1
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Newcomb G, Farkas L. Endothelial cell clonality, heterogeneity and dysfunction in pulmonary arterial hypertension. Front Med (Lausanne) 2023; 10:1304766. [PMID: 38126077 PMCID: PMC10731016 DOI: 10.3389/fmed.2023.1304766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/23/2023] [Indexed: 12/23/2023] Open
Abstract
Our understanding of the pathophysiology of pulmonary arterial hypertension (PAH) has evolved over recent years, with the recognition that endothelial cell (EC) dysfunction and inflammation play an integral role in the development of this disease. ECs within the pulmonary vasculature play a unique role in maintaining vascular integrity and barrier function, regulating gas exchange, and contributing to vascular tone. Using single-cell transcriptomics, research has shown that there are multiple, unique EC subpopulations with different phenotypes. In response to injury or certain stressors such as hypoxia, there can be a dysregulated response with aberrant endothelial injury repair involving other pulmonary vascular cells and even immune cells. This aberrant signaling cascade is potentially a primary driver of pulmonary arterial remodeling in PAH. Recent studies have examined the role of EC clonal expansion, immune dysregulation, and genetic mutations in the pathogenesis of PAH. This review summarizes the existing literature on EC subpopulations and the intricate mechanisms through which ECs develop aberrant physiologic phenotypes and contribute to PAH. Our goal is to provide a framework for understanding the unique pulmonary EC biology and pathophysiology that is involved in the development of PAH.
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Affiliation(s)
- Geoffrey Newcomb
- Department of Internal Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Laszlo Farkas
- Department of Internal Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
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2
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Ohh M, Taber CC, Ferens FG, Tarade D. Hypoxia-inducible factor underlies von Hippel-Lindau disease stigmata. eLife 2022; 11:80774. [PMID: 36040300 PMCID: PMC9427099 DOI: 10.7554/elife.80774] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/12/2022] [Indexed: 11/13/2022] Open
Abstract
von Hippel-Lindau (VHL) disease is a rare hereditary cancer syndrome that causes a predisposition to renal clear-cell carcinoma, hemangioblastoma, pheochromocytoma, and autosomal-recessive familial polycythemia. pVHL is the substrate conferring subunit of an E3 ubiquitin ligase complex that binds to the three hypoxia-inducible factor alpha subunits (HIF1-3α) for polyubiquitylation under conditions of normoxia, targeting them for immediate degradation by the proteasome. Certain mutations in pVHL have been determined to be causative of VHL disease through the disruption of HIFα degradation. However, it remains a focus of investigation and debate whether the disruption of HIFα degradation alone is sufficient to explain the complex genotype-phenotype relationship of VHL disease or whether the other lesser or yet characterized substrates and functions of pVHL impact the development of the VHL disease stigmata; the elucidation of which would have a significant ramification to the direction of research efforts and future management and care of VHL patients and for those manifesting sporadic counterparts of VHL disease. Here, we examine the current literature including the other emergent pseudohypoxic diseases and propose that the VHL disease-phenotypic spectrum could be explained solely by the varied disruption of HIFα signaling upon the loss or mutation in pVHL.
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Affiliation(s)
- Michael Ohh
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Cassandra C Taber
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Fraser G Ferens
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Daniel Tarade
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada
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3
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Li S, Li W, Yuan J, Bullova P, Wu J, Zhang X, Liu Y, Plescher M, Rodriguez J, Bedoya-Reina OC, Jannig PR, Valente-Silva P, Yu M, Henriksson MA, Zubarev RA, Smed-Sörensen A, Suzuki CK, Ruas JL, Holmberg J, Larsson C, Christofer Juhlin C, von Kriegsheim A, Cao Y, Schlisio S. Impaired oxygen-sensitive regulation of mitochondrial biogenesis within the von Hippel-Lindau syndrome. Nat Metab 2022; 4:739-758. [PMID: 35760869 PMCID: PMC9236906 DOI: 10.1038/s42255-022-00593-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/20/2022] [Indexed: 11/20/2022]
Abstract
Mitochondria are the main consumers of oxygen within the cell. How mitochondria sense oxygen levels remains unknown. Here we show an oxygen-sensitive regulation of TFAM, an activator of mitochondrial transcription and replication, whose alteration is linked to tumours arising in the von Hippel-Lindau syndrome. TFAM is hydroxylated by EGLN3 and subsequently bound by the von Hippel-Lindau tumour-suppressor protein, which stabilizes TFAM by preventing mitochondrial proteolysis. Cells lacking wild-type VHL or in which EGLN3 is inactivated have reduced mitochondrial mass. Tumorigenic VHL variants leading to different clinical manifestations fail to bind hydroxylated TFAM. In contrast, cells harbouring the Chuvash polycythaemia VHLR200W mutation, involved in hypoxia-sensing disorders without tumour development, are capable of binding hydroxylated TFAM. Accordingly, VHL-related tumours, such as pheochromocytoma and renal cell carcinoma cells, display low mitochondrial content, suggesting that impaired mitochondrial biogenesis is linked to VHL tumorigenesis. Finally, inhibiting proteolysis by targeting LONP1 increases mitochondrial content in VHL-deficient cells and sensitizes therapy-resistant tumours to sorafenib treatment. Our results offer pharmacological avenues to sensitize therapy-resistant VHL tumours by focusing on the mitochondria.
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Affiliation(s)
- Shuijie Li
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
- College of Pharmacy, Harbin Medical University, Harbin, China.
| | - Wenyu Li
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Juan Yuan
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Petra Bullova
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Jieyu Wu
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Xuepei Zhang
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Yong Liu
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Monika Plescher
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Javier Rodriguez
- Edinburgh Cancer Research Centre, IGMM, University of Edinburgh, Edinburgh, UK
| | - Oscar C Bedoya-Reina
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Paulo R Jannig
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Paula Valente-Silva
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Meng Yu
- Department of Medicine, Karolinska University Hospital, Stockholm, Sweden
| | | | - Roman A Zubarev
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Anna Smed-Sörensen
- Department of Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Carolyn K Suzuki
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers University-New Jersey Medical School, Newark, NJ, USA
| | - Jorge L Ruas
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Johan Holmberg
- Department of Molecular Biology, Faculty of Medicine, Umeå University, Umeå, Sweden
| | - Catharina Larsson
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - C Christofer Juhlin
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Alex von Kriegsheim
- Edinburgh Cancer Research Centre, IGMM, University of Edinburgh, Edinburgh, UK
| | - Yihai Cao
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Susanne Schlisio
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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4
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Wu D, Dasgupta A, Read AD, Bentley RET, Motamed M, Chen KH, Al-Qazazi R, Mewburn JD, Dunham-Snary KJ, Alizadeh E, Tian L, Archer SL. Oxygen sensing, mitochondrial biology and experimental therapeutics for pulmonary hypertension and cancer. Free Radic Biol Med 2021; 170:150-178. [PMID: 33450375 PMCID: PMC8217091 DOI: 10.1016/j.freeradbiomed.2020.12.452] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/24/2020] [Accepted: 12/30/2020] [Indexed: 02/06/2023]
Abstract
The homeostatic oxygen sensing system (HOSS) optimizes systemic oxygen delivery. Specialized tissues utilize a conserved mitochondrial sensor, often involving NDUFS2 in complex I of the mitochondrial electron transport chain, as a site of pO2-responsive production of reactive oxygen species (ROS). These ROS are converted to a diffusible signaling molecule, hydrogen peroxide (H2O2), by superoxide dismutase (SOD2). H2O2 exits the mitochondria and regulates ion channels and enzymes, altering plasma membrane potential, intracellular Ca2+ and Ca2+-sensitization and controlling acute, adaptive, responses to hypoxia that involve changes in ventilation, vascular tone and neurotransmitter release. Subversion of this O2-sensing pathway creates a pseudohypoxic state that promotes disease progression in pulmonary arterial hypertension (PAH) and cancer. Pseudohypoxia is a state in which biochemical changes, normally associated with hypoxia, occur despite normal pO2. Epigenetic silencing of SOD2 by DNA methylation alters H2O2 production, activating hypoxia-inducible factor 1α, thereby disrupting mitochondrial metabolism and dynamics, accelerating cell proliferation and inhibiting apoptosis. Other epigenetic mechanisms, including dysregulation of microRNAs (miR), increase pyruvate dehydrogenase kinase and pyruvate kinase muscle isoform 2 expression in both diseases, favoring uncoupled aerobic glycolysis. This Warburg metabolic shift also accelerates cell proliferation and impairs apoptosis. Disordered mitochondrial dynamics, usually increased mitotic fission and impaired fusion, promotes disease progression in PAH and cancer. Epigenetic upregulation of dynamin-related protein 1 (Drp1) and its binding partners, MiD49 and MiD51, contributes to the pathogenesis of PAH and cancer. Finally, dysregulation of intramitochondrial Ca2+, resulting from impaired mitochondrial calcium uniporter complex (MCUC) function, links abnormal mitochondrial metabolism and dynamics. MiR-mediated decreases in MCUC function reduce intramitochondrial Ca2+, promoting Warburg metabolism, whilst increasing cytosolic Ca2+, promoting fission. Epigenetically disordered mitochondrial O2-sensing, metabolism, dynamics, and Ca2+ homeostasis offer new therapeutic targets for PAH and cancer. Promoting glucose oxidation, restoring the fission/fusion balance, and restoring mitochondrial calcium regulation are promising experimental therapeutic strategies.
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Affiliation(s)
- Danchen Wu
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Asish Dasgupta
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Austin D Read
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Rachel E T Bentley
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Mehras Motamed
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Kuang-Hueih Chen
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Ruaa Al-Qazazi
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Jeffrey D Mewburn
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada
| | - Kimberly J Dunham-Snary
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Elahe Alizadeh
- Queen's Cardiopulmonary Unit (QCPU), Department of Medicine, Queen's University, 116 Barrie Street, Kingston, ON, K7L 3J9, Canada
| | - Lian Tian
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, UK
| | - Stephen L Archer
- Department of Medicine, Queen's University, 94 Stuart St., Kingston, Ontario, K7L 3N6, Canada.
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5
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Ghosh MC, Zhang DL, Ollivierre WH, Noguchi A, Springer DA, Linehan WM, Rouault TA. Therapeutic inhibition of HIF-2α reverses polycythemia and pulmonary hypertension in murine models of human diseases. Blood 2021; 137:2509-2519. [PMID: 33512384 PMCID: PMC8109019 DOI: 10.1182/blood.2020009138] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/04/2020] [Indexed: 12/20/2022] Open
Abstract
Polycythemia and pulmonary hypertension are 2 human diseases for which better therapies are needed. Upregulation of hypoxia-inducible factor-2α (HIF-2α) and its target genes, erythropoietin (EPO) and endothelin-1, causes polycythemia and pulmonary hypertension in patients with Chuvash polycythemia who are homozygous for the R200W mutation in the von Hippel Lindau (VHL) gene and in a murine mouse model of Chuvash polycythemia that bears the same homozygous VhlR200W mutation. Moreover, the aged VhlR200W mice developed pulmonary fibrosis, most likely due to the increased expression of Cxcl-12, another Hif-2α target. Patients with mutations in iron regulatory protein 1 (IRP1) also develop polycythemia, and Irp1-knockout (Irp1-KO) mice exhibit polycythemia, pulmonary hypertension, and cardiac fibrosis attributable to translational derepression of Hif-2α, and the resultant high expression of the Hif-2α targets EPO, endothelin-1, and Cxcl-12. In this study, we inactivated Hif-2α with the second-generation allosteric HIF-2α inhibitor MK-6482 in VhlR200W, Irp1-KO, and double-mutant VhlR200W;Irp1-KO mice. MK-6482 treatment decreased EPO production and reversed polycythemia in all 3 mouse models. Drug treatment also decreased right ventricular pressure and mitigated pulmonary hypertension in VhlR200W, Irp1-KO, and VhlR200W;Irp1-KO mice to near normal wild-type levels and normalized the movement of the cardiac interventricular septum in VhlR200Wmice. MK-6482 treatment reduced the increased expression of Cxcl-12, which, in association with CXCR4, mediates fibrocyte influx into the lungs, potentially causing pulmonary fibrosis. Our results suggest that oral intake of MK-6482 could represent a new approach to treatment of patients with polycythemia, pulmonary hypertension, pulmonary fibrosis, and complications caused by elevated expression of HIF-2α.
