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Arcos-Hernández C, Nishigaki T. Ion currents through the voltage sensor domain of distinct families of proteins. J Biol Phys 2023; 49:393-413. [PMID: 37851173 PMCID: PMC10651576 DOI: 10.1007/s10867-023-09645-z] [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: 04/28/2023] [Accepted: 09/11/2023] [Indexed: 10/19/2023] Open
Abstract
The membrane potential of a cell (Vm) regulates several physiological processes. The voltage sensor domain (VSD) is a region that confers voltage sensitivity to different types of transmembrane proteins such as the following: voltage-gated ion channels, the voltage-sensing phosphatase (Ci-VSP), and the sperm-specific Na+/H+ exchanger (sNHE). VSDs contain four transmembrane segments (S1-S4) and several positively charged amino acids in S4, which are essential for the voltage sensitivity of the protein. Generally, in response to changes of the Vm, the positive residues of S4 displace along the plasma membrane without generating ionic currents through this domain. However, some native (e.g., Hv1 channel) and mutants of VSDs produce ionic currents. These gating pore currents are usually observed in VSDs that lack one or more of the conserved positively charged amino acids in S4. The gating pore currents can also be induced by the isolation of a VSD from the rest of the protein domains. In this review, we summarize gating pore currents from all families of proteins with VSDs with classification into three cases: (1) pathological, (2) physiological, and (3) artificial currents. We reinforce the model in which the position of S4 that lacks the positively charged amino acid determines the voltage dependency of the gating pore current of all VSDs independent of protein families.
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Affiliation(s)
- César Arcos-Hernández
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico.
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
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2
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Chattopadhayay S, Ghosh A, Kumar Mukhopadhyay T, Sharma R, Datta A, Talukdar P. Supramolecular Barrel-Rosette Ion Channel Based on 3,5-Diaminobenzoic Acid for Cation-Anion Symport. Angew Chem Int Ed Engl 2023; 62:e202313712. [PMID: 37732556 DOI: 10.1002/anie.202313712] [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: 09/14/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 09/22/2023]
Abstract
The structural tropology and functions of natural cation-anion symporting channels have been continuously investigated due to their crucial role in regulating various physiological functions. To understand the physiological functions of the natural symporter channels, it is vital to develop small-molecule-based biomimicking systems that can provide mechanistic insights into the ion-binding sites and the ion-translocation pathways. Herein, we report a series of bis((R)-(-)-mandelic acid)-linked 3,5-diaminobenzoic acid based self-assembled ion channels with distinctive ion transport ability. Ion transport experiment across the lipid bilayer membrane revealed that compound 1 b exhibits the highest transport activity among the series, and it has interesting selective co-transporting functions, i.e., facilitates K+ /ClO4 - symport. Electrophysiology experiments confirmed the formation of supramolecular ion channels with an average diameter of 6.2±1 Å and single channel conductance of 57.3±1.9 pS. Selectivity studies of channel 1 b in a bilayer lipid membrane demonstrated a permeability ratio ofP C l - / P K + = 0 . 053 ± 0 . 02 ${{P}_{{Cl}^{-}}/{P}_{{K}^{+}}=0.053\pm 0.02}$ ,P C l O 4 - / P C l - = 2 . 1 ± 0 . 5 ${{P}_{{ClO}_{4}^{-}}/{P}_{{Cl}^{-}}=2.1\pm 0.5}$ , andP K + / P N a + = 1 . 5 ± 1 , ${{P}_{{K}^{+}}/{P}_{{Na}^{+}}=1.5\pm 1,}$ indicating the higher selectivity of the channel towards KClO4 over KCl salt. A hexameric assembly of a trimeric rosette of 1 b was subjected to molecular dynamics simulations with different salts to understand the supramolecular channel formation and ion selectivity pattern.
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Affiliation(s)
- Sandip Chattopadhayay
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, 411008, Pune, Maharashtra, India
| | - Anupam Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Raja Subodh Chandra Mallick Road, Jadavpur, 700032, Kolkata, West Bengal, India
| | - Titas Kumar Mukhopadhyay
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Raja Subodh Chandra Mallick Road, Jadavpur, 700032, Kolkata, West Bengal, India
| | - Rashmi Sharma
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, 411008, Pune, Maharashtra, India
| | - Ayan Datta
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Raja Subodh Chandra Mallick Road, Jadavpur, 700032, Kolkata, West Bengal, India
| | - Pinaki Talukdar
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, 411008, Pune, Maharashtra, India
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Mortensen M, Xu Y, Shehata MA, Krall J, Ernst M, Frølund B, Smart TG. Pregnenolone sulfate analogues differentially modulate GABA A receptor closed/desensitised states. Br J Pharmacol 2023; 180:2482-2499. [PMID: 37194503 PMCID: PMC10952582 DOI: 10.1111/bph.16143] [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: 06/07/2021] [Revised: 02/07/2023] [Accepted: 05/05/2023] [Indexed: 05/18/2023] Open
Abstract
BACKGROUND AND PURPOSE GABAA receptors are regulated by numerous classes of allosteric modulators. However, regulation of receptor macroscopic desensitisation remains largely unexplored and may offer new therapeutic opportunities. Here, we report the emerging potential for modulating desensitisation with analogues of the endogenous inhibitory neurosteroid, pregnenolone sulfate. EXPERIMENTAL APPROACH New pregnenolone sulfate analogues were synthesised incorporating various heterocyclic substitutions located at the C-21 position on ring D. The pharmacological profiles of these compounds were assessed using electrophysiology and recombinant GABAA receptors together with mutagenesis, molecular dynamics simulations, structural modelling and kinetic simulations. KEY RESULTS All seven analogues retained a negative allosteric modulatory capability whilst exhibiting diverse potencies. Interestingly, we observed differential effects on GABA current decay by compounds incorporating either a six- (compound 5) or five-membered heterocyclic ring (compound 6) on C-21, which was independent of their potencies as inhibitors. We propose that differences in molecular charges, and the targeted binding of analogues to specific states of the GABAA receptor, are the most likely cause of the distinctive functional profiles. CONCLUSIONS AND IMPLICATIONS Our findings reveal that heterocyclic addition to inhibitory neurosteroids not only affected their potency and macroscopic efficacy but also affected innate receptor mechanisms that underlie desensitisation. Acute modulation of macroscopic desensitisation will determine the degree and duration of GABA inhibition, which are vital for the integration of neural circuit activity. Discovery of this form of modulation could present an opportunity for next-generation GABAA receptor drug design and development.
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Affiliation(s)
- Martin Mortensen
- Department of Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUK
| | - Yue Xu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Mohamed A. Shehata
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Present address:
Xellia Pharmaceuticals ApSCopenhagenDenmark
| | - Margot Ernst
- Department of Pathology of the Nervous System, Center for Brain ResearchMedical University of ViennaViennaAustria
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Trevor G. Smart
- Department of Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUK
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Koch NA, Sonnenberg L, Hedrich UBS, Lauxmann S, Benda J. Loss or gain of function? Effects of ion channel mutations on neuronal firing depend on the neuron type. Front Neurol 2023; 14:1194811. [PMID: 37292138 PMCID: PMC10244640 DOI: 10.3389/fneur.2023.1194811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Introduction Clinically relevant mutations to voltage-gated ion channels, called channelopathies, alter ion channel function, properties of ionic currents, and neuronal firing. The effects of ion channel mutations are routinely assessed and characterized as loss of function (LOF) or gain of function (GOF) at the level of ionic currents. However, emerging personalized medicine approaches based on LOF/GOF characterization have limited therapeutic success. Potential reasons are among others that the translation from this binary characterization to neuronal firing is currently not well-understood-especially when considering different neuronal cell types. In this study, we investigate the impact of neuronal cell type on the firing outcome of ion channel mutations. Methods To this end, we simulated a diverse collection of single-compartment, conductance-based neuron models that differed in their composition of ionic currents. We systematically analyzed the effects of changes in ion current properties on firing in different neuronal types. Additionally, we simulated the effects of known mutations in KCNA1 gene encoding the KV1.1 potassium channel subtype associated with episodic ataxia type 1 (EA1). Results These simulations revealed that the outcome of a given change in ion channel properties on neuronal excitability depends on neuron type, i.e., the properties and expression levels of the unaffected ionic currents. Discussion Consequently, neuron-type specific effects are vital to a full understanding of the effects of channelopathies on neuronal excitability and are an important step toward improving the efficacy and precision of personalized medicine approaches.
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Affiliation(s)
- Nils A. Koch
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Ulrike B. S. Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stephan Lauxmann
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jan Benda
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
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Mohammed SR, Gafoor S, Panday A. Acute myotonic reaction during succinylcholine anaesthesia. Pract Neurol 2023; 23:74-77. [PMID: 36192135 DOI: 10.1136/pn-2022-003352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2022] [Indexed: 02/02/2023]
Abstract
A 21-year-old woman developed an acute myotonic reaction while undergoing anaesthesia using succinylcholine. Examination later showed she had shoulder, neck and calf hypertrophy, bilateral symmetrical ptosis and eyelid, handgrip and percussion myotonia. Peripheral neurophysiology studies identified significant, continuous myotonic discharges in both upper and lower limbs. Genetic analysis identified a c.3917G>A (p.Gly1306Glu) mutation in the SCN4A gene, confirming a diagnosis of sodium channel myotonia. Succinylcholine and other depolarising agents can precipitate life-threatening acute myotonic reactions when given to patients with myotonia. Patients with neuromuscular disorders are at an increased risk of perioperative anaesthetic complications. We report a woman who developed an acute myotonic reaction whilst undergoing anaesthesia, in the context of an unrecognised myotonic disorder. We then discuss an approach to the diagnosis of myotonic disorders.
