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Kumari S, Sinha A. Culture and transfection: Two major bottlenecks in understanding Plasmodium vivax biology. Front Microbiol 2023; 14:1144453. [PMID: 37082177 PMCID: PMC10110902 DOI: 10.3389/fmicb.2023.1144453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 02/28/2023] [Indexed: 04/07/2023] Open
Abstract
The long term in vitro culture of Plasmodium falciparum was successfully established by Trager and Jensen in 1976; however it largely remains unachieved for P. vivax. The major obstacle associated with Plasmodium vivax in vitro culture is its predilection for invading younger reticulocytes and the complex remodelling of invaded reticulocytes. There are many factors under exploration for this predilection and host–parasite interactions between merozoites and invaded reticulocytes. These include various factors related to parasite, host and environment such as compromised reticulocyte osmotic stability after invasion, abundance of iron in the reticulocytes which makes them favourable for P. vivax growth and propagation and role of a hypoxic environment in P. vivax in vitro growth. P. vivax blood stage transfection represents another major hurdle towards understanding this parasite’s complex biology. Efforts in making this parasite amenable for molecular investigation by genetic modification are limited. Newer approaches in sustaining a longer in vitro culture and thereby help advancing transfection technologies in P. vivax are urgently needed that can be explored to understand the unique biology of this parasite.
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Oleic acid magnetic iron oxide nanoparticles improve iron uptake by the modification of NADH-HCF (III) oxidoreductase without affecting cellular viability. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Shimon A, Shani O, Diskin R. Structural Basis for Receptor Selectivity by the Whitewater Arroyo Mammarenavirus. J Mol Biol 2017; 429:2825-2839. [PMID: 28736175 DOI: 10.1016/j.jmb.2017.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/11/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
Abstract
Whitewater Arroyo virus belongs to the "New World" group of mammarenaviruses that reside in rodent reservoirs and are prevalent in North and South Americas. Clades B and A/B of New World mammarenaviruses use transferrin receptor 1 (TfR1) for entry. While all of these viruses use rodent-derived TfR1 orthologs, some can also use the human-TfR1 and thereby infect humans. Although we have structural information for TfR1 recognition by pathogenic virus, we do not know what the structural differences are between the receptor-binding domains of pathogenic and non-pathogenic viruses that allow some but not all viruses to utilize the human receptor for entry. The poor understanding of the molecular determinants of mammarenavirus host range, and thus pathogenicity, is partly due to the low sequence similarity between the receptor-binding domains from these viruses and the limited available structural information that preclude the use of modeling approaches. Here we present the first crystal structure of a receptor-binding domain of a non-pathogenic clade A/B mammarenavirus. This structure reveals the magnitude of structural differences within the receptor-binding domains of TfR1-tropic viruses. Our structural and sequence analyses indicate that the same structural incompatibilities with the human receptor equally affect both pathogenic and non-pathogenic mammarenaviruses. Non-pathogenic viruses do not have specific structural elements that prevent them from using the human receptor. Instead, the ability to utilize the human receptor directly depends on the extent of weak interactions throughout the receptor-binding site that in some viruses are sufficiently strong to overcome the structural incompatibilities.
