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Jessen KR, Mirsky R. The Success and Failure of the Schwann Cell Response to Nerve Injury. Front Cell Neurosci 2019; 13:33. [PMID: 30804758 PMCID: PMC6378273 DOI: 10.3389/fncel.2019.00033] [Citation(s) in RCA: 272] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 01/22/2019] [Indexed: 01/06/2023] Open
Abstract
The remarkable plasticity of Schwann cells allows them to adopt the Remak (non-myelin) and myelin phenotypes, which are specialized to meet the needs of small and large diameter axons, and differ markedly from each other. It also enables Schwann cells initially to mount a strikingly adaptive response to nerve injury and to promote regeneration by converting to a repair-promoting phenotype. These repair cells activate a sequence of supportive functions that engineer myelin clearance, prevent neuronal death, and help axon growth and guidance. Eventually, this response runs out of steam, however, because in the long run the phenotype of repair cells is unstable and their survival is compromised. The re-programming of Remak and myelin cells to repair cells, together with the injury-induced switch of peripheral neurons to a growth mode, gives peripheral nerves their strong regenerative potential. But it remains a challenge to harness this potential and devise effective treatments that maintain the initial repair capacity of peripheral nerves for the extended periods typically required for nerve repair in humans.
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Affiliation(s)
- Kristjan R Jessen
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Rhona Mirsky
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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Yang S, Li S, Li XJ. Shortening the Half-Life of Cas9 Maintains Its Gene Editing Ability and Reduces Neuronal Toxicity. Cell Rep 2018; 25:2653-2659.e3. [PMID: 30517854 PMCID: PMC6314484 DOI: 10.1016/j.celrep.2018.11.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 09/20/2018] [Accepted: 11/01/2018] [Indexed: 12/22/2022] Open
Abstract
Virus-mediated expression of CRISPR/Cas9 is commonly used for genome editing in animal brains to model or treat neurological diseases, but the potential neurotoxicity of overexpressing bacterial Cas9 in the mammalian brain remains unknown. Through RNA sequencing (RNA-seq) analysis, we find that virus-mediated expression of Cas9 influences the expression of genes involved in neuronal functions. Reducing the half-life of Cas9 by tagging with geminin, whose expression is regulated by the cell cycle, maintains the genome editing capacity of Cas9 but significantly alleviates neurotoxicity. Thus, modification of Cas9 by shortening its half-life can help develop CRISPR/Cas9-based therapeutic approaches for treating neurological disorders.
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Affiliation(s)
- Su Yang
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA.
| | - Shihua Li
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA
| | - Xiao-Jiang Li
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA.
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53
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Ma KH, Duong P, Moran JJ, Junaidi N, Svaren J. Polycomb repression regulates Schwann cell proliferation and axon regeneration after nerve injury. Glia 2018; 66:2487-2502. [PMID: 30306639 PMCID: PMC6289291 DOI: 10.1002/glia.23500] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 07/02/2018] [Accepted: 07/03/2018] [Indexed: 01/01/2023]
Abstract
The transition of differentiated Schwann cells to support of nerve repair after injury is accompanied by remodeling of the Schwann cell epigenome. The EED-containing polycomb repressive complex 2 (PRC2) catalyzes histone H3K27 methylation and represses key nerve repair genes such as Shh, Gdnf, and Bdnf, and their activation is accompanied by loss of H3K27 methylation. Analysis of nerve injury in mice with a Schwann cell-specific loss of EED showed the reversal of polycomb repression is required and a rate limiting step in the increased transcription of Neuregulin 1 (type I), which is required for efficient remyelination. However, mouse nerves with EED-deficient Schwann cells display slow axonal regeneration with significantly low expression of axon guidance genes, including Sema4f and Cntf. Finally, EED loss causes impaired Schwann cell proliferation after injury with significant induction of the Cdkn2a cell cycle inhibitor gene. Interestingly, PRC2 subunits and CDKN2A are commonly co-mutated in the transition from benign neurofibromas to malignant peripheral nerve sheath tumors (MPNST's). RNA-seq analysis of EED-deficient mice identified PRC2-regulated molecular pathways that may contribute to the transition to malignancy in neurofibromatosis.
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Affiliation(s)
- Ki H. Ma
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Phu Duong
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - John J. Moran
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Nabil Junaidi
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - John Svaren
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53705, USA
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54
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Zhang J, Liu Y, Lu L. Emerging role of MicroRNAs in peripheral nerve system. Life Sci 2018; 207:227-233. [PMID: 29894714 DOI: 10.1016/j.lfs.2018.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/21/2018] [Accepted: 06/08/2018] [Indexed: 01/17/2023]
Abstract
Peripheral nerve injury is one of the most common clinical diseases. Although the regeneration of the peripheral nerve is better than that of the nerves of the central nervous system, because of its growth rate restrictions after damage. Hence, the outcome of repair after injury is not favorable. Small RNA, a type of non-coding RNA, has recently been gaining attention in neural injury. It is widely distributed in the nervous system in vivo and a significant change in the expression of small RNAs has been observed in a neural injury model. This suggests that MicroRNAs (miRNAs) may serve as a potential target for resolving the challenges of peripheral nerve repair. This review summarizes the current challenges in peripheral nerve injury repair, systematically expounds the mechanism of miRNAs in the process of nerve injury and repair and attempts to determine the possible treatment of peripheral nerve injury.
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Affiliation(s)
- Jiayi Zhang
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China
| | - Yang Liu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China
| | - Laijin Lu
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China.
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Norrmén C, Figlia G, Pfistner P, Pereira JA, Bachofner S, Suter U. mTORC1 Is Transiently Reactivated in Injured Nerves to Promote c-Jun Elevation and Schwann Cell Dedifferentiation. J Neurosci 2018; 38:4811-4828. [PMID: 29695414 PMCID: PMC5956991 DOI: 10.1523/jneurosci.3619-17.2018] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/14/2018] [Accepted: 04/21/2018] [Indexed: 12/31/2022] Open
Abstract
Schwann cells (SCs) are endowed with a remarkable plasticity. When peripheral nerves are injured, SCs dedifferentiate and acquire new functions to coordinate nerve repair as so-called repair SCs. Subsequently, SCs redifferentiate to remyelinate regenerated axons. Given the similarities between SC dedifferentiation/redifferentiation in injured nerves and in demyelinating neuropathies, elucidating the signals involved in SC plasticity after nerve injury has potentially wider implications. c-Jun has emerged as a key transcription factor regulating SC dedifferentiation and the acquisition of repair SC features. However, the upstream pathways that control c-Jun activity after nerve injury are largely unknown. We report that the mTORC1 pathway is transiently but robustly reactivated in dedifferentiating SCs. By inducible genetic deletion of the functionally crucial mTORC1-subunit Raptor in mouse SCs (including male and female animals), we found that mTORC1 reactivation is necessary for proper myelin clearance, SC dedifferentiation, and consequently remyelination, without major alterations in the inflammatory response. In the absence of mTORC1 signaling, c-Jun failed to be upregulated correctly. Accordingly, a c-Jun binding motif was found to be enriched in promoters of genes with reduced expression in injured mutants. Furthermore, using cultured SCs, we found that mTORC1 is involved in c-Jun regulation by promoting its translation, possibly via the eIF4F-subunit eIF4A. These results provide evidence that proper c-Jun elevation after nerve injury involves also mTORC1-dependent post-transcriptional regulation to ensure timely dedifferentiation of SCs.SIGNIFICANCE STATEMENT A crucial evolutionary acquisition of vertebrates is the envelopment of axons in myelin sheaths produced by oligodendrocytes in the CNS and Schwann cells (SCs) in the PNS. When myelin is damaged, conduction of action potentials along axons slows down or is blocked, leading to debilitating diseases. Unlike oligodendrocytes, SCs have a high regenerative potential, granted by their remarkable plasticity. Thus, understanding the mechanisms underlying SC plasticity may uncover new therapeutic targets in nerve regeneration and demyelinating diseases. Our work reveals that reactivation of the mTORC1 pathway in SCs is essential for efficient SC dedifferentiation after nerve injury. Accordingly, modulating this signaling pathway might be of therapeutic relevance in peripheral nerve injury and other diseases.
