101
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Lee JY, Kim MJ, Li L, Velumian AA, Aui PM, Fehlings MG, Petratos S. Nogo receptor 1 regulates Caspr distribution at axo-glial units in the central nervous system. Sci Rep 2017; 7:8958. [PMID: 28827698 PMCID: PMC5567129 DOI: 10.1038/s41598-017-09405-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/24/2017] [Indexed: 11/09/2022] Open
Abstract
Axo-glial units are highly organised microstructures propagating saltatory conduction and are disrupted during multiple sclerosis (MS). Nogo receptor 1 (NgR1) has been suggested to govern axonal damage during the progression of disease in the MS-like mouse model, experimental autoimmune encephalomyelitis (EAE). Here we have identified that adult ngr1 -/- mice, previously used in EAE and spinal cord injury experiments, display elongated paranodes, and nodes of Ranvier. Unstructured paranodal regions in ngr1 -/- mice are matched with more distributed expression pattern of Caspr. Compound action potentials of optic nerves and spinal cords from naïve ngr1 -/- mice are delayed and reduced. Molecular interaction studies revealed enhanced Caspr cleavage. Our data suggest that NgR1 may regulate axo-myelin ultrastructure through Caspr-mediated adhesion, regulating the electrophysiological signature of myelinated axons of central nervous system (CNS).
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Affiliation(s)
- Jae Young Lee
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia
- ToolGen, Inc., #1204, Byucksan Digital Valley 6-cha, Seoul, South Korea
| | - Min Joung Kim
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia
| | - Lijun Li
- Krembil Research Institute, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Alexander A Velumian
- Krembil Research Institute, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Krembil Neuroscience Centre, University Health Network, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Pei Mun Aui
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia
| | - Michael G Fehlings
- Krembil Research Institute, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Krembil Neuroscience Centre, University Health Network, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Steven Petratos
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia.
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102
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Coban H, Tung S, Yoo B, Vinters HV, Hinman JD. Molecular Disorganization of Axons Adjacent to Human Cortical Microinfarcts. Front Neurol 2017; 8:405. [PMID: 28861035 PMCID: PMC5561009 DOI: 10.3389/fneur.2017.00405] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 07/28/2017] [Indexed: 11/24/2022] Open
Abstract
Cortical microinfarcts (CMIs) are microscopically identified wedge-shaped ischemic lesions that occur at or near the cortical surface and result from occlusion of penetrating arterioles. These microscopic lesions can be observed with high-resolution magnetic resonance imaging in aging brains and in patients with cerebrovascular disease. Recent studies have suggested that strategically located microinfarcts strongly correlate with cognitive deficits, which can contribute to Alzheimer’s disease as well as other forms of dementia. We have recently shown that the molecular organization of axons into functional microdomains is altered in areas adjacent to white matter lacunar and microinfarcts, creating a peri-infarct penumbral injury in surviving axons. Whether similar changes in nodal, adjacent paranodal, and proximal axon initial segment molecular organization occur in the cortex adjacent to human CMIs is not known. Paraffin-embedded sections of autopsy brain tissue from five patients with CMIs were immunofluorescently labeled for nodal and paranodal markers including beta-IV spectrin, ankyrin-G, and contactin-associated protein. High magnification images from the peri-infarct cortical tissue were generated using confocal microscopy. In surviving cortical tissue adjacent to microinfarcts, we observed a dramatic loss of axon initial segments, suggesting that neuronal firing capacity in adjacent cortical tissue is likely compromised. The number of identifiable nodal/paranodal complexes in surviving cortical tissue is reduced adjacent to microinfarcts, while the average paranodal length is increased indicating a breakdown of axoglial contact. This axonal microdomain disorganization occurs in the relative absence of changes in the structural integrity of myelinated axons as measured by myelin basic protein and neurofilament staining. These findings indicate that the molecular organization of surviving axons adjacent to human CMIs is abnormal, reflecting lost axoglial contact and the functional elements necessary for neural transmission. This study provides support for the concept of a microinfarct penumbral injury that may account for the cumulative cognitive effect of these tiny strokes.
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Affiliation(s)
- Hamza Coban
- Department of Pathology and Laboratory Medicine, Section of Neuropathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Spencer Tung
- Department of Pathology and Laboratory Medicine, Section of Neuropathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Bryan Yoo
- Department of Radiology, Division of Neuroradiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Harry V Vinters
- Department of Pathology and Laboratory Medicine, Section of Neuropathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States.,Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Jason D Hinman
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
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103
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Manso Y, Holland PR, Kitamura A, Szymkowiak S, Duncombe J, Hennessy E, Searcy JL, Marangoni M, Randall AD, Brown JT, McColl BW, Horsburgh K. Minocycline reduces microgliosis and improves subcortical white matter function in a model of cerebral vascular disease. Glia 2017; 66:34-46. [PMID: 28722234 DOI: 10.1002/glia.23190] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 12/19/2022]
Abstract
Chronic cerebral hypoperfusion is a key mechanism associated with white matter disruption in cerebral vascular disease and dementia. In a mouse model relevant to studying cerebral vascular disease, we have previously shown that cerebral hypoperfusion disrupts axon-glial integrity and the distribution of key paranodal and internodal proteins in subcortical myelinated axons. This disruption of myelinated axons is accompanied by increased microglia and cognitive decline. The aim of the present study was to investigate whether hypoperfusion impairs the functional integrity of white matter, its relation with axon-glial integrity and microglial number, and whether by targeting microglia these effects can be improved. We show that in response to increasing durations of hypoperfusion, the conduction velocity of myelinated fibres in the corpus callosum is progressively reduced and that paranodal and internodal axon-glial integrity is disrupted. The number of microglial cells increases in response to hypoperfusion and correlates with disrupted paranodal and internodal integrity and reduced conduction velocities. Further minocycline, a proposed anti-inflammatory and microglia inhibitor, restores white matter function related to a reduction in the number of microglia. The study suggests that microglial activation contributes to the structural and functional alterations of myelinated axons induced by cerebral hypoperfusion and that dampening microglia numbers/proliferation should be further investigated as potential therapeutic benefit in cerebral vascular disease.
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Affiliation(s)
- Yasmina Manso
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Philip R Holland
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Akihiro Kitamura
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Stefan Szymkowiak
- University of Edinburgh, The Roslin Institute, Easter Bush, Edinburgh, EH25 9RG
| | - Jessica Duncombe
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Edel Hennessy
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - James L Searcy
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Martina Marangoni
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Andrew D Randall
- University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Jon T Brown
- University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Barry W McColl
- University of Edinburgh, The Roslin Institute, Easter Bush, Edinburgh, EH25 9RG.,UK Dementia Research Institute, University of Edinburgh, Edinburgh Medical School, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Karen Horsburgh
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
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104
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Autoantibodies in chronic inflammatory neuropathies: diagnostic and therapeutic implications. Nat Rev Neurol 2017; 13:533-547. [PMID: 28708133 DOI: 10.1038/nrneurol.2017.84] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The chronic inflammatory neuropathies (CINs) are rare, very disabling autoimmune disorders that generally respond well to immune therapies such as intravenous immunoglobulin (IVIg). The most common forms of CIN are chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy, and polyneuropathy associated with monoclonal gammopathy of unknown significance. The field of CIN has undergone a major advance with the identification of IgG4 autoantibodies directed against paranodal proteins in patients with CIDP. Although these autoantibodies are only found in a small subset of patients with CIDP, they can be used to guide therapeutic decision-making, as these patients have a poor response to IVIg. These observations provide proof of concept that identifying the target antigens in tissue-specific antibody-mediated autoimmune diseases is important, not only to understand their underlying pathogenic mechanisms, but also to correctly diagnose and treat affected patients. This state-of-the-art Review focuses on the role of autoantibodies against nodes of Ranvier in CIDP, a clinically relevant emerging field of research. The role of autoantibodies in other immune-mediated neuropathies, including other forms of CIN, primary autoimmune neuropathies, neoplasms, and systemic diseases that resemble CIN, are also discussed.
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105
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Manduca Contactin Regulates Amyloid Precursor Protein-Dependent Neuronal Migration. J Neurosci 2017; 36:8757-75. [PMID: 27535920 DOI: 10.1523/jneurosci.0729-16.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/12/2016] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED Amyloid precursor protein (APP) was originally identified as the source of β-amyloid peptides that accumulate in Alzheimer's disease (AD), but it also has been implicated in the control of multiple aspects of neuronal motility. APP belongs to an evolutionarily conserved family of transmembrane proteins that can interact with a variety of adapter and signaling molecules. Recently, we showed that both APP and its insect ortholog [APPL (APP-Like)] directly bind the heterotrimeric G-protein Goα, supporting the model that APP can function as an unconventional Goα-coupled receptor. We also adapted a well characterized assay of neuronal migration in the hawkmoth, Manduca sexta, to show that APPL-Goα signaling restricts ectopic growth within the developing nervous system, analogous to the role postulated for APP family proteins in controlling migration within the mammalian cortex. Using this assay, we have now identified Manduca Contactin (MsContactin) as an endogenous ligand for APPL, consistent with previous work showing that Contactins interact with APP family proteins in other systems. Using antisense-based knockdown protocols and fusion proteins targeting both proteins, we have shown that MsContactin is selectively expressed by glial cells that ensheath the migratory neurons (expressing APPL), and that MsContactin-APPL interactions normally prevent inappropriate migration and outgrowth. These results provide new evidence that Contactins can function as authentic ligands for APP family proteins that regulate APP-dependent responses in the developing nervous system. They also support the model that misregulated Contactin-APP interactions might provoke aberrant activation of Goα and its effectors, thereby contributing to the neurodegenerative sequelae that typify AD. SIGNIFICANCE STATEMENT Members of the amyloid precursor protein (APP) family participate in many aspects of neuronal development, but the ligands that normally activate APP signaling have remained controversial. This research provides new evidence that members of the Contactin family function as authentic ligands for APP and its orthologs, and that this evolutionarily conserved class of membrane-attached proteins regulates key aspects of APP-dependent migration and outgrowth in the embryonic nervous system. By defining the normal role of Contactin-APP signaling during development, these studies also provide the framework for investigating how the misregulation of Contactin-APP interactions might contribute to neuronal dysfunction in the context of both normal aging and neurodegenerative conditions, including Alzheimer's disease.
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106
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Furuse M, Izumi Y. Molecular dissection of smooth septate junctions: understanding their roles in arthropod physiology. Ann N Y Acad Sci 2017. [DOI: 10.1111/nyas.13366] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Mikio Furuse
- Division of Cell Structure; National Institute for Physiological Sciences; Okazaki Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki Japan
| | - Yasushi Izumi
- Division of Cell Structure; National Institute for Physiological Sciences; Okazaki Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki Japan
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107
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Vallat JM, Nizon M, Magee A, Isidor B, Magy L, Péréon Y, Richard L, Ouvrier R, Cogné B, Devaux J, Zuchner S, Mathis S. Contactin-Associated Protein 1 (CNTNAP1) Mutations Induce Characteristic Lesions of the Paranodal Region. J Neuropathol Exp Neurol 2017; 75:1155-1159. [PMID: 27818385 DOI: 10.1093/jnen/nlw093] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Congenital hypomyelinating neuropathy is a rare neonatal syndrome responsible for hypotonia and weakness. Nerve microscopic examination shows amyelination or hypomyelination. Recently, mutations in CNTNAP1 have been described in a few patients. CNTNAP1 encodes contactin-associated protein 1 (caspr-1), which is an essential component of the paranodal junctions of the peripheral and central nervous systems, and is necessary for the establishment of transverse bands that stabilize paranodal axo-glial junctions. We present the results of nerve biopsy studies of three patients from two unrelated, non-consanguineous families with compound heterozygous CNTNAP1 mutations. The lesions were identical, characterized by a hypomyelinating process; on electron microscopy, we detected, in all nodes of Ranvier, subtle lesions that have never been previously described in human nerves. Transverse bands of the myelin loops were absent, with a loss of attachment between myelin and the axolemma; elongated Schwann cell processes sometimes dissociated the Schwann cell and axon membranes that bound the space between them. These lesions were observed in the area where caspr-1 is located and are reminiscent of the lesions reported in sciatic nerves of caspr-1 null mice. CNTNAP1 mutations appear to induce characteristic ultrastructural lesions of the paranodal region.
