1
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Drouyer M, Chu TH, Labit E, Haase F, Navarro RG, Nazareth D, Rosin N, Merjane J, Scott S, Cabanes-Creus M, Westhaus A, Zhu E, Midha R, Alexander IE, Biernaskie J, Ginn SL, Lisowski L. Novel AAV variants with improved tropism for human Schwann cells. Mol Ther Methods Clin Dev 2024; 32:101234. [PMID: 38558569 PMCID: PMC10978538 DOI: 10.1016/j.omtm.2024.101234] [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: 07/11/2023] [Accepted: 03/08/2024] [Indexed: 04/04/2024]
Abstract
Gene therapies and associated technologies are transforming biomedical research and enabling novel therapeutic options for patients living with debilitating and incurable genetic disorders. The vector system based on recombinant adeno-associated viral vectors (AAVs) has shown great promise in recent clinical trials for genetic diseases of multiple organs, such as the liver and the nervous system. Despite recent successes toward the development of novel bioengineered AAV variants for improved transduction of primary human tissues and cells, vectors that can efficiently transduce human Schwann cells (hSCs) have yet to be identified. Here, we report the application of the functional transduction-RNA selection method in primary hSCs for the development of AAV variants for specific and efficient transgene delivery to hSCs. The two identified capsid variants, Pep2hSC1 and Pep2hSC2, show conserved potency for delivery across various in vitro, in vivo, and ex vivo models of hSCs. These novel AAV capsids will serve as valuable research tools, forming the basis for therapeutic solutions for both SC-related disorders or peripheral nervous system injury.
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Affiliation(s)
- Matthieu Drouyer
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Tak-Ho Chu
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Elodie Labit
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Florencia Haase
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Renina Gale Navarro
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Deborah Nazareth
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Nicole Rosin
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Jessica Merjane
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Suzanne Scott
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Marti Cabanes-Creus
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Adrian Westhaus
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Erhua Zhu
- Gene Therapy Research Unit, Children’s Medical Research Institute and Sydney Children’s Hospitals Network, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Rajiv Midha
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Ian E. Alexander
- Gene Therapy Research Unit, Children’s Medical Research Institute and Sydney Children’s Hospitals Network, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Jeff Biernaskie
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
- Department of Surgery, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Samantha L. Ginn
- Gene Therapy Research Unit, Children’s Medical Research Institute and Sydney Children’s Hospitals Network, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
| | - Leszek Lisowski
- Translational Vectorology Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW, Australia
- Australian Genome Therapeutics Centre, Children’s Medical Research Institute and Sydney Children’s Hospitals Network, Westmead, NSW, Australia
- Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine - National Research Institute, Warsaw, Poland
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2
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Butler J, Dale N. X-linked Charcot Marie Tooth mutations alter CO 2 sensitivity of connexin32 hemichannels. Front Cell Neurosci 2023; 17:1330983. [PMID: 38188670 PMCID: PMC10771293 DOI: 10.3389/fncel.2023.1330983] [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: 10/31/2023] [Accepted: 12/07/2023] [Indexed: 01/09/2024] Open
Abstract
Connexin32 (Cx32) is expressed in myelinating Schwann cells. It forms both reflexive gap junctions, to facilitate transfer of molecules from the outer to the inner myelin layers and hemichannels at the paranode to permit action potential-evoked release of ATP into the extracellular space. Loss of function mutations in Cx32 cause X-linked Charcot Marie Tooth disease (CMTX), a slowly developing peripheral neuropathy. The mechanistic links between Cx32 mutations and CMTX are not well understood. As Cx32 hemichannels can be opened by increases in PCO2, we have examined whether CMTX mutations alter this CO2 sensitivity. By using Ca2+ imaging, dye loading and genetically encoded ATP sensors to measure ATP release, we have found 5 CMTX mutations that abolish the CO2 sensitivity of Cx32 hemichannels (A88D, 111-116 Del, C179Y, E102G, V139M). Others cause a partial loss (L56F, R220Stop, and R15W). Some CMTX mutations have no apparent effect on CO2 sensitivity (R15Q, L9F, G12S, V13L, V84I, W133R). The mutation R15W alters multiple additional aspects of hemichannel function including Ca2+ and ATP permeability. The mutations that abolish CO2 sensitivity are transdominant and abolish CO2 sensitivity of co-expressed Cx32WT. We have shown that Schwannoma RT4 D6P2T cells can release ATP in response to elevated PCO2 via the opening of Cx32. This is consistent with the hypothesis that the CO2 sensitivity of Cx32 may be important for maintenance of healthy myelin. Our data, showing a transdominant effect of certain CMTX mutations on CO2 sensitivity, may need to be taken into account in any future gene therapies for this condition.
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Affiliation(s)
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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3
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Georgiou E, Kagiava A, Sargiannidou I, Schiza N, Stavrou M, Richter J, Tryfonos C, Heslegrave A, Zetterberg H, Christodoulou C, Kleopa KA. AAV9-mediated SH3TC2 gene replacement therapy targeted to Schwann cells for the treatment of CMT4C. Mol Ther 2023; 31:3290-3307. [PMID: 37641403 PMCID: PMC10638072 DOI: 10.1016/j.ymthe.2023.08.020] [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: 02/14/2023] [Revised: 07/19/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023] Open
Abstract
Type 4C Charcot-Marie-Tooth (CMT4C) demyelinating neuropathy is caused by autosomal recessive SH3TC2 gene mutations. SH3TC2 is highly expressed in myelinating Schwann cells. CMT4C is a childhood-onset progressive disease without effective treatment. Here, we generated a gene therapy for CMT4C mediated by an adeno-associated viral 9 vector (AAV9) to deliver the human SH3TC2 gene in the Sh3tc2-/- mouse model of CMT4C. We used a minimal fragment of the myelin protein zero (Mpz) promoter (miniMpz), which was cloned and validated to achieve Schwann cell-targeted expression of SH3TC2. Following the demonstration of AAV9-miniMpz.SH3TC2myc vector efficacy to re-establish SH3TC2 expression in the peripheral nervous system, we performed an early as well as a delayed treatment trial in Sh3tc2-/- mice. We demonstrate both after early as well as following late treatment improvements in multiple motor performance tests and nerve conduction velocities. Moreover, treatment led to normalization of the organization of the nodes of Ranvier, which is typically deficient in CMT4C patients and Sh3tc2-/- mice, along with reduced ratios of demyelinated fibers, increased myelin thickness and reduced g-ratios at both time points of intervention. Taken together, our results provide a proof of concept for an effective and potentially translatable gene replacement therapy for CMT4C treatment.
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Affiliation(s)
- Elena Georgiou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Natasa Schiza
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Jan Richter
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Christina Tryfonos
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Amanda Heslegrave
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Henrik Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, London, UK; Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China; Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Christina Christodoulou
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus; Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.
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4
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Shen Z, Li M, He F, Huang C, Zheng Y, Wang Z, Ma S, Chen L, Liu Z, Zheng H, Xiong F. Intravenous Administration of an AAV9 Vector Ubiquitously Expressing C1orf194 Gene Improved CMT-Like Neuropathy in C1orf194 -/- Mice. Neurotherapeutics 2023; 20:1835-1846. [PMID: 37843769 PMCID: PMC10684460 DOI: 10.1007/s13311-023-01429-6] [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] [Accepted: 08/19/2023] [Indexed: 10/17/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) disease, also known as hereditary motor sensory neuropathy, is a group of rare genetically heterogenous diseases characterized by progressive muscle weakness and atrophy, along with sensory deficits. Despite extensive pre-clinical and clinical research, no FDA-approved therapy is available for any CMT type. We previously identified C1ORF194, a novel causative gene for CMT, and found that both C1orf194 knock-in (I121N) and knockout mice developed clinical phenotypes similar to those in patients with CMT. Encouraging results of adeno-associated virus (AAV)-mediated gene therapy for spinal muscular atrophy have stimulated the use of AAVs as vehicles for CMT gene therapy. Here, we present a gene therapy approach to restore C1orf194 expression in a knockout background. We used C1orf194-/- mice treated with AAV serotype 9 (AAV9) vector carrying a codon-optimized WT human C1ORF194 cDNA whose expression was driven by a ubiquitously expressed chicken β-actin promoter with a CMV enhancer. Our preclinical evaluation demonstrated the efficacy of AAV-mediated gene therapy in improving sensory and motor abilities, thus achieving largely normal gross motor performance and minimal signs of neuropathy, on the basis of neurophysiological and histopathological evaluation in C1orf194-/- mice administered AAV gene therapy. Our findings advance the techniques for delivering therapeutic interventions to individuals with CMT.
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Affiliation(s)
- Zongrui Shen
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Meiyi Li
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Fei He
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Cheng Huang
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yingchun Zheng
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhikui Wang
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Shunfei Ma
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Li Chen
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhengshan Liu
- Division of Translational Neuroscience in Schizophrenia, Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Hui Zheng
- Department of Neurology, The First School of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Fu Xiong
- Department of Medical Genetics, Experimental Education/Administration Center, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
- Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, Guangdong, China.
- Department of Fetal Medicine and Prenatal Diagnosis, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
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5
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Kagiava A, Karaiskos C, Lapathitis G, Heslegrave A, Sargiannidou I, Zetterberg H, Bosch A, Kleopa KA. Gene replacement therapy in two Golgi-retained CMT1X mutants before and after the onset of demyelinating neuropathy. Mol Ther Methods Clin Dev 2023; 30:377-393. [PMID: 37645436 PMCID: PMC10460951 DOI: 10.1016/j.omtm.2023.07.011] [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: 01/03/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023]
Abstract
X-linked Charcot-Marie-Tooth disease type 1 (CMT1X) is a demyelinating neuropathy resulting from loss-of-function mutations affecting the GJB1/connexin 32 (Cx32) gene. We previously showed functional and morphological improvement in Gjb1-null mice following AAV9-mediated delivery of human Cx32 driven by the myelin protein zero (Mpz) promoter in Schwann cells. However, CMT1X mutants may interfere with virally delivered wild-type (WT) Cx32. To confirm the efficacy of this vector also in the presence of CMT1X mutants, we delivered AAV9-Mpz-GJB1 by lumbar intrathecal injection in R75W/Gjb1-null and N175D/Gjb1-null transgenic lines expressing Golgi-retained mutations, before and after the onset of the neuropathy. Widespread expression of virally delivered Cx32 was demonstrated in both genotypes. Re-establishment of WT Cx32 function resulted in improved muscle strength and increased sciatic nerve motor conduction velocities in all treated groups from both mutant lines when treated before as well as after the onset of the neuropathy. Furthermore, morphological analysis showed improvement of myelination and reduction of inflammation in lumbar motor roots and peripheral nerves. In conclusion, this study provides proof of principle for a clinically translatable gene therapy approach to treat CMT1X before and after the onset of the neuropathy, even in the presence of endogenously expressed Golgi-retained Cx32 mutants.
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Affiliation(s)
- Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Christos Karaiskos
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - George Lapathitis
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Amanda Heslegrave
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Henrik Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, 40530 Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 40530 Mölndal, Sweden
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
- Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Assumpció Bosch
- Department of Biochemistry & Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193 Bellatera, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 028029 Madrid, Spain
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
- Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
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6
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Bhuiyan SA, Xu M, Yang L, Semizoglou E, Bhatia P, Pantaleo KI, Tochitsky I, Jain A, Erdogan B, Blair S, Cat V, Mwirigi JM, Sankaranarayanan I, Tavares-Ferreira D, Green U, McIlvried LA, Copits BA, Bertels Z, Del Rosario JS, Widman AJ, Slivicki RA, Yi J, Woolf CJ, Lennerz JK, Whited JL, Price TJ, Gereau RW, Renthal W. Harmonized cross-species cell atlases of trigeminal and dorsal root ganglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.04.547740. [PMID: 37461736 PMCID: PMC10350076 DOI: 10.1101/2023.07.04.547740] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Peripheral sensory neurons in the dorsal root ganglion (DRG) and trigeminal ganglion (TG) are specialized to detect and transduce diverse environmental stimuli including touch, temperature, and pain to the central nervous system. Recent advances in single-cell RNA-sequencing (scRNA-seq) have provided new insights into the diversity of sensory ganglia cell types in rodents, non-human primates, and humans, but it remains difficult to compare transcriptomically defined cell types across studies and species. Here, we built cross-species harmonized atlases of DRG and TG cell types that describe 18 neuronal and 11 non-neuronal cell types across 6 species and 19 studies. We then demonstrate the utility of this harmonized reference atlas by using it to annotate newly profiled DRG nuclei/cells from both human and the highly regenerative axolotl. We observe that the transcriptomic profiles of sensory neuron subtypes are broadly similar across vertebrates, but the expression of functionally important neuropeptides and channels can vary notably. The new resources and data presented here can guide future studies in comparative transcriptomics, simplify cell type nomenclature differences across studies, and help prioritize targets for future pain therapy development.
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Affiliation(s)
- Shamsuddin A Bhuiyan
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Mengyi Xu
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Alan Edwards Center for Research on Pain and Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Lite Yang
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Evangelia Semizoglou
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Parth Bhatia
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Katerina I Pantaleo
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ivan Tochitsky
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir. Boston, MA 02115
| | - Aakanksha Jain
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir. Boston, MA 02115
| | - Burcu Erdogan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Steven Blair
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Victor Cat
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Juliet M Mwirigi
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Diana Tavares-Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Ursula Green
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114
| | - Lisa A McIlvried
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Bryan A Copits
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Zachariah Bertels
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - John S Del Rosario
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Allie J Widman
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Richard A Slivicki
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Jiwon Yi
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir. Boston, MA 02115
| | - Jochen K Lennerz
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114
| | - Jessica L Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Robert W Gereau
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - William Renthal
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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7
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Dale N, Butler J, Dospinescu VM, Nijjar S. Channel-mediated ATP release in the nervous system. Neuropharmacology 2023; 227:109435. [PMID: 36690324 DOI: 10.1016/j.neuropharm.2023.109435] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/10/2023] [Accepted: 01/19/2023] [Indexed: 01/21/2023]
Abstract
ATP is well established as a transmitter and modulator in the peripheral and central nervous system. While conventional exocytotic release of ATP at synapses occurs, this transmitter is unusual in also being released into the extracellular space via large-pored plasma membrane channels. This review considers the channels that are known to be permeable to ATP and some of the functions of channel-mediated ATP release. While the possibility of ATP release via channels mediating volume transmission has been known for some time, localised ATP release via channels at specialised synapses made by taste cells to the afferent nerve has recently been documented in taste buds. This raises the prospect that "channel synapses" may occur in other contexts. However, volume transmission and channel synapses are not necessarily mutually exclusive. We suggest that certain glial cells in the brain stem and hypothalamus, which possess long processes and are known to release ATP, may be candidates for both modes of ATP release -channel-mediated volume transmission in the region of their somata and more localised transmission possibly via either conventional or channel synapses from their processes at distal targets. Finally, we consider the different characteristics of vesicular and channel synapses and suggest that channel synapses may be advantageous in requiring less energy than their conventional vesicular counterparts. This article is part of the Special Issue on "Purinergic Signaling: 50 years".
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Affiliation(s)
- Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, CV4, AL, UK.
| | - Jack Butler
- School of Life Sciences, University of Warwick, Coventry, CV4, AL, UK
| | | | - Sarbjit Nijjar
- School of Life Sciences, University of Warwick, Coventry, CV4, AL, UK
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8
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Kaur S, Zhang X, Patel S, Rodriguez YA, Luther KJ, Alghafli G, Lang RM, Abrams CK, Dobrowsky RT. Pharmacologic Targeting of the C-Terminus of Heat Shock Protein 90 Improves Neuromuscular Function in Animal Models of Charcot Marie Tooth X1 Disease. ACS Pharmacol Transl Sci 2023; 6:306-319. [PMID: 36798471 PMCID: PMC9926526 DOI: 10.1021/acsptsci.2c00223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Indexed: 01/22/2023]
Abstract
Charcot-Marie-Tooth X1 (CMTX1) disease is an inherited peripheral neuropathy that arises from loss-of-function mutations in the protein connexin 32 (Cx32). CMTX1 currently lacks a pharmacologic approach toward disease management, and we have previously shown that modulating the expression of molecular chaperones using novologue therapy may provide a viable disease-modifying approach to treat metabolic and demyelinating neuropathies. Cemdomespib is an orally bioavailable novologue that manifests neuroprotective activity by modulating the expression of heat shock protein 70 (Hsp70). We examined if 1 to 5 months of daily cemdomespib therapy may improve neuropathic symptoms in three mouse models of CMTX1 (Cx32 deficient (Cx32def), T55I-Cx32def, and R75W-Cx32 mice). Daily drug therapy significantly improved motor nerve conduction velocity (MNCV) and grip strength in all three models, but the compound muscle action potential was only improved in Cx32def mice. Drug efficacy required Hsp70 as improvements in MNCV, and the grip strength was abrogated in Cx32def × Hsp70 knockout mice. Five months of novologue therapy was associated with improved neuromuscular junction morphology, femoral motor nerve myelination, reduction in foamy macrophages, and a decrease in Schwann cell c-jun levels. To determine if c-jun may be downstream of Hsp70 and necessary for drug efficacy, c-jun expression was specifically deleted in Schwann cells of Cx32def mice. While the deletion of c-jun worsened the neuropathy, cemdomespib therapy remained effective in improving MNCV and grip strength. Our data show that cemdomespib therapy improves CMTX1-linked neuropathy in an Hsp70-dependent but a c-jun-independent manner and without regard to the nature of the underlying Cx32 mutation.
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Affiliation(s)
- Sukhmanjit Kaur
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Xinyue Zhang
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Sugandha Patel
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Yssa A. Rodriguez
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Kylie J. Luther
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Ghufran Alghafli
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Ryan M. Lang
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
| | - Charles K. Abrams
- Department
of Neurology and Rehabilitation and Biomedical Engineering, College
of Medicine, University of Illinois Chicago, Chicago, Illinois 60612, United States
| | - Rick T. Dobrowsky
- Department
of Pharmacology and Toxicology, University
of Kansas, Lawrence, Kansas 66045, United States
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9
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Abrams CK, Lancaster E, Li JJ, Dungan G, Gong D, Scherer SS, Freidin MM. Knock-in mouse models for CMTX1 show a loss of function phenotype in the peripheral nervous system. Exp Neurol 2023; 360:114277. [PMID: 36403785 DOI: 10.1016/j.expneurol.2022.114277] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/28/2022] [Accepted: 11/16/2022] [Indexed: 11/20/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMTX1) is the second most common form of CMT. In this study we used CRISPR/Cas9 to develop new "knock-in" models of CMTX1 that are more representative of the spectrum of mutations seen with CMTX1 than the Cx32 knockout (KO) mouse model used previously. We compared mice of four genotypes - wild-type, Cx32KO, p.T55I, and p.R75W. Sciatic motor conduction velocity slowing was the most robust electrophysiologic indicator of neuropathy, showing reductions in the Cx32KO by 3 months and in the p.T55I and p.R75W mice by 6 months. At both 6 and 12 months, all three mutant genotypes showed reduced four limb and hind limb grip strength compared to WT mice. Performance on 6 and 12 mm width balance beams revealed deficits that were most pronounced at on the 6 mm balance beam at 6 months of age. There were pathological changes of myelinated axons in the femoral motor nerve in all three mutant lines by 3 months of age, and these became more pronounced at 6 and 12 months of age; sensory nerves (femoral sensory and the caudal nerve of the tail) appeared normal at all ages examined. Our results demonstrate that mice can be used to show the pathogenicity of human GJB1 mutations, and these new models for CMTX1 should facilitate the preclinical work for developing treatments for CMTX1.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, 912 South Wood Street, Chicago, IL 60657, USA; Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, USA.
| | - Eunjoo Lancaster
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA..
| | - Jian J Li
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA..
| | - Gabriel Dungan
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, 912 South Wood Street, Chicago, IL 60657, USA
| | - David Gong
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, USA.
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA..
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, 912 South Wood Street, Chicago, IL 60657, USA.
