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Fan S, Liu J, Chofflet N, Bailey AO, Russell WK, Zhang Z, Takahashi H, Ren G, Rudenko G. Molecular mechanism of contactin 2 homophilic interaction. Structure 2024:S0969-2126(24)00222-3. [PMID: 38968938 DOI: 10.1016/j.str.2024.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/23/2024] [Accepted: 06/10/2024] [Indexed: 07/07/2024]
Abstract
Contactin 2 (CNTN2) is a cell adhesion molecule involved in axon guidance, neuronal migration, and fasciculation. The ectodomains of CNTN1-CNTN6 are composed of six Ig domains (Ig1-Ig6) and four FN domains. Here, we show that CNTN2 forms transient homophilic interactions (KD ∼200 nM). Cryo-EM structures of full-length CNTN2 and CNTN2_Ig1-Ig6 reveal a T-shaped homodimer formed by intertwined, parallel monomers. Unexpectedly, the horseshoe-shaped Ig1-Ig4 headpieces extend their Ig2-Ig3 tips outwards on either side of the homodimer, while Ig4, Ig5, Ig6, and the FN domains form a central stalk. Cross-linking mass spectrometry and cell-based binding assays confirm the 3D assembly of the CNTN2 homodimer. The interface mediating homodimer formation differs between CNTNs, as do the homophilic versus heterophilic interaction mechanisms. The CNTN family thus encodes a versatile molecular platform that supports a very diverse portfolio of protein interactions and that can be leveraged to strategically guide neural circuit development.
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Affiliation(s)
- Shanghua Fan
- Department of Pharmacology and Toxicology; University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jianfang Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Nicolas Chofflet
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Aaron O Bailey
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Ziqi Zhang
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada; Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada; Division of Experimental Medicine, McGill University, Montreal, QC H3A 0G4, Canada.
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Gabby Rudenko
- Department of Pharmacology and Toxicology; University of Texas Medical Branch, Galveston, TX 77555, USA; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA.
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Liu SX, Villacis Calderon DG, Maxim ZL, Beeson MM, Rao R, Tran PV. Neonatal Hypoxia-Ischemia alters Brain-Derived Contactin-2-Positive Extracellular Vesicles in the Mouse Plasma. Neuroscience 2024; 545:141-147. [PMID: 38513760 DOI: 10.1016/j.neuroscience.2024.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 03/06/2024] [Accepted: 03/16/2024] [Indexed: 03/23/2024]
Abstract
Neonatal encephalopathy (NE) impairs white matter development and results in long-term neurodevelopmental deficits. Leveraging prior findings of altered neuronal proteins carried by brain-derived extracellular vesicles (EVs) that are marked by a neural-specific cell surface glycoprotein Contactin-2 (CNTN2) in NE infants, the present study aimed to determine the correlation between brain and circulating CNTN2+-EVs and whether NE alters circulating CNTN2+-EV levels in mice. Brain tissue and plasma were collected from postnatal day (P)7, 10, 11, 15 mice to determine the baseline CNTN2 correlation between these two compartments (n = 4-7/time point/sex). NE was induced in P10 pups. Brain and plasma samples were collected at 1, 3, 6, 24, and 120 h (n = 4-8/time point/sex). CNTN2 from brain tissue and plasma EVs were quantified using ELISA. ANOVA and linear regression analyses were used to evaluate changes and correlations between brain and plasma CNTN2+-EVs. In baseline experiments, CNTN2 in brain tissue and plasma EVs peaked at P10 with no sex-difference. Brain and plasma CNTN2+-EV showed a positive correlation across early postnatal ages. NE pups showed an elevated CNTN2 in brain tissue and EVs at 1 h and only in brain tissue at 24 h. NE also abolished the positive plasma-brain correlation. The findings establish a link for central CNTN2 and its release into circulation during early postnatal life. The immediate elevation and release of CNTN2 following NE highlight a potential molecular response shortly after a brain injurious event. Our findings further support the utility of circulating brain-derived EVs as a possible bioindicator of NE.
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Affiliation(s)
- Shirelle X Liu
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | | | - Zia L Maxim
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Montana M Beeson
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Raghavendra Rao
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Phu V Tran
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
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Rodríguez-Pérez LM, López-de-San-Sebastián J, de Diego I, Smith A, Roales-Buján R, Jiménez AJ, Paez-Gonzalez P. A selective defect in the glial wedge as part of the neuroepithelium disruption in hydrocephalus development in the mouse hyh model is associated with complete corpus callosum dysgenesis. Front Cell Neurosci 2024; 18:1330412. [PMID: 38450283 PMCID: PMC10915275 DOI: 10.3389/fncel.2024.1330412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/08/2024] [Indexed: 03/08/2024] Open
Abstract
Introduction Dysgenesis of the corpus callosum is present in neurodevelopmental disorders and coexists with hydrocephalus in several human congenital syndromes. The mechanisms that underlie the etiology of congenital hydrocephalus and agenesis of the corpus callosum when they coappear during neurodevelopment persist unclear. In this work, the mechanistic relationship between both disorders is investigated in the hyh mouse model for congenital hydrocephalus, which also develops agenesis of the corpus callosum. In this model, hydrocephalus is generated by a defective program in the development of neuroepithelium during its differentiation into radial glial cells. Methods In this work, the populations implicated in the development of the corpus callosum (callosal neurons, pioneering axons, glial wedge cells, subcallosal sling and indusium griseum glial cells) were studied in wild-type and hyh mutant mice. Immunohistochemistry, mRNA in situ hybridization, axonal tracing experiments, and organotypic cultures from normal and hyh mouse embryos were used. Results Our results show that the defective program in the neuroepithelium/radial glial cell development in the hyh mutant mouse selectively affects the glial wedge cells. The glial wedge cells are necessary to guide the pioneering axons as they approach the corticoseptal boundary. Our results show that the pioneering callosal axons arising from neurons in the cingulate cortex can extend projections to the interhemispheric midline in normal and hyh mice. However, pioneering axons in the hyh mutant mouse, when approaching the area corresponding to the damaged glial wedge cell population, turned toward the ipsilateral lateral ventricle. This defect occurred before the appearance of ventriculomegaly. Discussion In conclusion, the abnormal development of the ventricular zone, which appears to be inherent to the etiology of several forms of congenital hydrocephalus, can explain, in some cases, the common association between hydrocephalus and corpus callosum dysgenesis. These results imply that further studies may be needed to understand the corpus callosum dysgenesis etiology when it concurs with hydrocephalus.
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Affiliation(s)
- Luis-Manuel Rodríguez-Pérez
- Departamento de Fisiología Humana, Histología Humana, Anatomía Patológica y Educación Física y Deportiva, Universidad de Málaga, Malaga, Spain
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
| | | | - Isabel de Diego
- Departamento de Anatomía y Medicina Legal e Historia de la Ciencia, Universidad de Málaga, Malaga, Spain
| | - Aníbal Smith
- Departamento de Anatomía y Medicina Legal e Historia de la Ciencia, Universidad de Málaga, Malaga, Spain
| | - Ruth Roales-Buján
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Malaga, Spain
| | - Antonio J. Jiménez
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Malaga, Spain
| | - Patricia Paez-Gonzalez
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Malaga, Spain
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4
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Chataigner LMP, Thärichen L, Beugelink JW, Granneman JCM, Mokiem NJ, Snijder J, Förster F, Janssen BJC. Contactin 2 homophilic adhesion structure and conformational plasticity. Structure 2024; 32:60-73.e5. [PMID: 37992710 DOI: 10.1016/j.str.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/27/2023] [Accepted: 10/26/2023] [Indexed: 11/24/2023]
Abstract
The cell-surface attached glycoprotein contactin 2 is ubiquitously expressed in the nervous system and mediates homotypic cell-cell interactions to organize cell guidance, differentiation, and adhesion. Contactin 2 consists of six Ig and four fibronectin type III domains (FnIII) of which the first four Ig domains form a horseshoe structure important for homodimerization and oligomerization. Here we report the crystal structure of the six-domain contactin 2Ig1-6 and show that the Ig5-Ig6 combination is oriented away from the horseshoe with flexion in interdomain connections. Two distinct dimer states, through Ig1-Ig2 and Ig3-Ig6 interactions, together allow formation of larger oligomers. Combined size exclusion chromatography with multiangle light scattering (SEC-MALS), small-angle X-ray scattering (SAXS) and native MS analysis indicates contactin 2Ig1-6 oligomerizes in a glycan dependent manner. SAXS and negative-stain electron microscopy reveals inherent plasticity of the contactin 2 full-ectodomain. The combination of intermolecular binding sites and ectodomain plasticity explains how contactin 2 can function as a homotypic adhesion molecule in diverse intercellular environments.
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Affiliation(s)
- Lucas M P Chataigner
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Lena Thärichen
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - J Wouter Beugelink
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Joke C M Granneman
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Nadia J Mokiem
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Joost Snijder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands
| | - Bert J C Janssen
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, the Netherlands.
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Pinatel D, Pearlstein E, Bonetto G, Goutebroze L, Karagogeos D, Crepel V, Faivre-Sarrailh C. A class-specific effect of dysmyelination on the excitability of hippocampal interneurons. eLife 2023; 12:e86469. [PMID: 37843188 PMCID: PMC10617988 DOI: 10.7554/elife.86469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 10/13/2023] [Indexed: 10/17/2023] Open
Abstract
The role of myelination for axonal conduction is well-established in projection neurons but little is known about its significance in GABAergic interneurons. Myelination is discontinuous along interneuron axons and the mechanisms controlling myelin patterning and segregation of ion channels at the nodes of Ranvier have not been elucidated. Protein 4.1B is implicated in the organization of the nodes of Ranvier as a linker between paranodal and juxtaparanodal membrane proteins to the spectrin cytoskeleton. In the present study, 4.1B KO mice are used as a genetic model to analyze the functional role of myelin in Lhx6-positive parvalbumin (PV) and somatostatin (SST) neurons, two major classes of GABAergic neurons in the hippocampus. We show that 4.1B-deficiency induces disruption of juxtaparanodal K+ channel clustering and mislocalization of nodal or heminodal Na+ channels. Strikingly, 4.1B-deficiency causes loss of myelin in GABAergic axons in the hippocampus. In particular, stratum oriens SST cells display severe axonal dysmyelination and a reduced excitability. This reduced excitability is associated with a decrease in occurrence probability of small amplitude synaptic inhibitory events on pyramidal cells. In contrast, stratum pyramidale fast-spiking PV cells do not appear affected. In conclusion, our results indicate a class-specific effect of dysmyelination on the excitability of hippocampal interneurons associated with a functional alteration of inhibitory drive.
