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Canitano R, Bozzi Y. Autism Spectrum Disorder with Epilepsy: A Research Protocol for a Clinical and Genetic Study. Genes (Basel) 2023; 15:61. [PMID: 38254951 PMCID: PMC10815607 DOI: 10.3390/genes15010061] [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: 11/27/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Autism spectrum disorder (ASD) is a common neurodevelopmental condition affecting ~1% of people worldwide. Core ASD features present with impaired social communication abilities, repetitive and stereotyped behaviors, and atypical sensory responses and are often associated with a series of comorbidities. Among these, epilepsy is frequently observed. The co-occurrence of ASD and epilepsy is currently thought to result from common abnormal neurodevelopmental pathways, including an imbalanced excitation/inhibition ratio. However, the pathological mechanisms involved in ASD-epilepsy co-morbidity are still largely unknown. Here, we propose a research protocol aiming to investigate electrophysiological and genetic features in subjects with ASD and epilepsy. This study will include a detailed electroencephalographic (EEG) and blood transcriptomic characterization of subjects with ASD with and without epilepsy. The combined approach of EEG and transcriptomic studies in the same subjects will contribute to a novel stratification paradigm of the heterogeneous ASD population based on quantitative gene expression and neurophysiological biomarkers. In addition, our protocol has the potential to indicate new therapeutic options, thus amending the current condition of absence of data and guidelines for the treatment of ASD with epilepsy.
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Affiliation(s)
- Roberto Canitano
- Division of Child and Adolescent Neuropsychiatry, University Hospital of Siena, 53100 Siena, Italy
| | - Yuri Bozzi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068 Rovereto, Italy;
- CNR Institute of Neuroscience, 56124 Pisa, Italy
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Leontiadis LJ, Trompoukis G, Tsotsokou G, Miliou A, Felemegkas P, Papatheodoropoulos C. Rescue of sharp wave-ripples and prevention of network hyperexcitability in the ventral but not the dorsal hippocampus of a rat model of fragile X syndrome. Front Cell Neurosci 2023; 17:1296235. [PMID: 38107412 PMCID: PMC10722241 DOI: 10.3389/fncel.2023.1296235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder characterized by intellectual disability and is related to autism. FXS is caused by mutations of the fragile X messenger ribonucleoprotein 1 gene (Fmr1) and is associated with alterations in neuronal network excitability in several brain areas including hippocampus. The loss of fragile X protein affects brain oscillations, however, the effects of FXS on hippocampal sharp wave-ripples (SWRs), an endogenous hippocampal pattern contributing to memory consolidation have not been sufficiently clarified. In addition, it is still not known whether dorsal and ventral hippocampus are similarly affected by FXS. We used a Fmr1 knock-out (KO) rat model of FXS and electrophysiological recordings from the CA1 area of adult rat hippocampal slices to assess spontaneous and evoked neural activity. We find that SWRs and associated multiunit activity are affected in the dorsal but not the ventral KO hippocampus, while complex spike bursts remain normal in both segments of the KO hippocampus. Local network excitability increases in the dorsal KO hippocampus. Furthermore, specifically in the ventral hippocampus of KO rats we found an increased effectiveness of inhibition in suppressing excitation and an upregulation of α1GABAA receptor subtype. These changes in the ventral KO hippocampus are accompanied by a striking reduction in its susceptibility to induced epileptiform activity. We propose that the neuronal network specifically in the ventral segment of the hippocampus is reorganized in adult Fmr1-KO rats by means of balanced changes between excitability and inhibition to ensure normal generation of SWRs and preventing at the same time derailment of the neural activity toward hyperexcitability.
