-synuclein, a key molecule in PD, is secreted into the extracellular environment and can be transported from cell-to-cell, thereby affecting the physiological state of the neighboring cells in a prion-like manner. Given the potential role of extracellular α-synuclein as the cause of disease progression, its prion-like propagation is a promising target for developing disease-modifying therapies for PD and other synucleinopathies.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease; Prions; Transcytosis

Lewy bodies commonly occur in Alzheimer's disease, and Alzheimer's disease pathology is frequent in Lewy body diseases, but the burden of co-pathologies across neurodegenerative diseases is unknown. We assessed the extent of tau, amyloid-β, α-synuclein and TDP-43 proteinopathies in 766 autopsied individuals representing a broad spectrum of clinical neurodegenerative disease. We interrogated pathological Alzheimer's disease (n = 247); other tauopathies (n = 95) including Pick's disease, corticobasal disease and progressive supranuclear palsy; the synucleinopathies (n = 164) including multiple system atrophy and Lewy body disease; the TDP-43 proteinopathies (n = 188) including frontotemporal lobar degeneration with TDP-43 inclusions and amyotrophic lateral sclerosis; and a minimal pathology group (n = 72). Each group was divided into subgroups without or with co-pathologies. Age and sex matched logistic regression models compared co-pathology prevalence between groups. Co-pathology prevalence was similar between the minimal pathology group and most neurodegenerative diseases for each proteinopathy: tau was nearly universal (92-100%), amyloid-β common (20-57%); α-synuclein less common (4-16%); and TDP-43 the rarest (0-16%). In several neurodegenerative diseases, co-pathology increased: in Alzheimer's disease, α-synuclein (41-55%) and TDP-43 (33-40%) increased; in progressive supranuclear palsy, α-synuclein increased (22%); in corticobasal disease, TDP-43 increased (24%); and in neocortical Lewy body disease, amyloid-β (80%) and TDP-43 (22%) increased. Total co-pathology prevalence varied across groups (27-68%), and was increased in high Alzheimer's disease, progressive supranuclear palsy, and neocortical Lewy body disease (70-81%). Increased age at death was observed in the minimal pathology group, amyotrophic lateral sclerosis, and multiple system atrophy cases with co-pathologies. In amyotrophic lateral sclerosis and neocortical Lewy body disease, co-pathologies associated with APOE ɛ4. Lewy body disease cases with Alzheimer's disease co-pathology had substantially lower Mini-Mental State Examination scores than pure Lewy body disease. Our data imply that increased age and APOE ɛ4 status are risk factors for co-pathologies independent of neurodegenerative disease; that neurodegenerative disease severity influences co-pathology as evidenced by the prevalence of co-pathology in high Alzheimer's disease and neocortical Lewy body disease, but not intermediate

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Amyotrophic Lateral Sclerosis; Apolipoprotein E4; DNA-Binding Proteins; Female; Humans; Inclusion Bodies; Lewy Bodies; Lewy Body Disease; Male; Middle Aged; Multiple System Atrophy; Neurodegenerative Diseases; Pick Disease of the Brain; Prevalence; Supranuclear Palsy, Progressive; tau Proteins; Tauopathies; TDP-43 Proteinopathies

Prion-like propagation of protein aggregates is thought to be an essential feature in many neurodegenerative diseases, but the mechanisms underlying transcellular transfer of protein aggregates remain unclear. Stopschinski

Topics: alpha-Synuclein; Amyloid beta-Peptides; Glycosaminoglycans; Heparan Sulfate Proteoglycans; Humans; Neurodegenerative Diseases; Sulfur; tau Proteins

α-Synuclein (α-Syn) aggregation, proceeding from oligomers to fibrils, is one central hallmark of neurodegeneration in synucleinopathies. α-Syn oligomers are toxic by triggering neurodegenerative processes in in vitro and in vivo models. However, the precise contribution of α-Syn oligomers to neurite pathology in human neurons and the underlying mechanisms remain unclear. Here, we demonstrate the formation of oligomeric α-Syn intermediates and reduced axonal mitochondrial transport in human neurons derived from induced pluripotent stem cells (iPSC) from a Parkinson's disease patient carrying an α-Syn gene duplication. We further show that increased levels of α-Syn oligomers disrupt axonal integrity in human neurons. We apply an α-Syn oligomerization model by expressing α-Syn oligomer-forming mutants (E46K and E57K) and wild-type α-Syn in human iPSC-derived neurons. Pronounced α-Syn oligomerization led to impaired anterograde axonal transport of mitochondria, which can be restored by the inhibition of α-Syn oligomer formation. Furthermore, α-Syn oligomers were associated with a subcellular relocation of transport-regulating proteins Miro1, KLC1, and Tau as well as reduced ATP levels, underlying axonal transport deficits. Consequently, reduced axonal density and structural synaptic degeneration were observed in human neurons in the presence of high levels of α-Syn oligomers. Together, increased dosage of α-Syn resulting in α-Syn oligomerization causes axonal transport disruption and energy deficits, leading to synapse loss in human neurons. This study identifies α-Syn oligomers as the critical species triggering early axonal dysfunction in synucleinopathies.

Topics: alpha-Synuclein; Axonal Transport; Axons; Cell Line; Energy Metabolism; Humans; Induced Pluripotent Stem Cells; Kinesins; Microtubule-Associated Proteins; Mitochondria; Mitochondrial Proteins; Models, Biological; Mutation, Missense; Neurodegenerative Diseases; Protein Multimerization; rho GTP-Binding Proteins; tau Proteins

At present, the precise physiological role of neurodegenerative disease-related amyloidogenic proteins (APs), including α-synuclein in Parkinson's disease and β-amyloid in Alzheimer's disease, remains unclear. Because of similar adaptability of both human brain neurons and yeast cells to diverse environmental stressors, we previously proposed that the concept of evolvability in yeast prion could also be applied to APs in human brain. However, the mechanistic relevance of evolvability to neurodegenerative disorders is elusive. Therefore, our objective is to discuss our hypothesis that evolvability and neurodegenerative disease may represent a form of antagonistic pleiotropy derived from the aggregates of APs. Importantly, such a perspective may provide an outlook of the entire course of sporadic neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloidogenic Proteins; Brain; Humans; Neurodegenerative Diseases; Neurons

Aging is the most prominent risk factor for most neurodegenerative diseases. However, incorporating aging-related changes into models of neurodegeneration rarely occurs. One of the significant changes that occurs in the brain as we age is the shift in phenotype of the resident microglia population to one less able to respond to deleterious changes in the brain. These microglia are termed dystrophic microglia. In order to better model neurodegenerative diseases, we have developed a method to convert microglia into a senescent phenotype in vitro. Mouse microglia grown in high iron concentrations showed many characteristics of dystrophic microglia including, increased iron storage, increased expression of proteins, such as ferritin and the potassium channel, Kv1.3, increased reactive oxygen species production and cytokine release. We have applied this new model to the study of α-synuclein, a protein that is closely associated with a number of neurodegenerative diseases. We have shown that conditioned medium from our model dystrophic microglia increases α-synuclein transcription and expression via tumor necrosis factor alpha (TNFα) and mediated through nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). The conditioned medium also decreases the formation of α-synuclein tetramers, associated ferrireductase activity, and increases aggregates of α-synuclein. The results suggest that we have developed an interesting new model of aged microglia and that factors, including TNFα released from dystrophic microglia could have a significant influence on the pathogenesis of α-synuclein related diseases.

Topics: alpha-Synuclein; Animals; Cell Death; Cell Line, Tumor; Cell Proliferation; Cellular Senescence; Gene Expression Regulation; Humans; Mice; Microglia; Neurodegenerative Diseases; Phenotype; Promoter Regions, Genetic; Protein Aggregates; Tumor Necrosis Factor-alpha

AEP is an age-dependent lysosomal asparaginyl endopeptidase that cleaves numerous substrates including tau and α-synuclein and mediates their pathological roles in neurodegenerative diseases. However, the molecular mechanism regulating this critical protease remains incompletely understood. Here, we show that Akt phosphorylates AEP on residue T322 upon brain-derived neurotrophic factor (BDNF) treatment and triggers its lysosomal translocation and inactivation. When BDNF levels are reduced in neurodegenerative diseases, AEP T322 phosphorylation is attenuated. Consequently, AEP is activated and translocates into the cytoplasm, where it cleaves both tau and α-synuclein. Remarkably, the unphosphorylated T322A mutant increases tau or α-synuclein cleavage by AEP and augments cell death, whereas phosphorylation mimetic T322E mutant represses these effects. Interestingly, viral injection of T322E into Tau P301S mice antagonizes tau N368 cleavage and tau pathologies, rescuing synaptic dysfunction and cognitive deficits. By contrast, viral administration of T322A into young α-SNCA mice elicits α-synuclein N103 cleavage and promotes dopaminergic neuronal loss, facilitating motor defects. Therefore, our findings support the notion that BDNF contributes to the pathogenesis of neurodegenerative diseases by suppressing AEP via Akt phosphorylation.

Topics: alpha-Synuclein; Animals; Brain; Brain-Derived Neurotrophic Factor; Cell Line, Tumor; Cysteine Endopeptidases; Disease Models, Animal; HEK293 Cells; Humans; Lysosomes; Mice; Mice, Knockout; Mutation; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Phosphorylation; Primary Cell Culture; Proto-Oncogene Proteins c-akt; Rats; Recombinant Proteins; tau Proteins

The deposition of pathologic misfolded proteins in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, frontotemporal dementia and amyotrophic lateral sclerosis is hypothesized to burden protein homeostatic (proteostatic) machinery, potentially leading to insufficient capacity to maintain the proteome. This hypothesis has been supported by previous work in our laboratory, as evidenced by the perturbation of cytosolic protein solubility in response to amyloid plaques in a mouse model of Alzheimer's amyloidosis. In the current study, we demonstrate changes in proteome solubility are a common pathology to mouse models of neurodegenerative disease. Pathological accumulations of misfolded tau, α-synuclein and mutant superoxide dismutase 1 in CNS tissues of transgenic mice were associated with changes in the solubility of hundreds of CNS proteins in each model. We observed that changes in proteome solubility were progressive and, using the rTg4510 model of inducible tau pathology, demonstrated that these changes were dependent upon sustained expression of the primary pathologic protein. In all of the models examined, changes in proteome solubility were robust, easily detected, and provided a sensitive indicator of proteostatic disruption. Interestingly, a subset of the proteins that display a shift towards insolubility were common between these different models, suggesting that a specific subset of the proteome is vulnerable to proteostatic disruption. Overall, our data suggest that neurodegenerative proteinopathies modeled in mice impose a burden on the proteostatic network that diminishes the ability of neural cells to prevent aberrant conformational changes that alter the solubility of hundreds of abundant cellular proteins.

Topics: Age Factors; alpha-Synuclein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Central Nervous System; Chromatography, High Pressure Liquid; Disease Models, Animal; Female; Humans; Male; Mice; Mice, Transgenic; Mutation; Neurodegenerative Diseases; Neurofibrillary Tangles; Presenilin-1; Protein Folding; Proteome; Solubility; Tandem Mass Spectrometry; tau Proteins

Dementia with Lewy bodies (DLB) is characterized by neuronal deficits and

Topics: alpha-Synuclein; Animals; Brain; Ceftriaxone; China; Dementia; Disease Models, Animal; Hippocampus; Lewy Bodies; Lewy Body Disease; Magnetic Resonance Imaging; Male; Neurodegenerative Diseases; Neurons; Rats; Rats, Wistar

Parkinson's disease (PD) is characterized by intracellular alpha-synuclein (α-syn) inclusions, progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNpc), and activation of the innate and adaptive immune systems. Disruption of immune signaling between the central nervous system (CNS) and periphery, such as through targeting the chemokine receptor type 2 (CCR2) or the major histocompatibility complex II (MHCII), is neuroprotective in rodent models of PD, suggesting a key role for innate and adaptive immunity in disease progression. The purpose of this study was to investigate whether genetic knockout or RNA silencing of the class II transactivator (CIITA), a transcriptional co-activator required for MHCII induction, is effective in reducing the neuroinflammation and neurodegeneration observed in an α-syn mouse model of PD.. In vitro, we utilized microglia cultures from WT or CIITA -/- mice treated with α-syn fibrils to investigate inflammatory iNOS expression and antigen processing via immunocytochemistry (ICC). In vivo, an adeno-associated virus (AAV) was used to overexpress α-syn in WT and CIITA -/- mice as a model for PD. Concurrently with AAV-mediated overexpression of α-syn, WT mice received CIITA-targeted shRNAs packaged in lentiviral constructs. Immunohistochemistry and flow cytometry were used to assess inflammation and peripheral cell infiltration at 4 weeks post transduction, and unbiased stereology was used 6 months post transduction to assess neurodegeneration.. Using ICC and DQ-ovalbumin, we show that CIITA -/- microglial cultures failed to upregulate iNOS and MHCII expression, and had decreased antigen processing in response to α-syn fibrils when compared to WT microglia. In vivo, global knock-out of CIITA as well as local knockdown using lentiviral shRNAs targeting CIITA attenuated MHCII expression, peripheral immune cell infiltration, and α-syn-induced neurodegeneration.. Our data provide evidence that CIITA is required for α-syn-induced MHCII induction and subsequent infiltration of peripheral immune cells in an α-syn mouse model of PD. Additionally, we demonstrate that CIITA in the CNS drives neuroinflammation and neurodegeneration. These data provide further support that the disruption or modulation of antigen processing and presentation via CIITA is a promising target for therapeutic development in preclinical animal models of PD.

Topics: alpha-Synuclein; Animals; Antigens, CD; Disease Models, Animal; Encephalitis; Female; Functional Laterality; Gene Expression Regulation, Enzymologic; Green Fluorescent Proteins; Leukocytes, Mononuclear; Male; Mesencephalon; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Nitric Oxide Synthase Type II; Nuclear Proteins; Parkinson Disease; RNA, Small Interfering; Trans-Activators; Tyrosine 3-Monooxygenase

Abnormalities in α-synuclein are implicated in the pathogenesis of Parkinson's disease (PD). Because α-synuclein is highly concentrated within presynaptic terminals, presynaptic dysfunction has been proposed as a potential pathogenic mechanism. Here, we report novel, tau-dependent, postsynaptic deficits caused by A53T mutant α-synuclein, which is linked to familial PD. We analyzed synaptic activity in hippocampal slices and cultured hippocampal neurons from transgenic mice of either sex expressing human WT, A53T, and A30P α-synuclein. Increased α-synuclein expression leads to decreased spontaneous synaptic vesicle release regardless of genotype. However, only those neurons expressing A53T α-synuclein exhibit postsynaptic dysfunction, including decreased miniature postsynaptic current amplitude and decreased AMPA to NMDA receptor current ratio. We also found that long-term potentiation and spatial learning were impaired by A53T α-synuclein expression. Mechanistically, postsynaptic dysfunction requires glycogen synthase kinase 3β-mediated tau phosphorylation, tau mislocalization to dendritic spines, and calcineurin-dependent AMPA receptor internalization. Previous studies reveal that human A53T α-synuclein has a high aggregation potential, which may explain the mutation's unique capacity to induce postsynaptic deficits. However, patients with sporadic PD with severe tau pathology are also more likely to have early onset cognitive decline. Our results here show a novel, functional role for tau: mediating the effects of α-synuclein on postsynaptic signaling. Therefore, the unraveled tau-mediated signaling cascade may contribute to the pathogenesis of dementia in A53T α-synuclein-linked familial PD cases, as well as some subgroups of PD cases with extensive tau pathology.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Cells, Cultured; Excitatory Postsynaptic Potentials; Hippocampus; Humans; Mice; Mice, Transgenic; Mutation; Neurodegenerative Diseases; Organ Culture Techniques; Rats; Synaptic Potentials; tau Proteins

In this paper, the Sequential Collapse Model (SCM) for protein folding pathways is applied to investigate the location of the non-local contacts in the intrinsically disordered state of α-synuclein, a protein implicated in the onset and spreading of several serious neurodegenerative diseases. The model relies on the entropic cost of forming protein loops due to self-crowding effects, and the protein sequence to determine contact location and stability. It is found that the model predicts the existence of several possible non-local contacts, and the location of the non-local contacts is consistent with existing experimental evidence. The bearing of these findings on the pathogenic mechanism and its regulation is discussed.

Topics: alpha-Synuclein; Amino Acid Sequence; Entropy; Humans; Models, Molecular; Mutagenesis, Site-Directed; Neurodegenerative Diseases; Protein Folding; Protein Stability

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

Parkinson's disease and other synucleinopathies are characterized by the accumulation of aggregated α-synuclein in intracellular proteinaceous inclusions. The progressive nature of synucleinopathies seems to be related to the cell-to-cell spreading of α-synuclein pathology, and several possible mechanisms have been put forward to explain this phenomenon. In our recent study, we found that α-synuclein oligomers interact with cellular prion protein in glutamatergic synapses. This interaction triggered a signaling cascade involving phosphorylation of Fyn kinase and activation of the N-methyl-d-aspartate receptor, thereby leading to synaptic dysfunction. Here, we present relevant plasma membrane proteins that have been described to interact with α-synuclein and discuss the possible pathological implications. We focus primarily on the prion protein and propose a pathological mechanism in which the interaction between α-synuclein and prion protein leads to the formation of cofilin/actin rods, culminating in long-term potentiation impairment and cognitive dysfunction. We posit that deciphering the mechanisms involved in sensing specific forms of extracellular α-synuclein and transducing this information may prove invaluable in our quest to devise novel diagnostic and therapeutic approaches in PD and other synucleinopathies. © 2018 International Parkinson and Movement Disorder Society.

Topics: alpha-Synuclein; Animals; Brain; Cognition Disorders; Humans; Models, Biological; Neurodegenerative Diseases; Prion Proteins; Signal Transduction; Synapses

Alpha-synuclein (ASN) is a presynaptic protein that can easily change its conformation under different types of stress. It's assumed that ASN plays an important role in the pathogenesis of Parkinson's and Alzheimer's disease. However, the molecular mechanism of ASN toxicity has not been elucidated. This study focused on the role of extracellular ASN (eASN) in regulation of transcription of sirtuins (Sirts) and DNA-bound poly(ADP-ribose) polymerases (PARPs) - proteins crucial for cells' survival/death. Our results indicate that eASN enhanced the free radicals level, decreased mitochondria membrane potential, cells viability and activated cells' death. Concomitantly eASN activated expression of antioxidative proteins (Sod2, Gpx4, Gadd45b) and DNA-bound Parp2 and Parp3. Moreover, eASN upregulated expression of Sirt3 and Sirt5, but downregulated of Sirt1, which plays an important role in cell metabolism including Aβ precursor protein (APP) processing. eASN downregulated gene expression of APP alpha secretase (Adam10) and metalloproteinases Mmp2, Mmp10 but upregulated Mmp11. Additionally, expression and activity of pro-survival sphingosine kinase 1 (Sphk1), Akt kinase and anti-apoptotic protein Bcl2 were inhibited. Moreover, higher expression of pro-apoptotic protein Bax and enhancement of apoptotic cells' death were observed. Summarizing, eASN significantly modulates transcription of Sirts and enzymes involved in APP/Aβ metabolism and through these mechanisms eASN toxicity may be enhanced. The inhibition of Sphk1 and Akt by eASN may lead to disturbances of survival pathways. These results suggest that eASN through alteration of transcription and by inhibition of pro-survival kinases may play important pathogenic role in neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Antioxidants; Apoptosis; Cell Survival; Gene Expression Regulation; Heat-Shock Proteins; Membrane Potential, Mitochondrial; Neurodegenerative Diseases; PC12 Cells; Phosphorylation; Poly(ADP-ribose) Polymerases; Rats; Reactive Oxygen Species; Sirtuins

To investigate whether cerebrospinal fluid (CSF) biomarkers of neurodegeneration are altered in narcolepsy in order to evaluate whether the hypocretin deficiency and abnormal sleep-wake pattern in narcolepsy leads to neurodegeneration.. Twenty-one patients with central hypersomnia (10 type 1 narcolepsy, 5 type 2 narcolepsy, and 6 idiopathic hypersomnia cases), aged 33 years on average and with a disease duration of 2-29 years, and 12 healthy controls underwent CSF analyses of the levels of β-amyloid, total tau protein (T-tau), phosphorylated tau protein (P-tau181), α-synuclein, neurofilament light chain (NF-L), and chitinase 3-like protein-1 (CHI3L1).. Levels of β-amyloid were lower in patients with type 1 narcolepsy (375.4 ± 143.5 pg/mL) and type 2 narcolepsy (455.9 ± 65.0 pg/mL) compared to controls (697.9 ± 167.3 pg/mL, p < .05). Furthermore, in patients with type 1 narcolepsy, levels of T-tau (79.0 ± 27.5 pg/mL) and P-tau181 (19.1 ± 4.3 pg/mL) were lower than in controls (162.2 ± 49.9 pg/mL and 33.8 ± 9.2 pg/mL, p < .05). Levels of α-synuclein, NF-L, and CHI3L1 in CSF from narcolepsy patients were similar to those of healthy individuals.. Six CSF biomarkers of neurodegeneration were decreased or normal in narcolepsy indicating that taupathy, synucleinopathy, and immunopathy are not prevalent in narcolepsy patients with a disease duration of 2-29 years. Lower CSF levels of β-amyloid, T-tau protein, and P-tau181 in narcolepsy may indicate that hypocretin deficiency and an abnormal sleep-wake pattern alter the turnover of these proteins in the central nervous system.

Topics: Adult; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Case-Control Studies; Chitinase-3-Like Protein 1; Female; Humans; Idiopathic Hypersomnia; Male; Narcolepsy; Neurodegenerative Diseases; Neurofilament Proteins; Orexins; tau Proteins

α-Synuclein misfolding and aggregation is a hallmark in Parkinson's disease and in several other neurodegenerative diseases known as synucleinopathies. The toxic properties of α-synuclein are conserved from yeast to man, but the precise underpinnings of the cellular pathologies associated are still elusive, complicating the development of effective therapeutic strategies. Combining molecular genetics with target-based approaches, we established that glycation, an unavoidable age-associated post-translational modification, enhanced α-synuclein toxicity in vitro and in vivo, in Drosophila and in mice. Glycation affected primarily the N-terminal region of α-synuclein, reducing membrane binding, impaired the clearance of α-synuclein, and promoted the accumulation of toxic oligomers that impaired neuronal synaptic transmission. Strikingly, using glycation inhibitors, we demonstrated that normal clearance of α-synuclein was re-established, aggregation was reduced, and motor phenotypes in Drosophila were alleviated. Altogether, our study demonstrates glycation constitutes a novel drug target that can be explored in synucleinopathies as well as in other neurodegenerative conditions.

Topics: Aging; alpha-Synuclein; Animals; Cell Differentiation; Cell Survival; Cells, Cultured; Disease Models, Animal; Drosophila; Enzyme Inhibitors; Female; Glycosylation; Hippocampus; Humans; Induced Pluripotent Stem Cells; Male; Mice; Mice, Transgenic; Neurodegenerative Diseases; Protein Aggregation, Pathological; Protein Processing, Post-Translational; Pyruvaldehyde; Rats; Yeasts

Mutations in the mitochondrial kinase PTEN-induced putative kinase 1 (PINK1) cause Parkinson's disease (PD), likely by disrupting PINK1's kinase activity. Although the mechanism(s) underlying how this loss of activity causes degeneration remains unclear, increasing PINK1 activity may therapeutically benefit some forms of PD. However, we must first learn whether restoring PINK1 function prevents degeneration in patients harboring PINK1 mutations, or whether boosting PINK1 function can offer protection in more common causes of PD. To test these hypotheses in preclinical rodent models of PD, we used kinetin triphosphate, a small-molecule that activates both wild-type and mutant forms of PINK1, which affects mitochondrial function and protects neural cells in culture. We chronically fed kinetin, the precursor of kinetin triphosphate, to PINK1-null rats in which PINK1 was reintroduced into their midbrain, and also to rodent models overexpressing α-synuclein. The highest tolerated dose of oral kinetin increased brain levels of kinetin for up to 6 months, without adversely affecting the survival of nigrostriatal dopamine neurons. However, there was no degeneration of midbrain dopamine neurons lacking PINK1, which precluded an assessment of neuroprotection and raised questions about the robustness of the PINK1 KO rat model of PD. In two rodent models of α-synuclein-induced toxicity, boosting PINK1 activity with oral kinetin provided no protective effects. Our results suggest that oral kinetin is unlikely to protect against α-synuclein toxicity, and thus fail to provide evidence that kinetin will protect in sporadic models of PD. Kinetin may protect in cases of PINK1 deficiency, but this possibility requires a more robust PINK1 KO model that can be validated by proof-of-principle genetic correction in adult animals.

Topics: Administration, Oral; alpha-Synuclein; Animals; Cells, Cultured; Disease Models, Animal; Drug Administration Schedule; Humans; Kinetin; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Parkinson Disease; Protein Kinases; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Rodentia

α-Synuclein (aSyn), a putative cerebrospinal fluid biomarker, may support the diagnosis of neurodegenerative diseases. Previous studies led to conflicting results due to different preanalytical and analytical procedures. Standardized assays are required to allow for comparison of results from different laboratories.. We performed a side-by-side validation of a commercially available (MSD, MD, USA) and a 'homebrew' assay for quantification of aSyn according to published guidelines.. The data showed high sensitivity and reproducibility for both assays. Preanalytical and analytical parameters did not affect the outcome of measurements.. We conclude that both assays are very close in performance and suitable for research application of cerebrospinal fluid aSyn.

Topics: alpha-Synuclein; Biomarkers; Cohort Studies; Electrochemical Techniques; Enzyme-Linked Immunosorbent Assay; Freezing; Humans; Limit of Detection; Luminescent Measurements; Neurodegenerative Diseases; Parkinson Disease; Reproducibility of Results

Prionoid transmission of α-synuclein (αSyn) aggregates along neuroanatomically connected projections is posited to underlie disease progression in α-synucleinopathies. Here, we specifically wanted to study whether this prionoid progression occurs via direct inter-neuronal transfer and, if so, would intrastriatal injection of αSyn aggregates lead to nigral degeneration.. To test prionoid transmission of αSyn aggregates along the nigro-striatal pathway, we injected amyloidogenic αSyn aggregates into two different regions of the striatum of adult human wild type αSyn transgenic mice (Line M20) or non-transgenic (NTG) mice and aged for 4 months.. M20 mice injected in internal capsule (IC) or caudate putamen (CPu) regions of the striatum showed florid αSyn inclusion pathology distributed throughout the neuraxis, irrespective of anatomic connectivity. These αSyn inclusions were found in different cell types including neurons, astrocytes and even ependymal cells. On the other hand, intra-striatal injection of αSyn fibrils into NTG mice resulted in sparse αSyn pathology, mostly localized in the striatum and entorhinal cortex. Interestingly, NTG mice injected with preformed human αSyn fibrils showed no induction of αSyn inclusion pathology, suggesting the presence of a species barrier for αSyn fibrillar seeds. Modest levels of nigral dopaminergic (DA) neuronal loss was observed exclusively in substantia nigra (SN) of M20 cohorts injected in the IC, even in the absence of frank αSyn inclusions in DA neurons. None of the NTG mice or CPu-injected M20 mice showed DA neurodegeneration. Interestingly, the pattern and distribution of induced αSyn pathology corresponded with neuroinflammation especially in the SN of M20 cohorts. Hypermorphic reactive astrocytes laden with αSyn inclusions were abundantly present in the brains of M20 mice.. Overall, our findings show that the pattern and extent of dissemination of αSyn pathology does not necessarily follow expected neuroanatomic connectivity. Further, the presence of intra-astrocytic αSyn pathology implies that glial cells participate in αSyn transmission and possibly have a role in non-cell autonomous disease modification.

Topics: alpha-Synuclein; Animals; Brain; Humans; Mice; Mice, Transgenic; Neurodegenerative Diseases

Fluorescence colocalization microscopy is frequently used to assess potential links between distinct molecules; however, this method can lead to striking false-positive results and erroneous conclusions. Here we developed a novel approach with more sophisticated mathematical colocalization analyses together with visualization of physical proximity using fluorescence resonance energy transfer (FRET). To verify our results we used the proximity ligation assay (PLA). With these methods we could demonstrate that distinct neurodegeneration-related proteins either not or only rarely interact in human brain tissue.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Brain; DNA-Binding Proteins; Female; Fluorescence Resonance Energy Transfer; HEK293 Cells; Humans; Image Processing, Computer-Assisted; Male; Microscopy, Fluorescence; Middle Aged; Neurodegenerative Diseases; Proteins; tau Proteins

Proteinaceous inclusions in neurons, composed primarily of α-synuclein, define the pathology in several neurodegenerative disorders. Neurons can internalize α-synuclein fibrils that can seed new inclusions from endogenously expressed α-synuclein. The factors contributing to the spread of pathology and subsequent neurodegeneration are not fully understood, and different compositions and concentrations of fibrils have been used in different hosts. Here, we systematically vary the concentration and length of well-characterized α-synuclein fibrils and determine their relative ability to induce inclusions and neurodegeneration in different hosts (primary neurons, C57BL/6J and C3H/HeJ mice, and Sprague Dawley rats). Using dynamic-light scattering profiles and other measurements to determine fibril length and concentration, we find that femptomolar concentrations of fibrils are sufficient to induce robust inclusions in primary neurons. However, a narrow and non-linear dynamic range characterizes fibril-mediated inclusion induction in axons and the soma. In mice, the C3H/HeJ strain is more sensitive to fibril exposures than C57BL/6J counterparts, with more inclusions and dopaminergic neurodegeneration. In rats, injection of fibrils into the substantia nigra pars compacta (SNpc) results in similar inclusion spread and dopaminergic neurodegeneration as injection of the fibrils into the dorsal striatum, with prominent inclusion spread to the amygdala and several other brain areas. Inclusion spread, particularly from the SNpc to the striatum, positively correlates with dopaminergic neurodegeneration. These results define biophysical characteristics of α-synuclein fibrils that induce inclusions and neurodegeneration both in vitro and in vivo, and suggest that inclusion spread in the brain may be promoted by a loss of neurons.

Topics: Acetylcholinesterase; alpha-Synuclein; Animals; Corpus Striatum; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Humans; Inclusion Bodies; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Neurons; Phosphopyruvate Hydratase; Rats; Rats, Sprague-Dawley; Substantia Nigra; tau Proteins; Tyrosine 3-Monooxygenase

Topics: Acetylcholinesterase; alpha-Synuclein; Amyloid Precursor Protein Secretases; Antioxidants; Cholinesterase Inhibitors; Humans; Neurodegenerative Diseases; Protein Aggregates

Abnormal accumulation of alpha-synuclein (αsyn) is a pathological hallmark of Lewy body related disorders such as Parkinson's disease and Dementia with Lewy body disease. During the past two decades, a myriad of animal models have been developed to mimic pathological features of synucleinopathies by over-expressing human αsyn. Although different strategies have been used, most models have little or no reliable and predictive phenotype. Novel animal models are a valuable tool for understanding neuronal pathology and to facilitate development of new therapeutics for these diseases. Here, we report the development and characterization of a novel model in which mice rapidly express wild-type αsyn via somatic brain transgenesis mediated by adeno-associated virus (AAV). At 1, 3, and 6 months of age following intracerebroventricular (ICV) injection, mice were subjected to a battery of behavioral tests followed by pathological analyses of the brains. Remarkably, significant levels of αsyn expression are detected throughout the brain as early as 1 month old, including olfactory bulb, hippocampus, thalamic regions and midbrain. Immunostaining with a phospho-αsyn (pS129) specific antibody reveals abundant pS129 expression in specific regions. Also, pathologic αsyn is detected using the disease specific antibody 5G4. However, this model did not recapitulate behavioral phenotypes characteristic of rodent models of synucleinopathies. In fact no deficits in motor function or cognition were observed at 3 or 6 months of age. Taken together, these findings show that transduction of neonatal mouse with AAV-αsyn can successfully lead to rapid, whole brain transduction of wild-type human αsyn, but increased levels of wildtype αsyn do not induce behavior changes at an early time point (6 months), despite pathological changes in several neurons populations as early as 1 month.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Astrocytes; Brain; Dependovirus; Disease Models, Animal; Genetic Vectors; Gliosis; HEK293 Cells; Humans; Learning; Memory; Mice, Inbred C57BL; Microglia; Motor Activity; Neurodegenerative Diseases

The accumulation of amyloidogenic proteins is a pathological hallmark of neurodegenerative disorders. The aberrant accumulation of the microtubule associating protein tau (MAPT, tau) into toxic oligomers and amyloid deposits is a primary pathology in tauopathies, the most common of which is Alzheimer's disease (AD). Intrinsically disordered proteins, like tau, are enriched with proline residues that regulate both secondary structure and aggregation propensity. The orientation of proline residues is regulated by cis/trans peptidyl-prolyl isomerases (PPIases). Here we show that cyclophilin 40 (CyP40), a PPIase, dissolves tau amyloids in vitro. Additionally, CyP40 ameliorated silver-positive and oligomeric tau species in a mouse model of tau accumulation, preserving neuronal health and cognition. Nuclear magnetic resonance (NMR) revealed that CyP40 interacts with tau at sites rich in proline residues. CyP40 was also able to interact with and disaggregate other aggregating proteins that contain prolines. Moreover, CyP40 lacking PPIase activity prevented its capacity for disaggregation in vitro. Finally, we describe a unique structural property of CyP40 that may permit disaggregation to occur in an energy-independent manner. This study identifies a novel human protein disaggregase and, for the first time, demonstrates its capacity to dissolve intracellular amyloids.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid; Animals; Blotting, Western; Brain; Cognition Disorders; Cyclophilins; Cyclosporine; Disease Models, Animal; Female; HEK293 Cells; Humans; Male; Mice, Transgenic; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Peptidyl-Prolyl Isomerase F; Protein Aggregates; Protein Aggregation, Pathological; tau Proteins; Tauopathies

The aggregation of the protein ɑ-synuclein (ɑS) underlies a range of increasingly common neurodegenerative disorders including Parkinson's disease. One widely explored therapeutic strategy for these conditions is the use of antibodies to target aggregated ɑS, although a detailed molecular-level mechanism of the action of such species remains elusive. Here, we characterize ɑS aggregation in vitro in the presence of two ɑS-specific single-domain antibodies (nanobodies), NbSyn2 and NbSyn87, which bind to the highly accessible C-terminal region of ɑS.. We show that both nanobodies inhibit the formation of ɑS fibrils. Furthermore, using single-molecule fluorescence techniques, we demonstrate that nanobody binding promotes a rapid conformational conversion from more stable oligomers to less stable oligomers of ɑS, leading to a dramatic reduction in oligomer-induced cellular toxicity.. The results indicate a novel mechanism by which diseases associated with protein aggregation can be inhibited, and suggest that NbSyn2 and NbSyn87 could have significant therapeutic potential.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Protein Binding; Single-Domain Antibodies

The pathology of Parkinson's disease and other synucleinopathies is characterized by the formation of intracellular inclusions comprised primarily of misfolded, fibrillar α-synuclein (α-syn). One strategy to slow disease progression is to prevent the misfolding and aggregation of its native monomeric form. Here we present findings that support the contention that the tricyclic antidepressant compound nortriptyline (NOR) has disease-modifying potential for synucleinopathies. Findings from in vitro aggregation and kinetics assays support the view that NOR inhibits aggregation of α-syn by directly binding to the soluble, monomeric form, and by enhancing reconfiguration of the monomer, inhibits formation of toxic conformations of the protein. We go on to demonstrate that NOR inhibits the accumulation, aggregation and neurotoxicity of α-syn in multiple cell and animal models. These findings suggest that NOR, a compound with established safety and efficacy for treatment of depression, may slow progression of α-syn pathology by directly binding to soluble, native, α-syn, thereby inhibiting pathological aggregation and preserving its normal functions.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antidepressive Agents, Tricyclic; Brain; Cell Line, Tumor; Drosophila; Escherichia coli; Humans; Male; Mice; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Nortriptyline; Protein Aggregation, Pathological; Protein Unfolding; Random Allocation; Rats, Sprague-Dawley; Recombinant Proteins

α-Synuclein is an abundantly expressed neuronal protein that is at the center of focus in understanding a group of neurodegenerative disorders called synucleinopathies, which are characterized by the intracellular presence of aggregated α-synuclein. However, the mechanism of α-synuclein biology in synucleinopathies pathogenesis is not fully understood. In this study, mice overexpressing human A30P*A53T α-synuclein were evaluated by a motor behavior test and count of TH-positive neurons, and then two-dimensional liquid chromatography-tandem mass spectrometry coupled with tandem mass tags (TMTs) labeling was employed to quantitatively identify the differentially expressed proteins of substantia nigra pars compacta (SNpc) tissue samples that were obtained from the α-synuclein transgenic mice and wild type controls. The number of SNpc dopaminergic neurons and the motor behavior were unchanged in A30P*A53T transgenic mice at the age of 6 months. Of the 4,715 proteins identified by proteomic techniques, 271 were differentially expressed, including 249 upregulated and 22 downregulated proteins. These alterations were primarily associated with mitochondrial dysfunction, oxidative stress, ubiquitin-proteasome system impairment, and endoplasmic reticulum (ER) stress. Some obviously changed proteins, which were validated by western blotting and immunofluorescence staining, including Sel1l and Sdhc, may be involved in the α-synuclein pathologies of synucleinopathies. A biological pathway analysis of common related proteins showed that the proteins were linked to a total of 31 KEGG pathways. Our findings suggest that these identified proteins may serve as novel therapeutic targets for synucleinopathies.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Dopaminergic Neurons; Humans; Intracellular Signaling Peptides and Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Proteins; Proteome; Proteomics; Up-Regulation

In neurodegenerative diseases, seeding is a process initiated by the internalization of exogenous protein aggregates. Multiple pathways for internalization of aggregates have been proposed, including direct membrane penetration and endocytosis. To decipher the seeding mechanisms of alpha-synuclein (αS) aggregates in human cells, we visualized αS aggregation, endo-lysosome distribution, and endo-lysosome rupture in real-time. Our data suggest that exogenous αS can seed endogenous cytoplasmic αS by either directly penetrating the plasma membrane or via endocytosis-mediated endo-lysosome rupture, leading to formation of endo-lysosome-free or endo-lysosome-associated αS aggregates, respectively. Further, we demonstrate that αS aggregates isolated from postmortem human brains with diffuse Lewy body disease (DLBD) preferentially show endocytosis-mediated seeding associated with endo-lysosome rupture and have significantly reduced seeding activity compared to recombinant αS aggregates. Colocalization of αS pathology with galectin-3 (a marker of endo-lysosomal membrane rupture) in the basal forebrain of DLBD, but not in age-matched controls, suggests endo-lysosome rupture is involved in the formation of αS pathology in humans. Interestingly, cells with endo-lysosomal membrane permeabilization (LMP) are more vulnerable to the seeding effects of αS aggregates. This study suggests that endo-lysosomal impairment in neurons might play an important role in PD progression.

Topics: alpha-Synuclein; Brain; Endocytosis; Endosomes; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Intracellular Membranes; Lewy Bodies; Lysosomes; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological

We have previously demonstrated that anti-beta amyloid DNA vaccine (AV-1959D) based on our proprietary MultiTEP platform technology is extremely immunogenic in mice, rabbits, and monkeys. Importantly, MultiTEP platform enables development of vaccines targeting pathological molecules involved in various neurodegenerative disorders. Taking advantage of the universality of MultiTEP platform, we developed DNA vaccines targeting 3 B-cell epitopes (amino acids [aa]85-99, aa109-126, and aa126-140) of human alpha-synuclein (hα-Syn) separately or all 3 epitopes simultaneously. All 4 DNA vaccines (1) generate high titers of anti-hα-Syn antibodies and (2) induce robust MultiTEP-specific T-helper cell responses without activation of potentially detrimental autoreactive anti-hα-Syn T-helper cells. Generated antibodies recognize misfolded hα-Syn produced by neuroblastoma cells, hα-Syn in the brain tissues of transgenic mouse strains and in the brain tissues of dementia with Lewy body cases. Based on these results, the most promising vaccine targeting 3 B-cell epitopes of hα-Syn simultaneously (PV-1950D) has been chosen for ongoing preclinical assessment in mouse models of hα-Syn with the aim to translate it to the human clinical trials.

Topics: alpha-Synuclein; Animals; Antibodies; Epitopes, B-Lymphocyte; Female; Humans; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; T-Lymphocytes, Helper-Inducer; Vaccines, DNA

α-Synuclein (aSyn) is the main driver of neurodegenerative diseases known as "synucleinopathies," but the mechanisms underlying this toxicity remain poorly understood. To investigate aSyn toxic mechanisms, we have developed a primary neuronal model in which a longitudinal survival analysis can be performed by following the overexpression of fluorescently tagged WT or pathologically mutant aSyn constructs. Most aSyn mutations linked to neurodegenerative disease hindered neuronal survival in this model; of these mutations, the E46K mutation proved to be the most toxic. While E46K induced robust PLK2-dependent aSyn phosphorylation at serine 129, inhibiting this phosphorylation did not alleviate aSyn toxicity, strongly suggesting that this pathological hallmark of synucleinopathies is an epiphenomenon. Optical pulse-chase experiments with Dendra2-tagged aSyn versions indicated that the E46K mutation does not alter aSyn protein turnover. Moreover, since the mutation did not promote overt aSyn aggregation, we conclude that E46K toxicity was driven by soluble species. Finally, we developed an assay to assess whether neurons expressing E46K aSyn affect the survival of neighboring control neurons. Although we identified a minor non-cell-autonomous component spatially restricted to proximal neurons, most E46K aSyn toxicity was cell autonomous. Thus, we have been able to recapitulate the toxicity of soluble aSyn species at a stage preceding aggregation, detecting non-cell-autonomous toxicity and evaluating how some of the main aSyn hallmarks are related to neuronal survival.

Topics: alpha-Synuclein; Amino Acid Substitution; Animals; Mutation, Missense; Neurodegenerative Diseases; Neurons; Phosphorylation; Protein Aggregation, Pathological; Rats; Rats, Sprague-Dawley

Alpha synuclein (α-syn) is a central player in neurodegeneration, but the mechanisms triggering its pathology are not fully understood. Here we found that α-syn is a highly efficient substrate for arginyltransferase ATE1 and is arginylated in vivo by a novel mid-chain mechanism that targets the acidic side chains of E46 and E83. Lack of arginylation leads to increased α-syn aggregation and causes the formation of larger pathological aggregates in neurons, accompanied by impairments in its ability to be cleared via normal degradation pathways. In the mouse brain, lack of arginylation leads to an increase in α-syn's insoluble fraction, accompanied by behavioral changes characteristic for neurodegenerative pathology. Our data show that lack of arginylation in the brain leads to neurodegeneration, and suggests that α-syn arginylation can be a previously unknown factor that facilitates normal α-syn folding and function in vivo.

Topics: alpha-Synuclein; Amino Acid Sequence; Aminoacyltransferases; Animals; Arginine; Brain; Cells, Cultured; Disease Models, Animal; Humans; Mass Spectrometry; Mice; Mice, Knockout; Models, Biological; Neurodegenerative Diseases; Neurons; Peptides; Protein Aggregates; Protein Aggregation, Pathological; Protein Processing, Post-Translational; Proteolysis; Recombinant Proteins; Substrate Specificity

Parkinson's disease (PD) is defined by the loss of dopaminergic neurons in the substantia nigra and the formation of Lewy body inclusions containing aggregated α-synuclein. Efforts to explain dopamine neuron vulnerability are hindered by the lack of dopaminergic cell death in α-synuclein transgenic mice. To address this, we manipulated both dopamine levels and α-synuclein expression. Nigrally targeted expression of mutant tyrosine hydroxylase with enhanced catalytic activity increased dopamine levels without damaging neurons in non-transgenic mice. In contrast, raising dopamine levels in mice expressing human A53T mutant α-synuclein induced progressive nigrostriatal degeneration and reduced locomotion. Dopamine elevation in A53T mice increased levels of potentially toxic α-synuclein oligomers, resulting in conformationally and functionally modified species. Moreover, in genetically tractable Caenorhabditis elegans models, expression of α-synuclein mutated at the site of interaction with dopamine prevented dopamine-induced toxicity. These data suggest that a unique mechanism links two cardinal features of PD: dopaminergic cell death and α-synuclein aggregation.

Topics: alpha-Synuclein; Animals; Caenorhabditis elegans; Cells, Cultured; Corpus Striatum; Dopamine; Dopaminergic Neurons; Female; Humans; Levodopa; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Substantia Nigra

Recent studies have demonstrated that dysregulation of macroautophagy/autophagy may play a central role in the pathogenesis of neurodegenerative disorders, and the induction of autophagy protects against the toxic insults of aggregate-prone proteins by enhancing their clearance. Thus, autophagy has become a promising therapeutic target against neurodegenerative diseases. In this study, quantitative phosphoproteomic profiling together with a computational analysis was performed to delineate the phosphorylation signaling networks regulated by 2 natural neuroprotective autophagy enhancers, corynoxine (Cory) and corynoxine B (Cory B). To identify key regulators, namely, protein kinases, we developed a novel network-based algorithm of in silico Kinome Activity Profiling (iKAP) to computationally infer potentially important protein kinases from phosphorylation networks. Using this algorithm, we observed that Cory or Cory B potentially regulated several kinases. We predicted and validated that Cory, but not Cory B, downregulated a well-documented autophagy kinase, RPS6KB1/p70S6K (ribosomal protein S6 kinase, polypeptide 1). We also discovered 2 kinases, MAP2K2/MEK2 (mitogen-activated protein kinase kinase 2) and PLK1 (polo-like kinase 1), to be potentially upregulated by Cory, whereas the siRNA-mediated knockdown of Map2k2 and Plk1 significantly inhibited Cory-induced autophagy. Furthermore, Cory promoted the clearance of Alzheimer disease-associated APP (amyloid β [A4] precursor protein) and Parkinson disease-associated SNCA/α-synuclein (synuclein, α) by enhancing autophagy, and these effects were dramatically diminished by the inhibition of the kinase activities of MAP2K2 and PLK1. As a whole, our study not only developed a powerful method for the identification of important regulators from the phosphoproteomic data but also identified the important role of MAP2K2 and PLK1 in neuronal autophagy.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Autophagy; Cell Cycle Proteins; Computer Simulation; Indoles; MAP Kinase Kinase 2; Mice; Neurodegenerative Diseases; Neurons; PC12 Cells; Phosphoproteins; Phosphorylation; Polo-Like Kinase 1; Protein Serine-Threonine Kinases; Proteome; Proto-Oncogene Proteins; Rats; Ribosomal Protein S6 Kinases, 70-kDa; Spiro Compounds

Cerebral malaria, a reversible encephalopathy affecting young children, is a medical emergency requiring urgent clinical assessment and treatment. We performed a whole-transcriptomic analysis of blood samples from Malian children with cerebral or uncomplicated malaria. We focused on transcripts from pathways for which dysfunction has been associated with neurodegenerative disorders. We found that SNCA, SIAH2, UBB, HSPA1A, TUBB2A, and PINK1 were upregulated (fold-increases, ≥2.6), whereas UBD and PSMC5 were downregulated (fold-decreases, ≤4.39) in children with cerebral malaria, compared with those with uncomplicated malaria. These findings provide the first evidence for pathogenic mechanisms common to human cerebral malaria and neurodegenerative disorders.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; ATPases Associated with Diverse Cellular Activities; Child; Child, Preschool; Down-Regulation; Female; Gene Expression Profiling; HSP70 Heat-Shock Proteins; Humans; Leukocytes, Mononuclear; LIM Domain Proteins; Malaria, Cerebral; Malaria, Falciparum; Male; Neurodegenerative Diseases; Nuclear Proteins; Plasmodium falciparum; Prospective Studies; Proteasome Endopeptidase Complex; Protein Kinases; Reproducibility of Results; Transcription Factors; Tubulin; Ubiquitin; Ubiquitin-Protein Ligases; Ubiquitins; Up-Regulation

The synuclein family has long been associated with Parkinson's disease and dementia. Although the self-assembly of α-synuclein (αS) into oligomers and amyloid fibrils is well established, the aggregation propensity of other members of the family and their role in disease is still under debate. Moriarty

Topics: alpha-Synuclein; Amyloid; beta-Synuclein; Humans; Neurodegenerative Diseases; Parkinson Disease

Neurofilaments are a major component of the axonal cytoskeleton in neurons and have been implicated in a number of neurodegenerative diseases due to their presence within characteristic pathological inclusions. Their contributions to these diseases are not yet fully understood, but previous studies investigated the effects of ablating the obligate subunit of neurofilaments, low molecular mass neurofilament subunit (NFL), on disease phenotypes in transgenic mouse models of Alzheimer's disease and tauopathy. Here, we tested the effects of ablating NFL in α-synuclein M83 transgenic mice expressing the human pathogenic A53T mutation, by breeding them onto an NFL null background. The induction and spread of α-synuclein inclusion pathology was triggered by the injection of preformed α-synuclein fibrils into the gastrocnemius muscle or hippocampus in M83 versus M83/NFL null mice. We observed no difference in the post-injection time to motor-impairment and paralysis endpoint or amount and distribution of α-synuclein inclusion pathology in the muscle injected M83 and M83/NFL null mice. Hippocampal injected M83/NFL null mice displayed subtle region-specific differences in the amount of α-synuclein inclusions however, pathology was observed in the same regions as the M83 mice. Overall, we observed only minor differences in the induction and transmission of α-synuclein pathology in these induced models of synucleinopathy in the presence or absence of NFL. This suggests that NFL and neurofilaments do not play a major role in influencing the induction and transmission of α-synuclein aggregation.

Topics: alpha-Synuclein; Animals; Brain; Inclusion Bodies; Intermediate Filaments; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Prions

Neurodegenerative diseases are disorders characterized by progressive loss of neurons associated with deposition of proteins showing altered physicochemical properties in the brain and in peripheral organs. Molecular classification of neurodegenerative disease is protein-based. This emphasizes the role of protein-processing systems in the pathogenesis. The most frequent proteins involved in the pathogenesis of neurodegenerative diseases are amyloid-β, prion protein, tau, α-synuclein, TAR-DNA-binding protein 43kDa, and fused-in sarcoma protein. There are further proteins associated mostly with hereditary disorders such as proteins encoded by genes linked to trinucleotide repeat disorders, neuroserpin, ferritin, and familial cerebral amyloidoses. The clinical presentations are defined by the distinct involvement of functional systems and do not necessarily indicate the molecular pathologic background. Seeding of pathologic proteins and hierarchic involvement of anatomic regions is commonly seen in neurodegenerative diseases. Overlap of neurodegenerative diseases and combinations of different disorders is frequent. Translation of neuropathologic categories of neurodegenerative diseases into in vivo detectable biomarkers is only partly achieved but intensive research is performed to reach this goal.

Topics: alpha-Synuclein; Animals; Biomarkers; Brain; Cognition Disorders; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Pathology, Molecular; Prion Proteins; RNA-Binding Protein FUS; tau Proteins

Parkinson's disease (PD) is one of many neurodegenerative diseases termed synucleinopathies, neuropathologically defined by inclusions containing aggregated α-synuclein (αS). αS gene (SNCA) mutations can directly cause autosomal dominant PD. In vitro studies demonstrated that SNCA missense mutations may either enhance or diminish αS aggregation but cross-seeding of mutant and wild-type αS proteins appear to reduce aggregation efficiency. Here, we extended these studies by assessing the effects of seeded αS aggregation in αS transgenic mice through intracerebral or peripheral injection of various mutant αS fibrils. We observed modestly decreased time to paralysis in mice transgenic for human A53T αS (line M83) intramuscularly injected with H50Q, G51D or A53E αS fibrils relative to wild-type αS fibrils. Conversely, E46K αS fibril seeding was significantly delayed and less efficient in the same experimental paradigm. However, the amount and distribution of αS inclusions in the central nervous system were similar for all αS fibril muscle injected mice that developed paralysis. Mice transgenic for human αS (line M20) injected in the hippocampus with wild-type, H50Q, G51D or A53E αS fibrils displayed induction of αS inclusion pathology that increased and spread over time. By comparison, induction of αS aggregation following the intrahippocampal injection of E46K αS fibrils in M20 mice was much less efficient. These findings show that H50Q, G51D or A53E can efficiently cross-seed and induce αS pathology in vivo. In contrast, E46K αS fibrils are intrinsically inefficient at seeding αS inclusion pathology. Consistent with previous in vitro studies, E46K αS polymers are likely distinct aggregated conformers that may represent a unique prion-like strain of αS.

Topics: alpha-Synuclein; Animals; Central Nervous System; Gene Expression; Gene Expression Regulation; Humans; Inclusion Bodies; Mice; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is a neurodegenerative disease that is associated with aging and is characterized as a movement disorder. Currently, there is still no complete therapy for PD. In recent years, the identification and characterization of medicinal plants to cure or treat PD has gained increasing scientific interest.. In this study, we investigated a pentacyclic triterpenoid compound, β-amyrin, which is found in many medicinal plants for its anti-Parkinsonian effects, using Caenorhabditis elegans (C. elegans) disease models and their underlying mechanisms.. C. elegans treated or untreated with β-amyrin were investigated for oxidative stress resistance, neurodegeneration, and α-synuclein aggregation assays. The C. elegans ortholog of Atg8/LC3, LGG-1 that is involved in the autophagy pathway was also evaluated by quantitative RT-PCR and transgenic strain experiments.. β-Amyrin exerted excellent antioxidant activity and reduced intracellular oxygen species in C. elegans. Using the transgenic strain BZ555, β-amyrin showed a protective effect on dopaminergic neurons reducing cell damage induced by 6-hydroxydopamine (6-OHDA). In addition, β-amyrin significantly reduced the α-synuclein aggregation in the transgenic strain NL5901. Moreover, β-amyrin up-regulated LGG-1 mRNA expression and increased the number of localized LGG-1 puncta in the transgenic strain DA2123.. The results from this study suggest that the anti-Parkinsonian effects of β-amyrin might be regulated via LGG-1 involved autophagy pathway in C. elegans. Therefore, β-amyrin may be useful for therapeutic applications or supplements to treat or slow the progression of PD.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Antioxidants; Antiparkinson Agents; Autophagy; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Dopaminergic Neurons; Microtubule-Associated Proteins; Neurodegenerative Diseases; Oleanolic Acid; Oxidative Stress; Parkinson Disease

Alpha-synuclein (α-SYN) is a central molecule in Parkinson's disease pathogenesis. Despite several studies, the molecular nature of endogenous α-SYN especially in human brain samples is still not well understood due to the lack of reliable methods and the limited amount of biospecimens. Here, we introduce α-SYN single-molecule pull-down (α-SYN SiMPull) assay combined with in vivo protein crosslinking to count individual α-SYN protein and assess its native oligomerization states from biological samples including human postmortem brains. This powerful single-molecule assay can be highly useful in diagnostic applications using various specimens for neurodegenerative diseases including Alzheimer's disease and Parkinson's disease.

