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Kozar-Gillan N, Velichkova A, Kanatouris G, Eshed-Eisenbach Y, Steel G, Jaegle M, Aunin E, Peles E, Torsney C, Meijer DN. LGI3/2-ADAM23 interactions cluster Kv1 channels in myelinated axons to regulate refractory period. J Cell Biol 2023; 222:e202211031. [PMID: 36828548 PMCID: PMC9997507 DOI: 10.1083/jcb.202211031] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/18/2022] [Accepted: 01/17/2023] [Indexed: 02/26/2023] Open
Abstract
Along myelinated axons, Shaker-type potassium channels (Kv1) accumulate at high density in the juxtaparanodal region, directly adjacent to the paranodal axon-glia junctions that flank the nodes of Ranvier. However, the mechanisms that control the clustering of Kv1 channels, as well as their function at this site, are still poorly understood. Here we demonstrate that axonal ADAM23 is essential for both the accumulation and stability of juxtaparanodal Kv1 complexes. The function of ADAM23 is critically dependent on its interaction with its extracellular ligands LGI2 and LGI3. Furthermore, we demonstrate that juxtaparanodal Kv1 complexes affect the refractory period, thus enabling high-frequency burst firing of action potentials. Our findings not only reveal a previously unknown molecular pathway that regulates Kv1 channel clustering, but they also demonstrate that the juxtaparanodal Kv1 channels that are concealed below the myelin sheath, play a significant role in modifying axonal physiology.
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Affiliation(s)
- Nina Kozar-Gillan
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
| | | | - George Kanatouris
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology and Molecular Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Gavin Steel
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
| | | | - Eerik Aunin
- Biomedical Sciences, ErasmusMC, Rotterdam, Netherlands
| | - Elior Peles
- Department of Molecular Cell Biology and Molecular Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Carole Torsney
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh. UK
| | - Dies N. Meijer
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK
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2
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Ogawa Y, Lim BC, George S, Oses-Prieto JA, Rasband JM, Eshed-Eisenbach Y, Nair S, Boato F, Peles E, Burlingame AL, Van Aelst L, Rasband MN. Antibody-directed extracellular proximity biotinylation reveals Contactin-1 regulates axo-axonic innervation of axon initial segments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531378. [PMID: 36945454 PMCID: PMC10028829 DOI: 10.1101/2023.03.06.531378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Axon initial segment (AIS) cell surface proteins mediate key biological processes in neurons including action potential initiation and axo-axonic synapse formation. However, few AIS cell surface proteins have been identified. Here, we used antibody-directed proximity biotinylation to define the cell surface proteins in close proximity to the AIS cell adhesion molecule Neurofascin. To determine the distributions of the identified proteins, we used CRISPR-mediated genome editing for insertion of epitope tags in the endogenous proteins. We found Contactin-1 (Cntn1) among the previously unknown AIS proteins we identified. Cntn1 is enriched at the AIS through interactions with Neurofascin and NrCAM. We further show that Cntn1 contributes to assembly of the AIS-extracellular matrix, and is required for AIS axo-axonic innervation by inhibitory basket cells in the cerebellum and inhibitory chandelier cells in the cortex.
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Affiliation(s)
- Yuki Ogawa
- Baylor College of Medicine, Department of Neuroscience, Houston, TX, USA
| | - Brian C. Lim
- Baylor College of Medicine, Department of Neuroscience, Houston, TX, USA
| | - Shanu George
- Cold Spring Harbor Laboratory, Division of Neuroscience, Cold Spring Harbor, NY, USA
| | - Juan A. Oses-Prieto
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA, USA
| | - Joshua M. Rasband
- Baylor College of Medicine, Department of Neuroscience, Houston, TX, USA
| | - Yael Eshed-Eisenbach
- Weizmann Institute of Science, Department of Molecular Cell Biology, Rehovot, Israel
| | - Supna Nair
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA, USA
| | - Francesco Boato
- Cold Spring Harbor Laboratory, Division of Neuroscience, Cold Spring Harbor, NY, USA
| | - Elior Peles
- Weizmann Institute of Science, Department of Molecular Cell Biology, Rehovot, Israel
| | - Alma L. Burlingame
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA, USA
| | - Linda Van Aelst
- Cold Spring Harbor Laboratory, Division of Neuroscience, Cold Spring Harbor, NY, USA
| | - Matthew N. Rasband
- Baylor College of Medicine, Department of Neuroscience, Houston, TX, USA
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3
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Liu Y, Shuai K, Sun Y, Zhu L, Wu XM. Advances in the study of axon-associated vesicles. Front Mol Neurosci 2022; 15:1045778. [PMID: 36545123 PMCID: PMC9760877 DOI: 10.3389/fnmol.2022.1045778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/17/2022] [Indexed: 12/12/2022] Open
Abstract
The central nervous system is the most important and difficult to study system in the human body and is known for its complex functions, components, and mechanisms. Neurons are the basic cellular units realizing neural functions. In neurons, vesicles are one of the critical pathways for intracellular material transport, linking information exchanges inside and outside cells. The axon is a vital part of neuron since electrical and molecular signals must be conducted through axons. Here, we describe and explore the formation, trafficking, and sorting of cellular vesicles within axons, as well as related-diseases and practical implications. Furthermore, with deepening of understanding and the development of new approaches, accumulating evidence proves that besides signal transmission between synapses, the material exchange and vesicular transmission between axons and extracellular environment are involved in physiological processes, and consequently to neural pathology. Recent studies have also paid attention to axonal vesicles and their physiological roles and pathological effects on axons themselves. Therefore, this review mainly focuses on these two key nodes to explain the role of intracellular vesicles and extracellular vesicles migrated from cells on axons and neurons, providing innovative strategy for future researches.
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Affiliation(s)
- Yanling Liu
- Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Ke Shuai
- Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Yiyan Sun
- Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Li Zhu
- Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| | - Xiao-Mei Wu
- Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China,*Correspondence: Xiao-Mei Wu,
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4
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Dziadkowiak E, Nowakowska-Kotas M, Budrewicz S, Koszewicz M. Pathology of Initial Axon Segments in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Related Disorders. Int J Mol Sci 2022; 23:13621. [PMID: 36362407 PMCID: PMC9658771 DOI: 10.3390/ijms232113621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 07/30/2023] Open
Abstract
The diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is based on a combination of clinical, electrodiagnostic and laboratory features. The different entities of the disease include chronic immune sensory polyradiculopathy (CISP) and autoimmune nodopathies. It is debatable whether CIDP occurring in the course of other conditions, i.e., monoclonal IgG or IgA gammopathy, should be treated as a separate disease entity from idiopathic CIDP. This study aims to evaluate the molecular differences of the nodes of Ranvier and the initial axon segment (AIS) and juxtaparanode region (JXP) as the potential cause of phenotypic variation of CIDP while also seeking new pathomechanisms since JXP is sequestered behind the paranode and autoantibodies may not access the site easily. The authors initially present the structure of the different parts of the neuron and its functional significance, then discuss the problem of whether damage to the juxtaparanodal region, Schwann cells and axons could cause CIDP or if these damages should be separated as separate disease entities. In particular, AIS's importance for modulating neural excitability and carrying out transport along the axon is highlighted. The disclosure of specific pathomechanisms, including novel target antigens, in the heterogeneous CIDP syndrome is important for diagnosing and treating these patients.