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Affiliation(s)
- Manik C Ghosh
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - De-Liang Zhang
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Wade H Ollivierre
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Audrey Noguchi
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, and
| | | | - W Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Tracey A Rouault
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
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6
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Jonasch E, Walker CL, Rathmell WK. Clear cell renal cell carcinoma ontogeny and mechanisms of lethality. Nat Rev Nephrol 2021; 17:245-261. [PMID: 33144689 PMCID: PMC8172121 DOI: 10.1038/s41581-020-00359-2] [Citation(s) in RCA: 286] [Impact Index Per Article: 95.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 02/07/2023]
Abstract
The molecular features that define clear cell renal cell carcinoma (ccRCC) initiation and progression are being increasingly defined. The TRACERx Renal studies and others that have described the interaction between tumour genomics and remodelling of the tumour microenvironment provide important new insights into the molecular drivers underlying ccRCC ontogeny and progression. Our understanding of common genomic and chromosomal copy number abnormalities in ccRCC, including chromosome 3p loss, provides a mechanistic framework with which to organize these abnormalities into those that drive tumour initiation events, those that drive tumour progression and those that confer lethality. Truncal mutations in ccRCC, including those in VHL, SET2, PBRM1 and BAP1, may engender genomic instability and promote defects in DNA repair pathways. The molecular features that arise from these defects enable categorization of ccRCC into clinically and therapeutically relevant subtypes. Consideration of the interaction of these subtypes with the tumour microenvironment reveals that specific mutations seem to modulate immune cell populations in ccRCC tumours. These findings present opportunities for disease prevention, early detection, prognostication and treatment.
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Affiliation(s)
- Eric Jonasch
- Department of Genitourinary Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Cheryl Lyn Walker
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
| | - W Kimryn Rathmell
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
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7
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Jain IH, Zazzeron L, Goldberger O, Marutani E, Wojtkiewicz GR, Ast T, Wang H, Schleifer G, Stepanova A, Brepoels K, Schoonjans L, Carmeliet P, Galkin A, Ichinose F, Zapol WM, Mootha VK. Leigh Syndrome Mouse Model Can Be Rescued by Interventions that Normalize Brain Hyperoxia, but Not HIF Activation. Cell Metab 2019; 30:824-832.e3. [PMID: 31402314 PMCID: PMC6903907 DOI: 10.1016/j.cmet.2019.07.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/29/2019] [Accepted: 07/16/2019] [Indexed: 02/07/2023]
Abstract
Leigh syndrome is a devastating mitochondrial disease for which there are no proven therapies. We previously showed that breathing chronic, continuous hypoxia can prevent and even reverse neurological disease in the Ndufs4 knockout (KO) mouse model of complex I (CI) deficiency and Leigh syndrome. Here, we show that genetic activation of the hypoxia-inducible factor transcriptional program via any of four different strategies is insufficient to rescue disease. Rather, we observe an age-dependent decline in whole-body oxygen consumption. These mice exhibit brain tissue hyperoxia, which is normalized by hypoxic breathing. Alternative experimental strategies to reduce oxygen delivery, including breathing carbon monoxide (600 ppm in air) or severe anemia, can reverse neurological disease. Therefore, unused oxygen is the most likely culprit in the pathology of this disease. While pharmacologic activation of the hypoxia response is unlikely to alleviate disease in vivo, interventions that safely normalize brain tissue hyperoxia may hold therapeutic potential.
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Affiliation(s)
- Isha H Jain
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA; Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Luca Zazzeron
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Olga Goldberger
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA; Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Eizo Marutani
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Gregory R Wojtkiewicz
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Tslil Ast
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA; Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Hong Wang
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA; Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Grigorij Schleifer
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Anna Stepanova
- Department of Pediatrics, Division of Neonatology, Columbia University, New York, NY, USA
| | - Kathleen Brepoels
- Laboratory of Angiogenesis and Vascular Metabolism, VIB-KU Leuven, Center for Cancer Biology, Leuven, Belgium; Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology and Leuven Cancer Institute (LKI), KU Leuven, Leuven, Belgium
| | - Luc Schoonjans
- Laboratory of Angiogenesis and Vascular Metabolism, VIB-KU Leuven, Center for Cancer Biology, Leuven, Belgium; Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology and Leuven Cancer Institute (LKI), KU Leuven, Leuven, Belgium
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, VIB-KU Leuven, Center for Cancer Biology, Leuven, Belgium; Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology and Leuven Cancer Institute (LKI), KU Leuven, Leuven, Belgium
| | - Alexander Galkin
- Department of Pediatrics, Division of Neonatology, Columbia University, New York, NY, USA
| | - Fumito Ichinose
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Warren M Zapol
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA.
| | - Vamsi K Mootha
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA; Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA.
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8
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Gordeuk VR, Key NS, Prchal JT. Re-evaluation of hematocrit as a determinant of thrombotic risk in erythrocytosis. Haematologica 2019; 104:653-658. [PMID: 30872370 PMCID: PMC6442963 DOI: 10.3324/haematol.2018.210732] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/28/2019] [Indexed: 12/20/2022] Open
Abstract
Here we critically evaluate the role of elevated hematocrit as the principal determinant of thrombotic risk in polycythemia and erythrocytosis, defined by an expansion of red cell mass. Since red cell volume determination is no longer readily available, in clinical practice, polycythemia and erythrocytosis are defined by elevated hemoglobin and hematocrit. Thrombosis is common in Chuvash erythrocytosis and polycythemia vera. Although the increased thrombotic risk is assumed to be due to the elevated hematocrit and an associated increase in blood viscosity, thrombosis does not accompany most types of erythrocytosis. We review studies indicating that the occurrence of thrombosis in Chuvash erythrocytosis is independent of hematocrit, that the thrombotic risk is paradoxically increased by phlebotomy in Chuvash erythrocytosis, and that, when compared to chemotherapy, phlebotomy is associated with increased thrombotic risk in polycythemia vera. Inherited and environmental causes that lead to polycythemia and erythrocytosis are accompanied by diverse cellular changes that could directly affect thrombotic risk, irrespective of the elevated hematocrit. The pressing issue in these disorders is to define factors other than elevated hematocrit that determine thrombotic risk. Defining these predisposing factors in polycythemia and erythrocytosis should then lead to rational therapies and facilitate development of targeted interventions.
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Affiliation(s)
- Victor R Gordeuk
- Division of Hematology and Oncology, University of Illinois at Chicago, IL
| | - Nigel S Key
- Division of Hematology-Oncology and UNC Hemophilia and Thrombosis Center, UNC, Chapel Hill, NC
| | - Josef T Prchal
- Division of Hematology and Hematologic Malignancies, University of Utah and Huntsman Cancer Center, Salt Lake City, UT, USA
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9
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Chappell JC, Payne LB, Rathmell WK. Hypoxia, angiogenesis, and metabolism in the hereditary kidney cancers. J Clin Invest 2019; 129:442-451. [PMID: 30614813 DOI: 10.1172/jci120855] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The field of hereditary kidney cancer has begun to mature following the identification of several germline syndromes that define genetic and molecular features of this cancer. Molecular defects within these hereditary syndromes demonstrate consistent deficits in angiogenesis and metabolic signaling, largely driven by altered hypoxia signaling. The classical mutation, loss of function of the von Hippel-Lindau (VHL) tumor suppressor, provides a human pathogenesis model for critical aspects of pseudohypoxia. These features are mimicked in a less common hereditary renal tumor syndrome, known as hereditary leiomyomatosis and renal cell carcinoma. Here, we review renal tumor angiogenesis and metabolism from a HIF-centric perspective, considering alterations in the hypoxic landscape, and molecular deviations resulting from high levels of HIF family members. Mutations underlying HIF deregulation drive multifactorial aberrations in angiogenic signals and metabolism. The mechanisms by which these defects drive tumor growth are still emerging. However, the distinctive patterns of angiogenesis and glycolysis-/glutamine-dependent bioenergetics provide insight into the cellular environment of these cancers. The result is a scenario permissive for aggressive tumorigenesis especially within the proximal renal tubule. These features of tumorigenesis have been highly actionable in kidney cancer treatments, and will likely continue as central tenets of kidney cancer therapeutics.
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Affiliation(s)
- John C Chappell
- Center for Heart and Regenerative Medicine, Departments of Biomedical Sciences and Biomedical Engineering and Mechanics, Virginia Tech Carilion Research Institute, Roanoke, Virginia, USA
| | - Laura Beth Payne
- Center for Heart and Regenerative Medicine, Departments of Biomedical Sciences and Biomedical Engineering and Mechanics, Virginia Tech Carilion Research Institute, Roanoke, Virginia, USA
| | - W Kimryn Rathmell
- Vanderbilt-Ingram Cancer Center, Departments of Medicine and Biochemistry, Division of Hematology and Oncology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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10
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Briston T, Stephen JM, Thomas LW, Esposito C, Chung YL, Syafruddin SE, Turmaine M, Maddalena LA, Greef B, Szabadkai G, Maxwell PH, Vanharanta S, Ashcroft M. VHL-Mediated Regulation of CHCHD4 and Mitochondrial Function. Front Oncol 2018; 8:388. [PMID: 30338240 PMCID: PMC6180203 DOI: 10.3389/fonc.2018.00388] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/29/2018] [Indexed: 12/30/2022] Open
Abstract
Dysregulated mitochondrial function is associated with the pathology of a wide range of diseases including renal disease and cancer. Thus, investigating regulators of mitochondrial function is of particular interest. Previous work has shown that the von Hippel-Lindau tumor suppressor protein (pVHL) regulates mitochondrial biogenesis and respiratory chain function. pVHL is best known as an E3-ubiquitin ligase for the α-subunit of the hypoxia inducible factor (HIF) family of dimeric transcription factors. In normoxia, pVHL recognizes and binds hydroxylated HIF-α (HIF-1α and HIF-2α), targeting it for ubiquitination and proteasomal degradation. In this way, HIF transcriptional activity is tightly controlled at the level of HIF-α protein stability. At least 80% of clear cell renal carcinomas exhibit inactivation of the VHL gene, which leads to HIF-α protein stabilization and constitutive HIF activation. Constitutive HIF activation in renal carcinoma drives tumor progression and metastasis. Reconstitution of wild-type VHL protein (pVHL) in pVHL-defective renal carcinoma cells not only suppresses HIF activation and tumor growth, but also enhances mitochondrial respiratory chain function via mechanisms that are not fully elucidated. Here, we show that pVHL regulates mitochondrial function when re-expressed in pVHL-defective 786O and RCC10 renal carcinoma cells distinct from its regulation of HIF-α. Expression of CHCHD4, a key component of the disulphide relay system (DRS) involved in mitochondrial protein import within the intermembrane space (IMS) was elevated by pVHL re-expression alongside enhanced expression of respiratory chain subunits of complex I (NDUFB10) and complex IV (mtCO-2 and COX IV). These changes correlated with increased oxygen consumption rate (OCR) and dynamic changes in glucose and glutamine metabolism. Knockdown of HIF-2α also led to increased OCR, and elevated expression of CHCHD4, NDUFB10, and COXIV in 786O cells. Expression of pVHL mutant proteins (R200W, N78S, D126N, and S183L) that constitutively stabilize HIF-α but differentially promote glycolytic metabolism, were also found to differentially promote the pVHL-mediated mitochondrial phenotype. Parallel changes in mitochondrial morphology and the mitochondrial network were observed. Our study reveals a new role for pVHL in regulating CHCHD4 and mitochondrial function in renal carcinoma cells.
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Affiliation(s)
- Thomas Briston
- Division of Medicine, Centre for Cell Signalling and Molecular Genetics, University College London, London, United Kingdom
| | - Jenna M. Stephen
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Luke W. Thomas
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Cinzia Esposito
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Yuen-Li Chung
- Cancer Research UK Cancer Imaging Centre, Institute of Cancer Research London, London, United Kingdom
| | - Saiful E. Syafruddin
- Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - Mark Turmaine
- Division of Biosciences, Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Lucas A. Maddalena
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Basma Greef
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Gyorgy Szabadkai
- Division of Biosciences, Department of Cell and Developmental Biology, University College London, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Patrick H. Maxwell
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Sakari Vanharanta
- Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - Margaret Ashcroft
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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11
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Adamson KI, Sheridan E, Grierson AJ. Use of zebrafish models to investigate rare human disease. J Med Genet 2018; 55:641-649. [PMID: 30065072 DOI: 10.1136/jmedgenet-2018-105358] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 01/07/2023]
Abstract
Rare diseases are collectively common and often extremely debilitating. Following the emergence of next-generation sequencing (NGS) technologies, the variants underpinning rare genetic disorders are being unearthed at an accelerating rate. However, many rare conditions lack effective treatments due to their poorly understood pathophysiology. There is therefore a growing demand for the development of novel experimental models of rare genetic diseases, so that potentially causative variants can be validated, pathogenic mechanisms can be investigated and therapeutic targets can be identified. Animal models of rare diseases need to be genetically and physiologically similar to humans, and well-suited to large-scale experimental manipulation, considering the vast number of novel variants that are being identified through NGS. The zebrafish has emerged as a popular model system for investigating these variants, combining conserved vertebrate characteristics with a capacity for large-scale phenotypic and therapeutic screening. In this review, we aim to highlight the unique advantages of the zebrafish over other in vivo model systems for the large-scale study of rare genetic variants. We will also consider the generation of zebrafish disease models from a practical standpoint, by discussing how genome editing technologies, particularly the recently developed clustered regularly interspaced repeat (CRISPR)/CRISPR-associated protein 9 system, can be used to model rare pathogenic variants in zebrafish. Finally, we will review examples in the literature where zebrafish models have played a pivotal role in confirming variant causality and revealing the underlying mechanisms of rare diseases, often with wider implications for our understanding of human biology.
