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Darwish M, Hattori S, Nishizono H, Miyakawa T, Yachie N, Takao K. Comprehensive behavioral analyses of mice with a glycine receptor alpha 4 deficiency. Mol Brain 2023; 16:44. [PMID: 37217969 DOI: 10.1186/s13041-023-01033-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
Glycine receptors (GlyRs) are ligand-gated chloride channels comprising alpha (α1-4) and β subunits. The GlyR subunits play major roles in the mammalian central nervous system, ranging from regulating simple sensory information to modulating higher-order brain function. Unlike the other GlyR subunits, GlyR α4 receives relatively little attention because the human ortholog lacks a transmembrane domain and is thus considered a pseudogene. A recent genetic study reported that the GLRA4 pseudogene locus on the X chromosome is potentially involved in cognitive impairment, motor delay and craniofacial anomalies in humans. The physiologic roles of GlyR α4 in mammal behavior and its involvement in disease, however, are not known. Here we examined the temporal and spatial expression profile of GlyR α4 in the mouse brain and subjected Glra4 mutant mice to a comprehensive behavioral analysis to elucidate the role of GlyR α4 in behavior. The GlyR α4 subunit was mainly enriched in the hindbrain and midbrain, and had relatively lower expression in the thalamus, cerebellum, hypothalamus, and olfactory bulb. In addition, expression of the GlyR α4 subunit gradually increased during brain development. Glra4 mutant mice exhibited a decreased amplitude and delayed onset of the startle response compared with wild-type littermates, and increased social interaction in the home cage during the dark period. Glra4 mutants also had a low percentage of entries into open arms in the elevated plus-maze test. Although mice with GlyR α4 deficiency did not show motor and learning abnormalities reported to be associated in human genomics studies, they exhibited behavioral changes in startle response and social and anxiety-like behavior. Our data clarify the spatiotemporal expression pattern of the GlyR α4 subunit and suggest that glycinergic signaling modulates social, startle, and anxiety-like behaviors in mice.
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Affiliation(s)
- Mohamed Darwish
- Department of Behavioral Physiology, Graduate School of Innovative Life Science, University of Toyama, Toyama, Japan
- Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Satoko Hattori
- Division of Systems Medical Science, Center for Comprehensive Medical Science, Fujita Health University, Aichi, Toyoake, Japan
| | - Hirofumi Nishizono
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa, Japan
| | - Tsuyoshi Miyakawa
- Division of Systems Medical Science, Center for Comprehensive Medical Science, Fujita Health University, Aichi, Toyoake, Japan
| | - Nozomu Yachie
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
- School of Biomedical Engineering, The University of British Columbia, Vancouver, Canada
| | - Keizo Takao
- Department of Behavioral Physiology, Graduate School of Innovative Life Science, University of Toyama, Toyama, Japan.
- Department of Behavioral Physiology, Faculty of Medicine, University of Toyama, Toyama, Japan.
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan.
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2
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Wu T, Kumar M, Zhang J, Zhao S, Drobizhev M, McCollum M, Anderson CT, Wang Y, Pokorny A, Tian X, Zhang Y, Tzounopoulos T, Ai HW. A genetically encoded far-red fluorescent indicator for imaging synaptically released Zn 2. SCIENCE ADVANCES 2023; 9:eadd2058. [PMID: 36857451 PMCID: PMC9977179 DOI: 10.1126/sciadv.add2058] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
Synaptic zinc ion (Zn2+) has emerged as a key neuromodulator in the brain. However, the lack of research tools for directly tracking synaptic Zn2+ in the brain of awake animals hinders our rigorous understanding of the physiological and pathological roles of synaptic Zn2+. In this study, we developed a genetically encoded far-red fluorescent indicator for monitoring synaptic Zn2+ dynamics in the nervous system. Our engineered far-red fluorescent indicator for synaptic Zn2+ (FRISZ) displayed a substantial Zn2+-specific turn-on response and low-micromolar affinity. We genetically anchored FRISZ to the mammalian extracellular membrane via a transmembrane (TM) ⍺ helix and characterized the resultant FRISZ-TM construct at the mammalian cell surface. We used FRISZ-TM to image synaptic Zn2+ in the auditory cortex in acute brain slices and awake mice in response to electric and sound stimuli, respectively. Thus, this study establishes a technology for studying the roles of synaptic Zn2+ in the nervous system.
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Affiliation(s)
- Tianchen Wu
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Manoj Kumar
- Department of Otolaryngology, Pittsburgh Hearing Research Center, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jing Zhang
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Shengyu Zhao
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
| | - Mikhail Drobizhev
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717-384, USA
| | - Mason McCollum
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Charles T. Anderson
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Ying Wang
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | - Xiaodong Tian
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yiyu Zhang
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Thanos Tzounopoulos
- Department of Otolaryngology, Pittsburgh Hearing Research Center, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hui-wang Ai
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
- The UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, VA 22908, USA
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3
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Gallagher CI, Ha DA, Harvey RJ, Vandenberg RJ. Positive Allosteric Modulators of Glycine Receptors and Their Potential Use in Pain Therapies. Pharmacol Rev 2022; 74:933-961. [PMID: 36779343 PMCID: PMC9553105 DOI: 10.1124/pharmrev.122.000583] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/26/2022] [Accepted: 05/13/2022] [Indexed: 11/22/2022] Open
Abstract
Glycine receptors are ligand-gated ion channels that mediate synaptic inhibition throughout the mammalian spinal cord, brainstem, and higher brain regions. They have recently emerged as promising targets for novel pain therapies due to their ability to produce antinociception by inhibiting nociceptive signals within the dorsal horn of the spinal cord. This has greatly enhanced the interest in developing positive allosteric modulators of glycine receptors. Several pharmaceutical companies and research facilities have attempted to identify new therapeutic leads by conducting large-scale screens of compound libraries, screening new derivatives from natural sources, or synthesizing novel compounds that mimic endogenous compounds with antinociceptive activity. Advances in structural techniques have also led to the publication of multiple high-resolution structures of the receptor, highlighting novel allosteric binding sites and providing additional information for previously identified binding sites. This has greatly enhanced our understanding of the functional properties of glycine receptors and expanded the structure activity relationships of novel pharmacophores. Despite this, glycine receptors are yet to be used as drug targets due to the difficulties in obtaining potent, selective modulators with favorable pharmacokinetic profiles that are devoid of side effects. This review presents a summary of the structural basis for how current compounds cause positive allosteric modulation of glycine receptors and discusses their therapeutic potential as analgesics. SIGNIFICANCE STATEMENT: Chronic pain is a major cause of disability, and in Western societies, this will only increase as the population ages. Despite the high level of prevalence and enormous socioeconomic burden incurred, treatment of chronic pain remains limited as it is often refractory to current analgesics, such as opioids. The National Institute for Drug Abuse has set finding effective, safe, nonaddictive strategies to manage chronic pain as their top priority. Positive allosteric modulators of glycine receptors may provide a therapeutic option.
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Affiliation(s)
- Casey I Gallagher
- Molecular Biomedicine, School of Medical Sciences, University of Sydney, Sydney, Australia (C.I.G., D.A.H., R.J.V.) and Biomedical Science, School of Health and Behavioural Sciences and Sunshine Coast Health Institute, University of the Sunshine Coast, Maroochydore, Australia (R.J.H.)
| | - Damien A Ha
- Molecular Biomedicine, School of Medical Sciences, University of Sydney, Sydney, Australia (C.I.G., D.A.H., R.J.V.) and Biomedical Science, School of Health and Behavioural Sciences and Sunshine Coast Health Institute, University of the Sunshine Coast, Maroochydore, Australia (R.J.H.)
| | - Robert J Harvey
- Molecular Biomedicine, School of Medical Sciences, University of Sydney, Sydney, Australia (C.I.G., D.A.H., R.J.V.) and Biomedical Science, School of Health and Behavioural Sciences and Sunshine Coast Health Institute, University of the Sunshine Coast, Maroochydore, Australia (R.J.H.)
| | - Robert J Vandenberg
- Molecular Biomedicine, School of Medical Sciences, University of Sydney, Sydney, Australia (C.I.G., D.A.H., R.J.V.) and Biomedical Science, School of Health and Behavioural Sciences and Sunshine Coast Health Institute, University of the Sunshine Coast, Maroochydore, Australia (R.J.H.)
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4
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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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5
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Kong M, Xing F, Zhu S. A new tripodal 8-hydroxyquinoline as a high sensitivity fluorescence sensor for Zn(II) in ethanol and its two morphology in solid. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Hoque A, Islam MS, Khan MMA, Ghosh S, Sekh MA, Hussain S, Alam MA. Biphenyl Containing Amido Schiff base Derivative as a Turn-on Fluorescent Chemosensor for Al3+ and Zn2+ ions. NEW J CHEM 2022. [DOI: 10.1039/d2nj03144b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A hydrazine derived Bis(2-hydroxybenzylidene)-[1,1'-biphenyl]-2,2'-dicarbohydrazide (sensor 1) has been synthesized and its sensing properties towards metal ions has been demonstrated using simple UV-visble spectroscopic, fluorometric technique and visible colour change. The...
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Naskar B, Das Mukhopadhyay C, Goswami S. A new diformyl phenol based chemosensor selectively detects Zn 2+ and Co 2+ in the nanomolar range in 100% aqueous medium and HCT live cells. NEW J CHEM 2022. [DOI: 10.1039/d2nj01478e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new diformyl phenol based chemosensor that can sense Zn2+ and Co2+ in the nanomolar range in 100% aqueous solution and in HCT cells was explored.
