title: Activation of STAT3 by IL-6 and IL-10 in primary human macrophages is differentially modulated by suppressor of cytokine signaling 3.
abstract: On human macrophages IL-10 acts as a more potent anti-inflammatory cytokine than IL-6, although both cytokines signal mainly via activation of the transcription factor STAT3. In this study we compare IL-10 and IL-6 signaling in primary human macrophages derived from blood monocytes. Pretreatment of macrophages with PMA or the proinflammatory mediators LPS and TNF-alpha blocks IL-6-induced STAT3 activation, whereas IL-10-induced activation of STAT3 remains largely unaffected. Although LPS induces the feedback inhibitor suppressor of cytokine signaling 3 (SOCS3) in macrophages, inhibition of IL-6 signal transduction by LPS occurs rapidly and does not depend on gene transcription. We also found that pretreatment of macrophages with IL-10 inhibits subsequent STAT3 activation by IL-6, whereas IL-10-induced STAT3 activation is not affected by preincubation with IL-6. This cross-inhibition is dependent on active transcription and might therefore be explained by different sensitivities of IL-10 and IL-6 signaling toward the feedback inhibitor SOCS3, which is induced by both cytokines. In contrast to the IL-6 signal transducer gp130, which has been previously shown to recruit SOCS3 to one of its phosphotyrosine residues (Y759), peptide precipitation experiments suggest that SOCS3 does not interact with phosphorylated tyrosine motifs of the IL-10R. Taken together, different sensitivities of IL-10 and IL-6 signaling toward mechanisms that inhibit the Janus kinase/STAT pathway define an important mechanism that contributes to the different anti-inflammatory potencies of these two cytokines.
authors.affiliation: Institut für Biochemie and Klinik und Lehrstuhl für Anästhesiologie, Universitätsklinikum RWTH Aachen, Aachen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Niemand
authors.forename: Ariane
authors.initials: A
authors.lastname: Nimmesgern
authors.forename: Serge
authors.initials: S
authors.lastname: Haan
authors.forename: Patrick
authors.initials: P
authors.lastname: Fischer
authors.forename: Fred
authors.initials: F
authors.lastname: Schaper
authors.forename: Rolf
authors.initials: R
authors.lastname: Rossaint
authors.forename: Peter C
authors.initials: PC
authors.lastname: Heinrich
authors.forename: Gerhard
authors.initials: G
authors.lastname: Müller-Newen
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D004789:Enzyme Activation / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D025461:Feedback, Physiological / Q000276:immunology; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000494:pharmacology; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000502:physiology*; D015850:Interleukin-6 / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000276:immunology; D008264:Macrophages / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D014176:Protein Biosynthesis; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011506:Proteins / Q000502:physiology*; D012097:Repressor Proteins; D050796:STAT3 Transcription Factor; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D000093242:Interleukin-6 Inhibitors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D016753:Interleukin-10; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; D011506:Proteins; D012097:Repressor Proteins; D050796:STAT3 Transcription Factor; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D013755:Tetradecanoylphorbol Acetate; D015534:Trans-Activators; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D000093242:Interleukin-6 Inhibitors; C106644:SOCS3 protein, human; C494086:STAT3 protein, human; C516724:PTPN11 protein, human