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Affiliation(s)
- Amir Shimon
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Orly Shani
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Ron Diskin
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
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4
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McLay L, Liang Y, Ly H. Comparative analysis of disease pathogenesis and molecular mechanisms of New World and Old World arenavirus infections. J Gen Virol 2014; 95:1-15. [PMID: 24068704 PMCID: PMC4093776 DOI: 10.1099/vir.0.057000-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/19/2013] [Indexed: 12/24/2022] Open
Abstract
Arenaviruses can cause fatal human haemorrhagic fever (HF) diseases for which vaccines and therapies are extremely limited. Both the New World (NW) and Old World (OW) groups of arenaviruses contain HF-causing pathogens. Although these two groups share many similarities, important differences with regard to pathogenicity and molecular mechanisms of virus infection exist. These closely related pathogens share many characteristics, including genome structure, viral assembly, natural host selection and the ability to interfere with innate immune signalling. However, members of the NW and OW viruses appear to use different receptors for cellular entry, as well as different mechanisms of virus internalization. General differences in disease signs and symptoms and pathological lesions in patients infected with either NW or OW arenaviruses are also noted and discussed herein. Whilst both the OW Lassa virus (LASV) and the NW Junin virus (JUNV) can cause disruption of the vascular endothelium, which is an important pathological feature of HF, the immune responses to these related pathogens seem to be quite distinct. Whereas LASV infection results in an overall generalized immune suppression, patients infected with JUNV seem to develop a cytokine storm. Additionally, the type of immune response required for recovery and clearance of the virus is different between NW and OW infections. These differences may be important to allow the viruses to evade host immune detection. Understanding these differences will aid the development of new vaccines and treatment strategies against deadly HF viral infections.
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MESH Headings
- Animals
- Arenaviridae Infections/immunology
- Arenaviridae Infections/pathology
- Arenaviridae Infections/virology
- Arenaviruses, New World/classification
- Arenaviruses, New World/genetics
- Arenaviruses, New World/immunology
- Arenaviruses, New World/pathogenicity
- Arenaviruses, Old World/classification
- Arenaviruses, Old World/genetics
- Arenaviruses, Old World/immunology
- Arenaviruses, Old World/pathogenicity
- Hemorrhagic Fevers, Viral/immunology
- Hemorrhagic Fevers, Viral/pathology
- Hemorrhagic Fevers, Viral/virology
- Humans
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Affiliation(s)
- Lisa McLay
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Twin Cities, MN 55108, USA
| | - Yuying Liang
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Twin Cities, MN 55108, USA
| | - Hinh Ly
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Twin Cities, MN 55108, USA
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McLay L, Ansari A, Liang Y, Ly H. Targeting virulence mechanisms for the prevention and therapy of arenaviral hemorrhagic fever. Antiviral Res 2012; 97:81-92. [PMID: 23261843 DOI: 10.1016/j.antiviral.2012.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 11/28/2012] [Accepted: 12/07/2012] [Indexed: 11/28/2022]
Abstract
A number of arenaviruses are pathogenic for humans, but they differ significantly in virulence. Lassa virus, found in West Africa, causes severe hemorrhagic fever (HF), while the other principal Old World arenavirus, lymphocytic choriomeningitis virus, causes mild illness in persons with normal immune function, and poses a threat only to immunocompromised individuals. The New World agents, including Junin, Machupo and Sabia virus, are highly pathogenic for humans. Arenaviral HF is characterized by high viremia and general immune suppression, the mechanism of which is unknown. Studies using viral reverse genetics, cell-based assays, animal models and human genome-wide association analysis have revealed potential mechanisms by which arenaviruses cause severe disease in humans. Each of the four viral gene products (GPC, L polymerase, NP, and Z matrix protein) and several host-cell factors (e.g., α-dystroglycan) are responsible for mediating viral entry, genome replication, and the inhibition of apoptosis, translation and interferon-beta (IFNβ) production. This review summarizes current knowledge of the role of each viral protein and host factor in the pathogenesis of arenaviral HF. Insights from recent studies are being exploited for the development of novel therapies.