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Affiliation(s)
- Barnali Naskar
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
- Department of Chemistry, Lalbaba College, University of Calcutta, Howrah 711202, India
| | - Chitrangada Das Mukhopadhyay
- Centre for Healthcare Science & Technology, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Sanchita Goswami
- Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
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Zhan FX, Wang SG, Cao L. Advances in hyperekplexia and other startle syndromes. Neurol Sci 2021; 42:4095-4107. [PMID: 34379238 DOI: 10.1007/s10072-021-05493-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/14/2021] [Indexed: 02/03/2023]
Abstract
Startle, a basic alerting reaction common to all mammals, is described as a sudden involuntary movement of the body evoked by all kinds of sudden and unexpected stimulus. Startle syndromes are heterogeneous groups of disorders with abnormal and exaggerated responses to startling events, including hyperekplexia, stimulus-induced disorders, and neuropsychiatric startle syndromes. Hyperekplexia can be attributed to a genetic, idiopathic, or symptomatic cause. Excluding secondary factors, hereditary hyperekplexia, a rare neurogenetic disorder with highly genetic heterogeneity, is characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli, and followed by a short period of general stiffness. It mainly arises from defects of inhibitory glycinergic neurotransmission. GLRA1 is the major pathogenic gene of hereditary hyperekplexia, along with many other genes involved in the function of glycinergic inhibitory synapses. While about 40% of patients remain negative genetic findings. Clonazepam, which can specifically upgrade the GABARA1 chloride channels, is the main and most effective administration for hereditary hyperekplexia patients. In this review, with the aim at enhancing the recognition and prompting potential treatment for hyperekplexia, we focused on discussing the advances in hereditary hyperekplexia genetics and the expound progress in pathogenic mechanisms of the glycinergic-synapse-related pathway and then followed by a brief overview of other common startle syndromes.
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Affiliation(s)
- Fei-Xia Zhan
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi Shan Road, Shanghai, 200233, China
| | - Shi-Ge Wang
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi Shan Road, Shanghai, 200233, China
| | - Li Cao
- Department of Neurology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi Shan Road, Shanghai, 200233, China.
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9
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Mu X, Shi L, Yan L, Tang N. A 2-Hydroxy-1-naphthaldehyde Schiff Base for Turn-on Fluorescence Detection of Zn 2+ Based on PET Mechanism. J Fluoresc 2021; 31:971-979. [PMID: 33860872 DOI: 10.1007/s10895-021-02732-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Zinc ion is closely related to human health. Its content in human body is small, while the effect is large. However, it is not the more the better, must be in a scientific balance. Therefore, it is significant to the rapid detection of Zn2+ in the environment and organism. Herein, a fluorescent probe based on 2-hydroxy-1-naphthalene formaldehyde and furan-2-carbohydrazide was conveniently synthesized via Schiff base reaction. And this probe has been successfully applied to the accurate and quantitative detection of Zn2+ in real samples, showing turn on fluorescence, good selectivity, very low detection limit, real time response and reusability. In addition, this probe has the potential application to trace Zn2+ in living cells with low cytotoxicity.
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Affiliation(s)
- Xinyue Mu
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi, 541006, People's Republic of China
| | - Liping Shi
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi, 541006, People's Republic of China
| | - Liqiang Yan
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi, 541006, People's Republic of China.
| | - Ningli Tang
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi, 541006, People's Republic of China.
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10
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Li Z, Wang J, Xiao L, Wang J, Yan H. A dual-response fluorescent probe for Al3+ and Zn2+ in aqueous medium based on benzothiazole and its application in living cells. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2020.120147] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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11
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Krall RF, Tzounopoulos T, Aizenman E. The Function and Regulation of Zinc in the Brain. Neuroscience 2021; 457:235-258. [PMID: 33460731 DOI: 10.1016/j.neuroscience.2021.01.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 12/31/2022]
Abstract
Nearly sixty years ago Fredrich Timm developed a histochemical technique that revealed a rich reserve of free zinc in distinct regions of the brain. Subsequent electron microscopy studies in Timm- stained brain tissue found that this "labile" pool of cellular zinc was highly concentrated at synaptic boutons, hinting a possible role for the metal in synaptic transmission. Although evidence for activity-dependent synaptic release of zinc would not be reported for another twenty years, these initial findings spurred decades of research into zinc's role in neuronal function and revealed a diverse array of signaling cascades triggered or regulated by the metal. Here, we delve into our current understanding of the many roles zinc plays in the brain, from influencing neurotransmission and sensory processing, to activating both pro-survival and pro-death neuronal signaling pathways. Moreover, we detail the many mechanisms that tightly regulate cellular zinc levels, including metal binding proteins and a large array of zinc transporters.
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Affiliation(s)
- Rebecca F Krall
- Department of Neurobiology, University of Pittsburgh School of Medicine, USA; Department of Otolaryngology, University of Pittsburgh School of Medicine, USA; Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, USA; Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, USA
| | - Thanos Tzounopoulos
- Department of Otolaryngology, University of Pittsburgh School of Medicine, USA; Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, USA.
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, USA; Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, USA; Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, USA.
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12
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John J, Kinra M, Mudgal J, Viswanatha GL, Nandakumar K. Animal models of chemotherapy-induced cognitive decline in preclinical drug development. Psychopharmacology (Berl) 2021; 238:3025-3053. [PMID: 34643772 PMCID: PMC8605973 DOI: 10.1007/s00213-021-05977-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 08/31/2021] [Indexed: 12/23/2022]
Abstract
RATIONALE Chemotherapy-induced cognitive impairment (CICI), chemobrain, and chemofog are the common terms for mental dysfunction in a cancer patient/survivor under the influence of chemotherapeutics. CICI is manifested as short/long term memory problems and delayed mental processing, which interferes with a person's day-to-day activities. Understanding CICI mechanisms help in developing therapeutic interventions that may alleviate the disease condition. Animal models facilitate critical evaluation to elucidate the underlying mechanisms and form an integral part of verifying different treatment hypotheses and strategies. OBJECTIVES A methodical evaluation of scientific literature is required to understand cognitive changes associated with the use of chemotherapeutic agents in different preclinical studies. This review mainly emphasizes animal models developed with various chemotherapeutic agents individually and in combination, with their proposed mechanisms contributing to the cognitive dysfunction. This review also points toward the analysis of chemobrain in healthy animals to understand the mechanism of interventions in absence of tumor and in tumor-bearing animals to mimic human cancer conditions to screen potential drug candidates against chemobrain. RESULTS Substantial memory deficit as a result of commonly used chemotherapeutic agents was evidenced in healthy and tumor-bearing animals. Spatial and episodic cognitive impairments, alterations in neurotrophins, oxidative and inflammatory markers, and changes in long-term potentiation were commonly observed changes in different animal models irrespective of the chemotherapeutic agent. CONCLUSION Dyscognition exists as one of the serious side effects of cancer chemotherapy. Due to differing mechanisms of chemotherapeutic agents with differing tendencies to alter behavioral and biochemical parameters, chemotherapy may present a significant risk in resulting memory impairments in healthy as well as tumor-bearing animals.
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Affiliation(s)
- Jeena John
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka India 576104
| | - Manas Kinra
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka India 576104
| | - Jayesh Mudgal
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka India 576104
| | - G. L. Viswanatha
- Independent Researcher, Kengeri, Bangalore, Karnataka India 560060
| | - K. Nandakumar
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka India 576104
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13
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Krall RF, Moutal A, Phillips MB, Asraf H, Johnson JW, Khanna R, Hershfinkel M, Aizenman E, Tzounopoulos T. Synaptic zinc inhibition of NMDA receptors depends on the association of GluN2A with the zinc transporter ZnT1. SCIENCE ADVANCES 2020; 6:eabb1515. [PMID: 32937457 PMCID: PMC7458442 DOI: 10.1126/sciadv.abb1515] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 05/20/2020] [Indexed: 05/08/2023]
Abstract
The NMDA receptor (NMDAR) is inhibited by synaptically released zinc. This inhibition is thought to be the result of zinc diffusion across the synaptic cleft and subsequent binding to the extracellular domain of the NMDAR. However, this model fails to incorporate the observed association of the highly zinc-sensitive NMDAR subunit GluN2A with the postsynaptic zinc transporter ZnT1, which moves intracellular zinc to the extracellular space. Here, we report that disruption of ZnT1-GluN2A association by a cell-permeant peptide strongly reduced NMDAR inhibition by synaptic zinc in mouse dorsal cochlear nucleus synapses. Moreover, synaptic zinc inhibition of NMDARs required postsynaptic intracellular zinc, suggesting that cytoplasmic zinc is transported by ZnT1 to the extracellular space in close proximity to the NMDAR. These results challenge a decades-old dogma on how zinc inhibits synaptic NMDARs and demonstrate that presynaptic release and a postsynaptic transporter organize zinc into distinct microdomains to modulate NMDAR neurotransmission.
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Affiliation(s)
- Rebecca F Krall
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Matthew B Phillips
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hila Asraf
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Jon W Johnson
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Elias Aizenman
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Thanos Tzounopoulos
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Abstract
The inhibitory glycine receptor is a member of the Cys-loop superfamily of ligand-gated ion channels. It is the principal mediator of rapid synaptic inhibition in the spinal cord and brainstem and plays an important role in the modulation of higher brain functions including vision, hearing, and pain signaling. Glycine receptor function is controlled by only a few agonists, while the number of antagonists and positive or biphasic modulators is steadily increasing. These modulators are important for the study of receptor activation and regulation and have found clinical interest as potential analgesics and anticonvulsants. High-resolution structures of the receptor have become available recently, adding to our understanding of structure-function relationships and revealing agonistic, inhibitory, and modulatory sites on the receptor protein. This Review presents an overview of compounds that activate, inhibit, or modulate glycine receptor function in vitro and in vivo.
