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Neurobiology of Disease Apr 2016α-Synuclein is a conserved, abundantly expressed protein that is partially localized in pre-synaptic terminals in the central nervous system. The precise biological... (Review)
Review
α-Synuclein is a conserved, abundantly expressed protein that is partially localized in pre-synaptic terminals in the central nervous system. The precise biological function(s) and structure of α-synuclein are under investigation. Recently, the native conformation and the presence of naturally occurring multimeric assemblies have come under debate. These are important deliberations because α-synuclein assembles into highly organized amyloid-like fibrils and non-amyloid amorphous aggregates that constitute the neuronal inclusions in Parkinson's disease and related disorders. Therefore understanding the nature of the native and pathological conformations is pivotal from the standpoint of therapeutic interventions that could maintain α-synuclein in its physiological state. In this review, we will discuss the existing evidence that define the physiological states of α-synuclein and highlight how the inherent structural flexibility of this protein may be important in health and disease.
Topics: Animals; Humans; Models, Chemical; Nonlinear Dynamics; Protein Conformation; alpha-Synuclein
PubMed: 26747212
DOI: 10.1016/j.nbd.2015.12.018 -
Biomolecules Mar 2020Elucidating the structural details of proteins is highly valuable and important for the proper understanding of protein function. In the case of intrinsically disordered... (Review)
Review
Elucidating the structural details of proteins is highly valuable and important for the proper understanding of protein function. In the case of intrinsically disordered proteins (IDPs), however, obtaining the structural details is quite challenging, as the traditional structural biology tools have only limited use. Nuclear magnetic resonance (NMR) is a unique experimental tool that provides ensemble conformations of IDPs at atomic resolution, and when studying IDPs, a slightly different experimental strategy needs to be employed than the one used for globular proteins. We address this point by reviewing many NMR investigations carried out on the α-synuclein protein, the aggregation of which is strongly correlated with Parkinson's disease.
Topics: Humans; Nuclear Magnetic Resonance, Biomolecular; Parkinson Disease; Protein Aggregates; Protein Structure, Secondary; alpha-Synuclein
PubMed: 32164323
DOI: 10.3390/biom10030428 -
ChemPlusChem Oct 2023Tau and α-synuclein are proteins involved in pathologies known as tauopathies and synucleinopathies, respectively. Moreover, evidence shows that there is a crosstalk...
Tau and α-synuclein are proteins involved in pathologies known as tauopathies and synucleinopathies, respectively. Moreover, evidence shows that there is a crosstalk between them as is seen in the brains of individuals with sporadic neurodegenerative disorders. Based on that, we present data showing that the hydrophobic α-peptide VTGVTAVAQKTV induces the aggregation of the full-length tau fragment in the absence of heparin assessed by ThT. Moreover, AFM images reveal the presence of straight filaments and amorphous aggregates of full-length tau in the presence of the α-peptide. Additionally, ITC experiments showed the interaction of the α-peptide with tau full-length (441 amino acids),4R (amino acids from 244 to 369), and both hexapeptides VQIINK and VQIVYK through hydrophobic interactions. The Raman spectroscopy spectra showed conformational changes in the Amide region in the aggregates formed with full-length tau and α-syn peptide. Furthermore, the incubation of extracellular aggregates with N2a cells showed morphological differences in the cellular body and the nucleus suggesting cell death. Moreover,, the incubation of different types of aggregates in cell culture provokes the release of Lactate dehydrogenase (LDH). Altogether, we found that α-synuclein peptide can drive the aggregation of full-length tau-provoking morphological and structural changes evoking cytotoxic effects.
Topics: Humans; alpha-Synuclein; tau Proteins; Peptides; Amino Acids; Hydrophobic and Hydrophilic Interactions
PubMed: 37708459
DOI: 10.1002/cplu.202300257 -
Chemical Record (New York, N.Y.) Feb 2024Parkinson's disease is a yet incurable, age-related neurodegenerative disorder characterized by the aggregation of small neuronal protein α-synuclein into amyloid... (Review)
Review
Parkinson's disease is a yet incurable, age-related neurodegenerative disorder characterized by the aggregation of small neuronal protein α-synuclein into amyloid fibrils. Inhibition of this process is a prospective strategy for developing a disease-modifying treatment. We overview here small molecule, peptide, and protein inhibitors of α-synuclein fibrillization reported to date. Special attention was paid to the specificity of inhibitors and critical analysis of their action mechanisms. Namely, the importance of oxidation of polyphenols and cross-linking of α-synuclein into inhibitory dimers was highlighted. We also compared strategies of targeting monomeric, oligomeric, and fibrillar α-synuclein species, thoroughly discussed the strong and weak sides of different approaches to testing the inhibitors.