Topics: alpha-Synuclein; Brain; Cells, Cultured; HEK293 Cells; Humans; Neurodegenerative Diseases

A cascade of pathological changes in the intact hemisphere developed in rats 6 months after focal unilateral traumatic brain injury: neuronal degeneration, hyperexpression of α-synuclein, APP (β-amyloid peptide precursor) protein, and glutamine synthetase in cells other than astrocytes. The development of these changes in the contralateral hemisphere indicated the emergence of extensive delayed neurodegenerative processes in the brain after traumatic brain injury, which were characteristic of diseases associated with pathological aging.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Astrocytes; Brain Injuries, Traumatic; Cerebrum; Delayed Diagnosis; Gene Expression; Glutamate-Ammonia Ligase; Male; Neurodegenerative Diseases; Rats; Rats, Wistar; Time Factors; Up-Regulation

Parkinson's disease (PD) is an aging-associated neurodegenerative disease with a characteristic feature of α-synuclein accumulation. Point mutations (A53T, A30P) that increase the aggregation propensity of α-synuclein result in familial early onset PD. The abnormal metabolism of α-synuclein results in aberrant level changes of α-synuclein in PD. In pathological conditions, α-synuclein is degraded mainly by the autophagy-lysosome pathway. Triptolide (T10) is a monomeric compound isolated from a traditional Chinese herb. Our group demonstrated for the first time that T10 possesses potent neuroprotective properties both in vitro and in vivo PD models. In the present study, we reported T10 as a potent autophagy inducer in neuronal cells, which helped to promote the clearance of various forms of α-synuclein in neuronal cells. We transfected neuronal cells with A53T mutant (A53T) or wild-type (WT) α-synuclein plasmids and found T10 attenuated the cytotoxicity induced by pathogenic A53T α-synuclein overexpression. We observed that T10 significantly reduced both A53T and WT α-synuclein level in neuronal cell line, as well as in primary cultured cortical neurons. Excluding the changes of syntheses, secretion, and aggregation of α-synuclein, we further added autophagy inhibitor or proteasome inhibitor with T10, and we noticed that T10 promoted the clearance of α-synuclein mainly by the autophagic pathway. Lastly, we observed increased autophagy marker LC3-II expression and autophagosomes by GFP-LC3-II accumulation and ultrastructural characterization. However, the lysosome activity and cell viability were not modulated by T10. Our study revealed that T10 could induce autophagy and promote the clearance of both WT and A53T α-synuclein in neurons. These results provide evidence of T10 as a promising mean to treat PD and other neurodegenerative diseases by reducing pathogenic proteins in neurons.

Topics: alpha-Synuclein; Animals; Autophagy; Cell Line; Cell Survival; Diterpenes; Epoxy Compounds; Female; Lysosomes; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Phenanthrenes

Pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD) and Huntington's disease (HD) are closely related to the formation of protein aggregates and inclusion body. For instance, active autophagic components from Chinese herbal medicines (CHMs) are highlighted to modulate neurodegeneration via degradation of disease proteins. In this study, the neuroprotective effect of the purified Hedera helix (HH) fraction containing both hederagenin and α-hederin, is confirmed by the improvement of motor deficits in PD mice model. Furthermore, hederagenin and α-hederin derived from HH are confirmed as novel autophagic enhancers. Both compounds reduce the protein level of mutant huntingtin with 74 CAG repeats and A53T α-synuclein, and inhibit the oligomerization of α-synuclein and inclusion formation of huntingtin, via AMPK-mTOR dependent autophagy induction. Both hederagenin and α-hederin induce autophagy and promote the degradation of neurodegenerative mutant disease proteins in vitro, suggesting the therapeutic roles of HH in neurodegenerative disorders.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Adenylate Kinase; alpha-Synuclein; Animals; Autophagy; Cell Line, Tumor; Disease Models, Animal; Drugs, Chinese Herbal; Female; Hedera; Huntingtin Protein; Male; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Oleanolic Acid; PC12 Cells; Rats; Saponins; TOR Serine-Threonine Kinases

Misfolded α-synuclein (αS) is hypothesized to spread throughout the central nervous system (CNS) by neuronal connectivity leading to widespread pathology. Increasing evidence indicates that it also has the potential to invade the CNS via peripheral nerves in a prion-like manner. On the basis of the effectiveness following peripheral routes of prion administration, we extend our previous studies of CNS neuroinvasion in M83 αS transgenic mice following hind limb muscle (intramuscular [i.m.]) injection of αS fibrils by comparing various peripheral sites of inoculations with different αS protein preparations. Following intravenous injection in the tail veins of homozygous M83 transgenic (M83. The misfolding and accumulation of α-synuclein (αS) inclusions are found in a number of neurodegenerative disorders and is a hallmark feature of Parkinson's disease (PD) and PD-related diseases. Similar characteristics have been observed between the infectious prion protein and αS, including its ability to spread from the peripheral nervous system and along neuroanatomical tracts within the central nervous system. In this study, we extend our previous results and investigate the efficiency of intravenous (i.v.), intraperitoneal (i.p.), and intramuscular (i.m.) routes of injection of αS fibrils and other protein controls. Our data reveal that injection of αS fibrils via these peripheral routes in αS-overexpressing mice are capable of inducing a robust αS pathology and in some cases cause paralysis. Furthermore, soluble, nonaggregated αS also induced αS pathology, albeit with much less efficiency. These findings further support and extend the idea of αS neuroinvasion from peripheral exposures.

Topics: alpha-Synuclein; Animals; Brain; Central Nervous System Diseases; Disease Models, Animal; Inclusion Bodies; Mice; Mice, Transgenic; Neurodegenerative Diseases; Phenotype; Protein Aggregates; Protein Aggregation, Pathological; Spinal Cord

Lysosomal storage disorders (LSDs) are inherited diseases characterized by lysosomal dysfunction and often showing a neurodegenerative course. There is no cure to treat the central nervous system in LSDs. Moreover, the mechanisms driving neuronal degeneration in these pathological conditions remain largely unknown. By studying mouse models of LSDs, we found that neurodegeneration develops progressively with profound alterations in presynaptic structure and function. In these models, impaired lysosomal activity causes massive perikaryal accumulation of insoluble α-synuclein and increased proteasomal degradation of cysteine string protein α (CSPα). As a result, the availability of both α-synuclein and CSPα at nerve terminals strongly decreases, thus inhibiting soluble NSF attachment receptor (SNARE) complex assembly and synaptic vesicle recycling. Aberrant presynaptic SNARE phenotype is recapitulated in mice with genetic ablation of one allele of both CSPα and α-synuclein. The overexpression of CSPα in the brain of a mouse model of mucopolysaccharidosis type IIIA, a severe form of LSD, efficiently re-established SNARE complex assembly, thereby ameliorating presynaptic function, attenuating neurodegenerative signs, and prolonging survival. Our data show that neurodegenerative processes associated with lysosomal dysfunction may be presynaptically initiated by a concomitant reduction in α-synuclein and CSPα levels at nerve terminals. They also demonstrate that neurodegeneration in LSDs can be slowed down by re-establishing presynaptic functions, thus identifying synapse maintenance as a novel potentially druggable target for brain treatment in LSDs.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; HSP40 Heat-Shock Proteins; Lysosomal Storage Diseases; Membrane Proteins; Mice; Neurodegenerative Diseases; Presynaptic Terminals; Proteolysis; SNARE Proteins; Synaptic Vesicles

A signature feature of age-related neurodegenerative proteinopathies is the misfolding and aggregation of proteins, typically amyloid-β (Aβ) in Alzheimer's disease (AD) and α-synuclein (α-syn) in Parkinson's disease (PD), into soluble oligomeric structures that are highly neurotoxic. Cellular and animal models that faithfully replicate the hallmark features of these disorders are being increasing exploited to identify disease-modifying compounds. Natural compounds have been identified as a useful source of bioactive molecules with promising neuroprotective capabilities. In the present report, we investigated whether extracts derived from two ubiquitous Mediterranean plants namely, the prickly pear Opuntia ficus-indica (EOFI) and the brown alga Padina pavonica (EPP) alleviate neurodegenerative phenotypes in yeast (Saccharomyces cerevisiae) and fly (Drosophila melanogaster) models of AD and PD. Pre-treatment with EPP or EOFI in the culture medium significantly improved the viability of yeast expressing the Arctic Aβ42 (E22G) mutant. Supplementing food with EOFI or EPP dramatically ameliorated lifespan and behavioural signs of flies with brain-specific expression of wild-type Aβ42 (model of late-onset AD) or the Arctic Aβ42 variant (model of early-onset AD). Additionally, we show that either extract prolonged the survival of a PD fly model based on transgenic expression of the human α-syn A53T mutant. Taken together, our findings suggest that the plant-derived extracts interfere with shared mechanisms of neurodegeneration in AD and PD. This notion is strengthened by evidence demonstrating that EOFI and to a greater extent EPP, while strongly inhibiting the fibrillogenesis of both Aβ42 and α-syn, accumulate remodelled oligomeric aggregates that are less effective at disrupting lipid membrane integrity. Our work therefore opens new avenues for developing therapeutic applications of these natural plant extracts in the treatment of amyloidogenic neurodegenerative disorders.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Drosophila melanogaster; Humans; Mutation; Neurodegenerative Diseases; Neuroprotective Agents; Opuntia; Parkinson Disease; Peptide Fragments; Phaeophyceae; Plant Extracts; Saccharomyces cerevisiae

Protein misfolding and aggregation are key pathological features of many neurodegenerative diseases including Parkinson's disease (PD) and other forms of human Parkinsonism. PD is a complex and multifaceted disorder whose etiology is not fully understood. However, several lines of evidence support the multiple hit hypothesis that genetic vulnerability and environmental toxicants converge to trigger PD pathology. Alpha-synuclein (α-Syn) aggregation in the brain is an important pathophysiological characteristic of synucleinopathies including PD. Epidemiological and experimental studies have shown that metals and pesticides play a crucial role in α-Syn aggregation leading to the onset of various neurodegenerative diseases including PD. In this review, we will emphasize key findings of several epidemiological as well as experimental studies of metal- and pesticide-induced α-Syn aggregation and neurodegeneration. We will also discuss other factors such as traumatic brain injury and oxidative insult in the context of α-Syn-related neurodegenerative processes.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Brain; Brain Injuries, Traumatic; Humans; Neurodegenerative Diseases; Oxidative Stress; Parkinson Disease; Pesticides; Protein Aggregates; Proteostasis Deficiencies

Cell-to-cell transmission of α-synuclein (αSyn) is hypothesized to play an important role in disease progression in synucleinopathies. This process involves cellular uptake of extracellular amyloidogenic αSyn seeds followed by seeding of endogenous αSyn. Though it is well known that αSyn is an immunogenic protein that can interact with immune receptors, the role of innate immunity in regulating induction of αSyn pathology in vivo is unknown. Herein, we explored whether altering innate immune activation affects induction of αSyn pathology in wild type mice.. We have previously demonstrated that recombinant adeno-associated virus (AAV) mediated expression of the inflammatory cytokine, Interleukin (IL)-6, in neonatal wild type mice brains leads to widespread immune activation in the brain without overt neurodegeneration. To investigate how IL-6 expression affects induction of αSyn pathology, we injected mouse wild type αSyn fibrils in the hippocampus of AAV-IL-6 expressing mice. Control mice received AAV containing an Empty vector (EV) construct. Two separate cohorts of AAV-IL-6 and AAV-EV mice were analyzed in this study: 4 months or 2 months following intrahippocampal αSyn seeding.. Here, we show that IL-6 expression resulted in widespread gliosis and concurrently reduced αSyn inclusion pathology induced by a single intra-hippocampal injection of exogenous amyloidogenic αSyn. The reduction in αSyn inclusion pathology in IL-6 expressing mice was time-dependent. Suppression of αSyn pathology was accompanied by reductions in both argyrophilic and p62 immunoreactive inclusions.. Our data supports a beneficial role of inflammatory priming of the CNS in wild type mice challenged with exogenous αSyn. A likely mechanism is efficient astroglial scavenging of exogenous αSyn, at least early in the disease process, and in the absence of human αSyn transgene overexpression. Given evidence that a pro-inflammatory environment may restrict seeding of αSyn pathology, this can be used to design anti-αSyn immunobiotherapies by harnessing innate immune function.

Topics: alpha-Synuclein; Animals; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Gliosis; Hippocampus; Immunohistochemistry; Inflammation; Interleukin-6; Mice; Mice, Transgenic; Neurodegenerative Diseases

Neurodegenerative disorders such as Parkinson's Disease (PD), PD dementia (PDD) and Dementia with Lewy bodies (DLB) are characterized by progressive accumulation of α-synuclein (α-syn) in neurons. Recent studies have proposed that neuron-to-neuron propagation of α-syn plays a role in the pathogenesis of these disorders. We have previously shown that antibodies against the C-terminus of α-syn reduce the intra-neuronal accumulation of α-syn and related deficits in transgenic models of synucleinopathy, probably by abrogating the axonal transport and accumulation of α-syn in in vivo models. Here, we assessed the effect of passive immunization against α-syn in a new mouse model of axonal transport and accumulation of α-syn. For these purpose, non-transgenic, α-syn knock-out and mThy1-α-syn tg (line 61) mice received unilateral intra-cerebral injections with a lentiviral (LV)-α-syn vector construct followed by systemic administration of the monoclonal antibody 1H7 (recognizes amino acids 91-99) or control IgG for 3 months. Cerebral α-syn accumulation and axonopathy was assessed by immunohistochemistry and effects on behavior were assessed by Morris water maze. Unilateral LV-α-syn injection resulted in axonal propagation of α-syn in the contra-lateral site with subsequent behavioral deficits and axonal degeneration. Passive immunization with 1H7 antibody reduced the axonal accumulation of α-syn in the contra-lateral side and ameliorated the behavioral deficits. Together this study supports the notion that immunotherapy might improve the deficits in models of synucleinopathy by reducing the axonal propagation and accumulation of α-syn. This represents a potential new mode of action through which α-syn immunization might work.

Topics: alpha-Synuclein; Animals; Antibodies, Monoclonal; Axonal Transport; Axons; Brain; Disease Models, Animal; Female; Functional Laterality; Genetic Vectors; Humans; Immunization, Passive; Lentivirus; Maze Learning; Mice, Transgenic; Neurodegenerative Diseases

Numerous genes and molecular pathways are implicated in neurodegenerative proteinopathies, but their inter-relationships are poorly understood. We systematically mapped molecular pathways underlying the toxicity of alpha-synuclein (α-syn), a protein central to Parkinson's disease. Genome-wide screens in yeast identified 332 genes that impact α-syn toxicity. To "humanize" this molecular network, we developed a computational method, TransposeNet. This integrates a Steiner prize-collecting approach with homology assignment through sequence, structure, and interaction topology. TransposeNet linked α-syn to multiple parkinsonism genes and druggable targets through perturbed protein trafficking and ER quality control as well as mRNA metabolism and translation. A calcium signaling hub linked these processes to perturbed mitochondrial quality control and function, metal ion transport, transcriptional regulation, and signal transduction. Parkinsonism gene interaction profiles spatially opposed in the network (ATP13A2/PARK9 and VPS35/PARK17) were highly distinct, and network relationships for specific genes (LRRK2/PARK8, ATXN2, and EIF4G1/PARK18) were confirmed in patient induced pluripotent stem cell (iPSC)-derived neurons. This cross-species platform connected diverse neurodegenerative genes to proteinopathy through specific mechanisms and may facilitate patient stratification for targeted therapy.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Ataxin-2; Disease Susceptibility; DNA-Binding Proteins; Endoplasmic Reticulum; Eukaryotic Initiation Factor-4G; Gene Regulatory Networks; Genome, Fungal; Humans; Induced Pluripotent Stem Cells; Neurodegenerative Diseases; Neurons; Saccharomyces cerevisiae

Parkinson's disease (PD) is a common neurodegenerative disorder that exhibits motor and non-motor symptoms, as well as pathological hallmarks, including dopaminergic (DA) neuron death and formation of α-synuclein (α-Syn) Lewy bodies. Cyclin-G-associated kinase (GAK), a PD susceptibility gene identified through genome-wide association studies (GWAS), is a ubiquitous serine/threonine kinase involved in clathrin uncoating, though its PD-related function remains elusive. Here, we implicate the Drosophila GAK homolog, auxilin (aux), in a broad spectrum of parkinsonian-like symptoms. Downregulating aux expression leads to progressive loss of climbing ability, decreased lifespan, and age-dependent DA neuron death similar to α-Syn overexpression. Reduced aux expression further enhances and accelerates α-Syn-mediated DA neuron loss. Flies with reduced aux expression are more sensitive to the toxin paraquat, suggesting that genetic and environmental factors intertwine. Taken together, these findings decipher a pivotal role for GAK/aux and suggest mechanisms underlying PD.

Topics: alpha-Synuclein; Animals; Auxilins; Clathrin; Dopamine; Dopaminergic Neurons; Down-Regulation; Drosophila; Genome-Wide Association Study; Lewy Bodies; Locomotion; Neurodegenerative Diseases; Parkinson Disease; Protein Serine-Threonine Kinases

Synucleinophaties are progressive neurodegenerative disorders with no cure to date. An attractive strategy to tackle this problem is repurposing already tested safe drugs against novel targets. In this way, doxycycline prevents neurodegeneration in Parkinson models by modulating neuroinflammation. However, anti-inflammatory therapy per se is insufficient to account for neuroprotection. Herein we characterise novel targets of doxycycline describing the structural background supporting its effectiveness as a neuroprotector at subantibiotic doses. Our results show that doxycycline reshapes α-synuclein oligomers into off-pathway, high-molecular-weight species that do not evolve into fibrils. Off-pathway species present less hydrophobic surface than on-pathway oligomers and display different β-sheet structural arrangement. These structural changes affect the α-synuclein ability to destabilize biological membranes, cell viability, and formation of additional toxic species. Altogether, these mechanisms could act synergically giving novel targets for repurposing this drug.

Topics: alpha-Synuclein; Cell Line, Tumor; Cell Survival; Doxycycline; Drug Repositioning; Humans; Magnetic Resonance Spectroscopy; Models, Molecular; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; Protein Binding; Protein Conformation, beta-Strand; Protein Multimerization; Spectroscopy, Fourier Transform Infrared

Network neighbors improve yeast to human gene mapping for the study of parkinsonism.

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases

Parkinson's disease and dementia with Lewy bodies are major challenges in research and clinical medicine world-wide and contribute to the most common neurodegenerative disorders. Previously, specific mitochondrial polymorphisms have been found to enhance clearance of amyloid-β from the brain of APP-transgenic mice leading to beneficial clinical outcome. It has been discussed whether specific mitochondrial alterations contribute to disease progression or even prevent toxic peptide deposition, as seen in many neurodegenerative diseases. Here, we investigated α-synuclein-transgenic C57BL/6J mice with the A30P mutation, and a novel A30P C57BL/6J mouse model with three mitochondrial DNA polymorphisms in the ND3, COX3 and mtRNA(Arg) genes, as found in the inbred NOD/LtJ mouse strain. We were able to detect that the new model has increased mitochondrial complex II-respiration which occurs in parallel to neuronal loss and improved motor performance, although it exhibits higher amounts of high molecular weight species of α-synuclein. High molecular weight aggregates of different peptides are controversially discussed in the light of neurodegeneration. A favourable hypothesis states that high molecular weight species are protective and of minor importance for the pathogenesis of neurodegenerative disorders as compared to the extreme neurotoxic monomers and oligomers. Summarising, our results point to a potentially protective and beneficial effect of specific mitochondrial polymorphisms which cause improved mitochondrial complex II-respiration in α-synucleinopathies, an effect that could be exploited further for pharmaceutical interventions.

Topics: alpha-Synuclein; Animals; Cell Respiration; Electron Transport Complex II; Female; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Transgenic; Mitochondria; Neurodegenerative Diseases

Posttranslational modifications (PTMs) serve as molecular switches for regulating protein folding, function, and interactome and have been implicated in the misfolding and amyloid formation by several proteins linked to neurodegenerative diseases, including Alzheimer's and Parkinson's disease. Understanding the role of individual PTMs in protein misfolding and aggregation requires the preparation of site-specifically modified proteins, as well as the identification of the enzymes involved in regulating these PTMs. Recently, our group has pioneered the development of enzymatic, synthetic, and semisynthetic strategies that allow site-specific introduction of PTMs at single or multiple sites and generation of modified proteins in milligram quantities. In this chapter, we provide detailed description of enzymatic and semisynthetic strategies for the generation of the phosphorylated α-Synuclein (α-Syn) at S129, (pS129), which has been identified as a pathological hallmark of Parkinson's disease. The semisynthetic method described for generation of α-Syn-pS129 requires expertise with protein chemical ligation, but can be used to incorporate other PTMs (single or multiple) within the α-Syn C-terminus if desired. On the other hand, the in vitro kinase-mediated phosphorylation strategy does not require any special setup and is rather easy to apply, but its application is restricted to the generation of α-Syn_pS129. These methods have the potential to increase the availability of pure and homogenous modified α-Syn reagents, which may be used as standards in numerous applications, including the search for potential biomarkers of synucleinopathies.

Topics: alpha-Synuclein; Biomarkers; Humans; Molecular Biology; Neurodegenerative Diseases; Phosphorylation; Protein Folding; Protein Processing, Post-Translational

Topics: alpha-Synuclein; Alzheimer Disease; Amyotrophic Lateral Sclerosis; Brain; C9orf72 Protein; Chronic Pain; Epilepsy; Genome-Wide Association Study; Humans; Mental Disorders; Neuralgia; Neurobiology; Neurodegenerative Diseases; Parkinson Disease; Proteins; tau Proteins; Tauopathies

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases

Topics: alpha-Synuclein; Animals; Immunologic Factors; Interferon-beta; Mice; Neurodegenerative Diseases

Topics: alpha-Synuclein; Animals; Humans; Mice; Neurodegenerative Diseases; Protein Isoforms; Protein Multimerization; Protein Structure, Quaternary; Protein Structure, Tertiary

To clarify the role of α-synuclein (αSyn) in neuronal membrane remodeling, we analyzed the expression of αSyn in neurons with a dysfunction of PLA2G6, which is indispensable for membrane remodeling. αSyn/phosphorylated-αSyn (PαSyn) distribution and neurodegeneration were quantitatively estimated in PLA2G6-knockout (KO) mice, which demonstrate marked mitochondrial membrane degeneration. We also assessed the relationship between αSyn deposits and mitochondria in brain tissue from patients with PLA2G6-associated neurodegeneration (PLAN) and Parkinson's disease (PD), and quantitatively examined Lewy bodies (LBs) and neurons. The expression level of αSyn was elevated in PLA2G6-knockdown cells and KO mouse neurons. Strong PαSyn expression was observed in neuronal granules in KO mice before onset of motor symptoms. The granules were mitochondrial outer membrane protein (TOM20)-positive. Ultramicroscopy revealed that PαSyn-positive granules were localized to mitochondria with degenerated inner membranes. After symptom onset, TOM20-positive granules were frequently found in ubiquitinated spheroids, where PαSyn expression was low. Axons were atrophic, but the neuronal loss was not evident in KO mice. In PLAN neurons, small PαSyn-positive inclusions with a TOM20-positive edge were frequently observed and clustered into LBs. The surfaces of most LBs were TOM20-positive in PLAN and TOM20-negative in PD brains. The high proportion of LB-bearing neurons and the preserved neuronal number in PLAN suggested long-term survival of LB-bearing neurons. Elevated expression of αSyn/PαSyn in mitochondria appears to be the early response to PLA2G6-deficiency in neurons. The strong affinity of αSyn for damaged mitochondrial membranes may promote membrane stabilization of mitochondria and neuronal survival in neurons.

Topics: Age Factors; Aged; Aged, 80 and over; alpha-Synuclein; Animals; Brain; Cell Line, Tumor; Female; Gene Expression Regulation; Group VI Phospholipases A2; Humans; Lewy Bodies; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Middle Aged; Mitochondria; Mitochondrial Membranes; Neuroblastoma; Neurodegenerative Diseases; Neurons; Parkinson Disease; Posterior Horn Cells; Sciatic Nerve; Spinal Cord

The quantification of four distinct proteins (α-synuclein, β-amyloid1-42, DJ-1, and total tau) in cerebrospinal fluid (CSF) has been proposed as a laboratory-based platform for the diagnosis of Parkinson's disease (PD) and Alzheimer's disease (AD). While there is some clinical utility in measuring these markers individually, their usage in routine clinical testing remains challenging, in part due to substantial overlap of concentrations between healthy controls and diseased subjects. In contrast, measurement of different analytes in a single sample from individual patients in parallel appears to considerably improve the accuracy of AD or PD diagnosis. Here, we report the development and initial characterization of a first, electrochemiluminescence-based multiplex immunoassay for the simultaneous quantification of all four proteins ('tetraplex') in as little as 50 μl of CSF. In analytical performance experiments, we assessed its sensitivity, spike-recovery rate, parallelism and dilution linearity as well as the intra- and inter-assay variability. Using our in-house calibrators, we recorded a lower limit of detection for α-synuclein, β-amyloid42, DJ-1, and t-tau of 1.95, 1.24, 5.63, and 4.05 pg/ml, respectively. The corresponding, linear concentration range covered >3 orders of magnitude. In diluted CSF samples (up to 1:4), spike-recovery rates ranged from a low of 55% for β-amyloid42 to a high of 98% for DJ-1. Hillslopes ranged from 1.03 to 1.30, and inter-assay variability demonstrated very high reproducibility. Our newly established tetraplex assay represents a significant technical advance for fluid-based biomarker studies in neurodegenerative disorders allowing the simultaneous measurement of four pivotal makers in single CSF specimens. It provides exceptional sensitivity, accuracy and speed.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Enzyme-Linked Immunosorbent Assay; Humans; Limit of Detection; Neurodegenerative Diseases; Parkinson Disease; Peptide Fragments; Protein Deglycase DJ-1; Reproducibility of Results; tau Proteins

Parkinson's Disease (PD) is an age-related, chronic neurodegenerative disorder. At present, there are no disease-modifying therapies to prevent PD progression. Activated microglia and neuroinflammation are associated with the pathogenesis and progression of PD. Accumulation of α-synuclein (α-SYN) in the brain is a core feature of PD and leads to microglial activation, inflammatory cytokine/chemokine production, and ultimately to neurodegeneration. Given the importance of the JAK/STAT pathway in activating microglia and inducing cytokine/chemokine expression, we investigated the therapeutic potential of inhibiting the JAK/STAT pathway using the JAK1/2 inhibitor, AZD1480. In vitro, α-SYN exposure activated the JAK/STAT pathway in microglia and macrophages, and treatment with AZD1480 inhibited α-SYN-induced major histocompatibility complex Class II and inflammatory gene expression in microglia and macrophages by reducing STAT1 and STAT3 activation. For in vivo studies, we used a rat model of PD induced by viral overexpression of α-SYN. AZD1480 treatment inhibited α-SYN-induced neuroinflammation by suppressing microglial activation, macrophage and CD4(+) T-cell infiltration and production of proinflammatory cytokines/chemokines. Numerous genes involved in cell-cell signaling, nervous system development and function, inflammatory diseases/processes, and neurological diseases are enhanced in the substantia nigra of rats with α-SYN overexpression, and inhibited upon treatment with AZD1480. Importantly, inhibition of the JAK/STAT pathway prevented the degeneration of dopaminergic neurons in vivo These results indicate that inhibiting the JAK/STAT pathway can prevent neuroinflammation and neurodegeneration by suppressing activation of innate and adaptive immune responses to α-SYN. Furthermore, this suggests the feasibility of targeting the JAK/STAT pathway as a neuroprotective therapy for neurodegenerative diseases.. α-SYN plays a central role in the pathophysiology of PD through initiation of neuroinflammatory responses. Using an α-SYN overexpression PD model, we demonstrate a beneficial therapeutic effect of AZD1480, a specific inhibitor of JAK1/2, in suppressing neuroinflammation and neurodegeneration. Our findings document that inhibition of the JAK/STAT pathway influences both innate and adaptive immune responses by suppressing α-SYN-induced microglia and macrophage activation and CD4(+) T-cell recruitment into the CNS, ultimately suppressing neurodegeneration. These findings are the first documentation that suppression of the JAK/STAT pathway disrupts the circuitry of neuroinflammation and neurodegeneration, thus attenuating PD pathogenesis. JAK inhibitors may be a viable therapeutic option for the treatment of PD patients.

Topics: alpha-Synuclein; Animals; Dopaminergic Neurons; Inflammation; Janus Kinases; Macrophages; Male; Mice; Mice, Inbred C57BL; Microglia; Neurodegenerative Diseases; Neuroprotective Agents; Parkinson Disease; Pyrazoles; Pyrimidines; Rats; Rats, Sprague-Dawley; STAT Transcription Factors

Dietary restriction (DR) has been shown to increase longevity, delay onset of aging, reduce DNA damage and oxidative stress and prevent age-related decline of neuronal activity. We previously reported the role of altered ubiquitin proteasome system (UPS) in the neuronal cell death in a spontaneous obese rat model (WNIN/Ob rat). In this study, we investigated the effect of DR on obesity-induced neuronal cell death in a rat model. Two groups of 40-day-old WNIN/Ob rats were either fed ad libitum (Ob) or pair-fed with lean. The lean phenotype of WNIN/Ob rats served as ad libitum control. These animals were maintained for 6.5months on their respective diet regime. At the end of the study, cerebral cortex was collected and markers of UPS, endoplasmic reticulum (ER) stress and autophagy were analyzed by quantitative real-time polymerase chain reaction, immunoblotting and immunohistochemistry. Chymotrypsin-like activity of proteasome was assayed by the fluorimetric method. Apoptotic cells were analyzed by TUNEL assay. DR improved metabolic abnormalities in obese rats. Alterations in UPS (up-regulation of UCHL1, down-regulation of UCHL5, declined proteasomal activity), increased ER stress, declined autophagy and increased expression of α-synuclein, p53 and BAX were observed in obese rats and DR alleviated these changes in obese rats. Further, DR decreased TUNEL-positive cells. In conclusion, DR in obese rats could not only restore the metabolic abnormalities but also preserved neuronal health in the cerebral cortex by preventing alterations in the UPS.

Topics: Aging; alpha-Synuclein; Animals; Apoptosis; Autophagy; bcl-2-Associated X Protein; Biomarkers; Caloric Restriction; Cerebral Cortex; Endoplasmic Reticulum Stress; Gene Expression Regulation, Developmental; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Neuroprotection; Obesity; Proteasome Endopeptidase Complex; Rats, Mutant Strains; Tumor Suppressor Protein p53; Ubiquitination

A majority of current disease-modifying therapeutic approaches for age-related neurodegenerative diseases target their characteristic proteopathic lesions (α-synuclein, Tau, Aβ). To monitor such treatments, fluid biomarkers reflecting the underlying disease process are crucial. We found robust increases of neurofilament light chain (NfL) in CSF and blood in murine models of α-synucleinopathies, tauopathy, and β-amyloidosis. Blood and CSF NfL levels were strongly correlated, and NfL increases coincided with the onset and progression of the corresponding proteopathic lesions in brain. Experimental induction of α-synuclein lesions increased CSF and blood NfL levels, while blocking Aβ lesions attenuated the NfL increase. Consistently, we also found NfL increases in CSF and blood of human α-synucleinopathies, tauopathies, and Alzheimer's disease. Our results suggest that CSF and particularly blood NfL can serve as a reliable and easily accessible biomarker to monitor disease progression and treatment response in mouse models and potentially in human proteopathic neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Axons; Biomarkers; Brain; Disease Progression; Intermediate Filaments; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Neurofilament Proteins

Common neurodegenerative proteinopathies, such as Alzheimer's disease (AD) and Parkinson's disease (PD), are characterized by the misfolding and aggregation of toxic protein species, including the amyloid beta (Aß) peptide, microtubule-associated protein Tau (Tau), and alpha-synuclein (αSyn) protein. These factors also show toxicity in Drosophila; however, potential limitations of prior studies include poor discrimination between effects on the adult versus developing nervous system and neuronal versus glial cell types. In addition, variable expression paradigms and outcomes hinder systematic comparison of toxicity profiles. Using standardized conditions and medium-throughput assays, we express human Tau, Aß or αSyn selectively in neurons of the adult Drosophila retina and monitor age-dependent changes in both structure and function, based on tissue histology and recordings of the electroretinogram (ERG), respectively. We find that each protein causes a unique profile of neurodegenerative pathology, demonstrating distinct and separable impacts on neuronal death and dysfunction. Strikingly, expression of Tau leads to progressive loss of ERG responses whereas retinal architecture and neuronal numbers are largely preserved. By contrast, Aß induces modest, age-dependent neuronal loss without degrading the retinal ERG. αSyn expression, using a codon-optimized transgene, is characterized by marked retinal vacuolar change, progressive photoreceptor cell death, and delayed-onset but modest ERG changes. Lastly, to address potential mechanisms, we perform transmission electron microscopy (TEM) to reveal potential degenerative changes at the ultrastructural level. Surprisingly, Tau and αSyn each cause prominent but distinct synaptotoxic profiles, including disorganization or enlargement of photoreceptor terminals, respectively. Our findings highlight variable and dynamic properties of neurodegeneration triggered by these disease-relevant proteins in vivo, and suggest that Drosophila may be useful for revealing determinants of neuronal dysfunction that precede cell loss, including synaptic changes, in the adult nervous system.

Topics: Aging; alpha-Synuclein; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Cell Death; Disease Models, Animal; Drosophila; Electroretinography; Female; Humans; Membrane Potentials; Microelectrodes; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Neurons; Peptide Fragments; Retina; tau Proteins; Vision, Ocular

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

Aggregation of α-synuclein contributes to the formation of Lewy bodies and neurites, the pathologic hallmarks of Parkinson disease (PD) and α-synucleinopathies. Although a number of human mutations have been identified in familial PD, the mechanisms that promote α-synuclein accumulation and toxicity are poorly understood. Here, we report that hyperactivity of the nonreceptor tyrosine kinase c-Abl critically regulates α-synuclein-induced neuropathology. In mice expressing a human α-synucleinopathy-associated mutation (hA53Tα-syn mice), deletion of the gene encoding c-Abl reduced α-synuclein aggregation, neuropathology, and neurobehavioral deficits. Conversely, overexpression of constitutively active c-Abl in hA53Tα-syn mice accelerated α-synuclein aggregation, neuropathology, and neurobehavioral deficits. Moreover, c-Abl activation led to an age-dependent increase in phosphotyrosine 39 α-synuclein. In human postmortem samples, there was an accumulation of phosphotyrosine 39 α-synuclein in brain tissues and Lewy bodies of PD patients compared with age-matched controls. Furthermore, in vitro studies show that c-Abl phosphorylation of α-synuclein at tyrosine 39 enhances α-synuclein aggregation. Taken together, this work establishes a critical role for c-Abl in α-synuclein-induced neurodegeneration and demonstrates that selective inhibition of c-Abl may be neuroprotective. This study further indicates that phosphotyrosine 39 α-synuclein is a potential disease indicator for PD and related α-synucleinopathies.

Topics: Aged; alpha-Synuclein; Animals; Brain; Disease Models, Animal; Female; Gene Deletion; HEK293 Cells; Humans; Lewy Bodies; Male; Mice; Mice, Transgenic; Mutation; Neurites; Neurodegenerative Diseases; Neuroprotection; Parkinson Disease; Phosphorylation; Phosphotyrosine; Proto-Oncogene Proteins c-abl

Idiopathic Parkinson's disease (IPD) is a neurodegenerative disorder characterized by selective degeneration of the substantia nigra pars compacta (SNc), dorsal motor nucleus of the vagus and other vulnerable nervous system regions characterized by extensive axonal arborization and intense energy requirements. Systemic age-related depression of mitochondrial function, oxidative phosphorylation (OXPHOS) and depressed expression of genes supporting energy homeostasis is more severe in IPD than normal aging such that energy supply may exceed regional demand. In IPD, the overall risk of malignancy is reduced. Cancer is a collection of proliferative diseases marked by malignant transformation, dysregulated mitosis, invasion and metastasis. Many cancers demonstrate normal mitochondrial function, preserved OXPHOS, competent mechanisms of energy homeostasis, and metabolic reprogramming capacities that are lacking in IPD. Metabolic reprogramming adjusts OXPHOS and glycolytic pathways in response to changing metabolic needs. These opposite metabolic features form the basis of a two component hypothesis. First, that depressed mitochondrial function, OXPHOS deficiency and impaired metabolic reprogramming contribute to focal energy failure, neurodegeneration and disease expression in IPD. Second, that the same systemic metabolic deficits inhibit development and proliferation of malignancies in IPD. Studies of mitochondrial aging, familial PD (FPD), the lysosomal storage disorder, Gaucher's disease, Parkinson's disease cybrids, the mitochondrial cytopathies, and disease-related metabolic reprogramming both in IPD and cancer provide support for this model.

Topics: Aging; alpha-Synuclein; Animals; Homeostasis; Humans; Lysosomes; Mice; Mitochondria; Mitochondrial Diseases; Mitophagy; Models, Theoretical; Mutation; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasms; Neurodegenerative Diseases; Oxidative Phosphorylation; Parkinson Disease; Risk; Substantia Nigra

Synucleinopathies, including Parkinson's disease (PD), are neurodegenerative diseases characterized by accumulation of α-synuclein (SYN), a small neuronal protein with prion like properties that plays a central role in PD pathogenesis. SYN can misfold and generate toxic oligomers/aggregates, which can be cytotoxic. Environmental arsenic (As)-containing pesticide use correlates with increased incidence of PD. Moreover, because As exposure can lead to inhibition of autophagic flux we hypothesize that As can facilitate the accumulation of toxic SYN oligomers/aggregates and subsequent increases in markers of autophagy. We therefore examined the role of As in the oligomerization of SYN, and the consequences thereof. Chronic exposure of SH-SY5Y cells overexpressing SYN to As caused a dose-dependent oligomerization of SYN, with concomitant increases in protein ubiquitination and expression of other stress markers (protein glutathione binding, γ-GCS, light chain 3 (LC3)-I/II, P62, and NAD(P)H dehydrogenase quinone 1), indicative of an increased proteotoxic stress. Immunocytochemical analyses revealed an accumulation of SYN, and it's colocalization with LC3, a major autophagic protein. Mice exposed to As (100 ppb) for 1 month, exhibited elevated SYN accumulation in the cortex and striatum, and elevations in protein ubiquitination and LC3-I and II levels. However, tyrosine hydroxylase (TH), an indicator of dopaminergic cell density, was upregulated in the As exposed animals. Because SYN can inhibit TH function, and As can decrease monoamine levels, As exposure possibly leads to compensatory mechanisms leading to an increase in TH expression. Our findings suggest that susceptible individuals may be at higher risk of developing synucleinopathies and/or neurodegeneration due to environmental As exposure.

Topics: alpha-Synuclein; Animals; Arsenic; Cell Line; Female; Mice; Neurodegenerative Diseases; Parkinson Disease

Parkinson's disease (PD) is characterized by the accumulation of α-synuclein (α-syn) within Lewy body inclusions in the nervous system. There are currently no disease-modifying therapies capable of reducing α-syn inclusions in PD. Recent data has indicated that loss-of-function mutations in the GBA1 gene that encodes lysosomal β-glucocerebrosidase (GCase) represent an important risk factor for PD, and can lead to α-syn accumulation. Here we use a small-molecule modulator of GCase to determine whether GCase activation within lysosomes can reduce α-syn levels and ameliorate downstream toxicity. Using induced pluripotent stem cell (iPSC)-derived human midbrain dopamine (DA) neurons from synucleinopathy patients with different PD-linked mutations, we find that a non-inhibitory small molecule modulator of GCase specifically enhanced activity within lysosomal compartments. This resulted in reduction of GCase substrates and clearance of pathological α-syn, regardless of the disease causing mutations. Importantly, the reduction of α-syn was sufficient to reverse downstream cellular pathologies induced by α-syn, including perturbations in hydrolase maturation and lysosomal dysfunction. These results indicate that enhancement of a single lysosomal hydrolase, GCase, can effectively reduce α-syn and provide therapeutic benefit in human midbrain neurons. This suggests that GCase activators may prove beneficial as treatments for PD and related synucleinopathies.. The presence of Lewy body inclusions comprised of fibrillar α-syn within affected regions of PD brain has been firmly documented, however no treatments exist that are capable of clearing Lewy bodies. Here, we used a mechanistic-based approach to examine the effect of GCase activation on α-syn clearance in human midbrain DA models that naturally accumulate α-syn through genetic mutations. Small molecule-mediated activation of GCase was effective at reducing α-syn inclusions in neurons, as well as associated downstream toxicity, demonstrating a therapeutic effect. Our work provides an example of how human iPSC-derived midbrain models could be used for testing potential treatments for neurodegenerative disorders, and identifies GCase as a critical therapeutic convergence point for a wide range of synucleinopathies.

Topics: alpha-Synuclein; Cell Differentiation; Cell Line, Tumor; Dopaminergic Neurons; Enzyme Inhibitors; Gene Expression Regulation; Glucosylceramidase; Humans; Induced Pluripotent Stem Cells; Lysosomal-Associated Membrane Protein 2; Lysosomes; Mesencephalon; Mutation; Neuroblastoma; Neurodegenerative Diseases; Parkinson Disease; Proton-Translocating ATPases; Subcellular Fractions; Synaptophysin

Iron, as well as copper, is essential for a wide variety of biological processes in living organisms, however, dysregulation of iron homeostasis may lead to oxidative stress via redox cycling reactions. Therefore, cellular and systemic iron homeostasis is tightly regulated by a number of iron metabolism proteins. The brain is susceptible to iron-mediated oxidative damage because of a relatively high content of iron and high consumption of oxygen. Iron-mediated neurotoxicity is symbolically seen in neurodegeneration with brain iron accumulation (NBIA) in which iron accumulates mainly in the basal ganglia. Furthermore, iron accumulation is considered to play important roles in the pathophysiology of other, more prevalent neurodegenerative diseases such as Parkinson's disease (PD). Here, from the standpoint of iron dyshomeostasis, current understandings and therapeutic approaches in NBIA and PD are briefly discussed.

Topics: alpha-Synuclein; Brain; Humans; Iron; Magnetic Resonance Imaging; Neurodegenerative Diseases

Topics: alpha-Synuclein; Biological Assay; Humans; Neurodegenerative Diseases

Topics: alpha-Synuclein; Blood-Brain Barrier; Clinical Trials as Topic; Drug Discovery; Enzyme Replacement Therapy; Humans; Lysosomal Storage Diseases; Lysosomes; Neurodegenerative Diseases

Pathological protein deposits in oligodendroglia are common but variable features of various neurodegenerative conditions. To evaluate oligodendrocyte response in neurodegenerative diseases (NDDs) with different extents of oligodendroglial protein deposition we performed immunostaining for tubulin polymerization-promoting protein p25α (TPPP/p25α), α-synuclein (α-syn), phospho-tau, ubiquitin, myelin basic protein, and the microglial marker HLA-DR. We investigated cases of multiple system atrophy ([MSA] n = 10), Lewy body disease ([LBD] n = 10), globular glial tauopathy ([GGT] n = 7) and progressive supranuclear palsy ([PSP] n = 10). Loss of nuclear TPPP/p25α immunoreactivity correlated significantly with the degree of microglial reaction and loss of myelin basic prtein density as a marker of tract degeneration. This was more prominent in MSA and GGT, which, together with enlarged cytoplasmic TPPP/p25α immunoreactivity and inclusion burden allowed these disorders to be grouped as predominant oligodendroglial proteinopathies. However, distinct features, ie more colocalization of α-syn than tau with TPPP/p25α, more obvious loss of oligodendrocyte density in MSA, but more prominent association of tau protein inclusions in GGT to loss of nuclear TPPP/p25α immunoreactivity, were also recognized. In addition, we observed previously underappreciated oligodendroglial α-synuclein pathology in the pallidothalamic tract in LBD. Our study demonstrates common and distinct aspects of oligodendroglial involvement in the pathogenesis of diverse NDDs.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Brain; Female; Humans; Male; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases; Oligodendroglia; tau Proteins; Tauopathies

Mitochondrial and autophagic dysfunction as well as neuroinflammation are involved in the pathophysiology of Parkinson's disease (PD). We hypothesized that targeting the mitochondrial pyruvate carrier (MPC), a key controller of cellular metabolism that influences mTOR (mammalian target of rapamycin) activation, might attenuate neurodegeneration of nigral dopaminergic neurons in animal models of PD. To test this, we used MSDC-0160, a compound that specifically targets MPC, to reduce its activity. MSDC-0160 protected against 1-methyl-4-phenylpyridinium (MPP

Topics: 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Autophagy; Behavior, Animal; Brain; Caenorhabditis elegans; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Heterozygote; Humans; Inflammation; Male; Mice; Mice, Inbred C57BL; Mitochondria; Neurodegenerative Diseases; Neurons; Oxygen Consumption; Parkinson Disease; Pyridines; Pyruvic Acid; Signal Transduction; Substantia Nigra; Thiazolidinediones

Specific extracellular deposits, glial or neuronal inclusions help defining an ever increasing number of neurodegenerative diseases. Deposits or inclusions are aggregates of proteins: Aβ peptide and tau proteins in Alzheimer disease, a-synuclein in Parkinson disease, for instance. The protein that specifically accumulates in a given disease may be modified by a mutation that can increase its aggregability. Most often the sequence of the protein is normal. Misfolding, despite the protein normal sequence, is then considered the cause of the aggregation. The ubiquitin-proteasome system detects and eliminates misfolded proteins from the cell. Almost all the inclusions are indeed labeled by anti-ubiquitin antibodies, but, in neurodegenerative diseases, the system is unable to get rid of them. The large protein aggregates constituting the inclusions are poorly reactive. Their formation has been consi- dered a defense mechanism, protecting the cell against the toxic action of soluble oligomers that are, in that hypothesis, the real toxic agent, neutralized through aggregation. Soluble oligomers of Aβ peptide, tau or a-synuclein,for instance, have indeed been isolated and were shown to be toxic. In the prion hypothesis, the misfolded configuration may be passed from the misfolded to the normal protein by simple contact. There are indeed experimental evidences suggesting that this prion-like mechanism does occur in transgenic rodent models of Aβ, tau or a-synuclein pathology. This might be the explanation of thepropagation of the pathology through connections, observed in many neurodegenerative diseases. There is currently no epidemiological data suggesting a transmission of neurodegenerative diseases, comparable to the transmission of Creutzfeldt-Jakob or other prion diseases. The prion-like mechanisms of protein aggregation observed in the experimental animals or suspected through human neuropathology make that possibility not as remote as previously thought.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Humans; Neurodegenerative Diseases; Proteostasis Deficiencies; tau Proteins

Topics: alpha-Synuclein; Animals; Brain Stem; Dentate Gyrus; Female; Formaldehyde; Immunoblotting; Immunohistochemistry; Mice, Transgenic; Neurodegenerative Diseases; Proteostasis Deficiencies; Survival Analysis; Tissue Extracts; Tissue Fixation

This study was to explore the molecular mechanisms underpinning the synergetic effect between β-amyloid (Aβ) and α-synuclein (α-syn) on synapses dysfunction during the development of neurodegenerative disorders including Parkinson's disease (PD), dementia with Lewy bodies (DLB) and Alzheimer disease (AD).. The primary cultured hippocampal neurons prepared from the fetal tissue of mice were divided into six groups and treated with DMSO, Aβ(42-1), α-syn, Aβ(1-42), α-syn plus Aβ(42-1) and α-syn plus Aβ(1-42), respectively. After incubation for 24 h, the synapsin I content was calculated by immunofluorescence and the synaptic vesicle recycling was monitored by FM1-43 staining. Furthermore, the expression of cysteine string protein-α (CSPα) detected by western blot was also conducted.. Either Aβ(1-42) or α-syn alone could induce a significant synapses dysfunction through reducing the content of synapsin I, inhibiting the synaptic vesicle recycling as well as down-regulating the expression of CSPα compared with the controls (P<0.05). However, simultaneous intervention with both α-syn and Aβ(1-42) aggravated these effects in cultured hippocampal neurons compared with the treatment with α-syn (synapsin I content: P<0.001; synaptic vesicle recycling: P=0.007; CSPα expression: P<0.001) or Aβ(1-42) (synapsin I number: P<0.001; synaptic vesicle recycling: P=0.007 CSPα expression: P<0.001) alone.. There was synergistic effect between Aβ and α-syn on synapses dysfunction through reducing the synapsin I content, inhibiting the synaptic vesicle recycling and down-regulating the expression of CSPα in several neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Blotting, Western; Cells, Cultured; Fluorescent Antibody Technique; Hippocampus; HSP40 Heat-Shock Proteins; Membrane Proteins; Mice; Neurodegenerative Diseases; Neurons; Synapses; Synapsins; Synaptic Vesicles

Protein misfolding and aggregation is a major hallmark of neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Until recently, the consensus was that each aggregation-prone protein was characteristic of each disorder [α-synuclein (α-syn)/PD, mutant huntingtin (Htt)/HD, Tau and amyloid beta peptide/AD]. However, growing evidence indicates that aggregation-prone proteins can actually co-aggregate and modify each other's behavior and toxicity, suggesting that this process may also contribute to the overlap in clinical symptoms across different diseases. Here, we show that α-syn and mutant Htt co-aggregate in vivo when co-expressed in Drosophila and produce a synergistic age-dependent increase in neurotoxicity associated to a decline in motor function and life span. Altogether, our results suggest that the co-existence of α-syn and Htt in the same neuronal cells worsens aggregation-related neuropathologies and accelerates disease progression.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Disease Models, Animal; Drosophila; Female; Humans; Huntingtin Protein; Male; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Aggregates

Amyloid fibrils associated with neurodegenerative diseases, such as Parkinson's and Alzheimer's, consist of insoluble aggregates of α-synuclein and Aβ-42 proteins with a high β-sheet content. The aggregation of both proteins occurs by misfolding of the monomers and proceeds through the formation of intermediate oligomeric and protofibrillar species to give the final fibrillar cross-β-sheet structure. The morphological and mechanical properties of oligomers, protofibrils, and fibrils formed during the fibrillization process were investigated by thioflavin T fluorescence and circular dichroism in combination with AFM peak force quantitative nanomechanical technique. The results reveal an increase in the Young's modulus during the transformation from oligomers to mature fibrils, thus inferring that the difference in their mechanical properties is due to an internal structural change from a random coil to a structure with increased β-sheet content.

Topics: alpha-Synuclein; Amyloid; Amyloid beta-Peptides; Elastic Modulus; Humans; Microscopy, Atomic Force; Neurodegenerative Diseases; Peptide Fragments; Protein Structure, Secondary

Historically, control brain tissue was classified as such mainly by clinical history, and underwent limited neuropathological analysis. Significant progress has been made in recent years with the collection of more extensive clinical information and more specific classifications of neurodegenerative disease, aided by advances in histological processing and increasingly sensitive detection methods. We hypothesised that this may have resulted in certain pathologies previously going unidentified, due to insufficient block sampling and an inadequate range of stains, resulting in the disease not being recognised. We therefore investigated the significance of changes to our own protocols for examining control brain tissue before and after 2007. Control cases that were originally assessed before 2007 were re-assessed using our current staining protocol and antibodies, and compared with age-matched cases post-2007. We found that almost all cases that were originally described as neuropathologically normal displayed some level of pathology after re-analysis, with four cases displaying what we have termed 'major' pathology that previously went unidentified, emphasising on a small scale the importance of accurate neuropathological analysis of control tissue, and highlighting the inherent difficulty of traditionally classifying tissue simply as 'disease' or 'control'. We hope our findings will stimulate debate within the brain banking community, with the eventual aim being standardisation of protocols for assessing controls across brain banks.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Brain; DNA-Binding Proteins; Female; Humans; Longitudinal Studies; Male; Neurodegenerative Diseases; tau Proteins; Tissue Banks

Spreading of misfolded proteins has been suggested for neurodegenerative diseases. The hierarchical distribution of protein deposits in Alzheimer's (AD) and Parkinson's disease (PD) supports this concept.. To evaluate α-synuclein and tau-deposition in the optic pathway as an excellent anatomical model, which follows a strict trajectory including a cortico-geniculate feedback connection.. We immunostained the optic nerve, lateral geniculate nucleus (LGN), and occipital cortex for AT8 (phosphorylated tau), α-synuclein, and disease-associated prion protein (PrP) in 47 cases with tau pathology (AD type, argyrophilic grain disease, or progressive supranuclear palsy), 16 PD, and 5 Creutzfeldt-Jakob disease (CJD) cases, respectively.. We detected immunoreactivity for all proteins along the optic pathway. The optic nerve showed immunopositivity only in cases with tau (6/8, 75%) or α-synuclein (5/7, 71%) pathology. The LGN was involved also frequently (tau: 22/47, 46.8% ; α-synuclein: 15/16, 93.7% ; PrP 5/5, 100%). The occipital cortex was variably affected by tau or α-synuclein pathology, but always showed PrP immunoreactivity in the CJD cases. Tau pathology in the LGN correlated with tau immunoreactivity in the occipital cortex and Braak stages of neurofibrillary degeneration. In tauopathies, which do not involve the occipital cortex, like argyrophilic grain disease or progressive supranuclear palsy, tau pathology was more frequently astrocytic in the LGN.. Our results have implications 1) for the understanding of disease spreading along neural pathways and 2) for the diagnostic evaluation of the visual system in neurodegenerative proteinopathies as a potential biomarker to evaluate disease progression or subgrouping of cases.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Creutzfeldt-Jakob Syndrome; Geniculate Bodies; Humans; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; Occipital Lobe; Optic Nerve; Phosphorylation; Prions; Supranuclear Palsy, Progressive; tau Proteins; Visual Pathways

This is an Editorial highlighting the article "Extracellular α-synuclein alters synaptic transmission in rain neurons by perforating the neuronal plasma membrane" by Pacheco and coauthors, in this issue of Journal of Neurochemistry. The authors demonstrate, using a variety of techniques, that alpha-synuclein possesses neurotoxicity toward brain neuronal plasma membranes exposed directly to extracellular alpha-synuclein oligomers. Extracellular oligomeric α-synuclein rapidly associates to hippocampal membranes and induces pore formation in the hippocampal cells. This increases membrane conductance and calcium influx. Oligomeric α-synuclein also induces changes in synaptic current activity in hippocampal neurons. The authors' findings support the pathogenic role of extracellular alpha-synuclein in the brain, and should provide a new strategy for the treatment of Parkinson's disease and other synucleinopathies, neurodegenerative diseases with aberrant accumulation of aggregated alpha-synuclein in neurons, nerve fibers or glial cells. Read the full article 'Extracellular α-synuclein alters synaptic transmission in brain neurons by perforating the neuronal plasma membrane' on page 731.

