title: Opposing effects of Jun kinase and p38 mitogen-activated protein kinases on cardiomyocyte hypertrophy.
abstract: c-Jun N-terminal protein kinase (JNK) and p38, two distinct members of the mitogen-activated protein (MAP) kinase family, regulate gene expression in response to various extracellular stimuli, yet their physiological functions are not completely understood. In this report we show that JNK and p38 exerted opposing effects on the development of myocyte hypertrophy, which is an adaptive physiological process characterized by expression of embryonic genes and unique morphological changes. In rat neonatal ventricular myocytes, both JNK and p38 were stimulated by hypertrophic agonists like endothelin-1, phenylephrine, and leukemia inhibitory factor. Expression of MAP kinase kinase 6b (EE), a constitutive activator of p38, stimulated the expression of atrial natriuretic factor (ANF), which is a genetic marker of in vivo cardiac hypertrophy. Activation of p38 was required for ANF expression induced by the hypertrophic agonists. Furthermore, a specific p38 inhibitor, SB202190, significantly changed hypertrophic morphology induced by the agonists. Surprisingly, activation of JNK led to inhibition of ANF expression induced by MEK kinase 1 (MEKK1) and the hypertrophic agonists. MEKK1-induced ANF expression was also negatively regulated by expression of c-Jun. Our results demonstrate that p38 mediates, but JNK suppresses, the development of myocyte hypertrophy.
authors.affiliation: Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nemoto
authors.forename: Z
authors.initials: Z
authors.lastname: Sheng
authors.forename: A
authors.initials: A
authors.lastname: Lin
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D006332:Cardiomegaly / Q000201:enzymology* / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology; D019332:Endothelin-1 / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006131:Growth Inhibitors / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D015850:Interleukin-6; D048031:JNK Mitogen-Activated Protein Kinases; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases; D009206:Myocardium / Q000201:enzymology* / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D002316:Cardiotonic Agents; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D006131:Growth Inhibitors; D007093:Imidazoles; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines; D011725:Pyridines; D010656:Phenylephrine; D009320:Atrial Natriuretic Factor; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole