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Baschant U, Fuqua BK, Ledesma-Colunga M, Vulpe CD, McLachlan S, Hofbauer LC, Lusis AJ, Rauner M. Effects of dietary iron deficiency or overload on bone: Dietary details matter. Bone 2024; 184:117092. [PMID: 38575048 DOI: 10.1016/j.bone.2024.117092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/28/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
PURPOSE Bone is susceptible to fluctuations in iron homeostasis, as both iron deficiency and overload are linked to poor bone strength in humans. In mice, however, inconsistent results have been reported, likely due to different diet setups or genetic backgrounds. Here, we assessed the effect of different high and low iron diets on bone in six inbred mouse strains (C57BL/6J, A/J, BALB/cJ, AKR/J, C3H/HeJ, and DBA/2J). METHODS Mice received a high (20,000 ppm) or low-iron diet (∼10 ppm) after weaning for 6-8 weeks. For C57BL/6J males, we used two dietary setups with similar amounts of iron, yet different nutritional compositions that were either richer ("TUD study") or poorer ("UCLA study") in minerals and vitamins. After sacrifice, liver, blood and bone parameters as well as bone turnover markers in the serum were analyzed. RESULTS Almost all mice on the UCLA study high iron diet had a significant decrease of cortical and trabecular bone mass accompanied by high bone resorption. Iron deficiency did not change bone microarchitecture or turnover in C57BL/6J, A/J, and DBA/2J mice, but increased trabecular bone mass in BALB/cJ, C3H/HeJ and AKR/J mice. In contrast to the UCLA study, male C57BL/6J mice in the TUD study did not display any changes in trabecular bone mass or turnover on high or low iron diet. However, cortical bone parameters were also decreased in TUD mice on the high iron diet. CONCLUSION Thus, these data show that cortical bone is more susceptible to iron overload than trabecular bone and highlight the importance of a nutrient-rich diet to potentially mitigate the negative effects of iron overload on bone.
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Affiliation(s)
- Ulrike Baschant
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Germany
| | - Brie K Fuqua
- Department of Medicine, Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Maria Ledesma-Colunga
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Germany
| | - Christopher D Vulpe
- Department of Physiological Sciences, University of Florida Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, USA
| | | | - Lorenz C Hofbauer
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Germany
| | - Aldons J Lusis
- Department of Medicine, Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Martina Rauner
- Department of Medicine III & Center for Healthy Aging, Technische Universität Dresden, Germany.
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2
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Helman SL, Zhou J, Fuqua BK, Lu Y, Collins JF, Chen H, Vulpe CD, Anderson GJ, Frazer DM. The biology of mammalian multi-copper ferroxidases. Biometals 2023; 36:263-281. [PMID: 35167013 PMCID: PMC9376197 DOI: 10.1007/s10534-022-00370-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 02/04/2022] [Indexed: 12/24/2022]
Abstract
The mammalian multicopper ferroxidases (MCFs) ceruloplasmin (CP), hephaestin (HEPH) and zyklopen (ZP) comprise a family of conserved enzymes that are essential for body iron homeostasis. Each of these enzymes contains six biosynthetically incorporated copper atoms which act as intermediate electron acceptors, and the oxidation of iron is associated with the four electron reduction of dioxygen to generate two water molecules. CP occurs in both a secreted and GPI-linked (membrane-bound) form, while HEPH and ZP each contain a single C-terminal transmembrane domain. These enzymes function to ensure the efficient oxidation of iron so that it can be effectively released from tissues via the iron export protein ferroportin and subsequently bound to the iron carrier protein transferrin in the blood. CP is particularly important in facilitating iron release from the liver and central nervous system, HEPH is the major MCF in the small intestine and is critical for dietary iron absorption, and ZP is important for normal hair development. CP and HEPH (and possibly ZP) function in multiple tissues. These proteins also play other (non-iron-related) physiological roles, but many of these are ill-defined. In addition to disrupting iron homeostasis, MCF dysfunction perturbs neurological and immune function, alters cancer susceptibility, and causes hair loss, but, despite their importance, how MCFs co-ordinately maintain body iron homeostasis and perform other functions remains incompletely understood.
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Affiliation(s)
- Sheridan L Helman
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jie Zhou
- Department of Physiological Sciences, University of Florida, Gainsville, FL, USA
| | - Brie K Fuqua
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Yan Lu
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Brisbane, QLD, 4006, Australia
- Mucosal Immunology Group, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James F Collins
- Food Science and Human Nutrition Department, University of Florida, Gainsville, FL, USA
| | - Huijun Chen
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Christopher D Vulpe
- Department of Physiological Sciences, University of Florida, Gainsville, FL, USA
| | - Gregory J Anderson
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Brisbane, QLD, 4006, Australia.
- School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, Australia.
| | - David M Frazer
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
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3
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Thummuri D, Khan S, Underwood PW, Zhang P, Wiegand J, Zhang X, Budamagunta V, Sobh A, Tagmount A, Loguinov A, Riner AN, Akki AS, Williamson E, Hromas R, Vulpe CD, Zheng G, Trevino JG, Zhou D. Overcoming Gemcitabine Resistance in Pancreatic Cancer Using the BCL-X L-Specific Degrader DT2216. Mol Cancer Ther 2022; 21:184-192. [PMID: 34667112 PMCID: PMC8742767 DOI: 10.1158/1535-7163.mct-21-0474] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/16/2021] [Accepted: 10/14/2021] [Indexed: 01/09/2023]
Abstract
Pancreatic cancer is the third most common cause of cancer-related deaths in the United States. Although gemcitabine is the standard of care for most patients with pancreatic cancer, its efficacy is limited by the development of resistance. This resistance may be attributable to the evasion of apoptosis caused by the overexpression of BCL-2 family antiapoptotic proteins. In this study, we investigated the role of BCL-XL in gemcitabine resistance to identify a combination therapy to more effectively treat pancreatic cancer. We used CRISPR-Cas9 screening to identify the key genes involved in gemcitabine resistance in pancreatic cancer. Pancreatic cancer cell dependencies on different BCL-2 family proteins and the efficacy of the combination of gemcitabine and DT2216 (a BCL-XL proteolysis targeting chimera or PROTAC) were determined by MTS, Annexin-V/PI, colony formation, and 3D tumor spheroid assays. The therapeutic efficacy of the combination was investigated in several patient-derived xenograft (PDX) mouse models of pancreatic cancer. We identified BCL-XL as a key mediator of gemcitabine resistance. The combination of gemcitabine and DT2216 synergistically induced cell death in multiple pancreatic cancer cell lines in vitro In vivo, the combination significantly inhibited tumor growth and prolonged the survival of tumor-bearing mice compared with the individual agents in pancreatic cancer PDX models. Their synergistic antitumor activity is attributable to DT2216-induced degradation of BCL-XL and concomitant suppression of MCL-1 by gemcitabine. Our results suggest that DT2216-mediated BCL-XL degradation augments the antitumor activity of gemcitabine and their combination could be more effective for pancreatic cancer treatment.
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Affiliation(s)
- Dinesh Thummuri
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Sajid Khan
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Patrick W Underwood
- Department of Surgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Peiyi Zhang
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Janet Wiegand
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Xuan Zhang
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Vivekananda Budamagunta
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Amin Sobh
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Abderrahmane Tagmount
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Alexander Loguinov
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Andrea N Riner
- Department of Surgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Ashwin S Akki
- Department of Pathology, College of Medicine, University of Florida, Gainesville, Florida
| | - Elizabeth Williamson
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Robert Hromas
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Christopher D Vulpe
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Guangrong Zheng
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Jose G Trevino
- Department of Surgery, College of Medicine, University of Florida, Gainesville, Florida
- Division of Surgical Oncology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Daohong Zhou
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida.
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4
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Helman SL, Wilkins SJ, McKeating DR, Perkins AV, Whibley PE, Cuffe JSM, Simmons DG, Fuqua BK, Vulpe CD, Wallace DF, O'Callaghan JL, Pelzer ES, Anderson GJ, Frazer DM. The Placental Ferroxidase Zyklopen Is Not Essential for Iron Transport to the Fetus in Mice. J Nutr 2021; 151:2541-2550. [PMID: 34114013 DOI: 10.1093/jn/nxab174] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/09/2021] [Accepted: 05/07/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The ferroxidase zyklopen (Zp) has been implicated in the placental transfer of iron to the fetus. However, the evidence for this is largely circumstantial. OBJECTIVES This study aimed to determine whether Zp is essential for placental iron transfer. METHODS A model was established using 8- to 12-wk-old pregnant C57BL/6 mice on standard rodent chow in which Zp was knocked out in the fetus and fetal components of the placenta. Zp was also disrupted in the entire placenta using global Zp knockout mice. Inductively coupled plasma MS was used to measure total fetal iron, an indicator of the amount of iron transferred by the placenta to the fetus, at embryonic day 18.5 of gestation. Iron transporter expression in the placenta was measured by Western blotting, and the expression of Hamp1, the gene encoding the iron regulatory hormone hepcidin, was determined in fetal liver by real-time PCR. RESULTS There was no change in the amount of iron transferred to the fetus when Zp was disrupted in either the fetal component of the placenta or the entire placenta. No compensatory changes in the expression of the iron transport proteins transferrin receptor 1 or ferroportin were observed, nor was there any change in fetal liver Hamp1 mRNA. Hephl1, the gene encoding Zp, was expressed mainly in the maternal decidua of the placenta and not in the nutrient-transporting syncytiotrophoblast. Disruption of Zp in the whole placenta resulted in a 26% increase in placental size (P < 0.01). CONCLUSIONS Our data indicate that Zp is not essential for the efficient transfer of iron to the fetus in mice and is localized predominantly in the maternal decidua. The increase in placental size observed when Zp is knocked out in the entire placenta suggests that this protein may play a role in placental development.