Topics: alpha-Synuclein; Animals; Cell Membrane; Cell Membrane Permeability; Humans; Neurodegenerative Diseases; Neurons; Synaptic Transmission

Impairment of the enteric nervous system has been suggested to occur within the pathogenesis of neurodegenerative diseases. Thus, in the current study, we consider salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, SAL) as a substance that can potentially induce myenteric neurodegen-eration.. Male Wistar rats were subjected to continuous intraperitoneal dosing of salsolinol (200 mg/kg in total) with osmotic mini-pumps for either two or four weeks. An equivalent group of rats served as the control. Jejunal myenteric neurons were subjected to immunofluorescence staining to detect neuron specific protein - protein gene product (pan-neuronal marker, PGP 9.5), nitric oxide synthase (NOS), choline acetyltransferase (ChAT), Bax-protein and alpha-synuclein. In search of any functional impairment within the gastrointestinal tract, gut motility was assessed by determining the residual solid food contents in the stomach and the small and large intestine transit.. The myenteric neuron count, the mean size of the neuron body, the area of ganglia and the diameter of nerve strands were decreased in both of the salsolinol-treated groups compared with the controls. The number of NOS-positive cells was lower in the salsolinol-treated groups, while the number of ChAT-positive cells remained unchanged in comparison with the controls. Neurons expressing the pro-apoptotic Bax protein and alpha-synuclein deposits were observed among the myenteric neurons of the salsolinol-treated rats.. Salsolinol evokes enteric neuronal cell death via initiation of apoptosis and leads to the formation of pathological aggregates of alpha-synuclein. Impairment of myenteric neurons, mainly the inhibitory motor neurons, might be responsible for the abnormal intestinal transit. Thus, salsolinol might be regarded as a suitable compound for inducing experimental enteric neurodegeneration in rats.

Topics: alpha-Synuclein; Animals; Apoptosis; bcl-2-Associated X Protein; Choline O-Acetyltransferase; Injections, Intraperitoneal; Intestinal Pseudo-Obstruction; Isoquinolines; Male; Myenteric Plexus; Neurodegenerative Diseases; Neurons; Nitric Oxide Synthase; Rats; Rats, Wistar; Ubiquitin Thiolesterase

Substantial interest persists for developing neurotrophic factors to treat neurodegenerative diseases. At the same time, significant progress has been made in implementing gene therapy as a means to provide long-term expression of bioactive neurotrophic factors to targeted sites in the brain. Nonetheless, to date, no double-blind clinical trial has achieved positive results on its primary endpoint despite robust benefits achieved in animal models. A major issue with advancing the field is the paucity of information regarding the expression and effects of neurotrophic factors in human neurodegenerative brain, relative to the well-characterized responses in animal models. To help fill this information void, we examined post-mortem brain tissue from four patients with nigrostriatal degeneration who had participated in clinical trials testing gene delivery of neurturin to the putamen of patients. Each had died of unrelated causes ranging from 1.5-to-3-months (2 Parkinson's disease patients), to 4+-years (1 Parkinson's disease and 1 multiple-system atrophy-parkinsonian type patient) following gene therapy. Quantitative and immunohistochemical evaluation of neurturin, alpha-synuclein, tyrosine hydroxylase (TH) and an oligodendroglia marker (Olig 2) were performed in each brain. Comparable volumes-of-expression of neurturin were seen in the putamen in all cases (~15-22%; mean=18.5%). TH-signal in the putamen was extremely sparse in the shorter-term cases. A 6-fold increase was seen in longer-term cases, but was far less than achieved in animal models of nigrostriatal degeneration with similar or even far less NRTN exposure. Less than 1% of substantia nigra (SN) neurons stained for neurturin in the shorter-term cases. A 15-fold increase was seen in the longer-term cases, but neurturin was still only detected in ~5% of nigral cells. These data provide unique insight into the functional status of advanced, chronic nigrostriatal degeneration in human brain and the response of these neurons to neurotrophic factor stimulation. They demonstrate mild but persistent expression of gene-mediated neurturin over 4-years, with an apparent, time-related amplification of its transport and biological effects, albeit quite weak, and provide unique information to help plan and design future trials.

Topics: Aged; alpha-Synuclein; Basic Helix-Loop-Helix Transcription Factors; Corpus Striatum; Dependovirus; Genetic Therapy; Genetic Vectors; Humans; Middle Aged; Nerve Tissue Proteins; Neural Pathways; Neurodegenerative Diseases; Neurons; Neurturin; Oligodendrocyte Transcription Factor 2; Substantia Nigra; Tyrosine 3-Monooxygenase

Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is a neurodegenerative disease clinically characterized by slowly progressive cognitive decline and motor dysfunction. Neuropathology shows diffuse degeneration in the white matter, with prominent presence of widespread axonal spheroids. To investigate the mechanism underlying HDLS neurodegeneration, we characterized spheroids and examined their development in the degenerated white matter. Analysis revealed that the spheroids are an early neuropathological manifestation in the white matter degeneration and involve axonal component proteins and α-synuclein. The development of spheroids facilitates in initiating neurodegeneration in HDLS.

Topics: Adult; alpha-Synuclein; Axons; Female; Humans; Leukoencephalopathies; Magnetic Resonance Imaging; Male; Middle Aged; Neurodegenerative Diseases; Receptor, Macrophage Colony-Stimulating Factor; White Matter

Accumulating evidence suggests that deposition of neurotoxic α-synuclein aggregates in the brain during the development of neurodegenerative diseases like Parkinson's disease can be curbed by anti-aggregation strategies that either disrupt or eliminate toxic aggregates. Curcumin, a dietary polyphenol exhibits anti-amyloid activity but the use of this polyphenol is limited owing to its instability. As chemical modifications in curcumin confiscate this limitation, such efforts are intensively performed to discover molecules with similar but enhanced stability and superior properties. This study focuses on the inhibitory effect of two stable analogs of curcumin viz. curcumin pyrazole and curcumin isoxazole and their derivatives against α-synuclein aggregation, fibrillization and toxicity. Employing biochemical, biophysical and cell based assays we discovered that curcumin pyrazole (3) and its derivative N-(3-Nitrophenylpyrazole) curcumin (15) exhibit remarkable potency in not only arresting fibrillization and disrupting preformed fibrils but also preventing formation of A11 conformation in the protein that imparts toxic effects. Compounds 3 and 15 also decreased neurotoxicity associated with fast aggregating A53T mutant form of α-synuclein. These two analogues of curcumin described here may therefore be useful therapeutic inhibitors for the treatment of α-synuclein amyloidosis and toxicity in Parkinson's disease and other synucleinopathies.

Topics: alpha-Synuclein; Curcumin; Dose-Response Relationship, Drug; Humans; Kinetics; Models, Biological; Mutation; Neurodegenerative Diseases; Protein Aggregates; Protein Aggregation, Pathological; Protein Binding; Protein Multimerization; Structure-Activity Relationship

The study of the genes that are related to the pathogenesis of Parkinson's disease (PD) will improve our understanding of the mechanisms that underlie the development of PD. α-Synuclein is a major protein component of Lewy bodies, which are characteristic structures of PD pathology. Mutations in α-synuclein are closely related to the early onset of autosomal dominant PD. Transgenic flies with mutant α-synuclein (A53T) display neurodegenerative changes that include movement dysfunctions and a loss of dopaminergic neurons in the brain. In the present study, we measured reactive oxygen species (ROS) levels in α-synuclein transgenic flies by monitoring the fluorescence levels of redox-sensitive indicators based on GFP (roGFP) in flies co-expressing roGFP and mutant α-synuclein. We found that the ROS levels were significantly increased in the mutant α-synuclein flies. The elevations in ROS levels were also proportionate to the behavioral disorders and the losses of dopaminergic neurons. We also found that CDDO-Me inhibited the increases in ROS levels in the A53T flies and improved the neurodegenerative changes by activating the Nrf2/antioxidant response element signaling pathway. Selective expression of the Nrf2 homologous gene cncC in the dopaminergic neurons effectively protected against the neurodegenerative phenotype of the A53T α-synuclein flies, compared to the flies that expressed cncC in all neurons. These results indicate that the reductions in oxidative stress that are mediated by the activation of the antioxidant signaling pathway can effectively attenuate the neurotoxicity caused by mutations in α-synuclein.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Drosophila; Drosophila Proteins; Female; Neurodegenerative Diseases; NF-E2-Related Factor 2; Repressor Proteins

The acupuncture or electroacupuncture (EA) shows the therapeutic effect on various neurodegenerative diseases. This effect was thought to be partially achieved by its ability to alleviate existing neuroinflammation and glial dysfunction. In this study, we systematically investigated the effect of EA on abnormal neurochemical changes and motor symptoms in a mouse neurodegenerative disease model.. The transgenic mouse which expresses a mutant α-synuclein (α-syn) protein, A53T α-syn, in brain astrocytic cells was used. These mice exhibit extensive neuroinflammatory and motor phenotypes of neurodegenerative disorders. In this study, the effects of EA on these phenotypic changes were examined in these mice.. EA improved the movement detected in multiple motor tests in A53T mutant mice. At the cellular level, EA significantly reduced the activation of microglia and prevented the loss of dopaminergic neurons in the midbrain and motor neurons in the spinal cord. At the molecular level, EA suppressed the abnormal elevation of proinflammatory factors (tumor necrosis factor-α and interleukin-1β) in the striatum and midbrain of A53T mice. In contrast, EA increased striatal and midbrain expression of a transcription factor, nuclear factor E2-related factor 2, and its downstream antioxidants (heme oxygenase-1 and glutamate-cysteine ligase modifier subunits).. These results suggest that EA possesses the ability to ameliorate mutant α-syn-induced motor abnormalities. This ability may be due to that EA enhances both anti-inflammatory and antioxidant activities and suppresses aberrant glial activation in the diseased sites of brains.

Topics: alpha-Synuclein; Animals; Astrocytes; Calcium-Binding Proteins; Electroacupuncture; Exploratory Behavior; Gait Disorders, Neurologic; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Glutamate-Cysteine Ligase; Heme Oxygenase-1; Membrane Proteins; Mice; Mice, Transgenic; Microfilament Proteins; Motor Activity; Motor Neurons; Muscle Strength; Mutation; Neurodegenerative Diseases; NF-E2-Related Factor 2; Spinal Cord

Brain banks allow researchers access to tissue from well-characterised neurodegenerative disease cases. Fixed tissue employed for diagnosis is often not appropriate for research and frozen tissue is therefore made available. Many brain banks use a protocol where half the brain is fixed and half frozen. Recently a study has shown that there can be asymmetry in protein deposition between the hemispheres especially with tau and TDP-43. We aimed to test this hypothesis by prospectively taking bilateral cortical blocks from 30 brains on arrival, and immunostaining to assess the degree of asymmetry. In 6 out 14 cases of AD (Alzheimer's Disease) (Modified Braak Stage V-VI), there was some asymmetrical staining for tau. In 2 cases, there was moderate discrepancy for tau staining between left and right calcarine cortices. However, careful analysis in both these cases revealed discrepancies in tau staining in adjacent regions even on the same side. The α-synuclein staining showed asymmetry in one case only, the Aβ showed only mild asymmetry in 3 cases of AD. The TDP-43 pathology appeared symmetrical in the 2 cases of frontotemporal lobar degeneration with motor neurone disease, but there was asymmetry noted when seen in conjunction with AD. In conclusion, there is the potential for asymmetrical pathology in neurodegenerative diseases and caution should be maintained when freezing half and fixing half of the brain in neurodegenerative diseases. Nevertheless, marked variability in staining can also be identified in adjacent cortical areas so there is no guarantee that an alternative strategy would be superior.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Brain; DNA-Binding Proteins; Functional Laterality; Humans; Immunohistochemistry; Neurodegenerative Diseases; Prospective Studies; tau Proteins; Tissue Banks; Tissue Preservation

Decreased levels of alpha-synuclein (aSyn) in cerebrospinal fluid (CSF) in Parkinson's disease and related synucleinopathies have been reported, however, not consistently in all cross-sectional studies. To test the performance of one recently released human-specific enzyme-linked immunosorbent assay (ELISA) for the quantification of aSyn in CSF, we carried out a round robin trial with 18 participating laboratories trained in CSF ELISA analyses within the BIOMARKAPD project in the EU Joint Program - Neurodegenerative Disease Research. CSF samples (homogeneous aliquots from pools) and ELISA kits (one lot) were provided centrally and data reported back to one laboratory for data analysis. Our study showed that although factors such as preanalytical sample handling and lot-to-lot variability were minimized by our study design, we identified high variation in absolute values of CSF aSyn even when the same samples and same lots of assays were applied. We further demonstrate that although absolute concentrations differ between laboratories the quantitative results are comparable. With further standardization this assay may become an attractive tool for comparing aSyn measurements in diverse settings. Recommendations for further validation experiments and improvement of the interlaboratory results obtained are given.

Topics: alpha-Synuclein; Biomarkers; Enzyme-Linked Immunosorbent Assay; Europe; Female; Humans; International Cooperation; Male; Neurodegenerative Diseases; Parkinson Disease; Reproducibility of Results; United States

A cellular feature of Parkinson's disease is cytosolic accumulation and amyloid formation of α-synuclein (α-syn), implicating a misregulation or impairment of protein degradation pathways involving the proteasome and lysosome. Within lysosomes, cathepsin D (CtsD), an aspartyl protease, is suggested to be the main protease for α-syn clearance; however, the protease alone only generates amyloidogenic C terminal-truncated species (e.g., 1-94, 5-94), implying that other proteases and/or environmental factors are needed to facilitate degradation and to avoid α-syn aggregation in vivo. Using liquid chromatography-mass spectrometry, to our knowledge, we report the first peptide cleavage map of the lysosomal degradation process of α-syn. Studies of purified mouse brain and liver lysosomal extracts and individual human cathepsins demonstrate a direct involvement of cysteine cathepsin B (CtsB) and L (CtsL). Both CtsB and CtsL cleave α-syn within its amyloid region and circumvent fibril formation. For CtsD, only in the presence of anionic phospholipids can this protease cleave throughout the α-syn sequence, suggesting that phospholipids are crucial for its activity. Taken together, an interplay exists between α-syn conformation and cathepsin activity with CtsL as the most efficient under the conditions examined. Notably, we discovered that CtsL efficiently degrades α-syn amyloid fibrils, which by definition are resistant to broad spectrum proteases. This work implicates CtsB and CtsL as essential in α-syn lysosomal degradation, establishing groundwork to explore mechanisms to enhance their cellular activity and levels as a potential strategy for clearance of α-syn.

Topics: alpha-Synuclein; Animals; Brain; Cathepsin B; Cathepsin D; Cathepsin L; Chromatography, Liquid; Circular Dichroism; Cysteine; Humans; Liver; Lysosomes; Mass Spectrometry; Mice; Neurodegenerative Diseases; Parkinson Disease; Peptide Mapping; Peptides; Phospholipids

With the increase in life expectancy in Brazil, concerns have grown about the most prevalent diseases in elderly people. Among these diseases are neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. Protein deposits related to the development of these diseases can pre-date the symptomatic phases by years. The tau protein is particularly interesting: it might be found in the brainstem and olfactory bulb long before it reaches the limbic cortex, at which point symptoms occur. Of the 14 brains collected in this study, the tau protein was found in the brainstems of 10 (71.42%) and in olfactory bulbs of 3 out 11. Of the 7 individuals who had a final diagnosis of Alzheimer's disease (AD), 6 presented tau deposits in some region of the brainstem. Our data support the idea of the presence of tau protein in the brainstem and olfactory bulb in the earliest stages of AD.

Topics: Age Factors; Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Brain Stem; Female; Humans; Immunohistochemistry; Male; Middle Aged; Neurodegenerative Diseases; Olfaction Disorders; Olfactory Bulb; Phosphorylation; Reference Values; tau Proteins

The quantification of α-Synuclein in cerebrospinal fluid (CSF) as a biomarker has gained tremendous interest in the last years. Several commercially available immunoassays are emerging. We here describe the full validation of one commercially available ELISA assay for the quantification of α-Synuclein in human CSF (Covance alpha-Synuclein ELISA kit). The study was conducted within the BIOMARKAPD project in the European initiative Joint Program for Neurodegenerative Diseases (JPND). We investigated the effect of several pre-analytical and analytical confounders: i.e. (1) need for centrifugation of freshly drawn CSF, (2) sample stability, (3) delay of freezing, (4) volume of storage aliquots, (5) freeze/thaw cycles, (6) thawing conditions, (7) dilution linearity, (8) parallelism, (9) spike recovery, and (10) precision. None of these confounders influenced the levels of α-Synuclein in CSF significantly. We found a very high intra-assay precision. The inter-assay precision was lower than expected due to different performances of kit lots used. Overall the validated immunoassay is useful for the quantification of α-Synuclein in human CSF.

Topics: alpha-Synuclein; Biomarkers; Centrifugation; Enzyme-Linked Immunosorbent Assay; Freezing; Humans; Neurodegenerative Diseases; Observer Variation

Increasingly, evidence argues that many neurodegenerative diseases, including progressive supranuclear palsy (PSP), are caused by prions, which are alternatively folded proteins undergoing self-propagation. In earlier studies, PSP prions were detected by infecting human embryonic kidney (HEK) cells expressing a tau fragment [TauRD(LM)] fused to yellow fluorescent protein (YFP). Here, we report on an improved bioassay using selective precipitation of tau prions from human PSP brain homogenates before infection of the HEK cells. Tau prions were measured by counting the number of cells with TauRD(LM)-YFP aggregates using confocal fluorescence microscopy. In parallel studies, we fused α-synuclein to YFP to bioassay α-synuclein prions in the brains of patients who died of multiple system atrophy (MSA). Previously, MSA prion detection required ∼120 d for transmission into transgenic mice, whereas our cultured cell assay needed only 4 d. Variation in MSA prion levels in four different brain regions from three patients provided evidence for three different MSA prion strains. Attempts to demonstrate α-synuclein prions in brain homogenates from Parkinson's disease patients were unsuccessful, identifying an important biological difference between the two synucleinopathies. Partial purification of tau and α-synuclein prions facilitated measuring the levels of these protein pathogens in human brains. Our studies should facilitate investigations of the pathogenesis of both tau and α-synuclein prion disorders as well as help decipher the basic biology of those prions that attack the CNS.

Topics: alpha-Synuclein; Animals; HEK293 Cells; Humans; Mice; Neurodegenerative Diseases; Prions

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

Abnormal accumulation of amyloid β (Aβ), α-synuclein (α-syn), and microtubule-associated protein tau (tau) have been implicated in neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and Pick's disease (PiD). The mechanisms through which aggregated versions of α-syn, Aβ, and tau may lead to neurodegeneration are not entirely clear, however, there is emerging evidence that neuronal calcium dysregulation is at play. Two-photon microscopy is a powerful tool that can be used to measure in vivo alterations of calcium transients using animal models of neurodegeneration, and when coupled with statistical methods to characterize functional signals, can reveal features that identify and discern between distinct mouse types. We studied four mouse models of neurodegenerative diseases, wild-type (WT) α-syn, E57K α-syn, amyloid precursor protein (APP), and triple-repeat (3R)-Tau and Non-transgenic (tg) littermates using two-photon microscopy. We found that for calcium transients, simple measures such as area under the curve (AUC) and peak width in the 1-Hz whisker pad stimulation paradigm, were significantly increased for WT α-syn, E57K α-syn and APP mice across all cortical depths compared to Non-tg mice. A similar result was found in the 3-Hz paradigm in E57K α-syn mice. Spontaneous calcium transient AUC was significantly higher in WT α-syn mice and lower for APP and 3R Tau mice at 150-μm depth. Going beyond simple measure differences such as group means for AUC, signal peak width, and spontaneous calcium activity counts, we built statistical classifiers to characterize neuronal calcium signals to identify and discern, with quantified measures of confidence, all mouse types. We tested our classifier with FK506, which regulates mitochondrial calcium and found that this drug modulated the WT α-syn calcium transients to such an extent that the classifier easily identified the calcium transients as belonging to Non-tg mice. The coupling of two-photon microscopy data and statistical classifiers serves to effectively create a bioassay where the number of animals and scientific resources can be reduced without compromising the results of the experiment.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Calcineurin Inhibitors; Calcium Signaling; Cluster Analysis; Disease Models, Animal; Female; Mice; Mice, Transgenic; Neurodegenerative Diseases; Physical Stimulation; ROC Curve; Somatosensory Cortex; Tacrolimus; tau Proteins; Vibrissae

Diminished lysosomal function can lead to abnormal cellular accumulation of specific proteins, including α-synuclein, contributing to disease pathogenesis of vulnerable neurons in Parkinson's disease (PD) and related α-synucleinopathies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase (GCase), and mutations in GBA1 are a prominent genetic risk factor for PD. Previous studies showed that in sporadic PD, and in normal aging, GCase brain activity is reduced and levels of corresponding glycolipid substrates are increased. The present study tested whether increasing GCase through AAV-GBA1 intra-cerebral gene delivery in two PD rodent models would reduce the accumulation of α-synuclein and protect midbrain dopamine neurons from α-synuclein-mediated neuronal damage. In the first model, transgenic mice overexpressing wildtype α-synuclein throughout the brain (ASO mice) were used, and in the second model, a rat model of selective dopamine neuron degeneration was induced by AAV-A53T mutant α-synuclein. In ASO mice, intra-cerebral AAV-GBA1 injections into several brain regions increased GCase activity and reduced the accumulation of α-synuclein in the substantia nigra and striatum. In rats, co-injection of AAV-GBA1 with AAV-A53T α-synuclein into the substantia nigra prevented α-synuclein-mediated degeneration of nigrostriatal dopamine neurons by 6 months. These neuroprotective effects were associated with altered protein expression of markers of autophagy. These experiments demonstrate, for the first time, the neuroprotective effects of increasing GCase against dopaminergic neuron degeneration, and support the development of therapeutics targeting GCase or other lysosomal genes to improve neuronal handling of α-synuclein.

Topics: alpha-Synuclein; Animals; Dependovirus; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Female; Genetic Therapy; Genetic Vectors; Glucosylceramidase; Humans; Male; Mesencephalon; Mice, Transgenic; Neurodegenerative Diseases; Rats, Sprague-Dawley

The duration and strength of the dopaminergic signal are regulated by the dopamine transporter (DAT). Drug addiction and neurodegenerative and neuropsychiatric diseases have all been associated with altered DAT activity. The membrane localization and the activity of DAT are regulated by a number of intracellular proteins. α-Synuclein, a protein partner of DAT, is implicated in neurodegenerative disease and drug addiction. Little is known about the regulatory mechanisms of the interaction between DAT and α-synuclein, the cellular location of this interaction, and the functional consequences of this interaction on the basal, amphetamine-induced DAT-mediated dopamine efflux, and membrane microdomain distribution of the transporter. Here, we found that the majority of DAT·α-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane. Further examination of the interaction of DAT and α-synuclein revealed a transient interaction between these two proteins at the plasma membrane. Additionally, we found DAT-induced membrane depolarization enhances plasma membrane localization of α-synuclein, which in turn increases dopamine efflux and enhances DAT localization in cholesterol-rich membrane microdomains.

Topics: alpha-Synuclein; Amphetamine; Animals; Biotinylation; Brain; Cell Line; Cell Membrane; CHO Cells; Cricetinae; Cricetulus; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopaminergic Neurons; Fluorescence Resonance Energy Transfer; Humans; Membrane Microdomains; Neurodegenerative Diseases; Synaptic Transmission; Synucleins

Gene-by-environment interactions are thought to underlie the majority of idiopathic cases of neurodegenerative disease. Recently, we reported that an environmental metabolite extracted from Streptomyces venezuelae increases ROS and damages mitochondria, leading to eventual neurodegeneration of C. elegans dopaminergic neurons. Here we link those data to idiopathic disease models that predict loss of protein handling as a component of disorder progression. We demonstrate that the bacterial metabolite leads to proteostatic disruption in multiple protein-misfolding models and has the potential to synergistically enhance the toxicity of aggregate-prone proteins. Genetically, this metabolite is epistatically regulated by loss-of-function to pink-1, the C. elegans PARK6 homolog responsible for mitochondrial maintenance and autophagy in other animal systems. In addition, the metabolite works through a genetic pathway analogous to loss-of-function in the ubiquitin proteasome system (UPS), which we find is also epistatically regulated by loss of PINK-1 homeostasis. To determine remitting counter agents, we investigated several established antioxidants and found that glutathione (GSH) can significantly protect against metabolite-induced proteostasis disruption. In addition, GSH protects against the toxicity of MG132 and can compensate for the combined loss of both pink-1 and the E3 ligase pdr-1, a Parkin homolog. In assessing the impact of this metabolite on mitochondrial maintenance, we observe that it causes fragmentation of mitochondria that is attenuated by GSH and an initial surge in PINK-1-dependent autophagy. These studies mechanistically advance our understanding of a putative environmental contributor to neurodegeneration and factors influencing in vivo neurotoxicity.

Topics: alpha-Synuclein; Animals; Autophagy; Bacterial Toxins; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Glutathione; Homeostasis; Mitochondria; Neurodegenerative Diseases; Neurons; Proteasome Endopeptidase Complex; Protein Serine-Threonine Kinases; Proteostasis Deficiencies; Streptomyces

Pathology in Parkinson's disease is linked to self-association of α-Synuclein (αS) into pathogenic oligomeric species and highly ordered amyloid fibrils. Developing effective therapeutic strategies against this debilitating disease is critical and βS, a pre-synaptic protein that co-localizes with αS, can act as an inhibitor of αS assembly. Despite the potential importance of βS as an inhibitor of αS, the nature, location and specificity of the molecular interactions between these two proteins is unknown. Here we use NMR paramagnetic relaxation enhancement experiments, to demonstrate that βS interacts directly with αS in a transient dimer complex with high specificity and weak affinity. Inhibition of αS by βS arises from transient αS/βS heterodimer species that exist primarily in head- to- tail configurations while αS aggregation arises from a more heterogeneous and weaker range of transient interactions that include both head-to-head and head-to-tail configurations. Our results highlight that intrinsically disordered proteins can interact directly with one another at low affinity and that the transient interactions that drive inhibition versus aggregation are distinct by virtue of their plasticity and specificity.

Topics: alpha-Synuclein; Amino Acid Sequence; beta-Synuclein; Binding Sites; Models, Biological; Molecular Sequence Data; Neurodegenerative Diseases; Nuclear Magnetic Resonance, Biomolecular; Protein Aggregates; Protein Aggregation, Pathological; Protein Binding; Protein Interaction Domains and Motifs; Protein Interaction Mapping; Protein Multimerization; Protein Transport; Sequence Alignment

Impaired autophagy has been implicated in many neurodegenerative diseases, such as Parkinson's disease (PD), and might be responsible for deposition of aggregated proteins in neurons. However, little is known about how neuronal autophagy and clearance of aggregated proteins are regulated. Here, we show a role for Toll-like receptor 2 (TLR2), a pathogen-recognizing receptor in innate immunity, in regulation of neuronal autophagy and clearance of α-synuclein, a protein aggregated in synucleinopathies, including in PD. Activation of TLR2 resulted in the accumulation of α-synuclein aggregates in neurons as a result of inhibition of autophagic activity through regulation of the AKT/mTOR pathway. In contrast, inactivation of TLR2 resulted in autophagy activation and increased clearance of neuronal α-synuclein, and hence reduced neurodegeneration, in transgenic mice and in in vitro models. These results uncover roles of TLR2 in regulating neuronal autophagy and suggest that the TLR2 pathway may be targeted for autophagy activation strategies in treating neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Autophagy; Mice; Mice, Knockout; Mice, Transgenic; Neurodegenerative Diseases; Oncogene Protein v-akt; Toll-Like Receptor 2; TOR Serine-Threonine Kinases

Topics: Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Brain; Brain Injury, Chronic; DNA-Binding Proteins; Humans; Immunohistochemistry; Neurodegenerative Diseases; Neurofibrillary Tangles; Prevalence; Retrospective Studies; Severity of Illness Index; tau Proteins

Few preclinical studies have assessed the long-term neuropathology and behavioral deficits after sustaining blast-induced neurotrauma (BINT). Previous studies have shown extensive astrogliosis and cell death at acute stages (<7 days) but the temporal response at a chronic stage has yet to be ascertained. Here, we used behavioral assays, immmunohistochemistry and neurochemistry in limbic areas such as the amygdala (Amy), Hippocampus (Hipp), nucleus accumbens (Nac), and prefrontal cortex (PFC), to determine the long-term effects of a single blast exposure. Behavioral results identified elevated avoidance behavior and decreased short-term memory at either one or three months after a single blast event. At three months after BINT, markers for neurodegeneration (FJB) and microglia activation (Iba-1) increased while index of mature neurons (NeuN) significantly decreased in all brain regions examined. Gliosis (GFAP) increased in all regions except the Nac but only PFC was positive for apoptosis (caspase-3). At three months, tau was selectively elevated in the PFC and Hipp whereas α-synuclein transiently increased in the Hipp at one month after blast exposure. The composite neurochemical measure, myo-inositol+glycine/creatine, was consistently increased in each brain region three months following blast. Overall, a single blast event resulted in enduring long-term effects on behavior and neuropathological sequelae.

Topics: alpha-Synuclein; Amygdala; Animals; Apoptosis; Brain Injuries; Caspase 3; Disease Models, Animal; Gliosis; Hippocampus; Male; Memory, Short-Term; Neurodegenerative Diseases; Neurons; Nucleus Accumbens; Prefrontal Cortex; Rats; Rats, Sprague-Dawley

With its traditional use in relieving insomnia and anxiety, our previous study has identified onjisaponin B from Radix Polygalae (RP), as a novel autophagic enhancer with potential neuroprotective effects. In current study, we have further identified a novel active fraction from RP, contains 17 major triterpenoid saponins including the onjisaponin B, by the combinational use of cell membrane chromatography (CMC) and ultra-performance liquid chromatography coupled to (quadrupole) time-of-flight mass spectrometry {UHPLC-(Q)TOF-MS}. By exhibiting more potent autophagic effect in cells, the active fraction enhances the clearance of mutant huntingtin, and reduces protein level and aggregation of α-synuclein in a higher extent when compared with onjisaponin B. Here, we have reported for the first time the new application of cell-based CMC and UHPLC-(Q)TOF-MS analysis in identifying new autophagy inducers with neuroprotective effects from Chinese medicinal herb. This result has provided novel insights into the possible pharmacological actions of the active components present in the newly identified active fraction of RP, which may help to improve the efficacy of the traditional way of prescribing RP, and also provide new standard for the quality control of decoction of RP or its medicinal products in the future.

Topics: alpha-Synuclein; Animals; Autophagy; Cell Membrane; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Huntingtin Protein; Inhibitory Concentration 50; Mice, Knockout; Nerve Tissue Proteins; Neurodegenerative Diseases; Nuclear Proteins; PC12 Cells; Polygala; Proteolysis; Rats; Saponins; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Triterpenes

To investigate histopathology and proteinopathy in the spinal cord of patients with common neurodegenerative diseases.. Spinal cord tissues from clinically and neuropathologically confirmed neruodegnerative diseases were enrolled in this study, including 3 cases of multiple system strophy, 4 cases of amyotrophic lateral sclerosis, 5 cases of Alzheimer's disease (AD, included 2 cases of AD combined with Parkinson's disease), 2 cases of progressive supranuclear palsy, 1 case of dementia with lewy body and 1 case of corticobasal degeneration from 1955 to 2013 at Chinese People's Liberation Army General Hospital. Four normal control cases were also included. Routine HE and Gallyas-Braak staining, and immunohistochemical stainings for anti-PHF tau (AT8), anti-α-synuclein, anti-TDP-43 and anti-ubiquitin were performed.. Examination of the spinal cord in 3 cases with multiple system strophy revealed severe neuron loss in the intermediolateral nucleus of thoracic segment and Onuf's nucleus of the sacral segment, along with moderate neuron loss in the anterior horn of the cervical segment and mild myelin pallor in the anterior funiculus and anterolateral funiculus in the cervical and thoracic segments. Large amount of argentophilic, ubiquitin and synuclein positive oligodendroglial cytoplasmic inclusions were found widely distributed in the anterior horn and the anterior funiculus and anterolateral funiculus of the full spinal cord. Severe neuron loss and several morphological changes with gliosis in the anterior horn and severe loss of myelin in the anterior funiculus and anterolateral funiculus of the full spinal cord were observed in 4 cases of amyotrophic lateral sclerosis, 2 of which were found with Bunina bodies in neurons of the anterior horn. Three amyotrophic lateral sclerosis cases had ubiquitin-positive neuronal inclusions and TDP-43 positive neuronal and glial inclusions in the anterior horn at cervical and lumbar segments. A few argentophilic, tau positive neurofibrillary tangles (NFTs) and neuropil threads in the anterior horn at cervical and lumbar segments were found in 4 AD cases. Examination of spinal cord in 2 cases with Parkinson's disease combined with AD and 1 case with dementia with lewy body revealed severe neuron loss in the intermediolateral nucleus of thoracic segment, and a few synuclein positive lewy bodies and neuritis were also observed. There was mild neuron loss in the anterior horn at cervical and lumbar segments, along with some argentophilic, tau positive globous NFTs and many argentophilic, tau positive neutrophil threads were observed in 2 progressive supranuclear palsy cases and 1 corticobasal degeneration case.. Each common neurodegenerative diseases of the spinal cord including multiple system strophy, amyotrophic lateral sclerosis and Parkinson's disease has its own specific histopathology and proteinopathy characteristics.

Topics: alpha-Synuclein; Alzheimer Disease; Amyotrophic Lateral Sclerosis; DNA-Binding Proteins; Humans; Immunohistochemistry; Inclusion Bodies; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Parkinson Disease; Spinal Cord; Ubiquitin

Cells have developed quality control systems for protection against proteotoxicity. Misfolded and aggregation-prone proteins, which are behind the initiation and progression of many neurodegenerative diseases (ND), are known to challenge the proteostasis network of the cells. We aimed to explore the role of DNJ-27/ERdj5, an endoplasmic reticulum (ER)-resident thioredoxin protein required as a disulfide reductase for the degradation of misfolded proteins, in well-established Caenorhabditis elegans models of Alzheimer, Parkinson and Huntington diseases.. We demonstrate that DNJ-27 is an ER luminal protein and that its expression is induced upon ER stress via IRE-1/XBP-1. When dnj-27 expression is downregulated by RNA interference we find an increase in the aggregation and associated pathological phenotypes (paralysis and motility impairment) caused by human β-amyloid peptide (Aβ), α-synuclein (α-syn) and polyglutamine (polyQ) proteins. In turn, DNJ-27 overexpression ameliorates these deleterious phenotypes. Surprisingly, despite being an ER-resident protein, we show that dnj-27 downregulation alters cytoplasmic protein homeostasis and causes mitochondrial fragmentation. We further demonstrate that DNJ-27 overexpression substantially protects against the mitochondrial fragmentation caused by human Aβ and α-syn peptides in these worm models.. We identify C. elegans dnj-27 as a novel protective gene for the toxicity associated with the expression of human Aβ, α-syn and polyQ proteins, implying a protective role of ERdj5 in Alzheimer, Parkinson and Huntington diseases.. Our data support a scenario where the levels of DNJ-27/ERdj5 in the ER impact cytoplasmic protein homeostasis and the integrity of the mitochondrial network which might underlie its protective effects in models of proteotoxicity associated to human ND.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Autophagy; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Disease Models, Animal; Endoplasmic Reticulum-Associated Degradation; Gene Expression; Gene Expression Regulation; HSP40 Heat-Shock Proteins; Humans; Mitochondria; Molecular Chaperones; Neurodegenerative Diseases; Peptides; Phenotype; Proteasome Endopeptidase Complex; Proteolysis; RNA Interference

NADPH oxidases (NOX), catalyzing the reduction of molecular oxygen to form the superoxide radical anion (•O₂⁻) and hydrogen peroxide (H₂O₂), are involved in several pathological conditions, such as stroke, diabetes, atherosclerosis, but also in chronic neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, or multiple sclerosis. GKT136901 is a novel NOX-1/4 inhibitor with potential application in the areas of diabetic nephropathy, stroke, or neurodegeneration. In the present study, we investigated additional pharmacological activities of the compound with respect to direct free radical scavenging. GKT136901 did not interact with nitric oxide (•NO), •O₂⁻, or hydroxyl radicals (•OH), but it acted as selective scavenger of peroxynitrite (PON) already in the submicromolar concentration range. Alpha synuclein (ASYN) is a protein involved in the pathogenesis of Parkinson's disease and a known target for PON-dependent tyrosine nitration. Submicromolar concentrations of GKT136901 prevented tyrosine nitration and di-tyrosine-dependent dimer formation of ASYN by PON as indicated by Western blot and mass spectrometric analysis. GKT136901 itself was degraded when exposed to PON. In a human neuronal cell model, GKT136901 prevented both the depletion of reduced intracellular glutathione, and the degeneration of neurites when present during PON treatment of the cells. When GKT136901 was applied after PON treatment, no protective effect was observed, thus excluding an impact of GKT136901 on cellular death/survival pathways. In summary, selective scavenging of PON is an additional pharmacological property of the NOX-1/4 inhibitor GKT136901, and this may add to the efficiency of the drug in several disease models.

Topics: alpha-Synuclein; Amino Acid Sequence; Cell Line; Free Radical Scavengers; Humans; Molecular Sequence Data; NADPH Oxidase 1; NADPH Oxidase 4; NADPH Oxidases; Neurodegenerative Diseases; Nitric Oxide; Peroxynitrous Acid; Pyrazoles; Pyridones

Parkinson's disease is a neurodegenerative movement disorder. The histopathology of Parkinson's disease comprises proteinaceous inclusions known as Lewy bodies, which contains aggregated α-synuclein. Cathepsin D (CD) is a lysosomal protease previously demonstrated to cleave α-synuclein and decrease its toxicity in both cell lines and mouse brains in vivo. Here, we show that pharmacological inhibition of CD, or introduction of catalytically inactive mutant CD, resulted in decreased CD activity and increased cathepsin B activity, suggesting a possible compensatory response to inhibition of CD activity. However, this increased cathepsin B activity was not sufficient to maintain α-synuclein degradation, as evidenced by the accumulation of endogenous α-synuclein. Interestingly, the levels of LC3, LAMP1, and LAMP2, proteins involved in autophagy-lysosomal activities, as well as total lysosomal mass as assessed by LysoTracker flow cytometry, were unchanged. Neither autophagic flux nor proteasomal activities differs between cells over-expressing wild-type versus mutant CD. These observations point to a critical regulatory role for that endogenous CD activity in dopaminergic cells in α-synuclein homeostasis which cannot be compensated for by increased Cathepsin B. These data support the potential need to enhance CD function in order to attenuate α-synuclein accumulation as a therapeutic strategy against development of synucleinopathy.

Topics: alpha-Synuclein; Autophagy; Caspases; Cathepsin B; Cathepsin D; Cell Line, Tumor; Gene Expression; Humans; Lentivirus; Lysosomes; Neuroblastoma; Neurodegenerative Diseases; Neurons; Pepstatins; Protease Inhibitors

To study the relationship between neurodegenerative diseases including argyrophilic grain disease (AGD) and late-onset schizophrenia and delusional disorders (LOSD; onset ≥40 years of age), we pathologically examined 23 patients with LOSD, 71 age-matched normal controls, and 22 psychiatric disease controls (11 depression, six personality disorder, two bipolar disorders, and three neurotic disorders cases). In all LOSD cases (compared to age-matched normal controls), the frequencies of Lewy body disease (LBD), AGD, and corticobasal degeneration (CBD) were 26.1 % (11.3 %), 21.7 % (8.5 %), and 4.3 % (0.0 %), respectively. There was no case of pure Alzheimer's disease (AD). The total frequency of LBD, AGD, and CBD was significantly higher in LOSD cases than in normal controls. Argyrophilic grains were significantly more severe in LOSD than in controls, but were almost completely restricted to the limbic system and adjacent temporal cortex. In LOSD patients whose onset occurred at ≥65 years of age (versus age-matched normal controls), the frequencies of LBD and AGD were 36.4 % (19.4 %) and 36.4 % (8.3 %), respectively, and AGD was significantly more frequent in LOSD patients than in normal controls. In LOSD patients whose onset occurred at <65 years of age, the frequencies of LBD, AGD, and CBD were 16.7, 8.3, and 8.3 %, comparable to those of age-matched normal controls (10.2, 5.1, and 0.0 %). In all psychiatric cases, delusion was significantly more frequent in AGD cases than in cases bearing minimal AD pathology alone. Given these findings, LOSD patients may have heterogeneous pathological backgrounds, and AGD may be associated with the occurrence of LOSD especially after 65 years of age.

Topics: Adult; Age of Onset; Aged; Aged, 80 and over; alpha-Synuclein; Brain; Case-Control Studies; DNA-Binding Proteins; Female; Humans; Intermediate Filaments; Male; Middle Aged; Neurodegenerative Diseases; Psychotic Disorders; Schizophrenia; Statistics, Nonparametric; tau Proteins

Topics: alpha-Synuclein; Animals; Benzimidazoles; Cytoprotection; Endosomal Sorting Complexes Required for Transport; Female; Gene Regulatory Networks; Humans; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Parkinson Disease; Saccharomyces cerevisiae Proteins; Ubiquitin-Protein Ligase Complexes; Ubiquitin-Protein Ligases

The development of molecular descriptions of intrinsically disordered proteins (IDPs) is essential for elucidating conformational transitions that characterize common neurodegenerative disorders. We use nuclear magnetic resonance, small angle scattering, and molecular ensemble approaches to characterize the IDPs Tau and α-synuclein. Ensemble descriptions of IDPs are highly underdetermined due to the inherently large number of degrees of conformational freedom compared with available experimental measurements. Using extensive cross-validation we show that five different types of independent experimental parameters are predicted more accurately by selected ensembles than by statistical coil descriptions. The improvement increases in regions whose local sampling deviates from statistical coil, validating the derived conformational description. Using these approaches we identify enhanced polyproline II sampling in aggregation-nucleation sites, supporting suggestions that this region of conformational space is important for aggregation.

Topics: Algorithms; alpha-Synuclein; Humans; Intrinsically Disordered Proteins; Magnetic Resonance Spectroscopy; Membrane Proteins; Neurodegenerative Diseases; Proline; Protein Folding; Protein Structure, Tertiary; Scattering, Radiation

α-Synuclein aggregation is central to the pathogenesis of several brain disorders. However, the native conformations and functions of this protein in the human brain are not precisely known. The native state of α-synuclein was probed by gel filtration coupled with native gradient gel separation, an array of antibodies with non-overlapping epitopes, and mass spectrometry. The existence of metastable conformers and stable monomer was revealed in the human brain.

Topics: alpha-Synuclein; Brain; Chromatography, Gel; Epitope Mapping; Epitopes; Humans; Hydrogen Bonding; Mass Spectrometry; Neurodegenerative Diseases; Parkinson Disease; Protein Binding; Protein Folding; Protein Structure, Tertiary; Sucrose; Ultracentrifugation

ATP6V0C is the bafilomycin A1-binding subunit of vacuolar ATPase, an enzyme complex that critically regulates vesicular acidification. We and others have shown previously that bafilomycin A1 regulates cell viability, autophagic flux and metabolism of proteins that accumulate in neurodegenerative disease. To determine the importance of ATP6V0C for autophagy-lysosome pathway function, SH-SY5Y human neuroblastoma cells differentiated to a neuronal phenotype were nucleofected with non-target or ATP6V0C siRNA and following recovery were treated with either vehicle or bafilomycin A1 (0.3-100 nM) for 48 h. ATP6V0C knockdown was validated by quantitative RT-PCR and by a significant decrease in Lysostracker Red staining. ATP6V0C knockdown significantly increased basal levels of microtubule-associated protein light chain 3-II (LC3-II), α-synuclein high molecular weight species and APP C-terminal fragments, and inhibited autophagic flux. Enhanced LC3 and LAMP-1 co-localization following knockdown suggests that autophagic flux was inhibited in part due to lysosomal degradation and not by a block in vesicular fusion. Knockdown of ATP6V0C also sensitized cells to the accumulation of autophagy substrates and a reduction in neurite length following treatment with 1 nM bafilomycin A1, a concentration that did not produce such alterations in non-target control cells. Reduced neurite length and the percentage of propidium iodide-positive dead cells were also significantly greater following treatment with 3 nM bafilomycin A1. Together these results indicate a role for ATP6V0C in maintaining constitutive and stress-induced ALP function, in particular the metabolism of substrates that accumulate in age-related neurodegenerative disease and may contribute to disease pathogenesis.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Autophagy; Cell Line, Tumor; Humans; Lysosomal Membrane Proteins; Lysosomes; Microtubule-Associated Proteins; Neuroblastoma; Neurodegenerative Diseases; Vacuolar Proton-Translocating ATPases

Pathological accumulation of intermediate filaments can be observed in neurodegenerative disorders, such as Alzheimer's disease, frontotemporal dementia and Parkinson's disease, and is also characteristic of neuronal intermediate filament inclusion disease. Intermediate filaments type IV include three neurofilament proteins (light, medium and heavy molecular weight neurofilament subunits) and α-internexin. The phosphorylation of intermediate filament proteins contributes to axonal growth, and is regulated by protein kinase A. Here we describe a family with a novel late-onset neurodegenerative disorder presenting with dementia and/or parkinsonism in 12 affected individuals. The disorder is characterized by a unique neuropathological phenotype displaying abundant neuronal inclusions by haematoxylin and eosin staining throughout the brain with immunoreactivity for intermediate filaments. Combining linkage analysis, exome sequencing and proteomics analysis, we identified a heterozygous c.149T>G (p.Leu50Arg) missense mutation in the gene encoding the protein kinase A type I-beta regulatory subunit (PRKAR1B). The pathogenicity of the mutation is supported by segregation in the family, absence in variant databases, and the specific accumulation of PRKAR1B in the inclusions in our cases associated with a specific biochemical pattern of PRKAR1B. Screening of PRKAR1B in 138 patients with Parkinson's disease and 56 patients with frontotemporal dementia did not identify additional novel pathogenic mutations. Our findings link a pathogenic PRKAR1B mutation to a novel hereditary neurodegenerative disorder and suggest an altered protein kinase A function through a reduced binding of the regulatory subunit to the A-kinase anchoring protein and the catalytic subunit of protein kinase A, which might result in subcellular dislocalization of the catalytic subunit and hyperphosphorylation of intermediate filaments.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Cyclic AMP-Dependent Protein Kinase Catalytic Subunits; Cyclic AMP-Dependent Protein Kinase RIbeta Subunit; DNA-Binding Proteins; Electron Microscope Tomography; Family Health; Female; Frontal Lobe; Genetic Association Studies; Humans; Male; Middle Aged; Models, Molecular; Nerve Tissue Proteins; Neurodegenerative Diseases; Polymorphism, Single Nucleotide; tau Proteins

Misfolded protein aggregates, characterized by a canonical amyloid fold, play a central role in the pathobiology of neurodegenerative diseases. Agents that bind and sequester neurotoxic intermediates of amyloid assembly, inhibit the assembly or promote the destabilization of such protein aggregates are in clinical testing. Here, we show that the gene 3 protein (g3p) of filamentous bacteriophage mediates potent generic binding to the amyloid fold. We have characterized the amyloid binding and conformational remodeling activities using an array of techniques, including X-ray fiber diffraction and NMR. The mechanism for g3p binding with amyloid appears to reflect its physiological role during infection of Escherichia coli, which is dependent on temperature-sensitive interdomain unfolding and cis-trans prolyl isomerization of g3p. In addition, a natural receptor for g3p, TolA-C, competitively interferes with Aβ binding to g3p. NMR studies show that g3p binding to Aβ fibers is predominantly through middle and C-terminal residues of the Aβ subunit, indicating β strand-g3p interactions. A recombinant bivalent g3p molecule, an immunoglobulin Fc (Ig) fusion of the two N-terminal g3p domains, (1) potently binds Aβ fibers (fAβ) (KD=9.4nM); (2); blocks fAβ assembly (IC50~50nM) and (3) dissociates fAβ (EC50=40-100nM). The binding of g3p to misfolded protein assemblies is generic, and amyloid-targeted activities can be demonstrated using other misfolded protein systems. Taken together, our studies show that g3p(N1N2) acts as a general amyloid interaction motif.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Bacterial Outer Membrane Proteins; Bacteriophage M13; Capsid Proteins; Escherichia coli Proteins; Humans; Kinetics; Membrane Transport Proteins; Models, Molecular; Neurodegenerative Diseases; Protein Binding; Protein Conformation; Protein Folding; Protein Interaction Domains and Motifs; Protein Multimerization; Recombinant Fusion Proteins; tau Proteins

Missense mutations in the leucine-rich repeat kinase 2 (LRRK2) gene can cause late-onset Parkinson disease. Past studies have provided conflicting evidence for the protective effects of LRRK2 knockdown in models of Parkinson disease as well as other disorders. These discrepancies may be caused by uncertainty in the pathobiological mechanisms of LRRK2 action. Previously, we found that LRRK2 knockdown inhibited proinflammatory responses from cultured microglia cells. Here, we report LRRK2 knockout rats as resistant to dopaminergic neurodegeneration elicited by intracranial administration of LPS. Such resistance to dopaminergic neurodegeneration correlated with reduced proinflammatory myeloid cells recruited in the brain. Additionally, adeno-associated virus-mediated transduction of human α-synuclein also resulted in dopaminergic neurodegeneration in wild-type rats. In contrast, LRRK2 knockout animals had no significant loss of neurons and had reduced numbers of activated myeloid cells in the substantia nigra. Although LRRK2 expression in the wild-type rat midbrain remained undetected under nonpathological conditions, LRRK2 became highly expressed in inducible nitric oxide synthase (iNOS)-positive myeloid cells in the substantia nigra in response to α-synuclein overexpression or LPS exposures. Our data suggest that knocking down LRRK2 may protect from overt cell loss by inhibiting the recruitment of chronically activated proinflammatory myeloid cells. These results may provide value in the translation of LRRK2-targeting therapeutics to conditions where neuroinflammation may underlie aspects of neuronal dysfunction and degeneration.

Topics: alpha-Synuclein; Animals; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lipopolysaccharides; Myeloid Cells; Neurodegenerative Diseases; Nitric Oxide Synthase Type II; Protein Serine-Threonine Kinases; Rats; Rats, Transgenic; Substantia Nigra

Loss-of-function mutations in the PINK1 gene lead to recessive forms of Parkinson's disease. Animal models with depleted PINK1 expression have failed to reproduce significant nigral dopaminergic neurodegeneration and clear alpha-synuclein pathology, main characteristics of the disease. In this study, we investigated whether alpha-synuclein pathology is altered in the absence of PINK1 in cell culture and in vivo. We observed that downregulation of PINK1 enhanced alpha-synuclein aggregation and apoptosis in a neuronal cell culture model for synucleinopathy. Silencing of PINK1 expression in mouse substantia nigra using recombinant adeno-associated viral vectors did not induce dopaminergic neurodegeneration in a long-term study up to 10 months, nor did it enhance or accelerate dopaminergic neurodegeneration after alpha-synuclein overexpression. However, in PINK1 knockout mice, overexpression of alpha-synuclein in the substantia nigra resulted in enhanced dopaminergic neurodegeneration as well as significantly higher levels of alpha-synuclein phosphorylation at serine 129 at 4 weeks postinjection. In conclusion, our results demonstrate that total loss of PINK1 leads to an increased sensitivity to alpha-synuclein-induced neuropathology and cell death in vivo.

Topics: alpha-Synuclein; Animals; Apoptosis; Cells, Cultured; Disease Progression; Down-Regulation; Gene Expression; Humans; Mice, Knockout; Mutation; Neurodegenerative Diseases; Neurons; Parkinson Disease; Phosphorylation; Protein Aggregates; Protein Aggregation, Pathological; Protein Kinases; Substantia Nigra

Drosophila melanogaster has contributed significantly to the understanding of disease mechanisms in Parkinson's disease (PD) as it is one of the very few PD model organisms that allow the study of age-dependent behavioral defects, physiology and histology, and genetic interactions among different PD-related genes. However, there have been contradictory results from a number of recent reports regarding the loss of dopaminergic neurons in different PD fly models. In an attempt to re-evaluate and clarify this issue, we have examined three different genetic (α-synuclein, Pink1, parkin) and two toxin-based (rotenone and paraquat) models of the disease for neuronal cell loss. Our results showed no dopaminergic neuronal loss in all models tested. Despite this surprising result, we found additional phenotypes showing the dysfunctional status of the dopaminergic neurons in most of the models analyzed. A common feature found in most models is a quantifiable decrease in the fluorescence of a green-fluorescent protein reporter gene in dopaminergic neurons that correlates well with other phenotypes found for these models and can be reliably used as a hallmark of the neurodegenerative process when modeling diseases affecting the dopaminergic system in Drosophila. Analyzing three genetic and two toxin-based Drosophila models of Parkinson's disease (PD) through green fluorescent protein reporter and α-tyrosine hydroxylase staining, we have found the number of dopaminergic neurons to remain unchanged. Despite the lack of neuronal loss, we have detected a remarkable decrease in a reporter green-fluorescent protein (GFP) signal in dopaminergic neurons, suggesting an abnormal neuronal status that correlates with the phenotypes associated with those PD fly models.

Topics: alpha-Synuclein; Animals; Cell Count; Dopaminergic Neurons; Drosophila; Drosophila Proteins; Mutation; Neurodegenerative Diseases; Parkinson Disease; Parkinson Disease, Secondary; Protein Serine-Threonine Kinases; Signal Transduction; Ubiquitin-Protein Ligases

Protein misfolding is implicated in numerous lethal neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and Parkinson disease (PD). There are no therapies that reverse these protein-misfolding events. We aim to apply Hsp104, a hexameric AAA+ protein from yeast, to target misfolded conformers for reactivation. Hsp104 solubilizes disordered aggregates and amyloid, but has limited activity against human neurodegenerative disease proteins. Thus, we have previously engineered potentiated Hsp104 variants that suppress aggregation, proteotoxicity and restore proper protein localization of ALS and PD proteins in Saccharomyces cerevisiae, and mitigate neurodegeneration in an animal PD model. Here, we establish that potentiated Hsp104 variants possess broad substrate specificity and, in yeast, suppress toxicity and aggregation induced by wild-type TDP-43, FUS and α-synuclein, as well as missense mutant versions of these proteins that cause neurodegenerative disease. Potentiated Hsp104 variants also rescue toxicity and aggregation of TAF15 but not EWSR1, two RNA-binding proteins with a prion-like domain that are connected with the development of ALS and frontotemporal dementia. Thus, potentiated Hsp104 variants are not entirely non-specific. Indeed, they do not unfold just any natively folded protein. Rather, potentiated Hsp104 variants are finely tuned to unfold proteins bearing short unstructured tracts that are not recognized by wild-type Hsp104. Our studies establish the broad utility of potentiated Hsp104 variants.

Topics: alpha-Synuclein; Heat-Shock Proteins; Mutation; Neurodegenerative Diseases; Saccharomyces cerevisiae Proteins

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

Several neurodegenerative diseases are classified as proteopathies as they are associated with the aggregation of misfolded proteins. Synucleinopathies are a group of neurodegenerative disorders associated with abnormal deposition of synucleins. α-Synucleinopathies include Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Recently accumulation of another member of the synuclein family- γ-synuclein in neurodegenerative diseases compelled the introduction of the term γ-synucleinopathy. The formation of aggregates and deposits of γ-synuclein is facilitated after its oxidation at methionine 38 (Met38).. Several types of intracytoplasmic inclusions containing post-translationally modified α- and γ-synucleins are detected. Oxidized Met38-γ-synuclein forms aberrant inclusions in amygdala and substantia nigra. Double staining revealed colocalization of oxidized-γ-synuclein with α-synuclein in the cytoplasm of neurons. Another type of synuclein positive inclusions in the amygdala of dementia with Lewy bodies patients has the appearance of Lewy bodies. These inclusions are immunoreactive when analyzed with antibodies to α-synuclein phosphorylated on serine 129, as well as with antibodies to oxidized-γ-synuclein. Some of these Lewy bodies have doughnut-like shape with round or elongated shape. The separate immunofluorescent images obtained with individual antibodies specific to oxidized-γ-synuclein and phospho-α-synuclein clearly shows the colocalization of these synuclein isoforms in substantia nigra inclusions. Phospho-α-synuclein is present almost exclusively at the periphery of these structures, whereas oxidized-γ-syn immunoreactivity is also located in the internal parts forming dot-like pattern of staining.. These results reveal new γ-synuclein positive lesions in human brain. Oxidized-γ-synuclein is colocalized with phospho-α-synuclein in doughnut-like inclusions. Several types of astrocytes with different morphology are immunopositive for oxidized-γ-synuclein.