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Affiliation(s)
- Saeed Rashaad Mohammed
- Department of Clinical Medical Sciences, The University of the West Indies at St Augustine Faculty of Medical Sciences, St Augustine, Trinidad and Tobago
| | - Stefan Gafoor
- Department of Medicine, Eric Williams Medical Sciences Complex Compound, Champ Fleurs, Trinidad and Tobago
| | - Avidesh Panday
- Department of Clinical Medical Sciences, The University of the West Indies at St Augustine Faculty of Medical Sciences, St Augustine, Trinidad and Tobago
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GluR2Q and GluR2R AMPA Subunits are not Targets of lypd2 Interaction. PLoS One 2022; 17:e0278278. [PMID: 36441793 PMCID: PMC9704558 DOI: 10.1371/journal.pone.0278278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/12/2022] [Indexed: 11/30/2022] Open
Abstract
A large family of prototoxin-like molecules endogenous to mammals, Ly6 proteins have been implicated in the regulation of cell signaling processes across multiple species. Previous work has shown that certain members of the Ly6 family are expressed in the brain and target nicotinic acetylcholine receptor and potassium channel function. Structural similarities between Ly6 proteins and alpha-neurotoxins suggest the possibility of additional ionotropic receptor targets. Here, we investigated the possibility of lypd2 as a novel regulator of AMPA receptor (AMPAR) function. In particular, we focused on potential interactions with the Q/R isoforms of the GluR2 subunit, which have profound impacts on AMPAR permeability to calcium during neuronal stimulation. We find that although lypd2 and GluR2 share overlapping expression patterns in the mouse hippocampus, there was no interaction between lypd2 and either GluR2Q or GluR2R isoform. These results underscore the importance of continuing to investigate novel targets for Ly6 interaction and regulation.
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Cancer as a Channelopathy—Appreciation of Complimentary Pathways Provides a Different Perspective for Developing Treatments. Cancers (Basel) 2022; 14:cancers14194627. [PMID: 36230549 PMCID: PMC9562872 DOI: 10.3390/cancers14194627] [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: 07/26/2022] [Revised: 09/17/2022] [Accepted: 09/21/2022] [Indexed: 12/15/2022] Open
Abstract
Simple Summary While improvements in technology have improved our ability to treat many forms of cancer when diagnosed at an early stage of the disease, the ability to improve survival and quality of life for patients with late stage disease has been limited, largely due to the ability of cancer cells to evade destruction when treatments block preferred paths for survival. Here, we review the role that ions and ion channels play in normal cell function, the development of disease and their role in the life and death of a cell. It is hoped that viewing cancer from the perspective of altered ion channel expression and ion balance may provide a novel approach for developing more effective treatments for this devastating disease. Abstract Life depends upon the ability of cells to evaluate and adapt to a constantly changing environment and to maintain internal stability to allow essential biochemical reactions to occur. Ions and ion channels play a crucial role in this process and are essential for survival. Alterations in the expression of the transmembrane proteins responsible for maintaining ion balance that occur as a result of mutations in the genetic code or in response to iatrogenically induced changes in the extracellular environment is a characteristic feature of oncogenesis and identifies cancer as one of a constellation of diseases known as channelopathies. The classification of cancer as a channelopathy provides a different perspective for viewing the disease. Potentially, it may expand opportunities for developing novel ways to affect or reverse the deleterious changes that underlie establishing and sustaining disease and developing tolerance to therapeutic attempts at treatment. The role of ions and ion channels and their interactions in the cell’s ability to maintain ionic balance, homeostasis, and survival are reviewed and possible approaches that mitigate gain or loss of ion channel function to contribute to new or enhance existing cancer therapies are discussed.
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Chen XY, Chen L, Yang W, Xie AM. GLP-1 Suppresses Feeding Behaviors and Modulates Neuronal Electrophysiological Properties in Multiple Brain Regions. Front Mol Neurosci 2022; 14:793004. [PMID: 34975402 PMCID: PMC8718614 DOI: 10.3389/fnmol.2021.793004] [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: 10/11/2021] [Accepted: 11/29/2021] [Indexed: 11/24/2022] Open
Abstract
The glucagon-like peptide-1 (GLP-1) plays important roles in the regulation of food intake and energy metabolism. Peripheral or central GLP-1 suppresses food intake and reduces body weight. The electrophysiological properties of neurons in the mammalian central nervous system reflect the neuronal excitability and the functional organization of the brain. Recent studies focus on elucidating GLP-1-induced suppression of feeding behaviors and modulation of neuronal electrophysiological properties in several brain regions. Here, we summarize that activation of GLP-1 receptor (GLP-1R) suppresses food intake and induces postsynaptic depolarization of membrane potential and/or presynaptic modulation of glutamatergic or GABAergic neurotransmission in brain nuclei located within the medulla oblongata, pons, mesencephalon, diencephalon, and telencephalon. This review may provide a background to guide future research about the cellular mechanisms of GLP-1-induced feeding inhibition.
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Affiliation(s)
- Xin-Yi Chen
- Department of International Medicine, Affiliated Hospital of Qingdao University, Qingdao, China.,Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Lei Chen
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Wu Yang
- Department of International Medicine, Affiliated Hospital of Qingdao University, Qingdao, China
| | - An-Mu Xie
- Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
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9
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Sampson B, Hammers J, Stram M. Forensic aspects of cardiovascular pathology. Cardiovasc Pathol 2022. [DOI: 10.1016/b978-0-12-822224-9.00003-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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10
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Gabriel TS, Hansen UP, Urban M, Drexler N, Winterstein T, Rauh O, Thiel G, Kast SM, Schroeder I. Asymmetric Interplay Between K + and Blocker and Atomistic Parameters From Physiological Experiments Quantify K + Channel Blocker Release. Front Physiol 2021; 12:737834. [PMID: 34777005 PMCID: PMC8586521 DOI: 10.3389/fphys.2021.737834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/04/2021] [Indexed: 11/23/2022] Open
Abstract
Modulating the activity of ion channels by blockers yields information on both the mode of drug action and on the biophysics of ion transport. Here we investigate the interplay between ions in the selectivity filter (SF) of K+ channels and the release kinetics of the blocker tetrapropylammonium in the model channel KcvNTS. A quantitative expression calculates blocker release rate constants directly from voltage-dependent ion occupation probabilities in the SF. The latter are obtained by a kinetic model of single-channel currents recorded in the absence of the blocker. The resulting model contains only two adjustable parameters of ion-blocker interaction and holds for both symmetric and asymmetric ionic conditions. This data-derived model is corroborated by 3D reference interaction site model (3D RISM) calculations on several model systems, which show that the K+ occupation probability is unaffected by the blocker, a direct consequence of the strength of the ion-carbonyl attraction in the SF, independent of the specific protein background. Hence, KcvNTS channel blocker release kinetics can be reduced to a small number of system-specific parameters. The pore-independent asymmetric interplay between K+ and blocker ions potentially allows for generalizing these results to similar potassium channels.
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Affiliation(s)
- Tobias S Gabriel
- Plant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Ulf-Peter Hansen
- Department of Structural Biology, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Martin Urban
- Physikalische Chemie III, Technische Universita̋t Dortmund, Dortmund, Germany
| | - Nils Drexler
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University Jena, Jena, Germany
| | - Tobias Winterstein
- Plant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Oliver Rauh
- Plant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Gerhard Thiel
- Plant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Stefan M Kast
- Physikalische Chemie III, Technische Universita̋t Dortmund, Dortmund, Germany
| | - Indra Schroeder
- Plant Membrane Biophysics, Technische Universität Darmstadt, Darmstadt, Germany.,Institute of Physiology II, University Hospital Jena, Friedrich Schiller University Jena, Jena, Germany
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Navas P, Cascajo MV, Alcázar-Fabra M, Hernández-Camacho JD, Sánchez-Cuesta A, Rodríguez ABC, Ballesteros-Simarro M, Arroyo-Luque A, Rodríguez-Aguilera JC, Fernández-Ayala DJM, Brea-Calvo G, López-Lluch G, Santos-Ocaña C. Secondary CoQ 10 deficiency, bioenergetics unbalance in disease and aging. Biofactors 2021; 47:551-569. [PMID: 33878238 DOI: 10.1002/biof.1733] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/24/2021] [Indexed: 12/21/2022]
Abstract
Coenzyme Q10 (CoQ10 ) deficiency is a rare disease characterized by a decreased accumulation of CoQ10 in cell membranes. Considering that CoQ10 synthesis and most of its functions are carried out in mitochondria, CoQ10 deficiency cases are usually considered a mitochondrial disease. A relevant feature of CoQ10 deficiency is that it is the only mitochondrial disease with a successful therapy available, the CoQ10 supplementation. Defects in components of the synthesis machinery caused by mutations in COQ genes generate the primary deficiency of CoQ10 . Mutations in genes that are not directly related to the synthesis machinery cause secondary deficiency. Cases of CoQ10 deficiency without genetic origin are also considered a secondary deficiency. Both types of deficiency can lead to similar clinical manifestations, but the knowledge about primary deficiency is deeper than secondary. However, secondary deficiency cases may be underestimated since many of their clinical manifestations are shared with other pathologies. This review shows the current state of secondary CoQ10 deficiency, which could be even more relevant than primary deficiency for clinical activity. The analysis covers the fundamental features of CoQ10 deficiency, which are necessary to understand the biological and clinical differences between primary and secondary CoQ10 deficiencies. Further, a more in-depth analysis of CoQ10 secondary deficiency was undertaken to consider its origins, introduce a new way of classification, and include aging as a form of secondary deficiency.
