title: Induction of hypoxia inducible factor (HIF-1α) in rat kidneys by iron chelation with the hydroxypyridinone, CP94.
abstract: 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.
authors.affiliation: Laboratory of Biochemistry and Vascular Biology, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Jin Hyen
authors.initials: JH
authors.lastname: Baek
authors.forename: Chad E N
authors.initials: CE
authors.lastname: Reiter
authors.forename: Dominador J
authors.initials: DJ
authors.lastname: Manalo
authors.forename: Paul W
authors.initials: PW
authors.lastname: Buehler
authors.forename: Robert C
authors.initials: RC
authors.lastname: Hider
authors.forename: Abdu I
authors.initials: AI
authors.lastname: Alayash
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002460:Cell Line; D003035:Cobalt / Q000494:pharmacology; D000077543:Deferiprone; D003676:Deferoxamine / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D006900:Hydroxylation / Q000187:drug effects; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D007502:Iron Chelating Agents / Q000008:administration & dosage / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011728:Pyridones / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017262:Siderophores / Q000494:pharmacology
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007502:Iron Chelating Agents; D011728:Pyridones; D017262:Siderophores; C068543:1,2-diethyl-3-hydroxypyridin-4-one; D000077543:Deferiprone; D003035:Cobalt; D011393:Procollagen-Proline Dioxygenase; C018021:cobaltous chloride; D003676:Deferoxamine