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Taki S, Boron WF, Moss FJ. Novel RPTPγ and RPTPζ splice variants from mixed neuron-astrocyte hippocampal cultures as well as from the hippocampi of newborn and adult mice. Front Physiol 2024; 15:1406448. [PMID: 38952869 PMCID: PMC11215419 DOI: 10.3389/fphys.2024.1406448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/06/2024] [Indexed: 07/03/2024] Open
Abstract
Receptor protein tyrosine phosphatases γ and ζ (RPTPγ and RPTPζ) are transmembrane signaling proteins with extracellular carbonic anhydrase-like domains that play vital roles in the development and functioning of the central nervous system (CNS) and are implicated in tumor suppression, neurodegeneration, and sensing of extracellular [CO2] and [HCO3 -]. RPTPγ expresses throughout the body, whereas RPTPζ preferentially expresses in the CNS. Here, we investigate differential RPTPγ-RPTPζ expression in three sources derived from a wild-type laboratory strain of C57BL/6 mice: (a) mixed neuron-astrocyte hippocampal (HC) cultures 14 days post isolation from P0-P2 pups; (b) P0-P2 pup hippocampi; and (c) 9- to 12-week-old adult hippocampi. Regarding RPTPγ, we detect the Ptprg variant-1 (V1) transcript, representing canonical exons 1-30. Moreover, we newly validate the hypothetical assembly [XM_006517956] (propose name, Ptprg-V3), which lacks exon 14. Both transcripts are in all three HC sources. Regarding RPTPζ, we confirm the expression of Ptprz1-V1, detecting it in pups and adults but not in cultures, and Ptprz1-V3 through Ptprz1-V7 in all three preparations. We newly validate hypothetical assemblies Ptprz1-X1 (in cultures and pups), Ptprz1-X2 (in all three), and Ptprz1-X5 (in pups and adults) and propose to re-designate them as Ptprz1-V0, Ptprz1-V2, and Ptprz1-V8, respectively. The diversity of RPTPγ and RPTPζ splice variants likely corresponds to distinct signaling functions, in different cellular compartments, during development vs later life. In contrast to previous studies that report divergent RPTPγ and RPTPζ protein expressions in neurons and sometimes in the glia, we observe that RPTPγ and RPTPζ co-express in the somata and processes of almost all HC neurons but not in astrocytes, in all three HC preparations.
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Affiliation(s)
- Sara Taki
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Walter F. Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Fraser J. Moss
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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2
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Kalafatakis I, Savvaki M, Velona T, Karagogeos D. Implication of Contactins in Demyelinating Pathologies. Life (Basel) 2021; 11:life11010051. [PMID: 33451101 PMCID: PMC7828632 DOI: 10.3390/life11010051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/09/2021] [Accepted: 01/11/2021] [Indexed: 12/19/2022] Open
Abstract
Demyelinating pathologies comprise of a variety of conditions where either central or peripheral myelin is attacked, resulting in white matter lesions and neurodegeneration. Myelinated axons are organized into molecularly distinct domains, and this segregation is crucial for their proper function. These defined domains are differentially affected at the different stages of demyelination as well as at the lesion and perilesion sites. Among the main players in myelinated axon organization are proteins of the contactin (CNTN) group of the immunoglobulin superfamily (IgSF) of cell adhesion molecules, namely Contactin-1 and Contactin-2 (CNTN1, CNTN2). The two contactins perform their functions through intermolecular interactions, which are crucial for myelinated axon integrity and functionality. In this review, we focus on the implication of these two molecules as well as their interactors in demyelinating pathologies in humans. At first, we describe the organization and function of myelinated axons in the central (CNS) and the peripheral (PNS) nervous system, further analyzing the role of CNTN1 and CNTN2 as well as their interactors in myelination. In the last section, studies showing the correlation of the two contactins with demyelinating pathologies are reviewed, highlighting the importance of these recognition molecules in shaping the function of the nervous system in multiple ways.
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3
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Fernández-Calle R, Galán-Llario M, Gramage E, Zapatería B, Vicente-Rodríguez M, Zapico JM, de Pascual-Teresa B, Ramos A, Ramos-Álvarez MP, Uribarri M, Ferrer-Alcón M, Herradón G. Role of RPTPβ/ζ in neuroinflammation and microglia-neuron communication. Sci Rep 2020; 10:20259. [PMID: 33219280 PMCID: PMC7679445 DOI: 10.1038/s41598-020-76415-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Pleiotrophin (PTN) is a cytokine that is upregulated in different neuroinflammatory disorders. Using mice with transgenic PTN overexpression in the brain (Ptn-Tg), we have found a positive correlation between iNos and Tnfα mRNA and Ptn mRNA levels in the prefrontal cortex (PFC) of LPS-treated mice. PTN is an inhibitor of Receptor Protein Tyrosine Phosphatase (RPTP) β/ζ, which is mainly expressed in the central nervous system. We aimed to test if RPTPβ/ζ is involved in the modulation of neuroinflammatory responses using specific inhibitors of RPTPβ/ζ (MY10 and MY33-3). Treatment with MY10 potentiated LPS-induced microglial responses in the mouse PFC. Surprisingly, MY10 caused a decrease in LPS-induced NF-κB p65 expression, suggesting that RPTPβ/ζ may be involved in a novel mechanism of potentiation of microglial activation independent of the NF-κB p65 pathway. MY33-3 and MY10 limited LPS-induced nitrites production and iNos increases in BV2 microglial cells. SH-SY5Y neuronal cells were treated with the conditioned media from MY10/LPS-treated BV2 cells. Conditioned media from non-stimulated and from LPS-stimulated BV2 cells increased the viability of SH-SY5Y cultures. RPTPβ/ζ inhibition in microglial cells disrupted this neurotrophic effect of microglia, suggesting that RPTPβ/ζ plays a role in the neurotrophic phenotype of microglia and in microglia-neuron communication.
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Affiliation(s)
- Rosalía Fernández-Calle
- Departamento de Ciencias Farmacéuticas y de La Salud, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - Milagros Galán-Llario
- Departamento de Ciencias Farmacéuticas y de La Salud, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - Esther Gramage
- Departamento de Ciencias Farmacéuticas y de La Salud, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - Begoña Zapatería
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - Marta Vicente-Rodríguez
- Departamento de Ciencias Farmacéuticas y de La Salud, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - José M Zapico
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - Beatriz de Pascual-Teresa
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - Ana Ramos
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - M Pilar Ramos-Álvarez
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain
| | - María Uribarri
- BRAINco Biopharma, S.L., Bizkaia Technology Park, Derio, Spain
| | | | - Gonzalo Herradón
- Departamento de Ciencias Farmacéuticas y de La Salud, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28925, Alcorcón, Madrid, Spain.
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4
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Dubessy AL, Mazuir E, Rappeneau Q, Ou S, Abi Ghanem C, Piquand K, Aigrot MS, Thétiot M, Desmazières A, Chan E, Fitzgibbon M, Fleming M, Krauss R, Zalc B, Ranscht B, Lubetzki C, Sol-Foulon N. Role of a Contactin multi-molecular complex secreted by oligodendrocytes in nodal protein clustering in the CNS. Glia 2019; 67:2248-2263. [PMID: 31328333 PMCID: PMC6851800 DOI: 10.1002/glia.23681] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 01/06/2023]
Abstract
The fast and reliable propagation of action potentials along myelinated fibers relies on the clustering of voltage‐gated sodium channels at nodes of Ranvier. Axo‐glial communication is required for assembly of nodal proteins in the central nervous system, yet the underlying mechanisms remain poorly understood. Oligodendrocytes are known to support node of Ranvier assembly through paranodal junction formation. In addition, the formation of early nodal protein clusters (or prenodes) along axons prior to myelination has been reported, and can be induced by oligodendrocyte conditioned medium (OCM). Our recent work on cultured hippocampal neurons showed that OCM‐induced prenodes are associated with an increased conduction velocity (Freeman et al., 2015). We here unravel the nature of the oligodendroglial secreted factors. Mass spectrometry analysis of OCM identified several candidate proteins (i.e., Contactin‐1, ChL1, NrCAM, Noelin2, RPTP/Phosphacan, and Tenascin‐R). We show that Contactin‐1 combined with RPTP/Phosphacan or Tenascin‐R induces clusters of nodal proteins along hippocampal GABAergic axons. Furthermore, Contactin‐1‐immunodepleted OCM or OCM from Cntn1‐null mice display significantly reduced clustering activity, that is restored by addition of soluble Contactin‐1. Altogether, our results identify Contactin‐1 secreted by oligodendrocytes as a novel factor that may influence early steps of nodal sodium channel cluster formation along specific axon populations.
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Affiliation(s)
- Anne-Laure Dubessy
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France.,Assistance Publique-Hôpitaux de Paris, GH Pitié-Salpêtrière, Paris, France
| | - Elisa Mazuir
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Quentin Rappeneau
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Sokounthie Ou
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Charly Abi Ghanem
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Kevin Piquand
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Marie-Stéphane Aigrot
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Melina Thétiot
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Anne Desmazières
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Eric Chan
- Vertex Pharmaceuticals Incorporated, Boston, Massachusetts
| | | | - Mark Fleming
- Vertex Pharmaceuticals Incorporated, Boston, Massachusetts
| | - Raul Krauss
- Disarm Therapeutics, Cambridge, Massachusetts
| | - Bernard Zalc
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Barbara Ranscht
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Catherine Lubetzki
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France.,Assistance Publique-Hôpitaux de Paris, GH Pitié-Salpêtrière, Paris, France
| | - Nathalie Sol-Foulon
- Sorbonne Université, Inserm, CNRS, UMR7225, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
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5
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Tanga N, Kuboyama K, Kishimoto A, Kihara M, Kiyonari H, Watanabe T, Fujikawa A, Noda M. Behavioral and neurological analyses of adult mice carrying null and distinct loss-of-receptor function mutations in protein tyrosine phosphatase receptor type Z (PTPRZ). PLoS One 2019; 14:e0217880. [PMID: 31194769 PMCID: PMC6563982 DOI: 10.1371/journal.pone.0217880] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/20/2019] [Indexed: 12/13/2022] Open
Abstract
Protein tyrosine phosphatase receptor type Z (PTPRZ) is preferentially expressed in the central nervous system as two transmembrane receptor isoforms PTPRZ-A/B and one secretory isoform PTPRZ-S. Ptprz-knockout mice lacking the expression of all three isoforms show behavioral, learning, and neurological abnormalities, including increased exploratory activities to novelty, deficits in spatial and contextual learning, and reduced responses to methamphetamine, relative to wild-type mice. To investigate whether PTPRZ isoforms play distinct physiological roles, we herein performed behavioral studies on two knock-in mouse lines: One expresses the catalytically inactive Cys-1930 to Ser (CS) mutants of PTPRZ-A/B, while the other generated in the present study expresses catalytically active mutants of PTPRZ-A/B lacking the negative regulatory PTP-D2 domain and C-terminal PDZ-binding motif (ΔD2) instead of wild-type PTPRZ-A/-B. In contrast to Ptprz-knockout mice, neither increased responses to novelty in the open field nor memory impairments in the inhibitory-avoidance task were observed in Ptprz-CS or Ptprz-ΔD2 mice. However, the effects of methamphetamine on locomotor activity were significantly weaker in Ptprz-KO mice and CS mutant mice than in wild-type mice, but were normal in ΔD2 mutant mice. Furthermore, microdialysis experiments revealed that methamphetamine-evoked dopamine release in the nucleus accumbens was reduced in Ptprz-KO mice and CS mutant mice. These results suggest that the extracellular region of PTPRZ, including the secretory isoform, is crucial for behavioral responses to novelty and the formation of aversive memories, whereas the PTPase activities of PTPRZ receptor isoforms are involved in regulating the dopaminergic system.
