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Sharma P, Bhatia P, Singh M, Jamwal M, Pallavelangini S, Das R, Malhotra P, Attri SV, Ducamp S, Fleming MD, Trehan A. Comprehensive Genomic Analysis Identifies a Diverse Landscape of Sideroblastic and Nonsideroblastic Iron-Related Anemias with Novel and Pathogenic Variants in an Iron-Deficient Endemic Setting. J Mol Diagn 2024; 26:430-444. [PMID: 38360212 DOI: 10.1016/j.jmoldx.2024.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/19/2024] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
Inherited iron metabolism defects are possibly missed or underdiagnosed in iron-deficient endemic settings because of a lack of awareness or a methodical screening approach. Hence, we systematically evaluated anemia cases (2019 to 2021) based on clinical phenotype, normal screening tests (high-performance liquid chromatography, α gene sequencing, erythrocyte sedimentation rate, C-reactive protein, and tissue transglutaminase), and abnormal iron profile by targeted next-generation sequencing (26-gene panel) supplemented with whole-exome sequencing, multiplex ligation probe amplification/mitochondrial DNA sequencing, and chromosomal microarray. Novel variants in ALAS2, STEAP3, and HSPA9 genes were functionally validated. A total of 290 anemia cases were screened, and 41 (14%) enrolled for genomic testing as per inclusion criteria. Comprehensive genomic testing revealed pathogenic variants in 23 of 41 cases (56%). Congenital sideroblastic anemia was the most common diagnosis (14/23; 61%), with pathogenic variations in ALAS2 (n = 6), SLC25A38 (n = 3), HSPA9 (n = 2) and HSCB, SLC19A2, and mitochondrial DNA deletion (n = 1 each). Nonsideroblastic iron defects included STEAP3-related microcytic anemia (2/23; 8.7%) and hypotransferrenemia (1/23; 4.3%). A total of 6 of 22 cases (27%) revealed a non-iron metabolism gene defect on whole-exome sequencing. Eleven novel variants (including variants of uncertain significance) were noted in 13 cases. Genotype-phenotype correlation revealed a significant association of frameshift/nonsense/splice variants with lower presentation age (0.8 months versus 9 years; P < 0.01) compared with missense variants. The systematic evaluation helped uncover an inherited iron defect in 41% (17/41) of cases, suggesting the need for active screening and awareness for these rare diseases in an iron-deficient endemic population.
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Affiliation(s)
- Pankaj Sharma
- Pediatric Haematology Oncology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Prateek Bhatia
- Pediatric Haematology Oncology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
| | - Minu Singh
- Pediatric Haematology Oncology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Manu Jamwal
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Swetha Pallavelangini
- Pediatric Haematology Oncology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Reena Das
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Pankaj Malhotra
- Department of Clinical Haematology and Medical Oncology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Savita V Attri
- Pediatric Biochemistry Laboratory, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sarah Ducamp
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts
| | - Mark D Fleming
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts
| | - Amita Trehan
- Pediatric Haematology Oncology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
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Iron Deficiency Caused by Intestinal Iron Loss-Novel Candidate Genes for Severe Anemia. Genes (Basel) 2021; 12:genes12121869. [PMID: 34946818 PMCID: PMC8700796 DOI: 10.3390/genes12121869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 02/06/2023] Open
Abstract
The adult human body contains about 4 g of iron. About 1-2 mg of iron is absorbed every day, and in healthy individuals, the same amount is excreted. We describe a patient who presents with severe iron deficiency anemia with hemoglobin levels below 6 g/dL and ferritin levels below 30 ng/mL. Although red blood cell concentrates and intravenous iron have been substituted every month for years, body iron stores remain depleted. Diagnostics have included several esophago-gastro-duodenoscopies, colonoscopies, MRI of the liver, repetitive bone marrow biopsies, psychological analysis, application of radioactive iron to determine intact erythropoiesis, and measurement of iron excretion in urine and feces. Typically, gastrointestinal bleeding is a major cause of iron loss. Surprisingly, intestinal iron excretion in stool in the patient was repetitively increased, without gastrointestinal bleeding. Furthermore, whole exome sequencing was performed in the patient and additional family members to identify potential causative genetic variants that may cause intestinal iron loss. Under different inheritance models, several rare mutations were identified, two of which (in CISD1 and KRI1) are likely to be functionally relevant. Intestinal iron loss in the current form has not yet been described and is, with high probability, the cause of the severe iron deficiency anemia in this patient.
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Ravasi G, Pelucchi S, Bertola F, Capelletti MM, Mariani R, Piperno A. Identification of Novel Mutations by Targeted NGS Panel in Patients with Hyperferritinemia. Genes (Basel) 2021; 12:genes12111778. [PMID: 34828384 PMCID: PMC8623017 DOI: 10.3390/genes12111778] [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: 10/21/2021] [Revised: 11/03/2021] [Accepted: 11/06/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Several inherited diseases cause hyperferritinemia with or without iron overload. Differential diagnosis is complex and requires an extensive work-up. Currently, a clinical-guided approach to genetic tests is performed based on gene-by-gene sequencing. Although reasonable, this approach is expensive and time-consuming and Next Generation Sequencing (NGS) technology may provide cheaper and quicker large-scale DNA sequencing. METHODS We analysed 36 patients with non-HFE-related hyperferritinemia. Liver iron concentration was measured in 33 by magnetic resonance. A panel of 25 iron related genes was designed using SureDesign software. Custom libraries were generated and then sequenced using Ion Torrent PGM. RESULTS We identified six novel mutations in SLC40A1, three novel and one known mutation in TFR2, one known mutation and a de-novo deletion in HJV, and a novel mutation in HAMP in ten patients. In silico analyses supported the pathogenic role of the mutations. CONCLUSIONS Our results support the use of an NGS-based panel in selected patients with hyperferritinemia in a tertiary center for iron metabolism disorders. However, 26 out of 36 patients did not show genetic variants that can individually explain hyperferritinemia and/or iron overload suggesting the existence of other genetic defects or gene-gene and gene-environment interactions needing further studies.
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Affiliation(s)
- Giulia Ravasi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
| | - Sara Pelucchi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
| | - Francesca Bertola
- Medical Genetics, S. Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
| | - Martina Maria Capelletti
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
| | - Raffaella Mariani
- Disorders of Iron Metabolism, Centre for Rare Diseases, San Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
| | - Alberto Piperno
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
- Medical Genetics, S. Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
- Disorders of Iron Metabolism, Centre for Rare Diseases, San Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
- Correspondence: ; Tel.: +39-03-9233-3461
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Rusu IG, Suharoschi R, Vodnar DC, Pop CR, Socaci SA, Vulturar R, Istrati M, Moroșan I, Fărcaș AC, Kerezsi AD, Mureșan CI, Pop OL. Iron Supplementation Influence on the Gut Microbiota and Probiotic Intake Effect in Iron Deficiency-A Literature-Based Review. Nutrients 2020; 12:E1993. [PMID: 32635533 PMCID: PMC7400826 DOI: 10.3390/nu12071993] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 12/15/2022] Open
Abstract
Iron deficiency in the human body is a global issue with an impact on more than two billion individuals worldwide. The most important functions ensured by adequate amounts of iron in the body are related to transport and storage of oxygen, electron transfer, mediation of oxidation-reduction reactions, synthesis of hormones, the replication of DNA, cell cycle restoration and control, fixation of nitrogen, and antioxidant effects. In the case of iron deficiency, even marginal insufficiencies may impair the proper functionality of the human body. On the other hand, an excess in iron concentration has a major impact on the gut microbiota composition. There are several non-genetic causes that lead to iron deficiencies, and thus, several approaches in their treatment. The most common methods are related to food fortifications and supplements. In this review, following a summary of iron metabolism and its health implications, we analyzed the scientific literature for the influence of iron fortification and supplementation on the gut microbiome and the effect of probiotics, prebiotics, and/or synbiotics in iron absorption and availability for the organism.
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Affiliation(s)
- Ioana Gabriela Rusu
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Ramona Suharoschi
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Dan Cristian Vodnar
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Carmen Rodica Pop
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Sonia Ancuța Socaci
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Romana Vulturar
- Department of Molecular Sciences, University of Medicine and Pharmacy Iuliu Hatieganu, 400349 Cluj-Napoca, Romania;
- Cognitive Neuroscience Laboratory, University Babes-Bolyai, 400327 Cluj-Napoca, Romania
| | - Magdalena Istrati
- Regional Institute of Gastroenterology and Hepatology “Prof. Dr. Octavian Fodor”, 400158 Cluj-Napoca, Romania;
| | - Ioana Moroșan
- Faculty of Medicine, University of Medicine and Pharmacy “Iuliu Hatieganu”, 400349 Cluj-Napoca, Romania;
| | - Anca Corina Fărcaș
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Andreea Diana Kerezsi
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Carmen Ioana Mureșan
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
| | - Oana Lelia Pop
- Department of Food Science, University of Agricultural Science and Veterinary Medicine, 400372 Cluj-Napoca, Romania; (I.G.R.); (R.S.); (D.C.V.); (C.R.P.); (S.A.S.); (A.C.F.); (A.D.K.); (C.I.M.)
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Rzymski P, Ganz T. Comment on "Serum Hepcidin and Soluble Transferrin Receptor in the Assessment of Iron Metabolism in Children on a Vegetarian Diet". Biol Trace Elem Res 2018; 185:252-254. [PMID: 29322429 PMCID: PMC6097060 DOI: 10.1007/s12011-018-1241-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/03/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Piotr Rzymski
- Department of Environmental Medicine, Poznan University of Medical Sciences, Poznań, Poland.
| | - Tomas Ganz
- Departments of Medicine and Pathology, David Geffen School of Medicine, University of California, Los Angeles, USA
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Iron Overload in the Liver of 2 Children: Nonalcoholic Steatohepatitis and Juvenile Hemochromatosis. J Pediatr Hematol Oncol 2017; 39:466-469. [PMID: 28067690 DOI: 10.1097/mph.0000000000000752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Iron overload disorders are hereditary hemochromatosis and secondary etiologies other than hereditary hemochromatosis. We describe 2 boys presenting with iron overload. Juvenile hemochromatosis and nonalcoholic steatohepatitis (NASH) related iron overload are the genetic and secondary causes, respectively. OBSERVATIONS Both patients benefited from phlebotomy even if they had different etiologies. CONCLUSIONS In childhood, the diagnosis of iron overload syndromes is crucial because they do not confront us with obvious symptoms and findings. Early initiation of a phlebotomy program can prevent mortality. NASH might lead to iron overload and iron overload might aggravate the clinical course of NASH.
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Identification of hereditary hemochromatosis pedigrees and a novel SLC40A1 mutation in Chinese population. Blood Cells Mol Dis 2017; 63:34-36. [DOI: 10.1016/j.bcmd.2017.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 11/18/2022]
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Comparison of myocardial T1 and T2 values in 3 T with T2* in 1.5 T in patients with iron overload and controls. Int J Hematol 2016; 103:530-6. [PMID: 26872908 DOI: 10.1007/s12185-016-1950-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/26/2016] [Accepted: 01/26/2016] [Indexed: 12/31/2022]
Abstract
Myocardial iron quantification remains limited to 1.5 T systems with T2* measurement. The present study aimed at comparing myocardial T2* values at 1.5 T to T1 and T2 mapping at 3.0 T in patients with iron overload and healthy controls. A total of 17 normal volunteers and seven patients with a history of myocardial iron overload were prospectively enrolled. Mid-interventricular septum T2*, native T1 and T2 times were quantified on the same day, using a multi-echo gradient-echo sequence at 1.5 T and T1 and T2 mapping sequences at 3.0 T, respectively. Subjects with myocardial iron overload (T2* < 20 ms) in comparison with those without had significantly lower mean myocardial T1 times (868.9 ± 120.2 vs. 1170.3 ± 25.0 ms P = 0.005 respectively) and T2 times (34.9 ± 4.7 vs. 45.1 ± 2.0 ms P = 0.007 respectively). 3 T T1 and T2 times strongly correlated with 1.5 T, T2* times (Pearson's r = 0.95 and 0.91 respectively). T1 and T2 measures presented less variability than T2* in inter- and intra-observer analysis. Native myocardial T1 and T2 times at 3 T correlate closely with T2* times at 1.5 T and may be useful for myocardial iron overload quantification.
