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Asakawa K, Handa H, Kawakami K. Multi-phaseted problems of TDP-43 in selective neuronal vulnerability in ALS. Cell Mol Life Sci 2021; 78:4453-4465. [PMID: 33709256 PMCID: PMC8195926 DOI: 10.1007/s00018-021-03792-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/03/2021] [Accepted: 02/18/2021] [Indexed: 10/28/2022]
Abstract
Transactive response DNA-binding protein 43 kDa (TDP-43) encoded by the TARDBP gene is an evolutionarily conserved heterogeneous nuclear ribonucleoprotein (hnRNP) that regulates multiple steps of RNA metabolism, and its cytoplasmic aggregation characterizes degenerating motor neurons in amyotrophic lateral sclerosis (ALS). In most ALS cases, cytoplasmic TDP-43 aggregation occurs in the absence of mutations in the coding sequence of TARDBP. Thus, a major challenge in ALS research is to understand the nature of pathological changes occurring in wild-type TDP-43 and to explore upstream events in intracellular and extracellular milieu that promote the pathological transition of TDP-43. Despite the inherent obstacles to analyzing TDP-43 dynamics in in vivo motor neurons due to their anatomical complexity and inaccessibility, recent studies using cellular and animal models have provided important mechanistic insights into potential links between TDP-43 and motor neuron vulnerability in ALS. This review is intended to provide an overview of the current literature on the function and regulation of TDP-43-containing RNP granules or membraneless organelles, as revealed by various models, and to discuss the potential mechanisms by which TDP-43 can cause selective vulnerability of motor neurons in ALS.
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Affiliation(s)
- Kazuhide Asakawa
- Department of Chemical Biology, Tokyo Medical University, Shinjuku-ku, Tokyo, 160-8402, Japan.
- Division of Molecular and Developmental Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
| | - Hiroshi Handa
- Department of Chemical Biology, Tokyo Medical University, Shinjuku-ku, Tokyo, 160-8402, Japan
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
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2
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Jordan K, Murphy J, Singh A, Mitchell CS. Astrocyte-Mediated Neuromodulatory Regulation in Preclinical ALS: A Metadata Analysis. Front Cell Neurosci 2018; 12:491. [PMID: 30618638 PMCID: PMC6305074 DOI: 10.3389/fncel.2018.00491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 11/29/2018] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by progressive degradation of motoneurons in the central nervous system (CNS). Astrocytes are key regulators for inflammation and neuromodulatory signaling, both of which contribute to ALS. The study goal was to ascertain potential temporal changes in astrocyte-mediated neuromodulatory regulation with transgenic ALS model progression: glutamate, GTL-1, GluR1, GluR2, GABA, ChAT activity, VGF, TNFα, aspartate, and IGF-1. We examine neuromodulatory changes in data aggregates from 42 peer-reviewed studies derived from transgenic ALS mixed cell cultures (neurons + astrocytes). For each corresponding experimental time point, the ratio of transgenic to wild type (WT) was found for each compound. ANOVA and a student's t-test were performed to compare disease stages (early, post-onset, and end stage). Glutamate in transgenic SOD1-G93A mixed cell cultures does not change over time (p > 0.05). GLT-1 levels were found to be decreased 23% over WT but only at end-stage (p < 0.05). Glutamate receptors (GluR1, GluR2) in SOD1-G93A were not substantially different from WT, although SOD1-G93A GluR1 decreased by 21% from post-onset to end-stage (p < 0.05). ChAT activity was insignificantly decreased. VGF is decreased throughout ALS (p < 0.05). Aspartate is elevated by 25% in SOD1-G93A but only during end-stage (p < 0.05). TNFα is increased by a dramatic 362% (p < 0.05). Furthermore, principal component analysis identified TNFα as contributing to 55% of the data variance in the first component. Thus, TNFα, which modulates astrocyte regulation via multiple pathways, could be a strategic treatment target. Overall results suggest changes in neuromodulator levels are subtle in SOD1-G93A ALS mixed cell cultures. If excitotoxicity is present as is often presumed, it could be due to ALS cells being more sensitive to small changes in neuromodulation. Hence, seemingly unsubstantial or oscillatory changes in neuromodulators could wreak havoc in ALS cells, resulting in failed microenvironment homeostasis whereby both hyperexcitability and hypoexcitability can coexist. Future work is needed to examine local, spatiotemporal neuromodulatory homeostasis and assess its functional impact in ALS.
