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Kindi H, Willems C, Zhao M, Menzel M, Schmelzer CEH, Herzberg M, Fuhrmann B, Gallego-Ferrer G, Groth T. Metal Ion Doping of Alginate-Based Surface Coatings Induces Adipogenesis of Stem Cells. ACS Biomater Sci Eng 2022; 8:4327-4340. [PMID: 36174215 DOI: 10.1021/acsbiomaterials.2c00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metal ions are important effectors of protein and cell functions. Here, polyelectrolyte multilayers (PEMs) made of chitosan (Chi) and alginate (Alg) were doped with different metal ions (Ca2+, Co2+, Cu2+, and Fe3+), which can form bonds with their functional groups. Ca2+ and Fe3+ ions can be deposited in PEM at higher quantities resulting in more positive ζ potentials and also higher water contact angles in the case of Fe3+. An interesting finding was that the exposure of PEM to metal ions decreases the elastic modulus of PEM. Fourier transformed infrared (FTIR) spectroscopy of multilayers provides evidence of interaction of metal ions with the carboxylic groups of Alg but not for hydroxyl and amino groups. The observed changes in wetting and surface potential are partly related to the increased adhesion and proliferation of multipotent C3H10T1/2 fibroblasts in contrast to plain nonadhesive [Chi/Alg] multilayers. Specifically, PEMs doped with Cu2+ and Fe3+ ions greatly promote cell attachment and adipogenic differentiation, which indicates that changes in not only surface properties but also the bioactivity of metal ions play an important role. In conclusion, metal ion-doped multilayer coatings made of alginate and chitosan can promote the differentiation of multipotent cells on implants without the use of other morphogens like growth factors.
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Affiliation(s)
- Husnia Kindi
- Institute of Pharmacy, Department Biomedical Materials, Martin Luther University Halle-Wittenberg, Heinrich-Damerow Strasse 4, 06120 Halle (Saale), Germany
| | - Christian Willems
- Institute of Pharmacy, Department Biomedical Materials, Martin Luther University Halle-Wittenberg, Heinrich-Damerow Strasse 4, 06120 Halle (Saale), Germany
| | - Mingyan Zhao
- Stem Cell Research and Cellular Therapy Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524003, China
| | - Matthias Menzel
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Walter-Hülse-Strasse 1, 06120 Halle (Saale), Germany
| | - Christian E H Schmelzer
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Walter-Hülse-Strasse 1, 06120 Halle (Saale), Germany
| | - Martin Herzberg
- Molecular Microbiology, Institute for Biology/Microbiology, Martin-Luther-University, Halle- Wittenberg, Kurt-Mothes-Strasse 3, 06120 Halle (Saale), Germany
| | - Bodo Fuhrmann
- Institute of Physics, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, 06120 Halle (Saale), Germany.,Interdisciplinary Center of Materials Science, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, 06120 Halle (Saale), Germany
| | - Gloria Gallego-Ferrer
- Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.,Biomedical Research Networking Centre in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 46022 Valencia, Spain
| | - Thomas Groth
- Institute of Pharmacy, Department Biomedical Materials, Martin Luther University Halle-Wittenberg, Heinrich-Damerow Strasse 4, 06120 Halle (Saale), Germany.,Interdisciplinary Center of Materials Science, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, 06120 Halle (Saale), Germany
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Kindi H, Menzel M, Heilmann A, Schmelzer CEH, Herzberg M, Fuhrmann B, Gallego-Ferrer G, Groth T. Effect of metal ions on the physical properties of multilayers from hyaluronan and chitosan, and the adhesion, growth and adipogenic differentiation of multipotent mouse fibroblasts. SOFT MATTER 2021; 17:8394-8410. [PMID: 34550141 DOI: 10.1039/d1sm00405k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Polyelectrolyte multilayers (PEMs) consisting of the polysaccharides hyaluronic acid (HA) as the polyanion and chitosan (Chi) as the polycation were prepared with layer-by-layer technique (LbL). The [Chi/HA]5 multilayers were exposed to solutions of metal ions (Ca2+, Co2+, Cu2+ and Fe3+). Binding of metal ions to [Chi/HA]5 multilayers by the formation of complexes with functional groups of polysaccharides modulates their physical properties and the bioactivity of PEMs with regard to the adhesion and function of multipotent murine C3H10T1/2 embryonic fibroblasts. Characterization of multilayer formation and surface properties using different analytical methods demonstrates changes in the wetting, surface potential and mechanical properties of multilayers depending on the concentration and type of metal ion. Most interestingly, it is observed that Fe3+ metal ions greatly promote adhesion and spreading of C3H10T1/2 cells on the low adhesive [Chi/HA]5 PEM system. The application of intermediate concentrations of Cu2+, Ca2+ and Co2+ as well as low concentrations of Fe3+ to PEMs also results in increased cell spreading. Moreover, it can be shown that complex formation of PEMs with Cu2+ and Fe3+ ions leads to increased metabolic activity in cells after 24 h and induces cell differentiation towards adipocytes in the absence of any additional adipogenic media supplements. Overall, complex formation of [Chi/HA]5 PEM with metal ions like Cu2+ and Fe3+ represents an interesting and cheap alternative to the use of growth factors for making cell-adhesive coatings and guiding stem cell differentiation on implants and scaffolds to regenerate connective-type of tissues.
