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Tadenev ALD, Hatton CL, Burgess RW. Lack of effect from genetic deletion of Hdac6 in a humanized mouse model of CMT2D. J Peripher Nerv Syst 2024; 29:213-220. [PMID: 38551018 PMCID: PMC11209801 DOI: 10.1111/jns.12623] [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: 02/11/2024] [Revised: 03/11/2024] [Accepted: 03/18/2024] [Indexed: 06/27/2024]
Abstract
BACKGROUND Inhibition of HDAC6 has been proposed as a broadly applicable therapeutic strategy for Charcot-Marie-Tooth disease (CMT). Inhibition of HDAC6 increases the acetylation of proteins important in axonal trafficking, such as α-tubulin and Miro, and has been shown to be efficacious in several preclinical studies using mouse models of CMT. AIMS Here, we sought to expand on previous preclinical studies by testing the effect of genetic deletion of Hdac6 on mice carrying a humanized knockin allele of Gars1, a model of CMT-type 2D. METHODS Gars1ΔETAQ mice were bred to an Hdac6 knockout strain, and the resulting offspring were evaluated for clinically relevant outcomes. RESULTS The genetic deletion of Hdac6 increased α-tubulin acetylation in the sciatic nerves of both wild-type and Gars1ΔETAQ mice. However, when tested at 5 weeks of age, the Gars1ΔETAQ mice lacking Hdac6 showed no changes in body weight, muscle atrophy, grip strength or endurance, sciatic motor nerve conduction velocity, compound muscle action potential amplitude, or peripheral nerve histopathology compared to Gars1ΔETAQ mice with intact Hdac6. INTERPRETATION Our results differ from those of two previous studies that demonstrated the benefit of the HDAC6 inhibitor tubastatin A in mouse models of CMT2D. While we cannot fully explain the different outcomes, our results offer a counterexample to the benefit of inhibiting HDAC6 in CMT2D, suggesting additional research is necessary.
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Rhymes ER, Simkin RL, Qu J, Villarroel-Campos D, Surana S, Tong Y, Shapiro R, Burgess RW, Yang XL, Schiavo G, Sleigh JN. Boosting BDNF in muscle rescues impaired axonal transport in a mouse model of DI-CMTC peripheral neuropathy. Neurobiol Dis 2024; 195:106501. [PMID: 38583640 DOI: 10.1016/j.nbd.2024.106501] [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: 03/12/2024] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a genetic peripheral neuropathy caused by mutations in many functionally diverse genes. The aminoacyl-tRNA synthetase (ARS) enzymes, which transfer amino acids to partner tRNAs for protein synthesis, represent the largest protein family genetically linked to CMT aetiology, suggesting pathomechanistic commonalities. Dominant intermediate CMT type C (DI-CMTC) is caused by YARS1 mutations driving a toxic gain-of-function in the encoded tyrosyl-tRNA synthetase (TyrRS), which is mediated by exposure of consensus neomorphic surfaces through conformational changes of the mutant protein. In this study, we first showed that human DI-CMTC-causing TyrRSE196K mis-interacts with the extracellular domain of the BDNF receptor TrkB, an aberrant association we have previously characterised for several mutant glycyl-tRNA synthetases linked to CMT type 2D (CMT2D). We then performed temporal neuromuscular assessments of YarsE196K mice modelling DI-CMT. We determined that YarsE196K homozygotes display a selective, age-dependent impairment in in vivo axonal transport of neurotrophin-containing signalling endosomes, phenocopying CMT2D mice. This impairment is replicated by injection of recombinant TyrRSE196K, but not TyrRSWT, into muscles of wild-type mice. Augmenting BDNF in DI-CMTC muscles, through injection of recombinant protein or muscle-specific gene therapy, resulted in complete axonal transport correction. Therefore, this work identifies a non-cell autonomous pathomechanism common to ARS-related neuropathies, and highlights the potential of boosting BDNF levels in muscles as a therapeutic strategy.
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Affiliation(s)
- Elena R Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Rebecca L Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Ji Qu
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ryan Shapiro
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK.
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3
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Rhymes ER, Simkin RL, Qu J, Villarroel-Campos D, Surana S, Tong Y, Shapiro R, Burgess RW, Yang XL, Schiavo G, Sleigh JN. Boosting BDNF in muscle rescues impaired axonal transport in a mouse model of DI-CMTC peripheral neuropathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.09.536152. [PMID: 38559020 PMCID: PMC10979848 DOI: 10.1101/2023.04.09.536152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Charcot-Marie-Tooth disease (CMT) is a genetic peripheral neuropathy caused by mutations in many functionally diverse genes. The aminoacyl-tRNA synthetase (ARS) enzymes, which transfer amino acids to partner tRNAs for protein synthesis, represent the largest protein family genetically linked to CMT aetiology, suggesting pathomechanistic commonalities. Dominant intermediate CMT type C (DI-CMTC) is caused by YARS1 mutations driving a toxic gain-of-function in the encoded tyrosyl-tRNA synthetase (TyrRS), which is mediated by exposure of consensus neomorphic surfaces through conformational changes of the mutant protein. In this study, we first showed that human DI-CMTC-causing TyrRSE196K mis-interacts with the extracellular domain of the BDNF receptor TrkB, an aberrant association we have previously characterised for several mutant glycyl-tRNA synthetases linked to CMT type 2D (CMT2D). We then performed temporal neuromuscular assessments of YarsE196K mice modelling DI-CMT. We determined that YarsE196K homozygotes display a selective, age-dependent impairment in in vivo axonal transport of neurotrophin-containing signalling endosomes, phenocopying CMT2D mice. This impairment is replicated by injection of recombinant TyrRSE196K, but not TyrRSWT, into muscles of wild-type mice. Augmenting BDNF in DI-CMTC muscles, through injection of recombinant protein or muscle-specific gene therapy, resulted in complete axonal transport correction. Therefore, this work identifies a non-cell autonomous pathomechanism common to ARS-related neuropathies, and highlights the potential of boosting BDNF levels in muscles as a therapeutic strategy.
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Affiliation(s)
- Elena R. Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Rebecca L. Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Ji Qu
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ryan Shapiro
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - James N. Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
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4
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Hines TJ, Bailey J, Liu H, Guntur AR, Seburn KL, Pratt SL, Funke JR, Tarantino LM, Burgess RW. A Novel ENU-Induced Mfn2 Mutation Causes Motor Deficits in Mice without Causing Peripheral Neuropathy. BIOLOGY 2023; 12:953. [PMID: 37508383 PMCID: PMC10376023 DOI: 10.3390/biology12070953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023]
Abstract
Mitochondrial fission and fusion are required for maintaining functional mitochondria. The mitofusins (MFN1 and MFN2) are known for their roles in mediating mitochondrial fusion. Recently, MFN2 has been implicated in other important cellular functions, such as mitophagy, mitochondrial motility, and coordinating endoplasmic reticulum-mitochondria communication. In humans, over 100 MFN2 mutations are associated with a form of inherited peripheral neuropathy, Charcot-Marie-Tooth disease type 2A (CMT2A). Here we describe an ENU-induced mutant mouse line with a recessive neuromuscular phenotype. Behavioral screening showed progressive weight loss and rapid deterioration of motor function beginning at 8 weeks. Mapping and sequencing revealed a missense mutation in exon 18 of Mfn2 (T1928C; Leu643Pro), within the transmembrane domain. Compared to wild-type and heterozygous littermates, Mfn2L643P/L643P mice exhibited diminished rotarod performance and decreases in activity in the open field test, muscular endurance, mean mitochondrial diameter, sensory tests, mitochondrial DNA content, and MFN2 protein levels. However, tests of peripheral nerve physiology and histology were largely normal. Mutant leg bones had reduced cortical bone thickness and bone area fraction. Together, our data indicate that Mfn2L643P causes a recessive motor phenotype with mild bone and mitochondrial defects in mice. Lack of apparent nerve pathology notwithstanding, this is the first reported mouse model with a mutation in the transmembrane domain of the protein, which may be valuable for researchers studying MFN2 biology.
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Affiliation(s)
| | - Janice Bailey
- Department of Genetics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hedi Liu
- Department of Genetics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Anyonya R Guntur
- Center for Molecular Medicine, Maine Health Institute for Research, Scarborough, ME 04074, USA
| | | | - Samia L Pratt
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Jonathan R Funke
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Lisa M Tarantino
- Department of Genetics, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
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5
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Kalotay E, Klugmann M, Housley GD, Fröhlich D. Dominant aminoacyl-tRNA synthetase disorders: lessons learned from in vivo disease models. Front Neurosci 2023; 17:1182845. [PMID: 37274211 PMCID: PMC10234151 DOI: 10.3389/fnins.2023.1182845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 04/05/2023] [Indexed: 06/06/2023] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) play an essential role in protein synthesis, being responsible for ligating tRNA molecules to their corresponding amino acids in a reaction known as 'tRNA aminoacylation'. Separate ARSs carry out the aminoacylation reaction in the cytosol and in mitochondria, and mutations in almost all ARS genes cause pathophysiology most evident in the nervous system. Dominant mutations in multiple cytosolic ARSs have been linked to forms of peripheral neuropathy including Charcot-Marie-Tooth disease, distal hereditary motor neuropathy, and spinal muscular atrophy. This review provides an overview of approaches that have been employed to model each of these diseases in vivo, followed by a discussion of the existing animal models of dominant ARS disorders and key mechanistic insights that they have provided. In summary, ARS disease models have demonstrated that loss of canonical ARS function alone cannot fully account for the observed disease phenotypes, and that pathogenic ARS variants cause developmental defects within the peripheral nervous system, despite a typically later onset of disease in humans. In addition, aberrant interactions between mutant ARSs and other proteins have been shown to contribute to the disease phenotypes. These findings provide a strong foundation for future research into this group of diseases, providing methodological guidance for studies on ARS disorders that currently lack in vivo models, as well as identifying candidate therapeutic targets.
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Affiliation(s)
- Elizabeth Kalotay
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Gary D. Housley
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Dominik Fröhlich
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
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O'Connor K, Spendiff S, Lochmüller H, Horvath R. Mitochondrial Mutations Can Alter Neuromuscular Transmission in Congenital Myasthenic Syndrome and Mitochondrial Disease. Int J Mol Sci 2023; 24:ijms24108505. [PMID: 37239850 DOI: 10.3390/ijms24108505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are a group of rare, neuromuscular disorders that usually present in childhood or infancy. While the phenotypic presentation of these disorders is diverse, the unifying feature is a pathomechanism that disrupts neuromuscular transmission. Recently, two mitochondrial genes-SLC25A1 and TEFM-have been reported in patients with suspected CMS, prompting a discussion about the role of mitochondria at the neuromuscular junction (NMJ). Mitochondrial disease and CMS can present with similar symptoms, and potentially one in four patients with mitochondrial myopathy exhibit NMJ defects. This review highlights research indicating the prominent roles of mitochondria at both the pre- and postsynapse, demonstrating the potential for mitochondrial involvement in neuromuscular transmission defects. We propose the establishment of a novel subcategorization for CMS-mitochondrial CMS, due to unifying clinical features and the potential for mitochondrial defects to impede transmission at the pre- and postsynapse. Finally, we highlight the potential of targeting the neuromuscular transmission in mitochondrial disease to improve patient outcomes.
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Affiliation(s)
- Kaela O'Connor
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H 8M5, Canada
| | - Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, 79104 Freiburg, Germany
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Catalonia, Spain
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB3 0FD, UK
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7
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Sleigh JN, Villarroel-Campos D, Surana S, Wickenden T, Tong Y, Simkin RL, Vargas JNS, Rhymes ER, Tosolini AP, West SJ, Zhang Q, Yang XL, Schiavo G. Boosting peripheral BDNF rescues impaired in vivo axonal transport in CMT2D mice. JCI Insight 2023; 8:e157191. [PMID: 36928301 PMCID: PMC10243821 DOI: 10.1172/jci.insight.157191] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
Gain-of-function mutations in the housekeeping gene GARS1, which lead to the expression of toxic versions of glycyl-tRNA synthetase (GlyRS), cause the selective motor and sensory pathology characterizing Charcot-Marie-Tooth disease (CMT). Aberrant interactions between GlyRS mutants and different proteins, including neurotrophin receptor tropomyosin receptor kinase receptor B (TrkB), underlie CMT type 2D (CMT2D); however, our pathomechanistic understanding of this untreatable peripheral neuropathy remains incomplete. Through intravital imaging of the sciatic nerve, we show that CMT2D mice displayed early and persistent disturbances in axonal transport of neurotrophin-containing signaling endosomes in vivo. We discovered that brain-derived neurotrophic factor (BDNF)/TrkB impairments correlated with transport disruption and overall CMT2D neuropathology and that inhibition of this pathway at the nerve-muscle interface perturbed endosome transport in wild-type axons. Accordingly, supplementation of muscles with BDNF, but not other neurotrophins, completely restored physiological axonal transport in neuropathic mice. Together, these findings suggest that selectively targeting muscles with BDNF-boosting therapies could represent a viable therapeutic strategy for CMT2D.
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Affiliation(s)
- James N. Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
| | - Tahmina Wickenden
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Rebecca L. Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Jose Norberto S. Vargas
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Elena R. Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Andrew P. Tosolini
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | | | - Qian Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
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Ermanoska B, Asselbergh B, Morant L, Petrovic-Erfurth ML, Hosseinibarkooie S, Leitão-Gonçalves R, Almeida-Souza L, Bervoets S, Sun L, Lee L, Atkinson D, Khanghahi A, Tournev I, Callaerts P, Verstreken P, Yang XL, Wirth B, Rodal AA, Timmerman V, Goode BL, Godenschwege TA, Jordanova A. Tyrosyl-tRNA synthetase has a noncanonical function in actin bundling. Nat Commun 2023; 14:999. [PMID: 36890170 PMCID: PMC9995517 DOI: 10.1038/s41467-023-35908-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 01/06/2023] [Indexed: 03/10/2023] Open
Abstract
Dominant mutations in tyrosyl-tRNA synthetase (YARS1) and six other tRNA ligases cause Charcot-Marie-Tooth peripheral neuropathy (CMT). Loss of aminoacylation is not required for their pathogenicity, suggesting a gain-of-function disease mechanism. By an unbiased genetic screen in Drosophila, we link YARS1 dysfunction to actin cytoskeleton organization. Biochemical studies uncover yet unknown actin-bundling property of YARS1 to be enhanced by a CMT mutation, leading to actin disorganization in the Drosophila nervous system, human SH-SY5Y neuroblastoma cells, and patient-derived fibroblasts. Genetic modulation of F-actin organization improves hallmark electrophysiological and morphological features in neurons of flies expressing CMT-causing YARS1 mutations. Similar beneficial effects are observed in flies expressing a neuropathy-causing glycyl-tRNA synthetase. Hence, in this work, we show that YARS1 is an evolutionary-conserved F-actin organizer which links the actin cytoskeleton to tRNA-synthetase-induced neurodegeneration.
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Affiliation(s)
- Biljana Ermanoska
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biology, Brandeis University, Waltham, MA, 02453, USA
| | - Bob Asselbergh
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, 2610, Antwerp, Belgium
- Neuromics Support Facility, Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Laura Morant
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
| | - Maria-Luise Petrovic-Erfurth
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics; Center for Molecular Medicine Cologne; Center for Rare Diseases Cologne, University Hospital of Cologne; University of Cologne, 50931, Cologne, Germany
- Division of Endocrinology and Metabolism and Department of Neuroscience, University of Virginia, Charlottesville, VA, USA
| | - Ricardo Leitão-Gonçalves
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
- Frontiers Media SA, Lausanne, Switzerland
| | - Leonardo Almeida-Souza
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
- Helsinki Institute of Life Science, Institute of Biotechnology & Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Sven Bervoets
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Neurobiology, University of Utah, Salt Lake City, UT, USA
| | - Litao Sun
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- School of Public Health (Shenzhen), Sun Yat-Sen University, Guangdong, China
| | - LaTasha Lee
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, 33458, USA
- Center for Social and Clinical Research, National Minority Quality Forum, Washington, DC, USA
| | - Derek Atkinson
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Akram Khanghahi
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
| | - Ivaylo Tournev
- Department of Neurology, Medical University-Sofia, 1431, Sofia, Bulgaria
- Department of Cognitive Science and Psychology, New Bulgarian University, 1618, Sofia, Bulgaria
| | | | - Patrik Verstreken
- VIB-KU Leuven Center for Brain & Disease Research, 3000, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Mission Lucidity, 3000, Leuven, Belgium
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Brunhilde Wirth
- Institute of Human Genetics; Center for Molecular Medicine Cologne; Center for Rare Diseases Cologne, University Hospital of Cologne; University of Cologne, 50931, Cologne, Germany
| | - Avital A Rodal
- Department of Biology, Brandeis University, Waltham, MA, 02453, USA
| | - Vincent Timmerman
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA, 02453, USA
| | - Tanja A Godenschwege
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Albena Jordanova
- Center for Molecular Neurology, VIB, University of Antwerp, 2610, Antwerpen, Belgium.
- Department of Biomedical Sciences, University of Antwerp, 2610, Antwerpen, Belgium.
- Department of Medical Chemistry and Biochemistry, Medical University-Sofia, 1431, Sofia, Bulgaria.
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9
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McMacken G, Whittaker RG, Wake R, Lochmuller H, Horvath R. Neuromuscular junction involvement in inherited motor neuropathies: genetic heterogeneity and effect of oral salbutamol treatment. J Neurol 2023; 270:3112-3119. [PMID: 36869887 DOI: 10.1007/s00415-023-11643-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/01/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023]
Abstract
OBJECTIVES Inherited defects of the neuromuscular junction (NMJ) comprise an increasingly diverse range of diseases. Several recently identified genes highlight the overlap between peripheral neuropathies and congenital myasthenic syndromes (CMS). The beta-2 adrenergic receptor agonist salbutamol has been shown to provide symptomatic benefit in CMS, while improving structural defects at the NMJ. Based on these findings, we identified cases of motor neuropathy with NMJ dysfunction and assessed the effect of salbutamol on motor function. METHODS Cases of motor neuropathy with significant NMJ dysfunction, were identified using repetitive nerve stimulation and single fibre electromyography. Oral salbutamol was administered for 12 months. Repeat neurophysiological and clinical assessments were undertaken at baseline, 6 months and 12 months. RESULTS Significant defects of neuromuscular transmission were identified in 15 patients harbouring a range of genetic defects, including mutations in GARS1, DNM2, SYT2 and DYNC1H. No clear benefit on motor function was seen following the administration of 12 months of oral salbutamol; however, there was a significant improvement in patient reported fatigue. In addition, no clear effect on neurophysiological parameters was seen in patients treated with salbutamol. Side-effects due to off-target beta-adrenergic effects were significant in the patient cohort. CONCLUSION These results highlight the involvement of the NMJ in several subtypes of motor neuropathies, including subtypes of neuropathy due to deficits in mitochondrial fusion-fission, synaptic vesicle transport, calcium channels and tRNA synthetases. Whether the NMJ dysfunction is simply due to muscle reinnervation or a pathology unrelated to denervation is unknown. The involvement of the NMJ may represent a novel therapeutic target in these conditions. However, treatment regimens will need to be more targeted for patients with primary inherited defects of neuromuscular transmission.
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Affiliation(s)
- Grace McMacken
- Department of Neurology, Royal Victoria Hospital, Belfast Health and Social Care Trust, Belfast, UK
| | - Roger G Whittaker
- Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Ruth Wake
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | - Hanns Lochmuller
- Division of Neurology, Department of Medicine, Children's Hospital of Eastern Ontario Research Institute, The Ottawa Hospital and Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada
| | - Rita Horvath
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge School of Clinical Medicine, Level 3 A Block, Box 165, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
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10
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Beloribi-Djefaflia S, Attarian S. Treatment of Charcot-Marie-Tooth neuropathies. Rev Neurol (Paris) 2023; 179:35-48. [PMID: 36588067 DOI: 10.1016/j.neurol.2022.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/18/2022] [Accepted: 11/24/2022] [Indexed: 12/31/2022]
Abstract
Charcot-Marie-Tooth (CMT) is a heterogeneous group of inherited neuropathies that affect the peripheral nerves and slowly cause progressive disability. Currently, there is no effective therapy. Patients' management is based on rehabilitation and occupational therapy, fatigue, and pain treatment with regular follow-up according to the severity of the disease. In the last three decades, much progress has been made to identify mutations involved in the different types of CMT, decipher the pathophysiology of the disease, and identify key genes and pathways that could be targeted to propose new therapeutic strategies. Genetic therapy is one of the fields of interest to silence genes such as PMP22 in CMT1A or to express GJB1 in CMT1X. Among the most promising molecules, inhibitors of the NRG-1 axis and modulators of UPR or the HDACs enzyme family could be used in different types of CMT.
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Affiliation(s)
- S Beloribi-Djefaflia
- Reference center for neuromuscular disorders and ALS, AP-HM, CHU La Timone, Marseille, France
| | - S Attarian
- Reference center for neuromuscular disorders and ALS, AP-HM, CHU La Timone, Marseille, France; FILNEMUS, European Reference Network for Rare Diseases (ERN), Marseille, France; Medical Genetics, Aix Marseille Université-Inserm UMR_1251, 13005 Marseille, France.
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11
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Sato-Yamada Y, Strickland A, Sasaki Y, Bloom J, DiAntonio A, Milbrandt J. A SARM1-mitochondrial feedback loop drives neuropathogenesis in a Charcot-Marie-Tooth disease type 2A rat model. J Clin Invest 2022; 132:e161566. [PMID: 36287202 PMCID: PMC9711878 DOI: 10.1172/jci161566] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 10/11/2022] [Indexed: 11/17/2022] Open
Abstract
Charcot-Marie-Tooth disease type 2A (CMT2A) is an axonal neuropathy caused by mutations in the mitofusin 2 (MFN2) gene. MFN2 mutations result in profound mitochondrial abnormalities, but the mechanism underlying the axonal pathology is unknown. Sterile α and Toll/IL-1 receptor motif-containing 1 (SARM1), the central executioner of axon degeneration, can induce neuropathy and is activated by dysfunctional mitochondria. We tested the role of SARM1 in a rat model carrying a dominant CMT2A mutation (Mfn2H361Y) that exhibits progressive dying-back axonal degeneration, neuromuscular junction (NMJ) abnormalities, muscle atrophy, and mitochondrial abnormalities - all hallmarks of the human disease. We generated Sarm1-KO (Sarm1-/-) and Mfn2H361Y Sarm1 double-mutant rats and found that deletion of Sarm1 rescued axonal, synaptic, muscle, and functional phenotypes, demonstrating that SARM1 was responsible for much of the neuropathology in this model. Despite the presence of mutant MFN2 protein in these double-mutant rats, loss of SARM1 also dramatically suppressed many mitochondrial defects, including the number, size, and cristae density defects of synaptic mitochondria. This surprising finding indicates that dysfunctional mitochondria activated SARM1 and that activated SARM1 fed back on mitochondria to exacerbate the mitochondrial pathology. As such, this work identifies SARM1 inhibition as a therapeutic candidate for the treatment of CMT2A and other neurodegenerative diseases with prominent mitochondrial pathology.
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Affiliation(s)
- Yurie Sato-Yamada
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Science, Niigata City, Japan
| | - Amy Strickland
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yo Sasaki
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Joseph Bloom
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
- Needleman Center for Neurometabolism and Axonal Therapeutics, St. Louis, Missouri, USA
| | - Aaron DiAntonio
- Needleman Center for Neurometabolism and Axonal Therapeutics, St. Louis, Missouri, USA
- Department of Developmental Biology and
| | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
- Needleman Center for Neurometabolism and Axonal Therapeutics, St. Louis, Missouri, USA
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, Missouri, USA
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12
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Jennings MJ, Kagiava A, Vendredy L, Spaulding EL, Stavrou M, Hathazi D, Grüneboom A, De Winter V, Gess B, Schara U, Pogoryelova O, Lochmüller H, Borchers CH, Roos A, Burgess RW, Timmerman V, Kleopa KA, Horvath R. NCAM1 and GDF15 are biomarkers of Charcot-Marie-Tooth disease in patients and mice. Brain 2022; 145:3999-4015. [PMID: 35148379 PMCID: PMC9679171 DOI: 10.1093/brain/awac055] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/22/2021] [Accepted: 12/15/2021] [Indexed: 02/02/2023] Open
Abstract
Molecular markers scalable for clinical use are critical for the development of effective treatments and the design of clinical trials. Here, we identify proteins in sera of patients and mouse models with Charcot-Marie-Tooth disease (CMT) with characteristics that make them suitable as biomarkers in clinical practice and therapeutic trials. We collected serum from mouse models of CMT1A (C61 het), CMT2D (GarsC201R, GarsP278KY), CMT1X (Gjb1-null), CMT2L (Hspb8K141N) and from CMT patients with genotypes including CMT1A (PMP22d), CMT2D (GARS), CMT2N (AARS) and other rare genetic forms of CMT. The severity of neuropathy in the patients was assessed by the CMT Neuropathy Examination Score (CMTES). We performed multitargeted proteomics on both sample sets to identify proteins elevated across multiple mouse models and CMT patients. Selected proteins and additional potential biomarkers, such as growth differentiation factor 15 (GDF15) and cell free mitochondrial DNA, were validated by ELISA and quantitative PCR, respectively. We propose that neural cell adhesion molecule 1 (NCAM1) is a candidate biomarker for CMT, as it was elevated in Gjb1-null, Hspb8K141N, GarsC201R and GarsP278KY mice as well as in patients with both demyelinating (CMT1A) and axonal (CMT2D, CMT2N) forms of CMT. We show that NCAM1 may reflect disease severity, demonstrated by a progressive increase in mouse models with time and a significant positive correlation with CMTES neuropathy severity in patients. The increase in NCAM1 may reflect muscle regeneration triggered by denervation, which could potentially track disease progression or the effect of treatments. We found that member proteins of the complement system were elevated in Gjb1-null and Hspb8K141N mouse models as well as in patients with both demyelinating and axonal CMT, indicating possible complement activation at the impaired nerve terminals. However, complement proteins did not correlate with the severity of neuropathy measured on the CMTES scale. Although the complement system does not seem to be a prognostic biomarker, we do show complement elevation to be a common disease feature of CMT, which may be of interest as a therapeutic target. We also identify serum GDF15 as a highly sensitive diagnostic biomarker, which was elevated in all CMT genotypes as well as in Hspb8K141N, Gjb1-null, GarsC201R and GarsP278KY mouse models. Although we cannot fully explain its origin, it may reflect increased stress response or metabolic disturbances in CMT. Further large and longitudinal patient studies should be performed to establish the value of these proteins as diagnostic and prognostic molecular biomarkers for CMT.
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Affiliation(s)
- Matthew J Jennings
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Alexia Kagiava
- Department of Neuroscience and Neuromuscular Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Leen Vendredy
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, ME, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | - Marina Stavrou
- Department of Neuroscience and Neuromuscular Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Denisa Hathazi
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Anika Grüneboom
- Leibniz-Institut für Analytische Wissenschaften—ISAS—e.V, Dortmund, Germany
| | - Vicky De Winter
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Burkhard Gess
- Department of Neurology, University Hospital Aachen, Aachen, Germany
| | - Ulrike Schara
- Centre for Neuromuscular Disorders in Children, University of Duisburg-Essen, Essen, Germany
| | - Oksana Pogoryelova
- Directorate of Neurosciences, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals, NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Hanns Lochmüller
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Brain and Mind Research Institute and Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center–University of Freiburg, Faculty of Medicine, Freiburg, Germany
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
- Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Andreas Roos
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Brain and Mind Research Institute and Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
| | - Kleopas A Kleopa
- Department of Neuroscience and Neuromuscular Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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13
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McLean JW, Wilson JA, Tian T, Watson JA, VanHart M, Bean AJ, Scherer SS, Crossman DK, Ubogu E, Wilson SM. Disruption of Endosomal Sorting in Schwann Cells Leads to Defective Myelination and Endosomal Abnormalities Observed in Charcot-Marie-Tooth Disease. J Neurosci 2022; 42:5085-5101. [PMID: 35589390 PMCID: PMC9233440 DOI: 10.1523/jneurosci.2481-21.2022] [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: 12/16/2021] [Revised: 04/24/2022] [Accepted: 05/03/2022] [Indexed: 12/24/2022] Open
Abstract
Endosomal sorting plays a fundamental role in directing neural development. By altering the temporal and spatial distribution of membrane receptors, endosomes regulate signaling pathways that control the differentiation and function of neural cells. Several genes linked to inherited demyelinating peripheral neuropathies, known as Charcot-Marie-Tooth (CMT) disease, encode proteins that directly interact with components of the endosomal sorting complex required for transport (ESCRT). Our previous studies demonstrated that a point mutation in the ESCRT component hepatocyte growth-factor-regulated tyrosine kinase substrate (HGS), an endosomal scaffolding protein that identifies internalized cargo to be sorted by the endosome, causes a peripheral neuropathy in the neurodevelopmentally impaired teetering mice. Here, we constructed a Schwann cell-specific deletion of Hgs to determine the role of endosomal sorting during myelination. Inactivation of HGS in Schwann cells resulted in motor and sensory deficits, slowed nerve conduction velocities, delayed myelination and hypomyelinated axons, all of which occur in demyelinating forms of CMT. Consistent with a delay in Schwann cell maturation, HGS-deficient sciatic nerves displayed increased mRNA levels for several promyelinating genes and decreased mRNA levels for genes that serve as markers of myelinating Schwann cells. Loss of HGS also altered the abundance and activation of the ERBB2/3 receptors, which are essential for Schwann cell development. We therefore hypothesize that HGS plays a critical role in endosomal sorting of the ERBB2/3 receptors during Schwann cell maturation, which further implicates endosomal dysfunction in inherited peripheral neuropathies.SIGNIFICANCE STATEMENT Schwann cells myelinate peripheral axons, and defects in Schwann cell function cause inherited demyelinating peripheral neuropathies known as CMT. Although many CMT-linked mutations are in genes that encode putative endosomal proteins, little is known about the requirements of endosomal sorting during myelination. In this study, we demonstrate that loss of HGS disrupts the endosomal sorting pathway in Schwann cells, resulting in hypomyelination, aberrant myelin sheaths, and impairment of the ERBB2/3 receptor pathway. These findings suggest that defective endosomal trafficking of internalized cell surface receptors may be a common mechanism contributing to demyelinating CMT.
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Affiliation(s)
- John W McLean
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Julie A Wilson
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Tina Tian
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jennifer A Watson
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Mary VanHart
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Andrew J Bean
- Graduate College, Rush University, Chicago, Illinois 60612
| | - Steven S Scherer
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - David K Crossman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, 35294
| | - Eroboghene Ubogu
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
- Division of Neuromuscular Disease, Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Scott M Wilson
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294
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14
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Smith AS, Kim JH, Chun C, Gharai A, Moon HW, Kim EY, Nam SH, Ha N, Song JY, Chung KW, Doo HM, Hesson J, Mathieu J, Bothwell M, Choi BO, Kim DH. HDAC6 Inhibition Corrects Electrophysiological and Axonal Transport Deficits in a Human Stem Cell-Based Model of Charcot-Marie-Tooth Disease (Type 2D). Adv Biol (Weinh) 2022; 6:e2101308. [PMID: 34958183 PMCID: PMC8849597 DOI: 10.1002/adbi.202101308] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Indexed: 02/03/2023]
Abstract
Charcot-Marie-Tooth disease type 2D (CMT2D), is a hereditary peripheral neuropathy caused by mutations in the gene encoding glycyl-tRNA synthetase (GARS1). Here, human induced pluripotent stem cell (hiPSC)-based models of CMT2D bearing mutations in GARS1 and their use for the identification of predictive biomarkers amenable to therapeutic efficacy screening is described. Cultures containing spinal cord motor neurons generated from this line exhibit network activity marked by significant deficiencies in spontaneous action potential firing and burst fire behavior. This result matches clinical data collected from a patient bearing a GARS1P724H mutation and is coupled with significant decreases in acetylated α-tubulin levels and mitochondrial movement within axons. Treatment with histone deacetylase 6 inhibitors, tubastatin A and CKD504, improves mitochondrial movement and α-tubulin acetylation in these cells. Furthermore, CKD504 treatment enhances population-level electrophysiological activity, highlighting its potential as an effective treatment for CMT2D.
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Affiliation(s)
| | | | - Changho Chun
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Ava Gharai
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Hyo Won Moon
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Eun Young Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Soo Hyun Nam
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.,Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul 06351, Republic of Korea
| | - Nina Ha
- CKD Research Institute, Yongin, 16995, Republic of Korea
| | - Ju Yong Song
- CKD Research Institute, Yongin, 16995, Republic of Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju 32588, Republic of Korea
| | - Hyun Myung Doo
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Republic of Korea.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jennifer Hesson
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.,Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA
| | - Julie Mathieu
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.,Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA
| | - Mark Bothwell
- Department of Physiology and Biophysics, University of Washington, Seattle WA 98195, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Byung-Ok Choi
- Authors share corresponding authorship: To whom correspondence should be addressed: Dr. Deok-Ho Kim, Department of Biomedical Engineering, The Johns Hopkins University, Ross Research Building, 724B, 720 Rutland Avenue, Baltimore, MD 21205, , Dr. Byung-Ok Choi, Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Republic of Korea,
| | - Deok-Ho Kim
- Authors share corresponding authorship: To whom correspondence should be addressed: Dr. Deok-Ho Kim, Department of Biomedical Engineering, The Johns Hopkins University, Ross Research Building, 724B, 720 Rutland Avenue, Baltimore, MD 21205, , Dr. Byung-Ok Choi, Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Republic of Korea,
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15
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Hines TJ, Lutz C, Murray SA, Burgess RW. An Integrated Approach to Studying Rare Neuromuscular Diseases Using Animal and Human Cell-Based Models. Front Cell Dev Biol 2022; 9:801819. [PMID: 35047510 PMCID: PMC8762301 DOI: 10.3389/fcell.2021.801819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
As sequencing technology improves, the identification of new disease-associated genes and new alleles of known genes is rapidly increasing our understanding of the genetic underpinnings of rare diseases, including neuromuscular diseases. However, precisely because these disorders are rare and often heterogeneous, they are difficult to study in patient populations. In parallel, our ability to engineer the genomes of model organisms, such as mice or rats, has gotten increasingly efficient through techniques such as CRISPR/Cas9 genome editing, allowing the creation of precision human disease models. Such in vivo model systems provide an efficient means for exploring disease mechanisms and identifying therapeutic strategies. Furthermore, animal models provide a platform for preclinical studies to test the efficacy of those strategies. Determining whether the same mechanisms are involved in the human disease and confirming relevant parameters for treatment ideally involves a human experimental system. One system currently being used is induced pluripotent stem cells (iPSCs), which can then be differentiated into the relevant cell type(s) for in vitro confirmation of disease mechanisms and variables such as target engagement. Here we provide a demonstration of these approaches using the example of tRNA-synthetase-associated inherited peripheral neuropathies, rare forms of Charcot-Marie-Tooth disease (CMT). Mouse models have led to a better understanding of both the genetic and cellular mechanisms underlying the disease. To determine if the mechanisms are similar in human cells, we will use genetically engineered iPSC-based models. This will allow comparisons of different CMT-associated GARS alleles in the same genetic background, reducing the variability found between patient samples and simplifying the availability of cell-based models for a rare disease. The necessity of integrating mouse and human models, strategies for accomplishing this integration, and the challenges of doing it at scale are discussed using recently published work detailing the cellular mechanisms underlying GARS-associated CMT as a framework.
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16
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Ozes B, Moss K, Myers M, Ridgley A, Chen L, Murrey D, Sahenk Z. AAV1.NT-3 gene therapy in a CMT2D model: phenotypic improvements in GarsP278KY/+ mice. Brain Commun 2021; 3:fcab252. [PMID: 34755111 PMCID: PMC8568849 DOI: 10.1093/braincomms/fcab252] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 12/15/2022] Open
Abstract
Glycyl-tRNA synthetase mutations are associated to the Charcot-Marie-Tooth disease type-2D. The GarsP278KY/+ model for Charcot-Marie-Tooth disease type-2D is known best for its early onset severe neuropathic phenotype with findings including reduced axon size, slow conduction velocities and abnormal neuromuscular junction. Muscle involvement remains largely unexamined. We tested the efficacy of neurotrophin 3 gene transfer therapy in two Gars mutants with severe (GarsP278KY/+ ) and milder (GarsΔETAQ/+ ) phenotypes via intramuscular injection of adeno-associated virus setoype-1, triple tandem muscle creatine kinase promoter, neurotrophin 3 (AAV1.tMCK.NT-3) at 1 × 1011 vg dose. In the GarsP278KY/+ mice, the treatment efficacy was assessed at 12 weeks post-injection using rotarod test, electrophysiology and detailed quantitative histopathological studies of the peripheral nervous system including neuromuscular junction and muscle. Neurotrophin 3 gene transfer therapy in GarsP278KY/+ mice resulted in significant functional and electrophysiological improvements, supported with increases in myelin thickness and improvements in the denervated status of neuromuscular junctions as well as increases in muscle fibre size along with attenuation of myopathic changes. Improvements in the milder phenotype GarsΔETAQ/+ was less pronounced. Furthermore, oxidative enzyme histochemistry in muscles from Gars mutants revealed alterations in the content and distribution of oxidative enzymes with increased expression levels of Pgc1a. Cox1, Cox3 and Atp5d transcripts were significantly decreased suggesting that the muscle phenotype might be related to mitochondrial dysfunction. Neurotrophin 3 gene therapy attenuated these abnormalities in the muscle. This study shows that neurotrophin 3 gene transfer therapy has disease modifying effect in a mouse model for Charcot-Marie-Tooth disease type-2D, leading to meaningful improvements in peripheral nerve myelination and neuromuscular junction integrity as well as in a unique myopathic process, associated with mitochondria dysfunction, all in combination contributing to functional outcome. Based on the multiple biological effects of this versatile molecule, we predict neurotrophin 3 has the potential to be beneficial in other aminoacyl-tRNA synthetase-linked Charcot-Marie-Tooth disease subtypes.
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Affiliation(s)
- Burcak Ozes
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Kyle Moss
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Morgan Myers
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Alicia Ridgley
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Lei Chen
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Darren Murrey
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Zarife Sahenk
- Department of Pediatrics, Center for Gene Therapy, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA.,Department of Pediatrics and Neurology, Nationwide Children's Hospital and The Ohio State University, Columbus, OH 43205, USA.,Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH 43205, USA
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17
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Mou Y, Dein J, Chen Z, Jagdale M, Li XJ. MFN2 Deficiency Impairs Mitochondrial Transport and Downregulates Motor Protein Expression in Human Spinal Motor Neurons. Front Mol Neurosci 2021; 14:727552. [PMID: 34602978 PMCID: PMC8482798 DOI: 10.3389/fnmol.2021.727552] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/26/2021] [Indexed: 11/13/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is one of the most common genetically inherited neurological disorders and CMT type 2A (CMT 2A) is caused by dominant mutations in the mitofusin-2 (MFN2) gene. MFN2 is located in the outer mitochondrial membrane and is a mediator of mitochondrial fusion, with an essential role in maintaining normal neuronal functions. Although loss of MFN2 induces axonal neuropathy, the detailed mechanism by which MFN2 deficiency results in axonal degeneration of human spinal motor neurons remains largely unknown. In this study, we generated MFN2-knockdown human embryonic stem cell (hESC) lines using lentivirus expressing MFN2 short hairpin RNA (shRNA). Using these hESC lines, we found that MFN2 loss did not affect spinal motor neuron differentiation from hESCs but resulted in mitochondrial fragmentation and dysfunction as determined by live-cell imaging. Notably, MFN2-knockodwn spinal motor neurons exhibited CMT2A disease-related phenotypes, including extensive perikaryal inclusions of phosphorylated neurofilament heavy chain (pNfH), frequent axonal swellings, and increased pNfH levels in long-term cultures. Importantly, MFN2 deficit impaired anterograde and retrograde mitochondrial transport within axons, and reduced the mRNA and protein levels of kinesin and dynein, indicating the interfered motor protein expression induced by MFN2 deficiency. Our results reveal that MFN2 knockdown induced axonal degeneration of spinal motor neurons and defects in mitochondrial morphology and function. The impaired mitochondrial transport in MFN2-knockdown spinal motor neurons is mediated, at least partially, by the altered motor proteins, providing potential therapeutic targets for rescuing axonal degeneration of spinal motor neurons in CMT2A disease.
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Affiliation(s)
- Yongchao Mou
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Joshua Dein
- MD Program, University of Illinois College of Medicine Rockford, Rockford, IL, United States
| | - Zhenyu Chen
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Mrunali Jagdale
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Xue-Jun Li
- Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, Rockford, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
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18
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Lorenzoni PJ, Kay CSK, Ducci RDP, Fustes OJH, Werneck LC, Scola RH. Charcot-Marie-Tooth disease type 4C associated with myasthenia gravis: coincidental or a foreseeable association? Neurol Sci 2021; 43:705-707. [PMID: 34532771 DOI: 10.1007/s10072-021-05591-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 09/02/2021] [Indexed: 11/26/2022]
Abstract
We reported one patient with Charcot-Marie-Tooth type 4C (CMT4C) who developed seropositive myasthenia gravis. Neuromuscular junction alterations in CMT4C patients have not yet been reported. However, few patients have been reported to simultaneously have MG and CMT, but none with CMT4C. Our report suggests that additional research is required to confirm whether genetic neuropathies may predispose to MG.
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Affiliation(s)
- Paulo José Lorenzoni
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal Do Paraná (UFPR), Curitiba, 80060-900, Brazil.
| | - Claudia Suemi Kamoi Kay
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal Do Paraná (UFPR), Curitiba, 80060-900, Brazil
| | - Renata Dal-Prá Ducci
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal Do Paraná (UFPR), Curitiba, 80060-900, Brazil
| | - Otto Jesus Hernandez Fustes
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal Do Paraná (UFPR), Curitiba, 80060-900, Brazil
| | - Lineu Cesar Werneck
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal Do Paraná (UFPR), Curitiba, 80060-900, Brazil
| | - Rosana Herminia Scola
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal Do Paraná (UFPR), Curitiba, 80060-900, Brazil
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19
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Spaulding EL, Hines TJ, Bais P, Tadenev ALD, Schneider R, Jewett D, Pattavina B, Pratt SL, Morelli KH, Stum MG, Hill DP, Gobet C, Pipis M, Reilly MM, Jennings MJ, Horvath R, Bai Y, Shy ME, Alvarez-Castelao B, Schuman EM, Bogdanik LP, Storkebaum E, Burgess RW. The integrated stress response contributes to tRNA synthetase-associated peripheral neuropathy. Science 2021; 373:1156-1161. [PMID: 34516839 PMCID: PMC8908546 DOI: 10.1126/science.abb3414] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Dominant mutations in ubiquitously expressed transfer RNA (tRNA) synthetase genes cause axonal peripheral neuropathy, accounting for at least six forms of Charcot-Marie-Tooth (CMT) disease. Genetic evidence in mouse and Drosophila models suggests a gain-of-function mechanism. In this study, we used in vivo, cell type–specific transcriptional and translational profiling to show that mutant tRNA synthetases activate the integrated stress response (ISR) through the sensor kinase GCN2 (general control nonderepressible 2). The chronic activation of the ISR contributed to the pathophysiology, and genetic deletion or pharmacological inhibition of Gcn2 alleviated the peripheral neuropathy. The activation of GCN2 suggests that the aberrant activity of the mutant tRNA synthetases is still related to translation and that inhibiting GCN2 or the ISR may represent a therapeutic strategy in CMT.
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Affiliation(s)
- E. L. Spaulding
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | - T. J. Hines
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - P. Bais
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - A. L. D. Tadenev
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - R. Schneider
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - D. Jewett
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - B. Pattavina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - S. L. Pratt
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, 02111 USA
| | - K. H. Morelli
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | - M. G. Stum
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - D. P. Hill
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - C. Gobet
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - M. Pipis
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - M. M. Reilly
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - M. J. Jennings
- Department of Clinical Neuroscience, University of Cambridge, Cambridge, UK
| | - R. Horvath
- Department of Clinical Neuroscience, University of Cambridge, Cambridge, UK
| | - Y. Bai
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - M. E. Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - E. M. Schuman
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | - L. P. Bogdanik
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - E. Storkebaum
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - R. W. Burgess
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, 02111 USA
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20
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Villarroel-Campos D, Schiavo G, Sleigh JN. Dissection, in vivo imaging and analysis of the mouse epitrochleoanconeus muscle. J Anat 2021; 241:1108-1119. [PMID: 34121181 PMCID: PMC9558155 DOI: 10.1111/joa.13478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/07/2021] [Accepted: 05/18/2021] [Indexed: 12/25/2022] Open
Abstract
Analysis of rodent muscles affords an opportunity to glean key insights into neuromuscular development and the detrimental impact of disease‐causing genetic mutations. Muscles of the distal leg, for instance the gastrocnemius and tibialis anterior, are commonly used in such studies with mice and rats. However, thin and flat muscles, which can be dissected, processed and imaged without major disruption to muscle fibres and nerve‐muscle contacts, are more suitable for accurate and detailed analyses of the peripheral motor nervous system. One such wholemount muscle is the predominantly fast twitch epitrochleoanconeus (ETA), which is located in the upper forelimb, innervated by the radial nerve, and contains relatively large and uniformly flat neuromuscular junctions (NMJs). To facilitate incorporation of the ETA into the experimental toolkit of the neuromuscular disease field, here, we describe a simple method for its rapid isolation (<5 min), supported by high‐resolution videos and step‐by‐step images. Furthermore, we outline how the ETA can be imaged in live, anaesthetised mice, to enable examination of dynamic cellular processes occurring at the NMJ and within intramuscular axons, including transport of organelles, such as mitochondria and signalling endosomes. Finally, we present reference data on wild‐type ETA fibre‐type composition in young adult, male C57BL6/J mice. Comparative neuroanatomical studies of different muscles in rodent models of disease can generate critical insights into pathogenesis and pathology; dissection of the wholemount ETA provides the possibility to diversify the repertoire of muscles analysed for this endeavour.
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Affiliation(s)
- David Villarroel-Campos
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
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21
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NMJ-Analyser identifies subtle early changes in mouse models of neuromuscular disease. Sci Rep 2021; 11:12251. [PMID: 34112844 PMCID: PMC8192785 DOI: 10.1038/s41598-021-91094-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 04/26/2021] [Indexed: 12/21/2022] Open
Abstract
The neuromuscular junction (NMJ) is the peripheral synapse formed between a motor neuron axon terminal and a muscle fibre. NMJs are thought to be the primary site of peripheral pathology in many neuromuscular diseases, but innervation/denervation status is often assessed qualitatively with poor systematic criteria across studies, and separately from 3D morphological structure. Here, we describe the development of ‘NMJ-Analyser’, to comprehensively screen the morphology of NMJs and their corresponding innervation status automatically. NMJ-Analyser generates 29 biologically relevant features to quantitatively define healthy and aberrant neuromuscular synapses and applies machine learning to diagnose NMJ degeneration. We validated this framework in longitudinal analyses of wildtype mice, as well as in four different neuromuscular disease models: three for amyotrophic lateral sclerosis (ALS) and one for peripheral neuropathy. We showed that structural changes at the NMJ initially occur in the nerve terminal of mutant TDP43 and FUS ALS models. Using a machine learning algorithm, healthy and aberrant neuromuscular synapses are identified with 95% accuracy, with 88% sensitivity and 97% specificity. Our results validate NMJ-Analyser as a robust platform for systematic and structural screening of NMJs, and pave the way for transferrable, and cross-comparison and high-throughput studies in neuromuscular diseases.
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22
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Zhao Y, Xie L, Shen C, Qi Q, Qin Y, Xing J, Zhou D, Qi Y, Yan Z, Lin X, Dai R, Lin J, Yu W. SIRT2-knockdown rescues GARS-induced Charcot-Marie-Tooth neuropathy. Aging Cell 2021; 20:e13391. [PMID: 34053152 PMCID: PMC8208790 DOI: 10.1111/acel.13391] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 04/10/2021] [Accepted: 05/08/2021] [Indexed: 12/18/2022] Open
Abstract
Charcot‐Marie‐Tooth disease is the most common inherited peripheral neuropathy. Dominant mutations in the glycyl‐tRNA synthetase (GARS) gene cause peripheral nerve degeneration and lead to CMT disease type 2D. The underlying mechanisms of mutations in GARS (GARSCMT2D) in disease pathogenesis are not fully understood. In this study, we report that wild‐type GARS binds the NAD+‐dependent deacetylase SIRT2 and inhibits its deacetylation activity, resulting in the acetylated α‐tubulin, the major substrate of SIRT2. The catalytic domain of GARS tightly interacts with SIRT2, which is the most CMT2D mutation localization. However, CMT2D mutations in GARS cannot inhibit SIRT2 deacetylation, which leads to a decrease of acetylated α‐tubulin. Genetic reduction of SIRT2 in the Drosophila model rescues the GARS‐induced axonal CMT neuropathy and extends the life span. Our findings demonstrate the pathogenic role of SIRT2‐dependent α‐tubulin deacetylation in mutant GARS‐induced neuropathies and provide new perspectives for targeting SIRT2 as a potential therapy against hereditary axonopathies.
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Affiliation(s)
- Yingying Zhao
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Liangguo Xie
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Chao Shen
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Qian Qi
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Yicai Qin
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Juan Xing
- School of Basic Medical Science Southwest Medical University Luzhou China
| | - Dejian Zhou
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Yun Qi
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Zhiqiang Yan
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Xinhua Lin
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Rongyang Dai
- School of Basic Medical Science Southwest Medical University Luzhou China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
| | - Wei Yu
- State Key Laboratory of Genetic Engineering School of Life Sciences Zhongshan Hospital Fudan University Shanghai China
- School of Basic Medical Science Southwest Medical University Luzhou China
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23
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Vinogradova ES, Nikonov OS, Nikonova EY. Associations between Neurological Diseases and Mutations in the Human Glycyl-tRNA Synthetase. BIOCHEMISTRY (MOSCOW) 2021; 86:S12-S23. [PMID: 33827397 PMCID: PMC7905983 DOI: 10.1134/s0006297921140029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Aminoacyl-RNA synthetases (aaRSs) are among the key enzymes of protein biosynthesis. They are responsible for conducting the first step in the protein biosynthesis, namely attaching amino acids to the corresponding tRNA molecules both in cytoplasm and mitochondria. More and more research demonstrates that mutations in the genes encoding aaRSs lead to the development of various neurodegenerative diseases, such as incurable Charcot–Marie–Tooth disease (CMT) and distal spinal muscular atrophy. Some mutations result in the loss of tRNA aminoacylation activity, while other mutants retain their classical enzyme activity. In the latter case, disease manifestations are associated with additional neuron-specific functions of aaRSs. At present, seven aaRSs (GlyRS, TyrRS, AlaRS, HisRS, TrpRS, MetRS, and LysRS) are known to be involved in the CMT etiology with glycyl-tRNA synthetase (GlyRS) being the most studied of them.
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Affiliation(s)
| | - Oleg S Nikonov
- Institute of Protein Research, Pushchino, Moscow Region, 142290, Russia
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24
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Mullen P, Abbott JA, Wellman T, Aktar M, Fjeld C, Demeler B, Ebert AM, Francklyn CS. Neuropathy-associated histidyl-tRNA synthetase variants attenuate protein synthesis in vitro and disrupt axon outgrowth in developing zebrafish. FEBS J 2021; 288:142-159. [PMID: 32543048 PMCID: PMC7736457 DOI: 10.1111/febs.15449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/11/2020] [Accepted: 06/09/2020] [Indexed: 12/13/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) encompasses a set of genetically and clinically heterogeneous neuropathies characterized by length-dependent dysfunction of the peripheral nervous system. Mutations in over 80 diverse genes are associated with CMT, and aminoacyl-tRNA synthetases (ARS) constitute a large gene family implicated in the disease. Despite considerable efforts to elucidate the mechanistic link between ARS mutations and the CMT phenotype, the molecular basis of the pathology is unknown. In this work, we investigated the impact of three CMT-associated substitutions (V155G, Y330C, and R137Q) in the cytoplasmic histidyl-tRNA synthetase (HARS1) on neurite outgrowth and peripheral nervous system development. The model systems for this work included a nerve growth factor-stimulated neurite outgrowth model in rat pheochromocytoma cells (PC12), and a zebrafish line with GFP/red fluorescent protein reporters of sensory and motor neuron development. The expression of CMT-HARS1 mutations led to attenuation of protein synthesis and increased phosphorylation of eIF2α in PC12 cells and was accompanied by impaired neurite and axon outgrowth in both models. Notably, these effects were phenocopied by histidinol, a HARS1 inhibitor, and cycloheximide, a protein synthesis inhibitor. The mutant proteins also formed heterodimers with wild-type HARS1, raising the possibility that CMT-HARS1 mutations cause disease through a dominant-negative mechanism. Overall, these findings support the hypothesis that CMT-HARS1 alleles exert their toxic effect in a neuronal context, and lead to dysregulated protein synthesis. These studies demonstrate the value of zebrafish as a model for studying mutant alleles associated with CMT, and for characterizing the processes that lead to peripheral nervous system dysfunction.
