Aerobic training in urban environment: blood gene expression profiling

Abstract

Background Physical activity is a recommended life-style activity to promote health, while particulate matter (PM) exposure induces adverse health effects. The aim was to investigate the impact of PM exposure during aerobic training on the blood gene expression profile. Methods Healthy, untrained subjects participated in a 12-week aerobic training program (3 sessions/wk), one group (n=15) in an urban location, another group (n=9) in a rural location. Ultrafine particles (UFP) were measured at the training locations during the training sessions. Fitness levels (cooper-test) and whole-genome blood gene expression profiles in blood were determined before and after the program. The up or downregulation of the genes was called significant in case of a multiplicity corrected p-value<0.05 and an effect size in terms of absolute fold change > 1.5. Results UFP concentrations were higher (p = 0.003) in the urban location (7240 particles/cc) compared to the rural location (5621 particles/cc). Fitness level improved (p < 0.0001) equally in both groups (p = 0.16).The expression of 816 genes was altered in the urban group (399 upregulated, 417 downregulated) and 709 genes showed differential expression (665 upregulated, 44 downregulated) in the rural group. The expression of 55 genes of the 254 genes that were altered in both groups were linked to stress response by Gene Ontology. One third of the differentially expressed genes was in common between the groups. The statistical analysis revealed an interaction effect for 246 genes. Thirty nine genes were upregulated and 207 genes were downregulated when the urban group was compared to the rural group. Gene Ontology analysis indicated a significant enrichment for the biological term cell death. No specific terms of genes were discovered that can be associated with immune or inflammatory processes. Conclusions Our study revealed a differential blood gene expression profile with aerobic training in an urban location compared to aerobic training in a rural location.