Topics: alpha-Synuclein; Amygdala; Antibodies; Astrocytes; gamma-Synuclein; Humans; Neoplasm Proteins; Neurodegenerative Diseases; Neurons; Phosphorylation; Substantia Nigra

Pathological changes in corticobasal degeneration (CBD) consist of abnormal deposition of the microtubule-associated protein tau. However, the simultaneous accumulation of different misfolded proteins in the brain can be observed in many neurodegenerative diseases with significantly longer disease durations. We encountered a patient with CBD who survived for an extremely long period (18 years) after the diagnosis. We performed an autopsy to elucidate the effect of the longer survival on the pathology of CBD. We observed abnormal aggregation of trans-activating response region DNA-binding protein of 43 kDa (TDP-43) and α-synuclein, as well as phosphorylated tau, in neurons of broader regions of the brain, beyond the amygdala and other limbic areas. We found that phosphorylated tau, α-synuclein, and TDP-43 partially co-existed in the same cellular aggregates. The triple pathologic changes might be related to the longer survival of the patient compared with the typical clinical course of patients with CBD. Further investigations are required to support the hypothesis that tauopathy, synucleinopathy, and TDP-43 proteinopathy might share common pathogenic mechanisms in terms of cross-seeding of the pathologic proteins.

Topics: Aged; alpha-Synuclein; Cerebral Cortex; DNA-Binding Proteins; Fatal Outcome; Humans; Male; Neurodegenerative Diseases

Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, is characterized by the degeneration of dopamine (DA) neurons and age-dependent formation of protein inclusions that contain the α-synuclein (α-syn) protein. RNA interference (RNAi) screening using Caenorhabditis elegans identified RTCB-1, an uncharacterized gene product, as one of several significant modifiers of α-syn protein misfolding. RTCB-1 is the worm ortholog of the human HSPC117 protein, a component of RNA trafficking granules in mammalian neurons. Here we show that RTCB-1 protects C. elegans DA neurons from age-dependent degeneration induced by human α-syn. Moreover, neuronal-specific RNAi depletion of rtcb-1 enhanced α-syn-induced degeneration. Similar results were obtained when worms were exposed to the DA neurotoxin 6-hydroxydopamine. HSPC117 has been characterized recently as an essential subunit of the human tRNA splicing ligase complex. tRNA ligases have alternative functions in RNA repair and nonconventional mRNA splicing events. For example, in yeast, unconventional splicing of HAC1, a transcription factor that controls the unfolded protein response (UPR), is mediated by a tRNA ligase. In C. elegans, we demonstrate that RTCB-1 is necessary for xbp-1 (worm homolog of HAC1) mRNA splicing. Moreover, using a RNA ligase-dead mutant, we determine that the ligase activity of worm RTCB-1 is required for its neuroprotective role, which, in turn, is mediated through XBP-1 in the UPR pathway. Collectively, these studies highlight the mechanistic intersection of RNA processing and proteostasis in mediating neuroprotection.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Carrier Proteins; Humans; Neurodegenerative Diseases; Proteins; RNA Splicing; Unfolded Protein Response

Deficient peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) function is one component of mitochondrial dysfunction in neurodegenerative diseases. Current molecular classification of such diseases is based on the predominant protein accumulating as intra- or extracellular aggregates. Experimental evidence suggests that mitochondrial dysfunction and impaired protein processing are closely interrelated. In vitro findings further indicate that PGC-1α dysfunction may contribute to protein misfolding in neurodegeneration.. To systematically evaluate the neuropathological alterations of mice lacking the expression of the full-length PGC-1α protein (FL-PGC-1α) but expressing an N-truncated fragment.. To assess the pattern of neurodegeneration-related proteins, we performed immunostaining for Tau, pTau, α-synuclein, amyloid-β, amyloid precursor protein, prion protein, FUS, TDP-43 and ubiquitin. Using hematoxylin and eosin, Klüver-Barrera and Bielschowsky silver stainings and anti-GFAP immunohistochemistry, we performed an anatomical mapping to provide a lesion profile.. The immunohistochemical pattern of neurodegeneration-related proteins did not differ between FL-PGC-1α knockout and wild-type animals, and there was a complete lack of protein deposits or ubiquitin-positive inclusions. The analysis of neuropathological alterations revealed widespread vacuolation predominating in the cerebral white matter, caudate-putamen, thalamus and brainstem, and reactive astrogliosis in the brainstem and cerebellar nuclei. This morphological phenotype was thus reminiscent of human mitochondrial encephalopathies, especially the Kearns-Sayre syndrome.. We conclude that the lack of FL-PGC-1α per se is insufficient to recapitulate major features of neurodegenerative diseases, but evokes a pathology seen in mitochondrial encephalopathies, which makes PGC-1α-deficient mice a valuable model for this yet incurable group of diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; DNA-Binding Proteins; Female; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondrial Encephalomyopathies; Neurodegenerative Diseases; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Prions; RNA-Binding Protein FUS; Silver Staining; tau Proteins; Transcription Factors; Ubiquitin

Protein aggregates are a common feature of neurodegenerative syndromes. Specific protein fragments were found to be aggregated in disorders including Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease. Here, we show that the natural C-terminal fragments of Tau, TDP43, and α-synuclein are short-lived substrates of the Arg/N-end rule pathway, a processive proteolytic system that targets proteins bearing "destabilizing" N-terminal residues. Furthermore, a natural TDP43 fragment is shown to be metabolically stabilized in Ate1(-/-) fibroblasts that lack the arginylation branch of the Arg/N-end rule pathway, leading to accumulation and aggregation of this fragment. We also found that a fraction of Aβ42, the Alzheimer's disease-associated fragment of APP, is N-terminally arginylated in the brains of 5xFAD mice and is degraded by the Arg/N-end rule pathway. The discovery that neurodegeneration-associated natural fragments of TDP43, Tau, α-synuclein, and APP can be selectively destroyed by the Arg/N-end rule pathway suggests that this pathway counteracts neurodegeneration.

Topics: alpha-Synuclein; Amino Acid Sequence; Amyloid beta-Protein Precursor; Animals; Arginine; Brain; Calpain; Cell Extracts; DNA-Binding Proteins; Frontotemporal Lobar Degeneration; Half-Life; HEK293 Cells; Humans; Matrix Metalloproteinase 3; Mice; Mice, Transgenic; Molecular Sequence Data; Neurodegenerative Diseases; NIH 3T3 Cells; Peptide Fragments; Protein Stability; Proteolysis; Reticulocytes; Saccharomyces cerevisiae; tau Proteins

Several epidemiological studies suggest that pesticides could lead to neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. Among pesticides, insecticides appear more neurotoxic than others but the neurotoxic mechanisms leading to adverse health effects remain unclear. The currently used pesticides such as rotenone and paraquat could disrupt mitochondrial bioenergetic function, reactive oxygen metabolism, redox function and promote α-synuclein aggregation. In addition, recent studies demonstrate that genetic susceptibility to Parkinson's disease could monitor pesticide susceptibility, as demonstrated for polymorphisms in pesticide metabolizing enzymes that are involved in organophosphorus sensitivity.

Topics: alpha-Synuclein; Alzheimer Disease; Animals; Genetic Predisposition to Disease; Humans; Insecticides; Mitochondria; Neurodegenerative Diseases; Paraquat; Parkinson Disease; Parkinson Disease, Secondary; Pesticides; Rotenone

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Prion Diseases; Proteostasis Deficiencies; PrPC Proteins; tau Proteins

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the fly as an experimental system include its genetic tractability, short life span and the possibility to observe and quantitatively analyze complex behaviors. The expression of disease-linked genes in specific neuronal populations of the Drosophila brain, can be used to model human neurodegenerative diseases such as Parkinson's and Alzheimer's (5). Dopaminergic (DA) neurons are among the most vulnerable neuronal populations in the aging human brain. In Parkinson's disease (PD), the most common neurodegenerative movement disorder, the accelerated loss of DA neurons leads to a progressive and irreversible decline in locomotor function. In addition to age and exposure to environmental toxins, loss of DA neurons is exacerbated by specific mutations in the coding or promoter regions of several genes. The identification of such PD-associated alleles provides the experimental basis for the use of Drosophila as a model to study neurodegeneration of DA neurons in vivo. For example, the expression of the PD-linked human α-synuclein gene in Drosophila DA neurons recapitulates some features of the human disease, e.g. progressive loss of DA neurons and declining locomotor function (2). Accordingly, this model has been successfully used to identify potential therapeutic targets in PD (8). Here we describe two assays that have commonly been used to study age-dependent neurodegeneration of DA neurons in Drosophila: a climbing assay based on the startle-induced negative geotaxis response and tyrosine hydroxylase immunostaining of whole adult brain mounts to monitor the number of DA neurons at different ages. In both cases, in vivo expression of UAS transgenes specifically in DA neurons can be achieved by using a tyrosine hydroxylase (TH) promoter-Gal4 driver line (3, 10).

Topics: alpha-Synuclein; Animals; Brain; Dopaminergic Neurons; Drosophila melanogaster; Female; Fluorescent Antibody Technique; Humans; Male; Neurodegenerative Diseases; Phenotype; Tyrosine 3-Monooxygenase

This experiment assessed normative expression patterns of alpha-synuclein (SYNC), including ganglionic remodeling and development of SYNC pathologies, in the submucosal plexus (SMP) of the colon during healthy aging. The observations address age-associated changes in bowel function and are relevant to evaluations of SMP-containing colonic biopsies for SYNC or synucleinopathies associated with aging and peripheral neurodegenerative diseases.. Colonic submucosal whole mounts from groups of virgin male Fischer 344 rats (n ≥ 8 per group) at 4, 8, 16, and 24 months of age were processed immunohistochemically for SYNC and the pan-neuronal marker HuC/D. In addition, macrophages immunoreactive for MHCII were examined. Stereological protocols were used to generate unbiased estimates of neuron density, neurons per ganglion, neurons per ganglionic area, and neuron size.. The protein SYNC was expressed in a subpopulation of SMP neurons, in both nucleus and cytoplasm. The general age-associated pattern across different cell counts was an increase in the number of SYNC+ neurons between 4 and 8 months of age, with progressively decreasing numbers of both SYNC+ and SYNC- neurons over the remaining lifespan. The soma size of SYNC+ neurons increased progressively with age. Aggregated SYNC occurred in the aging SMP, and macrophages with alternatively activated profiles were located adjacent to pathological SYNC deposits, consistent with ongoing phagocytosis.. Changes in SYNC expression with age, including a baseline of accumulating synucleinopathies in the healthy aging SMP, need to be considered when interpreting either functional disturbances or biopsies of the aging colon.

Topics: Aging; alpha-Synuclein; Animals; Biopsy; Colon; Immunohistochemistry; Male; Neurodegenerative Diseases; Rats; Rats, Inbred F344; Submucous Plexus

Microglia are resident immunosurveillant cells in the central nervous system, and astrocytes are important for blood flow, plasticity, and neurotransmitter regulation. The aim of this study was to investigate whether astrocyte and microglial activation, estimated through markers in cerebrospinal fluid and serum, differed between synucleinopathies, tauopathies, and controls.. We analyzed the glial activation markers YKL-40 and soluble CD14 in serum and cerebrospinal fluid from 37 controls, 50 patients with Parkinson's disease (PD), and 79 P+ patients (those with progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy).. Cerebrospinal fluid levels of YKL-40 were decreased significantly in patients who had PD compared with controls (P < 0.05), patients who had multiple system atrophy (P < 0.01), and patients who had tauopathies (P < 0.0001). In addition, cerebrospinal fluid levels of YKL-40 were significantly lower in patients who had synucleinopathies than in those who had tauopathies (P < 0.0001).. The decreased cerebrospinal fluid levels of YKL-40 suggest that glial activation is reduced in the brains of patients who have Parkinson's disease and synucleinopathies compared with patients who have tauopathies and controls.

Topics: Adipokines; Aged; alpha-Synuclein; Analysis of Variance; Basal Ganglia Diseases; Chitinase-3-Like Protein 1; Female; Humans; Lectins; Lipopolysaccharide Receptors; Male; Middle Aged; Multiple System Atrophy; Neurodegenerative Diseases; Parkinson Disease; Supranuclear Palsy, Progressive; Tauopathies

Topics: alpha-Synuclein; Humans; Neurodegenerative Diseases; Tauopathies

Rapid eye movement sleep behavior disorder (RBD) is an early feature in α synucleinopathies and may precede other clinical manifestations of disease for several years. Olfactory dysfunction and mild motor abnormalities (MMAs) are highly prevalent in prodromal α synucleinopathies such as RBD and are suspected to be predictive neurodegenerative markers. Because both markers also are highly prevalent in the healthy elderly population, the discriminative value to detect an early neurodegenerative process is unclear.. We examined 28 patients with idiopathic RBD (iRBD) without manifest neurodegenerative disease to determine diagnostic accuracy of MMAs and olfactory dysfunction in identifying patients with early nigrostriatal degeneration in transcranial sonography (TCS) and (123)I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane single-photon emission computed tomography ((123)I-FP-CIT-SPECT).. Sixty-three percent of our participants showed MMAs which were strongly associated with abnormal TCS and (123)I-FP-CIT-SPECT findings. The discriminative value in detecting participants with early nigrostriatal degeneration was excellent (area under the receiver operating characteristic [ROC] curve, 0.84 [P≤.003] for TCS and 0.79 [P≤.066] for (123)I-FP-CIT-SPECT). Olfactory dysfunction was present in 78% of iRBD participants, but it was not linked with neuroimaging abnormalities or MMAs. Olfactory dysfunction did not discriminate participants with early nigrostriatal degeneration (area under the ROC curve, 0.54 [P≤.747] for TCS and 0.31 [P≤.225] for (123)I-FP-CIT-SPECT). Early RBD manifestation but no demographic (e.g., age, gender) or clinical characteristics of RBD (e.g., duration, severity of RBD) were associated with neuroimaging abnormalities in TCS and (123)I-FP-CIT-SPECT.. Unlike olfactory dysfunction, MMAs discriminate patients with early nigrostriatal degeneration in iRBD. Early RBD manifestation seems to be an additional risk factor which aggravates neurodegenerative risk.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Corpus Striatum; Early Diagnosis; Female; Humans; Male; Middle Aged; Movement Disorders; Neurodegenerative Diseases; Olfaction Disorders; Prevalence; REM Sleep Behavior Disorder; Risk Factors; Substantia Nigra; Tomography, Emission-Computed, Single-Photon; Ultrasonography, Doppler, Transcranial

Human genetics has indicated a causal role for the protein α-synuclein in the pathogenesis of familial Parkinson's disease (PD), and the aggregation of synuclein in essentially all patients with PD suggests a central role for this protein in the sporadic disorder. Indeed, the accumulation of misfolded α-synuclein now defines multiple forms of neural degeneration. Like many of the proteins that accumulate in other neurodegenerative disorders, however, the normal function of synuclein remains poorly understood. In this article, we review the role of synuclein at the nerve terminal and in membrane remodeling. We also consider the prion-like propagation of misfolded synuclein as a mechanism for the spread of degeneration through the neuraxis.

Topics: alpha-Synuclein; Animals; Humans; Neurodegenerative Diseases; Parkinson Disease; Prions

α-Synuclein (α-syn) is a small lipid-binding protein implicated in several neurodegenerative diseases, including Parkinson's disease, whose pathobiology is conserved from yeast to man. There are no therapies targeting these underlying cellular pathologies, or indeed those of any major neurodegenerative disease. Using unbiased phenotypic screens as an alternative to target-based approaches, we discovered an N-aryl benzimidazole (NAB) that strongly and selectively protected diverse cell types from α-syn toxicity. Three chemical genetic screens in wild-type yeast cells established that NAB promoted endosomal transport events dependent on the E3 ubiquitin ligase Rsp5/Nedd4. These same steps were perturbed by α-syn itself. Thus, NAB identifies a druggable node in the biology of α-syn that can correct multiple aspects of its underlying pathology, including dysfunctional endosomal and endoplasmic reticulum-to-Golgi vesicle trafficking.

Topics: alpha-Synuclein; Animals; Benzimidazoles; Caenorhabditis elegans; Cells, Cultured; Cytoprotection; Drug Evaluation, Preclinical; Endosomal Sorting Complexes Required for Transport; Gene Regulatory Networks; Nedd4 Ubiquitin Protein Ligases; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Parkinson Disease; Rats; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Small Molecule Libraries; Ubiquitin-Protein Ligase Complexes; Ubiquitin-Protein Ligases

Emerging evidence indicates important protective roles being played by autophagy in neurodegenerative disorders through clearance of aggregate-prone or mutant proteins. In the current study, we aimed to identify autophagy inducers from Chinese medicinal herbs as a potential neuroprotective agent that enhances the clearance of mutant huntingtin and α-synuclein in PC-12 cells. Through intensive screening using the green fluorescent protein-light chain 3 (GFP-LC3) autophagy detection platform, we found that the ethanol extracts of Radix Polygalae (Yuan Zhi) were capable of inducing autophagy. Further investigation showed that among three single components derived from Radix Polygalae--i.e., polygalacic acid, senegenin and onjisaponin B--onjisaponin B was able to induce autophagy and accelerate both the removal of mutant huntingtin and A53T α-synuclein, which are highly associated with Huntington disease and Parkinson disease, respectively. Our study further demonstrated that onjisaponin B induces autophagy via the AMPK-mTOR signaling pathway. Therefore, findings in the current study provide detailed insights into the protective mechanism of a novel autophagy inducer, which is valuable for further investigation as a new candidate agent for modulating neurodegenerative disorders through the reduction of toxicity and clearance of mutant proteins in the cellular level.

Topics: alpha-Synuclein; Animals; Autophagy; Cell Line; Drugs, Chinese Herbal; Humans; Huntingtin Protein; Huntington Disease; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Proteolysis; Rats; Saponins; Signal Transduction; Triterpenes

Neurodegenerative diseases such as Alzheimer (AD) and Parkinson (PD) are characterized by abnormal aggregation of misfolded β-sheet-rich proteins, including amyloid-β (Aβ)-derived peptides and tau in AD and α-synuclein in PD. Correct folding and assembly of these proteins are controlled by ubiquitously expressed molecular chaperones; however, our understanding of neuron-specific chaperones and their involvement in the pathogenesis of neurodegenerative diseases is limited. We here describe novel chaperone-like functions for the secretory protein 7B2, which is widely expressed in neuronal and endocrine tissues. In in vitro experiments, 7B2 efficiently prevented fibrillation and formation of Aβ(1-42), Aβ(1-40), and α-synuclein aggregates at a molar ratio of 1:10. In cell culture experiments, inclusion of recombinant 7B2, either in the medium of Neuro-2A cells or intracellularly via adenoviral 7B2 overexpression, blocked the neurocytotoxic effect of Aβ(1-42) and significantly increased cell viability. Conversely, knockdown of 7B2 by RNAi increased Aβ(1-42)-induced cytotoxicity. In the brains of APP/PSEN1 mice, a model of AD amyloidosis, immunoreactive 7B2 co-localized with aggregation-prone proteins and their respective aggregates. Furthermore, in the hippocampus and substantia nigra of human AD- and PD-affected brains, 7B2 was highly co-localized with Aβ plaques and α-synuclein deposits, strongly suggesting physiological association. Our data provide insight into novel functions of 7B2 and establish this neural protein as an anti-aggregation chaperone associated with neurodegenerative disease.

Topics: Aged; alpha-Synuclein; Amino Acid Sequence; Amyloid beta-Peptides; Animals; Cell Death; Female; Hippocampus; Humans; Immunohistochemistry; Mice; Mice, Transgenic; Microscopy, Electron, Transmission; Molecular Sequence Data; Neurodegenerative Diseases; Neuroendocrine Secretory Protein 7B2; Substantia Nigra

Aggregation of α-synuclein (α-syn) in the brain is a defining pathological feature of neurodegenerative disorders classified as synucleinopathies. They include Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Occupational and environmental exposure to manganese (Mn) is associated with a neurological syndrome consisting of psychiatric symptoms, cognitive impairment and parkinsonism. In this study, we examined α-syn immunoreactivity in the frontal cortex of Cynomolgus macaques as part of a multidisciplinary assessment of the neurological effects produced by exposure to moderate levels of Mn. We found increased α-syn-positive cells in the gray matter of Mn-exposed animals, typically observed in pyramidal and medium-sized neurons in deep cortical layers. Some of these neurons displayed loss of Nissl staining with α-syn-positive spherical aggregates. In the white matter we also observed α-syn-positive glial cells and in some cases α-syn-positive neurites. These findings suggest that Mn exposure promotes α-syn aggregation in neuronal and glial cells that may ultimately lead to degeneration in the frontal cortex gray and white matter. To our knowledge, this is the first report of Mn-induced neuronal and glial cell α-syn accumulation and aggregation in the frontal cortex of non-human primates.

Topics: alpha-Synuclein; Animals; Frontal Lobe; Immunohistochemistry; Macaca fascicularis; Male; Manganese; Neurodegenerative Diseases

Increasing evidence indicates that RNA plays an active role in a number of neurodegenerative diseases. We recently introduced a theoretical framework, catRAPID, to predict the binding ability of protein and RNA molecules. Here, we use catRAPID to investigate ribonucleoprotein interactions linked to inherited intellectual disability, amyotrophic lateral sclerosis, Creutzfeuld-Jakob, Alzheimer's, and Parkinson's diseases. We specifically focus on (1) RNA interactions with fragile X mental retardation protein FMRP; (2) protein sequestration caused by CGG repeats; (3) noncoding transcripts regulated by TAR DNA-binding protein 43 TDP-43; (4) autogenous regulation of TDP-43 and FMRP; (5) iron-mediated expression of amyloid precursor protein APP and α-synuclein; (6) interactions between prions and RNA aptamers. Our results are in striking agreement with experimental evidence and provide new insights in processes associated with neuronal function and misfunction.

Topics: Algorithms; alpha-Synuclein; Amyloid beta-Protein Precursor; Aptamers, Nucleotide; DNA-Binding Proteins; Female; Fragile X Mental Retardation Protein; Fragile X Syndrome; Gene Expression Regulation; Humans; Male; Models, Theoretical; Neurodegenerative Diseases; Prions; Protein Binding; Ribonucleoproteins; RNA; RNA-Binding Proteins; RNA, Untranslated

Parkinson's disease (PD) is pathologically characterized by the presence of α-synuclein positive intracytoplasmic inclusions. The missense mutation, A53T α-synuclein is closely related to hereditary, early-onset PD. Accumulating evidences suggest that pathological accumulation of A53T α-synuclein protein will perturb itself to be efficiently and normally degraded through its usual degradation pathway, macroautophagy-lysosome pathway, therefore toxic effects on the neuron will be exacerbated. Based on the above fact, we demonstrated in this study that A53T α-synuclein overexpression impairs macroautophagy in SH-SY5Y cells and upregulates mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase (p70S6K) signaling, the classical suppressive pathway of autophagy. We further found that curcumin, a natural compound derived from the curry spice turmeric and with low toxicity in normal cells, could efficiently reduce the accumulation of A53T α-synuclein through downregulation of the mTOR/p70S6K signaling and recovery of macroautophagy which was suppressed. These findings suggested that the regulation of mTOR/p70S6K signaling may be a participant of the accumulation of A53T α-synuclein protein-linked Parkinsonism. Meanwhile curcumin could be a candidate neuroprotective agent by inducing macroautophagy, and needs to be further investigated by clinical application in patients suffering Parkinson's disease.

Topics: Adenine; alpha-Synuclein; Autophagy; Blotting, Western; Cell Line; Cell Survival; Curcumin; Genetic Vectors; Humans; Immunohistochemistry; Macrophages; Neurodegenerative Diseases; Neuroprotective Agents; Parkinson Disease; Ribosomal Protein S6 Kinases, 70-kDa; TOR Serine-Threonine Kinases; Transfection

α-Synuclein is an abundant presynaptic protein and a primary component of Lewy bodies in Parkinson disease. Although its pathogenic role remains unclear, in healthy nerve terminals α-synuclein undergoes a cycle of membrane binding and dissociation. An α-synuclein binding assay was used to screen for vesicle proteins involved in α-synuclein membrane interactions and showed that antibodies directed to the Ras-related GTPase Rab3a and its chaperone RabGDI abrogated α-synuclein membrane binding. Biochemical analyses, including density gradient sedimentation and co-immunoprecipitation, suggested that α-synuclein interacts with membrane-associated GTP-bound Rab3a but not to cytosolic GDP-Rab3a. Accumulation of membrane-bound α-synuclein was induced by the expression of a GTPase-deficient Rab3a mutant, by a dominant-negative GDP dissociation inhibitor mutant unable to recycle Rab3a off membranes, and by Hsp90 inhibitors, radicicol and geldanamycin, which are known to inhibit Rab3a dissociation from membranes. Thus, all treatments that inhibited Rab3a recycling also increased α-synuclein sequestration on intracellular membranes. Our results suggest that membrane-bound GTP-Rab3a stabilizes α-synuclein on synaptic vesicles and that the GDP dissociation inhibitor·Hsp90 complex that controls Rab3a membrane dissociation also regulates α-synuclein dissociation during synaptic activity.

Topics: alpha-Synuclein; Animals; Brain; Cell Line, Tumor; Cell Membrane; Cytosol; Epitopes; Glycerol; Guanosine Triphosphate; HSP90 Heat-Shock Proteins; Humans; Mice; Mice, Transgenic; Models, Biological; Neurodegenerative Diseases; Neurons; rab3A GTP-Binding Protein; Subcellular Fractions; Synapses; Synaptosomes

Several studies revealed consistent overlap between synucleinopathies and tauopathies, demonstrating that α-synuclein (ASYN) and tau co-localize in neurofibrillary tangles and in Lewy bodies from Alzheimer's and Parkinson's disease patients and corresponding animal models. Additionally, it has been shown that ASYN can act as an initiator of tau aggregation and phosphorylation and that these two proteins directly interact. Despite these evidences, the cellular pathway implicated in this synergistic interaction remains to be clarified. The aim of this study was to create a yeast model where the concomitant expression of ASYN and tau can be used to perform genome wide screenings for the identification of genes that modulate this interaction, in order to shed light into the pathological mechanism of cell dysfunction and to provide new targets for future therapeutic intervention. We started by validating the synergistic toxicity of tau and ASYN co-expression in yeast, by developing episomal and integrative strains expressing WT and mutant forms of both proteins, alone or in combination. The episomal strains showed no differences in growth delay upon expression of ASYN isoforms (WT or A53T) alone or in combination with tau 2N/4R isoforms (WT or P301L). However, in these strains, the presence of ASYN led to increased tau insolubility and correlated with increased tau phosphorylation in S396/404, which is mainly mediated by RIM11, the human homolog of GSK3β in yeast. On the other hand, the integrative strains showed a strong synergistic toxic effect upon co-expression of ASYN WT and tau WT, which was related to high levels of intracellular ASYN inclusions and increased tau phosphorylation and aggregation. Taken together, the strains described in the present study are able to mimic relevant pathogenic features involved in neurodegeneration and are powerful tools to identify potential target genes able to modulate the synergistic pathway driven by ASYN and tau interaction.

Topics: alpha-Synuclein; Neurodegenerative Diseases; Protein Binding; tau Proteins

Vitamin A has been characterized as a potential neurotoxin, because ingestion of such vitamin - or its derivatives, the retinoids - at moderate to high doses elicits a myriad of deleterious effects, from acute intoxication involving head-ache, confusion, and 'pseudo tumor cerebri' to chronic, and perhaps irreversible, abnormalities, including irritability, anxiety, depression, and suicide ideation. Nevertheless, it still remains to be found the mechanism by which vitamin A induces cognitive decline. Based on the fact that vitamin A at clinical doses is a potent pro-oxidant agent to the central nervous system, we performed the present work to analyze whether a cotreatment with L-NAME at 30 mg/kg (four times a week) was able to prevent (or minimize) the biochemical and/or behavioral disturbances resulting from a 28-day daily supplementation with retinol palmitate at doses from 1000 to 9000 IU/kg/day. Then, we investigated mitochondrial function, redox parameters, and the levels of proteins potentially involved in neurodegenerative events, as for instance α-synuclein and receptor for advanced glycation endproducts. Besides, monoamine oxidase enzyme activity was quantified in this work. We observed that L-NAME cotreatment was not completely effective in preventing the redox disturbances induced by vitamin A supplementation. Moreover, L-NAME cotreatment did not affect the behavioral deficits elicited by vitamin A supplementation. We conclude that other parameters rather than NO levels or its derivatives, as for example ONOO(-), take a more important role in mediating the negative effects triggered by vitamin A supplementation.

Topics: alpha-Synuclein; Animals; Anxiety Disorders; Behavior, Animal; Central Nervous System; Dietary Supplements; Diterpenes; Electron Transport; Glutathione Transferase; Heat-Shock Proteins; Illness Behavior; Locomotion; Male; Manganese; Mitochondria; Monoamine Oxidase; Neurodegenerative Diseases; NG-Nitroarginine Methyl Ester; Nitric Oxide; Oxidation-Reduction; Rats; Rats, Wistar; Receptor for Advanced Glycation End Products; Receptors, Dopamine; Receptors, Immunologic; Retinyl Esters; Superoxide Dismutase; Superoxides; Tyrosine; Vitamin A

Intracellular deposition of fibrillar aggregates of α-synuclein (αSyn) characterizes neurodegenerative diseases such as Parkinson's disease (PD) and dementia with Lewy bodies. However, recent evidence indicates that small αSyn oligomeric aggregates that precede fibril formation may be the most neurotoxic species and can be found extracellularly. This new evidence has changed the view of pathological αSyn aggregation from a self-contained cellular phenomenon to an extracellular event and prompted investigation of the putative effects of extracellular αSyn oligomers. In this study, we report that extracellular application of αSyn oligomers detrimentally impacts neuronal welfare and memory function. We found that oligomeric αSyn increased intracellular Ca(2+) levels, induced calcineurin (CaN) activity, decreased cAMP response element-binding protein (CREB) transcriptional activity and resulted in calcineurin-dependent death of human neuroblastoma cells. Similarly, CaN induction and CREB inhibition were observed when αSyn oligomers were applied to organotypic brain slices, which opposed hippocampal long-term potentiation. Furthermore, αSyn oligomers induced CaN, inhibited CREB and evoked memory impairments in mice that received acute intracerebroventricular injections. Notably, all these events were reversed by pharmacological inhibition of CaN. Moreover, we found decreased active CaN and reduced levels of phosphorylated CREB in autopsy brain tissue from patients affected by dementia with Lewy bodies, which is characterized by deposition of αSyn aggregates and progressive cognitive decline. These results indicate that exogenously applied αSyn oligomers impact neuronal function and produce memory deficits through mechanisms that involve CaN activation.

Topics: Aged; Aged, 80 and over; Alkaline Phosphatase; alpha-Synuclein; Analysis of Variance; Animals; Biophysics; Calcineurin; Calcium; Cell Line, Tumor; Conditioning, Psychological; Disease Models, Animal; Drug Administration Routes; Electric Stimulation; Fear; Female; Hippocampus; Humans; In Vitro Techniques; L-Lactate Dehydrogenase; Long-Term Potentiation; Male; Memory Disorders; Mice; Mice, Inbred C57BL; Neuroblastoma; Neurodegenerative Diseases; Neurons; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Transfection

Fibrillar αSynuclein is the major constituent of Lewy bodies and Lewy neurites, the protein deposits characteristic for Parkinson's disease (PD). Multiplications of the αSynuclein gene, as well as point mutations cause familial PD. However, the exact role of αSynuclein in neurodegeneration remains uncertain. Recent research in invertebrates has suggested that oligomeric rather than fibrillizing αSynuclein mediates neurotoxicity. To investigate the impact of αSynuclein aggregation on the progression of neurodegeneration, we expressed variants with different fibrillation propensities in the rat substantia nigra (SN) by means of recombinant adeno-associated viral (AAV) vectors. The formation of proteinase K-resistant αSynuclein aggregates was correlated to the loss of nigral dopaminergic (DA) neurons and striatal fibers. Expression of two prefibrillar, structure-based design mutants of αSynuclein (i.e., A56P and A30P/A56P/A76P) resulted in less aggregate formation in nigral DA neurons as compared to human wild-type (WT) or the inherited A30P mutation. However, only the αSynuclein variants capable of forming fibrils (WT/A30P), but not the oligomeric αSynuclein species induced a sustained progressive loss of adult nigral DA neurons. These results demonstrate that divergent modes of αSynuclein neurotoxicity exist in invertebrate and mammalian DA neurons in vivo and suggest that fibrillation of αSynuclein promotes the progressive degeneration of nigral DA neurons as found in PD patients.

Topics: Age Factors; alpha-Synuclein; Analysis of Variance; Animals; Cells, Cultured; Disease Models, Animal; Dopaminergic Neurons; Gene Expression Regulation; Genetic Vectors; Green Fluorescent Proteins; Humans; Mutation; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Protein Kinases; Rats; Substantia Nigra; Transduction, Genetic; Transfection; Tyrosine 3-Monooxygenase; Vesicular Monoamine Transport Proteins

Parkinson's disease (PD) is characterised by the progressive loss of nigral dopamine neurons and the presence of synucleinopathy. Overexpression of α-synuclein in vivo using viral vectors has opened interesting possibilities to model PD-like pathology in rodents. However, the attempts made so far have failed to show a consistent behavioural phenotype and pronounced dopamine neurodegeneration. Using a more efficient adeno-associated viral (AAV) vector construct, which includes a WPRE enhancer element and uses the neuron-specific synapsin-1 promoter to drive the expression of human wild-type α-synuclein, we have now been able to achieve increased levels of α-synuclein in the transduced midbrain dopamine neurons sufficient to induce profound deficits in motor function, accompanied by reduced expression of proteins involved in dopamine neurotransmission and a time-dependent loss of nigral dopamine neurons, that develop progressively over 2-4 months after vector injection. As in human PD, nigral cell loss was preceded by degenerative changes in striatal axons and terminals, and the appearance of α-synuclein positive inclusions in dystrophic axons and dendrites, supporting the idea that α-synuclein-induced pathology hits the axons and terminals first and later progresses to involve also the cell bodies. The time-course of changes seen in the AAV-α-synuclein treated animals defines distinct stages of disease progression that matches the pre-symptomatic, early symptomatic, and advanced stages seen in PD patients. This model provides new interesting possibilities for studies of stage-specific pathologic mechanisms and identification of targets for disease-modifying therapeutic interventions linked to early or late stages of the disease.

Topics: alpha-Synuclein; Amphetamine; Analysis of Variance; Animals; Antiparkinson Agents; Behavioral Symptoms; Cell Count; Chromatography, High Pressure Liquid; Dependovirus; Disease Models, Animal; Disease Progression; Dopamine; Dopaminergic Neurons; ELAV Proteins; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression Regulation; Genetic Vectors; Green Fluorescent Proteins; Humans; Levodopa; Mesencephalon; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Rats; Rats, Sprague-Dawley; Regulatory Elements, Transcriptional; Stereotyped Behavior; Time Factors; Tyrosine 3-Monooxygenase; Vesicular Monoamine Transport Proteins

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

We have previously shown that persistent α-synuclein overexpression in ventral midbrain of marmoset leads to a distinctive neurodegenerative process and motor defects. The neurodegeneration was confined to caudate putamen dopaminergic fibers in animals overexpressing wild-type (wt) α-synuclein. However, A53T α-synuclein overexpression induced neurodegeneration that resulted in nigral dopaminergic cell death. Here, we analyze the microglia population in the midbrain of these animals by stereological quantification of Iba1+ cells. Our data here show that monkeys overexpressing A53T α-synuclein showed a long-term increase in microglia presenting macrophagic morphology. However, wt α-synuclein overexpression, despite the absence of dopaminergic cell death, resulted in a permanent robust increase of the microglia population characterized by a range of distinct morphological types that persisted after 1 year. These results confirm that the microglial response differs depending on the type of α-synuclein (wt/A53T) and/or whether α-synuclein expression results in cell death or not, suggesting that microglia may play different roles during disease progression. Furthermore, the microglial response is modulated by events related to α-synuclein expression in substantia nigra and persists in the long term. The data presented here is in agreement with that previously observed in a recombinant adeno-associated virus (rAAV) α-synuclein rat model, thereby validating both the findings and the model, and highlighting the translational potential of the rodent model to higher species closer to humans.

Topics: alpha-Synuclein; Animals; Callithrix; Caudate Nucleus; Cell Count; Cell Death; Cell Polarity; Dependovirus; Dopaminergic Neurons; Female; Genetic Vectors; Gliosis; HLA-DR Antigens; Immunohistochemistry; Macrophage Activation; Male; Mesencephalon; Microglia; Mutation; Neurodegenerative Diseases; Parkinson Disease, Secondary; Pluripotent Stem Cells; Presynaptic Terminals; Putamen

Mutations in the genes encoding LRRK2 and α-synuclein cause autosomal dominant forms of familial Parkinson's disease (PD). Fibrillar forms of α-synuclein are a major component of Lewy bodies, the intracytoplasmic proteinaceous inclusions that are a pathological hallmark of idiopathic and certain familial forms of PD. LRRK2 mutations cause late-onset familial PD with a clinical, neurochemical and, for the most part, neuropathological phenotype that is indistinguishable from idiopathic PD. Importantly, α-synuclein-positive Lewy bodies are the most common pathology identified in the brains of PD subjects harboring LRRK2 mutations. These observations may suggest that LRRK2 functions in a common pathway with α-synuclein to regulate its aggregation. To explore the potential pathophysiological interaction between LRRK2 and α-synuclein in vivo, we modulated LRRK2 expression in a well-established human A53T α-synuclein transgenic mouse model with transgene expression driven by the hindbrain-selective prion protein promoter. Deletion of LRRK2 or overexpression of human G2019S-LRRK2 has minimal impact on the lethal neurodegenerative phenotype that develops in A53T α-synuclein transgenic mice, including premature lethality, pre-symptomatic behavioral deficits and human α-synuclein or glial neuropathology. We also find that endogenous or human LRRK2 and A53T α-synuclein do not interact together to influence the number of nigrostriatal dopaminergic neurons. Taken together, our data suggest that α-synuclein-related pathology, which occurs predominantly in the hindbrain of this A53T α-synuclein mouse model, occurs largely independently from LRRK2 expression. These observations fail to provide support for a pathophysiological interaction of LRRK2 and α-synuclein in vivo, at least within neurons of the mouse hindbrain.

Topics: alpha-Synuclein; Animals; Brain; Disease Models, Animal; Humans; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lewy Bodies; Mice; Mice, Knockout; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Phenotype; Protein Serine-Threonine Kinases

Topics: alpha-Synuclein; Biomarkers; Humans; Immunoassay; Neurodegenerative Diseases; Parkinson Disease; Phosphoproteins

In neurodegenerative diseases, it remains unclear why certain brain regions are selectively vulnerable to protein aggregation. In transgenic mice expressing human A53T α-synuclein, the brainstem and spinal cord develop the most prominent α-synuclein inclusions which correlate with age-dependent motor dysfunction. Herein we present the novel finding that this selective aggregation is in part dependent on the inability of chaperone-mediated autophagy (CMA) to effectively degrade α-synuclein in these brain regions. Lysosomal assays revealed that CMA activity was significantly decreased in aggregation-prone regions compared to the remainder of the brain. Previously, CMA activity has been shown to be proportional to levels of the CMA receptor Lamp-2a. Using antibodies, brain tissue from Lamp-2a null mice, enzymatic deglycosylation, and mass spectrometry, we identified Lamp2a as a novel 72kDa glycoprotein in the mouse brain. Examination of Lamp-2a levels revealed differences in expression across brain regions. The brainstem and the spinal cord had a more than three-fold greater levels of Lamp-2a as compared to regions less vulnerable to aggregation and exhibited a selective upregulation of Lamp-2a during development of α-synuclein inclusions. Despite this dynamic response of Lamp-2a, the levels of substrates bound to the brain lysosomes as well as the rates of substrate uptake and degradation were not proportional to the levels of Lamp-2a. These regional differences in CMA activity and Lamp-2a expression were found in both non-transgenic mice as well as A53T α-syn mice. Therefore, these are inherent variations and not a transgene-specific effect. However, differences in CMA activity may render select brain regions vulnerable to homeostatic dysfunction in the presence of stressors such as overexpression of human A53T α-syn. Collectively, the data provide a potential mechanism to explain the dichotomy of vulnerability or resistance that underlies brain regions during aggregate formation in neurodegenerative disease.

Topics: alpha-Synuclein; Animals; Autophagy; Blotting, Western; Brain; Brain Chemistry; Brain Stem; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Inclusion Bodies; Lysosomal-Associated Membrane Protein 2; Lysosomes; Mice; Mice, Transgenic; Molecular Chaperones; Movement Disorders; Neurodegenerative Diseases; Polymerase Chain Reaction; RNA; Spinal Cord

Macroautophagy is a dynamic process whereby cytoplasmic components are initially sequestered within autophagosomes. Recent studies have shown that the autophagosome membrane can selectively recognize ubiquitinated proteins and organelles through interaction with adapter proteins such as p62 and NBR1. Both proteins are structurally similar at the amino acid level, and bind with ubiquitin and ubiquitinated proteins. Although p62 is incorporated into a wide spectrum of pathological inclusions in various neurodegenerative diseases, abnormalities of NBR1 have not been reported in these diseases. Our immunohistochemical examination revealed that the vast majority of Lewy bodies (LBs) in Parkinson's disease and dementia with LBs (DLB) as well as of glial cytoplasmic inclusions in multiple system atrophy (MSA) were positive for NBR1. Neuronal and glial inclusions in tauopathies and TAR DNA-binding protein of 43 kDa proteinopathies were rarely immunolabeled, or were unstained. Using cultured cells bearing LB-like inclusions, formation of α-synuclein aggregates was repressed in cells with NBR1 knockdown. Immunoblot analysis showed that the level of NBR1 was significantly increased by 2.5-fold in MSA, but not in DLB. These findings suggest that NBR1 is involved in the formation of cytoplasmic inclusions in α-synucleinopathy.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Autophagy; Brain; Female; Humans; Immunohistochemistry; Inclusion Bodies; Intracellular Signaling Peptides and Proteins; Lewy Bodies; Male; Middle Aged; Neurodegenerative Diseases; Neuroglia; Neurons; Proteins

Multiple system atrophy (MSA) is a progressive late onset neurodegenerative α-synucleinopathy with unclear pathogenesis. Recent genetic and pathological studies support a central role of α-synuclein (αSYN) in MSA pathogenesis. Oligodendroglial cytoplasmic inclusions of fibrillar αSYN and dysfunction of the ubiquitin-proteasome system are suggestive of proteolytic stress in this disorder. To address the possible pathogenic role of oligodendroglial αSYN accumulation and proteolytic failure in MSA we applied systemic proteasome inhibition (PSI) in transgenic mice with oligodendroglial human αSYN expression and determined the presence of MSA-like neurodegeneration in this model as compared to wild-type mice. PSI induced open field motor disability in transgenic αSYN mice but not in wild-type mice. The motor phenotype corresponded to progressive and selective neuronal loss in the striatonigral and olivopontocerebellar systems of PSI-treated transgenic αSYN mice. In contrast no neurodegeneration was detected in PSI-treated wild-type controls. PSI treatment of transgenic αSYN mice was associated with significant ultrastructural alterations including accumulation of fibrillar human αSYN in the cytoplasm of oligodendroglia, which resulted in myelin disruption and demyelination characterized by increased g-ratio. The oligodendroglial and myelin pathology was accompanied by axonal degeneration evidenced by signs of mitochondrial stress and dysfunctional axonal transport in the affected neurites. In summary, we provide new evidence supporting a primary role of proteolytic failure and suggesting a neurodegenerative pathomechanism related to disturbed oligodendroglial/myelin trophic support in the pathogenesis of MSA.

Topics: 2',3'-Cyclic-Nucleotide Phosphodiesterases; alpha-Synuclein; Analysis of Variance; Animals; Autophagy; Brain; Dopamine and cAMP-Regulated Phosphoprotein 32; Exploratory Behavior; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Immunoelectron; Motor Activity; Myelin Proteolipid Protein; Neurodegenerative Diseases; Oligodendroglia; Oligopeptides; Proteasome Endopeptidase Complex; Time Factors; Tyrosine 3-Monooxygenase; Ubiquitin

Parkinson disease (PD) is one of the most common age-related neurodegenerative diseases associated with motor deficiencies in humans. The symptoms are caused by the death of dopaminergic neurons in the brain, which is accompanied by the misfolding and aggregation of the protein α-synuclein. Diagnosis is based on the incidence of clinical symptoms, although they only appear as a result of the irreversible damage of neurons during the disease. Identification of a suitable biomarker would allow preclinical diagnosis. We an approach to quantify single α-synuclein aggregates as a possible biomarker for PD.

Topics: alpha-Synuclein; Benzothiazoles; Biomarkers; Circular Dichroism; Dopaminergic Neurons; Fluorescent Dyes; Humans; Hydrogen-Ion Concentration; Microscopy, Electron, Transmission; Microscopy, Fluorescence; Models, Biological; Neurodegenerative Diseases; Parkinson Disease; Recombinant Proteins; Surface Properties; Temperature; Thiazoles

Amyloidogenic neurodegenerative diseases are incurable conditions with high social impact that are typically caused by specific, largely disordered proteins. However, the underlying molecular mechanism remains elusive to established techniques. A favored hypothesis postulates that a critical conformational change in the monomer (an ideal therapeutic target) in these "neurotoxic proteins" triggers the pathogenic cascade. We use force spectroscopy and a novel methodology for unequivocal single-molecule identification to demonstrate a rich conformational polymorphism in the monomer of four representative neurotoxic proteins. This polymorphism strongly correlates with amyloidogenesis and neurotoxicity: it is absent in a fibrillization-incompetent mutant, favored by familial-disease mutations and diminished by a surprisingly promiscuous inhibitor of the critical monomeric β-conformational change, neurotoxicity, and neurodegeneration. Hence, we postulate that specific mechanostable conformers are the cause of these diseases, representing important new early-diagnostic and therapeutic targets. The demonstrated ability to inhibit the conformational heterogeneity of these proteins by a single pharmacological agent reveals common features in the monomer and suggests a common pathway to diagnose, prevent, halt, or reverse multiple neurodegenerative diseases.

Topics: alpha-Synuclein; Amino Acid Sequence; Amyloidogenic Proteins; Animals; Biomechanical Phenomena; Carrier Proteins; Cloning, Molecular; Humans; Molecular Sequence Data; Nanotechnology; Nephelometry and Turbidimetry; Neurodegenerative Diseases; Neurotoxins; Peptide Termination Factors; Plasmids; Polyproteins; Protein Engineering; Protein Stability; Protein Structure, Secondary; Protein Unfolding; Rats; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Spectrum Analysis; Thermodynamics; Vesicle-Associated Membrane Protein 2

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

Fibrillar amyloid-like deposits and co-deposits of tau and α-synuclein are found in several common neurodegenerative diseases. Recent evidence indicates that small oligomers are the most relevant toxic aggregate species. While tau fibril formation is well-characterized, factors influencing tau oligomerization and molecular interactions of tau and α-synuclein are not well understood.. We used a novel approach applying confocal single-particle fluorescence to investigate the influence of tau phosphorylation and metal ions on tau oligomer formation and its coaggregation with α-synuclein at the level of individual oligomers. We show that Al3+ at physiologically relevant concentrations and tau phosphorylation by GSK-3β exert synergistic effects on the formation of a distinct SDS-resistant tau oligomer species even at nanomolar protein concentration. Moreover, tau phosphorylation and Al3+ as well as Fe3+ enhanced both formation of mixed oligomers and recruitment of α-synuclein in pre-formed tau oligomers.. Our findings provide a new perspective on interactions of tau phosphorylation, metal ions, and the formation of potentially toxic oligomer species, and elucidate molecular crosstalks between different aggregation pathways involved in neurodegeneration.

Topics: alpha-Synuclein; Cell Line, Tumor; Escherichia coli; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Iron; Metals; Neurodegenerative Diseases; Phosphorylation; Protein Multimerization; Solvents; tau Proteins

Familial Parkinson disease (PD) can result from α-synuclein gene multiplication, implicating the reduction of neuronal α-synuclein as a therapeutic target. Moreover, α-synuclein content in human cerebrospinal fluid (CSF) represents a PD biomarker candidate. However, capture-based assays for α-synuclein quantification in CSF (such as by ELISA) have shown discrepancies and have limited suitability for high-throughput screening. Here, we describe two sensitive, in-solution, time-resolved Förster's resonance energy transfer (TR-FRET)-based immunoassays for total and oligomeric α-synuclein quantification. CSF analysis showed strong concordance for total α-synuclein content between two TR-FRET assays and, in agreement with a previously characterized 36 h protocol-based ELISA, demonstrated lower α-synuclein levels in PD donors. Critically, the assay suitability for high-throughput screening of siRNA constructs and small molecules aimed at reducing endogenous α-synuclein levels was established and validated. In a small-scale proof of concept compound screen using 384 well plates, signals ranged from <30 to >120% of the mean of vehicle-treated cells for molecules known to lower and increase cellular α-synuclein, respectively. Furthermore, a reverse genetic screen of a kinase-directed siRNA library identified seven genes that modulated α-synuclein protein levels (five whose knockdown increased and two that decreased cellular α-synuclein protein). This provides critical new biological insight into cellular pathways regulating α-synuclein steady-state expression that may help guide further drug discovery efforts. Moreover, we describe an inherent limitation in current α-synuclein oligomer detection methodology, a finding that will direct improvement of future assay design. Our one-step TR-FRET-based platform for α-synuclein quantification provides a novel platform with superior performance parameters for the rapid screening of large biomarker cohorts and of compound and genetic libraries, both of which are essential to the development of PD therapies.

Topics: alpha-Synuclein; Animals; Antibodies; Biochemistry; Biomarkers; Cohort Studies; Drug Design; Female; Fluorescence Resonance Energy Transfer; Gene Expression Regulation; Gene Library; Humans; Immunoassay; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Parkinson Disease; RNA, Small Interfering

The intracellular deposition of misfolded proteins is a common neuropathological hallmark of most neurodegenerative disorders. Increasing evidence suggests that these pathogenic proteins may spread to neighboring cells and induce the propagation of neurodegeneration.. In this study, we have demonstrated that α-synuclein (αSYN), a major constituent of intracellular inclusions in synucleinopathies, was taken up by neuronal and oligodendroglial cells in both a time- and concentration-dependent manner. Once incorporated, the extracellular αSYN was immediately assembled into high-molecular-weight oligomers and subsequently formed cytoplasmic inclusion bodies. Furthermore, αSYN uptake by neurons and cells of the oligodendroglial lineage was markedly decreased by the genetic suppression and pharmacological inhibition of the dynamin GTPases, suggesting the involvement of the endocytic pathway in this process.. Our findings shed light on the mode of αSYN uptake by neuronal and oligodendroglial cells and identify therapeutic strategies aimed at reducing the propagation of protein misfolding.

Topics: alpha-Synuclein; Animals; Blotting, Western; Cell Line; Coculture Techniques; Dynamins; Endocytosis; Enzyme Inhibitors; Fluorescent Antibody Technique; Humans; Inclusion Bodies; Mice; Microscopy, Confocal; Neurodegenerative Diseases; Neurons; Oligodendroglia

To assess the ability of 5 cerebrospinal fluid(CSF) biomarkers to differentiate between common dementia and parkinsonian disorders.. A cross-sectional, clinic-based study.. Cerebrospinal fluid samples (N=453) were obtained from healthy individuals serving as controls and from patients with Parkinson disease (PD), PD with dementia(PDD), dementia with Lewy bodies (DLB), Alzheimer disease (AD), progressive supranuclear palsy(PSP), multiple system atrophy (MSA), or corticobasal degeneration (CBD).. Neurology and memory disorder clinics.. Cerebrospinal fluid biomarker levels in relation to clinical diagnosis.. Cerebrospinal fluid levels of -synuclein were decreased in patients with PD, PDD, DLB, and MSA but increased in patients with AD. Cerebrospinal fluid levels of α-amyloid 1-42 were decreased in DLB and even further decreased in AD. Cerebrospinal fluid levels of total tau and hyperphosphorylated tau were increased in AD. Multivariate analysis revealed that these biomarkers could differentiate AD from DLB and PDD with an area under the curve of 0.90, with -synuclein and total tau contributing most to the model. Cerebrospinal fluid levels of neurofilament light chain were substantially increased in atypical parkinsonian disorders (ie, PSP, MSA,and CBD), and multivariate analysis revealed that the level of neurofilament light chain alone could differentiate PD from atypical parkinsonian disorders, with an area under the curve of 0.93.. Ascertainment of the -synuclein level in CSF somewhat improves the differential diagnosis of AD vs DLB and PDD when combined with established AD biomarkers.The level of neurofilament light chain alone may differentiate PD from atypical parkinsonian disorders.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Cross-Sectional Studies; Dementia; Diagnosis, Differential; Enzyme-Linked Immunosorbent Assay; Female; Hemoglobins; Humans; Male; Middle Aged; Multiple System Atrophy; Neurodegenerative Diseases; Neuropsychological Tests; Parkinson Disease; Psychiatric Status Rating Scales; Severity of Illness Index; Statistics, Nonparametric; Supranuclear Palsy, Progressive; tau Proteins

Charged multivesicular body protein 2B (CHMP2B) is a component of the endosomal sorting complex required for transport-III, which is involved in the degradation of proteins in the endocytic and autophagic pathways. Mutations in the CHMP2B gene cause frontotemporal dementia and amyotrophic lateral sclerosis characterized by accumulation of ubiquitinated protein aggregates. Recent studies have shown that autophagosomal proteins are present in α-synuclein aggregates in neurons and glial cells in Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). We therefore immunohistochemically examined the brains of various neurodegenerative diseases using CHMP2B-specific antibody. CHMP2B immunoreactivity was present in intracytoplasmic and axonal Lewy bodies in PD and DLB as well as in neuronal and glial cytoplasmic inclusions in MSA. No CHMP2B immunoreactivity was found in a variety of other neuronal and glial inclusions in TDP-43 proteinopathy and tauopathy. These findings suggest that endosomal and autophagic pathway is associated with degradation or formation of α-synuclein aggregates in α-synucleinopathy.