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10
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Hines TJ, Tadenev ALD, Lone MA, Hatton CL, Bagasrawala I, Stum MG, Miers KE, Hornemann T, Burgess RW. Precision mouse models of Yars/dominant intermediate Charcot-Marie-Tooth disease type C and Sptlc1/hereditary sensory and autonomic neuropathy type 1. J Anat 2022; 241:1169-1185. [PMID: 34875719 PMCID: PMC9170831 DOI: 10.1111/joa.13605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 01/25/2023] Open
Abstract
Animal models of neurodegenerative diseases such as inherited peripheral neuropathies sometimes accurately recreate the pathophysiology of the human disease, and sometimes accurately recreate the genetic perturbations found in patients. Ideally, models achieve both, but this is not always possible; nonetheless, such models are informative. Here we describe two animal models of inherited peripheral neuropathy: mice with a mutation in tyrosyl tRNA-synthetase, YarsE196K , modeling dominant intermediate Charcot-Marie-Tooth disease type C (diCMTC), and mice with a mutation in serine palmitoyltransferase long chain 1, Sptlc1C133W , modeling hereditary sensory and autonomic neuropathy type 1 (HSAN1). YarsE196K mice develop disease-relevant phenotypes including reduced motor performance and reduced nerve conduction velocities by 4 months of age. Peripheral motor axons are reduced in size, but there is no reduction in axon number and plasma neurofilament light chain levels are not increased. Unlike the dominant human mutations, the YarsE196K mice only show these phenotypes as homozygotes, or as compound heterozygotes with a null allele, and no phenotype is observed in E196K or null heterozygotes. The Sptlc1C133W mice carry a knockin allele and show the anticipated increase in 1-deoxysphingolipids in circulation and in a variety of tissues. They also have mild behavioral defects consistent with HSAN1, but do not show neurophysiological defects or axon loss in peripheral nerves or in the epidermis of the hind paw or tail. Thus, despite the biochemical phenotype, the Sptlc1C133W mice do not show a strong neuropathy phenotype. Surprisingly, these mice were lethal as homozygotes, but the heterozygous genotype studied corresponds to the dominant genetics seen in humans. Thus, YarsE196K homozygous mice have a relevant phenotype, but imprecisely reproduce the human genetics, whereas the Sptlc1C133W mice precisely reproduce the human genetics, but do not recreate the disease phenotype. Despite these shortcomings, both models are informative and will be useful for future research.
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Affiliation(s)
| | | | - Museer A Lone
- Institute for Clinical Chemistry, University of Zurich, Zurich, Switzerland
| | | | | | | | | | - Thorsten Hornemann
- Institute for Clinical Chemistry, University of Zurich, Zurich, Switzerland
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11
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Kagiava A, Richter J, Tryfonos C, Leal-Julià M, Sargiannidou I, Christodoulou C, Bosch A, Kleopa KA. Efficacy of AAV serotypes to target Schwann cells after intrathecal and intravenous delivery. Sci Rep 2021; 11:23358. [PMID: 34857831 PMCID: PMC8640002 DOI: 10.1038/s41598-021-02694-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/18/2021] [Indexed: 12/20/2022] Open
Abstract
To optimize gene delivery to myelinating Schwann cells we compared clinically relevant AAV serotypes and injection routes. AAV9 and AAVrh10 vectors expressing either EGFP or the neuropathy-associated gene GJB1/Connexin32 (Cx32) under a myelin specific promoter were injected intrathecally or intravenously in wild type and Gjb1-null mice, respectively. Vector biodistribution in lumbar roots and sciatic nerves was higher in AAVrh10 injected mice while EGFP and Cx32 expression rates and levels were similar between the two serotypes. A gradient of biodistribution away from the injection site was seen with both intrathecal and intravenous delivery, while similar expression rates were achieved despite higher vector amounts injected intravenously. Quantified immune cells in relevant tissues were similar to non-injected littermates. Overall, AAV9 and AAVrh10 efficiently transduce Schwann cells throughout the peripheral nervous system with both clinically relevant routes of administration, although AAV9 and intrathecal injection may offer a more efficient approach for treating demyelinating neuropathies.
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Affiliation(s)
- A Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 Iroon Avenue, P.O. Box 23462, 1683, Nicosia, Cyprus.
| | - J Richter
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Tryfonos
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - M Leal-Julià
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Barcelona, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - I Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 Iroon Avenue, P.O. Box 23462, 1683, Nicosia, Cyprus
| | - C Christodoulou
- Molecular Virology Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A Bosch
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - K A Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 Iroon Avenue, P.O. Box 23462, 1683, Nicosia, Cyprus
- Center for Neuromuscular Diseases, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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12
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Schwann cell gene therapies in sight. Gene Ther 2021; 28:618-619. [PMID: 34099894 PMCID: PMC8602750 DOI: 10.1038/s41434-021-00264-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/11/2021] [Accepted: 05/19/2021] [Indexed: 01/30/2023]
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13
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Rawat A, Morrison BM. Metabolic Transporters in the Peripheral Nerve-What, Where, and Why? Neurotherapeutics 2021; 18:2185-2199. [PMID: 34773210 PMCID: PMC8804006 DOI: 10.1007/s13311-021-01150-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2021] [Indexed: 12/18/2022] Open
Abstract
Cellular metabolism is critical not only for cell survival, but also for cell fate, function, and intercellular communication. There are several different metabolic transporters expressed in the peripheral nervous system, and they each play important roles in maintaining cellular energy. The major source of energy in the peripheral nervous system is glucose, and glucose transporters 1 and 3 are expressed and allow blood glucose to be imported and utilized by peripheral nerves. There is also increasing evidence that other sources of energy, particularly monocarboxylates such as lactate that are transported primarily by monocarboxylate transporters 1 and 2 in peripheral nerves, can be efficiently utilized by peripheral nerves. Finally, emerging evidence supports an important role for connexins and possibly pannexins in the supply and regulation of metabolic energy. In this review, we will first define these critical metabolic transporter subtypes and then examine their localization in the peripheral nervous system. We will subsequently discuss the evidence, which comes both from experiments in animal models and observations from human diseases, supporting critical roles played by these metabolic transporters in the peripheral nervous system. Despite progress made in understanding the function of these transporters, many questions and some discrepancies remain, and these will also be addressed throughout this review. Peripheral nerve metabolism is fundamentally important and renewed interest in these pathways should help to answer many of these questions and potentially provide new treatments for neurologic diseases that are partly, or completely, caused by disruption of metabolism.
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Affiliation(s)
- Atul Rawat
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Brett M Morrison
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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14
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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: 51] [Impact Index Per Article: 17.0] [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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15
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Zuko A, Mallik M, Thompson R, Spaulding EL, Wienand AR, Been M, Tadenev ALD, van Bakel N, Sijlmans C, Santos LA, Bussmann J, Catinozzi M, Das S, Kulshrestha D, Burgess RW, Ignatova Z, Storkebaum E. tRNA overexpression rescues peripheral neuropathy caused by mutations in tRNA synthetase. Science 2021; 373:1161-1166. [PMID: 34516840 DOI: 10.1126/science.abb3356] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Amila Zuko
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Moushami Mallik
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Robin Thompson
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Anne R Wienand
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Marije Been
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | | | - Nick van Bakel
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Céline Sijlmans
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Leonardo A Santos
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Julia Bussmann
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Marica Catinozzi
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Sarada Das
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Divita Kulshrestha
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Zoya Ignatova
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Erik Storkebaum
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
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16
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Stavrou M, Sargiannidou I, Georgiou E, Kagiava A, Kleopa KA. Emerging Therapies for Charcot-Marie-Tooth Inherited Neuropathies. Int J Mol Sci 2021; 22:6048. [PMID: 34205075 PMCID: PMC8199910 DOI: 10.3390/ijms22116048] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/29/2021] [Accepted: 05/31/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited neuropathies known as Charcot-Marie-Tooth (CMT) disease are genetically heterogeneous disorders affecting the peripheral nerves, causing significant and slowly progressive disability over the lifespan. The discovery of their diverse molecular genetic mechanisms over the past three decades has provided the basis for developing a wide range of therapeutics, leading to an exciting era of finding treatments for this, until now, incurable group of diseases. Many treatment approaches, including gene silencing and gene replacement therapies, as well as small molecule treatments are currently in preclinical testing while several have also reached clinical trial stage. Some of the treatment approaches are disease-specific targeted to the unique disease mechanism of each CMT form, while other therapeutics target common pathways shared by several or all CMT types. As promising treatments reach the stage of clinical translation, optimal outcome measures, novel biomarkers and appropriate trial designs are crucial in order to facilitate successful testing and validation of novel treatments for CMT patients.
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Affiliation(s)
- Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Elena Georgiou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
- Center for Neuromuscular Diseases, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus
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17
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AAV9-mediated Schwann cell-targeted gene therapy rescues a model of demyelinating neuropathy. Gene Ther 2021; 28:659-675. [PMID: 33692503 PMCID: PMC8599011 DOI: 10.1038/s41434-021-00250-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 01/31/2023]
Abstract
Mutations in the GJB1 gene, encoding the gap junction (GJ) protein connexin32 (Cx32), cause X-linked Charcot-Marie-Tooth disease (CMT1X), an inherited demyelinating neuropathy. We developed a gene therapy approach for CMT1X using an AAV9 vector to deliver the GJB1/Cx32 gene under the myelin protein zero (Mpz) promoter for targeted expression in Schwann cells. Lumbar intrathecal injection of the AAV9-Mpz.GJB1 resulted in widespread biodistribution in the peripheral nervous system including lumbar roots, sciatic and femoral nerves, as well as in Cx32 expression in the paranodal non-compact myelin areas of myelinated fibers. A pre-, as well as post-onset treatment trial in Gjb1-null mice, demonstrated improved motor performance and sciatic nerve conduction velocities along with improved myelination and reduced inflammation in peripheral nerve tissues. Blood biomarker levels were also significantly ameliorated in treated mice. This study provides evidence that a clinically translatable AAV9-mediated gene therapy approach targeting Schwann cells could potentially treat CMT1X.
