Bcl-6 and NF-kappaB cistromes mediate opposing regulation of the innate immune response

Genes Dev. 2010 Dec 15;24(24):2760-5. doi: 10.1101/gad.1998010. Epub 2010 Nov 24.

Abstract

In the macrophage, toll-like receptors (TLRs) are key sensors that trigger signaling cascades to activate inflammatory programs via the NF-κB gene network. However, the genomic network targeted by TLR/NF-κB activation and the molecular basis by which it is restrained to terminate activation and re-establish quiescence is poorly understood. Here, using chromatin immunoprecipitation sequencing (ChIP-seq), we define the NF-κB cistrome, which is comprised of 31,070 cis-acting binding sites responsive to lipopolysaccharide (LPS)-induced signaling. In addition, we demonstrate that the transcriptional repressor B-cell lymphoma 6 (Bcl-6) regulates nearly a third of the Tlr4-regulated transcriptome, and that 90% of the Bcl-6 cistrome is collapsed following Tlr4 activation. Bcl-6-deficient macrophages are acutely hypersensitive to LPS and, using comparative ChIP-seq analyses, we found that the Bcl-6 and NF-κB cistromes intersect, within nucleosomal distance, at nearly half of Bcl-6-binding sites in stimulated macrophages to promote opposing epigenetic modifications of the local chromatin. These results reveal a genomic strategy for controlling the innate immune response in which repressive and inductive cistromes establish a dynamic balance between macrophage quiescence and activation via epigenetically marked cis-regulatory elements.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Cells, Cultured
  • DNA-Binding Proteins / genetics*
  • Enhancer Elements, Genetic / immunology*
  • Epigenesis, Genetic
  • Gene Expression Regulation / immunology*
  • Immunity, Innate / genetics*
  • Lipopolysaccharides / pharmacology
  • Macrophages / immunology*
  • Mice
  • NF-kappa B / genetics*
  • Proto-Oncogene Proteins c-bcl-6
  • Toll-Like Receptor 4 / genetics

Substances

  • BCL6 protein, human
  • DNA-Binding Proteins
  • Lipopolysaccharides
  • NF-kappa B
  • Proto-Oncogene Proteins c-bcl-6
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4