title: Regulation of cardiotrophin-1 expression in mouse embryonic stem cells by HIF-1alpha and intracellular reactive oxygen species.
abstract: Cardiomyogenesis in differentiating mouse embryonic stem (ES) cells is promoted by cardiotrophin-1 (CT-1), a member of the IL-6 interleukin superfamily that acts through the tall gp130 cytokine receptor. We show that prooxidants (menadione, hydrogen peroxide) as well as chemical (CoCl2) and physiological (1% O2) hypoxia increased CT-1 as well as HIF-1alpha protein and mRNA expression in embryoid bodies, indicating that CT-1 expression is regulated by reactive oxygen species (ROS) and hypoxia. Treatment with either prooxidants or chemical hypoxia increased gp130 phosphorylation and protein expression of NADPH oxidase subunits p22-phox, p47-phox, p67-phox, as well as Nox1 and Nox4 mRNA. Consequently, inhibition of NADPH oxidase activity by diphenylen iodonium chloride (DPI) and apocynin abolished prooxidant- and chemical hypoxia-induced upregulation of CT-1. Prooxidants and chemical hypoxia activated ERK1,2, JNK and p38 as well as PI3-kinase. The proxidant- and CoCl2-mediated upregulation of CT-1 was significantly inhibited in the presence of the ERK1,2 antagonist UO126, the JNK antagonist SP600125, the p38 antagonist SKF86002, the PI3-kinase antagonist LY294002, the Jak-2 antagonist AG490 as well as in the presence of free radical scavengers. Moreover, developing embryoid bodies derived from HIF-1alpha-/- ES cells lack cardiomyogenesis, and prooxidants as well as chemical hypoxia failed to upregulate CT-1 expression. Our results demonstrate that CT-1 expression in ES cells is regulated by ROS and HIF-1alpha and imply a crucial role of CT-1 in the survival and proliferation of ES-cell-derived cardiac cells.
authors.affiliation: Department of Physiology, University of Giessen, 35392 Giessen, Germany.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Ateghang
authors.forename: Maria
authors.initials: M
authors.lastname: Wartenberg
authors.forename: Max
authors.initials: M
authors.lastname: Gassmann
authors.forename: Heinrich
authors.initials: H
authors.lastname: Sauer
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects; D050822:Cytokine Receptor gp130 / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D032383:Myocytes, Cardiac / Q000502:physiology; D000074624:NADPH Oxidase 1; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013234:Stem Cells / Q000502:physiology*; D024483:Vitamin K 3 / Q000494:pharmacology
chemical_list: D016207:Cytokines; D004791:Enzyme Inhibitors; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016877:Oxidants; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; C079789:neutrophil cytosol factor 67K; D050822:Cytokine Receptor gp130; D024483:Vitamin K 3; C092073:cardiotrophin 1; D006861:Hydrogen Peroxide; D000074624:NADPH Oxidase 1; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C402799:NOX1 protein, human; C498910:NOX4 protein, human; C086986:CYBA protein, human; C060505:neutrophil cytosolic factor 1