title: Reactive oxygen intermediates induce monocyte chemotactic protein-1 in vascular endothelium after brief ischemia.
abstract: Chemokine expression is associated with reperfusion of infarcted myocardium in the setting of tissue necrosis, intense inflammation, and inflammatory cytokine release. The specific synthesis of monocyte chemotactic protein (MCP)-1 mRNA by cardiac venules in reperfused infarcts corresponded to the region where leukocytes normally localize. MCP-1 could be induced by exogenous tumor necrosis factor (TNF)-alpha or by postischemic cardiac lymph containing TNF-alpha. However, the release of TNF-alpha during early reperfusion did not explain the venular localization of MCP-1 induction. To better understand the factors mediating MCP-1 induction, we examined the role of ischemia/reperfusion in a model of brief coronary occlusion in which no necrosis or inflammatory response is seen. Adult mongrel dogs were subjected to 15 minutes of coronary occlusion and 5 hours of reperfusion. Ribonuclease protection assay revealed up-regulation of MCP-1 mRNA only in ischemic segments of reperfused canine myocardium. Pretreatment with the reactive oxygen scavenger N-(2-mercaptopropionyl)-glycine completely inhibited MCP-1 induction. In situ hybridization localized MCP-1 message to small venular endothelium in ischemic areas without myocyte necrosis. Gel shift analysis of nuclear extracts from the ischemic area showed enhanced DNA binding of the transcription factors AP-1 and nuclear factor (NF)-kappaB, crucial for MCP-1 expression, in ischemic myocardial regions. Immunohistochemical staining demonstrated reperfusion-dependent nuclear translocation of c-Jun and NF-kappaB (p65) in small venular endothelium, only in the ischemic regions of the myocardium, that was inhibited by N-(2-mercaptopropionyl)-glycine. In vitro, treatment of cultured canine jugular vein endothelial cells with the reactive oxygen intermediate H2O2 induced a concentration-dependent increase in MCP-1 mRNA levels, which was inhibited by the antioxidant N-acetyl-L-cysteine, a precursor of glutathione, but not pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB and activator of AP-1. In contrast to our studies with infarction, incubation of canine jugular vein endothelial cells with postischemic cardiac lymph did not induce MCP-1 mRNA expression suggesting the absence of cytokine-mediated MCP-1 induction after a sublethal ischemic period. These results suggest that reactive oxygen intermediate generation, after a brief ischemic episode, is capable of inducing MCP-1 expression in venular endothelium through AP-1 and NF-kappaB. Short periods of ischemia/reperfusion, insufficient to produce a myocardial infarction, induce MCP-1 expression, potentially mediating angiogenesis in the ischemic noninfarcted heart.
authors.affiliation: Department of Medicine, Section of Cardiovascular Sciences and Cardiology, the DeBakey Heart Center, Baylor College of Medicine Houston, and the Methodist Hospital, Houston, Texas 77030-3498, USA.
authors.forename: V
authors.initials: V
authors.lastname: Lakshminarayanan
authors.forename: M
authors.initials: M
authors.lastname: Lewallen
authors.forename: N G
authors.initials: NG
authors.lastname: Frangogiannis
authors.forename: A J
authors.initials: AJ
authors.lastname: Evans
authors.forename: K E
authors.initials: KE
authors.lastname: Wedin
authors.forename: L H
authors.initials: LH
authors.lastname: Michael
authors.forename: M L
authors.initials: ML
authors.lastname: Entman
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000502:physiology*; D013859:Thiocarbamates / Q000494:pharmacology; D014018:Tissue Distribution; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014699:Venules / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D016166:Free Radical Scavengers; D016328:NF-kappa B; D016877:Oxidants; D011759:Pyrrolidines; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D013859:Thiocarbamates; D018808:Transcription Factor AP-1; C020972:pyrrolidine dithiocarbamic acid; D006861:Hydrogen Peroxide; D000111:Acetylcysteine