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Role of xanthine oxidoreductase and NAD(P)H oxidase in endothelial superoxide production in response to oscillatory shear stressOscillatory shear stress occurs at sites of the circulation that are vulnerable to atherosclerosis. Because oxidative stress contributes to atherosclerosis, we sought to determine whether oscillatory shear stress increases endothelial production of reactive oxygen species and to define the enzymes responsible for this phenomenon. Bovine aortic endothelial cells were exposed to static, laminar (15 dyn/cm2), and oscillatory shear stress (+/-15 dyn/cm2). Oscillatory shear increased superoxide (O2.-) production by more than threefold over static and laminar conditions as detected using electron spin resonance (ESR). This increase in O2*- was inhibited by oxypurinol and culture of endothelial cells with tungsten but not by inhibitors of other enzymatic sources. Oxypurinol also prevented H2O2 production in response to oscillatory shear stress as measured by dichlorofluorescin diacetate and Amplex Red fluorescence. Xanthine-dependent O2*- production was increased in homogenates of endothelial cells exposed to oscillatory shear stress. This was associated with decreased xanthine dehydrogenase (XDH) protein levels and enzymatic activity resulting in an elevated ratio of xanthine oxidase (XO) to XDH. We also studied endothelial cells lacking the p47phox subunit of the NAD(P)H oxidase. These cells exhibited dramatically depressed O2*- production and had minimal XO protein and activity. Transfection of these cells with p47phox restored XO protein levels. Finally, in bovine aortic endothelial cells, prolonged inhibition of the NAD(P)H oxidase with apocynin decreased XO protein levels and prevented endothelial cell stimulation of O2*- production in response to oscillatory shear stress. These data suggest that the NAD(P)H oxidase maintains endothelial cell XO levels and that XO is responsible for increased reactive oxygen species production in response to oscillatory shear stress.
Document ID
20040087544
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
McNally, J. Scott
(Emory University Atlanta, GA 30322, United States)
Davis, Michael E.
Giddens, Don P.
Saha, Aniket
Hwang, Jinah
Dikalov, Sergey
Jo, Hanjoong
Harrison, David G.
Date Acquired
August 21, 2013
Publication Date
December 1, 2003
Publication Information
Publication: American journal of physiology. Heart and circulatory physiology
Volume: 285
Issue: 6
ISSN: 0363-6135
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: HL-39006
CONTRACT_GRANT: HL-71014
CONTRACT_GRANT: HL-67413
CONTRACT_GRANT: HL-7053
CONTRACT_GRANT: PO-5800
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cell Biology
Non-NASA Center
NASA Program Fundamental Space Biology

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