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Abreo TJ, Thompson EC, Madabushi A, Soh H, Varghese N, Vanoye CG, Springer K, Park KL, Johnson J, Sims S, Ji Z, Chavez AG, Jankovic MJ, Habte B, Zuberi AR, Lutz C, Wang Z, Krishnan V, Dudler L, Einsele-Scholz S, Noebels JL, George AL, Maheshwari A, Tzingounis AV, Cooper EC. Plural molecular and cellular mechanisms of pore domain KCNQ2 encephalopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.04.574177. [PMID: 38260608 PMCID: PMC10802467 DOI: 10.1101/2024.01.04.574177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
KCNQ2 variants in children with neurodevelopmental impairment are difficult to assess due to their heterogeneity and unclear pathogenic mechanisms. We describe a child with neonatal-onset epilepsy, developmental impairment of intermediate severity, and KCNQ2 G256W heterozygosity. Analyzing prior KCNQ2 channel cryoelectron microscopy models revealed G256 as a node of an arch-shaped non-covalent bond network linking S5, the pore turret, and the ion path. Co-expression with G256W dominantly suppressed conduction by wild-type subunits in heterologous cells. Ezogabine partly reversed this suppression. G256W/+ mice have epilepsy leading to premature deaths. Hippocampal CA1 pyramidal cells from G256W/+ brain slices showed hyperexcitability. G256W/+ pyramidal cell KCNQ2 and KCNQ3 immunolabeling was significantly shifted from axon initial segments to neuronal somata. Despite normal mRNA levels, G256W/+ mouse KCNQ2 protein levels were reduced by about 50%. Our findings indicate that G256W pathogenicity results from multiplicative effects, including reductions in intrinsic conduction, subcellular targeting, and protein stability. These studies provide evidence for an unexpected and novel role for the KCNQ2 pore turret and introduce a valid animal model of KCNQ2 encephalopathy. Our results, spanning structure to behavior, may be broadly applicable because the majority of KCNQ2 encephalopathy patients share variants near the selectivity filter.
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Affiliation(s)
- Timothy J. Abreo
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Emma C. Thompson
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Anuraag Madabushi
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Carlos G. Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Kristen L. Park
- Department of Pediatrics, Childrens Colorado, University of Colorado, Aurora, CO, USA
- Department of Neurology, Childrens Colorado, University of Colorado, Aurora, CO, USA
| | | | | | - Zhigang Ji
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Ana G. Chavez
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | | | - Bereket Habte
- Department of Pediatrics, Childrens Colorado, University of Colorado, Aurora, CO, USA
- Department of Neurology, Childrens Colorado, University of Colorado, Aurora, CO, USA
| | - Aamir R. Zuberi
- The Rare Disease Translational Center & Technology Evaluation and Development, The Jackson Laboratory, Bar Harbor, ME, USA
| | - Cathleen Lutz
- The Rare Disease Translational Center & Technology Evaluation and Development, The Jackson Laboratory, Bar Harbor, ME, USA
| | - Zhao Wang
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
- CryoEM Core, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Vaishnav Krishnan
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Lisa Dudler
- Center for Human Genetics Tübingen, Tübingen, Germany
| | | | - Jeffrey L. Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Alfred L. George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | | | - Edward C. Cooper
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
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Pozzi E, Terribile G, Cherchi L, Di Girolamo S, Sancini G, Alberti P. Ion Channel and Transporter Involvement in Chemotherapy-Induced Peripheral Neurotoxicity. Int J Mol Sci 2024; 25:6552. [PMID: 38928257 PMCID: PMC11203899 DOI: 10.3390/ijms25126552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.
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Affiliation(s)
- Eleonora Pozzi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Giulia Terribile
- Human Physiology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.T.); (G.S.)
| | - Laura Cherchi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Sara Di Girolamo
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Giulio Sancini
- Human Physiology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.T.); (G.S.)
| | - Paola Alberti
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
- Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
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3
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Graziano B, Wang L, White OR, Kaplan DH, Fernandez-Abascal J, Bianchi L. Glial KCNQ K + channels control neuronal output by regulating GABA release from glia in C. elegans. Neuron 2024; 112:1832-1847.e7. [PMID: 38460523 PMCID: PMC11156561 DOI: 10.1016/j.neuron.2024.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/22/2024] [Accepted: 02/16/2024] [Indexed: 03/11/2024]
Abstract
KCNQs are voltage-gated K+ channels that control neuronal excitability and are mutated in epilepsy and autism spectrum disorder (ASD). KCNQs have been extensively studied in neurons, but their function in glia is unknown. Using voltage, calcium, and GABA imaging, optogenetics, and behavioral assays, we show here for the first time in Caenorhabditis elegans (C. elegans) that glial KCNQ channels control neuronal excitability by mediating GABA release from glia via regulation of the function of L-type voltage-gated Ca2+ channels. Further, we show that human KCNQ channels have the same role when expressed in nematode glia, underscoring conservation of function across species. Finally, we show that pathogenic loss-of-function and gain-of-function human KCNQ2 mutations alter glia-to-neuron GABA signaling in distinct ways and that the KCNQ channel opener retigabine exerts rescuing effects. This work identifies glial KCNQ channels as key regulators of neuronal excitability via control of GABA release from glia.
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Affiliation(s)
- Bianca Graziano
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Lei Wang
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Olivia R White
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Daryn H Kaplan
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jesus Fernandez-Abascal
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Laura Bianchi
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Kandel MB, Zhuang GZ, Goins WF, Marzulli M, Zhang M, Glorioso JC, Kang Y, Levitt AE, Kwok WM, Levitt RC, Sarantopoulos KD. rdHSV-CA8 non-opioid analgesic gene therapy decreases somatosensory neuronal excitability by activating Kv7 voltage-gated potassium channels. Front Mol Neurosci 2024; 17:1398839. [PMID: 38783904 PMCID: PMC11112096 DOI: 10.3389/fnmol.2024.1398839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 04/18/2024] [Indexed: 05/25/2024] Open
Abstract
Chronic pain is common and inadequately treated, making the development of safe and effective analgesics a high priority. Our previous data indicate that carbonic anhydrase-8 (CA8) expression in dorsal root ganglia (DRG) mediates analgesia via inhibition of neuronal ER inositol trisphosphate receptor-1 (ITPR1) via subsequent decrease in ER calcium release and reduction of cytoplasmic free calcium, essential to the regulation of neuronal excitability. This study tested the hypothesis that novel JDNI8 replication-defective herpes simplex-1 viral vectors (rdHSV) carrying a CA8 transgene (vHCA8) reduce primary afferent neuronal excitability. Whole-cell current clamp recordings in small DRG neurons showed that vHCA8 transduction caused prolongation of their afterhyperpolarization (AHP), an essential regulator of neuronal excitability. This AHP prolongation was completely reversed by the specific Kv7 channel inhibitor XE-991. Voltage clamp recordings indicate an effect via Kv7 channels in vHCA8-infected small DRG neurons. These data demonstrate for the first time that vHCA8 produces Kv7 channel activation, which decreases neuronal excitability in nociceptors. This suppression of excitability may translate in vivo as non-opioid dependent behavioral- or clinical analgesia, if proven behaviorally and clinically.
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Affiliation(s)
- Munal B. Kandel
- Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Gerald Z. Zhuang
- Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, FL, United States
| | - William F. Goins
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Marco Marzulli
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Mingdi Zhang
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Joseph C. Glorioso
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Yuan Kang
- Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Alexandra E. Levitt
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology and Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Roy C. Levitt
- Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, FL, United States
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
- John T. MacDonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, United States
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Konstantinos D. Sarantopoulos
- Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, FL, United States
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
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5
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Khelfaoui H, Ibaceta-Gonzalez C, Angulo MC. Functional myelin in cognition and neurodevelopmental disorders. Cell Mol Life Sci 2024; 81:181. [PMID: 38615095 PMCID: PMC11016012 DOI: 10.1007/s00018-024-05222-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/18/2024] [Accepted: 03/30/2024] [Indexed: 04/15/2024]
Abstract
In vertebrates, oligodendrocytes (OLs) are glial cells of the central nervous system (CNS) responsible for the formation of the myelin sheath that surrounds the axons of neurons. The myelin sheath plays a crucial role in the transmission of neuronal information by promoting the rapid saltatory conduction of action potentials and providing neurons with structural and metabolic support. Saltatory conduction, first described in the peripheral nervous system (PNS), is now generally recognized as a universal evolutionary innovation to respond quickly to the environment: myelin helps us think and act fast. Nevertheless, the role of myelin in the central nervous system, especially in the brain, may not be primarily focused on accelerating conduction speed but rather on ensuring precision. Its principal function could be to coordinate various neuronal networks, promoting their synchronization through oscillations (or rhythms) relevant for specific information processing tasks. Interestingly, myelin has been directly involved in different types of cognitive processes relying on brain oscillations, and myelin plasticity is currently considered to be part of the fundamental mechanisms for memory formation and maintenance. However, despite ample evidence showing the involvement of myelin in cognition and neurodevelopmental disorders characterized by cognitive impairments, the link between myelin, brain oscillations, cognition and disease is not yet fully understood. In this review, we aim to highlight what is known and what remains to be explored to understand the role of myelin in high order brain processes.
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Affiliation(s)
- Hasni Khelfaoui
- Université Paris Cité, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, 75014, Paris, France
| | - Cristobal Ibaceta-Gonzalez
- Université Paris Cité, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, 75014, Paris, France
| | - Maria Cecilia Angulo
- Université Paris Cité, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, 75014, Paris, France.
- GHU-PARIS Psychiatrie Et Neurosciences, Hôpital Sainte Anne, 75014, Paris, France.
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6
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Müller S, Kartheus M, Hendinger E, Hübner DC, Schnell E, Rackow S, Bertsche A, Köhling R, Kirschstein T. Persistent Kv7.2/7.3 downregulation in the rat pilocarpine model of mesial temporal lobe epilepsy. Epilepsy Res 2024; 200:107296. [PMID: 38219422 DOI: 10.1016/j.eplepsyres.2024.107296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/04/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
Mutations within the Kv7.2 and Kv7.3 genes are well described causes for genetic childhood epilepsies. Knowledge on these channels in acquired focal epilepsy, especially in mesial temporal lobe epilepsy (mTLE), however, is scarce. Here, we used the rat pilocarpine model of drug-resistant mTLE to elucidate both expression and function by quantitative polymerase-chain reaction, immunohistochemistry, and electrophysiology, respectively. We found transcriptional downregulation of Kv7.2 and Kv7.3 as well as reduced Kv7.2 expression in epileptic CA1. Consequences were altered synaptic transmission, hyperexcitability which consisted of epileptiform afterpotentials, and increased susceptibility to acute GABAergic disinhibition. Importantly, blocking Kv7 channels with XE991 increased hyperexcitability in control tissue, but not in chronically epileptic tissue suggesting that the Kv7 deficit had precluded XE991 effects in this tissue. Conversely, XE991 resulted in comparable reduction of the paired-pulse ratio in both experimental groups implying preserved presynaptic Kv7.2 function of Schaffer collateral terminals. Consistent with Kv7.2/7.3 downregulation, the Kv7.3 channel opener β-hydroxybutyrate failed to mitigate hyperexcitability. Our findings demonstrate that compromised Kv7 function is not only relevant in genetic epilepsy, but also in acquired focal epilepsy. Moreover, they help explain reduced anti-seizure efficacy of Kv7 channel openers in drug-resistant epilepsy.
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Affiliation(s)
- Steffen Müller
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Mareike Kartheus
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Elisabeth Hendinger
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | | | - Emma Schnell
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Simone Rackow
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany
| | - Astrid Bertsche
- Department Neuropaediatrics, Hospital for Children and Adolescents, University Medicine Greifswald, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany; Center of Transdisciplinary Neurosciences Rostock (CTNR), University Medicine Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Germany; Center of Transdisciplinary Neurosciences Rostock (CTNR), University Medicine Rostock, Germany.
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Bayat A, Iavarone S, Miceli F, Jakobsen AV, Johannesen KM, Nikanorova M, Ploski R, Szymanska K, Flamini R, Cooper EC, Weckhuysen S, Taglialatela M, Møller RS. Phenotypic and functional assessment of two novel KCNQ2 gain-of-function variants Y141N and G239S and effects of amitriptyline treatment. Neurotherapeutics 2024; 21:e00296. [PMID: 38241158 PMCID: PMC10903081 DOI: 10.1016/j.neurot.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 01/21/2024] Open
Abstract
While loss-of-function (LoF) variants in KCNQ2 are associated with a spectrum of neonatal-onset epilepsies, gain-of-function (GoF) variants cause a more complex phenotype that precludes neonatal-onset epilepsy. In the present work, the clinical features of three patients carrying a de novo KCNQ2 Y141N (n = 1) or G239S variant (n = 2) respectively, are described. All three patients had a mild global developmental delay, with prominent language deficits, and strong activation of interictal epileptic activity during sleep. Epileptic seizures were not reported. The absence of neonatal seizures suggested a GoF effect and prompted functional testing of the variants. In vitro whole-cell patch-clamp electrophysiological experiments in Chinese Hamster Ovary cells transiently-transfected with the cDNAs encoding Kv7.2 subunits carrying the Y141N or G239S variants in homomeric or heteromeric configurations with Kv7.2 subunits, revealed that currents from channels incorporating mutant subunits displayed increased current densities and hyperpolarizing shifts of about 10 mV in activation gating; both these functional features are consistent with an in vitro GoF phenotype. The antidepressant drug amitriptyline induced a reversible and concentration-dependent inhibition of current carried by Kv7.2 Y141N and G239S mutant channels. Based on in vitro results, amitriptyline was prescribed in one patient (G239S), prompting a significant improvement in motor, verbal, social, sensory and adaptive behavior skillsduring the two-year-treatment period. Thus, our results suggest that KCNQ2 GoF variants Y141N and G239S cause a mild DD with prominent language deficits in the absence of neonatal seizures and that treatment with the Kv7 channel blocker amitriptyline might represent a potential targeted treatment for patients with KCNQ2 GoF variants.
