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Urrutia J, Arrizabalaga-Iriondo A, Sanchez-del-Rey A, Martinez-Ibargüen A, Gallego M, Casis O, Revuelta M. Therapeutic role of voltage-gated potassium channels in age-related neurodegenerative diseases. Front Cell Neurosci 2024; 18:1406709. [PMID: 38827782 PMCID: PMC11140135 DOI: 10.3389/fncel.2024.1406709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/02/2024] [Indexed: 06/05/2024] Open
Abstract
Voltage-gated ion channels are essential for membrane potential maintenance, homeostasis, electrical signal production and controlling the Ca2+ flow through the membrane. Among all ion channels, the key regulators of neuronal excitability are the voltage-gated potassium channels (KV), the largest family of K+ channels. Due to the ROS high levels in the aging brain, K+ channels might be affected by oxidative agents and be key in aging and neurodegeneration processes. This review provides new insight about channelopathies in the most studied neurodegenerative disorders, such as Alzheimer Disease, Parkinson's Disease, Huntington Disease or Spinocerebellar Ataxia. The main affected KV channels in these neurodegenerative diseases are the KV1, KV2.1, KV3, KV4 and KV7. Moreover, in order to prevent or repair the development of these neurodegenerative diseases, previous KV channel modulators have been proposed as therapeutic targets.
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Affiliation(s)
- Janire Urrutia
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Ane Arrizabalaga-Iriondo
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Ana Sanchez-del-Rey
- Department of Otorhinolaryngology, Faculty of Medicine, University of the Basque Country, Bilbao, Spain
| | - Agustín Martinez-Ibargüen
- Department of Otorhinolaryngology, Faculty of Medicine, University of the Basque Country, Bilbao, Spain
| | - Mónica Gallego
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Oscar Casis
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain
| | - Miren Revuelta
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Bilbao, Spain
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2
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Gazulla J, Berciano J. Potential Benefit of Channel Activators in Loss-of-Function Primary Potassium Channelopathies Causing Heredoataxia. CEREBELLUM (LONDON, ENGLAND) 2024; 23:833-837. [PMID: 37460907 DOI: 10.1007/s12311-023-01584-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/29/2023] [Indexed: 03/20/2024]
Abstract
Potassium channels (KCN) are transmembrane complexes that regulate the resting membrane potential and the duration of action potentials in cells. The opening of KCN brings about an efflux of K+ ions that induces cell repolarization after depolarization, returns the transmembrane potential to its resting state, and enables for continuous spiking ability. The aim of this work was to assess the role of KCN dysfunction in the pathogenesis of hereditary ataxias and the mechanisms of action of KCN opening agents (KCO). In consequence, a review of the ad hoc medical literature was performed. Among hereditary KCN diseases causing ataxia, mutated Kv3.3, Kv4.3, and Kv1.1 channels provoke spinocerebellar ataxia (SCA) type 13, SCA19/22, and episodic ataxia type 1 (EA1), respectively. The K+ efflux was found to be reduced in experimental models of these diseases, resulting in abnormally prolonged depolarization and incomplete repolarization, thereby interfering with repetitive discharges in the cells. Hence, substances able to promote normal spiking activity in the cerebellum could provide symptomatic benefit. Although drugs used in clinical practice do not activate Kv3.3 or Kv4.3 directly, available KCO probably could ameliorate ataxic symptoms in SCA13 and SCA19/22, as verified with acetazolamide in EA1, and retigabine in a mouse model of hypokalemic periodic paralysis. To summarize, ataxia could possibly be improved by non-specific KCO in SCA13 and SCA19/22. The identification of new specific KCO agents will undoubtedly constitute a promising therapeutic strategy for these diseases.
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Affiliation(s)
- José Gazulla
- Department of Neurology, Hospital Universitario Miguel Servet, Isabel la Católica, 1-3, 50009, Saragossa, Spain.
| | - José Berciano
- Department of Neurology, Hospital Universitario Marqués de Valdecilla (IDIVAL), University of Cantabria, CIBERNED, Avenida de Valdecilla S/N, 39008, Santander, Spain
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3
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Feng H, Clatot J, Kaneko K, Flores-Mendez M, Wengert ER, Koutcher C, Hoddeson E, Lopez E, Lee D, Arias L, Liang Q, Zhang X, Somarowthu A, Covarrubias M, Gunthorpe MJ, Large CH, Akizu N, Goldberg EM. Targeted therapy improves cellular dysfunction, ataxia, and seizure susceptibility in a model of a progressive myoclonus epilepsy. Cell Rep Med 2024; 5:101389. [PMID: 38266642 PMCID: PMC10897515 DOI: 10.1016/j.xcrm.2023.101389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 11/09/2023] [Accepted: 12/20/2023] [Indexed: 01/26/2024]
Abstract
The recurrent variant KCNC1-p.Arg320His causes progressive myoclonus epilepsy (EPM) type 7, defined by progressive myoclonus, epilepsy, and ataxia, and is without effective treatment. KCNC1 encodes the voltage-gated potassium channel subunit Kv3.1, specifically expressed in high-frequency-firing neurons. Variant subunits act via loss of function; hence, EPM7 pathogenesis may involve impaired excitability of Kv3.1-expressing neurons, while enhancing Kv3 activity could represent a viable therapeutic strategy. We generate a mouse model, Kcnc1-p.Arg320His/+, which recapitulates the core features of EPM7, including progressive ataxia and seizure susceptibility. Kv3.1-expressing cerebellar granule cells and neocortical parvalbumin-positive GABAergic interneurons exhibit abnormalities consistent with Kv3 channel dysfunction. A Kv3-specific positive modulator (AUT00206) selectively enhances the firing frequency of Kv3.1-expressing neurons and improves motor function and seizure susceptibility in Kcnc1-Arg320His/+ mice. This work identifies a cellular and circuit basis of dysfunction in EPM7 and demonstrates that Kv3 positive modulators such as AUT00206 have therapeutic potential for the treatment of EPM7.
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Affiliation(s)
- Huijie Feng
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jerome Clatot
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Keisuke Kaneko
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Anesthesiology, Nihon University, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Marco Flores-Mendez
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eric R Wengert
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Carly Koutcher
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emily Hoddeson
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emily Lopez
- The University of Pennsylvania School of Arts and Sciences, Philadelphia, PA, USA
| | - Demetrius Lee
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Leroy Arias
- The University of Pennsylvania School of Arts and Sciences, Philadelphia, PA, USA
| | - Qiansheng Liang
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Xiaohong Zhang
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ala Somarowthu
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Manuel Covarrubias
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Martin J Gunthorpe
- Autifony Therapeutics, Ltd., Stevenage Bioscience Catalyst, Stevenage SG1 2FX, UK
| | - Charles H Large
- Autifony Therapeutics, Ltd., Stevenage Bioscience Catalyst, Stevenage SG1 2FX, UK
| | - Naiara Akizu
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Departments of Pathology & Laboratory Medicine, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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4
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Orfali R, Alwatban AZ, Orfali RS, Lau L, Chea N, Alotaibi AM, Nam YW, Zhang M. Oxidative stress and ion channels in neurodegenerative diseases. Front Physiol 2024; 15:1320086. [PMID: 38348223 PMCID: PMC10859863 DOI: 10.3389/fphys.2024.1320086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/12/2024] [Indexed: 02/15/2024] Open
Abstract
Numerous neurodegenerative diseases result from altered ion channel function and mutations. The intracellular redox status can significantly alter the gating characteristics of ion channels. Abundant neurodegenerative diseases associated with oxidative stress have been documented, including Parkinson's, Alzheimer's, spinocerebellar ataxia, amyotrophic lateral sclerosis, and Huntington's disease. Reactive oxygen and nitrogen species compounds trigger posttranslational alterations that target specific sites within the subunits responsible for channel assembly. These alterations include the adjustment of cysteine residues through redox reactions induced by reactive oxygen species (ROS), nitration, and S-nitrosylation assisted by nitric oxide of tyrosine residues through peroxynitrite. Several ion channels have been directly investigated for their functional responses to oxidizing agents and oxidative stress. This review primarily explores the relationship and potential links between oxidative stress and ion channels in neurodegenerative conditions, such as cerebellar ataxias and Parkinson's disease. The potential correlation between oxidative stress and ion channels could hold promise for developing innovative therapies for common neurodegenerative diseases.