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Affiliation(s)
- Naomi Tanga
- Division of Molecular Neurobiology, National Institute for Basic Biology (NIBB), Higashiyama, Myodaiji-cho, Okazaki, Aichi, Japan
- School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Higashiyama, Myodaiji-cho, Okazaki, Aichi, Japan
| | - Kazuya Kuboyama
- Division of Molecular Neurobiology, National Institute for Basic Biology (NIBB), Higashiyama, Myodaiji-cho, Okazaki, Aichi, Japan
| | - Ayako Kishimoto
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women’s University, Kita-uoya-nishi-machi, Nara, Japan
| | - Miho Kihara
- Laboratories Laboratory for Animal Resource Development, RIKEN Center for Biosystems Dynamics Research, Minatojima Minami-machi, Chuou-ku, Kobe, Japan
| | - Hiroshi Kiyonari
- Laboratories Laboratory for Animal Resource Development, RIKEN Center for Biosystems Dynamics Research, Minatojima Minami-machi, Chuou-ku, Kobe, Japan
- Laboratory for Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Minatojima Minami-machi, Chuou-ku, Kobe, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women’s University, Kita-uoya-nishi-machi, Nara, Japan
| | - Akihiro Fujikawa
- Division of Molecular Neurobiology, National Institute for Basic Biology (NIBB), Higashiyama, Myodaiji-cho, Okazaki, Aichi, Japan
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology (NIBB), Higashiyama, Myodaiji-cho, Okazaki, Aichi, Japan
- School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Higashiyama, Myodaiji-cho, Okazaki, Aichi, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, 4529 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, Japan
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6
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Cui R, Lwigale P. Expression of the heparin-binding growth factors Midkine and pleiotrophin during ocular development. Gene Expr Patterns 2019; 32:28-37. [PMID: 30825522 DOI: 10.1016/j.gep.2019.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/18/2019] [Accepted: 02/21/2019] [Indexed: 12/17/2022]
Abstract
Midkine (MDK) and Pleiotrophin (PTN) belong to a group of heparin-binding growth factors that has been shown to have pleiotropic functions in various biological processes during development and disease. Development of the vertebrate eye is a multistep process that involves coordinated interactions between neuronal and non-neuronal cells, but very little is known about the potential function of MDK and PTN in these processes. In this study, we demonstrate by section in situ hybridization, the spatiotemporal expression of MDK and PTN during ocular development in chick and mouse. We show that MDK and PTN are expressed in dynamic patterns that overlap in a few non-neuronal tissues in the anterior eye and in neuronal cell layers of the posterior eye. We show that the expression patterns of MDK and PTN are only conserved in a few tissues in chick and mouse but they overlap with the expression of some of their receptors LRP1, RPTPZ, ALK, NOTCH2, ITGβ1, SDC1, and SDC3. The dynamic expression patterns of MDK, PTN and their receptors suggest that they function together during the multistep process of ocular development and they may play important roles in cell proliferation, adhesion, and migration of neuronal and non-neuronal cells.
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Affiliation(s)
- Ruda Cui
- Department of BioSciences, Rice University, Houston, TX, USA
| | - Peter Lwigale
- Department of BioSciences, Rice University, Houston, TX, USA.
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7
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Protein Phosphatases-A Touchy Enemy in the Battle Against Glioblastomas: A Review. Cancers (Basel) 2019; 11:cancers11020241. [PMID: 30791455 PMCID: PMC6406705 DOI: 10.3390/cancers11020241] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/15/2019] [Accepted: 02/16/2019] [Indexed: 12/19/2022] Open
Abstract
Glioblastoma (GBM) is the most common malignant tumor arising from brain parenchyma. Although many efforts have been made to develop therapies for GBM, the prognosis still remains poor, mainly because of the difficulty in total resection of the tumor mass from brain tissue and the resistance of the residual tumor against standard chemoradiotherapy. Therefore, novel adjuvant therapies are urgently needed. Recent genome-wide analyses of GBM cases have clarified molecular signaling mechanisms underlying GBM biology. However, results of clinical trials targeting phosphorylation-mediated signaling have been unsatisfactory to date. Protein phosphatases are enzymes that antagonize phosphorylation signaling by dephosphorylating phosphorylated signaling molecules. Recently, the critical roles of phosphatases in the regulation of oncogenic signaling in malignant tumor cells have been reported, and tumorigenic roles of deregulated phosphatases have been demonstrated in GBM. However, a detailed mechanism underlying phosphatase-mediated signaling transduction in the regulation of GBM has not been elucidated, and such information is necessary to apply phosphatases as a therapeutic target for GBM. This review highlights and summarizes the phosphatases that have crucial roles in the regulation of oncogenic signaling in GBM cells.
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8
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Chatterjee M, Schild D, Teunissen CE. Contactins in the central nervous system: role in health and disease. Neural Regen Res 2019; 14:206-216. [PMID: 30530999 PMCID: PMC6301169 DOI: 10.4103/1673-5374.244776] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/17/2018] [Indexed: 01/06/2023] Open
Abstract
Contactins are a group of cell adhesion molecules that are mainly expressed in the brain and play pivotal roles in the organization of axonal domains, axonal guidance, neuritogenesis, neuronal development, synapse formation and plasticity, axo-glia interactions and neural regeneration. Contactins comprise a family of six members. Their absence leads to malformed axons and impaired nerve conduction. Contactin mediated protein complex formation is critical for the organization of the axon in early central nervous system development. Mutations and differential expression of contactins have been identified in neuro-developmental or neurological disorders. Taken together, contactins are extensively studied in the context of nervous system development. This review summarizes the physiological roles of all six members of the Contactin family in neurodevelopment as well as their involvement in neurological/neurodevelopmental disorders.
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Affiliation(s)
- Madhurima Chatterjee
- Amsterdam UMC, VU University Medical Center, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Göttingen, Germany
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany
- DFG Excellence Cluster 171, University of Göttingen, Göttingen, Germany
| | - Charlotte E. Teunissen
- Amsterdam UMC, VU University Medical Center, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam, The Netherlands
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9
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Cijsouw T, Ramsey AM, Lam TT, Carbone BE, Blanpied TA, Biederer T. Mapping the Proteome of the Synaptic Cleft through Proximity Labeling Reveals New Cleft Proteins. Proteomes 2018; 6:proteomes6040048. [PMID: 30487426 PMCID: PMC6313906 DOI: 10.3390/proteomes6040048] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/15/2018] [Accepted: 11/18/2018] [Indexed: 12/21/2022] Open
Abstract
Synapses are specialized neuronal cell-cell contacts that underlie network communication in the mammalian brain. Across neuronal populations and circuits, a diverse set of synapses is utilized, and they differ in their molecular composition to enable heterogenous connectivity patterns and functions. In addition to pre- and post-synaptic specializations, the synaptic cleft is now understood to be an integral compartment of synapses that contributes to their structural and functional organization. Aiming to map the cleft proteome, this study applied a peroxidase-mediated proximity labeling approach and used the excitatory synaptic cell adhesion protein SynCAM 1 fused to horseradish peroxidase (HRP) as a reporter in cultured cortical neurons. This reporter marked excitatory synapses as measured by confocal microcopy and was targeted to the edge zone of the synaptic cleft as determined using 3D dSTORM super-resolution imaging. Proximity labeling with a membrane-impermeant biotin-phenol compound restricted labeling to the cell surface, and Label-Free Quantitation (LFQ) mass spectrometry combined with ratiometric HRP tagging of membrane vs. synaptic surface proteins was used to identify the proteomic content of excitatory clefts. Novel cleft candidates were identified, and Receptor-type tyrosine-protein phosphatase zeta was selected and successfully validated. This study supports the robust applicability of peroxidase-mediated proximity labeling for synaptic cleft proteomics and its potential for understanding synapse heterogeneity in health and changes in diseases such as psychiatric disorders and addiction.
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Affiliation(s)
- Tony Cijsouw
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Austin M Ramsey
- Department of Physiology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - TuKiet T Lam
- Yale/NIDA Neuroproteomics Center, New Haven, CT 06511, USA.
- W.M. Keck Biotechnology Resource Laboratory, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Beatrice E Carbone
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Thomas A Blanpied
- Department of Physiology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
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10
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Fujikawa A, Chow JPH, Matsumoto M, Suzuki R, Kuboyama K, Yamamoto N, Noda M. Identification of novel splicing variants of protein tyrosine phosphatase receptor type Z. J Biochem 2017; 162:381-390. [PMID: 28992190 DOI: 10.1093/jb/mvx042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 06/14/2017] [Indexed: 11/13/2022] Open
Abstract
Protein tyrosine phosphatase receptor type Z (PTPRZ, also known as PTPζ or RPTPβ) is preferentially expressed in the central nervous system (CNS). PTPRZ plays important roles during development and adulthood in CNS myelination, learning and memory. Three splicing isoforms for PTPRZ have been identified to date: two receptor type isoforms, PTPRZ-A and PTPRZ-B, and one secretory isoform, PTPRZ-S. We herein identified novel PTPRZ receptor sub-isoforms without a seven-amino acid sequence encoded by exon 16. This sequence forms a part of the helix-turn-helix segment called the 'wedge' structure, which is located at the N-terminal region in the membrane-proximal protein tyrosine phosphatase domain. In contrast to conventional receptor isoforms with uniform expression, the deleted isoforms were expressed in the brain, but not in the retina, indicating the tissue-specific splicing of exon 16. Biochemical analyses of PTPRZ intracellular regions revealed differences in the characteristics of the deleted form, namely, stronger binding activity to postsynaptic density protein 95 (PSD95) and greater enrichment in the postsynaptic density fraction than the full-length form. Furthermore, the exon 16-deleted form exhibited higher catalytic efficiency in vitro. These results suggest that sub-isoforms of PTPRZ have different functions because of variations in the wedge structure.
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Affiliation(s)
- Akihiro Fujikawa
- Division of Molecular Neurobiology, National Institute for Basic Biology
| | - Jeremy Pak Hong Chow
- Division of Molecular Neurobiology, National Institute for Basic Biology.,School of Life Science, Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Masahito Matsumoto
- Division of Molecular Neurobiology, National Institute for Basic Biology
| | - Ryoko Suzuki
- Division of Molecular Neurobiology, National Institute for Basic Biology
| | - Kazuya Kuboyama
- Division of Molecular Neurobiology, National Institute for Basic Biology
| | - Naoki Yamamoto
- Laboratory of Molecular Biology & Histochemistry, Fujita Health University, 1-98, Toyoake, Aichi 470-1192, Japan
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology.,School of Life Science, Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
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11
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Targeting PTPRZ inhibits stem cell-like properties and tumorigenicity in glioblastoma cells. Sci Rep 2017; 7:5609. [PMID: 28717188 PMCID: PMC5514153 DOI: 10.1038/s41598-017-05931-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 06/06/2017] [Indexed: 01/08/2023] Open
Abstract
The R5 subfamily of receptor-type protein tyrosine phosphatases (RPTPs) comprises PTPRZ and PTPRG. A recent study on primary human glioblastomas suggested a close association between PTPRZ1 (human PTPRZ) expression and cancer stemness. However, the functional roles of PTPRZ activity in glioma stem cells have remained unclear. In the present study, we found that sphere-forming cells from the rat C6 and human U251 glioblastoma cell lines showed high expression levels of PTPRZ-B, the short receptor isoform of PTPRZ. Stable PTPRZ knockdown altered the expression levels of stem cell transcription factors such as SOX2, OLIG2, and POU3F2 and decreased the sphere-forming abilities of these cells. Suppressive effects on the cancer stem-like properties of the cells were also observed following the knockdown of PTPRG. Here, we identified NAZ2329, a cell-permeable small molecule that allosterically inhibits both PTPRZ and PTPRG. NAZ2329 reduced the expression of SOX2 in C6 and U251 cells and abrogated the sphere-forming abilities of these cells. Tumor growth in the C6 xenograft mouse model was significantly slower with the co-treatment of NAZ2329 with temozolomide, an alkylating agent, than with the individual treatments. These results indicate that pharmacological inhibition of R5 RPTPs is a promising strategy for the treatment of malignant gliomas.
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Karus M, Ulc A, Ehrlich M, Czopka T, Hennen E, Fischer J, Mizhorova M, Qamar N, Brüstle O, Faissner A. Regulation of oligodendrocyte precursor maintenance by chondroitin sulphate glycosaminoglycans. Glia 2015; 64:270-86. [PMID: 26454153 DOI: 10.1002/glia.22928] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 09/16/2015] [Indexed: 01/06/2023]
Abstract
Chondroitin sulfate proteoglycans (CSPGs) have been proven to inhibit morphological maturation of oligodendrocytes as well as their myelination capabilities. Yet, it remained unclear, whether CSPGs and/or their respective chondroitin sulfate glycosaminoglycan (CS-GAG) side chains also regulate the oligodendrocyte lineage progression. Here, we initially show that CS-GAGs detected by the monoclonal antibody 473HD are expressed by primary rat NG2-positive oligodendrocyte precursor cells (OPCs) and O4-positive immature oligodendrocytes. CS-GAGs become down-regulated with ongoing oligodendrocyte differentiation. Enzymatic removal of the CS-GAG chains by the bacterial enzyme Chondroitinase ABC (ChABC) promoted spontaneous differentiation of proliferating rat OPCs toward O4-positive immature oligodendrocytes. Upon forced differentiation, the enzymatic removal of the CS-GAGs accelerated oligodendrocyte differentiation toward both MBP-positive and membrane forming oligodendrocytes. These processes were attenuated on enriched CSPG fractions, mainly consisting of Phosphacan/RPTPβ/ζ and to less extent of Brevican and NG2. To qualify CS-GAGs as universal regulators of oligodendrocyte biology, we finally tested the effect of CS-GAG removal on OPCs from different sources such as mouse cortical oligospheres, mouse spinal cord neurospheres, and most importantly human-induced pluripotent stem cell-derived radial glia-like neural precursor cells. For all culture systems used, we observed a similar inhibitory effect of CS-GAGs on oligodendrocyte differentiation. In conclusion, this study clearly suggests an important fundamental principle for complex CS-GAGs to regulate the oligodendrocyte lineage progression. Moreover, the use of ChABC in order to promote oligodendrocyte differentiation toward myelin gene expressing cells might be an applicable therapeutic option to enhance white matter repair.
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Affiliation(s)
- Michael Karus
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr-University Bochum, Bochum, Germany.,Institute of Reconstructive Neurobiology, LIFE&BRAIN Center, Bonn, Germany
| | - Annika Ulc
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Marc Ehrlich
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Tim Czopka
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Eva Hennen
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Julia Fischer
- Institute of Reconstructive Neurobiology, LIFE&BRAIN Center, Bonn, Germany
| | - Marija Mizhorova
- Institute of Reconstructive Neurobiology, LIFE&BRAIN Center, Bonn, Germany
| | - Naila Qamar
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, LIFE&BRAIN Center, Bonn, Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University Bochum, Bochum, Germany
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13
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Dwyer CA, Katoh T, Tiemeyer M, Matthews RT. Neurons and glia modify receptor protein-tyrosine phosphatase ζ (RPTPζ)/phosphacan with cell-specific O-mannosyl glycans in the developing brain. J Biol Chem 2015; 290:10256-73. [PMID: 25737452 DOI: 10.1074/jbc.m114.614099] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Indexed: 01/06/2023] Open
Abstract
Protein O-mannosylation is a glycan modification that is required for normal nervous system development and function. Mutations in genes involved in protein O-mannosyl glycosylation give rise to a group of neurodevelopmental disorders known as congenital muscular dystrophies (CMDs) with associated CNS abnormalities. Our previous work demonstrated that receptor protein-tyrosine phosphatase ζ (RPTPζ)/phosphacan is hypoglycosylated in a mouse model of one of these CMDs, known as muscle-eye-brain disease, a disorder that is caused by loss of an enzyme (protein O-mannose β-1,2-N-acetylglucosaminyltransferase 1) that modifies O-mannosyl glycans. In addition, monoclonal antibodies Cat-315 and 3F8 were demonstrated to detect O-mannosyl glycan modifications on RPTPζ/phosphacan. Here, we show that O-mannosyl glycan epitopes recognized by these antibodies define biochemically distinct glycoforms of RPTPζ/phosphacan and that these glycoforms differentially decorate the surface of distinct populations of neural cells. To provide a further structural basis for immunochemically based glycoform differences, we characterized the O-linked glycan heterogeneity of RPTPζ/phosphacan in the early postnatal mouse brain by multidimensional mass spectrometry. Structural characterization of the O-linked glycans released from purified RPTPζ/phosphacan demonstrated that this protein is a significant substrate for protein O-mannosylation and led to the identification of several novel O-mannose-linked glycan structures, including sulfo-N-acetyllactosamine containing modifications. Taken together, our results suggest that specific glycan modifications may tailor the function of this protein to the unique needs of specific cells. Furthermore, their absence in CMDs suggests that hypoglycosylation of RPTPζ/phosphacan may have different functional consequences in neurons and glia.
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Affiliation(s)
- Chrissa A Dwyer
- From the Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York 13210 and
| | - Toshihiko Katoh
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Michael Tiemeyer
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Russell T Matthews
- From the Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York 13210 and
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14
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Lorenzetto E, Moratti E, Vezzalini M, Harroch S, Sorio C, Buffelli M. Distribution of different isoforms of receptor protein tyrosine phosphatase γ (Ptprg-RPTP γ) in adult mouse brain: upregulation during neuroinflammation. Brain Struct Funct 2013; 219:875-90. [DOI: 10.1007/s00429-013-0541-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 03/12/2013] [Indexed: 01/06/2023]
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15
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Protein tyrosine phosphatase receptor type z negatively regulates oligodendrocyte differentiation and myelination. PLoS One 2012; 7:e48797. [PMID: 23144976 PMCID: PMC3492236 DOI: 10.1371/journal.pone.0048797] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 10/01/2012] [Indexed: 01/06/2023] Open
Abstract
Background Fyn tyrosine kinase-mediated down-regulation of Rho activity through activation of p190RhoGAP is crucial for oligodendrocyte differentiation and myelination. Therefore, the loss of function of its counterpart protein tyrosine phosphatase (PTP) may enhance myelination during development and remyelination in demyelinating diseases. To test this hypothesis, we investigated whether Ptprz, a receptor-like PTP (RPTP) expressed abuntantly in oligodendrocyte lineage cells, is involved in this process, because we recently revealed that p190RhoGAP is a physiological substrate for Ptprz. Methodology/Principal Findings We found an early onset of the expression of myelin basic protein (MBP), a major protein of the myelin sheath, and early initiation of myelination in vivo during development of the Ptprz-deficient mouse, as compared with the wild-type. In addition, oligodendrocytes appeared earlier in primary cultures from Ptprz-deficient mice than wild-type mice. Furthermore, adult Ptprz-deficient mice were less susceptible to experimental autoimmune encephalomyelitis (EAE) induced by active immunization with myelin/oligodendrocyte glycoprotein (MOG) peptide than were wild-type mice. After EAE was induced, the tyrosine phosphorylation of p190RhoGAP increased significantly, and the EAE-induced loss of MBP was markedly suppressed in the white matter of the spinal cord in Ptprz-deficient mice. Here, the number of T-cells and macrophages/microglia infiltrating into the spinal cord did not differ between the two genotypes after MOG immunization. All these findings strongly support the validity of our hypothesis. Conclusions/Significance Ptprz plays a negative role in oligodendrocyte differentiation in early central nervous system (CNS) development and remyelination in demyelinating CNS diseases, through the dephosphorylation of substrates such as p190RhoGAP.
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16
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Zhang W, Savelieva KV, Tran DT, Pogorelov VM, Cullinan EB, Baker KB, Platt KA, Hu S, Rajan I, Xu N, Lanthorn TH. Characterization of PTPRG in knockdown and phosphatase-inactive mutant mice and substrate trapping analysis of PTPRG in mammalian cells. PLoS One 2012; 7:e45500. [PMID: 23029056 PMCID: PMC3447766 DOI: 10.1371/journal.pone.0045500] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/17/2012] [Indexed: 01/06/2023] Open
Abstract
Receptor tyrosine phosphatase gamma (PTPRG, or RPTPγ) is a mammalian receptor-like tyrosine phosphatase which is highly expressed in the nervous system as well as other tissues. Its function and biochemical characteristics remain largely unknown. We created a knockdown (KD) line of this gene in mouse by retroviral insertion that led to 98–99% reduction of RPTPγ gene expression. The knockdown mice displayed antidepressive-like behaviors in the tail-suspension test, confirming observations by Lamprianou et al. 2006. We investigated this phenotype in detail using multiple behavioral assays. To see if the antidepressive-like phenotype was due to the loss of phosphatase activity, we made a knock-in (KI) mouse in which a mutant, RPTPγ C1060S, replaced the wild type. We showed that human wild type RPTPγ protein, expressed and purified, demonstrated tyrosine phosphatase activity, and that the RPTPγ C1060S mutant was completely inactive. Phenotypic analysis showed that the KI mice also displayed some antidepressive-like phenotype. These results lead to a hypothesis that an RPTPγ inhibitor could be a potential treatment for human depressive disorders. In an effort to identify a natural substrate of RPTPγ for use in an assay for identifying inhibitors, “substrate trapping” mutants (C1060S, or D1028A) were studied in binding assays. Expressed in HEK293 cells, these mutant RPTPγs retained a phosphorylated tyrosine residue, whereas similarly expressed wild type RPTPγ did not. This suggested that wild type RPTPγ might auto-dephosphorylate which was confirmed by an in vitro dephosphorylation experiment. Using truncation and mutagenesis studies, we mapped the auto-dephosphorylation to the Y1307 residue in the D2 domain. This novel discovery provides a potential natural substrate peptide for drug screening assays, and also reveals a potential functional regulatory site for RPTPγ. Additional investigation of RPTPγ activity and regulation may lead to a better understanding of the biochemical underpinnings of human depression.
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Affiliation(s)
- Wandong Zhang
- Neuroscience Research, Lexicon Pharmaceuticals, Inc., The Woodlands, TX, USA.
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17
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Dwyer CA, Baker E, Hu H, Matthews RT. RPTPζ/phosphacan is abnormally glycosylated in a model of muscle-eye-brain disease lacking functional POMGnT1. Neuroscience 2012; 220:47-61. [PMID: 22728091 DOI: 10.1016/j.neuroscience.2012.06.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/09/2012] [Accepted: 06/11/2012] [Indexed: 01/06/2023]
Abstract
Congenital muscular dystrophies (CMDs) with associated brain abnormalities are a group of disorders characterized by muscular dystrophy and brain and eye abnormalities that are frequently caused by mutations in known or putative glycotransferases involved in protein O-mannosyl glycosylation. Previous work identified α-dystroglycan as the major substrate for O-mannosylation and its altered glycosylation the major cause of these disorders. However, work from several labs indicated that other proteins in the brain are also O-mannosylated and therefore could contribute to CMD pathology in patients with mutations in the protein O-mannosylation pathway, however few of these proteins have been identified and fully characterized in CMDs. In this study we identify receptor protein tyrosine phosphatase ζ (RPTPζ) and its secreted variant, phosphacan, as another potentially important substrate for protein O-mannosylation in the brain. Using a mouse model of muscle-eye-brain disease lacking functional protein O-mannose β-1,2-N-acetylglucosaminyltransferase (POMGnT1), we show that RPTPζ/phosphacan is shifted to a lower molecular weight and distinct carbohydrate epitopes normally detected on the protein are either absent or substantially reduced, including Human Natural Killer-1 (HNK-1) reactivity. The spatial and temporal expression patterns of these O-mannosylated forms of RPTPζ/phosphacan and its hypoglycosylation and loss of HNK-1 glycan epitopes in POMGnT1 knockouts are suggestive of a role in the neural phenotypes observed in patients and animal models of CMDs.
