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Damon LJ, Ocampo D, Sanford L, Jones T, Allen MA, Dowell RD, Palmer AE. Cellular zinc status alters chromatin accessibility and binding of transcription factor p53 to genomic sites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567954. [PMID: 38045276 PMCID: PMC10690171 DOI: 10.1101/2023.11.20.567954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Zinc (Zn2+) is an essential metal required by approximately 2500 proteins. Nearly half of these proteins act on DNA, including > 850 human transcription factors, polymerases, DNA damage response factors, and proteins involved in chromatin architecture. How these proteins acquire their essential Zn2+ cofactor and whether they are sensitive to changes in the labile Zn2+ pool in cells remain open questions. Here, we examine how changes in the labile Zn2+ pool affect chromatin accessibility and transcription factor binding to DNA. We observed both increases and decreases in accessibility in different chromatin regions via ATAC-seq upon treating MCF10A cells with elevated Zn2+ or the Zn2+-specific chelator tris(2-pyridylmethyl)amine (TPA). Transcription factor enrichment analysis was used to correlate changes in chromatin accessibility with transcription factor motifs, revealing 477 transcription factor motifs that were differentially enriched upon Zn2+ perturbation. 186 of these transcription factor motifs were enriched in Zn2+ and depleted in TPA, and the majority correspond to Zn2+ finger transcription factors. We selected TP53 as a candidate to examine how changes in motif enrichment correlate with changes in transcription factor occupancy by ChIP-qPCR. Using publicly available ChIP-seq and nascent transcription datasets, we narrowed the 50,000+ ATAC-seq peaks to 2164 TP53 targets and subsequently selected 6 high-probability TP53 binding sites for testing. ChIP-qPCR revealed that for 5 of the 6 targets, TP53 binding correlates with the local accessibility determined by ATAC-seq. These results demonstrate that changes in labile zinc directly alter chromatin accessibility and transcription factor binding to DNA.
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Affiliation(s)
- Leah J. Damon
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | - Daniel Ocampo
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | - Lynn Sanford
- Department of Molecular, Cellular, Developmental Biology, University of Colorado, Boulder, 80309
| | - Taylor Jones
- Department of Molecular, Cellular, Developmental Biology, University of Colorado, Boulder, 80309
| | - Mary A. Allen
- Department of Molecular, Cellular, Developmental Biology, University of Colorado, Boulder, 80309
- BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | - Robin D. Dowell
- Department of Molecular, Cellular, Developmental Biology, University of Colorado, Boulder, 80309
- BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | - Amy E. Palmer
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
- BioFrontiers Institute, University of Colorado, Boulder, CO 80303
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Dorward AM, Stewart AJ, Pitt SJ. The role of Zn2+ in shaping intracellular Ca2+ dynamics in the heart. J Gen Physiol 2023; 155:e202213206. [PMID: 37326614 PMCID: PMC10276528 DOI: 10.1085/jgp.202213206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/18/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Increasing evidence suggests that Zn2+ acts as a second messenger capable of transducing extracellular stimuli into intracellular signaling events. The importance of Zn2+ as a signaling molecule in cardiovascular functioning is gaining traction. In the heart, Zn2+ plays important roles in excitation-contraction (EC) coupling, excitation-transcription coupling, and cardiac ventricular morphogenesis. Zn2+ homeostasis in cardiac tissue is tightly regulated through the action of a combination of transporters, buffers, and sensors. Zn2+ mishandling is a common feature of various cardiovascular diseases. However, the precise mechanisms controlling the intracellular distribution of Zn2+ and its variations during normal cardiac function and during pathological conditions are not fully understood. In this review, we consider the major pathways by which the concentration of intracellular Zn2+ is regulated in the heart, the role of Zn2+ in EC coupling, and discuss how Zn2+ dyshomeostasis resulting from altered expression levels and efficacy of Zn2+ regulatory proteins are key drivers in the progression of cardiac dysfunction.
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Affiliation(s)
- Amy M. Dorward
- School of Medicine, University of St Andrews, St Andrews, UK
| | - Alan J. Stewart
- School of Medicine, University of St Andrews, St Andrews, UK
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Interactions of an Artificial Zinc Finger Protein with Cd(II) and Hg(II): Competition and Metal and DNA Binding. INORGANICS 2023. [DOI: 10.3390/inorganics11020064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cys2His2 zinc finger proteins are important for living organisms, as they—among other functions—specifically recognise DNA when Zn(II) is coordinated to the proteins, stabilising their ββα secondary structure. Therefore, competition with other metal ions may alter their original function. Toxic metal ions such as Cd(II) or Hg(II) might be especially dangerous because of their similar chemical properties to Zn(II). Most competition studies carried out so far have involved small zinc finger peptides. Therefore, we have investigated the interactions of toxic metal ions with a zinc finger proteins consisting of three finger units and the consequences on the DNA binding properties of the protein. Binding of one Cd(II) per finger subunit of the protein was shown by circular dichroism spectroscopy, fluorimetry and electrospray ionisation mass spectrometry. Cd(II) stabilised a similar secondary structure to that of the Zn(II)-bound protein but with a slightly lower affinity. In contrast, Hg(II) could displace Zn(II) quantitatively (logβ′ ≥ 16.7), demolishing the secondary structure, and further Hg(II) binding was also observed. Based on electrophoretic gel mobility shift assays, the Cd(II)-bound zinc finger protein could recognise the specific DNA target sequence similarly to the Zn(II)-loaded form but with a ~0.6 log units lower stability constant, while Hg(II) could destroy DNA binding completely.
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Choi TS, Tezcan FA. Design of a Flexible, Zn-Selective Protein Scaffold that Displays Anti-Irving-Williams Behavior. J Am Chem Soc 2022; 144:18090-18100. [PMID: 36154053 PMCID: PMC9949983 DOI: 10.1021/jacs.2c08050] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Selective metal binding is a key requirement not only for the functions of natural metalloproteins but also for the potential applications of artificial metalloproteins in heterogeneous environments such as cells and environmental samples. The selection of transition-metal ions through protein design can, in principle, be achieved through the appropriate choice and the precise positioning of amino acids that comprise the primary metal coordination sphere. However, this task is made difficult by the intrinsic flexibility of proteins and the fact that protein design approaches generally lack the sub-Å precision required for the steric selection of metal ions. We recently introduced a flexible/probabilistic protein design strategy (MASCoT) that allows metal ions to search for optimal coordination geometry within a flexible, yet covalently constrained dimer interface. In an earlier proof-of-principle study, we used MASCoT to generate an artificial metalloprotein dimer, (AB)2, which selectively bound CoII and NiII over CuII (as well as other first-row transition-metal ions) through the imposition of a rigid octahedral coordination geometry, thus countering the Irving-Williams trend. In this study, we set out to redesign (AB)2 to examine the applicability of MASCoT to the selective binding of other metal ions. We report here the design and characterization of a new flexible protein dimer, B2, which displays ZnII selectivity over all other tested metal ions including CuII both in vitro and in cellulo. Selective, anti-Irving-Williams ZnII binding by B2 is achieved through the formation of a unique trinuclear Zn coordination motif in which His and Glu residues are rigidly placed in a tetrahedral geometry. These results highlight the utility of protein flexibility in the design and discovery of selective binding motifs.
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Jomova K, Makova M, Alomar SY, Alwasel SH, Nepovimova E, Kuca K, Rhodes CJ, Valko M. Essential metals in health and disease. Chem Biol Interact 2022; 367:110173. [PMID: 36152810 DOI: 10.1016/j.cbi.2022.110173] [Citation(s) in RCA: 154] [Impact Index Per Article: 77.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/10/2022] [Accepted: 09/05/2022] [Indexed: 11/03/2022]
Abstract
In total, twenty elements appear to be essential for the correct functioning of the human body, half of which are metals and half are non-metals. Among those metals that are currently considered to be essential for normal biological functioning are four main group elements, sodium (Na), potassium (K), magnesium (Mg), and calcium (Ca), and six d-block transition metal elements, manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn) and molybdenum (Mo). Cells have developed various metallo-regulatory mechanisms for maintaining a necessary homeostasis of metal-ions for diverse cellular processes, most importantly in the central nervous system. Since redox active transition metals (for example Fe and Cu) may participate in electron transfer reactions, their homeostasis must be carefully controlled. The catalytic behaviour of redox metals which have escaped control, e.g. via the Fenton reaction, results in the formation of reactive hydroxyl radicals, which may cause damage to DNA, proteins and membranes. Transition metals are integral parts of the active centers of numerous enzymes (e.g. Cu,Zn-SOD, Mn-SOD, Catalase) which catalyze chemical reactions at physiologically compatible rates. Either a deficiency, or an excess of essential metals may result in various disease states arising in an organism. Some typical ailments that are characterized by a disturbed homeostasis of redox active metals include neurological disorders (Alzheimer's, Parkinson's and Huntington's disorders), mental health problems, cardiovascular diseases, cancer, and diabetes. To comprehend more deeply the mechanisms by which essential metals, acting either alone or in combination, and/or through their interaction with non-essential metals (e.g. chromium) function in biological systems will require the application of a broader, more interdisciplinary approach than has mainly been used so far. It is clear that a stronger cooperation between bioinorganic chemists and biophysicists - who have already achieved great success in understanding the structure and role of metalloenzymes in living systems - with biologists, will access new avenues of research in the systems biology of metal ions. With this in mind, the present paper reviews selected chemical and biological aspects of metal ions and their possible interactions in living systems under normal and pathological conditions.
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Affiliation(s)
- Klaudia Jomova
- Department of Chemistry, Faculty of Natural Sciences and Informatics, Constantine The Philosopher University in Nitra, 949 01, Nitra, Slovakia
| | - Marianna Makova
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, 812 37, Bratislava, Slovakia
| | - Suliman Y Alomar
- King Saud University, Zoology Department, College of Science, Riyadh, 11451, Saudi Arabia
| | - Saleh H Alwasel
- King Saud University, Zoology Department, College of Science, Riyadh, 11451, Saudi Arabia
| | - Eugenie Nepovimova
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, 50003 Hradec Kralove, Czech Republic
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, 50003 Hradec Kralove, Czech Republic; Biomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | | | - Marian Valko
- Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, 812 37, Bratislava, Slovakia; King Saud University, Zoology Department, College of Science, Riyadh, 11451, Saudi Arabia.
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6
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Bulathge AW, Villones RLE, Herbert FC, Gassensmith JJ, Meloni G. Comparative cisplatin reactivity towards human Zn7-metallothionein-2 and MTF-1 zinc fingers: potential implications in anticancer drug resistance. Metallomics 2022; 14:mfac061. [PMID: 36026541 PMCID: PMC9477119 DOI: 10.1093/mtomcs/mfac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/03/2022] [Indexed: 11/12/2022]
Abstract
Cis-diamminedichloroplatinum(II) (cisplatin) is a widely used metal-based chemotherapeutic drug for the treatment of cancers. However, intrinsic and acquired drug resistance limit the efficacy of cisplatin-based treatments. Increased production of intracellular thiol-rich molecules, in particular metallothioneins (MTs), which form stable coordination complexes with the electrophilic cisplatin, results in cisplatin sequestration leading to pre-target resistance. MT-1/-2 are overexpressed in cancer cells, and their expression is controlled by the metal response element (MRE)-binding transcription factor-1 (MTF-1), featuring six Cys2His2-type zinc fingers which, upon zinc metalation, recognize specific MRE sequences in the promoter region of MT genes triggering their expression. Cisplatin can efficiently react with protein metal binding sites featuring nucleophilic cysteine and/or histidine residues, including MTs and zinc fingers proteins, but the preferential reactivity towards specific targets with competing binding sites cannot be easily predicted. In this work, by in vitro competition reactions, we investigated the thermodynamic and kinetic preferential reactivity of cisplatin towards human Zn7MT-2, each of the six MTF-1 zinc fingers, and the entire human MTF-1 zinc finger domain. By spectroscopic, spectrometric, and electrophoretic mobility shift assays (EMSA), we demonstrated that cisplatin preferentially reacts with Zn7MT-2 to form Cys4-Pt(II) complexes, resulting in zinc release from MT-2. Zinc transfer from MT-2 to the MTF-1 triggers MTF-1 metalation, activation, and binding to target MRE sequences, as demonstrated by EMSA with DNA oligonucleotides. The cisplatin-dependent MT-mediated MTF-1 activation leading to apo-MT overexpression potentially establishes one of the molecular mechanisms underlying the development and potentiation of MT-mediated pre-target resistance.
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Affiliation(s)
- Anjala W Bulathge
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W Campbell Rd., Richardson, TX-75080, USA
| | - Rhiza Lyne E Villones
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W Campbell Rd., Richardson, TX-75080, USA
| | - Fabian C Herbert
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W Campbell Rd., Richardson, TX-75080, USA
| | - Jeremiah J Gassensmith
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W Campbell Rd., Richardson, TX-75080, USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W Campbell Rd., Richardson, TX-75080, USA
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Jackson TW, Baars O, Belcher SM. Gestational Cd Exposure in the CD-1 Mouse Sex-Specifically Disrupts Essential Metal Ion Homeostasis. Toxicol Sci 2022; 187:254-266. [PMID: 35212737 PMCID: PMC9154225 DOI: 10.1093/toxsci/kfac027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In CD-1 mice, gestational-only exposure to cadmium (Cd) causes female-specific hepatic insulin resistance, metabolic disruption, and obesity. To evaluate whether sex differences in uptake and changes in essential metal concentrations contribute to metabolic outcomes, placental and liver Cd and essential metal concentrations were quantified in male and female offspring perinatally exposed to 500 ppb CdCl2. Exposure resulted in increased maternal liver Cd+2 concentrations (364 µg/kg) similar to concentrations found in non-occupationally exposed human liver. At gestational day (GD) 18, placental Cd and manganese concentrations were significantly increased in exposed males and females, and zinc was significantly decreased in females. Placental efficiency was significantly decreased in GD18-exposed males. Increases in hepatic Cd concentrations and a transient prenatal increase in zinc were observed in exposed female liver. Fetal and adult liver iron concentrations were decreased in both sexes, and decreases in hepatic zinc, iron, and manganese were observed in exposed females. Analysis of GD18 placental and liver metallothionein mRNA expression revealed significant Cd-induced upregulation of placental metallothionein in both sexes, and a significant decrease in fetal hepatic metallothionein in exposed females. In placenta, expression of metal ion transporters responsible for metal ion uptake was increased in exposed females. In liver of exposed adult female offspring, expression of the divalent cation importer (Slc39a14/Zip14) decreased, whereas expression of the primary exporter (Slc30a10/ZnT10) increased. These findings demonstrate that Cd can preferentially cross the female placenta, accumulate in the liver, and cause lifelong dysregulation of metal ion concentrations associated with metabolic disruption.
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Affiliation(s)
- Thomas W Jackson
- Center for Human Health and the Environment, Department of Biological Sciences, North Carolina State University, 127 David Clark Labs Campus Box 7617, Raleigh, North Carolina 27695, USA
| | - Oliver Baars
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Scott M Belcher
- To whom correspondence should be addressed at Center for Human Health and the Environment, Department of Biological Sciences, North Carolina State University, 127 David Clark Labs Campus Box 7617, Raleigh, North Carolina 27695, USA. Tel.: (919) 513-1214. E-mail:
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8
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Han H, Nakaoka HJ, Hofmann L, Zhou JJ, Yu C, Zeng L, Nan J, Seo G, Vargas RE, Yang B, Qi R, Bardwell L, Fishman DA, Cho KWY, Huang L, Luo R, Warrior R, Wang W. The Hippo pathway kinases LATS1 and LATS2 attenuate cellular responses to heavy metals through phosphorylating MTF1. Nat Cell Biol 2022; 24:74-87. [PMID: 35027733 PMCID: PMC9022944 DOI: 10.1038/s41556-021-00813-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 11/08/2021] [Indexed: 12/11/2022]
Abstract
Heavy metals are both integral parts of cells and environmental toxicants, and their deregulation is associated with severe cellular dysfunction and various diseases. Here we show that the Hippo pathway plays a critical role in regulating heavy metal homeostasis. Hippo signalling deficiency promotes the transcription of heavy metal response genes and protects cells from heavy metal-induced toxicity, a process independent of its classic downstream effectors YAP and TAZ. Mechanistically, the Hippo pathway kinase LATS phosphorylates and inhibits MTF1, an essential transcription factor in the heavy metal response, resulting in the loss of heavy metal response gene transcription and cellular protection. Moreover, LATS activity is inhibited following heavy metal treatment, where accumulated zinc directly binds and inhibits LATS. Together, our study reveals an interplay between the Hippo pathway and heavy metals, providing insights into this growth-related pathway in tissue homeostasis and stress response.
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Affiliation(s)
- Han Han
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Hiroki J Nakaoka
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Line Hofmann
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Jeff Jiajing Zhou
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Lisha Zeng
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, USA
| | - Junyu Nan
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, USA
| | - Gayoung Seo
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | | | - Bing Yang
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Ruxi Qi
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen, China
| | - Lee Bardwell
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Dmitry A Fishman
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Ken W Y Cho
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA
| | - Ray Luo
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, USA
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, CA, USA
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Rahul Warrior
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA.
| | - Wenqi Wang
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA.
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Jia R, Song Z, Lin J, Li Z, Shan G, Huang C. Gawky modulates MTF-1-mediated transcription activation and metal discrimination. Nucleic Acids Res 2021; 49:6296-6314. [PMID: 34107019 PMCID: PMC8216474 DOI: 10.1093/nar/gkab474] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023] Open
Abstract
Metal-induced genes are usually transcribed at relatively low levels under normal conditions and are rapidly activated by heavy metal stress. Many of these genes respond preferentially to specific metal-stressed conditions. However, the mechanism by which the general transcription machinery discriminates metal stress from normal conditions and the regulation of MTF-1-meditated metal discrimination are poorly characterized. Using a focused RNAi screening in Drosophila Schneider 2 (S2) cells, we identified a novel activator, the Drosophila gawky, of metal-responsive genes. Depletion of gawky has almost no effect on the basal transcription of the metallothionein (MT) genes, but impairs the metal-induced transcription by inducing the dissociation of MTF-1 from the MT promoters and the deficient nuclear import of MTF-1 under metal-stressed conditions. This suggests that gawky serves as a 'checkpoint' for metal stress and metal-induced transcription. In fact, regular mRNAs are converted into gawky-controlled transcripts if expressed under the control of a metal-responsive promoter, suggesting that whether transcription undergoes gawky-mediated regulation is encrypted therein. Additionally, lack of gawky eliminates the DNA binding bias of MTF-1 and the transcription preference of metal-specific genes. This suggests a combinatorial control of metal discrimination by gawky, MTF-1, and MTF-1 binding sites.
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Affiliation(s)
- Ruirui Jia
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China
| | - Zhenxing Song
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China
| | - Jiamei Lin
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China
| | - Zhengguo Li
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China
| | - Ge Shan
- School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Chuan Huang
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Center of Plant Functional Genomics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China
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10
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Sensitivity and reliability of zinc transporter and metallothionein gene expression in peripheral blood mononuclear cells as indicators of zinc status: responses to ex vivo zinc exposure and habitual zinc intake in humans. Br J Nutr 2020; 125:361-368. [PMID: 32698913 DOI: 10.1017/s0007114520002810] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Zn is an essential nutrient for humans; however, a sensitive biomarker to assess Zn status has not been identified. The objective of this study was to determine the reliability and sensitivity of Zn transporter and metallothionein (MT) genes in peripheral blood mononuclear cells (PBMCs) to Zn exposure ex vivo and to habitual Zn intake in human subjects. In study 1, human PBMCs were cultured for 24 h with 0-50 µm ZnSO4 with or without 5 µm N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), and mRNA expression of SLC30A1-10, SLC39A1-14, MT1 subtypes (A, B, E, F, G, H, L, M and X), MT2A, MT3 and MT4 mRNA was determined. In study 2, fifty-four healthy male and female volunteers (31·9 (sd 13·8) years, BMI 25·7 (sd 2·9) kg/m2) completed a FFQ, blood was collected, PBMCs were isolated and mRNA expression of selected Zn transporters and MT isoforms was determined. Study 1: MT1E, MT1F, MT1G, MT1H, MT1L, MT1M, MT1X, MT2A and SLC30A1 increased with increasing concentrations of Zn and declined with the addition of TPEN. Study 2: Average daily Zn intake was 16·0 (sd 5·3) mg/d (range: 9-31 mg/d), and plasma Zn concentrations were 15·5 (SD 2·8) μmol/l (range 11-23 μmol/l). PBMC MT2A was positively correlated with dietary Zn intake (r 0·306, P = 0·03) and total Zn intake (r 0·382, P < 0·01), whereas plasma Zn was not (P > 0·05 for both). Findings suggest that MT2A mRNA in PBMCs reflects dietary Zn intake in healthy adults and may be a component in determining Zn status.
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11
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Aðalsteinsson HM, Lima FA, Galuppo C, Abbehausen C. Evaluation of cobalt complexes with tripod ligands for zinc finger targeting. Dalton Trans 2020; 49:16143-16153. [DOI: 10.1039/d0dt00067a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We report the ability of CoII and CoIII complexes of tri(2-pyridylmethyl)amine and N,N-di(2-pyridylmethyl)glycinate to disrupt zinc fingers.
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Affiliation(s)
| | - Frederico A. Lima
- European X-Ray Free-Electron Laser Facility GmbH
- 22869 Schenefeld
- Germany
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12
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Tavera-Montañez C, Hainer SJ, Cangussu D, Gordon SJV, Xiao Y, Reyes-Gutierrez P, Imbalzano AN, Navea JG, Fazzio TG, Padilla-Benavides T. The classic metal-sensing transcription factor MTF1 promotes myogenesis in response to copper. FASEB J 2019; 33:14556-14574. [PMID: 31690123 PMCID: PMC6894080 DOI: 10.1096/fj.201901606r] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/23/2019] [Indexed: 12/15/2022]
Abstract
Metal-regulatory transcription factor 1 (MTF1) is a conserved metal-binding transcription factor in eukaryotes that binds to conserved DNA sequence motifs, termed metal response elements. MTF1 responds to both metal excess and deprivation, protects cells from oxidative and hypoxic stresses, and is required for embryonic development in vertebrates. To examine the role for MTF1 in cell differentiation, we use multiple experimental strategies [including gene knockdown (KD) mediated by small hairpin RNA and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9), immunofluorescence, chromatin immunopreciptation sequencing, subcellular fractionation, and atomic absorbance spectroscopy] and report a previously unappreciated role for MTF1 and copper (Cu) in cell differentiation. Upon initiation of myogenesis from primary myoblasts, both MTF1 expression and nuclear localization increased. Mtf1 KD impaired differentiation, whereas addition of nontoxic concentrations of Cu+-enhanced MTF1 expression and promoted myogenesis. Furthermore, we observed that Cu+ binds stoichiometrically to a C terminus tetra-cysteine of MTF1. MTF1 bound to chromatin at the promoter regions of myogenic genes, and Cu addition stimulated this binding. Of note, MTF1 formed a complex with myogenic differentiation (MYOD)1, the master transcriptional regulator of the myogenic lineage, at myogenic promoters. These findings uncover unexpected mechanisms by which Cu and MTF1 regulate gene expression during myoblast differentiation.-Tavera-Montañez, C., Hainer, S. J., Cangussu, D., Gordon, S. J. V., Xiao, Y., Reyes-Gutierrez, P., Imbalzano, A. N., Navea, J. G., Fazzio, T. G., Padilla-Benavides, T. The classic metal-sensing transcription factor MTF1 promotes myogenesis in response to copper.
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Affiliation(s)
- Cristina Tavera-Montañez
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Sarah J. Hainer
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA; and
| | - Daniella Cangussu
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Shellaina J. V. Gordon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Yao Xiao
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, USA
| | - Pablo Reyes-Gutierrez
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Anthony N. Imbalzano
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Juan G. Navea
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, USA
| | - Thomas G. Fazzio
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA; and
| | - Teresita Padilla-Benavides
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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13
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Drechsel V, Fiechtner B, Höckner M. Promoter activity of earthworm metallothionein in mouse embryonic fibroblasts. Mol Biol Rep 2019; 46:6371-6379. [PMID: 31571111 DOI: 10.1007/s11033-019-05082-1] [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: 05/27/2019] [Accepted: 09/14/2019] [Indexed: 10/25/2022]
Abstract
The regulation of metallothionein (MT) gene expression as important part of the detoxification machinery is only scarcely known in invertebrates. In vertebrates, MT gene activation is mediated by the metal-transcription factor 1 (MTF-1) binding to metal response elements (MREs). In invertebrates, the mechanisms of MT gene activation seems to be more diverse. In some invertebrate species, MTF-1 orthologues as well as their ability to activate MT genes via MREs have been uncovered. Although earthworm MTs have been well studied, a MTF-1 orthologue has not yet been described and MT gene activation mechanisms are largely unknown. Analyses of the earthworm wMT2 promoter by reporter gene assays have been performed. We could show that the wMT2 promoter was active in mouse embryonic fibroblasts (NIH/3T3) as well as in mouse MTF-1-/-cells (DKO7). The presence of mouse MTF-1 (mMTF1) led to a significant increase in reporter gene activity. We observed that cadmium as well as zinc had an effect on promoter activity. In the presence of zinc, promoter activity doubled in NIH cells, however, we did not observe a significant effect in the DKO7 cell line. Cadmium decreased promoter activity in DKO7 cells, but this effect could be reversed by providing mMTF1 in a co-transfection experiment. We suggest that MT gene expression in the earthworm is not entirely dependent on a MRE binding protein. Interestingly, the shortest promoter fragment including MRE1 showed the highest promoter activity under control conditions.
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Affiliation(s)
- Victoria Drechsel
- Institute of Zoology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Birgit Fiechtner
- Institute of Zoology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Martina Höckner
- Institute of Zoology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
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14
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Fujie T, Takenaka F, Yoshida E, Yasuike S, Fujiwara Y, Shinkai Y, Kumagai Y, Yamamoto C, Kaji T. Possible mechanisms underlying transcriptional induction of metallothionein isoforms by tris(pentafluorophenyl)stibane, tris(pentafluorophenyl)arsane, and tris(pentafluorophenyl)phosphane in cultured bovine aortic endothelial cells. J Toxicol Sci 2019; 44:327-333. [PMID: 31068538 DOI: 10.2131/jts.44.327] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Metallothionein (MT) is a low-molecular-weight, cysteine-rich, and metal-binding protein that protects cells from the cytotoxic effects of heavy metals and reactive oxygen species. Previously, we found that transcriptional induction of endothelial MT-1A was mediated by not only the metal-regulatory transcription factor 1 (MTF-1)-metal responsive element (MRE) pathway but also the nuclear factor-erythroid 2-related factor 2 (Nrf2)-antioxidant response element/electrophile responsive element (ARE) pathway, whereas that of MT-2A was mediated only by the MTF-1-MRE pathway, using the organopnictogen compounds tris(pentafluorophenyl)stibane, tris(pentafluorophenyl)arsane, and tris(pentafluorophenyl)phosphane as molecular probes in vascular endothelial cells. In the present study, we investigated the binding sites of MTF-1 and Nrf2 in the promoter regions of MTs in cultured bovine aortic endothelial cells treated with these organopnictogen compounds. We propose potential mechanisms underlying transcriptional induction of endothelial MT isoforms. Specifically, both MRE activation by MTF-1 and that of ARE in the promoter region of the MT-2A gene by Nrf2 are involved in transcriptional induction of MT-1A, whereas only MRE activation by MTF-1 or other transcriptional factor(s) is required for transcriptional induction of MT-2A in vascular endothelial cells.
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Affiliation(s)
- Tomoya Fujie
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Toho University
| | - Fukuta Takenaka
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Eiko Yoshida
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Shuji Yasuike
- Laboratory of Organic and Medicinal Chemistry, School of Pharmaceutical Sciences, Aichi Gakuin University
| | - Yasuyuki Fujiwara
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Yasuhiro Shinkai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba
| | - Chika Yamamoto
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Toho University
| | - Toshiyuki Kaji
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
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15
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Park C, Jeong J. Synergistic cellular responses to heavy metal exposure: A minireview. Biochim Biophys Acta Gen Subj 2018; 1862:1584-1591. [PMID: 29631058 DOI: 10.1016/j.bbagen.2018.04.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 03/22/2018] [Accepted: 04/04/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Metal-responsive transcription factor 1 (MTF-1) induces the expression of metallothioneins (MTs) which bind and sequester labile metal ions. While MTF-1 primarily responds to excess metal exposure, additional stress response mechanisms are activated by excess metals. Evidence suggests potential crosstalk between responses mediated by MTF-1 and stress signaling enhances cellular tolerance to metal exposure. SCOPE OF REVIEW This review aims to summarize the current understanding of interaction between the stress response mediated by MTF-1 and other cellular mechanisms, notably the nuclear factor κB (NF-κB) and heat shock response (HSR). MAJOR CONCLUSIONS Crosstalk between MTF-1 mediated metal response and NF-κB signaling or HSR can modulate expression of stress proteins in response to metal exposure via effects on precursor signals or direct interaction of transcriptional activators. The interaction between stress signaling pathways can enhance cell survival and tolerance through a unified response system. GENERAL SIGNIFICANCE Elucidating the interactions between MTF-1 and cell stress response mechanisms is critical to a comprehensive understanding of metal-based cellular effects. Co-activation of HSR and NF-κB signaling allows the cell to detect metal contamination in the environment and improve survival outcomes.
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Affiliation(s)
- Chanyoung Park
- Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, United States
| | - Jeeyon Jeong
- Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, United States; Department of Biology, Amherst College, Amherst, MA 01002, United States.
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16
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Wang C, Shu F, Hong Y, Wang J, Peng K, Sheng J, Wu D, Hu B, Shi J, Jian S. Analysis of the structure and activity of the promoter regions of the metallothionein genes of the freshwater pearl mussel Hyriopsis schlegelii. Biosci Biotechnol Biochem 2018; 82:780-791. [PMID: 29499631 DOI: 10.1080/09168451.2018.1443788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
To investigate the regulation of metallothionein genes (HsMTs) of Hyriopsis schlegelii, 1,121-bp and 1,270-bp regions of the HsMT1 and HsMT2 promoters were cloned and analyzed, respectively. The two promoters shared partially conserved features and possessed distinct characteristics such as the number or position of metal response elements (MREs). Further analysis of the HsMT1 and HsMT2 promoters was performed by the reporter assay using the luciferase gene. Both promoters were activated by various metals, and presented different levels of metal ions inducibility in human hepatoblastoma cells. Deletion mutant assays demonstrated that both the longest promoter regions achieved the maximum inducibility, and the metal inducibility was dependent on the presence of the MRE in HsMT1 and the distal MRE in HsMT2. In addition, we cloned a putative metal responsive transcription factor (hereby designated as HsMTF-like) and studied its effect on HsMTs expression in human hepatoblastoma cells. An in vivo assay demonstrated that HsMTF-like activates basal HsMTs transcription level, and the MRE in the HsMTs promoter mediates this activation process. Moreover, this basal transcription level can be further boosted by zinc treatment. In conclusion, the regulation mechanism for MT activation in H. schlegelii should be evolutionarily conserved.