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Affiliation(s)
- Kathleen Jordan
- Laboratory for Pathology Dynamics, Department of Biomedical Engineering, Georgia Institute of Technology, Emory University School of Medicine, Atlanta, GA, United States
| | - Joseph Murphy
- Laboratory for Pathology Dynamics, Department of Biomedical Engineering, Georgia Institute of Technology, Emory University School of Medicine, Atlanta, GA, United States
| | - Anjanya Singh
- Laboratory for Pathology Dynamics, Department of Biomedical Engineering, Georgia Institute of Technology, Emory University School of Medicine, Atlanta, GA, United States
- School of Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Cassie S. Mitchell
- Laboratory for Pathology Dynamics, Department of Biomedical Engineering, Georgia Institute of Technology, Emory University School of Medicine, Atlanta, GA, United States
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3
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Selvaraj BT, Livesey MR, Zhao C, Gregory JM, James OT, Cleary EM, Chouhan AK, Gane AB, Perkins EM, Dando O, Lillico SG, Lee YB, Nishimura AL, Poreci U, Thankamony S, Pray M, Vasistha NA, Magnani D, Borooah S, Burr K, Story D, McCampbell A, Shaw CE, Kind PC, Aitman TJ, Whitelaw CBA, Wilmut I, Smith C, Miles GB, Hardingham GE, Wyllie DJA, Chandran S. C9ORF72 repeat expansion causes vulnerability of motor neurons to Ca 2+-permeable AMPA receptor-mediated excitotoxicity. Nat Commun 2018; 9:347. [PMID: 29367641 PMCID: PMC5783946 DOI: 10.1038/s41467-017-02729-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 12/21/2017] [Indexed: 12/13/2022] Open
Abstract
Mutations in C9ORF72 are the most common cause of familial amyotrophic lateral sclerosis (ALS). Here, through a combination of RNA-Seq and electrophysiological studies on induced pluripotent stem cell (iPSC)-derived motor neurons (MNs), we show that increased expression of GluA1 AMPA receptor (AMPAR) subunit occurs in MNs with C9ORF72 mutations that leads to increased Ca2+-permeable AMPAR expression and results in enhanced selective MN vulnerability to excitotoxicity. These deficits are not found in iPSC-derived cortical neurons and are abolished by CRISPR/Cas9-mediated correction of the C9ORF72 repeat expansion in MNs. We also demonstrate that MN-specific dysregulation of AMPAR expression is also present in C9ORF72 patient post-mortem material. We therefore present multiple lines of evidence for the specific upregulation of GluA1 subunits in human mutant C9ORF72 MNs that could lead to a potential pathogenic excitotoxic mechanism in ALS. Repeat expansion mutation in C9ORF72 is the most common cause of familial ALS. Here, the authors generate motor neurons from cells of patients with C9ORF72 mutations, and characterize changes in gene expression in these motor neurons compared to genetically corrected lines, which suggest that glutamate receptor subunit GluA1 is dysregulated in this form of ALS.
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Affiliation(s)
- Bhuvaneish T Selvaraj
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Matthew R Livesey
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Chen Zhao
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Jenna M Gregory
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Owain T James
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Elaine M Cleary
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Amit K Chouhan
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, KY16 9JP, UK
| | - Angus B Gane
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Emma M Perkins
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Owen Dando
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.,Centre for Brain Development and Repair, inStem, Bangalore, 560065, India
| | - Simon G Lillico
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Youn-Bok Lee
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 8AF, UK
| | - Agnes L Nishimura
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 8AF, UK
| | - Urjana Poreci
- Global Biomarker and Drug Discovery, Biogen, Cambridge, MA, 02142, USA
| | - Sai Thankamony
- Global Biomarker and Drug Discovery, Biogen, Cambridge, MA, 02142, USA
| | - Meryll Pray
- Global Biomarker and Drug Discovery, Biogen, Cambridge, MA, 02142, USA
| | - Navneet A Vasistha
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Brain Development and Repair, inStem, Bangalore, 560065, India
| | - Dario Magnani
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Shyamanga Borooah
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Karen Burr
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - David Story
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | | | - Christopher E Shaw
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 8AF, UK
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.,Centre for Brain Development and Repair, inStem, Bangalore, 560065, India
| | - Timothy J Aitman
- MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - C Bruce A Whitelaw
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Ian Wilmut
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Colin Smith
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Gareth B Miles
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, KY16 9JP, UK
| | - Giles E Hardingham
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.,UK DRI Institute at Edinburgh, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - David J A Wyllie
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK. .,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK. .,Centre for Brain Development and Repair, inStem, Bangalore, 560065, India.
| | - Siddharthan Chandran
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK. .,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, EH16 4SB, UK. .,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK. .,Centre for Brain Development and Repair, inStem, Bangalore, 560065, India. .,UK DRI Institute at Edinburgh, University of Edinburgh, Edinburgh, EH16 4UU, UK.
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4
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Canto-Bustos M, Loeza-Alcocer E, Cuellar CA, Osuna P, Elias-Viñas D, Granados-Soto V, Manjarrez E, Felix R, Delgado-Lezama R. Tonically Active α 5GABA A Receptors Reduce Motoneuron Excitability and Decrease the Monosynaptic Reflex. Front Cell Neurosci 2017; 11:283. [PMID: 28970784 PMCID: PMC5609539 DOI: 10.3389/fncel.2017.00283] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/31/2017] [Indexed: 11/19/2022] Open
Abstract
Motoneurons, the final common path of the Central Nervous System (CNS), are under a complex control of its excitability in order to precisely translate the interneuronal pattern of activity into skeletal muscle contraction and relaxation. To fulfill this relevant function, motoneurons are provided with a vast repertoire of receptors and channels, including the extrasynaptic GABAA receptors which have been poorly investigated. Here, we confirmed that extrasynaptic α5 subunit-containing GABAA receptors localize with choline acetyltransferase (ChAT) positive cells, suggesting that these receptors are expressed in turtle motoneurons as previously reported in rodents. In these cells, α5GABAA receptors are activated by ambient GABA, producing a tonic shunt that reduces motoneurons’ membrane resistance and affects their action potential firing properties. In addition, α5GABAA receptors shunted the synaptic excitatory inputs depressing the monosynaptic reflex (MSR) induced by activation of primary afferents. Therefore, our results suggest that α5GABAA receptors may play a relevant physiological role in motor control.
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Affiliation(s)
- Martha Canto-Bustos
- Department of Neuroscience, Center for the Neural Basis of Cognition, University of PittsburghPittsburgh, PA, United States
| | - Emanuel Loeza-Alcocer
- Department of Neurobiology, University of Pittsburgh School of MedicinePittsburgh, PA, United States
| | - Carlos A Cuellar
- Laboratory of Neuronal Engineering, Mayo Clinic MinnesotaRochester, MN, United States
| | - Paulina Osuna
- Departamento de Fisiología, Biofísica y Neurociencias, CinvestavMexico City, Mexico
| | | | | | - Elías Manjarrez
- Instituto de Fisiología, Benemérita Universidad Autónoma de PueblaPuebla, Mexico
| | - Ricardo Felix
- Departamento de Biología Celular, CinvestavMexico City, Mexico
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5
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Körner S, Böselt S, Wichmann K, Thau-Habermann N, Zapf A, Knippenberg S, Dengler R, Petri S. The Axon Guidance Protein Semaphorin 3A Is Increased in the Motor Cortex of Patients With Amyotrophic Lateral Sclerosis. J Neuropathol Exp Neurol 2016; 75:326-333. [PMID: 26921371 DOI: 10.1093/jnen/nlw003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disorder that leads to progressive paralysis of skeletal muscles and death by respiratory failure. There is increasing evidence that ALS is at least in part an axonopathy and that mechanisms regulating axonal degeneration and regeneration might be pathogenetically relevant. Semaphorin 3A (Sema3A) is an axon guidance protein; it acts as an axon repellent and prevents axonal regeneration. Increased Sema3A expression has been described in a mouse model of ALS in which it may contribute to motor neuron degeneration. This study aimed to investigate Sema3A mRNA and protein expression in human CNS tissues. We assessed Sema3A expression using quantitative real-time PCR, in situ hybridization, and immunohistochemistry in motor cortex and spinal cord tissue of 8 ALS patients and 6 controls. We found a consistent increase of Sema3A expression in the motor cortex of ALS patients by all 3 methods. In situ hybridization further confirmed that Sema3A expression was present in motor neurons. These findings indicate that upregulation of Sema3A may contribute to axonal degeneration and failure of regeneration in ALS patients. The inhibition of Sema3A therefore might be a promising future therapeutic option for patients with this disease.