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18
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Genetic mechanisms of peripheral nerve disease. Neurosci Lett 2020; 742:135357. [PMID: 33249104 DOI: 10.1016/j.neulet.2020.135357] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022]
Abstract
Peripheral neuropathies of genetic etiology are a very diverse group of disorders manifesting either as non-syndromic inherited neuropathies without significant manifestations outside the peripheral nervous system, or as part of a systemic or syndromic genetic disorder. The former and most frequent group is collectively known as Charcot-Marie-Tooth disease (CMT), with prevalence as high as 1:2,500 world-wide, and has proven to be genetically highly heterogeneous. More than 100 different genes have been identified so far to cause various CMT forms, following all possible inheritance patterns. CMT causative genes belong to several common functional pathways that are essential for the integrity of the peripheral nerve. Their discovery has provided insights into the normal biology of axons and myelinating cells, and has highlighted the molecular mechanisms including both loss of function and gain of function effects, leading to peripheral nerve degeneration. Demyelinating neuropathies result from dysfunction of genes primarily affecting myelinating Schwann cells, while axonal neuropathies are caused by genes affecting mostly neurons and their long axons. Furthermore, mutation in genes expressed outside the nervous system, as in the case of inherited amyloid neuropathies, may cause peripheral neuropathy resulting from accumulation of β-structured amyloid fibrils in peripheral nerves in addition to various organs. Increasing insights into the molecular-genetic mechanisms have revealed potential therapeutic targets. These will enable the development of novel therapeutics for genetic neuropathies that remain, in their majority, without effective treatment.
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19
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Papaneophytou C, Georgiou E, Kleopa KA. The role of oligodendrocyte gap junctions in neuroinflammation. Channels (Austin) 2020; 13:247-263. [PMID: 31232168 PMCID: PMC6602578 DOI: 10.1080/19336950.2019.1631107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Gap junctions (GJs) provide channels for direct cell-to-cell connectivity serving the homeostasis in several organs of vertebrates including the central (CNS) and peripheral (PNS) nervous systems. GJs are composed of connexins (Cx), which show a highly distinct cellular and subcellular expression pattern. Oligodendrocytes, the myelinating cells of the CNS, are characterized by extensive GJ connectivity with each other as well as with astrocytes. The main oligodendrocyte connexins forming these GJ channels are Cx47 and Cx32. The importance of these channels has been highlighted by the discovery of human diseases caused by mutations in oligodendrocyte connexins, manifesting with leukodystrophy or transient encephalopathy. Experimental models have provided further evidence that oligodendrocyte GJs are essential for CNS myelination and homeostasis, while a strong inflammatory component has been recognized in the absence of oligodendrocyte connexins. Further studies revealed that connexins are also disrupted in multiple sclerosis (MS) brain, and in experimental models of induced inflammatory demyelination. Moreover, induced demyelination was more severe and associated with higher degree of CNS inflammation in models with oligodendrocyte GJ deficiency, suggesting that disrupted connexin expression in oligodendrocytes is not only a consequence but can also drive a pro-inflammatory environment in acquired demyelinating disorders such as MS. In this review, we summarize the current insights from human disorders as well as from genetic and acquired models of demyelination related to oligodendrocyte connexins, with the remaining challenges and perspectives.
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Affiliation(s)
- Christos Papaneophytou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,b Department of Life and Health Sciences, School of Sciences and Engineering , University of Nicosia , Nicosia , Cyprus
| | - Elena Georgiou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus
| | - Kleopas A Kleopa
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,c Neurology Clinics , the Cyprus Institute of Neurology and Genetics, and the Cyprus School of Molecular Medicine , Nicosia , Cyprus
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20
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Rzepnikowska W, Kaminska J, Kabzińska D, Binięda K, Kochański A. A Yeast-Based Model for Hereditary Motor and Sensory Neuropathies: A Simple System for Complex, Heterogeneous Diseases. Int J Mol Sci 2020; 21:ijms21124277. [PMID: 32560077 PMCID: PMC7352270 DOI: 10.3390/ijms21124277] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 12/13/2022] Open
Abstract
Charcot–Marie–Tooth (CMT) disease encompasses a group of rare disorders that are characterized by similar clinical manifestations and a high genetic heterogeneity. Such excessive diversity presents many problems. Firstly, it makes a proper genetic diagnosis much more difficult and, even when using the most advanced tools, does not guarantee that the cause of the disease will be revealed. Secondly, the molecular mechanisms underlying the observed symptoms are extremely diverse and are probably different for most of the disease subtypes. Finally, there is no possibility of finding one efficient cure for all, or even the majority of CMT diseases. Every subtype of CMT needs an individual approach backed up by its own research field. Thus, it is little surprise that our knowledge of CMT disease as a whole is selective and therapeutic approaches are limited. There is an urgent need to develop new CMT models to fill the gaps. In this review, we discuss the advantages and disadvantages of yeast as a model system in which to study CMT diseases. We show how this single-cell organism may be used to discriminate between pathogenic variants, to uncover the mechanism of pathogenesis, and to discover new therapies for CMT disease.
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Affiliation(s)
- Weronika Rzepnikowska
- Neuromuscular Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, 02-106 Warsaw, Poland; (W.R.); (D.K.); (K.B.)
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Dagmara Kabzińska
- Neuromuscular Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, 02-106 Warsaw, Poland; (W.R.); (D.K.); (K.B.)
| | - Katarzyna Binięda
- Neuromuscular Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, 02-106 Warsaw, Poland; (W.R.); (D.K.); (K.B.)
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Centre Polish Academy of Sciences, 02-106 Warsaw, Poland; (W.R.); (D.K.); (K.B.)
- Correspondence:
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21
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Xia CY, Xu JK, Pan CH, Lian WW, Yan Y, Ma BZ, He J, Zhang WK. Connexins in oligodendrocytes and astrocytes: Possible factors for demyelination in multiple sclerosis. Neurochem Int 2020; 136:104731. [PMID: 32201280 DOI: 10.1016/j.neuint.2020.104731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Increasing evidences support that glial connexins are involved in the demyelination pathology of multiple sclerosis (MS), a chronic inflammatory demyelinating disorder. Here, we review the data from patients with MS and animal models of MS that implicate connexins in demyelination. Connexins expressed in oligodendrocytes and astrocytes show diverse changes at the different phases of MS. Loss of oligodendrocyte or astrocyte connexins contributes to demyelination and exaggerates the pathology of MS. Channel-dependent and -independent connexins are involved in the pathology of demyelination, which is related with myelin integrity, metabolic homeostasis, the brain-blood barrier, the immune cell infiltration, and the inflammatory response. A comprehensive understanding of connexin function in demyelination may provide new therapeutic targets for MS.
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Affiliation(s)
- Cong-Yuan Xia
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Jie-Kun Xu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, People's Republic of China
| | - Chen-Hao Pan
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, People's Republic of China
| | - Wen-Wen Lian
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Yu Yan
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Bing-Zhi Ma
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Jun He
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
| | - Wei-Ku Zhang
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
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22
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Sargiannidou I, Kagiava A, Kleopa KA. Gene therapy approaches targeting Schwann cells for demyelinating neuropathies. Brain Res 2020; 1728:146572. [PMID: 31790684 DOI: 10.1016/j.brainres.2019.146572] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/12/2019] [Accepted: 11/26/2019] [Indexed: 11/27/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) encompasses numerous genetically heterogeneous inherited neuropathies, which together are one of the commonest neurogenetic disorders. Axonal CMT types result from mutations in neuronally expressed genes, whereas demyelinating CMT forms mostly result from mutations in genes expressed by myelinating Schwann cells. The demyelinating forms are the most common, and may be caused by dominant mutations and gene dosage effects (as in CMT1), as well as by recessive mutations and loss of function mechanisms (as in CMT4). The discovery of causative genes and increasing insights into molecular mechanisms through the study of experimental disease models has provided the basis for the development of gene therapy approaches. For demyelinating CMT, gene silencing or gene replacement strategies need to be targeted to Schwann cells. Progress in gene replacement for two different CMT forms, including CMT1X caused by GJB1 gene mutations, and CMT4C, caused by SH3TC2 gene mutations, has been made through the use of a myelin-specific promoter to restrict expression in Schwann cells, and by lumbar intrathecal delivery of lentiviral viral vectors to achieve more widespread biodistribution in the peripheral nervous system. This review summarizes the molecular-genetic mechanisms of selected demyelinating CMT neuropathies and the progress made so far, as well as the remaining challenges in the path towards a gene therapy to treat these disorders through the use of optimal gene therapy tools including clinically translatable delivery methods and adeno-associated viral (AAV) vectors.
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Affiliation(s)
- Irene Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus; Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
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23
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Kagiava A, Richter J, Tryfonos C, Karaiskos C, Heslegrave AJ, Sargiannidou I, Rossor AM, Zetterberg H, Reilly MM, Christodoulou C, Kleopa KA. Gene replacement therapy after neuropathy onset provides therapeutic benefit in a model of CMT1X. Hum Mol Genet 2019; 28:3528-3542. [PMID: 31411673 DOI: 10.1093/hmg/ddz199] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 12/22/2022] Open
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X), one of the commonest forms of inherited demyelinating neuropathy, results from GJB1 gene mutations causing loss of function of the gap junction protein connexin32 (Cx32). The aim of this study was to examine whether delayed gene replacement therapy after the onset of peripheral neuropathy can provide a therapeutic benefit in the Gjb1-null/Cx32 knockout model of CMT1X. After delivery of the LV-Mpz.GJB1 lentiviral vector by a single lumbar intrathecal injection into 6-month-old Gjb1-null mice, we confirmed expression of Cx32 in lumbar roots and sciatic nerves correctly localized at the paranodal myelin areas. Gjb1-null mice treated with LV-Mpz.GJB1 compared with LV-Mpz.Egfp (mock) vector at the age of 6 months showed improved motor performance at 8 and 10 months. Furthermore, treated mice showed increased sciatic nerve conduction velocities, improvement of myelination and reduced inflammation in lumbar roots and peripheral nerves at 10 months of age, along with enhanced quadriceps muscle innervation. Plasma neurofilament light (NEFL) levels, a clinically relevant biomarker, were also ameliorated in fully treated mice. Intrathecal gene delivery after the onset of peripheral neuropathy offers a significant therapeutic benefit in this disease model, providing a proof of principle for treating patients with CMT1X at different ages.
