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An analysis of the relationship between severe iron deficiency anemia and thrombocytopenia. Ann Hematol 2014; 94:535-7. [DOI: 10.1007/s00277-014-2199-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/26/2014] [Indexed: 11/25/2022]
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Mele J, Muralimanoharan S, Maloyan A, Myatt L. Impaired mitochondrial function in human placenta with increased maternal adiposity. Am J Physiol Endocrinol Metab 2014; 307:E419-25. [PMID: 25028397 PMCID: PMC4154072 DOI: 10.1152/ajpendo.00025.2014] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 07/11/2014] [Indexed: 01/09/2023]
Abstract
The placenta plays a key role in regulation of fetal growth and development and in mediating in utero developmental programming. Obesity, which is associated with chronic inflammation and mitochondrial dysfunction in many tissues, exerts a programming effect in pregnancy. We determined the effect of increasing maternal adiposity and of fetal sex on placental ATP generation, mitochondrial biogenesis, expression of electron transport chain subunits, and mitochondrial function in isolated trophoblasts. Placental tissue was collected from women with prepregnancy BMI ranging from 18.5 to 45 following C-section at term with no labor. Increasing maternal adiposity was associated with excessive production of reactive oxygen species and a significant reduction in placental ATP levels in placentae with male and female fetuses. To explore the potential mechanism of placental mitochondrial dysfunction, levels of transcription factors regulating the expression of genes involved in electron transport and mitochondrial biogenesis were measured. Our in vitro studies showed significant reduction in mitochondrial respiration in cultured primary trophoblasts with increasing maternal obesity along with an abnormal metabolic flexibility of these cells. This reduction in placental mitochondrial respiration in pregnancies complicated by maternal obesity could compromise placental function and potentially underlie the increased susceptibility of these pregnancies to fetal demise in late gestation and to developmental programming.
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Affiliation(s)
- James Mele
- Center for Pregnancy and Newborn Research, Department of Ob/Gyn, University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - Sribalasubashini Muralimanoharan
- Center for Pregnancy and Newborn Research, Department of Ob/Gyn, University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - Alina Maloyan
- Center for Pregnancy and Newborn Research, Department of Ob/Gyn, University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - Leslie Myatt
- Center for Pregnancy and Newborn Research, Department of Ob/Gyn, University of Texas Health Science Center San Antonio, San Antonio, Texas
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Tang M, Liu BJ, Wang SQ, Xu Y, Han P, Li PC, Wang ZJ, Song NH, Zhang W, Yin CJ. The role of mitochondrial aconitate (ACO2) in human sperm motility. Syst Biol Reprod Med 2014; 60:251-6. [DOI: 10.3109/19396368.2014.915360] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Richardson CL, Delehanty LL, Bullock GC, Rival CM, Tung KS, Kimpel DL, Gardenghi S, Rivella S, Goldfarb AN. Isocitrate ameliorates anemia by suppressing the erythroid iron restriction response. J Clin Invest 2013; 123:3614-23. [PMID: 23863711 DOI: 10.1172/jci68487] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/09/2013] [Indexed: 12/22/2022] Open
Abstract
The unique sensitivity of early red cell progenitors to iron deprivation, known as the erythroid iron restriction response, serves as a basis for human anemias globally. This response impairs erythropoietin-driven erythropoiesis and underlies erythropoietic repression in iron deficiency anemia. Mechanistically, the erythroid iron restriction response results from inactivation of aconitase enzymes and can be suppressed by providing the aconitase product isocitrate. Recent studies have implicated the erythroid iron restriction response in anemia of chronic disease and inflammation (ACDI), offering new therapeutic avenues for a major clinical problem; however, inflammatory signals may also directly repress erythropoiesis in ACDI. Here, we show that suppression of the erythroid iron restriction response by isocitrate administration corrected anemia and erythropoietic defects in rats with ACDI. In vitro studies demonstrated that erythroid repression by inflammatory signaling is potently modulated by the erythroid iron restriction response in a kinase-dependent pathway involving induction of the erythroid-inhibitory transcription factor PU.1. These results reveal the integration of iron and inflammatory inputs in a therapeutically tractable erythropoietic regulatory circuit.
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Affiliation(s)
- Chanté L Richardson
- Department of Pathology, University of Virginia, School of Medicine, Charlottesville, Virginia, USA
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Ganz T, Nemeth E. Iron metabolism: interactions with normal and disordered erythropoiesis. Cold Spring Harb Perspect Med 2013; 2:a011668. [PMID: 22553501 DOI: 10.1101/cshperspect.a011668] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hemoglobinopathies and other disorders of erythroid cells are often associated with abnormal iron homeostasis. We review the molecular physiology of intracellular and systemic iron regulation, and the interactions between erythropoiesis and iron homeostasis. Finally, we discuss iron disorders that affect erythropoiesis as well as erythroid disorders that cause iron dysregulation.
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Affiliation(s)
- Tomas Ganz
- Department of Medicine and Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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Anderson SA, Nizzi CP, Chang YI, Deck KM, Schmidt PJ, Galy B, Damnernsawad A, Broman AT, Kendziorski C, Hentze MW, Fleming MD, Zhang J, Eisenstein RS. The IRP1-HIF-2α axis coordinates iron and oxygen sensing with erythropoiesis and iron absorption. Cell Metab 2013; 17:282-90. [PMID: 23395174 PMCID: PMC3612289 DOI: 10.1016/j.cmet.2013.01.007] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/19/2012] [Accepted: 01/14/2013] [Indexed: 11/21/2022]
Abstract
Red blood cell production is a finely tuned process that requires coordinated oxygen- and iron-dependent regulation of cell differentiation and iron metabolism. Here, we show that translational regulation of hypoxia-inducible factor 2α (HIF-2α) synthesis by iron regulatory protein 1 (IRP1) is critical for controlling erythrocyte number. IRP1-null (Irp1(-/-)) mice display a marked transient polycythemia. HIF-2α messenger RNA (mRNA) is derepressed in kidneys of Irp1(-/-) mice but not in kidneys of Irp2(-/-) mice, leading to increased renal erythropoietin (Epo) mRNA and inappropriately elevated serum Epo levels. Expression of the iron transport genes DCytb, Dmt1, and ferroportin, as well as other HIF-2α targets, is enhanced in Irp1(-/-) duodenum. Analysis of mRNA translation state in the liver revealed IRP1-dependent dysregulation of HIF-2α mRNA translation, whereas IRP2 deficiency derepressed translation of all other known 5' iron response element (IRE)-containing mRNAs expressed in the liver. These results uncover separable physiological roles of each IRP and identify IRP1 as a therapeutic target for manipulating HIF-2α action in hematologic, oncologic, and other disorders.
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Affiliation(s)
- Sheila A. Anderson
- Dept. of Nutritional Sciences, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Christopher P. Nizzi
- Dept. of Nutritional Sciences, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Yuan-I Chang
- McCardle Laboratory for Cancer Research, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kathryn M. Deck
- Dept. of Nutritional Sciences, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Paul J. Schmidt
- Dept. of Pathology, Boston Children’s Hospital and Harvard Medical School, 320 Longwood Ave., Boston, MA 02115, USA
| | - Bruno Galy
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Alisa Damnernsawad
- McCardle Laboratory for Cancer Research, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Aimee T. Broman
- Biostatistics and Medical Informatics, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Christina Kendziorski
- Biostatistics and Medical Informatics, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
| | - Matthias W. Hentze
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Mark D. Fleming
- Dept. of Pathology, Boston Children’s Hospital and Harvard Medical School, 320 Longwood Ave., Boston, MA 02115, USA
| | - Jing Zhang
- McCardle Laboratory for Cancer Research, Univ. of Wisconsin-Madison, Madison, WI 53706, USA
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Protein kinase D-HDAC5 signaling regulates erythropoiesis and contributes to erythropoietin cross-talk with GATA1. Blood 2012; 120:4219-28. [PMID: 22983445 DOI: 10.1182/blood-2011-10-387050] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In red cell development, the differentiation program directed by the transcriptional regulator GATA1 requires signaling by the cytokine erythropoietin, but the mechanistic basis for this signaling requirement has remained unknown. Here we show that erythropoietin regulates GATA1 through protein kinase D activation, promoting histone deacetylase 5 (HDAC5) dissociation from GATA1, and subsequent GATA1 acetylation. Mice deficient for HDAC5 show resistance to anemic challenge and altered marrow responsiveness to erythropoietin injections. In ex vivo studies, HDAC5(-/-) progenitors display enhanced entry into and passage through the erythroid lineage, as well as evidence of erythropoietin-independent differentiation. These results reveal a molecular pathway that contributes to cytokine regulation of hematopoietic differentiation and offer a potential mechanism for fine tuning of lineage-restricted transcription factors by lineage-specific cytokines.
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Thomas X. DNA methyltransferase inhibitors in acute myeloid leukemia: discovery, design and first therapeutic experiences. Expert Opin Drug Discov 2012; 7:1039-51. [PMID: 22950862 DOI: 10.1517/17460441.2012.722618] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION DNA methylation is an epigenetic change mediated by DNA methyltranferases (DNMTs), which are promising epigenetic targets for the treatment of acute myeloid leukemia (AML). This is evidenced by the two DNMT inhibitors (azacitidine and decitabine) approved by the Food and Drug Administration of the United States for the treatment of high-risk myelodysplastic syndromes and the first clinical data available in AML. AREAS COVERED This paper reviews data from the international literature regarding the design, sites of impact and pharmacodynamic characteristics of DNMT inhibitors, and their first clinical experiences in AML. EXPERT OPINION The strongest advances in epigenetic therapy have been in the treatment of AML. There are now an increasing number of DNMT inhibitors. These agents may be potentially administered at different times of leukemia therapy: before or instead of chemotherapy, as maintenance therapy, prior to allogeneic stem cell transplant (SCT) or after relapse following SCT.
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Affiliation(s)
- Xavier Thomas
- Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Service d'Hématologie Clinique, Pierre Bénite, France.
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Mercadal L, Metzger M, Casadevall N, Haymann JP, Karras A, Boffa JJ, Flamant M, Vrtovsnik F, Stengel B, Froissart M. Timing and determinants of erythropoietin deficiency in chronic kidney disease. Clin J Am Soc Nephrol 2011; 7:35-42. [PMID: 22096037 DOI: 10.2215/cjn.04690511] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Anemia in patients with CKD is highly related to impaired erythropoietin (EPO) response, the timing and determinants of which remain unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study measured EPO levels and studied their relation to GFR measured by 51Cr-EDTA renal clearance (mGFR) in 336 all-stage CKD patients not receiving any erythropoiesis-stimulating agent. RESULTS In patients with anemia defined by World Health Organization criteria (hemoglobin [Hb] <13 g/dl in men and 12 g/dl in women), EPO response to Hb level varied by mGFR level. EPO and Hb levels were negatively correlated (r=-0.22, P=0.04) when mGFR was >30 ml/min per 1.73 m(2), whereas they were not correlated when mGFR was <30 (r=0.09, P=0.3; P for interaction=0.01). In patients with anemia, the ratio of observed EPO to the level predicted by the equation for their Hb level decreased from 0.72 (interquartile range, 0.57-0.95) for mGFR ≥60 ml/min per 1.73 m(2) to 0.36 (interquartile range, 0.16-0.69) for mGFR <15. Obesity, diabetes with nephropathy other than diabetic glomerulopathy, absolute iron deficiency, and high C-reactive protein concentrations were associated with increased EPO levels, independent of Hb and mGFR. CONCLUSIONS Anemia in CKD is marked by an early relative EPO deficiency, but several factors besides Hb may persistently stimulate EPO synthesis. Although EPO deficiency is likely the main determinant of anemia in patients with advanced CKD, the presence of anemia in those with mGFR >30 ml/min per 1.73 m(2) calls for other explanatory factors.
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Affiliation(s)
- Lucile Mercadal
- INSERM, CESP Centrefor Research inEpidemiology and Population Health, U1018, Epidemiology of Diabetes, Obesity, and Kidney DiseasesTeam, Villejuif, France.
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Talbot AL, Bullock GC, Delehanty LL, Sattler M, Zhao ZJ, Goldfarb AN. Aconitase regulation of erythropoiesis correlates with a novel licensing function in erythropoietin-induced ERK signaling. PLoS One 2011; 6:e23850. [PMID: 21887333 PMCID: PMC3161794 DOI: 10.1371/journal.pone.0023850] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 07/26/2011] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Erythroid development requires the action of erythropoietin (EPO) on committed progenitors to match red cell output to demand. In this process, iron acts as a critical cofactor, with iron deficiency blunting EPO-responsiveness of erythroid progenitors. Aconitase enzymes have recently been identified as possible signal integration elements that couple erythropoiesis with iron availability. In the current study, a regulatory role for aconitase during erythropoiesis was ascertained using a direct inhibitory strategy. METHODOLOGY/PRINCIPAL FINDINGS In C57BL/6 mice, infusion of an aconitase active-site inhibitor caused a hypoplastic anemia and suppressed responsiveness to hemolytic challenge. In a murine model of polycythemia vera, aconitase inhibition rapidly normalized red cell counts, but did not perturb other lineages. In primary erythroid progenitor cultures, aconitase inhibition impaired proliferation and maturation but had no effect on viability or ATP levels. This inhibition correlated with a blockade in EPO signal transmission specifically via ERK, with preservation of JAK2-STAT5 and Akt activation. Correspondingly, a physical interaction between ERK and mitochondrial aconitase was identified and found to be sensitive to aconitase inhibition. CONCLUSIONS/SIGNIFICANCE Direct aconitase inhibition interferes with erythropoiesis in vivo and in vitro, confirming a lineage-selective regulatory role involving its enzymatic activity. This inhibition spares metabolic function but impedes EPO-induced ERK signaling and disturbs a newly identified ERK-aconitase physical interaction. We propose a model in which aconitase functions as a licensing factor in ERK-dependent proliferation and differentiation, thereby providing a regulatory input for iron in EPO-dependent erythropoiesis. Directly targeting aconitase may provide an alternative to phlebotomy in the treatment of polycythemia vera.
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Affiliation(s)
- Anne-Laure Talbot
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Grant C. Bullock
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Lorrie L. Delehanty
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Martin Sattler
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Zhizhuang Joe Zhao
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Adam N. Goldfarb
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
- * E-mail:
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