Ang-(1-7) is an endogenous \u03b2-arrestin-biased agonist of the AT1 receptor with protective action in cardiac hypertrophy

Rafael M Costa,Lucas T Parreiras-E-Silva,Eduardo B Oliveira,Rita C Tostes,Carlos A A Silva,Deisy Y Rodríguez,Pedro A B Ferreira,Diego A Duarte,Larissa B Teixeira,Michel Bouvier,Claudio M Costa-Neto,Sarah C Simões,Emiliana P Abrao,Thiago Bruder-Nascimento

doi:10.1038/s41598-017-12074-3

Abstract

The renin-angiotensin system (RAS) plays a key role in the control of vasoconstriction as well as sodium and fluid retention mediated mainly by angiotensin (Ang) II acting at the AT1 receptor (AT1R). Ang-(1-7) is another RAS peptide, identified as the endogenous ligand of the Mas receptor and known to counterbalance many of the deleterious effects of AngII. AT1R signaling triggered by β-arrestin-biased agonists has been associated to cardioprotection. Because position 8 in AngII is important for G protein activation, we hypothesized that Ang-(1-7) could be an endogenous β-arrestin-biased agonist of the AT1R. Here we show that Ang-(1-7) binds to the AT1R without activating Gq, but triggering β-arrestins 1 and 2 recruitment and activation. Using an in vivo model of cardiac hypertrophy, we show that Ang-(1-7) significantly attenuates heart hypertrophy by reducing both heart weight and ventricular wall thickness and the increased end-diastolic pressure. Whereas neither the single blockade of AT1 or Mas receptors with their respective antagonists prevented the cardioprotective action of Ang1-7, combination of the two antagonists partially impaired the effect of Ang-(1-7). Taken together, these data indicate that Ang-(1-7) mediates at least part of its cardioprotective effects by acting as an endogenous β-arrestin-biased agonist at the AT1R.

Highlights

The renin-angiotensin system (RAS) is a critical regulator of cardiovascular and renal physiology, controlling among other functions, blood pressure, electrolyte balance and cardiac remodeling1
AngII binds to AngII type 1 (AT1) and type 2 (AT2) receptors, which belong to the G protein-coupled receptors (GPCRs) superfamily
Concerning the AT1 receptor (AT1R), it is well known that the last C-terminal amino acid residue (Phe8) of AngII plays a pivotal role in the agonistic properties of the ligand15,16, mainly by affecting the activation of G protein signaling cascades

Summary

Results and Discussion

Ang-(1-7) binds to the AT1 receptor but does not engage its canonical G protein signaling. Ang-(1-7) did not promote the separation of Gαq-RLucII from Gγ1-GFP10 at any of the concentrations tested in HEK293T cells transiently expressing AT1R This contrasted with the activation of Gq promoted by AngII, reflected by the dose-dependent decrease in BRET signal with a potency of 4.25 nM (Fig. 1B, Table 1). To previous reports that correlate β-arrestin-biased activation and ERK1/2 phosphorylation to cardioprotective effects38,39 These data clearly show that Ang-(1-7), classically known as the Mas receptor endogenous agonist, acts as a β-arrestin-biased agonist on the AT1R resulting in a signaling profile distinct from AngII. To investigate whether AT1R signaling contributes to the cardioprotective response associated with Ang-(1-7), we used an experimental model of cardiac hypertrophy that does not rely on AngII-mediated mechanisms50 To our knowledge, this is the first in vivo study that addressed possible Ang-(1-7) cardioprotective effects when acting as a β-arrestin-biased agonist of the AT1R. In addition to such known cardioprotective actions of the Mas receptor, our study unveils that Ang-(1-7) β-arrestin-biased mode of action at the AT1R may play a key role on such protective actions

Methods

Author Contributions

Additional Information