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Affiliation(s)
- Patrick Mullen
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Jamie A Abbott
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Theresa Wellman
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Mahafuza Aktar
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Christian Fjeld
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Borries Demeler
- Department of Chemistry & Biochemistry, University of Lethbridge, Canada
| | - Alicia M Ebert
- Department of Biology, University of Vermont, Burlington, VT, USA
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25
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Guillaud L, El-Agamy SE, Otsuki M, Terenzio M. Anterograde Axonal Transport in Neuronal Homeostasis and Disease. Front Mol Neurosci 2020; 13:556175. [PMID: 33071754 PMCID: PMC7531239 DOI: 10.3389/fnmol.2020.556175] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Neurons are highly polarized cells with an elongated axon that extends far away from the cell body. To maintain their homeostasis, neurons rely extensively on axonal transport of membranous organelles and other molecular complexes. Axonal transport allows for spatio-temporal activation and modulation of numerous molecular cascades, thus playing a central role in the establishment of neuronal polarity, axonal growth and stabilization, and synapses formation. Anterograde and retrograde axonal transport are supported by various molecular motors, such as kinesins and dynein, and a complex microtubule network. In this review article, we will primarily discuss the molecular mechanisms underlying anterograde axonal transport and its role in neuronal development and maturation, including the establishment of functional synaptic connections. We will then provide an overview of the molecular and cellular perturbations that affect axonal transport and are often associated with axonal degeneration. Lastly, we will relate our current understanding of the role of axonal trafficking concerning anterograde trafficking of mRNA and its involvement in the maintenance of the axonal compartment and disease.
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Affiliation(s)
- Laurent Guillaud
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Sara Emad El-Agamy
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Miki Otsuki
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Marco Terenzio
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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26
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Sleigh JN, Mech AM, Aktar T, Zhang Y, Schiavo G. Altered Sensory Neuron Development in CMT2D Mice Is Site-Specific and Linked to Increased GlyRS Levels. Front Cell Neurosci 2020; 14:232. [PMID: 32848623 PMCID: PMC7431706 DOI: 10.3389/fncel.2020.00232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/01/2020] [Indexed: 12/18/2022] Open
Abstract
Dominant, missense mutations in the widely and constitutively expressed GARS1 gene cause peripheral neuropathy that usually begins in adolescence and principally impacts the upper limbs. Caused by a toxic gain-of-function in the encoded glycyl-tRNA synthetase (GlyRS) enzyme, the neuropathology appears to be independent of the canonical role of GlyRS in aminoacylation. Patients display progressive, life-long weakness and wasting of muscles in hands followed by feet, with frequently associated deficits in sensation. When dysfunction is observed in motor and sensory nerves, there is a diagnosis of Charcot-Marie-Tooth disease type 2D (CMT2D), or distal hereditary motor neuropathy type V if the symptoms are purely motor. The cause of this varied sensory involvement remains unresolved, as are the pathomechanisms underlying the selective neurodegeneration characteristic of the disease. We have previously identified in CMT2D mice that neuropathy-causing Gars mutations perturb sensory neuron fate and permit mutant GlyRS to aberrantly interact with neurotrophin receptors (Trks). Here, we extend this work by interrogating further the anatomy and function of the CMT2D sensory nervous system in mutant Gars mice, obtaining several key results: (1) sensory pathology is restricted to neurons innervating the hindlimbs; (2) perturbation of sensory development is not common to all mouse models of neuromuscular disease; (3) in vitro axonal transport of signaling endosomes is not impaired in afferent neurons of all CMT2D mouse models; and (4) Gars expression is selectively elevated in a subset of sensory neurons and linked to sensory developmental defects. These findings highlight the importance of comparative neurological assessment in mouse models of disease and shed light on key proposed neuropathogenic mechanisms in GARS1-linked neuropathy.
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Affiliation(s)
- James N. Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- UK Dementia Research Institute, University College London, London, United Kingdom
| | - Aleksandra M. Mech
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Tahmina Aktar
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Yuxin Zhang
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- UK Dementia Research Institute, University College London, London, United Kingdom
- Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, London, United Kingdom
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27
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Sleigh JN, Mech AM, Schiavo G. Developmental demands contribute to early neuromuscular degeneration in CMT2D mice. Cell Death Dis 2020; 11:564. [PMID: 32703932 PMCID: PMC7378196 DOI: 10.1038/s41419-020-02798-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 12/13/2022]
Abstract
Dominantly inherited, missense mutations in the widely expressed housekeeping gene, GARS1, cause Charcot-Marie-Tooth type 2D (CMT2D), a peripheral neuropathy characterised by muscle weakness and wasting in limb extremities. Mice modelling CMT2D display early and selective neuromuscular junction (NMJ) pathology, epitomised by disturbed maturation and neurotransmission, leading to denervation. Indeed, the NMJ disruption has been reported in several different muscles; however, a systematic comparison of neuromuscular synapses from distinct body locations has yet to be performed. We therefore analysed NMJ development and degeneration across five different wholemount muscles to identify key synaptic features contributing to the distinct pattern of neurodegeneration in CMT2D mice. Denervation was found to occur along a distal-to-proximal gradient, providing a cellular explanation for the greater weakness observed in mutant Gars hindlimbs compared with forelimbs. Nonetheless, muscles from similar locations and innervated by axons of equivalent length showed significant differences in neuropathology, suggestive of additional factors impacting on site-specific neuromuscular degeneration. Defective NMJ development preceded and associated with degeneration, but was not linked to a delay of wild-type NMJ maturation processes. Correlation analyses indicate that muscle fibre type nor synaptic architecture explain the differential denervation of CMT2D NMJs, rather it is the extent of post-natal synaptic growth that predisposes to neurodegeneration. Together, this work improves our understanding of the mechanisms driving synaptic vulnerability in CMT2D and hints at pertinent pathogenic pathways.
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Affiliation(s)
- James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK.
- UK Dementia Research Institute, University College London, London, WC1E 6BT, UK.
| | - Aleksandra M Mech
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
- UK Dementia Research Institute, University College London, London, WC1E 6BT, UK
- Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, London, WC1N 3BG, UK
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28
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Tosolini AP, Sleigh JN. Intramuscular Delivery of Gene Therapy for Targeting the Nervous System. Front Mol Neurosci 2020; 13:129. [PMID: 32765219 PMCID: PMC7379875 DOI: 10.3389/fnmol.2020.00129] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 06/26/2020] [Indexed: 12/11/2022] Open
Abstract
Virus-mediated gene therapy has the potential to deliver exogenous genetic material into specific cell types to promote survival and counteract disease. This is particularly enticing for neuronal conditions, as the nervous system is renowned for its intransigence to therapeutic targeting. Administration of gene therapy viruses into skeletal muscle, where distal terminals of motor and sensory neurons reside, has been shown to result in extensive transduction of cells within the spinal cord, brainstem, and sensory ganglia. This route is minimally invasive and therefore clinically relevant for gene therapy targeting to peripheral nerve soma. For successful transgene expression, viruses administered into muscle must undergo a series of processes, including host cell interaction and internalization, intracellular sorting, long-range retrograde axonal transport, endosomal liberation, and nuclear import. In this review article, we outline key characteristics of major gene therapy viruses—adenovirus, adeno-associated virus (AAV), and lentivirus—and summarize the mechanisms regulating important steps in the virus journey from binding at peripheral nerve terminals to nuclear delivery. Additionally, we describe how neuropathology can negatively influence these pathways, and conclude by discussing opportunities to optimize the intramuscular administration route to maximize gene delivery and thus therapeutic potential.
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Affiliation(s)
- Andrew P Tosolini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.,UK Dementia Research Institute, University College London, London, United Kingdom
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29
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Abstract
Organs-on-chips are broadly defined as microfabricated surfaces or devices designed to engineer cells into microscale tissues with native-like features and then extract physiologically relevant readouts at scale. Because they are generally compatible with patient-derived cells, these technologies can address many of the human relevance limitations of animal models. As a result, organs-on-chips have emerged as a promising new paradigm for patient-specific disease modeling and drug development. Because neuromuscular diseases span a broad range of rare conditions with diverse etiology and complex pathophysiology, they have been especially challenging to model in animals and thus are well suited for organ-on-chip approaches. In this Review, we first briefly summarize the challenges in neuromuscular disease modeling with animal models. Next, we describe a variety of existing organ-on-chip approaches for neuromuscular tissues, including a survey of cell sources for both muscle and nerve, and two- and three-dimensional neuromuscular tissue-engineering techniques. Although researchers have made tremendous advances in modeling neuromuscular diseases on a chip, the remaining challenges in cell sourcing, cell maturity, tissue assembly and readout capabilities limit their integration into the drug development pipeline today. However, as the field advances, models of healthy and diseased neuromuscular tissues on a chip, coupled with animal models, have vast potential as complementary tools for modeling multiple aspects of neuromuscular diseases and identifying new therapeutic strategies. Summary: Modeling neuromuscular diseases is challenging due to their complex etiology and pathophysiology. Here, we review the cell sources and tissue-engineering procedures that are being integrated as emerging neuromuscular disease models.
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Affiliation(s)
- Jeffrey W Santoso
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Megan L McCain
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90089, USA .,Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA 90033, USA
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30
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Prukop T, Wernick S, Boussicault L, Ewers D, Jäger K, Adam J, Winter L, Quintes S, Linhoff L, Barrantes-Freer A, Bartl M, Czesnik D, Zschüntzsch J, Schmidt J, Primas G, Laffaire J, Rinaudo P, Brureau A, Nabirotchkin S, Schwab MH, Nave KA, Hajj R, Cohen D, Sereda MW. Synergistic PXT3003 therapy uncouples neuromuscular function from dysmyelination in male Charcot-Marie-Tooth disease type 1A (CMT1A) rats. J Neurosci Res 2020; 98:1933-1952. [PMID: 32588471 DOI: 10.1002/jnr.24679] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/13/2020] [Accepted: 05/31/2020] [Indexed: 12/11/2022]
Abstract
Charcot-Marie-Tooth disease 1 A (CMT1A) is caused by an intrachromosomal duplication of the gene encoding for PMP22 leading to peripheral nerve dysmyelination, axonal loss, and progressive muscle weakness. No therapy is available. PXT3003 is a low-dose combination of baclofen, naltrexone, and sorbitol which has been shown to improve disease symptoms in Pmp22 transgenic rats, a bona fide model of CMT1A disease. However, the superiority of PXT3003 over its single components or dual combinations have not been tested. Here, we show that in a dorsal root ganglion (DRG) co-culture system derived from transgenic rats, PXT3003 induced myelination when compared to its single and dual components. Applying a clinically relevant ("translational") study design in adult male CMT1A rats for 3 months, PXT3003, but not its dual components, resulted in improved performance in behavioral motor and sensory endpoints when compared to placebo. Unexpectedly, we observed only a marginally increased number of myelinated axons in nerves from PXT3003-treated CMT1A rats. However, in electrophysiology, motor latencies correlated with increased grip strength indicating a possible effect of PXT3003 on neuromuscular junctions (NMJs) and muscle fiber pathology. Indeed, PXT3003-treated CMT1A rats displayed an increased perimeter of individual NMJs and a larger number of functional NMJs. Moreover, muscles of PXT3003 CMT1A rats displayed less neurogenic atrophy and a shift toward fast contracting muscle fibers. We suggest that ameliorated motor function in PXT3003-treated CMT1A rats result from restored NMJ function and muscle innervation, independent from myelination.
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Affiliation(s)
- Thomas Prukop
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, Germany
| | - Stephanie Wernick
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - David Ewers
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Karoline Jäger
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Julia Adam
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Lorenz Winter
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Susanne Quintes
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Lisa Linhoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Michael Bartl
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Dirk Czesnik
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Jana Zschüntzsch
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Jens Schmidt
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | | | | | | | | | | | - Markus H Schwab
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | | | | | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
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31
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Mech AM, Brown AL, Schiavo G, Sleigh JN. Morphological variability is greater at developing than mature mouse neuromuscular junctions. J Anat 2020; 237:603-617. [PMID: 32533580 PMCID: PMC7495279 DOI: 10.1111/joa.13228] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/04/2020] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
The neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post‐synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, thereby enabling the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, how synaptic morphology changes during development, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi‐automated workflow called NMJ‐morph to quantify features of pre‐ and post‐synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild‐type mice were dissected and compared at immature (post‐natal day, P7) and early adult (P31−32) timepoints. The inter‐muscular variability was greater in mature post‐synaptic AChR morphology than that of the pre‐synaptic motor neuron terminal. Moreover, the developing NMJ showed greater differences across muscles than the mature synapse, perhaps due to the observed distinctions in synaptic growth between muscles. Nevertheless, the amount of nerve to muscle contact was consistent, suggesting that pathological denervation can be reliably compared across different muscles in mouse models of neurodegeneration. Additionally, mature post‐synaptic endplate diameters correlated with fibre type, independently of muscle fibre diameter. Altogether, this work provides detailed information on healthy pre‐ and post‐synaptic NMJ morphology from five anatomically and functionally distinct mouse muscles, delivering useful reference data for future comparison with neuromuscular disease models.
