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Bagheri H, Friedman H, Hadwen A, Jarweh C, Cooper E, Oprea L, Guerrier C, Khadra A, Collin A, Cohen-Adad J, Young A, Victoriano GM, Swire M, Jarjour A, Bechler ME, Pryce RS, Chaurand P, Cougnaud L, Vuckovic D, Wilion E, Greene O, Nishiyama A, Benmamar-Badel A, Owens T, Grouza V, Tuznik M, Liu H, Rudko DA, Zhang J, Siminovitch KA, Peterson AC. Myelin basic protein mRNA levels affect myelin sheath dimensions, architecture, plasticity, and density of resident glial cells. Glia 2024; 72:1893-1914. [PMID: 39023138 DOI: 10.1002/glia.24589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2024] [Revised: 05/29/2024] [Accepted: 06/23/2024] [Indexed: 07/20/2024]
Abstract
Myelin Basic Protein (MBP) is essential for both elaboration and maintenance of CNS myelin, and its reduced accumulation results in hypomyelination. How different Mbp mRNA levels affect myelin dimensions across the lifespan and how resident glial cells may respond to such changes are unknown. Here, to investigate these questions, we used enhancer-edited mouse lines that accumulate Mbp mRNA levels ranging from 8% to 160% of wild type. In young mice, reduced Mbp mRNA levels resulted in corresponding decreases in Mbp protein accumulation and myelin sheath thickness, confirming the previously demonstrated rate-limiting role of Mbp transcription in the control of initial myelin synthesis. However, despite maintaining lower line specific Mbp mRNA levels into old age, both MBP protein levels and myelin thickness improved or fully normalized at rates defined by the relative Mbp mRNA level. Sheath length, in contrast, was affected only when mRNA levels were very low, demonstrating that sheath thickness and length are not equally coupled to Mbp mRNA level. Striking abnormalities in sheath structure also emerged with reduced mRNA levels. Unexpectedly, an increase in the density of all glial cell types arose in response to reduced Mbp mRNA levels. This investigation extends understanding of the role MBP plays in myelin sheath elaboration, architecture, and plasticity across the mouse lifespan and illuminates a novel axis of glial cell crosstalk.
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Affiliation(s)
- Hooman Bagheri
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Hana Friedman
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Amanda Hadwen
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Celia Jarweh
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Ellis Cooper
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Lawrence Oprea
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | | | - Anmar Khadra
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Armand Collin
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada
| | - Julien Cohen-Adad
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada
| | - Amanda Young
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Gerardo Mendez Victoriano
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Matthew Swire
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Andrew Jarjour
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Marie E Bechler
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Rachel S Pryce
- Department of Chemistry, Université de Montréal, Montreal, Quebec, Canada
| | - Pierre Chaurand
- Department of Chemistry, Université de Montréal, Montreal, Quebec, Canada
| | - Lise Cougnaud
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Dajana Vuckovic
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Elliott Wilion
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Owen Greene
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, USA
- The Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut, USA
| | - Anouk Benmamar-Badel
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Trevor Owens
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Vladimir Grouza
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Marius Tuznik
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Hanwen Liu
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - David A Rudko
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Jinyi Zhang
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Katherine A Siminovitch
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Alan C Peterson
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, McGill University, Quebec, Canada
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Osanai Y, Xing YL, Mochizuki S, Kobayashi K, Homman-Ludiye J, Cooray A, Poh J, Inutsuka A, Ohno N, Merson TD. 5' Transgenes drive leaky expression of 3' transgenes in Cre-inducible bi-cistronic vectors. Mol Ther Methods Clin Dev 2024; 32:101288. [PMID: 39104576 PMCID: PMC11298883 DOI: 10.1016/j.omtm.2024.101288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 06/21/2024] [Indexed: 08/07/2024]
Abstract
Molecular cloning techniques enabling contemporaneous expression of two or more protein-coding sequences provide an invaluable tool for understanding the molecular regulation of cellular functions. The Cre-lox system is used for inducing the expression of recombinant proteins encoded within a bi-/poly-cistronic cassette. However, leak expression of transgenes is often observed in the absence of Cre recombinase activity, compromising the utility of this approach. To investigate the mechanism of leak expression, we generated Cre-inducible bi-cistronic vectors to monitor the expression of transgenes positioned either 5' or 3' of a 2A peptide or internal ribosomal entry site (IRES) sequence. Cells transfected with these bi-cistronic vectors exhibited Cre-independent leak expression specifically of transgenes positioned 3' of the 2A peptide or IRES sequence. Similarly, AAV-FLEX vectors encoding bi-cistronic cassettes or fusion proteins revealed the selective Cre-independent leak expression of transgenes positioned at the 3' end of the open reading frame. Our data demonstrate that 5' transgenes confer promoter-like activity that drives the expression of 3' transgenes. An additional lox-STOP-lox cassette between the 2A sequence and 3' transgene dramatically decreased Cre-independent transgene expression. Our findings highlight the need for appropriate experimental controls when using Cre-inducible bi-/poly-cistronic constructs and inform improved design of vectors for more tightly regulated inducible transgene expression.
