1
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Zhang C, Dischler A, Glover K, Qin Y. Neuronal signalling of zinc: from detection and modulation to function. Open Biol 2022; 12:220188. [PMID: 36067793 PMCID: PMC9448499 DOI: 10.1098/rsob.220188] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Zinc is an essential trace element that stabilizes protein structures and allosterically modulates a plethora of enzymes, ion channels and neurotransmitter receptors. Labile zinc (Zn2+) acts as an intracellular and intercellular signalling molecule in response to various stimuli, which is especially important in the central nervous system. Zincergic neurons, characterized by Zn2+ deposits in synaptic vesicles and presynaptic Zn2+ release, are found in the cortex, hippocampus, amygdala, olfactory bulb and spinal cord. To provide an overview of synaptic Zn2+ and intracellular Zn2+ signalling in neurons, the present paper summarizes the fluorescent sensors used to detect Zn2+ signals, the cellular mechanisms regulating the generation and buffering of Zn2+ signals, as well as the current perspectives on their pleiotropic effects on phosphorylation signalling, synapse formation, synaptic plasticity, as well as sensory and cognitive function.
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Affiliation(s)
- Chen Zhang
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Anna Dischler
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Kaitlyn Glover
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Yan Qin
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
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2
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Morgan ML, Teo W, Hernandez Y, Brideau C, Cummins K, Kuipers HF, Stys PK. Cuprizone-induced Demyelination in Mouse Brain is not due to Depletion of Copper. ASN Neuro 2022; 14:17590914221126367. [PMID: 36114624 PMCID: PMC9483969 DOI: 10.1177/17590914221126367] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The cuprizone (CPZ) model allows the study of the biochemical processes underlying
nonautoimmune-mediated demyelination, remyelination, and chronic white matter disease
progression. CPZ is a copper (Cu) chelator that chiefly causes oligodendrocyte apoptosis
in the corpus callosum and cerebellum when administered in the mouse diet. While
disruption of Cu homeostasis is known to cause neurodegeneration (as is observed in
Wilson’s and Menkes disease), no consensus exists to date as to CPZ’s mechanism of action.
We sought to determine whether CPZ-induced pathology is due to Cu depletion as is
generally believed. Cu supplementation in chow, in stoichiometric excess to the added CPZ,
did not reduce CPZ-induced demyelination in C57Bl/6 mice. Moreover, equivalent doses of
other known Cu chelators neocuproine and D-penicillamine (D-Pen) failed to induce central
nervous system (CNS) demyelination. Since administration of D-Pen in the treatment of
Wilson’s disease can induce hypocupremia, we next sought to recreate penicillamine-induced
Cu deficiency to compare with purported CPZ-induced Cu deficiency. The resulting clinical
phenotype and histopathology were unlike that of CPZ. D-Pen-treated mice exhibited digit
paralysis, tail flaccidity, subcutaneous hemorrhaging, and optic and sciatic neuropathy,
all of which were prevented with Cu supplementation. No demyelination of the corpus
callosum or cerebellum was observed, even with D-Pen doses tenfold higher than CPZ.
Intriguingly, addition of D-Pen to the CPZ diet paradoxically prevented demyelination in a
dose-dependent manner.
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Affiliation(s)
- Megan L. Morgan
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
| | - Wulin Teo
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
| | - Yda Hernandez
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
| | - Craig Brideau
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
| | - Karen Cummins
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
| | - Hedwich F. Kuipers
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
| | - Peter K. Stys
- Cumming School of Medicine, Department of Clinical Neurosciences, University of Calgary, Hotchkiss Brain Institute, Calgary, 3330 Hospital Drive N.W. HRIC 1B37A, Calgary, AB, T2N 4N1, Canada
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Sullivan B, Robison G, Osborn J, Kay M, Thompson P, Davis K, Zakharova T, Antipova O, Pushkar Y. On the nature of the Cu-rich aggregates in brain astrocytes. Redox Biol 2017; 11:231-239. [PMID: 28012438 PMCID: PMC5198742 DOI: 10.1016/j.redox.2016.12.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/04/2016] [Accepted: 12/02/2016] [Indexed: 01/15/2023] Open
Abstract
Fulfilling a bevy of biological roles, copper is an essential metal for healthy brain function. Cu dyshomeostasis has been demonstrated to be involved in some neurological conditions including Menkes and Alzheimer's diseases. We have previously reported localized Cu-rich aggregates in astrocytes of the subventricular zone (SVZ) in rodent brains with Cu concentrations in the hundreds of millimolar. Metallothionein, a cysteine-rich protein critical to metal homeostasis and known to participate in a variety of neuroprotective and neuroregenerative processes, was proposed as a binding protein. Here, we present an analysis of metallothionein(1,2) knockout (MTKO) mice and age-matched controls using X-ray fluorescence microscopy. In large structures such as the corpus callosum, cortex, and striatum, there is no significant difference in Cu, Fe, or Zn concentrations in MTKO mice compared to age-matched controls. In the astrocyte-rich subventricular zone where Cu-rich aggregates reside, approximately 1/3 as many Cu-rich aggregates persist in MTKO mice resulting in a decrease in periventricular Cu concentration. Aggregates in both wild-type and MTKO mice show XANES spectra characteristic of CuxSy multimetallic clusters and have similar [S]/[Cu] ratios. Consistent with assignment as a CuxSy multimetallic cluster, the astrocyte-rich SVZ of both MTKO and wild-type mice exhibit autofluorescent bodies, though MTKO mice exhibit fewer. Furthermore, XRF imaging of Au-labeled lysosomes and ubiquitin demonstrates a lack of co-localization with Cu-rich aggregates suggesting they are not involved in a degradation pathway. Overall, these data suggest that Cu in aggregates is bound by either metallothionein-3 or a yet unknown protein similar to metallothionein.
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Affiliation(s)
- Brendan Sullivan
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Gregory Robison
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Jenna Osborn
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Martin Kay
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Peter Thompson
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Katherine Davis
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Taisiya Zakharova
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Olga Antipova
- BioCAT, Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439, United States; XSD, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439, United States
| | - Yulia Pushkar
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States.
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Dziegiel P, Pula B, Kobierzycki C, Stasiolek M, Podhorska-Okolow M. The Role of Metallothioneins in Carcinogenesis. ADVANCES IN ANATOMY EMBRYOLOGY AND CELL BIOLOGY 2016. [DOI: 10.1007/978-3-319-27472-0_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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5
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Metallothioneins and brain injury: What transgenic mice tell us. Environ Health Prev Med 2012; 9:87-94. [PMID: 21432316 DOI: 10.1007/bf02898066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2004] [Accepted: 03/18/2004] [Indexed: 10/21/2022] Open
Abstract
In rodents, the metallothionein (MT) family is composed of four members, MT-1 to MT-4. MT-1&2 are expressed in virtually all tissues including those of the Central Nervous System (CNS), while MT-3 (also called Growth Inhibitory Factor) and MT-4 are expressed prominently in the brain and in keratinizing epithelia, respectively. For the understanding of the physiological functions of these proteins in the brain, the use of transgenic mice has provided essential information. Results obtained inMT-1&2-null mice and in MT-1-overexpressing mice strongly suggeset that these MT isoforms are important antioxidant, anti-inflammatory and antiapoptotic proteins in the brain. Results inMT-3-null mice show a very different pattern, with no support for MT-1&2-like functions. Rather, MT-3 could be involved in neuronal sprouting and survival. Results obtained in a model of peripheral nervous system injury also suggest that MT-3 could be involved in the control of nerve growth.
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Witherick J, Wilkins A, Scolding N, Kemp K. Mechanisms of oxidative damage in multiple sclerosis and a cell therapy approach to treatment. Autoimmune Dis 2010; 2011:164608. [PMID: 21197107 PMCID: PMC3010615 DOI: 10.4061/2011/164608] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 11/10/2010] [Indexed: 12/14/2022] Open
Abstract
Although significant advances have recently been made in the understanding and treatment of multiple sclerosis, reduction of long-term disability remains a key goal. Evidence suggests that inflammation and oxidative stress within the central nervous system are major causes of ongoing tissue damage in the disease. Invading inflammatory cells, as well as resident central nervous system cells, release a number of reactive oxygen and nitrogen species which cause demyelination and axonal destruction, the pathological hallmarks of multiple sclerosis. Reduction in oxidative damage is an important therapeutic strategy to slow or halt disease processes. Many drugs in clinical practice or currently in trial target this mechanism. Cell-based therapies offer an alternative source of antioxidant capability. Classically thought of as being important for myelin or cell replacement in multiple sclerosis, stem cells may, however, have a more important role as providers of supporting factors or direct attenuators of the disease. In this paper we focus on the antioxidant properties of mesenchymal stem cells and discuss their potential importance as a cell-based therapy for multiple sclerosis.
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Affiliation(s)
- Jonathan Witherick
- Multiple Sclerosis and Stem Cell Group, Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol BS16 1LE, UK
| | - Alastair Wilkins
- Multiple Sclerosis and Stem Cell Group, Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol BS16 1LE, UK
| | - Neil Scolding
- Multiple Sclerosis and Stem Cell Group, Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol BS16 1LE, UK
| | - Kevin Kemp
- Multiple Sclerosis and Stem Cell Group, Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol BS16 1LE, UK
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7
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Howells C, West AK, Chung RS. Neuronal growth-inhibitory factor (metallothionein-3): evaluation of the biological function of growth-inhibitory factor in the injured and neurodegenerative brain. FEBS J 2010; 277:2931-9. [PMID: 20561053 DOI: 10.1111/j.1742-4658.2010.07718.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuronal growth-inhibitory factor, later renamed metallothionein-3, is one of four members of the mammalian metallothionein family. Metallothioneins are a family of ubiquitous, low-molecular-weight, cysteine-rich proteins. Although neuronal growth-inhibitory factor shares metal-binding and reactive oxygen species scavenging properties with the other metallothioneins, it displays several distinct biological properties. In this review, we examine the recent developments regarding the function of neuronal growth-inhibitory factor within the brain, particularly in response to brain injury or during neurodegenerative disease progression.
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Affiliation(s)
- Claire Howells
- Menzies Research Institute, University of Tasmania, Hobart, Australia
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8
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Minami T, Miyata E, Sakamoto Y, Kohama A, Yamazaki H, Ichida S. Expression of metallothionein mRNAs on mouse cerebellum microglia cells by thimerosal and its metabolites. Toxicology 2009; 261:25-32. [PMID: 19386279 DOI: 10.1016/j.tox.2009.04.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 04/08/2009] [Accepted: 04/13/2009] [Indexed: 12/27/2022]
Abstract
Effects of thimerosal and its metabolites, ethyl mercury and thiosalicylate, on the expression of metallothionein (MT) mRNAs in mouse cerebellum microglia cell line, C8-B4 cells, were studied. The level of MT-1 mRNA significantly decreased at early hours and recovered time-dependently 24h after thimerosal was added to the C8-B4 cells. However, MT-2 and MT-3 mRNA expressions did not change from the control group. In contrast, the expression of MT-1 mRNA increased in a mouse neuroblastoma cell line 6h after incubation with thimerosal. In addition, the level of MT-1 mRNA decreased in C8-B4 cells 6h after the addition of thiosalicylate, but ethyl mercury induced MT-1 mRNA expression. When cell viability was compared with thimerosal, thiosalicylate, and ethyl mercury, the viability of C8-B4 cells decreased dose-dependently 24h after either thimerosal or ethyl mercury was added; however, the viability increased dose-dependently until 15 microM thiosalicylate was added. From the present results, it is concluded that the expression of MT-1 mRNA may be mediated by different factors than the expression of MT-2 mRNA in C8-B4 cells. The reduction of MT-1 mRNA level by thiosalicylate may affect the proliferation of C8-B4 cells.
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Affiliation(s)
- Takeshi Minami
- Department of Life Sciences, School of Science & Engineering, Kinki University, 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502, Japan.
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Xue W, Liu Q, Cai L, Wang Z, Feng W. Stable overexpression of human metallothionein-IIA in a heart-derived cell line confers oxidative protection. Toxicol Lett 2009; 188:70-6. [PMID: 19433272 DOI: 10.1016/j.toxlet.2009.03.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 03/06/2009] [Accepted: 03/09/2009] [Indexed: 11/19/2022]
Abstract
Metallothionein (MT) is a metal binding protein and cardioprotective. In order to understand the molecular mechanisms underlying the role of MT in the heart, in the current study we established a stable MT-IIA over-expressing cardiac cell line, and evaluated its anti-oxidative property. Rat heart-derived H9c2 cell line was stably transfected with a vector in which the human MT-IIA gene was placed under the control of the constitutively active beta-actin promoter. The transfected cell line (H9c2MT7) exhibited similar growth kinetics and morphology. Western blotting analysis showed that H9c2MT7 had a remarkable increased MT protein level compared with the parent cell line H9c2. Addition of 25 microM ZnSO(4) had an undetectable effect on the induction of endogenous MT, but it likely stabilized the MT protein that is expressed only in H9c2MT7 cells. H9c2MT7 cells showed marked reduction in reactive oxygen species production when exposed to hydrogen peroxide or subjected to hypoxia/reoxygenation challenge evaluated by dihydroethidium staining. In addition, transfection of MT conferred cellular resistance to cadmium toxicity. In summary, we have established a stable human MT-IIA over-expressing cardiac cell line; and this cell line showed a markedly increased oxidative protection and would be useful for dissection of the mechanisms of MT in the cardiac protection.
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Affiliation(s)
- Wanli Xue
- Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA
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10
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Ilbäck NG, Frisk P, Mohamed N, Gadhasson IL, Blomberg J, Friman G. Virus induces metal-binding proteins and changed trace element balance in the brain during the course of a common human infection (coxsackievirus B3) in mice. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 381:88-98. [PMID: 17467775 DOI: 10.1016/j.scitotenv.2007.03.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 03/13/2007] [Accepted: 03/15/2007] [Indexed: 05/15/2023]
Abstract
Autopsy of the brain has shown a change in trace element balance in some virus-infected individuals, but it is not known whether this event was a result of the infection. In the present study coxsackievirus B3 (CVB3) adapted to Balb/c mice was used to study whether infection induces gene expression of the metal-binding/transporting proteins metallothionein (MT1 and MT3) and divalent-metal transporter 1 (DMT1) and whether it changes the balance of trace elements in the brain. Virus and MT1, MT3, and DMT1 were quantitatively measured by RT-PCR on days 3, 6 and 9 of the infection. Trace elements (13) were measured in serum and the brain by ICP-MS. High numbers of virus were found in the brain on days 3 and 6, but virus counts were decreased and present only in 50% of the mice on day 9. Gene expression of MT1 tended to increase on all days, whereas that of MT3 only showed a minor and not significant increase on day 3. No clear effect was observed in the expression of DMT1. The increase of MT3 was correlated to the brain concentration of Cu. The Cu/Zn ratio in serum increased as a response to the infection. There was a similar decrease in Cd in serum and the brain. On day 6 of the infection, Hg increased in the brain (p<0.05) and was positively correlated to a concomitant decrease (p<0.05) in serum. Virus numbers in the brain were on day 6 positively correlated (p<0.05) to As concentrations. Enteroviral infections may therefore be an underlying factor regarding the changes in essential as well as potentially toxic trace elements in the brain.