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Affiliation(s)
- Camilla Norrmén
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich CH-8093, Switzerland
| | - Gianluca Figlia
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich CH-8093, Switzerland
| | - Patrick Pfistner
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich CH-8093, Switzerland
| | - Jorge A Pereira
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich CH-8093, Switzerland
| | - Sven Bachofner
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich CH-8093, Switzerland
| | - Ueli Suter
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich CH-8093, Switzerland
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Law WD, Fogarty EA, Vester A, Antonellis A. A genome-wide assessment of conserved SNP alleles reveals a panel of regulatory SNPs relevant to the peripheral nerve. BMC Genomics 2018; 19:311. [PMID: 29716548 PMCID: PMC5930951 DOI: 10.1186/s12864-018-4692-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 04/17/2018] [Indexed: 12/29/2022] Open
Abstract
Background Identifying functional non-coding variation is critical for defining the genetic contributions to human disease. While single-nucleotide polymorphisms (SNPs) within cis-acting transcriptional regulatory elements have been implicated in disease pathogenesis, not all cell types have been assessed and functional validations have been limited. In particular, the cells of the peripheral nervous system have been excluded from genome-wide efforts to link non-coding SNPs to altered gene function. Addressing this gap is essential for defining the genetic architecture of diseases that affect the peripheral nerve. We developed a computational pipeline to identify SNPs that affect regulatory function (rSNPs) and evaluated our predictions on a set of 144 regions in Schwann cells, motor neurons, and muscle cells. Results We identified 28 regions that display regulatory activity in at least one cell type and 13 SNPs that affect regulatory function. We then tailored our pipeline to one peripheral nerve cell type by incorporating SOX10 ChIP-Seq data; SOX10 is essential for Schwann cells. We prioritized 22 putative SOX10 response elements harboring a SNP and rapidly validated two rSNPs. We then selected one of these elements for further characterization to assess the biological relevance of our approach. Deletion of the element from the genome of cultured Schwann cells—followed by differential gene expression studies—revealed Tubb2b as a candidate target gene. Studying the enhancer in developing mouse embryos revealed activity in SOX10-positive cells including the dorsal root ganglia and melanoblasts. Conclusions Our efforts provide insight into the utility of employing strict conservation for rSNP discovery. This strategy, combined with functional analyses, can yield candidate target genes. In support of this, our efforts suggest that investigating the role of Tubb2b in SOX10-positive cells may reveal novel biology within these cell populations. Electronic supplementary material The online version of this article (10.1186/s12864-018-4692-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- William D Law
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Elizabeth A Fogarty
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Aimée Vester
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA. .,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA. .,Department of Neurology, University of Michigan Medical School, 3710A Medical Sciences II, 1241 E. Catherine St. SPC 5618, Ann Arbor, MI, 48109, USA.
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57
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Gomis-Coloma C, Velasco-Aviles S, Gomez-Sanchez JA, Casillas-Bajo A, Backs J, Cabedo H. Class IIa histone deacetylases link cAMP signaling to the myelin transcriptional program of Schwann cells. J Cell Biol 2018; 217:1249-1268. [PMID: 29472387 PMCID: PMC5881490 DOI: 10.1083/jcb.201611150] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 10/06/2017] [Accepted: 01/17/2018] [Indexed: 12/11/2022] Open
Abstract
Schwann cells respond to cyclic adenosine monophosphate (cAMP) halting proliferation and expressing myelin proteins. Here we show that cAMP signaling induces the nuclear shuttling of the class IIa histone deacetylase (HDAC)-4 in these cells, where it binds to the promoter and blocks the expression of c-Jun, a negative regulator of myelination. To do it, HDAC4 does not interfere with the transcriptional activity of MEF2. Instead, by interacting with NCoR1, it recruits HDAC3 and deacetylates histone 3 in the promoter of c-Jun, blocking gene expression. Importantly, this is enough to up-regulate Krox20 and start Schwann cell differentiation program-inducing myelin gene expression. Using conditional knockout mice, we also show that HDAC4 together with HDAC5 redundantly contribute to activate the myelin transcriptional program and the development of myelin sheath in vivo. We propose a model in which cAMP signaling shuttles class IIa HDACs into the nucleus of Schwann cells to regulate the initial steps of myelination in the peripheral nervous system.
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Affiliation(s)
- Clara Gomis-Coloma
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones Científicas, Sant Joan, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL) and Fundación para el Fomento de la Investigación Saniatria y Biomédica de la Comunidad Valenciana (FISABIO), Alicante, Spain
| | - Sergio Velasco-Aviles
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones Científicas, Sant Joan, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL) and Fundación para el Fomento de la Investigación Saniatria y Biomédica de la Comunidad Valenciana (FISABIO), Alicante, Spain
| | - Jose A Gomez-Sanchez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones Científicas, Sant Joan, Alicante, Spain
- Department of Cell and Developmental Biology, University College London, London, England, UK
| | - Angeles Casillas-Bajo
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones Científicas, Sant Joan, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL) and Fundación para el Fomento de la Investigación Saniatria y Biomédica de la Comunidad Valenciana (FISABIO), Alicante, Spain
| | - Johannes Backs
- Department of Molecular Cardiology and Epigenetics, University of Heidelberg, Heidelberg, Germany
- German Center for Cardiovascular Research, Partner Site Heidelberg/Mannheim, Germany
| | - Hugo Cabedo
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones Científicas, Sant Joan, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL) and Fundación para el Fomento de la Investigación Saniatria y Biomédica de la Comunidad Valenciana (FISABIO), Alicante, Spain
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58
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Abstract
The journey of Schwann cells from their origin in the neural crest to their ensheathment and myelination of peripheral nerves is a remarkable one. Their apparent static function in enabling saltatory conduction of mature nerve is not only vital for long-term health of peripheral nerve but also belies an innate capacity of terminally differentiated Schwann cells to radically alter their differentiation status in the face of nerve injury. The transition from migrating neural crest cells to nerve ensheathment, and then myelination of large diameter axons has been characterized extensively and several of the transcriptional networks have been identified. However, transcription factors must also modify chromatin structure during Schwann cell maturation and this review will focus on chromatin modification machinery that is involved in promoting the transition to, and maintenance of, myelinating Schwann cells. In addition, Schwann cells are known to play important regenerative roles after peripheral nerve injury, and information on epigenomic reprogramming of the Schwann cell genome has emerged. Characterization of epigenomic requirements for myelin maintenance and Schwann cell responses to injury will be vital in understanding how the various Schwann cell functions can be optimized to maintain and repair peripheral nerve function.
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Affiliation(s)
- Ki H Ma
- 1 Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - John Svaren
- 1 Waisman Center, University of Wisconsin-Madison, Madison, WI, USA.,2 Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA
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59
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Dranchak P, Moran JJ, MacArthur R, Lopez-Anido C, Inglese J, Svaren J. Genome-Edited Cell Lines for High-Throughput Screening. Methods Mol Biol 2018; 1755:1-17. [PMID: 29671259 DOI: 10.1007/978-1-4939-7724-6_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Measurement of gene expression for high-throughput screening is an increasingly used technique that has been developed for not only gene dosage disorders resulting from disease-associated copy number variations, but also for induction/repression of genes modulating the severity of a disease phenotype. Traditional methods have employed transient or stable transfection of reporter constructs in which a single reporter is driven by selected regulatory elements from the candidate gene. However, individual regulatory elements are inherently unable to capture the integrated regulation of multiple enhancers at the endogenous locus, and random reporter insertion can result in neighborhood effects that impact the physiological responsiveness of the reporter. Therefore, we outline a general method of employing genome editing to insert reporters into the 3' UTR of a candidate gene, which has been used successfully in our studies of the Pmp22 gene associated with Charcot-Marie-Tooth disease. The method employs genome editing to insert two nonhomologous reporters that maximize the efficiency of identification of biologically active molecules through concordant responses in small molecule screening. We include a number of aspects of the design and construction of these reporter assays that will be applicable to creation of similar assays in a variety of cell types.
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Affiliation(s)
- Patricia Dranchak
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | - John J Moran
- Waisman Center, University of Wisconsin, Madison, WI, USA
| | - Ryan MacArthur
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | | | - James Inglese
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA.,National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - John Svaren
- Waisman Center, University of Wisconsin, Madison, WI, USA. .,Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA.
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60
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Liu JH, Tang Q, Liu XX, Qi J, Zeng RX, Zhu ZW, He B, Xu YB. Analysis of transcriptome sequencing of sciatic nerves in Sprague-Dawley rats of different ages. Neural Regen Res 2018; 13:2182-2190. [PMID: 30323151 PMCID: PMC6199923 DOI: 10.4103/1673-5374.241469] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An aging-induced decrease in Schwann cell viability can affect regeneration following peripheral nerve injury in mammals. It is therefore necessary to investigate possible age-related changes in gene expression that may affect the biological function of peripheral nerves. Ten 1-week-old and ten 12-month-old healthy male Sprague-Dawley rats were divided into young (1 week old) and adult (12 months old) groups according to their ages. mRNA expression in the sciatic nerve was compared between young and adult rats using next-generation sequencing (NGS) and bioinformatics (n = 4/group). The 18 groups of differentially expressed mRNA (DEmRNAs) were also tested by quantitative reverse transcription polymerase chain reaction (n = 6/group). Results revealed that (1) compared with young rats, adult rats had 3608 groups of DEmRNAs. Of these, 2684 were groups of upregulated genes, and 924 were groups of downregulated genes. Their functions mainly involved cell viability, proliferation, differentiation, regeneration, and myelination. (2) The gene with the most obvious increase of all DEmRNAs in adult rats was Thrsp (log2 FC = 9.01, P < 0.05), and the gene with the most obvious reduction was Col2a1 (log2FC = –8.89, P < 0.05). (3) Gene Ontology analysis showed that DEmRNAs were mainly concentrated in oligosaccharide binding, nucleotide-binding oligomerization domain containing one signaling pathway, and peptide-transporting ATPase activity. (4) Analysis using the Kyoto Encyclopedia of Genes and Genomes showed that, with increased age, DEmRNAs were mainly enriched in steroid biosynthesis, Staphylococcus aureus infection, and graft-versus-host disease. (5) Spearman's correlation coefficient method for evaluating NGS accuracy showed that the NGS results and quantitative reverse transcription polymerase chain reaction results were positively correlated (rs = 0.74, P < 0.05). These findings confirm a difference in sciatic nerve gene expression between adult and young rats, suggesting that, in peripheral nerves, cells and the microenvironment change with age, thus influencing the function and repair of peripheral nerves.
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Affiliation(s)
- Jiang-Hui Liu
- Department of Emergency, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Qing Tang
- Department of Plastic Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Xiang-Xia Liu
- Department of Plastic Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Jian Qi
- Department of Orthopedics and Microsurgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Rui-Xi Zeng
- Department of Plastic Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Zhao-Wei Zhu
- Department of Plastic Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Bo He
- Department of Orthopedics, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Yang-Bin Xu
- Department of Plastic Surgery, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
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61
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Fazal SV, Gomez-Sanchez JA, Wagstaff LJ, Musner N, Otto G, Janz M, Mirsky R, Jessen KR. Graded Elevation of c-Jun in Schwann Cells In Vivo: Gene Dosage Determines Effects on Development, Remyelination, Tumorigenesis, and Hypomyelination. J Neurosci 2017; 37:12297-12313. [PMID: 29109239 PMCID: PMC5729195 DOI: 10.1523/jneurosci.0986-17.2017] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/22/2017] [Accepted: 10/08/2017] [Indexed: 11/21/2022] Open
Abstract
Schwann cell c-Jun is implicated in adaptive and maladaptive functions in peripheral nerves. In injured nerves, this transcription factor promotes the repair Schwann cell phenotype and regeneration and promotes Schwann-cell-mediated neurotrophic support in models of peripheral neuropathies. However, c-Jun is associated with tumor formation in some systems, potentially suppresses myelin genes, and has been implicated in demyelinating neuropathies. To clarify these issues and to determine how c-Jun levels determine its function, we have generated c-Jun OE/+ and c-Jun OE/OE mice with graded expression of c-Jun in Schwann cells and examined these lines during development, in adulthood, and after injury using RNA sequencing analysis, quantitative electron microscopic morphometry, Western blotting, and functional tests. Schwann cells are remarkably tolerant of elevated c-Jun because the nerves of c-Jun OE/+ mice, in which c-Jun is elevated ∼6-fold, are normal with the exception of modestly reduced myelin thickness. The stronger elevation of c-Jun in c-Jun OE/OE mice is, however, sufficient to induce significant hypomyelination pathology, implicating c-Jun as a potential player in demyelinating neuropathies. The tumor suppressor P19ARF is strongly activated in the nerves of these mice and, even in aged c-Jun OE/OE mice, there is no evidence of tumors. This is consistent with the fact that tumors do not form in injured nerves, although they contain proliferating Schwann cells with strikingly elevated c-Jun. Furthermore, in crushed nerves of c-Jun OE/+ mice, where c-Jun levels are overexpressed sufficiently to accelerate axonal regeneration, myelination and function are restored after injury.SIGNIFICANCE STATEMENT In injured and diseased nerves, the transcription factor c-Jun in Schwann cells is elevated and variously implicated in controlling beneficial or adverse functions, including trophic Schwann cell support for neurons, promotion of regeneration, tumorigenesis, and suppression of myelination. To analyze the functions of c-Jun, we have used transgenic mice with graded elevation of Schwann cell c-Jun. We show that high c-Jun elevation is a potential pathogenic mechanism because it inhibits myelination. Conversely, we did not find a link between c-Jun elevation and tumorigenesis. Modest c-Jun elevation, which is beneficial for regeneration, is well tolerated during Schwann cell development and in the adult and is compatible with restoration of myelination and nerve function after injury.
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Affiliation(s)
- Shaline V Fazal
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Jose A Gomez-Sanchez
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Laura J Wagstaff
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | | | - Georg Otto
- University College London Great Ormond Street Institute of Child Health, London WC1N1EH, United Kingdom, and
| | - Martin Janz
- Max Delbrück Center for Molecular Medicine and Charité, University Hospital Berlin, Campus Benjamin Franklin, 13092 Berlin, Germany
| | - Rhona Mirsky
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom,
| | - Kristján R Jessen
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom,
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62
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Miz1 Controls Schwann Cell Proliferation via H3K36 me2 Demethylase Kdm8 to Prevent Peripheral Nerve Demyelination. J Neurosci 2017; 38:858-877. [PMID: 29217679 DOI: 10.1523/jneurosci.0843-17.2017] [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: 03/28/2017] [Revised: 11/15/2017] [Accepted: 11/17/2017] [Indexed: 12/21/2022] Open
Abstract
Schwann cell differentiation and myelination depends on chromatin remodeling, histone acetylation, and methylation, which all affect Schwann cell proliferation. We previously reported that the deletion of the POZ (POxvirus and Zinc finger) domain of the transcription factor Miz1 (Myc-interacting zinc finger protein; encoded by Zbtb17) in mouse Schwann cells (Miz1ΔPOZ) causes a neuropathy at 90 d after birth [postnatal day (P) 90], with a subsequent spontaneous regeneration. Here we show that RNA sequencing from Miz1ΔPOZ and control animals at P30 revealed a set of upregulated genes with a strong correlation to cell-cycle regulation. Consistently, a subset of Schwann cells did not exit the cell cycle as observed in control animals and the growth fraction increased over time. From the RNAseq gene list, two direct Miz1 target genes were identified, one of which encodes the histone H3K36me2 demethylase Kdm8. We show that the expression of Kdm8 is repressed by Miz1 and that its release in Miz1ΔPOZ cells induces a decrease of H3K36me2, especially in deregulated cell-cycle-related genes. The linkage between elevated Kdm8 expression, hypomethylation of H3K36 at cell-cycle-relevant genes, and the subsequent re-entering of adult Schwann cells into the cell cycle suggests that the release of Kdm8 repression in the absence of a functional Miz1 is a central issue in the development of the Miz1ΔPOZ phenotype.SIGNIFICANCE STATEMENT The deletion of the Miz1 (Myc-interacting zinc finger protein 1) POZ (POxvirus and Zinc finger) domain in Schwann cells causes a neuropathy. Here we report sustained Schwann cell proliferation caused by an increased expression of the direct Miz1 target gene Kdm8, encoding a H3K36me2 demethylase. Hence, the demethylation of H3K36 is linked to the pathogenesis of a neuropathy.