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Affiliation(s)
- Kathryn Isabel Adamson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | | | - Andrew James Grierson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK.,Department of Neuroscience, University of Sheffield, Sheffield, UK
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12
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Ghosh MC, Zhang DL, Ollivierre H, Eckhaus MA, Rouault TA. Translational repression of HIF2α expression in mice with Chuvash polycythemia reverses polycythemia. J Clin Invest 2018; 128:1317-1325. [PMID: 29480820 DOI: 10.1172/jci97684] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/09/2018] [Indexed: 01/28/2023] Open
Abstract
Chuvash polycythemia is an inherited disease caused by a homozygous germline VHLR200W mutation, which leads to impaired degradation of HIF2α, elevated levels of serum erythropoietin, and erythrocytosis/polycythemia. This phenotype is recapitulated by a mouse model bearing a homozygous VhlR200W mutation. We previously showed that iron-regulatory protein 1-knockout (Irp1-knockout) mice developed erythrocytosis/polycythemia through translational derepression of Hif2α, suggesting that IRP1 could be a therapeutic target to treat Chuvash polycythemia. Here, we fed VhlR200W mice supplemented with Tempol, a small, stable nitroxide molecule and observed that Tempol decreased erythropoietin production, corrected splenomegaly, normalized hematocrit levels, and increased the lifespans of these mice. We attribute the reversal of erythrocytosis/polycythemia to translational repression of Hif2α expression by Tempol-mediated increases in the IRE-binding activity of Irp1, as reversal of polycythemia was abrogated in VhlR200W mice in which Irp1 was genetically ablated. Thus, a new approach to the treatment of patients with Chuvash polycythemia may include dietary supplementation of Tempol, which decreased Hif2α expression and markedly reduced life-threatening erythrocytosis/polycythemia in the VhlR200W mice.
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Affiliation(s)
- Manik C Ghosh
- Metals Biology and Molecular Medicine Group, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and
| | - De-Liang Zhang
- Metals Biology and Molecular Medicine Group, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and
| | - Hayden Ollivierre
- Metals Biology and Molecular Medicine Group, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and
| | | | - Tracey A Rouault
- Metals Biology and Molecular Medicine Group, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and
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13
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Sala MA, Chen C, Zhang Q, Do-Umehara HC, Wu W, Misharin AV, Waypa GB, Fang D, Budinger GRS, Liu S, Chandel NS, Schumacker PT, Sznajder JI, Liu J. JNK2 up-regulates hypoxia-inducible factors and contributes to hypoxia-induced erythropoiesis and pulmonary hypertension. J Biol Chem 2017; 293:271-284. [PMID: 29118187 DOI: 10.1074/jbc.ra117.000440] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/07/2017] [Indexed: 11/06/2022] Open
Abstract
The hypoxic response is a stress response triggered by low oxygen tension. Hypoxia-inducible factors (HIFs) play a prominent role in the pathobiology of hypoxia-associated conditions, including pulmonary hypertension (PH) and polycythemia. The c-Jun N-terminal protein kinase (JNK), a stress-activated protein kinase that consists of two ubiquitously expressed isoforms, JNK1 and JNK2, and a tissue-specific isoform, JNK3, has been shown to be activated by hypoxia. However, the physiological role of JNK1 and JNK2 in the hypoxic response remains elusive. Here, using genetic knockout cells and/or mice, we show that JNK2, but not JNK1, up-regulates the expression of HIF-1α and HIF-2α and contributes to hypoxia-induced PH and polycythemia. Knockout or silencing of JNK2, but not JNK1, prevented the accumulation of HIF-1α in hypoxia-treated cells. Loss of JNK2 resulted in a decrease in HIF-1α and HIF-2α mRNA levels under resting conditions and in response to hypoxia. Consequently, hypoxia-treated Jnk2-/- mice had reduced erythropoiesis and were less prone to polycythemia because of decreased expression of the HIF target gene erythropoietin (Epo). Jnk2-/- mice were also protected from hypoxia-induced PH, as indicated by lower right ventricular systolic pressure, a process that depends on HIF. Taken together, our results suggest that JNK2 is a positive regulator of HIFs and therefore may contribute to HIF-dependent pathologies.
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Affiliation(s)
- Marc A Sala
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Cong Chen
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Qiao Zhang
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611; School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Hanh Chi Do-Umehara
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Wenjiao Wu
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611; School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Alexander V Misharin
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Gregory B Waypa
- Department of Pediatrics, Northwestern University, Chicago, Illinois 60611
| | - Deyu Fang
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - G R Scott Budinger
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Shuwen Liu
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Navdeep S Chandel
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Paul T Schumacker
- Department of Pediatrics, Northwestern University, Chicago, Illinois 60611
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611
| | - Jing Liu
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, Illinois 60611.
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14
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Song J, Sundar K, Gangaraju R, Prchal JT. Regulation of erythropoiesis after normoxic return from chronic sustained and intermittent hypoxia. J Appl Physiol (1985) 2017; 123:1671-1675. [PMID: 28522758 DOI: 10.1152/japplphysiol.00119.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hypoxia increases erythropoiesis mediated by hypoxia-inducible transcription factors (HIF), which regulate erythropoietin transcription. Neocytolysis is a physiological mechanism that corrects polycythemia from chronic sustained hypoxemia by transient, preferential destruction of young RBCs after normoxia is restored. We showed that neocytolysis is caused by excessive mitochondrial-derived reactive oxygen species in reticulocytes mediated by downregulation of HIF-controlled BNIP3L regulated mitophagy and a decrease in RBC antioxidant catalase (CAT) in hypoxia-produced erythrocytes. Decreased CAT results from hypoxia-induced miR-21 that downregulates CAT. This correlates with a transient acute decrease of HIF-1 at normoxic return that is associated with normalization of red cell mass.
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15
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Pullamsetti SS, Perros F, Chelladurai P, Yuan J, Stenmark K. Transcription factors, transcriptional coregulators, and epigenetic modulation in the control of pulmonary vascular cell phenotype: therapeutic implications for pulmonary hypertension (2015 Grover Conference series). Pulm Circ 2017; 6:448-464. [PMID: 28090287 DOI: 10.1086/688908] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Pulmonary hypertension (PH) is a complex and multifactorial disease involving genetic, epigenetic, and environmental factors. Numerous stimuli and pathological conditions facilitate severe vascular remodeling in PH by activation of a complex cascade of signaling pathways involving vascular cell proliferation, differentiation, and inflammation. Multiple signaling cascades modulate the activity of certain sequence-specific DNA-binding transcription factors (TFs) and coregulators that are critical for the transcriptional regulation of gene expression that facilitates PH-associated vascular cell phenotypes, as demonstrated by several studies summarized in this review. Past studies have largely focused on the role of the genetic component in the development of PH, while the presence of epigenetic alterations such as microRNAs, DNA methylation, histone levels, and histone deacetylases in PH is now also receiving increasing attention. Epigenetic regulation of chromatin structure is also recognized to influence gene expression in development or disease states. Therefore, a complete understanding of the mechanisms involved in altered gene expression in diseased cells is vital for the design of novel therapeutic strategies. Recent technological advances in DNA sequencing will provide a comprehensive improvement in our understanding of mechanisms involved in the development of PH. This review summarizes current concepts in TF and epigenetic control of cell phenotype in pulmonary vascular disease and discusses the current issues and possibilities in employing potential epigenetic or TF-based therapies for achieving complete reversal of PH.
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Affiliation(s)
- Soni S Pullamsetti
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, member of the German Center for Lung Research (DZL), Bad Nauheim, Germany; Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), member of the DZL, Justus-Liebig University, Giessen, Germany
| | - Frédéric Perros
- Université Paris-Sud; and Institut national de la santé et de la recherche médicale (Inserm) Unité Mixte de Recherche (UMR_S) 999, Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Prakash Chelladurai
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, member of the German Center for Lung Research (DZL), Bad Nauheim, Germany
| | - Jason Yuan
- University of Arizona, Tucson, Arizona, USA
| | - Kurt Stenmark
- Cardiovascular Pulmonary Research Laboratories, Department of Medicine and Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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16
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Maron BA, Machado RF, Shimoda L. Pulmonary vascular and ventricular dysfunction in the susceptible patient (2015 Grover Conference series). Pulm Circ 2016; 6:426-438. [PMID: 28090285 PMCID: PMC5210067 DOI: 10.1086/688315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/21/2016] [Indexed: 12/14/2022] Open
Abstract
Pulmonary blood vessel structure and tone are maintained by a complex interplay between endogenous vasoactive factors and oxygen-sensing intermediaries. Under physiological conditions, these signaling networks function as an adaptive interface between the pulmonary circulation and environmental or acquired perturbations to preserve oxygenation and maintain systemic delivery of oxygen-rich hemoglobin. Chronic exposure to hypoxia, however, triggers a range of pathogenetic mechanisms that include hypoxia-inducible factor 1α (HIF-1α)-dependent upregulation of the vasoconstrictor peptide endothelin 1 in pulmonary endothelial cells. In pulmonary arterial smooth muscle cells, chronic hypoxia induces HIF-1α-mediated upregulation of canonical transient receptor potential proteins, as well as increased Rho kinase-Ca2+ signaling and pulmonary arteriole synthesis of the profibrotic hormone aldosterone. Collectively, these mechanisms contribute to a contractile or hypertrophic pulmonary vascular phenotype. Genetically inherited disorders in hemoglobin structure are also an important etiology of abnormal pulmonary vasoreactivity. In sickle cell anemia, for example, consumption of the vasodilator and antimitogenic molecule nitric oxide by cell-free hemoglobin is an important mechanism underpinning pulmonary hypertension. Contemporary genomic and transcriptomic analytic methods have also allowed for the discovery of novel risk factors relevant to sickle cell disease, including GALNT13 gene variants. In this report, we review cutting-edge observations characterizing these and other pathobiological mechanisms that contribute to pulmonary vascular and right ventricular vulnerability.
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Affiliation(s)
- Bradley A. Maron
- Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA; and Department of Cardiology, Boston Veterans Affairs Healthcare System, Boston, Massachusetts, USA
| | - Roberto F. Machado
- Division of Pulmonary, Critical Care Medicine, Sleep and Allergy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Larissa Shimoda
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Asthma and Allergy Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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17
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Gao JL, Shui YM, Jiang W, Huang EY, Shou QY, Ji X, He BC, Lv GY, He TC. Hypoxia pathway and hypoxia-mediated extensive extramedullary hematopoiesis are involved in ursolic acid's anti-metastatic effect in 4T1 tumor bearing mice. Oncotarget 2016; 7:71802-71816. [PMID: 27708244 PMCID: PMC5342124 DOI: 10.18632/oncotarget.12375] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/24/2016] [Indexed: 01/13/2023] Open
Abstract
Hypoxic in the tumor mass is leading to the myeloproliferative-like disease (leukemoid reaction) and anemia of body, which characterized by strong extensive extramedullary hematopoiesis (EMH) in spleen. As the key transcription factor of hypoxia, hypoxia-inducible factor-1 (HIF-1) activates the expression of genes essential for EMH processes including enhanced blood cell production and angiogenesis. We found ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid, inhibited growth of breast cancer both in vivo and in vitro. The suppression was mediated through the inhibition of multiple cell pathways linked to inflammation, proliferation, angiogenesis, and metastasis. UA also suppressed the leukemoid reaction and the EMH phenomenon of the tumor bearing mice without any significant suppression on body weight (i.p. by 20 mg/kg for 28 days). This is associated with the significant decrease in white blood cells (WBC), platelets (PLT) and spleen weight. During this process, we also detected the down-regulation of cell proliferative genes (PCNA, and β-catenin), and metastatic genes (VEGF, and HIF-1α), as well as the depression of nuclear protein intensity of HIF-1α. Furthermore, the expression of E2F1, p53 and MDM2 genes were increased in UA group when the VEGF and HIF-1α was over-expressed. Cancer cells were sensitive to UA treating after the silencing of HIF-1α and the response of Hypoxic pathway reporter to UA was suppressed when HIF-1α was over expressed. Overall, our results from experimental and predictive studies suggest that the anticancer activity of UA may be at least in part caused by suppressing the cancer hypoxia and hypoxia-mediated EMH.
