Sunscreen cosmetic protects human fibroblast cultures against UVA-induced autophagy
Author: Samara Eberlin
Published at: October 08, 2014
23rd EADV Congress (European Academy of Dermatology and Venereology); Amsterdam, October 8-12, 2014.
Clerici SP, Eberlin S, Polettini AJ, Pereira AFC, Dolis E, Cascais LC, Lage R, Torloni LBO, Costa A.
Autophagy is an evolutionarily conserved process in eukaryotic cells for the degradation and recycling of long-lived proteins and cytoplasmic organelles. Autophagy has a survival and cytoprotective function and can be activated by various stress stimuli, including nutrient starvation and DNA damage triggered by chemical substances, reactive oxygen species, and ionizing radiation. Ultraviolet (UV) radiation induces DNA damage, autophagy, and apoptosis upon prolonged exposure. A physiological event like aging or deleterious events like UV radiation induces oxidation and aggregate formation of oxidized proteins. Lipofuscin is one of these aggregates and is considered a biological marker of senescence. In this study, we evaluated the protective effect of a sunscreen cosmetic product (SC) against UVA-induced autophagy using Sudan Black B (SBB), a specific stain for lipofuscin, with an in vitro model of human fibroblasts. UVA-induced autophagy can be measured by the presence of visible perinuclear and cytoplasmic aggregates of lipofuscin in HFF-1 cells stained with SBB, appearing as dark blue-black granules, compared to the control group. Concomitant incubation of HFF-1 with SC promoted a clear reduction in lipofuscin accumulation, making the cells acquire the same characteristics as the control group. Considering the reduced lipofuscin formation in fibroblast cultures treated with SC, we suggest a possible effect of this product on the optimization of the protein recycling process, culminating in a reduction in the accumulation of oxidized proteins. Studies are in progress in our laboratory to investigate additional mechanisms underlying the autophagy process, as well as the synthesis of proteasome and MAP1LC3.