RNA-Seq identifies redox balance related gene expression alterations under acute cadmium exposure in yeast

The nonessential metal cadmium can cause cell toxicity and is associated with a range of human diseases including cardiovascular diseases, neurodegenerative diseases and cancers. In this study, cadmium-induced global gene expression profile of yeast was obtained using RNA Sequencing (RNA-Seq) and further analyzed by means of informatics and experiments. A total of 912 Differentially Expressed Genes (DEGs) (FDR of q < 0.01), including 415 Cd-inducible and 497 Cd-repressed genes were identified. Based on the DEGs, 25 cadmium responsive Clusters of Orthologous Group (COG) and three types of cadmium-induced Gene Ontology (GO) including cellular components, molecular functions and biological processes were analyzed in details. Thereafter, 79 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways under cadmium exposure were assigned. Collectively, 108 redox balance related genes were extracted under cadmium exposure. Meanwhile, cadmium exposure lowered cellular Mitochondrial Membrane Potential (MMP) and increased Reactive Oxygen Species (ROS) levels significantly in the context of mitochondrial dysfunction. Furthermore, cadmium exposure increased cellular GSH levels and decreased GSSG levels and also lowered GSSG/GSH ratio of cells, which supports experimentally our claim that the redox balance is the primary mechanism for cadmium toxicity. The results present in this study may provide new strategies for cadmium detoxification and prevention or therapies of cadmium-associated diseases.