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Affiliation(s)
- Husnia Kindi
- Department Biomedical Materials, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany.
| | - Matthias Menzel
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, 06120 Halle (Saale), Germany
| | - Andreas Heilmann
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, 06120 Halle (Saale), Germany
| | - Christian E H Schmelzer
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, 06120 Halle (Saale), Germany
| | - Martin Herzberg
- Molecular Microbiology, Institute for Biology/Microbiology, Martin-Luther-University, Halle-Wittenberg, Germany
| | - Bodo Fuhrmann
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale), Germany
- Interdisciplinary Center of Materials Science, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Gloria Gallego-Ferrer
- Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Caminode Veras/n, 46022 Valencia, Spain
- Biomedical Research Networking Centre in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 46022 Valencia, Spain
| | - Thomas Groth
- Department Biomedical Materials, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany.
- Interdisciplinary Center of Materials Science, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Laboratory of Biomedical Nanotechnologies, Institute of Bionic Technologies and Engineering, I.M. Sechenov First Moscow State University, 119991, Trubetskaya street 8, Moscow, Russian Federation
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Dar MA, Ahmed R, Urwat U, Ahmad SM, Dar PA, Kushoo ZA, Dar TA, Mumtaz PT, Bhat SA, Amin U, Shabir N, Bhat HF, Shah RA, Ganai NA, Heidari M. Expression kinetics of natural resistance associated macrophage protein (NRAMP) genes in Salmonella Typhimurium-infected chicken. BMC Vet Res 2018; 14:180. [PMID: 29884179 PMCID: PMC5994117 DOI: 10.1186/s12917-018-1510-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 05/31/2018] [Indexed: 11/24/2022] Open
Abstract
Background Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) is a zoonotic pathogen responsible for severe intestinal pathology in young chickens. Natural resistance-associated macrophage protein (NRAMP) family has been shown to be associated with resistance to intracellular pathogens, including Salmonella Typhimurium. The role of NRAMP proteins in macrophage defence against microbial infection has been ascribed to changes in the metal-ion concentrations inside the bacteria-containing phagosomes. The present study was conducted to investigate tissue-specific (liver, spleen and caecum) expression kinetics of NRAMP gene family (NRAMP1 and NRAMP2) in broilers from day 0 to day 15 after Salmonella Typhimurium challenge concomitant to clinical, blood biochemical and immunological parameters survey. Results Clinical symptoms appeared 4 days post-infection (dpi) in infected birds. Symptoms like progressive weakness, anorexia, diarrhoea and lowering of the head were seen in infected birds one-week post-infection. On postmortem examination, liver showed congestion, haemorrhage and necrotic foci on the surface, while as the spleen, lungs and intestines revealed congestion and haemorrhages. Histopathological alterations were principally found in liver comprising of necrosis, reticular endothelial hyperplasia along with mononuclear cell and heterophilic infiltration. Red Blood Cell (RBC) count, Haemoglobin (Hb) and Packed Cell Volume (PCV) decreased significantly (P < 0.05) in blood while heterophil counts increased up to 7 days post-infection. Serum glucose, aspartate transaminase (AST) and alanine transaminase (ALT) enzymes concentrations increased significantly throughout the study. A gradual increase of specific humoral IgG response confirmed Salmonella infection. Meanwhile, expression of NRAMP1 and NRAMP2 genes was differentially regulated after infection in tissues such as liver, spleen and caecum known to be the target of Salmonella Typhimurium replication in the chicken. Conclusion Thus the specific roles of NRAMP1 and NRAMP2 genes in Salmonella Typhimurium induced disease may be supposed from their differential expression according to tissues and timing after per os infection. However, these roles remain to be analyzed related to the severity of the disease which can be estimated by blood biochemistry and immunological parameters.
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Affiliation(s)
- Mashooq Ahmad Dar
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India.,Depatment of Biochemistry, University of Kashmir, Srinagar, India
| | - Raashid Ahmed
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Uneeb Urwat
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Syed Mudasir Ahmad
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India.
| | - Pervaiz Ahmad Dar
- Division of Veterinary Microbiology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, SKUAST-K, Srinagar, India
| | - Zahid Amin Kushoo
- Division of Veterinary Microbiology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, SKUAST-K, Srinagar, India
| | - Tanveer Ali Dar
- Depatment of Biochemistry, University of Kashmir, Srinagar, India
| | - Peerzada Tajamul Mumtaz
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Shakil Ahmad Bhat
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Umar Amin
- Division of Veterinary Pathology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, SKUAST-K, Srinagar, India
| | - Nadeem Shabir
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Hina Fayaz Bhat
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Riaz Ahmad Shah
- Division of Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, Sher-e- Kashmir University of Agricultural Sciences and Technology - Kashmir, Srinagar, India
| | - Nazir Ahmad Ganai
- Division of Animal Breeding and Genetics, Faculty of Veterinary Sciences and Animal Husbandry, Shuhama, SKUAST-K, Srinagar, India
| | - Mohammad Heidari
- USDA, Agricultural Research Service, Avian Disease and Oncology Laboratory, 4279 E. Mount Hope Rd., East Lansing, MI, 48823, USA
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G9a regulates breast cancer growth by modulating iron homeostasis through the repression of ferroxidase hephaestin. Nat Commun 2017; 8:274. [PMID: 28819251 PMCID: PMC5561105 DOI: 10.1038/s41467-017-00350-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 06/23/2017] [Indexed: 01/16/2023] Open
Abstract
G9a, a H3K9 methyltransferase, shows elevated expression in many types of human cancers, particularly breast cancer. However, the tumorigenic mechanism of G9a is still far from clear. Here we report that G9a exerts its oncogenic function in breast cancer by repressing hephaestin and destruction cellular iron homeostasis. In the case of pharmacological inhibition or short hairpin RNA interference-mediated suppression of G9a, the expression and activity of hephaestin increases, leading to the observed decrease of intracellular labile iron content and the disturbance of breast cancer cell growth in vitro and in vivo. We also provide evidence that G9a interacts with HDAC1 and YY1 to form a multi-molecular complex that contributes to hephaestin silencing. Furthermore, high G9a expression and low hephaestin expression correlate with poor survival of breast cancer are investigated. All these suggest a G9a-dependent epigenetic program in the control of iron homeostasis and tumor growth in breast cancer. G9a is a histone methyltransferase highly expressed in several cancers including breast cancer. Here the authors propose a mechanism through which G9a promotes breast cancer by regulating iron metabolism through the repression of ferroxidase hephaestin.
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5
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McCarthy RC, Park YH, Kosman DJ. sAPP modulates iron efflux from brain microvascular endothelial cells by stabilizing the ferrous iron exporter ferroportin. EMBO Rep 2014; 15:809-15. [PMID: 24867889 DOI: 10.15252/embr.201338064] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A sequence within the E2 domain of soluble amyloid precursor protein (sAPP) stimulates iron efflux. This activity has been attributed to a ferroxidase activity suggested for this motif. We demonstrate that the stimulation of efflux supported by this peptide and by sAPPα is due to their stabilization of the ferrous iron exporter, ferroportin (Fpn), in the plasma membrane of human brain microvascular endothelial cells (hBMVEC). The peptide does not bind ferric iron explaining why it does not and thermodynamically cannot promote ferrous iron autoxidation. This peptide specifically pulls Fpn down from the plasma membrane of hBMVEC; based on these results, FTP, for ferroportin-targeting peptide, correctly identifies the function of this peptide. The data suggest that in stabilizing Fpn via the targeting due to the FTP sequence, sAPP will increase the flux of iron into the cerebral interstitium. This inference correlates with the observation of significant iron deposition in the amyloid plaques characteristic of Alzheimer's disease.
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Affiliation(s)
- Ryan C McCarthy
- Department of Biochemistry, School of Medicine and Biomedical Sciences University at Buffalo, Buffalo, NY, USA
| | - Yun-Hee Park
- Department of Biochemistry, School of Medicine and Biomedical Sciences University at Buffalo, Buffalo, NY, USA
| | - Daniel J Kosman
- Department of Biochemistry, School of Medicine and Biomedical Sciences University at Buffalo, Buffalo, NY, USA
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Vivot RM, Goitia B, Usach V, Setton-Avruj PC. DMT1 as a candidate for non-transferrin-bound iron uptake in the peripheral nervous system. Biofactors 2013; 39:476-84. [PMID: 23361852 DOI: 10.1002/biof.1088] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/21/2012] [Indexed: 12/22/2022]
Abstract
Iron, either in its chelated form or as holotransferrin (hTf), prevents the dedifferentiation of Schwann cells (SC), cells responsible for the myelination of the peripheral nervous system (PNS). This dedifferentiation is promoted by serum deprivation through cAMP release, PKA activation, and CREB phosphorylation. Since iron elicits its effect in a transferrin (Tf)-free environment, in this work we postulate that non-transferrin-bound iron (NTBI) uptake must be involved. Divalent metal transporter 1(DMT1) has been widely described in literature as a key player in iron metabolism, but never before in the PNS context. The presence of DMT1 was demonstrated in nerve homogenate, isolated adult-rat myelin, and cultured SC by Western Blot (WB) analysis and confirmed through its colocalization with S-100β (SC marker) by immunocytochemical and immunohistochemical analyses. Furthermore, the existence of its mRNA was verified in sciatic nerve homogenate by RT-PCR and throughout SC maturational stages. Finally, we describe DMT1's subcellular location in the plasma membrane by confocal microscopy of SC and WB of different subcellular fractions. These data allow us to suggest the participation of DMT1 as part of a Tf independent iron uptake mechanism in SC and lead us to postulate a crucial role for iron in SC maturation and, as a consequence, in PNS myelination.
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Affiliation(s)
- Rocio Martínez Vivot
- Instituto de Química y Fisicoquímica Biológica (IQUIFIB), UBA-CONICET, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 956- Buenos Aires C1113AAD, Argentina
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7
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Wolber FM, Beck KL, Conlon CA, Kruger MC. Kiwifruit and Mineral Nutrition. NUTRITIONAL BENEFITS OF KIWIFRUIT 2013; 68:233-56. [DOI: 10.1016/b978-0-12-394294-4.00013-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
Iron metabolism has been intensively examined over the last decade and there are many new players in this field which are worth to be introduced. Since its discovery many studies confirmed role of liver hormone hepcidin as key regulator of iron metabolism and pointed out liver as the central organ of system iron homeostasis. Liver cells receive multiple signals related to iron balance and respond by transcriptional regulation of hepcidin expression. This liver hormone is negative regulator of iron metabolism that represses iron efflux from macrophages, hepatocytes and enterocytes by its binding to iron export protein ferroportin. Ferroportin degradation leads to cellular iron retention and decreased iron availability. At level of a cell IRE/IRP (iron responsive elements/iron responsive proteins) system allows tight regulation of iron assimilation that prevents an excess of free intracellular iron which could lead to oxidative stress and damage of DNA, proteins and lipid membranes by ROS (reactive oxygen species). At the same time IRE/IRP system provides sufficient iron in order to meet the metabolic needs. Recently a significant progress in understanding of iron metabolism has been made and new molecular participants have been characterized. Article gives an overview of the current understanding of iron metabolism: absorption, distribution, cellular uptake, release, and storage. We also discuss mechanisms underlying systemic and cellular iron regulation with emphasis on central regulatory hormone hepcidin.
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Affiliation(s)
- Leida Tandara
- Department of Medical Laboratory Diagnosis, University Hospital Center Split, Split, Croatia.