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Abstract
Iron is essential for life because it is indispensable for several biological reactions, such as oxygen transport, DNA synthesis, and cell proliferation. Over the past few years, our understanding of iron metabolism and its regulation has changed dramatically. New disorders of iron metabolism have emerged, and the role of iron as a cofactor in other disorders has begun to be recognized. The study of genetic conditions such as hemochromatosis and iron-refractory iron deficiency anemia (IRIDA) has provided crucial insights into the molecular mechanisms controlling iron homeostasis. In the future, these advances may be exploited to improve treatment of both genetic and acquired iron disorders. IRIDA is caused by mutations in TMPRSS6, the gene encoding matriptase-2, which downregulates hepcidin expression under conditions of iron deficiency. The typical features of this disorder are hypochromic, microcytic anemia with a very low mean corpuscular volume of erythrocytes, low transferrin saturation, no (or inadequate) response to oral iron, and only a partial response to parenteral iron. In contrast to classic iron deficiency anemia, serum ferritin levels are usually low-normal, and serum or urinary hepcidin levels are inappropriately high for the degree of anemia. Although the number of cases reported thus far in the literature does not exceed 100, this disorder is considered the most common of the “atypical” microcytic anemias. The aim of this review is to share the current knowledge on IRIDA and increase awareness in this field.
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Affiliation(s)
- Ebru Yılmaz Keskin
- Samsun Education and Research Hospital, Clinic of Pediatric Hematology and Oncology, Samsun, Turkey. E-mail:
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Abstract
Iron is an essential trace element for multicellular organisms and nearly all microorganisms. Although iron is abundant in the environment, common forms of iron are minimally soluble and therefore poorly accessible to biological organisms. Microorganisms entering a mammalian host face multiple mechanisms that further restrict their ability to obtain iron and thereby limit their pathogenicity. Iron levels also modulate host defence, as iron content in macrophages regulates their cytokine production. Here, we review recent advances that highlight the role of systemic and cellular iron-regulating mechanisms in protecting hosts from infection, emphasizing aspects that are applicable to human health and disease.
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Affiliation(s)
- Tomas Ganz
- 1] Department of Medicine, David Geffen School of Medicine at University of California. [2] Department of Pathology, David Geffen School of Medicine at University of California, Los Angeles, California 90095-1690, USA
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at University of California
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Chiabrando D, Mercurio S, Tolosano E. Heme and erythropoieis: more than a structural role. Haematologica 2015; 99:973-83. [PMID: 24881043 DOI: 10.3324/haematol.2013.091991] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Erythropoiesis is the biological process that consumes the highest amount of body iron for heme synthesis. Heme synthesis in erythroid cells is finely coordinated with that of alpha (α) and beta (β)-globin, resulting in the production of hemoglobin, a tetramer of 2α- and 2β-globin chains, and heme as the prosthetic group. Heme is not only the structural component of hemoglobin, but it plays multiple regulatory roles during the differentiation of erythroid precursors since it controls its own synthesis and regulates the expression of several erythroid-specific genes. Heme is synthesized in developing erythroid progenitors by the stage of proerythroblast, through a series of eight enzymatic reactions divided between mitochondria and cytosol. Defects of heme synthesis in the erythroid lineage result in sideroblastic anemias, characterized by microcytic anemia associated to mitochondrial iron overload, or in erythropoietic porphyrias, characterized by porphyrin deposition in erythroid cells. Here, we focus on the heme biosynthetic pathway and on human erythroid disorders due to defective heme synthesis. The regulatory role of heme during erythroid differentiation is discussed as well as the heme-mediated regulatory mechanisms that allow the orchestration of the adaptive cell response to heme deficiency.
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Affiliation(s)
- Deborah Chiabrando
- Department of Molecular Biotechnology and Health Sciences and Molecular Biotechnology Center, University of Torino, Italy
| | - Sonia Mercurio
- Department of Molecular Biotechnology and Health Sciences and Molecular Biotechnology Center, University of Torino, Italy
| | - Emanuela Tolosano
- Department of Molecular Biotechnology and Health Sciences and Molecular Biotechnology Center, University of Torino, Italy
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Foka P, Dimitriadis A, Kyratzopoulou E, Giannimaras DA, Sarno S, Simos G, Georgopoulou U, Mamalaki A. A complex signaling network involving protein kinase CK2 is required for hepatitis C virus core protein-mediated modulation of the iron-regulatory hepcidin gene expression. Cell Mol Life Sci 2014; 71:4243-58. [PMID: 24718935 PMCID: PMC11114079 DOI: 10.1007/s00018-014-1621-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 02/25/2014] [Accepted: 03/24/2014] [Indexed: 12/18/2022]
Abstract
Hepatitis C virus (HCV) infection is associated with hepatic iron overload and elevated serum iron that correlate to poor antiviral responses. Hepcidin (HAMP), a 25-aa cysteine-rich liver-specific peptide, controls iron homeostasis. Its expression is up-regulated in inflammation and iron excess. HCV-mediated hepcidin regulation remains controversial. Chronic HCV patients possess relatively low hepcidin levels; however, elevated HAMP mRNA has been reported in HCV core transgenic mice and HCV replicon-expressing cells. We investigated the effect of HCV core protein on HAMP gene expression and delineated the complex interplay of molecular mechanisms involved. HCV core protein up-regulated HAMP promoter activity, mRNA, and secreted protein levels. Enhanced promoter activity was abolished by co-transfections of core with HAMP promoter constructs containing mutated/deleted BMP and STAT binding sites. Dominant negative constructs, pharmacological inhibitors, and silencing experiments against STAT3 and SMAD4 confirmed the participation of both pathways in HAMP gene regulation by core protein. STAT3 and SMAD4 expression levels were found increased in the presence of HCV core, which orchestrated SMAD4 translocation into the nucleus and STAT3 phosphorylation. To further understand the mechanisms governing the core effect, the role of the JAK/STAT-activating kinase CK2 was investigated. A CK2-dominant negative construct, a CK2-specific inhibitor, and RNAi interference abrogated the core-induced increase on HAMP promoter activity, mRNA, and protein levels, while CK2 acted in synergy with core to significantly enhance HAMP gene expression. Therefore, HCV core up-regulates HAMP gene transcription via a complex signaling network that requires both SMAD/BMP and STAT3 pathways and CK2 involvement.
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Affiliation(s)
- Pelagia Foka
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- Laboratory of Molecular Virology, Hellenic Pasteur Institute, Athens, Greece
| | - Alexios Dimitriadis
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Eleni Kyratzopoulou
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Dionysios A. Giannimaras
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Stefania Sarno
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - George Simos
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Urania Georgopoulou
- Laboratory of Molecular Virology, Hellenic Pasteur Institute, Athens, Greece
| | - Avgi Mamalaki
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
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Abstract
SIGNIFICANCE Iron is the most abundant transition metal in biology and an essential cofactor for many cellular enzymes. Iron homeostasis impairment is also a component of peripheral neuropathies. RECENT ADVANCES During the past years, much effort has been paid to understand the molecular mechanism involved in maintaining systemic iron homeostasis in mammals. This has been stimulated by the evidence that iron dyshomeostasis is an initial cause of several disorders, including genetic and sporadic neurodegenerative disorders. CRITICAL ISSUES However, very little has been done to investigate the physiological role of iron in peripheral nervous system (PNS), despite the development of suitable cellular and animal models. FUTURE DIRECTIONS To stimulate research on iron metabolism and peripheral neuropathy, we provide a summary of the knowledge on iron homeostasis in the PNS, on its transport across the blood-nerve barrier, its involvement in myelination, and we identify unresolved questions. Furthermore, we comment on the role of iron in iron-related disorder with peripheral component, in demyelinating and metabolic peripheral neuropathies.
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Affiliation(s)
- Sonia Levi
- 1 University Vita-Salute San Raffaele , Milan, Italy
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Cvejic A. From genome-wide association study hits to new insights into experimental hematology. Exp Hematol 2014; 42:630-6. [PMID: 24746874 DOI: 10.1016/j.exphem.2014.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 03/30/2014] [Accepted: 04/05/2014] [Indexed: 11/22/2022]
Abstract
Despite significant improvements in our knowledge of the mechanisms of normal and pathological hematopoiesis, our current understanding is most likely an oversimplification of the complexity of regulatory networks at play. Thus, considerable efforts have been made to catalogue the total sum of germline alterations in individual genomes affecting human hematopoiesis. These efforts ultimately led to the discovery of a large number of new genes not previously implicated in blood formation. Although identification of novel genes is important in revealing the profiles of genetic variations associated with normal hematopoiesis, further functional studies are necessary to improve our understanding of the mechanism(s) involved in these processes. In this review, we summarize the knowledge gained from genome-wide association studies to elucidate the relationship between genetics and blood cell traits. We discuss the most important recent advances, with an emphasis on functional follow-up studies that have been particularly useful in providing an insight into novel regulatory processes that influence blood cell formation and function. We also discuss potential future directions and challenges in the field.
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Affiliation(s)
- Ana Cvejic
- Department of Haematology, University of Cambridge, UK; Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.
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Abstract
Iron is one of the most important nonorganic substances that make life possible. Iron plays major roles in oxygen transport (eg, hemoglobin; -67% of total body iron [TBI]), short-term oxygen storage (eg, myoglobin; -3.5% of TBI), and energy generation (eg, cytochromes; -3% of TBI). Iron also serves vital roles in various nonheme-containing enzymes (-2% of TBI). Figure 1 lists heme-containing and nonheme iron-containing proteins. TBI is controlled by the rate of iron absorption; there are no physiologic mechanisms to excrete excess iron. Iron deficiency has many adverse consequences, including anemia, and in children, behavioral and learning disorders. Iron excess is toxic to the body, harming the heart, liver, skin, pancreatic islet beta cells, bones, joints, and pituitary gland. Maintaining proper iron balance is essential for maintaining homeostasis and health. TBI in adults normally ranges between 3.5 and 5.0 g. A total of 75% of TBI is functional, and 25% is stored within cells as ferritin or hemosiderin. Ferritin contains 24 subunits of light chains (L chains; 19.7 kDa) and heavy chains (H chains; 21.1 kDa). The L chains are encoded on chromosome 19q13.33 and are 175 amino acids long. The H chains are encoded on chromosome 11q1 and are 183 amino acids long. Each ferritin molecule can contain as many as approximately 4500 ferric ions. Because the major role of iron is in hemoglobin synthesis, this review will focus on iron, iron transport, and hematopoiesis.
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Abstract
Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta (TGF-β) superfamily of signaling molecules. In addition to protean roles in embryonic development, germ-line specification, and cellular differentiation, a central role in iron homeostasis has recently been demonstrated for certain BMPs. Specifically, BMP6 serves to relate hepatic iron stores to the hepatocellular expression of the iron-regulatory hormone hepcidin. This regulation occurs via cellular SMAD-signaling molecules and is strongly modulated by the BMP coreceptor hemojuvelin (HJV). Mutations in certain genes influencing signaling to hepcidin via the BMP/SMAD pathway are associated with human disorders of iron metabolism, such as hereditary hemochromatosis and iron-refractory iron-deficiency anemia. Evidence suggests that signals in addition to iron stores influence hepcidin expression via the BMP/SMAD pathway. This review summarizes the details of BMP/SMAD signaling, with a particular focus on its role in iron homeostasis and iron-related diseases.
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Affiliation(s)
- Nermi L Parrow
- Division of Molecular and Clinical Nutrition, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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Abstract
Anemia of inflammation (AI, also called anemia of chronic disease) is a common, typically normocytic, normochromic anemia that is caused by an underlying inflammatory disease. It is diagnosed when serum iron concentrations are low despite adequate iron stores, as evidenced by serum ferritin that is not low. In the setting of inflammation, it may be difficult to differentiate AI from iron deficiency anemia, and the 2 conditions may coexist. Treatment should focus on the underlying disease. Recent advances in molecular understanding of AI are stimulating the development of new pathophysiologically targeted experimental therapies.
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Affiliation(s)
- Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at UCLA, 37-055 CHS, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine at UCLA, 37-055 CHS, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA; Department of Pathology, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
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Abstract
Iron-overload disorders owing to genetic misregulation of iron acquisition are referred to as hereditary hemochromatosis (HH). The most prevalent genetic iron overload disorder in Caucasians is caused by mutations in the HFE gene, an atypical MHC class I molecule. Recent studies classified HFE/Hfe-HH as a liver disease with the primarily failure in the production of the liver iron hormone hepcidin in hepatocytes. Inadequate hepcidin expression signals for excessive iron absorption from the diet and iron deposition in tissues causing multiple organ damage and failure. This review focuses on the molecular actions of the HFE/Hfe and hepcidin in maintaining systemic iron homeostasis and approaches undertaken so far to combat iron overload in HFE/Hfe-HH. In the light of the recent investigations, novel roles of extra-hepatocytic Hfe are discussed raising a question to the relevance of the multipurpose functions of Hfe for the understanding of HH-associated pathologies.
