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Dual loss of regulator of G protein signaling 2 and 5 exacerbates ventricular myocyte arrhythmias and disrupts the fine-tuning of Gi/o signaling
Journal article   Open access   Peer reviewed

Dual loss of regulator of G protein signaling 2 and 5 exacerbates ventricular myocyte arrhythmias and disrupts the fine-tuning of Gi/o signaling

Shelby A. Dahlen, Tyler F. Bernadyn, Alethia J. Dixon, Bo Sun, Jingsheng Xia, Elizabeth A. Owens and Patrick Osei-Owusu
Journal of molecular and cellular cardiology, v 170, pp 34-46
Sep 2022
DOI: https://doi.org/10.1016/j.yjmcc.2022.05.009
Featured in Collection :   UN Sustainable Development Goals @ Drexel
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https://doi.org/10.1016/j.yjmcc.2022.05.009View
Published, Version of Record (VoR)CC BY-NC-ND V4.0,  Open

Abstract

Arrhythmia cAMP Cardiac excitation-contraction coupling Cardiomyopathy Catecholamine G protein signaling RGS proteins
Cardiac contractility, essential to maintaining proper cardiac output and circulation, is regulated by G protein-coupled receptor (GPCR) signaling. Previously, the absence of regulator of G protein signaling (RGS) 2 and 5, separately, was shown to cause G protein dysregulation, contributing to modest blood pressure elevation and exaggerated cardiac hypertrophic response to pressure-overload. Whether RGS2 and 5 redundantly control G protein signaling to maintain cardiovascular homeostasis is unknown. Here we examined how the dual absence of RGS2 and 5 (Rgs2/5 dbKO) affects blood pressure and cardiac structure and function. We found that Rgs2/5 dbKO mice showed left ventricular dilatation at baseline by echocardiography. Cardiac contractile response to dobutamine stress test was sex-dependently reduced in male Rgs2/5 dbKO relative to WT mice. When subjected to surgery-induced stress, male Rgs2/5 dbKO mice had 75% mortality within 72–96 h after surgery, accompanied by elevated baseline blood pressure and decreased cardiac contractile function. At the cellular level, cardiomyocytes (CM) from Rgs2/5 dbKO mice showed augmented Ca2+ transients and increased incidence of arrhythmia without augmented contractile response to electrical field stimulation (EFS) and activation of β-adrenergic receptors (βAR) with isoproterenol. Dual loss of Rgs2 and 5 suppressed forskolin-induced cAMP production, which was restored by Gi/o inactivation with pertussis toxin that also reduced arrhythmogenesis during EFS or βAR stimulation. Cardiomyocyte NCX and PMCA mRNA expression was unaffected in Rgs2/5 dbKO male mice. However, there was an exaggerated elevation of EFS-induced cytoplasmic Ca2+ in the presence of SERCA blockade with thapsigargin. We conclude that RGS2 and 5 promote normal ventricular rhythm by coordinating their regulatory activity towards Gi/o signaling and facilitating cardiomyocyte calcium handling. [Display omitted] •Dual loss of Rgs2 and 5 causes left ventricular dilatation, arrhythmias, and sex-related death following surgery-induced stress.•Myocytes null for Rgs2 &5 are prone to βAR and EFS-induced arrhythmias with exagerated and sustained Ca2+ elevation.•Inhibition of Gi/o markedly reduces arrhythmia incidence in Rgs2/5 dbKO cardiomyocytes.•RGS2 and 5 coordinate their G protein regulatory activity to finetune Gi/o signaling in ventricular myocytes.

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Collaboration types
Domestic collaboration
Web of Science research areas
Cardiac & Cardiovascular Systems
Cell Biology
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