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Makwana R, Christ C, Marchi E, Harpell R, Lyon GJ. Longitudinal Adaptive Behavioral Outcomes in Ogden Syndrome by Seizure Status and Therapeutic Intervention. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.23.24303144. [PMID: 38585745 PMCID: PMC10996826 DOI: 10.1101/2024.02.23.24303144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Ogden syndrome, also known as NAA10-related neurodevelopmental syndrome, is a rare genetic condition associated with pathogenic variants in the NAA10 N-terminal acetylation family of proteins. The condition was initially described in 2011, and is characterized by a range of neurologic symptoms, including intellectual disability and seizures, as well as developmental delays, psychiatric symptoms, congenital heart abnormalities, hypotonia and others. Previously published articles have described the etiology and phenotype of Ogden syndrome, mostly with retrospective analyses; herein, we report prospective data concerning its progress over time. Additionally, we describe the nature of seizures in this condition in greater detail, as well as investigate how already-available non-pharmaceutical therapies impact individuals with NAA10-related neurodevelopmental syndrome. Using Vineland-3 scores, we show decline in cognitive function over time in individuals with Ogden syndrome. Sub-domain analysis found the decline to be present across all modalities. Additional investigation between seizure and non-seizure groups showed no significant difference in adaptive behavior outcomes. Therapy investigation showed speech therapy to be the most commonly used therapy by individuals with NAA10-related neurodevelopmental syndrome, followed by occupational and physical therapy. with more severely affected individuals receiving more types of therapy than their less-severe counterparts. Early intervention analysis was only significantly effective for speech therapy, with analyses of all other therapies being non-significant. Our study portrays the decline in cognitive function over time of individuals within our cohort, independent of seizure status and therapies being received, and highlights the urgent need for the development of effective treatments for Ogden syndrome.
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Affiliation(s)
- Rikhil Makwana
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Carolina Christ
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Elaine Marchi
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Randie Harpell
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
| | - Gholson J. Lyon
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
- George A. Jervis Clinic, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, United States of America
- Biology PhD Program, The Graduate Center, The City University of New York, New York, United States of America
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2
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Pramanik S, Bala A, Pradhan A. Zebrafish in understanding molecular pathophysiology, disease modeling, and developing effective treatments for Rett syndrome. J Gene Med 2024; 26:e3677. [PMID: 38380785 DOI: 10.1002/jgm.3677] [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: 11/14/2023] [Revised: 01/04/2024] [Accepted: 01/28/2024] [Indexed: 02/22/2024] Open
Abstract
Rett syndrome (RTT) is a rare but dreadful X-linked genetic disease that mainly affects young girls. It is a neurological disease that affects nerve cell development and function, resulting in severe motor and intellectual disabilities. To date, no cure is available for treating this disease. In 90% of the cases, RTT is caused by a mutation in methyl-CpG-binding protein 2 (MECP2), a transcription factor involved in the repression and activation of transcription. MECP2 is known to regulate several target genes and is involved in different physiological functions. Mouse models exhibit a broad range of phenotypes in recapitulating human RTT symptoms; however, understanding the disease mechanisms remains incomplete, and many potential RTT treatments developed in mouse models have not shown translational effectiveness in human trials. Recent data hint that the zebrafish model emulates similar disrupted neurological functions following mutation of the mecp2 gene. This suggests that zebrafish can be used to understand the onset and progression of RTT pathophysiology and develop a possible cure. In this review, we elaborate on the molecular basis of RTT pathophysiology in humans and model organisms, including rodents and zebrafish, focusing on the zebrafish model to understand the molecular pathophysiology and the development of therapeutic strategies for RTT. Finally, we propose a rational treatment strategy, including antisense oligonucleotides, small interfering RNA technology and induced pluripotent stem cell-derived cell therapy.
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Affiliation(s)
- Subrata Pramanik
- Jyoti and Bhupat Mehta School of Health Sciences and Technology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Asis Bala
- Pharmacology and Drug Discovery Research Laboratory, Division of Life Sciences; Institute of Advanced Study in Science and Technology (IASST), An Autonomous Institute Under - Department of Science & Technology (Govt. of India) Vigyan Path, Guwahati, Assam, India
| | - Ajay Pradhan
- Biology, The Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden
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3
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Johansson J, Lidéus S, Höijer I, Ameur A, Gudmundsson S, Annerén G, Bondeson ML, Wilbe M. A novel quantitative targeted analysis of X-chromosome inactivation (XCI) using nanopore sequencing. Sci Rep 2023; 13:12856. [PMID: 37553382 PMCID: PMC10409790 DOI: 10.1038/s41598-023-34413-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 04/29/2023] [Indexed: 08/10/2023] Open
Abstract
X-chromosome inactivation (XCI) analyses often assist in diagnostics of X-linked traits, however accurate assessment remains challenging with current methods. We developed a novel strategy using amplification-free Cas9 enrichment and Oxford nanopore technologies sequencing called XCI-ONT, to investigate and rigorously quantify XCI in human androgen receptor gene (AR) and human X-linked retinitis pigmentosa 2 gene (RP2). XCI-ONT measures methylation over 116 CpGs in AR and 58 CpGs in RP2, and separate parental X-chromosomes without PCR bias. We show the usefulness of the XCI-ONT strategy over the PCR-based golden standard XCI technique that only investigates one or two CpGs per gene. The results highlight the limitations of using the golden standard technique when the XCI pattern is partially skewed and the advantages of XCI-ONT to rigorously quantify XCI. This study provides a universal XCI-method on DNA, which is highly valuable in clinical and research framework of X-linked traits.
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Affiliation(s)
- Josefin Johansson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Sarah Lidéus
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Ida Höijer
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Adam Ameur
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Sanna Gudmundsson
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Göran Annerén
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Marie-Louise Bondeson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Maria Wilbe
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden.
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4
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Oluigbo DC. Rett Syndrome: A Tale of Altered Genetics, Synaptic Plasticity, and Neurodevelopmental Dynamics. Cureus 2023; 15:e41555. [PMID: 37554594 PMCID: PMC10405636 DOI: 10.7759/cureus.41555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2023] [Indexed: 08/10/2023] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder that is a leading cause of severe cognitive and physical impairment. RTT typically occurs in females, although rare cases of males with the disease exist. Its genetic cause, symptoms, and clinical progression timeline have also become well-documented since its initial discovery. However, a relatively late diagnosis and lack of an available cure signify that our understanding of the disease is incomplete. Innovative research methods and tools are thereby helping to fill gaps in our knowledge of RTT. Specifically, mouse models of RTT, video analysis, and retrospective parental analysis are well-established tools that provide valuable insights into RTT. Moreover, current and anticipated treatment options are improving the quality of life of the RTT patient population. Collectively, these developments are creating optimistic future perspectives for RTT.
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Affiliation(s)
- David C Oluigbo
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, USA
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5
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Palmieri M, Pozzer D, Landsberger N. Advanced genetic therapies for the treatment of Rett syndrome: state of the art and future perspectives. Front Neurosci 2023; 17:1172805. [PMID: 37304036 PMCID: PMC10248472 DOI: 10.3389/fnins.2023.1172805] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Loss and gain of functions mutations in the X-linked MECP2 (methyl-CpG-binding protein 2) gene are responsible for a set of generally severe neurological disorders that can affect both genders. In particular, Mecp2 deficiency is mainly associated with Rett syndrome (RTT) in girls, while duplication of the MECP2 gene leads, mainly in boys, to the MECP2 duplication syndrome (MDS). No cure is currently available for MECP2 related disorders. However, several studies have reported that by re-expressing the wild-type gene is possible to restore defective phenotypes of Mecp2 null animals. This proof of principle endorsed many laboratories to search for novel therapeutic strategies to cure RTT. Besides pharmacological approaches aimed at modulating MeCP2-downstream pathways, genetic targeting of MECP2 or its transcript have been largely proposed. Remarkably, two studies focused on augmentative gene therapy were recently approved for clinical trials. Both use molecular strategies to well-control gene dosage. Notably, the recent development of genome editing technologies has opened an alternative way to specifically target MECP2 without altering its physiological levels. Other attractive approaches exclusively applicable for nonsense mutations are the translational read-through (TR) and t-RNA suppressor therapy. Reactivation of the MECP2 locus on the silent X chromosome represents another valid choice for the disease. In this article, we intend to review the most recent genetic interventions for the treatment of RTT, describing the current state of the art, and the related advantages and concerns. We will also discuss the possible application of other advanced therapies, based on molecular delivery through nanoparticles, already proposed for other neurological disorders but still not tested in RTT.
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Affiliation(s)
- Michela Palmieri
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Diego Pozzer
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Nicoletta Landsberger
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Faculty of Medicine and Surgery, University of Milan, Milan, Italy
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6
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Nickbarg EB, Spencer KB, Mortison JD, Lee JT. Targeting RNA with small molecules: lessons learned from Xist RNA. RNA (NEW YORK, N.Y.) 2023; 29:463-472. [PMID: 36725318 PMCID: PMC10019374 DOI: 10.1261/rna.079523.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Although more than 98% of the human genome is noncoding, nearly all drugs on the market target one of about 700 disease-related proteins. However, an increasing number of diseases are now being attributed to noncoding RNA and the ability to target them would vastly expand the chemical space for drug development. We recently devised a screening strategy based upon affinity-selection mass spectrometry and succeeded in identifying bioactive compounds for the noncoding RNA prototype, Xist. One such compound, termed X1, has drug-like properties and binds specifically to the RepA motif of Xist in vitro and in vivo. Small-angle X-ray scattering analysis reveals that X1 changes the conformation of RepA in solution, thereby explaining the displacement of cognate interacting protein factors (PRC2 and SPEN) and inhibition of X-chromosome inactivation. In this Perspective, we discuss lessons learned from these proof-of-concept experiments and suggest that RNA can be systematically targeted by drug-like compounds to disrupt RNA structure and function.