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Affiliation(s)
- C A Dwyer
- The Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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18
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A complex between contactin-1 and the protein tyrosine phosphatase PTPRZ controls the development of oligodendrocyte precursor cells. Proc Natl Acad Sci U S A 2011; 108:17498-503. [PMID: 21969550 DOI: 10.1073/pnas.1108774108] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The six members of the contactin (CNTN) family of neural cell adhesion molecules are involved in the formation and maintenance of the central nervous system (CNS) and have been linked to mental retardation and neuropsychiatric disorders such as autism. Five of the six CNTNs bind to the homologous receptor protein tyrosine phosphatases gamma (PTPRG) and zeta (PTPRZ), but the biological roles of these interactions remain unclear. We report here the cocrystal structure of the carbonic anhydrase-like domain of PTPRZ bound to tandem Ig repeats of CNTN1 and combine these structural data with binding assays to show that PTPRZ binds specifically to CNTN1 expressed at the surface of oligodendrocyte precursor cells. Furthermore, analyses of glial cell populations in wild-type and PTPRZ-deficient mice show that the binding of PTPRZ to CNTN1 expressed at the surface of oligodendrocyte precursor cells inhibits their proliferation and promotes their development into mature oligodendrocytes. Overall, these results implicate the PTPRZ/CNTN1 complex as a previously unknown modulator of oligodendrogenesis.
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19
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Navis AC, van den Eijnden M, Schepens JTG, Hooft van Huijsduijnen R, Wesseling P, Hendriks WJAJ. Protein tyrosine phosphatases in glioma biology. Acta Neuropathol 2010; 119:157-75. [PMID: 19936768 PMCID: PMC2808538 DOI: 10.1007/s00401-009-0614-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 11/13/2009] [Accepted: 11/13/2009] [Indexed: 01/01/2023]
Abstract
Gliomas are a diverse group of brain tumors of glial origin. Most are characterized by diffuse infiltrative growth in the surrounding brain. In combination with their refractive nature to chemotherapy this makes it almost impossible to cure patients using combinations of conventional therapeutic strategies. The drastically increased knowledge about the molecular underpinnings of gliomas during the last decade has elicited high expectations for a more rational and effective therapy for these tumors. Most studies on the molecular pathways involved in glioma biology thus far had a strong focus on growth factor receptor protein tyrosine kinase (PTK) and phosphatidylinositol phosphatase signaling pathways. Except for the tumor suppressor PTEN, much less attention has been paid to the PTK counterparts, the protein tyrosine phosphatase (PTP) superfamily, in gliomas. PTPs are instrumental in the reversible phosphorylation of tyrosine residues and have emerged as important regulators of signaling pathways that are linked to various developmental and disease-related processes. Here, we provide an overview of the current knowledge on PTP involvement in gliomagenesis. So far, the data point to the potential implication of receptor-type (RPTPδ, DEP1, RPTPμ, RPTPζ) and intracellular (PTP1B, TCPTP, SHP2, PTPN13) classical PTPs, dual-specific PTPs (MKP-1, VHP, PRL-3, KAP, PTEN) and the CDC25B and CDC25C PTPs in glioma biology. Like PTKs, these PTPs may represent promising targets for the development of novel diagnostic and therapeutic strategies in the treatment of high-grade gliomas.
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Affiliation(s)
- Anna C. Navis
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
- Department of Pathology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Monique van den Eijnden
- Department of Neurobiology, Geneva Research Center, Merck Serono International S.A, Geneva, Switzerland
| | - Jan T. G. Schepens
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | | | - Pieter Wesseling
- Department of Pathology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Wiljan J. A. J. Hendriks
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
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20
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Besser M, Horvat-Bröcker A, Eysel UT, Faissner A. Differential expression of receptor protein tyrosine phosphatases accompanies the reorganisation of the retina upon laser lesion. Exp Brain Res 2009; 198:37-47. [PMID: 19639307 DOI: 10.1007/s00221-009-1932-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Accepted: 06/29/2009] [Indexed: 12/14/2022]
Abstract
The regulation of protein phosphorylation plays an essential role in virtually all aspects of eukaryotic development. Beginning with the regulation of the cell cycle to cellular proliferation and differentiation, the delicate balance between the phosphorylating activity of kinases and the dephosphorylation by phosphatases controls the outcome of many signal transduction cascades. The generation of cellular diversity occurs in an environment that is structured by the extracellular matrix (ECM) which forms a surrounding niche for stem and progenitor cells. Cell-cell and cell-matrix interactions elicit specific signaling pathways that control cellular behavior. In pathological situations such as neural degenerating diseases, gene expression patterns and finally the composition of the ECM change dramatically. This leads to changes of cell behavior and finally results in the failure of regeneration and functional restoration in the adult central nervous system. In order to study the roles of tyrosine phosphatases and ECM in this context, we analyzed the effects of laser-induced retinal injury on the regulation of the receptor protein tyrosine phosphatases (RPTP) RPTPBr7, Phogrin and RPTPbeta/zeta. The latter occurs in several isoforms, including the soluble released chondroitin sulfate proteoglycan phosphacan that is expressed in the developing retina. The receptor variants RPTPbeta/zeta(long) and RPTPbeta/zeta(short) may serve as receptors of tenascin-proteins and serve as modulators of cell intrinsic signaling in response to the ECM. Using quantitative real-time RT-PCR analysis, we show here a time-dependent pattern of gene expression of these molecules following laser lesions of the retina.
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Affiliation(s)
- Manuela Besser
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
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21
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Chow JPH, Fujikawa A, Shimizu H, Suzuki R, Noda M. Metalloproteinase- and gamma-secretase-mediated cleavage of protein-tyrosine phosphatase receptor type Z. J Biol Chem 2008; 283:30879-89. [PMID: 18713734 PMCID: PMC2662165 DOI: 10.1074/jbc.m802976200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 08/12/2008] [Indexed: 11/06/2022] Open
Abstract
Protein-tyrosine phosphatase receptor type Z (Ptprz) is preferentially expressed in the brain as a major chondroitin sulfate proteoglycan. Three splicing variants, two receptor isoforms and one secretory isoform, are known. Here, we show that the extracellular region of the receptor isoforms of Ptprz are cleaved by metalloproteinases, and subsequently the membrane-tethered fragment is cleaved by presenilin/gamma-secretase, releasing its intracellular region into the cytoplasm; of note, the intracellular fragment of Ptprz shows nuclear localization. Administration of GM6001, an inhibitor of metalloproteinases, to mice demonstrated the metalloproteinase-mediated cleavage of Ptprz under physiological conditions. Furthermore, we identified the cleavage sites in the extracellular juxtamembrane region of Ptprz by tumor necrosis factor-alpha converting enzyme and matrix metalloproteinase 9. This is the first evidence of the metalloproteinase-mediated processing of a receptor-like protein-tyrosine phosphatase in the central nervous system.
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Affiliation(s)
- Jeremy Pak Hong Chow
- National Institute for Basic Biology and School of Life Science, The Graduate University for Advanced Studies, Okazaki, Aichi 444-8787, Japan
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22
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Abbott KL, Matthews RT, Pierce M. Receptor tyrosine phosphatase beta (RPTPbeta) activity and signaling are attenuated by glycosylation and subsequent cell surface galectin-1 binding. J Biol Chem 2008; 283:33026-35. [PMID: 18838383 DOI: 10.1074/jbc.m803646200] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
O-Mannosyl-linked glycosylation is abundant within the central nervous system, yet very few glycoproteins with this glycan modification have been identified. Congenital diseases with significant neurological defects arise from inactivating mutations found within the glycosyltransferases that act early in the O-mannosyl glycosylation pathway. The N-acetylglucosaminyltransferase known as GnT-Vb or -IX is highly expressed in brain and branches O-mannosyl-linked glycans. Our results using SH-SY5Y neuroblastoma cells indicate that GnT-Vb activity promotes the addition of the O-mannosyl-linked HNK-1 modification found on the developmentally regulated and neuron-specific receptor protein-tyrosine phosphatase beta (RPTPbeta). These changes in glycosylation accompany decreased cell-cell adhesion and increased rates of migration on laminin. In addition, we show that expression of GnT-Vb promotes its dimerization and inhibits RPTPbeta intrinsic phosphatase activity, resulting in higher levels of phosphorylated beta-catenin, suggesting a mechanism by which GnT-Vb glycosylation couples to changes in cell adhesion. GnT-Vb-mediated glycosylation of RPTPbeta promotes galectin-1 binding and RPTPbeta levels of retention on the cell surface. N-Acetyllactosamine, but not sucrose, treatment of cells results in decreased RPTP retention, showing that galectin-1 binding contributes to the increased retention after GnT-Vb expression. These results place GnT-Vb as a regulator of RPTPbeta signaling that influences cell-cell and cell-matrix interactions in the developing nervous system.
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Affiliation(s)
- Karen L Abbott
- Department of Biochemistry, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA.
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23
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Imamura O, Satoh Y, Endo S, Takishima K. Analysis of extracellular signal-regulated kinase 2 function in neural stem/progenitor cells via nervous system-specific gene disruption. Stem Cells 2008; 26:3247-56. [PMID: 18818436 DOI: 10.1634/stemcells.2008-0578] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Extracellular signal-regulated kinase 2 (ERK2) is involved in a variety of cell fate decisions during development, but its exact role in this process remains to be determined. To specifically focus on the role of ERK2 in the brain, and to avoid early lethalities, we used a conditional gene-targeting approach to preferentially inactivate Erk2 in the embryonic mouse brain. The resulting mutant mice were viable and were relatively normal in overall appearance. However, the loss of Erk2 resulted in a diminished proliferation of neural stem cells in the embryonic ventricular zone (VZ), although the survival and differentiation of these cells was unaffected. The multipotent neural progenitor cells (NPCs) isolated from ERK2-deficient brains also showed impaired proliferation, reduced self-renewal ability, and increased apoptosis. By neurosphere differentiation analysis we further observed that lineage-restricted glial progenitors were increased in ERK2-deficient mice. The decline in the self-renewal ability and multipotency of NPCs resulting from the loss of ERK2 was found to be caused at least in part by upregulation of the JAK-STAT signaling pathway and reduced G1/S cell cycle progression. Furthermore, by global expression analysis we found that neural stem cell markers, including Tenascin C NR2E1 (Tlx), and Lgals1 (Galectin-1), were significantly downregulated, whereas several glial lineage markers were upregulated in neurospheres derived from ERK2-deficient mice. Our results thus suggest that ERK2 is required both for the proliferation of neural stem cells in the VZ during embryonic development and in the maintenance of NPC multipotency by suppressing the commitment of these cells to a glial lineage.
