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Hadjiosif AM, Gibo TL, Smith MA. The cerebellum acts as the analog to the medial temporal lobe for sensorimotor memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.11.553008. [PMID: 38645006 PMCID: PMC11030252 DOI: 10.1101/2023.08.11.553008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The cerebellum is critical for sensorimotor learning. The specific contribution that it makes, however, remains unclear. Inspired by the classic finding that, for declarative memories, medial temporal lobe structures provide a gateway to the formation of long-term memory but are not required for short-term memory, we hypothesized that, for sensorimotor memories, the cerebellum may play an analogous role. Here we studied the sensorimotor learning of individuals with severe ataxia from cerebellar degeneration. We dissected the memories they formed during sensorimotor learning into a short-term temporally-volatile component, that decays rapidly with a time constant of just 15-20sec and thus cannot lead to long-term retention, and a longer-term temporally-persistent component that is stable for 60 sec or more and leads to long-term retention. Remarkably, we find that these individuals display dramatically reduced levels of temporally-persistent sensorimotor memory, despite spared and even elevated levels of temporally-volatile sensorimotor memory. In particular, we find both impairment that systematically increases with memory window duration over shorter memory windows (<12 sec) and near-complete impairment of memory maintenance over longer memory windows (>25 sec). This dissociation uncovers a new role for the cerebellum as a gateway for the formation of long-term but not short-term sensorimotor memories, mirroring the role of the medial temporal lobe for declarative memories. It thus reveals the existence of distinct neural substrates for short-term and long-term sensorimotor memory, and it explains both newly-identified trial-to-trial differences and long-standing study-to-study differences in the effects of cerebellar damage on sensorimotor learning ability. Significance Statement A key discovery about the neural underpinnings of memory, made more than half a century ago, is that long-term, but not short-term, memory formation depends on neural structures in the brain's medial temporal lobe (MTL). However, this dichotomy holds only for declarative memories - memories for explicit facts such as names and dates - as long-term procedural memories - memories for implicit knowledge such as sensorimotor skills - are largely unaffected even with substantial MTL damage. Here we demonstrate that the formation of long-term, but not short-term, sensorimotor memory depends on a neural structure known as the cerebellum, and we show that this finding explains the variability previously reported in the extent to which cerebellar damage affects sensorimotor learning.
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Scaravilli A, Tranfa M, Pontillo G, Brais B, De Michele G, La Piana R, Saccà F, Santorelli FM, Synofzik M, Brunetti A, Cocozza S. CHARON: An Imaging-Based Diagnostic Algorithm to Navigate Through the Sea of Hereditary Degenerative Ataxias. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01677-y. [PMID: 38436911 DOI: 10.1007/s12311-024-01677-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/23/2024] [Indexed: 03/05/2024]
Abstract
The complexity in diagnosing hereditary degenerative ataxias lies not only in their rarity, but also in the variety of different genetic conditions that can determine sometimes similar and overlapping clinical findings. In this light, Magnetic Resonance Imaging (MRI) plays a key role in the evaluation of these conditions, being a fundamental diagnostic tool needed not only to exclude other causes determining the observed clinical phenotype, but also to proper guide to an adequate genetic testing. Here, we propose an MRI-based diagnostic algorithm named CHARON (Characterization of Hereditary Ataxias Relying On Neuroimaging), to help in disentangling among the numerous, and apparently very similar, hereditary degenerative ataxias. Being conceived from a neuroradiological standpoint, it is based primarily on an accurate evaluation of the observed MRI findings, with the first and most important being the pattern of cerebellar atrophy. Along with the evaluation of the presence, or absence, of additional signal changes and/or supratentorial involvement, CHARON allows for the identification of a small groups of ataxias sharing similar imaging features. The integration of additional MRI findings, demographic, clinical and laboratory data allow then for the identification of typical, and in some cases pathognomonic, phenotypes of hereditary ataxias.
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Affiliation(s)
- Alessandra Scaravilli
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Naples, Italy
| | - Mario Tranfa
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Naples, Italy
| | - Giuseppe Pontillo
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Naples, Italy
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Canada
| | - Giovanna De Michele
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Canada
| | - Francesco Saccà
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | | | - Matthis Synofzik
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Division Translational Genomics of Neurodegenerative Diseases, Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Arturo Brunetti
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Naples, Italy
| | - Sirio Cocozza
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Naples, Italy.
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3
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Kumar M, Tyagi N, Faruq M. The molecular mechanisms of spinocerebellar ataxias for DNA repeat expansion in disease. Emerg Top Life Sci 2023; 7:289-312. [PMID: 37668011 DOI: 10.1042/etls20230013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 09/06/2023]
Abstract
Spinocerebellar ataxias (SCAs) are a heterogenous group of neurodegenerative disorders which commonly inherited in an autosomal dominant manner. They cause muscle incoordination due to degeneration of the cerebellum and other parts of nervous system. Out of all the characterized (>50) SCAs, 14 SCAs are caused due to microsatellite repeat expansion mutations. Repeat expansions can result in toxic protein gain-of-function, protein loss-of-function, and/or RNA gain-of-function effects. The location and the nature of mutation modulate the underlying disease pathophysiology resulting in varying disease manifestations. Potential toxic effects of these mutations likely affect key major cellular processes such as transcriptional regulation, mitochondrial functioning, ion channel dysfunction and synaptic transmission. Involvement of several common pathways suggests interlinked function of genes implicated in the disease pathogenesis. A better understanding of the shared and distinct molecular pathogenic mechanisms in these diseases is required to develop targeted therapeutic tools and interventions for disease management. The prime focus of this review is to elaborate on how expanded 'CAG' repeats contribute to the common modes of neurotoxicity and their possible therapeutic targets in management of such devastating disorders.
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Affiliation(s)
- Manish Kumar
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
| | - Nishu Tyagi
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
| | - Mohammed Faruq
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
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4
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Yonenobu Y, Beck G, Kido K, Maeda N, Yamashita R, Inoue K, Saito Y, Hasegawa M, Ito H, Hasegawa K, Morii E, Iwaki T, Murayama S, Mochizuki H. Neuropathology of spinocerebellar ataxia type 8: Common features and unique tauopathy. Neuropathology 2023; 43:351-361. [PMID: 36703300 DOI: 10.1111/neup.12894] [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: 10/12/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/28/2023]
Abstract
Spinocerebellar ataxia type 8 (SCA8) is a neurodegenerative condition that presents with several neurological symptoms, such as cerebellar ataxia, parkinsonism, and cognitive impairment. It is caused by a CTA/CTG repeat expansion on chromosome 13q21 (ataxin 8 opposite strand [ATXN8OS]). However, the pathological significance of this expansion remains unclear. Moreover, abnormal CTA/CTG repeat expansions in ATXN8OS have also been reported in other neurodegenerative diseases, including progressive supranuclear palsy. In this study, we analyzed all available autopsy cases in Japan to investigate common pathological features and profiles of tau pathology in each case. Severe neuronal loss in the substantia nigra and prominent loss of Purkinje cells, atrophy of the molecular layer, and proliferation of Bergmann glia in the cerebellum were common features. Regarding tauopathy, one case presented with progressive supranuclear palsy-like 4-repeat tauopathy in addition to mild Alzheimer-type 3- and 4-repeat tauopathy. Another case showed 3- and 4-repeat tauopathy accentuated in the brainstem. The other two cases lacked tauopathy after extensive immunohistochemical studies. The present study confirmed common pathological features of SCA8 as degeneration of the substantia nigra in addition to the cerebellum. Our study also confirmed unique tauopathy in two of four cases, indicating the necessity to further collect autopsy cases.
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Affiliation(s)
- Yuki Yonenobu
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Goichi Beck
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kansuke Kido
- Department of Pathology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Norihisa Maeda
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Rika Yamashita
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kimiko Inoue
- Department of Neurology and Rehabilitation Medicine, National Hospital Organization, Osaka Toneyama Medical Center, Toyonaka, Japan
| | - Yuko Saito
- Department of Neurology and Neuropathology (Brain Bank for Aging Research), Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hidefumi Ito
- Department of Neurology, Wakayama Medical University, Wakayama City, Japan
| | - Kazuko Hasegawa
- Department of Neurology, National Hospital Organization, Sagamihara National Hospital, Sagamihara, Japan
| | - Eiichi Morii
- Department of Pathology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Toru Iwaki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shigeo Murayama
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
- Department of Neurology and Neuropathology (Brain Bank for Aging Research), Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
- Brain Bank for Neurodevelopmental, Neurological and Psychiatric Disorders, Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, Suita, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
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5
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Simona K, Veronika M, Zahinoor I, Martin V. Neuropsychiatric symptoms in spinocerebellar ataxias and Friedreich ataxia. Neurosci Biobehav Rev 2023; 150:105205. [PMID: 37137435 DOI: 10.1016/j.neubiorev.2023.105205] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 04/14/2023] [Accepted: 04/29/2023] [Indexed: 05/05/2023]
Abstract
Apart from its role in motor coordination, the importance of the cerebellum in cognitive and affective processes has been recognized in the past few decades. Spinocerebellar ataxias (SCA) and Friedreich ataxia (FRDA) are rare neurodegenerative diseases of the cerebellum presenting mainly with a progressive loss of gait and limb coordination, dysarthria, and other motor disturbances, but also a range of cognitive and neuropsychiatric symptoms. This narrative review summarizes the current knowledge on neuropsychiatric impairment in SCA and FRDA. We discuss the prevalence, clinical features and treatment approaches in the most commonly reported domains of depression, anxiety, apathy, agitation and impulse dyscontrol, and psychosis. Since these symptoms have a considerable impact on patients' quality of life, we argue that further research is mandated to improve the detection and treatment options of neuropsychiatric co-morbidities in ataxia patients.