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Milla LA, Corral L, Rivera J, Zuñiga N, Pino G, Nunez-Parra A, Cea-Del Rio CA. Neurodevelopment and early pharmacological interventions in Fragile X Syndrome. Front Neurosci 2023; 17:1213410. [PMID: 37599992 PMCID: PMC10433175 DOI: 10.3389/fnins.2023.1213410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Fragile X Syndrome (FXS) is a neurodevelopmental disorder and the leading monogenic cause of autism and intellectual disability. For years, several efforts have been made to develop an effective therapeutic approach to phenotypically rescue patients from the disorder, with some even advancing to late phases of clinical trials. Unfortunately, none of these attempts have completely succeeded, bringing urgency to further expand and refocus research on FXS therapeutics. FXS arises at early stages of postnatal development due to the mutation and transcriptional silencing of the Fragile X Messenger Ribonucleoprotein 1 gene (FMR1) and consequent loss of the Fragile X Messenger Ribonucleoprotein (FMRP) expression. Importantly, FMRP expression is critical for the normal adult nervous system function, particularly during specific windows of embryogenic and early postnatal development. Cellular proliferation, migration, morphology, axonal guidance, synapse formation, and in general, neuronal network establishment and maturation are abnormally regulated in FXS, underlying the cognitive and behavioral phenotypes of the disorder. In this review, we highlight the relevance of therapeutically intervening during critical time points of development, such as early postnatal periods in infants and young children and discuss past and current clinical trials in FXS and their potential to specifically target those periods. We also discuss potential benefits, limitations, and disadvantages of these pharmacological tools based on preclinical and clinical research.
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Affiliation(s)
- Luis A. Milla
- Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Lucia Corral
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Jhanpool Rivera
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Nolberto Zuñiga
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Gabriela Pino
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Alexia Nunez-Parra
- Physiology Laboratory, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile
- Cell Physiology Center, Universidad de Chile, Santiago, Chile
| | - Christian A. Cea-Del Rio
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
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Martin GE, Lee M, Bicknell K, Goodkind A, Maltman N, Losh M. A longitudinal investigation of pragmatic language across contexts in autism and related neurodevelopmental conditions. Front Neurol 2023; 14:1155691. [PMID: 37545730 PMCID: PMC10402743 DOI: 10.3389/fneur.2023.1155691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/10/2023] [Indexed: 08/08/2023] Open
Abstract
Background Pragmatic language, or the use of language in social contexts, is a critical skill in daily life, supporting social interactions and the development of meaningful social relationships. Pragmatic language is universally impacted in autism spectrum disorder (ASD) and pragmatic deficits are also common in other neurodevelopmental conditions, particularly those related to ASD, such as fragile X syndrome (FXS). This study used a multi-method, longitudinal approach to characterize potentially unique pragmatic profiles across different neurodevelopmental disabilities, and across contexts that varied in degree of social demand. The utility of computational linguistic analyses, as an efficient tool for capturing pragmatic abilities, was also explored. Methods Pragmatic skills of boys with idiopathic ASD (ASD-O, n = 43), FXS with and without ASD (FXS-ASD, n = 57; FXS-O, n = 14), Down syndrome (DS, n = 22), and typical development (TD, n = 24) were compared using variables obtained from a standardized measure, narrative, and semi-naturalistic conversation at up to three time points. Results Pragmatic language was most significantly impacted among males with ASD-O and FXS-ASD across all three contexts, with more difficulties in the least structured context (conversation), and also some differences based on FXS comorbidity. Patterns of group differences were more nuanced for boys with FXS-O and DS, with context having less of an impact. Clinical groups demonstrated minimal changes in pragmatic skills with age, with some exceptions. Computational language measurement tools showed some utility for measuring pragmatic skills, but were not as successful as traditional methods at capturing differences between clinical groups. Conclusion Overlap and differences between ASD and other forms of neurodevelopmental disability in general, and between idiopathic and syndromic ASD in particular, have important implications for developing precisely tailored assessment and intervention approaches, consistent with a personalized medicine approach to clinical study and care in ASD.
