Peroxynitrite augments fMLP-stimulated chemiluminescence by neutrophils in human whole blood.
The neutrophil respiratory burst was examined by the technique of luminol-dependent chemiluminescence (LDCL) triggered by submaximal concentrations of N-formyl-methionyl-leucyl-phenylalanine (fMLP) in diluted whole blood. We sought to identify the chemical species responsible for LDCL in whole blood, to examine the role of leukotriene B4 (LTB4) and other arachidonic acid metabolites as mediators of the fMLP signaling pathway, and to investigate the effect of peroxynitrite on this response. Both sodium azide and taurine significantly inhibited LDCL (93% inhibition with 100 microM azide, 52% inhibition with 10 mM taurine). More modest inhibition was seen with superoxide dismutase (SOD), catalase, the nitric oxide synthase inhibitor monomethyl-L-arginine (L-NMMA), and with inhibitors of the cyclooxygenase (indomethacin), lipoxygenase (AA-861; no effect), and cytochrome P-450 (SKF 525-A) pathways of arachidonic acid metabolism. The nitric oxide donor SIN-1 (1-100 microM) and peroxynitrite (10-300 microM) also augmented fMLP-induced LDCL. The augmentation seen with peroxynitrite and SIN-1 was attenuated by SOD. Despite the increase in LDCL, peroxynitrite caused a dose-related inhibition of fMLP-stimulated LTB4 release. In summary, our results indicate that (1) LDCL elicited by fMLP in diluted whole blood appears primarily mediated by hypochlorous acid derived from myeloperoxidase; (2) pretreatment with the nitric oxide donor SIN-1 or with peroxynitrite augments LDCL; and (3) LTB4 release does not contribute to fMLP-stimulated LDCL or in the modulation of LDCL by SIN-1 or peroxynitrite.
Bednar
M M
MM
Division of Neurosurgery, University of Vermont, Burlington 05405-0068, USA.
Balazy
M
M
Murphy
M
M
Booth
C
C
Fuller
S P
SP
Barton
A
A
Bingham
J
J
Golding
L
L
Gross
C E
CE
D000975:Antioxidants / Q000494:pharmacology; D001386:Azides / Q000494:pharmacology; D016227:Benzoquinones / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D008163:Luminescent Measurements; D008165:Luminol; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects*; D009566:Nitrates / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D011335:Proadifen / Q000494:pharmacology; D017382:Reactive Oxygen Species; D016897:Respiratory Burst / Q000187:drug effects*; D019810:Sodium Azide; D013482:Superoxide Dismutase / Q000494:pharmacology; D013654:Taurine / Q000494:pharmacology; D019323:omega-N-Methylarginine / Q000494:pharmacology
D000975:Antioxidants; D001386:Azides; D016227:Benzoquinones; D016861:Cyclooxygenase Inhibitors; D065607:Cytochrome P-450 Enzyme Inhibitors; D016166:Free Radical Scavengers; D016859:Lipoxygenase Inhibitors; D009566:Nitrates; D017382:Reactive Oxygen Species; D013654:Taurine; C039642:peroxynitric acid; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D009240:N-Formylmethionine Leucyl-Phenylalanine; D008165:Luminol; C002385:linsidomine; C036837:2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone; D019810:Sodium Azide; D011335:Proadifen; D008981:Molsidomine; D002374:Catalase; D013482:Superoxide Dismutase