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Affiliation(s)
- Karamazovova Simona
- Center of Hereditary Ataxias, Department of Neurology, 2nd Faculty of Medicine and Motol University Hospital, Charles University, Prague, Czech Republic
| | - Matuskova Veronika
- Center of Hereditary Ataxias, Department of Neurology, 2nd Faculty of Medicine and Motol University Hospital, Charles University, Prague, Czech Republic.
| | - Ismail Zahinoor
- Departments of Psychiatry, Clinical Neurosciences, and Community Health Sciences, Cumming School of Medicine; Hotchkiss Brain Institute and O'Brien Institute of Public Health, University of Calgary, Calgary, Alberta, Canada
| | - Vyhnalek Martin
- Center of Hereditary Ataxias, Department of Neurology, 2nd Faculty of Medicine and Motol University Hospital, Charles University, Prague, Czech Republic
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Braun M, Shoshani S, Teixeira J, Mellul Shtern A, Miller M, Granot Z, Fischer SE, Garcia SMA, Tabach Y. Asymmetric inheritance of RNA toxicity in C. elegans expressing CTG repeats. iScience 2022; 25:104246. [PMID: 35494247 PMCID: PMC9051633 DOI: 10.1016/j.isci.2022.104246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/01/2022] [Accepted: 04/07/2022] [Indexed: 11/18/2022] Open
Abstract
Nucleotide repeat expansions are a hallmark of over 40 neurodegenerative diseases and cause RNA toxicity and multisystemic symptoms that worsen with age. Through an unclear mechanism, RNA toxicity can trigger severe disease manifestation in infants if the repeats are inherited from their mother. Here we use Caenorhabditis elegans bearing expanded CUG repeats to show that this asymmetric intergenerational inheritance of toxicity contributes to disease pathogenesis. In addition, we show that this mechanism is dependent on small RNA pathways with maternal repeat-derived small RNAs causing transcriptomic changes in the offspring, reduced motility, and shortened lifespan. We rescued the toxicity phenotypes in the offspring by perturbing the RNAi machinery in the affected hermaphrodites. This points to a novel mechanism linking maternal bias and the RNAi machinery and suggests that toxic RNA is transmitted to offspring, causing disease phenotypes through intergenerational epigenetic inheritance. Maternal origin of expanded CUG repeats induces RNA toxicity in Caenorhabditis elegans offspring Offspring of affected hermaphrodites show molecular and phenotypic disease phenotypes The RNAi machinery is directly related to the maternal inheritance of RNA toxicity Altering the RNAi machinery in affected hermaphrodites rescues toxicity in offspring
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Affiliation(s)
- Maya Braun
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Shachar Shoshani
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Joana Teixeira
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790 Finland
| | - Anna Mellul Shtern
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Maya Miller
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Zvi Granot
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Sylvia E.J. Fischer
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Susana M.D. A. Garcia
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790 Finland
- Corresponding author
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Corresponding author
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7
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Corral-Juan M, Casquero P, Giraldo-Restrepo N, Laurie S, Martinez-Piñeiro A, Mateo-Montero RC, Ispierto L, Vilas D, Tolosa E, Volpini V, Alvarez-Ramo R, Sánchez I, Matilla-Dueñas A. OUP accepted manuscript. Brain Commun 2022; 4:fcac030. [PMID: 35310830 PMCID: PMC8928420 DOI: 10.1093/braincomms/fcac030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/20/2021] [Accepted: 02/08/2022] [Indexed: 11/18/2022] Open
Abstract
Spinocerebellar ataxias consist of a highly heterogeneous group of inherited movement disorders clinically characterized by progressive cerebellar ataxia variably associated with additional distinctive clinical signs. The genetic heterogeneity is evidenced by the myriad of associated genes and underlying genetic defects identified. In this study, we describe a new spinocerebellar ataxia subtype in nine members of a Spanish five-generation family from Menorca with affected individuals variably presenting with ataxia, nystagmus, dysarthria, polyneuropathy, pyramidal signs, cerebellar atrophy and distinctive cerebral demyelination. Affected individuals presented with horizontal and vertical gaze-evoked nystagmus and hyperreflexia as initial clinical signs, and a variable age of onset ranging from 12 to 60 years. Neurophysiological studies showed moderate axonal sensory polyneuropathy with altered sympathetic skin response predominantly in the lower limbs. We identified the c.1877C > T (p.Ser626Leu) pathogenic variant within the SAMD9L gene as the disease causative genetic defect with a significant log-odds score (Zmax = 3.43; θ = 0.00; P < 3.53 × 10−5). We demonstrate the mitochondrial location of human SAMD9L protein, and its decreased levels in patients’ fibroblasts in addition to mitochondrial perturbations. Furthermore, mutant SAMD9L in zebrafish impaired mobility and vestibular/sensory functions. This study describes a novel spinocerebellar ataxia subtype caused by SAMD9L mutation, SCA49, which triggers mitochondrial alterations pointing to a role of SAMD9L in neurological motor and sensory functions.
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Affiliation(s)
- Marc Corral-Juan
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
| | - Pilar Casquero
- Neurology and Neurophysiology Section, Hospital Mateu Orfila, Mahón, Menorca, Spain
| | | | - Steve Laurie
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Alicia Martinez-Piñeiro
- Neuromuscular and Functional Studies Unit, Neurology Service, University Hospital Germans Trias i Pujol (HUGTiP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
| | | | - Lourdes Ispierto
- Neurodegenerative Diseases Unit, Neurology Service, Department of Neuroscience, University Hospital Germans Trias i Pujol (HUGTiP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
| | - Dolores Vilas
- Neurodegenerative Diseases Unit, Neurology Service, Department of Neuroscience, University Hospital Germans Trias i Pujol (HUGTiP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
- Parkinson Disease and Movement Disorders Unit, Neurology Service, Hospital Clínic de Barcelona, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona (UB), Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED: CB06/05/0018-ISCIII), Barcelona, Spain
| | - Eduardo Tolosa
- Parkinson Disease and Movement Disorders Unit, Neurology Service, Hospital Clínic de Barcelona, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona (UB), Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED: CB06/05/0018-ISCIII), Barcelona, Spain
| | | | - Ramiro Alvarez-Ramo
- Neurodegenerative Diseases Unit, Neurology Service, Department of Neuroscience, University Hospital Germans Trias i Pujol (HUGTiP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
| | - Ivelisse Sánchez
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
| | - Antoni Matilla-Dueñas
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona-Can Ruti Campus, Badalona, Barcelona, Spain
- Correspondence to: Dr Antoni Matilla-Dueñas Head of the Neurogenetics Unit Health Sciences Research Institute Germans Trias i Pujol (IGTP) Ctra. de Can Ruti, Camí de les Escoles s/n 08916 Badalona, Barcelona, Spain E-mail:
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Perez BA, Shorrock HK, Banez‐Coronel M, Zu T, Romano LEL, Laboissonniere LA, Reid T, Ikeda Y, Reddy K, Gomez CM, Bird T, Ashizawa T, Schut LJ, Brusco A, Berglund JA, Hasholt LF, Nielsen JE, Subramony SH, Ranum LPW. CCG•CGG interruptions in high-penetrance SCA8 families increase RAN translation and protein toxicity. EMBO Mol Med 2021; 13:e14095. [PMID: 34632710 PMCID: PMC8573593 DOI: 10.15252/emmm.202114095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 12/28/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8), a dominantly inherited neurodegenerative disorder caused by a CTG•CAG expansion, is unusual because most individuals that carry the mutation do not develop ataxia. To understand the variable penetrance of SCA8, we studied the molecular differences between highly penetrant families and more common sporadic cases (82%) using a large cohort of SCA8 families (n = 77). We show that repeat expansion mutations from individuals with multiple affected family members have CCG•CGG interruptions at a higher frequency than sporadic SCA8 cases and that the number of CCG•CGG interruptions correlates with age at onset. At the molecular level, CCG•CGG interruptions increase RNA hairpin stability, and in cell culture experiments, increase p-eIF2α and polyAla and polySer RAN protein levels. Additionally, CCG•CGG interruptions, which encode arginine interruptions in the polyGln frame, increase toxicity of the resulting proteins. In summary, SCA8 CCG•CGG interruptions increase polyAla and polySer RAN protein levels, polyGln protein toxicity, and disease penetrance and provide novel insight into the molecular differences between SCA8 families with high vs. low disease penetrance.
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Affiliation(s)
- Barbara A Perez
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Hannah K Shorrock
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Monica Banez‐Coronel
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Tao Zu
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Lisa EL Romano
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Lauren A Laboissonniere
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Tammy Reid
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Yoshio Ikeda
- Department of NeurologyGunma UniversityMaebashiJapan
| | - Kaalak Reddy
- RNA InstituteUniversity at Albany–SUNYAlbanyNYUSA
| | | | - Thomas Bird
- Department of NeurologyUniversity of WashingtonSeattleWAUSA
- Geriatrics Research SectionVA Puget Sound Health Care SystemSeattleWAUSA
| | - Tetsuo Ashizawa
- Department of NeurologyHouston Methodist Research InstituteHoustonTXUSA
| | | | - Alfredo Brusco
- Department of Medical SciencesUniversity of TorinoTorinoItaly
- Medical Genetics Units“Città della Salute e della Scienza” University HospitalTorinoItaly
| | - J Andrew Berglund
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- RNA InstituteUniversity at Albany–SUNYAlbanyNYUSA
| | - Lis F Hasholt
- Institute of Cellular and Molecular MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Jorgen E Nielsen
- Department of NeurologyRigshospitaletUniversity of CopenhagenCopenhagenDenmark
| | - SH Subramony
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- McKnight Brain InstituteUniversity of FloridaGainesvilleFLUSA
| | - Laura PW Ranum
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
- McKnight Brain InstituteUniversity of FloridaGainesvilleFLUSA
- Genetics InstituteUniversity of FloridaGainesvilleFLUSA
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9
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Cocozza S, Pontillo G, De Michele G, Di Stasi M, Guerriero E, Perillo T, Pane C, De Rosa A, Ugga L, Brunetti A. Conventional MRI findings in hereditary degenerative ataxias: a pictorial review. Neuroradiology 2021; 63:983-999. [PMID: 33733696 PMCID: PMC8213578 DOI: 10.1007/s00234-021-02682-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 02/25/2021] [Indexed: 12/15/2022]
Abstract
Purpose Cerebellar ataxias are a large and heterogeneous group of disorders. The evaluation of brain parenchyma via MRI plays a central role in the diagnostic assessment of these conditions, being mandatory to exclude the presence of other underlying causes in determining the clinical phenotype. Once these possible causes are ruled out, the diagnosis is usually researched in the wide range of hereditary or sporadic ataxias. Methods We here propose a review of the main clinical and conventional imaging findings of the most common hereditary degenerative ataxias, to help neuroradiologists in the evaluation of these patients. Results Hereditary degenerative ataxias are all usually characterized from a neuroimaging standpoint by the presence, in almost all cases, of cerebellar atrophy. Nevertheless, a proper assessment of imaging data, extending beyond the mere evaluation of cerebellar atrophy, evaluating also the pattern of volume loss as well as concomitant MRI signs, is crucial to achieve a proper diagnosis. Conclusion The integration of typical neuroradiological characteristics, along with patient’s clinical history and laboratory data, could allow the neuroradiologist to identify some conditions and exclude others, addressing the neurologist to the more appropriate genetic testing.
