Linking Morphogen and Chromatin in the Hair Follicle

In the 2013 study by Xiong et al., the chromatin remodeler Brg1 was found to be essential for the maintenance of hair follicle stem cells and epidermal repair. The study revealed that Brg1 interacts with the Sonic Hedgehog (Shh) signaling pathway to create a positive feedback loop that promotes hair follicle growth. The absence of Brg1 led to a significant decrease in hair follicle maintenance, loss of stem cell markers, and hair loss. Furthermore, Brg1 null hair follicles failed to respond to depilation or wound-induced repair. The research also showed that Brg1 regulates Shh expression by activating its promoter, while Shh signaling increases Brg1 expression in hair follicle stem cells, indicating a crucial reciprocal relationship for hair follicle maintenance and epidermal repair.