1
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Joubert B. The neurobiology and immunology of CASPR2-associated neurological disorders. Rev Neurol (Paris) 2024:S0035-3787(24)00597-6. [PMID: 39341757 DOI: 10.1016/j.neurol.2024.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2024] [Accepted: 09/09/2024] [Indexed: 10/01/2024]
Abstract
CASPR2-associated neurological disorders encompass a wide clinical spectrum broadly divided into overlapping three autoimmune syndromes: CASPR2 limbic encephalitis, Morvan syndrome, and Isaacs syndrome. CASPR2 is a neuronal protein expressed at different sites in the central and peripheral nervous system and has a variety of roles and functions regarding neuronal excitability, synaptic plasticity, and homeostasis of inhibitory networks, most of which are only partially understood. CASPR2 antibodies have various pathogenic effects including internalization of CASPR2, disruption of protein-protein interactions, and, possibly, complement activation. Their pathogenic effect is well demonstrated in the limbic encephalitis phenotype, but the role of pathogenic antibodies in the development of other clinical manifestations is less clear. CASPR2 limbic encephalitis also differ from the other CASPR2-associated disorders in regard to HLA allele and paraneoplastic associations, suggesting it has immunological mechanisms distinct from the other clinical forms. Future studies are needed to better understand how the immunological alterations lead to the different phenotypes associated with CASPR2 antibodies.
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Affiliation(s)
- B Joubert
- Service de neurologie clinique et fonctionnelle, groupe hospitalier Sud, hospices civils de Lyon, Lyon, France; Centre de référence pour les encéphalites auto-immunes et les syndromes neurologiques paranéoplasiques, hospices civils de Lyon, Lyon, France.
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2
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Liu SX, Villacis Calderon DG, Maxim ZL, Beeson MM, Rao R, Tran PV. Neonatal Hypoxia-Ischemia alters Brain-Derived Contactin-2-Positive Extracellular Vesicles in the Mouse Plasma. Neuroscience 2024; 545:141-147. [PMID: 38513760 DOI: 10.1016/j.neuroscience.2024.03.014] [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: 06/29/2023] [Revised: 03/06/2024] [Accepted: 03/16/2024] [Indexed: 03/23/2024]
Abstract
Neonatal encephalopathy (NE) impairs white matter development and results in long-term neurodevelopmental deficits. Leveraging prior findings of altered neuronal proteins carried by brain-derived extracellular vesicles (EVs) that are marked by a neural-specific cell surface glycoprotein Contactin-2 (CNTN2) in NE infants, the present study aimed to determine the correlation between brain and circulating CNTN2+-EVs and whether NE alters circulating CNTN2+-EV levels in mice. Brain tissue and plasma were collected from postnatal day (P)7, 10, 11, 15 mice to determine the baseline CNTN2 correlation between these two compartments (n = 4-7/time point/sex). NE was induced in P10 pups. Brain and plasma samples were collected at 1, 3, 6, 24, and 120 h (n = 4-8/time point/sex). CNTN2 from brain tissue and plasma EVs were quantified using ELISA. ANOVA and linear regression analyses were used to evaluate changes and correlations between brain and plasma CNTN2+-EVs. In baseline experiments, CNTN2 in brain tissue and plasma EVs peaked at P10 with no sex-difference. Brain and plasma CNTN2+-EV showed a positive correlation across early postnatal ages. NE pups showed an elevated CNTN2 in brain tissue and EVs at 1 h and only in brain tissue at 24 h. NE also abolished the positive plasma-brain correlation. The findings establish a link for central CNTN2 and its release into circulation during early postnatal life. The immediate elevation and release of CNTN2 following NE highlight a potential molecular response shortly after a brain injurious event. Our findings further support the utility of circulating brain-derived EVs as a possible bioindicator of NE.
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Affiliation(s)
- Shirelle X Liu
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | | | - Zia L Maxim
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Montana M Beeson
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Raghavendra Rao
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Phu V Tran
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
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3
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Chataigner LMP, Thärichen L, Beugelink JW, Granneman JCM, Mokiem NJ, Snijder J, Förster F, Janssen BJC. Contactin 2 homophilic adhesion structure and conformational plasticity. Structure 2024; 32:60-73.e5. [PMID: 37992710 DOI: 10.1016/j.str.2023.10.012] [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: 06/21/2022] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 11/24/2023]
Abstract
The cell-surface attached glycoprotein contactin 2 is ubiquitously expressed in the nervous system and mediates homotypic cell-cell interactions to organize cell guidance, differentiation, and adhesion. Contactin 2 consists of six Ig and four fibronectin type III domains (FnIII) of which the first four Ig domains form a horseshoe structure important for homodimerization and oligomerization. Here we report the crystal structure of the six-domain contactin 2Ig1-6 and show that the Ig5-Ig6 combination is oriented away from the horseshoe with flexion in interdomain connections. Two distinct dimer states, through Ig1-Ig2 and Ig3-Ig6 interactions, together allow formation of larger oligomers. Combined size exclusion chromatography with multiangle light scattering (SEC-MALS), small-angle X-ray scattering (SAXS) and native MS analysis indicates contactin 2Ig1-6 oligomerizes in a glycan dependent manner. SAXS and negative-stain electron microscopy reveals inherent plasticity of the contactin 2 full-ectodomain. The combination of intermolecular binding sites and ectodomain plasticity explains how contactin 2 can function as a homotypic adhesion molecule in diverse intercellular environments.
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Affiliation(s)
- Lucas M P Chataigner
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Lena Thärichen
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - J Wouter Beugelink
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Joke C M Granneman
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Nadia J Mokiem
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Joost Snijder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Bert J C Janssen
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands.
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4
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Kagiava A, Karaiskos C, Lapathitis G, Heslegrave A, Sargiannidou I, Zetterberg H, Bosch A, Kleopa KA. Gene replacement therapy in two Golgi-retained CMT1X mutants before and after the onset of demyelinating neuropathy. Mol Ther Methods Clin Dev 2023; 30:377-393. [PMID: 37645436 PMCID: PMC10460951 DOI: 10.1016/j.omtm.2023.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023]
Abstract
X-linked Charcot-Marie-Tooth disease type 1 (CMT1X) is a demyelinating neuropathy resulting from loss-of-function mutations affecting the GJB1/connexin 32 (Cx32) gene. We previously showed functional and morphological improvement in Gjb1-null mice following AAV9-mediated delivery of human Cx32 driven by the myelin protein zero (Mpz) promoter in Schwann cells. However, CMT1X mutants may interfere with virally delivered wild-type (WT) Cx32. To confirm the efficacy of this vector also in the presence of CMT1X mutants, we delivered AAV9-Mpz-GJB1 by lumbar intrathecal injection in R75W/Gjb1-null and N175D/Gjb1-null transgenic lines expressing Golgi-retained mutations, before and after the onset of the neuropathy. Widespread expression of virally delivered Cx32 was demonstrated in both genotypes. Re-establishment of WT Cx32 function resulted in improved muscle strength and increased sciatic nerve motor conduction velocities in all treated groups from both mutant lines when treated before as well as after the onset of the neuropathy. Furthermore, morphological analysis showed improvement of myelination and reduction of inflammation in lumbar motor roots and peripheral nerves. In conclusion, this study provides proof of principle for a clinically translatable gene therapy approach to treat CMT1X before and after the onset of the neuropathy, even in the presence of endogenously expressed Golgi-retained Cx32 mutants.
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Affiliation(s)
- Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Christos Karaiskos
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - George Lapathitis
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Amanda Heslegrave
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
| | - Henrik Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute at UCL, London WC1E 6BT, UK
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, 40530 Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 40530 Mölndal, Sweden
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
- Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Assumpció Bosch
- Department of Biochemistry & Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, 08193 Bellatera, Spain
- Unitat Mixta UAB-VHIR, Vall d'Hebron Institut de Recerca (VHIR), 08035 Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, 028029 Madrid, Spain
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
- Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 2371 Nicosia, Cyprus
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5
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Dolma S, Joshi A. The Node of Ranvier as an Interface for Axo-Glial Interactions: Perturbation of Axo-Glial Interactions in Various Neurological Disorders. J Neuroimmune Pharmacol 2023; 18:215-234. [PMID: 37285016 DOI: 10.1007/s11481-023-10072-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 05/19/2023] [Indexed: 06/08/2023]
Abstract
The action potential conduction along the axon is highly dependent on the healthy interactions between the axon and myelin-producing glial cells. Myelin, which facilitates action potential, is the protective insulation around the axon formed by Schwann cells and oligodendrocytes in the peripheral (PNS) and central nervous system (CNS), respectively. Myelin is a continuous structure with intermittent gaps called nodes of Ranvier, which are the sites enriched with ion channels, transmembrane, scaffolding, and cytoskeletal proteins. Decades-long extensive research has identified a comprehensive proteome with strictly regularized localization at the node of Ranvier. Concurrently, axon-glia interactions at the node of Ranvier have gathered significant attention as the pathophysiological targets for various neurodegenerative disorders. Numerous studies have shown the alterations in the axon-glia interactions culminating in neurological diseases. In this review, we have provided an update on the molecular composition of the node of Ranvier. Further, we have discussed in detail the consequences of disruption of axon-glia interactions during the pathogenesis of various CNS and PNS disorders.
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Affiliation(s)
- Sonam Dolma
- Department of Pharmacy, Birla Institute of Technology and Sciences- Pilani, Hyderabad campus, Telangana state, India
| | - Abhijeet Joshi
- Department of Pharmacy, Birla Institute of Technology and Sciences- Pilani, Hyderabad campus, Telangana state, India.
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6
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Gövert F, Abrante L, Becktepe J, Balint B, Ganos C, Hofstadt-van Oy U, Krogias C, Varley J, Irani SR, Paneva S, Titulaer MJ, de Vries JM, Boon AJW, Schreurs MWJ, Joubert B, Honnorat J, Vogrig A, Ariño H, Sabater L, Dalmau J, Scotton S, Jacob S, Melzer N, Bien CG, Geis C, Lewerenz J, Prüss H, Wandinger KP, Deuschl G, Leypoldt F. Distinct movement disorders in contactin-associated-protein-like-2 antibody-associated autoimmune encephalitis. Brain 2023; 146:657-667. [PMID: 35875984 DOI: 10.1093/brain/awac276] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 06/02/2022] [Accepted: 06/22/2022] [Indexed: 11/14/2022] Open
Abstract
Autoimmune encephalitis can be classified into antibody-defined subtypes, which can manifest with immunotherapy-responsive movement disorders sometimes mimicking non-inflammatory aetiologies. In the elderly, anti-LGI1 and contactin associated protein like 2 (CASPR2) antibody-associated diseases compose a relevant fraction of autoimmune encephalitis. Patients with LGI1 autoantibodies are known to present with limbic encephalitis and additionally faciobrachial dystonic seizures may occur. However, the clinical spectrum of CASPR2 autoantibody-associated disorders is more diverse including limbic encephalitis, Morvan's syndrome, peripheral nerve hyperexcitability syndrome, ataxia, pain and sleep disorders. Reports on unusual, sometimes isolated and immunotherapy-responsive movement disorders in CASPR2 autoantibody-associated syndromes have caused substantial concern regarding necessity of autoantibody testing in patients with movement disorders. Therefore, we aimed to systematically assess their prevalence and manifestation in patients with CASPR2 autoimmunity. This international, retrospective cohort study included patients with CASPR2 autoimmunity from participating expert centres in Europe. Patients with ataxia and/or movement disorders were analysed in detail using questionnaires and video recordings. We recruited a comparator group with anti-LGI1 encephalitis from the GENERATE network. Characteristics were compared according to serostatus. We identified 164 patients with CASPR2 autoantibodies. Of these, 149 (90.8%) had only CASPR2 and 15 (9.1%) both CASPR2 and LGI1 autoantibodies. Compared to 105 patients with LGI1 encephalitis, patients with CASPR2 autoantibodies more often had movement disorders and/or ataxia (35.6 versus 3.8%; P < 0.001). This was evident in all subgroups: ataxia 22.6 versus 0.0%, myoclonus 14.6 versus 0.0%, tremor 11.0 versus 1.9%, or combinations thereof 9.8 versus 0.0% (all P < 0.001). The small group of patients double-positive for LGI1/CASPR2 autoantibodies (15/164) significantly more frequently had myoclonus, tremor, 'mixed movement disorders', Morvan's syndrome and underlying tumours. We observed distinct movement disorders in CASPR2 autoimmunity (14.6%): episodic ataxia (6.7%), paroxysmal orthostatic segmental myoclonus of the legs (3.7%) and continuous segmental spinal myoclonus (4.3%). These occurred together with further associated symptoms or signs suggestive of CASPR2 autoimmunity. However, 2/164 patients (1.2%) had isolated segmental spinal myoclonus. Movement disorders and ataxia are highly prevalent in CASPR2 autoimmunity. Paroxysmal orthostatic segmental myoclonus of the legs is a novel albeit rare manifestation. Further distinct movement disorders include isolated and combined segmental spinal myoclonus and autoimmune episodic ataxia.
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Affiliation(s)
- Felix Gövert
- Department of Neurology, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany
| | - Ligia Abrante
- Neuroimmunology, Institute of Clinical Chemistry, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany
| | - Jos Becktepe
- Department of Neurology, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany
| | - Bettina Balint
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Department of Neurology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Christos Ganos
- Department of Neurology, Charité University Medicine Berlin, 10117 Berlin, Germany
| | | | - Christos Krogias
- Department of Neurology, St Josef Hospital, Ruhr University Bochum, 44791 Bochum, Germany
| | - James Varley
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Sarosh R Irani
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Sofija Paneva
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Maarten J Titulaer
- Department of Neurology, Erasmus MC University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Juna M de Vries
- Department of Neurology, Erasmus MC University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Agnita J W Boon
- Department of Neurology, Erasmus MC University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Marco W J Schreurs
- Department of Neurology, Erasmus MC University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Bastien Joubert
- Centre National de Référence pour les Syndromes Neurologiques Paranéoplasiques, Hospices Civils de Lyon, Hôpital Neurologique, 69677 Bron, France.,Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon-Université Claude Bernard Lyon 1, Lyon, France
| | - Jerome Honnorat
- Centre National de Référence pour les Syndromes Neurologiques Paranéoplasiques, Hospices Civils de Lyon, Hôpital Neurologique, 69677 Bron, France.,Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon-Université Claude Bernard Lyon 1, Lyon, France
| | - Alberto Vogrig
- Centre National de Référence pour les Syndromes Neurologiques Paranéoplasiques, Hospices Civils de Lyon, Hôpital Neurologique, 69677 Bron, France.,Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon-Université Claude Bernard Lyon 1, Lyon, France
| | - Helena Ariño
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS); Service of Neurology, Hospital Clínic, University of Barcelona, 08036 Barcelona, Spain
| | - Lidia Sabater
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS); Service of Neurology, Hospital Clínic, University of Barcelona, 08036 Barcelona, Spain
| | - Josep Dalmau
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS); Service of Neurology, Hospital Clínic, University of Barcelona, 08036 Barcelona, Spain.,Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA.,Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
| | - Sangeeta Scotton
- Department of Neurology, University Hospitals Birmingham, Birmingham B15 2TH, UK
| | - Saiju Jacob
- Department of Neurology, University Hospitals Birmingham, Birmingham B15 2TH, UK
| | - Nico Melzer
- Department of Neurology with Institute of Translational Neurology, University of Münster, 48149 Münster, Germany.,Department of Neurology, Medical Faculty, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Christian G Bien
- Department of Epileptology (Krankenhaus Mara), Bielefeld University, Medical School, Campus Bielefeld-Bethel, 33617 Bielefeld, Germany
| | - Christian Geis
- Department of Neurology, University of Jena, 07747 Jena, Germany
| | - Jan Lewerenz
- Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Harald Prüss
- German Center for Neurodegenerative Diseases (DZNE) Berlin and Department of Neurology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Klaus-Peter Wandinger
- Neuroimmunology, Institute of Clinical Chemistry, University Medical Center Schleswig-Holstein, 23538 Lübeck, Germany.,Department of Neurology, University of Luebeck and University Medical Center Schleswig-Holstein, 23538 Lübeck, Germany
| | - Günther Deuschl
- Department of Neurology, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany
| | - Frank Leypoldt
- Department of Neurology, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany.,Neuroimmunology, Institute of Clinical Chemistry, Christian-Albrecht University of Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany
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7
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Harder A, Nagarajan B, Odermatt B, Kubitscheck U. Automatic detector synchronization for long-term imaging using confocal light-sheet microscopy. Microsc Res Tech 2023; 86:125-136. [PMID: 36054690 DOI: 10.1002/jemt.24223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 06/08/2022] [Accepted: 07/28/2022] [Indexed: 01/21/2023]
Abstract
Light sheet fluorescence microscopy (LSFM) is an important tool in developmental biology. In this microscopy technique confocal line detection is often used to improve image contrast. To this end, the image of the illuminating scanned focused laser beam must be mapped onto a line detector. This is not trivial for long-term observations, since the spatial position of the laser beam and therefore its image on the detector may drift. The problem is aggravated in two-photon excitation LSFM, since pulsed laser light sources exhibit a lower laser beam pointing stability than continuous wave lasers. Here, we present a procedure for automatic synchronization between the excitation laser and detector, which does not require any additional hardware components and can therefore easily be integrated into existing systems. Since the recorded images are affected by noise, a specific, noise-tolerant focus metric was developed for calculating the relative displacement, which also allows for autofocusing in the detection direction. Furthermore, we developed an image analysis approach to determine a possible tilt of the excitation laser, which is executed in parallel to the autofocusing and enables the measurement of three solid angles. This allows to automatically correct for the tilting during a measurement. We demonstrated our approach by the observation of the migration of oligodendrocyte precursor cells in two-day-old fluorescent Tg(olig2:eGFP) reporter zebrafish larvae over a time span of more than 20 hours.
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Affiliation(s)
- Alexander Harder
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | | | - Benjamin Odermatt
- Institute of Anatomy, University Clinics, University of Bonn, Bonn, Germany
| | - Ulrich Kubitscheck
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
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8
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Pechlivanidou M, Kousiappa I, Angeli S, Sargiannidou I, Koupparis AM, Papacostas SS, Kleopa KA. Glial Gap Junction Pathology in the Spinal Cord of the 5xFAD Mouse Model of Early-Onset Alzheimer's Disease. Int J Mol Sci 2022; 23:15597. [PMID: 36555237 PMCID: PMC9779687 DOI: 10.3390/ijms232415597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
Gap junctions (GJs) are specialized transmembrane channels assembled by two hemi-channels of six connexin (Cx) proteins that facilitate neuroglial crosstalk in the central nervous system (CNS). Previous studies confirmed the crucial role of glial GJs in neurodegenerative disorders with dementia or motor dysfunction including Alzheimer's disease (AD). The aim of this study was to examine the alterations in astrocyte and related oligodendrocyte GJs in association with Aβ plaques in the spinal cord of the 5xFAD mouse model of AD. Our analysis revealed abundant Aβ plaque deposition, activated microglia, and astrogliosis in 12-month-old (12M) 5xFAD mice, with significant impairment of motor performance starting from 3-months (3M) of age. Additionally, 12M 5xFAD mice displayed increased immunoreactivity of astroglial Cx43 and Cx30 surrounding Aβ plaques and higher protein levels, indicating upregulated astrocyte-to-astrocyte GJ connectivity. In addition, they demonstrated increased numbers of mature CC1-positive and precursor oligodendrocytes (OPCs) with higher immunoreactivity of Cx47-positive GJs in individual cells. Moreover, total Cx47 protein levels were significantly elevated in 12M 5xFAD, reflecting increased oligodendrocyte-to-oligodendrocyte Cx47-Cx47 GJ connectivity. In contrast, we observed a marked reduction in Cx32 protein levels in 12M 5xFAD spinal cords compared with controls, while qRT-PCR analysis revealed a significant upregulation in Cx32 mRNA levels. Finally, myelin deficits were found focally in the areas occupied by Aβ plaques, whereas axons themselves remained preserved. Overall, our data provide novel insights into the altered glial GJ expression in the spinal cord of the 5xFAD model of AD and the implicated role of GJ pathology in neurodegeneration. Further investigation to understand the functional consequences of these extensive alterations in oligodendrocyte-astrocyte (O/A) GJ connectivity is warranted.
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Affiliation(s)
- Maria Pechlivanidou
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Ioanna Kousiappa
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Stella Angeli
- Medical School, University of Nicosia, Nicosia 2414, Cyprus
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Andreas M. Koupparis
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Epilepsy Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Dementia and Cognitive Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Savvas S. Papacostas
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Medical School, University of Nicosia, Nicosia 2414, Cyprus
- Epilepsy Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Dementia and Cognitive Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Center for Multiple Sclerosis and Related Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
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9
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Ktena N, Kaplanis SI, Kolotuev I, Georgilis A, Kallergi E, Stavroulaki V, Nikoletopoulou V, Savvaki M, Karagogeos D. Autophagic degradation of CNS myelin maintains axon integrity. Cell Stress 2022; 6:93-107. [PMID: 36478958 PMCID: PMC9707329 DOI: 10.15698/cst2022.12.274] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 11/01/2022] [Accepted: 11/09/2022] [Indexed: 09/05/2023] Open
Abstract
(Macro)autophagy is a major lysosome-dependent degradation mechanism which engulfs, removes and recycles unwanted cytoplasmic material, including damaged organelles and toxic protein aggregates. Although a few studies implicate autophagy in CNS demyelinating pathologies, its role, particularly in mature oligodendrocytes and CNS myelin, remains poorly studied. Here, using both pharmacological and genetic inhibition of the autophagic machinery, we provide evidence that autophagy is an essential mechanism for oligodendrocyte maturation in vitro. Our study reveals that two core myelin proteins, namely proteolipid protein (PLP) and myelin basic protein (MBP) are incorporated into autophagosomes in oligodendrocytes, resulting in their degradation. Furthermore, we ablated atg5, a core gene of the autophagic machinery, specifically in myelinating glial cells in vivo by tamoxifen administration (plp-Cre ERT2 ; atg5 f/f ) and showed that myelin maintenance is perturbed, leading to PLP accumulation. Significant morphological defects in myelin membrane such as decompaction accompanied with increased axonal degeneration are observed. As a result, the mice exhibit behavioral deficits. In summary, our data highlight that the maintenance of adult myelin homeostasis in the CNS requires the involvement of a fully functional autophagic machinery.
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Affiliation(s)
- Niki Ktena
- School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | - Stefanos Ioannis Kaplanis
- School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | - Irina Kolotuev
- Electron Microscopy Facility (PME), University of Lausanne, Lausanne, Switzerland
| | | | - Emmanouela Kallergi
- Department of Fundamental Neurosciences (DNF), University of Lausanne, Lausanne, Switzerland
| | - Vasiliki Stavroulaki
- School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | | | - Maria Savvaki
- School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
| | - Domna Karagogeos
- School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece
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10
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Molina-Holgado E, Esteban PF, Arevalo-Martin Á, Moreno-Luna R, Molina-Holgado F, Garcia-Ovejero D. Endocannabinoid signaling in oligodendroglia. Glia 2022; 71:91-102. [PMID: 35411970 DOI: 10.1002/glia.24180] [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: 12/10/2021] [Revised: 03/10/2022] [Accepted: 03/28/2022] [Indexed: 12/11/2022]
Abstract
In the central nervous system, oligodendrocytes synthesize the myelin, a specialized membrane to wrap axons in a discontinuous way allowing a rapid saltatory nerve impulse conduction. Oligodendrocytes express a number of growth factors and neurotransmitters receptors that allow them to sense the environment and interact with neurons and other glial cells. Depending on the cell cycle stage, oligodendrocytes may respond to these signals by regulating their survival, proliferation, migration, and differentiation. Among these signals are the endocannabinoids, lipidic molecules synthesized from phospholipids in the plasma membrane in response to cell activation. Here, we discuss the evidence showing that oligodendrocytes express a full endocannabinoid signaling machinery involved in physiological oligodendrocyte functions that can be therapeutically exploited to promote remyelination in central nervous system pathologies.
