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Ferens FG, Taber CC, Stuart S, Hubert M, Tarade D, Lee JE, Ohh M. Deficiency in PHD2-mediated hydroxylation of HIF2α underlies Pacak-Zhuang syndrome. Commun Biol 2024; 7:240. [PMID: 38418569 PMCID: PMC10902354 DOI: 10.1038/s42003-024-05904-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 02/09/2024] [Indexed: 03/01/2024] Open
Abstract
Pacak-Zhuang syndrome is caused by mutations in the EPAS1 gene, which encodes for one of the three hypoxia-inducible factor alpha (HIFα) paralogs HIF2α and is associated with defined but varied phenotypic presentations including neuroendocrine tumors and polycythemia. However, the mechanisms underlying the complex genotype-phenotype correlations remain incompletely understood. Here, we devised a quantitative method for determining the dissociation constant (Kd) of the HIF2α peptides containing disease-associated mutations and the catalytic domain of prolyl-hydroxylase (PHD2) using microscale thermophoresis (MST) and showed that neuroendocrine-associated Class 1 HIF2α mutants have distinctly higher Kd than the exclusively polycythemia-associated Class 2 HIF2α mutants. Based on the co-crystal structure of PHD2/HIF2α peptide complex at 1.8 Å resolution, we showed that the Class 1 mutated residues are localized to the critical interface between HIF2α and PHD2, adjacent to the PHD2 active catalytic site, while Class 2 mutated residues are localized to the more flexible region of HIF2α that makes less contact with PHD2. Concordantly, Class 1 mutations were found to significantly increase HIF2α-mediated transcriptional activation in cellulo compared to Class 2 counterparts. These results reveal a structural mechanism in which the strength of the interaction between HIF2α and PHD2 is at the root of the general genotype-phenotype correlations observed in Pacak-Zhuang syndrome.
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Affiliation(s)
- Fraser G Ferens
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Cassandra C Taber
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Sarah Stuart
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Mia Hubert
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Daniel Tarade
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Jeffrey E Lee
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Michael Ohh
- Department of Laboratory Medicine & Pathobiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Biochemistry, Faculty of Medicine, University of Toronto, 661 University Avenue, Toronto, ON, M5G 1M1, Canada.
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2
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Park S, Cho JH, Kim JH, Park M, Park S, Kim SY, Kim SK, Kim K, Park S, Park B, Moon J, Lee G, Kim S, Kim JA, Kim JH. Hypoxia stabilizes SETDB1 to maintain genome stability. Nucleic Acids Res 2023; 51:11178-11196. [PMID: 37850636 PMCID: PMC10639076 DOI: 10.1093/nar/gkad796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 08/17/2023] [Accepted: 09/25/2023] [Indexed: 10/19/2023] Open
Abstract
Von Hippel-Lindau (VHL) is a tumor suppressor that functions as the substrate recognition subunit of the CRL2VHL E3 complex. While substrates of VHL have been identified, its tumor suppressive role remains to be fully understood. For further determination of VHL substrates, we analyzed the physical interactome of VHL and identified the histone H3K9 methyltransferase SETBD1 as a novel target. SETDB1 undergoes oxygen-dependent hydroxylation by prolyl hydroxylase domain proteins and the CRL2VHL complex recognizes hydroxylated SETDB1 for ubiquitin-mediated degradation. Under hypoxic conditions, SETDB1 accumulates by escaping CRL2VHL activity. Loss of SETDB1 in hypoxia compared with that in normoxia escalates the production of transposable element-derived double-stranded RNAs, thereby hyperactivating the immune-inflammatory response. In addition, strong derepression of TEs in hypoxic cells lacking SETDB1 triggers DNA damage-induced death. Our collective results support a molecular mechanism of oxygen-dependent SETDB1 degradation by the CRL2VHL E3 complex and reveal a role of SETDB1 in genome stability under hypoxia.
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Affiliation(s)
- Sungryul Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Jin Hwa Cho
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Jong-Hwan Kim
- Korea Bioinformation Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Mijin Park
- Aging Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Seulki Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Seon-Young Kim
- Korea Bioinformation Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Seon-Kyu Kim
- Aging Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Kidae Kim
- R&D Center, PharmAbcine Inc., Daejeon 34047, Republic of Korea
| | - Sung Goo Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Byoung Chul Park
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
- Critical Diseases Diagnostics Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Jeong Hee Moon
- Core Research Facility & Analysis Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Gaseul Lee
- Core Research Facility & Analysis Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- College of Pharmacy, Chungbuk National University, Cheongju, Chungbuk 28160, Republic of Korea
| | - Sunhong Kim
- Drug Discovery Center, LG Chem Ltd., Seoul 07796, Republic of Korea
| | - Jung-Ae Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Aging Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Jeong-Hoon Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Bioscience, University of Science and Technology, Daejeon 34113, Republic of Korea
- Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon 34134, Republic of Korea
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3
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Figg WD, Fiorini G, Chowdhury R, Nakashima Y, Tumber A, McDonough MA, Schofield CJ. Structural basis for binding of the renal carcinoma target hypoxia-inducible factor 2α to prolyl hydroxylase domain 2. Proteins 2023; 91:1510-1524. [PMID: 37449559 PMCID: PMC10952196 DOI: 10.1002/prot.26541] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/08/2023] [Accepted: 06/08/2023] [Indexed: 07/18/2023]
Abstract
The hypoxia-inducible factor (HIF) prolyl-hydroxylases (human PHD1-3) catalyze prolyl hydroxylation in oxygen-dependent degradation (ODD) domains of HIFα isoforms, modifications that signal for HIFα proteasomal degradation in an oxygen-dependent manner. PHD inhibitors are used for treatment of anemia in kidney disease. Increased erythropoietin (EPO) in patients with familial/idiopathic erythrocytosis and pulmonary hypertension is associated with mutations in EGLN1 (PHD2) and EPAS1 (HIF2α); a drug inhibiting HIF2α activity is used for clear cell renal cell carcinoma (ccRCC) treatment. We report crystal structures of PHD2 complexed with the C-terminal HIF2α-ODD in the presence of its 2-oxoglutarate cosubstrate or N-oxalylglycine inhibitor. Combined with the reported PHD2.HIFα-ODD structures and biochemical studies, the results inform on the different PHD.HIFα-ODD binding modes and the potential effects of clinically observed mutations in HIFα and PHD2 genes. They may help enable new therapeutic avenues, including PHD isoform-selective inhibitors and sequestration of HIF2α by the PHDs for ccRCC treatment.
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Affiliation(s)
- William D. Figg
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
| | - Giorgia Fiorini
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
| | - Rasheduzzaman Chowdhury
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
| | - Yu Nakashima
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
- Institute of Natural Medicine, University of ToyamaToyamaJapan
| | - Anthony Tumber
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
| | - Michael A. McDonough
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
| | - Christopher J. Schofield
- Chemistry Research Laboratory, Department of Chemistry and the Ineos OxfordInstitute for Antimicrobial Research, University of OxfordOxfordUK
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Mendoza SV, Genetos DC, Yellowley CE. Hypoxia-Inducible Factor-2α Signaling in the Skeletal System. JBMR Plus 2023; 7:e10733. [PMID: 37065626 PMCID: PMC10097641 DOI: 10.1002/jbm4.10733] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/13/2023] Open
Abstract
Hypoxia-inducible factors (HIFs) are oxygen-dependent heterodimeric transcription factors that mediate molecular responses to reductions in cellular oxygen (hypoxia). HIF signaling involves stable HIF-β subunits and labile, oxygen-sensitive HIF-α subunits. Under hypoxic conditions, the HIF-α subunit is stabilized, complexes with nucleus-confined HIF-β subunit, and transcriptionally regulates hypoxia-adaptive genes. Transcriptional responses to hypoxia include altered energy metabolism, angiogenesis, erythropoiesis, and cell fate. Three isoforms of HIF-α-HIF-1α, HIF-2α, and HIF-3α-are found in diverse cell types. HIF-1α and HIF-2α serve as transcriptional activators, whereas HIF-3α restricts HIF-1α and HIF-2α. The structure and isoform-specific functions of HIF-1α in mediating molecular responses to hypoxia are well established across a wide range of cell and tissue types. The contributions of HIF-2α to hypoxic adaptation are often unconsidered if not outrightly attributed to HIF-1α. This review establishes what is currently known about the diverse roles of HIF-2α in mediating the hypoxic response in skeletal tissues, with specific focus on development and maintenance of skeletal fitness. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Sarah V Mendoza
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of California, DavisDavisCAUSA
| | - Damian C Genetos
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of California, DavisDavisCAUSA
| | - Clare E Yellowley
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary MedicineUniversity of California, DavisDavisCAUSA
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5
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Wang H, Tang C, Dang ZH, Yong A, Liu L, Wang S, Zhao M. Clinicopathological characteristics of high-altitude polycythemia-related kidney disease in Tibetan inhabitants. Kidney Int 2022; 102:196-206. [PMID: 35513124 DOI: 10.1016/j.kint.2022.03.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/04/2022] [Accepted: 03/29/2022] [Indexed: 11/27/2022]
Abstract
High-altitude polycythemia (HAPC) is a clinical syndrome that occurs in native inhabitants or long-term residents living at altitude. The kidney is one of the most affected organs. However, the clinical and kidney histopathological profiles of HAPC-related kidney disease have rarely been reported. Here, we report kidney biopsy-based clinicopathological study on this disease. HAPC was defined as excessive erythrocytosis [females, hemoglobin 190 g/L or more; males, 210 g/L or more] in patients living above an altitude of 2500 m for more than ten years. A total of 416 Tibetan patients underwent kidney biopsy between January 1, 2016, and November 31, 2020. Of these patients 17 met the diagnostic criteria for HAPC-related kidney disease. Clinically, these patients had a median urinary protein level of 2.5 g/24-hour (range 1.81-6.85). Twelve patients had hyperuricemia, nine had hypertension, and three had kidney insufficiency. On histopathology, glomerular hypertrophy, glomerular basement membrane thickening, podocyte foot process effacement, segmental glomerulosclerosis and global glomerulosclerosis were the main features. Extraglomerular arterial/arteriolar lesions were common, presenting as intimal fibrosis, hyalinosis and endothelial cell swelling/subintimal edema. Expansion of the arterial/arteriolar medial wall area characterized by smooth muscle cell proliferation was clearly observed, potentially indicating vascular remodeling. Hypoxia-inducible factor 2α was expressed in the kidney tissues of these patients. Thus, the pathological changes of HAPC-related kidney disease encompassed both glomerular and extraglomerular vascular lesions, suggesting a key role of both chronic hypoxia itself and secondary hemodynamic changes in the pathogenesis of this disease.
