Mast Cell Tumor Necrosis Factor α Production is Regulated by MEK Kinases

• Published in: Proceedings of the National Academy of Sciences - PNAS 1997-06, Vol.94 (12), p.6358-6363
• Main Authors: Ishizuka, Tamotsu, Terada, Naohiro, Gerwins, Pär, Hamelmann, Eckard, Oshiba, Akihiro, Fanger, Gary R., Johnson, Gary L., Gelfand, Erwin W.
• Format: Article
• Language: English
• Subjects: Aggregation; Androstadienes - pharmacology; Animals; Anti-Inflammatory Agents, Non-Steroidal - pharmacology; Biological Sciences; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Cell Line; Cellular biology; Cytokines; Enzyme Activation; Enzyme Inhibitors - pharmacology; Gene expression; Gene expression regulation; Genes; Glutathione Transferase; Government regulation; Imidazoles - pharmacology; JNK Mitogen-Activated Protein Kinases; Kinetics; Luciferases - biosynthesis; MAP Kinase Kinase Kinase 1; Mast cells; Mast Cells - immunology; Mice; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinases; Ova; Plasmids; Promoter Regions, Genetic; Protein-Serine-Threonine Kinases - metabolism; Protein-Tyrosine Kinases - metabolism; Recombinant Fusion Proteins - metabolism; Thiazoles - pharmacology; Transcription, Genetic - drug effects; Transfection; Tumor Necrosis Factor-alpha - biosynthesis; Wortmannin
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.12.6358

Mast cells synthesize and secrete specific cytokines and chemokines which play an important role in allergic inflammation. Aggregation of the high-affinity Fc receptor (Fcε RI) for immunoglobulin E (IgE) in MC/9 mouse mast cells stimulates the synthesis and secretion of tumor necrosis factor α (TNF-α ). Fcε RI 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 Fcε RI-stimulated TNF-α production. Aggregation of Fcε RI stimulated MEK kinase 1 (MEKK1) activity, which activates JNK kinase (JNKK), the kinase that phosphorylates and activates JNKs. Expression of activated MEKK1 (Δ MEKK1) in MC/9 cells strongly stimulated JNK activity but only weakly stimulated p38 activity, and it induced a large activation of TNF-α promoter-regulated luciferase gene expression. Inhibitory mutant JNK2 expressed in MC/9 cells significantly blunted Fcε RI stimulation of TNF-α promoter-driven luciferase expression. Wortmannin, an inhibitor of phosphatidylinositol 3-kinase, diminished Tcε RI-mediated TNF-α synthesis, significantly blunted JNK activation and TNF-α promoter-driven luciferase expression, and only weakly inhibited p38 kinase activation. Inhibition of NFκ B activation resulting from Δ MEKK1 expression or Fcε RI stimulation did not affect TNF-α promoter-driven luciferase expression. Our findings define a MEKK-regulated JNK pathway activated by Fcε RI that regulates TNF-α production in mast cells.