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Cañadas-Garre M, Baños-Jaime B, Maqueda JJ, Smyth LJ, Cappa R, Skelly R, Hill C, Brennan EP, Doyle R, Godson C, Maxwell AP, McKnight AJ. Genetic variants affecting mitochondrial function provide further insights for kidney disease. BMC Genomics 2024; 25:576. [PMID: 38858654 PMCID: PMC11163707 DOI: 10.1186/s12864-024-10449-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 05/24/2024] [Indexed: 06/12/2024] Open
Abstract
BACKGROUND Chronic kidney disease (CKD) is a complex disorder that has become a high prevalence global health problem, with diabetes being its predominant pathophysiologic driver. Autosomal genetic variation only explains some of the predisposition to kidney disease. Variations in the mitochondrial genome (mtDNA) and nuclear-encoded mitochondrial genes (NEMG) are implicated in susceptibility to kidney disease and CKD progression, but they have not been thoroughly explored. Our aim was to investigate the association of variation in both mtDNA and NEMG with CKD (and related traits), with a particular focus on diabetes. METHODS We used the UK Biobank (UKB) and UK-ROI, an independent collection of individuals with type 1 diabetes mellitus (T1DM) patients. RESULTS Fourteen mitochondrial variants were associated with estimated glomerular filtration rate (eGFR) in UKB. Mitochondrial variants and haplogroups U, H and J were associated with eGFR and serum variables. Mitochondrial haplogroup H was associated with all the serum variables regardless of the presence of diabetes. Mitochondrial haplogroup X was associated with end-stage kidney disease (ESKD) in UKB. We confirmed the influence of several known NEMG on kidney disease and function and found novel associations for SLC39A13, CFL1, ACP2 or ATP5G1 with serum variables and kidney damage, and for SLC4A1, NUP210 and MYH14 with ESKD. The G allele of TBC1D32-rs113987180 was associated with higher risk of ESKD in patients with diabetes (OR:9.879; CI95%:4.440-21.980; P = 2.0E-08). In UK-ROI, AGXT2-rs71615838 and SURF1-rs183853102 were associated with diabetic nephropathies, and TFB1M-rs869120 with eGFR. CONCLUSIONS We identified novel variants both in mtDNA and NEMG which may explain some of the missing heritability for CKD and kidney phenotypes. We confirmed the role of MT-ND5 and mitochondrial haplogroup H on renal disease (serum variables), and identified the MT-ND5-rs41535848G variant, along with mitochondrial haplogroup X, associated with higher risk of ESKD. Despite most of the associations were independent of diabetes, we also showed potential roles for NEMG in T1DM.
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Affiliation(s)
- Marisa Cañadas-Garre
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK.
- Genomic Oncology Area, Centre for Genomics and Oncological Research: Pfizer, GENYO, University of Granada-Andalusian Regional Government, PTS Granada. Avenida de La Ilustración 114, 18016, Granada, Spain.
- Hematology Department, Hospital Universitario Virgen de Las Nieves, Avenida de Las Fuerzas Armadas 2, 18014, Granada, Spain.
- Instituto de Investigación Biosanitaria de Granada (Ibs.GRANADA), Avda. de Madrid, 15, 18012, Granada, Spain.
| | - Blanca Baños-Jaime
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de La Cartuja (cicCartuja), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Seville, Spain
| | - Joaquín J Maqueda
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
- Experimental Oncology Laboratory, IRCCS Rizzoli Orthopaedic Institute, 40136, Bologna, Italy
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, 40126, Bologna, Italy
| | - Laura J Smyth
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
| | - Ruaidhri Cappa
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
| | - Ryan Skelly
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
| | - Claire Hill
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
| | - Eoin P Brennan
- UCD Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, D04 V1W8, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Ross Doyle
- UCD Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, D04 V1W8, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
- Mater Misericordiae University Hospital, Eccles St, Dublin, D07 R2WY, Ireland
| | - Catherine Godson
- UCD Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, D04 V1W8, Ireland
- School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Alexander P Maxwell
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
- Regional Nephrology Unit, Belfast City Hospital, Level 11Lisburn Road, Belfast, BT9 7AB, UK
| | - Amy Jayne McKnight
- Molecular Epidemiology and Public Health Research Group, Centre for Public Health,, Queen's University Belfast, Institute for Clinical Sciences A, Royal Victoria Hospital, Belfast, BT12 6BA, UK
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Willekens J, Runnels LW. Impact of Zinc Transport Mechanisms on Embryonic and Brain Development. Nutrients 2022; 14:nu14122526. [PMID: 35745255 PMCID: PMC9231024 DOI: 10.3390/nu14122526] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/09/2022] [Accepted: 06/09/2022] [Indexed: 12/04/2022] Open
Abstract
The trace element zinc (Zn) binds to over ten percent of proteins in eukaryotic cells. Zn flexible chemistry allows it to regulate the activity of hundreds of enzymes and influence scores of metabolic processes in cells throughout the body. Deficiency of Zn in humans has a profound effect on development and in adults later in life, particularly in the brain, where Zn deficiency is linked to several neurological disorders. In this review, we will summarize the importance of Zn during development through a description of the outcomes of both genetic and early dietary Zn deficiency, focusing on the pathological consequences on the whole body and brain. The epidemiology and the symptomology of Zn deficiency in humans will be described, including the most studied inherited Zn deficiency disease, Acrodermatitis enteropathica. In addition, we will give an overview of the different forms and animal models of Zn deficiency, as well as the 24 Zn transporters, distributed into two families: the ZIPs and the ZnTs, which control the balance of Zn throughout the body. Lastly, we will describe the TRPM7 ion channel, which was recently shown to contribute to intestinal Zn absorption and has its own significant impact on early embryonic development.
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Biochemical Studies in Perfundates and Homogenates of Isolated Porcine Kidneys after Flushing with Zinc or Zinc-Prolactin Modified Preservation Solution Using a Static Cold Storage Technique. Molecules 2021; 26:molecules26113465. [PMID: 34200394 PMCID: PMC8200954 DOI: 10.3390/molecules26113465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 12/22/2022] Open
Abstract
Zinc is an effective anti-inflammatory and antioxidant trace element. The aim of this study was to analyse the protective effect of zinc and zinc–prolactin systems as additives of preservation solutions in the prevention of nephron damage caused during ischemia. The study used a model for storing isolated porcine kidneys in Biolasol®. The solution was modified with the addition of Zn at a dose of 1 µg/L and Zn: 1 µg/L with prolactin (PRL): 0.1 µg/L. After 2 h and 48 h of storage, the levels of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, sodium, potassium, creatinine and total protein were determined. Zinc added to the Biolasol® composition at a dose of 1 µg/L showed minor effectiveness in the protection of nephrons. In turn, Zn2+ added to Biolasol + PRL (PRL: 0.1 µg/L) acted as a prolactin inhibitor. We do not recommend the addition of Zn(II) (1 µg/L) and Zn(II) (1 µg/L) + PRL (0.1 µg/L) to the Biolasol solution.
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Guantario B, Capolupo A, Monti MC, Leoni G, Ranaldi G, Tosco A, Marzullo L, Murgia C, Perozzi G. Proteomic Analysis of Zn Depletion/Repletion in the Hormone-Secreting Thyroid Follicular Cell Line FRTL-5. Nutrients 2018; 10:nu10121981. [PMID: 30558183 PMCID: PMC6315927 DOI: 10.3390/nu10121981] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
Zinc deficiency predisposes to a wide spectrum of chronic diseases. The human Zn proteome was predicted to represent about 10% of the total human proteome, reflecting the broad array of metabolic functions in which this micronutrient is known to participate. In the thyroid, Zn was reported to regulate cellular homeostasis, with a yet elusive mechanism. The Fischer Rat Thyroid Cell Line FRTL-5 cell model, derived from a Fischer rat thyroid and displaying a follicular cell phenotype, was used to investigate a possible causal relationship between intracellular Zn levels and thyroid function. A proteomic approach was applied to compare proteins expressed in Zn deficiency, obtained by treating cells with the Zn-specific chelator N,N,N′,N′-tetrakis (2-pyridylmethyl) ethylene-diamine (TPEN), with Zn repleted cells. Quantitative proteomic analysis of whole cell protein extracts was performed using stable isotope dimethyl labelling coupled to nano-ultra performance liquid chromatography-mass spectrometry (UPLC-MS). TPEN treatment led to almost undetectable intracellular Zn, while decreasing thyroglobulin secretion. Subsequent addition of ZnSO4 fully reversed these phenotypes. Comparative proteomic analysis of Zn depleted/repleted cells identified 108 proteins modulated by either treatment. Biological process enrichment analysis identified functions involved in calcium release and the regulation of translation as the most strongly regulated processes in Zn depleted cells.
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Affiliation(s)
- Barbara Guantario
- Research Centre for Food and Nutrition, CREA, Via Ardeatina 546, 00178 Rome, Italy.
| | - Angela Capolupo
- Department of Pharmacy, Division of Chemistry & Chemical Technologies "Luigi Gomez Paloma", University of Salerno, Via Giovanni Paolo II, 132 84084 Fisciano (SA), Italy.
| | - Maria Chiara Monti
- Department of Pharmacy, Division of Chemistry & Chemical Technologies "Luigi Gomez Paloma", University of Salerno, Via Giovanni Paolo II, 132 84084 Fisciano (SA), Italy.
| | - Guido Leoni
- Nouscom, via di Castel Romano 100, 00128 Rome, Italy.
| | - Giulia Ranaldi
- Research Centre for Food and Nutrition, CREA, Via Ardeatina 546, 00178 Rome, Italy.
| | - Alessandra Tosco
- Department of Pharmacy Biomedical Division "Arturo Leone", University of Salerno, Via Giovanni Paolo II, 132 84084 Fisciano (SA), Italy.
| | - Liberato Marzullo
- Department of Medicine, Surgery and Dentistry "Schola Medica Salernitana", University of Salerno, Via Salvador Allende, 84081 Baronissi (SA), Italy.
| | - Chiara Murgia
- Department of Nutrition, Dietetics and Food, Monash University, Melbourne, VIC 3168, Australia.
| | - Giuditta Perozzi
- Research Centre for Food and Nutrition, CREA, Via Ardeatina 546, 00178 Rome, Italy.
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El-Safty I, Eltamany E, Shouman A, El-Gamel O, Nada A, Ali W. Effect of tramadol addiction alone and its co-abuse with cannabis on urinary excretion of Copper, Zinc, and Calcium among Egyptian addicts. Afr Health Sci 2018; 18:767-775. [PMID: 30603010 PMCID: PMC6307004 DOI: 10.4314/ahs.v18i3.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The use of illicit drugs has become a worldwide health problem. Substances with the potential to be abused may have direct or indirect effects on physiologic mechanisms that lead to organ system dysfunction and diseases. OBJECTIVE The present study aims to investigate the structural and reabsorption integrity of the nephron among Egyptian addicts of tramadol alone and coabused with cannabis. METHODS Sixty-five males were included in the study, they were classified into control group (G1=19), tramadol addicts group (G2=18), and tramadol coabused with cannabis addicts group (G3=28). Parameters investigated for structural integrity were urinary levels ofleucineaminopeptidase and N-acetyl-β-D-glucosaminidase, and urinary parameters for reabsorption integrity were levels of copper and zinc as well as calcium, also urinary creatinine was measured. In addition, urinary levels of tramadol and tetrahydrocannabinol were estimated. RESULTS Among the two addicted groups, all measured parameters were not significantly different in comparison with the control group except for urinary calcium excretion which was found to be significantly increased among the two addicted groups. CONCLUSION Both tramadol addiction alone or coabused with cannabis causes increased urinary excretion of calcium, indicating reabsorption dysfunction of calcium without affecting structural integrity along the nephron.
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Affiliation(s)
- Ibrahim El-Safty
- Chemistry Department, Faculty of Education, Ain-Shams University, Heliopolis, Roxy, Cairo, Egypt
| | - Elsayed Eltamany
- Chemistry Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Ahmed Shouman
- Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain-Shams University, Cairo, Egypt
| | - Omayma El-Gamel
- Clinical Pathology Department, El-Demerdash Hospital, Faculty of Medicine, Ain-Shams University, Cairo, Egypt
| | - Ahmed Nada
- Atomic Energy Authority, Nasr City, Cairo, Egypt
| | - Wesam Ali
- Chemistry Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
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Bafaro E, Liu Y, Xu Y, Dempski RE. The emerging role of zinc transporters in cellular homeostasis and cancer. Signal Transduct Target Ther 2017; 2:17029. [PMID: 29218234 PMCID: PMC5661630 DOI: 10.1038/sigtrans.2017.29] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/21/2017] [Accepted: 04/25/2017] [Indexed: 12/21/2022] Open
Abstract
Zinc is an essential micronutrient that plays a role in the structural or enzymatic functions of many cellular proteins. Cellular zinc homeostasis involves the opposing action of two families of metal transporters: the ZnT (SLC30) family that functions to reduce cytoplasmic zinc concentrations and the ZIP (SLC39) family that functions to increase cytoplasmic zinc concentrations. Fluctuations in intracellular zinc levels mediated by these transporter families affect signaling pathways involved in normal cell development, growth, differentiation and death. Consequently, changes in zinc transporter localization and function resulting in zinc dyshomeostasis have pathophysiological effects. Zinc dyshomeostasis has been implicated in the progression of cancer. Here we review recent progress toward understanding the structural basis for zinc transport by ZnT and ZIP family proteins, as well as highlight the roles of zinc as a signaling molecule in physiological conditions and in various cancers. As zinc is emerging as an important signaling molecule in the development and progression of cancer, the ZnT and ZIP transporters that regulate cellular zinc homeostasis are promising candidates for targeted cancer therapy.
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Affiliation(s)
- Elizabeth Bafaro
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Yuting Liu
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Yan Xu
- Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Robert E Dempski
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
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7
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Colvin RA, Jin Q, Lai B, Kiedrowski L. Visualizing Metal Content and Intracellular Distribution in Primary Hippocampal Neurons with Synchrotron X-Ray Fluorescence. PLoS One 2016; 11:e0159582. [PMID: 27434052 PMCID: PMC4951041 DOI: 10.1371/journal.pone.0159582] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/04/2016] [Indexed: 02/03/2023] Open
Abstract
Increasing evidence suggests that metal dyshomeostasis plays an important role in human neurodegenerative diseases. Although distinctive metal distributions are described for mature hippocampus and cortex, much less is known about metal levels and intracellular distribution in individual hippocampal neuronal somata. To solve this problem, we conducted quantitative metal analyses utilizing synchrotron radiation X-Ray fluorescence on frozen hydrated primary cultured neurons derived from rat embryonic cortex (CTX) and two regions of the hippocampus: dentate gyrus (DG) and CA1. Comparing average metal contents showed that the most abundant metals were calcium, iron, and zinc, whereas metals such as copper and manganese were less than 10% of zinc. Average metal contents were generally similar when compared across neurons cultured from CTX, DG, and CA1, except for manganese that was larger in CA1. However, each metal showed a characteristic spatial distribution in individual neuronal somata. Zinc was uniformly distributed throughout the cytosol, with no evidence for the existence of previously identified zinc-enriched organelles, zincosomes. Calcium showed a peri-nuclear distribution consistent with accumulation in endoplasmic reticulum and/or mitochondria. Iron showed 2-3 distinct highly concentrated puncta only in peri-nuclear locations. Notwithstanding the small sample size, these analyses demonstrate that primary cultured neurons show characteristic metal signatures. The iron puncta probably represent iron-accumulating organelles, siderosomes. Thus, the metal distributions observed in mature brain structures are likely the result of both intrinsic neuronal factors that control cellular metal content and extrinsic factors related to the synaptic organization, function, and contacts formed and maintained in each region.