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63
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Aging Schwann cells: mechanisms, implications, future directions. Curr Opin Neurobiol 2017; 47:203-208. [DOI: 10.1016/j.conb.2017.10.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/11/2017] [Accepted: 10/24/2017] [Indexed: 12/17/2022]
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Therapeutic Effect of Vinorine on Sciatic Nerve Injured Rat. Neurochem Res 2017; 43:375-386. [PMID: 29119332 DOI: 10.1007/s11064-017-2432-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/14/2022]
Abstract
Vinorine is a monoterpenoid indole alkaloid, a type of natural alkaloids. Growing reports exhibited the numerous pharmacology activities of vinorine such as anti-inflammation, anti-bacterial and anti-tumor. In this study, the effect of vinorine injection (7.5, 15 and 30 mg/kg) on motor function, sensation and nerve regeneration in sciatic nerve crush injury rat was investigated. The results of behavioral analysis, electrophysiological analysis and muscle histological analysis suggested that vinorine promoted the motor function recovery after sciatic nerve injury. The results of mechanical withdrawal thresholds assay and hot plate test demonstrated that vinorine improved the sensation recovery after sciatic nerve injury. The results of Fluoro-gold retrograde labeling, transmission electron microscope assay, toluidine blue and HE staining showed that vinorine attenuated the nerve damage caused by sciatic nerve injury and promoted the nerve regeneration. Furthermore, nerve growth factor (NGF) and its downstream extracellular signal-regulated kinase (ERK) signaling pathway participated in the neuro-recovery effect of vinorine after crush. In conclusion, vinorine treatment accelerated the sciatic nerve regeneration, motor function recovery and sensation recovery after crush injury via regulation of NGF and ERK activity. These results suggested that vinorine is a promising agent for never injury therapy.
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Clements MP, Byrne E, Camarillo Guerrero LF, Cattin AL, Zakka L, Ashraf A, Burden JJ, Khadayate S, Lloyd AC, Marguerat S, Parrinello S. The Wound Microenvironment Reprograms Schwann Cells to Invasive Mesenchymal-like Cells to Drive Peripheral Nerve Regeneration. Neuron 2017; 96:98-114.e7. [PMID: 28957681 PMCID: PMC5626803 DOI: 10.1016/j.neuron.2017.09.008] [Citation(s) in RCA: 211] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 07/07/2017] [Accepted: 09/06/2017] [Indexed: 01/05/2023]
Abstract
Schwann cell dedifferentiation from a myelinating to a progenitor-like cell underlies the remarkable ability of peripheral nerves to regenerate following injury. However, the molecular identity of the differentiated and dedifferentiated states in vivo has been elusive. Here, we profiled Schwann cells acutely purified from intact nerves and from the wound and distal regions of severed nerves. Our analysis reveals novel facets of the dedifferentiation response, including acquisition of mesenchymal traits and a Myc module. Furthermore, wound and distal dedifferentiated Schwann cells constitute different populations, with wound cells displaying increased mesenchymal character induced by localized TGFβ signaling. TGFβ promotes invasion and crosstalks with Eph signaling via N-cadherin to drive collective migration of the Schwann cells across the wound. Consistently, Tgfbr2 deletion in Schwann cells resulted in misdirected and delayed reinnervation. Thus, the wound microenvironment is a key determinant of Schwann cell identity, and it promotes nerve repair through integration of multiple concerted signals. VIDEO ABSTRACT.
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Affiliation(s)
- Melanie P Clements
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Elizabeth Byrne
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Luis F Camarillo Guerrero
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom; Quantitative Gene Expression Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom
| | - Anne-Laure Cattin
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Leila Zakka
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Azhaar Ashraf
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Jemima J Burden
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Sanjay Khadayate
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Alison C Lloyd
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom; UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, United Kingdom
| | - Samuel Marguerat
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom; Quantitative Gene Expression Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom
| | - Simona Parrinello
- Cell Interactions and Cancer Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom.
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Arthur-Farraj PJ, Morgan CC, Adamowicz M, Gomez-Sanchez JA, Fazal SV, Beucher A, Razzaghi B, Mirsky R, Jessen KR, Aitman TJ. Changes in the Coding and Non-coding Transcriptome and DNA Methylome that Define the Schwann Cell Repair Phenotype after Nerve Injury. Cell Rep 2017; 20:2719-2734. [PMID: 28903050 PMCID: PMC5608958 DOI: 10.1016/j.celrep.2017.08.064] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/17/2017] [Accepted: 08/18/2017] [Indexed: 12/12/2022] Open
Abstract
Repair Schwann cells play a critical role in orchestrating nerve repair after injury, but the cellular and molecular processes that generate them are poorly understood. Here, we perform a combined whole-genome, coding and non-coding RNA and CpG methylation study following nerve injury. We show that genes involved in the epithelial-mesenchymal transition are enriched in repair cells, and we identify several long non-coding RNAs in Schwann cells. We demonstrate that the AP-1 transcription factor C-JUN regulates the expression of certain micro RNAs in repair Schwann cells, in particular miR-21 and miR-34. Surprisingly, unlike during development, changes in CpG methylation are limited in injury, restricted to specific locations, such as enhancer regions of Schwann cell-specific genes (e.g., Nedd4l), and close to local enrichment of AP-1 motifs. These genetic and epigenomic changes broaden our mechanistic understanding of the formation of repair Schwann cell during peripheral nervous system tissue repair.
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Affiliation(s)
- Peter J Arthur-Farraj
- Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK; Department of Medicine, Imperial College, London W12 0NN, UK; Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
| | - Claire C Morgan
- Department of Medicine, Imperial College, London W12 0NN, UK
| | - Martyna Adamowicz
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH16 2XU, UK
| | - Jose A Gomez-Sanchez
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Shaline V Fazal
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Anthony Beucher
- Department of Medicine, Imperial College, London W12 0NN, UK
| | - Bonnie Razzaghi
- Department of Medicine, Imperial College, London W12 0NN, UK
| | - Rhona Mirsky
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Kristjan R Jessen
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Timothy J Aitman
- Department of Medicine, Imperial College, London W12 0NN, UK; Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH16 2XU, UK.
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Jacob C. Chromatin-remodeling enzymes in control of Schwann cell development, maintenance and plasticity. Curr Opin Neurobiol 2017; 47:24-30. [PMID: 28850819 DOI: 10.1016/j.conb.2017.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/28/2017] [Accepted: 08/10/2017] [Indexed: 01/06/2023]
Abstract
Gene regulation is essential for cellular differentiation and plasticity. Schwann cells (SCs), the myelinating glia of the peripheral nervous system (PNS), develop from neural crest cells to mature myelinating SCs and can at early developmental stage differentiate into various cell types. After a PNS lesion, SCs can also convert into repair cells that guide and stimulate axonal regrowth, and remyelinate regenerated axons. What controls their development and versatile nature? Several recent studies highlight the key roles of chromatin modifiers in these processes, allowing SCs to regulate their gene expression profile and thereby acquire or change their identity and quickly react to their environment.
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Affiliation(s)
- Claire Jacob
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
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Hsieh CH, Rau CS, Kuo PJ, Liu SH, Wu CJ, Lu TH, Wu YC, Lin CW. Knockout of toll-like receptor impairs nerve regeneration after a crush injury. Oncotarget 2017; 8:80741-80756. [PMID: 29113341 PMCID: PMC5655236 DOI: 10.18632/oncotarget.20206] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/12/2017] [Indexed: 01/01/2023] Open
Abstract
Background Toll-like receptors (TLRs) are involved in the initiation of Schwann cell activation and subsequent recruitment of macrophages for clearance of degenerated myelin and neuronal debris after nerve injury. The present study was designed to investigate the regenerative outcome and expression of myelination-related factors in Tlr-knockout mice following a sciatic nerve crush injury. Materials and methods A standard sciatic nerve crush injury, induced by applying constant pressure to the nerve with a No. 5 jeweler's forceps for 30 s, was performed in C57BL/6, Tlr2−/−, Tlr3−/−, Tlr4−/−, Tlr5−/−, and Tlr7−/− mice. Quantitative histomorphometric analysis of toluidine blue-stained nerve specimens and walking track analysis were performed to evaluate nerve regeneration outcomes. PCR Arrays were used to detect the expression of neurogenesis-related genes of dorsal root ganglia as well as of myelination-related genes of the distal nerve segments. Results Worse nerve regeneration after nerve crush injury was found in all Tlr-knockout mice than in C57BL/6 mice. Delayed expression of myelin genes and a different expression pattern of myelination-related neurotrophin genes and transcription factors were found in Tlr-knockout mice in comparison to C57BL/6 mice. In these TLR-mediated pathways, insulin-like growth factor 2 and brain-derived neurotrophic factor, as well as early growth response 2 and N-myc downstream-regulated gene 1, were significantly decreased in the early and late stages, respectively, of nerve regeneration after a crush injury. Conclusions Knockout of Tlr genes decreases the expression of myelination-related factors and impairs nerve regeneration after a sciatic nerve crush injury.
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Affiliation(s)
- Ching-Hua Hsieh
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.,Center for Vascularized Composite Allotransplantation, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Cheng-Shyuan Rau
- Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Pao-Jen Kuo
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Shu-Hsuan Liu
- Faculty of Health Sciences, McMaster University, Hamilton, Canada
| | - Chia-Jung Wu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tsu-Hsiang Lu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yi-Chan Wu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chia-Wei Lin
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Tricaud N, Park HT. Wallerian demyelination: chronicle of a cellular cataclysm. Cell Mol Life Sci 2017; 74:4049-4057. [PMID: 28600652 PMCID: PMC5641270 DOI: 10.1007/s00018-017-2565-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/10/2017] [Accepted: 06/01/2017] [Indexed: 12/23/2022]
Abstract
Wallerian demyelination is characteristic of peripheral nerve degeneration after traumatic injury. After axonal degeneration, the myelinated Schwann cell undergoes a stereotypical cellular program that results in the disintegration of the myelin sheath, a process termed demyelination. In this review, we chronologically describe this program starting from the late and visible features of myelin destruction and going backward to the initial molecular steps that trigger the nuclear reprogramming few hours after injury. Wallerian demyelination is a wonderful model for myelin degeneration occurring in the diverse forms of demyelinating peripheral neuropathies that plague human beings.
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Affiliation(s)
- Nicolas Tricaud
- INSERM U1051, Institut des Neurosciences de Montpellier (INM), Université de Montpellier, Montpellier, France.
| | - Hwan Tae Park
- Peripheral Neuropathy Research Center, Department of Physiology, College of Medicine, Dong-A University, Busan, South Korea
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A reciprocal regulatory loop between TAZ/YAP and G-protein Gαs regulates Schwann cell proliferation and myelination. Nat Commun 2017; 8:15161. [PMID: 28443644 PMCID: PMC5414202 DOI: 10.1038/ncomms15161] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 03/03/2017] [Indexed: 02/06/2023] Open
Abstract
Schwann cell (SC) myelination in the peripheral nervous system is essential for motor function, and uncontrolled SC proliferation occurs in cancer. Here, we show that a dual role for Hippo effectors TAZ and YAP in SC proliferation and myelination through modulating G-protein expression and interacting with SOX10, respectively. Developmentally regulated mutagenesis indicates that TAZ/YAP are critical for SC proliferation and differentiation in a stage-dependent manner. Genome-wide occupancy mapping and transcriptome profiling reveal that nuclear TAZ/YAP promote SC proliferation by activating cell cycle regulators, while targeting critical differentiation regulators in cooperation with SOX10 for myelination. We further identify that TAZ targets and represses Gnas, encoding Gαs-protein, which opposes TAZ/YAP activities to decelerate proliferation. Gnas deletion expands SC precursor pools and blocks peripheral myelination. Thus, the Hippo/TAZ/YAP and Gαs-protein feedback circuit functions as a fulcrum balancing SC proliferation and differentiation, providing insights into molecular programming of SC lineage progression and homeostasis. The Hippo pathway has recently been implicated in Schwann cell (SC) development and myelination. Here the authors reveal mechanistic insights into how TAZ and YAP regulate and interact with target genes; they further identify a negative feedback loop between TAZ/YAP and G protein Gαs that balances SC proliferation and differentiation.
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71
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Comparison of DNA Methylation in Schwann Cells before and after Peripheral Nerve Injury in Rats. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5393268. [PMID: 28459064 PMCID: PMC5385226 DOI: 10.1155/2017/5393268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/23/2017] [Accepted: 03/08/2017] [Indexed: 01/13/2023]
Abstract
This study aims to find the difference of genomewide DNA methylation in Schwann cells (SCs) before and after peripheral nerve system (PNS) injury by Methylated DNA Immunoprecipitation Sequencing (MeDIP-Seq) and seek meaningful differentially methylated genes related to repairment of injured PNS. SCs harvested from sciatic nerve were named as activated Schwann cells (ASCs), and the ones harvested from brachial plexus were named as normal Schwann cells (NSCs). Genomic DNA of ASCs and NSCs were isolated and MeDIP-Seq was conducted. Differentially methylated genes and regions were discovered and analyzed by bioinformatic methods. MeDIP-Seq analysis showed methylation differences were identified between ASCs and NSCs. The distribution of differentially methylated regions (DMRs) peaks in different components of genome was mainly located in distal intergenic regions. GO and KEGG analysis of these methylated genes were also conducted. The expression patterns of hypermethylated genes (Dgcr8, Zeb2, Dixdc1, Sox2, and Shh) and hypomethylated genes (Gpr126, Birc2) detected by qRT-PCR were opposite to the MeDIP analysis data with significance (p < 0.05), which proved MeDIP analysis data were real and believable. Our data serve as a basis for understanding the injury-induced epigenetic changes in SCs and the foundation for further studies on repair of PNS injury.
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72
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New insights into the ameliorative effects of ferulic acid in pathophysiological conditions. Food Chem Toxicol 2017; 103:41-55. [PMID: 28237775 DOI: 10.1016/j.fct.2017.02.028] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/16/2017] [Accepted: 02/20/2017] [Indexed: 12/21/2022]
Abstract
Ferulic acid, a natural phytochemical has gained importance as a potential therapeutic agent by virtue of its easy commercial availability, low cost and minimal side-effects. It is a derivative of curcumin and possesses the necessary pharmacokinetic properties to be retained in the general circulation for several hours. The therapeutic effects of ferulic acid are mediated through its antioxidant and anti-inflammatory properties. It exhibits different biological activities such as anti-inflammatory, anti-apoptotic, anti-carcinogenic, anti-diabetic, hepatoprotective, cardioprotective, neuroprotective actions, etc. The current review addresses its therapeutic effects under different pathophysiological conditions (eg. cancer, cardiomyopathy, skin disorders, brain disorders, viral infections, diabetes etc.).
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Rodríguez-Molina JF, Lopez-Anido C, Ma KH, Zhang C, Olson T, Muth KN, Weider M, Svaren J. Dual specificity phosphatase 15 regulates Erk activation in Schwann cells. J Neurochem 2017; 140:368-382. [PMID: 27891578 PMCID: PMC5250571 DOI: 10.1111/jnc.13911] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/15/2016] [Accepted: 11/21/2016] [Indexed: 12/20/2022]
Abstract
Schwann cells and oligodendrocytes are the myelinating cells of the peripheral and central nervous system, respectively. Despite having different myelin components and different transcription factors driving their terminal differentiation there are shared molecular mechanisms between the two. Sox10 is one common transcription factor required for several steps in development of myelinating glia. However, other factors are divergent as Schwann cells need the transcription factor early growth response 2/Krox20 and oligodendrocytes require Myrf. Likewise, some signaling pathways, like the Erk1/2 kinases, are necessary in both cell types for proper myelination. Nonetheless, the molecular mechanisms that control this shared signaling pathway in myelinating cells remain only partially characterized. The hypothesis of this study is that signaling pathways that are similarly regulated in both Schwann cells and oligodendrocytes play central roles in coordinating the differentiation of myelinating glia. To address this hypothesis, we have used genome-wide binding data to identify a relatively small set of genes that are similarly regulated by Sox10 in myelinating glia. We chose one such gene encoding Dual specificity phosphatase 15 (Dusp15) for further analysis in Schwann cell signaling. RNA interference and gene deletion by genome editing in cultured RT4 and primary Schwann cells showed Dusp15 is necessary for full activation of Erk1/2 phosphorylation. In addition, we show that Dusp15 represses expression of several myelin genes, including myelin basic protein. The data shown here support a mechanism by which early growth response 2 activates myelin genes, but also induces a negative feedback loop through Dusp15 to limit over-expression of myelin genes.
