1
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Patwa J, Flora SJS. Copper: From enigma to therapeutic target for neurological disorder. Basic Clin Pharmacol Toxicol 2024; 134:778-791. [PMID: 38622813 DOI: 10.1111/bcpt.14010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 03/19/2024] [Accepted: 03/24/2024] [Indexed: 04/17/2024]
Abstract
Neurological disorders (NDs) have a negative impact on the lives of individuals. There could be two explanations for this: unclear aetiology and lack of effective therapy. However, research in the past few years has revealed the role of bio-metals dyshomeostasis in NDs. The imbalance in copper (Cu) concentration may be one of the main causative factors in NDs. In this review, we have discussed the role of Cu in NDs, especially Alzheimer's disease (AD), including the molecular mechanisms involved in Cu-associated NDs like oxidative stress, neuroinflammation, and protein misfolding. We have also summarized the recent Cu-targeting approaches and highlighted the in vitro and in vivo studies recently being reported on the subject. Based on the earlier published reports, it could be speculated that the Cu targeting strategy might be an interesting and potential therapeutic approach for NDs. Various difficulties must be overcome to develop safe and efficient Cu-targeting medications for NDs.
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Affiliation(s)
- Jayant Patwa
- Department of Pharmaceutical Sciences, Hemvati Nandan Bahuguna Garhwal University (A Central University), Srinagar Garhwal, Uttarakhand, India
| | - Swaran Jeet Singh Flora
- Era College of Pharmaceuticals, Era Lucknow Medical University, Lucknow, Uttar Pradesh, India
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2
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Dev S, Muchenditsi A, Gottlieb A, Deme P, Murphy S, Gabrielson KL, Dong Y, Hughes R, Haughey NJ, Hamilton JP, Lutsenko S. Oxysterol misbalance critically contributes to Wilson disease pathogenesis. SCIENCE ADVANCES 2022; 8:eadc9022. [PMID: 36260680 PMCID: PMC9581482 DOI: 10.1126/sciadv.adc9022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Wilson disease (WD) is a metabolic disorder caused by inactivation of the copper-transporting ATPase 2 (ATP7B) and copper (Cu) overload in tissues. Excess Cu causes oxidative stress and pathologic changes with poorly understood mechanistic connections. In Atp7b-/- mice with established liver disease, Cu overload activates the stress-sensitive transcription factor Nrf2 (nuclear factor erythroid-derived 2-like 2). Nrf2 targets, especially sulfotransferase 1e1 (Sult1e1), are strongly induced and cause elevation of sulfated sterols, whereas oxysterols are decreased. This sterol misbalance results in inhibition of the liver X receptor (LXR) and up-regulation of LXR targets associated with inflammatory responses. Pharmacological inhibition of Sult1e1 partially reverses oxysterol misbalance and LXR inhibition. Contribution of this pathway to advanced hepatic WD was demonstrated by treating mice with an LXR agonist. Treatment decreased inflammation by reducing expression of proinflammatory molecules, diminished fibrosis by down-regulating the noncanonical transforming growth factor-β signaling pathway, and improved liver morphology and function. Thus, the identified pathway is an important driver of WD.
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Affiliation(s)
- Som Dev
- Department of Physiology, Johns Hopkins University, School of Medicine, 725 North Wolfe St, Baltimore, MD 21205, USA
| | - Abigael Muchenditsi
- Department of Physiology, Johns Hopkins University, School of Medicine, 725 North Wolfe St, Baltimore, MD 21205, USA
| | - Aline Gottlieb
- Department of Physiology, Johns Hopkins University, School of Medicine, 725 North Wolfe St, Baltimore, MD 21205, USA
| | - Pragney Deme
- Department of Neurology, Johns Hopkins University, School of Medicine, 600 North Wolfe St, Baltimore, MD 21287, USA
| | - Sean Murphy
- Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Kathleen L. Gabrielson
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University, School of Medicine, 733 North Broadway, Baltimore, MD 21205, USA
| | - Yixuan Dong
- Department of Physiology, Johns Hopkins University, School of Medicine, 725 North Wolfe St, Baltimore, MD 21205, USA
| | - Robert Hughes
- Department of Medicine, Johns Hopkins University, School of Medicine, 733 North Broadway, Baltimore, MD 21205, USA
| | - Norman J. Haughey
- Department of Neurology, Johns Hopkins University, School of Medicine, 600 North Wolfe St, Baltimore, MD 21287, USA
| | - James P. Hamilton
- Department of Medicine, Johns Hopkins University, School of Medicine, 733 North Broadway, Baltimore, MD 21205, USA
- Corresponding author. (S.L.); (J.P.H.)
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins University, School of Medicine, 725 North Wolfe St, Baltimore, MD 21205, USA
- Department of Medicine, Johns Hopkins University, School of Medicine, 733 North Broadway, Baltimore, MD 21205, USA
- Corresponding author. (S.L.); (J.P.H.)
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3
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Single-cell visualization and quantification of trace metals in Chlamydomonas lysosome-related organelles. Proc Natl Acad Sci U S A 2021; 118:2026811118. [PMID: 33879572 DOI: 10.1073/pnas.2026811118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The acidocalcisome is an acidic organelle in the cytosol of eukaryotes, defined by its low pH and high calcium and polyphosphate content. It is visualized as an electron-dense object by transmission electron microscopy (TEM) or described with mass spectrometry (MS)-based imaging techniques or multimodal X-ray fluorescence microscopy (XFM) based on its unique elemental composition. Compared with MS-based imaging techniques, XFM offers the additional advantage of absolute quantification of trace metal content, since sectioning of the cell is not required and metabolic states can be preserved rapidly by either vitrification or chemical fixation. We employed XFM in Chlamydomonas reinhardtii to determine single-cell and organelle trace metal quotas within algal cells in situations of trace metal overaccumulation (Fe and Cu). We found up to 70% of the cellular Cu and 80% of Fe sequestered in acidocalcisomes in these conditions and identified two distinct populations of acidocalcisomes, defined by their unique trace elemental makeup. We utilized the vtc1 mutant, defective in polyphosphate synthesis and failing to accumulate Ca, to show that Fe sequestration is not dependent on either. Finally, quantitation of the Fe and Cu contents of individual cells and compartments via XFM, over a range of cellular metal quotas created by nutritional and genetic perturbations, indicated excellent correlation with bulk data from corresponding cell cultures, establishing a framework to distinguish the nutritional status of single cells.
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4
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Kim JH, Matsubara T, Lee J, Fenollar-Ferrer C, Han K, Kim D, Jia S, Chang CJ, Yang H, Nagano T, Krausz KW, Yim SH, Gonzalez FJ. Lysosomal SLC46A3 modulates hepatic cytosolic copper homeostasis. Nat Commun 2021; 12:290. [PMID: 33436590 PMCID: PMC7804329 DOI: 10.1038/s41467-020-20461-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 12/02/2020] [Indexed: 01/05/2023] Open
Abstract
The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes hepatic toxicity associated with prominent lipid accumulation in humans. Here, the authors report that the lysosomal copper transporter SLC46A3 is induced by TCDD and underlies the hepatic lipid accumulation in mice, potentially via effects on mitochondrial function. SLC46A3 was localized to the lysosome where it modulated intracellular copper levels. Forced expression of hepatic SLC46A3 resulted in decreased mitochondrial membrane potential and abnormal mitochondria morphology consistent with lower copper levels. SLC46A3 expression increased hepatic lipid accumulation similar to the known effects of TCDD exposure in mice and humans. The TCDD-induced hepatic triglyceride accumulation was significantly decreased in Slc46a3-/- mice and was more pronounced when these mice were fed a high-fat diet, as compared to wild-type mice. These data are consistent with a model where lysosomal SLC46A3 induction by TCDD leads to cytosolic copper deficiency resulting in mitochondrial dysfunction leading to lower lipid catabolism, thus linking copper status to mitochondrial function, lipid metabolism and TCDD-induced liver toxicity.
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Affiliation(s)
- Jung-Hwan Kim
- Department of Pharmacology, School of Medicine, Institute of Health Sciences, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Tsutomu Matsubara
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Anatomy and Regenerative Biology, Osaka City University Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Jaekwon Lee
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Cristina Fenollar-Ferrer
- Laboratory of Molecular & Cellular Neurobiology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kyungreem Han
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Donghwan Kim
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Shang Jia
- Departments of Chemistry and Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Christopher J Chang
- Departments of Chemistry and Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Heejung Yang
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- College of Pharmacy, Kangwon National University, Chuncheon, Republic of Korea
| | - Tomokazu Nagano
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- Sumitomo Dainippon Pharma Co. Ltd., Osaka, Japan
| | - Kristopher W Krausz
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sun-Hee Yim
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Environmental Toxicology, Texas Tech University, Lubbock, TX, 41163, USA
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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5
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Wallnöfer EA, Thurner GC, Kremser C, Talasz H, Stollenwerk MM, Helbok A, Klammsteiner N, Albrecht-Schgoer K, Dietrich H, Jaschke W, Debbage P. Albumin-based nanoparticles as contrast medium for MRI: vascular imaging, tissue and cell interactions, and pharmacokinetics of second-generation nanoparticles. Histochem Cell Biol 2020; 155:19-73. [PMID: 33040183 DOI: 10.1007/s00418-020-01919-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2020] [Indexed: 12/14/2022]
Abstract
This multidisciplinary study examined the pharmacokinetics of nanoparticles based on albumin-DTPA-gadolinium chelates, testing the hypothesis that these nanoparticles create a stronger vessel signal than conventional gadolinium-based contrast agents and exploring if they are safe for clinical use. Nanoparticles based on human serum albumin, bearing gadolinium and designed for use in magnetic resonance imaging, were used to generate magnet resonance images (MRI) of the vascular system in rats ("blood pool imaging"). At the low nanoparticle doses used for radionuclide imaging, nanoparticle-associated metals were cleared from the blood into the liver during the first 4 h after nanoparticle application. At the higher doses required for MRI, the liver became saturated and kidney and spleen acted as additional sinks for the metals, and accounted for most processing of the nanoparticles. The multiple components of the nanoparticles were cleared independently of one another. Albumin was detected in liver, spleen, and kidneys for up to 2 days after intravenous injection. Gadolinium was retained in the liver, kidneys, and spleen in significant concentrations for much longer. Gadolinium was present as significant fractions of initial dose for longer than 2 weeks after application, and gadolinium clearance was only complete after 6 weeks. Our analysis could not account quantitatively for the full dose of gadolinium that was applied, but numerous organs were found to contain gadolinium in the collagen of their connective tissues. Multiple lines of evidence indicated intracellular processing opening the DTPA chelates and leading to gadolinium long-term storage, in particular inside lysosomes. Turnover of the stored gadolinium was found to occur in soluble form in the kidneys, the liver, and the colon for up to 3 weeks after application. Gadolinium overload poses a significant hazard due to the high toxicity of free gadolinium ions. We discuss the relevance of our findings to gadolinium-deposition diseases.
