Angiotensin II upregulates cyclophilin A by enhancing ROS production in rat cardiomyocytes

Angiotensin II (Ang II) is a principal molecule of the renin-angiotensin system, which promotes hypertrophy and fibrosis. It has been demonstrated that Ang II upregulates the expression of cyclophilin A (CypA), which is a potential myocardial hypertrophy factor. However, the mechanisms by which Ang II induces the expression of CypA in cardiomyocytes remain unclear. In the present study, reactive oxygen species (ROS) were detected by fluorescence microscopy, and western blot analysis and ELISA were used to measure CypA expression. It was identified that Ang II enhanced the production of ROS in rat cardiomyocytes. ROS, in turn, promoted CypA expression and secretion. Notably, the action of Ang II was primarily dependent on the angiotensin type 2 receptor (AT(2)R), not the type 1 receptor. These results provided an insight into the role of the AT(2)R signaling pathway in Ang II-induced myocardial hypertrophy.