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β-Arrestin-biased AT1R stimulation promotes cell survival during acute cardiac injury

Ki-Seok Kim1, Dennis Abraham, Barbara Williams

  • 1Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.

American Journal of Physiology. Heart and Circulatory Physiology
|August 14, 2012
PubMed

Insights

A novel biased ligand for the angiotensin II type 1 receptor (AT1R), TRV120023, demonstrated significant cardioprotection against cardiac injury by activating specific signaling pathways. This effect was dependent on β-arrestin-2, unlike traditional blockers.

Area of Science:

  • Cardiovascular Pharmacology
  • Molecular Cardiology
  • Drug Discovery

Background:

  • Pharmacological blockade of the angiotensin II type 1 receptor (AT1R) is standard for heart failure and hypertension.
  • Emerging evidence highlights β-arrestin-mediated AT1R signaling as crucial for cardioprotection.
  • Biased signaling ligands offer a potential new therapeutic strategy.

Purpose of the Study:

  • To investigate the cardioprotective effects of the β-arrestin-biased AT1R ligand TRV120023.
  • To compare TRV120023's efficacy against the traditional AT1R blocker losartan in acute cardiac injury models.
  • To elucidate the role of β-arrestin-2 in mediating TRV120023's effects.

Main Methods:

  • Utilized pressure-volume loop analyses to assess cardiac contractility.
  • Investigated MAPK and Akt signaling pathway activation.
  • Employed β-arrestin-2 knockout (KO) mice to determine the role of β-arrestin-2.
  • Induced cardiac injury via ischemia-reperfusion and mechanical stretch models.

Main Results:

  • TRV120023 enhanced cardiac contractility and blocked endogenous ANG II effects.
  • TRV120023 significantly activated MAPK and Akt pathways, unlike losartan.
  • TRV120023 demonstrated significant cytoprotection against cardiac injury, an effect absent in losartan-treated groups.
  • All observed hemodynamic and cardioprotective effects of TRV120023 were abolished in β-arrestin-2 KO mice.

Conclusions:

  • The β-arrestin-biased AT1R ligand TRV120023 exhibits distinct cardioprotective and functional properties compared to losartan.
  • TRV120023's beneficial effects are mediated through β-arrestin-2-dependent signaling.
  • This novel class of biased ligands may offer therapeutic advantages over conventional ARBs in acute cardiac injury settings.

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