A yeast-based model of alpha-synucleinopathy identifies compounds with therapeutic potential.

We have developed a yeast-based model recapitulating neurotoxicity of alpha-synuclein fibrilization. This model recognized metal ions, known risk factors of alpha-synucleinopathy, as stimulators of alpha-synuclein aggregation and cytotoxicity. Elimination of Yca1 caspase activity augmented both cytotoxicity and inclusion body formation, suggesting the involvement of apoptotic pathway components in toxic alpha-synuclein amyloidogenesis. Deletion of hydrophobic amino acids at positions 66-74 in alpha-synuclein reduced its cytotoxicity but, remarkably, did not lower the levels of insoluble alpha-synuclein, indicating that noxious alpha-synuclein species are different from insoluble aggregates. A compound screen aimed at finding molecules with therapeutic potential identified flavonoids with strong activity to restrain alpha-synuclein toxicity. Subsequent structure-activity analysis elucidated that these acted by virtue of anti-oxidant and metal-chelating activities. In conclusion, this yeast-cell model as presented allows not only fundamental studies related to mechanisms of alpha-synuclein-instigated cellular degeneration, but is also a valid high-throughput identification tool for novel neuroprotective agents.