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Affiliation(s)
- Allan Bayat
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department for Regional Health Research, University of Southern Denmark, Odense, Denmark; Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Stefano Iavarone
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Anne V Jakobsen
- Department of Pediatrics, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department of Genetics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Marina Nikanorova
- Department of Pediatrics, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark
| | - Rafal Ploski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | - Krystyna Szymanska
- Department of Pediatric Neurology, Medical University of Warsaw, Warsaw, Poland
| | | | - Edward C Cooper
- Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston TX, USA
| | - Sarah Weckhuysen
- Applied and Translational Genomics Group, VIB-Center for Molecular Neurology, VIB, University of Antwerp, Antwerp, Belgium; Neurology Department, University Hospital Antwerp, Antwerp, Belgium; Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium; μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department for Regional Health Research, University of Southern Denmark, Odense, Denmark
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8
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Sharples SA, Broadhead MJ, Gray JA, Miles GB. M-type potassium currents differentially affect activation of motoneuron subtypes and tune recruitment gain. J Physiol 2023; 601:5751-5775. [PMID: 37988235 DOI: 10.1113/jp285348] [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: 07/27/2023] [Accepted: 10/25/2023] [Indexed: 11/23/2023] Open
Abstract
The size principle is a key mechanism governing the orderly recruitment of motor units and is believed to be dependent on passive properties of the constituent motoneurons. However, motoneurons are endowed with voltage-sensitive ion channels that create non-linearities in their input-output functions. Here we describe a role for the M-type potassium current, conducted by KCNQ channels, in the control of motoneuron recruitment in mice. Motoneurons were studied with whole-cell patch clamp electrophysiology in transverse spinal slices and identified based on delayed (fast) and immediate (slow) onsets of repetitive firing. M-currents were larger in delayed compared to immediate firing motoneurons, which was not reflected by variations in the presence of Kv7.2 or Kv7.3 subunits. Instead, a more depolarized spike threshold in delayed-firing motoneurons afforded a greater proportion of the total M-current to become activated within the subthreshold voltage range, which translated to a greater influence on their recruitment with little influence on their firing rates. Pharmacological activation of M-currents also influenced motoneuron recruitment at the population level, producing a rightward shift in the recruitment curve of monosynaptic reflexes within isolated mouse spinal cords. These results demonstrate a prominent role for M-type potassium currents in regulating the function of motor units, which occurs primarily through the differential control of motoneuron subtype recruitment. More generally, these findings highlight the importance of active properties mediated by voltage-sensitive ion channels in the differential control of motoneuron recruitment, which is a key mechanism for the gradation of muscle force. KEY POINTS: M-currents exert an inhibitory influence on spinal motor output. This inhibitory influence is exerted by controlling the recruitment, but not the firing rate, of high-threshold fast-like motoneurons, with limited influence on low-threshold slow-like motoneurons. Preferential control of fast motoneurons may be linked to a larger M-current that is activated within the subthreshold voltage range compared to slow motoneurons. Larger M-currents in fast compared to slow motoneurons are not accounted for by differences in Kv7.2 or Kv7.3 channel composition. The orderly recruitment of motoneuron subtypes is shaped by differences in the contribution of voltage-gated ion channels, including KCNQ channels. KCNQ channels may provide a target to dynamically modulate the recruitment gain across the motor pool and readily adjust movement vigour.
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Affiliation(s)
- Simon A Sharples
- School of Psychology and Neuroscience, University of St Andrews, Fife, UK
| | | | - James A Gray
- School of Psychology and Neuroscience, University of St Andrews, Fife, UK
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, Fife, UK
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9
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Lugg A, Schindle M, Sivak A, Tankisi H, Jones KE. Nerve excitability measured with the TROND protocol in amyotrophic lateral sclerosis: a systematic review and meta-analysis. J Neurophysiol 2023; 130:1480-1491. [PMID: 37910562 DOI: 10.1152/jn.00174.2023] [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] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/03/2023] Open
Abstract
This meta-analysis assessed the 30+ nerve excitability indices generated by the TROND protocol to identify potential biomarkers for amyotrophic lateral sclerosis (ALS). A comprehensive search was conducted in multiple databases to identify human studies that tested median motor axons. Forest plot analyses were performed using a random-effects model to determine the pooled effect (Z-score), heterogeneity (I2), and Cohen's d for potential biomarker identification. Out of 2,866 studies, 23 studies met the inclusion criteria, incorporating data from 719 controls and 942 patients with ALS. Seven indices emerged as potential biomarkers: depolarizing threshold electrotonus (TEd) 90-100 ms, strength-duration time constant (SDTC), superexcitability, TEd 40-60 ms, resting I/V slope, 50% depolarizing I/V, and subexcitability (ranked by the magnitude of the difference between patients and controls from largest to smallest). In a sensitivity analysis focusing on patients with larger compound muscle action potentials (CMAPs), only four indices were potential biomarkers: TEd 10-20 ms, TEd 90-100 ms, superexcitability, and SDTC. Among the extensive range of 30+ excitability indices generated by the TROND protocol, we have identified seven indices that effectively differentiate patients with ALS from healthy controls. Furthermore, a smaller subset of four indices shows promise as potential biomarkers when the CMAP remains relatively large. However, most studies were considered to be at moderate risk of bias due to case-control designs and absence of sensitivity and specificity calculations, underscoring the need for more prospective diagnostic test-accuracy studies with appropriate disease controls.NEW & NOTEWORTHY This meta-analysis uncovers seven potential axonal excitability biomarkers for lower motor neuron pathology in ALS, shedding light on ion channel dysfunction. The identified dysfunction aligns with the primary pathology-protein homeostasis disruption. These biomarkers could fill a gap to detect presymptomatic spread of the disease in the spinal cord and monitor treatments targeting protein homeostasis and limiting spread, toward enhancing patient care.
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Affiliation(s)
- Anna Lugg
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Mason Schindle
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Allison Sivak
- University of Alberta Library, Edmonton, Alberta, Canada
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Kelvin E Jones
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Neuroscience and Mental Health Institute, Edmonton, Alberta, Canada
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10
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Shi X, Lu C, Corman A, Nikish A, Zhou Y, Platt RJ, Iossifov I, Zhang F, Pan JQ, Sanjana NE. Heterozygous deletion of the autism-associated gene CHD8 impairs synaptic function through widespread changes in gene expression and chromatin compaction. Am J Hum Genet 2023; 110:1750-1768. [PMID: 37802044 PMCID: PMC10577079 DOI: 10.1016/j.ajhg.2023.09.004] [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: 03/14/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 10/08/2023] Open
Abstract
Whole-exome sequencing of autism spectrum disorder (ASD) probands and unaffected family members has identified many genes harboring de novo variants suspected to play a causal role in the disorder. Of these, chromodomain helicase DNA-binding protein 8 (CHD8) is the most recurrently mutated. Despite the prevalence of CHD8 mutations, we have little insight into how CHD8 loss affects genome organization or the functional consequences of these molecular alterations in neurons. Here, we engineered two isogenic human embryonic stem cell lines with CHD8 loss-of-function mutations and characterized differences in differentiated human cortical neurons. We identified hundreds of genes with altered expression, including many involved in neural development and excitatory synaptic transmission. Field recordings and single-cell electrophysiology revealed a 3-fold decrease in firing rates and synaptic activity in CHD8+/- neurons, as well as a similar firing-rate deficit in primary cortical neurons from Chd8+/- mice. These alterations in neuron and synapse function can be reversed by CHD8 overexpression. Moreover, CHD8+/- neurons displayed a large increase in open chromatin across the genome, where the greatest change in compaction was near autism susceptibility candidate 2 (AUTS2), which encodes a transcriptional regulator implicated in ASD. Genes with changes in chromatin accessibility and expression in CHD8+/- neurons have significant overlap with genes mutated in probands for ASD, intellectual disability, and schizophrenia but not with genes mutated in healthy controls or other disease cohorts. Overall, this study characterizes key molecular alterations in genome structure and expression in CHD8+/- neurons and links these changes to impaired neuronal and synaptic function.
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Affiliation(s)
- Xi Shi
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Broad Institute, Cambridge, MA, USA; Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA, USA
| | - Congyi Lu
- New York Genome Center, New York, NY, USA; Department of Biology, New York University, New York, NY, USA
| | - Alba Corman
- New York Genome Center, New York, NY, USA; Department of Biology, New York University, New York, NY, USA
| | - Alexandra Nikish
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Broad Institute, Cambridge, MA, USA
| | - Yang Zhou
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Montreal Neurological Institute, Montreal, QC, Canada
| | - Randy J Platt
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Ivan Iossifov
- New York Genome Center, New York, NY, USA; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Feng Zhang
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Broad Institute, Cambridge, MA, USA
| | - Jen Q Pan
- Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA, USA.
| | - Neville E Sanjana
- New York Genome Center, New York, NY, USA; Department of Biology, New York University, New York, NY, USA.
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11
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Huang X, Miyata H, Wang H, Mori G, Iida-Norita R, Ikawa M, Percudani R, Chung JJ. A CUG-initiated CATSPERθ functions in the CatSper channel assembly and serves as a checkpoint for flagellar trafficking. Proc Natl Acad Sci U S A 2023; 120:e2304409120. [PMID: 37725640 PMCID: PMC10523455 DOI: 10.1073/pnas.2304409120] [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: 03/16/2023] [Accepted: 08/10/2023] [Indexed: 09/21/2023] Open
Abstract
Calcium signaling is critical for successful fertilization. In spermatozoa, calcium influx into the sperm flagella mediated by the sperm-specific CatSper calcium channel is necessary for hyperactivated motility and male fertility. CatSper is a macromolecular complex and is repeatedly arranged in zigzag rows within four linear nanodomains along the sperm flagella. Here, we report that the Tmem249-encoded transmembrane (TM) domain-containing protein, CATSPERθ is essential for the CatSper channel assembly during sperm tail formation. CATSPERθ facilitates the channel assembly by serving as a scaffold for a pore-forming subunit CATSPER4. CATSPERθ is specifically localized at the interface of a CatSper dimer and can self-interact, suggesting its potential role in CatSper dimer formation. Male mice lacking CATSPERθ are infertile because the sperm lack the entire CatSper channel from sperm flagella, rendering sperm unable to hyperactivate, regardless of their normal expression in the testis. In contrast, genetic abrogation of any of the other CatSper TM subunits results in loss of CATSPERθ protein in the spermatid cells during spermatogenesis. CATSPERθ might act as a checkpoint for the properly assembled CatSper channel complex to traffic to sperm flagella. This study provides insights into the CatSper channel assembly and elucidates the physiological role of CATSPERθ in sperm motility and male fertility.
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Affiliation(s)
- Xiaofang Huang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT06510
| | - Haruhiko Miyata
- Research Institute for Microbial Diseases, Osaka University, Suita565-0871, Japan
| | - Huafeng Wang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT06510
| | - Giulia Mori
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma43124, Italy
| | - Rie Iida-Norita
- Research Institute for Microbial Diseases, Osaka University, Suita565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita565-0871, Japan
| | - Riccardo Percudani
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma43124, Italy
| | - Jean-Ju Chung
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT06510
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, Yale University, New Haven, CT06510
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12
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Varghese N, Moscoso B, Chavez A, Springer K, Ortiz E, Soh H, Santaniello S, Maheshwari A, Tzingounis AV. KCNQ2/3 Gain-of-Function Variants and Cell Excitability: Differential Effects in CA1 versus L2/3 Pyramidal Neurons. J Neurosci 2023; 43:6479-6494. [PMID: 37607817 PMCID: PMC10513074 DOI: 10.1523/jneurosci.0980-23.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/24/2023] Open
Abstract
Gain-of-function (GOF) pathogenic variants in the potassium channels KCNQ2 and KCNQ3 lead to hyperexcitability disorders such as epilepsy and autism spectrum disorders. However, the underlying cellular mechanisms of how these variants impair forebrain function are unclear. Here, we show that the R201C variant in KCNQ2 has opposite effects on the excitability of two types of mouse pyramidal neurons of either sex, causing hyperexcitability in layer 2/3 (L2/3) pyramidal neurons and hypoexcitability in CA1 pyramidal neurons. Similarly, the homologous R231C variant in KCNQ3 leads to hyperexcitability in L2/3 pyramidal neurons and hypoexcitability in CA1 pyramidal neurons. However, the effects of KCNQ3 gain-of-function on excitability are specific to superficial CA1 pyramidal neurons. These findings reveal a new level of complexity in the function of KCNQ2 and KCNQ3 channels in the forebrain and provide a framework for understanding the effects of gain-of-function variants and potassium channels in the brain.SIGNIFICANCE STATEMENT KCNQ2/3 gain-of-function (GOF) variants lead to severe forms of neurodevelopmental disorders, but the mechanisms by which these channels affect neuronal activity are poorly understood. In this study, using a series of transgenic mice we demonstrate that the same KCNQ2/3 GOF variants can lead to either hyperexcitability or hypoexcitability in different types of pyramidal neurons [CA1 vs layer (L)2/3]. Additionally, we show that expression of the recurrent KCNQ2 GOF variant R201C in forebrain pyramidal neurons could lead to seizures and SUDEP. Our data suggest that the effects of KCNQ2/3 GOF variants depend on specific cell types and brain regions, possibly accounting for the diverse range of phenotypes observed in individuals with KCNQ2/3 GOF variants.
