Injury Modifies the Fate of Hair Follicle Dermal Stem Cell Progeny in a Hair Cycle-Dependent Manner

The study investigated how injury affects the behavior of hair follicle dermal stem cells (hfDSCs) and their progeny in relation to wound-induced hair growth (WIHG) and hair cycle stages. Using αSMACreERT2 :ROSAYFP mice treated with tamoxifen to label hfDSCs, researchers performed full-thickness skin excisions at different hair cycle stages and analyzed the skin at the subsequent anagen phase. They found that injury increased the recruitment of hfDSC progeny into the dermal papilla (DP) compared to natural hair cycle progression, with this recruitment bias occurring only when the wound was induced during specific hair cycle stages. Thus, injury modified the fate of hfDSC progeny, favoring their incorporation into the DP, and this response was dependent on the hair cycle stage.