1
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Fox PM, Malepati S, Manaster L, Rossignol E, Noebels JL. Developing a pathway to clinical trials for CACNA1A-related epilepsies: A patient organization perspective. THERAPEUTIC ADVANCES IN RARE DISEASE 2024; 5:26330040241245725. [PMID: 38681799 PMCID: PMC11047245 DOI: 10.1177/26330040241245725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 03/15/2024] [Indexed: 05/01/2024]
Abstract
CACNA1A-related disorders are rare neurodevelopmental disorders linked to variants in the CACNA1A gene. This gene encodes the α1 subunit of the P/Q-type calcium channel Cav2.1, which is globally expressed in the brain and crucial for fast synaptic neurotransmission. The broad spectrum of CACNA1A-related neurological disorders includes developmental and epileptic encephalopathies, familial hemiplegic migraine type 1, episodic ataxia type 2, spinocerebellar ataxia type 6, together with unclassified presentations with developmental delay, ataxia, intellectual disability, autism spectrum disorder, and language impairment. The severity of each disorder is also highly variable. The spectrum of CACNA1A-related seizures is broad across both loss-of-function and gain-of-function variants and includes absence seizures, focal seizures with altered consciousness, generalized tonic-clonic seizures, tonic seizures, status epilepticus, and infantile spasms. Furthermore, over half of CACNA1A-related epilepsies are refractory to current therapies. To date, almost 1700 CACNA1A variants have been reported in ClinVar, with over 400 listed as Pathogenic or Likely Pathogenic, but with limited-to-no clinical or functional data. Robust genotype-phenotype studies and impacts of variants on protein structure and function have also yet to be established. As a result, there are few definitive treatment options for CACNA1A-related epilepsies. The CACNA1A Foundation has set out to change the landscape of available and effective treatments and improve the quality of life for those living with CACNA1A-related disorders, including epilepsy. Established in March 2020, the Foundation has built a robust preclinical toolbox that includes patient-derived induced pluripotent stem cells and novel disease models, launched clinical trial readiness initiatives, and organized a global CACNA1A Research Network. This Research Network is currently composed of over 60 scientists and clinicians committed to collaborating to accelerate the path to CACNA1A-specific treatments and one day, a cure.
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Affiliation(s)
- Pangkong M. Fox
- CACNA1A Foundation, Inc., 31 Pt Road, Norwalk, CT 06854, USA
| | | | | | - Elsa Rossignol
- CACNA1A Foundation, Inc., Norwalk, CT, USA
- CHU Sainte-Justine Research Center, Departments of Neurosciences and Pediatrics, University of Montreal, Montreal, QC, Canada
| | - Jeffrey L. Noebels
- CACNA1A Foundation, Inc., Norwalk, CT, USA
- Blue Bird Circle Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
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2
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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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3
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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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4
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Kolesnikova TO, Demin KA, Costa FV, Zabegalov KN, de Abreu MS, Gerasimova EV, Kalueff AV. Towards Zebrafish Models of CNS Channelopathies. Int J Mol Sci 2022; 23:ijms232213979. [PMID: 36430455 PMCID: PMC9693542 DOI: 10.3390/ijms232213979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/06/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
Channelopathies are a large group of systemic disorders whose pathogenesis is associated with dysfunctional ion channels. Aberrant transmembrane transport of K+, Na+, Ca2+ and Cl- by these channels in the brain induces central nervous system (CNS) channelopathies, most commonly including epilepsy, but also migraine, as well as various movement and psychiatric disorders. Animal models are a useful tool for studying pathogenesis of a wide range of brain disorders, including channelopathies. Complementing multiple well-established rodent models, the zebrafish (Danio rerio) has become a popular translational model organism for neurobiology, psychopharmacology and toxicology research, and for probing mechanisms underlying CNS pathogenesis. Here, we discuss current prospects and challenges of developing genetic, pharmacological and other experimental models of major CNS channelopathies based on zebrafish.
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Affiliation(s)
| | - Konstantin A. Demin
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, 197341 St. Petersburg, Russia
| | - Fabiano V. Costa
- Neurobiology Program, Sirius University of Science and Technology, 354349 Sochi, Russia
| | | | - Murilo S. de Abreu
- Moscow Institute of Physics and Technology, 141701 Moscow, Russia
- Correspondence: (M.S.d.A.); (A.V.K.); Tel.: +55-54-99605-9807 (M.S.d.A.); +1-240-899-9571 (A.V.K.); Fax: +1-240-899-9571 (A.V.K.)
| | - Elena V. Gerasimova
- Neurobiology Program, Sirius University of Science and Technology, 354349 Sochi, Russia
| | - Allan V. Kalueff
- Neurobiology Program, Sirius University of Science and Technology, 354349 Sochi, Russia
- Institute of Translational Biomedicine, St. Petersburg State University, 199034 St. Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, 197341 St. Petersburg, Russia
- Moscow Institute of Physics and Technology, 141701 Moscow, Russia
- Laboratory of Preclinical Bioscreening, Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of Russian Federation, 197758 St. Petersburg, Russia
- Ural Federal University, 620002 Yekaterinburg, Russia
- Scientific Research Institute of Neurosciences and Medicine, 630117 Novosibirsk, Russia
- Correspondence: (M.S.d.A.); (A.V.K.); Tel.: +55-54-99605-9807 (M.S.d.A.); +1-240-899-9571 (A.V.K.); Fax: +1-240-899-9571 (A.V.K.)
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5
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Meserve JH, Nelson JC, Marsden KC, Hsu J, Echeverry FA, Jain RA, Wolman MA, Pereda AE, Granato M. A forward genetic screen identifies Dolk as a regulator of startle magnitude through the potassium channel subunit Kv1.1. PLoS Genet 2021; 17:e1008943. [PMID: 34061829 PMCID: PMC8195410 DOI: 10.1371/journal.pgen.1008943] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 06/11/2021] [Accepted: 05/04/2021] [Indexed: 11/19/2022] Open
Abstract
The acoustic startle response is an evolutionarily conserved avoidance behavior. Disruptions in startle behavior, particularly startle magnitude, are a hallmark of several human neurological disorders. While the neural circuitry underlying startle behavior has been studied extensively, the repertoire of genes and genetic pathways that regulate this locomotor behavior has not been explored using an unbiased genetic approach. To identify such genes, we took advantage of the stereotypic startle behavior in zebrafish larvae and performed a forward genetic screen coupled with whole genome analysis. We uncovered mutations in eight genes critical for startle behavior, including two genes encoding proteins associated with human neurological disorders, Dolichol kinase (Dolk), a broadly expressed regulator of the glycoprotein biosynthesis pathway, and the potassium Shaker-like channel subunit Kv1.1. We demonstrate that Kv1.1 and Dolk play critical roles in the spinal cord to regulate movement magnitude during the startle response and spontaneous swim movements. Moreover, we show that Kv1.1 protein is mislocalized in dolk mutants, suggesting they act in a common genetic pathway. Combined, our results identify a diverse set of eight genes, all associated with human disorders, that regulate zebrafish startle behavior and reveal a previously unappreciated role for Dolk and Kv1.1 in regulating movement magnitude via a common genetic pathway.
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Affiliation(s)
- Joy H. Meserve
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jessica C. Nelson
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kurt C. Marsden
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jerry Hsu
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Fabio A. Echeverry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Roshan A. Jain
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Marc A. Wolman
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Alberto E. Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Michael Granato
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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6
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Quelle-Regaldie A, Sobrido-Cameán D, Barreiro-Iglesias A, Sobrido MJ, Sánchez L. Zebrafish Models of Autosomal Dominant Ataxias. Cells 2021; 10:421. [PMID: 33671313 PMCID: PMC7922657 DOI: 10.3390/cells10020421] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/13/2022] Open
Abstract
Hereditary dominant ataxias are a heterogeneous group of neurodegenerative conditions causing cerebellar dysfunction and characterized by progressive motor incoordination. Despite many efforts put into the study of these diseases, there are no effective treatments yet. Zebrafish models are widely used to characterize neuronal disorders due to its conserved vertebrate genetics that easily support genetic edition and their optic transparency that allows observing the intact CNS and its connections. In addition, its small size and external fertilization help to develop high throughput assays of candidate drugs. Here, we discuss the contributions of zebrafish models to the study of dominant ataxias defining phenotypes, genetic function, behavior and possible treatments. In addition, we review the zebrafish models created for X-linked repeat expansion diseases X-fragile/fragile-X tremor ataxia. Most of the models reviewed here presented neuronal damage and locomotor deficits. However, there is a generalized lack of zebrafish adult heterozygous models and there are no knock-in zebrafish models available for these diseases. The models created for dominant ataxias helped to elucidate gene function and mechanisms that cause neuronal damage. In the future, the application of new genetic edition techniques would help to develop more accurate zebrafish models of dominant ataxias.
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Affiliation(s)
- Ana Quelle-Regaldie
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary Science, Universidade of Santiago de Compostela, 27002 Lugo, Spain; (A.Q.-R.); (L.S.)
| | - Daniel Sobrido-Cameán
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain;
| | - Antón Barreiro-Iglesias
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain;
| | - María Jesús Sobrido
- Instituto de Investigación Biomédica de A Coruña (INIBIC), Servicio Galego de Saúde, 15006 Coruña, Spain;
| | - Laura Sánchez
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary Science, Universidade of Santiago de Compostela, 27002 Lugo, Spain; (A.Q.-R.); (L.S.)
- Preclinical Animal Models Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
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7
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Gauberg J, Abdallah S, Elkhatib W, Harracksingh AN, Piekut T, Stanley EF, Senatore A. Conserved biophysical features of the Ca V2 presynaptic Ca 2+ channel homologue from the early-diverging animal Trichoplax adhaerens. J Biol Chem 2020; 295:18553-18578. [PMID: 33097592 PMCID: PMC7939481 DOI: 10.1074/jbc.ra120.015725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
The dominant role of CaV2 voltage-gated calcium channels for driving neurotransmitter release is broadly conserved. Given the overlapping functional properties of CaV2 and CaV1 channels, and less so CaV3 channels, it is unclear why there have not been major shifts toward dependence on other CaV channels for synaptic transmission. Here, we provide a structural and functional profile of the CaV2 channel cloned from the early-diverging animal Trichoplax adhaerens, which lacks a nervous system but possesses single gene homologues for CaV1-CaV3 channels. Remarkably, the highly divergent channel possesses similar features as human CaV2.1 and other CaV2 channels, including high voltage-activated currents that are larger in external Ba2+ than in Ca2+; voltage-dependent kinetics of activation, inactivation, and deactivation; and bimodal recovery from inactivation. Altogether, the functional profile of Trichoplax CaV2 suggests that the core features of presynaptic CaV2 channels were established early during animal evolution, after CaV1 and CaV2 channels emerged via proposed gene duplication from an ancestral CaV1/2 type channel. The Trichoplax channel was relatively insensitive to mammalian CaV2 channel blockers ω-agatoxin-IVA and ω-conotoxin-GVIA and to metal cation blockers Cd2+ and Ni2+ Also absent was the capacity for voltage-dependent G-protein inhibition by co-expressed Trichoplax Gβγ subunits, which nevertheless inhibited the human CaV2.1 channel, suggesting that this modulatory capacity evolved via changes in channel sequence/structure, and not G proteins. Last, the Trichoplax channel was immunolocalized in cells that express an endomorphin-like peptide implicated in cell signaling and locomotive behavior and other likely secretory cells, suggesting contributions to regulated exocytosis.