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9
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Huang K, Li H, Shen H, Li M. Psychological stress expands low molecular weight iron pool in cerebral cortex, hippocampus, and striatum of rats. Biol Trace Elem Res 2012; 146:79-85. [PMID: 21993966 DOI: 10.1007/s12011-011-9230-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 10/04/2011] [Indexed: 01/30/2023]
Abstract
We have previously demonstrated that psychological stress (PS) can cause iron to accumulate in the cerebral cortex, hippocampus, and striatum of rats. However, why iron accumulates and in what oxidation state iron it accumulates in the brain of PS-exposed rats has not been well elucidated. In the present study, we investigated the influence of PS on the low molecular weight iron pool (LMWIP) in the rat brain. The results showed that: (1) PS significantly expanded LMWIP in the cerebral cortex, hippocampus, and striatum in rats; (2) PS caused derangement of pyramidal cells and reduced the layers of pyramidal CA1 and CA2 neurons; (3) PS exposure greatly lowered the expression of ferritin (Fn) and hephaestin (HP) in the rat cortex and hippocampus; and (4) PS decreased superoxide dismutase, glutathione peroxidase, and glutathione level and increased malondialdehyde level in the cerebral cortex, hippocampus, and striatum in rats. These results indicated that PS could expand LMWIP significantly, which may be attributed to PS-induced decrease in Fn, HP expression, and the subsequent reduction in iron storage and utilization, and expansion of LMWIP could in turn lead to aggravation of oxidative damage.
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Affiliation(s)
- Kai Huang
- Department of Military Hygiene, Second Military Medical University, No. 800 Xiangyin Road, Yangpu District, Shanghai, 200433, China
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10
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Alissa EM, Ferns GA. Heavy metal poisoning and cardiovascular disease. J Toxicol 2011; 2011:870125. [PMID: 21912545 PMCID: PMC3168898 DOI: 10.1155/2011/870125] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 06/28/2011] [Indexed: 02/07/2023] Open
Abstract
Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed.
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Affiliation(s)
- Eman M. Alissa
- Faculty of Medicine, King Abdul Aziz University, P.O. Box 12713, Jeddah 21483, Saudi Arabia
| | - Gordon A. Ferns
- Institute for Science & Technology in Medicine, Faculty of Health, University of Keele, Staffordshire ST4 7QB, UK
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11
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Abstract
α-synuclein (αS) is a cellular protein mostly known for the association of its aggregated forms with a variety of diseases that include Parkinson's disease and Dementia with Lewy Bodies. While the role of αS in disease is well documented there is currently no agreement on the physiological function of the normal isoform of the protein. Here we provide strong evidence that αS is a cellular ferrireductase, responsible for reducing iron (III) to bio available iron (II). The recombinant form of the protein has a V(Max) of 2.72 nmols/min/mg and K(m) 23 µM. This activity is also evident in lysates from neuronal cell lines overexpressing αS. This activity is dependent on copper bound to αS as a cofactor and NADH as an electron donor. Overexpression of α-synuclein by cells significantly increases the percentage of iron (II) in cells. The common disease mutations associated with increased susceptibility to PD show no [corrected] differences in activity or iron (II) levels. This discovery may well provide new therapeutic targets for PD and Lewy body dementias.
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12
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Messner B, Bernhard D. Cadmium and cardiovascular diseases: cell biology, pathophysiology, and epidemiological relevance. Biometals 2010; 23:811-22. [PMID: 20213268 DOI: 10.1007/s10534-010-9314-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 02/17/2010] [Indexed: 10/19/2022]
Abstract
Today cardiovascular diseases (CVDs) are the killer number one world wide. In 2004 an estimated 17.1 million people died due to CVDs and this number will further increase to an estimated 23.6 million by 2030. Importantly, currently known risk factors, like hypertension, and hypercholesterolemia, can only be made responsible for about 50-75% of all CVDs, highlighting the urgent need to search for and define new CVD risk factors. Cadmium (Cd) was shown to have the potential to serve as one such novel risk factor, as it was demonstrated-in vitro, in animal studies, and in human studies-that Cd causes atherosclerosis (the basis of most CVDs). Herein, we discuss the molecular and cellular biological effects of Cd in the cardiovascular system; we present concepts on the pathophysiology of Cd-caused atherosclerosis, and provide data that indicate an epidemiological relevance of Cd as a risk factor for CVDs.
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Affiliation(s)
- Barbara Messner
- Cardiothoracic Surgery, Research Laboratories, Department of Surgery, Medical University of Vienna, Währinger Gürtel 18-20, Vienna, Austria
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13
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Hudson DM, Curtis SB, Smith VC, Griffiths TAM, Wong AYK, Scudamore CH, Buchan AMJ, MacGillivray RTA. Human hephaestin expression is not limited to enterocytes of the gastrointestinal tract but is also found in the antrum, the enteric nervous system, and pancreatic {beta}-cells. Am J Physiol Gastrointest Liver Physiol 2010; 298:G425-32. [PMID: 20019163 DOI: 10.1152/ajpgi.00453.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hephaestin (Hp) is a membrane protein with ferroxidase activity that converts Fe(II) to Fe(III) during the absorption of nutritional iron in the gut. Using anti-peptide antibodies to predicted immunogenic regions of rodent Hp, previous immunocytochemical studies in rat, mouse, and human gut tissues localized Hp to the basolateral membranes of the duodenal enterocytes where the Hp was predicted to aid in the transfer of Fe(III) to transferrin in the blood. We used a recombinant soluble form of human Hp to obtain a high-titer polyclonal antibody to Hp. This antibody was used to identify the intracellular location of Hp in human gut tissue. Our immunocytochemical studies confirmed the previous localization of Hp in human enterocytes. However, we also localized Hp to the entire length of the gastrointestinal tract, the antral portion of the stomach, and to the enteric nervous system (both the myenteric and submucous plexi). Hp was also localized to human pancreatic beta-cells. In addition to its expression in the same cells as Hp, ferroportin was also localized to the ductal cells of the exocrine pancreas. The localization of the ferroxidase Hp to the neuronal plexi and the pancreatic beta cells suggests a role for the enzymatic function of Hp in the protection of these specialized cell types from oxidative damage.
