Iron-regulatory proteins limit hypoxia-inducible factor-2α expression in iron deficiency

Hypoxia stimulates erythropoiesis, the major iron-utilization pathway. We report the discovery of a conserved, functional iron-responsive element (IRE) in the 5′ untranslated region of the messenger RNA encoding endothelial PAS domain protein-1, EPAS1 (also called hypoxia-inducible factor-2α, HIF2α). Via this IRE, iron regulatory protein binding controls EPAS1 mRNA translation in response to cellular iron availability. Our results uncover a regulatory link that permits feedback control between iron availability and the expression of a key transcription factor promoting iron utilization. They also show that an IRE that is structurally distinct from, for example, the ferritin mRNA IRE and that has been missed by in silico approaches, can mediate mechanistically similar responses.

[1]  Kai-Uwe Eckardt,et al.  The FASEB Journal express article 10.1096/fj.02-0445fje. Published online December 17, 2002. Widespread, hypoxia-inducible expression of HIF-2α in distinct cell populations of different organs , 2022 .

[2]  J. Richardson,et al.  HIF-2alpha regulates murine hematopoietic development in an erythropoietin-dependent manner. , 2005, Blood.

[3]  M. Hentze,et al.  Position is the critical determinant for function of iron-responsive elements as translational regulators , 1992, Molecular and cellular biology.

[4]  Rosa Bernardi,et al.  PML inhibits HIF-1alpha translation and neoangiogenesis through repression of mTOR. , 2006, Nature.

[5]  G. Semenza,et al.  Hypoxia Response Elements in the Aldolase A, Enolase 1, and Lactate Dehydrogenase A Gene Promoters Contain Essential Binding Sites for Hypoxia-inducible Factor 1* , 1996, The Journal of Biological Chemistry.

[6]  M. A. Morris,et al.  The HIF family member EPAS1/HIF-2alpha is required for normal hematopoiesis in mice. , 2003, Blood.

[7]  S. McKnight,et al.  Endothelial PAS domain protein 1 (EPAS1), a transcription factor selectively expressed in endothelial cells. , 1997, Genes & development.

[8]  D. Peet,et al.  Asparagine Hydroxylation of the HIF Transactivation Domain: A Hypoxic Switch , 2002, Science.

[9]  Y. Fujii‐Kuriyama,et al.  HLF/HIF‐2α is a key factor in retinopathy of prematurity in association with erythropoietin , 2003, The EMBO journal.

[10]  L. Gunaratnam,et al.  Silencing of epidermal growth factor receptor suppresses hypoxia-inducible factor-2-driven VHL-/- renal cancer. , 2005, Cancer research.

[11]  N. Gray,et al.  IRP-1 binding to ferritin mRNA prevents the recruitment of the small ribosomal subunit by the cap-binding complex eIF4F. , 1998, Molecular cell.

[12]  Y Fujii-Kuriyama,et al.  A novel bHLH-PAS factor with close sequence similarity to hypoxia-inducible factor 1alpha regulates the VEGF expression and is potentially involved in lung and vascular development. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[13]  D. Templeton,et al.  Effect of hypoxia on the binding and subcellular distribution of iron regulatory proteins , 2007, Molecular and Cellular Biochemistry.

[14]  K. Bridges,et al.  Hypoxia Alters Iron-regulatory Protein-1 Binding Capacity and Modulates Cellular Iron Homeostasis in Human Hepatoma and Erythroleukemia Cells* , 1999, The Journal of Biological Chemistry.

[15]  G. Goodall,et al.  Hypoxia-inducible Factor-1 (cid:1) mRNA Contains an Internal Ribosome Entry Site That Allows Efficient Translation during Normoxia and Hypoxia , 2022 .

[16]  N. Gray,et al.  Ribosomal Pausing and Scanning Arrest as Mechanisms of Translational Regulation from Cap-Distal Iron-Responsive Elements , 1999, Molecular and Cellular Biology.

[17]  N. Gray,et al.  Translational regulation of mammalian and Drosophila citric acid cycle enzymes via iron-responsive elements. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[18]  M. A. Morris,et al.  The HIF family member EPAS1/HIF-2α is required for normal hematopoiesis in mice , 2003 .

[19]  M. Gassmann,et al.  Oxygen(es) and the hypoxia-inducible factor-1. , 1997, Biological chemistry.

[20]  Brian Keith,et al.  Differential roles of hypoxia-inducible factor 1alpha (HIF-1alpha) and HIF-2alpha in hypoxic gene regulation. , 2003, Molecular and cellular biology.

[21]  R. Hammer,et al.  The hypoxia-responsive transcription factor EPAS1 is essential for catecholamine homeostasis and protection against heart failure during embryonic development. , 1998, Genes & development.

[22]  E. Debnam,et al.  Increased duodenal iron uptake and transfer in a rat model of chronic hypoxia is accompanied by reduced hepcidin expression , 2005, Gut.

[23]  R D Klausner,et al.  Identification of the iron-responsive element for the translational regulation of human ferritin mRNA. , 1987, Science.

[24]  K. Eckardt,et al.  Regulation of erythropoietin production , 2005, Contributions to nephrology.

[25]  G. Goodall,et al.  Hypoxia-inducible factor-1alpha mRNA contains an internal ribosome entry site that allows efficient translation during normoxia and hypoxia. , 2002, Molecular biology of the cell.