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Affiliation(s)
- Hui Wang
- Renal Division, Department of Medicine, Peking University First Hospital; Renal Pathological Center, Institute of Nephrology, Peking University; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China; Beijing 100034, P.R. China; Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing 100034, P.R. China
| | - Chen Tang
- Renal Division, Department of Medicine, Peking University First Hospital; Renal Pathological Center, Institute of Nephrology, Peking University; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China; Beijing 100034, P.R. China
| | - Zong-Hui Dang
- The People's Hospital of Tibet Autonomous region, Lhasa, Tibet, P.R. China
| | - A Yong
- The People's Hospital of Tibet Autonomous region, Lhasa, Tibet, P.R. China
| | - Lijun Liu
- Renal Division, Department of Medicine, Peking University First Hospital; Renal Pathological Center, Institute of Nephrology, Peking University; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China; Beijing 100034, P.R. China.
| | - Suxia Wang
- Renal Division, Department of Medicine, Peking University First Hospital; Renal Pathological Center, Institute of Nephrology, Peking University; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China; Beijing 100034, P.R. China; Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing 100034, P.R. China.
| | - Minghui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital; Renal Pathological Center, Institute of Nephrology, Peking University; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China; Beijing 100034, P.R. China
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6
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Mima A. Hypoxia-inducible factor-prolyl hydroxylase inhibitors for renal anemia in chronic kidney disease: Advantages and disadvantages. Eur J Pharmacol 2021; 912:174583. [PMID: 34678238 DOI: 10.1016/j.ejphar.2021.174583] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 12/17/2022]
Abstract
Anemia is a common feature and complication of chronic kidney disease (CKD). Erythropoiesis-stimulating agents (ESAs) and recombinant human erythropoietin have been used widely in renal anemia treatment. Recently, hypoxia-inducible factor-prolyl hydroxylase domain inhibitors (HIF-PHIs) that may improve the treatment of renal anemia patients were launched. Previous studies indicated that HIF-PHIs may decrease hepcidin levels and modulate iron metabolism, thereby increasing total iron-binding capacity and reducing the need for iron supplementation. Furthermore, HIF-PHIs can reduce inflammation and oxidative stress in CKD. Recombinant erythropoietin has become a routine treatment for patients with CKD and end-stage renal disease with relatively few adverse effects. However, higher doses of recombinant erythropoietin have been demonstrated to be an independent predictor of mortality in patients under hemodialysis. Phase III clinical trials of HIF-PHIs in patients with anemia and dialysis-dependent CKD have shown their efficacy and safety in both non-dialysis and dialysis CKD patients. However, HIFα binds to specific hypoxia-response elements in the vascular endothelial growth factor or retinoic acid-related orphan receptor gamma t (RORγt) promoter, which may be involved in the progression of cancer, psoriasis, and rheumatoid arthritis. In this paper, we have summarized the mechanism, clinical application, and clinical trials of HIF-PHIs in the treatment of renal anemia and aimed to provide an overview of the new drugs in clinical practice, as well as reconsider the advantages and disadvantages of HIF-PHIs and ESAs. Presently, there are not enough clinical studies examining the effects of long-term administration of HIF-PHIs. Therefore, further studies will be needed.
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Affiliation(s)
- Akira Mima
- Department of Nephrology, Osaka Medical and Pharmaceutical University, Osaka, Japan.
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Kristan A, Debeljak N, Kunej T. Integration and Visualization of Regulatory Elements and Variations of the EPAS1 Gene in Human. Genes (Basel) 2021; 12:genes12111793. [PMID: 34828399 PMCID: PMC8620933 DOI: 10.3390/genes12111793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 01/15/2023] Open
Abstract
Endothelial PAS domain-containing protein 1 (EPAS1), also HIF2α, is an alpha subunit of hypoxia-inducible transcription factor (HIF), which mediates cellular and systemic response to hypoxia. EPAS1 has an important role in the transcription of many hypoxia-responsive genes, however, it has been less researched than HIF1α. The aim of this study was to integrate an increasing number of data on EPAS1 into a map of diverse OMICs elements. Publications, databases, and bioinformatics tools were examined, including Ensembl, MethPrimer, STRING, miRTarBase, COSMIC, and LOVD. The EPAS1 expression, stability, and activity are tightly regulated on several OMICs levels to maintain complex oxygen homeostasis. In the integrative EPAS1 map we included: 31 promoter-binding proteins, 13 interacting miRNAs and one lncRNA, and 16 post-translational modifications regulating EPAS1 protein abundance. EPAS1 has been associated with various cancer types and other diseases. The development of neuroendocrine tumors and erythrocytosis was shown to be associated with 11 somatic and 20 germline variants. The integrative map also includes 12 EPAS1 target genes and 27 interacting proteins. The study introduced the first integrative map of diverse genomics, transcriptomics, proteomics, regulomics, and interactomics data associated with EPAS1, to enable a better understanding of EPAS1 activity and regulation and support future research.
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Affiliation(s)
- Aleša Kristan
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.K.); (N.D.)
| | - Nataša Debeljak
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia; (A.K.); (N.D.)
| | - Tanja Kunej
- Department for Animal Science, Biotechnical Faculty, University of Ljubljana, 1230 Domžale, Slovenia
- Correspondence:
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8
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Kristan A, Pajič T, Maver A, Režen T, Kunej T, Količ R, Vuga A, Fink M, Žula Š, Podgornik H, Anžej Doma S, Preložnik Zupan I, Rozman D, Debeljak N. Identification of Variants Associated With Rare Hematological Disorder Erythrocytosis Using Targeted Next-Generation Sequencing Analysis. Front Genet 2021; 12:689868. [PMID: 34349782 PMCID: PMC8327209 DOI: 10.3389/fgene.2021.689868] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/16/2021] [Indexed: 12/28/2022] Open
Abstract
An erythrocytosis is present when the red blood cell mass is increased, demonstrated as elevated hemoglobin and hematocrit in the laboratory evaluation. Congenital predispositions for erythrocytosis are rare, with germline variants in several genes involved in oxygen sensing (VHL, EGLN1, and EPAS1), signaling for hematopoietic cell maturation (EPOR and EPO), and oxygen transfer (HBB, HBA1, HBA2, and BPGM) that were already associated with the eight congenital types (ECYT1–8). Screening for variants in known congenital erythrocytosis genes with classical sequencing approach gives a correct diagnosis for only up to one-third of the patients. The genetic background of erythrocytosis is more heterogeneous, and additional genes involved in erythropoiesis and iron metabolism could have a putative effect on the development of erythrocytosis. This study aimed to detect variants in patients with yet unexplained erythrocytosis using the next-generation sequencing (NGS) approach, targeting genes associated with erythrocytosis and increased iron uptake and implementing the diagnostics of congenital erythrocytosis in Slovenia. Selected 25 patients with high hemoglobin, high hematocrit, and no acquired causes were screened for variants in the 39 candidate genes. We identified one pathogenic variant in EPAS1 gene and three novel variants with yet unknown significance in genes EPAS1, JAK2, and SH2B3. Interestingly, a high proportion of patients were heterozygous carriers for two variants in HFE gene, otherwise pathogenic for the condition of iron overload. The association between the HFE variants and the development of erythrocytosis is not clearly understood. With a targeted NGS approach, we determined an actual genetic cause for the erythrocytosis in one patient and contributed to better management of the disease for the patient and his family. The effect of variants of unknown significance on the enhanced production of red blood cells needs to be further explored with functional analysis. This study is of great significance for the improvement of diagnosis of Slovenian patients with unexplained erythrocytosis and future research on the etiology of this rare hematological disorder.
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Affiliation(s)
- Aleša Kristan
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tadej Pajič
- Department of Hematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Clinical Biochemistry, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Aleš Maver
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Tadeja Režen
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tanja Kunej
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rok Količ
- Kemomed Research and Development, Kemomed Ltd., Ljubljana, Slovenia
| | - Andrej Vuga
- Kemomed Research and Development, Kemomed Ltd., Ljubljana, Slovenia
| | - Martina Fink
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Department of Hematology, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Špela Žula
- Department of Hematology, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Helena Podgornik
- Department of Hematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Saša Anžej Doma
- Department of Hematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Irena Preložnik Zupan
- Department of Hematology, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Damjana Rozman
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Nataša Debeljak
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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HIF2A gain-of-function mutation modulates the stiffness of smooth muscle cells and compromises vascular mechanics. iScience 2021; 24:102246. [PMID: 33796838 PMCID: PMC7995528 DOI: 10.1016/j.isci.2021.102246] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/26/2020] [Accepted: 02/25/2021] [Indexed: 02/08/2023] Open
Abstract
Heterozygous gain-of-function (GOF) mutations of hypoxia-inducible factor 2α (HIF2A), a key hypoxia-sensing regulator, are associated with erythrocytosis, thrombosis, and vascular complications that account for morbidity and mortality of patients. We demonstrated that the vascular pathology of HIF2A GOF mutations is independent of erythrocytosis. We generated HIF2A GOF-induced pluripotent stem cells (iPSCs) and differentiated them into endothelial cells (ECs) and smooth muscle cells (SMCs). Unexpectedly, HIF2A-SMCs, but not HIF2A-ECs, were phenotypically aberrant, more contractile, stiffer, and overexpressed endothelin 1 (EDN1), myosin heavy chain, elastin, and fibrillin. EDN1 inhibition and knockdown of EDN1-receptors both reduced HIF2-SMC stiffness. Hif2A GOF heterozygous mice displayed pulmonary hypertension, had SMCs with more disorganized stress fibers and higher stiffness in their pulmonary arterial smooth muscle cells, and had more deformable pulmonary arteries compared with wild-type mice. Our findings suggest that targeting these vascular aberrations could benefit patients with HIF2A GOF and conditions of augmented hypoxia signaling. HIF2-SMCs are stiffer than WT-SMCs and differ in contractile SMC marker expression HIF2-SMCs and WT-SMCs differ in EDN1 production and ECM composition HIF- 2α induces EDN1; EDNI subsequently induces SMC stiffening Hif2A GOF mouse arterial SMCs have more disorganized stress fibers and are stiffer
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High-altitude deer mouse hypoxia-inducible factor-2α shows defective interaction with CREB-binding protein. J Biol Chem 2021; 296:100461. [PMID: 33639161 PMCID: PMC8024697 DOI: 10.1016/j.jbc.2021.100461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/16/2021] [Accepted: 02/23/2021] [Indexed: 12/26/2022] Open
Abstract
Numerous mammalian species have adapted to the chronic hypoxia of high altitude. Recent genomic studies have identified evidence for natural selection of genes and associated genetic changes in these species. A major gap in our knowledge is an understanding of the functional significance, if any, of these changes. Deer mice (Peromyscus maniculatus) live at both low and high altitudes in North America, providing an opportunity to identify functionally important genetic changes. High-altitude deer mice show evidence of natural selection on the Epas1 gene, which encodes for hypoxia-inducible factor-2α (Hif-2α), a central transcription factor of the hypoxia-inducible factor pathway. An SNP encoding for a T755M change in the Hif-2α protein is highly enriched in high-altitude deer mice, but its functional significance is unknown. Here, using coimmunoprecipitation and transcriptional activity assays, we show that the T755M mutation produces a defect in the interaction of Hif-2α with the transcriptional coactivator CREB-binding protein. This results in a loss of function because of decreased transcriptional activity. Intriguingly, the effect of this mutation depends on the amino acid context. Interchanges between methionine and threonine at the corresponding position in house mouse (Mus musculus) Hif-2α are without effects on CREB-binding protein binding. Furthermore, transfer of a set of deer mouse–specific Hif-2α amino acids to house mouse Hif-2α is sufficient to confer sensitivity of house mouse Hif-2α to the T755M substitution. These findings provide insight into high-altitude adaptation in deer mice and evolution at the Epas1 locus.
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The Role of Butyrylcholinesterase and Iron in the Regulation of Cholinergic Network and Cognitive Dysfunction in Alzheimer's Disease Pathogenesis. Int J Mol Sci 2021; 22:ijms22042033. [PMID: 33670778 PMCID: PMC7922581 DOI: 10.3390/ijms22042033] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), the most common form of dementia in elderly individuals, is marked by progressive neuron loss. Despite more than 100 years of research on AD, there is still no treatment to cure or prevent the disease. High levels of amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs) in the brain are neuropathological hallmarks of AD. However, based on postmortem analyses, up to 44% of individuals have been shown to have high Aβ deposits with no clinical signs, due to having a “cognitive reserve”. The biochemical mechanism explaining the prevention of cognitive impairment in the presence of Aβ plaques is still unknown. It seems that in addition to protein aggregation, neuroinflammatory changes associated with aging are present in AD brains that are correlated with a higher level of brain iron and oxidative stress. It has been shown that iron accumulates around amyloid plaques in AD mouse models and postmortem brain tissues of AD patients. Iron is required for essential brain functions, including oxidative metabolism, myelination, and neurotransmitter synthesis. However, an imbalance in brain iron homeostasis caused by aging underlies many neurodegenerative diseases. It has been proposed that high iron levels trigger an avalanche of events that push the progress of the disease, accelerating cognitive decline. Patients with increased amyloid plaques and iron are highly likely to develop dementia. Our observations indicate that the butyrylcholinesterase (BChE) level seems to be iron-dependent, and reports show that BChE produced by reactive astrocytes can make cognitive functions worse by accelerating the decay of acetylcholine in aging brains. Why, even when there is a genetic risk, do symptoms of the disease appear after many years? Here, we discuss the relationship between genetic factors, age-dependent iron tissue accumulation, and inflammation, focusing on AD.
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Roles of HIF and 2-Oxoglutarate-Dependent Dioxygenases in Controlling Gene Expression in Hypoxia. Cancers (Basel) 2021; 13:cancers13020350. [PMID: 33477877 PMCID: PMC7832865 DOI: 10.3390/cancers13020350] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Hypoxia—reduction in oxygen availability—plays key roles in both physiological and pathological processes. Given the importance of oxygen for cell and organism viability, mechanisms to sense and respond to hypoxia are in place. A variety of enzymes utilise molecular oxygen, but of particular importance to oxygen sensing are the 2-oxoglutarate (2-OG) dependent dioxygenases (2-OGDs). Of these, Prolyl-hydroxylases have long been recognised to control the levels and function of Hypoxia Inducible Factor (HIF), a master transcriptional regulator in hypoxia, via their hydroxylase activity. However, recent studies are revealing that such dioxygenases are involved in almost all aspects of gene regulation, including chromatin organisation, transcription and translation. Abstract Hypoxia—reduction in oxygen availability—plays key roles in both physiological and pathological processes. Given the importance of oxygen for cell and organism viability, mechanisms to sense and respond to hypoxia are in place. A variety of enzymes utilise molecular oxygen, but of particular importance to oxygen sensing are the 2-oxoglutarate (2-OG) dependent dioxygenases (2-OGDs). Of these, Prolyl-hydroxylases have long been recognised to control the levels and function of Hypoxia Inducible Factor (HIF), a master transcriptional regulator in hypoxia, via their hydroxylase activity. However, recent studies are revealing that dioxygenases are involved in almost all aspects of gene regulation, including chromatin organisation, transcription and translation. We highlight the relevance of HIF and 2-OGDs in the control of gene expression in response to hypoxia and their relevance to human biology and health.
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Pamenter ME, Hall JE, Tanabe Y, Simonson TS. Cross-Species Insights Into Genomic Adaptations to Hypoxia. Front Genet 2020; 11:743. [PMID: 32849780 PMCID: PMC7387696 DOI: 10.3389/fgene.2020.00743] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
Over millions of years, vertebrate species populated vast environments spanning the globe. Among the most challenging habitats encountered were those with limited availability of oxygen, yet many animal and human populations inhabit and perform life cycle functions and/or daily activities in varying degrees of hypoxia today. Of particular interest are species that inhabit high-altitude niches, which experience chronic hypobaric hypoxia throughout their lives. Physiological and molecular aspects of adaptation to hypoxia have long been the focus of high-altitude populations and, within the past decade, genomic information has become increasingly accessible. These data provide an opportunity to search for common genetic signatures of selection across uniquely informative populations and thereby augment our understanding of the mechanisms underlying adaptations to hypoxia. In this review, we synthesize the available genomic findings across hypoxia-tolerant species to provide a comprehensive view of putatively hypoxia-adaptive genes and pathways. In many cases, adaptive signatures across species converge on the same genetic pathways or on genes themselves [i.e., the hypoxia inducible factor (HIF) pathway). However, specific variants thought to underlie function are distinct between species and populations, and, in most cases, the precise functional role of these genomic differences remains unknown. Efforts to standardize these findings and explore relationships between genotype and phenotype will provide important clues into the evolutionary and mechanistic bases of physiological adaptations to environmental hypoxia.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- Ottawa Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - James E. Hall
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Yuuka Tanabe
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
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14
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Kristan A, Debeljak N, Kunej T. Genetic variability of hypoxia-inducible factor alpha (HIFA) genes in familial erythrocytosis: Analysis of the literature and genome databases. Eur J Haematol 2019; 103:287-299. [PMID: 31376207 DOI: 10.1111/ejh.13304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/21/2019] [Accepted: 07/25/2019] [Indexed: 12/11/2022]
Abstract
Familial erythrocytosis (FE) is a congenital disorder, defined by elevated red blood cell number, hemoglobin, and hematocrit. Among eight types of FE, type 4 is caused by variants in the EPAS1 gene. Two other hypoxia-inducible factor alpha (HIFA) subunits, HIF1A and HIF3A, have not yet been associated with medical history of FE, but have potential role in the development of erythrocytosis. To improve diagnosis, it is crucial to identify new variants in genes involved in erythrocyte production. Published literature and data from genome browsers were used to obtain HIFA sequence variants associated with erythrocytosis and to locate them on protein sequence and regulatory sites. We retrieved 24 variants from the literature: 2 in HIF1A, 20 in EPAS1 and 2 in HIF3A gene. Sixteen out of 20 variants in the EPAS1 gene are positioned in a conserved region of 13 amino acids within exon 12, next to regulatory post-translational modification and binding sites, suggesting that EPAS1 has an important role in erythropoiesis. The role of HIF1A and HIF3A in the development of erythrocytosis should be further investigated.
