title: Rapamycin enhances LPS induction of tissue factor and tumor necrosis factor-alpha expression in macrophages by reducing IL-10 expression.
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.
authors.affiliation: Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, 3901 Rainbow Boulevard, MS-1018, Kansas City, KS 66160, USA.
authors.forename: Alyson K
authors.initials: AK
authors.lastname: Baker
authors.forename: Ruipeng
authors.initials: R
authors.lastname: Wang
authors.forename: Nigel
authors.initials: N
authors.lastname: Mackman
authors.forename: James P
authors.initials: JP
authors.lastname: Luyendyk
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000502:physiology; D002478:Cells, Cultured; D025461:Feedback, Physiological; D005260:Female; D005786:Gene Expression Regulation; D016753:Interleukin-10 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases; D013925:Thromboplastin / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D002352:Carrier Proteins; D016753:Interleukin-10; D008070:Lipopolysaccharides; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D051057:Proto-Oncogene Proteins c-akt; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; D013925:Thromboplastin; D014409:Tumor Necrosis Factor-alpha; C546843:mTOR protein, mouse; C487757:Pten protein, mouse