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Affiliation(s)
- Lisa McLay
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States
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Radoshitzky SR, Kuhn JH, de Kok-Mercado F, Jahrling PB, Bavari S. Drug discovery technologies and strategies for Machupo virus and other New World arenaviruses. Expert Opin Drug Discov 2012; 7:613-32. [PMID: 22607481 PMCID: PMC3426302 DOI: 10.1517/17460441.2012.687719] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Seven arenaviruses cause viral hemorrhagic fever in humans: the Old World arenaviruses Lassa and Lujo, and the New World Clade B arenaviruses Machupo (MACV), Junín (JUNV), Guanarito (GTOV), Sabiá (SABV), and Chapare (CHPV). All of these viruses are Risk Group 4 biosafety pathogens. MACV causes human disease outbreak with high case-fatality rates. To date, at least 1,200 cases with ≈200 fatalities have been recorded. AREAS COVERED This review summarizes available systems and technologies for the identification of antivirals against MACV. Furthermore, the article summarizes animal models that have been used for the in vivo evaluation of novel inhibitors. The article highlights present treatments for arenaviral diseases and provides an overview of efficacious small molecules and other therapeutics reported to date. Finally, the article summarizes strategies to identify novel inhibitors for anti-arenaviral therapy. EXPERT OPINION New high-throughput approaches to quantitate infection rates of arenaviruses, as well as viruses modified to carry reporter genes, will accelerate compound screens and drug discovery efforts. RNAi, gene expression profiling and proteomics studies will identify host targets for therapeutic intervention. New discoveries in the cell entry mechanism of MACV and other arenaviruses as well as extensive structural studies of arenaviral L and NP could facilitate the rational design of antivirals effective against all pathogenic New World arenaviruses.
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Affiliation(s)
- Sheli R. Radoshitzky
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA
| | - Jens H. Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Fabian de Kok-Mercado
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Peter B. Jahrling
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA
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Transferrin receptor 1 in the zoonosis and pathogenesis of New World hemorrhagic fever arenaviruses. Curr Opin Microbiol 2011; 14:476-82. [PMID: 21807555 PMCID: PMC3159852 DOI: 10.1016/j.mib.2011.07.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Accepted: 07/05/2011] [Indexed: 12/21/2022]
Abstract
At least five New World arenaviruses cause severe human hemorrhagic fevers. These viruses are transmitted to humans through contact with their respective South American rodent hosts. Each uses human transferrin receptor 1 (TfR1) as its obligate receptor. Accidental similarities between human TfR1 and TfR1 orthologs of arenaviral host species enable zoonoses, whereas mice and rats are not infectable because they lack these TfR1 determinants of infection. All pathogenic New World arenaviruses bind to a common region of the apical domain of TfR1. The ability of a New World arenavirus to use human TfR1 is absolutely predictive of its ability to cause hemorrhagic fevers in humans. Nonpathogenic arenaviruses, closely related to hemorrhagic fever arenaviruses, cannot utilize human TfR1 but efficiently enter cells through TfR1 orthologs of their native rodent hosts. Mutagenesis studies suggest that minor changes in the entry glycoproteins of these nonpathogenic viruses may allow human transmission. TfR1 is upregulated as a result of iron sequestration during the acute-phase response to infection, and the severity of disease may result from amplification of viral replication during this response.
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Radoshitzky SR, Abraham J, Spiropoulou CF, Kuhn JH, Nguyen D, Li W, Nagel J, Schmidt PJ, Nunberg JH, Andrews NC, Farzan M, Choe H. Transferrin receptor 1 is a cellular receptor for New World haemorrhagic fever arenaviruses. Nature 2007; 446:92-6. [PMID: 17287727 PMCID: PMC3197705 DOI: 10.1038/nature05539] [Citation(s) in RCA: 316] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Accepted: 12/18/2006] [Indexed: 01/01/2023]
Abstract
The transferrin receptor 1 (TfR1) has been identified as the cellular receptor for four New World arenaviruses — the Junin, Machupo, Guanarito and Sabia viruses. This class of arenaviruses is important because they cause fatal haemorrhagic fevers. Treating cultured cells with an antibody against TfR1 blocks viral entry and replication. Antibodies that limit arenavirus replication without interfering with host iron metabolism may be effective in controlling outbreaks of New World haemorrhagic fever. At least five arenaviruses cause viral haemorrhagic fevers in humans. Lassa virus, an Old World arenavirus, uses the cellular receptor α-dystroglycan to infect cells1. Machupo, Guanarito, Junin and Sabia viruses are New World haemorrhagic fever viruses that do not use α-dystroglycan2. Here we show a specific, high-affinity association between transferrin receptor 1 (TfR1) and the entry glycoprotein (GP) of Machupo virus. Expression of human TfR1, but not human transferrin receptor 2, in hamster cell lines markedly enhanced the infection of viruses pseudotyped with the GP of Machupo, Guanarito and Junin viruses, but not with those of Lassa or lymphocytic choriomeningitis viruses. An anti-TfR1 antibody efficiently inhibited the replication of Machupo, Guanarito, Junin and Sabia viruses, but not that of Lassa virus. Iron depletion of culture medium enhanced, and iron supplementation decreased, the efficiency of infection by Junin and Machupo but not Lassa pseudoviruses. These data indicate that TfR1 is a cellular receptor for New World haemorrhagic fever arenaviruses.