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Affiliation(s)
- Robert A. Colvin
- Department of Biological Sciences, Interdisciplinary Graduate Program in Molecular and Cellular Biology, Neuroscience Program, Ohio University, Athens, Ohio, United States of America
| | - Qiaoling Jin
- Department of Physics & Astronomy, Northwestern University, Evanston, Illinois, United States of America
| | - Barry Lai
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois, United States of America
| | - Lech Kiedrowski
- The Psychiatric Institute, Departments of Psychiatry and Pharmacology, the University of Illinois at Chicago, Chicago, Illinois, United States of America
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Kambe T, Tsuji T, Hashimoto A, Itsumura N. The Physiological, Biochemical, and Molecular Roles of Zinc Transporters in Zinc Homeostasis and Metabolism. Physiol Rev 2015; 95:749-84. [DOI: 10.1152/physrev.00035.2014] [Citation(s) in RCA: 556] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Zinc is involved in a variety of biological processes, as a structural, catalytic, and intracellular and intercellular signaling component. Thus zinc homeostasis is tightly controlled at the whole body, tissue, cellular, and subcellular levels by a number of proteins, with zinc transporters being particularly important. In metazoan, two zinc transporter families, Zn transporters (ZnT) and Zrt-, Irt-related proteins (ZIP) function in zinc mobilization of influx, efflux, and compartmentalization/sequestration across biological membranes. During the last two decades, significant progress has been made in understanding the molecular properties, expression, regulation, and cellular and physiological roles of ZnT and ZIP transporters, which underpin the multifarious functions of zinc. Moreover, growing evidence indicates that malfunctioning zinc homeostasis due to zinc transporter dysfunction results in the onset and progression of a variety of diseases. This review summarizes current progress in our understanding of each ZnT and ZIP transporter from the perspective of zinc physiology and pathogenesis, discussing challenging issues in their structure and zinc transport mechanisms.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tokuji Tsuji
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Ayako Hashimoto
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Naoya Itsumura
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Haller-Kikkatalo K, Pruul K, Kisand K, Nemvalts V, Reimand K, Uibo R. GADA and anti-ZnT8 complicate the outcome of phenotypic type 2 diabetes of adults. Eur J Clin Invest 2015; 45:255-62. [PMID: 25611374 DOI: 10.1111/eci.12404] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/17/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND A proportion of phenotypic type 2 diabetes (T2D) patients produce pancreatic autoantibodies and a majority of T2D patients develop serious life-disabling complications over time despite the implementation of adequate clinical interventions. This study determined whether the presence of pancreatic autoantibodies (GADA, IA-2A, anti-ZnT8, or ICA) was associated with serious complications or concomitant diseases of adult patients diagnosed with T2D (N = 305). MAIN RESULTS In the study population, 22.3% (N = 68) of subjects were positive for at least 1 of the 4 of the markers associated with autoimmune diabetes (presence of pancreatic autoantibody - pAb), followed by GADA (14.1%, N = 43), ICA (8.9%, N = 27), anti-ZnT8 (5.6%, N = 17) and IA-2A (2.0%, N = 6). Logistic regression analysis adjusted for patient's age, gender and duration of T2D revealed that (i) pAb was associated with higher prevalence of adiposity (odds ratio of adjusted regression model (adOR) 2.51, P = 0.032); (ii) pAb, GADA and anti-ZnT8 were associated with autoimmune thyroid disease (adORs 3.07, P = 0.012; 6.29, P < 0.001 and 3.52, P = 0.052, respectively); (iii) pAb and GADA, in particular, were risk factors for neurological complications (adORs 2.10, P = 0.036; 2.76, P = 0.009, respectively) and polyneuropathy in particular (adORs 2.60, P = 0.012; 3.10, P = 0.007, respectively); and (iv) anti-ZnT8 was a risk factor for developing nephropathy (adOR 4.61, P = 0.022). In addition, adiposity was associated with 5.3-year earlier onset of disease (adjusted linear regression model, P = 0.006). CONCLUSIONS These results suggest that GADA and anti-ZnT8 are associated with progression of serious T2D complications, including polyneuropathy and nephropathy. In addition, adiposity represents a significant risk for autoimmunity development in T2D patients.
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Affiliation(s)
- Kadri Haller-Kikkatalo
- Department of Immunology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia; Competence Centre on Health Technologies, Tartu, Estonia; Department of Obstetrics and Gynecology, University of Tartu, Tartu, Estonia
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10
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Markadieu N, Rios K, Spiller BW, McDonald WH, Welling PA, Delpire E. Short forms of Ste20-related proline/alanine-rich kinase (SPAK) in the kidney are created by aspartyl aminopeptidase (Dnpep)-mediated proteolytic cleavage. J Biol Chem 2014; 289:29273-84. [PMID: 25164821 DOI: 10.1074/jbc.m114.604009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Ste20-related kinase SPAK regulates sodium, potassium, and chloride transport in a variety of tissues. Recently, SPAK fragments, which lack the catalytic domain and are inhibitory to Na(+) transporters, have been detected in kidney. It has been hypothesized that the fragments originate from alternative translation start sites, but their precise origin is unknown. Here, we demonstrate that kidney lysate possesses proteolytic cleavage activity toward SPAK. Ion exchange and size exclusion chromatography combined with mass spectrometry identified the protease as aspartyl aminopeptidase. The presence of the protease was verified in the active fractions, and recombinant aspartyl aminopeptidase recapitulated the cleavage pattern observed with kidney lysate. Identification of the sites of cleavage by mass spectrometry allowed us to test the function of the smaller fragments and demonstrate their inhibitory action toward the Na(+)-K(+)-2Cl(-) cotransporter, NKCC2.
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Affiliation(s)
| | | | | | - W Hayes McDonald
- Biochemistry and the Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 and
| | - Paul A Welling
- the Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
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11
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Haase H, Rink L. Zinc signals and immune function. Biofactors 2014; 40:27-40. [PMID: 23804522 DOI: 10.1002/biof.1114] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/23/2013] [Accepted: 04/25/2013] [Indexed: 12/21/2022]
Abstract
For more than 50 years, it has been known that zinc deficiency compromises immune function. During this time, knowledge about the biochemistry of zinc has continued to grow, but only recent years have provided in-depth molecular insights into the multiple aspects of zinc as a regulator of immunity. A network based on ZnT and ZIP proteins for transport and metallothionein for storage tightly regulates zinc availability, and virtually all aspects of innate and adaptive immunity are affected by zinc. In vivo, zinc deficiency alters the number and function of neutrophil granulocytes, monocytes, natural killer (NK)-, T-, and B-cells. T cell functions and balance between the different subsets are particularly susceptible to changes in zinc status. This article focuses in particular on the main mechanisms by which zinc ions exert essential functions in the immune system. On the one hand, this includes tightly protein bound zinc ions serving catalytic or structural functions in a multitude of different proteins, in particular enzymes and transcription factors. On the other hand, increasing evidence arises for a regulatory role of free zinc ions in signal transduction, especially in cells of the immune system. Identification of several molecular targets, including phosphatases, phosphodiesterases, caspases, and kinases suggest that zinc ions are a second messenger regulating signal transduction in various kinds of immune cells.
