Endothelial CHOP as a central mechanism in renovascular hypertension-induced vascular endothelial dysfunction and cardiac fibrosis.

OBJECTIVE: In this study, we sought to determine the significant impact of the vascular endothelial endoplasmic reticulum (ER) stress C/EBP homologous protein (CHOP) in renovascular hypertension-induced vascular endothelial dysfunction and cardiac fibrosis. APPROACH AND RESULTS: Eight-week-old male and female CHOP(flox/flox) and EC(CHOP-/-) mice were randomly divided into eight groups with and without 2-Kidney-1-Clip (2K1C) surgery for four weeks. Body weight, systolic blood pressure, running performance, cardiac hypertrophy and fibrosis, lung edema, inflammation, vascular endothelial function, and signaling were assessed. For the mechanism, we utilized human coronary endothelial cells, both with and without CHOP down-regulation, and then stimulated them with and without angiotensin II ± ATP to determine eNOS phosphorylation level and the presence of inflammatory factors. Male and female CHOP(flox/flox) mice subjected to 2K1C for four weeks exhibited hypertension, cardiac hypertrophy and fibrosis, lung edema, impaired running performance, endothelium-dependent vascular relaxation dysfunction, reduction in eNOS phosphorylation, and inflammation induction. In contrast, male and female EC(CHOP-/-) mice subjected to 2K1C for four weeks were protected against the pathogenesis of renovascular hypertension. In vitro, data showed that deletion of CHOP in endothelial cells protected eNOS phosphorylation level and blunted the induction of inflammation in response to angiotensin II ± ATP. CONCLUSION: Our research findings determined that CHOP is a central mechanism driving vascular endothelial dysfunction and cardiac fibrosis in renovascular hypertension. Therefore, targeting CHOP in endothelial cells could be a potential therapeutic approach to protect against the pathogenesis of renovascular hypertension.