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Affiliation(s)
- Osamu Imamura
- Department of Biochemistry, National Defense Medical College, Namiki, Tokorozawa, Japan
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24
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Plasmin-mediated processing of protein tyrosine phosphatase receptor type Z in the mouse brain. Neurosci Lett 2008; 442:208-12. [DOI: 10.1016/j.neulet.2008.07.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 06/24/2008] [Accepted: 07/11/2008] [Indexed: 01/06/2023]
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25
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Horvat-Bröcker A, Reinhard J, Illes S, Paech T, Zoidl G, Harroch S, Distler C, Knyazev P, Ullrich A, Faissner A. Receptor protein tyrosine phosphatases are expressed by cycling retinal progenitor cells and involved in neuronal development of mouse retina. Neuroscience 2008; 152:618-45. [PMID: 18308476 DOI: 10.1016/j.neuroscience.2008.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 12/14/2007] [Accepted: 01/10/2008] [Indexed: 11/21/2022]
Abstract
Receptor protein tyrosine phosphatases (RPTPs) appear to coordinate many aspects of neural development, including cell proliferation, migration and differentiation. Here we investigated potential roles of RPTPs in the developing mouse retina. Using a degenerate oligonucleotide-based reverse transcription polymerase chain reaction approach, we identified 11 different RPTPs in the retina at embryonic stage 13 (E13). Subsequently, the expression patterns of RPTPkappa, RPTPJ, RPTPRR, RPTPsigma, RPTPepsilon and RPTPgamma in the retina from embryonic stages to adult were analyzed in detail using quantitative real-time-PCR, in situ hybridization, immunohistochemistry and Western blotting. At E13, all six RPTPs are expressed in actively cycling retinal progenitor cells and postmitotic newborn retinal neurons. With ongoing maturation, RPTPkappa, RPTPJ, RPTPRR, RPTPsigma, RPTPepsilon and RPTPgamma display a different spatiotemporal regulation of mRNAs and proteins in the pre- and postnatal retina. Finally, in adulthood these six RPTPs localize to distinct cellular compartments of multiple retinal neurons. Additional studies in RPTPgamma(-/-) and RPTPbeta/zeta(-/-) (also known as PTPRZ1, RPTPbeta or RPTPzeta) mice at postnatal stage P1 reveal no apparent differences in retinal laminar organization or in the expression pattern of specific retinal cell-type markers when compared with wild type. However, in RPTPbeta/zeta(-/-) retinas, immunoreactivity of vimentin, a marker of Müller glial cells, is selectively reduced and the morphology of vimentin-immunoreactive radial processes of Müller cells is considerably disturbed. Our results suggest distinct roles of RPTPs in cell proliferation and establishing phenotypes of different retinal cells during retinogenesis as well as later in the maintenance of mature retina.
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Affiliation(s)
- A Horvat-Bröcker
- Department of Cell Morphology and molecular Neurobiology, Faculty of Biology, Ruhr-University-Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
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Faissner A, Heck N, Dobbertin A, Garwood J. DSD-1-Proteoglycan/Phosphacan and Receptor Protein Tyrosine Phosphatase-Beta Isoforms during Development and Regeneration of Neural Tissues. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 557:25-53. [PMID: 16955703 DOI: 10.1007/0-387-30128-3_3] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Interactions between neurons and glial cells play important roles in regulating key events of development and regeneration of the CNS. Thus, migrating neurons are partly guided by radial glia to their target, and glial scaffolds direct the growth and directional choice of advancing axons, e.g., at the midline. In the adult, reactive astrocytes and myelin components play a pivotal role in the inhibition of regeneration. The past years have shown that astrocytic functions are mediated on the molecular level by extracellular matrix components, which include various glycoproteins and proteoglycans. One important, developmentally regulated chondroitin sulfate proteoglycan is DSD-1-PG/phosphacan, a glial derived proteoglycan which represents a splice variant of the receptor protein tyrosine phosphatase (RPTP)-beta (also known as PTP-zeta). Current evidence suggests that this proteoglycan influences axon growth in development and regeneration, displaying inhibitory or stimulatory effects dependent on the mode of presentation, and the neuronal lineage. These effects seem to be mediated by neuronal receptors of the Ig-CAM superfamily.
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Affiliation(s)
- Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Ruhr-University, Bochum, Germany
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27
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Klausmeyer A, Garwood J, Faissner A. Differential expression of phosphacan/RPTPβ isoforms in the developing mouse visual system. J Comp Neurol 2007; 504:659-79. [PMID: 17722031 DOI: 10.1002/cne.21479] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The chondroitin sulfate proteoglycan DSD-1-PG/phosphacan represents one of four splice variants of receptor-protein-tyrosine-phosphatase-beta/zeta (RPTPbeta/zeta). This receptor is expressed by glial cells and occurs in two isoforms, RPTPbeta(long) and RPTPbeta(short). The secreted forms phosphacan and phosphacan short isoform (PSI) bind to extracellular matrix and adhesion molecules and might mediate astroglial effects on neuronal differentiation. Phosphacan and RPTPbeta(long) both carry the DSD-1 epitope, a glycosaminoglycan modification that is involved in stimulating neurite outgrowth of embryonic rat mesencephalic and hippocampal neurons in a polycationic environment. Additionally, phosphacan inhibits neurite outgrowth of embryonic DRG neurons in the presence of laminin. In the light of these functional properties we examined the expression patterns of the DSD-1 epitope and phosphacan isoforms in the developing mouse visual system. During retinal development the DSD-1 epitope appears around embryonic day (E)13, peaks around postnatal day (P)6, and is downregulated from P9 to adolescence. By comparison, the phosphacan core protein is first detectable at E12, reaches maximal levels around P14, and persists, although at lower levels, to adulthood. The DSD-1 epitope is restricted to the nerve fiber and the inner plexiform layers. In contrast, the phosphacan core protein immunoreactivity extends from the nerve fiber layer to the outer plexiform layer. The level of expression of the phosphacan/RPTPbeta gene was investigated by reverse-transcriptase polymerase chain reaction. These experiments suggest that there is a shift in the expression patterns of the different phosphacan/RPTPbeta isoforms during late embryonic and postnatal development. In situ hybridization experiments support the conclusion that at least one of the phosphacan/RPTPbeta isoforms in the retina is expressed by neurons.
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Affiliation(s)
- Alice Klausmeyer
- Department of Cellmorphology and Molecular Neurobiology, Ruhr-University-Bochum, 44801 Bochum, Germany
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28
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Dityatev A, Frischknecht R, Seidenbecher CI. Extracellular matrix and synaptic functions. Results Probl Cell Differ 2006; 43:69-97. [PMID: 17068968 DOI: 10.1007/400_025] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Comprehensive analysis of neuromuscular junction formation and recent data on synaptogenesis and long-term potentiation in the central nervous system revealed a number of extracellular matrix (ECM) molecules regulating different aspects of synaptic differentiation and function. The emerging mechanisms comprise interactions of ECM components with their cell surface receptors coupled to tyrosine kinase activities (agrin, integrin ligands, and reelin) and interactions with ion channels and transmitter receptors (Narp, tenascin-R and tenascin-C). These interactions may shape synaptic transmission and plasticity of excitatory synapses either via regulation of Ca2+ entry and postsynaptic expression of transmitter receptors or via control of GABAergic inhibition. The ECM molecules, derived from both neurons and glial cells and secreted into the extracellular space in an activity-dependent manner, may also shape synaptic plasticity through setting diffusion constraints for neurotransmitters, trophic factors and ions.
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Affiliation(s)
- Alexander Dityatev
- Institut für Neurophysiologie und Pathophysiologie, Universitätsklinikum Hamburg-Eppendorf, Germany.
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29
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von Holst A, Sirko S, Faissner A. The unique 473HD-Chondroitinsulfate epitope is expressed by radial glia and involved in neural precursor cell proliferation. J Neurosci 2006; 26:4082-94. [PMID: 16611825 PMCID: PMC6673890 DOI: 10.1523/jneurosci.0422-06.2006] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neural stem cells have been documented in both the developing and the mature adult CNSs of mammals. This cell population holds a considerable promise for therapeutical applications in a wide array of CNS diseases. Therefore, universally applicable strategies for the purification of this population to further its cell biological characterization are sought. Here, we report that the unique chondroitin sulfate epitope recognized by the monoclonal antibody 473HD is surface expressed on actively cycling, multipotent progenitor cells of the developing telencephalon with radial glia-like properties. When used for immunopanning, the antibody enriched at least threefold for neural stem/progenitor cells characterized by the ability to self-renew as neurospheres that generated all major neural lineages in differentiation assays. In contrast, the 473HD-depleted cell fraction was mostly devoid of neurosphere-forming cells. The isolation of 473HD-positive adult multipotent progenitors from the subependymal zone of the lateral ventricle wall revealed a substantial overlap with the known adult neural stem cell marker LewisX. When the chondroitin sulfates were removed from immunoselected 473HD-positive neural stem/progenitor cell surfaces by chondroitinase ABC treatment or perturbed by the monoclonal antibody 473HD that recognizes the unique DSD-1 chondroitin sulfate epitope, the generation of neurospheres was significantly reduced. Thus, the 473HD epitope could not only be used for the isolation of multipotent neural progenitors during forebrain development as well as from the adult neurogenic niche but may also constitute a functionally important entity of the neural stem cell niche.
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Sim FJ, Lang JK, Waldau B, Roy NS, Schwartz TE, Pilcher WH, Chandross KJ, Natesan S, Merrill JE, Goldman SA, Goldmanm SA. Complementary patterns of gene expression by human oligodendrocyte progenitors and their environment predict determinants of progenitor maintenance and differentiation. Ann Neurol 2006; 59:763-79. [PMID: 16634042 DOI: 10.1002/ana.20812] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Glial progenitor cells are abundant in adult human white matter. This study was designed to identify signaling pathways regulating their self-renewal and fate. METHODS We compared the transcriptional profiles of freshly sorted adult human white matter progenitor cells (WMPCs), purified by A2B5-based immunomagnetic sorting, with those of the white matter from which they derived. RESULTS We identified 132 genes differentially expressed by WMPCs; these included principal components of five receptor-defined signaling pathways, represented by platelet derived growth factor receptor alpha (PDGFRA) and type 3 fibroblast growth factor receptor (FGFR3), receptor tyrosine phosphatase-beta/zeta (RTPZ), notch, and syndecan3. WMPCs also differentially expressed the bone morphogenetic protein 4 (BMP4) inhibitors neuralin and BAMBI (BMP and activin membrane-bound inhibitor), suggesting tonic defense against BMP signaling. Differential overexpression of RTPZ was accompanied by that of its modulators pleiotrophin, NrCAM, tenascin, and the chondroitin sulfate proteoglycans, suggesting the importance of RTPZ signaling to WMPCs. When exposed to the RTPZ inhibitor bpV(phen), or lentiviral-shRNAi against RTPZ, WMPCs differentiated as oligodendrocytes. Conversely, when neuralin and BAMBI were antagonized by BMP4, astrocytic differentiation was induced, which was reversible by noggin. INTERPRETATION The RTPZ and BMP pathways regulate the self-maintenance of adult human WMPCs, and can be modulated to induce their oligodendrocytic or astrocytic differentiation. As such, they provide targets by which to productively mobilize resident progenitor cells of the adult human brain.
