Protein kinase C-alpha-induced hypertrophy of neonatal rat ventricular myocytes.
Protein kinase C (PKC) isoenzymes play a critical role in cardiomyocyte hypertrophy. At least three different phorbol ester-sensitive PKC isoenzymes are expressed in neonatal rat ventricular myocytes (NRVMs): PKC-alpha, -delta, and -epsilon. Using replication-defective adenoviruses (AdVs) that express wild-type (WT) and dominant-negative (DN) PKC-alpha together with phorbol myristate acetate (PMA), which is a hypertrophic agonist and activator of all three PKC isoenzymes, we studied the role of PKC-alpha in signaling-specific aspects of the hypertrophic phenotype. PMA induced nuclear translocation of endogenous and AdV-WT PKC-alpha in NRVMs. WT PKC-alpha overexpression increased protein synthesis and the protein-to-DNA (P/D) ratio but did not affect cell surface area (CSA) or cell shape compared with uninfected or control AdV beta-galactosidase (AdV betagal)-infected cells. PMA-treated uninfected cells displayed increased protein synthesis, P/D ratio, and CSA and elongated morphology. PMA did not further enhance protein synthesis or P/D ratio in AdV-WT PKC-alpha-infected cells. To assess the requirement of PKC-alpha for these PMA-induced changes, AdV-DN PKC-alpha or AdV betagal-infected NRVMs were stimulated with PMA. Without PMA, AdV-DN PKC-alpha had no effects on protein synthesis, P/D ratio, CSA, or shape vs. AdV betagal-infected NRVMs. PMA increased protein synthesis, P/D ratio, and CSA in AdV betagal-infected cells, but these parameters were significantly reduced in PMA-stimulated AdV-DN PKC-alpha-infected NRVMs. Overexpression of DN PKC-alpha enhanced PMA-induced cell elongation. Neither WT PKC-alpha nor DN PKC-alpha affected atrial natriuretic factor gene expression. Insulin-like growth factor-1 also induced nuclear translocation of endogenous PKC-alpha. PMA but not WT PKC-alpha overexpression induced ERK1/2 activation. However, AdV-DN PKC-alpha partially blocked PMA-induced ERK activation. Thus PKC-alpha is necessary for certain aspects of PMA-induced NRVM hypertrophy.
Cardiovascular Institute, Loyola Univ. Medical Center, Bldg. 110, Rm. 5232, 2160 S. First Ave., Maywood, IL 60153, USA. kvijaya@lumc.edu
Kalpana
K
Vijayan
Erika L
EL
Szotek
Jody L
JL
Martin
Allen M
AM
Samarel
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000222:Adaptation, Physiological / Q000502:physiology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies; D002273:Carcinogens / Q000494:pharmacology; D002478:Cells, Cultured; D015971:Gene Expression Regulation, Enzymologic; D006352:Heart Ventricles / Q000166:cytology; D006984:Hypertrophy; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000201:enzymology*; D011493:Protein Kinase C / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000906:Antibodies; D002273:Carcinogens; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; C497260:Prkcd protein, rat; C497257:Prkce protein, rat; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D013755:Tetradecanoylphorbol Acetate