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Affiliation(s)
- Yasuyuki Osanai
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC 3800, Australia
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Tochigi 329-0431, Japan
| | - Yao Lulu Xing
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC 3800, Australia
| | - Shinya Mochizuki
- Department of Anatomy, Bioimaging and Neuro-cell Science, Jichi Medical University, Shimotsuke, Tochigi 329-0431, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan
- The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Jihane Homman-Ludiye
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC 3800, Australia
| | - Amali Cooray
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC 3800, Australia
| | - Jasmine Poh
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC 3800, Australia
| | - Ayumu Inutsuka
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, Shimotsuke, Tochigi 329-0431, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Tochigi 329-0431, Japan
- Division of Ultrastructure Research, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan
| | - Tobias D. Merson
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC 3800, Australia
- Oligodendroglial Interactions Group, Systems Neurodevelopment Laboratory, National Institute of Mental Health, Bethesda, MD 20892, USA
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Prazak L, Iwasaki Y, Kim AR, Kozlov K, King K, Gergen JP. A dual role for DNA binding by Runt in activation and repression of sloppy paired transcription. Mol Biol Cell 2021; 32:ar26. [PMID: 34432496 PMCID: PMC8693977 DOI: 10.1091/mbc.e20-08-0509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
This work investigates the role of DNA binding by Runt in regulating the sloppy paired 1 (slp1) gene and in particular two distinct cis-regulatory elements that mediate regulation by Runt and other pair-rule transcription factors during Drosophila segmentation. We find that a DNA-binding-defective form of Runt is ineffective at repressing both the distal (DESE) and proximal (PESE) early stripe elements of slp1 and is also compromised for DESE-dependent activation. The function of Runt-binding sites in DESE is further investigated using site-specific transgenesis and quantitative imaging techniques. When DESE is tested as an autonomous enhancer, mutagenesis of the Runt sites results in a clear loss of Runt-dependent repression but has little to no effect on Runt-dependent activation. Notably, mutagenesis of these same sites in the context of a reporter gene construct that also contains the PESE enhancer results in a significant reduction of DESE-dependent activation as well as the loss of repression observed for the autonomous mutant DESE enhancer. These results provide strong evidence that DNA binding by Runt directly contributes to the regulatory interplay of interactions between these two enhancers in the early embryo.