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Affiliation(s)
- José F. Rodríguez-Molina
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Camila Lopez-Anido
- Comparative Biomedical Sciences Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ki H. Ma
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Chongyu Zhang
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tyler Olson
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Katharina N. Muth
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Matthias Weider
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - John Svaren
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53705, USA
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Wang JW, Stifani S. Roles of Runx Genes in Nervous System Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:103-116. [PMID: 28299654 DOI: 10.1007/978-981-10-3233-2_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Runt-related (Runx) transcription factors play essential roles during development and adult tissue homeostasis and are responsible for several human diseases. They regulate a variety of biological mechanisms in numerous cell lineages. Recent years have seen significant progress in our understanding of the functions performed by Runx proteins in the developing and postnatal mammalian nervous system. In both central and peripheral nervous systems, Runx1 and Runx3 display remarkably specific expression in mostly non-overlapping groups of postmitotic neurons. In the central nervous system, Runx1 is involved in the development of selected motor neurons controlling neural circuits mediating vital functions such as chewing, swallowing, breathing, and locomotion. In the peripheral nervous system, Runx1 and Runx3 play essential roles during the development of sensory neurons involved in circuits mediating pain, itch, thermal sensation and sense of relative position. Runx1 and Runx3 orchestrate complex gene expression programs controlling neuronal subtype specification and axonal connectivity. Runx1 is also important in the olfactory system, where it regulates the progenitor-to-neuron transition in undifferentiated neural progenitor cells in the olfactory epithelium as well as the proliferation and developmental maturation of specific glial cells termed olfactory ensheathing cells. Moreover, upregulated Runx expression is associated with brain injury and disease. Increasing knowledge of the functions of Runx proteins in the developing and postnatal nervous system is therefore expected to improve our understanding of nervous system development, homeostasis and disease.
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Affiliation(s)
- Jae Woong Wang
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A2B4, Canada
| | - Stefano Stifani
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A2B4, Canada.
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Xiang F, Wei D, Yang Y, Chi H, Yang K, Sun Y. Tissue-engineered nerve graft with tetramethylpyrazine for repair of sciatic nerve defects in rats. Neurosci Lett 2016; 638:114-120. [PMID: 27988347 DOI: 10.1016/j.neulet.2016.12.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/09/2016] [Accepted: 12/13/2016] [Indexed: 12/16/2022]
Abstract
A tissue-engineered nerve with tetramethylpyrazine (TMP) was repaired for sciatic nerve defects in rats. A total of 55 adult Sprague Dawley (SD) rats were classified into 4 groups, with 15 rats in each of groups A, B, and C as well as 10 rats in group D. About 1.5cm of a sciatic nerve of the right hind limb located 0.5cm below the inferior margin of the piriformis was resected to form the defects. Four types of nerve grafts used for bridging nerve defects in the SD rats corresponded to the 4 groups: tissue-engineered nerves with TMP in group A, tissue-engineered nerves without TMP in group B, acellular nerve grafts (ANGs) in group C, and autologous nerves in group D. Twelve weeks post-surgery, the sciatic functional index, nerve conduction velocity, and gastrocnemius wet weight of groups A and D were higher than those of groups B and C (P<0.05). Results of fluorescence microscopy and histological staining indicated that group A performed better than groups B and C (P<0.05). Similarly, the number of horseradish peroxidase-labeled positive cells was significantly larger in group A than in groups B and C. Regenerative nerve fibers were abundant in group A and consisted mainly of myelinated nerve fibers, which were better than those in groups B and C (P<0.05). The study demonstrated that tissue-engineered nerves constructed by ANGs seeded with neural stem cells and combined with TMP can effectively repair sciatic nerve defects in rats.
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Affiliation(s)
- Feifan Xiang
- Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Daiqing Wei
- Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Yunkang Yang
- Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
| | - Haotian Chi
- Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Kun Yang
- Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Yuanlin Sun
- Department of Bone and Joint Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
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76
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Weng YL, Joseph J, An R, Song H, Ming GL. Epigenetic regulation of axonal regenerative capacity. Epigenomics 2016; 8:1429-1442. [PMID: 27642866 DOI: 10.2217/epi-2016-0058] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The intrinsic growth capacity of neurons in the CNS declines during neuronal maturation, while neurons in the adult PNS are capable of regeneration. Injured mature PNS neurons require activation of an array of regeneration-associated genes to regain axonal growth competence. Accumulating evidence indicates a pivotal role of epigenetic mechanisms in transcriptional reprogramming and regulation of neuronal growth ability upon injury. In this review, we summarize the latest findings implicating epigenetic mechanisms, including histone and DNA modifications, in axon regeneration and discuss differential epigenomic configurations between neurons in the adult mammalian CNS and PNS.
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Affiliation(s)
- Yi-Lan Weng
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica Joseph
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Graduate Program in Cellular & Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ran An
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hongjun Song
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Graduate Program in Cellular & Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guo-Li Ming
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Graduate Program in Cellular & Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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77
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Ma KH, Hung HA, Svaren J. Epigenomic Regulation of Schwann Cell Reprogramming in Peripheral Nerve Injury. J Neurosci 2016; 36:9135-47. [PMID: 27581455 PMCID: PMC5005723 DOI: 10.1523/jneurosci.1370-16.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/08/2016] [Accepted: 07/15/2016] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED The rapid and dynamic transcriptional changes of Schwann cells in response to injury are critical to peripheral nerve repair, yet the epigenomic reprograming that leads to the induction of injury-activated genes has not been characterized. Polycomb Repressive Complex 2 (PRC2) catalyzes the trimethylation of lysine 27 of histone H3 (H3K27me3), which produces a transcriptionally repressive chromatin environment. We find that many promoters and/or gene bodies of injury-activated genes of mature rat nerves are occupied with H3K27me3. In contrast, the majority of distal enhancers that gain H3K27 acetylation after injury are not repressed by H3K27 methylation before injury, which is normally observed in developmentally poised enhancers. Injury induces demethylation of H3K27 in many genes, such as Sonic hedgehog (Shh), which is silenced throughout Schwann cell development before injury. In addition, experiments using a Schwann cell-specific mouse knock-out of the Eed subunit of PRC2 indicate that demethylation is a rate-limiting step in the activation of such genes. We also show that some transcription start sites of H3K27me3-repressed injury genes of uninjured nerves are bound with a mark of active promoters H3K4me3, for example, Shh and Gdnf, and the reduction of H3K27me3 results in increased trimethylation of H3K4. Our findings identify reversal of polycomb repression as a key step in gene activation after injury. SIGNIFICANCE STATEMENT Peripheral nerve regeneration after injury is dependent upon implementation of a novel genetic program in Schwann cells that supports axonal survival and regeneration. Identifying means to enhance Schwann cell reprogramming after nerve injury could be used to foster effective remyelination in the treatment of demyelinating disorders and in identifying pathways involved in regenerative process of myelination. Although recent progress has identified transcriptional determinants of successful reprogramming of the Schwann cell transcriptome after nerve injury, our results have highlighted a novel epigenomic pathway in which reversal of the Polycomb pathway of repressive histone methylation is required for activation of a significant number of injury-induced genes.
