A central role for the JNK pathway in mediating the antagonistic activity of pro-inflammatory cytokines against transforming growth factor-beta-driven SMAD3/4-specific gene expression

J Biol Chem. 2003 Jan 17;278(3):1585-93. doi: 10.1074/jbc.M206927200. Epub 2002 Nov 7.


We have focused our attention on the molecular events underlying the antagonistic activities of pro-inflammatory cytokines against transforming growth factor-beta (TGF-beta)/SMAD signaling. Using jnk1/2-knockout (jnk(-/-)) and I kappa B kinase-gamma/nemo(-/-) fibroblasts, we have determined the specific roles played by the JNK/AP-1 and NF-kappa B/Rel pathways in this phenomenon. We demonstrate that, in a cellular context devoid of JNK activity (i.e. jnk(-/-) fibroblasts), interleukin-1 and tumor necrosis factor-alpha (TNF-alpha) did not inhibit the formation of SMAD-DNA complexes and the resulting SMAD-driven transcription in response to TGF-beta. On the other hand, lack of NF-kappa B activity in nemo(-/-) fibroblasts did not affect the antagonistic effect of pro-inflammatory cytokines against TGF-beta. In the latter cell type, overexpression of antisense c-jun mRNA or of a dominant-negative form of MKK4 blocked the inhibitory activity of TNF-alpha, similar to what was observed in normal human dermal fibroblasts. Among JNK substrates, c-Jun and JunB (but not activating transcription factor-2) antagonized TGF-beta/SMAD signaling in a JNK-dependent manner. Overexpression of JNK1 in jnk(-/-) fibroblasts restored the ability of cytokines and Jun proteins to interfere with SMAD signaling. In junAA mouse embryo fibroblasts, in which c-Jun can no longer be phosphorylated by JNK, JunB substituted for c-Jun in mediating the cytokine effect against SMAD-driven transcription in a JNK-dependent manner. These results suggest a critical role for JNK-mediated c-Jun and JunB phosphorylation in transmitting the inhibitory effect of pro-inflammatory cytokines against TGF-beta-induced SMAD signaling. In addition, we demonstrate that such a JNK-dependent regulatory mechanism underlies the antagonistic activity of TNF-alpha against TGF-beta-induced up-regulation of type I and III collagens in fibroblasts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Transformed
  • Collagen / genetics
  • Collagen Type I*
  • Collagen Type I, alpha 1 Chain
  • Collagen Type III*
  • Cytokines / physiology*
  • DNA-Binding Proteins / genetics*
  • Gene Expression Regulation / physiology
  • Inflammation Mediators / physiology*
  • JNK Mitogen-Activated Protein Kinases
  • Mice
  • Mitogen-Activated Protein Kinases / metabolism*
  • Signal Transduction / physiology
  • Smad3 Protein
  • Smad4 Protein
  • Trans-Activators / genetics*
  • Transforming Growth Factor beta / physiology*
  • Tumor Necrosis Factor-alpha / physiology


  • COL3A1 protein, human
  • Collagen Type I
  • Collagen Type I, alpha 1 Chain
  • Collagen Type III
  • Cytokines
  • DNA-Binding Proteins
  • Inflammation Mediators
  • Smad3 Protein
  • Smad3 protein, mouse
  • Smad4 Protein
  • Smad4 protein, mouse
  • Trans-Activators
  • Transforming Growth Factor beta
  • Tumor Necrosis Factor-alpha
  • Collagen
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases