TGFB1 and renal fibrosis: To investigate the function of miR-146a-5p regulated by BM-MSCs in the progression of renal fibrosis in vitro, we transiently transfected miR-146a-5p mimics into TGF-β1-treated mRTECs to significantly up-regulate the expression of miR-146a-5p (Figure 3C).