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Affiliation(s)
- E A Wallnöfer
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - G C Thurner
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria
| | - C Kremser
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - H Talasz
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020, Innsbruck, Austria
| | - M M Stollenwerk
- Faculty of Health and Society, Biomedical Laboratory Science, University Hospital MAS, Malmö University, 205 06, Malmö, Sweden
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria
| | - A Helbok
- Department of Nuclear Medicine, Innsbruck Medical University, Anichstrasse 35, 6020, Innsbruck, Austria
| | - N Klammsteiner
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria
| | - K Albrecht-Schgoer
- Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University Innsbruck, Innrain 80-82/IV, 6020, Innsbruck, Austria
- Institute of Cell Genetics, Department for Pharmacology and Genetics, Medical University of Innsbruck, Peter-Mayr-Strasse 1a, 6020, Innsbruck, Austria
| | - H Dietrich
- Central Laboratory Animal Facilities, Innsbruck Medical University, Peter-Mayr-Strasse 4a, 6020, Innsbruck, Austria
| | - W Jaschke
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - P Debbage
- Division of Histology and Embryology, Department of Anatomy, Histology and Embryology, Medical University of Innsbruck, Müllerstrasse 59, 6020, Innsbruck, Austria.
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6
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Polishchuk RS, Polishchuk EV. From and to the Golgi - defining the Wilson disease protein road map. FEBS Lett 2019; 593:2341-2350. [PMID: 31408533 DOI: 10.1002/1873-3468.13575] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/01/2019] [Accepted: 08/08/2019] [Indexed: 11/05/2022]
Abstract
Recent studies highlight the continued growth in the identification of a variety of cellular functions that involve the Golgi apparatus. Apart from well-known membrane sorting/trafficking and glycosylation machineries, the Golgi harbors molecular platforms operating in intracellular signaling, cytoskeleton organization, and protein quality control mechanisms. One of new emerging Golgi functions consists in the regulation of copper homeostasis by coordinating the relocation and activity of copper transporters. Of these, the Cu-transporting ATPase ATP7B (known as Wilson disease protein) plays a key role in the maintenance of the Cu balance in the body via the supply of essential Cu to the systemic circulation and via elimination of excess Cu into the bile. These activities require tightly regulated shuttling of ATP7B between the Golgi and different post-Golgi compartments. Despite significant progress over recent years, a number of issues regarding ATP7B trafficking remain to be clarified. This review summarizes current views on ATP7B trafficking pathways from and to the Golgi and underscores the challenges that should be addressed to define the ATP7B trafficking routes and mechanisms in health and disease.
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Affiliation(s)
- Roman S Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy
| | - Elena V Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy.,ITMO University, St. Petersburg, Russia
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7
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Cocucci E, Kim JY, Bai Y, Pabla N. Role of Passive Diffusion, Transporters, and Membrane Trafficking-Mediated Processes in Cellular Drug Transport. Clin Pharmacol Ther 2016; 101:121-129. [PMID: 27804130 DOI: 10.1002/cpt.545] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 12/11/2022]
Abstract
Intracellular drug accumulation is thought to be dictated by two major processes, passive diffusion through the lipid membrane or membrane transporters. The relative role played by these distinct processes remains actively debated. Moreover, the role of membrane-trafficking in drug transport remains underappreciated and unexplored. Here we discuss the distinct processes involved in cellular drug distribution and propose that better experimental models are required to elucidate the differential contributions of various processes in intracellular drug accumulation.
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Affiliation(s)
- E Cocucci
- Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - J Y Kim
- Division of Pharmaceutics, School of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - Y Bai
- Division of Pharmaceutics, School of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
| | - N Pabla
- Division of Pharmaceutics, School of Pharmacy and Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, USA
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8
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Besnard A, Gautherot J, Julien B, Tebbi A, Garcin I, Doignon I, Péan N, Gonzales E, Cassio D, Grosse B, Liu B, Safya H, Cauchois F, Humbert L, Rainteau D, Tordjmann T. The P2X4 purinergic receptor impacts liver regeneration after partial hepatectomy in mice through the regulation of biliary homeostasis. Hepatology 2016; 64:941-53. [PMID: 27301647 DOI: 10.1002/hep.28675] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 05/25/2016] [Indexed: 02/06/2023]
Abstract
UNLABELLED Many regulatory pathways are involved in liver regeneration after partial hepatectomy (PH), to initiate growth, protect liver cells, and sustain remnant liver functions. Extracellular adenosine triphosphate rises in blood and bile after PH and contributes to liver regeneration, although purinergic receptors and mechanisms remain to be precisely explored. In this work we analyzed during regeneration after PH the involvement of P2X4 purinergic receptors, highly expressed in the liver. P2X4 receptor expression in the liver, liver histology, hepatocyte proliferation, plasma bile acid concentration, bile flow and composition, and lysosome distribution in hepatocytes were studied in wild-type and P2X4 knockout (KO) mice, before and after PH. P2X4 receptors were expressed in hepatocytes and Kupffer cells; in hepatocytes, P2X4 was concentrated in subcanalicular areas closely costained with lysosomal markers. After PH, delayed regeneration, hepatocyte necrosis, and cholestasis were observed in P2X4-KO mice. In P2X4-KO mice, post-PH biliary adaptation was impaired with a smaller increase in bile flow and HCO3 (-) biliary output, as well as altered biliary composition with reduced adenosine triphosphate and lysosomal enzyme release. In line with these data, lysosome distribution and biogenesis were altered in P2X4-KO compared with wild-type mice. CONCLUSION During liver regeneration after PH, P2X4 contributes to the complex control of biliary homeostasis through mechanisms involving pericanalicular lysosomes, with a resulting impact on hepatocyte protection and proliferation. (Hepatology 2016;64:941-953).
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Affiliation(s)
- Aurore Besnard
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France.,UPMC, Université Paris 06, Paris, France
| | - Julien Gautherot
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Boris Julien
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Ali Tebbi
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Isabelle Garcin
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Isabelle Doignon
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Noémie Péan
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Emmanuel Gonzales
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France.,Hépatologie pédiatrique, Hôpital du Kremlin Bicêtre, Le Kremlin Bicêtre, France
| | - Doris Cassio
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Brigitte Grosse
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Bingkaï Liu
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Hanaa Safya
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Florent Cauchois
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
| | - Lydie Humbert
- UPMC, Université Paris 06, Paris, France.,ERL INSERM U 1057, Faculté de Médecine Pierre et Marie Curie, Paris, France
| | - Dominique Rainteau
- UPMC, Université Paris 06, Paris, France.,ERL INSERM U 1057, Faculté de Médecine Pierre et Marie Curie, Paris, France
| | - Thierry Tordjmann
- INSERM U1174, Université Paris Sud, Orsay, France.,Université Paris Sud, Orsay, France
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9
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Xu W, Zeng Z, Jiang JH, Chang YT, Yuan L. Wahrnehmung der chemischen Prozesse in einzelnen Organellen mit niedermolekularen Fluoreszenzsonden. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510721] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Wang Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapur
- Laboratory of Bioimaging Probe Development, A*STAR; Singapur
- Department of Chemistry; Stanford University; USA
| | - Zebing Zeng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
| | - Jian-Hui Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
| | - Young-Tae Chang
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapur
- Laboratory of Bioimaging Probe Development, A*STAR; Singapur
| | - Lin Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 Volksrepublik China
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10
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Xu W, Zeng Z, Jiang JH, Chang YT, Yuan L. Discerning the Chemistry in Individual Organelles with Small-Molecule Fluorescent Probes. Angew Chem Int Ed Engl 2016; 55:13658-13699. [DOI: 10.1002/anie.201510721] [Citation(s) in RCA: 526] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Wang Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapore
- Laboratory of Bioimaging Probe Development, A*STAR; Singapore
- Department of Chemistry; Stanford University; USA
| | - Zebing Zeng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Jian-Hui Jiang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Young-Tae Chang
- Department of Chemistry and Medicinal Chemistry Programme; National University of Singapore; Singapore 117543 Singapore
- Laboratory of Bioimaging Probe Development, A*STAR; Singapore
| | - Lin Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
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11
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Polishchuk EV, Polishchuk RS. The emerging role of lysosomes in copper homeostasis. Metallomics 2016; 8:853-62. [PMID: 27339113 DOI: 10.1039/c6mt00058d] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The lysosomal system operates as a focal point where a number of important physiological processes such as endocytosis, autophagy and nutrient sensing converge. One of the key functions of lysosomes consists of regulating the metabolism/homeostasis of metals. Metal-containing components are carried to the lysosome through incoming membrane flows, while numerous transporters allow metal ions to move across the lysosome membrane. These properties enable lysosomes to direct metal fluxes to the sites where metal ions are either used by cellular components or sequestered. Copper belongs to a group of metals that are essential for the activity of vitally important enzymes, although it is toxic when in excess. Thus, copper uptake, supply and intracellular compartmentalization have to be tightly regulated. An increasing number of publications have indicated that these processes involve lysosomes. Here we review studies that reveal the expanding role of the lysosomal system as a hub for the control of Cu homeostasis and for the regulation of key Cu-dependent processes in health and disease.
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Affiliation(s)
- Elena V Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli (NA), 80078, Italy.
