Deficiency of Crif1 in Hair Follicle Stem Cells Retards Hair Growth Cycle in Adult Mice

The study investigated the role of Crif1, a mitochondrial protein, in hair follicle stem cells (HFSCs) and its impact on the hair growth cycle in adult mice. Researchers created two types of inducible conditional knockout (icKO) mice, one with epidermal specific Crif1 deficiency (Crif1 K14icKO) and another with HFSC specific deficiency (Crif1 K15icKO). Both types of Crif1-deficient mice exhibited a significant retardation in the hair growth cycle compared to wild type mice, particularly in a depilation-induced anagen model. However, the HFSC populations were maintained despite the Crif1 deficiency. These findings indicate that while mitochondrial function in HFSCs is crucial for the progression of the hair growth cycle, it is not necessary for the maintenance of the HFSCs themselves.