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Affiliation(s)
- Jian-Li Gao
- Zhejiang Chinese Medical University, Hangzhou, 310053, China
- Molecular Oncology Laboratory, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Yan-Mei Shui
- Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Wei Jiang
- Molecular Oncology Laboratory, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - En-Yi Huang
- Chongqing Medical University, Chongqing 400016, China
| | - Qi-Yang Shou
- Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Xin Ji
- School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Bai-Cheng He
- Chongqing Medical University, Chongqing 400016, China
| | - Gui-Yuan Lv
- Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Tong-Chuan He
- Molecular Oncology Laboratory, The University of Chicago Medical Center, Chicago, IL 60637, USA
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18
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The Zinc Finger of Prolyl Hydroxylase Domain Protein 2 Is Essential for Efficient Hydroxylation of Hypoxia-Inducible Factor α. Mol Cell Biol 2016; 36:2328-43. [PMID: 27325674 DOI: 10.1128/mcb.00090-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/12/2016] [Indexed: 12/21/2022] Open
Abstract
Prolyl hydroxylase domain protein 2 (PHD2) (also known as EGLN1) is a key oxygen sensor in mammals that posttranslationally modifies hypoxia-inducible factor α (HIF-α) and targets it for degradation. In addition to its catalytic domain, PHD2 contains an evolutionarily conserved zinc finger domain, which we have previously proposed recruits PHD2 to the HSP90 pathway to promote HIF-α hydroxylation. Here, we provide evidence that this recruitment is critical both in vitro and in vivo We show that in vitro, the zinc finger can function as an autonomous recruitment domain to facilitate interaction with HIF-α. In vivo, ablation of zinc finger function by a C36S/C42S Egln1 knock-in mutation results in upregulation of the erythropoietin gene, erythrocytosis, and augmented hypoxic ventilatory response, all hallmarks of Egln1 loss of function and HIF stabilization. Hence, the zinc finger ordinarily performs a critical positive regulatory function. Intriguingly, the function of this zinc finger is impaired in high-altitude-adapted Tibetans, suggesting that their adaptation to high altitude may, in part, be due to a loss-of-function EGLN1 allele. Thus, these findings have important implications for understanding both the molecular mechanism of the hypoxic response and human adaptation to high altitude.
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19
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Liang R, Ghaffari S. Advances in understanding the mechanisms of erythropoiesis in homeostasis and disease. Br J Haematol 2016; 174:661-73. [PMID: 27442953 DOI: 10.1111/bjh.14194] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Anaemia or decreased blood haemoglobin is the most common blood disorder often characterized by reduced red blood cell (RBC) numbers. RBCs are produced from differentiation and commitment of haematopoietic stem cells to the erythroid lineage by a process called erythropoiesis. Coordination of erythropoietin receptor signalling with several erythroid transcription factors including GATA1 is essential for this process. A number of additional players that are critical for RBC production have been identified in recent years. Major technological advances, such as the development of RNA interference, genetically modified animals, including zebrafish, and imaging flow cytometry have led to these discoveries; the emergence of -omics approaches in combination with the optimization of ex vivo erythroid cultures have also produced a more comprehensive understanding of erythropoiesis. Here we summarize studies describing novel regulators of erythropoiesis that modulate erythroid cell production in the context of human erythroid disorders involving hypoxia, iron regulation, immune-related molecules, and the transcription factor FOXO3.
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Affiliation(s)
- Raymond Liang
- Department of Developmental & Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Developmental and Stem Cell Biology Multidisciplinary Training Area, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Saghi Ghaffari
- Department of Developmental & Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Developmental and Stem Cell Biology Multidisciplinary Training Area, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Medicine, Division of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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20
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Slingo M, Cole M, Carr C, Curtis MK, Dodd M, Giles L, Heather LC, Tyler D, Clarke K, Robbins PA. The von Hippel-Lindau Chuvash mutation in mice alters cardiac substrate and high-energy phosphate metabolism. Am J Physiol Heart Circ Physiol 2016; 311:H759-67. [PMID: 27422990 PMCID: PMC5142182 DOI: 10.1152/ajpheart.00912.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 07/12/2016] [Indexed: 02/07/2023]
Abstract
This is the first integrative metabolic and functional study of the effects of modest hypoxia-inducible factor manipulation within the heart. Of particular note, the combination (and correlation) of perfused heart metabolic flux measurements with the new technique of real-time in vivo magnetic resonance spectroscopy using hyperpolarized pyruvate is a novel development. Hypoxia-inducible factor (HIF) appears to function as a global master regulator of cellular and systemic responses to hypoxia. HIF pathway manipulation is of therapeutic interest; however, global systemic upregulation of HIF may have as yet unknown effects on multiple processes. We used a mouse model of Chuvash polycythemia (CP), a rare genetic disorder that modestly increases expression of HIF target genes in normoxia, to understand what these effects might be within the heart. An integrated in and ex vivo approach was employed. Compared with wild-type controls, CP mice had evidence (using in vivo magnetic resonance imaging) of pulmonary hypertension, right ventricular hypertrophy, and increased left ventricular ejection fraction. Glycolytic flux (measured using [3H]glucose) in the isolated contracting perfused CP heart was 1.8-fold higher. Net lactate efflux was 1.5-fold higher. Furthermore, in vivo 13C-magnetic resonance spectroscopy (MRS) of hyperpolarized [13C1]pyruvate revealed a twofold increase in real-time flux through lactate dehydrogenase in the CP hearts and a 1.6-fold increase through pyruvate dehydrogenase. 31P-MRS of perfused CP hearts under increased workload (isoproterenol infusion) demonstrated increased depletion of phosphocreatine relative to ATP. Intriguingly, no changes in cardiac gene expression were detected. In summary, a modest systemic dysregulation of the HIF pathway resulted in clear alterations in cardiac metabolism and energetics. However, in contrast to studies generating high HIF levels within the heart, the CP mice showed neither the predicted changes in gene expression nor any degree of LV impairment. We conclude that the effects of manipulating HIF on the heart are dose dependent.
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Affiliation(s)
- Mary Slingo
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Mark Cole
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Carolyn Carr
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Mary K Curtis
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Michael Dodd
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Lucia Giles
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Lisa C Heather
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Damian Tyler
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Kieran Clarke
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
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21
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Bart NK, Curtis MK, Cheng HY, Hungerford SL, McLaren R, Petousi N, Dorrington KL, Robbins PA. Elevation of iron storage in humans attenuates the pulmonary vascular response to hypoxia. J Appl Physiol (1985) 2016; 121:537-44. [PMID: 27418684 PMCID: PMC5007321 DOI: 10.1152/japplphysiol.00032.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 07/07/2016] [Indexed: 12/23/2022] Open
Abstract
This study shows that a single dose of intravenous iron reduces the effects of hypoxia on the pulmonary circulation in a manner that persists for at least several weeks. This is long after the foreign iron-sugar complex has been cleared from the blood. It raises the possibility that manipulating iron stores, even in people who are not initially iron deficient, could be used for therapeutic gain in some forms of pulmonary hypertension. Sustained hypoxia over several hours induces a progressive rise in pulmonary artery systolic pressure (PASP). Administration of intravenous iron immediately prior to the hypoxia exposure abrogates this effect, suggesting that manipulation of iron stores may modify hypoxia-induced pulmonary hypertension. Iron (ferric carboxymaltose) administered intravenously has a plasma half-life of 7-12 h. Thus any therapeutic use of intravenous iron would require its effect on PASP to persist long after the iron-sugar complex has been cleared from the blood. To examine this, we studied PASP during sustained (6 h) hypoxia on 4 separate days (days 0, 1, 8, and 43) in 22 participants. On day 0, the rise in PASP with hypoxia was well matched between the iron and saline groups. On day 1, each participant received either 1 g of ferric carboxymaltose or saline in a double-blind manner. After administration of intravenous iron, the rise in PASP with hypoxia was attenuated by ∼50%, and this response remained suppressed on both days 8 and 43 (P < 0.001). Following administration of intravenous iron, values for ferritin concentration, transferrin saturation, and hepcidin concentration rose significantly (P < 0.001, P < 0.005, and P < 0.001, respectively), and values for transferrin concentration fell significantly (P < 0.001). These changes remained significant at day 43. We conclude that the attenuation of the pulmonary vascular response to hypoxia by elevation of iron stores persists long after the artificial iron-sugar complex has been eliminated from the blood. The persistence of this effect suggests that intravenous iron may be of benefit in some forms of pulmonary hypertension.
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Affiliation(s)
- Nicole K Bart
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - M Kate Curtis
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Hung-Yuan Cheng
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Sara L Hungerford
- Department of Medicine, Royal Berkshire NHS Foundation Trust, Reading, United Kingdom; and
| | - Ross McLaren
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nayia Petousi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom; Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Keith L Dorrington
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom;
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22
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Comparative systems pharmacology of HIF stabilization in the prevention of retinopathy of prematurity. Proc Natl Acad Sci U S A 2016; 113:E2516-25. [PMID: 27091985 DOI: 10.1073/pnas.1523005113] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Retinopathy of prematurity (ROP) causes 100,000 new cases of childhood blindness each year. ROP is initiated by oxygen supplementation necessary to prevent neonatal death. We used organ systems pharmacology to define the transcriptomes of mice that were cured of oxygen-induced retinopathy (OIR, ROP model) by hypoxia-inducible factor (HIF) stabilization via HIF prolyl hydroxylase inhibition using the isoquinolone Roxadustat or the 2-oxoglutarate analog dimethyloxalylglycine (DMOG). Although both molecules conferred a protective phenotype, gene expression analysis by RNA sequencing found that Roxadustat can prevent OIR by two pathways: direct retinal HIF stabilization and induction of aerobic glycolysis or indirect hepatic HIF-1 stabilization and increased serum angiokines. As predicted by pathway analysis, Roxadustat rescued the hepatic HIF-1 knockout mouse from retinal oxygen toxicity, whereas DMOG could not. The simplicity of systemic treatment that targets both the liver and the eye provides a rationale for protecting the severely premature infant from oxygen toxicity.
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23
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Ramakrishnan SK, Zhang H, Takahashi S, Centofanti B, Periyasamy S, Weisz K, Chen Z, Uhler MD, Rui L, Gonzalez FJ, Shah YM. HIF2α Is an Essential Molecular Brake for Postprandial Hepatic Glucagon Response Independent of Insulin Signaling. Cell Metab 2016; 23:505-16. [PMID: 26853750 PMCID: PMC4785079 DOI: 10.1016/j.cmet.2016.01.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/25/2015] [Accepted: 01/02/2016] [Indexed: 01/01/2023]
Abstract
Glucagon drives hepatic gluconeogenesis and maintains blood glucose levels during fasting. The mechanism that attenuates glucagon action following refeeding is not understood. The present study demonstrates an increase in perivenous liver hypoxia immediately after feeding, which stabilizes hypoxia-inducible factor 2α (HIF2α) in liver. The transient postprandial increase in hepatic HIF2α attenuates glucagon signaling. Hepatocyte-specific disruption of HIF2α increases postprandial blood glucose and potentiates the glucagon response. Independent of insulin/AKT signaling, activation of hepatic HIF2α resulted in lower blood glucose, improved glucose tolerance, and decreased gluconeogenesis due to blunted hepatic glucagon action. Mechanistically, HIF2α abrogated glucagon-PKA signaling by activating cAMP-phosphodiesterases in a MEK/ERK-dependent manner. Repression of glucagon signaling by HIF2α ameliorated hyperglycemia in streptozotocin-induced diabetes and acute insulin-resistant animal models. This study reveals that HIF2α is essential for the acute postprandial regulation of hepatic glucagon signaling and suggests HIF2α as a potential therapeutic target in the treatment of diabetes.
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Affiliation(s)
- Sadeesh K Ramakrishnan
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Huabing Zhang
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Shogo Takahashi
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Brook Centofanti
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Sarvesh Periyasamy
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Kevin Weisz
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Zheng Chen
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Michael D Uhler
- Department of Biological Chemistry, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Liangyou Rui
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Frank J Gonzalez
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yatrik M Shah
- Departments of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Pathophysiology and treatment of pulmonary hypertension in sickle cell disease. Blood 2016; 127:820-8. [PMID: 26758918 DOI: 10.1182/blood-2015-08-618561] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/21/2015] [Indexed: 12/11/2022] Open
Abstract
Pulmonary hypertension affects ∼10% of adult patients with sickle cell disease (SCD), particularly those with the homozygous genotype. An increase in pulmonary artery systolic pressure, estimated noninvasively by echocardiography, helps identify SCD patients at risk for pulmonary hypertension, but definitive diagnosis requires right-heart catheterization. About half of SCD-related pulmonary hypertension patients have precapillary pulmonary hypertension with potential etiologies of (1) a nitric oxide deficiency state and vasculopathy consequent to intravascular hemolysis, (2) chronic pulmonary thromboembolism, or (3) upregulated hypoxic responses secondary to anemia, low O2 saturation, and microvascular obstruction. The remainder have postcapillary pulmonary hypertension secondary to left ventricular dysfunction. Although the pulmonary artery pressure in SCD patients with pulmonary hypertension is only moderately elevated, they have a markedly higher risk of death than patients without pulmonary hypertension. Guidelines for diagnosis and management of SCD-related pulmonary hypertension were published recently by the American Thoracic Society. Management of adults with sickle-related pulmonary hypertension is based on anticoagulation for those with thromboembolism; oxygen therapy for those with low oxygen saturation; treatment of left ventricular failure in those with postcapillary pulmonary hypertension; and hydroxyurea or transfusions to raise the hemoglobin concentration, reduce hemolysis, and prevent vaso-occlusive events that cause additional increases in pulmonary pressure. Randomized trials have not identified drugs to lower pulmonary pressure in SCD patients with precapillary pulmonary hypertension. Patients with hemodynamics of pulmonary arterial hypertension should be referred to specialized centers and considered for treatments known to be effective in other forms of pulmonary arterial hypertension. There have been reports that some of these treatments improve SCD-related pulmonary hypertension.
