Seeded Propagation Of Alpha-Synuclein Aggregation In Mouse Brain Using Protein Misfolding Cyclic Amplification

alpha-Synuclein (alpha-syn) protein aggregation is associated with several neurodegenerative disorders collectively referred to as synucleinopathies, including Parkinson's disease. We used protein misfolding cyclic amplification (PMCA) to study alpha-syn aggregation in brain homogenates of wild-type or transgenic mice expressing normal (D line) or A53T mutant (M83 line) human alpha-syn. We found that sonication-incubation cycles of M83 mouse brain gradually produce large quantities of SDS-resistant alpha-syn aggregates, involving both human and mouse proteins. These PMCA products, containing partially proteinase K-resistant alpha-syn species, are competent to accelerate the onset of neurologic symptoms after intracerebral inoculation to young M83 mice and to seed aggregate formation of alpha-syn following PMCA, including in D and wild-type mouse brain substrates. PMCA seeding activity in the M83 diseased brain correlates positively with regions mostly targeted by the alpha-syn pathology in this model. Our data indicate that similar to prions, PMCA can reproduce some characteristics of alpha-syn aggregation and seeded propagation in vitro in a complex milieu. This opens new opportunities for the molecular study of synucleinopathies.