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Hu C, Li H, Li J, Luo X, Hao Y. Microglia: Synaptic modulator in autism spectrum disorder. Front Psychiatry 2022; 13:958661. [PMID: 36465285 PMCID: PMC9714329 DOI: 10.3389/fpsyt.2022.958661] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/28/2022] [Indexed: 11/18/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by variable impairment of social communication and repetitive behaviors, highly restricted interests, and/or sensory behaviors beginning early in life. Many individuals with ASD have dysfunction of microglia, which may be closely related to neuroinflammation, making microglia play an important role in the pathogenesis of ASD. Mounting evidence indicates that microglia, the resident immune cells of the brain, are required for proper brain function, especially in the maintenance of neuronal circuitry and control of behavior. Dysfunction of microglia will ultimately affect the neural function in a variety of ways, including the formation of synapses and alteration of excitatory-inhibitory balance. In this review, we provide an overview of how microglia actively interact with neurons in physiological conditions and modulate the fate and functions of synapses. We put a spotlight on the multi-dimensional neurodevelopmental roles of microglia, especially in the essential influence of synapses, and discuss how microglia are currently thought to influence ASD progression.
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Affiliation(s)
- Cong Hu
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heli Li
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinhui Li
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoping Luo
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Hao
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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2
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Matson JL, Dempsey T, Wilkins J. Rett syndrome in adults with severe intellectual disability: Exploration of behavioral characteristics. Eur Psychiatry 2020; 23:460-5. [DOI: 10.1016/j.eurpsy.2007.11.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2007] [Revised: 11/03/2007] [Accepted: 11/05/2007] [Indexed: 10/22/2022] Open
Abstract
AbstractRett syndrome is a genetically linked form of autism spectrum disorder (ASD) accompanied by intellectual disability (ID). The disorder is also characterized by cardiorespiratory dysregulation, disturbance in muscle tone, reduced brain growth and scoliosis. Over 300 studies have been published on the disorder, most of which has focused on identification of causative factors, which appears to be the result of mutations of gene MECP2. Rarely have adults with Rett syndrome been studied, and behavioral characteristics in these individuals are largely unknown. The present study aimed to extend what little is known about behavioral characteristics of Rett syndrome in adults, with particular emphasis on social, communicative, and adaptive behavior. Rett syndrome adults with severe ID were matched to autistic adults with ID and ID only controls. The implications of these data for more fully describing and diagnosing the condition in adults are discussed.
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3
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Müller M. Disturbed redox homeostasis and oxidative stress: Potential players in the developmental regression in Rett syndrome. Neurosci Biobehav Rev 2019; 98:154-163. [PMID: 30639673 DOI: 10.1016/j.neubiorev.2018.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/30/2018] [Accepted: 12/06/2018] [Indexed: 12/16/2022]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder affecting mostly girls. A seemingly normal initial development is followed by developmental stagnation and regression, leading to severe mental impairment with autistic features, motor dysfunction, irregular breathing and epilepsy. Currently, a cure does not exist. Due to the close association of RTT with mitochondrial alterations, cellular redox-impairment and oxidative stress, compounds stabilizing mitochondrial function, cellular redox-homeostasis, and oxidant detoxification are increasingly considered as treatment concepts. Indeed, antioxidants and free-radical scavengers ameliorate certain aspects of the complex and severe clinical presentation of RTT. To further evaluate these strategies, reliable biosensors are needed to quantify redox-conditions in brain and peripheral organs of mouse models or in patient-derived cells. Genetically-encoded redox-sensors meet these requirements. Expressed in transgenic mouse-models such as our unique Rett-redox indicator mice, they will report for any cell type desired the severity of oxidant stress throughout the various disease stages of RTT. Furthermore, these sensors will be crucial to evaluate in vitro and in vivo the outcome of mitochondria- and redox-balance targeted treatments.
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Affiliation(s)
- Michael Müller
- Georg-August-Universität Göttingen, Universitätsmedizin Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Humboldtallee 23, D-37073 Göttingen, Germany; Zentrum Physiologie und Pathophysiologie, Institut für Neuro-und Sinnesphysiologie, Humboldtallee 23, D-37073 Göttingen, Germany.
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4
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Chen Y, Yu J, Niu Y, Qin D, Liu H, Li G, Hu Y, Wang J, Lu Y, Kang Y, Jiang Y, Wu K, Li S, Wei J, He J, Wang J, Liu X, Luo Y, Si C, Bai R, Zhang K, Liu J, Huang S, Chen Z, Wang S, Chen X, Bao X, Zhang Q, Li F, Geng R, Liang A, Shen D, Jiang T, Hu X, Ma Y, Ji W, Sun YE. Modeling Rett Syndrome Using TALEN-Edited MECP2 Mutant Cynomolgus Monkeys. Cell 2017; 169:945-955.e10. [PMID: 28525759 DOI: 10.1016/j.cell.2017.04.035] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 03/07/2017] [Accepted: 04/25/2017] [Indexed: 02/05/2023]
Abstract
Gene-editing technologies have made it feasible to create nonhuman primate models for human genetic disorders. Here, we report detailed genotypes and phenotypes of TALEN-edited MECP2 mutant cynomolgus monkeys serving as a model for a neurodevelopmental disorder, Rett syndrome (RTT), which is caused by loss-of-function mutations in the human MECP2 gene. Male mutant monkeys were embryonic lethal, reiterating that RTT is a disease of females. Through a battery of behavioral analyses, including primate-unique eye-tracking tests, in combination with brain imaging via MRI, we found a series of physiological, behavioral, and structural abnormalities resembling clinical manifestations of RTT. Moreover, blood transcriptome profiling revealed that mutant monkeys resembled RTT patients in immune gene dysregulation. Taken together, the stark similarity in phenotype and/or endophenotype between monkeys and patients suggested that gene-edited RTT founder monkeys would be of value for disease mechanistic studies as well as development of potential therapeutic interventions for RTT.