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Macías D, Fernández-Agüera MC, Bonilla-Henao V, López-Barneo J. Deletion of the von Hippel-Lindau gene causes sympathoadrenal cell death and impairs chemoreceptor-mediated adaptation to hypoxia. EMBO Mol Med 2015; 6:1577-92. [PMID: 25385837 PMCID: PMC4287976 DOI: 10.15252/emmm.201404153] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mutations of the von Hippel–Lindau (VHL) gene are associated with pheochromocytomas and paragangliomas, but the role of VHL in sympathoadrenal homeostasis is unknown. We generated mice lacking Vhl in catecholaminergic cells. They exhibited atrophy of the carotid body (CB), adrenal medulla, and sympathetic ganglia. Vhl-null animals had an increased number of adult CB stem cells, although the survival of newly generated neuron-like glomus cells was severely compromised. The effects of Vhl deficiency were neither prevented by pharmacological inhibition of prolyl hydroxylases or selective genetic down-regulation of prolyl hydroxylase-3, nor phenocopied by hypoxia inducible factor overexpression. Vhl-deficient animals appeared normal in normoxia but survived for only a few days in hypoxia, presenting with pronounced erythrocytosis, pulmonary edema, and right cardiac hypertrophy. Therefore, in the normal sympathoadrenal setting, Vhl deletion does not give rise to tumors but impairs development and plasticity of the peripheral O2-sensing system required for survival in hypoxic conditions.
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Affiliation(s)
- David Macías
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Mary Carmen Fernández-Agüera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Victoria Bonilla-Henao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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26
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Song J, Yoon D, Christensen RD, Horvathova M, Thiagarajan P, Prchal JT. HIF-mediated increased ROS from reduced mitophagy and decreased catalase causes neocytolysis. J Mol Med (Berl) 2015; 93:857-66. [PMID: 26017143 DOI: 10.1007/s00109-015-1294-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/15/2015] [Accepted: 05/12/2015] [Indexed: 02/02/2023]
Abstract
UNLABELLED During prolonged hypoxia, hypoxia-inducible factors (HIFs) mediate an increase in erythropoiesis, leading to an increased red blood cell (RBC) mass and polycythemia. Upon return to normoxia, the increased RBC mass is abruptly overcorrected by the preferential destruction of hypoxia-formed young RBCs, a phenomenon termed neocytolysis. The molecular and biochemical mechanisms involved in neocytolysis are unknown. We developed a murine model of neocytolysis by exposing mice to 12 % oxygen for 10 days followed by return to normoxia. Upon return to normoxia, there was excessive accumulation of reactive oxygen species (ROS) in RBCs from an increased reticulocyte mitochondrial mass correlating with decreased Bnip3L transcripts (Bnip3L mediates reticulocyte mitophagy) and reduced catalase activity. During hypoxia, upregulated miR-21 resulted in low catalase activity in young RBCs. Furthermore, neocytolysis was attenuated by antioxidants and plasma catalase and blunted in mice that had constitutively high expression of HIFs. Among human neonates studied, we report data supporting the existence of neocytolysis during the first week of life. Together, these experiments indicate that the major mechanisms causing neocytolysis involve (1) production of young RBCs with low catalase during hypoxia and (2) lysis of the young RBCs after return to normoxia, mediated by ROS from an increased mitochondrial mass. KEY MESSAGES We report a mouse model of neocytolysis. Neocytolysis is caused by excessive ROS formation mediated by HIF. ROS is generated from increased mitochondria in reticulocytes. Hypoxia-generated RBCs have low catalase and are preferentially destroyed. Reduced catalase is regulated by increased microRNA-21.
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Affiliation(s)
- Jihyun Song
- Division of Hematology, School of Medicine, University of Utah, Salt Lake City, UT, 84132, USA
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27
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Abstract
Since the Von Hippel-Lindau (VHL) disease tumour suppressor gene VHL was identified in 1993 as the genetic basis for a rare disorder, it has proved to be of wide medical and scientific interest. VHL tumour suppressor protein (pVHL) plays a key part in cellular oxygen sensing by targeting hypoxia-inducible factors for ubiquitylation and proteasomal degradation. Early inactivation of VHL is commonly seen in clear-cell renal cell carcinoma (ccRCC), and insights gained from the functional analysis of pVHL have provided the foundation for the routine treatment of advanced-stage ccRCC with novel targeted therapies. However, recent sequencing studies have identified additional driver genes that are involved in the pathogenesis of ccRCC. As our understanding of the importance of VHL matures, it is timely to review progress from its initial description to current knowledge of VHL biology, as well as future prospects for novel medical treatments for VHL disease and ccRCC.
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Affiliation(s)
- Lucy Gossage
- 1] Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [2] Department of Oncology, University of Cambridge, Box 193, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [3] Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge CB2 0RE, UK
| | - Tim Eisen
- 1] Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [2] Department of Oncology, University of Cambridge, Box 193, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Eamonn R Maher
- 1] Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK. [2] Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Box 238, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
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28
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Gossage L, Pires DEV, Olivera-Nappa Á, Asenjo J, Bycroft M, Blundell TL, Eisen T. An integrated computational approach can classify VHL missense mutations according to risk of clear cell renal carcinoma. Hum Mol Genet 2014; 23:5976-88. [PMID: 24969085 PMCID: PMC4204774 DOI: 10.1093/hmg/ddu321] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 05/25/2014] [Accepted: 06/17/2014] [Indexed: 12/26/2022] Open
Abstract
Mutations in the von Hippel-Lindau (VHL) gene are pathogenic in VHL disease, congenital polycythaemia and clear cell renal carcinoma (ccRCC). pVHL forms a ternary complex with elongin C and elongin B, critical for pVHL stability and function, which interacts with Cullin-2 and RING-box protein 1 to target hypoxia-inducible factor for polyubiquitination and proteasomal degradation. We describe a comprehensive database of missense VHL mutations linked to experimental and clinical data. We use predictions from in silico tools to link the functional effects of missense VHL mutations to phenotype. The risk of ccRCC in VHL disease is linked to the degree of destabilization resulting from missense mutations. An optimized binary classification system (symphony), which integrates predictions from five in silico methods, can predict the risk of ccRCC associated with VHL missense mutations with high sensitivity and specificity. We use symphony to generate predictions for risk of ccRCC for all possible VHL missense mutations and present these predictions, in association with clinical and experimental data, in a publically available, searchable web server.
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Affiliation(s)
- Lucy Gossage
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Douglas E V Pires
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Álvaro Olivera-Nappa
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK, Centre for Biochemical Engineering and Biotechnology, University of Chile, Beauchef 850, Santiago, Chile
| | - Juan Asenjo
- Centre for Biochemical Engineering and Biotechnology, University of Chile, Beauchef 850, Santiago, Chile
| | - Mark Bycroft
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Research Centre, Cambridge CB2 0QH, UK and
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Tim Eisen
- Department of Oncology, Cambridge University Hospitals NHS Foundation Trust, Box 193 (R4) Addenbrooke's Hospital, Cambridge Biomedical Campus, Hill's Road, Cambridge CB2 0QQ, UK
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29
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Couvé S, Ladroue C, Laine E, Mahtouk K, Guégan J, Gad S, Le Jeune H, Le Gentil M, Nuel G, Kim WY, Lecomte B, Pagès JC, Collin C, Lasne F, Benusiglio PR, Bressac-de Paillerets B, Feunteun J, Lazar V, Gimenez-Roqueplo AP, Mazure NM, Dessen P, Tchertanov L, Mole DR, Kaelin W, Ratcliffe P, Richard S, Gardie B. Genetic evidence of a precisely tuned dysregulation in the hypoxia signaling pathway during oncogenesis. Cancer Res 2014; 74:6554-64. [PMID: 25371412 PMCID: PMC5555745 DOI: 10.1158/0008-5472.can-14-1161] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The classic model of tumor suppression implies that malignant transformation requires full "two-hit" inactivation of a tumor-suppressor gene. However, more recent work in mice has led to the proposal of a "continuum" model that involves more fluid concepts such as gene dosage-sensitivity and tissue specificity. Mutations in the tumor-suppressor gene von Hippel-Lindau (VHL) are associated with a complex spectrum of conditions. Homozygotes or compound heterozygotes for the R200W germline mutation in VHL have Chuvash polycythemia, whereas heterozygous carriers are free of disease. Individuals with classic, heterozygous VHL mutations have VHL disease and are at high risk of multiple tumors (e.g., CNS hemangioblastomas, pheochromocytoma, and renal cell carcinoma). We report here an atypical family bearing two VHL gene mutations in cis (R200W and R161Q), together with phenotypic analysis, structural modeling, functional, and transcriptomic studies of these mutants in comparison with classical mutants involved in the different VHL phenotypes. We demonstrate that the complex pattern of disease manifestations observed in VHL syndrome is perfectly correlated with a gradient of VHL protein (pVHL) dysfunction in hypoxia signaling pathways. Thus, by studying naturally occurring familial mutations, our work validates in humans the "continuum" model of tumor suppression.
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Affiliation(s)
- Sophie Couvé
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Institut National de la Santé et de la Recherche Medicale (INSERM) U753, Gustave Roussy Cancer Campus, Villejuif, France. Centre Expert National Cancers Rares INCa "PREDIR" and Réseau National INCa "Maladie de VHL et prédispositions au cancer du rein," Service d'Urologie, Assistance publique, Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Charline Ladroue
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Institut National de la Santé et de la Recherche Medicale (INSERM) U753, Gustave Roussy Cancer Campus, Villejuif, France
| | - Elodie Laine
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), CNRS-ENS de Cachan, LabEx LERMIT, Cachan, France. Equipe de Génomique Analytique, Laboratoire de Biologie Computationnelle et Quantitative, CNRS-UPMC, UMR 7238, Paris, France
| | - Karène Mahtouk
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Institut National de la Santé et de la Recherche Medicale (INSERM) U753, Gustave Roussy Cancer Campus, Villejuif, France
| | - Justine Guégan
- Plate-forme de Génomique, Gustave Roussy Cancer Campus, Villejuif, France
| | - Sophie Gad
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Institut National de la Santé et de la Recherche Medicale (INSERM) U753, Gustave Roussy Cancer Campus, Villejuif, France. Centre Expert National Cancers Rares INCa "PREDIR" and Réseau National INCa "Maladie de VHL et prédispositions au cancer du rein," Service d'Urologie, Assistance publique, Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Hélène Le Jeune
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Institut National de la Santé et de la Recherche Medicale (INSERM) U753, Gustave Roussy Cancer Campus, Villejuif, France
| | - Marion Le Gentil
- Plate-forme de Génomique, Gustave Roussy Cancer Campus, Villejuif, France
| | - Gregory Nuel
- Mathématiques Appliquées à Paris 5 (MAP5), UMR CNRS 8145, Université Paris Descartes, Paris, France
| | - William Y Kim
- Lineberger Comprehensive Cancer Center University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | | | - Jean-Christophe Pagès
- INSERM U966, Université François Rabelais de Tours, Faculté de Médecine, Tours, France
| | - Christine Collin
- INSERM U966, Université François Rabelais de Tours, Faculté de Médecine, Tours, France
| | - Françoise Lasne
- Département des analyses, Agence Française de Lutte contre le Dopage (AFLD), Chatenay-Malabry, France
| | - Patrick R Benusiglio
- Département de Médecine Oncologique, Gustave Roussy Cancer Campus, Villejuif, France. Centre Expert National Cancers Rares INCa "PREDIR" and Réseau National INCa "Maladie de VHL et prédispositions au cancer du rein," Service d'Urologie, Assistance publique, Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Brigitte Bressac-de Paillerets
- Centre Expert National Cancers Rares INCa "PREDIR" and Réseau National INCa "Maladie de VHL et prédispositions au cancer du rein," Service d'Urologie, Assistance publique, Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France. Service de Génétique, Gustave Roussy Cancer Campus, Villejuif, France
| | - Jean Feunteun
- Laboratoire Stabilité génétique et Oncogénèse, UMR CNRS 8200, Gustave Roussy Cancer Campus, Villejuif, France
| | - Vladimir Lazar
- Plate-forme de Génomique, Gustave Roussy Cancer Campus, Villejuif, France
| | - Anne-Paule Gimenez-Roqueplo
- Centre Expert National Cancers Rares INCa "PREDIR" and Réseau National INCa "Maladie de VHL et prédispositions au cancer du rein," Service d'Urologie, Assistance publique, Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France. Assistance Publique, Hôpitaux de Paris, Hôpital européen Georges Pompidou, Service de Génétique, Paris, France. INSERM UMR970, Paris-Cardiovascular Research Center at HEGP, Paris, France. Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Nathalie M Mazure
- Institute for Research on Cancer and Ageing of Nice (IRCAN), UMR CNRS 7284, INSERM U1081, UNS, Nice, France
| | - Philippe Dessen
- Plate-forme de Génomique, Gustave Roussy Cancer Campus, Villejuif, France
| | - Luba Tchertanov
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), CNRS-ENS de Cachan, LabEx LERMIT, Cachan, France
| | - David R Mole
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, United Kingdom
| | | | - Peter Ratcliffe
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, United Kingdom
| | - Stéphane Richard
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Institut National de la Santé et de la Recherche Medicale (INSERM) U753, Gustave Roussy Cancer Campus, Villejuif, France. Centre Expert National Cancers Rares INCa "PREDIR" and Réseau National INCa "Maladie de VHL et prédispositions au cancer du rein," Service d'Urologie, Assistance publique, Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France. Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, Paris, France.
| | - Betty Gardie
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes (EPHE), Villejuif, France. Unité Mixte de Recherche (UMR) INSERM U892, CNRS 6299, Centre de Recherche en Cancérologie Nantes/Angers (CRCNA), Université de Nantes, Nantes, France.
