title: Hypoxia/reoxygenation stimulates Jun kinase activity through redox signaling in cardiac myocytes.
abstract: Hypoxia and reoxygenation are principal components of myocardial ischemia and reperfusion and have distinctive effects on the tissue. Both conditions have been associated with inflammation, necrosis, apoptosis, and myocardial infarction. Using a cell culture model of ischemia and reperfusion in which cardiac myocytes were exposed to cycles of hypoxia and reoxygenation, we report here that reoxygenation, but not hypoxia alone, caused sustained approximately 10-fold increases in phosphorylation of the amino-terminal domain of the c-jun transcription factor. The activation was similar to treatments with anisomycin or okadaic acid and correlated with the hypoxia-mediated depression of intracellular glutathione. Reoxygenation-induced c-Jun kinase activity was reduced by preincubating myocytes during the hypoxia phase with the spin-trap agent alpha-phenyl N-tert-butylnitrone or with N-acetylcysteine. The kinase activation was also inhibited by the tyrosine kinase inhibitor genistein but not by other protein kinase inhibitors. These results implicate unquenched reactive oxygen intermediates as the stimulus that initiates a kinase pathway involving the stress-activated protein kinases (JNKs/SAPKs) in reoxygenated cardiac myocytes.
authors.affiliation: Department of Cell and Molecular Biology, SRI International, Menlo Park, Calif, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Laderoute
authors.forename: K A
authors.initials: KA
authors.lastname: Webster
mesh_terms: D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D015687:Cell Hypoxia; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts; D019833:Genistein; D005978:Glutathione / Q000031:analogs & derivatives; D006321:Heart / Q000187:drug effects; D007529:Isoflavones / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D009206:Myocardium / Q000201:enzymology*; D019319:Okadaic Acid / Q000494:pharmacology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D017382:Reactive Oxygen Species / Q000502:physiology; D013997:Time Factors
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D007529:Isoflavones; D011500:Protein Synthesis Inhibitors; D017382:Reactive Oxygen Species; D019319:Okadaic Acid; D019328:Buthionine Sulfoximine; D000841:Anisomycin; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D005978:Glutathione; D010100:Oxygen