Vibrissa Hair Bulge Houses Two Populations of Skin Epithelial Stem Cells Distinct by Their Keratin Profile

The study identified two distinct populations of epithelial stem cells in the bulge region of rodent vibrissa hair follicles, characterized by their keratin profiles. Bb cells, located in the outermost basal layer, expressed K5, K15, K17, and K19, while Bs1 cells, found in the suprabasal layers, expressed K5/K17. Both cell types lacked K14 expression. The presence of these cells, particularly the role of K5/K17 filaments, was crucial for the long-term survival of engineered tissues, highlighting the heterogeneity within hair follicle stem cells and their potential in skin tissue engineering.