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12
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Hamilton JP, Koganti L, Muchenditsi A, Pendyala VS, Huso D, Hankin J, Murphy RC, Huster D, Merle U, Mangels C, Yang N, Potter JJ, Mezey E, Lutsenko S. Activation of liver X receptor/retinoid X receptor pathway ameliorates liver disease in Atp7B(-/-) (Wilson disease) mice. Hepatology 2016; 63:1828-41. [PMID: 26679751 PMCID: PMC4874878 DOI: 10.1002/hep.28406] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/30/2015] [Accepted: 12/15/2015] [Indexed: 01/07/2023]
Abstract
UNLABELLED Wilson disease (WD) is a hepatoneurological disorder caused by mutations in the copper-transporter, ATP7B. Copper accumulation in the liver is a hallmark of WD. Current therapy is based on copper chelation, which decreases the manifestations of liver disease, but often worsens neurological symptoms. We demonstrate that in Atp7b(-/-) mice, an animal model of WD, liver function can be significantly improved without copper chelation. Analysis of transcriptional and metabolic changes in samples from WD patients and Atp7b(-/-) mice identified dysregulation of nuclear receptors (NRs), especially the liver X receptor (LXR)/retinoid X receptor heterodimer, as an important event in WD pathogenesis. Treating Atp7b(-/-) mice with the LXR agonist, T0901317, ameliorated disease manifestations despite significant copper overload. Genetic markers of liver fibrosis and inflammatory cytokines were significantly decreased, lipid profiles normalized, and liver function and histology were improved. CONCLUSIONS The results demonstrate the major role of an altered NR function in the pathogenesis of WD and suggest that modulation of NR activity should be explored as a supplementary approach to improving liver function in WD. (Hepatology 2016;63:1828-1841).
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Affiliation(s)
- JP Hamilton
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - L Koganti
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - A Muchenditsi
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - VS Pendyala
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - D Huso
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - J Hankin
- University of Colorado, Denver, CO
| | | | - D Huster
- Deakoness Hospital, Leipzig, Germany
| | - U Merle
- University of Heidelberg, Germany
| | - C Mangels
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - N Yang
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - JJ Potter
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - E Mezey
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S. Lutsenko
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
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13
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Wu XZ, Zhang TT, Guo JG, Liu Z, Yang FH, Gao XH. Copper bioavailability, blood parameters, and nutrient balance in mink. J Anim Sci 2015; 93:176-84. [PMID: 25568366 DOI: 10.2527/jas.2014-8026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
A 3 × 3 + 1 factorial experiment was conducted based on a completely randomized design to evaluate the effects of different sources of copper on plasma metabolites, nutrient digestibility, relative copper bioavailability, and retention of some minerals in male mink. Animals in the control group were fed a basal diet, which mainly consisted of corn, fish meal, meat and bone meal, and soybean oil, with no copper supplementation. Mink in the other 9 treatments were fed the basal diet supplemented with Cu from reagent-grade copper sulfate (CuSO4), tribasic copper chloride (TBCC), or copper methionine (CuMet). Copper concentrations of the experimental diets were 50, 100, and 150 mg Cu/kg DM. Blood samples were collected via the toe clip at the end of study (d 42) to determine blood hematology and blood metabolites. A metabolism trial of 4 d was conducted during the last week of experimental feeding. There was a linear (P < 0.01) effect of dose of Cu on plasma Cu concentrations, ceruloplasmin concentration, and Cu-Zn superoxide dismutase activity. A linear response to Cu dose was noted for fat (P < 0.05) digestibility. Supplemental dose of Cu linearly increased (P < 0.05) liver Cu and decreased (P < 0.05) liver Zn level but did not alter liver Fe. The concentration of liver Cu of the mink fed with TBCC and CuMet diets was greater (P < 0.05) than that fed CuSO4. Compared with CuSO4 (100%), relative bioavailability values of TBCC were 104 and 104%, based on serum ceruloplasmin and liver copper, respectively, and relative bioavailability values of CuMet were 130 and 111%. CuMet and TBCC are more bioavailable than CuSO4. In conclusion, the relative bioavailability of CuMet obtained in this study was greater than that of CuSO4 and TBCC. Dose of Cu had an important effect on the regulating ceruloplasmin concentration, Cu-Zn superoxide dismutase activity, and the digestion of dietary fat in mink.
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Affiliation(s)
- X Z Wu
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun City, Jilin 130112, China
| | - T T Zhang
- Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun City, Jilin 130112, China
| | - J G Guo
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Z Liu
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - F H Yang
- Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun City, Jilin 130112, China State Key Lab for Molecular Biology of Special Economic Animals, Changchun City, Jilin 130112, China
| | - X H Gao
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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14
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Antony Jesu Prabhu P, Kaushik SJ, Mariojouls C, Surget A, Fontagné-Dicharry S, Schrama JW, Geurden I. Comparison of endogenous loss and maintenance need for minerals in rainbow trout (Oncorhynchus mykiss) fed fishmeal or plant ingredient-based diets. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:243-253. [PMID: 25500770 DOI: 10.1007/s10695-014-0020-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/05/2014] [Indexed: 06/04/2023]
Abstract
Mineral needs as affected by changes in dietary protein and oil sources were studied in rainbow trout. Duplicate groups (n = 30 fish per replicate) of rainbow trout (initial BW: 37 g) were fed either a fish meal/fish oil-based (M) or a complete plant ingredient (V)-based diet at four graded ration (R) levels [apparent satiation (AS), R75, R50 and R25 % of AS]; one treatment group was maintained under starvation. The feeding trial lasted 12 weeks at a water temperature of 17 °C. Dietary intake, apparent digestibility and initial and final whole-body composition data were used to calculate mineral gain which was regressed against digestible mineral intake (both expressed as mg or µg kg(-0.8) day(-1)). Starvation loss (SL), endogenous loss of fed fish (ELF, y-intercept at x = 0) and point of intake for zero balance (PZB, x-intercept at y = 0) were used as estimates of maintenance requirements. SL provided the lowest estimate, ELF provided the net requirement of a mineral for maintenance and PZB provided the digestible dietary intake required to meet maintenance (SL < ELF < PZB). Dietary ingredient composition did not significantly affect the digestible mineral supply required for maintenance (PZB) for any of the minerals (P, Mg, K, Cu and Zn) studied. However, ELF of micro-minerals such as Cu and Zn were significantly affected. The ELF of Cu was significantly lower and that of Zn was significantly higher in V group compared with M-fed fish. Further studies on the effects of such changes in dietary formulations on micro-mineral metabolism are warranted.
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Affiliation(s)
- P Antony Jesu Prabhu
- INRA, UR 1067, Nutrition, Metabolism and Aquaculture (NuMeA), Aquapôle, 64310, Saint-Pee-Sur-Nivelle, France
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15
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Nyasae LK, Schell MJ, Hubbard AL. Copper directs ATP7B to the apical domain of hepatic cells via basolateral endosomes. Traffic 2014; 15:1344-65. [PMID: 25243755 DOI: 10.1111/tra.12229] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/16/2014] [Indexed: 01/01/2023]
Abstract
Physiologic Cu levels regulate the intracellular location of the Cu ATPase ATP7B. Here, we determined the routes of Cu-directed trafficking of endogenous ATP7B in the polarized hepatic cell line WIF-B and in the liver in vivo. Copper (10 µm) caused ATP7B to exit the trans-Golgi network (TGN) in vesicles, which trafficked via large basolateral endosomes to the apical domain within 1 h. Although perturbants of luminal acidification had little effect on the TGN localization of ATP7B in low Cu, they blocked delivery to the apical membrane in elevated Cu. If the vesicular proton-pump inhibitor bafilomycin-A1 (Baf) was present with Cu, ATP7B still exited the TGN, but accumulated in large endosomes located near the coverslip, in the basolateral region. Baf washout restored ATP7B trafficking to the apical domain. If ATP7B was staged apically in high Cu, Baf addition promoted the accumulation of ATP7B in subapical endosomes, indicating a blockade of apical recycling, with concomitant loss of ATP7B at the apical membrane. The retrograde pathway to the TGN, induced by Cu removal, was far less affected by Baf than the anterograde (Cu-stimulated) case. Overall, loss of acidification-impaired Cu-regulated trafficking of ATP7B at two main sites: (i) sorting and exit from large basolateral endosomes and (ii) recycling via endosomes near the apical membrane.
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Affiliation(s)
- Lydia K Nyasae
- Department of Cell Biology, The Johns Hopkins School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 20184, USA
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16
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Wu X, Zhang T, Liu Z, Zheng J, Guo J, Yang F, Gao X. Effects of different sources and levels of copper on growth performance, nutrient digestibility, and elemental balance in young female mink (Mustela vison). Biol Trace Elem Res 2014; 160:212-21. [PMID: 24962642 DOI: 10.1007/s12011-014-0054-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 06/16/2014] [Indexed: 01/22/2023]
Abstract
An experiment was conducted in a 3 × 3 + 1 factorial experiment based on a completely randomized design to evaluate the effects of different sources of copper on growth performance, nutrient digestibility and elemental balance in young female mink on a corn-fishmeal-based diet. Animals in the control group were fed a basal diet (containing 8.05 mg Cu/kg DM; control), which mainly consisted of corn, fish meal, meat bone meal, and soybean oil, with no copper supplementation. Minks in other nine treatments were fed basal diets supplemented with Cu from reagent-grade copper sulfate, tribasic copper chloride (TBCC) and copper methionate. Cu concentrations of experiment diets were 10, 25, and 40 mg/kg copper. A metabolism trial of 4 days was conducted during the last week of experimental feeding. Final body weight and average daily gain increased (linear and quadratic, P < 0.05) as Cu increased in the diet; maximal growth was seen in the Cu25 group. Cu supplementation slightly improved the feed conversion rate (P = 0.095). Apparent fat digestibility was increased by copper level (P = 0.020). Retention nitrogen was increased by copper level (linear, P = 0.003). Copper source had a significant effect on copper retention with Cu-Met and copper sulfate treatments retention more than TBCC treatments (P < 0.05). Our results indicate that mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in mink, and mink can efficiently utilize Cu-Met and CuSO4.