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Affiliation(s)
- A Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - J Richter
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Tryfonos
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A J Heslegrave
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - I Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A M Rossor
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - H Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
- UK Dementia Research Institute at UCL, London, United Kingdom
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - M M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - C Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - K A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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24
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Yang W, Lampe PD, Kensel-Hammes P, Hesson J, Ware CB, Crisa L, Cirulli V. Connexin 43 Functions as a Positive Regulator of Stem Cell Differentiation into Definitive Endoderm and Pancreatic Progenitors. iScience 2019; 19:450-460. [PMID: 31430690 PMCID: PMC6708988 DOI: 10.1016/j.isci.2019.07.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 05/04/2019] [Accepted: 07/18/2019] [Indexed: 01/05/2023] Open
Abstract
Efficient stem cell differentiation into pancreatic islet cells is of critical importance for the development of cell replacement therapies for diabetes. Here, we identify the expression pattern of connexin 43 (Cx43), a gap junction (GJ) channel protein, in human embryonic stem cell (hESC)-derived definitive endoderm (DE) and primitive gut tube cells, representing early lineages for posterior foregut (PF), pancreatic progenitors (PP), pancreatic endocrine progenitors (PE), and islet cells. As the function of GJ channels is dependent on their gating status, we tested the impact of supplementing hESC-derived PP cell cultures with AAP10, a peptide that promotes Cx43 GJ channel opening. We found that this treatment promotes the expression of DE markers FoxA2 and Sox17, leads to a more efficient derivation of DE, and improves the yield of PF, PP, and PE cells. These results demonstrate a functional involvement of GJ channels in the differentiation of embryonic stem cells into pancreatic cell lineages.
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Affiliation(s)
- Wendy Yang
- Department of Medicine, UW Diabetes Institute, University of Washington, 850 Republican Street, S475, Seattle, WA 98109, USA
| | - Paul D Lampe
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Patricia Kensel-Hammes
- Department of Medicine, UW Diabetes Institute, University of Washington, 850 Republican Street, S475, Seattle, WA 98109, USA
| | - Jennifer Hesson
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, S480, Seattle, WA 98109, USA
| | - Carol B Ware
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, S480, Seattle, WA 98109, USA
| | - Laura Crisa
- Department of Medicine, UW Diabetes Institute, University of Washington, 850 Republican Street, S475, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, S480, Seattle, WA 98109, USA; Department of Pharmacology, University of Washington, Seattle, WA, USA.
| | - Vincenzo Cirulli
- Department of Medicine, UW Diabetes Institute, University of Washington, 850 Republican Street, S475, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, S480, Seattle, WA 98109, USA; Department of Pharmacology, University of Washington, Seattle, WA, USA.
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25
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Murakami T, Sunada Y. Schwann Cell and the Pathogenesis of Charcot–Marie–Tooth Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:301-321. [DOI: 10.1007/978-981-32-9636-7_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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26
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Bortolozzi M. What's the Function of Connexin 32 in the Peripheral Nervous System? Front Mol Neurosci 2018; 11:227. [PMID: 30042657 PMCID: PMC6048289 DOI: 10.3389/fnmol.2018.00227] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/11/2018] [Indexed: 12/26/2022] Open
Abstract
Connexin 32 (Cx32) is a fundamental protein in the peripheral nervous system (PNS) as its mutations cause the X-linked form of Charcot–Marie–Tooth disease (CMT1X), the second most common form of hereditary motor and sensory neuropathy and a demyelinating disease for which there is no effective therapy. Since mutations of the GJB1 gene encoding Cx32 were first reported in 1993, over 450 different mutations associated with CMT1X including missense, frameshift, deletion and non-sense ones have been identified. Despite the availability of a sizable number of studies focusing on normal and mutated Cx32 channel properties, the crucial role played by Cx32 in the PNS has not yet been elucidated, as well as the molecular pathogenesis of CMT1X. Is Cx32 fundamental during a particular phase of Schwann cell (SC) life? Are Cx32 paired (gap junction, GJ) channels in myelinated SCs important for peripheral nerve homeostasis? The attractive hypothesis that short coupling of adjacent myelin layers by Cx32 GJs is required for efficient diffusion of K+ and signaling molecules is still debated, while a growing body of evidence is supporting other possible functions of Cx32 in the PNS, mainly related to Cx32 unpaired channels (hemichannels), which could be involved in a purinergic-dependent pathway controlling myelination. Here we review the intriguing puzzle of findings about Cx32 function and dysfunction, discussing possible directions for future investigation.
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Affiliation(s)
- Mario Bortolozzi
- Department of Physics and Astronomy G. Galilei, University of Padua, Padua, Italy.,Venetian Institute of Molecular Medicine (VIMM), Padua, Italy.,Padova Neuroscience Center (PNC), Padua, Italy
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27
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Kagiava A, Karaiskos C, Richter J, Tryfonos C, Lapathitis G, Sargiannidou I, Christodoulou C, Kleopa KA. Intrathecal gene therapy in mouse models expressing CMT1X mutations. Hum Mol Genet 2018; 27:1460-1473. [PMID: 29462293 DOI: 10.1093/hmg/ddy056] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/10/2018] [Indexed: 11/14/2022] Open
Abstract
Gap junction beta-1 (GJB1) gene mutations affecting the gap junction protein connexin32 (Cx32) cause the X-linked Charcot-Marie-Tooth disease (CMT1X), a common inherited neuropathy. Targeted expression of virally delivered Cx32 in Schwann cells following intrathecal injection of lentiviral vectors in the Cx32 knockout (KO) mouse model of the disease has led to morphological and functional improvement. To examine whether this approach could be effective in CMT1X patients expressing different Cx32 mutants, we treated transgenic Cx32 KO mice expressing the T55I, R75W or N175D CMT1X mutations. All three mutants were localized in the perinuclear compartment of myelinating Schwann cells consistent with retention in the ER (T55I) or Golgi (R75W, N175D) and loss of physiological expression in the non-compact myelin. Following intrathecal delivery of the GJB1 gene we detected the virally delivered wild-type (WT) Cx32 in non-compact myelin of T55I KO mice, but only rarely in N175D KO or R75W KO mice, suggesting dominant-negative effects of the R75W and N175D mutants but not of the T55I mutant on co-expressed WT Cx32. GJB1 treated T55I KO mice showed improved motor performance, lower ratios of abnormally myelinated fibers and reduction of inflammatory cells in spinal roots and peripheral nerves compared with mock-treated littermates. Either partial (N175D KO) or no (R75W KO) improvement was observed in the other two mutant lines. Thus, certain CMT1X mutants may interfere with gene addition therapy for CMT1X. Whereas gene addition can be used for non-interfering CMT1X mutations, further studies will be needed to develop treatments for patients harboring interfering mutations.
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Affiliation(s)
- A Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - C Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - J Richter
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - C Tryfonos
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - G Lapathitis
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - I Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - C Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - K A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
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28
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Lassuthova P, Rebelo AP, Ravenscroft G, Lamont PJ, Davis MR, Manganelli F, Feely SM, Bacon C, Brožková DŠ, Haberlova J, Mazanec R, Tao F, Saghira C, Abreu L, Courel S, Powell E, Buglo E, Bis DM, Baxter MF, Ong RW, Marns L, Lee YC, Bai Y, Isom DG, Barro-Soria R, Chung KW, Scherer SS, Larsson HP, Laing NG, Choi BO, Seeman P, Shy ME, Santoro L, Zuchner S. Mutations in ATP1A1 Cause Dominant Charcot-Marie-Tooth Type 2. Am J Hum Genet 2018. [PMID: 29499166 DOI: 10.1016/j.ajhg.2018.01.023.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022] Open
Abstract
Although mutations in more than 90 genes are known to cause CMT, the underlying genetic cause of CMT remains unknown in more than 50% of affected individuals. The discovery of additional genes that harbor CMT2-causing mutations increasingly depends on sharing sequence data on a global level. In this way-by combining data from seven countries on four continents-we were able to define mutations in ATP1A1, which encodes the alpha1 subunit of the Na+,K+-ATPase, as a cause of autosomal-dominant CMT2. Seven missense changes were identified that segregated within individual pedigrees: c.143T>G (p.Leu48Arg), c.1775T>C (p.Ile592Thr), c.1789G>A (p.Ala597Thr), c.1801_1802delinsTT (p.Asp601Phe), c.1798C>G (p.Pro600Ala), c.1798C>A (p.Pro600Thr), and c.2432A>C (p.Asp811Ala). Immunostaining peripheral nerve axons localized ATP1A1 to the axolemma of myelinated sensory and motor axons and to Schmidt-Lanterman incisures of myelin sheaths. Two-electrode voltage clamp measurements on Xenopus oocytes demonstrated significant reduction in Na+ current activity in some, but not all, ouabain-insensitive ATP1A1 mutants, suggesting a loss-of-function defect of the Na+,K+ pump. Five mutants fall into a remarkably narrow motif within the helical linker region that couples the nucleotide-binding and phosphorylation domains. These findings identify a CMT pathway and a potential target for therapy development in degenerative diseases of peripheral nerve axons.
