912 Mouse skin-derived precursors’ anti-UVB radiation damage through TGF-β/Smad pathway activation via thrombospondin 1

Abstract

Former research indicated mouse skin-derived precursors (mSKPs) might have the capacity of anti-UVB radiation. The mechanisms might be associated with TGF-β/Smad pathway and thrombospondin 1 (TSP1). This study was to investigate mSKPs’ response to UVB radiation, and to study the role of TSP1 in TGF-β/Smad pathway in mSKPs’ anti-UVB radiation damage, as compared with dermal mesenchymal stem cells (DMSCs). Cell survival rate, senescence and death were determined. TSP1 and TGF-β1 in supernatant were tested. Gene and protein expression of TSP1, TGF-β1, MMP1, collagen I, smad2/3, and p-smad2/3 was measured. mSKPs’ survival rate decreased 24h after UVB radiation, but increased at 48h and 72h. DMSCs’ survival rate kept decreasing after radiation. Cell senescence and death 24h after radiation, but recovery at 48h were noticed in mSKPs. The recovery was not obvious in DMSCs. TSP1 and TGF-β1 in mSKPs’ supernatant increased 6h, 12h, and 24h after radiation (p<0.05). No significant change was noticed in DMSCs’ supernatant. In mSKPs, gene expression of TSP1, TGF-β1, MMP1, and collagen I increased 3h, 6h after radiation (p<0.01), decreased at 12h, 24h (p<0.01). In DMSCs, expression of TSP1 and collagen I decreased after radiation (p<0.05), expression of MMP1 increased after radiation (p<0.01), expression of TGF-β1 decreased 3h after radiation (p<0.01), increased at other time points (p<0.01). In mSKPs, protein expression of TSP1, TGF-β1, MMP1, and p-smad2/3 increased 6h, 12h, and 24h after radiation (p<0.05), expression of smad2/3 decreased after radiation (p<0.05). Expression of collagen I increased 6h, 12h after radiation (p<0.01), decreased at 24h (p<0.05). In DMSCs, expression of TGF-β1 and MMP1 increased after radiation (p<0.01), and expression of other proteins decreased (p<0.01). Radiation damage after UVB radiation were observed in mSKPs and DMSCs. The recovery was noticed in mSKPs, and one of the mechanisms might be the activation of TGF-β/Smad pathway by TSP1. In DMSCs, the recovery was not noticed, and there might be other mechanisms.