title: MAP kinase kinase 6-p38 MAP kinase signaling cascade regulates cyclooxygenase-2 expression in cardiac myocytes in vitro and in vivo.
abstract: Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in delayed prostaglandin biosynthesis. The purpose of this study was to evaluate the role of the MAP kinase kinase 6 (MKK6)-p38 MAPK signaling cascade in the regulation of myocardial COX-2 gene expression, in vitro and in vivo. RT-PCR analysis identified p38alpha and p38beta2 MAPK mRNA in rat cardiac myocytes. Interleukin-1beta induced the phosphorylation of p38alpha and p38beta2 MAPK in cardiomyocytes and stimulated RNA polymerase II binding to the COX-2 promoter, COX-2 transcription, COX-2 protein synthesis, and prostaglandin E2 (PGE2) release. Infecting cardiomyocytes with adenoviruses that encode mutant, phosphorylation-resistant MKK6 or p38beta2 MAPK inhibited interleukin-1beta-induced p38 MAPK activation, COX-2 gene expression, and PGE2 release. Treatment with the p38alpha and p38beta2 MAPK inhibitor, SB202190, attenuated interleukin-1beta-induced COX-2 transcription and accelerated the degradation of COX-2 mRNA. Cells infected with adenoviruses encoding wild-type or constitutively activated MKK6 or p38beta2 MAPK, in the absence of interleukin-1beta, exhibited increased cellular p38 MAPK activity, COX-2 mRNA expression, and COX-2 protein synthesis, which was blocked by SB202190. In addition, elevated levels of COX-2 protein were identified in the hearts of transgenic mice with cardiac-restricted expression of wild-type or constitutively activated MKK6, in comparison with nontransgenic littermates. These results provide direct evidence that MKK6 mediated p38 MAPK activation is necessary for interleukin-1beta-induced cardiac myocyte COX-2 gene expression and PGE2 biosynthesis in vitro and is sufficient for COX-2 gene expression by cardiac myocytes in vitro and in vivo.
authors.affiliation: Division of Vascular Surgery, 200 Elizabeth St, EC5-302a, Toronto General Hospital, Toronto, Ontario, Canada M5G-2C4.
authors.forename: Norbert
authors.initials: N
authors.lastname: Degousee
authors.forename: Joshua
authors.initials: J
authors.lastname: Martindale
authors.forename: Eva
authors.initials: E
authors.lastname: Stefanski
authors.forename: Martin
authors.initials: M
authors.lastname: Cieslak
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Lindsay
authors.forename: Jason E
authors.initials: JE
authors.lastname: Fish
authors.forename: Philip A
authors.initials: PA
authors.lastname: Marsden
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Thuerauf
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Glembotski
authors.forename: Barry B
authors.initials: BB
authors.lastname: Rubin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000831:Animals, Newborn; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006352:Heart Ventricles / Q000166:cytology / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D048669:MAP Kinase Kinase 6; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014404:Tubulin / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D007375:Interleukin-1; D007527:Isoenzymes; D011725:Pyridines; D012333:RNA, Messenger; D014404:Tubulin; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048669:MAP Kinase Kinase 6; D015232:Dinoprostone; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole