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Markusson S, Raasakka A, Schröder M, Sograte-Idrissi S, Rahimi AM, Asadpour O, Körner H, Lodygin D, Eichel-Vogel MA, Chowdhury R, Sutinen A, Muruganandam G, Iyer M, Cooper MH, Weigel MK, Ambiel N, Werner HB, Zuchero JB, Opazo F, Kursula P. Nanobodies against the myelin enzyme CNPase as tools for structural and functional studies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.25.595513. [PMID: 38826303 PMCID: PMC11142274 DOI: 10.1101/2024.05.25.595513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) is an abundant constituent of central nervous system non-compact myelin, frequently used as a marker antigen for myelinating cells. The catalytic activity of CNPase, the 3'-hydrolysis of 2',3'-cyclic nucleotides, is well characterised in vitro, but the in vivo function of CNPase remains unclear. CNPase interacts with the actin cytoskeleton to counteract the developmental closure of cytoplasmic channels that travel through compact myelin; its enzymatic activity may be involved in adenosine metabolism and RNA degradation. We developed a set of high-affinity nanobodies recognizing the phosphodiesterase domain of CNPase, and the crystal structures of each complex show that the five nanobodies have distinct epitopes. One of the nanobodies bound deep into the CNPase active site and acted as an inhibitor. Moreover, the nanobodies were characterised in imaging applications and as intrabodies, expressed in mammalian cells, such as primary oligodendrocytes. Fluorescently labelled nanobodies functioned in imaging of teased nerve fibers and whole brain tissue sections, as well as super-resolution microscopy. These anti-CNPase nanobodies provide new tools for structural and functional biology of myelination, including high-resolution imaging of nerve tissue.
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Affiliation(s)
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Neurosurgery Department, Stanford University School of Medicine, Stanford, CA, USA
| | - Marcel Schröder
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Shama Sograte-Idrissi
- Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Amir Mohammad Rahimi
- Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Ommolbanin Asadpour
- Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Henrike Körner
- Department for Neuroimmunology and Multiple Sclerosis Research, University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Dmitri Lodygin
- Department for Neuroimmunology and Multiple Sclerosis Research, University of Göttingen Medical Center, 37075 Göttingen, Germany
| | - Maria A. Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, D-37075 Göttingen, Germany
| | - Risha Chowdhury
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Aleksi Sutinen
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
| | - Gopinath Muruganandam
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Department of Bioengineering Sciences, Structural Biology Brussels, Vrije Universiteit Brussel, Brussel, Belgium
| | - Manasi Iyer
- Neurosurgery Department, Stanford University School of Medicine, Stanford, CA, USA
| | - Madeline H. Cooper
- Neurosurgery Department, Stanford University School of Medicine, Stanford, CA, USA
| | - Maya K. Weigel
- Neurosurgery Department, Stanford University School of Medicine, Stanford, CA, USA
| | - Nicholas Ambiel
- Neurosurgery Department, Stanford University School of Medicine, Stanford, CA, USA
| | - Hauke B. Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, D-37075 Göttingen, Germany
| | - J. Bradley Zuchero
- Neurosurgery Department, Stanford University School of Medicine, Stanford, CA, USA
| | - Felipe Opazo
- Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany
- NanoTag Biotechnologies GmbH, 37079 Göttingen, Germany
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Finland
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2
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Wu L, Lambert JD. Clade-specific genes and the evolutionary origin of novelty; new tools in the toolkit. Semin Cell Dev Biol 2023; 145:52-59. [PMID: 35659164 DOI: 10.1016/j.semcdb.2022.05.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 04/27/2022] [Accepted: 05/25/2022] [Indexed: 10/18/2022]
Abstract
Clade-specific (a.k.a. lineage-specific) genes are very common and found at all taxonomic levels and in all clades examined. They can arise by duplication of previously existing genes, which can involve partial truncations or combinations with other protein domains or regulatory sequences. They can also evolve de novo from non-coding sequences, leading to potentially truly novel protein domains. Finally, since clade-specific genes are generally defined by lack of sequence homology with other proteins, they can also arise by sequence evolution that is rapid enough that previous sequence homology can no longer be detected. In such cases, where the rapid evolution is followed by constraint, we consider them to be ontologically non-novel but likely novel at a functional level. In general, clade-specific genes have received less attention from biologists but there are increasing numbers of fascinating examples of their roles in important traits. Here we review some selected recent examples, and argue that attention to clade-specific genes is an important corrective to the focus on the conserved developmental regulatory toolkit that has been the habit of evo-devo as a field. Finally, we discuss questions that arise about the evolution of clade-specific genes, and how these might be addressed by future studies. We highlight the hypothesis that clade-specific genes are more likely to be involved in synapomorphies that arose in the stem group where they appeared, compared to other genes.
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Affiliation(s)
- Longjun Wu
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - J David Lambert
- Department of Biology, University of Rochester, Rochester, NY 14627, USA.
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3
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Martens AK, Erwig M, Patzig J, Fledrich R, Füchtbauer EM, Werner HB. Targeted inactivation of the Septin2 and Septin9 genes in myelinating Schwann cells of mice. Cytoskeleton (Hoboken) 2023; 80:290-302. [PMID: 36378242 DOI: 10.1002/cm.21736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022]
Abstract
The formation of axon-enwrapping myelin sheaths by oligodendrocytes in the central nervous system involves the assembly of a scaffolding septin filament comprised of the subunits SEPTIN2, SEPTIN4, SEPTIN7 and SEPTIN8. Conversely, in the peripheral nervous system (PNS), myelin is synthesized by a different cell type termed Schwann cells, and it remained unknown if septins also assemble as a multimer in PNS myelin. According to prior proteome analysis, PNS myelin comprises the subunits SEPTIN2, SEPTIN7, SEPTIN8, SEPTIN9, and SEPTIN11, which localize to the paranodal and abaxonal myelin subcompartments. Here, we use the Cre/loxP-system to delete the Septin9-gene specifically in Schwann cells, causing a markedly reduced abundance of SEPTIN9 in sciatic nerves, implying that Schwann cells are the main cell type expressing SEPTIN9 in the nerve. However, Septin9-deficiency in Schwann cells did not affect the abundance or localization of other septin subunits. In contrast, when deleting the Septin2-gene in Schwann cells the abundance of all relevant septin subunits was markedly reduced, including SEPTIN9. Notably, we did not find evidence that deleting Septin2 or Septin9 in Schwann cells impairs myelin biogenesis, nerve conduction velocity or motor/sensory capabilities, at least at the assessed timepoints. Our data thus show that SEPTIN2 but not SEPTIN9 is required for the formation or stabilization of a septin multimer in PNS myelin in vivo; however, its functional relevance remains to be established.
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Affiliation(s)
- Ann-Kristin Martens
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Michelle Erwig
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | | | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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4
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Steyer AM, Buscham TJ, Lorenz C, Hümmert S, Eichel-Vogel MA, Schadt LC, Edgar JM, Köster S, Möbius W, Nave KA, Werner HB. Focused ion beam-scanning electron microscopy links pathological myelin outfoldings to axonal changes in mice lacking Plp1 or Mag. Glia 2023; 71:509-523. [PMID: 36354016 DOI: 10.1002/glia.24290] [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: 07/11/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022]
Abstract
Healthy myelin sheaths consist of multiple compacted membrane layers closely encasing the underlying axon. The ultrastructure of CNS myelin requires specialized structural myelin proteins, including the transmembrane-tetraspan proteolipid protein (PLP) and the Ig-CAM myelin-associated glycoprotein (MAG). To better understand their functional relevance, we asked to what extent the axon/myelin-units display similar morphological changes if PLP or MAG are lacking. We thus used focused ion beam-scanning electron microscopy (FIB-SEM) to re-investigate axon/myelin-units side-by-side in Plp- and Mag-null mutant mice. By three-dimensional reconstruction and morphometric analyses, pathological myelin outfoldings extend up to 10 μm longitudinally along myelinated axons in both models. More than half of all assessed outfoldings emerge from internodal myelin. Unexpectedly, three-dimensional reconstructions demonstrated that both models displayed complex axonal pathology underneath the myelin outfoldings, including axonal sprouting. Axonal anastomosing was additionally observed in Plp-null mutant mice. Importantly, normal-appearing axon/myelin-units displayed significantly increased axonal diameters in both models according to quantitative assessment of electron micrographs. These results imply that healthy CNS myelin sheaths facilitate normal axonal diameters and shape, a function that is impaired when structural myelin proteins PLP or MAG are lacking.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Charlotta Lorenz
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Sophie Hümmert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Leonie C Schadt
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah Köster
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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5
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Sanchez‐Roige S, Barnes SA, Mallari J, Wood R, Polesskaya O, Palmer AA. A mutant allele of glycoprotein M6-B (Gpm6b) facilitates behavioral flexibility but increases delay discounting. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12800. [PMID: 35243767 PMCID: PMC9211103 DOI: 10.1111/gbb.12800] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 11/26/2022]
Abstract
The neuronal membrane glycoprotein M6B (Gpm6b) gene encodes a membrane glycoprotein that belongs to the proteolipid protein family, and is enriched in neurons, oligodendrocytes, and subset of astrocytes in the central nervous system. GPM6B is thought to play a role in neuronal differentiation, myelination, and inactivation of the serotonin transporter via internalization. Recent human genome-wide association studies (GWAS) have implicated membrane glycoproteins (both GPM6B and GPM6A) in the regulation of traits relevant to psychiatric disorders, including neuroticism, depressed affect, and delay discounting. Mouse studies have implicated Gpm6b in sensorimotor gating and regulation of serotonergic signaling. We used CRISPR to create a mutant Glycoprotein M6B (Gpm6b) allele on a C57BL/6J mouse background. Because Gpm6b is located on the X chromosome, we focused on male Gpm6b mutant mice and their wild-type littermates (WT) in two behavioral tests that measured aspects of impulsive or flexible decision-making. We found that Gpm6b deletion caused deficits in a delay discounting task. In contrast, reward sensitivity was enhanced thereby facilitating behavioral flexibility and improving performance in the probabilistic reversal learning task. Taken together these data further delineate the role of Gpm6b in decision making behaviors that are relevant to multiple psychiatric disorders.
