Hair Follicle Dermal Stem Cells Regenerate the Dermal Sheath, Repopulate the Dermal Papilla, and Modulate Hair Type

The document details a study on the role of hair follicle dermal stem cells (hfDSCs) in hair follicle regeneration and hair type specification in mice. Researchers found that hfDSCs can regenerate the dermal sheath, repopulate the dermal papilla (DP), and are essential for normal hair growth and hair type determination. The study showed that hfDSCs are retained over multiple hair cycles, contribute to both the dermal sheath and DP, and are involved in the generation of different hair types. Ablation of these cells led to delayed hair growth and altered hair type, with a reduction in larger hair types and an increase in smaller zigzag hairs. The study involved various experiments, including tamoxifen-induced labeling of DS cells, skin grafts, and diphtheria toxin treatments to ablate hfDSCs. Quantitative data included the analysis of over 120 second telogen hair follicles from 3 mice, 600-800 anagen follicles per time point with 3 mice per time point, 60 anagen hair follicles quantified from 3 mice per group, and 240 follicles from 4 mice for fate analysis. The study concludes that hfDSCs play a crucial role in hair follicle regeneration and could be a target for hair growth restoration treatments.