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30
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Mimicking hypoxia to treat anemia: HIF-stabilizer BAY 85-3934 (Molidustat) stimulates erythropoietin production without hypertensive effects. PLoS One 2014; 9:e111838. [PMID: 25392999 PMCID: PMC4230943 DOI: 10.1371/journal.pone.0111838] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/01/2014] [Indexed: 11/30/2022] Open
Abstract
Oxygen sensing by hypoxia-inducible factor prolyl hydroxylases (HIF-PHs) is the dominant regulatory mechanism of erythropoietin (EPO) expression. In chronic kidney disease (CKD), impaired EPO expression causes anemia, which can be treated by supplementation with recombinant human EPO (rhEPO). However, treatment can result in rhEPO levels greatly exceeding the normal physiological range for endogenous EPO, and there is evidence that this contributes to hypertension in patients with CKD. Mimicking hypoxia by inhibiting HIF-PHs, thereby stabilizing HIF, is a novel treatment concept for restoring endogenous EPO production. HIF stabilization by oral administration of the HIF-PH inhibitor BAY 85-3934 (molidustat) resulted in dose-dependent production of EPO in healthy Wistar rats and cynomolgus monkeys. In repeat oral dosing of BAY 85-3934, hemoglobin levels were increased compared with animals that received vehicle, while endogenous EPO remained within the normal physiological range. BAY 85-3934 therapy was also effective in the treatment of renal anemia in rats with impaired kidney function and, unlike treatment with rhEPO, resulted in normalization of hypertensive blood pressure in a rat model of CKD. Notably, unlike treatment with the antihypertensive enalapril, the blood pressure normalization was achieved without a compensatory activation of the renin–angiotensin system. Thus, BAY 85-3934 may provide an approach to the treatment of anemia in patients with CKD, without the increased risk of adverse cardiovascular effects seen for patients treated with rhEPO. Clinical studies are ongoing to investigate the effects of BAY 85-3934 therapy in patients with renal anemia.
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Gardie B, Percy MJ, Hoogewijs D, Chowdhury R, Bento C, Arsenault PR, Richard S, Almeida H, Ewing J, Lambert F, McMullin MF, Schofield CJ, Lee FS. The role of PHD2 mutations in the pathogenesis of erythrocytosis. HYPOXIA 2014; 2:71-90. [PMID: 27774468 PMCID: PMC5045058 DOI: 10.2147/hp.s54455] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The transcription of the erythropoietin (EPO) gene is tightly regulated by the hypoxia response pathway to maintain oxygen homeostasis. Elevations in serum EPO level may be reflected in an augmentation in the red cell mass, thereby causing erythrocytosis. Studies on erythrocytosis have provided insights into the function of the oxygen-sensing pathway and the critical proteins involved in the regulation of EPO transcription. The α subunits of the hypoxia-inducible transcription factor are hydroxylated by three prolyl hydroxylase domain (PHD) enzymes, which belong to the iron and 2-oxoglutarate-dependent oxygenase superfamily. Sequence analysis of the genes encoding the PHDs in patients with erythrocytosis has revealed heterozygous germline mutations only occurring in Egl nine homolog 1 (EGLN1, also known as PHD2), the gene that encodes PHD2. To date, 24 different EGLN1 mutations comprising missense, frameshift, and nonsense mutations have been described. The phenotypes associated with the patients carrying these mutations are fairly homogeneous and typically limited to erythrocytosis with normal to elevated EPO. However, exceptions exist; for example, there is one case with development of concurrent paraganglioma (PHD2-H374R). Analysis of the erythrocytosis-associated PHD2 missense mutations has shown heterogeneous results. Structural studies reveal that mutations can affect different domains of PHD2. Some are close to the hypoxia-inducible transcription factor α/2-oxoglutarate or the iron binding sites for PHD2. In silico studies demonstrate that the mutations do not always affect fully conserved residues. In vitro and in cellulo studies showed varying effects of the mutations, ranging from mild effects to severe loss of function. The exact mechanism of a potential tumor-suppressor role for PHD2 still needs to be elucidated. A knockin mouse model expressing the first reported PHD2-P317R mutation recapitulates the phenotype observed in humans (erythrocytosis with inappropriately normal serum EPO levels) and demonstrates that haploinsufficiency and partial deregulation of PHD2 is sufficient to cause erythrocytosis.
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Affiliation(s)
- Betty Gardie
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes, Villejuif; Unité Mixte de Recherche, Institut national de la santé et de la recherche médicale U892, Centre national de la recherche scientifique 6299, Centre de Recherche en Cancérologie Nantes/Angers, Université de Nantes, Nantes, France
| | - Melanie J Percy
- Department of Haematology, Belfast City Hospital, Belfast, UK
| | - David Hoogewijs
- Institute of Physiology and Zürich Center for Integrative Human Physiology, University of Zürich, Zürich, Switzerland
| | - Rasheduzzaman Chowdhury
- Department of Chemistry and Oxford Centre for Integrative Systems Biology, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Celeste Bento
- Department of Hematology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Patrick R Arsenault
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Stéphane Richard
- Laboratoire de Génétique Oncologique de l'Ecole Pratique des Hautes Etudes, Villejuif; Institut national de la santé et de la recherche médicale U753, Institut de cancérologie Gustave Roussy (IGR), Villejuif, France; Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France
| | - Helena Almeida
- Department of Hematology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | | | - Frédéric Lambert
- Center for Human Genetics, Pathology Institute, UniLab-Lg, Molecular Haemato-Oncology Unit, CHU of Liege, Liege, Belgium
| | | | - Christopher J Schofield
- Department of Chemistry and Oxford Centre for Integrative Systems Biology, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Frank S Lee
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Zhang DL, Ghosh MC, Rouault TA. The physiological functions of iron regulatory proteins in iron homeostasis - an update. Front Pharmacol 2014; 5:124. [PMID: 24982634 PMCID: PMC4056636 DOI: 10.3389/fphar.2014.00124] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 05/10/2014] [Indexed: 01/15/2023] Open
Abstract
Iron regulatory proteins (IRPs) regulate the expression of genes involved in iron metabolism by binding to RNA stem-loop structures known as iron responsive elements (IREs) in target mRNAs. IRP binding inhibits the translation of mRNAs that contain an IRE in the 5′untranslated region of the transcripts, and increases the stability of mRNAs that contain IREs in the 3′untranslated region of transcripts. By these mechanisms, IRPs increase cellular iron absorption and decrease storage and export of iron to maintain an optimal intracellular iron balance. There are two members of the mammalian IRP protein family, IRP1 and IRP2, and they have redundant functions as evidenced by the embryonic lethality of the mice that completely lack IRP expression (Irp1-/-/Irp2-/- mice), which contrasts with the fact that Irp1-/- and Irp2-/- mice are viable. In addition, Irp2-/- mice also display neurodegenerative symptoms and microcytic hypochromic anemia, suggesting that IRP2 function predominates in the nervous system and erythropoietic homeostasis. Though the physiological significance of IRP1 had been unclear since Irp1-/- animals were first assessed in the early 1990s, recent studies indicate that IRP1 plays an essential function in orchestrating the balance between erythropoiesis and bodily iron homeostasis. Additionally, Irp1-/- mice develop pulmonary hypertension, and they experience sudden death when maintained on an iron-deficient diet, indicating that IRP1 has a critical role in the pulmonary and cardiovascular systems. This review summarizes recent progress that has been made in understanding the physiological roles of IRP1 and IRP2, and further discusses the implications for clinical research on patients with idiopathic polycythemia, pulmonary hypertension, and neurodegeneration.
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Affiliation(s)
- De-Liang Zhang
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute of Health Bethesda, MD, USA
| | - Manik C Ghosh
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute of Health Bethesda, MD, USA
| | - Tracey A Rouault
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute of Health Bethesda, MD, USA
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Zhang X, Zhang W, Ma SF, Desai AA, Saraf S, Miasniakova G, Sergueeva A, Ammosova T, Xu M, Nekhai S, Abbasi T, Casanova NG, Steinberg MH, Baldwin CT, Sebastiani P, Prchal JT, Kittles R, Garcia JGN, Machado RF, Gordeuk VR. Hypoxic response contributes to altered gene expression and precapillary pulmonary hypertension in patients with sickle cell disease. Circulation 2014; 129:1650-8. [PMID: 24515990 DOI: 10.1161/circulationaha.113.005296] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND We postulated that the hypoxic response in sickle cell disease (SCD) contributes to altered gene expression and pulmonary hypertension, a complication associated with early mortality. METHODS AND RESULTS To identify genes regulated by the hypoxic response and not other effects of chronic anemia, we compared expression variation in peripheral blood mononuclear cells from 13 subjects with SCD with hemoglobin SS genotype and 15 subjects with Chuvash polycythemia (VHL(R200W) homozygotes with constitutive upregulation of hypoxia-inducible factors in the absence of anemia or hypoxia). At a 5% false discovery rate, 1040 genes exhibited >1.15-fold change in both conditions; 297 were upregulated and 743 downregulated including MAPK8 encoding a mitogen-activated protein kinase important for apoptosis, T-cell differentiation, and inflammatory responses. Association mapping with a focus on local regulatory polymorphisms in 61 patients with SCD identified expression quantitative trait loci for 103 of these hypoxia response genes. In a University of Illinois SCD cohort, the A allele of a MAPK8 expression quantitative trait locus, rs10857560, was associated with precapillary pulmonary hypertension defined as mean pulmonary artery pressure ≥25 mm Hg and pulmonary capillary wedge pressure ≤15 mm Hg at right heart catheterization (allele frequency, 0.66; odds ratio, 13.8; n=238). This association was confirmed in an independent Walk-Treatment of Pulmonary Hypertension and Sickle Cell Disease With Sildenafil Therapy cohort (allele frequency, 0.65; odds ratio, 11.3; n=519). The homozygous AA genotype of rs10857560 was associated with decreased MAPK8 expression and present in all 14 of the identified precapillary pulmonary hypertension cases among the combined 757 patients. CONCLUSIONS Our study demonstrates a prominent hypoxic transcription component in SCD and a MAPK8 expression quantitative trait locus associated with precapillary pulmonary hypertension.
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Affiliation(s)
- Xu Zhang
- Comprehensive Sickle Cell Center, Section of Hematology/Oncology (X.Z., S.S., V.R.G.), Section of Cardiology (A.A.D.), and Section of Pulmonary, Critical Care, and Sleep Medicine (J.G.N.G., R.F.M.), Department of Medicine, Institute of Human Genetics (W.Z., R.K.), Department of Pediatrics (W.Z.), and Institute for Personalized Respiratory Medicine (A.A.D., T.A., N.G.C., J.G.N.G., R.F.M.), University of Illinois at Chicago, Chicago, IL; Section of Pulmonary/Critical Care, Department of Medicine, University of Chicago, Chicago, IL (S-F.M.); Chuvash Republic Clinical Hospital 2, Cheboksary, Russia (G.M.); Cheboksary Children's Hospital, Cheboksary, Russia (A.S.); Center for Sickle Cell Disease, Howard University, Washington, DC (T.A., M.X., S.N.); Department of Medicine, Boston University School of Medicine, Boston, MA (M.H.S., C.T.B.); Department of Biostatistics, Boston University School of Public Health, Boston, MA (P.S.); Hematology Division, University of Utah, Salt Lake City, UT (J.T.P.)
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Effect of congenital upregulation of hypoxia inducible factors on percentage of fetal hemoglobin in the blood. Blood 2013; 122:3088-9. [PMID: 24159170 DOI: 10.1182/blood-2013-07-515973] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Arsenault PR, Pei F, Lee R, Kerestes H, Percy MJ, Keith B, Simon MC, Lappin TRJ, Khurana TS, Lee FS. A knock-in mouse model of human PHD2 gene-associated erythrocytosis establishes a haploinsufficiency mechanism. J Biol Chem 2013; 288:33571-33584. [PMID: 24121508 DOI: 10.1074/jbc.m113.482364] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The central pathway for controlling red cell mass is the PHD (prolyl hydroxylase domain protein):hypoxia-inducible factor (HIF) pathway. HIF, which is negatively regulated by PHD, activates numerous genes, including ones involved in erythropoiesis, such as the ERYTHROPOIETIN (EPO) gene. Recent studies have implicated PHD2 as the key PHD isoform regulating red cell mass. Studies of humans have identified erythrocytosis-associated, heterozygous point mutations in the PHD2 gene. A key question concerns the mechanism by which human mutations lead to phenotypes. In the present report, we generated and characterized a mouse line in which a P294R knock-in mutation has been introduced into the mouse Phd2 locus to model the first reported human PHD2 mutation (P317R). Phd2(P294R/+) mice display a degree of erythrocytosis equivalent to that seen in Phd2(+/-) mice. The Phd2(P294R/+)-associated erythrocytosis is reversed in a Hif2a(+/-), but not a Hif1a(+/-) background. Additional studies using various conditional knock-outs of Phd2 reveal that erythrocytosis can be induced by homozygous and heterozygous knock-out of Phd2 in renal cortical interstitial cells using a Pax3-Cre transgene or by homozygous knock-out of Phd2 in hematopoietic progenitors driven by a Vav1-Cre transgene. These studies formally prove that a missense mutation in PHD2 is the cause of the erythrocytosis, show that this occurs through haploinsufficiency, and point to multifactorial control of red cell mass by PHD2.