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Affiliation(s)
- David M Hudson
- Centre for Blood Research and Department of Biochemistry, University of British Columbia, Vancouver, Canada
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14
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Pitarresi G, Tripodo G, Cavallaro G, Palumbo FS, Giammona G. Inulin–iron complexes: A potential treatment of iron deficiency anaemia. Eur J Pharm Biopharm 2008; 68:267-76. [PMID: 17574404 DOI: 10.1016/j.ejpb.2007.05.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 05/04/2007] [Accepted: 05/07/2007] [Indexed: 10/23/2022]
Abstract
The aim of this work was that to synthesize macromolecular derivatives based on inulin able to complex iron and useful in the treatment of iron deficiency anaemia. Carboxylated or thiolated/carboxylated inulin derivatives were obtained by single or double step reactions, respectively. The first one was obtained by reaction of inulin (INU) with succinic anhydride (SA) alone obtaining INU-SA derivative; the second one was obtained by the reaction of INU with succinic anhydride and subsequent reaction of INU-SA with cysteine; both derivatives were treated with ferric chloride in order to obtain the INU-SA-Fe(III) and INU-SA-Cys-Fe(III) complexes. Both complexes showed an excellent biodegradability in the presence of inulinase and pronounced mucoadhesion properties; in particular, thiolated derivative INU-SA-Cys showed greater mucoadhesive properties than polyacrylic acid chosen, as a positive reference polymer, and a good iron release profile in condition mimicking the intestinal tract. These results suggest the potential employment of such systems in the oral treatment of iron deficiency anaemia or as supplement of iron in foods.
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Affiliation(s)
- Giovanna Pitarresi
- Dipartimento di Chimica e Tecnologie Farmaceutiche, Università degli Studi di Palermo, Palermo, Italy.
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15
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Hudson DM, Krisinger MJ, Griffiths TA, MacGillivray RT. Neither human hephaestin nor ceruloplasmin forms a stable complex with transferrin. J Cell Biochem 2008; 103:1849-55. [DOI: 10.1002/jcb.21566] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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16
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Lao BJ, Kamei DT. A compartmental model of iron regulation in the mouse. J Theor Biol 2006; 243:542-54. [PMID: 16935308 DOI: 10.1016/j.jtbi.2006.06.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 06/06/2006] [Accepted: 06/16/2006] [Indexed: 11/27/2022]
Abstract
A simple compartmental model is developed for investigating the mechanism of iron homeostasis. In contrast to previous mathematical models of iron metabolism, the liver is included as a key site of iron regulation. Compartments for free iron in blood, diferric transferrin (Tf) in blood, hepatocytes, red blood cells, and macrophages are included, and their roles in iron regulation are explored. The function of hepcidin in regulating iron absorption is modeled through an inverse relationship between hepatocyte transferrin receptor 2 (TfR2) levels and the rate of iron export processes mediated by ferroportin (Fpn). Simulations of anemia and erythropoiesis stimulation support the idea that the iron demands of the erythroid compartment can be communicated through diferric Tf. The iron-responsive element of Fpn is found to be important for stabilizing intracellular iron stores in response to changing iron demands and allowing proper iron regulation through diferric Tf. The contribution of iron dysregulation to the pathogenesis of iron overload disorders is also investigated. It is shown that the characteristics of HFE hemochromatosis can be reproduced by increasing the setpoint of iron absorption in the duodenum to a level where the system cannot downregulate iron absorption to meet the iron excretion rate.
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Affiliation(s)
- Bert J Lao
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
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17
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Abstract
Hepcidin evolves as a potent hepatocyte-derived regulator of the body's iron distribution piloting the flow of iron via, and directly binding, to the cellular iron exporter ferroportin. The hepcidin-ferroportin axis dominates the iron egress from all cellular compartments that are critical to iron homeostasis, namely placental syncytiotrophoblasts, duodenal enterocytes, hepatocytes and macrophages of the reticuloendothelial system. The gene that encodes hepcidin expression (HAMP) is subject to regulation by proinflammatory cytokines, such as IL-6 and IL-1; excessive hepcidin production explains the relative deficiency of iron during inflammatory states, eventually resulting in the anaemia of inflammation. The haemochromatosis genes HFE, TfR2 and HJV potentially facilitate the transcription of HAMP. Disruption of each of the four genes leads to a diminished hepatic release of hepcidin consistent with both a dominant role of hepcidin in hereditary haemochromatosis and an upstream regulatory role of HFE, TfR2 and HJV on HAMP expression. The engineered generation of hepcidin agonists, mimetics or antagonists could largely broaden current therapeutic strategies to redirect the flow of iron.
