Mast cell tumor necrosis factor alpha production is regulated by MEK kinases.
Mast cells synthesize and secrete specific cytokines and chemokines which play an important role in allergic inflammation. Aggregation of the high-affinity Fc receptor (FcepsilonRI) for immunoglobulin E (IgE) in MC/9 mouse mast cells stimulates the synthesis and secretion of tumor necrosis factor alpha (TNF-alpha). FcepsilonRI aggregation activates several sequential protein kinase pathways, leading to increased activity of extracellular signal-regulated kinases (ERKs), c-Jun amino-terminal kinases (JNKs), and the p38 mitogen-activated protein (MAP) kinase. Inhibition of ERKs with the compound PD 098059 had little effect on FcepsilonRI-stimulated TNF-alpha production. Aggregation of FcepsilonRI stimulated MEK kinase 1 (MEKK1) activity, which activates JNK kinase (JNKK), the kinase that phosphorylates and activates JNKs. Expression of activated MEKK1 (DeltaMEKK1) in MC/9 cells strongly stimulated JNK activity but only weakly stimulated p38 activity, and it induced a large activation of TNF-alpha promoter-regulated luciferase gene expression. Inhibitory mutant JNK2 expressed in MC/9 cells significantly blunted FcepsilonRI stimulation of TNF-alpha promoter-driven luciferase expression. Wortmannin, an inhibitor of phosphatidylinositol 3-kinase, diminished FcepsilonRI-mediated TNF-alpha synthesis, significantly blunted JNK activation and TNF-alpha promoter-driven luciferase expression, and only weakly inhibited p38 kinase activation. Inhibition of NFkappaB activation resulting from DeltaMEKK1 expression or FcepsilonRI stimulation did not affect TNF-alpha promoter-driven luciferase expression. Our findings define a MEKK-regulated JNK pathway activated by FcepsilonRI that regulates TNF-alpha production in mast cells.
Ishizuka
T
T
Division of Basic Sciences, Department of Pediatrics, and Program in Molecular Signal Transduction, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206, USA.
Terada
N
N
Gerwins
P
P
Hamelmann
E
E
Oshiba
A
A
Fanger
G R
GR
Johnson
G L
GL
Gelfand
E W
EW
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005982:Glutathione Transferase; D007093:Imidazoles / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis; D048728:MAP Kinase Kinase Kinase 1; D008407:Mast Cells / Q000276:immunology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D000077191:Wortmannin
D000730:Androstadienes; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011993:Recombinant Fusion Proteins; D013844:Thiazoles; D014409:Tumor Necrosis Factor-alpha; C052026:6-(4-fluorophenyl)-2,3-dihydro-5-(4-pyridinyl)imidazo(2,1-b)thiazole; D008156:Luciferases; D005982:Glutathione Transferase; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482578:Map3k1 protein, mouse; D000077191:Wortmannin