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Affiliation(s)
- Sheridan L Helman
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Herston, Australia.,Faculty of Medicine, The University of Queensland, St. Lucia, Australia
| | - Sarah J Wilkins
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Herston, Australia
| | - Daniel R McKeating
- School of Medical Science, Griffith University, Gold Coast Campus, Southport, Australia
| | - Anthony V Perkins
- School of Medical Science, Griffith University, Gold Coast Campus, Southport, Australia
| | - Page E Whibley
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Herston, Australia
| | - James S M Cuffe
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
| | - David G Simmons
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia
| | - Brie K Fuqua
- David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Christopher D Vulpe
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Daniel F Wallace
- School of Biomedical Sciences, Queensland University of Technology, Gardens Point, Australia
| | - Jessica L O'Callaghan
- School of Biomedical Sciences, Queensland University of Technology, Gardens Point, Australia
| | - Elise S Pelzer
- School of Biomedical Sciences, Queensland University of Technology, Gardens Point, Australia
| | - Gregory J Anderson
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Herston, Australia.,School of Chemistry and Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - David M Frazer
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Herston, Australia.,School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia.,School of Biomedical Sciences, Queensland University of Technology, Gardens Point, Australia
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5
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Lambert FN, Gracy HR, Gracy AJ, Yoon SH, Scott RW, Rincon DM, Vulpe CD. Effects of ultraviolet-filters on Daphnia magna development and endocrine-related gene expression. Aquat Toxicol 2021; 238:105915. [PMID: 34329859 DOI: 10.1016/j.aquatox.2021.105915] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 06/23/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Ultraviolet (UV) filters are emerging contaminants of concern that are widely spread throughout the aquatic environment. Many organic UV filters are endocrine disrupting compounds (EDCs) in vertebrates. However, few studies have assessed their effects on invertebrates. Molting, or the shedding of the exoskeleton, may be affected by exposure to these compounds in Arthropods (the largest phylum of invertebrates). Molting is necessary for growth and development and is regulated by an arthropod specific endocrine system, the ecdysteroid pathway. Alterations of this process by EDCs can result in improper development, reduced growth, and even death. We investigated the sublethal effects of chronic exposure to three organic UV filters (4-methylbenzylidene camphor (4MBC), octylmethoxycinnamate (OMC), and benzophenone-3 (BP3) in a crustacean, Daphnia magna, with particular emphasis on molting and development. We demonstrate that 4MBC, OMC, and BP3 affect development and long-term health in neonates of exposed parents at concentrations of 130 µg/L, 75 µg/L, and 166 µg/L, respectively. Additionally, the expression of endocrine-related genes (including ultraspiracle protein, usp) are significantly altered by 4MBC and BP3 exposure, which may relate to their developmental toxicity.
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Affiliation(s)
- F N Lambert
- Center for Environmental and Human Toxicology, University of Florida.
| | - H R Gracy
- Center for Environmental and Human Toxicology, University of Florida
| | - A J Gracy
- Center for Environmental and Human Toxicology, University of Florida
| | - S H Yoon
- Center for Environmental and Human Toxicology, University of Florida
| | - R W Scott
- Center for Environmental and Human Toxicology, University of Florida
| | - D M Rincon
- Center for Environmental and Human Toxicology, University of Florida
| | - C D Vulpe
- Center for Environmental and Human Toxicology, University of Florida
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6
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Besse L, Besse A, Stolze SC, Sobh A, Zaal EA, van der Ham AJ, Ruiz M, Phuyal S, Büchler L, Sathianathan M, Florea BI, Borén J, Ståhlman M, Huber J, Bolomsky A, Ludwig H, Hannich JT, Loguinov A, Everts B, Berkers CR, Pilon M, Farhan H, Vulpe CD, Overkleeft HS, Driessen C. Treatment with HIV-Protease Inhibitor Nelfinavir Identifies Membrane Lipid Composition and Fluidity as a Therapeutic Target in Advanced Multiple Myeloma. Cancer Res 2021; 81:4581-4593. [PMID: 34158378 DOI: 10.1158/0008-5472.can-20-3323] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/30/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022]
Abstract
The HIV-protease inhibitor nelfinavir has shown broad anticancer activity in various preclinical and clinical contexts. In patients with advanced, proteasome inhibitor (PI)-refractory multiple myeloma, nelfinavir-based therapy resulted in 65% partial response or better, suggesting that this may be a highly active chemotherapeutic option in this setting. The broad anticancer mechanism of action of nelfinavir implies that it interferes with fundamental aspects of cancer cell biology. We combined proteome-wide affinity-purification of nelfinavir-interacting proteins with genome-wide CRISPR/Cas9-based screening to identify protein partners that interact with nelfinavir in an activity-dependent manner alongside candidate genetic contributors affecting nelfinavir cytotoxicity. Nelfinavir had multiple activity-specific binding partners embedded in lipid bilayers of mitochondria and the endoplasmic reticulum. Nelfinavir affected the fluidity and composition of lipid-rich membranes, disrupted mitochondrial respiration, blocked vesicular transport, and affected the function of membrane-embedded drug efflux transporter ABCB1, triggering the integrated stress response. Sensitivity to nelfinavir was dependent on ADIPOR2, which maintains membrane fluidity by promoting fatty acid desaturation and incorporation into phospholipids. Supplementation with fatty acids prevented the nelfinavir-induced effect on mitochondrial metabolism, drug-efflux transporters, and stress-response activation. Conversely, depletion of fatty acids/cholesterol pools by the FDA-approved drug ezetimibe showed a synergistic anticancer activity with nelfinavir in vitro. These results identify the modification of lipid-rich membranes by nelfinavir as a novel mechanism of action to achieve broad anticancer activity, which may be suitable for the treatment of PI-refractory multiple myeloma. SIGNIFICANCE: Nelfinavir induces lipid bilayer stress in cellular organelles that disrupts mitochondrial respiration and transmembrane protein transport, resulting in broad anticancer activity via metabolic rewiring and activation of the unfolded protein response.
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Affiliation(s)
- Lenka Besse
- Laboratory of Experimental Oncology, Clinic for Medical Oncology and Hematology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
| | - Andrej Besse
- Laboratory of Experimental Oncology, Clinic for Medical Oncology and Hematology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Sara C Stolze
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Amin Sobh
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Esther A Zaal
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.,Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Alwin J van der Ham
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mario Ruiz
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Santosh Phuyal
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Lorina Büchler
- Laboratory of Experimental Oncology, Clinic for Medical Oncology and Hematology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Marc Sathianathan
- Laboratory of Experimental Oncology, Clinic for Medical Oncology and Hematology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Bogdan I Florea
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Jan Borén
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Julia Huber
- Department of Medicine I, Wilhelminen Cancer Research Institute, Klinik Ottakring, Vienna, Austria
| | - Arnold Bolomsky
- Department of Medicine I, Wilhelminen Cancer Research Institute, Klinik Ottakring, Vienna, Austria
| | - Heinz Ludwig
- Department of Medicine I, Wilhelminen Cancer Research Institute, Klinik Ottakring, Vienna, Austria
| | - J Thomas Hannich
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Alex Loguinov
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Bart Everts
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Celia R Berkers
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.,Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Marc Pilon
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Hesso Farhan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Institute of Pathophysiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christopher D Vulpe
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | | | - Christoph Driessen
- Laboratory of Experimental Oncology, Clinic for Medical Oncology and Hematology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
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Abstract
The use of genome editing tools is expanding our understanding of various human diseases by providing insight into gene-disease interactions. Despite the recognized role of toxicants in the development of human health issues and conditions, there is currently limited characterization of their mechanisms of action, and the application of CRISPR-based genome editing to the study of toxicants could help in the identification of novel gene-environment interactions. CRISPR-based functional screens enable identification of cellular mechanisms fundamental for response and susceptibility to a given toxicant. The aim of this review is to inform future directions in the application of CRISPR technologies in toxicological studies. We review and compare different types of CRISPR-based methods including pooled, anchored, combinatorial, and perturb-sequencing screens in vitro, in addition to pooled screenings in model organisms. © 2021 Wiley Periodicals LLC.
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Affiliation(s)
- Amin Sobh
- Department of Medicine, University of Florida Health Cancer Center, University of Florida, Gainesville, Florida
| | - Max Russo
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Christopher D Vulpe
- Department of Physiological Sciences, Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida
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8
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Mehinto AC, Thornton Hampton LM, Vidal-Dorsch DE, Garcia-Reyero N, Arick MA, Maruya KA, Lao W, Vulpe CD, Brown-Augustine M, Loguinov A, Bay SM. Transcriptomic response patterns of hornyhead turbot (Pleuronichthys verticalis) dosed with polychlorinated biphenyls and polybrominated diphenyl ethers. Comp Biochem Physiol Part D Genomics Proteomics 2021; 38:100822. [PMID: 33684654 DOI: 10.1016/j.cbd.2021.100822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/04/2020] [Accepted: 01/19/2021] [Indexed: 12/15/2022]
Abstract
To evaluate the impact of environmental contaminants on aquatic health, extensive surveys of fish populations have been conducted using bioaccumulation as an indicator of impairment. While these studies have reported mixtures of chemicals in fish tissues, the relationship between specific contaminants and observed adverse impacts remains poorly understood. The present study aimed to characterize the toxicological responses induced by persistent organic pollutants in wild-caught hornyhead turbot (P. verticalis). To do so, hornyhead turbot were interperitoneally injected with a single dose of PCB or PBDE congeners prepared using environmentally realistic mixture proportions. After 96-hour exposure, the livers were excised and analyzed using transcriptomic approaches and analytical chemistry. Concentrations of PCBs and PBDEs measured in the livers indicated clear differences across treatments, and congener profiles closely mirrored our expectations. Distinct gene profiles were characterized for PCB and PBDE exposed fish, with significant differences observed in the expression of genes associated with immune responses, endocrine-related functions, and lipid metabolism. Our findings highlight the key role that transcriptomics can play in monitoring programs to assess chemical-induced toxicity in heterogeneous group of fish (mixed gender and life stage) as is typically found during field surveys. Altogether, the present study provides further evidence of the potential of transcriptomic tools to improve aquatic health assessment and identify causative agents.
