Peripheral Blood of Vitiligo Patients-Derived Exosomal MiR-21-5p Inhibits Melanocytes Melanogenesis via Targeting SATB1.

Background: Vitiligo is a common depigmentation disease characterized by progressive destruction and disappearance of epidermal melanocytes. Exosomes have been discovered to regulate the pigment status of melanocytes. We aimed to explore the role of exosomes from peripheral blood of vitiligo patients on melanogenesis. Methods: Human melanocytes cell line PIG1 was treated with exosomes from the healthy volunteers or exosomes from the vitiligo patients referred to the Department of Dermatology, Children's Hospital Affiliated to Zhengzhou University, China and transfected with miR-21-5p mimic or inhibitor. Exosome labeling assay was used to assess whether exosomes were absorbed by melanocytes. Melanin content and tyrosinase activity assays were performed to investigate melanogenesis in melanocytes. The levels of melanogenesis-related genes and proteins were detected by RT-qPCR and western blot assays. Dual-luciferase reporter assay was performed to confirm the relationship between miR-21-5p and special AT-rich sequence binding protein-1 (SATB1). Results: Exosomes from peripheral blood of vitiligo patients were transferred into melanocytes and suppressed melanin content, tyrosinase activity and melanogenesis-related genes and proteins levels. Besides, miR-21-5p was highly expressed in exosomes from peripheral blood of vitiligo patients. The results of the gain- and loss-of-function experiments demonstrated that miR-21-5p inhibited the melanogenesis of melanocytes. Furthermore, miR-21-5p inhibitor abolished the inhibitory role of exosomes from peripheral blood of vitiligo patients. Subsequently, miR-21-5p directly targeted SATB1 in melanocytes. Furthermore, overexpression of SATB1 reversed the inhibitory roles of miR-21-5p mimic on melanin content, tyrosinase activity, and melanogenesis-related protein expression. Conclusion: Peripheral blood of vitiligo patients-derived exosomal miR-21-5p inhibited melanocytes melanogenesis via targeting SATB1.