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Affiliation(s)
- Xuezhuang Wu
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
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17
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Polishchuk EV, Concilli M, Iacobacci S, Chesi G, Pastore N, Piccolo P, Paladino S, Baldantoni D, van IJzendoorn SCD, Chan J, Chang CJ, Amoresano A, Pane F, Pucci P, Tarallo A, Parenti G, Brunetti-Pierri N, Settembre C, Ballabio A, Polishchuk RS. Wilson disease protein ATP7B utilizes lysosomal exocytosis to maintain copper homeostasis. Dev Cell 2014; 29:686-700. [PMID: 24909901 PMCID: PMC4070386 DOI: 10.1016/j.devcel.2014.04.033] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 03/15/2014] [Accepted: 04/29/2014] [Indexed: 12/24/2022]
Abstract
Copper is an essential yet toxic metal and its overload causes Wilson disease, a disorder due to mutations in copper transporter ATP7B. To remove excess copper into the bile, ATP7B traffics toward canalicular area of hepatocytes. However, the trafficking mechanisms of ATP7B remain elusive. Here, we show that, in response to elevated copper, ATP7B moves from the Golgi to lysosomes and imports metal into their lumen. ATP7B enables lysosomes to undergo exocytosis through the interaction with p62 subunit of dynactin that allows lysosome translocation toward the canalicular pole of hepatocytes. Activation of lysosomal exocytosis stimulates copper clearance from the hepatocytes and rescues the most frequent Wilson-disease-causing ATP7B mutant to the appropriate functional site. Our findings indicate that lysosomes serve as an important intermediate in ATP7B trafficking, whereas lysosomal exocytosis operates as an integral process in copper excretion and hence can be targeted for therapeutic approaches to combat Wilson disease.
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Affiliation(s)
- Elena V Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Mafalda Concilli
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Simona Iacobacci
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Giancarlo Chesi
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Nunzia Pastore
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Pasquale Piccolo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, Federico II University, Naples 80125, Italy
| | | | - Sven C D van IJzendoorn
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen 9713, the Netherlands
| | - Jefferson Chan
- Department of Chemistry and Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christopher J Chang
- Department of Chemistry and Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Angela Amoresano
- Department of Chemical Sciences, University of Naples Federico II, Napoli 80126, Italy
| | - Francesca Pane
- Department of Chemical Sciences, University of Naples Federico II, Napoli 80126, Italy
| | - Piero Pucci
- Department of Chemical Sciences, University of Naples Federico II, Napoli 80126, Italy
| | - Antonietta Tarallo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Giancarlo Parenti
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Dulbecco Telethon Institute, TIGEM, Naples 80131, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Roman S Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy.
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18
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Wu X, Liu Z, Zhang T, Yang Y, Yang F, Gao X. Effects of dietary copper on nutrient digestibility, tissular copper deposition and fur quality of growing-furring mink (Mustela vison). Biol Trace Elem Res 2014; 158:166-75. [PMID: 24668161 DOI: 10.1007/s12011-014-9933-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 03/04/2014] [Indexed: 11/29/2022]
Abstract
The present study investigated the effects of dietary copper (Cu) on growth performance and fur quality in growing-furring minks. One hundred and five standard dark female minks were randomly assigned to seven groups with the following dietary treatments: basal diet with no supplemental Cu (control) and basal diet supplemented with either 6, 12, 24, 48, 96 or 192 mg/kg Cu from copper sulphate, respectively. Our data showed that final body weight (P = 0.033), daily gain (P = 0.029) and fat digestibility (P = 0.0006) responded to increasing levels of Cu. The activity of glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in serum increased (linear and quadratic, P < 0.05) as Cu increased in the diet. Increasing Cu improved total protein (TP) and albumin (ALB) (quadratic, P < 0.05). The level of ceruloplasmin (CER) responded in a linear (P < 0.0001) and quadratic (P < 0.0001) form with increasing level of Cu. Colour intensity of those minks pelted suggested that relatively high levels of supplemental Cu have a beneficial effect on intensifying hair colour of dark mink but did not affect leather thickness. Liver Cu and plasma Cu concentrations of the mink linearly (P < 0.0001) responded to increasing levels of Cu. Our results indicate that growing-furring mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in growing-furring mink, and supplemental dietary Cu in growing-furring mink promotes fat digestion and improve hair colour.
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Affiliation(s)
- Xuezhuang Wu
- Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
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19
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Should I stay or should I go? Trafficking of sub-lytic MAC in the retinal pigment epithelium. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:267-74. [PMID: 24664707 DOI: 10.1007/978-1-4614-3209-8_34] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Assembly of sub-lytic C5b-9 membrane attack complexes (MAC) on the plasma membrane of retinal pigment epithelial cells contributes to the pathogenesis of age-related macular degeneration. C5b-9 pores induce calcium influx, which activates signaling pathways that compromise cell function. Mechanisms that limit sub-lytic MAC activity include: cell surface complement regulatory proteins CD46, CD55, and CD59 that inhibit specific steps of MAC formation; elimination of assembled MAC by exocytosis of membrane vesicles or by endocytosis and subsequent lysosomal degradation; and rapid resealing of pores by the exocytosis of lysosomes. Aging in the post-mitotic retinal pigment epithelium is characterized by the accumulation of cellular debris called lipofuscin, which has also been associated with retinal diseases such as age-related macular degeneration. Lipofuscin has been shown to activate complement components both in vitro and in vivo, suggesting that it could contribute complement-mediated dysfunction in the retinal pigment epithelium. Here, we discuss emerging evidence that vesicular trafficking in the retinal pigment epithelium is critical for efficient removal of MAC from the cell surface and for limiting inflammation in the outer retina.
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20
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Toops KA, Lakkaraju A. Let's play a game of chutes and ladders: Lysosome fusion with the epithelial plasma membrane. Commun Integr Biol 2013; 6:e24474. [PMID: 23986802 PMCID: PMC3742055 DOI: 10.4161/cib.24474] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 03/27/2013] [Indexed: 12/21/2022] Open
Abstract
In non-polarized cells, calcium-induced exocytosis of “conventional” lysosomes is important in diverse processes like membrane repair after exposure to pore-forming toxins and clearance of cellular debris. Resealing of torn membranes is especially critical for barrier epithelia that directly interact with pathogens and toxins, which can result in membrane microdisruptions and lesions. However, whether lysosomes participate in membrane repair in polarized epithelia has been an open question. We recently reported that in polarized Madin-Darby canine kidney (MDCK) cells, localized influx of calcium induces lysosomes to fuse with the basolateral membrane. This spatial segregation of exocytosis depends on an intact actin cytoskeleton, membrane cholesterol and restricted distribution of fusion machinery such as the t-SNARE syntaxin 4. Our data show that the polarity of syntaxin 4 (which is regulated by the clathrin adaptor protein AP-1) dictates whether lysosomes parachute down to the basolateral membrane or take a ladder up to the apical membrane. Here, we speculate about additional machinery (such as the lysosomal calcium sensor synaptotagmin VII and the v-SNARE VAMP7) that could be involved in polarized fusion of lysosomes with the epithelial membrane. We also discuss the potential importance of lysosome exocytosis in maintaining membrane integrity in the retinal pigment epithelium, the primary tissue affected in blinding diseases such as age-related macular degeneration.
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Affiliation(s)
- Kimberly A Toops
- Department of Ophthalmology and Visual Sciences; School of Medicine and Public Health; McPherson Eye Research Institute; University of Wisconsin-Madison; Madison, WI, USA
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21
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Linder MC. The relationship of copper to DNA damage and damage prevention in humans. Mutat Res 2013; 733:83-91. [PMID: 23463874 DOI: 10.1016/j.mrfmmm.2012.03.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Copper ions are well suited to facilitate formation of reactive oxygen species (ROS) that can damage biomolecules, including DNA and chromatin. That this can occur in vitro with isolated DNA or chromatin,or by exposure of cultured mammalian cells to copper complexed with various agents, has been well demonstrated. Whether that is likely to occur in vivo is not as clear. This review addresses the question of whether and how copper ions or complexes – in forms that could be present in vivo, damage DNA and chromosome structure and/or promote epigenetic changes that can lead to pathology and diseases, including cancer and neurological conditions such as Alzheimer's disease, Lewy body dementias, and spongiform encephalopathies. This question is considered in light of our knowledge that copper-dependent enzymes are important contributors to antioxidant defense, and that the mammalian organism has robust mechanisms for maintaining constant levels of copper not only in body fluids but in its major organs. Overall,and except in unusual genetic states that lead to copper overload in specific cells (particularly those in liver), it appears that excessive intake of copper is not a significant factor in the development of disease states.
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Affiliation(s)
- Maria C Linder
- Department of Chemistry and Biochemistry, California State University, Fullerton, CA 92834-6866, USA.
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22
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Qin Z, Lai B, Landero J, Caruso JA. Coupling transmission electron microscopy with synchrotron radiation X-ray fluorescence microscopy to image vascular copper. JOURNAL OF SYNCHROTRON RADIATION 2012; 19:1043-1049. [PMID: 23093768 DOI: 10.1107/s090904951203405x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 07/30/2012] [Indexed: 06/01/2023]
Abstract
Recently, using synchrotron radiation X-ray fluorescence microscopy (SRXRF), the copper accumulation in rat aortic elastin and copper topography in human THP-1 cell monolayer have been described. However, it is necessary to locate more accurately cellular copper in the vascular cells and tissues. In the current study, SRXRF coupling with transmission electron microscopy (TEM) was used to image copper in sections of human THP-1 cells and mouse aorta. The results showed that sections of 1 µm thickness are required for SRXRF producing a correlative image with TEM between copper topography and cellular ultrastructure. As compared with SRXRF alone, coupling TEM with SRXRF can clearly identify the location of copper in the nucleus and nucleolus in non-dividing THP-1 cell sections, and can differentiate the copper location at elastic laminae from collagen in mouse aortic sections. Thus, these results revealed new information about the copper topography in vascular cells and tissues and highlighted the potential of TEM-SRXRF to investigate the role of copper in macrophage and aortic homeostasis.
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Affiliation(s)
- Zhenyu Qin
- Division of Vascular Surgery, Department of Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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23
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Xu J, Toops KA, Diaz F, Carvajal-Gonzalez JM, Gravotta D, Mazzoni F, Schreiner R, Rodriguez-Boulan E, Lakkaraju A. Mechanism of polarized lysosome exocytosis in epithelial cells. J Cell Sci 2012; 125:5937-43. [PMID: 23038769 DOI: 10.1242/jcs.109421] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fusion of lysosomes with the plasma membrane is a calcium-dependent process that is crucial for membrane repair, limiting pathogen entry and clearing cellular debris. In non-polarized cells, lysosome exocytosis facilitates rapid resealing of torn membranes. Here, we investigate the mechanism of lysosome exocytosis in polarized epithelia, the main barrier between the organism and the external environment and the first line of defense against pathogens. We find that in polarized Madin-Darby canine kidney (MDCK) cells, calcium ionophores or pore-forming toxins cause lysosomes to fuse predominantly with the basolateral membrane. This polarized exocytosis is regulated by the actin cytoskeleton, membrane cholesterol and the clathrin adaptor AP-1. Depolymerization of actin, but not microtubules, causes apical lysosome fusion, supporting the hypothesis that cortical actin is a barrier to exocytosis. Overloading lysosomes with cholesterol inhibits exocytosis, suggesting that excess cholesterol paralyzes lysosomal traffic. The clathrin adaptor AP-1 is responsible for accurately targeting syntaxin 4 to the basolateral domain. In cells lacking either the ubiquitous AP-1A or the epithelial-specific AP-1B, syntaxin 4 is non-polar. This causes lysosomes to fuse with both the apical and basolateral membranes. Consistent with these findings, RNAi-mediated depletion of syntaxin 4 inhibits basolateral exocytosis in wild-type MDCK, and both apical and basolateral exocytosis in cells lacking AP-1A or AP-1B. Our results provide fundamental insight into the molecular machinery involved in membrane repair in polarized epithelia and suggest that AP-1 is a crucial regulator of this process.