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Affiliation(s)
- Eduardo Molina-Holgado
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos (SESCAM), Toledo, Spain
| | - Pedro F Esteban
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos (SESCAM), Toledo, Spain
| | - Ángel Arevalo-Martin
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos (SESCAM), Toledo, Spain
| | - Rafael Moreno-Luna
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos (SESCAM), Toledo, Spain
| | | | - Daniel Garcia-Ovejero
- Laboratory of Neuroinflammation, Hospital Nacional de Paraplejicos (SESCAM), Toledo, Spain
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11
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Joubert B, Petit-Pedrol M, Planagumà J, Mannara F, Radosevic M, Marsal M, Maudes E, García-Serra A, Aguilar E, Andrés-Bilbé A, Gasull X, Loza-Alvarez P, Sabater L, Rosenfeld MR, Dalmau J. Human CASPR2 antibodies reversibly alter memory and the CASPR2 protein complex. Ann Neurol 2022; 91:801-813. [PMID: 35253937 DOI: 10.1002/ana.26345] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVE The encephalitis associated with antibodies against contactin-associated protein-like 2 (CASPR2) is presumably antibody-mediated but the antibody effects and whether they cause behavioral alterations are not well-known. Here, we used a mouse model of patients' IgG transfer and super-resolution microscopy to demonstrate the antibody pathogenicity. METHODS IgG from patients with anti-CASPR2 encephalitis or healthy controls were infused into the cerebroventricular system of mice. The levels and colocalization of CASPR2 with transient axonal glycoprotein-1 (TAG1) were determined with Stimulated Emission Depletion (STED) microscopy (40-70μm lateral resolution). Hippocampal clusters of Kv1.1 voltage-gated potassium channels (VGKC) and GluA1-containing AMPA receptors were quantified with confocal microscopy. Behavioral alterations were assessed with standard behavioral paradigms. Cultured neurons were used to determine the levels of intracellular CASPR2 and TAG1 after exposure to patients' IgG. RESULTS Infusion of patients' IgG, but not control IgG, caused memory impairment along with hippocampal reduction of surface CASPR2 clusters and decreased CASPR2/TAG1 colocalization. In cultured neurons, patients' IgG led to an increase of intracellular CASPR2 without affecting TAG1, suggesting selective CASPR2 internalization. Additionally, mice infused with patients' IgG showed decreased levels of Kv1.1 and GluA1 (two CASPR2 regulated proteins). All these alterations and the memory deficit reverted to normal after removing patients' IgG. INTERPRETATION IgG from patients with anti-CASPR2 encephalitis cause reversible memory impairment, inhibit the interaction of CASPR2/TAG1, and decrease the levels of CASPR2 and related proteins (VGKC, AMPAR). These findings fulfill the postulates of antibody-mediated disease and provide a biological basis for antibody-removing treatment approaches. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Bastien Joubert
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Mar Petit-Pedrol
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Jesús Planagumà
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology (BIST) , Castelldefels (Barcelona), Spain
| | - Francesco Mannara
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Marija Radosevic
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Maria Marsal
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology (BIST) , Castelldefels (Barcelona), Spain
| | - Estibaliz Maudes
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Anna García-Serra
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Esther Aguilar
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Alba Andrés-Bilbé
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Neurophysiology Laboratory, Department of Biomedicine, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Neurophysiology Laboratory, Department of Biomedicine, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Pablo Loza-Alvarez
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology (BIST) , Castelldefels (Barcelona), Spain
| | - Lidia Sabater
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Myrna R Rosenfeld
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Josep Dalmau
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Catalan Institute for Research and Advanced Studies (ICREA), Barcelona, Spain
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12
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Simankova A, Bizen N, Saitoh S, Shibata S, Ohno N, Abe M, Sakimura K, Takebayashi H. Ddx20, DEAD box helicase 20, is essential for the differentiation of oligodendrocyte and maintenance of myelin gene expression. Glia 2021; 69:2559-2574. [PMID: 34231259 DOI: 10.1002/glia.24058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/17/2022]
Abstract
Oligodendrocytes form myelin sheaths that surround axons, contributing to saltatory conduction and proper central nervous system (CNS) function. Oligodendrocyte progenitor cells (OPCs) are generated during the embryonic stage and differentiate into myelinating oligodendrocytes postnatally. Ddx20 is a multifunctional, DEAD-box helicase involved in multiple cellular processes, including transcription, splicing, microRNA biogenesis, and translation. Although defects in each of these processes result in abnormal oligodendrocyte differentiation and myelination, the involvement of Ddx20 in oligodendrocyte terminal differentiation remains unknown. To address this question, we used Mbp-Cre mice to generate Ddx20 conditional knockout (cKO) mice to allow for the deletion of Ddx20 from mature oligodendrocytes. Mbp-Cre;Ddx20 cKO mice demonstrated small body sizes, behavioral abnormalities, muscle weakness, and short lifespans, with mortality by the age of 2 months old. Histological analyses demonstrated significant reductions in the number of mature oligodendrocytes and drastic reductions in the expression levels of myelin-associated mRNAs, such as Mbp and Plp at postnatal day 42. The number of OPCs did not change. A thin myelin layer was observed for large-diameter axons in Ddx20 cKO mice, based on electron microscopic analysis. A bromodeoxyuridine (BrdU) labeling experiment demonstrated that terminal differentiation was perturbed from ages 2 weeks to 7 weeks in the CNS of Mbp-Cre;Ddx20 cKO mice. The activation of mitogen-activated protein (MAP) kinase, which promotes myelination, was downregulated in the Ddx20 cKO mice based on immunohistochemical detection. These results indicate that Ddx20 is an essential factor for terminal differentiation of oligodendrocytes and maintenance of myelin gene expression.
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Affiliation(s)
- Anna Simankova
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Norihisa Bizen
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Sei Saitoh
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Biomedical Molecular Sciences (Anatomy II), Fujita Health University School of Medicine, Toyoake, Japan
| | - Shinsuke Shibata
- Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan.,Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.,Center for Coordination of Research Facilities, Niigata University, Niigata, Japan
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13
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Kalafatakis I, Savvaki M, Velona T, Karagogeos D. Implication of Contactins in Demyelinating Pathologies. Life (Basel) 2021; 11:life11010051. [PMID: 33451101 PMCID: PMC7828632 DOI: 10.3390/life11010051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/09/2021] [Accepted: 01/11/2021] [Indexed: 12/19/2022] Open
Abstract
Demyelinating pathologies comprise of a variety of conditions where either central or peripheral myelin is attacked, resulting in white matter lesions and neurodegeneration. Myelinated axons are organized into molecularly distinct domains, and this segregation is crucial for their proper function. These defined domains are differentially affected at the different stages of demyelination as well as at the lesion and perilesion sites. Among the main players in myelinated axon organization are proteins of the contactin (CNTN) group of the immunoglobulin superfamily (IgSF) of cell adhesion molecules, namely Contactin-1 and Contactin-2 (CNTN1, CNTN2). The two contactins perform their functions through intermolecular interactions, which are crucial for myelinated axon integrity and functionality. In this review, we focus on the implication of these two molecules as well as their interactors in demyelinating pathologies in humans. At first, we describe the organization and function of myelinated axons in the central (CNS) and the peripheral (PNS) nervous system, further analyzing the role of CNTN1 and CNTN2 as well as their interactors in myelination. In the last section, studies showing the correlation of the two contactins with demyelinating pathologies are reviewed, highlighting the importance of these recognition molecules in shaping the function of the nervous system in multiple ways.
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14
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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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15
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Suter TACS, Blagburn SV, Fisher SE, Anderson-Keightly HM, D'Elia KP, Jaworski A. TAG-1 Multifunctionality Coordinates Neuronal Migration, Axon Guidance, and Fasciculation. Cell Rep 2020; 30:1164-1177.e7. [PMID: 31995756 PMCID: PMC7049094 DOI: 10.1016/j.celrep.2019.12.085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/25/2019] [Accepted: 12/22/2019] [Indexed: 11/03/2022] Open
Abstract
Neuronal migration, axon fasciculation, and axon guidance need to be closely coordinated for neural circuit assembly. Spinal motor neurons (MNs) face unique challenges during development because their cell bodies reside within the central nervous system (CNS) and their axons project to various targets in the body periphery. The molecular mechanisms that contain MN somata within the spinal cord while allowing their axons to exit the CNS and navigate to their final destinations remain incompletely understood. We find that the MN cell surface protein TAG-1 anchors MN cell bodies in the spinal cord to prevent their emigration, mediates motor axon fasciculation during CNS exit, and guides motor axons past dorsal root ganglia. TAG-1 executes these varied functions in MN development independently of one another. Our results identify TAG-1 as a key multifunctional regulator of MN wiring that coordinates neuronal migration, axon fasciculation, and axon guidance. Suter et al. demonstrate that the motor neuron cell surface molecule TAG-1 confines motor neurons to the central nervous system, promotes motor axon fasciculation, and steers motor axons past inappropriate targets. This study highlights how a single cell adhesion molecule coordinates multiple steps in neuronal wiring through partially divergent mechanisms.
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Affiliation(s)
- Tracey A C S Suter
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Sara V Blagburn
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Sophie E Fisher
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | | | - Kristen P D'Elia
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Department of Biology, Providence College, Providence, RI 02918, USA
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA.
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16
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Kalafatakis I, Kalafatakis K, Tsimpolis A, Giannakeas N, Tsipouras M, Tzallas A, Karagogeos D. Using the Allen gene expression atlas of the adult mouse brain to gain further insight into the physiological significance of TAG-1/Contactin-2. Brain Struct Funct 2020; 225:2045-2056. [PMID: 32601750 DOI: 10.1007/s00429-020-02108-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 06/21/2020] [Indexed: 12/11/2022]
Abstract
The anatomic gene expression atlas (AGEA) of the adult mouse brain of the Allen Institute for Brain Science is a transcriptome-based atlas of the adult C57Bl/6 J mouse brain, based on the extensive in situ hybridization dataset of the Institute. This spatial mapping of the gene expression levels of mice under baseline conditions could assist in the formation of new, reasonable transcriptome-derived hypotheses on brain structure and underlying biochemistry, which could also have functional implications. The aim of this work is to use the data of the AGEA (in combination with Tabula Muris, a compendium of single cell transcriptome data collected from mice, enabling direct and controlled comparison of gene expression among cell types) to provide further insights into the physiology of TAG-1/Contactin-2 and its interactions, by presenting the expression of the corresponding gene across the adult mouse brain under baseline conditions and to investigate any spatial genomic correlations between TAG-1/Contactin-2 and its interacting proteins and markers of mature and immature oligodendrocytes, based on the pre-existing experimental or bibliographical evidence. The across-brain correlation analysis on the gene expression intensities showed a positive spatial correlation of TAG-1/Contactin-2 with the gene expression of Plp1, Myrf, Mbp, Mog, Cldn11, Bace1, Kcna1, Kcna2, App and Nfasc and a negative spatial correlation with the gene expression of Cspg4, Pdgfra, L1cam, Ncam1, Ncam2 and Ptprz1. Spatially correlated genes are mainly expressed by mature oligodendrocytes (like Cntn2), while spatially anticorrelated genes are mainly expressed by oligodendrocyte precursor cells. According to the data presented in this work, we propose that even though Contactin-2 expression during development correlates with high plasticity events, such as neuritogenesis, in adulthood it correlates with pathways characterized by low plasticity.
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Affiliation(s)
- Ilias Kalafatakis
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece.
