The Identification of Bipotent Dermal Stem Cells and the Role of Anti-Inflammatory Macrophages During Hair Follicle Regeneration

The study identified bipotent dermal stem cells (hfDSCs) within the adult hair follicle mesenchyme, which exhibited self-renewal and were crucial for hair regrowth and type specification. Ablation of these cells hindered hair regeneration, highlighting their potential in restoring hair growth after injury, disease, and aging. Additionally, the research explored the role of anti-inflammatory macrophages in hair follicle regeneration, particularly through wound-induced hair growth (WIHG). It was found that specific macrophages (CD11b+ CX3CR1hi CCR2+ Ly6Clo) increased TGF1 concentrations, activating epithelial stem/progenitors and stimulating hair follicle regeneration. The absence of CX3CR1, but not CCR2, abolished WIHG, revealing a novel mechanism by which macrophages influence hair follicle stem cells during tissue regeneration.