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Affiliation(s)
| | | | | | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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7
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Panayotis N, Ehinger Y, Felix MS, Roux JC. State-of-the-art therapies for Rett syndrome. Dev Med Child Neurol 2023; 65:162-170. [PMID: 36056801 PMCID: PMC10087176 DOI: 10.1111/dmcn.15383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 01/04/2023]
Abstract
Rett syndrome (RTT) is an X-linked neurogenetic disorder caused by mutations of the MECP2 (methyl-CpG-binding protein 2) gene. Over two decades of work established MeCP2 as a protein with pivotal roles in the regulation of the epigenome, neuronal physiology, synaptic maintenance, and behaviour. Given the genetic aetiology of RTT and the proof of concept of its reversal in a mouse model, considerable efforts have been made to design therapeutic approaches to re-express MeCP2. By being at the forefront of the development of innovative gene therapies, research on RTT is of paramount importance for the treatment of monogenic neurological diseases. Here we discuss the recent advances and challenges of promising genetic strategies for the treatment of RTT including gene replacement therapies, gene/RNA editing strategies, and reactivation of the silenced X chromosome. WHAT THIS PAPER ADDS: Recent advances shed light on the promises of gene replacement therapy with new vectors designed to control the levels of MeCP2 expression. New developments in DNA/RNA editing approaches or reactivation of the silenced X chromosome open the possibility to re-express the native MeCP2 locus at endogenous levels. Current strategies still face limitations in transduction efficiency and future work is needed to improve brain delivery.
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Affiliation(s)
- Nicolas Panayotis
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.,Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel.,Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Yann Ehinger
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
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8
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Grimm NB, Lee JT. Selective Xi reactivation and alternative methods to restore MECP2 function in Rett syndrome. Trends Genet 2022; 38:920-943. [PMID: 35248405 PMCID: PMC9915138 DOI: 10.1016/j.tig.2022.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
The human X-chromosome harbors only 4% of our genome but carries over 20% of genes associated with intellectual disability. Given that they inherit only one X-chromosome, males are more frequently affected by X-linked neurodevelopmental genetic disorders than females. However, despite inheriting two X-chromosomes, females can also be affected because X-chromosome inactivation enables only one of two X-chromosomes to be expressed per cell. For Rett syndrome and similar X-linked disorders affecting females, disease-specific treatments have remained elusive. However, a cure may be found within their own cells because every sick cell carries a healthy copy of the affected gene on the inactive X (Xi). Therefore, selective Xi reactivation may be a viable approach that would address the root cause of various X-linked disorders. Here, we discuss Rett syndrome and compare current approaches in the pharmaceutical pipeline to restore MECP2 function. We then focus on Xi reactivation and review available methods, lessons learned, and future directions.
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Affiliation(s)
- Niklas-Benedikt Grimm
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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9
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XIST loss impairs mammary stem cell differentiation and increases tumorigenicity through Mediator hyperactivation. Cell 2022; 185:2164-2183.e25. [PMID: 35597241 DOI: 10.1016/j.cell.2022.04.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 01/10/2022] [Accepted: 04/27/2022] [Indexed: 12/27/2022]
Abstract
X inactivation (XCI) is triggered by upregulation of XIST, which coats the chromosome in cis, promoting formation of a heterochromatic domain (Xi). XIST role beyond initiation of XCI is only beginning to be elucidated. Here, we demonstrate that XIST loss impairs differentiation of human mammary stem cells (MaSCs) and promotes emergence of highly tumorigenic and metastatic carcinomas. On the Xi, XIST deficiency triggers epigenetic changes and reactivation of genes overlapping Polycomb domains, including Mediator subunit MED14. MED14 overdosage results in increased Mediator levels and hyperactivation of the MaSC enhancer landscape and transcriptional program, making differentiation less favorable. We further demonstrate that loss of XIST and Xi transcriptional instability is common among human breast tumors of poor prognosis. We conclude that XIST is a gatekeeper of human mammary epithelium homeostasis, thus unveiling a paradigm in the control of somatic cell identity with potential consequences for our understanding of gender-specific malignancies.
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10
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BAF complex-mediated chromatin relaxation is required for establishment of X chromosome inactivation. Nat Commun 2022; 13:1658. [PMID: 35351876 PMCID: PMC8964718 DOI: 10.1038/s41467-022-29333-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/10/2022] [Indexed: 12/12/2022] Open
Abstract
The process of epigenetic silencing, while fundamentally important, is not yet completely understood. Here we report a replenishable female mouse embryonic stem cell (mESC) system, Xmas, that allows rapid assessment of X chromosome inactivation (XCI), the epigenetic silencing mechanism of one of the two X chromosomes that enables dosage compensation in female mammals. Through a targeted genetic screen in differentiating Xmas mESCs, we reveal that the BAF complex is required to create nucleosome-depleted regions at promoters on the inactive X chromosome during the earliest stages of establishment of XCI. Without this action gene silencing fails. Xmas mESCs provide a tractable model for screen-based approaches that enable the discovery of unknown facets of the female-specific process of XCI and epigenetic silencing more broadly. Female embryonic stem cells (ESCs) are the ideal model to study X chromosome inactivation (XCI) establishment; however, these cells are challenging to keep in culture. Here the authors create fluorescent ‘Xmas’ reporter mice as a renewable source of ESCs and show nucleosome remodelers Smarcc1 and Smarca4 create a nucleosome-free promoter region prior to the establishment of silencing.
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11
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Mira-Bontenbal H, Tan B, Gontan C, Goossens S, Boers RG, Boers JB, Dupont C, van Royen ME, IJcken WFJ, French P, Bedalov A, Gribnau J. Genetic and epigenetic determinants of reactivation of Mecp2 and the inactive X chromosome in neural stem cells. Stem Cell Reports 2022; 17:693-706. [PMID: 35148843 PMCID: PMC9039756 DOI: 10.1016/j.stemcr.2022.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 01/17/2023] Open
Abstract
Rett syndrome may be treated by reactivating the silent copy of Mecp2 from the inactive X chromosome in female cells. Most studies that model Mecp2 reactivation have used mouse fibroblasts rather than neural cells, which would be critical for phenotypic reversal, and rely on fluorescent reporters that lack adequate sensitivity. Here, we present a mouse model based on a dual bioluminescent and fluorescent reporter to assess the level of reactivation of Mecp2 and the inactive X chromosome by treating neural stem cells with 5-azacytidine and Xist knockdown. We show that reactivation of Mecp2 and other X-linked genes correlates with CpG density, with distance from escapees, and, very strongly, with the presence of short interspersed nuclear elements. In addition, X-linked genes reactivated in neural stem cells overlap substantially with early reactivating genes by induced pluripotent stem cell reprogramming of fibroblasts or neuronal progenitors, indicating that X chromosome reactivation follows similar paths regardless of the technique or cell type used.
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Affiliation(s)
- H Mira-Bontenbal
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands.
| | - B Tan
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands
| | - C Gontan
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands
| | - S Goossens
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands
| | - R G Boers
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands
| | - J B Boers
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands
| | - C Dupont
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands
| | - M E van Royen
- Department of Pathology, Erasmus MC, Rotterdam, the Netherlands
| | - W F J IJcken
- Center for Biomics, Department of Cell Biology, Erasmus MC, Rotterdam, the Netherlands
| | - P French
- Department of Neurology, Erasmus MC Cancer Institute, University Medical Center, Rotterdam, the Netherlands
| | - A Bedalov
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA 98109, USA
| | - J Gribnau
- Oncode Institue, Department of Developmental Biology, Erasmus MC, Rotterdam, the Netherlands.
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12
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Gjaltema RAF, Schwämmle T, Kautz P, Robson M, Schöpflin R, Ravid Lustig L, Brandenburg L, Dunkel I, Vechiatto C, Ntini E, Mutzel V, Schmiedel V, Marsico A, Mundlos S, Schulz EG. Distal and proximal cis-regulatory elements sense X chromosome dosage and developmental state at the Xist locus. Mol Cell 2022; 82:190-208.e17. [PMID: 34932975 DOI: 10.1016/j.molcel.2021.11.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/15/2022]
Abstract
Developmental genes such as Xist, which initiates X chromosome inactivation, are controlled by complex cis-regulatory landscapes, which decode multiple signals to establish specific spatiotemporal expression patterns. Xist integrates information on X chromosome dosage and developmental stage to trigger X inactivation in the epiblast specifically in female embryos. Through a pooled CRISPR screen in differentiating mouse embryonic stem cells, we identify functional enhancer elements of Xist at the onset of random X inactivation. Chromatin profiling reveals that X-dosage controls the promoter-proximal region, while differentiation cues activate several distal enhancers. The strongest distal element lies in an enhancer cluster associated with a previously unannotated Xist-enhancing regulatory transcript, which we named Xert. Developmental cues and X-dosage are thus decoded by distinct regulatory regions, which cooperate to ensure female-specific Xist upregulation at the correct developmental time. With this study, we start to disentangle how multiple, functionally distinct regulatory elements interact to generate complex expression patterns in mammals.
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Affiliation(s)
- Rutger A F Gjaltema
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Till Schwämmle
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Pauline Kautz
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Michael Robson
- Development and Disease Group, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh EH4 2XU, Edinburgh, UK
| | - Robert Schöpflin
- Development and Disease Group, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany; Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Liat Ravid Lustig
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Lennart Brandenburg
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Ilona Dunkel
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Carolina Vechiatto
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Evgenia Ntini
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Verena Mutzel
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Vera Schmiedel
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Annalisa Marsico
- Computational Health Center, Helmholtz Center München, 85764 Neuherberg, Germany
| | - Stefan Mundlos
- Development and Disease Group, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Edda G Schulz
- Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany.
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13
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X-chromosome reactivation: a concise review. Biochem Soc Trans 2021; 49:2797-2805. [PMID: 34821360 DOI: 10.1042/bst20210777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 12/14/2022]
Abstract
Mammalian females (XX) silence transcription on one of the two X chromosomes to compensate the expression dosage with males (XY). This process - named X-chromosome inactivation - entails a variety of epigenetic modifications that act synergistically to maintain silencing and make it heritable through cell divisions. Genes along the inactive X chromosome are, indeed, refractory to reactivation. Nonetheless, X-chromosome reactivation can occur alongside with epigenome reprogramming or by perturbing multiple silencing pathways. Here we review the events associated with X-chromosome reactivation during in vivo and in vitro reprogramming and highlight recent efforts in inducing Xi reactivation by molecular perturbations. This provides us with a first understanding of the mechanisms underlying X-chromosome reactivation, which could be tackled for therapeutic purposes.
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14
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Villani C, Carli M, Castaldo AM, Sacchetti G, Invernizzi RW. Fluoxetine increases brain MeCP2 immuno-positive cells in a female Mecp2 heterozygous mouse model of Rett syndrome through endogenous serotonin. Sci Rep 2021; 11:14690. [PMID: 34282222 PMCID: PMC8290043 DOI: 10.1038/s41598-021-94156-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 07/07/2021] [Indexed: 12/12/2022] Open
Abstract
Motor skill deficit is a common and invalidating symptom of Rett syndrome (RTT), a rare disease almost exclusively affecting girls during the first/second year of life. Loss-of-function mutations of the methyl-CpG-binding protein2 (MECP2; Mecp2 in rodents) gene is the cause in most patients. We recently found that fluoxetine, a selective serotonin (5-HT) reuptake inhibitor and antidepressant drug, fully rescued motor coordination deficits in Mecp2 heterozygous (Mecp2 HET) mice acting through brain 5-HT. Here, we asked whether fluoxetine could increase MeCP2 expression in the brain of Mecp2 HET mice, under the same schedule of treatment improving motor coordination. Fluoxetine increased the number of MeCP2 immuno-positive (MeCP2+) cells in the prefrontal cortex, M1 and M2 motor cortices, and in dorsal, ventral and lateral striatum. Fluoxetine had no effect in the CA3 region of the hippocampus or in any of the brain regions of WT mice. Inhibition of 5-HT synthesis abolished the fluoxetine-induced rise of MeCP2+ cells. These findings suggest that boosting 5-HT transmission is sufficient to enhance the expression of MeCP2 in several brain regions of Mecp2 HET mice. Fluoxetine-induced rise of MeCP2 could potentially rescue motor coordination and other deficits of RTT.
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Affiliation(s)
- Claudia Villani
- Laboratory Neurochemistry and Behavior, Neuroscience Department, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156, Milan, Italy
| | - Mirjana Carli
- Laboratory Neurochemistry and Behavior, Neuroscience Department, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156, Milan, Italy
| | - Anna Maria Castaldo
- Laboratory Neurochemistry and Behavior, Neuroscience Department, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156, Milan, Italy
| | - Giuseppina Sacchetti
- Laboratory Neurochemistry and Behavior, Neuroscience Department, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156, Milan, Italy
| | - Roberto William Invernizzi
- Laboratory Neurochemistry and Behavior, Neuroscience Department, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156, Milan, Italy.
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15
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Yu B, Qi Y, Li R, Shi Q, Satpathy AT, Chang HY. B cell-specific XIST complex enforces X-inactivation and restrains atypical B cells. Cell 2021; 184:1790-1803.e17. [PMID: 33735607 DOI: 10.1016/j.cell.2021.02.015] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/07/2020] [Accepted: 02/04/2021] [Indexed: 12/16/2022]
Abstract
The long non-coding RNA (lncRNA) XIST establishes X chromosome inactivation (XCI) in female cells in early development and thereafter is thought to be largely dispensable. Here, we show XIST is continually required in adult human B cells to silence a subset of X-linked immune genes such as TLR7. XIST-dependent genes lack promoter DNA methylation and require continual XIST-dependent histone deacetylation. XIST RNA-directed proteomics and CRISPRi screen reveal distinctive somatic cell-type-specific XIST complexes and identify TRIM28 that mediates Pol II pausing at promoters of X-linked genes in B cells. Single-cell transcriptome data of female patients with either systemic lupus erythematosus or COVID-19 infection revealed XIST dysregulation, reflected by escape of XIST-dependent genes, in CD11c+ atypical memory B cells (ABCs). XIST inactivation with TLR7 agonism suffices to promote isotype-switched ABCs. These results indicate cell-type-specific diversification and function for lncRNA-protein complexes and suggest expanded roles for XIST in sex-differences in biology and medicine.
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Affiliation(s)
- Bingfei Yu
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA 94305, USA
| | - Yanyan Qi
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA 94305, USA
| | - Rui Li
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA 94305, USA
| | - Quanming Shi
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA 94305, USA
| | | | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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16
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Yu B, Qi Y, Li R, Shi Q, Satpathy A, Chang HY. B cell-specific XIST complex enforces X-inactivation and restrains atypical B cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021. [PMID: 33442682 PMCID: PMC7805439 DOI: 10.1101/2021.01.03.425167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The long noncoding RNA (lncRNA) XIST establishes X chromosome inactivation (XCI) in female cells in early development and thereafter is thought to be largely dispensable. Here we show XIST is continually required in adult human B cells to silence a subset of X-linked immune genes such as TLR7 . XIST-dependent genes lack promoter DNA methylation and require continual XIST-dependent histone deacetylation. XIST RNA-directed proteomics and CRISPRi screen reveal distinctive somatic cell-specific XIST complexes, and identify TRIM28 that mediates Pol II pausing at promoters of X-linked genes in B cells. XIST dysregylation, reflected by escape of XIST-dependent genes, occurs in CD11c+ atypical memory B cells across single-cell transcriptome data in patients with female-biased autoimmunity and COVID-19 infection. XIST inactivation with TLR7 agonism suffices to promote isotype-switched atypical B cells. These results suggest cell-type-specific diversification of lncRNA-protein complexes increase lncRNA functionalities, and expand roles for XIST in sex-differences in biology and medicine. HIGHLIGHTS XIST prevents escape of genes with DNA hypomethylated promoters in B cells.XIST maintains X-inactivation through continuous deacetylation of H3K27ac.XIST ChIRP-MS and allelic CRISPRi screen reveal a B cell-specific XIST cofactor TRIM28.XIST loss and TLR7 stimulation promotes CD11c+ atypical B cell formation.
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17
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Panda A, Zylicz JJ, Pasque V. New Insights into X-Chromosome Reactivation during Reprogramming to Pluripotency. Cells 2020; 9:E2706. [PMID: 33348832 PMCID: PMC7766869 DOI: 10.3390/cells9122706] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023] Open
Abstract
Dosage compensation between the sexes results in one X chromosome being inactivated during female mammalian development. Chromosome-wide transcriptional silencing from the inactive X chromosome (Xi) in mammalian cells is erased in a process termed X-chromosome reactivation (XCR), which has emerged as a paradigm for studying the reversal of chromatin silencing. XCR is linked with germline development and induction of naive pluripotency in the epiblast, and also takes place upon reprogramming somatic cells to induced pluripotency. XCR depends on silencing of the long non-coding RNA (lncRNA) X inactive specific transcript (Xist) and is linked with the erasure of chromatin silencing. Over the past years, the advent of transcriptomics and epigenomics has provided new insights into the transcriptional and chromatin dynamics with which XCR takes place. However, multiple questions remain unanswered about how chromatin and transcription related processes enable XCR. Here, we review recent work on establishing the transcriptional and chromatin kinetics of XCR, as well as discuss a model by which transcription factors mediate XCR not only via Xist repression, but also by direct targeting of X-linked genes.
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Affiliation(s)
- Amitesh Panda
- Laboratory of Cellular Reprogramming and Epigenetic Regulation, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven-University of Leuven, 3000 Leuven, Belgium;
| | - Jan J. Zylicz
- The Novo Nordisk Foundation Center for Stem Cell Biology, University of Copenhagen, 2200 Copenhagen, Denmark;
| | - Vincent Pasque
- Laboratory of Cellular Reprogramming and Epigenetic Regulation, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven-University of Leuven, 3000 Leuven, Belgium;
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18
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Lee HM, Kuijer MB, Ruiz Blanes N, Clark EP, Aita M, Galiano Arjona L, Kokot A, Sciaky N, Simon JM, Bhatnagar S, Philpot BD, Cerase A. A small-molecule screen reveals novel modulators of MeCP2 and X-chromosome inactivation maintenance. J Neurodev Disord 2020; 12:29. [PMID: 33172406 PMCID: PMC7657357 DOI: 10.1186/s11689-020-09332-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 10/22/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked methyl-CpG binding protein 2 (MeCP2) gene. While MeCP2 mutations are lethal in most males, females survive birth but show severe neurological defects. Because X-chromosome inactivation (XCI) is a random process, approximately 50% of the cells silence the wild-type (WT) copy of the MeCP2 gene. Thus, reactivating the silent WT copy of MeCP2 could provide therapeutic intervention for RTT. METHODS Toward this goal, we screened ~ 28,000 small-molecule compounds from several libraries using a MeCP2-luciferase reporter cell line and cortical neurons from a MeCP2-EGFP mouse model. We used gain/increase of luminescence or fluorescence as a readout of MeCP2 reactivation and tested the efficacy of these drugs under different drug regimens, conditions, and cellular contexts. RESULTS We identified inhibitors of the JAK/STAT pathway as XCI-reactivating agents, both by in vitro and ex vivo assays. In particular, we show that AG-490, a Janus Kinase 2 (JAK2) kinase inhibitor, and Jaki, a pan JAK/STAT inhibitor, are capable of reactivating MeCP2 from the inactive X chromosome, in different cellular contexts. CONCLUSIONS Our results suggest that inhibition of the JAK/STAT pathway is a new potential pathway to reinstate MeCP2 gene expression as an efficient RTT treatment.
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Affiliation(s)
- Hyeong-Min Lee
- Department of Cell Biology & Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- UNC Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- Current Address: High-Throughput Bioscience Center, Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - M Bram Kuijer
- Department of Cell Biology & Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | | | - Ellen P Clark
- Department of Cell Biology & Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Megumi Aita
- Department of Cell Biology & Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | | | - Agnieszka Kokot
- Department of Biochemistry and Molecular Genetics, Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Noah Sciaky
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jeremy M Simon
- UNC Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Sanchita Bhatnagar
- Department of Biochemistry and Molecular Genetics, Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Benjamin D Philpot
- Department of Cell Biology & Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- UNC Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Andrea Cerase
- Blizard Institute, Queen Mary University of London, London, UK.