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Affiliation(s)
- Sandra Sanchez‐Roige
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA,Department of Medicine, Division of Genetic MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Samuel A. Barnes
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Jazlene Mallari
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Rebecca Wood
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Oksana Polesskaya
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Abraham A. Palmer
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA,Institute for Genomic MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
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6
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Siems SB, Jahn O, Hoodless LJ, Jung RB, Hesse D, Möbius W, Czopka T, Werner HB. Proteome Profile of Myelin in the Zebrafish Brain. Front Cell Dev Biol 2021; 9:640169. [PMID: 33898427 PMCID: PMC8060510 DOI: 10.3389/fcell.2021.640169] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
The velocity of nerve conduction along vertebrate axons depends on their ensheathment with myelin. Myelin membranes comprise specialized proteins well characterized in mice. Much less is known about the protein composition of myelin in non-mammalian species. Here, we assess the proteome of myelin biochemically purified from the brains of adult zebrafish (Danio rerio), considering its increasing popularity as model organism for myelin biology. Combining gel-based and gel-free proteomic approaches, we identified > 1,000 proteins in purified zebrafish myelin, including all known constituents. By mass spectrometric quantification, the predominant Ig-CAM myelin protein zero (MPZ/P0), myelin basic protein (MBP), and the short-chain dehydrogenase 36K constitute 12%, 8%, and 6% of the total myelin protein, respectively. Comparison with previously established mRNA-abundance profiles shows that expression of many myelin-related transcripts coincides with the maturation of zebrafish oligodendrocytes. Zebrafish myelin comprises several proteins that are not present in mice, including 36K, CLDNK, and ZWI. However, a surprisingly large number of ortholog proteins is present in myelin of both species, indicating partial evolutionary preservation of its constituents. Yet, the relative abundance of CNS myelin proteins can differ markedly as exemplified by the complement inhibitor CD59 that constitutes 5% of the total zebrafish myelin protein but is a low-abundant myelin component in mice. Using novel transgenic reporter constructs and cryo-immuno electron microscopy, we confirm the incorporation of CD59 into myelin sheaths. These data provide the first proteome resource of zebrafish CNS myelin and demonstrate both similarities and heterogeneity of myelin composition between teleost fish and rodents.
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Affiliation(s)
- Sophie B Siems
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Laura J Hoodless
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Dörte Hesse
- Proteomics Group, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Tim Czopka
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany
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7
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Abstract
Myelination of axons provides the structural basis for rapid saltatory impulse propagation along vertebrate fiber tracts, a well-established neurophysiological concept. However, myelinating oligodendrocytes and Schwann cells serve additional functions in neuronal energy metabolism that are remarkably similar to those of axon-ensheathing glial cells in unmyelinated invertebrates. Here we discuss myelin evolution and physiological glial functions, beginning with the role of ensheathing glia in preventing ephaptic coupling, axoglial metabolic support, and eliminating oxidative radicals. In both vertebrates and invertebrates, axoglial interactions are bidirectional, serving to regulate cell fate, nerve conduction, and behavioral performance. One key step in the evolution of compact myelin in the vertebrate lineage was the emergence of the open reading frame for myelin basic protein within another gene. Several other proteins were neofunctionalized as myelin constituents and help maintain a healthy nervous system. Myelination in vertebrates became a major prerequisite of inhabiting new ecological niches.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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8
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Möbius W, Hümmert S, Ruhwedel T, Kuzirian A, Gould R. New Species Can Broaden Myelin Research: Suitability of Little Skate, Leucoraja erinacea. Life (Basel) 2021; 11:136. [PMID: 33670172 PMCID: PMC7916940 DOI: 10.3390/life11020136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/02/2021] [Accepted: 02/06/2021] [Indexed: 02/06/2023] Open
Abstract
Although myelinated nervous systems are shared among 60,000 jawed vertebrates, studies aimed at understanding myelination have focused more and more on mice and zebrafish. To obtain a broader understanding of the myelination process, we examined the little skate, Leucoraja erinacea. The reasons behind initiating studies at this time include: the desire to study a species belonging to an out group of other jawed vertebrates; using a species with embryos accessible throughout development; the availability of genome sequences; and the likelihood that mammalian antibodies recognize homologs in the chosen species. We report that the morphological features of myelination in a skate hatchling, a stage that supports complex behavioral repertoires needed for survival, are highly similar in terms of: appearances of myelinating oligodendrocytes (CNS) and Schwann cells (PNS); the way their levels of myelination conform to axon caliber; and their identity in terms of nodal and paranodal specializations. These features provide a core for further studies to determine: axon-myelinating cell communication; the structures of the proteins and lipids upon which myelinated fibers are formed; the pathways used to transport these molecules to sites of myelin assembly and maintenance; and the gene regulatory networks that control their expressions.
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Affiliation(s)
- Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, 37075 Göttingen, Germany; (W.M.); (S.H.); (T.R.)
- Cluster of Excellence Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC), University of Göttingen, 37073 Göttingen, Germany
| | - Sophie Hümmert
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, 37075 Göttingen, Germany; (W.M.); (S.H.); (T.R.)
| | - Torben Ruhwedel
- Electron Microscopy Core Unit, Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, 37075 Göttingen, Germany; (W.M.); (S.H.); (T.R.)
| | - Alan Kuzirian
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02540, USA;
| | - Robert Gould
- Whitman Science Center, Marin Biological Laboratory, Woods Hole, MA 02540, USA
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9
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Structural myelin defects are associated with low axonal ATP levels but rapid recovery from energy deprivation in a mouse model of spastic paraplegia. PLoS Biol 2020; 18:e3000943. [PMID: 33196637 PMCID: PMC7704050 DOI: 10.1371/journal.pbio.3000943] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 11/30/2020] [Accepted: 10/22/2020] [Indexed: 11/19/2022] Open
Abstract
In several neurodegenerative disorders, axonal pathology may originate from impaired oligodendrocyte-to-axon support of energy substrates. We previously established transgenic mice that allow measuring axonal ATP levels in electrically active optic nerves. Here, we utilize this technique to explore axonal ATP dynamics in the Plpnull/y mouse model of spastic paraplegia. Optic nerves from Plpnull/y mice exhibited lower and more variable basal axonal ATP levels and reduced compound action potential (CAP) amplitudes, providing a missing link between axonal pathology and a role of oligodendrocytes in brain energy metabolism. Surprisingly, when Plpnull/y optic nerves are challenged with transient glucose deprivation, both ATP levels and CAP decline slower, but recover faster upon reperfusion of glucose. Structurally, myelin sheaths display an increased frequency of cytosolic channels comprising glucose and monocarboxylate transporters, possibly facilitating accessibility of energy substrates to the axon. These data imply that complex metabolic alterations of the axon–myelin unit contribute to the phenotype of Plpnull/y mice. Imaging of ATP dynamics in the optic nerve axons of mice lacking the major myelin protein PLP (a model of spastic paraplegia) reveals complex alterations in the metabolic interaction between oligodendrocytes and axons, associated with structural deficits of myelin.
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10
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Jahn O, Siems SB, Kusch K, Hesse D, Jung RB, Liepold T, Uecker M, Sun T, Werner HB. The CNS Myelin Proteome: Deep Profile and Persistence After Post-mortem Delay. Front Cell Neurosci 2020; 14:239. [PMID: 32973451 PMCID: PMC7466725 DOI: 10.3389/fncel.2020.00239] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/07/2020] [Indexed: 12/14/2022] Open
Abstract
Myelin membranes are dominated by lipids while the complexity of their protein composition has long been considered to be low. However, numerous additional myelin proteins have been identified since. Here we revisit the proteome of myelin biochemically purified from the brains of healthy c56Bl/6N-mice utilizing complementary proteomic approaches for deep qualitative and quantitative coverage. By gel-free, label-free mass spectrometry, the most abundant myelin proteins PLP, MBP, CNP, and MOG constitute 38, 30, 5, and 1% of the total myelin protein, respectively. The relative abundance of myelin proteins displays a dynamic range of over four orders of magnitude, implying that PLP and MBP have overshadowed less abundant myelin constituents in initial gel-based approaches. By comparisons with published datasets we evaluate to which degree the CNS myelin proteome correlates with the mRNA and protein abundance profiles of myelin and oligodendrocytes. Notably, the myelin proteome displays only minor changes if assessed after a post-mortem delay of 6 h. These data provide the most comprehensive proteome resource of CNS myelin so far and a basis for addressing proteomic heterogeneity of myelin in mouse models and human patients with white matter disorders.
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Affiliation(s)
- Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sophie B. Siems
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Dörte Hesse
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ramona B. Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Thomas Liepold
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Marina Uecker
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hauke B. Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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11
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Igarashi M, Honda A, Kawasaki A, Nozumi M. Neuronal Signaling Involved in Neuronal Polarization and Growth: Lipid Rafts and Phosphorylation. Front Mol Neurosci 2020; 13:150. [PMID: 32922262 PMCID: PMC7456915 DOI: 10.3389/fnmol.2020.00150] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/16/2020] [Indexed: 12/17/2022] Open
Abstract
Neuronal polarization and growth are developmental processes that occur during neuronal cell differentiation. The molecular signaling mechanisms involved in these events in in vivo mammalian brain remain unclear. Also, cellular events of the neuronal polarization process within a given neuron are thought to be constituted of many independent intracellular signal transduction pathways (the "tug-of-war" model). However, in vivo results suggest that such pathways should be cooperative with one another among a given group of neurons in a region of the brain. Lipid rafts, specific membrane domains with low fluidity, are candidates for the hotspots of such intracellular signaling. Among the signals reported to be involved in polarization, a number are thought to be present or translocated to the lipid rafts in response to extracellular signals. As part of our analysis, we discuss how such novel molecular mechanisms are combined for effective regulation of neuronal polarization and growth, focusing on the significance of the lipid rafts, including results based on recently introduced methods.
