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Odierna GL, Vucic S, Dyer M, Dickson T, Woodhouse A, Blizzard C. How do we get from hyperexcitability to excitotoxicity in amyotrophic lateral sclerosis? Brain 2024; 147:1610-1621. [PMID: 38408864 PMCID: PMC11068114 DOI: 10.1093/brain/awae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/15/2023] [Accepted: 12/10/2023] [Indexed: 02/28/2024] Open
Abstract
Amyotrophic lateral sclerosis is a devastating neurodegenerative disease that, at present, has no effective cure. Evidence of increased circulating glutamate and hyperexcitability of the motor cortex in patients with amyotrophic lateral sclerosis have provided an empirical support base for the 'dying forward' excitotoxicity hypothesis. The hypothesis postulates that increased activation of upper motor neurons spreads pathology to lower motor neurons in the spinal cord in the form of excessive glutamate release, which triggers excitotoxic processes. Many clinical trials have focused on therapies that target excitotoxicity via dampening neuronal activation, but not all are effective. As such, there is a growing tension between the rising tide of evidence for the 'dying forward' excitotoxicity hypothesis and the failure of therapies that target neuronal activation. One possible solution to these contradictory outcomes is that our interpretation of the current evidence requires revision in the context of appreciating the complexity of the nervous system and the limitations of the neurobiological assays we use to study it. In this review we provide an evaluation of evidence relevant to the 'dying forward' excitotoxicity hypothesis and by doing so, identify key gaps in our knowledge that need to be addressed. We hope to provide a road map from hyperexcitability to excitotoxicity so that we can better develop therapies for patients suffering from amyotrophic lateral sclerosis. We conclude that studies of upper motor neuron activity and their synaptic output will play a decisive role in the future of amyotrophic lateral sclerosis therapy.
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Affiliation(s)
- G Lorenzo Odierna
- Tasmanian School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - Steve Vucic
- Brain and Nerve Research Center, The University of Sydney, Sydney 2050, Australia
| | - Marcus Dyer
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
- Department of Pharmaceutical and Pharmacological Sciences, Center for Neurosciences, Vrije Universiteit Brussel (VUB), 1090 Brussels, Belgium
| | - Tracey Dickson
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
| | - Adele Woodhouse
- The Wicking Dementia Centre, University of Tasmania, Hobart, TAS 7000, Australia
| | - Catherine Blizzard
- Tasmanian School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
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2
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Lépine S, Castellanos-Montiel MJ, Durcan TM. TDP-43 dysregulation and neuromuscular junction disruption in amyotrophic lateral sclerosis. Transl Neurodegener 2022; 11:56. [PMID: 36575535 PMCID: PMC9793560 DOI: 10.1186/s40035-022-00331-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/29/2022] [Indexed: 12/28/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease characterized by upper and lower motor neuron (MN) loss with a signature feature of cytoplasmic aggregates containing TDP-43, which are detected in nearly all patients. Mutations in the gene that encodes TDP-43 (TARBDP) are known to result in both familial and sporadic ALS. In ALS, disruption of neuromuscular junctions (NMJs) constitutes a critical event in disease pathogenesis, leading to denervation atrophy, motor impairments and disability. Morphological defects and impaired synaptic transmission at NMJs have been reported in several TDP-43 animal models and in vitro, linking TDP-43 dysregulation to the loss of NMJ integrity in ALS. Through the lens of the dying-back and dying-forward hypotheses of ALS, this review discusses the roles of TDP-43 related to synaptic function, with a focus on the potential molecular mechanisms occurring within MNs, skeletal muscles and glial cells that may contribute to NMJ disruption in ALS.
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Affiliation(s)
- Sarah Lépine
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada ,grid.14709.3b0000 0004 1936 8649Faculty of Medicine and Health Sciences, McGill University, 3605 De La Montagne, Montreal, QC H3G 2M1 Canada
| | - Maria José Castellanos-Montiel
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
| | - Thomas Martin Durcan
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
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3
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Ding Q, Kesavan K, Lee KM, Wimberger E, Robertson T, Gill M, Power D, Chang J, Fard AT, Mar JC, Henderson RD, Heggie S, McCombe PA, Jeffree RL, Colditz MJ, Hilliard MA, Ng DCH, Steyn FJ, Phillips WD, Wolvetang EJ, Ngo ST, Noakes PG. Impaired signaling for neuromuscular synaptic maintenance is a feature of Motor Neuron Disease. Acta Neuropathol Commun 2022; 10:61. [PMID: 35468848 PMCID: PMC9040261 DOI: 10.1186/s40478-022-01360-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 11/17/2022] Open
Abstract
A central event in the pathogenesis of motor neuron disease (MND) is the loss of neuromuscular junctions (NMJs), yet the mechanisms that lead to this event in MND remain to be fully elucidated. Maintenance of the NMJ relies upon neural agrin (n-agrin) which, when released from the nerve terminal, activates the postsynaptic Muscle Specific Kinase (MuSK) signaling complex to stabilize clusters of acetylcholine receptors. Here, we report that muscle from MND patients has an increased proportion of slow fibers and muscle fibers with smaller diameter. Muscle cells cultured from MND biopsies failed to form large clusters of acetylcholine receptors in response to either non-MND human motor axons or n-agrin. Furthermore, levels of expression of MuSK, and MuSK-complex components: LRP4, Caveolin-3, and Dok7 differed between muscle cells cultured from MND patients compared to those from non-MND controls. To our knowledge, this is the first time a fault in the n-agrin-LRP4-MuSK signaling pathway has been identified in muscle from MND patients. Our results highlight the n-agrin-LRP4-MuSK signaling pathway as a potential therapeutic target to prolong muscle function in MND.
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4
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Alteration of the Neuromuscular Junction and Modifications of Muscle Metabolism in Response to Neuron-Restricted Expression of the CHMP2Bintron5 Mutant in a Mouse Model of ALS-FTD Syndrome. Biomolecules 2022; 12:biom12040497. [PMID: 35454086 PMCID: PMC9025139 DOI: 10.3390/biom12040497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/12/2022] [Accepted: 03/21/2022] [Indexed: 02/04/2023] Open
Abstract
CHMP2B is a protein that coordinates membrane scission events as a core component of the ESCRT machinery. Mutations in CHMP2B are an uncommon cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two neurodegenerative diseases with clinical, genetic, and pathological overlap. Different mutations have now been identified across the ALS-FTD spectrum. Disruption of the neuromuscular junction is an early pathogenic event in ALS. Currently, the links between neuromuscular junction functionality and ALS-associated genes, such as CHMP2B, remain poorly understood. We have previously shown that CHMP2B transgenic mice expressing the CHMP2Bintron5 mutant specifically in neurons develop a progressive motor phenotype reminiscent of ALS. In this study, we used complementary approaches (behavior, histology, electroneuromyography, and biochemistry) to determine the extent to which neuron-specific expression of CHMP2Bintron5 could impact the skeletal muscle characteristics. We show that neuronal expression of the CHMP2Bintron5 mutant is sufficient to trigger progressive gait impairment associated with structural and functional changes in the neuromuscular junction. Indeed, CHMP2Bintron5 alters the pre-synaptic terminal organization and the synaptic transmission that ultimately lead to a switch of fast-twitch glycolytic muscle fibers to more oxidative slow-twitch muscle fibers. Taken together these data indicate that neuronal expression of CHMP2Bintron5 is sufficient to induce a synaptopathy with molecular and functional changes in the motor unit reminiscent of those found in ALS patients.
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5
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Verma S, Khurana S, Vats A, Sahu B, Ganguly NK, Chakraborti P, Gourie-Devi M, Taneja V. Neuromuscular Junction Dysfunction in Amyotrophic Lateral Sclerosis. Mol Neurobiol 2022; 59:1502-1527. [PMID: 34997540 DOI: 10.1007/s12035-021-02658-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by progressive degeneration of motor neurons leading to skeletal muscle denervation. Earlier studies have shown that motor neuron degeneration begins in motor cortex and descends to the neuromuscular junction (NMJ) in a dying forward fashion. However, accumulating evidences support that ALS is a distal axonopathy where early pathological changes occur at the NMJ, prior to onset of clinical symptoms and propagates towards the motor neuron cell body supporting "dying back" hypothesis. Despite several evidences, series of events triggering NMJ disassembly in ALS are still obscure. Neuromuscular junction is a specialized tripartite chemical synapse which involves a well-coordinated communication among the presynaptic motor neuron, postsynaptic skeletal muscle, and terminal Schwann cells. This review provides comprehensive insight into the role of NMJ in ALS pathogenesis. We have emphasized the molecular alterations in cellular components of NMJ leading to loss of effective neuromuscular transmission in ALS. Further, we provide a preview into research involved in exploring NMJ as potential target for designing effective therapies for ALS.
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Affiliation(s)
- Sagar Verma
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.,Department of Biotechnology, Jamia Hamdard, Delhi, India
| | - Shiffali Khurana
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.,Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, Delhi, India
| | - Abhishek Vats
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bandana Sahu
- Department of Research, Sir Ganga Ram Hospital, Delhi, India
| | | | | | | | - Vibha Taneja
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.
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6
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Pasniceanu IS, Atwal MS, Souza CDS, Ferraiuolo L, Livesey MR. Emerging Mechanisms Underpinning Neurophysiological Impairments in C9ORF72 Repeat Expansion-Mediated Amyotrophic Lateral Sclerosis/Frontotemporal Dementia. Front Cell Neurosci 2022; 15:784833. [PMID: 34975412 PMCID: PMC8715728 DOI: 10.3389/fncel.2021.784833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are characterized by degeneration of upper and lower motor neurons and neurons of the prefrontal cortex. The emergence of the C9ORF72 hexanucleotide repeat expansion mutation as the leading genetic cause of ALS and FTD has led to a progressive understanding of the multiple cellular pathways leading to neuronal degeneration. Disturbances in neuronal function represent a major subset of these mechanisms and because such functional perturbations precede degeneration, it is likely that impaired neuronal function in ALS/FTD plays an active role in pathogenesis. This is supported by the fact that ALS/FTD patients consistently present with neurophysiological impairments prior to any apparent degeneration. In this review we summarize how the discovery of the C9ORF72 repeat expansion mutation has contributed to the current understanding of neuronal dysfunction in ALS/FTD. Here, we discuss the impact of the repeat expansion on neuronal function in relation to intrinsic excitability, synaptic, network and ion channel properties, highlighting evidence of conserved and divergent pathophysiological impacts between cortical and motor neurons and the influence of non-neuronal cells. We further highlight the emerging association between these dysfunctional properties with molecular mechanisms of the C9ORF72 mutation that appear to include roles for both, haploinsufficiency of the C9ORF72 protein and aberrantly generated dipeptide repeat protein species. Finally, we suggest that relating key pathological observations in C9ORF72 repeat expansion ALS/FTD patients to the mechanistic impact of the C9ORF72 repeat expansion on neuronal function will lead to an improved understanding of how neurophysiological dysfunction impacts upon pathogenesis.
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Affiliation(s)
- Iris-Stefania Pasniceanu
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Manpreet Singh Atwal
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Cleide Dos Santos Souza
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Laura Ferraiuolo
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Matthew R Livesey
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
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7
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Gromova A, La Spada AR. Harmony Lost: Cell-Cell Communication at the Neuromuscular Junction in Motor Neuron Disease. Trends Neurosci 2021; 43:709-724. [PMID: 32846148 DOI: 10.1016/j.tins.2020.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/05/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022]
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that is the point of connection between motor neurons and skeletal muscle. Although developmental studies have established the importance of cell-cell communication at the NMJ for the integrity and full functionality of this synapse, the contribution of this structure as a primary driver in motor neuron disease pathogenesis remains uncertain. Here, we consider the biology of the NMJ and review emerging lines of investigation that are highlighting the importance of cell-cell interaction at the NMJ in spinal muscular atrophy (SMA), X-linked spinal and bulbar muscular atrophy (SBMA), and amyotrophic lateral sclerosis (ALS). Ongoing research may reveal NMJ targets and pathways whose therapeutic modulation will help slow the progression of motor neuron disease, offering a novel treatment paradigm for ALS, SBMA, SMA, and related disorders.
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Affiliation(s)
- Anastasia Gromova
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093, USA; Department of Pathology and Laboratory Medicine and Department of Neurology, University of California Irvine, Irvine, CA 92697, USA
| | - Albert R La Spada
- Department of Pathology and Laboratory Medicine and Department of Neurology, University of California Irvine, Irvine, CA 92697, USA; Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA.
