1
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Appeltshauser L, Linke J, Heil HS, Karus C, Schenk J, Hemmen K, Sommer C, Doppler K, Heinze KG. Super-resolution imaging pinpoints the periodic ultrastructure at the human node of Ranvier and its disruption in patients with polyneuropathy. Neurobiol Dis 2023; 182:106139. [PMID: 37146836 DOI: 10.1016/j.nbd.2023.106139] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
The node of Ranvier is the key element in saltatory conduction along myelinated axons, but its specific protein organization remains elusive in the human species. To shed light on nanoscale anatomy of the human node of Ranvier in health and disease, we assessed human nerve biopsies of patients with polyneuropathy by super-resolution fluorescence microscopy. We applied direct stochastic optical reconstruction microscopy (dSTORM) and supported our data by high-content confocal imaging combined with deep learning-based analysis. As a result, we revealed a ~ 190 nm periodic protein arrangement of cytoskeletal proteins and axoglial cell adhesion molecules in human peripheral nerves. In patients with polyneuropathy, periodic distances increased at the paranodal region of the node of Ranvier, both at the axonal cytoskeleton and at the axoglial junction. In-depth image analysis revealed a partial loss of proteins of the axoglial complex (Caspr-1, neurofascin-155) in combination with detachment from the cytoskeletal anchor protein ß2-spectrin. High content analysis showed that such paranodal disorganization occurred especially in acute and severe axonal neuropathy with ongoing Wallerian degeneration and related cytoskeletal damage. We provide nanoscale and protein-specific evidence for the prominent, but vulnerable role of the node of Ranvier for axonal integrity. Furthermore, we show that super-resolution imaging can identify, quantify and map elongated periodic protein distances and protein interaction in histopathological tissue samples. We thus introduce a promising tool for further translational applications of super resolution microscopy.
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Affiliation(s)
| | - Janis Linke
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany; Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Hannah S Heil
- Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany; Optical Cell Biology, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Christine Karus
- Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Joachim Schenk
- Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Katherina Hemmen
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Claudia Sommer
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Kathrin Doppler
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany.
| | - Katrin G Heinze
- Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany.
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2
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Middleton SJ, Perez-Sanchez J, Dawes JM. The structure of sensory afferent compartments in health and disease. J Anat 2021; 241:1186-1210. [PMID: 34528255 PMCID: PMC9558153 DOI: 10.1111/joa.13544] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 12/20/2022] Open
Abstract
Primary sensory neurons are a heterogeneous population of cells able to respond to both innocuous and noxious stimuli. Like most neurons they are highly compartmentalised, allowing them to detect, convey and transfer sensory information. These compartments include specialised sensory endings in the skin, the nodes of Ranvier in myelinated axons, the cell soma and their central terminals in the spinal cord. In this review, we will highlight the importance of these compartments to primary afferent function, describe how these structures are compromised following nerve damage and how this relates to neuropathic pain.
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Affiliation(s)
- Steven J Middleton
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - John M Dawes
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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3
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Elazar N, Vainshtein A, Rechav K, Tsoory M, Eshed-Eisenbach Y, Peles E. Coordinated internodal and paranodal adhesion controls accurate myelination by oligodendrocytes. J Cell Biol 2019; 218:2887-2895. [PMID: 31451613 PMCID: PMC6719437 DOI: 10.1083/jcb.201906099] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 01/09/2023] Open
Abstract
Elazar et al. show that reduced axoglial adhesion at both the paranodal junction and the internodes results in the formation of multimyelinated axons. Their findings demonstrate that accurate ensheathment by oligodendrocytes depends on the coordinated action of these different adhesion systems. Oligodendrocyte–axon contact is mediated by several cell adhesion molecules (CAMs) that are positioned at distinct sites along the myelin unit, yet their role during myelination remains unclear. Cadm4 and its axonal receptors, Cadm2 and Cadm3, as well as myelin-associated glycoprotein (MAG), are enriched at the internodes below the compact myelin, whereas NF155, which binds the axonal Caspr/contactin complex, is located at the paranodal junction that is formed between the axon and the terminal loops of the myelin sheath. Here we report that Cadm4-, MAG-, and Caspr-mediated adhesion cooperate during myelin membrane ensheathment. Genetic deletion of either Cadm4 and MAG or Cadm4 and Caspr resulted in the formation of multimyelinated axons due to overgrowth of the myelin away from the axon and the forming paranodal junction. Consequently, these mice displayed paranodal loops either above or underneath compact myelin. Our results demonstrate that accurate placement of the myelin sheath by oligodendrocytes requires the coordinated action of internodal and paranodal CAMs.
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Affiliation(s)
- Nimrod Elazar
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Anya Vainshtein
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Katya Rechav
- Electron Microscopy Unit, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Tsoory
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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4
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Kim JY, Yoon JY, Sugiura Y, Lee SK, Park JD, Song GJ, Yang HJ. Dendropanax morbiferus leaf extract facilitates oligodendrocyte development. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190266. [PMID: 31312492 PMCID: PMC6599778 DOI: 10.1098/rsos.190266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/04/2019] [Indexed: 06/10/2023]
Abstract
Treatment of multiple sclerosis is effective when anti-inflammatory, neuroprotective and regenerative strategies are combined. Dendropanax morbiferus (DM) has anti-inflammatory, anti-oxidative properties, which may be beneficial for multiple sclerosis. However, there have been no reports on the effects of DM on myelination, which is critical for regenerative processes. To know whether DM benefits myelination, we checked differentiation and myelination of oligodendrocytes (OLs) in various primary culture systems treated with DM leaf EtOH extracts or control. DM extracts increased the OL membrane size in the mixed glial and pure OL precursor cell (OPC) cultures and changed OL-lineage gene expression patterns in the OPC cultures. Western blot analysis of DM-treated OPC cultures showed upregulation of MBP and phosphorylation of ERK1/2. In myelinating cocultures, DM extracts enhanced OL differentiation, followed by increased axonal contacts and myelin gene upregulations such as Myrf, CNP and PLP. Phytochemical analysis by LC-MS/MS identified multiple components from DM extracts, containing bioactive molecules such as quercetin, cannabidiol, etc. Our results suggest DM extracts enhance OL differentiation, followed by an increase in membrane size and axonal contacts, thereby indicating enhanced myelination. In addition, we found that DM extracts contain multiple bioactive components, warranting further studies in relation to finding effective components for enhancing myelination.
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Affiliation(s)
- Ji-Young Kim
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul 120-749, Republic of Korea
| | - Ju-Young Yoon
- Department of Integrative Biosciences, University of Brain Education, Cheonan 31228, Republic of Korea
| | - Yuki Sugiura
- Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Soo-Kyoung Lee
- Department of Health Science and Daily Sports, Global Cyber University, Cheonan 31228, Republic of Korea
| | - Jae-Don Park
- Cheju Halla University, Jeju 63092, Republic of Korea
| | - Gyun-Jee Song
- Department of Medical Science, International St Mary's Hospital, Catholic Kwandong University, Gangneung, Republic of Korea
| | - Hyun-Jeong Yang
- Department of Integrative Biosciences, University of Brain Education, Cheonan 31228, Republic of Korea
- Korea Institute of Brain Science, Seoul, Republic of Korea
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5
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Manso C, Querol L, Lleixà C, Poncelet M, Mekaouche M, Vallat JM, Illa I, Devaux JJ. Anti-Neurofascin-155 IgG4 antibodies prevent paranodal complex formation in vivo. J Clin Invest 2019; 129:2222-2236. [PMID: 30869655 DOI: 10.1172/jci124694] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Neurofascin-155 (Nfasc155) is an essential glial cell adhesion molecule expressed in paranodal septate-like junctions of peripheral and central myelinated axons. The genetic deletion of Nfasc155 results in the loss of septate-like junctions and in conduction slowing. In humans, IgG4 antibodies against Nfasc155 are implicated in the pathogenesis of chronic inflammatory demyelinating polyneuropathy (CIDP). These antibodies are associated with an aggressive onset, a refractoriness to intravenous immunoglobulin, and tremor of possible cerebellar origin. Here, we examined the pathogenic effects of patient-derived anti-Nfasc155 IgG4. These antibodies did not inhibit the ability of Nfasc155 to complex with its axonal partners contactin-1/CASPR1 or induce target internalization. Passive transfer experiments revealed that IgG4 antibodies target Nfasc155 on Schwann cell surface, and diminished Nfasc155 protein levels and prevented paranodal complex formation in neonatal animals. In adult animals, chronic intrathecal infusions of antibodies also induced the loss of Nfasc155 and of paranodal specialization and resulted in conduction alterations in motor nerves. These results indicate that anti-Nfasc155 IgG4 perturb conduction in absence of demyelination, validating the existence of paranodopathy. These results also shed light on the mechanisms regulating protein insertion at paranodes.
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Affiliation(s)
- Constance Manso
- Aix Marseille Université, CNRS, CRN2M-UMR7286, Marseille, France.,Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR5297, Bordeaux, France
| | - Luis Querol
- Neuromuscular Diseases Unit, Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Barcelona, Spain.,Centro para la Investigación en Red en Enfermedades Raras (CIBERER), Madrid, Spain
| | - Cinta Lleixà
- Neuromuscular Diseases Unit, Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Barcelona, Spain.,Centro para la Investigación en Red en Enfermedades Raras (CIBERER), Madrid, Spain
| | - Mallory Poncelet
- Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier University, Hopital Gui de Chauliac, Montpellier, France
| | - Mourad Mekaouche
- Aix Marseille Université, CNRS, CRN2M-UMR7286, Marseille, France.,Aix Marseille Université, CNRS, INP UMR7051, Marseille, France
| | - Jean-Michel Vallat
- National Reference Center for "rare peripheral neuropathies" and Department of Neurology, University Hospital, Limoges, France
| | - Isabel Illa
- Neuromuscular Diseases Unit, Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Barcelona, Spain.,Centro para la Investigación en Red en Enfermedades Raras (CIBERER), Madrid, Spain
| | - Jérôme J Devaux
- Aix Marseille Université, CNRS, CRN2M-UMR7286, Marseille, France.,Institute for Neurosciences of Montpellier, INSERM U1051, Montpellier University, Hopital Gui de Chauliac, Montpellier, France
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6
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Sekizar S, Williams A. Ex Vivo Slice Cultures to Study Myelination, Demyelination, and Remyelination in Mouse Brain and Spinal Cord. Methods Mol Biol 2019; 1936:169-183. [PMID: 30820899 DOI: 10.1007/978-1-4939-9072-6_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In vitro culture systems have been invaluable in understanding the cell biology of oligodendrocytes; the monoculture of primary oligodendroglia has helped characterize different stages of oligodendrocyte maturation in the absence of neurons. However, oligodendrocyte monocultures do not model the interaction of oligodendrocytes with neurons where they form myelin wraps. To circumvent this problem, coculture systems were developed; oligodendrocytes and neurons are cultured together, facilitating the study of myelin wraps and the interaction between the two cell types. However, this coculture system also has limitations, as other cells are not present and it does not represent the three-dimensional multicellular structure seen in vivo. Some of these limitations are resolved by using ex vivo slice cultures to serve as a three-dimensional culture system that is more similar to in vivo and can be used to study myelination, demyelination, and remyelination, over extended periods of time. Slice cultures are economical compared to in vivo studies and live imaging using them is less challenging. The focus of this chapter is to describe how to culture brain and spinal cord slices of mice and use them to study myelination, demyelination, and remyelination.
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Affiliation(s)
- Sowmya Sekizar
- MRC Centre for Regenerative Medicine and MS Society Edinburgh Centre, Edinburgh bioQuarter, The University of Edinburgh, Edinburgh, UK
| | - Anna Williams
- MRC Centre for Regenerative Medicine and MS Society Edinburgh Centre, Edinburgh bioQuarter, The University of Edinburgh, Edinburgh, UK.
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7
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Guo YE, Suo N, Cui X, Yuan Q, Xie X. Vitamin C promotes oligodendrocytes generation and remyelination. Glia 2018; 66:1302-1316. [PMID: 29423921 PMCID: PMC6001564 DOI: 10.1002/glia.23306] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 01/22/2018] [Accepted: 01/29/2018] [Indexed: 12/19/2022]
Abstract
Oligodendrocyte‐formed myelin sheaths play important roles in the neuronal functions in the central nervous system. In demyelinating diseases, such as Multiple Sclerosis, the myelin sheaths are damaged and the remyelinating process is somehow hindered. Restoration of the myelin sheaths requires the differentiation of the oligodendrocyte precursor cells (OPCs) into mature oligodendrocytes (OLs). To discover small molecule compounds that might promote the OPC to OL differentiation, a high‐throughput screening system is established and L‐ascorbyl‐2‐phosphate (As‐2P), a stable form of Vitamin C (Vc), is found to greatly enhance the OPC to OL differentiation. As‐2P promotes gradual expression of OL lineage markers, including O4, CNPase and MBP, in a dose‐ and time‐dependent manner. It also facilitates the formation of myelin sheaths in OPC‐neuron co‐culture. As‐2P also promotes the repair of the myelin sheaths in vivo and provides significant therapeutic effect in a cuprizone‐mediated demyelination animal model. Interestingly, As‐2P's function in promoting OPC differentiation is not related to its antioxidant activity. And an intracellular rather than an extracellular mechanism might be involved. Considering the safe use of Vc as a dietary supplement for many years, it might also be used as an alternative medicine for CNS demyelinating diseases.
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Affiliation(s)
- Yu-E Guo
- CAS Key Laboratory of Receptor Research, the National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, Graduate School, No. 19A Yuquan Road, Beijing, 100049, China
| | - Na Suo
- CAS Key Laboratory of Receptor Research, the National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, Graduate School, No. 19A Yuquan Road, Beijing, 100049, China
| | - Xue Cui
- Shanghai Key Laboratory of Signaling and Disease Research, Laboratory of Receptor-based Bio-medicine, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Qianting Yuan
- CAS Key Laboratory of Receptor Research, the National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Xin Xie
- CAS Key Laboratory of Receptor Research, the National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,Shanghai Key Laboratory of Signaling and Disease Research, Laboratory of Receptor-based Bio-medicine, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
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8
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Reassembly of Excitable Domains after CNS Axon Regeneration. J Neurosci 2017; 36:9148-60. [PMID: 27581456 DOI: 10.1523/jneurosci.1747-16.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/15/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Action potential initiation and propagation in myelinated axons require ion channel clustering at axon initial segments (AIS) and nodes of Ranvier. Disruption of these domains after injury impairs nervous system function. Traditionally, injured CNS axons are considered refractory to regeneration, but some recent approaches challenge this view by showing robust long-distance regeneration. However, whether these approaches allow remyelination and promote the reestablishment of AIS and nodes of Ranvier is unknown. Using mouse optic nerve crush as a model for CNS traumatic injury, we performed a detailed analysis of AIS and node disruption after nerve crush. We found significant disruption of AIS and loss of nodes within days of the crush, and complete loss of nodes 1 week after injury. Genetic deletion of the tumor suppressor phosphatase and tensin homolog (Pten) in retinal ganglion cells (RGCs), coupled with stimulation of RGCs by inflammation and cAMP, dramatically enhanced regeneration. With this treatment, we found significant reestablishment of RGC AIS, remyelination, and even reassembly of nodes in regions proximal, within, and distal to the crush site. Remyelination began near the retina, progressed distally, and was confirmed by electron microscopy. Although axons grew rapidly, remyelination and nodal ion channel clustering was much slower. Finally, genetic deletion of ankyrinG from RGCs to block AIS reassembly did not affect axon regeneration, indicating that preservation of neuronal polarity is not required for axon regeneration. Together, our results demonstrate, for the first time, that regenerating CNS axons can be remyelinated and reassemble new AIS and nodes of Ranvier. SIGNIFICANCE STATEMENT We show, for the first time, that regenerated CNS axons have the capacity to both remyelinate and reassemble the axon initial segments and nodes of Ranvier necessary for rapid and efficient action potential propagation.
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9
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Ishii T, Kawakami E, Endo K, Misawa H, Watabe K. Myelinating cocultures of rodent stem cell line-derived neurons and immortalized Schwann cells. Neuropathology 2017; 37:475-481. [PMID: 28707715 DOI: 10.1111/neup.12397] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 06/09/2017] [Accepted: 06/09/2017] [Indexed: 12/26/2022]
Abstract
Myelination is one of the most remarkable biological events in the neuron-glia interactions for the development of the mammalian nervous system. To elucidate molecular mechanisms of cell-to-cell interactions in myelin synthesis in vitro, establishment of the myelinating system in cocultures of continuous neuronal and glial cell lines are desirable. In the present study, we performed co-culture experiments using rat neural stem cell-derived neurons or mouse embryonic stem (ES) cell-derived motoneurons with immortalized rat IFRS1 Schwann cells to establish myelinating cultures between these cell lines. Differentiated neurons derived from an adult rat neural stem cell line 1464R or motoneurons derived from a mouse ES cell line NCH4.3, were mixed with IFRS1 Schwann cells, plated, and maintained in serum-free F12 medium with B27 supplement, ascorbic acid, and glial cell line-derived neurotrophic factor. Myelin formation was demonstrated by electron microscopy at 4 weeks in cocultures of 1464R-derived neurons or NCH4.3-derived motoneurons with IFRS1 Schwann cells. These in vitro coculture systems utilizing the rodent stable stem and Schwann cell lines can be useful in studies of peripheral nerve development and regeneration.
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Affiliation(s)
- Tomohiro Ishii
- Laboratory for Neurodegenerative Pathology, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo, Japan.,Department of Pharmacology, Keio University Faculty of Pharmacy, Minato, Tokyo, Japan
| | - Emiko Kawakami
- Laboratory for Neurodegenerative Pathology, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo, Japan
| | - Kentaro Endo
- Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo, Japan
| | - Hidemi Misawa
- Department of Pharmacology, Keio University Faculty of Pharmacy, Minato, Tokyo, Japan
| | - Kazuhiko Watabe
- Laboratory for Neurodegenerative Pathology, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo, Japan.,Department of Medical Technology (Neuropathology), Kyorin University Faculty of Health Sciences, Mitaka, Tokyo, Japan
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10
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Zou Y, Zhang WF, Liu HY, Li X, Zhang X, Ma XF, Sun Y, Jiang SY, Ma QH, Xu DE. Structure and function of the contactin-associated protein family in myelinated axons and their relationship with nerve diseases. Neural Regen Res 2017; 12:1551-1558. [PMID: 29090003 PMCID: PMC5649478 DOI: 10.4103/1673-5374.215268] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The contactin-associated protein (Caspr) family participates in nerve excitation and conduction, and neurotransmitter release in myelinated axons. We analyzed the structures and functions of the Caspr family–CNTNAP1 (Caspr1), CNTNAP2 (Caspr2), CNTNAP3 (Caspr3), CNTNAP4 (Caspr4) and CNTNAP5 (Caspr5), Caspr1–5 is not only involved in the formation of myelinated axons, but also participates in maintaining the stability of adjacent connections. Caspr1 participates in the formation, differentiation, and proliferation of neurons and astrocytes, and in motor control and cognitive function. We also analyzed the relationship between the Caspr family and neurodegenerative diseases, multiple sclerosis, and autoimmune encephalitis. However, the effects of Caspr on disease course and prognosis remain poorly understood. The effects of Caspr on disease diagnosis and treatment need further investigation.
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Affiliation(s)
- Yan Zou
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Wei-Feng Zhang
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Hai-Ying Liu
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Xia Li
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Xing Zhang
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Xiao-Fang Ma
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Yang Sun
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Shi-Yi Jiang
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Quan-Hong Ma
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - De-En Xu
- Department of Neurology, The Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
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11
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Redmond SA, Mei F, Eshed-Eisenbach Y, Osso LA, Leshkowitz D, Shen YAA, Kay JN, Aurrand-Lions M, Lyons DA, Peles E, Chan JR. Somatodendritic Expression of JAM2 Inhibits Oligodendrocyte Myelination. Neuron 2016; 91:824-836. [PMID: 27499083 DOI: 10.1016/j.neuron.2016.07.021] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/08/2016] [Accepted: 07/01/2016] [Indexed: 02/05/2023]
Abstract
Myelination occurs selectively around neuronal axons to increase the efficiency and velocity of action potentials. While oligodendrocytes are capable of myelinating permissive structures in the absence of molecular cues, structurally permissive neuronal somata and dendrites remain unmyelinated. Utilizing a purified spinal cord neuron-oligodendrocyte myelinating co-culture system, we demonstrate that disruption of dynamic neuron-oligodendrocyte signaling by chemical cross-linking results in aberrant myelination of the somatodendritic compartment of neurons. We hypothesize that an inhibitory somatodendritic cue is necessary to prevent non-axonal myelination. Using next-generation sequencing and candidate profiling, we identify neuronal junction adhesion molecule 2 (JAM2) as an inhibitory myelin-guidance molecule. Taken together, our results demonstrate that the somatodendritic compartment directly inhibits myelination and suggest a model in which broadly indiscriminate myelination is tailored by inhibitory signaling to meet local myelination requirements.
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Affiliation(s)
- Stephanie A Redmond
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Feng Mei
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Lindsay A Osso
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Dena Leshkowitz
- Bioinformatics Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yun-An A Shen
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeremy N Kay
- Departments of Neurobiology and Ophthalmology, Duke University School of Medicine, Durham, NC 27703, USA
| | - Michel Aurrand-Lions
- Centre de Recherche en Cancérologie de Marseille, Inserm, CNRS, Aix-Marseille University, UMR1068, 13284 Marseille, France
| | - David A Lyons
- Centre for Neuroregeneration, Centre for Multiple Sclerosis Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Jonah R Chan
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA.
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12
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G protein-coupled receptor 37 is a negative regulator of oligodendrocyte differentiation and myelination. Nat Commun 2016; 7:10884. [PMID: 26961174 PMCID: PMC4792952 DOI: 10.1038/ncomms10884] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 01/29/2016] [Indexed: 12/22/2022] Open
Abstract
While the formation of myelin by oligodendrocytes is critical for the function of the
central nervous system, the molecular mechanism controlling oligodendrocyte
differentiation remains largely unknown. Here we identify G protein-coupled receptor
37 (GPR37) as an inhibitor of late-stage oligodendrocyte differentiation and
myelination. GPR37 is enriched in oligodendrocytes and its expression increases
during their differentiation into myelin forming cells. Genetic deletion of
Gpr37 does not affect the number of oligodendrocyte precursor cells, but
results in precocious oligodendrocyte differentiation and hypermyelination. The
inhibition of oligodendrocyte differentiation by GPR37 is mediated by suppression of
an exchange protein activated by cAMP (EPAC)-dependent activation of Raf-MAPK-ERK1/2
module and nuclear translocation of ERK1/2. Our data suggest that GPR37 regulates
central nervous system myelination by controlling the transition from
early-differentiated to mature oligodendrocytes. The molecular mechanism controlling oligodendrocyte differentiation is
not fully understood. Here the authors show that G protein coupled receptor 37 acts as a
negative regulator of CNS myelination, and this effect is mediated by suppression of ERK
signalling.
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13
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Kerman BE, Kim HJ, Padmanabhan K, Mei A, Georges S, Joens MS, Fitzpatrick JAJ, Jappelli R, Chandross KJ, August P, Gage FH. In vitro myelin formation using embryonic stem cells. Development 2015; 142:2213-25. [PMID: 26015546 DOI: 10.1242/dev.116517] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 04/21/2015] [Indexed: 01/21/2023]
Abstract
Myelination in the central nervous system is the process by which oligodendrocytes form myelin sheaths around the axons of neurons. Myelination enables neurons to transmit information more quickly and more efficiently and allows for more complex brain functions; yet, remarkably, the underlying mechanism by which myelination occurs is still not fully understood. A reliable in vitro assay is essential to dissect oligodendrocyte and myelin biology. Hence, we developed a protocol to generate myelinating oligodendrocytes from mouse embryonic stem cells and established a myelin formation assay with embryonic stem cell-derived neurons in microfluidic devices. Myelin formation was quantified using a custom semi-automated method that is suitable for larger scale analysis. Finally, early myelination was followed in real time over several days and the results have led us to propose a new model for myelin formation.
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Affiliation(s)
- Bilal E Kerman
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Hyung Joon Kim
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Krishnan Padmanabhan
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA Computational Neuroscience Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA Crick Jacobs Center for Theoretical and Computational Biology, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Arianna Mei
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Shereen Georges
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Matthew S Joens
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - James A J Fitzpatrick
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Roberto Jappelli
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Karen J Chandross
- Sanofi US, R&D, Genzyme MS/Neurology, 55 Corporate Drive, Bridgewater, NJ 08807, USA
| | - Paul August
- Sanofi US, R&D, Early to Candidate Unit, Tucson Innovation Center, 2090 E. Innovation Park Drive, Tucson, AZ 85755, USA
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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14
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Jarjour AA, Boyd A, Dow LE, Holloway RK, Goebbels S, Humbert PO, Williams A, ffrench-Constant C. The polarity protein Scribble regulates myelination and remyelination in the central nervous system. PLoS Biol 2015; 13:e1002107. [PMID: 25807062 PMCID: PMC4373955 DOI: 10.1371/journal.pbio.1002107] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/12/2015] [Indexed: 01/05/2023] Open
Abstract
The development and regeneration of myelin by oligodendrocytes, the myelin-forming cells of the central nervous system (CNS), requires profound changes in cell shape that lead to myelin sheath initiation and formation. Here, we demonstrate a requirement for the basal polarity complex protein Scribble in CNS myelination and remyelination. Scribble is expressed throughout oligodendroglial development and is up-regulated in mature oligodendrocytes where it is localised to both developing and mature CNS myelin sheaths. Knockdown of Scribble expression in cultured oligodendroglia results in disrupted morphology and myelination initiation. When Scribble expression is conditionally eliminated in the myelinating glia of transgenic mice, myelin initiation in CNS is disrupted, both during development and following focal demyelination, and longitudinal extension of the myelin sheath is disrupted. At later stages of myelination, Scribble acts to negatively regulate myelin thickness whilst suppressing the extracellular signal-related kinase (ERK)/mitogen-activated protein kinase (MAP) kinase pathway, and localises to non-compact myelin flanking the node of Ranvier where it is required for paranodal axo-glial adhesion. These findings demonstrate an essential role for the evolutionarily-conserved regulators of intracellular polarity in myelination and remyelination. The polarity protein Scribble regulates the formation and properties of myelin sheaths in the central nervous system during development and after demyelinating injury. The formation of myelin, a fatty, multilayered structure that surrounds certain neuronal axons in the nervous system, is essential for the proper communication of electrical signals by neurons, acting both as an insulator and to promote metabolic support to the axon. Loss of myelin can have severe functional consequences and trigger serious diseases, such as multiple sclerosis. Bidirectional communication between the oligodendrocytes, the myelinating cells of the central nervous system, and the axon is essential for the proper formation and function of myelin membranes; however, the signals that control myelination by oligodendrocytes in the central nervous system are poorly understood. In this paper, we use a combination of cell culture and animal studies to demonstrate that the protein Scribble, which is known to be a highly evolutionarily conserved regulator of cell polarity, plays a role in controlling whether oligodendrocytes myelinate axons. We show that Scribble regulates the length and thickness of myelin sheaths formed, as well as the tight adhesion of oligodendroglial membranes to the axonal surface, which is required for the organization of the axon into specialized domains at the nodes of Ranvier (gaps formed between the myelin sheaths generated by different cells). In addition, we show that Scribble plays a key role in the repair of myelin sheaths in a mouse model of demyelinating disease. The discovery of novel regulators of myelination in the central nervous system may allow for the identification of novel therapeutic targets for the promotion of myelin repair in patients suffering from demyelinating diseases.
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Affiliation(s)
- Andrew A. Jarjour
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Amanda Boyd
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Lukas E. Dow
- Cell Cycle and Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Australia
| | - Rebecca K. Holloway
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Sandra Goebbels
- Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Patrick O. Humbert
- Cell Cycle and Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Pathology, University of Melbourne, Parkville, Victoria, Australia
| | - Anna Williams
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Charles ffrench-Constant
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
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15
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Chang KJ, Zollinger DR, Susuki K, Sherman DL, Makara MA, Brophy PJ, Cooper EC, Bennett V, Mohler PJ, Rasband MN. Glial ankyrins facilitate paranodal axoglial junction assembly. Nat Neurosci 2014; 17:1673-81. [PMID: 25362471 PMCID: PMC4260775 DOI: 10.1038/nn.3858] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 10/08/2014] [Indexed: 02/07/2023]
Abstract
Neuron-glia interactions establish functional membrane domains along myelinated axons. These include nodes of Ranvier, paranodal axoglial junctions and juxtaparanodes. Paranodal junctions are the largest vertebrate junctional adhesion complex, and they are essential for rapid saltatory conduction and contribute to assembly and maintenance of nodes. However, the molecular mechanisms underlying paranodal junction assembly are poorly understood. Ankyrins are cytoskeletal scaffolds traditionally associated with Na(+) channel clustering in neurons and are important for membrane domain establishment and maintenance in many cell types. Here we show that ankyrin-B, expressed by Schwann cells, and ankyrin-G, expressed by oligodendrocytes, are highly enriched at the glial side of paranodal junctions where they interact with the essential glial junctional component neurofascin 155. Conditional knockout of ankyrins in oligodendrocytes disrupts paranodal junction assembly and delays nerve conduction during early development in mice. Thus, glial ankyrins function as major scaffolds that facilitate early and efficient paranodal junction assembly in the developing CNS.
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Affiliation(s)
- Kae-Jiun Chang
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniel R. Zollinger
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Keiichiro Susuki
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Diane L. Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom EH16 4SB
| | - Michael A. Makara
- Departments of Physiology and Cell Biology, Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Peter J. Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom EH16 4SB
| | - Edward C. Cooper
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vann Bennett
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Peter J. Mohler
- Departments of Physiology and Cell Biology, Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew N. Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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16
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Yuen TJ, Johnson KR, Miron VE, Zhao C, Quandt J, Harrisingh MC, Swire M, Williams A, McFarland HF, Franklin RJM, ffrench-Constant C. Identification of endothelin 2 as an inflammatory factor that promotes central nervous system remyelination. Brain 2013; 136:1035-47. [PMID: 23518706 PMCID: PMC3613712 DOI: 10.1093/brain/awt024] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 12/11/2012] [Accepted: 12/21/2012] [Indexed: 11/12/2022] Open
Abstract
The development of new regenerative therapies for multiple sclerosis is hindered by the lack of potential targets for enhancing remyelination. The study of naturally regenerative processes such as the innate immune response represents a powerful approach for target discovery to solve this problem. By 'mining' these processes using transcriptional profiling we can identify candidate factors that can then be tested individually in clinically-relevant models of demyelination and remyelination. Here, therefore, we have examined a previously described in vivo model of the innate immune response in which zymosan-induced macrophage activation in the retina promotes myelin sheath formation by oligodendrocytes generated from transplanted precursor cells. While this model is not itself clinically relevant, it does provide a logical starting point for this study as factors that promote myelination must be present. Microarray analysis of zymosan-treated retinae identified several cytokines (CXCL13, endothelin 2, CCL20 and CXCL2) to be significantly upregulated. When tested in a cerebellar slice culture model, CXCL13 and endothelin 2 promoted myelination and endothelin 2 also promoted remyelination. In studies to identify the receptor responsible for this regenerative effect of endothelin 2, analysis of both remyelination following experimental demyelination and of different stages of multiple sclerosis lesions in human post-mortem tissue revealed high levels of endothelin receptor type B in oligodendrocyte lineage cells. Confirming a role for this receptor in remyelination, small molecule agonists and antagonists of endothelin receptor type B administered in slice cultures promoted and inhibited remyelination, respectively. Antagonists of endothelin receptor type B also inhibited remyelination of experimentally-generated demyelination in vivo. Our work therefore identifies endothelin 2 and the endothelin receptor type B as a regenerative pathway and suggests that endothelin receptor type B agonists represent a promising therapeutic approach to promote myelin regeneration.
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Affiliation(s)
- Tracy J. Yuen
- 1 MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, University of Edinburgh, Edinburgh, UK
- 2 Wellcome Trust MRC Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
- 3 Neuroimmunology Branch, National Institutes of Health, Bethesda, MD, USA
| | - Kory R. Johnson
- 4 Bioinformatics Section, Information Technology and Bioinformatics Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Veronique E. Miron
- 1 MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, University of Edinburgh, Edinburgh, UK
| | - Chao Zhao
- 2 Wellcome Trust MRC Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Jacqueline Quandt
- 3 Neuroimmunology Branch, National Institutes of Health, Bethesda, MD, USA
| | - Marie C. Harrisingh
- 1 MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, University of Edinburgh, Edinburgh, UK
| | - Matthew Swire
- 1 MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, University of Edinburgh, Edinburgh, UK
| | - Anna Williams
- 1 MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, University of Edinburgh, Edinburgh, UK
| | - Henry F. McFarland
- 3 Neuroimmunology Branch, National Institutes of Health, Bethesda, MD, USA
| | - Robin J. M. Franklin
- 2 Wellcome Trust MRC Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Charles ffrench-Constant
- 1 MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, University of Edinburgh, Edinburgh, UK
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17
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Zoupi L, Savvaki M, Karagogeos D. Axons and myelinating glia: An intimate contact. IUBMB Life 2011; 63:730-5. [PMID: 21793162 DOI: 10.1002/iub.513] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Accepted: 04/18/2011] [Indexed: 01/06/2023]
Abstract
The coordination of the vertebrate nervous system requires high velocity signal transmission between different brain areas. High speed nerve conduction is achieved in the myelinated fibers of both the central and the peripheral nervous system where the myelin sheath acts as an insulator of the axon. The interactions between the glial cell and the adjacent axon, namely axo-glial interactions, segregate the fiber in distinct molecular and functional domains that ensure the rapid propagation of action potentials. These domains are the node of Ranvier, the paranode, the juxtaparanode and the internode and are characterized by multiprotein complexes between voltage-gated ion channels, cell adhesion molecules, members of the Neurexin family and cytoskeletal proteins. In the present review, we outline recent evidence on the key players of axo-glial interactions, depicting their importance in myelinated fiber physiology and disease.
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Affiliation(s)
- Lida Zoupi
- Department of Basic Science, Faculty of Medicine, University of Crete, Institute of Molecular Biology & Biotechnology-FoRTH, Heraklion, Greece
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18
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Novak N, Bar V, Sabanay H, Frechter S, Jaegle M, Snapper SB, Meijer D, Peles E. N-WASP is required for membrane wrapping and myelination by Schwann cells. ACTA ACUST UNITED AC 2011; 192:243-50. [PMID: 21263026 PMCID: PMC3172181 DOI: 10.1083/jcb.201010013] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
N-WASP–deficient Schwann cells sort and ensheath axons but arrest at the promyelinating stage. During peripheral nerve myelination, Schwann cells sort larger axons, ensheath them, and eventually wrap their membrane to form the myelin sheath. These processes involve extensive changes in cell shape, but the exact mechanisms involved are still unknown. Neural Wiskott–Aldrich syndrome protein (N-WASP) integrates various extracellular signals to control actin dynamics and cytoskeletal reorganization through activation of the Arp2/3 complex. By generating mice lacking N-WASP in myelinating Schwann cells, we show that N-WASP is crucial for myelination. In N-WASP–deficient nerves, Schwann cells sort and ensheath axons, but most of them fail to myelinate and arrest at the promyelinating stage. Yet, a limited number of Schwann cells form unusually short internodes, containing thin myelin sheaths, with the occasional appearance of myelin misfoldings. These data suggest that regulation of actin filament nucleation in Schwann cells by N-WASP is crucial for membrane wrapping, longitudinal extension, and myelination.
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Affiliation(s)
- Nurit Novak
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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19
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Response of human oligodendrocyte progenitors to growth factors and axon signals. J Neuropathol Exp Neurol 2010; 69:930-44. [PMID: 20720504 DOI: 10.1097/nen.0b013e3181ef3be4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
We examined the effects of growth factors and axonal signals on the differentiation of human fetal and adult oligodendrocyte progenitor cells (OPCs) and determined whether these effects translated into enhanced axonal ensheathment. Only small numbers of fetal OPCs grown in defined medium expressed the oligodendroglial lineage markers Olig2 and O4. The combination of platelet-derived growth factor-AA and basic fibroblast growth factor enhanced proliferation of Olig2-positive and O4-positive cells; a combination of brain-derived neurotrophic factor and insulin-like growth factor 1 promoted O4-positive cell differentiation, galactocerebroside expression, and morphological complexity. Coculturing with rodent dorsal root ganglion neurons in defined medium alone enhanced OPC differentiation and myelin basic protein expression. The addition of brain-derived neurotrophic factor/insulin-like growth factor 1 further enhanced differentiation, axonal attachment and ensheathment, and clustering of the contactin-associated protein Caspr and Na+ channels. By contrast, most adult OPCs were O4 positive and Olig2 positive in defined medium; both brain-derived neurotrophic factor/insulin-like growth factor 1 and platelet-derived growth factor-AA/basic fibroblast growth factor promoted their myelin basic protein expression and membrane sheet formation; coculture with dorsal root ganglion neurons further increased myelin basic protein expression. Growth factors also enhanced attachment of adult OPCs to axons, but their capacity to ensheath axons was lower than that of fetal OPCs. These results demonstrate that fetal and adult OPCs show measurable responses to selected growth factors and axon signals that correlate with their capacity for axon ensheathment. The distinct properties of fetal and adult OPCs may be related to differences in their chronological age and initial differentiation states.
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20
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Piaton G, Gould RM, Lubetzki C. Axon-oligodendrocyte interactions during developmental myelination, demyelination and repair. J Neurochem 2010; 114:1243-60. [PMID: 20524961 DOI: 10.1111/j.1471-4159.2010.06831.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In multiple sclerosis, CNS demyelination is often followed by spontaneous repair, mostly achieved by adult oligodendrocyte precursor cells. Extent of this myelin repair differs, ranging from very low, limited to the plaque border, to extensive, with remyelination throughout the 'shadow plaques.' In addition to restoring neuronal connectivity, new myelin is neuroprotective. It reduces axonal loss and thus disability progression. Reciprocal communication between neurons and oligodendrocytes is essential for both myelin biogenesis and myelin repair. Hence, deciphering neuron-oligodendrocyte communication is not only important for understanding myelination per se, but also the pathophysiology that underlies demyelinating diseases and the development of innovative therapeutic strategies.
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