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Affiliation(s)
- Alvine C Mehinto
- Department of Toxicology, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA; Department of Chemistry, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA.
| | - Leah M Thornton Hampton
- Department of Toxicology, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA
| | - Doris E Vidal-Dorsch
- Department of Toxicology, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA
| | - Natàlia Garcia-Reyero
- Environmental Laboratory, US Army Engineer Research & Development Center, Vicksburg, MS 39180, USA
| | - Mark A Arick
- Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, Starkville, MS 39762, USA
| | - Keith A Maruya
- Department of Chemistry, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA
| | - Wenjian Lao
- Department of Chemistry, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA
| | - Christopher D Vulpe
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Marianna Brown-Augustine
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Alex Loguinov
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Steven M Bay
- Department of Toxicology, Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA
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9
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Sobh A, Loguinov A, Zhou J, Jenkitkasemwong S, Zeidan R, El Ahmadie N, Tagmount A, Knutson M, Fraenkel PG, Vulpe CD. Genetic screens reveal CCDC115 as a modulator of erythroid iron and heme trafficking. Am J Hematol 2020; 95:1085-1098. [PMID: 32510613 DOI: 10.1002/ajh.25899] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/27/2020] [Accepted: 05/31/2020] [Indexed: 12/26/2022]
Abstract
Transferrin-bound iron (TBI), the physiological circulating iron form, is acquired by cells through the transferrin receptor (TfR1) by endocytosis. In erythroid cells, most of the acquired iron is incorporated into heme in the mitochondria. Cellular trafficking of heme is indispensable for erythropoiesis and many other essential biological processes. Comprehensive elucidation of molecular pathways governing and regulating cellular iron acquisition and heme trafficking is required to better understand physiological and pathological processes affecting erythropoiesis. Here, we report the first genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screens in human erythroid cells to identify determinants of iron and heme uptake, as well as heme-mediated erythroid differentiation. We identified several candidate modulators of TBI acquisition including TfR1, indicating that our approach effectively revealed players mechanistically relevant to the process. Interestingly, components of the endocytic pathway were also revealed as potential determinants of transferrin acquisition. We deciphered a role for the vacuolar-type H+ - ATPase (V- ATPase) assembly factor coiled-coil domain containing 115 (CCDC115) in TBI uptake and validated this role in CCDC115 deficient K562 cells. Our screen in hemin-treated cells revealed perturbations leading to cellular adaptation to heme, including those corresponding to trafficking mechanisms and transcription factors potentiating erythroid differentiation. Pathway analysis indicated that endocytosis and vesicle acidification are key processes for heme trafficking in erythroid precursors. Furthermore, we provided evidence that CCDC115, which we identified as required for TBI uptake, is also involved in cellular heme distribution. This work demonstrates a previously unappreciated common intersection in trafficking of transferrin iron and heme in the endocytic pathway of erythroid cells.
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Affiliation(s)
- Amin Sobh
- Department of Nutritional Sciences & Toxicology, Comparative Biochemistry Program University of California Berkeley Berkeley California
- Department of Physiological Sceinces University of Florida Gainesville Florida
| | - Alex Loguinov
- Department of Physiological Sceinces University of Florida Gainesville Florida
| | - Jie Zhou
- Department of Physiological Sceinces University of Florida Gainesville Florida
- Department of Food Science and Human Nutrition University of Florida Gainesville Florida
| | - Supak Jenkitkasemwong
- Department of Food Science and Human Nutrition University of Florida Gainesville Florida
| | - Rola Zeidan
- Department of Physiological Sceinces University of Florida Gainesville Florida
| | - Nader El Ahmadie
- Department of Physiological Sceinces University of Florida Gainesville Florida
| | | | - Mitchell Knutson
- Department of Food Science and Human Nutrition University of Florida Gainesville Florida
| | - Paula G. Fraenkel
- Division of Hematology/Oncology and Cancer Research Institute Beth Israel Deaconess Medical Center Boston Massachusetts
- Department of Medicine Harvard Medical School Boston Massachusetts
- Oncology Research and Development, Sanofi Cambridge Massachusetts
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Sharma P, Reichert M, Lu Y, Markello TC, Adams DR, Steinbach PJ, Fuqua BK, Parisi X, Kaler SG, Vulpe CD, Anderson GJ, Gahl WA, Malicdan MCV. Biallelic HEPHL1 variants impair ferroxidase activity and cause an abnormal hair phenotype. PLoS Genet 2019; 15:e1008143. [PMID: 31125343 PMCID: PMC6534290 DOI: 10.1371/journal.pgen.1008143] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 04/16/2019] [Indexed: 11/18/2022] Open
Abstract
Maintenance of the correct redox status of iron is functionally important for critical biological processes. Multicopper ferroxidases play an important role in oxidizing ferrous iron, released from the cells, into ferric iron, which is subsequently distributed by transferrin. Two well-characterized ferroxidases, ceruloplasmin (CP) and hephaestin (HEPH) facilitate this reaction in different tissues. Recently, a novel ferroxidase, Hephaestin like 1 (HEPHL1), also known as zyklopen, was identified. Here we report a child with compound heterozygous mutations in HEPHL1 (NM_001098672) who presented with abnormal hair (pili torti and trichorrhexis nodosa) and cognitive dysfunction. The maternal missense mutation affected mRNA splicing, leading to skipping of exon 5 and causing an in-frame deletion of 85 amino acids (c.809_1063del; p.Leu271_ala355del). The paternal mutation (c.3176T>C; p.Met1059Thr) changed a highly conserved methionine that is part of a typical type I copper binding site in HEPHL1. We demonstrated that HEPHL1 has ferroxidase activity and that the patient's two mutations exhibited loss of this ferroxidase activity. Consistent with these findings, the patient's fibroblasts accumulated intracellular iron and exhibited reduced activity of the copper-dependent enzyme, lysyl oxidase. These results suggest that the patient's biallelic variants are loss-of-function mutations. Hence, we generated a Hephl1 knockout mouse model that was viable and had curly whiskers, consistent with the hair phenotype in our patient. These results enhance our understanding of the function of HEPHL1 and implicate altered ferroxidase activity in hair growth and hair disorders.
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Affiliation(s)
- Prashant Sharma
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marie Reichert
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yan Lu
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Thomas C. Markello
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland Bethesda, Maryland, United States of America
| | - David R. Adams
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter J. Steinbach
- Center for Molecular Modeling, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Brie K. Fuqua
- Department of Medicine, University of California, Los Angeles, United States of America
| | - Xenia Parisi
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephen G. Kaler
- Section on Translational Neuroscience, Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Christopher D. Vulpe
- Center for Environmental and Human Toxicology, Department of Physiological Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Gregory J. Anderson
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - William A. Gahl
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland Bethesda, Maryland, United States of America
| | - May Christine V. Malicdan
- NIH Undiagnosed Diseases Program, Common Fund, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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11
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Luo H, Sobh A, Vulpe CD, Brewer E, Dovat S, Qiu Y, Huang S. HOX Loci Focused CRISPR/sgRNA Library Screening Identifying Critical CTCF Boundaries. J Vis Exp 2019:10.3791/59382. [PMID: 30985763 PMCID: PMC7607627 DOI: 10.3791/59382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
CCCTC-binding factor (CTCF)-mediated stable topologically associating domains (TADs) play a critical role in constraining interactions of DNA elements that are located in neighboring TADs. CTCF plays an important role in regulating the spatial and temporal expression of HOX genes that control embryonic development, body patterning, hematopoiesis, and leukemogenesis. However, it remains largely unknown whether and how HOX loci associated CTCF boundaries regulate chromatin organization and HOX gene expression. In the current protocol, a specific sgRNA pooled library targeting all CTCF binding sites in the HOXA/B/C/D loci has been generated to examine the effects of disrupting CTCF-associated chromatin boundaries on TAD formation and HOX gene expression. Through CRISPR-Cas9 genetic screening, the CTCF binding site located between HOXA7/HOXA9 genes (CBS7/9) has been identified as a critical regulator of oncogenic chromatin domain, as well as being important for maintaining ectopic HOX gene expression patterns in MLL-rearranged acute myeloid leukemia (AML). Thus, this sgRNA library screening approach provides novel insights into CTCF mediated genome organization in specific gene loci and also provides a basis for the functional characterization of the annotated genetic regulatory elements, both coding and noncoding, during normal biological processes in the post-human genome project era.
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Affiliation(s)
- Huacheng Luo
- Department of Pediatrics, Pennsylvania State University College of Medicine;
| | - Amin Sobh
- Department of Physiological Sciences, University of Florida
| | | | - Edmond Brewer
- Department of Pediatrics, Pennsylvania State University College of Medicine
| | - Sinisa Dovat
- Department of Pediatrics, Pennsylvania State University College of Medicine
| | - Yi Qiu
- Department of Anatomy and Cell Biology, University of Florida
| | - Suming Huang
- Department of Pediatrics, Pennsylvania State University College of Medicine;
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12
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Gust KA, Chaitankar V, Ghosh P, Wilbanks MS, Chen X, Barker ND, Pham D, Scanlan LD, Rawat A, Talent LG, Quinn MJ, Vulpe CD, Elasri MO, Johnson MS, Perkins EJ, McFarland CA. Multiple environmental stressors induce complex transcriptomic responses indicative of phenotypic outcomes in Western fence lizard. BMC Genomics 2018; 19:877. [PMID: 30518325 PMCID: PMC6282355 DOI: 10.1186/s12864-018-5270-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/19/2018] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND The health and resilience of species in natural environments is increasingly challenged by complex anthropogenic stressor combinations including climate change, habitat encroachment, and chemical contamination. To better understand impacts of these stressors we examined the individual- and combined-stressor impacts of malaria infection, food limitation, and 2,4,6-trinitrotoluene (TNT) exposures on gene expression in livers of Western fence lizards (WFL, Sceloporus occidentalis) using custom WFL transcriptome-based microarrays. RESULTS Computational analysis including annotation enrichment and correlation analysis identified putative functional mechanisms linking transcript expression and toxicological phenotypes. TNT exposure increased transcript expression for genes involved in erythropoiesis, potentially in response to TNT-induced anemia and/or methemoglobinemia and caused dose-specific effects on genes involved in lipid and overall energy metabolism consistent with a hormesis response of growth stimulation at low doses and adverse decreases in lizard growth at high doses. Functional enrichment results were indicative of inhibited potential for lipid mobilization and catabolism in TNT exposures which corresponded with increased inguinal fat weights and was suggestive of a decreased overall energy budget. Malaria infection elicited enriched expression of multiple immune-related functions likely corresponding to increased white blood cell (WBC) counts. Food limitation alone enriched functions related to cellular energy production and decreased expression of immune responses consistent with a decrease in WBC levels. CONCLUSIONS Despite these findings, the lizards demonstrated immune resilience to malaria infection under food limitation with transcriptional results indicating a fully competent immune response to malaria, even under bio-energetic constraints. Interestingly, both TNT and malaria individually increased transcriptional expression of immune-related genes and increased overall WBC concentrations in blood; responses that were retained in the TNT x malaria combined exposure. The results demonstrate complex and sometimes unexpected responses to multiple stressors where the lizards displayed remarkable resiliency to the stressor combinations investigated.