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Affiliation(s)
- Sonja Körner
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP).
| | - Sebastian Böselt
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
| | - Klaudia Wichmann
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
| | - Nadine Thau-Habermann
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
| | - Antonia Zapf
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
| | - Sarah Knippenberg
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
| | - Reinhard Dengler
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
| | - Susanne Petri
- From the Department of Neurology, Hannover Medical School, Hannover, Germany (SK, SB, KW, NTH, RD); Department of Medical Statistics, University Medical Center, Göttingen, Germany (AZ); Department of Experimental Pneumology, Hannover Medical School, Hannover, Germany (SK); and Center for Systems Neuroscience (ZSN), Hannover, Germany (RD, SP)
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6
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King AE, Woodhouse A, Kirkcaldie MT, Vickers JC. Excitotoxicity in ALS: Overstimulation, or overreaction? Exp Neurol 2016; 275 Pt 1:162-71. [DOI: 10.1016/j.expneurol.2015.09.019] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/30/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022]
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7
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Andres C, Aguilar J, González-Ramírez R, Elias-Viñas D, Felix R, Delgado-Lezama R. Extrasynaptic α6 subunit-containing GABAA receptors modulate excitability in turtle spinal motoneurons. PLoS One 2014; 9:e115378. [PMID: 25531288 PMCID: PMC4274054 DOI: 10.1371/journal.pone.0115378] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/22/2014] [Indexed: 11/22/2022] Open
Abstract
Motoneurons are furnished with a vast repertoire of ionotropic and metabotropic receptors as well as ion channels responsible for maintaining the resting membrane potential and involved in the regulation of the mechanisms underlying its membrane excitability and firing properties. Among them, the GABAA receptors, which respond to GABA binding by allowing the flow of Cl− ions across the membrane, mediate two distinct forms of inhibition in the mature nervous system, phasic and tonic, upon activation of synaptic or extrasynaptic receptors, respectively. In a previous work we showed that furosemide facilitates the monosynaptic reflex without affecting the dorsal root potential. Our data also revealed a tonic inhibition mediated by GABAA receptors activated in motoneurons by ambient GABA. These data suggested that the high affinity GABAA extrasynaptic receptors may have an important role in motor control, though the molecular nature of these receptors was not determined. By combining electrophysiological, immunofluorescence and molecular biology techniques with pharmacological tools here we show that GABAA receptors containing the α6 subunit are expressed in adult turtle spinal motoneurons and can function as extrasynaptic receptors responsible for tonic inhibition. These results expand our understanding of the role of GABAA receptors in motoneuron tonic inhibition.
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Affiliation(s)
- Carmen Andres
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), México DF, México
| | - Justo Aguilar
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), México DF, México
| | - Ricardo González-Ramírez
- Departamento de Biología Molecular e Histocompatibilidad, Hospital General “Dr. Manuel Gea González,” México DF, México
| | | | - Ricardo Felix
- Departamento de Biología Celular, Cinvestav-IPN, México DF, México
| | - Rodolfo Delgado-Lezama
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), México DF, México
- * E-mail:
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8
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de Oliveira GP, Alves CJ, Chadi G. Early gene expression changes in spinal cord from SOD1(G93A) Amyotrophic Lateral Sclerosis animal model. Front Cell Neurosci 2013; 7:216. [PMID: 24302897 PMCID: PMC3831149 DOI: 10.3389/fncel.2013.00216] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/29/2013] [Indexed: 11/13/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is an adult-onset and fast progression neurodegenerative disease that leads to the loss of motor neurons. Mechanisms of selective motor neuron loss in ALS are unknown. The early events occurring in the spinal cord that may contribute to motor neuron death are not described, neither astrocytes participation in the pre-symptomatic phases of the disease. In order to identify ALS early events, we performed a microarray analysis employing a whole mouse genome platform to evaluate the gene expression pattern of lumbar spinal cords of transgenic SOD1G93A mice and their littermate controls at pre-symptomatic ages of 40 and 80 days. Differentially expressed genes were identified by means of the Bioconductor packages Agi4×44Preprocess and limma. FunNet web based tool was used for analysis of over-represented pathways. Furthermore, immunolabeled astrocytes from 40 and 80 days old mice were submitted to laser microdissection and RNA was extracted for evaluation of a selected gene by qPCR. Statistical analysis has pointed to 492 differentially expressed genes (155 up and 337 down regulated) in 40 days and 1105 (433 up and 672 down) in 80 days old ALS mice. KEGG analysis demonstrated the over-represented pathways tight junction, antigen processing and presentation, oxidative phosphorylation, endocytosis, chemokine signaling pathway, ubiquitin mediated proteolysis and glutamatergic synapse at both pre-symptomatic ages. Ube2i gene expression was evaluated in astrocytes from both transgenic ages, being up regulated in 40 and 80 days astrocytes enriched samples. Our data points to important early molecular events occurring in pre-symptomatic phases of ALS in mouse model. Early SUMOylation process linked to astrocytes might account to non-autonomous cell toxicity in ALS. Further studies on the signaling pathways presented here may provide new insights to better understand the events triggering motor neuron death in this devastating disorder.