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MESH Headings
- Antibodies/immunology
- Antibodies/pharmacology
- Antigens, CD/genetics
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Arenaviruses, New World/drug effects
- Arenaviruses, New World/metabolism
- Arenaviruses, New World/physiology
- Culture Media/chemistry
- Glycoproteins/metabolism
- Humans
- Iron/analysis
- Iron/pharmacology
- Receptors, Transferrin/antagonists & inhibitors
- Receptors, Transferrin/genetics
- Receptors, Transferrin/immunology
- Receptors, Transferrin/metabolism
- Receptors, Virus/metabolism
- Viral Envelope Proteins/metabolism
- Virus Replication/drug effects
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Affiliation(s)
- Sheli R. Radoshitzky
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts 01772, USA,
| | - Jonathan Abraham
- Pulmonary Division, Department of Pediatrics, Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA,
| | - Christina F. Spiropoulou
- Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA,
| | - Jens H. Kuhn
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts 01772, USA,
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany,
| | - Dan Nguyen
- Pulmonary Division, Department of Pediatrics, Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA,
| | - Wenhui Li
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts 01772, USA,
| | - Jane Nagel
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts 01772, USA,
| | - Paul J. Schmidt
- Division of Hematology/Oncology, Department of Pediatrics, Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA,
| | - Jack H. Nunberg
- Montana Biotechnology Center, The University of Montana, Missoula, Montana 59812, USA,
| | - Nancy C. Andrews
- Division of Hematology/Oncology, Department of Pediatrics, Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA,
| | - Michael Farzan
- Department of Microbiology and Molecular Genetics, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts 01772, USA,
| | - Hyeryun Choe
- Pulmonary Division, Department of Pediatrics, Children’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA,
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Fraenkel PG, Traver D, Donovan A, Zahrieh D, Zon LI. Ferroportin1 is required for normal iron cycling in zebrafish. J Clin Invest 2005; 115:1532-41. [PMID: 15902304 PMCID: PMC1089797 DOI: 10.1172/jci23780] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Accepted: 03/29/2005] [Indexed: 12/21/2022] Open
Abstract
Missense mutations in ferroportin1 (fpn1), an intestinal and macrophage iron exporter, have been identified between transmembrane helices 3 and 4 in the zebrafish anemia mutant weissherbst (weh(Tp85c-/-)) and in patients with type 4 hemochromatosis. To explore the effects of fpn1 mutation on blood development and iron homeostasis in the adult zebrafish, weh(Tp85c-/-) zebrafish were rescued by injection with iron dextran and studied in comparison with injected and uninjected WT zebrafish and heterozygotes. Although iron deposition was observed in all iron-injected fish, only weh(Tp85c-/-) zebrafish exhibited iron accumulation in the intestinal epithelium compatible with a block in iron export. Iron injections initially reversed the anemia. However, 8 months after iron injections were discontinued, weh(Tp85c-/-) zebrafish developed hypochromic anemia and impaired erythroid maturation despite the persistence of iron-loaded macrophages and elevated hepatic nonheme iron stores. Quantitative real-time RT-PCR revealed a significant decrease in mean hepatic transcript levels of the secreted iron-regulator hepcidin and increased intestinal expression of fpn1 in anemic weh(Tp85c-/-) adults. Injection of iron dextran into WT or mutant zebrafish embryos, however, resulted in significant increases in hepcidin expression 18 hours after injection, demonstrating that hepcidin expression in zebrafish is iron responsive and independent of fpn1's function as an iron exporter.