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Affiliation(s)
- Razan Orfali
- Neuroscience Research Department, Research Centre, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Adnan Z. Alwatban
- Neuroscience Research Department, Research Centre, King Fahad Medical City, Riyadh, Saudi Arabia
| | | | - Liz Lau
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, United States
| | - Noble Chea
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, United States
| | - Abdullah M. Alotaibi
- Neuroscience Research Department, Research Centre, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, United States
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, United States
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Kelly JJ, Wen H, Brehm P. Single-cell RNAseq analysis of spinal locomotor circuitry in larval zebrafish. eLife 2023; 12:RP89338. [PMID: 37975797 PMCID: PMC10656102 DOI: 10.7554/elife.89338] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023] Open
Abstract
Identification of the neuronal types that form the specialized circuits controlling distinct behaviors has benefited greatly from the simplicity offered by zebrafish. Electrophysiological studies have shown that in addition to connectivity, understanding of circuitry requires identification of functional specializations among individual circuit components, such as those that regulate levels of transmitter release and neuronal excitability. In this study, we use single-cell RNA sequencing (scRNAseq) to identify the molecular bases for functional distinctions between motoneuron types that are causal to their differential roles in swimming. The primary motoneuron, in particular, expresses high levels of a unique combination of voltage-dependent ion channel types and synaptic proteins termed functional 'cassettes.' The ion channel types are specialized for promoting high-frequency firing of action potentials and augmented transmitter release at the neuromuscular junction, both contributing to greater power generation. Our transcriptional profiling of spinal neurons further assigns expression of this cassette to specific interneuron types also involved in the central circuitry controlling high-speed swimming and escape behaviors. Our analysis highlights the utility of scRNAseq in functional characterization of neuronal circuitry, in addition to providing a gene expression resource for studying cell type diversity.
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Affiliation(s)
- Jimmy J Kelly
- Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
| | - Hua Wen
- Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
| | - Paul Brehm
- Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
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6
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Kelly JJ, Wen H, Brehm P. Single cell RNA-seq analysis of spinal locomotor circuitry in larval zebrafish. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543939. [PMID: 37333232 PMCID: PMC10274715 DOI: 10.1101/2023.06.06.543939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Identification of the neuronal types that form the specialized circuits controlling distinct behaviors has benefited greatly from the simplicity offered by zebrafish. Electrophysiological studies have shown that additional to connectivity, understanding of circuitry requires identification of functional specializations among individual circuit components, such as those that regulate levels of transmitter release and neuronal excitability. In this study we use single cell RNA sequencing (scRNAseq) to identify the molecular bases for functional distinctions between motoneuron types that are causal to their differential roles in swimming. The primary motoneuron (PMn) in particular, expresses high levels of a unique combination of voltage-dependent ion channel types and synaptic proteins termed functional 'cassettes'. The ion channel types are specialized for promoting high frequency firing of action potentials and augmented transmitter release at the neuromuscular junction, both contributing to greater power generation. Our transcriptional profiling of spinal neurons further assigns expression of this cassette to specific interneuron types also involved in the central circuitry controlling high speed swimming and escape behaviors. Our analysis highlights the utility of scRNAseq in functional characterization of neuronal circuitry, in addition to providing a gene expression resource for studying cell type diversity.
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Affiliation(s)
- Jimmy J. Kelly
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Hua Wen
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Paul Brehm
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA
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7
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Li S, Shang D, Du Y, Li Y, Liu R. Epilepsy as the symptom of a spinocerebellar ataxia 13 in a patient presenting with a mutation in the KCNC3 gene. BMC Neurol 2023; 23:246. [PMID: 37365508 DOI: 10.1186/s12883-023-03304-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023] Open
Abstract
BACKGROUND The spinocerebellar ataxias (SCAs) refer to a diverse group of neurodegenerative illnesses that vary clinically and genetically. One of the rare subtypes within this group is SCA13, caused by mutations in the KCNC3 gene. Currently, the prevalence of SCA13 remains uncertain, with only a couple of cases being documented in the Chinese population. This study presented a case study of SCA13, where the patient exhibited clinical symptoms of epilepsy and ataxia. The confirmation of the diagnosis was done through Whole Exome Sequncing. CASE PRESENTATION Since childhood, the seventeen-year-old patient has not been capable of participating in numerous sporting activities and has experienced multiple episodes of unconsciousness within the last two years. The neurological evaluation showed a lack of coordination in the lower limbs. Cerebellar atrophy was detected through brain magnetic resonance imaging (MRI). The patient's gene detection results showed that they exhibit a heterozygous c.1268G > A mutation in the KCNC3 gene located at chr19:50826942. Antiepileptic treatment was promptly administered to the patient, and as a result, her epileptic seizures were resolved quickly. She has since remained free of seizures. After a one-year follow-up, there was no apparent improvement in the patient's health status except seizure free, which may have worsened. CONCLUSION The case study highlights the importance of actively combining cranial MRI with genetic detection in patients with ataxia of no known cause, particularly in children and young patients, to establish an possibly obvious detection. Patients who are young and have ataxia that is first accompanied by extrapyramidal and epilepsy syndromes should be aware of the potential of having SCA13.
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Affiliation(s)
- Shao Li
- Department of Neurology, Luoyang Central Hospital Affiliated to Zhengzhou University, NO. 288, Middle Zhongzhou Road, Xigong Square, Luoyang, 471000, China.
| | - Dandan Shang
- Department of Neurology, Luoyang Central Hospital Affiliated to Zhengzhou University, NO. 288, Middle Zhongzhou Road, Xigong Square, Luoyang, 471000, China
| | - Yanjiao Du
- Department of Neurology, Luoyang Central Hospital Affiliated to Zhengzhou University, NO. 288, Middle Zhongzhou Road, Xigong Square, Luoyang, 471000, China
| | - Yan Li
- Department of Neurology, Luoyang Central Hospital Affiliated to Zhengzhou University, NO. 288, Middle Zhongzhou Road, Xigong Square, Luoyang, 471000, China
| | - Ruihua Liu
- Department of Neurology, Luoyang Central Hospital Affiliated to Zhengzhou University, NO. 288, Middle Zhongzhou Road, Xigong Square, Luoyang, 471000, China
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8
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Kapfhammer JP, Shimobayashi E. Viewpoint: spinocerebellar ataxias as diseases of Purkinje cell dysfunction rather than Purkinje cell loss. Front Mol Neurosci 2023; 16:1182431. [PMID: 37426070 PMCID: PMC10323145 DOI: 10.3389/fnmol.2023.1182431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 07/11/2023] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of hereditary neurodegenerative diseases mostly affecting cerebellar Purkinje cells caused by a wide variety of different mutations. One subtype, SCA14, is caused by mutations of Protein Kinase C gamma (PKCγ), the dominant PKC isoform present in Purkinje cells. Mutations in the pathway in which PKCγ is active, i.e., in the regulation of calcium levels and calcium signaling in Purkinje cells, are the cause of several other variants of SCA. In SCA14, many of the observed mutations in the PKCγ gene were shown to increase the basal activity of PKCγ, raising the possibility that increased activity of PKCγ might be the cause of most forms of SCA14 and might also be involved in the pathogenesis of SCA in related subtypes. In this viewpoint and review article we will discuss the evidence for and against such a major role of PKCγ basal activity and will suggest a hypothesis of how PKCγ activity and the calcium signaling pathway may be involved in the pathogenesis of SCAs despite the different and sometimes opposing effects of mutations affecting these pathways. We will then widen the scope and propose a concept of SCA pathogenesis which is not primarily driven by cell death and loss of Purkinje cells but rather by dysfunction of Purkinje cells which are still present and alive in the cerebellum.