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Affiliation(s)
- Lisa Prazak
- Department of Biology, Farmingdale State College, Farmingdale, NY 11735-1021.,Department of Biochemistry and Cell Biology and Center for Developmental Genetics.,Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - Yasuno Iwasaki
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics
| | - Ah-Ram Kim
- Graduate Program in Biochemistry and Structural Biology, and
| | - Konstantin Kozlov
- Department of Applied Mathematics, St. Petersburg State Polytechnical University, St. Petersburg, Russia 195251
| | - Kevin King
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics.,Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY 11794-5215
| | - J Peter Gergen
- Department of Biochemistry and Cell Biology and Center for Developmental Genetics
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Swire M, Assinck P, McNaughton PA, Lyons DA, Ffrench-Constant C, Livesey MR. Oligodendrocyte HCN2 Channels Regulate Myelin Sheath Length. J Neurosci 2021; 41:7954-7964. [PMID: 34341156 PMCID: PMC8460148 DOI: 10.1523/jneurosci.2463-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 06/16/2021] [Accepted: 07/06/2021] [Indexed: 11/21/2022] Open
Abstract
Oligodendrocytes generate myelin sheaths vital for the formation, health, and function of the CNS. Myelin sheath length is a key property that determines axonal conduction velocity and is known to be variable across the CNS. Myelin sheath length can be modified by neuronal activity, suggesting that dynamic regulation of sheath length might contribute to the functional plasticity of neural circuits. Although the mechanisms that establish and refine myelin sheath length are important determinants of brain function, our understanding of these remains limited. In recent years, the membranes of myelin sheaths have been increasingly recognized to contain ion channels and transporters that are associated with specific important oligodendrocyte functions, including metabolic support of axons and the regulation of ion homeostasis, but none have been shown to influence sheath architecture. In this study, we determined that hyperpolarization-activated, cyclic nucleotide-gated (HCN) ion channels, typically associated with neuronal and cardiac excitability, regulate myelin sheath length. Using both in vivo and in vitro approaches, we show that oligodendrocytes abundantly express functional, predominantly HCN2 subunit-containing ion channels. These HCN ion channels retain key pharmacological and biophysical features and regulate the resting membrane potential of myelinating oligodendrocytes. Further, reduction of their function via pharmacological blockade or generation of transgenic mice with two independent oligodendrocyte-specific HCN2 knock-out strategies reduced myelin sheath length. We conclude that HCN2 ion channels are key determinants of myelin sheath length in the CNS.SIGNIFICANCE STATEMENT Myelin sheath length is a critical determinant of axonal conduction velocity, but the signaling mechanisms responsible for determining sheath length are poorly understood. Here we find that oligodendrocytes express functional hyperpolarization-activated, cyclic nucleotide-gated 2 (HCN2) ion channels that regulate the length of myelin sheaths formed by oligodendrocytes in myelinating cultures and in the mouse brain and spinal cord. These results suggest that the regulation of HCN2 channel activity is well placed to refine sheath length and conduction along myelinated axons, providing a potential mechanism for alterations in conduction velocity and circuit function in response to axonal signals such as those generated by increased activity.
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Affiliation(s)
- Matthew Swire
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
| | - Peggy Assinck
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Peter A McNaughton
- Wolfson Centre for Age-Related Diseases, King's College London, London WC2R 2LS, United Kingdom
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Charles Ffrench-Constant
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh EH16 4UU, United Kingdom
| | - Matthew R Livesey
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, United Kingdom
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5
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Bagheri H, Friedman H, Siminovitch KA, Peterson AC. Transcriptional regulators of the Golli/myelin basic protein locus integrate additive and stealth activities. PLoS Genet 2020; 16:e1008752. [PMID: 32790717 PMCID: PMC7446974 DOI: 10.1371/journal.pgen.1008752] [Citation(s) in RCA: 3] [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: 03/26/2020] [Revised: 08/25/2020] [Accepted: 07/01/2020] [Indexed: 11/19/2022] Open
Abstract
Myelin is composed of plasma membrane spirally wrapped around axons and compacted into dense sheaths by myelin-associated proteins. Myelin is elaborated by neuroepithelial derived oligodendrocytes in the central nervous system (CNS) and by neural crest derived Schwann cells in the peripheral nervous system (PNS). While some myelin proteins accumulate in only one lineage, myelin basic protein (Mbp) is expressed in both. Overlapping the Mbp gene is Golli, a transcriptional unit that is expressed widely both within and beyond the nervous system. A super-enhancer domain within the Golli/Mbp locus contains multiple enhancers shown previously to drive reporter construct expression specifically in oligodendrocytes or Schwann cells. In order to determine the contribution of each enhancer to the Golli/Mbp expression program, and to reveal if functional interactions occur among them, we derived mouse lines in which they were deleted, either singly or in different combinations, and relative mRNA accumulation was measured at key stages of early development and at maturity. Although super-enhancers have been shown previously to facilitate interaction among their component enhancers, the enhancers investigated here demonstrated largely additive relationships. However, enhancers demonstrating autonomous activity strictly in one lineage, when missing, were found to significantly reduce output in the other, thus revealing cryptic "stealth" activity. Further, in the absence of a key oligodendrocyte enhancer, Golli accumulation was markedly and uniformly attenuated in all cell types investigated. Our observations suggest a model in which enhancer-mediated DNA-looping and potential super-enhancer properties underlie Golli/Mbp regulatory organization.
