Curcumin alleviates TGF-β1-induced fibrosis in NRK-49F cells via suppression of miR-21 expression,and regulation of the TGF-β1/smad3 signaling pathway

Objective:Overexpression of microRNA-21(miR-21)has been well-recognized during fibrosis in a wide range of tissue types through regulation of fibrogenesis via diverse pathways.Curcumin exhibits antifibrotic effects in various organs.We and others have previously demonstrated that curcumin has positive effects on the protection against fibrosis.However,the effect of curcumin on miR-21 expression has not been reported.Methods:In this study,transforming growth factor-b1(TGF-b1)-stimulated rat renal fibroblast cells(NRK-49F)were transfected with miR-21 inhibitors,then the expression of Smad3,a-smooth muscle actin(a-SMA),type I collagen(COL1A1),and type III collagen(COL3A1)was determined using quantitative real-time-PCR(qRT-PCR)and western blot analysis.The effect of curcumin on production of the extracellular matrix was evaluated using immunofluorescence,qRT-PCR,and western blot analysis.Results:TGF-b1 stimulation upregulated the expression of miR-21 and induced fibrogenesis in NRK-49F cells.Transfection with miR-21 inhibitors selectively decreased smad3 activity,and noticeably reduced the expression of a-SMA,COL1A1,and COL3A1.Curcumin treatment significantly inhibited the expressions of smad3,a-SMA,COL1A1,COL3A1,as well as miR-21 expression in NRK-49F cells in a dosedependent manner.Conclusion:Curcumin exerted its anti-fibrotic effects by targeting the TGF-b1/smad3 signaling pathway and suppressing miR-21 expression,thereby provides novel insight in the protective effects of curcumin against fibrosis in various organs.

Projection of Landslides in China during the 21st Century under the RCP8.5 Scenario

More and more rainstorms and other extreme weather events occur in the context of global warming, which may increase the risks of landslides. In this paper, changes of landslides in the 21 st century of China under the high emission scenario RCP8.5(Representative Concentration Pathway) are projected by using a statistical landslide forecasting model and the regional climate model RegCM4.0. The statistical landslide model is based on an improved landslide susceptibility map of China and a rainfall intensity–duration threshold. First, it is driven by observed rainfall and RegCM4.0 rainfall in 1980–99, and it can reproduce the spatial distribution of landslides in China pretty well.Then, it is used to forecast the landslide changes over China in the future under the RCP8.5 scenario. The results consistently reveal that landslides will increase significantly in most areas of China, especially in the southeastern, northeastern, and western parts of Northwest China. The change pattern at the end of the 21 st century is generally consistent with that in the middle of the 21 st century, but with larger increment and magnitude. In terms of the probability,the proportion of grid points that are very likely and extremely likely to experience landslides will also increase.