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Affiliation(s)
- Plácido Navas
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - María V Cascajo
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - María Alcázar-Fabra
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Juan D Hernández-Camacho
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Sánchez-Cuesta
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Belén Cortés Rodríguez
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
- Laboratorio de Fisiopatología Celular y Bioenergética, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
| | - Manuel Ballesteros-Simarro
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio Arroyo-Luque
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Carlos Rodríguez-Aguilera
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
- Laboratorio de Fisiopatología Celular y Bioenergética, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
| | - Daniel J M Fernández-Ayala
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Gloria Brea-Calvo
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Guillermo López-Lluch
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
| | - Carlos Santos-Ocaña
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA, Sevilla, Spain
- CIBERER, Instituto de Salud Carlos III, Madrid, Spain
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Nastou KC, Batskinis MA, Litou ZI, Hamodrakas SJ, Iconomidou VA. Analysis of Single-Nucleotide Polymorphisms in Human Voltage-Gated Ion Channels. J Proteome Res 2019; 18:2310-2320. [DOI: 10.1021/acs.jproteome.9b00121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katerina C. Nastou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Michail A. Batskinis
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Zoi I. Litou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Stavros J. Hamodrakas
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Vassiliki A. Iconomidou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
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13
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Raghavan M, Fee D, Barkhaus PE. Generation and propagation of the action potential. ACTA ACUST UNITED AC 2019; 160:3-22. [DOI: 10.1016/b978-0-444-64032-1.00001-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Boufroura H, Poyer S, Gaucher A, Huin C, Salpin JY, Clavier G, Prim D. Topology and Electronic Density Driven Generation of Alkali Cation Complexes. Chemistry 2018; 24:8656-8663. [PMID: 29577466 DOI: 10.1002/chem.201800707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Indexed: 01/25/2023]
Abstract
The formation and characterization of K+ and Cs+ complexes originating from the cooperativity of three non-covalent interactions is explored. The tridimensional preorganization of the naphthothiophene platform displays a favorable well-defined bay region combining a π fragment and a carbonyl moiety flanking a central sulfur atom. A joint theoretical and experimental infrared multiple photon dissociation (IRMPD) study allowed deciphering the key contribution of the orthogonal phenyl fragment to the elaboration of alkali metal complexes. In combination with S and CO interactions, the π-cation interaction significantly enhances the binding energies of naphthothiophene derivatives.
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Affiliation(s)
- Hamza Boufroura
- ILV, UVSQ, CNRS, Université Paris-Saclay, 78035, Versailles, France
| | - Salomé Poyer
- LAMBE, Univ Evry, CNRS, CEA, Université Paris-Saclay, 91025, Evry, France.,LAMBE, U-Cergy, Université Paris-Seine, 91025, Evry, France
| | - Anne Gaucher
- ILV, UVSQ, CNRS, Université Paris-Saclay, 78035, Versailles, France
| | - Cécile Huin
- LAMBE, Univ Evry, CNRS, CEA, Université Paris-Saclay, 91025, Evry, France.,LAMBE, U-Cergy, Université Paris-Seine, 91025, Evry, France
| | - Jean-Yves Salpin
- LAMBE, Univ Evry, CNRS, CEA, Université Paris-Saclay, 91025, Evry, France.,LAMBE, U-Cergy, Université Paris-Seine, 91025, Evry, France
| | - Gilles Clavier
- PPSM, ENS Cachan, CNRS, Université Paris-Saclay, 94235, Cachan, France
| | - Damien Prim
- ILV, UVSQ, CNRS, Université Paris-Saclay, 78035, Versailles, France
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15
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Moreels L, Peigneur S, Yamaguchi Y, Vriens K, Waelkens E, Zhu S, Thevissen K, Cammue BPA, Sato K, Tytgat J. Expanding the pharmacological profile of κ-hefutoxin 1 and analogues: A focus on the inhibitory effect on the oncogenic channel K v10.1. Peptides 2017; 98:43-50. [PMID: 27578329 DOI: 10.1016/j.peptides.2016.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/21/2016] [Accepted: 08/23/2016] [Indexed: 10/21/2022]
Abstract
Peptide toxins, such as scorpion peptides, are interesting lead compounds in the search for novel drugs. In this paper, the focus is on the scorpion peptide κ-hefutoxin 1. This peptide displays a cysteine-stabilized helix-loop-helix fold (CSα/α) and is known to be a weak Kv1.x inhibitor. Due to the low affinity of κ-hefutoxin 1 for these channels, it is assumed that the main target(s) of κ-hefutoxin 1 remain(s) unknown. In order to identify novel targets, electrophysiological measurements and antifungal assays were performed. The effect of κ-hefutoxin 1 was previously evaluated on a panel of 11 different voltage-gated potassium channels. Here, we extended this target screening with the oncogenic potassium channel Kv10.1. κ-Hefutoxin 1 was able to inhibit this channel in a dose-dependent manner (IC50∼26μM). Although the affinity is rather low, this is the first peptide toxin ever described to be a Kv10.1 inhibitor. The structure-activity relationship of κ-hefutoxin 1 on Kv10.1 was investigated by testing eight κ-hefutoxin 1 variants using the two-electrode voltage clamp technique. Several important amino acid residues were identified; the functional dyad residues (Tyr5 and Lys19), N-terminal residues (Gly1 and His2) and the amidated C-terminal residue (Cys22). Since the CSα/α fold is also found in a class of antifungal plant peptides, the α-hairpinines, we investigated the antifungal activity of κ-hefutoxin 1. κ-Hefutoxin 1 showed low activity against the plant pathogen Fusarium culmorum and no activity against three other yeast and fungal species, even at high concentrations (∼100μM).
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Affiliation(s)
- Lien Moreels
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg O&N2, Herestraat 49, PO Box 922, 3000 Leuven, Belgium.
| | - Steve Peigneur
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg O&N2, Herestraat 49, PO Box 922, 3000 Leuven, Belgium.
| | - Yoko Yamaguchi
- Department of Environmental Science, Fukuoka Women's University, Fukuoka 813-8529, Japan.
| | - Kim Vriens
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, PO Box 2460, 3001 Leuven, Belgium.
| | - Etienne Waelkens
- Laboratory of Protein Phosphorylation and Proteomics, KU Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, PO Box 901, 3000 Leuven, Belgium.
| | - Shunyi Zhu
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
| | - Karin Thevissen
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, PO Box 2460, 3001 Leuven, Belgium.
| | - Bruno P A Cammue
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, PO Box 2460, 3001 Leuven, Belgium; VIB Department of Plant Systems Biology, Technologiepark 927, 9052 Ghent, Belgium.
| | - Kazuki Sato
- Department of Environmental Science, Fukuoka Women's University, Fukuoka 813-8529, Japan.
| | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg O&N2, Herestraat 49, PO Box 922, 3000 Leuven, Belgium.
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16
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Aleman M, Finno CJ, Weich K, Penedo MCT. Investigation of Known Genetic Mutations of Arabian Horses in Egyptian Arabian Foals with Juvenile Idiopathic Epilepsy. J Vet Intern Med 2017; 32:465-468. [PMID: 29171123 PMCID: PMC5787150 DOI: 10.1111/jvim.14873] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/22/2017] [Accepted: 10/12/2017] [Indexed: 12/18/2022] Open
Abstract
Background The carrier status of lavender foal syndrome (LFS), cerebellar abiotrophy (CA), severe combined immunodeficiency (SCID), and occipitoatlantoaxial malformation (OAAM1) in foals with juvenile idiopathic epilepsy (JIE) is unknown. Hypothesis/Objectives To determine the carrier status of LFS, CA, SCID, and OAAM1 in foals with JIE. Animals Ten foals with JIE. Materials and Methods Archived DNA samples were tested for known genetic mutations causing LFS, CA, SCID, and OAAM1. The inclusion criteria consisted of having been diagnosed with JIE by ruling out other causes of seizures in foals and supported by electroencephalographic examination. Results Ten Egyptian Arabian horses (5 females and 5 males) were phenotyped as foals with JIE by electroencephalography (EEG). All foals were negative for the genetic mutations that cause LFS, CA, SCID, and OAAM1 except for 1 foal that was a carrier of CA. Conclusions and Clinical Importance Juvenile idiopathic epilepsy of Egyptian Arabian foals and LFS appear to be phenotypically and genetically distinct disorders. There was no apparent association between JIE and LFS, CA, SCID, and OAAM1.
