title: Inhibition of calcineurin-NFAT hypertrophy signaling by cGMP-dependent protein kinase type I in cardiac myocytes.
abstract: Recent investigation has focused on identifying signaling pathways that inhibit cardiac hypertrophy, a major risk factor for cardiovascular morbidity and mortality. In this context, nitric oxide (NO), signaling via cGMP and cGMP-dependent protein kinase type I (PKG I), has been recognized as a negative regulator of cardiac myocyte (CM) hypertrophy. However, the underlying mechanisms are poorly understood. Here, we show that PKG I inhibits CM hypertrophy by targeting the calcineurin-NFAT signaling pathway. Calcineurin, a Ca2+-dependent phosphatase, promotes hypertrophy in part by activating NFAT transcription factors which induce expression of hypertrophic genes, including brain natriuretic peptide (BNP). Activation of PKG I by NO/cGMP in CM suppressed NFAT transcriptional activity, BNP induction, and cell enlargement in response to alpha(1)-adrenoreceptor stimulation but not in response to adenoviral expression of a Ca2+-independent, constitutively active calcineurin mutant, thus demonstrating NO-cGMP-PKG I inhibition of calcineurin-NFAT signaling upstream of calcineurin. PKG I suppressed single L-type Ca2+-channel open probability, [Ca2+]i transient amplitude, and, most importantly, L-type Ca2+-channel current-induced NFAT activation, indicating that PKG I targets Ca2+-dependent steps upstream of calcineurin. Adenoviral expression of PKG I enhanced NO/cGMP inhibitory effects upstream of calcineurin, confirming that PKG I mediates NO/cGMP inhibition of calcineurin-NFAT signaling. In CM overexpressing PKG I, NO/cGMP also suppressed BNP induction and cell enlargement but not NFAT activation elicited by constitutively active calcineurin, which is consistent with additional, NFAT-independent inhibitory effect(s) of PKG I downstream of calcineurin. Inhibition of calcineurin-NFAT signaling by PKG I provides a framework for understanding how NO inhibits cardiac myocyte hypertrophy.
authors.affiliation: Department of Cardiology and Angiology, Hannover Medical School, 30625 Hannover, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Fiedler
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Lohmann
authors.forename: Albert
authors.initials: A
authors.lastname: Smolenski
authors.forename: Stephan
authors.initials: S
authors.lastname: Linnemuller
authors.forename: Burkert
authors.initials: B
authors.lastname: Pieske
authors.forename: Frank
authors.initials: F
authors.lastname: Schroder
authors.forename: Jeffery D
authors.initials: JD
authors.lastname: Molkentin
authors.forename: Helmut
authors.initials: H
authors.lastname: Drexler
authors.forename: Kai C
authors.initials: KC
authors.lastname: Wollert
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D019703:Calcineurin / Q000502:physiology*; D065095:Calcineurin Inhibitors; D020746:Calcium Channels, L-Type / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology; D006332:Cardiomegaly / Q000201:enzymology / Q000503:physiopathology* / Q000517:prevention & control*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D004789:Enzyme Activation; D006321:Heart / Q000502:physiology; D006352:Heart Ventricles; D015640:Ion Channel Gating / Q000502:physiology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D050778:NFATC Transcription Factors; D020097:Natriuretic Peptide, Brain / Q000235:genetics; D009687:Nuclear Proteins; D010957:Plasmids; D011336:Probability; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D065095:Calcineurin Inhibitors; D020746:Calcium Channels, L-Type; D004268:DNA-Binding Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D013873:Thionucleotides; D014157:Transcription Factors; D020097:Natriuretic Peptide, Brain; C055656:8-((4-chlorophenyl)thio)cyclic-3',5'-GMP; D008156:Luciferases; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; D019703:Calcineurin; D006152:Cyclic GMP