Hair Cycle Control by Vanilloid Receptor-1 (TRPV1): Evidence from TRPV1 Knockout Mice

The study explored the role of the vanilloid receptor-1 (TRPV1) in hair cycle regulation using TRPV1 knockout mice. TRPV1 was expressed in specific regions of the epidermis and hair follicles in both humans and mice, with expression levels varying throughout the hair cycle. Notably, TRPV1 knockout mice showed a delay in transitioning from the final stages of hair follicle morphogenesis to cycling, suggesting that TRPV1 signaling is involved in modulating these transitions. The absence of TRPV1 was linked to delayed spontaneous involution of hair follicles, indicating that TRPV1 may inhibit hair follicle keratinocyte proliferation. This research suggested that TRPV1 had broader roles in skin and hair biology than previously recognized.