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Affiliation(s)
- Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Atsuko Honda
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Motohiro Nozumi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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12
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Malik P, Muthusamy K, Mankad K, Shroff M, Sudhakar S. Solving the hypomyelination conundrum - Imaging perspectives. Eur J Paediatr Neurol 2020; 27:9-24. [PMID: 32418752 DOI: 10.1016/j.ejpn.2020.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 03/25/2020] [Accepted: 04/14/2020] [Indexed: 11/26/2022]
Abstract
Hypomyelinating Leukodystrophies (HLDs) are a genetically heterogeneous, clinically overlapping group of disorders with the unifying MR imaging appearance of myelin deficit in the brain. In fact, it is the MRI phenotype that typically raises the diagnostic suspicion in this single largest group of undiagnosed leukodystrophies and guides gene testing for confirmation. This article reviews the neurobiology of myelination, focussing on the complex interplay of molecular genetic pathways and presents a practical clinico-radiological diagnostic algorithm based on the neuroimaging patterns of the common hypomyelinating disorders. The authors also address the current controversies about the definition and use of the term 'hypomyelination'.
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13
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Steyer AM, Ruhwedel T, Nardis C, Werner HB, Nave KA, Möbius W. Pathology of myelinated axons in the PLP-deficient mouse model of spastic paraplegia type 2 revealed by volume imaging using focused ion beam-scanning electron microscopy. J Struct Biol 2020; 210:107492. [PMID: 32156581 PMCID: PMC7196930 DOI: 10.1016/j.jsb.2020.107492] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/28/2020] [Accepted: 03/06/2020] [Indexed: 11/26/2022]
Abstract
Advances in electron microscopy including improved imaging techniques and state-of-the-art detectors facilitate imaging of larger tissue volumes with electron microscopic resolution. In combination with genetic tools for the generation of mouse mutants this allows assessing the three-dimensional (3D) characteristics of pathological features in disease models. Here we revisited the axonal pathology in the central nervous system of a mouse model of spastic paraplegia type 2, the Plp-/Y mouse. Although PLP is a bona fide myelin protein, the major hallmark of the disease in both SPG2 patients and mouse models are axonal swellings comprising accumulations of numerous organelles including mitochondria, gradually leading to irreversible axonal loss. To assess the number and morphology of axonal mitochondria and the overall myelin preservation we evaluated two sample preparation techniques, chemical fixation or high-pressure freezing and freeze substitution, with respect to the objective of 3D visualization. Both methods allowed visualizing distribution and morphological details of axonal mitochondria. In Plp-/Y mice the number of mitochondria is 2-fold increased along the entire axonal length. Mitochondria are also found in the excessive organelle accumulations within axonal swellings. In addition, organelle accumulations were detected within the myelin sheath and the inner tongue. We find that 3D electron microscopy is required for a comprehensive understanding of the size, content and frequency of axonal swellings, the hallmarks of axonal pathology.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Christos Nardis
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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14
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Sato M, Arita M, Kawashima T. Uncovering Ecdysozoa-specific Sphingomyelin Synthase by Phylogenetic Analysis of Metazoan Sequences. Zoolog Sci 2019; 36:316-321. [PMID: 34664902 DOI: 10.2108/zs180168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 03/01/2019] [Indexed: 11/17/2022]
Abstract
Sphingomyelin (SM) is a membrane phospholipid that is widely distributed in Metazoa; it is the major constituent of myelin sheaths in vertebrates. In mammals, two genes (SMS1 and SMS2) are responsible for its synthesis. No SM-producing genes have been clearly identified in insects and crustaceans (Ecdysozoa) despite the presence of a myelin sheath-like structure in shrimps. Since the rapid transmission of electrical signals requires the use of an insulating material in the nerve, it is possible that the convergent evolution of enzymes to synthesize the insulating compounds for the nervous system also occurred in animals other than vertebrates. Our exhaustive phylogenetic search for metazoan SM synthase identified an Ecdysozoa-specific SM synthase candidate, SMSe, which is absent in Drosophila and Lophotrochozoa. All Ecdysozoa lack the homolog of myelin basic- and proteolipid proteins present in mammals. We propose an evolutionary path of SM synthase and discuss the origin of the myelin structure in Metazoa.
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Affiliation(s)
- Mitsuharu Sato
- National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan,
| | - Masanori Arita
- National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.,RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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15
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Lüders KA, Nessler S, Kusch K, Patzig J, Jung RB, Möbius W, Nave KA, Werner HB. Maintenance of high proteolipid protein level in adult central nervous system myelin is required to preserve the integrity of myelin and axons. Glia 2019; 67:634-649. [PMID: 30637801 DOI: 10.1002/glia.23549] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/24/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
Abstract
Proteolipid protein (PLP) is the most abundant integral membrane protein in central nervous system (CNS) myelin. Expression of the Plp-gene in oligodendrocytes is not essential for the biosynthesis of myelin membranes but required to prevent axonal pathology. This raises the question whether the exceptionally high level of PLP in myelin is required later in life, or whether high-level PLP expression becomes dispensable once myelin has been assembled. Both models require a better understanding of the turnover of PLP in myelin in vivo. Thus, we generated and characterized a novel line of tamoxifen-inducible Plp-mutant mice that allowed us to determine the rate of PLP turnover after developmental myelination has been completed, and to assess the possible impact of gradually decreasing amounts of PLP for myelin and axonal integrity. We found that 6 months after targeting the Plp-gene the abundance of PLP in CNS myelin was about halved, probably reflecting that myelin is slowly turned over in the adult brain. Importantly, this reduction by 50% was sufficient to cause the entire spectrum of neuropathological changes previously associated with the developmental lack of PLP, including myelin outfoldings, lamellae splittings, and axonal spheroids. In comparison to axonopathy and gliosis, the infiltration of cytotoxic T-cells was temporally delayed, suggesting a corresponding chronology also in the genetic disorders of PLP-deficiency. High-level abundance of PLP in myelin throughout adult life emerges as a requirement for the preservation of white matter integrity.
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Affiliation(s)
- Katja A Lüders
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, Göttingen, Germany
| | - Stefan Nessler
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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16
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Erwig MS, Hesse D, Jung RB, Uecker M, Kusch K, Tenzer S, Jahn O, Werner HB. Myelin: Methods for Purification and Proteome Analysis. Methods Mol Biol 2019; 1936:37-63. [PMID: 30820892 DOI: 10.1007/978-1-4939-9072-6_3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Molecular characterization of myelin is a prerequisite for understanding the normal structure of the axon/myelin-unit in the healthy nervous system and abnormalities in myelin-related disorders. However, reliable molecular profiles necessitate very pure myelin membranes, in particular when considering the power of highly sensitive "omics"-data acquisition methods. Here, we recapitulate the history and recent applications of myelin purification. We then provide our laboratory protocols for the biochemical isolation of a highly pure myelin-enriched fraction from mouse brains and for its proteomic analysis. We also supply methodological modifications when investigating posttranslational modifications, RNA, or myelin from peripheral nerves. Notably, technical advancements in solubilizing myelin are beneficial for gel-based and gel-free myelin proteome analyses. We conclude this article by exemplifying the exceptional power of label-free proteomics in the mass-spectrometric quantification of myelin proteins.
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Affiliation(s)
- Michelle S Erwig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Dörte Hesse
- Proteomics Group, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Marina Uecker
- Proteomics Group, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Stefan Tenzer
- Institute of Immunology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Goettingen, Germany.
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany.
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17
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IGARASHI M. Molecular basis of the functions of the mammalian neuronal growth cone revealed using new methods. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2019; 95:358-377. [PMID: 31406059 PMCID: PMC6766448 DOI: 10.2183/pjab.95.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/26/2019] [Indexed: 05/25/2023]
Abstract
The neuronal growth cone is a highly motile, specialized structure for extending neuronal processes. This structure is essential for nerve growth, axon pathfinding, and accurate synaptogenesis. Growth cones are important not only during development but also for plasticity-dependent synaptogenesis and neuronal circuit rearrangement following neural injury in the mature brain. However, the molecular details of mammalian growth cone function are poorly understood. This review examines molecular findings on the function of the growth cone as a result of the introduction of novel methods such superresolution microscopy and (phospho)proteomics. These results increase the scope of our understating of the molecular mechanisms of growth cone behavior in the mammalian brain.
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Affiliation(s)
- Michihiro IGARASHI
- Department of Neurochemistry and Molecular Cell Biology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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18
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Zhang X, Xie H, Chang P, Zhao H, Xia Y, Zhang L, Guo X, Huang C, Yan F, Hu L, Lin C, Li Y, Xiong Z, Wang X, Li G, Deng L, Wang S, Tao L. Glycoprotein M6B Interacts with TβRI to Activate TGF-β-Smad2/3 Signaling and Promote Smooth Muscle Cell Differentiation. Stem Cells 2018; 37:190-201. [PMID: 30372567 PMCID: PMC7379588 DOI: 10.1002/stem.2938] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 10/07/2018] [Accepted: 10/08/2018] [Indexed: 01/01/2023]
Abstract
Smooth muscle cells (SMCs), which form the walls of blood vessels, play an important role in vascular development and the pathogenic process of vascular remodeling. However, the molecular mechanisms governing SMC differentiation remain poorly understood. Glycoprotein M6B (GPM6B) is a four-transmembrane protein that belongs to the proteolipid protein family and is widely expressed in neurons, oligodendrocytes, and astrocytes. Previous studies have revealed that GPM6B plays a role in neuronal differentiation, myelination, and osteoblast differentiation. In the present study, we found that the GPM6B gene and protein expression levels were significantly upregulated during transforming growth factor-β1 (TGF-β1)-induced SMC differentiation. The knockdown of GPM6B resulted in the downregulation of SMC-specific marker expression and repressed the activation of Smad2/3 signaling. Moreover, GPM6B regulates SMC Differentiation by Controlling TGF-β-Smad2/3 Signaling. Furthermore, we demonstrated that similar to p-Smad2/3, GPM6B was profoundly expressed and coexpressed with SMC differentiation markers in embryonic SMCs. Moreover, GPM6B can regulate the tightness between TβRI, TβRII, or Smad2/3 by directly binding to TβRI to activate Smad2/3 signaling during SMC differentiation, and activation of TGF-β-Smad2/3 signaling also facilitate the expression of GPM6B. Taken together, these findings demonstrate that GPM6B plays a crucial role in SMC differentiation and regulates SMC differentiation through the activation of TGF-β-Smad2/3 signaling via direct interactions with TβRI. This finding indicates that GPM6B is a potential target for deriving SMCs from stem cells in cardiovascular regenerative medicine. Stem Cells 2018 Stem Cells 2019;37:190-201.
