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Oliveira JT, Yanick C, Wein N, Gomez Limia CE. Neuron-Schwann cell interactions in peripheral nervous system homeostasis, disease, and preclinical treatment. Front Cell Neurosci 2023; 17:1248922. [PMID: 37900588 PMCID: PMC10600466 DOI: 10.3389/fncel.2023.1248922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/19/2023] [Indexed: 10/31/2023] Open
Abstract
Schwann cells (SCs) have a critical role in the peripheral nervous system. These cells are able to support axons during homeostasis and after injury. However, mutations in genes associated with the SCs repair program or myelination result in dysfunctional SCs. Several neuropathies such as Charcot-Marie-Tooth (CMT) disease, diabetic neuropathy and Guillain-Barré syndrome show abnormal SC functions and an impaired regeneration process. Thus, understanding SCs-axon interaction and the nerve environment in the context of homeostasis as well as post-injury and disease onset is necessary. Several neurotrophic factors, cytokines, and regulators of signaling pathways associated with proliferation, survival and regeneration are involved in this process. Preclinical studies have focused on the discovery of therapeutic targets for peripheral neuropathies and injuries. To study the effect of new therapeutic targets, modeling neuropathies and peripheral nerve injuries (PNIs) in vitro and in vivo are useful tools. Furthermore, several in vitro protocols have been designed using SCs and neuron cell lines to evaluate these targets in the regeneration process. SCs lines have been used to generate effective myelinating SCs without success. Alternative options have been investigated using direct conversion from somatic cells to SCs or SCs derived from pluripotent stem cells to generate functional SCs. This review will go over the advantages of these systems and the problems associated with them. In addition, there have been challenges in establishing adequate and reproducible protocols in vitro to recapitulate repair SC-neuron interactions observed in vivo. So, we also discuss the mechanisms of repair SCs-axon interactions in the context of peripheral neuropathies and nerve injury (PNI) in vitro and in vivo. Finally, we summarize current preclinical studies evaluating transgenes, drug, and novel compounds with translational potential into clinical studies.
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Affiliation(s)
| | | | - Nicolas Wein
- Center for Gene Therapy, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
- Department of Pediatrics, The Ohio State University, Columbus, OH, United States
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Duman M, Jaggi S, Enz LS, Jacob C, Schaeren-Wiemers N. Theophylline Induces Remyelination and Functional Recovery in a Mouse Model of Peripheral Neuropathy. Biomedicines 2022; 10:biomedicines10061418. [PMID: 35740439 PMCID: PMC9219657 DOI: 10.3390/biomedicines10061418] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/05/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a large group of inherited peripheral neuropathies that are primarily due to demyelination and/or axonal degeneration. CMT type 1A (CMT1A), which is caused by the duplication of the peripheral myelin protein 22 (PMP22) gene, is a demyelinating and the most frequent CMT subtype. Hypermyelination, demyelination, and secondary loss of large-caliber axons are hallmarks of CMT1A, and there is currently no cure and no efficient treatment to alleviate the symptoms of the disease. We previously showed that histone deacetylases 1 and 2 (HDAC1/2) are critical for Schwann cell developmental myelination and remyelination after a sciatic nerve crush lesion. We also demonstrated that a short-term treatment with Theophylline, which is a potent activator of HDAC2, enhances remyelination and functional recovery after a sciatic nerve crush lesion in mice. In the present study, we tested whether Theophylline treatment could also lead to (re)myelination in a PMP22-overexpressing mouse line (C22) modeling CMT1A. Indeed, we show here that a short-term treatment with Theophylline in C22 mice increases the percentage of myelinated large-caliber axons and the expression of the major peripheral myelin protein P0 and induces functional recovery. This pilot study suggests that Theophylline treatment could be beneficial to promote myelination and thereby prevent axonal degeneration and enhance functional recovery in CMT1A patients.
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Affiliation(s)
- Mert Duman
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland;
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Stephanie Jaggi
- Department of Biomedicine, University Hospital Basel, 4031 Basel, Switzerland; (S.J.); (L.S.E.); (N.S.-W.)
| | - Lukas Simon Enz
- Department of Biomedicine, University Hospital Basel, 4031 Basel, Switzerland; (S.J.); (L.S.E.); (N.S.-W.)
| | - Claire Jacob
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland;
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Correspondence:
| | - Nicole Schaeren-Wiemers
- Department of Biomedicine, University Hospital Basel, 4031 Basel, Switzerland; (S.J.); (L.S.E.); (N.S.-W.)
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
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3
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Transcriptome Analysis of Schwann Cells at Various Stages of Myelination Implicates Chromatin Regulator Sin3A in Control of Myelination Identity. Neurosci Bull 2022; 38:720-740. [DOI: 10.1007/s12264-022-00850-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/13/2021] [Indexed: 10/18/2022] Open
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4
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Yun W, Kim YJ, Lee G. Direct Conversion to Achieve Glial Cell Fates: Oligodendrocytes and Schwann Cells. Int J Stem Cells 2022; 15:14-25. [PMID: 35220289 PMCID: PMC8889328 DOI: 10.15283/ijsc22008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
Glia have been known for its pivotal roles in physiological and pathological conditions in the nervous system. To study glial biology, multiple approaches have been applied to utilize glial cells for research, including stem cell-based technologies. Human glial cells differentiated from pluripotent stem cells are now available, allowing us to study the structural and functional roles of glia in the nervous system, although the efficiency is still low. Direct conversion is an advanced strategy governing fate conversion of diverse cell types directly into the desired lineage. This novel strategy stands as a promising approach for preliminary research and regenerative medicine. Direct conversion employs genetic and environmental cues to change cell fate to that with the required functional cell properties while retaining maturity-related molecular features. As an alternative method, it is now possible to obtain a variety of mature cell populations that could not be obtained using conventional differentiation methods. This review summarizes current achievements in obtaining glia, particularly oligodendrocytes and Schwann cells.
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Affiliation(s)
- Wonjin Yun
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yong Jun Kim
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul, Korea
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Gabsang Lee
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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5
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Mukherjee D, Gonzales BJ, Ashwal-Fluss R, Turm H, Groysman M, Citri A. Egr2 induction in spiny projection neurons of the ventrolateral striatum contributes to cocaine place preference in mice. eLife 2021; 10:65228. [PMID: 33724178 PMCID: PMC8057818 DOI: 10.7554/elife.65228] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/15/2021] [Indexed: 12/16/2022] Open
Abstract
Drug addiction develops due to brain-wide plasticity within neuronal ensembles, mediated by dynamic gene expression. Though the most common approach to identify such ensembles relies on immediate early gene expression, little is known of how the activity of these genes is linked to modified behavior observed following repeated drug exposure. To address this gap, we present a broad-to-specific approach, beginning with a comprehensive investigation of brain-wide cocaine-driven gene expression, through the description of dynamic spatial patterns of gene induction in subregions of the striatum, and finally address functionality of region-specific gene induction in the development of cocaine preference. Our findings reveal differential cell-type specific dynamic transcriptional recruitment patterns within two subdomains of the dorsal striatum following repeated cocaine exposure. Furthermore, we demonstrate that induction of the IEG Egr2 in the ventrolateral striatum, as well as the cells within which it is expressed, are required for the development of cocaine seeking. The human brain is ever changing, constantly rewiring itself in response to new experiences, knowledge or information from the environment. Addictive drugs such as cocaine can hijack the genetic mechanisms responsible for this plasticity, creating dangerous, obsessive drug-seeking and consuming behaviors. Cocaine-induced plasticity is difficult to apprehend, however, as brain regions or even cell populations can react differently to the compound. For instance, sub-regions in the striatum – the brain area that responds to rewards and helps to plan movement – show distinct responses during progressive exposure to cocaine. And while researchers know that the drug immediately changes how neurons switch certain genes on and off, it is still unclear how these genetic modifications later affect behavior. Mukherjee, Gonzales et al. explored these questions at different scales, first focusing on how progressive cocaine exposure changed the way various gene programs were activated across the entire brain. This revealed that programs in the striatum were the most affected by the drug. Examining this region more closely showed that cocaine switches on genes in specific ‘spiny projection’ neuron populations, depending on where these cells are located and the drug history of the mouse. Finally, Mukherjee, Gonzales et al. used genetically modified mice to piece together cocaine exposure, genetic changes and modifications in behavior. These experiments revealed that the drive to seek cocaine depended on activation of the Egr2 gene in populations of spiny projection neurons in a specific sub-region of the striatum. The gene, which codes for a protein that regulates how genes are switched on and off, was itself strongly activated by cocaine intake. Cocaine addiction can have devastating consequences for individuals. Grasping how this drug alters the brain could pave the way for new treatments, while also providing information on the basic mechanisms underlying brain plasticity.
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Affiliation(s)
- Diptendu Mukherjee
- The Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel.,Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ben Jerry Gonzales
- The Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel.,Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Reut Ashwal-Fluss
- The Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel
| | - Hagit Turm
- The Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel.,Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maya Groysman
- The Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel
| | - Ami Citri
- The Edmond and Lily Safra Center for Brain Sciences, Jerusalem, Israel.,Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.,Program in Child and Brain Development, Canadian Institute for Advanced Research, MaRS Centre, Toronto, Canada
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6
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Balakrishnan A, Belfiore L, Chu TH, Fleming T, Midha R, Biernaskie J, Schuurmans C. Insights Into the Role and Potential of Schwann Cells for Peripheral Nerve Repair From Studies of Development and Injury. Front Mol Neurosci 2021; 13:608442. [PMID: 33568974 PMCID: PMC7868393 DOI: 10.3389/fnmol.2020.608442] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/31/2020] [Indexed: 12/13/2022] Open
Abstract
Peripheral nerve injuries arising from trauma or disease can lead to sensory and motor deficits and neuropathic pain. Despite the purported ability of the peripheral nerve to self-repair, lifelong disability is common. New molecular and cellular insights have begun to reveal why the peripheral nerve has limited repair capacity. The peripheral nerve is primarily comprised of axons and Schwann cells, the supporting glial cells that produce myelin to facilitate the rapid conduction of electrical impulses. Schwann cells are required for successful nerve regeneration; they partially “de-differentiate” in response to injury, re-initiating the expression of developmental genes that support nerve repair. However, Schwann cell dysfunction, which occurs in chronic nerve injury, disease, and aging, limits their capacity to support endogenous repair, worsening patient outcomes. Cell replacement-based therapeutic approaches using exogenous Schwann cells could be curative, but not all Schwann cells have a “repair” phenotype, defined as the ability to promote axonal growth, maintain a proliferative phenotype, and remyelinate axons. Two cell replacement strategies are being championed for peripheral nerve repair: prospective isolation of “repair” Schwann cells for autologous cell transplants, which is hampered by supply challenges, and directed differentiation of pluripotent stem cells or lineage conversion of accessible somatic cells to induced Schwann cells, with the potential of “unlimited” supply. All approaches require a solid understanding of the molecular mechanisms guiding Schwann cell development and the repair phenotype, which we review herein. Together these studies provide essential context for current efforts to design glial cell-based therapies for peripheral nerve regeneration.
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Affiliation(s)
- Anjali Balakrishnan
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lauren Belfiore
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Tak-Ho Chu
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Taylor Fleming
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada
| | - Rajiv Midha
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jeff Biernaskie
- Department of Comparative Biology and Experimental Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Carol Schuurmans
- Biological Sciences Platform, Sunnybrook Research Institute (SRI), Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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7
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Schock EN, LaBonne C. Sorting Sox: Diverse Roles for Sox Transcription Factors During Neural Crest and Craniofacial Development. Front Physiol 2020; 11:606889. [PMID: 33424631 PMCID: PMC7793875 DOI: 10.3389/fphys.2020.606889] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/09/2020] [Indexed: 12/31/2022] Open
Abstract
Sox transcription factors play many diverse roles during development, including regulating stem cell states, directing differentiation, and influencing the local chromatin landscape. Of the twenty vertebrate Sox factors, several play critical roles in the development the neural crest, a key vertebrate innovation, and the subsequent formation of neural crest-derived structures, including the craniofacial complex. Herein, we review the specific roles for individual Sox factors during neural crest cell formation and discuss how some factors may have been essential for the evolution of the neural crest. Additionally, we describe how Sox factors direct neural crest cell differentiation into diverse lineages such as melanocytes, glia, and cartilage and detail their involvement in the development of specific craniofacial structures. Finally, we highlight several SOXopathies associated with craniofacial phenotypes.
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Affiliation(s)
- Elizabeth N Schock
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States
| | - Carole LaBonne
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States.,NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, IL, United States
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8
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Yu L, Peng F, Dong X, Chen Y, Sun D, Jiang S, Deng C. Sex-Determining Region Y Chromosome-Related High-Mobility-Group Box 10 in Cancer: A Potential Therapeutic Target. Front Cell Dev Biol 2020; 8:564740. [PMID: 33344444 PMCID: PMC7744619 DOI: 10.3389/fcell.2020.564740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/17/2020] [Indexed: 01/20/2023] Open
Abstract
Sex-determining region Y-related high mobility group-box 10 (SOX10), a member of the SOX family, has recently been highlighted as an essential transcriptional factor involved in developmental biology. Recently, the functionality of SOX 10 has been increasingly revealed by researchers worldwide. It has been reported that SOX10 significantly regulates the proliferation, migration, and apoptosis of tumors and is closely associated with the progression of cancer. In this review, we first introduce the basic background of the SOX family and SOX10 and then discuss the pathophysiological roles of SOX10 in cancer. Besides, we enumerate the application of SOX10 in the pathological diagnosis and therapeutic potential of cancer. Eventually, we summarize the potential directions and perspectives of SOX10 in neoplastic theranostics. The information compiled herein may assist in additional studies and increase the potential of SOX10 as a therapeutic target for cancer.
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Affiliation(s)
- Liming Yu
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.,Department of Cardiovascular Surgery, General Hospital of Northern Theater Command, Shenyang, China
| | - Fan Peng
- Department of Cardiology, Xijing Hopspital, The Airforce Military Medical University, Xi'an, China
| | - Xue Dong
- Outpatient Department of Liaoning Military Region, General Hospital of Northern Theater Command, Shenyang, China
| | - Ying Chen
- Department of Hematology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Dongdong Sun
- Department of Cardiology, Xijing Hopspital, The Airforce Military Medical University, Xi'an, China
| | - Shuai Jiang
- Department of Cardiology, Xijing Hopspital, The Airforce Military Medical University, Xi'an, China
| | - Chao Deng
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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9
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A de novo EGR2 variant, c.1232A > G p.Asp411Gly, causes severe early-onset Charcot-Marie-Tooth Neuropathy Type 3 (Dejerine-Sottas Neuropathy). Sci Rep 2019; 9:19336. [PMID: 31852952 PMCID: PMC6920433 DOI: 10.1038/s41598-019-55875-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/03/2019] [Indexed: 01/04/2023] Open
Abstract
EGR2 (early growth response 2) is a crucial transcription factor for the myelination of the peripheral nervous system. Mutations in EGR2 are reported to cause a heterogenous spectrum of peripheral neuropathy with wide variation in both severity and age of onset, including demyelinating and axonal forms of Charcot-Marie Tooth (CMT) neuropathy, Dejerine-Sottas neuropathy (DSN/CMT3), and congenital hypomyelinating neuropathy (CHN/CMT4E). Here we report a sporadic de novo EGR2 variant, c.1232A > G (NM_000399.5), causing a missense p.Asp411Gly substitution and discovered through whole-exome sequencing (WES) of the proband. The resultant phenotype is severe demyelinating DSN with onset at two years of age, confirmed through nerve biopsy and electrophysiological examination. In silico analyses showed that the Asp411 residue is evolutionarily conserved, and the p.Asp411Gly variant was predicted to be deleterious by multiple in silico analyses. A luciferase-based reporter assay confirmed the reduced ability of p.Asp411Gly EGR2 to activate a PMP22 (peripheral myelin protein 22) enhancer element compared to wild-type EGR2. This study adds further support to the heterogeneity of EGR2-related peripheral neuropathies and provides strong functional evidence for the pathogenicity of the p.Asp411Gly EGR2 variant.
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10
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Bian Y, Wei G, Song X, Yuan L, Chen H, Ni T, Lu D. Global downregulation of pigmentation-associated genes in human premature hair graying. Exp Ther Med 2019; 18:1155-1163. [PMID: 31316609 PMCID: PMC6601371 DOI: 10.3892/etm.2019.7663] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/13/2018] [Indexed: 12/15/2022] Open
Abstract
Premature hair graying, or canities, is a complex multi-factorial process with negative effects on affected individuals. The aim of the present study was to investigate the possible underlying mechanisms of premature hair graying at the genetic level. A total of 5 unrelated Han Chinese individuals presenting with premature hair graying (25–40 years old, with >1% hair affected) were enrolled in the present study. RNA sequencing was performed to identify gene expression changes between the follicular cells of grey and black hair from the cohort. A total of 127 differentially expressed genes (DEGs) were identified. These DEGs were overrepresented in categories associated with the pigmentation pathway, with a decreased expression of key genes responsible for melanin synthesis. Of note, the decreased expression of certain transcription factors and the increased expression of certain precursor microRNAs observed may explain for the downregulation of certain other DEGs, which were identified as their targets via Starbase v2 and Integrated Motif Activity Response Analysis. The DEGs were also enriched in terms associated with the nervous system, indicating that neural disturbances may also have certain roles in premature hair graying. Of note, five of the downregulated DEGs were associated with aging according to the JenAge Aging Factor Database. To the best of our knowledge, the present study was the first genome-wide survey of the gene expression profile associated with premature hair graying. Dysfunction of the melanin biosynthesis pathway is probably the direct cause of hair graying and the present results provide valuable clues for further functional and mechanistic investigation.
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Affiliation(s)
- Yunmeng Bian
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Gang Wei
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Xiao Song
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University, Shanghai 200433, P.R. China
| | - Li Yuan
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Hongyan Chen
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
| | - Daru Lu
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200438, P.R. China
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11
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Li G, Chen S, Zeng M, Kong Y, Zhao F, Zhang L, Yang Y. Hierarchically aligned gradient collagen micropatterns for rapidly screening Schwann cells behavior. Colloids Surf B Biointerfaces 2019; 176:341-351. [PMID: 30654241 DOI: 10.1016/j.colsurfb.2019.01.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 12/25/2018] [Accepted: 01/07/2019] [Indexed: 12/13/2022]
Abstract
To penetrate the effect of protein gradient micropattern on peripheral nerve regeneration, the hierarchically aligned gradient collagen micropattern was prepared by micromoulding method and the influence on Schwann cells growth behavior was studied. The morphology, wettability, stability and component variation of the micropatterns were firstly characterized. Then, Schwann cells were cultured and the related mechanism was penetrated. The results showed that the gradient collagen micropattern could be well fabricated. The surface wettability varied with the change of collagen concentration, and the prepared gradient micropattern showed a good stability after PBS immersion for 15 days. The results of Schwann cells culture and morphological index analysis displayed that the prepared gradient collagen micropatten could well regulate the orientation growth of Schwann cells, while a much better cell alignment growth was obtained on the gradient micropattern with higher collagen concentration and wider pattern size. PCR and WB showed that the micropattern structure could effectively up-regulate the key specific genes for axon regeneration and myelination process. Overall, the study provides a systematic and facile method for understanding the effect of various sized micropatterns on cell behavior, which may have a great significance for the development of artificial implants for tissue engineering and regenerative medicine.
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Affiliation(s)
- Guicai Li
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong University, 226001, Nantong, PR China; Co-innovation Center of Neuroregeneration, Nantong University, 226001, Nantong, PR China.
| | - Shiyu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong University, 226001, Nantong, PR China; Co-innovation Center of Neuroregeneration, Nantong University, 226001, Nantong, PR China
| | - Ming Zeng
- School of Biology Science, Nantong University, 226019, Nantong, PR China
| | - Yan Kong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong University, 226001, Nantong, PR China; Co-innovation Center of Neuroregeneration, Nantong University, 226001, Nantong, PR China
| | - Fei Zhao
- School of Biology Science, Nantong University, 226019, Nantong, PR China
| | - Luzhong Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong University, 226001, Nantong, PR China; Co-innovation Center of Neuroregeneration, Nantong University, 226001, Nantong, PR China.
| | - Yumin Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Nantong University, 226001, Nantong, PR China; Co-innovation Center of Neuroregeneration, Nantong University, 226001, Nantong, PR China.
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12
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LaVallee J, Grant T, D'Angelo-Early S, Kletsov S, Berry NA, Abt KM, Bloch CP, Muscedere ML, Adams KW. Refining the nuclear localization signal within the Egr transcriptional coregulator NAB2. FEBS Lett 2018; 593:107-118. [PMID: 30411343 DOI: 10.1002/1873-3468.13288] [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] [Received: 07/31/2018] [Revised: 10/29/2018] [Accepted: 11/02/2018] [Indexed: 01/09/2023]
Abstract
NAB1 and 2 are coregulators for early growth response (Egr) transcription factors. The NAB1 nuclear localization signal (NLS) was previously described as a bipartite NLS of sequence R(X2 )K(X11 )KRXK. The sequence is conserved in NAB2 as K(X2 )R(X11 )KKXK; however, whether it functions as the NAB2 NLS has not been tested. We show that the KKXK motif in NAB2 is necessary and sufficient to mediate nuclear localization. Mutation of the KKXK motif to AAXA causes cytoplasmic localization of NAB2, while Lys/Arg-to-Ala mutations of the upstream K(X2 )R motif have no effect. Fusion of the KKXK motif to cytoplasmic protein eIF2Bε causes nuclear localization. Altogether, this study refines our knowledge of the NAB2 NLS, demonstrating that KKXK343-346 is necessary and sufficient for nuclear localization.
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Affiliation(s)
- Jacquelyn LaVallee
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
| | - Terrain Grant
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
| | | | - Sergey Kletsov
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
| | - Nicole A Berry
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
| | - Kimberly M Abt
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
| | - Christopher P Bloch
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
| | | | - Kenneth W Adams
- Department of Biological Sciences, Bridgewater State University, Bridgewater, MA, USA
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13
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Prior R, Van Helleputte L, Klingl YE, Van Den Bosch L. HDAC6 as a potential therapeutic target for peripheral nerve disorders. Expert Opin Ther Targets 2018; 22:993-1007. [DOI: 10.1080/14728222.2018.1541235] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Robert Prior
- Department of Neurosciences, KU Leuven - University of Leuven, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Lawrence Van Helleputte
- Department of Neurosciences, KU Leuven - University of Leuven, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Yvonne Eileen Klingl
- Department of Neurosciences, KU Leuven - University of Leuven, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, KU Leuven - University of Leuven, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Leuven, Belgium
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14
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Bogdanova-Mihaylova P, Alexander MD, Murphy RPJ, Murphy SM. Waardenburg syndrome: a rare cause of inherited neuropathy due to SOX10 mutation. J Peripher Nerv Syst 2018; 22:219-223. [PMID: 28544110 DOI: 10.1111/jns.12221] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 02/03/2023]
Abstract
Waardenburg syndrome (WS) is a rare disorder comprising sensorineural deafness and pigmentation abnormalities. Four distinct subtypes are defined based on the presence or absence of additional symptoms. Mutations in six genes have been described in WS. SOX10 mutations are usually associated with a more severe phenotype of WS with peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, and Hirschsprung disease. Here we report a 32-year-old man with a novel heterozygous missense variant in SOX10 gene, who presented with congenital deafness, Hirschsprung disease, iris heterochromia, foot deformity, and intermediate conduction velocity length-dependent sensorimotor neuropathy. This case highlights that the presence of other non-neuropathic features in a patient with presumed hereditary neuropathy should alert the clinician to possible atypical rare causes.
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Affiliation(s)
- Petya Bogdanova-Mihaylova
- Department of Neurology, Adelaide & Meath Hospitals incorporating the National Children's Hospital, Tallaght, Ireland
| | - Michael D Alexander
- Department of Neurophysiology, Adelaide & Meath Hospitals incorporating the National Children's Hospital, Tallaght, Ireland
| | - Raymond P J Murphy
- Department of Neurology, Adelaide & Meath Hospitals incorporating the National Children's Hospital, Tallaght, Ireland
| | - Sinéad M Murphy
- Department of Neurology, Adelaide & Meath Hospitals incorporating the National Children's Hospital, Tallaght, Ireland.,Academic Unit of Neurology, Trinity College Dublin, Dublin, Ireland
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15
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Lin HP, Oksuz I, Svaren J, Awatramani R. Egr2-dependent microRNA-138 is dispensable for peripheral nerve myelination. Sci Rep 2018; 8:3817. [PMID: 29491350 PMCID: PMC5830491 DOI: 10.1038/s41598-018-22010-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/14/2018] [Indexed: 12/27/2022] Open
Abstract
Recent studies have elucidated the crucial role for microRNAs in peripheral nerve myelination by ablating components of the microRNA synthesis machinery. Few studies have focused on the role of individual microRNAs. To fill this gap, we focused this study on miR-138, which was shown to be drastically reduced in Dicer1 and Dgcr8 knockout mice with hypomyelinating phenotypes and to potentially target the negative regulators of Schwann cell differentiation. Here, we show that of two miR-138 encoding loci, mir-138-1 is the predominant locus transcribed in Schwann cells. mir-138-1 is transcriptionally upregulated during myelination and downregulated upon nerve injury. EGR2 is required for mir-138-1 transcription during development, and both SOX10 and EGR2 bind to an active enhancer near the mir-138-1 locus. Based on expression analyses, we hypothesized that miR-138 facilitates the transition between undifferentiated Schwann cells and myelinating Schwann cells. However, in conditional knockouts, we could not detect significant changes in Schwann cell proliferation, cell cycle exit, or myelination. Overall, our results demonstrate that miR-138 is an Egr2-dependent microRNA but is dispensable for Schwann cell myelination.
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Affiliation(s)
- Hsin-Pin Lin
- Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Idil Oksuz
- Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - John Svaren
- Waisman Center and Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Rajeshwar Awatramani
- Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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16
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Marathe HG, Watkins-Chow DE, Weider M, Hoffmann A, Mehta G, Trivedi A, Aras S, Basuroy T, Mehrotra A, Bennett DC, Wegner M, Pavan WJ, de la Serna IL. BRG1 interacts with SOX10 to establish the melanocyte lineage and to promote differentiation. Nucleic Acids Res 2017; 45:6442-6458. [PMID: 28431046 PMCID: PMC5499657 DOI: 10.1093/nar/gkx259] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/04/2017] [Indexed: 12/30/2022] Open
Abstract
Mutations in SOX10 cause neurocristopathies which display varying degrees of hypopigmentation. Using a sensitized mutagenesis screen, we identified Smarca4 as a modifier gene that exacerbates the phenotypic severity of Sox10 haplo-insufficient mice. Conditional deletion of Smarca4 in SOX10 expressing cells resulted in reduced numbers of cranial and ventral trunk melanoblasts. To define the requirement for the Smarca4 -encoded BRG1 subunit of the SWI/SNF chromatin remodeling complex, we employed in vitro models of melanocyte differentiation in which induction of melanocyte-specific gene expression is closely linked to chromatin alterations. We found that BRG1 was required for expression of Dct, Tyrp1 and Tyr, genes that are regulated by SOX10 and MITF and for chromatin remodeling at distal and proximal regulatory sites. SOX10 was found to physically interact with BRG1 in differentiating melanocytes and binding of SOX10 to the Tyrp1 distal enhancer temporally coincided with recruitment of BRG1. Our data show that SOX10 cooperates with MITF to facilitate BRG1 binding to distal enhancers of melanocyte-specific genes. Thus, BRG1 is a SOX10 co-activator, required to establish the melanocyte lineage and promote expression of genes important for melanocyte function.
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Affiliation(s)
- Himangi G Marathe
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
| | - Dawn E Watkins-Chow
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-4472, USA
| | - Matthias Weider
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Alana Hoffmann
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Gaurav Mehta
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
| | - Archit Trivedi
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
| | - Shweta Aras
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
| | - Tupa Basuroy
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
| | - Aanchal Mehrotra
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
| | - Dorothy C Bennett
- Molecular and Clinical Sciences Research Institute, St George's, University of London, London SW17 0RE, UK
| | - Michael Wegner
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - William J Pavan
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-4472, USA
| | - Ivana L de la Serna
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614, USA
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17
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Andrés-Benito P, Moreno J, Aso E, Povedano M, Ferrer I. Amyotrophic lateral sclerosis, gene deregulation in the anterior horn of the spinal cord and frontal cortex area 8: implications in frontotemporal lobar degeneration. Aging (Albany NY) 2017; 9:823-851. [PMID: 28283675 PMCID: PMC5391234 DOI: 10.18632/aging.101195] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/27/2017] [Indexed: 12/14/2022]
Abstract
Transcriptome arrays identifies 747 genes differentially expressed in the anterior horn of the spinal cord and 2,300 genes differentially expressed in frontal cortex area 8 in a single group of typical sALS cases without frontotemporal dementia compared with age-matched controls. Main up-regulated clusters in the anterior horn are related to inflammation and apoptosis; down-regulated clusters are linked to axoneme structures and protein synthesis. In contrast, up-regulated gene clusters in frontal cortex area 8 involve neurotransmission, synaptic proteins and vesicle trafficking, whereas main down-regulated genes cluster into oligodendrocyte function and myelin-related proteins. RT-qPCR validates the expression of 58 of 66 assessed genes from different clusters. The present results: a. reveal regional differences in de-regulated gene expression between the anterior horn of the spinal cord and frontal cortex area 8 in the same individuals suffering from sALS; b. validate and extend our knowledge about the complexity of the inflammatory response in the anterior horn of the spinal cord; and c. identify for the first time extensive gene up-regulation of neurotransmission and synaptic-related genes, together with significant down-regulation of oligodendrocyte- and myelin-related genes, as important contributors to the pathogenesis of frontal cortex alterations in the sALS/frontotemporal lobar degeneration spectrum complex at stages with no apparent cognitive impairment.
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Affiliation(s)
- Pol Andrés-Benito
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
| | - Jesús Moreno
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
| | - Ester Aso
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
| | - Mónica Povedano
- Service of Neurology, Bellvitge University Hospital, Hospitalet de Llobregat, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Spain
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Hospitalet de Llobregat, Spain
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18
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Orczyk JJ, Batka R, Gore A, Maio-Lexa M, Kulkarni A, Garraghty PE. Female rat transcriptome response to infraorbital nerve transection differs from that of males: RNA-seq. J Comp Neurol 2017; 525:140-150. [PMID: 27224679 DOI: 10.1002/cne.24045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 05/20/2016] [Accepted: 05/23/2016] [Indexed: 11/06/2022]
Abstract
The effects of infraorbital nerve (ION) transection on gene expression in the adult female rat barrel cortex were investigated using RNA sequencing. After a 24-hour survival duration, 28 genes were differentially regulated by ION transection. Differentially expressed genes suggest microglial activity, increased retrograde ciliary transport, and a decrease in inhibition. These changes may be functionally comparable to changes in the male barrel cortex, where changes in genes related to morphology, neuronal activity, and neuronal excitability were observed. However, the patterns in changes in gene expression are vastly different between male and female rats. The results strongly caution against the practice of generalizing data from one sex to both sexes. This cautionary note has potentially profound implications for a range of research lines, including substance abuse and stress, both research domains in which subjects have been predominantly males. Future research needs to employ sex as a classification variable, as sex differences can generally be expected. Future research is also needed to confirm that changes in gene expression observed with RNA-seq correlate with changes in protein expression. J. Comp. Neurol. 525:140-150, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- John J Orczyk
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Richard Batka
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Ashleigh Gore
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Michelena Maio-Lexa
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Akhil Kulkarni
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Preston E Garraghty
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA.,Program in Neuroscience, Indiana University, Bloomington, Indiana, USA
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19
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Balakrishnan A, Stykel MG, Touahri Y, Stratton JA, Biernaskie J, Schuurmans C. Temporal Analysis of Gene Expression in the Murine Schwann Cell Lineage and the Acutely Injured Postnatal Nerve. PLoS One 2016; 11:e0153256. [PMID: 27058953 PMCID: PMC4826002 DOI: 10.1371/journal.pone.0153256] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 03/26/2016] [Indexed: 01/09/2023] Open
Abstract
Schwann cells (SCs) arise from neural crest cells (NCCs) that first give rise to SC precursors (SCPs), followed by immature SCs, pro-myelinating SCs, and finally, non-myelinating or myelinating SCs. After nerve injury, mature SCs ‘de-differentiate’, downregulating their myelination program while transiently re-activating early glial lineage genes. To better understand molecular parallels between developing and de-differentiated SCs, we characterized the expression profiles of a panel of 12 transcription factors from the onset of NCC migration through postnatal stages, as well as after acute nerve injury. Using Sox10 as a pan-glial marker in co-expression studies, the earliest transcription factors expressed in E9.0 Sox10+ NCCs were Sox9, Pax3, AP2α and Nfatc4. E10.5 Sox10+ NCCs coalescing in the dorsal root ganglia differed slightly, expressing Sox9, Pax3, AP2α and Etv5. E12.5 SCPs continued to express Sox10, Sox9, AP2α and Pax3, as well as initiating Sox2 and Egr1 expression. E14.5 immature SCs were similar to SCPs, except that they lost Pax3 expression. By E18.5, AP2α, Sox2 and Egr1 expression was turned off in the nerve, while Jun, Oct6 and Yy1 expression was initiated in pro-myelinating Sox9+/Sox10+ SCs. Early postnatal and adult SCs continued to express Sox9, Jun, Oct6 and Yy1 and initiated Nfatc4 and Egr2 expression. Notably, at all stages, expression of each marker was observed only in a subset of Sox10+ SCs, highlighting the heterogeneity of the SC pool. Following acute nerve injury, Egr1, Jun, Oct6, and Sox2 expression was upregulated, Egr2 expression was downregulated, while Sox9, Yy1, and Nfatc4 expression was maintained at similar frequencies. Notably, de-differentiated SCs in the injured nerve did not display a transcription factor profile corresponding to a specific stage in the SC lineage. Taken together, we demonstrate that uninjured and injured SCs are heterogeneous and distinct from one another, and de-differentiation recapitulates transcriptional aspects of several different embryonic stages.
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Affiliation(s)
- Anjali Balakrishnan
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Morgan G. Stykel
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Yacine Touahri
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Jo Anne Stratton
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Jeff Biernaskie
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- * E-mail: (CS); (JB)
| | - Carol Schuurmans
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
- * E-mail: (CS); (JB)
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20
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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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21
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Stolt CC, Wegner M. Schwann cells and their transcriptional network: Evolution of key regulators of peripheral myelination. Brain Res 2015; 1641:101-110. [PMID: 26423937 DOI: 10.1016/j.brainres.2015.09.025] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/18/2015] [Accepted: 09/20/2015] [Indexed: 11/29/2022]
Abstract
As derivatives of the neural crest, Schwann cells represent a vertebrate invention. Their development and differentiation is under control of a newly constructed, vertebrate-specific regulatory network that contains Sox10, Oct6 and Krox20 as cornerstones and central regulators of peripheral myelination. In this review, we discuss the function and relationship of these transcription factors among each other and in the context of their regulatory network, and present ideas of how neofunctionalization may have helped to recruit them to their novel task in Schwann cells. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- C Claus Stolt
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91054 Erlangen, Germany
| | - Michael Wegner
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91054 Erlangen, Germany.
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22
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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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23
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Sevilla T, Sivera R, Martínez-Rubio D, Lupo V, Chumillas MJ, Calpena E, Dopazo J, Vílchez JJ, Palau F, Espinós C. TheEGR2gene is involved in axonal Charcot−Marie−Tooth disease. Eur J Neurol 2015. [DOI: 10.1111/ene.12782] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- T. Sevilla
- Department of Neurology; Hospital Universitari i Politècnic La Fe; Valencia Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Department of Medicine; University of Valencia; Valencia Spain
| | - R. Sivera
- Department of Neurology; Hospital Universitari i Politècnic La Fe; Valencia Spain
| | - D. Martínez-Rubio
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Program in Genetics and Rare Diseases and IBV/CSIC Associated Unit; Centro de Investigación Príncipe Felipe (CIPF); Valencia Spain
| | - V. Lupo
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Program in Genetics and Rare Diseases and IBV/CSIC Associated Unit; Centro de Investigación Príncipe Felipe (CIPF); Valencia Spain
| | - M. J. Chumillas
- Department of Clinical Neurophysiology; Hospital Universitari i Politècnic La Fe; Valencia Spain
| | - E. Calpena
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Program in Genetics and Rare Diseases and IBV/CSIC Associated Unit; Centro de Investigación Príncipe Felipe (CIPF); Valencia Spain
| | - J. Dopazo
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Program in Computational Genomics; Centro de Investigación Príncipe Felipe (CIPF); Valencia Spain
| | - J. J. Vílchez
- Department of Neurology; Hospital Universitari i Politècnic La Fe; Valencia Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Department of Medicine; University of Valencia; Valencia Spain
| | - F. Palau
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Program in Genetics and Rare Diseases and IBV/CSIC Associated Unit; Centro de Investigación Príncipe Felipe (CIPF); Valencia Spain
| | - C. Espinós
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
- Program in Genetics and Rare Diseases and IBV/CSIC Associated Unit; Centro de Investigación Príncipe Felipe (CIPF); Valencia Spain
- Department of Genetics; Universitat de València; Valencia Spain
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24
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Demyelinating CMT–what’s known, what’s new and what’s in store? Neurosci Lett 2015; 596:14-26. [DOI: 10.1016/j.neulet.2015.01.059] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/23/2015] [Indexed: 02/06/2023]
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25
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Hung HA, Sun G, Keles S, Svaren J. Dynamic regulation of Schwann cell enhancers after peripheral nerve injury. J Biol Chem 2015; 290:6937-50. [PMID: 25614629 PMCID: PMC4358118 DOI: 10.1074/jbc.m114.622878] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/31/2014] [Indexed: 12/20/2022] Open
Abstract
Myelination of the peripheral nervous system is required for axonal function and long term stability. After peripheral nerve injury, Schwann cells transition from axon myelination to a demyelinated state that supports neuronal survival and ultimately remyelination of axons. Reprogramming of gene expression patterns during development and injury responses is shaped by the actions of distal regulatory elements that integrate the actions of multiple transcription factors. We used ChIP-seq to measure changes in histone H3K27 acetylation, a mark of active enhancers, to identify enhancers in myelinating rat peripheral nerve and their dynamics after demyelinating nerve injury. Analysis of injury-induced enhancers identified enriched motifs for c-Jun, a transcription factor required for Schwann cells to support nerve regeneration. We identify a c-Jun-bound enhancer in the gene for Runx2, a transcription factor induced after nerve injury, and we show that Runx2 is required for activation of other induced genes. In contrast, enhancers that lose H3K27ac after nerve injury are enriched for binding sites of the Sox10 and early growth response 2 (Egr2/Krox20) transcription factors, which are critical determinants of Schwann cell differentiation. Egr2 expression is lost after nerve injury, and many Egr2-binding sites lose H3K27ac after nerve injury. However, the majority of Egr2-bound enhancers retain H3K27ac, indicating that other transcription factors maintain active enhancer status after nerve injury. The global epigenomic changes in H3K27ac deposition pinpoint dynamic changes in enhancers that mediate the effects of transcription factors that control Schwann cell myelination and peripheral nervous system responses to nerve injury.
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Affiliation(s)
- Holly A Hung
- From the Waisman Center, Cellular and Molecular Pathology Graduate Program, and
| | - Guannan Sun
- Departments of Biostatistics and Medical Informatics and
| | - Sunduz Keles
- Departments of Biostatistics and Medical Informatics and
| | - John Svaren
- From the Waisman Center, Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin 53705
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26
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Svaren J. MicroRNA and transcriptional crosstalk in myelinating glia. Neurochem Int 2014; 77:50-7. [PMID: 24979526 PMCID: PMC4177339 DOI: 10.1016/j.neuint.2014.06.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/10/2014] [Accepted: 06/17/2014] [Indexed: 12/21/2022]
Abstract
Several recent studies have addressed the important role of microRNA in regulation of differentiation of myelinating glia. While Schwann cells and oligodendrocytes in the peripheral and central nervous systems, respectively, exhibit significant morphological and regulatory differences, some aspects of transcriptional and microRNA regulation are shared between these two cell types. This review focuses on the intersection of microRNAs with transcriptional regulation in Schwann cell and oligodendrocyte differentiation. In particular, several microRNAs have been shown to modulate expression of critical transcription factors, and in turn, the regulation of microRNA expression is enmeshed within transcriptional networks that coordinate both coding gene and noncoding RNA profiles of myelinating cells. These hubs of regulation control both myelin gene expression as well as the cell cycle transitions of Schwann cells and oligodendrocytes as they terminally differentiate. In addition, some studies have begin to highlight the combinatorial effects of different microRNAs that establish the narrow range of gene regulation required for efficient and stable myelin formation. Overall, the integration of microRNA and transcriptional aspects will help elucidate mechanistic control of the myelination process.
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Affiliation(s)
- John Svaren
- Department of Comparative Biosciences and Waisman Center, University of Wisconsin-Madison, 1500 Highland Ave., Madison, WI 53705, USA.
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Masuda T, Wahlin K, Wan J, Hu J, Maruotti J, Yang X, Iacovelli J, Wolkow N, Kist R, Dunaief JL, Qian J, Zack DJ, Esumi N. Transcription factor SOX9 plays a key role in the regulation of visual cycle gene expression in the retinal pigment epithelium. J Biol Chem 2014; 289:12908-21. [PMID: 24634209 DOI: 10.1074/jbc.m114.556738] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The retinal pigment epithelium (RPE) performs specialized functions to support retinal photoreceptors, including regeneration of the visual chromophore. Enzymes and carrier proteins in the visual cycle function sequentially to regenerate and continuously supply 11-cis-retinal to retinal photoreceptor cells. However, it is unknown how the expression of the visual cycle genes is coordinated at the transcriptional level. Here, we show that the proximal upstream regions of six visual cycle genes contain chromatin-accessible sex-determining region Y box (SOX) binding sites, that SOX9 and LIM homeobox 2 (LHX2) are coexpressed in the nuclei of mature RPE cells, and that SOX9 acts synergistically with orthodenticle homeobox 2 (OTX2) to activate the RPE65 and retinaldehyde binding protein 1 (RLBP1) promoters and acts synergistically with LHX2 to activate the retinal G protein-coupled receptor (RGR) promoter. ChIP reveals that SOX9 and OTX2 bind to the promoter regions of RPE65, RLBP1, and RGR and that LHX2 binds to those of RPE65 and RGR in bovine RPE. ChIP with human fetal RPE cells shows that SOX9 and OTX2 also bind to the human RPE65, RLBP1, and RGR promoters. Conditional inactivation of Sox9 in mouse RPE results in reduced expression of several visual cycle genes, most dramatically Rpe65 and Rgr. Furthermore, bioinformatic analysis predicts that multiple common microRNAs (miRNAs) regulate visual cycle genes, and cotransfection of miRNA mimics with luciferase reporter constructs validated some of the predicted miRNAs. These results implicate SOX9 as a key regulator of visual cycle genes, reveal for the first time the functional role of LHX2 in the RPE, and suggest the possible regulation of visual cycle genes by common miRNAs.
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Affiliation(s)
- Tomohiro Masuda
- From the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231
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28
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Kamachi Y, Kondoh H. Sox proteins: regulators of cell fate specification and differentiation. Development 2013; 140:4129-44. [PMID: 24086078 DOI: 10.1242/dev.091793] [Citation(s) in RCA: 417] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sox transcription factors play widespread roles during development; however, their versatile funtions have a relatively simple basis: the binding of a Sox protein alone to DNA does not elicit transcriptional activation or repression, but requires binding of a partner transcription factor to an adjacent site on the DNA. Thus, the activity of a Sox protein is dependent upon the identity of its partner factor and the context of the DNA sequence to which it binds. In this Primer, we provide an mechanistic overview of how Sox family proteins function, as a paradigm for transcriptional regulation of development involving multi-transcription factor complexes, and we discuss how Sox factors can thus regulate diverse processes during development.
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Affiliation(s)
- Yusuke Kamachi
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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29
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Wu SC, Rau CS, Lu TH, Wu CJ, Wu YC, Tzeng SL, Chen YC, Hsieh CH. Knockout of TLR4 and TLR2 impair the nerve regeneration by delayed demyelination but not remyelination. J Biomed Sci 2013; 20:62. [PMID: 23984978 PMCID: PMC3765918 DOI: 10.1186/1423-0127-20-62] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/27/2013] [Indexed: 01/09/2023] Open
Abstract
Background Knockout of either toll-like receptor 4 (TLR4) or 2 (TLR2) had been reported to delay the Wallerian degeneration after peripheral nerve injury by deterring the recruitment of the macrophages and clearance of myelin debris. However, the impact on the remyelination process is poorly understood. In this study, the effect of TLR2 and TLR4 knockout on the nerve regeneration and on the remyelination process was studied in a mouse model of sciatic nerve crush injury. Results A standard sciatic nerve crush injury by a No. 5 Jeweler forcep for consistent 30 seconds was performed in Tlr4−/− (B6.B10ScN-Tlr4lps-del/JthJ), Tlr2−/− (B6.129-Tlr2tm1Kir/J) and C57BL/6 mice. One centimeter of nerve segment distal to the crushed site was harvested for western blot analysis of the myelin structure protein myelin protein zero (Mpz) and the remyelination transcription factors Oct6 and Sox10 at day 0, 3, 7, 10, 14, 17, 21, 28. Nerve segment 5-mm distal to injured site from additional groups of mice at day 10 after crush injury were subjected to semi-thin section and toluidine blue stain for a quantitative histomorphometric analysis. With less remyelinated nerves and more nerve debris, the histomorphometric analysis revealed a worse nerve regeneration following the sciatic nerve crush injury in both Tlr4−/− and Tlr2−/− mice than the C57BL/6 mice. Although there was a delayed expression of Sox10 but not Oct6 during remyelination, with an average 4-day delay in the demyelination process, the subsequent complete formation of Mpz during remyelination was also delayed for 4 days, implying that the impaired nerve regeneration was mainly attributed to the delayed demyelination process. Conclusions Both TLR4 and TLR2 are crucial for nerve regeneration after nerve crush injury mainly by delaying the demyelination but not the remyelination process.
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Affiliation(s)
- Shao-Chun Wu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No, 123, Ta-Pei Road, Niao-Sung District, Kaohsiung City, 833, Taiwan.