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Affiliation(s)
- Jean-Michel Vallat
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Mathilde Nizon
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Alex Magee
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Bertrand Isidor
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Laurent Magy
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Yann Péréon
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Laurence Richard
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Robert Ouvrier
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Benjamin Cogné
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Jérôme Devaux
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Stephan Zuchner
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
| | - Stéphane Mathis
- From the Department of Neurology and 'Centre de Référence des neuropathies rares', University Hospital (CHU) Limoges, Limoges, France (JMV, LM and LR); Department of Medical Genetics, University Hospital (CHU) Nantes, Nantes, France (MN, BI and BC); Northern Ireland Regional Genetics Service, Belfast City Hospital, Belfast, Northern Ireland (AM); Centre de Référence des Maladies Neuromusculaires, Hôtel Dieu Hospital, Nantes, France (YP); The Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia (RO); CNRS, CRN2M-UMR 7286, Aix-Marseille University, Marseille, France (JD); Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida (SZ); Department of Neurology, Nerve-Muscle Unit, University Hospital (CHU) Pellegrin, Bordeaux, France (SM)
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Kianfar P, Abolfathi N, Karimi NZ. Investigating the effect of different transducer stiffness values on the contactin complex detachment by steered molecular dynamics. J Mol Graph Model 2017. [PMID: 28651183 DOI: 10.1016/j.jmgm.2017.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This study investigated the adhesion behavior of Contactin4 (CNTN4), a member of Immunoglobulin Super Family (Ig-SF) of cell adhesion molecules. Contactin4 plays a crucial role in the formation, maintenance, and plasticity of neuronal networks. Contactin in its complex configuration with protein tyrosine phosphatase gamma (PTPRG) was selected for simulation. By utilizing Steered Molecular Dynamics (SMD), the uniaxial force was applied to induce unbinding of the complex, and the force-induced detachment of complex components was probed. Three sets of simulations with three values of transducer stiffness and five pulling speeds were designed. Our results showed the dependence of unbinding force on both accessible parameters of pulling speed and spring stiffness. By increasing the stiffness value and pulling speed the rupture force increased. Accordingly, the dissociation rates due to the Bell's theory based on rupture forces and loading rates were calculated.
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Affiliation(s)
- Parnian Kianfar
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran 158754413, Iran.
| | - Nabiollah Abolfathi
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran 158754413, Iran
| | - Navid Zarif Karimi
- Department of Industrial Engineering, Università di Bologna, Bologna 40126, Italy
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109
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Nelson AD, Jenkins PM. Axonal Membranes and Their Domains: Assembly and Function of the Axon Initial Segment and Node of Ranvier. Front Cell Neurosci 2017; 11:136. [PMID: 28536506 PMCID: PMC5422562 DOI: 10.3389/fncel.2017.00136] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/21/2017] [Indexed: 12/19/2022] Open
Abstract
Neurons are highly specialized cells of the nervous system that receive, process and transmit electrical signals critical for normal brain function. Here, we review the intricate organization of axonal membrane domains that facilitate rapid action potential conduction underlying communication between complex neuronal circuits. Two critical excitable domains of vertebrate axons are the axon initial segment (AIS) and the nodes of Ranvier, which are characterized by the high concentrations of voltage-gated ion channels, cell adhesion molecules and specialized cytoskeletal networks. The AIS is located at the proximal region of the axon and serves as the site of action potential initiation, while nodes of Ranvier, gaps between adjacent myelin sheaths, allow rapid propagation of the action potential through saltatory conduction. The AIS and nodes of Ranvier are assembled by ankyrins, spectrins and their associated binding partners through the clustering of membrane proteins and connection to the underlying cytoskeleton network. Although the AIS and nodes of Ranvier share similar protein composition, their mechanisms of assembly are strikingly different. Here we will cover the mechanisms of formation and maintenance of these axonal excitable membrane domains, specifically highlighting the similarities and differences between them. We will also discuss recent advances in super resolution fluorescence imaging which have elucidated the arrangement of the submembranous axonal cytoskeleton revealing a surprising structural organization necessary to maintain axonal organization and function. Finally, human mutations in axonal domain components have been associated with a growing number of neurological disorders including severe cognitive dysfunction, epilepsy, autism, neurodegenerative diseases and psychiatric disorders. Overall, this review highlights the assembly, maintenance and function of axonal excitable domains, particularly the AIS and nodes of Ranvier, and how abnormalities in these processes may contribute to disease.
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Affiliation(s)
- Andrew D Nelson
- Department of Pharmacology, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical SchoolAnn Arbor, MI, USA.,Department of Psychiatry, University of Michigan Medical SchoolAnn Arbor, MI, USA
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Brivio V, Faivre-Sarrailh C, Peles E, Sherman DL, Brophy PJ. Assembly of CNS Nodes of Ranvier in Myelinated Nerves Is Promoted by the Axon Cytoskeleton. Curr Biol 2017; 27:1068-1073. [PMID: 28318976 PMCID: PMC5387178 DOI: 10.1016/j.cub.2017.01.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 12/17/2016] [Accepted: 01/12/2017] [Indexed: 11/02/2022]
Abstract
Nodes of Ranvier in the axons of myelinated neurons are exemplars of the specialized cell surface domains typical of polarized cells. They are rich in voltage-gated sodium channels (Nav) and thus underpin rapid nerve impulse conduction in the vertebrate nervous system [1]. Although nodal proteins cluster in response to myelination, how myelin-forming glia influence nodal assembly is poorly understood. An axoglial adhesion complex comprising glial Neurofascin155 and axonal Caspr/Contactin flanks mature nodes [2]. We have shown that assembly of this adhesion complex at the extremities of migrating oligodendroglial processes promotes process convergence along the axon during central nervous system (CNS) node assembly [3]. Here we show that anchorage of this axoglial complex to the axon cytoskeleton is essential for efficient CNS node formation. When anchorage is disrupted, both the adaptor Protein 4.1B and the cytoskeleton protein βII spectrin are mislocalized in the axon, and assembly of the node of Ranvier is significantly delayed. Nodal proteins and migrating oligodendroglial processes are no longer juxtaposed, and single detached nodal complexes replace the symmetrical heminodes found in both the CNS and peripheral nervous system (PNS) during development. We propose that axoglial adhesion complexes contribute to the formation of an interface between cytoskeletal elements enriched in Protein 4.1B and βII spectrin and those enriched in nodal ankyrinG and βIV spectrin. This clusters nascent nodal complexes at heminodes and promotes their timely coalescence to form the mature node of Ranvier. These data demonstrate a role for the axon cytoskeleton in the assembly of a critical neuronal domain, the node of Ranvier.
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Affiliation(s)
- Veronica Brivio
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Catherine Faivre-Sarrailh
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille-UMR 7286, CNRS, 13344 Marseille, France
| | - Elior Peles
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Diane L Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK.
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111
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Saifetiarova J, Liu X, Taylor AM, Li J, Bhat MA. Axonal domain disorganization in Caspr1 and Caspr2 mutant myelinated axons affects neuromuscular junction integrity, leading to muscle atrophy. J Neurosci Res 2017; 95:1373-1390. [PMID: 28370195 DOI: 10.1002/jnr.24052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/14/2017] [Accepted: 02/24/2017] [Indexed: 12/19/2022]
Abstract
Bidirectional interactions between neurons and myelinating glial cells result in formation of axonal domains along myelinated fibers. Loss of axonal domains leads to detrimental consequences on nerve structure and function, resulting in reduced conductive properties and the diminished ability to reliably transmit signals to the targets they innervate. Thus, impairment of peripheral myelinated axons that project to the surface of muscle fibers and form neuromuscular junction (NMJ) synapses leads to muscle dysfunction. The goal of our studies was to determine how altered electrophysiological properties due to axonal domain disorganization lead to muscle pathology, which is relevant to a variety of peripheral neuropathies, demyelinating diseases, and neurodegenerative disorders. Using conventional Contactin-Associated Protein 1 (Caspr1) and Caspr2 single or double mutants with disrupted paranodal, juxtaparanodal, or both regions, respectively, in peripheral myelinated axons, we correlated defects in NMJ integrity and muscle pathology. Our data show that loss of axonal domains in Caspr1 and Caspr2 single and double mutants primarily alters distal myelinated fibers together with presynaptic terminals, eventually leading to NMJ denervation and reduction in postsynaptic endplate areas. Moreover, reduction in conductive properties of peripheral myelinated fibers together with NMJ disintegration leads to muscle atrophy in Caspr1 mutants or muscle fiber degeneration accompanied by mitochondrial dysfunction in Caspr1/Caspr2 double mutants. Together, our data indicate that proper organization of axonal domains in myelinated fibers is critical for optimal propagation of electrical signals, NMJ integrity, and muscle health, and provide insights into a wide range of pathologies that result in reduced nerve conduction leading to muscle atrophy. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Julia Saifetiarova
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Xi Liu
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas.,Xiangya School of Medicine, Central South University, Changsha, China
| | - Anna M Taylor
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Jie Li
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
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Hengel H, Magee A, Mahanjah M, Vallat JM, Ouvrier R, Abu-Rashid M, Mahamid J, Schüle R, Schulze M, Krägeloh-Mann I, Bauer P, Züchner S, Sharkia R, Schöls L. CNTNAP1 mutations cause CNS hypomyelination and neuropathy with or without arthrogryposis. NEUROLOGY-GENETICS 2017; 3:e144. [PMID: 28374019 PMCID: PMC5363873 DOI: 10.1212/nxg.0000000000000144] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/06/2017] [Indexed: 11/17/2022]
Abstract
Objective: To explore the phenotypic spectrum and pathophysiology of human disease deriving from mutations in the CNTNAP1 gene. Methods: In a field study on consanguineous Palestinian families, we identified 3 patients carrying homozygous mutations in the CNTNAP1 gene using whole-exome sequencing. An unrelated Irish family was detected by screening the GENESIS database for further CNTNAP1 mutations. Neurophysiology, MRI, and nerve biopsy including electron microscopy were performed for deep phenotyping. Results: We identified 3 novel CNTNAP1 mutations in 5 patients from 2 families: c.2015G>A:p.(Trp672*) in a homozygous state in family 1 and c.2011C>T:p.(Gln671*) in a compound heterozygous state with c.2290C>T:p.(Arg764Cys) in family 2. Affected patients suffered from a severe CNS disorder with hypomyelinating leukodystrophy and peripheral neuropathy of sensory-motor type. Arthrogryposis was present in 2 patients but absent in 3 patients. Brain MRI demonstrated severe hypomyelination and secondary cerebral and cerebellar atrophy as well as a mega cisterna magna and corpus callosum hypoplasia. Nerve biopsy revealed very distinct features with lack of transverse bands at the paranodes and widened paranodal junctional gaps. Conclusions: CNTNAP1 mutations have recently been linked to patients with arthrogryposis multiplex congenita. However, we show that arthrogryposis is not an obligate feature. CNTNAP1-related disorders are foremost severe hypomyelinating disorders of the CNS and the peripheral nervous system. The pathology is partly explained by the involvement of CNTNAP1 in the proper formation and preservation of paranodal junctions and partly by the assumed role of CNTNAP1 as a key regulator in the development of the cerebral cortex.