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Affiliation(s)
- Maja Vujić
- Institute of General Zoology and Endocrinology, University of Ulm Ulm, Germany
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Mojzikova R, Koralkova P, Holub D, Zidova Z, Pospisilova D, Cermak J, Striezencova Laluhova Z, Indrak K, Sukova M, Partschova M, Kucerova J, Horvathova M, Divoky V. Iron status in patients with pyruvate kinase deficiency: neonatal hyperferritinaemia associated with a novel frameshift deletion in the PKLR gene (p.Arg518fs), and low hepcidin to ferritin ratios. Br J Haematol 2014; 165:556-63. [PMID: 24533562 DOI: 10.1111/bjh.12779] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 12/18/2013] [Indexed: 01/19/2023]
Abstract
Pyruvate kinase (PK) deficiency is an iron-loading anaemia characterized by chronic haemolysis, ineffective erythropoiesis and a requirement for blood transfusion in most cases. We studied 11 patients from 10 unrelated families and found nine different disease-causing PKLR mutations. Two of these mutations - the point mutation c.878A>T (p.Asp293Val) and the frameshift deletion c.1553delG (p.(Arg518Leufs*12)) - have not been previously described in the literature. This frameshift deletion was associated with an unusually severe phenotype involving neonatal hyperferritinaemia that is not typical of PK deficiency. No disease-causing mutations in genes associated with haemochromatosis could be found. Inappropriately low levels of hepcidin with respect to iron loading were detected in all PK-deficient patients with increased ferritin, confirming the predominant effect of accelerated erythropoiesis on hepcidin production. Although the levels of a putative hepcidin suppressor, growth differentiation factor-15, were increased in PK-deficient patients, no negative correlation with hepcidin was found. This result indicates the existence of another as-yet unidentified erythroid regulator of hepcidin synthesis in PK deficiency.
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Affiliation(s)
- Renata Mojzikova
- Department of Biology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
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Pretorius E, Bester J, Vermeulen N, Lipinski B, Gericke GS, Kell DB. Profound morphological changes in the erythrocytes and fibrin networks of patients with hemochromatosis or with hyperferritinemia, and their normalization by iron chelators and other agents. PLoS One 2014; 9:e85271. [PMID: 24416376 PMCID: PMC3887013 DOI: 10.1371/journal.pone.0085271] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 11/25/2013] [Indexed: 12/22/2022] Open
Abstract
It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs) may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH), as well as some who displayed hyperferritinemia (HF). Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators). These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded (‘free’) iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise.
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Affiliation(s)
- Etheresia Pretorius
- Department of Physiology, University of Pretoria, Arcadia, South Africa
- * E-mail:
| | - Janette Bester
- Department of Physiology, University of Pretoria, Arcadia, South Africa
| | - Natasha Vermeulen
- Department of Physiology, University of Pretoria, Arcadia, South Africa
| | - Boguslaw Lipinski
- Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | | | - Douglas B. Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, Lancs, United Kingdom
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Abstract
The iron hormone hepcidin and its receptor and cellular iron exporter ferroportin control the major fluxes of iron into blood plasma: intestinal iron absorption, the delivery of recycled iron from macrophages, and the release of stored iron from hepatocytes. Because iron losses are comparatively very small, iron absorption and its regulation by hepcidin and ferroportin determine total body iron content. Hepcidin is in turn feedback-regulated by plasma iron concentration and iron stores, and negatively regulated by the activity of erythrocyte precursors, the dominant consumers of iron. Hepcidin and ferroportin also play a role in host defense and inflammation, and hepcidin synthesis is induced by inflammatory signals including interleukin-6 and activin B. This review summarizes and discusses recent progress in molecular characterization of systemic iron homeostasis and its disorders, and identifies areas for further investigation.
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Bester J, Buys AV, Lipinski B, Kell DB, Pretorius E. High ferritin levels have major effects on the morphology of erythrocytes in Alzheimer's disease. Front Aging Neurosci 2013; 5:88. [PMID: 24367334 PMCID: PMC3853801 DOI: 10.3389/fnagi.2013.00088] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 11/20/2013] [Indexed: 12/21/2022] Open
Abstract
Introduction: Unliganded iron both contributes to the pathology of Alzheimer's disease (AD) and also changes the morphology of erythrocytes (RBCs). We tested the hypothesis that these two facts might be linked, i.e., that the RBCs of AD individuals have a variant morphology, that might have diagnostic or prognostic value. Methods: We included a literature survey of AD and its relationships to the vascular system, followed by a laboratory study. Four different microscopy techniques were used and results statistically compared to analyze trends between high and normal serum ferritin (SF) AD individuals. Results: Light and scanning electron microscopies showed little difference between the morphologies of RBCs taken from healthy individuals and from normal SF AD individuals. By contrast, there were substantial changes in the morphology of RBCs taken from high SF AD individuals. These differences were also observed using confocal microscopy and as a significantly greater membrane stiffness (measured using force-distance curves). Conclusion: We argue that high ferritin levels may contribute to an accelerated pathology in AD. Our findings reinforce the importance of (unliganded) iron in AD, and suggest the possibility both of an early diagnosis and some means of treating or slowing down the progress of this disease.
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Affiliation(s)
- Janette Bester
- Department of Physiology, Faculty of Health Sciences, University of Pretoria Arcadia, South Africa
| | - Antoinette V Buys
- Microscopy and Microanalysis Unit, University of Pretoria Arcadia, South Africa
| | | | - Douglas B Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester Lancs, UK
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria Arcadia, South Africa
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Magnetic resonance imaging of the pediatric liver: imaging of steatosis, iron deposition, and fibrosis. Magn Reson Imaging Clin N Am 2013; 21:669-80. [PMID: 24183519 DOI: 10.1016/j.mric.2013.05.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Traditionally, many diffuse diseases of the liver could only be diagnosed by liver biopsy. Although still considered the gold standard, liver biopsy is limited by its small sample size, invasive nature, and subjectivity of interpretation. There have been significant advances in functional magnetic resonance (MR) imaging of the liver. These advances now provide radiologists with the tools to evaluate the liver at the molecular level, allowing quantification of hepatic fat and iron, and enabling the identification of liver fibrosis at its earliest stages. These methods provide objective measures of diffuse liver processes and aid hepatologists in the diagnosis and management of liver disease.
