Differences in rutin effect on membrane phospholipids in skin fibroblasts irradiated with UVA and UVB

Chronic exposure of the skin to solar UV radiation induces a number of biological alterations, including a redox imbalance; therefore, there is a constant need for protective compounds, particularly natural antioxidants. The aim of this study was to determine the effect of rutin on interactions between membrane phospholipid and antioxidant proteins expression in UVA or UVB irradiated fibroblasts. Following exposure to UVA and UVB irradiation cells were incubated with rutin 12h before and/or up to 24h after irradiation, and the structural and metabolic changes were examined at selected time intervals. Rutin penetration through the fibroblast phospholipid bilayer was aided by UVA-induced bilitranslocase activity, while lipidomic analysis revealed that following UVB-irradiation rutin transport into cell is enhanced by changes in membrane permeability resulting from UVB-induced lipid peroxidation. Moreover, rutin partially prevented UVA/B-induced increase in phosphatidylethanolamine and phosphatidylcholine and decrease in sphingomyelin, as well as their membrane localization. However, the inhibition of phospholipase A2 activity and increase in ROS level resulted in protection against the reduction of phospholipids/free arachidonic and linoleic acids and the increase in the level of the lipid peroxidation product 4-HNE, which demonstrates the antioxidant proteins regulatory properties. The antioxidant activity of rutin, effectively prevented the enhanced ROS generation as well as antioxidant system destruction. Proteome analysis show that rutin treatment more strongly protects against UVA-induced rather than UVB-induced increases in the total expression of proteins involved in antioxidant response (such as SOD, TrxR, and Prxs 1/2). However, in the case of UVB-irradiated cells, rutin additionally enhances the levels of disulfide-isomerase – an enzyme that is responsible for the formation and breakage of disulfide bonds, what in the case of Nrf2/ARE pathway has significant meaning in the Nrf2 transcriptional activity level and leads to the synthesis of cytoprotective proteins. In conclusion, UVA and UVB radiation in partially different ways affect rutin interactions with the fibroblast biomembrane lipids as well as antioxidant proteins. Rutin membrane penetration is promoted by UVA-induced bilitranslocase activity, while UVB irradiation enhanced membrane permeability to facilitate the interaction of rutin with phospholipids. Moreover, rutin particularly influences UVA-induced antioxidant proteins expression and UVB-induced transcription signaling.