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Affiliation(s)
- Ulrike Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo 11835, Egypt
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Zhan F, Zhang C, Wang S, Zhu Z, Chen G, Zhao M, Cao L. Excessive Startle with Novel GLRA1 Mutations in 4 Chinese Patients and a Literature Review of GLRA1-Related Hyperekplexia. J Clin Neurol 2020; 16:230-236. [PMID: 32319239 PMCID: PMC7174104 DOI: 10.3988/jcn.2020.16.2.230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 11/17/2022] Open
Abstract
Background and Purpose Hyperekplexia (HPX), a rare neurogenetic disorder, is classically characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli and followed by a shortly general stiffness. Glycine receptor alpha 1 (GLRA1) is the major pathogenic gene of the disease. We described the clinical manifestations of genetically confirmed HPX patients and made a literature review of GLRA1-related HPX to improve the early recognition and prompt the management of the disorder. Methods Extensive clinical evaluations were analyzed in 4 Chinese HPX patients from two unrelated families. Next generation sequencing was conducted in the probands. Sanger sequence and segregation analysis were applied to confirm the findings. Results All four patients including 3 males and 1 female presented with excessive startle reflex, a cautious gait and recurrent falls. Moreover, startle episodes were dramatically improved with the treatment of clonazepam in all cases. Exome sequencing revealed 2 homozygous GLRA1 mutations in the patients. The mutation c.1286T>A p.I429N has been previously reported, while c.754delC p.L252* is novel. Conclusions HPX is a treatable disease, and clonazepam is the drug of choice. By studying and reviewing the disorder, we summarized the phenotype, expanded the genotype spectrum, and discussed the possible pathogenic mechanisms to enhance the understanding and recognition of the disease. Early awareness of the disease is crucial to the prompt and proper administration, as well as the genetic counseling.
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Affiliation(s)
- Feixia Zhan
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chao Zhang
- Department of Neurology, Suzhou Hospital Affiliated to Anhui Medical University, Suzhou, China
| | - Shige Wang
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zeyu Zhu
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guang Chen
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mingliang Zhao
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Cao
- Department of Neurology, RuiJin Hospital & RuiJin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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16
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Chen X, Ma Y, Zhang Y, Chen Q, Wang H, Wang Z. A Selective and Reversible Fluorescent Probe for Zn
2+
Detection in Living Cells. ChemistrySelect 2020. [DOI: 10.1002/slct.202000662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Xin Chen
- Department of Chemistry, College of ScienceChina Agricultural University Beijing 100193 P.R. China
| | - Yufan Ma
- State Key laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical Technology Beijing 100029 P.R. China
| | - Yuanyuan Zhang
- Department of Chemistry, College of ScienceChina Agricultural University Beijing 100193 P.R. China
| | - Qing Chen
- College of Resource and Environmental ScienceChina Agricultural University Beijing 100193 P.R. China
| | - Hongmei Wang
- Department of Chemistry, College of ScienceChina Agricultural University Beijing 100193 P.R. China
| | - Zhuo Wang
- State Key laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical Technology Beijing 100029 P.R. China
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17
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Edlow AG, Guedj F, Sverdlov D, Pennings JLA, Bianchi DW. Significant Effects of Maternal Diet During Pregnancy on the Murine Fetal Brain Transcriptome and Offspring Behavior. Front Neurosci 2019; 13:1335. [PMID: 31920502 PMCID: PMC6928003 DOI: 10.3389/fnins.2019.01335] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 11/27/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Maternal over- and undernutrition in pregnancy plays a critical role in fetal brain development and function. The effects of different maternal diet compositions on intrauterine programing of the fetal brain is a lesser-explored area. The goal of this study was to investigate the impact of two chowmaternal diets on fetal brain gene expression signatures, fetal/neonatal growth, and neonatal and adult behavior in a mouse model. METHODS Throughout pregnancy and lactation, female C57Bl/6J mice were fed one of two standard, commercially available chow diets (pellet versus powder). The powdered chow diet was relatively deficient in micronutrients and enriched for carbohydrates and n-3 long-chain polyunsaturated fatty acids compared to the pelleted chow. RNA was extracted from embryonic day 15.5 forebrains and hybridized to whole genome expression microarrays (N = 5/maternal diet group). Functional analyses of significantly differentially expressed fetal brain genes were performed using Ingenuity Pathways Analysis and Gene Set Enrichment Analysis. Neonatal behavior was assessed using a validated scale (N = 62 pellet-exposed and 31 powder-exposed). Hippocampal learning, locomotor behavior, and motor coordination were assessed in a subset of adults using fear conditioning, open field testing, and Rotarod tests (N = 16 pellet-exposed, 14 powder-exposed). RESULTS Comparing powdered to pelleted chow diets, neither maternal weight trajectory in pregnancy nor embryo size differed. Maternal powdered chow diet was associated with 1647 differentially expressed fetal brain genes. Functional analyses identified significant upregulation of canonical pathways and upstream regulators involved in cell cycle regulation, synaptic plasticity, and sensory nervous system development in the fetal brain, and significant downregulation of pathways related to cell and embryo death. Pathways related to DNA damage response, brain immune response, amino acid and fatty acid transport, and dopaminergic signaling were significantly dysregulated. Powdered chow-exposed neonates were significantly longer but not heavier than pelleted chow-exposed counterparts. On neonatal behavioral testing, powdered chow-exposed neonates achieved coordination- and strength-related milestones significantly earlier, but sensory maturation reflexes significantly later. On adult behavioral testing, powdered chow-exposed offspring exhibited hyperactivity and hippocampal learning deficits. CONCLUSION In wild-type offspring, two diets that differed primarily with respect to micronutrient composition had significant effects on the fetal brain transcriptome, neonatal and adult behavior. These effects did not appear to be mediated by alterations in gross maternal nutritional status nor fetal/neonatal weight. Maternal dietary content is an important variable to consider for investigators evaluating fetal brain development and offspring behavior.
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Affiliation(s)
- Andrea G. Edlow
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, United States
| | - Faycal Guedj
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, United States
| | - Deanna Sverdlov
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, United States
- Department of Obstetrics and Gynecology, Tufts Medical Center, Boston, MA, United States
| | | | - Diana W. Bianchi
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, United States
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18
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Berrones-Reyes JC, Muñoz-Flores BM, Cantón-Diáz AM, Treto-Suárez MA, Páez-Hernández D, Schott E, Zarate X, Jiménez-Pérez VM. Quantum chemical elucidation of the turn-on luminescence mechanism in two new Schiff bases as selective chemosensors of Zn 2+: synthesis, theory and bioimaging applications. RSC Adv 2019; 9:30778-30789. [PMID: 35529385 PMCID: PMC9072448 DOI: 10.1039/c9ra05010h] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 11/04/2019] [Accepted: 08/21/2019] [Indexed: 12/17/2022] Open
Abstract
We report the synthesis and characterization of two new selective zinc sensors (S,E)-11-amino-8-((2,4-di-tert-butyl-1-hydroxybenzylidene) amino)-11-oxopentanoic acid (A) and (S,E)-11-amino-8-((8-hydroxybenzylidene)amino)-11-oxopentanoic acid (B) based on a Schiff base and an amino acid. The fluorescent probes, after binding to Zn2+ ions, presented an enhancement in fluorescent emission intensity up to 30 times (ϕ = A 50.10 and B 18.14%). The estimated LOD for compounds A and B was 1.17 and 1.20 μM respectively (mixture of acetonitrile : water 1 : 1). Theoretical research has enabled us to rationalize the behaviours of the two selective sensors to Zn2+ synthesized in this work. Our results showed that in the free sensors, PET and ESIPT are responsible for the quenching of the luminescence and that the turn-on of luminescence upon coordination to Zn2+ is mainly induced by the elimination of the PET, which is deeply analysed through EDA, NOCV, molecular structures, excited states and electronic transitions via TD-DFT computations. Confocal fluorescence microscopy experiments demonstrate that compound A could be used as a fluorescent probe for Zn2+ in living cells.
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Affiliation(s)
- Jessica C Berrones-Reyes
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Ciudad Universitaria 66451 Nuevo León México
| | - Blanca M Muñoz-Flores
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Ciudad Universitaria 66451 Nuevo León México
| | - Arelly M Cantón-Diáz
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Ciudad Universitaria 66451 Nuevo León México
| | - Manuel A Treto-Suárez
- Doctorado en Fisicoquímica Molecular, Center of Applied Nanosciences (CENS), Universidad Andres Bello Ave. República #275 Santiago de Chile Chile
| | - Dayan Páez-Hernández
- Doctorado en Fisicoquímica Molecular, Center of Applied Nanosciences (CENS), Universidad Andres Bello Ave. República #275 Santiago de Chile Chile
| | - Eduardo Schott
- Departamento de Química Inorgánica, UC Energy Research Center, Facultad de Química de Farmacia, Pontificia Universidad Católica de Chile Avenida Vicuña Mackenna, 4860 Macul Santiago Chile
- Millennium Nuclei on Catalytic Processes towards Sustainable Chemistry (CSC) Chile
| | - Ximena Zarate
- Instituto de Ciencias Químicas Aplicadas, Theoretical and Computational Chemistry Center, Facultad de Ingeniería, Universidad Autónoma de Chile Av. Pedro de Valdivia 425 Santiago Chile
| | - Víctor M Jiménez-Pérez
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Ciudad Universitaria 66451 Nuevo León México
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López-Corcuera B, Arribas-González E, Aragón C. Hyperekplexia-associated mutations in the neuronal glycine transporter 2. Neurochem Int 2018; 123:95-100. [PMID: 29859229 DOI: 10.1016/j.neuint.2018.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 05/26/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022]
Abstract
Hyperekplexia or startle disease is a dysfunction of inhibitory glycinergic neurotransmission characterized by an exaggerated startle in response to trivial tactile or acoustic stimuli. Although rare, this disorder can have serious consequences, including sudden infant death. One of the most frequent causes of hyperekplexia are mutations in the SLC6A5 gene, encoding the neuronal glycine transporter 2 (GlyT2), a key component of inhibitory glycinergic presynapses involved in synaptic glycine recycling though sodium and chloride-dependent co-transport. Most GlyT2 mutations detected so far are recessive, but two dominant missense mutations have been described. The detailed analysis of these mutations has revealed structural cues on the quaternary structure of GlyT2, and opens the possibility that novel selective pharmacochaperones have potential therapeutic effects in hyperekplexia.
