Modulation of the priming effects of platelet-activating factor on the release of interleukin-1 from lipopolysaccharide-stimulated rat spleen macrophages.
The pharmacologic modulation of the effect of platelet-activating factor (PAF) on the interleukin-1 (IL-1) activity present in the supernatants from lipopolysaccharide (LPS)-stimulated macrophages was investigated. Rat spleen macrophages were isolated by centrifugation on a Ficoll-Hypaque gradient followed by adherence on plastic petri dishes for 60 min at 37 degrees C under a 5% CO2/95% air atmosphere. The IL-1 content in the cell-free supernatants was assessed using the mouse thymocyte proliferation assay. Preincubation of macrophages for 10 min with 10 fM PAF prior to stimulation with 20 micrograms/ml LPS for 24 h markedly increased the IL-1 activity present in the supernatants from macrophages whereas no direct effect of PAF was noted. Although they had no direct effect, addition of L-651,392 (10 microM), a lipoxygenase inhibitor, or the oxygen-derived free radical scavenger mannitol (10 microM) during the 10-min preincubation period with PAF reversed by 105.0% and 79.9%, respectively, the action of the autacoid on IL-1 activity. Pertussis toxin (PT, 1 microgram/ml) decreased by 30% the LPS-induced IL-1 activity. Association of PT with PAF suppressed the enhancing effect of 10 fM PAF on the IL-1 activity present in the supernatants from LPS-stimulated macrophages. Thus, the enhancing effect of PAF on IL-1 release appears to be due to the production of lipoxygenase metabolites, leading to superoxide production and alterations of cAMP levels.
Pignol
B
B
Institut Henri Beaufour, France.
Henane
S
S
Chaumeron
S
S
Mencia-Huerta
J M
JM
Braquet
P
P
D000818:Animals; D004347:Drug Interactions; D005260:Female; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000008:administration & dosage; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D037342:Pertussis Toxin; D010640:Phenothiazines / Q000008:administration & dosage; D010972:Platelet Activating Factor / Q000008:administration & dosage*; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000166:cytology; D010566:Virulence Factors, Bordetella / Q000008:administration & dosage
D007375:Interleukin-1; D008070:Lipopolysaccharides; D016859:Lipoxygenase Inhibitors; D010640:Phenothiazines; D010972:Platelet Activating Factor; D010566:Virulence Factors, Bordetella; C053726:4-bromo-2,7-dimethoxy-3H-phenothiazin-3-one; D037342:Pertussis Toxin