Rapamycin enhances LPS induction of tissue factor and tumor necrosis factor-alpha expression in macrophages by reducing IL-10 expression

Mol Immunol. 2009 Jul;46(11-12):2249-55. doi: 10.1016/j.molimm.2009.04.011. Epub 2009 May 17.

Abstract

Bacterial lipopolysaccharide (LPS) induces monocytes/macrophages to express proinflammatory cytokines and tissue factor (TF), the primary activator of the coagulation cascade. Anti-inflammatory signaling pathways including the phosphatidylinositol-3-kinase (PI3K)-Akt pathway inhibit proinflammatory and TF gene expression in macrophages. We determined the role of Akt, the mammalian target of rapamycin (mTOR) and interleukin-10 in the inhibition of LPS-induced proinflammatory cytokine and TF gene expression in peritoneal macrophages (PMs). We used wild type (WT) peritoneal macrophages (PMs), and PMs from PTEN(flox/flox)/LysMCre mice (PTEN(-/-) PMs), which have increased Akt activity. Pharmacologic inhibition of mTOR with rapamycin inhibited LPS induction of IL-10 mRNA and protein, and enhanced the expression of TF and the proinflammatory cytokine TNFalpha in WT PMs. Furthermore, neutralizing IL-10 with anti-IL-10 antibody enhanced LPS induction of TNFalpha and TF expression in WT PMs. The addition of recombinant IL-10 abolished rapamycin enhancement of LPS-induced TNFalpha and TF expression in WT PMs. Consistent with enhanced Akt activation, LPS-induced IL-10 expression was increased in PTEN(-/-) PMs compared to WT PMs. In contrast, LPS-induced TNFalpha and TF expression was significantly reduced in PTEN(-/-) PMs compared to WT PMs. However, the neutralizing IL-10 antibody did not completely prevent inhibition of LPS-induced TNFalpha and TF expression in PTEN(-/-) PMs. The results indicate that mTOR dependent IL-10 expression leads to inhibition of LPS induction of TF and the proinflammatory cytokine TNFalpha in WT macrophages. In contrast, the decrease in LPS-induced TNFalpha and TF expression in PTEN(-/-) PMs also requires an IL-10-independent pathway.

Publication types

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

MeSH terms

  • Animals
  • Carrier Proteins / physiology
  • Cells, Cultured
  • Feedback, Physiological
  • Female
  • Gene Expression Regulation
  • Interleukin-10 / biosynthesis*
  • Lipopolysaccharides / pharmacology*
  • Macrophages, Peritoneal / drug effects
  • Macrophages, Peritoneal / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • PTEN Phosphohydrolase / genetics
  • PTEN Phosphohydrolase / metabolism
  • Phosphatidylinositol 3-Kinases / physiology
  • Phosphotransferases (Alcohol Group Acceptor) / physiology
  • Proto-Oncogene Proteins c-akt / physiology
  • Signal Transduction
  • Sirolimus / pharmacology*
  • TOR Serine-Threonine Kinases
  • Thromboplastin / biosynthesis*
  • Tumor Necrosis Factor-alpha / biosynthesis*

Substances

  • Carrier Proteins
  • Lipopolysaccharides
  • Tumor Necrosis Factor-alpha
  • Interleukin-10
  • Thromboplastin
  • Phosphotransferases (Alcohol Group Acceptor)
  • mTOR protein, mouse
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • PTEN Phosphohydrolase
  • Pten protein, mouse
  • Sirolimus