IFN-gamma + LPS induction of iNOS is modulated by ERK, JNK/SAPK, and p38(mapk) in a mouse macrophage cell line

Am J Physiol Cell Physiol. 2001 Mar;280(3):C441-50. doi: 10.1152/ajpcell.2001.280.3.C441.


Nitric oxide (NO.) produced by inducible nitric oxide synthase (iNOS) mediates a number of important physiological and pathophysiological processes. The objective of this investigation was to examine the role of mitogen-activated protein kinases (MAPKs) in the regulation of iNOS and NO. by interferon-gamma (IFN-gamma) + lipopolysaccharide (LPS) in macrophages using specific inhibitors and dominant inhibitory mutant proteins of the MAPK pathways. The signaling pathway utilized by IFN-gamma in iNOS induction is well elucidated. To study signaling pathways that are restricted to the LPS-signaling arm, we used a subclone of the parental RAW 264.7 cell line that is unresponsive to IFN-gamma alone with respect to iNOS induction. In this RAW 264.7gammaNO(-) subclone, IFN-gamma and LPS are nevertheless required for synergistic activation of the iNOS promoter. We found that extracellular signal-regulated kinase (ERK) augmented and p38(mapk) inhibited IFN-gamma + LPS induction of iNOS. Dominant-negative MAPK kinase-4 inhibited iNOS promoter activation by IFN-gamma + LPS, also implicating the c-Jun NH(2)-terminal kinase (JNK) pathway in mediating iNOS induction. Inhibition of the ERK pathway markedly reduced IFN-gamma + LPS-induced tumor necrosis factor-alpha protein expression, providing a possible mechanism by which ERK augments iNOS expression. The inhibitory effect of p38(mapk) appears more complex and may be due to the ability of p38(mapk) to inhibit LPS-induced JNK activation. These results indicate that the MAPKs are important regulators of iNOS-NO. expression by IFN-gamma + LPS.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Line
  • DNA-Binding Proteins
  • Drug Synergism
  • Enzyme Induction / physiology
  • Enzyme Inhibitors / pharmacology
  • Genes, Dominant
  • Imidazoles / pharmacology
  • Interferon-gamma / pharmacology*
  • Interleukin-1 / physiology
  • JNK Mitogen-Activated Protein Kinases
  • Lipopolysaccharides / pharmacology*
  • MAP Kinase Kinase 1
  • MAP Kinase Kinase 4*
  • Macrophages / metabolism*
  • Mice
  • Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase Kinases / genetics
  • Mitogen-Activated Protein Kinase Kinases / pharmacology
  • Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • Mitogen-Activated Protein Kinases / physiology*
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase / metabolism*
  • Nitric Oxide Synthase Type II
  • Nitrites / metabolism
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / physiology*
  • Phosphorylation / drug effects
  • Promoter Regions, Genetic / drug effects
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Pyridines / pharmacology
  • RNA-Binding Proteins
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors
  • Tumor Necrosis Factor-alpha / metabolism


  • DNA-Binding Proteins
  • Enzyme Inhibitors
  • Imidazoles
  • Interleukin-1
  • Lipopolysaccharides
  • Nitrites
  • Nuclear Proteins
  • Pa2g4 protein, mouse
  • Pyridines
  • RNA-Binding Proteins
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • Protein-Serine-Threonine Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 1
  • MAP Kinase Kinase 4
  • Map2k1 protein, mouse
  • Map2k4 protein, mouse
  • Mitogen-Activated Protein Kinase Kinases
  • SB 203580