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Stress-dependent dilated cardiomyopathy in mice with cardiomyocyte-restricted inactivation of cyclic GMP-dependent protein kinase I.

Abstract：

AIMS:Cardiac hypertrophy is a common and often lethal complication of arterial hypertension. Elevation of myocyte cyclic GMP levels by local actions of endogenous atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) or by pharmacological inhibition of phosphodiesterase-5 was shown to counter-regulate pathological hypertrophy. It was suggested that cGMP-dependent protein kinase I (cGKI) mediates this protective effect, although the role in vivo is under debate. Here, we investigated whether cGKI modulates myocyte growth and/or function in the intact organism. METHODS AND RESULTS:To circumvent the systemic phenotype associated with germline ablation of cGKI, we inactivated the murine cGKI gene selectively in cardiomyocytes by Cre/loxP-mediated recombination. Mice with cardiomyocyte-restricted cGKI deletion exhibited unaltered cardiac morphology and function under resting conditions. Also, cardiac hypertrophic and contractile responses to β-adrenoreceptor stimulation by isoprenaline (at 40 mg/kg/day during 1 week) were unaltered. However, angiotensin II (Ang II, at 1000 ng/kg/min for 2 weeks) or transverse aortic constriction (for 3 weeks) provoked dilated cardiomyopathy with marked deterioration of cardiac function. This was accompanied by diminished expression of the [Ca(2+)]i-regulating proteins SERCA2a and phospholamban (PLB) and a reduction in PLB phosphorylation at Ser16, the specific target site for cGKI, resulting in altered myocyte Ca(2+)i homeostasis. In isolated adult myocytes, CNP, but not ANP, stimulated PLB phosphorylation, Ca(2+)i-handling, and contractility via cGKI. CONCLUSION:These results indicate that the loss of cGKI in cardiac myocytes compromises the hypertrophic program to pathological stimulation, rendering the heart more susceptible to dysfunction. In particular, cGKI mediates stimulatory effects of CNP on myocyte Ca(2+)i handling and contractility.

journal_name

Eur Heart J

journal_title

European heart journal

authors

Frantz S,Klaiber M,Baba HA,Oberwinkler H,Völker K,Gaβner B,Bayer B,Abeβer M,Schuh K,Feil R,Hofmann F,Kuhn M

doi

10.1093/eurheartj/ehr445

subject

Has Abstract

pub_date

2013-04-01 00:00:00

pages

1233-44

issue

eissn

0195-668X

issn

1522-9645

pii

ehr445

journal_volume

pub_type

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Stress-dependent dilated cardiomyopathy in mice with cardiomyocyte-restricted inactivation of cyclic GMP-dependent protein kinase I.