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Affiliation(s)
- Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Bruno Moscoso
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Ana Chavez
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Erika Ortiz
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Sabato Santaniello
- Department of Biomedical Engineering and Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut 06269
| | - Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
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13
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Zeng Z, Xu Y, Zhou Y, Su R, Tao L, Wang Z, Chen C, Chen W. Prognostic Analysis of KCNQ2 Patients via Combining EEG Deep Features and Machine Learning Classifiers. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083766 DOI: 10.1109/embc40787.2023.10341098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Pathogenic variants of the KCNQ2 gene often induces neonatal epilepsy in clinical. For better treatment, infants with confirmed KCNQ2 pathogenic variant and epilepsy symptoms need to adjust their treatment plans according to the outcome after taking antiseizure medicines (ASMs). This process is often time-consuming and requires long-term follow-up, which undoubtedly causes unnecessary psychological and economic burdens. In this study, we investigate the feasibility to predict the outcome of KCNQ2 patients via Electroencephalogram (EEG). By using the combination of deep networks and classical classifiers, the abnormal brain pathological activities recorded in EEGs can be encoded into deep features and decoded into specific KCNQ2 outcomes, thus taking the advantage of both powerful feature extraction capability from deep networks and stronger classification ability from classical classifiers. Specifically, we acquire 10-channel EEG signals from 33 infants with KCNQ2 pathogenic variants after taking ASMs. Two well-trained models (Resnet-50 and Resnet-18) are employed to extract deep features from the EEG spectrums. We achieve an accuracy of 78.7% to predict the KCNQ2 outcome of each infant. To our best knowledge, this is the first study to employ potential EEG pathological differences to predict the outcomes of KCNQ2 patients. The investigation of automatic KCNQ2 outcome prediction may contribute to a more convenient diagnosis mechanism for KCNQ2 patients.
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14
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Oh H, Lee S, Oh Y, Kim S, Kim YS, Yang Y, Choi W, Yoo YE, Cho H, Lee S, Yang E, Koh W, Won W, Kim R, Lee CJ, Kim H, Kang H, Kim JY, Ku T, Paik SB, Kim E. Kv7/KCNQ potassium channels in cortical hyperexcitability and juvenile seizure-related death in Ank2-mutant mice. Nat Commun 2023; 14:3547. [PMID: 37321992 PMCID: PMC10272139 DOI: 10.1038/s41467-023-39203-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: 05/12/2022] [Accepted: 06/01/2023] [Indexed: 06/17/2023] Open
Abstract
Autism spectrum disorders (ASD) represent neurodevelopmental disorders characterized by social deficits, repetitive behaviors, and various comorbidities, including epilepsy. ANK2, which encodes a neuronal scaffolding protein, is frequently mutated in ASD, but its in vivo functions and disease-related mechanisms are largely unknown. Here, we report that mice with Ank2 knockout restricted to cortical and hippocampal excitatory neurons (Ank2-cKO mice) show ASD-related behavioral abnormalities and juvenile seizure-related death. Ank2-cKO cortical neurons show abnormally increased excitability and firing rate. These changes accompanied decreases in the total level and function of the Kv7.2/KCNQ2 and Kv7.3/KCNQ3 potassium channels and the density of these channels in the enlengthened axon initial segment. Importantly, the Kv7 agonist, retigabine, rescued neuronal excitability, juvenile seizure-related death, and hyperactivity in Ank2-cKO mice. These results suggest that Ank2 regulates neuronal excitability by regulating the length of and Kv7 density in the AIS and that Kv7 channelopathy is involved in Ank2-related brain dysfunctions.
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Affiliation(s)
- Hyoseon Oh
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Yusang Oh
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Korea
| | - Seongbin Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Young Seo Kim
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Yeji Yang
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, 162 Yeongudanjiro, Ochang, Cheongju, Chungbuk, 28119, Korea
| | - Woochul Choi
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Korea
| | - Ye-Eun Yoo
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Heejin Cho
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Seungjoon Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Esther Yang
- Department of Anatomy and Brain Korea 21 Graduate Program, Biomedical Science, College of Medicine, Korea University, Seoul, 02841, Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, IBS, Daejeon, 34126, Korea
| | - Woojin Won
- Center for Cognition and Sociality, IBS, Daejeon, 34126, Korea
| | - Ryunhee Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - C Justin Lee
- Center for Cognition and Sociality, IBS, Daejeon, 34126, Korea
| | - Hyun Kim
- Department of Anatomy and Brain Korea 21 Graduate Program, Biomedical Science, College of Medicine, Korea University, Seoul, 02841, Korea
| | - Hyojin Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information, Daejeon, 34141, Korea
| | - Jin Young Kim
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, 162 Yeongudanjiro, Ochang, Cheongju, Chungbuk, 28119, Korea
| | - Taeyun Ku
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Se-Bum Paik
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea.
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea.
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15
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Kapell H, Fazio L, Dyckow J, Schwarz S, Cruz-Herranz A, Mayer C, Campos J, D’Este E, Möbius W, Cordano C, Pröbstel AK, Gharagozloo M, Zulji A, Narayanan Naik V, Delank A, Cerina M, Müntefering T, Lerma-Martin C, Sonner JK, Sin JH, Disse P, Rychlik N, Sabeur K, Chavali M, Srivastava R, Heidenreich M, Fitzgerald KC, Seebohm G, Stadelmann C, Hemmer B, Platten M, Jentsch TJ, Engelhardt M, Budde T, Nave KA, Calabresi PA, Friese MA, Green AJ, Acuna C, Rowitch DH, Meuth SG, Schirmer L. Neuron-oligodendrocyte potassium shuttling at nodes of Ranvier protects against inflammatory demyelination. J Clin Invest 2023; 133:e164223. [PMID: 36719741 PMCID: PMC10065072 DOI: 10.1172/jci164223] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/27/2023] [Indexed: 02/01/2023] Open
Abstract
Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease of the CNS. Increasing evidence suggests that vulnerable neurons in MS exhibit fatal metabolic exhaustion over time, a phenomenon hypothesized to be caused by chronic hyperexcitability. Axonal Kv7 (outward-rectifying) and oligodendroglial Kir4.1 (inward-rectifying) potassium channels have important roles in regulating neuronal excitability at and around the nodes of Ranvier. Here, we studied the spatial and functional relationship between neuronal Kv7 and oligodendroglial Kir4.1 channels and assessed the transcriptional and functional signatures of cortical and retinal projection neurons under physiological and inflammatory demyelinating conditions. We found that both channels became dysregulated in MS and experimental autoimmune encephalomyelitis (EAE), with Kir4.1 channels being chronically downregulated and Kv7 channel subunits being transiently upregulated during inflammatory demyelination. Further, we observed that pharmacological Kv7 channel opening with retigabine reduced neuronal hyperexcitability in human and EAE neurons, improved clinical EAE signs, and rescued neuronal pathology in oligodendrocyte-Kir4.1-deficient (OL-Kir4.1-deficient) mice. In summary, our findings indicate that neuron-OL compensatory interactions promoted resilience through Kv7 and Kir4.1 channels and identify pharmacological activation of nodal Kv7 channels as a neuroprotective strategy against inflammatory demyelination.
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Affiliation(s)
- Hannah Kapell
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Luca Fazio
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
- Department of Neurology, University of Düsseldorf, Dusseldorf, Germany
| | - Julia Dyckow
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Sophia Schwarz
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Andrés Cruz-Herranz
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
| | - Christina Mayer
- Institute of Neuroimmunology and Multiple Sclerosis, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Joaquin Campos
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Elisa D’Este
- Optical Microscopy Facility, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Cluster of Excellence, “Multiscale Bioimaging: from Molecular Machines to Network of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Christian Cordano
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
| | - Anne-Katrin Pröbstel
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
- Neurologic Clinic and Policlinic and Research Center for Clinical Neuroimmunology and Neuroscience Basel, Departments of Medicine, Biomedicine, and Clinical Research, University Hospital of Basel, University of Basel, Basel, Switzerland
| | - Marjan Gharagozloo
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Amel Zulji
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Venu Narayanan Naik
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
| | - Anna Delank
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
| | - Manuela Cerina
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
| | | | - Celia Lerma-Martin
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Jana K. Sonner
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Jung Hyung Sin
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
| | - Paul Disse
- Institute for Genetics of Heart Diseases (IfGH), Cellular Electrophysiology and Molecular Biology, UKM, Münster, Germany
- University of Münster, Chembion, Münster, Germany
| | - Nicole Rychlik
- University of Münster, Chembion, Münster, Germany
- Institute of Physiology I, University of Münster, Münster, Germany
| | - Khalida Sabeur
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and
- Department of Pediatrics, UCSF, San Francisco, California, USA
| | - Manideep Chavali
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and
- Department of Pediatrics, UCSF, San Francisco, California, USA
| | - Rajneesh Srivastava
- Department of Neurology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Matthias Heidenreich
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Kathryn C. Fitzgerald
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Cellular Electrophysiology and Molecular Biology, UKM, Münster, Germany
| | - Christine Stadelmann
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Institute of Neuropathology, University Medical Center, Göttingen, Germany
| | - Bernhard Hemmer
- Department of Neurology, School of Medicine, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology, Munich, Germany
| | - Michael Platten
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- DKTK Clinical Cooperation Unit Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center (DKFZ), INF 280, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN) and
- Mannheim Center for Translational Neuroscience and Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
- Neurocure Cluster of Excellence, Charité University Medicine Berlin, Berlin, Germany
| | - Maren Engelhardt
- Mannheim Center for Translational Neuroscience and Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Institute of Neuroanatomy, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Institute of Anatomy and Cell Biology, Johannes Kepler University Linz, Linz, Austria
| | - Thomas Budde
- Institute of Physiology I, University of Münster, Münster, Germany
| | - Klaus-Armin Nave
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Peter A. Calabresi
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Manuel A. Friese
- Institute of Neuroimmunology and Multiple Sclerosis, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Ari J. Green
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
- Department of Ophthalmology, UCSF, San Francisco, California, USA
| | - Claudio Acuna
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - David H. Rowitch
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and
- Department of Pediatrics, UCSF, San Francisco, California, USA
- Wellcome Trust–Medical Research Council Stem Cell Institute and
- Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom
- Department of Neurosurgery, UCSF, San Francisco, California, USA
| | - Sven G. Meuth
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
- Department of Neurology, University of Düsseldorf, Dusseldorf, Germany
| | - Lucas Schirmer
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN) and
- Mannheim Center for Translational Neuroscience and Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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16
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Huang X, Miyata H, Wang H, Mori G, Iida-Norita R, Ikawa M, Percudani R, Chung JJ. A CUG-initiated CATSPERθ functions in the CatSper channel assembly and serves as a checkpoint for flagellar trafficking. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.532952. [PMID: 36993167 PMCID: PMC10055175 DOI: 10.1101/2023.03.17.532952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Calcium signaling is critical for successful fertilization. In spermatozoa, calcium influx into the sperm flagella mediated by the sperm specific CatSper calcium channel is necessary for hyperactivated motility and male fertility. CatSper is a macromolecular complex and is repeatedly arranged in zigzag rows within four linear nanodomains along the sperm flagella. Here, we report that the Tmem249 -encoded transmembrane domain containing protein, CATSPERθ, is essential for the CatSper channel assembly during sperm tail formation. CATSPERθ facilitates the channel assembly by serving as a scaffold for a pore forming subunit CATSPER4. CATSPERθ is specifically localized at the interface of a CatSper dimer and can self-interact, suggesting its potential role in CatSper dimer formation. Male mice lacking CATSPERθ are infertile because the sperm lack the entire CatSper channel from sperm flagella, rendering sperm unable to hyperactivate, regardless of their normal expression in the testis. In contrast, genetic abrogation of any of the other CatSper transmembrane subunits results in loss of CATSPERθ protein in the spermatid cells during spermatogenesis. CATSPERθ might acts as a checkpoint for the properly assembled CatSper channel complex to traffic to sperm flagella. This study provides insights into the CatSper channel assembly and elucidates the physiological role of CATSPERθ in sperm motility and male fertility.
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Affiliation(s)
- Xiaofang Huang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, 06510, USA
| | - Haruhiko Miyata
- Research Institute for Microbial Diseases, Osaka University, Suita 5650871, Japan
| | - Huafeng Wang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, 06510, USA
| | - Giulia Mori
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma 43124, Italy
| | - Rie Iida-Norita
- Research Institute for Microbial Diseases, Osaka University, Suita 5650871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita 5650871, Japan
| | - Riccardo Percudani
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma 43124, Italy
| | - Jean-Ju Chung
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, 06510, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, Yale University, New Haven, CT, 06510
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17
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Potassium channelopathies associated with epilepsy-related syndromes and directions for therapeutic intervention. Biochem Pharmacol 2023; 208:115413. [PMID: 36646291 DOI: 10.1016/j.bcp.2023.115413] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
A number of mutations to members of several CNS potassium (K) channel families have been identified which result in rare forms of neonatal onset epilepsy, or syndromes of which one prominent characteristic is a form of epilepsy. Benign Familial Neonatal Convulsions or Seizures (BFNC or BFNS), also referred to as Self-Limited Familial Neonatal Epilepsy (SeLNE), results from mutations in 2 members of the KV7 family (KCNQ) of K channels; while generally self-resolving by about 15 weeks of age, these mutations significantly increase the probability of generalized seizure disorders in the adult, in some cases they result in more severe developmental syndromes. Epilepsy of Infancy with Migrating Focal Seizures (EIMSF), or Migrating Partial Seizures of Infancy (MMPSI), is a rare severe form of epilepsy linked primarily to gain of function mutations in a member of the sodium-dependent K channel family, KCNT1 or SLACK. Finally, KCNMA1 channelopathies, including Liang-Wang syndrome (LIWAS), are rare combinations of neurological symptoms including seizure, movement abnormalities, delayed development and intellectual disabilities, with Liang-Wang syndrome an extremely serious polymalformative syndrome with a number of neurological sequelae including epilepsy. These are caused by mutations in the pore-forming subunit of the large-conductance calcium-activated K channel (BK channel) KCNMA1. The identification of these rare but significant channelopathies has resulted in a resurgence of interest in their treatment by direct pharmacological or genetic modulation. We will briefly review the genetics, biophysics and pharmacology of these K channels, their linkage with the 3 syndromes described above, and efforts to more effectively target these syndromes.
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18
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Tonomura S, Gu JG. Saltatory conduction and intrinsic electrophysiological properties at the nodes of ranvier of Aα/β-afferent fibers and Aα-efferent fibers in rat sciatic nerves. Mol Pain 2023; 19:17448069231187366. [PMID: 37369680 PMCID: PMC10413906 DOI: 10.1177/17448069231187366] [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: 05/05/2023] [Revised: 06/05/2023] [Accepted: 06/23/2023] [Indexed: 06/29/2023] Open
Abstract
Large-diameter myelinated fibers in sciatic nerves are composed of both Aα/β-afferent fibers and Aα-efferent fibers to convey sensory and motor impulses, respectively, via saltatory conduction for rapid leg responses. Saltatory conduction and electrophysiological properties at the nodes of Ranvier (NRs) of these sciatic nerve fibers have not been directly studied. We used ex vivo sciatic nerve preparations from rats and applied patch-clamp recordings at the NRs of both Aα/β-afferent fibers and Aα-efferent fibers in the sciatic nerves to characterize their saltatory conduction and intrinsic electrophysiological properties. The velocity and frequency of saltatory conduction in both types of fibers were similar. Resting membrane potentials (RMPs), input resistance, action potential (AP) threshold, and AP rheobase were also not significantly different at the NRs of the two types of fibers in the sciatic nerves. In comparison with Aα/β-afferent fibers, Aα-efferent fibers in the sciatic nerves show higher amplitude and broader width of APs at their NRs. At the NRs of both types of fibers, depolarizing voltages evoked transient inward currents followed by non-inactivating outward currents, and the inward currents and non-inactivating outward currents at the NRs were not significantly different between the two types of fibers. Using AP-clamp, inward currents during AP upstroke were found to be insignificant difference, but amplitudes of non-inactivating outward currents during AP repolarization were significantly lower at the NRs of Aα-efferent fibers than at the NRs of Aα/β-afferent fibers in the sciatic nerves. Collectively, saltatory conduction, ionic currents, and intrinsic electrophysiological properties at the NRs of Aα/β-afferent fibers and Aα-efferent fibers in the sciatic nerves are generally similar, but some differences were also observed.
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Affiliation(s)
- Sotatsu Tonomura
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama, Birmingham, AL, USA
| | - Jianguo G Gu
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama, Birmingham, AL, USA
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19
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Abad-Rodríguez J, Brocca ME, Higuero AM. Glycans and Carbohydrate-Binding/Transforming Proteins in Axon Physiology. ADVANCES IN NEUROBIOLOGY 2023; 29:185-217. [PMID: 36255676 DOI: 10.1007/978-3-031-12390-0_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The mature nervous system relies on the polarized morphology of neurons for a directed flow of information. These highly polarized cells use their somatodendritic domain to receive and integrate input signals while the axon is responsible for the propagation and transmission of the output signal. However, the axon must perform different functions throughout development before being fully functional for the transmission of information in the form of electrical signals. During the development of the nervous system, axons perform environmental sensing functions, which allow them to navigate through other regions until a final target is reached. Some axons must also establish a regulated contact with other cells before reaching maturity, such as with myelinating glial cells in the case of myelinated axons. Mature axons must then acquire the structural and functional characteristics that allow them to perform their role as part of the information processing and transmitting unit that is the neuron. Finally, in the event of an injury to the nervous system, damaged axons must try to reacquire some of their immature characteristics in a regeneration attempt, which is mostly successful in the PNS but fails in the CNS. Throughout all these steps, glycans perform functions of the outermost importance. Glycans expressed by the axon, as well as by their surrounding environment and contacting cells, encode key information, which is fine-tuned by glycan modifying enzymes and decoded by glycan binding proteins so that the development, guidance, myelination, and electrical transmission functions can be reliably performed. In this chapter, we will provide illustrative examples of how glycans and their binding/transforming proteins code and decode instructive information necessary for fundamental processes in axon physiology.
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Affiliation(s)
- José Abad-Rodríguez
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain.
| | - María Elvira Brocca
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
| | - Alonso Miguel Higuero
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
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20
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Tanner GR, Tzingounis AV. The mammalian nodal action potential: new data bring new perspectives. ADVANCES IN PHYSIOLOGY EDUCATION 2022; 46:693-702. [PMID: 36173340 DOI: 10.1152/advan.00171.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Since its discovery in the mid-20th century, the Hodgkin-Huxley biophysical model of the squid giant axon's (SGA's) neurophysiology has traditionally served as the basis for the teaching of action potential (AP) dynamics in the physiology classroom. This model teaches that leak conductances set membrane resting potential; that fast, inactivating, voltage-gated sodium channels effect the SGA AP upstroke; and that delayed, rectifying, noninactivating voltage-gated potassium channels carry AP repolarization and the early part of the afterhyperpolarization (AHP). This model serves well to introduce students to the fundamental ideas of resting potential establishment and maintenance, as well as basic principles of AP generation and propagation. Furthermore, the Hodgkin-Huxley SGA model represents an excellent and accessible starting point for discussion of the concept of AP threshold and the role of passive electrical properties of the neuron. Additionally, the introduction of the Hodgkin-Huxley model of the SGA AP permits the integration of physiological principles, as instructors ask students to apply previously studied principles of transporter and channel biophysics to the essential physiological phenomenon of electrical signal conduction. However, both some early observations as well as more recent evidence strongly suggest that this seminal invertebrate model of AP dynamics does not appropriately capture the full story for mammalian axons. We review recent evidence that mammalian axonal nodes of Ranvier repolarize largely (though not exclusively) through the activity of leak potassium-ion (K+) conductances carried through two-pore domain (K2P) channels. We call for changes to physiology textbooks and curricula to highlight this remarkable difference in invertebrate and mammalian AP repolarization mechanisms.NEW & NOTEWORTHY Historically, physiology courses have typically taught that action potential repolarization occurs exclusively due to the activation of delayed-rectifier voltage-gated potassium channels. Here, we review and highlight recent evidence that leak potassium channels of the two-pore domain (K2P) class may largely serve this repolarization role at mammalian nodes of Ranvier. We call for the inclusion of these ideas in physiology curricula at all levels, from high school to graduate school.
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Affiliation(s)
- Geoffrey R Tanner
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut
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21
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Alqahtani AR, Badry A, Abd Al Galil FM, Amr ZS. Morphometric and meristic diversity of the species Androctonus crassicauda (Olivier, 1807) (Scorpiones: Buthidae) in Saudi Arabia. PeerJ 2022; 10:e14198. [PMID: 36281363 PMCID: PMC9587716 DOI: 10.7717/peerj.14198] [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: 07/19/2022] [Accepted: 09/16/2022] [Indexed: 01/24/2023] Open
Abstract
Intraspecific molecular and morphological variations among geographically isolated populations are useful for understanding the evolutionary processes, which is considered early stage of allopatric speciation. Also, the knowledge of the regional variation of scorpion venom composition is needed to improve antivenom therapeutic management. Androctonus crassicauda (Olivier, 1807) is the most common and medically important species in Arabia and the Middle East. Therefore, this study aimed to investigate the geographic morphological variation among A.crassicaudapopulations, regarding its geographical distribution in unexplored arid regions in Saudi Arabia. Samples were collected and examined morphologically under a dissecting microscope from different four eco-geographical regions. The results of ANOVA and multivariate statistical analyses provide strong evidence of geographical variation. The two populations from OTU3 and OUT4 showed the greatest degree of morphological difference from populations of OUT1 and OUT2. Each OTU3 and OTU4 populations showed significant speciation without overlapping in the two groups, while the remaining overlapped groups comprised two other populations. Several body variables influenced male separation, including carapace posterior width, metasoma 3rd length, and metasoma 2nd length. For females, telson length, metasoma 1st width, and sternite 7th width were highly influential variables. Such variation may suggest the existence of cryptic taxa within A. crassicauda populations in Saudi Arabia. Moreover, metasoma ratios can be used as good indicators in intraspecific variation studies of Scorpions.
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Affiliation(s)
| | - Ahmed Badry
- Department of Zoology, Faculty of Science (Boys), Al-Azhar University, Cairo, Egypt
| | - Fahd Mohammed Abd Al Galil
- Department of Biology, College of Science, University of Bisha, Bisha, Saudi Arabia,Department of Biology, Faculty of Applied Sciences, Thamar University, Thamar, Yemen
| | - Zuhair S. Amr
- Department of Biology, Jordan University of Science and Technology, Jordan, Jordan
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22
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Gao K, Lin Z, Wen S, Jiang Y. Potassium channels and epilepsy. Acta Neurol Scand 2022; 146:699-707. [PMID: 36225112 DOI: 10.1111/ane.13695] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/16/2022] [Indexed: 01/10/2023]
Abstract
With the development and application of next-generation sequencing technology, the aetiological diagnosis of genetic epilepsy is rapidly becoming easier and less expensive. Additionally, there is a growing body of research into precision therapy based on genetic diagnosis. The numerous genes in the potassium ion channel family constitute the largest family of ion channels: this family is divided into different subtypes. Potassium ion channels play a crucial role in the electrical activity of neurons and are directly involved in the mechanism of epileptic seizures. In China, scientific research on genetic diagnosis and studies of precision therapy for genetic epilepsy are progressing rapidly. Many cases of epilepsy caused by mutation of potassium channel genes have been identified, and several potassium channel gene targets and drug candidates have been discovered. The purpose of this review is to briefly summarize the progress of research on the precise diagnosis and treatment of potassium ion channel-related genetic epilepsy, especially the research conducted in China. Here in, we review several large cohort studies on the genetic diagnosis of epilepsy in China in recent years, summarized the proportion of potassium channel genes. We focus on the progress of precison therapy on some hot epilepsy related potassium channel genes: KCNA1, KCNA2, KCNB1, KCNC1, KCND2, KCNQ2, KCNQ3, KCNMA1, and KCNT1.
