CCAAT/enhancer ‐binding protein beta promotes muscle stem cell quiescence through regulation of quiescence‐associated genes

CCAAT/enhancer ‐binding protein beta (C/EBPβ) promotes muscle satellite cell quiescence. (A) In resting muscle, satellite cells are quiescent and express both PAX7 and C/EBPβ. C/EBPβ promotes the expression of several quiescence‐associated genes includingCav1. (B) Muscle injury drives activation and proliferation of precursors with a concomitant reduction in C/EBP β expression. (C) Low C/EBPβ expression promotes differentiation and muscle repair. (D) Cells that escape differentiation, self‐renew and return to quiescence are C/EBPβ+. AbstractRegeneration of skeletal muscle depends on resident muscle stem cells called satellite cells that in healthy, uninjured muscle remain quiescent (noncycling). After activation and expansion of satellite cells postinjury, satellite cell numbers return to uninjured levels and return to mitotic quiescence. Here, we show that the transcription factor CCAAT/enhancer ‐binding protein beta (C/EBPβ) is required to maintain quiescence of satellite cells in uninjured muscle. We show that C/EBPβ is expressed in quiescent satellite cells in vivo and upregulated in noncycling myoblasts in vitro. Loss of C/EBPβ in satellite cells promotes their premature exit from quiescence resulting in spontaneous activation and differentiation of the stem cell pool. Forced expression of C/EBPβ in myoblasts inhibits proliferation by upregulation of 28 quiescence‐associated genes. Furthermore, we find that caveolin‐1 is a direct transcriptional tar...
Source: Stem Cells - Category: Stem Cells Authors: Tags: TISSUE ‐SPECIFIC STEM CELLS Source Type: research