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Affiliation(s)
- Aleša Kristan
- Medical Centre for Molecular Biology, Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Ljubljana, Slovenia
| | - Nataša Debeljak
- Medical Centre for Molecular Biology, Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Ljubljana, Slovenia
| | - Tanja Kunej
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
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15
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Tarade D, Robinson CM, Lee JE, Ohh M. HIF-2α-pVHL complex reveals broad genotype-phenotype correlations in HIF-2α-driven disease. Nat Commun 2018; 9:3359. [PMID: 30135421 PMCID: PMC6105673 DOI: 10.1038/s41467-018-05554-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/11/2018] [Indexed: 12/30/2022] Open
Abstract
It is definitively established that mutations in transcription factor HIF-2α are causative of both neuroendocrine tumors (class 1 disease) and polycythemia (class 2 disease). However, the molecular mechanism that underlies this emergent genotype–phenotype relationship has remained unclear. Here, we report the structure of HIF-2α peptide bound to pVHL-elongin B-elongin C (VBC) heterotrimeric complex, which shows topographical demarcation of class 1 and 2 mutations affecting residues predicted, and demonstrated via biophysical analyses, to differentially impact HIF-2α-pVHL interaction interface stability. Concordantly, biochemical experiments showed that class 1 mutations disrupt pVHL affinity to HIF-2α more adversely than class 2 mutations directly or indirectly via impeding PHD2-mediated hydroxylation. These findings suggest that neuroendocrine tumor pathogenesis requires a higher HIF-2α dose than polycythemia, which requires only a mild increase in HIF-2α activity. These biophysical data reveal a structural basis that underlies, and can be used to predict de novo, broad genotype-phenotype correlations in HIF-2α-driven disease. Hypoxia inducible factor (HIF)-2α transcription factor is mutated in polycythemia and various neuroendocrine tumors. Here the authors present the crystal structure of a HIF-2α peptide bound to the pVHL-elongin B-elongin C (VBC) heterotrimeric complex and propose a classification scheme for HIF-2α mutations that helps to predict disease phenotype outcome.
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Affiliation(s)
- Daniel Tarade
- Department of Laboratory Medicine & Pathobiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Claire M Robinson
- Department of Laboratory Medicine & Pathobiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Jeffrey E Lee
- Department of Laboratory Medicine & Pathobiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Michael Ohh
- Department of Laboratory Medicine & Pathobiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. .,Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON, M5G 1M1, Canada.
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16
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Kaplan JM, Sharma N, Dikdan S. Hypoxia-Inducible Factor and Its Role in the Management of Anemia in Chronic Kidney Disease. Int J Mol Sci 2018; 19:ijms19020389. [PMID: 29382128 PMCID: PMC5855611 DOI: 10.3390/ijms19020389] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 12/25/2022] Open
Abstract
Hypoxia-inducible factor (HIF) plays a crucial role in the response to hypoxia at the cellular, tissue, and organism level. New agents under development to pharmacologically manipulate HIF may provide new and exciting possibilities in the treatment of anemia of chronic kidney disease (CKD) as well as in multiple other disease states involving ischemia-reperfusion injury. This article provides an overview of recent studies describing current standards of care for patients with anemia in CKD and associated clinical issues, and those supporting the clinical potential for targeting HIF stabilization with HIF prolyl-hydroxylase inhibitors (HIF-PHI) in these patients. Additionally, articles reporting the clinical potential for HIF-PHIs in 'other' putative therapeutic areas, the tissue and intracellular distribution of HIF- and prolyl-hydroxylase domain (PHD) isoforms, and HIF isoforms targeted by the different PHDs, were identified. There is increasing uncertainty regarding the optimal treatment for anemia of CKD with poorer outcomes associated with treatment to higher hemoglobin targets, and the increasing use of iron and consequent risk of iron imbalance. Attainment and maintenance of more physiologic erythropoietin levels associated with HIF stabilization may improve the management of patients resistant to treatment with erythropoiesis-stimulating agents and improve outcomes at higher hemoglobin targets.
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Affiliation(s)
- Joshua M Kaplan
- Division of Nephrology and Hypertension, Rutgers-New Jersey Medical School, University Hospital, 185 South Orange Avenue, I512, Newark, NJ 07103, USA.
| | - Neeraj Sharma
- Division of Nephrology and Hypertension, Rutgers-New Jersey Medical School, University Hospital, 185 South Orange Avenue, I512, Newark, NJ 07103, USA.
| | - Sean Dikdan
- Division of Nephrology and Hypertension, Rutgers-New Jersey Medical School, University Hospital, 185 South Orange Avenue, I512, Newark, NJ 07103, USA.
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Därr R, Nambuba J, Del Rivero J, Janssen I, Merino M, Todorovic M, Balint B, Jochmanova I, Prchal JT, Lechan RM, Tischler AS, Popovic V, Miljic D, Adams KT, Prall FR, Ling A, Golomb MR, Ferguson M, Nilubol N, Chen CC, Chew E, Taïeb D, Stratakis CA, Fojo T, Yang C, Kebebew E, Zhuang Z, Pacak K. Novel insights into the polycythemia-paraganglioma-somatostatinoma syndrome. Endocr Relat Cancer 2016; 23:899-908. [PMID: 27679736 PMCID: PMC5096964 DOI: 10.1530/erc-16-0231] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 09/27/2016] [Indexed: 12/14/2022]
Abstract
Worldwide, the syndromes of paraganglioma (PGL), somatostatinoma (SOM) and early childhood polycythemia are described in only a few patients with somatic mutations in the hypoxia-inducible factor 2 alpha (HIF2A). This study provides detailed information about the clinical aspects and course of 7 patients with this syndrome and brings into perspective these experiences with the pertinent literature. Six females and one male presented at a median age of 28 years (range 11-46). Two were found to have HIF2A somatic mosaicism. No relatives were affected. All patients were diagnosed with polycythemia before age 8 and before PGL/SOM developed. PGLs were found at a median age of 17 years (range 8-38) and SOMs at 29 years (range 22-38). PGLs were multiple, recurrent and metastatic in 100, 100 and 29% of all cases, and SOMs in 40, 40 and 60%, respectively. All PGLs were primarily norepinephrine-producing. All patients had abnormal ophthalmologic findings and those with SOMs had gallbladder disease. Computed tomography (CT) and magnetic resonance imaging revealed cystic lesions at multiple sites and hemangiomas in 4 patients (57%), previously thought to be pathognomonic for von Hippel-Lindau disease. The most accurate radiopharmaceutical to detect PGL appeared to be [18F]-fluorodihydroxyphenylalanine ([18F]-FDOPA). Therefore, [18F]-FDOPA PET/CT, not [68Ga]-(DOTA)-[Tyr3]-octreotate ([68Ga]-DOTATATE) PET/CT is recommended for tumor localization and aftercare in this syndrome. The long-term prognosis of the syndrome is unknown. However, to date no deaths occurred after 6 years follow-up. Physicians should be aware of this unique syndrome and its diagnostic and therapeutic challenges.
