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Padmanabhan N, Menelaou K, Gao J, Anderson A, Blake GET, Li T, Daw BN, Watson ED. Abnormal folate metabolism causes age-, sex- and parent-of-origin-specific haematological defects in mice. J Physiol 2018; 596:4341-4360. [PMID: 30024025 PMCID: PMC6138292 DOI: 10.1113/jp276419] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/27/2018] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS Folate (folic acid) deficiency and mutations in folate-related genes in humans result in megaloblastic anaemia. Folate metabolism, which requires the enzyme methionine synthase reductase (MTRR), is necessary for DNA synthesis and the transmission of one-carbon methyl groups for cellular methylation. In this study, we show that the hypomorphic Mtrrgt/gt mutation in mice results in late-onset and sex-specific blood defects, including macrocytic anaemia, extramedullary haematopoiesis and lymphopenia. Notably, when either parent carries an Mtrrgt allele, blood phenotypes result in their genetically wildtype adult daughters, the effects of which are parent specific. Our data establish a new model for studying the mechanism of folate metabolism in macrocytic anaemia aetiology and suggest that assessing parental folate status might be important when diagnosing adult patients with unexplained anaemia. ABSTRACT The importance of the vitamin folate (also known as folic acid) in erythrocyte formation, maturation and/or longevity is apparent since folate deficiency in humans causes megaloblastic anaemia. Megaloblastic anaemia is a type of macrocytic anaemia whereby erythrocytes are enlarged and fewer in number. Folate metabolism is required for thymidine synthesis and one-carbon metabolism, though its specific role in erythropoiesis is not well understood. Methionine synthase reductase (MTRR) is a key enzyme necessary for the progression of folate metabolism since knocking down the Mtrr gene in mice results in hyperhomocysteinaemia and global DNA hypomethylation. We demonstrate here that abnormal folate metabolism in mice caused by Mtrrgt/gt homozygosity leads to haematopoietic phenotypes that are sex and age dependent. Specifically, Mtrrgt/gt female mice displayed macrocytic anaemia, which might be due to defective erythroid differentiation at the exclusion of haemolysis. This was associated with increased renal Epo mRNA expression, hypercellular bone marrow, and splenic extramedullary haematopoiesis. In contrast, the male response differed since Mtrrgt/gt male mice were not anaemic but did display erythrocytic macrocytosis and lymphopenia. Regardless of sex, these phenotypes were late onset. Remarkably, we also show that when either parent carries an Mtrrgt allele, a haematological defect results in their adult wildtype daughters. However, the specific phenotype was dependent upon the sex of the parent. For instance, wildtype daughters of Mtrr+/gt females displayed normocytic anaemia. In contrast, wildtype daughters of Mtrr+/gt males exhibited erythrocytic microcytosis not associated with anaemia. Therefore, abnormal folate metabolism affects adult haematopoiesis in an age-, sex- and parent-specific manner.