| | - Konstantinos Kalafatakis
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Alexandros Tsimpolis
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece
| | - Nikos Giannakeas
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Markos Tsipouras
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Alexandros Tzallas
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Domna Karagogeos
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece
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17
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Theodosiou T, Papanikolaou N, Savvaki M, Bonetto G, Maxouri S, Fakoureli E, Eliopoulos AG, Tavernarakis N, Amoutzias GD, Pavlopoulos GA, Aivaliotis M, Nikoletopoulou V, Tzamarias D, Karagogeos D, Iliopoulos I. UniProt-Related Documents (UniReD): assisting wet lab biologists in their quest on finding novel counterparts in a protein network. NAR Genom Bioinform 2020; 2:lqaa005. [PMID: 33575553 PMCID: PMC7671407 DOI: 10.1093/nargab/lqaa005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/20/2020] [Accepted: 01/31/2020] [Indexed: 02/04/2023] Open
Abstract
The in-depth study of protein–protein interactions (PPIs) is of key importance for understanding how cells operate. Therefore, in the past few years, many experimental as well as computational approaches have been developed for the identification and discovery of such interactions. Here, we present UniReD, a user-friendly, computational prediction tool which analyses biomedical literature in order to extract known protein associations and suggest undocumented ones. As a proof of concept, we demonstrate its usefulness by experimentally validating six predicted interactions and by benchmarking it against public databases of experimentally validated PPIs succeeding a high coverage. We believe that UniReD can become an important and intuitive resource for experimental biologists in their quest for finding novel associations within a protein network and a useful tool to complement experimental approaches (e.g. mass spectrometry) by producing sorted lists of candidate proteins for further experimental validation. UniReD is available at http://bioinformatics.med.uoc.gr/unired/
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Affiliation(s)
- Theodosios Theodosiou
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece
| | - Nikolaos Papanikolaou
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece
| | - Maria Savvaki
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
| | - Giulia Bonetto
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece
| | - Stella Maxouri
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece.,Medical School of Patras University, Laboratory of General Biology, Asklipiou 1, 26500 Rio Patras, Greece
| | - Eirini Fakoureli
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece
| | - Aristides G Eliopoulos
- Department of Biology, Medical School, National and Kapodistrian University of Athens, Mikras Asias 75, 11527 Athens, Greece
| | - Nektarios Tavernarakis
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
| | - Grigoris D Amoutzias
- Bioinformatics Laboratory, Department of Biochemistry and Biotechnology, University of Thessaly, Larisa 41500, Greece
| | - Georgios A Pavlopoulos
- Institute for Fundamental Biomedical Research, BSRC "Alexander Fleming", 34 Fleming Street, 16672 Vari, Greece
| | - Michalis Aivaliotis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece.,Laboratory of Biological Chemistry, Faculty of Health Sciences, School of Medicine, Aristotle University of Thessaloniki, GR-54124, Thessaloniki, Greece.,Functional Proteomics and Systems Biology (FunPATh), Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, Thessaloniki, 10th km Thessaloniki-Thermi Rd, P.O.Box 8318, GR 57001, Greece
| | - Vasiliki Nikoletopoulou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
| | - Dimitris Tzamarias
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
| | - Domna Karagogeos
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
| | - Ioannis Iliopoulos
- University of Crete, School of Medicine, Department of Basic Sciences, Heraklion 71003, Crete, Greece
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18
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Yu Y, Luo X, Li C, Ding F, Wang M, Xie M, Yu Z, Ransom BR, Wang W. Microglial Hv1 proton channels promote white matter injuries after chronic hypoperfusion in mice. J Neurochem 2019; 152:350-367. [PMID: 31769505 DOI: 10.1111/jnc.14925] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 11/16/2019] [Accepted: 11/19/2019] [Indexed: 12/30/2022]
Abstract
Microglia are critical in damage/repair processes during ischemic white matter injury (WMI). Voltage-gated proton channel (Hv1) is expressed in microglia and contributes to nicotinamide adenine dinucleotide phosphate oxidase complex-dependent production of reactive oxygen species (ROS). Recent findings have shown that Hv1 is involved in regulating luminal pH of M1-polarized microglial phagosomes and inhibits endocytosis in microglia. We previously reported that Hv1 facilitated production of ROS and pro-inflammatory cytokines in microglia and enhanced damage to oligodendrocyte progenitor cells from oxygen and glucose deprivation. To investigate the role of Hv1 in hypoperfusion-induced WMI, we employed mice that were genetically devoid of Hv1 (Hv1-/- ), as well as a model of subcortical vascular dementia via bilateral common carotid artery stenosis. Integrity of myelin was assessed using immunofluorescent staining and transmission electron microscopy, while cognitive impairment was assessed using an eight-arm radial maze test. Hv1 deficiency was found to attenuate bilateral common carotid artery stenosis-induced disruption of white matter integrity and impairment of working memory. Immunofluorescent staining and western blotting were used to assay changes in oligodendrocytes, OPCs, and microglial polarization. Compared with that in wild-type (WT) mice, Hv1-/- mice exhibited reduced ROS generation, decreased pro-inflammatory cytokines production, and an M2-dominant rather than M1-dominant microglial polarization. Furthermore, Hv1-/- mice exhibited enhanced OPC proliferation and differentiation into oligodendrocytes. Results of mouse-derived microglia-OPC co-cultures suggested that PI3K/Akt signaling was involved in Hv1-deficiency-induced M2-type microglial polarization and concomitant OPC differentiation. These results suggest that microglial Hv1 is a promising therapeutic target for reducing ischemic WMI and cognitive impairment.
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Affiliation(s)
- Ying Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiang Luo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunyu Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fengfei Ding
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minghuan Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiyuan Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bruce R Ransom
- Department of Neurology, University of Washington School of Medicine HMC, Seattle, WA, USA
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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19
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Grubman A, Chew G, Ouyang JF, Sun G, Choo XY, McLean C, Simmons RK, Buckberry S, Vargas-Landin DB, Poppe D, Pflueger J, Lister R, Rackham OJL, Petretto E, Polo JM. A single-cell atlas of entorhinal cortex from individuals with Alzheimer's disease reveals cell-type-specific gene expression regulation. Nat Neurosci 2019; 22:2087-2097. [PMID: 31768052 DOI: 10.1038/s41593-019-0539-4] [Citation(s) in RCA: 504] [Impact Index Per Article: 100.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is currently little information available about how individual cell types contribute to Alzheimer's disease. Here we applied single-nucleus RNA sequencing to entorhinal cortex samples from control and Alzheimer's disease brains (n = 6 per group), yielding a total of 13,214 high-quality nuclei. We detail cell-type-specific gene expression patterns, unveiling how transcriptional changes in specific cell subpopulations are associated with Alzheimer's disease. We report that the Alzheimer's disease risk gene APOE is specifically repressed in Alzheimer's disease oligodendrocyte progenitor cells and astrocyte subpopulations and upregulated in an Alzheimer's disease-specific microglial subopulation. Integrating transcription factor regulatory modules with Alzheimer's disease risk loci revealed drivers of cell-type-specific state transitions towards Alzheimer's disease. For example, transcription factor EB, a master regulator of lysosomal function, regulates multiple disease genes in a specific Alzheimer's disease astrocyte subpopulation. These results provide insights into the coordinated control of Alzheimer's disease risk genes and their cell-type-specific contribution to disease susceptibility. These results are available at http://adsn.ddnetbio.com.
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Affiliation(s)
- Alexandra Grubman
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Gabriel Chew
- Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Medical School, Singapore, Singapore
| | - John F Ouyang
- Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Guizhi Sun
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Xin Yi Choo
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
- Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Catriona McLean
- Victorian Brain Bank, Florey Institute of Neurosciences, Parkville, Victoria, Australia
| | - Rebecca K Simmons
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia, Australia
- The Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
| | - Sam Buckberry
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia, Australia
- The Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
| | - Dulce B Vargas-Landin
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia, Australia
- The Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
| | - Daniel Poppe
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia, Australia
- The Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
| | - Jahnvi Pflueger
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia, Australia
- The Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
| | - Ryan Lister
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia, Australia
- The Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
| | - Owen J L Rackham
- Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Medical School, Singapore, Singapore.
| | - Enrico Petretto
- Program in Cardiovascular and Metabolic Disorders, Duke-National University of Singapore Medical School, Singapore, Singapore.
| | - Jose M Polo
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia.
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia.
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20
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Kastriti ME, Stratigi A, Mariatos D, Theodosiou M, Savvaki M, Kavkova M, Theodorakis K, Vidaki M, Zikmund T, Kaiser J, Adameyko I, Karagogeos D. Ablation of CNTN2+ Pyramidal Neurons During Development Results in Defects in Neocortical Size and Axonal Tract Formation. Front Cell Neurosci 2019; 13:454. [PMID: 31749685 PMCID: PMC6844266 DOI: 10.3389/fncel.2019.00454] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/23/2019] [Indexed: 01/22/2023] Open
Abstract
Corticothalamic axons express Contactin-2 (CNTN2/TAG-1), a neuronal recognition molecule of the immunoglobulin superfamily involved in neurogenesis, neurite outgrowth, and fasciculation. TAG-1, which is expressed transiently by cortical pyramidal neurons during embryonic development, has been shown to be fundamental for axonal recognition, cellular migration, and neuronal proliferation in the developing cortex. Although Tag-1−/− mice do not exhibit any obvious defects in the corticofugal system, the role of TAG-1+ neurons during the development of the cortex remains elusive. We have generated a mouse model expressing EGFP under the Tag-1 promoter and encompassing the coding sequence of Diptheria Toxin subunit A (DTA) under quiescence with no effect on the expression of endogenous Tag-1. We show that while the line recapitulates the expression pattern of the molecule, it highlights an extended expression in the forebrain, including multiple axonal tracts and neuronal populations, both spatially and temporally. Crossing these mice to the Emx1-Cre strain, we ablated the vast majority of TAG-1+ cortical neurons. Among the observed defects were a significantly smaller cortex, a reduction of corticothalamic axons as well as callosal and commissural defects. Such defects are common in neurodevelopmental disorders, thus this mouse could serve as a useful model to study physiological and pathophysiological cortical development.
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Affiliation(s)
- Maria Eleni Kastriti
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Aikaterini Stratigi
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece.,Laboratory of Neurophysiology, Université Libre de Bruxelles, UNI, Brussels, Belgium
| | - Dimitris Mariatos
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece
| | - Marina Theodosiou
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece.,Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece
| | - Michaela Kavkova
- CEITEC-Central European Institute of Technology, Brno University of Technology, Brno, Czechia
| | - Kostas Theodorakis
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece
| | - Marina Vidaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece.,The Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Tomas Zikmund
- CEITEC-Central European Institute of Technology, Brno University of Technology, Brno, Czechia
| | - Jozef Kaiser
- CEITEC-Central European Institute of Technology, Brno University of Technology, Brno, Czechia
| | - Igor Adameyko
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece.,Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology, Heraklion, Greece
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21
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Kagiava A, Richter J, Tryfonos C, Karaiskos C, Heslegrave AJ, Sargiannidou I, Rossor AM, Zetterberg H, Reilly MM, Christodoulou C, Kleopa KA. Gene replacement therapy after neuropathy onset provides therapeutic benefit in a model of CMT1X. Hum Mol Genet 2019; 28:3528-3542. [PMID: 31411673 DOI: 10.1093/hmg/ddz199] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 12/22/2022] Open
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X), one of the commonest forms of inherited demyelinating neuropathy, results from GJB1 gene mutations causing loss of function of the gap junction protein connexin32 (Cx32). The aim of this study was to examine whether delayed gene replacement therapy after the onset of peripheral neuropathy can provide a therapeutic benefit in the Gjb1-null/Cx32 knockout model of CMT1X. After delivery of the LV-Mpz.GJB1 lentiviral vector by a single lumbar intrathecal injection into 6-month-old Gjb1-null mice, we confirmed expression of Cx32 in lumbar roots and sciatic nerves correctly localized at the paranodal myelin areas. Gjb1-null mice treated with LV-Mpz.GJB1 compared with LV-Mpz.Egfp (mock) vector at the age of 6 months showed improved motor performance at 8 and 10 months. Furthermore, treated mice showed increased sciatic nerve conduction velocities, improvement of myelination and reduced inflammation in lumbar roots and peripheral nerves at 10 months of age, along with enhanced quadriceps muscle innervation. Plasma neurofilament light (NEFL) levels, a clinically relevant biomarker, were also ameliorated in fully treated mice. Intrathecal gene delivery after the onset of peripheral neuropathy offers a significant therapeutic benefit in this disease model, providing a proof of principle for treating patients with CMT1X at different ages.
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Affiliation(s)
- A Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - J Richter
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Tryfonos
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - C Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A J Heslegrave
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - I Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - A M Rossor
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - H Zetterberg
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
- UK Dementia Research Institute at UCL, London, United Kingdom
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - M M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - C Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - K A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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22
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Saint-Martin M, Pieters A, Déchelotte B, Malleval C, Pinatel D, Pascual O, Karagogeos D, Honnorat J, Pellier-Monnin V, Noraz N. Impact of anti-CASPR2 autoantibodies from patients with autoimmune encephalitis on CASPR2/TAG-1 interaction and Kv1 expression. J Autoimmun 2019; 103:102284. [PMID: 31176559 DOI: 10.1016/j.jaut.2019.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/08/2019] [Accepted: 05/14/2019] [Indexed: 12/19/2022]
Abstract
Autoantibodies against CASPR2 (contactin-associated protein-like 2) have been linked to autoimmune limbic encephalitis that manifests with memory disorders and temporal lobe seizures. According to the growing number of data supporting a role for CASPR2 in neuronal excitability, CASPR2 forms a molecular complex with transient axonal glycoprotein-1 (TAG-1) and shaker-type voltage-gated potassium channels (Kv1.1 and Kv1.2) in compartments critical for neuronal activity and is required for Kv1 proper positioning. Whereas the perturbation of these functions could explain the symptoms observed in patients, the pathogenic role of anti-CASPR2 antibodies has been poorly studied. In the present study, we find that patient autoantibodies alter Caspr2 distribution at the cell membrane promoting cluster formation. We confirm in a HEK cellular model that the anti-CASPR2 antibodies impede CASPR2/TAG-1 interaction and we identify the domains of CASPR2 and TAG-1 taking part in this interaction. Moreover, introduction of CASPR2 into HEK cells induces a marked increase of the level of Kv1.2 surface expression and in cultures of hippocampal neurons Caspr2-positive inhibitory neurons appear to specifically express high levels of Kv1.2. Importantly, in both cellular models, anti-CASPR2 patient autoAb increase Kv1.2 expression. These results provide new insights into the pathogenic role of autoAb in the disease.
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Affiliation(s)
- Margaux Saint-Martin
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Alanah Pieters
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Benoît Déchelotte
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Céline Malleval
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Delphine Pinatel
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Olivier Pascual
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Domna Karagogeos
- University of Crete Medical School and IMBB-FORTH, Heraklion, Crete GR, 70013, Greece
| | - Jérôme Honnorat
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France; Hospices Civils de Lyon, Lyon, F-69000, France
| | - Véronique Pellier-Monnin
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France
| | - Nelly Noraz
- INSERM U1217, Institut NeuroMyoGène, Lyon, F-69000, France; CNRS UMR5310, Institut NeuroMyoGène, Lyon, F-69000, France; University Claude Bernard Lyon 1, Lyon, F-69000, France.
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23
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Bonetto G, Hivert B, Goutebroze L, Karagogeos D, Crépel V, Faivre-Sarrailh C. Selective Axonal Expression of the Kv1 Channel Complex in Pre-myelinated GABAergic Hippocampal Neurons. Front Cell Neurosci 2019; 13:222. [PMID: 31164806 PMCID: PMC6535494 DOI: 10.3389/fncel.2019.00222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/02/2019] [Indexed: 01/01/2023] Open
Abstract
In myelinated fibers, the voltage-gated sodium channels Nav1 are concentrated at the nodal gap to ensure the saltatory propagation of action potentials. The voltage-gated potassium channels Kv1 are segregated at the juxtaparanodes under the compact myelin sheath and may stabilize axonal conduction. It has been recently reported that hippocampal GABAergic neurons display high density of Nav1 channels remarkably in clusters along the axon before myelination (Freeman et al., 2015). In inhibitory neurons, the Nav1 channels are trapped by the ankyrinG scaffold at the axon initial segment (AIS) as observed in pyramidal and granule neurons, but are also forming “pre-nodes,” which may accelerate conduction velocity in pre-myelinated axons. However, the distribution of the Kv1 channels along the pre-myelinated inhibitory axons is still unknown. In the present study, we show that two subtypes of hippocampal GABAergic neurons, namely the somatostatin and parvalbumin positive cells, display a selective high expression of Kv1 channels at the AIS and all along the unmyelinated axons. These inhibitory axons are also highly enriched in molecules belonging to the juxtaparanodal Kv1 complex, including the cell adhesion molecules (CAMs) TAG-1, Caspr2, and ADAM22 and the scaffolding protein 4.1B. Here, taking advantage of hippocampal cultures from 4.1B and TAG-1 knock-out mice, we observed that 4.1B is required for the proper positioning of Caspr2 and TAG-1 along the distal axon, and that TAG-1 deficiency induces alterations in the axonal distribution of Caspr2. However, the axonal expression of Kv1 channels and clustering of ankyrinG were not modified. In conclusion, this study allowed the analysis of the hierarchy between channels, CAMs and scaffolding proteins for their expression along hippocampal inhibitory axons before myelination. The early steps of channel compartmentalization preceding myelination may be crucial for stabilizing nerve impulses switching from a continuous to saltatory conduction during network development.
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Affiliation(s)
- Giulia Bonetto
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
| | - Bruno Hivert
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
| | - Laurence Goutebroze
- INSERM UMR-S 1270, Institut du Fer à Moulin, Faculté des Sciences et Ingénierie, Sorbonne Université, Paris, France
| | - Domna Karagogeos
- Department of Basic Sciences, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, University of Crete Medical School - University of Crete, Heraklion, Greece
| | - Valérie Crépel
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
| | - Catherine Faivre-Sarrailh
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
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24
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Petri J, Syed MH, Rey S, Klämbt C. Non-Cell-Autonomous Function of the GPI-Anchored Protein Undicht during Septate Junction Assembly. Cell Rep 2019; 26:1641-1653.e4. [DOI: 10.1016/j.celrep.2019.01.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/12/2018] [Accepted: 01/10/2019] [Indexed: 11/26/2022] Open
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25
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Saint-Martin M, Joubert B, Pellier-Monnin V, Pascual O, Noraz N, Honnorat J. Contactin-associated protein-like 2, a protein of the neurexin family involved in several human diseases. Eur J Neurosci 2018; 48:1906-1923. [PMID: 30028556 DOI: 10.1111/ejn.14081] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/08/2018] [Accepted: 07/02/2018] [Indexed: 12/11/2022]
Abstract
Contactin-associated protein-like 2 (CASPR2) is a cell adhesion protein of the neurexin family. Proteins of this family have been shown to play a role in the development of the nervous system, in synaptic functions, and in neurological diseases. Over recent years, CASPR2 function has gained an increasing interest as demonstrated by the growing number of publications. Here, we gather published data to comprehensively review CASPR2 functions within the nervous system in relation to CASPR2-related diseases in humans. On the one hand, studies on Cntnap2 (coding for CASPR2) knockout mice revealed its role during development, especially, in setting-up the inhibitory network. Consistent with this result, mutations in the CNTNAP2 gene coding for CASPR2 in human have been identified in neurodevelopmental disorders such as autism, intellectual disability, and epilepsy. On the other hand, CASPR2 was shown to play a role beyond development, in the localization of voltage-gated potassium channel (VGKC) complex that is composed of TAG-1, Kv1.1, and Kv1.2. This complex was found in several subcellular compartments essential for action potential propagation: the node of Ranvier, the axon initial segment, and the synapse. In line with a role of CASPR2 in the mature nervous system, neurological autoimmune diseases have been described in patients without neurodevelopmental disorders but with antibodies directed against CASPR2. These autoimmune diseases were of two types: central with memory disorders and temporal lobe seizures, or peripheral with muscular hyperactivity. Overall, we review the up-to-date knowledge on CASPR2 function and pinpoint confused or lacking information that will need further investigation.
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Affiliation(s)
- Margaux Saint-Martin
- Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Bastien Joubert
- Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique, Bron, France
| | - Véronique Pellier-Monnin
- Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Olivier Pascual
- Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Nelly Noraz
- Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Jérôme Honnorat
- Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique, Bron, France
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26
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Kagiava A, Karaiskos C, Richter J, Tryfonos C, Lapathitis G, Sargiannidou I, Christodoulou C, Kleopa KA. Intrathecal gene therapy in mouse models expressing CMT1X mutations. Hum Mol Genet 2018; 27:1460-1473. [PMID: 29462293 DOI: 10.1093/hmg/ddy056] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/10/2018] [Indexed: 11/14/2022] Open
Abstract
Gap junction beta-1 (GJB1) gene mutations affecting the gap junction protein connexin32 (Cx32) cause the X-linked Charcot-Marie-Tooth disease (CMT1X), a common inherited neuropathy. Targeted expression of virally delivered Cx32 in Schwann cells following intrathecal injection of lentiviral vectors in the Cx32 knockout (KO) mouse model of the disease has led to morphological and functional improvement. To examine whether this approach could be effective in CMT1X patients expressing different Cx32 mutants, we treated transgenic Cx32 KO mice expressing the T55I, R75W or N175D CMT1X mutations. All three mutants were localized in the perinuclear compartment of myelinating Schwann cells consistent with retention in the ER (T55I) or Golgi (R75W, N175D) and loss of physiological expression in the non-compact myelin. Following intrathecal delivery of the GJB1 gene we detected the virally delivered wild-type (WT) Cx32 in non-compact myelin of T55I KO mice, but only rarely in N175D KO or R75W KO mice, suggesting dominant-negative effects of the R75W and N175D mutants but not of the T55I mutant on co-expressed WT Cx32. GJB1 treated T55I KO mice showed improved motor performance, lower ratios of abnormally myelinated fibers and reduction of inflammatory cells in spinal roots and peripheral nerves compared with mock-treated littermates. Either partial (N175D KO) or no (R75W KO) improvement was observed in the other two mutant lines. Thus, certain CMT1X mutants may interfere with gene addition therapy for CMT1X. Whereas gene addition can be used for non-interfering CMT1X mutations, further studies will be needed to develop treatments for patients harboring interfering mutations.
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Affiliation(s)
- A Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - C Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - J Richter
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - C Tryfonos
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - G Lapathitis
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - I Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - C Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
| | - K A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, 1683 Nicosia, Cyprus
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Zoupi L, Savvaki M, Kalemaki K, Kalafatakis I, Sidiropoulou K, Karagogeos D. The function of contactin-2/TAG-1 in oligodendrocytes in health and demyelinating pathology. Glia 2017; 66:576-591. [PMID: 29165835 DOI: 10.1002/glia.23266] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/09/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022]
Abstract
The oligodendrocyte maturation process and the transition from the pre-myelinating to the myelinating state are extremely important during development and in pathology. In the present study, we have investigated the role of the cell adhesion molecule CNTN2/TAG-1 on oligodendrocyte proliferation, differentiation, myelination, and function during development and under pathological conditions. With the combination of in vivo, in vitro, ultrastructural, and electrophysiological methods, we have mapped the expression of CNTN2 protein in the oligodendrocyte lineage during the different stages of myelination and its involvement on oligodendrocyte maturation, branching, myelin-gene expression, myelination, and axonal function. The cuprizone model of central nervous system demyelination was further used to assess CNTN2 in pathology. During development, CNTN2 can transiently affect the expression levels of myelin and myelin-regulating genes, while its absence results in reduced oligodendrocyte branching, hypomyelination of fiber tracts and impaired axonal conduction. In pathology, CNTN2 absence does not affect the extent of de- and remyelination. However during remyelination, a novel, CNTN2-independent mechanism is revealed that is able to recluster voltage gated potassium channels (VGKCs) resulting in the improvement of fiber conduction.
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Affiliation(s)
- Lida Zoupi
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Katerina Kalemaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Ilias Kalafatakis
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Kyriaki Sidiropoulou
- Neurophysiology & Behavior Laboratory, Department of Biology, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
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28
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Kleinecke S, Richert S, de Hoz L, Brügger B, Kungl T, Asadollahi E, Quintes S, Blanz J, McGonigal R, Naseri K, Sereda MW, Sachsenheimer T, Lüchtenborg C, Möbius W, Willison H, Baes M, Nave KA, Kassmann CM. Peroxisomal dysfunctions cause lysosomal storage and axonal Kv1 channel redistribution in peripheral neuropathy. eLife 2017; 6. [PMID: 28470148 PMCID: PMC5417850 DOI: 10.7554/elife.23332] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 04/06/2017] [Indexed: 12/12/2022] Open
Abstract
Impairment of peripheral nerve function is frequent in neurometabolic diseases, but mechanistically not well understood. Here, we report a novel disease mechanism and the finding that glial lipid metabolism is critical for axon function, independent of myelin itself. Surprisingly, nerves of Schwann cell-specific Pex5 mutant mice were unaltered regarding axon numbers, axonal calibers, and myelin sheath thickness by electron microscopy. In search for a molecular mechanism, we revealed enhanced abundance and internodal expression of axonal membrane proteins normally restricted to juxtaparanodal lipid-rafts. Gangliosides were altered and enriched within an expanded lysosomal compartment of paranodal loops. We revealed the same pathological features in a mouse model of human Adrenomyeloneuropathy, preceding disease-onset by one year. Thus, peroxisomal dysfunction causes secondary failure of local lysosomes, thereby impairing the turnover of gangliosides in myelin. This reveals a new aspect of axon-glia interactions, with Schwann cell lipid metabolism regulating the anchorage of juxtaparanodal Kv1-channels. DOI:http://dx.doi.org/10.7554/eLife.23332.001 Nerve cells transmit messages along their length in the form of electrical signals. Much like an electrical wire, the nerve fiber or axon is coated by a multiple-layered insulation, called the myelin sheath. However, unlike electrical insulation, the myelin sheath is regularly interrupted to expose short regions of the underlying nerve. These exposed regions and the adjacent regions underneath the myelin contain ion channels that help to propagate electrical signals along the axon. Peroxisomes are compartments in animal cells that process fats. Genetic mutations that prevent peroxisomes from working properly can lead to diseases where the nerves cannot transmit signals correctly. This is thought to be because the nerves lose their myelin sheath, which largely consists of fatty molecules. The nerves outside of the brain and spinal cord are known as peripheral nerves. Kleinecke et al. have now analyzed peripheral nerves from mice that had one of three different genetic mutations, preventing their peroxisomes from working correctly. Even in cases where the mutation severely impaired nerve signaling, the peripheral nerves retained their myelin sheath. The peroxisome mutations did affect a particular type of potassium ion channel and the anchor proteins that hold these channels in place. The role of these potassium ion channels is not fully known, but normally they are only found close to regions of the axon that are not coated by myelin. However, the peroxisome mutations meant that the channels and their protein anchors were now also located along the myelinated segments of the nerve’s axons. This redistribution of the potassium ion channels likely contributes to the peripheral nerves being unable to signal properly. In addition, Kleinecke et al. found that disrupting the peroxisomes also affected another cell compartment, called the lysosome, in the nerve cells that insulate axons with myelin sheaths. Lysosomes help to break down unwanted fat molecules. Mutant mice had more lysosomes than normal, but these lysosomes did not work efficiently. This caused the nerve cells to store more of certain types of molecules, including molecules called glycolipids that stabilize protein anchors, which hold the potassium channels in place. A likely result is that protein anchors that would normally be degraded are not, leading to the potassium channels appearing inappropriately throughout the nerve. Future work is now needed to investigate whether peroxisomal diseases cause similar changes in the brain. The results presented by Kleinecke et al. also suggest that targeting the lysosomes or the potassium channels could present new ways to treat disorders of the peroxisomes. DOI:http://dx.doi.org/10.7554/eLife.23332.002
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Affiliation(s)
- Sandra Kleinecke
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sarah Richert
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Livia de Hoz
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Britta Brügger
- University of Heidelberg, Biochemistry Center (BZH), Heidelberg, Germany
| | - Theresa Kungl
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ebrahim Asadollahi
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Susanne Quintes
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Judith Blanz
- Unit of Molecular Cell Biology and Transgenic, Institute of Biochemistry, University of Kiel, Kiel, Germany
| | - Rhona McGonigal
- Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Kobra Naseri
- Birjand University of Medical Sciences, Birjand, Iran
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Timo Sachsenheimer
- University of Heidelberg, Biochemistry Center (BZH), Heidelberg, Germany
| | | | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hugh Willison
- Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Myriam Baes
- Department of Pharmaceutical and Pharmacological Sciences, Cell Metabolism, KU Leuven- University of Leuven, Leuven, Belgium
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Celia Michèle Kassmann
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Gennarini G, Bizzoca A, Picocci S, Puzzo D, Corsi P, Furley AJW. The role of Gpi-anchored axonal glycoproteins in neural development and neurological disorders. Mol Cell Neurosci 2016; 81:49-63. [PMID: 27871938 DOI: 10.1016/j.mcn.2016.11.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 01/06/2023] Open
Abstract
This review article focuses on the Contactin (CNTN) subset of the Immunoglobulin supergene family (IgC2/FNIII molecules), whose components share structural properties (the association of Immunoglobulin type C2 with Fibronectin type III domains), as well as a general role in cell contact formation and axonal growth control. IgC2/FNIII molecules include 6 highly related components (CNTN 1-6), associated with the cell membrane via a Glycosyl Phosphatidyl Inositol (GPI)-containing lipid tail. Contactin 1 and Contactin 2 share ~50 (49.38)% identity at the aminoacid level. They are components of the cell surface, from which they may be released in soluble forms. They bind heterophilically to multiple partners in cis and in trans, including members of the related L1CAM family and of the Neurexin family Contactin-associated proteins (CNTNAPs or Casprs). Such interactions are important for organising the neuronal membrane, as well as for modulating the growth and pathfinding of axon tracts. In addition, they also mediate the functional maturation of axons by promoting their interactions with myelinating cells at the nodal, paranodal and juxtaparanodal regions. Such interactions also mediate differential ionic channels (both Na+ and K+) distribution, which is of critical relevance in the generation of the peak-shaped action potential. Indeed, thanks to their interactions with Ankyrin G, Na+ channels map within the nodal regions, where they drive axonal depolarization. However, no ionic channels are found in the flanking Contactin1-containing paranodal regions, where CNTN1 interactions with Caspr1 and with the Ig superfamily component Neurofascin 155 in cis and in trans, respectively, build a molecular barrier between the node and the juxtaparanode. In this region K+ channels are clustered, depending upon molecular interactions with Contactin 2 and with Caspr2. In addition to these functions, the Contactins appear to have also a role in degenerative and inflammatory disorders: indeed Contactin 2 is involved in neurodegenerative disorders with a special reference to the Alzheimer disease, given its ability to work as a ligand of the Alzheimer Precursor Protein (APP), which results in increased Alzheimer Intracellular Domain (AICD) release in a γ-secretase-dependent manner. On the other hand Contactin 1 drives Notch signalling activation via the Hes pathway, which could be consistent with its ability to modulate neuroinflammation events, and with the possibility that Contactin 1-dependent interactions may participate to the pathogenesis of the Multiple Sclerosis and of other inflammatory disorders.
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Affiliation(s)
- Gianfranco Gennarini
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, Medical School, University of Bari Policlinico. Piazza Giulio Cesare. I-70124 Bari, Italy.
| | - Antonella Bizzoca
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, Medical School, University of Bari Policlinico. Piazza Giulio Cesare. I-70124 Bari, Italy
| | - Sabrina Picocci
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, Medical School, University of Bari Policlinico. Piazza Giulio Cesare. I-70124 Bari, Italy
| | - Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Italy
| | - Patrizia Corsi
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs, Medical School, University of Bari Policlinico. Piazza Giulio Cesare. I-70124 Bari, Italy
| | - Andrew J W Furley
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2NT, UK
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30
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Lu Z, Reddy MVVVS, Liu J, Kalichava A, Liu J, Zhang L, Chen F, Wang Y, Holthauzen LMF, White MA, Seshadrinathan S, Zhong X, Ren G, Rudenko G. Molecular Architecture of Contactin-associated Protein-like 2 (CNTNAP2) and Its Interaction with Contactin 2 (CNTN2). J Biol Chem 2016; 291:24133-24147. [PMID: 27621318 DOI: 10.1074/jbc.m116.748236] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/02/2016] [Indexed: 11/06/2022] Open
Abstract
Contactin-associated protein-like 2 (CNTNAP2) is a large multidomain neuronal adhesion molecule implicated in a number of neurological disorders, including epilepsy, schizophrenia, autism spectrum disorder, intellectual disability, and language delay. We reveal here by electron microscopy that the architecture of CNTNAP2 is composed of a large, medium, and small lobe that flex with respect to each other. Using epitope labeling and fragments, we assign the F58C, L1, and L2 domains to the large lobe, the FBG and L3 domains to the middle lobe, and the L4 domain to the small lobe of the CNTNAP2 molecular envelope. Our data reveal that CNTNAP2 has a very different architecture compared with neurexin 1α, a fellow member of the neurexin superfamily and a prototype, suggesting that CNTNAP2 uses a different strategy to integrate into the synaptic protein network. We show that the ectodomains of CNTNAP2 and contactin 2 (CNTN2) bind directly and specifically, with low nanomolar affinity. We show further that mutations in CNTNAP2 implicated in autism spectrum disorder are not segregated but are distributed over the whole ectodomain. The molecular shape and dimensions of CNTNAP2 place constraints on how CNTNAP2 integrates in the cleft of axo-glial and neuronal contact sites and how it functions as an organizing and adhesive molecule.
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Affiliation(s)
- Zhuoyang Lu
- From the Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720.,the Center for Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - M V V V Sekhar Reddy
- the Department of Pharmacology and Toxicology.,the Sealy Center for Structural Biology and Molecular Biophysics and
| | - Jianfang Liu
- From the Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Ana Kalichava
- the Department of Pharmacology and Toxicology.,the Sealy Center for Structural Biology and Molecular Biophysics and
| | - Jiankang Liu
- the Center for Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Lei Zhang
- From the Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Fang Chen
- the University of Michigan, Ann Arbor, Michigan 48109
| | - Yun Wang
- the University of Michigan, Ann Arbor, Michigan 48109
| | | | - Mark A White
- the Sealy Center for Structural Biology and Molecular Biophysics and.,the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555, and
| | - Suchithra Seshadrinathan
- the Department of Pharmacology and Toxicology.,the Sealy Center for Structural Biology and Molecular Biophysics and
| | - Xiaoying Zhong
- the Department of Pharmacology and Toxicology.,the Sealy Center for Structural Biology and Molecular Biophysics and
| | - Gang Ren
- From the Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720,
| | - Gabby Rudenko
- the Department of Pharmacology and Toxicology, .,the Sealy Center for Structural Biology and Molecular Biophysics and
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31
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Abstract
Myelinated axons are divided into polarized subdomains including axon initial segments and nodes of Ranvier. These domains initiate and propagate action potentials and regulate the trafficking and localization of somatodendritic and axonal proteins. Formation of axon initial segments and nodes of Ranvier depends on intrinsic (neuronal) and extrinsic (glial) interactions. Several levels of redundancy in both mechanisms and molecules also exist to ensure efficient node formation. Furthermore, the establishment of polarized domains at and near nodes of Ranvier reflects the intrinsic polarity of the myelinating glia responsible for node assembly. Here, we discuss the various polarized domains of myelinated axons, how they are established by both intrinsic and extrinsic interactions, and the polarity of myelinating glia.
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Affiliation(s)
- Daniel R Zollinger
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030;
| | - Kelli L Baalman
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030;
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030;
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32
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Intrathecal gene therapy rescues a model of demyelinating peripheral neuropathy. Proc Natl Acad Sci U S A 2016; 113:E2421-9. [PMID: 27035961 DOI: 10.1073/pnas.1522202113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Inherited demyelinating peripheral neuropathies are progressive incurable diseases without effective treatment. To develop a gene therapy approach targeting myelinating Schwann cells that can be translatable, we delivered a lentiviral vector using a single lumbar intrathecal injection and a myelin-specific promoter. The human gene of interest, GJB1, which is mutated in X-linked Charcot-Marie-Tooth Disease (CMT1X), was delivered intrathecally into adult Gjb1-null mice, a genetically authentic model of CMT1X that develops a demyelinating peripheral neuropathy. We obtained widespread, stable, and cell-specific expression of connexin32 in up to 50% of Schwann cells in multiple lumbar spinal roots and peripheral nerves. Behavioral and electrophysiological analysis revealed significantly improved motor performance, quadriceps muscle contractility, and sciatic nerve conduction velocities. Furthermore, treated mice exhibited reduced numbers of demyelinated and remyelinated fibers and fewer inflammatory cells in lumbar motor roots, as well as in the femoral motor and sciatic nerves. This study demonstrates that a single intrathecal lentiviral gene delivery can lead to Schwann cell-specific expression in spinal roots extending to multiple peripheral nerves. This clinically relevant approach improves the phenotype of an inherited neuropathy mouse model and provides proof of principle for treating inherited demyelinating neuropathies.
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Hivert B, Pinatel D, Labasque M, Tricaud N, Goutebroze L, Faivre-Sarrailh C. Assembly of juxtaparanodes in myelinating DRG culture: Differential clustering of the Kv1/Caspr2 complex and scaffolding protein 4.1B. Glia 2016; 64:840-52. [PMID: 26840208 DOI: 10.1002/glia.22968] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 01/04/2016] [Accepted: 01/06/2016] [Indexed: 11/06/2022]
Abstract
The precise distribution of ion channels at the nodes of Ranvier is essential for the efficient propagation of action potentials along myelinated axons. The voltage-gated potassium channels Kv1.1/1.2 are clustered at the juxtaparanodes in association with the cell adhesion molecules, Caspr2 and TAG-1 and the scaffolding protein 4.1B. In the present study, we set up myelinating cultures of DRG neurons and Schwann cells to look through the formation of juxtaparanodes in vitro. We showed that the Kv1.1/Kv1.2 channels were first enriched at paranodes before being restricted to distal paranodes and juxtaparanodes. In addition, the Kv1 channels displayed an asymmetric expression enriched at the distal juxtaparanodes. Caspr2 was strongly co-localized with Kv1.2 whereas the scaffolding protein 4.1B was preferentially recruited at paranodes while being present at juxtaparanodes too. Kv1.2/Caspr2 but not 4.1B, also transiently accumulated within the nodal region both in myelinated cultures and developing sciatic nerves. Studying cultures and sciatic nerves from 4.1B KO mice, we further showed that 4.1B is required for the proper targeting of Caspr2 early during myelination. Moreover, using adenoviral-mediated expression of Caspr-GFP and photobleaching experiments, we analyzed the stability of paranodal junctions and showed that the lateral stability of paranodal Caspr was not altered in 4.1B KO mice indicating that 4.1B is not required for the assembly and stability of the paranodal junctions. Thus, developing an adapted culture paradigm, we provide new insights into the dynamic and differential distribution of Kv1 channels and associated proteins during myelination.
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Affiliation(s)
- Bruno Hivert
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille-UMR7286, Marseille, France
| | - Delphine Pinatel
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille-UMR7286, Marseille, France
| | - Marilyne Labasque
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille-UMR7286, Marseille, France
| | - Nicolas Tricaud
- INSERM U1051 Institut des Neurosciences de Montpellier, Montpellier, France
| | | | - Catherine Faivre-Sarrailh
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille-UMR7286, Marseille, France
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34
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An L, Zhang T. Comparison Impairments of Spatial Cognition and Hippocampal Synaptic Plasticity Between Prenatal and Postnatal Melamine Exposure in Male Adult Rats. Neurotox Res 2015; 29:218-29. [DOI: 10.1007/s12640-015-9578-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/14/2015] [Accepted: 11/17/2015] [Indexed: 12/12/2022]
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35
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Bastakis GG, Savvaki M, Stamatakis A, Vidaki M, Karagogeos D. Tag1 deficiency results in olfactory dysfunction through impaired migration of mitral cells. Development 2015; 142:4318-28. [PMID: 26525675 DOI: 10.1242/dev.123943] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 10/22/2015] [Indexed: 01/01/2023]
Abstract
The olfactory system provides mammals with the abilities to investigate, communicate and interact with their environment. These functions are achieved through a finely organized circuit starting from the nasal cavity, passing through the olfactory bulb and ending in various cortical areas. We show that the absence of transient axonal glycoprotein-1 (Tag1)/contactin-2 (Cntn2) in mice results in a significant and selective defect in the number of the main projection neurons in the olfactory bulb, namely the mitral cells. A subpopulation of these projection neurons is reduced in Tag1-deficient mice as a result of impaired migration. We demonstrate that the detected alterations in the number of mitral cells are well correlated with diminished odor discrimination ability and social long-term memory formation. Reduced neuronal activation in the olfactory bulb and the corresponding olfactory cortex suggest that Tag1 is crucial for the olfactory circuit formation in mice. Our results underpin the significance of a numerical defect in the mitral cell layer in the processing and integration of odorant information and subsequently in animal behavior.
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Affiliation(s)
- George G Bastakis
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
| | - Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
| | - Antonis Stamatakis
- Laboratory of Biology, Faculty of Nursing, School of Health Sciences, University of Athens, Papadiamantopoulou 123, Athens GR11527, Greece
| | - Marina Vidaki
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
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36
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Pinatel D, Hivert B, Boucraut J, Saint-Martin M, Rogemond V, Zoupi L, Karagogeos D, Honnorat J, Faivre-Sarrailh C. Inhibitory axons are targeted in hippocampal cell culture by anti-Caspr2 autoantibodies associated with limbic encephalitis. Front Cell Neurosci 2015. [PMID: 26217189 PMCID: PMC4496579 DOI: 10.3389/fncel.2015.00265] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Contactin-associated protein-like 2 (Caspr2), also known as CNTNAP2, is a cell adhesion molecule that clusters voltage-gated potassium channels (Kv1.1/1.2) at the juxtaparanodes of myelinated axons and may regulate axonal excitability. As a component of the Kv1 complex, Caspr2 has been identified as a target in neuromyotonia and Morvan syndrome, but also in some cases of autoimmune limbic encephalitis (LE). How anti-Caspr2 autoimmunity is linked with the central neurological symptoms is still elusive. In the present study, using anti-Caspr2 antibodies from seven patients affected by pure LE, we determined that IgGs in the cerebrospinal fluid of four out seven patients were selectively directed against the N-terminal Discoïdin and LamininG1 modules of Caspr2. Using live immunolabeling of cultured hippocampal neurons, we determined that serum IgGs in all patients strongly targeted inhibitory interneurons. Caspr2 was highly detected on GAD65-positive axons that are surrounding the cell bodies and at the VGAT-positive inhibitory presynaptic contacts. Functional assays indicated that LE autoantibodies may induce alteration of Gephyrin clusters at inhibitory synaptic contacts. Next, we generated a Caspr2-Fc chimera to reveal Caspr2 receptors on hippocampal neurons localized at the somato-dendritic compartment and post-synapse. Caspr2-Fc binding was strongly increased on TAG-1-transfected neurons and conversely, Caspr2-Fc did not bind hippocampal neurons from TAG-1-deficient mice. Our data indicate that Caspr2 may participate as a cell recognition molecule in the dynamics of inhibitory networks. This study provides new insight into the potential pathogenic effect of anti-Caspr2 autoantibodies in central hyperexcitability that may be related with perturbation of inhibitory interneuron activity.
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Affiliation(s)
- Delphine Pinatel
- Aix Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, CRN2M-UMR7286, Faculté de Médecine Nord Marseille, France
| | - Bruno Hivert
- Aix Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, CRN2M-UMR7286, Faculté de Médecine Nord Marseille, France
| | - José Boucraut
- Aix Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, CRN2M-UMR7286, Faculté de Médecine Nord Marseille, France ; Laboratoire d'Immunologie et d'Immunopathologie, AP-HM, Hôpital de la Conception Marseille, France
| | - Margaux Saint-Martin
- French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique Bron, France ; INSERM U1028 - CNRS UMR 5292, Lyon Neuroscience Research Center Lyon, France ; Université de Lyon - Université Claude Bernard Lyon 1 Lyon, France
| | - Véronique Rogemond
- French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique Bron, France ; INSERM U1028 - CNRS UMR 5292, Lyon Neuroscience Research Center Lyon, France ; Université de Lyon - Université Claude Bernard Lyon 1 Lyon, France
| | - Lida Zoupi
- Institute of Molecular Biology and Biotechnology - Foundation for Research and Technology, University of Crete Heraklion, Greece
| | - Domna Karagogeos
- Institute of Molecular Biology and Biotechnology - Foundation for Research and Technology, University of Crete Heraklion, Greece
| | - Jérôme Honnorat
- French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique Bron, France ; INSERM U1028 - CNRS UMR 5292, Lyon Neuroscience Research Center Lyon, France ; Université de Lyon - Université Claude Bernard Lyon 1 Lyon, France
| | - Catherine Faivre-Sarrailh
- Aix Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, CRN2M-UMR7286, Faculté de Médecine Nord Marseille, France
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Olsen AL, Lai Y, Dalmau J, Scherer SS, Lancaster E. Caspr2 autoantibodies target multiple epitopes. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2015; 2:e127. [PMID: 26185774 PMCID: PMC4496632 DOI: 10.1212/nxi.0000000000000127] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 05/22/2015] [Indexed: 01/17/2023]
Abstract
Objective: To better understand the mechanisms of autoantibodies to the axonal protein contactin-associated protein-like 2 (Caspr2) by studying their target epitopes. Methods: A plasmid for expressing Caspr2 was modified so that the various extracellular subdomains were deleted individually and in groups. Cultured cells were transfected to express these constructs and assayed by immunofluorescence staining with a commercial Caspr2 antibody and a panel of patient sera known to react with Caspr2. Western blotting was also performed. The role of glycosylation in immunogenicity was tested with tunicamycin and PNGase F treatment. Results: Patient antibodies bound to the extracellular domain of Caspr2. Neither native protein structure nor glycosylation was required for immunoreactivity. Caspr2 constructs with single or multidomain deletions were expressed on the plasma membrane. All deletion constructs were recognized by patients' sera, although reactivity was significantly reduced with deletion of the discoidin-like subdomain and strongly reduced or abolished with larger deletions of multiple N-terminal subdomains. Caspr2 with all subdomains deleted except the discoidin-like domain was still recognized by the antibodies. Conclusion: Caspr2 autoantibodies recognize multiple target epitopes in the extracellular domain of Caspr2, including one in the discoidin-like domain. Reactivity for some epitopes is not dependent on glycosylation or native protein structure.
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Affiliation(s)
- Abby L Olsen
- Department of Neurology (A.L.O., Y.L., J.D., S.S.S., E.L.), The University of Pennsylvania, Philadelphia; and ICREA-IDIBAPS (J.D.), Hospital Unit, University of Barcelona, Spain
| | - Yongjie Lai
- Department of Neurology (A.L.O., Y.L., J.D., S.S.S., E.L.), The University of Pennsylvania, Philadelphia; and ICREA-IDIBAPS (J.D.), Hospital Unit, University of Barcelona, Spain
| | - Josep Dalmau
- Department of Neurology (A.L.O., Y.L., J.D., S.S.S., E.L.), The University of Pennsylvania, Philadelphia; and ICREA-IDIBAPS (J.D.), Hospital Unit, University of Barcelona, Spain
| | - Steven S Scherer
- Department of Neurology (A.L.O., Y.L., J.D., S.S.S., E.L.), The University of Pennsylvania, Philadelphia; and ICREA-IDIBAPS (J.D.), Hospital Unit, University of Barcelona, Spain
| | - Eric Lancaster
- Department of Neurology (A.L.O., Y.L., J.D., S.S.S., E.L.), The University of Pennsylvania, Philadelphia; and ICREA-IDIBAPS (J.D.), Hospital Unit, University of Barcelona, Spain
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Kastriti ME, Sargiannidou I, Kleopa KA, Karagogeos D. Differential modulation of the juxtaparanodal complex in Multiple Sclerosis. Mol Cell Neurosci 2015; 67:93-103. [DOI: 10.1016/j.mcn.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/25/2015] [Accepted: 06/08/2015] [Indexed: 12/23/2022] Open
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Normand EA, Rasband MN. Subcellular patterning: axonal domains with specialized structure and function. Dev Cell 2015; 32:459-68. [PMID: 25710532 DOI: 10.1016/j.devcel.2015.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Myelinated axons are patterned into discrete and often-repeating domains responsible for the efficient and rapid transmission of electrical signals. These domains include nodes of Ranvier and axon initial segments. Disruption of axonal patterning leads to nervous system dysfunction. In this review, we introduce the concept of subcellular patterning as applied to axons and discuss how these patterning events depend on both intrinsic, cytoskeletal mechanisms and extrinsic, myelinating glia-dependent mechanisms.
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Affiliation(s)
- Elizabeth A Normand
- Department of Neuroscience Baylor College of Medicine, Houston, TX 77030, USA
| | - Matthew N Rasband
- Department of Neuroscience Baylor College of Medicine, Houston, TX 77030, USA.
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Schiza N, Sargiannidou I, Kagiava A, Karaiskos C, Nearchou M, Kleopa KA. Transgenic replacement of Cx32 in gap junction-deficient oligodendrocytes rescues the phenotype of a hypomyelinating leukodystrophy model. Hum Mol Genet 2015; 24:2049-64. [PMID: 25524707 DOI: 10.1093/hmg/ddu725] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oligodendrocytes are coupled by gap junctions (GJs) formed mainly by connexin47 (Cx47) and Cx32. Recessive GJC2/Cx47 mutations cause Pelizaeus-Merzbacher-like disease, a hypomyelinating leukodystrophy, while GJB1/Cx32 mutations cause neuropathy and chronic or acute-transient encephalopathy syndromes. Cx32/Cx47 double knockout (Cx32/Cx47dKO) mice develop severe CNS demyelination beginning at 1 month of age leading to death within weeks, offering a relevant model to study disease mechanisms. In order to clarify whether the loss of oligodendrocyte connexins has cell autonomous effects, we generated transgenic mice expressing the wild-type human Cx32 under the control of the mouse proteolipid protein promoter, obtaining exogenous hCx32 expression in oligodendrocytes. By crossing these mice with Cx32KO mice, we obtained expression of hCx32 on Cx32KO background. Immunohistochemical and immunoblot analysis confirmed strong CNS expression of hCx32 specifically in oligodendrocytes and correct localization forming GJs at cell bodies and along the myelin sheath. TG(+)Cx32/Cx47dKO mice generated by further crossing with Cx47KO mice showed that transgenic expression of hCx32 rescued the severe early phenotype of CNS demyelination in Cx32/Cx47dKO mice, resulting in marked improvement of behavioral abnormalities at 1 month of age, and preventing the early mortality. Furthermore, TG(+)Cx32/Cx47dKO mice showed significant improvement of myelination compared with Cx32/Cx47dKO CNS at 1 month of age, while the inflammatory and astrogliotic changes were fully reversed. Our study confirms that loss of oligodendrocyte GJs has cell autonomous effects and that re-establishment of GJ connectivity by replacement of least one GJ protein provides correction of the leukodystrophy phenotype.