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Affiliation(s)
- Chengyuan Wang
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Fuxing Shu
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Yijiang Hong
- School of Life Sciences, Nanchang University, Nanchang, China.,Key Laboratory of Aquatic Resources and Utilization of Jiangxi, Nanchang University, Nanchang, China
| | - Junhua Wang
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Kou Peng
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Junqing Sheng
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Di Wu
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Beijuan Hu
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Jianwu Shi
- School of Life Sciences, Nanchang University, Nanchang, China
| | - Shaoqing Jian
- School of Life Sciences, Nanchang University, Nanchang, China
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17
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Abstract
The cellular constitution of Zn-proteins and Zn-dependent signaling depend on the capacity of Zn2+ to find specific binding sites in the face of a plethora of other high affinity ligands. The most prominent of these is metallothionein (MT). It serves as a storage site for Zn2+ under various conditions, and has chemical properties that support a dynamic role for MT in zinc trafficking. Consistent with these characteristics, changing the availability of zinc for cells and tissues causes rapid alteration of zinc bound to MT. Nevertheless, zinc trafficking occurs in metallothionein-null animals and cells, hypothetically making use of proteomic binding sites to mediate the intracellular movements of zinc. Like metallothionein, the proteome contains a large concentration of proteins that strongly coordinate zinc. In this environment, free Zn2+ may be of little significance. Instead, this review sets forth the basis for the hypothesis that components of the proteome and MT jointly provide the platform for zinc trafficking.
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Affiliation(s)
- David H Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53217, USA.
| | - Afsana Mahim
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53217, USA.
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18
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Hu X, Fernandes J, Jones DP, Go YM. Cadmium stimulates myofibroblast differentiation and mouse lung fibrosis. Toxicology 2017; 383:50-56. [PMID: 28341147 DOI: 10.1016/j.tox.2017.03.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/26/2017] [Accepted: 03/20/2017] [Indexed: 12/15/2022]
Abstract
Increasing evidence suggests that Cd at levels found in the human diet can cause oxidative stress and activate redox-sensitive transcription factors in inflammatory signaling. Following inflammation, tissue repair often involves activation of redox-sensitive transcription factors in fibroblasts. In lungs, epithelial barrier remodeling is required to restore gas exchange and barrier function, and aberrant myofibroblast differentiation leads to pulmonary fibrosis. Contributions of exogenous exposures, such as dietary Cd, to pulmonary fibrosis remain incompletely defined. In the current study, we tested whether Cd activates fibrotic signaling in human fetal lung fibroblasts (HFLF) at micromolar and submicromolar Cd concentrations that do not cause cell death. Exposure of HFLF to low-dose Cd (≤1.0μM) caused an increase in stress fibers and increased protein levels of myofibroblast differentiation markers, including α-smooth muscle actin (α-SMA) and extra-domain-A-containing fibronectin (ED-A-FN). Assay of transcription factor (TF) activity using a 45-TF array showed that Cd increased activity of 12 TF, including SMAD2/3/4 (mothers against decapentaplegic homolog) signaling differentiation and fibrosis. Results were confirmed by real-time PCR and supported by increased expression of target genes of SMAD2/3/4. Immunocytochemistry of lungs of mice exposed to low-dose Cd (0.3 and 1.0mg/L in drinking water) showed increased α-SMA protein level with lung Cd accumulation similar to lung Cd in non-smoking humans. Together, the results show that relatively low Cd exposures stimulate pulmonary fibrotic signaling and myofibroblast differentiation by activating SMAD2/3/4-dependent signaling. The results indicate that dietary Cd intake could be an important variable contributing to pulmonary fibrosis in humans.
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Affiliation(s)
- Xin Hu
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, GA 30322, United States
| | - Jolyn Fernandes
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, GA 30322, United States
| | - Dean P Jones
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, GA 30322, United States
| | - Young-Mi Go
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, GA 30322, United States.
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19
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Petering DH. Reactions of the Zn Proteome with Cd2+ and Other Xenobiotics: Trafficking and Toxicity. Chem Res Toxicol 2016; 30:189-202. [DOI: 10.1021/acs.chemrestox.6b00328] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- David H. Petering
- Department of Chemistry and
Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53201, United States
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20
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Fujie T, Murakami M, Yoshida E, Yasuike S, Kimura T, Fujiwara Y, Yamamoto C, Kaji T. Transcriptional Induction of Metallothionein by Tris(pentafluorophenyl)stibane in Cultured Bovine Aortic Endothelial Cells. Int J Mol Sci 2016; 17:E1381. [PMID: 27563876 PMCID: PMC5037661 DOI: 10.3390/ijms17091381] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/05/2016] [Accepted: 08/16/2016] [Indexed: 12/29/2022] Open
Abstract
Vascular endothelial cells cover the luminal surface of blood vessels and contribute to the prevention of vascular disorders such as atherosclerosis. Metallothionein (MT) is a low molecular weight, cysteine-rich, metal-binding, inducible protein, which protects cells from the toxicity of heavy metals and active oxygen species. Endothelial MT is not induced by inorganic zinc. Adequate tools are required to investigate the mechanisms underlying endothelial MT induction. In the present study, we found that an organoantimony compound, tris(pentafluorophenyl)stibane, induces gene expression of MT-1A and MT-2A, which are subisoforms of MT in bovine aortic endothelial cells. The data reveal that MT-1A is induced by activation of both the MTF-1-MRE and Nrf2-ARE pathways, whereas MT-2A expression requires only activation of the MTF-1-MRE pathway. The present data suggest that the original role of MT-1 is to protect cells from heavy metal toxicity and oxidative stress in the biological defense system, while that of MT-2 is to regulate intracellular zinc metabolism.
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Affiliation(s)
- Tomoya Fujie
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
| | - Masaki Murakami
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
| | - Eiko Yoshida
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
| | - Shuji Yasuike
- Laboratory of Organic and Medicinal Chemistry, School of Pharmaceutical Sciences, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
| | - Tomoki Kimura
- Depertment of Life Science, Faculty of Science and Engineering, Setsunan University, 17-8 Ikedanakamachi, Neyagawa 572-8508, Japan.
| | - Yasuyuki Fujiwara
- Department of Environmental Health, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji 192-0392, Japan.
| | - Chika Yamamoto
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan.
| | - Toshiyuki Kaji
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
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21
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Dietrich N, Tan CH, Cubillas C, Earley BJ, Kornfeld K. Insights into zinc and cadmium biology in the nematode Caenorhabditis elegans. Arch Biochem Biophys 2016; 611:120-133. [PMID: 27261336 DOI: 10.1016/j.abb.2016.05.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/18/2016] [Accepted: 05/28/2016] [Indexed: 10/21/2022]
Abstract
Zinc is an essential metal that is involved in a wide range of biological processes, and aberrant zinc homeostasis is implicated in multiple human diseases. Cadmium is chemically similar to zinc, but it is a nonessential environmental pollutant. Because zinc deficiency and excess are deleterious, animals require homeostatic mechanisms to maintain zinc levels in response to dietary fluctuations. The nematode Caenorhabditis elegans is emerging as a powerful model system to investigate zinc trafficking and homeostasis as well as cadmium toxicity. Here we review genetic and molecular studies that have combined to generate a picture of zinc homeostasis based on the transcriptional control of zinc transporters in intestinal cells. Furthermore, we summarize studies of cadmium toxicity that reveal intriguing parallels with zinc biology.
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Affiliation(s)
- Nicholas Dietrich
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, United States.
| | - Chieh-Hsiang Tan
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Ciro Cubillas
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Brian James Earley
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, United States
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, United States
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22
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Fujie T, Segawa Y, Uehara A, Nakamura T, Kimura T, Yoshida E, Yamamoto C, Uchiyama M, Naka H, Kaji T. Zinc diethyldithiocarbamate as an inducer of metallothionein in cultured vascular endothelial cells. J Toxicol Sci 2016; 41:217-24. [PMID: 26961605 DOI: 10.2131/jts.41.217] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Vascular endothelial cells are in direct contact with blood. Inorganic zinc is thought to be incapable of inducing metallothionein, which protects cells from heavy metal toxicity and oxidative stress, in vascular endothelial cells. Here, we aimed to further characterize the induction of metallothionein in vascular endothelial cells. Our results confirmed that inorganic zinc could not induce metallothionein in vascular endothelial cells. Moreover, ZnSO4 could not activate both the metal response element (MRE) transcription factor 1 (MTF-1)/MRE and Nrf2/antioxidant response element (ARE) pathways and was incapable of inducing metallothionein. In addition, bis(L-cysteinato)zincate(II), a zinc complex that activates the MTF-1/MRE pathway, increased MRE promoter activity but failed to induce metallothionein, suggesting that vascular endothelial metallothionein was not induced only by activation of the MTF-1/MRE pathway. Further analysis of a library of zinc complexes showed that zinc(II) bis(diethyldithiocarbamate) activated the MTF-1/MRE pathway but not the Nrf2/ARE pathway, increased MT-1A, MT-1E, and MT-2A mRNA levels, and induced metallothionein proteins. These data indicated that zinc complexes may be excellent tools to analyze metallothionein induction in vascular endothelial cells.
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Affiliation(s)
- Tomoya Fujie
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
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23
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Fujie T, Segawa Y, Yoshida E, Kimura T, Fujiwara Y, Yamamoto C, Satoh M, Naka H, Kaji T. Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells. J Toxicol Sci 2016; 41:225-32. [PMID: 26961606 DOI: 10.2131/jts.41.225] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Metallothionein (MT) plays a central role in cellular defense against heavy metals and oxidative stress. Since the induction of MT requires the activation of metal response element (MRE)-binding transcription factor-1 (MTF-1) by binding of zinc ions, inorganic zinc is regarded as a typical MT inducer. However, in a previous report, we showed that inorganic zinc could not induce MT in vascular endothelial cells. While it is suggested that endothelial MT presents mechanisms different from those of other cell types, these remain unclear. In this study, we investigated whether the induction of endothelial MT expression involves the Nrf2-ARE pathway using copper(II) bis(diethyldithiocarbamate), termed Cu10, using a culture system of bovine aortic endothelial cells. Cu10 induced MT-1/2 protein expression and increased the expression of mRNAs for MT-1A, MT-1E, and MT-2, MT isoforms expressed in the cells. Cu10 activated not only the MTF-1-MRE, but also the Nrf2-ARE pathway. MTF-1 knockdown resulted in the repression of Cu10-induced MT-1 and -2 expression. Cu10-induced MT-1 expression was down-regulated by Nrf2 knockdown. However, MT-2 expression was not affected by Nrf2 knockdown. These results suggest that the expression of endothelial MT is up-regulated by the Nrf2-ARE pathway as well as by the MTF-1-MRE pathway. Moreover, MT-1 regulation mechanisms differ from that of MT-2. Specifically, the present data support the hypothesis that MT-1 participates in the biological defense system, while MT-2 mainly regulates intracellular zinc metabolism.
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Affiliation(s)
- Tomoya Fujie
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
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24
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Liu TP, Hong YH, Tung KY, Yang PM. In silico and experimental analyses predict the therapeutic value of an EZH2 inhibitor GSK343 against hepatocellular carcinoma through the induction of metallothionein genes. Oncoscience 2016; 3:9-20. [PMID: 26973856 PMCID: PMC4751912 DOI: 10.18632/oncoscience.285] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 01/22/2016] [Indexed: 12/24/2022] Open
Abstract
There are currently no effective molecular targeted therapies for hepatocellular carcinoma (HCC), the third leading cause of cancer-related death worldwide. Enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27 (H3K27)-specific methyltransferase, has been emerged as novel anticancer target. Our previous study has demonstrated that GSK343, an S-adenosyl-L-methionine (SAM)-competitive inhibitor of EZH2, induces autophagy and enhances drug sensitivity in cancer cells including HCC. In this study, an in silico study was performed and found that EZH2 was overexpressed in cancerous tissues of HCC patients at both gene and protein levels. Microarray analysis and in vitro experiments indicated that the anti-HCC activity of GSK343 was associated with the induction of metallothionein (MT) genes. In addition, the negative association of EZH2 and MT1/MT2A genes in cancer cell lines and tissues was found in public gene expression database. Taken together, our findings suggest that EZH2 inhibitors could be a good therapeutic option for HCC, and induction of MT genes was associated with the anti-HCC activity of EZH2 inhibitors.
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Affiliation(s)
- Tsang-Pai Liu
- The Ph.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; Department of Surgery, Mackay Memorial Hospital, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing and Management, New Taipei City, Taiwan; Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Liver Medical Center, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yi-Han Hong
- Department of Surgery, Mackay Memorial Hospital, Taipei, Taiwan
| | - Kwang-Yi Tung
- Department of Surgery, Mackay Memorial Hospital, Taipei, Taiwan
| | - Pei-Ming Yang
- The Ph.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
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25
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Wooten DC, Starr CR, Lyon WJ. A plasmid containing the human metallothionein II gene can function as an antibody-assisted electrophoretic biosensor for heavy metals. J Immunotoxicol 2015; 13:55-63. [PMID: 25594566 DOI: 10.3109/1547691x.2014.999295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Different forms of heavy metals affect biochemical systems in characteristic ways that cannot be detected with typical metal analysis methods like atomic absorption spectrometry. Further, using living systems to analyze interaction of heavy metals with biochemical systems can be laborious and unreliable. To generate a reliable easy-to-use biologically-based biosensor system, the entire human metallothionein-II (MT-II) gene was incorporated into a plasmid (pUC57-MT) easily replicated in Escherichia coli. In this system, a commercial polyclonal antibody raised against human metal-responsive transcription factor-1 protein (MTF-1 protein) could modify the electrophoretic migration patterns (i.e. cause specific decreases in agarose gel electrophoretic mobility) of the plasmid in the presence or absence of heavy metals other than zinc (Zn). In the study here, heavy metals, MTF-1 protein, and polyclonal anti-MTF-1 antibody were used to assess pUC57-MT plasmid antibody-assisted electrophoretic mobility. Anti-MTF-1 antibody bound both MTF-1 protein and pUC57-MT plasmid in a non-competitive fashion such that it could be used to differentiate specific heavy metal binding. The results showed that antibody-inhibited plasmid migration was heavy metal level-dependent. Zinc caused a unique mobility shift pattern opposite to that of other metals tested, i.e. Zn blocked the antibody ability to inhibit plasmid migration, despite a greatly increased affinity for DNA by the antibody when Zn was present. The Zn effect was reversed/modified by adding MTF-1 protein. Additionally, antibody inhibition of plasmid mobility was resistant to heat pre-treatment and trypsinization, indicating absence of residual DNA extraction-resistant bacterial DNA binding proteins. DNA binding by anti-DNA antibodies may be commonly enhanced by xenobiotic heavy metals and elevated levels of Zn, thus making them potentially effective tools for assessment of heavy metal bioavailability in aqueous solutions and fluid obtained from metal implant sites.
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Affiliation(s)
- Dennis C Wooten
- a United States Air Force School of Aerospace Medicine, Advanced Technology and Genetics Center, Wright-Patterson Air Force Base , OH , USA
| | - Clarise R Starr
- a United States Air Force School of Aerospace Medicine, Advanced Technology and Genetics Center, Wright-Patterson Air Force Base , OH , USA
| | - Wanda J Lyon
- a United States Air Force School of Aerospace Medicine, Advanced Technology and Genetics Center, Wright-Patterson Air Force Base , OH , USA
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Gauthier PT, Norwood WP, Prepas EE, Pyle GG. Metal-PAH mixtures in the aquatic environment: a review of co-toxic mechanisms leading to more-than-additive outcomes. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:253-69. [PMID: 24929353 DOI: 10.1016/j.aquatox.2014.05.026] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 05/10/2023]
Abstract
Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in aquatic environments, yet relatively little is known regarding their combined toxicities. Emerging reports investigating the additive mortality in metal-PAH mixtures have indicated that more-than-additive effects are equally as common as strictly-additive effects, raising concern for ecological risk assessment typically based on the summation of individual toxicities. Moreover, the current separation of focus between in vivo and in vitro studies, and fine- and coarse-scale endpoints, creates uncertainty regarding the mechanisms of co-toxicity involved in more-than-additive effects on whole organisms. Drawing from literature on metal and PAH toxicity in bacteria, protozoa, invertebrates, fish, and mammalian models, this review outlines several key mechanistic interactions likely to promote more-than-additive toxicity in metal-PAH mixtures. Namely, the deleterious effects of PAHs on membrane integrity and permeability to metals, the potential for metal-PAH complexation, the inhibitory nature of metals to the detoxification of PAHs via the cytochrome P450 pathway, the inhibitory nature of PAHs towards the detoxification of metals via metallothionein, and the potentiated production of reactive oxygenated species (ROS) in certain metal (e.g. Cu) and PAH (e.g., phenanthrenequinone) mixtures. Moreover, the mutual inhibition of detoxification suggests the possibility of positive feedback among these mechanisms. The individual toxicities and interactive aspects of contaminant transport, detoxification, and the production of ROS are herein discussed.
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Affiliation(s)
- Patrick T Gauthier
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ON, Canada P7B 5E1.
| | - Warren P Norwood
- Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6
| | - Ellie E Prepas
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ON, Canada P7B 5E1
| | - Greg G Pyle
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
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Zhao WJ, Song Q, Wang YH, Li KJ, Mao L, Hu X, Lian HZ, Zheng WJ, Hua ZC. Zn-responsive proteome profiling and time-dependent expression of proteins regulated by MTF-1 in A549 cells. PLoS One 2014; 9:e105797. [PMID: 25162517 PMCID: PMC4146543 DOI: 10.1371/journal.pone.0105797] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/24/2014] [Indexed: 12/11/2022] Open
Abstract
Zinc plays a critical role in many biological processes. However, it is toxic at high concentrations and its homeostasis is strictly regulated by metal-responsive transcription factor 1 (MTF-1) together with many other proteins to protect cells against metal toxicity and oxidative stresses. In this paper, we used high-resolution two-dimensional gel electrophoresis (2DE) to profile global changes of the whole soluble proteome in human lung adenocarcinoma (A549) cells in response to exogenous zinc treatment for 24 h. Eighteen differentially expressed proteins were identified by MALDI TOF/TOF and MASCOT search. In addition, we used Western blotting and RT-PCR to examine the time-dependent changes in expression of proteins regulated by MTF-1 in response to Zn treatment, including the metal binding protein MT-1, the zinc efflux protein ZnT-1, and the zinc influx regulator ZIP-1. The results indicated that variations in their mRNA and protein levels were consistent with their functions in maintaining the homeostasis of zinc. However, the accumulation of ZIP-1 transcripts was down-regulated while the protein level was up-regulated during the same time period. This may be due to the complex regulatory mechanism of ZIP-1, which is involved in multiple signaling pathways. Maximal changes in protein abundance were observed at 10 h following Zn treatment, but only slight changes in protein or mRNA levels were observed at 24 h, which was the time-point frequently used for 2DE analyses. Therefore, further study of the time-dependent Zn-response of A549 cells would help to understand the dynamic nature of the cellular response to Zn stress. Our findings provide the basis for further study into zinc-regulated cellular signaling pathways.
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Affiliation(s)
- Wen-jie Zhao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, PR China
| | - Qun Song
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, PR China
| | - Yan-hong Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, PR China
| | - Ke-jin Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing, PR China
| | - Li Mao
- MOE Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing, PR China
| | - Xin Hu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, PR China
| | - Hong-zhen Lian
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, Nanjing, PR China
| | - Wei-juan Zheng
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing, PR China
| | - Zi-chun Hua
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Science, Nanjing University, Nanjing, PR China
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Georgiev O, Günther V, Steiner K, Schönrath K, Schaffner W. The legless lizard Anguis fragilis (slow worm) has a potent metal-responsive transcription factor 1 (MTF-1). Biol Chem 2014; 395:425-31. [PMID: 24413216 DOI: 10.1515/hsz-2013-0293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/07/2014] [Indexed: 12/16/2023]
Abstract
The metal-responsive transcription factor-1 (MTF-1) is a key regulator of heavy metal homeostasis and detoxification. Here we characterize the first MTF-1 from a reptile, the slow worm Anguis fragilis. The slow worm, or blind worm, is a legless lizard also known for its long lifespan of up to several decades. Anguis MTF-1 performs well and matches the strong zinc and cadmium response of its human ortholog, clearly surpassing the activity of rodent MTF-1s. Some amino acid positions critical for metal response are the same in humans and slow worm but not in rodent MTF-1. This points to a divergent evolution of rodent MTF-1, and we speculate that rodents can afford a less sophisticated metal handling than humans and (some) reptiles.
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Rembach A, Hare DJ, Doecke JD, Burnham SC, Volitakis I, Fowler CJ, Cherny RA, McLean C, Grimm R, Martins R, Ames D, Masters CL, Bush AI, Roberts BR. Decreased serum zinc is an effect of ageing and not Alzheimer's disease. Metallomics 2014; 6:1216-9. [DOI: 10.1039/c4mt00060a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Serum zinc decreases with age.
