Canonical mediators and molecular pathways in renal fibrosis. Many injurious stimuli converge on the TGF-β pathway, which has context-dependent pleiotropic effects and interacts with several related pathways. AGEs, advanced glycation end products; BMP-7, bone morphogenetic protein 7; FzR, frizzled receptor; HGF, hepatocyte growth factor; HIF, hypoxia-inducible factor; ROS, reactive oxygen species.