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Affiliation(s)
| | | | | | - Laurence Goutebroze
- INSERM, Institut du Fer à Moulin, Sorbonne Université, Faculté des Sciences et IngénierieParisFrance
| | - Domna Karagogeos
- Department of Basic Sciences, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, University of CreteHeraklionGreece
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Dunn PJ, Lea RA, Maksemous N, Smith RA, Sutherland HG, Haupt LM, Griffiths LR. Exonic mutations in cell-cell adhesion may contribute to CADASIL-related CSVD pathology. Hum Genet 2023; 142:1361-1373. [PMID: 37422595 PMCID: PMC10449969 DOI: 10.1007/s00439-023-02584-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/27/2023] [Indexed: 07/10/2023]
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a condition caused by mutations in NOTCH3 and results in a phenotype characterised by recurrent strokes, vascular dementia and migraines. Whilst a genetic basis for the disease is known, the molecular mechanisms underpinning the pathology of CADASIL are still yet to be determined. Studies conducted at the Genomics Research Centre (GRC) have also identified that only 15-23% of individuals clinically suspected of CADASIL have mutations in NOTCH3. Based on this, whole exome sequencing was used to identify novel genetic variants for CADASIL-like cerebral small-vessel disease (CSVD). Analysis of functionally important variants in 50 individuals was investigated using overrepresentation tests in Gene ontology software to identify biological processes that are potentially affected in this group of patients. Further investigation of the genes in these processes was completed using the TRAPD software to identify if there is an increased number (burden) of mutations that are associated with CADASIL-like pathology. Results from this study identified that cell-cell adhesion genes were positively overrepresented in the PANTHER GO-slim database. TRAPD burden testing identified n = 15 genes that had a higher number of rare (MAF < 0.001) and predicted functionally relevant (SIFT < 0.05, PolyPhen > 0.8) mutations compared to the gnomAD v2.1.1 exome control dataset. Furthermore, these results identified ARVCF, GPR17, PTPRS, and CELSR1 as novel candidate genes in CADASIL-related pathology. This study identified a novel process that may be playing a role in the vascular damage related to CADASIL-related CSVD and implicated n = 15 genes in playing a role in the disease.
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Affiliation(s)
- Paul J Dunn
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia
- Faculty of Health Sciences and Medicine, Bond University, 15 University Drive, Robina, Gold Coast, QLD, 4226, Australia
| | - Rodney A Lea
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia
| | - Neven Maksemous
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia
| | - Robert A Smith
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia
| | - Heidi G Sutherland
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia
| | - Larisa M Haupt
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Queensland University of Technology (QUT), Brisbane, Australia
- Max Planck Queensland Centre for the Materials Sciences of Extracellular Matrices, Brisbane, Australia
| | - Lyn R Griffiths
- Genomics Research Centre, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), 60 Musk Ave, Kelvin Grove, QLD, 4059, Australia.
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Dolma S, Joshi A. The Node of Ranvier as an Interface for Axo-Glial Interactions: Perturbation of Axo-Glial Interactions in Various Neurological Disorders. J Neuroimmune Pharmacol 2023; 18:215-234. [PMID: 37285016 DOI: 10.1007/s11481-023-10072-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 05/19/2023] [Indexed: 06/08/2023]
Abstract
The action potential conduction along the axon is highly dependent on the healthy interactions between the axon and myelin-producing glial cells. Myelin, which facilitates action potential, is the protective insulation around the axon formed by Schwann cells and oligodendrocytes in the peripheral (PNS) and central nervous system (CNS), respectively. Myelin is a continuous structure with intermittent gaps called nodes of Ranvier, which are the sites enriched with ion channels, transmembrane, scaffolding, and cytoskeletal proteins. Decades-long extensive research has identified a comprehensive proteome with strictly regularized localization at the node of Ranvier. Concurrently, axon-glia interactions at the node of Ranvier have gathered significant attention as the pathophysiological targets for various neurodegenerative disorders. Numerous studies have shown the alterations in the axon-glia interactions culminating in neurological diseases. In this review, we have provided an update on the molecular composition of the node of Ranvier. Further, we have discussed in detail the consequences of disruption of axon-glia interactions during the pathogenesis of various CNS and PNS disorders.
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Affiliation(s)
- Sonam Dolma
- Department of Pharmacy, Birla Institute of Technology and Sciences- Pilani, Hyderabad campus, Telangana state, India
| | - Abhijeet Joshi
- Department of Pharmacy, Birla Institute of Technology and Sciences- Pilani, Hyderabad campus, Telangana state, India.
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8
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Savvaki M, Kafetzis G, Kaplanis SI, Ktena N, Theodorakis K, Karagogeos D. Neuronal, but not glial, Contactin 2 negatively regulates axon regeneration in the injured adult optic nerve. Eur J Neurosci 2021; 53:1705-1721. [PMID: 33469963 DOI: 10.1111/ejn.15121] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/26/2020] [Accepted: 01/17/2021] [Indexed: 01/09/2023]
Abstract
Mammalian adult neurons of the central nervous system (CNS) display limited ability to regrow axons after trauma. The developmental decline in their regenerative ability has been attributed to both intrinsic and extrinsic factors, including postnatal suppression of transcription factors and non-neuronal inhibitory components, respectively. The cell adhesion molecule Contactin 2 (CNTN2) is expressed in neurons and oligodendrocytes in the CNS. Neuronal CNTN2 is highly regulated during development and plays critical roles in axon growth and guidance and neuronal migration. On the other hand, CNTN2 expressed by oligodendrocytes interferes with the myelination process, with its ablation resulting in hypomyelination. In the current study, we investigate the role of CNTN2 in neuronal survival and axon regeneration after trauma, in the murine optic nerve crush (ONC) model. We unveil distinct roles for neuronal and glial CNTN2 in regenerative responses. Surprisingly, our data show a conflicting role of neuronal and glial CNTN2 in axon regeneration. Although glial CNTN2 as well as hypomyelination are dispensable for both neuronal survival and axon regeneration following ONC, the neuronal counterpart comprises a negative regulator of regeneration. Specifically, we reveal a novel mechanism of action for neuronal CNTN2, implicating the inhibition of Akt signalling pathway. The in vitro analysis indicates a BDNF-independent mode of action and biochemical data suggest the implication of the truncated form of TrkB neurotrophin receptor. In conclusion, CNTN2 expressed in CNS neurons serves as an inhibitor of axon regeneration after trauma and its mechanism of action involves the neutralization of Akt-mediated neuroprotective effects.
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Affiliation(s)
- Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - George Kafetzis
- Department of Biology, University of Crete, Crete, Greece.,School of Life Sciences, University of Sussex, Brighton, UK
| | - Stefanos-Ioannis Kaplanis
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - Niki Ktena
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - Kostas Theodorakis
- Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete, Crete, Greece.,Institute of Molecular Biology & Biotechnology - FoRTH, Heraklion, Crete, Greece
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Kalafatakis I, Savvaki M, Velona T, Karagogeos D. Implication of Contactins in Demyelinating Pathologies. Life (Basel) 2021; 11:life11010051. [PMID: 33451101 PMCID: PMC7828632 DOI: 10.3390/life11010051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/09/2021] [Accepted: 01/11/2021] [Indexed: 12/19/2022] Open
Abstract
Demyelinating pathologies comprise of a variety of conditions where either central or peripheral myelin is attacked, resulting in white matter lesions and neurodegeneration. Myelinated axons are organized into molecularly distinct domains, and this segregation is crucial for their proper function. These defined domains are differentially affected at the different stages of demyelination as well as at the lesion and perilesion sites. Among the main players in myelinated axon organization are proteins of the contactin (CNTN) group of the immunoglobulin superfamily (IgSF) of cell adhesion molecules, namely Contactin-1 and Contactin-2 (CNTN1, CNTN2). The two contactins perform their functions through intermolecular interactions, which are crucial for myelinated axon integrity and functionality. In this review, we focus on the implication of these two molecules as well as their interactors in demyelinating pathologies in humans. At first, we describe the organization and function of myelinated axons in the central (CNS) and the peripheral (PNS) nervous system, further analyzing the role of CNTN1 and CNTN2 as well as their interactors in myelination. In the last section, studies showing the correlation of the two contactins with demyelinating pathologies are reviewed, highlighting the importance of these recognition molecules in shaping the function of the nervous system in multiple ways.
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10
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Suter TACS, Blagburn SV, Fisher SE, Anderson-Keightly HM, D'Elia KP, Jaworski A. TAG-1 Multifunctionality Coordinates Neuronal Migration, Axon Guidance, and Fasciculation. Cell Rep 2020; 30:1164-1177.e7. [PMID: 31995756 PMCID: PMC7049094 DOI: 10.1016/j.celrep.2019.12.085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 10/25/2019] [Accepted: 12/22/2019] [Indexed: 11/03/2022] Open
Abstract
Neuronal migration, axon fasciculation, and axon guidance need to be closely coordinated for neural circuit assembly. Spinal motor neurons (MNs) face unique challenges during development because their cell bodies reside within the central nervous system (CNS) and their axons project to various targets in the body periphery. The molecular mechanisms that contain MN somata within the spinal cord while allowing their axons to exit the CNS and navigate to their final destinations remain incompletely understood. We find that the MN cell surface protein TAG-1 anchors MN cell bodies in the spinal cord to prevent their emigration, mediates motor axon fasciculation during CNS exit, and guides motor axons past dorsal root ganglia. TAG-1 executes these varied functions in MN development independently of one another. Our results identify TAG-1 as a key multifunctional regulator of MN wiring that coordinates neuronal migration, axon fasciculation, and axon guidance. Suter et al. demonstrate that the motor neuron cell surface molecule TAG-1 confines motor neurons to the central nervous system, promotes motor axon fasciculation, and steers motor axons past inappropriate targets. This study highlights how a single cell adhesion molecule coordinates multiple steps in neuronal wiring through partially divergent mechanisms.
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Affiliation(s)
- Tracey A C S Suter
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Sara V Blagburn
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | - Sophie E Fisher
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA
| | | | - Kristen P D'Elia
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Department of Biology, Providence College, Providence, RI 02918, USA
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Robert J. and Nancy D. Carney Institute for Brain Science, Providence, RI 02912, USA.