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Affiliation(s)
- Petra Lassuthova
- DNA Laboratory, Department of Pediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague 150 06, Czech Republic
| | - Adriana P Rebelo
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Gianina Ravenscroft
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | | | - Mark R Davis
- Neurogenetics Unit, Department of Diagnostic Genomics, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomathology, Federico II University, Naples 80131, Italy
| | - Shawna M Feely
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Chelsea Bacon
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Dana Šafka Brožková
- DNA Laboratory, Department of Pediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague 150 06, Czech Republic
| | - Jana Haberlova
- Department of Pediatric Neurology, 2(nd) Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague 150 06, Czech Republic
| | - Radim Mazanec
- Department of Neurology, 2(nd) Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague 150 06, Czech Republic
| | - Feifei Tao
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Cima Saghira
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Lisa Abreu
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Steve Courel
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Eric Powell
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; The Genesis Project foundation, Miami, FL 33136, USA
| | - Elena Buglo
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Dana M Bis
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Megan F Baxter
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Royston W Ong
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Lorna Marns
- Neurogenetics Unit, Department of Diagnostic Genomics, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, Department of Neurology, National Yang-Ming University School of Medicine, 10466 Taipei, Taiwan
| | - Yunhong Bai
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Daniel G Isom
- Department of Pharmacology, Sylvester Comprehensive Cancer Center, and Center for Computational Sciences, University of Miami, Miami, FL 33136, USA
| | - René Barro-Soria
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ki W Chung
- Department of Biological Science, Kongju National University, Gongju 32588, Korea
| | - Steven S Scherer
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - H Peter Larsson
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Nigel G Laing
- Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
| | - Pavel Seeman
- DNA Laboratory, Department of Pediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague 150 06, Czech Republic
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Lucio Santoro
- Department of Neurosciences, Reproductive Sciences and Odontostomathology, Federico II University, Naples 80131, Italy
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Mutations in ATP1A1 Cause Dominant Charcot-Marie-Tooth Type 2. Am J Hum Genet 2018; 102:505-514. [PMID: 29499166 DOI: 10.1016/j.ajhg.2018.01.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/30/2018] [Indexed: 11/22/2022] Open
Abstract
Although mutations in more than 90 genes are known to cause CMT, the underlying genetic cause of CMT remains unknown in more than 50% of affected individuals. The discovery of additional genes that harbor CMT2-causing mutations increasingly depends on sharing sequence data on a global level. In this way-by combining data from seven countries on four continents-we were able to define mutations in ATP1A1, which encodes the alpha1 subunit of the Na+,K+-ATPase, as a cause of autosomal-dominant CMT2. Seven missense changes were identified that segregated within individual pedigrees: c.143T>G (p.Leu48Arg), c.1775T>C (p.Ile592Thr), c.1789G>A (p.Ala597Thr), c.1801_1802delinsTT (p.Asp601Phe), c.1798C>G (p.Pro600Ala), c.1798C>A (p.Pro600Thr), and c.2432A>C (p.Asp811Ala). Immunostaining peripheral nerve axons localized ATP1A1 to the axolemma of myelinated sensory and motor axons and to Schmidt-Lanterman incisures of myelin sheaths. Two-electrode voltage clamp measurements on Xenopus oocytes demonstrated significant reduction in Na+ current activity in some, but not all, ouabain-insensitive ATP1A1 mutants, suggesting a loss-of-function defect of the Na+,K+ pump. Five mutants fall into a remarkably narrow motif within the helical linker region that couples the nucleotide-binding and phosphorylation domains. These findings identify a CMT pathway and a potential target for therapy development in degenerative diseases of peripheral nerve axons.
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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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Kyriakoudi S, Sargiannidou I, Kagiava A, Olympiou M, Kleopa KA. Golgi-retained Cx32 mutants interfere with gene addition therapy for CMT1X. Hum Mol Genet 2017; 26:1622-1633. [PMID: 28334782 DOI: 10.1093/hmg/ddx064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/15/2017] [Indexed: 12/16/2023] Open
Abstract
Numerous GJB1 gene mutations cause the X-linked form of Charcot-Marie-Tooth disease (CMT1X). GJB1 encodes connexin32 (Cx32), which forms trans-myelin gap junctions in Schwann cells. Most GJB1 mutations result in loss-of-function mechanisms, supporting the concept of gene replacement therapy. However, interactions between delivered wild type and endogenously expressed mutant Cx32 may potentially occur in the setting of gene replacement therapy. In order to screen for possible interactions of several representative CMT1X mutants with wild type Cx32 that may interfere with the functional gap junction formation, we established an in vitro screening method co-expressing in HeLa cells wild type Cx32 and one of eight different Cx32 mutants including A39P, A39V, T55I, R75W, M93V, L143P, N175D and R183S. Some of the Golgi-retained mutants hindered gap junction plaque assembly by Cx32 on the cell membrane, while co-immunoprecipitation analysis revealed a partial interaction of wild type protein with Golgi-retained mutants. Dye transfer studies confirmed that Golgi-retained R75W, M93V and N175D but not endoplasmic reticulum-retained T55I had a negative effect on wild type Cx32 function. Finally, in vivo intraneural delivery of the gene encoding the wild type Cx32 in mice bearing either the T55I or R75W mutation on Cx32 knockout background showed that virally delivered protein was correctly localized in mice expressing the endoplasmic reticulum-retained T55I whereas it did not traffic normally in mice expressing the Golgi-retained R75W. Thus, certain Golgi-retained Cx32 mutants may interfere with exogenously delivered Cx32. Screening for mutant-wild type Cx32 interactions should be considered prior to planning gene addition therapy for CMT1X.
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Affiliation(s)
| | | | | | | | - Kleopas A Kleopa
- Neuroscience Laboratory
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
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Hunter G, Powis RA, Jones RA, Groen EJN, Shorrock HK, Lane FM, Zheng Y, Sherman DL, Brophy PJ, Gillingwater TH. Restoration of SMN in Schwann cells reverses myelination defects and improves neuromuscular function in spinal muscular atrophy. Hum Mol Genet 2016; 25:2853-2861. [PMID: 27170316 PMCID: PMC5181642 DOI: 10.1093/hmg/ddw141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/19/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by low levels of SMN protein, primarily affecting lower motor neurons. Recent evidence from SMA and related conditions suggests that glial cells can influence disease severity. Here, we investigated the role of glial cells in the peripheral nervous system by creating SMA mice selectively overexpressing SMN in myelinating Schwann cells (Smn−/−;SMN2tg/0;SMN1SC). Restoration of SMN protein levels restricted solely to Schwann cells reversed myelination defects, significantly improved neuromuscular function and ameliorated neuromuscular junction pathology in SMA mice. However, restoration of SMN in Schwann cells had no impact on motor neuron soma loss from the spinal cord or ongoing systemic and peripheral pathology. This study provides evidence for a defined, intrinsic contribution of glial cells to SMA disease pathogenesis and suggests that therapies designed to include Schwann cells in their target tissues are likely to be required in order to rescue myelination defects and associated disease symptoms.
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Affiliation(s)
- Gillian Hunter
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK,
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Rachael A Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Ross A Jones
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Ewout J N Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Fiona M Lane
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Yinan Zheng
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Diane L Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
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Intrathecal gene therapy rescues a model of demyelinating peripheral neuropathy. Proc Natl Acad Sci U S A 2016; 113:E2421-9. [PMID: 27035961 DOI: 10.1073/pnas.1522202113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Inherited demyelinating peripheral neuropathies are progressive incurable diseases without effective treatment. To develop a gene therapy approach targeting myelinating Schwann cells that can be translatable, we delivered a lentiviral vector using a single lumbar intrathecal injection and a myelin-specific promoter. The human gene of interest, GJB1, which is mutated in X-linked Charcot-Marie-Tooth Disease (CMT1X), was delivered intrathecally into adult Gjb1-null mice, a genetically authentic model of CMT1X that develops a demyelinating peripheral neuropathy. We obtained widespread, stable, and cell-specific expression of connexin32 in up to 50% of Schwann cells in multiple lumbar spinal roots and peripheral nerves. Behavioral and electrophysiological analysis revealed significantly improved motor performance, quadriceps muscle contractility, and sciatic nerve conduction velocities. Furthermore, treated mice exhibited reduced numbers of demyelinated and remyelinated fibers and fewer inflammatory cells in lumbar motor roots, as well as in the femoral motor and sciatic nerves. This study demonstrates that a single intrathecal lentiviral gene delivery can lead to Schwann cell-specific expression in spinal roots extending to multiple peripheral nerves. This clinically relevant approach improves the phenotype of an inherited neuropathy mouse model and provides proof of principle for treating inherited demyelinating neuropathies.
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Kagiava A, Sargiannidou I, Bashiardes S, Richter J, Schiza N, Christodoulou C, Gritti A, Kleopa KA. Gene delivery targeted to oligodendrocytes using a lentiviral vector. J Gene Med 2015; 16:364-73. [PMID: 25394283 DOI: 10.1002/jgm.2813] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/22/2014] [Accepted: 11/07/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Most leukodystrophies result from mutations in genes expressed in oligodendrocytes that may cause autonomous loss of function of cell structural proteins. Therefore, effective gene delivery to oligodendrocytes is necessary to develop future treatments. MATERIALS To achieve this, we cloned a lentiviral vector in which the enhanced green fluorescent protein (EGFP) expression was driven by the oligodendrocyte specific 2,3-cyclic nucleotide 3-phosphodiesterase promoter. The vector was inserted into C57BL/6 neonatal mouse brain by combined intraventricular and parenchymal injections. RESULTS Assessment of EGFP expression revealed a widespread distribution, specifically in cells of the oligodendrocyte linage, starting from postnatal day 6 (P6) in the subventricular zone and spreading through migrating oligodendrocyte precursors. By P30, it was detectable throughout the brain and persisted for at least 3 months, showing an increase both in the number of expressing cells and in intensity over time. EGFP expression was restricted to oligodendrocyte linage cells. On average, 20.3 ± 2.56% of all oligodendrocytes in different central nervous system areas were EGFP-positive, with regional variations. CONCLUSIONS Lentiviral gene delivery using an oligodendrocyte-specific promoter may achieve widespread and long-lasting expression selectively in oligodendrocytes, offering a possibility for gene therapy in certain leukodystrophies, although the relatively low rates of oligodendrocyte transduction are a limitation that remains to be overcome.