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Affiliation(s)
- Jin Xu
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
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24
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25
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Yanagimoto C, Harada M, Kumemura H, Abe M, Koga H, Sakata M, Kawaguchi T, Terada K, Hanada S, Taniguchi E, Ninomiya H, Ueno T, Sugiyama T, Sata M. Copper incorporation into ceruloplasmin is regulated by Niemann-Pick C1 protein. Hepatol Res 2011; 41:484-91. [PMID: 21518405 DOI: 10.1111/j.1872-034x.2011.00788.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AIM Wilson disease is a genetic disorder of copper metabolism characterized by impaired biliary copper excretion. Wilson disease gene product (ATP7B) functions in copper incorporation to ceruloplasmin (Cp) and biliary copper excretion. Our previous study showed the late endosome localization of ATP7B and described the copper transport pathway from the late endosome to trans-Golgi network (TGN). However, the cellular localization of ATP7B and copper metabolism in hepatocytes remains controversial. The present study was performed to evaluate the role of Niemann-Pick type C (NPC) gene product NPC1 on intracellular copper transport in hepatocytes. METHODS We induced the NPC phenotype using U18666A to modulate the vesicle traffic from the late endosome to TGN. Then, we examined the effect of NPC1 overexpression on the localization of ATP7B and secretion of holo-Cp, a copper-binding mature form of Cp. RESULTS Overexpression of NPC1 increased holo-Cp secretion to culture medium of U18666A-treated cells, but did not affect the secretion of albumin. Manipulation of NPC1 function affected the localization of ATP7B and late endosome markers, but did not change the localization of a TGN marker. ATP7B co-localized with the late endosome markers, but not with the TGN marker. CONCLUSION These findings suggest that ATP7B localizes in the late endosomes and that copper in the late endosomes is transported to the secretory compartment via an NPC1-dependent pathway and incorporated into Cp.
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Affiliation(s)
- Chikatoshi Yanagimoto
- Division of Gastroenterology, Department of Medicine and Research Center for Innovative Cancer Therapy of the 21st Century COE Program for Medical Science, Kurume University School of Medicine, Kurume Yanagimoto-naika, Itoshima The Third Department of Internal Medicine, University of Occupational and Environmental Health, Japan School of Medicine, Kitakyushu Department of Medicine, Onoba Hospital Biochemistry, Akita University School of Medicine, Akita Department of Neurobiology, Tottori University Faculty of Medicine, Yonago, Japan
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Sarkar B, Roberts EA. The puzzle posed by COMMD1, a newly discovered protein binding Cu(ii). Metallomics 2011; 3:20-7. [DOI: 10.1039/c0mt00031k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Bervoets AR, Behets GJ, Schryvers D, Roels F, Yang Z, Verberckmoes SC, Damment SJ, Dauwe S, Mubiana VK, Blust R, De Broe ME, D'Haese PC. Hepatocellular transport and gastrointestinal absorption of lanthanum in chronic renal failure. Kidney Int 2009; 75:389-98. [DOI: 10.1038/ki.2008.571] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yanagimoto C, Harada M, Kumemura H, Koga H, Kawaguchi T, Terada K, Hanada S, Taniguchi E, Koizumi Y, Koyota S, Ninomiya H, Ueno T, Sugiyama T, Sata M. Niemann-Pick C1 protein transports copper to the secretory compartment from late endosomes where ATP7B resides. Exp Cell Res 2009; 315:119-26. [PMID: 19007772 DOI: 10.1016/j.yexcr.2008.10.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 08/28/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
Abstract
Wilson disease is a genetic disorder characterized by the accumulation of copper in the body by defective biliary copper excretion. Wilson disease gene product (ATP7B) functions in copper incorporation to ceruloplasmin (Cp) and biliary copper excretion. However, copper metabolism in hepatocytes has been still unclear. Niemann-Pick disease type C (NPC) is a lipid storage disorder and the most commonly mutated gene is NPC1 and its gene product NPC1 is a late endosome protein and regulates intracellular vesicle traffic. In the present study, we induced NPC phenotype and examined the localization of ATP7B and secretion of holo-Cp, a copper-binding mature form of Cp. The vesicle traffic was modulated using U18666A, which induces NPC phenotype, and knock down of NPC1 by RNA interference. ATP7B colocalized with the late endosome markers, but not with the trans-Golgi network markers. U18666A and NPC1 knock down decreased holo-Cp secretion to culture medium, but did not affect the secretion of other secretory proteins. Copper accumulated in the cells after the treatment with U18666A. These findings suggest that ATP7B localizes in the late endosomes and that copper in the late endosomes is transported to the secretory compartment via NPC1-dependent pathway and incorporated into apo-Cp to form holo-Cp.
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Affiliation(s)
- Chikatoshi Yanagimoto
- Division of Gastroenterology, Department of Medicine and Research Center for Innovative Cancer Therapy of the 21st Century COE Program for Medical Science, Kurume University School of Medicine, Kurume, Japan.
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Damment SJP, Pennick M. Clinical pharmacokinetics of the phosphate binder lanthanum carbonate. Clin Pharmacokinet 2008; 47:553-63. [PMID: 18698878 DOI: 10.2165/00003088-200847090-00001] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Lanthanum carbonate is considered to be the most potent of a new generation of noncalcium phosphate binders used to treat hyperphosphataemia in chronic kidney disease (CKD), a condition associated with progressive bone and cardiovascular pathology and a markedly elevated risk of death. Its phosphate-binding action involves ionic binding and precipitation of insoluble complexes within the lumen of the intestine, thereby preventing absorption of dietary phosphate. While pharmacokinetics have little relevance to the efficacy of lanthanum carbonate, they are of fundamental importance when it comes to evaluating safety. When administered as lanthanum carbonate, the oral bioavailability of lanthanum is low (approximately 0.001%). The small absorbed fraction is excreted predominantly in bile, with less than 2% being eliminated by the kidneys. Predictably, therefore, plasma exposure and pharmacokinetics have been shown to be similar in healthy human volunteers and CKD stage 5 patients. With almost complete plasma protein binding, free lanthanum concentrations in patients at steady state are <3 pg/mL. These properties greatly reduce systemic exposure, tissue deposition and the potential for adverse effects. While lanthanum has a variety of calcium-like actions in vitro, there is little or no evidence that these occur in vivo. This paradox is explained by the very low concentrations of circulating free lanthanum ions, which are many orders of magnitude lower than reported effect concentrations in vitro. Safety pharmacology and toxicology evaluations have failed to reveal any significant calcium-like actions in vivo, despite inclusion of high intravenous doses in some cases.Lanthanum carbonate has a low propensity to cause systemic drug interactions due to its poor absorption. However, the higher concentrations present in the gastrointestinal tract can form chelates with some drugs, such as fluoroquinolones, and reduce their absorption. The improved understanding of the pharmacokinetics of lanthanum that has emerged in recent years has helped to explain why the myriad of calcium-like effects described in vitro for lanthanum have little if any relevance in vivo. The pharmacokinetic investigations of lanthanum carbonate formed an important part of the stringent premarketing safety assessment process and have been influential in reassuring both regulators and physicians that the agent can be used safely and effectively in this vulnerable dialysis population.
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Weiss KH, Lozoya JC, Tuma S, Gotthardt D, Reichert J, Ehehalt R, Stremmel W, Füllekrug J. Copper-induced translocation of the Wilson disease protein ATP7B independent of Murr1/COMMD1 and Rab7. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:1783-94. [PMID: 18974300 DOI: 10.2353/ajpath.2008.071134] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Wilson disease is a genetic disorder of copper metabolism. Impaired biliary excretion results in a gradual accumulation of copper, which leads to severe disease. The specific gene defect lies in the Wilson disease protein, ATP7B, a copper-transporting ATPase that is highly active in hepatocytes. The two major functions of ATP7B in the liver are the copper loading of ceruloplasmin in the Golgi apparatus, and the excretion of excess copper into the bile. In response to elevated copper levels, ATP7B shows a unique intracellular trafficking pattern that is required for copper excretion from the Golgi apparatus into dispersed vesicles. We analyzed the translocation of ATP7B by both confocal microscopy and RNA interference, testing current models that suggest the involvement of Murr1/COMMD1 and Rab7 in this pathway. We found that although the ATP7B translocation is conserved among nonhepatic cell lines, there is no co-localization with Murr1/COMMD1 or the Rab marker proteins of the endolysosomal system. Consistent with this finding, the translocation of ATP7B was not impaired by the depletion of either Murr1/COMMD1 or Rab7, or by a dominant-negative Rab7 mutant. In conclusion, our data suggest that the translocation of ATP7B takes place independently of Rab7-regulated endosomal traffic events. Murr1/COMMD1 plays a role in a later step of the copper excretion pathway but is not involved in the translocation of the Wilson disease protein.