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5
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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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6
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Lipkin AM, Cunniff MM, Spratt PWE, Lemke SM, Bender KJ. Functional Microstructure of Ca V-Mediated Calcium Signaling in the Axon Initial Segment. J Neurosci 2021; 41:3764-3776. [PMID: 33731449 PMCID: PMC8084313 DOI: 10.1523/jneurosci.2843-20.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/15/2021] [Accepted: 03/09/2021] [Indexed: 01/12/2023] Open
Abstract
The axon initial segment (AIS) is a specialized neuronal compartment in which synaptic input is converted into action potential (AP) output. This process is supported by a diverse complement of sodium, potassium, and calcium channels (CaV). Different classes of sodium and potassium channels are scaffolded at specific sites within the AIS, conferring unique functions, but how calcium channels are functionally distributed within the AIS is unclear. Here, we use conventional two-photon laser scanning and diffraction-limited, high-speed spot two-photon imaging to resolve AP-evoked calcium dynamics in the AIS with high spatiotemporal resolution. In mouse layer 5 prefrontal pyramidal neurons, calcium influx was mediated by a mix of CaV2 and CaV3 channels that differentially localized to discrete regions. CaV3 functionally localized to produce nanodomain hotspots of calcium influx that coupled to ryanodine-sensitive stores, whereas CaV2 localized to non-hotspot regions. Thus, different pools of CaVs appear to play distinct roles in AIS function.SIGNIFICANCE STATEMENT The axon initial segment (AIS) is the site where synaptic input is transformed into action potential (AP) output. It achieves this function through a diverse complement of sodium, potassium, and calcium channels (CaV). While the localization and function of sodium channels and potassium channels at the AIS is well described, less is known about the functional distribution of CaVs. We used high-speed two-photon imaging to understand activity-dependent calcium dynamics in the AIS of mouse neocortical pyramidal neurons. Surprisingly, we found that calcium influx occurred in two distinct domains: CaV3 generates hotspot regions of calcium influx coupled to calcium stores, whereas CaV2 channels underlie diffuse calcium influx between hotspots. Therefore, different CaV classes localize to distinct AIS subdomains, possibly regulating distinct cellular processes.
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Affiliation(s)
- Anna M Lipkin
- Neuroscience Graduate Program, University of California, San Francisco, California 94158
| | - Margaret M Cunniff
- Neuroscience Graduate Program, University of California, San Francisco, California 94158
| | - Perry W E Spratt
- Neuroscience Graduate Program, University of California, San Francisco, California 94158
| | - Stefan M Lemke
- Neuroscience Graduate Program, University of California, San Francisco, California 94158
| | - Kevin J Bender
- Neuroscience Graduate Program, University of California, San Francisco, California 94158
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, California 94158
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7
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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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8
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Chytła A, Gajdzik-Nowak W, Olszewska P, Biernatowska A, Sikorski AF, Czogalla A. Not Just Another Scaffolding Protein Family: The Multifaceted MPPs. Molecules 2020; 25:molecules25214954. [PMID: 33114686 PMCID: PMC7662862 DOI: 10.3390/molecules25214954] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 01/03/2023] Open
Abstract
Membrane palmitoylated proteins (MPPs) are a subfamily of a larger group of multidomain proteins, namely, membrane-associated guanylate kinases (MAGUKs). The ubiquitous expression and multidomain structure of MPPs provide the ability to form diverse protein complexes at the cell membranes, which are involved in a wide range of cellular processes, including establishing the proper cell structure, polarity and cell adhesion. The formation of MPP-dependent complexes in various cell types seems to be based on similar principles, but involves members of different protein groups, such as 4.1-ezrin-radixin-moesin (FERM) domain-containing proteins, polarity proteins or other MAGUKs, showing their multifaceted nature. In this review, we discuss the function of the MPP family in the formation of multiple protein complexes. Notably, we depict their significant role for cell physiology, as the loss of interactions between proteins involved in the complex has a variety of negative consequences. Moreover, based on recent studies concerning the mechanism of membrane raft formation, we shed new light on a possible role played by MPPs in lateral membrane organization.
