title: Transcriptional regulation of tristetraprolin by NF-κB signaling in LPS-stimulated macrophages.
abstract: Lipopolysaccharide (LPS) treatment causes the marked changes of gene expression in macrophages. Tristetraprolin (TTP), which is an mRNA-destabilizing protein that negatively regulates the expression of pro-inflammatory mediators, is induced by LPS. To delineate the molecular mechanism of LPS-stimulated TTP expression, several inhibitors blocking different signaling pathways were used initially. We observed that inhibitors of the NF-κB signaling pathway could down-regulate the TTP expression during LPS-induction. Consistently, TTP expression was increased upon recombinant TNFα stimulation which activates NF-κB signaling. The 5' regulatory region of zfp36 gene spanning from -2 k to +50 was isolated, which contained a putative NF-κB-binding site located in -1859 to -1850. Analysis of luciferase reporter activity driven by a serial 5'-deletion of TTP promoter showed that NF-κB inhibitor-mediated suppression of LPS or TNFα induced activity was through the predicted κB-binding sites. When the NF-κB-binding site was mutated, the TTP promoter decreased its response to the ectopic expression of NF-κB. Physical interaction analysis including oligonucleotides competition, gel shift and chromatin immunoprecipitation assays demonstrated that NF-κB activated by LPS or TNFα bound to the TTP promoter specifically. These results suggested that during LPS stimulation, NF-κB signaling were activated to regulate the transcription of TTP mRNA.
authors.affiliation: Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Chen
authors.forename: Yu-Wun
authors.initials: YW
authors.lastname: Jiang
authors.forename: Yu-Lun
authors.initials: YL
authors.lastname: Su
authors.forename: Sheng-Chung
authors.initials: SC
authors.lastname: Lee
authors.forename: Mau-Sun
authors.initials: MS
authors.lastname: Chang
authors.forename: Ching-Jin
authors.initials: CJ
authors.lastname: Chang
mesh_terms: D000818:Animals; D015536:Down-Regulation; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008070:Lipopolysaccharides / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics*; D041681:NIH 3T3 Cells; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014158:Transcription, Genetic; D051816:Tristetraprolin / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D051816:Tristetraprolin; D014409:Tumor Necrosis Factor-alpha