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Affiliation(s)
- Holger Hengel
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Alex Magee
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Muhammad Mahanjah
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Jean-Michel Vallat
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Robert Ouvrier
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Mohammad Abu-Rashid
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Jamal Mahamid
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Rebecca Schüle
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Martin Schulze
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Ingeborg Krägeloh-Mann
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Peter Bauer
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Stephan Züchner
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Rajech Sharkia
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
| | - Ludger Schöls
- Department of Neurology and Hertie-Institute for Clinical Brain Research (H.H., R. Schüle, L.S.), University of Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE) (H.H., R.S., L.S.), Tübingen, Germany; Northern Ireland Regional Genetics Service (A.M.), Belfast City Hospital, Belfast; Department of Neurology (J.-M.V.), National Reference Center for Rare Peripheral Neuropathies, University Hospital, Limoges, France; Institute for Neuroscience and Muscle Research (R.O.), The Children's Hospital at Westmead, Sydney, New South Wales, Australia; The Triangle Regional Research and Development Center (R. Sharkia), Kfar Qari' Israel; Beit-Berl Academic College (R. Sharkia), Israel; Child Neurology and Development Center (M.M.), Hillel-Yaffe Medical Center, Hadera, Israel; Rappaport Faculty of Medicine (M.M.), Technion, Haifa, Israel; Institute of Medical Genetics and Applied Genomics (M.S.), University of Tübingen, Germany; Department of Pediatric Neurology (I.K.-M.), University Medical Center Tübingen, Germany; Hussman Institute for Human Genomics (S.Z.), University of Miami Miller School of Medicine, FL; Clalit Health Services (M.A.-R.), Haifa, Israel; and Meuhedet Health Services (J.M.), North District, Israel
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Maglemose R, Hedegaard A, Lehnhoff J, Dimintiyanova KP, Moldovan M, Grøndahl L, Meehan CF. Potassium channel abnormalities are consistent with early axon degeneration of motor axons in the G127X SOD1 mouse model of amyotrophic lateral sclerosis. Exp Neurol 2017; 292:154-167. [PMID: 28322742 DOI: 10.1016/j.expneurol.2017.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 02/21/2017] [Accepted: 03/14/2017] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disease, which selectively affects upper and lower motoneurones. The underlying pathophysiology of the disease is complex but electrophysiological studies of peripheral nerves in ALS patients as well as human autopsy studies indicate that a potassium channel dysfunction/loss is present early in the symptomatic phase. It remains unclear to what extent potassium channel abnormalities reflect a specific pathogenic mechanism in ALS. The aim of this study was therefore to investigate the temporal changes in the expression and/or function of potassium channels in motoneurones in the adult G127X SOD1 mouse model of ALS, a model which has a very long presymptomatic phase. Evidence from animal models indicates that the early progressive motoneurone dysfunction and degeneration can be largely compensated by motor unit remodeling, delaying the clinical symptom onset. Experiments were therefore performed both before and after symptom onset. Immunohistochemistry of motor axons in the ventral roots of G127X SOD1 mice, was used to investigate juxta-paranodal Kv1.2 potassium channels along with nodal Nav1.6 and the paranodal scaffolding protein Caspr. This allowed an investigation of changes in the distribution of Kv1.2 relative to the general structure of the nodal-paranodal-juxta-paranodal complex. This revealed that the motor axons in the ventral roots of presymptomatic G127X SOD1 mice, already show a disruption in juxta-paranodal Kv1.2 potassium channels. The axonal Kv1.2 disruption was preceded by abnormalities in the distribution of the paranodal scaffolding protein Caspr with the nodal arrangement of Nav1.6 appearing relatively preserved even in symptomatic mice. These changes were accompanied by axon swelling and a slowing of conduction in the peripheral motor axons in symptomatic mice. In vivo electrophysiological intracellular recordings of individual spinal motoneurones revealed that central potassium channel function was preserved or even enhanced with higher amplitude and longer duration after-hyperpolarisations in the G127X SOD1 mice. Our data suggest that the potassium channel abnormalities observed in presymptomatic G127X, rather than representing a specific pathophysiological mechanism targeting potassium channels, most likely reflect early axonal degenerative changes, consistent with the "dying-back" phenomenon observed in other ALS models.
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Affiliation(s)
- Rikke Maglemose
- Centre for Neuroscience, Copenhagen University, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Anne Hedegaard
- Centre for Neuroscience, Copenhagen University, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Janna Lehnhoff
- Centre for Neuroscience, Copenhagen University, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | | | - Mihai Moldovan
- Centre for Neuroscience, Copenhagen University, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Lillian Grøndahl
- Centre for Neuroscience, Copenhagen University, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Claire Francesca Meehan
- Centre for Neuroscience, Copenhagen University, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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114
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Carroll SL. The Molecular and Morphologic Structures That Make Saltatory Conduction Possible in Peripheral Nerve. J Neuropathol Exp Neurol 2017; 76:255-257. [DOI: 10.1093/jnen/nlx013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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115
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Vallat JM, Yuki N, Sekiguchi K, Kokubun N, Oka N, Mathis S, Magy L, Sherman DL, Brophy PJ, Devaux JJ. Paranodal lesions in chronic inflammatory demyelinating polyneuropathy associated with anti-Neurofascin 155 antibodies. Neuromuscul Disord 2017; 27:290-293. [DOI: 10.1016/j.nmd.2016.10.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/04/2016] [Accepted: 10/18/2016] [Indexed: 11/29/2022]
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116
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Lakhani S, Doan R, Almureikhi M, Partlow JN, Al Saffar M, Elsaid MF, Alaaraj N, James Barkovich A, Walsh CA, Ben-Omran T. Identification of a novel CNTNAP1 mutation causing arthrogryposis multiplex congenita with cerebral and cerebellar atrophy. Eur J Med Genet 2017; 60:245-249. [PMID: 28254648 DOI: 10.1016/j.ejmg.2017.02.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 02/01/2017] [Accepted: 02/26/2017] [Indexed: 01/18/2023]
Abstract
Arthrogryposis multiplex congenital, the occurrence of multiple joint contractures at birth, can in some cases be accompanied by insufficient myelination of peripheral nerves, muscular hypotonia, reduced tendon reflexes, and respiratory insufficiency. Recently mutations in the CASPR/CNTN1 complex have been associated with similar severe phenotypes and CNTNAP1 gene mutations, causing loss of the CASPR protein, were shown to cause severe, prenatal onset arthrogryposis multiplex congenita in four unrelated families. Here we report a consanguineous Arab family from Qatar with three children having an early lethal form of arthrogryposis multiplex congenita and a novel frameshift mutation in CNTNAP1. We further expand the existing CNTNAP1-associated phenotype to include profound cerebral and cerebellar atrophy.
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Affiliation(s)
- Shenela Lakhani
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | - Ryan Doan
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Mariam Almureikhi
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | - Jennifer N Partlow
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA, 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Muna Al Saffar
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA, 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, 02115, USA; Department of Pediatrics, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Mahmoud F Elsaid
- Section of Neurology, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | - Nada Alaaraj
- Section of Children Development and Rehabilitation, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | - A James Barkovich
- Pediatric Neuroradiology, Department of Neuroradiology, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA, 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, 02115, USA; Harvard Medical School, Boston, MA, 02115, USA
| | - Tawfeg Ben-Omran
- Section of Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Qatar.
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117
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Weiler A, Volkenhoff A, Hertenstein H, Schirmeier S. Metabolite transport across the mammalian and insect brain diffusion barriers. Neurobiol Dis 2017; 107:15-31. [PMID: 28237316 DOI: 10.1016/j.nbd.2017.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 01/02/2017] [Accepted: 02/20/2017] [Indexed: 12/31/2022] Open
Abstract
The nervous system in higher vertebrates is separated from the circulation by a layer of specialized endothelial cells. It protects the sensitive neurons from harmful blood-derived substances, high and fluctuating ion concentrations, xenobiotics or even pathogens. To this end, the brain endothelial cells and their interlinking tight junctions build an efficient diffusion barrier. A structurally analogous diffusion barrier exists in insects, where glial cell layers separate the hemolymph from the neural cells. Both types of diffusion barriers, of course, also prevent influx of metabolites from the circulation. Because neuronal function consumes vast amounts of energy and necessitates influx of diverse substrates and metabolites, tightly regulated transport systems must ensure a constant metabolite supply. Here, we review the current knowledge about transport systems that carry key metabolites, amino acids, lipids and carbohydrates into the vertebrate and Drosophila brain and how this transport is regulated. Blood-brain and hemolymph-brain transport functions are conserved and we can thus use a simple, genetically accessible model system to learn more about features and dynamics of metabolite transport into the brain.
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Affiliation(s)
- Astrid Weiler
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Anne Volkenhoff
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Helen Hertenstein
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany.
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118
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Schwabe T, Li X, Gaul U. Dynamic analysis of the mesenchymal-epithelial transition of blood-brain barrier forming glia in Drosophila. Biol Open 2017; 6:232-243. [PMID: 28108476 PMCID: PMC5312092 DOI: 10.1242/bio.020669] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During development, many epithelia are formed by a mesenchymal-epithelial transition (MET). Here, we examine the major stages and underlying mechanisms of MET during blood-brain barrier formation in Drosophila. We show that contact with the basal lamina is essential for the growth of the barrier-forming subperineurial glia (SPG). Septate junctions (SJs), which provide insulation of the paracellular space, are not required for MET, but are necessary for the establishment of polarized SPG membrane compartments. In vivo time-lapse imaging reveals that the Moody GPCR signaling pathway regulates SPG cell growth and shape, with different levels of signaling causing distinct phenotypes. Timely, well-coordinated SPG growth is essential for the uniform insertion of SJs and thus the insulating function of the barrier. To our knowledge, this is the first dynamic in vivo analysis of all stages in the formation of a secondary epithelium, and of the key role trimeric G protein signaling plays in this important morphogenetic process. Summary: This study examines the major steps and underlying mechanisms of mesenchymal-epithelial transition of the blood-brain-barrier forming glia in Drosophila, including the role of basal lamina, septate junctions and of trimeric G protein signaling.
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Affiliation(s)
- Tina Schwabe
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Xiaoling Li
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany.,Rockefeller University, 1230 York Ave, New York, 10065-6399 NY, USA
| | - Ulrike Gaul
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany
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119
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Mehta P, Küspert M, Bale T, Brownstein CA, Towne MC, De Girolami U, Shi J, Beggs AH, Darras BT, Wegner M, Piao X, Agrawal PB. Novel mutation in CNTNAP1 results in congenital hypomyelinating neuropathy. Muscle Nerve 2017; 55:761-765. [PMID: 27668699 DOI: 10.1002/mus.25416] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2016] [Indexed: 01/29/2023]
Abstract
INTRODUCTION Congenital hypomyelinating neuropathy (CHN) is a rare congenital neuropathy that presents in the neonatal period and has been linked previously to mutations in several genes associated with myelination. A recent study has linked 4 homozygous frameshift mutations in the contactin-associated protein 1 (CNTNAP1) gene with this condition. METHODS We report a neonate with CHN who was found to have absent sensory nerve and compound muscle action potentials and hypomyelination on nerve biopsy. RESULTS On whole exome sequencing, we identified a novel CNTNAP1 homozygous missense mutation (p.Arg388Pro) in the proband, and both parents were carriers. Molecular modeling suggests that this variant disrupts a β-strand to cause an unstable structure and likely significant changes in protein function. CONCLUSIONS This report links a missense CNTNAP1 variant to the disease phenotype previously associated only with frameshift mutations. Muscle Nerve 55: 761-765, 2017.
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Affiliation(s)
- Paulomi Mehta
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, 300 Longwood Avenue, Harvard Medical School, Boston, Massachusetts, 02115, USA
| | - Melanie Küspert
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Tejus Bale
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Catherine A Brownstein
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Meghan C Towne
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Umberto De Girolami
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jiahai Shi
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong
| | - Alan H Beggs
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Basil T Darras
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael Wegner
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Xianhua Piao
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, 300 Longwood Avenue, Harvard Medical School, Boston, Massachusetts, 02115, USA
| | - Pankaj B Agrawal
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, 300 Longwood Avenue, Harvard Medical School, Boston, Massachusetts, 02115, USA
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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120
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Taylor AM, Saifetiarova J, Bhat MA. Postnatal Loss of Neuronal and Glial Neurofascins Differentially Affects Node of Ranvier Maintenance and Myelinated Axon Function. Front Cell Neurosci 2017; 11:11. [PMID: 28217083 PMCID: PMC5289982 DOI: 10.3389/fncel.2017.00011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
Intricate molecular interactions between neurons and glial cells underlie the creation of unique domains that are essential for saltatory conduction of action potentials by myelinated axons. Previously, the cell surface adhesion molecule Neurofascin (Nfasc) has been shown to have a dual-role in the establishment of axonal domains from both the glial and neuronal interface. While the neuron-specific isoform of Neurofascin (NF186) is indispensable for clustering of voltage-gated sodium channels at nodes of Ranvier; the glial-specific isoform of Neurofascin (NF155) is required for myelinating glial cells to organize the paranodal domain. Although many studies have addressed the individual roles of NF155 and NF186 in assembling paranodes and nodes, respectively; critical questions about their roles in the maintenance and long-term health of the myelinated axons remain, which we aimed to address in these studies. Here using spatiotemporal ablation of Neurofascin in neurons alone or together with myelinating glia, we report that loss of NF186 individually from postnatal mice leads to progressive nodal destabilization and axonal degeneration. While individual ablation of paranodal NF155 does not disrupt nodes of Ranvier; loss of NF186 combined with NF155 causes more accelerated nodal destabilization than loss of NF186 alone, providing strong evidence regarding a supporting role for paranodes in nodal maintenance. In both cases of NF186 loss, myelinating axons show ultrastructural changes and degeneration. Our studies reveal that long-term maintenance of nodes and ultimately the health of axons is correlated with the stability of NF186 within the nodal complex and the presence of auxiliary paranodes.
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Affiliation(s)
- Anna M Taylor
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center San Antonio, TX, USA
| | - Julia Saifetiarova
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center San Antonio, TX, USA
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center San Antonio, TX, USA
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121
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Wu ZQ, Li D, Huang Y, Chen XP, Huang W, Liu CF, Zhao HQ, Xu RX, Cheng M, Schachner M, Ma QH. Caspr Controls the Temporal Specification of Neural Progenitor Cells through Notch Signaling in the Developing Mouse Cerebral Cortex. Cereb Cortex 2017; 27:1369-1385. [PMID: 26740489 DOI: 10.1093/cercor/bhv318] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The generation of layer-specific neurons and astrocytes by radial glial cells during development of the cerebral cortex follows a precise temporal sequence, which is regulated by intrinsic and extrinsic factors. The molecular mechanisms controlling the timely generation of layer-specific neurons and astrocytes remain not fully understood. In this study, we show that the adhesion molecule contactin-associated protein (Caspr), which is involved in the maintenance of the polarized domains of myelinated axons, is essential for the timing of generation of neurons and astrocytes in the developing mouse cerebral cortex. Caspr is expressed by radial glial cells, which are neural progenitor cells that generate both neurons and astrocytes. Absence of Caspr in neural progenitor cells delays the production cortical neurons and induces precocious formation of cortical astrocytes, without affecting the numbers of progenitor cells. At the molecular level, Caspr cooperates with the intracellular domain of Notch to repress transcription of the Notch effector Hes1. Suppression of Notch signaling via a Hes1 shRNA rescues the abnormal neurogenesis and astrogenesis in Caspr-deficient mice. These findings establish Caspr as a novel key regulator that controls the temporal specification of cell fate in radial glial cells of the developing cerebral cortex through Notch signaling.
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Affiliation(s)
- Zhi-Qiang Wu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu Province 215123, China
| | - Di Li
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu Province 215123, China
| | - Ya Huang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu Province 215123, China
| | - Xi-Ping Chen
- Department of Forensic Medicine, Soochow University, Suzhou, Jiangsu Province 215123, China
| | - Wenhui Huang
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Homburg D-66421, Germany
| | - Chun-Feng Liu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu Province 215123, China
| | - He-Qing Zhao
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu Province 215123, China
| | - Ru-Xiang Xu
- Affiliated Bayi Brain Hospital, Beijing Military Hospital, Southern Medical University, Beijing 100070, China
| | - Mei Cheng
- Binzhou Medical University, Yantai, Shandong Province 264000, China
| | - Melitta Schachner
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong Province 515041, China
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Second Affiliated Hospital, Soochow University, Suzhou, Jiangsu Province 215123, China
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Early and Late Loss of the Cytoskeletal Scaffolding Protein, Ankyrin G Reveals Its Role in Maturation and Maintenance of Nodes of Ranvier in Myelinated Axons. J Neurosci 2017; 37:2524-2538. [PMID: 28148727 DOI: 10.1523/jneurosci.2661-16.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 12/15/2016] [Accepted: 01/25/2017] [Indexed: 11/21/2022] Open
Abstract
The mechanisms that govern node of Ranvier organization, stability, and long-term maintenance remain to be fully elucidated. One of the molecular components of the node is the cytoskeletal scaffolding protein, ankyrin G (AnkG), which interacts with multiple members of the nodal complex. The role of AnkG in nodal organization and maintenance is still not clearly defined as to whether AnkG functions as an initial nodal organizer or whether it functions as a nodal stabilizer after the nodal complex has been assembled. Using a mouse model system, we report here that perinatal and juvenile neuronal ablation of AnkG has differential consequences on nodal stability. Early loss of AnkG creates immature nodes with abnormal morphology, which undergo accelerated destabilization within a month, resulting in rapid voltage-gated sodium (NaV) channel and βIV spectrin loss with reduced effects on neurofascin 186. On the other hand, late ablation of AnkG from established nodal complexes leads to slow but progressive nodal destabilization over 10 months, primarily affecting βIV spectrin, followed by NaV channels, with modest impact on neurofascin 186. We also show that ankyrin R and βI spectrin are not sufficient to prevent nodal disorganization after AnkG ablation. Additionally, nodal disorganization in both early and late AnkG mutants is accompanied by axonal pathology and neurological dysfunction. Together, our results suggest that AnkG plays an indispensable role in the maturation and long-term stabilization of the newly assembled nodal complex, and that loss of AnkG after nodal stabilization does not lead to rapid nodal disassembly but to loss of specific nodal components in a time-dependent manner.SIGNIFICANCE STATEMENT Nodes of Ranvier are the myelin-free gaps along myelinated axons that allow fast communication between neurons and their target cells by propagating action potentials in a saltatory manner. The cytoskeletal scaffolding protein ankyrin G (AnkG) has been thought to play an important role in node formation; however, its precise role in nodal assembly, stability, and maintenance is still not clear. By using spatiotemporal ablation of AnkG, we report its differential role in nodal maturation and stabilization. We show that early AnkG-deficient nodes fail to mature and undergo rapid destabilization. In contrast, nodes that assemble with AnkG are much more stable and undergo gradual disintegration with sequential loss of nodal components in the absence of AnkG.
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Amor V, Zhang C, Vainshtein A, Zhang A, Zollinger DR, Eshed-Eisenbach Y, Brophy PJ, Rasband MN, Peles E. The paranodal cytoskeleton clusters Na + channels at nodes of Ranvier. eLife 2017; 6. [PMID: 28134616 PMCID: PMC5279941 DOI: 10.7554/elife.21392] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/20/2017] [Indexed: 11/13/2022] Open
Abstract
A high density of Na+ channels at nodes of Ranvier is necessary for rapid and efficient action potential propagation in myelinated axons. Na+ channel clustering is thought to depend on two axonal cell adhesion molecules that mediate interactions between the axon and myelinating glia at the nodal gap (i.e., NF186) and the paranodal junction (i.e., Caspr). Here we show that while Na+ channels cluster at nodes in the absence of NF186, they fail to do so in double conditional knockout mice lacking both NF186 and the paranodal cell adhesion molecule Caspr, demonstrating that a paranodal junction-dependent mechanism can cluster Na+ channels at nodes. Furthermore, we show that paranode-dependent clustering of nodal Na+ channels requires axonal βII spectrin which is concentrated at paranodes. Our results reveal that the paranodal junction-dependent mechanism of Na+channel clustering is mediated by the spectrin-based paranodal axonal cytoskeleton.
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Affiliation(s)
- Veronique Amor
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Chuansheng Zhang
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Anna Vainshtein
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Ao Zhang
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel R Zollinger
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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124
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Bryan MR, Bowman AB. Manganese and the Insulin-IGF Signaling Network in Huntington's Disease and Other Neurodegenerative Disorders. ADVANCES IN NEUROBIOLOGY 2017; 18:113-142. [PMID: 28889265 PMCID: PMC6559248 DOI: 10.1007/978-3-319-60189-2_6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease resulting in motor impairment and death in patients. Recently, several studies have demonstrated insulin or insulin-like growth factor (IGF) treatment in models of HD, resulting in potent amelioration of HD phenotypes via modulation of the PI3K/AKT/mTOR pathways. Administration of IGF and insulin can rescue microtubule transport, metabolic function, and autophagy defects, resulting in clearance of Huntingtin (HTT) aggregates, restoration of mitochondrial function, amelioration of motor abnormalities, and enhanced survival. Manganese (Mn) is an essential metal to all biological systems but, in excess, can be toxic. Interestingly, several studies have revealed the insulin-mimetic effects of Mn-demonstrating Mn can activate several of the same metabolic kinases and increase peripheral and neuronal insulin and IGF-1 levels in rodent models. Separate studies have shown mouse and human striatal neuroprogenitor cell (NPC) models exhibit a deficit in cellular Mn uptake, indicative of a Mn deficiency. Furthermore, evidence from the literature reveals a striking overlap between cellular consequences of Mn deficiency (i.e., impaired function of Mn-dependent enzymes) and known HD endophenotypes including excitotoxicity, increased reactive oxygen species (ROS) accumulation, and decreased mitochondrial function. Here we review published evidence supporting a hypothesis that (1) the potent effect of IGF or insulin treatment on HD models, (2) the insulin-mimetic effects of Mn, and (3) the newly discovered Mn-dependent perturbations in HD may all be functionally related. Together, this review will present the intriguing possibility that intricate regulatory cross-talk exists between Mn biology and/or toxicology and the insulin/IGF signaling pathways which may be deeply connected to HD pathology and, perhaps, other neurodegenerative diseases (NDDs) and other neuropathological conditions.
