MicroRNA-155 is Dysregulated in the Skin of Patients with Vitiligo and Inhibits Melanogenesis-associated Genes in Melanocytes and Keratinocytes

Little is known about the functions of microRNAs (miRNAs) in skin pigmentation disorders. The aim of this study was to investigate the expression and potential role of miRNAs in vitiligo. Of 12 studied miRNAs with proven functions in cell proliferation, differentiation, immune responses and melanogenesis, miR-99b, miR-125b, miR-155 and miR-199a-3p were found to be increased and miR-145 was found to be decreased in the skin of patients with vitiligo. Combined pathway and target analysis revealed melanogenesis-associated targets for miR-99b, miR-125b, miR-155 and miR-199a-3p. In situ hybridization analysis demonstrated increased expression of miR-155 in the epidermis of patients with vitiligo. Correspondingly, miR-155 was induced by vitiligo-associated cytokines in human primary melanocytes and keratinocytes. When overexpressed, miR-155 inhibited the expression of melanogenesis-associated genes and altered interferon-regulated genes in melanocytes and keratinocytes. In conclusion, this study demonstrates that the expression of miRNAs is dysregulated in the skin of patients with vitiligo and suggests that miR-155 contributes to the pathogenesis of vitiligo.