ROLE OF ARACHIDONIC-ACID AND ITS METABOLITES IN THE PRIMING OF NADPH OXIDASE IN HUMAN POLYMORPHONUCLEAR LEUKOCYTES BY PERITONEAL-DIALYSIS EFFLUENT

Citation
I. Daniels et al., ROLE OF ARACHIDONIC-ACID AND ITS METABOLITES IN THE PRIMING OF NADPH OXIDASE IN HUMAN POLYMORPHONUCLEAR LEUKOCYTES BY PERITONEAL-DIALYSIS EFFLUENT, Clinical and diagnostic laboratory immunology, 5(5), 1998, pp. 683-689
Citations number
52
Categorie Soggetti
Immunology,"Infectious Diseases",Microbiology
ISSN journal
1071412X
Volume
5
Issue
5
Year of publication
1998
Pages
683 - 689
Database
ISI
SICI code
1071-412X(1998)5:5<683:ROAAIM>2.0.ZU;2-S
Abstract
Peritoneal dialysis effluent (PDE) contains a low-molecular-weight sol ute that will activate and prime the NADPH oxidase of human neutrophil s via a phospholipase A(2) (PLA(2))-dependent mechanism. Since the pro ducts of PLA(2) are known to activate and prime the oxidase we have in vestigated their role in the dialysis effluent-mediated activation and priming of human neutrophils. NADPH oxidase activity of PDE-primed an d -unprimed neutrophils was measured by lucigenin-enhanced chemilumine scence in the presence of known inhibitors of the arachidonic acid cas cade. Incubation of neutrophils with the nonselective PLA(2) inhibitor quinacrine (0 to 100 mu M) reduced oxidase activity in both primed an d unprimed cells. Furthermore, primed cells were more sensitive to the action of quinacrine than were unprimed cells, We were unable to dete rmine the relative roles of secretory PLA(2) (sPLA(2)) and cytosolic P LA(2) (cPLA(2)) since the selective sPLA(2) inhibitor scalaradial (0 t o 100 mu M) inhibited oxidase activity in both groups of cells by simi lar degrees, while the specific cPLA(2) inhibitor AACO-CF3 (0 to 50 mu M) failed to affect activity in either group. Inhibition of platelet- activating factor (PAF), cycloxygenase, and 5-lipoxygenase-activating protein by hexanolamino-PAF (0 to 25 mu M), flurbiprofen (0 to 25 mu M ), and MK886 (0 to 5 mu M), respectively, had no effect upon oxidase a ctivity. However, the direct inhibition of 5-lipoxygenase by caffeic a cid or lipoxin A(4) resulted in a similar concentration-dependent atte nuation of oxidase activity in both primed and unprimed cells. Leukotr iene B-4 (LTB4) release from primed neutrophils was comparable to that from unprimed cells with the exception of phorbol myristate acetate-s timulated cells, which released fivefold more LTB4 than control. Taken together, these results suggest that it is arachidonic acid per se, a nd not its metabolites, that is important in priming of the neutrophil NADPH oxidase by dialysis effluent.