Angiotensin IV attenuates diabetic cardiomyopathy <i>via</i> suppressing FoxO1-induced excessive autophagy, apoptosis and fibrosis

The rennin-angiotensin-aldosterone system (RAAS) plays a critical role in the pathogenesis of diabetic cardiomyopathy, but the role of a member of RAAS, angiotensin IV (Ang IV), in this disease and its underlying mechanism are unclear. This study was aimed to clarify the effects of Ang IV and its downstream mediator forkhead box protein O1 (FoxO1) on diabetic cardiomyopathy. Methods: In vivo, diabetic mice were treated with low-, medium-and high-dose Ang IV, AT4R antagonist divalinal, FoxO1 inhibitor AS1842856 (AS), or their combinations. In vitro, H9C2 cardiomyocytes and cardiac fibroblasts were treated with different concentrations of glucose, low-, medium-and high-dose Ang IV, divalinal, FoxO1-overexpression plasmid (FoxO1-OE), AS, or their combinations. Results: Ang IV treatment dose-dependently attenuated left ventricular dysfunction, fibrosis, and myocyte…