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Affiliation(s)
- Agnieszka Chytła
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Weronika Gajdzik-Nowak
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Paulina Olszewska
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Agnieszka Biernatowska
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Aleksander F. Sikorski
- Research and Development Center, Regional Specialist Hospital, Kamieńskiego 73a, 51-154 Wroclaw, Poland;
| | - Aleksander Czogalla
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
- Correspondence: ; Tel.: +48-71375-6356
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9
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Torii T, Ogawa Y, Liu CH, Ho TSY, Hamdan H, Wang CC, Oses-Prieto JA, Burlingame AL, Rasband MN. NuMA1 promotes axon initial segment assembly through inhibition of endocytosis. J Cell Biol 2020; 219:jcb.201907048. [PMID: 31727776 PMCID: PMC7041696 DOI: 10.1083/jcb.201907048] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 11/22/2022] Open
Abstract
Axon initial segments (AISs) initiate action potentials and regulate the trafficking of vesicles between somatodendritic and axonal compartments. Torii et al. show that NuMA1 is transiently located at the AIS and promotes rapid AIS assembly by inhibiting the endocytosis of neurofascin-186. Axon initial segments (AISs) initiate action potentials and regulate the trafficking of vesicles between somatodendritic and axonal compartments. However, the mechanisms controlling AIS assembly remain poorly defined. We performed differential proteomics and found nuclear mitotic apparatus protein 1 (NuMA1) is downregulated in AIS-deficient neonatal mouse brains and neurons. NuMA1 is transiently located at the AIS during development where it interacts with the scaffolding protein 4.1B and the dynein regulator lissencephaly 1 (Lis1). Silencing NuMA1 or protein 4.1B by shRNA disrupts AIS assembly, but not maintenance. Silencing Lis1 or overexpressing NuMA1 during AIS assembly increased the density of AIS proteins, including ankyrinG and neurofascin-186 (NF186). NuMA1 inhibits the endocytosis of AIS NF186 by impeding Lis1’s interaction with doublecortin, a potent facilitator of NF186 endocytosis. Our results indicate the transient expression and AIS localization of NuMA1 stabilizes the developing AIS by inhibiting endocytosis and removal of AIS proteins.
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Affiliation(s)
- Tomohiro Torii
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Yuki Ogawa
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Cheng-Hsin Liu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Hamdan Hamdan
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Chih-Chuan Wang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA
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10
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Colasante G, Qiu Y, Massimino L, Di Berardino C, Cornford JH, Snowball A, Weston M, Jones SP, Giannelli S, Lieb A, Schorge S, Kullmann DM, Broccoli V, Lignani G. In vivo CRISPRa decreases seizures and rescues cognitive deficits in a rodent model of epilepsy. Brain 2020; 143:891-905. [PMID: 32129831 PMCID: PMC7089667 DOI: 10.1093/brain/awaa045] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/31/2019] [Accepted: 01/14/2020] [Indexed: 01/20/2023] Open
Abstract
Epilepsy is a major health burden, calling for new mechanistic insights and therapies. CRISPR-mediated gene editing shows promise to cure genetic pathologies, although hitherto it has mostly been applied ex vivo. Its translational potential for treating non-genetic pathologies is still unexplored. Furthermore, neurological diseases represent an important challenge for the application of CRISPR, because of the need in many cases to manipulate gene function of neurons in situ. A variant of CRISPR, CRISPRa, offers the possibility to modulate the expression of endogenous genes by directly targeting their promoters. We asked if this strategy can effectively treat acquired focal epilepsy, focusing on ion channels because their manipulation is known be effective in changing network hyperactivity and hypersynchronziation. We applied a doxycycline-inducible CRISPRa technology to increase the expression of the potassium channel gene Kcna1 (encoding Kv1.1) in mouse hippocampal excitatory neurons. CRISPRa-mediated Kv1.1 upregulation led to a substantial decrease in neuronal excitability. Continuous video-EEG telemetry showed that AAV9-mediated delivery of CRISPRa, upon doxycycline administration, decreased spontaneous generalized tonic-clonic seizures in a model of temporal lobe epilepsy, and rescued cognitive impairment and transcriptomic alterations associated with chronic epilepsy. The focal treatment minimizes concerns about off-target effects in other organs and brain areas. This study provides the proof-of-principle for a translational CRISPR-based approach to treat neurological diseases characterized by abnormal circuit excitability.