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8
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D’Amico E, Grosso G, Nieves JW, Zanghì A, Factor-Litvak P, Mitsumoto H. Metabolic Abnormalities, Dietary Risk Factors and Nutritional Management in Amyotrophic Lateral Sclerosis. Nutrients 2021; 13:nu13072273. [PMID: 34209133 PMCID: PMC8308334 DOI: 10.3390/nu13072273] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a devastating progressive neurodegenerative disease that affects motor neurons, leading to a relentless paralysis of skeletal muscles and eventual respiratory failure. Although a small percentage of patients may have a longer survival time (up to 10 years), in most cases, the median survival time is from 20 to 48 months. The pathogenesis and risk factors for ALS are still unclear: among the various aspects taken into consideration, metabolic abnormalities and nutritional factors have been the focus of recent interests. Although there are no consistent findings regarding prior type-2 diabetes, hypercholesterolemia and ALS incidence, abnormalities in lipid and glucose metabolism may be linked to disease progression, leading to a relatively longer survival (probably as a result of counteract malnutrition and cachexia in the advanced stages of the disease). Among potential dietary risk factors, a higher risk of ALS has been associated with an increased intake of glutamate, while the consumption of antioxidant and anti-inflammatory compounds, such as vitamin E, n-3 polyunsaturated fatty acids, and carotenoids, has been related to lower incidence. Poor nutritional status and weight loss in ALS resulting from poor oral intake, progressive muscle atrophy, and the potential hypermetabolic state have been associated with rapid disease progression. It seems important to routinely perform a nutritional assessment of ALS patients at the earliest referral: weight maintenance (if adequate) or gain (if underweight) is suggested from the scientific literature; evidence of improved diet quality (in terms of nutrients and limits for pro-inflammatory dietary factors) and glucose and lipid control is yet to be confirmed, but it is advised. Further research is warranted to better understand the role of nutrition and the underlying metabolic abnormalities in ALS, and their contribution to the pathogenic mechanisms leading to ALS initiation and progression.
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Affiliation(s)
- Emanuele D’Amico
- Department G.F. Ingrassia, University of Catania, 95123 Catania, Italy; (E.D.); (A.Z.)
| | - Giuseppe Grosso
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Correspondence: ; Tel.: +39-0954-781-187
| | - Jeri W. Nieves
- Mailman School of Public Health and Institute of Human Nutrition, Columbia University, New York, NY 10032, USA; (J.W.N.); (P.F.-L.)
| | - Aurora Zanghì
- Department G.F. Ingrassia, University of Catania, 95123 Catania, Italy; (E.D.); (A.Z.)
| | - Pam Factor-Litvak
- Mailman School of Public Health and Institute of Human Nutrition, Columbia University, New York, NY 10032, USA; (J.W.N.); (P.F.-L.)
| | - Hiroshi Mitsumoto
- Eleanor and Lou Gehrig ALS Center, The Neurological Institute of New York Columbia University Medical Center, New York, NY 10032, USA;
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9
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Butti Z, Pan YE, Giacomotto J, Patten SA. Reduced C9orf72 function leads to defective synaptic vesicle release and neuromuscular dysfunction in zebrafish. Commun Biol 2021; 4:792. [PMID: 34172817 PMCID: PMC8233344 DOI: 10.1038/s42003-021-02302-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 06/03/2021] [Indexed: 11/16/2022] Open
Abstract
The most common genetic cause of amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia (FTD) is a hexanucleotide repeat expansion within the C9orf72 gene. Reduced levels of C9orf72 mRNA and protein have been found in ALS/FTD patients, but the role of this protein in disease pathogenesis is still poorly understood. Here, we report the generation and characterization of a stable C9orf72 loss-of-function (LOF) model in the zebrafish. We show that reduced C9orf72 function leads to motor defects, muscle atrophy, motor neuron loss and mortality in early larval and adult stages. Analysis of the structure and function of the neuromuscular junctions (NMJs) of the larvae, reveal a marked reduction in the number of presynaptic and postsynaptic structures and an impaired release of quantal synaptic vesicles at the NMJ. Strikingly, we demonstrate a downregulation of SV2a upon C9orf72-LOF and a reduced rate of synaptic vesicle cycling. Furthermore, we show a reduced number and size of Rab3a-postive synaptic puncta at NMJs. Altogether, these results reveal a key function for C9orf72 in the control of presynaptic vesicle trafficking and release at the zebrafish larval NMJ. Our study demonstrates an important role for C9orf72 in ALS/FTD pathogenesis, where it regulates synaptic vesicle release and neuromuscular functions. Butti et al. generate a C9orf72 loss-of-function model in zebrafish. They find that that C9orf72 is required for presynaptic vesicle trafficking and release at the zebrafish larval neuromuscular junctions. This study provides functional insights into the pathogenesis of amyotrophic lateral sclerosis and fronto-temporal dementia.
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Affiliation(s)
- Zoé Butti
- INRS- Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
| | | | - Jean Giacomotto
- Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia.,Queensland Centre for Mental Health Research, Brisbane, QLD, Australia
| | - Shunmoogum A Patten
- INRS- Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada. .,Centre d'Excellence en Recherche sur les Maladies Orphelines - Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montréal, QC, Canada.
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10
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Maselli RA, Wei DT, Hodgson TS, Sampson JB, Vazquez J, Smith HL, Pytel P, Ferns M. Dominant and recessive congenital myasthenic syndromes caused by SYT2 mutations. Muscle Nerve 2021; 64:219-224. [PMID: 34037996 DOI: 10.1002/mus.27332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/14/2021] [Accepted: 05/19/2021] [Indexed: 01/11/2023]
Abstract
INTRODUCTION/AIMS We studied a patient with a congenital myasthenic syndrome (CMS) caused by a dominant mutation in the synaptotagmin 2 gene (SYT2) and compared the clinical features of this patient with those of a previously described patient with a recessive mutation in the same gene. METHODS We performed electrodiagnostic (EDX) studies, genetic studies, muscle biopsy, microelectrode recordings and electron microscopy (EM). RESULTS Both patients presented with muscle weakness and bulbar deficits, which were worse in the recessive form. EDX studies showed presynaptic failure, which was more prominent in the recessive form. Microelectrode studies in the dominant form showed a marked reduction of the quantal content, which increased linearly with higher frequencies of nerve stimulation. The MEPP frequencies were normal at rest but increased markedly with higher frequencies of nerve stimulation. The EM demonstrated overdeveloped postsynaptic folding, and abundant endosomes, multivesicular bodies and degenerative lamellar bodies inside small nerve terminals. DISCUSSION The recessive form of CMS caused by a SYT2 mutation showed far more severe clinical manifestations than the dominant form. The pathogenesis of the dominant form likely involves a dominant-negative effect due to disruption of the dual function of synaptotagmin as a Ca2+ -sensor and modulator of synaptic vesicle exocytosis.
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Affiliation(s)
- Ricardo A Maselli
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - David T Wei
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - Trent S Hodgson
- Kaiser Permanente Oakland Medical Center, Oakland, California, USA
| | - Jacinda B Sampson
- Department of Neurology, Stanford University, Palo Alto, California, USA
| | - Jessica Vazquez
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - Heather L Smith
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Peter Pytel
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Michael Ferns
- Department of Anesthesiology, University of California Davis, Davis, California, USA
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11
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Alhindi A, Boehm I, Chaytow H. Small junction, big problems: Neuromuscular junction pathology in mouse models of amyotrophic lateral sclerosis (ALS). J Anat 2021; 241:1089-1107. [PMID: 34101196 PMCID: PMC9558162 DOI: 10.1111/joa.13463] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 01/31/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a motor neuron disease with an extremely heterogeneous clinical and genetic phenotype. In our efforts to find therapies for ALS, the scientific community has developed a plethora of mouse models, each with their own benefits and drawbacks. The peripheral nervous system, specifically the neuromuscular junction (NMJ), is known to be affected in ALS patients and shows marked dysfunction across mouse models. Evidence of pathology at the NMJ includes denervated NMJs, changes in endplate size and loss of terminal Schwann cells. This review compares the temporal disease progression with severity of disease at the NMJ in mouse models with the most commonly mutated genes in ALS patients (SOD1, C9ORF72, TARDBP and FUS). Despite variability, early NMJ dysfunction seems to be a common factor in models with SOD1, TARDBP and FUS mutations, while C9ORF72 models do not appear to follow the same pattern of pathology. Further work into determining the timing of NMJ pathology, particularly in newer ALS mouse models, will confirm its pivotal role in ALS pathogenesis and therefore highlight the NMJ as a potential therapeutic target.
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Affiliation(s)
- Abrar Alhindi
- Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Department of Anatomy, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Ines Boehm
- Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Helena Chaytow
- Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
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12
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Zebrafish, an In Vivo Platform to Screen Drugs and Proteins for Biomedical Use. Pharmaceuticals (Basel) 2021; 14:ph14060500. [PMID: 34073947 PMCID: PMC8225009 DOI: 10.3390/ph14060500] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 12/28/2022] Open
Abstract
The nearly simultaneous convergence of human genetics and advanced molecular technologies has led to an improved understanding of human diseases. At the same time, the demand for drug screening and gene function identification has also increased, albeit time- and labor-intensive. However, bridging the gap between in vitro evidence from cell lines and in vivo evidence, the lower vertebrate zebrafish possesses many advantages over higher vertebrates, such as low maintenance, high fecundity, light-induced spawning, transparent embryos, short generation interval, rapid embryonic development, fully sequenced genome, and some phenotypes similar to human diseases. Such merits have popularized the zebrafish as a model system for biomedical and pharmaceutical studies, including drug screening. Here, we reviewed the various ways in which zebrafish serve as an in vivo platform to perform drug and protein screening in the fields of rare human diseases, social behavior and cancer studies. Since zebrafish mutations faithfully phenocopy many human disorders, many compounds identified from zebrafish screening systems have advanced to early clinical trials, such as those for Adenoid cystic carcinoma, Dravet syndrome and Diamond-Blackfan anemia. We also reviewed and described how zebrafish are used to carry out environmental pollutant detection and assessment of nanoparticle biosafety and QT prolongation.
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13
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Dissanayake KN, Chou RCC, Thompson A, Margetiny F, Davie C, McKinnon S, Patel V, Sultatos L, McArdle JJ, Clutton RE, Eddleston M, Ribchester RR. Impaired neuromuscular function by conjoint actions of organophosphorus insecticide metabolites omethoate and cyclohexanol with implications for treatment of respiratory failure. Clin Toxicol (Phila) 2021; 59:1239-1258. [PMID: 33988053 DOI: 10.1080/15563650.2021.1916519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Ingestion of agricultural organophosphorus insecticides is a significant cause of death in rural Asia. Patients often show acute respiratory failure and/or delayed, unexplained signs of neuromuscular paralysis, sometimes diagnosed as "Intermediate Syndrome". We tested the hypothesis that omethoate and cyclohexanol, circulating metabolites of one agricultural formulation, cause muscle weakness and paralysis. METHODS Acetylcholinesterase activity of insecticide components and metabolites was measured using purified enzyme from eel electroplaque or muscle homogenates. Mechanomyographic recording of pelvic limb responses to nerve stimulation was made in anaesthetized pigs and isometric force was recorded from isolated nerve-muscle preparations from mice. Omethoate and cyclohexanol were administered intravenously or added to physiological saline bathing isolated muscle. We also assessed the effect of MgSO4 and cooling on neuromuscular function. RESULTS Omethoate caused tetanic fade in pig muscles and long-lasting contractions of the motor innervation zone in mouse muscle. Both effects were mitigated, either by i.v. administration of MgSO4 in vivo or by adding 5 mM Mg2+ to the medium bathing isolated preparations. Combination of omethoate and cyclohexanol initially potentiated muscle contractions but then rapidly blocked them. Cyclohexanol alone caused fade and block of muscle contractions in pigs and in isolated preparations. Similar effects were observed ex vivo with cyclohexanone and xylene. Cyclohexanol-induced neuromuscular block was temperature-sensitive and rapidly reversible. CONCLUSIONS The data indicate a crucial role for organophosphorus and solvent metabolites in muscle weakness following ingestion of agricultural OP insecticide formulations. The metabolites omethoate and cyclohexanol acted conjointly to impair neuromuscular function but their effects were mitigated by elevating extracellular Mg2+ and decreasing core temperature, respectively. Clinical studies of MgSO4 therapy and targeted temperature management in insecticide-poisoned patients are required to determine whether they may be effective adjuncts to treatment.