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Affiliation(s)
- M Aleman
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA
| | - C J Finno
- School of Veterinary Medicine, Population Health and Reproduction, University of California Davis, Davis, CA
| | - K Weich
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA
| | - M C T Penedo
- School of Veterinary Medicine, Veterinary Genetics Laboratory, University of California Davis, Davis, CA
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17
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Transcriptomic correlates of neuron electrophysiological diversity. PLoS Comput Biol 2017; 13:e1005814. [PMID: 29069078 PMCID: PMC5673240 DOI: 10.1371/journal.pcbi.1005814] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 11/06/2017] [Accepted: 10/09/2017] [Indexed: 12/19/2022] Open
Abstract
How neuronal diversity emerges from complex patterns of gene expression remains poorly understood. Here we present an approach to understand electrophysiological diversity through gene expression by integrating pooled- and single-cell transcriptomics with intracellular electrophysiology. Using neuroinformatics methods, we compiled a brain-wide dataset of 34 neuron types with paired gene expression and intrinsic electrophysiological features from publically accessible sources, the largest such collection to date. We identified 420 genes whose expression levels significantly correlated with variability in one or more of 11 physiological parameters. We next trained statistical models to infer cellular features from multivariate gene expression patterns. Such models were predictive of gene-electrophysiological relationships in an independent collection of 12 visual cortex cell types from the Allen Institute, suggesting that these correlations might reflect general principles relating expression patterns to phenotypic diversity across very different cell types. Many associations reported here have the potential to provide new insights into how neurons generate functional diversity, and correlations of ion channel genes like Gabrd and Scn1a (Nav1.1) with resting potential and spiking frequency are consistent with known causal mechanisms. Our work highlights the promise and inherent challenges in using cell type-specific transcriptomics to understand the mechanistic origins of neuronal diversity.
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Differential Somatic Ca2+ Channel Profile in Midbrain Dopaminergic Neurons. J Neurosci 2017; 36:7234-45. [PMID: 27383597 DOI: 10.1523/jneurosci.0459-16.2016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/31/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Dopaminergic (DA) neurons located in the ventral midbrain continuously generate a slow endogenous pacemaker activity, the mechanism of which is still debated. It has been suggested that, in the substantia nigra pars compacta (SNc), the pacemaking relies more on Ca(2+) channels and that the density of L-type Ca(2+) channels is higher in these DA neurons than in those located in the ventral tegmental area (VTA). This might lead to a higher Ca(2+) load in SNc DA neurons and explain their higher susceptibility to degeneration. However, direct evidence for this hypothesis is lacking. We found that the L-type current and channel density are indeed higher in the somata of rat SNc DA neurons and that this current undergoes less inactivation in this region. Nonstationary fluctuation analysis measurements showed a much higher number of L-type channels in the soma of SNc DA neurons, as well as a smaller single-channel conductance, pointing to a possible different molecular identity of L-type channels in DA neurons from the two areas. A major consequence of this is that pacemaking and, even more so, bursting are associated with a larger Ca(2+) entry through L-type channels in SNc DA neurons than in their VTA counterparts. Our results establish a molecular and functional difference between two populations of midbrain DA neurons that may contribute to their differential sensitivity to neurodegeneration. SIGNIFICANCE STATEMENT Dopamine neurons from the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) are involved in various brain functions, such as movement initiation and goal directed behavior, respectively. This work shows that, although both neurons fire in a similar regular and slow pacemaker mode, this firing activity is supported by different calcium channel landscapes. Indeed, the L-type calcium current is larger in the soma of dopamine neurons of the SNc, leading to a higher charge transfer through L-type channels during pacemaking and bursting. Therefore, these neurons may be physiologically exposed to a larger stress than their neighbors from the VTA.
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19
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Schroeder I. How to resolve microsecond current fluctuations in single ion channels: the power of beta distributions. Channels (Austin) 2016; 9:262-80. [PMID: 26368656 DOI: 10.1080/19336950.2015.1083660] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A main ingredient for the understanding of structure/function correlates of ion channels is the quantitative description of single-channel gating and conductance. However, a wealth of information provided from fast current fluctuations beyond the temporal resolution of the recording system is often ignored, even though it is close to the time window accessible to molecular dynamics simulations. This kind of current fluctuations provide a special technical challenge, because individual opening/closing or blocking/unblocking events cannot be resolved, and the resulting averaging over undetected events decreases the single-channel current. Here, I briefly summarize the history of fast-current fluctuation analysis and focus on the so-called "beta distributions." This tool exploits characteristics of current fluctuation-induced excess noise on the current amplitude histograms to reconstruct the true single-channel current and kinetic parameters. A guideline for the analysis and recent applications demonstrate that a construction of theoretical beta distributions by Markov Model simulations offers maximum flexibility as compared to analytical solutions.
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Affiliation(s)
- Indra Schroeder
- a Plant Membrane Biophysics, Technical University of Darmstadt ; Darmstadt , Germany
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20
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Leon Guerrero CR, Pathak S, Grange DK, Singh GK, Nichols CG, Lee JM, Vo KD. Neurologic and neuroimaging manifestations of Cantú syndrome: A case series. Neurology 2016; 87:270-6. [PMID: 27316244 DOI: 10.1212/wnl.0000000000002861] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/11/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To describe the neurologic and neuroimaging manifestations associated with Cantú syndrome. METHODS We evaluated 10 patients with genetically confirmed Cantú syndrome. All adult patients, and pediatric patients who were able to cooperate and complete the studies, underwent neuroimaging, including vascular imaging. A salient neurologic history and examination was obtained for all patients. RESULTS We observed diffusely dilated and tortuous cerebral blood vessels in all patients who underwent vascular imaging. White matter changes were observed in all patients who completed an MRI brain study. Two patients had a persistent trigeminal artery. One patient had an occluded right middle cerebral artery. One patient had transient white matter changes suggestive of posterior reversible encephalopathic syndrome. Four patients had migraines with one patient having complicated migraines. Seizures were seen in early life but infrequent. The majority of patients had mild developmental delays and one patient had a diagnosis of autism. CONCLUSIONS Cantú syndrome is associated with various neurologic manifestations, particularly cerebrovascular findings including dilated and tortuous cerebral vessels, white matter changes, and persistent fetal circulation. Involvement of the KATP SUR2/Kir6.1 subtype potentially plays an important role in the neurologic manifestations of Cantú syndrome.
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Affiliation(s)
- Christopher R Leon Guerrero
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO
| | - Sheel Pathak
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO
| | - Dorothy K Grange
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO
| | - Gautam K Singh
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO
| | - Colin G Nichols
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO
| | - Jin-Moo Lee
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO.
| | - Katie D Vo
- From George Washington University (C.R.L.G.), Washington, DC; and Washington University School of Medicine (S.P., D.K.G., G.K.S., C.G.N., J.-M.L., K.D.V.), St. Louis, MO.
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21
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Sampson B, Hammers J. Forensic Aspects of Cardiovascular Pathology. Cardiovasc Pathol 2016. [DOI: 10.1016/b978-0-12-420219-1.00020-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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22
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Marioni-Henry K, Rusbridge C, Volk HA. Clinical Features in Border Terrier Dogs with Paroxysmal Involuntary Movements. Mov Disord Clin Pract 2015; 3:73-79. [PMID: 30713898 DOI: 10.1002/mdc3.12232] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 07/01/2015] [Accepted: 07/07/2015] [Indexed: 11/06/2022] Open
Abstract
Background There have been anecdotal reports of episodic involuntary movements in the Border Terrier dog breed for over a decade. Recently, it has been hypothesized that this condition may be a form of paroxysmal dystonic choreoathetosis. The aim of this study was to characterize the phenomenology and clinical course of this condition and compare it to known human movement disorders. Methods Data were collected retrospectively from clinical cases treated by veterinary neurologists and additional information was collected prospectively with an ad-hoc online survey directed to owners of affected dogs. Results The episodes are characterized by generalized dystonia, tremors, titubation, and, in some cases, autonomic signs, such as salivation and vomiting. The median age at onset of the episodes was 3 years and the interval between clusters of episodes could last several months. Most of the episodes occurred from rest, and 67% of the owners reported that the episodes were associated with a trigger, most often excitement. Some owners reported an improvement after changing their dog's diet. We hypothesize that the Border Terrier attacks represent a form of paroxysmal nonkinesigenic dyskinesia. Conclusions The finding of a dystonia phenotype within an inbred population suggests a genetic predisposition, and elucidating the genetic cause could facilitate improved understanding of dystonia. This genetic predisposition and the effect of treatment with anticonvulsant drugs and dietary changes on the severity of the paroxysms warrant further investigation on this condition.