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Affiliation(s)
- Beatriz López-Corcuera
- Centro de Biología Molecular ''Severo Ochoa'', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain; IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Esther Arribas-González
- Centro de Biología Molecular ''Severo Ochoa'', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain; IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Carmen Aragón
- Centro de Biología Molecular ''Severo Ochoa'', Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain; IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid, Spain
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20
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Involvement of glycine receptor α1 subunits in cannabinoid-induced analgesia. Neuropharmacology 2018; 133:224-232. [PMID: 29407767 DOI: 10.1016/j.neuropharm.2018.01.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/24/2018] [Accepted: 01/29/2018] [Indexed: 12/12/2022]
Abstract
Some cannabinoids have been shown to suppress chronic pain by targeting glycine receptors (GlyRs). Although cannabinoid potentiation of α3 GlyRs is thought to contribute to cannabinoid-induced analgesia, the role of cannabinoid potentiation of α1 GlyRs in cannabinoid suppression of chronic pain remains unclear. Here we report that dehydroxylcannabidiol (DH-CBD), a nonpsychoactive cannabinoid, significantly suppresses chronic inflammatory pain caused by noxious heat stimulation. This effect may involve spinal α1 GlyRs since the expression level of α1 subunits in the spinal cord is positively correlated with CFA-induced inflammatory pain and the GlyRs antagonist strychnine blocks the DH-CBD-induced analgesia. A point-mutation of S296A in TM3 of α1 GlyRs significantly inhibits DH-CBD potentiation of glycine currents (IGly) in HEK-293 cells and neurons in lamina I-II of spinal cord slices. To explore the in vivo consequence of DH-CBD potentiation of α1 GlyRs, we generated a GlyRα1S296A knock-in mouse line. We observed that DH-CBD-induced potentiation of IGly and analgesia for inflammatory pain was absent in GlyRα1S296A knock-in mice. These findings suggest that spinal α1 GlyR is a potential target for cannabinoid analgesia in chronic inflammatory pain.
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21
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Cherasse Y, Urade Y. Dietary Zinc Acts as a Sleep Modulator. Int J Mol Sci 2017; 18:ijms18112334. [PMID: 29113075 PMCID: PMC5713303 DOI: 10.3390/ijms18112334] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/02/2017] [Accepted: 11/02/2017] [Indexed: 12/31/2022] Open
Abstract
While zinc is known to be important for many biological processes in animals at a molecular and physiological level, new evidence indicates that it may also be involved in the regulation of sleep. Recent research has concluded that zinc serum concentration varies with the amount of sleep, while orally administered zinc increases the amount and the quality of sleep in mice and humans. In this review, we provide an exhaustive study of the literature connecting zinc and sleep, and try to evaluate which molecular mechanism is likely to be involved in this phenomenon. A better understanding should provide critical information not only about the way zinc is related to sleep but also about how sleep itself works and what its real function is.
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Affiliation(s)
- Yoan Cherasse
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 305-8575 Tsukuba, Japan.
| | - Yoshihiro Urade
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 305-8575 Tsukuba, Japan.
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22
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Kilb W, Fukuda A. Taurine as an Essential Neuromodulator during Perinatal Cortical Development. Front Cell Neurosci 2017; 11:328. [PMID: 29123472 PMCID: PMC5662885 DOI: 10.3389/fncel.2017.00328] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/04/2017] [Indexed: 01/10/2023] Open
Abstract
A variety of experimental studies demonstrated that neurotransmitters are an important factor for the development of the central nervous system, affecting neurodevelopmental events like neurogenesis, neuronal migration, programmed cell death, and differentiation. While the role of the classical neurotransmitters glutamate and gamma-aminobutyric acid (GABA) on neuronal development is well established, the aminosulfonic acid taurine has also been considered as possible neuromodulator during early neuronal development. The purpose of the present review article is to summarize the properties of taurine as neuromodulator in detail, focusing on the direct involvement of taurine on various neurodevelopmental events and the regulation of neuronal activity during early developmental epochs. The current knowledge is that taurine lacks a synaptic release mechanism but is released by volume-sensitive organic anion channels and/or a reversal of the taurine transporter. Extracellular taurine affects neurons and neuronal progenitor cells mainly via glycine, GABA(A), and GABA(B) receptors with considerable receptor and subtype-specific affinities. Taurine has been shown to directly influence neurogenesis in vitro as well as neuronal migration in vitro and in vivo. It provides a depolarizing signal for a variety of neuronal population in the immature central nervous system, thereby directly influencing neuronal activity. While in the neocortex, taurine probably enhance neuronal activity, in the immature hippocampus, a tonic taurinergic tone might be necessary to attenuate activity. In summary, taurine must be considered as an essential modulator of neurodevelopmental events, and possible adverse consequences on fetal and/or early postnatal development should be evaluated for pharmacological therapies affecting taurinergic functions.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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23
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Kambe T, Matsunaga M, Takeda TA. Understanding the Contribution of Zinc Transporters in the Function of the Early Secretory Pathway. Int J Mol Sci 2017; 18:ijms18102179. [PMID: 29048339 PMCID: PMC5666860 DOI: 10.3390/ijms18102179] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/12/2017] [Accepted: 10/15/2017] [Indexed: 01/07/2023] Open
Abstract
More than one-third of newly synthesized proteins are targeted to the early secretory pathway, which is comprised of the endoplasmic reticulum (ER), Golgi apparatus, and other intermediate compartments. The early secretory pathway plays a key role in controlling the folding, assembly, maturation, modification, trafficking, and degradation of such proteins. A considerable proportion of the secretome requires zinc as an essential factor for its structural and catalytic functions, and recent findings reveal that zinc plays a pivotal role in the function of the early secretory pathway. Hence, a disruption of zinc homeostasis and metabolism involving the early secretory pathway will lead to pathway dysregulation, resulting in various defects, including an exacerbation of homeostatic ER stress. The accumulated evidence indicates that specific members of the family of Zn transporters (ZNTs) and Zrt- and Irt-like proteins (ZIPs), which operate in the early secretory pathway, play indispensable roles in maintaining zinc homeostasis by regulating the influx and efflux of zinc. In this review, the biological functions of these transporters are discussed, focusing on recent aspects of their roles. In particular, we discuss in depth how specific ZNT transporters are employed in the activation of zinc-requiring ectoenzymes. The means by which early secretory pathway functions are controlled by zinc, mediated by specific ZNT and ZIP transporters, are also subjects of this review.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
| | - Mayu Matsunaga
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
| | - Taka-Aki Takeda
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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24
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Blakemore LJ, Trombley PQ. Zinc as a Neuromodulator in the Central Nervous System with a Focus on the Olfactory Bulb. Front Cell Neurosci 2017; 11:297. [PMID: 29033788 PMCID: PMC5627021 DOI: 10.3389/fncel.2017.00297] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/06/2017] [Indexed: 12/19/2022] Open
Abstract
The olfactory bulb (OB) is central to the sense of smell, as it is the site of the first synaptic relay involved in the processing of odor information. Odor sensations are first transduced by olfactory sensory neurons (OSNs) before being transmitted, by way of the OB, to higher olfactory centers that mediate olfactory discrimination and perception. Zinc is a common trace element, and it is highly concentrated in the synaptic vesicles of subsets of glutamatergic neurons in some brain regions including the hippocampus and OB. In addition, zinc is contained in the synaptic vesicles of some glycinergic and GABAergic neurons. Thus, zinc released from synaptic vesicles is available to modulate synaptic transmission mediated by excitatory (e.g., N-methyl-D aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)) and inhibitory (e.g., gamma-aminobutyric acid (GABA), glycine) amino acid receptors. Furthermore, extracellular zinc can alter the excitability of neurons through effects on a variety of voltage-gated ion channels. Consistent with the notion that zinc acts as a regulator of neuronal activity, we and others have shown zinc modulation (inhibition and/or potentiation) of amino acid receptors and voltage-gated ion channels expressed by OB neurons. This review summarizes the locations and release of vesicular zinc in the central nervous system (CNS), including in the OB. It also summarizes the effects of zinc on various amino acid receptors and ion channels involved in regulating synaptic transmission and neuronal excitability, with a special emphasis on the actions of zinc as a neuromodulator in the OB. An understanding of how neuroactive substances such as zinc modulate receptors and ion channels expressed by OB neurons will increase our understanding of the roles that synaptic circuits in the OB play in odor information processing and transmission.