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Affiliation(s)
- Nisha Padmanabhan
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Centre for Trophoblast ResearchUniversity of CambridgeCambridgeUK
| | - Katerina Menelaou
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Centre for Trophoblast ResearchUniversity of CambridgeCambridgeUK
| | - Jiali Gao
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - Alexander Anderson
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Centre for Trophoblast ResearchUniversity of CambridgeCambridgeUK
| | - Georgina E. T. Blake
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Centre for Trophoblast ResearchUniversity of CambridgeCambridgeUK
| | - Tanya Li
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - B. Nuala Daw
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Centre for Trophoblast ResearchUniversity of CambridgeCambridgeUK
| | - Erica D. Watson
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
- Centre for Trophoblast ResearchUniversity of CambridgeCambridgeUK
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Laranjeira-Silva MF, Wang W, Samuel TK, Maeda FY, Michailowsky V, Hamza I, Liu Z, Andrews NW. A MFS-like plasma membrane transporter required for Leishmania virulence protects the parasites from iron toxicity. PLoS Pathog 2018; 14:e1007140. [PMID: 29906288 PMCID: PMC6021107 DOI: 10.1371/journal.ppat.1007140] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/27/2018] [Accepted: 06/05/2018] [Indexed: 01/09/2023] Open
Abstract
Iron is essential for many cellular processes, but can generate highly toxic hydroxyl radicals in the presence of oxygen. Therefore, intracellular iron accumulation must be tightly regulated, by balancing uptake with storage or export. Iron uptake in Leishmania is mediated by the coordinated action of two plasma membrane proteins, the ferric iron reductase LFR1 and the ferrous iron transporter LIT1. However, how these parasites regulate their cytosolic iron concentration to prevent toxicity remains unknown. Here we characterize Leishmania Iron Regulator 1 (LIR1), an iron responsive protein with similarity to membrane transporters of the major facilitator superfamily (MFS) and plant nodulin-like proteins. LIR1 localizes on the plasma membrane of L. amazonensis promastigotes and intracellular amastigotes. After heterologous expression in Arabidopsis thaliana, LIR1 decreases the iron content of leaves and worsens the chlorotic phenotype of plants lacking the iron importer IRT1. Consistent with a role in iron efflux, LIR1 deficiency does not affect iron uptake by L. amazonensis but significantly increases the amount of iron retained intracellularly in the parasites. LIR1 null parasites are more sensitive to iron toxicity and have drastically impaired infectivity, phenotypes that are reversed by LIR1 complementation. We conclude that LIR1 functions as a plasma membrane iron exporter with a critical role in maintaining iron homeostasis and promoting infectivity in L. amazonensis.
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Affiliation(s)
| | - Wanpeng Wang
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Tamika K. Samuel
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Fernando Y. Maeda
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Vladimir Michailowsky
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
- Faculdade de Medicina, Setor Parasitologia, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Iqbal Hamza
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Zhongchi Liu
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Norma W. Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
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Iron economy in Naegleria gruberi reflects its metabolic flexibility. Int J Parasitol 2018; 48:719-727. [PMID: 29738737 DOI: 10.1016/j.ijpara.2018.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 11/24/2022]
Abstract
Naegleria gruberi is a free-living amoeba, closely related to the human pathogen Naegleria fowleri, the causative agent of the deadly human disease primary amoebic meningoencephalitis. Herein, we investigated the effect of iron limitation on different aspects of N. gruberi metabolism. Iron metabolism is among the most conserved pathways found in all eukaryotes. It includes the delivery, storage and utilisation of iron in many cell processes. Nevertheless, most of the iron metabolism pathways of N. gruberi are still not characterised, even though iron balance within the cell is crucial. We found a single homolog of ferritin in the N. gruberi genome and showed its localisation in the mitochondrion. Using comparative mass spectrometry, we identified 229 upregulated and 184 down-regulated proteins under iron-limited conditions. The most down-regulated protein under iron-limited conditions was hemerythrin, and a similar effect on the expression of hemerythrin was found in N. fowleri. Among the other down-regulated proteins were [FeFe]-hydrogenase and its maturase HydG and several heme-containing proteins. The activities of [FeFe]-hydrogenase, as well as alcohol dehydrogenase, were also decreased by iron deficiency. Our results indicate that N. gruberi is able to rearrange its metabolism according to iron availability, prioritising mitochondrial pathways. We hypothesise that the mitochondrion is the center for iron homeostasis in N. gruberi, with mitochondrially localised ferritin as a potential key component of this process.
