GSE132220
Hairless regulates heterochromatin maintenance and muscle stem cell function as a histone demethylase antagonist (ChIPseq, ATACseq)
Skeletal muscle possesses remarkable regenerative ability owing to the resident muscle stem cells (MuSCs). A prominent feature of quiescent MuSCs is a high content of heterochromatin. However, little is known about the mechanisms by which heterochromatin is maintained in MuSCs. We found that the mammalian Hairless (Hr) gene is expressed in quiescent MuSCs. Using a mouse model in which Hr can be specifically ablated in MuSCs, we demonstrate that Hr expression is critical for MuSC function and muscle regeneration. We show that Hr is a histone demethylase antagonist that preserves Histone 3 Lysine 9 trimethylation (H3K9me3) and maintains heterochromatin structure. Loss of Hr results in reduced H3K9me3 levels, reduced heterochromatin, increased susceptibility of MuSCs to genotoxic stress, and the accumulation of DNA damage. Our study not only elucidates the molecular mechanism by which Hr regulates histone demethylases, but also demonstrates the importance of heterochromatin maintenance in stem cell function. Overall design: Skeletal muscle stem cells (MuSCs) were isolated from conditional Hairless knockout and control mice by FACS and processed for ChIP-seq using H3K9me3-specific antibodies.