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Affiliation(s)
- Gary E. Martin
- Department of Communication Sciences and Disorders, St. John’s University, Staten Island, NY, United States
| | - Michelle Lee
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
- Department of Child and Adolescent Psychiatry, Child Study Center, Hassenfeld Children’s Hospital at NYU Langone, New York, NY, United States
| | - Klinton Bicknell
- Department of Linguistics, Northwestern University, Evanston, IL, United States
- Duolingo, Pittsburgh, PA, United States
| | - Adam Goodkind
- Department of Linguistics, Northwestern University, Evanston, IL, United States
- Department of Communication Studies, Northwestern University, Evanston, IL, United States
| | - Nell Maltman
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
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Lacroix A, Proteau-Lemieux M, Côté S, Near J, Hui SC, Edden RA, Lippé S, Çaku A, Corbin F, Lepage JF. Multimodal assessment of the GABA system in patients with fragile-X syndrome and neurofibromatosis of type 1. Neurobiol Dis 2022; 174:105881. [DOI: 10.1016/j.nbd.2022.105881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/12/2022] [Accepted: 10/02/2022] [Indexed: 11/24/2022] Open
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From bench to bedside: The mGluR5 system in people with and without Autism Spectrum Disorder and animal model systems. Transl Psychiatry 2022; 12:395. [PMID: 36127322 PMCID: PMC9489881 DOI: 10.1038/s41398-022-02143-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/19/2022] [Accepted: 09/01/2022] [Indexed: 11/08/2022] Open
Abstract
The metabotropic glutamate receptor 5 (mGluR5) is a key regulator of excitatory (E) glutamate and inhibitory (I) γ-amino butyric acid (GABA) signalling in the brain. Despite the close functional ties between mGluR5 and E/I signalling, no-one has directly examined the relationship between mGluR5 and glutamate or GABA in vivo in the human brain of autistic individuals. We measured [18F] FPEB (18F-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile) binding in 15 adults (6 with Autism Spectrum Disorder) using two regions of interest, the left dorsomedial prefrontal cortex and a region primarily composed of left striatum and thalamus. These two regions were mapped out using MEGA-PRESS voxels and then superimposed on reconstructed PET images. This allowed for direct comparison between mGluR5, GABA + and Glx. To better understand the molecular underpinnings of our results we used an autoradiography study of mGluR5 in three mouse models associated with ASD: Cntnap2 knockout, Shank3 knockout, and 16p11.2 deletion. Autistic individuals had significantly higher [18F] FPEB binding (t (13) = -2.86, p = 0.047) in the left striatum/thalamus region of interest as compared to controls. Within this region, there was a strong negative correlation between GABA + and mGluR5 density across the entire cohort (Pearson's correlation: r (14) = -0.763, p = 0.002). Cntnap2 KO mice had significantly higher mGlu5 receptor binding in the striatum (caudate-putamen) as compared to wild-type (WT) mice (n = 15, p = 0.03). There were no differences in mGluR5 binding for mice with the Shank3 knockout or 16p11.2 deletion. Given that Cntnap2 is associated with a specific striatal deficit of parvalbumin positive GABA interneurons and 'autistic' features, our findings suggest that an increase in mGluR5 in ASD may relate to GABAergic interneuron abnormalities.
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Jeon SJ, Kwon H, Bae HJ, Gonzales EL, Kim J, Chung HJ, Kim DH, Ryu JH, Shin CY. Agmatine relieves behavioral impairments in Fragile X mice model. Neuropharmacology 2022; 219:109234. [PMID: 36057317 DOI: 10.1016/j.neuropharm.2022.109234] [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: 03/30/2022] [Revised: 07/25/2022] [Accepted: 08/21/2022] [Indexed: 10/31/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common heritable form of neurodevelopmental disorder, which is caused by the loss of fragile X mental retardation protein (FMRP) expression. Despite the unceasing efforts to develop therapeutic agents against FXS based on the pathophysiological changes observed in animal models of FXS and human patients, therapeutic candidates including mGluR signaling modulators have failed to provide sufficient effects. Based on the recent successful demonstration of an endogenous polyamine, agmatine, to improve the autism-like symptoms in the valproic acid animal model of autism, we investigated the effects of agmatine against FXS symptoms using Fmr1 knockout (KO) mice. METHODS We used male Fmr1 KO mice for behavioral tests such as marble burying, open-field test, memory tasks, social interaction tests and startle response to confirm the symptoms of FXS. We also checked the electrophysiological profile of neural activity in agmatine-treated Fmr1 KO mice. RESULTS Agmatine reversed the compulsion, learning and memory deficits, hyperactivity, aberrant social interaction, and communication deficit in Fmr1 KO mice while it normalized the aberrant LTP and LTD in the hippocampus. CONCLUSIONS The results highlight the potential of agmatine's novel disease-ameliorating effects in FXS, which warrants further studies to ascertain whether these findings translate into clinical effects in FXS patients.
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Affiliation(s)
- Se Jin Jeon
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea; Department of Integrative Biotechnology, College of Science and Technology, Sahmyook University, Seoul, 01795, Republic of Korea
| | - Huiyoung Kwon
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Ho Jung Bae
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Edson Luck Gonzales
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Junhyeong Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Hye Jin Chung
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Dong Hyun Kim
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - Jong Hoon Ryu
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Chan Young Shin
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea.
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Braga MFM, Juranek J, Eiden LE, Li Z, Figueiredo TH, de Araujo Furtado M, Marini AM. GABAergic circuits of the basolateral amygdala and generation of anxiety after traumatic brain injury. Amino Acids 2022; 54:1229-1249. [PMID: 35798984 DOI: 10.1007/s00726-022-03184-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/20/2022] [Indexed: 11/25/2022]
Abstract
Traumatic brain injury (TBI) has reached epidemic proportions around the world and is a major public health concern in the United States. Approximately 2.8 million individuals sustain a traumatic brain injury and are treated in an Emergency Department yearly in the U.S., and about 50,000 of them die. Persistent symptoms develop in 10-15% of the cases including neuropsychiatric disorders. Anxiety is the second most common neuropsychiatric disorder that develops in those with persistent neuropsychiatric symptoms after TBI. Abnormalities or atrophy in the temporal lobe has been shown in the overwhelming number of TBI cases. The basolateral amygdala (BLA), a temporal lobe structure that consolidates, stores and generates fear and anxiety-based behavioral outputs, is a critical brain region in the anxiety circuitry. In this review, we sought to capture studies that characterized the relationship between human post-traumatic anxiety and structural/functional alterations in the amygdala. We compared the human findings with results obtained with a reproducible mild TBI animal model that demonstrated a direct relationship between the alterations in the BLA and an anxiety-like phenotype. From this analysis, both preliminary insights, and gaps in knowledge, have emerged which may open new directions for the development of rational and more efficacious treatments.
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Affiliation(s)
- Maria F M Braga
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Science School of Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Jenifer Juranek
- Department of Pediatric Surgery, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, TX, 77030, USA
| | - Lee E Eiden
- Section On Molecular Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, MD, 20814, USA
| | - Zheng Li
- Section On Synapse Development and Plasticity, National Institute of Mental Health, Intramural Research Program, Bethesda, MD, 20814, USA
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Science School of Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Marcio de Araujo Furtado
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Science School of Medicine, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Ann M Marini
- Department of Neurology and Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
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Volkova YA, Rassokhina IV, Kondrakhin EA, Rossokhin AV, Kolbaev SN, Tihonova TB, Kh. Dzhafarov M, Schetinina MA, Chernoburova EI, Vasileva EV, Dmitrenok AS, Kovalev GI, Sharonova IN, Zavarzin IV. Synthesis and Evaluation of Avermectin–Imidazo[1,2-a]pyridine Hybrids as Potent GABAA Receptor Modulators. Bioorg Chem 2022; 127:105904. [DOI: 10.1016/j.bioorg.2022.105904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 05/18/2022] [Accepted: 05/21/2022] [Indexed: 01/08/2023]
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Keeping Excitation-Inhibition Ratio in Balance. Int J Mol Sci 2022; 23:ijms23105746. [PMID: 35628556 PMCID: PMC9145842 DOI: 10.3390/ijms23105746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/17/2022] [Accepted: 05/20/2022] [Indexed: 11/17/2022] Open
Abstract
Unrelated genetic mutations can lead to convergent manifestations of neurological disorders with similar behavioral phenotypes. Experimental data frequently show a lack of dramatic changes in neuroanatomy, indicating that the key cause of symptoms might arise from impairment in the communication between neurons. A transient imbalance between excitatory (glutamatergic) and inhibitory (GABAergic) synaptic transmission (the E/I balance) during early development is generally considered to underlie the development of several neurological disorders in adults. However, the E/I ratio is a multidimensional variable. Synaptic contacts are highly dynamic and the actual strength of synaptic projections is determined from the balance between synaptogenesis and synaptic elimination. During development, relatively slow postsynaptic receptors are replaced by fast ones that allow for fast stimulus-locked excitation/inhibition. Using the binomial model of synaptic transmission allows for the reassessing of experimental data from different mouse models, showing that a transient E/I shift is frequently counterbalanced by additional pre- and/or postsynaptic changes. Such changes—for instance, the slowing down of postsynaptic currents by means of immature postsynaptic receptors—stabilize the average synaptic strength, but impair the timing of information flow. Compensatory processes and/or astrocytic signaling may represent possible targets for medical treatments of different disorders directed to rescue the proper information processing.
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Curnow E, Wang Y. New Animal Models for Understanding FMRP Functions and FXS Pathology. Cells 2022; 11:1628. [PMID: 35626665 PMCID: PMC9140010 DOI: 10.3390/cells11101628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/03/2022] [Accepted: 05/09/2022] [Indexed: 11/16/2022] Open
Abstract
Fragile X encompasses a range of genetic conditions, all of which result as a function of changes within the FMR1 gene and abnormal production and/or expression of the FMR1 gene products. Individuals with Fragile X syndrome (FXS), the most common heritable form of intellectual disability, have a full-mutation sequence (>200 CGG repeats) which brings about transcriptional silencing of FMR1 and loss of FMR protein (FMRP). Despite considerable progress in our understanding of FXS, safe, effective, and reliable treatments that either prevent or reduce the severity of the FXS phenotype have not been approved. While current FXS animal models contribute their own unique understanding to the molecular, cellular, physiological, and behavioral deficits associated with FXS, no single animal model is able to fully recreate the FXS phenotype. This review will describe the status and rationale in the development, validation, and utility of three emerging animal model systems for FXS, namely the nonhuman primate (NHP), Mongolian gerbil, and chicken. These developing animal models will provide a sophisticated resource in which the deficits in complex functions of perception, action, and cognition in the human disorder are accurately reflected and aid in the successful translation of novel therapeutics and interventions to the clinic setting.
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Affiliation(s)
- Eliza Curnow
- REI Division, Department of ObGyn, University of Washington, Seattle, WA 98195, USA
- Washington National Primate Research Center, University of Washington, Seattle, WA 98195, USA
| | - Yuan Wang
- Program in Neuroscience, Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
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Al Dera H. Cellular and molecular mechanisms underlying autism spectrum disorders and associated comorbidities: A pathophysiological review. Biomed Pharmacother 2022; 148:112688. [PMID: 35149383 DOI: 10.1016/j.biopha.2022.112688] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/25/2022] [Accepted: 02/01/2022] [Indexed: 12/31/2022] Open
Abstract
Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders that develop in early life due to interaction between several genetic and environmental factors and lead to alterations in brain function and structure. During the last decades, several mechanisms have been placed to explain the pathogenesis of autism. Unfortunately, these are reported in several studies and reviews which make it difficult to follow by the reader. In addition, some recent molecular mechanisms related to ASD have been unrevealed. This paper revises and highlights the major common molecular mechanisms responsible for the clinical symptoms seen in people with ASD, including the roles of common genetic factors and disorders, neuroinflammation, GABAergic signaling, and alterations in Ca+2 signaling. Besides, it covers the major molecular mechanisms and signaling pathways involved in initiating the epileptic seizure, including the alterations in the GABAergic and glutamate signaling, vitamin and mineral deficiency, disorders of metabolism, and autoimmunity. Finally, this review also discusses sleep disorder patterns and the molecular mechanisms underlying them.
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Affiliation(s)
- Hussain Al Dera
- Department of Basic Medical Sciences, College of Medicine at King Saud, Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia.
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Verma V, Kumar MJV, Sharma K, Rajaram S, Muddashetty R, Manjithaya R, Behnisch T, Clement JP. Pharmacological intervention in young adolescents rescues synaptic physiology and behavioural deficits in Syngap1 +/- mice. Exp Brain Res 2021; 240:289-309. [PMID: 34739555 DOI: 10.1007/s00221-021-06254-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 10/21/2021] [Indexed: 01/04/2023]
Abstract
Haploinsufficiency in SYNGAP1 is implicated in intellectual disability (ID) and autism spectrum disorder (ASD) and affects the maturation of dendritic spines. The abnormal spine development has been suggested to cause a disbalance of excitatory and inhibitory (E/I) neurotransmission at distinct developmental periods. In addition, E/I imbalances in Syngap1+/- mice might be due to abnormalities in K+-Cl- co-transporter function (NKCC1, KCC2), in a maner similar to the murine models of Fragile-X and Rett syndromes. To study whether an altered intracellular chloride ion concentration represents an underlying mechanism of modified function of GABAergic synapses in Dentate Gyrus Granule Cells of Syngap1+/- recordings were performed at different developmental stages of the mice. We observed depolarised neurons at P14-15 as illustrated by decreased Cl- reversal potential in Syngap1+/- mice. The KCC2 expression was decreased compared to Wild-type (WT) mice at P14-15. The GSK-3β inhibitor, 6-bromoindirubin-3'-oxime (6BIO) that crosses the blood-brain barrier, was tested to restore the function of GABAergic synapses. We discovered that the intraperitoneal administration of 6BIO during the critical period or young adolescents [P30 to P80 (4-week to 10-week)] normalised an altered E/I balance, the deficits of synaptic plasticity, and behavioural performance like social novelty, anxiety, and memory of the Syngap1+/- mice. In summary, altered GABAergic function in Syngap1+/- mice is due to reduced KCC2 expression leading to an increase in the intracellular chloride concentration that can be counteracted by the 6BIO, which restored cognitive, emotional, and social symptoms by pharmacological intervention, particularly in adulthood.
