title: Signal transducer and activator of transcription 3 is the dominant mediator of the anti-inflammatory effects of IL-10 in human macrophages.
abstract: The signaling mechanism by which the anti-inflammatory cytokine IL-10 mediates suppression of proinflammatory cytokine synthesis remains largely unknown. Macrophage-specific STAT3-null mice have demonstrated that STAT3 plays a critical role in the suppression of LPS-induced TNF-alpha release, although the mechanism by which STAT3 mediates this inhibition is still not clear. Using an adenoviral system, we have expressed a dominant negative (DN) STAT3 in human macrophages to broaden the investigation to determine the role of STAT3 in IL-10-mediated anti-inflammatory signaling and gene expression. Overexpression of STAT3 DN completely inhibited IL-10-induced suppressor of cytokine signaling 3, tissue inhibitor of MMP-1, TNF receptor expression, and the recently identified IL-10-inducible genes, T cell protein tyrosine phosphatase and signaling lymphocyte activation molecule. STAT3 DN also blocked IL-10-mediated inhibition of MHC class II and COX2 expression. In agreement with the studies in STAT3-null mice, overexpression of the STAT3 DN completely reversed the ability of IL-10 to inhibit LPS-mediated TNF-alpha and IL-6 production. However, real-time PCR analysis showed that STAT3 DN expression did not affect immediate suppression of TNF-alpha mRNA, but did reverse the suppression observed at later time points, suggesting a biphasic regulation of TNF-alpha mRNA levels by IL-10. In conclusion, although STAT3 does appear to be the dominant mediator of the majority of IL-10 functions, there are elements of its anti-inflammatory activity that are STAT3 independent.
authors.affiliation: Kennedy Institute of Rheumatology Division, Imperial College London, ARC Building, 1 Aspenlea Road, Hammersmith, London W6 8LH, United Kingdom.
authors.forename: Lynn
authors.initials: L
authors.lastname: Williams
authors.forename: Laura
authors.initials: L
authors.lastname: Bradley
authors.forename: Alexandra
authors.initials: A
authors.lastname: Smith
authors.forename: Brian
authors.initials: B
authors.lastname: Foxwell
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics; D015703:Antigens, CD / Q000096:biosynthesis / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000037:antagonists & inhibitors / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D005822:Genetic Vectors; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007136:Immunoglobulins / Q000096:biosynthesis / Q000235:genetics; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000502:physiology*; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D015850:Interleukin-6 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding / Q000235:genetics; D014176:Protein Biosynthesis; D054578:Protein Tyrosine Phosphatase, Non-Receptor Type 2; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D011506:Proteins / Q000502:physiology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D011956:Receptors, Cell Surface; D017452:Receptors, IgG / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D018124:Receptors, Tumor Necrosis Factor / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D047889:Receptors, Tumor Necrosis Factor, Type II; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D050796:STAT3 Transcription Factor; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology; D000093242:Interleukin-6 Inhibitors
chemical_list: D015703:Antigens, CD; D004247:DNA; D004268:DNA-Binding Proteins; D006023:Glycoproteins; D000949:Histocompatibility Antigens Class II; D007106:Immune Sera; D007136:Immunoglobulins; D018836:Inflammation Mediators; D016753:Interleukin-10; D015850:Interleukin-6; D008070:Lipopolysaccharides; D054578:Protein Tyrosine Phosphatase, Non-Receptor Type 2; D017027:Protein Tyrosine Phosphatases; D011506:Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017452:Receptors, IgG; D018124:Receptors, Tumor Necrosis Factor; D047889:Receptors, Tumor Necrosis Factor, Type II; D012097:Repressor Proteins; D050796:STAT3 Transcription Factor; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D015534:Trans-Activators; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D000093242:Interleukin-6 Inhibitors; C106644:SOCS3 protein, human; C494086:STAT3 protein, human; C516649:PTPN2 protein, human