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Affiliation(s)
- Yongchang Chen
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China; Kunming Enovate Institute of Bioscience, Kunming 650000, China.
| | - Juehua Yu
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Yuyu Niu
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China; Kunming Enovate Institute of Bioscience, Kunming 650000, China
| | - Dongdong Qin
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Hailiang Liu
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Gang Li
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yingzhou Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Jiaojian Wang
- Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 625014, China
| | - Yi Lu
- Department of Medical Imaging, the First Affiliated Hospital, Kunming Medical University, Kunming 650032, China
| | - Yu Kang
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China; Kunming Enovate Institute of Bioscience, Kunming 650000, China
| | - Yong Jiang
- The First People's Hospital of Yunnan Province and The Affiliated Hospital of Kunming University of Science and Technology, Kunming 650032, China
| | - Kunhua Wu
- The First People's Hospital of Yunnan Province and The Affiliated Hospital of Kunming University of Science and Technology, Kunming 650032, China
| | - Siguang Li
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Jingkuan Wei
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Jing He
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Junbang Wang
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Xiaojing Liu
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Yuping Luo
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Chenyang Si
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China; Kunming Enovate Institute of Bioscience, Kunming 650000, China
| | - Raoxian Bai
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Kunshan Zhang
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Jie Liu
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Shaoyong Huang
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Zhenzhen Chen
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Shuang Wang
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Xiaoying Chen
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Xinhua Bao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Qingping Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Fuxing Li
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Rui Geng
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Aibin Liang
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Dinggang Shen
- Department of Radiology and BRIC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tianzi Jiang
- Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 625014, China; National Laboratory of Pattern Recognition, Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Xintian Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yuanye Ma
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China
| | - Weizhi Ji
- Yunnan Key Laboratory of Primate Biomedicine Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650051, China; Kunming Enovate Institute of Bioscience, Kunming 650000, China.
| | - Yi Eve Sun
- Translational Stem Cell Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Department of Psychiatry and Biobehavioral Sciences, UCLA Medical School, Los Angeles, CA 90095, USA.
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5
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Chelimsky G, Chelimsky T. Unusual Structural Autonomic Disorders Presenting in Pediatrics: Disorders Associated with Hypoventilation and Autonomic Neuropathies. Pediatr Clin North Am 2017; 64:173-183. [PMID: 27894444 DOI: 10.1016/j.pcl.2016.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Structural autonomic disorders (producing structural damage to the autonomic nervous system or autonomic centers) are far less common than functional autonomic disorders (reflected in abnormal function of a fundamentally normal autonomic nervous system) in children and teenagers. This article focuses on this uncommon first group in the pediatric clinic. These disorders are grouped into 2 main categories: those characterized by hypoventilation and those that feature an autonomic neuropathy.
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Affiliation(s)
- Gisela Chelimsky
- Division of Pediatric Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Thomas Chelimsky
- Department of Neurology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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6
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Veeraragavan S, Wan YW, Connolly DR, Hamilton SM, Ward CS, Soriano S, Pitcher MR, McGraw CM, Huang SG, Green JR, Yuva LA, Liang AJ, Neul JL, Yasui DH, LaSalle JM, Liu Z, Paylor R, Samaco RC. Loss of MeCP2 in the rat models regression, impaired sociability and transcriptional deficits of Rett syndrome. Hum Mol Genet 2016; 25:3284-3302. [PMID: 27365498 PMCID: PMC5179927 DOI: 10.1093/hmg/ddw178] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/18/2016] [Accepted: 06/08/2016] [Indexed: 01/31/2023] Open
Abstract
Mouse models of the transcriptional modulator Methyl-CpG-Binding Protein 2 (MeCP2) have advanced our understanding of Rett syndrome (RTT). RTT is a 'prototypical' neurodevelopmental disorder with many clinical features overlapping with other intellectual and developmental disabilities (IDD). Therapeutic interventions for RTT may therefore have broader applications. However, the reliance on the laboratory mouse to identify viable therapies for the human condition may present challenges in translating findings from the bench to the clinic. In addition, the need to identify outcome measures in well-chosen animal models is critical for preclinical trials. Here, we report that a novel Mecp2 rat model displays high face validity for modelling psychomotor regression of a learned skill, a deficit that has not been shown in Mecp2 mice. Juvenile play, a behavioural feature that is uniquely present in rats and not mice, is also impaired in female Mecp2 rats. Finally, we demonstrate that evaluating the molecular consequences of the loss of MeCP2 in both mouse and rat may result in higher predictive validity with respect to transcriptional changes in the human RTT brain. These data underscore the similarities and differences caused by the loss of MeCP2 among divergent rodent species which may have important implications for the treatment of individuals with disease-causing MECP2 mutations. Taken together, these findings demonstrate that the Mecp2 rat model is a complementary tool with unique features for the study of RTT and highlight the potential benefit of cross-species analyses in identifying potential disease-relevant preclinical outcome measures.
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Affiliation(s)
- Surabi Veeraragavan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Daniel R Connolly
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Christopher S Ward
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sirena Soriano
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Meagan R Pitcher
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Christopher M McGraw
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Sharon G Huang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Lisa A Yuva
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Agnes J Liang
- Department of Molecular and Human Genetics
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jeffrey L Neul
- Department of Pediatrics, Section of Neurology
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Dag H Yasui
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Janine M LaSalle
- Rowe Program in Human Genetics, University of California Davis, Davis, CA, USA
| | - Zhandong Liu
- Department of Pediatrics, Section of Neurology
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | | | - Rodney C Samaco
- Department of Molecular and Human Genetics
- Program in Translational Biology and Molecular Medicine
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
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7
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Abstract
Rett syndrome is an extremely disabling X-linked nervous system disorder that mainly affects girls in early childhood and causes autism-like behavior, severe intellectual disability, seizures, sleep disturbances, autonomic instability, and other disorders due to mutations in the MeCP2 (methyl CpG-binding protein 2) transcription factor. The disorder targets synapses and synaptic plasticity and has been shown to disrupt the balance between glutamate excitatory synapses and GABAergic inhibitory synapses. In fact, it can be argued that Rett syndrome is primarily a disorder of synaptic plasticity and that agents that can correct this imbalance may have beneficial effects on brain development. This review briefly summarizes the link between disrupted synaptic plasticity mechanisms and Rett syndrome and early clinical trials that aim to target these abnormalities to improve the outcome for these severely disabled children.
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Affiliation(s)
- Michael Johnston
- Developmental Neuroscience Laboratory, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, USA; Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mary E Blue
- Developmental Neuroscience Laboratory, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sakkubai Naidu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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8
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Navlakha S, Barth AL, Bar-Joseph Z. Decreasing-Rate Pruning Optimizes the Construction of Efficient and Robust Distributed Networks. PLoS Comput Biol 2015. [PMID: 26217933 PMCID: PMC4517947 DOI: 10.1371/journal.pcbi.1004347] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Robust, efficient, and low-cost networks are advantageous in both biological and engineered systems. During neural network development in the brain, synapses are massively over-produced and then pruned-back over time. This strategy is not commonly used when designing engineered networks, since adding connections that will soon be removed is considered wasteful. Here, we show that for large distributed routing networks, network function is markedly enhanced by hyper-connectivity followed by aggressive pruning and that the global rate of pruning, a developmental parameter not previously studied by experimentalists, plays a critical role in optimizing network structure. We first used high-throughput image analysis techniques to quantify the rate of pruning in the mammalian neocortex across a broad developmental time window and found that the rate is decreasing over time. Based on these results, we analyzed a model of computational routing networks and show using both theoretical analysis and simulations that decreasing rates lead to more robust and efficient networks compared to other rates. We also present an application of this strategy to improve the distributed design of airline networks. Thus, inspiration from neural network formation suggests effective ways to design distributed networks across several domains.