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Affiliation(s)
- Ki H Ma
- Waisman Center, Cellular and Molecular Pathology Graduate Program, and
| | - Holly A Hung
- Waisman Center, Cellular and Molecular Pathology Graduate Program, and
| | - John Svaren
- Waisman Center, Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin 53705
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78
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Zhu X, Li K, Guo X, Wang J, Xiang Y. Schwann cell proliferation and differentiation that is induced by ferulic acid through MEK1/ERK1/2 signalling promotes peripheral nerve remyelination following crush injury in rats. Exp Ther Med 2016; 12:1915-1921. [PMID: 27588110 DOI: 10.3892/etm.2016.3525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 05/10/2016] [Indexed: 11/06/2022] Open
Abstract
Schwann cell proliferation and differentiation is critical for the remyelination of injured peripheral nerves. Ferulic acid (FA) is a widely used antioxidant agent with neuroprotective properties. However, the potentially beneficial effects of FA on Schwann cells are unknown. Therefore, the present study was designed to examine the effects of FA on Schwann cell proliferation and differentiation. By using the cultured primary Schwann cells and proliferation assay, the results identified that FA was capable of increasing Schwann cell proliferation and expression of myelin-associated glycoprotein (MAG) and myelin basic protein (MBP) in vitro. It was also observed that the beneficial effect of FA treatment on Schwann cells was mainly dependent on the activation of MEK1/ERK1/2 signalling. Furthermore, FA was intraperitoneally administered to rats with sciatic nerve crush injury, and the results revealed an increase in Schwann cell proliferation and differentiation, while the MAG and MBP expression levels in sciatic nerves were markedly upregulated following FA administration. In conclusion, the current results demonstrate that Schwann cell proliferation and differentiation is induced by FA through MEK1/ERK1/2 signalling and that FA may accelerate injured peripheral nerve remyelination.
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Affiliation(s)
- Xiaoyan Zhu
- Center of Laboratory Medicine, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Kun Li
- Center of Laboratory Medicine, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Xin Guo
- Center of Laboratory Medicine, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Jian Wang
- Department of Neurology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Yang Xiang
- Department of Neurology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
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79
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Lopez-Anido C, Poitelon Y, Gopinath C, Moran JJ, Ma KH, Law WD, Antonellis A, Feltri ML, Svaren J. Tead1 regulates the expression of Peripheral Myelin Protein 22 during Schwann cell development. Hum Mol Genet 2016; 25:3055-3069. [PMID: 27288457 DOI: 10.1093/hmg/ddw158] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/14/2016] [Accepted: 05/18/2016] [Indexed: 12/17/2022] Open
Abstract
Schwann cells are myelinating glia in the peripheral nervous system that form the myelin sheath. A major cause of peripheral neuropathy is a copy number variant involving the Peripheral Myelin Protein 22 (PMP22) gene, which is located within a 1.4-Mb duplication on chromosome 17 associated with the most common form of Charcot-Marie-Tooth Disease (CMT1A). Rodent models of CMT1A have been used to show that reducing Pmp22 overexpression mitigates several aspects of a CMT1A-related phenotype. Mechanistic studies of Pmp22 regulation identified enhancers regulated by the Sox10 (SRY sex determining region Y-box 10) and Egr2/Krox20 (Early growth response protein 2) transcription factors in myelinated nerves. However, relatively little is known regarding how other transcription factors induce Pmp22 expression during Schwann cell development and myelination. Here, we examined Pmp22 enhancers as a function of cell type-specificity, nerve injury and development. While Pmp22 enhancers marked by active histone modifications were lost or remodeled after injury, we found that these enhancers were permissive in early development prior to Pmp22 upregulation. Pmp22 enhancers contain binding motifs for TEA domain (Tead) transcription factors of the Hippo signaling pathway. We discovered that Tead1 and co-activators Yap and Taz are required for Pmp22 expression, as well as for the expression of Egr2 Tead1 directly binds Pmp22 and Egr2 enhancers early in development and Tead1 binding is induced during myelination, correlating with Pmp22 expression. The data identify Tead1 as a novel regulator of Pmp22 expression during development in concert with Sox10 and Egr2.
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Affiliation(s)
- Camila Lopez-Anido
- Waisman Center, Madison, WI, USA.,Comparative Biomedical Sciences Graduate Program, Madison, WI, USA
| | | | - Chetna Gopinath
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Ki Hwan Ma
- Waisman Center, Madison, WI, USA.,Cellular and Molecular Pathology Graduate Program, Madison, WI, USA
| | - William D Law
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anthony Antonellis
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - M Laura Feltri
- Hunter James Kelly Research Institute, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - John Svaren
- Waisman Center, Madison, WI, USA .,Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53705, USA
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80
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YAP and TAZ control peripheral myelination and the expression of laminin receptors in Schwann cells. Nat Neurosci 2016; 19:879-87. [PMID: 27273766 PMCID: PMC4925303 DOI: 10.1038/nn.4316] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 05/04/2016] [Indexed: 12/13/2022]
Abstract
Myelination is essential for nervous system function. Schwann cells interact with neurons and the basal lamina to myelinate axons, using known receptors, signals and transcription factors. In contrast, the transcriptional control of axonal sorting and the role of mechanotransduction in myelination are largely unknown. Yap and Taz are effectors of the Hippo pathway that integrate chemical and mechanical signals in cells. We describe a previously unknown role for the Hippo pathway in myelination. Using conditional mutagenesis in mice we show that Taz is required in Schwann cells for radial sorting and myelination, and that Yap is redundant with Taz. Yap/Taz are activated in Schwann cells by mechanical stimuli, and regulate Schwann cell proliferation and transcription of basal lamina receptor genes, both necessary for proper radial sorting of axons and subsequent myelination. These data link transcriptional effectors of the Hippo pathway and of mechanotransduction to myelin formation in Schwann cells.
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81
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Affiliation(s)
- Ki H Ma
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA; Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI, USA
| | - John Svaren
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA; Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI, USA; Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA
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82
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Zhang W, Liu Y, Zhu X, Cao Y, Liu Y, Mao X, Yang H, Zhou Z, Wang Y, Shen A. SCY1-Like 1-Binding Protein 1 (SCYL1BP1) Suppressed Sciatic Nerve Regeneration by Enhancing the RhoA Pathway. Mol Neurobiol 2015; 53:6342-6354. [PMID: 26572638 DOI: 10.1007/s12035-015-9531-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 11/08/2015] [Indexed: 12/13/2022]
Abstract
SCY1-like 1-binding protein 1 (SCYL1BP1) is first identified as an interacting protein with SCYL1. Since SCYL1BP1 is a soluble protein with coiled-coil domains known to be relevant with transcriptional regulation, it has been found to activate the transcription of murine double minute 2 (MDM2) and participate in neurite outgrowth and regeneration. However, the role and mechanism of SCYL1BP1 in peripheral nerve system lesion and repair are still unknown. Here in vitro, our work demonstrated that SCYL1BP1 inhibited cAMP-induced primary Schwann cell differentiation and suppressed nerve growth factor-mediated neurite outgrowth in PC12 cells by enhancing the RhoA pathway. Furthermore, we found that pretreatment with a Rho kinase inhibitor Y-27632 resulted in partial rescue of Schwann cell differentiation and neurite outgrowth. In vivo experiments showed that SCYL1BP1 could also suppress nerve fiber regeneration. In conclusion, we speculated that SCYL1BP1 participated in Schwann cell (SC) differentiation and neurite outgrowth in the sciatic nerve after crush by regulating the RhoA pathway.
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Affiliation(s)
- Weidong Zhang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Yonghua Liu
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu, 226001, People's Republic of China
| | - Xudong Zhu
- Medical College, Nantong University, 19 Qi-Xiu Road, Nantong, 226001, Jiangsu Province, People's Republic of China
| | - Yi Cao
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Yang Liu
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China.,Department of Pathogen Biology, Medical College, Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Xingxing Mao
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China
| | - Huiguang Yang
- Department of Orthopaedics, Affiliated Jiangyin Hospital of Nantong University, Nantong, Jiangsu, 226001, People's Republic of China
| | - Zhengming Zhou
- Department of Orthopaedics, Affiliated Jiangyin Hospital of Nantong University, Nantong, Jiangsu, 226001, People's Republic of China
| | - Youhua Wang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Nantong, 226001, Jiangsu, People's Republic of China.
| | - Aiguo Shen
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Medical College of Nantong University, Nantong, Jiangsu, 226001, People's Republic of China.