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Affiliation(s)
- Xiaomeng Zhang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Huaning Xie
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Pan Chang
- Central Laboratory, Second Affiliated Hospital, Xi'an Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Huishou Zhao
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Yunlong Xia
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Ling Zhang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Xiong Guo
- Department of Cardiology, Hospital of People's Liberation Army, Golmud, Qinghai, People's Republic of China
| | - Chong Huang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Feng Yan
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Lang Hu
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Chen Lin
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Yueyang Li
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Zhenyu Xiong
- Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Xiong Wang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Guohua Li
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Longxiang Deng
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Shan Wang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Ling Tao
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China
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19
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Garcia-Pradas L, Gleiser C, Wizenmann A, Wolburg H, Mack AF. Glial Cells in the Fish Retinal Nerve Fiber Layer Form Tight Junctions, Separating and Surrounding Axons. Front Mol Neurosci 2018; 11:367. [PMID: 30364233 PMCID: PMC6192225 DOI: 10.3389/fnmol.2018.00367] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/18/2018] [Indexed: 02/01/2023] Open
Abstract
In the retina of teleost fish, cell addition continues throughout life involving proliferation and axonal growth. To study how this is achieved in a fully functioning retina, we investigated the nerve fiber layer (NFL) of the cichlid fish Astatotilapia burtoni for components that might regulate the extracellular environment. We hypothesized that growing axons are surrounded by different cell structures than signal conducting axons. Using immunohistochemistry and freeze fracture electron microscopy we found that the endfeet of Müller cells (MCs) expressed aquaporin-4 but not in high densities as in mammals. The presence of this water channel indicates the involvement of MCs in water homeostasis. Remarkably, we discovered conspicuous tight junctions in the retinal NFL. These tight junctions formed branching strands between myelin-like wrappings of ganglion cell axons that differed morphologically from any known myelin, and also an elaborate meshwork on large membrane faces between axons. We speculated that these tight junctions have additional functions than solely facilitating nerve conductance. Immunostainings against the adaptor protein ZO-1 labeled the NFL as did antibodies against the mammalian claudin-1, 3, and 19. Performing PCR analysis, we showed expression of claudin-1, 3, 5a, 5b, 9, 11, and 19 in the fish retina, claudins that typically occur at brain barriers or myelin. We could show by immunostains for doublecortin, a marker for differentiating neurons, that new axons are not surrounded by the myelin-like wrappings but only by the endfeet of MCs. We hypothesize that the tight junctions in the NFL of fish might contribute to the separation of an extracellular space around axons facilitating conductance, from a growth-promoting environment. For a functional test we applied Evans Blue dye to eye cup preparations which showed a retention of the dye in the NFL. This indicates that these remarkable tight junctions can indeed act as a diffusion barrier.
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Affiliation(s)
- Lidia Garcia-Pradas
- Institut für klinische Anatomie und Zellanalytik, Universität Tübingen, Tübingen, Germany
| | - Corinna Gleiser
- Institut für klinische Anatomie und Zellanalytik, Universität Tübingen, Tübingen, Germany
| | - Andrea Wizenmann
- Institut für klinische Anatomie und Zellanalytik, Universität Tübingen, Tübingen, Germany
| | - Hartwig Wolburg
- Institut für Pathologie und Neuropathologie, Universität Tübingen, Tübingen, Germany
| | - Andreas F Mack
- Institut für klinische Anatomie und Zellanalytik, Universität Tübingen, Tübingen, Germany
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20
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Bang ML, Vainshtein A, Yang HJ, Eshed-Eisenbach Y, Devaux J, Werner HB, Peles E. Glial M6B stabilizes the axonal membrane at peripheral nodes of Ranvier. Glia 2018; 66:801-812. [PMID: 29282769 PMCID: PMC5812800 DOI: 10.1002/glia.23285] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/06/2017] [Accepted: 12/11/2017] [Indexed: 12/18/2022]
Abstract
Glycoprotein M6B and the closely related proteolipid protein regulate oligodendrocyte myelination in the central nervous system, but their role in the peripheral nervous system is less clear. Here we report that M6B is located at nodes of Ranvier in peripheral nerves where it stabilizes the nodal axolemma. We show that M6B is co-localized and associates with gliomedin at Schwann cell microvilli that are attached to the nodes. Developmental analysis of sciatic nerves, as well as of myelinating Schwann cells/dorsal root ganglion neurons cultures, revealed that M6B is already present at heminodes, which are considered the precursors of mature nodes of Ranvier. However, in contrast to gliomedin, which accumulates at heminodes with or prior to Na+ channels, we often detected Na+ channel clusters at heminodes without any associated M6B, indicating that it is not required for initial channel clustering. Consistently, nodal cell adhesion molecules (NF186, NrCAM), ion channels (Nav1.2 and Kv7.2), cytoskeletal proteins (AnkG and βIV spectrin), and microvilli components (pERM, syndecan3, gliomedin), are all present at both heminodes and mature nodes of Ranvier in Gpm6b null mice. Using transmission electron microscopy, we show that the absence of M6B results in progressive appearance of nodal protrusions of the nodal axolemma, that are often accompanied by the presence of enlarged mitochondria. Our results reveal that M6B is a Schwann cell microvilli component that preserves the structural integrity of peripheral nodes of Ranvier.
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Affiliation(s)
- Marie L Bang
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Anya Vainshtein
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Hyun-Jeong Yang
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Jerome Devaux
- Aix-Marseille University, CNRS, CRN2M-UMR 7286, Marseille, France
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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21
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Ito Y, Honda A, Igarashi M. Glycoprotein M6a as a signaling transducer in neuronal lipid rafts. Neurosci Res 2018; 128:19-24. [DOI: 10.1016/j.neures.2017.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 02/07/2023]
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22
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23
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Lüders KA, Patzig J, Simons M, Nave KA, Werner HB. Genetic dissection of oligodendroglial and neuronalPlp1function in a novel mouse model of spastic paraplegia type 2. Glia 2017; 65:1762-1776. [DOI: 10.1002/glia.23193] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Katja A. Lüders
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Julia Patzig
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Mikael Simons
- Cellular Neuroscience; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Hauke B. Werner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
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24
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Mittendorf KF, Marinko JT, Hampton CM, Ke Z, Hadziselimovic A, Schlebach JP, Law CL, Li J, Wright ER, Sanders CR, Ohi MD. Peripheral myelin protein 22 alters membrane architecture. SCIENCE ADVANCES 2017; 3:e1700220. [PMID: 28695207 PMCID: PMC5498104 DOI: 10.1126/sciadv.1700220] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/19/2017] [Indexed: 05/10/2023]
Abstract
Peripheral myelin protein 22 (PMP22) is highly expressed in myelinating Schwann cells of the peripheral nervous system. PMP22 genetic alterations cause the most common forms of Charcot-Marie-Tooth disease (CMTD), which is characterized by severe dysmyelination in the peripheral nerves. However, the functions of PMP22 in Schwann cell membranes remain unclear. We demonstrate that reconstitution of purified PMP22 into lipid vesicles results in the formation of compressed and cylindrically wrapped protein-lipid vesicles that share common organizational traits with compact myelin of peripheral nerves in vivo. The formation of these myelin-like assemblies depends on the lipid-to-PMP22 ratio, as well as on the PMP22 extracellular loops. Formation of the myelin-like assemblies is disrupted by a CMTD-causing mutation. This study provides both a biochemical assay for PMP22 function and evidence that PMP22 directly contributes to membrane organization in compact myelin.
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Affiliation(s)
- Kathleen F. Mittendorf
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Justin T. Marinko
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Cheri M. Hampton
- Division of Infectious Disease, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zunlong Ke
- Division of Infectious Disease, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Arina Hadziselimovic
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Jonathan P. Schlebach
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Cheryl L. Law
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Jun Li
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Elizabeth R. Wright
- Division of Infectious Disease, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Charles R. Sanders
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Corresponding author. (M.D.O.); (C.R.S.)
| | - Melanie D. Ohi
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
- Corresponding author. (M.D.O.); (C.R.S.)
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Extracellular Signals Induce Glycoprotein M6a Clustering of Lipid Rafts and Associated Signaling Molecules. J Neurosci 2017; 37:4046-4064. [PMID: 28275160 DOI: 10.1523/jneurosci.3319-16.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/25/2017] [Accepted: 02/18/2017] [Indexed: 01/08/2023] Open
Abstract
Lipid raft domains, where sphingolipids and cholesterol are enriched, concentrate signaling molecules. To examine how signaling protein complexes are clustered in rafts, we focused on the functions of glycoprotein M6a (GPM6a), which is expressed at a high concentration in developing mouse neurons. Using imaging of lipid rafts, we found that GPM6a congregated in rafts in a GPM6a palmitoylation-dependent manner, thereby contributing to lipid raft clustering. In addition, we found that signaling proteins downstream of GPM6a, such as Rufy3, Rap2, and Tiam2/STEF, accumulated in lipid rafts in a GPM6a-dependent manner and were essential for laminin-dependent polarity during neurite formation in neuronal development. In utero RNAi targeting of GPM6a resulted in abnormally polarized neurons with multiple neurites. These results demonstrate that GPM6a induces the clustering of lipid rafts, which supports the raft aggregation of its associated downstream molecules for acceleration of neuronal polarity determination. Therefore, GPM6a acts as a signal transducer that responds to extracellular signals.SIGNIFICANCE STATEMENT Lipid raft domains, where sphingolipids and cholesterol are enriched, concentrate signaling molecules. We focused on glycoprotein M6a (GPM6a), which is expressed at a high concentration in developing neurons. Using imaging of lipid rafts, we found that GPM6a congregated in rafts in a palmitoylation-dependent manner, thereby contributing to lipid raft clustering. In addition, we found that signaling proteins downstream of GPM6a accumulated in lipid rafts in a GPM6a-dependent manner and were essential for laminin-dependent polarity during neurite formation. In utero RNAi targeting of GPM6a resulted in abnormally polarized neurons with multiple neurites. These results demonstrate that GPM6a induces the clustering of lipid rafts, which supports the raft aggregation of its associated downstream molecules for acceleration of polarity determination. Therefore, GPM6a acts as a signal transducer that responds to extracellular signals.
