Luk, K. C. et al. Exogenous α-synuclein fibrils seed the formation of Lewy body-like intracellular inclusions in cultured cells. Proc. Natl Acad. Sci. USA 106, 20051-20056

Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Center for Neurodegenerative Disease Research, Institute on Aging, Philadelphia, PA 19104-4283, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 11/2009; 106(47):20051-6. DOI: 10.1073/pnas.0908005106
Source: PubMed


Cytoplasmic inclusions containing alpha-synuclein (alpha-Syn) fibrils, referred to as Lewy bodies (LBs), are the signature neuropathological hallmarks of Parkinson's disease (PD). Although alpha-Syn fibrils can be generated from recombinant alpha-Syn protein in vitro, the production of fibrillar alpha-Syn inclusions similar to authentic LBs in cultured cells has not been achieved. We show here that intracellular alpha-Syn aggregation can be triggered by the introduction of exogenously produced recombinant alpha-Syn fibrils into cultured cells engineered to overexpress alpha-Syn. Unlike unassembled alpha-Syn, these alpha-Syn fibrils "seeded" recruitment of endogenous soluble alpha-Syn protein and their conversion into insoluble, hyperphosphorylated, and ubiquitinated pathological species. Thus, this cell model recapitulates key features of LBs in human PD brains. Also, these findings support the concept that intracellular alpha-Syn aggregation is normally limited by the number of active nucleation sites present in the cytoplasm and that small quantities of alpha-Syn fibrils can alter this balance by acting as seeds for aggregation.

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Available from: Kelvin Luk, Feb 04, 2015
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    • "a-synuclein protein is basically composed of three parts: one lysine amino terminal, which may be associated with the membranes; an acid carbonyl end, which controls the cell nuclear localization and interacts with some small molecules (Ulmer et al. 2005); and the nonamyloid-b component of AD amyloid plaques (NAC) region, which is also the central region of a-synuclein (Ueda et al. 1993). The NAC region is a highly hydrophobic region, and it was found to be closely related to the a-synuclein aggregation (El-Agnaf et al. 1998a,b; Giasson et al. 2001; Luk et al. 2009). In non-denatured condition, a-synuclein mainly exists in a stable and unfolded monomer status (Weinreb et al. 1996; Eliezer et al. 2001). "
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    ABSTRACT: Parkinson's disease (PD) is cited to be the second most common neuronal degenerative disorders; however, the exact mechanism of PD is still unclear. α-synuclein is one of the key proteins in PD pathogenesis as it's the main component of the PD hallmark Lewy bodies (LBs). Nowadays, the study of α-synuclein phosphorylation mechanism related to the PD pathology has become a research hotspot, given that 90% of α-synuclein deposition in LBs is phosphorylated at Ser129, whereas in normal brains, only 4% or less of α-synuclein is phosphorylated at the residue. Here, we review the related study of PD pathological mechanism involving the phosphorylation of α-synuclein mainly at Ser129, Ser87 and Tyr125 residues in recent years, as well as some explorations relating to potential clinical application, in an attempt to describe the development and implication for the mechanism and therapy of PD. Given that some of the studies have yielded paradoxical results, there is need for more comprehensive research in the filed. The phosphorylation of α-synuclein might provide a breakthrough for PD mechanism study and even supply a new therapeutic strategy. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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    • "As PD evolves, aggregation spreads from the brainstem to the substantia nigra, areas of the midbrain and basal forebrain, eventually reaching the neocortex (Braak et al. 2003). Although misfolded proteins can aggregate by template replication in a prion-like manner (Luk et al. 2009), it is not known what initiates or 'seeds' misfolding, converts containment to progression or drives progression. Enteric α-synuclein aggregates are described with local inflammation in the gut, both clinical and experimental colitis (Grathwohl et al. 2013). "
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    • "Several others were also able to verify those observations with synthetic fibrils (Danzer et al., 2009; Luk et al., 2009; Volpicelli- Daley et al., 2011) or by co-culture experiments using different CNS cell types (Hansen et al., 2011). Transmission to second order neurons through anterograde axonal transport by live-cell imaging and immunofluorescence was also observed (Freundt et al., 2012). "
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    ABSTRACT: Prion diseases or Transmissible Spongiform Encephalopathies (TSEs) are a group of fatal neurodegenerative disorders affecting several mammalian species being Creutzfeldt-Jacob Disease (CJD) the most representative in human beings, scrapie in ovine, Bovine Spongiform Encephalopathy (BSE) in bovine and Chronic Wasting Disease (CWD) in cervids. As stated by the "protein-only hypothesis", the causal agent of TSEs is a self-propagating aberrant form of the prion protein (PrP) that through a misfolding event acquires a β-sheet rich conformation known as PrP(Sc) (from scrapie). This isoform is neurotoxic, aggregation prone and induces misfolding of native cellular PrP. Compelling evidence indicates that disease-specific protein misfolding in amyloid deposits could be shared by other disorders showing aberrant protein aggregates such as Alzheimer's Disease (AD), Parkinson's Disease (PD), Amyotrophic lateral sclerosis (ALS) and systemic Amyloid A amyloidosis (AA amyloidosis). Evidences of shared mechanisms of the proteins related to each disease with prions will be reviewed through the available in vivo models. Taking prion research as reference, typical prion-like features such as seeding and propagation ability, neurotoxic species causing disease, infectivity, transmission barrier and strain evidences will be analyzed for other protein-related diseases. Thus, prion-like features of amyloid β peptide and tau present in AD, α-synuclein in PD, SOD-1, TDP-43 and others in ALS and serum α-amyloid (SAA) in systemic AA amyloidosis will be reviewed through models available for each disease. Copyright © 2015. Published by Elsevier B.V.
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