Characterization of cyclobutane pyrimidine dimer-dependent modulation of gene expression in human keratinocytes following UVB exposure

To address CPD-dependent UVB activities, a model system was established in which transfection of keratinocytes with pseudouridine-modified mRNA (Ψ-mRNA) encoding CPD-photolyase resulted in 90% reduction of CPDs within 6 and 24 hours after UVB exposure. Microarray analysis of this model system demonstrated that more than 50 % of the gene expression altered by UVB were changed in a CPD-dependent manner. The expression of most of the CPD-dependent genes was changed at 6 h after UVB as compared to 24 h likely due to the higher CPD levels. Nine genes (ATF3, CCNE1, CDKN2B, EGR1, ID2, PTGS2, RUNX1, SNAI1, SNAI2) regulated by CPDs were selected for further investigation (qPCR, Western blot) based on the microarray data. Gene expression modulated by UVB irradiation in HaCaT keratinocytes was measured at 6 and 24 hours after the exposure to dose of 20 mJ/cm2 UVB. Three independent experiments were performed at each time (6 or 24 hours) using different passages for each experiment.