Regulator of G protein signaling 2 mediates cardiac compensation to pressure overload and antihypertrophic effects of PDE5 inhibition in mice

Eiki Takimoto, Norimichi Koitabashi, Steven Hsu, Elizabeth A. Ketner, Manling Zhang, Takahiro Nagayama, Djahida Bedja, Kathleen L. Gabrielson, Robert Blanton, David P. Siderovski, Michael E. Mendelsohn, David A. Kass

Research output: Contribution to journalArticle

151 Scopus citations

Abstract

The heart initially compensates for hypertension-mediated pressure overload by enhancing its contractile force and developing hypertrophy without dilation. Gq protein-coupled receptor pathways become activated and can depress function, leading to cardiac failure. Initial adaptation mechanisms to reduce cardiac damage during such stimulation remain largely unknown. Here we have shown that this initial adaptation requires regulator of G protein signaling 2 (RGS2). Mice lacking RGS2 had a normal basal cardiac phenotype, yet responded rapidly to pressure overload, with increased myocardial Gq signaling, marked cardiac hypertrophy and failure, and early mortality. Swimming exercise, which is not accompanied by Gq activation, induced a normal cardiac response, while Rgs2 deletion in Gαq-overexpressing hearts exacerbated hypertrophy and dilation. In vascular smooth muscle, RGS2 is activated by cGMP-dependent protein kinase (PKG), suppressing Gq-stimulated vascular contraction. In normal mice, but not Rgs2-/- mice, PKG activation by the chronic inhibition of cGMP-selective phosphodiesterase 5 (PDE5) suppressed maladaptive cardiac hypertrophy, inhibiting Gq-coupled stimuli. Importantly, PKG was similarly activated by PDE5 inhibition in myocardium from both genotypes, but PKG plasma membrane translocation was more transient in Rgs2-/- myocytes than in controls and was unaffected by PDE5 inhibition. Thus, RGS2 is required for early myocardial compensation to pressure overload and mediates the initial antihypertrophic and cardioprotective effects of PDE5 inhibitors.

Original languageEnglish
Pages (from-to)408-420
Number of pages13
JournalJournal of Clinical Investigation
Volume119
Issue number2
DOIs
StatePublished - 2 Feb 2009

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    Takimoto, E., Koitabashi, N., Hsu, S., Ketner, E. A., Zhang, M., Nagayama, T., Bedja, D., Gabrielson, K. L., Blanton, R., Siderovski, D. P., Mendelsohn, M. E., & Kass, D. A. (2009). Regulator of G protein signaling 2 mediates cardiac compensation to pressure overload and antihypertrophic effects of PDE5 inhibition in mice. Journal of Clinical Investigation, 119(2), 408-420. https://doi.org/10.1172/JCI35620