Changes in the transcriptome of circulating neutrophils and skeletal muscle in response to endurance exercise

Analysis of the changes in the transcriptome of circulating neutrophils and skeletal muscle from standardized resting conditions (baseline; pre-EXTRI) to 3, 48 and 96 hours after an experimental exercise trial (EXTRI; 1 hour of cycling followed by 1 hours of running) in 8 healthy, endurance-trained, male subjects. It was hypothesized that the time-course dependent transcriptomic changes would reflect the molecular and signalling mechanisms by which neutrophils regulate and counter-regulate inflammation, and by which skeletal muscle responds, regenerates, and phenotypically adapts to intense, prolonged exercise involving muscle damage. Results provide an important insight in the signalling pathways underlying the transcriptional activation and priming of circulatory neutrophils in response to physiological stress, in particular muscle-derived damage-associated molecular patterns. Furthermore, the study provides novel data on the skeletal muscle transcriptome beyond 48 hours after strenuous endurance exercise, and indicates important muscular remodelling processes at 96 hours post-EXTRI. Blood and muscle samples were taken under standardized conditions at baseline (pre-EXTRI), and 3, 48 and 96 hours post-EXTRI. Total mRNA was extracted from isolated neutrophils, and from skeletal muscle tissue.