ACTA1 and renal fibrosis: The α-SMA and fibronectin staining showed PDGF-BB increased their expression following IR injury, which was inhibited by b-pEPCs administration (Figure S8B), indicating that PDGF-BB activated PDGFR-β-positive pericytes and accelerated renal fibrosis, which was attenuated by b-pEPCs treatment.