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Affiliation(s)
- Hajo Haase
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
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12
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Ezaki B, Nakakihara E. Possible involvement of GDI1 protein, a GDP dissociation inhibitor related to vesicle transport, in an amelioration of zinc toxicity in Saccharomyces cerevisiae. Yeast 2011; 29:17-24. [PMID: 22125264 DOI: 10.1002/yea.1913] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 10/14/2011] [Indexed: 11/07/2022] Open
Abstract
The GDI1 protein related vesicle transport system was studied to investigate the possibility that an exclusion of toxic zinc (Zn) from the cytoplasm ameliorates Zn toxicity in Saccharomyces cerevisiae (yeast). A temperature-sensitive gdi1 mutant (originally called sec19), in which the GDP dissociation inhibitor becomes inactive at the non-permissive temperature (37 °C), was more sensitive to Zn than its parental GDI1 strain at 32 °C (a moderately non-permissive temperature). The relative efflux of cytoplasmic Zn in the gdi1 mutant was lower than that in the control strain. Treatment with a vesicle transport-specific inhibitor, Brefeldin A, caused an increase of Zn sensitivity and a decrease of Zn efflux in these strains. It is therefore suggested that the GDI1-related vesicle transport system contributes to Zn tolerance in yeast. Furthermore, changes in the number of Zn-specific fluorescent granules (zincosomes) were observed by zinquin staining in the mutant cells under Zn treatment at 32 °C and 37 °C. We concluded that the GDI1 protein is implicated in control of vesicle numbers. Collectively, the results suggest that the GDI1protein is involved in Zn efflux via small vesicle trafficking and contributes to the control of cytoplasmic Zn content, allowing yeast to survive in the presence of toxic Zn.
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Affiliation(s)
- Bunichi Ezaki
- Institute of Plant Science and Resources, Okayama University, Japan.
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13
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Fukunaka A, Kurokawa Y, Teranishi F, Sekler I, Oda K, Ackland ML, Faundez V, Hiromura M, Masuda S, Nagao M, Enomoto S, Kambe T. Tissue nonspecific alkaline phosphatase is activated via a two-step mechanism by zinc transport complexes in the early secretory pathway. J Biol Chem 2011; 286:16363-73. [PMID: 21402707 DOI: 10.1074/jbc.m111.227173] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A number of enzymes become functional by binding to zinc during their journey through the early secretory pathway. The zinc transporters (ZnTs) located there play important roles in this step. We have previously shown that two zinc transport complexes, ZnT5/ZnT6 heterodimers and ZnT7 homo-oligomers, are required for the activation of alkaline phosphatases, by converting them from the apo- to the holo-form. Here, we investigated the molecular mechanisms of this activation. ZnT1 and ZnT4 expressed in chicken DT40 cells did not contribute to the activation of tissue nonspecific alkaline phosphatase (TNAP). The reduced activity of TNAP in DT40 cells deficient in both ZnT complexes was not restored by zinc supplementation nor by exogenous expression of other ZnTs that increase the zinc content in the secretory pathway. Moreover, we showed that expression of ZnT5/ZnT6 heterodimers reconstituted with zinc transport-incompetent ZnT5 mutant failed to restore TNAP activity but could stabilize the TNAP protein as the apo-form, regardless of zinc status. These findings demonstrate that TNAP is activated not simply by passive zinc binding but by an elaborate two-step mechanism via protein stabilization followed by enzyme conversion from the apo- to the holo-form with zinc loaded by ZnT complexes in the early secretory pathway.
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Affiliation(s)
- Ayako Fukunaka
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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14
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Guo L, Hu X, Xu T, Qi X, Wan Y, Liu X, Jiang Y, Zhang L. Over-expression of Zip-13 mRNA in kidney and lung during dietary zinc deficiency in Wistar rats. Mol Biol Rep 2010; 38:1869-74. [PMID: 20859692 DOI: 10.1007/s11033-010-0304-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 09/03/2010] [Indexed: 10/19/2022]
Abstract
Zinc is an essential nutrient for all organisms, which is involved in the function of numerous key enzymes in metabolism. Two gene families have been identified involved in zinc homeostasis. ZnT transporters reduce intracellular zinc while Zip transporters increase intracellular zinc. Previous studies in our laboratory have shown that Zip-1, ZnT-1, Zip-2 and LIV-1 mRNA are associated with zinc level in established human breast cancer in nude mice model. In this study, six zinc transporters: ZnT-1, ZnT-2, ZnT-4, Zip-1, Zip-8 and Zip-13 were chosen. We aim to determine the relation between zinc transporters and zinc level in kidney and lung of Wistar rats. Eighteen Wistar rats were randomly divided into three groups: normal group, zinc-deficiency group and pair-fed group. After 22 days, the rats were killed and organs samples were taken, then zinc transporters mRNA were detected by RT-PCR. Compared with the normal group, Zip-13 shows an up-regulation (P < 0.05) in zinc-deficiency group both in kidney and lung, and Zip-8 was significantly lower (P < 0.05) in zinc-deficiency group in kidney.