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Lee JY, Petratos S. Thyroid Hormone Signaling in Oligodendrocytes: from Extracellular Transport to Intracellular Signal. Mol Neurobiol 2016; 53:6568-6583. [PMID: 27427390 DOI: 10.1007/s12035-016-0013-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/10/2016] [Indexed: 01/24/2023]
Abstract
Thyroid hormone plays an important role in central nervous system (CNS) development, including the myelination of variable axonal calibers. It is well-established that thyroid hormone is required for the terminal differentiation of oligodendrocyte precursor cells (OPCs) into myelinating oligodendrocytes by inducing rapid cell-cycle arrest and constant transcription of pro-differentiation genes. This is well supported by the hypomyelinating phenotypes exhibited by patients with congenital hypothyroidism, cretinism. During development, myelinating oligodendrocytes only appear after the formation of neural circuits, indicating that the timing of oligodendrocyte differentiation is important. Since fetal and post-natal serum thyroid hormone levels peak at the stage of active myelination, it is suspected that the timing of oligodendrocyte development is finely controlled by thyroid hormone. The essential machinery for thyroid hormone signaling such as deiodinase activity (utilized by cells to auto-regulate the level of thyroid hormone), and nuclear thyroid hormone receptors (for gene transcription) are expressed on oligodendrocytes. In this review, we discuss the known and potential thyroid hormone signaling pathways that may regulate oligodendrocyte development and CNS myelination. Moreover, we evaluate the potential of targeting thyroid hormone signaling for white matter injury or disease.
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Affiliation(s)
- Jae Young Lee
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia.,ToolGen, Inc., #1204, Byucksan Digital Valley 6-cha, Seoul, South Korea
| | - Steven Petratos
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia.
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27
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Glu-tubulin is a marker for Schwann cells and can distinguish between schwannomas and neurofibromas. Histochem Cell Biol 2016; 146:467-77. [PMID: 27278446 DOI: 10.1007/s00418-016-1455-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
Schwann cells generate myelin sheaths around the axons of the peripheral nervous system, thus facilitating efficient nerve impulse propagation. Two main tumor types can arise from peripheral nerves, schwannomas and neurofibromas, which are sometimes difficult to distinguish and may require the use of diagnostic biomarkers. Here, we characterize a new marker for Schwann cells and its potential use as a diagnostic marker for schwannomas. Immunohistochemistry for Glu-tubulin, a posttranslational modification of α-tubulin, was performed in mouse and human tissues. This technique labels Schwann cells but not oligodendrocytes. All peripheral nerves were immunoreactive for this antibody, including large nerve trunks, thin myelinated nerves, as well as the myenteric and submucous plexus of the digestive tract. In the mouse brain, many neurons were immunoreactive for Glu-tubulin but oligodendrocytes were negative. During embryo development, immunoreactive nerves were already found at E10. In Schwann cells, the staining is restricted to the myelin sheaths and is not present in the perinuclear cytoplasm or the Ranvier nodes. Primary cultures of fibroblasts and Schwann cells were established from mouse sciatic nerves, and Western blot analysis showed that Glu-tubulin immunoreactivity was found in the Schwann cells but not in the fibroblasts. Clinical specimens of schwannomas (n = 20) and neurofibromas (n = 20) were stained with anti-Glu-tubulin antibodies. Schwannomas presented a strong staining in all tumor cells, whereas neurofibromas had a light speckled staining pattern, easily distinguishable from the one found in schwannomas. In conclusion, Glu-tubulin can be used as a marker of Schwann cells and can help in diagnosing peripheral nerve tumors.
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28
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Chang KJ, Redmond SA, Chan JR. Remodeling myelination: implications for mechanisms of neural plasticity. Nat Neurosci 2016; 19:190-7. [PMID: 26814588 DOI: 10.1038/nn.4200] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 10/12/2015] [Indexed: 02/08/2023]
Abstract
One of the most significant paradigm shifts in membrane remodeling is the emerging view that membrane transformation is not exclusively controlled by cytoskeletal rearrangement, but also by biophysical constraints, adhesive forces, membrane curvature and compaction. One of the most exquisite examples of membrane remodeling is myelination. The advent of myelin was instrumental in advancing the nervous system during vertebrate evolution. With more rapid and efficient communication between neurons, faster and more complex computations could be performed in a given time and space. Our knowledge of how myelin-forming oligodendrocytes select and wrap axons has been limited by insufficient spatial and temporal resolution. By virtue of recent technological advances, progress has clarified longstanding controversies in the field. Here we review insights into myelination, from target selection to axon wrapping and membrane compaction, and discuss how understanding these processes has unexpectedly opened new avenues of insight into myelination-centered mechanisms of neural plasticity.
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Affiliation(s)
- Kae-Jiun Chang
- Department of Neurology, University of California, San Francisco, California, USA
| | - Stephanie A Redmond
- Department of Neurology, University of California, San Francisco, California, USA.,Program in Neuroscience, University of California, San Francisco, California, USA
| | - Jonah R Chan
- Department of Neurology, University of California, San Francisco, California, USA.,Program in Neuroscience, University of California, San Francisco, California, USA
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29
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Möbius W, Nave KA, Werner HB. Electron microscopy of myelin: Structure preservation by high-pressure freezing. Brain Res 2016; 1641:92-100. [PMID: 26920467 DOI: 10.1016/j.brainres.2016.02.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 02/16/2016] [Indexed: 10/24/2022]
Abstract
Electron microscopic visualization of nervous tissue morphology is crucial when aiming to understand the biogenesis and structure of myelin in healthy and pathological conditions. However, accurate interpretation of electron micrographs requires excellent tissue preservation. In this short review we discuss the recent utilization of tissue fixation by high-pressure freezing and freeze-substitution, which now supplements aldehyde fixation in the preparation of samples for electron microscopy of myelin. Cryofixation has proven well suited to yield both, improved contrast and excellent preservation of structural detail of the axon/myelin-unit in healthy and mutant mice and can also be applied to other model organisms, including aquatic species. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37075 Göttingen, Germany.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
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30
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Takeda K, Dezawa M, Kitada M. The expression of PLP/DM-20 mRNA is restricted to the oligodendrocyte-lineage cells in the adult rat spinal cord. Histochem Cell Biol 2015; 145:147-61. [PMID: 26563642 DOI: 10.1007/s00418-015-1384-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2015] [Indexed: 11/28/2022]
Abstract
Proteolipid protein (PLP) is the major component of myelin; its gene encodes two major splicing variants: PLP and DM-20. Compared with PLP, DM-20 lacks the amino acids encoded by exon IIIb. The expression of PLP/DM-20 in cells outside the oligodendrocyte-lineage is unclear. To address this issue, we analyzed the detailed expression pattern of PLP/DM-20 mRNA in the adult rat spinal cord by in situ hybridization (ISH) with a cRNA probe complementary to DM-20 mRNA, which has been used to detect both PLP and DM-20 both mRNA. ISH did not label the cells expressing NeuN nor glial fibrillary acidic protein but detected those expressing Olig2, indicating that PLP/DM-20 mRNA are expressed only in oligodendrocyte-lineage cells. This cell population was expected to contain NG2-expressing oligodendrocyte precursor cells (OPCs), because some exhibited the expression of glutathione S-transferase pi isoform in the nucleus. A recent publication showed that OPCs express PLP but not DM-20 mRNA. However, no OPCs were detected. We performed ISH with a cRNA probe that specifically recognizes PLP mRNA to successfully detect some OPCs. Additionally, OPCs were detected by ISH with a cRNA probe complementary to DM-20 mRNA that was digested via alkaline hydrolysis prior to ISH. These findings collectively demonstrate that PLP and DM-20 mRNA expression is restricted to oligodendrocyte-lineage cells, and imply that the undigested cRNA probe complementary to the full-length DM-20 mRNA sequence only recognizes DM-20 mRNA and not the PLP counterpart when applied to ISH without denaturation/digestion methods.
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Affiliation(s)
- Kazuya Takeda
- Department of Stem Cell Biology and Histology, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.,Faculty of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Mari Dezawa
- Department of Stem Cell Biology and Histology, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
| | - Masaaki Kitada
- Department of Stem Cell Biology and Histology, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
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31
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The scales and tales of myelination: using zebrafish and mouse to study myelinating glia. Brain Res 2015; 1641:79-91. [PMID: 26498880 DOI: 10.1016/j.brainres.2015.10.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/06/2023]
Abstract
Myelin, the lipid-rich sheath that insulates axons to facilitate rapid conduction of action potentials, is an evolutionary innovation of the jawed-vertebrate lineage. Research efforts aimed at understanding the molecular mechanisms governing myelination have primarily focused on rodent models; however, with the advent of the zebrafish model system in the late twentieth century, the use of this genetically tractable, yet simpler vertebrate for studying myelination has steadily increased. In this review, we compare myelinating glial cell biology during development and regeneration in zebrafish and mouse and enumerate the advantages and disadvantages of using each model to study myelination. This article is part of a Special Issue entitled SI: Myelin Evolution.
