Ang 1-7 increases nitric oxide synthesis by modulating endothelial nitric oxide synthase-caveolin-1 interaction in rat vascular smooth muscle cells

Abstract

Background: We aimed to explore the potential protective effect of angiotensin (Ang) 1-7 in rat vascular smooth muscle cells (VSMCs) following exposure to high glucose and the mechanism of its effect on nitric oxide (NO) synthesis.Methods: Rat VSMCs were cultured with/without high glucose, Ang 1-7, and methyl-β-cyclodextrin (MβCD). The expression levels of caveolin-1 (Cav-1), inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS)/phosphorylated eNOS (Ser1177) were evaluated by western blotting and immunofluorescence staining. NO, superoxide dismutase (SOD), malondialdehyde (MDA) and peroxynitrite (ONOO-) levels in cell culture supernatants were measured by enzyme-linked immunosorbent assay. Intracellular calcium content was determined by flow cytometry.Results: VSMCs cultured with high glucose exhibited striking increases in Cav-1, MDA, iNOS, ONOO-, and intracellular Ca2+, as well as reductions in eNOS phosphorylation, SOD, and NO production. Ang 1-7 treatment reversed the effects of high glucose in these cells.Conclusion: Ang 1-7 increases NO synthesis by regulating Cav-1 expression, Cav-1–eNOS interaction, oxidative stress, and intracellular Ca2+ levels in rat VSMCs cultured in high glucose.