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Affiliation(s)
- Gabriela P de Oliveira
- Department of Neurology, Neuroregeneration Center, University of São Paulo School of Medicine São Paulo, Brazil
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9
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Wootz H, Fitzsimons-Kantamneni E, Larhammar M, Rotterman TM, Enjin A, Patra K, André E, Van Zundert B, Kullander K, Alvarez FJ. Alterations in the motor neuron-renshaw cell circuit in the Sod1(G93A) mouse model. J Comp Neurol 2013; 521:1449-69. [PMID: 23172249 DOI: 10.1002/cne.23266] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 09/14/2012] [Accepted: 11/06/2012] [Indexed: 12/12/2022]
Abstract
Motor neurons become hyperexcitable during progression of amyotrophic lateral sclerosis (ALS). This abnormal firing behavior has been explained by changes in their membrane properties, but more recently it has been suggested that changes in premotor circuits may also contribute to this abnormal activity. The specific circuits that may be altered during development of ALS have not been investigated. Here we examined the Renshaw cell recurrent circuit that exerts inhibitory feedback control on motor neuron firing. Using two markers for Renshaw cells (calbindin and cholinergic nicotinic receptor subunit alpha2 [Chrna2]), two general markers for motor neurons (NeuN and vesicular acethylcholine transporter [VAChT]), and two markers for fast motor neurons (Chondrolectin and calcitonin-related polypeptide alpha [Calca]), we analyzed the survival and connectivity of these cells during disease progression in the Sod1(G93A) mouse model. Most calbindin-immunoreactive (IR) Renshaw cells survive to end stage but downregulate postsynaptic Chrna2 in presymptomatic animals. In motor neurons, some markers are downregulated early (NeuN, VAChT, Chondrolectin) and others at end stage (Calca). Early downregulation of presynaptic VAChT and Chrna2 was correlated with disconnection from Renshaw cells as well as major structural abnormalities of motor axon synapses inside the spinal cord. Renshaw cell synapses on motor neurons underwent more complex changes, including transitional sprouting preferentially over remaining NeuN-IR motor neurons. We conclude that the loss of presynaptic motor axon input on Renshaw cells occurs at early stages of ALS and disconnects the recurrent inhibitory circuit, presumably resulting in diminished control of motor neuron firing. J. Comp. Neurol. 521:1449-1469, 2013. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Hanna Wootz
- Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden
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Sasabe J, Aiso S. Aberrant Control of Motoneuronal Excitability in Amyotrophic Lateral Sclerosis: Excitatory Glutamate / D-Serine vs. Inhibitory Glycine/γ-Aminobutanoic Acid (GABA). Chem Biodivers 2010; 7:1479-90. [DOI: 10.1002/cbdv.200900306] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Duncan K. The role of AMPA receptor-mediated excitotoxicity in ALS: Is deficient RNA editing to blame? ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.cacc.2009.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Chang Q, Martin LJ. Glycinergic innervation of motoneurons is deficient in amyotrophic lateral sclerosis mice: a quantitative confocal analysis. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 174:574-85. [PMID: 19116365 PMCID: PMC2630565 DOI: 10.2353/ajpath.2009.080557] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/16/2008] [Indexed: 12/13/2022]
Abstract