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Affiliation(s)
- Lu Guo
- Institute of Biochemistry and Molecular Biology, Shandong University School of Medicine, 44# Wenhua Xi Road, Jinan, 250012 Shandong, People's Republic of China
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15
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Falcón-Pérez JM, Dell'Angelica EC. Zinc transporter 2 (SLC30A2) can suppress the vesicular zinc defect of adaptor protein 3-depleted fibroblasts by promoting zinc accumulation in lysosomes. Exp Cell Res 2007; 313:1473-83. [PMID: 17349999 PMCID: PMC1885236 DOI: 10.1016/j.yexcr.2007.02.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 01/26/2007] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
Zinc accumulation in the lumen of cytoplasmic vesicles is one of the mechanisms by which cells can store significant amounts of this essential but potentially toxic biometal. Previous studies had demonstrated reduced vesicular zinc levels in fibroblasts from mutant mice deficient in adaptor protein 3 (AP-3), a complex involved in protein trafficking to late endosomes and lysosomes. We have observed a similar phenotype in the human fibroblastoid cell line, M1, upon small interference RNA-mediated AP-3 knockdown. A survey of the expression and localization of zinc transporter (ZnT) family members identified ZnT2, ZnT3, and ZnT4 as likely mediators of vesicular zinc accumulation in M1 cells. Expression of green fluorescence protein (GFP)-tagged ZnT2 and ZnT3 promoted accumulation of vesicular zinc as visualized using the indicator zinquin. Moreover, GFP-ZnT2 overexpression elicited a significant accumulation of zinc within mature lysosomes, which in untransfected M1 cells contained little or no chelatable zinc, and restored the zinc storage capability of AP-3-deficient cells. These results suggest that ZnT2 can facilitate vesicular zinc accumulation independently of AP-3 function, and validate the M1 fibroblastoid line as a human cell culture system amenable to the study of vesicular zinc regulation using techniques compatible with functional genomic approaches.
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Affiliation(s)
- Juan M Falcón-Pérez
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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16
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Danscher G, Stoltenberg M. Silver enhancement of quantum dots resulting from (1) metabolism of toxic metals in animals and humans, (2) in vivo, in vitro and immersion created zinc–sulphur/zinc–selenium nanocrystals, (3) metal ions liberated from metal implants and particles. ACTA ACUST UNITED AC 2006; 41:57-139. [PMID: 16949439 DOI: 10.1016/j.proghi.2006.06.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Autometallographic (AMG) silver enhancement is a potent histochemical tool for tracing a variety of metal containing nanocrystals, e.g. pure gold and silver nanoclusters and quantum dots of silver, mercury, bismuth or zinc, with sulphur and/or selenium. These nanocrystals can be created in many different ways, e.g. (1) by manufacturing colloidal gold or silver particles, (2) by treating an organism in vivo with sulphide or selenide ions, (3) as the result of a metabolic decomposition of bismuth-, mercury- or silver-containing macromolecules in cell organelles, or (4) as the end product of histochemical processing of tissue sections. Such nano-sized AMG nanocrystals can then be silver-amplified several times of magnitude by being exposed to an AMG developer, i.e. a normal photographic developer enriched with silver ions. The present monograph attempts to provide a review of the autometallographic silver amplification techniques known today and their use in biology. After achieving a stronghold in histochemistry by Timm's introduction of the "silver-sulphide staining" in 1958, the AMG technique has evolved and expanded into several different areas of research, including immunocytochemistry, tracing of enzymes at LM and EM levels, blot staining, retrograde axonal tracing of zinc-enriched (ZEN) neurons, counterstaining of semithin sections, enhancement of histochemical reaction products, marking of phagocytotic cells, staining of myelin, tracing of gold ions released from gold implants, and visualization of capillaries. General technical comments, protocols for the current AMG methods and a summary of the most significant scientific results obtained by this wide variety of AMG histochemical approaches are included in the present article.
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Affiliation(s)
- Gorm Danscher
- Department of Neurobiology, Institute of Anatomy, University of Aarhus, DK-8000 Aarhus C, Denmark.
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17
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Colvin RA, Laskowski M, Fontaine CP. Zinquin identifies subcellular compartmentalization of zinc in cortical neurons. Relation to the trafficking of zinc and the mitochondrial compartment. Brain Res 2006; 1085:1-10. [PMID: 16581038 DOI: 10.1016/j.brainres.2006.02.043] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 01/31/2006] [Accepted: 02/07/2006] [Indexed: 11/20/2022]
Abstract
Zinquin (Zn(2+) selective fluorophore), when used to visualize intracellular Zn(2+), typically shows brightly fluorescent perinuclear endosome-like structures, presumably identifying Zn(2+) containing organelles. In this study, zinquin identified numerous and widespread sites of Zn(2+) compartmentalization in primary cultures of embryonic rat cortical neurons. Nuclear fluorescence, however, was absent. We labeled neuronal mitochondria with MitoTracker Green in the presence of zinquin and show that the fluorescent patterns of MitoTracker Green and zinquin were distinct and clearly different in both the perinuclear region and in processes. The mitochondrial compartment was much larger than the sum of the areas of zinquin fluorescence, as indicated by the small amount (<10% MitoTracker Green over zinquin) of overlap of MitoTracker Green on zinquin. Zinquin fluorescence was unaffected by carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) treatment. The zinquin fluorescent objects were generally spherical in shape with a average diameter of about 0.6 mum. Most fluorescent objects, nearly two thirds on average, appeared to be docked, but both anterograde and retrograde movements were observed by time lapse image analysis. Although some fluorescent objects moved as much as 1 mum in 5 min, typical movements were smaller, usually 0.5 mum or less. Colchicine treatment caused striking aggregation of MitoTracker Green most noticeable in the perinuclear region. Zinquin fluorescence similarly showed reduced distribution throughout the cytoplasm, suggesting that zinquin fluorescent structures were associated with microtubules. Treatment with cytochalasin D had little noticeable effect on either the pattern of zinquin and MitoTracker Green fluorescence or their coincidence. Thus, numerous Zn(2+) sequestering organelles/structures are present in perinuclear regions and processes of cultured neurons and are sometimes found coincident with mitochondria. We demonstrated real time trafficking of sequestered Zn(2+), using zinquin fluorescence, apparently associated with an endosome-like compartment or protein complexes in the cytosol.
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Affiliation(s)
- Robert A Colvin
- Department of Biological Sciences, Program in Neuroscience, Ohio University, Athens, OH 45701, USA.