Topics: Humans; alpha-Synuclein; Parkinson Disease
PubMed: 37919046
DOI: 10.1002/tcr.202300282 -
Cell Death & Disease Jul 2012The aggregation, deposition, and dysfunction of alpha-synuclein (aSyn) are common events in neurodegenerative disorders known as synucleinopathies. These include... (Review)
Review
The aggregation, deposition, and dysfunction of alpha-synuclein (aSyn) are common events in neurodegenerative disorders known as synucleinopathies. These include Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. A growing body of knowledge on the biology of aSyn is emerging and enabling novel hypotheses to be tested. In particular, the hypothesis that aSyn is secreted from neurons, thus contributing to the spreading of pathology not only in the brain but also in other organs, is gaining momentum. Nevertheless, the precise mechanism(s) of secretion, as well as the consequences of extracellular aSyn species for neighboring cells are still unclear. Here, we review the current literature and integrate existing data in order to propose possible mechanisms of secretion, cell dysfunction, and death. Ultimately, the complete understanding of these processes might open novel avenues for the development of new therapeutic strategies.
Topics: Animals; Apoptosis; Humans; Parkinson Disease; Protein Folding; alpha-Synuclein
PubMed: 22825468
DOI: 10.1038/cddis.2012.94 -
Methods (San Diego, Calif.) Mar 2011This review describes different ways to achieve and monitor reproducible aggregation of α-synuclein, a key protein in the development of Parkinson's disease. For most... (Review)
Review
This review describes different ways to achieve and monitor reproducible aggregation of α-synuclein, a key protein in the development of Parkinson's disease. For most globular proteins, aggregation is promoted by partially denaturing conditions which compromise the native state without destabilizing the intermolecular contacts required for accumulation of regular amyloid structure. As a natively disordered protein, α-synuclein can fibrillate under physiological conditions and this process is actually stimulated by conditions that promote structure formation, such as low pH, ions, polyamines, anionic surfactants, fluorinated alcohols and agitation. Reproducibility is a critical issue since α-synuclein shows erratic fibrillation behavior on its own. Agitation in combination with glass beads significantly reduces the variability of aggregation time curves, but the most reproducible aggregation is achieved by sub-micellar concentrations of SDS, which promote the rapid formation of small clusters of α-synuclein around shared micelles. Although the fibrils produced this way have a different appearance and secondary structure, they are rich in cross-β structure and are amenable to high-throughput screening assays. Although such assays at best provide a very simplistic recapitulation of physiological conditions, they allow the investigator to focus on well-defined molecular events and may provide the opportunity to identify, e.g. small molecule inhibitors of aggregation that affect these steps. Subsequent experiments in more complex cellular and whole-organism environments can then validate whether there is any relation between these molecular interactions and the broader biological context.
Topics: Amyloid; Humans; Parkinson Disease; Reproducibility of Results; Research Design; Sodium Dodecyl Sulfate; Trifluoroethanol; alpha-Synuclein
PubMed: 21163351
DOI: 10.1016/j.ymeth.2010.12.008 -
Acta Neurologica Scandinavica Aug 2014Parkinson's disease (PD) is neuropathologically characterized as an alpha-synucleinopathy. Alpha-synuclein-containing inclusions are stained as Lewy bodies and Lewy... (Review)
Review
Parkinson's disease (PD) is neuropathologically characterized as an alpha-synucleinopathy. Alpha-synuclein-containing inclusions are stained as Lewy bodies and Lewy neurites in the brain, which are the pathological hallmark of PD. However, alpha-synuclein-containing inclusions in PD are not restricted to the central nervous system, but are also found in peripheral tissues. Alpha-synuclein levels can also be measured in body fluids. The aim of this study was to conduct a systematic review of available evidence to determine the utility of alpha-synuclein as a peripheral biomarker of PD. We searched PubMed (1948 to 26 May 2013), Embase (1974 to 26 May 2013), the Cochrane Library (up to 26 May 2013), LILACS (up to 26 May 2013) and CINAHL (up to 26 May 2013) for the studies of alpha-synuclein in peripheral tissues or body fluids in PD. A total of 49 studies fulfilled the search criteria. Peripheral tissues such as colonic mucosa showed a sensitivity of 42-90% and a specificity of 100%; submandibular salivary glands showed sensitivity and specificity of 100%; skin biopsy showed 19% sensitivity and 80% specificity in detecting alpha-synuclein pathology. CSF alpha-synuclein had 71-94% sensitivity and 25-53% specificity for distinguishing PD from controls. Plasma alpha-synuclein had 48-53% sensitivity and 69-85% specificity. Neither plasma nor CSF alpha-synuclein is presently a reliable marker of PD. This differs from alpha-synuclein in solid tissue samples of the enteric and autonomic nervous system, which offer some potential as a surrogate marker of brain synucleinopathy.
Topics: Biomarkers; Humans; Parkinson Disease; alpha-Synuclein
PubMed: 24702516
DOI: 10.1111/ane.12247 -
Cell Death & Disease Feb 2020Aggregation of alpha-synuclein (αSyn) is a crucial event underlying the pathophysiology of synucleinopathies. The existence of various intracellular and extracellular...
