IFN-γ attenuates hypoxia-inducible factor (HIF) activity in intestinal epithelial cells through transcriptional repression of HIF-1β

J Immunol. 2011 Feb 1;186(3):1790-8. doi: 10.4049/jimmunol.1001442. Epub 2011 Jan 3.

Abstract

Numerous studies have revealed that hypoxia and inflammation occur coincidentally in mucosal disorders, such as inflammatory bowel disease. During inflammation, epithelial-expressed hypoxia-inducible factor (HIF) serves an endogenously protective function. In this study, we sought to explore how mucosal immune responses influence HIF-dependent end points. Guided by a screen of relevant inflammatory mediators, we identified IFN-γ as a potent repressor of HIF-dependent transcription in human intestinal epithelial cells. Analysis of HIF levels revealed that HIF-1β, but not HIF-1α, is selectively repressed by IFN-γ in a JAK-dependent manner. Cloning and functional analysis of the HIF-1β promoter identified a prominent region for IFN-γ-dependent repression. Further studies revealed that colonic IFN-γ and HIF-1β levels were inversely correlated in a murine colitis model. Taken together, these studies demonstrated that intestinal epithelial HIF is attenuated by IFN-γ through transcriptional repression of HIF-1β. These observations are relevant to the pathophysiology of colitis (i.e., that loss of HIF signaling during active inflammation may exacerbate disease pathogenesis).

Publication types

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

MeSH terms

  • Animals
  • Aryl Hydrocarbon Receptor Nuclear Translocator / antagonists & inhibitors*
  • Aryl Hydrocarbon Receptor Nuclear Translocator / genetics*
  • Aryl Hydrocarbon Receptor Nuclear Translocator / physiology
  • Caco-2 Cells
  • Cell Line, Tumor
  • Cells, Cultured
  • Cloning, Molecular
  • Colitis / enzymology
  • Colitis / immunology*
  • Colitis / pathology
  • Dextran Sulfate / toxicity
  • Disease Models, Animal
  • Female
  • Humans
  • Inflammation Mediators / antagonists & inhibitors
  • Inflammation Mediators / physiology
  • Interferon-gamma / physiology*
  • Intestinal Mucosa / enzymology
  • Intestinal Mucosa / immunology*
  • Intestinal Mucosa / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Procollagen-Proline Dioxygenase / physiology
  • Repressor Proteins / physiology*
  • Signal Transduction / immunology

Substances

  • Inflammation Mediators
  • Repressor Proteins
  • Aryl Hydrocarbon Receptor Nuclear Translocator
  • Interferon-gamma
  • Dextran Sulfate
  • Procollagen-Proline Dioxygenase