Msi2 Maintains Quiescent State of Hair Follicle Stem Cells by Directly Repressing the Hedgehog Signaling Pathway

In a 2017 study, researchers discovered that the Msi2 protein is crucial in maintaining the inactive state of hair follicle stem cells by directly repressing the Hedgehog (Hh) signaling pathway, a key regulator of these cells. When Msi2 was deleted, there was an increase in hair follicle stem cell activation, leading to premature hair growth. The study also found that overexpression of Msi2 resulted in fewer new hair follicles forming, indicating that Msi2 suppresses hair follicle creation. Msi2 was found to directly target and repress the gene Shh, a key component of the Hh pathway, regulating hair regrowth after depilation. These findings suggest that Msi2 plays a significant role in maintaining hair follicle stem cell inactivity during the transition from resting to active growth phase, thus suppressing hair regeneration.