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18
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Murgia C, Vespignani I, Rami R, Perozzi G. The Znt4 mutation inlethal milk mice affects intestinal zinc homeostasis through the expression of other Zn transporters. GENES & NUTRITION 2006; 1:61-70. [PMID: 18850221 PMCID: PMC3454819 DOI: 10.1007/bf02829937] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 03/30/2006] [Indexed: 10/22/2022]
Abstract
The lethal milk mouse syndrome is caused by a point mutation in the zinc transporter gene ZnT4 resulting in defective zinc secretion in the milk of homozygous mutant dams. Pups of any genotype fed solely on lm milk die within the first two weeks of neonatal life, displaying zinc deficiency symptoms. Homozygous mutant pups survive when foster nursed by wild type dams and show signs of mild zinc deficiency in adulthood. To further investigate the role of ZnT4 in zinc secretion in the intestinal epithelium, we have studied the expression by real time quantitative PCR of mutant ZnT4 and of other zinc transporters of the Zip and ZnT families, in the jejunum of homozygous lm mice and of the isogenic wild type strain C57BL/ 6J. We report in this paper that expression of the mutant ZnT4 mRNA, carrying a premature translational termination codon (ZnT4/lm), is almost absent in tissues from lm mice, probably as a result of degradation by the Nonsense Mediated mRNA Decay (NMD) Pathway. In the jejunum of mutant mice, we also observed decreased expression of the uptake zinc transporter Zip4, paralleled by increased levels of both metallothionein genes MTI and MTII. Zinc supplementation of lm mice in the drinking water did not result in further decrease of Zip4 expression, but led to full induction of MT mRNAs. These results lead us to conclude that, although in the enterocytes of lm mice the absence of the zinc secretion activity mediated by ZnT4 results in increased intracellular zinc concentration, other zinc efflux activities are able to maintain the level of zinc ions below the threshold necessary for full induction of metallothioneins.
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Affiliation(s)
- Chiara Murgia
- INRAN, National Research Institute on Food and Nutrition, via Ardeatina 546, 00178 Roma, Italy
| | - Isabella Vespignani
- INRAN, National Research Institute on Food and Nutrition, via Ardeatina 546, 00178 Roma, Italy
| | - Rita Rami
- INRAN, National Research Institute on Food and Nutrition, via Ardeatina 546, 00178 Roma, Italy
| | - Giuditta Perozzi
- INRAN, National Research Institute on Food and Nutrition, via Ardeatina 546, 00178 Roma, Italy
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19
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Wang ZY, Stoltenberg M, Huang L, Danscher G, Dahlström A, Shi Y, Li JY. Abundant expression of zinc transporters in Bergman glia of mouse cerebellum. Brain Res Bull 2005; 64:441-8. [PMID: 15607832 DOI: 10.1016/j.brainresbull.2004.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 09/28/2004] [Accepted: 10/05/2004] [Indexed: 11/20/2022]
Abstract
Zinc transporters (ZnTs) are membrane proteins involved in zinc ion transportation in mammalian cells. Seven members of ZnT family, ZnT1-7, have been cloned and characterized. These transporter proteins have different cellular and sub-cellular locations, suggesting that they may play different roles in zinc homeostasis in normal and pathological conditions in different tissues. Cerebellum is one of the most zinc-enriched regions in the central nervous system, but little is known about zinc metabolism in the cerebellum. In the present study, we investigated the detailed distributions of four members (ZnT1, ZnT3, ZnT4 and ZnT6) of the ZnT family, in the mouse cerebellum. Immunostaining and confocal microscopic observations revealed a similar staining pattern of ZnTs in the molecular layer and the Purkinje cell layer. Double labeling with anti-S-100beta or anti-MAP2 and anti-ZnTs clearly showed that the Bergman glial cell bodies in the Purkinje cell layer and their radial processes in the molecular layer exhibited strong immunofluorescence of all the tested ZnTs. However, the somata of the Purkinje cells contained a moderate immunostaining for ZnT1, but virtually lack of other three ZnTs. In the granular layer, ZnTs appeared with different immunostaining patterns. ZnT1 was expressed in a small number of neuronal cell bodies and their primary dendrites, whereas ZnT3 and ZnT4 were present in nerve terminals but not in the neuronal somata. ZnT6 was undetectable in either the cell bodies or processes in the granular layer. The present results indicate that the Bergman glial cells may play an important role in zinc metabolism in the mouse cerebellar cortex.
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Affiliation(s)
- Zhan-You Wang
- Department of Histology and Embryology, China Medical University, 92 Bei-Er-Road, Heping District, Shenyang 110001, PR China.
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20
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Zalewski PD, Truong-Tran AQ, Grosser D, Jayaram L, Murgia C, Ruffin RE. Zinc metabolism in airway epithelium and airway inflammation: basic mechanisms and clinical targets. A review. Pharmacol Ther 2004; 105:127-49. [PMID: 15670623 DOI: 10.1016/j.pharmthera.2004.09.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2004] [Indexed: 12/22/2022]
Abstract
In addition to basic housekeeping roles in metalloenzymes and transcription factors, dietary zinc (Zn) is an important immunoregulatory agent, growth cofactor, and cytoprotectant with anti-oxidant, anti-apoptotic, and anti-inflammatory roles. These properties of Zn are of particular importance in maintaining homeostasis of epithelial tissues which are at the front line of defense. This review is about the role of Zn in airway epithelium (AE). The first part focuses on the cellular biology of Zn, and what is known about its distribution and function in AE. The second part of the review considers evidence for altered Zn metabolism in asthma and other chronic diseases of airway inflammation. Important issues arise from a potential therapeutic perspective as to the optimal ways to monitor circulating and epithelial Zn levels in patients and the most effective means of supplementing these levels.
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Affiliation(s)
- Peter D Zalewski
- Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital, Woodville, South Australia 5011, Australia.