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Affiliation(s)
- Laura J Blakemore
- Program in Neuroscience, Florida State UniversityTallahassee, FL, United States.,Department of Biological Science, Florida State UniversityTallahassee, FL, United States
| | - Paul Q Trombley
- Program in Neuroscience, Florida State UniversityTallahassee, FL, United States.,Department of Biological Science, Florida State UniversityTallahassee, FL, United States
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25
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The cancer chemotherapeutic agent paclitaxel (Taxol) reduces hippocampal neurogenesis via down-regulation of vesicular zinc. Sci Rep 2017; 7:11667. [PMID: 28916767 PMCID: PMC5601929 DOI: 10.1038/s41598-017-12054-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 09/01/2017] [Indexed: 01/10/2023] Open
Abstract
Chemotherapy-induced cognitive impairment (CICI) is increasingly recognized as a major unwanted side effect of an otherwise highly valuable life-saving technology. In part, this awareness is a result of increased cancer survival rates following chemotherapy. Altered hippocampal neurogenesis may play a role in mediating CICI. In particular, zinc could act as a key regulator of this process. To test this hypothesis, we administered paclitaxel (Px) to male C57BL/6 mice for set time periods and then evaluated the effects of Px treatment on hippocampal neurogenesis and vesicular zinc. We found that vesicular zinc levels and expression of zinc transporter 3 (ZnT3) were reduced in Px-treated mice, compared to vehicle-treated mice. Moreover, Px-treated mice demonstrated a significant decrease in the number of neuroblasts present. However, no difference in the number of progenitor cells were observed. In addition, zinc supplementation by treatment with ZnCl2 ameliorated the Px-induced decrease in hippocampal neurogenesis and cognitive impairment. These results suggest that via disruption of vesicular zinc stores in hippocampal mossy fiber terminals, chemotherapy may impinge upon one or more of the sequential stages involved in the maturation of new neurons derived via adult neurogenesis and thereby leads to the progressive cognitive decline associated with CICI.
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26
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McAllister BB, Dyck RH. Zinc transporter 3 (ZnT3) and vesicular zinc in central nervous system function. Neurosci Biobehav Rev 2017. [DOI: 10.1016/j.neubiorev.2017.06.006] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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27
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Cornelison GL, Daszkowski AW, Pflanz NC, Mihic SJ. Interactions between Zinc and Allosteric Modulators of the Glycine Receptor. J Pharmacol Exp Ther 2017; 361:1-8. [PMID: 28087784 DOI: 10.1124/jpet.116.239152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/12/2017] [Indexed: 01/01/2023] Open
Abstract
The glycine receptor is a pentameric ligand-gated ion channel that is involved in fast inhibitory neurotransmission in the central nervous system. Zinc is an allosteric modulator of glycine receptor function, enhancing the effects of glycine at nanomolar to low-micromolar concentrations and inhibiting its effects at higher concentrations. Low-nanomolar concentrations of contaminating zinc in electrophysiological buffers are capable of synergistically enhancing receptor modulation by other compounds, such as ethanol. This suggests that, unless accounted for, previous studies of glycine receptor modulation were measuring the effects of modulator plus comodulation by zinc on receptor function. Since zinc is present in vivo at a variety of concentrations, it will influence glycine receptor modulation by other pharmacologic agents. We investigated the utility of previously described "zinc-enhancement-insensitive" α1 glycine receptor mutants D80A, D80G, and W170S to probe for interactions between zinc and other allosteric modulators at the glycine receptor. We found that only the W170S mutation conferred complete abolishment of zinc enhancement across a variety of agonist and zinc concentrations. Using α1 W170S receptors, we established that, in addition to ethanol, zinc interacts with inhalants, but not volatile anesthetics, to synergistically enhance channel function. Additionally, we determined that this interaction is abolished at higher zinc concentrations when receptor-enhancing binding sites are saturated, suggesting a mechanism by which modulators such as ethanol and inhalants are capable of increasing receptor affinity for zinc, in addition to enhancing channel function on their own.
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Affiliation(s)
- Garrett L Cornelison
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol & Addiction Research, Institutes for Neuroscience and Cell & Molecular Biology, University of Texas at Austin, Austin, Texas
| | - Anna W Daszkowski
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol & Addiction Research, Institutes for Neuroscience and Cell & Molecular Biology, University of Texas at Austin, Austin, Texas
| | - Natasha C Pflanz
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol & Addiction Research, Institutes for Neuroscience and Cell & Molecular Biology, University of Texas at Austin, Austin, Texas
| | - S John Mihic
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol & Addiction Research, Institutes for Neuroscience and Cell & Molecular Biology, University of Texas at Austin, Austin, Texas
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28
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Zhu J, Zhang Y, Chen Y, Sun T, Tang Y, Huang Y, Yang Q, Ma D, Wang Y, Wang M. A Schiff base fluorescence probe for highly selective turn-on recognition of Zn2+. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2016.12.041] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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29
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Castro PL, Dominguez D, José Caballero M, Izquierdo M. Histochemical localization of zinc in the retina cells of gilthead sea bream (sparus aurata) fed different presentations of zinc. Synapse 2016; 71. [DOI: 10.1002/syn.21947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 11/06/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Pedro Luis Castro
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de Las Palmas de Gran Canaria Crta. Taliarte s/n; Telde 35214 Spain
| | - David Dominguez
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de Las Palmas de Gran Canaria Crta. Taliarte s/n; Telde 35214 Spain
| | - María José Caballero
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de Las Palmas de Gran Canaria Crta. Taliarte s/n; Telde 35214 Spain
| | - Marisol Izquierdo
- Grupo de Investigación en Acuicultura (GIA), IU-ECOAQUA, Universidad de Las Palmas de Gran Canaria Crta. Taliarte s/n; Telde 35214 Spain
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Zhang Y, Keramidas A, Lynch JW. The Free Zinc Concentration in the Synaptic Cleft of Artificial Glycinergic Synapses Rises to At least 1 μM. Front Mol Neurosci 2016; 9:88. [PMID: 27713689 PMCID: PMC5031599 DOI: 10.3389/fnmol.2016.00088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/07/2016] [Indexed: 11/13/2022] Open
Abstract
Zn2+ is concentrated into presynaptic vesicles at many central synapses and is released into the synaptic cleft by nerve terminal stimulation. There is strong evidence that synaptically released Zn2+ modulates glutamatergic neurotransmission, although there is debate concerning the peak concentration it reaches in the synaptic cleft. Glycine receptors (GlyRs), which mediate inhibitory neurotransmission in the spinal cord and brainstem, are potentiated by low nanomolar Zn2+ and inhibited by micromolar Zn2+. Mutations that selectively ablate Zn2+ potentiation result in hyperekplexia phenotypes suggesting that Zn2+ is a physiological regulator of glycinergic neurotransmission. There is, however, little evidence that Zn2+ is stored presynaptically at glycinergic terminals and an alternate possibility is that GlyRs are modulated by constitutively bound Zn2+. We sought to estimate the peak Zn2+ concentration in the glycinergic synaptic cleft as a means of evaluating whether it is likely to be synaptically released. We employed 'artificial' synapses because they permit the insertion of engineered α1β GlyRs with defined Zn2+ sensitivities into synapses. By comparing the effect of Zn2+ chelation on glycinergic IPSCs with the effects of defined Zn2+ and glycine concentrations applied rapidly to the same recombinant GlyRs in outside-out patches, we inferred that synaptic Zn2+ rises to at least 1 μM following a single presynaptic stimulation. Moreover, using the fast, high-affinity chelator, ZX1, we found no evidence for tonic Zn2+ bound constitutively to high affinity GlyR binding sites. We conclude that diffusible Zn2+ reaches 1 μM or higher and is therefore likely to be phasically released in artificial glycinergic synapses.
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Affiliation(s)
- Yan Zhang
- Queensland Brain Institute, The University of Queensland, Brisbane QLD, Australia
| | - Angelo Keramidas
- Queensland Brain Institute, The University of Queensland, Brisbane QLD, Australia
| | - Joseph W Lynch
- Queensland Brain Institute, The University of Queensland, BrisbaneQLD, Australia; School of Biomedical Sciences, The University of Queensland, BrisbaneQLD, Australia
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Zhang Y, Bode A, Nguyen B, Keramidas A, Lynch JW. Investigating the Mechanism by Which Gain-of-function Mutations to the α1 Glycine Receptor Cause Hyperekplexia. J Biol Chem 2016; 291:15332-41. [PMID: 27226610 DOI: 10.1074/jbc.m116.728592] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Indexed: 11/06/2022] Open
Abstract
Hyperekplexia is a rare human neuromotor disorder caused by mutations that impair the efficacy of glycinergic inhibitory neurotransmission. Loss-of-function mutations in the GLRA1 or GLRB genes, which encode the α1 and β glycine receptor (GlyR) subunits, are the major cause. Paradoxically, gain-of-function GLRA1 mutations also cause hyperekplexia, although the mechanism is unknown. Here we identify two new gain-of-function mutations (I43F and W170S) and characterize these along with known gain-of-function mutations (Q226E, V280M, and R414H) to identify how they cause hyperekplexia. Using artificial synapses, we show that all mutations prolong the decay of inhibitory postsynaptic currents (IPSCs) and induce spontaneous GlyR activation. As these effects may deplete the chloride electrochemical gradient, hyperekplexia could potentially result from reduced glycinergic inhibitory efficacy. However, we consider this unlikely as the depleted chloride gradient should also lead to pain sensitization and to a hyperekplexia phenotype that correlates with mutation severity, neither of which is observed in patients with GLRA1 hyperekplexia mutations. We also rule out small increases in IPSC decay times (as caused by W170S and R414H) as a possible mechanism given that the clinically important drug, tropisetron, significantly increases glycinergic IPSC decay times without causing motor side effects. A recent study on cultured spinal neurons concluded that an elevated intracellular chloride concentration late during development ablates α1β glycinergic synapses but spares GABAergic synapses. As this mechanism satisfies all our considerations, we propose it is primarily responsible for the hyperekplexia phenotype.