Topics: alpha-Synuclein; Brain; Cadaver; Endosomal Sorting Complexes Required for Transport; Humans; Inclusion Bodies; Lewy Bodies; Neurodegenerative Diseases; Neuroglia; Tissue Distribution

Several human diseases including neurodegenerative disorders and cancer are associated with abnormal accumulation and aggregation of misfolded proteins. Proteins with high tendency to aggregate include the p53 gene product, TAU and alpha synuclein. The potential toxicity of aberrantly folded proteins is limited via their transport into intracellular sub-compartments, the aggresomes, where misfolded proteins are stored or cleared via autophagy. We have identified a region of the acetyltransferase p300 that is highly disordered and displays similarities with prion-like domains. We show that this region is encoded as an alternative spliced variant independently of the acetyltransferase domain, and provides an interaction interface for various misfolded proteins, promoting their aggregation. p300 enhances aggregation of TAU and of p53 and is a component of cellular aggregates in both tissue culture cells and in alpha-synuclein positive Lewy bodies of patients affected by Parkinson disease. Down-regulation of p300 impairs aggresome formation and enhances cytotoxicity induced by misfolded protein stress. These data unravel a novel activity of p300, offer new insights into the function of disordered domains and implicate p300 in pathological aggregation that occurs in neurodegeneration and cancer.

Topics: alpha-Synuclein; Alternative Splicing; Amino Acid Sequence; Animals; Autophagy; Chlorocebus aethiops; COS Cells; Down-Regulation; Humans; Lewy Bodies; Molecular Sequence Data; Neoplasms; Neurodegenerative Diseases; Oxidative Stress; p300-CBP Transcription Factors; Parkinson Disease; Prions; Protein Denaturation; Protein Folding; Protein Structure, Tertiary; Sequence Homology, Amino Acid

A growing body of evidence demonstrates an association between vascular risk factors and Alzheimer's disease. This study investigated the frequency and severity of atherosclerotic plaques in the circle of Willis in Alzheimer's disease and multiple other neurodegenerative diseases. Semi-quantitative data from gross and microscopic neuropathological examinations in 1000 cases were analysed, including 410 with a primary diagnosis of Alzheimer's disease, 230 with synucleinopathies, 157 with TDP-43 proteinopathies, 144 with tauopathies and 59 with normal ageing. More than 77% of subjects with Alzheimer's disease had grossly apparent circle of Willis atherosclerosis, a percentage that was significantly higher than normal (47%), or other neurodegenerative diseases (43-67%). Age- and sex-adjusted atherosclerosis ratings were highly correlated with neuritic plaque, paired helical filaments tau neurofibrillary tangle and cerebral amyloid angiopathy ratings in the whole sample and within individual groups. We found no associations between atherosclerosis ratings and α-synuclein or TDP-43 lesion ratings. The association between age-adjusted circle of Willis atherosclerosis and Alzheimer's disease-type pathology was more robust for female subjects than male subjects. These results provide further confirmation and specificity that vascular disease and Alzheimer's disease are interrelated and suggest that common aetiologic or reciprocally synergistic pathophysiological mechanisms promote both vascular pathology and plaque and tangle pathology.

Topics: Aged; Aged, 80 and over; Aging; alpha-Synuclein; Alzheimer Disease; Analysis of Variance; Cerebral Amyloid Angiopathy; Chi-Square Distribution; Circle of Willis; Dementia; DNA-Binding Proteins; Female; Humans; Intracranial Arteriosclerosis; Male; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; Retrospective Studies; Risk Factors

Atomic force microscopy (AFM) force spectroscopy is a technique with broad nanomedical applications, widely used for the characterization of molecular interactions on the nanoscale. Here we test this technique to evaluate compounds for influencing the protein aggregation process. The results demonstrate that Zn(2+) or Al(3+) cations bring about a dramatic increase of α-synuclein interactions in unfavorable conditions for α-synuclein misfolding (neutral pH). We did not observe the effect of dopamine at favorable conditions for α-synuclein misfolding (acidic pH). We also found that electrostatic interactions do not play a significant role at acidic pH. These findings are generally in line with previous studies by various techniques. The high sensitivity of AFM force spectroscopy as well as its ability to test compounds for the same experimental system makes AFM an efficient nanotool for rapid analysis of compounds inhibiting early protein aggregation studies and quantitative selection of potential therapeutics for neurodegenerative diseases.. Atomic force microscopy is used to interrogate the influence of cations and α-synuclein on the protein aggregation process. The report illustrates an application of AFM to unravel the potential of novel therapeutics on early protein aggregation intrinsic in neurodegenerative diseases.

Topics: alpha-Synuclein; Aluminum; Cations; Humans; Hydrogen-Ion Concentration; Microscopy, Atomic Force; Nanomedicine; Neurodegenerative Diseases; Protein Folding; Static Electricity; Zinc

The well-documented link between α-synuclein and the pathology of common human neurodegenerative diseases has increased attention to the synuclein protein family. The involvement of α-synuclein in lipid metabolism in both normal and diseased nervous system has been shown by many research groups. However, the possible involvement of γ-synuclein, a closely-related member of the synuclein family, in these processes has hardly been addressed. In this study, the effect of γ-synuclein deficiency on the lipid composition and fatty acid patterns of individual lipids from two brain regions has been studied using a mouse model. The level of phosphatidylserine (PtdSer) was increased in the midbrain whereas no changes in the relative proportions of membrane polar lipids were observed in the cortex of γ-synuclein-deficient compared to wild-type (WT) mice. In addition, higher levels of docosahexaenoic acid were found in PtdSer and phosphatidylethanolamine (PtdEtn) from the cerebral cortex of γ-synuclein null mutant mice. These findings show that γ-synuclein deficiency leads to alterations in the lipid profile in brain tissues and suggest that this protein, like α-synuclein, might affect neuronal function via modulation of lipid metabolism.

Topics: alpha-Synuclein; Animals; Cerebral Cortex; Disease Models, Animal; Fatty Acids; gamma-Synuclein; Male; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurodegenerative Diseases; Neurons

Parkinson's disease (PD) involves both motor and non-motor disturbances. Non-motor features include alterations in sensory olfactory function which may constitute a viable biomarker for the disorder. It is not clear what causes olfactory dysfunction but it appears to coincide with the development of synucleopathy within the olfactory bulb (OB). Elevation in alpha-synuclein (a-syn) is indeed a risk factor for development of the sporadic disorder. The multifactorial nature of the idiopathic disease combined with variability in its presentation suggests that it is likely to be influenced by several factors and that in vivo models that explore the synergistic effect of alpha-synuclein elevation with other potential contributing factors are likely to be of importance in understanding the disease etiology. Using a dual transgenic (DTg) mouse model of dopaminergic alpha-synuclein overexpression coupled with doxycycline (Dox)-inducible glutathione (GSH) depletion in these same cells, we demonstrate an age-related loss in behavioral olfactory function coupled with a significant neurodegeneration of glomerular dopaminergic neurons. This is accompanied by increase in alpha-synuclein levels in non-dopaminergic cells in the granule cell layer (GCL). In addition, isolated olfactory bulb synaptosomes from dual transgenic lines with Dox consistently showed a slight but significant reduction in maximum mitochondrial respiration compared to controls. These results suggest that in the presence of increased oxidative stress, increased alpha-synuclein expression within dopaminergic OB neurons results in neurodegeneration in the glomerular layer (GL) and increased alpha-synuclein levels in the granular cell layer which coincide with olfactory dysfunction.

Topics: Aging; alpha-Synuclein; Animals; Dopamine; Female; Glutathione; Male; Mice; Mice, Transgenic; Neurodegenerative Diseases; Olfaction Disorders; Olfactory Bulb; Oxidative Stress; Parkinson Disease; Up-Regulation

Despite their potential importance as therapeutic targets, the initial events in neurodegenerative diseases are poorly understood. Emerging evidence suggests that presynaptic dysfunction might be an early event in these pathologies, and three papers now link dysregulation of SNAREprotein levels and function caused by the absence of synuclein or cysteine string protein (CSP) to activity-dependent neurodegeneration.

Topics: alpha-Synuclein; Animals; Cells, Cultured; HSP40 Heat-Shock Proteins; Membrane Proteins; Mice; Mice, Knockout; Mice, Transgenic; Models, Neurological; Neurodegenerative Diseases; Neurons; Protein Binding; SNARE Proteins; Synaptic Transmission; Synaptic Vesicles; Synaptosomal-Associated Protein 25

Mechanisms whereby gene-environment interactions mediate chronic, progressive neurodegenerative processes in Parkinson's disease (PD)-the second most common neurodegenerative disease-remain elusive.. We created a two-hit [neuroinflammation and mutant α-synuclein (α-syn) overexpression] animal model to investigate mechanisms through which mutant α-syn and inflammation work in concert to mediate chronic PD neurodegeneration.. We used an intraperitoneal injection of the inflammogen lipopolysaccharide (LPS; 3 × 106 EU/kg) to initiate systemic and brain inflammation in wild-type (WT) mice and transgenic (Tg) mice overexpressing human A53T mutant α-syn. We then evaluated nigral dopaminergic neurodegeneration, α-syn pathology, and neuroinflammation.. After LPS injection, both WT and Tg mice initially displayed indistinguishable acute neuroinflammation; however, only Tg mice developed persistent neuroinflammation, chronic progressive degeneration of the nigrostriatal dopamine pathway, accumulation of aggregated, nitrated α-syn, and formation of Lewy body-like inclusions in nigral neurons. Further mechanistic studies indicated that 4-week infusion of two inhibitors of inducible nitric oxide synthase and NADPH oxidase, major free radical-generating enzymes in activated microglia, blocked nigral α-syn pathology and neurodegeneration in LPS-injected Tg mice.. Microglia-derived oxidative stress bridged neuroinflammation and α-syn pathogenic alteration in mediating chronic PD progression. Our two-hit animal model involving both a genetic lesion and an environmental trigger reproduced key features of PD and demonstrated synergistic effects of genetic predisposition and environmental exposures in the development of PD. The chronic progressive nature of dopaminergic neurodegeneration, which is absent in most existing PD models, makes this new model invaluable for the study of mechanisms of PD progression.

Topics: alpha-Synuclein; Amidines; Animals; Animals, Genetically Modified; Benzylamines; Disease Models, Animal; Injections, Intraperitoneal; Lewy Bodies; Lipopolysaccharides; Mice; NADPH Oxidases; Nerve Degeneration; Neurodegenerative Diseases; Nitric Oxide Synthase Type II; Onium Compounds; Oxidative Stress; Parkinson Disease; Substantia Nigra

A consensus about the functions of human wild-type or mutated α-synuclein (αSYN) is lacking. Both forms of αSYN are implicated in Parkinson's disease, whereas the wild-type form is implicated in substance abuse. Interactions with other cellular proteins and organelles may meditate its functions. We developed a series of congenic mouse lines containing various allele doses or combinations of the human wild-type αSYN (hwαSYN) or a doubly mutated (A30P*A53T) αSYN (hm(2) αSYN) in a C57Bl/6J line spontaneously deleted in mouse αSYN (C57BL/6JOla). Both transgenes had a functional role in the nigrostriatal system, demonstrated by significant elevations in striatal catecholamines, metabolites and the enzyme tyrosine hydroxylase compared with null-mice without a transgene. Consequences occurred when the transgenes were expressed at a fraction of the endogenous level. Hemizygous congenic mice did not exhibit any change in the number or size of dopaminergic neurons in the ventral midbrain at 9 months of age. Human αSYN was predominantly located in neuronal cell bodies, neurites, synapses, and in intraneuronal/intraneuritic aggregates. The hm(2) αSYN transgene resulted in more aggregates and dystrophic neurites than did the hw5 transgene. The hwαSYN transgene resulted in higher expression of two striatal proteins, synaptogamin 7 and UCHL1, compared with the levels of the hm(2) αSYN transgene. These observations suggest that mutations in αSYN may impair specific functional domains, leaving others intact. These lines may be useful for exploring interactions between hαSYN and environmental or genetic risk factors in dopamine-related disorders using a mouse model.

Topics: alpha-Synuclein; Animals; Catecholamines; Chromatography, High Pressure Liquid; Corpus Striatum; Hippocampus; Humans; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Neurodegenerative Diseases; Neurons; Substance-Related Disorders; Synapses; Transgenes

Aggregates of the protein α-synuclein are the main component of Lewy bodies, the hallmark of Parkinson's disease. α-Synuclein aggregates are also found in many human neurodegenerative diseases known as synucleinopathies. In vivo, α-synuclein associates with membranes and adopts α-helical conformations. The details of how α-synuclein converts from the functional native state to amyloid aggregates remain unknown. In this study, we use maltose-binding protein (MBP) as a carrier to crystallize segments of α-synuclein. From crystal structures of fusions between MBP and four segments of α-synuclein, we have been able to trace a virtual model of the first 72 residues of α-synuclein. Instead of a mostly α-helical conformation observed in the lipid environment, our crystal structures show α-helices only at residues 1-13 and 20-34. The remaining segments are extended loops or coils. All of the predicted fiber-forming segments based on the 3D profile method are in extended conformations. We further show that the MBP fusion proteins with fiber-forming segments from α-synuclein can also form fiber-like nano-crystals or amyloid-like fibrils. Our structures suggest intermediate states during amyloid formation of α-synuclein.

Topics: alpha-Synuclein; Amino Acid Sequence; Amyloid; Crystallography, X-Ray; Humans; Maltose-Binding Proteins; Models, Molecular; Molecular Sequence Data; Neurodegenerative Diseases; Protein Conformation; Protein Structure, Tertiary; Recombinant Fusion Proteins

Although alpha-synuclein is the main constituent of Lewy bodies, cerebrospinal fluid determination on its own does not seem fundamental for the diagnosis of synucleinopathies. We evaluated whether the combination of classical biomarkers, Aβ(1-42) , total tau, phosphorylated tau, and α-synuclein can improve discrimination of Parkinson's disease, dementia with Lewy bodies, Alzheimer's disease, and frontotemporal dementia. Aβ(1-42) , total tau, phosphorylated tau, and α-synuclein were measured in a series of patients with Parkinson's disease (n = 38), dementia with Lewy bodies (n = 32), Alzheimer's disease (n = 48), frontotemporal dementia (n = 31), and age-matched control patients with other neurological diseases (n = 32). Mean α-synuclein levels in cerebrospinal fluid were significantly lower in the pathological groups than in cognitively healthy subjects. An inverse correlation of α-synuclein with total tau (r = -0.196, P < .01) was observed. In the group of patients with Parkinson's disease, Aβ(1-42) , total tau, and phosphorylated tau values were similar to controls, whereas total tau/α-synuclein and phosphorylated tau/α-synuclein ratios showed the lowest values. Cerebrospinal fluid α-synuclein alone did not provide relevant information for Parkinson's disease diagnosis, showing low specificity (area under the curve, 0.662; sensitivity, 94%; specificity, 25%). Instead, a better performance was obtained with the total tau/α-syn ratio (area under the curve, 0.765; sensitivity, 89%; specificity, 61%). Combined determination of α-synuclein and classical biomarkers in cerebrospinal fluid shows differential patterns in neurodegenerative disorders. In particular, total tau/α-synuclein and phosphorylated tau/α-synuclein ratios can contribute to the discrimination of Parkinson's disease. © 2011 Movement Disorder Society.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Analysis of Variance; Dementia; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Neurodegenerative Diseases; Parkinson Disease; Peptide Fragments; Phosphorylation; Prospective Studies; ROC Curve; tau Proteins

Biomarker development is important to the therapeutic imperative for neurodegenerative diseases, as biomarkers hold transformative promise for the design and conduct of clinical trials and, ultimately, for medical management of these diseases. Some of this promise is now being realized in Alzheimer disease, and progress in Parkinson disease is accelerating.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Biomarkers; Humans; Neurodegenerative Diseases; Parkinson Disease; tau Proteins

α-Synuclein (α-Syn) is a key protein that accumulates as hyperphosphorylated aggregates in pathologic hallmark features of Parkinson's disease (PD) and other neurodegenerative disorders. Phosphorylation of this protein at serine 129 is believed to promote its aggregation and neurotoxicity, suggesting that this post-translational modification could be a therapeutic target. Here, we demonstrate that phosphoprotein phosphatase 2A (PP2A) dephosphorylates α-Syn at serine 129 and that this activity is greatly enhanced by carboxyl methylation of the catalytic C subunit of PP2A. α-Syn-transgenic mice raised on a diet supplemented with eicosanoyl-5-hydroxytryptamide, an agent that enhances PP2A methylation, dramatically reduced both α-Syn phosphorylation at Serine 129 and α-Syn aggregation in the brain. These biochemical changes were associated with enhanced neuronal activity, increased dendritic arborizations, and reduced astroglial and microglial activation, as well as improved motor performance. These findings support the notion that serine 129 phosphorylation of α-Syn is of pathogenetic significance and that promoting PP2A activity is a viable disease-modifying therapeutic strategy for α-synucleinopathies such as PD.

Topics: alpha-Synuclein; Animals; Astrocytes; Blotting, Western; Brain; Cell Line; Cells, Cultured; Dendrites; Disease Models, Animal; Immunohistochemistry; Methylation; Mice; Mice, Transgenic; Microglia; Neurodegenerative Diseases; Neurons; Phosphoprotein Phosphatases; Phosphorylation; Serotonin

The prevalence of neurodegenerative disorders increases dramatically with advancing age. Although in recent decades the study of many neurodegenerative disorders has evolved greatly, the concept of neurodegeneration still remains elusive. Although neurodegenerative disorders are classified according to the major components of protein deposits, coexpression of several abnormal proteins in the brain tissue is more common than that was previously thought. The aim of this report is to describe the type of protein deposits found in brains with neuropathological diagnosis of neurodegenerative disease. The report shows the experience obtained in the Brain Bank of Navarra (Spain). The target population for this retrospective descriptive study comprised 178 brains autopsied in the "Hospital of Navarra" in Pamplona between 1994 and 2004 and 201 brains donated to the Brain Bank of Pamplona between 2004 and 2009. The diagnosis of the 201 brains from the Brain Bank was 62 (30.8%) Alzheimer's disease (AD), 43 (21.3%) multiprotein deposit, 31 (15.4%) α-synucleinopathies, 31 (15.4%) frontotemporal lobar degeneration (FTLD), 17 (8.4%) tauopathies, 9 (4.4%) prion disease, 6 (2.9%) vascular dementia (VD), and 2 (0.9%) Huntington's disease. Among the 43 cases with multiprotein deposits, we found 35 brains with deposits of 3 proteins (tau, β-amyloid, and α-synuclein). In these two series of brains, the high incidence of deposition of multiple proteins in neurodegenerative disorders is shown. Our results are in agreement with previous findings showing that tau, β-amyloid, and α-synuclein are the proteins most frequently deposited together.

Topics: Aged, 80 and over; alpha-Synuclein; Amyloid beta-Protein Precursor; Autopsy; Brain; Humans; Immunoenzyme Techniques; Neurodegenerative Diseases; Retrospective Studies; Spain; tau Proteins; Tissue Banks

Toll-like receptors (TLRs) mediate innate immunity, and their dysregulation may play a role in α-synucleinopathies, such as Parkinson's disease or multiple system atrophy (MSA). The aim of this study was to define the role of TLR4 in α-synuclein-linked neurodegeneration. Ablation of TLR4 in a transgenic mouse model of MSA with oligodendroglial α-synuclein overexpression augmented motor disability and enhanced loss of nigrostriatal dopaminergic neurons. These changes were associated with increased brain levels of α-synuclein linked to disturbed TLR4-mediated microglial phagocytosis of α-synuclein. Furthermore, tumor necrosis factor-α levels were increased in the midbrain and associated with a proinflammatory astroglial response. Our data suggest that TLR4 ablation impairs the phagocytic response of microglia to α-synuclein and enhances neurodegeneration in a transgenic MSA mouse model. The study supports TLR4 signaling as innate neuroprotective mechanism acting through clearance of α-synuclein.

Topics: alpha-Synuclein; Animals; Behavior, Animal; Cell Line, Tumor; DNA Primers; Dopaminergic Neurons; Enzyme-Linked Immunosorbent Assay; Inflammation; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Confocal; Models, Biological; Neurodegenerative Diseases; Phenotype; Substantia Nigra; Toll-Like Receptor 4

Synucleinopathies are a group of neurodegenerative disorders associated with the formation of aberrant amyloid inclusions composed of the normally soluble presynaptic protein α-synuclein (α-syn). Parkinson disease is the most well known of these disorders because it bears α-syn pathological inclusions known as Lewy bodies (LBs). Mutations in the gene for α-syn, including the E46K missense mutation, are sufficient to cause Parkinson disease as well as other synucleinopathies like dementia with LBs. Herein, we describe transgenic mice expressing E46K human α-syn in CNS neurons that develop detrimental age-dependent motor impairments. These animals accumulate age-dependent intracytoplasmic neuronal α-syn inclusions that parallel disease and recapitulate the biochemical, histological, and morphological properties of LBs. Surprisingly, the morphology of α-syn inclusions in E46K human α-syn transgenic mice more closely resemble LBs than the previously described transgenic mice (line M83) that express neuronal A53T human α-syn. E46K human α-syn mice also develop abundant neuronal tau inclusions that resemble neurofibrillary tangles. Subsequent studies on the ability of E46K α-syn to induce tau inclusions in cellular models suggest that both direct and indirect mechanisms of protein aggregation are probably involved in the formation of the tau inclusions observed here in vivo. Re-evaluation of presymptomatic transgenic mice expressing A53T human α-syn reveals that the formation of α-syn inclusions in mice must be synchronized; however, inclusion formation is diffuse within affected areas of the neuroaxis such that there was no clustering of inclusions. Collectively, these findings provide insights in the mechanisms of formation of these aberrant proteinaceous inclusions and support the notion that α-syn aggregates are involved in the pathogenesis of human diseases.

Topics: Age Factors; alpha-Synuclein; Animals; Brain; Cytoplasm; Humans; Immunohistochemistry; Mice; Mice, Transgenic; Models, Biological; Neurodegenerative Diseases; Phenotype; Protein Folding; Spinal Cord; tau Proteins; Time Factors; Transgenes

Increasing evidence links diverse forms of air pollution to neuroinflammation and neuropathology in both human and animal models, but the effects of long-term exposures are poorly understood.. We explored the central nervous system consequences of subchronic exposure to diesel exhaust (DE) and addressed the minimum levels necessary to elicit neuroinflammation and markers of early neuropathology.. Male Fischer 344 rats were exposed to DE (992, 311, 100, 35 and 0 μg PM/m³) by inhalation over 6 months.. DE exposure resulted in elevated levels of TNFα at high concentrations in all regions tested, with the exception of the cerebellum. The midbrain region was the most sensitive, where exposures as low as 100 μg PM/m³ significantly increased brain TNFα levels. However, this sensitivity to DE was not conferred to all markers of neuroinflammation, as the midbrain showed no increase in IL-6 expression at any concentration tested, an increase in IL-1β at only high concentrations, and a decrease in MIP-1α expression, supporting that compensatory mechanisms may occur with subchronic exposure. Aβ42 levels were the highest in the frontal lobe of mice exposed to 992 μg PM/m³ and tau [pS199] levels were elevated at the higher DE concentrations (992 and 311 μg PM/m³) in both the temporal lobe and frontal lobe, indicating that proteins linked to preclinical Alzheimer's disease were affected. α Synuclein levels were elevated in the midbrain in response to the 992 μg PM/m³ exposure, supporting that air pollution may be associated with early Parkinson's disease-like pathology.. Together, the data support that the midbrain may be more sensitive to the neuroinflammatory effects of subchronic air pollution exposure. However, the DE-induced elevation of proteins associated with neurodegenerative diseases was limited to only the higher exposures, suggesting that air pollution-induced neuroinflammation may precede preclinical markers of neurodegenerative disease in the midbrain.

Topics: Air Pollutants; Air Pollution; alpha-Synuclein; Animals; Biomarkers; Brain; Chemokines; Cytokines; Encephalitis; Humans; Inhalation Exposure; Male; Neurodegenerative Diseases; Rats; Rats, Inbred F344; tau Proteins; Vehicle Emissions

Dysregulation of dopamine (DA) homeostasis is implicated in neurodegenerative diseases, drug addiction, and neuropsychiatric disorders. The neuronal plasma membrane dopamine transporter (DAT) is essential for the maintenance of DA homeostasis in the brain. α-Synuclein is a 140-amino acid protein that forms a stable complex with DAT and is linked to the pathogenesis of neurodegenerative disease. To elucidate the potential functional consequences of DAT/α-synuclein interaction, we explored α-synuclein modulation of DAT activity in midbrain dopaminergic neurons obtained from TH::RFP mice, immortalized DA neurons, and a heterologous system expressing DAT. We used dual pipette whole cell patch clamp recording to measure the DAT-mediated current before and after dialysis of recombinant α-synuclein into immortalized DA neurons. Our data suggest that intracellular α-synuclein induces a Na+ independent but Cl--sensitive inward current in DAT-expressing cells. This current is blocked by DAT blocker GBR12935 and is absent when heat-inactivated α-synuclein is dialyzed into these cells. The functional consequence of this interaction on DAT activity was further examined with real-time monitoring of transport function using a fluorescent substrate of DAT, 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP+). Overexpression of α-synuclein in DAT-positive immortalized DA neurons and CHO cells expressing DAT decreased the magnitude and rate of DAT-mediated substrate uptake without a decrease in the initial binding of the substrate at the plasma membrane. Taken together our findings are consistent with the interpretation that DAT/α-synuclein interaction at the cell surface results in a DAT-dependent, Na+-insensitive, Cl-sensitive inward current with a decrease in substrate uptake, suggesting that DAT/α-synuclein interaction can modulate dopamine transmission and thus neuronal function.

Topics: alpha-Synuclein; Animals; Brain; Chlorides; CHO Cells; Cricetinae; Cricetulus; Dopamine; Dopamine Plasma Membrane Transport Proteins; Fluorescent Dyes; Humans; Mice; Neurodegenerative Diseases; Neurons; Patch-Clamp Techniques

Protein misfolding and aggregation is a critically important feature in many devastating neurodegenerative diseases, therefore characterization of the CSF concentration profiles of selected key forms and morphologies of proteins involved in these diseases, including β-amyloid (Aβ) and α-synuclein (a-syn), can be an effective diagnostic assay for these diseases. CSF levels of tau and Aβ have been shown to have great promise as biomarkers for Alzheimer's disease. However since the onset and progression of many neurodegenerative diseases have been strongly correlated with the presence of soluble oligomeric aggregates of proteins including various Aβ and a-syn aggregate species, specific detection and quantification of levels of each of these different toxic protein species in CSF may provide a simple and accurate means to presymptomatically diagnose and distinguish between these diseases. Here we show that the presence of different protein morphologies in human CSF samples can be readily detected using highly selective morphology specific reagents in conjunction with a sensitive electronic biosensor. We further show that these morphology specific reagents can readily distinguish between post-mortem CSF samples from AD, PD and cognitively normal sources. These studies suggest that detection of specific oligomeric aggregate species holds great promise as sensitive biomarkers for neurodegenerative disease.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Biosensing Techniques; Female; Humans; Male; Middle Aged; Neurodegenerative Diseases; Reproducibility of Results; Sensitivity and Specificity

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra (SN) and the appearance of fibrillar aggregates of insoluble α-synuclein (α-syn) called Lewy bodies (LBs). Approximately 90% of α-syn deposited in LBs is phosphorylated at serine 129 (Ser129). In contrast, only 4% of total α-syn is phosphorylated in normal brain, suggesting that accumulation of Ser129-phosphorylated α-syn is involved in the pathogenesis of PD. However, the role of Ser129 phosphorylation in α-syn neurotoxicity remains unclear. In this study, we coexpressed familial PD-linked A53T α-syn and G-protein-coupled receptor kinase 6 (GRK6) in the rat SN pars compacta using recombinant adeno-associated virus 2. Coexpression of these proteins yielded abundant Ser129-phosphorylated α-syn and significantly exacerbated degeneration of dopaminergic neurons when compared with coexpression of A53T α-syn and GFP. Immunohistochemical analysis revealed that Ser129-phosphorylated α-syn was preferentially distributed to swollen neurites. However, biochemical analysis showed that the increased expression of Ser129-phosphorylated α-syn did not promote accumulation of detergent-insoluble α-syn. Coexpression of catalytically inactive K215R mutant GRK6 failed to accelerate A53T α-syn-induced degeneration. Furthermore, introducing a phosphorylation-incompetent mutation, S129A, into A53T α-syn did not alter the pace of degeneration, even when GRK6 was coexpressed. Our study demonstrates that authentically Ser129-phosphorylated α-syn accelerates A53T α-syn neurotoxicity without the formation of detergent-insoluble α-syn, and suggests that the degenerative process could be constrained by inhibiting the kinase that phosphorylates α-syn at Ser129.

Topics: alpha-Synuclein; Animals; Cell Count; Cell Line, Transformed; Disease Models, Animal; Dopamine Plasma Membrane Transport Proteins; ELAV Proteins; G-Protein-Coupled Receptor Kinases; Gene Expression Regulation; Genetic Vectors; Green Fluorescent Proteins; Humans; Mutation; Neurodegenerative Diseases; Neurons; Parkinson Disease; Phosphorylation; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Serine; Substantia Nigra; Transduction, Genetic; Transfection; Tyrosine 3-Monooxygenase

Topics: Aged; alpha-Synuclein; Humans; Lewy Body Disease; Neurodegenerative Diseases; Parkinson Disease

Alpha synuclein (SNCA) has been linked to neurodegenerative diseases (synucleinopathies) that include Parkinson's disease (PD). Although the primary neurodegeneration in PD involves nigrostriatal dopaminergic neurons, more extensive yet regionally selective neurodegeneration is observed in other synucleinopathies. Furthermore, SNCA is ubiquitously expressed in neurons and numerous neuronal systems are dysfunctional in PD. Therefore it is of interest to understand how overexpression of SNCA affects neuronal function in regions not directly targeted for neurodegeneration in PD.. The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis.. The results support a key role for SNCA in synaptic function and revealed an apoptotic signature in Thy1-aSyn mice, which together with specific alterations of neuroprotective genes suggest the activation of adaptive compensatory mechanisms that may protect striatal neurons in conditions of neuronal overexpression of SNCA.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Female; Gene Expression Profiling; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Microarray Analysis; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Signal Transduction; Synapses

Braak proposed propagation staging paradigm of Lewy- related alpha-synucleinopathy, which starts from medulla oblongata and extends rostrally to neocortex. Since this propagation shares that of bovine spongiformic encephalopathy, alpha- synuclein- prionopathy hypothesis was presented and augumented by pathological reports of Lewy body pathology in fetal tansplants of midbrain to patients with Parkinson disease (PD). The prionopathy hypothesis expanded to include tau and TDP- 43, is now receiving considerable attention world wide. Laterality of clinical symptoms can be explained with this hypothesis in PD, amyotrophic lateral sclerosis- TDP43, frontotemoral lobar degeneration- semantic dementia- TDP43 and tauopathy including corticobasal degeneration and argyrophilic grain dementia. Major cons of prionopathy hypothesis is how to explain cell to cell transmission of intracellular amyloid- like proteins. Several clinical and experimental data are now accumulated to answer this question. The difference in speed of spread between prion disease and neurodegenerative disease could be explained by aggregation size of abnormal proteins. The hypothesis could also explain glinoneuronal interaction, which is receiving another hot topic of neurodeneration. We propose that seed, aggregation propagation of abnormal protein should form one factor of clinical progression of neurodegenerative diseases and can be a therapeutic targets in future research.

Topics: alpha-Synuclein; Amyloid beta-Peptides; DNA-Binding Proteins; Humans; Neurodegenerative Diseases; Prions; Proteins; tau Proteins

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

Neurological symptoms of patients suffering from neurodegenerative diseases such as Alzheimer's dementia (AD), Parkinson's disease (PD), or amyotrophic lateral sclerosis (ALS) often worsen during infections. We assessed the disease-modulating effects of recurrent systemic infections with the most frequent respiratory pathogen, Streptococcus pneumoniae, on the course of AD, PD, and ALS in mouse models of these neurodegenerative diseases [transgenic Tg2576 mice, (Thy1)-[A30P]alpha SYN mice, and Tg(SOD1-G93A) mice]. Mice were repeatedly challenged intraperitoneally with live S. pneumoniae type 3 and treated with ceftriaxone for 3 days. Infection caused an increase of interleukin-6 concentrations in brain homogenates. The clinical status of (Thy1)-[A30P]alpha SYN mice and Tg(SOD1-G93A) mice was monitored by repeated assessment with a clinical score. Motor performance was controlled by the tightrope test and the rotarod test. In Tg2576 mice, spatial memory and learning deficits were assessed in the Morris water maze. In none of the three mouse models onset or course of the disease as evaluated by the clinical tests was affected by the recurrent systemic infections performed. Levels of alpha-synuclein in brains of (Thy1)-[A30P]alpha SYN mice did not differ between infected animals and control animals. Plaque sizes and concentrations of A beta 1-40 and A beta 1-42 were not significantly different in brains of infected and uninfected Tg2576 mice. In conclusion, onset and course of disease in mouse models of three common neurodegenerative disorders were not influenced by repeated systemic infections with S. pneumoniae, indicating that the effect of moderately severe acute infections on the course of neurodegenerative diseases may be less pronounced than suspected.

Topics: Acute Disease; alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Amyotrophic Lateral Sclerosis; Animals; Anti-Bacterial Agents; Ceftriaxone; Disease Models, Animal; Disease Progression; Interleukin-6; Maze Learning; Memory Disorders; Mice; Mice, Transgenic; Neurodegenerative Diseases; Neuropsychological Tests; Parkinson Disease; Plaque, Amyloid; Pneumonia, Bacterial; Recurrence; Streptococcal Infections; Streptococcus pneumoniae; Up-Regulation

Intracellular alpha-synuclein (alpha-syn) aggregates are the pathological hallmark in several neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Recent evidence suggests that small oligomeric aggregates rather than large amyloid fibrils represent the main toxic particle species in these diseases. We recently characterized iron-dependent toxic alpha-syn oligomer species by confocal single molecule fluorescence techniques and used this aggregation model to identify several N'-benzylidene-benzohydrazide (NBB) derivatives inhibiting oligomer formation in vitro. In our current work, we used the bioluminescent protein-fragment complementation assay (BPCA) to directly analyze the formation of toxic alpha-syn oligomers in cell culture and to investigate the effect of iron and potential drug-like compounds in living cells. Similar to our previous findings in vitro, we found a converse modulation of toxic alpha-syn oligomers by NBB derivates and ferric iron, which was characterized by an increase in aggregate formation by iron and an inhibitory effect of certain NBB compounds. Inhibition of alpha-syn oligomer formation by the NBB compound 293G02 was paralleled by a reduction in cytotoxicity indicating that toxic alpha-syn oligomers are present in the BPCA cell culture model and that pharmacological inhibition of oligomer formation can reduce toxicity. Thus, this approach provides a suitable model system for the development of new disease-modifying drugs targeting toxic oligomer species. Moreover, NBB compounds such as 293G02 may provide useful tool compounds to dissect the functional role of toxic oligomer species in cell culture models and in vivo.

Topics: alpha-Synuclein; Cell Line, Tumor; Cells, Cultured; Humans; Hydrazines; Iron; Luciferases; Neurodegenerative Diseases

Trichloroethylene, a chlorinated solvent widely used as a degreasing agent, is a common environmental contaminant. Emerging evidence suggests that chronic exposure to trichloroethylene may contribute to the development of Parkinson's disease. The purpose of this study was to determine if selective loss of nigrostriatal dopaminergic neurons could be reproduced by systemic exposure of adult Fisher 344 rats to trichloroethylene. In our experiments, oral administration of trichloroethylene induced a significant loss of dopaminergic neurons in the substantia nigra pars compacta in a dose-dependent manner, whereas the number of both cholinergic and GABAergic neurons were not decreased in the striatum. There was a robust decline in striatal levels of 3, 4-dihydroxyphenylacetic acid without a significant depletion of striatal dopamine. Rats treated with trichloroethylene showed defects in rotarod behavior test. We also found a significantly reduced mitochondrial complex I activity with elevated oxidative stress markers and activated microglia in the nigral area. In addition, we observed intracellular alpha-synuclein accumulation in the dorsal motor nucleus of the vagus nerve, with some in nigral neurons, but little in neurons of cerebral cortex. Overall, our animal model exhibits some important features of Parkinsonism, and further supports that trichloroethylene may be an environmental risk factors for Parkinson's disease.

Topics: alpha-Synuclein; Animals; Caspase 3; CD11b Antigen; Choline O-Acetyltransferase; Chromatography, High Pressure Liquid; Disease Models, Animal; Dopamine; Dopamine and cAMP-Regulated Phosphoprotein 32; Dose-Response Relationship, Drug; Electrochemistry; Encephalitis; Gene Expression Regulation; Male; Mitochondria; Neurodegenerative Diseases; Oxidative Stress; Rats; Rats, Inbred F344; Rotarod Performance Test; Solvents; Substantia Nigra; Trichloroethylene; Tyrosine; Tyrosine 3-Monooxygenase

The goals of this study were to determine the effects of prolonged fixation time and to optimize antigen retrieval (AR) methods on immunohistochemical (IHC) staining of common neurodegenerative disease markers. A panel of commercial antibodies (Abs) to amyloid-beta, ubiquitin, p62/sequestosome, tau, and alpha-synuclein was applied to a 2-mm tissue microarray using several AR methods. The IHC outcomes were assessed in sections that included 2 types of specimens taken from 20 postmortem brains: short-term fixation of up to 70 days before paraffin embedment and long-term fixation of up to 14 years in formalin. Good amyloid-beta IHC staining was obtained with all amyloid-beta Abs applied when a formic acid AR method was used, even after 14 years of fixation. Ubiquitin immunoreactivity was also optimally labeled with this method. The p62/sequestosome IHC outcome was optimal for tissue fixed up to 10 years, but only when the p62-lck-ligand-Ab with heat AR method was used. All hyperphosphorylated tau Abs tested worked with fixation up to 10 years, in particular with the heat AR method, whereas Abs against tau isoforms RD3 and RD4 were applicable only when the fixation time was 6 months or shorter. alpha-Synuclein-immunoreactive structures were visualized up to 14 years but only by the use of Syn42-Ab after formic acid AR or after a combination of heat and formic acid methods.

Topics: Adaptor Proteins, Signal Transducing; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Brain; Humans; Immunohistochemistry; Neurodegenerative Diseases; Protein Array Analysis; Protein Isoforms; Sequestosome-1 Protein; Statistics, Nonparametric; tau Proteins; Time Factors; Tissue Fixation; Ubiquitin

Alpha-synuclein (alpha-syn) amyloid filaments are the major ultrastructural component of pathological inclusions that define several neurodegenerative disorders, including Parkinson disease and other disorders that are collectively termed synucleinopathies. Since the aggregation of alpha-syn is associated with the etiology of these diseases, defining the molecular elements that influence this process may have important therapeutics implication. The deletions of major portions of the hydrophobic region of alpha-syn (Delta74-79 and Delta71-82) impair the ability to form amyloid. However, mutating residue E83 to an A restored the ability of these proteins to form amyloid. Additionally supporting an inhibitory role of residue E83 on amyloid formation, mutating this residue to an A enhanced amyloid formation in the presence of small molecule inhibitors, such as dopamine and EGCG. Our data, therefore, suggest that the presence and placement of the highly charged E83 residue plays a significant inhibitory role in alpha-syn amyloid formation and these findings provide important insights in the planning of therapeutic agents that may be capable of preventing alpha-syn amyloid formation.

Topics: alpha-Synuclein; Amyloid; Catechin; Dopamine; Flavanones; Glutamic Acid; Humans; Mutation; Neurodegenerative Diseases; Neuroprotective Agents

Abnormal neuronal aggregation of alpha-synuclein is implicated in the development of many neurological disorders, including Parkinson disease and dementia with Lewy bodies. Glial cells also show extensive alpha-synuclein pathology and may contribute to disease progression. However, the mechanism that produces the glial alpha-synuclein pathology and the interaction between neurons and glia in the disease-inflicted microenvironment remain unknown. Here, we show that alpha-synuclein proteins released from neuronal cells are taken up by astrocytes through endocytosis and form inclusion bodies. The glial accumulation of alpha-synuclein through the transmission of the neuronal protein was also demonstrated in a transgenic mouse model expressing human alpha-synuclein. Furthermore, astrocytes that were exposed to neuronal alpha-synuclein underwent changes in the gene expression profile reflecting an inflammatory response. Induction of pro-inflammatory cytokines and chemokines correlated with the extent of glial accumulation of alpha-synuclein. Together, these results suggest that astroglial alpha-synuclein pathology is produced by direct transmission of neuronal alpha-synuclein aggregates, causing inflammatory responses. This transmission step is thus an important mediator of pathogenic glial responses and could qualify as a new therapeutic target.

Topics: alpha-Synuclein; Animals; Astrocytes; Cell Differentiation; Cell Line, Tumor; Culture Media, Conditioned; Humans; Inflammation; Male; Mice; Mice, Transgenic; Models, Biological; Neurodegenerative Diseases; Neurons; Rats; Rats, Sprague-Dawley

Increasing evidence suggests that phosphorylation may play an important role in the oligomerization, fibrillogenesis, Lewy body (LB) formation, and neurotoxicity of alpha-synuclein (alpha-syn) in Parkinson disease. Herein we demonstrate that alpha-syn is phosphorylated at S87 in vivo and within LBs. The levels of S87-P are increased in brains of transgenic (TG) models of synucleinopathies and human brains from Alzheimer disease (AD), LB disease (LBD), and multiple system atrophy (MSA) patients. Using antibodies against phosphorylated alpha-syn (S129-P and S87-P), a significant amount of immunoreactivity was detected in the membrane in the LBD, MSA, and AD cases but not in normal controls. In brain homogenates from diseased human brains and TG animals, the majority of S87-P alpha-syn was detected in the membrane fractions. A battery of biophysical methods were used to dissect the effect of S87 phosphorylation on the structure, aggregation, and membrane-binding properties of monomeric alpha-syn. These studies demonstrated that phosphorylation at S87 expands the structure of alpha-syn, increases its conformational flexibility, and blocks its fibrillization in vitro. Furthermore, phosphorylation at S87, but not S129, results in significant reduction of alpha-syn binding to membranes. Together, our findings provide novel mechanistic insight into the role of phosphorylation at S87 and S129 in the pathogenesis of synucleinopathies and potential roles of phosphorylation in alpha-syn normal biology.

Topics: alpha-Synuclein; Alzheimer Disease; Amino Acid Sequence; Animals; Brain; Cell Membrane; Creatine Kinase; Disease Models, Animal; Humans; Lewy Bodies; Lewy Body Disease; Male; Mice; Mice, Transgenic; Multiple System Atrophy; Neurodegenerative Diseases; Neurons; Parkinson Disease; Phosphorylation; Polymers; Protein Isoforms; Rats; Rats, Wistar; Serine

Aggregation of alpha-synuclein (alpha-syn), a process that generates oligomeric intermediates, is a common pathological feature of several neurodegenerative disorders. Despite the potential importance of the oligomeric alpha-syn intermediates in neuron function, their biochemical properties and pathobiological functions in vivo remain vastly unknown. Here we used two-dimensional analytical separation and an array of biochemical and cell-based assays to characterize alpha-syn oligomers that are present in the nervous system of A53T alpha-syn transgenic mice. The most prominent species identified were 53 A detergent-soluble oligomers, which preceded neurological symptom onset, and were found at equivalent amounts in regions containing alpha-syn inclusions as well as histologically unaffected regions. These oligomers were resistant to SDS, heat, and urea but were sensitive to proteinase-K digestion. Although the oligomers shared similar basic biochemical properties, those obtained from inclusion-bearing regions were prominently reactive to antibodies that recognize oxidized alpha-syn oligomers, significantly accelerated aggregation of alpha-syn in vitro, and caused primary cortical neuron degeneration. In contrast, oligomers obtained from non-inclusion-bearing regions were not toxic and delayed the in vitro formation of alpha-syn fibrils. These data indicate that specific conformations of alpha-syn oligomers are present in distinct brain regions of A53T alpha-syn transgenic mice. The contribution of these oligomers to the development of neuron dysfunction appears to be independent of their absolute quantities and basic biochemical properties but is dictated by the composition and conformation of the intermediates as well as unrecognized brain-region-specific intrinsic factors.

Topics: alpha-Synuclein; Amyloid; Animals; Antibodies; Antibody Specificity; Brain; Cells, Cultured; Female; Humans; Lewy Bodies; Lewy Body Disease; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molecular Weight; Neurodegenerative Diseases; Parkinson Disease; Peptide Fragments; Polymers; Promoter Regions, Genetic; Protein Conformation; PrPC Proteins; Solubility

The pathologies of major neurodegenerative diseases including Parkinson disease and Alzheimer disease have been well known for decades. More recently, advances in molecular genetics have suggested important mechanistic links between the pathology of these disorders and pathogenesis of neuronal dysfunction and death. Numerous animal models have been produced based on the new information emerging from human genetic studies. As a complement to traditional mouse models, a number of investigators have modeled neurodegenerative diseases in simple model organisms ranging from yeast to Drosophila. These simple genetic models often display remarkable pathological similarities to their cognate human disorders, and genetic and biochemical studies have yielded important insights into the pathogenesis of the human disorders. Use of these tractable simple models may become even more important as large amounts of genetic data emerge from genome-wide association studies in Alzheimer disease, Parkinson disease, and other neurodegenerative disorders.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Disease Models, Animal; Drosophila melanogaster; Genome-Wide Association Study; Humans; Huntington Disease; Models, Biological; Models, Genetic; Neurodegenerative Diseases; Neurons; Phosphorylation

The kinetics of aggregation of alpha-synuclein are usually studied by turbidity or Thio-T fluorescence. Here we follow the disappearance of monomers and the formation of early oligomers using fluorescence correlation spectroscopy. Alexa488-labeled A140C-synuclein was used as a fluorescent probe in trace amounts in the presence of excess unlabeled alpha-synuclein. Repeated short measurements produce a distribution of diffusion coefficients. Initially, a sharp peak is obtained corresponding to monomers, followed by a distinct transient population and the gradual formation of broader-sized distributions of higher oligomers. The kinetics of aggregation can be followed by the decreasing number of fast-diffusing species. Both the disappearance of fast-diffusing species and the appearance of turbidity can be fitted to the Finke-Watzky equation, but the apparent rate constants obtained are different. This reflects the fact that the disappearance of fast species occurs largely during the lag phase of turbidity development, due to the limited sensitivity of turbidity to the early aggregation process. The nucleation of the early oligomers is concentration-dependent and accompanied by a conformational change that precedes beta-structure formation, and can be visualized using fluorescence resonance energy transfer between the donor-labeled N-terminus and the acceptor-labeled cysteine in the mutant A140C.

Topics: alpha-Synuclein; Circular Dichroism; Dose-Response Relationship, Drug; Fluorescence Resonance Energy Transfer; Humans; Kinetics; Lasers; Microscopy, Confocal; Molecular Conformation; Neurodegenerative Diseases; Plasmids; Protein Conformation; Protein Structure, Secondary; Spectrometry, Fluorescence; Time Factors

Omi, also known as high temperature requirement factor A2 (HtrA2), is a serine protease that was originally identified as a proapoptotic protein. Like Smac/Diablo, it antagonizes inhibitor of apoptosis proteins when released into the cytosol on apoptotic stimulation. Loss of its protease activity in mnd2 (motor neuron degeneration 2) mice is associated with neurodegeneration. However, the detailed mechanisms by which Omi regulates the pathogenesis of neurodegenerative disease remain largely unknown. We report here that Omi participates in the pivotal cellular degradation process known as autophagy. It activates autophagy through digestion of Hax-1, a Bcl-2 family-related protein that represses autophagy in a Beclin-1 (mammalian homologue of yeast ATG6)-dependent pathway. Moreover, Omi-induced autophagy facilitates the degradation of neurodegenerative proteins such as pathogenic A53T α-synuclein and truncated polyglutamine-expanded huntingtin, as well as the endogenous autophagy substrate p62. Knockdown of Omi decreases the basal level of autophagy and increases the level of the above target proteins. Furthermore, S276C Omi, the protease-defective mutant found in mnd2 mice, fails to regulate autophagy. Increased autophagy substrates and the formation of aggregate structures are observed in the brains of mnd2 mice. These results identify Omi as a novel regulator of autophagy and suggest that Omi might be important in the cellular quality control of proteins involved in neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Blotting, Western; Fluorescent Antibody Technique; High-Temperature Requirement A Serine Peptidase 2; Huntingtin Protein; Intracellular Signaling Peptides and Proteins; Mice; Mitochondria; Mitochondrial Membranes; Mitochondrial Proteins; Mutant Proteins; Nerve Tissue Proteins; Neurodegenerative Diseases; Nuclear Proteins; Polymerase Chain Reaction; Proteins; Proto-Oncogene Proteins c-bcl-2; RNA, Small Interfering; Serine Endopeptidases; Signal Transduction; Stress, Physiological

Topics: alpha-Synuclein; Astrocytes; Caspase 3; Exocytosis; Humans; Lewy Bodies; Neurodegenerative Diseases

Fibrillar protein aggregates are the major pathological hallmark of several incurable, age-related, neurodegenerative disorders. These aggregates typically contain aggregation-prone pathogenic proteins, such as amyloid-beta in Alzheimer's disease and alpha-synuclein in Parkinson's disease. It is, however, poorly understood how these aggregates are formed during cellular aging. Here we identify an evolutionarily highly conserved modifier of aggregation, MOAG-4, as a positive regulator of aggregate formation in C. elegans models for polyglutamine diseases. Inactivation of MOAG-4 suppresses the formation of compact polyglutamine aggregation intermediates that are required for aggregate formation. The role of MOAG-4 in driving aggregation extends to amyloid-beta and alpha-synuclein and is evolutionarily conserved in its human orthologs SERF1A and SERF2. MOAG-4/SERF appears to act independently from HSF-1-induced molecular chaperones, proteasomal degradation, and autophagy. Our results suggest that MOAG-4/SERF regulates age-related proteotoxicity through a previously unexplored pathway, which will open up new avenues for research on age-related, neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Line; Cell Line, Tumor; Cellular Senescence; Humans; Intracellular Signaling Peptides and Proteins; Mice; Nerve Tissue Proteins; Neurodegenerative Diseases; Peptides; Proteins

The deposition of amyloid-like filaments in the brain is the central event in the pathogenesis of neurodegenerative diseases. Here we report cellular models of intracytoplasmic inclusions of α-synuclein, generated by introducing nucleation seeds into SH-SY5Y cells with a transfection reagent. Upon introduction of preformed seeds into cells overexpressing α-synuclein, abundant, highly filamentous α-synuclein-positive inclusions, which are extensively phosphorylated and ubiquitinated and partially thioflavin-positive, were formed within the cells. SH-SY5Y cells that formed such inclusions underwent cell death, which was blocked by small molecular compounds that inhibit β-sheet formation. Similar seed-dependent aggregation was observed in cells expressing four-repeat Tau by introducing four-repeat Tau fibrils but not three-repeat Tau fibrils or α-synuclein fibrils. No aggregate formation was observed in cells overexpressing three-repeat Tau upon treatment with four-repeat Tau fibrils. Our cellular models thus provide evidence of nucleation-dependent and protein-specific polymerization of intracellular amyloid-like proteins in cultured cells.

Topics: alpha-Synuclein; Cell Death; Cell Line, Tumor; Humans; Inclusion Bodies; Models, Biological; Neurodegenerative Diseases; Phosphorylation; Protein Structure, Secondary; tau Proteins

Tau aggregation is a pathological hallmark of Alzheimer's disease, Parkinson's disease, and many other neurodegenerative disorders known as tauopathies. Tau aggregates take on many forms, and their formation is a multistage process with intermediate stages. Recently, tau oligomers have emerged as the pathogenic species in tauopathies and a possible mediator of amyloid-β toxicity in Alzheimer's disease. Here, we use a novel, physiologically relevant method (oligomer cross-seeding) to prepare homogeneous populations of tau oligomers and characterize these oligomers in vitro. We show that both Aβ and α-synuclein oligomers induce tau aggregation and the formation of β-sheet-rich neurotoxic tau oligomers.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Cell Line, Tumor; Humans; Neurodegenerative Diseases; Protein Multimerization; Protein Structure, Secondary; tau Proteins

Advances in medical science have led to increased life expectancy and increased median age in the population. Because the symptoms of neurodegenerative diseases generally onset in mid- to late-life, a concomitant increase in the number of persons afflicted with these devastating diseases has occurred. Developing therapies for neurodegenerative diseases is of the highest priority due to the enormous cost of medical care required, as well as for the human suffering involved. Although caused by a variety of genetic and environmental insults, such diseases share commonalities. Many of these diseases are proteinopathies--diseases caused by misfolded, aggregating proteins. Antibodies that can recognize and remove misfolded proteins are ideally suited for proteinopathy therapeutics. The numerous intriguing advances in antibody-based therapies for neurodegenerative diseases are discussed in this review.