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Affiliation(s)
- Saket Navlakha
- Center for Integrative Biology, The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Alison L. Barth
- Department of Biological Sciences, Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (ALB); (ZBJ)
| | - Ziv Bar-Joseph
- Lane Center for Computational Biology, Machine Learning Department, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (ALB); (ZBJ)
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9
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Tarquinio DC, Hou W, Neul JL, Lane JB, Barnes KV, O’Leary HM, Bruck NM, Kaufmann WE, Motil KJ, Glaze DG, Skinner SA, Annese F, Baggett L, Barrish JO, Geerts SP, Percy AK. Age of diagnosis in Rett syndrome: patterns of recognition among diagnosticians and risk factors for late diagnosis. Pediatr Neurol 2015; 52:585-91.e2. [PMID: 25801175 PMCID: PMC4442062 DOI: 10.1016/j.pediatrneurol.2015.02.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/06/2015] [Accepted: 02/09/2015] [Indexed: 10/24/2022]
Abstract
PURPOSE Diagnosis of Rett syndrome (RTT) is often delayed. We sought to determine the type of physician who typically makes the RTT diagnosis and to identify risk factors for delayed diagnosis. METHODS A total of 1085 participants from the multicenter longitudinal RTT natural history study with classic and atypical RTT were recruited between 2006 and 2014. Age of diagnosis, diagnostician, diagnostic criteria, and clinical and developmental data were collected. RESULTS Among 919 classic and 166 atypical RTT participants, the median diagnosis age was 2.7 years (interquartile range 2.0-4.1) in classic and 3.8 years (interquartile range 2.3-6.9) in atypical RTT. Pediatricians made the diagnosis of classic RTT rarely (5.2%); however, the proportion diagnosed by pediatricians has increased since 2006. Since the first diagnostic criteria, the age of diagnosis decreased among subspecialists but not pediatricians. Odds of a pediatrician making the diagnosis of classic RTT were higher if a child stopped responding to parental interaction, and lower if they possessed gastroesophageal reflux, specific stereotypies, lost babbling, or the ability to follow commands. Delayed acquisition of basic gross motor skills or finger feeding was associated with younger diagnosis; delayed acquisition of higher level fine motor skills, later onset of supportive features, and normal head circumference were associated with late diagnosis. Thirty-three percent with microcephaly before 2.5 years were diagnosed after the median age of 2.7 years. CONCLUSIONS Age of RTT diagnosis has improved among subspecialists, and pediatricians have made the diagnosis of classic RTT more frequently since 2006. Strategies for educating diagnosticians should incorporate specific risk factors for delayed diagnosis.
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Affiliation(s)
| | - Wei Hou
- Stony Brook University Medical Center, Stony Brook, NY
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10
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Thomas MS, Davis R, Karmiloff-Smith A, Knowland VC, Charman T. The over-pruning hypothesis of autism. Dev Sci 2015; 19:284-305. [DOI: 10.1111/desc.12303] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 02/06/2015] [Indexed: 01/05/2023]
Affiliation(s)
- Michael S.C. Thomas
- Developmental Neurocognition Lab; Centre for Brain & Cognitive Development, Birkbeck,University of London; UK
| | - Rachael Davis
- Developmental Neurocognition Lab; Centre for Brain & Cognitive Development, Birkbeck,University of London; UK
| | - Annette Karmiloff-Smith
- Developmental Neurocognition Lab; Centre for Brain & Cognitive Development, Birkbeck,University of London; UK
| | | | - Tony Charman
- Institute of Psychiatry; Psychology & Neuroscience, King's College London; UK
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11
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Johnston MV, Ammanuel S, O'Driscoll C, Wozniak A, Naidu S, Kadam SD. Twenty-four hour quantitative-EEG and in-vivo glutamate biosensor detects activity and circadian rhythm dependent biomarkers of pathogenesis in Mecp2 null mice. Front Syst Neurosci 2014; 8:118. [PMID: 25018705 PMCID: PMC4072927 DOI: 10.3389/fnsys.2014.00118] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/02/2014] [Indexed: 11/13/2022] Open
Abstract
Mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (Mecp2) cause most cases of Rett syndrome (RTT). Currently there is no cure for RTT. Abnormal EEGs are found in 100% of RTT cases and are associated with severe sleep dysfunction, the cause of which is not well understood. Mice deficient in MeCP2 protein have been studied and characterized for their neuropathological and behavioral deficits to better understand RTT. With the goal to study the non-ictal EEG correlates in symptomatic Mecp2 KO mice (Mecp2(tm1.1Bird/y)), and determine novel EEG biomarkers of their reported progressive neurodegeneration, we used 24 h video-EEG/EMG with synchronous in-vivo cortical glutamate biosensor in the frontal cortex. We scored the EEG for activity states and spectral analysis was performed to evaluate correlations to the synchronous extracellular glutamate fluctuations underlying Mecp2 inactivation as compared to WT. Significant alterations in sleep structure due to dark cycle-specific long wake states and poor quality of slow-wave sleep were associated with a significant increase in glutamate loads per activity cycle. The dynamics of the activity-state-dependent physiological rise and fall of glutamate indicative of glutamate homeostasis were significantly altered in the KO mice. Colorimetric quantitation of absolute glutamate levels in frontal cortex also indicated the presence of significantly higher levels in KO. This study for the first time found evidence of uncompensated sleep deprivation-like EEG biomarkers that were associated with glutamate homeostatic dysfunction in the Mecp2 KO mice.
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Affiliation(s)
- Michael V Johnston
- Neuroscience Laboratory, Departments of Neurology and Pediatrics, Hugo Moser Research Institute at Kennedy Krieger, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Simon Ammanuel
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Cliona O'Driscoll
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Hugo Moser Research Institute at Kennedy Krieger, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Amy Wozniak
- Biostatistics Center, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Sakkubai Naidu
- Departments of Neurology and Pediatrics, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Departments of Neurology, Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins University School of Medicine Baltimore, MD, USA
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12
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Navlakha S, Suhan J, Barth AL, Bar-Joseph Z. A high-throughput framework to detect synapses in electron microscopy images. Bioinformatics 2013; 29:i9-17. [PMID: 23813014 PMCID: PMC3694654 DOI: 10.1093/bioinformatics/btt222] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Motivation: Synaptic connections underlie learning and memory in the brain and are dynamically formed and eliminated during development and in response to stimuli. Quantifying changes in overall density and strength of synapses is an important pre-requisite for studying connectivity and plasticity in these cases or in diseased conditions. Unfortunately, most techniques to detect such changes are either low-throughput (e.g. electrophysiology), prone to error and difficult to automate (e.g. standard electron microscopy) or too coarse (e.g. magnetic resonance imaging) to provide accurate and large-scale measurements. Results: To facilitate high-throughput analyses, we used a 50-year-old experimental technique to selectively stain for synapses in electron microscopy images, and we developed a machine-learning framework to automatically detect synapses in these images. To validate our method, we experimentally imaged brain tissue of the somatosensory cortex in six mice. We detected thousands of synapses in these images and demonstrate the accuracy of our approach using cross-validation with manually labeled data and by comparing against existing algorithms and against tools that process standard electron microscopy images. We also used a semi-supervised algorithm that leverages unlabeled data to overcome sample heterogeneity and improve performance. Our algorithms are highly efficient and scalable and are freely available for others to use. Availability: Code is available at http://www.cs.cmu.edu/∼saketn/detect_synapses/ Contact:zivbj@cs.cmu.edu
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Affiliation(s)
- Saket Navlakha
- Machine Learning Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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13
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Panighini A, Duranti E, Santini F, Maffei M, Pizzorusso T, Funel N, Taddei S, Bernardini N, Ippolito C, Virdis A, Costa M. Vascular dysfunction in a mouse model of Rett syndrome and effects of curcumin treatment. PLoS One 2013; 8:e64863. [PMID: 23705018 PMCID: PMC3660336 DOI: 10.1371/journal.pone.0064863] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 04/22/2013] [Indexed: 02/07/2023] Open
Abstract
Mutations in the coding sequence of the X-linked gene MeCP2 (Methyl CpG–binding protein) are present in around 80% of patients with Rett Syndrome, a common cause of intellectual disability in female and to date without any effective pharmacological treatment. A relevant, and so far unexplored feature of RTT patients, is a marked reduction in peripheral circulation. To investigate the relationship between loss of MeCP2 and this clinical aspect, we used the MeCP2 null mouse model B6.129SF1-MeCP2tm1Jae for functional and pharmacological studies. Functional experiments were performed on isolated resistance mesenteric vessels, mounted on a pressurized myograph. Vessels from female MeCP2+/− mice show a reduced endothelium-dependent relaxation, due to a reduced Nitric Oxide (NO) availability secondary to an increased Reactive Oxygen Species (ROS) generation. Such functional aspects are associated with an intravascular increase in superoxide anion production, and a decreased vascular eNOS expression. These alterations are reversed by curcumin administration (5% (w/w) dietary curcumin for 21 days), which restores endothelial NO availability, decreases intravascular ROS production and normalizes vascular eNOS gene expression. In conclusion our findings highlight alterations in the vascular/endothelial system in the absence of a correct function of MeCP2, and uncover related cellular/molecular mechanisms that are rescued by an anti-oxidant treatment.
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MESH Headings
- Animals
- Blood Vessels/drug effects
- Blood Vessels/physiopathology
- Curcumin/administration & dosage
- Curcumin/pharmacology
- Curcumin/therapeutic use
- Disease Models, Animal
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Female
- Gene Expression Regulation, Enzymologic/drug effects
- Immunohistochemistry
- Malondialdehyde/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide Synthase Type III/genetics
- Nitric Oxide Synthase Type III/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rett Syndrome/complications
- Rett Syndrome/drug therapy
- Rett Syndrome/physiopathology
- Superoxides/metabolism
- Time Factors
- Vascular Diseases/complications
- Vascular Diseases/drug therapy
- Vascular Diseases/physiopathology
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Affiliation(s)
- Anna Panighini
- Institute of Neuroscience, Italian National Research Council (CNR), Pisa, Italy
| | - Emiliano Duranti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Ferruccio Santini
- Department of Endocrinology and Kidney; University-Hospital of Pisa, Pisa, Italy
| | - Margherita Maffei
- Department of Endocrinology and Kidney; University-Hospital of Pisa, Pisa, Italy
- Dulbecco Telethon Institute, Rome, Italy
- Institute of Food Science, CNR, Avellino, Italy
| | - Tommaso Pizzorusso
- Institute of Neuroscience, Italian National Research Council (CNR), Pisa, Italy
- Institute of Psychology, University of Florence, Florence, Italy
| | - Niccola Funel
- Department of Surgery, University of Pisa, Pisa, Italy
| | - Stefano Taddei
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Nunzia Bernardini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Chiara Ippolito
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Agostino Virdis
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
- * E-mail: (AV); (MC)
| | - Mario Costa
- Institute of Neuroscience, Italian National Research Council (CNR), Pisa, Italy
- Scuola Normale Superiore, Pisa, Italy
- * E-mail: (AV); (MC)
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14
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Lang M, Wither RG, Brotchie JM, Wu C, Zhang L, Eubanks JH. Selective preservation of MeCP2 in catecholaminergic cells is sufficient to improve the behavioral phenotype of male and female Mecp2-deficient mice. Hum Mol Genet 2012; 22:358-71. [PMID: 23077217 DOI: 10.1093/hmg/dds433] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused primarily by mutations of the X-linked MECP2 gene. Although the loss of MeCP2 function affects many neural systems, impairments of catecholaminergic function have been hypothesized to underlie several of the cardinal behavioral deficits of RTT patients and Mecp2-deficient mice. Although recent Mecp2 reactivation studies indicate that RTT may be a reversible condition, it remains unclear whether specifically preserving Mecp2 function within a specific system will be sufficient to convey beneficial effects. Here, we test whether the selective preservation of Mecp2 within catecholaminergic cells will improve the phenotype of Mecp2-deficient mice. Our results show that this targeted preservation of Mecp2 significantly improves the lifespan, phenotypic severity and cortical epileptiform discharge activity of both male and female Mecp2-deficient mice. Further, we found that the catecholaminergic preservation of Mecp2 also improves the ambulatory rate, rearing activity, motor coordination, anxiety and nest-building performances of Mecp2-deficient mice of each gender. Interestingly, our results also revealed a gender-specific improvement, as specific cortical and hippocampal electroencephalographic abnormalities were significantly improved in male, but not female, rescue mice. Collectively, these results support the role of the catecholaminergic system in the pathogenesis of RTT and provide proof-of-principle that restoring MeCP2 function within this specific system could represent a treatment strategy for RTT.