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Affiliation(s)
- Kosala N Dissanayake
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Pharmacology, Toxicology and Therapeutics, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | | | - Adrian Thompson
- Pharmacology, Toxicology and Therapeutics, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Filip Margetiny
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Charlotte Davie
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Scott McKinnon
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Vishwendra Patel
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Lester Sultatos
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Joseph J McArdle
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Richard E Clutton
- Wellcome Trust Critical Care Laboratory for Large Animals, Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - Michael Eddleston
- Pharmacology, Toxicology and Therapeutics, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
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TDP-43 Regulation of AChE Expression Can Mediate ALS-Like Phenotype in Zebrafish. Cells 2021; 10:cells10020221. [PMID: 33499374 PMCID: PMC7911940 DOI: 10.3390/cells10020221] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 12/12/2022] Open
Abstract
The "distal axonopathy" hypothesis in amyotrophic lateral sclerosis (ALS) proposes that pathological changes occur at the neuromuscular junction (NMJ) early in the disease. While acetylcholinesterase (AChE) plays an important role in the functionality of the NMJ, its potential role in ALS remains unexplored. Here, we identified AChE as a limiting factor regulating muscle/motor neuron connection in a vertebrate model of ALS. Knockdown of the TAR DNA-binding protein 43 (TDP-43) orthologue in zebrafish resulted in early defects of motor functions coupled with NMJ disassembly. We found that a partially depleted tdp-43 caused a decrease of ache expression. Importantly, human AChE overexpression reduced the phenotypic defects in the tdp-43 loss of function model, with amelioration of post- and pre-synaptic deficits at the NMJ. In conclusion, our results provide a better understanding of the role of TDP-43 in the NMJ organization and indicate AChE as a contributing factor in the pathology of ALS. In particular, it may be implicated in the early defects that characterize NMJs in this major neurodegenerative disorder.
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15
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Besser RR, Bowles AC, Alassaf A, Carbonero D, Maciel R, Saporta M, Agarwal A. A Chemically Defined Common Medium for Culture of C2C12 Skeletal Muscle and Human Induced Pluripotent Stem Cell Derived Spinal Spheroids. Cell Mol Bioeng 2020; 13:605-619. [PMID: 33281990 PMCID: PMC7704992 DOI: 10.1007/s12195-020-00624-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/03/2020] [Indexed: 01/14/2023] Open
Abstract
INTRODUCTION Multicellular platforms and linked multi organ on chip devices are powerful tools for drug discovery, and basic mechanistic studies. Often, a critical constraint is defining a culture medium optimal for all cells present in the system. In this study, we focused on the key cells of the neuromuscular junction i.e., skeletal muscle and motor neurons. METHODS Formulation of a chemically defined medium for the co-culture of C2C12 skeletal muscle cells and human induced pluripotent stem cell (hiPSC) derived spinal spheroids (SpS) was optimized. C2C12 cells in 10 experimental media conditions and 2 topographies were evaluated over a 14-day maturation period to determine the ideal medium formulation for skeletal muscle tissue development. RESULTS During early maturation, overexpression of genes for myogenesis and myopathy was observed for several media conditions, corresponding to muscle delamination and death. Together, we identified 3 media formulations that allowed for more controlled differentiation, healthier muscle tissue, and long-term culture duration. This evidence was then used to select media formulations to culture SpS and subsequently assessed axonal growth. As axonal growth in SpS cultures was comparable in all selected media conditions, our data suggest that the neuronal basal medium with no added supplements is the ideal medium formulation for both cell types. CONCLUSIONS Optimization using both topographical cues and culture media formulations provides a comprehensive analyses of culture conditions that are vital to future applications for in vitro NMJ models.
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Affiliation(s)
- Rachel R. Besser
- Department of Biomedical Engineering, DJTMF Biomedical Nanotechnology Institute, University of Miami, 1251 Memorial Dr, MEA 203, Coral Gables, FL 33146 USA
| | - Annie C. Bowles
- Department of Biomedical Engineering, DJTMF Biomedical Nanotechnology Institute, University of Miami, 1251 Memorial Dr, MEA 203, Coral Gables, FL 33146 USA
| | - Ahmad Alassaf
- Department of Biomedical Engineering, DJTMF Biomedical Nanotechnology Institute, University of Miami, 1251 Memorial Dr, MEA 203, Coral Gables, FL 33146 USA
- Department of Medical Equipment Technology, College of Applied Medical Sciences, Majmaah University, Al-Majmaah, 11952 Saudi Arabia
| | - Daniel Carbonero
- Department of Biomedical Engineering, DJTMF Biomedical Nanotechnology Institute, University of Miami, 1251 Memorial Dr, MEA 203, Coral Gables, FL 33146 USA
| | - Renata Maciel
- Department of Neurology, University of Miami Miller School of Medicine, 1120 NW 14th St, Suite 1310, Miami, FL 33136 USA
| | - Mario Saporta
- Department of Neurology, University of Miami Miller School of Medicine, 1120 NW 14th St, Suite 1310, Miami, FL 33136 USA
| | - Ashutosh Agarwal
- Department of Biomedical Engineering, DJTMF Biomedical Nanotechnology Institute, University of Miami, 1251 Memorial Dr, MEA 203, Coral Gables, FL 33146 USA
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Zhang Z, Guan Y, Han J, Li M, Shi M, Deng H. Regional Features of MuSK Antibody-Positive Myasthenia Gravis in Northeast China. Front Neurol 2020; 11:516211. [PMID: 33123066 PMCID: PMC7566902 DOI: 10.3389/fneur.2020.516211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 08/21/2020] [Indexed: 11/17/2022] Open
Abstract
Objective: To summarize the characteristics of muscle-specific receptor tyrosine kinase antibody-positive myasthenia gravis (MuSK-MG) in Northeast China. Methods: We retrospectively collected 183 confirmed MG patients and divided them into three groups based on the type of serum antibodies: MuSK-MG (14 cases), acetylcholine receptor (AChR)-MG (130 cases), and double-seronegative (DSN)-MG (39 cases). The clinical, diagnostic, therapeutic, and prognosis data were analyzed. Results: MuSK antibody was detected in 26.7% of seronegative MG. The mean age of onset in MuSK-MG was 53.2 ± 13.6 years. Fifty percent of MuSK-MG patients with an onset symptom of pure ocular muscle weakness. The time from onset to other muscle groups' involvement and the time from onset to myasthenic crisis had no significant difference among the three groups (P > 0.05). The proportion of Osserman classification I in MuSK-MG group was lower than that in DSN-MG group. The proportion of Osserman classification IV in MuSK-MG group was higher than that in the other two groups. The incidences of other coexisting autoimmune diseases in MuSK-MG group were higher. Prognosis after the treatment of steroid combined with tacrolimus for MuSK-MG was similar to AChR-MG treated with steroid combined with an immunosuppressant agent (P > 0.05). Conclusion: Patients with MuSK-MG in Northeast China have a modestly later onset age and a proportion of patients may have a mild form of the disease with delayed disease progression. We confirmed the existence of a rare ocular MuSK-MG phenotype, a high proportion of coexisting with other autoimmune diseases, and a good response to steroids combined with tacrolimus for our MuSK-MG series.
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Affiliation(s)
- Zunwei Zhang
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Yujia Guan
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Jiale Han
- Department of Endocrinology, First Hospital of Jilin University, Changchun, China
| | - Mingming Li
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Miao Shi
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
| | - Hui Deng
- Department of Neurology and Neuroscience Center, First Hospital of Jilin University, Changchun, China
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Bose P, Tremblay E, Maios C, Narasimhan V, Armstrong GAB, Liao M, Parker JA, Robitaille R, Wen XY, Barden C, Drapeau P. The Novel Small Molecule TRVA242 Stabilizes Neuromuscular Junction Defects in Multiple Animal Models of Amyotrophic Lateral Sclerosis. Neurotherapeutics 2019; 16:1149-1166. [PMID: 31342410 PMCID: PMC6985319 DOI: 10.1007/s13311-019-00765-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a debilitating neurodegenerative disorder in which the neuromuscular junction progressively degenerates, leading to movement difficulties, paralysis, and eventually death. ALS is currently being treated by only two FDA-approved drugs with modest efficacy in slowing disease progression. Often, the translation of preclinical findings to bedside terminates prematurely as the evaluation of potential therapeutic compounds focuses on a single study or a single animal model. To circumscribe these issues, we screened 3,765 novel small molecule derivatives of pimozide, a recently identified repurposed neuroleptic for ALS, in Caenorhabditis elegans, confirmed the hits in zebrafish and validated the most active compounds in mouse genetic models. Out of the 27 small molecules identified from the high-throughput screen in worms, 4 were found to recover locomotor defects in C. elegans and genetic zebrafish models of ALS. TRVA242 was identified as the most potent compound as it significantly improved efficiency in rescuing locomotor, motorneuron, and neuromuscular junction synaptic deficits in a C. elegans TDP-43 model and in multiple zebrafish genetic (TDP-43, SOD1, and C9ORF72) models of ALS. The actions of TRVA242 were also conserved in a mammalian model as it also stabilized neuromuscular junction deficits in a mouse SOD1 model of ALS. Compounds such as TRVA242 therefore represent new potential therapeutics for the treatment of ALS.
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Affiliation(s)
- Poulomee Bose
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada
- Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM Tour Viger R09-482), 900 Rue Saint Denis, Montréal, Quebec, H2X 0A9, Canada
| | - Elsa Tremblay
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada
- FRQS Group de recherche sur le system nerveux centrale, Montreal, Canada
| | - Claudia Maios
- Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM Tour Viger R09-482), 900 Rue Saint Denis, Montréal, Quebec, H2X 0A9, Canada
| | - Vijay Narasimhan
- Zebrafish Centre for Advanced Drug Discovery and Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital and Department of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Gary A B Armstrong
- Department of Neurology and Neurosurgery, McGill University and Montreal Neurological Institute, Montreal, Canada
| | - Meijiang Liao
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada
- Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM Tour Viger R09-482), 900 Rue Saint Denis, Montréal, Quebec, H2X 0A9, Canada
| | - J Alex Parker
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada
- Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM Tour Viger R09-482), 900 Rue Saint Denis, Montréal, Quebec, H2X 0A9, Canada
| | - Richard Robitaille
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada
- FRQS Group de recherche sur le system nerveux centrale, Montreal, Canada
| | - Xiao Yan Wen
- Zebrafish Centre for Advanced Drug Discovery and Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital and Department of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Pierre Drapeau
- Department of Neuroscience, Université de Montréal, Montréal, Quebec, Canada.
- Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM Tour Viger R09-482), 900 Rue Saint Denis, Montréal, Quebec, H2X 0A9, Canada.
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Stålberg E, van Dijk H, Falck B, Kimura J, Neuwirth C, Pitt M, Podnar S, Rubin DI, Rutkove S, Sanders DB, Sonoo M, Tankisi H, Zwarts M. Standards for quantification of EMG and neurography. Clin Neurophysiol 2019; 130:1688-1729. [DOI: 10.1016/j.clinph.2019.05.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/07/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022]
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Study on variation trend of repetitive nerve stimulation waveform in amyotrophic lateral sclerosis. Chin Med J (Engl) 2019; 132:542-550. [PMID: 30807353 PMCID: PMC6415996 DOI: 10.1097/cm9.0000000000000117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease involving both upper and lower motor neurons with no effective cure. Electrophysiological studies have found decremental responses during low-frequency repetitive nerve stimulation (RNS) except for diffused neurogenic activities. However, the difference between ALS and generalized myasthenia gravis (GMG) in terms of waveform features is unclear. In the current study, we explored the variation trend of the amplitudes curve between ALS and GMG with low-frequency, positive RNS, and the possible mechanism is discussed preliminarily. METHODS A total of 85 ALS patients and 41 GMG patients were recruited. All patients were from Peking Union Medical College Hospital (PUMCH) between July 1, 2012 and February 28, 2015. RNS study included ulnar nerve, accessory nerve and facial nerve at 3 Hz and 5 Hz stimulation. The percentage reduction in the amplitude of the fourth or fifth wave from the first wave was calculated and compared with the normal values of our hospital. A 15% decrease in amplitude is defined as a decrease in amplitude. RESULTS The decremental response at low-frequency RNS showed the abnormal rate of RNS decline was 54.1% (46/85) in the ALS group, and the results of different nerves were 54.1% (46/85) of the accessory nerve, 8.2% (7/85) of the ulnar nerve and 0% (0/85) of the facial nerve stimulation, respectively. In the GMG group, the abnormal rate of RNS decline was 100% (41/41) at low-frequency RNS of accessory nerves. However, there was a significant difference between the 2 groups in the amplitude after the sixth wave. CONCLUSIONS Both groups of patients are able to show a decreasing amplitude of low-frequency stimulation RNS, but the recovery trend after the sixth wave has significant variation. It implies the different pathogenesis of NMJ dysfunction of these 2 diseases.