Topics: alpha-Synuclein; Amyloid beta-Protein Precursor; Animals; Disease Models, Animal; Humans; Huntingtin Protein; Immunoglobulins, Intravenous; Mice; Nerve Tissue Proteins; Neurodegenerative Diseases; Nuclear Proteins; Protein Conformation; tau Proteins

Dementia with Lewy bodies (DLB) and Parkinson's Disease (PD) are neurodegenerative disorders of the aging population characterized by the abnormal accumulation of alpha-synuclein (alpha-syn). Previous studies have suggested that excitotoxicity may contribute to neurodegeneration in these disorders, however the underlying mechanisms and their relationship to alpha-syn remain unclear. For this study we proposed that accumulation of alpha-syn might result in alterations in metabotropic glutamate receptors (mGluR), particularly mGluR5 which has been linked to deficits in murine models of PD. In this context, levels of mGluR5 were analyzed in the brains of PD and DLB human cases and alpha-syn transgenic (tg) mice and compared to age-matched, unimpaired controls, we report a 40% increase in the levels of mGluR5 and beta-arrestin immunoreactivity in the frontal cortex, hippocampus and putamen in DLB cases and in the putamen in PD cases. In the hippocampus, mGluR5 was more abundant in the CA3 region and co-localized with alpha-syn aggregates. Similarly, in the hippocampus and basal ganglia of alpha-syn tg mice, levels of mGluR5 were increased and mGluR5 and alpha-syn were co-localized and co-immunoprecipitated, suggesting that alpha-syn interferes with mGluR5 trafficking. The increased levels of mGluR5 were accompanied by a concomitant increase in the activation of downstream signaling components including ERK, Elk-1 and CREB. Consistent with the increased accumulation of alpha-syn and alterations in mGluR5 in cognitive- and motor-associated brain regions, these mice displayed impaired performance in the water maze and pole test, these behavioral alterations were reversed with the mGluR5 antagonist, MPEP. Taken together the results from study suggest that mGluR5 may directly interact with alpha-syn resulting in its over activation and that this over activation may contribute to excitotoxic cell death in select neuronal regions. These results highlight the therapeutic importance of mGluR5 antagonists in alpha-synucleinopathies.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Autopsy; Brain; Excitatory Amino Acid Antagonists; Female; Humans; Immunoblotting; Immunohistochemistry; Lewy Body Disease; Male; Memory Disorders; Mice; Mice, Transgenic; Motor Activity; Neurodegenerative Diseases; Parkinson Disease; Pyridines; Receptor, Metabotropic Glutamate 5; Receptors, Metabotropic Glutamate; Signal Transduction

In this paper a hypothesis that some special signals ("key-signals" excito-amino acids, beta-amyloid peptides and alpha-synuclein) are not only involved in information handling by the neuronal circuits, but also trigger out substantial structural and/or functional changes in the Central Nervous System (CNS) is introduced. This forces the neuronal circuits to move from one stable state towards a new state, but in doing so these signals became potentially dangerous. Several mechanisms are put in action to protect neurons and glial cells from these potentially harmful signals. However, in agreement with the Red Queen Theory of Ageing (Agnati et al. in Acta Physiol Scand 145:301-309, 1992), it is proposed that during ageing these neuroprotective processes become less effective while, in the meantime, a shortage of brain plasticity occurs together with an increased need of plasticity for repairing the wear and tear of the CNS. The paper presents findings supporting the concept that such key-signals in instances such as ageing may favour neurodegenerative processes in an attempt of maximizing neuronal plasticity.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Brain; Dopamine; Glutamic Acid; Homocysteine; Humans; Learning; Models, Neurological; Nerve Degeneration; Neurodegenerative Diseases; Neuronal Plasticity; Neurons; Protein Conformation; Protein Multimerization; Signal Transduction

The association of alpha-synuclein (alpha-syn) neuropathology with Parkinson's disease (PD) and several related disorders has led to an intense research effort to develop cerebrospinal fluid (CSF)- or blood-based alpha-syn biomarkers for these types of diseases. Recent studies show that alpha-syn is present in CSF and possible to measure using enzyme-linked immunosorbent assay (ELISA). Here, we describe a novel ELISA that allows for quantification of alpha-syn in CSF down to 50pg/mL. The diagnostic value of the test was assessed using CSF samples from 66 Alzheimer's disease (AD) patients, 15PD patients, 15 patients with dementia with Lewy bodies (DLB) and 55 cognitively normal controls. PD and DLB patients and controls displayed similar CSF alpha-syn levels. AD patients had significantly lower alpha-syn levels than controls (median [inter-quartile range] 296 [234-372] and 395 [298-452], respectively, p<0.001). Moreover, AD patients with mini-mental state examination (MMSE) scores below 20 had significantly lower alpha-syn than AD patients with MMSE scores of 20 or higher (p=0.02). There was also a tendency towards a negative correlation between alpha-syn levels and disease duration in the AD group (r=-0.247, p=0.06). Altogether, our results speak against CSF alpha-syn as a reliable biomarker for PD and DLB. The lower alpha-syn levels in AD, as well as the association of alpha-syn reduction with AD severity, approximated by MMSE, suggests that it may be a general marker of synapse loss, a hypothesis that warrants further investigation.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Biomarkers; Brain; Down-Regulation; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lewy Body Disease; Male; Middle Aged; Neurodegenerative Diseases; Neuropsychological Tests; Parkinson Disease; Predictive Value of Tests; Synapses

The frequency of neurodegenerative markers among long surviving human immunodeficiency virus (HIV)-infected individuals is unknown, therefore, the present study investigated the frequency of alpha-synuclein, beta-amyloid, and HIV-associated brain pathology in the brains of older HIV-infected individuals. We examined the substantia nigra of 73 clinically well-characterized HIV-infected individuals aged 50 to 76 years from the National NeuroAIDS Tissue Consortium. We also examined the frontal and temporal cortical regions of a subset of 36 individuals. Neuritic alpha-synuclein expression was found in 16% (12/73) of the substantia nigra of the HIV+cases and none of the older control cases (0/18). beta-Amyloid deposits were prevalent and found in nearly all of the HIV+cases (35/36). Despite these increases of degenerative pathology, HIV-associated brain pathology was present in only 10% of cases. Among older HIV+adults, HIV-associated brain pathology does not appear elevated; however, the frequency of both alpha-synuclein and beta-amyloid is higher than that found in older healthy persons. The increased prevalence of alpha-synuclein and beta-amyloid in the brains of older HIV-infected individuals may predict an increased risk of developing neurodegenerative disease.

Topics: Age Factors; Aged; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Female; HIV; HIV Infections; Humans; Immunohistochemistry; Male; Middle Aged; Neurodegenerative Diseases; Substantia Nigra; Up-Regulation

We were interested in studying nigral degeneration with inclusion body formation and behavioral changes in rats after proteasomal inhibition.. Observation of progressive behavioral and pathological changes in rats following a unilateral nigral injection of lactacystin, a selective proteasome inhibitor.. After administration at a concentration of 10 microg (2 microl) of lactacystin, when tyrosine hydroxylase (TH) immunostaining decreased gradually in the substantia nigra pars compacta (SNc) and corpus striatum, alpha-synuclein-immunopositive inclusion appeared extensively in the surviving neurons. We also observed the degeneration of diverse cellular organelles by transmission electron microscopy. The effect of cellular organelle degeneration on behavior, a clinical index, was striking and was statistically significant. Over the 3 weeks following the administration of lactacystin, a highly significant decrease in TH immunostaining was observed and alpha-synuclein-immunopositive inclusions gradually appeared. Interestingly, there was a strong correlation in behavioral changes and the increase in alpha-synuclein-immunopositive inclusions whereas the decrease in TH immunostaining did not seem to induce any behavioral changes.. Our results reveal that unilateral nigral proteasome inhibition induces degeneration in the SNc and corpus striatum as well as behavioral changes demonstrating strong time dependence. Behavioral changes were driven by the formation of alpha-synuclein inclusions, but not by decreased TH neurons.

Topics: Acetylcysteine; alpha-Synuclein; Animals; Behavior, Animal; Corpus Striatum; Cysteine Proteinase Inhibitors; Disease Models, Animal; Hypokinesia; Inclusion Bodies; Male; Microscopy, Electron, Transmission; Motor Activity; Neurodegenerative Diseases; Neurons; Proteasome Inhibitors; Rats; Rats, Sprague-Dawley; Substantia Nigra; Tyrosine 3-Monooxygenase

Gangliosides may be involved in the pathogenesis of Parkinson's disease and related disorders, although the precise mechanisms governing this involvement remain unknown. In this study, we determined whether changes in endogenous ganglioside levels affect lysosomal pathology in a cellular model of synucleinopathy. For this purpose, dementia with Lewy body-linked P123H beta-synuclein (beta-syn) neuroblastoma cells transfected with alpha-synuclein were used as a model system because these cells were characterized as having extensive formation of lysosomal inclusions bodies. Treatment of these cells with D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), an inhibitor of glycosyl ceramide synthase, resulted in various features of lysosomal pathology, including compromised lysosomal activity, enhanced lysosomal membrane permeabilization, and increased cytotoxicity. Consistent with these findings, expression levels of lysosomal membrane proteins, ATP13A2 and LAMP-2, were significantly decreased, and electron microscopy demonstrated alterations in the lysosomal membrane structures. Furthermore, the accumulation of both P123H beta-syn and alpha-synuclein proteins was significant in PDMP-treated cells because of the suppressive effect of PDMP on the autophagy pathway. Finally, the detrimental effects of PDMP on lysosomal pathology were significantly ameliorated by the addition of gangliosides to the cultured cells. These data suggest that endogenous gangliosides may play protective roles against the lysosomal pathology of synucleinopathies.

Topics: alpha-Synuclein; Animals; Apoptosis; Autophagy; beta-Synuclein; Cell Membrane Permeability; Cells, Cultured; Enzyme Inhibitors; Fluorescent Antibody Technique; Gangliosides; Glucosyltransferases; Immunoblotting; Inclusion Bodies; Lysosomal-Associated Membrane Protein 2; Lysosomes; Morpholines; Neuroblastoma; Neurodegenerative Diseases; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

We have shown in the parkinsonism-inducing neurotoxin MPP(+)/MPTP model that alpha-Synuclein (alpha-Syn), a presynaptic protein causal in Parkinson's disease (PD), contributes to hyperphosphorylation of Tau (p-Tau), a protein normally linked to tauopathies, such as Alzheimer's disease (AD). Here, we investigated the kinase involved and show that the Tau-specific kinase, glycogen synthase kinase 3beta (GSK-3beta), is robustly activated in various MPP(+)/MPTP models of Parkinsonism (SH-SY5Y cotransfected cells, mesencephalic neurons, transgenic mice overexpressing alpha-Syn, and postmortem striatum of PD patients). The activation of GSK-3beta was absolutely dependent on the presence of alpha-Syn, as indexed by the absence of p-GSK-3beta in cells lacking alpha-Syn and in alpha-Syn KO mice. MPP(+) treatment induced translocation and accumulation of p-GSK-3beta in nuclei of SH-SY5Y cells and mesencephalic neurons. Through coimmunoprecipitation (co-IP), we found that alpha-Syn, pSer396/404-Tau, and p-GSK-3beta exist as a heterotrimeric complex in SH-SY5Y cells. GSK-3beta inhibitors (lithium and TDZD-8) protected against MPP(+)-induced events in SH-SY5Y cells, preventing cell death and p-GSK-3beta formation, by reversing increases in alpha-Syn accumulation and p-Tau formation. These data unveil a previously unappreciated role of alpha-Syn in the induction of p-GSK-3beta, and demonstrate the importance of this kinase in the genesis and maintenance of neurodegenerative changes associated with PD.

Topics: alpha-Synuclein; Animals; Catalysis; Disease Models, Animal; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Mice; Mice, Transgenic; Neurodegenerative Diseases; Parkinson Disease; Phosphorylation; tau Proteins; Transcriptional Activation

The two current major staging systems in use for Lewy body disorders fail to classify up to 50% of subjects. Both systems do not allow for large numbers of subjects who have Lewy-type alpha-synucleinopathy (LTS) confined to the olfactory bulb or who pass through a limbic-predominant pathway that at least initially bypasses the brainstem. The results of the current study, based on examination of a standard set of ten brain regions from 417 subjects stained immunohistochemically for alpha-synuclein, suggest a new staging system that, in this study, allows for the classification of all subjects with Lewy body disorders. The autopsied subjects included elderly subjects with Parkinson's disease, dementia with Lewy bodies, incidental Lewy body disease and Alzheimer's disease with Lewy bodies, as well as comparison groups without Lewy bodies. All subjects were classifiable into one of the following stages: I. Olfactory Bulb Only; IIa Brainstem Predominant; IIb Limbic Predominant; III Brainstem and Limbic; IV Neocortical. Progression of subjects through these stages was accompanied by a generally stepwise worsening in terms of striatal tyrosine hydroxylase concentration, substantia nigra pigmented neuron loss score, Mini Mental State Examination score and score on the Unified Parkinson's Disease Rating Scale Part 3. Additionally, there were significant correlations between these measures and LTS density scores. It is suggested that the proposed staging system would improve on its predecessors by allowing classification of a much greater proportion of cases.

Topics: Aged; Aged, 80 and over; Aging; alpha-Synuclein; Alzheimer Disease; Apolipoproteins E; Brain; Cognition Disorders; Diagnosis, Differential; Female; Humans; Immunohistochemistry; Lewy Body Disease; Male; Movement Disorders; Nerve Degeneration; Neurodegenerative Diseases; Parkinson Disease; Severity of Illness Index

ALpha-synuclein (alpha-syn) has been known to be a key player of the pathogenesis of Parkinson's disease and has recently been detected in extracellular biological fluids and shown to be rapidly secreted from cells. The penetration of alpha-syn into cells has also been observed. In this study, we observed that dl-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol, a glucosyltransferase inhibitor, and proteinase K inhibited the internalization of extracellular monomeric alpha-syn into BV-2 cells, and the addition of monosialoganglioside GM1 ameliorated the inhibition of alpha-syn internalization in dl-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol-treated BV-2 cells. Furthermore, inhibition of clathrin-, caveolae-, and dynamin-dependent endocytosis did not prevent the internalization of alpha-syn, but disruption of lipid raft inhibited it. Inhibition of macropinocytosis and disruption of actin and microtubule structures also did not inhibit the internalization of alpha-syn. In addition, we further confirmed these observations by co-culture system of BV-2 cells and alpha-syn-over-expressing SH-SY5Y cells. These findings suggest that extracellular alpha-syn is internalized into microglia via GM1 as well as hitherto-unknown protein receptors in clathrin-, caveolae-, and dynamin-independent, but lipid raft-dependent manner. Elucidation of the mechanism involved in internalization of alpha-syn should be greatly helpful in the development of new treatments of alpha-syn-related neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Caveolins; Cell Line; Cell Line, Tumor; Clathrin; Coculture Techniques; Dynamins; Encephalitis; Endocytosis; Endopeptidase K; Enzyme Inhibitors; Extracellular Space; G(M1) Ganglioside; Glucosyltransferases; Humans; Membrane Microdomains; Mice; Microglia; Neurodegenerative Diseases; Parkinson Disease; Protein Transport

Parkinson's disease (PD) is an adult-onset movement disorder of largely unknown etiology. We have previously shown that loss-of-function mutations of the mitochondrial protein kinase PINK1 (PTEN induced putative kinase 1) cause the recessive PARK6 variant of PD.. Now we generated a PINK1 deficient mouse and observed several novel phenotypes: A progressive reduction of weight and of locomotor activity selectively for spontaneous movements occurred at old age. As in PD, abnormal dopamine levels in the aged nigrostriatal projection accompanied the reduced movements. Possibly in line with the PARK6 syndrome but in contrast to sporadic PD, a reduced lifespan, dysfunction of brainstem and sympathetic nerves, visible aggregates of alpha-synuclein within Lewy bodies or nigrostriatal neurodegeneration were not present in aged PINK1-deficient mice. However, we demonstrate PINK1 mutant mice to exhibit a progressive reduction in mitochondrial preprotein import correlating with defects of core mitochondrial functions like ATP-generation and respiration. In contrast to the strong effect of PINK1 on mitochondrial dynamics in Drosophila melanogaster and in spite of reduced expression of fission factor Mtp18, we show reduced fission and increased aggregation of mitochondria only under stress in PINK1-deficient mouse neurons.. Thus, aging Pink1(-/-) mice show increasing mitochondrial dysfunction resulting in impaired neural activity similar to PD, in absence of overt neuronal death.

Topics: Adenosine Triphosphate; alpha-Synuclein; Animals; Disease Models, Animal; Female; Gene Expression Regulation; Male; Mice; Mice, Transgenic; Mitochondria; Neurodegenerative Diseases; Neurons; Parkinson Disease; Phenotype; Protein Kinases

Mutations in leucine-rich repeat kinase-2 (LRRK2) are the most common known cause of Parkinson disease, but how this protein results in the pathobiology of Parkinson disease is unknown. Moreover, there is variability in pathology among cases, and alpha-synuclein (alpha-syn) neuronal inclusions are often present, but whether LRRK2 is present in these pathological inclusions is controversial. This study characterizes novel LRRK2 antibodies, some of which preferentially recognize an aggregated form of LRRK2, as observed in cell culture models. Large perinuclear aggregates containing LRRK2 were promoted by proteasome inhibition and prevented by microtubule polymerization inhibition. Furthermore, they were vimentin- and gamma-tubulin- but not lamp1-immunoreactive, suggesting that these structures fit the definition of aggresomes. Inhibition of heat shock protein 90 led to the degradation of only the soluble/cytosolic pool of LRRK2, suggesting that the aggresomes formed independent of the stability provided by the heat shock protein 90. Although these novel anti-LRRK2 antibodies identified aggregates in model cell systems, they did not immunostain pathological inclusions in human brains. Furthermore, coexpression of LRRK2 and alpha-syn did not recruit alpha-syn into aggresomes in cultured cells, even in the presence of proteasome inhibition. Thus, although LRRK2 is a model system for aggresome formation, LRRK2 is not present in alpha-syn pathological inclusions.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Antibodies; Brain; Cell Line; Chlorocebus aethiops; COS Cells; Female; HSP90 Heat-Shock Proteins; Humans; Inclusion Bodies; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; Lewy Body Disease; Male; Middle Aged; Multiple System Atrophy; Neurodegenerative Diseases; Parkinson Disease; Protein Serine-Threonine Kinases

Increasing evidence links the misfolding and aberrant self-assembly of proteins with the molecular events that underlie a range of neurodegenerative diseases, yet the mechanistical details of these processes are still poorly understood. The fact that many of these proteins are intrinsically unstructured makes it particularly challenging to develop strategies for discovering small molecule inhibitors of their aggregation. We present here a broad biophysical approach that enables us to characterize the mechanisms of interaction between alpha-synuclein, a protein whose aggregation is closely connected with Parkinson's disease, and two small molecules, Congo red and Lacmoid, which inhibit its fibrillization. Both compounds are found to interact with the N-terminal and central regions of the monomeric protein although with different binding mechanisms and affinities. The differences can be attributed to the chemical nature of the compounds as well as their abilities to self-associate. We further show that alpha-synuclein binding and aggregation inhibition are mediated by small oligomeric species of the compounds that interact with distinct regions of the monomeric protein. These findings provide potential explanations of the nonspecific antiamyloid effect observed for these compounds as well as important mechanistical information for future drug discovery efforts targeting the misfolding and aggregation of intrinsically unstructured proteins.

Topics: alpha-Synuclein; Congo Red; Humans; Microscopy, Atomic Force; Molecular Sequence Data; Molecular Structure; Neurodegenerative Diseases; Parkinson Disease; Protein Conformation; Protein Folding; Signal Transduction; Small Molecule Libraries; Spectrophotometry, Ultraviolet

One of the greatest influenza pandemic threats at this time is posed by the highly pathogenic H5N1 avian influenza viruses. To date, 61% of the 433 known human cases of H5N1 infection have proved fatal. Animals infected by H5N1 viruses have demonstrated acute neurological signs ranging from mild encephalitis to motor disturbances to coma. However, no studies have examined the longer-term neurologic consequences of H5N1 infection among surviving hosts. Using the C57BL/6J mouse, a mouse strain that can be infected by the A/Vietnam/1203/04 H5N1 virus without adaptation, we show that this virus travels from the peripheral nervous system into the CNS to higher levels of the neuroaxis. In regions infected by H5N1 virus, we observe activation of microglia and alpha-synuclein phosphorylation and aggregation that persists long after resolution of the infection. We also observe a significant loss of dopaminergic neurons in the substantia nigra pars compacta 60 days after infection. Our results suggest that a pandemic H5N1 pathogen, or other neurotropic influenza virus, could initiate CNS disorders of protein aggregation including Parkinson's and Alzheimer's diseases.

Topics: alpha-Synuclein; Animals; Central Nervous System; Ganglia, Spinal; Immunohistochemistry; Inflammation; Influenza A Virus, H5N1 Subtype; Mice; Mice, Inbred C57BL; Neurodegenerative Diseases; Neurons; Orthomyxoviridae Infections; Phenotype; Phosphorylation; Virus Diseases

Parkinson disease (PD) involves progressive neurodegeneration, including loss of dopamine (DA) neurons from the substantia nigra. Select genes associated with rare familial forms of PD function in cellular pathways, such as the ubiquitin-proteasome system (UPS), involved in protein degradation. The misfolding and accumulation of proteins, such as alpha-synuclein, into inclusions termed Lewy Bodies represents a clinical hallmark of PD. Given the predominance of sporadic PD among patient populations, environmental toxins may induce the disease, although their nature is largely unknown. Thus, an unmet challenge surrounds the discovery of causal or contributory neurotoxic factors that could account for the prevalence of sporadic PD. Bacteria within the order Actinomycetales are renowned for their robust production of secondary metabolites and might represent unidentified sources of environmental exposures. Among these, the aerobic genera, Streptomyces, produce natural proteasome inhibitors that block protein degradation and may potentially damage DA neurons. Here we demonstrate that a metabolite produced by a common soil bacterium, S. venezuelae, caused DA neurodegeneration in the nematode, Caenorhabditis elegans, which increased as animals aged. This metabolite, which disrupts UPS function, caused gradual degeneration of all neuronal classes examined, however DA neurons were particularly vulnerable to exposure. The presence of DA exacerbated toxicity because neurodegeneration was attenuated in mutant nematodes depleted for tyrosine hydroxylase (TH), the rate-limiting enzyme in DA production. Strikingly, this factor caused dose-dependent death of human SH-SY5Y neuroblastoma cells, a dopaminergic line. Efforts to purify the toxic activity revealed that it is a highly stable, lipophilic, and chemically unique small molecule. Evidence of a robust neurotoxic factor that selectively impacts neuronal survival in a progressive yet moderate manner is consistent with the etiology of age-associated neurodegenerative diseases. Collectively, these data suggest the potential for exposures to the metabolites of specific common soil bacteria to possibly represent a contributory environmental component to PD.

Topics: Actinomycetales; Aging; alpha-Synuclein; Animals; Caenorhabditis elegans; Cell Line, Tumor; Culture Media, Conditioned; Dopamine; Environment; Humans; Leupeptins; Neurodegenerative Diseases; Protease Inhibitors; Protein Denaturation; Soil Microbiology; Streptomyces; Substantia Nigra

Topics: alpha-Synuclein; Amyloid beta-Peptides; Animals; Humans; Huntingtin Protein; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Nuclear Proteins; Prion Diseases; Prions; Protein Conformation; Protein Folding; Proteins; tau Proteins

Parkinson's disease (PD) is the second most common neurodegenerative disorder with approximately 2% of people over age 65 suffering from this disease. Risk factors for PD involve interplay between still poorly defined genetic and non-genetic contributors, but appear to converge upon cellular pathways that mediate protein misfolding and oxidative stress that lead to dopaminergic neuron loss. The identification of either new or repurposed drugs that exhibit benefit in slowing the age-dependent neuronal damage that occurs in PD is a significant goal of much ongoing research. We have exploited the nematode Caenorhabditis elegans as a model system by which the neuroprotective capacity of acetaminophen could be rapidly evaluated for efficacy in attenuating dopamine (DA) neurodegeneration. Using three independent and established neurodegenerative models in C. elegans, we assayed for acetaminophen-dependent rescue in response to: (1) over-expression of the PD-associated protein, alpha-synuclein; (2) acute exposure to 6-hydroxydopamine (6-OHDA); (3) excess intracellular DA production due to over-expression of the DA biosynthetic enzyme, tyrosine hydroxylase (TH). These data suggest that acetaminophen significantly protected C. elegans DA neurons from stressors related to oxidative damage, but not protein misfolding. Taken together, these studies imply an activity for acetaminophen in the attenuation of DA neuron loss that, following essential corroborative analyses in mammalian systems, may represent a potential benefit for PD.

Topics: Acetaminophen; Adrenergic Agents; alpha-Synuclein; Analgesics, Non-Narcotic; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Cell Count; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Gene Expression Regulation; Green Fluorescent Proteins; Neurodegenerative Diseases; Neurons; Oxidopamine; Parkinson Disease; Tyrosine 3-Monooxygenase

Mutations or multiplications in alpha-synuclein gene cause familial forms of Parkinson disease or dementia with Lewy bodies (LB), and the deposition of wild-type alpha-synuclein as LB occurs as a hallmark lesion of these disorders, collectively referred to as synucleinopathies, implicating alpha-synuclein in the pathogenesis of synucleinopathy. To identify modifier genes of alpha-synuclein-induced neurotoxicity, we conducted an RNAi screen in transgenic C. elegans (Tg worms) that overexpress human alpha-synuclein in a pan-neuronal manner. To enhance the RNAi effect in neurons, we crossed alpha-synuclein Tg worms with an RNAi-enhanced mutant eri-1 strain. We tested RNAi of 1673 genes related to nervous system or synaptic functions, and identified 10 genes that, upon knockdown, caused severe growth/motor abnormalities selectively in alpha-synuclein Tg worms. Among these were four genes (i.e. apa-2, aps-2, eps-8 and rab-7) related to the endocytic pathway, including two subunits of AP-2 complex. Consistent with the results by RNAi, crossing alpha-synuclein Tg worms with an aps-2 mutant resulted in severe growth arrest and motor dysfunction. alpha-Synuclein Tg worms displayed a decreased touch sensitivity upon RNAi of genes involved in synaptic vesicle endocytosis, and they also showed impaired neuromuscular transmission, suggesting that overexpression of alpha-synuclein caused a failure in uptake or recycling of synaptic vesicles. Furthermore, knockdown of apa-2, an AP-2 subunit, caused an accumulation of phosphorylated alpha-synuclein in neuronal cell bodies, mimicking synucleinopathy. Collectively, these findings raise a novel pathogenic link between endocytic pathway and alpha-synuclein-induced neurotoxicity in synucleinopathy.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Endocytosis; Humans; Motor Activity; Neurodegenerative Diseases; Neurons; Neurotransmitter Agents; Phosphorylation; RNA Interference; Synaptic Vesicles

Topics: alpha-Synuclein; Animals; Brain; Humans; Models, Biological; Neurodegenerative Diseases; Peptides; tau Proteins

alpha-Synuclein (SYN) is the major component of Lewy bodies, the neuropathological hallmarks of Parkinson's disease (PD). Missense mutations and multiplications of the SYN gene cause autosomal dominant inherited PD. Thus, SYN is implicated in the pathogenesis of PD. However, the mechanism whereby SYN promotes neurodegeneration remains unclear. Familial PD with SYN gene mutations are rare because the majority of PD is sporadic and emerging evidence indicates that sporadic PD may result from genetic and environmental risk factors including neuroinflammation. Hence, we examined the relationship between SYN dysfunction and neuroinflammation in mediating dopaminergic neurodegeneration in mice and dopaminergic neuronal cultures derived from wild-type SYN and mutant A53T SYN transgenic mice in a murine SYN-null (SYNKO) background (M7KO and M83KO, respectively). Stereotaxic injection of an inflammagen, lipopolysaccharide, into substantia nigra of these SYN genetically engineered mice induced similar inflammatory reactions. In M7KO and M83KO, but not in SYNKO mice, the neuroinflammation was associated with dopaminergic neuronal death and the accumulation of insoluble aggregated SYN as cytoplasmic inclusions in nigral neurons. Nitrated/oxidized SYN was detected in these inclusions and abatement of microglia-derived nitric oxide and superoxide provided significant neuroprotection in neuron-glia cultures from M7KO mice. These data suggest that nitric oxide and superoxide released by activated microglia may be mediators that link inflammation and abnormal SYN in mechanisms of PD neurodegeneration. This study advances understanding of the role of neuroinflammation and abnormal SYN in the pathogenesis of PD and opens new avenues for the discovery of more effective therapies for PD.

Topics: alpha-Synuclein; Analysis of Variance; Animals; Cell Count; Cells, Cultured; Coculture Techniques; Dopamine; Embryo, Mammalian; Humans; Inflammation; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation, Missense; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuroglia; Neurons; Nitric Oxide Synthase; Oxidative Stress

We analyzed whether genetic variation of alpha-synuclein modulates the extent of neuropathological changes in a population-based autopsied sample of 272 elderly Finns. None of the 11 markers was associated with the extent of neocortical beta-amyloid pathology. The intron 4 marker rs2572324 was associated with the extent of neurofibrillary pathology (p = 0.0006, permuted p = 0.004; Braak stages IV-VI vs 0-II). The same variant also showed a trend for association with neocortical Lewy-related pathology. These results suggest for the first time that variation of alpha-synuclein modulates neurofibrillary tau pathology and support the recent observations of an interaction of alpha-synuclein and tau in neurodegeneration.

Topics: Aged, 80 and over; alpha-Synuclein; Brain; Cohort Studies; DNA Mutational Analysis; Female; Genetic Markers; Genetic Predisposition to Disease; Genetic Testing; Genetic Variation; Humans; Lewy Bodies; Male; Neocortex; Nerve Degeneration; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; tau Proteins

Parkinson disease (PD) is characterized by dopaminergic neurodegeneration and intracellular inclusions of alpha-synuclein amyloid fibers, which are stable and difficult to dissolve. Whether inclusions are neuroprotective or pathological remains controversial, because prefibrillar oligomers may be more toxic than amyloid inclusions. Thus, whether therapies should target inclusions, preamyloid oligomers, or both is a critically important issue. In yeast, the protein-remodeling factor Hsp104 cooperates with Hsp70 and Hsp40 to dissolve and reactivate aggregated proteins. Metazoans, however, have no Hsp104 ortholog. Here we introduced Hsp104 into a rat PD model. Remarkably, Hsp104 reduced formation of phosphorylated alpha-synuclein inclusions and prevented nigrostriatal dopaminergic neurodegeneration induced by PD-linked alpha-synuclein (A30P). An in vitro assay employing pure proteins revealed that Hsp104 prevented fibrillization of alpha-synuclein and PD-linked variants (A30P, A53T, E46K). Hsp104 coupled ATP hydrolysis to the disassembly of preamyloid oligomers and amyloid fibers composed of alpha-synuclein. Furthermore, the mammalian Hsp70 and Hsp40 chaperones, Hsc70 and Hdj2, enhanced alpha-synuclein fiber disassembly by Hsp104. Hsp104 likely protects dopaminergic neurons by antagonizing toxic alpha-synuclein assemblies and might have therapeutic potential for PD and other neurodegenerative amyloidoses.

Topics: alpha-Synuclein; Amyloid; Animals; Brain; Disease Models, Animal; Dopamine; Heat-Shock Proteins; HSP40 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Humans; Models, Biological; Neurodegenerative Diseases; Parkinson Disease; Protein Binding; Rats

Dopaminergic neurodegeneration during Parkinson disease (PD) involves several pathways including proteasome inhibition, alpha-synuclein (alpha-syn) aggregation, mitochondrial dysfunction, and glutathione (GSH) depletion. We have utilized a systems biology approach and built a dynamic model to understand and link the various events related to PD pathophysiology. We have corroborated the modeling data by examining the effects of alpha-syn expression in the absence and presence of proteasome inhibition on GSH metabolism in dopaminergic neuronal cultures. We report here that the expression of the mutant A53T form of alpha-syn is neurotoxic and causes GSH depletion in cells after proteasome inhibition, compared to wild-type alpha-syn-expressing cells and vector control. Modeling data predicted that GSH depletion in these cells was due to ATP loss associated with mitochondrial dysfunction. ATP depletion elicited by combined A53T expression and proteasome inhibition results in decreased de novo synthesis of GSH via the rate-limiting enzyme gamma-glutamyl cysteine ligase. Based on these data and other recent reports, we propose a novel dynamic model to explain how the presence of mutated alpha-syn protein or proteasome inhibition may individually impact on mitochondrial function and in combination result in alterations in GSH metabolism via enhanced mitochondrial dysfunction.

Topics: Adenosine Triphosphate; alpha-Synuclein; Animals; Cells, Cultured; Dopamine; Glutathione; Humans; Mitochondria; Models, Biological; Mutation; Neurodegenerative Diseases; Neurons; Parkinson Disease; Proteasome Inhibitors; Rats

The increasing life expectancy will cause an increasing share for neurodegenerative and dementing illnesses in the total cost for health care. New developments such as the discovery of TDP-43 as disease protein have opened new viewpoints on frontotemporal dementias, as well as its relation to amyotrophic lateral sclerosis. As pathologists and neuropathologists we are committed to contributing to the progress of clinical diagnosis, which often proves difficult, by standardized post-mortem diagnosis. The diagnostic responsibility will increase with the development of new specific therapeutics and knowledge of contraindications such as the use of neuroleptics in patients suffering from Lewy body dementia. The Reference Center for Neurodegenerative Diseases of the German Society of Neuropathology and Neuroanatomy and the German Brain Bank (Brain-Net) at the Institute for Neuropathology, Ludwig-Maximilians-University Munich, are available for diagnosis in difficult or complex cases.

Topics: alpha-Synuclein; Alzheimer Disease; Autopsy; Brain; Diagnosis, Differential; DNA-Binding Proteins; Humans; Lewy Body Disease; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Pick Disease of the Brain; tau Proteins

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

Topics: alpha-Synuclein; Autonomic Nervous System; Dementia; Disease Progression; Dopamine; Humans; Neurodegenerative Diseases; Parkinson Disease; REM Sleep Behavior Disorder; Risk Factors; Substantia Nigra

Studies have shown that alpha-synuclein (alpha-syn) deposited in Lewy bodies in brain tissue from patients with Parkinson disease (PD) is extensively phosphorylated at Ser-129. We used recombinant Adeno-associated virus (rAAV) to overexpress human wild-type (wt) alpha-syn and two human alpha-syn mutants with site-directed replacement of Ser-129 to alanine (S129A) or to aspartate (S129D) in the nigrostriatal tract of the rat to investigate the effect of Ser-129 phosphorylation state on dopaminergic neuron pathology. Rats were injected with rAAV2/5 vectors in the substantia nigra pars compacta (SNc) on one side of the brain; the other side remained as a nontransduced control. The level of human wt or mutant alpha-syn expressed on the injected side was about four times the endogenous rat alpha-syn. There was a significant reduction of dopaminergic neurons in the SNc and dopamine (DA) and tyrosine hydroxylase (TH) levels in the striatum of all S129A-treated rats as early as 4 wk postinjection. Nigral DA pathology occurred more slowly in the wt-injected animals, but by 26 wk the wt alpha-syn group lost nigral TH neurons equivalent to the mutated S129A group at 8 wk. In stark contrast, we did not observe any pathological changes in S129D-treated animals. Therefore, the nonphosphorylated form of S129 exacerbates alpha-syn-induced nigral pathology, whereas Ser-129 phosphorylation eliminates alpha-syn-induced nigrostriatal degeneration. This suggests possible new therapeutic targets for Parkinson Disease.

Topics: alpha-Synuclein; Animals; Brain; Dependovirus; Disease Models, Animal; Dopamine; Humans; Lewy Bodies; Microscopy, Fluorescence; Neurodegenerative Diseases; Parkinson Disease; Phosphorylation; Rats; Recombinant Proteins; Serine; Tyrosine 3-Monooxygenase

Pathogenic aggregates of alpha-synuclein are thought to contribute to the development of Parkinson's disease. Inclusion bodies containing alpha-synuclein are present in Parkinson's disease and other neurodegenerative diseases, including Alzheimer's disease. Moreover, alpha-synuclein mutations are found in cases of familial Parkinson's disease, and transgenic overexpression of alpha-synuclein causes neurodegeneration in mice. The molecular mechanisms involved, however, remain incompletely understood. Here we show that, in transgenic mice, alpha-synuclein induced neurodegeneration involves activation of the ubiquitin/proteasome system, a massive increase in apolipoprotein E (ApoE) levels and accumulation of insoluble mouse Abeta. ApoE was not protective, but was injurious, as deletion of ApoE delayed the neurodegeneration caused by alpha-synuclein and suppressed the accumulation of Abeta. Our data reveal a molecular link between central pathogenic mechanisms implicated in Parkinson's disease and Alzheimer's disease and suggest that intracellular alpha-synuclein is pathogenic, at least in part, by activation of extracellular signaling pathways involving ApoE.

Topics: alpha-Synuclein; Alzheimer Disease; Amyloid beta-Peptides; Animals; Apolipoproteins E; Brain; Cell Death; Humans; Lewy Body Disease; Mice; Mice, Knockout; Mice, Transgenic; Nerve Degeneration; Neurodegenerative Diseases; Parkinson Disease; Peptides; Proteasome Endopeptidase Complex; Signal Transduction; Ubiquitin

Sensitive detection of alpha-synuclein (alpha-syn) pathology is important in the diagnosis of disorders like Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy and in providing better insights into the etiology of these diseases. Several monoclonal antibodies that selectively react with aggregated alpha-syn in pathological inclusions and reveal extensive and underappreciated alpha-syn pathology in the brains of diseased patients were previously reported by Duda et al. (Ann Neurol 52:205-210, 2002). We sought to characterize the specificity of some of these antibodies (Syn 505, Syn 506 and Syn 514); using C-terminal and N-terminal truncations of alpha-syn, all three antibodies were determined to require N-terminal epitopes that minimally comprise amino acids 2-4, but possibly extend to amino acid 12 of alpha-syn. The selectivity of these antibodies was further assessed using biochemical analysis of human brains and reactivity to altered recombinant alpha-syn proteins with duplication variants of amino acids 1-12. In addition, by expressing wild-type or a double mutant (E46K/A53T) of alpha-syn in cultured cells and by comparing their immunoreactivities to another antibody (SNL-4), which has a similar primary epitope, it was determined that Syn 505, Syn 506 and Syn 514 recognize conformational variants of alpha-syn that is enhanced by the presence of the double mutations. These studies indicate that antibodies Syn 505, Syn 506 and Syn 514 preferentially recognize N-terminal epitopes in complex conformations, consistent with the dramatic conformational change associated with the polymerization of alpha-synuclein into amyloid fibrils that form pathological inclusions.

Topics: alpha-Synuclein; Antibodies, Monoclonal; Antibody Specificity; Blotting, Western; Brain; Epitope Mapping; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Inclusion Bodies; Neurodegenerative Diseases; Transfection

Gathering evidence has associated activation of microglia with the pathogenesis of numerous neurodegenerative diseases of the central nervous system (CNS) such as Alzheimer's disease and Parkinson's disease. Microglia are the resident macrophages of the CNS whose functions include chemotaxis, phagocytosis, and secretion of a variety of cytokines and proteases. In this study, we examined the possibility that alpha-synuclein (alpha-syn), which is associated with the pathogenesis of Parkinson's disease, may affect the phagocytic function of microglia. We found that extracellular monomeric alpha-syn enhanced microglial phagocytosis in both a dose- and time-dependent manner, but beta- and gamma- syn did not. We also found that the N-terminal and NAC region of alpha-syn, especially the NAC region, might be responsible for the effect of alpha-syn on microglial phagocytosis. In contrast to monomeric alpha-syn, aggregated alpha-syn actually inhibited microglial phagocytosis. The different effects of monomeric and aggregated alpha-syn on phagocytosis might be related to their localization in cells. This study indicates that alpha-syn can modulate the function of microglia and influence inflammatory changes such as those seen in neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Cell Line; Cells, Cultured; Humans; Mice; Microglia; Neurodegenerative Diseases; Parkinson Disease; Phagocytosis; Protein Isoforms; Rats; Rats, Sprague-Dawley

The impaired ubiquitin-proteasome activity is believed to be one of the leading factors that contribute to Parkinson disease pathogenesis partially by causing alpha-synuclein aggregation. However, the relationship between alpha-synuclein aggregation and the impaired proteasome activity is yet unclear. In this study, we examined the effects of three soluble alpha-synuclein species (monomer, dimer, and protofibrils) on the degradation activity of the 26 S proteasome by reconstitution of proteasomal degradation using highly purified 26 S proteasomes and model substrates. We found that none of the three soluble alpha-synuclein species impaired the three distinct peptidase activities of the 26 S proteasome when using fluorogenic peptides as substrates. In striking contrast, alpha-synuclein protofibrils, but not monomer and dimer, markedly inhibited the ubiquitin-independent proteasomal degradation of unstructured proteins and ubiquitin-dependent degradation of folded proteins when present at 5-fold molar excess to the 26 S proteasome. Together these results indicate that alpha-synuclein protofibrils have a pronounced inhibitory effect on 26 S proteasome-mediated protein degradation. Because alpha-synuclein is a substrate of the proteasome, impaired proteasomal activity could further cause alpha-synuclein accumulation/aggregation, thus creating a vicious cycle and leading to Parkinson disease pathogenesis. Furthermore we found that alpha-synuclein protofibrils bound both the 26 S proteasome and substrates of the 26 S proteasome. Accordingly we propose that the inhibitory effect of alpha-synuclein protofibrils on 26 S proteasomal degradation might result from impairing substrate translocation by binding the proteasome or sequestrating proteasomal substrates by binding the substrates.

Topics: alpha-Synuclein; Animals; Cattle; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Protein Binding; Protein Folding; Solubility; Ubiquitin

Intraneuronal alpha-synuclein (alphaSYN) inclusions constitute the hallmark lesions of a number of neurodegenerative diseases, including Parkinson's disease and dementia with Lewy bodies. In a transgenic mouse model expressing mutant [A30P]alphaSYN under control of the pan-neuronal Thy1 promoter, motor impairment became significant beyond 17 months of age. Cognitive performance was measured in the Morris water maze and upon fear conditioning. At 4 months of age, transgenic mice performed like controls. However, performance in these tasks was significantly impaired in (Thy1)-h[A30P]alphaSYN mice at 12 months of age. After completion of the cognition tests, mice were sacrificed and the regional distribution of neuropathology was examined. In contrast to 4 months old animals, 12 months old transgenic mice showed alpha-synucleinopathy in several brain regions, including the central nucleus of the amygdala, which is involved in cognitive behavior of mice, and is susceptible to alphaSYN pathology in human patients. Thus, age-dependent fibrillization of alphaSYN in specific cortical regions concomitant with cognitive decline may reflect dementia with Lewy bodies in a transgenic mouse model.

Topics: Age Factors; alpha-Synuclein; Amygdala; Analysis of Variance; Animals; Avoidance Learning; Behavior, Animal; Cognition Disorders; Conditioning, Classical; Disease Models, Animal; Endopeptidase K; Fear; In Situ Hybridization; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Neurodegenerative Diseases; Neurologic Examination; Psychomotor Performance; Rotarod Performance Test

Immunohistochemical detection of protein components of pathological inclusions is widely used for neuropathological diagnosis of neurodegenerative disorders. However, different antibodies and antigen unmasking methods may account for variability between research studies and thus may affect diagnostic accuracy. Using two different antibodies raised against either a segment (184-200 aa) or the full length of human recombinant brain-specific tubulin polymerization promoting protein TPPP/p25, we immunohistochemically screened neurodegenerative disorders, both with and without pathological alpha-synuclein structures. We tested three different epitope unmasking methods, we applied laser confocal microscopy to evaluate double immunolabelling, and we compared the amount of structures exhibiting TPPP/p25 and alpha-synuclein immunoreactivity. We demonstrate that there are a variety of staining patterns depending on the epitope retrieval method and antibody used. The antibody raised against aa 184-200 segment of TPPP/p25 is better in immunolabelling the majority of alpha-synuclein immunopositive neuronal and glial pathological profiles detectable in Parkinson's disease, diffuse Lewy-body disease, and multiple system atrophy, in addition to immunostaining some extracellular huntingtin immunoreactive structures, lipofuscin, and neuromelanin particles. In contrast, the one raised against the full-length human recombinant TPPP/p25 is more suitable to immunodetect normal oligodendrocytes. Exposition of the segment aa 184-200 of TPPP/p25 in the aggregates of pathological inclusions renders this antibody a reliable marker of all types of alpha-synucleinopathies and suggests a role for TPPP/p25 in the aggregation process of some neurodegenerative conditions.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Brain; Chromobox Protein Homolog 5; Female; Humans; Male; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases

Topics: alpha-Synuclein; Brain Diseases; Humans; Inclusion Bodies; Lewy Bodies; Lewy Body Disease; Multiple System Atrophy; Neurodegenerative Diseases; Neuroglia; Parkinson Disease; Protein Kinases

Neurodegeneration with brain iron accumulation is a rare neurodegenerative disorder characterized by iron deposition in the basal ganglia and neuroaxonal dystrophy. Familial cases with mutations in the pantothenate kinase gene are associated with a specific phenotype. In contrast, sporadic cases are heterogeneous in their clinical presentation.. To describe an atypical case of sporadic late-onset neurodegeneration with brain iron accumulation.. Case report of a patient who presented with psychiatric features at age 22 years followed by progressive gait disturbance, extrapyramidal symptoms, epilepsy, and corticospinal tract involvement.. Magnetic resonance imaging showed iron deposition in the globus pallidus and substantia nigra. Cortical biopsy revealed Lewy bodies with predominant alpha-synuclein and less extensive tau-positive neurites.. Our findings in association with previously reported cases suggest that cortical neuritic and Lewy body pathology is a feature of atypical neurodegeneration with brain iron accumulation, clinically characterized by adult onset and psychiatric symptoms. These observations raise the possibility that these cases of atypical neurodegeneration with brain iron accumulation represent a distinct clinicopathological syndrome and suggest a molecular link between iron deposition and alpha-synuclein accumulation.

Topics: Adult; Age of Onset; alpha-Synuclein; Brain; Female; Humans; Iron; Lewy Bodies; Neurodegenerative Diseases; tau Proteins

1. Alpha-synuclein is known to play an important role in the pathogenesis of Parkinson's disease (PD). The pathogenicity of alpha-synuclein is related to its ability to form intraneuronal inclusions. The inclusions, which are found in brains of patients with PD and diffuse Lewy body disease consist partially of C-terminally truncated alpha-synuclein. This alpha-synuclein species has an increased ability to form aggregates compared to full length alpha-synuclein.2. We have used an adeno-associated virus (AAV) vector system to overexpress either C-terminally truncated or full length alpha-synuclein containing the A53T mutation, which have both been identified in brains of familial PD patients and transgenic mouse models. Dissociated mesencephalic neurons, cerebellar granule neurons, and organotypic midbrain slice cultures were infected with AAV containing the transgene under the control of the cytomegalovirus promoter.3. We demonstrate that viral overexpression of alpha-synuclein(A53T) leads to the formation of distorted neurites, intraneuritic swellings, and granular perikaryal deposits in cultured neurons. Our results indicate that these cell culture models may represent an early phase of PD reflecting pathologic neuritic alterations before significant neuronal cell loss occurs.

Topics: alpha-Synuclein; Animals; Animals, Newborn; Cells, Cultured; Dependovirus; Gene Expression Regulation; Green Fluorescent Proteins; Models, Biological; Neurodegenerative Diseases; Neurons; Organ Culture Techniques; Plaque, Amyloid; Rats; Rats, Wistar; Recombinant Fusion Proteins; Transduction, Genetic

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

Alpha-synuclein conformational modulation leading to fibrillation has been centrally implicated in Parkinson's disease. Previously, we have shown that alpha-synuclein has DNA binding property. In the present study, we have characterized the effect of DNA binding on the conformation and fibrillation kinetics of alpha-synuclein. It was observed that single-stranded circular DNA induce alpha-helix conformation in alpha-synuclein while plasmid supercoiled DNA has dual effect inducing a partially folded conformation and alpha-helix under different experimental conditions. Interestingly, alpha-synuclein showed a specificity for GC* nucleotide sequence in its binding ability to DNA. The aggregation kinetics data showed that DNA which induced partially folded conformation in alpha-synuclein promoted the fibrillation while DNA which induced alpha-helix delayed the fibrillation, indicating that the partially folded intermediate conformation is critical in the aggregation process. Further, the mechanism of DNA-induced folding/aggregation of alpha-synuclein was studied using effect of osmolytes on alpha-synuclein as a model system. Among the five osmolytes used, Glycerol, trimethylamine-N-oxide, Betaine, and Taurine induced partially folded conformation and in turn enhanced the aggregation of alpha-synuclein. The ability of DNA and osmolytes in inducing conformational transition in alpha-synuclein, indicates that two factors are critical in modulating alpha-synuclein folding: (i) electrostatic interaction as in the case of DNA, and (ii) hydrophobic interactions as in the case of osmolytes. The property of DNA inducing alpha-helical conformation in alpha-synuclein and inhibiting the fibrillation may be of significance in engineering DNA-chip based therapeutic approaches to PD and other amyloid disorders.

Topics: alpha-Synuclein; Animals; Betaine; Cattle; DNA; DNA, Circular; DNA, Single-Stranded; Glycerol; Methylamines; Models, Biological; Molecular Chaperones; Neurodegenerative Diseases; Protein Structure, Secondary; Sarcosine; Taurine

Recently, we showed that NUB1 is a synphilin-1-interacting protein and that NUB1, as well as synphilin-1, accumulates in Lewy bodies in Parkinson's disease (PD) and dementia with Lewy bodies (DLB), and glial cytoplasmic inclusions in multiple system atrophy (MSA). In this study, an investigation was further conducted to elucidate the immunohistochemical localization of NUB1 in various neurodegenerative disorders. In controls, anti-NUB1 antibody weakly immunolabeled neuronal perikarya. In PD and DLB, cortical and brainstem-type Lewy bodies, pale bodies and Lewy neurites were strongly immunolabeled with anti-NUB1. In MSA, NUB1 immunoreactivity was found in the intracytoplasmic inclusions of both neuronal and oligodendroglial cells, neuronal nuclear inclusions, and swollen neurites. No NUB1 immunoreactivity was found in a variety of other neuronal or glial inclusions in other disorders, including Alzheimer's disease, Pick's disease, progressive supranuclear palsy, corticobasal degeneration, motor neuron disease and triplet-repeat diseases. These findings indicate that the abnormal accumulation of NUB1 is specific for alpha-synucleinopathy lesions. However, yeast two-hybrid assay demonstrated that NUB1 did not directly interact with alpha-synuclein.

Topics: Adaptor Proteins, Signal Transducing; Aged; Aged, 80 and over; alpha-Synuclein; Humans; Immunohistochemistry; Inclusion Bodies; Lewy Bodies; Male; Middle Aged; Neurodegenerative Diseases; Oligodendroglia; Transcription Factors; Two-Hybrid System Techniques

Lewy-type pathology is a characteristic of a number of neurodegenerative disorders, including Parkinson's disease and dementia with Lewy bodies. Thus far, the definitive diagnosis of these dementias can only be confirmed at post-mortem. However, it is known that the loss of smell (anosmia) is an early symptom in patients who develop dementia, and the use of the smell test has been proposed as an early diagnostic procedure. The aim of this study was to understand further the extent of Lewy pathology in the olfactory system of patients with neurodegenerative disorders. Post-mortem tissue from 250 subjects was obtained from the OPTIMA brain bank. Five areas of the olfactory pathway were examined by immunolabelling for alpha-synuclein - a major component of Lewy pathology: the olfactory tract/bulb (n = 79), the anterior olfactory nucleus in the lateral olfactory gyrus (n = 193), the region of olfactory projection to the orbito-frontal cortex (n = 225), the hippocampus (n = 236) and the amygdala (n = 201). Results show that Lewy pathology affects different parts of the olfactory pathways differentially, suggesting a specific pattern of development of pathology. Clinical Parkinson's disease is most likely to be identified if the orbito-frontal cortex is affected, while the diagnosis is less likely if the pathology is restricted to the olfactory bulb or tract. These results suggest that pathology in the olfactory bulb and tract occurs prior to clinical signs of Parkinson's disease. Furthermore, the results presented here provide further evidence supporting the possible value of a smell test to aid the clinical diagnosis of neurodegenerative diseases.

Topics: Aged; alpha-Synuclein; Amygdala; Dementia; Hippocampus; Humans; Immunohistochemistry; Lewy Bodies; Lewy Body Disease; Neurodegenerative Diseases; Odds Ratio; Olfaction Disorders; Olfactory Bulb; Olfactory Pathways; Parkinson Disease

The nerve cell protein alpha-synuclein is important in Parkinson's disease and dementia with Lewy bodies, and its expression levels are directly linked to development of the diseases. Quantification of the plasma level of alpha-synuclein may therefore be important as a biomarker for disease susceptibility. We present a quantitative measurement of alpha-synuclein in the plasma of healthy control subjects in relation to their age using a novel enzyme-linked immunosorbent assay (ELISA). The plasma concentration among the 44 blood donors displayed a median of 5.6 microg/L (range 2.1-19.4 microg/L) with a narrow distribution (25 % and 75 % percentiles, 4.0 and 7.2 microg/L) and there was no correlation with age and gender. This narrow concentration range and the ease of measuring the quantitative ELISA support future investigations of plasma alpha-synuclein in relation to neurodegenerative diseases.

Topics: Adult; Age Factors; Aged; alpha-Synuclein; Analysis of Variance; Animals; Biomarkers; Blood Donors; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Neurodegenerative Diseases; Rabbits; Recombinant Proteins; Reference Values; Sensitivity and Specificity; Sex Factors

Topics: Aging; alpha-Synuclein; Animals; Autophagy; Cell Line, Tumor; Disease Models, Animal; Drosophila melanogaster; Humans; Neurodegenerative Diseases; Parkinson Disease; Rats; RNA Interference; Signal Transduction; Sirtuin 1; Sirtuin 2; Sirtuins; Transfection

Topics: alpha-Synuclein; Amyloid; Biochemistry; Humans; Magnetic Resonance Spectroscopy; Neurodegenerative Diseases; Protein Conformation; Protein Denaturation; Protein Folding; Protein Structure, Secondary; Proteins; Temperature

In Lewy body diseases and multiple system atrophy, alpha-synuclein is hyperphosphorylated at Ser129, suggesting a role in pathogenesis. Here, we report purification of the protein kinase in rat brain that phosphorylates Ser129 and its identification as casein kinase-2 (CK2). We show that most of the activity can be inhibited by heparin, an inhibitor of CK2. Phosphorylated Ser129 was detected in primary cultured neurons and inhibited by CK2 inhibitors. In some cases of Lewy body disease, CK2-like immunoreactivity was recovered in the sarkosyl-insoluble fraction, which was enriched in phosphorylated alpha-synuclein. Taken together, these findings suggest that CK2 may be involved in the hyperphosphorylation of alpha-synuclein in alpha-synucleinopathies.