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32
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Patzig J, Kusch K, Fledrich R, Eichel MA, Lüders KA, Möbius W, Sereda MW, Nave KA, Martini R, Werner HB. Proteolipid protein modulates preservation of peripheral axons and premature death when myelin protein zero is lacking. Glia 2015; 64:155-74. [PMID: 26393339 DOI: 10.1002/glia.22922] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/04/2015] [Indexed: 12/23/2022]
Abstract
Protein zero (P0) is the major structural component of peripheral myelin. Lack of this adhesion protein from Schwann cells causes a severe dysmyelinating neuropathy with secondary axonal degeneration in humans with the neuropathy Dejerine-Sottas syndrome (DSS) and in the corresponding mouse model (P0(null)-mice). In the mammalian CNS, the tetraspan-membrane protein PLP is the major structural myelin constituent and required for the long-term preservation of myelinated axons, which fails in hereditary spastic paraplegia (SPG type-2) and the relevant mouse model (Plp(null)-mice). The Plp-gene is also expressed in Schwann cells but PLP is of very low abundance in normal peripheral myelin; its function has thus remained enigmatic. Here we show that the abundance of PLP but not of other tetraspan myelin proteins is strongly increased in compact peripheral myelin of P0(null)-mice. To determine the functional relevance of PLP expression in the absence of P0, we generated P0(null)*Plp(null)-double-mutant mice. Compared with either single-mutant, P0(null)*Plp(null)-mice display impaired nerve conduction, reduced motor functions, and premature death. At the morphological level, axonal segments were frequently non-myelinated but in a one-to-one relationship with a hypertrophic Schwann cell. Importantly, axonal numbers were reduced in the vital phrenic nerve of P0(null)*Plp(null)-mice. In the absence of P0, thus, PLP also contributes to myelination by Schwann cells and to the preservation of peripheral axons. These data provide a link between the Schwann cell-dependent support of peripheral axons and the oligodendrocyte-dependent support of central axons.
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Affiliation(s)
- Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maria A Eichel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Katja A Lüders
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Hospital, Würzburg, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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33
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Epplen DB, Prukop T, Nientiedt T, Albrecht P, Arlt FA, Stassart RM, Kassmann CM, Methner A, Nave KA, Werner HB, Sereda MW. Curcumin therapy in a Plp1 transgenic mouse model of Pelizaeus-Merzbacher disease. Ann Clin Transl Neurol 2015; 2:787-96. [PMID: 26339673 PMCID: PMC4554440 DOI: 10.1002/acn3.219] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 04/07/2015] [Accepted: 05/07/2015] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE Pelizaeus-Merzbacher disease (PMD) is a progressive and lethal leukodystrophy caused by mutations affecting the proteolipid protein (PLP1) gene. The most common cause of PMD is a duplication of PLP1 and at present there is no curative therapy available. METHODS By using transgenic mice carrying additional copies of Plp1, we investigated whether curcumin diet ameliorates PMD symptoms. The diet of Plp1 transgenic mice was supplemented with curcumin for 10 consecutive weeks followed by phenotypical, histological and immunohistochemical analyses of the central nervous system. Plp1 transgenic and wild-type mice fed with normal chow served as controls. RESULTS Curcumin improved the motor phenotype performance of Plp1 transgenic mice by 50% toward wild-type level and preserved myelinated axons by 35% when compared to Plp1 transgenic controls. Furthermore, curcumin reduced astrocytosis, microgliosis and lymphocyte infiltration in Plp1 transgenic mice. Curcumin diet did not affect the pathologically increased Plp1 mRNA abundance. However, high glutathione levels indicating an oxidative misbalance in the white matter of Plp1 transgenic mice were restored by curcumin treatment. INTERPRETATION Curcumin may potentially serve as an antioxidant therapy of PMD caused by PLP1 gene duplication.
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Affiliation(s)
- Dirk B Epplen
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
| | - Thomas Prukop
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany ; Institute of Clinical Pharmacology, University Medical Center Göttingen (UMG) Göttingen, Germany
| | - Tobias Nientiedt
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
| | - Philipp Albrecht
- Department of Neurology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Germany
| | - Friederike A Arlt
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
| | - Ruth M Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany ; Institute of Neuropathology, University Medical Center Göttingen (UMG) Göttingen, Germany
| | - Celia M Kassmann
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
| | - Axel Methner
- Focus Program Translational Neuroscience (FTN), Rhine Main Neuroscience Network (rmn2), Department of Neurology, Johannes Gutenberg University Medical Center Mainz Mainz, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany
| | - Michael W Sereda
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine Göttingen, Germany ; Department of Clinical Neurophysiology, University Medical Center Göttingen (UMG) Göttingen, Germany
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34
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Abstract
Myelination of axons in the nervous system of vertebrates enables fast, saltatory impulse propagation, one of the best-understood concepts in neurophysiology. However, it took a long while to recognize the mechanistic complexity both of myelination by oligodendrocytes and Schwann cells and of their cellular interactions. In this review, we highlight recent advances in our understanding of myelin biogenesis, its lifelong plasticity, and the reciprocal interactions of myelinating glia with the axons they ensheath. In the central nervous system, myelination is also stimulated by axonal activity and astrocytes, whereas myelin clearance involves microglia/macrophages. Once myelinated, the long-term integrity of axons depends on glial supply of metabolites and neurotrophic factors. The relevance of this axoglial symbiosis is illustrated in normal brain aging and human myelin diseases, which can be studied in corresponding mouse models. Thus, myelinating cells serve a key role in preserving the connectivity and functions of a healthy nervous system.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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35
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Denninger AR, Demé B, Cristiglio V, LeDuc G, Feller WB, Kirschner DA. Neutron scattering from myelin revisited: bilayer asymmetry and water-exchange kinetics. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:3198-211. [PMID: 25478838 PMCID: PMC4257619 DOI: 10.1107/s1399004714023815] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/28/2014] [Indexed: 11/18/2022]
Abstract
Rapid nerve conduction in the central and peripheral nervous systems (CNS and PNS, respectively) of higher vertebrates is brought about by the ensheathment of axons with myelin, a lipid-rich, multilamellar assembly of membranes. The ability of myelin to electrically insulate depends on the regular stacking of these plasma membranes and on the presence of a number of specialized membrane-protein assemblies in the sheath, including the radial component, Schmidt-Lanterman incisures and the axo-glial junctions of the paranodal loops. The disruption of this fine-structure is the basis for many demyelinating neuropathies in the CNS and PNS. Understanding the processes that govern myelin biogenesis, maintenance and destabilization requires knowledge of myelin structure; however, the tight packing of internodal myelin and the complexity of its junctional specializations make myelin a challenging target for comprehensive structural analysis. This paper describes an examination of myelin from the CNS and PNS using neutron diffraction. This investigation revealed the dimensions of the bilayers and aqueous spaces of myelin, asymmetry between the cytoplasmic and extracellular leaflets of the membrane, and the distribution of water and exchangeable hydrogen in internodal multilamellar myelin. It also uncovered differences between CNS and PNS myelin in their water-exchange kinetics.
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Affiliation(s)
| | - Bruno Demé
- Institut Laue–Langevin (ILL), CS 20156, F-38042 Grenoble CEDEX 9, France
| | - Viviana Cristiglio
- Institut Laue–Langevin (ILL), CS 20156, F-38042 Grenoble CEDEX 9, France
| | - Géraldine LeDuc
- European Synchrotron Radiation Facility (ESRF), CS 40220, F-38043 Grenoble CEDEX 9, France
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36
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Igarashi M. Proteomic identification of the molecular basis of mammalian CNS growth cones. Neurosci Res 2014; 88:1-15. [PMID: 25066522 DOI: 10.1016/j.neures.2014.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/13/2014] [Accepted: 07/02/2014] [Indexed: 11/28/2022]
Abstract
The growth cone, which is a unique structure with high motility that forms at the tips of extending axons and dendrites, is crucial to neuronal network formation. Axonal growth of the mammalian CNS is most likely achieved by the complicated coordination of cytoskeletal rearrangement and vesicular trafficking via many proteins. Before recent advances, no methods to identify numerous proteins existed; however, proteomics revolutionarily resolved such problems. In this review, I summarize the profiles of the mammalian growth cone proteins revealed by proteomics as the molecular basis of the growth cone functions, with molecular mapping. These results should be used as a basis for understanding the mechanisms of the complex mammalian CNS developmental process.
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Affiliation(s)
- Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan; Trans-disciplinary Program, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan.
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37
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Mita S, de Monasterio-Schrader P, Fünfschilling U, Kawasaki T, Mizuno H, Iwasato T, Nave KA, Werner HB, Hirata T. Transcallosal Projections Require Glycoprotein M6-Dependent Neurite Growth and Guidance. Cereb Cortex 2014; 25:4111-25. [PMID: 24917275 DOI: 10.1093/cercor/bhu129] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The function of mature neurons critically relies on the developmental outgrowth and projection of their cellular processes. It has long been postulated that the neuronal glycoproteins M6a and M6b are involved in axon growth because these four-transmembrane domain-proteins of the proteolipid protein family are highly enriched on growth cones, but in vivo evidence has been lacking. Here, we report that the function of M6 proteins is required for normal axonal extension and guidance in vivo. In mice lacking both M6a and M6b, a severe hypoplasia of axon tracts was manifested. Most strikingly, the corpus callosum was reduced in thickness despite normal densities of cortical projection neurons. In single neuron tracing, many axons appeared shorter and disorganized in the double-mutant cortex, and some of them were even misdirected laterally toward the subcortex. Probst bundles were not observed. Upon culturing, double-mutant cortical and cerebellar neurons displayed impaired neurite outgrowth, indicating a cell-intrinsic function of M6 proteins. A rescue experiment showed that the intracellular loop of M6a is essential for the support of neurite extension. We propose that M6 proteins are required for proper extension and guidance of callosal axons that follow one of the most complex trajectories in the mammalian nervous system.