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Affiliation(s)
- Nils-Gunnar Ilbäck
- Infectious Diseases, Department of Medical Sciences, Uppsala University Hospital, Sweden
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Abstract
This review summarises the role that reactive oxygen and nitrogen species play in demyelination, such as that occurring in the inflammatory demyelinating disorders multiple sclerosis and Guillain-Barré syndrome. The concentrations of reactive oxygen and nitrogen species (e.g. superoxide, nitric oxide and peroxynitrite) can increase dramatically under conditions such as inflammation, and this can overwhelm the inherent antioxidant defences within lesions. Such oxidative and/or nitrative stress can damage the lipids, proteins and nucleic acids of cells and mitochondria, potentially causing cell death. Oligodendrocytes are more sensitive to oxidative and nitrative stress in vitro than are astrocytes and microglia, seemingly due to a diminished capacity for antioxidant defence, and the presence of raised risk factors, including a high iron content. Oxidative and nitrative stress might therefore result in vivo in selective oligodendrocyte death, and thereby demyelination. The reactive species may also damage the myelin sheath, promoting its attack by macrophages. Damage can occur directly by lipid peroxidation, and indirectly by the activation of proteases and phospholipase A2. Evidence for the existence of oxidative and nitrative stress within inflammatory demyelinating lesions includes the presence of both lipid and protein peroxides, and nitrotyrosine (a marker for peroxynitrite formation). The neurological deficit resulting from experimental autoimmune demyelinating disease has generally been reduced by trial therapies intended to diminish the concentration of reactive oxygen species. However, therapies aimed at diminishing reactive nitrogen species have had a more variable outcome, sometimes exacerbating disease.
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Affiliation(s)
- K J Smith
- Department of Clinical Neurological Sciences, Guy's, King's and St. Thomas' School of Medicine, London.
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Barr GA, Gao P, Wang S, Cheng J, Qin J, Sibille EL, Pavlidis P. Microarray analysis of gene expression following the formalin test in the infant rat☆. Pain 2005; 117:6-18. [PMID: 16043289 DOI: 10.1016/j.pain.2005.04.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Revised: 03/28/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
Injury and pain experienced by the infant results in immediate changes in pain sensitivity that last into adulthood. These long-term changes are likely initiated by altered gene expression. Here we measured how injury alters gene expression in the lumbar spinal cord early and late in the preweaning period of the rat. The expression of large numbers of genes was altered significantly at 3 days of age, when injury has long-term consequences. The functional classes of altered genes included transcription factors, cell death related and metal ion genes. The intensity of the stimulus in the 3-day-old pups induced changes in different classes of genes. Fewer changes were noted at 21 days of age. The increased expression of transcription factors and decreased expression of genes whose products are protective against cell death are hypothesized to underlie the long-term changes that are seen after injury in the neonate.
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Affiliation(s)
- Gordon A Barr
- Department of Developmental Psychobiology, New York State Psychiatric Institute, New York, NY, USA.
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Wang J, Ma JH, Giffard RG. Overexpression of copper/zinc superoxide dismutase decreases ischemia-like astrocyte injury. Free Radic Biol Med 2005; 38:1112-8. [PMID: 15780769 DOI: 10.1016/j.freeradbiomed.2005.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 01/06/2005] [Accepted: 01/11/2005] [Indexed: 11/23/2022]
Abstract
Overexpression of copper/zinc superoxide dismutase (SOD1) in transgenic mice protects from transient focal cerebral ischemia in adult animals, but increases oxidative injury in perinatal mice. The effect of SOD1 overexpression on astrocytes subjected to ischemia-like insults has not yet been determined. Overexpression of human SOD1 in astrocytes resulted in a 3-fold increase in SOD1 activity without coupled up-regulation of catalase or glutathione peroxidase activities. Cells subjected to oxygen-glucose deprivation (OGD) or glucose deprivation to mimic ischemic injury were protected by SOD1 overexpression. OGD injury was reduced 47.6+/-9.3%, assessed by release of lactate dehydrogenase. OGD also caused a significant increase in catalase activity which was moderated by SOD1 overexpression. The level of glutathione in astrocytes overexpressing SOD1 was maintained at higher levels following 5 h OGD compared to control cultures under the same conditions. Reduction of glutathione prior to OGD significantly increased cell death of SOD1-overexpressing astrocytes as well as controls, but SOD1 still provided significant protection, suggesting that both GSH-dependent scavenging and GSH-independent scavenging are relevant to SOD1 protection in astrocytes.
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Affiliation(s)
- Jian Wang
- Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305, USA
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Dittmann J, Fung SJ, Vickers JC, Chuah MI, Chung RS, West AK. Metallothionein biology in the ageing and neurodegenerative brain. Neurotox Res 2005; 7:87-93. [PMID: 15639801 DOI: 10.1007/bf03033779] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In recent years metallothionein (MT) biology has moved from investigation of its ability to protect against environmental heavy metals to a wider appreciation of its role in responding to cellular stress, whether as a consequence of normal function, or following injury and disease. This is exemplified by recent investigation of MT in the mammalian brain where plausible roles for MT action have been described, including zinc metabolism, free radical scavenging, and protection and regeneration following neurological injury. Along with other laboratories we have used several models of central nervous system (CNS) injury to investigate possible parallels between injury-dependent changes in MT expression and those observed in the ageing and/or degenerating brain. Therefore, this brief review aims to summarise existing information on MT expression during CNS ageing, and to examine the possible involvement of this protein in the course of human neurodegenerative disease, as exemplified by Alzheimer's disease.
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Affiliation(s)
- J Dittmann
- NeuroRepair Group, School of Medicine, University of Tasmania, Tasmania 7001 Australia
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Ilbäck NG, Glynn AW, Wikberg L, Netzel E, Lindh U. Metallothionein is induced and trace element balance changed in target organs of a common viral infection. Toxicology 2004; 199:241-50. [PMID: 15147797 DOI: 10.1016/j.tox.2003.12.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2003] [Revised: 12/12/2003] [Accepted: 12/18/2003] [Indexed: 11/19/2022]
Abstract
In experimental studies on the common human coxsackievirus B type 3 (CB3) infection, administered cadmium (Cd) is known to accumulate in the liver and kidneys. CB3 adapted to Balb/c mice was used to study whether infection affects the Cd-binding protein, metallothionein (MT) and if this alters the normal physiological trace element balance in the liver, kidney, spleen and brain. On day 3 of infection, degradation of liver proteins (44%, P<0.01) occurred, whereas in the spleen, protein increased (63%, P<0.05). The infection increased MT five-fold (P<0.01) in liver and kidneys, and in spleen by 34% (P<0.05). A redistribution of Cd and copper (Cu) from the liver to the kidney was associated with this increase in MT, resulting in an increased (P<0.01) kidney/liver ratio for both elements. The infection increased the zinc (Zn) concentration more in the kidney than in the liver, but the kidney/liver ratio was not significantly affected. Results show that MT is increased in several organs during the early phase of infection and is associated with redistribution of both essential and non-essential trace elements. This may be a normal response in common infections that could adversely influence the pathogenesis when the host is concomitantly exposed to potentially toxic trace elements, even at levels in the physiological range.
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Affiliation(s)
- Nils-Gunnar Ilbäck
- Toxicology Division, Swedish National Food Administration, P.O. Box 622, Uppsala S-751 26, Sweden.
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Abstract
For many years, research focus on metallothioneins, small zinc binding proteins found predominantly within astrocytes in the brain, has centred on their ability to indirectly protect neurons from oxygen free radicals and heavy metal-induced neurotoxicity. However, in recent years it has been demonstrated that these proteins have previously unsuspected roles within the cellular response to brain injury. The aim of this commentary is to provide an overview of the exciting recent experimental evidence from several laboratories including our own suggesting a possible extracellular role for these proteins, and to present a hypothetical model explaining the newly identified function of extracellular metallothioneins in CNS injury and repair.
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Affiliation(s)
- R S Chung
- NeuroRepair Group, School of Medicine, University of Tasmania, Private Bag 58, Tasmania 7001, Hobart, Australia.
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17
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HIDALGO J. Metallothioneins and Brain Injury: What Transgenic Mice Tell Us. Environ Health Prev Med 2004. [DOI: 10.1265/ehpm.9.87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Carrasco J, Penkowa M, Giralt M, Camats J, Molinero A, Campbell IL, Palmiter RD, Hidalgo J. Role of metallothionein-III following central nervous system damage. Neurobiol Dis 2003; 13:22-36. [PMID: 12758064 DOI: 10.1016/s0969-9961(03)00015-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We evaluated the physiological relevance of metallothionein-III (MT-III) in the central nervous system following damage caused by a focal cryolesion onto the cortex by studying Mt3-null mice. In normal mice, dramatic astrogliosis and microgliosis and T-cell infiltration were observed in the area surrounding the lesioned tissue, along with signs of increased oxidative stress and apoptosis. There was also significant upregulation of cytokines/growth factors such as tumor necrosis factor-alpha, interleukin (IL)-1 alpha/beta, and IL-6 as measured by ribonuclease protection assay. Mt3-null mice did not differ from control mice in these responses, in sharp contrast to results obtained in Mt1- Mt2-null mice. In contrast, Mt3-null mice showed increased expression of several neurotrophins as well as of the neuronal sprouting factor GAP-43. Thus, unlike MT-I and MT-II, MT-III does not affect the inflammatory response elicited in the central nervous system by a cryoinjury, nor does it serve an important antioxidant role, but it may influence neuronal regeneration during the recovery process.
