RGD Reference Report - Selective loss of fine tuning of Gq/11 signaling by RGS2 protein exacerbates cardiomyocyte hypertrophy. - Rat Genome Database

RGD Reference Report - Selective loss of fine tuning of Gq/11 signaling by RGS2 protein exacerbates cardiomyocyte hypertrophy. - Rat Genome Database

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Selective loss of fine tuning of Gq/11 signaling by RGS2 protein exacerbates cardiomyocyte hypertrophy.
Authors:	Zhang, Wei Anger, Thomas Su, Jialin Hao, Jianming Xu, Xiaomei Zhu, Ming Gach, Agnieszka Cui, Lei Liao, Ronglih Mende, Ulrike
Citation:	Zhang W, etal., J Biol Chem. 2006 Mar 3;281(9):5811-20. doi: 10.1074/jbc.M507871200. Epub 2005 Dec 26.
RGD ID:	13524577
Pubmed:	PMID:16380388 (View Abstract at PubMed)
DOI:	DOI:10.1074/jbc.M507871200 (Journal Full-text)
Alterations in cardiac G protein-mediated signaling, most prominently G(q/11) signaling, are centrally involved in hypertrophy and heart failure development. Several RGS proteins that can act as negative regulators of G protein signaling are expressed in the heart, but their functional roles are still poorly understood. RGS expression changes have been described in hypertrophic and failing hearts. In this study, we report a marked decrease in RGS2 (but not other major cardiac RGS proteins (RGS3-RGS5)) that occurs prior to hypertrophy development in different models with enhanced G(q/11) signaling (transgenic expression of activated Galpha(q)(*) and pressure overload due to aortic constriction). To assess functional consequences of selective down-regulation of endogenous RGS2, we identified targeting sequences for effective RGS2 RNA interference and used lipid-based transfection to achieve uptake of fluorescently labeled RGS2 small interfering RNA in >90% of neonatal and adult ventricular myocytes. Endogenous RGS2 expression was dose-dependently suppressed (up to 90%) with no major change in RGS3-RGS5. RGS2 knockdown increased phenylephrine- and endothelin-1-induced phospholipase Cbeta stimulation in both cell types and exacerbated the hypertrophic effect (increase in cell size and radiolabeled protein) in neonatal myocytes, with no major change in G(q/11)-mediated ERK1/2, p38, or JNK activation. Taken together, this study demonstrates that endogenous RGS2 exerts functionally important inhibitory restraint on G(q/11)-mediated phospholipase Cbeta activation and hypertrophy in ventricular myocytes. Our findings point toward a potential pathophysiological role of loss of fine tuning due to selective RGS2 down-regulation in G(q/11)-mediated remodeling. Furthermore, this study shows the feasibility of effective RNA interference in cardiomyocytes using lipid-based small interfering RNA transfection.

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Biological Process

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Term	Qualifier	Evidence	With	Reference	Notes	Source	Original Reference(s)
negative regulation of cell growth involved in cardiac muscle cell development		IMP		13524577		RGD

Objects Annotated

Genes (Rattus norvegicus)

Rgs2 (regulator of G-protein signaling 2)

Additional Information