Screening For Active Anti-prion Chinese Herbal Extracts Utilizing Drug-sensitive Yeast Prion Model

A series of fatal transmissible spongiform encephalopathies (TSE) in mammals are all caused by prions. Unfortunately, to date there is still no efficient treatments and drugs for prion diseases. In biological and medical research areas, screening for effective treatments and drugs against prion diseases is a constant research hotspot. In recent years, The anti-prion drug screening model based on yeast was established, which was proved to be an effective, safe and fast anti-prion drug candidates screening mode.The current anti-prion drug screening model works through phenotype change from white to red of wild-type yeast strains to isolate active anti-prion drug candidates, nevertheless, the wild-type yeast strains were less sensitive to drugs, which could lead to some mild drugs could not be screened.This research was aimed at isolating Chinene herbal extracts against prions by using drug-sensitive yeast prion. Firstly, by comparing to the difference in phenotype, growth characteristics and drug sensitivity between the NGMC, SSA1-21, SSBΔ, ERG6Δstrains and wild-type yeast prion, we identified the ERG6Δstrains was fit for isolating active anti-prion Chinene herbal extracts.Secondly, we assessed the anti-prion activity of 31 Chinese herbal extracts through the liquid culture using drug-sensitive ERG6Δstrains. The results showed that the extracts of Zanthoxylum nitidum, tobacco, Schisandra chinensis and Rhizoma Atractylodis Macrocephalae were effective in curing yeast prions.Finally, phenotypic analysis and semi-denaturing agarose gel electrophoresis followed by western bolt method (SDD-AGE/western bolt) at protein levels was carried on quantitative analyzing the anti-prion effects of Zanthoxylum nitidum extracts, the results showed that: after a five-days treatment in liquid medium containing 15 mg/ml Zanthoxylum nitidum extracts, more than 92.6% of the cells were cured. Further analysis by ultilzing phenotypic and SDD-AGE/western bolt assay confirmed that the Zanthoxylum nitidum extracts were active in curing yeast prion. To sum up, it could be concluded that the yeast prion ERG6Δwas fit for the screening for anti-prion herbal extracts in large-scale, and the extracts of Zanthoxylum nitidum, tobacco, Schisandra chinensis and Rhizoma Atractylodis Macrocephalae had different effect on curing yeast prion respectively. We also quantitatively analyzed the anti-prion effects of Zanthoxylum nitidum extracts, the results showed that: after a five-days treatment in liquid medium containing 15 mg/ml Zanthoxylum nitidum extracts, more than 92.6% of the cells were cured. Further analysis by ultilzing phenotypic and SDD-AGE/western bolt assay confirmed that the Zanthoxylum nitidum extracts were active in curing yeast prion. This research not only accumulated experimental data for the anti-prion effects of traditional Chinese medicine, but also provided a new direction for the anti-prion drug candidates screening.