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Affiliation(s)
- Miles R Bryan
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
| | - Aaron B Bowman
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Vanderbilt Center in Molecular Toxicology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
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Otani Y, Yermakov LM, Dupree JL, Susuki K. Chronic peripheral nerve compression disrupts paranodal axoglial junctions. Muscle Nerve 2016; 55:544-554. [PMID: 27463510 DOI: 10.1002/mus.25273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 07/13/2016] [Accepted: 07/26/2016] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Peripheral nerves are often exposed to mechanical stress leading to compression neuropathies. The pathophysiology underlying nerve dysfunction by chronic compression is largely unknown. METHODS We analyzed molecular organization and fine structures at and near nodes of Ranvier in a compression neuropathy model in which a silastic tube was placed around the mouse sciatic nerve. RESULTS Immunofluorescence study showed that clusters of cell adhesion complex forming paranodal axoglial junctions were dispersed and overlapped frequently with juxtaparanodal components. These paranodal changes occurred without internodal myelin damage. The distribution and pattern of paranodal disruption suggests that these changes are the direct result of mechanical stress. Electron microscopy confirmed loss of paranodal axoglial junctions. CONCLUSIONS Our data show that chronic nerve compression disrupts paranodal junctions and axonal domains required for proper peripheral nerve function. These results provide important clues toward better understanding of the pathophysiology underlying nerve dysfunction in compression neuropathies. Muscle Nerve 55: 544-554, 2017.
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Affiliation(s)
- Yoshinori Otani
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, 3640 Colonel Glenn Highway, Dayton, Ohio, 45435, USA
| | - Leonid M Yermakov
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, 3640 Colonel Glenn Highway, Dayton, Ohio, 45435, USA
| | - Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Keiichiro Susuki
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, 3640 Colonel Glenn Highway, Dayton, Ohio, 45435, USA
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126
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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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127
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Xu J, Berret E, Kim JH. Activity-dependent formation and location of voltage-gated sodium channel clusters at a CNS nerve terminal during postnatal development. J Neurophysiol 2016; 117:582-593. [PMID: 27832602 DOI: 10.1152/jn.00617.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/05/2016] [Indexed: 01/18/2023] Open
Abstract
In auditory pathways, the precision of action potential (AP) propagation depends on axon myelination and high densities of voltage-gated Na (Nav) channels clustered at nodes of Ranvier. Changes in Nav channel expression at the heminode, the final node before the nerve terminal, can alter AP invasion into the presynaptic terminal. We studied the activity-dependent formation of Nav channel clusters before and after hearing onset at postnatal day 12 in the rat and mouse auditory brain stem. In rats, the Nav channel cluster at the heminode formed progressively during the second postnatal week, around hearing onset, whereas the Nav channel cluster at the nodes was present before hearing onset. Initiation of heminodal Nav channel clustering was correlated with the expression of scaffolding protein ankyrinG and paranodal protein Caspr. However, in whirler mice with congenital deafness, heminodal Nav channels did not form clusters and maintained broad expression, but Nav channel clustering was normal at the nodes. In addition, a clear difference in the distance from the heminodal Nav channel to the calyx across the mediolateral axis of the medial nucleus of the trapezoid body (MNTB) developed after hearing onset. In the medial MNTB, where neurons respond best to high-frequency sounds, the heminodal Nav channel cluster was located closer to the terminal than in the lateral MNTB, where neurons respond best to low-frequency sounds. Thus sound-mediated neuronal activities are potentially associated with the refinement of the heminode adjacent to the presynaptic terminal in the auditory brain stem. NEW & NOTEWORTHY Clustering of voltage-gated sodium (Nav) channels and their distribution along the axon, specifically at the unmyelinated axon segment next to the nerve terminal, are essential for tuning propagated action potentials. Nav channel clusters near the nerve terminal and their location as a function of neuronal position along the mediolateral axis are controlled by auditory inputs after hearing onset. Thus sound-mediated neuronal activity influences the tonotopic organization of Nav channels at the nerve terminal in the auditory brain stem.
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Affiliation(s)
- Jie Xu
- The Department of Physiology, University of Texas Health Science Center, San Antonio, Texas; and
| | - Emmanuelle Berret
- The Department of Physiology, University of Texas Health Science Center, San Antonio, Texas; and
| | - Jun Hee Kim
- The Department of Physiology, University of Texas Health Science Center, San Antonio, Texas; and .,Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, Texas
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128
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Nizon M, Cogne B, Vallat JM, Joubert M, Liet JM, Simon L, Vincent M, Küry S, Boisseau P, Schmitt S, Mercier S, Bénéteau C, Larrose C, Coste M, Latypova X, Péréon Y, Mussini JM, Bézieau S, Isidor B. Two novel variants in CNTNAP1 in two siblings presenting with congenital hypotonia and hypomyelinating neuropathy. Eur J Hum Genet 2016; 25:150-152. [PMID: 27782105 DOI: 10.1038/ejhg.2016.142] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/29/2016] [Accepted: 09/20/2016] [Indexed: 01/06/2023] Open
Abstract
Homozygous frameshift variants in CNTNAP1 have recently been reported in patients with arthrogryposis and abnormal axon myelination. In two brothers with severe congenital hypotonia and foot deformities, we identified compound heterozygous variants in CNTNAP1, reporting the first causative missense variant, p.(Cys323Arg). Motor nerve conductions were markedly decreased. Nerve microscopical lesions confirmed a severe hypomyelinating process and showed loss of attachment sites of the myelin loops on the axons, which could be a characteristic of Caspr loss-of-function. We discuss the pathophysiology of the myelination process and we propose to consider this disorder as a congenital hypomyelinating neuropathy.
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Affiliation(s)
| | | | - Jean-Michel Vallat
- Centre de référence « neuropathies périphériques rares », service de Neurologie, CHU Limoges, France
| | | | - Jean-Michel Liet
- Service de réanimation pédiatrique, Hôpital Mère Enfants, Nantes, France
| | - Laure Simon
- Service de réanimation néonatale, Hôpital Mère Enfants, Nantes, France
| | - Marie Vincent
- Service de Génétique Médicale, CHU Hôtel Dieu, France
| | | | | | | | | | | | | | | | | | - Yann Péréon
- Service d'explorations fonctionnelles, CHU Hôtel Dieu, Nantes, France
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129
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Griggs RB, Yermakov LM, Susuki K. Formation and disruption of functional domains in myelinated CNS axons. Neurosci Res 2016; 116:77-87. [PMID: 27717670 DOI: 10.1016/j.neures.2016.09.010] [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: 08/31/2016] [Revised: 09/19/2016] [Accepted: 09/23/2016] [Indexed: 12/15/2022]
Abstract
Communication in the central nervous system (CNS) occurs through initiation and propagation of action potentials at excitable domains along axons. Action potentials generated at the axon initial segment (AIS) are regenerated at nodes of Ranvier through the process of saltatory conduction. Proper formation and maintenance of the molecular structure at the AIS and nodes are required for sustaining conduction fidelity. In myelinated CNS axons, paranodal junctions between the axolemma and myelinating oligodendrocytes delineate nodes of Ranvier and regulate the distribution and localization of specialized functional elements, such as voltage-gated sodium channels and mitochondria. Disruption of excitable domains and altered distribution of functional elements in CNS axons is associated with demyelinating diseases such as multiple sclerosis, and is likely a mechanism common to other neurological disorders. This review will provide a brief overview of the molecular structure of the AIS and nodes of Ranvier, as well as the distribution of mitochondria in myelinated axons. In addition, this review highlights important structural and functional changes within myelinated CNS axons that are associated with neurological dysfunction.
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Affiliation(s)
- Ryan B Griggs
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States
| | - Leonid M Yermakov
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States
| | - Keiichiro Susuki
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States.
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130
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KCC3 deficiency-induced disruption of paranodal loops and impairment of axonal excitability in the peripheral nervous system. Neuroscience 2016; 335:91-102. [DOI: 10.1016/j.neuroscience.2016.08.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 08/17/2016] [Accepted: 08/18/2016] [Indexed: 12/15/2022]
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131
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Schneider S, Gruart A, Grade S, Zhang Y, Kröger S, Kirchhoff F, Eichele G, Delgado García JM, Dimou L. Decrease in newly generated oligodendrocytes leads to motor dysfunctions and changed myelin structures that can be rescued by transplanted cells. Glia 2016; 64:2201-2218. [PMID: 27615452 DOI: 10.1002/glia.23055] [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: 06/22/2016] [Revised: 08/11/2016] [Accepted: 08/22/2016] [Indexed: 11/09/2022]
Abstract
NG2-glia in the adult brain are known to proliferate and differentiate into mature and myelinating oligodendrocytes throughout lifetime. However, the role of these newly generated oligodendrocytes in the adult brain still remains little understood. Here we took advantage of the Sox10-iCreERT2 x CAG-eGFP x Esco2fl/fl mouse line in which we can specifically ablate proliferating NG2-glia in adult animals. Surprisingly, we observed that the generation of new oligodendrocytes in the adult brain was severely affected, although the number of NG2-glia remained stable due to the enhanced proliferation of non-recombined cells. This lack of oligodendrogenesis led to the elongation of the nodes of Ranvier as well as the associated paranodes, which could be locally rescued by myelinating oligodendrocytes differentiated from transplanted NG2-glia deriving from wildtype mice. Repetitive measurements of conduction velocity in the corpus callosum of awake animals revealed a progressive deceleration specifically in the mice lacking adult oligodendrogenesis that resulted in progressive motor deficits. In summary, here we demonstrated for the first time that axon function is not only controlled by the reliable organization of myelin, but also requires a dynamic and continuous generation of new oligodendrocytes in the adult brain. GLIA 2016;64:2201-2218.
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Affiliation(s)
- Sarah Schneider
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, Germany.,Institute of Stem Cell Research, Helmholtz Zentrum, Neuherberg, Germany.,Graduate School of Systemic Neurosciences, Ludwig-Maximilians University, Munich, Germany
| | - Agnès Gruart
- División de Neurosciencias, Universidad Pablo de Olavide, Seville, Spain
| | - Sofia Grade
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, Germany.,Institute of Stem Cell Research, Helmholtz Zentrum, Neuherberg, Germany
| | - Yina Zhang
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, Germany
| | - Stephan Kröger
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center of Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Gregor Eichele
- Department of Genes and Behavior, MPI for Biophysical Chemistry, Göttingen, Germany
| | | | - Leda Dimou
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, Germany. .,Institute of Stem Cell Research, Helmholtz Zentrum, Neuherberg, Germany. .,Graduate School of Systemic Neurosciences, Ludwig-Maximilians University, Munich, Germany. .,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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132
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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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133
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Quaking Regulates Neurofascin 155 Expression for Myelin and Axoglial Junction Maintenance. J Neurosci 2016; 36:4106-20. [PMID: 27053216 DOI: 10.1523/jneurosci.3529-15.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/25/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED RNA binding proteins required for the maintenance of myelin and axoglial junctions are unknown. Herein, we report that deletion of the Quaking (QKI) RNA binding proteins in oligodendrocytes (OLs) using Olig2-Cre results in mice displaying rapid tremors at postnatal day 10, followed by death at postnatal week 3. Extensive CNS hypomyelination was observed as a result of OL differentiation defects during development. The QKI proteins were also required for adult myelin maintenance, because their ablation using PLP-CreERT resulted in hindlimb paralysis with immobility at ∼30 d after 4-hydroxytamoxifen injection. Moreover, deterioration of axoglial junctions of the spinal cord was observed and is consistent with a loss of Neurofascin 155 (Nfasc155) isoform that we confirmed as an alternative splice target of the QKI proteins. Our findings define roles for the QKI RNA binding proteins in myelin development and maintenance, as well as in the generation of Nfasc155 to maintain healthy axoglial junctions. SIGNIFICANCE STATEMENT Neurofascin 155 is responsible for axoglial junction formation and maintenance. Using a genetic mouse model to delete Quaking (QKI) RNA-binding proteins in oligodendrocytes, we identify QKI as the long-sought regulator of Neurofascin alternative splicing, further establishing the role of QKI in oligodendrocyte development and myelination. We establish a new role for QKI in myelin and axoglial junction maintenance using an inducible genetic mouse model that deletes QKI in mature oligodendrocytes. Loss of QKI in adult oligodendrocytes leads to phenotypes reminiscent of the experimental autoimmune encephalomyelitis mouse model with complete hindlimb paralysis and death by 30 d after induction of QKI deletion.
