Endurance training changes the DNA methylation pattern in human skeletal muscle

Abstract

Long‐term endurance training induces many beneficial effects in human skeletal muscle. However, some people respond strongly while others barely improve. Training responsiveness is related to differential gene expression through incompletely understood mechanisms. We hypothesized that DNA methylation pattern changes with endurance training and that these changes could be related to training response.17 subjects (males and females) performed three months of supervised one‐legged knee extension endurance training. DNA from vastus lateralis muscle biopsies was used for an Illumina 450K chip. Training response was evaluated using one‐legged performance tests and enzyme activity assays.The Illumina data showed around 5000 sites that significantly changed in methylation level with training. Using methylation estimates for these sites, two responder groups were identified with different magnitude of change in citrate synthase activity. It was also possible to separate the males and females based on methylation level of these sites (excluding the sex chromosomes), a finding of great interest for the difference between male and female skeletal muscle.In conclusion, our results indicate that DNA methylation is affected by endurance training and could be one mechanism involved in the variability in response.