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Affiliation(s)
- Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, 39180, USA.
| | - Vijender Chaitankar
- National Institute of Health - National Heart, Lung, and Blood Institute, Bethesda, MD, 20892, USA
| | - Preetam Ghosh
- Virginia Commonwealth University, School of Engineering, Richmond, VA, 23284, USA
| | - Mitchell S Wilbanks
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, 39180, USA
| | - Xianfeng Chen
- IFXworks LLC, 2915 Columbia Pike, Arlington, VA, 22204, USA
| | | | - Don Pham
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA, 94720, USA.,Carlsbad Unified School District, Carlsbad, CA, 92009, USA
| | - Leona D Scanlan
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA, 94720, USA.,Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, CA, 95812, USA
| | - Arun Rawat
- Sidra Medicine, Education City (North Campus), Doha, 26999, Qatar
| | - Larry G Talent
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Michael J Quinn
- U.S. Army Public Health Center, Aberdeen Proving Ground, Aberdeen, MD, 21010, USA
| | - Christopher D Vulpe
- College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mohamed O Elasri
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406-5018, USA
| | - Mark S Johnson
- U.S. Army Public Health Center, Aberdeen Proving Ground, Aberdeen, MD, 21010, USA
| | - Edward J Perkins
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, 39180, USA
| | - Craig A McFarland
- U.S. Army Public Health Center, Aberdeen Proving Ground, Aberdeen, MD, 21010, USA
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13
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Lee SM, Loguinov A, Fleming RE, Vulpe CD. Effects of strain and age on hepatic gene expression profiles in murine models of HFE-associated hereditary hemochromatosis. Genes Nutr 2014; 10:443. [PMID: 25427953 DOI: 10.1007/s12263-014-0443-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/15/2014] [Indexed: 12/20/2022]
Abstract
Hereditary hemochromatosis is an iron overload disorder most commonly caused by a defect in the HFE gene. While the genetic defect is highly prevalent, the majority of individuals do not develop clinically significant iron overload, suggesting the importance of genetic modifiers. Murine hfe knockout models have demonstrated that strain background has a strong effect on the severity of iron loading. We noted that hepatic iron loading in hfe-/- mice occurs primarily over the first postnatal weeks (loading phase) followed by a timeframe of relatively static iron concentrations (plateau phase). We thus evaluated the effects of background strain and of age on hepatic gene expression in Hfe knockout mice (hfe-/-). Hepatic gene expression profiles were examined using cDNA microarrays in 4- and 8-week-old hfe-/- and wild-type mice on two different genetic backgrounds, C57BL/6J (C57) and AKR/J (AKR). Genes differentially regulated in all hfe-/- mice groups, compared with wild-type mice, including those involved in cell survival, stress and damage responses and lipid metabolism. AKR strain-specific changes in lipid metabolism genes and C57 strain-specific changes in cell adhesion and extracellular matrix protein genes were detected in hfe-/- mice. Mouse strain and age are each significantly associated with hepatic gene expression profiles in hfe-/- mice. These affects may underlie or reflect differences in iron loading in these mice.
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Affiliation(s)
- Seung-Min Lee
- Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, South Korea,
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14
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Mehinto AC, Prucha MS, Colli-Dula RC, Kroll KJ, Lavelle CM, Barber DS, Vulpe CD, Denslow ND. Gene networks and toxicity pathways induced by acute cadmium exposure in adult largemouth bass (Micropterus salmoides). Aquat Toxicol 2014; 152:186-194. [PMID: 24794047 DOI: 10.1016/j.aquatox.2014.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 04/02/2014] [Accepted: 04/05/2014] [Indexed: 06/03/2023]
Abstract
Cadmium is a heavy metal that can accumulate to toxic levels in the environment leading to detrimental effects in animals and humans including kidney, liver and lung injuries. Using a transcriptomics approach, genes and cellular pathways affected by a low dose of cadmium were investigated. Adult largemouth bass were intraperitoneally injected with 20μg/kg of cadmium chloride (mean exposure level - 2.6μg of cadmium per fish) and microarray analyses were conducted in the liver and testis 48h after injection. Transcriptomic profiles identified in response to cadmium exposure were tissue-specific with the most differential expression changes found in the liver tissues, which also contained much higher levels of cadmium than the testis. Acute exposure to a low dose of cadmium induced oxidative stress response and oxidative damage pathways in the liver. The mRNA levels of antioxidants such as catalase increased and numerous transcripts related to DNA damage and DNA repair were significantly altered. Hepatic mRNA levels of metallothionein, a molecular marker of metal exposure, did not increase significantly after 48h exposure. Carbohydrate metabolic pathways were also disrupted with hepatic transcripts such as UDP-glucose, pyrophosphorylase 2, and sorbitol dehydrogenase highly induced. Both tissues exhibited a disruption of steroid signaling pathways. In the testis, estrogen receptor beta and transcripts linked to cholesterol metabolism were suppressed. On the contrary, genes involved in cholesterol metabolism were highly increased in the liver including genes encoding for the rate limiting steroidogenic acute regulatory protein and the catalytic enzyme 7-dehydrocholesterol reductase. Integration of the transcriptomic data using functional enrichment analyses revealed a number of enriched gene networks associated with previously reported adverse outcomes of cadmium exposure such as liver toxicity and impaired reproduction.
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Affiliation(s)
- Alvine C Mehinto
- Southern California Coastal Water Research Project, Costa Mesa, CA 92626, United States; Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States.
| | - Melinda S Prucha
- Department of Human Genetics, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, United States; Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
| | - Reyna C Colli-Dula
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
| | - Kevin J Kroll
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
| | - Candice M Lavelle
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
| | - David S Barber
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
| | - Christopher D Vulpe
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720, United States
| | - Nancy D Denslow
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611, United States
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15
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Xia T, Hamilton RF, Bonner JC, Crandall ED, Elder A, Fazlollahi F, Girtsman TA, Kim K, Mitra S, Ntim SA, Orr G, Tagmount M, Taylor AJ, Telesca D, Tolic A, Vulpe CD, Walker AJ, Wang X, Witzmann FA, Wu N, Xie Y, Zink JI, Nel A, Holian A. Interlaboratory evaluation of in vitro cytotoxicity and inflammatory responses to engineered nanomaterials: the NIEHS Nano GO Consortium. Environ Health Perspect 2013; 121:683-90. [PMID: 23649538 PMCID: PMC3672931 DOI: 10.1289/ehp.1306561] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 04/01/2013] [Indexed: 05/21/2023]
Abstract
BACKGROUND Differences in interlaboratory research protocols contribute to the conflicting data in the literature regarding engineered nanomaterial (ENM) bioactivity. OBJECTIVES Grantees of a National Institute of Health Sciences (NIEHS)-funded consortium program performed two phases of in vitro testing with selected ENMs in an effort to identify and minimize sources of variability. METHODS Consortium program participants (CPPs) conducted ENM bioactivity evaluations on zinc oxide (ZnO), three forms of titanium dioxide (TiO2), and three forms of multiwalled carbon nanotubes (MWCNTs). In addition, CPPs performed bioassays using three mammalian cell lines (BEAS-2B, RLE-6TN, and THP-1) selected in order to cover two different species (rat and human), two different lung epithelial cells (alveolar type II and bronchial epithelial cells), and two different cell types (epithelial cells and macrophages). CPPs also measured cytotoxicity in all cell types while measuring inflammasome activation [interleukin-1β (IL-1β) release] using only THP-1 cells. RESULTS The overall in vitro toxicity profiles of ENM were as follows: ZnO was cytotoxic to all cell types at ≥ 50 μg/mL, but did not induce IL-1β. TiO2 was not cytotoxic except for the nanobelt form, which was cytotoxic and induced significant IL-1β production in THP-1 cells. MWCNTs did not produce cytotoxicity, but stimulated lower levels of IL-1β production in THP-1 cells, with the original MWCNT producing the most IL-1β. CONCLUSIONS The results provide justification for the inclusion of mechanism-linked bioactivity assays along with traditional cytotoxicity assays for in vitro screening. In addition, the results suggest that conducting studies with multiple relevant cell types to avoid false-negative outcomes is critical for accurate evaluation of ENM bioactivity.
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Affiliation(s)
- Tian Xia
- Department of Medicine, Division of NanoMedicine, Center for Environmental Implications of Nanotechnology, California Nanosystems Institute, University of California at Los Angeles, Los Angeles, California, USA
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16
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Abstract
Intestinal iron absorption is a critical process for maintaining body iron levels within the optimal physiological range. Iron in the diet is found in a wide variety of forms, but the absorption of non-heme iron is best understood. Most of this iron is moved across the enterocyte brush border membrane by the iron transporter divalent metal-ion transporter 1, a process enhanced by the prior reduction of the iron by duodenal cytochrome B and possibly other reductases. Enterocyte iron is exported to the blood via ferroportin 1 on the basolateral membrane. This transporter acts in partnership with the ferroxidase hephaestin that oxidizes exported ferrous iron to facilitate its binding to plasma transferrin. Iron absorption is controlled by a complex network of systemic and local influences. The liver-derived peptide hepcidin binds to ferroportin, leading to its internalization and a reduction in absorption. Hepcidin expression in turn responds to body iron demands and the BMP-SMAD signaling pathway plays a key role in this process. The levels of iron and oxygen in the enterocyte also exert important influences on iron absorption. Disturbances in the regulation of iron absorption are responsible for both iron loading and iron deficiency disorders in humans.
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Affiliation(s)
- Brie K Fuqua
- Iron Metabolism Laboratory, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
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17
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Ren X, Aleshin M, Jo WJ, Dills R, Kalman DA, Vulpe CD, Smith MT, Zhang L. Involvement of N-6 adenine-specific DNA methyltransferase 1 (N6AMT1) in arsenic biomethylation and its role in arsenic-induced toxicity. Environ Health Perspect 2011; 119:771-7. [PMID: 21193388 PMCID: PMC3114810 DOI: 10.1289/ehp.1002733] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 12/29/2010] [Indexed: 05/03/2023]
Abstract
BACKGROUND In humans, inorganic arsenic (iAs) is metabolized to methylated arsenical species in a multistep process mainly mediated by arsenic (+3 oxidation state) methyltransferase (AS3MT). Among these metabolites is monomethylarsonous acid (MMAIII), the most toxic arsenic species. A recent study in As3mt-knockout mice suggests that unidentified methyltransferases could be involved in alternative iAs methylation pathways. We found that yeast deletion mutants lacking MTQ2 were highly resistant to iAs exposure. The human ortholog of the yeast MTQ2 is N-6 adenine-specific DNA methyltransferase 1 (N6AMT1), encoding a putative methyltransferase. OBJECTIVE We investigated the potential role of N6AMT1 in arsenic-induced toxicity. METHODS We measured and compared the cytotoxicity induced by arsenicals and their metabolic profiles using inductively coupled plasma-mass spectrometry in UROtsa human urothelial cells with enhanced N6AMT1 expression and UROtsa vector control cells treated with different concentrations of either iAsIII or MMAIII. RESULTS N6AMT1 was able to convert MMAIII to the less toxic dimethylarsonic acid (DMA) when overexpressed in UROtsa cells. The enhanced expression of N6AMT1 in UROtsa cells decreased cytotoxicity of both iAsIII and MMAIII. Moreover, N6AMT1 is expressed in many human tissues at variable levels, although at levels lower than those of AS3MT, supporting a potential participation in arsenic metabolism in vivo. CONCLUSIONS Considering that MMAIII is the most toxic arsenical, our data suggest that N6AMT1 has a significant role in determining susceptibility to arsenic toxicity and carcinogenicity because of its specific activity in methylating MMAIII to DMA and other unknown mechanisms.
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Affiliation(s)
- Xuefeng Ren
- Genes and Environment Laboratory, Division of Environmental Health Sciences, School of Public Health and
| | - Maria Aleshin
- Genes and Environment Laboratory, Division of Environmental Health Sciences, School of Public Health and
| | - William J. Jo
- Department of Nutritional Sciences and Toxicology, University of California–Berkeley, Berkeley, California, USA
| | - Russel Dills
- Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA
| | - David A. Kalman
- Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA
| | - Christopher D. Vulpe
- Department of Nutritional Sciences and Toxicology, University of California–Berkeley, Berkeley, California, USA
| | - Martyn T. Smith
- Genes and Environment Laboratory, Division of Environmental Health Sciences, School of Public Health and
| | - Luoping Zhang
- Genes and Environment Laboratory, Division of Environmental Health Sciences, School of Public Health and
- Address correspondence to L. Zhang, School of Public Health, University of California–Berkeley, B84 Hildebrand Hall MC #7356, Berkeley, CA 94720 USA. Telephone: (510) 643-5189. Fax: (510) 642-0427. E-mail:
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18
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Connon RE, Beggel S, D'Abronzo LS, Geist JP, Pfeiff J, Loguinov AV, Vulpe CD, Werner I. Linking molecular biomarkers with higher level condition indicators to identify effects of copper exposures on the endangered delta smelt (Hypomesus transpacificus). Environ Toxicol Chem 2011; 30:290-300. [PMID: 21072851 DOI: 10.1002/etc.400] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The delta smelt (Hypomesus transpacificus) is an endangered pelagic fish species endemic to the Sacramento-San Joaquin estuary (CA, USA), and considered an indicator of ecosystem health. Copper is a contaminant of concern in Californian waterways that may affect the development and survival of this endangered species. The experimental combination of molecular biomarkers with higher level effects may allow for interpretation of responses in a functional context that can be used to predict detrimental outcomes caused by exposure. A delta smelt microarray was developed and applied to screen for candidate molecular biomarkers that may be used in monitoring programs. Functional classifications of microarray responses were used along with quantitative polymerase chain reaction determining effects upon neuromuscular, digestive, and immune responses in Cu-exposed delta smelt. Differences in sensitivity were measured between juveniles and larvae (median lethal concentration = 25.2 and 80.4 µg/L Cu(2+), respectively). Swimming velocity declined with higher exposure concentrations in a dose-dependent manner (r = -0.911, p < 0.05), though was not statistically significant to controls. Genes encoding for aspartoacylase, hemopexin, α-actin, and calcium regulation proteins were significantly affected by exposure and were functionally interpreted with measured swimming responses. Effects on digestion were measured by upregulation of chitinase and downregulation of amylase, whereas downregulation of tumor necrosis factor indicated a probable compromised immune system. Results from this study, and many others, support the use of functionally characterized molecular biomarkers to assess effects of contaminants in field scenarios. We thus propose that to attribute environmental relevance to molecular biomarkers, research should concentrate on their application in field studies with the aim of assisting monitoring programs.
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Affiliation(s)
- Richard E Connon
- School of Veterinary Medicine, University of California, Davis, California, USA.
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Lewinski NA, Zhu H, Jo HJ, Pham D, Kamath RR, Ouyang CR, Vulpe CD, Colvin VL, Drezek RA. Quantification of water solubilized CdSe/ZnS quantum dots in Daphnia magna. Environ Sci Technol 2010; 44:1841-1846. [PMID: 20131897 DOI: 10.1021/es902728a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The relative transparency of Daphnia magna (daphnia) and the unique optical properties of quantum dots (QDs) were paired to study the accumulation potential and surface coating effects on uptake of amphiphilic polymer coated CdSe/ZnS QDs. Fluorescence confocal laser scanning microscopy was used to visualize and spectrally distinguish QDs from competing autofluorescent signals arising from the daphnia themselves and their food sources. QDs were found to accumulate within the digestive tracts of daphnia, as well as, in some cases, adhere to the carapace, antennae, and thoracic appendages. After 48 h of gut clearance with and without feeding, QD fluorescence signal was still apparent in the digestive tracts of daphnia, and inductively coupled plasma mass spectrometry (ICP-MS) measurements confirmed that 36-53% of the initial uptake was retained. As surface charge and pegylation can influence the uptake of nanoparticles, uptake of QDs coated with two different amphililic polymers and their polyethylene glycol (PEG) coated counterparts was also examined. Fluorescence microscopy and ICP-MS measurements revealed differences in uptake after 24 h of exposure which were attributed to particle surface coating and stability.
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Connon RE, Geist J, Pfeiff J, Loguinov AV, D'Abronzo LS, Wintz H, Vulpe CD, Werner I. Linking mechanistic and behavioral responses to sublethal esfenvalerate exposure in the endangered delta smelt; Hypomesus transpacificus (Fam. Osmeridae). BMC Genomics 2009; 10:608. [PMID: 20003521 PMCID: PMC2806348 DOI: 10.1186/1471-2164-10-608] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 12/15/2009] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The delta smelt (Hypomesus transpacificus) is a pelagic fish species listed as endangered under both the USA Federal and Californian State Endangered Species Acts and considered an indicator of ecosystem health in its habitat range, which is limited to the Sacramento-San Joaquin estuary in California, USA. Anthropogenic contaminants are one of multiple stressors affecting this system, and among them, current-use insecticides are of major concern. Interrogative tools are required to successfully monitor effects of contaminants on the delta smelt, and to research potential causes of population decline in this species. We have created a microarray to investigate genome-wide effects of potentially causative stressors, and applied this tool to assess effects of the pyrethroid insecticide esfenvalerate on larval delta smelt. Selected genes were further investigated as molecular biomarkers using quantitative PCR analyses. RESULTS Exposure to esfenvalerate affected swimming behavior of larval delta smelt at concentrations as low as 0.0625 mug.L-1, and significant differences in expression were measured in genes involved in neuromuscular activity. Alterations in the expression of genes associated with immune responses, along with apoptosis, redox, osmotic stress, detoxification, and growth and development appear to have been invoked by esfenvalerate exposure. Swimming impairment correlated significantly with expression of aspartoacylase (ASPA), an enzyme involved in brain cell function and associated with numerous human diseases. Selected genes were investigated for their use as molecular biomarkers, and strong links were determined between measured downregulation in ASPA and observed behavioral responses in fish exposed to environmentally relevant pyrethroid concentrations. CONCLUSIONS The results of this study show that microarray technology is a useful approach in screening for, and generation of molecular biomarkers in endangered, non-model organisms, identifying specific genes that can be directly linked with sublethal toxicological endpoints; such as changes in expression levels of neuromuscular genes resulting in measurable swimming impairments. The developed microarrays were successfully applied on larval fish exposed to esfenvalerate, a known contaminant of the Sacramento-San Joaquin estuary, and has permitted the identification of specific biomarkers which could provide insight into the factors contributing to delta smelt population decline.
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Affiliation(s)
- Richard E Connon
- School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California, Davis, California 95616, USA
| | - Juergen Geist
- School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California, Davis, California 95616, USA
- Unit of Functional Aquatic Ecology and Fish Biology, Department of Animal Science, Technische Universität München, D-85350 Freising, Germany
| | - Janice Pfeiff
- School of Veterinary Medicine, Molecular Biosciences, University of California, Davis, California 95616, USA
| | - Alexander V Loguinov
- School of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Leandro S D'Abronzo
- School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California, Davis, California 95616, USA
| | - Henri Wintz
- School of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
- Biorad Laboratories, Life Science Research, Hercules, California, USA
| | - Christopher D Vulpe
- School of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Inge Werner
- School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California, Davis, California 95616, USA
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Abstract
Iron is essential for basic cellular processes but is toxic when present in excess. Consequently, iron transport into and out of cells is tightly regulated. Most iron is delivered to cells bound to plasma transferrin via a process that involves transferrin receptor 1, divalent metal-ion transporter 1 and several other proteins. Non-transferrin-bound iron can also be taken up efficiently by cells, although the mechanism is poorly understood. Cells can divest themselves of iron via the iron export protein ferroportin in conjunction with an iron oxidase. The linking of an oxidoreductase to a membrane permease is a common theme in membrane iron transport. At the systemic level, iron transport is regulated by the liver-derived peptide hepcidin which acts on ferroportin to control iron release to the plasma.
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Affiliation(s)
- Gregory Jon Anderson
- Iron Metabolism Laboratory, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, QLD, Australia.
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Petrak J, Ivanek R, Toman O, Cmejla R, Cmejlova J, Vyoral D, Zivny J, Vulpe CD. Déjà vu in proteomics. A hit parade of repeatedly identified differentially expressed proteins. Proteomics 2008; 8:1744-9. [PMID: 18442176 DOI: 10.1002/pmic.200700919] [Citation(s) in RCA: 292] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
After reading many 2-DE-based articles featuring lists of the differentially expressed proteins, one starts experiencing a disturbing déjà vu. The same proteins seem to predominate regardless of the experiment, tissue or species. To quantify the occurrence of individual differentially expressed proteins in 2-DE experiment reports, we compiled the identities of differentially expressed proteins identified in human, mouse, and rat tissues published in three recent volumes of Proteomics and calculated the appearance of the most predominant proteins in the dataset. The most frequently identified protein is a highly abundant glycolytic enzyme enolase 1, differentially expressed in nearly every third experiment on both human and rodent tissues. Heat-shock protein 27 (HSP27) and heat-shock protein 60 (HSP60) were differentially expressed in about 30 percent of human and rodent samples, respectively. Considering protein families as units, keratins and peroxiredoxins are the most frequently identified molecules, with at least one member of the group being differentially expressed in about 40 percent of all experiments. We suggest that the frequent identification of these proteins must be considered in the interpretation of any 2-DE studies. We consider if these commonly observed changes represent common cellular stress responses or are a reflection of the technical limitations of 2-DE.
