Hedgehog Stimulates Hair Follicle Neogenesis by Creating Inductive Dermis During Murine Skin Wound Healing

In 2019, a study discovered that activating the Sonic hedgehog (Shh) pathway can encourage hair follicle regeneration during wound healing in mice. The Shh pathway forms a regenerative dermal niche, known as dermal papilla, which is essential for new hair follicle formation. The research showed that either increasing Shh in the skin or activating the Smoothened dermal pathway led to significant hair follicle formation in wounds that would typically scar. The study also indicated that while long-term Wnt activation is linked with fibrosis, triggering the Shh signal in Wnt active cells encourages the dermal papilla fate in scarring wounds. This implies that scarring and regeneration mechanisms are closely related, and wound repair can be redirected to enhance regeneration after injury by altering a crucial dermal signal.