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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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10
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Wang S, Yu Y, Wang X, Deng X, Ma J, Liu Z, Gu W, Sun D. Emerging evidence of genotype–phenotype associations of developmental and epileptic encephalopathy due to KCNC2 mutation: Identification of novel R405G. Front Mol Neurosci 2022; 15:950255. [PMID: 36090251 PMCID: PMC9453199 DOI: 10.3389/fnmol.2022.950255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) have high genetic heterogeneity, and DEE due to the potassium voltage-gated channel subfamily C member 2 (KCNC2) variant remains poorly understood, given the scarcity of related case studies. We report on two unrelated Chinese patients, an 11-year-old boy and a 5-year-old girl, diagnosed with global developmental delay (GDD), intellectual disability (ID), and focal impaired awareness seizure characterized by generalized spike and wave complexes on electroencephalogram (EEG) in the absence of significant brain lesions. Whole-exome sequencing (WES) and electrophysiological analysis were performed to detect genetic variants and evaluate functional changes of the mutant KCNC2, respectively. Importantly, we identified a novel gain-of-function KCNC2 variant, R405G, in both patients. Previously reported variants, V471L, R351K, T437A, and T437N, and novel R405G were found in multiple unrelated patients with DEE, showing consistent genotype–phenotype associations. These findings emphasize that the KCNC2 gene is causative for DEE and facilitates treatment and prognosis in patients with DEE due to KCNC2 mutations.
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Affiliation(s)
- Sumei Wang
- Department of Pediatric Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yejing Yu
- Department of Pediatric Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xu Wang
- Department of Neurology, Changchun Children’s Hospital, Changchun, China
| | - Xiaolong Deng
- Department of Pediatric Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiehui Ma
- Department of Pediatric Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhisheng Liu
- Department of Pediatric Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weiyue Gu
- Chigene (Beijing) Translational Medical Research Center Co. Ltd., Beijing, China
| | - Dan Sun
- Department of Pediatric Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Dan Sun,
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A missense mutation in Kcnc3 causes hippocampal learning deficits in mice. Proc Natl Acad Sci U S A 2022; 119:e2204901119. [PMID: 35881790 PMCID: PMC9351536 DOI: 10.1073/pnas.2204901119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although a wide variety of genetic tools has been developed to study learning and memory, the molecular basis of memory encoding remains incompletely understood. Here, we undertook an unbiased approach to identify novel genes critical for memory encoding. From a large-scale, in vivo mutagenesis screen using contextual fear conditioning, we isolated in mice a mutant, named Clueless, with spatial learning deficits. A causative missense mutation (G434V) was found in the voltage-gated potassium channel, subfamily C member 3 (Kcnc3) gene in a region that encodes a transmembrane voltage sensor. Generation of a Kcnc3G434V CRISPR mutant mouse confirmed this mutation as the cause of the learning defects. While G434V had no effect on transcription, translation, or trafficking of the channel, electrophysiological analysis of the G434V mutant channel revealed a complete loss of voltage-gated conductance, a broadening of the action potential, and decreased neuronal firing. Together, our findings have revealed a role for Kcnc3 in learning and memory.
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Inhibitory Effectiveness in Delayed-Rectifier Potassium Current Caused by Vortioxetine, Known to Be a Novel Antidepressant. Biomedicines 2022; 10:biomedicines10061318. [PMID: 35740340 PMCID: PMC9220334 DOI: 10.3390/biomedicines10061318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 01/27/2023] Open
Abstract
Vortioxetine (VOR) is recognized to exert antidepressant actions. However, whether this drug modifies ionic currents in excitable cells remains unclear. The aim of this study was to explore the electrophysiological effects of VOR and other related compounds in pituitary GH3 cells and in Neuro-2a cells. VOR suppressed the delayed-rectifier K+ current (IK(DR)) in a concentration-, time-, and state-dependent manner. Effective IC50 values needed to inhibit peak and sustained IK(DR) were computed to be 31.2 and 8.5 μM, respectively, while the KD value estimated from minimal binding scheme was 7.9 μM. Cell exposure to serotonin (10 μM) alone failed to alter IK(DR), while fluoxetine (10 μM), a compound structurally similar to VOR, mildly suppressed current amplitude. In continued presence of VOR, neither further addition of propranolol nor risperidone reversed VOR-mediated inhibition of IK(DR). Increasing VOR concentration not only depressed IK(DR) conductance but also shifted toward the hyperpolarized potential. As the VOR concentration was raised, the recovery of IK(DR) block became slowed. The IK(DR) activated by a downsloping ramp was suppressed by its presence. The inhibition of IK(DR) by a train pulse was enhanced during exposure to VOR. In Neuro-2a cells, this drug decreased IK(DR). Overall, inhibitory effects of VOR on ionic currents might constitute another underlying mechanism of its actions.
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13
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Stevens SR, van der Heijden ME, Ogawa Y, Lin T, Sillitoe RV, Rasband MN. Ankyrin-R Links Kv3.3 to the Spectrin Cytoskeleton and Is Required for Purkinje Neuron Survival. J Neurosci 2022; 42:2-15. [PMID: 34785580 PMCID: PMC8741159 DOI: 10.1523/jneurosci.1132-21.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 10/26/2021] [Accepted: 10/31/2021] [Indexed: 11/21/2022] Open
Abstract
Ankyrin scaffolding proteins are critical for membrane domain organization and protein stabilization in many different cell types including neurons. In the cerebellum, Ankyrin-R (AnkR) is highly enriched in Purkinje neurons, granule cells, and in the cerebellar nuclei (CN). Using male and female mice with a floxed allele for Ank1 in combination with Nestin-Cre and Pcp2-Cre mice, we found that ablation of AnkR from Purkinje neurons caused ataxia, regional and progressive neurodegeneration, and altered cerebellar output. We show that AnkR interacts with the cytoskeletal protein β3 spectrin and the potassium channel Kv3.3. Loss of AnkR reduced somatic membrane levels of β3 spectrin and Kv3.3 in Purkinje neurons. Thus, AnkR links Kv3.3 channels to the β3 spectrin-based cytoskeleton. Our results may help explain why mutations in β3 spectrin and Kv3.3 both cause spinocerebellar ataxia.SIGNIFICANCE STATEMENT Ankyrin scaffolding proteins localize and stabilize ion channels in the membrane by linking them to the spectrin-based cytoskeleton. Here, we show that Ankyrin-R (AnkR) links Kv3.3 K+ channels to the β3 spectrin-based cytoskeleton in Purkinje neurons. Loss of AnkR causes Purkinje neuron degeneration, altered cerebellar physiology, and ataxia, which is consistent with mutations in Kv3.3 and β3 spectrin causing spinocerebellar ataxia.
