A novel yeast-based screening system for potential compounds that can alleviate human α-synuclein toxicity

Aims: This study aimed to establish a yeast-based screening system for potential compounds that can alleviate the toxicity of α-synuclein (α-syn), a neuropathological hallmark of Parkinson's disease, either inhibition of α-syn aggregation or promotion of ubiquitin-mediated degradation of α-syn.

Methods and results: A powerful yeast-based screening assay using the rsp5^A401E -mutant strain, which is hypersensitive to α-syn aggregation, was established by two-step gene replacement and further overexpressed the GFP-fused α-syn in the drug-sensitive yeast strain with a galactose-inducible multicopy plasmid. The rsp5^A401E -mutant strain treated with baicalein, a known α-syn aggregation inhibitor, showed better α-syn toxicity alleviation than the same background wild type strain as accessed by comparison on the reduction kinetics of viable dye resazurin fluorometrically (λ_ex 540/λ_em 590 nm). The rsp5^A401E -mutant yeast-based assay system showed high sensitivity as it could detect as low as 3.13 µmol l^-1 baicalein, the concentration that lower than previously report detected by the in vitro assay.

Conclusions: Our yeast-based system has been effective for screening potential compounds that can alleviate α-syn toxicity with high sensitivity and specificity.

Significance and impact of the study: Yeast-based assay system can be used to discover novel neuroprotective drug candidates which may be either efficiently suppress-α-syn aggregation or enhance ubiquitin-dependent degradation.