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Mishra S, Rai A, Srivastava P, Phadke SR. A mild phenotype of LGI4-Related arthrogryposis multiplex congenita with intrafamilial variability. Eur J Med Genet 2020; 63:103756. [DOI: 10.1016/j.ejmg.2019.103756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/10/2019] [Accepted: 09/08/2019] [Indexed: 01/22/2023]
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Loss-of-Function Mutations in LGI4, a Secreted Ligand Involved in Schwann Cell Myelination, Are Responsible for Arthrogryposis Multiplex Congenita. Am J Hum Genet 2017; 100:659-665. [PMID: 28318499 DOI: 10.1016/j.ajhg.2017.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/16/2017] [Indexed: 01/26/2023] Open
Abstract
Arthrogryposis multiplex congenita (AMC) is a developmental condition characterized by multiple joint contractures resulting from reduced or absent fetal movements. Through genetic mapping of disease loci and whole-exome sequencing in four unrelated multiplex families presenting with severe AMC, we identified biallelic loss-of-function mutations in LGI4 (leucine-rich glioma-inactivated 4). LGI4 is a ligand secreted by Schwann cells that regulates peripheral nerve myelination via its cognate receptor ADAM22 expressed by neurons. Immunolabeling experiments and transmission electron microscopy of the sciatic nerve from one of the affected individuals revealed a lack of myelin. Functional tests using affected individual-derived iPSCs showed that these germline mutations caused aberrant splicing of the endogenous LGI4 transcript and in a cell-based assay impaired the secretion of truncated LGI4 protein. This is consistent with previous studies reporting arthrogryposis in Lgi4-deficient mice due to peripheral hypomyelination. This study adds to the recent reports implicating defective axoglial function as a key cause of AMC.
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Helmbrecht MS, Soellner H, Truckenbrodt AML, Sundermeier J, Cohrs C, Hans W, de Angelis MH, Feuchtinger A, Aichler M, Fouad K, Huber AB. Loss of Npn1 from motor neurons causes postnatal deficits independent from Sema3A signaling. Dev Biol 2014; 399:2-14. [PMID: 25512301 DOI: 10.1016/j.ydbio.2014.11.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 12/20/2022]
Abstract
The correct wiring of neuronal circuits is of crucial importance for the function of the vertebrate nervous system. Guidance cues like the neuropilin receptors (Npn) and their ligands, the semaphorins (Sema) provide a tight spatiotemporal control of sensory and motor axon growth and guidance. Among this family of guidance partners the Sema3A-Npn1 interaction has been shown to be of great importance, since defective signaling leads to wiring deficits and defasciculation. For the embryonic stage these defects have been well described, however, also after birth the organism can adapt to new challenges by compensational mechanisms. Therefore, we used the mouse lines Olig2-Cre;Npn1(cond) and Npn1(Sema-) to investigate how postnatal organisms cope with the loss of Npn1 selectively from motor neurons or a systemic dysfunctional Sema3A-Npn1 signaling in the entire organism, respectively. While in Olig2-Cre(+);Npn1(cond-/-) mice clear anatomical deficits in paw posturing, bone structure, as well as muscle and nerve composition became evident, Npn1(Sema-) mutants appeared anatomically normal. Furthermore, Olig2-Cre(+);Npn1(cond) mutants revealed a dysfunctional extensor muscle innervation after single-train stimulation of the N.radial. Interestingly, these mice did not show obvious deficits in voluntary locomotion, however, skilled motor function was affected. In contrast, Npn1(Sema-) mutants were less affected in all behavioral tests and able to improve their performance over time. Our data suggest that loss of Sema3A-Npn1 signaling is not the only cause for the observed deficits in Olig2-Cre(+);Npn1(cond-/-) mice and that additional, yet unknown binding partners for Npn1 may be involved that allow Npn1(Sema-) mutants to compensate for their developmental deficits.
