A post-transcriptional pathway represses monocyte VEGF-A expression and angiogenic activity

EMBO J. 2007 Jul 25;26(14):3360-72. doi: 10.1038/sj.emboj.7601774. Epub 2007 Jul 5.

Abstract

Monocyte-macrophage activation by interferon (IFN)-gamma is a key initiating event in inflammation. Usually, the macrophage response is self-limiting and inflammation resolves. Here, we describe a mechanism by which IFN-gamma contributes to inflammation resolution by suppressing expression of vascular endothelial growth factor-A (VEGF-A), a macrophage product that stimulates angiogenesis during chronic inflammation and tumorigenesis. VEGF-A was identified as a candidate target of the IFN-gamma-activated inhibitor of translation (GAIT) complex by bioinformatic analysis, and experimentally validated by messenger RNA-protein interaction studies. Although IFN-gamma induced persistent VEGF-A mRNA expression, translation was suppressed by delayed binding of the GAIT complex to a specific element delineated in the 3'UTR. Translational silencing resulted in decreased VEGF-A synthesis and angiogenic activity. Our results describe a unique anti-inflammatory pathway in which IFN-gamma-dependent induction of VEGF-A mRNA is translationally silenced by the same stimulus, and they suggest the GAIT system directs a post-transcriptional operon that contributes to inflammation resolution.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3' Untranslated Regions / metabolism
  • Animals
  • Base Sequence
  • Cattle
  • Gene Expression Regulation / drug effects
  • Gene Silencing / drug effects
  • Humans
  • Interferon-gamma / pharmacology
  • Molecular Sequence Data
  • Monocytes / cytology
  • Monocytes / drug effects
  • Monocytes / metabolism*
  • Neovascularization, Physiologic* / drug effects
  • Nucleic Acid Conformation / drug effects
  • Protein Biosynthesis / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Regulatory Sequences, Nucleic Acid / genetics
  • Transcription, Genetic* / drug effects
  • Vascular Endothelial Growth Factor A / genetics*
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • 3' Untranslated Regions
  • RNA, Messenger
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Interferon-gamma