Abstract
Experiments were performed to investigate the relative role of phospholipase A2 (PLA2) in the activation and cytokine-mediated priming of neutrophil superoxide production. PLA2 activity was measured with a radiometric assay which discriminates between PLA2 and the downstream enzyme, 5-lipoxygenase. In cells that had not been primed by prior incubation with granulocyte-macrophage colony stimulating factor (GM-CSF). PLA2 and NADPH oxidase were differentially stimulated by the chemotactic peptide N-formyl-met-leu-phe (FMLP), calcium ionophore, or phorbol ester. In addition, inhibition of PLA2 by mepacrine (0-100 μmol/l) did not concomitantly inhibit FMLP-stimulated superoxide production. These findings suggest that the activity of PLA2 and NADPH oxidase may be uncoupled in the unprimed cell. In cells preincubated with GM-CSF, time- and dose-dependent priming of FMLP-stimulated PLA2 responses were observed and inhibition of PLA2 by mepacrine was accompanied by the inhibition of FMLP-stimulated superoxide production down to the level of unprimed cells. The effect of mepacrine was not due to inhibition of FMLP receptor expression. These data suggest that a mepacrine-sensitive PLA2 may have a role in the GM-CSF mediated priming of superoxide production. Using ionophore-stimulated PLA2 activity as a model, we showed that Bordetella pertussis toxin did not inhibit GM-CSF mediated priming, demonstrating that a pertussis-sensitive GTP-binding protein does not mediate signal transduction from the GM-CSF receptor to PLA2. The tyrosine kinase inhibitor, genistein, selectively inhibited GM-CSF primed but not unprimed PLA2 activity, demonstrating that GM-CSF-mediated priming requires tyrosine kinase activity.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 804-814 |
| Number of pages | 11 |
| Journal | British Journal of Haematology |
| Volume | 92 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 1 1996 |
| Externally published | Yes |
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Keywords
- arachidonate
- granulocyte-macrophage colony-stimulating factor
- phospholipase A
- priming
- superoxide
ASJC Scopus subject areas
- Hematology
Cite this
The regulation of neutrophil phospholipase A2 by granulocyte-macrophage colony-stimulating factor and its role in priming superoxide production. / Roberts, Pamela J.; Williams, Sion Llewelyn; Linch, David C.
In: British Journal of Haematology, Vol. 92, No. 4, 01.01.1996, p. 804-814.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The regulation of neutrophil phospholipase A2 by granulocyte-macrophage colony-stimulating factor and its role in priming superoxide production
AU - Roberts, Pamela J.
AU - Williams, Sion Llewelyn
AU - Linch, David C.
PY - 1996/1/1
Y1 - 1996/1/1
N2 - Experiments were performed to investigate the relative role of phospholipase A2 (PLA2) in the activation and cytokine-mediated priming of neutrophil superoxide production. PLA2 activity was measured with a radiometric assay which discriminates between PLA2 and the downstream enzyme, 5-lipoxygenase. In cells that had not been primed by prior incubation with granulocyte-macrophage colony stimulating factor (GM-CSF). PLA2 and NADPH oxidase were differentially stimulated by the chemotactic peptide N-formyl-met-leu-phe (FMLP), calcium ionophore, or phorbol ester. In addition, inhibition of PLA2 by mepacrine (0-100 μmol/l) did not concomitantly inhibit FMLP-stimulated superoxide production. These findings suggest that the activity of PLA2 and NADPH oxidase may be uncoupled in the unprimed cell. In cells preincubated with GM-CSF, time- and dose-dependent priming of FMLP-stimulated PLA2 responses were observed and inhibition of PLA2 by mepacrine was accompanied by the inhibition of FMLP-stimulated superoxide production down to the level of unprimed cells. The effect of mepacrine was not due to inhibition of FMLP receptor expression. These data suggest that a mepacrine-sensitive PLA2 may have a role in the GM-CSF mediated priming of superoxide production. Using ionophore-stimulated PLA2 activity as a model, we showed that Bordetella pertussis toxin did not inhibit GM-CSF mediated priming, demonstrating that a pertussis-sensitive GTP-binding protein does not mediate signal transduction from the GM-CSF receptor to PLA2. The tyrosine kinase inhibitor, genistein, selectively inhibited GM-CSF primed but not unprimed PLA2 activity, demonstrating that GM-CSF-mediated priming requires tyrosine kinase activity.
AB - Experiments were performed to investigate the relative role of phospholipase A2 (PLA2) in the activation and cytokine-mediated priming of neutrophil superoxide production. PLA2 activity was measured with a radiometric assay which discriminates between PLA2 and the downstream enzyme, 5-lipoxygenase. In cells that had not been primed by prior incubation with granulocyte-macrophage colony stimulating factor (GM-CSF). PLA2 and NADPH oxidase were differentially stimulated by the chemotactic peptide N-formyl-met-leu-phe (FMLP), calcium ionophore, or phorbol ester. In addition, inhibition of PLA2 by mepacrine (0-100 μmol/l) did not concomitantly inhibit FMLP-stimulated superoxide production. These findings suggest that the activity of PLA2 and NADPH oxidase may be uncoupled in the unprimed cell. In cells preincubated with GM-CSF, time- and dose-dependent priming of FMLP-stimulated PLA2 responses were observed and inhibition of PLA2 by mepacrine was accompanied by the inhibition of FMLP-stimulated superoxide production down to the level of unprimed cells. The effect of mepacrine was not due to inhibition of FMLP receptor expression. These data suggest that a mepacrine-sensitive PLA2 may have a role in the GM-CSF mediated priming of superoxide production. Using ionophore-stimulated PLA2 activity as a model, we showed that Bordetella pertussis toxin did not inhibit GM-CSF mediated priming, demonstrating that a pertussis-sensitive GTP-binding protein does not mediate signal transduction from the GM-CSF receptor to PLA2. The tyrosine kinase inhibitor, genistein, selectively inhibited GM-CSF primed but not unprimed PLA2 activity, demonstrating that GM-CSF-mediated priming requires tyrosine kinase activity.
KW - arachidonate
KW - granulocyte-macrophage colony-stimulating factor
KW - phospholipase A
KW - priming
KW - superoxide
UR - http://www.scopus.com/inward/record.url?scp=0029881135&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029881135&partnerID=8YFLogxK
U2 - 10.1046/j.1365-2141.1996.432970.x
DO - 10.1046/j.1365-2141.1996.432970.x
M3 - Article
C2 - 8616070
AN - SCOPUS:0029881135
VL - 92
SP - 804
EP - 814
JO - British Journal of Haematology
JF - British Journal of Haematology
SN - 0007-1048
IS - 4
ER -