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Affiliation(s)
- Katia Marioni-Henry
- Royal (Dick) School of Veterinary Studies Hospital for Small Animals, Veterinary Center The University of Edinburgh Roslin United Kingdom
| | - Clare Rusbridge
- Fitzpatrick Referrals Godalming United Kingdom.,School of Veterinary Medicine Faculty of Health & Medical Sciences University of Surrey Guildford United Kingdom
| | - Holger A Volk
- Department of Clinical Science and Services Royal Veterinary College Hatfield United Kingdom
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Roseti C, van Vliet EA, Cifelli P, Ruffolo G, Baayen JC, Di Castro MA, Bertollini C, Limatola C, Aronica E, Vezzani A, Palma E. GABAA currents are decreased by IL-1β in epileptogenic tissue of patients with temporal lobe epilepsy: implications for ictogenesis. Neurobiol Dis 2015; 82:311-320. [PMID: 26168875 DOI: 10.1016/j.nbd.2015.07.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/02/2015] [Accepted: 07/06/2015] [Indexed: 01/01/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is the most prevalent form of adult focal onset epilepsy often associated with drug-resistant seizures. Numerous studies suggest that neuroinflammatory processes are pathologic hallmarks of both experimental and human epilepsy. In particular, the interleukin (IL)-1β/IL-1 receptor type 1 (R1) axis is activated in epileptogenic tissue, where it contributes significantly to the generation and recurrence of seizures in animal models. In this study, we investigated whether IL-1β affects the GABA-evoked currents (I(GABA)) in TLE tissue from humans. Given the limited availability of fresh human brain specimens, we used the "microtransplantation" method of injecting Xenopus oocytes with membranes from surgically resected hippocampal and cortical tissue from 21 patients with TLE and hippocampal sclerosis (HS), hippocampal tissue from five patients with TLE without HS, and autoptic and surgical brain specimens from 15 controls without epilepsy. We report the novel finding that pathophysiological concentrations of IL-1β decreased the I(GABA) amplitude by up to 30% in specimens from patients with TLE with or without HS, but not in control tissues. This effect was reproduced by patch-clamp recordings on neurons in entorhinal cortex slices from rats with chronic epilepsy, and was not observed in control slices. In TLE specimens from humans, the IL-1β effect was mediated by IL-1R1 and PKC. We also showed that IL-1R1 and IRAK1, the proximal kinase mediating the IL-1R1 signaling, are both up-regulated in the TLE compared with control specimens, thus supporting the idea that the IL-1β/IL-R1 axis is activated in human epilepsy. Our findings suggest a novel mechanism possibly underlying the ictogenic action of IL-1β, thus suggesting that this cytokine contributes to seizure generation in human TLE by reducing GABA-mediated neurotransmission.
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Affiliation(s)
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Pierangelo Cifelli
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy; Ri.MED Foundation, Palermo, Italy
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Johannes C Baayen
- Department of Neurosurgery, VU University Medical Center, Amsterdam, The Netherlands
| | - Maria Amalia Di Castro
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Cristina Bertollini
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN-Heemstede), The Netherlands
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy.
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy; IRCCS San Raffaele Pisana, Rome, Italy.
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Li J, Huang Q, Ge L, Xu J, Shi X, Xie W, Liu X, Liu X. Identification of genetic variations of a Chinese family with paramyotonia congenita via whole exome sequencing. GENOMICS DATA 2015; 4:65-8. [PMID: 26484179 PMCID: PMC4535863 DOI: 10.1016/j.gdata.2015.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 03/03/2015] [Accepted: 03/03/2015] [Indexed: 11/09/2022]
Abstract
Paramyotonia congenita (PC) is a rare autosomal dominant neuromuscular disorder characterized by juvenile onset and development of cold-induced myotonia after repeated activities. The disease is mostly caused by genetic mutations of the sodium channel, voltage-gated, type IV, alpha subunit (SCN4A) gene. This study intended to systematically identify the causative genetic variations of a Chinese Han PC family. Seven members of this PC family, including four patients and three healthy controls, were selected for whole exome sequencing (WES) using the Illumina HiSeq platform. Sequence variations were identified using the SoftGenetics program. The mutation R1448C of SCN4A was found to be the only causative mutation. This study applied WES technology to sequence multiple members of a large PC family and was the first to systematically confirm that the genetic change in SCN4A is the only causative variation in this PC family and the SCN4A mutation is sufficient to lead to PC.
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Affiliation(s)
- Jinxin Li
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Qinghai Huang
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Liang Ge
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Jing Xu
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Xingjuan Shi
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Wei Xie
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Xiang Liu
- Hainan Medical University, Hainan 571199, China
| | - Xiangdong Liu
- Key Laboratory of Developmental Genes and Human Diseases, Institute of Life Sciences, Southeast University, Nanjing 210096, China
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Shiah IS, Lin CL, Yang SN. Concurrent hypokalemic periodic paralysis and bipolar disorder. JOURNAL OF MEDICAL SCIENCES 2015. [DOI: 10.4103/1011-4564.167779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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26
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Zimmer T, Haufe V, Blechschmidt S. Voltage-gated sodium channels in the mammalian heart. Glob Cardiol Sci Pract 2014; 2014:449-63. [PMID: 25780798 PMCID: PMC4355518 DOI: 10.5339/gcsp.2014.58] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/11/2014] [Indexed: 12/19/2022] Open
Abstract
Mammalian species express nine functional voltage-gated Na(+) channels. Three of them, the cardiac-specific isoform Nav1.5 and the neuronal isoforms Nav1.8 and Nav1.9, are relatively resistant to the neurotoxin tetrodotoxin (TTX; IC50 ≥ 1 μM). The other six isoforms are highly sensitive to TTX with IC50 values in the nanomolar range. These isoforms are expressed in the central nervous system (Nav1.1, Nav1.2, Nav1.3, Nav1.6), in the skeletal muscle (Nav1.4), and in the peripheral nervous system (Nav1.6, Nav1.7). The isoform Nav1.5, encoded by the SCN5A gene, is responsible for the upstroke of the action potential in the heart. Mutations in SCN5A are associated with a variety of life-threatening arrhythmias, like long QT syndrome type 3 (LQT3), Brugada syndrome (BrS) or cardiac conduction disease (CCD). Previous immunohistochemical and electrophysiological assays demonstrated the cardiac expression of neuronal and skeletal muscle Na(+) channels in the heart of various mammals, which led to far-reaching speculations on their function. However, when comparing the Na(+) channel mRNA patterns in the heart of various mammalian species, only minute quantities of transcripts for TTX-sensitive Na(+) channels were detectable in whole pig and human hearts, suggesting that these channels are not involved in cardiac excitation phenomena in higher mammals. This conclusion is strongly supported by the fact that mutations in TTX-sensitive Na(+) channels were associated with epilepsy or skeletal muscle diseases, rather than with a pathological cardiac phenotype. Moreover, previous data from TTX-intoxicated animals and from cases of human tetrodotoxication showed that low TTX dosages caused at most little alterations of both the cardiac output and the electrocardiogram. Recently, genome-wide association studies identified SCN10A, the gene encoding Nav1.8, as a determinant of cardiac conduction parameters, and mutations in SCN10A have been associated with BrS. These novel findings opened a fascinating new research area in the cardiac ion channel field, and the on-going debate on how SCN10A/Nav1.8 affects cardiac conduction is very exciting.
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Affiliation(s)
- Thomas Zimmer
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Kollegiengasse 9, 07743 Jena, Germany
| | | | - Steve Blechschmidt
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Kollegiengasse 9, 07743 Jena, Germany
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Bashir A, Saleem S, Wani M, Rasool R, Wani IY, Gulnar A, Verma S. Association of single nucleotide polymorphisms of CACNA1A gene in migraine. INDIAN JOURNAL OF HUMAN GENETICS 2014; 20:59-63. [PMID: 24959015 PMCID: PMC4065480 DOI: 10.4103/0971-6866.132757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION: Migraine is a chronic, neurovascular polygenic disease where genetic and environmental factors are involved in its etiology. Dysfunction of neuronal ion transportation can provide a model for predisposition for common forms of migraine. Mutations in genes encoding ion channels disturb the rhythmic function of exposed tissue that may also explain the episodic nature of migraine. Our aim was to study the single nucleotide polymorphisms of CACNA1A gene in migraine patients. MATERIALS AND METHODS: The subjects were the patients of migraine, in the age range of 18-80 years, diagnosed by a Neurologist, as per the diagnostic criteria of International Headache Society (IHS) Classification 2004 after excluding other causes of headache by clinical examination and relevant investigations. The controls were the age and sex matched healthy persons from the same population excluding the relatives of patients. Only those patients and the controls, who voluntarily participated in the study, were taken and their blood samples were taken for the study. Deoxyribonucleic acid (DNA) extraction was performed according to the manufacturer's protocol for Qiagen DNA extraction kits (Qiagen, Hilden, NRW, Germany). DNA content was quantified by spectrophotometric absorption (Nanodrop Spectrophotometer, BioLab, Scoresby, VIC, Australia). Polymerase chain reaction was performed using an iCycler Thermal Cycler (Bio.Rad, Hercules, CA, USA). The polymorphic analysis of CACNA1A gene was carried out by two methods: Restriction fragment length polymorphism and sequencing. RESULTS: The study included a total of 25 patients of migraine, diagnosed on out-patient department basis as per IHS Classification 2004 and compared with age and sex matched 25 healthy controls. Most of the patients 23 (92%) were below the age of 50 years. 20 of the patients (80%) were females and 5 (20%) were males. The polymorphic analysis of CACNA1A gene revealed the presence of only the wild form of the gene for the codon E993V in both case and control groups. CONCLUSION: In our study, we could not find any polymorphism of CACNA1A gene in the selected patients. Instead the wild type of genotype was found in both patients and controls. This negative result presented here, implies that if the CACNA1A gene is involved in typical migraine (with and without aura), its contribution is very modest and therefore difficult to discern. Nevertheless, there are other genes that could be considered potential candidates for typical migraine susceptibility for which further research is needed.
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Affiliation(s)
- Aadil Bashir
- Department of Neurology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Shiekh Saleem
- Department of Neurology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Maqbool Wani
- Department of Neurology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Roohi Rasool
- Department of Immunology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Irfan Yousuf Wani
- Department of Neurology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Azhara Gulnar
- Department of Neurology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
| | - Sawan Verma
- Department of Neurology, SKIMS, Soura, Srinagar, Jammu and Kashmir, India
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Marques I, Colaço AR, Costa PJ, Busschaert N, Gale PA, Félix V. Tris-thiourea tripodal-based molecules as chloride transmembrane transporters: insights from molecular dynamics simulations. SOFT MATTER 2014; 10:3608-3621. [PMID: 24663079 DOI: 10.1039/c3sm52140k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interaction of six tripodal synthetic chloride transmembrane transporters with a POPC bilayer was investigated by means of molecular dynamics simulations using the general Amber force field (GAFF) for the transporters and the LIPID11 force field for phospholipids. These transporters are structurally simple molecules, based on the tris(2-aminoethyl)amine scaffold, containing three thiourea binding units coupled with three n-butyl (1), phenyl (2), fluorophenyl (3), pentafluorophenyl (4), trifluoromethylphenyl (5), or bis(trifluoromethyl)phenyl (6) substituents. The passive diffusion of 1-6⊃ Cl(-) was evaluated with the complexes initially positioned either in the water phase or inside the bilayer. In the first scenario the chloride is released in the water solution before the synthetic molecules achieve the water-lipid interface and permeate the membrane. In the latter one, only when the chloride complex reaches the interface is the anion released to the water phase, with the transporter losing the initial ggg tripodal shape. Independently of the transporter used in the membrane system, the bilayer structure is preserved and the synthetic molecules interact with the POPC molecules at the phosphate headgroup level, via N-H···O hydrogen bonds. Overall, the molecular dynamics simulations' results indicate that the small tripodal molecules in this series have a low impact on the bilayer and are able to diffuse with chloride inside the lipid environment. Indeed, these are essential conditions for these molecules to promote the transmembrane transport as anion carriers, in agreement with experimental efflux data.
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Affiliation(s)
- Igor Marques
- Departamento de Química, CICECO and Secção Autónoma de Ciências da Saúde, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
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Robertson JWF, Kasianowicz JJ, Banerjee S. Analytical Approaches for Studying Transporters, Channels and Porins. Chem Rev 2012; 112:6227-49. [DOI: 10.1021/cr300317z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Joseph W. F. Robertson
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - John J. Kasianowicz
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - Soojay Banerjee
- National
Institute of Neurological
Disorders and Stroke, Bethesda, Maryland 20824, United States
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30
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Terpitz U, Sukhorukov VL, Zimmermann D. Prototype for automatable, dielectrophoretically-accessed intracellular membrane-potential measurements by metal electrodes. Assay Drug Dev Technol 2012; 11:9-16. [PMID: 22994967 DOI: 10.1089/adt.2012.455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Functional access to membrane proteins, for example, ion channels, of individual cells is an important prerequisite in drug discovery studies. The highly sophisticated patch-clamp method is widely used for electrogenic membrane proteins, but is demanding for the operator, and its automation remains challenging. The dielectrophoretically-accessed, intracellular membrane-potential measurement (DAIMM) method is a new technique showing high potential for automation of electrophysiological data recording in the whole-cell configuration. A cell suspension is brought between a mm-scaled planar electrode and a μm-scaled tip electrode, placed opposite to each other. Due to the asymmetric electrode configuration, the application of alternating electric fields (1-5 MHz) provokes a dielectrophoretic force acting on the target cell. As a consequence, the cell is accelerated and pierced by the tip electrode, hence functioning as the internal (working) electrode. We used the light-gated cation channel Channelrhodopsin-2 as a reporter protein expressed in HEK293 cells to characterize the DAIMM method in comparison with the patch-clamp technique.
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Affiliation(s)
- Ulrich Terpitz
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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31
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Gentile S. Ion channel phosphorylopathy: a link between genomic variation and human disease. ChemMedChem 2012; 7:1757-61. [PMID: 22927196 DOI: 10.1002/cmdc.201200236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 08/07/2012] [Indexed: 11/06/2022]
Abstract
Voltage-gated ion channels (VGIC) regulate many important physiological events, including muscle contraction, brain function, and secretion. Mutations that inhibit or up-regulate VGIC activities can dramatically interfere with the normal function of several organs, leading to unpredictable failure and therefore poor quality of life or even death. Many genomic variations that change amino acids in cytoplasmic domains of ion channels have been found to be associated with several diseases, including cardiac arrhythmias and neurodegeneration. However, a mechanism linking these mutations to ion channel malfunction has not been clearly established and in some cases is totally unknown. This concept article gives an overview on a possible mechanism by which disease-associated mutations in cytoplasmic domains of ion channels can affect channel activity by creating or disrupting phosphorylation sites for specific kinases. We call these events "ion channel phosphorylopathies". Understanding ion channel phosphorylopathies offers the opportunity to find a mechanism linking genomic variations to human disease and is crucial to the process of designing an effective pharmacological strategy.
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Affiliation(s)
- Saverio Gentile
- Department of Molecular Pharmacology and Therapeutics, Loyola University Medical Center, 2160 South First Ave., Bldg. 102, Rm. 3621, Maywood, IL 60153, USA.
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32
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Goldberg YP, Pimstone SN, Namdari R, Price N, Cohen C, Sherrington RP, Hayden MR. Human Mendelian pain disorders: a key to discovery and validation of novel analgesics. Clin Genet 2012; 82:367-73. [PMID: 22845492 DOI: 10.1111/j.1399-0004.2012.01942.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/03/2012] [Accepted: 07/23/2012] [Indexed: 12/21/2022]
Abstract
We have utilized a novel application of human genetics, illuminating the important role that rare genetic disorders can play in the development of novel drugs that may be of relevance for the treatment of both rare and common diseases. By studying a very rare Mendelian disorder of absent pain perception, congenital indifference to pain, we have defined Nav1.7 (endocded by SCN9A) as a critical and novel target for analgesic development. Strong human validation has emerged with SCN9A gain-of-function mutations causing inherited erythromelalgia (IEM) and paroxysmal extreme pain disorder, both Mendelian disorder of spontaneous or easily evoked pain. Furthermore, variations in the Nav1.7 channel also modulate pain perception in healthy subjects as well as in painful conditions such as osteoarthritis and Parkinson disease. On the basis of this, we have developed a novel compound (XEN402) that exhibits potent, voltage-dependent block of Nav1.7. In a small pilot study, we showed that XEN402 blocks Nav1.7 mediated pain associated with IEM thereby demonstrating the use of rare genetic disorders with mutant target channels as a novel approach to rapid proof-of-concept. Our approach underscores the critical role that human genetics can play by illuminating novel and critical pathways pertinent for drug discovery.
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Affiliation(s)
- Y P Goldberg
- Department of Clinical Development, Xenon Pharmaceuticals Inc, Burnaby, British Columbia, Canada.
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Hermann A, Donato R, Weiger TM, Chazin WJ. S100 calcium binding proteins and ion channels. Front Pharmacol 2012; 3:67. [PMID: 22539925 PMCID: PMC3336106 DOI: 10.3389/fphar.2012.00067] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/03/2012] [Indexed: 12/23/2022] Open
Abstract
S100 Ca(2+)-binding proteins have been associated with a multitude of intracellular Ca(2+)-dependent functions including regulation of the cell cycle, cell differentiation, cell motility and apoptosis, modulation of membrane-cytoskeletal interactions, transduction of intracellular Ca(2+) signals, and in mediating learning and memory. S100 proteins are fine tuned to read the intracellular free Ca(2+) concentration and affect protein phosphorylation, which makes them candidates to modulate certain ion channels and neuronal electrical behavior. Certain S100s are secreted from cells and are found in extracellular fluids where they exert unique extracellular functions. In addition to their neurotrophic activity, some S100 proteins modulate neuronal electrical discharge activity and appear to act directly on ion channels. The first reports regarding these effects suggested S100-mediated alterations in Ca(2+) fluxes, K(+) currents, and neuronal discharge activity. Recent reports revealed direct and indirect interactions with Ca(2+), K(+), Cl(-), and ligand activated channels. This review focuses on studies of the physical and functional interactions of S100 proteins and ion channels.
