Comparison of the roles of mitogen-activated protein kinase kinase and phosphatidylinositol 3-kinase signal transduction in neutrophil effector function.
Although it is known that many stimuli can activate mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinases (PI3K) in human neutrophils, little is known concerning either the mechanisms or function of this activation. We have utilized a selective inhibitor of MAPK kinase (MEK), PD098059, and two inhibitors of PI3K, wortmannin and LY294002, to investigate the roles of these kinases in the regulation of neutrophil effector functions. Granulocyte/macrophage colony-stimulating factor, platelet-activating factor (PAF) and N-formylmethionyl-leucyl-phenylalanine are capable of activating both p44ERK1 and p42ERK2 MAPKs and phosphotyrosine-associated PI3K in human neutrophils. The activation of extracellular signal-related protein kinases (ERKs) is correlated with the activation of p21ras by both tyrosine kinase and G-protein-coupled receptors as measured by a novel assay for GTP loading. Wortmannin and LY294002 inhibit, to various degrees, superoxide generation, neutrophil migration and PAF release. Incubation with PD098059, however, inhibits only the PAF release stimulated by serum-treated zymosan. This demonstrates that, while neither MEK nor ERK kinases are involved in the activation of respiratory burst or neutrophil migration, inhibition of PAF release suggests a potential role in the activation of cytosolic phospholipase A2. PI3K isoforms, however, seem to have a much wider role in regulating neutrophil functioning.
Coffer
P J
PJ
Department of Pulmonary Diseases, G03.550, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Geijsen
N
N
M'rabet
L
L
Schweizer
R C
RC
Maikoe
T
T
Raaijmakers
J A
JA
Lammers
J W
JW
Koenderman
L
L
D000730:Androstadienes / Q000494:pharmacology; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002630:Chemotactic Factors / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009025:Morpholines / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D015689:Oncogene Protein p21(ras) / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010972:Platelet Activating Factor / Q000378:metabolism / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism*; D016897:Respiratory Burst / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D000077191:Wortmannin; D015054:Zymosan / Q000494:pharmacology
D000730:Androstadienes; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002630:Chemotactic Factors; D002867:Chromones; D016207:Cytokines; D005419:Flavonoids; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009025:Morpholines; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015689:Oncogene Protein p21(ras); D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010972:Platelet Activating Factor; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D000077191:Wortmannin; D015054:Zymosan; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one