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Affiliation(s)
- Aleksandra M Mech
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Anna-Leigh Brown
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK.,Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, London, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
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32
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Morelli KH, Griffin LB, Pyne NK, Wallace LM, Fowler AM, Oprescu SN, Takase R, Wei N, Meyer-Schuman R, Mellacheruvu D, Kitzman JO, Kocen SG, Hines TJ, Spaulding EL, Lupski JR, Nesvizhskii A, Mancias P, Butler IJ, Yang XL, Hou YM, Antonellis A, Harper SQ, Burgess RW. Allele-specific RNA interference prevents neuropathy in Charcot-Marie-Tooth disease type 2D mouse models. J Clin Invest 2020; 129:5568-5583. [PMID: 31557132 DOI: 10.1172/jci130600] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 09/10/2019] [Indexed: 12/24/2022] Open
Abstract
Gene therapy approaches are being deployed to treat recessive genetic disorders by restoring the expression of mutated genes. However, the feasibility of these approaches for dominantly inherited diseases - where treatment may require reduction in the expression of a toxic mutant protein resulting from a gain-of-function allele - is unclear. Here we show the efficacy of allele-specific RNAi as a potential therapy for Charcot-Marie-Tooth disease type 2D (CMT2D), caused by dominant mutations in glycyl-tRNA synthetase (GARS). A de novo mutation in GARS was identified in a patient with a severe peripheral neuropathy, and a mouse model precisely recreating the mutation was produced. These mice developed a neuropathy by 3-4 weeks of age, validating the pathogenicity of the mutation. RNAi sequences targeting mutant GARS mRNA, but not wild-type, were optimized and then packaged into AAV9 for in vivo delivery. This almost completely prevented the neuropathy in mice treated at birth. Delaying treatment until after disease onset showed modest benefit, though this effect decreased the longer treatment was delayed. These outcomes were reproduced in a second mouse model of CMT2D using a vector specifically targeting that allele. The effects were dose dependent, and persisted for at least 1 year. Our findings demonstrate the feasibility of AAV9-mediated allele-specific knockdown and provide proof of concept for gene therapy approaches for dominant neuromuscular diseases.
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Affiliation(s)
- Kathryn H Morelli
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, USA
| | - Laurie B Griffin
- Program in Cellular and Molecular Biology, and.,Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Nettie K Pyne
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Lindsay M Wallace
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Allison M Fowler
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Stephanie N Oprescu
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Ryuichi Takase
- Department of Biochemistry and Molecular Biochemistry, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Na Wei
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | | | - Dattatreya Mellacheruvu
- Department of Pathology, and.,Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, USA
| | - Jacob O Kitzman
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, and.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA
| | - Alexey Nesvizhskii
- Department of Pathology, and.,Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, USA
| | - Pedro Mancias
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, and Children's Memorial Hermann Hospital, Houston, Texas, USA
| | - Ian J Butler
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, and Children's Memorial Hermann Hospital, Houston, Texas, USA
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biochemistry, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Anthony Antonellis
- Program in Cellular and Molecular Biology, and.,Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Scott Q Harper
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, USA
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33
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Perez-Siles G, Cutrupi A, Ellis M, Screnci R, Mao D, Uesugi M, Yiu EM, Ryan MM, Choi BO, Nicholson G, Kennerson ML. Energy metabolism and mitochondrial defects in X-linked Charcot-Marie-Tooth (CMTX6) iPSC-derived motor neurons with the p.R158H PDK3 mutation. Sci Rep 2020; 10:9262. [PMID: 32504000 PMCID: PMC7275085 DOI: 10.1038/s41598-020-66266-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/18/2020] [Indexed: 11/09/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) is a group of inherited diseases clinically and genetically heterogenous, characterised by length dependent degeneration of axons of the peripheral nervous system. A missense mutation (p.R158H) in the pyruvate dehydrogenase kinase 3 gene (PDK3) has been identified as the genetic cause for an X-linked form of CMT (CMTX6) in two unrelated families. PDK3 is one of four PDK isoenzymes that regulate the activity of the pyruvate dehydrogenase complex (PDC). The balance between kinases (PDKs) and phosphatases (PDPs) determines the extend of oxidative decarboxylation of pyruvate to generate acetyl CoA, critically linking glycolysis and the energy producing Krebs cycle. We had shown the p.R158H mutation causes hyperactivity of PDK3 and CMTX6 fibroblasts show hyperphosphorylation of PDC, leading to reduced PDC activity and ATP production. In this manuscript we have generated induced pluripotent stem cells (iPSCs) by re-programming CMTX6 fibroblasts (iPSCCMTX6). We also have engineered an isogenic control (iPSCisogenic) and demonstrated that genetic correction of the p.R158H mutation reverses the CMTX6 phenotype. Patient-derived motor neurons (MNCMTX6) show increased phosphorylation of the PDC, energy metabolism defects and mitochondrial abnormalities, including reduced velocity of trafficking mitochondria in the affected axons. Treatment of the MNCMTX6 with a PDK inhibitor reverses PDC hyperphosphorylation and the associated functional deficits founds in the patient motor neurons, demonstrating that the MNCMTX6 and MNisogenic motor neurons provide an excellent neuronal system for compound screening approaches to identify drugs for the treatment of CMTX6.
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Affiliation(s)
- G Perez-Siles
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, Australia. .,Sydney Medical School, University of Sydney, Sydney, Australia.
| | - A Cutrupi
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
| | - M Ellis
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, Australia
| | - R Screnci
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - D Mao
- Institute for Integrated Cell-Material Sciences and Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - M Uesugi
- Institute for Integrated Cell-Material Sciences and Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Eppie M Yiu
- Department of Neurology, Royal Children's Hospital, Flemington Road, Parkville, VIC, Australia.,Neuroscience Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Monique M Ryan
- Department of Neurology, Royal Children's Hospital, Flemington Road, Parkville, VIC, Australia.,Neuroscience Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - B O Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - G Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, Australia.,Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, Australia
| | - M L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, Australia. .,Sydney Medical School, University of Sydney, Sydney, Australia. .,Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, Australia.
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34
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Soh MS, Cheng X, Vijayaraghavan T, Vernon A, Liu J, Neumann B. Disruption of genes associated with Charcot-Marie-Tooth type 2 lead to common behavioural, cellular and molecular defects in Caenorhabditis elegans. PLoS One 2020; 15:e0231600. [PMID: 32294113 PMCID: PMC7159224 DOI: 10.1371/journal.pone.0231600] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/26/2020] [Indexed: 11/23/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is an inherited peripheral motor and sensory neuropathy. The disease is divided into demyelinating (CMT1) and axonal (CMT2) neuropathies, and although we have gained molecular information into the details of CMT1 pathology, much less is known about CMT2. Due to its clinical and genetic heterogeneity, coupled with a lack of animal models, common underlying mechanisms remain elusive. In order to gain an understanding of the normal function of genes associated with CMT2, and to draw direct comparisons between them, we have studied the behavioural, cellular and molecular consequences of mutating nine different genes in the nematode Caenorhabditis elegans (lin-41/TRIM2, dyn-1/DNM2, unc-116/KIF5A, fzo-1/MFN2, osm-9/TRPV4, cua-1/ATP7A, hsp-25/HSPB1, hint-1/HINT1, nep-2/MME). We show that C. elegans defective for these genes display debilitated movement in crawling and swimming assays. Severe morphological defects in cholinergic motors neurons are also evident in two of the mutants (dyn-1 and unc-116). Furthermore, we establish methods for quantifying muscle morphology and use these to demonstrate that loss of muscle structure occurs in the majority of mutants studied. Finally, using electrophysiological recordings of neuromuscular junction (NMJ) activity, we uncover reductions in spontaneous postsynaptic current frequency in lin-41, dyn-1, unc-116 and fzo-1 mutants. By comparing the consequences of mutating numerous CMT2-related genes, this study reveals common deficits in muscle structure and function, as well as NMJ signalling when these genes are disrupted.
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Affiliation(s)
- Ming S. Soh
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Xinran Cheng
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Tarika Vijayaraghavan
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Arwen Vernon
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Jie Liu
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
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35
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Beijer D, Sisto A, Van Lent J, Baets J, Timmerman V. Defects in Axonal Transport in Inherited Neuropathies. J Neuromuscul Dis 2020; 6:401-419. [PMID: 31561383 PMCID: PMC6918914 DOI: 10.3233/jnd-190427] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Axonal transport is a highly complex process essential for sustaining proper neuronal functioning. Disturbances can result in an altered neuronal homeostasis, aggregation of cargoes, and ultimately a dying-back degeneration of neurons. The impact of dysfunction in axonal transport is shown by genetic defects in key proteins causing a broad spectrum of neurodegenerative diseases, including inherited peripheral neuropathies. In this review, we provide an overview of the cytoskeletal components, molecular motors and adaptor proteins involved in axonal transport mechanisms and their implication in neuronal functioning. In addition, we discuss the involvement of axonal transport dysfunction in neurodegenerative diseases with a particular focus on inherited peripheral neuropathies. Lastly, we address some recent scientific advances most notably in therapeutic strategies employed in the area of axonal transport, patient-derived iPSC models, in vivo animal models, antisense-oligonucleotide treatments, and novel chemical compounds.
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Affiliation(s)
- Danique Beijer
- Neurogenetics Research Group, Department of Medical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Angela Sisto
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Jonas Van Lent
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Jonathan Baets
- Neurogenetics Research Group, Department of Medical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium.,Neurology Department, University Hospital Antwerp, Antwerpen, Belgium
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
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36
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Bisetto S, Wright MC, Nowak RA, Lepore AC, Khurana TS, Loro E, Philp NJ. New Insights into the Lactate Shuttle: Role of MCT4 in the Modulation of the Exercise Capacity. iScience 2019; 22:507-518. [PMID: 31837519 PMCID: PMC6920289 DOI: 10.1016/j.isci.2019.11.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/30/2019] [Accepted: 11/22/2019] [Indexed: 12/31/2022] Open
Abstract
Lactate produced by muscle during high-intensity activity is an important end product of glycolysis that supports whole body metabolism. The lactate shuttle model suggested that lactate produced by glycolytic muscle fibers is utilized by oxidative fibers. MCT4 is a proton coupled monocarboxylate transporter preferentially expressed in glycolytic muscle fibers and facilitates the lactate efflux. Here we investigated the exercise capacity of mice with disrupted lactate shuttle due to global deletion of MCT4 (MCT4-/-) or muscle-specific deletion of the accessory protein Basigin (iMSBsg-/-). Although MCT4-/- and iMSBsg-/- mice have normal muscle morphology and contractility, only MCT4-/- mice exhibit an exercise intolerant phenotype. In vivo measurements of compound muscle action potentials showed a decrement in the evoked response in the MCT4-/- mice. This was accompanied by a significant structural degeneration of the neuromuscular junctions (NMJs). We propose that disruption of the lactate shuttle impacts motor function and destabilizes the motor unit.
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Affiliation(s)
- Sara Bisetto
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, Glenside, PA 19038, USA
| | - Romana A Nowak
- Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA
| | - Angelo C Lepore
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emanuele Loro
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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37
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Transcriptional dysregulation by a nucleus-localized aminoacyl-tRNA synthetase associated with Charcot-Marie-Tooth neuropathy. Nat Commun 2019; 10:5045. [PMID: 31695036 PMCID: PMC6834567 DOI: 10.1038/s41467-019-12909-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 10/01/2019] [Indexed: 12/02/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a length-dependent peripheral neuropathy. The aminoacyl-tRNA synthetases constitute the largest protein family implicated in CMT. Aminoacyl-tRNA synthetases are predominantly cytoplasmic, but are also present in the nucleus. Here we show that a nuclear function of tyrosyl-tRNA synthetase (TyrRS) is implicated in a Drosophila model of CMT. CMT-causing mutations in TyrRS induce unique conformational changes, which confer capacity for aberrant interactions with transcriptional regulators in the nucleus, leading to transcription factor E2F1 hyperactivation. Using neuronal tissues, we reveal a broad transcriptional regulation network associated with wild-type TyrRS expression, which is disturbed when a CMT-mutant is expressed. Pharmacological inhibition of TyrRS nuclear entry with embelin reduces, whereas genetic nuclear exclusion of mutant TyrRS prevents hallmark phenotypes of CMT in the Drosophila model. These data highlight that this translation factor may contribute to transcriptional regulation in neurons, and suggest a therapeutic strategy for CMT. Tyrosyl-tRNA synthetase (TyrRS) is a translation factor and predominantly cytoplasmic, but can also be found in the nucleus. Here authors show using a fly model of Charcot-Marie-Tooth (CMT) disease that nuclear localization of mutant TyrRS contributes to the CMT-like phenotype.
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38
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Benoy V, Van Helleputte L, Prior R, d'Ydewalle C, Haeck W, Geens N, Scheveneels W, Schevenels B, Cader MZ, Talbot K, Kozikowski AP, Vanden Berghe P, Van Damme P, Robberecht W, Van Den Bosch L. HDAC6 is a therapeutic target in mutant GARS-induced Charcot-Marie-Tooth disease. Brain 2019; 141:673-687. [PMID: 29415205 PMCID: PMC5837793 DOI: 10.1093/brain/awx375] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/20/2017] [Indexed: 01/01/2023] Open
Abstract
Peripheral nerve axons require a well-organized axonal microtubule network for efficient transport to ensure the constant crosstalk between soma and synapse. Mutations in more than 80 different genes cause Charcot-Marie-Tooth disease, which is the most common inherited disorder affecting peripheral nerves. This genetic heterogeneity has hampered the development of therapeutics for Charcot-Marie-Tooth disease. The aim of this study was to explore whether histone deacetylase 6 (HDAC6) can serve as a therapeutic target focusing on the mutant glycyl-tRNA synthetase (GlyRS/GARS)-induced peripheral neuropathy. Peripheral nerves and dorsal root ganglia from the C201R mutant Gars mouse model showed reduced acetylated α-tubulin levels. In primary dorsal root ganglion neurons, mutant GlyRS affected neurite length and disrupted normal mitochondrial transport. We demonstrated that GlyRS co-immunoprecipitated with HDAC6 and that this interaction was blocked by tubastatin A, a selective inhibitor of the deacetylating function of HDAC6. Moreover, HDAC6 inhibition restored mitochondrial axonal transport in mutant GlyRS-expressing neurons. Systemic delivery of a specific HDAC6 inhibitor increased α-tubulin acetylation in peripheral nerves and partially restored nerve conduction and motor behaviour in mutant Gars mice. Our study demonstrates that α-tubulin deacetylation and disrupted axonal transport may represent a common pathogenic mechanism underlying Charcot-Marie-Tooth disease and it broadens the therapeutic potential of selective HDAC6 inhibition to other genetic forms of axonal Charcot-Marie-Tooth disease.
