Progress on hair follicle stem cells

The document discussed the role of hair follicle stem cells in hair follicle morphogenesis and cycling, highlighting their location in the bulge area of the outer root sheath. These stem cells were characterized by slow cycling, multipotential differentiation, and self-renewal abilities. The surrounding microenvironment, particularly dermal papilla cells, played a crucial role in their proliferation and differentiation. Two main hypotheses, the bulge activation hypothesis and the stem cell migration hypothesis, were proposed to explain stem cell involvement in hair follicle morphogenesis and cycling. Key signaling pathways, including Wnt, BMP, and Shh, were identified as critical in these processes, with β catenin and LEF1/TCF being essential for converting stem cells to matrix cells and initiating hair follicle keratin gene expression.