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Feil K, Rattay TW, Adeyemi AK, Goldschagg N, Strupp ML. [What's behind cerebellar dizziness? - News on diagnosis and therapy]. Laryngorhinootologie 2024; 103:337-343. [PMID: 37989215 DOI: 10.1055/a-2192-7278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Vertigo and dizziness comprise a multisensory and multidisciplinary syndrome of different etiologies. The term "cerebellar vertigo and dizziness" comprises a heterogenous group of disorders with clinical signs of cerebellar dysfunction and is caused by vestibulo-cerebellar, vestibulo-spinal or cerebellar systems. About 10 % of patients in an outpatient clinic for vertigo and balance disorders suffer from cerebellar vertigo and dizziness. According to the course of the symptoms, one can considers 3 types: permanent complaints, recurrent episodes of vertigo and balance disorders, or an acute onset of complaints. The most common diagnoses in patients with cerebellar vertigo and dizziness were as follows: degenerative disease, hereditary forms and acquired forms. In a subgroup of patients with cerebellar vertigo, central cerebellar oculomotor dysfunction is indeed the only clinical correlate of the described symptoms. 81 % of patients with cerebellar vertigo suffer from permanent, persistent vertigo and dizziness, 31 % from vertigo attacks, and 21 % from both. Typical clinical cerebellar signs, including gait and limb ataxia or dysarthria, were found less frequently. Key to diagnosis is a focused history as well as a thorough clinical examination with particular attention to oculomotor function. Regarding oculomotor examination, the most common findings were saccadic smooth pursuit, gaze-evoked nystagmus, provocation nystagmus, rebound nystagmus, central fixation nystagmus, most commonly downbeat nystagmus, and disturbances of saccades. Thus, oculomotor examination is very sensitive in diagnosing cerebellar vertigo and dizziness, but not specific in distinguishing different etiologies. Laboratory examinations using posturography and a standardized gait analysis can support the diagnosis, but also help to estimate the risk of falls and to quantify the course and possible symptomatic treatment effects. Patients with cerebellar vertigo and dizziness should receive multimodal treatment.
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Affiliation(s)
- Katharina Feil
- Schwerpunkt neurovaskuläre Erkrankungen, Neurologische Universitätsklinik, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Tim W Rattay
- Schwerpunkt neurodegenerative Erkrankungen, Neurologische Universitätsklinik, Universitätsklinikum Tübingen, Tübingen, Germany
- Hertie-Institut für klinische Hirnforschung, Universitätsklinikum Tübingen, Tübingen
| | - Adedolapo Kamaldeen Adeyemi
- Schwerpunkt neurovaskuläre Erkrankungen, Neurologische Universitätsklinik, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Nicolina Goldschagg
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, München, Germany
- Deutsches Schwindel- und Gleichgewichtszentrum, DSGZ, Ludwig-Maximilians-Universität München, München, Germany
| | - Michael Leo Strupp
- Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, München, Germany
- Deutsches Schwindel- und Gleichgewichtszentrum, DSGZ, Ludwig-Maximilians-Universität München, München, Germany
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2
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Pellerin D, Heindl F, Wilke C, Danzi MC, Traschütz A, Ashton C, Dicaire MJ, Cuillerier A, Del Gobbo G, Boycott KM, Claassen J, Rujescu D, Hartmann AM, Zuchner S, Brais B, Strupp M, Synofzik M. GAA-FGF14 disease: defining its frequency, molecular basis, and 4-aminopyridine response in a large downbeat nystagmus cohort. EBioMedicine 2024; 102:105076. [PMID: 38507876 PMCID: PMC10960126 DOI: 10.1016/j.ebiom.2024.105076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND GAA-FGF14 disease/spinocerebellar ataxia 27B is a recently described neurodegenerative disease caused by (GAA)≥250 expansions in the fibroblast growth factor 14 (FGF14) gene, but its phenotypic spectrum, pathogenic threshold, and evidence-based treatability remain to be established. We report on the frequency of FGF14 (GAA)≥250 and (GAA)200-249 expansions in a large cohort of patients with idiopathic downbeat nystagmus (DBN) and their response to 4-aminopyridine. METHODS Retrospective cohort study of 170 patients with idiopathic DBN, comprising in-depth phenotyping and assessment of 4-aminopyridine treatment response, including re-analysis of placebo-controlled video-oculography treatment response data from a previous randomised double-blind 4-aminopyridine trial. FINDINGS Frequency of FGF14 (GAA)≥250 expansions was 48% (82/170) in patients with idiopathic DBN. Additional cerebellar ocular motor signs were observed in 100% (82/82) and cerebellar ataxia in 43% (35/82) of patients carrying an FGF14 (GAA)≥250 expansion. FGF14 (GAA)200-249 alleles were enriched in patients with DBN (12%; 20/170) compared to controls (0.87%; 19/2191; OR, 15.20; 95% CI, 7.52-30.80; p < 0.0001). The phenotype of patients carrying a (GAA)200-249 allele closely mirrored that of patients carrying a (GAA)≥250 allele. Patients carrying a (GAA)≥250 or a (GAA)200-249 allele had a significantly greater clinician-reported (80%, 33/41 vs 31%, 5/16; RR, 2.58; 95% CI, 1.23-5.41; Fisher's exact test, p = 0.0011) and self-reported (59%, 32/54 vs 11%, 2/19; RR, 5.63; 95% CI, 1.49-21.27; Fisher's exact test, p = 0.00033) response to 4-aminopyridine treatment compared to patients carrying a (GAA)<200 allele. Placebo-controlled video-oculography data, available for four patients carrying an FGF14 (GAA)≥250 expansion, showed a significant decrease in slow phase velocity of DBN with 4-aminopyridine, but not placebo. INTERPRETATION This study confirms that FGF14 GAA expansions are a frequent cause of DBN syndromes. It provides preliminary evidence that (GAA)200-249 alleles might be pathogenic. Finally, it provides large real-world and preliminary piloting placebo-controlled evidence for the efficacy of 4-aminopyridine in GAA-FGF14 disease. FUNDING This work was supported by the Clinician Scientist program "PRECISE.net" funded by the Else Kröner-Fresenius-Stiftung (to CW, AT, and MSy), the grant 779257 "Solve-RD" from the European's Union Horizon 2020 research and innovation program (to MSy), and the grant 01EO 1401 by the German Federal Ministry of Education and Research (BMBF) (to MSt). This work was also supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) N° 441409627, as part of the PROSPAX consortium under the frame of EJP RD, the European Joint Programme on Rare Diseases, under the EJP RD COFUND-EJP N° 825575 (to MSy, BB and-as associated partner-SZ), the NIH National Institute of Neurological Disorders and Stroke (grant 2R01NS072248-11A1 to SZ), the Fondation Groupe Monaco (to BB), and the Montreal General Hospital Foundation (grant PT79418 to BB). The Care4Rare Canada Consortium is funded in part by Genome Canada and the Ontario Genomics Institute (OGI-147 to KMB), the Canadian Institutes of Health Research (CIHR GP1-155867 to KMB), Ontario Research Foundation, Genome Quebec, and the Children's Hospital of Eastern Ontario Foundation. The funders had no role in the conduct of this study.
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Affiliation(s)
- David Pellerin
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, QC, Canada; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, University College London, London, United Kingdom
| | - Felix Heindl
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Carlo Wilke
- Division Translational Genomics of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Tübingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Matt C Danzi
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Andreas Traschütz
- Division Translational Genomics of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Tübingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Catherine Ashton
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, QC, Canada; Department of Neurology, Royal Perth Hospital, Perth, WA, Australia
| | - Marie-Josée Dicaire
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, QC, Canada
| | - Alexanne Cuillerier
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Giulia Del Gobbo
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Jens Claassen
- Department of Neurology, University Hospital Essen, University Duisburg-Essen, Essen, Germany; MediClin Klinik Reichshof, Reichshof-Eckenhagen, Germany
| | - Dan Rujescu
- Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Vienna, Austria
| | - Annette M Hartmann
- Department of Psychiatry and Psychotherapy, Comprehensive Center for Clinical Neurosciences and Mental Health (C3NMH), Medical University of Vienna, Vienna, Austria
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, QC, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada; Centre de Réadaptation Lucie-Bruneau, Montreal, QC, Canada
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, University Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Matthis Synofzik
- Division Translational Genomics of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Tübingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany.
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3
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de Sousa FA, Alves CS, Pinto AN, Meireles L, Rego ÂR. Pharmacological Treatment of Acute Unilateral Vestibulopathy: A Review. J Audiol Otol 2024; 28:18-28. [PMID: 37953517 PMCID: PMC10808386 DOI: 10.7874/jao.2023.00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/18/2023] [Accepted: 06/22/2023] [Indexed: 11/14/2023] Open
Abstract
There have been few investigations on the epidemiology, etiology, and medical management of acute unilateral vestibulopathy (AUV). Short-term pharmaceutical resolutions include vestibular symptomatic suppressants, anti-emetics, and some cause-based therapies. Anticholinergics, phenothiazines, antihistamines, antidopaminergics, benzodiazepines, and calcium channel antagonists are examples of vestibular suppressants. Some of these medications may show their effects through multiple mechanisms. In contrast, N-acetyl-L-leucine, Ginkgo biloba, and betahistine improve central vestibular compensation. Currently, AUV pathophysiology is poorly understood. Diverse hypotheses have previously been identified which have brought about some causal treatments presently used. According to some publications, acute administration of anti-inflammatory medications may have a deleterious impact on both post-lesional functional recovery and endogenous adaptive plasticity processes. Thus, some authors do not recommend the use of corticosteroids in AUV. Antivirals are even more contentious in the context of AUV treatment. Although vascular theories have been presented, no verified investigations employing anti-clotting or vasodilator medications have been conducted. There are no standardized treatment protocols for AUV to date, and the pharmacological treatment of AUV is still questionable. This review addresses the most current developments and controversies in AUV medical treatment.
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Affiliation(s)
- Francisco Alves de Sousa
- Otorhinolaryngology and Head & Neck Surgery Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Clara Serdoura Alves
- Otorhinolaryngology and Head & Neck Surgery Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Ana Nóbrega Pinto
- Otorhinolaryngology and Head & Neck Surgery Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Luís Meireles
- Otorhinolaryngology and Head & Neck Surgery Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Ângela Reis Rego
- Otorhinolaryngology and Head & Neck Surgery Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
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Pellerin D, Danzi MC, Renaud M, Houlden H, Synofzik M, Zuchner S, Brais B. Spinocerebellar ataxia 27B: A novel, frequent and potentially treatable ataxia. Clin Transl Med 2024; 14:e1504. [PMID: 38279833 PMCID: PMC10819088 DOI: 10.1002/ctm2.1504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/19/2023] [Accepted: 11/24/2023] [Indexed: 01/29/2024] Open
Abstract
Hereditary ataxias, especially when presenting sporadically in adulthood, present a particular diagnostic challenge owing to their great clinical and genetic heterogeneity. Currently, up to 75% of such patients remain without a genetic diagnosis. In an era of emerging disease-modifying gene-stratified therapies, the identification of causative alleles has become increasingly important. Over the past few years, the implementation of advanced bioinformatics tools and long-read sequencing has allowed the identification of a number of novel repeat expansion disorders, such as the recently described spinocerebellar ataxia 27B (SCA27B) caused by a (GAA)•(TTC) repeat expansion in intron 1 of the fibroblast growth factor 14 (FGF14) gene. SCA27B is rapidly gaining recognition as one of the most common forms of adult-onset hereditary ataxia, with several studies showing that it accounts for a substantial number (9-61%) of previously undiagnosed cases from different cohorts. First natural history studies and multiple reports have already outlined the progression and core phenotype of this novel disease, which consists of a late-onset slowly progressive pan-cerebellar syndrome that is frequently associated with cerebellar oculomotor signs, such as downbeat nystagmus, and episodic symptoms. Furthermore, preliminary studies in patients with SCA27B have shown promising symptomatic benefits of 4-aminopyridine, an already marketed drug. This review describes the current knowledge of the genetic and molecular basis, epidemiology, clinical features and prospective treatment strategies in SCA27B.