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Affiliation(s)
- Min Lang
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, 399 Bathurst Street, Toronto, ON, Canada M5T 2S8
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15
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16
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Robertson HR, Feng G. Annual Research Review: Transgenic mouse models of childhood-onset psychiatric disorders. J Child Psychol Psychiatry 2011; 52:442-75. [PMID: 21309772 PMCID: PMC3075087 DOI: 10.1111/j.1469-7610.2011.02380.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Childhood-onset psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), mood disorders, obsessive compulsive spectrum disorders (OCSD), and schizophrenia (SZ), affect many school-age children, leading to a lower quality of life, including difficulties in school and personal relationships that persist into adulthood. Currently, the causes of these psychiatric disorders are poorly understood, resulting in difficulty diagnosing affected children, and insufficient treatment options. Family and twin studies implicate a genetic contribution for ADHD, ASD, mood disorders, OCSD, and SZ. Identification of candidate genes and chromosomal regions associated with a particular disorder provide targets for directed research, and understanding how these genes influence the disease state will provide valuable insights for improving the diagnosis and treatment of children with psychiatric disorders. Transgenic mouse models are one important approach in the study of human diseases, allowing for the use of a variety of experimental approaches to dissect the contribution of a specific chromosomal or genetic abnormality in human disorders. While it is impossible to model an entire psychiatric disorder in a single mouse model, these models can be extremely valuable in dissecting out the specific role of a gene, pathway, neuron subtype, or brain region in a particular abnormal behavior. In this review we discuss existing transgenic mouse models for childhood-onset psychiatric disorders. We compare the strength and weakness of various transgenic mouse models proposed for each of the common childhood-onset psychiatric disorders, and discuss future directions for the study of these disorders using cutting-edge genetic tools.
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Affiliation(s)
- Holly R. Robertson
- Duke University, Neurobiology Department Durham, N.C.,Massachusetts Institute of Technology, Brain and Cognitive Sciences Department Cambridge, M.A
| | - Guoping Feng
- Duke University, Neurobiology Department Durham, N.C.,Massachusetts Institute of Technology, Brain and Cognitive Sciences Department Cambridge, M.A
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17
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Maliszewska-Cyna E, Bawa D, Eubanks JH. Diminished prevalence but preserved synaptic distribution of N-methyl-D-aspartate receptor subunits in the methyl CpG binding protein 2(MeCP2)-null mouse brain. Neuroscience 2010; 168:624-32. [PMID: 20381590 DOI: 10.1016/j.neuroscience.2010.03.065] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/29/2010] [Accepted: 03/30/2010] [Indexed: 10/19/2022]
Abstract
In this study, we examined the prevalence and distribution of NMDA receptor subunits within crude synaptic membranes derived from the brains of mice lacking methyl CpG binding protein 2 (MeCP2). Our results show that the distribution of NMDA receptor subunits within the detergent soluble, detergent resistant, and postsynaptic density microdomains is preserved at MeCP2-null synapses. However, analysis of the NMDA receptor subunit expression revealed a decrease in the prevalence of the GluN1 and GluN2A subunits in MeCP2-null tissue. Collectively, these results indicate that synaptic membrane microdomains at synapses of the MeCP2-null brain develop normally, and that NMDA receptor subunits are properly targeted and distributed within them. The under-representation of the GluN1 and GluN2A subunits suggests that MeCP2-null synapses contain fewer mature NMDA receptor complexes, and raises the possibility that impaired NMDA receptor ontogeny could contribute to Rett syndrome pathophysiology.
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Affiliation(s)
- E Maliszewska-Cyna
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada
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18
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Hite KC, Adams VH, Hansen JC. Recent advances in MeCP2 structure and function. Biochem Cell Biol 2009; 87:219-27. [PMID: 19234536 DOI: 10.1139/o08-115] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutations in methyl DNA binding protein 2 (MeCP2) cause the neurodevelopmental disorder Rett syndrome (RTT). The mechanism(s) by which the native MeCP2 protein operates in the cell are not well understood. Historically, MeCP2 has been characterized as a proximal gene silencer with 2 functional domains: a methyl DNA binding domain and a transcription repression domain. However, several lines of new data indicate that MeCP2 structure and function relationships are more complex. In this review, we first discuss recent studies that have advanced understanding of the basic structural biochemistry of MeCP2. This is followed by an analysis of cell-based experiments suggesting MeCP2 is a regulator, rather than a strict silencer, of transcription. The new data establish MeCP2 as a multifunctional nuclear protein, with potentially important roles in chromatin architecture, regulation of RNA splicing, and active transcription. We conclude by discussing clinical correlations between domain-specific mutations and RTT pathology to stress that all structural domains of MeCP2 are required to properly mediate cellular function of the intact protein.
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Affiliation(s)
- Kristopher C Hite
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA.
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19
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Abstract
The autisms and epilepsies are heterogeneous disorders that have diverse etiologies and pathologies. The severity of impairment and of symptoms associated with autism or with particular epilepsy syndromes reflects focal or global, structurally abnormal or dysfunctional neuronal networks. The complex relationship between autism and epilepsy, as reflected in the autism-epilepsy phenotype, provides a bridge to further knowledge of shared neuronal networks that can account for both the autisms and the epilepsies. Although epilepsy is not a causal factor for autism, increased understanding of common genetic and molecular biological mechanisms of the autism-epilepsy phenotype has provided insight into the pathophysiology of the autisms. The autism-epilepsy phenotype provides a novel model to the study of interventions that may have a positive modulating effects on social cognitive outcome.
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Affiliation(s)
- Roberto Tuchman
- Department of Neurology, University of Miami, Miami Children's Hospital, Dan Marino Center, 2900 South Commerce Parkway, Weston, FL, USA.
