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Saffari A, Lau T, Tajsharghi H, Karimiani EG, Kariminejad A, Efthymiou S, Zifarelli G, Sultan T, Toosi MB, Sedighzadeh S, Siu VM, Ortigoza-Escobar JD, AlShamsi AM, Ibrahim S, Al-Sannaa NA, Al-Hertani W, Sandra W, Tarnopolsky M, Alavi S, Li C, Day-Salvatore DL, Martínez-González MJ, Levandoski KM, Bedoukian E, Madan-Khetarpal S, Idleburg MJ, Menezes MJ, Siddharth A, Platzer K, Oppermann H, Smitka M, Collins F, Lek M, Shahrooei M, Ghavideldarestani M, Herman I, Rendu J, Faure J, Baker J, Bhambhani V, Calderwood L, Akhondian J, Imannezhad S, Mirzadeh HS, Hashemi N, Doosti M, Safi M, Ahangari N, Torbati PN, Abedini S, Salpietro V, Gulec EY, Eshaghian S, Ghazavi M, Pascher MT, Vogel M, Abicht A, Moutton S, Bruel AL, Rieubland C, Gallati S, Strom TM, Lochmüller H, Mohammadi MH, Alvi JR, Zackai EH, Keena BA, Skraban CM, Berger SI, Andrew EH, Rahimian E, Morrow MM, Wentzensen IM, Millan F, Henderson LB, Dafsari HS, Jungbluth H, Gomez-Ospina N, McRae A, Peter M, Veltra D, Marinakis NM, Sofocleous C, Ashrafzadeh F, Pehlivan D, Lemke JR, Melki J, Benezit A, Bauer P, Weis D, Lupski JR, Senderek J, Christodoulou J, Chung WK, Goodchild R, Offiah AC, Moreno-De-Luca A, Suri M, Ebrahimi-Fakhari D, Houlden H, Maroofian R. The clinical and genetic spectrum of autosomal-recessive TOR1A-related disorders. Brain 2023; 146:3273-3288. [PMID: 36757831 PMCID: PMC10393417 DOI: 10.1093/brain/awad039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/20/2022] [Accepted: 01/23/2023] [Indexed: 02/10/2023] Open
Abstract
In the field of rare diseases, progress in molecular diagnostics led to the recognition that variants linked to autosomal-dominant neurodegenerative diseases of later onset can, in the context of biallelic inheritance, cause devastating neurodevelopmental disorders and infantile or childhood-onset neurodegeneration. TOR1A-associated arthrogryposis multiplex congenita 5 (AMC5) is a rare neurodevelopmental disorder arising from biallelic variants in TOR1A, a gene that in the heterozygous state is associated with torsion dystonia-1 (DYT1 or DYT-TOR1A), an early-onset dystonia with reduced penetrance. While 15 individuals with AMC5-TOR1A have been reported (less than 10 in detail), a systematic investigation of the full disease-associated spectrum has not been conducted. Here, we assess the clinical, radiological and molecular characteristics of 57 individuals from 40 families with biallelic variants in TOR1A. Median age at last follow-up was 3 years (0-24 years). Most individuals presented with severe congenital flexion contractures (95%) and variable developmental delay (79%). Motor symptoms were reported in 79% and included lower limb spasticity and pyramidal signs, as well as gait disturbances. Facial dysmorphism was an integral part of the phenotype, with key features being a broad/full nasal tip, narrowing of the forehead and full cheeks. Analysis of disease-associated manifestations delineated a phenotypic spectrum ranging from normal cognition and mild gait disturbance to congenital arthrogryposis, global developmental delay, intellectual disability, absent speech and inability to walk. In a subset, the presentation was consistent with foetal akinesia deformation sequence with severe intrauterine abnormalities. Survival was 71%, with higher mortality in males. Death occurred at a median age of 1.2 months (1 week-9 years), due to respiratory failure, cardiac arrest or sepsis. Analysis of brain MRI studies identified non-specific neuroimaging features, including a hypoplastic corpus callosum (72%), foci of signal abnormality in the subcortical and periventricular white matter (55%), diffuse white matter volume loss (45%), mega cisterna magna (36%) and arachnoid cysts (27%). The molecular spectrum included 22 distinct variants, defining a mutational hotspot in the C-terminal domain of the Torsin-1A protein. Genotype-phenotype analysis revealed an association of missense variants in the 3-helix bundle domain to an attenuated phenotype, while missense variants near the Walker A/B motif as well as biallelic truncating variants were linked to early death. In summary, this systematic cross-sectional analysis of a large cohort of individuals with biallelic TOR1A variants across a wide age-range delineates the clinical and genetic spectrum of TOR1A-related autosomal-recessive disease and highlights potential predictors for disease severity and survival.
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Affiliation(s)
- Afshin Saffari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Division of Child Neurology and Inherited Metabolic Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Tracy Lau
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | - Homa Tajsharghi
- School of Health Sciences, Division of Biomedicine, University of Skovde, Skovde, Sweden
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace, London, UK
- Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad, Iran
| | | | - Stephanie Efthymiou
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | | | - Tipu Sultan
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | - Mehran Beiraghi Toosi
- Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Sahar Sedighzadeh
- Department of Biological Sciences, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
- KaryoGen, Isfahan, Iran
| | - Victoria Mok Siu
- Division of Medical Genetics, Department of Pediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Juan Darío Ortigoza-Escobar
- Movement Disorders Unit, Pediatric Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain
| | - Aisha M AlShamsi
- Genetic Division, Pediatrics Department, Tawam Hospital, Al Ain, UAE
| | - Shahnaz Ibrahim
- Department of pediatrics and child Health, Aga Khan University, Karachi, Pakistan
| | | | - Walla Al-Hertani
- Harvard Medical School, Boston Children's Hospital, Department of Pediatrics, Division of Genetics and Genomics, Boston, MA, USA
| | - Whalen Sandra
- APHP UF de Génétique Clinique, Centre de Référence des Anomalies du Développement et Syndromes Malformatifs, APHP, Hôpital Armand Trousseau, ERN ITHACA, Sorbonne Université, Paris, France
| | - Mark Tarnopolsky
- Department of Pediatrics (MT – Neuromuscular and Neurometabolics, CL – Medical Genetics), McMaster Children's Hospital, Hamilton, Ontario, Canada
| | - Shahryar Alavi
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | - Chumei Li
- Department of Pediatrics (MT – Neuromuscular and Neurometabolics, CL – Medical Genetics), McMaster Children's Hospital, Hamilton, Ontario, Canada
| | - Debra-Lynn Day-Salvatore
- The Department of Medical Genetics and Genomic Medicine at Saint Peter's University Hospital, New Brunswick, NJ, USA
| | | | - Kristin M Levandoski
- The Department of Medical Genetics and Genomic Medicine at Saint Peter's University Hospital, New Brunswick, NJ, USA
| | - Emma Bedoukian
- Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Suneeta Madan-Khetarpal
- Division of Genetic and Genomic Medicine, Department of Pediatrics, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michaela J Idleburg
- Division of Genetic and Genomic Medicine, Department of Pediatrics, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Minal Juliet Menezes
- Department of Anaesthesia, the Children's Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Child and Adolescent Health, and Specialty of Genomic Medicine, Sydney Medical School, Sydney University, Sydney, NSW, Australia
| | - Aishwarya Siddharth
- Harvard Medical School, Boston Children's Hospital, Department of Pediatrics, Division of Genetics and Genomics, Boston, MA, USA
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Henry Oppermann
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Martin Smitka
- Department of Neuropediatrics, Medical Faculty Carl Gustav Carus, Technical University Dresden, Dresden, Germany
| | - Felicity Collins
- Discipline of Child and Adolescent Health, and Specialty of Genomic Medicine, Sydney Medical School, Sydney University, Sydney, NSW, Australia
- Department of Clinical Genetics, Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Monkol Lek
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mohmmad Shahrooei
- Medical Laboratory of Dr. Shahrooei, Tehran, Iran
- Department of Microbiology and Immunology, Clinical and Diagnostic Immunology, KU Leuven, Leuven, Belgium
| | | | - Isabella Herman
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children's Hospital, Houston, TX, USA
- Division of Pediatric Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA
| | - John Rendu
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Julien Faure
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Janice Baker
- Division of Genetics and Genomic Medicine, Children's Hospital and Clinics of Minnesota, Minneapolis, Minnesota, USA
| | - Vikas Bhambhani
- Division of Genetics and Genomic Medicine, Children's Hospital and Clinics of Minnesota, Minneapolis, Minnesota, USA
| | - Laurel Calderwood
- Lucile Packard Children's Hospital Stanford, Palo Alto, CA, USA
- Department of Pediatrics, Division of Medical Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Javad Akhondian
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Shima Imannezhad
- Department of Pediatric Neurology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hanieh Sadat Mirzadeh
- Department of Pediatric Neurology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Narges Hashemi
- Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Doosti
- Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad, Iran
| | - Mojtaba Safi
- Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad, Iran
| | - Najmeh Ahangari
- Innovative medical research centre, Mashhad branch, Islamic Azad University, Mashhad, Iran
| | | | - Soheila Abedini
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | - Vincenzo Salpietro
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | - Elif Yilmaz Gulec
- Istanbul Medeniyet University Medical School, Department of Medical Genetics, Istanbul, Turkey
| | | | - Mohammadreza Ghazavi
- Department of Pediatric Neurology, Imam Hossein Children's Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Michael T Pascher
- Friedrich-Baur-Institute at the Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - Marina Vogel
- Friedrich-Baur-Institute at the Department of Neurology, University Hospital, LMU Munich, Munich, Germany
- Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | - Angela Abicht
- Friedrich-Baur-Institute at the Department of Neurology, University Hospital, LMU Munich, Munich, Germany
- Medizinisch Genetisches Zentrum, Munich, German
| | - Sébastien Moutton
- Multidisciplinary Center for Prenatal Diagnosis, Pôle Mère Enfant, Maison de Santé Protestante Bordeaux Bagatelle, Talence, France
| | - Ange-Line Bruel
- Équipe Génétique des Anomalies du Développement (GAD), INSERM UMR1231, Dijon, France
- Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, Dijon University Hospital, Dijon, France
| | - Claudine Rieubland
- Division of Human Genetics, Department of Pediatrics, Inselspital, University of Bern, Switzerland
| | - Sabina Gallati
- Division of Human Genetics, Department of Pediatrics, Inselspital, University of Bern, Switzerland
| | - Tim M Strom
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada
| | | | - Javeria Raza Alvi
- Department of Pediatric Neurology, The Children's Hospital and the University of Child Health Sciences, Lahore, Pakistan
| | - Elaine H Zackai
- Division of Human Genetics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Beth A Keena
- Division of Human Genetics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Cara M Skraban
- Division of Human Genetics, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Seth I Berger
- Children's National Research Institute, Washington DC, USA
| | - Erin H Andrew
- Children's National Research Institute, Washington DC, USA
| | | | | | | | | | | | - Hormos Salimi Dafsari
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Max-Planck-Institute for Biology of Ageing and CECAD, Cologne, Germany
- Department of Paediatric Neurology - Neuromuscular Service, Evelina London Children's Hospital, Guy's & St Thomas' Hospital NHS Foundation Trust, London, UK
| | - Heinz Jungbluth
- Department of Paediatric Neurology - Neuromuscular Service, Evelina London Children's Hospital, Guy's & St Thomas' Hospital NHS Foundation Trust, London, UK
- Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
| | | | - Anne McRae
- Division of Genetics, Genomics, and Metabolism, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, USA
| | - Merlene Peter
- Division of Genetics, Genomics, and Metabolism, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, USA
| | - Danai Veltra
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Nikolaos M Marinakis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Christalena Sofocleous
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Farah Ashrafzadeh
- Department of Pediatric Neurology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Davut Pehlivan
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children's Hospital, Houston, TX, USA
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Judith Melki
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR-1195, Université Paris Saclay, Le Kremlin Bicêtre, 94276, Paris, France
| | - Audrey Benezit
- Neurologie et réanimation pédiatrique, Hôpital Raymond Poincaré, APHP, Garches, France
| | - Peter Bauer
- CENTOGENE GmbH, Am Strande 7, 18055 Rostock, Germany
| | - Denisa Weis
- Department of Medical Genetics, Kepler University Hospital, Johann Kepler University, Linz, Austria
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Texas Children's Hospital, Houston, TX, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Jan Senderek
- Friedrich-Baur-Institute at the Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - John Christodoulou
- Discipline of Child and Adolescent Health, and Specialty of Genomic Medicine, Sydney Medical School, Sydney University, Sydney, NSW, Australia
- Murdoch Children's Research Institute, Melbourne and Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Wendy K Chung
- Department of Pediatrics and Medicine, Columbia University New York, NY, USA
| | - Rose Goodchild
- KU Leuven Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
- VIB-KU Leuven Center for Brain and Disease Research, Laboratory for Dystonia Research, Leuven, Belgium
| | - Amaka C Offiah
- Department of Oncology & Metabolism, University of Sheffield, UK
| | - Andres Moreno-De-Luca
- Autism & Developmental Medicine Institute, Genomic Medicine Institute, Department of Radiology, Diagnostic Medicine Institute, Geisinger, Danville, PA, USA
| | - Mohnish Suri
- Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Movement Disorders Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA
- Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Boston, MA, USA
| | - Henry Houlden
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, UK
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Abstract
PURPOSE OF REVIEW The discovery of new disease-causing genes and availability of next-generation sequencing platforms have both progressed rapidly over the last few years. For the practicing neurologist, this presents an increasingly bewildering array both of potential diagnoses and of means to investigate them. We review the latest newly described genetic conditions associated with dystonia, and also address how the changing landscape of gene discovery and genetic testing can best be approached, from both a research and a clinical perspective. RECENT FINDINGS Several new genetic causes for disorders in which dystonia is a feature have been described in the last 2 years, including ZNF142, GSX2, IRF2BPL, DEGS1, PI4K2A, CAMK4, VPS13D and VAMP2. Dystonia has also been a newly described feature or alternative phenotype of several other genetic conditions, notably for genes classically associated with several forms of epilepsy. The DYT system for classifying genetic dystonias, however, last recognized a new gene discovery (KMT2B) in 2016. SUMMARY Gene discovery for dystonic disorders proceeds rapidly, but a high proportion of cases remain undiagnosed. The proliferation of rare disorders means that it is no longer realistic for clinicians to aim for diagnosis to the level of predicting genotype from phenotype in all cases, but rational and adaptive use of available genetic tests can certainly expedite diagnosis.
