Ortho-substituted polychlorinated biphenyls activate respiratory burst measured as luminol-amplified chemoluminescence in human granulocytes.
The effect of polychlorinated biphenyls (PCBs) on the activation of respiratory burst measured as luminol-amplified chemoluminescence in human granulocytes is elucidated here. Chemoluminescence was stimulated in a concentration-dependent manner (ED50 approximately 10 microM) by ortho-substituted PCB congeners, while meta- and para-substituted congeners had no significant effect. Two ortho-substituted PCB congeners were chosen for the mechanistic studies, namely 2,2',4,4'-TeCB and 2,2'-DCB, since they have been used in previous studies by others. In the absence of extracellular calcium, the respiratory burst in response to 2,2'-DCB and 2,2',4,4'-TeCB was reduced by 63% and 82%, respectively. Bisindolylmaleimide, which inhibits protein kinase C, reduced activated chemoluminescence by 2,2'-DCB, 2,2',4,4'-TeCB, N-formyl-methionyl-leucyl-phenylalanine, and phorbol 12-myristate 13-acetate. Neomycin, which inhibits phospholipase C, had a slight, but significant, effect on the 2,2',4,4'-TeCB-activated chemoluminescence but had a more pronounced effect on the 2,2'-DCB-activated chemoluminescence. 2,2'-DCB and 2,2',4,4'-TeCB significantly increased phospholipase D (PLD) activity measured as the amount of 14C-phosphatidylbutanol formed. Ethanol (1%), a phospholipase D modulator, reduced the response to 2,2'-DCB and 2,2',4,4'-TeCB by 72% and 75%, respectively. Furthermore, wortmannin (25 nM), a phosphatidylinositol 3-kinase, and genistein, a more unspecific tyrosine kinase inhibitor, reduced chemoluminescence in response to PCB. In conclusion, our results indicate that PCB-activated chemoluminescence is dependent on the Ca(2+)-dependent phospholipase D or phospholipase C, phosphatidylinositol 3-kinase, and protein kinase C activation prior to activation of the NADPH oxidase. Defects in neutrophhil functions upon exposure to PCB may render a greater susceptibility in the host to invading microorganisms or evoke inappropriate inflammatory responses leading to tissue injury.
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Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller, Norway.
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D000730:Androstadienes / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D006098:Granulocytes / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008163:Luminescent Measurements; D008165:Luminol; D008301:Maleimides / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000633:toxicity*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D016897:Respiratory Burst / Q000187:drug effects*; D013329:Structure-Activity Relationship; D013755:Tetradecanoylphorbol Acetate; D000077191:Wortmannin
D000730:Androstadienes; D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D010726:Phosphodiesterase Inhibitors; C012280:2,2'-dichlorobiphenyl; D000431:Ethanol; C035976:2,4,2',4'-tetrachlorobiphenyl; D008165:Luminol; D011078:Polychlorinated Biphenyls; D011493:Protein Kinase C; D010739:Phospholipase D; C088060:bisindolylmaleimide; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; D000077191:Wortmannin