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

Aim: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

angiotensin II type‐2 receptor; angiotensin‐(1–7); apoptosis; autophagy; cardiac hypertrophy; mas receptor.