Effect of 22-32 carbon n-3 polyunsaturated fatty acids on superoxide production in human neutrophils: synergism of docosahexaenoic acid with f-met-leu-phe and phorbol ester.
Docosahexaenoic (22:6 n-3) and eicosapentaenoic acid (20:5 n-3) stimulated the oxygen-dependent respiratory burst in intact neutrophils in a dose-dependent manner as measured by either superoxide dismutase (SOD)-inhibitable cytochrome c reduction and lucigenin-dependent chemiluminescence. A number of longer chain hexaenoic acids isolated from ram testis (22 to 32 carbon fatty acids) showed a diminishing response with increasing carbon chain length. 22:6 acted synergistically to enhance the responses to two other neutrophil agonists, f-met-leu-phe (FMLP) and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Whereas 22:6-induced chemiluminescence was markedly inhibited by pre-treatment with cytochalasin B, the response to FMLP was augmented, while TPA-induced activation was largely unaffected by cytochalasin B. 22:6-induced activation of neutrophils is independent of protein kinase C, as 22:6, unlike TPA, did not cause the membrane translocation of this enzyme. Furthermore, the putative protein kinase C inhibitor H-7 [1-(5-isoquinolinylsulphonyl)-2-methylpiperazine] had little effect on 22:6-induced chemiluminescence. In contrast, 22:6-induced activation was extremely sensitive to the calmodulin antagonist W-7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide], indicating that calmodulin-dependent enzymes may be involved in the responses to 22:6. These results suggest that different mechanisms are involved in the 22:6-, FMLP- and TPA-induced activation of neutrophil NADPH-oxidase.
Poulos
A
A
Department of Chemical Pathology, Department of Immunology and University of Adelaide Department of Paediatrics, Adelaide Children's Hospital, Australia.
Robinson
B S
BS
Ferrante
A
A
Harvey
D P
DP
Hardy
S J
SJ
Murray
A W
AW
D002147:Calmodulin / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D004357:Drug Synergism; D005227:Fatty Acids / Q000737:chemistry; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D011493:Protein Kinase C / Q000097:blood; D013449:Sulfonamides / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D002147:Calmodulin; D005227:Fatty Acids; D013449:Sulfonamides; D013481:Superoxides; D004281:Docosahexaenoic Acids; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; C017967:W 7; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate