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Regulatory Effect of General Anesthetics on Activity of Potassium Channels. Neurosci Bull 2018; 34:887-900. [PMID: 29948841 PMCID: PMC6129254 DOI: 10.1007/s12264-018-0239-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/12/2018] [Indexed: 12/19/2022] Open
Abstract
General anesthesia is an unconscious state induced by anesthetics for surgery. The molecular targets and cellular mechanisms of general anesthetics in the mammalian nervous system have been investigated during past decades. In recent years, K+ channels have been identified as important targets of both volatile and intravenous anesthetics. This review covers achievements that have been made both on the regulatory effect of general anesthetics on the activity of K+ channels and their underlying mechanisms. Advances in research on the modulation of K+ channels by general anesthetics are summarized and categorized according to four large K+ channel families based on their amino-acid sequence homology. In addition, research achievements on the roles of K+ channels in general anesthesia in vivo, especially with regard to studies using mice with K+ channel knockout, are particularly emphasized.
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102
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Du X, Gao H, Jaffe D, Zhang H, Gamper N. M-type K + channels in peripheral nociceptive pathways. Br J Pharmacol 2018; 175:2158-2172. [PMID: 28800673 PMCID: PMC5980636 DOI: 10.1111/bph.13978] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/17/2017] [Accepted: 08/03/2017] [Indexed: 12/22/2022] Open
Abstract
Pathological pain is a hyperexcitability disorder. Since the excitability of a neuron is set and controlled by a complement of ion channels it expresses, in order to understand and treat pain, we need to develop a mechanistic insight into the key ion channels controlling excitability within the mammalian pain pathways and how these ion channels are regulated and modulated in various physiological and pathophysiological settings. In this review, we will discuss the emerging data on the expression in pain pathways, functional role and modulation of a family of voltage-gated K+ channels called 'M channels' (KCNQ, Kv 7). M channels are increasingly recognized as important players in controlling pain signalling, especially within the peripheral somatosensory system. We will also discuss the therapeutic potential of M channels as analgesic drug targets. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc/.
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Affiliation(s)
- Xiaona Du
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Haixia Gao
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
| | - David Jaffe
- Department of Biology, UTSA Neurosciences InstituteUniversity of Texas at San AntonioSan AntonioTXUSA
| | - Hailin Zhang
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Nikita Gamper
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
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103
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Ghezzi F, Monni L, Nistri A. Functional up-regulation of the M-current by retigabine contrasts hyperexcitability and excitotoxicity on rat hypoglossal motoneurons. J Physiol 2018; 596:2611-2629. [PMID: 29736957 DOI: 10.1113/jp275906] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/23/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Excessive neuronal excitability characterizes several neuropathological conditions, including neurodegenerative diseases such as amyotrophic lateral sclerosis. Hypoglossal motoneurons (HMs), which control tongue muscles, are extremely vulnerable to this disease and undergo damage and death when exposed to an excessive glutamate extracellular concentration that causes excitotoxicity. Our laboratory devised an in vitro model of excitotoxicity obtained by pharmacological blockade of glutamate transporters. In this paradigm, HMs display hyperexcitability, collective bursting and eventually cell death. The results of the present study show that pharmacological up-regulation of a K+ current (M-current), via application of the anti-convulsant retigabine, prevented all hallmarks of HM excitotoxicity, comprising bursting, generation of reactive oxygen species, expression of toxic markers and cell death. ○Our data may have translational value to develop new treatments against neurological diseases by using positive pharmacological modulators of the M-current. ABSTRACT Neuronal hyperexcitability is a symptom characterizing several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). In the ALS bulbar form, hypoglossal motoneurons (HMs) are an early target for neurodegeneration because of their high vulnerability to metabolic insults. In recent years, our laboratory has developed an in vitro model of a brainstem slice comprising the hypoglossal nucleus in which HM neurodegeneration is achieved by blocking glutamate clearance with dl-threo-β-benzyloxyaspartate (TBOA), thus leading to delayed excitotoxicity. During this process, HMs display a set of hallmarks such as hyperexcitability (and network bursting), reactive oxygen species (ROS) generation and, finally, cell death. The present study aimed to investigate whether blocking early hyperexcitability and bursting with the anti-convulsant drug retigabine was sufficient to achieve neuroprotection against excitotoxicity. Retigabine is a selective positive allosteric modulator of the M-current (IM ), an endogenous mechanism that neurons (comprising HMs) express to dampen excitability. Retigabine (10 μm; co-applied with TBOA) contrasted ROS generation, release of endogenous toxic factors into the HM cytoplasm and excitotoxicity-induced HM death. Electrophysiological experiments showed that retigabine readily contrasted and arrested bursting evoked by TBOA administration. Because neuronal IM subunits (Kv7.2, Kv7.3 and Kv7.5) were expressed in the hypoglossal nucleus and in functionally connected medullary nuclei, we suggest that they were responsible for the strong reduction in network excitability, a potent phenomenon for achieving neuroprotection against TBOA-induced excitotoxicity. The results of the present study may have translational value for testing novel positive pharmacological modulators of the IM under pathological conditions (including neurodegenerative disorders) characterized by excessive neuronal excitability.