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Affiliation(s)
- Roland Därr
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Joan Nambuba
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Jaydira Del Rivero
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Ingo Janssen
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Maria Merino
- Laboratory of PathologyNational Institutes of Health, Bethesda, Maryland, USA
| | - Milena Todorovic
- Institute of HematologyClinical Center of Serbia and Medical Faculty University of Belgrade, Belgrade, Serbia
| | - Bela Balint
- Institute of Transfusiology and Hemobiology of Military Medical Academy and Institute for Medical ResearchUniversity of Belgrade, Belgrade, Serbia
| | - Ivana Jochmanova
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
- 1st Department of Internal MedicineFaculty of Medicine, Pavol Jozef Safarik University in Kosice, Kosice, Slovakia
| | - Josef T Prchal
- Division of HematologyUniversity of Utah, Salt Lake City, Utah, USA
| | - Ronald M Lechan
- Tupper Research Institute and Department of MedicineDivision of Endocrinology, Diabetes and Metabolism, Tufts Medical Center, Boston, Massachusetts, USA
| | - Arthur S Tischler
- Department of Pathology and Laboratory MedicineTufts Medical Center, Boston, Massachusetts, USA
| | - Vera Popovic
- Institute of EndocrinologyClinical Center of Serbia, Medical Faculty, University Belgrade, Belgrade, Serbia
| | - Dragana Miljic
- Institute of EndocrinologyClinical Center of Serbia, Medical Faculty, University Belgrade, Belgrade, Serbia
| | - Karen T Adams
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - F Ryan Prall
- Department of OphthalmologyEugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Alexander Ling
- Department of Radiology and Imaging SciencesClinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Meredith R Golomb
- Division of Child NeurologyDepartment of Neurology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michael Ferguson
- Riley Hospital for Children at Indiana University HealthIndianapolis, Indiana, USA
| | - Naris Nilubol
- Endocrine Oncology BranchNational Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Clara C Chen
- Division of Nuclear MedicineDepartment of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Emily Chew
- Division of Epidemiology and Clinical ApplicationsNational Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - David Taïeb
- Department of Nuclear MedicineLa Timone University Hospital & CERIMED & Inserm UMR1068 Marseille Cancerology Research Center, Institut Paoli-Calmettes, Aix-Marseille University, Marseille, France
| | - Constantine A Stratakis
- Division of Intramural ResearchEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Tito Fojo
- Medical Oncology BranchNational Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chunzhang Yang
- Neuro-Oncology BranchCenter for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Electron Kebebew
- Endocrine Oncology BranchNational Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Zhengping Zhuang
- Neuro-Oncology BranchCenter for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Karel Pacak
- Section on Medical NeuroendocrinologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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Yousaf F, Spinowitz B. Hypoxia-Inducible Factor Stabilizers: a New Avenue for Reducing BP While Helping Hemoglobin? Curr Hypertens Rep 2016; 18:23. [DOI: 10.1007/s11906-016-0629-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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19
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Heir P, Srikumar T, Bikopoulos G, Bunda S, Poon BP, Lee JE, Raught B, Ohh M. Oxygen-dependent Regulation of Erythropoietin Receptor Turnover and Signaling. J Biol Chem 2016; 291:7357-72. [PMID: 26846855 DOI: 10.1074/jbc.m115.694562] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Indexed: 01/29/2023] Open
Abstract
von Hippel-Lindau (VHL) disease is a rare familial cancer predisposition syndrome caused by a loss or mutation in a single gene,VHL, but it exhibits a wide phenotypic variability that can be categorized into distinct subtypes. The phenotypic variability has been largely argued to be attributable to the extent of deregulation of the α subunit of hypoxia-inducible factor α, a well established target of VHL E3 ubiquitin ligase, ECV (Elongins/Cul2/VHL). Here, we show that erythropoietin receptor (EPOR) is hydroxylated on proline 419 and 426 via prolyl hydroxylase 3. EPOR hydroxylation is required for binding to the β domain of VHL and polyubiquitylation via ECV, leading to increased EPOR turnover. In addition, several type-specific VHL disease-causing mutants, including those that have retained proper binding and regulation of hypoxia-inducible factor α, showed a severe defect in binding prolyl hydroxylated EPOR peptides. These results identify EPOR as the secondbona fidehydroxylation-dependent substrate of VHL that potentially influences oxygen homeostasis and contributes to the complex genotype-phenotype correlation in VHL disease.
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Affiliation(s)
- Pardeep Heir
- From the Departments of Laboratory Medicine and Pathobiology and
| | - Tharan Srikumar
- the Princess Margaret Cancer Centre, Toronto, Ontario M5G 1L7, Canada
| | | | - Severa Bunda
- From the Departments of Laboratory Medicine and Pathobiology and
| | - Betty P Poon
- From the Departments of Laboratory Medicine and Pathobiology and Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8 and
| | - Jeffrey E Lee
- From the Departments of Laboratory Medicine and Pathobiology and
| | - Brian Raught
- the Princess Margaret Cancer Centre, Toronto, Ontario M5G 1L7, Canada
| | - Michael Ohh
- From the Departments of Laboratory Medicine and Pathobiology and Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8 and
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20
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Su J, Li Z, Cui S, Ji L, Geng H, Chai K, Ma X, Bai Z, Yang Y, Wuren T, Ge RL, Rondina MT. The Local HIF-2α/EPO Pathway in the Bone Marrow is Associated with Excessive Erythrocytosis and the Increase in Bone Marrow Microvessel Density in Chronic Mountain Sickness. High Alt Med Biol 2015; 16:318-30. [PMID: 26625252 DOI: 10.1089/ham.2015.0015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
AIM Chronic mountain sickness (CMS) is characterized by excessive erythrocytosis, and angiogenesis may be involved in the pathogenesis of this disease. The bone marrow niche is the primary site of erythropoiesis and angiogenesis. This study was aimed at investigating the associations of the levels of hypoxia-inducible factors (HIFs), erythropoietin (EPO), and erythropoietin receptor (EPOR), as well as microvessel density (MVD) in the bone marrow with CMS. RESULTS A total of 34 patients with CMS and 30 control subjects residing in areas at altitudes of 3000-4500 m were recruited for this study. The mRNA and protein expression of HIF-2α and EPO in the bone marrow cells was significantly higher in the CMS patients than in the controls. Moreover, changes in HIF-2α expression in CMS patients were significantly correlated with EPO and hemoglobin levels. In contrast, the expression of mRNA and protein expression of HIF-1α and EPOR did not differ significantly between the CMS and control patients. Increased MVD was observed in the bone marrow of the patients with CMS and it was significantly correlated with hemoglobin. CONCLUSIONS Bone marrow cells of CMS patients may show enhanced activity of the HIF-2α/EPO pathway, and EPO may regulate the erythropoiesis and vasculogenesis through autocrine or/and paracrine mechanisms in the bone marrow niche. The increased MVD in the bone marrow of CMS patients appears to be involved in the pathogenesis of this disease.
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Affiliation(s)
- Juan Su
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Zhanquan Li
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Sen Cui
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Linhua Ji
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Hui Geng
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Kexia Chai
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Xiaojing Ma
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China .,2 Department of Hematology, Qinghai University Affiliated Hospital , Xining, China
| | - Zhenzhong Bai
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China
| | - Yingzhong Yang
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China
| | - Tana Wuren
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China
| | - Ri-Li Ge
- 1 Research Center for High Altitude Medicine, Qinghai University , Xining, China
| | - Matthew T Rondina
- 3 Division of General Internal Medicine and University Healthcare Thrombosis Service, Department of Internal Medicine, University of Utah Health Sciences Center , Salt Lake City, Utah
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Abstract
Humans have adapted to the chronic hypoxia of high altitude in several locations, and recent genome-wide studies have indicated a genetic basis. In some populations, genetic signatures have been identified in the hypoxia-inducible factor (HIF) pathway, which orchestrates the transcriptional response to hypoxia. In Tibetans, they have been found in the HIF2A (EPAS1) gene, which encodes for HIF-2α, and the prolyl hydroxylase domain protein 2 (PHD2, also known as EGLN1) gene, which encodes for one of its key regulators, PHD2. High-altitude adaptation may be due to multiple genes that act in concert with one another. Unraveling their mechanism of action can offer new therapeutic approaches toward treating common human diseases characterized by chronic hypoxia.
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Affiliation(s)
- Abigail W Bigham
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Frank S Lee
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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22
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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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23
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Van Roey K, Uyar B, Weatheritt RJ, Dinkel H, Seiler M, Budd A, Gibson TJ, Davey NE. Short Linear Motifs: Ubiquitous and Functionally Diverse Protein Interaction Modules Directing Cell Regulation. Chem Rev 2014; 114:6733-78. [DOI: 10.1021/cr400585q] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kim Van Roey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Robert J. Weatheritt
- MRC
Laboratory of Molecular Biology (LMB), Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Holger Dinkel
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Markus Seiler
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Aidan Budd
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J. Gibson
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Norman E. Davey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department
of Physiology, University of California, San Francisco, San Francisco, California 94143, United States
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24
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Vicha A, Taieb D, Pacak K. Current views on cell metabolism in SDHx-related pheochromocytoma and paraganglioma. Endocr Relat Cancer 2014; 21:R261-77. [PMID: 24500761 PMCID: PMC4016161 DOI: 10.1530/erc-13-0398] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Warburg's metabolic hypothesis is based on the assumption that a cancer cell's respiration must be under attack, leading to its damage, in order to obtain increased glycolysis. Although this may not apply to all cancers, there is some evidence proving that primarily abnormally functioning mitochondrial complexes are indeed related to cancer development. Thus, mutations in complex II (succinate dehydrogenase (SDH)) lead to the formation of pheochromocytoma (PHEO)/paraganglioma (PGL). Mutations in one of the SDH genes (SDHx mutations) lead to succinate accumulation associated with very low fumarate levels, increased glutaminolysis, the generation of reactive oxygen species, and pseudohypoxia. This results in significant changes in signaling pathways (many of them dependent on the stabilization of hypoxia-inducible factor), including oxidative phosphorylation, glycolysis, specific expression profiles, as well as genomic instability and increased mutability resulting in tumor development. Although there is currently no very effective therapy for SDHx-related metastatic PHEOs/PGLs, targeting their fundamental metabolic abnormalities may provide a unique opportunity for the development of novel and more effective forms of therapy for these tumors.
