IL‐17 induces cellular stress microenvironment of melanocytes to promote autophagic cell apoptosis in vitiligo

Vitiligo is a depigmentary disorder that develops as a result of the progressive disappearance of epidermal melanocytes. Stress can precipitate or exacerbate a skin disease through psychosomatic mechanisms. Stress exposure induces vitiligo-like symptoms in mice, as cellular damage to melanocytes causes synthetic pigment loss. Stress also increases IL-17, IL-1β, and antimelanocyte IgG in model mouse serum. Up-regulation of the IL-1β transcript in patients suggests its possible role in autoimmune pathogenesis of vitiligo. We demonstrate that IL-17 promoted IL-1β secretion from keratinocytes. Mitochondrial dysfunction, which can induce the excessive production of reactive oxygen species (ROS), is emerging as a mechanism that underlies various inflammatory and autoimmune diseases. In this study, we demonstrate that IL-17 inhibits melanogenesis of zebrafish, normal human epidermal melanocytes, and B16F10 cells. IL-17 increased mitochondrial dysfunction and ROS accumulation, which was related to autophagy induction. Autophagy is needed for autophagic apoptosis of B16F10 cells induced by IL-17. To inhibit ROS generation, B16F10 cells were pretreated with N-acetyl-l-cysteine (NAC), which inhibited autophagy. 3-Methyladenine (3-MA) also had an inhibiting effect on autophagy. NAC or 3-MA pretreatments inhibited IL-17-mediated cell apoptosis. In summary, IL-17 induces the cellular stress microenvironment in melanocytes to promote autophagic cell apoptosis in vitiligo.-Zhou, J., An, X., Dong, J., Wang, Y., Zhong, H., Duan, L., Ling, J., Ping, F., Shang, J. IL-17 induces cellular stress microenvironment of melanocytes to promote autophagic cell apoptosis in vitiligo.