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19
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Bonnycastle K, Davenport EC, Cousin MA. Presynaptic dysfunction in neurodevelopmental disorders: Insights from the synaptic vesicle life cycle. J Neurochem 2020; 157:179-207. [PMID: 32378740 DOI: 10.1111/jnc.15035] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022]
Abstract
The activity-dependent fusion, retrieval and recycling of synaptic vesicles is essential for the maintenance of neurotransmission. Until relatively recently it was believed that most mutations in genes that were essential for this process would be incompatible with life, because of this fundamental role. However, an ever-expanding number of mutations in this very cohort of genes are being identified in individuals with neurodevelopmental disorders, including autism, intellectual disability and epilepsy. This article will summarize the current state of knowledge linking mutations in presynaptic genes to neurodevelopmental disorders by sequentially covering the various stages of the synaptic vesicle life cycle. It will also discuss how perturbations of specific stages within this recycling process could translate into human disease. Finally, it will also provide perspectives on the potential for future therapy that are targeted to presynaptic function.
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Affiliation(s)
- Katherine Bonnycastle
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
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20
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Xist Repeats A and B Account for Two Distinct Phases of X Inactivation Establishment. Dev Cell 2020; 54:21-32.e5. [PMID: 32531209 DOI: 10.1016/j.devcel.2020.05.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 02/16/2020] [Accepted: 05/14/2020] [Indexed: 11/20/2022]
Abstract
X chromosome inactivation (XCI) is a global silencing mechanism by which XX and XY mammals equalize X-linked gene dosages. XCI begins with an establishment phase during which Xist RNA spreads and induces de novo heterochromatinization across a female X chromosome and is followed by a maintenance phase when multiple epigenetic pathways lock down the inactive X (Xi) state. Involvement of Polycomb repressive complexes 1 and 2 in XCI has been intensively studied but with conflicting conclusions regarding their recruitment and role in Xi silencing. Here, we reveal that establishment of XCI has two phases and reconcile the roles that Xist repeats A and B play in gene silencing and Polycomb recruitment. Repeat A initiates both processes, whereas repeat B bolsters or stabilizes them thereafter. Once established, XCI no longer requires repeat A during maintenance. These findings integrate disparate studies and present a unified view of Xist's role in Polycomb-mediated silencing.
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21
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Halmai JANM, Deng P, Gonzalez CE, Coggins NB, Cameron D, Carter JL, Buchanan FKB, Waldo JJ, Lock SR, Anderson JD, O’Geen H, Segal DJ, Nolta J, Fink KD. Artificial escape from XCI by DNA methylation editing of the CDKL5 gene. Nucleic Acids Res 2020; 48:2372-2387. [PMID: 31925439 PMCID: PMC7049732 DOI: 10.1093/nar/gkz1214] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 12/13/2019] [Accepted: 12/18/2019] [Indexed: 12/29/2022] Open
Abstract
A significant number of X-linked genes escape from X chromosome inactivation and are associated with a distinct epigenetic signature. One epigenetic modification that strongly correlates with X-escape is reduced DNA methylation in promoter regions. Here, we created an artificial escape by editing DNA methylation on the promoter of CDKL5, a gene causative for an infantile epilepsy, from the silenced X-chromosomal allele in human neuronal-like cells. We identify that a fusion of the catalytic domain of TET1 to dCas9 targeted to the CDKL5 promoter using three guide RNAs causes significant reactivation of the inactive allele in combination with removal of methyl groups from CpG dinucleotides. Strikingly, we demonstrate that co-expression of TET1 and a VP64 transactivator have a synergistic effect on the reactivation of the inactive allele to levels >60% of the active allele. We further used a multi-omics assessment to determine potential off-targets on the transcriptome and methylome. We find that synergistic delivery of dCas9 effectors is highly selective for the target site. Our findings further elucidate a causal role for reduced DNA methylation associated with escape from X chromosome inactivation. Understanding the epigenetics associated with escape from X chromosome inactivation has potential for those suffering from X-linked disorders.
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MESH Headings
- Alleles
- CRISPR-Associated Protein 9/genetics
- CRISPR-Associated Protein 9/metabolism
- Catalytic Domain
- Cell Line, Tumor
- Chromosomes, Human, X/chemistry
- Chromosomes, Human, X/metabolism
- CpG Islands
- Epigenesis, Genetic
- Gene Editing
- Gene Silencing
- Humans
- Mixed Function Oxygenases/genetics
- Mixed Function Oxygenases/metabolism
- Neurons/cytology
- Neurons/metabolism
- Promoter Regions, Genetic
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Trans-Activators/genetics
- Trans-Activators/metabolism
- X Chromosome Inactivation
- RNA, Guide, CRISPR-Cas Systems
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Affiliation(s)
- Julian A N M Halmai
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Peter Deng
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
- Genome Center and Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA
| | - Casiana E Gonzalez
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Nicole B Coggins
- Genome Center and Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA
| | - David Cameron
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Jasmine L Carter
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Fiona K B Buchanan
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Jennifer J Waldo
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Samantha R Lock
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | | | - Henriette O’Geen
- Genome Center and Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA
| | - David J Segal
- Genome Center and Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA
| | - Jan Nolta
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
| | - Kyle D Fink
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Stem Cell Program and Gene Therapy Center, University of California, Davis, Sacramento, CA, USA
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22
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Widespread organ tolerance to Xist loss and X reactivation except under chronic stress in the gut. Proc Natl Acad Sci U S A 2020; 117:4262-4272. [PMID: 32041873 DOI: 10.1073/pnas.1917203117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Long thought to be dispensable after establishing X chromosome inactivation (XCI), Xist RNA is now known to also maintain the inactive X (Xi). To what extent somatic X reactivation causes physiological abnormalities is an active area of inquiry. Here, we use multiple mouse models to investigate in vivo consequences. First, when Xist is deleted systemically in post-XCI embryonic cells using the Meox2-Cre driver, female pups exhibit no morbidity or mortality despite partial X reactivation. Second, when Xist is conditionally deleted in epithelial cells using Keratin14-Cre or in B cells using CD19-Cre, female mice have a normal life span without obvious illness. Third, when Xist is deleted in gut using Villin-Cre, female mice remain healthy despite significant X-autosome dosage imbalance. Finally, when the gut is acutely stressed by azoxymethane/dextran sulfate (AOM/DSS) exposure, both Xist-deleted and wild-type mice develop gastrointestinal tumors. Intriguingly, however, under prolonged stress, mutant mice develop larger tumors and have a higher tumor burden. The effect is female specific. Altogether, these observations reveal a surprising systemic tolerance to Xist loss but importantly reveal that Xist and XCI are protective to females during chronic stress.
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23
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Janiszewski A, Talon I, Chappell J, Collombet S, Song J, De Geest N, To SK, Bervoets G, Marin-Bejar O, Provenzano C, Vanheer L, Marine JC, Rambow F, Pasque V. Dynamic reversal of random X-Chromosome inactivation during iPSC reprogramming. Genome Res 2019; 29:1659-1672. [PMID: 31515287 PMCID: PMC6771397 DOI: 10.1101/gr.249706.119] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 08/07/2019] [Indexed: 12/13/2022]
Abstract
Induction and reversal of chromatin silencing is critical for successful development, tissue homeostasis, and the derivation of induced pluripotent stem cells (iPSCs). X-Chromosome inactivation (XCI) and reactivation (XCR) in female cells represent chromosome-wide transitions between active and inactive chromatin states. Although XCI has long been studied, providing important insights into gene regulation, the dynamics and mechanisms underlying the reversal of stable chromatin silencing of X-linked genes are much less understood. Here, we use allele-specific transcriptomics to study XCR during mouse iPSC reprogramming in order to elucidate the timing and mechanisms of chromosome-wide reversal of gene silencing. We show that XCR is hierarchical, with subsets of genes reactivating early, late, and very late during reprogramming. Early genes are activated before the onset of late pluripotency genes activation. Early genes are located genomically closer to genes that escape XCI, unlike genes reactivating late. Early genes also show increased pluripotency transcription factor (TF) binding. We also reveal that histone deacetylases (HDACs) restrict XCR in reprogramming intermediates and that the severe hypoacetylation state of the inactive X Chromosome (Xi) persists until late reprogramming stages. Altogether, these results reveal the timing of transcriptional activation of monoallelically repressed genes during iPSC reprogramming, and suggest that allelic activation involves the combined action of chromatin topology, pluripotency TFs, and chromatin regulators. These findings are important for our understanding of gene silencing, maintenance of cell identity, reprogramming, and disease.
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Affiliation(s)
- Adrian Janiszewski
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Irene Talon
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Joel Chappell
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Samuel Collombet
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Juan Song
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Natalie De Geest
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - San Kit To
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Greet Bervoets
- Laboratory for Molecular Cancer Biology, VIB Center for Cancer Biology, KU Leuven, 3000 Leuven, Belgium.,Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Oskar Marin-Bejar
- Laboratory for Molecular Cancer Biology, VIB Center for Cancer Biology, KU Leuven, 3000 Leuven, Belgium.,Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Caterina Provenzano
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Lotte Vanheer
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
| | - Jean-Christophe Marine
- Laboratory for Molecular Cancer Biology, VIB Center for Cancer Biology, KU Leuven, 3000 Leuven, Belgium.,Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Florian Rambow
- Laboratory for Molecular Cancer Biology, VIB Center for Cancer Biology, KU Leuven, 3000 Leuven, Belgium.,Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Vincent Pasque
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, B-3000 Leuven, Belgium
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24
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Yamamoto-Shimojima K, Imaizumi T, Aoki Y, Inoue K, Kaname T, Okuno Y, Muramatsu H, Kato K, Yamamoto T. Elucidation of the pathogenic mechanism and potential treatment strategy for a female patient with spastic paraplegia derived from a single-nucleotide deletion in PLP1. J Hum Genet 2019; 64:665-671. [PMID: 31004103 DOI: 10.1038/s10038-019-0600-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/24/2019] [Accepted: 04/04/2019] [Indexed: 11/09/2022]
Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder caused by abnormalities in the gene PLP1. Most females harboring heterozygous PLP1 abnormalities are basically asymptomatic. However, as a result of abnormal patterns of X-chromosome inactivation, it is possible for some female carriers to be symptomatic. Whole-exome sequencing of a female patient with unknown spastic paraplegia was performed to obtain a molecular diagnosis. As a result, a de novo heterozygous single-nucleotide deletion in PLP1 [NM_000533.5(PLP1_v001):c.783del; p.Thr262Leufs*20] was identified. RNA sequencing was performed in a patient-derived lymphoblastoid cell line, confirming mono-allelic expression of the mutated allele and abnormal inactivation of the wild-type allele. The patient-derived lymphoblastoid cell line was then treated with VX680 or 5azadC, which resulted in restored expression of the wild-type allele. These two agents thus have the potential to reverse inappropriately-skewed inactivation of the X-chromosome.
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Affiliation(s)
- Keiko Yamamoto-Shimojima
- Japan Society for the Promotion of Science (RPD), Tokyo, 160-8582, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.,Tokyo Women's Medical University, Institute of Integrated Medical Sciences, Tokyo, 162-8666, Japan
| | - Taichi Imaizumi
- Department of Gene Medicine, Graduate school of Medicine, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.,Department of Pediatrics, St. Marianna University School of Medicine, Kawasaki, 216-8511, Japan
| | - Yusuke Aoki
- Department of Neurology, Aichi Children's Health and Medical Center, Aichi, 474-8710, Japan
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, 187-0031, Japan
| | - Tadashi Kaname
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, 157-8535, Japan
| | - Yusuke Okuno
- Center for Advanced Medicine and Clinical Research, Department of Advanced Medicine, Nagoya University Hospital, Nagoya, 466-8560, Japan
| | - Hideki Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8560, Japan
| | - Kohji Kato
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8560, Japan
| | - Toshiyuki Yamamoto
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, 162-8666, Japan. .,Tokyo Women's Medical University, Institute of Integrated Medical Sciences, Tokyo, 162-8666, Japan. .,Department of Gene Medicine, Graduate school of Medicine, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.
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25
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Treating Rett syndrome: from mouse models to human therapies. Mamm Genome 2019; 30:90-110. [PMID: 30820643 PMCID: PMC6606665 DOI: 10.1007/s00335-019-09793-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 02/09/2019] [Indexed: 02/06/2023]
Abstract
Rare diseases are very difficult to study mechanistically and to develop therapies for because of the scarcity of patients. Here, the rare neuro-metabolic disorder Rett syndrome (RTT) is discussed as a prototype for precision medicine, demonstrating how mouse models have led to an understanding of the development of symptoms. RTT is caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). Mecp2-mutant mice are being used in preclinical studies that target the MECP2 gene directly, or its downstream pathways. Importantly, this work may improve the health of RTT patients. Clinical presentation may vary widely among individuals based on their mutation, but also because of the degree of X chromosome inactivation and the presence of modifier genes. Because it is a complex disorder involving many organ systems, it is likely that recovery of RTT patients will involve a combination of treatments. Precision medicine is warranted to provide the best efficacy to individually treat RTT patients.
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26
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Zhang J, Chen Y, Gao M, Wang Z, Liu R, Xia T, Liu S. Silver Nanoparticles Compromise Female Embryonic Stem Cell Differentiation through Disturbing X Chromosome Inactivation. ACS NANO 2019; 13:2050-2061. [PMID: 30650303 DOI: 10.1021/acsnano.8b08604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The widespread use of silver nanoparticles (AgNPs) has raised substantial health risks to human beings. Despite a wealth of progress on toxicity studies, the understanding of the adverse effects on fetuses, embryos, and early stage cells is still rather limited, particularly under low-dose exposure settings. Moreover, nearly all previous studies ascribed AgNP-induced toxic effects to oxidative stress. Differently, we here unearthed a mechanism, namely, interruption of X chromosome inactivation (XCI) in female mouse embryonic stem cells (mESCs). Albeit with no observable cytotoxicity, significant differentiation retardation was found in female mESCs upon low-dose AgNP exposure. Mechanistic investigations uncovered expedited inactivation for the inactive X chromosome (Xi) and attenuated maintenance of the active X chromosome (Xa) state during mESC differentiation upon the challenge of low-dose AgNPs, indicative of disordered XCI. Thereby, a few X-linked genes (which are closely involved in orchestrating ESC differentiation) were found to be repressed, partially attributable to reinforced enrichment of histone modification ( e. g., histone 3 lysine 27 trimethylation, H3K27me3) on their promoter regions, as the result of disordered XCI. In stark contrast to female mESCs, no impairment of differentiation was observed in male mESCs under low-dose AgNP exposure. All considered, our data unearthed that AgNPs at low concentrations compromised the differentiation program of female mESCs through disturbing XCI. Thus, this work would provide a model for the type of studies necessary to advance the understandings on AgNP-induced developmental toxicity.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Yongjiu Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Ming Gao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Zhe Wang
- School of Public Health , Xinxiang Medical University , Xinxiang , Henan Province 453003 , China
| | - Rui Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Tian Xia
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
- Division of NanoMedicine, Department of Medicine , University of California Los Angeles , Los Angeles , California 90095 , United States
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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27
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Jégu T, Blum R, Cochrane JC, Yang L, Wang CY, Gilles ME, Colognori D, Szanto A, Marr SK, Kingston RE, Lee JT. Xist RNA antagonizes the SWI/SNF chromatin remodeler BRG1 on the inactive X chromosome. Nat Struct Mol Biol 2019; 26:96-109. [PMID: 30664740 PMCID: PMC6421574 DOI: 10.1038/s41594-018-0176-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/03/2018] [Indexed: 02/08/2023]
Abstract
The noncoding RNA Xist recruits silencing factors to the inactive X chromosome (Xi) and facilitates re-organization of Xi structure. Here, we examine the mouse epigenomic landscape of Xi and assess how Xist alters chromatin accessibility. Interestingly, Xist deletion triggers a gain of accessibility of selective chromatin regions that is regulated by BRG1, an ATPase subunit of the SWI/SNF chromatin remodeling complex. In vitro, RNA binding inhibits nucleosome remodeling and ATPase activities of BRG1, while in cell culture Xist directly interacts with BRG1 and expels BRG1 from the Xi. Xist ablation leads to a selective return of BRG1 in cis, starting from pre-existing BRG1 sites that are free of Xist. BRG1 re-association correlates with cohesin binding and restoration of topologically associated domains (TADs), and results in formation of de novo Xi “superloops.” Thus, Xist binding inhibits BRG1’s nucleosome remodeling activity and results in expulsion of the SWI/SNF complex from the Xi.
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Affiliation(s)
- Teddy Jégu
- Howard Hughes Medical Institute, Boston, MA, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Roy Blum
- Howard Hughes Medical Institute, Boston, MA, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Jesse C Cochrane
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Lin Yang
- Howard Hughes Medical Institute, Boston, MA, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Chen-Yu Wang
- Howard Hughes Medical Institute, Boston, MA, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Maud-Emmanuelle Gilles
- Institute for RNA Medicine, Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - David Colognori
- Howard Hughes Medical Institute, Boston, MA, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Attila Szanto
- Howard Hughes Medical Institute, Boston, MA, USA.,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Sharon K Marr
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Jeannie T Lee
- Howard Hughes Medical Institute, Boston, MA, USA. .,Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, USA.
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28
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Waśko U, Zheng Z, Bhatnagar S. Visualization of Xist Long Noncoding RNA with a Fluorescent CRISPR/Cas9 System. Methods Mol Biol 2019; 1870:41-50. [PMID: 30539545 DOI: 10.1007/978-1-4939-8808-2_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
X-inactive specific transcript (Xist) is a long noncoding RNA that is essential for initiating and maintaining epigenetic silencing of one copy of the X chromosome in mammalian females. But the mechanism by which Xist localizes and spreads on the X chromosome and facilitates transcriptional silencing remains largely unknown. This limited understanding, at least in part, is due to the technical difficulties in the visualization and functional characterization of Xist. Development of a successful method for Xist tracking is a key to better understanding of the X chromosome silencing, as well as to gain insight into the regulatory role of other long noncoding RNAs. Here, we describe an alternative method for visualization of Xist lncRNA in cells using a CRISPR/Cas9-based approach. This strategy is relatively simple approach to track Xist at different stages of cell differentiation, providing mechanistic insights into the initiation, maintenance, and establishment of X inactivation.
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Affiliation(s)
- Urszula Waśko
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Zeming Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Sanchita Bhatnagar
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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29
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Adrianse RL, Smith K, Gatbonton-Schwager T, Sripathy SP, Lao U, Foss EJ, Boers RG, Boers JB, Gribnau J, Bedalov A. Perturbed maintenance of transcriptional repression on the inactive X-chromosome in the mouse brain after Xist deletion. Epigenetics Chromatin 2018; 11:50. [PMID: 30170615 PMCID: PMC6118007 DOI: 10.1186/s13072-018-0219-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/16/2018] [Indexed: 01/22/2023] Open
Abstract
Background The long noncoding RNA Xist is critical for initiation and establishment of X-chromosome inactivation during embryogenesis in mammals, but it is unclear whether its continued expression is required for maintaining X-inactivation in vivo. Results By using an inactive X-chromosome-linked MeCP2-GFP reporter, which allowed us to enumerate reactivation events in the mouse brain even when they occur in very few cells, we found that deletion of Xist in the brain after establishment of X-chromosome inactivation leads to reactivation in 2–5% of neurons and in a smaller fraction of astrocytes. In contrast to global loss of both H3 lysine 27 trimethylation (H3K27m3) and histone H2A lysine 119 monoubiquitylation (H2AK119ub1) we observed upon Xist deletion, alterations in CpG methylation were subtle, and this was mirrored by only minor alterations in X-chromosome-wide gene expression levels, with highly expressed genes more prone to both derepression and demethylation compared to genes with low expression level. Conclusion Our results demonstrate that Xist plays a role in the maintenance of histone repressive marks, DNA methylation and transcriptional repression on the inactive X-chromosome, but that partial loss of X-dosage compensation in the absence of Xist in the brain is well tolerated. Electronic supplementary material The online version of this article (10.1186/s13072-018-0219-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Robin L Adrianse
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA
| | - Kaleb Smith
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA
| | - Tonibelle Gatbonton-Schwager
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA
| | - Smitha P Sripathy
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA
| | - Uyen Lao
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA
| | - Eric J Foss
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA
| | - Ruben G Boers
- Department of Developmental Biology, Erasmus MC, 3015 CN, Rotterdam, The Netherlands.,Department of Obstetrics and Gynaecology, Erasmus MC, 3015 CN, Rotterdam, The Netherlands
| | - Joachim B Boers
- Department of Developmental Biology, Erasmus MC, 3015 CN, Rotterdam, The Netherlands.,Delft Diagnostic Laboratories, 2288 ER, Rijswijk, The Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus MC, 3015 CN, Rotterdam, The Netherlands
| | - Antonio Bedalov
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., Seattle, WA, 98109, USA. .,Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA. .,Department of Medicine, University of Washington, Seattle, WA, 98195, USA.