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Affiliation(s)
- Yan Zhang
- From the Queensland Brain Institute and
| | - Anna Bode
- From the Queensland Brain Institute and
| | | | | | - Joseph W Lynch
- From the Queensland Brain Institute and School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia 4072
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Voisin T, Bourinet E, Lory P. Genetic alteration of the metal/redox modulation of Cav3.2 T-type calcium channel reveals its role in neuronal excitability. J Physiol 2016; 594:3561-74. [PMID: 26931411 DOI: 10.1113/jp271925] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/29/2016] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS In this study, we describe a new knock-in (KI) mouse model that allows the study of the H191-dependent regulation of T-type Cav3.2 channels. Sensitivity to zinc, nickel and ascorbate of native Cav3.2 channels is significantly impeded in the dorsal root ganglion (DRG) neurons of this KI mouse. Importantly, we describe that this H191-dependent regulation has discrete but significant effects on the excitability properties of D-hair (down-hair) cells, a sub-population of DRG neurons in which Cav3.2 currents prominently regulate excitability. Overall, this study reveals that the native H191-dependent regulation of Cav3.2 channels plays a role in the excitability of Cav3.2-expressing neurons. This animal model will be valuable in addressing the potential in vivo roles of the trace metal and redox modulation of Cav3.2 T-type channels in a wide range of physiological and pathological conditions. ABSTRACT Cav3.2 channels are T-type voltage-gated calcium channels that play important roles in controlling neuronal excitability, particularly in dorsal root ganglion (DRG) neurons where they are involved in touch and pain signalling. Cav3.2 channels are modulated by low concentrations of metal ions (nickel, zinc) and redox agents, which involves the histidine 191 (H191) in the channel's extracellular IS3-IS4 loop. It is hypothesized that this metal/redox modulation would contribute to the tuning of the excitability properties of DRG neurons. However, the precise role of this H191-dependent modulation of Cav3.2 channel remains unresolved. Towards this goal, we have generated a knock-in (KI) mouse carrying the mutation H191Q in the Cav3.2 protein. Electrophysiological studies were performed on a subpopulation of DRG neurons, the D-hair cells, which express large Cav3.2 currents. We describe an impaired sensitivity to zinc, nickel and ascorbate of the T-type current in D-hair neurons from KI mice. Analysis of the action potential and low-threshold calcium spike (LTCS) properties revealed that, contrary to that observed in WT D-hair neurons, a low concentration of zinc and nickel is unable to modulate (1) the rheobase threshold current, (2) the afterdepolarization amplitude, (3) the threshold potential necessary to trigger an LTCS or (4) the LTCS amplitude in D-hair neurons from KI mice. Together, our data demonstrate that this H191-dependent metal/redox regulation of Cav3.2 channels can tune neuronal excitability. This study validates the use of this Cav3.2-H191Q mouse model for further investigations of the physiological roles thought to rely on this Cav3.2 modulation.
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Affiliation(s)
- Tiphaine Voisin
- Centre National pour la Recherche Scientifique UMR 5203, Département de Physiologie, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, F-34094, France.,Institut National de la Santé et de la Recherche Médicale, U 1191, Montpellier, F-34094, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, F-34094, France
| | - Emmanuel Bourinet
- Centre National pour la Recherche Scientifique UMR 5203, Département de Physiologie, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, F-34094, France.,Institut National de la Santé et de la Recherche Médicale, U 1191, Montpellier, F-34094, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, F-34094, France
| | - Philippe Lory
- Centre National pour la Recherche Scientifique UMR 5203, Département de Physiologie, Institut de Génomique Fonctionnelle, Université de Montpellier, Montpellier, F-34094, France.,Institut National de la Santé et de la Recherche Médicale, U 1191, Montpellier, F-34094, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, F-34094, France
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Dixon CL, Zhang Y, Lynch JW. Generation of Functional Inhibitory Synapses Incorporating Defined Combinations of GABA(A) or Glycine Receptor Subunits. Front Mol Neurosci 2015; 8:80. [PMID: 26778954 PMCID: PMC4688394 DOI: 10.3389/fnmol.2015.00080] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/07/2015] [Indexed: 11/13/2022] Open
Abstract
Fast inhibitory neurotransmission in the brain is mediated by wide range of GABAA receptor (GABAAR) and glycine receptor (GlyR) isoforms, each with different physiological and pharmacological properties. Because multiple isoforms are expressed simultaneously in most neurons, it is difficult to define the properties of individual isoforms under synaptic stimulation conditions in vivo. Although recombinant expression systems permit the expression of individual isoforms in isolation, they require exogenous agonist application which cannot mimic the dynamic neurotransmitter profile characteristic of native synapses. We describe a neuron-HEK293 cell co-culture technique for generating inhibitory synapses incorporating defined combinations of GABAAR or GlyR subunits. Primary neuronal cultures, prepared from embryonic rat cerebral cortex or spinal cord, are used to provide presynaptic GABAergic and glycinergic terminals, respectively. When the cultures are mature, HEK293 cells expressing the subunits of interest plus neuroligin 2A are plated onto the neurons, which rapidly form synapses onto HEK293 cells. Patch clamp electrophysiology is then used to analyze the physiological and pharmacological properties of the inhibitory postsynaptic currents mediated by the recombinant receptors. The method is suitable for investigating the kinetic properties or the effects of drugs on inhibitory postsynaptic currents mediated by defined GABAAR or GlyR isoforms of interest, the effects of hereditary disease mutations on the formation and function of both types of synapses, and synaptogenesis and synaptic clustering mechanisms. The entire cell preparation procedure takes 2-5 weeks.
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Affiliation(s)
- Christine L Dixon
- Queensland Brain Institute, University of Queensland Brisbane, QLD, Australia
| | - Yan Zhang
- Queensland Brain Institute, University of Queensland Brisbane, QLD, Australia
| | - Joseph W Lynch
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia; School of Biomedical Sciences, University of QueenslandBrisbane, QLD, Australia
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Kambe T, Tsuji T, Hashimoto A, Itsumura N. The Physiological, Biochemical, and Molecular Roles of Zinc Transporters in Zinc Homeostasis and Metabolism. Physiol Rev 2015; 95:749-84. [DOI: 10.1152/physrev.00035.2014] [Citation(s) in RCA: 556] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Zinc is involved in a variety of biological processes, as a structural, catalytic, and intracellular and intercellular signaling component. Thus zinc homeostasis is tightly controlled at the whole body, tissue, cellular, and subcellular levels by a number of proteins, with zinc transporters being particularly important. In metazoan, two zinc transporter families, Zn transporters (ZnT) and Zrt-, Irt-related proteins (ZIP) function in zinc mobilization of influx, efflux, and compartmentalization/sequestration across biological membranes. During the last two decades, significant progress has been made in understanding the molecular properties, expression, regulation, and cellular and physiological roles of ZnT and ZIP transporters, which underpin the multifarious functions of zinc. Moreover, growing evidence indicates that malfunctioning zinc homeostasis due to zinc transporter dysfunction results in the onset and progression of a variety of diseases. This review summarizes current progress in our understanding of each ZnT and ZIP transporter from the perspective of zinc physiology and pathogenesis, discussing challenging issues in their structure and zinc transport mechanisms.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tokuji Tsuji
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Ayako Hashimoto
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Naoya Itsumura
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Perez-Rosello T, Anderson CT, Ling C, Lippard SJ, Tzounopoulos T. Tonic zinc inhibits spontaneous firing in dorsal cochlear nucleus principal neurons by enhancing glycinergic neurotransmission. Neurobiol Dis 2015; 81:14-9. [PMID: 25796568 DOI: 10.1016/j.nbd.2015.03.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 03/02/2015] [Accepted: 03/12/2015] [Indexed: 12/18/2022] Open
Abstract
In many synapses of the CNS, mobile zinc is packaged into glutamatergic vesicles and co-released with glutamate during neurotransmission. Following synaptic release, the mobilized zinc modulates ligand- and voltage-gated channels and receptors, functioning as an inhibitory neuromodulator. However, the origin and role of tonic, as opposed to phasically released, zinc are less well understood. We investigated tonic zinc in the dorsal cochlear nucleus (DCN), a zinc-rich, auditory brainstem nucleus. Our results show that application of a high-affinity, extracellular zinc chelator (ZX1) enhances spontaneous firing in DCN principal neurons (fusiform cells), consistent with inhibition of this neuronal property by tonic zinc. The enhancing effect was prevented by prior application of strychnine, a glycine receptor antagonist, suggesting that ZX1 interferes with zinc-mediated modulation of spontaneous glycinergic inhibition. In particular, ZX1 decreased the amplitude and the frequency of glycinergic miniature inhibitory postsynaptic currents in fusiform cells, from which we conclude that tonic zinc enhances glycinergic inhibitory neurotransmission. The observed zinc-mediated inhibition in spontaneous firing is present in mice lacking the vesicular zinc transporter (ZnT3), indicating that non-vesicular zinc inhibits spontaneous firing. Noise-induced increase in the spontaneous firing of fusiform cells is crucial for the induction of tinnitus. In this context, tonic zinc provides a powerful break of spontaneous firing that may protect against pathological run-up of spontaneous activity in the DCN.
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Affiliation(s)
- Tamara Perez-Rosello
- Department of Otolaryngology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Charles T Anderson
- Department of Otolaryngology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Cindy Ling
- Department of Otolaryngology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA
| | - Stephen J Lippard
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Thanos Tzounopoulos
- Department of Otolaryngology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA.
