EZH2 Regulates the Correlation between Skin Regeneration and the Duration of Mechanical Stretch.

It has been widely recognized that mechanical stretch can regulate the fate of stem cells (SCs). Previous research has shown that short-term mechanical stretch induces SC proliferation by activating the predominant transcription factor YAP, and YAP is a critical modulator in controlling epidermal proliferation. However, our study finds that after this phase, cell growth arrest appears, which is induced by long-term mechanical stretch. In the interfollicular epidermal SCs undergoing long-term mechanical stretch in vivo and in vitro, the level of H3K27me3 and its histone methyltransferase EZH2 are significantly elevated with suppressed expression of the target genes of YAP. EZH2 forms repressive H3K27me3 that suppresses gene transcription. Small-molecule inhibitor of EZH2 rescues significantly the cell growth arrest in interfollicular epidermal SCs induced by long-term mechanical stretch, thus promoting epidermal proliferation in vivo again. These findings reveal that there is an unexpected correlation between SC proliferation and the duration of mechanical stretch regulated by EZH2. This study of long-term mechanical stretch that induces cell growth arrest provides a strategy for clinical translation to promote skin regeneration.