Transcriptional regulation of tristetraprolin by NF-κB signaling in LPS-stimulated macrophages

Mol Biol Rep. 2013 Apr;40(4):2867-77. doi: 10.1007/s11033-012-2302-8. Epub 2012 Dec 1.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Down-Regulation
  • Gene Expression Regulation / drug effects
  • Humans
  • Lipopolysaccharides / toxicity
  • Macrophages / drug effects
  • Macrophages / metabolism*
  • Mice
  • NF-kappa B / genetics*
  • NIH 3T3 Cells
  • Promoter Regions, Genetic
  • RNA, Messenger / genetics
  • Signal Transduction / drug effects
  • Transcription, Genetic*
  • Tristetraprolin / genetics*
  • Tumor Necrosis Factor-alpha / genetics

Substances

  • Lipopolysaccharides
  • NF-kappa B
  • RNA, Messenger
  • Tristetraprolin
  • Tumor Necrosis Factor-alpha