NF-κB- and AP-1-mediated DNA looping regulates osteopontin transcription in endotoxin-stimulated murine macrophages

J Immunol. 2011 Mar 1;186(5):3173-9. doi: 10.4049/jimmunol.1003626. Epub 2011 Jan 21.

Abstract

Osteopontin (OPN) is expressed by various immune cells and modulates both innate and adaptive immune responses. However, the molecular mechanisms that control opn gene expression, especially at the chromatin level, remain largely unknown. We have previously demonstrated many specific cis- and trans-regulatory elements that determine the extent of endotoxin (LPS)-mediated induction of OPN synthesis in murine macrophages. In the present study, we confirm that NF-κB also plays an important role in the setting of LPS-stimulated OPN expression through binding to a distal regulatory element. Importantly, we demonstrate that LPS stimulates chromosomal loops in the OPN promoter between NF-κB binding site and AP-1 binding site using chromosome conformation capture technology. The crucial role of NF-κB and AP-1 in LPS-stimulated DNA looping was confirmed, as small interfering RNA knock-down of NF-κB p65 and AP-1 c-Jun exhibited decreased levels of DNA looping. Furthermore, we demonstrate that p300 can form a complex with NF-κB and AP-1 and is involved in DNA looping and LPS-induced OPN expression. Therefore, we have identified an essential mechanism to remodel the local chromatin structures and spatial conformations to regulate LPS-induced OPN expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • DNA / antagonists & inhibitors
  • DNA / chemistry*
  • DNA / physiology
  • Extracellular Signal-Regulated MAP Kinases / biosynthesis
  • Gene Expression Regulation / immunology
  • I-kappa B Kinase / biosynthesis
  • Lipopolysaccharides / physiology*
  • Macrophage Activation / genetics*
  • Macrophage Activation / immunology
  • Mice
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / genetics
  • NF-kappa B / physiology*
  • Nucleic Acid Conformation*
  • Osteopontin / biosynthesis
  • Osteopontin / genetics*
  • Osteopontin / metabolism
  • Protein Binding / genetics
  • Protein Binding / immunology
  • Proto-Oncogene Proteins c-jun / genetics
  • Proto-Oncogene Proteins c-jun / pharmacology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / pharmacology
  • Transcription Factor AP-1 / chemistry
  • Transcription Factor AP-1 / genetics
  • Transcription Factor AP-1 / physiology*
  • Transcription Factor RelA / antagonists & inhibitors
  • Transcription, Genetic / immunology*
  • p300-CBP Transcription Factors / metabolism

Substances

  • Lipopolysaccharides
  • NF-kappa B
  • Proto-Oncogene Proteins c-jun
  • RNA, Small Interfering
  • Rela protein, mouse
  • Transcription Factor AP-1
  • Transcription Factor RelA
  • Osteopontin
  • DNA
  • p300-CBP Transcription Factors
  • I-kappa B Kinase
  • Extracellular Signal-Regulated MAP Kinases