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Affiliation(s)
- Filippo Ghezzi
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Laura Monni
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
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104
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Tiwari MN, Mohan S, Biala Y, Yaari Y. Differential contributions of Ca 2+ -activated K + channels and Na + /K + -ATPases to the generation of the slow afterhyperpolarization in CA1 pyramidal cells. Hippocampus 2018; 28:338-357. [PMID: 29431274 PMCID: PMC5947627 DOI: 10.1002/hipo.22836] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/17/2017] [Accepted: 02/05/2018] [Indexed: 12/13/2022]
Abstract
In many types of CNS neurons, repetitive spiking produces a slow afterhyperpolarization (sAHP), providing sustained, intrinsically generated negative feedback to neuronal excitation. Changes in the sAHP have been implicated in learning behaviors, in cognitive decline in aging, and in epileptogenesis. Despite its importance in brain function, the mechanisms generating the sAHP are still controversial. Here we have addressed the roles of M-type K+ current (IM ), Ca2+ -gated K+ currents (ICa(K) 's) and Na+ /K+ -ATPases (NKAs) current to sAHP generation in adult rat CA1 pyramidal cells maintained at near-physiological temperature (35 °C). No evidence for IM contribution to the sAHP was found in these neurons. Both ICa(K) 's and NKA current contributed to sAHP generation, the latter being the predominant generator of the sAHP, particularly when evoked with short trains of spikes. Of the different NKA isoenzymes, α1 -NKA played the key role, endowing the sAHP a steep voltage-dependence. Thus normal and pathological changes in α1 -NKA expression or function may affect cognitive processes by modulating the inhibitory efficacy of the sAHP.
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Affiliation(s)
- Manindra Nath Tiwari
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
| | - Sandesh Mohan
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
| | - Yoav Biala
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
| | - Yoel Yaari
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
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105
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Fosmo AL, Skraastad ØB. The Kv7 Channel and Cardiovascular Risk Factors. Front Cardiovasc Med 2017; 4:75. [PMID: 29259974 PMCID: PMC5723334 DOI: 10.3389/fcvm.2017.00075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/21/2017] [Indexed: 12/30/2022] Open
Abstract
Potassium channels play a pivotal role in the regulation of excitability in cells such as neurons, cardiac myocytes, and vascular smooth muscle cells. The KCNQ (Kv7) family of voltage-activated K+ channels hyperpolarizes the cell and stabilizes the membrane potential. Here, we outline how Kv7 channel activity may contribute to the development of the cardiovascular risk factors such as hypertension, diabetes, and obesity. Questions and hypotheses regarding previous and future research have been raised. Alterations in the Kv7 channel may contribute to the development of cardiovascular disease (CVD). Pharmacological modification of Kv7 channels may represent a possible treatment for CVD in the future.
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Affiliation(s)
- Andreas L Fosmo
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Øyvind B Skraastad
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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106
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Lehman A, Thouta S, Mancini GMS, Naidu S, van Slegtenhorst M, McWalter K, Person R, Mwenifumbo J, Salvarinova R, Guella I, McKenzie MB, Datta A, Connolly MB, Kalkhoran SM, Poburko D, Friedman JM, Farrer MJ, Demos M, Desai S, Claydon T. Loss-of-Function and Gain-of-Function Mutations in KCNQ5 Cause Intellectual Disability or Epileptic Encephalopathy. Am J Hum Genet 2017; 101:65-74. [PMID: 28669405 PMCID: PMC5501867 DOI: 10.1016/j.ajhg.2017.05.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 05/24/2017] [Indexed: 01/31/2023] Open
Abstract
KCNQ5 is a highly conserved gene encoding an important channel for neuronal function; it is widely expressed in the brain and generates M-type current. Exome sequencing identified de novo heterozygous missense mutations in four probands with intellectual disability, abnormal neurological findings, and treatment-resistant epilepsy (in two of four). Comprehensive analysis of this potassium channel for the four variants expressed in frog oocytes revealed shifts in the voltage dependence of activation, including altered activation and deactivation kinetics. Specifically, both loss-of-function and gain-of-function KCNQ5 mutations, associated with increased excitability and decreased repolarization reserve, lead to pathophysiology.
