Effect of chemical stabilizers of hypoxia-inducible factors on early lung development

Am J Physiol Lung Cell Mol Physiol. 2007 Sep;293(3):L557-67. doi: 10.1152/ajplung.00486.2006. Epub 2007 Jun 1.


Low oxygen stimulates pulmonary vascular development and airway branching and involves hypoxia-inducible factor (HIF). HIF is stable and initiates expression of angiogenic factors under hypoxia, whereas normoxia triggers hydroxylation of the HIF-1alpha subunit by prolyl hydroxylases (PHDs) and subsequent degradation. Herein, we investigated whether chemical stabilization of HIF-1alpha under normoxic (20% O(2)) conditions would stimulate vascular growth and branching morphogenesis in early lung explants. Tie2-LacZ (endothelial LacZ marker) mice were used for visualization of the vasculature. Embryonic day 11.5 (E11.5) lung buds were dissected and cultured in 20% O(2) in the absence or presence of cobalt chloride (CoCl(2), a hypoxia mimetic), dimethyloxalylglycine (DMOG; a nonspecific inhibitor of PHDs), or desferrioxamine (DFO; an iron chelator). Vascularization was assessed by X-gal staining, and terminal buds were counted. The fine vascular network surrounding the developing lung buds seen in control explants disappeared in CoCl(2)- and DFO-treated explants. Also, epithelial branching was reduced in the explants treated with CoCl(2) and DFO. In contrast, DMOG inhibited branching but stimulated vascularization. Both DFO and DMOG increased nuclear HIF-1alpha protein levels, whereas CoCl(2) had no effect. Since HIF-1alpha induces VEGF expression, the effect of SU-5416, a potent VEGF receptor (VEGFR) blocker, on early lung development was also investigated. Inhibition of VEGFR2 signaling in explants maintained under hypoxic (2% O(2)) conditions completely abolished vascularization and slightly decreased epithelial branching. Taken together, the data suggest that DMOG stabilization of HIF-1alpha during early development leads to a hypervascular lung and that airway branching proceeds without the vasculature, albeit at a slower rate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids, Dicarboxylic / pharmacology*
  • Animals
  • Chlorides
  • Cobalt / pharmacology*
  • Deferoxamine / pharmacology*
  • Dose-Response Relationship, Drug
  • Embryo, Mammalian / cytology
  • Embryo, Mammalian / drug effects
  • Epithelial Cells / cytology
  • Ferric Compounds / pharmacology
  • Hypoxia-Inducible Factor 1 / metabolism*
  • In Vitro Techniques
  • Indoles / pharmacology
  • Lung / drug effects*
  • Lung / embryology*
  • Mice
  • Morphogenesis / drug effects
  • Neovascularization, Physiologic / drug effects
  • Pyrroles / pharmacology
  • Signal Transduction / drug effects
  • Vascular Endothelial Growth Factor Receptor-2 / antagonists & inhibitors


  • Amino Acids, Dicarboxylic
  • Chlorides
  • Ferric Compounds
  • Hypoxia-Inducible Factor 1
  • Indoles
  • Pyrroles
  • Cobalt
  • Semaxinib
  • Vascular Endothelial Growth Factor Receptor-2
  • cobaltous chloride
  • Deferoxamine
  • ferric chloride
  • oxalylglycine