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Affiliation(s)
- Gaia Colasante
- San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milan, Italy
| | - Yichen Qiu
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Luca Massimino
- San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milan, Italy
| | | | - Jonathan H Cornford
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Albert Snowball
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Mikail Weston
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Steffan P Jones
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Serena Giannelli
- San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milan, Italy
| | - Andreas Lieb
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Vania Broccoli
- San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milan, Italy.,CNR Institute of Neuroscience, Via Vanvitelli 32, 20129, Milan, Italy
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
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11
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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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12
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Kirschstein T, Sadkiewicz E, Hund-Göschel G, Becker J, Guli X, Müller S, Rohde M, Hübner DC, Brehme H, Kolbaske S, Porath K, Sellmann T, Großmann A, Wittstock M, Syrbe S, Storch A, Köhling R. Stereotactically Injected Kv1.2 and CASPR2 Antisera Cause Differential Effects on CA1 Synaptic and Cellular Excitability, but Both Enhance the Vulnerability to Pro-epileptic Conditions. Front Synaptic Neurosci 2020; 12:13. [PMID: 32269520 PMCID: PMC7110982 DOI: 10.3389/fnsyn.2020.00013] [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: 10/02/2019] [Accepted: 03/06/2020] [Indexed: 12/12/2022] Open
Abstract
PURPOSE We present a case of voltage-gated potassium channel (VGKC) complex antibody-positive limbic encephalitis (LE) harboring autoantibodies against Kv1.2. Since the patient responded well to immunotherapy, the autoantibodies were regarded as pathogenic. We aimed to characterize the pathophysiological role of this antibody in comparison to an antibody against the VGKC-associated protein contactin-associated protein-2 (CASPR2). METHODS Stereotactic injection of patient sera (anti-Kv1.2-associated LE or anti-CASPR2 encephalopathy) and a control subject was performed into the hippocampus of the anesthetized rat in vivo, and hippocampal slices were prepared for electrophysiological purposes. Using extra- and intracellular techniques, synaptic transmission, long-term potentiation (LTP) and vulnerability to pro-epileptic conditions were analyzed. RESULTS We observed that the slope of the field excitatory postsynaptic potential (fEPSP) was significantly increased at Schaffer collateral-CA1 synapses in anti-Kv1.2-treated and anti-CASPR2-treated rats, but not at medial perforant path-dentate gyrus synapses. The increase of the fEPSP slope in CA1 was accompanied by a decrease of the paired-pulse ratio in anti-Kv1.2, but not in anti-CASPR2 tissue, indicating presynaptic site of anti-Kv1.2. In addition, anti-Kv1.2 tissue showed enhanced LTP in CA1, but dentate gyrus LTP remained unaltered. Importantly, LTP in slices from anti-CASPR2-treated animals did not differ from control values. Intracellular recordings from CA1 neurons revealed that the resting membrane potential and a single action potential were not different between anti-Kv1.2 and control tissue. However, when the depolarization was prolonged, the number of action potentials elicited was reduced in anti-Kv1.2-treated tissue compared to both control and anti-CASPR2 tissue. In contrast, polyspike discharges induced by removal of Mg2+ occurred earlier and more frequently in both patient sera compared to control. CONCLUSION Patient serum containing anti-Kv1.2 facilitates presynaptic transmitter release as well as postsynaptic depolarization at the Schaffer-collateral-CA1 synapse, but not in the dentate gyrus. As a consequence, both synaptic transmission and LTP in CA1 are facilitated and action potential firing is altered. In contrast, anti-CASPR2 leads to increased postsynaptic potentials, but without changing LTP or firing properties suggesting that anti-Kv1.2 and anti-CASPR2 differ in their cellular effects. Both patient sera alter susceptibility to epileptic conditions, but presumably by different mechanisms.
