title: Activation of NF-kappa B is required for hypertrophic growth of primary rat neonatal ventricular cardiomyocytes.
abstract: The transcription factor NF-kappaB regulates expression of genes that are involved in inflammation, immune response, viral infection, cell survival, and division. However, the role of NF-kappaB in hypertrophic growth of terminally differentiated cardiomyocytes is unknown. Here we report that NF-kappaB activation is required for hypertrophic growth of cardiomyocytes. In cultured rat primary neonatal ventricular cardiomyocytes, the nuclear translocation of NF-kappaB and its transcriptional activity were stimulated by several hypertrophic agonists, including phenylephrine, endothelin-1, and angiotensin II. The activation of NF-kappaB was inhibited by expression of a "supersuppressor" IkappaBalpha mutant that is resistant to stimulation-induced degradation and a dominant negative IkappaB kinase (IKKbeta) mutant that can no longer be activated by phosphorylation. Furthermore, treatment with phenylephrine induced IkappaBalpha degradation in an IKK-dependent manner, suggesting that NF-kappaB is a downstream target of the hypertrophic agonists. Importantly, expression of the supersuppressor IkappaBalpha mutant or the dominant negative IKKbeta mutant blocked the hypertrophic agonist-induced expression of the embryonic gene atrial natriuretic factor and enlargement of cardiomyocytes. Conversely, overexpression of NF-kappaB itself induced atrial natriuretic factor expression and cardiomyocyte enlargement. These findings suggest that NF-kappaB plays a critical role in the hypertrophic growth of cardiomyocytes and may serve as a potential target for the intervention of heart disease.
authors.affiliation: Ben May Institute for Cancer Research and the Committee on Cancer Biology, University of Chicago, 5841 South Maryland Avenue, MC6027, Chicago, IL 60637, USA.
authors.forename: N H
authors.initials: NH
authors.lastname: Purcell
authors.forename: G
authors.initials: G
authors.lastname: Tang
authors.forename: C
authors.initials: C
authors.lastname: Yu
authors.forename: F
authors.initials: F
authors.lastname: Mercurio
authors.forename: J A
authors.initials: JA
authors.lastname: DiDonato
authors.forename: A
authors.initials: A
authors.lastname: Lin
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000235:genetics; D006332:Cardiomegaly / Q000209:etiology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D020672:I-kappa B Proteins; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; D000804:Angiotensin II; D000072000:NF-KappaB Inhibitor alpha; D010656:Phenylephrine; D009320:Atrial Natriuretic Factor