We tested whether novel CYP11A1-derived vitamin D3- and lumisterol-hydroxyderivatives, including 1,25(OH)2D3, 20(OH)D3, 1,20(OH)2D3, 20,23(OH)2D3, 1,20,23(OH)3D3, lumisterol, 20(OH)L3, 22(OH)L3, 20,22(OH)2L3, and 24(OH)L3, can protect against UVB-induced damage in human epidermal keratinocytes. Cells were treated with above compounds for 24 h, then subjected to UVB irradiation at UVB doses of 25, 50, 75, or 200 mJ/cm2, and then examined for oxidant formation, proliferation, DNA damage, and the expression of genes at the mRNA and protein levels. Oxidant formation and proliferation were determined by the DCFA-DA and MTS assays, respectively. DNA damage was assessed using the comet assay. Expression of antioxidative genes was evaluated by real-time RT-PCR analysis. Nuclear expression of CPD, phospho-p53, and Nrf2 as well as its target proteins including HO-1, CAT, and MnSOD, were assayed by immunofluorescence and western blotting. Treatment of cells with the above compounds at concentrations of 1 or 100 nM showed a dose-dependent reduction in oxidant formation. At 100 nM they inhibited the proliferation of cultured keratinocytes. When keratinocytes were irradiated with 50–200 mJ/cm2 of UVB they also protected against DNA damage, and/or induced DNA repair by enhancing the repair of 6-4PP and attenuating CPD levels and the tail moment of comets. Treatment with test compounds increased expression of Nrf2-target genes involved in the antioxidant response including GR, HO-1, CAT, SOD1, and SOD2, with increased protein expression for HO-1, CAT, and MnSOD. The treatment also stimulated the phosphorylation of p53 at Ser-15, increased its concentration in the nucleus and enhanced Nrf2 translocation into the nucleus. In conclusion, pretreatment of keratinocytes with 1,25(OH)2D3 or CYP11A1-derived vitamin D3- or lumisterol hydroxy-derivatives, protected them against UVB-induced damage via activation of the Nrf2-dependent antioxidant response and p53-phosphorylation, as well as by the induction of the DNA repair system. Thus, the new vitamin D3 and lumisterol hydroxy-derivatives represent promising anti-photodamaging agents.
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The study was supported by NIH grants 1R01AR073004-01A1 and R01AR071189-01A1 and by a VA merit grant (no. 1I01BX004293-01A1) to ATS, United States.
Supplementary data to this article can be found online at https://doi.org/10.1016/j.redox.2019.101206.
Chaiprasongsuk, Anyamanee; Janjetovic, Zorica; Kim, Tae-Kang; Jarrett, Stuart G.; D'Orazio, John A.; Holick, Michael F.; Tang, Edith K. Y.; Tuckey, Robert C.; Panich, Uraiwan; Li, Wei; and Slominski, Andrzej T., "Protective Effects of Novel Derivatives of Vitamin D3 and Lumisterol Against UVB-Induced Damage in Human Keratinocytes Involve Activation of Nrf2 and p53 Defense Mechanisms" (2019). Toxicology and Cancer Biology Faculty Publications. 88.