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83
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Lopez-Anido C, Sun G, Koenning M, Srinivasan R, Hung HA, Emery B, Keles S, Svaren J. Differential Sox10 genomic occupancy in myelinating glia. Glia 2015; 63:1897-1914. [PMID: 25974668 PMCID: PMC4644515 DOI: 10.1002/glia.22855] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/22/2015] [Indexed: 11/11/2022]
Abstract
Myelin is formed by specialized myelinating glia: oligodendrocytes and Schwann cells in the central and peripheral nervous systems, respectively. While there are distinct developmental aspects and regulatory pathways in these two cell types, myelination in both systems requires the transcriptional activator Sox10. Sox10 interacts with cell type-specific transcription factors at some loci to induce myelin gene expression, but it is largely unknown how Sox10 transcriptional networks globally compare between oligodendrocytes and Schwann cells. We used in vivo ChIP-Seq analysis of spinal cord and peripheral nerve (sciatic nerve) to identify unique and shared Sox10 binding sites and assess their correlation with active enhancers and transcriptional profiles in oligodendrocytes and Schwann cells. Sox10 binding sites overlap with active enhancers and critical cell type-specific regulators of myelination, such as Olig2 and Myrf in oligodendrocytes, and Egr2/Krox20 in Schwann cells. Sox10 sites also associate with genes critical for myelination in both oligodendrocytes and Schwann cells and are found within super-enhancers previously defined in brain. In Schwann cells, Sox10 sites contain binding motifs of putative partners in the Sp/Klf, Tead, and nuclear receptor protein families. Specifically, siRNA analysis of nuclear receptors Nr2f1 and Nr2f2 revealed downregulation of myelin genes Mbp and Ndrg1 in primary Schwann cells. Our analysis highlights different mechanisms that establish cell type-specific genomic occupancy of Sox10, which reflects the unique characteristics of oligodendrocyte and Schwann cell differentiation. GLIA 2015;63:1897-1914.
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Affiliation(s)
- Camila Lopez-Anido
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Comparative Biomedical Sciences Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Guannan Sun
- Department of Biostatistics & Medical Informatics, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Matthias Koenning
- Department of Anatomy and Neuroscience and the Centre for Neuroscience Research, University of Melbourne, Melbourne, Australia
| | - Rajini Srinivasan
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Holly A. Hung
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ben Emery
- Department of Anatomy and Neuroscience and the Centre for Neuroscience Research, University of Melbourne, Melbourne, Australia
| | - Sunduz Keles
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - John Svaren
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53705, USA
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84
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Regulation of Peripheral Nerve Myelin Maintenance by Gene Repression through Polycomb Repressive Complex 2. J Neurosci 2015; 35:8640-52. [PMID: 26041929 DOI: 10.1523/jneurosci.2257-14.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Myelination of peripheral nerves by Schwann cells requires coordinate regulation of gene repression as well as gene activation. Several chromatin remodeling pathways critical for peripheral nerve myelination have been identified, but the functions of histone methylation in the peripheral nerve have not been elucidated. To determine the role of histone H3 Lys27 methylation, we have generated mice with a Schwann cell-specific knock-out of Eed, which is an essential subunit of the polycomb repressive complex 2 (PRC2) that catalyzes methylation of histone H3 Lys27. Analysis of this mutant revealed no significant effects on early postnatal development of myelin. However, its loss eventually causes progressive hypermyelination of small-diameter axons and apparent fragmentation of Remak bundles. These data identify the PRC2 complex as an epigenomic modulator of mature myelin thickness, which is associated with changes in Akt phosphorylation. Interestingly, we found that Eed inactivation causes derepression of several genes, e.g., Sonic hedgehog (Shh) and Insulin-like growth factor-binding protein 2 (Igfbp2), that become activated after nerve injury, but without activation of a primary regulator of the injury program, c-Jun. Analysis of the activated genes in cultured Schwann cells showed that Igfbp2 regulates Akt activation. Our results identify an epigenomic pathway required for establishing thickness of mature myelin and repressing genes that respond to nerve injury.
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85
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Lin HP, Oksuz I, Hurley E, Wrabetz L, Awatramani R. Microprocessor complex subunit DiGeorge syndrome critical region gene 8 (Dgcr8) is required for schwann cell myelination and myelin maintenance. J Biol Chem 2015; 290:24294-307. [PMID: 26272614 DOI: 10.1074/jbc.m115.636407] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Indexed: 01/25/2023] Open
Abstract
We investigated the role of a key component of the Microprocessor complex, DGCR8, in the regulation of myelin formation and maintenance. We found that conditionally ablating Dgcr8 in Schwann cells (SCs) during development results in an arrest of SC differentiation. Dgcr8 conditional knock-out (cKO) SCs fail to form 1:1 relationships with axons or, having achieved this, fail to form myelin sheaths. The expression of genes normally found in immature SCs, such as sex-determining region Y-box 2 (Sox2), is increased in Dgcr8 cKO SCs, whereas the expression of myelin-related genes, including the master regulatory transcription factor early growth response 2 (Egr2), is decreased. Additionally, expression of a novel gene expression program involving sonic hedgehog (Shh), activated de novo in injured nerves, is elevated in Dgcr8 cKOs but not in Egr2 null mice, a model of SC differentiation arrest, suggesting that the injury-related gene expression program in Dgcr8 cKOs cannot be attributed to differentiation arrest. Inducible ablation of Dgcr8 in adult SCs results in gene expression changes similar to those found in cKOs, including an increase in the expression of Sox2 and Shh. Analyses of these nerves mainly reveal normal myelin thickness and axon size distribution but some dedifferentiated SCs and increased macrophage infiltration. Together our data suggest that Dgcr8 is responsible for modulation of gene expression programs underlying myelin formation and maintenance as well as suppression of an injury-related gene expression program.
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Affiliation(s)
- Hsin-Pin Lin
- From the Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 and
| | - Idil Oksuz
- From the Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 and
| | - Edward Hurley
- Hunter James Kelly Research Institute, University at Buffalo, State University of New York, Buffalo, New York 14203
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, University at Buffalo, State University of New York, Buffalo, New York 14203
| | - Rajeshwar Awatramani
- From the Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 and
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86
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Hoyng SA, de Winter F, Tannemaat MR, Blits B, Malessy MJA, Verhaagen J. Gene therapy and peripheral nerve repair: a perspective. Front Mol Neurosci 2015; 8:32. [PMID: 26236188 PMCID: PMC4502351 DOI: 10.3389/fnmol.2015.00032] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/01/2015] [Indexed: 12/19/2022] Open
Abstract
Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan's, Parkinson's (PD) and Alzheimer's disease (AD), retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral vectors (AAV) and the first AAV-based therapeutic, a vector encoding lipoprotein lipase, is now marketed in Europe under the name Glybera. These remarkable advances may become relevant to translational research on gene therapy to promote peripheral nervous system (PNS) repair. This short review first summarizes the results of gene therapy in animal models for peripheral nerve repair. Secondly, we identify key areas of future research in the domain of PNS-gene therapy. Finally, a perspective is provided on the path to clinical translation of PNS-gene therapy for traumatic nerve injuries. In the latter section we discuss the route and mode of delivery of the vector to human patients, the efficacy and safety of the vector, and the choice of the patient population for a first possible proof-of-concept clinical study.
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Affiliation(s)
- Stefan A Hoyng
- Department of Neuroregeneration, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Department of Neurosurgery, Leiden University Medical Center Leiden, Netherlands
| | - Fred de Winter
- Department of Neuroregeneration, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Department of Neurosurgery, Leiden University Medical Center Leiden, Netherlands
| | - Martijn R Tannemaat
- Department of Neuroregeneration, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Department of Neurology, Leiden University Medical Center Leiden, Netherlands
| | | | - Martijn J A Malessy
- Department of Neuroregeneration, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Department of Neurosurgery, Leiden University Medical Center Leiden, Netherlands
| | - Joost Verhaagen
- Department of Neuroregeneration, Netherlands Institute for Neuroscience Amsterdam, Netherlands ; Center for Neurogenomics and Cognition Research, Neuroscience Campus Amsterdam Amsterdam, Netherlands
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