Oxidative stress-induced hypermethylation and low expression of ANXA2R: Novel insights into the dysfunction of melanocytes in vitiligo.

Background: Vitiligo is a skin disorder with melanocyte destruction caused by complex interplay between multiple genetic and environmental factors. Recent studies have suggested DNA methylation is involved in the melanocyte damage, but the underlying mechanism remains unknown.

Objective: To explore the abnormal DNA methylation patterns in vitiligo lesional and nonlesional skin, and the mechanism of DNA methylation involved in vitiligo pathogenesis.

Methods: Initially, the genome-wide aberrant DNA methylation profiles in lesional and nonlesional skin of vitiligo were detect via Illumina methylation EPIC 850k Beadchip. Subsequently, a comprehensive analysis was conduct to investigate the genomic characteristics of differentially methylated regions (DMRs). Furthermore, the effects of key aberrant methylated genes on cell apoptosis and function of both melanocytes and keratinocytes were further identified and validated by western bloting, ELISA, and immunofluorescence.

Results: Compared with nonlesional skins, we discovered 79 significantly differentially methylated CpG sites in vitiligo lesions. These DMRs were mainly located in the gene body and the TS1500 region. Annexin A2 receptor (ANXA2R), a crucial gene in cell apoptosis, was hypermethylated in vitiligo lesions. Furthermore, we showed that ANXA2R displayed hypermethylation and low expression levels in both keratinocytes and melanocytes of vitiligo patients, and the hypermethylated-triggered downregulation of ANXA2R under oxidative stress induced melanocyte apoptosis, and inhibited the secretion of stem cell factor (SCF) from keratinocytes thus impaired the survival of melanocytes.

Conclusions: Our study illustrates the DNA methylation modification in vitiligo, and further demonstrates the molecular mechanism of hypermethylated ANXA2R in the dysfunction of melanocytes under oxidative stress.