AVE 0991, a nonpeptide mimic of the effects of angiotensin-(1-7) on the endothelium

Recently, we demonstrated that the heptapeptide angiotensin-(1-7) (Ang-[1-7]) exhibits a favorable kinetic of nitric oxide (NO) release accompanied by extremely low superoxide (O₂^-) production. In this report we describe AVE 0991, a novel nonpeptide compound that evoked effects similar to Ang-(1-7) on the endothelium. AVE 0991 and unlabeled Ang-(1-7) competed for high-affinity binding of [¹²⁵I]-Ang-(1-7) to bovine aortic endothelial cell membranes with IC₅₀ values of 21±35 and 220±280 nmol/L, respectively. Stimulated NO and O₂^- release from bovine aortic endothelial cells was directly and simultaneously measured on the cell surface by selective electrochemical nanosensors. Peak concentrations of NO and O₂^- release by AVE 0991 and Ang-(1-7) (both 10 μmol/L) were not significantly different (NO: 295±20 and 270±25 nmol/L; O₂^-: 18±2 and 20±4 nmol/L). However, the released amount of bioactive NO was ≈5 times higher for AVE 0991 in comparison to Ang-(1-7). The selective Ang-(1-7) antagonist [D-Ala⁷]-Ang-(1-7) inhibited the AVE 0991-induced NO and O₂^- production by ≈50%. A similar inhibition level was observed for the Ang II AT₂ receptor antagonist EXP 3174. In contrast, the Ang II AT₂ receptor antagonist PD 123,177 inhibited the AVE 0991-stimulated NO production by ≈90% but without any inhibitory effect on O₂^- production. Both NO and O₂^- production were inhibited by NO synthase inhibition (≈70%) and by bradykinin B₂ receptor blockade (≈80%). AVE 0991 efficiently mimics the effects of Ang-(1-7) on the endothelium, most probably through stimulation of a specific, endothelial Ang-(1-7)-sensitive binding site causing kinin-mediated activation of endothelial NO synthase.