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Affiliation(s)
- Javier Carrasco
- Institute of Neurosciences and Department of Cellular Biology, Physiology and Immunology, Animal Physiology Unit, Faculty of Sciences, Autonomous University of Barcelona, Bellaterra, Barcelona, Spain 08193
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Hidalgo J, Penkowa M, Giralt M, Carrasco J, Molinero A. Metallothionein expression and oxidative stress in the brain. Methods Enzymol 2002; 348:238-49. [PMID: 11885277 DOI: 10.1016/s0076-6879(02)48642-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Juan Hidalgo
- Department of Cellular Biology, Physiology, and Immunology, Animal Physiology Unit, Autonomous University of Barcelona, 08193 Barcelona, Spain
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Cherian MG, Suzuki Y, Apostolova M. Mouse astrocyte cultures used to study antioxidant property of metallothionein isoforms. Methods Enzymol 2002; 348:337-42. [PMID: 11885288 DOI: 10.1016/s0076-6879(02)48652-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- M George Cherian
- Department of Pathology, University of Western Ontario, London, Ontario, Canada N6A 5C1
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Hidalgo J, Aschner M, Zatta P, Vasák M. Roles of the metallothionein family of proteins in the central nervous system. Brain Res Bull 2001; 55:133-45. [PMID: 11470309 DOI: 10.1016/s0361-9230(01)00452-x] [Citation(s) in RCA: 309] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Metallothioneins (MTs) constitute a family of proteins characterized by a high heavy metal [Zn(II), Cu(I)] content and also by an unusual cysteine abundance. Mammalian MTs are comprised of four major isoforms designated MT-1 trough MT-4. MT-1 and MT-2 are expressed in most tissues including the brain, whereas MT-3 (also called growth inhibitory factor) and MT-4 are expressed predominantly in the central nervous system and in keratinizing epithelia, respectively. All MT isoforms have been implicated in disparate physiological functions, such as zinc and copper metabolism, protection against reactive oxygen species, or adaptation to stress. In the case of MT-3, an additional involvement of this isoform in neuromodulatory events and in the pathogenesis of Alzheimer's disease has also been suggested. It is essential to gain insight into how MTs are regulated in the brain in order to characterize MT functions, both in normal brain physiology, as well as in pathophysiological states. The focus of this review concerns the biology of the MT family in the context of their expression and functional roles in the central nervous system.
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Affiliation(s)
- J Hidalgo
- Department of Cellular Biology, Physiology and Immunology, Animal Physiology Unit, Faculty of Sciences, Autonomous University of Barcelona, Bellaterra, Barcelona, Spain.
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Abstract
Overexpression of Cu,Zn SOD (SOD1) can increase survival of neurons under some pathological conditions. Prior studies have shown, however, that SOD1 overexpression can reduce neuronal survival during exposure to superoxide generators by a mechanism involving excess H(2)O(2) accumulation. Since astrocytes exhibit greater H(2)O(2) catabolism capacity than do neurons, the present study examined the effects of SOD1 overexpression on astrocyte survival under these conditions. Cultures were prepared from transgenic mice that overexpress human SOD1 and from nontransgenic littermate controls. Exposure to xanthine oxidase/hypoxanthine (XO/HPX) or menadione caused dose-dependent astrocyte death. In contrast to prior observations with neurons, astrocytes that overexpress SOD1 showed increased resistance to superoxide toxicity. Surprisingly, increased survival in SOD1 overexpressing cultures remained evident even when H(2)O(2) catabolism was inhibited by preincubation with aminotriazole (to block catalase) and buthionine sulfoximine (to deplete glutathione). These findings suggest differences in superoxide metabolism between neurons and astrocytes, and that the greater resistance of astrocytes to oxidative stress is due at least partly to factors other than greater glutathione peroxidase and catalase activity in astrocytes. GLIA 33:343-347, 2001. Published 2001 Wiley-Liss, Inc.
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Affiliation(s)
- Y Chen
- Department of Neurology, University of California and Veterans Affairs Medical Center, San Francisco, CA 94121, USA
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Pentreath VW, Slamon ND. Astrocyte phenotype and prevention against oxidative damage in neurotoxicity. Hum Exp Toxicol 2000; 19:641-9. [PMID: 11211243 DOI: 10.1191/096032700676221595] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Astrocytes possess a potent array of protective systems. These are chiefly targeted against oxidised products and radicals, which are frequently present in increased amounts following exposure of nervous tissue to a range of toxic insults. Following exposure to the toxic chemicals astrocytes commonly respond by alteration in phenotype with upregulation of a large number of molecules, including those controlling the protective systems. This article summarizes evidence, largely obtained from in vitro studies, which supports the concept that some of the changes in astrocyte phenotype are associated with increased protection against the cytotoxicity caused by the oxidative damage that results from exposure to range of neurotoxicants.
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Affiliation(s)
- V W Pentreath
- Department of Biological Sciences, University of Salford, Manchester, UK
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Suzuki Y, Apostolova MD, Cherian MG. Astrocyte cultures from transgenic mice to study the role of metallothionein in cytotoxicity of tert-butyl hydroperoxide. Toxicology 2000; 145:51-62. [PMID: 10771131 DOI: 10.1016/s0300-483x(99)00220-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cell viability, lipid peroxidation (LPO) and hydrogen peroxide (H(2)O(2)) generation were measured in cultured primary astrocytes, from metallothionein (MT)-I isoform overexpressing transgenic (MT-I*), MT-I/MT-II null and control mice after exposure to tert-butylhydroperoxide (tBH). Astrocytes from MT-I* mice have high basal levels of both MT-I mRNA and MT protein, whereas there is only MT-III isoform in astrocytes from MT-I/MT-II null mice. The results showed that (1) cultured astrocytes from MT-I* mice were most resistant to the cytotoxicity of tBH and those from MT-I/MT-II null mice were most sensitive to the cytotoxicity of tBH; (2) LPO after exposure to tBH were increased in all cells, but the levels were the highest in astrocytes from MT-I/MT-II null mice, while those in MT-I* mice were the lowest; (3) the levels of H(2)O(2) in cultured astrocytes from MT-I* mice were the lowest, while those in astrocytes from MT-I/MT-II null mice were the highest. These results support the hypothesis that MT can scavenge free radicals and protect astrocytes from oxidative stress.