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Affiliation(s)
- Veronick Benoy
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Lawrence Van Helleputte
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Robert Prior
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Constantin d'Ydewalle
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Wanda Haeck
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Natasja Geens
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Wendy Scheveneels
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Begga Schevenels
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - M Zameel Cader
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.,The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Alan P Kozikowski
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago, Chicago, USA
| | - Pieter Vanden Berghe
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Philip Van Damme
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,University Hospitals Leuven, Department of Neurology, Leuven, Belgium
| | - Wim Robberecht
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,University Hospitals Leuven, Department of Neurology, Leuven, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.,VIB - Center for Brain and Disease Research, Laboratory of Neurobiology, Leuven, Belgium
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Wei N, Zhang Q, Yang XL. Neurodegenerative Charcot-Marie-Tooth disease as a case study to decipher novel functions of aminoacyl-tRNA synthetases. J Biol Chem 2019; 294:5321-5339. [PMID: 30643024 DOI: 10.1074/jbc.rev118.002955] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that catalyze the first reaction in protein biosynthesis, namely the charging of transfer RNAs (tRNAs) with their cognate amino acids. aaRSs have been increasingly implicated in dominantly and recessively inherited human diseases. The most common aaRS-associated monogenic disorder is the incurable neurodegenerative disease Charcot-Marie-Tooth neuropathy (CMT), caused by dominant mono-allelic mutations in aaRSs. With six currently known members (GlyRS, TyrRS, AlaRS, HisRS, TrpRS, and MetRS), aaRSs represent the largest protein family implicated in CMT etiology. After the initial discovery linking aaRSs to CMT, the field has progressed from understanding whether impaired tRNA charging is a critical component of this disease to elucidating the specific pathways affected by CMT-causing mutations in aaRSs. Although many aaRS CMT mutants result in loss of tRNA aminoacylation function, animal genetics studies demonstrated that dominant mutations in GlyRS cause CMT through toxic gain-of-function effects, which also may apply to other aaRS-linked CMT subtypes. The CMT-causing mechanism is likely to be multifactorial and involves multiple cellular compartments, including the nucleus and the extracellular space, where the normal WT enzymes also appear. Thus, the association of aaRSs with neuropathy is relevant to discoveries indicating that aaRSs also have nonenzymatic regulatory functions that coordinate protein synthesis with other biological processes. Through genetic, functional, and structural analyses, commonalities among different mutations and different aaRS-linked CMT subtypes have begun to emerge, providing insights into the nonenzymatic functions of aaRSs and the pathogenesis of aaRS-linked CMT to guide therapeutic development to treat this disease.
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Affiliation(s)
- Na Wei
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Qian Zhang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Xiang-Lei Yang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
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40
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Cipriani S, Phan V, Médard JJ, Horvath R, Lochmüller H, Chrast R, Roos A, Spendiff S. Neuromuscular Junction Changes in a Mouse Model of Charcot-Marie-Tooth Disease Type 4C. Int J Mol Sci 2018; 19:ijms19124072. [PMID: 30562927 PMCID: PMC6320960 DOI: 10.3390/ijms19124072] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/06/2018] [Accepted: 12/14/2018] [Indexed: 01/08/2023] Open
Abstract
The neuromuscular junction (NMJ) appears to be a site of pathology in a number of peripheral nerve diseases. Charcot-Marie-Tooth (CMT) 4C is an autosomal recessive, early onset, demyelinating neuropathy. Numerous mutations in the SH3TC2 gene have been shown to underlie the condition often associated with scoliosis, foot deformities, and reduced nerve conduction velocities. Mice with exon 1 of the Sh3tc2 gene knocked out demonstrate many of the features seen in patients. To determine if NMJ pathology is contributory to the pathomechanisms of CMT4C we examined NMJs in the gastrocnemius muscle of SH3TC2-deficient mice. In addition, we performed proteomic assessment of the sciatic nerve to identify protein factors contributing to the NMJ alterations and the survival of demyelinated axons. Morphological and gene expression analysis of NMJs revealed a lack of continuity between the pre- and post-synaptic apparatus, increases in post-synaptic fragmentation and dispersal, and an increase in expression of the gamma subunit of the acetylcholine receptor. There were no changes in axonal width or the number of axonal inputs to the NMJ. Proteome investigations of the sciatic nerve revealed altered expression of extracellular matrix proteins important for NMJ integrity. Together these observations suggest that CMT4C pathology includes a compromised NMJ even in the absence of changes to the innervating axon.
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Affiliation(s)
- Silvia Cipriani
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.
- INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, 20132 Milan, Italy.
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.
| | - Vietxuan Phan
- Leibniz-Institut für Analytische Wissenschaften -ISAS- e.V.; Otto-Hahn-Strasse 6b, 44227 Dortmund, Germany.
| | - Jean-Jacques Médard
- Department of Neuroscience, Karolinska Institutet, 171 65 Stockholm, Sweden.
- Department of Clinical Neuroscience, Karolinska Institutet, 171 65 Stockholm, Sweden.
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, John Van Geest Cambridge Centre for Brain Repair, Forvie, Robinson way, Cambridge Biomedical Campus, Cambridge CB2 0PY, UK.
| | - Hanns Lochmüller
- Department of Neuropediatrics and Muscle Disorders, Medical Center-University of Freiburg, Mathildenstrasse 1, 79106 Freiburg, Germany.
- Centro Nacional de Análisis Genómico, Center for Genomic Regulation, Barcelona Institute of Science and Technology, Baldri I reixac 4, 08028 Barcelona, Spain.
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada.
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Riverside Drive, Ottawa, ON K1H 7X5, Canada.
| | - Roman Chrast
- Department of Neuroscience, Karolinska Institutet, 171 65 Stockholm, Sweden.
- Department of Clinical Neuroscience, Karolinska Institutet, 171 65 Stockholm, Sweden.
| | - Andreas Roos
- Leibniz-Institut für Analytische Wissenschaften -ISAS- e.V.; Otto-Hahn-Strasse 6b, 44227 Dortmund, Germany.
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, Centre for Neuromuscular Disorders in Children, University Children's Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany.
| | - Sally Spendiff
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada.
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41
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Phan V, Cox D, Cipriani S, Spendiff S, Buchkremer S, O'Connor E, Horvath R, Goebel HH, Hathazi D, Lochmüller H, Straka T, Rudolf R, Weis J, Roos A. SIL1 deficiency causes degenerative changes of peripheral nerves and neuromuscular junctions in fish, mice and human. Neurobiol Dis 2018; 124:218-229. [PMID: 30468864 DOI: 10.1016/j.nbd.2018.11.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 10/21/2018] [Accepted: 11/19/2018] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Marinesco-Sjögren Syndrome (MSS) is a rare neuromuscular condition caused by recessive mutations in the SIL1 gene resulting in the absence of functional SIL1 protein, a co-chaperone for the major ER chaperone, BiP. As BiP is decisive for proper protein processing, loss of SIL1 results in the accumulation of misshaped proteins. This accumulation likely damages and destroys cells in vulnerable tissues, leading to congenital cataracts, cerebellar ataxia, vacuolar myopathy and other MSS phenotypes. Whether the peripheral nervous system (PNS) is affected in MSS has not been conclusively shown. METHODS To study PNS vulnerability in MSS, intramuscular nerves fibres from MSS patients and from SIL1-deficient mice (woozy) as well as sciatic nerves and neuromuscular junctions (NMJ) from these mice have been investigated via transmission electron microscopic and immunofluorescence studies accompanied by transcript studies and unbiased proteomic profiling. In addition, PNS and NMJ integrity were analyzed via immunofluorescence studies in an MSS-zebrafish model which has been generated for that purpose. RESULTS Electron microscopy revealed morphological changes indicative of impaired autophagy and mitochondrial maintenance in distal axons and in Schwann cells. Moreover, changes of the morphology of NMJs as well as of transcripts encoding proteins important for NMJ function were detected in woozy mice. These findings were in line with a grossly abnormal structure of NMJs in SIL1-deficient zebrafish embryos. Proteome profiling of sciatic nerve specimens from woozy mice revealed altered levels of proteins implicated in neuronal maintenance suggesting the activation of compensatory mechanisms. CONCLUSION Taken together, our combined data expand the spectrum of tissues affected by SIL1-loss and suggest that impaired neuromuscular transmission might be part of MSS pathophysiology.
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Affiliation(s)
- Vietxuan Phan
- Leibniz-Institut für Analytische Wissenschaften, ISAS, e.V. Dortmund, 44227, Dortmund, Germany.
| | - Dan Cox
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
| | - Silvia Cipriani
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK; Department of Neuromotor and Biomedical Sciences, Pathology Unit, University of Bologna, Bologna, Italy.
| | - Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada; Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada.
| | - Stephan Buchkremer
- Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, 52074, Germany.
| | - Emily O'Connor
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK. emily.o'
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK.
| | | | - Denisa Hathazi
- Leibniz-Institut für Analytische Wissenschaften, ISAS, e.V. Dortmund, 44227, Dortmund, Germany.
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada; Department of Neuropediatrics and Muscle Disorders, Medical Center, University of Freiburg, Faculty of Medicine, Freiburg, Germany; Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada
| | - Tatjana Straka
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany; Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany; Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany; Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany; Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
| | - Joachim Weis
- Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, 52074, Germany.
| | - Andreas Roos
- Leibniz-Institut für Analytische Wissenschaften, ISAS, e.V. Dortmund, 44227, Dortmund, Germany; Institute of Neuropathology, University Hospital RWTH Aachen, Aachen, 52074, Germany; Pediatric Neurology, University Childrens Hospital, University of Duisburg-Essen, Faculty of Medicine, Essen, Germany.
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42
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Montes-Chinea NI, Guan Z, Coutts M, Vidal C, Courel S, Rebelo AP, Abreu L, Zuchner S, Littleton JT, Saporta MA. Identification of a new SYT2 variant validates an unusual distal motor neuropathy phenotype. NEUROLOGY-GENETICS 2018; 4:e282. [PMID: 30533528 PMCID: PMC6244021 DOI: 10.1212/nxg.0000000000000282] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/21/2018] [Indexed: 11/15/2022]
Abstract
Objective To report a new SYT2 missense mutation causing distal hereditary motor neuropathy and presynaptic neuromuscular junction (NMJ) transmission dysfunction. Methods We report a multigenerational family with a new missense mutation, c. 1112T>A (p. Ile371Lys), in the C2B domain of SYT2, describe the clinical and electrophysiologic phenotype associated with this variant, and validate its pathogenicity in a Drosophila model. Results Both proband and her mother present a similar clinical phenotype characterized by a slowly progressive, predominantly motor neuropathy and clear evidence of presynaptic NMJ dysfunction on nerve conduction studies. Validation of this new variant was accomplished by characterization of the mutation homologous to the human c. 1112T>A variant in Drosophila, confirming its dominant-negative effect on neurotransmitter release. Conclusions This report provides further confirmation of the role of SYT2 in human disease and corroborates the resultant unique clinical phenotype consistent with heriditary distal motor neuropathy. SYT2-related motor neuropathy is a rare disease but should be suspected in patients presenting with a combination of presynaptic NMJ dysfunction (resembling Lambert-Eaton myasthenic syndrome) and a predominantly motor neuropathy, especially in the context of a positive family history.
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Affiliation(s)
- Nataly I Montes-Chinea
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Zhuo Guan
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Marcella Coutts
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Cecilia Vidal
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Steve Courel
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Adriana P Rebelo
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Lisa Abreu
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Stephan Zuchner
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - J Troy Littleton
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Mario A Saporta
- Department of Neurology (N.I.M.-C., M.C., C.V., M.A.S.), University of Miami Miller School of Medicine FL; Department of Biology (Z.G., J.T.L.) and Department of Brain and Cognitive Sciences (Z.G., J.T.L.), The Picower Institute for Learning & Memory, Massachusetts Institute of Technology, Cambridge; and Department of Human Genetics (S.C., A.P.R., L.A., S.Z., M.A.S.), Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
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43
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Boczonadi V, Meyer K, Gonczarowska-Jorge H, Griffin H, Roos A, Bartsakoulia M, Bansagi B, Ricci G, Palinkas F, Zahedi RP, Bruni F, Kaspar B, Lochmüller H, Boycott KM, Müller JS, Horvath R. Mutations in glycyl-tRNA synthetase impair mitochondrial metabolism in neurons. Hum Mol Genet 2018; 27:2187-2204. [PMID: 29648643 PMCID: PMC5985729 DOI: 10.1093/hmg/ddy127] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 03/27/2018] [Indexed: 12/30/2022] Open
Abstract
The nuclear-encoded glycyl-tRNA synthetase gene (GARS) is essential for protein translation in both cytoplasm and mitochondria. In contrast, different genes encode the mitochondrial and cytosolic forms of most other tRNA synthetases. Dominant GARS mutations were described in inherited neuropathies, while recessive mutations cause severe childhood-onset disorders affecting skeletal muscle and heart. The downstream events explaining tissue-specific phenotype-genotype relations remained unclear. We investigated the mitochondrial function of GARS in human cell lines and in the GarsC210R mouse model. Human-induced neuronal progenitor cells (iNPCs) carrying dominant and recessive GARS mutations showed alterations of mitochondrial proteins, which were more prominent in iNPCs with dominant, neuropathy-causing mutations. Although comparative proteomic analysis of iNPCs showed significant changes in mitochondrial respiratory chain complex subunits, assembly genes, Krebs cycle enzymes and transport proteins in both recessive and dominant mutations, proteins involved in fatty acid oxidation were only altered by recessive mutations causing mitochondrial cardiomyopathy. In contrast, significant alterations of the vesicle-associated membrane protein-associated protein B (VAPB) and its downstream pathways such as mitochondrial calcium uptake and autophagy were detected in dominant GARS mutations. The role of VAPB has been supported by similar results in the GarsC210R mice. Our data suggest that altered mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) may be important disease mechanisms leading to neuropathy in this condition.