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Affiliation(s)
- Anton Hermann
- Division of Cellular and Molecular Neurobiology, Department of Cell Biology, University of SalzburgSalzburg, Austria
| | - Rosario Donato
- Department of Experimental Medicine and Biochemical Sciences, University of PerugiaPerugia, Italy
| | - Thomas M. Weiger
- Division of Cellular and Molecular Neurobiology, Department of Cell Biology, University of SalzburgSalzburg, Austria
| | - Walter J. Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt UniversityNashville, TN, USA
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Sausbier U, Dullin C, Missbach-Guentner J, Kabagema C, Flockerzie K, Kuscher GM, Stuehmer W, Neuhuber W, Ruth P, Alves F, Sausbier M. Osteopenia due to enhanced cathepsin K release by BK channel ablation in osteoclasts. PLoS One 2011; 6:e21168. [PMID: 21695131 PMCID: PMC3114853 DOI: 10.1371/journal.pone.0021168] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 05/23/2011] [Indexed: 01/05/2023] Open
Abstract
Background The process of bone resorption by osteoclasts is regulated by Cathepsin K, the lysosomal collagenase responsible for the degradation of the organic bone matrix during bone remodeling. Recently, Cathepsin K was regarded as a potential target for therapeutic intervention of osteoporosis. However, mechanisms leading to osteopenia, which is much more common in young female population and often appears to be the clinical pre-stage of idiopathic osteoporosis, still remain to be elucidated, and molecular targets need to be identified. Methodology/Principal Findings We found, that in juvenile bone the large conductance, voltage and Ca2+-activated (BK) K+ channel, which links membrane depolarization and local increases in cytosolic calcium to hyperpolarizing K+ outward currents, is exclusively expressed in osteoclasts. In juvenile BK-deficient (BK−/−) female mice, plasma Cathepsin K levels were elevated two-fold when compared to wild-type littermates. This increase was linked to an osteopenic phenotype with reduced bone mineral density in long bones and enhanced porosity of trabecular meshwork in BK−/− vertebrae as demonstrated by high-resolution flat-panel volume computed tomography and micro-CT. However, plasma levels of sRANKL, osteoprotegerin, estrogene, Ca2+ and triiodthyronine as well as osteoclastogenesis were not altered in BK−/− females. Conclusion/Significance Our findings suggest that the BK channel controls resorptive osteoclast activity by regulating Cathepsin K release. Targeted deletion of BK channel in mice resulted in an osteoclast-autonomous osteopenia, becoming apparent in juvenile females. Thus, the BK−/− mouse-line represents a new model for juvenile osteopenia, and revealed the BK channel as putative new target for therapeutic controlling of osteoclast activity.
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Affiliation(s)
- Ulrike Sausbier
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Christian Dullin
- Department of Diagnostic Radiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Clement Kabagema
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Katarina Flockerzie
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Gerd Marten Kuscher
- Max-Planck-Institute for Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
| | - Walter Stuehmer
- Max-Planck-Institute for Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
| | - Winfried Neuhuber
- Institute for Anatomy, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Peter Ruth
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Frauke Alves
- Max-Planck-Institute for Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
- Department of Hematology and Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Matthias Sausbier
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
- * E-mail:
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35
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Sun C, Van Ghelue M, Tranebjaerg L, Thyssen F, Nilssen Ø, Torbergsen T. Myotonia congenita and myotonic dystrophy in the same family: coexistence of a CLCN1 mutation and expansion in the CNBP (ZNF9) gene. Clin Genet 2011; 80:574-80. [DOI: 10.1111/j.1399-0004.2010.01616.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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36
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Selected summaries from the XVII World Congress of Psychiatric Genetics, San Diego, California, USA, 4-8 November 2009. Psychiatr Genet 2010; 20:229-68. [PMID: 20706171 DOI: 10.1097/ypg.0b013e32833d17c3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The XVII World Congress of Psychiatric Genetics, sponsored by The International Society of Psychiatric Genetics (ISPG) took place in San Diego, California from 4 to 8 November 2009. Approximately 550 participants gathered to discuss the latest molecular genetic findings relevant to serious mental illness, including schizophrenia, mood disorders, substance abuse, autism, and attention deficit disorder. Recent advances in the field were discussed, including the genome-wide association studies results, copy number variation (CNV) in the genome, genomic imaging, and large multicenter collaborations. The following report, written by junior travel awardees who were assigned sessions as rapporteurs represents some of the areas covered in oral presentation during the conference, and reports on some of the notable major new findings described at this 2009 World Congress of Psychiatric Genetics.
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Burgunder JM, Finsterer J, Szolnoki Z, Fontaine B, Baets J, Van Broeckhoven C, Di Donato S, De Jonghe P, Lynch T, Mariotti C, Schöls L, Spinazzola A, Tabrizi SJ, Tallaksen C, Zeviani M, Harbo HF, Gasser T. EFNS guidelines on the molecular diagnosis of channelopathies, epilepsies, migraine, stroke, and dementias. Eur J Neurol 2010; 17:641-8. [DOI: 10.1111/j.1468-1331.2010.02985.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Toward rational design of electrical stimulation strategies for epilepsy control. Epilepsy Behav 2010; 17:6-22. [PMID: 19926525 PMCID: PMC2818293 DOI: 10.1016/j.yebeh.2009.10.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 10/12/2009] [Indexed: 11/21/2022]
Abstract
Electrical stimulation is emerging as a viable alternative for patients with epilepsy whose seizures are not alleviated by drugs or surgery. Its attractions are temporal and spatial specificity of action, flexibility of waveform parameters and timing, and the perception that its effects are reversible unlike resective surgery. However, despite significant advances in our understanding of mechanisms of neural electrical stimulation, clinical electrotherapy for seizures relies heavily on empirical tuning of parameters and protocols. We highlight concurrent treatment goals with potentially conflicting design constraints that must be resolved when formulating rational strategies for epilepsy electrotherapy, namely, seizure reduction versus cognitive impairment, stimulation efficacy versus tissue safety, and mechanistic insight versus clinical pragmatism. First, treatment markers, objectives, and metrics relevant to electrical stimulation for epilepsy are discussed from a clinical perspective. Then the experimental perspective is presented, with the biophysical mechanisms and modalities of open-loop electrical stimulation, and the potential benefits of closed-loop control for epilepsy.
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Alaynick WA, Way JM, Wilson SA, Benson WG, Pei L, Downes M, Yu R, Jonker JW, Holt JA, Rajpal DK, Li H, Stuart J, McPherson R, Remlinger KS, Chang CY, McDonnell DP, Evans RM, Billin AN. ERRgamma regulates cardiac, gastric, and renal potassium homeostasis. Mol Endocrinol 2009; 24:299-309. [PMID: 19965931 DOI: 10.1210/me.2009-0114] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Energy production by oxidative metabolism in kidney, stomach, and heart, is primarily expended in establishing ion gradients to drive renal electrolyte homeostasis, gastric acid secretion, and cardiac muscle contraction, respectively. In addition to orchestrating transcriptional control of oxidative metabolism, the orphan nuclear receptor, estrogen-related receptor gamma (ERRgamma), coordinates expression of genes central to ion homeostasis in oxidative tissues. Renal, gastric, and cardiac tissues subjected to genomic analysis of expression in perinatal ERRgamma null mice revealed a characteristic dysregulation of genes involved in transport processes, exemplified by the voltage-gated potassium channel, Kcne2. Consistently, ERRgamma null animals die during the first 72 h of life with elevated serum potassium, reductions in key gastric acid production markers, and cardiac arrhythmia with prolonged QT intervals. In addition, we find altered expression of several genes associated with hypertension in ERRgamma null mice. These findings suggest a potential role for genetic polymorphisms at the ERRgamma locus and ERRgamma modulators in the etiology and treatment of renal, gastric, and cardiac dysfunction.
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Affiliation(s)
- William A Alaynick
- Gene Expression Laboratory and the Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
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40
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Valenti MP, Cretin B, Rudolf G, Dylgjeri S, De Saint-Martin A, Hirsch E. [Is there a bridge between migraine and familial mesial temporal lobe epilepsy?]. Rev Neurol (Paris) 2009; 165:774-81. [PMID: 19762056 DOI: 10.1016/j.neurol.2009.07.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 07/28/2009] [Indexed: 11/29/2022]
Abstract
Numerous reviews have emphasized the links between certain types of epilepsy and migraine. Historically, Gowers was one of the first, in 1907, to have drawn attention to a possible relationship between migraine headache and epilepsy in a period when no additional examination was available. In the last two decades, progress in molecular biology, electrophysiology, and neuro-imaging has enabled a better approach to the fundamental elements underlying the interrelationship between these two nosological domains. During this same time, a new term "channelopathy" has appeared in the literature. This term groups together affections involving a dysfunction of ion channels. In this article, the links between the different types of migraine and familial mesial temporal lobe epilepsy are illustrated by two case reports. This association does not appear to occur at random but would undoubtedly depend on a common genetic substratum, leading to a direct comorbidity. These occasional recurring symptoms would lie within the framework of a more general concept of "Primary Brain Channelopathies".