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Affiliation(s)
- Sirio Cocozza
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy.
| | - Giuseppe Pontillo
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy.,Department of Electrical Engineering and Information Technology, University of Naples "Federico II", Naples, Italy
| | - Giovanna De Michele
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | - Martina Di Stasi
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy
| | - Elvira Guerriero
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy
| | - Teresa Perillo
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy
| | - Chiara Pane
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | - Anna De Rosa
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | - Lorenzo Ugga
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy
| | - Arturo Brunetti
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini, 5, 80131, Naples, Italy
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10
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Antisense Transcription across Nucleotide Repeat Expansions in Neurodegenerative and Neuromuscular Diseases: Progress and Mysteries. Genes (Basel) 2020; 11:genes11121418. [PMID: 33261024 PMCID: PMC7760973 DOI: 10.3390/genes11121418] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Unstable repeat expansions and insertions cause more than 30 neurodegenerative and neuromuscular diseases. Remarkably, bidirectional transcription of repeat expansions has been identified in at least 14 of these diseases. More remarkably, a growing number of studies has been showing that both sense and antisense repeat RNAs are able to dysregulate important cellular pathways, contributing together to the observed clinical phenotype. Notably, antisense repeat RNAs from spinocerebellar ataxia type 7, myotonic dystrophy type 1, Huntington's disease and frontotemporal dementia/amyotrophic lateral sclerosis associated genes have been implicated in transcriptional regulation of sense gene expression, acting either at a transcriptional or posttranscriptional level. The recent evidence that antisense repeat RNAs could modulate gene expression broadens our understanding of the pathogenic pathways and adds more complexity to the development of therapeutic strategies for these disorders. In this review, we cover the amazing progress made in the understanding of the pathogenic mechanisms associated with repeat expansion neurodegenerative and neuromuscular diseases with a focus on the impact of antisense repeat transcription in the development of efficient therapies.
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11
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Khristich AN, Mirkin SM. On the wrong DNA track: Molecular mechanisms of repeat-mediated genome instability. J Biol Chem 2020; 295:4134-4170. [PMID: 32060097 PMCID: PMC7105313 DOI: 10.1074/jbc.rev119.007678] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Expansions of simple tandem repeats are responsible for almost 50 human diseases, the majority of which are severe, degenerative, and not currently treatable or preventable. In this review, we first describe the molecular mechanisms of repeat-induced toxicity, which is the connecting link between repeat expansions and pathology. We then survey alternative DNA structures that are formed by expandable repeats and review the evidence that formation of these structures is at the core of repeat instability. Next, we describe the consequences of the presence of long structure-forming repeats at the molecular level: somatic and intergenerational instability, fragility, and repeat-induced mutagenesis. We discuss the reasons for gender bias in intergenerational repeat instability and the tissue specificity of somatic repeat instability. We also review the known pathways in which DNA replication, transcription, DNA repair, and chromatin state interact and thereby promote repeat instability. We then discuss possible reasons for the persistence of disease-causing DNA repeats in the genome. We describe evidence suggesting that these repeats are a payoff for the advantages of having abundant simple-sequence repeats for eukaryotic genome function and evolvability. Finally, we discuss two unresolved fundamental questions: (i) why does repeat behavior differ between model systems and human pedigrees, and (ii) can we use current knowledge on repeat instability mechanisms to cure repeat expansion diseases?
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Affiliation(s)
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, Massachusetts 02155.
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12
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Rossi M, Farcy N, Starkstein SE, Merello M. Nosology and Phenomenology of Psychosis in Movement Disorders. Mov Disord Clin Pract 2020; 7:140-153. [PMID: 32071931 DOI: 10.1002/mdc3.12882] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/02/2019] [Accepted: 12/01/2019] [Indexed: 12/13/2022] Open
Abstract
Background Psychotic symptoms, such as delusions and hallucinations, are part of the clinical picture of several conditions presenting movement disorders. Phenomenology and epidemiology of psychosis in Parkinson's disease have received wide attention; however, the presence of psychosis in other movement disorders is, comparatively, less well known. Objectives To review psychotic symptoms present in different movement disorders. Methods A comprehensive and structured literature search was performed to identify and analyze data on patients with movement disorders and comorbid psychosis. Results In monogenic parkinsonisms, such as PARK-GBA, PARK-LRRK2, and PARK-SNCA, visual hallucinations related to dopamine replacement therapy are frequent as well as are delusions in PARK-LRRK2 and PARK-SNCA, but not in PARK-GBA. Different types of delusions and hallucinations are found in Huntington's disease and other choreic disorders. In Tourette's syndrome, paranoid delusions as well as visual, olfactory, and auditory hallucinations have been described, which usually develop after an average of 10 years of disease. Delusions in ataxias are more frequent in ATX-TBP, ATX-ATN1, and ATX-ATXN3, whereas it is rare in Friedreich's ataxia. Psychosis is also a prominent and frequent clinical feature in Fahr's disease, Wilson's disease, neurodegeneration with brain iron accumulation, and some lysosomal storage disorders, whereas it is uncommon in atypical parkinsonisms and dystonia. Psychosis usually occurs at late disease stages, but may appear as onset symptoms of the disease, especially in Wilson's disease, Huntington's disease, late-onset Tays-Sachs, and Niemann-Pick. Conclusion Psychosis is a frequent comorbidity in most hyper- and hypokinetic movement disorders. Appropriate recognition is relevant both in the early and late disease stages.
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Affiliation(s)
- Malco Rossi
- Movement Disorders Section, Neuroscience Department Raul Carrea Institute for Neurological Research (FLENI) Buenos Aires Argentina.,Pontificia Universidad Catolica Argentina (UCA) Buenos Aires Argentina
| | - Nicole Farcy
- Movement Disorders Section, Neuroscience Department Raul Carrea Institute for Neurological Research (FLENI) Buenos Aires Argentina
| | - Sergio E Starkstein
- School of Psychiatry and Clinical Neurosciences University of Western Australia Crawley WA Australia
| | - Marcelo Merello
- Movement Disorders Section, Neuroscience Department Raul Carrea Institute for Neurological Research (FLENI) Buenos Aires Argentina.,Pontificia Universidad Catolica Argentina (UCA) Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina
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13
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Nguyen L, Montrasio F, Pattamatta A, Tusi SK, Bardhi O, Meyer KD, Hayes L, Nakamura K, Banez-Coronel M, Coyne A, Guo S, Laboissonniere LA, Gu Y, Narayanan S, Smith B, Nitsch RM, Kankel MW, Rushe M, Rothstein J, Zu T, Grimm J, Ranum LPW. Antibody Therapy Targeting RAN Proteins Rescues C9 ALS/FTD Phenotypes in C9orf72 Mouse Model. Neuron 2019; 105:645-662.e11. [PMID: 31831332 DOI: 10.1016/j.neuron.2019.11.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/10/2019] [Accepted: 11/05/2019] [Indexed: 10/25/2022]
Abstract
The intronic C9orf72 G4C2 expansion, the most common genetic cause of ALS and FTD, produces sense- and antisense-expansion RNAs and six dipeptide repeat-associated, non-ATG (RAN) proteins, but their roles in disease are unclear. We generated high-affinity human antibodies targeting GA or GP RAN proteins. These antibodies cross the blood-brain barrier and co-localize with intracellular RAN aggregates in C9-ALS/FTD BAC mice. In cells, α-GA1 interacts with TRIM21, and α-GA1 treatment reduced GA levels, increased GA turnover, and decreased RAN toxicity and co-aggregation of proteasome and autophagy proteins to GA aggregates. In C9-BAC mice, α-GA1 reduced GA as well as GP and GR proteins, improved behavioral deficits, decreased neuroinflammation and neurodegeneration, and increased survival. Glycosylation of the Fc region of α-GA1 is important for cell entry and efficacy. These data demonstrate that RAN proteins drive C9-ALS/FTD in C9-BAC transgenic mice and establish a novel therapeutic approach for C9orf72 ALS/FTD and other RAN-protein diseases.