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Affiliation(s)
- Karl Heinz Weiss
- Department of Gastroenterology, University Hospital Heidelberg, Heidelberg, Germany
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Jalil YA, Ritz V, Jakimenko A, Schmitz-Salue C, Siebert H, Awuah D, Kotthaus A, Kietzmann T, Ziemann C, Hirsch-Ernst KI. Vesicular localization of the rat ATP-binding cassette half-transporter rAbcb6. Am J Physiol Cell Physiol 2008; 294:C579-90. [PMID: 18160489 DOI: 10.1152/ajpcell.00612.2006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The clarification of subcellular localization represents an important basis toward characterization of ATP-binding cassette (ABC) transporters and resolution of their roles in cellular physiology. Rat Abcb6 (rAbcb6) is a membrane-situated half-transporter belonging to the ABC protein superfamily. To investigate rAbcb6 subcellular distribution, the human colon adenocarcinoma line LoVo, which we found to be devoid of endogenous human ABCB6 mRNA, was employed for heterologous expression of rAbcb6 bearing a COOH-terminal epitope tag (rAbcb6-V5). Following subcellular fractionation, rAbcb6-V5 was observed as an N-glycosylated protein in fractions enriched with lysosomal/endosomal membrane proteins. Indirect immunofluorescence analyses of rAbcb6-V5 using antibodies against a rAbcb6-specific peptide or against the V5-tag revealed a punctate pattern that was colocalized with lysosome-associated membrane protein 1 (LAMP1), a marker of lysosomes/late endosomes. Substantial colocalization of tagged rAbcb6 with lysosomal/late endosomal marker was confirmed with living, unfixed LoVo cells coexpressing rAbcb6 fused to enhanced green fluorescent protein. Vesicular distribution in LoVo cells was consistent with localization of endogenous rAbcb6 expressed in rat primary hepatocyte cultures or in liver sections, as revealed by overlap of rat Lamp1 with rAbcb6 in double immunofluorescence analyses. Since several Abcb6-related half-transporters confer heavy metal tolerance, we investigated whether rAbcb6 expression in LoVo cells might affect sensitivity toward transition metal toxicity. Applying MTT viability assays, we found that expression of either rAbcb6-V5 or untagged rAbcb6 conferred tolerance toward copper, but not to cobalt or zinc. In summary, these results demonstrate that rAbcb6 is a glycosylated protein targeted to intracellular vesicular membranes and suggest involvement of rAbcb6 in transition metal homeostasis.
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Affiliation(s)
- Youssef Abdul Jalil
- Institute of Pharmacology and Toxicology, University of Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen, Germany
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Gonzalez MA, Alvarez MDL, Pisani GB, Bernal CA, Roma MG, Carrillo MC. Involvement of oxidative stress in the impairment in biliary secretory function induced by intraperitoneal administration of aluminum to rats. Biol Trace Elem Res 2007; 116:329-48. [PMID: 17709913 DOI: 10.1007/bf02698017] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 11/30/1999] [Accepted: 10/24/2006] [Indexed: 10/22/2022]
Abstract
We have shown that aluminum (Al) induces cholestasis associated with multiple alterations in hepatocellular transporters involved in bile secretory function, like Mrp2. This work aims to investigate whether these harmful effects are mediated by the oxidative stress caused by the metal. For this purpose, the capability of the antioxidant agent, vitamin E, to counteract these alterations was studied in male Wistar rats. Aluminum hydroxide (or saline in controls) was administered ip (27 mg/kg body weight, three times a week, for 90 d). Vitamin E (600 mg/kg body weight) was coadministered, sc. Al increased lipid peroxidation (+50%) and decreased hepatic glutation levels (-43%) and the activity of glutation peroxidase (-50%) and catalase (-88%). Vitamin E counteracted these effects total or partially. Both plasma and hepatic Al levels reached at the end of the treatment were significantly reduced by vitamin E (-40% and -44%, respectively; p<0.05). Al increased 4 times the hepatic apoptotic index, and this effect was fully counteracted by vitamin E. Bile flow was decreased in Altreated rats (-37%) and restored to normality by vitamin E. The antioxidant normalized the hepatic handling of the Mrp2 substrates, rose bengal, and dinitrophenyl-S-glutathione, which was causally associated with restoration of Mrp2 expression. Our data indicate that oxidative stress has a crucial role in cholestasis, apoptotic/necrotic hepatocellular damage, and the impairment in liver transport function induced by Al and that vitamin E counteracts these harmful effects not only by preventing free-radical formation but also by favoring Al disposal.
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Affiliation(s)
- Marcela A Gonzalez
- Cátedra de Fisiología Humana, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Paraje El Pozo, Santa Fe, Argentina
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Harada M, Kawaguchi T, Kumemura H, Terada K, Ninomiya H, Taniguchi E, Hanada S, Baba S, Maeyama M, Koga H, Ueno T, Furuta K, Suganuma T, Sugiyama T, Sata M. The Wilson disease protein ATP7B resides in the late endosomes with Rab7 and the Niemann-Pick C1 protein. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 166:499-510. [PMID: 15681833 PMCID: PMC1602322 DOI: 10.1016/s0002-9440(10)62272-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Wilson disease is a genetic disorder characterized by the accumulation of copper in the body due to a defect of biliary copper excretion. Although the Wilson disease gene has been cloned, the cellular localization of the gene product (ATP7B) has not been fully clarified. Therefore, the precise physiological action of ATP7B is still unknown. We examined the distribution of ATP7B using an anti-ATP7B antibody, green fluorescent protein (GFP)-ATP7B (GFP-ATP7B) and ATP7B-DsRed in various cultured cells. Intracellular organelles were visualized by fluorescence microscopy. The distribution of ATP7B was compared with that of Rab7 and Niemann-Pick C1 (NPC1), proteins that localize in the late endosomes. U18666A, which induces the NPC phenotype, was used to modulate the intracellular vesicle traffic. GFP-ATP7B colocalized with various late endosome markers including Rab7 and NPC1 but not with Golgi or lysosome markers. U18666A induced the formation of late endosome-lysosome hybrid organelles, with GFP-ATP7B localized with NPC1 in these structures. We have confirmed that ATP7B is a late endosome-associated membrane protein. ATP7B appears to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes. Thus, defective copper ATPase activity of ATP7B in the late endosomes appears to be the main defect of Wilson disease.
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Affiliation(s)
- Masaru Harada
- Second Department of Medicine, Kurume University School of Medicine, 67 Asahi-Machi, Kurume 830-0011, Japan.
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35
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Cater MA, Mercer JF. Copper in mammals: mechanisms of homeostasis and pathophysiology. TOPICS IN CURRENT GENETICS 2005. [DOI: 10.1007/4735_101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Abstract
Cu is an essential nutrient that is required for a broad range of cellular and molecular processes. Mammals have efficient systems to control Cu homeostasis that operate at the level of controlling uptake, distribution, sequestration and excretion of Cu. The study of diseases associated with disturbed Cu homeostasis has greatly enhanced our understanding of the molecular mechanisms involved in Cu metabolism. In man the liver is responsible for excreting excess Cu from the body by means of biliary secretion. Wilson disease is a severe human disorder characterized by Cu accumulation in the liver as a result of a deficiency in biliary Cu secretion. This disorder is caused by mutations in the gene that encodes a Cu-transporting P-type ATPase (ATP7B). The MURR1 gene was identified recently, and it was hypothesized that this gene is also essential for biliary Cu excretion and is presumed to act downstream of ATP7B. MURR1 is mutated in canine Cu toxicosis, a disorder with phenotypic characteristics similar to those of Wilson disease. MURR1 encodes a protein that is of unknown function and is without detectable sequence homology to known proteins. MURR1 is readily detected in all tissues and cell types, suggesting that it may exhibit a pleiotropic function in different organs, which may or may not be exclusively linked to Cu homeostasis. The use of genetic, biochemical and genomic tools, as well as the development of appropriate models in organisms other than dog, will allow the elucidation of the molecular and cellular function of MURR1 in relation to hepatic Cu homeostasis and biliary Cu excretion.
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Affiliation(s)
- Cisca Wijmenga
- Department of Biomedical Genetics, University Medical Center, Stratenum 2.117, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
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Klomp AEM, van de Sluis B, Klomp LWJ, Wijmenga C. The ubiquitously expressed MURR1 protein is absent in canine copper toxicosis. J Hepatol 2003; 39:703-9. [PMID: 14568250 DOI: 10.1016/s0168-8278(03)00380-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Copper toxicosis (CT) in Bedlington terriers is an autosomal recessive disorder characterized by massive lysosomal copper accumulation in livers of affected dogs, and a defect in the biliary excretion of this metal. We propose that MURR1, the gene defective in canine CT, has a role in the regulation of copper excretion into bile during copper overload. METHODS Polyclonal antibodies raised against full-length recombinant human MURR1 were used for immunoblot analysis and indirect immunofluorescence studies. RESULTS Using Western blot analysis, these antibodies abundantly detected MURR1 as a 23 kDa protein in liver extracts of mice and dogs, but MURR1 was undetectable in the livers of affected Bedlington terriers. MURR1 was also detected in different tissues and cell lines; in cell lines the protein was found both in cytosol and membrane preparations. Consistent with this observation, indirect immunofluorescence staining revealed that in some cells MURR1 was associated with a vesicular compartment diffusely localized throughout the cell. CONCLUSIONS The genomic deletion in MURR1 results in complete absence of MURR1 protein. Based on the unanticipated subcellular localization, our results suggest a role for MURR1 in the regulation of vesicular copper sequestration during copper overload.
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Affiliation(s)
- Adriana E M Klomp
- Department of Metabolic and Endocrinic Diseases, University Medical Center Utrecht, room KC02.069.1, Utrecht University, Lundlaan 6, 3584 EA Utrecht, The Netherlands
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Fuentealba IC, Aburto EM. Animal models of copper-associated liver disease. COMPARATIVE HEPATOLOGY 2003; 2:5. [PMID: 12769823 PMCID: PMC156612 DOI: 10.1186/1476-5926-2-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2003] [Accepted: 04/03/2003] [Indexed: 01/29/2023]
Abstract
Recent advances in molecular biology have made possible the identification of genetic defects responsible for Wilson's disease, Indian childhood cirrhosis and copper toxicosis in Long Evans Cinnamon rats, toxic milk mice, and Bedlington terriers. The Wilson's disease gene is localized on human chromosome 13 and codes for ATP7B, a copper transporting P-type ATPase. A genetic defect similar to that of Wilson's disease occurs in Long Evans Cinnamon rats and toxic milk mice. Familial copper storage disorders in Bedlington and West Highland white terriers are associated with early subclinical disease, and copper accumulation with subsequent liver injury culminating in cirrhosis. The canine copper toxicosis locus in Bedlington terriers has been mapped to canine chromosome region CFA 10q26. Recently, a mutated MURR1 gene was discovered in Bedlington terriers affected with the disease. Idiopathic childhood cirrhosis is biochemically similar to copper toxicosis in Bedlington terriers, but clinically much more severe. Both conditions are characterized by the absence of neurologic damage and Kayser-Fleisher rings, and normal ceruloplasmin levels. A recent study added North Ronaldsay sheep to the list of promising animal models to study Indian childhood cirrhosis. Morphologic similarities between the two conditions include periportal to panlobular copper retention and liver changes varying from active hepatitis to panlobular pericellular fibrosis, and cirrhosis. Certain copper-associated disorders, such as chronic active hepatitis in Doberman pinschers and Skye terrier hepatitis are characterized by copper retention secondary to the underlying disease, thus resembling primary biliary cirrhosis in humans. Copper-associated liver disease has increasingly being recognized in Dalmatians. Copper-associated liver diseases in Dalmatians and Long Evans Cinnamom rats share many morphologic features. Fulminant hepatic failure in Dalmatians is characterized by high serum activities of alanine aminotransferase and aspartate aminotransferase, and severe necrosis of centrilobular areas (periacinar, zone 3) hepatocytes. Macrophages and surviving hepatocytes contain copper-positive material. Liver disease associated with periacinar copper accumulation has also been described in Siamese cats. Many questions regarding copper metabolism in mammals, genetic background, pathogenesis and treatment of copper-associated liver diseases remain to be answered. This review describes the similarities between the clinico-pathological features of spontaneous copper-associated diseases in humans and domestic animals.