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Affiliation(s)
- Paula G Fraenkel
- Division of Hematology/Oncology, Children's Hospital, Karp Research Laboratories, Boston, Massachusetts 02115, USA
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10
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Suwalsky M, Martínez F, Cárdenas H, Grzyb J, Strzałka K. Iron affects the structure of cell membrane molecular models. Chem Phys Lipids 2005; 134:69-77. [PMID: 15752465 DOI: 10.1016/j.chemphyslip.2004.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 12/24/2004] [Accepted: 12/24/2004] [Indexed: 10/25/2022]
Abstract
The effects of Fe(3+) and Fe(2+) on molecular models of biomembranes were investigated. These consisted of bilayers of dimyristoylphosphatidylcholine (DMPC) and of dimyristoylphosphatidylethanolamine (DMPE), classes of phospholipids located in the outer and inner moieties of cell membranes, respectively. X-ray studies showed that very low concentrations of Fe(3+) affected DMPC organization and 10(-3)M induced a total loss of its multilamellar periodic stacking. Experiments carried out with Fe(2+) on DMPC showed weaker effects than those induced by Fe(3+) ions. Similar experiments were performed on DMPE bilayers. Fe(3+) from 10(-7)M up to 10(-4)M had practically no effect on DMPE structure. However, 10(-3)M Fe(3+) induced a deep perturbation of the multilamellar structure of DMPE. However, 10(-3)M Fe(2+) had no effect on DMPE organization practically. Differential scanning calorimetry measurements also revealed different effects of Fe(3+) and Fe(2+) on the phase transition and other thermal properties of the examined lipids. In conclusion, the results obtained indicate that iron ions interact with phospholipid bilayers perturbing their structures. These findings are consistent with the observation that iron ions change cell membrane fluidity and, therefore, affect its functions.
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Affiliation(s)
- M Suwalsky
- Department of Polymers, Faculty of Chemical Sciences, University of Concepción, Casilla 160-C, Concepción, Chile.
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11
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Abstract
This chapter describes the gene mutations, phenotypes, diagnosis and therapy of the common metabolic liver diseases in young adulthood: haemochromatosis, Wilson disease, alpha(1)-anti-trypsin deficiency and cystic fibrosis. The remarkable variability of the phenotypical expression of the mutated genotypes makes screening recommendations and the establishment of prognosis for these liver disorders in young adults problematical. The diagnosis and therapy of the young adult with metabolic liver disease is discussed, with an emphasis on maintaining quality-of-life and balancing the importance of early intervention with the stigmatization of the diagnosis of potentially life-threatening liver disease. There is a critical need for the development of biochemical markers that would predict the risk of expression of clinical phenotypes and prognosis.
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Affiliation(s)
- Mark E Mailliard
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, 982000 Nebraska Medical Center, University of Nebraska, Omaha, NE 68198-2000, USA.
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12
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Cremonesi P, Acebron A, Raja KB, Simpson RJ. Iron absorption: biochemical and molecular insights into the importance of iron species for intestinal uptake. PHARMACOLOGY & TOXICOLOGY 2002; 91:97-102. [PMID: 12427107 DOI: 10.1034/j.1600-0773.2002.910301.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Recent advances in cloning of proteins involved in intestinal iron absorption can inform design and understanding of therapeutic iron preparations. Redox chemistry of iron is particularly important in iron metabolism, both as a potential source of toxic intermediates and as an essential requirement for efficient iron transport. The initial step in iron absorption (uptake from lumen to mucosa) is particularly important and several pathways involving Fe(III) reduction or transport and Fe(II) transport have been identified. Novel genes associated with iron uptake include Dcytb, a putative iron-regulated reductase and DMT1, a Fe(II) carrier in the brush border membrane. Other mechanisms may also operate, however. We review the recent findings and apply this to understanding the absorption of Fe(III) pharmaceuticals.