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30
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Tsix-Mecp2 female mouse model for Rett syndrome reveals that low-level MECP2 expression extends life and improves neuromotor function. Proc Natl Acad Sci U S A 2018; 115:8185-8190. [PMID: 30038001 DOI: 10.1073/pnas.1800931115] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rett syndrome (RTT) is a severe neurodevelopmental disorder caused by a mutation in the X-linked methyl-CpG-binding protein 2 (MECP2). There is currently no disease-specific treatment, but MECP2 restoration through reactivation of the inactive X (Xi) has been of considerable interest. Progress toward an Xi-reactivation therapy has been hampered by a lack of suitable female mouse models. Because of cellular mosaicism due to random X-chromosome inactivation (XCI), Mecp2+/- heterozygous females develop only mild RTT. Here, we create an improved female mouse model by introducing a mutation in Tsix, the antisense regulator of XCI allelic choice. Tsix-Mecp2 mice show reduced MECP2 mosaicism and closely phenocopy the severely affected Mecp2-null males. Tsix-Mecp2 females demonstrate shortened lifespan, motor weakness, tremors, and gait disturbance. Intriguingly, they also exhibit repetitive behaviors, as is often seen in human RTT, including excessive grooming and biting that result in self-injury. With a Tsix allelic series, we vary MECP2 levels in brain and demonstrate a direct, but nonlinear correlation between MECP2 levels and phenotypic improvement. As little as 5-10% MECP2 restoration improves neuromotor function and extends lifespan five- to eightfold. Our study thus guides future pharmacological strategies and suggests that partial MECP2 restoration could have disproportionate therapeutic benefit.
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31
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Pharmacological reactivation of inactive X-linked Mecp2 in cerebral cortical neurons of living mice. Proc Natl Acad Sci U S A 2018; 115:7991-7996. [PMID: 30012595 DOI: 10.1073/pnas.1803792115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Rett syndrome (RTT) is a genetic disorder resulting from a loss-of-function mutation in one copy of the X-linked gene methyl-CpG-binding protein 2 (MECP2). Typical RTT patients are females and, due to random X chromosome inactivation (XCI), ∼50% of cells express mutant MECP2 and the other ∼50% express wild-type MECP2. Cells expressing mutant MECP2 retain a wild-type copy of MECP2 on the inactive X chromosome (Xi), the reactivation of which represents a potential therapeutic approach for RTT. Previous studies have demonstrated reactivation of Xi-linked MECP2 in cultured cells by biological or pharmacological inhibition of factors that promote XCI (called "XCI factors" or "XCIFs"). Whether XCIF inhibitors in living animals can reactivate Xi-linked MECP2 in cerebral cortical neurons, the cell type most therapeutically relevant to RTT, remains to be determined. Here, we show that pharmacological inhibitors targeting XCIFs in the PI3K/AKT and bone morphogenetic protein signaling pathways reactivate Xi-linked MECP2 in cultured mouse fibroblasts and human induced pluripotent stem cell-derived postmitotic RTT neurons. Notably, reactivation of Xi-linked MECP2 corrects characteristic defects of human RTT neurons including reduced soma size and branch points. Most importantly, we show that intracerebroventricular injection of the XCIF inhibitors reactivates Xi-linked Mecp2 in cerebral cortical neurons of adult living mice. In support of these pharmacological results, we also demonstrate genetic reactivation of Xi-linked Mecp2 in cerebral cortical neurons of living mice bearing a homozygous XCIF deletion. Collectively, our results further establish the feasibility of pharmacological reactivation of Xi-linked MECP2 as a therapeutic approach for RTT.
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32
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Monfort A, Wutz A. Progress in understanding the molecular mechanism of Xist RNA function through genetics. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0368. [PMID: 28947663 DOI: 10.1098/rstb.2016.0368] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2017] [Indexed: 01/06/2023] Open
Abstract
The Xist gene produces a long noncoding RNA that initiates chromosome-wide gene repression on the inactive X chromosome in female mammals. Recent progress has advanced the understanding of Xist function at the molecular level. This review provides an overview of insights from genetic approaches and puts the new data in the context of an emerging mechanistic model as well as the existing literature. Some consideration is given on how independent biochemical studies on X inactivation help to advance on the wider question of chromatin regulation in the mammalian dosage compensation system.This article is part of the themed issue 'X-chromosome inactivation: a tribute to Mary Lyon'.
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Affiliation(s)
- Asun Monfort
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Hönggerberg, Otto-Stern-Weg 7, 8049 Zurich, Switzerland
| | - Anton Wutz
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Hönggerberg, Otto-Stern-Weg 7, 8049 Zurich, Switzerland
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33
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Abstract
Rett Syndrome is a severe neurological disorder mainly due to
de novo mutations in the methyl-CpG-binding protein 2 gene (
MECP2). Mecp2 is known to play a role in chromatin organization and transcriptional regulation. In this review, we report the latest advances on the molecular function of Mecp2 and the new animal and cellular models developed to better study Rett syndrome. Finally, we present the latest innovative therapeutic approaches, ranging from classical pharmacology to correct symptoms to more innovative approaches intended to cure the pathology.
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Affiliation(s)
- Yann Ehinger
- Aix Marseille Univ, INSERM, MMG, 13385 Marseille, France
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34
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Abstract
PURPOSE OF REVIEW Neurodevelopmental disorders disproportionately affect males. The mechanisms underlying male vulnerability or female protection are not known and remain understudied. Determining the processes involved is crucial to understanding the etiology and advancing treatment of neurodevelopmental disorders. Here, we review current findings and theories that contribute to male preponderance of neurodevelopmental disorders, with a focus on autism. RECENT FINDINGS Recent work on the biological basis of the male preponderance of autism and other neurodevelopmental disorders includes discussion of a higher genetic burden in females and sex-specific gene mutations or epigenetic changes that differentially confer risk to males or protection to females. Other mechanisms discussed are sex chromosome and sex hormone involvement. Specifically, fetal testosterone is involved in many aspects of development and may interact with neurotransmitter, neuropeptide, or immune pathways to contribute to male vulnerability. Finally, the possibilities of female underdiagnosis and a multi-hit hypothesis are discussed. This review highlights current theories of male bias in developmental disorders. Topics include environmental, genetic, and epigenetic mechanisms; theories of sex chromosomes, hormones, neuroendocrine, and immune function; underdiagnosis of females; and a multi-hit hypothesis.
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Affiliation(s)
- Sarah L. Ferri
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, IA 52242 USA
| | - Ted Abel
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, IA 52242 USA
| | - Edward S. Brodkin
- Center for Neurobiology and Behavior, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Translational Research Laboratory, 125 South 31 Street, Room 2202, Philadelphia, PA 19104-3403 USA
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35
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Leko V, Sripathy S, Adrianse RL, Loe T, Park A, Lao U, Foss EJ, Bartolomei MS, Bedalov A. Pooled shRNA Screen for Reactivation of MeCP2 on the Inactive X Chromosome. J Vis Exp 2018. [PMID: 29553562 DOI: 10.3791/56398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Forward genetic screens using reporter genes inserted into the heterochromatin have been extensively used to investigate mechanisms of epigenetic control in model organisms. Technologies including short hairpin RNAs (shRNAs) and clustered regularly interspaced short palindromic repeats (CRISPR) have enabled such screens in diploid mammalian cells. Here we describe a large-scale shRNA screen for regulators of X-chromosome inactivation (XCI), using a murine cell line with firefly luciferase and hygromycin resistance genes knocked in at the C-terminus of the methyl CpG binding protein 2 (MeCP2) gene on the inactive X-chromosome (Xi). Reactivation of the construct in the reporter cell line conferred survival advantage under hygromycin B selection, enabling us to screen a large shRNA library and identify hairpins that reactivated the reporter by measuring their post-selection enrichment using next-generation sequencing. The enriched hairpins were then individually validated by testing their ability to activate the luciferase reporter on Xi.