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Alcover-Sanchez B, Garcia-Martin G, Escudero-Ramirez J, Gonzalez-Riano C, Lorenzo P, Gimenez-Cassina A, Formentini L, de la Villa-Polo P, Pereira MP, Wandosell F, Cubelos B. Absence of R-Ras1 and R-Ras2 causes mitochondrial alterations that trigger axonal degeneration in a hypomyelinating disease model. Glia 2020; 69:619-637. [PMID: 33010069 DOI: 10.1002/glia.23917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Fast synaptic transmission in vertebrates is critically dependent on myelin for insulation and metabolic support. Myelin is produced by oligodendrocytes (OLs) that maintain multilayered membrane compartments that wrap around axonal fibers. Alterations in myelination can therefore lead to severe pathologies such as multiple sclerosis. Given that hypomyelination disorders have complex etiologies, reproducing clinical symptoms of myelin diseases from a neurological perspective in animal models has been difficult. We recently reported that R-Ras1-/- and/or R-Ras2-/- mice, which lack GTPases essential for OL survival and differentiation processes, present different degrees of hypomyelination in the central nervous system with a compounded hypomyelination in double knockout (DKO) mice. Here, we discovered that the loss of R-Ras1 and/or R-Ras2 function is associated with aberrant myelinated axons with increased numbers of mitochondria, and a disrupted mitochondrial respiration that leads to increased reactive oxygen species levels. Consequently, aberrant myelinated axons are thinner with cytoskeletal phosphorylation patterns typical of axonal degeneration processes, characteristic of myelin diseases. Although we observed different levels of hypomyelination in a single mutant mouse, the combined loss of function in DKO mice lead to a compromised axonal integrity, triggering the loss of visual function. Our findings demonstrate that the loss of R-Ras function reproduces several characteristics of hypomyelinating diseases, and we therefore propose that R-Ras1-/- and R-Ras2-/- neurological models are valuable approaches for the study of these myelin pathologies.
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Affiliation(s)
- Berta Alcover-Sanchez
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Gonzalo Garcia-Martin
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Juan Escudero-Ramirez
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carolina Gonzalez-Riano
- CEMBIO (Centre for Metabolomics and Bioanalysis), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Paz Lorenzo
- CEMBIO (Centre for Metabolomics and Bioanalysis), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Alfredo Gimenez-Cassina
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Laura Formentini
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Pedro de la Villa-Polo
- Departamento de Biología de Sistemas, Universidad de Alcalá, Madrid, Spain.,Grupo de Neurofisiología Visual, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Marta P Pereira
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Francisco Wandosell
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Beatriz Cubelos
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
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12
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Mechanisms of axon polarization in pyramidal neurons. Mol Cell Neurosci 2020; 107:103522. [PMID: 32653476 DOI: 10.1016/j.mcn.2020.103522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 06/19/2020] [Accepted: 06/29/2020] [Indexed: 01/19/2023] Open
Abstract
Neurons are highly polarized cells that have specialized regions for synaptic input, the dendrites, and synaptic output, the axons. This polarity is critical for appropriate neural circuit formation and function. One of the central gaps in our knowledge is understanding how developing neurons initiate axon polarity. Given the critical nature of this polarity on neural circuit formation and function, neurons have evolved multiple mechanisms comprised of extracellular and intracellular cues that allow them to initiate and form axons. These mechanisms engage a variety of signaling cascades that provide positive and negative cues to ensure axon polarization. This review highlights our current knowledge of the molecular underpinnings of axon polarization in pyramidal neurons and their relevance to the development of the brain.
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13
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Kalafatakis I, Kalafatakis K, Tsimpolis A, Giannakeas N, Tsipouras M, Tzallas A, Karagogeos D. Using the Allen gene expression atlas of the adult mouse brain to gain further insight into the physiological significance of TAG-1/Contactin-2. Brain Struct Funct 2020; 225:2045-2056. [PMID: 32601750 DOI: 10.1007/s00429-020-02108-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 06/21/2020] [Indexed: 12/11/2022]
Abstract
The anatomic gene expression atlas (AGEA) of the adult mouse brain of the Allen Institute for Brain Science is a transcriptome-based atlas of the adult C57Bl/6 J mouse brain, based on the extensive in situ hybridization dataset of the Institute. This spatial mapping of the gene expression levels of mice under baseline conditions could assist in the formation of new, reasonable transcriptome-derived hypotheses on brain structure and underlying biochemistry, which could also have functional implications. The aim of this work is to use the data of the AGEA (in combination with Tabula Muris, a compendium of single cell transcriptome data collected from mice, enabling direct and controlled comparison of gene expression among cell types) to provide further insights into the physiology of TAG-1/Contactin-2 and its interactions, by presenting the expression of the corresponding gene across the adult mouse brain under baseline conditions and to investigate any spatial genomic correlations between TAG-1/Contactin-2 and its interacting proteins and markers of mature and immature oligodendrocytes, based on the pre-existing experimental or bibliographical evidence. The across-brain correlation analysis on the gene expression intensities showed a positive spatial correlation of TAG-1/Contactin-2 with the gene expression of Plp1, Myrf, Mbp, Mog, Cldn11, Bace1, Kcna1, Kcna2, App and Nfasc and a negative spatial correlation with the gene expression of Cspg4, Pdgfra, L1cam, Ncam1, Ncam2 and Ptprz1. Spatially correlated genes are mainly expressed by mature oligodendrocytes (like Cntn2), while spatially anticorrelated genes are mainly expressed by oligodendrocyte precursor cells. According to the data presented in this work, we propose that even though Contactin-2 expression during development correlates with high plasticity events, such as neuritogenesis, in adulthood it correlates with pathways characterized by low plasticity.
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Affiliation(s)
- Ilias Kalafatakis
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece.
| | - Konstantinos Kalafatakis
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Alexandros Tsimpolis
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece
| | - Nikos Giannakeas
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Markos Tsipouras
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Alexandros Tzallas
- Department of Informatics and Telecommunications, School of Informatics and Telecommunications, University of Ioannina, Arta, Greece
| | - Domna Karagogeos
- Faculty of Medicine, University of Crete & Institute of Molecular Biology and Biotechnology, Foundation of Research and Technology Hellas, Heraklion, Crete, Greece
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Michael S, Waters P, Irani SR. Stop testing for autoantibodies to the VGKC-complex: only request LGI1 and CASPR2. Pract Neurol 2020; 20:377-384. [DOI: 10.1136/practneurol-2019-002494] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 04/16/2020] [Accepted: 04/30/2020] [Indexed: 12/16/2022]
Abstract
Autoantibodies to leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein like-2 (CASPR2) are associated with clinically distinctive syndromes that are highly immunotherapy responsive, such as limbic encephalitis, faciobrachial dystonic seizures, Morvan’s syndrome and neuromyotonia. These autoantibodies target surface-exposed domains of LGI1 or CASPR2, and appear to be directly pathogenic. In contrast, voltage-gated potassium channel (VGKC) antibodies that lack LGI1 or CASPR2 reactivities (‘double-negative’) are common in healthy controls and have no consistent associations with distinct syndromes. These antibodies target intracellular epitopes and lack pathogenic potential. Moreover, the clinically important LGI1 and CASPR2 antibodies comprise only ~15% of VGKC-positive results, meaning that most VGKC-antibody positive results mislead rather than help. Further, initial VGKC testing misses some cases that have LGI1 and CASPR2 antibodies. These collective observations confirm that laboratories should stop testing for VGKC antibodies and instead, test only for LGI1 and CASPR2 antibodies. This change in practice will lead to significant patient benefit.
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15
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The Interaction Between Contactin and Amyloid Precursor Protein and Its Role in Alzheimer’s Disease. Neuroscience 2020; 424:184-202. [DOI: 10.1016/j.neuroscience.2019.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 01/06/2023]
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16
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Bonetto G, Hivert B, Goutebroze L, Karagogeos D, Crépel V, Faivre-Sarrailh C. Selective Axonal Expression of the Kv1 Channel Complex in Pre-myelinated GABAergic Hippocampal Neurons. Front Cell Neurosci 2019; 13:222. [PMID: 31164806 PMCID: PMC6535494 DOI: 10.3389/fncel.2019.00222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/02/2019] [Indexed: 01/01/2023] Open
Abstract
In myelinated fibers, the voltage-gated sodium channels Nav1 are concentrated at the nodal gap to ensure the saltatory propagation of action potentials. The voltage-gated potassium channels Kv1 are segregated at the juxtaparanodes under the compact myelin sheath and may stabilize axonal conduction. It has been recently reported that hippocampal GABAergic neurons display high density of Nav1 channels remarkably in clusters along the axon before myelination (Freeman et al., 2015). In inhibitory neurons, the Nav1 channels are trapped by the ankyrinG scaffold at the axon initial segment (AIS) as observed in pyramidal and granule neurons, but are also forming “pre-nodes,” which may accelerate conduction velocity in pre-myelinated axons. However, the distribution of the Kv1 channels along the pre-myelinated inhibitory axons is still unknown. In the present study, we show that two subtypes of hippocampal GABAergic neurons, namely the somatostatin and parvalbumin positive cells, display a selective high expression of Kv1 channels at the AIS and all along the unmyelinated axons. These inhibitory axons are also highly enriched in molecules belonging to the juxtaparanodal Kv1 complex, including the cell adhesion molecules (CAMs) TAG-1, Caspr2, and ADAM22 and the scaffolding protein 4.1B. Here, taking advantage of hippocampal cultures from 4.1B and TAG-1 knock-out mice, we observed that 4.1B is required for the proper positioning of Caspr2 and TAG-1 along the distal axon, and that TAG-1 deficiency induces alterations in the axonal distribution of Caspr2. However, the axonal expression of Kv1 channels and clustering of ankyrinG were not modified. In conclusion, this study allowed the analysis of the hierarchy between channels, CAMs and scaffolding proteins for their expression along hippocampal inhibitory axons before myelination. The early steps of channel compartmentalization preceding myelination may be crucial for stabilizing nerve impulses switching from a continuous to saltatory conduction during network development.