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Affiliation(s)
- Jiri Petrak
- Institute of Hematology and Blood Transfusion, Prague, Czech Republic.
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23
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Petrak J, Myslivcova D, Man P, Cmejla R, Cmejlova J, Vyoral D, Elleder M, Vulpe CD. Proteomic analysis of hepatic iron overload in mice suggests dysregulation of urea cycle, impairment of fatty acid oxidation, and changes in the methylation cycle. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1490-8. [PMID: 17307722 DOI: 10.1152/ajpgi.00455.2006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Liver iron overload can be found in hereditary hemochromatosis, chronic liver diseases such as alcoholic liver disease, and chronic viral hepatitis or secondary to repeated blood transfusions. The excess iron promotes liver damage, including fibrosis, cirrhosis, and hepatocellular carcinoma. Despite significant research effort, we remain largely ignorant of the cellular consequences of liver iron overload and the cellular processes that result in the observed pathological changes. In addition, the variability in outcome and the compensatory response that likely modulates the effect of increased iron levels are not understood. To provide insight into these critical questions, we undertook a study to determine the consequences of iron overload on protein levels in liver using a proteomic approach. Using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) combined with matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), we studied hepatic iron overload induced by carbonyl iron-rich diet in mice and identified 30 liver proteins whose quantity changes in condition of excess liver iron. Among the identified proteins were enzymes involved in several important metabolic pathways, namely the urea cycle, fatty acid oxidation, and the methylation cycle. This pattern of changes likely reflects compensatory and pathological changes associated with liver iron overload and provides a window into these processes.
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Affiliation(s)
- Jiri Petrak
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic.
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24
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Petrak J, Myslivcova D, Halada P, Cmejla R, Cmejlova J, Vyoral D, Vulpe CD. Iron-independent specific protein expression pattern in the liver of HFE-deficient mice. Int J Biochem Cell Biol 2007; 39:1006-15. [PMID: 17376729 DOI: 10.1016/j.biocel.2007.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 01/19/2007] [Accepted: 01/22/2007] [Indexed: 12/01/2022]
Abstract
Hereditary hemochromatosis type I is an autosomal-recessive iron overload disease associated with a mutation in HFE gene. The most common mutation, C282Y, disrupts the disulfide bond necessary for the association of HFE with beta-2-microglobulin and abrogates cell surface HFE expression. HFE-deficient mice develop iron overload indicating a central role of the protein in the pathogenesis of hereditary hemochromatosis type I. However, despite significant effort, the role of the HFE protein in iron metabolism is still unknown. To shed a light on the molecular mechanism of HFE-related hemochromatosis we studied protein expression changes elicited by HFE-deficiency in the liver which is the organ critical for the regulation of iron metabolism. We undertook a proteomic study comparing protein expression in the liver of HFE deficient mice with control animals. We compared HFE-deficient animals with control animals with identical iron levels obtained by dietary treatment to identify changes specific to HFE deficiency rather than iron loading. We found 11 proteins that were differentially expressed in the HFE-deficient liver using two-dimensional electrophoresis and mass spectrometry identification. Of particular interest were urinary proteins 1, 2 and 6, glutathione-S-transferase P1, selenium binding protein 2, sarcosine dehydrogenase and thioredoxin-like protein 2. Our data suggest possible involvement of lipocalins, TNF-alpha signaling and PPAR alpha regulatory pathway in the pathogenesis of hereditary hemochromatosis and suggest future targeted research addressing the roles of the identified candidate genes in the molecular mechanism of hereditary hemochromatosis.
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Affiliation(s)
- Jiri Petrak
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic.
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25
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Lee S, Lim V, Vulpe CD. Strain specific modulation of tissue iron content and HFE gene expression in mice. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a194-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Seung‐Min Lee
- Nutritional Sciences and ToxicologyUniversity of California at BerkeleyMorgan Hall 244BerkeleyCA94720‐3104
| | - Vanessa Lim
- Nutritional Sciences and ToxicologyUniversity of California at BerkeleyMorgan Hall 244BerkeleyCA94720‐3104
| | - Christopher D Vulpe
- Nutritional Sciences and ToxicologyUniversity of California at BerkeleyMorgan Hall 244BerkeleyCA94720‐3104
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26
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Frazer DM, Wilkins SJ, Vulpe CD, Anderson GJ. The role of duodenal cytochrome b in intestinal iron absorption remains unclear. Blood 2006; 106:4413; author reply 4414. [PMID: 16326980 PMCID: PMC1895251 DOI: 10.1182/blood-2005-07-2923] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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27
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Armendáriz AD, Olivares F, Pulgar R, Loguinov A, Cambiazo V, Vulpe CD, González M. Gene expression profiling in wild-type and metallothionein mutant fibroblast cell lines. Biol Res 2006; 39:125-42. [PMID: 16629173 DOI: 10.4067/s0716-97602006000100015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The role of metallothioneins (MT) in copper homeostasis is of great interest, as it appears to be partially responsible for the regulation of intracellular copper levels during adaptation to extracellular excess of the metal. To further investigate a possible role of MTs in copper metabolism, a genomics approach was utilized to evaluate the role of MT on gene expression. Microarray analysis was used to examine the effects of copper overload in fibroblast cells from normal and MT I and II double knock-out mice (MT-/-). As a first step, we compared genes that were significantly upregulated in wild-type and MT-/- cells exposed to copper. Even though wild-type and mutant cells are undistinguishable in terms of their morphological features and rates of growth, our results show that MT-/- cells do not respond with induction of typical markers of cellular stress under copper excess conditions, as observed in the wild-type cell line, suggesting that the transcription initiation rate or the mRNA stability of stress genes is affected when there is an alteration in the copper store capacity. The functional classification of other up-regulated genes in both cell lines indicates that a large proportion (>80%) belong to two major categories: 1) metabolism; and 2) cellular physiological processes, suggesting that at the transcriptional level copper overload induces the expression of genes associated with diverse molecular functions. These results open the possibility to understand how copper homeostasis is being coordinated with other metabolic pathways.
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Affiliation(s)
- Angela D Armendáriz
- Department of Nutritional Science and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA
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28
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Shayeghi M, Latunde-Dada GO, Oakhill JS, Laftah AH, Takeuchi K, Halliday N, Khan Y, Warley A, McCann FE, Hider RC, Frazer DM, Anderson GJ, Vulpe CD, Simpson RJ, McKie AT. Identification of an Intestinal Heme Transporter. Cell 2005; 122:789-801. [PMID: 16143108 DOI: 10.1016/j.cell.2005.06.025] [Citation(s) in RCA: 467] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 05/20/2005] [Accepted: 06/17/2005] [Indexed: 12/14/2022]
Abstract
Dietary heme iron is an important nutritional source of iron in carnivores and omnivores that is more readily absorbed than non-heme iron derived from vegetables and grain. Most heme is absorbed in the proximal intestine, with absorptive capacity decreasing distally. We utilized a subtractive hybridization approach to isolate a heme transporter from duodenum by taking advantage of the intestinal gradient for heme absorption. Here we show a membrane protein named HCP 1 (heme carrier protein 1), with homology to bacterial metal-tetracycline transporters, mediates heme uptake by cells in a temperature-dependent and saturable manner. HCP 1 mRNA was highly expressed in duodenum and regulated by hypoxia. HCP 1 protein was iron regulated and localized to the brush-border membrane of duodenal enterocytes in iron deficiency. Our data indicate that HCP 1 is the long-sought intestinal heme transporter.
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Affiliation(s)
- Majid Shayeghi
- Department of Life Sciences, Nutritional Sciences Research Division, Franklin-Wilkins Building, Kings College London, 150 Stamford Street, London SE1 9NN, UK
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29
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Anderson GJ, Frazer DM, McKie AT, Vulpe CD, Smith A. Mechanisms of Haem and Non-Haem Iron Absorption: Lessons from Inherited Disorders of Iron Metabolism. Biometals 2005; 18:339-48. [PMID: 16158226 DOI: 10.1007/s10534-005-3708-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Our current state of knowledge of the mechanism and regulation of intestinal iron absorption has been critically dependent on the analysis of inherited disorders of iron homeostasis in both humans and other animal species. Mutations in DMT1 and Ireg1 have revealed that these molecules are major mediators of iron transport across the brush border and basolateral membranes of the enterocyte, respectively. Similarly, the iron oxidase hephaestin has been shown to play an important role in basolateral iron efflux. The analysis of a range of human iron loading disorders has provided very strong evidence that the products of the HFE, TfR2, hepcidin and hemojuvelin genes comprise integral components of the machinery that regulates iron absorption and iron traffic around the body. Engineered mouse strains have already proved very effective in helping to dissect pathways of iron homeostasis, and in the future they will continue to provide important insights into the absorption of both inorganic and haem iron by the gut.
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Affiliation(s)
- Gregory J Anderson
- Iron Metabolism Laboratory, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Brisbane, Australia.
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30
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McGregor JA, Shayeghi M, Vulpe CD, Anderson GJ, Pietrangelo A, Simpson RJ, McKie AT. Impaired Iron Transport Activity of Ferroportin 1 in Hereditary Iron Overload. J Membr Biol 2005; 206:3-7. [PMID: 16440176 DOI: 10.1007/s00232-005-0768-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Indexed: 12/14/2022]
Abstract
To investigate the functional significance of mutations in Ferroportin that cause hereditary iron overload, we directly measured the iron efflux activity of the proteins expressed in Xenopus oocytes. We found that wild type and mutant Ferroportin molecules (A77D, N144H, Q248H and V162Delta) were all expressed at the plasma membrane at similar levels. All mutations caused significant reductions in (59)Fe efflux compared to wild type but all retained some residual transport activity. A77D had the strongest effect on (59)Fe efflux (remaining activity 9% of wild-type control), whereas the N144H mutation retained the highest efflux activity (42% of control). The Q248H and V162Delta mutations were intermediate between these values. Co-injection of mutant and wild-type mRNAs revealed that the A77D and N144H mutations had a dominant negative effect on the function of the WT protein.