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Affiliation(s)
- Vid Leko
- Clinical Research Division, Fred Hutchinson Cancer Research Center; Hematology Branch, National Heart, Lung and Blood Institute, National Institutes of Health
| | - Smitha Sripathy
- Clinical Research Division, Fred Hutchinson Cancer Research Center
| | - Robin L Adrianse
- Clinical Research Division, Fred Hutchinson Cancer Research Center
| | - Taylor Loe
- Clinical Research Division, Fred Hutchinson Cancer Research Center
| | - Angela Park
- Clinical Research Division, Fred Hutchinson Cancer Research Center
| | - Uyen Lao
- Clinical Research Division, Fred Hutchinson Cancer Research Center
| | - Eric J Foss
- Clinical Research Division, Fred Hutchinson Cancer Research Center
| | - Marisa S Bartolomei
- Epigenetics Program, Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine
| | - Antonio Bedalov
- Clinical Research Division, Fred Hutchinson Cancer Research Center; Departments of Medicine and Biochemistry, University of Washington;
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36
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A mixed modality approach towards Xi reactivation for Rett syndrome and other X-linked disorders. Proc Natl Acad Sci U S A 2017; 115:E668-E675. [PMID: 29282321 DOI: 10.1073/pnas.1715124115] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The X-chromosome harbors hundreds of disease genes whose associated diseases predominantly affect males. However, a subset, including neurodevelopmental disorders, Rett syndrome (RTT), fragile X syndrome, and CDKL5 syndrome, also affects females. These disorders lack disease-specific treatment. Because female cells carry two X chromosomes, an emerging treatment strategy has been to reawaken the healthy allele on the inactive X (Xi). Here, we focus on methyl-CpG binding protein 2 (MECP2) restoration for RTT and combinatorially target factors in the interactome of Xist, the noncoding RNA responsible for X inactivation. We identify a mixed modality approach combining an Xist antisense oligonucleotide and a small-molecule inhibitor of DNA methylation, which, together, achieve 30,000-fold MECP2 up-regulation from the Xi in cultured cells. Combining a brain-specific genetic Xist ablation with short-term 5-aza-2'-deoxycytidine (Aza) treatment models the synergy in vivo without evident toxicity. The Xi is selectively reactivated. These experiments provide proof of concept for a mixed modality approach for treating X-linked disorders in females.
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37
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Jin XR, Chen XS, Xiao L. MeCP2 Deficiency in Neuroglia: New Progress in the Pathogenesis of Rett Syndrome. Front Mol Neurosci 2017; 10:316. [PMID: 29046627 PMCID: PMC5632713 DOI: 10.3389/fnmol.2017.00316] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 09/19/2017] [Indexed: 01/24/2023] Open
Abstract
Rett syndrome (RTT) is an X-linked neurodevelopmental disease predominantly caused by mutations of the methyl-CpG-binding protein 2 (MeCP2) gene. Generally, RTT has been attributed to neuron-centric dysfunction. However, increasing evidence has shown that glial abnormalities are also involved in the pathogenesis of RTT. Mice that are MeCP2-null specifically in glial cells showed similar behavioral and/or neuronal abnormalities as those found in MeCP2-null mice, a mouse model of RTT. MeCP2 deficiency in astrocytes impacts the expression of glial intermediate filament proteins such as fibrillary acidic protein (GFAP) and S100 and induces neuron toxicity by disturbing glutamate metabolism or enhancing microtubule instability. MeCP2 deficiency in oligodendrocytes (OLs) results in down-regulation of myelin gene expression and impacts myelination. While MeCP2-deficient microglia cells fail in response to environmental stimuli, release excessive glutamate, and aggravate impairment of the neuronal circuit. In this review, we mainly focus on the progress in determining the role of MeCP2 in glial cells involved in RTT, which may provide further insight into a therapeutic intervention for RTT.
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Affiliation(s)
- Xu-Rui Jin
- Department of Histology and Embryology, Faculty of Basic Medicine, Collaborative Program for Brain Research, Third Military Medical University, Chongqing, China.,The Cadet Brigade of Clinic Medicine, Third Military Medical University, Chongqing, China
| | - Xing-Shu Chen
- Department of Histology and Embryology, Faculty of Basic Medicine, Collaborative Program for Brain Research, Third Military Medical University, Chongqing, China
| | - Lan Xiao
- Department of Histology and Embryology, Faculty of Basic Medicine, Collaborative Program for Brain Research, Third Military Medical University, Chongqing, China
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38
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Robert Finestra T, Gribnau J. X chromosome inactivation: silencing, topology and reactivation. Curr Opin Cell Biol 2017; 46:54-61. [PMID: 28236732 DOI: 10.1016/j.ceb.2017.01.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/19/2017] [Accepted: 01/30/2017] [Indexed: 01/22/2023]
Abstract
To ensure X-linked gene dosage compensation between females (XX) and males (XY), one X chromosome undergoes X chromosome inactivation (XCI) in female cells. This process is tightly regulated throughout development by many different factors, with Xist as a key regulator, encoding a long non-coding RNA, involved in establishment of several layers of repressive epigenetic modifications. Several recent studies on XCI focusing on identification and characterization of Xist RNA-protein interactors, revealed new factors involved in gene silencing, genome topology and nuclear membrane attachment, amongst others. Also, new insights in higher order chromatin organization have been presented, revealing differences between the topological organization of active and inactive X chromosomes (Xa and Xi), with associated differences in gene expression. Finally, further evidence indicates that the inactive state of the Xi can be (partially) reversed, and that this X chromosome reactivation (XCR) might be associated with disease.
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Affiliation(s)
- Teresa Robert Finestra
- Department of Developmental Biology, Erasmus MC, Wytemaweg 80, Rotterdam CN 3015, The Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus MC, Wytemaweg 80, Rotterdam CN 3015, The Netherlands.
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Screen for reactivation of MeCP2 on the inactive X chromosome identifies the BMP/TGF-β superfamily as a regulator of XIST expression. Proc Natl Acad Sci U S A 2017; 114:1619-1624. [PMID: 28143937 DOI: 10.1073/pnas.1621356114] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Rett syndrome (RS) is a debilitating neurological disorder affecting mostly girls with heterozygous mutations in the gene encoding the methyl-CpG-binding protein MeCP2 on the X chromosome. Because restoration of MeCP2 expression in a mouse model reverses neurologic deficits in adult animals, reactivation of the wild-type copy of MeCP2 on the inactive X chromosome (Xi) presents a therapeutic opportunity in RS. To identify genes involved in MeCP2 silencing, we screened a library of 60,000 shRNAs using a cell line with a MeCP2 reporter on the Xi and found 30 genes clustered in seven functional groups. More than half encoded proteins with known enzymatic activity, and six were members of the bone morphogenetic protein (BMP)/TGF-β pathway. shRNAs directed against each of these six genes down-regulated X-inactive specific transcript (XIST), a key player in X-chromosome inactivation that encodes an RNA that coats the silent X chromosome, and modulation of regulators of this pathway both in cell culture and in mice demonstrated robust regulation of XIST. Moreover, we show that Rnf12, an X-encoded ubiquitin ligase important for initiation of X-chromosome inactivation and XIST transcription in ES cells, also plays a role in maintenance of the inactive state through regulation of BMP/TGF-β signaling. Our results identify pharmacologically suitable targets for reactivation of MeCP2 on the Xi and a genetic circuitry that maintains XIST expression and X-chromosome inactivation in differentiated cells.
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Yang T, Yildirim E. Epigenetic and LncRNA-Mediated Regulation of X Chromosome Inactivation and Its Impact on Pathogenesis. CURRENT PATHOBIOLOGY REPORTS 2017. [DOI: 10.1007/s40139-017-0120-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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The Role of Noncoding RNAs in Neurodevelopmental Disorders: The Case of Rett Syndrome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 978:23-37. [DOI: 10.1007/978-3-319-53889-1_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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42
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Lessing D, Dial TO, Wei C, Payer B, Carrette LLG, Kesner B, Szanto A, Jadhav A, Maloney DJ, Simeonov A, Theriault J, Hasaka T, Bedalov A, Bartolomei MS, Lee JT. A high-throughput small molecule screen identifies synergism between DNA methylation and Aurora kinase pathways for X reactivation. Proc Natl Acad Sci U S A 2016; 113:14366-14371. [PMID: 28182563 PMCID: PMC5167172 DOI: 10.1073/pnas.1617597113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
X-chromosome inactivation is a mechanism of dosage compensation in which one of the two X chromosomes in female mammals is transcriptionally silenced. Once established, silencing of the inactive X (Xi) is robust and difficult to reverse pharmacologically. However, the Xi is a reservoir of >1,000 functional genes that could be potentially tapped to treat X-linked disease. To identify compounds that could reactivate the Xi, here we screened ∼367,000 small molecules in an automated high-content screen using an Xi-linked GFP reporter in mouse fibroblasts. Given the robust nature of silencing, we sensitized the screen by "priming" cells with the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5azadC). Compounds that elicited GFP activity include VX680, MLN8237, and 5azadC, which are known to target the Aurora kinase and DNA methylation pathways. We demonstrate that the combinations of VX680 and 5azadC, as well as MLN8237 and 5azadC, synergistically up-regulate genes on the Xi. Thus, our work identifies a synergism between the DNA methylation and Aurora kinase pathways as being one of interest for possible pharmacological reactivation of the Xi.
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Affiliation(s)
- Derek Lessing
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Thomas O Dial
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Chunyao Wei
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | | | - Lieselot L G Carrette
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
- Center for Medical Genetics, Ghent University, 9000 Ghent, Belgium
| | - Barry Kesner
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Attila Szanto
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Ajit Jadhav
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - David J Maloney
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | - Anton Simeonov
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850
| | | | | | - Antonio Bedalov
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Marisa S Bartolomei
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Jeannie T Lee
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114;
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114
- Department of Genetics, Harvard Medical School, Boston, MA 02115
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43
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Leonard H, Cobb S, Downs J. Clinical and biological progress over 50 years in Rett syndrome. Nat Rev Neurol 2016; 13:37-51. [PMID: 27934853 DOI: 10.1038/nrneurol.2016.186] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families.
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Affiliation(s)
- Helen Leonard
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Jenny Downs
- Telethon Kids Institute, 100 Roberts Road, Subiaco, Perth, Western Australia 6008, Australia
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CLIP-GENE: a web service of the condition specific context-laid integrative analysis for gene prioritization in mouse TF knockout experiments. Biol Direct 2016; 11:57. [PMID: 27776539 PMCID: PMC5078909 DOI: 10.1186/s13062-016-0158-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/10/2016] [Indexed: 02/06/2023] Open
Abstract
MOTIVATION Transcriptome data from the gene knockout experiment in mouse is widely used to investigate functions of genes and relationship to phenotypes. When a gene is knocked out, it is important to identify which genes are affected by the knockout gene. Existing methods, including differentially expressed gene (DEG) methods, can be used for the analysis. However, existing methods require cutoff values to select candidate genes, which can produce either too many false positives or false negatives. This hurdle can be addressed either by improving the accuracy of gene selection or by providing a method to rank candidate genes effectively, or both. Prioritization of candidate genes should consider the goals or context of the knockout experiment. As of now, there are no tools designed for both selecting and prioritizing genes from the mouse knockout data. Hence, the necessity of a new tool arises. RESULTS In this study, we present CLIP-GENE, a web service that selects gene markers by utilizing differentially expressed genes, mouse transcription factor (TF) network, and single nucleotide variant information. Then, protein-protein interaction network and literature information are utilized to find genes that are relevant to the phenotypic differences. One of the novel features is to allow researchers to specify their contexts or hypotheses in a set of keywords to rank genes according to the contexts that the user specify. We believe that CLIP-GENE will be useful in characterizing functions of TFs in mouse experiments. AVAILABILITY http://epigenomics.snu.ac.kr/CLIP-GENE REVIEWERS: This article was reviewed by Dr. Lee and Dr. Pongor.
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Kaufmann WE, Stallworth JL, Everman DB, Skinner SA. Neurobiologically-based treatments in Rett syndrome: opportunities and challenges. Expert Opin Orphan Drugs 2016; 4:1043-1055. [PMID: 28163986 PMCID: PMC5214376 DOI: 10.1080/21678707.2016.1229181] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/23/2016] [Indexed: 12/14/2022]
Abstract
Introduction: Rett syndrome (RTT) is an X-linked neurodevelopmental disorder that primarily affects females, typically resulting in a period of developmental regression in early childhood followed by stabilization and severe chronic cognitive, behavioral, and physical disability. No known treatment exists beyond symptomatic management, and while insights into the genetic cause, pathophysiology, neurobiology, and natural history of RTT have been gained, many challenges remain. Areas covered: Based on a comprehensive survey of the primary literature on RTT, this article describes and comments upon the general and unique features of the disorder, genetic and neurobiological bases of drug development, and the history of clinical trials in RTT, with an emphasis on drug trial design, outcome measures, and implementation. Expert opinion: Neurobiologically based drug trials are the ultimate goal in RTT, and due to the complexity and global nature of the disorder, drugs targeting both general mechanisms (e.g., growth factors) and specific systems (e.g., glutamate modulators) could be effective. Trial design should optimize data on safety and efficacy, but selection of outcome measures with adequate measurement properties, as well as innovative strategies, such as those enhancing synaptic plasticity and use of biomarkers, are essential for progress in RTT and other neurodevelopmental disorders.
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Affiliation(s)
- Walter E Kaufmann
- Center for Translational Research, Greenwood Genetic Center, Greenwood, SC, USA; Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | | | - David B Everman
- Center for Translational Research, Greenwood Genetic Center , Greenwood , SC , USA
| | - Steven A Skinner
- Center for Translational Research, Greenwood Genetic Center , Greenwood , SC , USA
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46
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Furlan G, Rougeulle C. Function and evolution of the long noncoding RNA circuitry orchestrating X-chromosome inactivation in mammals. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:702-22. [PMID: 27173581 DOI: 10.1002/wrna.1359] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 12/20/2022]
Abstract
X-chromosome inactivation (XCI) is a chromosome-wide regulatory process that ensures dosage compensation for X-linked genes in Theria. XCI is established during early embryogenesis and is developmentally regulated. Different XCI strategies exist in mammalian infraclasses and the regulation of this process varies also among closely related species. In Eutheria, initiation of XCI is orchestrated by a cis-acting locus, the X-inactivation center (Xic), which is particularly enriched in genes producing long noncoding RNAs (lncRNAs). Among these, Xist generates a master transcript that coats and propagates along the future inactive X-chromosome in cis, establishing X-chromosome wide transcriptional repression through interaction with several protein partners. Other lncRNAs also participate to the regulation of X-inactivation but the extent to which their function has been maintained in evolution is still poorly understood. In Metatheria, Xist is not conserved, but another, evolutionary independent lncRNA with similar properties, Rsx, has been identified, suggesting that lncRNA-mediated XCI represents an evolutionary advantage. Here, we review current knowledge on the interplay of X chromosome-encoded lncRNAs in ensuring proper establishment and maintenance of chromosome-wide silencing, and discuss the evolutionary implications of the emergence of species-specific lncRNAs in the control of XCI within Theria. WIREs RNA 2016, 7:702-722. doi: 10.1002/wrna.1359 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Giulia Furlan
- Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR7216 CNRS, Université Paris Diderot, Paris, France
| | - Claire Rougeulle
- Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR7216 CNRS, Université Paris Diderot, Paris, France
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47
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Impairments in dendrite morphogenesis as etiology for neurodevelopmental disorders and implications for therapeutic treatments. Neurosci Biobehav Rev 2016; 68:946-978. [PMID: 27143622 DOI: 10.1016/j.neubiorev.2016.04.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 04/13/2016] [Accepted: 04/13/2016] [Indexed: 02/08/2023]
Abstract
Dendrite morphology is pivotal for neural circuitry functioning. While the causative relationship between small-scale dendrite morphological abnormalities (shape, density of dendritic spines) and neurodevelopmental disorders is well established, such relationship remains elusive for larger-scale dendrite morphological impairments (size, shape, branching pattern of dendritic trees). Here, we summarize published data on dendrite morphological irregularities in human patients and animal models for neurodevelopmental disorders, with focus on autism and schizophrenia. We next discuss high-risk genes for these disorders and their role in dendrite morphogenesis. We finally overview recent developments in therapeutic attempts and we discuss how they relate to dendrite morphology. We find that both autism and schizophrenia are accompanied by dendritic arbor morphological irregularities, and that majority of their high-risk genes regulate dendrite morphogenesis. Thus, we present a compelling argument that, along with smaller-scale morphological impairments in dendrites (spines and synapse), irregularities in larger-scale dendrite morphology (arbor shape, size) may be an important part of neurodevelopmental disorders' etiology. We suggest that this should not be ignored when developing future therapeutic treatments.
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48
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Payer B. Developmental regulation of X-chromosome inactivation. Semin Cell Dev Biol 2016; 56:88-99. [PMID: 27112543 DOI: 10.1016/j.semcdb.2016.04.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/13/2016] [Accepted: 04/21/2016] [Indexed: 12/01/2022]
Abstract
With the emergence of sex-determination by sex chromosomes, which differ in composition and number between males and females, appeared the need to equalize X-chromosomal gene dosage between the sexes. Mammals have devised the strategy of X-chromosome inactivation (XCI), in which one of the two X-chromosomes is rendered transcriptionally silent in females. In the mouse, the best-studied model organism with respect to XCI, this inactivation process occurs in different forms, imprinted and random, interspersed by periods of X-chromosome reactivation (XCR), which is needed to switch between the different modes of XCI. In this review, I describe the recent advances with respect to the developmental control of XCI and XCR and in particular their link to differentiation and pluripotency. Furthermore, I review the mechanisms, which influence the timing and choice, with which one of the two X-chromosomes is chosen for inactivation during random XCI. This has an impact on how females are mosaics with regard to which X-chromosome is active in different cells, which has implications on the severity of diseases caused by X-linked mutations.
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Affiliation(s)
- Bernhard Payer
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology and Universitat Pompeu Fabra (UPF), Dr. Aiguader, 88, Barcelona 08003, Spain.
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49
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Vacca M, Della Ragione F, Scalabrì F, D'Esposito M. X inactivation and reactivation in X-linked diseases. Semin Cell Dev Biol 2016; 56:78-87. [PMID: 26994527 DOI: 10.1016/j.semcdb.2016.03.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/22/2022]
Abstract
X chromosome inactivation (XCI) is the phenomenon by which mammals compensate for dosage of X-linked genes in females (XX) versus males (XY). XCI patterns can be random or show extreme skewing, and can modify the mode of inheritance of X-driven phenotypes, which contributes to the variability of human pathologies. Recent findings have shown reversibility of the XCI process, which has opened new avenues in the approaches used for the treatment of X-linked diseases.
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Affiliation(s)
- Marcella Vacca
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy.
| | - Floriana Della Ragione
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy; IRCCS Neuromed, Pozzilli, Isernia, Italy
| | | | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy; IRCCS Neuromed, Pozzilli, Isernia, Italy
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50
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Katz DM, Bird A, Coenraads M, Gray SJ, Menon DU, Philpot BD, Tarquinio DC. Rett Syndrome: Crossing the Threshold to Clinical Translation. Trends Neurosci 2016; 39:100-113. [PMID: 26830113 PMCID: PMC4924590 DOI: 10.1016/j.tins.2015.12.008] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Lying at the intersection between neurobiology and epigenetics, Rett syndrome (RTT) has garnered intense interest in recent years, not only from a broad range of academic scientists, but also from the pharmaceutical and biotechnology industries. In addition to the critical need for treatments for this devastating disorder, optimism for developing RTT treatments derives from a unique convergence of factors, including a known monogenic cause, reversibility of symptoms in preclinical models, a strong clinical research infrastructure highlighted by an NIH-funded natural history study and well-established clinics with significant patient populations. Here, we review recent advances in understanding the biology of RTT, particularly promising preclinical findings, lessons from past clinical trials, and critical elements of trial design for rare disorders.
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Affiliation(s)
- David M Katz
- Departments of Neurosciences and Psychiatry, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Monica Coenraads
- Rett Syndrome Research Trust, 67 Under Cliff Road, Trumbull, CT 06611, USA
| | - Steven J Gray
- Gene Therapy Center and Department of Ophthalmology, University of North Carolina, Chapel Hill, NC USA
| | - Debashish U Menon
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Benjamin D Philpot
- Department of Cell Biology and Physiology, Neuroscience Center, and Carolina Institute for Developmental Disabilities, UNC School of Medicine, Chapel Hill, NC 27599, USA
| | - Daniel C Tarquinio
- Children's Healthcare of Atlanta, Emory University, 1605 Chantilly Drive NE, Atlanta, GA 30324, USA
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