Topics: Alanine; alpha-Synuclein; Animals; Brain; Casein Kinase II; Epitopes; Heparin; Humans; Mutation; Neurodegenerative Diseases; Phosphoserine; Rats; Tissue Culture Techniques

There is increasing evidence that aggregation of alpha-synuclein contributes to the functional and structural deterioration in the CNS of Parkinson's disease patients and transgenic animal models. alpha-Synuclein binds to various cellular proteins and aggregated alpha-synuclein species may affect their physiological function. In the present study, we used protein arrays spotted with 178 active human kinases for a large-scale analysis of the effects of recombinant alpha-synuclein on kinase activities. Incubation with globular alpha-synuclein oligomers significantly inhibited autophosphorylation of p21-activated kinase (PAK4) compared to treatment with monomeric alpha-synuclein or beta-synuclein. A concentration-dependent inhibition was also observed in a solution-based kinase assay. To show in vivo relevance, we analyzed brainstem protein extracts from alpha-synuclein (A30P) transgenic mice where accumulation of alpha-synuclein oligomers has been demonstrated. By immunoblotting using a phospho-specific antibody, we detected a significant decline in phosphorylation of LIM kinase 1, a physiological substrate for PAK4. Suppression of PAK activity by amyloid-beta oligomers has been reported in Alzheimer's disease. Thus, PAKs may represent a target for various neurotoxic protein oligomers, and signaling deficits may contribute to the behavioral defects in chronic neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; beta-Synuclein; Brain Stem; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Female; Inclusion Bodies; Lim Kinases; Macromolecular Substances; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Degeneration; Neurodegenerative Diseases; Neurons; p21-Activated Kinases; Phosphorylation; Polymers; Protein Array Analysis

Impaired transduction of transforming growth factor-beta signaling has recently been implicated in Alzheimer disease. Transforming growth factor-beta signals are transduced by Smads, which are phosphorylated and translocated to the nucleus, where they initiate gene transcription. In Alzheimer disease, neurofibrillary tangles sequester phosphorylated Smad 2/3 (pSmad2/3) and reduce its nuclear translocation. We have now investigated the relationship between pSmad2/3 and phospho-tau in 3 other tauopathies, Pick disease, progressive supranuclear palsy, and corticobasal degeneration, and in 2 alpha-synucleinopathies, dementia with Lewy bodies and multiple system atrophy. In Pick disease, progressive supranuclear palsy, and corticobasal degeneration, pSmad2/3 was demonstrated in neuronal and glial nuclei but also colocalized with cytoplasmic tau inclusions. No pSmad2/3 was detected in glial cytoplasmic inclusions in multiple system atrophy or in Lewy bodies in dementia with Lewy bodies. Our data indicate that phospho-tau but not alpha-synuclein cytoplasmic inclusions bind pSmad2/3. The preservation of neuronal nuclear pSmad2/3 in Pick disease, progressive supranuclear palsy, and corticobasal degeneration suggests that cytoplasmic sequestration of pSmad2/3 is likely to have less impact on transforming growth factor-beta signal transduction in these diseases than in Alzheimer disease.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Blotting, Western; Brain; Female; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Inclusion Bodies; Lewy Body Disease; Male; Multiple System Atrophy; Neurodegenerative Diseases; Phosphorylation; Pick Disease of the Brain; Protein Transport; Smad Proteins; Supranuclear Palsy, Progressive; tau Proteins

A tissue microarray (TMA) was constructed using 47 neurodegenerative diseases (NDD), including Alzheimer's disease (AD; n = 30) and non-AD NDD (n = 17), and from seven controls. For validation of the methodology, the following three immunostains were used. Tau and beta-amyloid-related pathologies were more significantly recognized in tauopathies/AD compared to non-tauopathies/controls, and these results were comparable to the assessment of the whole brain sections. But no alpha-synuclein pathologies were observed despite five cases of dementia with Lewy bodies. It was concluded that the TMA technique is useful for NDD with diffuse pathological processes but not for those with patchy and occasional lesions or in early stages. Growth-associated protein (GAP)-43 and calretinin were also immunostained. A significant reduction in GAP-43 expression was seen in the frontal lobe and hippocampus in AD compared to non-AD cases, but not in other areas. No significant difference in number of anticalretinin immunoreactive neurons or in density of immunoreactive neurites was observed between any of the NDD and controls, which may indicate that calretinin-positive neurons are spared in the degenerative process. These results are compatible with the previous studies. These analyses were performed rapidly in a large number of cases using a single slide under uniform staining conditions.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Brain; Calbindin 2; Female; GAP-43 Protein; Humans; Immunohistochemistry; Male; Middle Aged; Neurodegenerative Diseases; S100 Calcium Binding Protein G; tau Proteins; Tissue Array Analysis

Hallervorden-Spatz syndrome (HSS) is a heterogeneous clinicopathological disorder currently included within the broader title of neurodegeneration with brain iron accumulation (NBIA). The classic histological hallmarks of HSS are axonal spheroids and excessive iron-containing granules accompanied by neuronal loss and gliosis in the globus pallidus and substantia nigra reticulata. In the modern literature, attention has been drawn to the co-occurrence of two other histological markers: Lewy bodies mainly composed of abnormal alpha-synuclein, and neurofibrillary tangles due to hyperphosphorilated tau aggregation. Discrepancies exist regarding the importance of these molecular changes and its relevance for the nosology of HSS. Most authors have emphasized the importance of the Lewy body-like pathology, favoring the inclusion of HSS within the alpha-synucleinopathies. We report on a case of late-onset HSS, with the typical histological findings restricted to the basal ganglia and cerebellum in which tau pathology was exceedingly more abundant than alpha-synuclein pathology. This case contributes to the increasing evidence about the heterogeneity of HSS. We favor the view that the molecular changes and the protein misfolding underlying the Lewy body and tangle formation in HSS/NBIA are secondary to the main pathological process and should not be taken as the basis for its nosological classification.

Topics: alpha-Synuclein; Axons; Basal Ganglia; Brain; Brain Stem; Diagnosis, Differential; Humans; Inclusion Bodies; Iron; Lewy Bodies; Male; Middle Aged; Myelin Sheath; Neurodegenerative Diseases; Neurofibrillary Tangles; Pantothenate Kinase-Associated Neurodegeneration; Protein Folding; Spheroids, Cellular; tau Proteins; Tauopathies; Thalamic Nuclei

Sumoylation is an important post-translational modification that provides a rapid and reversible means for controlling the activity, subcellular localization, and stability of target proteins. We have examined the covalent attachment of the small ubiquitin-like modifier (SUMO) proteins to tau and alpha-synuclein, two natively unfolded proteins that define several neurodegenerative diseases. Both brain proteins were preferentially modified by SUMO1, as compared with SUMO2 or SUMO3. Tau contains two SUMO consensus sequences, and mutational analyses identified Lys(340) as the major sumoylation site. Although both tau and alpha-synuclein are targets for proteasomal degradation, only tau sumoylation was affected by inhibitors of the proteasome pathway. Tau is a microtubule-associated protein, whose ability to bind and stabilize microtubules is negatively regulated by phosphorylation. Treatment with the phosphatase inhibitor, okadaic acid, or the microtubule depolymerizing drug, colchicine, up-regulated tau sumoylation. This suggests that SUMO modification may preferentially target a free soluble pool of the substrate. These findings revealed a new, possibly regulatory, modification of tau and alpha-synuclein that may also have implications for their pathogenic roles in neurodegenerative diseases.

Topics: alpha-Synuclein; Blotting, Western; Cell Line; Epitopes; Humans; Lysine; Microtubules; Neurodegenerative Diseases; Phosphorylation; Plasmids; Proteasome Endopeptidase Complex; Protein Binding; Protein Denaturation; Protein Folding; Protein Structure, Tertiary; Small Ubiquitin-Related Modifier Proteins; SUMO-1 Protein; tau Proteins; Transfection; Ubiquitin; Ubiquitins

Heat shock proteins (Hsps) facilitate refolding of denatured polypeptides, but there is limited understanding about their roles in neurodegenerative diseases characterized by misfolded proteins. Because Parkinson's disease (PD), dementia with Lewy bodies, and multiple system atrophy are alpha-synucleinopathies characterized by filamentous alpha-synuclein (alpha-syn) inclusions, we assessed which Hsps might be implicated in these disorders by examining human brain samples, transgenic mouse models, and cell culture systems. Light and electron microscopic multiple-label immunohistochemistry showed Hsp90 was the predominant Hsp examined that co-localized with alpha-syn in Lewy bodies, Lewy neurites, and glial cell inclusions and that Hsp90 co-localized with alpha-syn filaments of Lewy bodies in PD. Hsp90 levels were most predominantly increased in PD brains, which correlated with increased levels of insoluble alpha-syn. These alterations in Hsp90 were recapitulated in a transgenic mouse model of PD-like alpha-syn pathologies. Cell culture studies also revealed that alpha-syn co-immunoprecipitated preferentially with Hsp90 and Hsc70 relative to other Hsps, and exposure of cells to proteasome inhibitors resulted in increased levels of Hsp90. These data implicate predominantly Hsp90 in the formation of alpha-syn inclusions in PD and related alpha-synucleinopathies.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Animals; Brain; Brain Chemistry; Female; HSP90 Heat-Shock Proteins; Humans; Inclusion Bodies; Male; Mice; Mice, Transgenic; Middle Aged; Neurodegenerative Diseases; Neurons; Oligodendroglia; Proteasome Inhibitors; Substantia Nigra; Ubiquitin; Up-Regulation

We constructed tissue microarray (TMA) blocks containing post-mortem human brain tissue from subjects with clinically and neuropathologically verified Alzheimer's disease (AD), corticobasal degeneration (CBD), progressive supranuclear palsy, Lewy body disease, multisystem atrophy (MSA) as well as an age matched control. Fifteen donor blocks were merged into two TMA blocks containing 72, 2-mm punch core samples with representative brain regions generally affected in degenerative disorders. Hyperphosphorylated-gamma, alpha-synuclein and beta-amyloid-related pathologies were estimated. The diseases were easily recognized by evaluating the two TMA sections and the results assessing TMA sections were comparable with the assessment of the whole brain sections. The assessment of TMA sections revealed concomitant multifocal alpha-synuclein pathology in AD, mild tau-involvement in the case of MSA and a slight AD-type pathology in the case of CBD. These findings emphasize the importance of searching for a variety of pathologies in "the whole brain" rather than restricting the examination to a few vulnerable regions. Furthermore, the TMA methodology clearly reduced the number of sections needed for evaluating the whole brain, it increased the amount of research material generated and furthermore no detailed neuroanatomical knowledge was required for assessment of data.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Biopsy; Brain; Dissection; Female; Humans; Immunohistochemistry; Male; Microarray Analysis; Microtomy; Middle Aged; Neurodegenerative Diseases; Pathology; Plaque, Amyloid; Reproducibility of Results; Sample Size; tau Proteins; Tauopathies

To study the role of atypical protein kinase C (aPKC) in neurodegenerative disease, we investigated the distribution of PKCiota/lambda, an aPKC isoform, in a variety of tauopathies and alpha-synucleinopathies. Immunohistochemical study revealed PKCiota/lambda within tau-positive neurofibrillary inclusions in Alzheimer disease (AD), progressive supranuclear palsy, corticobasal degeneration (CBD), and Pick disease (PiD), within alpha-synuclein-positive Lewy bodies in idiopathic Parkinson disease and dementia with Lewy bodies, as well as within glial inclusions in multisystem atrophy. We also observed PKCiota/lambda label of actin-rich Hirano bodies in AD, PiD, and elderly individuals. Double immunolabeling and fluorescence resonance energy transfer demonstrated close physical association between PKCiota/lambda and phospho-tau or alpha-synuclein in some neurofibrillary tangles and Lewy bodies. Furthermore, PKCiota/lambda colocalized with p62, a chaperone protein that binds to both aPKC and ubiquitin, in most of these inclusions. PKCiota/lambda also closely associated with the inactivated form of glycogen synthase kinase-3beta, GSK-3beta[ser9]. Together, these findings suggest that PKCiota/lambda may play a role in common mechanisms involving the pathogenesis of neurodegenerative disease.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Brain; Female; Humans; Immunohistochemistry; Inclusion Bodies; Isoenzymes; Male; Middle Aged; Neurodegenerative Diseases; Protein Kinase C; tau Proteins

Many neurodegenerative disorders, such as Parkinson disease, exhibit inclusion bodies containing ubiquitinated proteins. The mechanisms implicated in this aberrant protein deposition remain elusive. In these disorders signs of inflammation are also apparent in the affected central nervous system areas. We show that prostaglandin J2 (PGJ2), an endogenous product of inflammation, disrupts the cytoskeleton in neuronal cells. Furthermore, PGJ2 perturbed microtubule polymerization in vitro and decreased the number of free sulfhydryl groups on tubulin cysteines. A direct effect of PGJ2 on actin was not apparent, although actin filaments were altered in cells treated with PGJ2. This cyclopentenone prostaglandin triggered endoplasmic reticulum (ER) collapse and the redistribution of ER proteins, such as calnexin and catechol-O-methyltransferase, into a large centrosomal aggregate containing ubiquitinated proteins and alpha-synuclein. The PGJ2-dependent cytoskeletal rearrangement paralleled the development of the large centrosomal aggregate. Both of these events were replicated by treating cells with colchicine, which disrupts the microtubule/ER network, but not with brefeldin A, which impairs ER/Golgi transport. PGJ2 also perturbed 26 S proteasome assembly and activity, which preceded the accumulation of ubiquitinated proteins as detergent/salt-insoluble aggregates. Our data support a mechanism by which, upon PGJ2 treatment, cytoskeleton/ER collapse coincides with the relocation of ER proteins, other potentially neighboring proteins, and ubiquitinated proteins into centrosomal aggregates. Development of these large perinuclear aggregates is associated with disruption of the microtubule/ER network. This aberrant protein deposition, triggered by a product of inflammation, may be common to other compounds that disrupt microtubules and induce protein aggregation, such as MPP+ and rotenone, found to be associated with neurodegeneration.

Topics: Actins; alpha-Synuclein; Cell Line, Tumor; Centrosome; Cyclopentanes; Cytoskeleton; Endoplasmic Reticulum; Humans; Inflammation; Kinetics; Microtubules; Neurodegenerative Diseases; Prostaglandin D2; Proteasome Endopeptidase Complex; Protein Binding; Ubiquitin

The 20 S proteasome is a ubiquitous, barrel-shaped protease complex responsible for most of cellular proteolysis, and its reduced activity is thought to be associated with accumulations of aberrant or misfolded proteins, resulting in a number of neurodegenerative diseases, including amyotrophic lateral sclerosis, spinal and bulbar muscular atrophy, Parkinson disease, and Alzheimer disease. The 20 S proteasomes of archaebacteria (archaea) are structurally simple and proteolytically powerful and thought to be an evolutionary precursor to eukaryotic proteasomes. We successfully reproduced the archaeal proteasome in a functional state in mammalian cells, and here we show that the archaeal proteasome effectively accelerated species-specific degradation of mutant superoxide dismutase-1 and the mutant polyglutamine tract-extended androgen receptor, causative proteins of familial amyotrophic lateral sclerosis and spinal and bulbar muscular atrophy, respectively, and reduced the cellular toxicities of these mutant proteins. Further, we demonstrate that archaeal proteasome can also degrade other neurodegenerative disease-associated proteins such as alpha-synuclein and tau. Our study showed that archaeal proteasomes can degrade aggregation-prone proteins whose toxic gain of function causes neurodegradation and reduce protein cellular toxicity.

Topics: alpha-Synuclein; Androgen Receptor Antagonists; Animals; Archaeal Proteins; Cell Line; Cell Line, Tumor; Humans; Hydrolysis; Methanosarcina; Mice; Neurodegenerative Diseases; Proteasome Endopeptidase Complex; Protein Subunits; Receptors, Androgen; Superoxide Dismutase; Superoxide Dismutase-1

G-protein coupled receptor kinases (GRKs) constitute a serine/threonine kinase family playing a major role in agonist-induced phosphorylation and desensitization of G-protein coupled receptors. Recently, GRK2 and GRK5 have been demonstrated to phosphorylate alpha-synuclein (Ser129) and other synuclein isoforms. We studied colocalization of GRK2, GRK5, alpha-synuclein, and tau in neurodegenerative disorders characterized by fibrillary tau inclusions and/or alpha-synuclein-enriched Lewy bodies. We found that Lewy bodies were negative for both GRK2 and GRK5 in Lewy body disease (LBD) and LBD mixed with Alzheimer disease (AD + LBD). Instead, GRK2 but not GRK5 colocalized with 40% to 50% of neurofibrillary tangles in AD + LBD and AD brains. In disorders with less prominent alpha-synucleinopathy, neuronal and glial fibrillary tau deposits known to contain distinct subsets of tau isoforms were also positive for GRK2. These deposits included tufted astrocytes and coiled bodies in progressive supranuclear palsy, astrocytic plaques in corticobasal degeneration, and Pick bodies in Pick disease. In addition, paired helical filaments isolated from AD and AD + LBD brains were found to immunogold-label for GRK2, suggesting that GRK2 could be a potential tau kinase associated with fibrillary tau. Our studies indicate that GRK2 is a novel component of neuronal and glial fibrillary tau deposits with no preference in tau isoform binding. GRK2 may play a role in hyperphosphorylation of tau in tauopathies.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; beta-Adrenergic Receptor Kinases; Brain; Female; G-Protein-Coupled Receptor Kinase 2; G-Protein-Coupled Receptor Kinase 5; Humans; Lewy Bodies; Lewy Body Disease; Male; Neurodegenerative Diseases; Neurofibrillary Tangles; Neuroglia; Neurons; Phosphorylation; Pick Disease of the Brain; Protein Serine-Threonine Kinases; Supranuclear Palsy, Progressive; tau Proteins

Topics: alpha-Synuclein; Biomarkers; Diagnosis, Differential; Humans; Neurodegenerative Diseases; REM Sleep Behavior Disorder

Aggregation of the nerve cell protein alpha-synuclein is a characteristic of the common neurodegenerative alpha-synucleinopathies like Parkinson's disease and Lewy body dementia, and it plays a direct pathogenic role as demonstrated by early onset diseases caused by mis-sense mutations and multiplication of the alpha-synuclein gene. We investigated the existence of alpha-synuclein pro-aggregatory brain proteins whose dysregulation may contribute to disease progression, and we identified the brain-specific p25alpha as a candidate that preferentially binds to alpha-synuclein in its aggregated state. Functionally, purified recombinant human p25alpha strongly stimulates the aggregation of alpha-synuclein in vitro as demonstrated by thioflavin-T fluorescence and quantitative electron microscopy. p25alpha is normally only expressed in oligodendrocytes in contrast to alpha-synuclein, which is normally only expressed in neurons. This expression pattern is changed in alpha-synucleinopathies. In multiple systems atrophy, degenerating oligodendrocytes displayed accumulation of p25alpha and dystopically expressed alpha-synuclein in the glial cytoplasmic inclusions. In Parkinson's disease and Lewy body dementia, p25alpha was detectable in the neuronal Lewy body inclusions along with alpha-synuclein. The localization in alpha-synuclein-containing inclusions was verified biochemically by immunological detection in Lewy body inclusions purified from Lewy body dementia tissue and glial cytoplasmic inclusions purified from tissue from multiple systems atrophy. We suggest that p25alpha plays a pro-aggregatory role in the common neurodegenerative disorders hall-marked by alpha-synuclein aggregates.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Brain; Cattle; Cells, Cultured; Cloning, Molecular; Cytoplasm; Dementia; Humans; Lewy Bodies; Molecular Sequence Data; Nerve Tissue Proteins; Neurites; Neurodegenerative Diseases; Neuroglia; Peptide Fragments; Protein Binding; Rats; Synucleins; Trypsin

Topics: Aged; alpha-Synuclein; Animals; Brain; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins

Increasing evidence indicates that many peptides and proteins can be converted in vitro into highly organised amyloid structures, provided that the appropriate experimental conditions can be found. In this work, we define intrinsic propensities for the aggregation of individual amino acids and develop a method for identifying the regions of the sequence of an unfolded peptide or protein that are most important for promoting amyloid formation. This method is applied to the study of three polypeptides associated with neurodegenerative diseases, Abeta42, alpha-synuclein and tau. In order to validate the approach, we compare the regions of proteins that are predicted to be most important in driving aggregation, either intrinsically or as the result of mutations, with those determined experimentally. The knowledge of the location and the type of the "sensitive regions" for aggregation is important both for rationalising the effects of sequence changes on the aggregation of polypeptide chains and for the development of targeted strategies to combat diseases associated with amyloid formation.

Topics: alpha-Synuclein; Amino Acid Substitution; Amyloid beta-Peptides; Amyloidosis; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Nerve Tissue Proteins; Neurodegenerative Diseases; Peptide Fragments; Peptides; Protein Binding; Protein Structure, Quaternary; Protein Structure, Secondary; Synucleins; tau Proteins

Neuronal intranuclear inclusion disease (NIID) is a rare and heterogeneous group of slowly progressive neurodegenerative disorders characterized by the widespread presence of eosinophilic neuronal intranuclear inclusions (NII) accompanied by a more restricted pattern of neuronal loss. We report here the pathologic findings in a 13-year-old boy who died after a 6-year clinical history of progressive ataxia, extrapyramidal manifestations, and lower motor neuron abnormalities. Histological evaluation of the brain revealed widespread NII in most neurons. Marked loss of cerebellar Purkinje cells and neurons in the dentate nucleus, red nucleus, and spinal cord anterior horns was accompanied by a modest astrocytosis. Because of the abundance of NII and the absence of a relationship between NII and neuronal loss or microglial activation, we conclude that loss of cerebellar, brainstem, and spinal cord neurons reflects selective neuronal vulnerability. NII were immunoreactive for ubiquitin, glucocorticoid receptor, and SUMO-1, a small, ubiquitin-like protein purportedly involved in protein transport and gene transcription. NII were non-reactive for polyglutamine (1C2), TATA binding protein, promyelocytic leukemia protein, heat shock protein 90, tau, alpha-synuclein, neurofilament, and beta amyloid. The moderate ubiquitin and strong SUMO-1 staining of NII in juvenile cases is the reverse of the pattern noted in adult diseases, suggesting the two age groups are pathogenically distinct. We suggest that juvenile NIID is a spinocerebellar brainstem ataxic disease possibly related to an abnormality in SUMOylation.

Topics: Adolescent; alpha-Synuclein; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Brain; Crystallins; Glial Fibrillary Acidic Protein; HSP90 Heat-Shock Proteins; Humans; Immunohistochemistry; Intranuclear Inclusion Bodies; Male; Microscopy, Electron, Transmission; Neoplasm Proteins; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofilament Proteins; Neurons; Nuclear Proteins; Peptides; Promyelocytic Leukemia Protein; Receptors, Glucocorticoid; Synucleins; tau Proteins; Transcription Factors; Tumor Suppressor Proteins; Ubiquitin

Alzheimer's disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and dementia with Lewy bodies (DLB) are diseases associated with the accumulation of tau or alpha-synuclein. In AD, beta-amyloid (Abeta)-associated caspase activation and cleavage of tau at Asp421 (DeltaTau) may be an early step in neurofibrillary tangle (NFT) formation. To examine whether DeltaTau accumulates in other diseases not characterized by extracellular Abeta accumulation, we examined PiD, PSP, and CBD cases in comparison to those without extensive tau accumulation including frontotemporal lobar degeneration without Pick bodies (FTLD) and control cases. Additionally, we studied DeltaTau accumulation in DLB cases associated with intracellular alpha-synuclein. DeltaTau was observed in all disease cases except non-PiD FTLD and controls. These results demonstrate that the accumulation of DeltaTau may represent a common pathway associated with abnormal accumulation of intracellular tau or alpha-synuclein and may be relatively less dependent on the extracellular accumulation of Abeta in non-AD dementias.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Caspases; Female; Humans; Immunohistochemistry; Inclusion Bodies; Male; Microscopy, Confocal; Middle Aged; Neurodegenerative Diseases; Neurofibrillary Tangles; tau Proteins

Recent studies have begun to investigate the role of agrin in brain and suggest that agrin's function likely extends beyond that of a synaptogenic protein. Particularly, it has been shown that agrin is associated with the pathological lesions of Alzheimer's disease (AD) and may contribute to the formation of beta-amyloid (Abeta) plaques in AD. We have extended the analysis of agrin's function in neurodegenerative diseases to investigate its role in Parkinson's disease (PD). Alpha-synuclein is a critical molecular determinant in familial and sporadic PD, with the formation of alpha-synuclein fibrils being enhanced by sulfated macromolecules. In the studies reported here, we show that agrin binds to alpha-synuclein in a heparan sulfate-dependent (HS-dependent) manner, induces conformational changes in this protein characterized by beta-sheet structure, and enhances insolubility of alpha-synuclein. We also show that agrin accelerates the formation of protofibrils by alpha-synuclein and decreases the half-time of fibril formation. The association of agrin with PD lesions was also explored in PD human brain, and these studies shown that agrin colocalizes with alpha-synuclein in neuronal Lewy bodies in the substantia nigra of PD brain. These studies indicate that agrin is capable of accelerating the formation of insoluble protein fibrils in a second common neurodegenerative disease. These findings may indicate shared molecular mechanisms leading to the pathophysiology in these two neurodegenerative disorders.

Topics: Agrin; alpha-Synuclein; Alzheimer Disease; Animals; Antibodies, Monoclonal; Brain; Cell Death; Chickens; Circular Dichroism; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Heparitin Sulfate; Humans; Immunoblotting; Immunohistochemistry; Lewy Bodies; Microscopy, Electron, Transmission; Neurodegenerative Diseases; Neurons; Parkinson Disease; Prions; Protein Binding; Protein Conformation; Recombinant Proteins; Solubility; Substantia Nigra; Synucleins; Time Factors

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

The polypeptides involved in amyloidogenesis may be globular proteins with a defined 3D-structure or natively unfolded proteins. The first class includes polypeptides such as beta2-microglobulin, lysozyme, transthyretin or the prion protein, whereas beta-amyloid peptide, amylin or alpha-synuclein all belong to the second class. Recent studies suggest that specific regions in the proteins act as "hot spots" driving aggregation. This should be especially relevant for natively unfolded proteins or unfolded states of globular proteins as they lack significant secondary and tertiary structure and specific intra-chain interactions that can mask these aggregation-prone regions. Prediction of such sequence stretches is important since they are potential therapeutic targets.. In this study we exploited the experimental data obtained in an in vivo system using beta-amyloid peptide as a model to derive the individual aggregation propensities of natural amino acids. These data are used to generate aggregation profiles for different disease-related polypeptides. The approach detects the presence of "hot spots" which have been already validated experimentally in the literature and provides insights into the effect of disease-linked mutations in these polypeptides.. The proposed method might become a useful tool for the future development of sequence-targeted anti-aggregation pharmaceuticals.

Topics: alpha-Synuclein; Amyloid beta-Peptides; beta 2-Microglobulin; Humans; Insulin; Models, Molecular; Muramidase; Mutation; Neurodegenerative Diseases; Peptides; Prealbumin; Prions; Protein Binding; Protein Conformation; Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins

The deposition of alpha-syn (alpha-synuclein) fibrils in Lewy bodies is a characteristic feature of individuals with neurodegenerative disorders. A peptide comprising the central residues 71-82 of alpha-syn [alpha-syn(71-82)] is capable of forming beta-sheet-rich, amyloid-like fibrils with similar morphologies to fibrils of the full-length protein, providing a useful model of pathogenic alpha-syn fibrils that is suitable for detailed structural analysis. We have studied the morphology and gross structural features of alpha-syn(71-82) fibrils formed under different conditions in order to obtain reliable conditions for producing fibrils for further structural investigations. The results indicate that the rate of aggregation and the morphology of the fibrils formed are sensitive to pH and temperature.

Topics: alpha-Synuclein; Amyloid; Neurodegenerative Diseases; Peptide Fragments; Protein Binding; Protein Conformation; Protein Folding

A unifying feature of many neurodegenerative disorders is the accumulation of polyubiquitinated protein inclusions in dystrophic neurons, e.g. containing alpha-synuclein, which is suggestive of an insufficient proteasomal activity. We demonstrate that alpha-synuclein and 20 S proteasome components co-localize in Lewy bodies and show that subunits from 20 S proteasome particles, in contrast to subunits of the 19 S regulatory complex, bind efficiently to aggregated filamentous but not monomeric alpha-synuclein. Proteasome binding to insoluble alpha-synuclein filaments and soluble alpha-synuclein oligomers results in marked inhibition of its chymotrypsin-like hydrolytic activity through a non-competitive mechanism that is mimicked by model amyloid-Abeta peptide aggregates. Endogenous ligands of aggregated alpha-synuclein like heat shock protein 70 and glyceraldehyde-6-phosphate dehydrogenase bind filaments and inhibit their anti-proteasomal activity. The inhibitory effect of amyloid aggregates may thus be amenable to modulation by endogenous chaperones and possibly accessible for therapeutic intervention.

Topics: alpha-Synuclein; Chymotrypsin; Cysteine Endopeptidases; Dose-Response Relationship, Drug; Erythrocytes; HSP70 Heat-Shock Proteins; Humans; Immunohistochemistry; Lewy Bodies; Ligands; Microscopy, Confocal; Microscopy, Electron; Multienzyme Complexes; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Proteasome Endopeptidase Complex; Protein Binding; Recombinant Proteins; Synucleins; Time Factors

Cytoplasmic deposition of alpha-synuclein aggregates is a common pathological feature of many neurodegenerative diseases. Strong evidence for the causative role of alpha-synuclein in these disorders is provided by genetic linkage between this gene and familial Parkinson's disease and by neurodegeneration in transgenic animals that overexpress this protein. In particular, it has been hypothesized that the accumulation of nonfibrillar oligomers of alpha-synuclein, which serve as intermediates for fibrillar inclusion body formation, causes neurodegeneration. However, little is known about how cells handle potentially toxic protein aggregates. Here we demonstrate that cells are capable of clearing preformed alpha-synuclein aggregates via the lysosomal degradation pathway. Consequently, blocking this pathway causes the accumulation of the aggregates in non-neuronal cells, differentiated neuroblastoma cells, and primary cortical neurons. This aggregate clearance occurs in an aggregation stage-specific manner; oligomeric intermediates are susceptible to clearance, whereas mature fibrillar inclusion bodies are not. Neutralization of the acidic compartments leads to the accumulation of alpha-synuclein aggregates and exacerbates alpha-synuclein toxicity in postmitotic neuronal cells, suggesting that the accumulation of oligomeric intermediates may be an important event leading to alpha-synuclein-mediated cell death. These results suggest that enhancing lysosomal function may be a potential therapeutic strategy to halt or even prevent the pathogenesis of Parkinson's disease and other Lewy body diseases.

Topics: alpha-Synuclein; Animals; Cell Compartmentation; Cell Death; Cell Survival; Cells, Cultured; Chlorocebus aethiops; COS Cells; Dimethyl Sulfoxide; Enzyme Inhibitors; Gene Expression; Humans; Inclusion Bodies; Lysosomes; Macromolecular Substances; Nerve Tissue Proteins; Neuroblastoma; Neurodegenerative Diseases; Neurons; Rats; Rats, Sprague-Dawley; Rotenone; Synucleins; Time Factors; Transfection; Uncoupling Agents

Intracytoplasmic filamentous aggregates, such as neurofibrillary tangles in Alzheimer's disease and Lewy bodies in Parkinson's disease, are composed of the proteins tau and alpha-synuclein, respectively. These pathological inclusions are linked directly to the etiology and mechanisms of disease in a wide spectrum of neurodegenerative disorders, termed 'tauopathies' and 'synucleinopathies'. Emerging evidence indicates that there is frequent overlap of the pathological and clinical features of patients with tauopathies and synucleinopathies, thereby re-enforcing the notion that these disorders might be linked mechanistically. Indeed, several lines of investigation suggest that tau and alpha-synuclein might constitute a unique class of unstructured proteins that assemble predominantly into homopolymeric (rather than heteropolymeric) fibrils, which deposit mainly in separate amyloid inclusions, but occasionally deposit together. Thus, the ability of tau and alpha-synuclein to affect each other directly or indirectly might contribute to the overlap in the clinical and pathological features of tauopathies and synucleinopathies.

Topics: alpha-Synuclein; Amyloid; Amyloidosis; Animals; Brain; Humans; Inclusion Bodies; Models, Neurological; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Neurons; Synucleins; tau Proteins

Presenilin-1 null mutation (PS1 -/-) in mice is associated with morphological alterations and defects in cleavage of transmembrane proteins. Here, we demonstrate that PS1 deficiency also leads to the formation of degradative vacuoles and to the aberrant translocation of presynaptic alpha- and beta-synuclein proteins to these organelles in the perikarya of primary neurons, concomitant with significant increases in the levels of both synucleins. Stimulation of autophagy in control neurons produced a similar mislocalization of synucleins as genetic ablation of PS1. These effects were not the result of the loss of PS1 gamma-secretase activity; however, dysregulation of calcium channels in PS1 -/- cells may be involved. Finally, colocalization of alpha-synuclein and degradative organelles was observed in brains from patients with the Lewy body variant of AD. Thus, aberrant accumulation of alpha- and beta-synuclein in degradative organelles are novel features of PS1 -/- neurons, and similar events may promote the formation of alpha-synuclein inclusions associated with neurodegenerative diseases.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid Precursor Protein Secretases; Animals; Antigens, CD; Aspartic Acid Endopeptidases; Autophagy; beta-Synuclein; Brain; Calcium Channels; Cells, Cultured; Endopeptidases; Female; Humans; Inclusion Bodies; Lysosomal Membrane Proteins; Lysosomes; Male; Membrane Proteins; Mice; Mice, Knockout; Microscopy, Electron; Middle Aged; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Presenilin-1; Protein Transport; Synucleins; Up-Regulation; Vacuoles

Many of the proposed physiological functions of alpha-synuclein, a protein involved in the pathogenesis of Parkinson's disease, are related to its ability to interact with phospholipids. To better understand the conformational changes that occur upon membrane binding of monomeric alpha-synuclein, we performed EPR analysis of 47 singly labeled alpha-synuclein derivatives. We show that membrane interaction is mediated by major conformational changes within seven N-terminal 11-aa repeats, which reorganize from a highly dynamic structure into an elongated helical structure devoid of significant tertiary packing. Furthermore, we find that analogous positions from different repeats are in equivalent locations with respect to membrane proximity. These and other findings suggest a curved membrane-dependent alpha-helical structure, wherein each 11-aa repeat takes up three helical turns. Similar helical structures could also apply to apolipoproteins and other lipid-interacting proteins with related 11-aa repeats.

Topics: alpha-Synuclein; Amino Acid Sequence; Cell Membrane; Cysteine; Electron Spin Resonance Spectroscopy; Humans; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Structure, Secondary; Spin Labels; Synucleins

The 140-amino-acid protein alpha-synuclein (alpha-syn) is the major constituent of Lewy bodies. The protein interacts with several intracellular signal transduction pathways. Reasons for onset of abnormal aggregation of alpha-syn are unclear. Metal ions, oxidative stress, and beta-amyloid 1-42 (Abeta1-42) are important induction factors for alpha-syn aggregation. beta-Synuclein (beta-syn) can counteract alpha-syn aggregation. Cross-breeding of beta-syn transgenic mice with animals overexpressing alpha-syn significantly decreased alpha-syn-positive neuronal inclusion bodies and improved motor function. This was an important proof of concept for the role of beta-syn in regulating alpha-syn aggregation. A drug discovery program based on peptide derivatives (N-terminal amino acids 1-15) of beta-syn was initiated. For screening, tissue culture models simulating disease-specific conditions were utilized. They protected against growth factor withdrawal, Abeta toxicity, and oxidative stress. Three peptides were selected (KEGV, SMAKEGV, MDFMKGLSMAKE) for in vivo studies because they also decreased expression of Abeta1-40 and Abeta1-42. First, in vivo experiments were made in human amyloid precursor protein (APP [Swedish and London mutation]) transgenic mice, as well as alpha-syn transgenic mice. Treatment was performed with the peptides as an intraperitoneal injection or as intranasal droplets for 2 mo. Behavioral studies in APP transgenic mice were performed after 1 and 2 mo of treatment and showed clear effects of these peptides.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; beta-Synuclein; Cells, Cultured; Chick Embryo; Disease Models, Animal; Down-Regulation; Humans; Lewy Bodies; Mice; Mice, Transgenic; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuroprotective Agents; Oxidative Stress; Peptide Fragments; Synucleins

Geldanamycin (GA) is a naturally occurring benzoquinone ansamycin that induces heat shock protein 70 (Hsp70). GA has been shown to reduce alpha-synuclein induced neurotoxicity in a fly model of Parkinson's disease. We have previously shown that heat shock proteins can prevent alpha-synuclein aggregation and protect against alpha-synuclein induced toxicity in human H4 neuroglioma cells. Here, we hypothesize that GA treatment will reduce alpha-synuclein aggregation and prevent alpha-synuclein induced toxicity and we show that GA can induce Hsp70 in a time- and concentration-dependent manner in H4 cells. Pretreatment with 200nM GA 24h prior to transfection prevented alpha-synuclein aggregation and protected against toxicity. Treatment of cells with pre-existing inclusions with GA did not result in a reduction in the number of cells containing inclusions, suggesting that upregulation of Hsp70 is not sufficient to remove established inclusions. Similarly, Western blot analysis demonstrated that GA treatment could dramatically reduce both total alpha-synuclein and high molecular weight alpha-synuclein aggregates. Taken together, these data suggest that GA is effective in preventing alpha-synuclein aggregation and may represent a pharmacological intervention to therapeutically increase expression of molecular chaperone proteins to treat neurodegenerative diseases where aggregation is central to the pathogenesis.

Topics: alpha-Synuclein; Animals; Antibiotics, Antineoplastic; Benzoquinones; Cell Line, Tumor; Dose-Response Relationship, Drug; Enzyme Inhibitors; HSP70 Heat-Shock Proteins; Humans; Inclusion Bodies; Lactams, Macrocyclic; Nerve Tissue Proteins; Neurodegenerative Diseases; Quinones; Synucleins; Up-Regulation

The novel basic, heat-stable tubulin polymerization promoting protein TPPP/p25 is associated with microtubules in vitro and can induce the formation of aberrant microtubule assemblies. We show by 1H-NMR spectroscopy that TPPP/p25 is natively unfolded. Antisera against peptide 186GKGKAGRVDLVDESG200NH2 (186-200) are highly specific to TPPP/p25. Immunohistochemistry and confocal microscopy demonstrates that TPPP/p25 is enriched in filamentous alpha-synuclein bearing Lewy bodies of Parkinson's (PD) and diffuse Lewy body disease (DLBD), as well as glial inclusions of multiple system atrophy (MSA). There is a correlation between TPPP/p25 and alpha-synuclein immunoreactivity in Western blot. In contrast, TPPP/p25 is not associated with abnormally phosphorylated tau in various inclusions of Pick's disease (PiD), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). However, electron microscopy confirms clusters of TPPP/p25 immunoreactivity along filaments of unstructured but not compact neurofibrillary tangles in Alzheimer's disease (AD). TPPP/p25 seems to be a novel marker of alpha-synucleinopathies.

Topics: Aged; alpha-Synuclein; Animals; Biomarkers; Blotting, Western; Brain; Cattle; Female; Humans; Immune Sera; Immunohistochemistry; Magnetic Resonance Spectroscopy; Male; Microscopy, Electron; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Folding; Synucleins

Accumulation of alpha-synuclein in brain is a hallmark of synucleinopathies, neurodegenerative diseases that include Parkinson's disease. Mice overexpressing alpha-synuclein under the Thy-1 promoter (ASO) show abnormal accumulation of alpha-synuclein in cortical and subcortical regions of the brain, including the substantia nigra. We examined the motor deficits in ASO mice with a battery of sensorimotor tests that are sensitive to alterations in the nigrostriatal dopaminergic system. Male wild-type and ASO mice were tested every 2 months for 8 months for motor performance and coordination on a challenging beam, inverted grid, and pole, sensorimotor deficits in an adhesive removal test, spontaneous activity in a cylinder, and gait. Fine motor skills were assessed by the ability to grasp cotton from a bin. ASO mice displayed significant impairments in motor performance and coordination and a reduction in spontaneous activity as early as 2 months of age. Motor performance and coordination impairments became progressively worse with age and sensorimotor deficits appeared at 6 months. Fine motor skills were altered at 4 months and worsened at 8 months. These data indicate that overexpression of alpha-synuclein induced an early and progressive behavioral phenotype that can be detected in multiple tests of sensorimotor function. These behavioral deficits provide a useful way to assess novel drug therapy in genetic models of synucleinopathies.

Topics: alpha-Synuclein; Animals; Corpus Striatum; Gait; Humans; Male; Mice; Mice, Transgenic; Motor Skills; Nerve Tissue Proteins; Neurodegenerative Diseases; Polyneuropathies; Postural Balance; Psychomotor Disorders; Psychomotor Performance; Substantia Nigra; Synucleins

Increased attention has been given to alpha-synuclein aggregation in nonsynucleinopathies because alpha-synuclein-containing Lewy bodies (LBs) influence symptoms. However, the spectrum of disorders in which secondary inclusions are likely to occur has not been defined. Amygdala neurons commonly develop large numbers of secondary LBs, making it a practical region for studying this phenomenon.. To characterize the spectrum of diseases associated with LB formation in the amygdala of neurodegenerative disease and control cases.. An autopsy series of 101 neurodegenerative disease and 34 aged control cases. Using immunohistochemistry studies, we examined the amygdala for alpha-synuclein aggregates.. Lewy bodies were often abundant in classic Pick disease, argyrophilic grain disease, Alzheimer disease, and dementia with LBs but not in cases with amygdala degeneration lacking tau-based inclusions, control cases, preclinical disease carriers, or degenerative diseases lacking pathologic involvement of the amygdala. The exposed alpha-synuclein epitopes were similar in all cases containing LBs.. Abnormal alpha-synuclein aggregation in the amygdala is disease selective, but not restricted to disorders of alpha-synuclein and beta-amyloid. Our data are compatible with the notion that tau aggregates predispose neurons to develop secondary LBs.

Topics: alpha-Synuclein; Amygdala; Humans; Lewy Bodies; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins; tau Proteins; Tauopathies

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

alpha-Synuclein is a major component of Lewy bodies in the brains of patients with Parkinson's disease (PD) as well as of neuronal/glial inclusions in a subset of neurodegenerative disorders collectively termed synucleinopathies. Here we studied by immunohistochemistry the accumulation of alpha-synuclein in transgenic (TG) Drosophila overexpressing wild-type (WT) or familial PD-linked mutant (i.e. A30P and A53T) alpha-synuclein in neurons, with special reference to the phosphorylation at Ser129, that is characteristic of human synucleinopathy lesions. Progressive accumulation of human alpha-synuclein was widely observed in the cell bodies and neurites of major neuronal nuclei in TG Drosophila brains, and phosphorylation of alpha-synuclein at Ser129 was detected in a limited subset of neurons approximately 1 week after alpha-synuclein immunoreactivity was first detected. Phosphorylated alpha-synuclein was most abundant in A53T mutant, followed by A30P and WT Drosophila. These results suggest that accumulation and phosphorylation of alpha-synuclein is recapitulated in neurons of alpha-synuclein transgenic Drosophila, that underscores the relevance of this model to human synucleinopatheis.

Topics: alpha-Synuclein; Animals; Drosophila; Immunohistochemistry; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Phosphorylation; Serine; Synucleins; Time Factors

Neurodegenerative diseases share symptoms suggested to be related to the serotonergic system. To evaluate the involvement of serotonergic raphe nuclei, we compared the percentage of neurons synthesizing serotonin in the nucleus centralis superior (NCS), raphe obscurus and pallidus (NROP) in Alzheimer's disease (AD), progressive supranuclear palsy (PSP), Parkinson's disease (PD), multiple system atrophy (MSA), and control brains. We used immunohistochemistry for tryptophan hydroxylase (TpOH), phosphorylated tau, and alpha-synuclein. We observed a significant decrease in the NCS in the NROP in AD, but a significant increase in PSP and MSA. Cytoskeletal pathology was present in the NCS and NROP to a variable degree. We conclude that there is disease- and nucleus-specific alteration of serotonin synthesis in the raphe.

Topics: Aged; alpha-Synuclein; Alzheimer Disease; Female; Humans; Male; Medulla Oblongata; Middle Aged; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; Phosphorylation; Pons; Protein Processing, Post-Translational; Raphe Nuclei; Serotonin; Supranuclear Palsy, Progressive; Synucleins; tau Proteins; Tryptophan Hydroxylase

We used a high-titer recombinant adeno-associated virus (rAAV) vector to express WT or mutant human alpha-synuclein in the substantia nigra of adult marmosets. The alpha-synuclein protein was expressed in 90-95% of all nigral dopamine neurons and distributed by anterograde transport throughout their axonal and dendritic projections. The transduced neurons developed severe neuronal pathology, including alpha-synuclein-positive cytoplasmic inclusions and granular deposits; swollen, dystrophic, and fragmented neuritis; and shrunken and pyknotic, densely alpha-synuclein-positive perikarya. By 16 wk posttransduction, 30-60% of the tyrosine hydroxylase-positive neurons were lost, and the tyrosine hydroxylase-positive innervation of the caudate nucleus and putamen was reduced to a similar extent. The rAAV-alpha-synuclein-treated monkeys developed a type of motor impairment, i.e., head position bias, compatible with this magnitude of nigrostriatal damage. rAAV vector-mediated alpha-synuclein gene transfer provides a transgenic primate model of nigrostriatal alpha-synucleinopathy that is of particular interest because it develops slowly over time, like human Parkinson's disease (PD), and expresses neuropathological features (alpha-synuclein-positive inclusions and dystrophic neurites, in particular) that are similar to those seen in idiopathic PD. This model offers new opportunities for the study of pathogenetic mechanisms and exploration of new therapeutic targets of particular relevance to human PD.

Topics: alpha-Synuclein; Amphetamines; Animals; Callithrix; Dependovirus; Disease Models, Animal; Dopamine; Genetic Vectors; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Parkinson Disease; Substantia Nigra; Synucleins; Time Factors; Tyrosine 3-Monooxygenase

We carried out immunohistochemical examinations of the brains (cerebella) of patients who had suffered from Parkinson's disease (PD), diffuse Lewy body disease (DLBD) or multiple system atrophy (MSA), using antibodies specific for alpha-synuclein. Alpha-synuclein-positive doughnut-shaped structures were found occasionally in the cerebellar molecular layer in some of these patients. Double-labeling immunofluorescence and immunoelectron microscopy studies revealed that these alpha-synuclein-positive doughnut-shaped structures were located in the glial fibrillary acidic protein-positive radial processes of Bergmann glia, corresponding to the outer area of Lewy body-like inclusions, and consisted of granulo-filamentous structures. These findings indicate that, although not frequently, Bergmann glia of the cerebellum are also the targets of alpha-synuclein pathology in alpha-synucleinopathies such as PD, DLBD and MSA.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Cerebellum; Female; Humans; Immunohistochemistry; Lewy Body Disease; Male; Microglia; Microscopy, Immunoelectron; Middle Aged; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Synucleins

alpha-Synuclein-positive cytoplasmic inclusions are a pathological hallmark of several neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Here we report that Sept4, a member of the septin protein family, is consistently found in these inclusions, whereas five other septins (Sept2, Sept5, Sept6, Sept7, and Sept8) are not found in these inclusions. Sept4 and alpha-synuclein can also be co-immunoprecipitated from normal human brain lysates. When co-expressed in cultured cells, FLAG-tagged Sept4 and Myc-tagged alpha-synuclein formed detergent-insoluble complex, and upon treatment with a proteasome inhibitor, they formed Lewy body-like cytoplasmic inclusions. The tagged Sept4 and alpha-synuclein synergistically accelerated cell death induced by the proteasome inhibitor, and this effect was further enhanced by expression of another Lewy body-associated protein, synphilin-1, tagged with the V5 epitope. Moreover, co-expression of the three proteins (tagged Sept4, alpha-synuclein, and synphilin-1) was sufficient to induce cell death. These data raise the possibility that Sept4 is involved in the formation of cytoplasmic inclusions as well as induction of cell death in alpha-synuclein-associated neurodegenerative disorders.

Topics: Aged; alpha-Synuclein; Animals; Biomarkers, Tumor; Brain; Carrier Proteins; Cell Death; Cell Line; Cytoskeletal Proteins; Cytoskeleton; GTP Phosphohydrolases; GTP-Binding Proteins; Humans; Inclusion Bodies; Intracellular Signaling Peptides and Proteins; Lewy Bodies; Mice; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; Septins; Synucleins; Transfection

Alpha-synuclein (alpha-syn) and tau polymerize into amyloid fibrils and form intraneuronal filamentous inclusions characteristic of neurodegenerative diseases. We demonstrate that alpha-syn induces fibrillization of tau and that coincubation of tau and alpha-syn synergistically promotes fibrillization of both proteins. The in vivo relevance of these findings is grounded in the co-occurrence of alpha-syn and tau filamentous amyloid inclusions in humans, in single transgenic mice that express A53T human alpha-syn in neurons, and in oligodendrocytes of bigenic mice that express wild-type human alpha-syn plus P301L mutant tau. This suggests that interactions between alpha-syn and tau can promote their fibrillization and drive the formation of pathological inclusions in human neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid; Animals; Biopolymers; Brain Chemistry; Humans; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Electron; Microscopy, Fluorescence; Microscopy, Immunoelectron; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Oligodendroglia; Protein Conformation; Protein Isoforms; Synucleins; tau Proteins; Tauopathies

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

Familial idiopathic brain calcification (FIBC) is a rare disorder characterised by autosomal dominant transmission, adult onset cerebellar and/or extrapyramidal features and idiopathic calcification of the brain. We present a family with FIBC where pathological studies showed that the proband had alpha-synuclein-immunopositive glial and neuronal cytoplasmic inclusions in oligodendrocytes in the putamen, midbrain and pons. This may represent a new and familial alpha-synuclein disorder causing a predominantly extrapyramidal picture similar to multisystem atrophy.

Topics: Adolescent; Adult; alpha-Synuclein; Brain; Calcinosis; Child; Female; Humans; Immunohistochemistry; Inclusion Bodies; Male; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Neuroglia; Pedigree; Plaque, Amyloid; Synucleins; Tomography, X-Ray Computed

Overexpression of human alpha-synuclein in model systems, including cultured neurons, drosophila and mice, leads to biochemical and pathological changes that mimic synucleopathies including Parkinson's disease. We have overexpressed both wild-type (WT) and mutant alanine53-->threonine (A53T) human alpha-synuclein by transgenic injection into Caenorhabditis elegans. Motor deficits were observed when either WT or A53T alpha-synuclein was overexpressed with a pan-neuronal or motor neuron promoter. Neuronal and dendritic loss were accelerated in all three sets of C. elegans dopaminergic neurons when human alpha-synuclein was overexpressed under the control of a dopaminergic neuron or pan-neuronal promoter, but not with a motor neuron promoter. There were no significant differences in neuronal loss between overexpressed WT and A53T forms or between worms of different ages (4 days, 10 days or 2 weeks). These results demonstrate neuronal and behavioral perturbations elicited by human alpha-synuclein in C. elegans that are dependent upon expression in specific neuron subtypes. This transgenic model in C. elegans, an invertebrate organism with excellent experimental resources for further genetic manipulation, may help facilitate dissection of pathophysiologic mechanisms of various synucleopathies.

Topics: alpha-Synuclein; Animals; Animals, Genetically Modified; Behavior, Animal; Biological Assay; Caenorhabditis elegans; Cell Count; Disease Models, Animal; Dopamine; Genes, Reporter; Humans; Motor Activity; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Synucleins

alpha-Synuclein is a presynaptic protein that accumulates abnormally in Lewy bodies of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Its physiological function and role in neuronal death remain poorly understood. Recent immunohistochemical studies suggest that cell cycle-related phenomena may play a role in the pathogenesis of Alzheimer's disease and perhaps other neurodegenerative disorders. In this investigation, we examined the effects of alpha-synuclein expression levels on cell cycle indices in PC12 cells engineered to conditionally induce alpha-synuclein expression upon withdrawal of doxycycline. Over-expression of alpha-synuclein resulted in enhanced proliferation rate and enrichment of cells in the S phase of the cell cycle. This was associated with increased accumulation of the mitotic factor cyclin B and down-regulation of the tumor suppressor retinoblastoma 2. Additionally, ERK1/2, key molecules in proliferation signaling, were highly phosphorylated. Immunohistochemical studies on postmortem brains revealed intense cyclin B immunoreactivity in Lewy bodies in cases with DLB and to a lesser extent in PD. We propose that elevated expression of alpha-synuclein causes changes in cell cycle regulators through ERK activation leading to apoptosis of postmitotic neurons. These changes in cell cycle proteins are also associated with ectopic expression of cyclin B in Lewy bodies.

Topics: alpha-Synuclein; Animals; Anti-Bacterial Agents; Blotting, Western; Brain; Bromodeoxyuridine; Cell Count; Cell Cycle; Cell Division; Clone Cells; Culture Media, Serum-Free; Cyclin B; Cyclin D3; Cyclins; DNA; Dose-Response Relationship, Drug; Doxycycline; Flow Cytometry; Humans; Immunohistochemistry; Lewy Bodies; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Nerve Tissue Proteins; Neurodegenerative Diseases; Parkinson Disease; PC12 Cells; Rats; Synucleins; Time Factors; Transfection

Two mutations in alpha-synuclein, the main constituent of Lewy bodies, have been identified in familial Parkinson's disease. We have stereotactically injected lentiviral vectors encoding wild-type and A30P mutant human alpha-synuclein in different brain regions (striatum, substantia nigra, amygdala) of mice. Overexpression of alpha-synuclein induced time-dependent neuropathological changes reminiscent of Lewy pathology: abnormal accumulation of alpha-synuclein in cell bodies and neurites, alpha-synuclein-positive neuritic varicosities and cytoplasmic inclusions that stained with ubiquitin antibodies and became larger and more frequent with time. After one year, alpha-synuclein- and ubiquitin-positive neurons displayed a degenerative morphology and a significant loss of alpha-synuclein-positive cells was observed. Similar findings were observed with both the wild-type and the A30P mutant form of alpha-synuclein and this in different brain regions. This indicates that overexpression of alpha-synuclein is sufficient to induce Lewy-like pathology and neurodegeneration and that this effect is not restricted to dopaminergic cells. Our data also demonstrate the use of lentiviral vectors to create animal models for neurodegenerative diseases.

Topics: alpha-Synuclein; Amygdala; Animals; Blotting, Western; Cell Count; Corpus Striatum; Disease Models, Animal; Female; Humans; Immunohistochemistry; Inclusion Bodies, Viral; Lentivirus Infections; Lewy Body Disease; Mice; Mice, Inbred C57BL; Microscopy, Confocal; Mutation; Nerve Tissue Proteins; Neurites; Neuroblastoma; Neurodegenerative Diseases; Neurons; Substantia Nigra; Synucleins; Time Factors; Transduction, Genetic; Tumor Cells, Cultured; Tyrosine 3-Monooxygenase; Ubiquitin

Proteinaceous inclusions with amyloidogenic properties are a common link between many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Histological and in vitro studies of amyloid fibrils have advanced the understanding of protein aggregation, and provided important insights into pathogenic mechanisms of these neurodegenerative brain amyloidoses. The classical amyloid dyes Congo Red (CR) and thioflavin T and S, have been used extensively to detect amyloid inclusions in situ. These dyes have also been utilized to monitor the maturation of amyloid fibrils assembled from monomer subunits in vitro. Recently, the compound (trans,trans)-1-bromo-2,5-bis-(3- hydroxycarbonyl-4-hydroxy)styrylbenzene (BSB), derived from the structure of CR, was shown to bind to a wide range of amyloid inclusions in situ. More importantly it was also used to label brain amyloids in live animals. Herein, we show that an analogue of BSB, (trans,trans)-1-bromo-2,5-bis-(4-hydroxy)styrylbenzene (K114), recognizes amyloid lesions, and has distinctive properties which allowed the quantitative monitoring of the formation of amyloid fibrils assembled from the amyloid-beta peptide, alpha-synuclein, and tau.

