Cooperativity between oxidants and tumor necrosis factor in the activation of nuclear factor (NF)-kappaB: requirement of Ras/mitogen-activated protein kinases in the activation of NF-kappaB by oxidants

Am J Respir Cell Mol Biol. 1999 May;20(5):942-52. doi: 10.1165/ajrcmb.20.5.3452.


The transcription factor nuclear factor (NF)-kappaB is activated by oxidative stress or cytokines and is critical to the activation of inflammatory genes. Here, we report that hydrogen peroxide or 3-morpholinosydnonimine, which simultaneously releases nitric oxide and superoxide, synergize with the cytokine tumor necrosis factor (TNF)-alpha to activate NF-kappaB in rat lung epithelial cells, suggesting that signaling pathways elicited by reactive oxygen species (ROS)/reactive nitrogen species (RNS) are different from TNF-induced signaling. These findings were substantiated by observations that levels of IkappaB-alpha did not change after exposure to ROS/RNS, whereas a rapid depletion of IkappaB-alpha was observed in cells exposed to TNF. In addition, the proteosome inhibitor MG132 did not affect activation of NF-kappaB by ROS/RNS, whereas it abolished the TNF response. Transfection of a dominant negative Ras construct prevented the activation of NF-kappaB by ROS/RNS, demonstrating the requirement for Ras in the activation of NF-kappaB by oxidants. In contrast, TNF activated NF-kappaB in a Ras-independent fashion. Evaluation of members of the mitogen-activated protein kinase (MAPK) family as downstream effectors of Ras revealed the requirement of MAPK/ extracellular-regulated kinase (ERK) kinase kinase (MEKK)1 and c-Jun N-terminal kinases in the induction of NF-kappaB by both oxidants and TNF, whereas the MEK-ERK pathway negatively regulates NF-kappaB. Our findings demonstrate that cytokines and oxidants cooperate in the activation of transcription factors through distinct pathways, and suggest that anti-inflammatory and antioxidant therapies may be required in concert to prevent the activation of NF-kappaB-regulated genes important in the development of inflammatory diseases.

Publication types

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

MeSH terms

  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Cell Line, Transformed
  • DNA-Binding Proteins / metabolism
  • Enzyme Activation
  • Hydrogen Peroxide / pharmacology*
  • I-kappa B Proteins
  • Molsidomine / analogs & derivatives*
  • Molsidomine / pharmacology
  • NF-kappa B / metabolism*
  • Oxidative Stress
  • Rats
  • Tumor Necrosis Factor-alpha / physiology*
  • ras Proteins / metabolism


  • DNA-Binding Proteins
  • I-kappa B Proteins
  • NF-kappa B
  • Tumor Necrosis Factor-alpha
  • linsidomine
  • Hydrogen Peroxide
  • Molsidomine
  • Calcium-Calmodulin-Dependent Protein Kinases
  • ras Proteins