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Affiliation(s)
- R Deicher
- Department of Medicine III, Medical University of Vienna, Vienna, Austria
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18
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Moriya M, Linder MC. Vesicular transport and apotransferrin in intestinal iron absorption, as shown in the Caco-2 cell model. Am J Physiol Gastrointest Liver Physiol 2006; 290:G301-9. [PMID: 16179601 DOI: 10.1152/ajpgi.00029.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The potential roles of vesicular transport and apotransferrin (entering from the blood) in intestinal Fe absorption were investigated using Caco-2 cell monolayers with tight junctions in bicameral chambers as a model. As shown previously, addition of 39 microM apotransferrin (apoTf) to the basolateral fluid during absorption studies markedly stimulated overall transport of 1 microM (59)Fe from the apical to the basal chamber and stimulated its basolateral release from prelabeled cells, implicating endo- and exocytosis. Rates of transport more than doubled. Uptake was also stimulated, but only 20%. Specific inhibitors of aspects of vesicular trafficking were applied to determine their potential effects on uptake, retention, and basolateral (overall) transport of (59)Fe. Nocodazole and 5'-(4-fluorosulfonylbenzoyl)-adenosine each reduced uptake and basolateral transport up to 50%. Brefeldin A inhibited about 10%. Tyrphostin A8 (AG10) reduced uptake 35% but markedly stimulated basolateral efflux, particularly that dependent on apoTf. Cooling of cells to 4 degrees C (which causes depolymerization of microtubules and lowers energy availability) profoundly inhibited uptake and basolateral transfer of Fe (7- to 12-fold). Apical efflux (which was substantial) was not temperature affected. Our results support the involvement of apoTf cycling in intestinal Fe absorption and indicate that as much as half of the iron uses apoTf and non-apoTf-dependent vesicular pathways to cross the basolateral membrane and brush border of enterocytes.
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Affiliation(s)
- Mizue Moriya
- Department of Chemistry and Biochemistry, California State University, Fullerton, CA 91834-6866, USA
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19
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Abstract
Transfer of iron from the mucosa is a critical step in dietary iron assimilation that is tightly regulated to ensure the appropriate amount of iron is absorbed to meet the body's demands. Too much iron is highly toxic, and failure to properly control intestinal iron export causes iron overload associated with hereditary forms of hemochromatosis. One form of genetic iron overload, ferroportin disease, originates due to defects in ferroportin, the membrane iron exporter. Ferroportin acts in conjunction with the intestinal ferroxidase hephaestin to mediate release of iron from the enterocyte. How iron is then acquired by transferrin and released into circulation remains an unknown step in this process.
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Affiliation(s)
- Marianne Wessling-Resnick
- Dept. of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA.
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20
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Petrak J, Vyoral D. Hephaestin—a ferroxidase of cellular iron export. Int J Biochem Cell Biol 2005; 37:1173-8. [PMID: 15778082 DOI: 10.1016/j.biocel.2004.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Indexed: 01/09/2023]
Abstract
Hephaestin is a transmembrane copper-dependent ferroxidase necessary for effective iron transport from intestinal enterocytes into the circulation. Hephaestin is mutated in sex-linked anemia (sla) mice. The initial uptake of iron from the diet in these animals is normal, but the basolateral export of iron from enterocytes is defective, resulting in iron deficiency and microcytic hypochromic anemia. In addition to the small intestine, hephaestin is expressed to a lesser extent in colon, spleen, placenta and kidney but its role in these tissues remains unknown. So far, hephaestin has not been linked to a human disease.
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Affiliation(s)
- Jiri Petrak
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Praha 2, Czech Republic.
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21
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Bridges CC, Zalups RK. Molecular and ionic mimicry and the transport of toxic metals. Toxicol Appl Pharmacol 2005; 204:274-308. [PMID: 15845419 PMCID: PMC2409291 DOI: 10.1016/j.taap.2004.09.007] [Citation(s) in RCA: 540] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Accepted: 09/08/2004] [Indexed: 01/11/2023]
Abstract
Despite many scientific advances, human exposure to, and intoxication by, toxic metal species continues to occur. Surprisingly, little is understood about the mechanisms by which certain metals and metal-containing species gain entry into target cells. Since there do not appear to be transporters designed specifically for the entry of most toxic metal species into mammalian cells, it has been postulated that some of these metals gain entry into target cells, through the mechanisms of ionic and/or molecular mimicry, at the site of transporters of essential elements and/or molecules. The primary purpose of this review is to discuss the transport of selective toxic metals in target organs and provide evidence supporting a role of ionic and/or molecular mimicry. In the context of this review, molecular mimicry refers to the ability of a metal ion to bond to an endogenous organic molecule to form an organic metal species that acts as a functional or structural mimic of essential molecules at the sites of transporters of those molecules. Ionic mimicry refers to the ability of a cationic form of a toxic metal to mimic an essential element or cationic species of an element at the site of a transporter of that element. Molecular and ionic mimics can also be sub-classified as structural or functional mimics. This review will present the established and putative roles of molecular and ionic mimicry in the transport of mercury, cadmium, lead, arsenic, selenium, and selected oxyanions in target organs and tissues.
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Affiliation(s)
- Christy C Bridges
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, GA 31207, USA.
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22
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Tsabar N, Gefen A, Elias S, Frank D. Aggregation of maternal pigment granules is induced by the cytosolic discoidin domain of theXenopus Del1 protein. Dev Dyn 2005; 233:224-32. [PMID: 15765521 DOI: 10.1002/dvdy.20308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Xenopus oocytes generate pigment granules (melanosomes) that predominantly localize to the animal hemisphere cortex. During embryonic development, these granules are located near the membranes of outer layer ectoderm cells. We report a novel phenotype found during an expression cloning screen in Xenopus laevis embryos. The phenotype is characterized by dissociation of pigment granules from the cell membrane to form large central aggregates. This phenomenon was induced by a truncated form of the Xenopus Del1 (XDel1) protein that contains only the C-terminal discoidin (D2) domain. This truncated form of XDel1 localized to membranes as shown by a chimeric enhanced green fluorescent protein construct. Although a similar localization occurred in immature oocytes, dissociation of pigment granules was limited to the oocyte vegetal hemisphere. The full-length XDel1 cDNA was cloned, and XDel1 mRNA expression was found to be ubiquitous and continuous from early oocyte to tail bud stages, with a transient enrichment in the cement gland. Ectopic expression of various deletion or full-length constructs or antisense morpholino oligonucleotides did not induce any significant developmental phenotypes.