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Affiliation(s)
- Sharon R Stevens
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | | | - Yuki Ogawa
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Tao Lin
- Department Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030
| | - Roy V Sillitoe
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Department Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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14
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Yeap J, Sathyaprakash C, Toombs J, Tulloch J, Scutariu C, Rose J, Burr K, Davies C, Colom-Cadena M, Chandran S, Large CH, Rowan MJM, Gunthorpe MJ, Spires-Jones TL. Reducing voltage-dependent potassium channel Kv3.4 levels ameliorates synapse loss in a mouse model of Alzheimer's disease. Brain Neurosci Adv 2022; 6:23982128221086464. [PMID: 35359460 PMCID: PMC8961358 DOI: 10.1177/23982128221086464] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/18/2022] [Indexed: 11/17/2022] Open
Abstract
Synapse loss is associated with cognitive decline in Alzheimer's disease, and owing to their plastic nature, synapses are an ideal target for therapeutic intervention. Oligomeric amyloid beta around amyloid plaques is known to contribute to synapse loss in mouse models and is associated with synapse loss in human Alzheimer's disease brain tissue, but the mechanisms leading from Aβ to synapse loss remain unclear. Recent data suggest that the fast-activating and -inactivating voltage-gated potassium channel subtype 3.4 (Kv3.4) may play a role in Aβ-mediated neurotoxicity. Here, we tested whether this channel could also be involved in Aβ synaptotoxicity. Using adeno-associated virus and clustered regularly interspaced short palindromic repeats technology, we reduced Kv3.4 expression in neurons of the somatosensory cortex of APP/PS1 mice. These mice express human familial Alzheimer's disease-associated mutations in amyloid precursor protein and presenilin-1 and develop amyloid plaques and plaque-associated synapse loss similar to that observed in Alzheimer's disease brain. We observe that reducing Kv3.4 levels ameliorates dendritic spine loss and changes spine morphology compared to control virus. In support of translational relevance, Kv3.4 protein was observed in human Alzheimer's disease and control brain and is associated with synapses in human induced pluripotent stem cell-derived cortical neurons. We also noted morphological changes in induced pluripotent stem cell neurones challenged with human Alzheimer's disease-derived brain homogenate containing Aβ but, in this in vitro model, total mRNA levels of Kv3.4 were found to be reduced, perhaps as an early compensatory mechanism for Aβ-induced damage. Overall, our results suggest that approaches to reduce Kv3.4 expression and/or function in the Alzheimer's disease brain could be protective against Aβ-induced synaptic alterations.
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Affiliation(s)
- Jie Yeap
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Chaitra Sathyaprakash
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Jamie Toombs
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Jane Tulloch
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Cristina Scutariu
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Jamie Rose
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Karen Burr
- UK Dementia Research Institute and Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Caitlin Davies
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Marti Colom-Cadena
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Siddharthan Chandran
- UK Dementia Research Institute and Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Charles H Large
- Autifony Therapeutics Limited, Stevenage Bioscience Catalyst, Stevenage, UK
| | | | - Martin J Gunthorpe
- Autifony Therapeutics Limited, Stevenage Bioscience Catalyst, Stevenage, UK
| | - Tara L Spires-Jones
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
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15
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Zhang Y, Quraishi IH, McClure H, Williams LA, Cheng Y, Kale S, Dempsey GT, Agrawal S, Gerber DJ, McManus OB, Kaczmarek LK. Suppression of Kv3.3 channels by antisense oligonucleotides reverses biochemical effects and motor impairment in spinocerebellar ataxia type 13 mice. FASEB J 2021; 35:e22053. [PMID: 34820911 DOI: 10.1096/fj.202101356r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/26/2021] [Accepted: 11/08/2021] [Indexed: 11/11/2022]
Abstract
Mutations in KCNC3, the gene that encodes the Kv3.3 voltage dependent potassium channel, cause Spinocerebellar Ataxia type 13 (SCA13), a disease associated with disrupted motor behaviors, progressive cerebellar degeneration, and abnormal auditory processing. The Kv3.3 channel directly binds Hax-1, a cell survival protein. A disease-causing mutation, Kv3.3-G592R, causes overstimulation of Tank Binding Kinase 1 (Tbk1) in the cerebellum, resulting in the degradation of Hax-1 by promoting its trafficking into multivesicular bodies and then to lysosomes. We have now tested the effects of antisense oligonucleotides (ASOs) directed against the Kv3.3 channel on both wild type mice and those bearing the Kv3.3-G592R-encoding mutation. Intracerebroventricular infusion of the Kcnc3-specific ASO suppressed both mRNA and protein levels of the Kv3.3 channel. In wild-type animals, this produced no change in levels of activated Tbk1, Hax-1 or Cd63, a tetraspanin marker for late endosomes/multivesicular bodies. In contrast, in mice homozygous for the Kv3.3-G592R-encoding mutation, the same ASO reduced Tbk1 activation and levels of Cd63, while restoring the expression of Hax-1 in the cerebellum. The motor behavior of the mice was tested using a rotarod assay. Surprisingly, the active ASO had no effects on the motor behavior of wild type mice but restored the behavior of the mutant mice to those of age-matched wild type animals. Our findings indicate that, in mature intact animals, suppression of Kv3.3 expression can reverse the deleterious effects of a SCA13 mutation while having little effect on wild type animals. Thus, targeting Kv3.3 expression may prove a viable therapeutic approach for SCA13.
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Affiliation(s)
- Yalan Zhang
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Imran H Quraishi
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Heather McClure
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | | | | | | | | | | | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA.,Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
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16
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Manickam AH, Ramasamy S. Mutations in the Voltage Dependent Calcium Channel CACNA1A (P/Q type alpha 1A subunit) Causing Neurological Disorders - An Overview. Neurol India 2021; 69:808-816. [PMID: 34507393 DOI: 10.4103/0028-3886.325378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background The voltage-dependent calcium channel α1 subunit (CACNA1A) gene plays a major role in neuronal communication. Mutation in this gene results in altered Ca2+ ion influx that modify the neurotransmitter release resulting in the development of various neurological disorders like hemiplegic migraine with cortical spreading depression, epilepsy, episodic ataxia type 2, and spinocerebellar ataxia type 6. Objective This review aimed in portraying the frequent mutations in CACNA1A gene causing hemiplegic migraine with cortical spreading depression, epilepsy, episodic ataxia type 2 and spinocerebellar ataxia type 6. Methodology A systematic search has been adopted in various databases using the keywords "Calcium channel," "migraine," "epilepsy," "episodic ataxia," and "spinocerebellar ataxia" for writing this review that collectively focuses on mutations in the CACNA1A gene causing the common neurological diseases from 1975 to 2019. Conclusion Every type of mutation has its own signature in gene functioning and understanding them might aid knowing more in disease progression.
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Affiliation(s)
- Agaath Hedina Manickam
- Molecular Genetics and Cancer Biology Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - Sivasamy Ramasamy
- Molecular Genetics and Cancer Biology Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tamil Nadu, India
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17
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Jenkins EPW, Finch A, Gerigk M, Triantis IF, Watts C, Malliaras GG. Electrotherapies for Glioblastoma. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100978. [PMID: 34292672 PMCID: PMC8456216 DOI: 10.1002/advs.202100978] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/20/2021] [Indexed: 05/08/2023]
Abstract
Non-thermal, intermediate frequency (100-500 kHz) electrotherapies present a unique therapeutic strategy to treat malignant neoplasms. Here, pulsed electric fields (PEFs) which induce reversible or irreversible electroporation (IRE) and tumour-treating fields (TTFs) are reviewed highlighting the foundations, advances, and considerations of each method when applied to glioblastoma (GBM). Several biological aspects of GBM that contribute to treatment complexity (heterogeneity, recurrence, resistance, and blood-brain barrier(BBB)) and electrophysiological traits which are suggested to promote glioma progression are described. Particularly, the biological responses at the cellular and molecular level to specific parameters of the electrical stimuli are discussed offering ways to compare these parameters despite the lack of a universally adopted physical description. Reviewing the literature, a disconnect is found between electrotherapy techniques and how they target the biological complexities of GBM that make treatment difficult in the first place. An attempt is made to bridge the interdisciplinary gap by mapping biological characteristics to different methods of electrotherapy, suggesting important future research topics and directions in both understanding and treating GBM. To the authors' knowledge, this is the first paper that attempts an in-tandem assessment of the biological effects of different aspects of intermediate frequency electrotherapy methods, thus offering possible strategies toward GBM treatment.