Aggregation of alpha-synuclein (αSyn) is a crucial event underlying the pathophysiology of synucleinopathies. The existence of various intracellular and extracellular αSyn species, including cleaved αSyn, complicates the quest for an appropriate therapeutic target. Hence, to develop efficient disease-modifying strategies, it is fundamental to achieve a deeper understanding of the relevant spreading and toxic αSyn species. Here, we describe comparative and proof-of-principle approaches to determine the involvement of αSyn fragments in intercellular spreading. We demonstrate that two different αSyn fragments (1-95 and 61-140) fulfill the criteria of spreading species. They efficiently instigate formation of proteinase-K-resistant aggregates from cell-endogenous full-length αSyn, and drive it into different aggregation pathways. The resulting aggregates induce cellular toxicity. Strikingly, these aggregates are only detectable by specific antibodies. Our results suggest that αSyn fragments might be relevant not only for spreading, but also for aggregation-fate determination and differential strain formation.
Topics: Cell Line; Extracellular Space; Gene Knockout Techniques; Humans; Neurons; Peptide Fragments; Protein Aggregates; Protein Aggregation, Pathological; Protein Domains; Protein Transport; Recombinant Proteins; alpha-Synuclein
PubMed: 32015326
DOI: 10.1038/s41419-020-2285-7 -
FASEB Journal : Official Publication of... Feb 2019The pathophysiology of Parkinson's disease is characterized by the abnormal accumulation of α-synuclein (α-Syn), eventually resulting in the formation of Lewy bodies...
The pathophysiology of Parkinson's disease is characterized by the abnormal accumulation of α-synuclein (α-Syn), eventually resulting in the formation of Lewy bodies and neurites in surviving neurons in the brain. Although α-Syn aggregation has been extensively studied in vitro, there is limited in vivo knowledge on α-Syn aggregation. Here, we used the powerful genetics of Drosophila melanogaster and developed an in vivo assay to monitor α-Syn accumulation by using a bimolecular fluorescence complementation assay. We found that both genetic and pharmacologic manipulations affected α-Syn accumulation. Interestingly, we also found that alterations in the cellular protein degradation mechanisms strongly influenced α-Syn accumulation. Administration of compounds identified as risk factors for Parkinson's disease, such as rotenone or heavy metal ions, had only mild or even no impact on α-Syn accumulation in vivo. Finally, we show that increasing phosphorylation of α-Syn at serine 129 enhances the accumulation and toxicity of α-Syn. Altogether, our study establishes a novel model to study α-Syn accumulation and illustrates the complexity of manipulating proteostasis in vivo.-Prasad, V., Wasser, Y., Hans, F., Goswami, A., Katona, I., Outeiro, T. F., Kahle, P. J., Schulz, J. B., Voigt, A. Monitoring α-synuclein multimerization in vivo.
Topics: Amyloid; Animals; Disease Models, Animal; Drosophila melanogaster; Male; Phosphorylation; Protein Multimerization; Reactive Oxygen Species; Serine; alpha-Synuclein
PubMed: 30252534
DOI: 10.1096/fj.201800148RRR -
Traffic (Copenhagen, Denmark) Jul 2022Alpha-synuclein (α-Syn), an intrinsically disordered protein (IDP), is associated with neurodegenerative disorders, including Parkinson's disease (PD or other...
Alpha-synuclein (α-Syn), an intrinsically disordered protein (IDP), is associated with neurodegenerative disorders, including Parkinson's disease (PD or other α-synucleinopathies. Recent investigations propose the transmission of α-Syn protein fibrils, in a prion-like manner, by entering proximal cells to seed further fibrillization in PD. Despite the recent advances, the mechanisms by which extracellular protein aggregates internalize into the cells remain poorly understood. Using a simple cell-based model of human neuroblastoma-derived differentiated neurons, we present the cellular internalization of α-Syn PFF to check cellular uptake and recycling kinetics along with the standard endocytic markers Transferrin (Tf) marking clathrin-mediated endocytosis (CME) and Galectin3 (Gal3) marking clathrin-independent endocytosis (CIE). Specific inhibition of endocytic pathways using chemical inhibitors reveals no significant involvement of CME, CIE and caveolae-mediated endocytosis (CvME). A substantial reduction in cellular uptake was observed after perturbation of actin polymerization and treatment with macropinosomes inhibitor. Our results show that α-Syn PFF mainly internalizes into the SH-SY5Y cells and differentiated neurons via the macropinocytosis pathway. The elucidation of the molecular and cellular mechanism involved in the α-Syn PFF internalization will help improve the understanding of α-synucleinopathies including PD, and further design specific inhibitors for the same.
Topics: Actins; Clathrin; Humans; Neuroblastoma; Neurons; Synucleinopathies; alpha-Synuclein
PubMed: 35604355
DOI: 10.1111/tra.12859