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Affiliation(s)
- Nir Tsabar
- Department of Biochemistry, The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel
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23
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Kielmanowicz MG, Laham N, Coligan JE, Lemonnier F, Ehrlich R. Mouse HFE inhibits Tf-uptake and iron accumulation but induces non-transferrin bound iron (NTBI)-uptake in transformed mouse fibroblasts. J Cell Physiol 2004; 202:105-14. [PMID: 15389541 DOI: 10.1002/jcp.20095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Iron-uptake and storage are tightly regulated to guarantee sufficient iron for essential cellular processes and to prevent the production of damaging free radicals. A non-classical class I MHC molecule, the hemochromatosis factor (HFE), has been shown to regulate iron metabolism, potentially via its interaction with the transferrin receptor. Whereas, the effect of human HFE (hHFE) on transferrin/transferrin receptor association, as well as on transferrin receptor recycling and the level of cellular iron pools in various cell lines was analyzed, very little is known about the mouse HFE (mHFE) protein. In the following study, our aim was to analyze in more detail the function of mHFE. Surprisingly, we observed that over-expression of mHFE, but not of hHFE, in a mouse transformed cell line, results in a most significant inhibition of transferrin-uptake which correlated with apoptotic cell death. mHFE inhibited transferrin-uptake immediately following transfection and this inhibition persisted in the surviving stable transfectants. Concomitantly, cellular iron derived from transferrin-iron uptake was dramatically limited. The activation of a non-transferrin bound iron-uptake pathway that functions in the stable mHFE-transfected clones could explain their normal growth curves and survival. The hypothesis that iron starvation can induce iron-uptake by a novel transferrin-independent pathway is discussed.
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Affiliation(s)
- Merav Gleit Kielmanowicz
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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24
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Simovich M, Hainsworth LN, Fields PA, Umbreit JN, Conrad ME. Localization of the iron transport proteins Mobilferrin and DMT-1 in the duodenum: the surprising role of mucin. Am J Hematol 2003; 74:32-45. [PMID: 12949888 DOI: 10.1002/ajh.10383] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
There are two pathways for inorganic iron uptake in the intestine, the ferric pathway, mediated by the key protein mobilferrin, and the ferrous pathway, mediated by DMT-1. Previous studies reported that the amount of DMT-1 increased in the intestinal mucosa in iron deficiency and the increase was seen in the apical portion of the villus of the duodenal mucosa. Mobilferrin did not quantitatively increase but became localized at the cell membrane. However, studies on fresh tissue have not previously been performed and the localization to the microvillae has not been demonstrated. In order to more definitively localize these proteins immunofluorescent and electron microscopic studies were undertaken. Samples were also subjected to biochemical analysis and Western analysis. In iron-deficient animals both DMT-1 and Mobilferrin were concentrated in the apical surface of the villae. Electron microscopy revealed that the majority of this increase in the amount of these proteins near the luminal surface was due to increased binding of the proteins to mucin in vesicles near the surface. A significant portion of the iron transport proteins was localized in the goblet cells and outside the cell in the luminal mucin, as demonstrated by immunofluorescence, electron microscopy, and isolation of the mucin by cesium chloride gradient centrifugation and Western analysis. A new model for the transport of metal ions was suggested. The metal transport proteins travel from vesicles inside the cell out to the lumen mucin. This increases the surface area and allows a greater portion of the lumen contents to be exposed to the binding proteins. Once the metal is bound to the externalized protein it is internalized into the cell. This explains many of the unique properties of the iron-binding proteins and suggests that it may be a more general model for the absorption of other nutrients.
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25
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Abstract
Brilliant new discoveries in the field of iron metabolism have revealed novel transmembrane iron transporters, novel hormones that regulate iron traffic, and iron's control of gene expression. An important role for iron in the embryonic kidney was first identified by Ekblom, who studied transferrin (Landschulz W and Ekblom P. J Biol Chem 260: 15580-15584, 1985; Landschulz W, Thesleff I, and Ekblom P. J Cell Biol 98: 596-601, 1984; Thesleff I, Partanen AM, Landschulz W, Trowbridge IS, and Ekblom P. Differentiation 30: 152- 158, 1985). Nevertheless, how iron traffics to developing organs remains obscure. This review discusses a member of the lipocalin superfamily, 24p3 or neutrophil gelatinase-associated lipocalcin (NGAL), which induces the formation of kidney epithelia. We review the data showing that lipocalins transport low-molecular-weight chemical signals and data indicating that 24p3/NGAL transports iron. We compare 24p3/NGAL to transferrin and a variety of other iron trafficking pathways and suggest specific roles for each in iron transport.
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Affiliation(s)
- Jun Yang
- Dept. of Medicine and Anatomy and Cell Biology, College of Physicians and Surgeons of Columbia Univ., 630 W 168th St., New York, NY 10032, USA
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26
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Chung J, Wessling-Resnick M. Molecular mechanisms and regulation of iron transport. Crit Rev Clin Lab Sci 2003; 40:151-82. [PMID: 12755454 DOI: 10.1080/713609332] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Iron homeostasis is primarily maintained through regulation of its transport. This review summarizes recent discoveries in the field of iron transport that have shed light on the molecular mechanisms of dietary iron uptake, pathways for iron efflux to and between peripheral tissues, proteins implicated in organellar transport of iron (particularly the mitochondrion), and novel regulators that have been proposed to control iron assimilation. The transport of both transferrin-bound and nontransferrin-bound iron to peripheral tissues is discussed. Finally, the regulation of iron transport is also considered at the molecular level, with posttranscriptional, transcriptional, and posttranslational control mechanisms being reviewed.
