Chen Jian-Xiong, Zeng Heng, Tuo Qin-Hui, Yu Heidi, Meyrick Barbara, Aschner Judy L
Department of Pediatrics, Division of Neonatology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA.
Am J Physiol Heart Circ Physiol. 2007 Apr;292(4):H1664-74. doi: 10.1152/ajpheart.01138.2006. Epub 2007 Jan 12.
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.
近期研究表明，活性氧（ROS）通过丝裂原活化蛋白激酶和丝氨酸 - 苏氨酸激酶Akt/蛋白激酶B信号通路介导心肌缺血再灌注（I/R）及血管生成。NADPH氧化酶是内皮细胞和心肌细胞中ROS的主要来源。在本研究中，我们使用猪冠状动脉内皮细胞（PCAECs）和小鼠心肌I/R模型，研究了NADPH氧化酶衍生的ROS在缺氧复氧（H/R）诱导的Akt和ERK1/2激活及血管生成中的作用。我们的数据表明，PCAECs缺氧2小时后再复氧1小时可显著增加ROS的生成。用NADPH氧化酶抑制剂二苯基碘鎓（DPI，10微摩尔）和白杨素（Apo，200和600微摩尔）预处理可显著减弱H/R诱导的ROS生成。此外，PCAECs暴露于H/R会导致Akt和ERK1/2激活显著增加。PCAEC球体和小鼠主动脉环暴露于H/R会显著增加内皮球体发芽和血管生长，而NADPH氧化酶的药理学抑制或NADPH氧化酶亚基p47（phox）（p47（phox-/-））的基因缺失则显著抑制了这些变化。使用小鼠I/R模型，我们的数据进一步表明，与野生型小鼠相比，p47（phox-/-）小鼠在经历心肌I/R时，心肌Akt和ERK1/2激活以及血管内皮生长因子（VEGF）表达的增加明显减弱。我们的研究结果强调了NADPH氧化酶及其亚基p47（phox）在调节经历I/R的心肌中的Akt和ERK1/2激活、血管生成生长因子表达及血管生成中的重要作用。