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134
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Harden N, Wang SJH, Krieger C. Making the connection – shared molecular machinery and evolutionary links underlie the formation and plasticity of occluding junctions and synapses. J Cell Sci 2016; 129:3067-76. [DOI: 10.1242/jcs.186627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
The pleated septate junction (pSJ), an ancient structure for cell–cell contact in invertebrate epithelia, has protein components that are found in three more-recent junctional structures, the neuronal synapse, the paranodal region of the myelinated axon and the vertebrate epithelial tight junction. These more-recent structures appear to have evolved through alterations of the ancestral septate junction. During its formation in the developing animal, the pSJ exhibits plasticity, although the final structure is extremely robust. Similar to the immature pSJ, the synapse and tight junctions both exhibit plasticity, and we consider evidence that this plasticity comes at least in part from the interaction of members of the immunoglobulin cell adhesion molecule superfamily with highly regulated membrane-associated guanylate kinases. This plasticity regulation probably arose in order to modulate the ancestral pSJ and is maintained in the derived structures; we suggest that it would be beneficial when studying plasticity of one of these structures to consider the literature on the others. Finally, looking beyond the junctions, we highlight parallels between epithelial and synaptic membranes, which both show a polarized distribution of many of the same proteins – evidence that determinants of apicobasal polarity in epithelia also participate in patterning of the synapse.
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Affiliation(s)
- Nicholas Harden
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
| | - Simon Ji Hau Wang
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
| | - Charles Krieger
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
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135
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Begolly S, Shrager PG, Olschowka JA, Williams JP, O'Banion MK. Fractionation Spares Mice From Radiation-Induced Reductions in Weight Gain But Does Not Prevent Late Oligodendrocyte Lineage Side Effects. Int J Radiat Oncol Biol Phys 2016; 96:449-457. [PMID: 27478169 DOI: 10.1016/j.ijrobp.2016.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 04/28/2016] [Accepted: 05/04/2016] [Indexed: 01/05/2023]
Abstract
PURPOSE To determine the late effects of fractionated versus single-dose cranial radiation on murine white matter. METHODS AND MATERIALS Mice were exposed to 0 Gy, 6 × 6 Gy, or 1 × 20 Gy cranial irradiation at 10 to 12 weeks of age. Endpoints were assessed through 18 months from exposure using immunohistochemistry, electron microscopy, and electrophysiology. RESULTS Weight gain was temporarily reduced after irradiation; greater loss was seen after single versus fractionated doses. Oligodendrocyte progenitor cells were reduced early and late after both single and fractionated irradiation. Both protocols also increased myelin g-ratio, reduced the number of nodes of Ranvier, and promoted a shift in the proportion of small, unmyelinated versus large, myelinated axon fibers. CONCLUSIONS Fractionation does not adequately spare normal white matter from late radiation side effects.
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Affiliation(s)
- Sage Begolly
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Peter G Shrager
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York; Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - John A Olschowka
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Jacqueline P Williams
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York; Department of Radiation Oncology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - M Kerry O'Banion
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York; Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York.
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136
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Clark KC, Josephson A, Benusa SD, Hartley RK, Baer M, Thummala S, Joslyn M, Sword BA, Elford H, Oh U, Dilsizoglu-Senol A, Lubetzki C, Davenne M, DeVries GH, Dupree JL. Compromised axon initial segment integrity in EAE is preceded by microglial reactivity and contact. Glia 2016; 64:1190-209. [PMID: 27100937 DOI: 10.1002/glia.22991] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 11/11/2022]
Abstract
Axonal pathology is a key contributor to long-term disability in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS), but the mechanisms that underlie axonal pathology in MS remain elusive. Evidence suggests that axonal pathology is a direct consequence of demyelination, as we and others have shown that the node of Ranvier disassembles following loss of myelin. In contrast to the node of Ranvier, we now show that the axon initial segment (AIS), the axonal domain responsible for action potential initiation, remains intact following cuprizone-induced cortical demyelination. Instead, we find that the AIS is disrupted in the neocortex of mice that develop experimental autoimmune encephalomyelitis (EAE) independent of local demyelination. EAE-induced mice demonstrate profound compromise of AIS integrity with a progressive disruption that corresponds to EAE clinical disease severity and duration, in addition to cortical microglial reactivity. Furthermore, treatment with the drug didox results in attenuation of AIS pathology concomitantly with microglial reversion to a less reactive state. Together, our findings suggest that inflammation, but not demyelination, disrupts AIS integrity and that therapeutic intervention may protect and reverse this pathology. GLIA 2016;64:1190-1209.
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Affiliation(s)
- Kareem C Clark
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,VCU, Neuroscience Curriculum, Richmond, Virginia
| | - Anna Josephson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Savannah D Benusa
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,VCU, Neuroscience Curriculum, Richmond, Virginia
| | - Rebecca K Hartley
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Matthew Baer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Suneel Thummala
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Martha Joslyn
- Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
| | - Brooke A Sword
- Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
| | | | - Unsong Oh
- Department of Neurology, VCU, Richmond, Virginia
| | - Aysegul Dilsizoglu-Senol
- UPMC/Univ Paris 06 UMR S 1127, Institut Du Cerveau Et De La Moelle Épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, Paris, F-75013, France
| | - Catherine Lubetzki
- UPMC/Univ Paris 06 UMR S 1127, Institut Du Cerveau Et De La Moelle Épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, Paris, F-75013, France.,AP-HP, Hôpital De La Pitié Salpêtrière, Paris, F-75013, France
| | - Marc Davenne
- UPMC/Univ Paris 06 UMR S 1127, Institut Du Cerveau Et De La Moelle Épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, Paris, F-75013, France
| | - George H DeVries
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
| | - Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
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137
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Calvo M, Richards N, Schmid AB, Barroso A, Zhu L, Ivulic D, Zhu N, Anwandter P, Bhat MA, Court FA, McMahon SB, Bennett DLH. Altered potassium channel distribution and composition in myelinated axons suppresses hyperexcitability following injury. eLife 2016; 5:e12661. [PMID: 27033551 PMCID: PMC4841771 DOI: 10.7554/elife.12661] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 03/15/2016] [Indexed: 12/25/2022] Open
Abstract
Neuropathic pain following peripheral nerve injury is associated with hyperexcitability in damaged myelinated sensory axons, which begins to normalise over time. We investigated the composition and distribution of shaker-type-potassium channels (Kv1 channels) within the nodal complex of myelinated axons following injury. At the neuroma that forms after damage, expression of Kv1.1 and 1.2 (normally localised to the juxtaparanode) was markedly decreased. In contrast Kv1.4 and 1.6, which were hardly detectable in the naïve state, showed increased expression within juxtaparanodes and paranodes following injury, both in rats and humans. Within the dorsal root (a site remote from injury) we noted a redistribution of Kv1-channels towards the paranode. Blockade of Kv1 channels with α-DTX after injury reinstated hyperexcitability of A-fibre axons and enhanced mechanosensitivity. Changes in the molecular composition and distribution of axonal Kv1 channels, therefore represents a protective mechanism to suppress the hyperexcitability of myelinated sensory axons that follows nerve injury.
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Affiliation(s)
- Margarita Calvo
- Wolfson Centre for Age-Related Diseases, Kings College London, London, United Kingdom.,Departamento de Fisiologia, Facultad de Ciencias Biologicas- Pontificia Universidad Catolica de Chile, Santiago, Chile.,Departamento de Anestesiologia, Facultad de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Natalie Richards
- Wolfson Centre for Age-Related Diseases, Kings College London, London, United Kingdom
| | - Annina B Schmid
- School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Australia.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Alejandro Barroso
- Wolfson Centre for Age-Related Diseases, Kings College London, London, United Kingdom.,Hospital Regional Universitario de Málaga. Servicio de Anestesiología, Málaga, Spain
| | - Lan Zhu
- Wolfson Centre for Age-Related Diseases, Kings College London, London, United Kingdom.,School of Allied Health Sciences, Faculty of Health and Life Sciences, De Montfort University, Leicester, United Kingdom
| | - Dinka Ivulic
- Departamento de Fisiologia, Facultad de Ciencias Biologicas- Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Ning Zhu
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Philipp Anwandter
- Departamento Ortopedia y Traumatologia, Facultad de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Manzoor A Bhat
- Department of Physiology, UT Health Science Center at San Antonio, San Antonio, United States.,School of Medicine, UT Health Science Center at San Antonio, San Antonio, United States
| | - Felipe A Court
- Center for Integrative Biology, Universidad Mayor, Santiago, Chile.,FONDAP, Geroscience Center for Brain Health and Metabolism, Santiago, Chile.,Millenium Nucleus for Regenerative Biology, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, Kings College London, London, United Kingdom
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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138
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Rash JE, Vanderpool KG, Yasumura T, Hickman J, Beatty JT, Nagy JI. KV1 channels identified in rodent myelinated axons, linked to Cx29 in innermost myelin: support for electrically active myelin in mammalian saltatory conduction. J Neurophysiol 2016; 115:1836-59. [PMID: 26763782 PMCID: PMC4869480 DOI: 10.1152/jn.01077.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/04/2016] [Indexed: 11/22/2022] Open
Abstract
Saltatory conduction in mammalian myelinated axons was thought to be well understood before recent discoveries revealed unexpected subcellular distributions and molecular identities of the K(+)-conductance pathways that provide for rapid axonal repolarization. In this study, we visualize, identify, localize, quantify, and ultrastructurally characterize axonal KV1.1/KV1.2 channels in sciatic nerves of rodents. With the use of light microscopic immunocytochemistry and freeze-fracture replica immunogold labeling electron microscopy, KV1.1/KV1.2 channels are localized to three anatomically and compositionally distinct domains in the internodal axolemmas of large myelinated axons, where they form densely packed "rosettes" of 9-nm intramembrane particles. These axolemmal KV1.1/KV1.2 rosettes are precisely aligned with and ultrastructurally coupled to connexin29 (Cx29) channels, also in matching rosettes, in the surrounding juxtaparanodal myelin collars and along the inner mesaxon. As >98% of transmembrane proteins large enough to represent ion channels in these specialized domains, ∼500,000 KV1.1/KV1.2 channels define the paired juxtaparanodal regions as exclusive membrane domains for the voltage-gated K(+)conductance that underlies rapid axonal repolarization in mammals. The 1:1 molecular linkage of KV1 channels to Cx29 channels in the apposed juxtaparanodal collars, plus their linkage to an additional 250,000-400,000 Cx29 channels along each inner mesaxon in every large-diameter myelinated axon examined, supports previously proposed K(+)conductance directly from juxtaparanodal axoplasm into juxtaparanodal myeloplasm in mammalian axons. With neither Cx29 protein nor myelin rosettes detectable in frog myelinated axons, these data showing axon-to-myelin linkage by abundant KV1/Cx29 channels in rodent axons support renewed consideration of an electrically active role for myelin in increasing both saltatory conduction velocity and maximum propagation frequency in mammalian myelinated axons.
