Microarray-based Gene Expression Fingerprint in Leukocytes of Half-marathon Runners

Gene expression fingerprints are already a useful classification tool in tumor biology or drug application. PURPOSE: Similarly, gene expression profiling may provide information for the characterization and understanding of the immunological response to exercise. Microarray expression analysis affords the opportunity to find specific gene expression pattern (fingerprints) and to complete the list of involved genes. METHODS: An inflammation-centered cDNA microarray was used to screen mRNA expression in leukocytes of eight male athletes before (t0), immediately (t1) and 24h after (t2) a half marathon (HM). Differentially regulated gene expression was analyzed using a linear regression-based algorithm. Genes were clustered based upon similarity in gene expression changes with samples from t0 vs t1 and from t0 vs t2. The assumption for a gene to be clustered was that its regulation was identical in all eight athletes at the particular time. Selected genes were evaluated by quantitative Real Time PCR. RESULTS: Comparing t0 with t1, and t0 with t2, 36 and 21 genes respectively, were similarly regulated in all eight athletes. This pattern of identically changed genes can be viewed as a 'gene expression fingerprint' at the particular times post-exercise. Genes were allocated to functional groups such as signal transduction, cell type specific surface markers, cellular interaction and protection, apoptosis, and inflammatory processes. CONCLUSION: Microarray analysis is applicable for exercise-related gene expression profiling in human leukocytes. An exercise-related gene expression fingerprint may become helpful to characterize the immune response to different types of exercise or even to diagnose overtraining.