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Affiliation(s)
- Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Zehong Lin
- Department of Neurology, Affiliated Children's Hospital of Capital Institute of Pediatrics, Beijing, China
| | - Sijia Wen
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
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23
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Ogata G, Partida GJ, Fasoli A, Ishida AT. Calcium/calmodulin-dependent protein kinase II associates with the K + channel isoform Kv4.3 in adult rat optic nerve. Front Neuroanat 2022; 16:958986. [PMID: 36172564 PMCID: PMC9512010 DOI: 10.3389/fnana.2022.958986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022] Open
Abstract
Spikes are said to exhibit "memory" in that they can be altered by spikes that precede them. In retinal ganglion cell axons, for example, rapid spiking can slow the propagation of subsequent spikes. This increases inter-spike interval and, thus, low-pass filters instantaneous spike frequency. Similarly, a K+ ion channel blocker (4-aminopyridine, 4AP) increases the time-to-peak of compound action potentials recorded from optic nerve, and we recently found that reducing autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) does too. These results would be expected if CaMKII modulates spike propagation by regulating 4AP-sensitive K+ channels. As steps toward identifying a possible substrate, we test whether (i) 4AP alters optic nerve spike shape in ways consistent with reducing K+ current, (ii) 4AP alters spike propagation consistent with effects of reducing CaMKII activation, (iii) antibodies directed against 4AP-sensitive and CaMKII-regulated K+ channels bind to optic nerve axons, and (iv) optic nerve CaMKII co-immunoprecipitates with 4AP-sensitive K+ channels. We find that, in adult rat optic nerve, (i) 4AP selectively slows spike repolarization, (ii) 4AP slows spike propagation, (iii) immunogen-blockable staining is achieved with anti-Kv4.3 antibodies but not with antibodies directed against Kv1.4 or Kv4.2, and (iv) CaMKII associates with Kv4.3. Kv4.3 may thus be a substrate that underlies activity-dependent spike regulation in adult visual system pathways.
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Affiliation(s)
- Genki Ogata
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA, United States
| | - Gloria J. Partida
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA, United States
| | - Anna Fasoli
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA, United States
| | - Andrew T. Ishida
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA, United States
- Department of Ophthalmology and Vision Science, University of California, Sacramento, Sacramento, CA, United States
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24
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Jing J, Dunbar C, Sonesra A, Chavez A, Park S, Yang R, Soh H, Lee M, Tzingounis AV, Cooper EC, Jiang X, Maheshwari A. Removal of KCNQ2 from parvalbumin-expressing interneurons improves anti-seizure efficacy of retigabine. Exp Neurol 2022; 355:114141. [PMID: 35691372 PMCID: PMC9899633 DOI: 10.1016/j.expneurol.2022.114141] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/18/2022] [Accepted: 06/06/2022] [Indexed: 02/07/2023]
Abstract
Anti-seizure drug (ASD) targets are widely expressed in both excitatory and inhibitory neurons. It remains unknown if the action of an ASD upon inhibitory neurons could counteract its beneficial effects on excitatory neurons (or vice versa), thereby reducing the efficacy of the ASD. Here, we examine whether the efficacy of the ASD retigabine (RTG) is altered after removal of the Kv7 potassium channel subunit KCNQ2, one of its drug targets, from parvalbumin-expressing interneurons (PV-INs). Parvalbumin-Cre (PV-Cre) mice were crossed with Kcnq2-floxed (Kcnq2fl/fl) mice to conditionally delete Kcnq2 from PV-INs. In these conditional knockout mice (cKO, PV-Kcnq2fl/fl), RTG (10 mg/kg, i.p.) significantly delayed the onset of either picrotoxin (PTX, 10 mg/kg, i.p)- or kainic acid (KA, 30 mg/kg, i.p.)-induced convulsive seizures compared to vehicle, while RTG was not effective in wild-type littermates (WT). Immunostaining for KCNQ2 and KCNQ3 revealed that both subunits were enriched at axon initial segments (AISs) of hippocampal CA1 PV-INs, and their specific expression was selectively abolished in cKO mice. Accordingly, the M-currents recorded from CA1 PV-INs and their sensitivity to RTG were significantly reduced in cKO mice. While the ability of RTG to suppress CA1 excitatory neurons in hippocampal slices was unchanged in cKO mice, its suppressive effect on the spike activity of CA1 PV-INs was significantly reduced compared with WT mice. In addition, the RTG-induced suppression on intrinsic membrane excitability of PV-INs in WT mice was significantly reduced in cKO mice. These findings suggest that preventing RTG from suppressing PV-INs improves its anticonvulsant effect.
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Affiliation(s)
- Junzhan Jing
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Street, Houston, TX 77030, United States of America
| | - Corrinne Dunbar
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Alina Sonesra
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Ana Chavez
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Suhyeorn Park
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Ryan Yang
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Rd, Storrs, CT 06269, United States of America
| | - Maxwell Lee
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Rd, Storrs, CT 06269, United States of America
| | - Edward C Cooper
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Street, Houston, TX 77030, United States of America.
| | - Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America.
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25
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Neurons: The Interplay between Cytoskeleton, Ion Channels/Transporters and Mitochondria. Cells 2022; 11:cells11162499. [PMID: 36010576 PMCID: PMC9406945 DOI: 10.3390/cells11162499] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/06/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022] Open
Abstract
Neurons are permanent cells whose key feature is information transmission via chemical and electrical signals. Therefore, a finely tuned homeostasis is necessary to maintain function and preserve neuronal lifelong survival. The cytoskeleton, and in particular microtubules, are far from being inert actors in the maintenance of this complex cellular equilibrium, and they participate in the mobilization of molecular cargos and organelles, thus influencing neuronal migration, neuritis growth and synaptic transmission. Notably, alterations of cytoskeletal dynamics have been linked to alterations of neuronal excitability. In this review, we discuss the characteristics of the neuronal cytoskeleton and provide insights into alterations of this component leading to human diseases, addressing how these might affect excitability/synaptic activity, as well as neuronal functioning. We also provide an overview of the microscopic approaches to visualize and assess the cytoskeleton, with a specific focus on mitochondrial trafficking.
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26
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Sleutjes BTHM, Stikvoort García DJL, Kovalchuk MO, Heuberger JAAC, Groeneveld GJ, Franssen H, van den Berg LH. Acute retigabine-induced effects on myelinated motor axons in amyotrophic lateral sclerosis. Pharmacol Res Perspect 2022; 10:e00983. [PMID: 35881020 PMCID: PMC9318643 DOI: 10.1002/prp2.983] [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: 12/22/2021] [Revised: 06/11/2022] [Accepted: 06/15/2022] [Indexed: 11/24/2022] Open
Abstract
Altered motor neuron excitability in patients with amyotrophic lateral sclerosis (ALS) has been suggested to be an early pathophysiological mechanism associated with motor neuron death. Compounds that affect membrane excitability may therefore have disease‐modifying effects. Through which mechanism(s), these compounds modulate membrane excitability is mostly provided by preclinical studies, yet remains challenging to verify in clinical studies. Here, we investigated how retigabine affects human myelinated motor axons by applying computational modeling to interpret the complex excitability changes in a recent trial involving 18 ALS patients. Compared to baseline, the post‐dose excitability differences were modeled well by a hyperpolarizing shift of the half‐activation potential of slow potassium (K+)‐channels (till 2 mV). These findings verify that retigabine targets slow K+‐channel gating and highlight the usefulness of computational models. Further developments of this approach may facilitate the identification of early target engagement and ultimately aid selecting responders leading to more personalized treatment strategies.
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Affiliation(s)
- Boudewijn T H M Sleutjes
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Maria O Kovalchuk
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | - Hessel Franssen
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
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27
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Tonomura S, Ling J, Gu JG. Function of KCNQ2 channels at nodes of Ranvier of lumbar spinal ventral nerves of rats. Mol Brain 2022; 15:64. [PMID: 35858950 PMCID: PMC9297653 DOI: 10.1186/s13041-022-00949-0] [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: 06/01/2022] [Accepted: 07/07/2022] [Indexed: 11/28/2022] Open
Abstract
Previous immunohistochemical studies have shown the expression of KCNQ2 channels at nodes of Ranvier (NRs) of myelinated nerves. However, functions of these channels at NRs remain elusive. In the present study, we addressed this issue by directly applying whole-cell patch-clamp recordings at NRs of rat lumbar spinal ventral nerves in ex vivo preparations. We show that depolarizing voltages evoke large non-inactivating outward currents at NRs, which are partially inhibited by KCNQ channel blocker linopirdine and potentiated by KCNQ channel activator retigabine. Furthermore, linopirdine significantly alters intrinsic electrophysiological properties of NRs to depolarize resting membrane potential, increase input resistance, prolong AP width, reduce AP threshold, and decrease AP amplitude. On the other hand, retigabine significantly decreases input resistance and increases AP rheobase at NRs. Moreover, linopirdine increases excitability at NRs by converting single AP firing into multiple AP firing at many NRs. Saltatory conduction velocity is significantly reduced by retigabine, and AP success rate at high stimulation frequency is significantly increased by linopirdine. Collectively, KCNQ2 channels play a significant role in regulating intrinsic electrophysiological properties and saltatory conduction at NRs of motor nerve fibers of rats. These findings may provide insights into how the loss-of-function mutation in KCNQ2 channels can lead to neuromuscular disorders in human patients.
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Affiliation(s)
- Sotatsu Tonomura
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jennifer Ling
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jianguo G Gu
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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Gorlewicz A, Barthet G, Zucca S, Vincent P, Griguoli M, Grosjean N, Wilczynski G, Mulle C. The Deletion of GluK2 Alters Cholinergic Control of Neuronal Excitability. Cereb Cortex 2022; 32:2907-2923. [PMID: 34730179 DOI: 10.1093/cercor/bhab390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/14/2022] Open
Abstract
Kainate receptors (KARs) are key regulators of synaptic circuits by acting at pre- and postsynaptic sites through either ionotropic or metabotropic actions. KARs can be activated by kainate, a potent neurotoxin, which induces acute convulsions. Here, we report that the acute convulsive effect of kainate mostly depends on GluK2/GluK5 containing KARs. By contrast, the acute convulsive activity of pilocarpine and pentylenetetrazol is not alleviated in the absence of KARs. Unexpectedly, the genetic inactivation of GluK2 rather confers increased susceptibility to acute pilocarpine-induced seizures. The mechanism involves an enhanced excitability of GluK2-/- CA3 pyramidal cells compared with controls upon pilocarpine application. Finally, we uncover that the absence of GluK2 increases pilocarpine modulation of Kv7/M currents. Taken together, our findings reveal that GluK2-containing KARs can control the excitability of hippocampal circuits through interaction with the neuromodulatory cholinergic system.
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Affiliation(s)
- Adam Gorlewicz
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Gael Barthet
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Stefano Zucca
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Peggy Vincent
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Marilena Griguoli
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Noëlle Grosjean
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Grzegorz Wilczynski
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
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29
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Role of Voltage-Gated K + Channels and K2P Channels in Intrinsic Electrophysiological Properties and Saltatory Conduction at Nodes of Ranvier of Rat Lumbar Spinal Ventral Nerves. J Neurosci 2022; 42:4980-4994. [PMID: 35606142 PMCID: PMC9233441 DOI: 10.1523/jneurosci.0514-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/02/2022] [Accepted: 05/17/2022] [Indexed: 12/24/2022] Open
Abstract
Ion channels at the nodes of Ranvier (NRs) are believed to play essential roles in intrinsic electrophysiological properties and saltatory conduction of action potentials (AP) at the NRs of myelinated nerves. While we have recently shown that two-pore domain potassium (K2P) channels play a key role at the NRs of Aβ-afferent nerves, K+ channels and their functions at the NRs of mammalian motor nerves remain elusive. Here we addressed this issue by using ex vivo preparations of lumbar spinal ventral nerves from both male and female rats and the pressure-patch-clamp recordings at their NRs. We found that depolarizing voltages evoked large noninactivating outward currents at NRs. The outward currents could be partially inhibited by voltage-gated K+ channel blockers, largely inhibited by K2P blockers and cooling temperatures. Inhibition of the outward currents by voltage-gated K+ channel blockers, K2P blockers, or cooling temperatures significantly altered electrophysiological properties measured at the NRs, including resting membrane potential, input resistance, AP width, AP amplitude, AP threshold, and AP rheobase. Furthermore, K2P blockers and cooling temperatures significantly reduced saltatory conduction velocity and success rates of APs in response to high-frequency stimulation. Voltage-gated K+ channel blockers reduced AP success rates at high-frequency stimulation without significantly affecting saltatory conduction velocity. Collectively, both K2P and voltage-gated K+ channels play significant roles in intrinsic electrophysiological properties and saltatory conduction at NRs of motor nerve fibers of rats. The effects of cooling temperatures on saltatory conduction are at least partially mediated by K2P channels at the NRs.SIGNIFICANCE STATEMENT Ion channels localized at the NRs are believed to be key determinants of saltatory conduction on myelinated nerves. However, ion channels and their functions at the NRs have not been fully studied in different types of mammalian myelinated nerves. Here we use the pressure-patch-clamp recordings to show that both K2P and voltage-gated K+ channels play significant roles in intrinsic electrophysiological properties and saltatory conduction at NRs of lumbar spinal ventral nerves of rats. Furthermore, cooling temperatures exert effects on saltatory conduction via inhibition of ion channels at the NRs. Our results provide new insights into saltatory conduction on myelinated nerves and may have physiological as well as pathologic implications.
