Wnt/β-catenin signaling pathway activates melanocyte stem cells in vitro and in vivo

Melanocyte stem cells (McSCs) are the origin of melanocytes that are periodically refreshed in skin and hair follicle. Previously, we reported that Wnt3a could promote melanogenesis, but the mechanism of McSCs activation remains unclear.We aimed to illustrate the roles of Wnt/ß-catenin signaling pathway during McSC activation.Adenovirus-mediated overexpression of Wnt3a and Wnt10b were used. In vitro experiments were performed on the immortalized melanocyte progenitor cell line iMC23, wheres in vivo experiments were performed in Dct-LacZ mice. Immunofluorescence and western blot were used to determine the protein expression.Wnt3a promotes the differentiation and melanogenesis of iMC23, by activating Wnt/β-catenin signaling pathway. Wnt3a induces hair follicle regeneration and McSC activation. Detailed analysis indicats that Wnt3a activated Wnt/β-catenin signaling pathway, thus promoting the differentiation of McSCs during this process. Wnt10b, another canonical Wnt signaling ligand, induces hair follicle regeneration and McSC activation as well.Wnt/β-catenin signaling pathway activates McSCs both in vitro and in vivo.