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Affiliation(s)
- Fraser J Sim
- Department of Neurology, University of Rochester Medical Center, NY 14642, USA
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31
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Foehr ED, Lorente G, Kuo J, Ram R, Nikolich K, Urfer R. Targeting of the receptor protein tyrosine phosphatase beta with a monoclonal antibody delays tumor growth in a glioblastoma model. Cancer Res 2006; 66:2271-8. [PMID: 16489031 DOI: 10.1158/0008-5472.can-05-1221] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The receptor protein tyrosine phosphatase beta (RPTPbeta) is a functional biomarker for several solid tumor types. RPTPbeta expression is largely restricted to the central nervous system and overexpressed primarily in astrocytic tumors. RPTPbeta is known to facilitate tumor cell adhesion and migration through interactions with extracellular matrix components and the growth factor pleiotrophin. Here, we show that RPTPbeta is expressed in a variety of solid tumor types with low expression in normal tissue. To assess RPTPbeta as a potential target for treatment of glioblastoma and other cancers, antibodies directed to RPTPbeta have been developed and profiled in vitro and in vivo. The recombinant extracellular domain of human short RPTPbeta was used to immunize mice and generate monoclonal antibodies that selectively recognize RPTPbeta and bind to the antigen with low nanomolar affinities. Moreover, these antibodies recognized the target on living tumor cells as measured by flow cytometry. These antibodies killed glioma cells in vitro when coupled to the cytotoxin saporin either directly or via a secondary antibody. Finally, in vivo studies showed that an anti-RPTPbeta immunotoxin (7E4B11-SAP) could significantly delay human U87 glioma tumors in a mouse xenograft model. Unconjugated 7E4B11 provides a modest but statistically significant tumor growth delay when delivered systemically in mice bearing U87 glioma tumors.
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Affiliation(s)
- Erik D Foehr
- AGY Therapeutics, Inc., South San Francisco, California 94080, USA.
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32
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Fodero-Tavoletti M, Hardy M, Cornell B, Katsis F, Sadek C, Mitchell C, Kemp B, Tiganis T. Protein tyrosine phosphatase hPTPN20a is targeted to sites of actin polymerization. Biochem J 2005; 389:343-54. [PMID: 15790311 PMCID: PMC1175111 DOI: 10.1042/bj20041932] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The human genome encodes 38 classical tyrosine-specific PTPs (protein tyrosine phosphatases). Many PTPs have been shown to regulate fundamental cellular processes and several are mutated in human diseases. We report that the product of the PTPN20 gene at the chromosome locus 10q11.2 is alternatively spliced to generate 16 possible variants of the classical human non-transmembrane PTP 20 (hPTPN20). One of these variants, hPTPN20a, was expressed in a wide range of both normal and transformed cell lines. The catalytic domain of hPTPN20 exhibited catalytic activity towards tyrosyl phosphorylated substrates, confirming that it is a bona fide PTP. In serum-starved COS1 cells, hPTPN20a was targeted to the nucleus and the microtubule network, colocalizing with the microtubule-organizing centre and intracellular membrane compartments, including the endoplasmic reticulum and the Golgi apparatus. Stimulation of cells with epidermal growth factor, osmotic shock, pervanadate, or integrin ligation targeted hPTPN20a to actin-rich structures that included membrane ruffles. The present study identifies hPTPN20a as a novel and widely expressed phosphatase with a dynamic subcellular distribution that is targeted to sites of actin polymerization.
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Affiliation(s)
| | - Matthew P. Hardy
- *Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Brent Cornell
- *Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Frosa Katsis
- †St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia
| | - Christine M. Sadek
- *Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Christina A. Mitchell
- *Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Bruce E. Kemp
- †St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia
- ‡CSIRO Health Sciences and Nutrition, Parkville, Victoria 3052, Australia
| | - Tony Tiganis
- *Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
- To whom correspondence should be addressed (email )
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Hayashi N, Oohira A, Miyata S. Synaptic localization of receptor-type protein tyrosine phosphatase zeta/beta in the cerebral and hippocampal neurons of adult rats. Brain Res 2005; 1050:163-9. [PMID: 15982644 DOI: 10.1016/j.brainres.2005.05.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Revised: 05/16/2005] [Accepted: 05/18/2005] [Indexed: 11/30/2022]
Abstract
Receptor-type protein tyrosine phosphatase (RPTP) zeta/beta is a nervous tissue-specific chondroitin sulfate proteoglycan. In this study, we investigated the immunohistochemical localization of RPTPzeta/beta in adult rat cerebral cortex and hippocampus at light and electron microscopic levels. Double labeling immunofluorescence microscopy revealed that the immunoreactivity of RPTPzeta/beta was observed at MAP2-positive dendrites and PSD-95-positive spines of pyramidal neurons in the cerebral cortex and hippocampus. Electron microscopic observation demonstrated a strong immunoreactivity of RPTPzeta/beta at the postsynaptic membrane of dendritic spines and shafts, and its moderate immunoreactivity at the dendritic membrane. In cultured cortical neurons, the immunoreactivity of RPTPzeta/beta was observed at some of PSD-95-positive spines. These results demonstrate that RPTPzeta/beta is localized mainly at the postsynaptic membrane of pyramidal neurons in adult cerebral cortex and hippocampus.
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Affiliation(s)
- Noriko Hayashi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585, Japan
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Heck N, Klausmeyer A, Faissner A, Garwood J. Cortical neurons express PSI, a novel isoform of phosphacan/RPTPbeta. Cell Tissue Res 2005; 321:323-33. [PMID: 16028071 DOI: 10.1007/s00441-005-1135-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Accepted: 04/11/2005] [Indexed: 01/06/2023]
Abstract
Phosphacan is a chondroitin sulfate proteoglycan representing the secreted extracellular part of a transmembrane receptor protein tyrosine phosphatase (RPTP-beta). These isoforms have been implicated in cell-extracellular matrix signaling events associated with myelination, axon growth, and cell migration in the developing central nervous system and may play critical roles in the context of brain pathologies. Recently, we have reported the identification of a new isoform of phosphacan, the phosphacan short isoform (PSI), the expression of which peaks in the second postnatal week. PSI interacts with the neuronal receptors L1 and F3/contactin and can promote neurite growth of cortical neurons. In this study, we have assessed, by in situ hybridization, the expression profile of PSI in the rat brain at postnatal day 7. PSI is largely expressed in the gray matter of the developing cerebral cortex in which it colocalizes with phosphacan, whereas the expression of RPTPbeta receptor forms is restricted to the ventricular area in which PSI has not been observed. Neurons from all layers of the cortex express PSI. In the cerebellum, on the other hand, no expression of PSI has been detected, although the other phosphacan/RPTP-beta isoforms show strong PSI expression here. Overall, our study suggests that PSI is expressed during the postnatal period in differentiated neurons of the cortex but is absent from structures in which proliferation and migration occur. The significance of these observations is discussed in the context of previous models of phosphacan/RPTP-beta functions.
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Affiliation(s)
- Nicolas Heck
- LNDR, CNRS Centre de Neurochimie, 67084, Strasbourg, France.
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Lorente G, Nelson A, Mueller S, Kuo J, Urfer R, Nikolich K, Foehr ED. Functional comparison of long and short splice forms of RPTPbeta: implications for glioblastoma treatment. Neuro Oncol 2005; 7:154-63. [PMID: 15831233 PMCID: PMC1871891 DOI: 10.1215/s1152851704000547] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The receptor protein tyrosine phosphatase beta (RPTPbeta/PTPzeta) is overexpressed in glioblastoma tumors and plays a functional role in tumor cell migration and adhesion. Glioblastomas express at least three splice variants of RPTPbeta, including long and short receptor forms and a secreted chondroitin sulfate proteoglycan called phosphacan. Here we explore the differences in the expression pattern and function of long RPTPbeta and short RPTPbeta. The short form of RPTPbeta lacks exon 12, which encodes 860 amino acids located in the extracellular domain. Until now, functional differences between long and short RPTPbeta have been difficult to elucidate. In this study, antibodies specific to the splice junction, unique to short RPTPbeta, allowed for the discrimination of the two receptors. A study of normal brain tissue and graded astrocytomas indicates that long and short RPTPbeta forms have an overlapping expression pattern. In order to study functional differences between long and short RPTPbeta, we created stable U87 glioblastoma cells that expressed these receptors. U87 stable cell lines overexpressing long or short RPTPbeta migrate faster and adhere more robustly than parental U87 cells. The two forms differ in that long-RPTPbeta-overexpressing cells migrate and adhere better than short-RPTPbeta-overexpressing cells. A study of the extracellular domain of short RPTPbeta indicates that it retains much of the functional capacity of phosphacan. Indeed, the action of recombinant, short-RPTPbeta extracellular domain protein is similar to that of phosphacan as a repulsive substrate for glioblastoma cells. Comparison of the signaling capacity of long RPTPbeta to that of short RPTPbeta reveals very similar abilities to activate transcription pathways. Moreover, transient transfection with either long or short RPTPbeta activates NF-kappaB reporter gene transcription. Because of their tumor-restricted and largely overlapping expression patterns in glioblastoma, both RPTPbeta splice forms are potential therapeutic targets. The involvement of long and short RPTPbeta in glioma tumor cell biology also contributes to the value of RPTPbeta as a cancer target.
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Affiliation(s)
| | | | | | | | | | | | - Erik D. Foehr
- Address correspondence to Erik D. Foehr, AGY Therapeutics, Inc., 270 East Grand Avenue, South San Francisco, CA 94080, USA (
)
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Abstract
Proteoglycans, as part of the extracellular or cell-surface milieu of most tissues and organ systems, play important roles in morphogenesis by modulating cell-matrix or cell-cell interactions, cell adhesiveness, or by binding and presenting growth and differentiation factors. Chondroitin sulfate proteoglycans which constitute the major population of proteoglycans in the central nervous system may influence formation of neuronal nuclei, establishment of boundaries for axonal growth and act as modulators of neuronal outgrowth during brain development, as well as during regeneration after injury. There is a paucity of information on the role of chondroitin sulfate proteoglycans in central nervous system organogenesis. In the chick embryo, aggrecan has a regionally specific and developmentally regulated expression profile during brain development. By Northern and Western blot analysis, aggrecan expression is first detected in chick brain on embryonic day 7 (E7), increases from E7 to E13, declines markedly after E16, and is not evident in hatchling brains. The time course and pattern of aggrecan expression observed in ventricular zone cells suggested that it might play a role in gliogenesis. We have analyzed the role of aggrecan during brain development using a aggrecan-deficient model, nanomelia. In nanomelic chicks, expression and levels of neurocan and brevican is not affected, indicating a non-redundant role for these members of the aggrecan gene family. Our analysis of the aggrecan-deficient model found a severely altered phenotype which affects cell behavior in a neuronal culture paradigm and expression of astrocytic markers in vivo . Taken together our results suggest a function for aggrecan in the specification of a sub-set of glia precursors that might give rise to astrocytes in vivo.
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Affiliation(s)
- Nancy B Schwartz
- Department of Pediatrics, Committee on Developmental Biology, The University of Chicago, Chicago, IL 60637, USA.
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Hayashi N, Miyata S, Yamada M, Kamei K, Oohira A. Neuronal expression of the chondroitin sulfate proteoglycans receptor-type protein-tyrosine phosphatase beta and phosphacan. Neuroscience 2005; 131:331-48. [PMID: 15708477 DOI: 10.1016/j.neuroscience.2004.11.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2004] [Indexed: 12/30/2022]
Abstract
Receptor-type protein-tyrosine phosphatase beta (RPTPbeta) and its spliced variant phosphacan are major components of chondroitin sulfate proteoglycans in the CNS. In this study, expression and localization of RPTPbeta and phosphacan were examined in developing neurons by immunological analyses using 6B4, 3F8, and anti-PTP antibodies and reverse transcription-polymerase chain reaction (RT-PCR). Light microscopic immunohistochemistry showed that 6B4 RPTPbeta/phosphacan immunoreactivity was observed around neurons in the cortical plate. Further ultrastructural observation showed that 6B4 RPTPbeta/phosphacan immunoreactivity was observed mainly at the membrane of migrating neurons and radial glia. Immunocytochemical analysis revealed that RPTPbeta immunoreactivity was observed in cultured cerebral, hippocampal, and cerebellar neurons in addition to type-1 and type-2 astrocytes. Western analysis further demonstrated that the shorter receptor form of RPTPbeta (sRPTPbeta) was detected from cell lysate of cortical and hippocampal neurons using 6B4 and anti-PTP antibodies, while sRPTPbeta of cerebellar neurons and type-1 astrocytes was recognized only by anti-PTP antibody. Phosphacan was detected from neuronal culture supernatants of cortical, hippocampal, and cerebellar neurons, but not from type-1 astrocytes using 6B4 and 3F8 antibodies. RT-PCR analysis demonstrated the prominent expression of sRPTPbeta and phosphacan mRNAs in cortical neurons, and that of sRPTPbeta mRNA in type-1 astrocytes. During culture development of cortical neurons, the immunoreactivity of 6B4 sRPTPbeta was observed entirely on the neuronal surface including somata, dendrites, axons, and growth cones at earlier stages of cortical neuronal culture such as stages 2 and 3, while, after longer culture, 6B4 sRPTPbeta immunoreactivity in stages 4 and 5 neurons was detected at dendrites and somata and disappeared from axons, and was not observed over axonal terminals and postsynaptic spines. These results demonstrate that neurons are able to express sRPTPbeta on their cellular surface and to secrete phosphacan, and neuronal expression of sRPTPbeta may modulate neuronal differentiation including neuritogenesis and synaptogenesis.
