Nonpeptide AVE 0991 is an angiotensin-(1-7) receptor Mas agonist in the mouse kidney

It has been described recently that the nonpeptide AVE 0991 (AVE) mimics the effects of angiotensin-(1-7) [Ang-(1-7)] in bovine endothelial cells. In this study, we tested the possibility that AVE is an agonist of the Ang-(1-7) receptor Mas, in vitro and in vivo. In water-loaded C57BL/6 mice, AVE (0.58 nmol/g body weight) produced a significant reduction in urinary volume (0.06 +/- 0.03 mL/60 min [n = 9] versus 0.27 +/- 0.05 [n = 9]; P < 0.01), associated with an increase in urinary osmolality. The Ang-(1-7) antagonist A-779 completely blocked the antidiuretic effect of AVE. As observed previously for Ang-(1-7), the antidiuretic effect of AVE after water load was blunted in Mas-knockout mice (0.37 +/- 0.10 mL/60 min [n = 9] versus 0.27 +/- 0.03 mL/60 min [n = 11] AVE-treated mice). In vitro receptor autoradiography in C57BL/6 mice showed that the specific binding of I-125-Ang-(1-7) to mouse kidney slices was displaced by AVE, whereas no effects were observed in the binding of I-125-angiotensin II or I-125-angiotensin IV. Furthermore, AVE displaced the binding of I-125-Ang-(1-7) in Mas-transfected monkey kidney cells (COS) cells (IC50 = 4.75 x 10(-8) mol/L) and of rhodamine-Ang-(1-7) in Mas-transfected Chinese hamster ovary (CHO) cells. It also produced NO release in Mas-transfected CHO cells blocked by A-779 but not by angiotensin II type-1 (AT1) and AT2 antagonists. Contrasting with these data, the antidiuretic effect of AVE was totally blocked by AT2 antagonists and partially blocked (approximate to 60%) by AT1 antagonists. The binding data, the results obtained in Mas-knockout mice and in Mas-transfected cells, show that AVE is a Mas receptor agonist. Our data also suggest the involvement of AT(2)/AT(1)-related mechanisms, including functional antagonism, oligomerization or cross-talk, in the renal responses to AVE.