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Affiliation(s)
- Elise P. W. Jenkins
- Division of Electrical EngineeringDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Alina Finch
- Institute of Cancer and Genomic ScienceUniversity of BirminghamBirminghamB15 2TTUK
| | - Magda Gerigk
- Division of Electrical EngineeringDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Iasonas F. Triantis
- Department of Electrical and Electronic EngineeringCity, University of LondonLondonEC1V 0HBUK
| | - Colin Watts
- Institute of Cancer and Genomic ScienceUniversity of BirminghamBirminghamB15 2TTUK
| | - George G. Malliaras
- Division of Electrical EngineeringDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
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18
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Cerebellar Kv3.3 potassium channels activate TANK-binding kinase 1 to regulate trafficking of the cell survival protein Hax-1. Nat Commun 2021; 12:1731. [PMID: 33741962 PMCID: PMC7979925 DOI: 10.1038/s41467-021-22003-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
Mutations in KCNC3, which encodes the Kv3.3 potassium channel, cause degeneration of the cerebellum, but exactly how the activity of an ion channel is linked to the survival of cerebellar neurons is not understood. Here, we report that Kv3.3 channels bind and stimulate Tank Binding Kinase 1 (TBK1), an enzyme that controls trafficking of membrane proteins into multivesicular bodies, and that this stimulation is greatly increased by a disease-causing Kv3.3 mutation. TBK1 activity is required for the binding of Kv3.3 to its auxiliary subunit Hax-1, which prevents channel inactivation with depolarization. Hax-1 is also an anti-apoptotic protein required for survival of cerebellar neurons. Overactivation of TBK1 by the mutant channel leads to the loss of Hax-1 by its accumulation in multivesicular bodies and lysosomes, and also stimulates exosome release from neurons. This process is coupled to activation of caspases and increased cell death. Our studies indicate that Kv3.3 channels are directly coupled to TBK1-dependent biochemical pathways that determine the trafficking of cellular constituents and neuronal survival. How the activity of the neuronal Kv3.3 voltage-dependent channel is regulated is unclear. Here, the authors show that the known Kv3.3 channel complex with Hax1, which affects spinal cerebellar ataxia, regulates the enzyme Tank Binding Kinase 1, modulating survival of cerebellar neurons.
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19
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Wu XS, Subramanian S, Zhang Y, Shi B, Xia J, Li T, Guo X, El-Hassar L, Szigeti-Buck K, Henao-Mejia J, Flavell RA, Horvath TL, Jonas EA, Kaczmarek LK, Wu LG. Presynaptic Kv3 channels are required for fast and slow endocytosis of synaptic vesicles. Neuron 2021; 109:938-946.e5. [PMID: 33508244 PMCID: PMC7979485 DOI: 10.1016/j.neuron.2021.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/24/2020] [Accepted: 01/07/2021] [Indexed: 01/25/2023]
Abstract
Since their discovery decades ago, the primary physiological and pathological effects of potassium channels have been attributed to their ion conductance, which sets membrane potential and repolarizes action potentials. For example, Kv3 family channels regulate neurotransmitter release by repolarizing action potentials. Here we report a surprising but crucial function independent of potassium conductance: by organizing the F-actin cytoskeleton in mouse nerve terminals, the Kv3.3 protein facilitates slow endocytosis, rapid endocytosis, vesicle mobilization to the readily releasable pool, and recovery of synaptic depression during repetitive firing. A channel mutation that causes spinocerebellar ataxia inhibits endocytosis, vesicle mobilization, and synaptic transmission during repetitive firing by disrupting the ability of the channel to nucleate F-actin. These results unmask novel functions of potassium channels in endocytosis and vesicle mobilization crucial for sustaining synaptic transmission during repetitive firing. Potassium channel mutations that impair these "non-conducting" functions may thus contribute to generation of diverse neurological disorders.
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Affiliation(s)
- Xin-Sheng Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Shobana Subramanian
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Yalan Zhang
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Bo Shi
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA; Biological Sciences Graduate Program, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20740, USA
| | - Jessica Xia
- Division of Biological Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Tiansheng Li
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Xiaoli Guo
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Lynda El-Hassar
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Klara Szigeti-Buck
- Department of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Jorge Henao-Mejia
- Department of Immunobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Richard A Flavell
- Department of Immunobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Department of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Elizabeth A Jonas
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bethesda, MD 20892, USA.
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20
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Wu J, Kaczmarek LK. Modulation of Neuronal Potassium Channels During Auditory Processing. Front Neurosci 2021; 15:596478. [PMID: 33613177 PMCID: PMC7887315 DOI: 10.3389/fnins.2021.596478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/11/2021] [Indexed: 11/16/2022] Open
Abstract
The extraction and localization of an auditory stimulus of interest from among multiple other sounds, as in the ‘cocktail-party’ situation, requires neurons in auditory brainstem nuclei to encode the timing, frequency, and intensity of sounds with high fidelity, and to compare inputs coming from the two cochleae. Accurate localization of sounds requires certain neurons to fire at high rates with high temporal accuracy, a process that depends heavily on their intrinsic electrical properties. Studies have shown that the membrane properties of auditory brainstem neurons, particularly their potassium currents, are not fixed but are modulated in response to changes in the auditory environment. Here, we review work focusing on how such modulation of potassium channels is critical to shaping the firing pattern and accuracy of these neurons. We describe how insights into the role of specific channels have come from human gene mutations that impair localization of sounds in space. We also review how short-term and long-term modulation of these channels maximizes the extraction of auditory information, and how errors in the regulation of these channels contribute to deficits in decoding complex auditory information.
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Affiliation(s)
- Jing Wu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, United States
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, United States
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21
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Hsieh JY, Ulrich BN, Issa FA, Lin MCA, Brown B, Papazian DM. Infant and adult SCA13 mutations differentially affect Purkinje cell excitability, maturation, and viability in vivo. eLife 2020; 9:57358. [PMID: 32644043 PMCID: PMC7386905 DOI: 10.7554/elife.57358] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 07/08/2020] [Indexed: 12/23/2022] Open
Abstract
Mutations in KCNC3, which encodes the Kv3.3 K+ channel, cause spinocerebellar ataxia 13 (SCA13). SCA13 exists in distinct forms with onset in infancy or adulthood. Using zebrafish, we tested the hypothesis that infant- and adult-onset mutations differentially affect the excitability and viability of Purkinje cells in vivo during cerebellar development. An infant-onset mutation dramatically and transiently increased Purkinje cell excitability, stunted process extension, impaired dendritic branching and synaptogenesis, and caused rapid cell death during cerebellar development. Reducing excitability increased early Purkinje cell survival. In contrast, an adult-onset mutation did not significantly alter basal tonic firing in Purkinje cells, but reduced excitability during evoked high frequency spiking. Purkinje cells expressing the adult-onset mutation matured normally and did not degenerate during cerebellar development. Our results suggest that differential changes in the excitability of cerebellar neurons contribute to the distinct ages of onset and timing of cerebellar degeneration in infant- and adult-onset SCA13.