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30
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Singh SP, William M, Malavia M, Chu XP. Behavior of KCNQ Channels in Neural Plasticity and Motor Disorders. MEMBRANES 2022; 12:membranes12050499. [PMID: 35629827 PMCID: PMC9143857 DOI: 10.3390/membranes12050499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/26/2022] [Accepted: 05/03/2022] [Indexed: 02/01/2023]
Abstract
The broad distribution of voltage-gated potassium channels (VGKCs) in the human body makes them a critical component for the study of physiological and pathological function. Within the KCNQ family of VGKCs, these aqueous conduits serve an array of critical roles in homeostasis, especially in neural tissue. Moreover, the greater emphasis on genomic identification in the past century has led to a growth in literature on the role of the ion channels in pathological disease as well. Despite this, there is a need to consolidate the updated findings regarding both the pharmacotherapeutic and pathological roles of KCNQ channels, especially regarding neural plasticity and motor disorders which have the largest body of literature on this channel. Specifically, KCNQ channels serve a remarkable role in modulating the synaptic efficiency required to create appropriate plasticity in the brain. This role can serve as a foundation for clinical approaches to chronic pain. Additionally, KCNQ channels in motor disorders have been utilized as a direction for contemporary pharmacotherapeutic developments due to the muscarinic properties of this channel. The aim of this study is to provide a contemporary review of the behavior of these channels in neural plasticity and motor disorders. Upon review, the behavior of these channels is largely dependent on the physiological role that KCNQ modulatory factors (i.e., pharmacotherapeutic options) serve in pathological diseases.
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31
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Biba N, Becq H, Pallesi-Pocachard E, Sarno S, Granjeaud S, Montheil A, Kurz M, Villard L, Milh M, Santini PPL, Aniksztejn L. Time-limited alterations in cortical activity of a knock-in mice model of KCNQ2-related developmental and epileptic encephalopathy. J Physiol 2022; 600:2429-2460. [PMID: 35389519 DOI: 10.1113/jp282536] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 03/10/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The electrophysiological impact of the pathogenic c.821C>T mutation of the KCNQ2 gene (p.T274M variant in Kv7.2 subunit) related to Developmental and Epileptic Encephalopathy has been analyzed both in vivo and ex-vivo in layers II/III and V of motor cortical slice from a knock-in mice model during development at neonatal, post-weaning and juvenile stages. M current density and conductance are decreased and excitability of layers II/III pyramidal cells is increased in slices from neonatal and post-weaning KI mice but not from juvenile KI mice. M current and excitability of layer V pyramidal cells are impacted in KI mice only at post-weaning stage. Spontaneous GABAergic network-driven events are recorded until post-weaning stage and their frequency are increased in layers II/III of the KI mice. KI mice displayed spontaneous seizures preferentially at post-weaning rather than at juvenile stages. ABSTRACT De novo missense variants in the KCNQ2 gene encoding the Kv7.2 subunit of the voltage-gated potassium Kv7/M channels are the main cause of Developmental and Epileptic Encephalopathy (DEE) with neonatal onset. While seizures usually resolve during development, cognitive/motor deficits persist. To better understand the cellular mechanisms underlying network dysfunction and their progression over time, we investigated in vivo, using local field potential recordings of freely moving animals, and ex-vivo in layers II/III and V of motor cortical slices, using patch-clamp recordings, the electrophysiological properties of pyramidal cells from a heterozygous knock-in (KI) mouse model carrying the Kv7.2 p.T274M pathogenic variant during neonatal, post-weaning and juvenile developmental stages. We found that KI mice displayed spontaneous seizures preferentially at post-weaning rather than at juvenile stages. At the cellular level, the variant led to a reduction in M current density/conductance and to neuronal hyperexcitability. These alterations were observed during the neonatal period in pyramidal cells of layers II /III and during post-weaning stage in pyramidal cells of layer V. Moreover, there was an increase in the frequency of spontaneous network driven events mediated by GABA receptors suggesting that the excitability of interneurons was also increased. However, all these alterations were no more observed in layers II/III and V of juvenile mice. Thus, our data indicate that the action of the variant is developmentally regulated. This raises the possibility that the age related seizure remission observed in KCNQ2-related DEE patient results from a time limited alteration of Kv7 channels activity and neuronal excitability. Abstract figure legend Knock-in mice harboring the heterozygous pathogenic p.T274M variant in the Kv7.2 subunit (c.821C>T mutation of the KCNQ2 gene) related to Developmental and Epileptic Encephalopathy displayed epileptic seizures preferentially at post-weaning rather than at juvenile developmental stages. At cellular level, in motor cortical slices the variant led to a reduction in M current density, to a hyperexcitability of pyramidal cells and to an increase in the frequency of spontaneous network driven events mediated by GABA receptors. All these alterations are time limited and are observed in pyramidal cells of neonatal mice until post-weaning but not of juvenile mice in which the pyramidal cells have electrophysiological properties similar to those of wild-type mice. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Najoua Biba
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
| | - Hélène Becq
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
| | - Emilie Pallesi-Pocachard
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
| | - Stefania Sarno
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
| | - Samuel Granjeaud
- Centre de Recherche en Cancérologie de Marseille, INSERM, U1068, Institut Paoli Calmettes, CNRS, UMR7258, Aix-Marseille University UM 105, Marseille, France
| | - Aurélie Montheil
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
| | - Marie Kurz
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
| | - Laurent Villard
- Aix-Marseille University, INSERM, MMG, Marseille, France.,Department of Medical Genetics, La Timone Childrens's Hospital, Marseille, France
| | - Mathieu Milh
- Aix-Marseille University, INSERM, MMG, Marseille, France.,Department of Pediatric Neurology, La Timone Children's Hospital, Marseille, France
| | | | - Laurent Aniksztejn
- INSERM, INMED (U1249), Aix-Marseille University, Turing centre for living system, Marseille, France
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32
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Dixon RE, Navedo MF, Binder MD, Santana LF. Mechanisms and Physiological Implications of Cooperative Gating of Ion Channels Clusters. Physiol Rev 2021; 102:1159-1210. [PMID: 34927454 DOI: 10.1152/physrev.00022.2021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ion channels play a central role in the regulation of nearly every cellular process. Dating back to the classic 1952 Hodgkin-Huxley model of the generation of the action potential, ion channels have always been thought of as independent agents. A myriad of recent experimental findings exploiting advances in electrophysiology, structural biology, and imaging techniques, however, have posed a serious challenge to this long-held axiom as several classes of ion channels appear to open and close in a coordinated, cooperative manner. Ion channel cooperativity ranges from variable-sized oligomeric cooperative gating in voltage-gated, dihydropyridine-sensitive Cav1.2 and Cav1.3 channels to obligatory dimeric assembly and gating of voltage-gated Nav1.5 channels. Potassium channels, transient receptor potential channels, hyperpolarization cyclic nucleotide-activated channels, ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3Rs) have also been shown to gate cooperatively. The implications of cooperative gating of these ion channels range from fine tuning excitation-contraction coupling in muscle cells to regulating cardiac function and vascular tone, to modulation of action potential and conduction velocity in neurons and cardiac cells, and to control of pace-making activity in the heart. In this review, we discuss the mechanisms leading to cooperative gating of ion channels, their physiological consequences and how alterations in cooperative gating of ion channels may induce a range of clinically significant pathologies.
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Affiliation(s)
- Rose Ellen Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, United States
| | - Marc D Binder
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
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33
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Posttranscriptional modulation of KCNQ2 gene expression by the miR-106b microRNA family. Proc Natl Acad Sci U S A 2021; 118:2110200118. [PMID: 34785595 DOI: 10.1073/pnas.2110200118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) have recently emerged as important regulators of ion channel expression. We show here that select miR-106b family members repress the expression of the KCNQ2 K+ channel protein by binding to the 3'-untranslated region of KCNQ2 messenger RNA. During the first few weeks after birth, the expression of miR-106b family members rapidly decreases, whereas KCNQ2 protein level inversely increases. Overexpression of miR-106b mimics resulted in a reduction in KCNQ2 protein levels. Conversely, KCNQ2 levels were up-regulated in neurons transfected with antisense miRNA inhibitors. By constructing more specific and stable forms of miR-106b controlling systems, we further confirmed that overexpression of precursor-miR-106b-5p led to a decrease in KCNQ current density and an increase in firing frequency of hippocampal neurons, while tough decoy miR-106b-5p dramatically increased current density and decreased neuronal excitability. These results unmask a regulatory mechanism of KCNQ2 channel expression in early postnatal development and hint at a role for miR-106b up-regulation in the pathophysiology of epilepsy.
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34
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Aiba I, Noebels JL. Kcnq2/Kv7.2 controls the threshold and bi-hemispheric symmetry of cortical spreading depolarization. Brain 2021; 144:2863-2878. [PMID: 33768249 PMCID: PMC8536937 DOI: 10.1093/brain/awab141] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/22/2021] [Accepted: 03/20/2021] [Indexed: 12/03/2022] Open
Abstract
Spreading depolarization is a slowly propagating wave of massive cellular depolarization associated with acute brain injury and migraine aura. Genetic studies link depolarizing molecular defects in Ca2+ flux, Na+ current in interneurons, and glial Na+-K+ ATPase with spreading depolarization susceptibility, emphasizing the important roles of synaptic activity and extracellular ionic homeostasis in determining spreading depolarization threshold. In contrast, although gene mutations in voltage-gated potassium ion channels that shape intrinsic membrane excitability are frequently associated with epilepsy susceptibility, it is not known whether epileptogenic mutations that regulate membrane repolarization also modify spreading depolarization threshold and propagation. Here we report that the Kcnq2/Kv7.2 potassium channel subunit, frequently mutated in developmental epilepsy, is a spreading depolarization modulatory gene with significant control over the seizure-spreading depolarization transition threshold, bi-hemispheric cortical expression, and diurnal temporal susceptibility. Chronic DC-band cortical EEG recording from behaving conditional Kcnq2 deletion mice (Emx1cre/+::Kcnq2flox/flox) revealed spontaneous cortical seizures and spreading depolarization. In contrast to the related potassium channel deficient model, Kv1.1-KO mice, spontaneous cortical spreading depolarizations in Kcnq2 cKO mice are tightly coupled to the terminal phase of seizures, arise bilaterally, and are observed predominantly during the dark phase. Administration of the non-selective Kv7.2 inhibitor XE991 to Kv1.1-KO mice partly reproduced the Kcnq2 cKO-like spreading depolarization phenotype (tight seizure coupling and bilateral symmetry) in these mice, indicating that Kv7.2 currents can directly and actively modulate spreading depolarization properties. In vitro brain slice studies confirmed that Kcnq2/Kv7.2 depletion or pharmacological inhibition intrinsically lowers the cortical spreading depolarization threshold, whereas pharmacological Kv7.2 activators elevate the threshold to multiple depolarizing and hypometabolic spreading depolarization triggers. Together these results identify Kcnq2/Kv7.2 as a distinctive spreading depolarization regulatory gene, and point to spreading depolarization as a potentially significant pathophysiological component of KCNQ2-linked epileptic encephalopathy syndromes. Our results also implicate KCNQ2/Kv7.2 channel activation as a potential adjunctive therapeutic target to inhibit spreading depolarization incidence.
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Affiliation(s)
- Isamu Aiba
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jeffrey L Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
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35
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Monni L, Kraus L, Dipper-Wawra M, Soares-da-Silva P, Maier N, Schmitz D, Holtkamp M, Fidzinski P. In vitro and in vivo anti-epileptic efficacy of eslicarbazepine acetate in a mouse model of KCNQ2-related self-limited epilepsy. Br J Pharmacol 2021; 179:84-102. [PMID: 34605012 DOI: 10.1111/bph.15689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 08/26/2021] [Accepted: 09/08/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The KCNQ2 gene encodes for the Kv 7.2 subunit of non-inactivating potassium channels. KCNQ2-related diseases range from autosomal dominant neonatal self-limited epilepsy, often caused by KCNQ2 haploinsufficiency, to severe encephalopathies caused by KCNQ2 missense variants. In vivo and in vitro effects of the sodium channel blocker eslicarbazepine acetate (ESL) and eslicarbazepine metabolite (S-Lic) in a mouse model of self-limited neonatal epilepsy as a first attempt to assess the utility of ESL in the KCNQ2 disease spectrum was investigated. EXPERIMENTAL APPROACH Effects of S-Lic on in vitro physiological and pathological hippocampal neuronal activity in slices from mice carrying a heterozygous deletion of Kcnq2 (Kcnq2+/- ) and Kcnq2+/+ mice were investigated. ESL in vivo efficacy was investigated in the 6-Hz psychomotor seizure model in both Kcnq2+/- and Kcnq2+/+ mice. KEY RESULTS S-Lic increased the amplitude and decreased the incidence of physiological sharp wave-ripples in a concentration-dependent manner and slightly decreased gamma oscillations frequency. 4-Aminopyridine-evoked seizure-like events were blocked at high S-Lic concentrations and substantially reduced in incidence at lower concentrations. These results were not different in Kcnq2+/+ and Kcnq2+/- mice, although the EC50 estimation implicated higher efficacy in Kcnq2+/- animals. In vivo, Kcnq2+/- mice had a lower seizure threshold than Kcnq2+/+ mice. In both genotypes, ESL dose-dependently displayed protection against seizures. CONCLUSIONS AND IMPLICATIONS S-Lic slightly modulates hippocampal oscillations and blocks epileptic activity in vitro and in vivo. Our results suggest that the increased excitability in Kcnq2+/- mice is effectively targeted by S-Lic high concentrations, presumably by blocking diverse sodium channel subtypes.
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Affiliation(s)
- Laura Monni
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Clinical Research Centre, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Larissa Kraus
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Life Sciences Institute, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthias Dipper-Wawra
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Patricio Soares-da-Silva
- Division of Research and Development, BIAL - Portela & CA S. A, da Siderurgia Nacional, São Mamede do Coronado, Portugal.,Department of Biomedicine, Unit of Pharmacology and Therapeutics, Faculty of Medicine, University Porto, Porto, Portugal.,MedInUP, Centre for Drug Discovery and Innovative Medicines, University Porto, Porto, Portugal
| | - Nikolaus Maier
- Neuroscience Research Centre, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Centre, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Martin Holtkamp
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Epilepsy-Center Berlin-Brandenburg, Institute for Diagnostics of Epilepsy, Berlin, Germany
| | - Pawel Fidzinski
- Clinical and Experimental Epileptology, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,NeuroCure Clinical Research Centre, Berlin Institute of Health at Charité-Universitätsmedizin Berlin, Berlin, Germany
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36
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Yuan JH, Estacion M, Mis MA, Tanaka BS, Schulman BR, Chen L, Liu S, Dib-Hajj FB, Dib-Hajj SD, Waxman SG. KCNQ variants and pain modulation: a missense variant in Kv7.3 contributes to pain resilience. Brain Commun 2021; 3:fcab212. [PMID: 34557669 PMCID: PMC8454204 DOI: 10.1093/braincomms/fcab212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/13/2021] [Accepted: 07/29/2021] [Indexed: 12/02/2022] Open
Abstract
There is a pressing need for understanding of factors that confer resilience to pain. Gain-of-function mutations in sodium channel Nav1.7 produce hyperexcitability of dorsal root ganglion neurons underlying inherited erythromelalgia, a human genetic model of neuropathic pain. While most individuals with erythromelalgia experience excruciating pain, occasional outliers report more moderate pain. These differences in pain profiles in blood-related erythromelalgia subjects carrying the same pain-causative Nav1.7 mutation and markedly different pain experience provide a unique opportunity to investigate potential genetic factors that contribute to inter-individual variability in pain. We studied a patient with inherited erythromelalgia and a Nav1.7 mutation (c.4345T>G, p. F1449V) with severe pain as is characteristic of most inherited erythromelalgia patients, and her mother who carries the same Nav1.7 mutation with a milder pain phenotype. Detailed six-week daily pain diaries of pain episodes confirmed their distinct pain profiles. Electrophysiological studies on subject-specific induced pluripotent stem cell-derived sensory neurons from each of these patients showed that the excitability of these cells paralleled their pain phenotype. Whole-exome sequencing identified a missense variant (c.2263C>T, p. D755N) in KCNQ3 (Kv7.3) in the pain resilient mother. Voltage-clamp recordings showed that co-expression of Kv7.2-wild type (WT)/Kv7.3-D755N channels produced larger M-currents than that of Kv7.2-WT/Kv7.3-WT. The difference in excitability of the patient-specific induced pluripotent stem cell-derived sensory neurons was mimicked by modulating M-current levels using the dynamic clamp and a model of the mutant Kv7.2-WT/Kv7.3-D755N channels. These results show that a 'pain-in-a-dish' model can be used to explicate genetic contributors to pain, and confirm that KCNQ variants can confer pain resilience via an effect on peripheral sensory neurons.
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Affiliation(s)
- Jun-Hui Yuan
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Mark Estacion
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Malgorzata A Mis
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Brian S Tanaka
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Betsy R Schulman
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Lubin Chen
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Shujun Liu
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Fadia B Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Sulayman D Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06520, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
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37
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Effects of Cooling Temperatures via Thermal K2P Channels on Regeneration of High-Frequency Action Potentials at Nodes of Ranvier of Rat Aβ-Afferent Nerves. eNeuro 2021; 8:ENEURO.0308-21.2021. [PMID: 34462308 PMCID: PMC8445039 DOI: 10.1523/eneuro.0308-21.2021] [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: 07/19/2021] [Revised: 07/28/2021] [Accepted: 08/17/2021] [Indexed: 12/02/2022] Open
Abstract
Temperature-sensitive two-pore domain potassium channels (thermal K2P) are recently shown to cluster at nodes of Ranvier (NRs) and play a key role in action potential (AP) regeneration and conduction on Aβ-afferent nerves. Cooling temperatures affect AP regeneration and conduction on Aβ-afferent nerves but the underlying mechanisms are not completely understood. Here, we have performed patch-clamp recordings directly at the NR in an ex vivo trigeminal nerve preparation. We have characterized the effects of cooling temperatures on intrinsic electrophysiological properties and AP regeneration at the NR on rat Aβ-afferent nerves, and determined whether and how thermal K2P channels may be involved in the effects of cooling temperatures. We show that cooling temperatures from 35°C to 15°C decrease outward leak currents, increase input resistance, depolarize resting membrane potential (RMP), broaden AP width and increase latency of AP threshold at the NR. We further demonstrate that cooling temperatures impair regeneration of high-frequency AP trains at the NR. The effects of cooling temperatures on the intrinsic electrophysiological properties and regeneration of high-frequency AP trains at the NR can be partially reversed by BL-1249 (BL), arachidonic acid (AA), and intra-axonal protons, three thermal K2P activators, indicating the involvement of thermal K2P channels. Moreover, we show that at cooling temperatures there are interplays among thermal K2P channels, RMPs, and voltage-gated Na+ channels, which together limit regeneration of high-frequency AP trains at the NR. Our findings demonstrate a new role of thermal K2P channels in temperature-dependent conduction of high-frequency sensory signals.
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38
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Schwarz JR. Function of K2P channels in the mammalian node of Ranvier. J Physiol 2021; 599:4427-4439. [PMID: 34425634 DOI: 10.1113/jp281723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/09/2021] [Indexed: 11/08/2022] Open
Abstract
In myelinated nerve fibres, action potentials are generated at nodes of Ranvier. These structures are located at interruptions of the myelin sheath, forming narrow gaps with small rings of axolemma freely exposed to the extracellular space. The mammalian node contains a high density of Na+ channels and K+ -selective leakage channels. Voltage-dependent Kv1 channels are only present in the juxta-paranode. Recently, the leakage channels have been identified as K2P channels (TRAAK, TREK-1). K2P channels are K+ -selective 'background' channels, characterized by outward rectification and their ability to be activated, e.g. by temperature, mechanical stretch or arachidonic acid. We are only beginning to elucidate the peculiar functions of nodal K2P channels. I will discuss two functions of the nodal K2P-mediated conductance. First, at body temperature K2P channels have a high open probability, thereby inducing a resting potential of about -85 mV. This negative resting potential reduces steady-state Na+ channel inactivation and ensures a large Na+ inward current upon a depolarizing stimulus. Second, the K2P conductance is involved in nodal action potential repolarization. The identification of nodal K2P channels is exciting since it shows that the nodal K+ conductance is not a fixed value but can be changed: it can be increased or decreased by a broad range of K2P modulators, thereby modulating, for example, the resting potential. The functional importance of nodal K2P channels will be exemplified by describing in more detail the function of the K2P conductance increase by raising the temperature from room temperature to 37°C.
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Affiliation(s)
- Jürgen R Schwarz
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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39
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Bayasgalan T, Stupniki S, Kovács A, Csemer A, Szentesi P, Pocsai K, Dionisio L, Spitzmaul G, Pál B. Alteration of Mesopontine Cholinergic Function by the Lack of KCNQ4 Subunit. Front Cell Neurosci 2021; 15:707789. [PMID: 34381336 PMCID: PMC8352570 DOI: 10.3389/fncel.2021.707789] [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: 05/10/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
The pedunculopontine nucleus (PPN), a structure known as a cholinergic member of the reticular activating system (RAS), is source and target of cholinergic neuromodulation and contributes to the regulation of the sleep–wakefulness cycle. The M-current is a voltage-gated potassium current modulated mainly by cholinergic signaling. KCNQ subunits ensemble into ion channels responsible for the M-current. In the central nervous system, KCNQ4 expression is restricted to certain brainstem structures such as the RAS nuclei. Here, we investigated the presence and functional significance of KCNQ4 in the PPN by behavioral studies and the gene and protein expressions and slice electrophysiology using a mouse model lacking KCNQ4 expression. We found that this mouse has alterations in the adaptation to changes in light–darkness cycles, representing the potential role of KCNQ4 in the regulation of the sleep–wakefulness cycle. As cholinergic neurons from the PPN participate in the regulation of this cycle, we investigated whether the cholinergic PPN might also possess functional KCNQ4 subunits. Although the M-current is an electrophysiological hallmark of cholinergic neurons, only a subpopulation of them had KCNQ4-dependent M-current. Interestingly, the absence of the KCNQ4 subunit altered the expression patterns of the other KCNQ subunits in the PPN. We also determined that, in wild-type animals, the cholinergic inputs of the PPN modulated the M-current, and these in turn can modulate the level of synchronization between neighboring PPN neurons. Taken together, the KCNQ4 subunit is present in a subpopulation of PPN cholinergic neurons, and it may contribute to the regulation of the sleep–wakefulness cycle.
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Affiliation(s)
- T Bayasgalan
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - S Stupniki
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional Del Sur (UNS), Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - A Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - A Csemer
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - P Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - K Pocsai
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - L Dionisio
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional Del Sur (UNS), Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - G Spitzmaul
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional Del Sur (UNS), Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - B Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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40
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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41
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Zybura A, Hudmon A, Cummins TR. Distinctive Properties and Powerful Neuromodulation of Na v1.6 Sodium Channels Regulates Neuronal Excitability. Cells 2021; 10:cells10071595. [PMID: 34202119 PMCID: PMC8307729 DOI: 10.3390/cells10071595] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Navs) are critical determinants of cellular excitability. These ion channels exist as large heteromultimeric structures and their activity is tightly controlled. In neurons, the isoform Nav1.6 is highly enriched at the axon initial segment and nodes, making it critical for the initiation and propagation of neuronal impulses. Changes in Nav1.6 expression and function profoundly impact the input-output properties of neurons in normal and pathological conditions. While mutations in Nav1.6 may cause channel dysfunction, aberrant changes may also be the result of complex modes of regulation, including various protein-protein interactions and post-translational modifications, which can alter membrane excitability and neuronal firing properties. Despite decades of research, the complexities of Nav1.6 modulation in health and disease are still being determined. While some modulatory mechanisms have similar effects on other Nav isoforms, others are isoform-specific. Additionally, considerable progress has been made toward understanding how individual protein interactions and/or modifications affect Nav1.6 function. However, there is still more to be learned about how these different modes of modulation interact. Here, we examine the role of Nav1.6 in neuronal function and provide a thorough review of this channel’s complex regulatory mechanisms and how they may contribute to neuromodulation.
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Affiliation(s)
- Agnes Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA;
| | - Theodore R. Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
- Correspondence:
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42
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Naffaa MM, Al-Ewaidat OA. Ligand modulation of KCNQ-encoded (K V7) potassium channels in the heart and nervous system. Eur J Pharmacol 2021; 906:174278. [PMID: 34174270 DOI: 10.1016/j.ejphar.2021.174278] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/06/2021] [Accepted: 06/18/2021] [Indexed: 10/21/2022]
Abstract
KCNQ-encoded (KV7) potassium channels are diversely distributed in the human tissues, associated with many physiological processes and pathophysiological conditions. These channels are increasingly used as drug targets for treating diseases. More selective and potent molecules on various types of the KV7 channels are desirable for appropriate therapies. The recent knowledge of the structure and function of human KCNQ-encoded channels makes it more feasible to achieve these goals. This review discusses the role and mechanism of action of many molecules in modulating the function of the KCNQ-encoded potassium channels in the heart and nervous system. The effects of these compounds on KV7 channels help to understand their involvement in many diseases, and to search for more selective and potent ligands to be used in the treatment of many disorders such as various types of cardiac arrhythmias, epilepsy, and pain.
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Affiliation(s)
- Moawiah M Naffaa
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA.
| | - Ola A Al-Ewaidat
- Faculty of Medicine, The University of Jordan, Amman, 11942, Jordan
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43
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Dwivedi D, Bhalla US. Physiology and Therapeutic Potential of SK, H, and M Medium AfterHyperPolarization Ion Channels. Front Mol Neurosci 2021; 14:658435. [PMID: 34149352 PMCID: PMC8209339 DOI: 10.3389/fnmol.2021.658435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/13/2021] [Indexed: 12/19/2022] Open
Abstract
SK, HCN, and M channels are medium afterhyperpolarization (mAHP)-mediating ion channels. The three channels co-express in various brain regions, and their collective action strongly influences cellular excitability. However, significant diversity exists in the expression of channel isoforms in distinct brain regions and various subcellular compartments, which contributes to an equally diverse set of specific neuronal functions. The current review emphasizes the collective behavior of the three classes of mAHP channels and discusses how these channels function together although they play specialized roles. We discuss the biophysical properties of these channels, signaling pathways that influence the activity of the three mAHP channels, various chemical modulators that alter channel activity and their therapeutic potential in treating various neurological anomalies. Additionally, we discuss the role of mAHP channels in the pathophysiology of various neurological diseases and how their modulation can alleviate some of the symptoms.