[26]  W. Risau,et al.  HRF, a putative basic helix-loop-helix-PAS-domain transcription factor is closely related to hypoxia-inducible factor-1α and developmentally expressed in blood vessels , 1997, Mechanisms of Development.

[27]  R D Klausner,et al.  Evidence that the pathway of transferrin receptor mRNA degradation involves an endonucleolytic cleavage within the 3′ UTR and does not involve poly(A) tail shortening. , 1994, The EMBO journal.

[28]  R. Eisenstein,et al.  Molecular control of vertebrate iron homeostasis by iron regulatory proteins. , 2006, Biochimica et biophysica acta.

[29]  Yuichi Makino,et al.  Regulation of the Hypoxia-inducible Transcription Factor 1α by the Ubiquitin-Proteasome Pathway* , 1999, The Journal of Biological Chemistry.

[30]  M. Muckenthaler,et al.  The deadenylating nuclease (DAN) is involved in poly(A) tail removal during the meiotic maturation of Xenopus oocytes , 1998, The EMBO journal.

[31]  Brian Keith,et al.  Differential Roles of Hypoxia-Inducible Factor 1α (HIF-1α) and HIF-2α in Hypoxic Gene Regulation , 2003, Molecular and Cellular Biology.

[32]  D. Birch,et al.  Retinal disease in mice lacking hypoxia-inducible transcription factor-2alpha. , 2005, Investigative ophthalmology & visual science.

[33]  C. Wykoff,et al.  The tumour suppressor protein VHL targets hypoxia-inducible factors for oxygen-dependent proteolysis , 1999, Nature.

[34]  V. Beneš,et al.  Standardization of protocols in cDNA microarray analysis. , 2003, Trends in biochemical sciences.

[35]  L. Poellinger,et al.  Signal transduction in hypoxic cells: inducible nuclear translocation and recruitment of theCBP/p300 coactivator by the hypoxia‐induciblefactor‐1α , 1998, The EMBO journal.

[36]  Rosa Bernardi,et al.  PML inhibits HIF-1α translation and neoangiogenesis through repression of mTOR , 2006, Nature.

[37]  Kai-Uwe Eckardt,et al.  Expression of hypoxia-inducible factor-1alpha and -2alpha in hypoxic and ischemic rat kidneys. , 2002, Journal of the American Society of Nephrology : JASN.

[38]  D. Haile,et al.  Role of the ferroportin iron-responsive element in iron and nitric oxide dependent gene regulation. , 2002, Blood cells, molecules & diseases.

[39]  Peter Bengert,et al.  Iron Regulation and the Cell Cycle , 2006, Journal of Biological Chemistry.

[40]  V. Erdmann,et al.  Differentiating the functional role of hypoxia‐inducible factor (HIF)‐1α and HIF‐2α (EPAS‐1) by the use of RNA interference: erythropoietin is a HIF‐2α target gene in Hep3B and Kelly cells , 2004 .

[41]  M. Hentze,et al.  Iron‐dependent regulation of the divalent metal ion transporter , 2001, FEBS letters.

[42]  E. Hanson,et al.  Hypoxia Post-translationally Activates Iron-regulatory Protein 2* , 1999, The Journal of Biological Chemistry.

[43]  H. Ryan,et al.  HIF-1 alpha is required for solid tumor formation and embryonic vascularization. , 1998, The EMBO journal.

[44]  N. Gray,et al.  Recombinant iron-regulatory factor functions as an iron-responsive-element-binding protein, a translational repressor and an aconitase. A functional assay for translational repression and direct demonstration of the iron switch. , 1993, European journal of biochemistry.

[45]  M. Hentze,et al.  Balancing Acts Molecular Control of Mammalian Iron Metabolism , 2004, Cell.

[46]  J. Peng,et al.  The transcription factor EPAS-1/hypoxia-inducible factor 2alpha plays an important role in vascular remodeling. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[47]  R D Klausner,et al.  A model for the structure and functions of iron-responsive elements. , 1988, Gene.

[48]  P. Carmeliet,et al.  Loss of HIF-2α and inhibition of VEGF impair fetal lung maturation, whereas treatment with VEGF prevents fatal respiratory distress in premature mice , 2002, Nature Medicine.

[49]  T. Rouault,et al.  Complete loss of iron regulatory proteins 1 and 2 prevents viability of murine zygotes beyond the blastocyst stage of embryonic development. , 2006, Blood cells, molecules & diseases.

[50]  M. Hentze,et al.  Generation of conditional alleles of the murine iron regulatory protein (IRP)‐1 and ‐2 genes , 2005, Genesis.

[51]  G. Semenza,et al.  Hypoxia-inducible factor 1: oxygen homeostasis and disease pathophysiology. , 2001, Trends in molecular medicine.

[52]  J. Hogenesch,et al.  Characterization of a Subset of the Basic-Helix-Loop-Helix-PAS Superfamily That Interacts with Components of the Dioxin Signaling Pathway* , 1997, The Journal of Biological Chemistry.

[53]  R. Eisenstein.  Iron regulatory proteins and the molecular control of mammalian iron metabolism. , 2000, Annual review of nutrition.

[54]  G. Semenza,et al.  Hypoxia-inducible factor 1 is a basic-helix-loop-helix-PAS heterodimer regulated by cellular O2 tension. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[55]  Christopher J. Schofield,et al.  Oxygen sensing by HIF hydroxylases , 2004, Nature Reviews Molecular Cell Biology.