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Affiliation(s)
- David Pellerin
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and InstituteMcGill UniversityMontrealQuebecCanada
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryUniversity College LondonLondonUK
| | - Matt C. Danzi
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human GenomicsUniversity of Miami Miller School of MedicineMiamiFloridaUSA
| | - Mathilde Renaud
- INSERM‐U1256 NGEREUniversité de LorraineNancyFrance
- Service de Neurologie, CHRU de NancyNancyFrance
- Service de Génétique Clinique, CHRU de NancyNancyFrance
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryUniversity College LondonLondonUK
| | - Matthis Synofzik
- Division of Translational Genomics of Neurodegenerative DiseasesHertie‐Institute for Clinical Brain Research and Center of Neurology, University of TübingenTübingenGermany
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human GenomicsUniversity of Miami Miller School of MedicineMiamiFloridaUSA
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and InstituteMcGill UniversityMontrealQuebecCanada
- Department of Human GeneticsMcGill UniversityMontrealQuebecCanada
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5
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van der Heijden ME, Sillitoe RV. Cerebellar dysfunction in rodent models with dystonia, tremor, and ataxia. DYSTONIA 2023; 2:11515. [PMID: 38105800 PMCID: PMC10722573 DOI: 10.3389/dyst.2023.11515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Dystonia is a movement disorder characterized by involuntary co- or over-contractions of the muscles, which results in abnormal postures and movements. These symptoms arise from the pathophysiology of a brain-wide dystonia network. There is mounting evidence suggesting that the cerebellum is a central node in this network. For example, manipulations that target the cerebellum cause dystonic symptoms in mice, and cerebellar neuromodulation reduces these symptoms. Although numerous findings provide insight into dystonia pathophysiology, they also raise further questions. Namely, how does cerebellar pathophysiology cause the diverse motor abnormalities in dystonia, tremor, and ataxia? Here, we describe recent work in rodents showing that distinct cerebellar circuit abnormalities could define different disorders and we discuss potential mechanisms that determine the behavioral presentation of cerebellar diseases.
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Affiliation(s)
- Meike E. van der Heijden
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX, United States
| | - Roy V. Sillitoe
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
- Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX, United States
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Erickson JD, Kyllo T, Wulff H. Ca 2+-regulated expression of high affinity methylaminoisobutryic acid transport in hippocampal neurons inhibited by riluzole and novel neuroprotective aminothiazoles. Curr Res Physiol 2023; 6:100109. [PMID: 38107787 PMCID: PMC10724208 DOI: 10.1016/j.crphys.2023.100109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/13/2023] [Accepted: 09/27/2023] [Indexed: 12/19/2023] Open
Abstract
High affinity methylaminoisobutyric acid(MeAIB)/glutamine(Gln) transport activity regulated by neuronal firing occurs at the plasma membrane in mature rat hippocampal neuron-enriched cultures. Spontaneous Ca2+-regulated transport activity was similarly inhibited by riluzole, a benzothiazole anticonvulsant agent, and by novel naphthalenyl substituted aminothiazole derivatives such as SKA-378. Here, we report that spontaneous transport activity is stimulated by 4-aminopyridine (4-AP) and that phorbol-myristate acetate (PMA) increases high K+ stimulated transport activity that is inhibited by staurosporine. 4-AP-stimulated spontaneous and PMA-stimulated high K+-induced transport is not present at 7 days in vitro (DIV) and is maximal by DIV∼21. The relative affinity for MeAIB is similar for spontaneous and high K+-stimulated transport (Km ∼ 50 μM) suggesting that a single transporter is involved. While riluzole and SKA-378 inhibit spontaneous transport with equal potency (IC50 ∼ 1 μM), they exhibit decreased (∼3-5 X) potency for 4-AP-stimulated spontaneous transport. Interestingly, high K+-stimulated MeAIB transport displays lower and differential sensitivity to the two compounds. SKA-378-related halogenated derivatives of SKA-75 (SKA-219, SKA-377 and SKA-375) preferentially inhibit high K+-induced expression of MeAIB transport activity at the plasma membrane (IC50 < 25 μM), compared to SKA-75 and riluzole (IC50 > 100 μM). Ca2+-dependent spontaneous and high K+-stimulated MeAIB transport activity is blocked by ω-conotoxin MVIIC, ω-agatoxin IVA, ω-agatoxin TK (IC50 ∼ 500 nM) or cadmium ion (IC50 ∼ 20 μM) demonstrating that P/Q-type CaV channels that are required for activity-regulated presynaptic vesicular glutamate (Glu) release are also required for high-affinity MeAIB transport expression at the plasma membrane. We suggest that neural activity driven and Ca2+ dependent trafficking of the high affinity MeAIB transporter to the plasma membrane is a unique target to understand mechanisms of Glu/Gln recycling in synapses and acute neuroprotection against excitotoxic presynaptic Glu induced neural injury.
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Affiliation(s)
- Jeffrey D. Erickson
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health-New Orleans, New Orleans, LA, USA
| | - Thomas Kyllo
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health-New Orleans, New Orleans, LA, USA
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California-Davis, Davis, CA, USA
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7
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Bremova-Ertl T, Hofmann J, Stucki J, Vossenkaul A, Gautschi M. Inborn Errors of Metabolism with Ataxia: Current and Future Treatment Options. Cells 2023; 12:2314. [PMID: 37759536 PMCID: PMC10527548 DOI: 10.3390/cells12182314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/09/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
A number of hereditary ataxias are caused by inborn errors of metabolism (IEM), most of which are highly heterogeneous in their clinical presentation. Prompt diagnosis is important because disease-specific therapies may be available. In this review, we offer a comprehensive overview of metabolic ataxias summarized by disease, highlighting novel clinical trials and emerging therapies with a particular emphasis on first-in-human gene therapies. We present disease-specific treatments if they exist and review the current evidence for symptomatic treatments of these highly heterogeneous diseases (where cerebellar ataxia is part of their phenotype) that aim to improve the disease burden and enhance quality of life. In general, a multimodal and holistic approach to the treatment of cerebellar ataxia, irrespective of etiology, is necessary to offer the best medical care. Physical therapy and speech and occupational therapy are obligatory. Genetic counseling is essential for making informed decisions about family planning.
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Affiliation(s)
- Tatiana Bremova-Ertl
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland; (J.H.); (J.S.)
- Center for Rare Diseases, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland
| | - Jan Hofmann
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland; (J.H.); (J.S.)
| | - Janine Stucki
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland; (J.H.); (J.S.)
| | - Anja Vossenkaul
- Division of Pediatric Endocrinology, Diabetes and Metabolism, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland; (A.V.); (M.G.)
| | - Matthias Gautschi
- Division of Pediatric Endocrinology, Diabetes and Metabolism, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland; (A.V.); (M.G.)
- Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
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8
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Pellerin D, Heindl F, Wilke C, Danzi MC, Traschütz A, Ashton C, Dicaire MJ, Cuillerier A, Del Gobbo G, Boycott KM, Claassen J, Rujescu D, Hartmann AM, Zuchner S, Brais B, Strupp M, Synofzik M. Intronic FGF14 GAA repeat expansions are a common cause of downbeat nystagmus syndromes: frequency, phenotypic profile, and 4-aminopyridine treatment response. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.07.30.23293380. [PMID: 37577458 PMCID: PMC10418564 DOI: 10.1101/2023.07.30.23293380] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The cause of downbeat nystagmus (DBN) remains unknown in approximately 30% of patients (idiopathic DBN). Here, we hypothesized that: (i) FGF14 (GAA) ≥250 repeat expansions represent a frequent genetic cause of idiopathic DBN syndromes, (ii) are treatable with 4-aminopyridine (4-AP), and (iii) FGF14 (GAA) 200-249 alleles are potentially pathogenic. We conducted a multi-modal cohort study of 170 patients with idiopathic DBN that comprised: in-depth ocular motor, neurological, and disease evolution phenotyping; assessment of 4-AP treatment response, including re-analysis of placebo-controlled video-oculography treatment response data from a previous randomized double-blind 4-AP trial; and genotyping of the FGF14 repeat. Frequency of FGF14 (GAA) ≥250 expansions was 48% (82/170) in the entire idiopathic DBN cohort. Additional cerebellar ocular motor signs were observed in 100% (82/82), cerebellar ataxia in 43% (35/82), and extracerebellar features in 21% (17/82) of (GAA) ≥250 - FGF14 patients. Alleles of 200 to 249 GAA repeats were enriched in patients with DBN (12%; 20/170) compared to controls (0.87%; 19/2,191; OR, 15.20; 95% CI, 7.52-30.80; p =9.876e-14). The phenotype of (GAA) 200-249 - FGF14 patients closely mirrored that of (GAA) ≥250 - FGF14 patients. (GAA) ≥250 - FGF14 and (GAA) 200-249 - FGF14 patients had a significantly greater clinician-reported (80% vs 31%; p =0.0011) and self-reported (59% vs 11%; p =0.0003) response rate to 4-AP treatment compared to (GAA) <200 - FGF14 patients. This included a treatment response with high relevance to everyday living, as exemplified by an improvement of 2 FARS stages in some cases. Placebo-controlled video-oculography data of four (GAA) ≥250 - FGF14 patients previously enrolled in a 4-AP randomized double-blind trial showed a significant decrease in slow phase velocity of DBN with 4-AP, but not placebo. This study shows that FGF14 GAA repeat expansions are a highly frequent genetic cause of DBN syndromes, especially when associated with additional cerebellar features. Moreover, they genetically stratify a subgroup of patients with DBN that appear to be highly responsive to 4-AP, thus paving the way for a "theranostics" approach in DBN syndromes.
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9
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Marinina KS, Bezprozvanny IB, Egorova PA. A chlorzoxazone-folic acid combination improves cognitive affective decline in SCA2-58Q mice. Sci Rep 2023; 13:12588. [PMID: 37537226 PMCID: PMC10400576 DOI: 10.1038/s41598-023-39331-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/24/2023] [Indexed: 08/05/2023] Open
Abstract
Spinocerebellar ataxia type 2 (SCA2) is a polyglutamine disorder caused by a pathological expansion of CAG repeats in ATXN2 gene. SCA2 is accompanied by cerebellar degeneration and progressive motor decline. Cerebellar Purkinje cells (PCs) seem to be primarily affected in this disorder. The majority of the ataxia research is focused on the motor decline observed in ataxic patients and animal models of the disease. However, recent evidence from patients and ataxic mice suggests that SCA2 can also share the symptoms of the cerebellar cognitive affective syndrome. We previously reported that SCA2-58Q PC-specific transgenic mice exhibit anxiolytic behavior, decline in spatial memory, and a depressive-like state. Here we studied the effect of the activation of the small conductance calcium-activated potassium channels (SK channels) by chlorzoxazone (CHZ) combined with the folic acid (FA) on the PC firing and also motor, cognitive and affective symptoms in SCA2-58Q mice. We realized that CHZ-FA combination improved motor and cognitive decline as well as ameliorated mood alterations in SCA2-58Q mice without affecting the firing rate of their cerebellar PCs. Our results support the idea of the combination therapy for both ataxia and non-motor symptoms in ataxic mice without affecting the firing frequency of PCs.
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Affiliation(s)
- Ksenia S Marinina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.
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10
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Huang H, Shakkottai VG. Targeting Ion Channels and Purkinje Neuron Intrinsic Membrane Excitability as a Therapeutic Strategy for Cerebellar Ataxia. Life (Basel) 2023; 13:1350. [PMID: 37374132 DOI: 10.3390/life13061350] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/03/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
In degenerative neurological disorders such as Parkinson's disease, a convergence of widely varying insults results in a loss of dopaminergic neurons and, thus, the motor symptoms of the disease. Dopamine replacement therapy with agents such as levodopa is a mainstay of therapy. Cerebellar ataxias, a heterogeneous group of currently untreatable conditions, have not been identified to have a shared physiology that is a target of therapy. In this review, we propose that perturbations in cerebellar Purkinje neuron intrinsic membrane excitability, a result of ion channel dysregulation, is a common pathophysiologic mechanism that drives motor impairment and vulnerability to degeneration in cerebellar ataxias of widely differing genetic etiologies. We further propose that treatments aimed at restoring Purkinje neuron intrinsic membrane excitability have the potential to be a shared therapy in cerebellar ataxia akin to levodopa for Parkinson's disease.
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Affiliation(s)
- Haoran Huang
- Medical Scientist Training Program, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Vikram G Shakkottai
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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11
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Rey Hipolito AG, van der Heijden ME, Sillitoe RV. Physiology of Dystonia: Animal Studies. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 169:163-215. [PMID: 37482392 DOI: 10.1016/bs.irn.2023.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Dystonia is currently ranked as the third most prevalent motor disorder. It is typically characterized by involuntary muscle over- or co-contractions that can cause painful abnormal postures and jerky movements. Dystonia is a heterogenous disorder-across patients, dystonic symptoms vary in their severity, body distribution, temporal pattern, onset, and progression. There are also a growing number of genes that are associated with hereditary dystonia. In addition, multiple brain regions are associated with dystonic symptoms in both genetic and sporadic forms of the disease. The heterogeneity of dystonia has made it difficult to fully understand its underlying pathophysiology. However, the use of animal models has been used to uncover the complex circuit mechanisms that lead to dystonic behaviors. Here, we summarize findings from animal models harboring mutations in dystonia-associated genes and phenotypic animal models with overt dystonic motor signs resulting from spontaneous mutations, neural circuit perturbations, or pharmacological manipulations. Taken together, an emerging picture depicts dystonia as a result of brain-wide network dysfunction driven by basal ganglia and cerebellar dysfunction. In the basal ganglia, changes in dopaminergic, serotonergic, noradrenergic, and cholinergic signaling are found across different animal models. In the cerebellum, abnormal burst firing activity is observed in multiple dystonia models. We are now beginning to unveil the extent to which these structures mechanistically interact with each other. Such mechanisms inspire the use of pre-clinical animal models that will be used to design new therapies including drug treatments and brain stimulation.
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Affiliation(s)
- Alejandro G Rey Hipolito
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, United States
| | - Meike E van der Heijden
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, United States
| | - Roy V Sillitoe
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States; Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX, United States; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, United States.
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12
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Folacci M, Estaran S, Ménard C, Bertaud A, Rousset M, Roussel J, Thibaud JB, Vignes M, Chavanieu A, Charnet P, Cens T. Functional Characterization of Four Known Cav2.1 Variants Associated with Neurodevelopmental Disorders. MEMBRANES 2023; 13:96. [PMID: 36676903 PMCID: PMC9864995 DOI: 10.3390/membranes13010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Cav2.1 channels are expressed throughout the brain and are the predominant Ca2+ channels in the Purkinje cells. These cerebellar neurons fire spontaneously, and Cav2.1 channels are involved in the regular pacemaking activity. The loss of precision of the firing pattern of Purkinje cells leads to ataxia, a disorder characterized by poor balance and difficulties in performing coordinated movements. In this study, we aimed at characterizing functional and structural consequences of four variations (p.A405T in I-II loop and p.R1359W, p.R1667W and p.S1799L in IIIS4, IVS4, and IVS6 helices, respectively) identified in patients exhibiting a wide spectrum of disorders including ataxia symptoms. Functional analysis using two major Cav2.1 splice variants (Cav2.1+e47 and Cav2.1-e47) in Xenopus laevis oocytes, revealed a lack of effect upon A405T substitution and a significant loss-of-function caused by R1359W, whereas R1667W and S1799L caused both channel gain-of-function and loss-of-function, in a splice variant-dependent manner. Structural analysis revealed the loss of interactions with S1, S2, and S3 helices upon R1359W and R1667W substitutions, but a lack of obvious structural changes with S1799L. Computational modeling suggests that biophysical changes induced by Cav2.1 pathogenic mutations might affect action potential frequency in Purkinje cells.
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13
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Mukherjee S, Cassini TA, Hu N, Yang T, Li B, Shen W, Moth CW, Rinker DC, Sheehan JH, Cogan JD, Newman JH, Hamid R, Macdonald RL, Roden DM, Meiler J, Kuenze G, Phillips JA, Capra JA. Personalized structural biology reveals the molecular mechanisms underlying heterogeneous epileptic phenotypes caused by de novo KCNC2 variants. HGG ADVANCES 2022; 3:100131. [PMID: 36035247 PMCID: PMC9399384 DOI: 10.1016/j.xhgg.2022.100131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/11/2022] [Indexed: 11/28/2022] Open
Abstract
Whole-exome sequencing (WES) in the clinic has identified several rare monogenic developmental and epileptic encephalopathies (DEE) caused by ion channel variants. However, WES often fails to provide actionable insight for rare diseases, such as DEEs, due to the challenges of interpreting variants of unknown significance (VUS). Here, we describe a "personalized structural biology" (PSB) approach that leverages recent innovations in the analysis of protein 3D structures to address this challenge. We illustrate this approach in an Undiagnosed Diseases Network (UDN) individual with DEE symptoms and a de novo VUS in KCNC2 (p.V469L), the Kv3.2 voltage-gated potassium channel. A nearby KCNC2 variant (p.V471L) was recently suggested to cause DEE-like phenotypes. Computational structural modeling suggests that both affect protein function. However, despite their proximity, the p.V469L variant is likely to sterically block the channel pore, while the p.V471L variant is likely to stabilize the open state. Biochemical and electrophysiological analyses demonstrate heterogeneous loss-of-function and gain-of-function effects, as well as differential response to 4-aminopyridine treatment. Molecular dynamics simulations illustrate that the pore of the p.V469L variant is more constricted, increasing the energetic barrier for K+ permeation, whereas the p.V471L variant stabilizes the open conformation. Our results implicate variants in KCNC2 as causative for DEE and guide the interpretation of a UDN individual. They further delineate the molecular basis for the heterogeneous clinical phenotypes resulting from two proximal pathogenic variants. This demonstrates how the PSB approach can provide an analytical framework for individualized hypothesis-driven interpretation of protein-coding VUS.
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Affiliation(s)
- Souhrid Mukherjee
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Thomas A. Cassini
- Department of Internal Medicine, National Institutes of Health Clinical Center, Bethesda, MD 20814, USA
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Tao Yang
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Bian Li
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christopher W. Moth
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - David C. Rinker
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Jonathan H. Sheehan
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- John T. Milliken Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joy D. Cogan
- Department of Pediatrics, Division of Medical Genetics and Genomic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Undiagnosed Diseases Network
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Department of Pediatrics, Division of Medical Genetics and Genomic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Pulmonary Hypertension Center, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- John T. Milliken Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Internal Medicine, National Institutes of Health Clinical Center, Bethesda, MD 20814, USA
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, SAC 04103, Germany
- Department of Chemistry, Leipzig University, Leipzig, SAC 04109, Germany
- Department of Computer Science, Leipzig University, Leipzig, SAC 04109, Germany
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Bakar Computational Health Sciences Institute and Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - John H. Newman
- Pulmonary Hypertension Center, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rizwan Hamid
- Department of Pediatrics, Division of Medical Genetics and Genomic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Robert L. Macdonald
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Dan M. Roden
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, SAC 04103, Germany
- Department of Chemistry, Leipzig University, Leipzig, SAC 04109, Germany
- Department of Computer Science, Leipzig University, Leipzig, SAC 04109, Germany
| | - Georg Kuenze
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, SAC 04103, Germany
| | - John A. Phillips
- Department of Pediatrics, Division of Medical Genetics and Genomic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - John A. Capra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Bakar Computational Health Sciences Institute and Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA 94143, USA
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14
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Egorova PA, Bezprozvanny IB. Electrophysiological Studies Support Utility of Positive Modulators of SK Channels for the Treatment of Spinocerebellar Ataxia Type 2. CEREBELLUM (LONDON, ENGLAND) 2022; 21:742-749. [PMID: 34978024 DOI: 10.1007/s12311-021-01349-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/18/2021] [Indexed: 06/14/2023]
Abstract
Spinocerebellar ataxia type 2 (SCA2) is an incurable hereditary disorder accompanied by cerebellar degeneration following ataxic symptoms. The causative gene for SCA2 is ATXN2. The ataxin-2 protein is involved in RNA metabolism; the polyQ expansion may interrupt ataxin-2 interaction with its molecular targets, thus representing a loss-of-function mutation. However, mutant ataxin-2 protein also displays the features of gain-of-function mutation since it forms the aggregates in SCA2 cells and also enhances the IP3-induced calcium release in affected neurons. The cerebellar Purkinje cells (PCs) are primarily affected in SCA2. Their tonic pacemaker activity is crucial for the proper cerebellar functioning. Disturbances in PC pacemaking are observed in many ataxic disorders. The abnormal intrinsic pacemaking was reported in mouse models of episodic ataxia type 2 (EA2), SCA1, SCA2, SCA3, SCA6, Huntington's disease (HD), and in some other murine models of the disorders associated with the cerebellar degeneration. In our studies using SCA2-58Q transgenic mice via cerebellar slice recording and in vivo recording from urethane-anesthetized mice and awake head-fixed mice, we have demonstrated the impaired firing frequency and irregularity of PCs in these mice. PC pacemaker activity is regulated by SK channels. The pharmacological activation of SK channels has demonstrated some promising results in the electrophysiological experiments on EA2, SCA1, SCA2, SCA3, SCA6, HD mice, and also on mutant CACNA1A mice. In our studies, we have reported that the SK activators CyPPA and NS309 converted bursting activity into tonic, while oral treatment with CyPPA and NS13001 significantly improved motor performance and PC morphology in SCA2 mice. The i.p. injections of chlorzoxazone (CHZ) during in vivo recording sessions converted bursting cells into tonic in anesthetized SCA2 mice. And, finally, long-term injections of CHZ recovered the precision of PC pacemaking activity in awake SCA2 mice and alleviated their motor decline. Thus, the SK activation can be used as a potential way to treat SCA2 and other diseases accompanied by cerebellar degeneration.
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Affiliation(s)
- Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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15
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Chang HHV, Cook AA, Watt AJ, Cullen KE. Loss of Flocculus Purkinje Cell Firing Precision Leads to Impaired Gaze Stabilization in a Mouse Model of Spinocerebellar Ataxia Type 6 (SCA6). Cells 2022; 11:cells11172739. [PMID: 36078147 PMCID: PMC9454745 DOI: 10.3390/cells11172739] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Spinocerebellar Ataxia Type 6 (SCA6) is a mid-life onset neurodegenerative disease characterized by progressive ataxia, dysarthria, and eye movement impairment. This autosomal dominant disease is caused by the expansion of a CAG repeat tract in the CACNA1A gene that encodes the α1A subunit of the P/Q type voltage-gated Ca2+ channel. Mouse models of SCA6 demonstrate impaired locomotive function and reduced firing precision of cerebellar Purkinje in the anterior vermis. Here, to further assess deficits in other cerebellar-dependent behaviors, we characterized the oculomotor phenotype of a knock-in mouse model with hyper-expanded polyQ repeats (SCA684Q). We found a reduction in the efficacy of the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) in SCA6 mutant mice, without a change in phase, compared to their litter-matched controls. Additionally, VOR motor learning was significantly impaired in SCA684Q mice. Given that the floccular lobe of the cerebellum plays a vital role in the generation of OKR and VOR calibration and motor learning, we investigated the firing behavior and morphology of floccular cerebellar Purkinje cells. Overall, we found a reduction in the firing precision of floccular lobe Purkinje cells but no morphological difference between SCA684Q and wild-type mice. Taken together, our findings establish that gaze stabilization and motor learning are impaired in SCA684Q mice and suggest that altered cerebellar output contributes to these deficits.
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Affiliation(s)
| | - Anna A. Cook
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Alanna J. Watt
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA
- Correspondence:
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16
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Mayoral-Palarz K, Neves-Carvalho A, Duarte-Silva S, Monteiro-Fernandes D, Maciel P, Khodakhah K. Cerebellar neuronal dysfunction accompanies early motor symptoms in spinocerebellar ataxia type 3. Dis Model Mech 2022; 15:275597. [PMID: 35660856 PMCID: PMC9367011 DOI: 10.1242/dmm.049514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/25/2022] [Indexed: 11/30/2022] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is an adult-onset, progressive ataxia. SCA3 presents with ataxia before any gross neuropathology. A feature of many cerebellar ataxias is aberrant cerebellar output that contributes to motor dysfunction. We examined whether abnormal cerebellar output was present in the CMVMJD135 SCA3 mouse model and, if so, whether it correlated with the disease onset and progression. In vivo recordings showed that the activity of deep cerebellar nuclei neurons, the main output of the cerebellum, was altered. The aberrant activity correlated with the onset of ataxia. However, although the severity of ataxia increased with age, the severity of the aberrant cerebellar output was not progressive. The abnormal cerebellar output, however, was accompanied by non-progressive abnormal activity of their upstream synaptic inputs, the Purkinje cells. In vitro recordings indicated that alterations in intrinsic Purkinje cell pacemaking and in their synaptic inputs contributed to abnormal Purkinje cell activity. These findings implicate abnormal cerebellar physiology as an early, consistent contributor to pathophysiology in SCA3, and suggest that the aberrant cerebellar output could be an appropriate therapeutic target in SCA3. Summary: In a mouse model of spinocerebellar ataxia type 3 (SCA3), aberrant cerebellar physiology is apparent early in disease, prior to cerebellar neuronal pathology. Aberrant cerebellar output could be a therapeutic target in SCA3.
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Affiliation(s)
- Kristin Mayoral-Palarz
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Andreia Neves-Carvalho
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.,Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Sara Duarte-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Daniela Monteiro-Fernandes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Kamran Khodakhah
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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17
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Snell HD, Vitenzon A, Tara E, Chen C, Tindi J, Jordan BA, Khodakhah K. Mechanism of stress-induced attacks in an episodic neurologic disorder. SCIENCE ADVANCES 2022; 8:eabh2675. [PMID: 35442745 PMCID: PMC9020779 DOI: 10.1126/sciadv.abh2675] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/02/2022] [Indexed: 05/21/2023]
Abstract
Stress is the most common trigger among episodic neurologic disorders. In episodic ataxia type 2 (EA2), physical or emotional stress causes episodes of severe motor dysfunction that manifest as ataxia and dystonia. We used the tottering (tg/tg) mouse, a faithful animal model of EA2, to dissect the mechanisms underlying stress-induced motor attacks. We find that in response to acute stress, activation of α1-adrenergic receptors (α1-Rs) on Purkinje cells by norepinephrine leads to their erratic firing and consequently motor attacks. We show that norepinephrine induces erratic firing of Purkinje cells by disrupting their spontaneous intrinsic pacemaking via a casein kinase 2 (CK2)-dependent signaling pathway, which likely reduces the activity of calcium-dependent potassium channels. Moreover, we report that disruption of this signaling cascade at a number of nodes prevents stress-induced attacks in the tottering mouse. Together, our results suggest that norepinephrine and CK2 are required for the initiation of stress-induced attacks in EA2 and provide previously unidentified targets for therapeutic intervention.
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Affiliation(s)
- Heather D. Snell
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ariel Vitenzon
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Esra Tara
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Chris Chen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jaafar Tindi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Bryen A. Jordan
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Psychiatry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kamran Khodakhah
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Psychiatry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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18
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Acute Cerebellar Inflammation and Related Ataxia: Mechanisms and Pathophysiology. Brain Sci 2022; 12:brainsci12030367. [PMID: 35326323 PMCID: PMC8946185 DOI: 10.3390/brainsci12030367] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/11/2022] Open
Abstract
The cerebellum governs motor coordination and motor learning. Infection with external microorganisms, such as viruses, bacteria, and fungi, induces the release and production of inflammatory mediators, which drive acute cerebellar inflammation. The clinical observation of acute cerebellitis is associated with the emergence of cerebellar ataxia. In our animal model of the acute inflammation of the cerebellar cortex, animals did not show any ataxia but hyperexcitability in the cerebellar cortex and depression-like behaviors. In contrast, animal models with neurodegeneration of the cerebellar Purkinje cells and hypoexcitability of the neurons show cerebellar ataxia. The suppression of the Ca2+-activated K+ channels in vivo is associated with a type of ataxia. Therefore, there is a gap in our interpretation between the very early phase of cerebellar inflammation and the emergence of cerebellar ataxia. In this review, we discuss the hypothesized scenario concerning the emergence of cerebellar ataxia. First, compared with genetically induced cerebellar ataxias, we introduce infection and inflammation in the cerebellum via aberrant immunity and glial responses. Especially, we focus on infections with cytomegalovirus, influenza virus, dengue virus, and SARS-CoV-2, potential relevance to mitochondrial DNA, and autoimmunity in infection. Second, we review neurophysiological modulation (intrinsic excitability, excitatory, and inhibitory synaptic transmission) by inflammatory mediators and aberrant immunity. Next, we discuss the cerebellar circuit dysfunction (presumably, via maintaining the homeostatic property). Lastly, we propose the mechanism of the cerebellar ataxia and possible treatments for the ataxia in the cerebellar inflammation.
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Impact of Purkinje Cell Simple Spike Synchrony on Signal Transmission from Flocculus. THE CEREBELLUM 2021; 21:879-904. [PMID: 34665396 DOI: 10.1007/s12311-021-01332-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
Purkinje cells (PCs) in the cerebellar flocculus carry rate-coded information that ultimately drives eye movement. Floccular PCs lying nearby each other exhibit partial synchrony of their simple spikes (SS). Elsewhere in the cerebellum, PC SS synchrony has been demonstrated to influence activity of the PCs' synaptic targets, and some suggest it constitutes another vector for information transfer. We investigated in the cerebellar flocculus the extent to which the rate code and PC synchrony interact. One motivation for the study was to explain the cerebellar deficits in ataxic mice like tottering; we speculated that PC synchrony has a positive effect on rate code transmission that is lost in the mutants. Working in transgenic mice whose PCs express channelrhodopsin, we exploited a property of optogenetics to control PC synchrony: pulsed photostimulation engenders stimulus-locked spiking, whereas continuous photostimulation engenders spiking whose timing is unconstrained. We photoactivated flocculus PCs using pulsed stimuli with sinusoidally varying timing vs. continuous stimuli with sinusoidally varying intensity. Recordings of PC pairs confirmed that pulsed stimuli engendered greater PC synchrony. We quantified the efficiency of transmission of the evoked PC firing rate modulation from the amplitudes of firing rate modulation and eye movement. Rate code transmission was slightly poorer in the conditions that generated greater PC synchrony, arguing against our motivating speculation regarding the origin of ataxia in tottering. Floccular optogenetic stimulation prominently augmented a 250-300 Hz local field potential oscillation, and we demonstrate relationships between the oscillation power and the evoked PC synchrony.
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A Novel KCNA2 Variant in a Patient with Non-Progressive Congenital Ataxia and Epilepsy: Functional Characterization and Sensitivity to 4-Aminopyridine. Int J Mol Sci 2021; 22:ijms22189913. [PMID: 34576077 PMCID: PMC8469797 DOI: 10.3390/ijms22189913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/02/2021] [Accepted: 09/08/2021] [Indexed: 12/26/2022] Open
Abstract
Kv1.2 channels, encoded by the KCNA2 gene, are localized in the central and peripheral nervous system, where they regulate neuronal excitability. Recently, heterozygous mutations in KCNA2 have been associated with a spectrum of symptoms extending from epileptic encephalopathy, intellectual disability, and cerebellar ataxia. Patients are treated with a combination of antiepileptic drugs and 4-aminopyridine (4-AP) has been recently trialed in specific cases. We identified a novel variant in KCNA2, E236K, in a Serbian proband with non-progressive congenital ataxia and early onset epilepsy, treated with sodium valproate. To ascertain the pathogenicity of E236K mutation and to verify its sensitivity to 4-AP, we transfected HEK 293 cells with Kv1.2 WT or E236K cDNAs and recorded potassium currents through the whole-cell patch-clamp. In silico analysis supported the electrophysiological data. E236K channels showed voltage-dependent activation shifted towards negative potentials and slower kinetics of deactivation and activation compared with Kv1.2 WT. Heteromeric Kv1.2 WT+E236K channels, resembling the condition of the heterozygous patient, confirmed a mixed gain- and loss-of-function (GoF/LoF) biophysical phenotype. 4-AP inhibited both Kv1.2 and E236K channels with similar potency. Homology modeling studies of mutant channels suggested a reduced interaction between the residue K236 in the S2 segment and the gating charges at S4. Overall, the biophysical phenotype of E236K channels correlates with the mild end of the clinical spectrum reported in patients with GoF/LoF defects. The response to 4-AP corroborates existing evidence that KCNA2-disorders could benefit from variant-tailored therapeutic approaches, based on functional studies.
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Miterko LN, Lin T, Zhou J, van der Heijden ME, Beckinghausen J, White JJ, Sillitoe RV. Neuromodulation of the cerebellum rescues movement in a mouse model of ataxia. Nat Commun 2021; 12:1295. [PMID: 33637754 PMCID: PMC7910465 DOI: 10.1038/s41467-021-21417-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 01/27/2021] [Indexed: 02/07/2023] Open
Abstract
Deep brain stimulation (DBS) relieves motor dysfunction in Parkinson's disease, and other movement disorders. Here, we demonstrate the potential benefits of DBS in a model of ataxia by targeting the cerebellum, a major motor center in the brain. We use the Car8 mouse model of hereditary ataxia to test the potential of using cerebellar nuclei DBS plus physical activity to restore movement. While low-frequency cerebellar DBS alone improves Car8 mobility and muscle function, adding skilled exercise to the treatment regimen additionally rescues limb coordination and stepping. Importantly, the gains persist in the absence of further stimulation. Because DBS promotes the most dramatic improvements in mice with early-stage ataxia, we postulated that cerebellar circuit function affects stimulation efficacy. Indeed, genetically eliminating Purkinje cell neurotransmission blocked the ability of DBS to reduce ataxia. These findings may be valuable in devising future DBS strategies.
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Affiliation(s)
- Lauren N. Miterko
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XProgram in Developmental Biology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA
| | - Tao Lin
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA
| | - Joy Zhou
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Neuroscience, Baylor College of Medicine, Houston, TX USA
| | - Meike E. van der Heijden
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA
| | - Jaclyn Beckinghausen
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Neuroscience, Baylor College of Medicine, Houston, TX USA
| | - Joshua J. White
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Neuroscience, Baylor College of Medicine, Houston, TX USA
| | - Roy V. Sillitoe
- grid.39382.330000 0001 2160 926XDepartment of Pathology and Immunology, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XProgram in Developmental Biology, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Jan and Dan Duncan Neurological Research Institute of Texas Children’s Hospital, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Neuroscience, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XDevelopment, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX USA
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22
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Nam YW, Cui M, Orfali R, Viegas A, Nguyen M, Mohammed EHM, Zoghebi KA, Rahighi S, Parang K, Zhang M. Hydrophobic interactions between the HA helix and S4-S5 linker modulate apparent Ca 2+ sensitivity of SK2 channels. Acta Physiol (Oxf) 2021; 231:e13552. [PMID: 32865319 PMCID: PMC7736289 DOI: 10.1111/apha.13552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/09/2020] [Accepted: 08/20/2020] [Indexed: 12/11/2022]
Abstract
AIM Small-conductance Ca2+ -activated potassium (SK) channels are activated exclusively by increases in intracellular Ca2+ that binds to calmodulin constitutively associated with the channel. Wild-type SK2 channels are activated by Ca2+ with an EC50 value of ~0.3 μmol/L. Here, we investigate hydrophobic interactions between the HA helix and the S4-S5 linker as a major determinant of channel apparent Ca2+ sensitivity. METHODS Site-directed mutagenesis, electrophysiological recordings and molecular dynamic (MD) simulations were utilized. RESULTS Mutations that decrease hydrophobicity at the HA-S4-S5 interface lead to Ca2+ hyposensitivity of SK2 channels. Mutations that increase hydrophobicity result in hypersensitivity to Ca2+ . The Ca2+ hypersensitivity of the V407F mutant relies on the interaction of the cognate phenylalanine with the S4-S5 linker in the SK2 channel. Replacing the S4-S5 linker of the SK2 channel with the S4-S5 linker of the SK4 channel results in loss of the hypersensitivity caused by V407F. This difference between the S4-S5 linkers of SK2 and SK4 channels can be partially attributed to I295 equivalent to a valine in the SK4 channel. A N293A mutation in the S4-S5 linker also increases hydrophobicity at the HA-S4-S5 interface and elevates the channel apparent Ca2+ sensitivity. The double N293A/V407F mutations generate a highly Ca2+ sensitive channel, with an EC50 of 0.02 μmol/L. The MD simulations of this double-mutant channel revealed a larger channel cytoplasmic gate. CONCLUSION The electrophysiological data and MD simulations collectively suggest a crucial role of the interactions between the HA helix and S4-S5 linker in the apparent Ca2+ sensitivity of SK2 channels.
