The skin, the largest organ in humans, is exposed to major sources of outdoor air pollution, such as fine particulate matter with a diameter ≤ 2.5 µm (PM2.5). Diphlorethohydroxycarmalol (DPHC), a marine-based compound, possesses multiple activities including antioxidant effects. In the present study, we evaluated the protective effect of DPHC on PM2.5-induced skin cell damage and elucidated the underlying mechanisms in vitro and in vivo. The results showed that DPHC blocked PM2.5-induced reactive oxygen species generation in human keratinocytes. In addition, DPHC protected cells against PM2.5-induced DNA damage, endoplasmic reticulum stress, and autophagy. HR-1 hairless mice exposed to PM2.5 showed lipid peroxidation, protein carbonylation, and increased epidermal height, which were inhibited by DPHC. Moreover, PM2.5 induced apoptosis and mitogen-activated protein kinase (MAPK) protein expression; however, these changes were attenuated by DPHC 5. MAPK inhibitors were used to elucidate the molecular mechanisms underlying these actions, and the results demonstrated that MAPK signaling pathway may play a key role in PM2.5-induced skin damage.
Keywords: MAPK; PM2.5; diphlorethohydroxycarmalol; human keratinocytes; skin cell damage.