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Affiliation(s)
- Patrick R Arsenault
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Fei Pei
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Rebecca Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Heddy Kerestes
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Melanie J Percy
- Department of Haematology, Belfast City Hospital, Belfast, Northern Ireland BT9 7AB, United Kingdom
| | - Brian Keith
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - M Celeste Simon
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104; Howard Hughes Medical Institute, Philadelphia, Pennsylvania 19104
| | - Terence R J Lappin
- Centre for Cancer Research and Cell Biology, Queen's University, Belfast, Northern Ireland BT9 7BL, United Kingdom
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Frank S Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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36
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Slingo ME, Turner PJ, Christian HC, Buckler KJ, Robbins PA. The von Hippel-Lindau Chuvash mutation in mice causes carotid-body hyperplasia and enhanced ventilatory sensitivity to hypoxia. J Appl Physiol (1985) 2013; 116:885-92. [PMID: 24030664 PMCID: PMC3972741 DOI: 10.1152/japplphysiol.00530.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The hypoxia-inducible factor (HIF) family of transcription factors coordinates diverse cellular and systemic responses to hypoxia. Chuvash polycythemia (CP) is an autosomal recessive disorder in humans in which there is impaired oxygen-dependent degradation of HIF, resulting in long-term systemic elevation of HIF levels at normal oxygen tensions. CP patients demonstrate the characteristic features of ventilatory acclimatization to hypoxia, namely, an elevated baseline ventilation and enhanced acute hypoxic ventilatory response (AHVR). We investigated the ventilatory and carotid-body phenotype of a mouse model of CP, using whole-body plethysmography, immunohistochemistry, and electron microscopy. In keeping with studies in humans, CP mice had elevated ventilation in euoxia and a significantly exaggerated AHVR when exposed to 10% oxygen, with or without the addition of 3% carbon dioxide. Carotid-body immunohistochemistry demonstrated marked hyperplasia of the oxygen-sensing type I cells, and the cells themselves appeared enlarged with more prominent nuclei. This hypertrophy was confirmed by electron microscopy, which also revealed that the type I cells contained an increased number of mitochondria, enlarged dense-cored vesicles, and markedly expanded rough endoplasmic reticulum. The morphological and ultrastructural changes seen in the CP mouse carotid body are strikingly similar to those observed in animals exposed to chronic hypoxia. Our study demonstrates that the HIF pathway plays a major role, not only in regulating both euoxic ventilatory control and the sensitivity of the response to hypoxia, but also in determining the morphology of the carotid body.
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Affiliation(s)
- Mary E Slingo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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37
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Zhang X, Zhang W, Ma SF, Miasniakova G, Sergueeva A, Ammosova T, Xu M, Nekhai S, Nourai M, Wade MS, Prchal JT, Garcia JGN, Machado RF, Gordeuk VR. Iron deficiency modifies gene expression variation induced by augmented hypoxia sensing. Blood Cells Mol Dis 2013; 52:35-45. [PMID: 23993337 DOI: 10.1016/j.bcmd.2013.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 07/19/2013] [Indexed: 01/20/2023]
Abstract
In congenital Chuvash polycythemia (CP), VHL(R200W) homozygosity leads to elevated hypoxia inducible factor (HIF) levels at normoxia. CP is often treated by phlebotomy resulting in iron deficiency, permitting us to examine the separate and synergistic effects of iron deficiency and HIF signaling on gene expression. We compared peripheral blood mononuclear cell gene expression profiles of eight VHL(R200W) homozygotes with 17 wildtype individuals with normal iron status and found 812 up-regulated and 2120 down-regulated genes at false discovery rate of 0.05. Among differential genes we identified three major gene regulation modules involving induction of innate immune responses, alteration of carbohydrate and lipid metabolism, and down-regulation of cell proliferation, stress-induced apoptosis and T-cell activation. These observations suggest molecular mechanisms for previous observations in CP of lower blood sugar without increased insulin and low oncogenic potential. Studies including 16 additional VHL(R200W) homozygotes with low ferritin indicated that iron deficiency enhanced the induction effect of VHL(R200W) for 50 genes including hemoglobin synthesis loci but suppressed the effect for 107 genes enriched for HIF-2 targets. This pattern is consistent with potentiation of HIF-1α protein stability by iron deficiency but a trend for down-regulation of HIF-2α translation by iron deficiency overriding an increase in HIF-2α protein stability.
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Affiliation(s)
- Xu Zhang
- Comprehensive Sickle Cell Center, Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Wei Zhang
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL, USA.,Institute of Human Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Shwu-Fan Ma
- Section of Pulmonary/Critical Care, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Galina Miasniakova
- Chuvash Republic Clinical Hospital 2, Cheboksary, Russian Federation, Howard University, Washington, DC
| | - Adelina Sergueeva
- Cheboksary Children's Hospital, Cheboksary, Russian Federation, Howard University, Washington, DC
| | - Tatiana Ammosova
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Min Xu
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Sergei Nekhai
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Mehdi Nourai
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Michael S Wade
- Section of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.,Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Josef T Prchal
- Departments of Medicine, Pathology and Genetics, University of Utah and VAH
| | - Joe G N Garcia
- Section of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.,Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Roberto F Machado
- Section of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.,Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Victor R Gordeuk
- Comprehensive Sickle Cell Center, Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Novel homozygous VHL mutation in exon 2 is associated with congenital polycythemia but not with cancer. Blood 2013; 121:3918-24. [PMID: 23538339 DOI: 10.1182/blood-2012-11-469296] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Germline von Hippel-Lindau (VHL) gene mutations underlie dominantly inherited familial VHL tumor syndrome comprising a predisposition for renal cell carcinoma, pheochromocytoma/paraganglioma, cerebral hemangioblastoma, and endolymphatic sac tumors. However, recessively inherited congenital polycythemia, exemplified by Chuvash polycythemia, has been associated with 2 separate 3' VHL gene mutations in exon 3. It was proposed that different positions of loss-of-function VHL mutations are associated with VHL syndrome cancer predisposition and only C-terminal domain-encoding VHL mutations would cause polycythemia. However, now we describe a new homozygous VHL exon 2 mutation of the VHL gene:(c.413C>T):P138L, which is associated in the affected homozygote with congenital polycythemia but not in her, or her-heterozygous relatives, with cancer or other VHL syndrome tumors. We show that VHL(P138L) has perturbed interaction with hypoxia-inducible transcription factor (HIF)1α. Further, VHL(P138L) protein has decreased stability in vitro. Similarly to what was reported in Chuvash polycythemia and some other instances of HIFs upregulation, VHL(P138L) erythroid progenitors are hypersensitive to erythropoietin. Interestingly, the level of RUNX1/AML1 and NF-E2 transcripts that are specifically upregulated in acquired polycythemia vera were also upregulated in VHL(P138L) granulocytes.
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Abstract
During the past century, few proteins have matched erythropoietin (Epo) in capturing the imagination of physiologists, molecular biologists, and, more recently, physicians and patients. Its appeal rests on its commanding role as the premier erythroid cytokine, the elegant mechanism underlying the regulation of its gene, and its remarkable impact as a therapeutic agent, arguably the most successful drug spawned by the revolution in recombinant DNA technology. This concise review will begin with a synopsis of the colorful history of this protein, culminating in its purification and molecular cloning. It then covers in more detail the contemporary understanding of Epo's physiology as well as its structure and interaction with its receptor. A major part of this article focuses on the regulation of the Epo gene and the discovery of HIF, a transcription factor that plays a cardinal role in molecular adaptation to hypoxia. In the concluding section, a synopsis of Epo's role in disorders of red blood cell production will be followed by an assessment of the remarkable impact of Epo therapy in the treatment of anemias, as well as concerns that provide a strong impetus for the development of even safer and more effective treatment.
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Affiliation(s)
- H Franklin Bunn
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Tomasic NL, Piterkova L, Huff C, Bilic E, Yoon D, Miasnikova GY, Sergueeva AI, Niu X, Nekhai S, Gordeuk V, Prchal JT. The phenotype of polycythemia due to Croatian homozygous VHL (571C>G:H191D) mutation is different from that of Chuvash polycythemia (VHL 598C>T:R200W). Haematologica 2013; 98:560-7. [PMID: 23403324 DOI: 10.3324/haematol.2012.070508] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mutations of VHL (a negative regulator of hypoxia-inducible factors) have position-dependent distinct cancer phenotypes. Only two known inherited homozygous VHL mutations exist and they cause polycythemia: Chuvash R200W and Croatian H191D. We report a second polycythemic Croatian H191D homozygote distantly related to the first propositus. Three generations of both families were genotyped for analysis of shared ancestry. Biochemical and molecular tests were performed to better define their phenotypes, with an emphasis on a comparison with Chuvash polycythemia. The VHL H191D mutation did not segregate in the family defined by the known common ancestors of the two subjects, suggesting a high prevalence in Croatians, but haplotype analysis indicated an undocumented common ancestor ∼six generations ago as the founder of this mutation. We show that erythropoietin levels in homozygous VHL H191D individuals are higher than in VHL R200W patients of similar ages, and their native erythroid progenitors, unlike Chuvash R200W, are not hypersensitive to erythropoietin. This observation contrasts with a report suggesting that polycythemia in VHL R200W and H191D homozygotes is due to the loss of JAK2 regulation from VHL R200W and H191D binding to SOCS1. In conclusion, our studies further define the hematologic phenotype of VHL H191D and provide additional evidence for phenotypic heterogeneity associated with the positional effects of VHL mutations.
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Ghosh MC, Zhang DL, Jeong SY, Kovtunovych G, Ollivierre-Wilson H, Noguchi A, Tu T, Senecal T, Robinson G, Crooks DR, Tong WH, Ramaswamy K, Singh A, Graham BB, Tuder RM, Yu ZX, Eckhaus M, Lee J, Springer DA, Rouault TA. Deletion of iron regulatory protein 1 causes polycythemia and pulmonary hypertension in mice through translational derepression of HIF2α. Cell Metab 2013; 17:271-81. [PMID: 23395173 PMCID: PMC3569856 DOI: 10.1016/j.cmet.2012.12.016] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/12/2012] [Accepted: 12/31/2012] [Indexed: 01/07/2023]
Abstract
Iron regulatory proteins (Irps) 1 and 2 posttranscriptionally control the expression of transcripts that contain iron-responsive element (IRE) sequences, including ferritin, ferroportin, transferrin receptor, and hypoxia-inducible factor 2α (HIF2α). We report here that mice with targeted deletion of Irp1 developed pulmonary hypertension and polycythemia that was exacerbated by a low-iron diet. Hematocrits increased to 65% in iron-starved mice, and many polycythemic mice died of abdominal hemorrhages. Irp1 deletion enhanced HIF2α protein expression in kidneys of Irp1(-/-) mice, which led to increased erythropoietin (EPO) expression, polycythemia, and concomitant tissue iron deficiency. Increased HIF2α expression in pulmonary endothelial cells induced high expression of endothelin-1, likely contributing to the pulmonary hypertension of Irp1(-/-) mice. Our results reveal why anemia is an early physiological consequence of iron deficiency, highlight the physiological significance of Irp1 in regulating erythropoiesis and iron distribution, and provide important insights into the molecular pathogenesis of pulmonary hypertension.
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Affiliation(s)
- Manik C Ghosh
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
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Abstract
A classic physiologic response to systemic hypoxia is the increase in red blood cell production. Hypoxia-inducible factors (HIFs) orchestrate this response by inducing cell-type specific gene expression changes that result in increased erythropoietin (EPO) production in kidney and liver, in enhanced iron uptake and utilization and in adjustments of the bone marrow microenvironment that facilitate erythroid progenitor maturation and proliferation. In particular HIF-2 has emerged as the transcription factor that regulates EPO synthesis in the kidney and liver and plays a critical role in the regulation of intestinal iron uptake. Its key function in the hypoxic regulation of erythropoiesis is underscored by genetic studies in human populations that live at high-altitude and by mutational analysis of patients with familial erythrocytosis. This review provides a perspective on recent insights into HIF-controlled erythropoiesis and iron metabolism, and examines cell types that have EPO-producing capability. Furthermore, the review summarizes clinical syndromes associated with mutations in the O(2)-sensing pathway and the genetic changes that occur in high altitude natives. The therapeutic potential of pharmacologic HIF activation for the treatment of anemia is discussed.