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Affiliation(s)
- Hooman Bagheri
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Hana Friedman
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Katherine A. Siminovitch
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Alan C. Peterson
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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6
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Wu Z, Rao Y, Zhang S, Kim EJ, Oki S, Harada H, Cheung M, Jung HS. Cis-control of Six1 expression in neural crest cells during craniofacial development. Dev Dyn 2019; 248:1264-1272. [PMID: 31464047 DOI: 10.1002/dvdy.109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 08/01/2019] [Accepted: 08/18/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Six1 is a transcriptional factor that plays an important role in embryonic development. Mouse and chick embryos deficient for Six1 have multiple craniofacial anomalies in the facial bones and cartilages. Multiple Six1 enhancers have been identified, but none of them has been reported to be active in the maxillary and mandibular process. RESULTS We studied two Six1 enhancers in the chick neural crest tissues during craniofacial development. We showed that two evolutionarily conserved enhancers, Six1E1 and Six1E2, act synergistically. Neither Six1E1 nor Six1E2 alone can drive enhancer reporter signal in the maxillary or mandibular processes. However, their combination, Six1E, showed robust enhancer activity in these tissues. Similar reporter signal can also be driven by the mouse homolog of Six1E. Mutations of multiple conserved transcriptional factor binding sites altered the enhancer activity of Six1E, especially mutation of the LIM homeobox binding site, dramatically reduced the enhancer activity, implying that the Lhx protein family be an important regulator of Six1 expression. CONCLUSION This study, for the first time, described the synergistic activation of two Six1 enhancers in the maxillary and mandibular processes and will facilitate more detailed studies of the regulation of Six1 in craniofacial development.
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Affiliation(s)
- Zhaoming Wu
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Yanxia Rao
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Sushan Zhang
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Eun-Jung Kim
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Shinya Oki
- Department of Basic Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hidemitsu Harada
- Department of Anatomy, Division of Developmental Biology & Regenerative Medicine, Iwate Medical University, 2-1-1 Nishitokuda, Yahaba, Iwate, Japan
| | - Martin Cheung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Han-Sung Jung
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
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7
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Truong PH, Ciccotosto GD, Merson TD, Spoerri L, Chuei MJ, Ayers M, Xing YL, Emery B, Cappai R. Amyloid precursor protein and amyloid precursor-like protein 2 have distinct roles in modulating myelination, demyelination, and remyelination of axons. Glia 2018; 67:525-538. [DOI: 10.1002/glia.23561] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Phan H. Truong
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
| | - Giuseppe D. Ciccotosto
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
| | - Tobias D. Merson
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
| | - Loredana Spoerri
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
| | - Mun Joo Chuei
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
| | - Margaret Ayers
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
| | - Yao Lulu Xing
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
| | - Ben Emery
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
- Department of Anatomy and Neuroscience; The University of Melbourne; Melbourne Victoria Australia
| | - Roberto Cappai
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
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8
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Long HK, Prescott SL, Wysocka J. Ever-Changing Landscapes: Transcriptional Enhancers in Development and Evolution. Cell 2016; 167:1170-1187. [PMID: 27863239 PMCID: PMC5123704 DOI: 10.1016/j.cell.2016.09.018] [Citation(s) in RCA: 564] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/24/2016] [Accepted: 09/07/2016] [Indexed: 12/27/2022]
Abstract
A class of cis-regulatory elements, called enhancers, play a central role in orchestrating spatiotemporally precise gene-expression programs during development. Consequently, divergence in enhancer sequence and activity is thought to be an important mediator of inter- and intra-species phenotypic variation. Here, we give an overview of emerging principles of enhancer function, current models of enhancer architecture, genomic substrates from which enhancers emerge during evolution, and the influence of three-dimensional genome organization on long-range gene regulation. We discuss intricate relationships between distinct elements within complex regulatory landscapes and consider their potential impact on specificity and robustness of transcriptional regulation.