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Affiliation(s)
- I Carmen Fuentealba
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
| | - Enrique M Aburto
- Facultad de Medicina Veterinaria, Universidad Nacional Autonoma de Mexico, Ciudad de Mexico, Mexico
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Santon A, Sturniolo GC, Albergoni V, Irato P. Metallothionein-1 and metallothionein-2 gene expression and localisation of apoptotic cells in Zn-treated LEC rat liver. Histochem Cell Biol 2003; 119:301-8. [PMID: 12684815 DOI: 10.1007/s00418-003-0515-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2003] [Indexed: 10/25/2022]
Abstract
The aims of the present work were to determine the effect of long-term treatment with zinc (Zn) on metallothionein (MT) concentrations and to study the levels of both MT-1 and MT-2 mRNAs in Long-Evans Cinnamon (LEC) rat liver. We also identified apoptotic cells comparing two cytochemical techniques. Thirteen rats received 50 mg zinc acetate daily by gavage, 13 rats received no treatment, and both groups were killed after 60 days. Finally four rats were killed 35 days after birth (T(0)). The results demonstrate that the Zn-treated group had higher levels of MT than both the untreated and basal ones. Quantification of mRNA indicates that the level of the Zn-treated group was significantly higher than the untreated group. Confocal fluorescent staining with monoclonal antibody (Mab) against single-strand DNA localised the hepatic cells that had chromatin condensation and nuclear fragmentation typical of apoptosis, especially in the untreated group sections. The intensity and quantity of fluorescence decreased in both the treated and basal groups. The higher sensitivity of Mab staining compared to TUNEL, which revealed both apoptotic and necrotic cells, reflects the different action mechanism of the two techniques. These findings confirm, in LEC rats, the important role of Zn in cellular protection in relation to MT expression and apoptotic processes as cellular responses to DNA damage by free radicals.
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Affiliation(s)
- Alessandro Santon
- Department of Biology, University of Padova, via U. Bassi, 58/B, 35131 Padova, Italy
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Abstract
Transition metals are essential for health, forming integral components of proteins involved in all aspects of biological function. However, in excess these metals are potentially toxic, and to maintain metal homeostasis organisms must tightly coordinate metal acquisition and excretion. The diet is the main source for essential metals, but in aquatic organisms an alternative uptake route is available from the water. This review will assess physiological, pharmacological and recent molecular evidence to outline possible uptake pathways in the gills and intestine of teleost fish involved in the acquisition of three of the most abundant transition metals necessary for life; iron, copper, and zinc.
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Affiliation(s)
- Nicolas R Bury
- King's College London, School of Health and Life Sciences, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NN, UK.
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Cañizares F, Miras M, Serrano E, Díaz J, Tornel PL, Pons JA, Martínez P, Parrilla P. Copper metabolism and biliary secretion in patients receiving orthotopic liver transplantation. Clin Chim Acta 2002; 317:47-54. [PMID: 11814457 DOI: 10.1016/s0009-8981(01)00739-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND The quantitative aspects of biliary copper excretion in health and disease have not been fully defined yet. The aim of the study was to evaluate copper metabolism and biliary excretion of patients who have received an orthotopic liver transplant (OLT) during the immediate postoperative period. METHODS We have studied retrospectively 16 patients undergoing primary OLT and eight undergoing cholecystectomy, and measured serum concentration of copper and its secretion in bile and urine by flame atomic absorption spectrometry (FAAS). RESULTS We found a progressive increase of biliary copper secretion rates and a corresponding lowering of urinary copper during the postoperative period. Thus, in OLT patients, the mean of biliary copper secretion on day 1 is 0.7+/-0.2 micromol/day compared with 2.3+/-1.1 micromol/day on day 7 (p<0.01) and 6.1+/-2.5 micromol/day on day 15 (p<0.0001). The rate of copper output on day 5 after surgery is about one sixth of the value reported for patients who had undergone cholecystectomy. In patients suffering an acute rejection episode, there was an abrupt fall in bile flow (<15 ml/day) and excretion of biliary copper (<1 micromol/day), accompanied by an increase of urine copper excretion (>3 micromol/day), and both were recovered when the rejection episode was solved. We found an inverse relationship between the serum bilirubin (Bt), alkaline phosphatase (ALP) and the biliary copper excretion (p<0.01), and a direct relationship with urinary copper excretion (p<0.01). CONCLUSIONS The copper measurements in urine and bile are non-invasive techniques, of low cost, rapid and easy to accomplish, and available in hospitals accredited for hepatic transplantation. These characteristics make these methods helpful in the monitoring of patients submitted to OLT for assessment of graft quality and subsequent outcome.
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Affiliation(s)
- F Cañizares
- Department of Clinical Chemistry, University Hospital, "Virgen de la Arrixaca", Murcia, Spain.
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Aburto EM, Cribb AE, Fuentealba IC, Ikede BO, Kibenge FS, Markham F. Morphological and biochemical assessment of the liver response to excess dietary copper in Fischer 344 rats. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2001; 65:97-103. [PMID: 11346262 PMCID: PMC1189655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The aim of this study was to determine the amount of excess dietary copper (Cu) necessary to experimentally induce liver lesions characteristic of Cu-associated disease in Fischer 344 rats. Male weanling Fischer 344 rats of uniform age were divided into 6 groups (n = 5) and fed a rodent diet containing 18 (control), 750, 1000, 1250, 1500, and 2000 microg/g Cu added as CuSO4. Rats were euthanized after 3 months on the experimental diets and their livers processed for histology, histochemistry, Cu analysis (by atomic absorption spectrophotometry), and quantification of malondialdehyde (MDA) by the thiobarbituric acid reaction. Hepatic Cu levels were significantly higher (P < 0.01) in rats receiving over 1000 microg/g Cu compared to the controls (means for each diet: control = 4.8 microg/g, 750 microg/g Cu = 39.6 microg/g, 1000 microg/g Cu = 111.2 microg/g, 1250 microg/g Cu = 389 microg/g, 1500 microg/g Cu = 509.4 microg/g, and 2000 microg/g Cu = 766 microg/g). Histological lesions increased gradually according to the level of dietary Cu. Significant morphologic changes (necrosis, portal inflammation, hyaline remnants) and reduced growth rate occurred in rats receiving over 1250 microg/g Cu. However, no significant differences were found for MDA levels between groups. The present study demonstrates that compared to other species, very high levels of excess dietary Cu are needed to induce significant liver injury in Fischer 344 rats. Increased MDA content was not detected in rats with morphologic evidence of liver damage, suggesting that lipid peroxidation may not play a major role in this model of Cu toxicity.
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Affiliation(s)
- E M Aburto
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown
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43
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Grosell M, McGeer JC, Wood CM. Plasma copper clearance and biliary copper excretion are stimulated in copper-acclimated trout. Am J Physiol Regul Integr Comp Physiol 2001; 280:R796-806. [PMID: 11171660 DOI: 10.1152/ajpregu.2001.280.3.r796] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nonacclimated and Cu-acclimated rainbow trout (Oncorhynchus mykiss) exhibited equally rapid clearance of a single bolus of injected (64)Cu (3,780 nmol/kg) from the plasma (32-40 min to half- concentration). Eight hours after Cu injection, approximately 80% of the injected Cu was found in the liver. However, when Cu labeled with (64)Cu was presented intravascularly via continuous infusion at a rate of 158 nmol x kg(-1) x h(-1) for 72 h, Cu-acclimated fish cleared plasma Cu more effectively than nonacclimated fish. The use of chronically implanted cystic bile duct cannulas revealed a fourfold increase in hepatobiliary Cu excretion in Cu-acclimated fish during infusion, demonstrating the important homeostatic role of the liver in Cu metabolism. Extrahepatobiliary Cu excretion, likely through the gills and apparently exceeding biliary Cu excretion, was evident from appearance of (64)Cu in the ambient water but was not altered by Cu acclimation. Cu accumulation in white muscle also played an important a role in copper homeostasis.
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Affiliation(s)
- M Grosell
- McMaster University, Department of Biology, Hamilton, Ontario L8S 4K1, Canada.
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44
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Harada M, Sakisaka S, Terada K, Kimura R, Kawaguchi T, Koga H, Kim M, Taniguchi E, Hanada S, Suganuma T, Furuta K, Sugiyama T, Sata M. A mutation of the Wilson disease protein, ATP7B, is degraded in the proteasomes and forms protein aggregates. Gastroenterology 2001; 120:967-74. [PMID: 11231950 DOI: 10.1053/gast.2001.22543] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Wilson disease is a genetic disorder characterized by the accumulation of copper in the body as a result of a defect of copper excretion from hepatocytes. The intracellular localization of the Wilson disease gene product, ATP7B, was recently identified as the late endosomes. Various mutations have been documented in patients with Wilson disease. The clinical manifestations vary greatly among the patients; however, there is little information on the genotype-phenotype correlation. METHODS We investigated the distribution of a common ATP7B mutant His1069Gln and a mutant Asp1270Ser by expressing the mutants tagged with green fluorescent protein in Huh7 and HEK293 cells. Intracellular organelles were visualized by fluorescence microscopy. RESULTS Although the wild-type ATP7B and Asp1270Ser mutant localized in the late endosomes, His1069Gln mutant did not locate in the late endosomes and was degraded by the proteasomes in the cytoplasm. Furthermore, His1069Gln formed aggresomes composed of the degradates and intermediate filaments at the microtubule-organizing center. These aggresomes were similar to Mallory bodies on electron microscopy. CONCLUSIONS The different protein properties of ATP7B mutants may explain the variety of clinical spectrums in patients with Wilson disease.