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Affiliation(s)
- Julia Gauberg
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Salsabil Abdallah
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alicia N Harracksingh
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Thomas Piekut
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Elise F Stanley
- Laboratory of Synaptic Transmission, Krembil Research Institute, Toronto, Ontario, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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8
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Primary and secondary motoneurons use different calcium channel types to control escape and swimming behaviors in zebrafish. Proc Natl Acad Sci U S A 2020; 117:26429-26437. [PMID: 33020266 DOI: 10.1073/pnas.2015866117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The escape response and rhythmic swimming in zebrafish are distinct behaviors mediated by two functionally distinct motoneuron (Mn) types. The primary (1°Mn) type depresses and has a large quantal content (Qc) and a high release probability (Pr). Conversely, the secondary (2°Mn) type facilitates and has low and variable Qc and Pr. This functional duality matches well the distinct associated behaviors, with the 1°Mn providing the strong, singular C bend initiating escape and the 2°Mn conferring weaker, rhythmic contractions. Contributing to these functional distinctions is our identification of P/Q-type calcium channels mediating transmitter release in 1°Mns and N-type channels in 2°Mns. Remarkably, despite these functional and behavioral distinctions, all ∼15 individual synapses on each muscle cell are shared by a 1°Mn bouton and at least one 2°Mn bouton. This blueprint of synaptic sharing provides an efficient way of controlling two different behaviors at the level of a single postsynaptic cell.
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9
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Tyagi S, Ribera AB, Bannister RA. Zebrafish as a Model System for the Study of Severe Ca V2.1 (α 1A) Channelopathies. Front Mol Neurosci 2020; 12:329. [PMID: 32116539 PMCID: PMC7018710 DOI: 10.3389/fnmol.2019.00329] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/23/2019] [Indexed: 02/02/2023] Open
Abstract
The P/Q-type CaV2.1 channel regulates neurotransmitter release at neuromuscular junctions (NMJ) and many central synapses. CACNA1A encodes the pore-containing α1A subunit of CaV2.1 channels. In humans, de novo CACNA1A mutations result in a wide spectrum of neurological, neuromuscular, and movement disorders, such as familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2 (EA2), as well as a more recently discovered class of more severe disorders, which are characterized by ataxia, hypotonia, cerebellar atrophy, and cognitive/developmental delay. Heterologous expression of CaV2.1 channels has allowed for an understanding of the consequences of CACNA1A missense mutations on channel function. In contrast, a mechanistic understanding of how specific CACNA1A mutations lead in vivo to the resultant phenotypes is lacking. In this review, we present the zebrafish as a model to both study in vivo mechanisms of CACNA1A mutations that result in synaptic and behavioral defects and to screen for effective drug therapies to combat these and other CaV2.1 channelopathies.
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Affiliation(s)
- Sidharth Tyagi
- Medical Scientist Training Program, Yale University School of Medicine, New Haven, CT, United States
| | - Angeles B Ribera
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Roger A Bannister
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, United States
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10
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Gawel K, Turski WA, van der Ent W, Mathai BJ, Kirstein-Smardzewska KJ, Simonsen A, Esguerra CV. Phenotypic Characterization of Larval Zebrafish (Danio rerio) with Partial Knockdown of the cacna1a Gene. Mol Neurobiol 2019; 57:1904-1916. [PMID: 31875924 PMCID: PMC7118054 DOI: 10.1007/s12035-019-01860-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/15/2019] [Indexed: 12/18/2022]
Abstract
The CACNA1A gene encodes the pore-forming α1 subunit of voltage-gated P/Q type Ca2+ channels (Cav2.1). Mutations in this gene, among others, have been described in patients and rodents suffering from absence seizures and episodic ataxia type 2 with/without concomitant seizures. In this study, we aimed for the first time to assess phenotypic and behavioral alterations in larval zebrafish with partial cacna1aa knockdown, placing special emphasis on changes in epileptiform-like electrographic discharges in larval brains. Whole-mount in situ hybridization analysis revealed expression of cacna1aa in the optic tectum and medulla oblongata of larval zebrafish at 4 and 5 days post-fertilization. Next, microinjection of two antisense morpholino oligomers (individually or in combination) targeting all splice variants of cacna1aa into fertilized zebrafish eggs resulted in dose-dependent mortality and decreased or absent touch response. Over 90% knockdown of cacna1aa on protein level induced epileptiform-like discharges in the optic tectum of larval zebrafish brains. Incubation of morphants with antiseizure drugs (sodium valproate, ethosuximide, lamotrigine, topiramate) significantly decreased the number and, in some cases, cumulative duration of epileptiform-like discharges. In this context, sodium valproate seemed to be the least effective. Carbamazepine did not affect the number and duration of epileptiform-like discharges. Altogether, our data indicate that cacna1aa loss-of-function zebrafish may be considered a new model of absence epilepsy and may prove useful both for the investigation of Cacna1a-mediated epileptogenesis and for in vivo drug screening.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.,Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | - Waldemar A Turski
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Benan J Mathai
- Faculty of Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Karolina J Kirstein-Smardzewska
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Anne Simonsen
- Faculty of Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway. .,School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Sem Sælandsvei 24, 0371, Oslo, Norway.
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11
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Mahmoud MAM, Abdel-Mohsein HS. Hysterical tetracycline in intensive poultry farms accountable for substantial gene resistance, health and ecological risk in Egypt- manure and fish. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113039. [PMID: 31521994 DOI: 10.1016/j.envpol.2019.113039] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/05/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Although the poultry production sector plays a key role in sustaining the majority of animal protein demand in Egypt, the deleterious effects of widespread antibiotic resistance on health and environment are currently not well recognized. Litter and dropping samples from broiler and layer poultry farms as well as, tilapia samples from the Nile River and aquaculture farms were collected from Upper Egypt. Samples were extracted and examined for tetracycline residues [tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC) and doxycycline (DC)] using HPLC. In addition, tetracycline resistance genes [tet (M), tet (W), tet (Q) and tet (G)] were screened from pooled intestinal contents collected from twelve broiler farms in Upper Egypt. The antibiotic resistance genes results revealed that tet (W) was confirmed to be expressed in all intestinal samples. In contrast, tet (Q) and tet (M) were detected only in 42% and 17% of the samples, respectively. CTC and OTC were the antimicrobial compounds with the highest concentrations in poultry litter and droppings, with concentrations of 6.05 and 2.47 μg g-1 (CTC) and 5.9 and 1.33 μg g-1 (OTC), respectively. However, the concentrations of DC were significantly higher than those of the other compounds in both aquaculture and Nile River tilapia. The tetracycline residue levels in aquaculture tilapia were significantly higher than those in Nile River tilapia. The hazard quotients (HQs) exceeded 1 for OTC, CTC and DC, which highlights the great risk of using broiler litter to fertilize agricultural land. Moreover, the presence of DC and CTC indicates that consumption of aquaculture tilapia poses a considerable health risk. Therefore, poultry litter or droppings containing tetracycline residues and tet resistance determinants used for aquaculture or as farmland fertilizers could be major sources of antibiotic resistance in fish, humans and environment.