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Affiliation(s)
- Giulia Bonetto
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
| | - Bruno Hivert
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
| | - Laurence Goutebroze
- INSERM UMR-S 1270, Institut du Fer à Moulin, Faculté des Sciences et Ingénierie, Sorbonne Université, Paris, France
| | - Domna Karagogeos
- Department of Basic Sciences, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, University of Crete Medical School - University of Crete, Heraklion, Greece
| | - Valérie Crépel
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
| | - Catherine Faivre-Sarrailh
- INSERM UMR1249, Institut de Neurobiologie de la Méditerranée, Aix-Marseille Université, Marseille, France
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Chatterjee M, Schild D, Teunissen CE. Contactins in the central nervous system: role in health and disease. Neural Regen Res 2019; 14:206-216. [PMID: 30530999 PMCID: PMC6301169 DOI: 10.4103/1673-5374.244776] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/17/2018] [Indexed: 01/06/2023] Open
Abstract
Contactins are a group of cell adhesion molecules that are mainly expressed in the brain and play pivotal roles in the organization of axonal domains, axonal guidance, neuritogenesis, neuronal development, synapse formation and plasticity, axo-glia interactions and neural regeneration. Contactins comprise a family of six members. Their absence leads to malformed axons and impaired nerve conduction. Contactin mediated protein complex formation is critical for the organization of the axon in early central nervous system development. Mutations and differential expression of contactins have been identified in neuro-developmental or neurological disorders. Taken together, contactins are extensively studied in the context of nervous system development. This review summarizes the physiological roles of all six members of the Contactin family in neurodevelopment as well as their involvement in neurological/neurodevelopmental disorders.
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Affiliation(s)
- Madhurima Chatterjee
- Amsterdam UMC, VU University Medical Center, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Göttingen, Germany
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany
- DFG Excellence Cluster 171, University of Göttingen, Göttingen, Germany
| | - Charlotte E. Teunissen
- Amsterdam UMC, VU University Medical Center, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam, The Netherlands
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18
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Segklia K, Stamatakis A, Stylianopoulou F, Lavdas AA, Matsas R. Increased Anxiety-Related Behavior, Impaired Cognitive Function and Cellular Alterations in the Brain of Cend1-deficient Mice. Front Cell Neurosci 2019; 12:497. [PMID: 30760981 PMCID: PMC6361865 DOI: 10.3389/fncel.2018.00497] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 12/03/2018] [Indexed: 01/09/2023] Open
Abstract
Cend1 is a neuronal-lineage specific modulator involved in coordination of cell cycle exit and differentiation of neuronal precursors. We have previously shown that Cend1-/- mice show altered cerebellar layering caused by increased proliferation of granule cell precursors, delayed radial granule cell migration and compromised Purkinje cell differentiation, leading to ataxic gait and deficits in motor coordination. To further characterize the effects of Cend1 genetic ablation we determined herein a range of behaviors, including anxiety and exploratory behavior in the elevated plus maze (EPM), associative learning in fear conditioning, and spatial learning and memory in the Morris water maze (MWM). We observed significant deficits in all tests, suggesting structural and/or functional alterations in brain regions such as the cortex, amygdala and the hippocampus. In agreement with these findings, immunohistochemistry revealed reduced numbers of γ amino butyric acid (GABA) GABAergic interneurons, but not of glutamatergic projection neurons, in the adult cerebral cortex. Reduced GABAergic interneurons were also observed in the amygdala, most notably in the basolateral nucleus. The paucity in GABAergic interneurons in adult Cend1-/- mice correlated with increased proliferation and apoptosis as well as reduced migration of neuronal progenitors from the embryonic medial ganglionic eminence (MGE), the origin of these cells. Further we noted reduced GABAergic neurons and aberrant neurogenesis in the adult dentate gyrus (DG) of the hippocampus, which has been previously shown to confer spatial learning and memory deficits. Our data highlight the necessity of Cend1 expression in the formation of a structurally and functionally normal brain phenotype.
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Affiliation(s)
- Katerina Segklia
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Antonios Stamatakis
- Biology-Biochemistry Lab, Faculty of Nursing, School of Health Sciences, National and Kapodistrian University of Athens, Athens, Greece
| | - Fotini Stylianopoulou
- Biology-Biochemistry Lab, Faculty of Nursing, School of Health Sciences, National and Kapodistrian University of Athens, Athens, Greece
| | - Alexandros A Lavdas
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Rebecca Matsas
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
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Gurung S, Asante E, Hummel D, Williams A, Feldman-Schultz O, Halloran MC, Sittaramane V, Chandrasekhar A. Distinct roles for the cell adhesion molecule Contactin2 in the development and function of neural circuits in zebrafish. Mech Dev 2018; 152:1-12. [PMID: 29777776 DOI: 10.1016/j.mod.2018.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/02/2018] [Accepted: 05/09/2018] [Indexed: 01/17/2023]
Abstract
Contactin2 (Cntn2)/Transient Axonal Glycoprotein 1 (Tag1), a neural cell adhesion molecule, has established roles in neuronal migration and axon fasciculation in chick and mouse. In zebrafish, antisense morpholino-based studies have indicated roles for cntn2 in the migration of facial branchiomotor (FBM) neurons, the guidance of the axons of the nucleus of the medial longitudinal fascicle (nucMLF), and the outgrowth of Rohon-Beard (RB) central axons. To study functions of Cntn2 in later stages of neuronal development, we generated cntn2 mutant zebrafish using CRISPR-Cas9. Using a null mutant allele, we detected genetic interactions between cntn2 and the planar cell polarity gene vangl2, as shown previously with cntn2 morphants, demonstrating a function for cntn2 during FBM neuron migration in a sensitized background of reduced planar cell polarity signaling. In addition, maternal-zygotic (MZ) cntn2 mutant larvae exhibited aberrant touch responses and swimming, suggestive of defects in sensorimotor circuits, consistent with studies in mice. However, the nucMLF axon convergence, FBM neuron migration, and RB outgrowth defects seen in morphants were not seen in the mutants, and we show here that they are likely off-target effects of morpholinos. However, MLF axons exhibited local defasciculation in MZcntn2 mutants, consistent with a role for Cntn2 in axon fasciculation. These data demonstrate distinct roles for zebrafish cntn2 in neuronal migration and axon fasciculation, and in the function of sensorimotor circuits.
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Affiliation(s)
- Suman Gurung
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Emilia Asante
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Devynn Hummel
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Ashley Williams
- Department of Biology, Georgia Southern University, Statesboro, GA 30458, USA
| | - Oren Feldman-Schultz
- Department of Integrative Biology, Department of Neuroscience, University of Wisconsin, Madison, WI 53706, USA
| | - Mary C Halloran
- Department of Integrative Biology, Department of Neuroscience, University of Wisconsin, Madison, WI 53706, USA
| | - Vinoth Sittaramane
- Department of Biology, Georgia Southern University, Statesboro, GA 30458, USA
| | - Anand Chandrasekhar
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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20
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R-Ras1 and R-Ras2 Are Essential for Oligodendrocyte Differentiation and Survival for Correct Myelination in the Central Nervous System. J Neurosci 2018; 38:5096-5110. [PMID: 29720552 DOI: 10.1523/jneurosci.3364-17.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/14/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022] Open
Abstract
Rapid and effective neural transmission of information requires correct axonal myelination. Modifications in myelination alter axonal capacity to transmit electric impulses and enable pathological conditions. In the CNS, oligodendrocytes (OLs) myelinate axons, a complex process involving various cellular interactions. However, we know little about the mechanisms that orchestrate correct myelination. Here, we demonstrate that OLs express R-Ras1 and R-Ras2. Using female and male mutant mice to delete these proteins, we found that activation of the PI3K/Akt and Erk1/2-MAPK pathways was weaker in mice lacking one or both of these GTPases, suggesting that both proteins coordinate the activity of these two pathways. Loss of R-Ras1 and/or R-Ras2 diminishes the number of OLs in major myelinated CNS tracts and increases the proportion of immature OLs. In R-Ras1-/- and R-Ras2-/--null mice, OLs show aberrant morphologies and fail to differentiate correctly into myelin-forming phenotypes. The smaller OL population and abnormal OL maturation induce severe hypomyelination, with shorter nodes of Ranvier in R-Ras1-/- and/or R-Ras2-/- mice. These defects explain the slower conduction velocity of myelinated axons that we observed in the absence of R-Ras1 and R-Ras2. Together, these results suggest that R-Ras1 and R-Ras2 are upstream elements that regulate the survival and differentiation of progenitors into OLs through the PI3K/Akt and Erk1/2-MAPK pathways for proper myelination.SIGNIFICANCE STATEMENT In this study, we show that R-Ras1 and R-Ras2 play essential roles in regulating myelination in vivo and control fundamental aspects of oligodendrocyte (OL) survival and differentiation through synergistic activation of PI3K/Akt and Erk1/2-MAPK signaling. Mice lacking R-Ras1 and/or R-Ras2 show a diminished OL population with a higher proportion of immature OLs, explaining the observed hypomyelination in main CNS tracts. In vivo electrophysiology recordings demonstrate a slower conduction velocity of nerve impulses in the absence of R-Ras1 and R-Ras2. Therefore, R-Ras1 and R-Ras2 are essential for proper axonal myelination and accurate neural transmission.
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Zoupi L, Savvaki M, Kalemaki K, Kalafatakis I, Sidiropoulou K, Karagogeos D. The function of contactin-2/TAG-1 in oligodendrocytes in health and demyelinating pathology. Glia 2017; 66:576-591. [PMID: 29165835 DOI: 10.1002/glia.23266] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/09/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022]
Abstract
The oligodendrocyte maturation process and the transition from the pre-myelinating to the myelinating state are extremely important during development and in pathology. In the present study, we have investigated the role of the cell adhesion molecule CNTN2/TAG-1 on oligodendrocyte proliferation, differentiation, myelination, and function during development and under pathological conditions. With the combination of in vivo, in vitro, ultrastructural, and electrophysiological methods, we have mapped the expression of CNTN2 protein in the oligodendrocyte lineage during the different stages of myelination and its involvement on oligodendrocyte maturation, branching, myelin-gene expression, myelination, and axonal function. The cuprizone model of central nervous system demyelination was further used to assess CNTN2 in pathology. During development, CNTN2 can transiently affect the expression levels of myelin and myelin-regulating genes, while its absence results in reduced oligodendrocyte branching, hypomyelination of fiber tracts and impaired axonal conduction. In pathology, CNTN2 absence does not affect the extent of de- and remyelination. However during remyelination, a novel, CNTN2-independent mechanism is revealed that is able to recluster voltage gated potassium channels (VGKCs) resulting in the improvement of fiber conduction.
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Affiliation(s)
- Lida Zoupi
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Katerina Kalemaki
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Ilias Kalafatakis
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
| | - Kyriaki Sidiropoulou
- Neurophysiology & Behavior Laboratory, Department of Biology, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete, Voutes University Campus, GR-70013, P.O. Box 2208, Heraklion, Crete, Greece and 1Institute of Molecular Biology & Biotechnology -FoRTH, Nikolaou Plastira 100 GR-70013, Heraklion, Crete, Greece
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Abstract
Contactin-2/transiently expressed axonal surface glycoprotein-1 (TAG-1) is a cell adhesion molecule belonging to the immunoglobulin superfamily (IgSF). It has six immunoglobulin-like extracellular domains and four fibronectin III-like ones, with anchoring to the cell membrane through glycosylphosphatidyl inositol. Contactin-2/TAG-1 is expressed in specific neurons transiently on the axonal surface during the fetal period. In postnatal stages, Contactin-2/TAG-1 is expressed in cerebellar granule cells, hippocampal pyramidal cells, and the juxtaparanodal regions of myelinated nerve fibers. In the embryonic nervous system, Contactin-2/TAG-1 plays important roles in axonal elongation, axonal guidance, and cellular migration. In the postnatal nervous system, it also plays an essential role in the formation of myelinated nerve fibers. Moreover, Contactin-2/TAG-1 has been linked to autoimmune diseases of the human nervous system. Taken together, Contactin-2/TAG-1 plays a central role in a variety of functions from development to disease.
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Affiliation(s)
- Tomoyuki Masuda
- a Doctoral and Master's Programs in Kansei, Behavioral and Brain Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba , Ibaraki , Japan.,b Department of Neurology , Faculty of Medicine, University of Tsukuba , Ibaraki , Japan.,c Department of Neurobiology , Faculty of Medicine, University of Tsukuba , Ibaraki , Japan
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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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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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Bastakis GG, Savvaki M, Stamatakis A, Vidaki M, Karagogeos D. Tag1 deficiency results in olfactory dysfunction through impaired migration of mitral cells. Development 2015; 142:4318-28. [PMID: 26525675 DOI: 10.1242/dev.123943] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 10/22/2015] [Indexed: 01/01/2023]
Abstract
The olfactory system provides mammals with the abilities to investigate, communicate and interact with their environment. These functions are achieved through a finely organized circuit starting from the nasal cavity, passing through the olfactory bulb and ending in various cortical areas. We show that the absence of transient axonal glycoprotein-1 (Tag1)/contactin-2 (Cntn2) in mice results in a significant and selective defect in the number of the main projection neurons in the olfactory bulb, namely the mitral cells. A subpopulation of these projection neurons is reduced in Tag1-deficient mice as a result of impaired migration. We demonstrate that the detected alterations in the number of mitral cells are well correlated with diminished odor discrimination ability and social long-term memory formation. Reduced neuronal activation in the olfactory bulb and the corresponding olfactory cortex suggest that Tag1 is crucial for the olfactory circuit formation in mice. Our results underpin the significance of a numerical defect in the mitral cell layer in the processing and integration of odorant information and subsequently in animal behavior.
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Affiliation(s)
- George G Bastakis
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
| | - Maria Savvaki
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
| | - Antonis Stamatakis
- Laboratory of Biology, Faculty of Nursing, School of Health Sciences, University of Athens, Papadiamantopoulou 123, Athens GR11527, Greece
| | - Marina Vidaki
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
| | - Domna Karagogeos
- Department of Basic Science, Faculty of Medicine, University of Crete and Institute of Molecular Biology and Biotechnology-FoRTH, Vassilika Vouton, Heraklion, Crete 71110, Greece
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Kastriti ME, Sargiannidou I, Kleopa KA, Karagogeos D. Differential modulation of the juxtaparanodal complex in Multiple Sclerosis. Mol Cell Neurosci 2015; 67:93-103. [DOI: 10.1016/j.mcn.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/25/2015] [Accepted: 06/08/2015] [Indexed: 12/23/2022] Open
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Chang RYK, Etheridge N, Nouwens AS, Dodd PR. SWATH analysis of the synaptic proteome in Alzheimer's disease. Neurochem Int 2015; 87:1-12. [PMID: 25958317 DOI: 10.1016/j.neuint.2015.04.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 10/23/2022]
Abstract
Brain tissue from Alzheimer's disease patients exhibits synaptic degeneration in selected regions. Synaptic dysfunction occurs early in the disease and is a primary pathological target for treatment. The molecular mechanisms underlying this degeneration remain unknown. Quantifying the synaptic proteome in autopsy brain and comparing tissue from Alzheimer's disease cases and subjects with normal aging are critical to understanding the molecular mechanisms associated with Alzheimer pathology. We isolated synaptosomes from hippocampus and motor cortex so as to reduce sample complexity relative to whole-tissue homogenates. Synaptosomal extracts were subjected to strong cation exchange (SCX) fractionation to further partition sample complexity; each fraction received SWATH-based information-dependent acquisition to generate a comprehensive peptide-ion library. The expression of synaptic proteins from AD hippocampus and motor cortex was then compared between groups. A total of 2077 unique proteins were identified at a critical local false discovery rate <5%. Thirty of these, including 17 novel proteins, exhibited significant expression differences between cases and controls; these proteins are involved in cellular functions including structural maintenance, signal transduction, autophagy, oxidative stress, and proteasome activity, or they have synaptic-vesicle related or energy-related functions. Differentially expressed proteins were subjected to pathway analysis to identify protein-protein interactions. This revealed that the most perturbed molecular and cellular functions were cellular assembly and organization. Core analysis revealed RhoA signaling to be the top canonical pathway. Network analysis showed that differentially expressed proteins were related to cellular assembly and organization, and cellular function and maintenance. This is the first study to combine SCX fractionation with SWATH analysis. SWATH is a promising new technique that can greatly enhance protein identification in any proteome, and has many other benefits; however, there are limitations yet to be resolved.
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Affiliation(s)
| | - Naomi Etheridge
- School of Chemistry and Molecular Biosciences, University of Queensland, Australia
| | - Amanda S Nouwens
- School of Chemistry and Molecular Biosciences, University of Queensland, Australia
| | - Peter R Dodd
- School of Chemistry and Molecular Biosciences, University of Queensland, Australia.
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Murcia-Belmonte V, Esteban PF, Martínez-Hernández J, Gruart A, Luján R, Delgado-García JM, de Castro F. Anosmin-1 over-expression regulates oligodendrocyte precursor cell proliferation, migration and myelin sheath thickness. Brain Struct Funct 2015; 221:1365-85. [PMID: 25662897 DOI: 10.1007/s00429-014-0977-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 12/22/2014] [Indexed: 12/11/2022]
Abstract
During development of the central nervous system, anosmin-1 (A1) works as a chemotropic cue contributing to axonal outgrowth and collateralization, as well as modulating the migration of different cell types, fibroblast growth factor receptor 1 (FGFR1) being the main receptor involved in all these events. To further understand the role of A1 during development, we have analysed the over-expression of human A1 in a transgenic mouse line. Compared with control mice during development and in early adulthood, A1 over-expressing transgenic mice showed an enhanced oligodendrocyte precursor cell (OPC) proliferation and a higher number of OPCs in the subventricular zone and in the corpus callosum (CC). The migratory capacity of OPCs from the transgenic mice is increased in vitro due to a higher basal activation of ERK1/2 mediated through FGFR1 and they also produced more myelin basic protein (MBP). In vivo, the over-expression of A1 resulted in an elevated number of mature oligodendrocytes with higher levels of MBP mRNA and protein, as well as increased levels of activation of the ERK1/2 proteins, while electron microscopy revealed thicker myelin sheaths around the axons of the CC in adulthood. Also in the mature CC, the nodes of Ranvier were significantly longer and the conduction velocity of the nerve impulse in vivo was significantly increased in the CC of A1 over-expressing transgenic mice. Altogether, these data confirmed the involvement of A1 in oligodendrogliogenesis and its relevance for myelination.
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Affiliation(s)
- Verónica Murcia-Belmonte
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos, Finca La Peraleda, s/n, 45071, Toledo, Spain.,Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Campus San Juan de Alicante, 03550, Alicante, Spain
| | - Pedro F Esteban
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos, Finca La Peraleda, s/n, 45071, Toledo, Spain
| | - José Martínez-Hernández
- Departamento de Ciencias Médicas, CRIB-Facultad de Medicina, Universidad de Castilla-La Mancha, C/Almansa 14, 02006, Albacete, Spain
| | - Agnès Gruart
- División de Neurociencias, Universidad Pablo de Olavide, Ctra. De Utrera, Km.1, 41013, Seville, Spain
| | - Rafael Luján
- Departamento de Ciencias Médicas, CRIB-Facultad de Medicina, Universidad de Castilla-La Mancha, C/Almansa 14, 02006, Albacete, Spain
| | - José María Delgado-García
- División de Neurociencias, Universidad Pablo de Olavide, Ctra. De Utrera, Km.1, 41013, Seville, Spain
| | - Fernando de Castro
- Grupo de Neurobiología del Desarrollo-GNDe, Hospital Nacional de Parapléjicos, Finca La Peraleda, s/n, 45071, Toledo, Spain.
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The node of Ranvier in CNS pathology. Acta Neuropathol 2014; 128:161-75. [PMID: 24913350 PMCID: PMC4102831 DOI: 10.1007/s00401-014-1305-z] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/27/2014] [Accepted: 05/27/2014] [Indexed: 12/11/2022]
Abstract
Healthy nodes of Ranvier are crucial for action potential propagation along myelinated axons, both in the central and in the peripheral nervous system. Surprisingly, the node of Ranvier has often been neglected when describing CNS disorders, with most pathologies classified simply as being due to neuronal defects in the grey matter or due to oligodendrocyte damage in the white matter. However, recent studies have highlighted changes that occur in pathological conditions at the node of Ranvier, and at the associated paranodal and juxtaparanodal regions where neurons and myelinating glial cells interact. Lengthening of the node of Ranvier, failure of the electrically resistive seal between the myelin and the axon at the paranode, and retraction of myelin to expose voltage-gated K+ channels in the juxtaparanode, may contribute to altering the function of myelinated axons in a wide range of diseases, including stroke, spinal cord injury and multiple sclerosis. Here, we review the principles by which the node of Ranvier operates and its molecular structure, and thus explain how defects at the node and paranode contribute to neurological disorders.
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30
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Vassar R, Kuhn PH, Haass C, Kennedy ME, Rajendran L, Wong PC, Lichtenthaler SF. Function, therapeutic potential and cell biology of BACE proteases: current status and future prospects. J Neurochem 2014; 130:4-28. [PMID: 24646365 PMCID: PMC4086641 DOI: 10.1111/jnc.12715] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 01/18/2023]
Abstract
The β-site APP cleaving enzymes 1 and 2 (BACE1 and BACE2) were initially identified as transmembrane aspartyl proteases cleaving the amyloid precursor protein (APP). BACE1 is a major drug target for Alzheimer's disease because BACE1-mediated cleavage of APP is the first step in the generation of the pathogenic amyloid-β peptides. BACE1, which is highly expressed in the nervous system, is also required for myelination by cleaving neuregulin 1. Several recent proteomic and in vivo studies using BACE1- and BACE2-deficient mice demonstrate a much wider range of physiological substrates and functions for both proteases within and outside of the nervous system. For BACE1 this includes axon guidance, neurogenesis, muscle spindle formation, and neuronal network functions, whereas BACE2 was shown to be involved in pigmentation and pancreatic β-cell function. This review highlights the recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer's disease. The protease BACE1 is a major drug target in Alzheimer disease. Together with its homolog BACE2, both proteases have an increasing number of functions within and outside of the nervous system. This review highlights recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer disease.
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Affiliation(s)
- Robert Vassar
- Department of Cell and Molecular Biology, Feinberg University School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peer-Hendrik Kuhn
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
- Adolf-Butenandt Institute, Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Matthew E. Kennedy
- Neurosciences, Merck Research Labs, Boston, Massachusetts, USA
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
- Graduate programs of the Zurich Center for Integrative Human Physiology and Zurich Neuroscience Center, University of Zurich, Zurich, Switzerland
| | - Philip C. Wong
- Departments of Pathology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stefan F. Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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31
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Namba T, Kibe Y, Funahashi Y, Nakamuta S, Takano T, Ueno T, Shimada A, Kozawa S, Okamoto M, Shimoda Y, Oda K, Wada Y, Masuda T, Sakakibara A, Igarashi M, Miyata T, Faivre-Sarrailh C, Takeuchi K, Kaibuchi K. Pioneering axons regulate neuronal polarization in the developing cerebral cortex. Neuron 2014; 81:814-29. [PMID: 24559674 DOI: 10.1016/j.neuron.2013.12.015] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2013] [Indexed: 01/06/2023]
Abstract
The polarization of neurons, which mainly includes the differentiation of axons and dendrites, is regulated by cell-autonomous and non-cell-autonomous factors. In the developing central nervous system, neuronal development occurs in a heterogeneous environment that also comprises extracellular matrices, radial glial cells, and neurons. Although many cell-autonomous factors that affect neuronal polarization have been identified, the microenvironmental cues involved in neuronal polarization remain largely unknown. Here, we show that neuronal polarization occurs in a microenvironment in the lower intermediate zone, where the cell adhesion molecule transient axonal glycoprotein-1 (TAG-1) is expressed in cortical efferent axons. The immature neurites of multipolar cells closely contact TAG-1-positive axons and generate axons. Inhibition of TAG-1-mediated cell-to-cell interaction or its downstream kinase Lyn impairs neuronal polarization. These results show that the TAG-1-mediated cell-to-cell interaction between the unpolarized multipolar cells and the pioneering axons regulates the polarization of multipolar cells partly through Lyn kinase and Rac1.
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Affiliation(s)
- Takashi Namba
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Yuji Kibe
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Yasuhiro Funahashi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Shinichi Nakamuta
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Tetsuya Takano
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Takuji Ueno
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Akiko Shimada
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Sachi Kozawa
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Mayumi Okamoto
- Department of Anatomy and Cell Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Yasushi Shimoda
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata 940-2188, Japan
| | - Kanako Oda
- Experimental Animal Resource, Brain Research Institute, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahi-machi, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Yoshino Wada
- Division of Molecular and Cellular Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahi-machi, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Tomoyuki Masuda
- Department of Neurobiology, University of Tsukuba School of Medicine, Ibaraki 305-8577, Japan
| | - Akira Sakakibara
- Department of Anatomy and Cell Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Michihiro Igarashi
- Division of Molecular and Cellular Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahi-machi, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Takaki Miyata
- Department of Anatomy and Cell Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
| | - Catherine Faivre-Sarrailh
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, UMR 7286 CNRS, Marseille, France
| | - Kosei Takeuchi
- Division of Molecular and Cellular Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahi-machi, Chuo-ku, Niigata, Niigata 951-8510, Japan; Department of Biology, School of Medicine, Aichi Medical University, Yazako, Nagakute, Aichi 480-1195, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya 466-8550, Japan.
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Gautam V, D'Avanzo C, Hebisch M, Kovacs DM, Kim DY. BACE1 activity regulates cell surface contactin-2 levels. Mol Neurodegener 2014; 9:4. [PMID: 24405708 PMCID: PMC3899608 DOI: 10.1186/1750-1326-9-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 12/04/2013] [Indexed: 01/06/2023] Open
Abstract
Background Although BACE1 is a major therapeutic target for Alzheimer’s disease (AD), potential side effects of BACE1 inhibition are not well characterized. BACE1 cleaves over 60 putative substrates, however the majority of these cleavages have not been characterized. Here we investigated BACE1-mediated cleavage of human contactin-2, a GPI-anchored cell adhesion molecule. Results Our initial protein sequence analysis showed that contactin-2 harbors a strong putative BACE1 cleavage site close to its GPI membrane linker domain. When we overexpressed BACE1 in CHO cells stably transfected with human contactin-2, we found increased release of soluble contactin-2 in the conditioned media. Conversely, pharmacological inhibition of BACE1 in CHO cells expressing human contactin-2 and mouse primary neurons decreased soluble contactin-2 secretion. The BACE1 cleavage site mutation 1008MM/AA dramatically impaired soluble contactin-2 release. We then asked whether contactin-2 release induced by BACE1 expression would concomitantly decrease cell surface levels of contactin-2. Using immunofluorescence and surface-biotinylation assays, we showed that BACE1 activity tightly regulates contactin-2 surface levels in CHO cells as well as in mouse primary neurons. Finally, contactin-2 levels were decreased in Alzheimer’s disease brain samples correlating inversely with elevated BACE1 levels in the same samples. Conclusion Our results clearly demonstrate that mouse and human contactin-2 are physiological substrates for BACE1. BACE1-mediated contactin-2 cleavage tightly regulates the surface expression of contactin-2 in neuronal cells. Given the role of contactin-2 in cell adhesion, neurite outgrowth and axon guidance, our data suggest that BACE1 may play an important role in these physiological processes by regulating contactin-2 surface levels.
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Affiliation(s)
| | | | | | - Dora M Kovacs
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
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Faivre-Sarrailh C, Devaux JJ. Neuro-glial interactions at the nodes of Ranvier: implication in health and diseases. Front Cell Neurosci 2013; 7:196. [PMID: 24194699 PMCID: PMC3810605 DOI: 10.3389/fncel.2013.00196] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/08/2013] [Indexed: 01/06/2023] Open
Abstract
Specific cell adhesion molecules (CAMs) are dedicated to the formation of axo-glial contacts at the nodes of Ranvier of myelinated axons. They play a central role in the organization and maintenance of the axonal domains: the node, paranode, and juxtaparanode. In particular, CAMs are essential for the accumulation of voltage-gated sodium channels at the nodal gap that ensures the rapid and saltatory propagation of the action potentials (APs). The mechanisms regulating node formation are distinct in the central and peripheral nervous systems, and recent studies have highlighted the relative contribution of paranodal junctions and nodal extracellular matrix. In addition, CAMs at the juxtaparanodal domains mediate the clustering of voltage-gated potassium channels which regulate the axonal excitability. In several human pathologies, the axo-glial contacts are altered leading to disruption of the nodes of Ranvier or mis-localization of the ion channels along the axons. Node alterations and the failure of APs to propagate correctly from nodes to nodes along the axons both contribute to the disabilities in demyelinating diseases. This article reviews the mechanisms regulating the association of the axo-glial complexes and the role of CAMs in inherited and acquired neurological diseases.
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Ha S, Stottmann RW, Furley AJ, Beier DR. A forward genetic screen in mice identifies mutants with abnormal cortical patterning. ACTA ACUST UNITED AC 2013; 25:167-79. [PMID: 23968836 DOI: 10.1093/cercor/bht209] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Formation of a 6-layered cortical plate and axon tract patterning are key features of cerebral cortex development. Abnormalities of these processes may be the underlying cause for a range of functional disabilities seen in human neurodevelopmental disorders. To identify mouse mutants with defects in cortical lamination or corticofugal axon guidance, N-ethyl-N-nitrosourea (ENU) mutagenesis was performed using mice expressing LacZ reporter genes in layers II/III and V of the cortex (Rgs4-lacZ) or in corticofugal axons (TAG1-tau-lacZ). Four lines with abnormal cortical lamination have been identified. One of these was a splice site mutation in reelin (Reln) that results in a premature stop codon and the truncation of the C-terminal region (CTR) domain of reelin. Interestingly, this novel allele of Reln did not display cerebellar malformation or ataxia, and this is the first report of a Reln mutant without a cerebellar defect. Four lines with abnormal cortical axon development were also identified, one of which was found by whole-genome resequencing to carry a mutation in Lrp2. These findings demonstrated that the application of ENU mutagenesis to mice carrying transgenic reporters marking cortical anatomy is a sensitive and specific method to identify mutations that disrupt patterning of the developing brain.