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Affiliation(s)
- Jui-Yi Hsieh
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States.,Interdepartmental PhD Program in Molecular, Cellular, and Integrative Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Brittany N Ulrich
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States.,Interdepartmental PhD Program in Molecular, Cellular, and Integrative Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Fadi A Issa
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Meng-Chin A Lin
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Brandon Brown
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Diane M Papazian
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States.,Interdepartmental PhD Program in Molecular, Cellular, and Integrative Physiology, David Geffen School of Medicine at UCLA, Los Angeles, United States.,Brain Research Institute, UCLA, Los Angeles, United States.,Molecular Biology Institute, UCLA, Los Angeles, United States
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22
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Kessi M, Chen B, Peng J, Tang Y, Olatoutou E, He F, Yang L, Yin F. Intellectual Disability and Potassium Channelopathies: A Systematic Review. Front Genet 2020; 11:614. [PMID: 32655623 PMCID: PMC7324798 DOI: 10.3389/fgene.2020.00614] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/20/2020] [Indexed: 01/15/2023] Open
Abstract
Intellectual disability (ID) manifests prior to adulthood as severe limitations to intellectual function and adaptive behavior. The role of potassium channelopathies in ID is poorly understood. Therefore, we aimed to evaluate the relationship between ID and potassium channelopathies. We hypothesized that potassium channelopathies are strongly associated with ID initiation, and that both gain- and loss-of-function mutations lead to ID. This systematic review explores the burden of potassium channelopathies, possible mechanisms, advancements using animal models, therapies, and existing gaps. The literature search encompassed both PubMed and Embase up to October 2019. A total of 75 articles describing 338 cases were included in this review. Nineteen channelopathies were identified, affecting the following genes: KCNMA1, KCNN3, KCNT1, KCNT2, KCNJ10, KCNJ6, KCNJ11, KCNA2, KCNA4, KCND3, KCNH1, KCNQ2, KCNAB1, KCNQ3, KCNQ5, KCNC1, KCNB1, KCNC3, and KCTD3. Twelve of these genes presented both gain- and loss-of-function properties, three displayed gain-of-function only, three exhibited loss-of-function only, and one had unknown function. How gain- and loss-of-function mutations can both lead to ID remains largely unknown. We identified only a few animal studies that focused on the mechanisms of ID in relation to potassium channelopathies and some of the few available therapeutic options (channel openers or blockers) appear to offer limited efficacy. In conclusion, potassium channelopathies contribute to the initiation of ID in several instances and this review provides a comprehensive overview of which molecular players are involved in some of the most prominent disease phenotypes.
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Affiliation(s)
- Miriam Kessi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China.,Kilimanjaro Christian Medical University College, Moshi, Tanzania.,Mawenzi Regional Referral Hospital, Moshi, Tanzania
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Yulin Tang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Eleonore Olatoutou
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
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23
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Choudhury N, Linley D, Richardson A, Anderson M, Robinson SW, Marra V, Ciampani V, Walter SM, Kopp‐Scheinpflug C, Steinert JR, Forsythe ID. Kv3.1 and Kv3.3 subunits differentially contribute to Kv3 channels and action potential repolarization in principal neurons of the auditory brainstem. J Physiol 2020; 598:2199-2222. [DOI: 10.1113/jp279668] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Affiliation(s)
- Nasreen Choudhury
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Deborah Linley
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Amy Richardson
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Michelle Anderson
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Susan W. Robinson
- Neurotoxicity at the Synaptic Interface MRC Toxicology Unit University of Leicester, UK
| | - Vincenzo Marra
- Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Victoria Ciampani
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Sophie M. Walter
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Conny Kopp‐Scheinpflug
- Division of Neurobiology Department Biology II Ludwig‐Maximilians‐University Munich Großhaderner Strasse 2 Planegg‐Martinsried D‐82152 Germany
| | - Joern R. Steinert
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Ian D. Forsythe
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
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Namikawa K, Dorigo A, Köster RW. Neurological Disease Modelling for Spinocerebellar Ataxia Using Zebrafish. J Exp Neurosci 2019; 13:1179069519880515. [PMID: 31666796 PMCID: PMC6798160 DOI: 10.1177/1179069519880515] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 01/02/2023] Open
Abstract
The cerebellum integrates sensory information and motor actions. Increasing
experimental evidence has revealed that these functions as well as the
cerebellar cytoarchitecture are highly conserved in zebrafish compared with
mammals. However, the potential of zebrafish for modelling human cerebellar
diseases remains to be addressed. Spinocerebellar ataxias (SCAs) represent a
group of genetically inherited cerebellar diseases leading to motor
discoordination that is most often caused by affected cerebellar Purkinje cells
(PCs). Towards modelling SCAs in zebrafish we identified a small-sized
PC-specific regulatory element that was used to develop coexpression vectors
with tunable expression strength. These vectors allow for in vivo imaging of
SCA-affected PCs by high-resolution fluorescence imaging. Next, zebrafish with
SCA type 13 (SCA13) transgene expression were established, revealing that
SCA13-induced cell-autonomous PC degeneration results in eye movement deficits.
Thus, SCA13 zebrafish mimic the neuropathology of an SCA-affected brain as well
as the involved loss of motor control and hence provide a powerful approach to
unravel SCA13-induced cell biological pathogenic and cytotoxic mechanisms.
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Affiliation(s)
- Kazuhiko Namikawa
- Cellular and Molecular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Alessandro Dorigo
- Cellular and Molecular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Reinhard W Köster
- Cellular and Molecular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
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25
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Cameron JM, Maljevic S, Nair U, Aung YH, Cogné B, Bézieau S, Blair E, Isidor B, Zweier C, Reis A, Koenig MK, Maarup T, Sarco D, Afenjar A, Huq AHMM, Kukolich M, Billette de Villemeur T, Nava C, Héron B, Petrou S, Berkovic SF. Encephalopathies with KCNC1 variants: genotype-phenotype-functional correlations. Ann Clin Transl Neurol 2019; 6:1263-1272. [PMID: 31353855 PMCID: PMC6649578 DOI: 10.1002/acn3.50822] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE To analyze clinical phenotypes associated with KCNC1 variants other than the Progressive Myoclonus Epilepsy-causing variant p.Arg320His, determine the electrophysiological functional impact of identified variants and explore genotype-phenotype-physiological correlations. METHODS Ten cases with putative pathogenic variants in KCNC1 were studied. Variants had been identified via whole-exome sequencing or gene panel testing. Clinical phenotypic data were analyzed. To determine functional impact of variants detected in the Kv 3.1 channel encoded by KCNC1, Xenopus laevis oocyte expression system and automated two-electrode voltage clamping were used. RESULTS Six unrelated patients had a Developmental and Epileptic Encephalopathy and a recurrent de novo variant p.Ala421Val (c.1262C > T). Functional analysis of p.Ala421Val revealed loss of function through a significant reduction in whole-cell current, but no dominant-negative effect. Three patients had a contrasting phenotype of Developmental Encephalopathy without seizures and different KCNC1 variants, all of which caused loss of function with reduced whole-cell currents. Evaluation of the variant p.Ala513Val (c.1538C > T) in the tenth case, suggested it was a variant of uncertain significance. INTERPRETATION These are the first reported cases of Developmental and Epileptic Encephalopathy due to KCNC1 mutation. The spectrum of phenotypes associated with KCNC1 is now broadened to include not only a Progressive Myoclonus Epilepsy, but an infantile onset Developmental and Epileptic Encephalopathy, as well as Developmental Encephalopathy without seizures. Loss of function is a key feature, but definitive electrophysiological separation of these phenotypes has not yet emerged.
