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Endogenous PMN‐derived reactive oxygen intermediates provide feedback regulation on respiratory burst signal transduction
Author(s) -
Derevianko Alexandre,
D'Amico Ronald,
Graeber Thomas,
Keeping Hugh,
Simms H. Hank
Publication year - 1997
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.62.2.268
Subject(s) - phospholipase d , respiratory burst , biology , phosphatidic acid , superoxide dismutase , myeloperoxidase , signal transduction , biochemistry , phospholipase c , receptor , endogeny , nadph oxidase , extracellular , microbiology and biotechnology , catalase , reactive oxygen species , enzyme , phospholipid , immunology , inflammation , membrane
The role of polymorphonuclear leukocytes (PMN) in stemming systemic infection is executed mainly by the utilization of molecular O 2 leading to the production of reactive oxygen intermediates (ROI). PMN‐derived ROI also serve as intra‐ and extracellular second messengers providing both positive and negative feedback on cellular autoregulation. We investigated the effect of endogenous ROI on two signal transducing pathways: the receptor (R)‐G‐protein‐phospholipase D (PLD) and receptor (R)‐G‐protein‐phospholipase C pathways responsible for the subsequent interleukin‐8 (IL‐8)‐induced PMN respiratory burst. Purified human PMN were primed with LPS adhered to plastic surfaces and stimulated with IL‐8 with or without the presence of each of five different selective ROI scavengers/antioxidants: DMSO, N a N 3 , L‐alanine, catalase, or superoxide dismutase. Total IL‐8 surface receptor expression was assessed by 125 I‐IL‐8 125 I‐labeled mAbs against IL‐8R type A and B binding assays; PLD activation was assessed by measuring formation of phosphatidyl ethanol (PEt) in the presence of ethanol; PLC activation was measured by quantitative conversion of [ 32 P]ATP‐labeled phosphatidic acid (PA) into diacylglycerol (DAG); expression of Gα‐inhibitory subunit was assessed by SDS‐PAGE and immunoblotting with polyclonal Abs against this subunit. Production of O 2 – , H 2 O 2 , HClO, and myeloperoxidase (MPO) in the experimental model was confirmed in a separate set of experiments. The overall impact of antioxidants on each component of the transducing tripartite complex was stimulatory; however, N a N 3 and SOD exhibited the most ubiquitous effect with consistent upregulation by N a N 3 of IL‐8R expression, whereas even trace amounts of externally added authentic MPO significantly down‐regulated the functional activity of both effector enzymes. These results demonstrate a multiple site‐specific targeting of the signal‐transducing complex by endogenous PMN‐derived ROI and an overall protective effect of ROI scavengers/antioxidants. J. Leukoc. Biol. 62: 268–276; 1997.