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SWI/SNF enzymes promote SOX10- mediated activation of myelin gene expression. PLoS One 2013; 8:e69037. [PMID: 23874858 PMCID: PMC3712992 DOI: 10.1371/journal.pone.0069037] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 06/04/2013] [Indexed: 12/21/2022] Open
Abstract
SOX10 is a Sry-related high mobility (HMG)-box transcriptional regulator that promotes differentiation of neural crest precursors into Schwann cells, oligodendrocytes, and melanocytes. Myelin, formed by Schwann cells in the peripheral nervous system, is essential for propagation of nerve impulses. SWI/SNF complexes are ATP dependent chromatin remodeling enzymes that are critical for cellular differentiation. It was recently demonstrated that the BRG1 subunit of SWI/SNF complexes activates SOX10 expression and also interacts with SOX10 to activate expression of OCT6 and KROX20, two transcriptional regulators of Schwann cell differentiation. To determine the requirement for SWI/SNF enzymes in the regulation of genes that encode components of myelin, which are downstream of these transcriptional regulators, we introduced SOX10 into fibroblasts that inducibly express dominant negative versions of the SWI/SNF ATPases, BRM or BRG1. Dominant negative BRM and BRG1 have mutations in the ATP binding site and inhibit gene activation events that require SWI/SNF function. Ectopic expression of SOX10 in cells derived from NIH 3T3 fibroblasts led to the activation of the endogenous Schwann cell specific gene, myelin protein zero (MPZ) and the gene that encodes myelin basic protein (MBP). Thus, SOX10 reprogrammed these cells into myelin gene expressing cells. Ectopic expression of KROX20 was not sufficient for activation of these myelin genes. However, KROX20 together with SOX10 synergistically activated MPZ and MBP expression. Dominant negative BRM and BRG1 abrogated SOX10 mediated activation of MPZ and MBP and synergistic activation of these genes by SOX10 and KROX20. SOX10 was required to recruit BRG1 to the MPZ locus. Similarly, in immortalized Schwann cells, BRG1 recruitment to SOX10 binding sites at the MPZ locus was dependent on SOX10 and expression of dominant negative BRG1 inhibited expression of MPZ and MBP in these cells. Thus, SWI/SNF enzymes cooperate with SOX10 to directly activate genes that encode components of peripheral myelin.
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31
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NF-κB forms a complex with the chromatin remodeler BRG1 to regulate Schwann cell differentiation. J Neurosci 2013; 33:2388-97. [PMID: 23392668 DOI: 10.1523/jneurosci.3223-12.2013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the developing peripheral nervous system, axon-derived signals stimulate Schwann cells to undergo a global genetic reprogramming involving the cessation of cellular division and the upregulation of myelin genes. How such a comprehensive change in gene transcription is regulated is poorly understood. Here we report that BRG1/SMARCA4, the central helicase of the mammalian SWI/SNF-related chromatin remodeling complex, is required for Schwann cells to differentiate and form myelin, both in vitro and in vivo, in the mouse. BRG1 was highly activated in Schwann cells at early stages of myelination, and loss of the enzyme inhibited their differentiation and completely prevented myelin formation. Furthermore, we identify NF-κB as a key transcription factor that associates with the BRG1 complex in response to neuregulin 1 type III. During myelination, BRG1 was activated through the formation of a complex with NF-κB, and both proteins bound to the promoter region of Sox10, an inducer of myelination. These findings delineate a novel mechanism whereby axonal signals promote myelination through the remodeling of chromatin structure.
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32
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Li J, Parker B, Martyn C, Natarajan C, Guo J. The PMP22 gene and its related diseases. Mol Neurobiol 2012; 47:673-98. [PMID: 23224996 DOI: 10.1007/s12035-012-8370-x] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/22/2012] [Indexed: 10/27/2022]
Abstract
Peripheral myelin protein-22 (PMP22) is primarily expressed in the compact myelin of the peripheral nervous system. Levels of PMP22 have to be tightly regulated since alterations of PMP22 levels by mutations of the PMP22 gene are responsible for >50 % of all patients with inherited peripheral neuropathies, including Charcot-Marie-Tooth type-1A (CMT1A) with trisomy of PMP22, hereditary neuropathy with liability to pressure palsies (HNPP) with heterozygous deletion of PMP22, and CMT1E with point mutations of PMP22. While overexpression and point-mutations of the PMP22 gene may produce gain-of-function phenotypes, deletion of PMP22 results in a loss-of-function phenotype that reveals the normal physiological functions of the PMP22 protein. In this article, we will review the basic genetics, biochemistry and molecular structure of PMP22, followed by discussion of the current understanding of pathogenic mechanisms involving in the inherited neuropathies with mutations in PMP22 gene.
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Affiliation(s)
- Jun Li
- VA Tennessee Valley Healthcare System, 1310 24th Avenue South, Nashville, TN 37212, USA.
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33
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Srinivasan R, Sun G, Keles S, Jones EA, Jang SW, Krueger C, Moran JJ, Svaren J. Genome-wide analysis of EGR2/SOX10 binding in myelinating peripheral nerve. Nucleic Acids Res 2012; 40:6449-60. [PMID: 22492709 PMCID: PMC3413122 DOI: 10.1093/nar/gks313] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 03/25/2012] [Accepted: 03/26/2012] [Indexed: 11/17/2022] Open
Abstract
Myelin is essential for the rapidity of saltatory nerve conduction, and also provides trophic support for axons to prevent axonal degeneration. Two critical determinants of myelination are SOX10 and EGR2/KROX20. SOX10 is required for specification of Schwann cells from neural crest, and is required at every stage of Schwann cell development. Egr2/Krox20 expression is activated by axonal signals in myelinating Schwann cells, and is required for cell cycle arrest and myelin formation. To elucidate the integrated function of these two transcription factors during peripheral nerve myelination, we performed in vivo ChIP-Seq analysis of myelinating peripheral nerve. Integration of these binding data with loss-of-function array data identified a range of genes regulated by these factors. In addition, although SOX10 itself regulates Egr2/Krox20 expression, leading to coordinate activation of several major myelin genes by the two factors, there is a large subset of genes that are activated independent of EGR2. Finally, the results identify a set of SOX10-dependent genes that are expressed in early Schwann cell development, but become subsequently repressed by EGR2/KROX20.
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Affiliation(s)
- Rajini Srinivasan
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - Guannan Sun
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - Sunduz Keles
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - Erin A. Jones
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - Sung-Wook Jang
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - Courtney Krueger
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - John J. Moran
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
| | - John Svaren
- Waisman Center, Department of Statistics, Department of Biostatistics and Medical Informatics, Program in Cellular and Molecular Biology and, Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA
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34
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Abstract
Schwann cells are the main glial cell type in the PNS. They develop along nerves during embryogenesis and rely on the HMG domain containing Sox10 transcription factor for specification, lineage progression, and terminal differentiation. Sox10 deletion in immature Schwann cells caused peripheral nerve defects in mice that were not restricted to this glial cell type, although expression in the nerve and gene loss were. Formation of the perineurium as the protecting sheath was, for instance, heavily compromised. This resembled the defect observed after loss of Desert hedgehog (Dhh) in mice. Here we show that Sox10 activates Dhh expression in Schwann cells via an enhancer that is located in intron 1 of the Dhh gene. Sox10 binds this enhancer in monomeric form via several sites. Mutation of these sites abolishes both Schwann-cell-specific activity and Sox10 responsiveness in vitro and in transgenic mouse embryos. This argues that Sox10 activates Dhh expression by direct binding to the enhancer and by increasing Dhh levels promotes formation of the perineurial sheath. This represents the first mechanism for a non-cell-autonomous function of Sox10 during peripheral nerve development.
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35
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Safka Brožková D, Nevšímalová S, Mazanec R, Rautenstrauss B, Seeman P. Charcot-Marie-Tooth neuropathy due to a novel EGR2 gene mutation with mild phenotype--usefulness of human mapping chip linkage analysis in a Czech family. Neuromuscul Disord 2012; 22:742-6. [PMID: 22546699 DOI: 10.1016/j.nmd.2012.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 03/28/2012] [Accepted: 04/02/2012] [Indexed: 11/19/2022]
Abstract
Charcot-Marie-Tooth neuropathies (CMT) are a group of clinically and genetically heterogeneous disorders of the peripheral nervous system. Selection of candidate disease genes for mutation analysis is sometimes difficult since more than 40 genes and loci are known to be associated with CMT neuropathies. Hence a Czech family Cz-CMT with demyelinating type of autosomal dominant CMT disease was investigated by genome-wide linkage analysis by means of single-nucleotide polymorphism (SNP) arrays. Among 35 regions with linkage, five carried known CMT genes. In the final result a novel early growth response 2 - missense mutation c.1235 A>G, p.Glu412Gly was found. Surprisingly, the more severely affected proband carried an additional heterozygous myelin protein zero variant p.Asp246Asn detected previously, which may modify the phenotype. However, this MPZ variant is benign in heterozygous state alone, because it is also carried by the patient's healthy father.
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Affiliation(s)
- Dana Safka Brožková
- DNA Laboratory, Department of Child Neurology, Charles University 2nd Medical School and University Hospital Motol, Prague, Czech Republic.
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36
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Hossain S, de la Cruz-Morcillo MA, Sanchez-Prieto R, Almazan G. Mitogen-activated protein kinase p38 regulates krox-20 to direct schwann cell differentiation and peripheral myelination. Glia 2012; 60:1130-44. [DOI: 10.1002/glia.22340] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 03/16/2012] [Indexed: 12/24/2022]
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37
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Jones EA, Brewer MH, Srinivasan R, Krueger C, Sun G, Charney KN, Keles S, Antonellis A, Svaren J. Distal enhancers upstream of the Charcot-Marie-Tooth type 1A disease gene PMP22. Hum Mol Genet 2012; 21:1581-91. [PMID: 22180461 PMCID: PMC3298281 DOI: 10.1093/hmg/ddr595] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 12/12/2011] [Indexed: 11/14/2022] Open
Abstract
Myelin insulates axons in the peripheral nervous system to allow rapid propagation of action potentials, and proper myelination requires the precise regulation of genes encoding myelin proteins, including PMP22. The correct gene dosage of PMP22 is critical; a duplication of PMP22 is the most common cause of the peripheral neuropathy Charcot-Marie-Tooth Disease (CMT) (classified as type 1A), while a deletion of PMP22 leads to another peripheral neuropathy, hereditary neuropathy with liability to pressure palsies. Recently, duplications upstream of PMP22, but not containing the gene itself, were reported in patients with CMT1A like symptoms, suggesting that this region contains regulators of PMP22. Using chromatin immunoprecipitation analysis of two transcription factors known to upregulate PMP22-EGR2 and SOX10-we found several enhancers in this upstream region that contain open chromatin and direct reporter gene expression in tissue culture and in vivo in zebrafish. These studies provide a novel means to identify critical regulatory elements in genes that are required for myelination, and elucidate the functional significance of non-coding genomic rearrangements.