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Affiliation(s)
- Anna Lehman
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 3N1, Canada.
| | - Samrat Thouta
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus University Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Sakkubai Naidu
- Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, MD 21211, USA
| | - Marjon van Slegtenhorst
- Department of Clinical Genetics, Erasmus University Medical Center, 3000 CA Rotterdam, the Netherlands
| | | | | | - Jill Mwenifumbo
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 3N1, Canada
| | - Ramona Salvarinova
- Division of Biochemical Diseases, Department of Pediatrics, University of British Columbia, Vancouver, BC V6H 3N1, Canada
| | - Ilaria Guella
- Centre for Applied Neurogenetics, University of British Columbia, Vancouver BC, V6T 1Z3, Canada
| | - Marna B McKenzie
- Centre for Applied Neurogenetics, University of British Columbia, Vancouver BC, V6T 1Z3, Canada
| | - Anita Datta
- Division of Pediatric Neurology, Department of Pediatrics, University of British Columbia, Vancouver BC, V6H 3N1, Canada
| | - Mary B Connolly
- Division of Pediatric Neurology, Department of Pediatrics, University of British Columbia, Vancouver BC, V6H 3N1, Canada
| | - Somayeh Mojard Kalkhoran
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Damon Poburko
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 3N1, Canada
| | - Matthew J Farrer
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 3N1, Canada; Centre for Applied Neurogenetics, University of British Columbia, Vancouver BC, V6T 1Z3, Canada
| | - Michelle Demos
- Division of Pediatric Neurology, Department of Pediatrics, University of British Columbia, Vancouver BC, V6H 3N1, Canada
| | - Sonal Desai
- Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, MD 21211, USA
| | - Thomas Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
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107
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Pablo JL, Pitt GS. Divide, multitask, and conquer: Coordination in channel regulation. Channels (Austin) 2017; 11:268-270. [PMID: 28282251 DOI: 10.1080/19336950.2017.1292814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Juan Lorenzo Pablo
- a Department of Cardiology, Howard Hughes Medical Institute , Boston Children's Hospital , Boston , MA , USA.,b Department of Neurobiology , Harvard Medical School , Boston , MA , USA
| | - Geoffrey S Pitt
- c Cardiovascular Research Institute , Weill Cornell Medicine , New York , NY , USA
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108
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Greene DL, Kang S, Hoshi N. XE991 and Linopirdine Are State-Dependent Inhibitors for Kv7/KCNQ Channels that Favor Activated Single Subunits. J Pharmacol Exp Ther 2017; 362:177-185. [PMID: 28483800 DOI: 10.1124/jpet.117.241679] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/05/2017] [Indexed: 01/13/2023] Open
Abstract
M-channel inhibitors, especially XE991, are being used increasingly in animal experiments; however, insufficient characterization of XE991 at times confounds the interpretation of results when using this compound. Here, we demonstrate that XE991 and linopirdine are state-dependent inhibitors that favor the activated-subunit of neuronal Kv7/KCNQ channels. We performed patch-clamp experiments on homomeric Kv7.2 or heteromeric Kv7.2/3 channels expressed in Chinese hamster ovary cells to characterize XE991 and linopirdine. Neither inhibitor was efficacious around the resting membrane potential of cells in physiologic conditions. Inhibition of Kv7.2 and Kv7.2/3 channels by XE991 was closely related with channel activation. When the voltage dependence of activation was left-shifted by retigabine or right-shifted by the mutation, Kv7.2(R214D), the shift in half-activation voltage proportionally coincided with the shift in the half-effective potential for XE991 inhibition. Inhibition kinetics during XE991 wash-in was facilitated at depolarized potentials. Ten-minute washout of XE991 resulted in ∼30% current recovery, most of which was attributed to surface transport of Kv7.2 channels. Linopirdine also exhibited similar inhibition characteristics, with the exception of near- complete current recovery after washout at depolarized potentials. Inhibition kinetics of both XE991 and linopirdine was not as sensitive to changes in voltage as would be predicted by open- channel inhibition. Instead, they were well explained by binding to a single activated subunit. The characteristics of XE991 and linopirdine should be taken into account when these M-channel inhibitors are used in experiments.
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Affiliation(s)
- Derek L Greene
- Department of Pharmacology (D.L.G., S.K., N.H.), Department of Physiology and Biophysics (N.H.), University of California Irvine, Irvine, California
| | - Seungwoo Kang
- Department of Pharmacology (D.L.G., S.K., N.H.), Department of Physiology and Biophysics (N.H.), University of California Irvine, Irvine, California
| | - Naoto Hoshi
- Department of Pharmacology (D.L.G., S.K., N.H.), Department of Physiology and Biophysics (N.H.), University of California Irvine, Irvine, California
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109
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Gomis-Perez C, Soldovieri MV, Malo C, Ambrosino P, Taglialatela M, Areso P, Villarroel A. Differential Regulation of PI(4,5)P 2 Sensitivity of Kv7.2 and Kv7.3 Channels by Calmodulin. Front Mol Neurosci 2017; 10:117. [PMID: 28507506 PMCID: PMC5410570 DOI: 10.3389/fnmol.2017.00117] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/10/2017] [Indexed: 11/19/2022] Open
Abstract
HIGHLIGHTS- Calmodulin-dependent Kv7.2 current density without the need of binding calcium. - Kv7.2 current density increase is accompanied with resistance to PI(4,5)P2 depletion. - Kv7.3 current density is insensitive to calmodulin elevation. - Kv7.3 is more sensitive to PI(4,5)P2 depletion in the presence of calmodulin. - Apo-calmodulin influences PI(4,5)P2 dependence in a subunit specific manner.
The identification and understanding of critical factors regulating M-current functional density, whose main components are Kv7.2 and Kv7.3 subunits, has profound pathophysiological impact given the important role of the M-current in neuronal excitability control. We report the increase in current density of Kv7.2 channels by calmodulin (CaM) and by a mutant CaM unable to bind Ca2+ (CaM1234) revealing that this potentiation is calcium independent. Furthermore, after co-expressing a CaM binding protein (CaM sponge) to reduce CaM cellular availability, Kv7.2 current density was reduced. Current inhibition after transient depletion of the essential Kv7 co-factor phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) by activating Danio rerio voltage sensitive phosphatase (DrVSP) was blunted by co-expressing CaM1234 or the CaM sponge. In addition, CaM-dependent potentiation was occluded by tonic elevation of PI(4,5)P2 levels by PI(4)P5-kinase (PIP5K) expression. In contrast to the effect on homomeric Kv7.2 channels, CaM1234 failed to potentiate heteromeric Kv7.2/3 or homomeric Kv7.3 channels. Sensitivity to PI(4,5)P2 depletion of Kv7.2/3 channels was increased after expression of CaM1234 or the CaM sponge, while that of homomeric Kv7.3 was unaltered. Altogether, the data reveal that apo-CaM influences PI(4,5)P2 dependence of Kv7.2, Kv7.2/3, and of Kv7.3 channels in a subunit specific manner.
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Affiliation(s)
- Carolina Gomis-Perez
- Biofisika Institutua, Consejo Superior de Investigaciones Científicas, CSIC, UPV/EHULeioa, Spain
| | - Maria V Soldovieri
- Department of Medicine and Health Science, University of MoliseCampobasso, Italy
| | - Covadonga Malo
- Biofisika Institutua, Consejo Superior de Investigaciones Científicas, CSIC, UPV/EHULeioa, Spain
| | - Paolo Ambrosino
- Department of Medicine and Health Science, University of MoliseCampobasso, Italy
| | - Maurizio Taglialatela
- Department of Medicine and Health Science, University of MoliseCampobasso, Italy.,Department of Neuroscience, University of Naples "Federico II,"Naples, Italy
| | - Pilar Areso
- Department Farmacología, UPV/EHU, Universidad del País VascoLeioa, Spain
| | - Alvaro Villarroel
- Biofisika Institutua, Consejo Superior de Investigaciones Científicas, CSIC, UPV/EHULeioa, Spain
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110
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Ultrastructural anatomy of nodes of Ranvier in the peripheral nervous system as revealed by STED microscopy. Proc Natl Acad Sci U S A 2016; 114:E191-E199. [PMID: 28003466 DOI: 10.1073/pnas.1619553114] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We used stimulated emission depletion (STED) superresolution microscopy to analyze the nanoscale organization of 12 glial and axonal proteins at the nodes of Ranvier of teased sciatic nerve fibers. Cytoskeletal proteins of the axon (betaIV spectrin, ankyrin G) exhibit a high degree of one-dimensional longitudinal order at nodal gaps. In contrast, axonal and glial nodal adhesion molecules [neurofascin-186, neuron glial-related cell adhesion molecule (NrCAM)] can arrange in a more complex, 2D hexagonal-like lattice but still feature a ∼190-nm periodicity. Such a lattice-like organization is also found for glial actin. Sodium and potassium channels exhibit a one-dimensional periodicity, with the Nav channels appearing to have a lower degree of organization. At paranodes, both axonal proteins (betaII spectrin, Caspr) and glial proteins (neurofascin-155, ankyrin B) form periodic quasi-one-dimensional arrangements, with a high degree of interdependence between the position of the axonal and the glial proteins. The results indicate the presence of mechanisms that finely align the cytoskeleton of the axon with the one of the Schwann cells, both at paranodal junctions (with myelin loops) and at nodal gaps (with microvilli). Taken together, our observations reveal the importance of the lateral organization of proteins at the nodes of Ranvier and pave the way for deeper investigations of the molecular ultrastructural mechanisms involved in action potential propagation, the formation of the nodes, axon-glia interactions, and demyelination diseases.
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