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Ferritin from the haemolymph of adult ants: an extraction method for characterization and a ferromagnetic study. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:641-653. [DOI: 10.1007/s00249-018-1293-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/05/2018] [Accepted: 03/13/2018] [Indexed: 01/03/2023]
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55
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Guerrero-Hue M, Rubio-Navarro A, Sevillano Á, Yuste C, Gutiérrez E, Palomino-Antolín A, Román E, Praga M, Egido J, Moreno JA. Efectos adversos de la acumulación renal de hemoproteínas. Nuevas herramientas terapéuticas. Nefrologia 2018; 38:13-26. [DOI: 10.1016/j.nefro.2017.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/21/2017] [Accepted: 05/16/2017] [Indexed: 12/18/2022] Open
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Bourassa D, Gleber SC, Vogt S, Shin CH, Fahrni CJ. MicroXRF tomographic visualization of zinc and iron in the zebrafish embryo at the onset of the hatching period. Metallomics 2017; 8:1122-1130. [PMID: 27531414 DOI: 10.1039/c6mt00073h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Transition metals such as zinc, copper, and iron play key roles in cellular proliferation, cell differentiation, growth, and development. Over the past decade, advances in synchrotron X-ray fluorescence instrumentation presented new opportunities for the three-dimensional mapping of trace metal distributions within intact specimens. Taking advantage of microXRF tomography, we visualized the 3D distribution of zinc and iron in a zebrafish embryo at the onset of the hatching period. The reconstructed volumetric data revealed distinct differences in the elemental distributions, with zinc predominantly localized to the yolk and yolk extension, and iron to various regions of the brain as well as the myotome extending along the dorsal side of the embryo. The data set complements an earlier tomographic study of an embryo at the pharyngula stage (24 hpf), thus offering new insights into the trace metal distribution at key stages of embryonic development.
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Affiliation(s)
- Daisy Bourassa
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA 30332, USA.
| | - Sophie-Charlotte Gleber
- Advanced Photon Source, X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Stefan Vogt
- Advanced Photon Source, X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Chong Hyun Shin
- School of Biological Sciences and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA
| | - Christoph J Fahrni
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA 30332, USA.
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Gryzik M, Srivastava A, Longhi G, Bertuzzi M, Gianoncelli A, Carmona F, Poli M, Arosio P. Expression and characterization of the ferritin binding domain of Nuclear Receptor Coactivator-4 (NCOA4). Biochim Biophys Acta Gen Subj 2017; 1861:2710-2716. [DOI: 10.1016/j.bbagen.2017.07.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/22/2017] [Accepted: 07/24/2017] [Indexed: 11/24/2022]
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58
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Lakhal-Littleton S, Robbins PA. The interplay between iron and oxygen homeostasis with a particular focus on the heart. J Appl Physiol (1985) 2017; 123:967-973. [PMID: 28775066 DOI: 10.1152/japplphysiol.00237.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 07/10/2017] [Accepted: 07/29/2017] [Indexed: 12/11/2022] Open
Abstract
Iron is subject to tight homeostatic control in mammals. At the systemic level, iron homeostasis is controlled by the liver-derived hormone hepcidin acting on its target ferroportin in the gut, spleen, and liver, which form the sites of iron uptake, recycling, and storage, respectively. At the cellular level, iron homeostasis is dependent on the iron regulatory proteins IRP1/IRP2. Unique chemical properties of iron underpin its importance in biochemical reactions involving oxygen. As such, it is not surprising that there are reciprocal regulatory links between iron and oxygen homeostasis, operating both at the systemic and cellular levels. Hypoxia activates the IRP pathway, and in addition suppresses liver hepcidin through endocrine factors that have yet to be fully elucidated. This review summarizes current knowledge on the interplay between oxygen and iron homeostasis and describes recent insights gained into this interaction in the context of the heart. These include the recognition that the hepcidin/ferroportin axis plays a vital role in the regulation of intracellular iron homeostasis as well as regulating systemic iron availability. As is the case for other aspects of iron homeostasis, hypoxia significantly modulates the function of the hepcidin/ferroportin pathway in the heart. Key areas still to understand are the interactions between cardiac iron and diseases of the heart where hypoxia is a recognized component.
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Affiliation(s)
- Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter Alistair Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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59
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The Construction and Characterization of Mitochondrial Ferritin Overexpressing Mice. Int J Mol Sci 2017; 18:ijms18071518. [PMID: 28703745 PMCID: PMC5536008 DOI: 10.3390/ijms18071518] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/06/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial ferritin (FtMt) is a H-ferritin-like protein which localizes to mitochondria. Previous studies have shown that this protein can protect mitochondria from iron-induced oxidative damage, while FtMt overexpression in cultured cells decreases cytosolic iron availability and protects against oxidative damage. To investigate the in vivo role of FtMt, we established FtMt overexpressing mice by pro-nucleus microinjection and examined the characteristics of the animals. We first confirmed that the protein levels of FtMt in the transgenic mice were increased compared to wild-type mice. Interestingly, we found no significant differences in the body weights or organ to body weight ratios between wild type and transgenic mice. To determine the effects of FtMt overexpression on baseline murine iron metabolism and hematological indices, we measured serum, heart, liver, spleen, kidney, testis, and brain iron concentrations, liver hepcidin expression and red blood cell parameters. There were no significant differences between wild type and transgenic mice. In conclusion, our results suggest that FtMt overexpressing mice have no significant defects and the overexpression of FtMt does not affect the regulation of iron metabolism significantly in transgenic mice.