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20
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Crespi B. Genomic imprinting in the development and evolution of psychotic spectrum conditions. Biol Rev Camb Philos Soc 2008; 83:441-93. [PMID: 18783362 DOI: 10.1111/j.1469-185x.2008.00050.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
I review and evaluate genetic and genomic evidence salient to the hypothesis that the development and evolution of psychotic spectrum conditions have been mediated in part by alterations of imprinted genes expressed in the brain. Evidence from the genetics and genomics of schizophrenia, bipolar disorder, major depression, Prader-Willi syndrome, Klinefelter syndrome, and other neurogenetic conditions support the hypothesis that the etiologies of psychotic spectrum conditions commonly involve genetic and epigenetic imbalances in the effects of imprinted genes, with a bias towards increased relative effects from imprinted genes with maternal expression or other genes favouring maternal interests. By contrast, autistic spectrum conditions, including Kanner autism, Asperger syndrome, Rett syndrome, Turner syndrome, Angelman syndrome, and Beckwith-Wiedemann syndrome, commonly engender increased relative effects from paternally expressed imprinted genes, or reduced effects from genes favouring maternal interests. Imprinted-gene effects on the etiologies of autistic and psychotic spectrum conditions parallel the diametric effects of imprinted genes in placental and foetal development, in that psychotic spectrum conditions tend to be associated with undergrowth and relatively-slow brain development, whereas some autistic spectrum conditions involve brain and body overgrowth, especially in foetal development and early childhood. An important role for imprinted genes in the etiologies of psychotic and autistic spectrum conditions is consistent with neurodevelopmental models of these disorders, and with predictions from the conflict theory of genomic imprinting.
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Affiliation(s)
- Bernard Crespi
- Department of Biosciences, Simon Fraser University, Burnaby BCV5A1S6, Canada.
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21
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Molina J, Carmona-Mora P, Chrast J, Krall PM, Canales CP, Lupski JR, Reymond A, Walz K. Abnormal social behaviors and altered gene expression rates in a mouse model for Potocki-Lupski syndrome. Hum Mol Genet 2008; 17:2486-95. [PMID: 18469339 DOI: 10.1093/hmg/ddn148] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Potocki-Lupski syndrome (PTLS) is associated with a microduplication of 17p11.2. Clinical features include multiple congenital and neurobehavioral abnormalities and autistic features. We have generated a PTLS mouse model, Dp(11)17/+, that recapitulates some of the physical and neurobehavioral phenotypes present in patients. Here, we investigated the social behavior and gene expression pattern of this mouse model in a pure C57BL/6-Tyr(c-Brd) genetic background. Dp(11)17/+ male mice displayed normal home-cage behavior but increased anxiety and increased dominant behavior in specific tests. A subtle impairment in the preference for a social target versus an inanimate target and abnormal preference for social novelty (the preference to explore an unfamiliar mouse versus a familiar one) was also observed. Our results indicate that these animals could provide a valuable model to identify the specific gene(s) that confer abnormal social behaviors and that map within this delimited genomic deletion interval. In a first attempt to identify candidate genes and for elucidating the mechanisms of regulation of these important phenotypes, we directly assessed the relative transcription of genes within and around this genomic interval. In this mouse model, we found that candidates genes include not only most of the duplicated genes, but also normal-copy genes that flank the engineered interval; both categories of genes showed altered expression levels in the hippocampus of Dp(11)17/+ mice.
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Abstract
Autism is a neurodevelopmental syndrome with markedly high heritability. The diagnostic indicators of autism are core behavioral symptoms, rather than definitive neuropathological markers. Etiology is thought to involve complex, multigenic interactions and possible environmental contributions. In this review, we focus on genetic pathways with multiple members represented in autism candidate gene lists. Many of these pathways can also be impinged upon by environmental risk factors associated with the disorder. The mouse model system provides a method to experimentally manipulate candidate genes for autism susceptibility, and to use environmental challenges to drive aberrant gene expression and cell pathology early in development. Mouse models for fragile X syndrome, Rett syndrome and other disorders associated with autistic-like behavior have elucidated neuropathology that might underlie the autism phenotype, including abnormalities in synaptic plasticity. Mouse models have also been used to investigate the effects of alterations in signaling pathways on neuronal migration, neurotransmission and brain anatomy, relevant to findings in autistic populations. Advances have included the evaluation of mouse models with behavioral assays designed to reflect disease symptoms, including impaired social interaction, communication deficits and repetitive behaviors, and the symptom onset during the neonatal period. Research focusing on the effect of gene-by-gene interactions or genetic susceptibility to detrimental environmental challenges may further understanding of the complex etiology for autism.
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Affiliation(s)
- S S Moy
- Neurodevelopmental Disorders Research Center, Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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23
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Xi CY, Ma HW, Lu Y, Zhao YJ, Hua TY, Zhao Y, Ji YH. MeCP2 gene mutation analysis in autistic boys with developmental regression. Psychiatr Genet 2007; 17:113-6. [PMID: 17413451 DOI: 10.1097/ypg.0b013e3280114a5c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Autism and Rett syndrome are both pervasive developmental disorders and share many characteristics in common. One of these features is developmental regression with loss of social, cognitive and language skills after a period of apparently normal development during the first 1-2 years of life, which raises the question of whether there is a common pathway underlying regression in these two disorders. The Rett syndrome gene was identified as MeCP2 gene on Xq28, a powerful transcriptional repressor. To explore its possible role in the etiology of autism and involvement in regression, we searched for MeCP2 gene mutations in a well characterized sample of 31 autistic boys with developmental regression by direct sequencing. One sequence variant in 3' untranslated region was observed. The patient inherited the variant from his unaffected mother, so it may be a rare polymorphism. No coding sequence variant was found in any of the patients tested. We conclude that mutations in the coding sequence of MeCP2 are not a frequent cause of regression in autism. The long 3' untranslated region of MeCP2 is highly conserved across species, suggesting that they are important for the post-transcriptional regulation of MeCP2 gene. It may be worthwhile extending the mutation screening, with a larger sample of strictly defined phenotype, to regulatory elements and untranslated regions of this gene, to explore to what degree MeCP2 gene is involved in the etiology of autism and its possible role in the regression of autism.
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Affiliation(s)
- Chun-Yan Xi
- Department of Developmental Pediatrics, The 2nd Hospital, China Medical University, Shenyang, China.
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24
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Jordan C, Li HH, Kwan HC, Francke U. Cerebellar gene expression profiles of mouse models for Rett syndrome reveal novel MeCP2 targets. BMC MEDICAL GENETICS 2007; 8:36. [PMID: 17584923 PMCID: PMC1931432 DOI: 10.1186/1471-2350-8-36] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 06/20/2007] [Indexed: 01/01/2023]
Abstract
Background MeCP2, methyl-CpG-binding protein 2, binds to methylated cytosines at CpG dinucleotides, as well as to unmethylated DNA, and affects chromatin condensation. MECP2 mutations in females lead to Rett syndrome, a neurological disorder characterized by developmental stagnation and regression, loss of purposeful hand movements and speech, stereotypic hand movements, deceleration of brain growth, autonomic dysfunction and seizures. Most mutations occur de novo during spermatogenesis. Located at Xq28, MECP2 is subject to X inactivation, and affected females are mosaic. Rare hemizygous males suffer from a severe congenital encephalopathy. Methods To identify the pathways mis-regulated by MeCP2 deficiency, microarray-based global gene expression studies were carried out in cerebellum of Mecp2 mutant mice. We compared transcript levels in mutant/wildtype male sibs of two different MeCP2-deficient mouse models at 2, 4 and 8 weeks of age. Increased transcript levels were evaluated by real-time quantitative RT-PCR. Chromatin immunoprecipitation assays were used to document in vivo MeCP2 binding to promoter regions of candidate target genes. Results Of several hundred genes with altered expression levels in the mutants, twice as many were increased than decreased, and only 27 were differentially expressed at more than one time point. The number of misregulated genes was 30% lower in mice with the exon 3 deletion (Mecp2tm1.1Jae) than in mice with the larger deletion (Mecp2tm1.1Bird). Between the mutants, few genes overlapped at each time point. Real-time quantitative RT-PCR assays validated increased transcript levels for four genes: Irak1, interleukin-1 receptor-associated kinase 1; Fxyd1, phospholemman, associated with Na, K-ATPase;Reln, encoding an extracellular signaling molecule essential for neuronal lamination and synaptic plasticity; and Gtl2/Meg3, an imprinted maternally expressed non-translated RNA that serves as a host gene for C/D box snoRNAs and microRNAs. Chromatin immunoprecipitation assays documented in vivo MeCP2 binding to promoter regions of Fxyd1, Reln, and Gtl2. Conclusion Transcriptional profiling of cerebellum failed to detect significant global changes in Mecp2-mutant mice. Increased transcript levels of Irak1, Fxyd1, Reln, and Gtl2 may contribute to the neuronal dysfunction in MeCP2-deficient mice and individuals with Rett syndrome. Our data provide testable hypotheses for future studies of the regulatory or signaling pathways that these genes act on.
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Affiliation(s)
- ChaRandle Jordan
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305-5323, USA
| | - Hong Hua Li
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305-5323, USA
| | - Helen C Kwan
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305-5323, USA
| | - Uta Francke
- Department of Genetics, Stanford University School of Medicine, Stanford CA 94305-5323, USA
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25
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Abstract
Epilepsy is quite common in autism spectrum disorders, and it is increasingly recognized as an additional clinical problem that must be dealt with. The rate of comorbidity varies, depending upon the age and type of disorder, and currently the conservative estimate of comorbidity cases is 20-25% of the whole spectrum. Major risk factors for seizure occurrence are mental retardation and additional neurological disorders, as well as some specific associated medical conditions. Autism with regression has been reported in one-third of children with previously normal or nearly normal development. In an unknown proportion of these subjects, epileptic disorders are concomitant, leading to so-called autistic epileptiform regression. Furthermore, epileptiform abnormalities without seizures are frequent in this population and their role in the development of the nuclear disturbances of autism is controversial. The therapeutic approaches to epilepsy in autism are conventional treatments, yet when seizures are not evident, there is still controversy. Anticonvulsant medications could also potentially interfere with mood and behavioral disturbances frequently observed in ASD. The current understanding of the association between epilepsy and autism is still limited, but from a clinical point of view this association should not be overlooked, and it should be routinely investigated.
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Affiliation(s)
- Roberto Canitano
- Division of Child Neuropsychiatry, General University Hospital of Siena, Viale Bracci 14, 53100 Siena, Italy.
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26
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Moy SS, Nadler JJ, Young NB, Perez A, Holloway LP, Barbaro RP, Barbaro JR, Wilson LM, Threadgill DW, Lauder JM, Magnuson TR, Crawley JN. Mouse behavioral tasks relevant to autism: phenotypes of 10 inbred strains. Behav Brain Res 2007; 176:4-20. [PMID: 16971002 PMCID: PMC1857288 DOI: 10.1016/j.bbr.2006.07.030] [Citation(s) in RCA: 600] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 07/24/2006] [Accepted: 07/31/2006] [Indexed: 01/19/2023]
Abstract
Three defining clinical symptoms of autism are aberrant reciprocal social interactions, deficits in social communication, and repetitive behaviors, including motor stereotypies and insistence on sameness. We developed a set of behavioral tasks designed to model components of these core symptoms in mice. Male mice from 10 inbred strains were characterized in assays for sociability, preference for social novelty, and reversal of the spatial location of the reinforcer in T-maze and Morris water maze tasks. Six strains, C57BL/6J, C57L/J, DBA/2J, FVB/NJ, C3H/HeJ, and AKR/J, showed significant levels of sociability, while A/J, BALB/cByJ, BTBR T(+)tf/J, and 129S1/SvImJ mice did not. C57BL/6J, C57L/J, DBA/2J, FVB/NJ, BALB/cByJ, and BTBR T(+)tf/J showed significant preference for social novelty, while C3H/HeJ, AKR/J, A/J, and 129S1/SvImJ did not. Normal scores on relevant control measures confirmed general health and physical abilities in all strains, ruling out artifactual explanations for social deficits. Elevated plus maze scores confirmed high anxiety-like behaviors in A/J, BALB/cByJ, and 129S1/SvImJ, which could underlie components of their low social approach. Strains that showed high levels of performance on acquisition of a T-maze task were also able to reach criterion for reversal learning. On the Morris water maze task, DBA/2J, AKR/J, BTBR T(+)tf/J, and 129S1/SvImJ failed to show significant quadrant preference during the reversal probe trial. These results highlight a dissociation between social task performance and reversal learning. BTBR T(+)tf/J is a particularly interesting strain, displaying both low social approach and resistance to change in routine on the water maze, consistent with an autism-like phenotype. Our multitask strategy for modeling symptoms of autism will be useful for investigating targeted and random gene mutations, QTLs, and microarray analyses.
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Affiliation(s)
- Sheryl S Moy
- North Carolina STAART Center for Autism Research, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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27
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Autism and Pervasive Developmental Disorders. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0074-7750(07)34005-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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28
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Badcock C, Crespi B. Imbalanced genomic imprinting in brain development: an evolutionary basis for the aetiology of autism. J Evol Biol 2006; 19:1007-32. [PMID: 16780503 DOI: 10.1111/j.1420-9101.2006.01091.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We describe a new hypothesis for the development of autism, that it is driven by imbalances in brain development involving enhanced effects of paternally expressed imprinted genes, deficits of effects from maternally expressed genes, or both. This hypothesis is supported by: (1) the strong genomic-imprinting component to the genetic and developmental mechanisms of autism, Angelman syndrome, Rett syndrome and Turner syndrome; (2) the core behavioural features of autism, such as self-focused behaviour, altered social interactions and language, and enhanced spatial and mechanistic cognition and abilities, and (3) the degree to which relevant brain functions and structures are altered in autism and related disorders. The imprinted brain theory of autism has important implications for understanding the genetic, epigenetic, neurological and cognitive bases of autism, as ultimately due to imbalances in the outcomes of intragenomic conflict between effects of maternally vs. paternally expressed genes.