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Out of balance--systemic iron homeostasis in iron-related disorders. Nutrients 2013; 5:3034-61. [PMID: 23917168 PMCID: PMC3775241 DOI: 10.3390/nu5083034] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 07/16/2013] [Accepted: 07/19/2013] [Indexed: 02/06/2023] Open
Abstract
Iron is an essential element in our daily diet. Most iron is required for the de novo synthesis of red blood cells, where it plays a critical role in oxygen binding to hemoglobin. Thus, iron deficiency causes anemia, a major public health burden worldwide. On the other extreme, iron accumulation in critical organs such as liver, heart, and pancreas causes organ dysfunction due to the generation of oxidative stress. Therefore, systemic iron levels must be tightly balanced. Here we focus on the regulatory role of the hepcidin/ferroportin circuitry as the major regulator of systemic iron homeostasis. We discuss how regulatory cues (e.g., iron, inflammation, or hypoxia) affect the hepcidin response and how impairment of the hepcidin/ferroportin regulatory system causes disorders of iron metabolism.
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Abstract
A decade ago, hepcidin, an antimicrobial peptide with iron-regulatory properties, was discovered and proposed as playing a significant role in the pathogenesis of anemia of chronic disease. Subsequent studies have demonstrated that hepcidin is the keystone of the linked systems of iron balance and iron transport in health and in disease. The definition of the role of hepcidin and its regulation has permitted the mechanisms of disorders of iron homeostasis to be understood at a molecular level. Future studies may identify roles for hepcidin or hepcidin-related molecules in diagnosis and therapy.
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Affiliation(s)
- Robert T Means
- Department of Internal Medicine, Veterans Affairs Medical Center, Lexington, KY, USA.
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van der Harst P, Zhang W, Mateo Leach I, Rendon A, Verweij N, Sehmi J, Paul DS, Elling U, Allayee H, Li X, Radhakrishnan A, Tan ST, Voss K, Weichenberger CX, Albers CA, Al-Hussani A, Asselbergs FW, Ciullo M, Danjou F, Dina C, Esko T, Evans DM, Franke L, Gögele M, Hartiala J, Hersch M, Holm H, Hottenga JJ, Kanoni S, Kleber ME, Lagou V, Langenberg C, Lopez LM, Lyytikäinen LP, Melander O, Murgia F, Nolte IM, O'Reilly PF, Padmanabhan S, Parsa A, Pirastu N, Porcu E, Portas L, Prokopenko I, Ried JS, Shin SY, Tang CS, Teumer A, Traglia M, Ulivi S, Westra HJ, Yang J, Zhao JH, Anni F, Abdellaoui A, Attwood A, Balkau B, Bandinelli S, Bastardot F, Benyamin B, Boehm BO, Cookson WO, Das D, de Bakker PIW, de Boer RA, de Geus EJC, de Moor MH, Dimitriou M, Domingues FS, Döring A, Engström G, Eyjolfsson GI, Ferrucci L, Fischer K, Galanello R, Garner SF, Genser B, Gibson QD, Girotto G, Gudbjartsson DF, Harris SE, Hartikainen AL, Hastie CE, Hedblad B, Illig T, Jolley J, Kähönen M, Kema IP, Kemp JP, Liang L, Lloyd-Jones H, Loos RJF, Meacham S, Medland SE, Meisinger C, Memari Y, Mihailov E, Miller K, Moffatt MF, Nauck M, Novatchkova M, Nutile T, Olafsson I, Onundarson PT, Parracciani D, Penninx BW, Perseu L, Piga A, Pistis G, Pouta A, Puc U, Raitakari O, Ring SM, Robino A, Ruggiero D, Ruokonen A, Saint-Pierre A, Sala C, Salumets A, Sambrook J, Schepers H, Schmidt CO, Silljé HHW, Sladek R, Smit JH, Starr JM, Stephens J, Sulem P, Tanaka T, Thorsteinsdottir U, Tragante V, van Gilst WH, van Pelt LJ, van Veldhuisen DJ, Völker U, Whitfield JB, Willemsen G, Winkelmann BR, Wirnsberger G, Algra A, Cucca F, d'Adamo AP, Danesh J, Deary IJ, Dominiczak AF, Elliott P, Fortina P, Froguel P, Gasparini P, Greinacher A, Hazen SL, Jarvelin MR, Khaw KT, Lehtimäki T, Maerz W, Martin NG, Metspalu A, Mitchell BD, Montgomery GW, Moore C, Navis G, Pirastu M, Pramstaller PP, Ramirez-Solis R, Schadt E, Scott J, Shuldiner AR, Smith GD, Smith JG, Snieder H, Sorice R, Spector TD, Stefansson K, Stumvoll M, Tang WHW, Toniolo D, Tönjes A, Visscher PM, Vollenweider P, Wareham NJ, Wolffenbuttel BHR, Boomsma DI, Beckmann JS, Dedoussis GV, Deloukas P, Ferreira MA, Sanna S, Uda M, Hicks AA, Penninger JM, Gieger C, Kooner JS, Ouwehand WH, Soranzo N, Chambers JC. Seventy-five genetic loci influencing the human red blood cell. Nature 2012; 492:369-75. [PMID: 23222517 PMCID: PMC3623669 DOI: 10.1038/nature11677] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 10/15/2012] [Indexed: 11/09/2022]
Abstract
Anaemia is a chief determinant of global ill health, contributing to cognitive impairment, growth retardation and impaired physical capacity. To understand further the genetic factors influencing red blood cells, we carried out a genome-wide association study of haemoglobin concentration and related parameters in up to 135,367 individuals. Here we identify 75 independent genetic loci associated with one or more red blood cell phenotypes at P < 10(-8), which together explain 4-9% of the phenotypic variance per trait. Using expression quantitative trait loci and bioinformatic strategies, we identify 121 candidate genes enriched in functions relevant to red blood cell biology. The candidate genes are expressed preferentially in red blood cell precursors, and 43 have haematopoietic phenotypes in Mus musculus or Drosophila melanogaster. Through open-chromatin and coding-variant analyses we identify potential causal genetic variants at 41 loci. Our findings provide extensive new insights into genetic mechanisms and biological pathways controlling red blood cell formation and function.