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60
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Martins AC, Almeida JI, Lima IS, Kapitão AS, Gozzelino R. Iron Metabolism and the Inflammatory Response. IUBMB Life 2017; 69:442-450. [PMID: 28474474 DOI: 10.1002/iub.1635] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/06/2017] [Indexed: 12/19/2022]
Abstract
Iron (Fe) is essential to almost all organisms, as required by cells to satisfy metabolic needs and accomplish specialized functions. Its ability to exchange electrons between different substrates, however, renders it potentially toxic. Fine tune-mechanisms are necessary to maintain Fe homeostasis and, as such, to prevent its participation into the Fenton reaction and generation of oxidative stress. These are particularly important in the context of inflammation/infection, where restricting Fe availability to invading pathogens is one, if not, the main host defense strategy against microbial growth. The ability of Fe to modulate several aspects of the immune response is associated with a number of "costs" and "benefits", some of which have been described in this review. © 2017 IUBMB Life, 69(6):442-450, 2017.
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Affiliation(s)
- Ana C Martins
- Chronic Diseases Research Center (CEDOC)/NOVA Medical School, NOVA University of Lisbon, Portugal
| | - Joana I Almeida
- Chronic Diseases Research Center (CEDOC)/NOVA Medical School, NOVA University of Lisbon, Portugal
| | - Illyane S Lima
- Chronic Diseases Research Center (CEDOC)/NOVA Medical School, NOVA University of Lisbon, Portugal
| | - Antonino S Kapitão
- Chronic Diseases Research Center (CEDOC)/NOVA Medical School, NOVA University of Lisbon, Portugal
| | - Raffaella Gozzelino
- Chronic Diseases Research Center (CEDOC)/NOVA Medical School, NOVA University of Lisbon, Portugal
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61
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Arosio P, Elia L, Poli M. Ferritin, cellular iron storage and regulation. IUBMB Life 2017; 69:414-422. [DOI: 10.1002/iub.1621] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 02/28/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Paolo Arosio
- Laboratory of Molecular Biology, Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
| | - Leonardo Elia
- Laboratory of Molecular Biology, Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
- Humanitas Clinical and Research CenterRozzano MI Italy
| | - Maura Poli
- Laboratory of Molecular Biology, Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
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Abstract
Iron is an essential element for numerous fundamental biologic processes, but excess iron is toxic. Abnormalities in systemic iron balance are common in patients with chronic kidney disease and iron administration is a mainstay of anemia management in many patients. This review provides an overview of the essential role of iron in biology, the regulation of systemic and cellular iron homeostasis, how imbalances in iron homeostasis contribute to disease, and the implications for chronic kidney disease patients.