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Affiliation(s)
- Y Suzuki
- Department of Pathology, Faculty of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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Adlard PA, West AK, Vickers JC. Increased density of metallothionein I/II-immunopositive cortical glial cells in the early stages of Alzheimer's disease. Neurobiol Dis 1998; 5:349-56. [PMID: 10069577 DOI: 10.1006/nbdi.1998.0203] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We have examined the possible role of metallothionein I/II (MT I/II) in Alzheimer's disease (AD), with a focus on the cellular localization of MT I/II relative to the astrocyte marker, glial fibrillary acidic protein (GFAP). In AD and preclinical AD cases, MT I/II immunolabeling was present in glial cells and did not show a spatial relationship with beta-amyloid plaques or neurofibrillary pathology. There was a six- to sevenfold increase in both MT I/II- and GFAP-labeled cells in the gray matter of AD cases, relative to non-AD cases. However, there was a threefold increase in MT I/II-immunoreactive cells, but not GFAP-labeled cells, in the gray matter of preclinical AD cases compared to non-AD cases. Therefore, the specific increase in MT I/II is associated with the initial stages of the disease process, perhaps due to oxidative stress or the mismetabolism of heavy metals.
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Affiliation(s)
- P A Adlard
- Division of Pathology, University of Tasmania, Hobart, Australia
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Lovejoy DA, Aubry JM, Turnbull A, Sutton S, Potter E, Yehling J, Rivier C, Vale WW. Ectopic expression of the CRF-binding protein: minor impact on HPA axis regulation but induction of sexually dimorphic weight gain. J Neuroendocrinol 1998; 10:483-91. [PMID: 9700675 DOI: 10.1046/j.1365-2826.1998.00206.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Corticotrophin-releasing factor (CRF) and urocortin possess a high-affinity binding protein. Although the CRF binding protein (BP) can sequester these ligands and inhibit their activity, the endogenous activity of this protein is not understood. Therefore, transgenic mouse lines that over-express the CRF-BP were created. The transgene was constructed by ligating rat CRF-BP cDNA (1.1 kb) between a mouse metallothionein-I promoter (1.8 kb) and a nonfunctional human growth hormone gene sequence (2.1 kb) in a modified pBR322 plasmid and microinjecting the transgene into C57BL/6 x SJL hybrid ova. The transgene was expressed in 50% in both male and female progeny. All transgenic lines were maintained by crossing transgenic animals with wild-type C57BL/6 mates. Reverse-transcriptase (RT) PCR of the CRF-BP transgene showed that it is widely expressed not only in the brain and pituitary, but also peripheral tissues including the liver, kidney and spleen. Transgenic animals of both sexes showed significant increases in weight gain as established by analysis of variance; however, the weight gain profiles for each sex were distinct. High levels of circulating CRF-BP were detected in the transgenic animals, but the basal ACTH and corticosterone levels were not significantly decreased compared to wild-type littermates. The hypothalamopituitary-adrenal (HPA) axis was stimulated by systemic inflammation induced with lipopolysaccharide (LPS). An expected increase in transgene expression was observed and was accompanied by a significant attenuation of ACTH secretion at 3 h after LPS injection in the transgenic males but not the females. These data suggest that HPA axis regulation is significantly affected only with very high circulating levels of CRF-BP. Moreover, this work supports previous studies that implicate CRF and urocortin in the regulation of appetite and the binding protein expression may play a sexually dimorphic role in regulating this and other responses.
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Affiliation(s)
- D A Lovejoy
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, CA 92037, USA
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Vela JM, Hidalgo J, González B, Castellano B. Induction of metallothionein in astrocytes and microglia in the spinal cord from the myelin-deficient jimpy mouse. Brain Res 1997; 767:345-55. [PMID: 9367267 DOI: 10.1016/s0006-8993(97)00628-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Jimpy is a shortened life-span murine mutant whose genetic disorder results in severe pathological alterations in the CNS, including hypomyelination, oligodendrocyte death and strong astroglial and microglial reaction. The knowledge of metallothionein (MT) regulation in the CNS and especially of MT presence in specific glial cell types under pathological conditions is scarce. In the present study, immunocytochemical detection of MT-I + II has been performed in spinal cord sections from 10-12- and 20-22-day-old jimpy and normal animals. The identification of MT-positive glial cells was achieved through double labeling combining MT immunocytochemistry and selective markers for oligodendrocytes, astrocytes and microglia. MT was found in glial cells and was present in the spinal cord of jimpy and normal mice at both ages, but there were remarkable differences in MT expression and in the nature of MT-positive glial cells depending on the type of mouse. The number of MT-positive cells was higher in jimpy than in normal spinal cords. This was apparent in all spinal cord areas, although it was more pronounced in white than in the gray matter and at 20-22 days than at 10-12 days. The mean number of MT-positive glia in the jimpy white matter was 1.9-fold (10-12 days) and 2.4-fold (20-22 days) higher than in the normal one. Astrocytes were the only parenchymal glial cells that were positively identified as MT-producing cells in normal animals. Interestingly, MT in the jimpy spinal cord was localized not only in astrocytes but also in microglial cells. The occurrence of MT induction in relation to reactive astrocytes and microglia, and its role in neuropathological conditions is discussed.