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Ding B, Tang Y, Ma S, Akter M, Liu ML, Zang T, Zhang CL. Disease Modeling with Human Neurons Reveals LMNB1 Dysregulation Underlying DYT1 Dystonia. J Neurosci 2021; 41:2024-2038. [PMID: 33468570 PMCID: PMC7939088 DOI: 10.1523/jneurosci.2507-20.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 02/08/2023] Open
Abstract
DYT1 dystonia is a hereditary neurologic movement disorder characterized by uncontrollable muscle contractions. It is caused by a heterozygous mutation in Torsin A (TOR1A), a gene encoding a membrane-embedded ATPase. While animal models provide insights into disease mechanisms, significant species-dependent differences exist since animals with the identical heterozygous mutation fail to show pathology. Here, we model DYT1 by using human patient-specific cholinergic motor neurons (MNs) that are generated through either direct conversion of patients' skin fibroblasts or differentiation of induced pluripotent stem cells (iPSCs). These human MNs with the heterozygous TOR1A mutation show reduced neurite length and branches, markedly thickened nuclear lamina, disrupted nuclear morphology, and impaired nucleocytoplasmic transport (NCT) of mRNAs and proteins, whereas they lack the perinuclear "blebs" that are often observed in animal models. Furthermore, we uncover that the nuclear lamina protein LMNB1 is upregulated in DYT1 cells and exhibits abnormal subcellular distribution in a cholinergic MNs-specific manner. Such dysregulation of LMNB1 can be recapitulated by either ectopic expression of the mutant TOR1A gene or shRNA-mediated downregulation of endogenous TOR1A in healthy control MNs. Interestingly, downregulation of LMNB1 can largely ameliorate all the cellular defects in DYT1 MNs. These results reveal the value of disease modeling with human patient-specific neurons and indicate that dysregulation of LMNB1, a crucial component of the nuclear lamina, may constitute a major molecular mechanism underlying DYT1 pathology.SIGNIFICANCE STATEMENT Inaccessibility to patient neurons greatly impedes our understanding of the pathologic mechanisms for dystonia. In this study, we employ reprogrammed human patient-specific motor neurons (MNs) to model DYT1, the most severe hereditary form of dystonia. Our results reveal disease-dependent deficits in nuclear morphology and nucleocytoplasmic transport (NCT). Most importantly, we further identify LMNB1 dysregulation as a major contributor to these deficits, uncovering a new pathologic mechanism for DYT1 dystonia.
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Affiliation(s)
- Baojin Ding
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana 70503
| | - Yu Tang
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- National Clinical Research Center for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan Province 410008, China
| | - Shuaipeng Ma
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Masuma Akter
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana 70503
| | - Meng-Lu Liu
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Tong Zang
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Chun-Li Zhang
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Effect of Gabapentin in a Neuropathic Pain Model in Mice Overexpressing Human Wild-Type or Human Mutated Torsin A. Life (Basel) 2021; 11:life11010041. [PMID: 33445430 PMCID: PMC7826569 DOI: 10.3390/life11010041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND DYT1 dystonia is the most common form of early-onset inherited dystonia, which is caused by mutation of torsin A (TA) belonging to the "ATPases associated with a variety of cellular activities" (AAA + ATPase). Dystonia is often accompanied by pain, and neuropathic pain can be associated to peripherally induced movement disorder and dystonia. However, no evidence exists on the effect of gabapentin in mice subjected to neuropathic pain model overexpressing human normal or mutated TA. METHODS Mice subjected to L5 spinal nerve ligation (SNL) develop mechanical allodynia and upregulation of the α2δ-1 L-type calcium channel subunit, forming a validated experimental model of neuropathic pain. Under these experimental conditions, TA is expressed in dorsal horn neurons and astrocytes and colocalizes with α2δ-1. Similar to this subunit, TA is overexpressed in dorsal horn 7 days after SNL. This model has been used to investigate (1) basal mechanical sensitivity; (2) neuropathic pain phases; and (3) the effect of gabapentin, an α2δ-1 ligand used against neuropathic pain, in non-transgenic (NT) C57BL/6 mice and in mice overexpressing human wild-type (hWT) or mutant (hMT) TA. RESULTS In comparison to non-transgenic mice, the threshold for mechanical sensitivity in hWT or hMT does not differ (Kruskal-Wallis test = 1.478; p = 0.4777, although, in the latter animals, neuropathic pain recovery phase is delayed. Interestingly, gabapentin (100 mg/Kg) reduces allodynia at its peak (occurring between post-operative day 7 and day 10) but not in the phase of recovery. CONCLUSIONS These data lend support to the investigation on the role of TA in the molecular machinery engaged during neuropathic pain.
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Imbriani P, Ponterio G, Tassone A, Sciamanna G, El Atiallah I, Bonsi P, Pisani A. Models of dystonia: an update. J Neurosci Methods 2020; 339:108728. [PMID: 32289333 DOI: 10.1016/j.jneumeth.2020.108728] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/06/2020] [Accepted: 04/07/2020] [Indexed: 02/07/2023]
Abstract
Although dystonia represents the third most common movement disorder, its pathophysiology remains still poorly understood. In the past two decades, multiple models have been generated, improving our knowledge on the molecular and cellular bases of this heterogeneous group of movement disorders. In this short survey, we will focus on recently generated novel models of DYT1 dystonia, the most common form of genetic, "isolated" dystonia. These models clearly indicate the existence of multiple signaling pathways affected by the protein mutation causative of DYT1 dystonia, torsinA, paving the way for potentially multiple, novel targets for pharmacological intervention.
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Affiliation(s)
- P Imbriani
- Department of Systems Medicine, University of Rome "Tor Vergata", Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | - G Ponterio
- Department of Systems Medicine, University of Rome "Tor Vergata", Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | - A Tassone
- Department of Systems Medicine, University of Rome "Tor Vergata", Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | - G Sciamanna
- Department of Systems Medicine, University of Rome "Tor Vergata", Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | - I El Atiallah
- Department of Systems Medicine, University of Rome "Tor Vergata", Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | - P Bonsi
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - A Pisani
- Department of Systems Medicine, University of Rome "Tor Vergata", Italy; IRCCS Fondazione Santa Lucia, Rome, Italy.
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Gonzalez-Alegre P. Advances in molecular and cell biology of dystonia: Focus on torsinA. Neurobiol Dis 2019; 127:233-241. [DOI: 10.1016/j.nbd.2019.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/20/2019] [Accepted: 03/09/2019] [Indexed: 12/15/2022] Open
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Gill NK, Ly C, Kim PH, Saunders CA, Fong LG, Young SG, Luxton GWG, Rowat AC. DYT1 Dystonia Patient-Derived Fibroblasts Have Increased Deformability and Susceptibility to Damage by Mechanical Forces. Front Cell Dev Biol 2019; 7:103. [PMID: 31294022 PMCID: PMC6606767 DOI: 10.3389/fcell.2019.00103] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/27/2019] [Indexed: 12/24/2022] Open
Abstract
DYT1 dystonia is a neurological movement disorder that is caused by a loss-of-function mutation in the DYT1/TOR1A gene, which encodes torsinA, a conserved luminal ATPases-associated with various cellular activities (AAA+) protein. TorsinA is required for the assembly of functional linker of nucleoskeleton and cytoskeleton (LINC) complexes, and consequently the mechanical integration of the nucleus and the cytoskeleton. Despite the potential implications of altered mechanobiology in dystonia pathogenesis, the role of torsinA in regulating cellular mechanical phenotype, or mechanotype, in DYT1 dystonia remains unknown. Here, we define the deformability of mouse fibroblasts lacking functional torsinA as well as human fibroblasts isolated from DYT1 dystonia patients. We find that the deletion of torsinA or the expression of torsinA containing the DYT1 dystonia-causing ΔE302/303 (ΔE) mutation results in more deformable cells. We observe a similar increased deformability of mouse fibroblasts that lack lamina-associated polypeptide 1 (LAP1), which interacts with and stimulates the ATPase activity of torsinA in vitro, as well as with the absence of the LINC complex proteins, Sad1/UNC-84 1 (SUN1) and SUN2, lamin A/C, or lamin B1. Consistent with these findings, we also determine that DYT1 dystonia patient-derived fibroblasts are more compliant than fibroblasts isolated from unafflicted individuals. DYT1 dystonia patient-derived fibroblasts also exhibit increased nuclear strain and decreased viability following mechanical stretch. Taken together, our results establish the foundation for future mechanistic studies of the role of cellular mechanotype and LINC-dependent nuclear-cytoskeletal coupling in regulating cell survival following exposure to mechanical stresses.
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Affiliation(s)
- Navjot Kaur Gill
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Chau Ly
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Paul H Kim
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Cosmo A Saunders
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, United States
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, United States.,Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Amy C Rowat
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
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8
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Mitchell SB, Iwabuchi S, Kawano H, Yuen TMT, Koh JY, Ho KWD, Harata NC. Structure of the Golgi apparatus is not influenced by a GAG deletion mutation in the dystonia-associated gene Tor1a. PLoS One 2018; 13:e0206123. [PMID: 30403723 PMCID: PMC6221310 DOI: 10.1371/journal.pone.0206123] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/08/2018] [Indexed: 12/14/2022] Open
Abstract
Autosomal-dominant, early-onset DYT1 dystonia is associated with an in-frame deletion of a glutamic acid codon (ΔE) in the TOR1A gene. The gene product, torsinA, is an evolutionarily conserved AAA+ ATPase. The fact that constitutive secretion from patient fibroblasts is suppressed indicates that the ΔE-torsinA protein influences the cellular secretory machinery. However, which component is affected remains unclear. Prompted by recent reports that abnormal protein trafficking through the Golgi apparatus, the major protein-sorting center of the secretory pathway, is sometimes associated with a morphological change in the Golgi, we evaluated the influence of ΔE-torsinA on this organelle. Specifically, we examined its structure by confocal microscopy, in cultures of striatal, cerebral cortical and hippocampal neurons obtained from wild-type, heterozygous and homozygous ΔE-torsinA knock-in mice. In live neurons, the Golgi was assessed following uptake of a fluorescent ceramide analog, and in fixed neurons it was analyzed by immuno-fluorescence staining for the Golgi-marker GM130. Neither staining method indicated genotype-specific differences in the size, staining intensity, shape or localization of the Golgi. Moreover, no genotype-specific difference was observed as the neurons matured in vitro. These results were supported by a lack of genotype-specific differences in GM130 expression levels, as assessed by Western blotting. The Golgi was also disrupted by treatment with brefeldin A, but no genotype-specific differences were found in the immuno-fluorescence staining intensity of GM130. Overall, our results demonstrate that the ΔE-torsinA protein does not drastically influence Golgi morphology in neurons, irrespective of genotype, brain region (among those tested), or maturation stage in culture. While it remains possible that functional changes in the Golgi exist, our findings imply that any such changes are not severe enough to influence its morphology to a degree detectable by light microscopy.
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Affiliation(s)
- Sara B. Mitchell
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Sadahiro Iwabuchi
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Hiroyuki Kawano
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Tsun Ming Tom Yuen
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Department of Chemical and Biochemical Engineering, University of Iowa College of Engineering, Iowa City, Iowa, United States of America
| | - Jin-Young Koh
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - K. W. David Ho
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Medical Scientist Training Program, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - N. Charles Harata
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Medical Scientist Training Program, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- * E-mail:
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9
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Yu-Taeger L, Gaiser V, Lotzer L, Roenisch T, Fabry BT, Stricker-Shaver J, Casadei N, Walter M, Schaller M, Riess O, Nguyen HP, Ott T, Grundmann-Hauser K. Dynamic nuclear envelope phenotype in rats overexpressing mutated human torsinA protein. Biol Open 2018; 7:bio.032839. [PMID: 29739751 PMCID: PMC6078351 DOI: 10.1242/bio.032839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A three-base-pair deletion in the human TOR1A gene is causative for the most common form of primary dystonia: the early-onset dystonia type 1 (DYT1 dystonia). The pathophysiological consequences of this mutation are still unknown. To study the pathology of the mutant torsinA (TOR1A) protein, we have generated a transgenic rat line that overexpresses the human mutant protein under the control of the human TOR1A promoter. This new animal model was phenotyped with several approaches, including behavioral tests and neuropathological analyses. Motor phenotype, cellular and ultrastructural key features of torsinA pathology were found in this new transgenic rat line, supporting that it can be used as a model system for investigating the disease’s development. Analyses of mutant TOR1A protein expression in various brain regions also showed a dynamic expression pattern and a reversible nuclear envelope pathology. These findings suggest the differential vulnerabilities of distinct neuronal subpopulations. Furthermore, the reversibility of the nuclear envelope pathology might be a therapeutic target to treat the disease. Summary: A novel transgenic rat model displaying dystonia-like phenotypes and dynamic processes in NE pathology can become a useful tool for therapy development for dystonia and other related diseases.
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Affiliation(s)
- Libo Yu-Taeger
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Viktoria Gaiser
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Larissa Lotzer
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Tina Roenisch
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Core Facility Transgenic Animals, University Hospital Tuebingen, Otfried-Mueller-Str. 27, 72076 Tuebingen, Germany
| | - Benedikt Timo Fabry
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Janice Stricker-Shaver
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Nicolas Casadei
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Michael Walter
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Agilent Technologies, 5301 Stevens Creek Blvd, Santa Clara, CA 95051, USA
| | - Martin Schaller
- Department of Dermatology, University of Tuebingen, Liebermeisterstr. 25, 72076 Tuebingen, Germany
| | - Olaf Riess
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Huu Phuc Nguyen
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany .,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
| | - Thomas Ott
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Core Facility Transgenic Animals, University Hospital Tuebingen, Otfried-Mueller-Str. 27, 72076 Tuebingen, Germany
| | - Kathrin Grundmann-Hauser
- Institute for Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, Calwerstr. 7, 72076 Tuebingen, Germany
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10
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Mutations in THAP1/DYT6 reveal that diverse dystonia genes disrupt similar neuronal pathways and functions. PLoS Genet 2018; 14:e1007169. [PMID: 29364887 PMCID: PMC5798844 DOI: 10.1371/journal.pgen.1007169] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 02/05/2018] [Accepted: 12/25/2017] [Indexed: 12/14/2022] Open
Abstract
Dystonia is characterized by involuntary muscle contractions. Its many forms are genetically, phenotypically and etiologically diverse and it is unknown whether their pathogenesis converges on shared pathways. Mutations in THAP1 [THAP (Thanatos-associated protein) domain containing, apoptosis associated protein 1], a ubiquitously expressed transcription factor with DNA binding and protein-interaction domains, cause dystonia, DYT6. There is a unique, neuronal 50-kDa Thap1-like immunoreactive species, and Thap1 levels are auto-regulated on the mRNA level. However, THAP1 downstream targets in neurons, and the mechanism via which it causes dystonia are largely unknown. We used RNA-Seq to assay the in vivo effect of a heterozygote Thap1 C54Y or ΔExon2 allele on the gene transcription signatures in neonatal mouse striatum and cerebellum. Enriched pathways and gene ontology terms include eIF2α Signaling, Mitochondrial Dysfunction, Neuron Projection Development, Axonal Guidance Signaling, and Synaptic LongTerm Depression, which are dysregulated in a genotype and tissue-dependent manner. Electrophysiological and neurite outgrowth assays were consistent with those enrichments, and the plasticity defects were partially corrected by salubrinal. Notably, several of these pathways were recently implicated in other forms of inherited dystonia, including DYT1. We conclude that dysfunction of these pathways may represent a point of convergence in the pathophysiology of several forms of inherited dystonia. Dystonia is a brain disorder that causes disabling involuntary muscle contractions and abnormal postures. Mutations in THAP1, a zinc-finger transcription factor, cause DYT6, but its neuronal targets and functions are unknown. In this study, we sought to determine the effects of Thap1C54Y and ΔExon2 alleles on the gene transcription signatures at postnatal day 1 (P1) in the mouse striatum and cerebellum in order to correlate function with specific genes or pathways. Our unbiased transcriptomics approach showed that Thap1 mutants revealed multiple signaling pathways involved in neuronal plasticity, axonal guidance, and oxidative stress response, which are also present in other forms of dystonia, particularly DYT1. We conclude that dysfunction of these pathways may represent a point of convergence on the pathogenesis of unrelated forms of inherited dystonia.
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11
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Saunders CA, Harris NJ, Willey PT, Woolums BM, Wang Y, McQuown AJ, Schoenhofen A, Worman HJ, Dauer WT, Gundersen GG, Luxton GWG. TorsinA controls TAN line assembly and the retrograde flow of dorsal perinuclear actin cables during rearward nuclear movement. J Cell Biol 2017; 216:657-674. [PMID: 28242745 PMCID: PMC5350507 DOI: 10.1083/jcb.201507113] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/04/2016] [Accepted: 12/21/2016] [Indexed: 12/29/2022] Open
Abstract
The nucleus is positioned toward the rear of most migratory cells. In fibroblasts and myoblasts polarizing for migration, retrograde actin flow moves the nucleus rearward, resulting in the orientation of the centrosome in the direction of migration. In this study, we report that the nuclear envelope-localized AAA+ (ATPase associated with various cellular activities) torsinA (TA) and its activator, the inner nuclear membrane protein lamina-associated polypeptide 1 (LAP1), are required for rearward nuclear movement during centrosome orientation in migrating fibroblasts. Both TA and LAP1 contributed to the assembly of transmembrane actin-associated nuclear (TAN) lines, which couple the nucleus to dorsal perinuclear actin cables undergoing retrograde flow. In addition, TA localized to TAN lines and was necessary for the proper mobility of EGFP-mini-nesprin-2G, a functional TAN line reporter construct, within the nuclear envelope. Furthermore, TA and LAP1 were indispensable for the retrograde flow of dorsal perinuclear actin cables, supporting the recently proposed function for the nucleus in spatially organizing actin flow and cytoplasmic polarity. Collectively, these results identify TA as a key regulator of actin-dependent rearward nuclear movement during centrosome orientation.
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Affiliation(s)
- Cosmo A Saunders
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Nathan J Harris
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Patrick T Willey
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Brian M Woolums
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Yuexia Wang
- Department of Medicine, Columbia University, New York, NY 10032.,Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
| | - Alex J McQuown
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Amy Schoenhofen
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Howard J Worman
- Department of Medicine, Columbia University, New York, NY 10032.,Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
| | - William T Dauer
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109.,Department of Neurology, University of Michigan, Ann Arbor, MI 48109
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
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12
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Cascalho A, Jacquemyn J, Goodchild RE. Membrane defects and genetic redundancy: Are we at a turning point for DYT1 dystonia? Mov Disord 2016; 32:371-381. [PMID: 27911022 DOI: 10.1002/mds.26880] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/24/2016] [Accepted: 10/29/2016] [Indexed: 12/11/2022] Open
Abstract
Heterozygosity for a 3-base pair deletion (ΔGAG) in TOR1A/torsinA is one of the most common causes of hereditary dystonia. In this review, we highlight current understanding of how this mutation causes disease from research spanning structural biochemistry, cell science, neurobiology, and several model organisms. We now know that homozygosity for ΔGAG has the same effects as Tor1aKO , implicating a partial loss of function mechanism in the ΔGAG/+ disease state. In addition, torsinA loss specifically affects neurons in mice, even though the gene is broadly expressed, apparently because of differential expression of homologous torsinB. Furthermore, certain neuronal subtypes are more severely affected by torsinA loss. Interestingly, these include striatal cholinergic interneurons that display abnormal responses to dopamine in several Tor1a animal models. There is also progress on understanding torsinA molecular cell biology. The structural basis of how ΔGAG inhibits torsinA ATPase activity is defined, although mutant torsinAΔGAG protein also displays some characteristics suggesting it contributes to dystonia by a gain-of-function mechanism. Furthermore, a consistent relationship is emerging between torsin dysfunction and membrane biology, including an evolutionarily conserved regulation of lipid metabolism. Considered together, these findings provide major advances toward understanding the molecular, cellular, and neurobiological pathologies of DYT1/TOR1A dystonia that can hopefully be exploited for new approaches to treat this disease. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Ana Cascalho
- Vlaams Instituut voor Biotechnologie Centre for the Biology of Disease, Leuven, Belgium.,KU Leuven, Department of Human Genetics, Leuven, Belgium
| | - Julie Jacquemyn
- Vlaams Instituut voor Biotechnologie Centre for the Biology of Disease, Leuven, Belgium.,KU Leuven, Department of Human Genetics, Leuven, Belgium
| | - Rose E Goodchild
- Vlaams Instituut voor Biotechnologie Centre for the Biology of Disease, Leuven, Belgium.,KU Leuven, Department of Human Genetics, Leuven, Belgium
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13
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Bhagat SL, Qiu S, Caffall ZF, Wan Y, Pan Y, Rodriguiz RM, Wetsel WC, Badea A, Hochgeschwender U, Calakos N. Mouse model of rare TOR1A variant found in sporadic focal dystonia impairs domains affected in DYT1 dystonia patients and animal models. Neurobiol Dis 2016; 93:137-45. [PMID: 27168150 DOI: 10.1016/j.nbd.2016.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/25/2016] [Accepted: 05/05/2016] [Indexed: 12/13/2022] Open
Abstract
Rare de novo mutations in genes associated with inherited Mendelian disorders are potential contributors to sporadic disease. DYT1 dystonia is an autosomal dominant, early-onset, generalized dystonia associated with an in-frame, trinucleotide deletion (n. delGAG, p. ΔE 302/303) in the Tor1a gene. Here we examine the significance of a rare missense variant in the Tor1a gene (c. 613T>A, p. F205I), previously identified in a patient with sporadic late-onset focal dystonia, by modeling it in mice. Homozygous F205I mice have motor impairment, reduced steady-state levels of TorsinA, altered corticostriatal synaptic plasticity, and prominent brain imaging abnormalities in areas associated with motor function. Thus, the F205I variant causes abnormalities in domains affected in people and/or mouse models with the DYT1 Tor1a mutation (ΔE). Our findings establish the pathological significance of the F205I Tor1a variant and provide a model with both etiological and phenotypic relevance to further investigate dystonia mechanisms.
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Affiliation(s)
- Srishti L Bhagat
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States
| | - Sunny Qiu
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States
| | - Zachary F Caffall
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States
| | - Yehong Wan
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States
| | - Yuanji Pan
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States
| | - Ramona M Rodriguiz
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, United States
| | - William C Wetsel
- Duke Institute of Brain Sciences, United States; Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, United States
| | - Alexandra Badea
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, United States
| | - Ute Hochgeschwender
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States
| | - Nicole Calakos
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Duke Institute of Brain Sciences, United States.
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14
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Serrano JB, da Cruz E Silva OAB, Rebelo S. Lamina Associated Polypeptide 1 (LAP1) Interactome and Its Functional Features. MEMBRANES 2016; 6:membranes6010008. [PMID: 26784240 PMCID: PMC4812414 DOI: 10.3390/membranes6010008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/05/2016] [Accepted: 01/06/2016] [Indexed: 12/26/2022]
Abstract
Lamina-associated polypeptide 1 (LAP1) is a type II transmembrane protein of the inner nuclear membrane encoded by the human gene TOR1AIP1. LAP1 is involved in maintaining the nuclear envelope structure and appears be involved in the positioning of lamins and chromatin. To date, LAP1’s precise function has not been fully elucidated but analysis of its interacting proteins will permit unraveling putative associations to specific cellular pathways and cellular processes. By assessing public databases it was possible to identify the LAP1 interactome, and this was curated. In total, 41 interactions were identified. Several functionally relevant proteins, such as TRF2, TERF2IP, RIF1, ATM, MAD2L1 and MAD2L1BP were identified and these support the putative functions proposed for LAP1. Furthermore, by making use of the Ingenuity Pathways Analysis tool and submitting the LAP1 interactors, the top two canonical pathways were “Telomerase signalling” and “Telomere Extension by Telomerase” and the top functions “Cell Morphology”, “Cellular Assembly and Organization” and “DNA Replication, Recombination, and Repair”. Once again, putative LAP1 functions are reinforced but novel functions are emerging.
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Affiliation(s)
- Joana B Serrano
- Neuroscience and Signalling Laboratory, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Odete A B da Cruz E Silva
- Neuroscience and Signalling Laboratory, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Sandra Rebelo
- Neuroscience and Signalling Laboratory, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal.
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15
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Abstract
Torsin ATPases (Torsins) belong to the widespread AAA+ (ATPases associated with a variety of cellular activities) family of ATPases, which share structural similarity but have diverse cellular functions. Torsins are outliers in this family because they lack many characteristics of typical AAA+ proteins, and they are the only members of the AAA+ family located in the endoplasmic reticulum and contiguous perinuclear space. While it is clear that Torsins have essential roles in many, if not all metazoans, their precise cellular functions remain elusive. Studying Torsins has significant medical relevance since mutations in Torsins or Torsin-associated proteins result in a variety of congenital human disorders, the most frequent of which is early-onset torsion (DYT1) dystonia, a severe movement disorder. A better understanding of the Torsin system is needed to define the molecular etiology of these diseases, potentially enabling corrective therapy. Here, we provide a comprehensive overview of the Torsin system in metazoans, discuss functional clues obtained from various model systems and organisms and provide a phylogenetic and structural analysis of Torsins and their regulatory cofactors in relation to disease-causative mutations. Moreover, we review recent data that have led to a dramatically improved understanding of these machines at a molecular level, providing a foundation for investigating the molecular defects underlying the associated movement disorders. Lastly, we discuss our ideas on how recent progress may be utilized to inform future studies aimed at determining the cellular role(s) of these atypical molecular machines and their implications for dystonia treatment options.
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Affiliation(s)
- April E Rose
- a Department of Molecular Biophysics and Biochemistry , Yale University , New Haven , CT , USA and
| | - Rebecca S H Brown
- a Department of Molecular Biophysics and Biochemistry , Yale University , New Haven , CT , USA and
| | - Christian Schlieker
- a Department of Molecular Biophysics and Biochemistry , Yale University , New Haven , CT , USA and.,b Department of Cell Biology , Yale School of Medicine , New Haven , CT , USA
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16
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Cerebellar synaptogenesis is compromised in mouse models of DYT1 dystonia. Exp Neurol 2015; 271:457-67. [DOI: 10.1016/j.expneurol.2015.07.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/01/2015] [Accepted: 07/07/2015] [Indexed: 12/16/2022]
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17
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Kim AY, Seo JB, Kim WT, Choi HJ, Kim SY, Morrow G, Tanguay RM, Steller H, Koh YH. The pathogenic human Torsin A in Drosophila activates the unfolded protein response and increases susceptibility to oxidative stress. BMC Genomics 2015; 16:338. [PMID: 25903460 PMCID: PMC4415242 DOI: 10.1186/s12864-015-1518-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 04/10/2015] [Indexed: 01/11/2023] Open
Abstract
Background Dystonia1 (DYT1) dystonia is caused by a glutamic acid deletion (ΔE) mutation in the gene encoding Torsin A in humans (HTorA). To investigate the unknown molecular and cellular mechanisms underlying DYT1 dystonia, we performed an unbiased proteomic analysis. Results We found that the amount of proteins and transcripts of an Endoplasmic reticulum (ER) resident chaperone Heat shock protein cognate 3 (HSC3) and a mitochondria chaperone Heat Shock Protein 22 (HSP22) were significantly increased in the HTorAΔE– expressing brains compared to the normal HTorA (HTorAWT) expressing brains. The physiological consequences included an increased susceptibility to oxidative and ER stress compared to normal HTorAWT flies. The alteration of transcripts of Inositol-requiring enzyme-1 (IRE1)-dependent spliced X box binding protein 1(Xbp1), several ER chaperones, a nucleotide exchange factor, Autophagy related protein 8b (ATG8b) and components of the ER associated degradation (ERAD) pathway and increased expression of the Xbp1-enhanced Green Fluorescence Protein (eGFP) in HTorAΔE brains strongly indicated the activation of the unfolded protein response (UPR). In addition, perturbed expression of the UPR sensors and inducers in the HTorAΔEDrosophila brains resulted in a significantly reduced life span of the flies. Furthermore, the types and quantities of proteins present in the anti-HSC3 positive microsomes in the HTorAΔE brains were different from those of the HTorAWT brains. Conclusion Taken together, these data show that HTorAΔE in Drosophila brains may activate the UPR and increase the expression of HSP22 to compensate for the toxic effects caused by HTorAΔE in the brains. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1518-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- A-Young Kim
- ILSONG Institute of Life Science, Hallym University, 1605-4 Gwanyangdong, Dongan-gu, Anyang, Gyeonggido, 431-060, Republic of Korea. .,Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Gangwon-do, 200-702, Republic of Korea.
| | - Jong Bok Seo
- Korea Basic Science Institute, Sungbuk-gu, Seoul, 136-713, Republic of Korea.
| | - Won-Tae Kim
- National Academy of Agricultural Science, Rural Development Administration, Suwon, 441-707, Republic of Korea.
| | - Hee Jeong Choi
- ILSONG Institute of Life Science, Hallym University, 1605-4 Gwanyangdong, Dongan-gu, Anyang, Gyeonggido, 431-060, Republic of Korea. .,Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Gangwon-do, 200-702, Republic of Korea.
| | - Soo-Young Kim
- Korea Basic Science Institute, Sungbuk-gu, Seoul, 136-713, Republic of Korea.
| | - Genevieve Morrow
- Department of Molecular Biology, Medical Biochemistry & Pathology, Université Laval, Québec, Qc, G1V 0A6, Canada.
| | - Robert M Tanguay
- Department of Molecular Biology, Medical Biochemistry & Pathology, Université Laval, Québec, Qc, G1V 0A6, Canada.
| | - Hermann Steller
- Howard Hughes Medical Institute, the Rockefeller University, New York, NY, 10065, USA.
| | - Young Ho Koh
- ILSONG Institute of Life Science, Hallym University, 1605-4 Gwanyangdong, Dongan-gu, Anyang, Gyeonggido, 431-060, Republic of Korea. .,Department of Biomedical Gerontology, Graduate School of Hallym University, Chuncheon, Gangwon-do, 200-702, Republic of Korea.
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18
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LeDoux MS. Dystonia. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00024-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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19
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Cho JA, Zhang X, Miller GM, Lencer WI, Nery FC. 4-Phenylbutyrate attenuates the ER stress response and cyclic AMP accumulation in DYT1 dystonia cell models. PLoS One 2014; 9:e110086. [PMID: 25379658 PMCID: PMC4224384 DOI: 10.1371/journal.pone.0110086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/13/2014] [Indexed: 01/01/2023] Open
Abstract
Dystonia is a neurological disorder in which sustained muscle contractions induce twisting and repetitive movements or abnormal posturing. DYT1 early-onset primary dystonia is the most common form of hereditary dystonia and is caused by deletion of a glutamic acid residue (302/303) near the carboxyl-terminus of encoded torsinA. TorsinA is localized primarily within the contiguous lumen of the endoplasmic reticulum (ER) and nuclear envelope (NE), and is hypothesized to function as a molecular chaperone and an important regulator of the ER stress-signaling pathway, but how the mutation in torsinA causes disease remains unclear. Multiple lines of evidence suggest that the clinical symptoms of dystonia result from abnormalities in dopamine (DA) signaling, and possibly involving its down-stream effector adenylate cyclase that produces the second messenger cyclic adenosine-3', 5'-monophosphate (cAMP). Here we find that mutation in torsinA induces ER stress, and inhibits the cyclic adenosine-3', 5'-monophosphate (cAMP) response to the adenylate cyclase agonist forskolin. Both defective mechanins are corrected by the small molecule 4-phenylbutyrate (4-PBA) that alleviates ER stress. Our results link torsinA, the ER-stress-response, and cAMP-dependent signaling, and suggest 4-PBA could also be used in dystonia treatment. Other pharmacological agents known to modulate the cAMP cascade, and ER stress may also be therapeutic in dystonia patients and can be tested in the models described here, thus supplementing current efforts centered on the dopamine pathway.
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Affiliation(s)
- Jin A. Cho
- Division of Gastroenterology/Cell Biology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Xuan Zhang
- Neuroscience Center, Department of Neurology, and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, MA, United States of America
| | - Gregory M. Miller
- Department of Pharmaceutical Sciences and Center for Drug Discovery, Northeastern University, Boston, MA, United States of America
| | - Wayne I. Lencer
- Division of Gastroenterology/Cell Biology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States of America
- Harvard Digestive Diseases Center, Harvard Medical School, Boston, MA, United States of America
| | - Flavia C. Nery
- Neuroscience Center, Department of Neurology, and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, MA, United States of America
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20
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Vo A, Sako W, Dewey SL, Eidelberg D, Uluğ AM. 18FDG-microPET and MR DTI findings in Tor1a+/- heterozygous knock-out mice. Neurobiol Dis 2014; 73:399-406. [PMID: 25447231 DOI: 10.1016/j.nbd.2014.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/23/2014] [Accepted: 10/29/2014] [Indexed: 11/25/2022] Open
Abstract
TorsinA is an important protein in brain development, and plays a role in the regulation of neurite outgrowth and synaptic function. Patients with the most common form of genetic dystonia carry a mutation (DYT1) in one copy of the Tor1a gene, a 3-bp deletion, causing removal of a single glutamic acid from torsinA. Previous imaging studies have shown that abnormal cerebellar metabolism and damaged cerebello-thalamo-cortical pathway contribute to the pathophysiology of DYT1 dystonia. However, how a mutation in one copy of the Tor1a gene causes these abnormalities is not known. We studied Tor1a heterozygous knock-out mice in vivo with FDG-PET and ex vivo with diffusion tensor imaging. We found metabolic abnormalities in cerebellum, caudate-putamen, globus pallidus, sensorimotor cortex and subthalamic nucleus. We also found that FA was increased in caudate-putamen, sensorimotor cortex and brainstem. We compared our findings with a previous imaging study of the Tor1a knock-in mice. Our study suggested that having only one normal copy of Tor1a gene may be responsible for the metabolic abnormalities observed; having a copy of mutant Tor1a, on the other hand, may be responsible for white matter pathway damages seen in DYT1 dystonia subjects.
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Affiliation(s)
- An Vo
- Center for Neurosciences, The Feinstein Institute for Medical Research, NY 11030, USA
| | - Wataru Sako
- Center for Neurosciences, The Feinstein Institute for Medical Research, NY 11030, USA
| | - Stephen L Dewey
- Center for Neurosciences, The Feinstein Institute for Medical Research, NY 11030, USA; Department of Molecular Medicine, Hofstra University, NY 11549, USA; Department of Psychiatry, New York University, NY 10012, USA
| | - David Eidelberg
- Center for Neurosciences, The Feinstein Institute for Medical Research, NY 11030, USA
| | - Aziz M Uluğ
- Center for Neurosciences, The Feinstein Institute for Medical Research, NY 11030, USA; Department of Molecular Medicine, Hofstra University, NY 11549, USA; Department of Radiology, Albert Einstein College of Medicine, NY 10461, USA; Institute of Biomedical Engineering, Boğaziçi University, Istanbul, Turkey.
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21
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Harata NC. Current Gaps in the Understanding of the Subcellular Distribution of Exogenous and Endogenous Protein TorsinA. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2014; 4:260. [PMID: 25279252 PMCID: PMC4175402 DOI: 10.7916/d8js9nr2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 08/25/2014] [Indexed: 12/01/2022]
Abstract
Background An in-frame deletion leading to the loss of a single glutamic acid residue in the protein torsinA (ΔE-torsinA) results in an inherited movement disorder, DYT1 dystonia. This autosomal dominant disease affects the function of the brain without causing neurodegeneration, by a mechanism that remains unknown. Methods We evaluated the literature regarding the subcellular localization of torsinA. Results Efforts to elucidate the pathophysiological basis of DYT1 dystonia have relied partly on examining the subcellular distribution of the wild-type and mutated proteins. A typical approach is to introduce the human torsinA gene (TOR1A) into host cells and overexpress the protein therein. In both neurons and non-neuronal cells, exogenous wild-type torsinA introduced in this manner has been found to localize mainly to the endoplasmic reticulum, whereas exogenous ΔE-torsinA is predominantly in the nuclear envelope or cytoplasmic inclusions. Although these outcomes are relatively consistent, findings for the localization of endogenous torsinA have been variable, leaving its physiological distribution a matter of debate. Discussion As patients’ cells do not overexpress torsinA proteins, it is important to understand why the reported distributions of the endogenous proteins are inconsistent. We propose that careful optimization of experimental methods will be critical in addressing the causes of the differences among the distributions of endogenous (non-overexpressed) vs. exogenously introduced (overexpressed) proteins.
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Affiliation(s)
- N Charles Harata
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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22
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Hettich J, Ryan SD, de Souza ON, Saraiva Macedo Timmers LF, Tsai S, Atai NA, da Hora CC, Zhang X, Kothary R, Snapp E, Ericsson M, Grundmann K, Breakefield XO, Nery FC. Biochemical and cellular analysis of human variants of the DYT1 dystonia protein, TorsinA/TOR1A. Hum Mutat 2014; 35:1101-13. [PMID: 24930953 DOI: 10.1002/humu.22602] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 06/04/2014] [Indexed: 12/24/2022]
Abstract
Early-onset dystonia is associated with the deletion of one of a pair of glutamic acid residues (c.904_906delGAG/c.907_909delGAG; p.Glu302del/Glu303del; ΔE 302/303) near the carboxyl-terminus of torsinA, a member of the AAA(+) protein family that localizes to the endoplasmic reticulum lumen and nuclear envelope. This deletion commonly underlies early-onset DYT1 dystonia. While the role of the disease-causing mutation, torsinAΔE, has been established through genetic association studies, it is much less clear whether other rare human variants of torsinA are pathogenic. Two missense variations have been described in single patients: R288Q (c.863G>A; p.Arg288Gln; R288Q) identified in a patient with onset of severe generalized dystonia and myoclonus since infancy and F205I (c.613T>A, p.Phe205Ile; F205I) in a psychiatric patient with late-onset focal dystonia. In this study, we have undertaken a series of analyses comparing the biochemical and cellular effects of these rare variants to torsinAΔE and wild-type (wt) torsinA to reveal whether there are common dysfunctional features. The results revealed that the variants, R288Q and F205I, are more similar in their properties to torsinAΔE protein than to torsinAwt. These findings provide functional evidence for the potential pathogenic nature of these rare sequence variants in the TOR1A gene, thus implicating these pathologies in the development of dystonia.
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Affiliation(s)
- Jasmin Hettich
- Molecular Neurogenetics Unit, Department of Neurology and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts; Department of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany
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23
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Zacchi LF, Wu HC, Bell SL, Millen L, Paton AW, Paton JC, Thomas PJ, Zolkiewski M, Brodsky JL. The BiP molecular chaperone plays multiple roles during the biogenesis of torsinA, an AAA+ ATPase associated with the neurological disease early-onset torsion dystonia. J Biol Chem 2014; 289:12727-47. [PMID: 24627482 PMCID: PMC4007462 DOI: 10.1074/jbc.m113.529123] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 03/09/2014] [Indexed: 01/02/2023] Open
Abstract
Early-onset torsion dystonia (EOTD) is a neurological disorder characterized by involuntary and sustained muscle contractions that can lead to paralysis and abnormal posture. EOTD is associated with the deletion of a glutamate (ΔE) in torsinA, an endoplasmic reticulum (ER) resident AAA(+) ATPase. To date, the effect of ΔE on torsinA and the reason that this mutation results in EOTD are unclear. Moreover, there are no specific therapeutic options to treat EOTD. To define the underlying biochemical defects associated with torsinAΔE and to uncover factors that might be targeted to offset defects associated with torsinAΔE, we developed a yeast torsinA expression system and tested the roles of ER chaperones in mediating the folding and stability of torsinA and torsinAΔE. We discovered that the ER lumenal Hsp70, BiP, an associated Hsp40, Scj1, and a nucleotide exchange factor, Lhs1, stabilize torsinA and torsinAΔE. BiP also maintained torsinA and torsinAΔE solubility. Mutations predicted to compromise specific torsinA functional motifs showed a synthetic interaction with the ΔE mutation and destabilized torsinAΔE, suggesting that the ΔE mutation predisposes torsinA to defects in the presence of secondary insults. In this case, BiP was required for torsinAΔE degradation, consistent with data that specific chaperones exhibit either pro-degradative or pro-folding activities. Finally, using two independent approaches, we established that BiP stabilizes torsinA and torsinAΔE in mammalian cells. Together, these data define BiP as the first identified torsinA chaperone, and treatments that modulate BiP might improve symptoms associated with EOTD.
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Affiliation(s)
- Lucía F. Zacchi
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Hui-Chuan Wu
- the Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Samantha L. Bell
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Linda Millen
- the Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, and
| | - Adrienne W. Paton
- the Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - James C. Paton
- the Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Philip J. Thomas
- the Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, and
| | - Michal Zolkiewski
- the Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Jeffrey L. Brodsky
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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24
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Ledoux MS, Dauer WT, Warner TT. Emerging common molecular pathways for primary dystonia. Mov Disord 2014; 28:968-81. [PMID: 23893453 DOI: 10.1002/mds.25547] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 05/03/2013] [Accepted: 05/06/2013] [Indexed: 12/23/2022] Open
Abstract
The dystonias are a group of hyperkinetic movement disorders whose principal cause is neuron dysfunction at 1 or more interconnected nodes of the motor system. The study of genes and proteins that cause familial dystonia provides critical information about the cellular pathways involved in this dysfunction, which disrupts the motor pathways at the systems level. In recent years study of the increasing number of DYT genes has implicated a number of cell functions that appear to be involved in the pathogenesis of dystonia. A review of the literature published in English-language publications available on PubMed relating to the genetics and cellular pathology of dystonia was performed. Numerous potential pathogenetic mechanisms have been identified. We describe those that fall into 3 emerging thematic groups: cell-cycle and transcriptional regulation in the nucleus, endoplasmic reticulum and nuclear envelope function, and control of synaptic function. © 2013 Movement Disorder Society.
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Affiliation(s)
- Mark S Ledoux
- Department of Neurology, University of Tennessee Health Science Center Memphis, Tennessee 38163, USA
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25
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Dystonia as a network disorder: what is the role of the cerebellum? Neuroscience 2013; 260:23-35. [PMID: 24333801 DOI: 10.1016/j.neuroscience.2013.11.062] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 11/20/2013] [Accepted: 11/20/2013] [Indexed: 01/02/2023]
Abstract
The dystonias are a group of disorders defined by sustained or intermittent muscle contractions that result in involuntary posturing or repetitive movements. There are many different clinical manifestations and causes. Although they traditionally have been ascribed to dysfunction of the basal ganglia, recent evidence has suggested dysfunction may originate from other regions, particularly the cerebellum. This recent evidence has led to an emerging view that dystonia is a network disorder that involves multiple brain regions. The new network model for the pathogenesis of dystonia has raised many questions, particularly regarding the role of the cerebellum. For example, if dystonia may arise from cerebellar dysfunction, then why are there no cerebellar signs in dystonia? Why are focal cerebellar lesions or degenerative cerebellar disorders more commonly associated with ataxia rather than dystonia? Why is dystonia more commonly associated with basal ganglia lesions rather than cerebellar lesions? Can answers obtained from animals be extrapolated to humans? Is there any evidence that the cerebellum is not involved? Finally, what is the practical value of this new model of pathogenesis for the neuroscientist and clinician? This article explores potential answers to these questions.
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26
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Subtle microstructural changes of the cerebellum in a knock-in mouse model of DYT1 dystonia. Neurobiol Dis 2013; 62:372-80. [PMID: 24121114 DOI: 10.1016/j.nbd.2013.10.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 10/02/2013] [Indexed: 01/21/2023] Open
Abstract
The dystonias are a group of disorders characterized by involuntary twisting and repetitive movements. DYT1 dystonia is an inherited form of dystonia caused by a mutation in the TOR1A gene, which encodes torsinA. TorsinA is expressed in many regions of the nervous system, and the regions responsible for causing dystonic movements remain uncertain. Most prior studies have focused on the basal ganglia, although there is emerging evidence for abnormalities in the cerebellum too. In the current studies, we examined the cerebellum for structural abnormalities in a knock-in mouse model of DYT1 dystonia. The gross appearance of the cerebellum appeared normal in the mutant mice, but stereological measures revealed the cerebellum to be 5% larger in mutant compared to control mice. There were no changes in the numbers of Purkinje cells, granule cells, or neurons of the deep cerebellar nuclei. However, Golgi histochemical studies revealed Purkinje cells to have thinner dendrites, and fewer and less complex dendritic spines. There also was a higher frequency of heterotopic Purkinje cells displaced into the molecular layer. These results reveal subtle structural changes of the cerebellum that are similar to those reported for the basal ganglia in the DYT1 knock-in mouse model.
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Koh JY, Iwabuchi S, Harata NC. Dystonia-associated protein torsinA is not detectable at the nerve terminals of central neurons. Neuroscience 2013; 253:316-29. [PMID: 24025868 DOI: 10.1016/j.neuroscience.2013.08.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/28/2013] [Accepted: 08/28/2013] [Indexed: 01/23/2023]
Abstract
Presynaptic functions of the mammalian central neurons are regulated by a network of protein interactions. Synaptic vesicle recycling in and neurotransmitter release from the presynaptic nerve terminals are altered when a glutamate-deleting mutation is present in the torsinA protein (ΔE-torsinA). This mutation is linked with a hereditary form of the movement disorder dystonia known as DYT1 dystonia. Although torsinA expression is prevalent throughout the central nervous system, its subcellular localization - in particular with respect to presynaptic nerve terminals - remains unclear. This information would be useful in narrowing down possible models for how wild-type torsinA affects presynaptic function, as well as the nature of the presynaptic dysfunction that arises in the context of ΔE-torsinA mutation. Here we report on an analysis of the presynaptic localization of torsinA in cultured neurons obtained from a knock-in mouse model of DYT1 dystonia. Primary cultures of neurons were established from heterozygous and homozygous ΔE-torsinA knock-in mice, as well as from their wild-type littermates. Neurons were obtained from the striatum, cerebral cortex and hippocampus of these mice, and were subjected to immunocytochemistry. This analysis revealed the expression of both proteins in the somata and dendrites. However, neither the nerve terminals nor axonal shafts were immunoreactive. These results were confirmed by fluorogram-based quantitation. Our findings indicate that neither the wild-type nor the ΔE-torsinA mutant protein is present at substantial levels in the presynaptic structures of cultured neurons. Thus, the effects of torsinA, in wild-type and mutant forms, appear to influence presynaptic function indirectly, without residing in presynaptic structures.
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Affiliation(s)
- J-Y Koh
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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28
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Kawarai T, Miyamoto R, Murakami N, Miyazaki Y, Koizumi H, Sako W, Mukai Y, Sato K, Matsumoto S, Sakamoto T, Izumi Y, Kaji R. [Dystonia genes and elucidation of their roles in dystonia pathogenesis]. Rinsho Shinkeigaku 2013; 53:419-29. [PMID: 23782819 DOI: 10.5692/clinicalneurol.53.419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Identification of causative genes for hereditary dystonia and elucidation of their functions are crucial for better understanding of dystonia pathogenesis. As seen in other hereditary neurologic disorders, intra- and inter-familial clinical variations have been demonstrated in hereditary dystonia. Asymptomatic carriers can be found due to alterations in penetrance, generally reduced in succeeding generations. Current known dystonia genes include those related to dopamine metabolism, transcription factor, cytoskeleton, transport of glucose and sodium ion, etc. It has been reported that effects of deep brain stimulation can vary significantly depending on genotype. Accumulation of genotype-outcome correlations would contribute to treatment decisions for dystonia patients.
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Affiliation(s)
- Toshitaka Kawarai
- Department of Clinical Neuroscience Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima
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29
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Puglisi F, Vanni V, Ponterio G, Tassone A, Sciamanna G, Bonsi P, Pisani A, Mandolesi G. Torsin A Localization in the Mouse Cerebellar Synaptic Circuitry. PLoS One 2013; 8:e68063. [PMID: 23840813 PMCID: PMC3686744 DOI: 10.1371/journal.pone.0068063] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 05/24/2013] [Indexed: 11/19/2022] Open
Abstract
Torsin A (TA) is a ubiquitous protein belonging to the superfamily of proteins called "ATPases associated with a variety of cellular activities" (AAA(+) ATPase). To date, a great deal of attention has been focused on neuronal TA since its mutant form causes early-onset (DYT1) torsion dystonia, an inherited movement disorder characterized by sustained muscle contractions and abnormal postures. Interestingly, it has been proposed that TA, by interacting with the cytoskeletal network, may contribute to the control of neurite outgrowth and/or by acting as a chaperone at synapses could affect synaptic vesicle turnover and neurotransmitter release. Accordingly, both its peculiar developmental expression in striatum and cerebellum and evidence from DYT1 knock-in mice suggest that TA may influence dendritic arborization and synaptogenesis in the brain. Therefore, to better understand TA function a detailed description of its localization at synaptic level is required. Here, we characterized by means of rigorous quantitative confocal analysis TA distribution in the mouse cerebellum at postnatal day 14 (P14), when both cerebellar synaptogenesis and TA expression peak. We observed that the protein is broadly distributed both in cerebellar cortex and in the deep cerebellar nuclei (DCN). Of note, Purkinje cells (PC) express high levels of TA also in the spines and axonal terminals. In addition, abundant expression of the protein was found in the main GABA-ergic and glutamatergic inputs of the cerebellar cortex. Finally, TA was observed also in glial cells, a cellular population little explored so far. These results extend our knowledge on TA synaptic localization providing a clue to its potential role in synaptic development.
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Affiliation(s)
- Francesca Puglisi
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
| | - Valentina Vanni
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
| | - Giulia Ponterio
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
| | - Annalisa Tassone
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
| | - Giuseppe Sciamanna
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
| | - Paola Bonsi
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
| | - Antonio Pisani
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
- * E-mail:
| | - Georgia Mandolesi
- Department of Systems Medicine, University of Rome Tor Vergata/Laboratory of Neurophysiology and Synaptic Plasticity, Fondazione Santa Lucia, Rome, Italy
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Abstract
Dystonia is a common movement disorder seen by neurologists in clinic. Genetic forms of the disease are important to recognize clinically and also provide valuable information about possible pathogenic mechanisms within the wider disorder. In the past few years, with the advent of new sequencing technologies, there has been a step change in the pace of discovery in the field of dystonia genetics. In just over a year, four new genes have been shown to cause primary dystonia (CIZ1, ANO3, TUBB4A and GNAL), PRRT2 has been identified as the cause of paroxysmal kinesigenic dystonia and other genes, such as SLC30A10 and ATP1A3, have been linked to more complicated forms of dystonia or new phenotypes. In this review, we provide an overview of the current state of knowledge regarding genetic forms of dystonia—related to both new and well-known genes alike—and incorporating genetic, clinical and molecular information. We discuss the mechanistic insights provided by the study of the genetic causes of dystonia and provide a helpful clinical algorithm to aid clinicians in correctly predicting the genetic basis of various forms of dystonia.
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Affiliation(s)
- Gavin Charlesworth
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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Hersheson J, Mencacci NE, Davis M, MacDonald N, Trabzuni D, Ryten M, Pittman A, Paudel R, Kara E, Fawcett K, Plagnol V, Bhatia KP, Medlar AJ, Stanescu HC, Hardy J, Kleta R, Wood NW, Houlden H. Mutations in the autoregulatory domain of β-tubulin 4a cause hereditary dystonia. Ann Neurol 2013; 73:546-53. [PMID: 23424103 PMCID: PMC3698699 DOI: 10.1002/ana.23832] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Revised: 10/23/2012] [Accepted: 11/05/2012] [Indexed: 12/24/2022]
Abstract
Dystonia type 4 (DYT4) was first described in a large family from Heacham in Norfolk with an autosomal dominantly inherited whispering dysphonia, generalized dystonia, and a characteristic hobby horse ataxic gait. We carried out a genetic linkage analysis in the extended DYT4 family that spanned 7 generations from England and Australia, revealing a single LOD score peak of 6.33 on chromosome 19p13.12-13. Exome sequencing in 2 cousins identified a single cosegregating mutation (p.R2G) in the β-tubulin 4a (TUBB4a) gene that was absent in a large number of controls. The mutation is highly conserved in the β-tubulin autoregulatory MREI (methionine-arginine-glutamic acid-isoleucine) domain, highly expressed in the central nervous system, and extensive in vitro work has previously demonstrated that substitutions at residue 2, specifically R2G, disrupt the autoregulatory capability of the wild-type β-tubulin peptide, affirming the role of the cytoskeleton in dystonia pathogenesis.
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Affiliation(s)
- Joshua Hersheson
- Department of Molecular Neuroscience, University College London Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom
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32
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Abstract
Dystonia has been defined as a syndrome of involuntary, sustained muscle contractions affecting one or more sites of the body, frequently causing twisting and repetitive movements or abnormal postures. Dystonia is also a clinical sign that can be the presenting or prominent manifestation of many neurodegenerative and neurometabolic disorders. Etiological categories include primary dystonia, secondary dystonia, heredodegenerative diseases with dystonia, and dystonia plus. Primary dystonia includes syndromes in which dystonia is the sole phenotypic manifestation with the exception that tremor can be present as well. Most primary dystonia begins in adults, and approximately 10% of probands report one or more affected family members. Many cases of childhood- and adolescent-onset dystonia are due to mutations in TOR1A and THAP1. Mutations in THAP1 and CIZ1 have been associated with sporadic and familial adult-onset dystonia. Although significant recent progress had been made in defining the genetic basis for most of the dystonia-plus and heredodegenerative diseases with dystonia, a major gap remains in understanding the genetic etiologies for most cases of adult-onset primary dystonia. Common themes in the cellular biology of dystonia include G1/S cell cycle control, monoaminergic neurotransmission, mitochondrial dysfunction, and the neuronal stress response.
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Affiliation(s)
- Mark S LeDoux
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN, USA
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33
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Abstract
PURPOSE OF REVIEW This review considers the recent literature pertaining to the clinical features, genetics, neuropathology and treatment of dystonia syndromes. RECENT FINDINGS The term dystonia indicates at the same time a clinical phenotype and a collection of neurological syndromes mainly of genetic origin. The physical signs contributing to the phenomenology of dystonia have been recently assembled into a coherent set. The molecular genetics of primary dystonia syndromes (DYT1 and DYT6) have been the object of extensive analysis, providing converging views on their causative mechanisms. The relationship between genotype, phenotype, and endophenotypes has been explored for hereditary and sporadic dystonia syndromes. Neurophysiological studies on DYT1 and DYT6 patients, as well as on nonmanifesting carriers, have demonstrated the presence of altered synaptic plasticity. Several recent data indicate a role of dopamine and acetylcholine (ACh) transmission in the pathophysiology of primary dystonia. SUMMARY Recent findings have led to novel, testable hypotheses on cellular mechanisms and physiopathological abnormalities underlying dystonia. Neurophysiological studies, imaging data and animal models support the view that corticostriatal, cerebellar, and dopaminergic dysfunctions converge to produce the pathophysiological abnormalities of dystonia.
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Li X, Lee J, Parsons D, Janaurajs K, Standaert DG. Evaluation of TorsinA as a target for Parkinson disease therapy in mouse models. PLoS One 2012; 7:e50063. [PMID: 23185535 PMCID: PMC3503809 DOI: 10.1371/journal.pone.0050063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 10/18/2012] [Indexed: 11/19/2022] Open
Abstract
Parkinson disease (PD) is a common and disabling disorder. No current therapy can slow or reverse disease progression. An important aspect of research in this field is target validation, a systematic approach to evaluating the likelihood that modification of a certain molecule, mechanism or biological pathway may be useful for the development of pharmacological or molecular treatments for the disease. TorsinA, a member of the AAA+ family of chaperone proteins, has been proposed as a potential target of neuroprotective therapy. TorsinA is found in Lewy bodies in human PD, and can suppress toxicity in cellular and invertebrate models of PD. Here, we evaluated the neuroprotective properties of torsinA in mouse models of PD based on intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as well as recombinant adeno associated virus (rAAV) induced overexpression of alpha-synuclein (α-syn). Using either transgenic mice with overexpression of human torsinA (hWT mice) or mice in which torsinA expression was induced using an rAAV vector, we found no evidence for protection against acute MPTP intoxication. Similarly, genetic deletion of the endogenous mouse gene for torsinA (Dyt1) using an rAAV delivered Cre recombinase did not enhance the vulnerability of dopaminergic neurons to MPTP. Overexpression of α-syn using rAAV in the mouse substantia nigra lead to a loss of TH positive neurons six months after administration, and no difference in the degree of loss was observed between transgenic animals expressing forms of torsinA and wild type controls. Collectively, we did not observe evidence for a protective effect of torsinA in the mouse models we examined. Each of these models has limitations, and there is no single model with established predictive value with respect to the human disease. Nevertheless, these data do seem to support the view that torsinA is unlikely to be successfully translated as a target of therapy for human PD.
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Affiliation(s)
- Xinru Li
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jenny Lee
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Dee Parsons
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Karen Janaurajs
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - David G. Standaert
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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The zebrafish homologue of the human DYT1 dystonia gene is widely expressed in CNS neurons but non-essential for early motor system development. PLoS One 2012; 7:e45175. [PMID: 23028827 PMCID: PMC3460957 DOI: 10.1371/journal.pone.0045175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/17/2012] [Indexed: 11/19/2022] Open
Abstract
DYT1 dystonia is caused by mutation of the TOR1A gene, resulting in the loss of a single glutamic acid residue near the carboxyl terminal of TorsinA. The neuronal functions perturbed by TorsinA[ΔE] are a major unresolved issue in understanding the pathophysiology of dystonia, presenting a critical roadblock to developing effective treatments. We identified and characterized the zebrafish homologue of TOR1A, as a first step towards elucidating the functions of TorsinA in neurons, in vivo, using the genetically-manipulable zebrafish model. The zebrafish genome was found to contain a single alternatively-spliced tor1 gene, derived from a common ancestral locus shared with the dual TOR1A and TOR1B paralogues found in tertrapods. tor1 was expressed ubiquitously during early embryonic development and in multiple adult tissues, including the CNS. The 2.1 kb tor1 mRNA encodes Torsin1, which is 59% identical and 78% homologous to human TorsinA. Torsin1 was expressed as major 45 kDa and minor 47 kDa glycoproteins, within the cytoplasm of neurons and neuropil throughout the CNS. Similar to previous findings relating to human TorsinA, mutations of the ATP hydrolysis domain of Torsin1 resulted in relocalization of the protein in cultured cells from the endoplasmic reticulum to the nuclear envelope. Zebrafish embryos lacking tor1 during early development did not show impaired viability, overt morphological abnormalities, alterations in motor behavior, or developmental defects in the dopaminergic system. Torsin1 is thus non-essential for early development of the motor system, suggesting that important CNS functions may occur later in development, consistent with the critical time window in late childhood when dystonia symptoms usually emerge in DYT1 patients. The similarities between Torsin1 and human TorsinA in domain organization, expression pattern, and cellular localization suggest that the zebrafish will provide a useful model to understand the neuronal functions of Torsins in vivo.
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Untethering the nuclear envelope and cytoskeleton: biologically distinct dystonias arising from a common cellular dysfunction. Int J Cell Biol 2012; 2012:634214. [PMID: 22611399 PMCID: PMC3352338 DOI: 10.1155/2012/634214] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 12/12/2011] [Accepted: 01/08/2012] [Indexed: 12/31/2022] Open
Abstract
Most cases of early onset DYT1 dystonia in humans are caused by a GAG deletion in the TOR1A gene leading to loss of a glutamic acid (ΔE) in the torsinA protein, which underlies a movement disorder associated with neuronal dysfunction without apparent neurodegeneration. Mutation/deletion of the gene (Dst) encoding dystonin in mice results in a dystonic movement disorder termed dystonia musculorum, which resembles aspects of dystonia in humans. While torsinA and dystonin proteins do not share modular domain architecture, they participate in a similar function by modulating a structural link between the nuclear envelope and the cytoskeleton in neuronal cells. We suggest that through a shared interaction with the nuclear envelope protein nesprin-3α, torsinA and the neuronal dystonin-a2 isoform comprise a bridge complex between the outer nuclear membrane and the cytoskeleton, which is critical for some aspects of neuronal development and function. Elucidation of the overlapping roles of torsinA and dystonin-a2 in nuclear/endoplasmic reticulum dynamics should provide insights into the cellular mechanisms underlying the dystonic phenotype.
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Fernández-Alvarez E, Nardocci N. Update on pediatric dystonias: etiology, epidemiology, and management. Degener Neurol Neuromuscul Dis 2012; 2:29-41. [PMID: 30890876 DOI: 10.2147/dnnd.s16082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Dystonia is a movement disorder characterized by sustained muscle contractions producing twisting, repetitive, and patterned movements or abnormal postures. Dystonia is among the most commonly observed movement disorders in clinical practice both in adults and children. It is classified on the basis of etiology, age at onset of symptoms, and distribution of affected body regions. Etiology The etiology of pediatric dystonia is quite heterogeneous. There are many different genetic syndromes and several causes of symptomatic syndromes. Dystonia can be secondary to virtually any pathological process that affects the motor system, and particularly the basal ganglia. Classification The etiological classification distinguishes primary dystonia with no identifiable exogenous cause or evidence of neurodegeneration and secondary syndromes. Treatment Treatment for most forms of dystonia is symptomatic and includes drugs (systemic or focal treatments, such as botulinum toxin) and surgical procedures. There are several medications including anticholinergic, dopamine-blocking and depleting agents, baclofen, and benzodiazepines. In patients with dopamine synthesis defects L-dopa treatment may be very useful. Botulinum toxin treatment may be helpful in controlling the most disabling symptoms of segmental or focal dystonia. Long-term electrical stimulation of the globus pallidum internum appears to be especially successful in children suffering from generalized dystonia.
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Affiliation(s)
| | - Nardo Nardocci
- Child Neurology Department, Fondazione IRCCS Istituto Neurologico "C. Besta", Milano, Italy
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38
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Grundmann K, Glöckle N, Martella G, Sciamanna G, Hauser TK, Yu L, Castaneda S, Pichler B, Fehrenbacher B, Schaller M, Nuscher B, Haass C, Hettich J, Yue Z, Nguyen HP, Pisani A, Riess O, Ott T. Generation of a novel rodent model for DYT1 dystonia. Neurobiol Dis 2012; 47:61-74. [PMID: 22472189 DOI: 10.1016/j.nbd.2012.03.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 03/13/2012] [Accepted: 03/17/2012] [Indexed: 10/28/2022] Open
Abstract
A mutation in the coding region of the Tor1A gene, resulting in a deletion of a glutamic acid residue in the torsinA protein (∆ETorA), is the major cause of the inherited autosomal-dominant early onset torsion dystonia (DYT1). The pathophysiological consequences of this amino acid loss are still not understood. Currently available animal models for DYT1 dystonia provided important insights into the disease; however, they differ with respect to key features of torsinA associated pathology. We developed transgenic rat models harboring the full length human mutant and wildtype Tor1A gene. A complex phenotyping approach including classical behavioral tests, electrophysiology and neuropathology revealed a progressive neurological phenotype in ∆ETorA expressing rats. Furthermore, we were able to replicate key pathological features of torsinA associated pathology in a second species, such as nuclear envelope pathology, behavioral abnormalities and plasticity changes. We therefore suggest that this rat model represents an appropriate new model suitable to further investigate the pathophysiology of ∆ETorA and to test for therapeutic approaches.
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Abstract
The last 25 years have seen remarkable advances in our understanding of the genetic etiologies of dystonia, new approaches into dissecting underlying pathophysiology, and independent progress in identifying effective treatments. In this review we highlight some of these advances, especially the genetic findings that have taken us from phenomenological to molecular-based diagnoses. Twenty DYT loci have been designated and 10 genes identified, all based on linkage analyses in families. Hand in hand with these genetic findings, neurophysiological and imaging techniques have been employed that have helped illuminate the similarities and differences among the various etiological dystonia subtypes. This knowledge is just beginning to yield new approaches to treatment including those based on DYT1 animal models. Despite the lag in identifying genetically based therapies, effective treatments, including impressive benefits from deep brain stimulation and botulinum toxin chemodenervation, have marked the last 25 years. The challenge ahead includes continued advancement into understanding dystonia's many underlying causes and associated pathology and using this knowledge to advance treatment including preventing genetic disease expression.
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Affiliation(s)
- Laurie J Ozelius
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, USA
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40
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Nery FC, Armata IA, Farley JE, Cho JA, Yaqub U, Chen P, da Hora CC, Wang Q, Tagaya M, Klein C, Tannous B, Caldwell KA, Caldwell GA, Lencer WI, Ye Y, Breakefield XO. TorsinA participates in endoplasmic reticulum-associated degradation. Nat Commun 2011; 2:393. [PMID: 21750546 PMCID: PMC3529909 DOI: 10.1038/ncomms1383] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 06/08/2011] [Indexed: 11/09/2022] Open
Abstract
TorsinA is an AAA+ ATPase located within the lumen of the endoplasmic reticulum and nuclear envelope, with a mutant form causing early onset torsion dystonia (DYT1). Here we report a new function for torsinA in endoplasmic reticulum-associated degradation (ERAD). Retro-translocation and proteosomal degradation of a mutant cystic fibrosis transmembrane conductance regulator (CFTRΔF508) was inhibited by downregulation of torsinA or overexpression of mutant torsinA, and facilitated by increased torsinA. Retro-translocation of cholera toxin was also decreased by downregulation of torsinA. TorsinA associates with proteins implicated in ERAD, including Derlin-1, VIMP, and p97. Further, torsinA reduces endoplasmic reticulum stress in nematodes overexpressing CFTRΔF508, and fibroblasts from DYT1 dystonia patients are more sensitive than controls to endoplasmic reticulum stress and less able to degrade mutant CFTR. Therefore, compromised ERAD function in the cells of DYT1 patients may increase sensitivity to endoplasmic reticulum stress with consequent alterations in neuronal function contributing to the disease state.
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Affiliation(s)
- Flávia C Nery
- 1] Neuroscience Center, Department of Neurology, and Center for Molecular Imaging Research, Department of Radiology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02114, USA. [2]
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41
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Robottom BJ, Weiner WJ, Comella CL. Early-onset primary dystonia. HANDBOOK OF CLINICAL NEUROLOGY 2011; 100:465-79. [PMID: 21496603 DOI: 10.1016/b978-0-444-52014-2.00036-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
"Dystonia" is the term used to describe abnormal movements consisting of sustained muscle contractions frequently causing twisting and repetitive movements or abnormal postures. Dystonia is classified partly by age at onset because this helps guide the diagnostic work-up and treatment decisions. This chapter focuses on early-onset (<26 years old) primary dystonia. The history, clinical features, genetics, pathophysiology, diagnosis, and treatment of early-onset primary dystonia are discussed. Special emphasis is placed on DYT1 dystonia, the most common, autosomal-dominant, early-onset, primary dystonia. A diagnostic algorithm is proposed for gene-negative early-onset dystonia, and treatment recommendations for generalized, early-onset dystonia are made.