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Affiliation(s)
- Michaela S Helmbrecht
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany.
| | - Heidi Soellner
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Anna M L Truckenbrodt
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Julia Sundermeier
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Christian Cohrs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany; DFG-Research Center for Regenerative Therapies Dresden, Technische Universität and Paul Langerhans Institute Dresden, German Center for Diabetes Research (DZD), Germany
| | - Wolfgang Hans
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Martin Hrabě de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany; Chair of Experimental Genetics, Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85354 Freising-Weihenstephan, Germany; German Center for Diabetes Research (DZD), Ingostädter Landstr. 1, 85764 Neuherberg, Germany
| | - Annette Feuchtinger
- Research Unit Analytical Pathology, Insititute of Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Michaela Aichler
- Research Unit Analytical Pathology, Insititute of Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - Karim Fouad
- Faculty of Rehabilitation Medicine and Centre for Neuroscience, University of Alberta, Canada
| | - Andrea B Huber
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany.
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Luo S, Jaegle M, Li R, Ehring GR, Meijer D, Levinson SR. The sodium channel isoform transition at developing nodes of ranvier in the peripheral nervous system: Dependence on a Genetic program and myelination-induced cluster formation. J Comp Neurol 2014; 522:4057-73. [DOI: 10.1002/cne.23656] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Songjiang Luo
- Department of Comprehensive Dentistry; University of Texas Health Science Center; San Antonio Texas 78229
| | - Martine Jaegle
- Department of Cell Biology and Genetics; Erasmus University Rotterdam; 3000DR Rotterdam The Netherlands
| | - Roy Li
- Allergan; Irvine California 92612
| | | | - Dies Meijer
- Department of Cell Biology and Genetics; Erasmus University Rotterdam; 3000DR Rotterdam The Netherlands
- Centre for Neuroregeneration; University of Edinburgh; Edinburgh EH16 4SB United Kingdom
| | - Simon R. Levinson
- Department of Physiology and Biophysics; School of Medicine, University of Colorado Anschutz Medical Campus; Aurora Colorado 80045
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Abstract
Here we review recent research into the mechanisms of chronic pain that has focused on neuronal sodium channels, a target of classic analgesic agents. We first discuss evidence that specific sodium channel isoforms are essential for the detection and conduction of normal acutely painful stimuli from nociceptors. We then review findings that show changes in sodium channel expression and localization in chronic inflammation and nerve injury in animal and human tissues. We conclude by discussing the role that myelination plays in organizing and maintaining sodium channel clusters at nodes of Ranvier in normal development and how inflammatory processes or nerve injury alter the characteristics of such clusters. Based on these findings, we suggest that chronic pain may in part result from partial demyelination of axons during chronic injury, which creates aberrant sodium channel clusters that serve as sites of ectopic sensitivity or spontaneous activity.
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Affiliation(s)
- Simon R Levinson
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
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Unmyelinated nerve fibers in the human dental pulp express markers for myelinated fibers and show sodium channel accumulations. BMC Neurosci 2012; 13:29. [PMID: 22429267 PMCID: PMC3323891 DOI: 10.1186/1471-2202-13-29] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 03/19/2012] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The dental pulp is a common source of pain and is used to study peripheral inflammatory pain mechanisms. Results show most fibers are unmyelinated, yet recent findings in experimental animals suggest many pulpal afferents originate from fibers that are myelinated at more proximal locations. Here we use the human dental pulp and confocal microscopy to examine the staining relationships of neurofilament heavy (NFH), a protein commonly expressed in myelinated afferents, with other markers to test the possibility that unmyelinated pulpal afferents originate from myelinated axons. Other staining relationships studied included myelin basic protein (MBP), protein gene product (PGP) 9.5 to identify all nerve fibers, tyrosine hydroxylase (TH) to identify sympathetic fibers, contactin-associated protein (caspr) to identify nodal sites, S-100 to identify Schwann cells and sodium channels (NaChs). RESULTS Results show NFH expression in most PGP9.5 fibers except those with TH and include the broad expression of NFH in axons lacking MBP. Fibers with NFH and MBP show NaCh clusters at nodal sites as expected, but surprisingly, NaCh accumulations are also seen in unmyelinated fibers with NFH, and in fibers with NFH that lack Schwann cell associations. CONCLUSIONS The expression of NFH in most axons suggests a myelinated origin for many pulpal afferents, while the presence of NaCh clusters in unmyelinated fibers suggests an inherent capacity for the unmyelinated segments of myelinated fibers to form NaCh accumulations. These findings have broad implications on the use of dental pulp to study pain mechanisms and suggest possible novel mechanisms responsible for NaCh cluster formation and neuronal excitability.