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Affiliation(s)
- Volker H Haase
- Department of Medicine, Vanderbilt School of Medicine, Nashville, TN, USA.
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Liu Q, Davidoff O, Niss K, Haase VH. Hypoxia-inducible factor regulates hepcidin via erythropoietin-induced erythropoiesis. J Clin Invest 2012; 122:4635-44. [PMID: 23114598 DOI: 10.1172/jci63924] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 09/06/2012] [Indexed: 02/06/2023] Open
Abstract
Iron demand in bone marrow increases when erythropoiesis is stimulated by hypoxia via increased erythropoietin (EPO) synthesis in kidney and liver. Hepcidin, a small polypeptide produced by hepatocytes, plays a central role in regulating iron uptake by promoting internalization and degradation of ferroportin, the only known cellular iron exporter. Hypoxia suppresses hepcidin, thereby enhancing intestinal iron uptake and release from internal stores. While HIF, a central mediator of cellular adaptation to hypoxia, directly regulates renal and hepatic EPO synthesis under hypoxia, the molecular basis of hypoxia/HIF-mediated hepcidin suppression in the liver remains unclear. Here, we used a genetic approach to disengage HIF activation from EPO synthesis and found that HIF-mediated suppression of the hepcidin gene (Hamp1) required EPO induction. EPO induction was associated with increased erythropoietic activity and elevated serum levels of growth differentiation factor 15. When erythropoiesis was inhibited pharmacologically, Hamp1 was no longer suppressed despite profound elevations in serum EPO, indicating that EPO by itself is not directly involved in Hamp1 regulation. Taken together, we provide in vivo evidence that Hamp1 suppression by the HIF pathway occurs indirectly through stimulation of EPO-induced erythropoiesis.
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Affiliation(s)
- Qingdu Liu
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Decreased serum glucose and glycosylated hemoglobin levels in patients with Chuvash polycythemia: a role for HIF in glucose metabolism. J Mol Med (Berl) 2012; 91:59-67. [PMID: 23015148 DOI: 10.1007/s00109-012-0961-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/17/2012] [Accepted: 09/17/2012] [Indexed: 12/22/2022]
Abstract
In Chuvash polycythemia, a homozygous 598C>T mutation in the von Hippel-Lindau gene (VHL) leads to an R200W substitution in VHL protein, impaired degradation of α-subunits of hypoxia-inducible factor (HIF)-1 and HIF-2, and augmented hypoxic responses during normoxia. Chronic hypoxia of high altitude is associated with decreased serum glucose and insulin concentrations. Other investigators reported that HIF-1 promotes cellular glucose uptake by increased expression of GLUT1 and increased glycolysis by increased expression of enzymes such as PDK. On the other hand, inactivation of Vhl in murine liver leads to hypoglycemia associated with a HIF-2-related decrease in the expression of the gluconeogenic enzyme genes Pepck, G6pc, and Glut2. We therefore hypothesized that glucose concentrations are decreased in individuals with Chuvash polycythemia. We found that 88 Chuvash VHL ( R200W ) homozygotes had lower random glucose and glycosylated hemoglobin A1c levels than 52 Chuvash subjects with wild-type VHL alleles. Serum metabolomics revealed higher glycerol and citrate levels in the VHL ( R200W ) homozygotes. We expanded these observations in VHL ( R200W ) homozygote mice and found that they had lower fasting glucose values and lower glucose excursions than wild-type control mice but no change in fasting insulin concentrations. Hepatic expression of Glut2 and G6pc, but not Pdk2, was decreased, and skeletal muscle expression of Glut1, Pdk1, and Pdk4 was increased. These results suggest that both decreased hepatic gluconeogenesis and increased skeletal uptake and glycolysis contribute to the decreased glucose concentrations. Further study is needed to determine whether pharmacologically manipulating HIF expression might be beneficial for treatment of diabetic patients.
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Park S, Chan CC. Von Hippel-Lindau disease (VHL): a need for a murine model with retinal hemangioblastoma. Histol Histopathol 2012; 27:975-84. [PMID: 22763871 PMCID: PMC3407271 DOI: 10.14670/hh-27.975] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Von Hippel-Lindau (VHL) disease is a highly penetrant autosomal dominant systemic malignancy that gives rise to cystic and highly vascularized tumors in a constellation of organs. Patients with VHL disease commonly present with hemangioblastomas in the central nervous system and the eye while other manifestations include pheochromocytoma, clear cell renal cell carcinoma, endolymphatic sac tumors of the middle ear, pancreatic cystadenomas, epididymal and broad ligament cystadenomas. Animal models inactivating the VHL gene product in various organ tissues have been constructed over the past 15 years to parse its HIF-associated mechanisms and its link to tumorigenesis. These models, despite advancing our understanding the molecular role of VHL, are by and large unable to recapitulate the more common features of human VHL disease. Up to date, no model exists that develop retinal hemangioblastomas, the most common clinical manifestation. The purpose of this review is: (1) to discuss the need for an ocular VHL model, (2) to review the animal models that recapitulate clinical VHL disease and (3) to propose potential mechanisms of tumorigenesis for the development of ocular VHL.
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Affiliation(s)
- Stanley Park
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Chi-Chao Chan
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
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Abstract
Over the last two decades molecular studies of inherited tumor syndromes that are associated with the development of kidney cancer have led to the identification of genes and biochemical pathways, which play key roles in the malignant transformation of renal epithelial cells. Some of these findings have broad biological impact and extend beyond renal cancer. This review's focus is on the von Hippel-Lindau (VHL)/hypoxia-inducible factor (HIF) oxygen-sensing pathway and its role in physiology, energy metabolism and tumorigenesis.
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Affiliation(s)
- Volker H Haase
- Department of Medicine, Vanderbilt School of Medicine, Nashville, TN 37232, USA.
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Criswell KA, Cook JC, Wojcinski Z, Pegg D, Herman J, Wesche D, Giddings J, Brady JT, Anderson T. Mode of action associated with development of hemangiosarcoma in mice given pregabalin and assessment of human relevance. Toxicol Sci 2012; 128:57-71. [PMID: 22539620 DOI: 10.1093/toxsci/kfs149] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pregabalin increased the incidence of hemangiosarcomas in carcinogenicity studies of 2-year mice but was not tumorigenic in rats. Serum bicarbonate increased within 24 h of pregabalin administration in mice and rats. Rats compensated appropriately, but mice developed metabolic alkalosis and increased blood pH. Local tissue hypoxia and increased endothelial cell proliferation were also confirmed in mice alone. The combination of hypoxia and sustained increases in endothelial cell proliferation, angiogenic growth factors, dysregulated erythropoiesis, and macrophage activation is proposed as the key event in the mode of action (MOA) for hemangiosarcoma formation. Hemangiosarcomas occur spontaneously in untreated control mice but occur only rarely in humans. The International Programme on Chemical Safety and International Life Sciences Institute developed a Human Relevance Framework (HRF) analysis whereby presence or absence of key events can be used to assess human relevance. The HRF combines the MOA with an assessment of biologic plausibility in humans to assess human relevance. This manuscript compares the proposed MOA with Hill criteria, a component of the HRF, for strength, consistency, specificity, temporality, and dose response, with an assessment of key biomarkers in humans, species differences in response to disease conditions, and spontaneous incidence of hemangiosarcoma to evaluate human relevance. Lack of key biomarker events in the MOA in rats, monkeys, and humans supports a species-specific process and demonstrates that the tumor findings in mice are not relevant to humans at the clinical dose of pregabalin. Based on this collective dataset, clinical use of pregabalin would not pose an increased risk for hemangiosarcoma to humans.
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Affiliation(s)
- Kay A Criswell
- Pfizer Worldwide Research & Development, Drug Safety Research & Development, Groton, Connecticut 06340, USA.
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Bader HL, Hsu T. Systemic VHL gene functions and the VHL disease. FEBS Lett 2012; 586:1562-9. [PMID: 22673568 DOI: 10.1016/j.febslet.2012.04.032] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 12/19/2022]
Abstract
The von Hippel-Lindau tumor suppressor gene (VHL) is best known as an E3 ubiquitin ligase that negatively regulates the hypoxia inducible factor (HIF). VHL mutations are the genetic defects underlying several human diseases including polycythemia, familial VHL tumor syndrome and sporadic renal cell carcinoma. VHL mutations can lead to cell-autonomous phenotypes in the tumor cells. However, non-tumor cell-autonomous functions of VHL have also been noted. VHL tumor-derived cytokines can promote inflammation and induce mobilization of endothelial progenitor cells. Up-regulation of HIF caused by VHL loss-of-function mutants, including heterozygotes, has been shown to increase the activities of hematopoietic stem cells, endothelial cells and myeloid cells. As such, systemic functions of VHL likely play important roles in the development of VHL disease.
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Affiliation(s)
- Hannah L Bader
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
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Sable CA, Aliyu ZY, Dham N, Nouraie M, Sachdev V, Sidenko S, Miasnikova GY, Polyakova LA, Sergueeva AI, Okhotin DJ, Bushuev V, Remaley AT, Niu X, Castro OL, Gladwin MT, Kato GJ, Prchal JT, Gordeuk VR. Pulmonary artery pressure and iron deficiency in patients with upregulation of hypoxia sensing due to homozygous VHL(R200W) mutation (Chuvash polycythemia). Haematologica 2011; 97:193-200. [PMID: 21993671 DOI: 10.3324/haematol.2011.051839] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Patients with Chuvash polycythemia, (homozygosity for the R200W mutation in the von Hippel Lindau gene (VHL)), have elevated levels of hypoxia inducible factors HIF-1 and HIF-2, often become iron-deficient secondary to phlebotomy, and have elevated estimated pulmonary artery pressure by echocardiography. The objectives of this study were to provide a comprehensive echocardiographic assessment of cardiovascular physiology and to identify clinical, hematologic and cardiovascular risk factors for elevation of tricuspid regurgitation velocity in children and adults with Chuvash polycythemia. DESIGN AND METHODS This cross-sectional observational study of 120 adult and pediatric VHL(R200W) homozygotes and 31 controls at outpatient facilities in Chuvashia, Russian Federation included echocardiography assessment of pulmonary artery pressure (tricuspid regurgitation velocity), cardiac volume, and systolic and diastolic function, as well as hematologic and clinical parameters. We determined the prevalence and risk factors for elevation of tricuspid regurgitation velocity in this population and its relationship to phlebotomy. RESULTS The age-adjusted mean ± SE tricuspid regurgitation velocity was higher in VHL(R200W) homozygotes than controls with normal VHL alleles (2.5±0.03 vs. 2.3±0.05 m/sec, P=0.005). The age-adjusted left ventricular diastolic diameter (4.8±0.05 vs. 4.5±0.09 cm, P=0.005) and left atrial diameter (3.4±0.04 vs. 3.2±0.08 cm, P=0.011) were also greater in the VHL(R200W) homozygotes, consistent with increased blood volume, but the elevation in tricuspid regurgitation velocity persisted after adjustment for these variables. Among VHL(R200W) homozygotes, phlebotomy therapy was associated with lower serum ferritin concentration, and low ferritin independently predicted higher tricuspid regurgitation velocity (standardized beta=0.29; P=0.009). CONCLUSIONS Children and adults with Chuvash polycythemia have higher estimated right ventricular systolic pressure, even after adjustment for echocardiography estimates of blood volume. Lower ferritin concentration, which is associated with phlebotomy, independently predicts higher tricuspid regurgitation velocity (www.clinicaltrials.gov identifier NCT00495638).
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Affiliation(s)
- Craig A Sable
- Division of Cardiology, Children’s National Medical Center, Washington, DC, USA.
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Chuvash polycythemia VHLR200W mutation is associated with down-regulation of hepcidin expression. Blood 2011; 118:5278-82. [PMID: 21876117 DOI: 10.1182/blood-2011-03-345512] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hypoxia is known to reduce the expression of hepcidin, the master regulator of iron metabolism. However, it is not clear whether this response is primarily related to increased erythropoiesis driven by hypoxically stimulated erythropoietin or to a more direct effect of hypoxia on hepcidin expression. The germline loss-of-function VHL(R200W) mutation is common in Chuvashia, Russia, and also occurs elsewhere. VHL(R200W) homozygotes have elevated hypoxia-inducible factor 1α (HIF-1α) and HIF-2α levels, increased red cell mass, propensity to thrombosis, and early mortality. Ninety VHL(R200W) homozygotes and 52 controls with normal VHL alleles from Chuvashia, Russia, were studied under basal circumstances. In univariate analyses, serum hepcidin concentration was correlated positively with serum ferritin concentration and negatively with homozygosity for VHL(R200W). After adjustment for serum erythropoietin and ferritin concentrations by multiple linear regression, the geometric mean (95% confidence interval of mean) hepcidin concentration was 8.1 (6.3-10.5) ng/mL in VHL(R200W) homozygotes versus 26.9 (18.6-38.0) ng/mL in controls (P < .001). In contrast, a significant independent relationship of serum erythropoietin, hemoglobin, or RBC count with hepcidin was not observed. In conclusion, up-regulation of the hypoxic response leads to decreased expression of hepcidin that may be independent of increased erythropoietin levels and increased RBC counts.
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