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21
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Devergnas S, Chimienti F, Naud N, Pennequin A, Coquerel Y, Chantegrel J, Favier A, Seve M. Differential regulation of zinc efflux transporters ZnT-1, ZnT-5 and ZnT-7 gene expression by zinc levels: a real-time RT–PCR study. Biochem Pharmacol 2004; 68:699-709. [PMID: 15276077 DOI: 10.1016/j.bcp.2004.05.024] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Accepted: 05/04/2004] [Indexed: 11/19/2022]
Abstract
Intracellular zinc levels are strictly regulated by zinc channels and zinc-binding proteins to maintain cellular zinc-dependent functions. We demonstrated a correlation between extracellular zinc concentration and intracellular exchangeable zinc levels using the fluorescent zinc-specific probes zinquin and zinpyr-1. The effect of extracellular zinc status on the regulation of the two trans-Golgi network directed zinc transporters ZnT-5 and ZnT-7 was next studied by real-time RT-PCR in zinc supplemented or depleted HeLa cells. While sub-toxic extracellular zinc addition strongly induced the efflux transporter ZnT-1 gene expression, consistent with its activation by the transcription factor MTF-1, treated HeLa cells did not display any change in ZnT-5 and ZnT-7 mRNA levels compared to control cells. In contrast, zinc depletion induced by non-toxic doses of the zinc chelator TPEN (N,N,N',N' tetrakis-(2 pyridylmethyl) ethylene diamine) resulted in a up to eight-fold induction of transporters ZnT-5 and ZnT-7 mRNA levels, providing the first evidence of a transcriptional control of these two zinc efflux transporters by zinc deficiency in cultured cells.
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Affiliation(s)
- Séverine Devergnas
- Laboratoire des lésions des acides nucléiques, DRFMC/SCIB/LAN, CEA/Grenoble, 17 rue des Martyrs, 38000 Grenoble, France
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22
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Zhou X, Vize PD. Proximo-distal specialization of epithelial transport processes within the Xenopus pronephric kidney tubules. Dev Biol 2004; 271:322-38. [PMID: 15223337 DOI: 10.1016/j.ydbio.2004.03.036] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 02/20/2004] [Accepted: 03/22/2004] [Indexed: 11/25/2022]
Abstract
The embryonic kidneys of larval aquatic vertebrates such as fish and frogs serve as excellent model systems for exploring the early development of nephric organs. These experimental systems can easily be manipulated by microsurgery, microinjection, genetics, or combinations of these approaches. However, little is known about how physiologically similar these simple kidneys are to the more complex mammalian adult kidneys. In addition, almost nothing is known about proximo-distal patterning of nephrons in any organism. In order begin to explore the physiological specialization of the pronephric tubules along the proximo-distal axis, a combination of uptake assays using fluorescently tagged proteins, LDL particles and dextrans, and an informatics-targeted in situ screen for transport proteins have been performed on embryos of the frog, Xenopus laevis. Genes identified to be expressed within unique subdomains of the pronephric tubules include an ABC transporter, two amino acid cotransporters, two sodium bicarbonate cotransporters, a novel sodium glucose cotransporter, a sodium potassium chloride cotransporter (NKCC2), a sodium chloride organic solute cotransporter (ROSIT), and a zinc transporter. A novel combination of colorimetric and fluorescent whole-mount in situ hybridization (FCIS) was used to precisely map the expression domain of each gene within the pronephros. These data indicate specialized physiological function and define multiple novel segments of the pronephric tubules, which contain at least six distinct transport domains. Uptake studies identified functional transport domains and also demonstrated that early glomeral leakage can allow visualization of protein movement into the pronephric tubules and thus establish a system for investigating experimentally induced proteinuria and glomerulonephritis.
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Affiliation(s)
- Xiaolan Zhou
- Department of Biological Science, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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23
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Ho LH, Ruffin RE, Murgia C, Li L, Krilis SA, Zalewski PD. Labile Zinc and Zinc Transporter ZnT4in Mast Cell Granules: Role in Regulation of Caspase Activation and NF-κB Translocation. THE JOURNAL OF IMMUNOLOGY 2004; 172:7750-60. [PMID: 15187159 DOI: 10.4049/jimmunol.172.12.7750] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The granules of mast cells and other inflammatory cells are known to be rich in zinc (Zn), a potent caspase inhibitor. The functions of granular Zn, its mechanism of uptake, and its relationship to caspase activation in apoptosis are unclear. The granules of a variety of mast cell types fluoresced intensely with the Zn-specific fluorophore Zinquin, and fluorescence was quenched by functional depletion of Zn using a membrane-permeable Zn chelator N, N, N', N'-tetrakis (2-pyridyl-methyl)ethylenediamine (TPEN). Zn levels were also depleted by various mast cell activators, including IgE/anti-IgE, and Zn was rapidly replenished during subsequent culture, suggesting an active uptake mechanism. In support of the latter, mast cells contained high levels of the vesicular Zn transporter ZnT(4), especially in the more apical granules. Immunofluorescence and immunogold labeling studies revealed significant pools of procaspase-3 and -4 in mast cell granules and their release during degranulation. Functional depletion of Zn by chelation with TPEN, but not by degranulation, resulted in greatly increased susceptibility of mast cells to toxin-induced caspase activation, as detected using a fluorogenic substrate assay. Release of caspases during degranulation was accompanied by a decreased susceptibility to toxins. Zn depletion by chelation, but not by degranulation, also resulted in nuclear translocation of the antiapoptotic, proinflammatory transcription factor NF-kappaB. These findings implicate a role for ZnT(4) in mast cell Zn homeostasis and suggest that granule pools of Zn may be distinct from those regulating activation of procaspase-3 and NF-kappaB.
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Affiliation(s)
- Lien H Ho
- Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital, Woodville, South Australia 5011
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