1
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Merritt JK, Fang X, Caylor RC, Skinner SA, Friez MJ, Percy AK, Neul JL. Normalized Clinical Severity Scores Reveal a Correlation between X Chromosome Inactivation and Disease Severity in Rett Syndrome. Genes (Basel) 2024; 15:594. [PMID: 38790223 PMCID: PMC11120815 DOI: 10.3390/genes15050594] [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: 03/29/2024] [Revised: 05/01/2024] [Accepted: 05/05/2024] [Indexed: 05/26/2024] Open
Abstract
Rett Syndrome (RTT) is a severe neurodevelopmental disorder predominately diagnosed in females and primarily caused by pathogenic variants in the X-linked gene Methyl-CpG Binding Protein 2 (MECP2). Most often, the disease causing the MECP2 allele resides on the paternal X chromosome while a healthy copy is maintained on the maternal X chromosome with inactivation (XCI), resulting in mosaic expression of one allele in each cell. Preferential inactivation of the paternal X chromosome is theorized to result in reduced disease severity; however, establishing such a correlation is complicated by known MECP2 genotype effects and an age-dependent increase in severity. To mitigate these confounding factors, we developed an age- and genotype-normalized measure of RTT severity by modeling longitudinal data collected in the US Rett Syndrome Natural History Study. This model accurately reflected individual increase in severity with age and preserved group-level genotype specific differences in severity, allowing for the creation of a normalized clinical severity score. Applying this normalized score to a RTT XCI dataset revealed that XCI influence on disease severity depends on MECP2 genotype with a correlation between XCI and severity observed only in individuals with MECP2 variants associated with increased clinical severity. This normalized measure of RTT severity provides the opportunity for future discovery of additional factors contributing to disease severity that may be masked by age and genotype effects.
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Affiliation(s)
- Jonathan K. Merritt
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - Xiaolan Fang
- Department of Pathology, Henry Ford Health System, Detroit, MI 48202, USA;
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Raymond C. Caylor
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Steven A. Skinner
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Michael J. Friez
- Greenwood Genetic Center, Greenwood, SC 29646, USA; (R.C.C.); (S.A.S.); (M.J.F.)
| | - Alan K. Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Jeffrey L. Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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2
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Szelenyi ER, Fisenne D, Knox JE, Harris JA, Gornet JA, Palaniswamy R, Kim Y, Venkataraju KU, Osten P. Distributed X chromosome inactivation in brain circuitry is associated with X-linked disease penetrance of behavior. Cell Rep 2024; 43:114068. [PMID: 38614085 PMCID: PMC11107803 DOI: 10.1016/j.celrep.2024.114068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 02/05/2024] [Accepted: 03/21/2024] [Indexed: 04/15/2024] Open
Abstract
The precise anatomical degree of brain X chromosome inactivation (XCI) that is sufficient to alter X-linked disorders in females is unclear. Here, we quantify whole-brain XCI at single-cell resolution to discover a prevalent activation ratio of maternal to paternal X at 60:40 across all divisions of the adult brain. This modest, non-random XCI influences X-linked disease penetrance: maternal transmission of the fragile X mental retardation 1 (Fmr1)-knockout (KO) allele confers 55% of total brain cells with mutant X-active, which is sufficient for behavioral penetrance, while 40% produced from paternal transmission is tolerated. Local XCI mosaicism within affected maternal Fmr1-KO mice further specifies sensorimotor versus social anxiety phenotypes depending on which distinct brain circuitry is most affected, with only a 50%-55% mutant X-active threshold determining penetrance. Thus, our results define a model of X-linked disease penetrance in females whereby distributed XCI among single cells populating brain circuitries can regulate the behavioral penetrance of an X-linked mutation.
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Affiliation(s)
- Eric R Szelenyi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Program in Neuroscience, Stony Brook University, Neurobiology and Behavior, Stony Brook, NY 11794, USA.
| | - Danielle Fisenne
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Hofstra University, Hempstead, NY 11549, USA; Certerra, Inc., Farmingdale, NY 11735, USA
| | - Joseph E Knox
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Julie A Harris
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - James A Gornet
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Columbia University, New York, NY 10027, USA
| | | | - Yongsoo Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; College of Medicine, Penn State University, Hershey, PA 17033, USA
| | | | - Pavel Osten
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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3
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Nan H, Chu M, Zhang J, Jiang D, Wang Y, Wu L. Okur-Chung neurodevelopmental syndrome: Implications for phenotype and genotype expansion. Mol Genet Genomic Med 2024; 12:e2398. [PMID: 38444259 PMCID: PMC10915366 DOI: 10.1002/mgg3.2398] [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: 09/19/2023] [Revised: 01/17/2024] [Accepted: 01/31/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Okur-Chung neurodevelopmental syndrome (OCNDS) is a rare autosomal dominant disorder caused by pathogenic variants in CSNK2A1. It is characterized by intellectual disability, developmental delay, and multisystemic abnormalities. METHODS We performed the whole-exome sequencing for a patient in a Chinese family. The co-segregation study using the Sanger sequencing method was performed among family members. Reverse transcription and quantitative real-time polymerase chain reaction were carried out using total RNA from blood samples of the proband and wild-type control subjects. A review of patients with OCNDS harboring CSNK2A1 pathogenic variants was conducted through a comprehensive search of the PubMed database. RESULTS We identified a novel CSNK2A1 frameshift variant p.Tyr323Leufs*16 in a Chinese family. The proband, a 31-year-old female, presented with abnormal eating habits, recurrent seizures, language impairment, and intellectual disability. Her mother exhibited postnatal hernias, splenomegaly, and a predisposition to infections, but showed no significant developmental impairments or intellectual disability. Genetic studies revealed the presence of this variant in CSNK2A1 in both the proband and her mother. Transcription analysis revealed this variant may lead to nonsense-mediated mRNA decay, suggesting haploinsufficiency as a potential disease mechanism. We reviewed 47 previously reported OCNDS cases and discovered that individuals carrying CSNK2A1 null variants may exhibit a diminished frequency of symptoms linked to language deficits, dysmorphic facial features, or intellectual disability, consequently presenting an overall milder phenotype when compared to those with missense variants. CONCLUSION We report a novel frameshift variant, p.Tyr323Leufs*16, in an OCNDS family with a generally mild phenotype. This study may broaden the spectrum of clinical presentations associated with OCNDS and contribute novel insights into the genotype-phenotype correlation of this condition.
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Affiliation(s)
- Haitian Nan
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Min Chu
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Jing Zhang
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Deming Jiang
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Yihao Wang
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Liyong Wu
- Department of Neurology, Xuanwu HospitalCapital Medical UniversityBeijingChina
- National Clinical Research Center for Geriatric DiseasesBeijingChina
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4
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Czerwonogrodzka-Senczyna A, Milewska M, Kwiecień P, Szczałuba K. Diet and Nutritional Status of Polish Girls with Rett Syndrome-A Case-Control Study. Nutrients 2023; 15:3334. [PMID: 37571271 PMCID: PMC10420679 DOI: 10.3390/nu15153334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/18/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
(1) Background: Rett syndrome may be considered a disease strongly associated with nutritional disorders that are likely to require special management strategies, extending beyond what is usually required for children with other developmental disorders. The aim of the study was to assess the nutritional status and diet of Polish girls with Rett syndrome. (2) Methods: Each patient (study group = 49, control group = 22) underwent anthropometric measurements, including body weight and height, waist, hip and arm circumference, and skinfold measurement. The assessment of the diet was based on the analysis of 7-day menus and the Food Frequency Questionnaire (FFQ-6). Data were analyzed using Statistica 13.3. (3) Results: The majority of the girls with Rett syndrome were deficient in weight and height, and consumed fewer calories, less protein, dietary fiber, calcium, and iron than the control group. They also drank less fluid. Soft products that were easy to chew and considered to be high in energy value were significantly more common in the menus. (4) Conclusions: Girls with Rett syndrome are characterized by weight deficiencies, poor growth that deteriorates with age, and are at risk of food shortages. Various nutritional intervention strategies should be explored to reduce and, if possible, prevent malnutrition and cachexia in such patients.
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Affiliation(s)
| | - Magdalena Milewska
- Department of Clinical Dietetics, Faculty of Health Sciences, Medical University of Warsaw, 01-445 Warsaw, Poland;
| | | | - Krzysztof Szczałuba
- Department of Medical Genetics, 1st Faculty of Medicine, Medical University of Warsaw, 01-445 Warsaw, Poland;
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5
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Coorey B, Haase F, Ellaway C, Clarke A, Lisowski L, Gold WA. Gene Editing and Rett Syndrome: Does It Make the Cut? CRISPR J 2022; 5:490-499. [PMID: 35881862 DOI: 10.1089/crispr.2022.0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Rett syndrome (RTT) is a rare neurogenetic disorder caused by pathogenic variants of the Methyl CpG binding protein 2 (MECP2) gene. The RTT is characterized by apparent normal early development followed by regression of communicative and fine motor skills. Comorbidities include epilepsy, severe cognitive impairment, and autonomic and motor dysfunction. Despite almost 60 clinical trials and the promise of a gene therapy, no cure has yet emerged with treatment remaining symptomatic. Advances in understanding RTT has provided insight into the complexity and exquisite control of MECP2 expression, where loss of expression leads to RTT and overexpression leads to MECP2 duplication syndrome. Therapy development requires regulated expression that matches the spatiotemporal endogenous expression of MECP2 in the brain. Gene editing has revolutionized gene therapy and promises an exciting strategy for many incurable monogenic disorders, including RTT, by editing the native locus and retaining endogenous gene expression. Here, we review the literature on the currently available editing technologies and discuss their limitations and applicability to the treatment of RTT.
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Affiliation(s)
- Bronte Coorey
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, Australia.,Molecular Neurobiology Research Laboratory, Kid's Research, Westmead, Australia.,Kids Neuroscience Centre, Kids Research, Children's Hospital at Westmead, Westmead, Australia
| | - Florencia Haase
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, Australia.,Molecular Neurobiology Research Laboratory, Kid's Research, Westmead, Australia.,Kids Neuroscience Centre, Kids Research, Children's Hospital at Westmead, Westmead, Australia
| | - Carolyn Ellaway
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network Sydney, Westmead, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Angus Clarke
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Leszek Lisowski
- Translational Vectorology Research Unit, Children's Medical Research Institute, The University of Sydney, Westmead, Australia.,Vector and Genome Engineering Facility, Children's Medical Research Institute, The University of Sydney, Westmead, Australia.,Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine, Warsaw, Poland
| | - Wendy A Gold
- Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, Australia.,Molecular Neurobiology Research Laboratory, Kid's Research, Westmead, Australia.,Kids Neuroscience Centre, Kids Research, Children's Hospital at Westmead, Westmead, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia.,Children's Medical Research Institute, Westmead, Australia
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6
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Zwilling M, Romano A, Favetta M, Ippolito E, Lotan M. Impact of a Remotely Supervised Motor Rehabilitation Program on Maternal Well-Being During the COVID-19 Italian Lockdown. Front Psychol 2022; 13:834419. [PMID: 35345633 PMCID: PMC8957072 DOI: 10.3389/fpsyg.2022.834419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
COVID-19 Lockdown was particularly challenging for most mothers of people with intellectual disabilities, including those with Rett syndrome (RTT), leading to feelings of abandonment from healthcare services of their children. Within those days, telerehabilitation has represented a valid alternative to support physical activity and treatment, supporting parents in structuring their children’s daily routine at home. This article aims to describe the well-being level of two groups of mothers of girls and women with RTT who were involved in a home-based remotely supervised motor rehabilitation program, respectively, before and during the COVID-19 Italian lockdown. Forty participants with classic RTT were recruited before the lockdown and randomly assigned to two groups that performed the intervention immediately before (Group 1) and during (Group 2) the lockdown, respectively. The intervention included an individualized daily physical activity program carried out for 12 weeks by participants’ parents and fortnightly supervised throughout Skype contacts to plan, monitor, and accommodate individual activities in the participant’s life at home. The short form Caregivers Well-Being Scale was collected for the mothers in each group 12 weeks before intervention (T1), at intervention initiation (T2), immediately after intervention termination (T3), as well as at 12 weeks after intervention termination (T4). Mothers of participants in the Group 1 showed a stable level of well-being across all four evaluations with a slight improvement during the lockdown, without significant change. Similarly, the well-being level of mothers in the Group 2 showed a statistically significant increase in their well-being between T2 and T3 (during the lockdown) and its reduction to the pre-intervention level between T3 and T4 (after the lockdown). The results suggest that the lockdown did not negatively affect the participants’ mothers’ well-being, leading to its improvement. Moreover, the proposed intervention could have supported the mothers in managing the new daily routine at home, positively affecting maternal well-being.
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Affiliation(s)
- Moti Zwilling
- Department of Economics and Business Administration, Ariel University, Ari'el, Israel
| | - Alberto Romano
- Department of Health System Management, Ariel University, Ari'el, Israel.,Movement Analysis and Robotics Laboratory, Unit of Neurorehabilitation, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy.,Centro AIRETT Ricerca e Innovazione (CARI), Research and Innovation Airett Center, Verona, Italy
| | - Martina Favetta
- Movement Analysis and Robotics Laboratory, Unit of Neurorehabilitation, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Meir Lotan
- Department of Physiotherapy, Ariel University, Ari'el, Israel.,Israeli Rett Syndrome National Evaluation Team, Sheba Hospital, Ramat-Gan, Israel
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7
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Lotan M, Ippolito E, Favetta M, Romano A. Skype Supervised, Individualized, Home-Based Rehabilitation Programs for Individuals With Rett Syndrome and Their Families - Parental Satisfaction and Point of View. Front Psychol 2021; 12:720927. [PMID: 34603144 PMCID: PMC8481588 DOI: 10.3389/fpsyg.2021.720927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/19/2021] [Indexed: 11/23/2022] Open
Abstract
Individuals with Rett syndrome (RTT) experience impaired gross motor skills limiting their capacity. Therefore, they need support to participate in physical activities, and it is crucial to work with primary caregivers when developing appropriate strategies, thereby leading to an active lifestyle. There is limited evidence supporting the effectiveness of remotely supported physical activity interventions. This project aimed to evaluate the effects of a skype-based, telehealth-delivered physical activity program carried out by participants’ parents at home. This article will focus on parental points of view. A mixed-methods design evaluating parental satisfaction was conducted. Forty participants with a confirmed genetic diagnosis of RTT and their families were recruited. The intervention included a 12-week individualized daily physical activity program carried out by participants’ parents and bi-weekly supervised by expert therapists. Parents’ impressions and feelings related to the program implementation were collected throughout semi-structured interviews, and an ad hoc developed questionnaire and discussed. The current project results suggest that a remote physical rehabilitation program, supported fortnightly by video calls, represents an effective way of conducting a remote physical therapy intervention for this population and that it can be easily carried out at home by primary caregivers, promoting positive functional changes, without bringing feelings of frustration due to the required workload. The strategies that families have learned during the program to support the motor activities of their daughters represent an easily performed set of tools that they can maintain and use in everyday life even after the cessation of the program.
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Affiliation(s)
- Meir Lotan
- Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel.,Israeli Rett Syndrome National Evaluation Team, Sheba Hospital, Ramat-Gan, Israel
| | | | - Martina Favetta
- Motion Analysis and Robotics Laboratory, Unit of Neurorehabilitation, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy
| | - Alberto Romano
- SMART Learning Center, Milan, Italy.,Motion Analysis and Robotics Laboratory, Unit of Neurorehabilitation, Department of Neuroscience, Bambino Gesù Children's Hospital, Rome, Italy.,Centro AIRETT Ricerca e Innovazione (CARI), Research and Innovation Airett Center, Verona, Italy
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8
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Ibrahim A, Papin C, Mohideen-Abdul K, Le Gras S, Stoll I, Bronner C, Dimitrov S, Klaholz BP, Hamiche A. MeCP2 is a microsatellite binding protein that protects CA repeats from nucleosome invasion. Science 2021; 372:372/6549/eabd5581. [PMID: 34324427 DOI: 10.1126/science.abd5581] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 05/06/2021] [Indexed: 12/14/2022]
Abstract
The Rett syndrome protein MeCP2 was described as a methyl-CpG-binding protein, but its exact function remains unknown. Here we show that mouse MeCP2 is a microsatellite binding protein that specifically recognizes hydroxymethylated CA repeats. Depletion of MeCP2 alters chromatin organization of CA repeats and lamina-associated domains and results in nucleosome accumulation on CA repeats and genome-wide transcriptional dysregulation. The structure of MeCP2 in complex with a hydroxymethylated CA repeat reveals a characteristic DNA shape, with considerably modified geometry at the 5-hydroxymethylcytosine, which is recognized specifically by Arg133, a key residue whose mutation causes Rett syndrome. Our work identifies MeCP2 as a microsatellite DNA binding protein that targets the 5hmC-modified CA-rich strand and maintains genome regions nucleosome-free, suggesting a role for MeCP2 dysfunction in Rett syndrome.
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Affiliation(s)
- Abdulkhaleg Ibrahim
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France.,Department of Functional Genomics and Cancer, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France.,Biotechnology Research Center (BTRC), 30303 Tripoli, Libya
| | - Christophe Papin
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France.,Department of Functional Genomics and Cancer, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Kareem Mohideen-Abdul
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France.,Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France
| | - Stéphanie Le Gras
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Isabelle Stoll
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France.,Department of Functional Genomics and Cancer, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Christian Bronner
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France.,Department of Functional Genomics and Cancer, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France
| | - Stefan Dimitrov
- Université Grenoble Alpes, CNRS UMR 5309, INSERM U1209, Institute for Advanced Biosciences (IAB), Site Santé - Allée des Alpes, 38700 La Tronche, France. .,Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Bruno P Klaholz
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France. .,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France.,Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France
| | - Ali Hamiche
- Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 67400 Illkirch, France. .,Department of Functional Genomics and Cancer, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique (CNRS), UMR 7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U964, 67404 Illkirch, France.,Université de Strasbourg, 67404 Illkirch, France.,Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch, France.,Center of Excellence in Bionanoscience Research, King Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia
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9
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Brand BA, Blesson AE, Smith-Hicks CL. The Impact of X-Chromosome Inactivation on Phenotypic Expression of X-Linked Neurodevelopmental Disorders. Brain Sci 2021; 11:brainsci11070904. [PMID: 34356138 PMCID: PMC8305405 DOI: 10.3390/brainsci11070904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 12/20/2022] Open
Abstract
Nearly 20% of genes located on the X chromosome are associated with neurodevelopmental disorders (NDD) due to their expression and role in brain functioning. Given their location, several of these genes are either subject to or can escape X-chromosome inactivation (XCI). The degree to which genes are subject to XCI can influence the NDD phenotype between males and females. We provide a general review of X-linked NDD genes in the context of XCI and detailed discussion of the sex-based differences related to MECP2 and FMR1, two common X-linked causes of NDD that are subject to XCI. Understanding the effects of XCI on phenotypic expression of NDD genes may guide the development of stratification biomarkers in X-linked disorders.
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Affiliation(s)
- Boudewien A Brand
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Alyssa E Blesson
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Constance L. Smith-Hicks
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Correspondence:
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10
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Collins BE, Merritt JK, Erickson KR, Neul JL. Safety and efficacy of genetic MECP2 supplementation in the R294X mouse model of Rett syndrome. GENES, BRAIN, AND BEHAVIOR 2021; 21:e12739. [PMID: 33942492 PMCID: PMC8563491 DOI: 10.1111/gbb.12739] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 01/03/2023]
Abstract
Rett syndrome is a neurodevelopmental disorder caused predominantly by loss-of-function mutations in MECP2, encoding transcriptional modulator methyl-CpG-binding protein 2 (MeCP2). Although no disease-modifying therapies exist at this time, some proposed therapeutic strategies aim to supplement the mutant allele with a wild-type allele producing typical levels of functional MeCP2, such as gene therapy. Because MECP2 is a dosage-sensitive gene, with both loss and gain of function causing disease, these approaches must achieve a narrow therapeutic window to be both safe and effective. While MeCP2 supplementation rescues RTT-like phenotypes in mouse models, the tolerable threshold of MeCP2 is not clear, particularly for partial loss-of-function mutations. We assessed the safety of genetically supplementing full-length human MeCP2 in the context of the R294X allele, a common partial loss-of-function mutation retaining DNA-binding capacity. We assessed the potential for adverse effects from MeCP2 supplementation of a partial loss-of-function mutant and the potential for dominant negative interactions between mutant and full-length MeCP2. In male hemizygous R294X mice, MeCP2 supplementation rescued RTT-like behavioral phenotypes and did not elicit behavioral evidence of excess MeCP2. In female heterozygous R294X mice, RTT-specific phenotypes were similarly rescued. However, MeCP2 supplementation led to evidence of excess MeCP2 activity in a motor coordination assay, suggesting that the underlying motor circuitry is particularly sensitive to MeCP2 dosage in females. These results show that genetic supplementation of full-length MeCP2 is safe in males and largely so females. However, careful consideration of risk for adverse motor effects may be warranted for girls and women with RTT.
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Affiliation(s)
| | - Jonathan K. Merritt
- Department of PediatricsVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Kirsty R. Erickson
- Department of PediatricsVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Jeffrey L. Neul
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special EducationVanderbilt University Medical Center and Vanderbilt UniversityNashvilleTennesseeUSA
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11
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Thapa S, Venkatachalam A, Khan N, Naqvi M, Balderas M, Runge JK, Haag A, Hoch KM, Glaze DG, Luna RA, Motil KJ. Assessment of the gut bacterial microbiome and metabolome of girls and women with Rett Syndrome. PLoS One 2021; 16:e0251231. [PMID: 33956889 PMCID: PMC8101921 DOI: 10.1371/journal.pone.0251231] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/22/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Gastrointestinal problems affect the health and quality of life of individuals with Rett syndrome (RTT) and pose a medical hardship for their caregivers. We hypothesized that the variability in the RTT phenotype contributes to the dysbiosis of the gut microbiome and metabolome in RTT, predisposing these individuals to gastrointestinal dysfunction. OBJECTIVES We characterized the gut bacterial microbiome and metabolome in girls and young women with RTT (n = 44) and unaffected controls (n = 21), and examined the relation between the composition of the microbiome and variations in the RTT phenotype. METHODS Demographics and clinical information, including growth and anthropometric measurements, pubertal status, symptoms, clinical severity score, bowel movement, medication use, and dietary intakes were collected from the participants. Fecal samples were collected for analysis of the gut microbiome using Illumina MiSeq-based next-generation sequencing of the 16S rRNA gene followed by bioinformatics analysis of microbial composition, diversity, and community structure. Selected end-products of microbial protein metabolism were characterized by liquid chromatography-mass spectrometry. RESULTS The gut bacterial microbiome differed within the RTT cohort based on pubertal status (p<0.02) and clinical severity scores (p<0.02) of the individuals and the type of diet (p<0.01) consumed. Although the composition of the gut microbiome did not differ between RTT and unaffected individuals, concentrations of protein end-products of the gut bacterial metabolome, including γ-aminobutyric acid (GABA) (p<0.001), tyrosine (p<0.02), and glutamate (p<0.06), were lower in the RTT cohort. Differences in the microbiome within RTT groups, based on symptomatic anxiety, hyperventilation, abdominal distention, or changes in stool frequency and consistency, were not detected. CONCLUSIONS Although variability in the RTT phenotype contributes to the dysbiosis of the gut microbiome, we presently cannot infer causality between gut bacterial dysbiosis and gastrointestinal dysfunction. Nevertheless, alterations in the gut metabolome may provide clues to the pathophysiology of gastrointestinal problems in RTT.
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Affiliation(s)
- Santosh Thapa
- Department of Pathology, Medical Metagenomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alamelu Venkatachalam
- Department of Pathology, Medical Metagenomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Nabeel Khan
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mohammed Naqvi
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Miriam Balderas
- Department of Pathology, Medical Metagenomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jessica K. Runge
- Department of Pathology, Medical Metagenomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anthony Haag
- Department of Pathology, Metabolomics and Proteomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Kathleen M. Hoch
- Department of Pathology, Metabolomics and Proteomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Daniel G. Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neurology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ruth Ann Luna
- Department of Pathology, Medical Metagenomics Laboratory, Texas Children’s Microbiome Center, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kathleen J. Motil
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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12
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Motil KJ, Khan N, Coon JL, Barrish JO, Suter B, Pehlivan D, Schultz RJ, Glaze DG. Gastrointestinal Health Questionnaire for Rett Syndrome: Tool Development. J Pediatr Gastroenterol Nutr 2021; 72:354-360. [PMID: 32969958 DOI: 10.1097/mpg.0000000000002951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVES We report the development and validation of a tool to assess gastrointestinal health in Rett syndrome (RTT). We hypothesized that the Gastrointestinal Health Questionnaire (GHQ) is a valid clinical outcomes measure of gastrointestinal health in RTT. PATIENTS AND METHODS We used parent interviews, surveys, and literature review to generate a questionnaire related to gastrointestinal health and function, mood and behaviors, and parental concerns for individuals with RTT. Parents of affected and unaffected individuals provided responses to the GHQ, assessed the relevance and importance of statements, and completed 5 surveys related to gastrointestinal health, child-related mood and behaviors, and parent concerns. We used multivariate item analysis, 2-sample t tests, and correlations to assess the validity of the GHQ. RESULTS We documented acceptable internal consistency of statements related to gastrointestinal health and function (Cronbach-α = 0.91), RTT-related mood and behaviors (Cronbach-α = 0.89), and parent concerns (Cronbach-α = 0.95) in the GHQ. We documented favorable external validity based on differences in response scores between parents of affected and unaffected individuals (P < 0.001) and correlations in parental response scores between the GHQ and 5 validated questionnaires addressing similar issues (P < 0.001). CONCLUSION The GHQ is a valid tool for the assessment of gastrointestinal health in RTT and offers the opportunity to field test the safety and efficacy of novel drug therapies in clinical trials for individuals affected with this disorder.
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Affiliation(s)
- Kathleen J Motil
- USDA/ARS Children's Nutrition Research Center
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
| | - Nabeel Khan
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
| | - Jennifer L Coon
- USDA/ARS Children's Nutrition Research Center
- Department of Pediatrics, Baylor College of Medicine
| | - Judy O Barrish
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
| | - Bernhard Suter
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
| | - Davut Pehlivan
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
| | - Rebecca J Schultz
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
- Texas Woman's University, Houston, TX
| | - Daniel G Glaze
- Texas Children's Hospital
- Department of Pediatrics, Baylor College of Medicine
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13
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Unraveling Molecular Pathways Altered in MeCP2-Related Syndromes, in the Search for New Potential Avenues for Therapy. Biomedicines 2021; 9:biomedicines9020148. [PMID: 33546327 PMCID: PMC7913493 DOI: 10.3390/biomedicines9020148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/25/2021] [Accepted: 01/30/2021] [Indexed: 12/27/2022] Open
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is an X-linked epigenetic modulator whose dosage is critical for neural development and function. Loss-of-function mutations in MECP2 cause Rett Syndrome (RTT, OMIM #312750) while duplications in the Xq28 locus containing MECP2 and Interleukin-1 receptor-associated kinase 1 (IRAK1) cause MECP2 duplication syndrome (MDS, OMIM #300260). Both are rare neurodevelopmental disorders that share clinical symptoms, including intellectual disability, loss of speech, hand stereotypies, vasomotor deficits and seizures. The main objective of this exploratory study is to identify novel signaling pathways and potential quantitative biomarkers that could aid early diagnosis and/or the monitoring of disease progression in clinical trials. We analyzed by RT-PCR gene expression in whole blood and microRNA (miRNA) expression in plasma, in a cohort of 20 females with Rett syndrome, 2 males with MECP2 duplication syndrome and 28 healthy controls, and correlated RNA expression with disease and clinical parameters. We have identified a set of potential biomarker panels for RTT diagnostic and disease stratification of patients with microcephaly and vasomotor deficits. Our study sets the basis for larger studies leading to the identification of specific miRNA signatures for early RTT detection, stratification, disease progression and segregation from other neurodevelopmental disorders. Nevertheless, these data will require verification and validation in further studies with larger sample size including a whole range of ages.
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14
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Ehrhart F, Jacobsen A, Rigau M, Bosio M, Kaliyaperumal R, Laros JFJ, Willighagen EL, Valencia A, Roos M, Capella-Gutierrez S, Curfs LMG, Evelo CT. A catalogue of 863 Rett-syndrome-causing MECP2 mutations and lessons learned from data integration. Sci Data 2021; 8:10. [PMID: 33452270 PMCID: PMC7810705 DOI: 10.1038/s41597-020-00794-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/30/2020] [Indexed: 11/09/2022] Open
Abstract
Rett syndrome (RTT) is a rare neurological disorder mostly caused by a genetic variation in MECP2. Making new MECP2 variants and the related phenotypes available provides data for better understanding of disease mechanisms and faster identification of variants for diagnosis. This is, however, currently hampered by the lack of interoperability between genotype-phenotype databases. Here, we demonstrate on the example of MECP2 in RTT that by making the genotype-phenotype data more Findable, Accessible, Interoperable, and Reusable (FAIR), we can facilitate prioritization and analysis of variants. In total, 10,968 MECP2 variants were successfully integrated. Among these variants 863 unique confirmed RTT causing and 209 unique confirmed benign variants were found. This dataset was used for comparison of pathogenicity predicting tools, protein consequences, and identification of ambiguous variants. Prediction tools generally recognised the RTT causing and benign variants, however, there was a broad range of overlap Nineteen variants were identified that were annotated as both disease-causing and benign, suggesting that there are additional factors in these cases contributing to disease development. Measurement(s) | Rett syndrome • phenotype • MECP2 Gene | Technology Type(s) | digital curation • network analysis | Sample Characteristic - Organism | Homo sapiens |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.13359476
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Affiliation(s)
- Friederike Ehrhart
- Department of Bioinformatics - BiGCaT, NUTRIM School of Nutrition and Translational Research in Metabolism, MHeNS School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands. .,GKC - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Annika Jacobsen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Maria Rigau
- Barcelona Supercomputing Centre (BSC), Barcelona, Spain
| | - Mattia Bosio
- Barcelona Supercomputing Centre (BSC), Barcelona, Spain
| | - Rajaram Kaliyaperumal
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeroen F J Laros
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Egon L Willighagen
- Department of Bioinformatics - BiGCaT, NUTRIM School of Nutrition and Translational Research in Metabolism, MHeNS School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Alfonso Valencia
- Barcelona Supercomputing Centre (BSC), Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Marco Roos
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Leopold M G Curfs
- GKC - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Chris T Evelo
- Department of Bioinformatics - BiGCaT, NUTRIM School of Nutrition and Translational Research in Metabolism, MHeNS School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.,GKC - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
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15
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Sabitha KR, Shetty AK, Upadhya D. Patient-derived iPSC modeling of rare neurodevelopmental disorders: Molecular pathophysiology and prospective therapies. Neurosci Biobehav Rev 2020; 121:201-219. [PMID: 33370574 DOI: 10.1016/j.neubiorev.2020.12.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 12/12/2022]
Abstract
The pathological alterations that manifest during the early embryonic development due to inherited and acquired factors trigger various neurodevelopmental disorders (NDDs). Besides major NDDs, there are several rare NDDs, exhibiting specific characteristics and varying levels of severity triggered due to genetic and epigenetic anomalies. The rarity of subjects, paucity of neural tissues for detailed analysis, and the unavailability of disease-specific animal models have hampered detailed comprehension of rare NDDs, imposing heightened challenge to the medical and scientific community until a decade ago. The generation of functional neurons and glia through directed differentiation protocols for patient-derived iPSCs, CRISPR/Cas9 technology, and 3D brain organoid models have provided an excellent opportunity and vibrant resource for decoding the etiology of brain development for rare NDDs caused due to monogenic as well as polygenic disorders. The present review identifies cellular and molecular phenotypes demonstrated from patient-derived iPSCs and possible therapeutic opportunities identified for these disorders. New insights to reinforce the existing knowledge of the pathophysiology of these disorders and prospective therapeutic applications are discussed.
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Affiliation(s)
- K R Sabitha
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M University College of Medicine, College Station, TX, USA.
| | - Dinesh Upadhya
- Centre for Molecular Neurosciences, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
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16
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Scrutinizing the molecular, biochemical, and cytogenetic attributes in subjects with Rett syndrome (RTT) and their mothers. Epilepsy Behav 2020; 111:107277. [PMID: 32653844 DOI: 10.1016/j.yebeh.2020.107277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 11/21/2022]
Abstract
Rett syndrome (RTT) is a stern dominant progressive neurological development disorder linked with X chromosome ranking second for mental slowdown, exclusively in females after few months of birth with normal development and growth period. Genetically any defects in universally expressed methyl-CpG binding protein 2 (MeCP2) transcription regulator gene are considered as radix for RTT in almost all the previous studies. Our study mainly focuses in unraveling the genetic alterations like identifying MeCP2 gene polymorphisms, chromosomal abnormalities, or X-chromosome inactivation (XCI) as underlying cause of RTT in prototypes sorted through Diagnostic and Statistical Manual of Mental Disorders-Text Revised (DSM IV). In addition, we have examined the probable surrogates of brain function disabilities like serotonin, homocysteine (Hcy), calcium, potassium, and lead from blood in both RTT porotypes and their mothers. In our investigation, we have observed varied amino acid substitution of MeCP2 and varied frequency of skewed XCI in RTT prototype. Our study validates that the demonstration of chromosomal analysis, biochemical analysis, and genomic observations helps in concluding RTT condition and can be helpful in providing appropriate treatment and counseling as well as improve the currently available protocol of diagnosis.
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17
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Imamura T, Nakayama T, Nakayama J, Iwasaki N. A Patient with Rett Syndrome Maintained Motor Function by Periodic Rehabilitation Therapy and Proactive Daily Activities. Prog Rehabil Med 2020; 5:20200014. [PMID: 32844127 PMCID: PMC7429559 DOI: 10.2490/prm.20200014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/01/2020] [Indexed: 12/23/2022] Open
Abstract
Background The motor functions of Rett syndrome patients degrade during the course of the disease. Some patients, however, are able to maintain their motor functions by undertaking exercise programs. Case A 2-year-old girl was diagnosed with Rett syndrome after the identification of a mutation in the gene encoding the methyl-CpG-binding protein. The patient started weekly rehabilitation therapy; however, over time, this reduced to monthly sessions, and subsequently, because of worsening epileptic seizures, even fewer sessions were possible. When the patient was 12 years old, intensive rehabilitation therapy was undertaken for 1 month; therapy involved 80 min of in-hospital therapy on weekdays and walking exercises at home at the weekend. An accelerometer (Actiwatch 2, standard type, Philips Respironics) indicated that more than 60 min of daily training at an intensity of 3 metabolic equivalents (METs) or more was achieved at weekends. The patient took the 10-m walk test, and the average time reduced from 18.6 to 13.5 s and the number of steps reduced from 32 to 23 between the start and finish of the first 1-month intensive training regime. After being discharged from the hospital, the patient maintained walking exercises at school during weekdays and performed more than 50 min/day of activity at at least 3 METs at home on weekends, in addition to a weekly home-visit rehabilitation therapy and the annual in-hospital 1-month rehabilitation therapy. Four years later, the patent's average time and number of steps required to walk 10 m remained lower (12.7 s, 24 steps) than those recorded at the first evaluation. Discussion Periodic rehabilitation therapy and proactive walking exercises at more than 3 METs for a duration of up to 50 min/day were instrumental in maintaining the motor functions of a Rett syndrome patient.
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Affiliation(s)
| | - Tomohiro Nakayama
- Division of Pediatric Medicine, Ibaraki Prefectural University of Health Sciences Hospital, Ami, Japan
| | - Junko Nakayama
- Division of Pediatric Medicine, Ibaraki Prefectural University of Health Sciences Hospital, Ami, Japan
| | - Nobuaki Iwasaki
- Division of Pediatric Medicine, Ibaraki Prefectural University of Health Sciences Hospital, Ami, Japan
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18
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Sharaf-Eldin WE, Soliman HN, Abdel-Aziz NN, Elbendary HM, Issa MY, Zaki MS. Mutation spectrum in the gene encoding methyl-CpG-binding protein 2 in Egyptian patients with Rett syndrome. Meta Gene 2020. [DOI: 10.1016/j.mgene.2019.100620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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19
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Wagner MA, Erickson KI, Bender CM, Conley YP. The Influence of Physical Activity and Epigenomics On Cognitive Function and Brain Health in Breast Cancer. Front Aging Neurosci 2020; 12:123. [PMID: 32457596 PMCID: PMC7225270 DOI: 10.3389/fnagi.2020.00123] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/14/2020] [Indexed: 12/17/2022] Open
Abstract
The risk of breast cancer increases with age, with the majority of women diagnosed with breast cancer being postmenopausal. It has been estimated that 25-75% of women with breast cancer experience changes in cognitive function (CF) related to disease and treatment, which compromises psychological well-being, decision making, ability to perform daily activities, and adherence to cancer therapy. Unfortunately, the mechanisms that underlie neurocognitive changes in women with breast cancer remain poorly understood, which in turn limits the development of effective treatments and prevention strategies. Exercise has great potential as a non-pharmaceutical intervention to mitigate the decline in CF in women with breast cancer. Evidence suggests that DNA methylation, an epigenetic mechanism for gene regulation, impacts CF and brain health (BH), that exercise influences DNA methylation, and that exercise impacts CF and BH. Although investigating DNA methylation has the potential to uncover the biologic foundations for understanding neurocognitive changes within the context of breast cancer and its treatment as well as the ability to understand how exercise mitigates these changes, there is a dearth of research on this topic. The purpose of this review article is to compile the research in these areas and to recommend potential areas of opportunity for investigation.
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Affiliation(s)
- Monica A. Wagner
- School of Nursing, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kirk I. Erickson
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, United States
- Discipline of Exercise Science, College of Science, Health, Engineering and Education, Murdoch University, Perth Campus, Murdoch, WA, Australia
| | | | - Yvette P. Conley
- School of Nursing, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, United States
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20
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Carroll MS, Ramirez JM, Weese-Mayer DE. Diurnal variation in autonomic regulation among patients with genotyped Rett syndrome. J Med Genet 2020; 57:786-793. [PMID: 32156713 DOI: 10.1136/jmedgenet-2019-106601] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/07/2020] [Accepted: 02/05/2020] [Indexed: 01/03/2023]
Abstract
BACKGROUND Rett syndrome is a severe neurological disorder with a range of disabling autonomic and respiratory symptoms and resulting predominantly from variants in the methyl-CpG binding protein 2 gene on the long arm of the X-chromosome. As basic research begins to suggest potential treatments, sensitive measures of the dynamic phenotype are needed to evaluate the results of these research efforts. Here we test the hypothesis that the physiological fingerprint of Rett syndrome in a naturalistic environment differs from that of controls, and differs among genotypes within Rett syndrome. METHODS A comprehensive array of heart rate variability, cardiorespiratory coupling and cardiac repolarisation measures were evaluated from an existing database of overnight and daytime inhome ambulatory recordings in 47 cases and matched controls. RESULTS Differences between girls with Rett syndrome and matched controls were apparent in a range of autonomic measures, and suggest a shift towards sympathetic activation and/or parasympathetic inactivation. Daily temporal trends analysed in the context of circadian rhythms reveal alterations in amplitude and phase of diurnal patterns of autonomic balance. Further analysis by genotype class confirms a graded presentation of the Rett syndrome phenotype such that patients with early truncating mutations were most different from controls, while late truncating and missense mutations were least different from controls. CONCLUSIONS Comprehensive autonomic measures from extensive inhome physiological measurements can detect subtle variations in the phenotype of girls with Rett syndrome, suggesting these techniques are suitable for guiding novel therapies.
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Affiliation(s)
- Michael Sean Carroll
- Data Analytics and Reporting, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA .,Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Neurological Surgery, University of Washington, Seattle, Washington, USA
| | - Debra E Weese-Mayer
- Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Division of Autonomic Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
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21
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Mah W, Won H. The three-dimensional landscape of the genome in human brain tissue unveils regulatory mechanisms leading to schizophrenia risk. Schizophr Res 2020; 217:17-25. [PMID: 30894290 PMCID: PMC6748876 DOI: 10.1016/j.schres.2019.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/27/2019] [Accepted: 03/06/2019] [Indexed: 12/18/2022]
Abstract
Recent advances in our understanding of the genetic architecture of schizophrenia have shed light on the schizophrenia etiology. While common variation is one of the major genetic contributors, the majority of common variation reside in non-coding genome, posing a significant challenge in understanding the functional impact of this class of genetic variation. Functional genomic datasets that range from expression quantitative trait loci (eQTL) to chromatin interactions are critical to identify the potential target genes and functional consequences of non-coding variation. In this review, we discuss how three-dimensional chromatin landscape, identified by a technique called Hi-C, has facilitated the identification of potential target genes impacting schizophrenia risk. We outline key steps for Hi-C driven gene mapping, and compare Hi-C defined schizophrenia risk genes defined across developmental epochs and cell types, which offer rich insights into the temporal window and cellular etiology of schizophrenia. In contrast with a neurodevelopmental hypothesis in schizophrenia, Hi-C defined schizophrenia risk genes are postnatally enriched, suggesting that postnatal development is also important for schizophrenia pathogenesis. Moreover, Hi-C defined schizophrenia risk genes are highly expressed in excitatory neurons, highlighting excitatory neurons as a central cell type for schizophrenia. Further characterization of Hi-C defined schizophrenia risk genes demonstrated enrichment for genes that harbor loss-of-function variation in neurodevelopmental disorders, suggesting a shared genetic etiology between schizophrenia and neurodevelopmental disorders. Collectively, moving the search space from risk variants to the target genes lays a foundation to understand the neurobiological basis of schizophrenia.
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Affiliation(s)
- Won Mah
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hyejung Won
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA.
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22
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Ribeiro MC, MacDonald JL. Sex differences in Mecp2-mutant Rett syndrome model mice and the impact of cellular mosaicism in phenotype development. Brain Res 2020; 1729:146644. [PMID: 31904347 DOI: 10.1016/j.brainres.2019.146644] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/08/2019] [Accepted: 12/31/2019] [Indexed: 12/29/2022]
Abstract
There is currently no effective treatment for Rett syndrome (RTT), a severe X-linked progressive neurodevelopmental disorder caused by mutations in the transcriptional regulator MECP2. Because MECP2 is subjected to X-inactivation, most affected individuals are female heterozygotes who display cellular mosaicism for normal and mutant MECP2. Males who are hemizygous for mutant MECP2 are more severely affected than heterozygous females and rarely survive. Mecp2 loss-of-function is less severe in mice, however, and male hemizygous null mice not only survive until adulthood, they have been the most commonly studied model system. Although heterozygous female mice better recapitulate human RTT, they have not been as thoroughly characterized. This is likely because of the added experimental challenges that they present, including delayed and more variable phenotypic progression and cellular mosaicism due to X-inactivation. In this review, we compare phenotypes of Mecp2 heterozygous female mice and male hemizygous null mouse models. Further, we discuss the complexities that arise from the many cell-type and tissue-type specific roles of MeCP2, as well as the combination of cell-autonomous and non-cell-autonomous disruptions that result from Mecp2 loss-of-function. This is of particular importance in the context of the female heterozygous brain, composed of a mixture of MeCP2+ and MeCP2- cells, the ratio of which can alter RTT phenotypes in the case of skewed X-inactivation. The goal of this review is to provide a clearer understanding of the pathophysiological differences between the mouse models, which is an essential consideration in the design of future pre-clinical studies.
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Affiliation(s)
- Mayara C Ribeiro
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, NY, United States
| | - Jessica L MacDonald
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, NY, United States.
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Xiol C, Vidal S, Pascual-Alonso A, Blasco L, Brandi N, Pacheco P, Gerotina E, O'Callaghan M, Pineda M, Armstrong J. X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients. Sci Rep 2019; 9:11983. [PMID: 31427717 PMCID: PMC6700087 DOI: 10.1038/s41598-019-48385-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 08/05/2019] [Indexed: 11/24/2022] Open
Abstract
Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern.
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Affiliation(s)
- Clara Xiol
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Silvia Vidal
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Ainhoa Pascual-Alonso
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Laura Blasco
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Núria Brandi
- Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
| | - Paola Pacheco
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Edgar Gerotina
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Mar O'Callaghan
- Neurology Service, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Mercè Pineda
- Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Judith Armstrong
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain. .,Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain. .,CIBER-ER (Biomedical Network Research Center for Rare Diseases), Instituto de Salud Carlos III, Madrid, Spain.
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Abstract
OBJECTIVE We reviewed medical records and conducted a nationwide survey to characterize the clinical features and determine the prevalence of biliary tract disease in girls and women with Rett syndrome (RTT). METHODS Sixty-two individuals with RTT and biliary tract disease were identified from the membership of Rett Syndrome Organization and patient files of the principal investigator. Medical records of 46 individuals were reviewed for presenting features, diagnostic tests, and treatment outcomes of biliary tract disease. We designed a questionnaire that probed the frequency of risk factors and treatment outcomes of biliary tract disease in RTT. The questionnaire was completed by 271 parents whose daughters met the clinical criteria for RTT and/or had MECP2 mutations and participated in the Natural History of Rett Syndrome Study. RESULTS Presenting symptoms identified by record review included abdominal pain (94%), irritability (88%), weight loss (64%), and vomiting (52%). Biliary dyskinesia, cholecystitis, and cholelithiasis were identified in 90%, 77%, and 70%, respectively, by cholescintigraphy, surgical pathology, and abdominal ultrasound. The prevalence of biliary tract disease was 4.4% (n = 12) in the RTT cohort. Risk factors included older age (P < 0.001) and a positive family history (P < 0.01). Diagnoses included cholecystitis (n = 5), biliary dyskinesia (n = 6), and cholelithiasis (n = 7). Ten individuals underwent surgery; 7 had resolution of symptoms after surgical intervention. CONCLUSIONS Biliary tract disease is not unique to RTT, but may be under-recognized because of the cognitive impairment of affected individuals. Early diagnostic evaluation and intervention may improve the health and quality of life of individuals affected with RTT and biliary tract disease.
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Abstract
Elucidating the functions of a particular gene is paramount to the understanding of how its dysfunction contributes to disease. This is especially important when the gene is implicated in multiple different disorders. One such gene is methyl-CpG-binding protein 2 (MECP2), which has been most prominently associated with the neurodevelopmental disorder Rett syndrome, as well as major neuropsychiatric disorders such as autism and schizophrenia. Being initially identified as a transcriptional regulator that modulates gene expression and subsequently also shown to be involved in other molecular events, dysfunction of the MeCP2 protein has the potential to affect many cellular processes. In this chapter, we will briefly review the functions of the MeCP2 protein and how its mutations are implicated in Rett syndrome and other neuropsychiatric disorders. We will further discuss about the mouse models that have been generated to specifically dissect the function of MeCP2 in different cell types and brain regions. It is envisioned that such thorough and targeted examination of MeCP2 functions can aid in enlightening the role that it plays in normal and dysfunctional physiological systems.
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Affiliation(s)
- Eunice W M Chin
- Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Eyleen L K Goh
- Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
- Department of Research, National Neuroscience Institute, Singapore, Singapore.
- Neuroscience Academic Clinical Programme, Singhealth Duke-NUS Academic Medical Center, Singapore, Singapore.
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Characterization of human mosaic Rett syndrome brain tissue by single-nucleus RNA sequencing. Nat Neurosci 2018; 21:1670-1679. [PMID: 30455458 PMCID: PMC6261686 DOI: 10.1038/s41593-018-0270-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 09/25/2018] [Indexed: 12/22/2022]
Abstract
In females with X-linked genetic disorders, wild-type and mutant cells coexist within brain tissue because of X-chromosome inactivation, posing challenges for interpreting the effects of X-linked mutant alleles on gene expression. We present a single-nucleus RNA sequencing approach that resolves mosaicism by using single-nucleotide polymorphisms in genes expressed in cis with the X-linked mutation to determine which nuclei express the mutant allele even when the mutant gene is not detected. This approach enables gene expression comparisons between mutant and wild-type cells within the same individual, eliminating variability introduced by comparisons to controls with different genetic backgrounds. We apply this approach to mosaic female mouse models and humans with Rett syndrome, an X-linked neurodevelopmental disorder caused by mutations in the gene encoding the methyl-DNA-binding protein MECP2, and observe that cell-type-specific DNA methylation predicts the degree of gene upregulation in MECP2-mutant neurons. This approach can be broadly applied to study gene expression in mosaic X-linked disorders.
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27
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Le Thi Thanh H, Do Thi Diem T, Duy CV, Thanh HLT, Phuong HBT, Thanh LN. Spectrum of MECP2 mutations in Vietnamese patients with RETT syndrome. BMC MEDICAL GENETICS 2018; 19:137. [PMID: 30081849 PMCID: PMC6090653 DOI: 10.1186/s12881-018-0658-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/30/2018] [Indexed: 11/29/2022]
Abstract
Background Rett syndrome (RTT) is a severe neurodevelopmental disorder in children characterized by a normal neurodevelopmental process in the first 6–18 months followed by a period of motor and vocal deterioration with stereotypic hand movements. Incidence of RTT is mostly due to de novo mutation in the MECP2 gene (methyl-CpG-binding protein 2). Methods The study assessed 27 female patients presented with classical RTT phenotype age range from 18 months to 48 months. Specialist carried out the clinical evaluation and diagnosis according to RTT diagnosis criteria. Blood samples from patients were then collected for genomic DNA extraction. We next performed MECP2 gene amplification and sequencing of the whole coding region to screen for mutations. Result MECP2 mutation was found in 20 patients (74%) including: 2 missense, 4 nonsense, 6 frameshift and 2 deletion mutation. The study identified 14 pathogenic mutations which we found 4 mutation, to our knowledge and extensive search, not priory reported in any mutation database or publication: c.1384-1385DelGT, c.1205insT, c.717delC and c.1132_1207del77. High percentage of C > T (70%) in CpG sites mutation was found. Conclusion Our result reveals a high percentage of C > T mutation in CpG hot spot, which is more prone to modification and more likely to be detected in RTT as a disorder is strictly due to de novo mutations. The study is the first to identify the mutation spectrum of MECP2 gene in Vietnamese patients and also an important step toward better diagnosis and care for RTT patients in Vietnam.
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Affiliation(s)
- Huong Le Thi Thanh
- Department of Gene Technology - Vinmec Research Institute of Stem cell and Gene Technology, 458 Minh Khai Street, Hanoi, Hai Ba Trung district, Vietnam.
| | - Trinh Do Thi Diem
- Department of Gene Technology - Vinmec Research Institute of Stem cell and Gene Technology, 458 Minh Khai Street, Hanoi, Hai Ba Trung district, Vietnam
| | - Chinh Vu Duy
- Vinmec International Hospital, 458 Minh Khai Street, Hai Ba Trung District, Hanoi, Vietnam
| | - Ha Ly Thi Thanh
- Department of Gene Technology - Vinmec Research Institute of Stem cell and Gene Technology, 458 Minh Khai Street, Hanoi, Hai Ba Trung district, Vietnam
| | - Hoa Bui Thi Phuong
- Department of Gene Technology - Vinmec Research Institute of Stem cell and Gene Technology, 458 Minh Khai Street, Hanoi, Hai Ba Trung district, Vietnam
| | - Liem Nguyen Thanh
- Department of Gene Technology - Vinmec Research Institute of Stem cell and Gene Technology, 458 Minh Khai Street, Hanoi, Hai Ba Trung district, Vietnam
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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: 25] [Impact Index Per Article: 4.2] [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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29
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Gold WA, Krishnarajy R, Ellaway C, Christodoulou J. Rett Syndrome: A Genetic Update and Clinical Review Focusing on Comorbidities. ACS Chem Neurosci 2018; 9:167-176. [PMID: 29185709 DOI: 10.1021/acschemneuro.7b00346] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Rett syndrome (RTT) is a unique neurodevelopmental disorder that primarily affects females resulting in severe cognitive and physical disabilities. Despite the commendable collective efforts of the research community to better understand the genetics and underlying biology of RTT, there is still no cure. However, in the past 50 years, since the first report of RTT, steady progress has been made in the accumulation of clinical and molecular information resulting in the identification of a number of genes associated with RTT and associated phenotypes, improved diagnostic criteria, natural history studies, curation of a number of databases capturing genotypic and phenotypic data, a number of promising clinical trials and exciting novel therapeutic options which are currently being tested in laboratory and clinical settings. This Review focuses on the current knowledge of the clinical aspects of RTT, with particular attention being paid to clinical trials and the comorbidities of the disorder as well as the genetic etiology and the recognition of new diseases genes.
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Affiliation(s)
- Wendy A Gold
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Rahul Krishnarajy
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Carolyn Ellaway
- Genetic
Metabolic Disorders Service, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - John Christodoulou
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
- Neurodevelopmental
Genomics Research Group, Murdoch Children’s Research Institute,
and Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, VIC 3010, Australia
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30
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Geens M, Chuva De Sousa Lopes SM. X chromosome inactivation in human pluripotent stem cells as a model for human development: back to the drawing board? Hum Reprod Update 2018; 23:520-532. [PMID: 28582519 DOI: 10.1093/humupd/dmx015] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 05/17/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Human pluripotent stem cells (hPSC), both embryonic and induced (hESC and hiPSC), are regarded as a valuable in vitro model for early human development. In order to fulfil this promise, it is important that these cells mimic as closely as possible the in vivo molecular events, both at the genetic and epigenetic level. One of the most important epigenetic events during early human development is X chromosome inactivation (XCI), the transcriptional silencing of one of the two X chromosomes in female cells. XCI is important for proper development and aberrant XCI has been linked to several pathologies. Recently, novel data obtained using high throughput single-cell technology during human preimplantation development have suggested that the XCI mechanism is substantially different from XCI in mouse. It has also been suggested that hPSC show higher complexity in XCI than the mouse. Here we compare the available recent data to understand whether XCI during human preimplantation can be properly recapitulated using hPSC. OBJECTIVE AND RATIONALE We will summarize what is known on the timing and mechanisms of XCI during human preimplantation development. We will compare this to the XCI patterns that are observed during hPSC derivation, culture and differentiation, and comment on the cause of the aberrant XCI patterns observed in hPSC. Finally, we will discuss the implications of the aberrant XCI patterns on the applicability of hPSC as an in vitro model for human development and as cell source for regenerative medicine. SEARCH METHODS Combinations of the following keywords were applied as search criteria in the PubMed database: X chromosome inactivation, preimplantation development, embryonic stem cells, induced pluripotent stem cells, primordial germ cells, differentiation. OUTCOMES Recent single-cell RNASeq data have shed new light on the XCI process during human preimplantation development. These indicate a gradual inactivation on both XX chromosomes, starting from Day 4 of development and followed by a random choice to inactivate one of them, instead of the mechanism in mice where imprinted XCI is followed by random XCI. We have put these new findings in perspective using previous data obtained in human (and mouse) embryos. In addition, there is an ongoing discussion whether or not hPSC lines show X chromosome reactivation upon derivation, mimicking the earliest embryonic cells, and the XCI states observed during culture of hPSC are highly variable. Recent studies have shown that hPSC rapidly progress to highly aberrant XCI patterns and that this process is probably driven by suboptimal culture conditions. Importantly, these aberrant XCI states seem to be inherited by the differentiated hPSC-progeny. WIDER IMPLICATIONS The aberrant XCI states (and epigenetic instability) observed in hPSC throw a shadow on their applicability as an in vitro model for development and disease modelling. Moreover, as the aberrant XCI states observed in hPSC seem to shift to a more malignant phenotype, this may also have important consequences for the safety aspect of using hPSC in the clinic.
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Affiliation(s)
- Mieke Geens
- Research Group Reproduction and Genetics, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Jette, Brussels, Belgium
| | - Susana M Chuva De Sousa Lopes
- Department of Anatomy and Embryology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.,Department of Reproductive Medicine, Ghent-Fertility and Stem Cell Team (G-FaST), Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
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Sbardella D, Tundo GR, Campagnolo L, Valacchi G, Orlandi A, Curatolo P, Borsellino G, D'Esposito M, Ciaccio C, Cesare SD, Pierro DD, Galasso C, Santarone ME, Hayek J, Coletta M, Marini S. Retention of Mitochondria in Mature Human Red Blood Cells as the Result of Autophagy Impairment in Rett Syndrome. Sci Rep 2017; 7:12297. [PMID: 28951555 PMCID: PMC5614985 DOI: 10.1038/s41598-017-12069-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 09/04/2017] [Indexed: 02/06/2023] Open
Abstract
Rett Syndrome (RTT), which affects approximately 1:10.000 live births, is a X-linked pervasive neuro-developmental disorder which is caused, in the vast majority of cases, by a sporadic mutation in the Methyl-CpG-binding protein-2 (MeCP2) gene. This is a transcriptional activator/repressor with presumed pleiotropic activities. The broad tissue expression of MeCP2 suggests that it may be involved in several metabolic pathways, but the molecular mechanisms which provoke the onset and progression of the syndrome are largely unknown. In this paper, we report that primary fibroblasts that have been isolated from RTT patients display a defective formation of autophagosomes under conditions of nutrient starvation and that the mature Red Blood Cells of some RTT patients retain mitochondria. Moreover, we provide evidence regarding the accumulation of the p62/SQSTM1 protein and ubiquitin-aggregated structures in the cerebellum of Mecp2 knockout mouse model (Mecp2−/y) during transition from the non-symptomatic to the symptomatic stage of the disease. Hence, we propose that a defective autophagy could be involved in the RTT clinical phenotype, which introduces new molecular perspectives in the pathogenesis of the syndrome.
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Affiliation(s)
- Diego Sbardella
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Grazia Raffaella Tundo
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Luisa Campagnolo
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Giuseppe Valacchi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.,Plant for Human Health Institute, North Carolina State University, Kannapolis, NC, USA
| | - Augusto Orlandi
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Paolo Curatolo
- Department of Medicine of Systems, University of Tor Vergata, Rome, Italy
| | | | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "A.Buzzati Traverso", Naples, Italy.,IRCCS Neuromed, Pozzuoli, (Is), Italy
| | - Chiara Ciaccio
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Silvia Di Cesare
- University Department of Pediatrics, Bambino Gesù Children's Hospital, University of Rome Tor Vergata, Rome, Italy
| | - Donato Di Pierro
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Cinzia Galasso
- Department of Medicine of Systems, University of Tor Vergata, Rome, Italy
| | | | - Joussef Hayek
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese (AOUS), Siena, Italy
| | - Massimiliano Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Stefano Marini
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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Differential X Chromosome Inactivation Patterns during the Propagation of Human Induced Pluripotent Stem Cells. Keio J Med 2017; 66:1-8. [PMID: 28111378 DOI: 10.2302/kjm.2016-0015-oa] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Human induced pluripotent stem cells (hiPSCs) represent a potentially useful tool for studying the molecular mechanisms of disease thanks to their ability to generate patient-specific hiPSC clones. However, previous studies have reported that DNA methylation profiles, including those for imprinted genes, may change during passaging of hiPSCs. This is particularly problematic for hiPSC models of X-linked disease, because unstable X chromosome inactivation status may affect the detection of phenotypes. In the present study, we examined the epigenetic status of hiPSCs derived from patients with Rett syndrome, an X-linked disease, during long-term culture. To analyze X chromosome inactivation, we used a methylation-specific polymerase chain reaction (MSP) to assay the human androgen receptor locus (HUMARA). We found that single cell-derived hiPSC clones exhibit various states of X chromosome inactivation immediately after clonal isolation, even when established simultaneously from a single donor. X chromosome inactivation states remain variable in hiPSC clones at early passages, and this variability may affect cellular phenotypes characteristic of X-linked diseases. Careful evaluation of X chromosome inactivation in hiPSC clones, particularly in early passages, by methods such as HUMARA-MSP, is therefore important when using patient-specific hiPSCs to model X-linked disease.
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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: 132] [Impact Index Per Article: 16.5] [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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Rangasamy S, Olfers S, Gerald B, Hilbert A, Svejda S, Narayanan V. Reduced neuronal size and mTOR pathway activity in the Mecp2 A140V Rett syndrome mouse model. F1000Res 2016; 5:2269. [PMID: 27781091 PMCID: PMC5040159 DOI: 10.12688/f1000research.8156.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/01/2016] [Indexed: 12/22/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutation in the X-linked
MECP2 gene, encoding methyl-CpG-binding protein 2. We have created a mouse model (
Mecp2 A140V “knock-in” mutant) expressing the recurrent human
MECP2 A140V mutation linked to an X-linked mental retardation/Rett syndrome phenotype. Morphological analyses focused on quantifying soma and nucleus size were performed on primary hippocampus and cerebellum granule neuron (CGN) cultures from mutant (
Mecp2A140V/y) and wild type (
Mecp2+/y) male mice. Cultured hippocampus and cerebellar granule neurons from mutant animals were significantly smaller than neurons from wild type animals. We also examined soma size in hippocampus neurons from individual female transgenic mice that express both a mutant (maternal allele) and a wild type
Mecp2 gene linked to an eGFP transgene (paternal allele). In cultures from such doubly heterozygous female mice, the size of neurons expressing the mutant (A140V) allele also showed a significant reduction compared to neurons expressing wild type MeCP2, supporting a cell-autonomous role for MeCP2 in neuronal development. IGF-1 (insulin growth factor-1) treatment of neuronal cells from
Mecp2 mutant mice rescued the soma size phenotype. We also found that
Mecp2 mutation leads to down-regulation of the mTOR signaling pathway, known to be involved in neuronal size regulation. Our results suggest that i) reduced neuronal size is an important
in vitro cellular phenotype of
Mecp2 mutation in mice, and ii) MeCP2 might play a critical role in the maintenance of neuronal structure by modulation of the mTOR pathway. The definition of a quantifiable cellular phenotype supports using neuronal size as a biomarker in the development of a high-throughput,
in vitro assay to screen for compounds that rescue small neuronal phenotype (“phenotypic assay”).
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Affiliation(s)
- Sampathkumar Rangasamy
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, USA; Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, USA
| | - Shannon Olfers
- Barrow Neurological Institute, St.Joseph's Hospital and Medical Center, Phoenix, USA
| | - Brittany Gerald
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, USA; Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, USA; School of Life Sciences, Arizona State University, Tempe, USA
| | - Alex Hilbert
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, USA; School of Life Sciences, Arizona State University, Tempe, USA
| | - Sean Svejda
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, USA; Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, USA
| | - Vinodh Narayanan
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, USA; Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, USA; Barrow Neurological Institute, St.Joseph's Hospital and Medical Center, Phoenix, USA; School of Life Sciences, Arizona State University, Tempe, USA
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35
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Williams AA, Mehler VJ, Mueller C, Vonhoff F, White R, Duch C. Apoptotic Activity of MeCP2 Is Enhanced by C-Terminal Truncating Mutations. PLoS One 2016; 11:e0159632. [PMID: 27442528 PMCID: PMC4956225 DOI: 10.1371/journal.pone.0159632] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 07/05/2016] [Indexed: 11/22/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a widely abundant, multifunctional protein most highly expressed in post-mitotic neurons. Mutations causing Rett syndrome and related neurodevelopmental disorders have been identified along the entire MECP2 locus, but symptoms vary depending on mutation type and location. C-terminal mutations are prevalent, but little is known about the function of the MeCP2 C-terminus. We employ the genetic efficiency of Drosophila to provide evidence that expression of p.Arg294* (more commonly identified as R294X), a human MECP2 E2 mutant allele causing truncation of the C-terminal domains, promotes apoptosis of identified neurons in vivo. We confirm this novel finding in HEK293T cells and then use Drosophila to map the region critical for neuronal apoptosis to a small sequence at the end of the C-terminal domain. In vitro studies in mammalian systems previously indicated a role of the MeCP2 E2 isoform in apoptosis, which is facilitated by phosphorylation at serine 80 (S80) and decreased by interactions with the forkhead protein FoxG1. We confirm the roles of S80 phosphorylation and forkhead domain transcription factors in affecting MeCP2-induced apoptosis in Drosophila in vivo, thus indicating mechanistic conservation between flies and mammalian cells. Our findings are consistent with a model in which C- and N-terminal interactions are required for healthy function of MeCP2.
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Affiliation(s)
- Alison A. Williams
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Institute of Zoology- Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Vera J. Mehler
- Institute of Zoology- Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | - Fernando Vonhoff
- Molecular, Cellular, and Developmental Biology Department, Yale University, New Haven, Connecticut, United States of America
| | - Robin White
- Institute of Physiology, University Medical Center, Mainz, Germany
| | - Carsten Duch
- Institute of Zoology- Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
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Neupane M, Clark AP, Landini S, Birkbak NJ, Eklund AC, Lim E, Culhane AC, Barry WT, Schumacher SE, Beroukhim R, Szallasi Z, Vidal M, Hill DE, Silver DP. MECP2 Is a Frequently Amplified Oncogene with a Novel Epigenetic Mechanism That Mimics the Role of Activated RAS in Malignancy. Cancer Discov 2015; 6:45-58. [PMID: 26546296 DOI: 10.1158/2159-8290.cd-15-0341] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 11/04/2015] [Indexed: 02/07/2023]
Abstract
UNLABELLED An unbiased genome-scale screen for unmutated genes that drive cancer growth when overexpressed identified methyl cytosine-guanine dinucleotide (CpG) binding protein 2 (MECP2) as a novel oncogene. MECP2 resides in a region of the X-chromosome that is significantly amplified across 18% of cancers, and many cancer cell lines have amplified, overexpressed MECP2 and are dependent on MECP2 expression for growth. MECP2 copy-number gain and RAS family member alterations are mutually exclusive in several cancer types. The MECP2 splicing isoforms activate the major growth factor pathways targeted by activated RAS, the MAPK and PI3K pathways. MECP2 rescued the growth of a KRAS(G12C)-addicted cell line after KRAS downregulation, and activated KRAS rescues the growth of an MECP2-addicted cell line after MECP2 downregulation. MECP2 binding to the epigenetic modification 5-hydroxymethylcytosine is required for efficient transformation. These observations suggest that MECP2 is a commonly amplified oncogene with an unusual epigenetic mode of action. SIGNIFICANCE MECP2 is a commonly amplified oncogene in human malignancies with a unique epigenetic mechanism of action. Cancer Discov; 6(1); 45-58. ©2015 AACR.This article is highlighted in the In This Issue feature, p. 1.
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Affiliation(s)
- Manish Neupane
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Allison P Clark
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Serena Landini
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Nicolai J Birkbak
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Aron C Eklund
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Elgene Lim
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Aedin C Culhane
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, and Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - William T Barry
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, and Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Steven E Schumacher
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Broad Institute of Harvard and MIT, Cambridge, Massachusetts
| | - Rameen Beroukhim
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts. Broad Institute of Harvard and MIT, Cambridge, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Zoltan Szallasi
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark. Children's Hospital Informatics Program at the Harvard-MIT Division of Health Sciences and Technology, and Harvard Medical School, Boston, Massachusetts
| | - Marc Vidal
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - David E Hill
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Daniel P Silver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts. Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, Massachusetts.
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Over-expression of XIST, the Master Gene for X Chromosome Inactivation, in Females With Major Affective Disorders. EBioMedicine 2015; 2:909-18. [PMID: 26425698 PMCID: PMC4563114 DOI: 10.1016/j.ebiom.2015.06.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 11/23/2022] Open
Abstract
Background Psychiatric disorders are common mental disorders without a pathological biomarker. Classic genetic studies found that an extra X chromosome frequently causes psychiatric symptoms in patients with either Klinefelter syndrome (XXY) or Triple X syndrome (XXX). Over-dosage of some X-linked escapee genes was suggested to cause psychiatric disorders. However, relevance of these rare genetic diseases to the pathogenesis of psychiatric disorders in the general population of psychiatric patients is unknown. Methods XIST and several X-linked genes were studied in 36 lymphoblastoid cell lines from healthy females and 60 lymphoblastoid cell lines from female patients with either bipolar disorder or recurrent major depression. XIST and KDM5C expression was also quantified in 48 RNA samples from postmortem human brains of healthy female controls and female psychiatric patients. Findings We found that the XIST gene, a master in control of X chromosome inactivation (XCI), is significantly over-expressed (p = 1 × 10− 7, corrected after multiple comparisons) in the lymphoblastoid cells of female patients with either bipolar disorder or major depression. The X-linked escapee gene KDM5C also displays significant up-regulation (p = 5.3 × 10− 7, corrected after multiple comparisons) in the patients' cells. Expression of XIST and KDM5C is highly correlated (Pearson's coefficient, r = 0.78, p = 1.3 × 10− 13). Studies on human postmortem brains supported over-expression of the XIST gene in female psychiatric patients. Interpretations We propose that over-expression of XIST may cause or result from subtle alteration of XCI, which up-regulates the expression of some X-linked escapee genes including KDM5C. Over-expression of X-linked genes could be a common mechanism for the development of psychiatric disorders between patients with those rare genetic diseases and the general population of female psychiatric patients with XIST over-expression. Our studies suggest that XIST and KDM5C expression could be used as a biological marker for diagnosis of psychiatric disorders in a significantly large subset of female patients. Research in context Due to lack of biological markers, diagnosis and treatment of psychiatric disorders are subjective. There is utmost urgency to identify biomarkers for clinics, research, and drug development. We found that XIST and KDM5C gene expression may be used as a biological marker for diagnosis of major affective disorders in a significantly large subset of female patients from the general population. Our studies show that over-expression of XIST and some X-linked escapee genes may be a common mechanism for development of psychiatric disorders between the patients with rare genetic diseases (XXY or XXX) and the general population of female psychiatric patients. XIST and KDM5C genes are over-expressed in a large subset of female patients with major affective disorders. Over-expression of XIST and KDM5C genes could be used as a biomarker for diagnosis of individual patients. Over-expression of XIST and X-linked escapee genes including KDM5C may cause major affective disorders.
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Andoh-Noda T, Akamatsu W, Miyake K, Matsumoto T, Yamaguchi R, Sanosaka T, Okada Y, Kobayashi T, Ohyama M, Nakashima K, Kurosawa H, Kubota T, Okano H. Differentiation of multipotent neural stem cells derived from Rett syndrome patients is biased toward the astrocytic lineage. Mol Brain 2015; 8:31. [PMID: 26012557 PMCID: PMC4446051 DOI: 10.1186/s13041-015-0121-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/30/2015] [Indexed: 12/23/2022] Open
Abstract
Background Rett syndrome (RTT) is one of the most prevalent neurodevelopmental disorders in females, caused by de novo mutations in the X-linked methyl CpG-binding protein 2 gene, MECP2. Although abnormal regulation of neuronal genes due to mutant MeCP2 is thought to induce autistic behavior and impaired development in RTT patients, precise cellular mechanisms underlying the aberrant neural progression remain unclear. Results Two sets of isogenic pairs of either wild-type or mutant MECP2-expressing human induced pluripotent stem cell (hiPSC) lines were generated from a single pair of 10-year-old RTT-monozygotic (MZ) female twins. Mutant MeCP2-expressing hiPSC lines did not express detectable MeCP2 protein during any stage of differentiation. The lack of MeCP2 reflected altered gene expression patterns in differentiated neural cells rather than in undifferentiated hiPSCs, as assessed by microarray analysis. Furthermore, MeCP2 deficiency in the neural cell lineage increased astrocyte-specific differentiation from multipotent neural stem cells. Additionally, chromatin immunoprecipitation (ChIP) and bisulfite sequencing assays indicated that anomalous glial fibrillary acidic protein gene (GFAP) expression in the MeCP2-negative, differentiated neural cells resulted from the absence of MeCP2 binding to the GFAP gene. Conclusions An isogenic RTT-hiPSC model demonstrated that MeCP2 participates in the differentiation of neural cells. Moreover, MeCP2 deficiency triggers perturbation of astrocytic gene expression, yielding accelerated astrocyte formation from RTT-hiPSC-derived neural stem cells. These findings are likely to shed new light on astrocytic abnormalities in RTT, and suggest that astrocytes, which are required for neuronal homeostasis and function, might be a new target of RTT therapy. Electronic supplementary material The online version of this article (doi:10.1186/s13041-015-0121-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomoko Andoh-Noda
- Division of Medicine and Engineering Science, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-4-37 Takeda, Yamanashi, Kofu, 400-8510, Japan. .,Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Wado Akamatsu
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan. .,Center for Genomic and Regenerative Medicine, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Kunio Miyake
- Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
| | - Takuya Matsumoto
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Ryo Yamaguchi
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan. .,Sumitomo Dainipponn Pharma Co. Ltd., Osaka, Osaka, 541-0045, Japan.
| | - Tsukasa Sanosaka
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Yohei Okada
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan. .,Department of Neurology,School of Meidicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan.
| | - Tetsuro Kobayashi
- Department of Dermatology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Manabu Ohyama
- Department of Dermatology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Kinichi Nakashima
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Hiroshi Kurosawa
- Division of Medicine and Engineering Science, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-4-37 Takeda, Yamanashi, Kofu, 400-8510, Japan.
| | - Takeo Kubota
- Department of Epigenetic Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi,Shinjuku-ku, Tokyo, 160-8582, Japan.
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Co-occurrence of Dystonic and Dyskinetic Tongue Movements with Oral Apraxia in Post-regression Dysphagia in Classical Rett Syndrome Years of Life 1 Through 5. Dysphagia 2014; 30:128-38. [DOI: 10.1007/s00455-014-9587-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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Abstract
The recent descriptions of widespread random monoallelic expression (RMAE) of genes distributed throughout the autosomal genome indicate that there are more genes subject to RMAE on autosomes than the number of genes on the X chromosome where X-inactivation dictates RMAE of X-linked genes. Several of the autosomal genes that undergo RMAE have independently been implicated in human Mendelian disorders. Thus, parsing the relationship between allele-specific expression of these genes and disease is of interest. Mutations in the human forkhead box P2 gene, FOXP2, cause developmental verbal dyspraxia with profound speech and language deficits. Here, we show that the human FOXP2 gene undergoes RMAE. Studying an individual with developmental verbal dyspraxia, we identify a deletion 3 Mb away from the FOXP2 gene, which impacts FOXP2 gene expression in cis. Together these data suggest the intriguing possibility that RMAE impacts the haploinsufficiency phenotypes observed for FOXP2 mutations.
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Fabio RA, Colombo B, Russo S, Cogliati F, Masciadri M, Foglia S, Antonietti A, Tavian D. Recent insights into genotype-phenotype relationships in patients with Rett syndrome using a fine grain scale. RESEARCH IN DEVELOPMENTAL DISABILITIES 2014; 35:2976-2986. [PMID: 25124696 DOI: 10.1016/j.ridd.2014.07.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 06/03/2023]
Abstract
Mutations in MECP2 gene cause Rett syndrome (RTT), a neurodevelopmental disorder affecting around 1 in 10,000 female births. The clinical picture of RTT appears quite heterogeneous for each single feature. Mutations in MECP2 gene have been associated with the onset of RTT. The most known gene function consists of transcriptional repression of specific target genes, mainly by the binding of its methyl binding domain (MBD) to methylated CpG nucleotides and recruiting co-repressors and histone deacetylase binding to DNA by its transcription repressor domain (TRD). This study aimed at evaluating a cohort of 114 Rett syndrome (RTT) patients with a detailed scale measuring the different kinds of impairments produced by the syndrome. The sample included relatively large subsets of the most frequent mutations, so that genotype-phenotype correlations could be tested. Results revealed that frequent missense mutations showed a specific profile in different areas of impairment. The R306C mutation, considered as producing mild impairment, was associated to a moderate phenotype in which behavioural characteristics were mainly affected. A notable difference emerged by comparing mutations truncating the protein before and after the nuclear localization signal; such a difference concerned prevalently the motor-functional and autonomy skills of the patients, affecting the management of everyday activities.
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Affiliation(s)
- Rosa Angela Fabio
- Department of Cognitive Science, Education and Cultural Studies, University of Messina, via Concezione 8, 98122 Messina, Italy.
| | - Barbara Colombo
- Department of Psychology, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milano, Italy
| | - Silvia Russo
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, via Ariosto 13, 20145 Milano, Italy
| | - Francesca Cogliati
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, via Ariosto 13, 20145 Milano, Italy
| | - Maura Masciadri
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, via Ariosto 13, 20145 Milano, Italy
| | - Silvia Foglia
- Department of Psychology, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milano, Italy
| | - Alessandro Antonietti
- Department of Psychology, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milano, Italy
| | - Daniela Tavian
- Department of Psychology, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milano, Italy; Laboratory of Cellular Biochemistry and Molecular Biology-CRIBENS, Catholic University of the Sacred Heart, Piazza Buonarroti 30, 20145 Milano, Italy
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Abstract
Epigenetic control of gene expression programs is essential for normal organismal development and cellular function. Abrogation of epigenetic regulation is seen in many human diseases, including cancer and neuropsychiatric disorders, where it can affect disease etiology and progression. Abnormal epigenetic profiles can serve as biomarkers of disease states and predictors of disease outcomes. Therefore, epigenetics is a key area of clinical investigation in diagnosis, prognosis, and treatment. In this review, we give an overarching view of epigenetic mechanisms of human disease. Genetic mutations in genes that encode chromatin regulators can cause monogenic disease or are incriminated in polygenic, multifactorial diseases. Environmental stresses can also impact directly on chromatin regulation, and these changes can increase the risk of, or directly cause, disease. Finally, emerging evidence suggests that exposure to environmental stresses in older generations may predispose subsequent generations to disease in a manner that involves the transgenerational inheritance of epigenetic information.
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Affiliation(s)
- Emily Brookes
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
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Motil KJ, Barrish JO, Neul JL, Glaze DG. Low bone mineral mass is associated with decreased bone formation and diet in girls with Rett syndrome. J Pediatr Gastroenterol Nutr 2014; 59:386-92. [PMID: 25144778 PMCID: PMC4144049 DOI: 10.1097/mpg.0000000000000440] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE The aim of the present study was to characterize biomarkers of bone turnover and their relation with bone mineral mass in a cross-sectional cohort of girls with Rett syndrome (RTT) and to examine the role of dietary, biochemical, hormonal, and inflammatory factors on bone mineral mass and bone biomarkers in this disorder. METHODS Total body bone mineral content (BMC) and bone mineral density (BMD) were determined by dual-energy x-ray absorptiometry. Dietary nutrient intakes were determined from 3-day food records. Biomarkers of bone turnover, bone metabolites, vitamin D metabolites, hormones, and inflammatory markers were measured by standard clinical laboratory methods. RESULTS Serum osteocalcin, bone alkaline phosphatase, and C-telopeptide showed significant inverse relations with age in the RTT cohort. Mean osteocalcin concentrations were significantly lower and mean bone alkaline phosphatase concentrations were significantly higher for individual age groups in the RTT cohort than mean values for their respective age ranges in the reference population. Significant inverse associations were identified between urinary calcium losses, expressed as calcium:creatinine ratios, and total body BMC and BMD z scores. Dietary protein, calcium, and phosphorus intakes, expressed as a proportion of Dietary Reference Intakes for age and sex, showed significant positive associations with total body BMD z scores. CONCLUSIONS The present study suggests decreased bone formation instead of increased bone resorption may explain in part the deficits in bone mineral mass in RTT and that attention to the adequacy of dietary protein, calcium, and phosphorus intakes may offer an opportunity to improve bone health in RTT.
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Affiliation(s)
- Kathleen J. Motil
- USDA/ARS Children's Nutrition Research Center, Houston, TX 77030
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
| | - Judy O. Barrish
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
- The Blue Bird Circle Rett Center, Houston, TX 77030
| | - Jeffrey L. Neul
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
- The Blue Bird Circle Rett Center, Houston, TX 77030
| | - Daniel G. Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030
- The Blue Bird Circle Rett Center, Houston, TX 77030
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Functional recovery with recombinant human IGF1 treatment in a mouse model of Rett Syndrome. Proc Natl Acad Sci U S A 2014; 111:9941-6. [PMID: 24958891 DOI: 10.1073/pnas.1311685111] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Rett Syndrome is a neurodevelopmental disorder that arises from mutations in the X-linked gene methyl-CpG binding protein 2 (MeCP2). MeCP2 has a large number of targets and a wide range of functions, suggesting the hypothesis that functional signaling mechanisms upstream of synaptic and circuit maturation may contribute to our understanding of the disorder and provide insight into potential treatment. Here, we show that insulin-like growth factor-1 (IGF1) levels are reduced in young male Mecp2-null (Mecp2(-/y)) mice, and systemic treatment with recombinant human IGF1 (rhIGF1) improves lifespan, locomotor activity, heart rate, respiration patterns, and social and anxiety behavior. Furthermore, Mecp2-null mice treated with rhIGF1 show increased synaptic and activated signaling pathway proteins, enhanced cortical excitatory synaptic transmission, and restored dendritic spine densities. IGF1 levels are also reduced in older, fully symptomatic heterozygous (Mecp2(-/+)) female mice, and short-term treatment with rhIGF1 in these animals improves respiratory patterns, reduces anxiety levels, and increases exploratory behavior. In addition, rhIGF1 treatment normalizes abnormally prolonged plasticity in visual cortex circuits of adult Mecp2(-/+) female mice. Our results provide characterization of the phenotypic development of Rett Syndrome in a mouse model at the molecular, circuit, and organismal levels and demonstrate a mechanism-based therapeutic role for rhIGF1 in treating Rett Syndrome.
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Abstract
The role of epigenetics in human disease has become an area of increased research interest. Collaborative efforts from scientists and clinicians have led to a better understanding of the molecular mechanisms by which epigenetic regulation is involved in the pathogenesis of many human diseases. Several neurological and non-neurological disorders are associated with mutations in genes that encode for epigenetic factors. One of the most studied proteins that impacts human disease and is associated with deregulation of epigenetic processes is Methyl CpG binding protein 2 (MeCP2). MeCP2 is an epigenetic regulator that modulates gene expression by translating epigenetic DNA methylation marks into appropriate cellular responses. In order to highlight the importance of epigenetics to development and disease, we will discuss how MeCP2 emerges as a key epigenetic player in human neurodevelopmental, neurological, and non-neurological disorders. We will review our current knowledge on MeCP2-related diseases, including Rett Syndrome, Angelman Syndrome, Fetal Alcohol Spectrum Disorder, Hirschsprung disease, and Cancer. Additionally, we will briefly discuss about the existing MeCP2 animal models that have been generated for a better understanding of how MeCP2 impacts certain human diseases.
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Affiliation(s)
| | - Mojgan Rastegar
- Author to whom correspondence should be addressed; ; Tel.: +204-272-3108; Fax: +204-789-3900
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46
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Lotan M, Reves-Siesel R, Eliav-Shalev RS, Merrick J. Osteoporosis in Rett syndrome: a case study presenting a novel management intervention for severe osteoporosis. Osteoporos Int 2013; 24:3059-63. [PMID: 23828127 DOI: 10.1007/s00198-013-2423-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 05/31/2013] [Indexed: 10/26/2022]
Abstract
The present article describes a successful novel therapeutic intervention with Aredia with one child with Rett syndrome, after suffering from six pathological fractures within less than 3 years due to severe osteoporosis. Since the initiation of the treatment (3 years ago), the child has not suffered any fractures. Patients with chronic diseases and those with disabilities or on anticonvulsant medications are at risk for low bone density and possibly for the resultant pathologic fractures that define osteoporosis in children. Individuals with Rett syndrome (RS) have been shown to have low bone mineral density (or osteopenia) at a young age. If osteoporosis occurs in a girl with RS, it can inflict pain and seriously impair the child's mobility and quality of life. The present article describes a case study of a child with RS (showing an average of 1.75 fractures annually for the 4 years preceding the treatment) before and after a treatment with Aredia. Patient received 30 mg/day for 3 days on a once every 3-month cycle. There was a 45 % improvement in bone mass density (BMD) values from pre-post-intervention. The child had no fractures in the 3 years posttreatment. This finding is significant (p < 0.03). The BMD Z-scores of the child showed severe osteoporosis (Z-score of -3.8) at pre-intervention and are elevated to osteopenia levels (Z-score of -1.3) at post-intervention measurements. All measurements suggest that the treatment successfully reversed the osteoporotic process and prevented further fractures. This change caused great relief to the child and her family and an improvement in their quality of life. The findings support the ability (in one case) to reverse the progression of osteoporosis in individuals with Rett syndrome showing severe osteoporosis with multiple fractures.
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Affiliation(s)
- M Lotan
- Israeli Rett Center, National Rett Syndrome Evaluation Team, Chaim Sheba Medical Center, Tel HaShomer, Ramat Gan, Israel,
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Kao FC, Su SH, Carlson GC, Liao W. MeCP2-mediated alterations of striatal features accompany psychomotor deficits in a mouse model of Rett syndrome. Brain Struct Funct 2013; 220:419-34. [PMID: 24218106 DOI: 10.1007/s00429-013-0664-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/15/2013] [Indexed: 12/15/2022]
Abstract
Rett Syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the methyl-CpG-binding protein 2 (MECP2) gene. Affected individuals develop motor deficits including stereotypic hand movements, impaired motor learning and difficulties with movement. To understand the neural mechanisms of motor deficits in RTT, we characterized the molecular and cellular phenotypes in the striatum, the major input nucleus of the basal ganglia that controls psychomotor function, in mice carrying a null allele of Mecp2. These mice showed significant hypoactivity associated with impaired motor coordination and motor skill learning. We found that dopamine content was significantly reduced in the striatum of Mecp2 null mice. Reduced dopamine was accompanied by down-regulation of tyrosine hydroxylase and up-regulation of dopamine D2 receptors, particularly in the rostral striatum. We also observed that loss of MeCP2 induced compartment-specific alterations in the striatum, including reduced expression of μ-opioid receptors in the striosomes and increased number of calbindin-positive neurons in the striatal matrix. The total number of parvalbumin-positive interneurons and their dendritic arborization were also significantly increased in the striatum of Mecp2 null mice. Together, our findings support that MeCP2 regulates a unique set of genes critical for modulating motor output of the striatum, and that aberrant structure and function of the striatum due to MeCP2 deficiency may underlie the motor deficits in RTT.
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Affiliation(s)
- Fang-Chi Kao
- Institute of Neuroscience, National Cheng-Chi University, 64, Sec. 2, Chi-Nan Road, Wen-Shan District, Taipei, 11605, Taiwan
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Leonard H, Ravikumara M, Baikie G, Naseem N, Ellaway C, Percy A, Abraham S, Geerts S, Lane J, Jones M, Bathgate K, Downs J. Assessment and management of nutrition and growth in Rett syndrome. J Pediatr Gastroenterol Nutr 2013; 57:451-60. [PMID: 24084372 PMCID: PMC3906202 DOI: 10.1097/mpg.0b013e31829e0b65] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES We developed recommendations for the clinical management of poor growth and weight gain in Rett syndrome through evidence review and the consensus of an expert panel of clinicians. METHODS Initial draft recommendations were created based upon literature review and 34 open-ended questions in which the literature was lacking. Statements and questions were made available to an international, multidisciplinary panel of clinicians in an online format and a Microsoft Word-formatted version of the draft via e-mail. Input was sought using a 2-stage modified Delphi process to reach consensus. Items included clinical assessment of growth, anthropometry, feeding difficulties and management to increase energy intake, decrease feeding difficulties, and consideration of gastrostomy. RESULTS Agreement was achieved on 101 of 112 statements. A comprehensive approach to the management of poor growth in Rett syndrome is recommended that takes into account factors such as feeding difficulties and nutritional needs. A body mass index of approximately the 25th centile can be considered as a reasonable target in clinical practice. Gastrostomy is indicated for extremely poor growth, if there is risk of aspiration and if feeding times are prolonged. CONCLUSIONS These evidence- and consensus-based recommendations have the potential to improve care of nutrition and growth in a rare condition and stimulate research to improve the present limited evidence base.
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Affiliation(s)
- Helen Leonard
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
| | - Madhur Ravikumara
- Department of Gastroenterology, Princess Margaret Hospital for Children, Perth, Western Australia
| | - Gordon Baikie
- Department of Developmental Medicine, Royal Children’s Hospital, Murdoch Children’s Research Institute, Melbourne, Australia
| | - Nusrat Naseem
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
| | - Carolyn Ellaway
- Western Sydney Genetics Program, The Children’s Hospital at Westmead, Discipline of Paediatrics and Genetic Medicine, University of Sydney, Australia
| | - Alan Percy
- Civitan International Research Centre, University of Alabama, Birmingham, Alabama, USA
| | - Suzanne Abraham
- Department of Otolaryngology Head Neck Surgery and Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, USA
| | - Suzanne Geerts
- Civitan International Research Centre, University of Alabama, Birmingham, Alabama, USA
| | - Jane Lane
- Civitan International Research Centre, University of Alabama, Birmingham, Alabama, USA
| | - Mary Jones
- Katie's Clinic for Rett Syndrome, Children's Hospital & Research Center, Oakland, California, USA
| | - Katherine Bathgate
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
- School of Public Health and Curtin Health Innovation Research Institute, Perth, Western Australia
| | - Jenny Downs
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Western Australia
- School of Physiotherapy and Curtin Health Innovation Research Institute, Perth, Western Australia
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Savova V, Vigneau S, Gimelbrant AA. Autosomal monoallelic expression: genetics of epigenetic diversity? Curr Opin Genet Dev 2013; 23:642-8. [PMID: 24075575 DOI: 10.1016/j.gde.2013.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 11/17/2022]
Abstract
In mammals, relative expression of the two parental alleles of many genes is controlled by one of three major epigenetic phenomena: X chromosome inactivation, imprinting, and mitotically stable autosomal monoallelic expression (MAE). MAE affects a large fraction of human autosomal genes and introduces enormous epigenetic heterogeneity in otherwise similar cell populations. Despite its prevalence, many functional and mechanistic aspects of MAE biology remain unknown. Several lines of evidence imply that MAE establishment and maintenance are controlled by a variety of genetic elements. Based on known genomic features regulating X-inactivation and imprinting, we outline likely features of MAE-controlling elements. We also assess implications of MAE for genotype-phenotype relationship, with a focus on haploinsufficiency.
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Affiliation(s)
- Virginia Savova
- Department of Cancer Biology, Dana-Farber Cancer Institute, Department of Genetics, Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215, United States
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Ramirez JM, Ward CS, Neul JL. Breathing challenges in Rett syndrome: lessons learned from humans and animal models. Respir Physiol Neurobiol 2013; 189:280-7. [PMID: 23816600 DOI: 10.1016/j.resp.2013.06.022] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/21/2013] [Accepted: 06/24/2013] [Indexed: 01/17/2023]
Abstract
Breathing disturbances are a major challenge in Rett Syndrome (RTT). These disturbances are more pronounced during wakefulness; but irregular breathing occurs also during sleep. During the day patients can exhibit alternating bouts of hypoventilation and irregular hyperventilation. But there is significant individual variability in severity, onset, duration and type of breathing disturbances. Research in mouse models of RTT suggests that different areas in the ventrolateral medulla and pons give rise to different aspects of this breathing disorder. Pre-clinical experiments in mouse models that target different neuromodulatory and neurotransmitter receptors and MeCP2 function within glia cells can partly reverse breathing abnormalities. The success in animal models raises optimism that one day it will be possible to control or potentially cure the devastating symptoms also in human patients with RTT.
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Affiliation(s)
- Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Neurological Surgery, University of Washington, Seattle, WA 98101, USA.
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