title: Mast cell tumor necrosis factor alpha production is regulated by MEK kinases.
abstract: 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.
authors.affiliation: 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.
authors.forename: T
authors.initials: T
authors.lastname: Ishizuka
authors.forename: N
authors.initials: N
authors.lastname: Terada
authors.forename: P
authors.initials: P
authors.lastname: Gerwins
authors.forename: E
authors.initials: E
authors.lastname: Hamelmann
authors.forename: A
authors.initials: A
authors.lastname: Oshiba
authors.forename: G R
authors.initials: GR
authors.lastname: Fanger
authors.forename: G L
authors.initials: GL
authors.lastname: Johnson
authors.forename: E W
authors.initials: EW
authors.lastname: Gelfand
mesh_terms: 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
chemical_list: 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