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Affiliation(s)
- Ales Vicha
- Department of Pediatric Hematology and Oncology, 2 Medical School, Charles University and University Hospital Motol, Prague, Czech Republic
| | - David Taieb
- Service Central de Biophysique et de Médecine Nucléaire, CERIMED Centre hospitalo-universitaire Timone, Marseille, France
- Département d’Oncologie Moléculaire, Centre de Recherche en Cancérologie de Marseille, Marseille, France
| | - Karel Pacak
- Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health, Bethesda, Maryland, 20892 USA
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25
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Hong WJ, Gotlib J. Hereditary erythrocytosis, thrombocytosis and neutrophilia. Best Pract Res Clin Haematol 2014; 27:95-106. [DOI: 10.1016/j.beha.2014.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 07/11/2014] [Indexed: 10/25/2022]
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26
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Toyoda H, Hirayama J, Sugimoto Y, Uchida K, Ohishi K, Hirayama M, Komada Y. Polycythemia and paraganglioma with a novel somatic HIF2A mutation in a male. Pediatrics 2014; 133:e1787-91. [PMID: 24819565 DOI: 10.1542/peds.2013-2419] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Recently, a new syndrome of paraganglioma, somatostatinoma, and polycythemia has been discovered (known as Pacak-Zhuang syndrome). This new syndrome, with somatic HIF2A gain-of-function mutations, has never been reported in male patients. We describe a male patient with Pacak-Zhuang syndrome who carries a newly discovered HIF2A mutation. Congenital polycythemias have diverse etiologies, including germline mutations in the oxygen-sensing pathway. These include von Hippel-Lindau (Chuvash polycythemia), prolyl hydroxylase domain-containing protein-2, and hypoxia-inducible factor-2α (HIF-2α). Somatic gain-of-function mutations in the gene encoding HIF-2α were reported in patients with paraganglioma and polycythemia and have been found exclusively in female patients. Through sequencing of the HIF2A using DNA from paraganglioma in 15-year-old male patient, we identified a novel mutation of HIF2A: a heterozygous C to A substitution at base 1589 in exon 12 of HIF2A. The mutation was not found in germline DNA from leukocytes. The C1589A mutations resulted in substitution of alanine 530 in the HIF-2α protein with glutamic acid. This mutation is undoubtedly associated with increased HIF-2α activity and increased protein half-life, because it affects the vicinity of the prolyl hydroxylase target residue, proline 531. To our knowledge, this is the first report describing Pacak-Zhuang syndrome with somatic gain-of-function mutation in HIF2A in a male patient. Congenital polycythemia of unknown origin should raise suspicion for the novel disorder Pacak-Zhuang syndrome, even in male patients.
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Affiliation(s)
| | | | | | - Keiichi Uchida
- Gastrointestinal and Pediatric Surgery, Mie University Graduate School of Medicine, Tsu, Japan; and
| | - Kohshi Ohishi
- Transfusion Service, Mie University Hospital, Tsu, Japan
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27
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Butler LM, Dzabic M, Bakker F, Davoudi B, Jeffery H, Religa P, Bojakowski K, Yaiw KC, Rahbar A, Söderberg-Naucler C. Human cytomegalovirus inhibits erythropoietin production. J Am Soc Nephrol 2014; 25:1669-78. [PMID: 24722450 DOI: 10.1681/asn.2013101125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Anemia is a feature of CKD and a complication of renal transplantation, often caused by impaired production of erythropoietin. The kidney is a target organ for human cytomegalovirus (hCMV) in such patients, but it is not known whether hCMV effects erythropoietin production. We found that kidneys from patients with CKD were positive for hCMV protein and that blood levels of hCMV IgG inversely correlated with red blood cell count. In mice, systemic murine cytomegalovirus infection decreased serum erythropoietin levels. In human erythropoietin-producing cells, hCMV inhibited hypoxia-induced expression of erythropoietin mRNA and protein. hCMV early gene expression was responsible, as ultraviolet-inactivated virus had no effect and valganciclovir treatment showed that late gene expression was nonessential. Hypoxia-induced gene transcription is controlled by the transcription factors hypoxia-inducible transcription factor (HIF)-1α and HIF2α, which are constitutively produced but stable only under low oxygen conditions. We found that hCMV inhibited constitutive production of HIF2α mRNA. HIF2α is thought to be the master regulator of erythropoietin transcription. Single-cell analysis revealed that nuclear accumulation of HIF2α was inhibited in hCMV-infected cells, and the extent of inhibition correlated with hCMV protein expression. Our findings suggest that renal hCMV infection could induce or exacerbate anemia in patients.
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Affiliation(s)
- Lynn M Butler
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Mensur Dzabic
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Frank Bakker
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Belghis Davoudi
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Hannah Jeffery
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Piotr Religa
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | | | - Koon-Chu Yaiw
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Afsar Rahbar
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
| | - Cecilia Söderberg-Naucler
- Department of Medicine, Centre for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden; and
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28
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Bento C, Percy MJ, Gardie B, Maia TM, van Wijk R, Perrotta S, Della Ragione F, Almeida H, Rossi C, Girodon F, Aström M, Neumann D, Schnittger S, Landin B, Minkov M, Randi ML, Richard S, Casadevall N, Vainchenker W, Rives S, Hermouet S, Ribeiro ML, McMullin MF, Cario H, Chauveau A, Gimenez-Roqueplo AP, Bressac-de-Paillerets B, Altindirek D, Lorenzo F, Lambert F, Dan H, Gad-Lapiteau S, Catarina Oliveira A, Rossi C, Fraga C, Taradin G, Martin-Nuñez G, Vitória H, Diaz Aguado H, Palmblad J, Vidán J, Relvas L, Ribeiro ML, Luigi Larocca M, Luigia Randi M, Pedro Silveira M, Percy M, Gross M, Marques da Costa R, Beshara S, Ben-Ami T, Ugo V. Genetic basis of congenital erythrocytosis: mutation update and online databases. Hum Mutat 2013; 35:15-26. [PMID: 24115288 DOI: 10.1002/humu.22448] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 09/13/2013] [Indexed: 12/15/2022]
Abstract
Congenital erythrocytosis (CE), or congenital polycythemia, represents a rare and heterogeneous clinical entity. It is caused by deregulated red blood cell production where erythrocyte overproduction results in elevated hemoglobin and hematocrit levels. Primary congenital familial erythrocytosis is associated with low erythropoietin (Epo) levels and results from mutations in the Epo receptor gene (EPOR). Secondary CE arises from conditions causing tissue hypoxia and results in increased Epo production. These include hemoglobin variants with increased affinity for oxygen (HBB, HBA mutations), decreased production of 2,3-bisphosphoglycerate due to BPGM mutations, or mutations in the genes involved in the hypoxia sensing pathway (VHL, EPAS1, and EGLN1). Depending on the affected gene, CE can be inherited either in an autosomal dominant or recessive mode, with sporadic cases arising de novo. Despite recent important discoveries in the molecular pathogenesis of CE, the molecular causes remain to be identified in about 70% of the patients. With the objective of collecting all the published and unpublished cases of CE the COST action MPN&MPNr-Euronet developed a comprehensive Internet-based database focusing on the registration of clinical history, hematological, biochemical, and molecular data (http://www.erythrocytosis.org/). In addition, unreported mutations are also curated in the corresponding Leiden Open Variation Database.
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Affiliation(s)
- Celeste Bento
- Department of Hematology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
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29
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Perrotta S, Stiehl DP, Punzo F, Scianguetta S, Borriello A, Bencivenga D, Casale M, Nobili B, Fasoli S, Balduzzi A, Cro L, Nytko KJ, Wenger RH, Della Ragione F. Congenital erythrocytosis associated with gain-of-function HIF2A gene mutations and erythropoietin levels in the normal range. Haematologica 2013; 98:1624-32. [PMID: 23716564 PMCID: PMC3789469 DOI: 10.3324/haematol.2013.088369] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/27/2013] [Indexed: 12/20/2022] Open
Abstract
Hypoxia-inducible factor 2α (HIF-2α) plays a pivotal role in the balancing of oxygen requirements throughout the body. The protein is a transcription factor that modulates the expression of a wide array of genes and, in turn, controls several key processes including energy metabolism, erythropoiesis and angiogenesis. We describe here the identification of two cases of familial erythrocytosis associated with heterozygous HIF2A missense mutations, namely Ile533Val and Gly537Arg. Ile533Val is a novel mutation and represents the genetic HIF2A change nearest to Pro-531, the primary hydroxyl acceptor residue, so far identified. The Gly537Arg missense mutation has already been described in familial erythrocytosis. However, our patient is the only described case of a de novo HIF2A mutation associated with the development of congenital polycythemia. Functional in vivo studies, based on exogenous expression of hybrid HIF-2α transcription factors, indicated that these genetic alterations lead to the stabilization of HIF-2α protein. All the identified polycythemic subjects with HIF2A mutations show serum erythropoietin in the normal range, independently of the hematocrit values and phlebotomy frequency. The erythroid precursors obtained from the peripheral blood of patients showed an altered phenotype, including an increased rate of growth and a modified expression of some HIF-2α target genes. These results suggest the novel proposal that polycythemia observed in subjects with HIF2A mutations might also be due to primary changes in hematopoietic cells and not only secondary to increased erythropoietin levels.
