TGFB1 and renal fibrosis: Although the origin of interstitial myofibroblasts during renal fibrosis is controversial, TGF-β1 is a key mediator activating various cells, such as tubular epithelial cells, resident fibroblasts, and bone marrow–derived mesenchymal stem cells whereby they lose their normal phenotypes and acquire a myofibroblast phenotype, accelerating matrix synthesis in renal fibrosis33,38,39.