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Affiliation(s)
- Erin A. Jones
- Program in Cellular and Molecular Biology
- Waisman Center
| | | | | | | | - Guannan Sun
- Department of Statistics
- Department of Biostatistics and Medical Informatics and
| | | | - Sunduz Keles
- Department of Statistics
- Department of Biostatistics and Medical Informatics and
| | - Anthony Antonellis
- Department of Human Genetics
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - John Svaren
- Waisman Center
- Department of Comparative Biosciences, Waisman Center, University of Wisconsin, Madison, WI 53705, USA
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38
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The nucleosome remodeling and deacetylase chromatin remodeling (NuRD) complex is required for peripheral nerve myelination. J Neurosci 2012; 32:1517-27. [PMID: 22302795 DOI: 10.1523/jneurosci.2895-11.2012] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Several key transcription factors and coregulators important to peripheral nerve myelination have been identified, but the contributions of specific chromatin remodeling complexes to peripheral nerve myelination have not been analyzed. Chromodomain helicase DNA-binding protein 4 (Chd4) is the core catalytic subunit of the nucleosome remodeling and deacetylase (NuRD) chromatin remodeling complex. Previous studies have shown Chd4 interacts with Nab (NGFI-A/Egr-binding) corepressors, which are required for early growth response 2 (Egr2/Krox20), to direct peripheral nerve myelination by Schwann cells. In this study, we examined the developmental importance of the NuRD complex in peripheral nerve myelination through the generation of conditional Chd4 knock-out mice in Schwann cells (Chd4(loxP/loxP); P0-cre). Chd4 conditional null mice were found to have delayed myelination, radial sorting defects, hypomyelination, and the persistence of promyelinating Schwann cells. Loss of Chd4 leads to elevated expression of immature Schwann cell genes (Id2, c-Jun, and p75), and sustained expression of the promyelinating Schwann cell gene, Oct6/Scip, without affecting the levels of Egr2/Krox20. Furthermore, Schwann cell proliferation is upregulated in Chd4-null sciatic nerve. In vivo chromatin immunoprecipitation studies reveal recruitment of Chd4 and another NuRD component, Mta2, to genes that are positively and negatively regulated by Egr2 during myelination. Together, these results underscore the necessity of Chd4 function to guide proper terminal differentiation of Schwann cells and implicate the NuRD chromatin remodeling complex as a requisite factor in timely and stable peripheral nerve myelination.
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Fröb F, Bremer M, Finzsch M, Kichko T, Reeh P, Tamm ER, Charnay P, Wegner M. Establishment of myelinating schwann cells and barrier integrity between central and peripheral nervous systems depend on Sox10. Glia 2012; 60:806-19. [DOI: 10.1002/glia.22310] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 01/24/2012] [Indexed: 11/05/2022]
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40
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Vincristine exacerbates asymptomatic Charcot–Marie–Tooth disease with a novel EGR2 mutation. Neurogenetics 2012; 13:77-82. [DOI: 10.1007/s10048-012-0313-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
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41
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Gokey NG, Srinivasan R, Lopez-Anido C, Krueger C, Svaren J. Developmental regulation of microRNA expression in Schwann cells. Mol Cell Biol 2012; 32:558-68. [PMID: 22064487 PMCID: PMC3255778 DOI: 10.1128/mcb.06270-11] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/30/2011] [Indexed: 01/07/2023] Open
Abstract
Schwann cell differentiation and subsequent myelination of the peripheral nervous system require the action of several transcription factors, including Sox10, which is vital at multiple stages of development. The transition from immature to myelinating Schwann cell is also regulated posttranscriptionally and depends upon Dicer-mediated processing of microRNAs (miRNAs). Although specific miRNA targets have begun to be identified, the mechanisms establishing the dynamic regulation of miRNA expression have not been elucidated. We performed expression profiling studies and identified 225 miRNAs differentially expressed during peripheral myelination. A subset of 9 miRNAs is positively regulated by Sox10, including miR-338 which has been implicated in oligodendrocyte maturation. In vivo chromatin immunoprecipitation (ChIP) of sciatic nerve cells revealed a Sox10 binding site upstream of an alternate promoter within the Aatk gene, which hosts miR-338. Sox10 occupied this site in spinal cord ChIP experiments, suggesting a similar regulatory mechanism in oligodendrocytes. Cancer profiling studies have identified clusters of miRNAs that regulate proliferation, termed "oncomirs." In Schwann cells, the expression of many of these proproliferative miRNAs was reduced in the absence of Sox10. Finally, Schwann cells with reduced Sox10 and oncomir expression have an increase in the CDK inhibitor p21 and a concomitant reduction in cell proliferation.
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Affiliation(s)
| | | | | | | | - John Svaren
- Waisman Center
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, Wisconsin, USA
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42
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Espinós C, Calpena E, Martínez-Rubio D, Lupo V. Autosomal Recessive Charcot-Marie-Tooth Neuropathy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 724:61-75. [DOI: 10.1007/978-1-4614-0653-2_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Bremer M, Fröb F, Kichko T, Reeh P, Tamm ER, Suter U, Wegner M. Sox10 is required for Schwann-cell homeostasis and myelin maintenance in the adult peripheral nerve. Glia 2011; 59:1022-32. [PMID: 21491499 DOI: 10.1002/glia.21173] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 03/16/2011] [Indexed: 11/07/2022]
Abstract
The transcription factor Sox10 functions during multiple consecutive stages of Schwann-cell development in the peripheral nervous system (PNS). Although Sox10 continues to be expressed in mature Schwann cells of the adult peripheral nerve, it is currently unclear whether it is still functional. Here, we used a genetic strategy to selectively delete Sox10 in glia of adult mice in a tamoxifen-dependent manner. The tamoxifen-treated mice developed a severe peripheral neuropathy that was associated with dramatic alterations in peripheral nerve structure and function. Demyelination and axonal degeneration were as much evident as signs of neuroinflammation. Compound action potentials exhibited pathophysiological alterations. Sox10-deleted Schwann cells persisted in the peripheral nerve, but did not exhibit a mature, myelinating phenotype arguing that Sox10 is rather required for differentiation and maintenance of the differentiated state than for survival. Our report is the first evidence that Sox10 is still essentially required for Schwann-cell function in the adult PNS and establishes a useful model in which to study human peripheral neuropathies.
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Affiliation(s)
- Magdalena Bremer
- Institut für Biochemie, Emil-Fischer-Zentrum, Universität Erlangen-Nürnberg, Erlangen, Germany
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Jones EA, Lopez-Anido C, Srinivasan R, Krueger C, Chang LW, Nagarajan R, Svaren J. Regulation of the PMP22 gene through an intronic enhancer. J Neurosci 2011; 31:4242-50. [PMID: 21411665 PMCID: PMC3100536 DOI: 10.1523/jneurosci.5893-10.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/17/2011] [Accepted: 01/21/2011] [Indexed: 11/21/2022] Open
Abstract
Successful myelination of the peripheral nervous system depends upon induction of major protein components of myelin, such as peripheral myelin protein 22 (PMP22). Myelin stability is also sensitive to levels of PMP22, as a 1.4 Mb duplication on human chromosome 17, resulting in three copies of PMP22, is the most common cause of the peripheral neuropathy Charcot-Marie-Tooth disease. The transcription factor Egr2/Krox20 is required for induction of high level expression of Pmp22 in Schwann cells but its activation elements have not yet been determined. Using chromatin immunoprecipitation analysis of the rat Pmp22 locus, we found a major peak of Egr2 binding within the large intron of the Pmp22 gene. Analysis of a 250 bp region within the largest intron showed that it is strongly activated by Egr2 expression in reporter assays. Moreover, this region contains conserved binding sites not only for Egr2 but also for Sox10, which is also required for Schwann cell development. Our analysis shows that Sox10 is required for optimal activity of the intronic site as well as PMP22 expression. Finally, mouse transgenic analysis revealed tissue-specific expression of this intronic sequence in peripheral nerve. Overall, these data show that Egr2 and Sox10 activity are directly involved in mediating the developmental induction of Pmp22 expression.
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Affiliation(s)
| | | | - Rajini Srinivasan
- Waisman Center, University of Wisconsin, Madison, Wisconsin 53705, and
| | - Courtney Krueger
- Waisman Center, University of Wisconsin, Madison, Wisconsin 53705, and
| | - Li-Wei Chang
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Rakesh Nagarajan
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - John Svaren
- Department of Comparative Biosciences, and
- Waisman Center, University of Wisconsin, Madison, Wisconsin 53705, and
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Antonellis A, Dennis MY, Burzynski G, Huynh J, Maduro V, Hodonsky CJ, Khajavi M, Szigeti K, Mukkamala S, Bessling SL, Pavan WJ, McCallion AS, Lupski JR, Green ED. A rare myelin protein zero (MPZ) variant alters enhancer activity in vitro and in vivo. PLoS One 2010; 5:e14346. [PMID: 21179557 PMCID: PMC3002941 DOI: 10.1371/journal.pone.0014346] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 11/26/2010] [Indexed: 01/16/2023] Open
Abstract
Background Myelin protein zero (MPZ) is a critical structural component of myelin in the peripheral nervous system. The MPZ gene is regulated, in part, by the transcription factors SOX10 and EGR2. Mutations in MPZ, SOX10, and EGR2 have been implicated in demyelinating peripheral neuropathies, suggesting that components of this transcriptional network are candidates for harboring disease-causing mutations (or otherwise functional variants) that affect MPZ expression. Methodology We utilized a combination of multi-species sequence comparisons, transcription factor-binding site predictions, targeted human DNA re-sequencing, and in vitro and in vivo enhancer assays to study human non-coding MPZ variants. Principal Findings Our efforts revealed a variant within the first intron of MPZ that resides within a previously described SOX10 binding site is associated with decreased enhancer activity, and alters binding of nuclear proteins. Additionally, the genomic segment harboring this variant directs tissue-relevant reporter gene expression in zebrafish. Conclusions This is the first reported MPZ variant within a cis-acting transcriptional regulatory element. While we were unable to implicate this variant in disease onset, our data suggests that similar non-coding sequences should be screened for mutations in patients with neurological disease. Furthermore, our multi-faceted approach for examining the functional significance of non-coding variants can be readily generalized to study other loci important for myelin structure and function.
