Protein S-glutathionylation correlates to selective stress gene expression and cytoprotection

During situations of oxidative stress phenotypic adaptation to altered redox state is achieved by changes in expression of selected genes. The mechanisms regulating this may involve reversible S-glutathionylation of cellular proteins. In this study we compared and contrasted changes in gene expression patterns in human type II lung epithelial A549 cells and human endothelial ECV304 cells in correlation to glutathione oxidation and the formation of glutathione-protein mixed disulphides, after exposure to subtoxic levels of hydrogen peroxide, formed in the medium by addition of glucose oxidase, or the thiol oxidant diamide. Both the number of specific mRNAs and their levels of induction were grossly correlated to the degree of S-glutathionylation of cellular protein. Thus, diamide induced the expression of a variety of protein and DNA chaperones and transcriptional regulators, particularly in ECV304 cells. On the other hand, the peroxide failed to induce many of these species, in association with only minimal disturbances to glutathione homeostasis. The induction of the chaperone responses at the level of mRNA was clearly shown to translate into a more resistant morphological phenotype in response to both heat shock and oxidative stress induced by the DNA-damaging pro-oxidant potassium bromate.