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Affiliation(s)
- Jayong Chung
- Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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27
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Strube YNJ, Beard JL, Ross AC. Iron deficiency and marginal vitamin A deficiency affect growth, hematological indices and the regulation of iron metabolism genes in rats. J Nutr 2002; 132:3607-15. [PMID: 12468596 DOI: 10.1093/jn/132.12.3607] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Iron deficiency and marginal vitamin A (VA) deficiency frequently coexist and affect billions of people, mostly children and women, worldwide. The effects of these micronutrient deficiencies alone and in combination on hematologic, biochemical and molecular indices of iron and VA status were investigated in a 2 x 2 randomized blocked study conducted in growing male Sprague-Dawley rats. From 3-8 wk of age, rats were fed one of four purified diets that were either adequate or restricted in iron (Fe) and adequate or marginal in VA: (+)Fe(+)VA, 20.3 and 0.367 micro g/g, respectively, denoted control diet; (-)Fe(+)VA, 3.34 and 0.405 micro g/g; (+)FeVA(m), 22.2 and 0.051 micro g/g; or (-)FeVA(m), 3.03 and 0.055 micro g/g. Weight-matched rats fed adequate micronutrients were included to control for possible confounding effects of Fe deficiency on growth and feed efficiency. Iron restriction reduced (P < 0.05) weight gain, feed efficiency, blood hemoglobin and hematocrit. Plasma and liver iron and plasma transferrin saturation were reduced by approximately 50%, whereas liver transferrin mRNA and protein and transferrin receptor mRNA were elevated, as was liver ferritin light-chain protein and light-chain mRNA. Liver heavy-chain ferritin mRNA, hemopexin, ceruloplasmin and cellular retinol-binding protein mRNA were not affected by iron or VA restriction. Although marginal VA deficiency did not exacerbate indices of poor iron status during iron deficiency, iron deficiency was associated with lower plasma retinol and elevated liver VA concentrations. These results are consistent with an impaired mobilization of liver retinol during iron deficiency as well as multiple alterations in iron metabolism.
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Affiliation(s)
- Yi Ning J Strube
- The Graduate Program in Nutrition and the Department of Nutritional Sciences, The Pennsylvania State University, University Park 16802, USA
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28
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Anderson GJ, Frazer DM, McKie AT, Vulpe CD. The ceruloplasmin homolog hephaestin and the control of intestinal iron absorption. Blood Cells Mol Dis 2002; 29:367-75. [PMID: 12547227 DOI: 10.1006/bcmd.2002.0576] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hephaestin is the gene affected in the sex-linked anemic (sla) mouse. These animals have a defect in the export of iron from intestinal enterocytes into the circulation and this implicates hephaestin in the basolateral transfer step of iron absorption. Hephaestin is homologous to the plasma copper-containing protein ceruloplasmin, and all residues involved in copper binding and disulfide bond formation in ceruloplasmin are conserved in hephaestin. Unlike ceruloplasmin, hephaestin is an integral membrane protein with a single trans-membrane domain. It is highly expressed throughout the small intestine, to a lesser extent in the colon, and at low levels in several other tissues. Surprisingly, most hephaestin appears to be located intracellularly in a perinuclear distribution. Like ceruloplasmin, hephaestin has a ferroxidase activity which is predicted to underlie its biological function. In addition, its expression is stimulated under iron deficient conditions. Analysis of the sla mouse has supported our model for the regulation of intestinal iron absorption whereby changes in systemic iron requirements alter the levels of basolateral transport components with subsequent regulation of brush border transport.
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Affiliation(s)
- Gregory J Anderson
- Iron Metabolism Laboratory, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Brisbane, Queensland 4029, Australia.
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29
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Abstract
Iron is vital for all living organisms but excess iron can be lethal because it facilitates free radical formation. Thus iron absorption is carefully regulated to maintain an equilibrium between absorption and body loss of iron. In countries where meat is a significant part of the diet, most body iron is derived from dietary heme because heme binds few of the dietary chelators that bind inorganic iron. Uptake of heme into enterocytes occurs as a metalloporphyrin in an endosomal process. Intracellular iron is released from heme by heme oxygenase to enter plasma as inorganic iron. Ferric iron is absorbed via a beta(3) integrin and mobilferrin pathway (IMP) which is unshared with other nutritional metals. Ferrous iron uptake is facilitated by a DMT-1 pathway which is shared with manganese. In the iron deficient gut, large quantities of both mobilferrin and DMT-1 are found in goblet cells and intraluminal mucins suggesting that they are secreted with mucin into the intestinal lumen to bind iron to facilitate uptake by the cells. In the cytoplasm, IMP and DMT associate in a large protein complex called paraferritin which serves as a ferrireductase. Paraferritin solublizes iron binding proteins and reduces iron to make iron available for production of iron containing proteins such as heme. Iron uptake by intestinal absorptive cells is regulated by the iron concentration within the cell. Except in hemochromatosis it remains in equilibrium with total body stores via transferrin receptors on the basolateral membrane of absorptive cells. Increased intracellular iron either up-regulates or satiates iron binding proteins on regulatory proteins to alter their location in the intestinal mucosa.
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Affiliation(s)
- Marcel E Conrad
- Gulf Coast MBCCOP, Suite 301, 3 Mobile Infirmary Circle, Mobile, AL 36607, USA.
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