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Affiliation(s)
- C Badcock
- Department of Sociology, London School of Economics, London, UK
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Abstract
We examined somatic growth, somatosensory reflexes, and ultrasonic calls from postnatal day 3 to day 18 in Mecp2 mutant mice, a mouse model of Rett syndrome. Both Mecp2 null male and Mecp2 heterozygous female mice exhibited normal somatic growth, but transient delays in the development of some reflexes relative to sex-matched wild-type mice. Both Mecp2 null male and heterozygous female mice exhibited dramatic increases in ultrasonic vocalizations in response to social isolation; these differences were evident as early as postnatal day 5. These results suggest very early abnormalities in sensory reflex development and behavioral responsiveness in the Mecp2 mutants that may provide a target for early therapeutic intervention.
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Affiliation(s)
- Jonathan D Picker
- Department of Genetics, Children's Hospital, Boston, Massachusetts, USA
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Young JI, Hong EP, Castle JC, Crespo-Barreto J, Bowman AB, Rose MF, Kang D, Richman R, Johnson JM, Berget S, Zoghbi HY. Regulation of RNA splicing by the methylation-dependent transcriptional repressor methyl-CpG binding protein 2. Proc Natl Acad Sci U S A 2005; 102:17551-8. [PMID: 16251272 PMCID: PMC1266160 DOI: 10.1073/pnas.0507856102] [Citation(s) in RCA: 342] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rett syndrome (RTT) is a postnatal neurodevelopmental disorder characterized by the loss of acquired motor and language skills, autistic features, and unusual stereotyped movements. RTT is caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2). Mutations in MECP2 cause a variety of neurodevelopmental disorders including X-linked mental retardation, psychiatric disorders, and some cases of autism. Although MeCP2 was identified as a methylation-dependent transcriptional repressor, transcriptional profiling of RNAs from mice lacking MeCP2 did not reveal significant gene expression changes, suggesting that MeCP2 does not simply function as a global repressor. Changes in expression of a few genes have been observed, but these alterations do not explain the full spectrum of Rett-like phenotypes, raising the possibility that additional MeCP2 functions play a role in pathogenesis. In this study, we show that MeCP2 interacts with the RNA-binding protein Y box-binding protein 1 and regulates splicing of reporter minigenes. Importantly, we found aberrant alternative splicing patterns in a mouse model of RTT. Thus, we uncovered a previously uncharacterized function of MeCP2 that involves regulation of splicing, in addition to its role as a transcriptional repressor.
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Affiliation(s)
- Juan I Young
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
PURPOSE OF REVIEW Nearly 70 reports on Rett syndrome were published in 2004. We have selected 51 articles, including clinical reports, on pathophysiology, genotype-phenotype correlation, and clinical and basic molecular biology studies. These articles explain how mutation of the gene (MECP2) for methyl-CpG-binding protein 2 causes the particular disorders of Rett syndrome, and also induces other neurodevelopmental disorders, clarifying the situation for future studies. RECENT FINDINGS The role of X-chromosome inactivation has been clarified in animal experiments. New isoforms of MeCP2 have been discovered and its functional characteristics are under research. Understanding of the influence of the MECP2 mutation on other neurodevelopmental disorders has increased. However, there is no apparent progress in neurophysiological studies. SUMMARY Clinical studies included the pathophysiology of stereotyped movement, and cardiac and respiratory disturbances, and there were four therapeutic trials including one for epilepsy. For genotype-phenotype correlation the role of X-chromosome inactivation was looked at and its basic mechanisms were studied extensively in animals. Characteristics of mutations in the C-terminus and the biological function of the new isoform, exon 1, were introduced. In studies on related neurodevelopmental disorders, a relationship is suggested between the MECP2 gene and autism-related gene, with overlapping pathways, but this is not common to other neurodevelopmental disorders. Developmental studies suggest an important role for MeCP2 in the formation and/or maintenance of synapses, and clarify the molecular biological aspects of Rett syndrome. However, early involvement of the aminergic neurons, suggested as the basic, pathognomonic lesion of Rett syndrome, has unfortunately not been investigated with the MECP2 mutation.
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Affiliation(s)
- Masaya Segawa
- Segawa Neurological Clinic for Children, Tokyo, Japan.
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Abstract
Of the recently discovered group of proteins that interpret DNA methylation signals by preferentially associating with methylated CpG dinucleotides, the methyl-CpG-binding protein 2 (MeCP2) has attracted considerable attention in view of its ability to repress transcription. The interest in MeCP2 dramatically increased following the discovery of mutated forms of the protein in patients with Rett syndrome, a neurodevelopmental disease. A connection with carcino-genesis has also been established. This review attempts to bring together and critically discuss recently acquired information about the molecular biology of the protein and its mechanism of action. A careful overview of the literature reveals the complexity of its activity, which goes well beyond the recognized chromatin connections. Finally, the newly established facts concerning the connection of MeCP2 to human disease are presented. Key words: methyl-CpG-binding proteins, MeCP2, transcription repression, chromatin modification, Rett syndrome, cancer.
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Affiliation(s)
- Jordanka Zlatanova
- Department of Molecular Biology, College of Agriculture, University of Wyoming, Laramie, WY 82071, USA.
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Dumont-Mathieu T, Fein D. Screening for autism in young children: The Modified Checklist for Autism in Toddlers (M-CHAT) and other measures. ACTA ACUST UNITED AC 2005; 11:253-62. [PMID: 16161090 DOI: 10.1002/mrdd.20072] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The literature on the importance of early identification and early intervention for children with developmental disabilities such as autism continues to grow. The increased prevalence of autistic spectrum disorders has fostered research efforts on the development and validation of autism-specific screening instruments for use with young children. There are currently several such autism-specific screening tools meant to be used with young children in various stages of development. Data from a few of these screening instruments have been published, and they include the Checklist for Autism in Toddlers (CHAT), Pervasive Developmental Disorders Screening Test (PDDST), Screening Tool for Autism in Two year olds (STAT), Checklist for Autism in Toddlers-23 (CHAT-23), and the Modified Checklist for Autism in Toddlers (M-CHAT). In this review, these five tools designed for use with children under three years old will be highlighted. In particular, the Modified Checklist for Autism in Toddlers (M-CHAT) will be discussed.
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Affiliation(s)
- Thyde Dumont-Mathieu
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, CT 06269-1020, USA.
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