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Numata-Uematasu Y, Wakatsuki S, Kobayashi-Ujiie Y, Sakai K, Ichinohe N, Araki T. In vitro myelination using explant culture of dorsal root ganglia: An efficient tool for analyzing peripheral nerve differentiation and disease modeling. PLoS One 2023; 18:e0285897. [PMID: 37224113 DOI: 10.1371/journal.pone.0285897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 05/03/2023] [Indexed: 05/26/2023] Open
Abstract
Peripheral nerves conducting motor and somatosensory signals in vertebrate consist of myelinated and unmyelinated axons. In vitro myelination culture, generated by co-culturing Schwann cells (SCs) and dorsal root ganglion (DRG) neurons, is an indispensable tool for modeling physiological and pathological conditions of the peripheral nervous system (PNS). This technique allows researchers to overexpress or downregulate molecules investigated in neurons or SCs to evaluate the effect of such molecules on myelination. In vitro myelination experiments are usually time-consuming and labor-intensive to perform. Here we report an optimized protocol for in vitro myelination using DRG explant culture. We found that our in vitro myelination using DRG explant (IVMDE) culture not only achieves myelination with higher efficiency than conventional in vitro myelination methods, but also can be used to observe Remak bundle and non-myelinating SCs, which were unrecognizable in conventional methods. Because of these characteristics, IVMDE may be useful in modeling PNS diseases, including Charcot Marie Tooth disease (CMT), in vitro. These results suggest that IVMDE may achieve a condition more similar to peripheral nerve myelination observed during physiological development.
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Affiliation(s)
- Yurika Numata-Uematasu
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Shuji Wakatsuki
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yuka Kobayashi-Ujiie
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Kazuhisa Sakai
- Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Noritaka Ichinohe
- Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Toshiyuki Araki
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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Hong YB, Joo J, Hyun YS, Kwak G, Choi YR, Yeo HK, Jwa DH, Kim EJ, Mo WM, Nam SH, Kim SM, Yoo JH, Koo H, Park HT, Chung KW, Choi BO. A Mutation in PMP2 Causes Dominant Demyelinating Charcot-Marie-Tooth Neuropathy. PLoS Genet 2016; 12:e1005829. [PMID: 26828946 PMCID: PMC4735456 DOI: 10.1371/journal.pgen.1005829] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/05/2016] [Indexed: 01/05/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of peripheral neuropathies with diverse genetic causes. In this study, we identified p.I43N mutation in PMP2 from a family exhibiting autosomal dominant demyelinating CMT neuropathy by whole exome sequencing and characterized the clinical features. The age at onset was the first to second decades and muscle atrophy started in the distal portion of the leg. Predominant fatty replacement in the anterior and lateral compartment was similar to that in CMT1A caused by PMP22 duplication. Sural nerve biopsy showed onion bulbs and degenerating fibers with various myelin abnormalities. The relevance of PMP2 mutation as a genetic cause of dominant CMT1 was assessed using transgenic mouse models. Transgenic mice expressing wild type or mutant (p.I43N) PMP2 exhibited abnormal motor function. Electrophysiological data revealed that both mice had reduced motor nerve conduction velocities (MNCV). Electron microscopy revealed that demyelinating fibers and internodal lengths were shortened in both transgenic mice. These data imply that overexpression of wild type as well as mutant PMP2 also causes the CMT1 phenotype, which has been documented in the PMP22. This report might expand the genetic and clinical features of CMT and a further mechanism study will enhance our understanding of PMP2-associated peripheral neuropathy. Isolation of causative mutation is still challenging in genetic diseases with a variety of genetic causes. We discovered a mutation in a novel gene from a family exhibiting a peripheral neuropathy by virtue of next-generation sequencing. Although the family shows characteristic clinical features of hereditary motor and sensory neuropathy, we could not find a mutation from well-known genes. To demonstrate the clinical relevance of the novel gene, we generated transgenic mice, which carry the patients’ mutation within their chromosome. The transgenic mice exhibited the same phenotype as the patients including peripheral neuropathic symptoms and reduced locomotor function. We also observed the affected peripheral nervous system through electron microscopy. It seems that the expression of the mutant protein impairs the myelin of peripheral nervous system. These data might expand the genetic, clinical, and pathophysiological features of the peripheral neuropathy and a further investigation will enhance our understanding of disease in the peripheral nervous system.
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Affiliation(s)
- Young Bin Hong
- Stem Cell and Regenerative Medicine Center, Samsung Medical Center, Seoul, Korea
| | - Jaesoon Joo
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
| | - Young Se Hyun
- Department of Biological Science, Kongju National University, Gongju, Korea
| | - Geon Kwak
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Korea
| | - Yu-Ri Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ha Kyung Yeo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Dong Hwan Jwa
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Eun Ja Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
| | - Won Min Mo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Soo Hyun Nam
- Department of Biological Science, Kongju National University, Gongju, Korea
| | - Sung Min Kim
- Department of Biological Science, Kongju National University, Gongju, Korea
| | - Jeong Hyun Yoo
- Department of Radiology, Ewha Womans University, School of Medicine, Seoul, Korea
| | - Heasoo Koo
- Department of Pathology, Ewha Womans University, School of Medicine, Seoul, Korea
| | - Hwan Tae Park
- Department of Physiology, College of Medicine, Dong-A University, Busan, Korea
| | - Ki Wha Chung
- Department of Biological Science, Kongju National University, Gongju, Korea
- * E-mail: (KWC); (BOC)
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
- * E-mail: (KWC); (BOC)
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Su WF, Gu Y, Wei ZY, Shen YT, Jin ZH, Yuan Y, Gu XS, Chen G. Rab27a/Slp2-a complex is involved in Schwann cell myelination. Neural Regen Res 2016; 11:1830-1838. [PMID: 28123429 PMCID: PMC5204241 DOI: 10.4103/1673-5374.194755] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Myelination of Schwann cells in the peripheral nervous system is an intricate process involving myelin protein trafficking. Recently, the role and mechanism of the endosomal/lysosomal system in myelin formation were emphasized. Our previous results demonstrated that a small GTPase Rab27a regulates lysosomal exocytosis and myelin protein trafficking in Schwann cells. In this present study, we established a dorsal root ganglion (DRG) neuron and Schwann cell co-culture model to identify the signals associated with Rab27a during myelination. First, Slp2-a, as the Rab27a effector, was endogenously expressed in Schwann cells. Second, Rab27a expression significantly increased during Schwann cell myelination. Finally, Rab27a and Slp2-a silencing in Schwann cells not only reduced myelin protein expression, but also impaired formation of myelin-like membranes in DRG neuron and Schwann cell co-cultures. Our findings suggest that the Rab27a/Slp2-a complex affects Schwann cell myelination in vitro.
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Affiliation(s)
- Wen-Feng Su
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Yun Gu
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Zhong-Ya Wei
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Yun-Tian Shen
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Zi-Han Jin
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Ying Yuan
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China; Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Xiao-Song Gu
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Gang Chen
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
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Park SJ, Shin EJ, Min SS, An J, Li Z, Hee Chung Y, Hoon Jeong J, Bach JH, Nah SY, Kim WK, Jang CG, Kim YS, Nabeshima YI, Nabeshima T, Kim HC. Inactivation of JAK2/STAT3 signaling axis and downregulation of M1 mAChR cause cognitive impairment in klotho mutant mice, a genetic model of aging. Neuropsychopharmacology 2013; 38:1426-37. [PMID: 23389690 PMCID: PMC3682136 DOI: 10.1038/npp.2013.39] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We previously reported cognitive dysfunction in klotho mutant mice. In the present study, we further examined novel mechanisms involved in cognitive impairment in these mice. Significantly decreased janus kinase 2 (JAK2) and signal transducer and activator of transcription3 (STAT3) phosphorylation were observed in the hippocampus of klotho mutant mice. A selective decrease in protein expression and binding density of the M1 muscarinic cholinergic receptor (M1 mAChR) was observed in these mice. Cholinergic parameters (ie, acetylcholine (ACh), choline acetyltransferase (ChAT), and acetylcholinesterase (AChE)) and NMDAR-dependent long-term potentiation (LTP) were significantly impaired in klotho mutant mice. McN-A-343 (McN), an M1 mAChR agonist, significantly attenuated these impairments. AG490 (AG), a JAK2 inhibitor, counteracted the attenuating effects of McN, although AG did not significantly alter the McN-induced effect on AChE. Furthermore, AG significantly inhibited the attenuating effects of McN on decreased NMDAR-dependent LTP, protein kinase C βII, p-ERK, p-CREB, BDNF, and p-JAK2/p-STAT3-expression in klotho mutant mice. In addition, k252a, a BDNF receptor tyrosine kinase B (TrkB) inhibitor, significantly counteracted McN effects on decreased ChAT, ACh, and M1 mAChR and p-JAK2/p-STAT3 expression. McN-induced effects on cognitive impairment in klotho mutant mice were consistently counteracted by either AG or k252a. Our results suggest that inactivation of the JAK2/STAT3 signaling axis and M1 mAChR downregulation play a critical role in cognitive impairment observed in klotho mutant mice.
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Affiliation(s)
- Seok-Joo Park
- Neuropsychopharmacology and Toxicology Program, Department of Pharmacy, College of Pharmacy, Kangwon National University, Chunchon, South Korea,Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, Department of Pharmacy, College of Pharmacy, Kangwon National University, Chunchon, South Korea
| | - Sun Seek Min
- Department of Physiology and Biophysics, College of Medicine, Eulji University, Daejeon, South Korea,Department of Physiology and Biophysics, College of Medicine, Eulji University, Daejeon 301-746, South Korea, Tel: +82 42 259 1633, Fax: +82 42 259 1639, E-mail:
| | - Jihua An
- Department of Physiology and Biophysics, College of Medicine, Eulji University, Daejeon, South Korea
| | - Zhengyi Li
- Neuropsychopharmacology and Toxicology Program, Department of Pharmacy, College of Pharmacy, Kangwon National University, Chunchon, South Korea
| | - Yoon Hee Chung
- Department of Anatomy, College of Medicine, Chung-Ang University, Seoul, South Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, South Korea
| | - Jae-Hyung Bach
- Neuropsychopharmacology and Toxicology Program, Department of Pharmacy, College of Pharmacy, Kangwon National University, Chunchon, South Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory, Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul, South Korea
| | - Won-Ki Kim
- Department of Neuroscience, College of Medicine, Korea University, Seoul, South Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, South Korea
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Yo-ichi Nabeshima
- Laboratory of Molecular Life Science, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation, Kobe, Japan
| | - Toshitaka Nabeshima
- Department of Regional Pharmaceutical Care and Science, Graduate School of Pharmaceutical Sciences, Meijo University, Nagoya, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, Department of Pharmacy, College of Pharmacy, Kangwon National University, Chunchon, South Korea,Neuropsychopharmacology and Toxicology Program, Department of Pharmacy, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea, Tel: +82 33 250 6917, Fax: +82 33 255 7865, E-mail:
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Li J, Parker B, Martyn C, Natarajan C, Guo J. The PMP22 gene and its related diseases. Mol Neurobiol 2012; 47:673-98. [PMID: 23224996 DOI: 10.1007/s12035-012-8370-x] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/22/2012] [Indexed: 10/27/2022]
Abstract
Peripheral myelin protein-22 (PMP22) is primarily expressed in the compact myelin of the peripheral nervous system. Levels of PMP22 have to be tightly regulated since alterations of PMP22 levels by mutations of the PMP22 gene are responsible for >50 % of all patients with inherited peripheral neuropathies, including Charcot-Marie-Tooth type-1A (CMT1A) with trisomy of PMP22, hereditary neuropathy with liability to pressure palsies (HNPP) with heterozygous deletion of PMP22, and CMT1E with point mutations of PMP22. While overexpression and point-mutations of the PMP22 gene may produce gain-of-function phenotypes, deletion of PMP22 results in a loss-of-function phenotype that reveals the normal physiological functions of the PMP22 protein. In this article, we will review the basic genetics, biochemistry and molecular structure of PMP22, followed by discussion of the current understanding of pathogenic mechanisms involving in the inherited neuropathies with mutations in PMP22 gene.
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Affiliation(s)
- Jun Li
- VA Tennessee Valley Healthcare System, 1310 24th Avenue South, Nashville, TN 37212, USA.
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Callizot N, Combes M, Steinschneider R, Poindron P. A new long term in vitro model of myelination. Exp Cell Res 2011; 317:2374-83. [PMID: 21777582 DOI: 10.1016/j.yexcr.2011.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/30/2011] [Accepted: 07/03/2011] [Indexed: 11/19/2022]
Abstract
Besides in vivo models, co-cultures systems making use of Rat dorsal root ganglion explants/Schwann cells (SC) are widely used to essentially study myelination in vitro. In the case of animal models of demyelinating diseases, it is expected to reproduce a pathological process; conversely the co-cultures are primarily developed to study the myelination process and in the aim to use them to replace animals in experiences of myelin destruction or functional disturbances. We describe (in terms of protein expression kinetic) a new in vitro model of sensory neurons/SC co-cultures presenting the following advantages: both sensory neurons and SC originate from the same individual; sensory neurons and SC being dissociated, they can be co-cultured in monolayer, allowing an easier microscope observation; the co-culture can be maintained in a serum-free medium for at less three months, allowing kinetic studies of myelin formation both at a molecular and cellular level. Optimizing culture conditions permits to use 96-well culture plates; image analyses conducted with an automatic image analyzer allows rapid, accurate and quantitative expression of results. Finally, this system was proved by measuring the apparition of myelin protein to mimic in vitro the physiological process of in vivo myelination.
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Affiliation(s)
- Noelle Callizot
- Neuron Experts SAS, Faculté de Médecine Nord, 51 Boulevard Pierre Dramard, Marseille Cedex 20, France.
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Saporta MA, Katona I, Lewis RA, Masse S, Shy ME, Li J. Shortened internodal length of dermal myelinated nerve fibres in Charcot-Marie-Tooth disease type 1A. Brain 2010; 132:3263-73. [PMID: 19923170 DOI: 10.1093/brain/awp274] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Charcot-Marie-Tooth disease type 1A is the most common inherited neuropathy and is caused by duplication of chromosome 17p11.2 containing the peripheral myelin protein-22 gene. This disease is characterized by uniform slowing of conduction velocities and secondary axonal loss, which are in contrast with non-uniform slowing of conduction velocities in acquired demyelinating disorders, such as chronic inflammatory demyelinating polyradiculoneuropathy. Mechanisms responsible for the slowed conduction velocities and axonal loss in Charcot-Marie-Tooth disease type 1A are poorly understood, in part because of the difficulty in obtaining nerve samples from patients, due to the invasive nature of nerve biopsies. We have utilized glabrous skin biopsies, a minimally invasive procedure, to evaluate these issues systematically in patients with Charcot-Marie-Tooth disease type 1A (n = 32), chronic inflammatory demyelinating polyradiculoneuropathy (n = 4) and healthy controls (n = 12). Morphology and molecular architecture of dermal myelinated nerve fibres were examined using immunohistochemistry and electron microscopy. Internodal length was uniformly shortened in patients with Charcot-Marie-Tooth disease type 1A, compared with those in normal controls (P < 0.0001). Segmental demyelination was absent in the Charcot-Marie-Tooth disease type 1A group, but identifiable in all patients with chronic inflammatory demyelinating polyradiculoneuropathy. Axonal loss was measurable using the density of Meissner corpuscles and associated with an accumulation of intra-axonal mitochondria. Our study demonstrates that skin biopsy can reveal pathological and molecular architectural changes that distinguish inherited from acquired demyelinating neuropathies. Uniformly shortened internodal length in Charcot-Marie-Tooth disease type 1A suggests a potential developmental defect of internodal lengthening. Intra-axonal accumulation of mitochondria provides new insights into the pathogenesis of axonal degeneration in Charcot-Marie-Tooth disease type 1A.
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Affiliation(s)
- Mario A Saporta
- Department of Neurology, Wayne State University, Detroit 48201, USA
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Päiväläinen S, Nissinen M, Honkanen H, Lahti O, Kangas SM, Peltonen J, Peltonen S, Heape AM. Myelination in mouse dorsal root ganglion/Schwann cell cocultures. Mol Cell Neurosci 2007; 37:568-78. [PMID: 18206387 DOI: 10.1016/j.mcn.2007.12.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 11/26/2007] [Accepted: 12/06/2007] [Indexed: 10/22/2022] Open
Abstract
The established protocols for in vitro studies of peripheral nerve myelination with rat embryonic dorsal root ganglia (DRG) and postnatal Schwann cell cocultures do not work with mouse cells. Consequently, the full potential of this model, which would allow to perform cell type-specific, mixed genotype cocultures without cross-breeding the animals, cannot be exploited. We determined the conditions required to promote full myelination in cocultures of pre-purified mouse embryonic DRG and neonatal Schwann cells, and present a method which consistently yields 50-200 mature myelin sheaths/culture. Causes for the failure of the existing protocols to yield satisfactory results with mouse cells fell into three categories: the lack of adherent support provided by the substratum, growth factor and hormone deficiencies, and the high serum content of the media. For optimal results, mouse cocultures require a 3-dimensional substratum, a myelination-promoting culture medium containing pituitary extract, N2 supplement and forskolin, and a low serum concentration.
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Affiliation(s)
- Satu Päiväläinen
- Department of Anatomy and Cell Biology, University of Oulu, Aapistie 7A, 90014 Oulu, Finland
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Honkanen H, Lahti O, Nissinen M, Myllylä RM, Kangas S, Päiväläinen S, Alanne MH, Peltonen S, Peltonen J, Heape AM. Isolation, purification and expansion of myelination-competent, neonatal mouse Schwann cells. Eur J Neurosci 2007; 26:953-64. [PMID: 17714189 DOI: 10.1111/j.1460-9568.2007.05726.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Most studies of peripheral nerve myelination using culture models are performed with dorsal root ganglion neurons and Schwann cells pre-purified from the rat. The potential of this model is severely compromised by the lack of rat myelin mutants and the published protocols work poorly with mouse cells, for which numerous myelin mutants are available. This is partly due to difficulties in obtaining sufficient quantities of myelination-competent mouse Schwann cells. Here, we describe the isolation, purification and expansion of wild-type, myelination-competent Schwann cells from the sciatic nerves of 4-day-old mouse pups. The method consistently yields 1.9-3.3 x 10(6) of approximately 95% pure Schwann cells from the sciatic nerves of 12-15 4-day-old mouse pups, within 14-20 days. The Schwann cell proliferation rate ranges from 2.7- to 4.30-fold growth/week. Proliferation ceases within 4 weeks, when the cells become quiescent. Growth is reinduced by the presence of neurons; neuregulin is not sufficient for this effect. The Schwann cells isolated by this protocol are able to form compact myelin in culture, as judged by the segregated expression patterns of early (myelin-associated glycoprotein) and late (myelin basic protein) myelination markers in a three-dimensional neuron/Schwann cell coculture model. The Schwann cell batch yields are sufficient to perform 100-150 individual myelinating coculture assays. Employing mixed phenotype/genotype mouse neuron/Schwann cell cocultures, it will be possible to analyse the cell specificity of a mutation, and the cumulative effects of different mutations, without having to cross-breed the animals.
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Affiliation(s)
- Henrika Honkanen
- Department of Anatomy and Cell Biology, University of Oulu, Finland
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Liu N, Varma S, Tsao D, Shooter EM, Tolwani RJ. Depleting endogenous neurotrophin-3 enhances myelin formation in the Trembler-J mouse, a model of a peripheral neuropathy. J Neurosci Res 2007; 85:2863-9. [PMID: 17628499 DOI: 10.1002/jnr.21388] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The heterozygous Trembler-J (TrJ/+) mouse, containing a point mutation in the peripheral myelin protein 22 (Pmp22) gene, is characterized by severe hypomyelination and is a representative model of Charcot-Marie-Tooth 1A (CMT1A) disease/Dejerine-Sottas syndrome (DSS). Given that the neurotrophin-3 (NT3)-TrkC signaling pathway is inhibitory to myelination during development, we investigated the role of the NT3-TrkC pathway in myelination and manipulated this pathway to improve myelin formation in the CMT1A/DSS mouse model. Injection of NT3 to the TrJ/+ mice decreased the myelin protein P(0) level in the sciatic nerves. Suppressing the NT3-TrkC pathway with TrkC-Fc, an NT3 scavenger, enhanced myelination in vitro and in vivo in the TrJ/+ mouse. Furthermore, we found that full-length TrkC was expressed in adult TrJ/+ mouse sciatic nerves but was not detected in the wild-type adults, suggesting that the full-length TrkC is a potential target of treatment to enhance myelination in the TrJ/+ mouse.
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Affiliation(s)
- Ning Liu
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
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