Differential Sensitivity of Epidermal Cell Subpopulations to Beta-Catenin-Induced Ectopic Hair Follicle Formation

The study investigated the ability of different epidermal cell populations to form ectopic hair follicles in response to β-catenin activation in adult mouse epidermis. By using a 4-hydroxy-tamoxifen inducible, stabilized beta-catenin transgene under two promoters, researchers found that the interfollicular epidermis (IFE) did not form ectopic follicles, indicating its autonomy. Activation in the hair follicle bulge led to proliferation and anagen entry but no ectopic follicles, while activation in the sebaceous gland base resulted in the formation of ectopic follicles, converting sebaceous glands into hair follicles. The study concluded that the bulge is a non-permissive niche, whereas the sebaceous gland is a permissive niche for Wnt-induced hair follicle differentiation.