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Affiliation(s)
- Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
- Department of Neurology, University of Rostock, Rostock, Germany
- Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
| | - Erika Sadkiewicz
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Gerda Hund-Göschel
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Juliane Becker
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Xiati Guli
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Steffen Müller
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Marco Rohde
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | | | - Hannes Brehme
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Stephan Kolbaske
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Katrin Porath
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Tina Sellmann
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Annette Großmann
- Institute of Diagnostic and Intervention Radiology, University of Rostock, Rostock, Germany
| | | | - Steffen Syrbe
- Clinik for Pediatric and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany
| | - Alexander Storch
- Department of Neurology, University of Rostock, Rostock, Germany
- Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
- Center of Transdisciplinary Neurosciences Rostock, University of Rostock, Rostock, Germany
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13
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Gao R, Pratt CP, Yoon S, Martin-de-Saavedra MD, Forrest MP, Penzes P. CNTNAP2 is targeted to endosomes by the polarity protein PAR3. Eur J Neurosci 2019; 51:1074-1086. [PMID: 31730244 DOI: 10.1111/ejn.14620] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/24/2019] [Accepted: 10/17/2019] [Indexed: 01/01/2023]
Abstract
A decade of genetic studies has established contactin-associated protein-like 2 (CNTNAP2) as a prominent susceptibility gene associated with multiple neurodevelopmental disorders. The development and characterization of Cntnap2 knockout models in multiple species have bolstered this claim by establishing clear connections with certain endophenotypes. Despite these remarkable in vivo findings, CNTNAP2's molecular functions are relatively unexplored, highlighting the need to identify novel protein partners. Here, we characterized an interaction between CNTNAP2 and partitioning-defective 3 (PAR3)-a polarity molecule isolated in a yeast two-hybrid screen with CNTNAP2's C-terminus. We provide evidence that the two proteins interact via PDZ domain-mediated binding, that CNTNAP2+ /PAR3+ complexes are largely associated with clathrin-coated endocytic vesicles in heterologous cells and that PAR3 causes an enlargement of CNTNAP2 puncta size. Live imaging and fluorescence recovery after photobleaching (FRAP) reveals that PAR3 limits the mobility of CNTNAP2. Finally, overexpression of PAR3 but not a PAR3 mutant lacking all PDZ domains (PAR3∆PDZall) can cluster endogenous CNTNAP2 in primary neurons. Collectively, we conclude that PAR3 regulates CNTNAP2 spatial localization.
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Affiliation(s)
- Ruoqi Gao
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Christopher P Pratt
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Sehyoun Yoon
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | - Marc P Forrest
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Northwestern University, Center for Autism and Neurodevelopment, Chicago, IL, USA
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14
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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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15
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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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16
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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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17
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Hivert B, Marien L, Agbam KN, Faivre-Sarrailh C. ADAM22 and ADAM23 modulate the targeting of the Kv1 channel-associated protein LGI1 to the axon initial segment. J Cell Sci 2018; 132:jcs.219774. [DOI: 10.1242/jcs.219774] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 12/19/2018] [Indexed: 01/30/2023] Open
Abstract
The distribution of voltage-gated potassium channels Kv1 at the axon initial segment (AIS) influences neuronal intrinsic excitability. Kv1.1/1.2 subunits are associated with cell adhesion molecules (CAMs), including Caspr2 and LGI1 that are implicated in autoimmune and genetic neurological diseases with seizures. In particular, mutations in the LGI1 gene cause autosomal dominant lateral temporal lobe epilepsy (ADLTE). Here, using rat hippocampal neurons in culture, we showed that LGI1 is recruited at the AIS and colocalized with ADAM22 and Kv1 channels. Strikingly, the missense mutations S473L and R474Q of LGI1 identified in ADLTE prevent its association with ADAM22 and enrichment at the AIS. Moreover, we observed that ADAM22 or ADAM23 modulates the trafficking of LGI1, and promotes its ER export and expression at the overall neuronal cell surface. Live-cell imaging indicated that LGI1 is co-transported in axonal vesicles with ADAM22 or ADAM23. Finally, we showed that ADAM22 and ADAM23 also associate with Caspr2 and TAG-1 to be selectively targeted within different axonal sub-regions. So, the combinatorial expression of Kv1-associated CAMs may be critical to tune intrinsic excitability in physiological or epileptogenic context.
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Affiliation(s)
- Bruno Hivert
- Aix Marseille Université, INSERM UMR1249, F-13273 Marseille, France
- Present address: Aix Marseille Université, CNRS UMR7289, Institut de Neurosciences de la Timone, F-13385 Marseille, France
| | - Laurène Marien
- Aix Marseille Université, INSERM UMR1249, F-13273 Marseille, France
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