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Affiliation(s)
- Bradley J Robottom
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA
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42
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Zhang L, Yokoi F, Jin YH, DeAndrade MP, Hashimoto K, Standaert DG, Li Y. Altered dendritic morphology of Purkinje cells in Dyt1 ΔGAG knock-in and purkinje cell-specific Dyt1 conditional knockout mice. PLoS One 2011; 6:e18357. [PMID: 21479250 PMCID: PMC3066238 DOI: 10.1371/journal.pone.0018357] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Accepted: 02/28/2011] [Indexed: 11/18/2022] Open
Abstract
Background DYT1 early-onset generalized dystonia is a neurological movement disorder characterized by involuntary muscle contractions. It is caused by a trinucleotide deletion of a GAG (ΔGAG) in the DYT1 (TOR1A) gene encoding torsinA; the mouse homolog of this gene is Dyt1 (Tor1a). Although structural and functional alterations in the cerebellum have been reported in DYT1 dystonia, neuronal morphology has not been examined in vivo. Methodology/Principal Findings In this study, we examined the morphology of the cerebellum in Dyt1 ΔGAG knock-in (KI) mice. Golgi staining of the cerebellum revealed a reduction in the length of primary dendrites and a decrease in the number of spines on the distal dendrites of Purkinje cells. To determine if this phenomenon was cell autonomous and mediated by a loss of torsinA function in Purkinje cells, we created a knockout of the Dyt1 gene only in Purkinje cells of mice. We found the Purkinje-cell specific Dyt1 conditional knockout (Dyt1 pKO) mice have similar alterations in Purkinje cell morphology, with shortened primary dendrites and decreased spines on the distal dendrites. Conclusion/Significance These results suggest that the torsinA is important for the proper development of the cerebellum and a loss of this function in the Purkinje cells results in an alteration in dendritic structure.
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Affiliation(s)
- Lin Zhang
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Fumiaki Yokoi
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Yuan-Hu Jin
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Mark P. DeAndrade
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
| | - David G. Standaert
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Yuqing Li
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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43
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Genetics and Pharmacological Treatment of Dystonia. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011. [DOI: 10.1016/b978-0-12-381328-2.00019-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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44
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Ezquerra M, Compta Y, Marti MJ. Identifying the genetic components underlying the pathophysiology of movement disorders. APPLICATION OF CLINICAL GENETICS 2011; 4:81-92. [PMID: 23776369 PMCID: PMC3681180 DOI: 10.2147/tacg.s7333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Movement disorders are a heterogeneous group of neurological conditions, few of which have been classically described as bona fide hereditary illnesses (Huntington’s chorea, for instance). Most are considered to be either sporadic or to feature varying degrees of familial aggregation (parkinsonism and dystonia). In the late twentieth century, Mendelian monogenic mutations were found for movement disorders with a clear and consistent family history. Although important, these findings apply only to very rare forms of movement disorders. Already in the twenty-first century, and taking advantage of the modern developments in genetics and molecular biology, growing attention is being paid to the complex genetics of movement disorders. The search for risk genetic variants (polymorphisms) in large cohorts and the identification of different risk variants across different populations and ethnic groups are under way, with the most relevant findings to date corresponding to recent genome wide association studies in Parkinson’s disease. These new approaches focusing on risk variants may enable the design of screening tests for early or even preclinical disease, and the identification of likely therapeutic targets.
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Affiliation(s)
- Mario Ezquerra
- Parkinson's Disease and Movement Disorders Unit, Service of Neurology, Institute of Clinical Neurosciences, Hospital Clinic of Barcelona, IDIBAPS, CIBERNED, Spain
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45
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Genetic and clinical features of primary torsion dystonia. Neurobiol Dis 2010; 42:127-35. [PMID: 21168499 DOI: 10.1016/j.nbd.2010.12.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/08/2010] [Accepted: 12/10/2010] [Indexed: 12/31/2022] Open
Abstract
Primary torsion dystonia (PTD) is defined as a syndrome in which dystonia is the only clinical sign (except for tremor), and there is no evidence of neuronal degeneration or an acquired cause by history or routine laboratory assessment. Seven different loci have been recognized for PTD but only two of the genes have been identified. In this review we will describe the phenotypes associated with these loci and discuss the responsible gene. This article is part of a Special Issue entitled "Advances in dystonia".
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46
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CSN complex controls the stability of selected synaptic proteins via a torsinA-dependent process. EMBO J 2010; 30:181-93. [PMID: 21102408 DOI: 10.1038/emboj.2010.285] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Accepted: 10/20/2010] [Indexed: 11/08/2022] Open
Abstract
DYT1 dystonia is caused by an autosomal dominant mutation that leads to a glutamic acid deletion in torsinA (TA), a member of the AAA+ ATPase superfamily. In this study, we identified a novel-binding partner of TA, the subunit 4 (CSN4) of CSN signalosome. TA binds CSN4 and the synaptic regulator snapin in neuroblastoma cells and in brain synaptosomes. CSN4 and TA are required for the stability of both snapin and the synaptotagmin-specific endocytic adaptor stonin 2, as downregulation of CSN4 or TA reduces the levels of both proteins. Snapin is phosphorylated by the CSN-associated kinase protein kinase D (PKD) and its expression is decreased upon PKD inhibition. In contrast, the stability of stonin 2 is regulated by neddylation, another CSN-associated activity. Overexpression of the pathological TA mutant (ΔE-TA) reduces stonin 2 expression, causing the accumulation of the calcium sensor synaptotagmin 1 on the cell surface. Retrieval of surface-stranded synaptotagmin 1 is restored by overexpression of stonin 2 in ΔE-TA-expressing cells, suggesting that the DYT1 mutation compromises the role of TA in protein stabilisation and synaptic vesicle recycling.
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47
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Abstract
BACKGROUND Impaired cortical inhibiton and maladaptive cortical plasticity are functional hallmarks of sporadic focal dystonias. Whether or not these mechanisms translate to generalized dystonias and whether these features reflect state or trait characteristics are topics of research in hereditary dystonias. METHODS We present a series of studies using a multitracer approach with positron emission tomography (PET) and diffusion tensor MRI (DTI) in the DYT1 and the DYT6 genotype. RESULTS In these hereditary dystonias functional and microstructural abnormalities were found in cortico-striatal-pallido-thalamocortical (CSPTC) and cerebellar-thalamo-cortical circuits. Genotype-specific abnormalities were localized to the basal ganglia, SMA and cerebellum. Functional changes, as potential correlates of maladaptive sensorimotor plasticity were found throughout the sensorimotor system and were more pronounced in affected mutation carriers than in their non-manifesting counterparts. In both genotypes, striatal metabolic abnormalities were paralleled by genotype-specific reductions in D(2) receptor availability. However, these reductions failed to show a clear association with clinical or functional markers of the disease. By contrast, microstructural changes of cerebellar pathways clearly related to penetrance and may thus represent the main intrinsic abnormality underlying cortical downstream effects, such as increased sensorimotor responsivity. CONCLUSIONS These studies are consistent with the view of primary torsion dystonia as a neurodevelopmental circuit disorder involving CSPTC and related cerebellar pathways.
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Affiliation(s)
- M Carbon
- Center for Neurosciences, The Feinstein Institute for Medical Research, North Shore - Long Island Jewish Health System, Manhasset, NY 11030, USA.
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48
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Zhu L, Millen L, Mendoza JL, Thomas PJ. A unique redox-sensing sensor II motif in TorsinA plays a critical role in nucleotide and partner binding. J Biol Chem 2010; 285:37271-80. [PMID: 20861018 DOI: 10.1074/jbc.m110.123471] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Early onset dystonia is commonly associated with the deletion of one of a pair of glutamate residues (ΔE302/303) near the C terminus of torsinA, a member of the AAA+ protein family (ATPases associated with a variety of cellular activities) located in the endoplasmic reticulum lumen. The functional consequences of the disease-causing mutation, ΔE, are not currently understood. By contrast to other AAA+ proteins, torsin proteins contain two conserved cysteine residues in the C-terminal domain, one of which is located in the nucleotide sensor II motif. Depending on redox status, an ATP hydrolysis mutant of torsinA interacts with lamina-associated polypeptide 1 (LAP1) and lumenal domain like LAP1 (LULL1). Substitution of the cysteine in sensor II diminishes the redox-regulated interaction of torsinA with these substrates. Significantly, the dystonia-causing mutation, ΔE, alters the ability of torsinA to mediate the redox-regulated interactions with LAP1 and LULL1. Limited proteolysis experiments reveal redox- and mutation-dependent changes in the local conformation of torsinA as a function of nucleotide binding. These results indicate that the cysteine-containing sensor II plays a critical role in redox sensing and the nucleotide and partner binding functions of torsinA and suggest that loss of this function of torsinA contributes to the development of DYT1 dystonia.
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Affiliation(s)
- Li Zhu
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Texas 75390, USA
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Chen P, Burdette AJ, Porter JC, Ricketts JC, Fox SA, Nery FC, Hewett JW, Berkowitz LA, Breakefield XO, Caldwell KA, Caldwell GA. The early-onset torsion dystonia-associated protein, torsinA, is a homeostatic regulator of endoplasmic reticulum stress response. Hum Mol Genet 2010; 19:3502-15. [PMID: 20584926 DOI: 10.1093/hmg/ddq266] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Early-onset torsion dystonia is the most severe heritable form of dystonia, a human movement disorder that typically starts during a developmental window in early adolescence. Deletion in the DYT1 gene, encoding the torsinA protein, is responsible for this dominantly inherited disorder, which is non-degenerative and exhibits reduced penetrance among carriers. Here, we explore the hypothesis that deficits in torsinA function result in an increased vulnerability to stress associated with protein folding and processing in the endoplasmic reticulum (ER), where torsinA is located. Using an in vivo quantitative readout for the ER stress response, we evaluated the consequences of torsinA mutations in transgenic nematodes expressing variants of human torsinA. This analysis revealed that, normally, torsinA serves a protective function to maintain a homeostatic threshold against ER stress. Furthermore, we show that the buffering capacity of torsinA is greatly diminished by the DYT1-associated deletion or mutations that prevent its translocation to the ER, block ATPase activity, or increase the levels of torsinA in the nuclear envelope versus ER. Combinations of transgenic Caenorhabditis elegans designed to mimic clinically relevant genetic modifiers of disease susceptibility also exhibit a direct functional correlation to changes in the ER stress response. Furthermore, using mouse embryonic fibroblasts (MEFs) from torsinA knockout mice, we demonstrated that loss of endogenous torsinA results in enhanced sensitivity to ER stress. This study extends our understanding of molecular mechanisms underlying dystonia, and establishes a new functional paradigm to evaluate therapeutic strategies to compensate for reduced torsinA activity in the ER as a means to restore homeostatic balance and neuronal function.
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Affiliation(s)
- Pan Chen
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
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Valente EM, Albanese A. Advances in the genetics of primary torsion dystonia. F1000 BIOLOGY REPORTS 2010; 2. [PMID: 20948792 PMCID: PMC2950024 DOI: 10.3410/b2-41] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Knowledge about the genetics of primary torsion dystonia (PTD) has been progressing at a very slow pace compared with other movement disorders. For many years, only one causative gene was known, DYT1/TOR1A, yet the recent identification of a second PTD causative gene (DYT6/THAP1), the detection of subclinical alterations caused by mutations in PTD genes in some healthy non-penetrant individuals, and functional studies on TOR1A and THAP1 protein products have significantly improved mutation detection, genotype-phenotype correlates, and our understanding of the cellular mechanisms underlying the development of dystonia.
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