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Affiliation(s)
- Piero Cremonesi
- Italfarmaco Research Center, v. Dei Lavoratori 64 Cinisello B. Milano, Italy
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13
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Blumberg RS, van de Wal Y, Claypool S, Corazza N, Dickinson B, Nieuwenhuis E, Pitman R, Spiekermann G, Zhu X, Colgan S, Lencer WI. The multiple roles of major histocompatibility complex class-I-like molecules in mucosal immune function. Acta Odontol Scand 2001; 59:139-44. [PMID: 11501882 PMCID: PMC2824335 DOI: 10.1080/000163501750266729] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The human major histocompatibility complex (MHC) on chromosome 6 encodes three classical class-I genes: human leukocyte antigens (HLA) A, B, and C. These polymorphic genes encode a 43- to 45-kDa cell surface glycoprotein that, in association with the 12-kDa beta2-microglobulin molecule, functions in the presentation of nine amino acid peptides to the T-cell receptor of CD8-bearing T lymphocytes and killer inhibitory receptors on natural killer cells. In addition to these ubiquitously expressed, polymorphic proteins, the human genome also encodes several nonclassical MHC class-I-like, or class Ib, genes that, in general, encode nonpolymorphic molecules involved in various specific immunological functions. Many of these genes, including CD1, the neonatal Fc receptor for IgG, HLA-G, HLA-E, the MHC class-I chain-related gene A, and Hfe, are prominently displayed on epithelial cells, suggesting an important role in epithelial cell biology.
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MESH Headings
- CD8 Antigens/immunology
- Chromosomes, Human, Pair 6/genetics
- Epithelial Cells/immunology
- Genes, MHC Class I/genetics
- HLA Antigens/genetics
- Histocompatibility Antigens Class I/genetics
- Humans
- Immunity, Mucosal/genetics
- Killer Cells, Natural/immunology
- Major Histocompatibility Complex/genetics
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Receptors, Antigen, T-Cell/immunology
- Receptors, Immunologic/genetics
- Receptors, Immunologic/immunology
- Receptors, KIR
- T-Lymphocytes/immunology
- beta 2-Microglobulin/immunology
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Affiliation(s)
- R S Blumberg
- Gastroenterology Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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14
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Abstract
Iron is vital for almost all living organisms by participating in a wide variety of metabolic processes, including oxygen transport, DNA synthesis, and electron transport. However, iron concentrations in body tissues must be tightly regulated because excessive iron leads to tissue damage, as a result of formation of free radicals. Disorders of iron metabolism are among the most common diseases of humans and encompass a broad spectrum of diseases with diverse clinical manifestations, ranging from anemia to iron overload and, possibly, to neurodegenerative diseases. The molecular understanding of iron regulation in the body is critical in identifying the underlying causes for each disease and in providing proper diagnosis and treatments. Recent advances in genetics, molecular biology and biochemistry of iron metabolism have assisted in elucidating the molecular mechanisms of iron homeostasis. The coordinate control of iron uptake and storage is tightly regulated by the feedback system of iron responsive element-containing gene products and iron regulatory proteins that modulate the expression levels of the genes involved in iron metabolism. Recent identification and characterization of the hemochromatosis protein HFE, the iron importer Nramp2, the iron exporter ferroportin1, and the second transferrin-binding and -transport protein transferrin receptor 2, have demonstrated their important roles in maintaining body's iron homeostasis. Functional studies of these gene products have expanded our knowledge at the molecular level about the pathways of iron metabolism and have provided valuable insight into the defects of iron metabolism disorders. In addition, a variety of animal models have implemented the identification of many genetic defects that lead to abnormal iron homeostasis and have provided crucial clinical information about the pathophysiology of iron disorders. In this review, we discuss the latest progress in studies of iron metabolism and our current understanding of the molecular mechanisms of iron absorption, transport, utilization, and storage. Finally, we will discuss the clinical presentations of iron metabolism disorders, including secondary iron disorders that are either associated with or the result of abnormal iron accumulation.