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Affiliation(s)
- Silverio Perrotta
- Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Second University of Naples, Naples, Italy
| | - Daniel P. Stiehl
- Institute of Physiology and Zürich Center for Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
| | - Francesca Punzo
- Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Second University of Naples, Naples, Italy
| | - Saverio Scianguetta
- Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Second University of Naples, Naples, Italy
| | - Adriana Borriello
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Debora Bencivenga
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
| | - Maddalena Casale
- Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Second University of Naples, Naples, Italy
| | - Bruno Nobili
- Dipartimento della Donna, del Bambino e di Chirurgia Generale e Specialistica, Second University of Naples, Naples, Italy
| | | | - Adriana Balduzzi
- Clinica Pediatrica, Ospedale San Gerardo, Università degli Studi di Milano Bicocca, Monza, Italy
| | - Lilla Cro
- UO Ematologia/CTMO, Fondazione IRCCS Cà Granda, Ospedale Maggiore, Policlinico, Milano, Italy
| | - Katarzyna J. Nytko
- Institute of Physiology and Zürich Center for Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
| | - Roland H. Wenger
- Institute of Physiology and Zürich Center for Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland
| | - Fulvio Della Ragione
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Naples, Italy
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30
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Rabinowitz MH. Inhibition of hypoxia-inducible factor prolyl hydroxylase domain oxygen sensors: tricking the body into mounting orchestrated survival and repair responses. J Med Chem 2013; 56:9369-402. [PMID: 23977883 DOI: 10.1021/jm400386j] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hypoxia-inducible factor (HIF) is an oxygen-sensitive dimeric transcription factor that responds to pathophysiologically low O2 tensions via up-regulation, which leads to an orchestrated biological response to hypoxia. The HIF prolyl hydroxylase domain (PHD) enzymes are non-heme, iron-containing dioxygenases requiring for activity both molecular oxygen and 2-oxoglutarate that, under normoxia, selectively hydroxylate proline residues of HIF, initiating proteosomal degradation of the latter. The dependence of HIF protein levels on the concentration of O2 present, mediated by the PHD enzymes, forms the basis for one of the most significant biological sensor systems of tissue oxygenation in response to ischemic and inflammatory events. Consequently, pharmacological inhibition of PHD enzymes, leading to stabilization of HIF, may be of considerable therapeutic potential in treating conditions of tissue stress and injury. This Perspective reviews the PHDs and small molecule drug discovery efforts. A critical view of this challenging field is offered, which addresses potential concerns and highlights exciting possibilities for the future.
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Affiliation(s)
- Michael H Rabinowitz
- Janssen Pharmaceutical Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States
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Abstract
Myeloproliferative neoplasms (MPNs) are haematological disorders characterized by an overproduction of mature myeloid cells with a tendency to transform to acute myeloid leukaemia. Clonal proliferation of myeloid progenitor cells is driven by somatically acquired mutations, most notably JAK2 V617F, but there are important features relating to pathogenesis and phenotypic diversity that cannot be explained by acquired mutations alone. In this review we consider what is currently known about the role that inherited factors play in the development and biology of both sporadic and familial forms of MPN. Although most MPN cases appear to be sporadic, familial predisposition has been recognized for many years in a subset of cases and epidemiological studies have indicated the presence of common susceptibility alleles. Currently the JAK2 46/1 haplotype (also referred to as 'GGCC') is the strongest known predisposition factor for sporadic MPNs carrying a JAK2 V617F mutation, explaining a large proportion of the heritability of this disorder. Less is known about what genetic variants predispose to MPNs that lack JAK2 V617F, but there have been recent reports of interesting associations in biologically plausible candidates, and more loci are set to emerge with the application of systematic genome-wide association methodologies. Several highly penetrant predisposition variants that affect erythropoietin signalling, thrombopoietin signalling or oxygen sensing have been characterized in families with nonclonal hereditary erythrocytosis or thrombocytosis, but much less is known about familial predisposition to true clonal MPN. The heterogeneous pattern of inheritance and presumed genetic heterogeneity in these families makes analysis difficult, but whole exome or genome sequencing should provide novel insights into these elusive disorders.
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Affiliation(s)
- Amy V Jones
- Wessex Regional Genetics Laboratory, Salisbury, UK, Faculty of Medicine, University of Southampton, Southampton, UK
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32
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Abstract
In this issue of Endocrine-Related Cancer, Toledo et al. report the identification of activating mutations in the HIF2 (EPAS1) transcription factor in a subset of sporadic pheochromocytomas and paragangliomas. These findings add significantly to an evolving and complex story of the role of hypoxic gene response pathways in human endocrine neoplasia.
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Affiliation(s)
- Eamonn R Maher
- Department of Medical Genetics, University of Cambridge, Cambridge, UK.
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33
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Tan Q, Kerestes H, Percy MJ, Pietrofesa R, Chen L, Khurana TS, Christofidou-Solomidou M, Lappin TRJ, Lee FS. Erythrocytosis and pulmonary hypertension in a mouse model of human HIF2A gain of function mutation. J Biol Chem 2013; 288:17134-44. [PMID: 23640890 DOI: 10.1074/jbc.m112.444059] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The central pathway for oxygen-dependent control of red cell mass is the prolyl hydroxylase domain protein (PHD):hypoxia inducible factor (HIF) pathway. PHD site specifically prolyl hydroxylates the transcription factor HIF-α, thereby targeting the latter for degradation. Under hypoxia, this modification is attenuated, allowing stabilized HIF-α to activate target genes, including that for erythropoietin (EPO). Studies employing genetically modified mice point to Hif-2α, one of two main Hif-α isoforms, as being the critical regulator of Epo in the adult mouse. More recently, erythrocytosis patients with heterozygous point mutations in the HIF2A gene have been identified; whether these mutations were polymorphisms unrelated to the phenotype could not be ruled out. In the present report, we characterize a mouse line bearing a G536W missense mutation in the Hif2a gene that corresponds to the first such human mutation identified (G537W). We obtained mice bearing both heterozygous and homozygous mutations at this locus. We find that these mice display, in a mutation dose-dependent manner, erythrocytosis and pulmonary hypertension with a high degree of penetrance. These findings firmly establish missense mutations in HIF-2α as a cause of erythrocytosis, highlight the importance of this HIF-α isoform in erythropoiesis, and point to physiologic consequences of HIF-2α dysregulation.
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Affiliation(s)
- Qiulin Tan
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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34
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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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35
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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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36
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Percy MJ, Chung YJ, Harrison C, Mercieca J, Hoffbrand AV, Dinardo CL, Santos PCJL, Fonseca GHH, Gualandro SFM, Pereira AC, Lappin TRJ, McMullin MF, Lee FS. Two new mutations in the HIF2A gene associated with erythrocytosis. Am J Hematol 2012; 87:439-42. [PMID: 22367913 DOI: 10.1002/ajh.23123] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/08/2012] [Accepted: 01/11/2012] [Indexed: 12/29/2022]
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Simonson TS, McClain DA, Jorde LB, Prchal JT. Genetic determinants of Tibetan high-altitude adaptation. Hum Genet 2011; 131:527-33. [PMID: 22068265 DOI: 10.1007/s00439-011-1109-3] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 10/25/2011] [Indexed: 12/31/2022]
Abstract
Some highland populations have genetic adaptations that enable their successful existence in a hypoxic environment. Tibetans are protected against many of the harmful responses exhibited by non-adapted populations upon exposure to severe hypoxia, including elevated hemoglobin concentration (i.e., polycythemia). Recent studies have highlighted several genes subject to natural selection in native high-altitude Tibetans. Three of these genes, EPAS1, EGLN1 and PPARA, regulate or are regulated by hypoxia inducible factor, a principal controller of erythropoiesis and other organismal functions. Uncovering the molecular basis of hypoxic adaptation should have implications for understanding hematological and other adaptations involved in hypoxia tolerance. Because the hypoxia response involves a variety of cardiovascular, pulmonary and metabolic functions, this knowledge would improve our understanding of disease mechanisms and could ultimately be translated into targeted therapies for oxygen deprivation, cardiopulmonary and cerebral pathologies, and metabolic disorders such as diabetes and obesity.
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Affiliation(s)
- Tatum S Simonson
- Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA
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Lee FS, Percy MJ. The HIF pathway and erythrocytosis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2011; 6:165-92. [PMID: 20939709 DOI: 10.1146/annurev-pathol-011110-130321] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Because of the central role that red blood cells play in the delivery of oxygen to tissues of the body, red blood cell mass must be controlled at precise levels. The glycoprotein hormone erythropoietin (EPO) regulates red blood cell mass. EPO transcription, in turn, is regulated by a distinctive oxygen-sensing mechanism. In this pathway, prolyl hydroxylase domain protein (PHD) site-specifically hydroxylates the α-subunit of the transcription factor hypoxia-inducible factor α (HIF-α), thereby targeting the latter for degradation by the von Hippel-Lindau tumor-suppressor protein (VHL). Under hypoxic conditions, this posttranslational modification of HIF-α is inhibited, which stabilizes it and promotes the transcriptional activation of genes, including that for EPO. Rare patients with erythrocytosis have mutations in the genes encoding for PHD2, HIF-2α, and VHL, which implicates these proteins as critical to the proper control of red blood cell mass in humans.