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Affiliation(s)
- Vijaya Verma
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - M J Vijay Kumar
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Kavita Sharma
- International Centre for Material Sciences, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Sridhar Rajaram
- International Centre for Material Sciences, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Ravi Muddashetty
- Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, 560065, India
| | - Ravi Manjithaya
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.,Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
| | - Thomas Behnisch
- Institutes of Brain Sciences, Fudan University, Shanghai, 200032, China
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.
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Moskalyuk A, Van De Vijver S, Verstraelen P, De Vos WH, Kooy RF, Giugliano M. Single-Cell and Neuronal Network Alterations in an In Vitro Model of Fragile X Syndrome. Cereb Cortex 2021; 30:31-46. [PMID: 30958540 DOI: 10.1093/cercor/bhz068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Fragile X mental retardation protein (FMRP) is involved in many cellular processes and it regulates synaptic and network development in neurons. Its absence is known to lead to intellectual disability, with a wide range of comorbidities including autism. Over the past decades, FMRP research focused on abnormalities both in glutamatergic and GABAergic signaling, and an altered balance between excitation and inhibition has been hypothesized to underlie the clinical consequences of absence of the protein. Using Fmrp knockout mice, we studied an in vitro model of cortical microcircuitry and observed that the loss of FMRP largely affected the electrophysiological correlates of network development and maturation but caused less alterations in single-cell phenotypes. The loss of FMRP also caused a structural increase in the number of excitatory synaptic terminals. Using a mathematical model, we demonstrated that the combination of an increased excitation and reduced inhibition describes best our experimental observations during the ex vivo formation of the network connections.
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Affiliation(s)
- Anastasiya Moskalyuk
- Molecular, Cellular, and Network Excitability Lab, University of Antwerp, Wilrijk, Flanders, Belgium
| | - Sebastiaan Van De Vijver
- Molecular, Cellular, and Network Excitability Lab, University of Antwerp, Wilrijk, Flanders, Belgium
| | - Peter Verstraelen
- Laboratory of Cell Biology and Histology, University of Antwerp, Wilrijk, Flanders, Belgium
| | - Winnok H De Vos
- Laboratory of Cell Biology and Histology, University of Antwerp, Wilrijk, Flanders, Belgium
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Edegem, Flanders, Belgium
| | - Michele Giugliano
- Molecular, Cellular, and Network Excitability Lab, University of Antwerp, Wilrijk, Flanders, Belgium.,International School for Advanced Studies (SISSA), Trieste, Italy
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15
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Schieweck R, Ninkovic J, Kiebler MA. RNA-binding proteins balance brain function in health and disease. Physiol Rev 2020; 101:1309-1370. [PMID: 33000986 DOI: 10.1152/physrev.00047.2019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional gene expression including splicing, RNA transport, translation, and RNA decay provides an important regulatory layer in many if not all molecular pathways. Research in the last decades has positioned RNA-binding proteins (RBPs) right in the center of posttranscriptional gene regulation. Here, we propose interdependent networks of RBPs to regulate complex pathways within the central nervous system (CNS). These are involved in multiple aspects of neuronal development and functioning, including higher cognition. Therefore, it is not sufficient to unravel the individual contribution of a single RBP and its consequences but rather to study and understand the tight interplay between different RBPs. In this review, we summarize recent findings in the field of RBP biology and discuss the complex interplay between different RBPs. Second, we emphasize the underlying dynamics within an RBP network and how this might regulate key processes such as neurogenesis, synaptic transmission, and synaptic plasticity. Importantly, we envision that dysfunction of specific RBPs could lead to perturbation within the RBP network. This would have direct and indirect (compensatory) effects in mRNA binding and translational control leading to global changes in cellular expression programs in general and in synaptic plasticity in particular. Therefore, we focus on RBP dysfunction and how this might cause neuropsychiatric and neurodegenerative disorders. Based on recent findings, we propose that alterations in the entire regulatory RBP network might account for phenotypic dysfunctions observed in complex diseases including neurodegeneration, epilepsy, and autism spectrum disorders.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Jovica Ninkovic