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Affiliation(s)
- Jillian M. Cameron
- Epilepsy Research Centre, Department of MedicineUniversity of Melbourne, Austin HealthHeidelbergMelbourneAustralia
| | - Snezana Maljevic
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneMelbourneAustralia
| | - Umesh Nair
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneMelbourneAustralia
| | - Ye Htet Aung
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneMelbourneAustralia
| | - Benjamin Cogné
- L'institut du thoraxINSERM, CNRS, UNIV NantesNantesFrance
- Service de génétique medicaleCentre Hospitalier, Université de NantesNantesFrance
| | - Stéphane Bézieau
- L'institut du thoraxINSERM, CNRS, UNIV NantesNantesFrance
- Service de génétique medicaleCentre Hospitalier, Université de NantesNantesFrance
| | - Edward Blair
- Oxford Centre for Genomic Medicine, ACE BuildingNuffield Orthopaedic CentreWindmill RoadOxfordUnited Kingdom
| | - Bertrand Isidor
- L'institut du thoraxINSERM, CNRS, UNIV NantesNantesFrance
- Service de génétique medicaleCentre Hospitalier, Université de NantesNantesFrance
| | - Christiane Zweier
- Institute of Human GeneticsFriedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - André Reis
- Institute of Human GeneticsFriedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - Mary Kay Koenig
- Department of Paediatrics, Division of Child & Adolescent NeurologyThe University of Texas McGovern Medical SchoolHoustonTexas
| | - Timothy Maarup
- Southern California Permanente Medical GroupPasadenaCalifornia
| | - Dean Sarco
- Southern California Permanente Medical GroupPasadenaCalifornia
| | - Alexandra Afenjar
- Centre de référence des malformations et maladies congénitales du cervelet, Département de génétique médicaleSorbonne Université, GRC ConCer‐LD, AP‐HP, Hôpital Armand TrousseauF‐75012ParisFrance
| | | | - Mary Kukolich
- Genetics DepartmentCook Children’s Health Care SystemFort WorthTexas
| | | | - Caroline Nava
- Département de GénétiqueSorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, AP‐HP, Hôpital de la Pitié SalpêtrièreF‐75013ParisFrance
| | - Bénédicte Héron
- Sorbonne Université, GRC N°19, Service de Neuropediatrie, Hôpital Trousseau La Roche Guyon (APHP)La Roche GuyonFrance
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneMelbourneAustralia
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of MedicineUniversity of Melbourne, Austin HealthHeidelbergMelbourneAustralia
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26
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Namikawa K, Dorigo A, Zagrebelsky M, Russo G, Kirmann T, Fahr W, Dübel S, Korte M, Köster RW. Modeling Neurodegenerative Spinocerebellar Ataxia Type 13 in Zebrafish Using a Purkinje Neuron Specific Tunable Coexpression System. J Neurosci 2019; 39:3948-3969. [PMID: 30862666 PMCID: PMC6520513 DOI: 10.1523/jneurosci.1862-18.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 02/19/2019] [Accepted: 02/25/2019] [Indexed: 12/17/2022] Open
Abstract
Purkinje cells (PCs) are primarily affected in neurodegenerative spinocerebellar ataxias (SCAs). For generating animal models for SCAs, genetic regulatory elements specifically targeting PCs are required, thereby linking pathological molecular effects with impaired function and organismic behavior. Because cerebellar anatomy and function are evolutionary conserved, zebrafish represent an excellent model to study SCAs in vivo We have isolated a 258 bp cross-species PC-specific enhancer element that can be used in a bidirectional manner for bioimaging of transgene-expressing PCs in zebrafish (both sexes) with variable copy numbers for tuning expression strength. Emerging ectopic expression at high copy numbers can be further eliminated by repurposing microRNA-mediated posttranslational mRNA regulation.Subsequently, we generated a transgenic SCA type 13 (SCA13) model, using a zebrafish-variant mimicking a human pathological SCA13R420H mutation, resulting in cell-autonomous progressive PC degeneration linked to cerebellum-driven eye-movement deficits as observed in SCA patients. This underscores that investigating PC-specific cerebellar neuropathologies in zebrafish allows for interconnecting bioimaging of disease mechanisms with behavioral analysis suitable for therapeutic compound testing.SIGNIFICANCE STATEMENT SCA13 patients carrying a KCNC3R420H allele have been shown to display mid-onset progressive cerebellar atrophy, but genetic modeling of SCA13 by expressing this pathogenic mutant in different animal models has not resulted in neuronal degeneration so far; likely because the transgene was expressed in heterologous cell types. We developed a genetic system for tunable PC-specific coexpression of several transgenes to manipulate and simultaneously monitor cerebellar PCs. We modeled a SCA13 zebrafish accessible for bioimaging to investigate disease progression, revealing robust PC degeneration, resulting in impaired eye movement. Our transgenic zebrafish mimicking both neuropathological and behavioral changes manifested in SCA-affected patients will be suitable for investigating causes of cerebellar diseases in vivo from the molecular to the behavioral level.
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Affiliation(s)
| | | | - Marta Zagrebelsky
- Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig 38106, Germany
| | - Giulio Russo
- Cellular and Molecular Neurobiology
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technical University Braunschweig 38106, Germany, and
| | | | - Wieland Fahr
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technical University Braunschweig 38106, Germany, and
| | - Stefan Dübel
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technical University Braunschweig 38106, Germany, and
| | - Martin Korte
- Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig 38106, Germany
- Research Group Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, Braunschweig 38106, Germany
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27
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Chopra R, Wasserman AH, Pulst SM, De Zeeuw CI, Shakkottai VG. Protein kinase C activity is a protective modifier of Purkinje neuron degeneration in cerebellar ataxia. Hum Mol Genet 2019; 27:1396-1410. [PMID: 29432535 DOI: 10.1093/hmg/ddy050] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/05/2018] [Indexed: 11/13/2022] Open
Abstract
Among the many types of neurons expressing protein kinase C (PKC) enzymes, cerebellar Purkinje neurons are particularly reliant on appropriate PKC activity for maintaining homeostasis. The importance of PKC enzymes in Purkinje neuron health is apparent as mutations in PRKCG (encoding PKCγ) cause cerebellar ataxia. PRKCG has also been identified as an important node in ataxia gene networks more broadly, but the functional role of PKC in other forms of ataxia remains unexplored, and the mechanisms by which PKC isozymes regulate Purkinje neuron health are not well understood. Here, we investigated how PKC activity influences neurodegeneration in inherited ataxia. Using mouse models of spinocerebellar ataxia type 1 (SCA1) and 2 (SCA2) we identify an increase in PKC-mediated substrate phosphorylation in two different forms of inherited cerebellar ataxia. Normalizing PKC substrate phosphorylation in SCA1 and SCA2 mice accelerates degeneration, suggesting that the increased activity observed in these models is neuroprotective. We also find that increased phosphorylation of PKC targets limits Purkinje neuron membrane excitability, suggesting that PKC activity may support Purkinje neuron health by moderating excitability. These data suggest a functional role for PKC enzymes in ataxia gene networks, and demonstrate that increased PKC activity is a protective modifier of degeneration in inherited cerebellar ataxia.
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Affiliation(s)
- Ravi Chopra
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Aaron H Wasserman
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT 84132, USA
| | - Chris I De Zeeuw
- Netherlands Institute for Neuroscience, Amsterdam 1105 CA, The Netherlands.,Department of Neuroscience, Erasmus MC, Rotterdam 3015 GE, The Netherlands
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
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28
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In Vivo Analysis of Potassium Channelopathies: Loose Patch Recording of Purkinje Cell Firing in Living, Awake Zebrafish. Methods Mol Biol 2018; 1684:237-252. [PMID: 29058196 DOI: 10.1007/978-1-4939-7362-0_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
Zebrafish is a lower vertebrate model organism that facilitates integrative analysis of the in vivo effects of potassium and other ion channel mutations at the molecular, cellular, developmental, circuit, systems, and behavioral levels of analysis. Here, we describe a method for extracellular, loose patch electrophysiological recording of electrical activity in cerebellar Purkinje cells in living, awake zebrafish, with the goal of investigating pathological mechanisms underlying channelopathies or other diseases that disrupt cerebellar function. Purkinje cell excitability and a functional cerebellar circuit develop rapidly in zebrafish and show strong conservation with the mammalian cerebellum.