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Affiliation(s)
- Manal A M Mahmoud
- Department of Animal, Poultry Hygiene and Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, 71526, Egypt.
| | - Hosnia S Abdel-Mohsein
- Department of Animal, Poultry Hygiene and Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, 71526, Egypt
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12
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Brehm P, Wen H. Zebrafish neuromuscular junction: The power of N. Neurosci Lett 2019; 713:134503. [PMID: 31557523 DOI: 10.1016/j.neulet.2019.134503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/11/2019] [Accepted: 09/16/2019] [Indexed: 11/26/2022]
Abstract
In the early 1950s, Katz and his colleagues capitalized on the newly developed intracellular microelectrode recording technique to investigate synaptic transmission. For study they chose frog neuromuscular junction (NMJ), which was ideally suited due to the accessibility and large size of the muscle cells. Paradoxically, the large size precluded the use of next generation patch clamp technology. Consequently, electrophysiological study of synaptic function shifted to small central synapses made amenable by patch clamp. Recently, however, the unique features offered by zebrafish have rekindled interest in the NMJ as a model for electrophysiological study of synaptic transmission. The small muscle size and synaptic simplicity provide the singular opportunity to perform in vivo spinal motoneuron-target muscle patch clamp recordings. Additional incentive is provided by zebrafish lines harboring mutations in key synaptic proteins, many of which are embryonic lethal in mammals, but all of which are able to survive well past synapse maturation in zebrafish. This mini-review will highlight features that set zebrafish NMJs apart from traditional NMJs. We also draw into focus findings that offer the promise of identifying features that define release sites, which serve to set the upper limit of transmitter release. Since its conception several candidates representing release sites have been proposed, most of which are based on distinctions among vesicle pools in their state of readiness for release. However, models based on distinctions among vesicles have become enormously complicated and none adequately account for setting an upper limit for exocytosis in response to an action potential (AP). Specifically, findings from zebrafish NMJ point to an alternative model, positing that elements other than vesicles per se set the upper limits of release.
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Affiliation(s)
- Paul Brehm
- Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA.
| | - Hua Wen
- Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, USA
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13
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Tyagi S, Bendrick TR, Filipova D, Papadopoulos S, Bannister RA. A mutation in Ca V2.1 linked to a severe neurodevelopmental disorder impairs channel gating. J Gen Physiol 2019; 151:850-859. [PMID: 31015257 PMCID: PMC6571999 DOI: 10.1085/jgp.201812237] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 02/04/2019] [Accepted: 03/18/2019] [Indexed: 01/07/2023] Open
Abstract
Ca2+ flux into axon terminals via P-/Q-type CaV2.1 channels is the trigger for neurotransmitter vesicle release at neuromuscular junctions (NMJs) and many central synapses. Recently, an arginine to proline substitution (R1673P) in the S4 voltage-sensing helix of the fourth membrane-bound repeat of CaV2.1 was linked to a severe neurological disorder characterized by generalized hypotonia, ataxia, cerebellar atrophy, and global developmental delay. The R1673P mutation was proposed to cause a gain of function in CaV2.1 leading to neuronal Ca2+ toxicity based on the ability of the mutant channel to rescue the photoreceptor response in CaV2.1-deficient Drosophila cacophony larvae. Here, we show that the corresponding mutation in rat CaV2.1 (R1624P) causes a profound loss of channel function; voltage-clamp analysis of tsA-201 cells expressing this mutant channel revealed an ∼25-mV depolarizing shift in the voltage dependence of activation. This alteration in activation implies that a significant fraction of CaV2.1 channels resident in presynaptic terminals are unlikely to open in response to an action potential, thereby increasing the probability of synaptic failure at both NMJs and central synapses. Indeed, the mutant channel supported only minimal Ca2+ flux in response to an action potential-like waveform. Application of GV-58, a compound previously shown to stabilize the open state of wild-type CaV2.1 channels, partially restored Ca2+ current by shifting mutant activation to more hyperpolarizing potentials and slowing deactivation. Consequently, GV-58 also rescued a portion of Ca2+ flux during action potential-like stimuli. Thus, our data raise the possibility that therapeutic agents that increase channel open probability or prolong action potential duration may be effective in combatting this and other severe neurodevelopmental disorders caused by loss-of-function mutations in CaV2.1.