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Affiliation(s)
- J A McGregor
- Division of Nutritional Sciences, King's College London, London, UK
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31
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Abstract
The level at which copper becomes toxic is not clear. Several studies have indicated that copper causes oxidative stress; however, most have tested very high levels of copper exposure. We currently have only a limited understanding of the protective systems that operate in cells chronically exposed to copper. Additionally, the limits of homeostatic regulation are not known, making it difficult to define the milder effects of copper excess. Furthermore, a robust assay to facilitate the diagnosis of copper excess and to distinguish mild, moderate, and severe copper overload is needed. To address these issues, we have investigated the effects on steady-state gene expression of chronic copper overload in a cell culture model system using cDNA microarrays. For this study we utilized cells from genetic models of copper overload: fibroblast cells from two mouse mutants, C57BL/6- Atp7aMobrand C57BL/6- Atp7aModap. These cell lines accumulate copper to abnormally high levels in normal culture media due to a defect in copper export from the cell. We identified 12 differentially expressed genes in common using our outlier identification methods. Surprisingly, our results show no evidence of oxidative stress in the copper-loaded cells. In addition, candidate components perhaps responsible for a copper-specific homeostatic response are identified. The genes that encode for the prion protein and the amyloid-β precursor protein, two known copper-binding proteins, are upregulated in both cell lines.
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Affiliation(s)
- Angela D Armendariz
- Department of Nutritional Science and Toxicology, University of California, Berkeley 94720, USA
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32
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Latunde-Dada GO, Vulpe CD, Anderson GJ, Simpson RJ, McKie AT. Tissue-specific changes in iron metabolism genes in mice following phenylhydrazine-induced haemolysis. Biochim Biophys Acta Mol Basis Dis 2004; 1690:169-76. [PMID: 15469906 DOI: 10.1016/j.bbadis.2004.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 06/09/2004] [Accepted: 06/14/2004] [Indexed: 10/26/2022]
Abstract
Iron metabolism in animals is altered by haemolytic anaemia induced by phenylhydrazine (PHZ). In common with a number of other modulators of iron metabolism, the mode and the mechanisms of this response are yet to be determined. However, recent studies have shown increased expression of the ferrous transporter DMT1 in the duodenum and other tissues of mice administered PHZ. We examined the expression of the ferric reductase Dcytb, DMT1 and some other genes involved in Fe metabolism in tissues of mice dosed with PHZ. The expression of iron-related genes in the duodenum, liver, and spleen of the mice were evaluated using Northern blot analyses, RT-PCR and immunocytochemistry. Dcytb, and DMT1 mRNA and protein increased markedly in the duodenum of mice given PHZ. The efflux protein Ireg1 also increased in the duodenum of the treated mice. These changes correlated with a decrease in hepatic hepcidin expression. Dcytb, DMT1, Ireg1 and transferrin receptor 1 mRNA expression in the spleen and liver of mice treated with PHZ responded to the enhanced iron demand associated with the resulting stimulation of erythropoiesis. Enhanced iron absorption observed in PHZ-treated animals is facilitated by the up-regulation of the genes involved in iron transport and recycling. The probable association of the erythroid and the store regulators of iron homeostasis and absorption in the mice is discussed.
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Affiliation(s)
- G O Latunde-Dada
- Department of Life Sciences, King's College, Franklin-Wilkins Building, 150 Stamford Street, SE1 9NN, London, UK
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33
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Frazer DM, Inglis HR, Wilkins SJ, Millard KN, Steele TM, McLaren GD, McKie AT, Vulpe CD, Anderson GJ. Delayed hepcidin response explains the lag period in iron absorption following a stimulus to increase erythropoiesis. Gut 2004; 53:1509-15. [PMID: 15361505 PMCID: PMC1774251 DOI: 10.1136/gut.2003.037416] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 03/31/2004] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The delay of several days between an erythropoietic stimulus and the subsequent increase in intestinal iron absorption is commonly believed to represent the time required for body signals to programme the immature crypt enterocytes and for these cells to migrate to the villus. Recent data however suggest that signals from the body to alter absorption are mediated by circulating hepcidin and that this peptide exerts its effect on mature villus enterocytes. METHODS We have examined the delay in the absorptive response following stimulated erythropoiesis using phenylhydrazine induced haemolysis and correlated this with expression of hepcidin in the liver and iron transporters in the duodenum. RESULTS There was a delay of four days following haemolysis before a significant increase in iron absorption was observed. Hepatic hepcidin expression did not decrease until day 3, reaching almost undetectable levels by days 4 and 5. This coincided with the increase in duodenal expression of divalent metal transporter 1, duodenal cytochrome b, and Ireg1. CONCLUSION These results suggest that the delayed increase in iron absorption following stimulated erythropoiesis is attributable to a lag in the hepcidin response rather than crypt programming, and are consistent with a direct effect of the hepcidin pathway on mature villus enterocytes.
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Affiliation(s)
- D M Frazer
- Iron Metabolism Laboratory, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Brisbane, Queensland 4029, Australia
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34
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Frazer DM, Wilkins SJ, Millard KN, McKie AT, Vulpe CD, Anderson GJ. Increased hepcidin expression and hypoferraemia associated with an acute phase response are not affected by inactivation of HFE. Br J Haematol 2004; 126:434-6. [PMID: 15257718 DOI: 10.1111/j.1365-2141.2004.05044.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The effect of HFE inactivation on iron homeostasis during an acute phase response was investigated in mice. HFE knockout, beta2-microglobulin knockout and C57BL/6J mice were injected with Freund's Complete Adjuvant to induce an acute phase response and hepatic hepcidin expression and serum transferrin saturation was determined 16 h later. Hepcidin mRNA increased in all strains in response to an acute phase stimulus when compared with untreated control animals. Hypoferraemia also occurred in all strains, indicating that both the upregulation of hepcidin and the decrease in transferrin saturation associated with an acute phase response is not dependent on HFE function.
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Affiliation(s)
- David M Frazer
- Iron Metabolism Laboratory, The Queensland Institute of Medical Research and The University of Queensland, PO Royal Brisbane Hospital, Brisbane, Queensland, Australia
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35
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Kuo YM, Su T, Chen H, Attieh Z, Syed BA, McKie AT, Anderson GJ, Gitschier J, Vulpe CD. Mislocalisation of hephaestin, a multicopper ferroxidase involved in basolateral intestinal iron transport, in the sex linked anaemia mouse. Gut 2004; 53:201-6. [PMID: 14724150 PMCID: PMC1774920 DOI: 10.1136/gut.2003.019026] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Hephaestin is a multicopper ferroxidase required for basolateral transport of iron from enterocytes. Sex linked anaemia (sla) mice have a defect in the release of iron from intestinal enterocytes into the circulation due to an interstitial deletion in the hephaestin gene (heph). RESULTS We have demonstrated that hephaestin is primarily localised to a supranuclear compartment in both intestinal enterocytes and in cultured cells. In normal intestinal enterocytes, hephaestin was also present on the basolateral surface. In sla mice, hephaestin was present only in the supranuclear compartment. In contrast, the iron permease Ireg1 localised to the basolateral membrane in both control and sla mice. CONCLUSION We suggest that mislocalisation of hephaestin likely contributes to the functional defect in sla intestinal epithelium.
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Affiliation(s)
- Y M Kuo
- Departments of Medicine and Pediatrics, University of California-San Francisco, San Francisco, CA 94143-0794, USA
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36
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Frazer DM, Wilkins SJ, Becker EM, Murphy TL, Vulpe CD, McKie AT, Anderson GJ. A rapid decrease in the expression of DMT1 and Dcytb but not Ireg1 or hephaestin explains the mucosal block phenomenon of iron absorption. Gut 2003; 52:340-6. [PMID: 12584213 PMCID: PMC1773562 DOI: 10.1136/gut.52.3.340] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/11/2002] [Indexed: 12/18/2022]
Abstract
BACKGROUND A large oral dose of iron will reduce the absorption of a subsequent smaller dose of iron in a phenomenon known as mucosal block. Molecular analysis of this process may provide insights into the regulation of intestinal iron absorption. AIMS To determine the effect of an oral bolus of iron on duodenal expression of molecules associated with intestinal iron transport in rats and to relate this to changes in iron absorption. METHODS Rats were given an oral dose of iron and duodenal expression of divalent metal transporter 1 (DMT1), Dcytb, Ireg1, and hephaestin (Hp) was determined using the ribonuclease protection assay, western blotting, and immunofluorescence. Iron absorption was measured using radioactive (59)Fe. RESULTS A decrease in intestinal iron absorption occurred following an oral dose of iron and this was associated with increased enterocyte iron levels, as assessed by iron regulatory protein activity and immunoblotting for ferritin. Reduced absorption was also accompanied by a rapid decrease in expression of the mRNAs encoding the brush border iron transport molecules Dcytb and the iron responsive element (IRE) containing the splice variant of DMT1. No such change was seen in expression of the non-IRE splice variant of DMT1 or the basolateral iron transport molecules Ireg1 and Hp. Similar changes were observed at the protein level. CONCLUSIONS These data indicate that brush border, but not basolateral, iron transport components are regulated locally by enterocyte iron levels and support the hypothesis that systemic stimuli exert their primary effect on basolateral transport molecules.
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Affiliation(s)
- D M Frazer
- Joint Clinical Sciences Program, the Queensland Institute of Medical Research and the University of Queensland, PO Royal Brisbane Hospital, Brisbane, Queensland 4029, Australia
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37
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Anderson GJ, Frazer DM, McKie AT, Wilkins SJ, Vulpe CD. The expression and regulation of the iron transport molecules hephaestin and IREG1: implications for the control of iron export from the small intestine. Cell Biochem Biophys 2003; 36:137-46. [PMID: 12139399 DOI: 10.1385/cbb:36:2-3:137] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The amount of iron in the body is controlled at the point of absorption in the proximal small intestine. Dietary iron enters the intestinal epithelium via the brush-border transporter DMT1 and exits through the basolateral membranes. The basolateral transfer of iron requires two components: a copper-containing iron oxidase known as hephaestin and a membrane transport protein IREG1. The amount of iron traversing the enterocytes is directly related to body iron requirements and inversely related to the iron content of the intestinal epithelium. We propose that body signals control iron absorption by first acting on crypt enterocytes to determine the expression of basolateral transport components. This, in turn, modulates the intracellular iron content of mature epithelial cells, which ultimately determines the activity of the brush-border transporter DMT1.
