Embryonic-Like Regenerative Phenomenon: Wound-Induced Hair Follicle Neogenesis

The document from September 1, 2018, reviews the process of wound-induced hair follicle neogenesis (WIHN), where new hair follicles form in the center of a full-thickness wound in adult mice, similar to embryonic hair development. It was found that a sufficiently large wound is required for WIHN to occur, with new follicles forming between days 14-21 post-wound, and the number of new follicles decreases with the age of the mice. The cellular origins of WIHN are not from hair stem cells in the bulge but may involve reprogramming of epidermal and upper follicle cells. Key molecular mechanisms include the Wnt/ß-catenin pathway, with Wnt ligands from epidermal cells activating ß-catenin in the dermis, and FGF9, secreted by γδ T cells, also playing a regulatory role. The findings suggest that understanding WIHN could lead to new treatments for hair loss and contribute to regenerative medicine and stem cell research.