Effects of protein kinase C and phospholipase C inhibitors on IgE-dependent and IgE-independent basophil histamine release.
OBJECTIVE
This study was aimed to evaluate the effects of two protein kinase C (PKC) inhibitors (staurosporine and chelerythrine) and one phospholipase C (PLC) inhibitor (U73122) on basophil histamine release induced by anti-IgE, N-formyl-methionyl-leucyl-phenylalanine (FMLP), IL-3 and GM-CSF.


METHODS
Leukocytes were suspended in solutions containing physiological or low Na+ concentrations, since IL-3 and GM-CSF were shown to induce histamine release only when the inhibitory effect of extracellular Na+ has been removed. After incubation with PKC and PLC inhibitors, the stimuli were added and histamine release was measured by an automated fluorometric method.


RESULTS
Staurosporine and chelerythrine exerted a significant inhibitory effect on histamine release induced by anti-IgE, IL-3 and GM-CSF at concentrations much higher than those required to inhibit PKC. FMLP-induced histamine release in a physiological Na+-containing medium was not significantly modified by staurosporine, although it was reduced by high concentrations of chelerythrine. A slight inhibition by high concentrations of staurosporine was found when basophils were suspended in a low Na+ medium. U73122 exerted a significant and dose-dependent inhibitory effect on basophil histamine release induced by anti-IgE, FMLP, IL-3 and GM-CSF.


CONCLUSIONS
These results suggest that a prodegranulatory role of PKC in basophil histamine release induced by anti-IgE, FMLP, IL-3 and GM-CSF is unlikely; conversely, it is conceivable that PLC has a role in signal transduction and histamine release induced by the above stimuli.
Tedeschi
A
A
Respiratory Allergy and Immunopharmacology Unit, Third Division of Internal Medicine, IRCCS Ospedale Maggiore Policlinico, Milan, Italy. albited@tin.it
Lorini
M
M
Gibelli
S
S
Miadonna
A
A
D000470:Alkaloids; D001491:Basophils / Q000378:metabolism*; D053119:Benzophenanthridines; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004963:Estrenes / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects*; D006801:Humans; D007073:Immunoglobulin E / Q000502:physiology*; D007377:Interleukin-3 / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D011760:Pyrrolidinones / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000502:physiology*
D000470:Alkaloids; D053119:Benzophenanthridines; D004791:Enzyme Inhibitors; D004963:Estrenes; D007377:Interleukin-3; D010617:Phenanthridines; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D007073:Immunoglobulin E; D009240:N-Formylmethionine Leucyl-Phenylalanine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; C016299:chelerythrine; D011493:Protein Kinase C; D010738:Type C Phospholipases; D019311:Staurosporine