An in silico analysis of genome-wide expression profiles of the effects of exhaustive exercise identifies heat shock proteins as the key players

Physical exercise induces important system disturbances in the human body in a dose-response manner. Meta-analyses of genome-wide expression studies (GWES) might contribute to identify gene expression patterns and to a better understanding of the molecular mechanisms behind the complexity of adaptations to exercise, under a systems biology approach. Here, we aimed to analyze available data for human GWES that have evaluated the effect of exhaustive exercise in peripheral blood mononuclear cells (PBMC) and white blood cells (WBC). Three primary datasets retrieved from the NCBI Gene Expression Omnibus were meta-analyzed using a random effects model in the NetworkAnalyst software. After identifying nine differentially expressed genes (DEGs), we performed functional enrichment analyses to extract relevant biological information. A protein-protein interactions network on DEGs was built to evaluate the associated regulatory pathways. We found that five upregulated genes were members of the heat shock protein family, one of the top stress-response groups of genes. The enrichment analysis revealed key roles of the DEGs on the cellular adaptations to exercise-induced stress (i.e., temperature stimulus, topologically-incorrect and unfolded proteins). Our comparison analysis of DEG signatures found in blood cells with the expression pattern on muscle skeletal tissue showed some common genes. Thus, novel DEGs that might serve as hormetic mediators to exercise-induced adaptations were identified. Further experimental research is needed to validate these findings.