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Affiliation(s)
- N Hayashi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Müller S, Lamszus K, Nikolich K, Westphal M. Receptor protein tyrosine phosphatase ζ as a therapeutic target for glioblastoma therapy. Expert Opin Ther Targets 2005; 8:211-20. [PMID: 15161428 DOI: 10.1517/14728222.8.3.211] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Astrocytomas are the most frequent brain tumour type in adults. The most common astrocytoma is the glioblastoma (GBM), which is also the most malignant and refractory to treatment--ultimately leading to the patient's death within a year of diagnosis. Neither the classical nor more experimental therapeutic approaches have significantly improved the clinical outcome of this disease. Expression profile analysis of primary tumours has provided recent insight into the identification of new GBM therapeutic targets. These proteins serve as excellent candidates to either inhibit the target molecule's functions (e.g., angiogenesis, migration or proliferation) or, coupled with a toxin or radionucleotide, to bind and exterminate the tumour cells. The receptor protein tyrosine phosphatase zeta (RPTPzeta) and one of its main ligands, pleiotropin (Ptn), are overexpressed in GBMs, thus making them potentially very good targets for the development of new immunotherapeutics. This review will summarise recent advances in GBM therapies focusing on RPTPzeta as a target for immunotherapeutics.
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Affiliation(s)
- Sabine Müller
- AGY Therapeutics, 270 East Grant Avenue, South San Francisco, CA 94080, USA.
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Carulli D, Rhodes KE, Brown DJ, Bonnert TP, Pollack SJ, Oliver K, Strata P, Fawcett JW. Composition of perineuronal nets in the adult rat cerebellum and the cellular origin of their components. J Comp Neurol 2005; 494:559-77. [PMID: 16374793 DOI: 10.1002/cne.20822] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The decrease in plasticity that occurs in the central nervous system during postnatal development is accompanied by the appearance of perineuronal nets (PNNs) around the cell body and dendrites of many classes of neuron. These structures are composed of extracellular matrix molecules, such as chondroitin sulfate proteoglycans (CSPGs), hyaluronan (HA), tenascin-R, and link proteins. To elucidate the role played by neurons and glial cells in constructing PNNs, we studied the expression of PNN components in the adult rat cerebellum by immunohistochemistry and in situ hybridization. In the deep cerebellar nuclei, only large excitatory neurons were surrounded by nets, which contained the CSPGs aggrecan, neurocan, brevican, versican, and phosphacan, along with tenascin-R and HA. Whereas both net-bearing neurons and glial cells were the sources of CSPGs and tenascin-R, only the neurons expressed the mRNA for HA synthases (HASs), cartilage link protein, and link protein Bral2. In the cerebellar cortex, Golgi neurons possessed PNNs and also synthesized HASs, cartilage link protein, and Bral2 mRNAs. To see whether HA might link PNNs to the neuronal cell surface by binding to a receptor, we investigated the expression of the HA receptors CD44, RHAMM, and LYVE-1. No immunolabelling for HA receptors on the membrane of net-bearing neurons was found. We therefore propose that HASs, which can retain HA on the cell surface, may act as a link between PNNs and neurons. Thus, HAS and link proteins might be key molecules for PNN formation and stability.
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Affiliation(s)
- Daniela Carulli
- Cambridge Centre for Brain Repair, University of Cambridge, Cambridge CB2 2PY, United Kingdom
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Sim FJ, Goldman SA. White matter progenitor cells reside in an oligodendrogenic niche. ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2005:61-81. [PMID: 16315609 DOI: 10.1007/3-540-27626-2_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- F J Sim
- Dicision of Cell and Gene Therapy, Department of Neurology, University of Rochester Medical Center, NY 14642, USA
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Sandvig A, Berry M, Barrett LB, Butt A, Logan A. Myelin-, reactive glia-, and scar-derived CNS axon growth inhibitors: expression, receptor signaling, and correlation with axon regeneration. Glia 2004; 46:225-51. [PMID: 15048847 DOI: 10.1002/glia.10315] [Citation(s) in RCA: 285] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Axon regeneration is arrested in the injured central nervous system (CNS) by axon growth-inhibitory ligands expressed in oligodendrocytes/myelin, NG2-glia, and reactive astrocytes in the lesion and degenerating tracts, and by fibroblasts in scar tissue. Growth cone receptors (Rc) bind inhibitory ligands, activating a Rho-family GTPase intracellular signaling pathway that disrupts the actin cytoskeleton inducing growth cone collapse/repulsion. The known inhibitory ligands include the chondroitin sulfate proteoglycans (CSPG) Neurocan, Brevican, Phosphacan, Tenascin, and NG2, as either membrane-bound or secreted molecules; Ephrins expressed on astrocyte/fibroblast membranes; the myelin/oligodendrocyte-derived growth inhibitors Nogo, MAG, and OMgp; and membrane-bound semaphorins (Sema) produced by meningeal fibroblasts invading the scar. No definitive CSPG Rc have been identified, although intracellular signaling through the Rho family of G-proteins is probably common to all the inhibitory ligands. Ephrins bind to signalling Ephs. The ligand-binding Rc for all the myelin inhibitors is NgR and requires p75(NTR) for transmembrane signaling. The neuropilin (NP)/plexin (Plex) Rc complex binds Sema. Strategies for promoting axon growth after CNS injury are thwarted by the plethora of inhibitory ligands and the ligand promiscuity of some of their Rc. There is also paradoxical reciprocal expression of many of the inhibitory ligands/Rc in normal and damaged neurons, and NgR expression is restricted to a limited number of neuronal populations. All these factors, together with an incomplete understanding of the normal functions of many of these molecules in the intact CNS, presently confound interpretive acumen in regenerative studies.
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Affiliation(s)
- Axel Sandvig
- Laboratory of Regenerative Neurobiology, Institute for Experimental Medical Research, Ullevål University Hospital, Oslo, Norway.
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Carulli D, Buffo A, Strata P. Reparative mechanisms in the cerebellar cortex. Prog Neurobiol 2004; 72:373-98. [PMID: 15177783 DOI: 10.1016/j.pneurobio.2004.03.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Accepted: 03/17/2004] [Indexed: 11/28/2022]
Abstract
In the adult brain, different neuronal populations display different degrees of plasticity. Here, we describe the highly different plastic properties of inferior olivary neurones and Purkinje cells. Olivary neurones show a basal expression of growth-associated proteins, such as GAP-43 and Krox24/EGR-1, and remarkable remodelling capabilities of their terminal arbour. They also regenerate their transected neurites into growth-permissive territories and may reinnervate the lost target. Sprouting and regrowing olivary axons are able to follow specific positional information cues to establish new connections according to the original projection map. In addition, they set a strong cell body reaction to injury, which in specific olivary subsets is regulated by inhibitory target-derived cues. In contrast, Purkinje cells do not have a constitutive level of growth-associated genes, and show little cell body reaction, no axonal regeneration after axotomy, and weak sprouting capabilities. Block of myelin-derived signals allows terminal arbour remodelling, but not regeneration, while selective over-expression of GAP-43 induces axonal sprouting along the axonal surface and at the level of the lesion. We suggest that the high constitutive intrinsic plasticity of the inferior olive neurones allows their terminal arbour to sustain the activity-dependent ongoing competition with the parallel fibres in order to maintain the post-synaptic territory, and possibly underlies mechanisms of learning and memory. Such a plasticity is used also as a reparative mechanism following axotomy. In contrast, in Purkinje cells, poor intrinsic regenerative capabilities and myelin-derived signals stabilise the mature connectivity and prevent axonal regeneration after lesion.
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Affiliation(s)
- Daniela Carulli
- Department of Neuroscience, Rita Levi Montalcini Center for Brain Repair, University of Turin, C.so Raffaello 30, 10125 Turin, Italy
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43
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Ivanova A, Agochiya M, Amoyel M, Richardson WD. Receptor tyrosine phosphatase zeta/beta in astrocyte progenitors in the developing chick spinal cord. Gene Expr Patterns 2004; 4:161-6. [PMID: 15161096 DOI: 10.1016/j.modgep.2003.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2003] [Revised: 09/08/2003] [Accepted: 09/09/2003] [Indexed: 10/27/2022]
Abstract
We cloned a cDNA encoding the receptor-type protein tyrosine phosphatase zeta/beta (RPTPZ/beta) from embryonic chick spinal cord. RPTPZ/beta was expressed throughout the ventricular zone (VZ) of the developing spinal cord and in scattered cells outside the VZ. Platelet-derived growth factor receptor alpha (PDGFRa)-positive oligodendrocyte progenitors co-expressed RPTPZ/beta within the VZ but down-regulated RPTPZ/beta after leaving the VZ. Most RPTPZ/beta-positive cells outside the VZ co-expressed glutamine synthetase and fibroblast growth factor receptor-3, indicating that they are astrocyte progenitors. Northern blot analysis revealed a single approximately 9 kbp RPTPZ/beta transcript expressed in the embryonic chick spinal cord, indicating that the shorter alternative-splice products of RPTPZ/beta found in rodent spinal cord and brain--including the abundant extracellular proteoglycan known as phosphacan--are not present in the embryonic chick spinal cord.
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Affiliation(s)
- Anna Ivanova
- Wolfson Institute for Biomedical Research, Department of Biology, University College London, Gower Street, London WC1E 6BT, UK
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Dobbertin A, Rhodes KE, Garwood J, Properzi F, Heck N, Rogers JH, Fawcett JW, Faissner A. Regulation of RPTPbeta/phosphacan expression and glycosaminoglycan epitopes in injured brain and cytokine-treated glia. Mol Cell Neurosci 2004; 24:951-71. [PMID: 14697661 DOI: 10.1016/s1044-7431(03)00257-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Several chondroitin sulfate proteoglycans (CSPGs) are upregulated after CNS injury and are thought to limit axonal regeneration in the adult mammalian CNS. Therefore, we examined the expression of the CSPG, receptor protein tyrosine phosphatase beta (RPTPbeta)/phosphacan, after a knife lesion to the cerebral cortex and after treatment of glial cultures with regulatory factors. The three splice variants of this CSPG gene, the secreted isoform, phosphacan, and the two transmembrane isoforms, the long and short RPTPbeta, were examined. Western blot and immunostaining analysis of injured and uninjured tissue revealed a transient decrease of phosphacan protein levels, but not of short RPTPbeta, in the injured tissue from 1 to 7 days postlesion (dpl). By real time RT-PCR, we show that phosphacan and long RPTPbeta mRNA levels are transiently down-regulated at 2 dpl, unlike those of short RPTPbeta which increased after 4 dpl. In contrast to the core glycoprotein, the phosphacan chondroitin sulfate (CS) glycosaminoglycan epitope DSD-1 was up-regulated after 7 dpl. Phosphacan was expressed by cultivated astrocytes and oligodendrocyte precursors but was more glycanated in oligodendrocyte precursors, which produce more of DSD-1 epitope than astrocytes. Epidermal growth factor/transforming growth factor alpha strongly increased the astrocytic expression of long RPTPbeta and phosphacan and slightly the short RPTPbeta protein levels, while interferon gamma and tumor necrosis factor alpha reduced astrocytic levels of phosphacan, but not of the receptor forms. Examining the effects of phosphacan on axon growth from rat E17 cortical neurons, we found that phosphacan stimulates outgrowth in a largely CS dependent manner, while it blocks the outgrowth-promoting effects of laminin through an interaction that is not affected by removal of the CS chains. These results demonstrate complex injury-induced modifications in phosphacan expression and glycanation that may well influence axonal regeneration and repair processes in the damaged CNS.
