title: Lewy body-like α-synuclein aggregates resist degradation and impair macroautophagy.
abstract: Cytoplasmic α-synuclein (α-syn) aggregates, referred to as Lewy bodies, are pathological hallmarks of a number of neurodegenerative diseases, most notably Parkinson disease. Activation of macroautophagy is suggested to facilitate degradation of certain proteinaceous inclusions, but it is unclear if this pathway is capable of degrading α-syn aggregates. Here, we examined this issue by utilizing cellular models in which intracellular Lewy body-like α-syn inclusions accumulate after internalization of pre-formed α-syn fibrils into α-syn-expressing HEK293 cells or cultured primary neurons. We demonstrate that α-syn inclusions cannot be effectively degraded, even though they co-localize with essential components of both the autophagic and proteasomal protein degradation pathways. The α-syn aggregates persist even after soluble α-syn levels have been substantially reduced, suggesting that once formed, the α-syn inclusions are refractory to clearance. Importantly, we also find that α-syn aggregates impair overall macroautophagy by reducing autophagosome clearance, which may contribute to the increased cell death that is observed in aggregate-bearing cells.
authors.affiliation: Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Selcuk A
authors.initials: SA
authors.lastname: Tanik
authors.forename: Christine E
authors.initials: CE
authors.lastname: Schultheiss
authors.forename: Laura A
authors.initials: LA
authors.lastname: Volpicelli-Daley
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Brunden
authors.forename: Virginia M Y
authors.initials: VM
authors.lastname: Lee
mesh_terms: D000818:Animals; D001343:Autophagy; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D016631:Lewy Bodies / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008954:Models, Biological; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D010300:Parkinson Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D059748:Proteolysis; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051844:alpha-Synuclein; D046988:Proteasome Endopeptidase Complex
keywords: Aggregation; Autophagy; Parkinson Disease; Protein Degradation; α-Synuclein