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29
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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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30
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Bertini E, Zanni G, Boltshauser E. Nonprogressive congenital ataxias. HANDBOOK OF CLINICAL NEUROLOGY 2018; 155:91-103. [PMID: 29891079 DOI: 10.1016/b978-0-444-64189-2.00006-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The terminology of nonprogressive congenital ataxia (NPCA) refers to a clinically and genetically heterogeneous group of disorders characterized by congenital or early-onset ataxia, but no progression or even improvement on follow-up. Ataxia is preceded by muscular hypotonia and delayed motor (and usually language) milestones. We exclude children with prenatal, perinatal, and postnatal acquired diseases, malformations other than cerebellar hypoplasia, and defined syndromic disorders. Patients with NPCA have a high prevalence of cognitive and language impairments, in addition to increased occurrence of seizures, ocular signs (nystagmus, strabismus), behavior changes, and microcephaly. Neuroimaging is variable, ranging from normal cerebellar anatomy to reduced cerebellar volume (hypoplasia in the proper sense), and enlarged interfolial spaces, potentially mimicking atrophy. The latter appearance is often called "hypoplasia" as well, in view of the static clinical course. Some patients had progressive enlargement of cerebellar fissures, but a nonprogressive course. There is no imaging-clinical-genetic correlation. Dominant, recessive, and X-linked inheritance is documented for NPCA. Here, we focus on the still rather short list of dominant and recessive genes associated with NPCA, identified in the last few years. With future advances in genetics, we expect a rapid expansion of knowledge in this field.
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Affiliation(s)
- Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy.
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - Eugen Boltshauser
- Department of Pediatric Neurology, University Children's Hospital, University of Zurich, Zurich, Switzerland
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31
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Kaczmarek LK, Zhang Y. Kv3 Channels: Enablers of Rapid Firing, Neurotransmitter Release, and Neuronal Endurance. Physiol Rev 2017; 97:1431-1468. [PMID: 28904001 PMCID: PMC6151494 DOI: 10.1152/physrev.00002.2017] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/24/2017] [Accepted: 05/05/2017] [Indexed: 12/11/2022] Open
Abstract
The intrinsic electrical characteristics of different types of neurons are shaped by the K+ channels they express. From among the more than 70 different K+ channel genes expressed in neurons, Kv3 family voltage-dependent K+ channels are uniquely associated with the ability of certain neurons to fire action potentials and to release neurotransmitter at high rates of up to 1,000 Hz. In general, the four Kv3 channels Kv3.1-Kv3.4 share the property of activating and deactivating rapidly at potentials more positive than other channels. Each Kv3 channel gene can generate multiple protein isoforms, which contribute to the high-frequency firing of neurons such as auditory brain stem neurons, fast-spiking GABAergic interneurons, and Purkinje cells of the cerebellum, and to regulation of neurotransmitter release at the terminals of many neurons. The different Kv3 channels have unique expression patterns and biophysical properties and are regulated in different ways by protein kinases. In this review, we cover the function, localization, and modulation of Kv3 channels and describe how levels and properties of the channels are altered by changes in ongoing neuronal activity. We also cover how the protein-protein interaction of these channels with other proteins affects neuronal functions, and how mutations or abnormal regulation of Kv3 channels are associated with neurological disorders such as ataxias, epilepsies, schizophrenia, and Alzheimer's disease.
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Affiliation(s)
- Leonard K Kaczmarek
- Departments of Pharmacology and of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Yalan Zhang
- Departments of Pharmacology and of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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32
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Gribkoff VK, Kaczmarek LK. The need for new approaches in CNS drug discovery: Why drugs have failed, and what can be done to improve outcomes. Neuropharmacology 2017; 120:11-19. [PMID: 26979921 PMCID: PMC5820030 DOI: 10.1016/j.neuropharm.2016.03.021] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/14/2016] [Accepted: 03/11/2016] [Indexed: 12/31/2022]
Abstract
An important goal of biomedical research is to translate basic research findings into useful medical advances. In the field of neuropharmacology this requires understanding disease mechanisms as well as the effects of drugs and other compounds on neuronal function. Our hope is that this information will result in new or improved treatment for CNS disease. Despite great progress in our understanding of the structure and functions of the CNS, the discovery of new drugs and their clinical development for many CNS disorders has been problematic. As a result, CNS drug discovery and development programs have been subjected to significant cutbacks and eliminations over the last decade. While there has been recent resurgence of interest in CNS targets, these past changes in priority of the pharmaceutical and biotech industries reflect several well-documented realities. CNS drugs in general have higher failure rates than non-CNS drugs, both preclinically and clinically, and in some areas, such as the major neurodegenerative diseases, the clinical failure rate for disease-modifying treatments has been 100%. The development times for CNS drugs are significantly longer for those drugs that are approved, and post-development regulatory review is longer. In this introduction we review some of the reasons for failure, delineating both scientific and technical realities, some unique to the CNS, that have contributed to this. We will focus on major neurodegenerative disorders, which affect millions, attract most of the headlines, and yet have witnessed the fewest successes. We will suggest some changes that, when coupled with the approaches discussed in the rest of this special volume, may improve outcomes in future CNS-targeted drug discovery and development efforts. This article is part of the Special Issue entitled "Beyond small molecules for neurological disorders".
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Affiliation(s)
- Valentin K Gribkoff
- Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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33
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Forsythe ID. Editorial. J Physiol 2016; 594:4469-70. [DOI: 10.1113/jp272724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ian D. Forsythe
- Department of Neuroscience, Psychology & Behaviour; University of Leicester; UK
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34
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Zhang Y, Zhang XF, Fleming MR, Amiri A, El-Hassar L, Surguchev AA, Hyland C, Jenkins DP, Desai R, Brown MR, Gazula VR, Waters MF, Large CH, Horvath TL, Navaratnam D, Vaccarino FM, Forscher P, Kaczmarek LK. Kv3.3 Channels Bind Hax-1 and Arp2/3 to Assemble a Stable Local Actin Network that Regulates Channel Gating. Cell 2016; 165:434-448. [PMID: 26997484 PMCID: PMC4826296 DOI: 10.1016/j.cell.2016.02.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 11/13/2015] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
Abstract
Mutations in the Kv3.3 potassium channel (KCNC3) cause cerebellar neurodegeneration and impair auditory processing. The cytoplasmic C terminus of Kv3.3 contains a proline-rich domain conserved in proteins that activate actin nucleation through Arp2/3. We found that Kv3.3 recruits Arp2/3 to the plasma membrane, resulting in formation of a relatively stable cortical actin filament network resistant to cytochalasin D that inhibits fast barbed end actin assembly. These Kv3.3-associated actin structures are required to prevent very rapid N-type channel inactivation during short depolarizations of the plasma membrane. The effects of Kv3.3 on the actin cytoskeleton are mediated by the binding of the cytoplasmic C terminus of Kv3.3 to Hax-1, an anti-apoptotic protein that regulates actin nucleation through Arp2/3. A human Kv3.3 mutation within a conserved proline-rich domain produces channels that bind Hax-1 but are impaired in recruiting Arp2/3 to the plasma membrane, resulting in growth cones with deficient actin veils in stem cell-derived neurons.
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Affiliation(s)
- Yalan Zhang
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Xiao-Feng Zhang
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Matthew R. Fleming
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Anahita Amiri
- Department of Child Study Center and Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Lynda El-Hassar
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Alexei A. Surguchev
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Callen Hyland
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - David P. Jenkins
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Rooma Desai
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Maile R. Brown
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Valeswara-Rao Gazula
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Michael F. Waters
- Department of Neurology, University of Florida College of Medicine, HSC Box 100236, Gainesville, FL 32610-0236
| | - Charles H. Large
- Autifony Therapeutics Limited, Imperial College Incubator, Level 1 Bessemer Building, London, SW7 2AZ UK
| | - Tamas L. Horvath
- Department of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Dhasakumar Navaratnam
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Flora M. Vaccarino
- Department of Child Study Center and Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Paul Forscher
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
| | - Leonard K. Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520
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35
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Transduction Profile of the Marmoset Central Nervous System Using Adeno-Associated Virus Serotype 9 Vectors. Mol Neurobiol 2016; 54:1745-1758. [DOI: 10.1007/s12035-016-9777-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 02/03/2016] [Indexed: 01/22/2023]
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