74 Skin responses to air pollution: keratinocyte toxicity and lipidomic remodelling in reconstructed skin

Abstract Airborne particulate matter (PM) pollution is increasingly recognized as a major threat to human health. The skin, as the body’s primary barrier, is directly exposed to air pollutants and may also be affected indirectly through systemic exposure. Growing evidence links air pollution to various skin disorders, including dermatitis, psoriasis, autoimmune diseases, and even cancers. Lipids play a key role in maintaining skin integrity and modulating cellular stress responses. In this study, we investigated the impact of air pollutants on skin health using an integrated in vitro approach combining keratinocyte cultures, reconstructed human skin models, high-throughput toxicity assays, and lipidomics. Air filters collected from rural and suburban sites during cold and warm seasons were extracted and analysed by GC-MS to quantify organic pollutants. Keratinocytes exposed for 72 h to extracts equivalent to 3 to 15 m³ air/mL showed significant cytotoxicity, regardless of origin. Cold-season samples induced stronger oxidative stress, whereas warm-season extracts triggered enhanced cytokine release (IL-6, IL-8). Reconstructed 30-d human skin models exposed for 3 to 6 d to rural air extracts exhibited marked lipidomic remodelling in both epidermis and dermis, particularly in ceramides and phosphatidylinositols. Interestingly, the poorly characterized lipids hemi-bis-monoacylglycerol phosphate (HBMP) and bis-monoacylglycerol phosphate (BMP) were significantly regulated upon exposure, suggesting a potential adaptive role in the skin’s response to environmental stress. Overall, our results demonstrate season-dependent effects of air pollution on skin health and reveal major changes in the skin lipid profile.