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Affiliation(s)
- Sidharth Tyagi
- Department of Medicine-Cardiology Division, University of Colorado School of Medicine, Aurora, CO
| | - Tyler R Bendrick
- Department of Medicine-Cardiology Division, University of Colorado School of Medicine, Aurora, CO
| | - Dilyana Filipova
- Department of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Symeon Papadopoulos
- Department of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado School of Medicine, Aurora, CO
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14
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Wu M, White HV, Boehm BA, Meriney CJ, Kerrigan K, Frasso M, Liang M, Gotway EM, Wilcox MR, Johnson JW, Wipf P, Meriney SD. New Cav2 calcium channel gating modifiers with agonist activity and therapeutic potential to treat neuromuscular disease. Neuropharmacology 2017; 131:176-189. [PMID: 29246857 DOI: 10.1016/j.neuropharm.2017.12.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 11/28/2017] [Accepted: 12/10/2017] [Indexed: 12/13/2022]
Abstract
Voltage-gated calcium channels (VGCCs) are critical regulators of many cellular functions, including the activity-dependent release of chemical neurotransmitter from nerve terminals. At nerve terminals, the Cav2 family of VGCCs are closely positioned with neurotransmitter-containing synaptic vesicles. The relationship between calcium ions and transmitter release is such that even subtle changes in calcium flux through VGCCs have a strong influence on the magnitude of transmitter released. Therefore, modulators of the calcium influx at nerve terminals have the potential to strongly affect transmitter release at synapses. We have previously developed novel Cav2-selective VGCC gating modifiers (notably GV-58) that slow the deactivation of VGCC current, increasing total calcium ion flux. Here, we describe ten new gating modifiers based on the GV-58 structure that extend our understanding of the structure-activity relationship for this class of molecules and extend the range of modulation of channel activities. In particular, we show that one of these new compounds (MF-06) was more efficacious than GV-58, another (KK-75) acts more quickly on VGCCs than GV-58, and a third (KK-20) has a mix of increased speed and efficacy. A subset of these new VGCC agonist gating modifiers can increase transmitter release during action potentials at neuromuscular synapses, and as such, show potential as therapeutics for diseases with a presynaptic deficit that results in neuromuscular weakness. Further, several of these new compounds can be useful tool compounds for the study of VGCC gating and function.
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Affiliation(s)
- Man Wu
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Hayley V White
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Blake A Boehm
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Christopher J Meriney
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Kaylan Kerrigan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Michael Frasso
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Mary Liang
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Erika M Gotway
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Madeleine R Wilcox
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jon W Johnson
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Stephen D Meriney
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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15
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Fatigue in Rapsyn-Deficient Zebrafish Reflects Defective Transmitter Release. J Neurosci 2017; 36:10870-10882. [PMID: 27798141 DOI: 10.1523/jneurosci.0505-16.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 09/03/2016] [Indexed: 12/29/2022] Open
Abstract
Rapsyn-deficient myasthenic syndrome is characterized by a weakness in voluntary muscle contraction, a direct consequence of greatly reduced synaptic responses that result from poorly clustered acetylcholine receptors. As with other myasthenic syndromes, the general muscle weakness is also accompanied by use-dependent fatigue. Here, we used paired motor neuron target muscle patch-clamp recordings from a rapsyn-deficient mutant line of zebrafish to explore for the first time the mechanisms causal to fatigue. We find that synaptic responses in mutant fish can follow faithfully low-frequency stimuli despite the reduced amplitude. This is in part helped by a compensatory increase in the number of presynaptic release sites in the mutant fish. In response to high-frequency stimulation, both wild-type and mutant neuromuscular junctions depress to steady-state response levels, but the latter shows exaggerated depression. Analysis of the steady-state transmission revealed that vesicle reloading and release at individual release sites is significantly slower in mutant fish during high-frequency activities. Therefore, reductions in postsynaptic receptor density and compromised presynaptic release collectively serve to reduce synaptic strength to levels that fall below the threshold for muscle action potential generation, thus accounting for use-dependent fatigue. Our findings raise the possibility that defects in motor neuron function may also be at play in other myasthenic syndromes that have been mapped to mutations in muscle-specific proteins. SIGNIFICANCE STATEMENT Use-dependent fatigue accompanies many neuromuscular myasthenic syndromes, including muscle rapsyn deficiency. Here, using a rapsyn-deficient line of zebrafish, we performed paired motor neuron target muscle patch-clamp recordings to investigate the mechanisms causal to this phenomenon. Our findings indicate that the reduced postsynaptic receptor density resulting from defective rapsyn contributes to weakness, but is not solely responsible for use-dependent fatigue. Instead, we find unexpected involvement of altered transmitter release from the motor neuron. Specifically, slowed reloading of vesicle release sites leads to augmented synaptic depression during repeated action potentials. Even at moderate stimulus frequencies, the depression levels for evoked synaptic responses fall below the threshold for the generation of muscle action potentials. The associated contraction failures are manifest as use-dependent fatigue.
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16
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(S)-lacosamide inhibition of CRMP2 phosphorylation reduces postoperative and neuropathic pain behaviors through distinct classes of sensory neurons identified by constellation pharmacology. Pain 2017; 157:1448-1463. [PMID: 26967696 DOI: 10.1097/j.pain.0000000000000555] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chronic pain affects the life of millions of people. Current treatments have deleterious side effects. We have advanced a strategy for targeting protein interactions which regulate the N-type voltage-gated calcium (CaV2.2) channel as an alternative to direct channel block. Peptides uncoupling CaV2.2 interactions with the axonal collapsin response mediator protein 2 (CRMP2) were antinociceptive without effects on memory, depression, and reward/addiction. A search for small molecules that could recapitulate uncoupling of the CaV2.2-CRMP2 interaction identified (S)-lacosamide [(S)-LCM], the inactive enantiomer of the Food and Drug Administration-approved antiepileptic drug (R)-lacosamide [(R)-LCM, Vimpat]. We show that (S)-LCM, but not (R)-LCM, inhibits CRMP2 phosphorylation by cyclin dependent kinase 5, a step necessary for driving CaV2.2 activity, in sensory neurons. (S)-lacosamide inhibited depolarization-induced Ca influx with a low micromolar IC50. Voltage-clamp electrophysiology experiments demonstrated a commensurate reduction in Ca currents in sensory neurons after an acute application of (S)-LCM. Using constellation pharmacology, a recently described high content phenotypic screening platform for functional fingerprinting of neurons that uses subtype-selective pharmacological agents to elucidate cell-specific combinations (constellations) of key signaling proteins that define specific cell types, we investigated if (S)-LCM preferentially acts on certain types of neurons. (S)-lacosamide decreased the dorsal root ganglion neurons responding to mustard oil, and increased the number of cells responding to menthol. Finally, (S)-LCM reversed thermal hypersensitivity and mechanical allodynia in a model of postoperative pain, and 2 models of neuropathic pain. Thus, using (S)-LCM to inhibit CRMP2 phosphorylation is a novel and efficient strategy to treat pain, which works by targeting specific sensory neuron populations.
