Induction of hypoxia inducible factor (HIF-1α) in rat kidneys by iron chelation with the hydroxypyridinone, CP94

Biochim Biophys Acta. Apr-Jun 2011;1809(4-6):262-8. doi: 10.1016/j.bbagrm.2011.04.010. Epub 2011 May 1.


Hypoxia inducible factor (HIF-1α) is a master regulator of tissue adaptive responses to hypoxia whose stability is controlled by an iron containing prolyl hydroxylase domain (PHD) protein. A catalytic redox cycle in the PHD's iron center that results in the formation of a ferryl (Fe(+4)) intermediate has been reported to be responsible for the hydroxylation and subsequent degradation of HIF-1α under normoxia. We show that induction of HIF-1α in rat kidneys can be achieved by iron reduction by the hydroxypyridin-4 one (CP94), an iron chelator administered intraperitoneally in rats. The extent of HIF protein stabilization as well as the expression of HIF target genes, including erythropoietin (EPO), in kidney tissues was comparable to those induced by known inhibitors of the PHD enzyme, such as desferrioxamine (DFO) and cobalt chloride (CoCl(2)). In human kidney cells and in vitro PHD activity assay, we were able to show that the HIF-1α protein can be stabilized by addition of CP94. This appears to inactivate PHD; and thus prevents the hydroxylation of HIF-1α. In conclusion, we have identified the inhibition of iron-binding pocket of PHD as an underlying mechanism of HIF induction in vivo and in vitro by a bidentate hydroxypyridinone.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Blotting, Western
  • Cell Line
  • Cobalt / pharmacology
  • Deferiprone
  • Deferoxamine / pharmacology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Gene Expression Regulation / drug effects
  • HEK293 Cells
  • Humans
  • Hydroxylation / drug effects
  • Hypoxia
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Injections, Intraperitoneal
  • Iron Chelating Agents / administration & dosage
  • Iron Chelating Agents / pharmacology*
  • Kidney / drug effects*
  • Kidney / metabolism
  • Procollagen-Proline Dioxygenase / antagonists & inhibitors
  • Procollagen-Proline Dioxygenase / genetics
  • Procollagen-Proline Dioxygenase / metabolism
  • Pyridones / administration & dosage
  • Pyridones / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Reverse Transcriptase Polymerase Chain Reaction
  • Siderophores / pharmacology


  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Iron Chelating Agents
  • Pyridones
  • Siderophores
  • 1,2-diethyl-3-hydroxypyridin-4-one
  • Deferiprone
  • Cobalt
  • Procollagen-Proline Dioxygenase
  • cobaltous chloride
  • Deferoxamine