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Affiliation(s)
- Alan Rembach
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Dominic J. Hare
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
- Elemental Bio-imaging Centre
- University of Technology
| | - James D. Doecke
- CSIRO Preventative Health Flagship: Mathematics, Informatics and Statistics
- Perth, Australia
- The Australian e-Health Research Centre
- Herston, Australia
| | - Samantha C. Burnham
- CSIRO Preventative Health Flagship: Mathematics, Informatics and Statistics
- Perth, Australia
| | - Irene Volitakis
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Christopher J. Fowler
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Robert A. Cherny
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | | | | | - Ralph Martins
- James McCusker Alzheimer's Disease Research Unit
- Health Department of Western Australia
- , Australia
| | - David Ames
- National Ageing Research Institute
- Parkville, Australia
| | - Colin L. Masters
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Ashley I. Bush
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
| | - Blaine R. Roberts
- The Florey Institute of Neuroscience and Mental Health
- The University of Melbourne
- Parkville, Australia
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Cuillel M, Chevallet M, Charbonnier P, Fauquant C, Pignot-Paintrand I, Arnaud J, Cassio D, Michaud-Soret I, Mintz E. Interference of CuO nanoparticles with metal homeostasis in hepatocytes under sub-toxic conditions. NANOSCALE 2014; 6:1707-1715. [PMID: 24343273 DOI: 10.1039/c3nr05041f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Copper oxide nanoparticles (CuO-NP) were studied for their toxicity and mechanism of action on hepatocytes (HepG2), in relation to Cu homeostasis disruption. Indeed, hepatocytes, in the liver, are responsible for the whole body Cu balance and should be a major line of defence in the case of exposure to CuO-NP. We investigated the early responses to sub-toxic doses of CuO-NP and compared them to equivalent doses of Cu added as salt to see if there is a specific nano-effect related to Cu homeostasis in hepatocytes. The expression of the genes encoding the Cu-ATPase ATP7B, metallothionein 1X, heme oxygenase 1, heat shock protein 70, superoxide dismutase 1, glutamate cysteine ligase modifier subunit, metal responsive element-binding transcription factor 1 and zinc transporter 1 was analyzed by qRT-PCR. These genes are known to be involved in response to Cu, Zn and/or oxidative stresses. Except for MTF1, ATP7B and SOD1, we clearly observed an up regulation of these genes expression in CuO-NP treated cells, as compared to CuCl2. In addition, ATP7B trafficking from the Golgi network to the bile canaliculus membrane was observed in WIF-B9 cells, showing a need for Cu detoxification. This shows an increase in the intracellular Cu concentration, probably due to Cu release from endosomal CuO-NP solubilisation. Our data show that CuO-NP enter hepatic cells, most probably by endocytosis, bypassing the cellular defence mechanism against Cu, thus acting as a Trojan horse. Altogether, this study suggests that sub-toxic CuO-NP treatments induce successively a Cu overload, a Cu-Zn exchange on metallothioneins and MTF1 regulation on both Cu and Zn homeostasis.
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31
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Shen SF, Wang RL, Lu L, Li SF, Liu SB, Xie JJ, Zhang LY, Wang ML, Luo XG. Effect of intravenously injected zinc on tissue zinc and metallothionein gene expression of broilers. Br Poult Sci 2013; 54:381-90. [PMID: 23705842 DOI: 10.1080/00071668.2013.787158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
1. The effect of intravenously injected zinc (Zn) on tissue Zn concentrations and pancreas metallothionein (MT) gene expression in broilers was investigated to detect differences in the tissue utilisation of Zn from different Zn sources. 2. A total of 432 male chickens were randomly allotted on d 22 post-hatch to one of nine treatments in a completely randomised design. Chickens were injected with either a 0.9% (w/v) NaCl solution (control) or a saline solution supplemented with Zn sulphate or one of three organic Zn chelates with weak (Zn-AA W), moderate (Zn-Pro M) or strong (Zn-Pro S) chelation strengths at two injected Zn dosages calculated according to two Zn absorbability levels (6 and 12%). 3. Bone and pancreas Zn concentrations, pancreas MT mRNA levels and MT concentrations increased on d 6 and 12 after Zn injections as the injected Zn dosages increased. Chickens injected with the Zn-Pro S had lower bone Zn concentration than those injected with the Zn-Pro M or Zn-AA W on d 6 after injections. However, no differences among Zn sources were observed in bone Zn concentration on d 12 after injections, pancreas Zn concentrations, pancreas MT mRNA levels and MT concentrations on both d 6 and d 12 after injections. 4. It was concluded that the injected Zn-Pro S was the least favourable for bone Zn utilisation of broilers. The pancreas Zn concentration and pancreas MT gene expressions might not be sensitive enough to detect differences in the tissue utilisation of injected Zn in broilers between organic and inorganic Zn sources or among organic Zn sources.
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Affiliation(s)
- S F Shen
- Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences,No. 2Yuanmingyuan West Road, Haidian, Beijing, People's Republic of China
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32
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Yu Y, Wu A, Zhang Z, Yan G, Zhang F, Zhang L, Shen X, Hu R, Zhang Y, Zhang K, Wang F. Characterization of the GufA subfamily member SLC39A11/Zip11 as a zinc transporter. J Nutr Biochem 2013; 24:1697-708. [PMID: 23643525 DOI: 10.1016/j.jnutbio.2013.02.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 01/29/2013] [Accepted: 02/14/2013] [Indexed: 11/18/2022]
Abstract
Cellular zinc influx and efflux are maintained by two major transporter families, the ZIP (SLC39A) and ZnT (SLC30A or CDF) molecules. The functions of one molecule in this class, ZIP11/SLC39A11, remain unclear. Bioinformatics analysis of the distribution and evolutionary relationships of different ZIP members in eukaryotes and prokaryotes indicated that Zip11, the sole member of gufA subfamily, is an ancient ZIP family member that might have originated in early eukaryotic ancestors. Murine Zip11 mRNA is abundantly expressed in testes and the digestive system including stomach, ileum and cecum. Analysis of cellular zinc content, metallothionein levels, and cell viability under high or low zinc conditions in cells transfected with a murine Zip11 expression plasmid, suggest that Zip11 is a zinc importer. Further, cellular zinc concentrations and metallothionein levels decreased when Zip11 was knocked down. In mice supplemented with zinc, both mRNA and protein levels of Zip11 were slightly up-regulated in several tissues. The metal response element sequences (MREs) upstream of the first exon of Zip11 responded to elevated extracellular zinc concentrations, as assessed by luciferase reporter assays. Mutagenic analysis showed that several of the MREs could regulate Zip11 promoter activity, and metal-responsive transcription factor-1 (MTF-1) was shown to be involved in this process. Collectively, these data suggest that Zip11 has unique protein sequence and structure features, it functions as a cellular zinc transporter, and its expression is at least partially regulated by zinc via hMTF-1 binding to MREs of the Zip11 promoter.
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Affiliation(s)
- Yu Yu
- Department of Nutrition, Institute of Nutrition and Food Safety, School of Public Health, Zhejiang University, Hangzhou 310058, P.R. China; Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
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Qiu J, Liu Y, Yu M, Pang Z, Chen W, Xu Z. Identification and functional characterization of MRE-binding transcription factor (MTF) in Crassostrea gigas and its conserved role in metal-induced response. Mol Biol Rep 2013; 40:3321-31. [PMID: 23271123 DOI: 10.1007/s11033-012-2407-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 12/18/2012] [Indexed: 10/27/2022]
Abstract
The full-length cDNA that encodes the MRE-binding transcription factor (MTF) was cloned from the Pacific oyster (Crassostrea gigas) using reverse transcription polymerase chain reaction and the rapid amplification of cDNA ends. The cgMTF cDNA sequence is 2892 bp long, with a 2508 bp open reading frame that encodes an 835-amino acid polypeptide. Multiple alignment revealed that cgMTF has four putative zinc finger-like regions in cgMTF with three C2C2-type zinc fingers and one C2H2-type zinc finger. After 12 h of exposure to Cd(2+), the cgMTF mRNA level was increased in a dose-dependent manner, which then subsided with time. cgMTF stimulates the cgMT promoter reporter in the HEK293 cell line in a dose-dependent manner. When either of the metal-responsive elements (MRE1 or MRE2) of the cgMT promoter was mutated, the cgMT promoter reporter activity was significantly reduced. After the two MREs were mutated simultaneously, the promoter activity was completely abolished. In conclusion, we identified an MTF in C. gigas and revealed the presence of an evolutionarily conserved molecular mechanism for coping with environmental metal stress.
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Affiliation(s)
- Jinrong Qiu
- South China Institute of Environmental Sciences, MEP, Guangzhou 510655, China
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34
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Krześlak A, Forma E, Chwatko G, Jóźwiak P, Szymczyk A, Wilkosz J, Różański W, Bryś M. Effect of metallothionein 2A gene polymorphism on allele-specific gene expression and metal content in prostate cancer. Toxicol Appl Pharmacol 2013; 268:278-85. [PMID: 23466427 DOI: 10.1016/j.taap.2013.02.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 02/18/2013] [Accepted: 02/22/2013] [Indexed: 12/13/2022]
Abstract
Metallothioneins (MTs) are highly conserved, small molecular weight, cysteine rich proteins. The major physiological functions of metallothioneins include homeostasis of essential metals Zn and Cu and protection against cytotoxicity of heavy metals. The aim of this study was to determine whether there is an association between the -5 A/G single nucleotide polymorphism (SNP; rs28366003) in core promoter region and expression of metallothionein 2A (MT2A) gene and metal concentration in prostate cancer tissues. MT2A polymorphism was determined by the polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP) using 412 prostate cancer tissue samples. MT2A gene expression analysis was performed by real-time RT-PCR method. A significant association between rs28366003 genotype and MT2A expression level was found. The average mRNA level was found to be lower among minor allele carriers (the risk allele) than average expression among homozygotes for the major allele. Metal levels were analyzed by flamed atomic absorption spectrometer system. Highly statistically significant associations were detected between the SNP and Cd, Zn, Cu and Pb levels. The results of Spearman's rank correlation showed that the expressions of MT2A and Cu, Pb and Ni concentrations were negatively correlated. On the basis of the results obtained in this study, we suggest that SNP polymorphism may affect the MT2A gene expression in prostate and this is associated with some metal accumulation.
