Novel self-replicating ?-synuclein polymorphs that escape ThT monitoring can spontaneously emerge and acutely spread in neurons.

ABSTRACT: The conformational strain diversity characterizing ?-synuclein (?-syn) amyloid fibrils is thought to determine the different clinical presentations of neurodegenerative diseases underpinned by a synucleinopathy. Experimentally, various ?-syn fibril polymorphs have been obtained from distinct fibrillization conditions by altering the medium constituents and were selected by amyloid monitoring using the probe thioflavin T (ThT). We report that, concurrent with classical ThT-positive products, fibrillization in saline also gives rise to polymorphs invisible to ThT (?^-). The generation of ?^- fibril polymorphs is stochastic and can skew the apparent fibrillization kinetics revealed by ThT. Their emergence has thus been ignored so far or mistaken for fibrillization inhibitions/failures. They present a yet undescribed atomic organization and show an exacerbated propensity toward self-replication in cortical neurons, and in living mice, their injection into the substantia nigra pars compacta triggers a synucleinopathy that spreads toward the dorsal striatum, the nucleus accumbens, and the insular cortex.

SUBMITTER: De Giorgi F 

PROVIDER: S-EPMC7852382 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature