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Khoodoruth MAS, Chut-kai Khoodoruth WN, Al Alwani R. Exploring the epigenetic landscape: The role of 5-hydroxymethylcytosine in neurodevelopmental disorders. CAMBRIDGE PRISMS. PRECISION MEDICINE 2024; 2:e5. [PMID: 38699519 PMCID: PMC11062787 DOI: 10.1017/pcm.2024.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/18/2024] [Accepted: 03/16/2024] [Indexed: 05/05/2024]
Abstract
Recent advances in genetic and epigenetic research have underscored the significance of 5-hydroxymethylcytosine (5hmC) in neurodevelopmental disorders (NDDs), such as autism spectrum disorder (ASD) and intellectual disability (ID), revealing its potential as both a biomarker for early detection and a target for novel therapeutic strategies. This review article provides a comprehensive analysis of the role of 5hmC in NDDs by examining both animal models and human studies. By examining mouse models, studies have demonstrated that prenatal environmental challenges, such as maternal infection and food allergies, lead to significant epigenetic alterations in 5hmC levels, which were associated with NDDs in offspring, impacting social behavior, cognitive abilities and increasing ASD-like symptoms. In human studies, researchers have linked alterations in 5hmC levels NDDs through studies in individuals with ASD, fragile X syndrome, TET3 deficiency and ID, specifically identifying significant epigenetic modifications in genes such as GAD1, RELN, FMR1 and EN-2, suggesting that dysregulation of 5hmC played a critical role in the pathogenesis of these disorders and highlighted the potential for targeted therapeutic interventions. Moreover, we explore the implications of these findings for the development of epigenetic therapies aimed at modulating 5hmC levels. The review concludes with a discussion on future directions for research in this field, such as machine learning, emphasizing the need for further studies to elucidate the complex mechanisms underlying NDDs and to translate these findings into clinical practice. This paper not only advances our understanding of the epigenetic landscape of NDDs but also opens up new avenues for diagnosis and treatment, offering hope for individuals affected by these conditions.
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Affiliation(s)
- Mohamed Adil Shah Khoodoruth
- Department of Child and Adolescent Psychiatry, Hamad Medical Corporation, Doha, Qatar
- Division of Genomics and Precision Medicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | | | - Rafaa Al Alwani
- College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar
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2
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Shah S, Sharp KJ, Raju Ponny S, Lee J, Watts JK, Berry-Kravis E, Richter JD. Antisense oligonucleotide rescue of CGG expansion-dependent FMR1 mis-splicing in fragile X syndrome restores FMRP. Proc Natl Acad Sci U S A 2023; 120:e2302534120. [PMID: 37364131 PMCID: PMC10319035 DOI: 10.1073/pnas.2302534120] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
Aberrant alternative splicing of mRNAs results in dysregulated gene expression in multiple neurological disorders. Here, we show that hundreds of mRNAs are incorrectly expressed and spliced in white blood cells and brain tissues of individuals with fragile X syndrome (FXS). Surprisingly, the FMR1 (Fragile X Messenger Ribonucleoprotein 1) gene is transcribed in >70% of the FXS tissues. In all FMR1-expressing FXS tissues, FMR1 RNA itself is mis-spliced in a CGG expansion-dependent manner to generate the little-known FMR1-217 RNA isoform, which is comprised of FMR1 exon 1 and a pseudo-exon in intron 1. FMR1-217 is also expressed in FXS premutation carrier-derived skin fibroblasts and brain tissues. We show that in cells aberrantly expressing mis-spliced FMR1, antisense oligonucleotide (ASO) treatment reduces FMR1-217, rescues full-length FMR1 RNA, and restores FMRP (Fragile X Messenger RibonucleoProtein) to normal levels. Notably, FMR1 gene reactivation in transcriptionally silent FXS cells using 5-aza-2'-deoxycytidine (5-AzadC), which prevents DNA methylation, increases FMR1-217 RNA levels but not FMRP. ASO treatment of cells prior to 5-AzadC application rescues full-length FMR1 expression and restores FMRP. These findings indicate that misregulated RNA-processing events in blood could serve as potent biomarkers for FXS and that in those individuals expressing FMR1-217, ASO treatment may offer a therapeutic approach to mitigate the disorder.
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Affiliation(s)
- Sneha Shah
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA01605
| | - Kevin J. Sharp
- Department of Pediatrics, Rush University Medical Center, Chicago, IL60612
| | - Sithara Raju Ponny
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA01605
| | - Jonathan Lee
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA01605
| | - Jonathan K. Watts
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA01605
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA01605
- Li Weibo Rare Disease Institute, University of Massachusetts Chan Medical School, Worcester, MA01605
| | - Elizabeth Berry-Kravis
- Department of Pediatrics, Rush University Medical Center, Chicago, IL60612
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL60612
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL60612
| | - Joel D. Richter
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA01605
- Li Weibo Rare Disease Institute, University of Massachusetts Chan Medical School, Worcester, MA01605
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3
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Dias CM, Issac B, Sun L, Lukowicz A, Talukdar M, Akula SK, Miller MB, Walsh K, Rockowitz S, Walsh CA. Glial dysregulation in the human brain in fragile X-associated tremor/ataxia syndrome. Proc Natl Acad Sci U S A 2023; 120:e2300052120. [PMID: 37252957 PMCID: PMC10265985 DOI: 10.1073/pnas.2300052120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/03/2023] [Indexed: 06/01/2023] Open
Abstract
Short trinucleotide expansions at the FMR1 locus are associated with the late-onset condition fragile X-associated tremor/ataxia syndrome (FXTAS), which shows very different clinical and pathological features from fragile X syndrome (associated with longer expansions), with no clear molecular explanation for these marked differences. One prevailing theory posits that the shorter, premutation expansion uniquely causes extreme neurotoxic increases in FMR1 mRNA (i.e., four to eightfold increases), but evidence to support this hypothesis is largely derived from analysis of peripheral blood. We applied single-nucleus RNA sequencing to postmortem frontal cortex and cerebellum from 7 individuals with premutation and matched controls (n = 6) to assess cell type-specific molecular neuropathology. We found only modest upregulation (~1.3-fold) of FMR1 in some glial populations associated with premutation expansions. In premutation cases, we also identified decreased astrocyte proportions in the cortex. Differential expression and gene ontology analysis demonstrated altered neuroregulatory roles of glia. Using network analyses, we identified cell type-specific and region-specific patterns of FMR1 protein target gene dysregulation unique to premutation cases, with notable network dysregulation in the cortical oligodendrocyte lineage. We used pseudotime trajectory analysis to determine how oligodendrocyte development was altered and identified differences in early gene expression in oligodendrocyte trajectories in premutation cases specifically, implicating early cortical glial developmental perturbations. These findings challenge dogma regarding extremely elevated FMR1 increases in FXTAS and implicate glial dysregulation as a critical facet of premutation pathophysiology, representing potential unique therapeutic targets directly derived from the human condition.
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Affiliation(s)
- Caroline M. Dias
- Division of Developmental Medicine, Boston Children’s Hospital, Boston, MA02115
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Department of Pediatrics, Harvard Medical School, Boston, MA02115
- Department of Pediatrics, Section of Developmental Pediatrics, Section of Genetics and Metabolism, and Denver Fragile X Clinic and Research Center, Children’s Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Biju Issac
- Research Computing, Department of Information Technology, Boston Children’s Hospital, Boston, MA02115
| | - Liang Sun
- Research Computing, Department of Information Technology, Boston Children’s Hospital, Boston, MA02115
| | - Abigail Lukowicz
- Department of Pediatrics, Section of Developmental Pediatrics, Section of Genetics and Metabolism, and Denver Fragile X Clinic and Research Center, Children’s Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Maya Talukdar
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Harvard-Massachusetts Institute of Technology MD/PhD Program, Program in Bioinformatics & Integrative Genomics, Harvard Medical School, Boston, MA02115
| | - Shyam K. Akula
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Harvard-Massachusetts Institute of Technology MD/PhD Program, Program in Neuroscience, Harvard Medical School, Boston, MA02115
| | - Michael B. Miller
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
| | - Katherine Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
| | - Shira Rockowitz
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Research Computing, Department of Information Technology, Boston Children’s Hospital, Boston, MA02115
| | - Christopher A. Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA02115
- Department of Pediatrics, Harvard Medical School, Boston, MA02115
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Department of Neurology, Harvard Medical School, Boston, MA02115
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Lee A, Xu J, Wen Z, Jin P. Across Dimensions: Developing 2D and 3D Human iPSC-Based Models of Fragile X Syndrome. Cells 2022; 11:1725. [PMID: 35681419 PMCID: PMC9179297 DOI: 10.3390/cells11111725] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 02/01/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism spectrum disorder. FXS is caused by a cytosine-guanine-guanine (CGG) trinucleotide repeat expansion in the untranslated region of the FMR1 gene leading to the functional loss of the gene's protein product FMRP. Various animal models of FXS have provided substantial knowledge about the disorder. However, critical limitations exist in replicating the pathophysiological mechanisms. Human induced pluripotent stem cells (hiPSCs) provide a unique means of studying the features and processes of both normal and abnormal human neurodevelopment in large sample quantities in a controlled setting. Human iPSC-based models of FXS have offered a better understanding of FXS pathophysiology specific to humans. This review summarizes studies that have used hiPSC-based two-dimensional cellular models of FXS to reproduce the pathology, examine altered gene expression and translation, determine the functions and targets of FMRP, characterize the neurodevelopmental phenotypes and electrophysiological features, and, finally, to reactivate FMR1. We also provide an overview of the most recent studies using three-dimensional human brain organoids of FXS and end with a discussion of current limitations and future directions for FXS research using hiPSCs.
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Affiliation(s)
- Azalea Lee
- Neuroscience Graduate Program, Emory University, Atlanta, GA 30322, USA;
- MD/PhD Program, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jie Xu
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA 30322, USA;
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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5
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Barbé L, Finkbeiner S. Genetic and Epigenetic Interplay Define Disease Onset and Severity in Repeat Diseases. Front Aging Neurosci 2022; 14:750629. [PMID: 35592702 PMCID: PMC9110800 DOI: 10.3389/fnagi.2022.750629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Repeat diseases, such as fragile X syndrome, myotonic dystrophy, Friedreich ataxia, Huntington disease, spinocerebellar ataxias, and some forms of amyotrophic lateral sclerosis, are caused by repetitive DNA sequences that are expanded in affected individuals. The age at which an individual begins to experience symptoms, and the severity of disease, are partially determined by the size of the repeat. However, the epigenetic state of the area in and around the repeat also plays an important role in determining the age of disease onset and the rate of disease progression. Many repeat diseases share a common epigenetic pattern of increased methylation at CpG islands near the repeat region. CpG islands are CG-rich sequences that are tightly regulated by methylation and are often found at gene enhancer or insulator elements in the genome. Methylation of CpG islands can inhibit binding of the transcriptional regulator CTCF, resulting in a closed chromatin state and gene down regulation. The downregulation of these genes leads to some disease-specific symptoms. Additionally, a genetic and epigenetic interplay is suggested by an effect of methylation on repeat instability, a hallmark of large repeat expansions that leads to increasing disease severity in successive generations. In this review, we will discuss the common epigenetic patterns shared across repeat diseases, how the genetics and epigenetics interact, and how this could be involved in disease manifestation. We also discuss the currently available stem cell and mouse models, which frequently do not recapitulate epigenetic patterns observed in human disease, and propose alternative strategies to study the role of epigenetics in repeat diseases.
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Affiliation(s)
- Lise Barbé
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
| | - Steve Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
- *Correspondence: Steve Finkbeiner,
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6
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Xi H, Xie W, Chen J, Tang W, Deng X, Li H, Peng Y, Wang D, Yang S, Zhang Y, Duan R, Fang J, Wang H. Implementation of fragile X syndrome carrier screening during prenatal diagnosis: A pilot study at a single center. Mol Genet Genomic Med 2021; 9:e1711. [PMID: 34057320 PMCID: PMC8372084 DOI: 10.1002/mgg3.1711] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/15/2021] [Accepted: 04/30/2021] [Indexed: 12/02/2022] Open
Abstract
Background Fragile X syndrome (FXS) is the most common inherited form of intellectual disability. Prenatal screening of FXS allows for early identification and intervention. The present study explored the feasibility of FXS carrier screening during prenatal diagnosis for those who were not offered screening early in pregnancy or prior to conception. Methods Pregnant women to be offered amniotic fluid testing were recruited for the free voluntary carrier screening at a single center between August, 2017 and September, 2019. The number of CGG repeats in the 5’ un‐translated region of the fragile X mental retardation gene 1 (FMR1) was determined. Results 4286 of 7000 (61.2%) pregnant women volunteered for the screening. Forty (0.93%), five (0.11%), and three (0.07%) carriers for intermediate mutation (45–54 repeats), premutation (55–200 repeats) and full mutation (>200 repeats) of the FMR1 gene were identified respectively. None of the detected premutation alleles were inherited by the fetuses. Of the three full mutation carrier mothers, all had a family history and one transmitted a full mutation allele to her male fetus. Conclusion Implementation of FXS carrier screening during prenatal diagnosis may be considered for the need to increase screening for FXS.
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Affiliation(s)
- Hui Xi
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China.,NHC Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Wanqin Xie
- NHC Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Jing Chen
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Wanglan Tang
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Xiuli Deng
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Hua Li
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Ying Peng
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China.,NHC Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Dan Wang
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Shuting Yang
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Yanan Zhang
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Ranhui Duan
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
| | - Junqun Fang
- Department of Health Care, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Hua Wang
- Department of Medical Genetics & the Prenatal Diagnosis Center of Hunan Province, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China.,NHC Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
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7
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Kraan CM, Baker EK, Arpone M, Bui M, Ling L, Gamage D, Bretherton L, Rogers C, Field MJ, Wotton TL, Francis D, Hunter MF, Cohen J, Amor DJ, Godler DE. DNA Methylation at Birth Predicts Intellectual Functioning and Autism Features in Children with Fragile X Syndrome. Int J Mol Sci 2020; 21:ijms21207735. [PMID: 33086711 PMCID: PMC7589848 DOI: 10.3390/ijms21207735] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS) is a leading single-gene cause of intellectual disability (ID) with autism features. This study analysed diagnostic and prognostic utility of the Fragile X-Related Epigenetic Element 2 DNA methylation (FREE2m) assessed by Methylation Specific-Quantitative Melt Analysis and the EpiTYPER system, in retrospectively retrieved newborn blood spots (NBS) and newly created dried blood spots (DBS) from 65 children with FXS (~2–17 years). A further 168 NBS from infants from the general population were used to establish control reference ranges, in both sexes. FREE2m analysis showed sensitivity and specificity approaching 100%. In FXS males, NBS FREE2m strongly correlated with intellectual functioning and autism features, however associations were not as strong for FXS females. Fragile X mental retardation 1 gene (FMR1) mRNA levels in blood were correlated with FREE2m in both NBS and DBS, for both sexes. In females, DNAm was significantly increased at birth with a decrease in childhood. The findings support the use of FREE2m analysis in newborns for screening, diagnostic and prognostic testing in FXS.
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Affiliation(s)
- Claudine M Kraan
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
| | - Emma K Baker
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
- School of Psychology and Public Health, La Trobe University, Bundoora VIC 3086, Australia
| | - Marta Arpone
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
- Brain and Mind, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville VIC 3052, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne VIC 3052, Australia;
| | - Ling Ling
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
| | - Dinusha Gamage
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
| | - Lesley Bretherton
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
| | - Carolyn Rogers
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle NSW 2298, Australia; (C.R.); (M.J.F.)
| | - Michael J Field
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle NSW 2298, Australia; (C.R.); (M.J.F.)
| | - Tiffany L Wotton
- New South Wales Newborn Screening Program, Children’s Hospital at Westmead, Sydney NSW 2145, Australia;
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia;
| | - Matt F Hunter
- Monash Genetics, Monash Health, Clayton, VIC 3168, Australia;
| | - Jonathan Cohen
- Centre for Developmental Disability Health Victoria, Monash University, Doveton VIC 3177, Australia;
- Fragile X Alliance Inc., North Caulfield VIC 3161, Australia
| | - David J Amor
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
| | - David E Godler
- Diagnosis and Development, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne VIC 3052, Australia; (C.M.K.); (E.K.B.); (M.A.); (L.L.); (D.G.); (L.B.); (D.J.A.)
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville VIC 3052, Australia
- Correspondence: ; Tel.: +613-8341-6496
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8
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Poeta L, Drongitis D, Verrillo L, Miano MG. DNA Hypermethylation and Unstable Repeat Diseases: A Paradigm of Transcriptional Silencing to Decipher the Basis of Pathogenic Mechanisms. Genes (Basel) 2020; 11:E684. [PMID: 32580525 PMCID: PMC7348995 DOI: 10.3390/genes11060684] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/12/2022] Open
Abstract
Unstable repeat disorders comprise a variable group of incurable human neurological and neuromuscular diseases caused by an increase in the copy number of tandem repeats located in various regions of their resident genes. It has become clear that dense DNA methylation in hyperexpanded non-coding repeats induces transcriptional silencing and, subsequently, insufficient protein synthesis. However, the ramifications of this paradigm reveal a far more profound role in disease pathogenesis. This review will summarize the significant progress made in a subset of non-coding repeat diseases demonstrating the role of dense landscapes of 5-methylcytosine (5mC) as a common disease modifier. However, the emerging findings suggest context-dependent models of 5mC-mediated silencing with distinct effects of excessive DNA methylation. An in-depth understanding of the molecular mechanisms underlying this peculiar group of human diseases constitutes a prerequisite that could help to discover novel pathogenic repeat loci, as well as to determine potential therapeutic targets. In this regard, we report on a brief description of advanced strategies in DNA methylation profiling for the identification of unstable Guanine-Cytosine (GC)-rich regions and on promising examples of molecular targeted therapies for Fragile X disease (FXS) and Friedrich ataxia (FRDA) that could pave the way for the application of this technique in other hypermethylated expansion disorders.
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Affiliation(s)
- Loredana Poeta
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
| | - Denise Drongitis
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
| | - Lucia Verrillo
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, 81100 Caserta, Italy
| | - Maria Giuseppina Miano
- Institute of Genetics and Biophysics “Adriano Buzzati-Traverso”, CNR, 80131 Naples, Italy; (L.P.); (D.D.); (L.V.)
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9
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Abu Diab M, Eiges R. The Contribution of Pluripotent Stem Cell (PSC)-Based Models to the Study of Fragile X Syndrome (FXS). Brain Sci 2019; 9:brainsci9020042. [PMID: 30769941 PMCID: PMC6406836 DOI: 10.3390/brainsci9020042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 02/06/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common heritable form of cognitive impairment. It results from a deficiency in the fragile X mental retardation protein (FMRP) due to a CGG repeat expansion in the 5′-UTR of the X-linked FMR1 gene. When CGGs expand beyond 200 copies, they lead to epigenetic gene silencing of the gene. In addition, the greater the allele size, the more likely it will become unstable and exhibit mosaicism for expansion size between and within tissues in affected individuals. The timing and mechanisms of FMR1 epigenetic gene silencing and repeat instability are far from being understood given the lack of appropriate cellular and animal models that can fully recapitulate the molecular features characteristic of the disease pathogenesis in humans. This review summarizes the data collected to date from mutant human embryonic stem cells, induced pluripotent stem cells, and hybrid fusions, and discusses their contribution to the investigation of FXS, their key limitations, and future prospects.
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Affiliation(s)
- Manar Abu Diab
- Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem 91031, Israel.
- School of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
| | - Rachel Eiges
- Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem 91031, Israel.
- School of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
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10
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Cheng Y, Li Z, Manupipatpong S, Lin L, Li X, Xu T, Jiang YH, Shu Q, Wu H, Jin P. 5-Hydroxymethylcytosine alterations in the human postmortem brains of autism spectrum disorder. Hum Mol Genet 2018; 27:2955-2964. [PMID: 29790956 PMCID: PMC6097011 DOI: 10.1093/hmg/ddy193] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/13/2018] [Accepted: 05/14/2018] [Indexed: 12/26/2022] Open
Abstract
Autism spectrum disorders (ASDs) include a group of syndromes characterized by impaired language, social and communication skills, in addition to restrictive behaviors or stereotypes. However, with a prevalence of 1.5% in developed countries and high comorbidity rates, no clear underlying mechanism that unifies the heterogeneous phenotypes of ASD exists. 5-hydroxymethylcytosine (5hmC) is highly enriched in the brain and recognized as an essential epigenetic mark in developmental and brain disorders. To explore the role of 5hmC in ASD, we used the genomic DNA isolated from the postmortem cerebellum of both ASD patients and age-matched controls to profile genome-wide distribution of 5hmC. We identified 797 age-dependent differentially hydroxymethylated regions (DhMRs) in the young group (age ≤ 18), while no significant DhMR was identified in the groups over 18 years of age. Pathway and disease association analyses demonstrated that the intragenic DhMRs were in the genes involved in cell-cell communication and neurological disorders. Also, we saw significant 5hmC changes in the larger group of psychiatric genes. Interestingly, we found that the predicted cis functions of non-coding intergenic DhMRs strikingly associate with ASD and intellectual disorders. A significant fraction of intergenic DhMRs overlapped with topologically associating domains. These results together suggest that 5hmC alteration is associated with ASD, particularly in the early development stage, and could contribute to the pathogenesis of ASD.
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Affiliation(s)
- Ying Cheng
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Ziyi Li
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Sasicha Manupipatpong
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Li Lin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Xuekun Li
- The Children’s Hospital and Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Tianlei Xu
- Department of Mathematics and Computer Science, Emory University, Atlanta, GA 30322, USA
| | - Yong-Hui Jiang
- Department of Pediatrics, University Program in Genetics and Genomics, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Neurobiology, University Program in Genetics and Genomics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Qiang Shu
- The Children’s Hospital and Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Hao Wu
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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11
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Zhu Q, Stöger R, Alberio R. A Lexicon of DNA Modifications: Their Roles in Embryo Development and the Germline. Front Cell Dev Biol 2018; 6:24. [PMID: 29637072 PMCID: PMC5880922 DOI: 10.3389/fcell.2018.00024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/27/2018] [Indexed: 12/12/2022] Open
Abstract
5-methylcytosine (5mC) on CpG dinucleotides has been viewed as the major epigenetic modification in eukaryotes for a long time. Apart from 5mC, additional DNA modifications have been discovered in eukaryotic genomes. Many of these modifications are thought to be solely associated with DNA damage. However, growing evidence indicates that some base modifications, namely 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), 5-carboxylcytosine (5caC), and N6-methadenine (6mA), may be of biological relevance, particularly during early stages of embryo development. Although abundance of these DNA modifications in eukaryotic genomes can be low, there are suggestions that they cooperate with other epigenetic markers to affect DNA-protein interactions, gene expression, defense of genome stability and epigenetic inheritance. Little is still known about their distribution in different tissues and their functions during key stages of the animal lifecycle. This review discusses current knowledge and future perspectives of these novel DNA modifications in the mammalian genome with a focus on their dynamic distribution during early embryonic development and their potential function in epigenetic inheritance through the germ line.
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Affiliation(s)
- Qifan Zhu
- School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Reinhard Stöger
- School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Ramiro Alberio
- School of Biosciences, University of Nottingham, Nottingham, United Kingdom
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12
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Arpone M, Baker EK, Bretherton L, Bui M, Li X, Whitaker S, Dissanayake C, Cohen J, Hickerton C, Rogers C, Field M, Elliott J, Aliaga SM, Ling L, Francis D, Hearps SJC, Hunter MF, Amor DJ, Godler DE. Intragenic DNA methylation in buccal epithelial cells and intellectual functioning in a paediatric cohort of males with fragile X. Sci Rep 2018; 8:3644. [PMID: 29483611 PMCID: PMC5827525 DOI: 10.1038/s41598-018-21990-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 02/12/2018] [Indexed: 01/05/2023] Open
Abstract
Increased intragenic DNA methylation of the Fragile X Related Epigenetic Element 2 (FREE2) in blood has been correlated with lower intellectual functioning in females with fragile X syndrome (FXS). This study explored these relationships in a paediatric cohort of males with FXS using Buccal Epithelial Cells (BEC). BEC were collected from 25 males with FXS, aged 3 to 17 years and 19 age-matched male controls without FXS. Methylation of 9 CpG sites within the FREE2 region was examined using the EpiTYPER approach. Full Scale IQ (FSIQ) scores of males with FXS were corrected for floor effect using the Whitaker and Gordon (WG) extrapolation method. Compared to controls, children with FXS had significant higher methylation levels for all CpG sites examined (p < 3.3 × 10−7), and within the FXS group, lower FSIQ (WG corrected) was associated with higher levels of DNA methylation, with the strongest relationship found for CpG sites within FMR1 intron 1 (p < 5.6 × 10−5). Applying the WG method to the FXS cohort unmasked significant epi-genotype-phenotype relationships. These results extend previous evidence in blood to BEC and demonstrate FREE2 DNA methylation to be a sensitive epigenetic biomarker significantly associated with the variability in intellectual functioning in FXS.
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Affiliation(s)
- Marta Arpone
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia. .,Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia. .,Child Neuropsychology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.
| | - Emma K Baker
- Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Lesley Bretherton
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Child Neuropsychology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Minh Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia
| | - Xin Li
- Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Simon Whitaker
- School of Human and Health Science, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
| | - Cheryl Dissanayake
- Olga Tennison Autism Research Centre, La Trobe University, Melbourne, VIC, Australia
| | - Jonathan Cohen
- Fragile X Alliance Inc, North Caulfield, VIC, Australia and Centre for Developmental Disability Health Victoria, Monash University, Dandenong, VIC, Australia
| | - Chriselle Hickerton
- Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle, NSW, Australia
| | - Mike Field
- Genetics of Learning Disability Service (GOLD service), Hunter Genetics, Newcastle, NSW, Australia
| | - Justine Elliott
- Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Solange M Aliaga
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.,Centre for Diagnosis and Treatment of Fragile X Syndrome, INTA University of Chile, Santiago, Chile
| | - Ling Ling
- Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - David Francis
- Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Stephen J C Hearps
- Child Neuropsychology, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - Matthew F Hunter
- Monash Genetics, Monash Health, Melbourne, VIC, Australia and Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - David J Amor
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Victorian Clinical Genetics Services and Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
| | - David E Godler
- Faculty of Medicine, Dentistry and Health Sciences, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.,Cyto-Molecular Diagnostics Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
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13
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Davis JK, Broadie K. Multifarious Functions of the Fragile X Mental Retardation Protein. Trends Genet 2017; 33:703-714. [PMID: 28826631 PMCID: PMC5610095 DOI: 10.1016/j.tig.2017.07.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS), a heritable intellectual and autism spectrum disorder (ASD), results from the loss of Fragile X mental retardation protein (FMRP). This neurodevelopmental disease state exhibits neural circuit hyperconnectivity and hyperexcitability. Canonically, FMRP functions as an mRNA-binding translation suppressor, but recent findings have enormously expanded its proposed roles. Although connections between burgeoning FMRP functions remain unknown, recent advances have extended understanding of its involvement in RNA, channel, and protein binding that modulate calcium signaling, activity-dependent critical period development, and the excitation-inhibition (E/I) neural circuitry balance. In this review, we contextualize 3 years of FXS model research. Future directions extrapolated from recent advances focus on discovering links between FMRP roles to determine whether FMRP has a multitude of unrelated functions or whether combinatorial mechanisms can explain its multifaceted existence.
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Affiliation(s)
- Jenna K Davis
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA.
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14
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A C9ORF72 BAC mouse model recapitulates key epigenetic perturbations of ALS/FTD. Mol Neurodegener 2017; 12:46. [PMID: 28606110 PMCID: PMC5468954 DOI: 10.1186/s13024-017-0185-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/30/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Amyotrophic Lateral Sclerosis (ALS) is a fatal and progressive neurodegenerative disorder with identified genetic causes representing a significant minority of all cases. A GGGGCC hexanucleotide repeat expansion (HRE) mutation within the C9ORF72 gene has recently been identified as the most frequent known cause of ALS. The expansion leads to partial heterochromatinization of the locus, yet mutant RNAs and dipeptide repeat proteins (DPRs) are still produced in sufficient quantities to confer neurotoxicity. The levels of these toxic HRE products positively correlate with cellular toxicity and phenotypic severity across multiple disease models. Moreover, the degree of epigenetic repression inversely correlates with some facets of clinical presentation in C9-ALS patients. Recently, bacterial artificial chromosomes (BAC) have been used to generate transgenic mice that harbor the HRE mutation, complementing other relevant model systems such as patient-derived induced pluripotent stem cells (iPSCs). While epigenetic features of the HRE have been investigated in various model systems and post-mortem tissues, epigenetic dysregulation at the expanded locus in C9-BAC mice remains unexplored. METHODS AND RESULTS Here, we sought to determine whether clinically relevant epigenetic perturbations caused by the HRE are mirrored in a C9-BAC mouse model. We used complementary DNA methylation assessment and immunoprecipitation methods to demonstrate that epigenetic aberrations caused by the HRE, such as DNA and histone methylation, are recapitulated in the C9-BAC mice. Strikingly, we found that cytosine hypermethylation within the promoter region of the human transgene occurred in a subset of C9-BAC mice similar to what is observed in patient populations. Moreover, we show that partial heterochromatinization of the C9 HRE occurs during the first weeks of the mouse lifespan, indicating age-dependent epigenetic repression. Using iPSC neurons, we found that preventing R-loop formation did not impede heterochromatinization of the HRE. CONCLUSIONS Taken together, these observations provide further insight into mechanism and developmental time-course of epigenetic perturbations conferred by the C9ORF72 HRE. Finally, we suggest that epigenetic repression of the C9ORF72 HRE and nearby gene promoter could impede or delay motor neuron degeneration in C9-BAC mouse models of ALS/FTD.
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15
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Kong HE, Zhao J, Xu S, Jin P, Jin Y. Fragile X-Associated Tremor/Ataxia Syndrome: From Molecular Pathogenesis to Development of Therapeutics. Front Cell Neurosci 2017; 11:128. [PMID: 28529475 PMCID: PMC5418347 DOI: 10.3389/fncel.2017.00128] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/18/2017] [Indexed: 12/31/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by a premutation CGG repeat expansion (55-200 repeats) within the 5' UTR of the fragile X gene (FMR1). FXTAS is characterized by intension tremor, cerebellar ataxia, progressive neurodegeneration, parkinsonism and cognitive decline. The development of transgenic mouse and Drosophila melanogaster models carrying an expanded CGG repeat has yielded valuable insight into the pathophysiology of FXTAS. To date, we know of two main molecular mechanisms of this disorder: (1) a toxic gain of function of the expanded CGG-repeat FMR1 mRNA, which results in the binding/sequestration of the CGG-binding proteins; and (2) CGG repeat-associated non-AUG-initiated (RAN) translation, which generates a polyglycine peptide toxic to cells. Besides these CGG-mediated mechanisms, recent studies have shed light on additional mechanisms of pathogenesis, such as the antisense transcript ASFMR1, mitochondrial dysfunction, DNA damage from R-loop formation and 5-hydroxymethylcytosine (5hmC)-mediated epigenetic modulation. Here we summarize the recent progress towards understanding the etiology of FXTAS and provide an overview of potential treatment strategies.
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Affiliation(s)
- Ha Eun Kong
- Department of Human Genetics, School of Medicine, Emory UniversityAtlanta, GA, USA
| | - Juan Zhao
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South UniversityChangsha, China
| | - Shunliang Xu
- Department of Neurology, 2nd Hospital of Shandong UniversityJinan, China
| | - Peng Jin
- Department of Human Genetics, School of Medicine, Emory UniversityAtlanta, GA, USA
| | - Yan Jin
- Department of Ophthalmology, Second Hospital, Jilin UniversityChangchun, China
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