Dermis-Hair Follicle Communication: Extracellular Microvesicles Signaling for Hair Regeneration

The study explored how extracellular microvesicles (EVs) from dermal fibroblasts influence hair follicle regeneration. Dermal fibroblasts were treated with PDGF-AA and bFGF, leading to the secretion of EVs that promoted hair growth ex vivo. These EVs activated the NDP gene in dermal papilla cells, causing them to secrete norrin, which then triggered the ß-catenin pathway in follicular keratinocytes, stimulating hair growth. The research also discovered that the norrin receptor Frizzled4, usually scarce in human hair follicle keratinocytes, was present on EVs from dermal fibroblasts, implying that these EVs supply Frizzled4 to enhance norrin's effects. The study concluded that EVs from dermal fibroblasts are potent activators of dermal papilla cells and highlighted norrin as a key factor in hair follicle regeneration.