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Affiliation(s)
- Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, MA, USA
| | - Razan Orfali
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Adam Viegas
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Misa Nguyen
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Eman H M Mohammed
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Khalid A Zoghebi
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Simin Rahighi
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Keykavous Parang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, USA
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In vivo analysis of the spontaneous firing of cerebellar Purkinje cells in awake transgenic mice that model spinocerebellar ataxia type 2. Cell Calcium 2020; 93:102319. [PMID: 33248384 DOI: 10.1016/j.ceca.2020.102319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/12/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022]
Abstract
Cerebellar Purkinje cells (PCs) fire spontaneously in a tonic mode, although the precision of this pacemaking activity is disturbed in many abnormal conditions involving cerebellar atrophy, such as many spinocerebellar ataxias (SCAs). In our previous studies we used the single-unit extracellular recording method to analyze spontaneous PC firing in vivo in the anesthetized SCA2-58Q transgenic mice. We realized that PCs from aging SCA2-58Q mice fire much less regularly compared to PCs from their wild type (WT) littermates and this abnormal activity can be reversed with an intraperitoneal (i. p.) injection of SK channel-positive modulator chlorzoxazone (CHZ). Here we used the same single-unit extracellular recording method to analyze the spontaneous firing in vivo in awake SCA2-58Q transgenic mice. For this purpose, we used the Mobile HomeCage (Neurotar, Finland) floating platform to immobilize the experimental animal's head during the recording sessions. We discovered that generally PCs from awake animals fired much more frequently and much less regularly than previously observed PCs from anesthetized animals. In vivo recordings from awake SCA2/WT mice revealed that complex spikes, which are generated by PCs in reply to the excitation coming by climbing fibers, as well as simple spikes, were much less frequent in SCA2 mice compared to their WT littermates. To test the effect of the SK channel positive modulation on the PCs firing activity in awake SCA2 mice and also the effect on their motor coordination, we started the CHZ trial in these mice. We discovered that the long-term i. p. injections of CHZ did not affect the spike generation in SCA2-58Q mice, however, they did recover the precision of this spontaneous pacemaking activity. Furthermore, we also showed that treatment with CHZ alleviated the age-dependent motor impairment in SCA2-58Q mice. We propose that the lack of precision in PC spike generation might be a key cause for the progression of ataxic symptoms in different SCAs and that the activation of calcium-activated potassium channels, including SK channels, can be used as a potential way to treat SCAs on the physiological level of the disease.
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24
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De Giglio L, Cortese F, Pennisi EM. Aminopiridines in the treatment of multiple sclerosis and other neurological disorders. Neurodegener Dis Manag 2020; 10:409-423. [PMID: 33054615 DOI: 10.2217/nmt-2020-0018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Symptomatic treatment has a great relevance for the management of patients with neurologic diseases, since it reduces disease burden and improves quality of life. Aminopyridines (APs) are a group of potassium (K+) channel blocking agents that exert their activity both at central nervous system level and on neuromuscular junction. This review describes the use of APs for the symptomatic treatment of neurological conditions. We will describe trials leading to the approval of the extended-release 4-aminopyridine for MS and evidence in support of the use in other neurological diseases.
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Affiliation(s)
- Laura De Giglio
- Department of Medicine, San Filippo Neri Hospital, Neurology Unit, Rome, Italy
| | - Francesca Cortese
- Department of Medicine, San Filippo Neri Hospital, Neurology Unit, Rome, Italy
| | - Elena Maria Pennisi
- Department of Medicine, San Filippo Neri Hospital, Neurology Unit, Rome, Italy
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25
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Cook AA, Fields E, Watt AJ. Losing the Beat: Contribution of Purkinje Cell Firing Dysfunction to Disease, and Its Reversal. Neuroscience 2020; 462:247-261. [PMID: 32554108 DOI: 10.1016/j.neuroscience.2020.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023]
Abstract
The cerebellum is a brain structure that is highly interconnected with other brain regions. There are many contributing factors to cerebellar-related brain disease, such as altered afferent input, local connectivity, and/or cerebellar output. Purkinje cells (PC) are the principle cells of the cerebellar cortex, and fire intrinsically; that is, they fire spontaneous action potentials at high frequencies. This review paper focuses on PC intrinsic firing activity, which is altered in multiple neurological diseases, including ataxia, Huntington Disease (HD) and autism spectrum disorder (ASD). Notably, there are several cases where interventions that restore or rescue PC intrinsic activity also improve impaired behavior in these mouse models of disease. These findings suggest that rescuing PC firing deficits themselves may be sufficient to improve impairment in cerebellar-related behavior in disease. We propose that restoring PC intrinsic firing represents a good target for drug development that might be of therapeutic use for several disorders.
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Affiliation(s)
- Anna A Cook
- Department of Biology, McGill University, Montreal, Canada
| | - Eviatar Fields
- Department of Biology, McGill University, Montreal, Canada; Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, Canada.
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26
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Egorova PA, Gavrilova AV, Bezprozvanny IB. Ataxic Symptoms in Huntington's Disease Transgenic Mouse Model Are Alleviated by Chlorzoxazone. Front Neurosci 2020; 14:279. [PMID: 32317916 PMCID: PMC7147686 DOI: 10.3389/fnins.2020.00279] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 03/11/2020] [Indexed: 12/11/2022] Open
Abstract
Huntington’s disease (HD) is a hereditary neurodegenerative disease caused by a polyglutamine expansion in the huntingtin protein, Striatum atrophy in HD leads to a progressive disturbance of psychiatric, motor, and cognitive function. Recent studies of HD patients revealed that the degeneration of cerebellum is also observed independently from the striatal atrophy during early HD stage and may contribute to the motor impairment and ataxia observed in HD. Cerebellar Purkinje cells (PCs) are responsible for the proper cerebellar pathways functioning and motor control. Recent studies on mouse models of HD have shown that the abnormality of the biochemical functions of PCs are observed in HD, suggesting the contribution of PC dysfunction and death to the impaired movement coordination observed in HD. To investigate ataxic symptoms in HD we performed a series of experiments with the yeast artificial chromosome transgenic mouse model of HD (YAC128). Using extracellular single-unit recording method we found that the portion of the cerebellar PCs with bursting and irregular patterns of spontaneous activity drastically rises in aged YAC128 HD mice when compared with wild type littermates. Previous studies demonstrated that SK channels are responsible for the cerebellar PC pacemaker activity and that positive modulation of SK channel activity exerted beneficial effects in different ataxic mouse models. Here we studied effects of the SK channels modulator chlorzoxazone (CHZ) on the motor behavior of YAC128 HD mice and also on the electrophysiological activity and neuroanatomy of the cerebellar PCs from these mice. We determined that the long-term intraperitoneal injections of CHZ alleviated the progressive impairment in the firing pattern of YAC128 PCs. We also demonstrated that treatment with CHZ rescued age-dependent motor incoordination and improved the cerebellar morphology in YAC128 mice. We propose that abnormal changes in the PC firing patterns might be a one of the possible causes of ataxic symptoms in HD and in other polyglutamine disorders and that the pharmacological activation of SK channels may serve as a potential way to improve the activity of cerebellar PCs and relieve the ataxic phenotype in HD patients.
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Affiliation(s)
- Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Aleksandra V Gavrilova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.,Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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27
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Kovermann P, Untiet V, Kolobkova Y, Engels M, Baader S, Schilling K, Fahlke C. Increased glutamate transporter-associated anion currents cause glial apoptosis in episodic ataxia 6. Brain Commun 2020; 2:fcaa022. [PMID: 32954283 PMCID: PMC7425361 DOI: 10.1093/braincomms/fcaa022] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/24/2020] [Accepted: 02/02/2020] [Indexed: 01/08/2023] Open
Abstract
Episodic ataxia type 6 is an inherited neurological condition characterized by combined ataxia and epilepsy. A severe form of this disease with episodes combining ataxia, epilepsy and hemiplegia was recently associated with a proline to arginine substitution at position 290 of the excitatory amino acid transporter 1 in a heterozygous patient. The excitatory amino acid transporter 1 is the predominant glial glutamate transporter in the cerebellum. However, this glutamate transporter also functions as an anion channel and earlier work in heterologous expression systems demonstrated that the mutation impairs the glutamate transport rate, while increasing channel activity. To understand how these changes cause ataxia, we developed a constitutive transgenic mouse model. Transgenic mice display epilepsy, ataxia and cerebellar atrophy and, thus, closely resemble the human disease. We observed increased glutamate-activated chloride efflux in Bergmann glia that triggers the apoptosis of these cells during infancy. The loss of Bergmann glia results in reduced glutamate uptake and impaired neural network formation in the cerebellar cortex. This study shows how gain-of-function of glutamate transporter-associated anion channels causes ataxia through modifying cerebellar development.
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Affiliation(s)
- Peter Kovermann
- Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Verena Untiet
- Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Yulia Kolobkova
- Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Miriam Engels
- Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Stephan Baader
- Anatomisches Institut, Anatomie und Zellbiologie, Rheinische Friedrich-Wilhelm Universität Bonn, 53115 Bonn, Germany
| | - Karl Schilling
- Anatomisches Institut, Anatomie und Zellbiologie, Rheinische Friedrich-Wilhelm Universität Bonn, 53115 Bonn, Germany
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52428 Jülich, Germany
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28
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The neurological update: therapies for cerebellar ataxias in 2020. J Neurol 2020; 267:1211-1220. [DOI: 10.1007/s00415-020-09717-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/12/2020] [Accepted: 01/18/2020] [Indexed: 12/28/2022]
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Abstract
The cerebellum works as a network hub for optimizing eye movements through its mutual connections with the brainstem and beyond. Here, we review three key areas in the cerebellum that are related to the control of eye movements: (1) the flocculus/paraflocculus (tonsil) complex, primarily for high-frequency, transient vestibular responses, and also for smooth pursuit maintenance and steady gaze holding; (2) the nodulus/ventral uvula, primarily for low-frequency, sustained vestibular responses; and (3) the dorsal vermis/posterior fastigial nucleus, primarily for the accuracy of saccades. Although there is no absolute compartmentalization of function within the three major ocular motor areas in the cerebellum, the structural-functional approach provides a framework for assessing ocular motor performance in patients with disease that involves the cerebellum or the brainstem.
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30
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Recent Advances in the Treatment of Cerebellar Disorders. Brain Sci 2019; 10:brainsci10010011. [PMID: 31878024 PMCID: PMC7017280 DOI: 10.3390/brainsci10010011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/13/2019] [Accepted: 12/20/2019] [Indexed: 12/19/2022] Open
Abstract
Various etiopathologies affect the cerebellum, resulting in the development of cerebellar ataxias (CAs), a heterogeneous group of disorders characterized clinically by movement incoordination, affective dysregulation, and cognitive dysmetria. Recent progress in clinical and basic research has opened the door of the ‘‘era of therapy” of CAs. The therapeutic rationale of cerebellar diseases takes into account the capacity of the cerebellum to compensate for pathology and restoration, which is collectively termed cerebellar reserve. In general, treatments of CAs are classified into two categories: cause-cure treatments, aimed at arresting disease progression, and neuromodulation therapies, aimed at potentiating cerebellar reserve. Both forms of therapies should be introduced as soon as possible, at a time where cerebellar reserve is still preserved. Clinical studies have established evidence-based cause-cure treatments for metabolic and immune-mediated CAs. Elaborate protocols of rehabilitation and non-invasive cerebellar stimulation facilitate cerebellar reserve, leading to recovery in the case of controllable pathologies (metabolic and immune-mediated CAs) and delay of disease progression in the case of uncontrollable pathologies (degenerative CAs). Furthermore, recent advances in molecular biology have encouraged the development of new forms of therapies: the molecular targeting therapy, which manipulates impaired RNA or proteins, and the neurotransplantation therapy, which delays cell degeneration and facilitates compensatory functions. The present review focuses on the therapeutic rationales of these recently developed therapeutic modalities, highlighting the underlying pathogenesis.