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Affiliation(s)
- Pim van der Harst
- Department of Cardiology, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands.
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Iron homeostasis and its disorders in mice and men: potential lessons for rhinos. J Zoo Wildl Med 2012; 43:S19-26. [PMID: 23156702 DOI: 10.1638/2011-0158.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During the last decade, there have been remarkable advances in the understanding of iron homeostasis and its disorders. This review summarizes our presentation at the International Workshop on Iron Storage Disease in Black Rhinos that was held in Orlando, Florida, USA, from 23 to 26 February 2011, and it is directed to veterinarians and nutritional experts who treat rhinoceroses. This review summarizes the current knowledge in humans and mice regarding the physiology and molecular basis of iron overload, and it explores how it can be applied to the problem of iron overload in captive rhino populations.
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Zhang Y, Li MM, Zeng F, Yao C, Wang KP. Study to establish the role of JAK2 and SMAD1/5/8 pathways in the inhibition of hepcidin by polysaccharides from Angelica sinensis. JOURNAL OF ETHNOPHARMACOLOGY 2012; 144:433-440. [PMID: 23036813 DOI: 10.1016/j.jep.2012.09.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 09/20/2012] [Accepted: 09/25/2012] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Angelica sinensis polysaccharide (ASP) is one of the major active ingredients in Angelica sinensis (Oliv.) Diels. This traditional Chinese medicine has been used for thousands of years for treating gynecological diseases. AIM OF THE STUDY Previous studies have suggested that ASP from the roots of Angelica sinensis (Oliv.) Diels suppresses hepcidin expression, but the underlying molecular mechanisms are not known. The present study was designed to establish the role of the janus-kinases 2 (JAK2) and son of mothers against decapentaplegic 1/5/8 (SMAD1/5/8) pathways in the inhibition of hepcidin by polysaccharides from Angelica sinensis in normal rats. MATERIALS AND METHODS ASP was administered orally (0.3, 0.6 and 1.2g/kg body weight) to male Sprague-Dawley rats every day for 20 days. Intraperitoneal injections of recombinant human erythropoietin (rhEPO; 800 and 2000U/kg body weight) were given to the positive control group every day for 3 days. After administration, hepcidin levels, blood parameters, serum iron status and non-heme iron concentrations in the liver were examined. Western blot analyses were used to investigate the expression of five relevant signaling proteins in the liver. RESULTS RhEPO injection significantly stimulated erythropoiesis and expression of the serum transferrin receptor (sTfR), and decreased serum iron status and non-heme iron concentrations in the liver. However, blood parameters barely changed in the ASP groups. sTfR, serum iron, and liver iron levels altered only in the ASP high-dose group (1.2g/kg body weight). rhEPO and ASP significantly reduced hepcidin expression by inhibiting the expression of phospho-SMAD1/5/8 and JAK2 in the liver, but not through transmembrane protease serine 6 (TMPRSS6) and extracellular signal-regulated kinase 1/2 (ERK1/2). CONCLUSIONS These data suggested that ASP can interrupt the JAK2 and SMAD1/5/8 pathways, which eventually results in lower expression of hepcidin.
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Affiliation(s)
- Yu Zhang
- Union Hospital of Huazhong University of Science and Technology, Department of Pharmacy, No. 1227 Jiefang Road, Wuhan, China
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Ruiz JC, Walker SD, Anderson SA, Eisenstein RS, Bruick RK. F-box and leucine-rich repeat protein 5 (FBXL5) is required for maintenance of cellular and systemic iron homeostasis. J Biol Chem 2012; 288:552-60. [PMID: 23135277 PMCID: PMC3537052 DOI: 10.1074/jbc.m112.426171] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Maintenance of cellular iron homeostasis requires post-transcriptional regulation of iron metabolism genes by iron regulatory protein 2 (IRP2). The hemerythrin-like domain of F-box and leucine-rich repeat protein 5 (FBXL5), an E3 ubiquitin ligase subunit, senses iron and oxygen availability and facilitates IRP2 degradation in iron replete cells. Disruption of the ubiquitously expressed murine Fbxl5 gene results in a failure to sense increased cellular iron availability, accompanied by constitutive IRP2 accumulation and misexpression of IRP2 target genes. FBXL5-null mice die during embryogenesis, although viability is restored by simultaneous deletion of the IRP2, but not IRP1, gene. Mice containing a single functional Fbxl5 allele behave like their wild type littermates when fed an iron-sufficient diet. However, unlike wild type mice that manifest decreased hematocrit and hemoglobin levels when fed a low-iron diet, Fbxl5 heterozygotes maintain normal hematologic values due to increased iron absorption. The responsiveness of IRP2 to low iron is specifically enhanced in the duodena of the heterozygotes and is accompanied by increased expression of the divalent metal transporter-1. These results confirm the role of FBXL5 in the in vivo maintenance of cellular and systemic iron homeostasis and reveal a privileged role for the intestine in their regulation by virtue of its unique FBXL5 iron sensitivity.
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Affiliation(s)
- Julio C Ruiz
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9038, USA
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Camaschella C. How I manage patients with atypical microcytic anaemia. Br J Haematol 2012; 160:12-24. [PMID: 23057559 DOI: 10.1111/bjh.12081] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 09/07/2012] [Indexed: 01/19/2023]
Abstract
Microcytic hypochromic anaemias are a result of defective iron handling by erythroblasts that decrease the haemoglobin content per red cell. Recent advances in our knowledge of iron metabolism and its homeostasis have led to the discovery of novel inherited anaemias that need to be distinguished from common iron deficiency or other causes of microcytosis. These atypical microcytic anaemias can be classified as: (i) defects of intestinal iron absorption (ii) disorders of the transferrin receptor cycle that impair erythroblast iron uptake (iii) defects of mitochondrial iron utilization for haem or iron sulphur cluster synthesis and (iv) defects of iron recycling. A careful patient history and evaluation of laboratory tests may enable these rare conditions to be distinguished from the more common iron deficiency anaemia. Molecular studies allow distinction of the different types, a prerequisite for differentiated therapy.
