Effects of genetic and pharmacological inhibition of TNF-alpha in the regulation of inflammation in macrophages

Pharmacol Res. 2009 Oct;60(4):332-40. doi: 10.1016/j.phrs.2009.05.001. Epub 2009 May 18.

Abstract

Tumour necrosis factor-alpha (TNF-alpha) is an inflammatory cytokine produced by circulating monocytes and resident macrophages during acute inflammation and is responsible for a diverse range of signalling events within cells, leading to necrosis or apoptosis. The biologic activities of TNF are mediated by two receptors TNFR1 and TNFR2, although a lot of studies demonstrated that most of the biological activities of TNF-alpha are mediated through TNFR1. In the present study, we want to evaluate the role of TNF-alpha on regulation of in vitro models of inflammation. In particular we used peritoneal macrophages, from TNF-alphaR1 knock out and TNF-alphaR1 wild-type mice, stimulated with LPS 10 microg/ml and IFN-gamma 100 U/ml. Our results showed that the deletion of TNF-alphaR1 gene significantly reduced the degree of (i) MAPK activation, (ii) IkappaB-alpha degradation, (iii) phosphorylation of Ser536 on the NF-kappaB subunit p65 and (iv) iNOS and COX-2 expression. In addition, to confirm the pivotal role of TNF-alpha on regulation of peritoneal macrophages inflammation, we have also investigated the protective effects of infliximab, a TNF-alpha chimeric mouse/human IgG1 antibody against TNF-alpha. As shown in the present study, the cell incubation with infliximab (0.1 microg/ml, 1 microg/ml and 10 microg/ml) significantly leads to a concentration-dependent inhibition of the inflammatory mediators above described. In conclusion, our study demonstrates that pharmacological and genetic inhibition of the TNF/TNFR1 binding reduce the degree of macrophages inflammation caused by LPS/IFN-gamma stimulation.

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Antibodies, Monoclonal / pharmacology*
  • Cell Survival / drug effects
  • Cells, Cultured
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism
  • Gene Deletion
  • Gene Expression / drug effects
  • Infliximab
  • MAP Kinase Signaling System / drug effects
  • Macrophages / cytology
  • Macrophages / drug effects*
  • Macrophages / immunology
  • Mice
  • Mice, Knockout
  • NF-kappa B / metabolism
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism
  • Peritoneum / cytology
  • Receptors, Tumor Necrosis Factor, Type I / genetics*
  • Receptors, Tumor Necrosis Factor, Type I / metabolism
  • Tumor Necrosis Factor-alpha / immunology*

Substances

  • Anti-Inflammatory Agents
  • Antibodies, Monoclonal
  • NF-kappa B
  • Receptors, Tumor Necrosis Factor, Type I
  • Tumor Necrosis Factor-alpha
  • Infliximab
  • Nitric Oxide Synthase Type II
  • Cyclooxygenase 2