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Affiliation(s)
- John E Rash
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado; Program in Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, Colorado; and
| | - Kimberly G Vanderpool
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Thomas Yasumura
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Jordan Hickman
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Jonathan T Beatty
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - James I Nagy
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
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139
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Manso C, Querol L, Mekaouche M, Illa I, Devaux JJ. Contactin-1 IgG4 antibodies cause paranode dismantling and conduction defects. Brain 2016; 139:1700-12. [PMID: 27017186 DOI: 10.1093/brain/aww062] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/28/2016] [Indexed: 12/20/2022] Open
Abstract
Paranodal axoglial junctions formed by the association of contactin-1, contactin-associated protein 1, and neurofascin-155, play important functions in nerve impulse propagation along myelinated axons. Autoantibodies to contactin-1 and neurofascin-155 define chronic inflammatory demyelinating polyradiculoneuropathy subsets of patients with specific clinical features. These autoantibodies are mostly of the IgG4 isotype, but their pathogenicity has not been proven. Here, we investigated the mechanisms how IgG subclasses to contactin-1 affect conduction. We show that purified anti-contactin-1 IgG1 and IgG4 bind to paranodes. To determine whether these isotypes can pass the paranodal barrier, we incubated isolated sciatic nerves with the purified antibody or performed intraneural injections. We found that IgG4 diffused into the paranodal regions in vitro or after intraneural injections. IgG4 infiltration was slow and progressive. In 24 h, IgG4 accessed the paranode borders near the nodal lumen, and completely fill the paranodal segments by 3 days. By contrast, control IgG, anti-contactin-1 IgG1, or even anti-contactin-associated-protein-2 IgG4 did not pass the paranodal barrier. To determine whether chronic exposure to these antibodies is pathogenic, we passively transferred anti-contactin-1 IgG1 and IgG4 into Lewis rats immunized with P2 peptide. IgG4 to contactin-1, but not IgG1, induced progressive clinical deteriorations combined with gait ataxia. No demyelination, axonal degeneration, or immune infiltration were observed. Instead, these animals presented a selective loss of the paranodal specialization in motor neurons characterized by the disappearance of the contactin-associated protein 1/contactin-1/neurofascin-155 complex at paranodes. Paranode destruction did not affect nodal specialization, but resulted in a moderate node lengthening. The sensory nerves and dorsal root ganglion were not affected in these animals. Electrophysiological examination further supported these results and revealed strong nerve activity loss affecting predominantly small diameter or slow conducting motor axons. These deficits partly matched with those found in patients: proximal motor involvement, gait ataxia, and a demyelinating neuropathy that showed early axonal features. The animal model thus seemed to replicate the early deteriorations in these patients and pointed out that paranodal loss in mature fibres results in conduction defects, but not conduction slowing. Our findings indicate that IgG4 directed against contactin-1 are pathogenic and are reliable biomarkers of a specific subset of chronic inflammatory demyelinating polyneuropathy patients. These antibodies appear to loosen the paranodal barrier, thereby favouring antibody progression and causing paranodal collapse.
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Affiliation(s)
- Constance Manso
- Aix-Marseille Université, CNRS, CRN2M-UMR7286, Marseille, France
| | - Luis Querol
- Neuromuscular Diseases Unit, Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Mourad Mekaouche
- Aix-Marseille Université, CNRS, CRN2M-UMR7286, Marseille, France
| | - Isabel Illa
- Neuromuscular Diseases Unit, Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Jérôme J Devaux
- Aix-Marseille Université, CNRS, CRN2M-UMR7286, Marseille, France
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140
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Takagishi Y, Katanosaka K, Mizoguchi H, Murata Y. Disrupted axon-glia interactions at the paranode in myelinated nerves cause axonal degeneration and neuronal cell death in the aged Caspr mutant mouse shambling. Neurobiol Aging 2016; 43:34-46. [PMID: 27255813 DOI: 10.1016/j.neurobiolaging.2016.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 12/16/2022]
Abstract
Emerging evidence suggests that axonal degeneration is a disease mechanism in various neurodegenerative diseases and that the paranodes at the nodes of Ranvier may be the initial site of pathogenesis. We investigated the pathophysiology of the disease process in the central and peripheral nervous systems of a Caspr mutant mouse, shambling (shm), which is affected by disrupted paranodal structures and impaired nerve conduction of myelinated nerves. The shm mice manifest a progressive neurological phenotype as mice age. We found extensive axonal degeneration and a loss of neurons in the central nervous system and peripheral nervous system in aged shm mice. Axonal alteration of myelinated nerves was defined by abnormal distribution and expression of neurofilaments and derangements in the status of phosphorylated and non/de-phosphorylated neurofilaments. Autophagy-related structures were also accumulated in degenerated axons and neurons. In conclusion, our results suggest that disrupted axon-glia interactions at the paranode cause the cytoskeletal alteration in myelinated axons leading to neuronal cell death, and the process involves detrimental autophagy and aging as factors that promote the pathogenesis.
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Affiliation(s)
- Yoshiko Takagishi
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
| | - Kimiaki Katanosaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Hiroyuki Mizoguchi
- Research Center for Next-Generation Drug Development, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Yoshiharu Murata
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
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141
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Miyata S, Taniguchi M, Koyama Y, Shimizu S, Tanaka T, Yasuno F, Yamamoto A, Iida H, Kudo T, Katayama T, Tohyama M. Association between chronic stress-induced structural abnormalities in Ranvier nodes and reduced oligodendrocyte activity in major depression. Sci Rep 2016; 6:23084. [PMID: 26976207 PMCID: PMC4791682 DOI: 10.1038/srep23084] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 02/25/2016] [Indexed: 11/09/2022] Open
Abstract
Repeated stressful events are associated with the onset of major depressive disorder (MDD). We previously showed oligodendrocyte (OL)-specific activation of the serum/glucocorticoid-regulated kinase (SGK)1 cascade, increased expression of axon-myelin adhesion molecules, and elaboration of the oligodendrocytic arbor in the corpus callosum of chronically stressed mice. In the current study, we demonstrate that the nodes and paranodes of Ranvier in the corpus callosum were narrower in these mice. Chronic stress also led to diffuse redistribution of Caspr and Kv 1.1 and decreased the activity in white matter, suggesting a link between morphological changes in OLs and inhibition of axonal activity. OL primary cultures subjected to chronic stress resulted in SGK1 activation and translocation to the nucleus, where it inhibited the transcription of metabotropic glutamate receptors (mGluRs). Furthermore, the cAMP level and membrane potential of OLs were reduced by chronic stress exposure. We showed by diffusion tensor imaging that the corpus callosum of patients with MDD exhibited reduced fractional anisotropy, reflecting compromised white matter integrity possibly caused by axonal damage. Our findings suggest that chronic stress disrupts the organization of the nodes of Ranvier by suppressing mGluR activation in OLs, and that specific white matter abnormalities are closely associated with MDD onset.
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Affiliation(s)
- Shingo Miyata
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan
| | - Manabu Taniguchi
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yoshihisa Koyama
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Shoko Shimizu
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan
| | - Takashi Tanaka
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan
| | - Fumihiko Yasuno
- Department of Psychiatry, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Akihide Yamamoto
- Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Osaka 565-8565, Japan
| | - Hidehiro Iida
- Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Osaka 565-8565, Japan
| | - Takashi Kudo
- Department of Psychiatry, Osaka University Health Care Center, Toyonaka, Osaka 560-0043, Japan.,Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Osaka 565-0871, Japan
| | - Masaya Tohyama
- Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-sayama, Osaka 589-8511, Japan.,Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Osaka 565-0871, Japan.,Osaka Prefectural Hospital Organization, Osaka 558-8558, Japan
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142
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Devaux JJ, Miura Y, Fukami Y, Inoue T, Manso C, Belghazi M, Sekiguchi K, Kokubun N, Ichikawa H, Wong AHY, Yuki N. Neurofascin-155 IgG4 in chronic inflammatory demyelinating polyneuropathy. Neurology 2016; 86:800-7. [PMID: 26843559 PMCID: PMC4793783 DOI: 10.1212/wnl.0000000000002418] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/01/2015] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE We report the clinical and serologic features of Japanese patients with chronic inflammatory demyelinating polyneuropathy (CIDP) displaying anti-neurofascin-155 (NF155) immunoglobulin G4 (IgG4) antibodies. METHODS In sera from 533 patients with CIDP, anti-NF155 IgG4 antibodies were detected by ELISA. Binding of IgG antibodies to central and peripheral nerves was tested. RESULTS Anti-NF155 IgG4 antibodies were identified in 38 patients (7%) with CIDP, but not in disease controls or normal participants. These patients were younger at onset as compared to 100 anti-NF155-negative patients with CIDP. Twenty-eight patients (74%) presented with sensory ataxia, 16 (42%) showed tremor, 5 (13%) presented with cerebellar ataxia associated with nystagmus, 3 (8%) had demyelinating lesions in the CNS, and 20 of 25 (80%) had poor response to IV immunoglobulin. The clinical features of the antibody-positive patients were statistically more frequent as compared to negative patients with CIDP (n = 100). Anti-NF155 IgG antibodies targeted similarly central and peripheral paranodes. CONCLUSION Anti-NF155 IgG4 antibodies were associated with a subgroup of patients with CIDP showing a younger age at onset, ataxia, tremor, CNS demyelination, and a poor response to IV immunoglobulin. The autoantibodies may serve as a biomarker to improve patients' diagnosis and guide treatments.
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Affiliation(s)
- Jérôme J Devaux
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Yumako Miura
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Yuki Fukami
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Takayuki Inoue
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Constance Manso
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Maya Belghazi
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Kenji Sekiguchi
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Norito Kokubun
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Hiroo Ichikawa
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Anna Hiu Yi Wong
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan
| | - Nobuhiro Yuki
- From Aix-Marseille Université (J.J.D., C.M., M.B.), CNRS, CRN2M-UMR 7286, Marseille, France; Departments of Medicine (Y.M., Y.F., T.I., A.H.Y.W., N.Y.) and Physiology (N.Y.), Yong Loo Lin School of Medicine, National University of Singapore; Brain and Mind Centre (N.Y.), University of Sydney, Australia; Division of Neurology (K.S.), Kobe University Graduate School of Medicine; Department of Neurology (N.K.), Dokkyo Medical University, Tochigi; and Department of Neurology (H.I.), Brain Nerve Center, Showa University Fujigaoka Hospital, Tokyo, Japan.
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143
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Seytanoglu A, Alsomali NI, Valori CF, McGown A, Kim HR, Ning K, Ramesh T, Sharrack B, Wood JD, Azzouz M. Deficiency in the mRNA export mediator Gle1 impairs Schwann cell development in the zebrafish embryo. Neuroscience 2016; 322:287-97. [PMID: 26921650 DOI: 10.1016/j.neuroscience.2016.02.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 02/17/2016] [Accepted: 02/17/2016] [Indexed: 12/12/2022]
Abstract
GLE1 mutations cause lethal congenital contracture syndrome 1 (LCCS1), a severe autosomal recessive fetal motor neuron disease, and more recently have been associated with amyotrophic lateral sclerosis (ALS). The gene encodes a highly conserved protein with an essential role in mRNA export. The mechanism linking Gle1 function to motor neuron degeneration in humans has not been elucidated, but increasing evidence implicates abnormal RNA processing as a key event in the pathogenesis of several motor neuron diseases. Homozygous gle1(-/-) mutant zebrafish display various aspects of LCCS, showing severe developmental abnormalities including motor neuron arborization defects and embryonic lethality. A previous gene expression study on spinal cord from LCCS fetuses indicated that oligodendrocyte dysfunction may be an important factor in LCCS. We therefore set out to investigate the development of myelinating glia in gle1(-/-) mutant zebrafish embryos. While expression of myelin basic protein (mbp) in hindbrain oligodendrocytes appeared relatively normal, our studies revealed a prominent defect in Schwann cell precursor proliferation and differentiation in the posterior lateral line nerve. Other genes mutated in LCCS have important roles in Schwann cell development, thereby suggesting that Schwann cell deficits may be a common factor in LCCS pathogenesis. These findings illustrate the potential importance of glial cells such as myelinating Schwann cells in motor neuron diseases linked to RNA processing defects.
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Affiliation(s)
- A Seytanoglu
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - N I Alsomali
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - C F Valori
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - A McGown
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - H R Kim
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - K Ning
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - T Ramesh
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - B Sharrack
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK; Department of Neurology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals Foundation Trust, Glossop Road, Sheffield S10 2JF, UK
| | - J D Wood
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK; Bateson Centre, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - M Azzouz
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK; Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
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144
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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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145
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Freeman SA, Desmazières A, Fricker D, Lubetzki C, Sol-Foulon N. Mechanisms of sodium channel clustering and its influence on axonal impulse conduction. Cell Mol Life Sci 2016; 73:723-35. [PMID: 26514731 PMCID: PMC4735253 DOI: 10.1007/s00018-015-2081-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/16/2022]
Abstract
The efficient propagation of action potentials along nervous fibers is necessary for animals to interact with the environment with timeliness and precision. Myelination of axons is an essential step to ensure fast action potential propagation by saltatory conduction, a process that requires highly concentrated voltage-gated sodium channels at the nodes of Ranvier. Recent studies suggest that the clustering of sodium channels can influence axonal impulse conduction in both myelinated and unmyelinated fibers, which could have major implications in disease, particularly demyelinating pathology. This comprehensive review summarizes the mechanisms governing the clustering of sodium channels at the peripheral and central nervous system nodes and the specific roles of their clustering in influencing action potential conduction. We further highlight the classical biophysical parameters implicated in conduction timing, followed by a detailed discussion on how sodium channel clustering along unmyelinated axons can impact axonal impulse conduction in both physiological and pathological contexts.
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Affiliation(s)
- Sean A Freeman
- ICM-GHU Pitié-Salpêtrière, Sorbonne Universités UPMC Univ Paris 06, UMR_S 1127, 75013, Paris, France.
- Inserm U1127, 75013, Paris, France.
- CNRS UMR7225, 75013, Paris, France.
| | - Anne Desmazières
- ICM-GHU Pitié-Salpêtrière, Sorbonne Universités UPMC Univ Paris 06, UMR_S 1127, 75013, Paris, France.
- Inserm U1127, 75013, Paris, France.
- CNRS UMR7225, 75013, Paris, France.
| | - Desdemona Fricker
- ICM-GHU Pitié-Salpêtrière, Sorbonne Universités UPMC Univ Paris 06, UMR_S 1127, 75013, Paris, France.
- Inserm U1127, 75013, Paris, France.
- CNRS UMR7225, 75013, Paris, France.
| | - Catherine Lubetzki
- ICM-GHU Pitié-Salpêtrière, Sorbonne Universités UPMC Univ Paris 06, UMR_S 1127, 75013, Paris, France.
- Inserm U1127, 75013, Paris, France.
- CNRS UMR7225, 75013, Paris, France.
- Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Paris, France.
| | - Nathalie Sol-Foulon
- ICM-GHU Pitié-Salpêtrière, Sorbonne Universités UPMC Univ Paris 06, UMR_S 1127, 75013, Paris, France.
- Inserm U1127, 75013, Paris, France.
- CNRS UMR7225, 75013, Paris, France.
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146
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Caspr3-Deficient Mice Exhibit Low Motor Learning during the Early Phase of the Accelerated Rotarod Task. PLoS One 2016; 11:e0147887. [PMID: 26807827 PMCID: PMC4726695 DOI: 10.1371/journal.pone.0147887] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/08/2016] [Indexed: 11/19/2022] Open
Abstract
Caspr3 (Contactin-associated protein-like 3, Cntnap3) is a neural cell adhesion molecule belonging to the Caspr family. We have recently shown that Caspr3 is expressed abundantly between the first and second postnatal weeks in the mouse basal ganglia, including the striatum, external segment of the globus pallidus, subthalamic nucleus, and substantia nigra. However, its physiological role remains largely unknown. In this study, we conducted a series of behavioral analyses on Capsr3-knockout (KO) mice and equivalent wild-type (WT) mice to investigate the role of Caspr3 in brain function. No significant differences were observed in most behavioral traits between Caspr3-KO and WT mice, but we found that Caspr3-KO mice performed poorly during the early phase of the accelerated rotarod task in which latency to falling off a rod rotating with increasing velocity was examined. In the late phase, the performance of the Caspr3-KO mice caught up to the level of WT mice, suggesting that the deletion of Caspr3 caused a delay in motor learning. We then examined changes in neural activity after training on the accelerated rotarod by conducting immunohistochemistry using antibody to c-Fos, an indirect marker for neuronal activity. Experience of the accelerated rotarod task caused increases in the number of c-Fos-positive cells in the dorsal striatum, cerebellum, and motor cortex in both Caspr3-KO and WT mice, but the number of c-Fos-positive cells was significantly lower in the dorsal striatum of Caspr3-KO mice than in that of WT mice. The expression of c-Fos in the ventral striatum of Caspr3-KO and WT mice was not altered by the training. Our findings suggest that reduced activation of neural cells in the dorsal striatum in Caspr3-KO mice leads to a decline in motor learning in the accelerated rotarod task.
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147
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Susuki K, Otani Y, Rasband MN. Submembranous cytoskeletons stabilize nodes of Ranvier. Exp Neurol 2016; 283:446-51. [PMID: 26775177 DOI: 10.1016/j.expneurol.2015.11.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/10/2015] [Accepted: 11/23/2015] [Indexed: 01/22/2023]
Abstract
Rapid action potential propagation along myelinated axons requires voltage-gated Na(+) (Nav) channel clustering at nodes of Ranvier. At paranodes flanking nodes, myelinating glial cells interact with axons to form junctions. The regions next to the paranodes called juxtaparanodes are characterized by high concentrations of voltage-gated K(+) channels. Paranodal axoglial junctions function as barriers to restrict the position of these ion channels. These specialized domains along the myelinated nerve fiber are formed by multiple molecular mechanisms including interactions between extracellular matrix, cell adhesion molecules, and cytoskeletal scaffolds. This review highlights recent findings into the roles of submembranous cytoskeletal proteins in the stabilization of molecular complexes at and near nodes. Axonal ankyrin-spectrin complexes stabilize Nav channels at nodes. Axonal protein 4.1B-spectrin complexes contribute to paranode and juxtaparanode organization. Glial ankyrins enriched at paranodes facilitate node formation. Finally, disruption of spectrins or ankyrins by genetic mutations or proteolysis is involved in the pathophysiology of various neurological or psychiatric disorders.
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Affiliation(s)
- Keiichiro Susuki
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States.
| | - Yoshinori Otani
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH, United States
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States.
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148
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Sun N, Tischfield JA, King RA, Heiman GA. Functional Evaluations of Genes Disrupted in Patients with Tourette's Disorder. Front Psychiatry 2016; 7:11. [PMID: 26903887 PMCID: PMC4746269 DOI: 10.3389/fpsyt.2016.00011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/18/2016] [Indexed: 01/04/2023] Open
Abstract
Tourette's disorder (TD) is a highly heritable neurodevelopmental disorder with complex genetic architecture and unclear neuropathology. Disruptions of particular genes have been identified in subsets of TD patients. However, none of the findings have been replicated, probably due to the complex and heterogeneous genetic architecture of TD that involves both common and rare variants. To understand the etiology of TD, functional analyses are required to characterize the molecular and cellular consequences caused by mutations in candidate genes. Such molecular and cellular alterations may converge into common biological pathways underlying the heterogeneous genetic etiology of TD patients. Herein, we review specific genes implicated in TD etiology, discuss the functions of these genes in the mammalian central nervous system and the corresponding behavioral anomalies exhibited in animal models, and importantly, review functional analyses that can be performed to evaluate the role(s) that the genetic disruptions might play in TD. Specifically, the functional assays include novel cell culture systems, genome editing techniques, bioinformatics approaches, transcriptomic analyses, and genetically modified animal models applied or developed to study genes associated with TD or with other neurodevelopmental and neuropsychiatric disorders. By describing methods used to study diseases with genetic architecture similar to TD, we hope to develop a systematic framework for investigating the etiology of TD and related disorders.
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Affiliation(s)
- Nawei Sun
- Department of Genetics, Rutgers University, Piscataway, NJ, USA; Human Genetics Institute of New Jersey, Piscataway, NJ, USA
| | - Jay A Tischfield
- Department of Genetics, Rutgers University, Piscataway, NJ, USA; Human Genetics Institute of New Jersey, Piscataway, NJ, USA
| | - Robert A King
- Child Study Center, Yale School of Medicine , New Haven, CT , USA
| | - Gary A Heiman
- Department of Genetics, Rutgers University, Piscataway, NJ, USA; Human Genetics Institute of New Jersey, Piscataway, NJ, USA
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149
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Lee JY, Biemond M, Petratos S. Axonal degeneration in multiple sclerosis: defining therapeutic targets by identifying the causes of pathology. Neurodegener Dis Manag 2015; 5:527-48. [DOI: 10.2217/nmt.15.50] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Current therapeutics in multiple sclerosis (MS) target the putative inflammation and immune attack on CNS myelin. Despite their effectiveness in blunting the relapse rate in MS patients, such therapeutics do not prevent MS disease progression. Importantly, specific clinical dilemma arises through inability to predict MS progression and thereby therapeutically target axonal injury during MS, limiting permanent disability. The current review identifies immune and neurobiological principles that govern the sequelae of axonal degeneration during MS disease progression. Defining the specific disease arbiters, inflammatory and autoimmune, oligodendrocyte dystrophy and degenerative myelin, we discuss a basis for a molecular mechanism in axons that may be targeted therapeutically, in spatial and temporal manner to limit axonal degeneration and thereby halt progression of MS.
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Affiliation(s)
- Jae Young Lee
- Department of Medicine, Central Clinical School, Monash University, Prahran VIC 3004, Australia
| | - Melissa Biemond
- Department of Medicine, Central Clinical School, Monash University, Prahran VIC 3004, Australia
| | - Steven Petratos
- Department of Medicine, Central Clinical School, Monash University, Prahran VIC 3004, Australia
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150
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Abstract
Myelin is essential for rapid and efficient action potential propagation in vertebrates. However, the molecular mechanisms regulating myelination remain incompletely characterized. For example, even before myelination begins in the PNS, Schwann cells must radially sort axons to form 1:1 associations. Schwann cells then ensheathe and wrap axons, and establish polarized, subcellular domains, including apical and basolateral domains, paranodes, and Schmidt-Lanterman incisures. Intriguingly, polarity proteins, such as Pals1/Mpp5, are highly enriched in some of these domains, suggesting that they may regulate the polarity of Schwann cells and myelination. To test this, we generated mice with Schwann cells and oligodendrocytes that lack Pals1. During early development of the PNS, Pals1-deficient mice had impaired radial sorting of axons, delayed myelination, and reduced nerve conduction velocities. Although myelination and conduction velocities eventually recovered, polyaxonal myelination remained a prominent feature of adult Pals1-deficient nerves. Despite the enrichment of Pals1 at paranodes and incisures of control mice, nodes of Ranvier and paranodes were unaffected in Pals1-deficient mice, although we measured a significant increase in the number of incisures. As in other polarized cells, we found that Pals1 interacts with Par3 and loss of Pals1 reduced levels of Par3 in Schwann cells. In the CNS, loss of Pals1 affected neither myelination nor the establishment of polarized membrane domains. These results demonstrate that Schwann cells and oligodendrocytes use distinct mechanisms to control their polarity, and that radial sorting in the PNS is a key polarization event that requires Pals1. Significance statement: This paper reveals the role of the canonical polarity protein Pals1 in radial sorting of axons by Schwann cells. Radial sorting is essential for efficient and proper myelination and is disrupted in some types of congenital muscular dystrophy.
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