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31
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Kuo SH, Louis ED, Faust PL, Handforth A, Chang SY, Avlar B, Lang EJ, Pan MK, Miterko LN, Brown AM, Sillitoe RV, Anderson CJ, Pulst SM, Gallagher MJ, Lyman KA, Chetkovich DM, Clark LN, Tio M, Tan EK, Elble RJ. Current Opinions and Consensus for Studying Tremor in Animal Models. CEREBELLUM (LONDON, ENGLAND) 2019; 18:1036-1063. [PMID: 31124049 PMCID: PMC6872927 DOI: 10.1007/s12311-019-01037-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tremor is the most common movement disorder; however, we are just beginning to understand the brain circuitry that generates tremor. Various neuroimaging, neuropathological, and physiological studies in human tremor disorders have been performed to further our knowledge of tremor. But, the causal relationship between these observations and tremor is usually difficult to establish and detailed mechanisms are not sufficiently studied. To overcome these obstacles, animal models can provide an important means to look into human tremor disorders. In this manuscript, we will discuss the use of different species of animals (mice, rats, fruit flies, pigs, and monkeys) to model human tremor disorders. Several ways to manipulate the brain circuitry and physiology in these animal models (pharmacology, genetics, and lesioning) will also be discussed. Finally, we will discuss how these animal models can help us to gain knowledge of the pathophysiology of human tremor disorders, which could serve as a platform towards developing novel therapies for tremor.
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Affiliation(s)
- Sheng-Han Kuo
- Department of Neurology, Columbia University, 650 West 168th Street, Room 305, New York, NY, 10032, USA.
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, 800 Howard Avenue, Ste Lower Level, New Haven, CT, 06519, USA.
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA.
- Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Adrian Handforth
- Neurology Service, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Su-Youne Chang
- Department of Neurologic Surgery and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Billur Avlar
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Eric J Lang
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Ming-Kai Pan
- Department of Medical Research and Neurology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Lauren N Miterko
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA
| | - Amanda M Brown
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Collin J Anderson
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | | | - Kyle A Lyman
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Lorraine N Clark
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Murni Tio
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL, USA
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32
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Self-motion perception is sensitized in vestibular migraine: pathophysiologic and clinical implications. Sci Rep 2019; 9:14323. [PMID: 31586151 PMCID: PMC6778132 DOI: 10.1038/s41598-019-50803-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 09/16/2019] [Indexed: 12/30/2022] Open
Abstract
Vestibular migraine (VM) is the most common cause of spontaneous vertigo but remains poorly understood. We investigated the hypothesis that central vestibular pathways are sensitized in VM by measuring self-motion perceptual thresholds in patients and control subjects and by characterizing the vestibulo-ocular reflex (VOR) and vestibular and headache symptom severity. VM patients were abnormally sensitive to roll tilt, which co-modulates semicircular canal and otolith organ activity, but not to motions that activate the canals or otolith organs in isolation, implying sensitization of canal-otolith integration. When tilt thresholds were considered together with vestibular symptom severity or VOR dynamics, VM patients segregated into two clusters. Thresholds in one cluster correlated positively with symptoms and with the VOR time constant; thresholds in the second cluster were uniformly low and independent of symptoms and the time constant. The VM threshold abnormality showed a frequency-dependence that paralleled the brain stem velocity storage mechanism. These results support a pathogenic model where vestibular symptoms emanate from the vestibular nuclei, which are sensitized by migraine-related brainstem regions and simultaneously suppressed by inhibitory feedback from the cerebellar nodulus and uvula, the site of canal-otolith integration. This conceptual framework elucidates VM pathophysiology and could potentially facilitate its diagnosis and treatment.
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Egorova PA, Bezprozvanny IB. Molecular Mechanisms and Therapeutics for Spinocerebellar Ataxia Type 2. Neurotherapeutics 2019; 16:1050-1073. [PMID: 31435879 PMCID: PMC6985344 DOI: 10.1007/s13311-019-00777-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The effective therapeutic treatment and the disease-modifying therapy for spinocerebellar ataxia type 2 (SCA2) (a progressive hereditary disease caused by an expansion of polyglutamine in the ataxin-2 protein) is not available yet. At present, only symptomatic treatment and methods of palliative care are prescribed to the patients. Many attempts were made to study the physiological, molecular, and biochemical changes in SCA2 patients and in a variety of the model systems to find new therapeutic targets for SCA2 treatment. A better understanding of the uncovered molecular mechanisms of the disease allowed the scientific community to develop strategies of potential therapy and helped to create some promising therapeutic approaches for SCA2 treatment. Recent progress in this field will be discussed in this review article.
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Affiliation(s)
- Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, 195251, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, 195251, Russia.
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, ND12.200, Dallas, Texas, 75390, USA.
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Hsiao CT, Fu SJ, Liu YT, Lu YH, Zhong CY, Tang CY, Soong BW, Jeng CJ. Novel SCA19/22-associated KCND3 mutations disrupt human K V 4.3 protein biosynthesis and channel gating. Hum Mutat 2019; 40:2088-2107. [PMID: 31293010 DOI: 10.1002/humu.23865] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 07/05/2019] [Accepted: 07/07/2019] [Indexed: 11/07/2022]
Abstract
Mutations in the human voltage-gated K+ channel subunit KV 4.3-encoding KCND3 gene have been associated with the autosomal dominant neurodegenerative disorder spinocerebellar ataxia types 19 and 22 (SCA19/22). The precise pathophysiology underlying the dominant inheritance pattern of SCA19/22 remains elusive. Using cerebellar ataxia-specific targeted next-generation sequencing technology, we identified two novel KCND3 mutations, c.950 G>A (p.C317Y) and c.1123 C>T (p.P375S) from a cohort with inherited cerebellar ataxias in Taiwan. The patients manifested notable phenotypic heterogeneity that includes cognitive impairment. We employed in vitro heterologous expression systems to inspect the biophysical and biochemical properties of human KV 4.3 harboring the two novel mutations, as well as two previously reported but uncharacterized disease-related mutations, c.1013 T>A (p.V338E) and c.1130 C>T (p.T377M). Electrophysiological analyses revealed that all of these SCA19/22-associated KV 4.3 mutant channels manifested loss-of-function phenotypes. Protein chemistry and immunofluorescence analyses further demonstrated that these mutants displayed enhanced protein degradation and defective membrane trafficking. By coexpressing KV 4.3 wild-type with the disease-related mutants, we provided direct evidence showing that the mutants instigated anomalous protein biosynthesis and channel gating of KV 4.3. We propose that the dominant inheritance pattern of SCA19/22 may be explained by the dominant-negative effects of the mutants on protein biosynthesis and voltage-dependent gating of KV 4.3 wild-type channel.
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Affiliation(s)
- Cheng-Tsung Hsiao
- Department of Internal Medicine, Taipei Veterans General Hospital Taoyuan Branch, Taoyuan, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ssu-Ju Fu
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yo-Tsen Liu
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Hsiang Lu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ciao-Yu Zhong
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Yung Tang
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Bing-Wen Soong
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan
- Department of Neurology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan
| | - Chung-Jiuan Jeng
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan
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Impact of 4-aminopyridine on vestibulo-ocular reflex performance. J Neurol 2019; 266:93-100. [PMID: 31270663 DOI: 10.1007/s00415-019-09452-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 01/14/2023]
Abstract
Vestibulo-ocular reflexes (VOR) are mediated by frequency-tuned pathways that separately transform the different dynamic and static aspects of head motion/position-related sensory signals into extraocular motor commands. Voltage-dependent potassium conductances such as those formed by Kv1.1 are important for the ability of VOR circuit elements to encode highly transient motion components. Here we describe the impact of the Kv1.1 channel blocker 4-aminopyridine (4-AP) on spontaneous and motion-evoked discharge of superior oblique motoneurons. Spike activity was recorded from the motor nerve in isolated preparations of Xenopus laevis tadpoles. Under static conditions, bath application of 1-10 µM 4-AP increased the spontaneous firing rate and provoked repetitive bursts of spikes. During motion stimulation 4-AP also augmented and delayed the peak firing rate suggesting that this drug affects the magnitude and timing of vestibular-evoked eye movements. The exclusive Kv1.1 expression in thick vestibular afferent fibers in larval Xenopus at this developmental stage suggests that the altered extraocular motor output in the presence of 4-AP mainly derives from a firing rate increase of irregular firing vestibular afferents that propagates along the VOR circuitry. Clinically and pharmacologically, the observed 4-AP-mediated increase of peripheral vestibular input under resting and dynamic conditions can contribute to the observed therapeutic effects of 4-AP in downbeat and upbeat nystagmus as well as episodic ataxia type 2, by an indirect increase of cerebellar Purkinje cell discharge.
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Miterko LN, Sillitoe RV. Climbing Fiber Development Is Impaired in Postnatal Car8 wdl Mice. THE CEREBELLUM 2019; 17:56-61. [PMID: 28940157 DOI: 10.1007/s12311-017-0886-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The cerebellum is critical for an array of motor functions. During postnatal development, the Purkinje cells (PCs) guide afferent topography to establish the final circuit. Perturbing PC morphogenesis or activity during development can result in climbing fiber (CF) multi-innervation or mis-patterning. Structural defects during circuit formation typically have long-term effects on behavior as they contribute to the phenotype of movement disorders such as cerebellar ataxia. The Car8 wdl mouse is one model in which early circuit destruction influences movement. However, although the loss of Car8 leads to the mis-wiring of afferent maps and abnormal PC firing, adult PC morphology is largely intact and there is no neurodegeneration. Here, we sought to uncover how defects in afferent connectivity arise in Car8 wdl mutants to resolve how functional deficits persist in motor diseases with subtle neuropathology. To address this problem, we analyzed CF development during the first 3 weeks of life. By immunolabeling CF terminals with VGLUT2, we found evidence of premature CF synapse elimination and delayed translocation from PC somata at postnatal day (P) 10 in Car8 wdl mice. Surprisingly, by P15, the wiring normalized, suggesting that CAR8 regulates the early but not the late stages of CF development. The data support the hypothesis of a defined sequence of events for cerebellar circuits to establish function.
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Affiliation(s)
- Lauren N Miterko
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA. .,Program in Developmental Biology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA. .,Department of Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA.
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In Vivo Analysis of the Climbing Fiber-Purkinje Cell Circuit in SCA2-58Q Transgenic Mouse Model. THE CEREBELLUM 2019; 17:590-600. [PMID: 29876801 DOI: 10.1007/s12311-018-0951-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cerebellar Purkinje cells (PCs) and cerebellar pathways are primarily affected in many autosomal dominant cerebellar ataxias. PCs generate complex spikes (CS) in vivo when activated by climbing fiber (CF) which rise from the inferior olive. In this study, we investigated the functional state of the CF-PC circuitry in the transgenic mouse model of spinocerebellar ataxia type 2 (SCA2), a polyglutamine neurodegenerative genetic disease. In our experiments, we used an extracellular single-unit recording method to compare the PC activity pattern and the CS shape in age-matched wild-type mice and SCA2-58Q transgenic mice. We discovered no alterations in the CS properties of PCs in aging SCA2 mice. To examine the integrity of the olivocerebellar pathway, we applied harmaline, an alkaloid that acts directly on the inferior olive neurons. The pharmacological stimulation of olivocerebellar circuit by harmaline uncovered disturbances in SCA2-58Q PC activity pattern and in the complex spike shape when compared with age-matched wild-type cells. The abnormalities in the CF-PC circuitry were aggravated with age. We propose that alterations in CF-PC circuitry represent one of potential causes of ataxic symptoms in SCA2 and in other SCAs.
