Biased Agonism of the Angiotensin II Type I Receptor

Int Heart J. 2015;56(5):485-8. doi: 10.1536/ihj.15-256. Epub 2015 Jul 14.

Abstract

Angiotensin II (AngII) type I receptor (AT1R) recognizes AngII, a cardiovascular peptide hormone that acts as a terminal effector of the renin-angiotensin system (RAS). AT1R belongs to the rhodopsin-like peptidergic family of G protein-coupled receptors (GPCRs) and serves as a therapeutic target for the treatment of cardiovascular diseases, such as hypertension, cardiac hypertrophy and heart failure. Classically, AT1R was considered to signal only through G proteins. However, recent studies have revealed that AT1R is capable of activating G protein-independent signaling that is mediated by β-arrestins. β-arrestin is a cytosolic scaffold that is recruited to the activated GPCRs. In vitro and ex vivo studies have demonstrated that the activation of the AT1R-β-arrestin pathway stimulates contractility and exerts prosurvival effects in cardiomyocytes. TRV027, a potent synthetic β-arrestin-biased ligand for AT1R, specifically activates AT1R-β-arrestin signaling without stimulating G proteins. In preclinical studies, TRV027 not only produced vasodilation by antagonizing the AT1R-Gαq pathway but also enhanced cardiac performance by activating AT1R-β-arrestin signaling. Because of this unique pharmacological profile, TRV027 is now being evaluated in a phase II clinical trial as a novel therapeutic for acute heart failure (AHF).

Publication types

  • Review

MeSH terms

  • Angiotensin II Type 1 Receptor Blockers / pharmacology
  • Arrestins / metabolism
  • Clinical Trials, Phase II as Topic
  • Heart Failure* / drug therapy
  • Heart Failure* / metabolism
  • Heart Failure* / pathology
  • Humans
  • Myocytes, Cardiac* / drug effects
  • Myocytes, Cardiac* / metabolism
  • Oligopeptides / pharmacology*
  • Receptor, Angiotensin, Type 1 / metabolism*
  • Renin-Angiotensin System / drug effects*
  • Signal Transduction / drug effects
  • beta-Arrestins

Substances

  • Angiotensin II Type 1 Receptor Blockers
  • Arrestins
  • Oligopeptides
  • Receptor, Angiotensin, Type 1
  • beta-Arrestins
  • Sar-Arg-Val-Tyr-Ile-His-Pro-Ala-OH