Hox in the Niche Controls Hair Heterogeneity

In the 2018 study by Yu et al., researchers investigated the role of Hoxc genes in creating regional differences in hair growth in mammals. They discovered that the expression of these genes in the dermal papilla varies along the body and influences these differences. The study, conducted on mice, showed that Hoxc gene expression is regulated by polycomb-dependent mechanisms and affects the Wnt/ß-catenin signaling pathway, crucial for hair follicle regeneration. A specific mutation in mice, the Koala (Koa) mutation, caused ear hair follicles to undergo multiple regenerative cycles, which was prevented by deleting the Hoxc gene cluster. The study concluded that Hox gene expression patterns not only establish the body plan during embryogenesis but also control stem cell activity in adult skin, which could help understand hair growth variations in mammals.