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Affiliation(s)
- Sakura Mita
- Division of Brain Function, National Institute of Genetics, Graduate University for Advanced Studies (Sokendai), Mishima 411-8540, Japan
| | | | - Ursula Fünfschilling
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Goettingen, Germany
| | - Takahiko Kawasaki
- Division of Brain Function, National Institute of Genetics, Graduate University for Advanced Studies (Sokendai), Mishima 411-8540, Japan
| | - Hidenobu Mizuno
- Division of Neurogenetics, National Institute of Genetics, Graduate University for Advanced Studies (Sokendai), Mishima 411-8540, Japan
| | - Takuji Iwasato
- Division of Neurogenetics, National Institute of Genetics, Graduate University for Advanced Studies (Sokendai), Mishima 411-8540, Japan
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Goettingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Goettingen, Germany
| | - Tatsumi Hirata
- Division of Brain Function, National Institute of Genetics, Graduate University for Advanced Studies (Sokendai), Mishima 411-8540, Japan
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38
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Dere E, Winkler D, Ritter C, Ronnenberg A, Poggi G, Patzig J, Gernert M, Müller C, Nave KA, Ehrenreich H, Werner HB. Gpm6b deficiency impairs sensorimotor gating and modulates the behavioral response to a 5-HT2A/C receptor agonist. Behav Brain Res 2014; 277:254-63. [PMID: 24768641 DOI: 10.1016/j.bbr.2014.04.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 11/29/2022]
Abstract
The neuronal tetraspan proteins, M6A (Gpm6a) and M6B (Gpm6b), belong to the family of proteolipids that are widely expressed in the brain. We recently reported Gpm6a deficiency as a monogenetic cause of claustrophobia in mice. Its homolog proteolipid, Gpm6b, is ubiquitously expressed in neurons and oligodendrocytes. Gpm6b is involved in neuronal differentiation and myelination. It interacts with the N-terminal domain of the serotonin transporter (SERT) and decreases cell-surface expression of SERT. In the present study, we employed Gpm6b null mutant mice (Gpm6b(-/-)) to search for behavioral functions of Gpm6b. We studied male and female Gpm6b(-/-) mice and their wild-type (WT, Gpm6b(+/+)) littermates in an extensive behavioral test battery. Additionally, we investigated whether Gpm6b(-/-) mice exhibit changes in the behavioral response to a 5-HT2A/C receptor agonist. We found that Gpm6b(-/-) mice display completely normal sensory and motor functions, cognition, as well as social and emotionality-like (anxiety, depression) behaviors. On top of this inconspicuous behavioral profile, Gpm6b(-/-) mice of both genders exhibit a selective impairment in prepulse inhibition of the acoustic startle response. Furthermore, in contrast to WT mice that show the typical locomotion suppression and increase in grooming activity after intraperitoneal administration of DOI [(±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride], Gpm6b(-/-) mice demonstrate a blunted behavioral response to this 5-HT2A/C receptor agonist. To conclude, Gpm6b deficiency impairs sensorimotor gating and modulates the behavioral response to a serotonergic challenge.
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Affiliation(s)
- Ekrem Dere
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Daniela Winkler
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Caroline Ritter
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Anja Ronnenberg
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Giulia Poggi
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Manuela Gernert
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine, Hannover, Germany
| | - Christian Müller
- Department of Psychiatry & Psychotherapy, University of Erlangen, Germany
| | - Klaus-Armin Nave
- DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Göttingen, Germany; Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hannelore Ehrenreich
- Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Panfoli I, Bruschi M, Santucci L, Calzia D, Ravera S, Petretto A, Candiano G. Myelin proteomics: the past, the unexpected and the future. Expert Rev Proteomics 2014; 11:345-54. [PMID: 24702188 DOI: 10.1586/14789450.2014.900444] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Myelin proteomics has been the subject of intense research over the last decade, and its profiling has achieved good results by both in-gel and mass spectrometry-based techniques. 1280 proteins have been identified, a number expected to increase. Some of the identified proteins are as yet not established as true components of myelin. There appears to be a limit in our ability to discover markers of myelin biogenesis, function and disease. Myelin can be easily isolated free of contaminants, thanks to its lipidic nature, which however necessitates pretreatment with detergents before mass spectrometry analysis. Here, the key issue of solubilization of myelin proteins for mass spectrometry measurements is addressed. An in-depth characterization of the myelin proteome would have a profound impact on our knowledge of its pathology and physiology. Future quantitative proteomic studies of the low-abundance myelin protein complement, likely representing key regulatory components, may in future provide molecular description of the dysmyelinating/demyelinating diseases.
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Affiliation(s)
- Isabella Panfoli
- Department of Pharmacy, University of Genoa, Viale Bendetto XV, 5, 16132 Genova, Italy
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Bakhti M, Aggarwal S, Simons M. Myelin architecture: zippering membranes tightly together. Cell Mol Life Sci 2014; 71:1265-77. [PMID: 24165921 PMCID: PMC11113231 DOI: 10.1007/s00018-013-1492-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 09/11/2013] [Accepted: 10/07/2013] [Indexed: 12/12/2022]
Abstract
Rapid nerve conduction requires the coating of axons by a tightly packed multilayered myelin membrane. In the central nervous system, myelin is formed from cellular processes that extend from oligodendrocytes and wrap in a spiral fashion around an axon, resulting in the close apposition of adjacent myelin membrane bilayers. In this review, we discuss the physical principles underlying the zippering of the plasma membrane of oligodendrocytes at the cytoplasmic and extracellular leaflet. We propose that the interaction of the myelin basic protein with the cytoplasmic leaflet of the myelin bilayer triggers its polymerization into a fibrous network that drives membrane zippering and protein extrusion. In contrast, the adhesion of the extracellular surfaces of myelin requires the down-regulation of repulsive components of the glycocalyx, in order to uncover weak and unspecific attractive forces that bring the extracellular surfaces into close contact. Unveiling the mechanisms of myelin membrane assembly at the cytoplasmic and extracelluar sites may help to understand how the myelin bilayers are disrupted and destabilized in the different demyelinating diseases.
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Affiliation(s)
- Mostafa Bakhti
- Max-Planck-Institute of Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, Germany
- Department of Neurology, University of Göttingen, Robert-Koch-Str. 40, Göttingen, Germany
- Present Address: Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
| | - Shweta Aggarwal
- Max-Planck-Institute of Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, Germany
- Department of Neurology, University of Göttingen, Robert-Koch-Str. 40, Göttingen, Germany
| | - Mikael Simons
- Max-Planck-Institute of Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, Germany
- Department of Neurology, University of Göttingen, Robert-Koch-Str. 40, Göttingen, Germany
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Patzig J, Dworschak MS, Martens AK, Werner HB. Septins in the glial cells of the nervous system. Biol Chem 2014; 395:143-9. [DOI: 10.1515/hsz-2013-0240] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 09/13/2013] [Indexed: 01/19/2023]
Abstract
Abstract
The capacity of cytoskeletal septins to mediate diverse cellular processes is related to their ability to assemble as distinct heterooligomers and higher order structures. However, in many cell types the functional relevance of septins is not well understood. This minireview provides a brief overview of our current knowledge about septins in the non-neuronal cells of the vertebrate nervous system, collectively termed ‘glial cells’, i.e., astrocytes, microglia, oligodendrocytes, and Schwann cells. The dysregulation of septins observed in various models of myelin pathology is discussed with respect to implications for hereditary neuralgic amyotrophy (HNA) caused by mutations of the human SEPT9-gene.
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42
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Dagley LF, White CA, Liao Y, Shi W, Smyth GK, Orian JM, Emili A, Purcell AW. Quantitative proteomic profiling reveals novel region-specific markers in the adult mouse brain. Proteomics 2014; 14:241-61. [PMID: 24259518 DOI: 10.1002/pmic.201300196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 11/07/2013] [Accepted: 11/11/2013] [Indexed: 11/06/2022]
Abstract
Despite major advances in neuroscience, a comprehensive understanding of the structural and functional components of the adult brain compartments remains to be fully elucidated at a quantitative molecular level. Indeed, over half of the soluble- and membrane-annotated proteins are currently unmapped within online digital brain atlases. In this study, two complementary approaches were used to assess the unique repertoire of proteins enriched within select regions of the adult mouse CNS, including the brain stem, cerebellum, and remaining brain hemispheres. Of the 1200 proteins visualized by 2D-DIGE, approximately 150 (including cytosolic and membrane proteins) were found to exhibit statistically significant changes in relative abundance thus representing putative region-specific brain markers. In addition to using a high-precision (18) O-labeling strategy for the quantitative LC-MS/MS mapping of membrane proteins isolated from myelin-enriched fractions, we have identified over 1000 proteins that have yet to be described in any other mammalian myelin proteome. A comparison of our myelin proteome was made to an existing transcriptome database containing mRNA abundance profiles during oligodendrocyte differentiation and has confirmed statistically significant abundance changes for ∼500 of these newly mapped proteins, thus revealing new roles in oligodendrocyte and myelin biology. These data offer a resource for the neuroscience community studying the molecular basis for specialized neuronal activities in the CNS and myelin-related disorders. The MS proteomics data associated with this manuscript have been deposited to the ProteomeXchange Consortium with the dataset identifier PXD000327 (http://proteomecentral.proteomexchange.org/dataset/PXD000327).