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Kozol RA, Abrams AJ, James DM, Buglo E, Yan Q, Dallman JE. Function Over Form: Modeling Groups of Inherited Neurological Conditions in Zebrafish. Front Mol Neurosci 2016; 9:55. [PMID: 27458342 PMCID: PMC4935692 DOI: 10.3389/fnmol.2016.00055] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/23/2016] [Indexed: 12/11/2022] Open
Abstract
Zebrafish are a unique cell to behavior model for studying the basic biology of human inherited neurological conditions. Conserved vertebrate genetics and optical transparency provide in vivo access to the developing nervous system as well as high-throughput approaches for drug screens. Here we review zebrafish modeling for two broad groups of inherited conditions that each share genetic and molecular pathways and overlap phenotypically: neurodevelopmental disorders such as Autism Spectrum Disorders (ASD), Intellectual Disability (ID) and Schizophrenia (SCZ), and neurodegenerative diseases, such as Cerebellar Ataxia (CATX), Hereditary Spastic Paraplegia (HSP) and Charcot-Marie Tooth Disease (CMT). We also conduct a small meta-analysis of zebrafish orthologs of high confidence neurodevelopmental disorder and neurodegenerative disease genes by looking at duplication rates and relative protein sizes. In the past zebrafish genetic models of these neurodevelopmental disorders and neurodegenerative diseases have provided insight into cellular, circuit and behavioral level mechanisms contributing to these conditions. Moving forward, advances in genetic manipulation, live imaging of neuronal activity and automated high-throughput molecular screening promise to help delineate the mechanistic relationships between different types of neurological conditions and accelerate discovery of therapeutic strategies.
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Affiliation(s)
- Robert A. Kozol
- Department of Biology, University of MiamiCoral Gables, FL, USA
| | - Alexander J. Abrams
- Department of Human Genetics, John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation, University of MiamiMiami, FL, USA
| | - David M. James
- Department of Biology, University of MiamiCoral Gables, FL, USA
| | - Elena Buglo
- Department of Human Genetics, John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation, University of MiamiMiami, FL, USA
| | - Qing Yan
- Department of Biology, University of MiamiCoral Gables, FL, USA
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18
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Meijer L, Nelson DJ, Riazanski V, Gabdoulkhakova AG, Hery-Arnaud G, Le Berre R, Loaëc N, Oumata N, Galons H, Nowak E, Gueganton L, Dorothée G, Prochazkova M, Hall B, Kulkarni AB, Gray RD, Rossi AG, Witko-Sarsat V, Norez C, Becq F, Ravel D, Mottier D, Rault G. Modulating Innate and Adaptive Immunity by (R)-Roscovitine: Potential Therapeutic Opportunity in Cystic Fibrosis. J Innate Immun 2016; 8:330-49. [PMID: 26987072 PMCID: PMC4800827 DOI: 10.1159/000444256] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/25/2016] [Accepted: 01/25/2016] [Indexed: 12/17/2022] Open
Abstract
(R)-Roscovitine, a pharmacological inhibitor of kinases, is currently in phase II clinical trial as a drug candidate for the treatment of cancers, Cushing's disease and rheumatoid arthritis. We here review the data that support the investigation of (R)-roscovitine as a potential therapeutic agent for the treatment of cystic fibrosis (CF). (R)-Roscovitine displays four independent properties that may favorably combine against CF: (1) it partially protects F508del-CFTR from proteolytic degradation and favors its trafficking to the plasma membrane; (2) by increasing membrane targeting of the TRPC6 ion channel, it rescues acidification in phagolysosomes of CF alveolar macrophages (which show abnormally high pH) and consequently restores their bactericidal activity; (3) its effects on neutrophils (induction of apoptosis), eosinophils (inhibition of degranulation/induction of apoptosis) and lymphocytes (modification of the Th17/Treg balance in favor of the differentiation of anti-inflammatory lymphocytes and reduced production of various interleukins, notably IL-17A) contribute to the resolution of inflammation and restoration of innate immunity, and (4) roscovitine displays analgesic properties in animal pain models. The fact that (R)-roscovitine has undergone extensive preclinical safety/pharmacology studies, and phase I and II clinical trials in cancer patients, encourages its repurposing as a CF drug candidate.
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Affiliation(s)
- Laurent Meijer
- Centre de Perharidy, ManRos Therapeutics, Roscoff, France
| | - Deborah J. Nelson
- Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, Ill., USA
| | - Vladimir Riazanski
- Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, Ill., USA
| | - Aida G. Gabdoulkhakova
- Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, Ill., USA
| | - Geneviève Hery-Arnaud
- Unité de Bactériologie, Hôpital de la Cavale Blanche, CHRU Brest, Brest, France
- EA3882-LUBEM, Université de Brest, UFR de Médecine et des Sciences de la Santé, Brest, France
| | - Rozenn Le Berre
- EA3882-LUBEM, Université de Brest, UFR de Médecine et des Sciences de la Santé, Brest, France
- Département de Médecine Interne et Pneumologie, CHRU Brest, Brest, France
| | - Nadège Loaëc
- Centre de Perharidy, ManRos Therapeutics, Roscoff, France
| | - Nassima Oumata
- Centre de Perharidy, ManRos Therapeutics, Roscoff, France
| | - Hervé Galons
- Unité de Technologies Chimiques et Biologiques pour la Santé, Université Paris Descartes UMR-S 1022 INSERM, Paris, France
| | - Emmanuel Nowak
- Hôpital de la Cavale Blanche, CHRU Brest, Centre d'Investigation Clinique, INSERM CIC 1412, Brest, France
| | | | - Guillaume Dorothée
- Immune System, Neuroinflammation and Neurodegenerative Diseases Laboratory, Inflammation-Immunopathology-Biotherapy Department (DHU i2B), CdR Saint-Antoine, INSERM, UMRS 938, Paris, France
- Hôpital Saint-Antoine, CdR Saint-Antoine, UMRS 938, UPMC University Paris 06, Sorbonne Universités, Paris, France
| | - Michaela Prochazkova
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, NIH, Bethesda, Md., USA
| | - Bradford Hall
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, NIH, Bethesda, Md., USA
| | - Ashok B. Kulkarni
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, NIH, Bethesda, Md., USA
| | - Robert D. Gray
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh Medical School, Edinburgh, UK
| | - Adriano G. Rossi
- MRC Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh Medical School, Edinburgh, UK
| | | | - Caroline Norez
- Laboratoire Signalisation et Transports Ioniques Membranaires, CNRS, Université de Poitiers, Poitiers, France
| | - Frédéric Becq
- Laboratoire Signalisation et Transports Ioniques Membranaires, CNRS, Université de Poitiers, Poitiers, France
| | | | - Dominique Mottier
- Hôpital de la Cavale Blanche, CHRU Brest, Centre d'Investigation Clinique, INSERM CIC 1412, Brest, France
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19
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Stanley EF. PresyNaptic calcium channels: why is P selected before N? Biophys J 2015; 108:451-2. [PMID: 25650909 DOI: 10.1016/j.bpj.2014.12.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Elise F Stanley
- Toronto Western Research Institute, Toronto, Ontario, Canada.