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Zhang Y, Dixon CL, Keramidas A, Lynch JW. Functional reconstitution of glycinergic synapses incorporating defined glycine receptor subunit combinations. Neuropharmacology 2015; 89:391-7. [DOI: 10.1016/j.neuropharm.2014.10.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/16/2014] [Accepted: 10/26/2014] [Indexed: 10/24/2022]
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: ligand-gated ion channels. Br J Pharmacol 2014; 170:1582-606. [PMID: 24528238 PMCID: PMC3892288 DOI: 10.1111/bph.12446] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. Ligand-gated ion channels are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen P H Alexander
- School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
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Stojilkovic SS, Leiva-Salcedo E, Rokic MB, Coddou C. Regulation of ATP-gated P2X channels: from redox signaling to interactions with other proteins. Antioxid Redox Signal 2014; 21:953-70. [PMID: 23944253 PMCID: PMC4116155 DOI: 10.1089/ars.2013.5549] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE The family of purinergic P2X receptors (P2XRs) is a part of ligand-gated superfamily of channels activated by extracellular adenosine-5'-triphosphate. P2XRs are present in virtually all mammalian tissues as well as in tissues of other vertebrate and nonvertebrate species and mediate a large variety of functions, including fast transmission at central synapses, contraction of smooth muscle cells, platelet aggregation, and macrophage activation to proliferation and cell death. RECENT ADVANCES The recent solving of crystal structure of the zebrafish P2X4.1R is a major advance in the understanding of structural correlates of channel activation and regulation. Combined with growing information obtained in the post-structure era and the reinterpretation of previous work within the context of the tridimensional structure, these data provide a better understanding of how the channel operates at the molecular levels. CRITICAL ISSUES This review focuses on the relationship between redox signaling and P2XR function. We also discuss other allosteric modulation of P2XR gating in the physiological/pathophysiological context. This includes the summary of extracellular actions of trace metals, which can be released to the synaptic cleft, pH decrease that happens during ischemia and inflammation, and calcium, an extracellular and intracellular messenger. FUTURE DIRECTIONS Our evolving understanding of activation and regulation of P2XRs is helpful in clarifying the mechanism by which these channels trigger and modulate cellular functions. Further research is required to identify the signaling pathways contributing to the regulation of the receptor activity and to develop novel and receptor-specific allosteric modulators, which could be used in vivo with therapeutic potential.
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Affiliation(s)
- Stanko S Stojilkovic
- 1 Section on Cellular Signaling, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health , Bethesda, Maryland
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Schaefer N, Langlhofer G, Kluck CJ, Villmann C. Glycine receptor mouse mutants: model systems for human hyperekplexia. Br J Pharmacol 2014; 170:933-52. [PMID: 23941355 DOI: 10.1111/bph.12335] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 07/19/2013] [Accepted: 08/02/2013] [Indexed: 11/30/2022] Open
Abstract
Human hyperekplexia is a neuromotor disorder caused by disturbances in inhibitory glycine-mediated neurotransmission. Mutations in genes encoding for glycine receptor subunits or associated proteins, such as GLRA1, GLRB, GPHN and ARHGEF9, have been detected in patients suffering from hyperekplexia. Classical symptoms are exaggerated startle attacks upon unexpected acoustic or tactile stimuli, massive tremor, loss of postural control during startle and apnoea. Usually patients are treated with clonazepam, this helps to dampen the severe symptoms most probably by up-regulating GABAergic responses. However, the mechanism is not completely understood. Similar neuromotor phenotypes have been observed in mouse models that carry glycine receptor mutations. These mouse models serve as excellent tools for analysing the underlying pathomechanisms. Yet, studies in mutant mice looking for postsynaptic compensation of glycinergic dysfunction via an up-regulation in GABAA receptor numbers have failed, as expression levels were similar to those in wild-type mice. However, presynaptic adaptation mechanisms with an unusual switch from mixed GABA/glycinergic to GABAergic presynaptic terminals have been observed. Whether this presynaptic adaptation explains the improvement in symptoms or other compensation mechanisms exist is still under investigation. With the help of spontaneous glycine receptor mouse mutants, knock-in and knock-out studies, it is possible to associate behavioural changes with pharmacological differences in glycinergic inhibition. This review focuses on the structural and functional characteristics of the various mouse models used to elucidate the underlying signal transduction pathways and adaptation processes and describes a novel route that uses gene-therapeutic modulation of mutated receptors to overcome loss of function mutations.
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Affiliation(s)
- Natascha Schaefer
- Institute for Clinical Neurobiology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
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Bode A, Lynch JW. The impact of human hyperekplexia mutations on glycine receptor structure and function. Mol Brain 2014; 7:2. [PMID: 24405574 PMCID: PMC3895786 DOI: 10.1186/1756-6606-7-2] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/07/2014] [Indexed: 01/11/2023] Open
Abstract
Hyperekplexia is a rare neurological disorder characterized by neonatal hypertonia, exaggerated startle responses to unexpected stimuli and a variable incidence of apnoea, intellectual disability and delays in speech acquisition. The majority of motor defects are successfully treated by clonazepam. Hyperekplexia is caused by hereditary mutations that disrupt the functioning of inhibitory glycinergic synapses in neuromotor pathways of the spinal cord and brainstem. The human glycine receptor α1 and β subunits, which predominate at these synapses, are the major targets of mutations. International genetic screening programs, that together have analysed several hundred probands, have recently generated a clear picture of genotype-phenotype correlations and the prevalence of different categories of hyperekplexia mutations. Focusing largely on this new information, this review seeks to summarise the effects of mutations on glycine receptor structure and function and how these functional alterations lead to hyperekplexia.
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Affiliation(s)
| | - Joseph W Lynch
- Queensland Brain Institute and School of Biomedical Sciences, The University of Queensland, Queensland 4072, Australia.
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The GLRA1 missense mutation W170S associates lack of Zn2+ potentiation with human hyperekplexia. J Neurosci 2013; 33:17675-81. [PMID: 24198360 DOI: 10.1523/jneurosci.3240-13.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hyperekplexia is a neurological disorder associated primarily with mutations in the α1 subunit of glycine receptors (GlyRs) that lead to dysfunction of glycinergic inhibitory transmission. To date, most of the identified mutations result in disruption of surface expression or altered channel properties of α1-containing GlyRs. Little evidence has emerged to support an involvement of allosteric GlyR modulation in human hyperekplexia. Here, we report that recombinant human GlyRs containing α1 or α1β subunits with a missense mutation in the α1 subunit (W170S), previously identified from familial hyperekplexia, caused remarkably reduced potentiation and enhanced inhibition by Zn(2+). Interestingly, mutant α1(W170S)β GlyRs displayed no significant changes in potency or maximum response to glycine, taurine, or β-alanine. By temporally separating the potentiating and the inhibitory effects of Zn(2+), we found that the enhancement of Zn(2+) inhibition resulted from a loss of Zn(2+)-mediated potentiation. The W170S mutation on the background of H107N, which was previously reported to selectively disrupt Zn(2+) inhibition, showed remarkable attenuation of Zn(2+)-mediated potentiation and thus indicated that W170 is an important residue for the Zn(2+)-mediated GlyR potentiation. Moreover, overexpressing the α1(W170S) subunit in cultured rat neurons confirmed the results from heterologous expression. Together, our results reveal a new zinc potentiation site on α1 GlyRs and a strong link between Zn(2+) modulation and human disease.
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Lynagh T, Kunz A, Laube B. Propofol modulation of α1 glycine receptors does not require a structural transition at adjacent subunits that is crucial to agonist-induced activation. ACS Chem Neurosci 2013; 4:1469-78. [PMID: 23992940 DOI: 10.1021/cn400134p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Pentameric glycine receptors (GlyRs) couple agonist binding to activation of an intrinsic ion channel. Substitution of the R271 residue impairs agonist-induced activation and is associated with the human disease hyperekplexia. On the basis of a homology model of the α1 GlyR, we substituted residues in the vicinity of R271 with cysteines, generating R271C, Q226C, and D284C single-mutant GlyRs and R271C/Q226C and R271C/D284C double-mutant GlyRs. We then examined the impact of interactions between these positions on receptor activation by glycine and modulation by the anesthetic propofol, as measured by electrophysiological experiments. Upon expression in Xenopus laevis oocytes, D284C-containing receptors were nonfunctional, despite biochemical evidence of successful cell surface expression. At R271C/Q226C GlyRs, glycine-activated whole-cell currents were increased 3-fold in the presence of the thiol reductant dithiothreitol, whereas the ability of propofol to enhance glycine-activated currents was not affected by dithiothreitol. Biochemical experiments showed that mutant R271C/Q226C subunits form covalently linked pentamers, showing that intersubunit disulfide cross-links are formed. These data indicate that intersubunit disulfide links in the transmembrane domain prevent a structural transition that is crucial to agonist-induced activation of GlyRs but not to modulation by the anesthetic propofol and implicate D284 in the functional integrity of GlyRs.
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Affiliation(s)
- Timothy Lynagh
- Neurophysiology and Neurosensory Systems, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany
| | - Alexander Kunz
- Neurophysiology and Neurosensory Systems, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany
| | - Bodo Laube
- Neurophysiology and Neurosensory Systems, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany
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Abstract
Although it is well established that many glutamatergic neurons sequester Zn(2+) within their synaptic vesicles, the physiological significance of synaptic Zn(2+) remains poorly understood. In experiments performed in a Zn(2+)-enriched auditory brainstem nucleus--the dorsal cochlear nucleus--we discovered that synaptic Zn(2+) and GPR39, a putative metabotropic Zn(2+)-sensing receptor (mZnR), are necessary for triggering the synthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). The postsynaptic production of 2-AG, in turn, inhibits presynaptic probability of neurotransmitter release, thus shaping synaptic strength and short-term synaptic plasticity. Zn(2+)-induced inhibition of transmitter release is absent in mutant mice that lack either vesicular Zn(2+) or the mZnR. Moreover, mass spectrometry measurements of 2-AG levels reveal that Zn(2+)-mediated initiation of 2-AG synthesis is absent in mice lacking the mZnR. We reveal a previously unknown action of synaptic Zn(2+): synaptic Zn(2+) inhibits glutamate release by promoting 2-AG synthesis.