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Affiliation(s)
- Som Dev
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jodie L Babitt
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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63
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Study of ferritin self-assembly and heteropolymer formation by the use of Fluorescence Resonance Energy Transfer (FRET) technology. Biochim Biophys Acta Gen Subj 2017; 1861:522-532. [DOI: 10.1016/j.bbagen.2016.12.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 12/31/2022]
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64
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Garton T, Keep RF, Hua Y, Xi G. Brain iron overload following intracranial haemorrhage. Stroke Vasc Neurol 2016; 1:172-184. [PMID: 28959481 PMCID: PMC5435218 DOI: 10.1136/svn-2016-000042] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/01/2016] [Accepted: 11/02/2016] [Indexed: 12/15/2022] Open
Abstract
Intracranial haemorrhages, including intracerebral haemorrhage (ICH), intraventricular haemorrhage (IVH) and subarachnoid haemorrhage (SAH), are leading causes of morbidity and mortality worldwide. In addition, haemorrhage contributes to tissue damage in traumatic brain injury (TBI). To date, efforts to treat the long-term consequences of cerebral haemorrhage have been unsatisfactory. Incident rates and mortality have not showed significant improvement in recent years. In terms of secondary damage following haemorrhage, it is becoming increasingly apparent that blood components are of integral importance, with haemoglobin-derived iron playing a major role. However, the damage caused by iron is complex and varied, and therefore, increased investigation into the mechanisms by which iron causes brain injury is required. As ICH, IVH, SAH and TBI are related, this review will discuss the role of iron in each, so that similarities in injury pathologies can be more easily identified. It summarises important components of normal brain iron homeostasis and analyses the existing evidence on iron-related brain injury mechanisms. It further discusses treatment options of particular promise.
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Affiliation(s)
- Thomas Garton
- Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Ya Hua
- Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Guohua Xi
- Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA
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65
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Eid R, Arab NTT, Greenwood MT. Iron mediated toxicity and programmed cell death: A review and a re-examination of existing paradigms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:399-430. [PMID: 27939167 DOI: 10.1016/j.bbamcr.2016.12.002] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/08/2016] [Accepted: 12/04/2016] [Indexed: 12/11/2022]
Abstract
Iron is an essential micronutrient that is problematic for biological systems since it is toxic as it generates free radicals by interconverting between ferrous (Fe2+) and ferric (Fe3+) forms. Additionally, even though iron is abundant, it is largely insoluble so cells must treat biologically available iron as a valuable commodity. Thus elaborate mechanisms have evolved to absorb, re-cycle and store iron while minimizing toxicity. Focusing on rarely encountered situations, most of the existing literature suggests that iron toxicity is common. A more nuanced examination clearly demonstrates that existing regulatory processes are more than adequate to limit the toxicity of iron even in response to iron overload. Only under pathological or artificially harsh situations of exposure to excess iron does it become problematic. Here we review iron metabolism and its toxicity as well as the literature demonstrating that intracellular iron is not toxic but a stress responsive programmed cell death-inducing second messenger.
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Affiliation(s)
- Rawan Eid
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, Canada
| | - Nagla T T Arab
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, Canada
| | - Michael T Greenwood
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, Canada.
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66
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Chandramouli B, Bernacchioni C, Di Maio D, Turano P, Brancato G. Electrostatic and Structural Bases of Fe2+ Translocation through Ferritin Channels. J Biol Chem 2016; 291:25617-25628. [PMID: 27756844 DOI: 10.1074/jbc.m116.748046] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/03/2016] [Indexed: 01/14/2023] Open
Abstract
Ferritin molecular cages are marvelous 24-mer supramolecular architectures that enable massive iron storage (>2000 iron atoms) within their inner cavity. This cavity is connected to the outer environment by two channels at C3 and C4 symmetry axes of the assembly. Ferritins can also be exploited as carriers for in vivo imaging and therapeutic applications, owing to their capability to effectively protect synthetic non-endogenous agents within the cage cavity and deliver them to targeted tissue cells without stimulating adverse immune responses. Recently, X-ray crystal structures of Fe2+-loaded ferritins provided important information on the pathways followed by iron ions toward the ferritin cavity and the catalytic centers within the protein. However, the specific mechanisms enabling Fe2+ uptake through wild-type and mutant ferritin channels is largely unknown. To shed light on this question, we report extensive molecular dynamics simulations, site-directed mutagenesis, and kinetic measurements that characterize the transport properties and translocation mechanism of Fe2+ through the two ferritin channels, using the wild-type bullfrog Rana catesbeiana H' protein and some of its variants as case studies. We describe the structural features that determine Fe2+ translocation with atomistic detail, and we propose a putative mechanism for Fe2+ transport through the channel at the C3 symmetry axis, which is the only iron-permeable channel in vertebrate ferritins. Our findings have important implications for understanding how ion permeation occurs, and further how it may be controlled via purposely engineered channels for novel biomedical applications based on ferritin.
