Autonomous and growth factor-induced hypertrophy in cultured neonatal mouse cardiac myocytes. Comparison with rat.
Cultured neonatal rat cardiac myocytes have been used extensively to study cellular and molecular mechanisms of cardiac hypertrophy. However, there are only a few studies in cultured mouse myocytes despite the increasing use of genetically engineered mouse models of cardiac hypertrophy. Therefore, we characterized hypertrophic responses in low-density, serum-free cultures of neonatal mouse cardiac myocytes and compared them with rat myocytes. In mouse myocyte cultures, triiodothyronine (T3), norepinephrine (NE) through a beta-adrenergic receptor, and leukemia inhibitory factor induced hypertrophy by a 20% to 30% increase in [(3)H]phenylalanine-labeled protein content. T3 and NE also increased alpha-myosin heavy chain (MyHC) mRNA and reduced beta-MyHC. In contrast, hypertrophic stimuli in rat myocytes, including alpha(1)-adrenergic agonists, endothelin-1, prostaglandin F(2alpha), interleukin 1beta, and phorbol 12-myristate 13-acetate (PMA), had no effect on mouse myocyte protein content. In further contrast with the rat, none of these agents increased atrial natriuretic factor or beta-MyHC mRNAs. Acute PMA signaling was intact by extracellular signal-regulated kinase (ERK1/2) and immediate-early gene (fos/jun) activation. Remarkably, mouse but not rat myocytes had hypertrophy in the absence of added growth factors, with increases in cell area, protein content, and the mRNAs for atrial natriuretic factor and beta-MyHC. We conclude that mouse myocytes have a unique autonomous hypertrophy. On this background, T3, NE, and leukemia inhibitory factor activate hypertrophy with different mRNA phenotypes, but certain Gq- and protein kinase C-coupled agonists do not.
Deng
X F
XF
VA Medical Center and the Cardiovascular Research Institute and Department of Medicine, University of California, San Francisco, California, USA.
Rokosh
D G
DG
Simpson
P C
PC
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D015237:Dinoprost / Q000494:pharmacology; D019332:Endothelin-1 / Q000494:pharmacology; D005333:Fetus; D006131:Growth Inhibitors / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects* / Q000196:embryology; D006984:Hypertrophy; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000494:pharmacology; D051379:Mice; D008858:Microscopy, Phase-Contrast; D023421:Models, Animal; D009206:Myocardium / Q000473:pathology*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D009218:Myosins / Q000032:analysis; D009638:Norepinephrine / Q000494:pharmacology; D010641:Phenotype; D010649:Phenylalanine / Q000032:analysis; D014176:Protein Biosynthesis; D011506:Proteins / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D019332:Endothelin-1; D006131:Growth Inhibitors; D006133:Growth Substances; D007375:Interleukin-1; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D008222:Lymphokines; D011506:Proteins; D012333:RNA, Messenger; D014284:Triiodothyronine; D010649:Phenylalanine; D009320:Atrial Natriuretic Factor; D015237:Dinoprost; D018995:Myosin Heavy Chains; D009218:Myosins; D013755:Tetradecanoylphorbol Acetate; D009638:Norepinephrine