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Affiliation(s)
- P T Lieu
- The R.W. Johnson Pharmaceutical Research Institute, 3210 Merryfield Row, San Diego, CA 92121, USA
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15
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Abstract
Remarkable progress is being made in understanding the molecular basis of disorders of human iron metabolism. Recent work has uncovered unanticipated relationships with the immune and nervous systems, intricate interconnections with copper metabolism, and striking homologies between yeast and human genes involved in the transport of transition metals. This review examines the clinical consequences of new insights into the pathophysiology of genetic abnormalities affecting iron metabolism. The proteins recently found to be involved in the absorption, transport, utilization, and storage of iron are briefly described, and the clinical manifestations of genetic disorders that affect these proteins are discussed. This chapter considers the most common inherited disorder in individuals of European ancestry (hereditary hemochromatosis), a widespread disease in sub-Saharan populations for which the genetic basis is still uncertain (African dietary iron overload), and several less frequent or rare disorders (juvenile hemochromatosis, atransferrinemia, aceruloplasminemia, hyperferritinemia with autosomal dominant congenital cataract, Friedreich's ataxia, and X-linked sideroblastic anemia with ataxia).
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Affiliation(s)
- S Sheth
- Department of Pediatrics, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
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16
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Levy JE, Montross LK, Andrews NC. Genes that modify the hemochromatosis phenotype in mice. J Clin Invest 2000; 105:1209-16. [PMID: 10791995 PMCID: PMC315447 DOI: 10.1172/jci9635] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hereditary hemochromatosis (HH) is a prevalent human disease caused by a mutation in HFE, which encodes an atypical HLA class I protein involved in regulation of intestinal iron absorption. To gain insight into the pathogenesis of hemochromatosis, we have bred Hfe knockout mice to strains carrying other mutations that impair normal iron metabolism. Compound mutant mice lacking both Hfe and its interacting protein, beta-2 microglobulin (B2m), deposit more tissue iron than mice lacking Hfe only, suggesting that another B2m-interacting protein may be involved in iron regulation. Hfe knockout mice carrying mutations in the iron transporter DMT1 fail to load iron, indicating that hemochromatosis involves iron flux through DMT1. Similarly, compound mutants deficient in both Hfe and hephaestin (Heph) show less iron loading than do Hfe knockout mice, indicating that iron absorption in hemochromatosis involves the function of Heph as well. Finally, compound mutants lacking Hfe and the transferrin receptor accumulate more tissue iron than do mice lacking Hfe alone, consistent with the idea that interaction between these two proteins contributes to the control of normal iron absorption. In addition to providing insight into the pathogenesis of HH, our results suggest that each of these genes might be a candidate modifier of the human hemochromatosis phenotype.
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Affiliation(s)
- J E Levy
- Division of Hematology-Oncology, Children's Hospital, Boston, Massachusetts 02115, USA
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Abstract
Iron deficiency during pregnancy affects a significant portion of women in countries with low economic wealth and is not uncommon in pregnant women in industrialized countries. Inadequate intake of iron related to diets poor in bioavailable iron is often responsible for iron deficiency before pregnancy, and metabolic adjustments (such as mobilization of iron stores and increased absorption) are insufficient to meet increasing needs during pregnancy. The effects of iron deficiency on the fetus are still controversial. Numerous measures, including the evaluation of erythrocyte ferritin, favor the hypothesis that the level of iron stores in newborns is related to maternal iron status and that the materno-fetal unit is dependent on exogenous iron, which is necessary to prevent iron deficiency in both mothers and infants. In industrialized countries, iron supplements should be prescribed for pregnant women in the third trimester, when the need for iron is prominent. In developing countries, supplementation should be initiated as soon as possible after conception because of the high prevalence of iron deficiency at the onset of pregnancy. The results of studies comparing intermittent with daily supplementation remain controversial.
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Affiliation(s)
- I Blot
- Laboratoire d'Hématologie Biologique, CHU Bicêtre 78, Le Kremlin-Bicêtre, France
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