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Affiliation(s)
- Balasubramanian Chandramouli
- From the Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, .,the Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, and
| | - Caterina Bernacchioni
- the Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Danilo Di Maio
- From the Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa.,the Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, and
| | - Paola Turano
- the Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Giuseppe Brancato
- From the Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, .,the Istituto Nazionale di Fisica Nucleare (INFN) Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, and
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67
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Li L, Zhang L, Knez M. Comparison of two endogenous delivery agents in cancer therapy: Exosomes and ferritin. Pharmacol Res 2016; 110:1-9. [DOI: 10.1016/j.phrs.2016.05.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/07/2016] [Accepted: 05/03/2016] [Indexed: 12/21/2022]
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68
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Saenz N, Sánchez M, Gálvez N, Carmona F, Arosio P, Dominguez-Vera JM. Insights on the (Auto)Photocatalysis of Ferritin. Inorg Chem 2016; 55:6047-50. [DOI: 10.1021/acs.inorgchem.6b00547] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Natalie Saenz
- Departamento de Química Inorgánica
and Instituto de Biotecnología, Universidad de Granada, 18071 Granada, Spain
| | - Manu Sánchez
- Departamento de Química Inorgánica
and Instituto de Biotecnología, Universidad de Granada, 18071 Granada, Spain
| | - Natividad Gálvez
- Departamento de Química Inorgánica
and Instituto de Biotecnología, Universidad de Granada, 18071 Granada, Spain
| | - Fernando Carmona
- Department of Molecular
and Translational Medicine, University of Brescia, Viale Europa
11, 25123 Brescia, Italy
| | - Paolo Arosio
- Department of Molecular
and Translational Medicine, University of Brescia, Viale Europa
11, 25123 Brescia, Italy
| | - Jose M. Dominguez-Vera
- Departamento de Química Inorgánica
and Instituto de Biotecnología, Universidad de Granada, 18071 Granada, Spain
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Theil EC, Tosha T, Behera RK. Solving Biology's Iron Chemistry Problem with Ferritin Protein Nanocages. Acc Chem Res 2016; 49:784-91. [PMID: 27136423 DOI: 10.1021/ar500469e] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ferritins reversibly synthesize iron-oxy(ferrihydrite) biominerals inside large, hollow protein nanocages (10-12 nm, ∼480 000 g/mol); the iron biominerals are metabolic iron concentrates for iron protein biosyntheses. Protein cages of 12- or 24-folded ferritin subunits (4-α-helix polypeptide bundles) self-assemble, experimentally. Ferritin biomineral structures differ among animals and plants or bacteria. The basic ferritin mineral structure is ferrihydrite (Fe2O3·H2O) with either low phosphate in the highly ordered animal ferritin biominerals, Fe/PO4 ∼ 8:1, or Fe/PO4 ∼ 1:1 in the more amorphous ferritin biominerals of plants and bacteria. While different ferritin environments, plant bacterial-like plastid organelles and animal cytoplasm, might explain ferritin biomineral differences, investigation is required. Currently, the physiological significance of plant-specific and animal-specific ferritin iron minerals is unknown. The iron content of ferritin in living tissues ranges from zero in "apoferritin" to as high as ∼4500 iron atoms. Ferritin biomineralization begins with the reaction of Fe(2+) with O2 at ferritin enzyme (Fe(2+)/O oxidoreductase) sites. The product of ferritin enzyme activity, diferric oxy complexes, is also the precursor of ferritin biomineral. Concentrations of Fe(3+) equivalent to 2.0 × 10(-1) M are maintained in ferritin solutions, contrasting with the Fe(3+) Ks ∼ 10(-18) M. Iron ions move into, through, and out of ferritin protein cages in structural subdomains containing conserved amino acids. Cage subdomains include (1) ion channels for Fe(2+) entry/exit, (2) enzyme (oxidoreductase) site for coupling Fe(2+) and O yielding diferric oxy biomineral precursors, and (3) ferric oxy nucleation channels, where diferric oxy products from up to three enzyme sites interact while moving toward the central, biomineral growth cavity (12 nm diameter) where ferric oxy species, now 48-mers, grow in ferric oxy biomineral. High ferritin protein cage symmetry (3-fold and 4-fold axes) and amino acid conservation coincide with function, shown by amino acid substitution effects. 3-Fold symmetry axes control Fe(2+) entry (enzyme catalysis of Fe(2+)/O2 oxidoreduction) and Fe(2+) exit (reductive ferritin mineral dissolution); 3-fold symmetry axes influence Fe(2+)exit from dissolved mineral; bacterial ferritins diverge slightly in Fe/O2 reaction mechanisms and intracage paths of iron-oxy complexes. Biosynthesis rates of ferritin protein change with Fe(2+) and O2 concentrations, dependent on DNA-binding, and heme binding protein, Bach 1. Increased cellular O2 indirectly stabilizes ferritin DNA/Bach 1 interactions. Heme, Fe-protoporphyrin IX, decreases ferritin DNA-Bach 1 binding, causing increased ferritin mRNA biosynthesis (transcription). Direct Fe(2+) binding to ferritin mRNA decreases binding of an inhibitory protein, IRP, causing increased ferritin mRNA translation (protein biosynthesis). Newly synthesized ferritin protein consumes Fe(2+) in biomineral, decreasing Fe(2)(+) and creating a regulatory feedback loop. Ferritin without iron is "apoferritin". Iron removal from ferritin, experimentally, uses biological reductants, for example, NADH + FMN, or chemical reductants, for example, thioglycolic acid, with Fe(2+) chelators; physiological mechanism(s) are murky. Clear, however, is the necessity of ferritin for terrestrial life by conferring oxidant protection (plants, animals, and bacteria), virulence (bacteria), and embryonic survival (mammals). Future studies of ferritin structure/function and Fe(2+)/O2 chemistry will lead to new ferritin uses in medicine, nutrition, and nanochemistry.
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Affiliation(s)
- Elizabeth C. Theil
- Children’s Hospital Oakland Research Institute, Oakland, California 94609, United States
- Department of Structural
and Molecular Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7313, United States
| | - Takehiko Tosha
- Children’s Hospital Oakland Research Institute, Oakland, California 94609, United States
- Department of Structural
and Molecular Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7313, United States
| | - Rabindra K. Behera
- Children’s Hospital Oakland Research Institute, Oakland, California 94609, United States
- Department of Structural
and Molecular Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7313, United States
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Dual Role of ROS as Signal and Stress Agents: Iron Tips the Balance in favor of Toxic Effects. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:8629024. [PMID: 27006749 PMCID: PMC4783558 DOI: 10.1155/2016/8629024] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/28/2016] [Indexed: 01/01/2023]
Abstract
Iron is essential for life, while also being potentially harmful. Therefore, its level is strictly monitored and complex pathways have evolved to keep iron safely bound to transport or storage proteins, thereby maintaining homeostasis at the cellular and systemic levels. These sequestration mechanisms ensure that mildly reactive oxygen species like anion superoxide and hydrogen peroxide, which are continuously generated in cells living under aerobic conditions, keep their physiologic role in cell signaling while escaping iron-catalyzed transformation in the highly toxic hydroxyl radical. In this review, we describe the multifaceted systems regulating cellular and body iron homeostasis and discuss how altered iron balance may lead to oxidative damage in some pathophysiological settings.
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71
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Ferritin Assembly in Enterocytes of Drosophila melanogaster. Int J Mol Sci 2016; 17:27. [PMID: 26861293 PMCID: PMC4783870 DOI: 10.3390/ijms17020027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/04/2015] [Accepted: 12/11/2015] [Indexed: 11/30/2022] Open
Abstract
Ferritins are protein nanocages that accumulate inside their cavity thousands of oxidized iron atoms bound to oxygen and phosphates. Both characteristic types of eukaryotic ferritin subunits are present in secreted ferritins from insects, but here dimers between Ferritin 1 Heavy Chain Homolog (Fer1HCH) and Ferritin 2 Light Chain Homolog (Fer2LCH) are further stabilized by disulfide-bridge in the 24-subunit complex. We addressed ferritin assembly and iron loading in vivo using novel transgenic strains of Drosophila melanogaster. We concentrated on the intestine, where the ferritin induction process can be controlled experimentally by dietary iron manipulation. We showed that the expression pattern of Fer2LCH-Gal4 lines recapitulated iron-dependent endogenous expression of the ferritin subunits and used these lines to drive expression from UAS-mCherry-Fer2LCH transgenes. We found that the Gal4-mediated induction of mCherry-Fer2LCH subunits was too slow to effectively introduce them into newly formed ferritin complexes. Endogenous Fer2LCH and Fer1HCH assembled and stored excess dietary iron, instead. In contrast, when flies were genetically manipulated to co-express Fer2LCH and mCherry-Fer2LCH simultaneously, both subunits were incorporated with Fer1HCH in iron-loaded ferritin complexes. Our study provides fresh evidence that, in insects, ferritin assembly and iron loading in vivo are tightly regulated.
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72
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Bradley JM, Le Brun NE, Moore GR. Ferritins: furnishing proteins with iron. J Biol Inorg Chem 2016; 21:13-28. [PMID: 26825805 PMCID: PMC4771812 DOI: 10.1007/s00775-016-1336-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 01/06/2016] [Indexed: 12/04/2022]
Abstract
Ferritins are a superfamily of iron oxidation, storage and mineralization proteins found throughout the animal, plant, and microbial kingdoms. The majority of ferritins consist of 24 subunits that individually fold into 4-α-helix bundles and assemble in a highly symmetric manner to form an approximately spherical protein coat around a central cavity into which an iron-containing mineral can be formed. Channels through the coat at inter-subunit contact points facilitate passage of iron ions to and from the central cavity, and intrasubunit catalytic sites, called ferroxidase centers, drive Fe2+ oxidation and O2 reduction. Though the different members of the superfamily share a common structure, there is often little amino acid sequence identity between them. Even where there is a high degree of sequence identity between two ferritins there can be major differences in how the proteins handle iron. In this review we describe some of the important structural features of ferritins and their mineralized iron cores, consider how iron might be released from ferritins, and examine in detail how three selected ferritins oxidise Fe2+ to explore the mechanistic variations that exist amongst ferritins. We suggest that the mechanistic differences reflect differing evolutionary pressures on amino acid sequences, and that these differing pressures are a consequence of different primary functions for different ferritins.
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Affiliation(s)
- Justin M Bradley
- Center for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Nick E Le Brun
- Center for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Geoffrey R Moore
- Center for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
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73
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Gozzelino R, Arosio P. Iron Homeostasis in Health and Disease. Int J Mol Sci 2016; 17:E130. [PMID: 26805813 PMCID: PMC4730371 DOI: 10.3390/ijms17010130] [Citation(s) in RCA: 211] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 01/04/2016] [Accepted: 01/12/2016] [Indexed: 12/13/2022] Open
Abstract
Iron is required for the survival of most organisms, including bacteria, plants, and humans. Its homeostasis in mammals must be fine-tuned to avoid iron deficiency with a reduced oxygen transport and diminished activity of Fe-dependent enzymes, and also iron excess that may catalyze the formation of highly reactive hydroxyl radicals, oxidative stress, and programmed cell death. The advance in understanding the main players and mechanisms involved in iron regulation significantly improved since the discovery of genes responsible for hemochromatosis, the IRE/IRPs machinery, and the hepcidin-ferroportin axis. This review provides an update on the molecular mechanisms regulating cellular and systemic Fe homeostasis and their roles in pathophysiologic conditions that involve alterations of iron metabolism, and provides novel therapeutic strategies to prevent the deleterious effect of its deficiency/overload.
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Affiliation(s)
- Raffaella Gozzelino
- Inflammation and Neurodegeneration Laboratory, Chronic Diseases Research Center (CEDOC), Nova Medical School (NMS)/Faculdade de Ciências Médicas, University of Lisbon, Lisbon 1150-082, Portugal.
| | - Paolo Arosio
- Department of Molecular and Translational Medicine (DMMT), University of Brescia, Brescia 25123, Italy.
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