title: Imbalanced gp130-dependent signaling in macrophages alters macrophage colony-stimulating factor responsiveness via regulation of c-fms expression.
abstract: The mechanisms by which interleukin-6 (IL-6) family cytokines, which utilize the common receptor signaling subunit gp130, influence monocyte/macrophage development remain unclear. Here we have utilized macrophages devoid of either gp130-dependent STAT1/3 (gp130(Delta STAT/Delta STAT)) or extracellular signal-regulated kinases 1 and 2 (ERK1/2) mitogen-activated protein (MAP) kinase (gp130(Y757F/Y757F)) activation to assess the individual contribution of each pathway to macrophage formation. While the inhibition by IL-6 of macrophage colony-stimulating factor (M-CSF)-induced colony formation observed in gp130(wt/wt) mice was abolished in gp130(Delta STAT/Delta STAT) mice, inhibition of macrophage colony formation was enhanced in gp130(Y757F/Y757F) mice. In gp130(Delta STAT/Delta STAT) bone marrow-derived macrophages (BMMs), both IL-6- and M-CSF-induced ERK1/2 tyrosine phosphorylation was enhanced. By contrast, tyrosine phosphorylation of ERK1/2 in response to M-CSF was reduced in gp130(Y757F/Y757F) BMMs, and the pattern of ERK1/2 activation in gp130 mutant BMMs correlated with their opposing responsiveness to M-CSF-induced proliferation. When compared to the level of expression in gp130(wt/wt) BMMs, c-fms expression was elevated in gp130(Delta STAT/Delta STAT) BMMs but reduced in gp130(Y757F/Y757F) BMMs. Finally, an ERK1/2 inhibitor suppressed M-CSF-induced BMM proliferation, and this result corresponded to a reduction in c-fms expression. Collectively, these results provide a functional and causal correlation between gp130-dependent ERK MAP kinase signaling and c-fms gene activation, a finding that provides a potential mechanism underlying the inhibition of M-CSF-dependent macrophage development by IL-6 family cytokines in mice.
authors.affiliation: Ludwig Institute for Cancer Research, Colon Molecular and Cell Biology Laboratory, Parkville, Victoria, Australia. Brendan.Jenkins@ludwig.edu.au
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Jenkins
authors.forename: Dianne
authors.initials: D
authors.lastname: Grail
authors.forename: Melissa
authors.initials: M
authors.lastname: Inglese
authors.forename: Cathy
authors.initials: C
authors.lastname: Quilici
authors.forename: Steven
authors.initials: S
authors.lastname: Bozinovski
authors.forename: Peter
authors.initials: P
authors.lastname: Wong
authors.forename: Matthias
authors.initials: M
authors.lastname: Ernst
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D050822:Cytokine Receptor gp130; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D016236:Genes, fms / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D015703:Antigens, CD; D004268:DNA-Binding Proteins; C494199:IL6ST protein, human; C494200:Il6st protein, mouse; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D050822:Cytokine Receptor gp130; D016173:Macrophage Colony-Stimulating Factor; D020928:Mitogen-Activated Protein Kinases; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse