POU4F1 and renal fibrosis: Targeting P2Y12 can block TGF‐β/Smad3‐mediated MMT and progressive renal fibrosis.[59] Two targets of Smad3 in renal fibrosis, Pou4f1[55] and proto‐oncogene tyrosine protein kinase Src,[60] were proved to be crucial downstream regulators of MMT.