Topics: alpha-Synuclein; Amyloid; Congo Red; Fluorescent Dyes; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Sensitivity and Specificity; Spectrometry, Fluorescence; Staining and Labeling; Styrenes; Synucleins; tau Proteins

Olfactory dysfunction increases with disease severity in Alzheimer's disease (AD), is early and independent of disease severity in Parkinson's disease (PD), but is absent in progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Previous histopathologic studies of olfactory bulbs in AD have shown neurofibrillary tangles (NFTs) and senile plaques while Lewy bodies (LBs) have been described in PD. Little is known about olfactory bulb pathology in PSP and CBD. Tau and alpha-synuclein pathology was assessed with immunohistochemistry in olfactory bulbs of AD (N=15), Lewy body disease (LBD; N=10), LBD with concurrent AD (AD/LBD; N=19), PSP (N=27), CBD (N=3) and cases with no significant neurodegenerative pathology (NSP; N=15). The Braak NFT stage, counts of senile plaques and NFT in cortical and hippocampal sections, and counts of LBs in amygdala and cortical sections were recorded for each case. Apolipoprotein E (APOE) genotypes were determined on DNA prepared from frozen brain tissue. All AD and AD/LBD cases and nine of 10 LBD cases had tau pathology in the anterior olfactory nucleus (AON), but it was uncommon in PSP (9/27), CBD (0/3) and NSP (5/15). Multiple linear regression analysis demonstrated that tau pathology in the AON correlated with Braak stage (P<0.001), cortical LB counts (P<0.001), as well as APOE epsilon4. Tau pathology is common in the olfactory bulb of AD and LBD but is minimal or absent in PSP and CBD. It correlates with APOE epsilon4, severity of tau pathology in the brain and surprisingly with cortical and amygdala LBs, suggesting a possible synergistic effect between tau and synuclein in the AON in cases with both pathologic processes.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Apolipoprotein E4; Apolipoproteins E; Female; Gene Frequency; Humans; Immunohistochemistry; Lewy Body Disease; Linear Models; Male; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Olfactory Bulb; Supranuclear Palsy, Progressive; Synucleins; tau Proteins

Alpha-synuclein (alphaS) is an abundant neuronal protein that accumulates in insoluble inclusions in Parkinson's disease (PD) and the related disorder, dementia with Lewy bodies (DLB). A central question about the role of alphaS in the pathogenesis of PD and DLB concerns how this normally soluble protein assembles into insoluble aggregates associated with neuronal dysfunction. We recently detected highly soluble oligomers of alphaS in normal brain supernatants and observed their augmentation in PD and DLB brains. Further, we found that polyunsaturated fatty acids (PUFAs) enhanced alphaS oligomerization in intact mesencephalic neuronal cells. We now report the presence of elevated PUFA levels in PD and DLB brain soluble fractions. Higher PUFA levels were also detected in the supernatants and high-speed membrane fractions of neuronal cells over-expressing wild-type or PD-causing mutant alphaS. This increased PUFA content in the membrane fraction was accompanied by increased membrane fluidity in the alphaS overexpressing neurons. In accord, membrane fluidity and the levels of certain PUFAs were decreased in the brains of mice genetically deleted of alphaS. Together with our earlier observations, these results suggest that alphaS-PUFA interactions help regulate neuronal PUFA levels as well as the oligomerization state of alphaS, both normally and in human synucleinopathies.

Topics: alpha-Synuclein; Animals; Brain; Brain Chemistry; Cell Membrane; Cytosol; Dopamine; Fatty Acids; Fatty Acids, Unsaturated; Gas Chromatography-Mass Spectrometry; Humans; Lewy Bodies; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Chemical; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Protein Binding; Synucleins; Time Factors; Transfection

Alpha-synuclein and its missense mutants (A30P, A53T) have been linked to the genesis of idiopathic and rare familial forms of Parkinson's disease, respectively. Here we show that, similar to the wild-type alpha-synuclein, the A30P mutant forms a strong complex with the human dopamine transporter (hDAT), through direct protein:protein interactions between the nonamyloid beta component (NAC) domain of the A30P mutant and the last 22 aminoacyl residues of the carboxy-terminal tail of hDAT. The A30P mutant negatively modulates hDAT functional activity and to a greater extent than wild-type alpha-synuclein, with reduced uptake of extracellular dopamine and dopamine-mediated, hDAT-dependent cytotoxicity. By contrast, the A53T mutant neither forms a strong protein:protein complex with hDAT nor modulates dopamine uptake by hDAT, and dopamine-mediated, hDAT-dependent cytotoxicity is higher than with either wild-type or the A30P variant of alpha-synuclein, but not significantly different from that of cells expressing hDAT alone. Confocal microscopy shows substantial overlap in colocalization of all three alpha-synuclein variants with hDAT, with only minor differences. Although the complex formation with hDAT occurs through the NAC domain of the alpha-synuclein variants, it is the familial Parkinson's disease-linked missense mutations present in the amino-terminal lipid binding domain of the alpha-synuclein variants that dictate the extent of the regulation of hDAT function. These studies highlight previously unknown properties of the A30P and the A53T mutants of alpha-synuclein with respect to the modulation of hDAT activity and/or regulation, and its subsequent functional outcome, which are uniquely distinct.

Topics: alpha-Synuclein; Animals; Cell Death; Cell Line; Dopamine; Dopamine Plasma Membrane Transport Proteins; Humans; Lipid Metabolism; Membrane Glycoproteins; Membrane Transport Proteins; Mice; Mutation, Missense; Nerve Tissue Proteins; Neurodegenerative Diseases; Oxidative Stress; Protein Binding; Protein Structure, Tertiary; Synucleins

Alpha-synuclein was implicated in Parkinson's disease when missense mutations in the alpha-synuclein gene were found in autosomal dominant Parkinson's disease and alpha-synuclein was shown to be a major constituent of protein aggregates in sporadic Parkinson's disease and other synucleinopathies. We have generated transgenic mice expressing A53T mutant and wild-type human alpha-synuclein. The mutant transgenic protein was distributed abnormally to the axons, perikarya, and dendrites of neurons in many brain areas. In electron microscopic immunogold studies, no aggregation of alpha-synuclein was found in these mice. However, behavior analysis showed a progressive reduction of spontaneous vertical motor activity in both mutant lines correlating with the dosage of overexpression. In addition, deficits of grip strength, rotarod performance, and gait were observed in homozygous PrPmtB mice. Transgenic animals expressing mutant alpha-synuclein may be a valuable model to assess specific aspects of the pathogenesis of synucleinopathies.

Topics: alpha-Synuclein; Animals; Cattle; Cell Aggregation; Female; Gene Expression Regulation; Humans; Male; Mice; Mice, Transgenic; Mutation; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Synucleins

To examine the effects of aggregation-inducing motifs related to neurodegenerative diseases on amyloid formation of host protein, we prepared several chimera myoglobins, in which various aggregation-inducing motifs were inserted. The focused aggregation-inducing motifs included five (R5) or two (R2) oligopeptide repeats in yeast Sup35p, five octapeptide repeats (OPR) in the human prion protein, a nonamyloid beta component (NAC) in alpha-synuclein, and tandem repeats of 50 glutamines (Q50). Circular dichroism and infrared spectroscopies suggested that the OPR, R5, and Q50 motifs formed an antiparallel beta sheet as well as a random coil, whereas the R2 and NAC motifs mainly formed random coils. The OPR, R5, and Q50 mutants, but not the R2 and NAC mutants, readily formed the SDS-resistant aggregates under physiological condition, and electron microscopy revealed that the aggregates contained amyloid fibrils. The destabilization and increase in gyration radius of the OPR, R5, and Q50 mutants correlated with the tendency to form amyloid fibrils. A control mutant bearing a nonamyloidgenic sequence was also moderately destabilized but did not form amyloid fibrils. Therefore, we concluded that the OPR, R5, and Q50 motifs, even in a quite stable protein such as myoglobin, led the host protein to formation of amyloid fibrils under physiological condition.

Topics: alpha-Synuclein; Amino Acid Motifs; Amino Acid Sequence; Amyloid; Animals; Circular Dichroism; Fungal Proteins; Humans; Molecular Sequence Data; Mutagenesis, Insertional; Myoglobin; Nerve Tissue Proteins; Neurodegenerative Diseases; Nuclear Magnetic Resonance, Biomolecular; Oligopeptides; Peptide Termination Factors; Prions; Protein Denaturation; Protein Engineering; Protein Structure, Secondary; Recombinant Fusion Proteins; Repetitive Sequences, Amino Acid; Saccharomyces cerevisiae Proteins; Spectroscopy, Fourier Transform Infrared; Synucleins; Whales

We evaluate cellular prion protein (PrP(C)) immunoreactivity (IR) in Alzheimer's, Parkinson's, diffuse Lewy body, and motor neuron diseases (MND), progressive supranuclear palsy, and multiple system atrophy. We use immunohistochemistry for PrP, including five monoclonal antibodies against different epitopes and three different pretreatments, alpha-synuclein, phosphorylated tau, beta-amyloid, and ubiquitin. Disease-specific inclusions are devoid of PrP(C) IR. Using double immunofluorescence and confocal laser microscopy we observe focal overlapping of PrP(C) with tau and with alpha-synuclein in early, but not in fully developed inclusions. However, PrP(C) IR neurons may contain abnormal tau or alpha-synuclein aggregates. Additionally, we observe a loss of PrP(C) IR in anterior horn neurons in MND. Our results suggest that expression of PrP(C) reflects a general response to cellular stress rather than specific co-operation in aggregation of other proteins.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Brain Chemistry; Fluorescent Antibody Technique; Humans; Lewy Bodies; Microscopy, Confocal; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrillary Tangles; Prions; Synucleins; tau Proteins

alpha-Synuclein has been implicated in the pathogenesis of Parkinson disease (PD) and related neurodegenerative disorders. More recently, it has been suggested to be an important regulatory component of vesicle transport in neuronal cells. alpha-Synuclein is also highly expressed in platelets and is loosely associated with the membrane of the secretory alpha-granules. However, the functional significance of these observations is unknown. In this study, the possible function of alpha-synuclein in vesicle transport, with particular regard to alpha-granule release from the platelets, was investigated. The results showed that ionomycin- or thrombin-induced alpha-granule secretion was inhibited by exogenous alpha-synuclein addition in a dose-dependent manner. However, [(3)H]5-HT release from the dense granules and hexosaminidase release from the lysosomal granules were not affected. Two point mutants (A30P and A53T) found in some familial types of PD, in addition to beta-synuclein and alpha-synuclein112, effectively inhibited PF4 release from the alpha-granules. However, the deletion mutants, which completely lacked either the N-terminal region or the C-terminal tail, did not affect alpha-granule release. Interestingly, exogenously added alpha-synuclein appeared to enter the platelets but did not change the Ca(++) level in the platelets at the resting state and the increase in the Ca(++) level on stimulation. Electron microscopy also supported that alpha-synuclein inhibits alpha-granule release. These results suggest that alpha-synuclein may function as a specific negative regulator of alpha-granule release in platelets.

Topics: alpha-Synuclein; beta-Synuclein; Blood Platelets; Calcium; Cytoplasmic Granules; Humans; Ionomycin; Kinetics; Microscopy, Electron; Nerve Tissue Proteins; Neurodegenerative Diseases; Point Mutation; Recombinant Proteins; Synucleins; Thrombin

alpha-Synuclein is one of the major components of intracellular fibrillary aggregates in the brains of a subset of neurodegenerative disorders, including Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, and Hallervorden-Spatz disease, which are referred to as alpha-synucleinopathies. We have shown previously (Fujiwara, H., Hasegawa, M., Dohmae, N., Kawashima, A., Masliah, E., Goldberg, M. S., Shen, J., Takio, K., and Iwatsubo, T. (2002) Nat. Cell Biol. 4, 160-164) that alpha-synuclein deposited in synucleinopathy brains is extensively phosphorylated at Ser-129 and migrates at 15 kDa. Here we examined the biochemical characteristics of the additional, higher molecular mass species of phosphorylated alpha-synuclein-positive polypeptides that also are recovered in the Sarkosyl-insoluble fraction of synucleinopathy and migrate at about 22 and 29 kDa. These 22 and 29 kDa bands were positive for three different anti-ubiquitin antibodies and comigrated perfectly with in vitro ubiquitinated alpha-synuclein that may correspond to mono- and diubiquitinated alpha-synuclein, respectively. Furthermore, cyanogen bromide cleavage of the 22 and 29 kDa polypeptides shifted the mobility to 19 and 26 kDa, respectively, and they retained immunoreactivity for both ubiquitin and alpha-synuclein. Finally, protein sequence analysis showed that the 19 kDa band contained two amino-terminal sequences of alpha-synuclein and ubiquitin. These results strongly suggest that phosphorylated alpha-synuclein is targeted to mono- and diubiquitination in synucleinopathy brains, which may have implications for mechanisms of these diseases.

Topics: Aged; alpha-Synuclein; Amino Acid Sequence; Brain; Cyanogen Bromide; Female; Humans; Male; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Phosphorylation; Synucleins; Ubiquitin

We had previously reported that systemic overexpression of the alpha(1B)-adrenergic receptor (AR) in a transgenic mouse induced a neurodegenerative disease that resembled the parkinsonian-like syndrome called multiple system atrophy (MSA). We now report that our mouse model has cytoplasmic inclusion bodies that colocalize with oligodendrocytes and neurons, are positive for alpha-synuclein and ubiquitin, and therefore may be classified as a synucleinopathy. Alpha-synuclein monomers as well as multimers were present in brain extracts from both normal and transgenic mice. However, similar to human MSA and other synucleinopathies, transgenic mice showed an increase in abnormal aggregated forms of alpha-synuclein, which also increased its nitrated content with age. However, the same extracts displayed decreased phosphorylation of alpha-synuclein. Other traits particular to MSA such as Purkinje cell loss in the cerebellum and degeneration of the intermediolateral cell columns of the spinal cord also exist in our mouse model but differences still exist between them. Interestingly, long-term therapy with the alpha(1)-AR antagonist, terazosin, resulted in protection against the symptomatic as well as the neurodegeneration and alpha-synuclein inclusion body formation, suggesting that signaling of the alpha(1B)-AR is the cause of the pathology. We conclude that overexpression of the alpha(1B)-AR can cause a synucleinopathy similar to other parkinsonian syndromes.

Topics: Adrenergic alpha-Antagonists; alpha-Synuclein; Animals; Body Weight; Brain; Cerebellum; Disease Models, Animal; Female; Inclusion Bodies; Macromolecular Substances; Male; Mice; Mice, Transgenic; Motor Activity; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Nitrates; Oligodendroglia; Phosphorylation; Prazosin; Receptors, Adrenergic, alpha-1; Spinal Cord; Survival Rate; Synucleins; Tyrosine; Ubiquitin

The pathological modifications of alpha-synuclein (alphaS) in Parkinson disease and related diseases are poorly understood. We have detected misfolded alphaS in situ based on the proteinase K resistance (PK resistance) of alphaS fibrils, and using specific antibodies against S129-phosphorylated alphaS as well as oxidized alphaS. Unexpectedly massive neuritic pathology was found in affected human brain regions, in addition to classical alphaS pathology. PK resistance and abnormal phosphorylation of alphaS developed with increasing age in (Thy1)-h[A30P] alphaS transgenic mice, concomitant with formation of argyrophilic, thioflavin S-positive, and electron-dense inclusions that were occasionally ubiquitinated. alphaS pathology in the transgenic mice was predominantly in the brainstem and spinal cord. Astrogliosis was found in these heavily affected tissues. Homozygous mice showed the same pathology approximately one year earlier. The transgenic mice showed a progressive deterioration of locomotor function. Thus, misfolding and hyperphosphorylation of alphaS may cause dysfunction of affected brain regions.

Topics: alpha-Synuclein; Animals; Brain; Drug Resistance; Endopeptidase K; Female; Gene Dosage; Humans; In Vitro Techniques; Lewy Body Disease; Locomotion; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Tissue Proteins; Neurodegenerative Diseases; Phosphorylation; Protein Folding; Synucleins

Increasing evidence suggests that alpha-synuclein is a common pathogenic molecule in several neurodegenerative diseases, particularly in Parkinson's disease. To understand alpha-synuclein pathology, we investigated molecules that interact with alpha-synuclein in human and rat brains and identified tubulin as an alpha-synuclein binding/associated protein. Tubulin co-localized with alpha-synuclein in Lewy bodies and other alpha-synuclein-positive pathological structures. Tubulin initiated and promoted alpha-synuclein fibril formation under physiological conditions in vitro. These findings suggest that an interaction between tubulin and alpha-synuclein might accelerate alpha-synuclein aggregation in diseased brains, leading to the formation of Lewy bodies.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Brain; Humans; Microscopy, Electron; Microtubules; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Rats; Synucleins; Tubulin

The deposition of the abundant presynaptic brain protein alpha-synuclein as fibrillary aggregates in neurons or glial cells is a hallmark lesion in a subset of neurodegenerative disorders. These disorders include Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy, collectively referred to as synucleinopathies. Importantly, the identification of missense mutations in the alpha-synuclein gene in some pedigrees of familial PD has strongly implicated alpha-synuclein in the pathogenesis of PD and other synucleinopathies. However, specific post-translational modifications that underlie the aggregation of alpha-synuclein in affected brains have not, as yet, been identified. Here, we show by mass spectrometry analysis and studies with an antibody that specifically recognizes phospho-Ser 129 of alpha-synuclein, that this residue is selectively and extensively phosphorylated in synucleinopathy lesions. Furthermore, phosphorylation of alpha-synuclein at Ser 129 promoted fibril formation in vitro. These results highlight the importance of phosphorylation of filamentous proteins in the pathogenesis of neurodegenerative disorders.

Topics: Aged; alpha-Synuclein; Amino Acid Sequence; Brain Chemistry; Cerebral Cortex; Humans; Lewy Bodies; Mass Spectrometry; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Phosphoproteins; Recombinant Proteins; Serine; 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

Intracellular filamentous aggregates comprised of alpha-synuclein such as Lewy bodies and glial cytoplasmic inclusions are the defining hallmarks of a subset of neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. We have analyzed biochemical and structural properties of alpha-synuclein filaments assembled in vitro or extracted from brains of patients with multiple system atrophy and found that both types of filaments are insoluble to detergents and partially resistant to proteinase K digestion. Immunoelectron microscopy and immunoblot analysis showed that both amino and carboxyl termini of alpha-synuclein in in vitro assembled filaments were degraded by proteinase K treatment, whereas the central portion of alpha-synuclein is resistant to proteinase K and retains filamentous structures. Protein sequencing and mass spectrometric analyses of the proteinase K-resistant, minimal fragment of 7 kDa revealed that amino acid residues 31-109 of alpha-synuclein constitute the core unit of the filaments. These observations suggest that the central half of the alpha-synuclein polypeptide, containing five tandem repeats as well as a part of the carboxyl-terminal acidic region, forms the core structure of alpha-synuclein filaments, which is coated by the amino- and carboxyl-terminal portions at the periphery.

Topics: alpha-Synuclein; Amino Acid Sequence; Endopeptidase K; Humans; Microscopy, Immunoelectron; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Conformation; Recombinant Proteins; Sequence Homology, Amino Acid; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Synucleins

Alpha-synuclein is a major component of Lewy bodies (LB) in Parkinson's disease (PD) and dementia with LB (DLB), as well as of glial cytoplasmic inclusions (GCI) in multiple system atrophy (MSA). Recently, a novel protein called synphilin-1 has been identified that associates with alpha-synuclein, and it has been reported that co-transfection of both alpha-synuclein and synphilin-1 in mammalian cells yielded eosinophilic cytoplasmic inclusions resembling LB. Immunocytochemical and ultrastructural investigations have now been performed on the brain of patients with various neurodegenerative disorders using anti-synphilin-1 antibodies. These antibodies immunostained the neuropil in a punctate pattern throughout the brain of control subjects. In PD, most LB observed in the brain stem were positive for synphilin-1. These LB showed intense staining in their central cores, but their peripheral portions were only weakly stained or unstained. Pale bodies and Lewy neurites, which were positive for alpha-synuclein, were synphilin-1 negative. In DLB, a small fraction of cortical LB were immunolabeled by anti-synphilin-1. In MSA, numerous GCI were positive for synphilin-1. Immunoelectron microscopy revealed that the reaction product was localized within filamentous and circular structures in LB. Various neuronal and glial inclusions in neurodegenerative disorders other than LB disease and MSA were synphilin-1 negative. These findings suggest that abnormal accumulation of synphilin-1 is specific for brain lesions in which alpha-synuclein is a major component.

Topics: alpha-Synuclein; Brain; Carrier Proteins; Fluorescent Antibody Technique; Humans; Lewy Bodies; Microscopy, Immunoelectron; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins

Abnormal alpha-synuclein-positive glial cytoplasmic inclusions are found in Parkinson's disease, multiple system atrophy and dementia with Lewy bodies. We have recently developed an in vitro model of alpha-synuclein-immunoreactive aggregations in U373 astrocytoma cells. We have additionally overexpressed wild-type and a C-terminally truncated form of alpha-synuclein in primary rat glial cells. Astrocytes and oligodendrocytes were found to form alpha-synuclein-positive aggregations in vitro perinuclearly or in the processes of the cells. The morphological studies presented here demonstrate that the aggregations we have observed in vitro are not limited by a membrane but have unclear borders. They have an amorphous dense core that is intensely alpha-synuclein-immunopositive and a predominantly filamentous halo around. Mainly filamentous structures at the border area between the halo and the core are alpha-synuclein-immunoreactive. We conclude that this in vitro model of alpha-synuclein-positive glial aggregations mimics the morphology of the abnormal glial inclusions described in neurodegenerative disorders and could be a suitable model for studying their role in the pathogenesis of these diseases.

Topics: alpha-Synuclein; Animals; Astrocytoma; Cell Culture Techniques; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuroglia; Rats; Synucleins; Tumor Cells, Cultured

Recombinant adeno-associated viral vectors display efficient tropism for transduction of the dopamine neurons of the substantia nigra. Taking advantage of this unique property of recombinant adeno-associated viral vectors, we expressed wild-type and A53T mutated human alpha-synuclein in the nigrostriatal dopamine neurons of adult rats for up to 6 months. Cellular and axonal pathology, including alpha-synuclein-positive cytoplasmic inclusions and swollen, dystrophic neurites similar to those seen in brains from patients with Parkinson's disease, developed progressively over time. These pathological alterations occurred preferentially in the nigral dopamine neurons and were not observed in other nondopaminergic neurons transduced by the same vectors. The degenerative changes were accompanied by a loss of 30-80% of the nigral dopamine neurons, a 40-50% reduction of striatal dopamine, and tyrosine hydroxylase levels that was fully developed by 8 weeks. Significant motor impairment developed in those animals in which dopamine neuron cell loss exceeded a critical threshold of 50-60%. At 6 months, signs of cell body and axonal pathology had subsided, suggesting that the surviving neurons had recovered from the initial insult, despite the fact that alpha-synuclein expression was maintained at a high level. These results show that nigral dopamine neurons are selectively vulnerable to high levels of either wild-type or mutant alpha-synuclein, pointing to a key role for alpha-synuclein in the pathogenesis of Parkinson's disease. Targeted overexpression of alpha-synuclein in the nigrostriatal system may provide a new animal model of Parkinson's disease that reproduces some of the cardinal pathological, neurochemical, and behavioral features of the human disease.

Topics: 3,4-Dihydroxyphenylacetic Acid; alpha-Synuclein; Animals; Behavior, Animal; Cell Count; Cell Death; Corpus Striatum; Dependovirus; Disease Models, Animal; Disease Progression; Dopamine; Gene Targeting; Genetic Vectors; Humans; Motor Activity; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Organ Specificity; Parkinson Disease; Rats; Rats, Sprague-Dawley; Substantia Nigra; Synucleins; Tissue Distribution; Transduction, Genetic; Tyrosine 3-Monooxygenase

alpha-Synucleinopathies are neurodegenerative disorders that range pathologically from the demise of select groups of nuclei to pervasive degeneration throughout the neuraxis. Although mounting evidence suggests that alpha-synuclein lesions lead to neurodegeneration, this remains controversial. To explore this issue, we generated transgenic mice expressing wild-type and A53T human alpha-synuclein in CNS neurons. Mice expressing mutant, but not wild-type, alpha-synuclein developed a severe and complex motor impairment leading to paralysis and death. These animals developed age-dependent intracytoplasmic neuronal alpha-synuclein inclusions paralleling disease onset, and the alpha-synuclein inclusions recapitulated features of human counterparts. Moreover, immunoelectron microscopy revealed that the alpha-synuclein inclusions contained 10-16 nm wide fibrils similar to human pathological inclusions. These mice demonstrate that A53T alpha-synuclein leads to the formation of toxic filamentous alpha-synuclein neuronal inclusions that cause neurodegeneration.

Topics: alpha-Synuclein; Animals; Axons; Behavior, Animal; Brain; Disease Models, Animal; Female; Gene Expression Regulation; Humans; Inclusion Bodies; Male; Mice; Mice, Transgenic; Microscopy, Electron; Movement Disorders; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Phenotype; Recombinant Fusion Proteins; Solubility; Spinal Cord; Synucleins; Wallerian Degeneration

alpha-Synuclein has been implicated in various neurodegenerative disorders, including Parkinson's and Alzheimer's diseases, by its participation in abnormal protein depositions. As the protein has been suggested to play a significant role in the formation of the deposits which might be responsible for neurodegeneration, there is a strong demand to screen for alpha-synuclein-interactive small molecules. In this report, Coomassie Brilliant Blue (CBB) interaction of alpha-synuclein has been investigated with respect to induction of protein self-oligomerization in the presence of the chemical coupling reagent N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline. Both CBB-G and CBB-R, which differ by only two methyl groups, induced the self-oligomerization of alpha-synuclein in a biphasic manner with optimal dye concentrations of 250 microM and 150 microM, respectively. The protein aggregates of alpha-synuclein induced by the dyes in the absence of the coupling reagent were analysed by electron microscopy. Whereas CBB-G induced formation of protein aggregates with a worm-like structure, CBB-R induced clear fibrilization of alpha-synuclein on a background of granular structures. CBB-R interacted with alpha-synuclein approximately twice as effectively as CBB-G (dissociation constants 0.63 microM and 1.37 microM, respectively). These dye interactions were independent from the acidic C-terminus of alpha-synuclein, which was reminiscent of the Alphabeta25-35 interaction of alpha-synuclein. However, the metal-catalysed oxidative self-oligomerization of alpha-synuclein in the presence of Cu2+/H2O2, which was augmented synergistically by Alphabeta25-35, was not affected by the dyes. This indicates that the dye binding site is also distinctive from the Alphabeta25-35 interaction site on alpha-synuclein. These biochemically specific interactions between alpha-synuclein and the dyes indicate that alpha-synuclein-interactive small molecules could provide a tool with which to approach development of diagnostic, preventive, or therapeutic strategies for various alpha-synuclein-related neurodegenerative disorders.

Topics: alpha-Synuclein; Binding Sites; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Protein Conformation; Quinolines; Rosaniline Dyes; Synucleins

Although alpha-synuclein is expressed primarily in neurons, it is a major component of oligodendroglial and astrocytic inclusions in several neurodegenerative diseases. Recent study has further demonstrated that alpha-synuclein is expressed in cultured rat oligodendrocytes. We determined whether alpha-synuclein might be expressed in astrocytic cells. alpha-Synuclein mRNA and protein were detected in U251 human astrocytic glioma cells and normal human astrocytes, and the levels were increased in the former, but not in the latter, by stimulation with interleukin-1beta in a time- and concentration-dependent manner. Serum deprivation also led to an increase of alpha-synuclein mRNA and protein in U251 cells. Immunofluorescent staining confirmed the cell-associated alpha-synuclein. These findings suggest that human astrocytes can produce alpha-synuclein in culture and that certain inflammatory cytokines and cell stress increase alpha-synuclein expression.

Topics: alpha-Synuclein; Astrocytes; Astrocytoma; Culture Media, Serum-Free; Fluorescent Antibody Technique; Humans; Interleukin-1; Nerve Tissue Proteins; Neurodegenerative Diseases; RNA, Messenger; Synucleins; Tumor Cells, Cultured; Up-Regulation

We examined the immunoreactivity of ubiquitin-binding protein p62 and its association with ubiquitin (Ub), alpha-synuclein, and paired helical filament (PHF)-tau in the affected brain areas of human tauopathies and synucleinopathies. Ubiquitin-binding protein p62 is a widely expressed protein that can bind to Ub noncovalently and is involved in several signalling pathways, making p62 a candidate regulator of Ub-mediated proteolysis. We show that p62 immunoreactivity co-localizes with neuronal and glial Ub-containing inclusions in Alzheimer's disease, Pick's disease, dementia with Lewy bodies, Parkinson's disease, and multiple system atrophy. This is the first demonstration of a common protein component, apart from Ub, that is present in both PHF-tau and alpha-synuclein inclusions. In both tauo- and synucleinopathies, the staining patterns for p62 and Ub were markedly similar, suggesting that a common mechanism which requires interaction of p62 and Ub contributes to the formation of PHF-tau and alpha-synuclein inclusions.

Topics: Adaptor Proteins, Signal Transducing; Aged; Aged, 80 and over; alpha-Synuclein; Brain; Carrier Proteins; Female; Humans; Immediate-Early Proteins; Male; Middle Aged; Nerve Tissue Proteins; Neurites; Neurodegenerative Diseases; Proteins; Sequestosome-1 Protein; Synucleins; tau Proteins; Ubiquitins

Various protein aggregates of alpha-synuclein developed by way of the common protein self-oligomerization in the presence of Abeta25-35, copper, and eosin were examined. All the aggregates exhibited congo red birefringence although the actual amounts of the aggregates were varied as determined by thioflavin T binding fluorescence. When their morphologies were analyzed in relation to in vitro cytotoxicity, the smallest granular aggregates obtained with copper exhibited the highest cytotoxicity, while the fibrous structures by eosin did not affect the cell.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Benzothiazoles; Cells, Cultured; Copper; Eosine Yellowish-(YS); Fluorescent Dyes; Ligands; Microscopy, Electron; Nerve Tissue Proteins; Neurodegenerative Diseases; Peptide Fragments; Polymers; Protein Structure, Tertiary; Synucleins; Thiazoles

The synuclein family of proteins is a group of primarily brain-expressed polypeptides that show a high degree of amino acid conservation. alpha-Synuclein is the best known of the synuclein family, as it is a major component of the Lewy body, a cytoplasmic inclusion characteristic of Parkinson's disease as well as a variety of related neurodegenerative disorders. With the discovery that mutations in alpha-synuclein can cause Parkinson's disease, a potential role for the other synuclein family members in neurodegenerative disease is being considered. beta-Synuclein in particular may deserve special attention, as it is co-expressed with alpha-synuclein at presynaptic nerve terminals, is subject to phosphorylation by Ca(2+) calmodulin protein kinase II, appears important for neural plasticity, and forms aggregates in the brains of patients with Parkinson's disease and a related disorder. To facilitate study of beta-synuclein, we have cloned the mouse beta-synuclein gene (Sncb) and determined its genomic organization, size, and intron-exon structure. Using an interspecific backcross mapping panel from The Jackson Laboratory, we were then able to localize Sncb to chromosome 13 at the MGD 35.0 cM position. Like the human beta-synuclein gene, Sncb appears to consist of six exons separated by five introns. Unlike the human beta-synuclein gene, the mouse ortholog possesses a variant GC 5' splice donor sequence at the exon 4 - intron 4 boundary in a highly conserved splice junction consensus. Northern blot analysis and Western blot analysis both indicate that Sncb is highly expressed in the brain. Knowledge of the genomic organization and expression pattern of Sncb will allow functional studies of its potential role in neurodegeneration to commence in the mouse.

Topics: alpha-Synuclein; Amino Acid Sequence; Animals; Base Sequence; beta-Synuclein; Blotting, Western; Central Nervous System; Crosses, Genetic; Exons; Female; Gene Expression Profiling; Introns; Male; Mice; Molecular Sequence Data; Nerve Tissue Proteins; Neurodegenerative Diseases; Organ Specificity; Physical Chromosome Mapping; Restriction Mapping; RNA, Messenger; Sequence Alignment; Synucleins

Although its function is unknown, alpha-synuclein is widely distributed in neural tissue and is the major component in the pathological aggregates found in patients with Parkinson's disease, Alzheimer's disease, Down's syndrome, and multiple system atrophy. In this report, we have quantified the binding alpha-synucleins to lipid membranes. In contrast to previous studies, we find, using real time equilibrium fluorescence methods, that alpha-synuclein binds strongly to large, unilamellar vesicles with either anionic or zwitterionic headgroups. Membrane binding is also strong for beta-synuclein, phosphorylated alpha-synuclein, and a synuclein mutant that is associated with familial Parkinson's disease. In solution at less than 400 nM, synuclein has a tendency to undergo concentration-dependent oligomerization as determined by changes in intrinsic fluorescence and fluorescence resonance energy transfer. Above this concentration, the protein begins to aggregate into structures visible by light scattering. Although membrane binding does not affect the secondary structure of alpha-synuclein, it greatly inhibits the ability of this protein to self-associate. Taken together, our results indicate that pathological conditions may be associated with a disruption in synuclein-membrane interactions.

Topics: alpha-Synuclein; beta-Synuclein; Blotting, Western; Cell Membrane; Circular Dichroism; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Humans; Hydrogen-Ion Concentration; Lipids; Nerve Tissue Proteins; Neurodegenerative Diseases; Phosphatidylcholines; Phosphatidylethanolamines; Phosphorylation; Protein Binding; Protein Structure, Secondary; Protein Structure, Tertiary; Silver Staining; Spectrometry, Fluorescence; Synucleins

alpha-Synuclein is present in intracellular protein aggregates that are hallmarks of common neurodegenerative disorders including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. alpha-Synuclein is localized in neurons and presynaptic terminals. Under pathological conditions, however, it is also found in glia. The role of alpha-synuclein in glial cells and its relevance to the molecular pathology of neurodegenerative diseases is presently unclear. To investigate the consequence of alpha-synuclein overexpression in glia, we transfected U373 astrocytoma cells with vectors encoding wild-type human alpha-synuclein or C-terminally truncated synuclein fused to red fluorescent protein. alpha-synuclein immunocytochemistry of transfected astroglial cells revealed diffuse cytoplasmic labeling associated with discrete inclusions both within cell bodies and processes. Susceptibility to oxidative stress was increased in astroglial cells overexpressing alpha-synuclein, particularly in the presence of cytoplasmic inclusions. Furthermore, overexpression of alpha-synuclein induced apoptotic death of astroglial cells as shown by TUNEL staining. Our in vitro model is the first to replicate salient features of the glial pathology associated with alpha-synucleinopathies. It provides a simple testbed to further explore the cascade of events that leads to apoptotic glial cell death in some of these disorders; it may also be useful to assess the effects of therapeutic interventions including antioxidative and antiapoptotic strategies.

Topics: alpha-Synuclein; Apoptosis; Astrocytes; Cell Size; Green Fluorescent Proteins; Humans; Immunohistochemistry; Indicators and Reagents; L-Lactate Dehydrogenase; Luminescent Proteins; Nerve Degeneration; Nerve Tissue Proteins; Neurodegenerative Diseases; Oxidative Stress; Peptide Fragments; Protein Structure, Tertiary; Recombinant Fusion Proteins; Red Fluorescent Protein; Synucleins; Transfection; Tumor Cells, Cultured

Brain lesions containing filamentous and aggregated alpha-synuclein are hallmarks of neurodegenerative synucleinopathies. Oxidative stress has been implicated in the formation of these lesions. Using HEK 293 cells stably transfected with wild-type and mutant alpha-synuclein, we demonstrated that intracellular generation of nitrating agents results in the formation of alpha-synuclein aggregates. Cells were exposed simultaneously to nitric oxide- and superoxide-generating compounds, and the intracellular formation of peroxynitrite was demonstrated by monitoring the oxidation of dihydrorhodamine 123 and the nitration of alpha-synuclein. Light microscopy using antibodies against alpha-synuclein and electron microscopy revealed the presence of perinuclear aggregates under conditions in which peroxynitrite was generated but not when cells were exposed to nitric oxide- or superoxide-generating compounds separately. alpha-Synuclein aggregates were observed in 20-30% of cells expressing wild-type or A53T mutant alpha-synuclein and in 5% of cells expressing A30P mutant alpha-synuclein. No evidence of synuclein aggregation was observed in untransfected cells or cells expressing beta-synuclein. In contrast, selective inhibition of the proteasome resulted in the formation of aggregates detected with antibodies to ubiquitin in the majority of the untransfected cells and cells expressing alpha-synuclein. However, alpha-synuclein did not colocalize with these aggregates, indicating that inhibition of the proteasome does not promote alpha-synuclein aggregation. In addition, proteasome inhibition did not alter the steady-state levels of alpha-synuclein, but addition of the lysosomotropic agent ammonium chloride significantly increased the amount of alpha-synuclein, indicating that lysosomes are involved in degradation of alpha-synuclein. Our data indicate that nitrative and oxidative insult may initiate pathogenesis of alpha-synuclein aggregates.

Topics: alpha-Synuclein; Ammonium Chloride; beta-Synuclein; Cell Line; Cysteine Endopeptidases; Enzyme Inhibitors; Humans; Inclusion Bodies; Intracellular Fluid; Kidney; Lysosomes; Macromolecular Substances; Multienzyme Complexes; Nerve Tissue Proteins; Neurodegenerative Diseases; Nitrates; Nitric Oxide; Oxidants; Proteasome Endopeptidase Complex; Protein Binding; Superoxides; Synucleins; Transfection; Ubiquitins

Although alpha- and beta-synucleins are expressed predominantly in presynaptic nerve terminals, recent studies have demonstrated that alpha-synuclein is also expressed in cultured astrocytes and oligodendrocytes. We determined whether beta-synuclein might be expressed in astrocytes. Beta-synuclein mRNA and protein were detected in normal human astrocytes in culture, and immunofluorescent staining showed that beta-synuclein protein was expressed within the cytoplasm and nucleus. Furthermore, beta-synuclein immunoreactivity was present in astrocytes, but not in oligodendrocytes, in normal human brain tissues. Ultrastructurally, beta-synuclein immunoreactivity was found in the cytoplasm of astrocytes, in association with the plasma membrane, ribosomes, rough endoplasmic reticulum and the nuclear outer membrane. The novel expression of beta-synuclein in astrocytes may provide an important insight about the role of this protein.

Topics: alpha-Synuclein; Astrocytes; beta-Synuclein; Brain; Cell Compartmentation; Cells, Cultured; Gene Expression; Humans; Immunohistochemistry; Intracellular Membranes; Microscopy, Electron; Nerve Tissue Proteins; Neurodegenerative Diseases; RNA, Messenger; Synucleins

We characterized beta-synuclein, the non-amyloidogenic homolog of alpha-synuclein, as an inhibitor of aggregation of alpha-synuclein, a molecule implicated in Parkinson's disease. For this, doubly transgenic mice expressing human (h) alpha- and beta-synuclein were generated. In doubly transgenic mice, beta-synuclein ameliorated motor deficits, neurodegenerative alterations, and neuronal alpha-synuclein accumulation seen in halpha-synuclein transgenic mice. Similarly, cell lines transfected with beta-synuclein were resistant to alpha-synuclein accumulation. halpha-synuclein was coimmunoprecipitated with hbeta-synuclein in the brains of doubly transgenic mice and in the double-transfected cell lines. Our results raise the possibility that beta-synuclein might be a natural negative regulator of alpha-synuclein aggregation and that a similar class of endogenous factors might regulate the aggregation state of other molecules involved in neurodegeneration. Such an anti-amyloidogenic property of beta-synuclein might also provide a novel strategy for the treatment of neurodegenerative disorders.

Topics: alpha-Synuclein; Animals; Antiparkinson Agents; beta-Synuclein; Brain; Dimerization; Gene Expression; Humans; Immunosorbent Techniques; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Motor Activity; Nerve Tissue Proteins; Neurodegenerative Diseases; Recombinant Proteins; Synucleins; Transfection

alpha-Synuclein is a presynaptic terminal protein that accumulates abnormally in plaques in Alzheimer's disease (AD), in Lewy bodies in Lewy body disease (LBD) and in filamentous inclusions in multiple system atrophy. Since it has been previously shown that proteinase K or formic acid pretreatment enhances alpha-synuclein immunoreactivity in Lewy bodies and plaques, we hypothesized that the immunoreactivity in tangles, glial cells and Pick bodies might be revealed by such pretreatment. Brain sections from patients with AD, LBD, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Pick's disease were pretreated with proteinase K or formic acid and immunostained with antibodies against the N-terminal, C-terminal or non-amyloid beta component of AD amyloid (NAC) regions of alpha-synuclein. This study showed that after proteinase K (but not formic acid) pretreatment the anti-C terminus antibody immunostained neurofibrillary tangles of AD, PSP and CBD, and glial inclusions of PSP and CBD, as well as Pick bodies. Western blot analysis confirmed that in cases other than LBD, the anti-C terminus antibodies also recognized the native alpha-synuclein band and no cross-reactive bands were observed. In contrast, in LBD, after formic acid pretreatment with the anti-NAC antibody astroglial cells and granular neurons were immunostained. The N-terminal region antibody only recognized the lesions in LBD cases and not those of other neurodegenerative disorders. These results support the view that different fragments of alpha-synuclein might play an important role in the pathogenesis of several neurodegenerative disorders.

Topics: Aged; alpha-Synuclein; Brain; Humans; Immunohistochemistry; Lewy Bodies; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Synucleins

To elucidate the role of the synaptic protein alpha-synuclein in neurodegenerative disorders, transgenic mice expressing wild-type human alpha-synuclein were generated. Neuronal expression of human alpha-synuclein resulted in progressive accumulation of alpha-synuclein-and ubiquitin-immunoreactive inclusions in neurons in the neocortex, hippocampus, and substantia nigra. Ultrastructural analysis revealed both electron-dense intranuclear deposits and cytoplasmic inclusions. These alterations were associated with loss of dopaminergic terminals in the basal ganglia and with motor impairments. These results suggest that accumulation of wild-type alpha-synuclein may play a causal role in Parkinson's disease and related conditions.

Topics: alpha-Synuclein; Animals; Brain; Dopamine; Humans; Inclusion Bodies; Lewy Bodies; Lewy Body Disease; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Microscopy, Electron; Motor Activity; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Substantia Nigra; Synucleins; Tyrosine 3-Monooxygenase; Ubiquitins

Intracellular proteinaceous aggregates are hallmarks of many common neurodegenerative disorders, and recent studies have shown that alpha-synuclein is a major component of several pathological intracellular inclusions, including Lewy bodies in Parkinson's disease (PD) and glial cell inclusions in multiple system atrophy. However, the molecular mechanisms underlying alpha-synuclein aggregation into filamentous inclusions remain unknown. Since oxidative and nitrative stresses are potential pathogenic mediators of PD and other neurodegenerative diseases, we asked if oxidative and/or nitrative events alter alpha-synuclein and induce it to aggregate. Here we show that exposure of human recombinant alpha-synuclein to nitrating agents (peroxynitrite/CO(2) or myeloperoxidase/H(2)O(2)/nitrite) induces formation of nitrated alpha-synuclein oligomers that are highly stabilized due to covalent cross-linking via the oxidation of tyrosine to form o,o'-dityrosine. We also demonstrate that oxidation and nitration of pre-assembled alpha-synuclein filaments stabilize these filaments to withstand denaturing conditions and enhance formation of SDS-insoluble, heat-stable high molecular mass aggregates. Thus, these data suggest that oxidative and nitrative stresses are involved in mechanisms underlying the pathogenesis of Lewy bodies and glial cell inclusions in PD and multiple system atrophy, respectively, as well as alpha-synuclein pathologies in other synucleinopathies.

Topics: alpha-Synuclein; Electrophoresis, Polyacrylamide Gel; Humans; Nerve Tissue Proteins; Neurodegenerative Diseases; Nitrates; Oxidative Stress; Polymers; Recombinant Proteins; Synucleins; Tyrosine

alpha-, beta-, and gamma-Synuclein, a novel family of neuronal proteins, has become the focus of research interest because alpha-synuclein has been increasingly implicated in the pathogenesis of Parkinson's and Alzheimer's disease. However, the normal functions of the synucleins are still unknown. For this reason, we characterized alpha-, beta-, and gamma-synuclein expression in primary hippocampal neuronal cultures and showed that the onset of alpha- and beta-synuclein expression was delayed after synaptic development, suggesting that these synucleins may not be essential for synapse formation. In mature cultured primary neurons, alpha- and beta-synuclein colocalized almost exclusively with synaptophysin in the presynaptic terminal, whereas little gamma-synuclein was expressed at all. To assess the function of alpha-synuclein, we suppressed expression of this protein with antisense oligonucleotide technology. Morphometric ultrastructural analysis of the alpha-synuclein antisense oligonucleotide-treated cultures revealed a significant reduction in the distal pool of synaptic vesicles. These data suggest that one function of alpha-synuclein may be to regulate the size of distinct pools of synaptic vesicles in mature neurons.

Topics: alpha-Synuclein; Animals; beta-Synuclein; Cells, Cultured; gamma-Synuclein; Hippocampus; Nerve Tissue Proteins; Neurodegenerative Diseases; Oligonucleotides, Antisense; Presynaptic Terminals; Rats; Rats, Sprague-Dawley; Synaptic Vesicles; Synucleins

Neurodegeneration with brain iron accumulation, type 1 (NBIA 1), or Hallervorden-Spatz syndrome, is a rare neurodegenerative disorder characterized clinically by Parkinsonism, cognitive impairment, pseudobulbar features, as well as cerebellar ataxia, and neuropathologically by neuronal loss, gliosis, and iron deposition in the globus pallidus, red nucleus, and substantia nigra. The hallmark pathological lesions of NBIA 1 are axonal spheroids, but Lewy body (LB)-like intraneuronal inclusions, glial inclusions, and rare neurofibrillary tangles also occur. Here we show that there is an accumulation of alpha-synuclein (alphaS) in LB-like inclusions, glial inclusions, and spheroids in the brains of three NBIA 1 patients. Further, beta-synuclein (betaS) and gamma-synuclein (gammaS) immunoreactivity was detected in spheroids but not in LB-like or glial inclusions. Western blot analysis demonstrated high-molecular weight alphaS aggregates in the high-salt-soluble and Triton X-100-insoluble/sodium dodecyl sulfate-soluble fraction of the NBIA 1 brain. Significantly, the levels of alphaS were markedly reduced in the Triton X-100-soluble fractions compared to control brain, and unlike other synucleinopathies, insoluble alphaS did not accumulate in the formic acid-soluble fraction. These findings expand the concept of neurodegenerative synucleinopathies by implicating alphaS, betaS, and gammaS in the pathogenesis of NBIA 1.

Topics: Adolescent; Aged; alpha-Synuclein; Amyloid beta-Peptides; beta-Synuclein; Blotting, Western; Brain; Fatal Outcome; gamma-Synuclein; Humans; Immunohistochemistry; Infant; Iron; Nerve Tissue Proteins; Neurodegenerative Diseases; Synucleins; tau Proteins

The presynaptic protein alpha-synuclein is a prime suspect for contributing to Lewy pathology and clinical aspects of diseases, including Parkinson's disease, dementia with Lewy bodies, and a Lewy body variant of Alzheimer's disease. alpha-Synuclein accumulates in Lewy bodies and Lewy neurites, and two missense mutations (A53T and A30P) in the alpha-synuclein gene are genetically linked to rare familial forms of Parkinson's disease. Under control of mouse Thy1 regulatory sequences, expression of A53T mutant human alpha-synuclein in the nervous system of transgenic mice generated animals with neuronal alpha-synucleinopathy, features strikingly similar to those observed in human brains with Lewy pathology, neuronal degeneration, and motor defects, despite a lack of transgene expression in dopaminergic neurons of the substantia nigra pars compacta. Neurons in brainstem and motor neurons appeared particularly vulnerable. Motor neuron pathology included axonal damage and denervation of neuromuscular junctions in several muscles examined, suggesting that alpha-synuclein interfered with a universal mechanism of synapse maintenance. Thy1 transgene expression of wild-type human alpha-synuclein resulted in similar pathological changes, thus supporting a central role for mutant and wild-type alpha-synuclein in familial and idiotypic forms of diseases with neuronal alpha-synucleinopathy and Lewy pathology. These mouse models provide a means to address fundamental aspects of alpha-synucleinopathy and test therapeutic strategies.

Topics: alpha-Synuclein; Animals; Central Nervous System; Gene Expression Regulation; Humans; Lewy Bodies; Mice; Mice, Transgenic; Motor Activity; Motor Neurons; Movement Disorders; Mutation; Nerve Degeneration; Nerve Tissue Proteins; Neurodegenerative Diseases; Psychomotor Performance; Synucleins

Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of neurodegenerative synucleinopathies, and oxidative stress has been implicated in the pathogenesis of some of these disorders. Using antibodies to specific nitrated tyrosine residues in alpha-synuclein, we demonstrate extensive and widespread accumulations of nitrated alpha-synuclein in the signature inclusions of Parkinson's disease, dementia with Lewy bodies, the Lewy body variant of Alzheimer's disease, and multiple system atrophy brains. We also show that nitrated alpha-synuclein is present in the major filamentous building blocks of these inclusions, as well as in the insoluble fractions of affected brain regions of synucleinopathies. The selective and specific nitration of alpha-synuclein in these disorders provides evidence to directly link oxidative and nitrative damage to the onset and progression of neurodegenerative synucleinopathies.

Topics: alpha-Synuclein; Alzheimer Disease; Antibodies, Monoclonal; Blotting, Western; Brain; Brain Chemistry; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Immunohistochemistry; Lewy Bodies; Lewy Body Disease; Microscopy, Immunoelectron; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurons; Oxidative Stress; Parkinson Disease; Synucleins; Tyrosine

Reactive nitrogen species may play a mechanistic role in neurodegenerative diseases by posttranslationally altering normal brain proteins. In support of this hypothesis, we demonstrate that an anti-3-nitrotyrosine polyclonal antibody stains all of the major hallmark lesions of synucleinopathies including Lewy bodies, Lewy neurites and neuraxonal spheroids in dementia with Lewy bodies, the Lewy body variant of Alzheimer's disease, and neurodegeneration with brain iron accumulation type 1, as well as glial and neuronal cytoplasmic inclusions in multiple system atrophy. This antibody predominantly recognized nitrated alpha-synuclein when compared to other in vitro nitrated constituents of these pathological lesions, such as neurofilament subunits and microtubules. Collectively, these findings imply that alpha-synuclein is nitrated in pathological lesions. The widespread presence of nitrated alpha-synuclein in diverse intracellular inclusions suggests that oxidation/nitration is involved in the onset and/or progression of neurodegenerative diseases.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Antibodies; Blotting, Western; Brain Diseases; Female; Humans; Immunohistochemistry; Inclusion Bodies; Lewy Bodies; Male; Middle Aged; Nerve Tissue Proteins; Neurodegenerative Diseases; Neuroglia; Nitrates; Synucleins; Tissue Distribution; Tyrosine

Microtubule-associated protein tau forms neurofibrillary lesions in Alzheimer's disease and several other neurodegenerative disorders, such as Niemann-Pick disease type C, subacute sclerosing panencephalitis, argyrophilic grain disease, myotonic dystrophy and motor neuron disease with neurofibrillary tangles. In this study we have compared the characteristics of tau pathology in these diseases using immunohistochemistry and phosphorylation-dependent and phosphorylation-independent anti-tau antibodies. The pattern of staining for heparan sulphate and alpha-synuclein was also investigated. We show that in all of these diseases tau deposits were stained by all anti-tau antibodies used, with the exception of argyrophilic grains which do not stain with antibody 12E8, confirming our previous findings. Heparan sulphate staining was present to a variable extent in all of these diseases, with the exception of subacute sclerosing panencephalitis, in which no staining was observed. Heparan sulphate staining coexisted with tau staining. In some cases it was more extensive than the tau staining. Alpha-synuclein staining was present in presynaptic terminals with the exception of one case of Alzheimer's disease, in which alpha-synuclein-positive Lewy bodies were observed in the hippocampal formation. These findings indicate that tau deposits are antigenically similar in several neurodegenerative diseases and that tau staining is often associated with heparan sulphate staining, supporting the concept that heparan sulphate may be involved in the assembly of tau protein into filaments.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; alpha-Synuclein; Dementia; Female; Heparitin Sulfate; Humans; Immunohistochemistry; Male; Microtubule-Associated Proteins; Nerve Tissue Proteins; Neurodegenerative Diseases; Neurofibrils; Synucleins; tau Proteins

A family of homologous proteins known as alpha-, beta-, and gamma-synuclein are abundantly expressed in brain, especially in the presynaptic terminal of neurons. Although the precise function of these proteins remains unknown, alpha-synuclein has been implicated in synaptic plasticity associated with avian song learning as well as in the pathogenesis of Parkinson's disease (PD), dementia with LBs (DLB), some forms of Alzheimer's disease (AD), and multiple system atrophy (MSA). Since olfactory dysfunction is a common feature of these disorders and the olfactory receptor neurons (ORNs) of the olfactory epithelium (OE) regenerate throughout the lifespan, we used antibodies specific for alpha-, beta-, and gamma-synucleins to examine the olfactory mucosa of patients with PD, DLB, AD, MSA, and controls without a neurological disorder. Although antibodies to alpha- and beta-synucleins detected abnormal dystrophic neurites in the OE of patients with neurodegenerative disorders, similar pathology was also seen in the OE of controls. More significantly, we show here for the first time that alpha-, beta-, and gamma-synucleins are differentially expressed in cells of the OE and respiratory epithelium and that alpha-synuclein is the most abundant synuclein in the olfactory mucosa, where it is prominently expressed in ORNs. Moreover, alpha- and gamma-synucleins also were prominent in the OE basal cells, which include the progenitor cells of the ORNs in the OE. Thus, our data on synuclein expression within the OE may signify that synuclein plays a role in the regeneration and plasticity of ORNs in the adult human OE.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease; Female; gamma-Synuclein; Humans; Immunohistochemistry; Male; Middle Aged; Multiple System Atrophy; Nerve Tissue Proteins; Neurodegenerative Diseases; Olfactory Mucosa; Parkinson Disease; Phosphoproteins; Synucleins

In familial PD, a mutation of the alpha-synuclein gene has been identified. Alpha-synuclein also was revealed in Lewy bodies in idiopathic PD. Lewy bodies in neurodegeneration with brain iron accumulation type 1 (NBIA 1; Hallervorden-Spatz syndrome) were found to show immunostaining for alpha-synuclein/precursor of non-A beta component of Alzheimer's disease amyloid, indicating that alpha-synuclein is commonly associated with the formation of Lewy bodies in other sporadic and familial neurodegenerative diseases apart from PD.

Topics: Adult; alpha-Synuclein; Female; Humans; Immunohistochemistry; Iron; Lewy Bodies; Male; Nerve Tissue Proteins; Neurodegenerative Diseases; Pantothenate Kinase-Associated Neurodegeneration; Parkinson Disease; Synucleins; Ubiquitins

Alpha-synuclein (alpha-syn) protein and a fragment of it, called NAC, have been found in association with the pathological lesions of a number of neurodegenerative diseases. Recently, mutations in the alpha-syn gene have been reported in families susceptible to an inherited form of Parkinson's disease. We have shown that human wild-type alpha-syn, mutant alpha-syn(Ala30Pro) and mutant alpha-syn(Ala53Thr) proteins can self-aggregate and form amyloid-like filaments. Here we report that aggregates of NAC and alpha-syn proteins induced apoptotic cell death in human neuroblastoma SH-SY5Y cells. These findings indicate that accumulation of alpha-syn and its degradation products may play a major role in the development of the pathogenesis of these neurodegenerative diseases.

Topics: alpha-Synuclein; Amyloid; Apoptosis; Benzothiazoles; Biopolymers; Cell Nucleus; Cell Survival; Circular Dichroism; Humans; Microscopy, Electron; Mutation; Nerve Tissue Proteins; Neuroblastoma; Neurodegenerative Diseases; Neurons; Parkinson Disease; Peptides; Protein Structure, Secondary; Synucleins; Thiazoles; Tumor Cells, Cultured