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Affiliation(s)
- Deepanjali Dwivedi
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India.,Department of Neurobiology, Harvard Medical School, Boston, MA, United States.,Stanley Center at the Broad, Cambridge, MA, United States
| | - Upinder S Bhalla
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India
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44
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Springer K, Varghese N, Tzingounis AV. Flexible Stoichiometry: Implications for KCNQ2- and KCNQ3-Associated Neurodevelopmental Disorders. Dev Neurosci 2021; 43:191-200. [PMID: 33794528 PMCID: PMC8440324 DOI: 10.1159/000515495] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/25/2021] [Indexed: 11/19/2022] Open
Abstract
KCNQ2 and KCNQ3 pathogenic channel variants have been associated with a spectrum of developmentally regulated diseases that vary in age of onset, severity, and whether it is transient (i.e., benign familial neonatal seizures) or long-lasting (i.e., developmental and epileptic encephalopathy). KCNQ2 and KCNQ3 channels have also emerged as a target for novel antiepileptic drugs as their activation could reduce epileptic activity. Consequently, a great effort has taken place over the last 2 decades to understand the mechanisms that control the assembly, gating, and modulation of KCNQ2 and KCNQ3 channels. The current view that KCNQ2 and KCNQ3 channels assemble as heteromeric channels (KCNQ2/3) forms the basis of our understanding of KCNQ2 and KCNQ3 channelopathies and drug design. Here, we review the evidence that supports the formation of KCNQ2/3 heteromers in neurons. We also highlight functional and transcriptomic studies that suggest channel composition might not be necessarily fixed in the nervous system, but rather is dynamic and flexible, allowing some neurons to express KCNQ2 and KCNQ3 homomers. We propose that to fully understand KCNQ2 and KCNQ3 channelopathies, we need to adopt a more flexible view of KCNQ2 and KCNQ3 channel stoichiometry, which might differ across development, brain regions, cell types, and disease states.
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Affiliation(s)
- Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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45
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Mazuir E, Fricker D, Sol-Foulon N. Neuron-Oligodendrocyte Communication in Myelination of Cortical GABAergic Cells. Life (Basel) 2021; 11:216. [PMID: 33803153 PMCID: PMC7999565 DOI: 10.3390/life11030216] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 11/17/2022] Open
Abstract
Axonal myelination by oligodendrocytes increases the speed and reliability of action potential propagation, and so plays a pivotal role in cortical information processing. The extent and profile of myelination vary between different cortical layers and groups of neurons. Two subtypes of cortical GABAergic neurons are myelinated: fast-spiking parvalbumin-expressing cells and somatostatin-containing cells. The expression of pre-nodes on the axon of these inhibitory cells before myelination illuminates communication between oligodendrocytes and neurons. We explore the consequences of myelination for action potential propagation, for patterns of neuronal connectivity and for the expression of behavioral plasticity.
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Affiliation(s)
- Elisa Mazuir
- Inserm, CNRS, Paris Brain Institute, ICM, Sorbonne University, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | - Desdemona Fricker
- CNRS UMR 8002, Integrative Neuroscience and Cognition Center, Université de Paris, F-75006 Paris, France
| | - Nathalie Sol-Foulon
- Inserm, CNRS, Paris Brain Institute, ICM, Sorbonne University, Pitié-Salpêtrière Hospital, F-75013 Paris, France
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46
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Kawagashira Y, Koike H, Takahashi M, Ohyama K, Iijima M, Katsuno M, Niwa JI, Doyu M, Sobue G. Aberrant Expression of Nodal and Paranodal Molecules in Neuropathy Associated With IgM Monoclonal Gammopathy With Anti-Myelin-Associated Glycoprotein Antibodies. J Neuropathol Exp Neurol 2021; 79:1303-1312. [PMID: 32856086 DOI: 10.1093/jnen/nlaa085] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/02/2020] [Accepted: 07/09/2020] [Indexed: 11/13/2022] Open
Abstract
To clarify the pathogenesis of anti-myelin-associated glycoprotein (MAG) antibody neuropathy associated with IgM monoclonal gammopathy (anti-MAG neuropathy), sural nerve biopsy specimens from 15 patients were investigated. Sodium channels, potassium channels, contactin-associated protein 1 (Caspr1), contactin 1, and neurofascin were evaluated by immunofluorescence in teased-fiber preparations. Immunoreactivity to the pan-sodium channel in both anti-MAG neuropathy patients and in normal controls was concentrated at the node of Ranvier unless there was demyelination, which was defined as the widening of the node of Ranvier. However, this immunoreactivity became weak or disappeared as demyelination progressed. In contrast, KCNQ2 immunostaining was nearly absent even in the absence of demyelination. The lengths of Caspr1, contactin 1, and pan-neurofascin immunostaining sites at the paranode were significantly increased compared with those of normal controls despite the absence of demyelination. The length of paranodal neurofascin staining correlated with the anti-MAG antibody titer, nerve conduction indices, the frequency of de/remyelination in teased-fiber preparations, and the frequency of widely spaced myelin (p < 0.05, p < 0.05, p < 0.01, and <0.05, respectively). These findings suggest that nodal and paranodal molecular alterations occur in early stages preceding the morphological changes associated with demyelination in anti-MAG neuropathy.
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Affiliation(s)
| | - Haruki Koike
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya
| | - Mie Takahashi
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya
| | - Ken Ohyama
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya
| | - Masahiro Iijima
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya
| | - Jun-Ichi Niwa
- Department of Neurology, Aichi Medical University, Nagakute
| | - Manabu Doyu
- Department of Neurology, Aichi Medical University, Nagakute
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya.,Research Division of Dementia and Neurodegenerative Disease, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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47
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Ronchi S, Buccino AP, Prack G, Kumar SS, Schröter M, Fiscella M, Hierlemann A. Electrophysiological Phenotype Characterization of Human iPSC-Derived Neuronal Cell Lines by Means of High-Density Microelectrode Arrays. Adv Biol (Weinh) 2021; 5:e2000223. [PMID: 33729694 PMCID: PMC7610355 DOI: 10.1002/adbi.202000223] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/30/2020] [Indexed: 12/11/2022]
Abstract
Recent advances in the field of cellular reprogramming have opened a route to studying the fundamental mechanisms underlying common neurological disorders. High-density microelectrode-arrays (HD-MEAs) provide unprecedented means to study neuronal physiology at different scales, ranging from network through single-neuron to subcellular features. In this work, HD-MEAs are used in vitro to characterize and compare human induced-pluripotent-stem-cell-derived dopaminergic and motor neurons, including isogenic neuronal lines modeling Parkinson's disease and amyotrophic lateral sclerosis. Reproducible electrophysiological network, single-cell and subcellular metrics are used for phenotype characterization and drug testing. Metrics, such as burst shape and axonal velocity, enable the distinction of healthy and diseased neurons. The HD-MEA metrics can also be used to detect the effects of dosing the drug retigabine to human motor neurons. Finally, it is shown that the ability to detect drug effects and the observed culture-to-culture variability critically depend on the number of available recording electrodes.
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Affiliation(s)
- Silvia Ronchi
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Alessio Paolo Buccino
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Gustavo Prack
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Sreedhar Saseendran Kumar
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Manuel Schröter
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Michele Fiscella
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
- MaxWell Biosystems AG, Albisriederstrasse 253, Zürich, 8047, Switzerland
| | - Andreas Hierlemann
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
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48
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Simkin D, Marshall KA, Vanoye CG, Desai RR, Bustos BI, Piyevsky BN, Ortega JA, Forrest M, Robertson GL, Penzes P, Laux LC, Lubbe SJ, Millichap JJ, George AL, Kiskinis E. Dyshomeostatic modulation of Ca 2+-activated K + channels in a human neuronal model of KCNQ2 encephalopathy. eLife 2021; 10:64434. [PMID: 33544076 PMCID: PMC7864629 DOI: 10.7554/elife.64434] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/20/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in KCNQ2, which encodes a pore-forming K+ channel subunit responsible for neuronal M-current, cause neonatal epileptic encephalopathy, a complex disorder presenting with severe early-onset seizures and impaired neurodevelopment. The condition is exceptionally difficult to treat, partially because the effects of KCNQ2 mutations on the development and function of human neurons are unknown. Here, we used induced pluripotent stem cells (iPSCs) and gene editing to establish a disease model and measured the functional properties of differentiated excitatory neurons. We find that patient iPSC-derived neurons exhibit faster action potential repolarization, larger post-burst afterhyperpolarization and a functional enhancement of Ca2+-activated K+ channels. These properties, which can be recapitulated by chronic inhibition of M-current in control neurons, facilitate a burst-suppression firing pattern that is reminiscent of the interictal electroencephalography pattern in patients. Our findings suggest that dyshomeostatic mechanisms compound KCNQ2 loss-of-function leading to alterations in the neurodevelopmental trajectory of patient iPSC-derived neurons.
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Affiliation(s)
- Dina Simkin
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Kelly A Marshall
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Carlos G Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Reshma R Desai
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Bernabe I Bustos
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Brandon N Piyevsky
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Juan A Ortega
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Marc Forrest
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Gabriella L Robertson
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Peter Penzes
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Linda C Laux
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Steven J Lubbe
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - John J Millichap
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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49
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Khoubza L, Chatelain FC, Feliciangeli S, Lesage F, Bichet D. Physiological roles of heteromerization: focus on the two-pore domain potassium channels. J Physiol 2021; 599:1041-1055. [PMID: 33347640 DOI: 10.1113/jp279870] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/07/2020] [Indexed: 12/28/2022] Open
Abstract
Potassium channels form the largest family of ion channels with more than 80 members involved in cell excitability and signalling. Most of them exist as homomeric channels, whereas specific conditions are required to obtain heteromeric channels. It is well established that heteromerization of voltage-gated and inward rectifier potassium channels affects their function, increasing the diversity of the native potassium currents. For potassium channels with two pore domains (K2P ), homomerization has long been considered the rule, their polymodal regulation by a wide diversity of physical and chemical stimuli being responsible for the adaptation of the leak potassium currents to cellular needs. This view has recently evolved with the accumulation of evidence of heteromerization between different K2P subunits. Several functional intragroup and intergroup heteromers have recently been identified, which contribute to the functional heterogeneity of this family. K2P heteromerization is involved in the modulation of channel expression and trafficking, promoting functional and signalling diversity. As illustrated in the Abstract Figure, heteromerization of TREK1 and TRAAK provides the cell with more possibilities of regulation. It is becoming increasingly evident that K2P heteromers contribute to important physiological functions including neuronal and cardiac excitability. Since heteromerization also affects the pharmacology of K2P channels, this understanding helps to establish K2P heteromers as new therapeutic targets for physiopathological conditions.
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Affiliation(s)
- Lamyaa Khoubza
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France
| | - Franck C Chatelain
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France
| | - Sylvain Feliciangeli
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France.,Inserm, 101 rue de Tolbiac, 75013, Paris, France
| | - Florian Lesage
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France.,Inserm, 101 rue de Tolbiac, 75013, Paris, France
| | - Delphine Bichet
- Université côte d'Azur, IPMC CNRS UMR7275, Laboratory of Excellence ICST, 660 route des Lucioles 06650 Valbonne, France
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50
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Assembly and Function of the Juxtaparanodal Kv1 Complex in Health and Disease. Life (Basel) 2020; 11:life11010008. [PMID: 33374190 PMCID: PMC7824554 DOI: 10.3390/life11010008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The precise axonal distribution of specific potassium channels is known to secure the shape and frequency of action potentials in myelinated fibers. The low-threshold voltage-gated Kv1 channels located at the axon initial segment have a significant influence on spike initiation and waveform. Their role remains partially understood at the juxtaparanodes where they are trapped under the compact myelin bordering the nodes of Ranvier in physiological conditions. However, the exposure of Kv1 channels in de- or dys-myelinating neuropathy results in alteration of saltatory conduction. Moreover, cell adhesion molecules associated with the Kv1 complex, including Caspr2, Contactin2, and LGI1, are target antigens in autoimmune diseases associated with hyperexcitability such as encephalitis, neuromyotonia, or neuropathic pain. The clustering of Kv1.1/Kv1.2 channels at the axon initial segment and juxtaparanodes is based on interactions with cell adhesion molecules and cytoskeletal linkers. This review will focus on the trafficking and assembly of the axonal Kv1 complex in the peripheral and central nervous system (PNS and CNS), during development, and in health and disease.
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