Priming of human neutrophil respiratory burst by granulocyte/macrophage colony-stimulating factor (GM-CSF) involves partial phosphorylation of p47(phox).
Neutrophil superoxide production can be potentiated by prior exposure to "priming" agents such as granulocyte/macrophage colony stimulating factor (GM-CSF). Because the mechanism underlying GM-CSF-dependent priming is not understood, we investigated the effects of GM-CSF on the phosphorylation of the cytosolic NADPH oxidase components p47(phox) and p67(phox). Preincubation of neutrophils with GM-CSF alone increased the phosphorylation of p47(phox) but not that of p67(phox). Addition of formyl-methionyl-leucyl-phenylalanine (fMLP) to GM-CSF-pretreated neutrophils resulted in more intense phosphorylation of p47(phox) than with GM-CSF alone and fMLP alone. GM-CSF-induced p47(phox) phosphorylation was time- and concentration-dependent and ran parallel to the priming effect of GM-CSF on superoxide production. Two-dimensional tryptic peptide mapping of p47(phox) showed that GM-CSF induced phosphorylation of one major peptide. fMLP alone induced phosphorylation of several peptides, an effect enhanced by GM-CSF pretreatment. In contrast to fMLP and phorbol 12-myristate 13-acetate, GM-CSF-induced phosphorylation of p47(phox) was not inhibited by the protein kinase C inhibitor GF109203X. The protein-tyrosine kinase inhibitor genistein and the phosphatidylinositol 3-kinase inhibitor wortmannin inhibited the phosphorylation of p47(phox) induced by GM-CSF and by fMLP but not that induced by phorbol 12-myristate 13-acetate. GM-CSF alone did not induce p47(phox) or p67(phox) translocation to the membrane, but neutrophils treated consecutively with GM-CSF and fMLP showed an increase (compared with fMLP alone) in membrane translocation of p47(phox) and p67(phox). Taken together, these results show that the priming action of GM-CSF on the neutrophil respiratory burst involves partial phosphorylation of p47(phox) on specific serines and suggest the involvement of a priming pathway regulated by protein-tyrosine kinase and phosphatidylinositol 3-kinase.
Dang
P M
PM
INSERM U. 479, Centre Hospitalier Universitaire Xavier Bichat, Faculté de Medecine, 16 rue Henri Huchard, 75018 Paris, France.
Dewas
C
C
Gaudry
M
M
Fay
M
M
Pedruzzi
E
E
Gougerot-Pocidalo
M A
MA
El Benna
J
J
D001692:Biological Transport; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D016897:Respiratory Burst / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism
D004791:Enzyme Inhibitors; D010750:Phosphoproteins; C079789:neutrophil cytosol factor 67K; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D011493:Protein Kinase C