Tumor necrosis factor alpha (TNFalpha) stimulates Map4k4 expression through TNFalpha receptor 1 signaling to c-Jun and activating transcription factor 2

J Biol Chem. 2007 Jul 6;282(27):19302-12. doi: 10.1074/jbc.M700665200. Epub 2007 May 11.

Abstract

Tumor necrosis factor alpha (TNFalpha) is a cytokine secreted by macrophages and adipocytes that contributes to the low grade inflammation and insulin resistance observed in obesity. TNFalpha signaling decreases peroxisome proliferator-activated receptor gamma and glucose transporter isoform 4 (GLUT4) expression in adipocytes, impairing insulin action, and this is mediated in part by the yeast Ste20 protein kinase ortholog Map4k4. Here we show that Map4k4 expression is selectively up-regulated by TNFalpha, whereas the expression of the protein kinases JNK1/2, ERK1/2, p38 stress-activated protein kinase, and mitogen-activated protein kinase kinases 4/7 shows little or no response. Furthermore, the cytokines interleukin 1beta (IL-1beta) and IL-6 as well as lipopolysaccharide fail to increase Map4k4 mRNA levels in cultured adipocytes under conditions where TNFalpha elicits a 3-fold effect. Using agonistic and antagonistic antibodies and small interfering RNA (siRNA) against TNFalpha receptor 1 (TNFR1) and TNFalpha receptor 2 (TNFR2), we show that TNFR1, but not TNFR2, mediates the increase in Map4k4 expression. TNFR1, but not TNFR2, also mediates a potent effect of TNFalpha on the phosphorylation of JNK1/2 and p38 stress-activated protein kinase and their downstream transcription factor substrates c-Jun and activating transcription factor 2 (ATF2). siRNA-based depletion of c-Jun and ATF2 attenuated TNFalpha action on Map4k4 mRNA expression. Consistent with this concept, the phosphorylation of ATF2 along with the expression and phosphorylation of c-Jun by TNFalpha signaling was more robust and prolonged compared with that of IL-1beta, which failed to modulate Map4k4. These data reveal that TNFalpha selectively stimulates the expression of a key component of its own signaling pathway, Map4k4, through a TNFR1-dependent mechanism that targets the transcription factors c-Jun and ATF2.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3T3 Cells
  • Activating Transcription Factor 2 / metabolism*
  • Adipocytes / metabolism
  • Animals
  • Glucose Transporter Type 4 / metabolism
  • Inflammation / metabolism
  • Insulin Resistance
  • Interleukin-1beta / metabolism
  • Interleukin-1beta / pharmacology
  • Interleukin-6 / metabolism
  • Interleukin-6 / pharmacology
  • Lipopolysaccharides / pharmacology
  • Macrophages / metabolism
  • Mice
  • Mitogen-Activated Protein Kinases / biosynthesis*
  • NF-kappaB-Inducing Kinase
  • PPAR gamma / metabolism
  • Phosphorylation
  • Protein Serine-Threonine Kinases / biosynthesis*
  • Proto-Oncogene Proteins c-jun / antagonists & inhibitors
  • Proto-Oncogene Proteins c-jun / metabolism*
  • RNA, Small Interfering / pharmacology
  • Receptors, Tumor Necrosis Factor, Type I / agonists
  • Receptors, Tumor Necrosis Factor, Type I / metabolism*
  • Receptors, Tumor Necrosis Factor, Type II / agonists
  • Receptors, Tumor Necrosis Factor, Type II / metabolism
  • Signal Transduction* / drug effects
  • Tumor Necrosis Factor-alpha / metabolism*
  • Tumor Necrosis Factor-alpha / pharmacology
  • Up-Regulation* / drug effects

Substances

  • Activating Transcription Factor 2
  • Atf2 protein, mouse
  • Glucose Transporter Type 4
  • Interleukin-1beta
  • Interleukin-6
  • Lipopolysaccharides
  • PPAR gamma
  • Proto-Oncogene Proteins c-jun
  • RNA, Small Interfering
  • Receptors, Tumor Necrosis Factor, Type I
  • Receptors, Tumor Necrosis Factor, Type II
  • Slc2a4 protein, mouse
  • Tumor Necrosis Factor-alpha
  • Protein Serine-Threonine Kinases
  • Mitogen-Activated Protein Kinases