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Affiliation(s)
- Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Megan Y. Dennis
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Grzegorz Burzynski
- McKusick–Nathans Institute of Genetic Medicine and Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jimmy Huynh
- McKusick–Nathans Institute of Genetic Medicine and Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Valerie Maduro
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Chani J. Hodonsky
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Mehrdad Khajavi
- Department of Molecular and Human Genetics, Houston, Texas, United States of America
| | - Kinga Szigeti
- Department of Molecular and Human Genetics, Houston, Texas, United States of America
- Department of Neurology, Houston, Texas, United States of America
| | - Sandeep Mukkamala
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Seneca L. Bessling
- McKusick–Nathans Institute of Genetic Medicine and Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - NISC Comparative Sequencing Program
- NIH Intramural Sequencing Center (NISC), National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - William J. Pavan
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Andrew S. McCallion
- McKusick–Nathans Institute of Genetic Medicine and Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - James R. Lupski
- Department of Molecular and Human Genetics, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children's Hospital, Houston, Texas, United States of America
| | - Eric D. Green
- Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- NIH Intramural Sequencing Center (NISC), National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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46
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Jang SW, Srinivasan R, Jones EA, Sun G, Keles S, Krueger C, Chang LW, Nagarajan R, Svaren J. Locus-wide identification of Egr2/Krox20 regulatory targets in myelin genes. J Neurochem 2010; 115:1409-20. [PMID: 21044070 PMCID: PMC3260055 DOI: 10.1111/j.1471-4159.2010.07045.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Myelination of peripheral nerves by Schwann cells depends upon a gene regulatory network controlled by early growth response Egr2/Krox20, which is specifically required for Schwann cells to initiate and maintain myelination. To elucidate the mechanism by which Egr2 regulates gene expression during myelination, we have performed chromatin immunoprecipitation analysis on myelinating rat sciatic nerve in vivo. The resulting samples were applied to a tiled microarray consisting of a broad spectrum of genes that are activated or repressed in Egr2-deficient mice. The results show extensive binding within myelin-associated genes, as well as some genes that become repressed in myelinating Schwann cells. Many of the Egr2 peaks coincide with regions of open chromatin, which is a marker of enhancer regions. In addition, further analysis showed that there is substantial colocalization of Egr2 binding with Sox10, a transcription factor required for Schwann cell specification and other stages of Schwann cell development. Finally, we have found that Egr2 binds to promoters of several lipid biosynthetic genes, which is consistent with their dramatic up-regulation during the formation of lipid-rich myelin. Overall, this analysis provides a locus-wide profile of Egr2 binding patterns in major myelin-associated genes using myelinating peripheral nerve.
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Affiliation(s)
- Sung-Wook Jang
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Erin A. Jones
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Guannan Sun
- Department of Statistics, Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, USA
| | - Sunduz Keles
- Department of Statistics, Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, USA
| | - Courtney Krueger
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Li-Wei Chang
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Rakesh Nagarajan
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - John Svaren
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
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Lei L, Han D, Gong S, Zheng J, Xu J. Mpz gene suppression by shRNA increases Schwann cell apoptosis in vitro. Neurol Sci 2010; 31:603-8. [PMID: 20552241 DOI: 10.1007/s10072-010-0341-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Accepted: 05/22/2010] [Indexed: 11/29/2022]
Abstract
We investigated the effects of short hairpin RNA (shRNA) on myelin protein zero (MPZ) gene expression in Schwann cells (SCs) in vitro and determined the effects of the MPZ gene suppression on the survival of SCs. The MPZ-specific shRNA was introduced into a lentiviral vector for expression under the U6 promoter, and the viral vector-based shRNAs were used to infect cultured SCs. The efficiency of MPZ knockdown was analyzed by real time-PCR (RT-PCR) and western blotting. Flow cytometric analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were used to determine the cell cycle and the amount of apoptosis of SCs. We found that MPZ shRNAs significantly inhibited the expression of the MPZ gene and induced SC apoptosis in vitro. These results provided interesting experimental evidence for understanding the mechanism of demyelinating neuropathies caused by MPZ gene malfunction.
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Affiliation(s)
- Li Lei
- Department of Otolaryngology, Affiliated Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang, Dongcheng District, Beijing, 100730, People's Republic of China
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Masuda T, Esumi N. SOX9, through interaction with microphthalmia-associated transcription factor (MITF) and OTX2, regulates BEST1 expression in the retinal pigment epithelium. J Biol Chem 2010; 285:26933-26944. [PMID: 20530484 DOI: 10.1074/jbc.m110.130294] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BEST1 is highly and preferentially expressed in the retinal pigment epithelium (RPE) and causes Best macular dystrophy when mutated. We previously demonstrated that the human BEST1 upstream region -154 to +38 bp is sufficient to direct expression in the RPE of transgenic mice, and microphthalmia-associated transcription factor (MITF) and OTX2 regulate this BEST1 promoter. However, a number of questions remained. Here, we show that yeast one-hybrid screen with bait corresponding to BEST1 -120 to -88 bp identified the SOX-E factors, SOX8, SOX9, and SOX10. A paired SOX site was found in this bait, and mutation of either of the paired sites significantly decreased BEST1 promoter activity in RPE primary cultures. Among the SOX-E genes, SOX9 is highly and preferentially expressed in the RPE, and chromatin immunoprecipitation with fresh RPE cells revealed binding of SOX9, but not SOX10, to the BEST1 region where the paired SOX site is located. BEST1 promoter activity was increased by SOX9 overexpression and decreased by siRNA-mediated SOX9 knockdown. Importantly, SOX9 physically interacted with MITF and OTX2 and orchestrated synergistic activation of the BEST1 promoter with the paired SOX site playing essential roles. A combination of the expression patterns of SOX9, MITF, and OTX2 yielded tissue distribution remarkably similar to that of BEST1. Lastly, the BEST1 promoter was also active in Sertoli cells of the testis in transgenic mice where SOX9 is highly expressed. These results define SOX9 as a key regulator of BEST1 expression and demonstrate for the first time its functional role in the RPE.
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Affiliation(s)
- Tomohiro Masuda
- Guerrieri Center for Genetic Engineering and Molecular Ophthalmology at The Wilmer Eye Institute and the Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | - Noriko Esumi
- Guerrieri Center for Genetic Engineering and Molecular Ophthalmology at The Wilmer Eye Institute and the Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287.
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Finzsch M, Schreiner S, Kichko T, Reeh P, Tamm ER, Bösl MR, Meijer D, Wegner M. Sox10 is required for Schwann cell identity and progression beyond the immature Schwann cell stage. ACTA ACUST UNITED AC 2010; 189:701-12. [PMID: 20457761 PMCID: PMC2872908 DOI: 10.1083/jcb.200912142] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mutations in the transcription factor SOX10 cause neurocristopathies, including Waardenburg-Hirschsprung syndrome and peripheral neuropathies in humans. This is partly attributed to a requirement for Sox10 in early neural crest for survival, maintenance of pluripotency, and specification to several cell lineages, including peripheral glia. As a consequence, peripheral glia are absent in Sox10-deficient mice. Intriguingly, Sox10 continues to be expressed in these cells after specification. To analyze glial functions after specification, we specifically deleted Sox10 in immature Schwann cells by conditional mutagenesis. Mutant mice died from peripheral neuropathy before the seventh postnatal week. Nerve alterations included a thinned perineurial sheath, increased lipid and collagen deposition, and a dramatically altered cellular composition. Nerve conduction was also grossly aberrant, and neither myelinating nor nonmyelinating Schwann cells formed. Instead, axons of different sizes remained unsorted in large bundles. Schwann cells failed to develop beyond the immature stage and were unable to maintain identity. Thus, our study identifies a novel cause for peripheral neuropathies in patients with SOX10 mutations.
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Affiliation(s)
- Markus Finzsch
- Institut für Biochemie, Emil-Fischer-Zentrum, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
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50
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Harris ML, Baxter LL, Loftus SK, Pavan WJ. Sox proteins in melanocyte development and melanoma. Pigment Cell Melanoma Res 2010; 23:496-513. [PMID: 20444197 DOI: 10.1111/j.1755-148x.2010.00711.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over 10 years have passed since the first Sox gene was implicated in melanocyte development. Since then, we have discovered that SOX5, SOX9, SOX10 and SOX18 all participate as transcription factors that affect key melanocytic genes in both regulatory and modulatory fashions. Both SOX9 and SOX10 play major roles in the establishment and normal function of the melanocyte; SOX10 has been shown to heavily influence melanocyte development and SOX9 has been implicated in melanogenesis in the adult. Despite these advances, the precise cellular and molecular details of how these SOX proteins are regulated and interact during all stages of the melanocyte life cycle remain unknown. Improper regulation of SOX9 or SOX10 is also associated with cancerous transformation, and thus understanding the normal function of SOX proteins in the melanocyte will be key to revealing how these proteins contribute to melanoma.
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Affiliation(s)
- Melissa L Harris
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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