UVB-Induced Facultative Pigmentation Is Associated With Distinct DNA Methylation Changes

This study investigates the differences in UVB-induced DNA methylation and melanogenesis between tan-capable (SPT-II) and non-tan (SPT-I) skin. Using ex vivo human skin exposed to UVB radiation, researchers found that SPT-II skin developed visible facultative pigmentation and showed fewer DNA damage markers compared to SPT-I skin. Whole-genome bisulfite sequencing revealed distinct methylation changes in pigmentation genes, with GNAS showing persistent alterations in both skin types. SPT-II skin exhibited coordinated hypomethylation in genes like GNAS, USP9X, and FANCA, potentially linked to melanogenic activation, while SPT-I skin showed variable methylation patterns. The study identifies GNAS as a UVB-responsive gene, suggesting its role in tanning capacity and highlighting potential targets for future research on photoaging and pigmentation disorders.