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Slater CR. 'Fragmentation' of NMJs: a sign of degeneration or regeneration? A long journey with many junctions. Neuroscience 2019; 439:28-40. [PMID: 31129203 DOI: 10.1016/j.neuroscience.2019.05.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
Mammalian neuromuscular junctions (NMJs) often consist of curved bands of synaptic contact, about 3-6 μm wide, which resemble pretzels. This contrasts with the NMJs of most animal species which consist of a cluster of separate synaptic spots, each of which is also about 3-6 μm across. In a number of situations, including a variety of disease states as well as normal ageing, mammalian NMJs acquire a more 'fragmented' appearance that resembles somewhat that of other species. This 'fragmentation' of the NMJ has sometimes been interpreted as a 'disintegration' or 'degeneration', with the suggestion that it might be associated with impaired neuromuscular transmission. An alternative view is that NMJ fragmentation is the outcome of a normal process by which the NMJ is maintained in an effective state. In this highly personal commentary, I cite a number of examples of this and point out that although the 'pretzel' form arises during normal development as a result of the sculpting of an immature synaptic 'plaque', in virtually all situations where new synaptic contact is established in adult mammals this occurs by the addition of new synaptic 'spots' rather than by the extension, or neoformation, of 'pretzels'. Further, where appropriate studies have been performed, no evidence of a correlation between the degree of fragmentation and the efficacy of transmission has emerged. It may therefore be more appropriate to consider NMJ 'fragmentation' as a form of regeneration, rather than of degeneration. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Clarke R Slater
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
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21
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Thams S, Lowry ER, Larraufie MH, Spiller KJ, Li H, Williams DJ, Hoang P, Jiang E, Williams LA, Sandoe J, Eggan K, Lieberam I, Kanning KC, Stockwell BR, Henderson CE, Wichterle H. A Stem Cell-Based Screening Platform Identifies Compounds that Desensitize Motor Neurons to Endoplasmic Reticulum Stress. Mol Ther 2019; 27:87-101. [PMID: 30446391 PMCID: PMC6318783 DOI: 10.1016/j.ymthe.2018.10.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 10/07/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease selectively targeting motor neurons in the brain and spinal cord. The reasons for differential motor neuron susceptibility remain elusive. We developed a stem cell-based motor neuron assay to study cell-autonomous mechanisms causing motor neuron degeneration, with implications for ALS. A small-molecule screen identified cyclopiazonic acid (CPA) as a stressor to which stem cell-derived motor neurons were more sensitive than interneurons. CPA induced endoplasmic reticulum stress and the unfolded protein response. Furthermore, CPA resulted in an accelerated degeneration of motor neurons expressing human superoxide dismutase 1 (hSOD1) carrying the ALS-causing G93A mutation, compared to motor neurons expressing wild-type hSOD1. A secondary screen identified compounds that alleviated CPA-mediated motor neuron degeneration: three kinase inhibitors and tauroursodeoxycholic acid (TUDCA), a bile acid derivative. The neuroprotective effects of these compounds were validated in human stem cell-derived motor neurons carrying a mutated SOD1 allele (hSOD1A4V). Moreover, we found that the administration of TUDCA in an hSOD1G93A mouse model of ALS reduced muscle denervation. Jointly, these results provide insights into the mechanisms contributing to the preferential susceptibility of ALS motor neurons, and they demonstrate the utility of stem cell-derived motor neurons for the discovery of new neuroprotective compounds.
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Affiliation(s)
- Sebastian Thams
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA.
| | - Emily Rhodes Lowry
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Marie-Hélène Larraufie
- Department of Biological Sciences and Department of Chemistry, Columbia University, Northwest Corner Building, MC4846, 550 West 120th Street, New York, NY 10027, USA
| | - Krista J Spiller
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Hai Li
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Damian J Williams
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, 650 West 168th Street, New York, NY, USA
| | - Phuong Hoang
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Elise Jiang
- Department of Biological Sciences and Department of Chemistry, Columbia University, Northwest Corner Building, MC4846, 550 West 120th Street, New York, NY 10027, USA
| | - Luis A Williams
- Department of Stem Cell and Regenerative Biology, Harvard University, MA 02138, USA
| | - Jackson Sandoe
- Department of Stem Cell and Regenerative Biology, Harvard University, MA 02138, USA
| | - Kevin Eggan
- Department of Stem Cell and Regenerative Biology, Harvard University, MA 02138, USA
| | - Ivo Lieberam
- Centre for Stem Cells and Regenerative Medicine and MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 9RT, UK
| | - Kevin C Kanning
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Brent R Stockwell
- Department of Biological Sciences and Department of Chemistry, Columbia University, Northwest Corner Building, MC4846, 550 West 120th Street, New York, NY 10027, USA
| | - Christopher E Henderson
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Hynek Wichterle
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA; Departments of Neuroscience, Rehabilitation and Regenerative Medicine, and Neurology, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA.
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Sun XS, Liu WX, Chen ZH, Ling L, Yang F, Wang HF, Cui F, Huang XS. Repetitive Nerve Stimulation in Amyotrophic Lateral Sclerosis. Chin Med J (Engl) 2018; 131:2146-2151. [PMID: 30203787 PMCID: PMC6144859 DOI: 10.4103/0366-6999.240798] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Nowadays, it is widely known that decremental responses in low-frequency repetitive nerve stimulation (LF-RNS) are frequently observed in patients with amyotrophic lateral sclerosis (ALS). The pathological mechanism of this phenomenon remains unknown. This study aimed to illuminate the features of RNS in Chinese patients with ALS. Methods Clinical and electrophysiological data of 146 probable and definite ALS patients who underwent RNS were retrospectively enrolled and analyzed. LF-RNS (3 Hz) was performed in trapezius, deltoid, abductor digiti minimi (ADM), quadriceps femoris, and tibialis anterior. High-frequency RNS (HF-RNS, 10 Hz) was performed only in ADM. The two-sample t-test and Chi-squared test were used for statistical analysis. Results Decremental responses to LF-RNS (≥10%) in at least one muscle were detected in 83 (56.8%) of the cases and were most commonly seen in trapezius and deltoid. The incidence of decremental response was higher in patients with upper limb onset. Incremental responses to HF-RNS (≥60%) in ADM were observed in 6 (5.6%) of the cases. In 106 muscles with decremental response, 62 (57.4%) muscles had a continuous decremental pattern, more than a U-shape pattern (37 cases, 34.3%). Nineteen cases showed definite decrements in LF-RNS tests in trapezius, while no abnormalities were found in the electromyography and neurological examination of the sternocleidomastoid muscle, supplied by the accessory nerve as well. Conclusions Decremental responses in the RNS are commonly observed in ALS patients. The findings regarding the trapezius indicated that some ALS onsets could be initiated by a "dying back" process, with destruction of neuromuscular junctions (NMJs) before motor neurons. Incremental responses in the ADM implied damage of the NMJs involved both the post and presynaptic membranes.
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Affiliation(s)
- Xiao-Sun Sun
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Wen-Xiu Liu
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Zhao-Hui Chen
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Li Ling
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Fei Yang
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Hong-Fen Wang
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Fang Cui
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
| | - Xu-Sheng Huang
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
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Kjældgaard AL, Pilely K, Olsen KS, Pedersen SW, Lauritsen AØ, Møller K, Garred P. Amyotrophic lateral sclerosis: The complement and inflammatory hypothesis. Mol Immunol 2018; 102:14-25. [PMID: 29933890 DOI: 10.1016/j.molimm.2018.06.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/15/2018] [Accepted: 06/06/2018] [Indexed: 12/28/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating, neurodegenerative motor neuron disease. The aetiology of ALS remains an enigma which hinders the design of an effective treatment to prevent, postpone, or reverse the pathophysiological changes occurring during the aggressive progression of this disease. During the last decade, basic research within the innate immune system, and in particular the complement system, has revealed new, important roles of the innate immune system during development, homeostasis, and ageing within as well as outside the central nervous system. Several lines of evidence indicate that aberrant activation of the complement system locally in the central nervous system as well as systemically may be involved in the pathophysiology of ALS. This exciting new knowledge could point towards the innate immune system as a potential target of medical intervention in ALS. Recently, the historic perception of ALS as a central neurodegenerative disease has been challenged due to the significant amount of evidence of a dying-back mechanism causing the selective destruction of the motor neurons, indicating that disease onset occurs outside the borders of the blood-brain-barrier. This review addresses the function of the innate immune system during ALS. We emphasize the role of the complement system and specifically suggest the involvement of ficolin-3 from the lectin pathway in the pathophysiology of ALS.
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Affiliation(s)
- Anne-Lene Kjældgaard
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Diagnostic Centre, Section 7631; Department of Neuroanaesthesiology.
| | - Katrine Pilely
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Diagnostic Centre, Section 7631
| | | | - Stephen Wørlich Pedersen
- Department of Neurology, Neuroscience Centre, Rigshospitalet, Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | | | | | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Diagnostic Centre, Section 7631
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25
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Patten SA, Aggad D, Martinez J, Tremblay E, Petrillo J, Armstrong GA, La Fontaine A, Maios C, Liao M, Ciura S, Wen XY, Rafuse V, Ichida J, Zinman L, Julien JP, Kabashi E, Robitaille R, Korngut L, Parker JA, Drapeau P. Neuroleptics as therapeutic compounds stabilizing neuromuscular transmission in amyotrophic lateral sclerosis. JCI Insight 2017; 2:97152. [PMID: 29202456 DOI: 10.1172/jci.insight.97152] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 10/17/2017] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressing, fatal disorder with no effective treatment. We used simple genetic models of ALS to screen phenotypically for potential therapeutic compounds. We screened libraries of compounds in C. elegans, validated hits in zebrafish, and tested the most potent molecule in mice and in a small clinical trial. We identified a class of neuroleptics that restored motility in C. elegans and in zebrafish, and the most potent was pimozide, which blocked T-type Ca2+ channels in these simple models and stabilized neuromuscular transmission in zebrafish and enhanced it in mice. Finally, a short randomized controlled trial of sporadic ALS subjects demonstrated stabilization of motility and evidence of target engagement at the neuromuscular junction. Simple genetic models are, thus, useful in identifying promising compounds for the treatment of ALS, such as neuroleptics, which may stabilize neuromuscular transmission and prolong survival in this disease.