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20
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Naranjo D, Wen H, Brehm P. Zebrafish CaV2.1 calcium channels are tailored for fast synchronous neuromuscular transmission. Biophys J 2015; 108:578-84. [PMID: 25650925 DOI: 10.1016/j.bpj.2014.11.3484] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 12/30/2022] Open
Abstract
The CaV2.2 (N-type) and CaV2.1 (P/Q-type) voltage-dependent calcium channels are prevalent throughout the nervous system where they mediate synaptic transmission, but the basis for the selective presence at individual synapses still remains an open question. The CaV2.1 channels have been proposed to respond more effectively to brief action potentials (APs), an idea supported by computational modeling. However, the side-by-side comparison of CaV2.1 and CaV2.2 kinetics in intact neurons failed to reveal differences. As an alternative means for direct functional comparison we expressed zebrafish CaV2.1 and CaV2.2 α-subunits, along with their accessory subunits, in HEK293 cells. HEK cells lack calcium currents, thereby circumventing the need for pharmacological inhibition of mixed calcium channel isoforms present in neurons. HEK cells also have a simplified morphology compared to neurons, which improves voltage control. Our measurements revealed faster kinetics and shallower voltage-dependence of activation and deactivation for CaV2.1. Additionally, recordings of calcium current in response to a command waveform based on the motorneuron AP show, directly, more effective activation of CaV2.1. Analysis of calcium currents associated with the AP waveform indicate an approximately fourfold greater open probability (PO) for CaV2.1. The efficient activation of CaV2.1 channels during APs may contribute to the highly reliable transmission at zebrafish neuromuscular junctions.
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Affiliation(s)
- David Naranjo
- Centro Interdisciplinario de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Hua Wen
- Oregon Health and Science University, Portland, Oregon
| | - Paul Brehm
- Oregon Health and Science University, Portland, Oregon.
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21
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Grigoryev PN, Zefirov AL. The Same Synaptic Vesicles Originate Synchronous and Asynchronous Transmitter Release. Acta Naturae 2015; 7:81-8. [PMID: 26483963 PMCID: PMC4610168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transmitter release and synaptic vesicle exo- and endocytosis during high-frequency stimulation (20 pulses/s) in the extracellular presence of different bivalent cations (Ca(2+), Sr2+ or Ba2+) were studied in frog cutaneous pectoris nerve-muscle preparations. It was shown in electrophysiological experiments that almost only synchronous transmitter release was registered in a Ca(2+)-containing solution; a high intensity of both synchronous and asynchronous transmitter release was registered in a Sr2+-containing solution, and asynchronous transmitter release almost only was observed in a Ba2+-containing solution. It was shown in experiments with a FM 1-43 fluorescent dye that the synaptic vesicles that undergo exocytosis-endocytosis during synchronous transmitter release (Ca-solutions) are able to participate in asynchronous exocytosis in Ba-solutions. The vesicles that had participated in the asynchronous transmitter release (Ba-solutions) could subsequently participate in a synchronous release (Ca-solutions). It was shown in experiments with isolated staining of recycling and reserve synaptic vesicle pools that both types of evoked transmitter release originate from the same synaptic vesicle pool.
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Affiliation(s)
- P. N. Grigoryev
- Kazan State Medical University, Ministry of Health of the Russian Federation, Butlerov Str., 49, Kazan, 420012, Russia
| | - A. L. Zefirov
- Kazan State Medical University, Ministry of Health of the Russian Federation, Butlerov Str., 49, Kazan, 420012, Russia
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22
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Carmean V, Yonkers MA, Tellez MB, Willer JR, Willer GB, Gregg RG, Geisler R, Neuhauss SC, Ribera AB. pigk Mutation underlies macho behavior and affects Rohon-Beard cell excitability. J Neurophysiol 2015; 114:1146-57. [PMID: 26133798 DOI: 10.1152/jn.00355.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/25/2015] [Indexed: 12/20/2022] Open
Abstract
The study of touch-evoked behavior allows investigation of both the cells and circuits that generate a response to tactile stimulation. We investigate a touch-insensitive zebrafish mutant, macho (maco), previously shown to have reduced sodium current amplitude and lack of action potential firing in sensory neurons. In the genomes of mutant but not wild-type embryos, we identify a mutation in the pigk gene. The encoded protein, PigK, functions in attachment of glycophosphatidylinositol anchors to precursor proteins. In wild-type embryos, pigk mRNA is present at times when mutant embryos display behavioral phenotypes. Consistent with the predicted loss of function induced by the mutation, knock-down of PigK phenocopies maco touch insensitivity and leads to reduced sodium current (INa) amplitudes in sensory neurons. We further test whether the genetic defect in pigk underlies the maco phenotype by overexpressing wild-type pigk in mutant embryos. We find that ubiquitous expression of wild-type pigk rescues the touch response in maco mutants. In addition, for maco mutants, expression of wild-type pigk restricted to sensory neurons rescues sodium current amplitudes and action potential firing in sensory neurons. However, expression of wild-type pigk limited to sensory cells of mutant embryos does not allow rescue of the behavioral touch response. Our results demonstrate an essential role for pigk in generation of the touch response beyond that required for maintenance of proper INa density and action potential firing in sensory neurons.
