Abstract
Members of the TGF-β/BMP family such as BMP-4 and TGFβ-1,2 are involved in the control of hair follicle morphogenesis. This prompted us to explore the role of TGF-β/BMP family member activin and its antagonist follistatin in pelage hair follicle development. Here, we show that during hair follicle development, follistatin mRNA is prominently expressed by hair matrix and outer root sheath keratinocytes as well as by interfollicular epidermis, whereas activin βA-mRNA is mainly expressed in dermal papilla cells. Compared to age-matched wild-type controls, both follistatin knockout mice and activin βA transgenic mice show a significant retardation of hair follicle morphogenesis. Treatment of wild-type, embryonic skin explants with follistatin protein stimulates hair follicle development. This effect is inhibited by the addition of recombinant activinA protein. These observations suggest that follistatin and activin interaction plays an important role both in hair follicle development and may be exploited as a regenerative treatment for patients with alopecia.