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Affiliation(s)
- Shunmoogum A Patten
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada.,INRS Institut Armand-Frappier, Laval, Canada
| | - Dina Aggad
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada.,Institut des Biomolécules Max Mousseron IBMM, UMR 5247, CNRS-Université Montpellier-ENSCM, Montpellier, France
| | - Jose Martinez
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Elsa Tremblay
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,FRQS Groupe de recherche sur le système nerveux central, Montreal, Canada
| | - Janet Petrillo
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Gary Ab Armstrong
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada.,Department of Neurology and Neurosurgery, McGill University and Montreal Neurological Institute, Montreal, Canada
| | - Alexandre La Fontaine
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,FRQS Groupe de recherche sur le système nerveux central, Montreal, Canada
| | - Claudia Maios
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Meijiang Liao
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Sorana Ciura
- Sorbonne Université, Université Pierre et Marie Curie (UPMC), Université de Paris 06, Institut du Cerveau et de la Moelle Épinière (ICM), Paris, France
| | - Xiao-Yan Wen
- Zebrafish Centre for Advanced Drug Discovery & Keenan Research Centre for Biomedical Science, Li Ka Sheng Knowledge Institute, St. Michael's Hospital and Department of Medicine & Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Victor Rafuse
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Justin Ichida
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine and Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California, Los Angeles, California, USA
| | - Lorne Zinman
- Department of Neurology, University of Toronto, Sunnybrook Health Sciences Centre,Toronto, Ontario, Canada
| | - Jean-Pierre Julien
- Centre de recherche CERVO, Chemin de la Canardière, Université Laval, Québec City, Canada
| | - Edor Kabashi
- Sorbonne Université, Université Pierre et Marie Curie (UPMC), Université de Paris 06, Institut du Cerveau et de la Moelle Épinière (ICM), Paris, France
| | - Richard Robitaille
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,FRQS Groupe de recherche sur le système nerveux central, Montreal, Canada
| | - Lawrence Korngut
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - J Alexander Parker
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada
| | - Pierre Drapeau
- Department of Neuroscience, Université de Montréal, Montréal, Canada.,Centre de recherche du centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Canada.,FRQS Groupe de recherche sur le système nerveux central, Montreal, Canada
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Perry S, Han Y, Das A, Dickman D. Homeostatic plasticity can be induced and expressed to restore synaptic strength at neuromuscular junctions undergoing ALS-related degeneration. Hum Mol Genet 2017; 26:4153-4167. [PMID: 28973139 PMCID: PMC5886083 DOI: 10.1093/hmg/ddx304] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/09/2017] [Accepted: 07/26/2017] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is debilitating neurodegenerative disease characterized by motor neuron dysfunction and progressive weakening of the neuromuscular junction (NMJ). Hereditary ALS is strongly associated with variants in the human C9orf72 gene. We have characterized C9orf72 pathology at the Drosophila NMJ and utilized several approaches to restore synaptic strength in this model. First, we demonstrate a dramatic reduction in synaptic arborization and active zone number at NMJs following C9orf72 transgenic expression in motor neurons. Further, neurotransmission is similarly reduced at these synapses, consistent with severe degradation. However, despite these defects, C9orf72 synapses still retain the ability to express presynaptic homeostatic plasticity, a fundamental and adaptive form of NMJ plasticity in which perturbation to postsynaptic neurotransmitter receptors leads to a retrograde enhancement in presynaptic release. Next, we show that these endogenous but dormant homeostatic mechanisms can be harnessed to restore synaptic strength despite C9orf72 pathogenesis. Finally, activation of regenerative signaling is not neuroprotective in motor neurons undergoing C9orf72 toxicity. Together, these experiments define synaptic dysfunction at NMJs experiencing ALS-related degradation and demonstrate the potential to activate latent plasticity as a novel therapeutic strategy to restore synaptic strength.
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Affiliation(s)
- Sarah Perry
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
- USC Neuroscience Graduate Program, Los Angeles, CA 90089, USA
| | - Anushka Das
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
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27
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Opposite Synaptic Alterations at the Neuromuscular Junction in an ALS Mouse Model: When Motor Units Matter. J Neurosci 2017; 37:8901-8918. [PMID: 28821658 DOI: 10.1523/jneurosci.3090-16.2017] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 06/29/2017] [Accepted: 08/02/2017] [Indexed: 12/13/2022] Open
Abstract
Denervation of the neuromuscular junction (NMJ) precedes the loss of motor neurons (MNs) in amyotrophic lateral sclerosis (ALS). ALS is characterized by a motor unit (MU)-dependent vulnerability where MNs with fast-fatigable (FF) characteristics are lost first, followed by fast fatigue-resistant (FR) and slow (S) MNs. However, changes in NMJ properties as a function of MU types remain debated. We hypothesized that NMJ synaptic functions would be altered precociously in an MU-specific manner, before structural alterations of the NMJ. Synaptic transmission and morphological changes of NMJs have been explored in two nerve-muscle preparations of male SOD1G37R mice and their wild-type (WT) littermates: the soleus (S and FR MU); and the extensor digitorum longus (FF MU). S, FR, and FF NMJs of WT mice showed distinct synaptic properties from which we build an MU synaptic profile (MUSP) that reports MU-dependent NMJ synaptic properties. At postnatal day 180 (P180), FF and S NMJs of SOD1 already showed, respectively, lower and higher quantal content compared with WT mice, before signs of MN death and before NMJ morphological alterations. Changes persisted in both muscles until preonset (P380), while denervation was frequent in the mutant mouse. MN death was evident at this stage. Additional changes occurred at clinical disease onset (P450) for S and FR MU. As a whole, our results reveal a reversed MUSP in SOD1 mutants and highlight MU-specific synaptic changes occurring in a precise temporal sequence. Importantly, changes in synaptic properties appear to be good predictors of vulnerability to neurodegeneration.SIGNIFICANCE STATEMENT The inadequate excitability of motor neurons and their output, the neuromuscular junctions (NMJs), has been considered a key factor in the detrimental outcome of the motor function in amyotrophic lateral sclerosis. However, a conundrum persists at the NMJ whereby persistent but incoherent opposite neurotransmission changes have been reported to take place. This article untangles this conundrum by systematically analyzing the changes in synaptic properties over the course of the disease progression as a function of the motor unit type. This temporal analysis reveals that early synaptic alterations evolve with disease progression but precede NMJ neurodegeneration. These data provide a novel framework of analysis and comparison of synaptic transmission alterations in neurodegenerative disorders.
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29
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Nijssen J, Comley LH, Hedlund E. Motor neuron vulnerability and resistance in amyotrophic lateral sclerosis. Acta Neuropathol 2017; 133:863-885. [PMID: 28409282 PMCID: PMC5427160 DOI: 10.1007/s00401-017-1708-8] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/29/2017] [Accepted: 04/01/2017] [Indexed: 12/11/2022]
Abstract
In the fatal disease-amyotrophic lateral sclerosis (ALS)-upper (corticospinal) motor neurons (MNs) and lower somatic MNs, which innervate voluntary muscles, degenerate. Importantly, certain lower MN subgroups are relatively resistant to degeneration, even though pathogenic proteins are typically ubiquitously expressed. Ocular MNs (OMNs), including the oculomotor, trochlear and abducens nuclei (CNIII, IV and VI), which regulate eye movement, persist throughout the disease. Consequently, eye-tracking devices are used to enable paralysed ALS patients (who can no longer speak) to communicate. Additionally, there is a gradient of vulnerability among spinal MNs. Those innervating fast-twitch muscle are most severely affected and degenerate first. MNs innervating slow-twitch muscle can compensate temporarily for the loss of their neighbours by re-innervating denervated muscle until later in disease these too degenerate. The resistant OMNs and the associated extraocular muscles (EOMs) are anatomically and functionally very different from other motor units. The EOMs have a unique set of myosin heavy chains, placing them outside the classical characterization spectrum of all skeletal muscle. Moreover, EOMs have multiple neuromuscular innervation sites per single myofibre. Spinal fast and slow motor units show differences in their dendritic arborisations and the number of myofibres they innervate. These motor units also differ in their functionality and excitability. Identifying the molecular basis of cell-intrinsic pathways that are differentially activated between resistant and vulnerable MNs could reveal mechanisms of selective neuronal resistance, degeneration and regeneration and lead to therapies preventing progressive MN loss in ALS. Illustrating this, overexpression of OMN-enriched genes in spinal MNs, as well as suppression of fast spinal MN-enriched genes can increase the lifespan of ALS mice. Here, we discuss the pattern of lower MN degeneration in ALS and review the current literature on OMN resistance in ALS and differential spinal MN vulnerability. We also reflect upon the non-cell autonomous components that are involved in lower MN degeneration in ALS.
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30
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Copy Number Variations in Amyotrophic Lateral Sclerosis: Piecing the Mosaic Tiles Together through a Systems Biology Approach. Mol Neurobiol 2017; 55:1299-1322. [PMID: 28120152 PMCID: PMC5820374 DOI: 10.1007/s12035-017-0393-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/06/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating and still untreatable motor neuron disease. Despite the molecular mechanisms underlying ALS pathogenesis that are still far from being understood, several studies have suggested the importance of a genetic contribution in both familial and sporadic forms of the disease. In addition to single-nucleotide polymorphisms (SNPs), which account for only a limited number of ALS cases, a consistent number of common and rare copy number variations (CNVs) have been associated to ALS. Most of the CNV-based association studies use a traditional candidate-gene approach that is inadequate for uncovering the genetic architectures of complex traits like ALS. The emergent paradigm of “systems biology” may offer a new perspective to better interpret the wide spectrum of CNVs in ALS, enabling the characterization of the complex network of gene products underlying ALS pathogenesis. In this review, we will explore the landscape of CNVs in ALS, putting specific emphasis on the functional impact of common CNV regions and genes consistently associated with increased risk of developing disease. In addition, we will discuss the potential contribution of multiple rare CNVs in ALS pathogenesis, focusing our attention on the complex mechanisms by which these proteins might impact, individually or in combination, the genetic susceptibility of ALS. The comprehensive detection and functional characterization of common and rare candidate risk CNVs in ALS susceptibility may bring new pieces into the intricate mosaic of ALS pathogenesis, providing interesting and important implications for a more precise molecular biomarker-assisted diagnosis and more effective and personalized treatments.
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31
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Abstract
The motor unit comprises the anterior horn cell, its axon, and the muscle fibers that it innervates. Although the true number of motor units is unknown, the number of motor units appears to vary greatly between different muscles and between different individuals. Assessment of the number and function of motor units is needed in diseases of the anterior horn cell and other motor nerve disorders. Amyotrophic lateral sclerosis is the most important disease of anterior horn cells. The need for an effective biomarker for assessing disease progression and for use in clinical trials in amyotrophic lateral sclerosis has stimulated the study of methods to measure the number of motor units. Since 1970 a number of different methods, including the incremental, F-wave, multipoint, and statistical methods, have been developed but none has achieved widespread applicability. Two methods (MUNIX and the multipoint incremental method) are in current use across multiple centres and are discussed in detail in this review, together with other recently published methods. Imaging with magnetic resonance and ultrasound is increasingly being applied to this area. Motor unit number estimates have also been applied to other neuromuscular diseases such as spinal muscular atrophy, compression neuropathies, and prior poliomyelitis. The need for an objective measure for the assessment of motor units remains tantalizingly close but unfulfilled in 2016.
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Affiliation(s)
- Robert D Henderson
- Department of Neurology, Royal Brisbane & Women's Hospital and University of Queensland Centre for Clinical Research, Herston, Brisbane, 4006, Australia.
| | - Pamela A McCombe
- Department of Neurology, Royal Brisbane & Women's Hospital and University of Queensland Centre for Clinical Research, Herston, Brisbane, 4006, Australia
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32
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Miralles F. Modelling the response to low-frequency repetitive nerve stimulation of myasthenia gravis and Lambert-Eaton myasthenic syndrome. Med Biol Eng Comput 2016; 54:1761-1778. [PMID: 27016366 DOI: 10.1007/s11517-016-1462-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 01/29/2016] [Indexed: 10/22/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune postsynaptic disorder of neuromuscular transmission caused, in most patients, by antibodies against postsynaptic acetylcholine receptors. Lambert-Eaton myasthenic syndrome (LEMS) is a presynaptic autoimmune disease in which there is a reduction in Ca2+ entry with each impulse due to the action of antibodies against Ca2+ channels. These diseases have a distinct pattern of response to low-frequency repetitive nerve stimulation which allows its recognition in a particular subject. Nevertheless, the physiologic basis of this response is not entirely known. A model of the time-course of release probability of neuromuscular junctions that incorporates facilitation and a depression-recovery mechanism has been developed with the aim to investigate these response patterns. When the basal value of release probability was in the physiologic range, as in MG, release probability showed an increment after its initial decrease only if the recovery from depression was accelerated by presynaptic residual Ca2+. Otherwise, when the basal release probability was low, as in LEMS, a progressive reduction in the release probability without any late increase was only obtained if the efficacy of Facilitation and Ca2+-dependent recovery from depression were reduced.
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Affiliation(s)
- Francesc Miralles
- Unitat de Patologia Neuromuscular, Servei de Neurologia, Hospital Universitari Son Espases, Carretera de Valldemossa, 79, 07010, Palma De Mallorca, Illes Balears, Spain.
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Ng F, Lee DC, Schrumpf LA, Mazurek ME, Lee Lo V, Gill SK, Maselli RA. Effect of 3,4-diaminopyridine at the murine neuromuscular junction. Muscle Nerve 2016; 55:223-231. [PMID: 27251582 DOI: 10.1002/mus.25208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/19/2016] [Accepted: 05/31/2016] [Indexed: 11/09/2022]
Abstract
INTRODUCTION We investigated the effects of 3,4-diaminopyridine (3,4-DAP) and its acetylated metabolite, N-(4-amino-pyridin-3-yl) acetamide (3-Ac), at the mammalian neuromuscular junction. METHODS Quantal release of acetylcholine was studied in diaphragm muscles of mice, using in vitro intracellular microelectrode recordings. RESULTS Under conditions of low probability of release, 3,4-DAP produced a 1,000% increase in quantal release, but 3-Ac had no effect. Under conditions of normal probability of release, the effect of 3,4-DAP was modest and limited by concurrent depletion of synaptic vesicles, especially with high concentrations of 3,4-DAP and high frequencies of nerve stimulation. CONCLUSIONS These findings predict 3,4-DAP is most effective in conditions with low probability of quantal release, such as Lambert-Eaton myasthenic syndrome. A beneficial effect is also expected in disorders of neuromuscular transmission in which the effect of 3,4-DAP on quantal release is not limited by depletion of synaptic vesicles, such as postsynaptic congenital myasthenic syndromes. Muscle Nerve, 2016 Muscle Nerve 55: 223-231, 2017.
