Background: Extrinsic aging results from environmental stressors such as UVR or pollutants. While the effects of single pollutants are better understood, those of their combination remain poorly scrutinized. Objective: Building on a study showing downregulation of several processes upon co-exposure to B[a]P and UVA, we investigated changes induced by epigenetic marks. Materials and Methods: Human primary fibroblasts and HaCaT cells were exposed to B[a]P and UVA. After 24 hours, exposed and unexposed cells were compared to assess DNA methylation. Focusing on HaCaT, multiplex assays enabled quantifying histone H3 modifications and evaluating four splicing factors (SRSF1, SRSF3, SFPQ, and SF3B1) by immunohistochemical labeling. The expression of keratinocyte-/fibroblast-relevant genes was assessed by RT-qPCR. Finally, the impact of an Arundo donax L. extract added 24 hours before B[a]P-UVA co-exposure was analyzed. Results: Exposure to B[a]P-UVA raised DNA methylation (HaCaT: ×3.6, fibroblasts: ×1.9), an increase prevented by the extract. In HaCaT cells, B[a]P-UVA increases the frequency of S10P (+38%). When exposure was preceded by extract treatment, the frequency of several methylations was impacted. B[a]P-UVA only induced the expression of SRSF1 and SFPQ in HaCaT (+46% and +34%). Treatment with the extract abolished this effect. Co-exposure increases the expression of inflammation-related genes (IL-1α, IL-1β) in HaCaT cells and decreases those of AQP3, KRT15, and SOD2. The extract has little effect on these changes. In primary fibroblasts, exposure to B[a]P-UVA lowered the expression of LOXL2, LUM, and TGFBR2 (−38%, −59%, and −51%, respectively), and the extract did not affect these modifications. Conclusion: Within 24 hours, a single B[a]P-UVA co-exposure changes epigenetic marks of skin cells but has only mild effects on gene expression. An Arundo donax L. extract can prevent part of the epigenetic marks’ changes and could stimulate the expression of some genes in primary fibroblasts.
Marie M. DorrMagali Favre-MercuretKatell ViéRichard Fitoussi
When a steel plate produced by a steel plant leaves the factory,its upper surface should be marked with the specification,variety,batch number,and other identifying information,and its side should be marked with a side marking.The side marking contains the plate number,specification,batch number,and other information,which are convenient for customers to accurately identify relevant information after stacking.However,because of the influence of weather,environment,and other factors,the side marking becomes unidentifiable when the steel plate is corroded,affecting the customer’s loading,unloading,and other operations.The development and application of side anticorrosion devices and cleaning of finished heavy steel plates with antirust agents will solve the problem of unrecognizable side marking due to corrosion.