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Affiliation(s)
- M P Valenti
- Pôle tête-cou-CETD, LINC-UMR, CNRS, Strasbourg, France
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41
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Pons R. The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism. J Inherit Metab Dis 2009; 32:321-32. [PMID: 19107571 DOI: 10.1007/s10545-008-1007-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2008] [Revised: 10/15/2008] [Accepted: 10/17/2008] [Indexed: 11/28/2022]
Abstract
Paediatric neurotransmitter diseases are a group of inherited disorders attributable to a disturbance of neurotransmitter metabolism. The monoamines, catecholamines and serotonin, also called biogenic amines, are neurotransmitters with multiple roles including psychomotor function, hormone secretion, cardiovascular, respiratory and gastrointestinal control, sleep mechanisms, body temperature and pain. Given the multiple functions of monoamines, disorders of their metabolism comprise a wide spectrum of manifestations, with motor dysfunction being the most prominent clinical feature. The severity of the clinical manifestations ranges from mild to severe. Patients with severe and intermediate phenotypes may present with infantile parkinsonism that differs in a number of aspects from the parkinsonism in nigrostriatal degeneration. Analysis of monoamine metabolites and pterins in spinal fluid assists in the diagnosis of these disorders. Treatment options include tetrahydrobiopterin supplementation, L: -dopa, 5-hydroxytryptophan, and medications that potentiate monoamine transmission. Response to treatment is variable.
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Affiliation(s)
- R Pons
- First Department of Paediatrics, Agia Sofia Hospital, Thivon & Papadiamantopoulou, Athens 115 27, Greece.
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42
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Khodorova A, Montmayeur JP, Strichartz G. Endothelin receptors and pain. THE JOURNAL OF PAIN 2009; 10:4-28. [PMID: 19111868 DOI: 10.1016/j.jpain.2008.09.009] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 09/08/2008] [Accepted: 09/30/2008] [Indexed: 12/11/2022]
Abstract
UNLABELLED The endogenous endothelin (ET) peptides participate in a remarkable variety of pain-relatedprocesses. Pain that is elevated by inflammation, by skin incision, by cancer, during a Sickle Cell Disease crisis and by treatments that mimic neuropathic and inflammatory pain and are all reduced by local administration of antagonists of endothelin receptors. Many effects of endogenously released endothelin are simulated by acute, local subcutaneous administration of endothelin, which at very high concentrations causes pain and at lower concentrations sensitizes the nocifensive reactions to mechanical, thermal and chemical stimuli. PERSPECTIVE In this paper we review the biochemistry, second messenger pathways and hetero-receptor coupling that are activated by ET receptors, the cellular physiological responses to ET receptor activation, and the contribution to pain of such mechanisms occurring in the periphery and the CNS. Our goal is to frame the subject of endothelin and pain for a broad readership, and to present the generally accepted as well as the disputed concepts, including important unanswered questions.
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Affiliation(s)
- Alla Khodorova
- Department of Anesthesiology, Perioperative and Pain Medicine, Pain Research Center, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115-6110, USA
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Recent advances in electrophysiology-based screening technology and the impact upon ion channel discovery research. Methods Mol Biol 2009; 565:187-208. [PMID: 19551363 DOI: 10.1007/978-1-60327-258-2_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ion channels are recognised as an increasingly tractable class of targets for the discovery and development of new drugs, with a diverse range of ion channel proteins now implicated across a wide variety of disease states and potential therapeutic applications. Whilst the field now ranks as one of the most dynamic fields for drug discovery research, it has historically been regarded by many researchers as a class of proteins associated with numerous technical challenges. Recent advances in our understanding of molecular biology and the increasing acceptance of electrophysiology-based screening methodology mean that ion channels are rapidly progressing towards universal acceptance as worthy and approachable targets for drug discovery. This chapter will outline the commercially available electrophysiology-based screening technologies and give an overview of the range of options for progressing pharmaceutical research and development against this important target class.
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Guerin AA, Feigenbaum A, Donner EJ, Yoon G. Stepwise developmental regression associated with novel CACNA1A mutation. Pediatr Neurol 2008; 39:363-4. [PMID: 18940563 DOI: 10.1016/j.pediatrneurol.2008.07.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/23/2008] [Accepted: 07/28/2008] [Indexed: 11/28/2022]
Abstract
Mutations in CACNA1A were previously described in familial hemiplegic migraine, episodic ataxia type 2, and spinocerebellar ataxia type 6. We report on an 11-year-old girl with episodes of seizures, ataxia, headache, a decreased level of consciousness, and motor regression, with a background of mental retardation and mild cerebellar atrophy. Sequence analysis of the CACNA1A gene revealed a de novo Ile712Val sequence variant, which was not reported previously.
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Affiliation(s)
- Andrea A Guerin
- Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Canada
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Garrido-Sanabria ER, Otalora LFP, Arshadmansab MF, Herrera B, Francisco S, Ermolinsky BS. Impaired expression and function of group II metabotropic glutamate receptors in pilocarpine-treated chronically epileptic rats. Brain Res 2008; 1240:165-76. [PMID: 18804094 DOI: 10.1016/j.brainres.2008.08.084] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 08/19/2008] [Accepted: 08/21/2008] [Indexed: 01/16/2023]
Abstract
Group II metabotropic (mGlu II) receptor subtypes mGlu2 and mGlu3 are important modulators of synaptic plasticity and glutamate release in the brain. Accordingly, several pharmacological ligands have been designed to target these receptors for the treatment of neurological disorders characterized by anomalous glutamate regulation including epilepsy. In this study, we examine whether the expression level and function of mGlu2 and mGlu3 are altered in experimental epilepsy by using immunohistochemistry, Western blot analysis, RT-PCR and extracellular recordings. A down-regulation of mGlu2/3 protein expression at the mossy fiber pathway was associated with a significant reduction in mGlu2/3 protein expression in the hippocampus and cortex of chronically epileptic rats. Moreover, a reduction in mGlu2 and mGlu3 transcripts levels was noticed as early as 24 h after pilocarpine-induced status epilepticus (SE) and persisted during subsequent "latent" and chronic periods. In addition, a significant impairment of mGlu II-mediated depression of field excitatory postsynaptic potentials at mossy fiber-CA3 synapses was detected in chronically epileptic rats. Application of mGlu II agonists (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV) induced a significant reduction of the fEPSP amplitude in control rats, but not in chronic epileptic rats. These data indicate a long-lasting impairment of mGlu2/3 expression that may contribute to abnormal presynaptic plasticity, exaggerate glutamate release and hyperexcitability in temporal lobe epilepsy.
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Affiliation(s)
- Emilio R Garrido-Sanabria
- Department of Biological Sciences, The University of Texas at Brownsville, Texas Southmost College, USA.
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Ebert AM, McAnelly CA, Handschy AV, Mueller RL, Horne WA, Garrity DM. Genomic organization, expression, and phylogenetic analysis of Ca2+ channel beta4 genes in 13 vertebrate species. Physiol Genomics 2008; 35:133-44. [PMID: 18682574 DOI: 10.1152/physiolgenomics.90264.2008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Ca(2+) channel beta-subunits, encoded by CACNB genes 1-4, are membrane-associated guanylate kinase (MAGUK) proteins. As auxiliary subunits of voltage-gated Ca(2+) channels, the beta-subunits facilitate membrane trafficking of the pore-forming alpha1 subunits and regulate voltage-dependent channel gating. In this report, we investigate whether two zebrafish beta4 genes, beta4.1 and beta4.2, have diverged in structure and function over time. Comparative expression analyses indicated that beta4.1 and beta4.2 were expressed in separable domains within the developing brain and other tissues. Alternative splicing in both genes was subject to differential temporal and spatial regulation, with some organs expressing different subsets of beta4.1 and beta4.2 transcript variants. We used several genomic tools to identify and compare predicted cDNAs for eight teleost and five tetrapod beta4 genes. Teleost species had either one or two beta4 paralogs, whereas each tetrapod species contained only one. Teleost beta4.1 and beta4.2 genes had regions of sequence divergence, but compared with tetrapod beta4s, they exhibited similar exon/intron structure, strong conservation of residues involved in alpha1 subunit binding, and similar 5' alternative splicing. Phylogenetic results are consistent with the duplicate teleost beta4 genes resulting from the teleost whole genome duplication. Following duplication, the beta4.1 genes have evolved faster than beta4.2 genes. We identified disproportionately large second and third introns in several beta4 genes, which we propose may provide regulatory elements contributing to their differential tissue expression. In sum, both mRNA expression data and phylogenetic analysis support the evolutionary divergence of beta4.1 and beta4.2 subunit function.
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Affiliation(s)
- Alicia M Ebert
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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Urbano FJ, Pagani MR, Uchitel OD. Calcium channels, neuromuscular synaptic transmission and neurological diseases. J Neuroimmunol 2008; 201-202:136-44. [PMID: 18678414 DOI: 10.1016/j.jneuroim.2008.06.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 01/20/2023]
Abstract
Voltage-dependent calcium channels are essential in neuronal signaling and synaptic transmission, and their functional alterations underlie numerous human disorders whether monogenic (e.g., ataxia, migraine, etc.) or autoimmune. We review recent work on Ca(V)2.1 or P/Q channelopathies, mostly using neuromuscular junction preparations, and focus specially on the functional hierarchy among the calcium channels recruited to mediate neurotransmitter release when Ca(V)2.1 channels are mutated or depleted. In either case, synaptic transmission is greatly compromised; evidently, none of the reported functional replacements with other calcium channels compensates fully.
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Affiliation(s)
- Francisco J Urbano
- Laboratorio de Fisiología y Biología Molecular, Instituto de Fisiología y Biología Molecular y Neurociencias, Universidad de Buenos Aires-CONICET, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, C1428-Buenos Aires, Argentina
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