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Affiliation(s)
- Veronika Boczonadi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
| | - Kathrin Meyer
- The Research Institute, Nationwide Children’s Hospital, Columbus, OH 43205, USA
| | - Humberto Gonczarowska-Jorge
- Leibniz-Institute für Analytische Wissenschaften-ISAS-e.V., Dortmund 44139, Germany,CAPES Foundation, Ministry of Education of Brazil, Brazil
| | - Helen Griffin
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
| | - Andreas Roos
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK,Leibniz-Institute für Analytische Wissenschaften-ISAS-e.V., Dortmund 44139, Germany
| | - Marina Bartsakoulia
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
| | - Boglarka Bansagi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
| | - Giulia Ricci
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK,Department of Clinical and Experimental Medicine, University of Pisa, Pisa 56126, Italy
| | - Fanni Palinkas
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
| | - René P Zahedi
- Leibniz-Institute für Analytische Wissenschaften-ISAS-e.V., Dortmund 44139, Germany
| | - Francesco Bruni
- Institute of Neuroscience, Wellcome Centre for Mitochondrial Research, Newcastle University, NE2 4HH Newcastle upon Tyne, UK,Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, 70121 Bari, Italy
| | - Brian Kaspar
- The Research Institute, Nationwide Children’s Hospital, Columbus, OH 43205, USA,Department of Neuroscience, Molecular, Cellular, and Developmental Biology Graduate Program and Integrated Biomedical Science Graduate Program, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Hanns Lochmüller
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK,Department of Neuropediatrics and Muscle Disorders, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg 79160, Germany,Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain
| | - Kym M Boycott
- Department of Genetics, CHEO Research Institute, University of Ottawa, K1H 8L1 Ottawa, Canada
| | - Juliane S Müller
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
| | - Rita Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK,To whom correspondence should be addressed at: Institute of Genetic Medicine, Newcastle University, Central Parkway, NE1 3BZ Newcastle upon Tyne, UK. Tel: +44 1912418855; Fax: +44 1912418666;
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Grice SJ, Sleigh JN, Zameel Cader M. Plexin-Semaphorin Signaling Modifies Neuromuscular Defects in a Drosophila Model of Peripheral Neuropathy. Front Mol Neurosci 2018. [PMID: 29520219 PMCID: PMC5827687 DOI: 10.3389/fnmol.2018.00055] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Dominant mutations in GARS, encoding the ubiquitous enzyme glycyl-tRNA synthetase (GlyRS), cause peripheral nerve degeneration and Charcot-Marie-Tooth disease type 2D (CMT2D). This genetic disorder exemplifies a recurring paradigm in neurodegeneration, in which mutations in essential genes cause selective degeneration of the nervous system. Recent evidence suggests that the mechanism underlying CMT2D involves extracellular neomorphic binding of mutant GlyRS to neuronally-expressed proteins. Consistent with this, our previous studies indicate a non-cell autonomous mechanism, whereby mutant GlyRS is secreted and interacts with the neuromuscular junction (NMJ). In this Drosophila model for CMT2D, we have previously shown that mutant gars expression decreases viability and larval motor function, and causes a concurrent build-up of mutant GlyRS at the larval neuromuscular presynapse. Here, we report additional phenotypes that closely mimic the axonal branching defects of Drosophila plexin transmembrane receptor mutants, implying interference of plexin signaling in gars mutants. Individual dosage reduction of two Drosophila Plexins, plexin A (plexA) and B (plexB) enhances and represses the viability and larval motor defects caused by mutant GlyRS, respectively. However, we find plexB levels, but not plexA levels, modify mutant GlyRS association with the presynaptic membrane. Furthermore, increasing availability of the plexB ligand, Semaphorin-2a (Sema2a), alleviates the pathology and the build-up of mutant GlyRS, suggesting competition for plexB binding may be occurring between these two ligands. This toxic gain-of-function and subversion of neurodevelopmental processes indicate that signaling pathways governing axonal guidance could be integral to neuropathology and may underlie the non-cell autonomous CMT2D mechanism.
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Affiliation(s)
- Stuart J Grice
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - M Zameel Cader
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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Boczonadi V, Jennings MJ, Horvath R. The role of tRNA synthetases in neurological and neuromuscular disorders. FEBS Lett 2018; 592:703-717. [PMID: 29288497 PMCID: PMC5873386 DOI: 10.1002/1873-3468.12962] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/06/2017] [Accepted: 12/21/2017] [Indexed: 12/11/2022]
Abstract
Aminoacyl‐tRNA synthetases (ARSs) are ubiquitously expressed enzymes responsible for charging tRNAs with their cognate amino acids, therefore essential for the first step in protein synthesis. Although the majority of protein synthesis happens in the cytosol, an additional translation apparatus is required to translate the 13 mitochondrial DNA‐encoded proteins important for oxidative phosphorylation. Most ARS genes in these cellular compartments are distinct, but two genes are common, encoding aminoacyl‐tRNA synthetases of glycine (GARS) and lysine (KARS) in both mitochondria and the cytosol. Mutations in the majority of the 37 nuclear‐encoded human ARS genes have been linked to a variety of recessive and dominant tissue‐specific disorders. Current data indicate that impaired enzyme function could explain the pathogenicity, however not all pathogenic ARSs mutations result in deficient catalytic function; thus, the consequences of mutations may arise from other molecular mechanisms. The peripheral nerves are frequently affected, as illustrated by the high number of mutations in cytosolic and bifunctional tRNA synthetases causing Charcot–Marie–Tooth disease (CMT). Here we provide insights on the pathomechanisms of CMT‐causing tRNA synthetases with specific focus on the two bifunctional tRNA synthetases (GARS, KARS).
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Affiliation(s)
- Veronika Boczonadi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Matthew J Jennings
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Rita Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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Presynaptic Deficits at Neuromuscular Junctions: A Specific Cause and Potential Target of Axonal Neuropathy in Type 2 Charcot-Marie-Tooth Disease. J Neurosci 2018; 36:8067-9. [PMID: 27488627 DOI: 10.1523/jneurosci.1515-16.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/23/2016] [Indexed: 11/21/2022] Open
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Abstract
PURPOSE OF REVIEW Charcot-Marie-Tooth disease (CMT) is one of the commonest inherited neuromuscular diseases with a population prevalence of 1 in 2500. This review will cover recent advances in the genetics and pathomechanisms of CMT and how these are leading to the development of rational therapies. RECENT FINDINGS Pathomechanistic and therapeutic target advances in CMT include the identification of the ErbB receptor signalling pathway as a therapeutic target in CMT1A and pharmacological modification of the unfolded protein response in CMT1B. In CMT2D, due to mutations in glycyl-tRNA synthetase, vascular endothelial growth factor-mediated stimulation of the Nrp1 receptor has been identified as a therapeutic target. Preclinical advances have been accompanied by the publication of large natural history cohorts and the identification of a sensitive biomarker of disease (muscle MRI) that is able to detect disease progression in CMT1A over 1 year. SUMMARY Advances in next-generation sequencing technology, cell biology and animal models of CMT are paving the way for rational treatments. The combination of robust natural history data and the identification of sensitive biomarkers mean that we are now entering an exciting therapeutic era in the field of the genetic neuropathies.
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Soliman E, Bianchi F, Sleigh JN, George JH, Cader MZ, Cui Z, Ye H. Engineered method for directional growth of muscle sheets on electrospun fibers. J Biomed Mater Res A 2018; 106:1165-1176. [PMID: 29266766 DOI: 10.1002/jbm.a.36312] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/22/2017] [Accepted: 12/15/2017] [Indexed: 12/11/2022]
Abstract
Research on the neuromuscular junction (NMJ) and its function and development spans over a century. However, researchers are limited in their ability to conduct experimentation on this highly specialized synapse between motor neurons and muscle fibers, as NMJs are not easily accessible outside the body. The aim of this work is to provide a reliable and reproducible muscle sheet model for in vitro NMJ study. A novel culture system was designed by engineering a method for the directional growth of myofiber sheets, using muscle progenitor cells cultured on electrospun fiber networks. Myoblastic C2C12 cells cultured on suspended aligned fibers were found to maintain directionality, with alignment angle standard deviations approximately two-thirds lower on fibers than on regular culture surfaces. Morphological studies found nuclei and cytoskeleton aspect ratios to be elongated by 20 and 150%, respectively. Furthermore, neurons were shown to form innervation patterns parallel to suspended fibers when co-cultured on developed muscle sheets, with alignment angle standard deviations three times lower compared with those on typical surfaces. The effect of agrin on samples was quantified through the slow release of agrin medium, encapsulated in alginate pellets and imbedded within culture chambers. Samples exposed to agrin showed significantly increased percentage of AChR-covered area. The developed model has potential to serve as the basis for synaptogenesis and NMJ studies, providing a novel approach to bio-artificial muscle alignment and setting the groundwork for further investigations in innervation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1165-1176, 2018.
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Affiliation(s)
- Erfan Soliman
- Department of Engineering Sciences, Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Fabio Bianchi
- Department of Engineering Sciences, Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - James N Sleigh
- Nuffield Department of Clinical Neurosciences, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital/Headley Way, Oxford, OX3 9DS, United Kingdom
| | - Julian H George
- Department of Engineering Sciences, Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - M Zameel Cader
- Nuffield Department of Clinical Neurosciences, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital/Headley Way, Oxford, OX3 9DS, United Kingdom
| | - Zhanfeng Cui
- Department of Engineering Sciences, Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Hua Ye
- Department of Engineering Sciences, Institute of Biomedical Engineering, Old Road Campus Research Building, University of Oxford, Oxford, OX3 7DQ, United Kingdom
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Morelli KH, Seburn KL, Schroeder DG, Spaulding EL, Dionne LA, Cox GA, Burgess RW. Severity of Demyelinating and Axonal Neuropathy Mouse Models Is Modified by Genes Affecting Structure and Function of Peripheral Nodes. Cell Rep 2017; 18:3178-3191. [PMID: 28355569 DOI: 10.1016/j.celrep.2017.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 11/11/2016] [Accepted: 03/01/2017] [Indexed: 12/22/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous group of inherited polyneuropathies. Mutations in 80 genetic loci can cause forms of CMT, resulting in demyelination and axonal dysfunction. The clinical presentation, including sensory deficits, distal muscle weakness, and atrophy, can vary greatly in severity and progression. Here, we used mouse models of CMT to demonstrate genetic interactions that result in a more severe neuropathy phenotype. The cell adhesion molecule Nrcam and the Na+ channel Scn8a (NaV1.6) are important components of nodes. Homozygous Nrcam and heterozygous Scn8a mutations synergized with both an Sh3tc2 mutation, modeling recessive demyelinating Charcot-Marie-Tooth type 4C, and mutations in Gars, modeling dominant axonal Charcot-Marie-Tooth type 2D. We conclude that genetic variants perturbing the structure and function of nodes interact with mutations affecting the cable properties of axons by thinning myelin or reducing axon diameter. Therefore, genes integral to peripheral nodes are candidate modifiers of peripheral neuropathy.
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Affiliation(s)
- Kathryn H Morelli
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | | | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | - Gregory A Cox
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA.
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Neuropilin 1 sequestration by neuropathogenic mutant glycyl-tRNA synthetase is permissive to vascular homeostasis. Sci Rep 2017; 7:9216. [PMID: 28835631 PMCID: PMC5569042 DOI: 10.1038/s41598-017-10005-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/27/2017] [Indexed: 12/11/2022] Open
Abstract
The mechanism by which dominantly inherited mutations in the housekeeping gene GARS, which encodes glycyl-tRNA synthetase (GlyRS), mediate selective peripheral nerve toxicity resulting in Charcot-Marie-Tooth disease type 2D (CMT2D) is still largely unresolved. The transmembrane receptor protein neuropilin 1 (Nrp1) was recently identified as an aberrant extracellular binding partner of mutant GlyRS. Formation of the Nrp1/mutant GlyRS complex antagonises Nrp1 interaction with one of its main natural ligands, vascular endothelial growth factor-A (VEGF-A), contributing to neurodegeneration. However, reduced extracellular binding of VEGF-A to Nrp1 is known to disrupt post-natal blood vessel development and growth. We therefore analysed the vascular system at early and late symptomatic time points in CMT2D mouse muscles, retina, and sciatic nerve, as well as in embryonic hindbrain. Mutant tissues show no difference in blood vessel diameter, density/growth, and branching from embryonic development to three months, spanning the duration over which numerous sensory and neuromuscular phenotypes manifest. Our findings indicate that mutant GlyRS-mediated disruption of Nrp1/VEGF-A signalling is permissive to maturation and maintenance of the vasculature in CMT2D mice.
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