title: NADPH oxidase modulates myocardial Akt, ERK1/2 activation, and angiogenesis after hypoxia-reoxygenation.
abstract: Recent studies have demonstrated that reactive oxygen species (ROS) mediate myocardial ischemia-reperfusion (I/R) and angiogenesis via the mitogen-activated protein kinases and the serine-threonine kinase Akt/protein kinase B pathways. NADPH oxidases are major sources of ROS in endothelial cells and cardiomyocytes. In the present study, we investigated the role of NADPH oxidase-derived ROS in hypoxia-reoxygenation (H/R)-induced Akt and ERK1/2 activation and angiogenesis using porcine coronary artery endothelial cells (PCAECs) and a mouse myocardial I/R model. Our data demonstrate that exposure of PCAECs to hypoxia for 2 h followed by 1 h of reoxygenation significantly increased ROS formation. Pretreatment with the NADPH oxidase inhibitors, diphenyleneiodonium (DPI, 10 microM) and apocynin (Apo, 200 and 600 microM), significantly attenuated H/R-induced ROS formation. Furthermore, exposure of PCAECs to H/R caused a significant increase in Akt and ERK1/2 activation. Exposure of PCAEC spheroids and mouse aortic rings to H/R significantly increased endothelial spheroid sprouting and vessel outgrowth, whereas pharmacological inhibition of NADPH oxidase or genetic deletion of the NADPH oxidase subunit, p47(phox) (p47(phox-/-)), significantly suppressed these changes. With the use of a mouse I/R model, our data further show that the increases in myocardial Akt and ERK1/2 activation and vascular endothelial growth factor (VEGF) expression were markedly blunted in the p47(phox-/-) mouse subjected to myocardial I/R compared with the wild-type mouse. Our findings underscore the important role of NADPH oxidase and its subunit p47(phox) in modulating Akt and ERK1/2 activation, angiogenic growth factor expression, and angiogenesis in myocardium undergoing I/R.
authors.affiliation: Department of Pediatrics, Division of Neonatology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA. jian-xiong.chen@vanderbilt.edu
authors.forename: Jian-Xiong
authors.initials: JX
authors.lastname: Chen
authors.forename: Heng
authors.initials: H
authors.lastname: Zeng
authors.forename: Qin-Hui
authors.initials: QH
authors.lastname: Tuo
authors.forename: Heidi
authors.initials: H
authors.lastname: Yu
authors.forename: Barbara
authors.initials: B
authors.lastname: Meyrick
authors.forename: Judy L
authors.initials: JL
authors.lastname: Aschner
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003094:Collagen; D003331:Coronary Vessels / Q000166:cytology / Q000201:enzymology*; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D005782:Gels; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D020935:MAP Kinase Signaling System / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D017202:Myocardial Ischemia / Q000378:metabolism / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000503:physiopathology; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018874:Spheroids, Cellular; D013481:Superoxides / Q000378:metabolism; D013552:Swine
chemical_list: D005782:Gels; D017382:Reactive Oxygen Species; D013481:Superoxides; D003094:Collagen; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3