Skin Cells’ Protection Against UVA-Induced Changes in Co-Cultured Keratinocytes–Fibroblasts’ Proteome and Released Signaling Proteins by 3-O-Ethyl Ascorbic Acid

UVA radiation affects communication between the cells that create the human skin. To prevent UVA-induced damage, there is a constant search for compounds protecting all skin cells and homeostasis in their communication. Therefore, the aim of this study was to evaluate the effect of 24 h incubation with 3-O-ethyl ascorbic acid (EAA; 150 µM) on the intracellular proteome of co-cultured keratinocytes and fibroblasts after UVA irradiation (total dose 15 J/cm2), and on the protein profiles released into the medium by both cell types. A proteomic approach (nanoHPLC/QOrbiTrap) allowed the identification of proteins significantly modified by UVA and EAA. In keratinocytes, UVA radiation enhanced expression of pro-inflammatory and pro-proliferative/keratinizing proteins and decreased expression of antiapoptotic and antioxidant proteins, while in fibroblasts, UVA radiation induced expression mainly of pro-inflammatory proteins, simultaneously decreasing levels of proteins involved in the antioxidant response and growth factors. Increased pro-inflammatory protein and decreased growth factor levels were also observed in the medium. EAA restored the levels of these proteins compared to control cultures. The results of this study show that EAA may protect epidermal and dermal cells by reducing levels of pro-inflammatory proteins, increasing antioxidant system activity in skin keratinocytes and fibroblasts, and normalizing intercellular signaling.