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Affiliation(s)
- Alexandre Dobbertin
- Physiological Laboratory, University of Cambridge, CB2 3EG Cambridge, and Centre for Brain Repair, Forvie Site, Cambridge CB2 2PY, UK
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Garwood J, Heck N, Reichardt F, Faissner A. Phosphacan short isoform, a novel non-proteoglycan variant of phosphacan/receptor protein tyrosine phosphatase-beta, interacts with neuronal receptors and promotes neurite outgrowth. J Biol Chem 2003; 278:24164-73. [PMID: 12700241 DOI: 10.1074/jbc.m211721200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Phosphacan, one of the principal proteoglycans in the extracellular matrix of the central nervous system, is implicated in neuron-glia interactions associated with neuronal differentiation and myelination. We report here the identification of a novel truncated form of phosphacan, phosphacan short isoform (PSI), that corresponds to the N-terminal carbonic anhydrase- and fibronectin type III-like domains and half of the spacer region. The novel cDNA transcript was isolated by screening of a neonatal brain cDNA expression library using a polyclonal antibody raised against phosphacan. Expression of this transcript in vivo was confirmed by Northern blot hybridization. Analysis of brain protein extracts reveals the presence of a 90-kDa glycosylated protein in the phosphate-buffered saline-insoluble 100000 x g fraction that reacts with antisera against both phosphacan and a recombinant PSI protein and that has the predicted N-terminal sequence. This protein is post-translationally modified with oligosaccharides, including the HNK-1 epitope, but, unlike phosphacan, it is not a proteoglycan. The expression of the PSI protein varies during central nervous system development in a fashion similar to that observed for phosphacan, being first detected around embryonic day 16 and then showing a dramatic increase in expression to plateau around the second week post-natal. Both the native and recombinant PSI protein can interact with the Ig cell adhesion molecules, F3/contactin and L1, and in neurite outgrowth assays, the PSI protein can promote outgrowth of cortical neurons when used as a coated substrate. Hence, the identification of this novel isoform of phosphacan/receptor protein tyrosine phosphatase-beta provides a new component in cell-cell and cell-extracellular matrix signaling events in which these proteins have been implicated.
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Affiliation(s)
- Jeremy Garwood
- Laboratoire de Neurobiologie du Développement et de la Régénération, CNRS Centre de Neurochimie, 67084 Strasbourg, France.
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Hida H, Jung CG, Wu CZ, Kim HJ, Kodama Y, Masuda T, Nishino H. Pleiotrophin exhibits a trophic effect on survival of dopaminergic neurons in vitro. Eur J Neurosci 2003; 17:2127-34. [PMID: 12786979 DOI: 10.1046/j.1460-9568.2003.02661.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To understand what kind of trophic factors are up-regulated in dopamine (DA)-depleted striatum, we first analysed the up-regulation of mRNAs using a DNA microarray in DA-depleted striatum where DAergic inputs were denervated by 6-OHDA. We then investigated whether or not such trophic factors had an effect on cultured dopaminergic neurons. The microarray analysis revealed that pleiotrophin (PTN), glial-derived neurotopic factor (GDNF) and others were up-regulated in DA-depleted striatum. As PTN has been reported to have a wide range of trophic effects on neurons, we focused on the functional role of PTN in the present study. The increase in PTN mRNA was confirmed by Northern blotting at 1-3 weeks after the lesion, reaching a peak at 1 week. In embryonic day 15 mesencephalic neuron culture, PTN increased the number of tyrosine hydroxylase (TH) -positive neurons in a dose-dependent manner (125.2 +/- 2.0% of the control at 50 ng/mL), while a family protein, midkine (10 ng/mL) did not show any trophic effect (99.3 +/- 0.7%). In addition, the PTN effect on DAergic neurons was additive to the GDNF effect. As PTN did not increase the number of microtubule-associated protein-2 (MAP 2)-positive neurons or promote the proliferation of dopaminergic progenitors in a bromodeoxyuridine (BrdU) labelling study, the effect appeared to enhance the specific survival of dopaminergic neurons. Expression of PTN receptors (syndecan-3, PTP-zeta) was detected on the cultured mesencephalic neurons, and also up-regulated in DA-depleted striatum. The data indicate that PTN is up-regulated in DA-depleted striatum and exhibits a trophic effect specifically on the survival of cultured dopaminergic neurons.
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Affiliation(s)
- Hideki Hida
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Kawasumi 1, Mizuho-Ku, Nagoya 467-8601, Japan.
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Morgenstern DA, Asher RA, Fawcett JW. Chondroitin sulphate proteoglycans in the CNS injury response. PROGRESS IN BRAIN RESEARCH 2002; 137:313-32. [PMID: 12440375 DOI: 10.1016/s0079-6123(02)37024-9] [Citation(s) in RCA: 345] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
As the preceding discussion has demonstrated, experimental data now indicate that the expression of a number of different CSPGs is increased following CNS injury. The hyalectans neurocan, versican and [figure: see text] brevican, plus NG2 and phosphacan are upregulated following injury and all have been shown to exhibit inhibitory effects on neurite outgrowth in vitro. It is likely therefore that the increased expression of these molecules contributes to the non-permissive nature of the glial scar. The relative contributions of individual molecules remain, however, to be determined. It is important to remember also that not only does the glial scar contain many different inhibitory molecules, but that these are the products of a number of different cells, including not just astrocytes, but also oligodendrocyte progenitor and meningeal cells. It is arguable that the latter two cell types make a greater contribution than astrocytes to the inhibitory environment of the injured CNS. Recently, attempts have been made to alter the CSPG component of the glial scar in the hope that this will facilitate improved axonal regeneration. Three studies (Bradbury et al., 2002; Yick et al., 2000; Moon et al., 2001) have reported an improved regenerative response following treatment of the injured CNS with chondroitinase ABC. CSPGs represent a significant source of inhibition within the injured CNS; these studies indicate that successful CNS regeneration may be brought about by interventions which target these molecules and/or the cells which produce them.
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Affiliation(s)
- Daniel A Morgenstern
- Physiological Laboratory, Centre for Brain Repair, Cambridge University, E.D. Adrian Building, Forvie Site, Robinson Way, Cambridge CB2 2PY, UK
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Harroch S, Furtado GC, Brueck W, Rosenbluth J, Lafaille J, Chao M, Buxbaum JD, Schlessinger J. A critical role for the protein tyrosine phosphatase receptor type Z in functional recovery from demyelinating lesions. Nat Genet 2002; 32:411-4. [PMID: 12355066 DOI: 10.1038/ng1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2002] [Accepted: 08/12/2002] [Indexed: 02/03/2023]
Abstract
Several lines of evidence suggest that tyrosine phosphorylation is a key element in myelin formation, differentiation of oligodendrocytes and Schwann cells, and recovery from demyelinating lesions. Multiple sclerosis is a demyelinating disease of the human central nervous system, and studies of experimental demyelination indicate that remyelination in vivo requires the local generation, migration or maturation of new oligodendrocytes, or some combination of these. Failure of remyelination in multiple sclerosis could result from the failure of any of these processes or from the death of oligodendrocytes. Ptprz encodes protein tyrosine phosphatase receptor type Z (Ptpz, also designated Rptpbeta), which is expressed primarily in the nervous system but also in oligodendrocytes, astrocytes and neurons. Here we examine the susceptibility of mice deficient in Ptprz to experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. We observe that mice deficient in Ptprz show impaired recovery from EAE induced by myelin oligodendrocyte glycoprotein (MOG) peptide. This sustained paralysis is associated with increased apoptosis of mature oligodendrocytes in the spinal cords of mutant mice at the peak of inflammation. We further demonstrate that expression of PTPRZ1, the human homolog of Ptprz, is induced in multiple sclerosis lesions and that the gene is specifically expressed in remyelinating oligodendrocytes in these lesions. These results support a role for Ptprz in oligodendrocyte survival and in recovery from demyelinating disease.
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Affiliation(s)
- Sheila Harroch
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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Miyata S, Shinga I, Taguchi K, Nakashima T, Kiyohara T, Oohira A. Chondroitin sulfate proteoglycan phosphacan/RPTPbeta in the hypothalamic magnocellular nuclei. Brain Res 2002; 949:112-21. [PMID: 12213306 DOI: 10.1016/s0006-8993(02)02971-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hypothalamo-neurohypophysial system synthesizes and releases arginine vasopressin (AVP) and oxytocin (OXT) with physiological stimulation. In the present study, we investigated localization of a chondroitin sulfate proteoglycan (CSPG), phosphacan/RPTPbeta, in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of adult rats at both the light and electron microscopic levels. Immunohistochemical analyses demonstrated stronger phosphacan/RPTPbeta immunoreactivity within the SON and PVN compared with adjacent hypothalamic areas. Double labeling experiments showed phosphacan/RPTPbeta immunoreactivity constituting punctate networks to surround the somata and dendrites of AVP- and OXT-secreting magnocellular neurons. Electron microscopic examination further revealed strong phosphacan/RPTPbeta immunoreactivity at extracellular membrane surface of some axons, somata, and dendrites of the SON, but not of synaptic junctions. Interestingly, phosphacan/RPTPbeta immunoreactivity was also observed at extracellular surface membrane between astrocytic processes and neurons rather than between magnocellular neurons. The present results indicate the high expression of the CSPG, phosphacan/RPTPbeta at the extracellular space in the hypothalamic AVP- and OXT-secreting magnocellular neurons.
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Affiliation(s)
- Seiji Miyata
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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50
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Chen ZJ, Ughrin Y, Levine JM. Inhibition of axon growth by oligodendrocyte precursor cells. Mol Cell Neurosci 2002; 20:125-39. [PMID: 12056844 DOI: 10.1006/mcne.2002.1102] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The glial scar that forms at the site of injury is thought to be a biochemical and physical barrier to successful regeneration, although the molecules responsible for this barrier function are not well understood. Glia scars contain large numbers of oligodendrocyte precursor cells (OPCs) and these cells can produce several different growth-inhibitory chondroitin sulfate proteoglycans (CSPGs), including NG2, neurocan, and phosphacan. Here, we used membrane-based assays to show that the surface of OPCs is both nonpermissive and inhibitory for neurite outgrowth. Inhibition of growth by OPC is reversed by treatment with antibodies against the NG2 CSPG and the expression of NG2 is sufficient to change a growth-permissive cell surface to a nonpermissive surface. These result suggest that the OPCs that accumulate rapidly at sites of CNS injury can contribute to the creation of an environment that inhibits nerve regeneration and that NG2 is a necessary feature of that environment.
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Affiliation(s)
- Zhi Jiang Chen
- Department of Neurobiology and Behavior, SUNY at Stony Brook, New York 11794, USA
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