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Affiliation(s)
- Laura F Dagley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia; Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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43
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Werner HB. Do we have to reconsider the evolutionary emergence of myelin? Front Cell Neurosci 2013; 7:217. [PMID: 24298238 PMCID: PMC3828561 DOI: 10.3389/fncel.2013.00217] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/29/2013] [Indexed: 02/02/2023] Open
Affiliation(s)
- Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine Göttingen, Germany
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de Monasterio-Schrader P, Patzig J, Möbius W, Barrette B, Wagner TL, Kusch K, Edgar JM, Brophy PJ, Werner HB. Uncoupling of neuroinflammation from axonal degeneration in mice lacking the myelin protein tetraspanin-2. Glia 2013; 61:1832-47. [DOI: 10.1002/glia.22561] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 12/11/2022]
Affiliation(s)
| | - Julia Patzig
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Wiebke Möbius
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
| | - Benoit Barrette
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Tadzio L. Wagner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Kathrin Kusch
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Julia M. Edgar
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow; Bearsden Road, Glasgow G61 1QH United Kingdom
| | - Peter J. Brophy
- Centre for Neuroregeneration; University of Edinburgh; United Kingdom
| | - Hauke B. Werner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
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45
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Nawaz S, Schweitzer J, Jahn O, Werner HB. Molecular evolution of myelin basic protein, an abundant structural myelin component. Glia 2013; 61:1364-77. [DOI: 10.1002/glia.22520] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Schanila Nawaz
- Max Planck Institute of Experimental Medicine; Göttingen; Germany
| | - Jörn Schweitzer
- Developmental Biology; Institute of Biology 1; University of Freiburg; Germany
| | - Olaf Jahn
- Max Planck Institute of Experimental Medicine; Göttingen; Germany
| | - Hauke B. Werner
- Max Planck Institute of Experimental Medicine; Göttingen; Germany
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46
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El-Kordi A, Kästner A, Grube S, Klugmann M, Begemann M, Sperling S, Hammerschmidt K, Hammer C, Stepniak B, Patzig J, de Monasterio-Schrader P, Strenzke N, Flügge G, Werner HB, Pawlak R, Nave KA, Ehrenreich H. A single gene defect causing claustrophobia. Transl Psychiatry 2013; 3:e254. [PMID: 23632458 PMCID: PMC3641414 DOI: 10.1038/tp.2013.28] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Claustrophobia, the well-known fear of being trapped in narrow/closed spaces, is often considered a conditioned response to traumatic experience. Surprisingly, we found that mutations affecting a single gene, encoding a stress-regulated neuronal protein, can cause claustrophobia. Gpm6a-deficient mice develop normally and lack obvious behavioral abnormalities. However, when mildly stressed by single-housing, these mice develop a striking claustrophobia-like phenotype, which is not inducible in wild-type controls, even by severe stress. The human GPM6A gene is located on chromosome 4q32-q34, a region linked to panic disorder. Sequence analysis of 115 claustrophobic and non-claustrophobic subjects identified nine variants in the noncoding region of the gene that are more frequent in affected individuals (P=0.028). One variant in the 3'untranslated region was linked to claustrophobia in two small pedigrees. This mutant mRNA is functional but cannot be silenced by neuronal miR124 derived itself from a stress-regulated transcript. We suggest that loosing dynamic regulation of neuronal GPM6A expression poses a genetic risk for claustrophobia.
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Affiliation(s)
- A El-Kordi
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany
| | - A Kästner
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - S Grube
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - M Klugmann
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - M Begemann
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany
| | - S Sperling
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - K Hammerschmidt
- Cognitive Ethology Laboratory, German Primate Center, Göttingen, Germany
| | - C Hammer
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - B Stepniak
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - J Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | | | - N Strenzke
- Department of Otolaryngology, Georg-August-University, Göttingen, Germany
| | - G Flügge
- DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany,Department of Clinical Neurobiology, German Primate Center, Göttingen, Germany
| | - H B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - R Pawlak
- Laboratory of Neuronal Plasticity and Behaviour, University of Exeter Medical School, University of Exeter, Exeter, UK
| | - K-A Nave
- DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany,Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany,Max Planck Institute of Experimental Medicine, Hermann-Rein Street 3, 37075 Göttingen, Germany. E-mail: (HE) or (K-AN)
| | - H Ehrenreich
- Division of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany,Max Planck Institute of Experimental Medicine, Hermann-Rein Street 3, 37075 Göttingen, Germany. E-mail: (HE) or (K-AN)
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47
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Loss of electrostatic cell-surface repulsion mediates myelin membrane adhesion and compaction in the central nervous system. Proc Natl Acad Sci U S A 2013; 110:3143-8. [PMID: 23382229 DOI: 10.1073/pnas.1220104110] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
During the development of the central nervous system (CNS), oligodendrocytes wrap their plasma membrane around axons to form a multilayered stack of tightly attached membranes. Although intracellular myelin compaction and the role of myelin basic protein has been investigated, the forces that mediate the close interaction of myelin membranes at their external surfaces are poorly understood. Such extensive bilayer-bilayer interactions are usually prevented by repulsive forces generated by the glycocalyx, a dense and confluent layer of large and negatively charged oligosaccharides. Here we investigate the molecular mechanisms underlying myelin adhesion and compaction in the CNS. We revisit the role of the proteolipid protein and analyze the contribution of oligosaccharides using cellular assays, biophysical tools, and transgenic mice. We observe that differentiation of oligodendrocytes is accompanied by a striking down-regulation of components of their glycocalyx. Both in vitro and in vivo experiments indicate that the adhesive properties of the proteolipid protein, along with the reduction of sialic acid residues from the cell surface, orchestrate myelin membrane adhesion and compaction in the CNS. We suggest that loss of electrostatic cell-surface repulsion uncovers weak and unspecific attractive forces in the bilayer that bring the extracellular surfaces of a membrane into close contact over long distances.
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48
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Werner HB, Krämer-Albers EM, Strenzke N, Saher G, Tenzer S, Ohno-Iwashita Y, De Monasterio-Schrader P, Möbius W, Moser T, Griffiths IR, Nave KA. A critical role for the cholesterol-associated proteolipids PLP and M6B in myelination of the central nervous system. Glia 2013; 61:567-86. [PMID: 23322581 DOI: 10.1002/glia.22456] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 11/30/2012] [Indexed: 12/13/2022]
Abstract
The formation of central nervous system myelin by oligodendrocytes requires sterol synthesis and is associated with a significant enrichment of cholesterol in the myelin membrane. However, it is unknown how oligodendrocytes concentrate cholesterol above the level found in nonmyelin membranes. Here, we demonstrate a critical role for proteolipids in cholesterol accumulation. Mice lacking the most abundant myelin protein, proteolipid protein (PLP), are fully myelinated, but PLP-deficient myelin exhibits a reduced cholesterol content. We therefore hypothesized that "high cholesterol" is not essential in the myelin sheath itself but is required for an earlier step of myelin biogenesis that is fully compensated for in the absence of PLP. We also found that a PLP-homolog, glycoprotein M6B, is a myelin component of low abundance. By targeting the Gpm6b-gene and crossbreeding, we found that single-mutant mice lacking either PLP or M6B are fully myelinated, while double mutants remain severely hypomyelinated, with enhanced neurodegeneration and premature death. As both PLP and M6B bind membrane cholesterol and associate with the same cholesterol-rich oligodendroglial membrane microdomains, we suggest a model in which proteolipids facilitate myelination by sequestering cholesterol. While either proteolipid can maintain a threshold level of cholesterol in the secretory pathway that allows myelin biogenesis, lack of both proteolipids results in a severe molecular imbalance of prospective myelin membrane. However, M6B is not efficiently sorted into mature myelin, in which it is 200-fold less abundant than PLP. Thus, only PLP contributes to the high cholesterol content of myelin by association and co-transport.
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Affiliation(s)
- Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany.
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49
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Kammula EC, Mötter J, Gorgels A, Jonas E, Hoffmann S, Willbold D. Brain transcriptome-wide screen for HIV-1 Nef protein interaction partners reveals various membrane-associated proteins. PLoS One 2012; 7:e51578. [PMID: 23284715 PMCID: PMC3524239 DOI: 10.1371/journal.pone.0051578] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/02/2012] [Indexed: 01/23/2023] Open
Abstract
HIV-1 Nef protein contributes essentially to the pathology of AIDS by a variety of protein-protein-interactions within the host cell. The versatile functionality of Nef is partially attributed to different conformational states and posttranslational modifications, such as myristoylation. Up to now, many interaction partners of Nef have been identified using classical yeast two-hybrid screens. Such screens rely on transcriptional activation of reporter genes in the nucleus to detect interactions. Thus, the identification of Nef interaction partners that are integral membrane proteins, membrane-associated proteins or other proteins that do not translocate into the nucleus is hampered. In the present study, a split-ubiquitin based yeast two-hybrid screen was used to identify novel membrane-localized interaction partners of Nef. More than 80% of the hereby identified interaction partners of Nef are transmembrane proteins. The identified hits are GPM6B, GPM6A, BAP31, TSPAN7, CYB5B, CD320/TCblR, VSIG4, PMEPA1, OCIAD1, ITGB1, CHN1, PH4, CLDN10, HSPA9, APR-3, PEBP1 and B3GNT, which are involved in diverse cellular processes like signaling, apoptosis, neurogenesis, cell adhesion and protein trafficking or quality control. For a subfraction of the hereby identified proteins we present data supporting their direct interaction with HIV-1 Nef. We discuss the results with respect to many phenotypes observed in HIV infected cells and patients. The identified Nef interaction partners may help to further elucidate the molecular basis of HIV-related diseases.
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Affiliation(s)
- Ellen C. Kammula
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Physical Biology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Jessica Mötter
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Physical Biology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Alexandra Gorgels
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Esther Jonas
- Institute of Physical Biology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Silke Hoffmann
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
| | - Dieter Willbold
- Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Physical Biology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail:
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50
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Live imaging of targeted cell ablation in Xenopus: a new model to study demyelination and repair. J Neurosci 2012; 32:12885-95. [PMID: 22973012 DOI: 10.1523/jneurosci.2252-12.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Live imaging studies of the processes of demyelination and remyelination have so far been technically limited in mammals. We have thus generated a Xenopus laevis transgenic line allowing live imaging and conditional ablation of myelinating oligodendrocytes throughout the CNS. In these transgenic pMBP-eGFP-NTR tadpoles the myelin basic protein (MBP) regulatory sequences, specific to mature oligodendrocytes, are used to drive expression of an eGFP (enhanced green fluorescent protein) reporter fused to the Escherichia coli nitroreductase (NTR) selection enzyme. This enzyme converts the innocuous prodrug metronidazole (MTZ) to a cytotoxin. Using two-photon imaging in vivo, we show that pMBP-eGFP-NTR tadpoles display a graded oligodendrocyte ablation in response to MTZ, which depends on the exposure time to MTZ. MTZ-induced cell death was restricted to oligodendrocytes, without detectable axonal damage. After cessation of MTZ treatment, remyelination proceeded spontaneously, but was strongly accelerated by retinoic acid. Altogether, these features establish the Xenopus pMBP-eGFP-NTR line as a novel in vivo model for the study of demyelination/remyelination processes and for large-scale screens of therapeutic agents promoting myelin repair.
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