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Affiliation(s)
- Fiona Ng
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Diana C Lee
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Leah A Schrumpf
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Mary E Mazurek
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Victoria Lee Lo
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Sharleen K Gill
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Ricardo A Maselli
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
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Mori A, Yamashita S, Nakajima M, Hori H, Tawara A, Matsuo Y, Misumi Y, Ando Y. CMAP decrement as a potential diagnostic marker for ALS. Acta Neurol Scand 2016; 134:49-53. [PMID: 26434688 DOI: 10.1111/ane.12510] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2015] [Indexed: 12/11/2022]
Abstract
OBJECTIVE We previously reported that decrement of compound muscle action potential (CMAP) by repetitive nerve stimulation (RNS) was greater in the median nerves than in the ulnar nerves of patients with amyotrophic lateral sclerosis (ALS). The aim of this study was to evaluate whether CMAP decrement by RNS is a feasible marker for the differentiation of ALS from other diseases. MATERIALS & METHODS We performed RNS in the median and ulnar nerves of 51 patients with ALS and 40 patients with other diseases. RESULTS The CMAP decrement was significantly greater in the median nerves of patients with ALS, compared to the disease control patients. In the median nerves of patients with ALS, CMAP decrement was significantly greater in the cervical region-onset group than in the other region-onset group. CONCLUSIONS The finding of CMAP decrement in the median nerves can be useful for differentiating ALS patients with cervical region onset from other controls with active neuropathic diseases.
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Affiliation(s)
- A. Mori
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - S. Yamashita
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - M. Nakajima
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - H. Hori
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - A. Tawara
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - Y. Matsuo
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - Y. Misumi
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
| | - Y. Ando
- Department of Neurology; Graduate School of Medical Sciences; Kumamoto University; Chuo-ku Kumamoto Japan
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35
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Casas C, Manzano R, Vaz R, Osta R, Brites D. Synaptic Failure: Focus in an Integrative View of ALS. Brain Plast 2016; 1:159-175. [PMID: 29765840 PMCID: PMC5928542 DOI: 10.3233/bpl-140001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
From early description by Charcot, the classification of the Amyotrophic Lateral Sclerosis (ALS) is evolving from a subtype of Motor Neuron (MN) Disease to be considered rather a multi-systemic, non-cell autonomous and complex neurodegenerative disease. In the last decade, the huge amount of knowledge acquired has shed new insights on the pathological mechanisms underlying ALS from different perspectives. However, a whole vision on the multiple dysfunctional pathways is needed with the inclusion of information often excluded in other published revisions. We propose an integrative view of ALS pathology, although centered on the synaptic failure as a converging and crucial player to the etiology of the disease. Homeostasis of input and output synaptic activity of MNs has been proved to be severely and early disrupted and to definitively contribute to microcircuitry alterations at the spinal cord. Several cells play roles in synaptic communication across the MNs network system such as interneurons, astrocytes, microglia, Schwann and skeletal muscle cells. Microglia are described as highly dynamic surveying cells of the nervous system but also as determinant contributors to the synaptic plasticity linked to neuronal activity. Several signaling axis such as TNFα/TNFR1 and CX3CR1/CX3CL1 that characterize MN-microglia cross talk contribute to synaptic scaling and maintenance, have been found altered in ALS. The presence of dystrophic and atypical microglia in late stages of ALS, with a decline in their dynamic motility and phagocytic ability, together with less synaptic and neuronal contacts disrupts the MN-microglia dialogue, decreases homeostatic regulation of neuronal activity, perturbs “on/off” signals and accelerates disease progression associated to impaired synaptic function and regeneration. Other hotspot in the ALS affected network system is the unstable neuromuscular junction (NMJ) leading to distal axonal degeneration. Reduced neuromuscular spontaneous synaptic activity in ALS mice models was also suggested to account for the selective vulnerability of MNs and decreased regenerative capability. Synaptic destabilization may as well derive from increased release of molecules by muscle cells (e.g. NogoA) and by terminal Schwann cells (e.g. semaphorin 3A) conceivably causing nerve terminal retraction and denervation, as well as inhibition of re-connection to muscle fibers. Indeed, we have overviewed the alterations on the metabolic pathways and self-regenerative capacity presented in skeletal muscle cells that contribute to muscle wasting in ALS. Finally, a detailed footpath of pathologic changes on MNs and associated dysfunctional and synaptic alterations is provided. The oriented motivation in future ALS studies as outlined in the present article will help in fruitful novel achievements on the mechanisms involved and in developing more target-driven therapies that will bring new hope in halting or delaying disease progression in ALS patients.
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Affiliation(s)
- Caty Casas
- Group of Neuroplasticity and Regeneration, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Barcelona, Spain
| | - Raquel Manzano
- Laboratory of Genetic Biochemistry (LAGENBIO-I3A), Aragón Institute of Health Sciences, Universidad de Zaragoza, Zaragoza, Spain
| | - Rita Vaz
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa Lisbon, Portugal; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisbon, Portugal
| | - Rosario Osta
- Laboratory of Genetic Biochemistry (LAGENBIO-I3A), Aragón Institute of Health Sciences, Universidad de Zaragoza, Zaragoza, Spain
| | - Dora Brites
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa Lisbon, Portugal; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisbon, Portugal
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36
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Puttonen KA, Ruponen M, Naumenko N, Hovatta OH, Tavi P, Koistinaho J. Generation of Functional Neuromuscular Junctions from Human Pluripotent Stem Cell Lines. Front Cell Neurosci 2015; 9:473. [PMID: 26696831 PMCID: PMC4672046 DOI: 10.3389/fncel.2015.00473] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/20/2015] [Indexed: 12/12/2022] Open
Abstract
Several neuromuscular diseases involve dysfunction of neuromuscular junctions (NMJs), yet there are no patient-specific human models for electrophysiological characterization of NMJ. We seeded cells of neurally-induced embryoid body-like spheres derived from induced pluripotent stem cell (iPSC) or embryonic stem cell (ESC) lines as monolayers without basic fibroblast factor (bFGF) and observed differentiation of neuronal as well as spontaneously contracting, multinucleated skeletal myotubes. The myotubes showed striation, immunoreactivity for myosin heavy chain, actin bundles typical for myo-oriented cells, and generated spontaneous and evoked action potentials (APs). The myogenic differentiation was associated with expression of MyoD1, myogenin and type I ryanodine receptor. Neurons formed end plate like structures with strong binding of α-bungarotoxin, a marker of nicotinic acetylcholine receptors highly expressed in the postsynaptic membrane of NMJs, and expressed SMI-32, a motoneuron marker, as well as SV2, a marker for synapses. Pharmacological stimulation of cholinergic receptors resulted in strong depolarization of myotube membrane and raised Ca2+ concentration in sarcoplasm, while electrical stimulation evoked Ca2+ transients in myotubes. Stimulation of motoneurons with N-Methyl-D-aspartate resulted in reproducible APs in myotubes and end plates displayed typical mEPPs and tonic activity depolarizing myotubes of about 10 mV. We conclude that simultaneous differentiation of neurons and myotubes from patient-specific iPSCs or ESCs results also in the development of functional NMJs. Our human model of NMJ may serve as an important tool to investigate normal development, mechanisms of diseases and novel drug targets involving NMJ dysfunction and degeneration.
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Affiliation(s)
- Katja A Puttonen
- Department of Neurobiology, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Marika Ruponen
- Department of Neurobiology, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland ; School of Pharmacy, University of Eastern Finland Kuopio, Finland
| | - Nikolay Naumenko
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Outi H Hovatta
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet Stockholm, Sweden
| | - Pasi Tavi
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Jari Koistinaho
- Department of Neurobiology, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
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Comley LH, Nijssen J, Frost-Nylen J, Hedlund E. Cross-disease comparison of amyotrophic lateral sclerosis and spinal muscular atrophy reveals conservation of selective vulnerability but differential neuromuscular junction pathology. J Comp Neurol 2015; 524:1424-42. [PMID: 26502195 PMCID: PMC5063101 DOI: 10.1002/cne.23917] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 10/16/2015] [Accepted: 10/22/2015] [Indexed: 12/13/2022]
Abstract
Neuromuscular junctions are primary pathological targets in the lethal motor neuron diseases spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). Synaptic pathology and denervation of target muscle fibers has been reported prior to the appearance of clinical symptoms in mouse models of both diseases, suggesting that neuromuscular junctions are highly vulnerable from the very early stages, and are a key target for therapeutic intervention. Here we examined neuromuscular pathology longitudinally in three clinically relevant muscle groups in mouse models of ALS and SMA in order to assess their relative vulnerabilities. We show for the first time that neuromuscular junctions of the extraocular muscles (responsible for the control of eye movement) were resistant to degeneration in endstage SMA mice, as well as in late symptomatic ALS mice. Tongue muscle neuromuscular junctions were also spared in both animal models. Conversely, neuromuscular junctions of the lumbrical muscles of the hind‐paw were vulnerable in both SMA and ALS, with a loss of neuronal innervation and shrinkage of motor endplates in both diseases. Thus, the pattern of selective vulnerability was conserved across these two models of motor neuron disease. However, the first evidence of neuromuscular pathology occurred at different timepoints of disease progression, with much earlier evidence of presynaptic involvement in ALS, progressing to changes on the postsynaptic side. Conversely, in SMA changes appeared concomitantly at the neuromuscular junction, suggesting that mechanisms of neuromuscular disruption are distinct in these diseases. J. Comp. Neurol. 524:1424–1442, 2016. © 2015 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Laura H Comley
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jik Nijssen
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | | | - Eva Hedlund
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Panitz S, Kornhuber M, Hanisch F. The checklist individual strength (CIS20-R) in patients with amyotrophic lateral sclerosis - a longitudinal study. Acta Neurol Scand 2015; 131:372-80. [PMID: 25639482 DOI: 10.1111/ane.12349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Fatigue may be underestimated symptom in amyotrophic lateral sclerosis (ALS). The self-administered checklist individual strength (CIS20-R) was used to measure both physical and mental fatigue in ALS. MATERIALS AND METHODS Fatigue was measured in 51 consecutive patients with ALS using the fatigue severity scale (FSS) and the CIS20-R (four dimensions: subjective fatigue experience, concentration, motivation, activity). The questionnaire scores were compared with disease and progression parameters [revised ALS functional rating scale (ALS-FRS-R), MRC sum score, slow vital capacity (slow VC)]. Patients had follow-ups at six and 12 months. RESULTS At baseline (mean age: 57.9 years ± 12.3, mean disease duration: 15.8 months ± 12.7) clinical relevant fatigue was seen in 49% in FSS and 40% in CIS20-R. FSS and CIS20-R (except the subscale for concentration) were steadily increasing in the course of the disease. CIS1 (subjective fatigue) but not FSS showed a correlation to the ALS-FRS-R and the progression of the ALS-FRS-R after 12 months. There was a moderate positive correlation between FSS and CIS20-R. CONCLUSIONS The CIS20-R is a sensitive tool to detect clinically relevant fatigue in early stages of ALS. Both physical and mental (motivation) dimensions of fatigue steadily increase during the course of the disease in ALS.