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Affiliation(s)
- J M Vela
- Department of Cell Biology and Physiology, Faculty of Medicine, Autonomous University of Barcelona, Bellaterra, Spain
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Hidalgo J, Belloso E, Hernandez J, Gasull T, Molinero A. Role of Glucocorticoids on Rat Brain Metallothionein-I and -III Response to Stress. Stress 1997; 1:231-240. [PMID: 9787247 DOI: 10.3109/10253899709013743] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The metallothionein (MT) gene family consists of four members (MT-I through -IV) that are tightly regulated during development. Whereas MT-I and MT-II are widely expressed isoforms, MT-III has been found to be mainly expressed in the central nervous system in adult animals, and is the only isoform that inhibits survival and neurite formation of cortical neurons in vitro. A number of models of brain injury have been shown to affect MT-III mRNA levels, which has been suggested to be related to the putative neurotrophic role of this protein. However, a stress response will presumably be associated to the brain injury which could, in turn, drive MT-III regulation. In the present report the effect of a classical stress model, immobilization stress, on brain MT regulation has been studied in rats. MT-I+II protein levels were measured by radioimmunoassay in up to eight brain areas and, as expected, it was found that stress increased selectively MT-I+II levels. Adrenalectomy (ADX) had a general decreasing effect on basal MT-I+II levels; however, ADX blunted the MT-I+II response to stress in cerebellum and presumably in frontal cortex and medulla plus pons but not in the hypothalamus. MT-I mRNA measurements were in accordance with the MT-I+II protein levels in the brain areas studied. In contrast to MT-I mRNA, MT-III mRNA levels of brain cortex tended to decrease during stress, although this effect was not statistically significant. ADX also tended to decrease basal MT-III mRNA levels. Northern blot assays of pooled mRNAs suggested similar differential regulation of these two brain MT isoforms in the cerebellum. These results indicate that glucocorticoids mediate brain MT-I+II response to stress in some but not all brain areas, that a role of these hormones is likely also for MT-III, and that the regulation of MT isoforms differs substantially in the brain.
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Affiliation(s)
- J Hidalgo
- Departamento de Biología Celular y Fisiología, Unidad de Fisiología Animal, Facultad de Ciencias, Universidad Autónoma de Barcelona, Bellaterra 08193, Barcelona, Spain
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Disruption of the metallothionein-III gene in mice: analysis of brain zinc, behavior, and neuron vulnerability to metals, aging, and seizures. J Neurosci 1997. [PMID: 9006971 DOI: 10.1523/jneurosci.17-04-01271.1997] [Citation(s) in RCA: 193] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metallothionein-III (MT-III), a brain-specific member of the metallothionein family of metal-binding proteins, is abundant in glutamatergic neurons that release zinc from their synaptic terminals, such as hippocampal pyramidal neurons and dentate granule cells. MT-III may be an important regulator of zinc in the nervous system, and its absence has been implicated in the development of Alzheimer's disease. However, the roles of MT-III in brain physiology and pathophysiology have not been elucidated. Mice lacking MT-III because of targeted gene inactivation were generated to evaluate the neurobiological significance of MT-III. MT-III-deficient mice had decreased concentrations of zinc in several brain regions, including hippocampus, but the pool of histochemically reactive zinc was not disturbed. Mutant mice exhibited normal spatial learning in the Morris water maze and were not sensitive to systemic zinc or cadmium exposure. No neuropathology or behavioral deficits were detected in 2-year-old MT-III-deficient mice, but the age-related increase in glial fibrillary acidic protein expression was more pronounced in mutant brain. MT-III-deficient mice were more susceptible to seizures induced by kainic acid and subsequently exhibited greater neuron injury in the CA3 field of hippocampus. Conversely, transgenic mice containing elevated levels of MT-III were more resistant to CA3 neuron injury induced by seizures. These observations suggest a potential role for MT-III in zinc regulation during neural stimulation.
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Aschner M, Cherian MG, Klaassen CD, Palmiter RD, Erickson JC, Bush AI. Metallothioneins in brain--the role in physiology and pathology. Toxicol Appl Pharmacol 1997; 142:229-42. [PMID: 9070344 DOI: 10.1006/taap.1996.8054] [Citation(s) in RCA: 150] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A symposium on the role of brain metallothioneins (MTs) in physiology and pathology was held at the 1996 Annual Society of Toxicology Meeting in Anaheim, California. The objectives of this symposium were to: (1) review the physiologic function of MTs, (2) examine the distribution of brain MTs with particular emphasis on cell-specific localization (neurons vs neuroglia), (3) discuss MT gene responsiveness upon toxic insult with metals, and (4) discuss the potential role of MTs in the etiology of neurodegenerative disorders. Dr. Cherian discussed the biochemical properties of the MTs, emphasizing structural similarities and differences between the MTs. Dr. Klaassen addressed the expression and distribution of the MTs in brains with special reference to the cell-specific localization of MTs. Dr. Aschner provided data illustrating a potential role for MTs in attenuating the cytotoxicity caused by methylmercury (MeHg) in cultured neonatal astrocytes. Dr. Palmiter discussed the properties of MT-III and the increased sensitivity of MT-III knockout mice to kainate-induced seizures. Cerebral zinc metabolism, its relationship to MT homeostasis, and its pathogenic potential in Alzheimer's disease was addressed by Dr. Bush.
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Affiliation(s)
- M Aschner
- Department of Physiology and Pharmacology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North Carolina 27157-1083, USA
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