Ethanol induces autophagy regulated by mitochondrial ROS in saccharomyces cerevisiae

Abstract

Ethanol accumulation inhibited the growth of Saccharomyces cerevisiae during wine fermentation. Autophagy and the release of reactive oxygen species (ROS) were also induced under ethanol stress. However, the relation between autophagy and ethanol stress was still unclear. In this study, expression of the autophagy genes ATG1 and ATG8 and the production of ROS under ethanol treatment in yeast were measured. The results showed that ethanol stress very significantly induced expression of the ATG1 and ATG8 genes and the production of hydrogen peroxide (H2O2) and superoxide anion (O2·-). Moreover, the atg1 and atg8 mutants aggregated more H2O2 and O2·- than the wild-type yeast. In addition, inhibitors of the ROS scavenging enzyme induced expression of the ATG1 and ATG8 genes by increasing the levels of H2O2 and O2·-. In contrast, glutathione (GSH) and N-acetylcystine (NAC) decreased ATG1 and ATG8 expression by reducing H2O2 and O2·- production. Rapamycin and 3-methyladenine also caused an obvious change in autophagy levels and simultaneously altered the release of H2O2 and O2·-. Finally, inhibitors of the mitochondrial electron transport chain (mtETC) increased the production of H2O2 and O2·- and also promoted expression levels of the ATG1 and ATG8 genes. In conclusion, ethanol stress induced autophagy which was regulated by H2O2 and O2·- derived from mtETC, and in turn, the autophagy contributed to the elimination H2O2 and O2·-.