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Affiliation(s)
- S. Panitz
- Department of Neurology; Martin-Luther-University Halle-Wittenberg; Halle Saale Germany
| | - M. Kornhuber
- Department of Neurology; Martin-Luther-University Halle-Wittenberg; Halle Saale Germany
| | - F. Hanisch
- Department of Neurology; Martin-Luther-University Halle-Wittenberg; Halle Saale Germany
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Bruneteau G, Bauché S, Gonzalez de Aguilar JL, Brochier G, Mandjee N, Tanguy ML, Hussain G, Behin A, Khiami F, Sariali E, Hell-Remy C, Salachas F, Pradat PF, Lacomblez L, Nicole S, Fontaine B, Fardeau M, Loeffler JP, Meininger V, Fournier E, Koenig J, Hantaï D. Endplate denervation correlates with Nogo-A muscle expression in amyotrophic lateral sclerosis patients. Ann Clin Transl Neurol 2015; 2:362-72. [PMID: 25909082 PMCID: PMC4402082 DOI: 10.1002/acn3.179] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 01/01/2015] [Indexed: 12/01/2022] Open
Abstract
Objective Data from mouse models of amyotrophic lateral sclerosis (ALS) suggest early morphological changes in neuromuscular junctions (NMJs), with loss of nerve–muscle contact. Overexpression of the neurite outgrowth inhibitor Nogo-A in muscle may play a role in this loss of endplate innervation. Methods We used confocal and electron microscopy to study the structure of the NMJs in muscle samples collected from nine ALS patients (five early-stage patients and four long-term survivors). We correlated the morphological results with clinical and electrophysiological data, and with Nogo-A muscle expression level. Results Surface electromyography assessment of neuromuscular transmission was abnormal in 3/9 ALS patients. The postsynaptic apparatus was morphologically altered for almost all NMJs (n = 430) analyzed using confocal microscopy. 19.7% of the NMJs were completely denervated (fragmented synaptic gutters and absence of nerve terminal profile). The terminal axonal arborization was usually sparsely branched and 56.8% of innervated NMJs showed a typical reinnervation pattern. Terminal Schwann cell (TSC) morphology was altered with extensive cytoplasmic processes. A marked intrusion of TSCs in the synaptic cleft was seen in some cases, strikingly reducing the synaptic surface available for neuromuscular transmission. Finally, high-level expression of Nogo-A in muscle was significantly associated with higher extent of NMJ denervation and negative functional outcome. Interpretation Our results support the hypothesis that morphological alterations of NMJs are present from early-stage disease and may significantly contribute to functional motor impairment in ALS patients. Muscle expression of Nogo-A is associated with NMJ denervation and thus constitutes a therapeutic target to slow disease progression.
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Affiliation(s)
- Gaëlle Bruneteau
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France ; APHP, Hôpital Pitié-Salpêtrière, Département des Maladies du Système Nerveux, Centre référent SLA Paris, France ; APHP, INSERM, ICM, Centre d'Investigation Clinique Pitié Neurosciences, CIC-1422, Département des Maladies du Système Nerveux, Hôpital Pitié-Salpêtrière Paris, France
| | - Stéphanie Bauché
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Jose Luis Gonzalez de Aguilar
- Université de Strasbourg, UMR_S 1118 Strasbourg, France ; INSERM, U1118, Mécanismes Centraux et Périphériques de la Neurodégénérescence Strasbourg, France
| | - Guy Brochier
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Hôpital Pitié-Salpêtrière Paris, France ; APHP, Hôpital Pitié-Salpêtrière, Centre de référence de pathologie neuromusculaire Paris-Est, Institut de Myologie Paris, France
| | - Nathalie Mandjee
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Marie-Laure Tanguy
- AP-HP, Hôpital Pitié-Salpêtrière, Unité de Recherche Clinique Paris, France
| | - Ghulam Hussain
- Université de Strasbourg, UMR_S 1118 Strasbourg, France ; INSERM, U1118, Mécanismes Centraux et Périphériques de la Neurodégénérescence Strasbourg, France
| | - Anthony Behin
- APHP, Hôpital Pitié-Salpêtrière, Centre de référence de pathologie neuromusculaire Paris-Est, Institut de Myologie Paris, France
| | - Frédéric Khiami
- APHP, Hôpital Pitié-Salpêtrière, Service d'Orthopédie Paris, France
| | - Elhadi Sariali
- APHP, Hôpital Pitié-Salpêtrière, Service d'Orthopédie Paris, France
| | - Caroline Hell-Remy
- APHP, Hôpital Pitié-Salpêtrière, Département d'Anesthésie-Réanimation Paris, France
| | - François Salachas
- APHP, Hôpital Pitié-Salpêtrière, Département des Maladies du Système Nerveux, Centre référent SLA Paris, France
| | - Pierre-François Pradat
- APHP, Hôpital Pitié-Salpêtrière, Département des Maladies du Système Nerveux, Centre référent SLA Paris, France
| | - Lucette Lacomblez
- APHP, Hôpital Pitié-Salpêtrière, Département des Maladies du Système Nerveux, Centre référent SLA Paris, France
| | - Sophie Nicole
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Bertrand Fontaine
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Michel Fardeau
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Hôpital Pitié-Salpêtrière Paris, France
| | - Jean-Philippe Loeffler
- Université de Strasbourg, UMR_S 1118 Strasbourg, France ; INSERM, U1118, Mécanismes Centraux et Périphériques de la Neurodégénérescence Strasbourg, France
| | - Vincent Meininger
- APHP, Hôpital Pitié-Salpêtrière, Département des Maladies du Système Nerveux, Centre référent SLA Paris, France
| | - Emmanuel Fournier
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France ; APHP, Hôpital Pitié-Salpêtrière, Centre de référence de pathologie neuromusculaire Paris-Est, Institut de Myologie Paris, France
| | - Jeanine Koenig
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Daniel Hantaï
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France ; APHP, Hôpital Pitié-Salpêtrière, Centre de référence de pathologie neuromusculaire Paris-Est, Institut de Myologie Paris, France
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Brown R, Dissanayake KN, Skehel PA, Ribchester RR. Endomicroscopy and electromyography of neuromuscular junctions in situ. Ann Clin Transl Neurol 2014; 1:867-83. [PMID: 25540801 PMCID: PMC4265058 DOI: 10.1002/acn3.124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 12/12/2022] Open
Abstract
Objective Electromyography (EMG) is used routinely to diagnose neuromuscular dysfunction in a wide range of peripheral neuropathies, myopathies, and neuromuscular degenerative diseases including motor neuron diseases such as amyotrophic lateral sclerosis (ALS). Definitive neurological diagnosis may also be indicated by the analysis of pathological neuromuscular innervation in motor-point biopsies. Our objective in this study was to preempt motor-point biopsy by combining live imaging with electrophysiological analysis of slow degeneration of neuromuscular junctions (NMJs) in vivo. Methods We combined conventional needle electromyography with fiber-optic confocal endomicroscopy (CEM), using an integrated hand-held, 1.5-mm-diameter probe. We utilized as a test bed, various axotomized muscles in the hind limbs of anaesthetized, double-homozygous thy1.2YFP16: WldS mice, which coexpress the Wallerian-degeneration Slow (WldS) protein and yellow fluorescent protein (YFP) in motor neurons. We also tested exogenous vital stains, including Alexa488-α-bungarotoxin; the styryl pyridinium dye 4-Di-2-Asp; and a GFP conjugate of botulinum toxin Type A heavy chain (GFP-HcBoNT/A). Results We show that an integrated EMG/CEM probe is effective in longitudinal evaluation of functional and morphological changes that take place over a 7-day period during axotomy-induced, slow neuromuscular synaptic degeneration. EMG amplitude declined in parallel with overt degeneration of motor nerve terminals. EMG/CEM was safe and effective when nerve terminals and motor endplates were selectively stained with vital dyes. Interpretation Our findings constitute proof-of-concept, based on live imaging in an animal model, that combining EMG/CEM may be useful as a minimally invasive precursor or alternative to motor-point biopsy in neurological diagnosis and for monitoring local administration of potential therapeutics.
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Affiliation(s)
- Rosalind Brown
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Kosala N Dissanayake
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Paul A Skehel
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Richard R Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
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Ngo S, Steyn F, McCombe P. Body mass index and dietary intervention: Implications for prognosis of amyotrophic lateral sclerosis. J Neurol Sci 2014; 340:5-12. [DOI: 10.1016/j.jns.2014.02.035] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 02/21/2014] [Accepted: 02/25/2014] [Indexed: 12/12/2022]
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Machamer JB, Collins SE, Lloyd TE. The ALS gene FUS regulates synaptic transmission at the Drosophila neuromuscular junction. Hum Mol Genet 2014; 23:3810-22. [PMID: 24569165 DOI: 10.1093/hmg/ddu094] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mutations in the RNA binding protein Fused in sarcoma (FUS) are estimated to account for 5-10% of all inherited cases of amyotrophic lateral sclerosis (ALS), but the function of FUS in motor neurons is poorly understood. Here, we investigate the early functional consequences of overexpressing wild-type or ALS-associated mutant FUS proteins in Drosophila motor neurons, and compare them to phenotypes arising from loss of the Drosophila homolog of FUS, Cabeza (Caz). We find that lethality and locomotor phenotypes correlate with levels of FUS transgene expression, indicating that toxicity in developing motor neurons is largely independent of ALS-linked mutations. At the neuromuscular junction (NMJ), overexpression of either wild-type or mutant FUS results in decreased number of presynaptic active zones and altered postsynaptic glutamate receptor subunit composition, coinciding with a reduction in synaptic transmission as a result of both reduced quantal size and quantal content. Interestingly, expression of human FUS downregulates endogenous Caz levels, demonstrating that FUS autoregulation occurs in motor neurons in vivo. However, loss of Caz from motor neurons increases synaptic transmission as a result of increased quantal size, suggesting that the loss of Caz in animals expressing FUS does not contribute to motor deficits. These data demonstrate that FUS/Caz regulates NMJ development and plays an evolutionarily conserved role in modulating the strength of synaptic transmission in motor neurons.
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Affiliation(s)
| | | | - Thomas E Lloyd
- Department of Neurology, and The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Lecomte MJ, Bertolus C, Santamaria J, Bauchet AL, Herbin M, Saurini F, Misawa H, Maisonobe T, Pradat PF, Nosten-Bertrand M, Mallet J, Berrard S. Selective disruption of acetylcholine synthesis in subsets of motor neurons: a new model of late-onset motor neuron disease. Neurobiol Dis 2014; 65:102-11. [PMID: 24486622 DOI: 10.1016/j.nbd.2014.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 01/03/2014] [Accepted: 01/21/2014] [Indexed: 12/25/2022] Open
Abstract
Motor neuron diseases are characterized by the selective chronic dysfunction of a subset of motor neurons and the subsequent impairment of neuromuscular function. To reproduce in the mouse these hallmarks of diseases affecting motor neurons, we generated a mouse line in which ~40% of motor neurons in the spinal cord and the brainstem become unable to sustain neuromuscular transmission. These mice were obtained by conditional knockout of the gene encoding choline acetyltransferase (ChAT), the biosynthetic enzyme for acetylcholine. The mutant mice are viable and spontaneously display abnormal phenotypes that worsen with age including hunched back, reduced lifespan, weight loss, as well as striking deficits in muscle strength and motor function. This slowly progressive neuromuscular dysfunction is accompanied by muscle fiber histopathological features characteristic of neurogenic diseases. Unexpectedly, most changes appeared with a 6-month delay relative to the onset of reduction in ChAT levels, suggesting that compensatory mechanisms preserve muscular function for several months and then are overwhelmed. Deterioration of mouse phenotype after ChAT gene disruption is a specific aging process reminiscent of human pathological situations, particularly among survivors of paralytic poliomyelitis. These mutant mice may represent an invaluable tool to determine the sequence of events that follow the loss of function of a motor neuron subset as the disease progresses, and to evaluate therapeutic strategies. They also offer the opportunity to explore fundamental issues of motor neuron biology.
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Affiliation(s)
- Marie-José Lecomte
- CRICM, CNRS UMR 7225, Paris, France; UPMC Univ Paris 06, UMR 7225, Paris, France; Inserm, UMR_S975, Paris, France
| | - Chloé Bertolus
- CRICM, CNRS UMR 7225, Paris, France; UPMC Univ Paris 06, UMR 7225, Paris, France; Inserm, UMR_S975, Paris, France; AP-HP, Hôpital Pitié-Salpêtrière, Département de Chirurgie Maxillo-Faciale, Paris, France
| | - Julie Santamaria
- CRICM, CNRS UMR 7225, Paris, France; UPMC Univ Paris 06, UMR 7225, Paris, France; Inserm, UMR_S975, Paris, France
| | - Anne-Laure Bauchet
- Molecular Imaging Research Center (MIRCen), CEA, 92265 Fontenay-aux-Roses, France
| | - Marc Herbin
- UMR 7179, CNRS and Muséum National d'Histoire Naturelle, Paris, France
| | - Françoise Saurini
- CRICM, CNRS UMR 7225, Paris, France; UPMC Univ Paris 06, UMR 7225, Paris, France; Inserm, UMR_S975, Paris, France
| | - Hidemi Misawa
- Department of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
| | - Thierry Maisonobe
- AP-HP, Hôpital Pitié-Salpêtrière, Département de Neurophysiologie Clinique, Paris, France
| | - Pierre-François Pradat
- AP-HP, Hôpital Pitié-Salpêtrière, Département des Maladies du Système Nerveux, Paris, France; UMR-678, Inserm-UPMC, Hôpital Pitié-Salpêtrière, Paris, France
| | | | - Jacques Mallet
- CRICM, CNRS UMR 7225, Paris, France; UPMC Univ Paris 06, UMR 7225, Paris, France; Inserm, UMR_S975, Paris, France
| | - Sylvie Berrard
- CRICM, CNRS UMR 7225, Paris, France; UPMC Univ Paris 06, UMR 7225, Paris, France; Inserm, UMR_S975, Paris, France.