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Novak N, Bar V, Sabanay H, Frechter S, Jaegle M, Snapper SB, Meijer D, Peles E. N-WASP is required for membrane wrapping and myelination by Schwann cells. ACTA ACUST UNITED AC 2011; 192:243-50. [PMID: 21263026 PMCID: PMC3172181 DOI: 10.1083/jcb.201010013] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
N-WASP–deficient Schwann cells sort and ensheath axons but arrest at the promyelinating stage. During peripheral nerve myelination, Schwann cells sort larger axons, ensheath them, and eventually wrap their membrane to form the myelin sheath. These processes involve extensive changes in cell shape, but the exact mechanisms involved are still unknown. Neural Wiskott–Aldrich syndrome protein (N-WASP) integrates various extracellular signals to control actin dynamics and cytoskeletal reorganization through activation of the Arp2/3 complex. By generating mice lacking N-WASP in myelinating Schwann cells, we show that N-WASP is crucial for myelination. In N-WASP–deficient nerves, Schwann cells sort and ensheath axons, but most of them fail to myelinate and arrest at the promyelinating stage. Yet, a limited number of Schwann cells form unusually short internodes, containing thin myelin sheaths, with the occasional appearance of myelin misfoldings. These data suggest that regulation of actin filament nucleation in Schwann cells by N-WASP is crucial for membrane wrapping, longitudinal extension, and myelination.
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Affiliation(s)
- Nurit Novak
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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Bermingham JR, Shearin H, Pennington J, O'Moore J, Jaegle M, Driegen S, van Zon A, Darbas A, Ozkaynak E, Ryu EJ, Milbrandt J, Meijer D. The claw paw mutation reveals a role for Lgi4 in peripheral nerve development. Nat Neurosci 2005; 9:76-84. [PMID: 16341215 DOI: 10.1038/nn1598] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 10/18/2005] [Indexed: 12/24/2022]
Abstract
Peripheral nerve development results from multiple cellular interactions between axons, Schwann cells and the surrounding mesenchymal tissue. The delayed axonal sorting and hypomyelination throughout the peripheral nervous system of claw paw (clp) mutant mice suggest that the clp gene product is critical for these interactions. Here we identify the clp mutation as a 225-bp insertion in the Lgi4 gene. Lgi4 encodes a secreted and glycosylated leucine-rich repeat protein and is expressed in Schwann cells. The clp mutation affects Lgi4 mRNA splicing, resulting in a mutant protein that is retained in the cell. Additionally, siRNA-mediated downregulation of Lgi4 in wild-type neuron-Schwann cell cocultures inhibits myelination, whereas exogenous Lgi4 restores myelination in clp/clp cultures. Thus, the abnormalities observed in clp mice are attributable to the loss of Lgi4 function, and they identify Lgi4 as a new component of Schwann cell signaling pathway(s) that controls axon segregation and myelin formation.
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Affiliation(s)
- John R Bermingham
- McLaughlin Research Institute, 1520 23rd Street South, Great Falls, Montana 59405, USA.
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Darbas A, Jaegle M, Walbeehm E, van den Burg H, Driegen S, Broos L, Uyl M, Visser P, Grosveld F, Meijer D. Cell autonomy of the mouse claw paw mutation. Dev Biol 2004; 272:470-82. [PMID: 15282162 DOI: 10.1016/j.ydbio.2004.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Revised: 05/21/2004] [Accepted: 05/21/2004] [Indexed: 01/13/2023]
Abstract
Mice homozygous for the autosomal recessive mutation claw paw (clp) are characterized by limb posture abnormalities and congenital hypomyelination, with delayed onset of myelination of the peripheral nervous system but not the central nervous system. Although this combination of limb and peripheral nerve abnormalities in clp/clp mice might suggest a common neurogenic origin of the syndrome, it is not clear whether the clp gene acts primarily in the neurone, the Schwann cell or both. In the work described here, we address this question of cell autonomy of the clp mutation through reciprocal nerve grafting experiments between wild-type and clp/clp animals. Our results demonstrate that the clp mutation affects the Schwann cell compartment and possibly also the neuronal compartment. These data suggest that the clp gene product is expressed in Schwann cells as well as neurones and is likely to be involved in direct axon--Schwann cell interactions. Within the Schwann cell, clp affects a myelin-related signaling pathway that regulates periaxin and Krox-20 expression, but not Oct-6.
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Affiliation(s)
- Aysel Darbas
- Department of Cell Biology and Genetics, ErasmusMC, Erasmus University Medical Center, 3000DR Rotterdam, Netherlands
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Abstract
Efficient and rapid propagation of action potentials in myelinated axons depends on the molecular specialization of the nodes of Ranvier. The nodal region is organized into several distinct domains, each of which contains a unique set of ion channels, cell-adhesion molecules and cytoplasmic adaptor proteins. Voltage-gated Na+ channels - which are concentrated at the nodes - are separated from K+ channels - which are clustered at the juxtaparanodal region - by a specialized axoglial contact that is formed between the axon and the myelinating cell at the paranodes. This local differentiation of myelinated axons is tightly regulated by oligodendrocytes and myelinating Schwann cells, and is achieved through complex mechanisms that are used by another specialized cell-cell contact - the synapse.
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Affiliation(s)
- Sebastian Poliak
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
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Abstract
The entire length of myelinated axons is organized into a series of polarized domains that center around nodes of Ranvier. These domains, which are crucial for normal saltatory conduction, consist of distinct multiprotein complexes of cell adhesion molecules, ion channels, and scaffolding molecules; they also differ in their diameter, organelle content, and rates of axonal transport. Juxtacrine signals from myelinating glia direct their sequential assembly. The composition, mechanisms of assembly, and function of these molecular domains will be reviewed. I also discuss similarities of this domain organization to that of polarized epithelia and present emerging evidence that disorders of domain organization and function contribute to the axonopathies of myelin and other neurologic disorders.
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Affiliation(s)
- James L Salzer
- Department of Cell Biology and Neurology, Program in Molecular Neurobiology, Skirball Institute of Biomedical Research, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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Abstract
Myelinated axons are organized into specific domains as the result of interactions with glial cells. Recently, distinct protein complexes of cell adhesion molecules, Na(+) channels and ankyrin G at the nodes, Caspr and contactin in the paranodes, and K(+) channels and Caspr2 in the juxtaparanodal region have been identified, and new insights into the role of the paranodal junctions in the organization of these domains have emerged.
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Affiliation(s)
- E Peles
- Department of Molecular Cell Biology, The Weizmann Institute of Science, 76100, Rehovot, Israel.
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Rasband MN, Peles E, Trimmer JS, Levinson SR, Lux SE, Shrager P. Dependence of nodal sodium channel clustering on paranodal axoglial contact in the developing CNS. J Neurosci 1999; 19:7516-28. [PMID: 10460258 PMCID: PMC6782503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
Na(+) channel clustering at nodes of Ranvier in the developing rat optic nerve was analyzed to determine mechanisms of localization, including the possible requirement for glial contact in vivo. Immunofluorescence labeling for myelin-associated glycoprotein and for the protein Caspr, a component of axoglial junctions, indicated that oligodendrocytes were present, and paranodal structures formed, as early as postnatal day 7 (P7). However, the first Na(+) channel clusters were not seen until P9. Most of these were broad, and all were excluded from paranodal regions of axoglial contact. The number of detected Na(+) channel clusters increased rapidly from P12 to P22. During this same period, conduction velocity increased sharply, and Na(+) channel clusters became much more focal. To test further whether oligodendrocyte contact directly influences Na(+) channel distributions, nodes of Ranvier in the hypomyelinating mouse Shiverer were examined. This mutant has oligodendrocyte-ensheathed axons but lacks compact myelin and normal axoglial junctions. During development Na(+) channel clusters in Shiverer mice were reduced in numbers and were in aberrant locations. The subcellular location of Caspr was disrupted, and nerve conduction properties remained immature. These results indicate that in vivo, Na(+) channel clustering at nodes depends not only on the presence of oligodendrocytes but also on specific axoglial contact at paranodal junctions. In rats, ankyrin-3/G, a cytoskeletal protein implicated in Na(+) channel clustering, was detected before Na(+) channel immunoreactivity but extended into paranodes in non-nodal distributions. In Shiverer, ankyrin-3/G labeling was abnormal, suggesting that its localization also depends on axoglial contact.
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Affiliation(s)
- M N Rasband
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA
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