Role of mitochondrial oxidant generation in endothelial cell responses to hypoxia. Arterioscler Thromb Vasc Biol 2002 Apr 01;22(4):566-73
Date
04/16/2002Pubmed ID
11950692DOI
10.1161/01.atv.0000012262.76205.6aScopus ID
2-s2.0-0036121596 (requires institutional sign-in at Scopus site) 144 CitationsAbstract
Endothelial cells increase their secretion of the cytokine interleukin-6 (IL-6) during hypoxia, which then acts in an autocrine fashion to increase the permeability of cell monolayers. These responses are attenuated by antioxidants, suggesting that reactive oxygen species (ROS) participate in signaling in hypoxic endothelium. We tested whether mitochondria are responsible for these ROS in human umbilical vein endothelial cells exposed to hypoxia. Oxidation of the probe 2', 7'-dichlorodihydrofluorescein to fluorescent dichlorofluorescein or the probe dihydroethidium was used to assess oxidant signaling, whereas permeability was assessed by using transendothelial electrical resistance. Hypoxia elicited increases in dichlorofluorescein and dihydroethidium fluorescence that were abrogated by the mitochondrial electron transport (ET) inhibitors rotenone (2 micromol/L) and diphenyleneiodonium (5 micromol/L). The same ET inhibitors also attenuated hypoxia-induced increases in nuclear factor-kappaB (NF-kappaB) activation, although they did not abrogate NF-kappaB activation in response to endotoxin (lipopolysaccharide). ET inhibition also abolished the hypoxia-induced increases in IL-6 mRNA expression, hypoxia-stimulated IL-6 secretion into the media, and the hypoxia-induced increases in transendothelial electrical resistance of human umbilical vein endothelial cell monolayers. By contrast, the above responses to hypoxia were not significantly affected by treatment with the NAD(P)H oxidase inhibitor apocynin (30 micromol/L), the xanthine oxidase inhibitor allopurinol (100 micromol/L), or the NO synthase inhibitor N-nitro-L-arginine (100 micromol/L). We conclude that ROS signals originating from the mitochondrial ET chain trigger the increase in NF-kappaB activation, the transcriptional activation of IL-6, the secretion of IL-6 into the cell culture media, and the increases in endothelial permeability observed during hypoxia.
Author List
Pearlstein DP, Ali MH, Mungai PT, Hynes KL, Gewertz BL, Schumacker PTMESH terms used to index this publication - Major topics in bold
AcetophenonesAllopurinol
Analysis of Variance
Antioxidants
Capillary Permeability
Cell Hypoxia
Cells, Cultured
Endothelium, Vascular
Enzyme Induction
Enzyme Inhibitors
Ethidium
Fluoresceins
Fluorescent Dyes
Humans
Interleukin-6
Mitochondria
NF-kappa B
Onium Compounds
Oxidation-Reduction
RNA, Messenger
Reactive Oxygen Species
Rotenone
Umbilical Veins