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Affiliation(s)
- V Carmean
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - M A Yonkers
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - M B Tellez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - J R Willer
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and
| | - G B Willer
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and
| | - R G Gregg
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and
| | - R Geisler
- Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
| | - S C Neuhauss
- Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
| | - A B Ribera
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
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23
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Zebrafish mutants of the neuromuscular junction: swimming in the gene pool. J Physiol Sci 2015; 65:217-21. [PMID: 25782439 PMCID: PMC4408355 DOI: 10.1007/s12576-015-0372-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 02/28/2015] [Indexed: 01/07/2023]
Abstract
This review provides an overview of zebrafish mutants with dysfunctional acetylcholine receptors or related proteins at the neuromuscular junction (NMJ). The NMJ, which has served as the classical model of the chemical synapse, uses acetylcholine as the neurotransmitter, and mutations of proteins involved in the signaling cascade lead to a variety of behavioral phenotypes. Mutants isolated after random chemical mutagenesis screening are summarized, and advances in the field resulting from these mutants are discussed.
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24
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Khalil HS, Mitev V, Vlaykova T, Cavicchi L, Zhelev N. Discovery and development of Seliciclib. How systems biology approaches can lead to better drug performance. J Biotechnol 2015; 202:40-9. [PMID: 25747275 DOI: 10.1016/j.jbiotec.2015.02.032] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 11/30/2022]
Abstract
Seliciclib (R-Roscovitine) was identified as an inhibitor of CDKs and has undergone drug development and clinical testing as an anticancer agent. In this review, the authors describe the discovery of Seliciclib and give a brief summary of the biology of the CDKs Seliciclib inhibits. An overview of the published in vitro and in vivo work supporting the development as an anti-cancer agent, from in vitro experiments to animal model studies ending with a summary of the clinical trial results and trials underway is presented. In addition some potential non-oncology applications are explored and the potential mode of action of Seliciclib in these areas is described. Finally the authors argue that optimisation of the therapeutic effects of kinase inhibitors such as Seliciclib could be enhanced using a systems biology approach involving mathematical modelling of the molecular pathways regulating cell growth and division.
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Affiliation(s)
- Hilal S Khalil
- CMCBR, SIMBIOS, School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, Scotland, UK
| | - Vanio Mitev
- Department of Chemistry and Biochemistry, Medical University of Sofia, 1431 Sofia, Bulgaria
| | - Tatyana Vlaykova
- Department of Chemistry and Biochemistry, Medical Faculty, Trakia University, Stara Zagora, Bulgaria
| | - Laura Cavicchi
- CMCBR, SIMBIOS, School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, Scotland, UK
| | - Nikolai Zhelev
- CMCBR, SIMBIOS, School of Science, Engineering and Technology, Abertay University, Dundee DD1 1HG, Scotland, UK.
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25
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A single mutation in the acetylcholine receptor δ-subunit causes distinct effects in two types of neuromuscular synapses. J Neurosci 2014; 34:10211-8. [PMID: 25080583 DOI: 10.1523/jneurosci.0426-14.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mutations in AChR subunits, expressed as pentamers in neuromuscular junctions (NMJs), cause various types of congenital myasthenic syndromes. In AChR pentamers, the adult ε subunit gradually replaces the embryonic γ subunit as the animal develops. Because of this switch in subunit composition, mutations in specific subunits result in synaptic phenotypes that change with developmental age. However, a mutation in any AChR subunit is considered to affect the NMJs of all muscle fibers equally. Here, we report a zebrafish mutant of the AChR δ subunit that exhibits two distinct NMJ phenotypes specific to two muscle fiber types: slow or fast. Homozygous fish harboring a point mutation in the δ subunit form functional AChRs in slow muscles, whereas receptors in fast muscles are nonfunctional. To test the hypothesis that different subunit compositions in slow and fast muscles underlie distinct phenotypes, we examined the presence of ε/γ subunits in NMJs using specific antibodies. Both wild-type and mutant larvae lacked ε/γ subunits in slow muscle synapses. These findings in zebrafish suggest that some mutations in human congenital myasthenic syndromes may affect slow and fast muscle fibers differently.
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26
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Wen H, Hubbard JM, Rakela B, Linhoff MW, Mandel G, Brehm P. Synchronous and asynchronous modes of synaptic transmission utilize different calcium sources. eLife 2013; 2:e01206. [PMID: 24368731 PMCID: PMC3869123 DOI: 10.7554/elife.01206] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/18/2013] [Indexed: 12/16/2022] Open
Abstract
Asynchronous transmission plays a prominent role at certain synapses but lacks the mechanistic insights of its synchronous counterpart. The current view posits that triggering of asynchronous release during repetitive stimulation involves expansion of the same calcium domains underlying synchronous transmission. In this study, live imaging and paired patch clamp recording at the zebrafish neuromuscular synapse reveal contributions by spatially distinct calcium sources. Synchronous release is tied to calcium entry into synaptic boutons via P/Q type calcium channels, whereas asynchronous release is boosted by a propagating intracellular calcium source initiated at off-synaptic locations in the axon and axonal branch points. This secondary calcium source fully accounts for the persistence following termination of the stimulus and sensitivity to slow calcium buffers reported for asynchronous release. The neuromuscular junction and CNS neurons share these features, raising the possibility that secondary calcium sources are common among synapses with prominent asynchronous release. DOI: http://dx.doi.org/10.7554/eLife.01206.001.
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Affiliation(s)
- Hua Wen
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jeffrey M Hubbard
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Benjamin Rakela
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Michael W Linhoff
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Gail Mandel
- Vollum Institute, Oregon Health and Science University, Portland, United States
- Howard Hughes Medical Institute, Oregon Health and Science University, Portland, United States
| | - Paul Brehm
- Vollum Institute, Oregon Health and Science University, Portland, United States
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