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Affiliation(s)
- Anna Krześlak
- Department of Cytobiochemistry, University of Łódź, Pomorska 141/143, 90-236 Łódź, Poland
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35
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Tang S, Allagadda V, Chibli H, Nadeau JL, Mayer GD. Comparison of cytotoxicity and expression of metal regulatory genes in zebrafish (Danio rerio) liver cells exposed to cadmium sulfate, zinc sulfate and quantum dots. Metallomics 2013; 5:1411-22. [DOI: 10.1039/c3mt20234h] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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36
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Jeong J, Walker JM, Wang F, Park JG, Palmer AE, Giunta C, Rohrbach M, Steinmann B, Eide DJ. Promotion of vesicular zinc efflux by ZIP13 and its implications for spondylocheiro dysplastic Ehlers-Danlos syndrome. Proc Natl Acad Sci U S A 2012; 109:E3530-8. [PMID: 23213233 PMCID: PMC3529093 DOI: 10.1073/pnas.1211775110] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Zinc is essential but potentially toxic, so intracellular zinc levels are tightly controlled. A key strategy used by many organisms to buffer cytosolic zinc is to store it within vesicles and organelles.It is yet unknown whether vesicular or organellar sites perform this function in mammals. Human ZIP13, a member of the Zrt/Irt-like protein (ZIP) metal transporter family, might provide an answer to this question. Mutations in the ZIP13 gene, SLC39A13, previously were found to cause the spondylocheiro dysplastic form of Ehlers–Danlos syndrome (SCD-EDS), a heritable connective tissue disorder.Those previous studies suggested that ZIP13 transports excess zinc out of the early secretory pathway and that zinc overload in the endoplasmic reticulum (ER) occurs in SCD-EDS patients. In contrast,this study indicates that ZIP13’s role is to release labile zinc from vesicular stores for use in the ER and other compartments. We propose that SCD-EDS is the result of vesicular zinc trapping and ER zinc deficiency rather than overload.
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Affiliation(s)
- Jeeyon Jeong
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
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37
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Sims HI, Chirn GW, Marr MT. Single nucleotide in the MTF-1 binding site can determine metal-specific transcription activation. Proc Natl Acad Sci U S A 2012; 109:16516-21. [PMID: 23012419 PMCID: PMC3478646 DOI: 10.1073/pnas.1207737109] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells respond to changes in environment by shifting their gene expression profile to deal with the new conditions. The cellular response to changes in metal homeostasis is an important example of this. Transition metals such as iron, zinc, and copper are essential micronutrients but other metals such as cadmium are simply toxic. The cell must maintain metal concentrations in a window that supports efficient metabolic function but must also protect against the damaging effects of high concentrations of these metals. One way a cell regulates metal homeostasis is to control genes involved in metal mobilization and storage. Much of this regulation occurs at the level of transcription and the protein most responsible for this is the conserved metal responsive transcription factor 1 (MTF-1). Interestingly, the nature of the changes in the gene expression profile depends on the type of exposure. The cell somehow senses the kind of the metal challenge and responds appropriately. We have been using the Drosophila system to try to understand the mechanism of this metal discrimination. Using genome-wide mapping of MTF-1 binding under different metal stresses we find that, surprisingly, MTF-1 chooses different DNA binding sites depending on the specific nature of the metal insult. We also find that the type of binding site chosen is an important component of the capability to induce the metal-specific transcription activation.
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Affiliation(s)
- Hillel I. Sims
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Gung-Wei Chirn
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Michael T. Marr
- Department of Biology, Brandeis University, Waltham, MA 02454
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38
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Determination of bioavailable-zinc from biofortified wheat using a coupled in vitro digestion/Caco-2 reporter-gene based assay. J Food Compost Anal 2012. [DOI: 10.1016/j.jfca.2011.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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39
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Apolipoprotein E genotype affects tissue metallothionein levels: studies in targeted gene replacement mice. GENES AND NUTRITION 2012; 7:247-55. [PMID: 22328270 DOI: 10.1007/s12263-012-0282-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 01/24/2012] [Indexed: 12/14/2022]
Abstract
The apolipoprotein E (APOE) genotype is an important risk factor for ageing and age-related diseases. The APOE4 genotype (in contrast to APOE3) has been shown to be associated with oxidative stress and chronic inflammation. Metallothioneins (MT) exhibit antioxidant and anti-inflammatory activity, and MT overexpression has been shown to increase lifespan in mice. Interactions between APOE and MT, however, are largely unknown. Hence, we determined the effect of the APOE4 versus APOE3 genotype on MT levels in targeted gene replacement mice. APOE4 versus APOE3 mice exhibited significantly lower hepatic MT1 and MT2 mRNA as well as lower MT protein levels. The decrease in hepatic MT protein levels in APOE4 as compared to APOE3 mice was accompanied by lower nuclear Nrf1, a protein partly controlling MT gene expression. Cell culture experiments using hepatocytes identified allyl-isothiocyanate (AITC) as a potent MT inductor in vitro. Therefore, we supplemented APOE3 and APOE4 mice with AITC. However, AITC (15 mg/kg b.w.) could only partly correct for decreased MT1 and MT2 gene expression in APOE4 mice in vivo. Furthermore, cholesterol significantly decreased both Nrf1 and MT mRNA levels in Huh7 cells indicating that differences in MT gene expression between the two genotypes could be related to differences in hepatic cholesterol concentrations. Overall, present data suggest that the APOE genotype is an important determinant of tissue MT levels in mice and that MT gene expression may be impaired by the APOE4 genotype.
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Dubé A, Harrisson JF, Saint-Gelais G, Séguin C. Hypoxia acts through multiple signaling pathways to induce metallothionein transactivation by the metal-responsive transcription factor-1 (MTF-1). Biochem Cell Biol 2011; 89:562-77. [PMID: 22087877 PMCID: PMC4020849 DOI: 10.1139/o11-063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Metal-responsive transcription factor-1 (MTF-1) is essential for the induction of genes encoding metallothionein by metals and hypoxia. Here, we studied the mechanism controlling the activation of MTF-1 by hypoxia. Hypoxia activation of Mt gene transcription is dependent on the presence of metal regulatory elements (MREs) in the promoter of Mt genes. We showed that MREa and MREd are the main elements controlling mouse Mt-1 gene induction by hypoxia. Transfection experiments in Mtf-1-null cells showed that MTF-1 is essential for induction by hypoxia. Chromatin immunoprecipitation analysis showed that MTF-1 DNA-binding activity was strongly enhanced in the presence of zinc but not by hypoxia. Notably, hypoxia inducible factor- (HIF) 1α was recruited to the Mt-1 promoter in response to hypoxia but not to zinc. MTF-1 activation was inhibited by PKC, JNK, and PI3K inhibitors and by the electron transport chain inhibitors rotenone and myxothiazol, but not by the antioxidant N-acetylcysteine. We showed that prolyl-hydroxylase inhibitors can activate MTF-1, but this activation requires the presence of HIF-1α. Finally, HIF-dependent transcription is enhanced in the presence of MTF-1 and induction of an MRE promoter is stimulated by HIF-1α, thus indicating cooperation between these 2 factors. However, coimmunoprecipitation experiments did not suggest direct interaction between MTF-1 and HIF-1α.
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Affiliation(s)
- Annie Dubé
- Centre de recherche en cancérologie de l'Université Laval, CHUQ, Hôtel-Dieu de QC, 9, rue McMahon, QC G1R 2J6, Canada
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Mammalian metallothionein in toxicology, cancer, and cancer chemotherapy. J Biol Inorg Chem 2011; 16:1087-101. [PMID: 21822976 DOI: 10.1007/s00775-011-0823-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/20/2011] [Indexed: 12/16/2022]
Abstract
The present paper centers on mammalian metallothionein 1 and 2 in relationship to cell and tissue injury beginning with its reaction with Cd²⁺ and then considering its role in the toxicology and chemotherapy of both metals and non-metal electrophiles and oxidants. Intertwined is a consideration of MTs role in tumor cell Zn²⁺ metabolism. The paper updates and expands on our recent review by Petering et al. (Met Ions Life Sci 5:353-398, 2009).
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Gupta RS, Ahnn J. Cadmium‐induced gene expression is regulated by MTF‐1, a key metal‐responsive transcription factor. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/12265071.2003.9647702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Ronojoy Sen Gupta
- a Department of Life Science and Biotechnology , Jadavpur University , Calcutta , 700032 , India Phone: E-mail:
| | - Joohong Ahnn
- b Department of Life Science , Kwangju Institute of Science and Technology , Gwangju , 500–712 , Korea
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Cheung APL, Au CYM, Chan WWL, Chan KM. Characterization and localization of metal-responsive-element-binding transcription factors from tilapia. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:42-55. [PMID: 20427094 DOI: 10.1016/j.aquatox.2010.03.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 03/26/2010] [Accepted: 03/30/2010] [Indexed: 05/29/2023]
Abstract
Two isoforms of MTF-1, MTF-1L (long form) and MTF-1S (short form), were cloned in tilapia (Ti) and characterized in a tilapia liver cell line, Hepa-T1. The cloned tiMTF-1L has the characteristics of all of the tiMTF-1S identified so far with the zinc finger domain having six fingers, the acidic-rich, proline-rich, and serine/threonine-rich domains; however, the short form encodes for the zinc finger domain with five zinc fingers only and no other domains. The transient transfection of tiMTF-1L into human HepG2 cells showed both constitutive and zinc-induced metal-responsive-element (MRE)-driven reporter gene expression. However, the transfection of tiMTF-1S (which lacks all three transactivation domains) into a human cell line showed reduced transcriptional activities compared with an endogenous control in both basal- and Zn(2+)-induced conditions. The tiMTF-1 isoforms were tagged with GFP and transfected into Hepa-T1 cells (tilapia hepatocytes). The nuclear translocation of tiMTF-1L was observed when the cells were exposed to a sufficient concentration of metals for 6h. However, tiMTF-1S, was localized in the nucleus with or without metal treatment. Electrophoretic mobility shift assay (EMSA) confirmed that both of the isoforms were able to bind to the MRE specifically in vitro. Tissue distribution studies showed that tiMTF-1L was more abundant than tiMTF-1S in all of the tissues tested.