Altered motoneuron excitability is involved in amyotrophic lateral sclerosis pathobiology. To test the hypothesis that inhibitory interneuron innervation of spinal motoneurons is abnormal in an amyotrophic lateral sclerosis mouse model, we measured GABAergic, glycinergic, and cholinergic immunoreactive terminals on spinal motoneurons in mice expressing a mutant form of human superoxide dismutase-1 with a Gly93-->Ala substitution (G93A-SOD1) and in controls at different ages. Glutamic acid decarboxylase, glycine transporter-2, and choline acetyltransferase were used as markers for GABAergic, glycinergic, and cholinergic terminals, respectively. Triple immunofluorescent labeling of boutons contacting motoneurons was visualized by confocal microscopy and analyzed quantitatively. Glycine transporter-2-bouton density on lateral motoneurons was decreased significantly in G93A-SOD1 mice compared with controls. This reduction was absent at 6 weeks of age but present in asymptomatic 8-week-old mice and worsened with disease progression from 12 to 14 weeks of age. Motoneurons lost most glycinergic innervation by 16 weeks of age (end-stage) when there was a significant decrease in the numbers of motoneurons and choline acetyltransferase-positive boutons. No significant differences in glutamic acid decarboxylase-bouton densities were found in G93A-SOD1 mice. Reduction of glycinergic innervation preceded mitochondrial swelling and vacuolization. Calbindin-positive Renshaw cell number was decreased significantly at 12 weeks of age in G93A-SOD1 mice. Thus, either the selective loss of inhibitory glycinergic regulation of motoneuron function or glycinergic interneuron degeneration contributes to motoneuron degeneration in amyotrophic lateral sclerosis.
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Affiliation(s)
- Qing Chang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Carunchio I, Mollinari C, Pieri M, Merlo D, Zona C. GAB(A) receptors present higher affinity and modified subunit composition in spinal motor neurons from a genetic model of amyotrophic lateral sclerosis. Eur J Neurosci 2009; 28:1275-85. [PMID: 18973555 DOI: 10.1111/j.1460-9568.2008.06436.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis is a neurodegenerative disease characterized by the selective degeneration of motor neurons in the spinal cord, brainstem and cerebral cortex. In this study we have analysed the electrophysiological properties of GABA(A) receptors and GABA(A) alpha1 and alpha2 subunits expression in spinal motor neurons in culture obtained from a genetic model of ALS (G93A) and compared with transgenic wild type SOD1 (SOD1) and their corresponding non transgenic litter mates (Control). Although excitotoxic motor neuron death has been extensively studied in relation to Ca(2+)-dependent processes, strong evidence indicates that excitotoxic cell death is also remarkably dependent on Cl(-) ions and on GABA(A) receptor activation. In this study we have analysed the electrophysiological properties of GABA(A) receptors and the expression of GABA(A)alpha(1) and alpha(2) subunits in cultured motor neurons obtained from a genetic model of amyotrophic lateral sclerosis (G93A) and compared them with transgenic wild-type Cu,Zn superoxide dismutase and their corresponding non-transgenic littermates (Control). In all tested motor neurons, the application of gamma-aminobutyric acid (GABA) (0.5-100 mum) evoked an inward current that was reversibly blocked by bicuculline (100 mum), thus indicating that it was mediated by the activation of GABA(A) receptors. Our results indicate that the current density at high GABA concentrations is similar in control, Cu,Zn superoxide dismutase and G93A motor neurons. However, the dose-response curve significantly shifted toward lower concentration values in G93A motor neurons and the extent of desensitization also increased in these neurons. Finally, multiplex single-cell real-time polymerase chain reaction and immunofluorescence revealed that the amount of GABA(A)alpha(1) subunit was significantly increased in G93A motor neurons, whereas the levels of alpha(2) subunit were unchanged. These data show that the functionality and expression of GABA(A) receptors are altered in G93A motor neurons inducing a higher Cl(-) influx into the cell with a possible consequent neuronal excitotoxicity acceleration.
