Wnt3a promotes melanin synthesis of mouse hair follicle melanocytes

Although the importance of Wnt3a in melanocyte development has been well recognized, the effect of Wnt3a in normal HF melanocytes has not been clearly elucidated yet. Thus, we sought to examine the presence and location of Wnt3a in HF during hair cycle. By using melanocyte-targeted Dct-LacZ transgenic mice, we found that Wnt3a signaling is activated in mouse HF melanocytes during anagen of hair cycle. To further explore the potential functions of Wnt3a in mouse melanocytes, we infected melan-a cells with AdWnt3a to serve as the production source of Wnt3a protein. We demonstrated that Wnt3a promoted melanogenesis through upregulation of MITF and its downstream genes, tyrosinase and TRP1, in melanocytes. In vivo, AdWnt3a rescued the effects of AdsimMITF on HF melanocytes and promoted melanin synthesis. Our results suggest that Wnt3a plays an important role in mouse HF melanocytes homeostasis.

► We examine the expression of Wnt3a in mouse hair follicles during hair cycle.
► We examine the expression of Wnt3a in mouse hair follicle melanocytes.
► We examine Wnt/β-catenin signaling in mouse hair follicle melanocytes.
► Wnt3a promotes the melanin synthesis of melanocytes though upregulation of MITF and its downstream genes, tyrosinase and TRP1.
► Wnt3a promotes the melanogenesis of hair follicle melanocytes in vivo.