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Affiliation(s)
| | | | | | | | - Marianna Nearchou
- Department of Molecular Pathology and Electron Microscopy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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41
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Prenatal melamine exposure induces impairments of spatial cognition and hippocampal synaptic plasticity in male adolescent rats. Reprod Toxicol 2014; 49:78-85. [DOI: 10.1016/j.reprotox.2014.07.081] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/27/2014] [Accepted: 07/30/2014] [Indexed: 11/19/2022]
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New insights into the roles of the contactin cell adhesion molecules in neural development. ADVANCES IN NEUROBIOLOGY 2014; 8:165-94. [PMID: 25300137 DOI: 10.1007/978-1-4614-8090-7_8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In vertebrates, the contactin (CNTN) family of neural cell recognition molecules includes six related cell adhesion molecules that play non-overlapping roles in the formation and maintenance of the nervous system. CNTN1 and CNTN2 are the prototypical members of the family and have been involved, through cis- and trans-interactions with distinct cell adhesion molecules, in neural cell migration, axon guidance, and the organization of myelin subdomains. In contrast, the roles of CNTN3-6 are less well characterized although the generation of null mice and the recent identification of a common extracellular binding partner have considerably advanced our grasp of their physiological roles in particular as they relate to the wiring of sensory tissues. In this review, we aim to present a summary of our current understanding of CNTN functions and give an overview of the challenges that lie ahead in understanding the roles these proteins play in nervous system development and maintenance.
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43
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Faivre-Sarrailh C, Devaux JJ. Neuro-glial interactions at the nodes of Ranvier: implication in health and diseases. Front Cell Neurosci 2013; 7:196. [PMID: 24194699 PMCID: PMC3810605 DOI: 10.3389/fncel.2013.00196] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/08/2013] [Indexed: 01/06/2023] Open
Abstract
Specific cell adhesion molecules (CAMs) are dedicated to the formation of axo-glial contacts at the nodes of Ranvier of myelinated axons. They play a central role in the organization and maintenance of the axonal domains: the node, paranode, and juxtaparanode. In particular, CAMs are essential for the accumulation of voltage-gated sodium channels at the nodal gap that ensures the rapid and saltatory propagation of the action potentials (APs). The mechanisms regulating node formation are distinct in the central and peripheral nervous systems, and recent studies have highlighted the relative contribution of paranodal junctions and nodal extracellular matrix. In addition, CAMs at the juxtaparanodal domains mediate the clustering of voltage-gated potassium channels which regulate the axonal excitability. In several human pathologies, the axo-glial contacts are altered leading to disruption of the nodes of Ranvier or mis-localization of the ion channels along the axons. Node alterations and the failure of APs to propagate correctly from nodes to nodes along the axons both contribute to the disabilities in demyelinating diseases. This article reviews the mechanisms regulating the association of the axo-glial complexes and the role of CAMs in inherited and acquired neurological diseases.
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Puzzo D, Bizzoca A, Privitera L, Furnari D, Giunta S, Girolamo F, Pinto M, Gennarini G, Palmeri A. F3/Contactin promotes hippocampal neurogenesis, synaptic plasticity, and memory in adult mice. Hippocampus 2013; 23:1367-82. [PMID: 23939883 DOI: 10.1002/hipo.22186] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 07/23/2013] [Accepted: 08/02/2013] [Indexed: 12/18/2022]
Abstract
F3/contactin, a cell-adhesion molecule belonging to the immunoglobulin supergene family, is involved in several aspects of neural development including synapse building, maintenance and functioning. Here, we examine F3/contactin function in adult hippocampal neurogenesis, synaptic plasticity, and memory, using as a model TAG/F3 transgenic mice, where F3/contactin overexpression was induced under control of regulatory sequences from the human TAG-1 (TAX-1) gene. Transgenic mice aged 5 (M5) and 12 (M12) months exhibited an increase in hippocampal size, which correlated with positive effects on precursor proliferation and NeuN expression, these data suggesting a possible role for F3/contactin in promoting adult hippocampal neurogenesis. On the functional level, TAG/F3 mice exhibited increased CA1 long-term potentiation and improved spatial and object recognition memory, notably at 12 months of age. Interestingly, these mice showed an increased expression of the phosphorylated transcription factor CREB, which may represent the main molecular correlate of the observed morphological and functional effects. Altogether, these findings indicate for the first time that F3/contactin plays a role in promoting adult hippocampal neurogenesis and that this effect correlates with improved synaptic function and memory.
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Affiliation(s)
- Daniela Puzzo
- Section of Physiology, Department of Bio-Medical Sciences, University of Catania, Catania, Italy
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45
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Zoupi L, Markoullis K, Kleopa KA, Karagogeos D. Alterations of juxtaparanodal domains in two rodent models of CNS demyelination. Glia 2013; 61:1236-49. [DOI: 10.1002/glia.22511] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/20/2013] [Indexed: 01/15/2023]
Affiliation(s)
| | - Kyriaki Markoullis
- Neuroscience Laboratory and Neurology Clinics; The Cyprus Institute of Neurology and Genetics (CING); P.O. Box 23462, 1683 Nicosia; Cyprus
| | - Kleopas A. Kleopa
- Neuroscience Laboratory and Neurology Clinics; The Cyprus Institute of Neurology and Genetics (CING); P.O. Box 23462, 1683 Nicosia; Cyprus
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Gold M, Pul R, Bach JP, Stangel M, Dodel R. Pathogenic and physiological autoantibodies in the central nervous system. Immunol Rev 2012; 248:68-86. [PMID: 22725955 DOI: 10.1111/j.1600-065x.2012.01128.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In this article, we review the current knowledge on pathological and physiological autoantibodies directed toward structures in the central nervous system (CNS) with an emphasis on their regulation and origin. Pathological autoantibodies in the CNS that are associated with autoimmunity often lead to severe neurological deficits via inflammatory processes such as encephalitis. In some instances, however, autoantibodies function as a marker for diagnostic purposes without contributing to the pathological process and/or disease progression. The existence of naturally occurring physiological autoantibodies has been known for a long time, and their role in maintaining homeostasis is well established. Within the brain, naturally occurring autoantibodies targeting aggregated proteins have been detected and might be promising candidates for new therapeutic approaches for neurodegenerative disorders. Further evidence has demonstrated the existence of naturally occurring antibodies targeting antigens on neurons and oligodendrocytes that promote axonal outgrowth and remyelination. The numerous actions of physiological autoantibodies as well as their regulation and origin are summarized in this review.
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Affiliation(s)
- Maike Gold
- Department of Neurology, Philipps-University Marburg, Marburg, Germany
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Azizi G, Mirshafiey A. The potential role of proinflammatory and antiinflammatory cytokines in Alzheimer disease pathogenesis. Immunopharmacol Immunotoxicol 2012; 34:881-95. [DOI: 10.3109/08923973.2012.705292] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Lin JF, Pan HC, Ma LP, Shen YQ, Schachner M. The cell neural adhesion molecule contactin-2 (TAG-1) is beneficial for functional recovery after spinal cord injury in adult zebrafish. PLoS One 2012; 7:e52376. [PMID: 23285014 PMCID: PMC3528781 DOI: 10.1371/journal.pone.0052376] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 11/15/2012] [Indexed: 02/05/2023] Open
Abstract
The cell neural adhesion molecule contactin-2 plays a key role in axon extension and guidance, fasciculation, and myelination during development. We thus asked, whether contactin-2 is also important in nervous system regeneration after trauma. In this study, we used an adult zebrafish spinal cord transection model to test the functions of contactin-2 in spinal cord regeneration. The expression patterns of contactin-2 at different time points after spinal cord injury were studied at the mRNA level by qPCR and in situ hybridization, and contactin-2 protein levels and immunohistological localization were detected by Western blot and immunofluorescence analyses, respectively. Contactin-2 mRNA and protein levels were increased along the central canal at 6 days and 11 days after spinal cord injury, suggesting a requirement for contactin-2 in spinal cord regeneration. Co-localization of contactin-2 and islet-1 (a motoneuron marker) was observed in spinal cords before and after injury. To further explore the functions of contactin-2 in regeneration, an anti-sense morpholino was used to knock down the expression of contactin-2 protein by application at the time of injury. Motion analysis showed that inhibition of contactin-2 retarded the recovery of swimming functions when compared to standard control morpholino. Anterograde and retrograde tracing at 6 weeks after injury showed that knock down of contactin-2 inhibited axonal regrowth from NMLF neurons beyond lesion site. The combined observations indicate that contactin-2 contributes to locomotor recovery and successful regrowth of axons after spinal cord injury in adult zebrafish.
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Affiliation(s)
- Jin-Fei Lin
- Center for Neuroscience, Shantou University Medical College, Shantou, People’s Republic of China
| | - Hong-Chao Pan
- Center for Neuroscience, Shantou University Medical College, Shantou, People’s Republic of China
| | - Li-Ping Ma
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
| | - Yan-Qin Shen
- Center for Neuroscience, Shantou University Medical College, Shantou, People’s Republic of China
- * E-mail: (YQS); (MS)
| | - Melitta Schachner
- Center for Neuroscience, Shantou University Medical College, Shantou, People’s Republic of China
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail: (YQS); (MS)
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Duflocq A, Chareyre F, Giovannini M, Couraud F, Davenne M. Characterization of the axon initial segment (AIS) of motor neurons and identification of a para-AIS and a juxtapara-AIS, organized by protein 4.1B. BMC Biol 2011; 9:66. [PMID: 21958379 PMCID: PMC3198992 DOI: 10.1186/1741-7007-9-66] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 09/29/2011] [Indexed: 11/26/2022] Open
Abstract
Background The axon initial segment (AIS) plays a crucial role: it is the site where neurons initiate their electrical outputs. Its composition in terms of voltage-gated sodium (Nav) and voltage-gated potassium (Kv) channels, as well as its length and localization determine the neuron's spiking properties. Some neurons are able to modulate their AIS length or distance from the soma in order to adapt their excitability properties to their activity level. It is therefore crucial to characterize all these parameters and determine where the myelin sheath begins in order to assess a neuron's excitability properties and ability to display such plasticity mechanisms. If the myelin sheath starts immediately after the AIS, another question then arises as to how would the axon be organized at its first myelin attachment site; since AISs are different from nodes of Ranvier, would this particular axonal region resemble a hemi-node of Ranvier? Results We have characterized the AIS of mouse somatic motor neurons. In addition to constant determinants of excitability properties, we found heterogeneities, in terms of AIS localization and Nav composition. We also identified in all α motor neurons a hemi-node-type organization, with a contactin-associated protein (Caspr)+ paranode-type, as well as a Caspr2+ and Kv1+ juxtaparanode-type compartment, referred to as a para-AIS and a juxtapara (JXP)-AIS, adjacent to the AIS, where the myelin sheath begins. We found that Kv1 channels appear in the AIS, para-AIS and JXP-AIS concomitantly with myelination and are progressively excluded from the para-AIS. Their expression in the AIS and JXP-AIS is independent from transient axonal glycoprotein-1 (TAG-1)/Caspr2, in contrast to juxtaparanodes, and independent from PSD-93. Data from mice lacking the cytoskeletal linker protein 4.1B show that this protein is necessary to form the Caspr+ para-AIS barrier, ensuring the compartmentalization of Kv1 channels and the segregation of the AIS, para-AIS and JXP-AIS. Conclusions α Motor neurons have heterogeneous AISs, which underlie different spiking properties. However, they all have a para-AIS and a JXP-AIS contiguous to their AIS, where the myelin sheath begins, which might limit some AIS plasticity. Protein 4.1B plays a key role in ensuring the proper molecular compartmentalization of this hemi-node-type region.
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Zoupi L, Savvaki M, Karagogeos D. Axons and myelinating glia: An intimate contact. IUBMB Life 2011; 63:730-5. [PMID: 21793162 DOI: 10.1002/iub.513] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 04/18/2011] [Indexed: 01/06/2023]
Abstract
The coordination of the vertebrate nervous system requires high velocity signal transmission between different brain areas. High speed nerve conduction is achieved in the myelinated fibers of both the central and the peripheral nervous system where the myelin sheath acts as an insulator of the axon. The interactions between the glial cell and the adjacent axon, namely axo-glial interactions, segregate the fiber in distinct molecular and functional domains that ensure the rapid propagation of action potentials. These domains are the node of Ranvier, the paranode, the juxtaparanode and the internode and are characterized by multiprotein complexes between voltage-gated ion channels, cell adhesion molecules, members of the Neurexin family and cytoskeletal proteins. In the present review, we outline recent evidence on the key players of axo-glial interactions, depicting their importance in myelinated fiber physiology and disease.
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Affiliation(s)
- Lida Zoupi
- Department of Basic Science, Faculty of Medicine, University of Crete, Institute of Molecular Biology & Biotechnology-FoRTH, Heraklion, Greece
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