Gly-Pro protects normal human dermal fibroblasts from UVA-induced damages via MAPK-NF-κB signaling pathway

Photoaging is characterized by skin dysfunction and wrinkle formation predominantly caused by chronic exposure to ultraviolet (UV) irradiation. Collagen peptides are well-recognized as nutritional supplements for enhancing skin health. Gly-Pro, a dipeptide found in collagen as a major repetitive sequence, is considered a prospect collagen peptide derivative that displays anti-photoaging potential. Herein, we evaluated the photoprotective effects of Gly-Pro in normal human dermal fibroblasts (NHDFs). Pretreatment by Gly-Pro at a concentration of 0.1 μM inhibited UVA-driven generation of reactive oxygen species (ROS) in NHDFs and attenuated UVA-induced changes in mRNA expression and activation of proteins of the MAPK-NF-κB signaling pathway. Meanwhile, Pro-Gly and cyclo(-Gly-Pro), two dipeptides that are structurally similar to Gly-Pro, depicted less anti-photoaging effects against UVA irradiation. Collectively, our data suggests that Gly-Pro has potential as a novel ingredient in nutricosmetic products for skincare and anti-photoaging.