s41593-022-01140-3 (2).pdf (17.22 MB)
Pathological structural conversion of α-synuclein at the mitochondria induces neuronal toxicity.
journal contributionposted on 2022-09-08, 10:28 authored by Minee L Choi, Alexandre Chappard, Bhanu P Singh, Catherine Maclachlan, Margarida Rodrigues, Evgeniya I Fedotova, Alexey V Berezhnov, Suman De, Christopher J Peddie, Dilan Athauda, Gurvir S Virdi, Weijia Zhang, James R Evans, Anna I Wernick, Zeinab Shadman Zanjani, Plamena R Angelova, Noemi Esteras, Andrey Y Vinokurov, Katie Morris, Kiani Jeacock, Laura Tosatto, Daniel Little, Paul Gissen, David J Clarke, Tilo Kunath, Lucy Collinson, David Klenerman, Andrey Y Abramov, Mathew H Horrocks, Sonia Gandhi
Aggregation of alpha-synuclein (α-Syn) drives Parkinson's disease (PD), although the initial stages of self-assembly and structural conversion have not been directly observed inside neurons. In this study, we tracked the intracellular conformational states of α-Syn using a single-molecule Förster resonance energy transfer (smFRET) biosensor, and we show here that α-Syn converts from a monomeric state into two distinct oligomeric states in neurons in a concentration-dependent and sequence-specific manner. Three-dimensional FRET-correlative light and electron microscopy (FRET-CLEM) revealed that intracellular seeding events occur preferentially on membrane surfaces, especially at mitochondrial membranes. The mitochondrial lipid cardiolipin triggers rapid oligomerization of A53T α-Syn, and cardiolipin is sequestered within aggregating lipid-protein complexes. Mitochondrial aggregates impair complex I activity and increase mitochondrial reactive oxygen species (ROS) generation, which accelerates the oligomerization of A53T α-Syn and causes permeabilization of mitochondrial membranes and cell death. These processes were also observed in induced pluripotent stem cell (iPSC)-derived neurons harboring A53T mutations from patients with PD. Our study highlights a mechanism of de novo α-Syn oligomerization at mitochondrial membranes and subsequent neuronal toxicity.