title: Differential control of Mincle-dependent cord factor recognition and macrophage responses by the transcription factors C/EBPβ and HIF1α.
abstract: Trehalose-6,6-dimycolate (TDM), the mycobacterial cord factor, and its synthetic analog Trehalose-6,6-dibehenate (TDB) bind to the C-type lectin receptors macrophage-inducible C-type lectin (Mincle) and Mcl to activate macrophages. Genetically, the transcriptional response to TDB/TDM has been defined to require FcRγ-Syk-Card9 signaling. However, TDB/TDM-triggered kinase activation has not been studied well, and it is largely unknown which transcriptional regulators bring about inflammatory gene expression. In this article, we report that TDB/TDM caused only weak Syk-phosphorylation in resting macrophages, consistent with low basal Mincle expression. However, LPS-priming caused MYD88-dependent upregulation of Mincle, resulting in enhanced TDB/TDM-induced kinase activation and more rapid inflammatory gene expression. TLR-induced Mincle expression partially circumvented the requirement for Mcl in the response to TDB/TDM. To dissect transcriptional responses to TDB/TDM, we mined microarray data and identified early growth response (Egr) family transcription factors as direct Mincle target genes, whereas upregulation of Cebpb and Hif1a required new protein synthesis. Macrophages and dendritic cells lacking C/EBPβ showed nearly complete abrogation of TDB/TDM responsiveness, but also failed to upregulate Mincle. Retroviral rescue of Mincle expression in Cebpb-deficient cells restored induction of Egr1, but not of G-CSF. This pattern of C/EBPβ dependence was also observed after stimulation with the Dectin-1 ligand Curdlan. Inducible expression of hypoxia-inducible factor 1α (HIF1α) also required C/EBPβ. In turn, HIF1α was not required for Mincle expression, kinase activation, and Egr1 or Csf3 expression, but critically contributed to NO production. Taken together, we identify C/EBPβ as central hub in Mincle expression and inflammatory gene induction, whereas HIF1α controls Nos2 expression. C/EBPβ also connects TLR signals to cord factor responsiveness through MYD88-dependent upregulation of Mincle.
authors.affiliation: Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany;
authors.forename: Hanne
authors.initials: H
authors.lastname: Schoenen
authors.affiliation: Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany;
authors.forename: Alexandra
authors.initials: A
authors.lastname: Huber
authors.affiliation: Oncology and Immunology Section, Department of Surgery, Oncology and Gastroenterology, University of Padua, 35128, Padua, Italy;
authors.forename: Nada
authors.initials: N
authors.lastname: Sonda
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany; Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany;
authors.forename: Stephanie
authors.initials: S
authors.lastname: Zimmermann
authors.affiliation: Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; Institut für Klinische Mikrobiologie und Hygiene, Universitätsklinikum Regensburg, 93053 Regensburg, Germany; and.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Jantsch
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany; Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany;
authors.forename: Bernd
authors.initials: B
authors.lastname: Lepenies
authors.affiliation: Immunology Section, Department of Pathology, Verona University Hospital, University of Verona, 37134 Verona, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Bronte
authors.affiliation: Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; roland.lang@uk-erlangen.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Lang
mesh_terms: D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000276:immunology*; D003311:Cord Factors / Q000737:chemistry / Q000494:pharmacology*; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000276:immunology; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D016179:Granulocyte Colony-Stimulating Factor / Q000276:immunology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000276:immunology*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D009169:Mycobacterium tuberculosis / Q000737:chemistry*; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000276:immunology; D009569:Nitric Oxide / Q000235:genetics / Q000276:immunology; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000276:immunology; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology; D000072377:Syk Kinase; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology; D015854:Up-Regulation / Q000187:drug effects* / Q000235:genetics / Q000276:immunology; D047071:beta-Glucans / Q000737:chemistry / Q000494:pharmacology; D000099181:Dectin-1
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D003311:Cord Factors; D051766:Early Growth Response Protein 1; D016179:Granulocyte Colony-Stimulating Factor; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D047908:Intracellular Signaling Peptides and Proteins; D037181:Lectins, C-Type; D008565:Membrane Proteins; D053594:Myeloid Differentiation Factor 88; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; D051193:Toll-Like Receptors; D047071:beta-Glucans; D000099181:Dectin-1; C545013:Cebpb protein, mouse; C113583:Clecsf8 protein, mouse; C486109:Egr1 protein, mouse; C497443:Hif1a protein, mouse; C507780:Myd88 protein, mouse; C038459:curdlan; C496317:Nos2 protein, mouse; C000606897:Syk protein, mouse