Cellular and developmental control of O2 homeostasis by hypoxia-inducible factor 1α

  1. Narayan V. Iyer1,5,
  2. Lori E. Kotch1,5,
  3. Faton Agani1,
  4. Sandra W. Leung1,
  5. Erik Laughner1,
  6. Roland H. Wenger2,
  7. Max Gassmann2,
  8. John D. Gearhart3,
  9. Ann M. Lawler3,
  10. Aimee Y. Yu1, and
  11. Gregg L. Semenza1,4
  1. 1Center for Medical Genetics, Departments of Pediatrics and Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-3914 USA; 2Institute of Physiology, University of Zurich-Irchel, 8057 Zurich, Switzerland; 3Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 USA

Abstract

Hypoxia is an essential developmental and physiological stimulus that plays a key role in the pathophysiology of cancer, heart attack, stroke, and other major causes of mortality. Hypoxia-inducible factor 1 (HIF-1) is the only known mammalian transcription factor expressed uniquely in response to physiologically relevant levels of hypoxia. We now report that in Hif1a −/−embryonic stem cells that did not express the O2-regulated HIF-1α subunit, levels of mRNAs encoding glucose transporters and glycolytic enzymes were reduced, and cellular proliferation was impaired. Vascular endothelial growth factor mRNA expression was also markedly decreased in hypoxicHif1a −/− embryonic stem cells and cystic embryoid bodies. Complete deficiency of HIF-1α resulted in developmental arrest and lethality by E11 ofHif1a −/− embryos that manifested neural tube defects, cardiovascular malformations, and marked cell death within the cephalic mesenchyme. InHif1a +/+ embryos, HIF-1α expression increased between E8.5 and E9.5, coincident with the onset of developmental defects and cell death inHif1a −/− embryos. These results demonstrate that HIF-1α is a master regulator of cellular and developmental O2 homeostasis.

Keywords

Footnotes

  • 4 Corresponding author.

  • 5 These authors contributed equally to this work.

  • E-MAIL gsemenza{at}gwgate1.jhmi.jhu.edu; FAX (410) 955-0484.

    • Received October 2, 1997.
    • Accepted November 18, 1997.
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