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Affiliation(s)
- Seungshin Ha
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Rolf W Stottmann
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Divisions of Human Genetics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA and
| | - Andrew J Furley
- Department of Biomedical Science, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David R Beier
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA
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Zoupi L, Markoullis K, Kleopa KA, Karagogeos D. Alterations of juxtaparanodal domains in two rodent models of CNS demyelination. Glia 2013; 61:1236-49. [DOI: 10.1002/glia.22511] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/20/2013] [Indexed: 01/15/2023]
Affiliation(s)
| | - Kyriaki Markoullis
- Neuroscience Laboratory and Neurology Clinics; The Cyprus Institute of Neurology and Genetics (CING); P.O. Box 23462, 1683 Nicosia; Cyprus
| | - Kleopas A. Kleopa
- Neuroscience Laboratory and Neurology Clinics; The Cyprus Institute of Neurology and Genetics (CING); P.O. Box 23462, 1683 Nicosia; Cyprus
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Stogmann E, Reinthaler E, ElTawil S, El Etribi MA, Hemeda M, El Nahhas N, Gaber AM, Fouad A, Edris S, Benet-Pages A, Eck SH, Pataraia E, Mei D, Brice A, Lesage S, Guerrini R, Zimprich F, Strom TM, Zimprich A. Autosomal recessive cortical myoclonic tremor and epilepsy: association with a mutation in the potassium channel associated gene CNTN2. Brain 2013; 136:1155-60. [DOI: 10.1093/brain/awt068] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Ntzouni MP, Skouroliakou A, Kostomitsopoulos N, Margaritis LH. Transient and cumulative memory impairments induced by GSM 1.8 GHz cell phone signal in a mouse model. Electromagn Biol Med 2013; 32:95-120. [PMID: 23320614 DOI: 10.3109/15368378.2012.709207] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study was designed to investigate the transient and cumulative impairments in spatial and non-spatial memory of C57Bl/6J mice exposed to GSM 1.8 GHz signal for 90 min daily by a typical cellular (mobile) phone at a specific absorption rate value of 0.11 W/kg. Free-moving male mice 2 months old were irradiated in two experimental protocols, lasting for 66 and for 148 days respectively. Each protocol used three groups of animals (n = 8 each for exposed, sham exposed and controls) in combination with two behavioural paradigms, the object recognition task and the object location task sequentially applied at different time points. One-way analysis of variance revealed statistically significant impairments of both types of memory gradually accumulating, with more pronounced effects on the spatial memory. The impairments persisted even 2 weeks after interruption of the 8 weeks daily exposure, whereas the memory of mice as detected by both tasks showed a full recovery approximately 1 month later. Intermittent every other day exposure for 1 month had no effect on both types of memory. The data suggest that visual information processing mechanisms in hippocampus, perirhinal and entorhinal cortex are gradually malfunctioning upon long-term daily exposure, a phenotype that persists for at least 2 weeks after interruption of radiation, returning to normal memory performance levels 4 weeks later. It is postulated that cellular repair mechanisms are operating to eliminate the memory affecting molecules. The overall contribution of several possible mechanisms to the observed cumulative and transient impairments in spatial and non-spatial memory is discussed.
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Affiliation(s)
- Maria P Ntzouni
- Department of Cell Biology and Biophysics, Faculty of Biology, Athens University, Panepistimiopolis, Athens, Greece
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38
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Bormuth I, Yan K, Yonemasu T, Gummert M, Zhang M, Wichert S, Grishina O, Pieper A, Zhang W, Goebbels S, Tarabykin V, Nave KA, Schwab MH. Neuronal basic helix-loop-helix proteins Neurod2/6 regulate cortical commissure formation before midline interactions. J Neurosci 2013; 33:641-51. [PMID: 23303943 PMCID: PMC6704922 DOI: 10.1523/jneurosci.0899-12.2013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 10/29/2012] [Accepted: 11/05/2012] [Indexed: 12/31/2022] Open
Abstract
Establishment of long-range fiber tracts by neocortical projection neurons is fundamental for higher brain functions. The molecular control of axon tract formation, however, is still poorly understood. Here, we have identified basic helix-loop-helix (bHLH) transcription factors Neurod2 and Neurod6 as key regulators of fasciculation and targeted axogenesis in the mouse neocortex. In Neurod2/6 double-mutant mice, callosal axons lack expression of the cell adhesion molecule Contactin2, defasciculate in the subventricular zone, and fail to grow toward the midline without forming Probst bundles. Instead, mutant axons overexpress Robo1 and follow random trajectories into the ipsilateral cortex. In contrast to long-range axogenesis, generation and maintenance of pyramidal neurons and initial axon outgrowth are grossly normal, suggesting that these processes are under distinct transcriptional control. Our findings define a new stage in corpus callosum development and demonstrate that neocortical projection neurons require transcriptional specification by neuronal bHLH proteins to execute an intrinsic program of remote connectivity.
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Affiliation(s)
- Ingo Bormuth
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
- Charité–Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, NeuroCure Cluster of Excellence, D-10115 Berlin, Germany, and
| | - Kuo Yan
- Charité–Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, NeuroCure Cluster of Excellence, D-10115 Berlin, Germany, and
| | - Tomoko Yonemasu
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
| | - Maike Gummert
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
| | - Mingyue Zhang
- University of Münster, Department of Psychiatry, Laboratory of Molecular Psychiatry, D-48149 Münster, Germany
| | - Sven Wichert
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
| | - Olga Grishina
- Charité–Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, NeuroCure Cluster of Excellence, D-10115 Berlin, Germany, and
| | - Alexander Pieper
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
| | - Weiqi Zhang
- University of Münster, Department of Psychiatry, Laboratory of Molecular Psychiatry, D-48149 Münster, Germany
| | - Sandra Goebbels
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
| | - Victor Tarabykin
- Charité–Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, NeuroCure Cluster of Excellence, D-10115 Berlin, Germany, and
| | - Klaus-Armin Nave
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
| | - Markus H. Schwab
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, D-37075 Göttingen, Germany
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Azizi G, Mirshafiey A. The potential role of proinflammatory and antiinflammatory cytokines in Alzheimer disease pathogenesis. Immunopharmacol Immunotoxicol 2012; 34:881-95. [DOI: 10.3109/08923973.2012.705292] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Huang CY, Chu D, Hwang WC, Tsaur ML. Coexpression of high-voltage-activated ion channels Kv3.4 and Cav1.2 in pioneer axons during pathfinding in the developing rat forebrain. J Comp Neurol 2012; 520:3650-72. [DOI: 10.1002/cne.23119] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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41
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Cameron DA, Middleton FA, Chenn A, Olson EC. Hierarchical clustering of gene expression patterns in the Eomes + lineage of excitatory neurons during early neocortical development. BMC Neurosci 2012; 13:90. [PMID: 22852769 PMCID: PMC3583225 DOI: 10.1186/1471-2202-13-90] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 07/11/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cortical neurons display dynamic patterns of gene expression during the coincident processes of differentiation and migration through the developing cerebrum. To identify genes selectively expressed by the Eomes + (Tbr2) lineage of excitatory cortical neurons, GFP-expressing cells from Tg(Eomes::eGFP) Gsat embryos were isolated to > 99% purity and profiled. RESULTS We report the identification, validation and spatial grouping of genes selectively expressed within the Eomes + cortical excitatory neuron lineage during early cortical development. In these neurons 475 genes were expressed ≥ 3-fold, and 534 genes ≤ 3-fold, compared to the reference population of neuronal precursors. Of the up-regulated genes, 328 were represented at the Genepaint in situ hybridization database and 317 (97%) were validated as having spatial expression patterns consistent with the lineage of differentiating excitatory neurons. A novel approach for quantifying in situ hybridization patterns (QISP) across the cerebral wall was developed that allowed the hierarchical clustering of genes into putative co-regulated groups. Forty four candidate genes were identified that show spatial expression with Intermediate Precursor Cells, 49 candidate genes show spatial expression with Multipolar Neurons, while the remaining 224 genes achieved peak expression in the developing cortical plate. CONCLUSIONS This analysis of differentiating excitatory neurons revealed the expression patterns of 37 transcription factors, many chemotropic signaling molecules (including the Semaphorin, Netrin and Slit signaling pathways), and unexpected evidence for non-canonical neurotransmitter signaling and changes in mechanisms of glucose metabolism. Over half of the 317 identified genes are associated with neuronal disease making these findings a valuable resource for studies of neurological development and disease.
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Affiliation(s)
- David A Cameron
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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42
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Buchner DA, Geisinger JM, Glazebrook PA, Morgan MG, Spiezio SH, Kaiyala KJ, Schwartz MW, Sakurai T, Furley AJ, Kunze DL, Croniger CM, Nadeau JH. The juxtaparanodal proteins CNTNAP2 and TAG1 regulate diet-induced obesity. Mamm Genome 2012; 23:431-42. [PMID: 22752552 DOI: 10.1007/s00335-012-9400-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 05/21/2012] [Indexed: 11/26/2022]
Abstract
Despite considerable effort, the identification of genes that regulate complex multigenic traits such as obesity has proven difficult with conventional methodologies. The use of a chromosome substitution strain-based mapping strategy based on deep congenic analysis overcame many of the difficulties associated with gene discovery and led to the finding that the juxtaparanodal proteins CNTNAP2 and TAG1 regulate diet-induced obesity. The effects of a mild Cntnap2 mutation on body weight were highly dependent on genetic background, as both obesity-promoting and obesity-resistant effects of Cntnap2 were observed on different genetic backgrounds. The more severe effect of complete TAG1 deficiency, by decreasing food intake, completely prevented the weight gain normally associated with high-fat-diet feeding. Together, these studies implicate two novel proteins in the regulation of diet-induced obesity. Moreover, as juxtaparanodal proteins have previously been implicated in various neurological disorders, our results suggest a potential genetic and molecular link between obesity and diseases such as autism and epilepsy.
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Affiliation(s)
- David A Buchner
- Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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Becker EBE, Zuliani L, Pettingill R, Lang B, Waters P, Dulneva A, Sobott F, Wardle M, Graus F, Bataller L, Robertson NP, Vincent A. Contactin-associated protein-2 antibodies in non-paraneoplastic cerebellar ataxia. J Neurol Neurosurg Psychiatry 2012; 83:437-40. [PMID: 22338029 PMCID: PMC3297806 DOI: 10.1136/jnnp-2011-301506] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Relatively few studies have searched for potentially pathogenic antibodies in non-paraneoplastic patients with cerebellar ataxia. METHODS AND RESULTS We first screened sera from 52 idiopathic ataxia patients for binding of serum IgG antibodies to cerebellar neurons. One strong-binding serum was selected for immunoprecipitation and mass spectrometry, which resulted in the identification of contactin-associated protein 2 (CASPR2) as a major antigen. CASPR2 antibodies were then found by a cell-based assay in 9/88 (10%) ataxia patients, compared to 3/144 (2%) multiple sclerosis or dementia controls (p=0.011). CASPR2 is strongly expressed in the cerebellum, only partly in association with voltage-gated potassium channels. CONCLUSIONS Prospective studies are now needed to see whether identification of CASPR2 antibodies has relevance for the diagnosis and treatment of idiopathic cerebellar ataxia.
