title: STAT3 regulates NF-kappaB recruitment to the IL-12p40 promoter in dendritic cells.
abstract: Interleukin-10-deficient (IL-10(-/-)) mice develop an IL-12-mediated intestinal inflammation in the absence of endogenous IL-10. The molecular mechanisms of the dysregulated IL-12 responses in IL-10(-/-) mice are poorly understood. In this study, we investigated the role of nuclear factor-kappa B (NF-kappaB) and signal transducers and activators of transcription 3 (STAT3) in lipopolysaccharide (LPS)-induced IL-12p40 gene expression in bone marrow derived-dendritic cells (BMDCs) isolated from wild-type (WT) and IL-10(-/-) mice. We report higher IL-12p40 mRNA accumulation and protein secretion in LPS-stimulated BMDCs isolated from IL-10(-/-) compared with WT mice. LPS-induced NF-kappaB signaling is similar in IL-10(-/-) and WT BMDCs as measured by IkappaBalpha phosphorylation and degradation, RelA phosphorylation and nuclear translocation, and NF-kappaB transcriptional activity, with no down-regulatory effects of exogenous IL-10. Chromatin immunoprecipitation demonstrated enhanced NF-kappaB (cRel, RelA) binding to the IL-12p40 promoter in IL-10(-/-) but not WT BMDCs. Interestingly, LPS induced STAT3 phosphorylation in WT but not IL-10(-/-) BMDCs, a process blocked by IL-10 receptor blocking antibody. Adenoviral gene delivery of a constitutively active STAT3 but not control green fluorescence protein (GFP) virus blocked LPS-induced IL-12p40 gene expression and cRel recruitment to the IL-12p40 promoter. In conclusion, dysregulated LPS-induced IL-12p40 gene expression in IL-10(-/-) mice is due to enhanced NF-kappaB recruitment to the IL-12p40 promoter in the absence of activated STAT3.
authors.affiliation: Center for Gastrointestinal Biology and Diseases, University of North Carolina at Chapel Hill, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Hoentjen
authors.forename: R Balfour
authors.initials: RB
authors.lastname: Sartor
authors.forename: Michitaka
authors.initials: M
authors.lastname: Ozaki
authors.forename: Christian
authors.initials: C
authors.lastname: Jobin
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D003713:Dendritic Cells / Q000378:metabolism / Q000502:physiology*; D015870:Gene Expression / Q000187:drug effects / Q000276:immunology; D020573:Genes, rel / Q000502:physiology; D016753:Interleukin-10 / Q000235:genetics; D018664:Interleukin-12 / Q000235:genetics* / Q000378:metabolism; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000502:physiology; D021122:Protein Subunits / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides; D016328:NF-kappa B; D021122:Protein Subunits; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D018664:Interleukin-12