Optical structural analysis of individual α-synuclein oligomers

This study is supported by the Michael J. Fox Foundation (10200); The Royal Society with a University Research Fellowship (UF120277) (S.F.L.); a Marie‐Curie Individual Fellowship (S.D.); the Boehringer Ingelheim Fonds (P.F.), the Studienstiftung des Deutschen Volkes (P.F.); the UK Biotechnology and Biological Sciences Research Council (C.M.D.); the Wellcome Trust (C.M.D.); the Cambridge Centre for Misfolding Diseases (P.F. and C.M.D.), and the Royal Society and the European Research Council with an ERC Advanced Grant (669237) (D.K.).Small aggregates of misfolded proteins play a key role in neurodegenerative disorders. Such species have proved difficult to study due to the lack of suitable methods capable of resolving these heterogeneous aggregates, which are smaller than the optical diffraction limit. We demonstrate here an all-optical fluorescence microscopy method to characterise the structure of individual protein aggregates based on the fluorescence anisotropy of dyes such as thioflavin-T, and show that this technology is capable of studying oligomers in human biofluids such as cerebrospinal fluid. We first investigated in vitro the structural changes in individual oligomers formed during the aggregation of recombinant α-synuclein. By studying the diffraction-limited aggregates we directly evaluated their structural conversion and correlated this with the potential of aggregates to disrupt lipid bilayers. We finally characterised the structural features of aggregates present in cerebrospinal fluid of Parkinson's disease patients and age-matched healthy controls.Publisher PDFPeer reviewe