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Affiliation(s)
- Hannah K Long
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Sara L Prescott
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Joanna Wysocka
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA.
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9
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Dionne N, Dib S, Finsen B, Denarier E, Kuhlmann T, Drouin R, Kokoeva M, Hudson TJ, Siminovitch K, Friedman HC, Peterson AC. Functional organization of anMbpenhancer exposes striking transcriptional regulatory diversity within myelinating glia. Glia 2015; 64:175-94. [DOI: 10.1002/glia.22923] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/04/2015] [Accepted: 09/09/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Nancy Dionne
- Laboratory of Developmental Biology; Ludmer Research and Training Building, McGill University; Montreal Quebec Canada
| | - Samar Dib
- Laboratory of Developmental Biology; Ludmer Research and Training Building, McGill University; Montreal Quebec Canada
| | - Bente Finsen
- Department of Neurobiology Research; Institute of Molecular Medicine, University of Southern Denmark; Odense Denmark
| | - Eric Denarier
- Institut National De La Santé Et De La Recherche Médicale, U836-GIN iRTSV-GPC; Site Santé La Tronche, BP170 Grenoble Cedex 9 France
| | - Tanja Kuhlmann
- Institute of Neuropathology, University Hospital, Münster; Pottkamp 2 Münster Germany
| | - Régen Drouin
- Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences; Université De Sherbrooke; Sherbrooke Quebec Canada
| | - Maia Kokoeva
- Department of Medicine; McGill University/MUHC Research Institute; Montreal Quebec Canada
| | - Thomas J. Hudson
- Ontario Institute for Cancer Research, MaRS Centre; South Tower Toronto Ontario Canada
| | - Kathy Siminovitch
- Department of Medicine; University of Toronto, Samuel Lunenfeld and Toronto General Research Institutes; Toronto Ontario Canada
- Department of Immunology and Molecular Genetics; University of Toronto; Toronto Ontario Canada
| | - Hana C Friedman
- Laboratory of Developmental Biology; Ludmer Research and Training Building, McGill University; Montreal Quebec Canada
| | - Alan C. Peterson
- Laboratory of Developmental Biology; Ludmer Research and Training Building, McGill University; Montreal Quebec Canada
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Cédile O, Løbner M, Toft-Hansen H, Frank I, Wlodarczyk A, Irla M, Owens T. Thymic CCL2 influences induction of T-cell tolerance. J Autoimmun 2014; 55:73-85. [PMID: 25129504 DOI: 10.1016/j.jaut.2014.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/18/2014] [Accepted: 07/22/2014] [Indexed: 12/31/2022]
Abstract
Thymic epithelial cells (TEC) and dendritic cells (DC) play a role in T cell development by controlling the selection of the T cell receptor repertoire. DC have been described to take up antigens in the periphery and migrate into the thymus where they mediate tolerance via deletion of autoreactive T cells, or by induction of natural regulatory T cells. Migration of DC to thymus is driven by chemokine receptors. CCL2, a major ligand for the chemokine receptor CCR2, is an inflammation-associated chemokine that induces the recruitment of immune cells in tissues. CCL2 and CCR2 are implicated in promoting experimental autoimmune encephalomyelitis (EAE), a mouse model for multiple sclerosis. We here show that CCL2 is constitutively expressed by endothelial cells and TEC in the thymus. Transgenic mice overexpressing CCL2 in the thymus showed an increased number of thymic plasmacytoid DC and pronounced impairment of T cell development. Consequently, CCL2 transgenic mice were resistant to EAE. These findings demonstrate that expression of CCL2 in thymus regulates DC homeostasis and controls development of autoreactive T cells, thus preventing development of autoimmune diseases.
