Hyperoxia-induced NAD(P)H oxidase activation and regulation by MAP kinases in human lung endothelial cells

Abstract

Hyperoxia increases reactive oxygen species (ROS) production in vascular endothelium; however, the mechanisms involved in ROS generation are not well characterized. We determined the role and regulation of NAD(P)H oxidase in hyperoxia-induced ROS formation in human pulmonary artery endothelial cells (HPAECs). Exposure of HPAECs to hyperoxia for 1, 3, and 12 h increased the generation of superoxide anion, which was blocked by diphenyleneiodonium but not by rotenone or oxypurinol. Furthermore, hyperoxia enhanced NADPH- and NADH-dependent and superoxide dismutase- or diphenyleneiodonium-inhibitable ROS production in HPAECs. Immunohistocytochemistry and Western blotting revealed the presence of gp91, p67 phox, p22 phox, and p47 phox subcomponents of NADPH oxidase in HPAECs. Transfection of HPAECs with p22 phox antisense plasmid inhibited hyperoxia-induced ROS production. Exposure of HPAECs to hyperoxia activated p38 MAPK and ERK, and inhibition of p38 MAPK and MEK1/2 attenuated the hyperoxia-induced ROS generation. These results suggest a role for MAPK in regulating hyperoxia-induced NAD(P)H oxidase activation in HPAECs.

Human 8-oxoguanine DNA glycosylase increases resistance to hyperoxic cytotoxicity in lung epithelial cells and involvement with altered MAPK activity

“…Although previous studies demonstrated that p38 activity is associated with nitrogen oxide and other oxidants, 22,25,44 no direct evidence has shown a particular link of p38 to hyperoxic toxicity in lung epithelial cells. In this study, cells expressing hOgg1 or vector control were exposed to room air or hyperoxia for 36 h. Phosphorylated p38 was quantitatively measured using phospho-ATF-2 Thr71 antibody in A549 cells after immunoprecipitation with immobilized phospho-p38 antibodies (Thr180/Tyr182).…”

Chlorotyrosine promotes human aortic smooth muscle cell migration through increasing superoxide anion production and ERK1/2 activation

“…The effect of oxidative stress on endothelial cells and VSMC include direct oxidation of proteins and indirect modulation of kinase pathways such as PKC, ERK, Src, and Pho [9]. Many factors such as cytokine, drugs, and extracellular inflammation factors could increase ROS generation to regulate cellular reactions including cell proliferation and migration [10].…”

“…Since the activation of MAPKs can be triggered by oxidative stress [9] and chlorotyrosine can increase superoxide anion production in this study, we further investigated whether chlorotyrosine could activate MAPKs. Major MAPKs include ERK1/2, and the c-Jun Nterminal protein kinase (JNK), and p38.…”

“…Reactive oxygen species (ROS) including superoxide anion are generated by a variety of extracellular and intracellular mechanisms and are involved in several signal transduction pathways such as mitogen-activated protein kinases (MAPKs) [9]. ROS mediate cellular signaling pathways in VSMC proliferation and migration associated with atherosclerosis [10].…”

NADPH oxidases in lung biology and pathology: Host defense enzymes, and more

“…These NOX's appear to control several vascular processes, such as vascular tone, vascular cell growth and angiogenesis, and inflammation. Accordingly, pulmonary endothelial cells have been demonstrated to generate NADPH-derived oxidants in response to pulmonary ischemia (178,179) as well as hyperoxia (180), which is associated with membrane depolarization due to the activation of K(ATP) channels, and resulting in stimulated endothelial cell proliferation and NO production (178,181,182). Although these responses were in some cases inhibited by catalase, suggesting the involvement of H 2 O 2 (182), recent studies also suggest a role for O 2 •− in endothelial NOX signaling (77).…”