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Rahman J, Latal AT, Besser S, Hirrlinger J, Hülsmann S. Mixed miniature postsynaptic currents resulting from co-release of glycine and GABA recorded from glycinergic neurons in the neonatal respiratory network. Eur J Neurosci 2013; 37:1229-41. [DOI: 10.1111/ejn.12136] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 12/28/2022]
Affiliation(s)
| | - A. Tobias Latal
- DFG Research Center for Molecular Physiology of the Brain (CMPB); University of Göttingen; Göttingen; Germany
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McCracken LM, Blednov YA, Trudell JR, Benavidez JM, Betz H, Harris RA. Mutation of a zinc-binding residue in the glycine receptor α1 subunit changes ethanol sensitivity in vitro and alcohol consumption in vivo. J Pharmacol Exp Ther 2012; 344:489-500. [PMID: 23230213 DOI: 10.1124/jpet.112.197707] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ethanol is a widely used drug, yet an understanding of its sites and mechanisms of action remains incomplete. Among the protein targets of ethanol are glycine receptors (GlyRs), which are potentiated by millimolar concentrations of ethanol. In addition, zinc ions also modulate GlyR function, and recent evidence suggests that physiologic concentrations of zinc enhance ethanol potentiation of GlyRs. Here, we first built a homology model of a zinc-bound GlyR using the D80 position as a coordination site for a zinc ion. Next, we investigated in vitro the effects of zinc on ethanol action at recombinant wild-type (WT) and mutant α1 GlyRs containing the D80A substitution, which eliminates zinc potentiation. At D80A GlyRs, the effects of 50 and 200 mM ethanol were reduced as compared with WT receptors. Also, in contrast to what was seen with WT GlyRs, neither adding nor chelating zinc changed the magnitude of ethanol enhancement of mutant D80A receptors. Next, we evaluated the in vivo effects of the D80A substitution by using heterozygous Glra1(D80A) knock-in (KI) mice. The KI mice showed decreased ethanol consumption and preference, and they displayed increased startle responses compared with their WT littermates. Other behavioral tests, including ethanol-induced motor incoordination and strychnine-induced convulsions, revealed no differences between the KI and WT mice. Together, our findings indicate that zinc is critical in determining the effects of ethanol at GlyRs and suggest that zinc binding at the D80 position may be important for mediating some of the behavioral effects of ethanol action at GlyRs.
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Affiliation(s)
- Lindsay M McCracken
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
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Abstract
Strychnine-sensitive glycine receptors (GlyRs) mediate synaptic inhibition in the spinal cord, brainstem, and other regions of the mammalian central nervous system. In this minireview, we summarize our current view of the structure, ligand-binding sites, and chloride channel of these receptors and discuss recently emerging functions of distinct GlyR isoforms. GlyRs not only regulate the excitability of motor and afferent sensory neurons, including pain fibers, but also are involved in the processing of visual and auditory signals. Hence, GlyRs constitute promising targets for the development of therapeutically useful compounds.
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Affiliation(s)
- Sébastien Dutertre
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Cord-Michael Becker
- the Institute of Biochemistry, University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Heinrich Betz
- the Max-Planck-Institute for Medical Research, 69120 Heidelberg, Germany, and
- the Department of Molecular Neurobiology, Max-Planck-Institute for Experimental Medicine, 37075 Göttingen, Germany
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48
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Schaefer N, Vogel N, Villmann C. Glycine receptor mutants of the mouse: what are possible routes of inhibitory compensation? Front Mol Neurosci 2012; 5:98. [PMID: 23118727 PMCID: PMC3484359 DOI: 10.3389/fnmol.2012.00098] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 10/11/2012] [Indexed: 12/02/2022] Open
Abstract
Defects in glycinergic inhibition result in a complex neuromotor disorder in humans known as hyperekplexia (OMIM 149400) with similar phenotypes in rodents characterized by an exaggerated startle reflex and hypertonia. Analogous to genetic defects in humans single point mutations, microdeletions, or insertions in the Glra1 gene but also in the Glrb gene underlie the pathology in mice. The mutations either localized in the α (spasmodic, oscillator, cincinnati, Nmf11) or the β (spastic) subunit of the glycine receptor (GlyR) are much less tolerated in mice than in humans, leaving the question for the existence of different regulatory elements of the pathomechanisms in humans and rodents. In addition to the spontaneous mutations, new insights into understanding of the regulatory pathways in hyperekplexia or glycine encephalopathy arose from the constantly increasing number of knock-out as well as knock-in mutants of GlyRs. Over the last five years, various efforts using in vivo whole cell recordings provided a detailed analysis of the kinetic parameters underlying glycinergic dysfunction. Presynaptic compensation as well as postsynaptic compensatory mechanisms in these mice by other GlyR subunits or GABAA receptors, and the role of extra-synaptic GlyRs is still a matter of debate. A recent study on the mouse mutant oscillator displayed a novel aspect for compensation of functionality by complementation of receptor domains that fold independently. This review focuses on defects in glycinergic neurotransmission in mice discussed with the background of human hyperekplexia en route to strategies of compensation.
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Affiliation(s)
- Natascha Schaefer
- Emil Fischer Center, Institute of Biochemistry, University Erlangen-Nuernberg Erlangen, Germany ; Institute for Clinical Neurobiology, University of Wuerzburg Wuerzburg, Germany
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Giménez C, Pérez-Siles G, Martínez-Villarreal J, Arribas-González E, Jiménez E, Núñez E, de Juan-Sanz J, Fernández-Sánchez E, García-Tardón N, Ibáñez I, Romanelli V, Nevado J, James VM, Topf M, Chung SK, Thomas RH, Desviat LR, Aragón C, Zafra F, Rees MI, Lapunzina P, Harvey RJ, López-Corcuera B. A novel dominant hyperekplexia mutation Y705C alters trafficking and biochemical properties of the presynaptic glycine transporter GlyT2. J Biol Chem 2012; 287:28986-9002. [PMID: 22753417 PMCID: PMC3436537 DOI: 10.1074/jbc.m111.319244] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 06/18/2012] [Indexed: 11/06/2022] Open
Abstract
Hyperekplexia or startle disease is characterized by an exaggerated startle response, evoked by tactile or auditory stimuli, producing hypertonia and apnea episodes. Although rare, this orphan disorder can have serious consequences, including sudden infant death. Dominant and recessive mutations in the human glycine receptor (GlyR) α1 gene (GLRA1) are the major cause of this disorder. However, recessive mutations in the presynaptic Na(+)/Cl(-)-dependent glycine transporter GlyT2 gene (SLC6A5) are rapidly emerging as a second major cause of startle disease. In this study, systematic DNA sequencing of SLC6A5 revealed a new dominant GlyT2 mutation: pY705C (c.2114A→G) in transmembrane domain 11, in eight individuals from Spain and the United Kingdom. Curiously, individuals harboring this mutation show significant variation in clinical presentation. In addition to classical hyperekplexia symptoms, some individuals had abnormal respiration, facial dysmorphism, delayed motor development, or intellectual disability. We functionally characterized this mutation using molecular modeling, electrophysiology, [(3)H]glycine transport, cell surface expression, and cysteine labeling assays. We found that the introduced cysteine interacts with the cysteine pair Cys-311-Cys-320 in the second external loop of GlyT2. This interaction impairs transporter maturation through the secretory pathway, reduces surface expression, and inhibits transport function. Additionally, Y705C presents altered H(+) and Zn(2+) dependence of glycine transport that may affect the function of glycinergic neurotransmission in vivo.
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Affiliation(s)
- Cecilio Giménez
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Gonzalo Pérez-Siles
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Jaime Martínez-Villarreal
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Esther Arribas-González
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Esperanza Jiménez
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Enrique Núñez
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Jaime de Juan-Sanz
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Enrique Fernández-Sánchez
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
| | - Noemí García-Tardón
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Ignacio Ibáñez
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
| | - Valeria Romanelli
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the Instituto de Genética Médica y Molecular, IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid 28046, Spain
| | - Julián Nevado
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the Instituto de Genética Médica y Molecular, IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid 28046, Spain
| | - Victoria M. James
- the Department of Pharmacology, University College London School of Pharmacy, London WC1N 1AX, United Kingdom
| | - Maya Topf
- the Institute of Structural and Molecular Biology, Crystallography, Birkbeck College, London WC1E 7HX, United Kingdom, and
| | - Seo-Kyung Chung
- the Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, United Kingdom
| | - Rhys H. Thomas
- the Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, United Kingdom
| | - Lourdes R. Desviat
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
| | - Carmen Aragón
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Francisco Zafra
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
| | - Mark I. Rees
- the Institute of Life Science, College of Medicine, Swansea University, Swansea SA2 8PP, United Kingdom
| | - Pablo Lapunzina
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the Instituto de Genética Médica y Molecular, IdiPAZ-Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid 28046, Spain
| | - Robert J. Harvey
- the Department of Pharmacology, University College London School of Pharmacy, London WC1N 1AX, United Kingdom
| | - Beatriz López-Corcuera
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Madrid 28049, Spain
- the Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, Madrid 28029, Spain
- the IdiPAZ-Hospital Universitario La Paz
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50
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Frazzini V. Synaptic physiology revised: think zinc! FUTURE NEUROLOGY 2012. [DOI: 10.2217/fnl.12.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The last few years have seen a dramatic increase in our understanding of the Zn2+ modulatory role in the physiological functioning of the CNS. The availability of new experimental tools, such as the combination of new microscopy techniques with electrophysiological recordings, along with new selective fluorescent probes and chelators has started a revolution in Zn2+ neurobiology. Zn2+ has emerged as a versatile signaling molecule involved in numerous critical neuronal functions spanning from synaptic transmission and plasticity to neuronal differentiation and death.
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Affiliation(s)
- Valerio Frazzini
- Molecular Neurology Unit, Center of Excellence on Aging (Ce.S.I.), University G. D’Annunzio, Chieti-Pescara, Italy
- Department of Neuroscience & Imaging, University G. D’Annunzio, Chieti-Pescara, Italy
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