title: CpG-B oligodeoxynucleotides inhibit TLR-dependent and -independent induction of type I IFN in dendritic cells.
abstract: CpG oligodeoxynucleotides (ODNs) signal through TLR9 to induce type I IFN (IFN-alphabeta) in dendritic cells (DCs). CpG-A ODNs are more efficacious than CpG-B ODNs for induction of IFN-alphabeta. Because IFN-alphabeta may contribute to autoimmunity, it is important to identify mechanisms to inhibit induction of IFN-alphabeta. In our studies, CpG-B ODN inhibited induction of IFN-alphabeta by CpG-A ODN, whereas induction of TNF-alpha and IL-12p40 by CpG-A ODN was not affected. CpG-B inhibition of IFN-alphabeta was observed in FLT3 ligand-induced murine DCs, purified murine myeloid DCs, plasmacytoid DCs, and human PBMCs. CpG-B ODN inhibited induction of IFN-alphabeta by agonists of multiple receptors, including MyD88-dependent TLRs (CpG-A ODN signaling via TLR9, or R837 or Sendai virus signaling via TLR7) and MyD88-independent receptors (polyinosinic:polycytidylic acid signaling via TLR3 or ds break-DNA signaling via a cytosolic pathway). CpG-B ODN did not inhibit the IFN-alphabeta positive feedback loop second-wave IFN-alphabeta, because IFN-alphabeta-induced expression of IFN-alphabeta was unaffected, and CpG-B inhibition of IFN-alphabeta was manifested in IFN-alphabetaR(-/-) DCs, which lack the positive feedback mechanism. Rather, CpG-B ODN inhibited early TLR-induced first wave IFN-alpha4 and IFN-beta. Chromatin immunoprecipitation revealed that association of IFN regulatory factor 1 with the IFN-alpha4 and IFN-beta promoters was induced by CpG-A ODN but not CpG-B ODN. Moreover, CpG-A-induced association of IFN regulatory factor 1 with these promoters was inhibited by CpG-B ODN. Our studies demonstrate a novel mechanism of transcriptional regulation of first-wave IFN-alphabeta that selectively inhibits induction of IFN-alphabeta downstream of multiple receptors and may provide targets for future therapeutic inhibition of IFN-alphabeta expression in vivo.
authors.affiliation: Department of Pathology, Case Western Reserve University, University Hospitals Case Medical Center, Cleveland, OH 44106, USA.
authors.forename: Yi C
authors.initials: YC
authors.lastname: Liu
authors.forename: Reginald C
authors.initials: RC
authors.lastname: Gray
authors.forename: Gareth A D
authors.initials: GA
authors.lastname: Hardy
authors.forename: John
authors.initials: J
authors.lastname: Kuchtey
authors.forename: Derek W
authors.initials: DW
authors.lastname: Abbott
authors.forename: Steven N
authors.initials: SN
authors.lastname: Emancipator
authors.forename: Clifford V
authors.initials: CV
authors.lastname: Harding
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007370:Interferon Type I / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000276:immunology* / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology*; D014158:Transcription, Genetic
chemical_list: D000276:Adjuvants, Immunologic; C408982:CPG-oligonucleotide; D007370:Interferon Type I; D009838:Oligodeoxyribonucleotides