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Affiliation(s)
- M Harada
- Second Department of Medicine, Kurume University School of Medicine, Kurume, Japan
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45
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Rahner C, Stieger B, Landmann L. Apical endocytosis in rat hepatocytes In situ involves clathrin, traverses a subapical compartment, and leads to lysosomes. Gastroenterology 2000; 119:1692-707. [PMID: 11113091 DOI: 10.1053/gast.2000.20233] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS This study demonstrates and characterizes apical (canalicular) endocytic pathways in hepatocytes in situ. METHODS Endocytic markers were administered by retrograde infusion through the common bile duct. Colocalization with proteins that are specific for various endocytic compartments was performed on stacks of deconvoluted confocal immunofluorescence images. The subcellular distribution of marker proteins was assessed by electron microscopy (EM). RESULTS Bulk-phase, as well as membrane-associated markers, were internalized readily at the apical cell pole. At the EM level, marker was found initially in 60-100-nm tubulovesicular structures and 150-200-nm cup-shaped vesicles, whereas multivesicular bodies and lysosomes became labeled after longer time intervals. Apical endocytosis involved clathrin and delivered marker to late endosomes (rab7(+), cathepsin D(+)), as well as lysosomes (rab7(-), cathepsin D(+)). Simultaneous labeling of the basolateral endocytic route resulted in overlap of both pathways in the late endosomal and lysosomal compartments. In addition, apical endocytosis involved a subapical compartment (endolyn-78(+), rab11(+), polymeric IgA receptor [pIgA-R(+)]) that is passed by the transcytotic route, thus constituting a crossroads. pIgA-R immunoreactivity, probably reflecting the cleaved receptor fragment, was associated with apical endocytic marker and colocalized with clathrin and later with cathepsin D. CONCLUSIONS Apical endocytosis involves coated pits/vesicles, leads to a subapical compartment, and plays a role in the retrieval of canalicular plasma membrane components for lysosomal degradation.
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Affiliation(s)
- C Rahner
- Department of Anatomy, University of Basel, Basel, Switzerland
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46
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Harada M, Sakisaka S, Kawaguchi T, Kimura R, Taniguchi E, Koga H, Hanada S, Baba S, Furuta K, Kumashiro R, Sugiyama T, Sata M. Copper does not alter the intracellular distribution of ATP7B, a copper-transporting ATPase. Biochem Biophys Res Commun 2000; 275:871-6. [PMID: 10973814 DOI: 10.1006/bbrc.2000.3403] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Wilson's disease is a genetic disorder characterized by the accumulation of copper in the body due to a defect of biliary copper excretion. However, the mechanism of biliary copper excretion has not been fully clarified. We examined the effect of copper on the intracellular localization of the Wilson disease gene product (ATP7B) and green fluorescent protein (GFP)-tagged ATP7B in a human hepatoma cell line (Huh7). The intracellular organelles were visualized by fluorescence microscopy. GFP-ATP7B colocalized with late endosome markers, but not with endoplasmic reticulum, Golgi, or lysosome markers in both the steady and copper-loaded states. ATP7B mainly localized at the perinuclear regions in both states. These results suggest that the main localization of ATP7B is in the late endosomes in both the steady and copper-loaded states. ATP7B seems to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes.
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Affiliation(s)
- M Harada
- Second Department of Medicine, Kurume University School of Medicine, Kurume, Japan.
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47
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Abstract
Menkes disease is an X-linked, recessive disorder of copper metabolism that occurs in approximately 1 in 200,000 live births. The condition is characterized by skeletal abnormalities, severe mental retardation, neurologic degeneration, and patient mortality in early childhood. The symptoms of Menkes disease result from a deficiency of serum copper and copper-dependent enzymes. A candidate gene for the disease has been isolated and designated MNK. The MNK gene codes for a P-type cation transporting ATPase, based on homology to known P-type ATPases and in vitro experimentation. cDNA clones of MNK in Menkes patients show diminished or absented hybridization in northern blot experiments. The Menkes protein functions to export excess intracellular copper and activates upon Cu(I) binding to the six metal-binding repeats in the amino-terminal domain. The loss of Menkes protein activity blocks the export of dietary copper from the gastrointestinal tract and causes the copper deficiency associated with Menkes disease. Each of the Menkes protein amino-terminal repeats contains a conserved -X-Met-X-Cys-X-X-Cys- motif (where X is any amino acid). These metal-binding repeats are conserved in other cation exporting ATPases involved in metal metabolism and in proteins involved in cellular defense against heavy metals in both prokaryotes and eukaryotes. An overview of copper metabolism in humans and a discussion of our understanding of the molecular basis of cellular copper homeostasis is presented. This forms the basis for a discussion of Menkes disease and the protein deficit in this disease.
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Affiliation(s)
- M D Harrison
- National Research Centre for Environmental Toxicology, The University of Queensland, Coopers Plains, Australia.
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48
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Gu M, Cooper JM, Butler P, Walker AP, Mistry PK, Dooley JS, Schapira AH. Oxidative-phosphorylation defects in liver of patients with Wilson's disease. Lancet 2000; 356:469-74. [PMID: 10981891 DOI: 10.1016/s0140-6736(00)02556-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Wilson's disease (WD) is caused by mutations in a P-type ATPase and is associated with copper deposition in liver and brain. The WD protein is present in the trans-Golgi network and may also be imported into mitochondria. The WD protein functions as a P-type copper transporting ATPase in the Golgi but any action in mitochondria is at present unknown. METHODS We studied mitochondrial function and aconitase activity in WD liver tissue and compared the results with those in a series of healthy controls and patients without WD. FINDINGS There was evidence of severe mitochondrial dysfunction in the livers of patients with WD. Enzyme activities were decreased as follows: complex I by 62%, complex II+III by 52%, complex IV by 33%, and aconitase by 71%. These defects did not seem to be secondary to penicillamine use, cholestasis, or poor hepatocellular synthetic function. INTERPRETATION The results show that there is a defect of energy metabolism in WD. The pattern of enzyme defects suggests that free-radical formation and oxidative damage, probably mediated via mitochondrial copper accumulation, are important in WD pathogenesis. These results provide a rationale for a study of the use of antioxidants in WD.
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Affiliation(s)
- M Gu
- University Department of Clinical Neurosciences, Royal Free and University College Medical School, and Institute of Neurology, London, UK
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49
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Aston NS, Watt N, Morton IE, Tanner MS, Evans GS. Copper toxicity affects proliferation and viability of human hepatoma cells (HepG2 line). Hum Exp Toxicol 2000; 19:367-76. [PMID: 10962511 DOI: 10.1191/096032700678815963] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In Wilson's disease and Indian childhood cirrhosis (ICC) copper accumulates in the liver resulting in poor hepatocyte regeneration and fibrosis. An inhibition of hepatocyte proliferation and an increase in cell death could account for these outcomes. To establish how the toxicity of this metal ion impacts upon the proliferation and viability of the HepG2 cells they were cultured in 4-32 microM copper(II) sulphate (CuSO4)). These levels were comparable to the circulatory and tissue concentrations of copper recorded for these two diseases. Specific uptake comparable to levels of copper recorded in the livers of patients with Wilson's disease and ICC was measured in the HepG2 cells. After 48 h acid vesicle function increased from 4 to 32 microM Cu2+ but significantly declined at 64 microM compared to the controls. Lysosomal acid phosphatase showed a concentration dependent decline in activity at 72 h. Cellls exposed to 64 microM Cu2+ had a potential doubling time (Tpot) 21 h longer than the control cells due to a prolonged DNA synthesis phase. At 64 microM Cu2+, increases of necrosis up to 18% were seen whereas comparable levels of apoptotic and necrotic cells (<5%) were seen below this concentration. Chronic exposure over 8 weeks impaired colony-forming efficiency at concentrations of 16 microM Cu2+ and above. This study suggests that when liver cells sequester large amounts of copper, the toxic effects include delayed cell-cycle progression, a gradual loss of replicative capacity, and an increased incidence of cell death.
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Affiliation(s)
- N S Aston
- University Division of Child Health, Stephenson Unit, The Children's Hospital, Sheffield, S10 2TH, UK
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50
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Harada M, Sakisaka S, Terada K, Kimura R, Kawaguchi T, Koga H, Taniguchi E, Sasatomi K, Miura N, Suganuma T, Fujita H, Furuta K, Tanikawa K, Sugiyama T, Sata M. Role of ATP7B in biliary copper excretion in a human hepatoma cell line and normal rat hepatocytes. Gastroenterology 2000; 118:921-8. [PMID: 10784591 DOI: 10.1016/s0016-5085(00)70178-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Wilson's disease is a genetic disorder characterized by the accumulation of copper in the body caused by a defect of biliary copper excretion. The Wilson's disease gene has been cloned; however, the precise localization of the gene product (ATP7B) and its role in biliary copper excretion have not been clarified. METHODS We constructed a chimeric protein between green fluorescent protein (GFP) and ATP7B (GFP-ATP7B) and expressed it in a human hepatoma cell line (Huh7) and isolated rat hepatocytes. The Golgi apparatus, late endosomes, lysosomes, and bile canaliculus were visualized by fluorescence microscopy. Brefeldin A and nocodazole were used to redistribute the Golgi proteins. Bafilomycin A1 was used to analyze the association between GFP-ATP7B and the late endosomes. RESULTS GFP-ATP7B colocalized with rhodamine-dextran and late endosome markers but not with the Golgi markers, lysosome markers, or a tight junction protein. Brefeldin A and nocodazole redistributed the Golgi proteins, but they did not affect the distribution of ATP7B. CONCLUSIONS Although it is widely believed that ATP7B is located at the Golgi apparatus, its main localization is in late endosomes. ATP7B seems to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes.
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Affiliation(s)
- M Harada
- Second Department of Medicine, Kurume University School of Medicine, Kurume, Japan
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