Islet-1 is a dual regulator of fibrogenic epithelial-to-mesenchymal transition in epicardial mesothelial cells

► Islet-1 is a dual regulator of cardiac epithelial-to-mesenchymal transition (EMT). ► Islet-1 promotes mesenchymal features in epicardial mesothelial cells via myocardin. ► Islet-1 is reduced during TGF-β-induced EMT, which inhibits the EMT process. ► Mechanistically, Islet-1 is reduced by microRNA-31 and β-catenin during EMT.