Inhibition of BMP Signaling Affects Growth and Differentiation in the Anagen Hair Follicle

The study investigated the role of Bmp signaling in hair follicle development during the anagen phase using transgenic mice expressing the Bmp inhibitor, Noggin. It was found that inhibiting Bmp signaling severely impaired hair shaft differentiation, as evidenced by reduced expression of hair keratins and transcription factors such as Foxn1 and Hoxc13. Proliferating cells, typically confined to the hair matrix, were observed in the precortex and hair shaft region, indicating that Bmp signaling normally restricted proliferation to specific regions. The study suggested that Bmp signaling was crucial for inducing the genetic program necessary for hair shaft differentiation and played a positive role in postnatal hair development by inducing differentiation and restricting proliferation.