The angiotensin II type 1 receptor mediates the induction of oxidative stress, apoptosis, and autophagy in HUVECs induced by angiotensin II

Abstract

Angiotensin (Ang) II, which is the central effector of the renin-angiotensin system (RAS), is one of the principal mediators of vascular dysfunction in hypertension and cardiovascular diseases. Proper vascular function is mediated by oxidative stress, cell apoptosis, and autophagy. However, the underlying signaling pathways and the major RAS components involved in this process are still not fully understood. In the present study, the effect of Ang II on reactive oxygen species (ROS) production, apoptosis induction, and autophagy in human umbilical vein endothelial cells (HUVECs) was investigated. An Annexin V kit was used for the apoptosis analysis, and caspase-3/7 activities were measured with the Caspase-Glo 3/7 Assay Kit. ROS production was measured using a 2,7-dichlorodihydrofluorescein diacetate probe whereas detection of autophagy was performed using acridine orange staining. We found that Ang II increases oxidative stress via ROS production, cell apoptosis via caspase 3/7, and the mitochondrial membrane potential (MMP). Interestingly, losartan, being an antagonist of the angiotensin II type 1 receptor (AT1R), has demonstrated the ability to restore autophagy levels to that of the control group subsequent to its induction by Ang II. The latter can thus induce endothelial cell damage, through excessive oxidative stress and defective autophagy-related apoptosis, which can be inhibited by losartan. These findings reinforce the pivotal role played by the Ang II/AT1R axis in the pathogenesis of vascular damage and bolster our knowledge of the role played by ROS/autophagy-related apoptosis via AT1R in the pathogenesis of hypertension and vascular diseases.