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Affiliation(s)
- Irene Carunchio
- Department of Neuroscience, University of Rome 'Tor Vergata', Via Montpellier 1, 00173 Rome, Italy
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Minciacchi D, Kassa RM, Del Tongo C, Mariotti R, Bentivoglio M. Voronoi-based spatial analysis reveals selective interneuron changes in the cortex of FALS mice. Exp Neurol 2009; 215:77-86. [DOI: 10.1016/j.expneurol.2008.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 09/01/2008] [Accepted: 09/15/2008] [Indexed: 12/13/2022]
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Niessen HG, Debska-Vielhaber G, Sander K, Angenstein F, Ludolph AC, Hilfert L, Willker W, Leibfritz D, Heinze HJ, Kunz WS, Vielhaber S. Metabolic progression markers of neurodegeneration in the transgenic G93A-SOD1 mouse model of amyotrophic lateral sclerosis. Eur J Neurosci 2007; 25:1669-77. [PMID: 17432958 DOI: 10.1111/j.1460-9568.2007.05415.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by a progressive loss of motor neurons. Visualizing corresponding metabolic changes in the brain of patients with ALS with proton magnetic resonance spectroscopy ((1)H-MRS) may provide surrogate markers for an early disease detection, for monitoring the progression and for evaluating a treatment response. The primary objective of our study was to evaluate whether modifications in MR metabolite levels occur before clinical disease onset, and whether these changes are directly linked to a distinct spatial progression pattern in the CNS. Therefore, age-dependent alterations in the cerebral and spinal metabolic profile in the mouse model of ALS overexpressing the mutated human G93A-superoxide dismutase 1 (G93A-SOD1) were determined by high-resolution MRS of tissue extracts at 14.1 Tesla. Both non-transgenic mice (control mice) and transgenic mice overexpressing the non-mutated human SOD1 (tg-SOD1) served as controls. In the spinal cord of G93A-SOD1 mice significantly decreased levels of N-acetyl aspartate were already detected 34 days postpartum, i.e. about 60 days before the average disease onset caused by motor neuron decline. In addition, glutamine and gamma-aminobutyric acid concentrations were significantly diminished at Day 75, which is still in the presymptomatic phase of the disease. These metabolic changes were further progressive in the course of the disease and started to involve the brainstem at Day 75. Overall, high-resolution (1)H-MRS allows a sensitive spatial and temporal metabolite profiling in the presymptomatic phase of ALS even before significant neuronal cell loss occurs.
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Affiliation(s)
- Heiko G Niessen
- Department of Neurology II, Otto-von-Guericke University Magdeburg, Leipziger Str 44, Magdeburg, Germany
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Lorenzo LE, Barbe A, Portalier P, Fritschy JM, Bras H. Differential expression of GABAA and glycine receptors in ALS-resistant vs. ALS-vulnerable motoneurons: possible implications for selective vulnerability of motoneurons. Eur J Neurosci 2007; 23:3161-70. [PMID: 16820006 DOI: 10.1111/j.1460-9568.2006.04863.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Summary Amyotrophic lateral sclerosis (ALS) is a devastating motoneuronal degenerative disease, which is inevitably fatal in adults. ALS is characterized by an extensive loss of motoneurons in the cerebrospinal axis, except for those motoneurons that control eye movements and bladder contraction. The reason for this selectivity is not known. Systematic differences have been found in the organization of excitatory synaptic transmission in ALS-resistant vs. ALS-susceptible motor nuclei. However, although motoneurons express high levels of glycine receptors (GlyR) and GABA(A) receptors (GABA(A)R), no such studies have been carried out yet for inhibitory synaptic transmission. In this study, we compared the subunit composition, patterns of expression, density and synaptic localization of inhibitory synaptic receptors in ALS-resistant (oculomotor, trochlear and abducens) and ALS-vulnerable motoneurons (trigeminal, facial and hypoglossi). Triple immunofluorescent stainings of the major GABA(A)R subunits (alpha1, alpha2, alpha3, and alpha5), the GlyR alpha1 subunit and gephyrin, were visualized by confocal microscopy and analysed quantitatively. A strong correlation was observed between the vulnerability of motoneurons and the subunit composition of GABA(A)R, the GlyR/GABA(A)R density ratios and the incidence of synaptic vs. extrasynaptic GABA(A)R. These differences contrast strikingly with the uniform gephyrin cluster density and synaptic GlyR levels recorded in all motor nuclei examined. These results suggest that the specific patterns of inhibitory receptor organization observed might reflect functional differences that are relevant to the physiopathology of ALS.
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