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Steyn FJ, Lee K, Fogarty MJ, Veldhuis JD, McCombe PA, Bellingham MC, Ngo ST, Chen C. Growth hormone secretion is correlated with neuromuscular innervation rather than motor neuron number in early-symptomatic male amyotrophic lateral sclerosis mice. Endocrinology 2013; 154:4695-706. [PMID: 24108071 DOI: 10.1210/en.2013-1570] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
GH deficiency is thought to be involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). However, therapy with GH and/or IGF-I has not shown benefit. To gain a better understanding of the role of GH secretion in ALS pathogenesis, we assessed endogenous GH secretion in wild-type and hSOD1(G93A) mice throughout the course of ALS disease. Male wild-type and hSOD1(G93A) mice were studied at the presymptomatic, onset, and end stages of disease. To assess the pathological features of disease, we measured motor neuron number and neuromuscular innervation. We report that GH secretion profile varies at different stages of disease progression in hSOD1(G93A) mice; compared with age-matched controls, GH secretion is unchanged prior to the onset of disease symptoms, elevated at the onset of disease symptoms, and reduced at the end stage of disease. In hSOD1(G93A) mice at the onset of disease, GH secretion is positively correlated with the percentage of neuromuscular innervation but not with motor neuron number. Moreover, this occurs in parallel with an elevation in the expression of muscle IGF-I relative to controls. Our data imply that increased GH secretion at symptom onset may be an endogenous endocrine response to increase the local production of muscle IGF-I to stimulate reinnervation of muscle, but that in the latter stages of disease this response no longer occurs.
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Affiliation(s)
- F J Steyn
- School of Biomedical Sciences, University of Queensland, St Lucia 4072, Australia. ; or Prof Chen Chen, School of Biomedical Sciences, University of Queensland, St Lucia 4072, Australia. E-mail:
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Bruneteau G, Simonet T, Bauché S, Mandjee N, Malfatti E, Girard E, Tanguy ML, Behin A, Khiami F, Sariali E, Hell-Remy C, Salachas F, Pradat PF, Fournier E, Lacomblez L, Koenig J, Romero NB, Fontaine B, Meininger V, Schaeffer L, Hantaï D. Muscle histone deacetylase 4 upregulation in amyotrophic lateral sclerosis: potential role in reinnervation ability and disease progression. ACTA ACUST UNITED AC 2013; 136:2359-68. [PMID: 23824486 DOI: 10.1093/brain/awt164] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis is a typically rapidly progressive neurodegenerative disorder affecting motor neurons leading to progressive muscle paralysis and death, usually from respiratory failure, in 3-5 years. Some patients have slow disease progression and prolonged survival, but the underlying mechanisms remain poorly understood. Riluzole, the only approved treatment, only modestly prolongs survival and has no effect on muscle function. In the early phase of the disease, motor neuron loss is initially compensated for by collateral reinnervation, but over time this compensation fails, leading to progressive muscle wasting. The crucial role of muscle histone deacetylase 4 and its regulator microRNA-206 in compensatory reinnervation and disease progression was recently suggested in a mouse model of amyotrophic lateral sclerosis (transgenic mice carrying human mutations in the superoxide dismutase gene). Here, we sought to investigate whether the microRNA-206-histone deacetylase 4 pathway plays a role in muscle compensatory reinnervation in patients with amyotrophic lateral sclerosis and thus contributes to disease outcome differences. We studied muscle reinnervation using high-resolution confocal imaging of neuromuscular junctions in muscle samples obtained from 11 patients with amyotrophic lateral sclerosis, including five long-term survivors. We showed that the proportion of reinnervated neuromuscular junctions was significantly higher in long-term survivors than in patients with rapidly progressive disease. We analysed the expression of muscle candidate genes involved in the reinnervation process and showed that histone deacetylase 4 upregulation was significantly greater in patients with rapidly progressive disease and was negatively correlated with the extent of muscle reinnervation and functional outcome. Conversely, the proposed regulator of histone deacetylase 4, microRNA-206, was upregulated in both patient groups, but did not correlate with disease progression or reinnervation. We conclude that muscle expression of histone deacetylase 4 may be a key factor for muscle reinnervation and disease progression in patients with amyotrophic lateral sclerosis. Specific histone deacetylase 4 inhibitors may then constitute a therapeutic approach to enhancing motor performance and slowing disease progression in amyotrophic lateral sclerosis.
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Affiliation(s)
- Gaëlle Bruneteau
- APHP, Hôpital Pitié-Salpêtrière, Département de Neurologie, Centre référent SLA, Paris Cedex 13, France.
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Armstrong GAB, Drapeau P. Loss and gain of FUS function impair neuromuscular synaptic transmission in a genetic model of ALS. Hum Mol Genet 2013; 22:4282-92. [PMID: 23771027 DOI: 10.1093/hmg/ddt278] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) presents clinically in adulthood and is characterized by the loss of motoneurons in the spinal cord and cerebral cortex. Animal models of the disease suggest that significant neuronal abnormalities exist during preclinical stages of the disease. Mutations in the gene fused in sarcoma (FUS) are associated with ALS and cause impairment in motor function in animal models. However, the mechanism of neuromuscular dysfunction underlying pathophysiological deficits causing impairment in locomotor function resulting from mutant FUS expression is unknown. To characterize the cellular pathophysiological defect, we expressed the wild-type human gene (wtFUS) or the ALS-associated mutation R521H (mutFUS) gene in zebrafish larvae and characterized their motor (swimming) activity and function of their neuromuscular junctions (NMJs). Additionally, we tested knockdown of zebrafish fus with an antisense morpholino oligonucleotide (fus AMO). Expression of either mutFUS or knockdown of fus resulted in impaired motor activity and reduced NMJ synaptic fidelity with reduced quantal transmission. Primary motoneurons expressing mutFUS were found to be more excitable. These impairments in neuronal function could be partially restored in fus AMO larvae also expressing wtFUS (fus AMO+wtFUS) but not mutFUS (fus AMO+mutFUS). These results show that both a loss and gain of FUS function result in defective presynaptic function at the NMJ.
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Affiliation(s)
- Gary A B Armstrong
- Department of Pathology and Cell Biology and Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC, Canada H3C 3J7
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Calcium channel agonists protect against neuromuscular dysfunction in a genetic model of TDP-43 mutation in ALS. J Neurosci 2013; 33:1741-52. [PMID: 23345247 DOI: 10.1523/jneurosci.4003-12.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TAR DNA binding protein (TDP-43, encoded by the TARDBP gene) has recently been shown to be associated with amyotrophic lateral sclerosis (ALS), but the early pathophysiological deficits causing impairment in motor function are unknown. Here we expressed the wild-type human gene (wtTARDBP) or the ALS mutation G348C (mutTARDBP) in zebrafish larvae and characterized their motor (swimming) activity and the structure and function of their neuromuscular junctions (NMJs). Of these groups only mutTARDBP larvae showed impaired swimming and increased motoneuron vulnerability with reduced synaptic fidelity, reduced quantal transmission, and more orphaned presynaptic and postsynaptic structures at the NMJ. Remarkably, all behavioral and cellular features were stabilized by chronic treatment with either of the L-type calcium channel agonists FPL 64176 or Bay K 8644. These results indicate that expression of mutTARDBP results in defective NMJs and that calcium channel agonists could be novel therapeutics for ALS.
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Steyn FJ, Ngo ST, Lee JD, Leong JW, Buckley AJ, Veldhuis JD, McCombe PA, Chen C, Bellingham MC. Impairments to the GH-IGF-I axis in hSOD1G93A mice give insight into possible mechanisms of GH dysregulation in patients with amyotrophic lateral sclerosis. Endocrinology 2012; 153:3735-46. [PMID: 22621959 DOI: 10.1210/en.2011-2171] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GH deficiency has been found in subjects with amyotrophic lateral sclerosis (ALS). Disrupted endocrine function could contribute to the progressive muscle loss and hypermetabolism seen in ALS. It is not possible to study all the elements of the GH-IGF-I axis in ALS patients. Consequently, it remains unclear whether dysfunctional GH secretion contributes to disease pathogenesis and why GH and IGF-I directed treatment strategies are ineffective in human ALS. The hSOD1(G93A) transgenic mouse model is useful for the detailed investigation of the pathogenesis of ALS. We report that symptomatic male hSOD1(G93A) transgenic mice exhibit a deficiency in GH secretion similar to that seen in human ALS. Further characterization of the GH-IGF-I axis in hSOD1(G93A) mice reveals central and peripheral abnormalities that are not found in wild-type age-matched controls. Specifically, we observe aberrant endogenous pulsatile GH secretion, reduced pituitary GH content, and decreased circulating levels of IGF-I, indicating global GH deficiency in hSOD1(G93A) mice. Furthermore, a reduction in the expression of the IGF-I receptor α-subunit in skeletal muscle and lumbar spinal cords of hSOD1(G93A) mice suggests impaired IGF-I signaling within these tissues. This is the first account of disrupted GH secretion in a transgenic mouse model of ALS. These observations are essential for the development of effective GH and IGF-I targeted therapies in ALS.
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Affiliation(s)
- F J Steyn
- School of Biomedical Sciences, University of Queensland, St. Lucia 4072, Australia.
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Nguyen KT, Zhang Z, Barrett EF, David G. Morphological and functional changes in innervation of a fast forelimb muscle in SOD1-G85R mice. Neurobiol Dis 2012; 48:399-408. [PMID: 22813866 DOI: 10.1016/j.nbd.2012.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/15/2012] [Accepted: 07/09/2012] [Indexed: 01/05/2023] Open
Abstract
Muscle endplates become denervated in mice that express mutations of human superoxide dismutase 1 (hSOD1), models of familial amyotrophic lateral sclerosis. This denervation is especially marked in fast limb muscles, and precedes death of motor neuron somata. This study used mice that expressed yellow fluorescent protein (YFP) in neurons to investigate changes in the morphology and function of axons and motor terminals innervating a fast forelimb muscle (epitrochleoanconeus, ETA) in presymptomatic and symptomatic hSOD1-G85R mice, compared to those in mice that express wild-type (wt) hSOD1. The percentage of endplates (identified using fluorescently-labeled α-bungarotoxin) innervated by motor terminals remained high in presymptomatic SOD1-G85R mice, but fell to ~50% in symptomatic mice. The number of large diameter (≥4 μm) axons in the ETA nerve also decreased as mice became symptomatic, and endplate innervation correlated best with the number of large diameter axons. Motor terminal function was assessed using changes in terminal YFP fluorescence evoked by trains of action potentials; different components of the pH-dependent YFP signals reflect stimulation-induced Ca2+ entry and vesicular exo/endocytosis. Most visible motor terminals (>90%) remained capable of responding to nerve stimulation in both pre- and symptomatic hSOD1-G85R mice, but with functional alterations. Responses in presymptomatic terminals suggested reduced acidification and increased vesicular release, whereas symptomatic terminals exhibited increased acidification and reduced vesicular release. The fact that most remaining terminals were able to respond to nerve stimulation suggests that motor terminal-protective therapies might contribute to preserving neuromuscular function in fALS mice.
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Affiliation(s)
- Khanh T Nguyen
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, P.O. Box 016430, Miami, FL 33101, USA
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Kalmar B, Edet-Amana E, Greensmith L. Treatment with a coinducer of the heat shock response delays muscle denervation in the SOD1-G93A mouse model of amyotrophic lateral sclerosis. ACTA ACUST UNITED AC 2012; 13:378-92. [DOI: 10.3109/17482968.2012.660953] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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