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Affiliation(s)
- Clara Camaschella
- Vita-Salute University and San Raffaele Scientific Institute, Via Olgettina 60, Milan, Italy.
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31
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Genetic modification of iron metabolism in mice affects the gut microbiota. Biometals 2012; 25:883-92. [DOI: 10.1007/s10534-012-9555-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 04/27/2012] [Indexed: 12/19/2022]
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Kloss-Brandstätter A, Erhart G, Lamina C, Meister B, Haun M, Coassin S, Seifert M, Klein-Franke A, Paulweber B, Kedenko L, Kollerits B, Swinkels DW, Vermeulen SH, Galesloot TE, Kronenberg F, Weiss G. Candidate gene sequencing of SLC11A2 and TMPRSS6 in a family with severe anaemia: common SNPs, rare haplotypes, no causative mutation. PLoS One 2012; 7:e35015. [PMID: 22509377 PMCID: PMC3324414 DOI: 10.1371/journal.pone.0035015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 03/08/2012] [Indexed: 12/26/2022] Open
Abstract
Background Iron-refractory iron deficiency anaemia (IRIDA) is a rare disorder which was linked to mutations in two genes (SLC11A2 and TMPRSS6). Common polymorphisms within these genes were associated with serum iron levels. We identified a family of Serbian origin with asymptomatic non-consanguineous parents with three of four children presenting with IRIDA not responding to oral but to intravenous iron supplementation. After excluding all known causes responsible for iron deficiency anaemia we searched for mutations in SLC11A2 and TMPRSS6 that could explain the severe anaemia in these children. Methodology/Results We sequenced the exons and exon–intron boundaries of SLC11A2 and TMPRSS6 in all six family members. Thereby, we found seven known and fairly common SNPs, but no new mutation. We then genotyped these seven SNPs in the population-based SAPHIR study (n = 1,726) and performed genetic association analysis on iron and ferritin levels. Only two SNPs, which were top-hits from recent GWAS on iron and ferritin, exhibited an effect on iron and ferritin levels in SAPHIR. Six SAPHIR participants carrying the same TMPRSS6 genotypes and haplotype-pairs as one anaemic son showed lower ferritin and iron levels than the average. One individual exhibiting the joint SLC11A2/TMPRSS6 profile of the anaemic son had iron and ferritin levels lying below the 5th percentile of the population's iron and ferritin level distribution. We then checked the genotype constellations in the Nijmegen Biomedical Study (n = 1,832), but the profile of the anaemic son did not occur in this population. Conclusions We cannot exclude a gene-gene interaction between SLC11A2 and TMPRSS6, but we can also not confirm it. As in this case candidate gene sequencing did not reveal causative rare mutations, the samples will be subjected to whole exome sequencing.
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Affiliation(s)
- Anita Kloss-Brandstätter
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Gertraud Erhart
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Claudia Lamina
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Bernhard Meister
- Department of Paediatrics II, Innsbruck Medical University, Innsbruck, Austria
| | - Margot Haun
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Stefan Coassin
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Markus Seifert
- Department of Internal Medicine I, Clinical Immunology and Infectious Diseases, Innsbruck Medical University, Innsbruck, Austria
| | | | - Bernhard Paulweber
- First Department of Internal Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Lyudmyla Kedenko
- First Department of Internal Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kollerits
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Dorine W. Swinkels
- Department of Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic Diseases, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Sita H. Vermeulen
- Department of Epidemiology, Biostatistics and HTA, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Tessel E. Galesloot
- Department of Epidemiology, Biostatistics and HTA, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Florian Kronenberg
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
- * E-mail: (FK); (GW)
| | - Günter Weiss
- Department of Internal Medicine I, Clinical Immunology and Infectious Diseases, Innsbruck Medical University, Innsbruck, Austria
- * E-mail: (FK); (GW)
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Wysokinski D, Zaras M, Dorecka M, Waszczyk M, Szaflik J, Blasiak J, Szaflik JP. An association between environmental factors and the IVS4+44C>A polymorphism of the DMT1 gene in age-related macular degeneration. Graefes Arch Clin Exp Ophthalmol 2012; 250:1057-65. [PMID: 22371024 PMCID: PMC3382657 DOI: 10.1007/s00417-012-1966-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 02/01/2012] [Accepted: 02/03/2012] [Indexed: 12/14/2022] Open
Abstract
Background Age-related macular degeneration (AMD) is an ocular disease affecting macula — the central part of the retina, resulting in the degeneration of photoreceptors and retinal epithelium and causing severe central vision impairment. The pathophysiology of the disease is not completely known, but a significant role is attributed to genetic factors. The contribution of oxidative stress in AMD as a trigger of the degenerative process is well-established. Iron ions may act as a source of reactive oxygen species; therefore, maintaining iron homeostasis is important for redox balance in the organism. Diversity in iron homeostasis genes may counterpart in unbalanced redox state, and thus be involved in AMD pathophysiology. Methods In this work, we searched for an association between some single nucleotide polymorphisms in the divalent metal transporter 1 (DMT1) gene intronic IVS4+44C>A (rs224589) and 3’-UTR c.2044T>C (rs2285230) and environmental factors and AMD. Genotyping was performed using the PCR-RFLP method. DNA was obtained from 436 AMD patients and 168 controls. Results We did not find any association between the genotypes of the two polymorphisms and AMD occurrence. However, we observed that AMD patients living in a rural environment and having the CC genotype of the IVS4+44C>A polymorphism had an increased risk of AMD, while individuals with the CA genotype or the A allele had a decreased risk of the disease. Moreover, in male AMD patients the C allele increased the risk of the disease, while the AA genotype decreased it. Conclusions These results suggest that the VS4+44C>A polymorphism of the DMT1 gene may interact with place of living and gender to modulate the risk of AMD.
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Affiliation(s)
- Daniel Wysokinski
- Department of Molecular Genetics, University of Lodz, Pomorska 141/143, Lodz, Poland
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Iron disorders of genetic origin: a changing world. Trends Mol Med 2011; 17:707-13. [DOI: 10.1016/j.molmed.2011.07.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 07/13/2011] [Accepted: 07/20/2011] [Indexed: 12/15/2022]
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Guggenbuhl P, Brissot P, Loréal O. Haemochromatosis: The bone and the joint. Best Pract Res Clin Rheumatol 2011; 25:649-64. [DOI: 10.1016/j.berh.2011.10.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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