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Affiliation(s)
- Lien Nguyen
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | | | - Amrutha Pattamatta
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Solaleh Khoramian Tusi
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Olgert Bardhi
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Kevin D Meyer
- Neurimmune AG, 8952 Schlieren, Switzerland; Institute for Regenerative Medicine-IREM, University of Zurich, 8952 Schlieren, Switzerland
| | - Lindsey Hayes
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Katsuya Nakamura
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Monica Banez-Coronel
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Alyssa Coyne
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Shu Guo
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Lauren A Laboissonniere
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Yuanzheng Gu
- Neuromuscular and Movement Disorders, Biogen, Cambridge, MA 02142, USA
| | | | - Benjamin Smith
- Neuromuscular and Movement Disorders, Biogen, Cambridge, MA 02142, USA
| | - Roger M Nitsch
- Neurimmune AG, 8952 Schlieren, Switzerland; Institute for Regenerative Medicine-IREM, University of Zurich, 8952 Schlieren, Switzerland
| | - Mark W Kankel
- Neuromuscular and Movement Disorders, Biogen, Cambridge, MA 02142, USA
| | - Mia Rushe
- Neuromuscular and Movement Disorders, Biogen, Cambridge, MA 02142, USA
| | - Jeffrey Rothstein
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Tao Zu
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Jan Grimm
- Neurimmune AG, 8952 Schlieren, Switzerland
| | - Laura P W Ranum
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA.
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14
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Lalonde R, Strazielle C. Motor Performances of Spontaneous and Genetically Modified Mutants with Cerebellar Atrophy. THE CEREBELLUM 2019; 18:615-634. [PMID: 30820866 DOI: 10.1007/s12311-019-01017-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chance discovery of spontaneous mutants with atrophy of the cerebellar cortex has unearthed genes involved in optimizing motor coordination. Rotorod, stationary beam, and suspended wire tests are useful in delineating behavioral phenotypes of spontaneous mutants with cerebellar atrophy such as Grid2Lc, Grid2ho, Rorasg, Agtpbp1pcd, Relnrl, and Dab1scm. Likewise, transgenic or null mutants serving as experimental models of spinocerebellar ataxia (SCA) are phenotyped with the same tests. Among experimental models of autosomal dominant SCA, rotorod deficits were reported in SCA1 to 3, SCA5 to 8, SCA14, SCA17, and SCA27 and stationary beam deficits in SCA1 to 3, SCA5, SCA6, SCA13, SCA17, and SCA27. Beam tests are sensitive to experimental therapies of various kinds including molecules affecting glutamate signaling, mesenchymal stem cells, anti-oligomer antibodies, lentiviral vectors carrying genes, interfering RNAs, or neurotrophic factors, and interbreeding with other mutants.
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Affiliation(s)
- Robert Lalonde
- Department of Psychology, University of Rouen, 76821, Mont-Saint-Aignan Cedex, France.
| | - Catherine Strazielle
- Laboratory of Stress, Immunity, and Pathogens EA7300, and CHRU of Nancy, University of Lorraine, 54500, Vandoeuvre-les-Nancy, France
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15
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Genetic and clinical analyses of spinocerebellar ataxia type 8 in mainland China. J Neurol 2019; 266:2979-2986. [DOI: 10.1007/s00415-019-09519-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/19/2019] [Accepted: 08/19/2019] [Indexed: 02/01/2023]
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16
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Corral-Juan M, Serrano-Munuera C, Rábano A, Cota-González D, Segarra-Roca A, Ispierto L, Cano-Orgaz AT, Adarmes AD, Méndez-Del-Barrio C, Jesús S, Mir P, Volpini V, Alvarez-Ramo R, Sánchez I, Matilla-Dueñas A. Clinical, genetic and neuropathological characterization of spinocerebellar ataxia type 37. Brain 2019; 141:1981-1997. [PMID: 29939198 DOI: 10.1093/brain/awy137] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/03/2018] [Indexed: 12/20/2022] Open
Abstract
The autosomal dominant spinocerebellar ataxias (SCAs) consist of a highly heterogeneous group of rare movement disorders characterized by progressive cerebellar ataxia variably associated with ophthalmoplegia, pyramidal and extrapyramidal signs, dementia, pigmentary retinopathy, seizures, lower motor neuron signs, or peripheral neuropathy. Over 41 different SCA subtypes have been described evidencing the high clinical and genetic heterogeneity. We previously reported a novel spinocerebellar ataxia type subtype, SCA37, linked to an 11-Mb genomic region on 1p32, in a large Spanish ataxia pedigree characterized by ataxia and a pure cerebellar syndrome distinctively presenting with early-altered vertical eye movements. Here we demonstrate the segregation of an unstable intronic ATTTC pentanucleotide repeat mutation within the 1p32 5' non-coding regulatory region of the gene encoding the reelin adaptor protein DAB1, implicated in neuronal migration, as the causative genetic defect of the disease in four Spanish SCA37 families. We describe the clinical-genetic correlation and the first SCA37 neuropathological findings caused by dysregulation of cerebellar DAB1 expression. Post-mortem neuropathology of two patients with SCA37 revealed severe loss of Purkinje cells with abundant astrogliosis, empty baskets, occasional axonal spheroids, and hypertrophic fibres by phosphorylated neurofilament immunostaining in the cerebellar cortex. The remaining cerebellar Purkinje neurons showed loss of calbindin immunoreactivity, aberrant dendrite arborization, nuclear pathology including lobulation, irregularity, and hyperchromatism, and multiple ubiquitinated perisomatic granules immunostained for DAB1. A subpopulation of Purkinje cells was found ectopically mispositioned within the cerebellar cortex. No significant neuropathological alterations were identified in other brain regions in agreement with a pure cerebellar syndrome. Importantly, we found that the ATTTC repeat mutation dysregulated DAB1 expression and induced an RNA switch resulting in the upregulation of reelin-DAB1 and PI3K/AKT signalling in the SCA37 cerebellum. This study reveals the unstable ATTTC repeat mutation within the DAB1 gene as the underlying genetic cause and provides evidence of reelin-DAB1 signalling dysregulation in the spinocerebellar ataxia type 37.
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Affiliation(s)
- Marc Corral-Juan
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Health Sciences Research Institute Germans Trias i Pujol (IGTP)-Universitat Autònoma de Barcelona, Can Ruti Campus, Badalona, Barcelona, Spain
| | | | | | - Daniel Cota-González
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Health Sciences Research Institute Germans Trias i Pujol (IGTP)-Universitat Autònoma de Barcelona, Can Ruti Campus, Badalona, Barcelona, Spain
| | - Anna Segarra-Roca
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Health Sciences Research Institute Germans Trias i Pujol (IGTP)-Universitat Autònoma de Barcelona, Can Ruti Campus, Badalona, Barcelona, Spain
| | - Lourdes Ispierto
- Neurodegeneration Unit, Neurology Service, Department of Neuroscience, University Hospital Germans Trias i Pujol (HUGTiP), Can Ruti Campus, Badalona, Barcelona, Spain
| | | | - Astrid D Adarmes
- Unidad de Trastornos del Movimiento, Servicio de Neurología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain
| | - Carlota Méndez-Del-Barrio
- Unidad de Trastornos del Movimiento, Servicio de Neurología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain
| | - Silvia Jesús
- Unidad de Trastornos del Movimiento, Servicio de Neurología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain
| | - Pablo Mir
- Unidad de Trastornos del Movimiento, Servicio de Neurología, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain.,CIBERNED, Spain
| | | | - Ramiro Alvarez-Ramo
- Neurodegeneration Unit, Neurology Service, Department of Neuroscience, University Hospital Germans Trias i Pujol (HUGTiP), Can Ruti Campus, Badalona, Barcelona, Spain
| | - Ivelisse Sánchez
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Health Sciences Research Institute Germans Trias i Pujol (IGTP)-Universitat Autònoma de Barcelona, Can Ruti Campus, Badalona, Barcelona, Spain
| | - Antoni Matilla-Dueñas
- Functional and Translational Neurogenetics Unit, Department of Neuroscience, Health Sciences Research Institute Germans Trias i Pujol (IGTP)-Universitat Autònoma de Barcelona, Can Ruti Campus, Badalona, Barcelona, Spain
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17
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Banez-Coronel M, Ranum LPW. Repeat-associated non-AUG (RAN) translation: insights from pathology. J Transl Med 2019; 99:929-942. [PMID: 30918326 PMCID: PMC7219275 DOI: 10.1038/s41374-019-0241-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
More than 40 different neurological diseases are caused by microsatellite repeat expansions. Since the discovery of repeat-associated non-AUG (RAN) translation by Zu et al. in 2011, nine expansion disorders have been identified as RAN-positive diseases. RAN proteins are translated from different types of nucleotide repeat expansions and can be produced from both sense and antisense transcripts. In some diseases, RAN proteins have been shown to accumulate in affected brain regions. Here we review the pathological and molecular aspects associated with RAN protein accumulation for each particular disorder, the correlation between disease pathology and the available in vivo models and the common aspects shared by some of the newly discovered RAN proteins.
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Affiliation(s)
- Monica Banez-Coronel
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA.
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
- Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.
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18
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Abstract
Spinocerebellar ataxia type 8 (SCA8) is a rare autosomal dominant neurodegenerative disease caused by expanded CTA/CTG repeats in the ATXN8OS gene. Many patients had pure cerebellar ataxia, while some had parkinsonism, both without causal explanation. We analyzed the ATXN8OS gene in 150 Japanese patients with ataxia and 76 patients with Parkinson's disease or related disorders. We systematically reassessed 123 patients with SCA8, both our patients and those reported in other studies. Two patients with progressive supranuclear palsy (PSP) had mutations in the ATXN8OS gene. Systematic analyses revealed that patients with parkinsonism had significantly shorter CTA/CTG repeat expansions and older age at onset than those with predominant ataxia. We show the imaging results of patients with and without parkinsonism. We also found a significant inverse relationship between repeat sizes and age at onset in all patients, which has not been detected previously. Our results may be useful to genetic counseling, improve understanding of the pathomechanism, and extend the clinical phenotype of SCA8.
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19
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Abstract
Microsatellite expansions cause more than 40 neurological disorders, including Huntington's disease, myotonic dystrophy, and C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). These repeat expansion mutations can produce repeat-associated non-ATG (RAN) proteins in all three reading frames, which accumulate in disease-relevant tissues. There has been considerable interest in RAN protein products and their downstream consequences, particularly for the dipeptide proteins found in C9ORF72 ALS/FTD. Understanding how RAN translation occurs, what cellular factors contribute to RAN protein accumulation, and how these proteins contribute to disease should lead to a better understanding of the basic mechanisms of gene expression and human disease.
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Affiliation(s)
- John Douglas Cleary
- From the Center for NeuroGenetics
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
| | - Amrutha Pattamatta
- From the Center for NeuroGenetics
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
| | - Laura P W Ranum
- From the Center for NeuroGenetics,
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
- Neurology, College of Medicine
- McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
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20
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Ayhan F, Perez BA, Shorrock HK, Zu T, Banez-Coronel M, Reid T, Furuya H, Clark HB, Troncoso JC, Ross CA, Subramony SH, Ashizawa T, Wang ET, Yachnis AT, Ranum LP. SCA8 RAN polySer protein preferentially accumulates in white matter regions and is regulated by eIF3F. EMBO J 2018; 37:embj.201899023. [PMID: 30206144 DOI: 10.15252/embj.201899023] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8) is caused by a bidirectionally transcribed CTG·CAG expansion that results in the in vivo accumulation of CUG RNA foci, an ATG-initiated polyGln and a polyAla protein expressed by repeat-associated non-ATG (RAN) translation. Although RAN proteins have been reported in a growing number of diseases, the mechanisms and role of RAN translation in disease are poorly understood. We report a novel toxic SCA8 polySer protein which accumulates in white matter (WM) regions as aggregates that increase with age and disease severity. WM regions with polySer aggregates show demyelination and axonal degeneration in SCA8 human and mouse brains. Additionally, knockdown of the eukaryotic translation initiation factor eIF3F in cells reduces steady-state levels of SCA8 polySer and other RAN proteins. Taken together, these data show polySer and WM abnormalities contribute to SCA8 and identify eIF3F as a novel modulator of RAN protein accumulation.
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Affiliation(s)
- Fatma Ayhan
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Barbara A Perez
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hannah K Shorrock
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tao Zu
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Monica Banez-Coronel
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tammy Reid
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hirokazu Furuya
- Department of Neurology, Kochi Medical School, Kochi University, Kochi, Japan.,Department of Neurology, Neuro-Muscular Center, NHO Omuta Hospital, Fukuoka, Japan
| | - H Brent Clark
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Juan C Troncoso
- Department of Pathology and Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christopher A Ross
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pharmacology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Huntington's Disease Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - S H Subramony
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tetsuo Ashizawa
- Department of Neurology, Houston Methodist Hospital, Houston, TX, USA
| | - Eric T Wang
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Anthony T Yachnis
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Laura Pw Ranum
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA .,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.,Genetics Institute, University of Florida, Gainesville, FL, USA
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21
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Hirano M, Samukawa M, Isono C, Saigoh K, Nakamura Y, Kusunoki S. Noncoding repeat expansions for ALS in Japan are associated with the ATXN8OS gene. NEUROLOGY-GENETICS 2018; 4:e252. [PMID: 30109267 PMCID: PMC6089696 DOI: 10.1212/nxg.0000000000000252] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022]
Abstract
Objective To assess the contribution of noncoding repeat expansions in Japanese patients with amyotrophic lateral sclerosis (ALS). Methods Sporadic ALS in Western countries is frequently associated with noncoding repeat expansions in the C9ORF72 gene. Spinocerebellar ataxia type 8 (SCA8) is another noncoding repeat disease caused by expanded CTA/CTG repeats in the ATXN8OS gene. Although the involvement of upper and lower motor neurons in SCA8 has been reported, a positive association between SCA8 and ALS remains unestablished. Spinocerebellar ataxia type 36 is a recently identified disease caused by noncoding repeat expansions in the NOP56 gene and is characterized by motor neuron involvement. We collected blood samples from 102 Japanese patients with sporadic ALS and analyzed the ATXN8OS gene by the PCR–Sanger sequencing method and the C9ORF72 and NOP56 genes by repeat-primed PCR assay. Results Three patients with ALS (3%) had mutations in the ATXN8OS gene, whereas no patient had a mutation in the C9ORF72 or NOP56 gene. The mutation-positive patients were clinically characterized by neck weakness or bulbar-predominant symptoms. None of our patients had apparent cerebellar atrophy on MRI, but 2 had nonsymptomatic abnormalities in the white matter or putamen. Conclusions Our finding reveals the importance of noncoding repeat expansions in Japanese patients with ALS and extends the clinical phenotype of SCA8. Three percent seems small but is still relatively large for Japan, considering that the most commonly mutated genes, including the SOD1 and SQSTM1 genes, only account for 2%–3% of sporadic patients each.
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Affiliation(s)
- Makito Hirano
- Department of Neurology (M.H., M.S., K.S., and S.K.), Kindai University Faculty of Medicine, Osakasayama, Japan; and Department of Neurology (M.H., C.I., and Y.N.), Kindai University Sakai Hospital, Japan
| | - Makoto Samukawa
- Department of Neurology (M.H., M.S., K.S., and S.K.), Kindai University Faculty of Medicine, Osakasayama, Japan; and Department of Neurology (M.H., C.I., and Y.N.), Kindai University Sakai Hospital, Japan
| | - Chiharu Isono
- Department of Neurology (M.H., M.S., K.S., and S.K.), Kindai University Faculty of Medicine, Osakasayama, Japan; and Department of Neurology (M.H., C.I., and Y.N.), Kindai University Sakai Hospital, Japan
| | - Kazumasa Saigoh
- Department of Neurology (M.H., M.S., K.S., and S.K.), Kindai University Faculty of Medicine, Osakasayama, Japan; and Department of Neurology (M.H., C.I., and Y.N.), Kindai University Sakai Hospital, Japan
| | - Yusaku Nakamura
- Department of Neurology (M.H., M.S., K.S., and S.K.), Kindai University Faculty of Medicine, Osakasayama, Japan; and Department of Neurology (M.H., C.I., and Y.N.), Kindai University Sakai Hospital, Japan
| | - Susumu Kusunoki
- Department of Neurology (M.H., M.S., K.S., and S.K.), Kindai University Faculty of Medicine, Osakasayama, Japan; and Department of Neurology (M.H., C.I., and Y.N.), Kindai University Sakai Hospital, Japan
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Abstract
More than 40 diseases, most of which primarily affect the nervous system, are caused by expansions of simple sequence repeats dispersed throughout the human genome. Expanded trinucleotide repeat diseases were discovered first and remain the most frequent. More recently tetra-, penta-, hexa-, and even dodeca-nucleotide repeat expansions have been identified as the cause of human disease, including some of the most common genetic disorders seen by neurologists. Repeat expansion diseases include both causes of myotonic dystrophy (DM1 and DM2), the most common genetic cause of amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72), Huntington disease, and eight other polyglutamine disorders, including the most common forms of dominantly inherited ataxia, the most common recessive ataxia (Friedreich ataxia), and the most common heritable mental retardation (fragile X syndrome). Here I review distinctive features of this group of diseases that stem from the unusual, dynamic nature of the underlying mutations. These features include marked clinical heterogeneity and the phenomenon of clinical anticipation. I then discuss the diverse molecular mechanisms driving disease pathogenesis, which vary depending on the repeat sequence, size, and location within the disease gene, and whether the repeat is translated into protein. I conclude with a brief clinical and genetic description of individual repeat expansion diseases that are most relevant to neurologists.
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Abstract
Trinucleotide repeat disorders comprise a variable group of inherited neurodegenerative diseases, with a large range in prevalence figures. There is a broad range in clinical presentations, but many of these diseases lead to some form of ataxia or other movement disorders, which are frequently combined with cognitive or psychiatric disturbances. This group can be divided into CAG- versus non-CAG-repeat diseases. Apart from spinocerebellar ataxia type 6 and 12 (SCA6 and SCA12), these CAG-repeat diseases, as well as Huntington disease-like 2 (HDL2) and SCA8, can be neuropathologically identified using 1C2 polyglutamine antibodies. In fragile X-associated tremor and ataxia, SCA6 and SCA12 ubiquitin/p62-positive and 1C2-negative inclusion bodies can be observed. In the other diseases proteinaceous inclusions are not found. For definite diagnosis genetic analysis is necessary.
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Affiliation(s)
- W F A Den Dunnen
- Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands.
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Cintra VP, Lourenço CM, Rocha MMV, Tomaselli PJ, Marques W. Analysis of a fully penetrant spinocerebellar ataxia type 8 Brazilian family. Acta Neurol Scand 2017; 136:541-545. [PMID: 28229454 DOI: 10.1111/ane.12744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2017] [Indexed: 01/03/2023]
Abstract
Spinocerebellar ataxia type 8 (SCA8) is a progressive neurological disorder caused by the expanded repeat CTA/CTG of two overlapping genes, ATXN8OS and ATXN8, expressed bidirectionally. Normal alleles have 15-50 repeats, and pathogenic alleles range from 71 to 1300 repeats. The disorder is relatively rare, accounting for about 2%-5% of the autosomal dominant forms of hereditary ataxia worldwide. However, the prevalence of disease-causing ATXN8OS/ATXN8 expansions is higher than the disease because of the reduced penetrance of the expanded allele. The aim of this study was to describe the first fully penetrant SCA8 family showing mixed Brazilian African and Amerindian origin. Eight members of this family were evaluated-the mother and seven offspring-through a complete neurological examination conducted at the Neurogenetics Clinic, HCFMRP-USP in Brazil. The number of CTA/CTG repeats was obtained after polymerase chain reaction (PCR) and fragment analysis. The haplotype analysis was conducted using a microsatellite marker, D13S1296, and four single nucleotide polymorphisms (SNPs), rs1831189, rs8002227, rs11841483, and rs72284461, all spanning a 70.1 Mb region on chromosome 13q21.3. The molecular analysis showed that the expansions ranged from 104 to 109 CTA/CTG repeats in the six affected individuals and were absent in two asymptomatic daughters (aged 53 and 40 years). Three SNPs cosegregate with the expanded alleles, confirming the connection between expansion and disease in this family. As the SCA8 diagnosis demands careful interpretation, we suggest the use of linkage analysis to observe segregation of the mutation, making more accurate its genotyping.
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Affiliation(s)
- V. P. Cintra
- Department of Neurosciences and Behavior Sciences; Ribeirão Preto School of Medicine; University of São Paulo (HCFMRP-USP); Ribeirão Preto SP Brazil
| | - C. M. Lourenço
- Department of Neurosciences and Behavior Sciences; Ribeirão Preto School of Medicine; University of São Paulo (HCFMRP-USP); Ribeirão Preto SP Brazil
| | - M. M. V. Rocha
- Department of Neurosciences and Behavior Sciences; Ribeirão Preto School of Medicine; University of São Paulo (HCFMRP-USP); Ribeirão Preto SP Brazil
| | - P. J. Tomaselli
- Department of Neurosciences and Behavior Sciences; Ribeirão Preto School of Medicine; University of São Paulo (HCFMRP-USP); Ribeirão Preto SP Brazil
| | - W. Marques
- Department of Neurosciences and Behavior Sciences; Ribeirão Preto School of Medicine; University of São Paulo (HCFMRP-USP); Ribeirão Preto SP Brazil
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Morriss GR, Cooper TA. Protein sequestration as a normal function of long noncoding RNAs and a pathogenic mechanism of RNAs containing nucleotide repeat expansions. Hum Genet 2017; 136:1247-1263. [PMID: 28484853 DOI: 10.1007/s00439-017-1807-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/28/2017] [Indexed: 12/12/2022]
Abstract
An emerging class of long noncoding RNAs (lncRNAs) function as decoy molecules that bind and sequester proteins thereby inhibiting their normal functions. Titration of proteins by lncRNAs has wide-ranging effects affecting nearly all steps in gene expression. While decoy lncRNAs play a role in normal physiology, RNAs expressed from alleles containing nucleotide repeat expansions can be pathogenic due to protein sequestration resulting in disruption of normal functions. This review focuses on commonalities between decoy lncRNAs that regulate gene expression by competitive inhibition of protein function through sequestration and specific examples of nucleotide repeat expansion disorders mediated by toxic RNA that sequesters RNA-binding proteins and impedes their normal functions. Understanding how noncoding RNAs compete with various RNA and DNA molecules for binding of regulatory proteins will provide insight into how similar mechanisms contribute to disease pathogenesis.
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Affiliation(s)
- Ginny R Morriss
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Thomas A Cooper
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.
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Mandrile G, Di Gregorio E, Goel H, Giachino D, De Mercanti S, Iudicello M, Rolando M, Losa S, De Marchi M, Brusco A. Heterozygous Deletion of KLHL1/ATX8OS at the SCA8 Locus Is Unlikely Associated With Cerebellar Impairment in Humans. THE CEREBELLUM 2016; 15:208-12. [PMID: 25998497 DOI: 10.1007/s12311-015-0679-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Giorgia Mandrile
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
| | - Eleonora Di Gregorio
- Department of Medical Sciences, University of Torino, via Santena 19, Torino, 10126, Italy
- Medical Genetics, Città della Salute e della Scienza di Torino University Hospital, Torino, 10126, Italy
| | - Himanshu Goel
- Faculty of Health and Medicine, Callaghan and Hunter Genetics, University of Newcastle, Waratah, NSW2308, Australia
| | - Daniela Giachino
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
| | - Stefania De Mercanti
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
- Neurology Division, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
| | - Marco Iudicello
- Neurology Division, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
| | - Marco Rolando
- Azienda Sanitaria Locale TO3 di Collegno e Pinerolo, Neuropsichiatria Infantile, Collegno, 10093, Italy
| | - Sabrina Losa
- Azienda Sanitaria Locale TO3 di Collegno e Pinerolo, Neuropsichiatria Infantile, Collegno, 10093, Italy
| | - Mario De Marchi
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, via Santena 19, Torino, 10126, Italy.
- Medical Genetics, Città della Salute e della Scienza di Torino University Hospital, Torino, 10126, Italy.
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Shukla S, Parker R. Hypo- and Hyper-Assembly Diseases of RNA-Protein Complexes. Trends Mol Med 2016; 22:615-628. [PMID: 27263464 DOI: 10.1016/j.molmed.2016.05.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 12/14/2022]
Abstract
A key aspect of cellular function is the proper assembly and utilization of ribonucleoproteins (RNPs). Recent studies have shown that hyper- or hypo-assembly of various RNPs can lead to human diseases. Defects in the formation of RNPs lead to 'RNP hypo-assembly diseases', which can be caused by RNA degradation outcompeting RNP assembly. By contrast, excess RNP assembly, either in higher order RNP granules, or due to the expression of repeat-containing RNAs, can lead to 'RNP hyper-assembly diseases'. Here, we discuss the most recent advances in understanding the cause of disease onset, as well as potential therapies from the aspect of modulating RNP assembly in the cell, which presents a novel route to the treatment of these diseases.
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Affiliation(s)
- Siddharth Shukla
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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Termsarasab P, Thammongkolchai T, Rucker JC, Frucht SJ. The diagnostic value of saccades in movement disorder patients: a practical guide and review. JOURNAL OF CLINICAL MOVEMENT DISORDERS 2015; 2:14. [PMID: 26788350 PMCID: PMC4710978 DOI: 10.1186/s40734-015-0025-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/01/2015] [Indexed: 12/11/2022]
Abstract
Saccades are rapid eye movements designed to shift the fovea to objects of visual interest. Abnormalities of saccades offer important clues in the diagnosis of a number of movement disorders. In this review, we explore the anatomy of horizontal and vertical saccades, discuss practical aspects of their examination, and review how saccadic abnormalities in hyperkinetic and hypokinetic movement disorders aid in diagnosis, with video demonstration of classic examples. Documentation of the ease of saccade initiation, range of motion and conjugacy of saccades, speed and accuracy of saccades, dynamic saccadic trajectory, and the presence or absence of saccadic intrusions and oscillations are important components of this exam. We also provide a practical algorithm to demonstrate the value of saccades in the differential diagnosis of the movement disorders patient.
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Affiliation(s)
- Pichet Termsarasab
- Movement Disorder Division, Department of Neurology, Icahn School of Medicine at Mount Sinai, 5 East 98th St, New York, 10029 USA
| | | | - Janet C Rucker
- Division of Neuro-ophthalmology, Department of Neurology, New York University School of Medicine, New York, USA
| | - Steven J Frucht
- Movement Disorder Division, Department of Neurology, Icahn School of Medicine at Mount Sinai, 5 East 98th St, New York, 10029 USA
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Hekman KE, Gomez CM. The autosomal dominant spinocerebellar ataxias: emerging mechanistic themes suggest pervasive Purkinje cell vulnerability. J Neurol Neurosurg Psychiatry 2015; 86:554-61. [PMID: 25136055 PMCID: PMC6718294 DOI: 10.1136/jnnp-2014-308421] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/27/2014] [Indexed: 01/05/2023]
Abstract
The spinocerebellar ataxias are a genetically heterogeneous group of disorders with clinically overlapping phenotypes arising from Purkinje cell degeneration, cerebellar atrophy and varying degrees of degeneration of other grey matter regions. For 22 of the 32 subtypes, a genetic cause has been identified. While recurring themes are emerging, there is no clear correlation between the clinical phenotype or penetrance, the type of genetic defect or the category of the disease mechanism, or the neuronal types involved beyond Purkinje cells. These phenomena suggest that cerebellar Purkinje cells may be a uniquely vulnerable neuronal cell type, more susceptible to a wider variety of genetic/cellular insults than most other neuron types.
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Affiliation(s)
- Katherine E Hekman
- Department of Vascular Surgery, McGaw Medical Center of Northwestern University, Chicago, Illinois, USA
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Parkinsonism in spinocerebellar ataxia. BIOMED RESEARCH INTERNATIONAL 2015; 2015:125273. [PMID: 25866756 PMCID: PMC4383270 DOI: 10.1155/2015/125273] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/29/2014] [Accepted: 10/13/2014] [Indexed: 11/17/2022]
Abstract
Spinocerebellar ataxia (SCA) presents heterogeneous clinical phenotypes, and parkinsonism is reported in diverse SCA subtypes. Both levodopa responsive Parkinson disease (PD) like phenotype and atypical parkinsonism have been described especially in SCA2, SCA3, and SCA17 with geographic differences in prevalence. SCA2 is the most frequently reported subtype of SCA related to parkinsonism worldwide. Parkinsonism in SCA2 has unique genetic characteristics, such as low number of expansions and interrupted structures, which may explain the sporadic cases with low penetrance. Parkinsonism in SCA17 is more remarkable in Asian populations especially in Korea. In addition, an unclear cutoff of the pathologic range is the key issue in SCA17 related parkinsonism. SCA3 is more common in western cohorts. SCA6 and SCA8 have also been reported with a PD-like phenotype. Herein, we reviewed the epidemiologic, clinical, genetic, and pathologic features of parkinsonism in SCAs.
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deLorimier E, Coonrod LA, Copperman J, Taber A, Reister EE, Sharma K, Todd PK, Guenza MG, Berglund JA. Modifications to toxic CUG RNAs induce structural stability, rescue mis-splicing in a myotonic dystrophy cell model and reduce toxicity in a myotonic dystrophy zebrafish model. Nucleic Acids Res 2014; 42:12768-78. [PMID: 25303993 PMCID: PMC4227782 DOI: 10.1093/nar/gku941] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
CUG repeat expansions in the 3′ UTR of dystrophia myotonica protein kinase (DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2′-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2′-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecular dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.
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Affiliation(s)
- Elaine deLorimier
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Leslie A Coonrod
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Jeremy Copperman
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Alex Taber
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Emily E Reister
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Kush Sharma
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Marina G Guenza
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - J Andrew Berglund
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
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Duan R, Sharma S, Xia Q, Garber K, Jin P. Towards Understanding RNA-Mediated Neurological Disorders. J Genet Genomics 2014; 41:473-84. [DOI: 10.1016/j.jgg.2014.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 08/10/2014] [Accepted: 08/12/2014] [Indexed: 12/14/2022]
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Bhan A, Mandal SS. Long noncoding RNAs: emerging stars in gene regulation, epigenetics and human disease. ChemMedChem 2014; 9:1932-56. [PMID: 24677606 DOI: 10.1002/cmdc.201300534] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 12/19/2022]
Abstract
Noncoding RNAs (ncRNAs) are classes of transcripts that are encoded by the genome and transcribed but never get translated into proteins. Though not translated into proteins, ncRNAs play pivotal roles in a variety of cellular functions. Here, we review the functions of long noncoding RNAs (lncRNAs) and their implications in various human diseases. Increasing numbers of studies demonstrate that lncRNAs play critical roles in regulation of protein-coding genes, maintenance of genomic integrity, dosage compensation, genomic imprinting, mRNA processing, cell differentiation, and development. Misregulation of lncRNAs is associated with a variety of human diseases, including cancer, immune and neurological disorders. Different classes of lncRNAs, their functions, mechanisms of action, and associations with different human diseases are summarized in detail, highlighting their as yet untapped potential in therapy.
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Affiliation(s)
- Arunoday Bhan
- Epigenetics Research Laboratory, Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019 (USA)
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35
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Martí E, Estivill X. Small non-coding RNAs add complexity to the RNA pathogenic mechanisms in trinucleotide repeat expansion diseases. Front Mol Neurosci 2013; 6:45. [PMID: 24348326 PMCID: PMC3848198 DOI: 10.3389/fnmol.2013.00045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 11/12/2013] [Indexed: 12/02/2022] Open
Abstract
Trinucleotide-repeat expansion diseases (TREDs) are a group of inherited human genetic disorders normally involving late-onset neurological/neurodegenerative affectation. Trinucleotide-repeat expansions occur in coding and non-coding regions of unique genes that typically result in protein and RNA toxic gain of function, respectively. In polyglutamine (polyQ) disorders caused by an expanded CAG repeat in the coding region of specific genes, neuronal dysfunction has been traditionally linked to the long polyQ stretch. However, a number of evidences suggest a detrimental role of the expanded/mutant mRNA, which may contribute to cell function impairment. In this review we describe the mechanisms of RNA-induced toxicity in TREDs with special focus in small-non-coding RNA pathogenic mechanisms and we summarize and comment on translational approaches targeting the expanded trinucleotide-repeat for disease modifying therapies.
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Affiliation(s)
- Eulàlia Martí
- Genomics and Disease, Bioinformatics and Genomics Programme, Centre for Genomic Regulation Barcelona, Spain ; Universitat Pompeu Fabra Barcelona, Spain
| | - Xavier Estivill
- Genomics and Disease, Bioinformatics and Genomics Programme, Centre for Genomic Regulation Barcelona, Spain ; Universitat Pompeu Fabra Barcelona, Spain
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Kim JS, Son TO, Youn J, Ki CS, Cho JW. Non-Ataxic Phenotypes of SCA8 Mimicking Amyotrophic Lateral Sclerosis and Parkinson Disease. J Clin Neurol 2013; 9:274-9. [PMID: 24285970 PMCID: PMC3840139 DOI: 10.3988/jcn.2013.9.4.274] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 03/06/2013] [Accepted: 03/06/2013] [Indexed: 12/13/2022] Open
Abstract
Background Spinocerebellar ataxia (SCA) type 8 (SCA8) is an inherited neurodegenerative disorder caused by the expansion of untranslated CTA/CTG triplet repeats on 13q21. The phenomenology of SCA8 is relatively varied when compared to the other types of SCAs and its spectrum is not well established. Case Report Two newly detected cases of SCA8 with the nonataxic phenotype and unusual clinical manifestations such as dopaminergic-treatment-responsive parkinsonism and amyotrophic lateral sclerosis (ALS) are described herein. Family A expressed good dopaminergic treatment-responsive parkinsonism as an initial manifestation and developed mild cerebellar ataxia with additional movements, including dystonic gait and unusual oscillatory movement of the trunk, during the disease course. The proband of family B presented as probable ALS with cerebellar atrophy on brain MRI, with a positive family history (a brother with typical cerebellar ataxia) and genetic confirmation for SCA8. Conclusions Our findings support that the non-ataxic phenotypes could be caused by a mutation of the SCA8 locus which might affect neurons other than the cerebellum.
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Affiliation(s)
- Ji Sun Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. ; Department of Neurology, Soonchunhyang University Hospital, Soonchunhyang University School of Medicine, Seoul, Korea
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Figley MD, Thomas A, Gitler AD. Evaluating noncoding nucleotide repeat expansions in amyotrophic lateral sclerosis. Neurobiol Aging 2013; 35:936.e1-4. [PMID: 24269018 DOI: 10.1016/j.neurobiolaging.2013.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/16/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Intermediate-length polyglutamine expansions in ataxin 2 are a risk factor for amyotrophic lateral sclerosis (ALS). The polyglutamine tract is encoded by a trinucleotide repeat in a coding region of the ataxin 2 gene (ATXN2). Noncoding nucleotide repeat expansions in several genes are also associated with neurodegenerative and neuromuscular diseases. For example, hexanucleotide repeat expansions located in a noncoding region of C9ORF72 are the most common cause of ALS. We sought to assess a potential larger role of noncoding nucleotide repeat expansions in ALS. We analyzed the nucleotide repeat lengths of 6 genes (ATXN8, ATXN10, PPP2R2B, NOP56, DMPK, and JPH3) that have previously been associated with neurologic or neuromuscular disorders, in several hundred sporadic patients with ALS and healthy control subjects. We report no association between ALS and repeat length in any of these genes, suggesting that variation in the noncoding repetitive regions in these genes does not contribute to ALS.
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Affiliation(s)
- Matthew D Figley
- Department of Genetics, Stanford University School of Medicine, Standford, CA, USA; Stanford Neuroscience Graduate Program, Stanford University School of Medicine, Stanford, CA, USA
| | - Anna Thomas
- Department of Genetics, Stanford University School of Medicine, Standford, CA, USA; Presentation High School, San Jose, CA, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Standford, CA, USA.
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Magnetic resonance imaging biomarkers in patients with progressive ataxia: current status and future direction. THE CEREBELLUM 2013; 12:245-66. [PMID: 22828959 DOI: 10.1007/s12311-012-0405-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
A diagnostic challenge commonly encountered in neurology is that of an adult patient presenting with ataxia. The differential is vast and clinical assessment alone may not be sufficient due to considerable overlap between different causes of ataxia. Magnetic resonance (MR)-based biomarkers such as voxel-based morphometry, MR spectroscopy, diffusion-weighted and diffusion-tensor imaging and functional MR imaging are gaining great attention for their potential as indicators of disease. A number of studies have reported correlation with clinical severity and underlying pathophysiology, and in some cases, MR imaging has been shown to allow differentiation of conditions causing ataxia. However, despite recent advances, their sensitivity and specificity vary. In addition, questions remain over their validity and reproducibility, especially when applied in routine clinical practice. This article extensively reviews the current literature regarding MR-based biomarkers for the patient with predominantly adult-onset ataxia. Imaging features characteristic of a particular ataxia are provided and features differentiating ataxia groups and subgroups are discussed. Finally, discussion will turn to the feasibility of applying these biomarkers in routine clinical practice.
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Koutsis G, Karadima G, Pandraud A, Sweeney MG, Paudel R, Houlden H, Wood NW, Panas M. Genetic screening of Greek patients with Huntington’s disease phenocopies identifies an SCA8 expansion. J Neurol 2013; 259:1874-8. [PMID: 22297462 DOI: 10.1007/s00415-012-6430-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 01/17/2012] [Accepted: 01/18/2012] [Indexed: 02/06/2023]
Abstract
Huntington’s disease (HD) is an autosomal dominant disorder characterized by a triad of chorea, psychiatric disturbance and cognitive decline. Around 1% of patients with HD-like symptoms lack the causative HD expansion and are considered HD phenocopies. Genetic diseases that can present as HD phenocopies include HD-like syndromes such as HDL1, HDL2 and HDL4 (SCA17), some spinocerebellar ataxias (SCAs) and dentatorubral-pallidoluysian atrophy (DRPLA). In this study we screened a cohort of 21 Greek patients with HD phenocopy syndromes formutations causing HDL2, SCA17, SCA1, SCA2, SCA3,SCA8, SCA12 and DRPLA. Fifteen patients (71%) had a positive family history. We identified one patient (4.8% of the total cohort) with an expansion of 81 combined CTA/CTG repeats at the SCA8 locus. This falls within what is believed to be the high-penetrance allele range. In addition to the classic HD triad, the patient had features of dystonia and oculomotor apraxia. There were no cases of HDL2, SCA17, SCA1, SCA2, SCA3, SCA12 or DRPLA. Given the controversy surrounding the SCA8 expansion, the present finding may be incidental. However, if pathogenic, it broadens the phenotype that may be associated with SCA8 expansions. The absence of any other mutations in our cohort is not surprising, given the low probability of reaching a genetic diagnosis in HD phenocopy patients.
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Affiliation(s)
- G Koutsis
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK.
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Belzil VV, Gendron TF, Petrucelli L. RNA-mediated toxicity in neurodegenerative disease. Mol Cell Neurosci 2012; 56:406-19. [PMID: 23280309 DOI: 10.1016/j.mcn.2012.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 12/19/2012] [Accepted: 12/21/2012] [Indexed: 12/12/2022] Open
Abstract
Cellular viability depends upon the well-orchestrated functions carried out by numerous protein-coding and non-coding RNAs, as well as RNA-binding proteins. During the last decade, it has become increasingly evident that abnormalities in RNA processing represent a common feature among many neurodegenerative diseases. In "RNAopathies", which include diseases caused by non-coding repeat expansions, RNAs exert toxicity via diverse mechanisms: RNA foci formation, bidirectional transcription, and the production of toxic RNAs and proteins by repeat associated non-ATG translation. The mechanisms of toxicity in "RNA-binding proteinopathies", diseases in which RNA-binding proteins like TDP-43 and FUS play a prominent role, have yet to be fully elucidated. Nonetheless, both loss of function of the RNA binding protein, and a toxic gain of function resulting from its aggregation, are thought to be involved in disease pathogenesis. As part of the special issue on RNA and Splicing Regulation in Neurodegeneration, this review intends to explore the diverse RNA-related mechanisms contributing to neurodegeneration, with a special emphasis on findings emerging from animal models.
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Affiliation(s)
- Veronique V Belzil
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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Seidel K, Siswanto S, Brunt ERP, den Dunnen W, Korf HW, Rüb U. Brain pathology of spinocerebellar ataxias. Acta Neuropathol 2012; 124:1-21. [PMID: 22684686 DOI: 10.1007/s00401-012-1000-x] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/25/2012] [Accepted: 05/25/2012] [Indexed: 12/22/2022]
Abstract
The autosomal dominant cerebellar ataxias (ADCAs) represent a heterogeneous group of neurodegenerative diseases with progressive ataxia and cerebellar degeneration. The current classification of this disease group is based on the underlying genetic defects and their typical disease courses. According to this categorization, ADCAs are divided into the spinocerebellar ataxias (SCAs) with a progressive disease course, and the episodic ataxias (EA) with episodic occurrences of ataxia. The prominent disease symptoms of the currently known and genetically defined 31 SCA types result from damage to the cerebellum and interconnected brain grays and are often accompanied by more specific extra-cerebellar symptoms. In the present review, we report the genetic and clinical background of the known SCAs and present the state of neuropathological investigations of brain tissue from SCA patients in the final disease stages. Recent findings show that the brain is commonly seriously affected in the polyglutamine SCAs (i.e. SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17) and that the patterns of brain damage in these diseases overlap considerably in patients suffering from advanced disease stages. In the more rarely occurring non-polyglutamine SCAs, post-mortem neuropathological data currently are scanty and investigations have been primarily performed in vivo by means of MRI brain imaging. Only a minority of SCAs exhibit symptoms and degenerative patterns allowing for a clear and unambiguous diagnosis of the disease, e.g. retinal degeneration in SCA7, tau aggregation in SCA11, dentate calcification in SCA20, protein depositions in the Purkinje cell layer in SCA31, azoospermia in SCA32, and neurocutaneous phenotype in SCA34. The disease proteins of polyglutamine ataxias and some non-polyglutamine ataxias aggregate as cytoplasmic or intranuclear inclusions and serve as morphological markers. Although inclusions may impair axonal transport, bind transcription factors, and block protein quality control, detailed molecular and pathogenetic consequences remain to be determined.
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Affiliation(s)
- Kay Seidel
- Dr. Senckenbergisches Chronomedizinisches Institut, Goethe University, Theodor-Stern-Kai 7, 60950, Frankfurt/Main, Germany
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Echeverria GV, Cooper TA. RNA-binding proteins in microsatellite expansion disorders: mediators of RNA toxicity. Brain Res 2012; 1462:100-11. [PMID: 22405728 PMCID: PMC3372679 DOI: 10.1016/j.brainres.2012.02.030] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/02/2012] [Accepted: 02/03/2012] [Indexed: 12/22/2022]
Abstract
Although protein-mediated toxicity in neurological disease has been extensively characterized, RNA-mediated toxicity is an emerging mechanism of pathogenesis. In microsatellite expansion disorders, expansion of repeated sequences in noncoding regions gives rise to RNA that produces a toxic gain of function, while expansions in coding regions can disrupt protein function as well as produce toxic RNA. The toxic RNA typically aggregates into nuclear foci and contributes to disease pathogenesis. In many cases, toxicity of the RNA is caused by the disrupted functions of RNA-binding proteins. We will discuss evidence for RNA-mediated toxicity in microsatellite expansion disorders. Different microsatellite expansion disorders are linked with alterations in the same as well as disease-specific RNA-binding proteins. Recent studies have shown that microsatellite expansions can encode multiple repeat-containing toxic RNAs through bidirectional transcription and protein species through repeat-associated non-ATG translation. We will discuss approaches that have characterized the toxic contributions of these various factors.
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Affiliation(s)
- Gloria V. Echeverria
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
| | - Thomas A. Cooper
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030
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The ataxias. Neurogenetics 2012. [DOI: 10.1017/cbo9781139087711.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Tan H, Xu Z, Jin P. Role of noncoding RNAs in trinucleotide repeat neurodegenerative disorders. Exp Neurol 2012; 235:469-75. [PMID: 22309832 DOI: 10.1016/j.expneurol.2012.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 01/11/2012] [Accepted: 01/19/2012] [Indexed: 11/25/2022]
Abstract
Increasingly complex networks of noncoding RNAs are being found to play important and diverse roles in the regulation of gene expression throughout the genome. Many lines of evidence are linking mutations and dysregulations of noncoding RNAs to a host of human diseases, and noncoding RNAs have been implicated in the molecular pathogenesis of some neurodegenerative disorders. The expansion of trinucleotide repeats is now recognized as a major cause of neurological disorders. Here we will review our current knowledge of the proposed mechanisms behind the involvement of noncoding RNAs in the molecular pathogenesis of neurodegenerative disorders, particularly the sequestration of specific RNA-binding proteins, the regulation of antisense transcripts, and the role of the microRNA pathway in the context of known neurodegenerative disorders caused by the expansion of trinucleotide repeats.
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Affiliation(s)
- Huiping Tan
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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Ikeda Y, Ranum LPW, Day JW. Clinical and genetic features of spinocerebellar ataxia type 8. HANDBOOK OF CLINICAL NEUROLOGY 2012; 103:493-505. [PMID: 21827909 DOI: 10.1016/b978-0-444-51892-7.00031-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Yoshio Ikeda
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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Marelli C, Cazeneuve C, Brice A, Stevanin G, Dürr A. Autosomal dominant cerebellar ataxias. Rev Neurol (Paris) 2011; 167:385-400. [PMID: 21546047 DOI: 10.1016/j.neurol.2011.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/27/2011] [Indexed: 12/30/2022]
Abstract
Cerebellar ataxias with autosomal dominant transmission (ADCA) are far rarer than sporadic cases of cerebellar ataxia. The identification of genes involved in dominant forms has confirmed the genetic heterogeneity of these conditions and of the underlying mechanisms and pathways. To date, at least 28 genetic loci and, among them, 20 genes have been identified. In many instances, the phenotype is not restricted to cerebellar dysfunction but includes more complex multisystemic neurological deficits. Seven ADCA (SCA1, 2, 3, 6, 7, 17, and dentatorubro-pallido-luysian atrophy) are caused by repeat expansions in the corresponding proteins; phenotype-genotype correlations have shown that repeat size influences the progression of the disease, its severity and clinical differences among patients, including the phenomenon of anticipation between generations. All other ADCA are caused either by non-coding repeat expansions, conventional mutations or large rearrangements in genes with different functions. This review will focus on the genetic features of ADCA and on the clinical differences among the different forms.
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Affiliation(s)
- C Marelli
- Département de génétique et cytogénétique, consultation de génétique clinique, CHU Pitié-Salpêtrière, AP-HP, 47, boulevard de l'Hôpital, 75013 Paris, France
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Mallik M, Lakhotia SC. Modifiers and mechanisms of multi-system polyglutamine neurodegenerative disorders: lessons from fly models. J Genet 2010; 89:497-526. [DOI: 10.1007/s12041-010-0072-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
Cerebellar ataxias with autosomal dominant transmission are rare, but identification of the associated genes has provided insight into the mechanisms that could underlie other forms of genetic or non-genetic ataxias. In many instances, the phenotype is not restricted to cerebellar dysfunction but includes complex multisystemic neurological deficits. The designation of the loci, SCA for spinocerebellar ataxia, indicates the involvement of at least two systems: the spinal cord and the cerebellum. 11 of 18 known genes are caused by repeat expansions in the corresponding proteins, sharing the same mutational mechanism. All other SCAs are caused by either conventional mutations or large rearrangements in genes with different functions, including glutamate signalling (SCA5/SPTBN2) and calcium signalling (SCA15/16/ITPR1), channel function (SCA13/KCNC3, SCA14/PRKCG, SCA27/FGF14), tau regulation (SCA11/TTBK2), and mitochondrial activity (SCA28/AFG3L2) or RNA alteration (SCA31/BEAN-TK2). The diversity of underlying mechanisms that give rise to the dominant cerebellar ataxias need to be taken into account to identify therapeutic targets.
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Affiliation(s)
- Alexandra Durr
- Université Pierre et Marie Curie-Paris, Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, UMR-S975, Paris, France.
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Li LB, Bonini NM. Roles of trinucleotide-repeat RNA in neurological disease and degeneration. Trends Neurosci 2010; 33:292-8. [PMID: 20398949 DOI: 10.1016/j.tins.2010.03.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2010] [Revised: 03/11/2010] [Accepted: 03/17/2010] [Indexed: 10/19/2022]
Abstract
A large number of human diseases are caused by expansion of repeat sequences - typically trinucleotide repeats - within the respective disease genes. The abnormally expanded sequence can lead to a variety of effects on the gene: sometimes the gene is silenced, but in many cases the expanded repeat sequences confer toxicity to the mRNA and, in the case of polyglutamine diseases, to the encoded protein. This article highlights mechanisms by which the mRNAs with abnormally expanded repeats can confer toxicity leading to neuronal dysfunction and loss. Greater understanding of these mechanisms will provide the foundation for therapeutic advances for this set of human disorders.
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Affiliation(s)
- Ling-Bo Li
- Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA
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