There And Back Again: Hair Follicle Stem Cell Dynamics

The study explored the dynamics of hair follicle (HF) stem cells, revealing that stem cell descendants can return to the bulge niche and contribute to its function. Using murine models, the researchers demonstrated that slow-cycling stem cell derivatives persist outside the niche during hair growth and serve as functional stem cells in subsequent cycles. Rapidly cycling outer root sheath (ORS) cells also survived catagen and returned to the bulge, maintaining stem cell quiescence. The study highlighted the heterogeneity within the bulge, showing that CD34+ cells are capable of follicle regeneration and wound repair, while CD34−K6+ cells contribute to the niche environment. These findings suggested that HF stemness is an intrinsic characteristic of the cells, influenced by their exposure to various signaling environments along the follicle.