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Affiliation(s)
- Frank S Lee
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA.
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Abstract
Erythrocytosis is present when there is an increase in the red cell mass, usually accompanied by an elevated hemoglobin and hematocrit. This occurs when there is an intrinsic defect in the erythroid component of the bone marrow or for secondary reasons when an increase in erythropoietin production drives red cell production. In normoxic conditions, HIF-α interacts with the other proteins in the HIF pathway and is destroyed, but in hypoxic conditions, HIF-α binds to HIF-β and alters the expression of downstream genes, including the erythropoietin gene. The end result is an increase in erythropoietin production. Mutations in any of the genes in the HIF pathway could lead to changed proteins, abnormalities in the degradation of HIF-α and, ultimately, result in increased erythropoietin levels. A number of mutations in the VHL, PHD2, and HIF2A genes have been identified in individuals. These mutations lead to erythrocytosis. The clinical results of these mutations may include some major thromboembolic events in young patients.
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Affiliation(s)
- Mary Frances McMullin
- Department of Haematology, Belfast City Hospital, Queen's University Belfast, Northern Ireland, UK.
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Abstract
INTRODUCTION The hypoxia-inducible factor (HIF) system mediates the body's response to hypoxia, locally, inducing angiogenesis and a shift to anaerobic metabolism, and systemically, increasing red cell mass in anemia. HIF prolyl hydroxylases (HIF-PH) modify HIF, decreasing its activity. Increasing HIF activity through inhibition of HIF-PH may provide an alternative treatment for anemia and may protect against damage related to ischemia-reperfusion. AREAS COVERED The review discusses the basic science underpinnings of the HIF system and the clinical effects of the HIF system and its pharmacologic manipulation. EXPERT OPINION Manipulation of the HIF system may improve outcomes in anemia by bypassing the effective iron deficiency found in anemia of chronic disease and by increasing red cell mass without supraphysiologic increases in erythropoietin. HIF-PH may also find a clinical use in the prevention of ischemia-reperfusion damage in strokes, cardiac ischemia, ischemic renal failure, etc.
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Majmundar AJ, Wong WJ, Simon MC. Hypoxia-inducible factors and the response to hypoxic stress. Mol Cell 2010; 40:294-309. [PMID: 20965423 PMCID: PMC3143508 DOI: 10.1016/j.molcel.2010.09.022] [Citation(s) in RCA: 1678] [Impact Index Per Article: 119.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Revised: 08/20/2010] [Accepted: 09/21/2010] [Indexed: 02/06/2023]
Abstract
Oxygen (O(2)) is an essential nutrient that serves as a key substrate in cellular metabolism and bioenergetics. In a variety of physiological and pathological states, organisms encounter insufficient O(2) availability, or hypoxia. In order to cope with this stress, evolutionarily conserved responses are engaged. In mammals, the primary transcriptional response to hypoxic stress is mediated by the hypoxia-inducible factors (HIFs). While canonically regulated by prolyl hydroxylase domain-containing enzymes (PHDs), the HIFα subunits are intricately responsive to numerous other factors, including factor-inhibiting HIF1α (FIH1), sirtuins, and metabolites. These transcription factors function in normal tissue homeostasis and impinge on critical aspects of disease progression and recovery. Insights from basic HIF biology are being translated into pharmaceuticals targeting the HIF pathway.
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Affiliation(s)
- Amar J Majmundar
- Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Yan L, Colandrea VJ, Hale JJ. Prolyl hydroxylase domain-containing protein inhibitors as stabilizers of hypoxia-inducible factor: small molecule-based therapeutics for anemia. Expert Opin Ther Pat 2010; 20:1219-45. [PMID: 20698812 DOI: 10.1517/13543776.2010.510836] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
IMPORTANCE OF THE FIELD Anemia caused by chronic kidney disease and other chronic diseases or conditions can be managed by the treatment of biologic-based erythropoiesis stimulating agents (ESAs). Although these ESAs are successful in treating these anemic conditions, a small molecule-based anti-anemia medicine can potentially revolutionize the treatment of anemia by bringing convenience to patients and being cost effective. Prolyl hydroxylase domain-containing protein (PHD) inhibitors may provide an opportunity for the development of small molecule anti-anemia medicines. AREAS COVERED IN THIS REVIEW This review covers efforts to target PHD enzymes for stabilization of hypoxia-inducible factor (HIF)-alpha subunits under normal oxygen levels as an attractive strategy to upregulate the expression of erythropoietin and genes involved in iron metabolism for the treatment of anemia. WHAT THE READER WILL GAIN The reader will gain a brief summary of recent advances in HIF and PHD biology and a review of patents/patent applications on the subject of PHD inhibitors as HIF stabilizers for the treatment of anemia. TAKE HOME MESSAGE Several classes of PHD enzyme inhibitors have been disclosed and several are currently in clinical trials for the development of small molecule-based therapeutics for the treatment of anemia.
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Affiliation(s)
- Lin Yan
- Department of Medicinal Chemistry, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA.
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Wenger RH, Hoogewijs D. Regulated oxygen sensing by protein hydroxylation in renal erythropoietin-producing cells. Am J Physiol Renal Physiol 2010; 298:F1287-96. [PMID: 20219824 DOI: 10.1152/ajprenal.00736.2009] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The kidney is a major site of systemic oxygen sensing, regulating blood erythrocyte and hence oxygen content by hypoxia-inducible erythropoietin (Epo) expression. A constant ratio between blood perfusion and oxygen consumption, a stable corticomedullary oxygen gradient, and a relatively low tissue Po(2) are the prerequisites for the function of renal Epo-producing and oxygen-sensing (REPOS) cells, which are located in the juxtamedullary cortex. In kidney disease, renal oxygen consumption is decreased, leading to an increase in Po(2), dysfunction of REPOS cells, and anemia. The molecular principles of cellular oxygen sensing have been elucidated in the last few years, and genetically altered mouse models as well as hereditary diseases causing erythrocytosis have clarified the oxygen-signaling cascade leading to increased Epo expression in REPOS cells. However, the consequences of a number of recently discovered factors for the regulation of oxygen signaling in REPOS cells are unclear, asking for novel cell culture models which might be hampered by the putative neuron-like nature of this enigmatic cell type.
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Affiliation(s)
- Roland H Wenger
- Institute of Physiology and Zürich Center for Integrative Human Physiology ZIHP, University of Zürich, Zürich, Switzerland.
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van Wijk R, Sutherland S, Van Wesel ACW, Huizinga EG, Percy MJ, Bierings M, Lee FS. Erythrocytosis associated with a novel missense mutation in the HIF2A gene. Haematologica 2009; 95:829-32. [PMID: 20007141 DOI: 10.3324/haematol.2009.017582] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The ERYTHROPOIETIN (EPO) gene is regulated by the transcription factor Hypoxia Inducible Factor-alpha (HIF-alpha). In this pathway, Prolyl Hydroxylase Domain protein 2 (PHD2) hydroxylates two prolyl residues in HIF-alpha, which in turn promotes HIF-alpha degradation by the von Hippel Lindau (VHL) protein. Evidence that HIF-2alpha is the important isoform for EPO regulation in humans comes from the recent observation that mutations in the HIF2A gene are associated with cases of erythrocytosis. We report here a new erythrocytosis-associated mutation, p.Asp539Glu, in the HIF2A gene. Similar to all reported cases, the affected residue is in close vicinity and C-terminal to the primary hydroxylation site in HIF-2alpha, Pro531. This mutation, however, is notable in producing a rather subtle amino acid substitution. Nonetheless, we find that this mutation compromises binding of HIF-2alpha to both PHD2 and VHL, and we propose that this mutation is the cause of erythrocytosis in this individual.
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Affiliation(s)
- Richard van Wijk
- Laboratory for Red Blood Cell Research, Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht, the Netherlands
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McMullin MF. Idiopathic erythrocytosis: a disappearing entity. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2009; 2009:629-635. [PMID: 20008248 DOI: 10.1182/asheducation-2009.1.629] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Erythrocytosis results when there is an increased red cell mass and thus an increased hemoglobin. The causes can be divided into primary intrinsic defects of the erythroid progenitor cell and secondary defects, where factors external to the erythroid compartment are responsible. Both can then be further divided into congenital and acquired categories. Congenital causes include mutations of the erythropoietin receptor and defects of the oxygen-sensing pathway including VHL, PHD2 and HIF2A mutations. When fully investigated there remain a number of patients in whom no cause can be elucidated who are currently described as having idiopathic erythrocytosis. Investigation should start with a full history and examination. Having eliminated the common entity polycythemia vera, further direction for investigation is guided by the erythropoietin level. Clinical consequences of the various erythrocytoses are not clear, but in some groups thromboembolic events have been described in young patients. Evidence is lacking to define best management, but aspirin and venesection to a target hematocrit should be considered.
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Affiliation(s)
- Mary Frances McMullin
- Centre for Cancer Research and Cell Biology, Queen's University, Belfast, N. Ireland.
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