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Affiliation(s)
- Alexia Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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35
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Sargiannidou I, Kagiava A, Bashiardes S, Richter J, Christodoulou C, Scherer SS, Kleopa KA. Intraneural GJB1 gene delivery improves nerve pathology in a model of X-linked Charcot-Marie-Tooth disease. Ann Neurol 2015; 78:303-16. [PMID: 26010264 DOI: 10.1002/ana.24441] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 11/11/2022]
Abstract
OBJECTIVE X-linked Charcot-Marie-Tooth disease (CMT1X) is a common inherited neuropathy caused by mutations in the GJB1 gene encoding the gap junction protein connexin32 (Cx32). Clinical studies and disease models indicate that neuropathy mainly results from Schwann cell autonomous, loss-of-function mechanisms; therefore, CMT1X may be treatable by gene replacement. METHODS A lentiviral vector LV.Mpz-GJB1 carrying the GJB1 gene under the Schwann cell-specific myelin protein zero (Mpz) promoter was generated and delivered into the mouse sciatic nerve by a single injection immediately distal to the sciatic notch. Enhanced green fluorescent protein (EGFP) reporter gene expression was quantified and Cx32 expression was examined on a Cx32 knockout (KO) background. A gene therapy trial was performed in a Cx32 KO model of CMT1X. RESULTS EGFP was expressed throughout the length of the sciatic nerve in up to 50% of Schwann cells starting 2 weeks after injection and remaining stable for up to 16 weeks. Following LV.Mpz-GJB1 injection into Cx32 KO nerves, we detected Cx32 expression and correct localization in non-compact myelin areas where gap junctions are normally formed. Gene therapy trial by intraneural injection in groups of 2-month-old Cx32 KO mice, before demyelination onset, significantly reduced the ratio of abnormally myelinated fibers (p = 0.00148) and secondary inflammation (p = 0.0178) at 6 months of age compared to mock-treated animals. INTERPRETATION Gene delivery using a lentiviral vector leads to efficient gene expression specifically in Schwann cells. Restoration of Cx32 expression ameliorates nerve pathology in a disease model and provides a promising approach for future treatments of CMT1X and other inherited neuropathies.
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Affiliation(s)
| | | | - Stavros Bashiardes
- Department of Molecular Virology, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Jan Richter
- Department of Molecular Virology, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Christina Christodoulou
- Department of Molecular Virology, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Steven S Scherer
- Department of Neurology, University of Pennsylvania, Philadelphia, PA
| | - Kleopas A Kleopa
- Neuroscience Laboratory
- Neurology Clinics, Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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36
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Connexins, gap junctions and peripheral neuropathy. Neurosci Lett 2015; 596:27-32. [DOI: 10.1016/j.neulet.2014.10.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 11/23/2022]
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Schiza N, Sargiannidou I, Kagiava A, Karaiskos C, Nearchou M, Kleopa KA. Transgenic replacement of Cx32 in gap junction-deficient oligodendrocytes rescues the phenotype of a hypomyelinating leukodystrophy model. Hum Mol Genet 2015; 24:2049-64. [PMID: 25524707 DOI: 10.1093/hmg/ddu725] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oligodendrocytes are coupled by gap junctions (GJs) formed mainly by connexin47 (Cx47) and Cx32. Recessive GJC2/Cx47 mutations cause Pelizaeus-Merzbacher-like disease, a hypomyelinating leukodystrophy, while GJB1/Cx32 mutations cause neuropathy and chronic or acute-transient encephalopathy syndromes. Cx32/Cx47 double knockout (Cx32/Cx47dKO) mice develop severe CNS demyelination beginning at 1 month of age leading to death within weeks, offering a relevant model to study disease mechanisms. In order to clarify whether the loss of oligodendrocyte connexins has cell autonomous effects, we generated transgenic mice expressing the wild-type human Cx32 under the control of the mouse proteolipid protein promoter, obtaining exogenous hCx32 expression in oligodendrocytes. By crossing these mice with Cx32KO mice, we obtained expression of hCx32 on Cx32KO background. Immunohistochemical and immunoblot analysis confirmed strong CNS expression of hCx32 specifically in oligodendrocytes and correct localization forming GJs at cell bodies and along the myelin sheath. TG(+)Cx32/Cx47dKO mice generated by further crossing with Cx47KO mice showed that transgenic expression of hCx32 rescued the severe early phenotype of CNS demyelination in Cx32/Cx47dKO mice, resulting in marked improvement of behavioral abnormalities at 1 month of age, and preventing the early mortality. Furthermore, TG(+)Cx32/Cx47dKO mice showed significant improvement of myelination compared with Cx32/Cx47dKO CNS at 1 month of age, while the inflammatory and astrogliotic changes were fully reversed. Our study confirms that loss of oligodendrocyte GJs has cell autonomous effects and that re-establishment of GJ connectivity by replacement of least one GJ protein provides correction of the leukodystrophy phenotype.
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Affiliation(s)
| | | | | | | | - Marianna Nearchou
- Department of Molecular Pathology and Electron Microscopy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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Bouhy D, Timmerman V. Animal models and therapeutic prospects for Charcot-Marie-Tooth disease. Ann Neurol 2013; 74:391-6. [PMID: 23913540 DOI: 10.1002/ana.23987] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/04/2013] [Accepted: 07/29/2013] [Indexed: 12/14/2022]
Abstract
Charcot-Marie-Tooth (CMT) neuropathies are inherited neuromuscular disorders caused by a length-dependent neurodegeneration of peripheral nerves. More than 900 mutations in 60 different genes are causative of the neuropathy. Despite significant progress in therapeutic strategies, the disease remains incurable. The increasing number of genes linked to the disease, and their considerable clinical and genetic heterogeneity render the development of these strategies particularly challenging. In this context, cellular and animals models provide powerful tools. Efficient motor and sensory tests have been developed to assess the behavioral phenotype in transgenic animal models (rodent and fly). When these models reproduce a phenotype comparable to CMT, they allow therapeutic approaches and the discovery of modifiers and biomarkers. In this review, we describe the most convincing transgenic rodent and fly models of CMT and how they can lead to clinical trial. We also discuss the challenges that the research, the clinic, and the pharmaceutical industry will face in developing efficient and accessible treatment for CMT patients.
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Affiliation(s)
- Delphine Bouhy
- Peripheral Neuropathy Group, Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
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SMN-dependent intrinsic defects in Schwann cells in mouse models of spinal muscular atrophy. Hum Mol Genet 2013; 23:2235-50. [DOI: 10.1093/hmg/ddt612] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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40
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Bouhy D, Timmerman V. Modèles animaux dans la maladie de Charcot-Marie-Tooth et applications de la compréhension de la maladie chez l’homme. Rev Neurol (Paris) 2013; 169:971-7. [DOI: 10.1016/j.neurol.2013.07.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 07/25/2013] [Accepted: 07/26/2013] [Indexed: 11/26/2022]
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Söhl G, Hombach S, Degen J, Odermatt B. The oligodendroglial precursor cell line Oli-neu represents a cell culture system to examine functional expression of the mouse gap junction gene connexin29 (Cx29). Front Pharmacol 2013; 4:83. [PMID: 23825458 PMCID: PMC3695394 DOI: 10.3389/fphar.2013.00083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 06/10/2013] [Indexed: 11/13/2022] Open
Abstract
The potential gap junction forming mouse connexin29 (Cx29) protein is concomitantly expressed with connexin32 (Cx32) in peripheral myelin forming Schwann cells and together with both Cx32 and connexin47 (Cx47) in oligodendrocytes of the CNS. To study the genomic structure and functional expression of Cx29, either primary cells or cell culture systems might be selected, from which the latter are easier to cultivate. Both structure and expression of Cx29 is still not fully understood. In the mouse sciatic nerve, brain and the oligodendroglial precursor cell line Oli-neu the Cx29 gene is processed in two transcript isoforms both harboring a unique reading frame. In contrast to Cx32 and Cx47, only Cx29 protein is abundantly expressed in undifferentiated as well as differentiated Oli-neu cells but the absence of Etbr dye transfer after microinjection concealed the function of Cx29-mediated gap junction communication between those cells. Although HeLa cells stably transfected with Cx29 or Cx29-eGFP neither demonstrated any permeability for Lucifer yellow nor for neurobiotin, blocking of Etbr uptake from the media by gap junction blockers does suppose a role of Cx29 in hemi-channel function. Thus, we conclude that, due to its high abundance of Cx29 expression and its reproducible culture conditions, the oligodendroglial precursor cell line Oli-neu might constitute an appropriate cell culture system to study molecular mechanisms or putative extracellular stimuli to functionally open Cx29 channels or hemi-channels.
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Affiliation(s)
- Goran Söhl
- Abteilung Molekulargenetik, Institut für Genetik, Universität Bonn Bonn, Germany
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42
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Kleopa KA, Abrams CK, Scherer SS. How do mutations in GJB1 cause X-linked Charcot-Marie-Tooth disease? Brain Res 2012; 1487:198-205. [PMID: 22771394 PMCID: PMC3488165 DOI: 10.1016/j.brainres.2012.03.068] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 03/24/2012] [Indexed: 11/26/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMT1X) is the second most common form of hereditary motor and sensory neuropathy. The clinical phenotype is characterized by progressive weakness, atrophy, and sensory abnormalities that are most pronounced in the distal extremities. Some patients have CNS manifestations. Affected males have moderate to severe symptoms, whereas heterozygous females are usually less affected. Neurophysiology shows intermediate slowing of conduction and length-dependent axonal loss. Nerve biopsies show more prominent axonal degeneration than de/remyelination. Mutations in GJB1, the gene that encodes the gap junction (GJ) protein connexin32 (Cx32) cause CMT1X; more than 400 different mutations have been described. Many Cx32 mutants fail to form functional GJs, or form GJs with abnormal biophysical properties. Schwann cells and oligodendrocytes express Cx32, and the GJs formed by Cx32 play an important role in the homeostasis of myelinated axons. Animal models of CMT1X demonstrate that loss of Cx32 in myelinating Schwann cells causes a demyelinating neuropathy. Effective therapies remain to be developed. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Kleopas A Kleopa
- Neurology Clinics and Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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Abstract
The X-linked form of Charcot-Marie-Tooth disease (CMT1X) is the second most common form of hereditary motor and sensory neuropathy. The clinical phenotype is characterized by progressive muscle atrophy and weakness, areflexia, and variable sensory abnormalities; central nervous system manifestations occur, too. Affected males have moderate to severe symptoms, whereas heterozygous females are usually less affected. Neurophysiology shows intermediate slowing of conduction and distal axonal loss. Nerve biopsies show more prominent axonal degeneration than de/remyelination. More than 400 different mutations in GJB1, the gene that encodes the gap junction (GJ) protein connexin32 (Cx32), cause CMT1X. Many Cx32 mutants fail to form functional GJs, or form GJs with abnormal biophysical properties. Schwann cells and oligodendrocytes express Cx32, and the GJs formed by Cx32 play an important role in the homeostasis of myelinated axons. Animal models of CMT1X demonstrate that loss of Cx32 in myelinating Schwann cells causes a demyelinating neuropathy. An effective therapy remains to be developed.
