NB-UVB Induces Melanocytic Differentiation of Human Hair Follicle Neural Crest Stem Cells

ABSTRACT

Background@#Phototherapy is an important method to treatvitiligo. However, it is unclear how phototherapy affectsmelanocyte precursors and skin neural crest stem cells. @*Objective@#To investigate the underlying mechanisms of narrow-band ultraviolet B (NB-UVB) induced melanocyte lineagedifferentiated from human scalp-derived neural creststem cells (HS-NCSCs). @*Methods@#HS-NCSCs were expandedfrom scalp hair follicles. The c-Kit−/CD57− HS-NCSCs wereisolated by cell sorting. Different doses of NB-UVB wereused to irradiate these HS-NCSCs. Cell ultrastructure was examinedby transmission electron microscope. Melanocytemarker expression was analyzed by Quantitative RT-PCRand Western blot. Cell proliferation and migration were alsoevaluated. @*Results@#The c-Kit−/CD57− HS-NCSCs expressedembryonic NCSC biomarkers. NB-UVB at a dose of 100 mJof NB-UVB had little effect on the cell proliferation of differentiatedmelanocytes from c-Kit−/CD57− HS-NCSCs, while700 mJ inhibited cell proliferation significantly. The dendriticprocesses of differentiated melanocytes increased afterradiation. The tyrosinase and Melanocortin 1 receptor (Mc1R)expression of differentiated melanocytes increased after NB-UVB exposure. The effect of NB-UVB on tyrosinase expressionwas modulated by signaling inhibitors H89 andPD98059 as well as Mc1R level in the cells. The migrationability of differentiated melanocytes was enhanced under100 mJ exposure. @*Conclusion@#These data demonstrate thatNB-UVB facilitates melanocytic differentiation of the HSNCSCsand enhances migration of these cells. Mc1R andcAMP pathway play a critical role in NB-UVB induced melanocyticdifferentiation.