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Affiliation(s)
- Gregory J Anderson
- Iron Metabolism Laboratory, The Queensland Institute of Medical Research, Australia.
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38
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Latunde-Dada GO, Van der Westhuizen J, Vulpe CD, Anderson GJ, Simpson RJ, McKie AT. Molecular and functional roles of duodenal cytochrome B (Dcytb) in iron metabolism. Blood Cells Mol Dis 2002; 29:356-60. [PMID: 12547225 DOI: 10.1006/bcmd.2002.0574] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Dcytb has been identified as the mammalian transplasma ferric reductase that catalyzes the reduction of ferric to ferrous iron in the process of iron absorption. Its mRNA and protein levels are up-regulated by several independent stimulators of iron absorption. Furthermore, its cDNA encodes putative binding sites for heme and ascorbic acid. Using Northern and Western blots, RT-PCR and confocal microscopy, we studied the expression and localisation of Dcytb in cell lines and tissues of CD1 mice. Dcytb expression and function were modulated by iron. Dcytb and DMT1, both predominantly localised in the apical region of the duodenum were up-regulated in iron deficiency. Dcytb, the iron regulated ferric reductase may also utilize cytoplasmic ascorbate as electron donor for transmembrane reduction of iron. Dcytb expression was found in other tissues apart from the duodenum and its regulation and functions at these other sites are of interest in iron metabolism.
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Affiliation(s)
- G O Latunde-Dada
- Division of Life Sciences, King's College, 150 Stamford Street, London SE1 9NN, UK
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39
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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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40
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Frazer DM, Wilkins SJ, Becker EM, Vulpe CD, McKie AT, Trinder D, Anderson GJ. Hepcidin expression inversely correlates with the expression of duodenal iron transporters and iron absorption in rats. Gastroenterology 2002; 123:835-44. [PMID: 12198710 DOI: 10.1053/gast.2002.35353] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Hepcidin is an antimicrobial peptide thought to be involved in the regulation of intestinal iron absorption. To further investigate its role in this process, we examined hepatic and duodenal gene expression in rats after the switch from a control diet to an iron-deficient diet. METHODS Adult rats on an iron-replete diet were switched to an iron-deficient diet and the expression of iron homeostasis molecules in duodenal and liver tissue was studied over 14 days. Intestinal iron absorption was determined at these same time-points by measuring the retention of an oral dose of (59)Fe. RESULTS Iron absorption increased 2.7-fold within 6 days of switching to an iron-deficient diet and was accompanied by an increase in the duodenal expression of Dcytb, divalent metal transporter 1, and Ireg1. These changes precisely correlated with decreases in hepatic hepcidin expression and transferrin saturation. No change in iron stores or hematologic parameters was detected. CONCLUSIONS This study showed a close relationship between the expression of hepcidin, duodenal iron transporters, and iron absorption. Both hepcidin expression and iron absorption can be regulated before iron stores and erythropoiesis are affected, and transferrin saturation may signal such changes.
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Affiliation(s)
- David M Frazer
- Joint Clinical Sciences Program, The Queensland Institute of Medical Research and The University of Queensland, Royal Brisbane Hospital, Brisbane, Queensland, Australia
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41
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McKie AT, Latunde-Dada GO, Miret S, McGregor JA, Anderson GJ, Vulpe CD, Wrigglesworth JM, Simpson RJ. Molecular evidence for the role of a ferric reductase in iron transport. Biochem Soc Trans 2002; 30:722-4. [PMID: 12196176 DOI: 10.1042/bst0300722] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Duodenal cytochrome b (Dcytb) is a haem protein similar to the cytochrome b561 protein family. Dcytb is highly expressed in duodenal brush-border membrane and is implicated in dietary iron absorption by reducing dietary ferric iron to the ferrous form for transport via Nramp2/DCT1 (divalent-cation transporter 1)/DMT1 (divalent metal-transporter 1). The protein is expressed in other tissues and may account for ferric reductase activity at other sites in the body.
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Affiliation(s)
- A T McKie
- Division of Life Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NN, UK.
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42
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Anderson GJ, Frazer DM, Wilkins SJ, Becker EM, Millard KN, Murphy TL, McKie AT, Vulpe CD. Relationship between intestinal iron-transporter expression, hepatic hepcidin levels and the control of iron absorption. Biochem Soc Trans 2002; 30:724-6. [PMID: 12196177 DOI: 10.1042/bst0300724] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hepcidin is an anti-microbial peptide predicted to be involved in the regulation of intestinal iron absorption. We have examined the relationship between the expression of hepcidin in the liver and the expression of the iron-transport molecules divalent-metal transporter 1, duodenal cytochrome b, hephaestin and Ireg1 in the duodenum of rats switched from an iron-replete to an iron-deficient diet or treated to induce an acute phase response. In each case, elevated hepcidin expression correlated with reduced iron absorption and depressed levels of iron-transport molecules. These data are consistent with hepcidin playing a role as a negative regulator of intestinal iron absorption.
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Affiliation(s)
- G J Anderson
- Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Herston, Queensland 4029, Australia.
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43
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Frazer DM, Vulpe CD, McKie AT, Wilkins SJ, Trinder D, Cleghorn GJ, Anderson GJ. Cloning and gastrointestinal expression of rat hephaestin: relationship to other iron transport proteins. Am J Physiol Gastrointest Liver Physiol 2001; 281:G931-9. [PMID: 11557513 DOI: 10.1152/ajpgi.2001.281.4.g931] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The membrane-bound ceruloplasmin homolog hephaestin plays a critical role in intestinal iron absorption. The aims of this study were to clone the rat hephaestin gene and to examine its expression in the gastrointestinal tract in relation to other genes encoding iron transport proteins. The rat hephaestin gene was isolated from intestinal mRNA and was found to encode a protein 96% identical to mouse hephaestin. Analysis by ribonuclease protection assay and Western blotting showed that hephaestin was expressed at high levels throughout the small intestine and colon. Immunofluorescence localized the hephaestin protein to the mature villus enterocytes with little or no expression in the crypts. Variations in iron status had a small but nonsignificant effect on hephaestin expression in the duodenum. The high sequence conservation between rat and mouse hephaestin is consistent with this protein playing a central role in intestinal iron absorption, although its precise function remains to be determined.
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Affiliation(s)
- D M Frazer
- Joint Clinical Sciences Program, The Queensland Institute of Medical Research and The University of Queensland, PO Royal Brisbane Hospital, Brisbane, Queensland 4029, Australia
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Vulpe CD, Kuo YM, Murphy TL, Cowley L, Askwith C, Libina N, Gitschier J, Anderson GJ. Hephaestin, a ceruloplasmin homologue implicated in intestinal iron transport, is defective in the sla mouse. Nat Genet 1999; 21:195-9. [PMID: 9988272 DOI: 10.1038/5979] [Citation(s) in RCA: 725] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Iron is essential for many cellular functions; consequently, disturbances of iron homeostasis, leading to either iron deficiency or iron overload, can have significant clinical consequences. Despite the clinical prevalence of these disorders, the mechanism by which dietary iron is absorbed into the body is poorly understood. We have identified a key component in intestinal iron transport by study of the sex-linked anaemia (sla) mouse, which has a block in intestinal iron transport. Mice carrying the sla mutation develop moderate to severe microcytic hypochromic anaemia. Although these mice take up iron from the intestinal lumen into mature epithelial cells normally, the subsequent exit of iron into the circulation is diminished. As a result, iron accumulates in enterocytes and is lost during turnover of the intestinal epithelium. Biochemical studies have failed to identify the underlying difference between sla and normal mice, therefore, we used a genetic approach to identify the gene mutant in sla mice. We describe here a novel gene, Heph, encoding a transmembrane-bound ceruloplasmin homologue that is mutant in the sla mouse and highly expressed in intestine. We suggest that the hephaestin protein is a multicopper ferroxidase necessary for iron egress from intestinal enterocytes into the circulation and that it is an important link between copper and iron metabolism in mammals.
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Affiliation(s)
- C D Vulpe
- Howard Hughes Medical Institute and the Department of Medicine, University of California at San Francisco, 94143, USA
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45
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Abstract
Cellular copper transport processes are required by all organisms for correct utilization in cell biochemical processes and avoidance of the toxicity of copper excess. Copper import into bacterial, yeast, and mammalian cells requires the coordinate function of proteins with both metal-binding and catalytic domains in mediated transport steps. Following entry, detoxification mechanisms found across species include the binding of copper to specific proteins (e.g. metallothioneins) and the transfer of copper into isolated cell compartments (e.g. periplasmic space, lysosome). Multiple proteins mediate intracellular transfers in bacteria, and glutathione may play a major role in cytosolic copper delivery to cuproenzymes in mammalian cells. Study of two human disorders of copper transport, Menkes disease and Wilson disease, led to the identification of an important category of proteins mediating cell copper export. The Menkes and Wilson disease gene products are copper-transporting ATPases of the P type, with ATPase domains and N-terminal metal-binding amino acid motifs that are evolutionarily conserved in unicellular and mammalian organisms. These observations suggest that yeast and bacterial copper transport proteins, or individual domains of these proteins, may generally have homologues in mammalian systems.
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Affiliation(s)
- C D Vulpe
- Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0748, USA
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46
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Abstract
We have examined T-cell receptor alpha- and beta-chain variable (V) region gene usage in T-cell populations predicted to have different major histocompatibility complex-restriction specificities. Using a sensitive ribonuclease protection assay to measure T-cell receptor mRNA levels, we found no striking differences in the usage of three V alpha genes and three V beta genes in T-cell populations from three congeneic H-2-disparate strains of mice and between the mutually exclusive Ly2+ L3T4- and Ly2- L3T4+ T-cell subpopulations. These results suggest that major histocompatibility complex restriction cannot be explained by the differential usage of nonoverlapping V alpha or V beta gene pools. In contrast, striking but unpredictable differences were seen in V gene usage in populations of T cells selected by activation with particular alloantigens.
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MESH Headings
- Animals
- Antigens, Differentiation, T-Lymphocyte
- Antigens, Ly/analysis
- Antigens, Surface/analysis
- Cells, Cultured
- Cloning, Molecular
- Gene Expression Regulation
- Genes
- Lymphocyte Activation
- Major Histocompatibility Complex
- Mice
- Mice, Inbred Strains
- RNA, Messenger/genetics
- Receptors, Antigen, T-Cell/genetics
- T-Lymphocytes/classification
- T-Lymphocytes/physiology
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