Elevated H3K27ac in aged skeletal muscle tissue drives a fibrogenic conversion of muscle satellite cells

A variety of epigenetic alterations impairs functions of cells and tissues during aging, but it is not known if epigenetic alterations are associated with aging muscle. Here, we examined the changes of a panel of histone marks and found H3K27ac (an active enhancer mark) is markedly increased during aging in human skeletal muscle tissues. Our integrated analysis showed that enhancer activation during muscle aging is associated with the up-regulation of extracelluar matrix (ECM) genes, which may result in stiffness of the niche environment of satellite cells (SCs). An age-related fibrogenic conversion of geriatric SCs was observed through differential gene expression analysis. In mice, treatment of aging muscles with JQ1, an inhibitor of enhancer activation reverted the ECM up-regulation and fibrogenic conversion of SCs, suggesting that ECM increase in aging muscle is indeed a result of enhancer activation. The study here not only uncovered a novel aspect of muscle aging that is associated with enhancer remodeling but also highlighted JQ1 as a potential treatment approach for restoring SC function in aging muscle. Overall design: 3 ChIP-seq experiments were performed