Tanshinone IIA down-regulated p-Smad3 signaling to inhibit TGF-β1-mediated fibroblast proliferation via lncRNA-HSRL/SNX9

Introduction Tanshinone IIA (TSIIA), an active component of Salvia miltiorrhiza (Danshen), is reported to inhibit cell proliferation in hypertrophic scars (HS). In our previous study, we observed that lncRNA human-specific regulatory loci (HSRL) was up-regulated in HS tissues. However, whether TSIIA serves as an effective treatment for HS through affecting HSRL is still unexplored. Methods TGF-β1-stimulated fibroblast were used as the in vitro HS model. The effects of TSIIA on cell proliferation were evaluated using CCK-8, Edu staining and colony formation assays. By performing loss-of-function and rescue experiments, we explored the role of HSRL and Sorting nexin 9 (SNX9) in TGF-β1-stimulated fibroblast. Employing RNA-protein pull-down assay and Co-immunoprecipitation, we further investigated the mechanisms through which TSIIA attenuated TGF-β1-stimulated fibroblast. Results Our data demonstrated that TSIIA could effectively attenuate TGF-β1-mediated fibroblast proliferation in a dose-dependent manner. Meanwhile, TSIIA could down-regulate the expression of α-SMA, VEGFA, Collagen 1, HSRL, SNX9 and p-Smad2/3 in TGF-β1-stimulated HSF. In addition, we found that SNX9 overexpression reversed the effects of HSRL knockdown on TGF-β1-stimulated HSF. Furthermore, we confirmed that TSIIA treatment weakens the interaction between p-Smad3 and SNX9 in HS models. Conclusions Tanshinone IIA down-regulated p-Smad3 signaling to inhibit TGF-β1-mediated fibroblast proliferation via lncRNA-HSRL/SNX9.