# Angiotensin‐(1–7) Alleviates Isoproterenol‐Induced Cardiac Hypertrophy by Suppressing Autophagy and Apoptosis Through the Synergistic Action of Mas Receptor and Angiotensin II Type 2 Receptor

## TL;DR

This study shows that Angiotensin-(1–7) reduces heart enlargement caused by isoproterenol by suppressing cell death and self-destruction through the teamwork of two receptors.

## Contribution

The novel finding is that Angiotensin-(1–7) protects the heart via synergistic signaling between Mas receptor and Angiotensin II type 2 receptor.

## Key findings

- Angiotensin-(1–7) reduced heart dysfunction and enlargement in mice with ISO-induced hypertrophy.
- Mas receptor and Angiotensin II type 2 receptor work together to suppress apoptosis and autophagy.
- Blocking both receptors reversed the protective effects of Angiotensin-(1–7).

## Abstract

The aim of this study is to determine whether Angiotensin‐(1–7) [Ang‐(1–7)] alleviates isoproterenol (ISO)–induced cardiac hypertrophy by suppressing excessive autophagy and apoptosis through coordinated Mas receptor (MasR) and angiotensin II type‐2 receptor (AT2R) signaling, and to elucidate the underlying mechanisms.

ISO‐induced hypertrophy was established in mice and assessed by echocardiography, histology, and hypertrophic markers. H9c2 cardiomyocytes were exposed to ISO and treated separately with A‐779 (MasR antagonist), PD123319 (AT2R antagonist), and a combination of both receptor antagonists. Receptor interplay was examined using pharmacological blockade and co‐immunoprecipitation. Autophagy and apoptosis were evaluated by transmission electron microscopy and TUNEL.

Ang‐(1–7) attenuated ventricular dysfunction, myocardial enlargement, and upregulation of hypertrophic markers in mice with ISO‐induced hypertrophy. Pharmacological inhibition with A‐779 and PD123319 revealed that Ang‐(1–7) actions require reciprocal regulation between MasR and AT2R. Both receptors synergistically contributed to the anti‐apoptotic effect, while the anti‐autophagic response was mediated predominantly by MasR. Transmission electron microscopy and TUNEL staining confirmed that Ang‐(1–7) treatment alleviated excessive autophagy and apoptosis in cardiomyocytes. Furthermore, experiments with dual receptor antagonists and co‐immunoprecipitation showed an interaction between MasR and AT2R, supporting their coordinated signaling role in cardiac protection.

Ang‐(1–7) ameliorates ISO‐induced cardiac hypertrophy by suppressing excessive autophagy and apoptosis via synergistic MasR–AT2R signaling. Receptor crosstalk may represent a therapeutic entry point for pathological hypertrophy.