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Affiliation(s)
- Steven S Scherer
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Drp2 and periaxin form Cajal bands with dystroglycan but have distinct roles in Schwann cell growth. J Neurosci 2012; 32:9419-28. [PMID: 22764250 DOI: 10.1523/jneurosci.1220-12.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cajal bands are cytoplasmic channels flanked by appositions where the abaxonal surface of Schwann cell myelin apposes and adheres to the overlying plasma membrane. These appositions contain a dystroglycan complex that includes periaxin and dystrophin-related protein 2 (Drp2). Loss of periaxin disrupts appositions and Cajal bands in Schwann cells and causes a severe demyelinating neuropathy in mouse and human. Here, we investigated the role of mouse Drp2 in apposition assembly and Cajal band function and compared it with periaxin. We show that periaxin and Drp2 are not only both required to form appositions, but they must also interact. Periaxin-Drp2 interaction is also required for Drp2 phosphorylation, but phosphorylation is not required for the assembly of appositions. Drp2 loss causes corresponding increases in Dystrophin family members, utrophin and dystrophin Dp116, although dystroglycan remains unchanged. We also show that all dystroglycan complexes in Schwann cells use the uncleaved form of β-dystroglycan. Drp2-null Schwann cells have disrupted appositions and Cajal bands, and they undergo focal hypermyelination and concomitant demyelination. Nevertheless, they do not have the short internodal lengths and associated reduced nerve conduction velocity seen in the absence of periaxin, showing that periaxin regulates Schwann cell elongation independent of its role in the dystroglycan complex. We conclude that the primary role of the dystroglycan complex in appositions is to stabilize and limit the radial growth of myelin.
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Stauch K, Kieken F, Sorgen P. Characterization of the structure and intermolecular interactions between the connexin 32 carboxyl-terminal domain and the protein partners synapse-associated protein 97 and calmodulin. J Biol Chem 2012; 287:27771-88. [PMID: 22718765 PMCID: PMC3431650 DOI: 10.1074/jbc.m112.382572] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/20/2012] [Indexed: 12/20/2022] Open
Abstract
In Schwann cells, connexin 32 (Cx32) can oligomerize to form intracellular gap junction channels facilitating a shorter pathway for metabolite diffusion across the layers of the myelin sheath. The mechanisms of Cx32 intracellular channel regulation have not been clearly defined. However, Ca(2+), pH, and the phosphorylation state can regulate Cx32 gap junction channels, in addition to the direct interaction of protein partners with the carboxyl-terminal (CT) domain. In this study, we used different biophysical methods to determine the structure and characterize the interaction of the Cx32CT domain with the protein partners synapse-associated protein 97 (SAP97) and calmodulin (CaM). Our results revealed that the Cx32CT is an intrinsically disordered protein that becomes α-helical upon binding CaM. We identified the GUK domain as the minimal SAP97 region necessary for the Cx32CT interaction. The Cx32CT residues affected by the binding of CaM and the SAP97 GUK domain were determined as well as the dissociation constants for these interactions. We characterized three Cx32CT Charcot-Marie-Tooth disease mutants (R219H, R230C, and F235C) and identified that whereas they all formed functional channels, they all showed reduced binding affinity for SAP97 and CaM. Additionally, we report that in RT4-D6P2T rat schwannoma cells, Cx32 is differentially phosphorylated and exists in a complex with SAP97 and CaM. Our studies support the importance of protein-protein interactions in the regulation of Cx32 gap junction channels and myelin homeostasis.
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Affiliation(s)
- Kelly Stauch
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Fabien Kieken
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Paul Sorgen
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
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Fledrich R, Stassart RM, Sereda MW. Murine therapeutic models for Charcot-Marie-Tooth (CMT) disease. Br Med Bull 2012; 102:89-113. [PMID: 22551516 DOI: 10.1093/bmb/lds010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION OR BACKGROUND Charcot-Marie-Tooth (CMT) disease represents a broad group of inherited motor and sensory neuropathies which can originate from various genetic aberrations, e.g. mutations, deletions and duplications. SOURCES OF DATA We performed a literature review on murine animal models of CMT disease with regard to experimental therapeutic approaches. Hereby, we focussed on the demyelinating subforms of CMT (CMT1). PubMed items were CMT, animal model, demyelination and therapy. AREAS OF AGREEMENT Patients affected by CMT suffer from slowly progressive, distally pronounced muscle atrophy caused by an axonal loss. The disease severity is highly variable and impairments may result in wheelchair boundness. No therapy is available yet. AREAS OF CONTROVERSY Numerous rodent models for the various CMT subtypes are available today. The selection of the correct animal model for the specific CMT subtype provides an important prerequisite for the successful translation of experimental findings in patients. GROWING POINTS Despite more than 20 years of remarkable progress in CMT research, the disease is still left untreatable. There is a growing number of experimental therapeutic strategies that may be translated into future clinical trials in patients with CMT. AREAS TIMELY FOR DEVELOPING RESEARCH The slow disease progression and insensitive outcome measures hamper clinical therapy trials in CMT. Biomarkers may provide powerful tools to monitor therapeutic efficacy. Recently, we have shown that transcriptional profiling can be utilized to assess and predict the disease severity in a transgenic rat model and in affected humans.
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Affiliation(s)
- Robert Fledrich
- Research Group 'Molecular and Translational Neurology', Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
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Napoli I, Noon LA, Ribeiro S, Kerai AP, Parrinello S, Rosenberg LH, Collins MJ, Harrisingh MC, White IJ, Woodhoo A, Lloyd AC. A central role for the ERK-signaling pathway in controlling Schwann cell plasticity and peripheral nerve regeneration in vivo. Neuron 2012; 73:729-42. [PMID: 22365547 DOI: 10.1016/j.neuron.2011.11.031] [Citation(s) in RCA: 294] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2011] [Indexed: 12/27/2022]
Abstract
Following damage to peripheral nerves, a remarkable process of clearance and regeneration takes place. Axons downstream of the injury degenerate, while the nerve is remodeled to direct axonal regrowth. Schwann cells are important for this regenerative process. "Sensing" damaged axons, they dedifferentiate to a progenitor-like state, in which they aid nerve regeneration. Here, we demonstrate that activation of an inducible Raf-kinase transgene in myelinated Schwann cells is sufficient to control this plasticity by inducing severe demyelination in the absence of axonal damage, with the period of demyelination/ataxia determined by the duration of Raf activation. Remarkably, activation of Raf-kinase also induces much of the inflammatory response important for nerve repair, including breakdown of the blood-nerve barrier and the influx of inflammatory cells. This reversible in vivo model identifies a central role for ERK signaling in Schwann cells in orchestrating nerve repair and is a powerful system for studying peripheral neuropathies and cancer.
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Affiliation(s)
- Ilaria Napoli
- MRC Laboratory for Molecular Cell Biology and the UCL Cancer Institute, University College London, Gower Street, London WC1E 6BT, UK
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Mones S, Bordignon B, Fontes M. Connexin 32 is involved in mitosis. Glia 2012; 60:457-64. [PMID: 22131286 DOI: 10.1002/glia.22279] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 11/11/2011] [Indexed: 12/12/2022]
Abstract
The X-linked form of Charcot-Marie-Tooth disorder (CMTX) is the second most frequent type (15% of CMT forms). It involves the GJB1 gene coding for connexin 32, a protein involved in gap junction formation and function. There is no curative treatment for CMTX. We present data on transgenic lines that was accomplished by inserting a human BAC carrying the GJB1 gene, in which two different mutations in connexin 32 (Cx32) observed in patients were introduced. Investigation of these models implicated Cx32 in the control of mitotic stability. The model in which Gjb1 has been invalidated had the same phenotype. This new function for Cx32 was recently confirmed by results from the Mitocheck program. Locomotor impediment was seen in the behavior of these animals, the severity of which correlated with transgene copy number and RNA expression.
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Affiliation(s)
- Saleh Mones
- EA 4263, Therapy of Genetic Disorders, Faculté de Médecine de la Timone, Université d'AIX-Marseille, Marseille, France
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Nualart-Marti A, Solsona C, Fields RD. Gap junction communication in myelinating glia. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:69-78. [PMID: 22326946 DOI: 10.1016/j.bbamem.2012.01.024] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 01/17/2012] [Accepted: 01/26/2012] [Indexed: 10/14/2022]
Abstract
Gap junction communication is crucial for myelination and axonal survival in both the peripheral nervous system (PNS) and central nervous system (CNS). This review examines the different types of gap junctions in myelinating glia of the PNS and CNS (Schwann cells and oligodendrocytes respectively), including their functions and involvement in neurological disorders. Gap junctions mediate intercellular communication among Schwann cells in the PNS, and among oligodendrocytes and between oligodendrocytes and astrocytes in the CNS. Reflexive gap junctions mediating transfer between different regions of the same cell promote communication between cellular compartments of myelinating glia that are separated by layers of compact myelin. Gap junctions in myelinating glia regulate physiological processes such as cell growth, proliferation, calcium signaling, and participate in extracellular signaling via release of neurotransmitters from hemijunctions. In the CNS, gap junctions form a glial network between oligodendrocytes and astrocytes. This transcellular communication is hypothesized to maintain homeostasis by facilitating restoration of membrane potential after axonal activity via electrical coupling and the re-distribution of potassium ions released from axons. The generation of transgenic mice for different subsets of connexins has revealed the contribution of different connexins in gap junction formation and illuminated new subcellular mechanisms underlying demyelination and cognitive defects. Alterations in metabolic coupling have been reported in animal models of X-linked Charcot-Marie-Tooth disease (CMTX) and Pelizaeus-Merzbarcher-like disease (PMLD), which are caused by mutations in the genes encoding for connexin 32 and connexin 47 respectively. Future research identifying the expression and regulation of gap junctions in myelinating glia is likely to provide a better understanding of myelinating glia in nervous system function, plasticity, and disease. This article is part of a Special Issue entitled: The Communicating junctions, roles and dysfunctions.
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Affiliation(s)
- Anna Nualart-Marti
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain.
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