Characterization of nitric oxide consumption pathways by normal, chronic granulomatous disease and myeloperoxidase-deficient human neutrophils.
The detailed mechanisms by which acutely activated leukocytes metabolize NO and regulate its bioactivity are unknown. Therefore, healthy, chronic granulomatous disease (CGD) or myeloperoxidase (MPO)-deficient human neutrophils were examined for their ability to consume NO and attenuate its signaling. fMLP or PMA activation of healthy neutrophils caused NO consumption that was fully blocked by NADPH oxidase inhibition, and was absent in CGD neutrophils. Studies using MPO-deficient neutrophils, enzyme inhibitors, and reconstituted NADPH oxidase ruled out additional potential NO-consuming pathways, including Fenton chemistry, PGH synthase, lipoxygenase, or MPO. In particular, the inability of MPO to consume NO resulted from lack of H(2)O(2) substrate since all superoxide (O(2)(-.) reacted to form peroxynitrite. For healthy or MPO-deficient cells, NO consumption rates were 2- to 4-fold greater than O(2)(-.) generation, significantly faster than expected from 1:1 termination of NO with O(2)(-.). Finally, fMLP or PMA-stimulated NO consumption fully blocked NO-dependent neutrophil cGMP synthesis. These data reveal NADPH oxidase as the central regulator of NO signaling in human leukocytes. In addition, they demonstrate an important functional difference between CGD and either normal or MPO-deficient human neutrophils, namely their inability to metabolize NO which will alter their ability to adhere and migrate in vivo.
Clark
Stephen R
SR
Department of Medical Biochemistry and Immunology, University of Wales College of Medicine, Cardiff, Wales, United Kingdom.
Coffey
Marcus J
MJ
Maclean
Rhona M
RM
Collins
Peter W
PW
Lewis
Malcolm J
MJ
Cross
Andrew R
AR
O'Donnell
Valerie B
VB
D000640:Amitrole / Q000494:pharmacology; D004563:Electrochemistry; D004566:Electrodes; D004789:Enzyme Activation / Q000502:physiology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006105:Granulomatous Disease, Chronic / Q000378:metabolism* / Q000473:pathology; D006162:Guanylate Cyclase; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D007700:Kinetics; D008954:Models, Biological; D008956:Models, Chemical; D019255:NADPH Oxidases / Q000378:metabolism / Q000502:physiology; D018375:Neutrophil Activation / Q000502:physiology; D009504:Neutrophils / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology*; D004369:Pentetic Acid / Q000494:pharmacology; D009195:Peroxidase / Q000097:blood / Q000172:deficiency* / Q000502:physiology; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D013481:Superoxides / Q000378:metabolism
D016166:Free Radical Scavengers; D018160:Receptors, Cytoplasmic and Nuclear; D013481:Superoxides; D009569:Nitric Oxide; D004369:Pentetic Acid; D009195:Peroxidase; D019255:NADPH Oxidases; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D007213:Indomethacin; D000640:Amitrole