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38
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Payne HL, French RL, Guo CC, Nguyen-Vu TB, Manninen T, Raymond JL. Cerebellar Purkinje cells control eye movements with a rapid rate code that is invariant to spike irregularity. eLife 2019; 8:37102. [PMID: 31050648 PMCID: PMC6499540 DOI: 10.7554/elife.37102] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 04/16/2019] [Indexed: 12/24/2022] Open
Abstract
The rate and temporal pattern of neural spiking each have the potential to influence computation. In the cerebellum, it has been hypothesized that the irregularity of interspike intervals in Purkinje cells affects their ability to transmit information to downstream neurons. Accordingly, during oculomotor behavior in mice and rhesus monkeys, mean irregularity of Purkinje cell spiking varied with mean eye velocity. However, moment-to-moment variations revealed a tight correlation between eye velocity and spike rate, with no additional information conveyed by spike irregularity. Moreover, when spike rate and irregularity were independently controlled using optogenetic stimulation, the eye movements elicited were well-described by a linear population rate code with 3-5 ms temporal precision. Biophysical and random-walk models identified biologically realistic parameter ranges that determine whether spike irregularity influences responses downstream. The results demonstrate cerebellar control of movements through a remarkably rapid rate code, with no evidence for an additional contribution of spike irregularity.
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Affiliation(s)
- Hannah L Payne
- Department of Neurobiology, Stanford University, Stanford, United States
| | - Ranran L French
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, United States
| | - Christine C Guo
- Mental Health Program, QIMR Berghofer Medical Research Institute, Queensland, Australia
| | | | - Tiina Manninen
- Department of Neurobiology, Stanford University, Stanford, United States.,Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Jennifer L Raymond
- Department of Neurobiology, Stanford University, Stanford, United States
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Abstract
Major advances in our understanding of the neurology/pathology, anatomy/physiology, and molecular biology of the cerebellum have opened a new door for cerebellar ataxias (CAs). We have now entered in the ‘era of therapies’. Cures are knocking at the door. We discuss the hot topics in the therapeutic protocols available for CAs, including aminopyridines, noninvasive cerebellar stimulation, anti-oxidant drugs and therapies for immune-mediated cerbellar ataxias (IMCAs), topics emphasized in this issue. The history of the cerebellum is a typical example of the importance of apparently divergent and multi-disciplinary approaches.
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Affiliation(s)
- Hiroshi Mitoma
- Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan
| | - Mario Manto
- Service de Neurologie, CHUCharleroi, Charleroi, Belgium.,Service des Neurosciences, Université de Mons, 7000 Mons, Belgium
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40
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Kalla R, Strupp M. Aminopyridines and Acetyl-DL-leucine: New Therapies in Cerebellar Disorders. Curr Neuropharmacol 2019; 17:7-13. [PMID: 30182858 PMCID: PMC6341500 DOI: 10.2174/1570159x16666180905093535] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/23/2017] [Accepted: 08/30/2018] [Indexed: 12/27/2022] Open
Abstract
Cerebellar ataxia is a frequent and often disabling syndrome severely impairing motor functioning and quality of life. Patients suffer from reduced mobility, and restricted autonomy, experiencing an even lower quality of life than, e.g., stroke survivors. Aminopyridines have been demonstrated viable for the symptomatic treatment of certain forms of cerebellar ataxia. This article will give an outline of the present pharmacotherapy of different cerebellar disorders. As a current key-therapy for the treatment of downbeat nystagmus 4-aminopyridine (4-AP) is suggested for the treatment of downbeat nystagmus (5-10 mg Twice a day [TID]), a frequent type of persisting nystagmus, due to a compromise of the vestibulo-cerebellum. Studies with animals have demonstrated, that a nonselective blockage of voltage-gated potassium channels (mainly Kv1.5) increases Purkinje- cell (PC) excitability. In episodic ataxia type 2 (EA2), which is frequently caused by mutations of the PQ-calcium channel, the efficacy of 4-AP (5-10 mg TID) has been shown in a randomized controlled trial (RCT). 4-AP was well tolerated in the recommended dosages. 4-AP was also effective in elevating symptoms in cerebellar gait ataxia of different etiologies (2 case series). A new treatment option for cerebellar disease is the amino-acid acetyl-DL-leucine, which has significantly improved cerebellar symptoms in three case series. There are on-going randomized controlled trials for cerebellar ataxia (acetyl-DL-leucine vs placebo; ALCAT), cerebellar gait disorders (SR-form of 4-AP vs placebo; FACEG) and EA2 (sustained-release/SR-form of 4-AP vs acetazolamide vs placebo; EAT2TREAT), which will provide new insights into the pharmacological treatment of cerebellar disorders.
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Affiliation(s)
- Roger Kalla
- Department of Neurology, University Hospital Bern, Bern, Switzerland.,Department of Neurology, German Center for Vertigo and Balance Disorders, and Institute for Clinical Neurosciences, University Hospital Munich, Campus Grosshadern, Munich, Germany
| | - Michael Strupp
- Department of Neurology, German Center for Vertigo and Balance Disorders, and Institute for Clinical Neurosciences, University Hospital Munich, Campus Grosshadern, Munich, Germany
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41
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Hernandez O, Pietrajtis K, Mathieu B, Dieudonné S. Optogenetic stimulation of complex spatio-temporal activity patterns by acousto-optic light steering probes cerebellar granular layer integrative properties. Sci Rep 2018; 8:13768. [PMID: 30213968 PMCID: PMC6137064 DOI: 10.1038/s41598-018-32017-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 08/28/2018] [Indexed: 12/11/2022] Open
Abstract
Optogenetics provides tools to control afferent activity in brain microcircuits. However, this requires optical methods that can evoke asynchronous and coordinated activity within neuronal ensembles in a spatio-temporally precise way. Here we describe a light patterning method, which combines MHz acousto-optic beam steering and adjustable low numerical aperture Gaussian beams, to achieve fast 2D targeting in scattering tissue. Using mossy fiber afferents to the cerebellar cortex as a testbed, we demonstrate single fiber optogenetic stimulation with micron-scale lateral resolution, >100 µm depth-penetration and 0.1 ms spiking precision. Protracted spatio-temporal patterns of light delivered by our illumination system evoked sustained asynchronous mossy fiber activity with excellent repeatability. Combining optical and electrical stimulations, we show that the cerebellar granular layer performs nonlinear integration, whereby sustained mossy fiber activity provides a permissive context for the transmission of salient inputs, enriching combinatorial views on mossy fiber pattern separation.
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Affiliation(s)
- Oscar Hernandez
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France
- Wavefront-engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, Paris Descartes University, Sorbonne Paris Cité, 45 rue des Saints-Pères, 75270, Paris Cedex 06, France
- CNC Program, Stanford University, Stanford, California, 94305, USA
| | - Katarzyna Pietrajtis
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France
| | - Benjamin Mathieu
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France
| | - Stéphane Dieudonné
- Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, PSL Université, 46 rue d'Ulm, 75005, Paris, France.
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Pilotto F, Saxena S. Epidemiology of inherited cerebellar ataxias and challenges in clinical research. CLINICAL AND TRANSLATIONAL NEUROSCIENCE 2018. [DOI: 10.1177/2514183x18785258] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Federica Pilotto
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
- Regenerative Neuroscience Cluster, University of Bern, Bern, Switzerland
| | - Smita Saxena
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, Switzerland
- Regenerative Neuroscience Cluster, University of Bern, Bern, Switzerland
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Ady V, Toscano-Márquez B, Nath M, Chang PK, Hui J, Cook A, Charron F, Larivière R, Brais B, McKinney RA, Watt AJ. Altered synaptic and firing properties of cerebellar Purkinje cells in a mouse model of ARSACS. J Physiol 2018; 596:4253-4267. [PMID: 29928778 DOI: 10.1113/jp275902] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/19/2018] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative human disease characterized in part by ataxia and Purkinje cell loss in anterior cerebellar lobules. A knock-out mouse model has been developed that recapitulates several features of ARSACS. Using this ARSACS mouse model, we report changes in synaptic input and intrinsic firing in cerebellar Purkinje cells, as well as in their synaptic output in the deep cerebellar nuclei. Changes in firing are observed in anterior lobules that later exhibit Purkinje cell death, but not in posterior lobules that do not. Our results show that both synaptic and intrinsic alterations in Purkinje cell properties likely contribute to disease manifestation in ARSACS; these findings resemble pathophysiological changes reported in several other ataxias. ABSTRACT Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative disease that includes a pronounced and progressive cerebellar dysfunction. ARSACS is caused by an autosomal recessive loss-of-function mutation in the Sacs gene that encodes the protein sacsin. To better understand the cerebellar pathophysiology in ARSACS, we studied synaptic and firing properties of Purkinje cells from a mouse model of ARSACS, Sacs-/- mice. We found that excitatory synaptic drive was reduced onto Sacs-/- Purkinje cells, and that Purkinje cell firing rate, but not regularity, was reduced at postnatal day (P)40, an age when ataxia symptoms were first reported. Firing rate deficits were limited to anterior lobules that later display Purkinje cell death, and were not observed in posterior lobules where Purkinje cells are not lost. Mild firing deficits were observed as early as P20, prior to the manifestation of motor deficits, suggesting that a critical level of cerebellar dysfunction is required for motor coordination to emerge. Finally, we observed a reduction in Purkinje cell innervation onto target neurons in the deep cerebellar nuclei (DCN) in Sacs-/- mice. Together, these findings suggest that multiple alterations in the cerebellar circuit including Purkinje cell input and output contribute to cerebellar-related disease onset in ARSACS.
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Affiliation(s)
- Visou Ady
- Department of Biology, McGill University, Montréal, Canada
| | | | - Moushumi Nath
- Department of Biology, McGill University, Montréal, Canada
| | - Philip K Chang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Jeanette Hui
- Department of Biology, McGill University, Montréal, Canada
| | - Anna Cook
- Department of Biology, McGill University, Montréal, Canada
| | - François Charron
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Roxanne Larivière
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill University, Montréal, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montréal, Canada
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44
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A V-to-F substitution in SK2 channels causes Ca 2+ hypersensitivity and improves locomotion in a C. elegans ALS model. Sci Rep 2018; 8:10749. [PMID: 30013223 PMCID: PMC6048120 DOI: 10.1038/s41598-018-28783-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/29/2018] [Indexed: 11/09/2022] Open
Abstract
Small-conductance Ca2+-activated K+ (SK) channels mediate medium afterhyperpolarization in the neurons and play a key role in the regulation of neuronal excitability. SK channels are potential drug targets for ataxia and Amyotrophic Lateral Sclerosis (ALS). SK channels are activated exclusively by the Ca2+-bound calmodulin. Previously, we identified an intrinsically disordered fragment that is essential for the mechanical coupling between Ca2+/calmodulin binding and channel opening. Here, we report that substitution of a valine to phenylalanine (V407F) in the intrinsically disordered fragment caused a ~6 fold increase in the Ca2+ sensitivity of SK2-a channels. This substitution resulted in a novel interaction between the ectopic phenylalanine and M411, which stabilized PIP2-interacting residue K405, and subsequently enhanced Ca2+ sensitivity. Also, equivalent valine to phenylalanine substitutions in SK1 or SK3 channels conferred Ca2+ hypersensitivity. An equivalent phenylalanine substitution in the Caenorhabditis elegans (C. elegans) SK2 ortholog kcnl-2 partially rescued locomotion defects in an existing C. elegans ALS model, in which human SOD1G85R is expressed at high levels in neurons, confirming that this phenylalanine substitution impacts channel function in vivo. This work for the first time provides a critical reagent for future studies: an SK channel that is hypersensitive to Ca2+ with increased activity in vivo.