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Affiliation(s)
- Andrew Pok-Lap Cheung
- Department of Biochemistry, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong, China
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Role of metallothionein in cadmium traffic and toxicity in kidneys and other mammalian organs. Biometals 2010; 23:897-926. [PMID: 20549307 DOI: 10.1007/s10534-010-9351-z] [Citation(s) in RCA: 191] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 05/28/2010] [Indexed: 12/11/2022]
Abstract
Metallothioneins are cysteine-rich, small metal-binding proteins present in various mammalian tissues. Of the four common metallothioneins, MT-1 and MT-2 (MTs) are expressed in most tissues, MT-3 is predominantly present in brain, whereas MT-4 is restricted to the squamous epithelia. The expression of MT-1 and MT-2 in some organs exhibits sex, age, and strain differences, and inducibility with a variety of stimuli. In adult mammals, MTs have been localized largely in the cell cytoplasm, but also in lysosomes, mitochondria and nuclei. The major physiological functions of MTs include homeostasis of essential metals Zn and Cu, protection against cytotoxicity of Cd and other toxic metals, and scavenging free radicals generated in oxidative stress. The role of MTs in Cd-induced acute and chronic toxicity, particularly in liver and kidneys, is reviewed in more details. In acute toxicity, liver is the primary target, whereas in chronic toxicity, kidneys are major targets of Cd. The intracellular MTs bind Cd ions and form CdMT. In chronic intoxication, Cd stimulates de novo synthesis of MTs; it is assumed that toxicity in the cells starts when loading with Cd ions exceeds the buffering capacity of intracellular MTs. CdMT, released from the Cd-injured organs, or when applied parenterally for experimental purposes, reaches the kidneys via circulation, where it is filtered, endocytosed in the proximal tubule cells, and degraded in lysosomes. Liberated Cd can immediately affect the cell structures and functions. The resulting proteinuria and CdMT in the urine can be used as biomarkers of tubular injury.
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Kothinti R, Blodgett A, Tabatabai NM, Petering DH. Zinc finger transcription factor Zn3-Sp1 reactions with Cd2+. Chem Res Toxicol 2010; 23:405-12. [PMID: 20073493 DOI: 10.1021/tx900370u] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cadmium is a major environmental pollutant that causes kidney failure including the inability to resorb nutrients such as glucose. In a mouse kidney cell culture model, Cd(2+) inhibits Na(+)-dependent glucose uptake mediated by SGLT transporters. This defect has been traced to the down-regulation of SGLT mRNA synthesis mediated by the zinc-finger transcription factor, Zn(3)-Sp1. Incubation of Cd(2+) with Zn(2+)-Sp1 inhibited its capacity to bind to GC1, its binding site in the SGLT1 promoter. The extent of reaction was reduced as increasing concentrations of Zn(2+) are simultaneously present in the reaction mixture. The results are consistent with a Cd(2+)-Zn(2+) exchange reaction that inactivates the DNA binding function of the protein. The equilibrium constant for this reaction was calculated as 14 +/- 3 and 7 +/- 4 for the reactions measured by the binding to GC1 and an analogous SGLT2 promoter site. Sequential addition of Cd(2+) and Zn(2+) to Zn(3)-Sp1 failed to inhibit the reduction in DNA binding seen with Cd(2+) alone, indicating that substitution of Zn(2+) by Cd(2+) was followed by a second reaction that failed to respond to Zn(2+). Buffers for the DNA binding reaction (electrophoretic mobility shift assay) contain EDTA and Cd-EDTA is active in the same concentration range as Cd(2+). During the standard 15 min incubation, Cd(2+) down-regulates Zn(3)-Sp1 but is inactive against the adduct, Zn(3)-Sp1.GC1. Kinetic studies demonstrated that with 5 muM Cd(2+), Zn(3)-Sp1 was about 75% inactivated in 15 min, whereas, Zn(3)-Sp1.GC1 was slowly dissociated with 50% still remaining after 60 min. In contrast, Zn(3)-Sp1 bound to a cognate consensus site resisted any reaction over 60 min. An adduct of Zn(3)-Sp1.(polydI-dC) was just as reactive with Cd(2+) as Zn(3)-Sp1. Reexamination of the NMR structure of Zn- and Cd-finger peptides related to Sp1 fingers has revealed subtle changes in conformation of the metalbinding site and DNA-binding helix that occur when Cd(2+) is substituted by Zn(2+).
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Affiliation(s)
- Rajendra Kothinti
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
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Balesaria S, Ramesh B, McArdle H, Bayele HK, Srai SKS. Divalent metal-dependent regulation of hepcidin expression by MTF-1. FEBS Lett 2010; 584:719-25. [PMID: 20026331 DOI: 10.1016/j.febslet.2009.12.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 12/11/2009] [Accepted: 12/15/2009] [Indexed: 10/20/2022]
Abstract
Hepcidin is a small acute phase peptide that regulates iron absorption. It is induced by inflammation and infection, but is repressed by anaemia and hypoxia. Here we further reveal that hepcidin transcription also involves interactions between functional metal response elements (MREs) in its promoter, and the MRE-binding transcription factor-1. Analysis of hepcidin mRNA and protein levels in hepatoma cells suggests that its expression may be regulated by divalent metal ions, with zinc inducing maximal effects on hepcidin levels. These data suggest that this peptide may be a pleiotropic sensor of divalent metals, some of which are xenobiotic environmental toxins.
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Affiliation(s)
- Sara Balesaria
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom.
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Kimura T. Molecular Mechanisms of Zinc-mediated Induction and Chromium(VI)-mediated Inhibition of Mouse Metallothionein-I Gene Transcription. ACTA ACUST UNITED AC 2010. [DOI: 10.1248/jhs.56.161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Tomoki Kimura
- Department of Toxicology, Faculty of Pharmaceutical Sciences, Setsunan University
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Cortese-Krott MM, Münchow M, Pirev E, Hessner F, Bozkurt A, Uciechowski P, Pallua N, Kröncke KD, Suschek CV. Silver ions induce oxidative stress and intracellular zinc release in human skin fibroblasts. Free Radic Biol Med 2009; 47:1570-7. [PMID: 19733233 DOI: 10.1016/j.freeradbiomed.2009.08.023] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 08/05/2009] [Accepted: 08/28/2009] [Indexed: 12/19/2022]
Abstract
Silver compounds used as topical antimicrobial agents are known to exert toxic effects on skin cells. The aim of this study was to investigate whether the toxicity of silver ions, in analogy to other transition metal ions, depends on pro-oxidant effects. We treated human skin fibroblasts with concentrations of AgNO(3) not affecting cell proliferation, mitochondrial activity, or cell viability and found that Ag(+) strongly increases the production of reactive oxygen species, including superoxide anion radicals. These effects correspond to a strong decrease in intracellular reduced glutathione and to an increased susceptibility to H(2)O(2)-induced cell death. In addition, AgNO(3) down-regulates the expression of antioxidant genes such as the transcription factor Nrf2 and its target gene glutamate-cysteine ligase catalytic subunit. Furthermore Ag(+) induces a transient intracellular zinc release and increases the mRNA and protein expression of the zinc-binding protein metallothionein by activating the metal-responsive transcription factor 1, as verified by RNA interference. In conclusion, we show for the first time that Ag(+) induces oxidative stress and affects intracellular zinc homeostasis in human skin fibroblasts. The understanding of the mechanism involved in silver toxicity might contribute to new strategies for managing the therapy of skin infections.
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Affiliation(s)
- Miriam M Cortese-Krott
- Department of Internal Medicine B, Cardiovascular Research Laboratory, Medical Faculty of the Heinrich-Heine-University Düsseldorf, D-40225 Düsseldorf, Germany.
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Nemec AA, Leikauf GD, Pitt BR, Wasserloos KJ, Barchowsky A. Nickel mobilizes intracellular zinc to induce metallothionein in human airway epithelial cells. Am J Respir Cell Mol Biol 2009; 41:69-75. [PMID: 19097988 PMCID: PMC2701961 DOI: 10.1165/rcmb.2008-0409oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 12/02/2008] [Indexed: 11/24/2022] Open
Abstract
We recently reported that induction of metallothionein (MT) was critical in limiting nickel (Ni)-induced lung injury in intact mice. Nonetheless, the mechanism by which Ni induces MT expression is unclear. We hypothesized that the ability of Ni to mobilize zinc (Zn) may contribute to such regulation and therefore, we examined the mechanism for Ni-induced MT2A expression in human airway epithelial (BEAS-2B) cells. Ni induced MT2A transcript levels and protein expression by 4 hours. Ni also increased the activity of a metal response element (MRE) promoter luciferase reporter construct, suggesting that Ni induces MRE binding of the metal transcription factor (MTF-1). Exposure to Ni resulted in the nuclear translocation of MTF-1, and Ni failed to induce MT in mouse embryonic fibroblasts lacking MTF-1. As Zn is the only metal known to directly bind MTF-1, we then showed that Ni increased a labile pool of intracellular Zn in cells as revealed by fluorescence-activated cell sorter using the Zn-sensitive fluorophore, FluoZin-3. Ni-induced increases in MT2A mRNA and MRE-luciferase activity were sensitive to the Zn chelator, TPEN, supporting an important role for Zn in mediating the effect of Ni. Although neither the source of labile Zn nor the mechanism by which Ni liberates labile Zn was apparent, it was noteworthy that Ni increased intracellular reactive oxygen species (ROS). Although both N-acetyl cysteine (NAC) and ascorbic acid (AA) decreased Ni-induced increases in ROS, only NAC prevented Ni-induced increases in MT2A mRNA, suggesting a special role for interactions of Ni, thiols, and Zn release.
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Affiliation(s)
- Antonia A Nemec
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
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Petering DH, Krezoski S, Tabatabai NM. Metallothionein Toxicology: Metal Ion Trafficking and Cellular Protection. METALLOTHIONEINS AND RELATED CHELATORS 2009. [DOI: 10.1039/9781847559531-00353] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The literature is replete with reports about the involvement of metallothionein in host defense against injurious chemical, biological, and physical agents. Yet, metallothionein's functional roles are still being debated. This review addresses the issues that have left the physiological significance of metallothionein in doubt and moves on to assess the MT's importance in cell toxicology. It is evident that the protein is broadly involved in protecting cells from injury due to toxic metal ions, oxidants, and electrophiles. Attention is focused on MT's structural and chemical properties that confer this widespread role in cell protection. Particular emphasis is placed on the implications of finding that metal ion unsaturated metallothionein is commonly present in many cells and tissues and the question, how does selectivity of reaction with metallothionein take place in the cellular environment that includes large numbers of competing metal binding sites and high concentrations of protein and glutathione sulfhydryl groups?
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Affiliation(s)
- David H. Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee Milwaukee WI 53201 USA
| | - Susan Krezoski
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee Milwaukee WI 53201 USA
| | - Niloofar M. Tabatabai
- Division of Endocrinology, Metabolism and Clinical Nutrition and Kidney Disease Center Medical College of Wisconsin Milwaukee WI 53226 USA
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