Evaluation of the role of mitogen-activated protein kinases in the expression of inducible nitric oxide synthase by IFN-gamma and TNF-alpha in mouse macrophages

• Published in: The Journal of immunology (1950) 1999-01, Vol.162 (1), p.415-422
• Main Authors: Chan, E D, Winston, B W, Uh, S T, Wynes, M W, Rose, D M, Riches, D W
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Animals; Calcium-Calmodulin-Dependent Protein Kinases - antagonists & inhibitors; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Calcium-Calmodulin-Dependent Protein Kinases - physiology; Enzyme Activation - immunology; Enzyme Induction; Gene Expression Regulation - immunology; Interferon-gamma - physiology; JNK Mitogen-Activated Protein Kinases; Macrophages - enzymology; MAP Kinase Kinase 4; MAP Kinase Kinase Kinase 1; Mice; Mice, Inbred C3H; Mitogen-Activated Protein Kinase 1 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Mutation; Nitric Oxide Synthase - antagonists & inhibitors; Nitric Oxide Synthase - biosynthesis; Nitric Oxide Synthase - genetics; Nitric Oxide Synthase Type II; p38 Mitogen-Activated Protein Kinases; Promoter Regions, Genetic - immunology; Protein-Serine-Threonine Kinases - antagonists & inhibitors; Protein-Tyrosine Kinases - antagonists & inhibitors; Tumor Necrosis Factor-alpha - physiology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.162.1.415

The expression of inducible nitric oxide synthase (iNOS) by macrophages is stimulated by coexposure to IFN-gamma and a number of stimuli, including TNF-alpha. Recent work has shown that TNF-alpha activates members of the mitogen-activated protein kinase family that subsequently trans-activate transcription factors implicated in the regulation of iNOS expression. The objective of this study was to systematically evaluate the role of: 1) p42mapk/erk2, 2) p46 c-Jun NH2-terminal kinase/stress-activated protein kinase (p46 JNK/SAPK), and 3) p38mapk in the induction of iNOS expression during costimulation of mouse macrophages with IFN-gamma and TNF-alpha. All three kinases were activated during costimulation with IFN-gamma and TNF-alpha. However, specific antagonism of the p42mapk/erk2 and p38mapk with PD98059 and SKF86002, respectively, had no effect on the induction of iNOS expression. In contrast, blockade of all three kinases with N-acetylcysteine completely blocked the induction of iNOS expression. In addition, specific antagonism of the JNK/SAPK upstream kinases MEKK (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase) and MKK4 (mitogen-activated protein kinase kinase 4) with dominant inhibitory mutants blocked transcriptional activation of the iNOS promoter in response to costimulation with IFN-gamma and TNF-alpha. Collectively, these findings support the involvement of p46 JNK/SAPK and its upstream kinases in regulating the induction of iNOS following ligation of the TNF-alpha receptor CD120a (p55) in the presence of IFN-gamma.