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Affiliation(s)
- Esther B E Becker
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford University, Oxford, UK
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Boronat A, Sepúlveda M, Llufriu S, Sabater L, Blanco Y, Gabilondo I, Solà N, Villoslada P, Dalmau J, Graus F, Saiz A. Analysis of antibodies to surface epitopes of contactin-2 in multiple sclerosis. J Neuroimmunol 2012; 244:103-6. [PMID: 22245283 DOI: 10.1016/j.jneuroim.2011.12.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 11/16/2011] [Accepted: 12/16/2011] [Indexed: 01/17/2023]
Abstract
Contactin-2 was recently identified as an autoantigen targeted by T-cells and autoantibodies in multiple sclerosis (MS). Here we analyzed the frequency of antibodies to contactin-2 (contactin-2-ab) by a cell-based assay in the serum from 105 MS patients and at least 5 years of follow-up (19 clinically isolated syndromes, 51 relapsing-remitting, 20 secondary-progressive, and 15 primary-progressive). Contactin-2-ab were detected in 4 (7.8%) relapsing-remitting patients. Clinical and magnetic resonance imaging characteristics were not significantly different from the rest of relapsing-remitting patients. In conclusion, contactin-2-ab are identified in a minority of MS patients but their presence is not associated with a particular clinical-radiological profile.
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Affiliation(s)
- Anna Boronat
- Center for Neuroimmunology, Service of Neurology, Hospital Clinic and Institut d' Investigació Biomèdica August Pi i Sunyer, Universitat de Barcelona, Barcelona, Spain
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Duflocq A, Chareyre F, Giovannini M, Couraud F, Davenne M. Characterization of the axon initial segment (AIS) of motor neurons and identification of a para-AIS and a juxtapara-AIS, organized by protein 4.1B. BMC Biol 2011; 9:66. [PMID: 21958379 PMCID: PMC3198992 DOI: 10.1186/1741-7007-9-66] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 09/29/2011] [Indexed: 11/26/2022] Open
Abstract
Background The axon initial segment (AIS) plays a crucial role: it is the site where neurons initiate their electrical outputs. Its composition in terms of voltage-gated sodium (Nav) and voltage-gated potassium (Kv) channels, as well as its length and localization determine the neuron's spiking properties. Some neurons are able to modulate their AIS length or distance from the soma in order to adapt their excitability properties to their activity level. It is therefore crucial to characterize all these parameters and determine where the myelin sheath begins in order to assess a neuron's excitability properties and ability to display such plasticity mechanisms. If the myelin sheath starts immediately after the AIS, another question then arises as to how would the axon be organized at its first myelin attachment site; since AISs are different from nodes of Ranvier, would this particular axonal region resemble a hemi-node of Ranvier? Results We have characterized the AIS of mouse somatic motor neurons. In addition to constant determinants of excitability properties, we found heterogeneities, in terms of AIS localization and Nav composition. We also identified in all α motor neurons a hemi-node-type organization, with a contactin-associated protein (Caspr)+ paranode-type, as well as a Caspr2+ and Kv1+ juxtaparanode-type compartment, referred to as a para-AIS and a juxtapara (JXP)-AIS, adjacent to the AIS, where the myelin sheath begins. We found that Kv1 channels appear in the AIS, para-AIS and JXP-AIS concomitantly with myelination and are progressively excluded from the para-AIS. Their expression in the AIS and JXP-AIS is independent from transient axonal glycoprotein-1 (TAG-1)/Caspr2, in contrast to juxtaparanodes, and independent from PSD-93. Data from mice lacking the cytoskeletal linker protein 4.1B show that this protein is necessary to form the Caspr+ para-AIS barrier, ensuring the compartmentalization of Kv1 channels and the segregation of the AIS, para-AIS and JXP-AIS. Conclusions α Motor neurons have heterogeneous AISs, which underlie different spiking properties. However, they all have a para-AIS and a JXP-AIS contiguous to their AIS, where the myelin sheath begins, which might limit some AIS plasticity. Protein 4.1B plays a key role in ensuring the proper molecular compartmentalization of this hemi-node-type region.
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Zoupi L, Savvaki M, Karagogeos D. Axons and myelinating glia: An intimate contact. IUBMB Life 2011; 63:730-5. [PMID: 21793162 DOI: 10.1002/iub.513] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 04/18/2011] [Indexed: 01/06/2023]
Abstract
The coordination of the vertebrate nervous system requires high velocity signal transmission between different brain areas. High speed nerve conduction is achieved in the myelinated fibers of both the central and the peripheral nervous system where the myelin sheath acts as an insulator of the axon. The interactions between the glial cell and the adjacent axon, namely axo-glial interactions, segregate the fiber in distinct molecular and functional domains that ensure the rapid propagation of action potentials. These domains are the node of Ranvier, the paranode, the juxtaparanode and the internode and are characterized by multiprotein complexes between voltage-gated ion channels, cell adhesion molecules, members of the Neurexin family and cytoskeletal proteins. In the present review, we outline recent evidence on the key players of axo-glial interactions, depicting their importance in myelinated fiber physiology and disease.
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Affiliation(s)
- Lida Zoupi
- Department of Basic Science, Faculty of Medicine, University of Crete, Institute of Molecular Biology & Biotechnology-FoRTH, Heraklion, Greece
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47
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Short-term memory in mice is affected by mobile phone radiation. PATHOPHYSIOLOGY 2011; 18:193-9. [DOI: 10.1016/j.pathophys.2010.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 10/28/2010] [Accepted: 11/01/2010] [Indexed: 11/21/2022] Open
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48
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Gu C, Gu Y. Clustering and activity tuning of Kv1 channels in myelinated hippocampal axons. J Biol Chem 2011; 286:25835-47. [PMID: 21602278 DOI: 10.1074/jbc.m111.219113] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Precise localization of axonal ion channels is crucial for proper electrical and chemical functions of axons. In myelinated axons, Kv1 (Shaker) voltage-gated potassium (Kv) channels are clustered in the juxtaparanodal regions flanking the node of Ranvier. The clustering can be disrupted by deletion of various proteins in mice, including contactin-associated protein-like 2 (Caspr2) and transient axonal glycoprotein-1 (TAG-1), a glycosylphosphatidylinositol-anchored cell adhesion molecule. However, the mechanism and function of Kv1 juxtaparanodal clustering remain unclear. Here, using a new myelin coculture of hippocampal neurons and oligodendrocytes, we report that tyrosine phosphorylation plays a critical role in TAG-1-mediated clustering of axonal Kv1.2 channels. In the coculture, myelin specifically ensheathed axons but not dendrites of hippocampal neurons and clustered endogenous axonal Kv1.2 into internodes. The trans-homophilic interaction of TAG-1 was sufficient to position Kv1.2 clusters on axonal membranes in a neuron/HEK293 coculture. Mutating a tyrosine residue (Tyr⁴⁵⁸) in the Kv1.2 C terminus or blocking tyrosine phosphorylation disrupted myelin- and TAG-1-mediated clustering of axonal Kv1.2. Furthermore, Kv1.2 voltage dependence and activation threshold were reduced by TAG-1 coexpression. This effect was eliminated by the Tyr⁴⁵⁸ mutation or by cholesterol depletion. Taken together, our studies suggest that myelin regulates both trafficking and activity of Kv1 channels along hippocampal axons through TAG-1.
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Affiliation(s)
- Chen Gu
- Department of Neuroscience and Center for Molecular Neurobiology, Ohio State University, Columbus, Ohio 43210, USA.
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Cottrell CE, Bir N, Varga E, Alvarez CE, Bouyain S, Zernzach R, Thrush DL, Evans J, Trimarchi M, Butter EM, Cunningham D, Gastier-Foster JM, McBride KL, Herman GE. Contactin 4 as an autism susceptibility locus. Autism Res 2011; 4:189-99. [PMID: 21308999 DOI: 10.1002/aur.184] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 12/15/2010] [Indexed: 01/05/2023]
Abstract
Structural and sequence variation have been described in several members of the contactin (CNTN) and contactin-associated protein (CNTNAP) gene families in association with neurodevelopmental disorders, including autism. Using array comparative genome hybridization (CGH), we identified a maternally inherited ∼535 kb deletion at 3p26.3 encompassing the 5' end of the contactin 4 gene (CNTN4) in a patient with autism. Based on this finding and previous reports implicating genomic rearrangements of CNTN4 in autism spectrum disorders (ASDs) and 3p- microdeletion syndrome, we undertook sequencing of the coding regions of the gene in a local ASD cohort in comparison with a set of controls. Unique missense variants were identified in 4 of 75 unrelated individuals with ASD, as well as in 1 of 107 controls. All of the amino acid substitutions were nonsynonomous, occurred at evolutionarily conserved positions, and were, thus, felt likely to be deleterious. However, these data did not reach statistical significance, nor did the variants segregate with disease within all of the ASD families. Finally, there was no detectable difference in binding of two of the variants to the interacting protein PTPRG in vitro. Thus, additional larger studies will be necessary to determine whether CNTN4 functions as an autism susceptibility locus in combination with other genetic and/or environmental factors.
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Affiliation(s)
- Catherine E Cottrell
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA
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The expression of TAG-1 in glial cells is sufficient for the formation of the juxtaparanodal complex and the phenotypic rescue of tag-1 homozygous mutants in the CNS. J Neurosci 2010; 30:13943-54. [PMID: 20962216 DOI: 10.1523/jneurosci.2574-10.2010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Myelinated fibers are organized into specialized domains that ensure the rapid propagation of action potentials and are characterized by protein complexes underlying axoglial interactions. TAG-1 (Transient Axonal Glycoprotein-1), a cell adhesion molecule of the Ig superfamily, is expressed by neurons as well as by myelinating glia. It is essential for the molecular organization of myelinated fibers as it maintains the integrity of the juxtaparanodal region through its interactions with Caspr2 and the voltage-gated potassium channels (VGKCs) on the axolemma. Since TAG-1 is the only known component of the juxtaparanodal complex expressed by the glial cell, it is important to clarify its role in the molecular organization of juxtaparanodes. For this purpose, we generated transgenic mice that exclusively express TAG-1 in oligodendrocytes and lack endogenous gene expression (Tag-1(-/-);plp(Tg(rTag-1))). Phenotypic analysis clearly demonstrates that glial TAG-1 is sufficient for the proper organization and maintenance of the juxtaparanodal domain in the CNS. Biochemical analysis shows that glial TAG-1 physically interacts with Caspr2 and VGKCs. Ultrastructural and behavioral analysis of Tag-1(-/-);plp(Tg(rTag-1)) mice shows that the expression of glial TAG-1 is sufficient to restore the axonal and myelin deficits as well as the behavioral defects observed in Tag-1(-/-) animals. Together, these data highlight the pivotal role of myelinating glia on axonal domain differentiation and organization.
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