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. 2017 Sep 19;7(1):11903.
doi: 10.1038/s41598-017-12074-3.

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

Larissa B Teixeira  1 , Lucas T Parreiras-E-Silva  1 , Thiago Bruder-Nascimento  2 , Diego A Duarte  1 , Sarah C Simões  1 , Rafael M Costa  2 , Deisy Y Rodríguez  1 , Pedro A B Ferreira  2 , Carlos A A Silva  2 , Emiliana P Abrao  2 , Eduardo B Oliveira  1 , Michel Bouvier  3 , Rita C Tostes  2 , Claudio M Costa-Neto  4
Affiliations

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

Larissa B Teixeira et al. Sci Rep. .

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.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1
Comparative analyses of Ang-(1-7) and AngII acting at the AT1 receptor: binding and analyses of G protein activation pathways. (A) Competition binding profiles for AngII and Ang-(1-7) against [3H]AngII in HEK293T cells transiently expressing the AT1R. Data are expressed as percentages of the maximum specific binding of the radioligand. AngII and Ang-(1-7) effects on Gq activation (B), intracellular Ca2+ mobilization (C) and Gi3 activation (D). All data were generated from at least 3 independent experiments.
Figure 2
Figure 2
Comparative analyses of Ang-(1-7) and AngII acting at the AT1 receptor to induce β-arrestins recruitment, β-arrestins conformational changes, and ERK1/2 phosphorylation. Concentration-response curves for Ang-(1-7) and AngII were generated to evaluate the recruitment of β-arrestin 1 (A) or β-arrestin 2 (B) to the AT1R by BRET. The abilities of the ligands to trigger β-arrestin activation, as evaluated by conformational rearrangements of β-arrestin 1 (C) or β-arrestin 2 (D), were monitored by intramolecular BRET as described in Methods. Kinetics of ERK1/2 phosphorylation after stimulation with 100 nM AngII or 1 μM Ang-(1-7) (E). Data were generated from at least 4 independent experiments. Blots were cropped for conciseness of the presentation; full-length blots are presented in Supplementary Figure S1.
Figure 3
Figure 3
Effect of Ang-(1-7) on cardiac hypertrophy and increased end-diastolic pressure induced by isoproterenol. Cardiac hypertrophy was determined by heart weight/body weight ratio (HW/BW) (A), left ventricular wall thickness (B,C), and end-diastolic pressure (EDP) (D). Representative images of hearts from different groups of treatment stained with hematoxylin and eosin are shown in C. Wistar rats were treated with either vehicle or Isoproterenol (Iso) (2 mg/kg per day, i.p. for 7 days). Rats were also treated for 7 days with Ang-(1-7) (24 μg/kg per hour, Alzet osmotic mini-pump), Ang-(1-7) + losartan (AT1R selective antagonist, 10 mg/kg per day orally), Ang-(1-7) + A779 (Mas receptor selective antagonist, 744 μg/kg per day i.p.), or Ang-(1-7) + Losartan + A779 (same doses as described). Scale bars in the representative heart images = 2 mm. Bars represent the mean ± SEM (n = 6 vehicle, n = 6 Iso, n = 4 Iso + Losartan, n = 4 Iso + A779, n = 4 Iso + A779 + Losartan). *P < 0.05 vs. control; #P < 0.05 vs. Iso treatment. ns: not significant.
Figure 4
Figure 4
Schematic representation of the possible mechanism by which Ang-(1-7) plays its protective role in cardiac hypertrophy. AT1R is the main receptor for AngII, a GPCR coupled to Gq that leads to calcium release and modulation of signaling pathways related to cardiodeleterious effects, including cardiac hypertrophy. Besides G protein activation, AngII binding to AT1R also leads to β-arrestin recruitment, impairing G protein signaling and inducing receptor internalization. AT1R coupling to β-arrestin also initiates a subset of arrestin-dependent signaling pathways, which have been involved in cardioprotective effects. Ang-(1-7) is known as the Mas receptor endogenous ligand, reported to trigger some of its signal transduction by activation of PLA2/AA and PI3K/AKT,–, exerting physiological outcomes that counteract the AngII/AT1R cardiodeleterious effects. Here we show that Ang-(1-7) also binds to AT1R, but in a β-arrestin biased fashion, leading to attenuation of cardiac hypertrophy. These data suggest that some of the known cardioprotective Ang-(1-7) effects may also occur due to activation of AT1R in a β-arrestin-biased way. Indeed, our data show that the individual blockage of either AT1R or Mas receptor with their selective antagonists was not able to revert the cardioprotective effects induced by Ang-(1-7). The combined use of both AT1R and Mas receptor antagonists partially reverted the Ang-(1-7) effects, suggesting the involvement of both receptors, but was still not able to fully revert them, indicating that Ang-(1-7) effects could depend upon its interaction with other targets.
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References

    1. Karnik SS, et al. International Union of Basic and Clinical Pharmacology. XCIX. Angiotensin Receptors: Interpreters of Pathophysiological Angiotensinergic Stimuli [corrected] Pharmacological reviews. 2015;67:754–819. doi: 10.1124/pr.114.010454. - DOI - PMC - PubMed
    1. Kobori H, Nangaku M, Navar LG, Nishiyama A. The intrarenal renin-angiotensin system: from physiology to the pathobiology of hypertension and kidney disease. Pharmacological reviews. 2007;59:251–287. doi: 10.1124/pr.59.3.3. - DOI - PubMed
    1. Santos RA, Brosnihan KB, Jacobsen DW, DiCorleto PE, Ferrario CM. Production of angiotensin-(1-7) by human vascular endothelium. Hypertension. 1992;19:II56–61. doi: 10.1161/01.HYP.19.2_Suppl.II56. - DOI - PubMed
    1. Ferrario CM, Chappell MC. A new myocardial conversion of angiotensin I. Current opinion in cardiology. 1994;9:520–526. doi: 10.1097/00001573-199409000-00004. - DOI - PubMed
    1. Pereira MG, et al. Angiotensin II-independent angiotensin-(1-7) formation in rat hippocampus: involvement of thimet oligopeptidase. Hypertension. 2013;62:879–885. doi: 10.1161/HYPERTENSIONAHA.113.01613. - DOI - PubMed

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