Exogenous α-synuclein fibrils seed the formation of Lewy body-like intracellular inclusions in cultured cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 106; no. 47; pp. 20051 - 20056
• Main Authors: Luk, Kelvin C, Song, Cheng, O'Brien, Patrick, Stieber, Anna, Branch, Jonathan R, Brunden, Kurt R, Trojanowski, John Q, Lee, Virginia M.-Y
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 24.11.2009; National Acad Sciences
• Subjects: Aggregation; alpha-Synuclein - chemistry; alpha-Synuclein - genetics; alpha-Synuclein - metabolism; Amyloid - chemistry; Amyloid - metabolism; Biological Sciences; Cell culture techniques; Cell lines; Cells; Cells, Cultured; Cultured cells; cytoplasm; Cytoplasmic inclusions; Humans; Inclusion bodies; Inclusion Bodies - chemistry; Inclusion Bodies - metabolism; Inclusion Bodies - pathology; Inclusion Bodies - ultrastructure; Lewy bodies; Lewy Bodies - chemistry; Lewy Bodies - metabolism; Neurons; Neurons - cytology; Neurons - metabolism; Neurons - pathology; Parkinson disease; Parkinson Disease - metabolism; Parkinson Disease - pathology; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Solar fibrils
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.0908005106

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