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45
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Prosperini L, Castelli L. Spotlight on postural control in patients with multiple sclerosis. Degener Neurol Neuromuscul Dis 2018; 8:25-34. [PMID: 30050386 PMCID: PMC6053902 DOI: 10.2147/dnnd.s135755] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Multiple sclerosis (MS) is a disease that heavily affects postural control, predisposing patients to accidental falls and fall-related injuries, with a relevant burden on their families, health care systems and themselves. Clinical scales aimed to assess balance are easy to administer in daily clinical setting, but suffer from several limitations including their variable execution, subjective judgment in the scoring system, poor performance in identifying patients at higher risk of falls, and statistical concerns mainly related to distribution of their scores. Today we are able to objectively and reliably assess postural control not only with laboratory-grade standard force platform, but also with low-cost systems based on commercial devices that provide acceptable comparability to gold-standard equipment. The sensitivity of measurements derived from force platforms is such that we can detect balance abnormalities even in minimally impaired patients and predict the risk of future accidental falls accurately. By manipulating sensory inputs (dynamic posturography) or by adding a concurrent cognitive task (dual-task paradigm) to the standard postural assessment, we can unmask postural control deficit even in patients at first demyelinating event or in those with a radiologic isolated syndrome. Studies on neuroanatomical correlates support the multifactorial etiology of postural control deficit in MS, with the association with balance impairment being correlated with cerebellum, spinal cord, and highly ordered processing network according to different studies. Postural control deficit can be managed by means of rehabilitation, which is the most important way to improve balance in patients with MS, but there are also suggestions of a beneficial effect of some pharmacologic interventions. On the other hand, it would be useful to pay attention to some drugs that are currently used to manage other symptoms in daily clinical setting because they can further impair postural controls of patients with MS.
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Affiliation(s)
- Luca Prosperini
- Department of Neurosciences, San Camillo-Forlanini Hospital, Rome, Italy,
| | - Letizia Castelli
- Department of Neurology and Psychiatry, Sapienza University, Rome, Italy
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Bushart DD, Shakkottai VG. Ion channel dysfunction in cerebellar ataxia. Neurosci Lett 2018; 688:41-48. [PMID: 29421541 DOI: 10.1016/j.neulet.2018.02.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/02/2018] [Indexed: 12/31/2022]
Abstract
Cerebellar ataxias constitute a heterogeneous group of disorders that result in impaired speech, uncoordinated limb movements, and impaired balance, often ultimately resulting in wheelchair confinement. Motor dysfunction in ataxia can be attributed to dysfunction and degeneration of neurons in the cerebellum and its associated pathways. Recent work has suggested the importance of cerebellar neuronal dysfunction resulting from mutations in specific ion-channels that regulate membrane excitability in the pathogenesis of cerebellar ataxia in humans. Importantly, even in ataxias not directly due to ion-channel mutations, transcriptional changes resulting in ion-channel dysfunction are tied to motor dysfunction and degeneration in models of disease. In this review, we describe the role that ion-channel dysfunction plays in a variety of cerebellar ataxias, and postulate that a potential therapeutic strategy that targets specific ion-channels exists for cerebellar ataxia.
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Affiliation(s)
- David D Bushart
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor MI, USA
| | - Vikram G Shakkottai
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor MI, USA; Department of Neurology, University of Michigan, 4009 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI, 48109, USA.
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Structural insights into the potency of SK channel positive modulators. Sci Rep 2017; 7:17178. [PMID: 29214998 PMCID: PMC5719431 DOI: 10.1038/s41598-017-16607-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/15/2017] [Indexed: 12/26/2022] Open
Abstract
Small-conductance Ca2+-activated K+ (SK) channels play essential roles in the regulation of cellular excitability and have been implicated in neurological and cardiovascular diseases through both animal model studies and human genetic association studies. Over the past two decades, positive modulators of SK channels such as NS309 and 1-EBIO have been developed. Our previous structural studies have identified the binding pocket of 1-EBIO and NS309 that is located at the interface between the channel and calmodulin. In this study, we took advantage of four compounds with potencies varying over three orders of magnitude, including 1-EBIO, NS309, SKS-11 (6-bromo-5-methyl-1H-indole-2,3-dione-3-oxime) and SKS-14 (7-fluoro-3-(hydroxyimino)indolin-2-one). A combination of x-ray crystallographic, computational and electrophysiological approaches was utilized to investigate the interactions between the positive modulators and their binding pocket. A strong trend exists between the interaction energy of the compounds within their binding site calculated from the crystal structures, and the potency of these compounds in potentiating the SK2 channel current determined by electrophysiological recordings. Our results further reveal that the difference in potency of the positive modulators in potentiating SK2 channel activity may be attributed primarily to specific electrostatic interactions between the modulators and their binding pocket.
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Shakkottai VG, Batla A, Bhatia K, Dauer WT, Dresel C, Niethammer M, Eidelberg D, Raike RS, Smith Y, Jinnah HA, Hess EJ, Meunier S, Hallett M, Fremont R, Khodakhah K, LeDoux MS, Popa T, Gallea C, Lehericy S, Bostan AC, Strick PL. Current Opinions and Areas of Consensus on the Role of the Cerebellum in Dystonia. THE CEREBELLUM 2017; 16:577-594. [PMID: 27734238 DOI: 10.1007/s12311-016-0825-6] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A role for the cerebellum in causing ataxia, a disorder characterized by uncoordinated movement, is widely accepted. Recent work has suggested that alterations in activity, connectivity, and structure of the cerebellum are also associated with dystonia, a neurological disorder characterized by abnormal and sustained muscle contractions often leading to abnormal maintained postures. In this manuscript, the authors discuss their views on how the cerebellum may play a role in dystonia. The following topics are discussed: The relationships between neuronal/network dysfunctions and motor abnormalities in rodent models of dystonia. Data about brain structure, cerebellar metabolism, cerebellar connections, and noninvasive cerebellar stimulation that support (or not) a role for the cerebellum in human dystonia. Connections between the cerebellum and motor cortical and sub-cortical structures that could support a role for the cerebellum in dystonia. Overall points of consensus include: Neuronal dysfunction originating in the cerebellum can drive dystonic movements in rodent model systems. Imaging and neurophysiological studies in humans suggest that the cerebellum plays a role in the pathophysiology of dystonia, but do not provide conclusive evidence that the cerebellum is the primary or sole neuroanatomical site of origin.
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Affiliation(s)
- Vikram G Shakkottai
- Department of Neurology, University of Michigan, Room 4009, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA. .,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| | - Amit Batla
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, London, UK
| | - Kailash Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, London, UK
| | - William T Dauer
- Department of Neurology, University of Michigan, Room 4009, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christian Dresel
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Martin Niethammer
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - David Eidelberg
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Robert S Raike
- Global Research Organization, Medtronic Inc. Neuromodulation, Minneapolis, MN, USA
| | - Yoland Smith
- Yerkes National Primate Center and Department of Neurology, Emory University, Atlanta, GA, USA
| | - H A Jinnah
- Department of Neurology, Human Genetics and Pediatrics, Emory University, Atlanta, GA, USA
| | - Ellen J Hess
- Departments of Pharmacology and Neurology, Emory University, Atlanta, GA, USA
| | - Sabine Meunier
- Institut du Cerveau et de la Moelle épinière (ICM), Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR, S 1127, Paris, France.,Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Mark Hallett
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Rachel Fremont
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, USA
| | - Kamran Khodakhah
- Dominick P. Purpura Department of Neuroscience, Department of Psychiatry and Behavioral Sciences, and The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, New York, NY, USA
| | - Mark S LeDoux
- Departments of Neurology, and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Traian Popa
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Cécile Gallea
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France.,Centre de NeuroImagerie de Recherche - CENIR, ICM, F-75013, Paris, France
| | - Stéphane Lehericy
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Andreea C Bostan
- Systems Neuroscience Institute and Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter L Strick
- Systems Neuroscience Institute and Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurobiology, University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA, USA
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Dorgans K, Salvi J, Bertaso F, Bernard L, Lory P, Doussau F, Mezghrani A. Characterization of the dominant inheritance mechanism of Episodic Ataxia type 2. Neurobiol Dis 2017; 106:110-123. [PMID: 28688851 DOI: 10.1016/j.nbd.2017.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 06/30/2017] [Accepted: 07/04/2017] [Indexed: 12/01/2022] Open
Abstract
Episodic Ataxia type 2 (EA2) is an autosomal dominant neuronal disorder linked to mutations in the Cav2.1 subunit of P/Q-type calcium channels. In vitro studies have established that EA2 mutations induce loss of channel activity and that EA2 mutants can exert a dominant negative effect, suppressing normal Cav2.1 activity through protein misfolding and trafficking defects. To date, the role of this mechanism in the disease pathogenesis is unknown because no animal model exists. To address this issue, we have generated a mouse bearing the R1497X nonsense mutation in Cav2.1 (Cav2.1R1497X). Phenotypic analysis of heterozygous Cav2.1R1497X mice revealed ataxia associated with muscle weakness and generalized absence epilepsy. Electrophysiological studies of the cerebellar circuits in heterozygous Cav2.1R1497X mice highlighted severe dysregulations in synaptic transmission of the two major excitatory inputs as well as alteration of the spontaneous activity of Purkinje cells. Moreover, these neuronal dysfunctions were associated with a strong suppression of Cav2.1 channel expression in the cerebellum of heterozygous Cav2.1R1497X mice. Finally, the presence of Cav2.1 in cerebellar lipid raft microdomains was strongly impaired in heterozygous Cav2.1R1497X mice. Altogether, these results reveal a pathogenic mechanism for EA2 based on a dominant negative activity of mutant channels.
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Affiliation(s)
- Kevin Dorgans
- Institut des Neurosciences Cellulaires et Intégratives-INCI CNRS-UPR 3212, 5 rue Blaise Pascal, 67084 Strasbourg, France
| | - Julie Salvi
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U1191, Université de Montpellier, LabEx 'Ion Channel Science and Therapeutics', 141 rue de la Cardonille, 34094 Montpellier, France
| | - Federica Bertaso
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U1191, Université de Montpellier, LabEx 'Ion Channel Science and Therapeutics', 141 rue de la Cardonille, 34094 Montpellier, France
| | - Ludivine Bernard
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U1191, Université de Montpellier, LabEx 'Ion Channel Science and Therapeutics', 141 rue de la Cardonille, 34094 Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U1191, Université de Montpellier, LabEx 'Ion Channel Science and Therapeutics', 141 rue de la Cardonille, 34094 Montpellier, France.
| | - Frederic Doussau
- Institut des Neurosciences Cellulaires et Intégratives-INCI CNRS-UPR 3212, 5 rue Blaise Pascal, 67084 Strasbourg, France
| | - Alexandre Mezghrani
- Institut des Neurosciences de Montpellier, INSERM U1051, Hôpital Saint Eloi - Bâtiment INM, 80 rue Augustin Fliche, 34091 Montpellier, France.
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50
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Hoyer C, Alonso A, Schlotter-Weigel B, Platten M, Fatar M. HIV-Associated Cerebellar Dysfunction and Improvement with Aminopyridine Therapy: A Case Report. Case Rep Neurol 2017. [PMID: 28626409 PMCID: PMC5471757 DOI: 10.1159/000475544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Apart from infectious causes and cerebellar dysfunction associated with acquired immune deficiency syndrome dementia or HIV-associated neurocognitive disorder, cerebellar dysfunction in HIV-positive individuals has been ascribed to granule cell neuronopathy as well as primary cerebellar atrophy without identifiable etiology. We report the case of a patient with progressive cerebellar dysfunction as the primary manifestation of HIV infection. No symptom improvement was seen under combination antiretroviral therapy, which had been established upon diagnosis, but the patient improved rapidly under 4-aminopyridine treatment, which was recommended 1 year later. Our report, adding to the rather small number of reports of HIV-associated cerebellar atrophy and dysfunction as a primary manifestation of HIV infection, draws attention to HIV as a possible differential etiology of a cerebellar syndrome. Further, rapid improvement of symptom severity under 4-aminopyridine treatment warrants further investigation with longer-term follow-up into the effectiveness of this compound in gait disorder associated with HIV infection.
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Affiliation(s)
- Carolin Hoyer
- Department of Neurology, University Medical Centre Mannheim, Mannheim, Germany
| | - Angelika Alonso
- Department of Neurology, University Medical Centre Mannheim, Mannheim, Germany
| | - Beate Schlotter-Weigel
- Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Michael Platten
- Department of Neurology, University Medical Centre Mannheim, Mannheim, Germany
| | - Marc Fatar
- Department of Neurology, University Medical Centre Mannheim, Mannheim, Germany
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