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Affiliation(s)
- O Cédile
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, DK-5000 Odense C, Denmark
| | - M Løbner
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, DK-5000 Odense C, Denmark
| | - H Toft-Hansen
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, DK-5000 Odense C, Denmark
| | - I Frank
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, DK-5000 Odense C, Denmark
| | - A Wlodarczyk
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, DK-5000 Odense C, Denmark
| | - M Irla
- Centre d'Immunologie de Marseille-Luminy - CIML, Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique, UMR7280 and Aix Marseille Université, UM2, F-13009 Marseille, France
| | - T Owens
- Institute of Molecular Medicine, Department of Neurobiology Research, University of Southern Denmark, J.B. Winsløwsvej 25, DK-5000 Odense C, Denmark.
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Pickell L, Wu Q, Wang XL, Leclerc D, Friedman H, Peterson AC, Rozen R. Targeted insertion of two Mthfr promoters in mice reveals temporal- and tissue-specific regulation. Mamm Genome 2011; 22:635-47. [PMID: 21769670 DOI: 10.1007/s00335-011-9351-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 06/07/2011] [Indexed: 11/30/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, synthesizes 5-methyltetrahydrofolate, the main circulatory form of folate which is required for maintaining nontoxic levels of homocysteine and providing one-carbon units for methylation. A common 677C → T variant in MTHFR confers mild MTHFR deficiency and has been associated with a number of human disorders, including neural tube defects and vascular disease. Two promoters of Mthfr, designated as upstream and downstream promoters, are located upstream of a transcription start site cluster and have previously demonstrated cell-specific activities. In this study we used a unique approach for targeted, single-copy transgene insertion to generate transgenic mice carrying a Mthfr upstream or Mthfr downstream promoter-reporter construct located 5' to the endogenous Hprt (hypoxanthine-guanine phosphoribosyltransferase) locus. The Mthfr downstream promoter demonstrated activity in the neural tube, neural crest cells, dorsal root ganglia, heart, and endothelial cells of blood vessels in 10.5-days post coitum embryos and placentas. Upstream promoter activity was absent at this developmental stage. Postnatally, both promoters demonstrated activity in the brain stem, hippocampus, and thalamus of 1-week-old brain that became stronger in the adult. The Mthfr upstream promoter also showed activity in the cerebellum and cerebral cortex. Both promoters were active in male reproductive tissues, including 1-week-old epididymides, and there was upstream promoter-specific activity in the adult testis. Our investigation of Mthfr regulation in an in vivo mouse model revealed temporal- and tissue-specific regulation that supports important roles for MTHFR in the developing embryo, and in postnatal brain and male reproductive tissues.
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Affiliation(s)
- Laura Pickell
- Departments of Human Genetics and Pediatrics, McGill University and Montreal Children's Hospital Research Institute, Montreal, QC, Canada
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Fulton DL, Denarier E, Friedman HC, Wasserman WW, Peterson AC. Towards resolving the transcription factor network controlling myelin gene expression. Nucleic Acids Res 2011; 39:7974-91. [PMID: 21729871 PMCID: PMC3185407 DOI: 10.1093/nar/gkr326] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In the central nervous system (CNS), myelin is produced from spirally-wrapped oligodendrocyte plasma membrane and, as exemplified by the debilitating effects of inherited or acquired myelin abnormalities in diseases such as multiple sclerosis, it plays a critical role in nervous system function. Myelin sheath production coincides with rapid up-regulation of numerous genes. The complexity of their subsequent expression patterns, along with recently recognized heterogeneity within the oligodendrocyte lineage, suggest that the regulatory networks controlling such genes drive multiple context-specific transcriptional programs. Conferring this nuanced level of control likely involves a large repertoire of interacting transcription factors (TFs). Here, we combined novel strategies of computational sequence analyses with in vivo functional analysis to establish a TF network model of coordinate myelin-associated gene transcription. Notably, the network model captures regulatory DNA elements and TFs known to regulate oligodendrocyte myelin gene transcription and/or oligodendrocyte development, thereby validating our approach. Further, it links to numerous TFs with previously unsuspected roles in CNS myelination and suggests collaborative relationships amongst both known and novel TFs, thus providing deeper insight into the myelin gene transcriptional network.
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Affiliation(s)
- Debra L Fulton
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, V5Z 4H4, Canada
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