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
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16
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Mariano V, Achsel T, Bagni C, Kanellopoulos AK. Modelling Learning and Memory in Drosophila to Understand Intellectual Disabilities. Neuroscience 2020; 445:12-30. [PMID: 32730949 DOI: 10.1016/j.neuroscience.2020.07.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 12/24/2022]
Abstract
Neurodevelopmental disorders (NDDs) include a large number of conditions such as Fragile X syndrome, autism spectrum disorders and Down syndrome, among others. They are characterized by limitations in adaptive and social behaviors, as well as intellectual disability (ID). Whole-exome and whole-genome sequencing studies have highlighted a large number of NDD/ID risk genes. To dissect the genetic causes and underlying biological pathways, in vivo experimental validation of the effects of these mutations is needed. The fruit fly, Drosophila melanogaster, is an ideal model to study NDDs, with highly tractable genetics, combined with simple behavioral and circuit assays, permitting rapid medium-throughput screening of NDD/ID risk genes. Here, we review studies where the use of well-established assays to study mechanisms of learning and memory in Drosophila has permitted insights into molecular mechanisms underlying IDs. We discuss how technologies in the fly model, combined with a high degree of molecular and physiological conservation between flies and mammals, highlight the Drosophila system as an ideal model to study neurodevelopmental disorders, from genetics to behavior.
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Affiliation(s)
- Vittoria Mariano
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne 1005, Switzerland; Department of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Tilmann Achsel
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne 1005, Switzerland
| | - Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne 1005, Switzerland; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome 00133, Italy.
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17
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Telias M. Pharmacological Treatments for Fragile X Syndrome Based on Synaptic Dysfunction. Curr Pharm Des 2020; 25:4394-4404. [PMID: 31682210 DOI: 10.2174/1381612825666191102165206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 10/31/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common form of monogenic hereditary cognitive impairment, including intellectual disability, autism, hyperactivity, and epilepsy. METHODS This article reviews the literature pertaining to the role of synaptic dysfunction in FXS. RESULTS In FXS, synaptic dysfunction alters the excitation-inhibition ratio, dysregulating molecular and cellular processes underlying cognition, learning, memory, and social behavior. Decades of research have yielded important hypotheses that could explain, at least in part, the development of these neurological disorders in FXS patients. However, the main goal of translating lab research in animal models to pharmacological treatments in the clinic has been so far largely unsuccessful, leaving FXS a still incurable disease. CONCLUSION In this concise review, we summarize and analyze the main hypotheses proposed to explain synaptic dysregulation in FXS, by reviewing the scientific evidence that led to pharmaceutical clinical trials and their outcome.
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Affiliation(s)
- Michael Telias
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
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18
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Van der Aa N, Kooy RF. GABAergic abnormalities in the fragile X syndrome. Eur J Paediatr Neurol 2020; 24:100-104. [PMID: 31926845 DOI: 10.1016/j.ejpn.2019.12.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/18/2019] [Indexed: 12/24/2022]
Abstract
Many pathways have been involved in pathophysiology of the fragile X syndrome, one of the more frequent genetic causes of intellectual disability and autism. This review highlights the recent insights in the role the abnormalities in the GABAergic system play in the disorder. Since the initial observations showed that the expression of specific subunits of the GABA(A) receptor were underexpressed in the fragile X knockout mouse model more than a decade ago, evidence has accumulated that the expression of approximately half of the GABAergic system is compromised in multiple species, including in fragile X patients. Functional consequences of the GABAergic deficiencies could be measured using whole-cell voltage clamp recordings. Pharmalogical treatment with agonist of the receptor was been able to restore several behavioral deficits in the fragile X mouse model, including seizures, marble burying and, in part, prepulse inhibition. Trials in patients with the same agonist have demonstrated encouraging post-hoc results in the most severely affected patients, although no effect could be demonstrated in the patient group as a whole. In conclusion, there can be little doubt that the GABAergic system is compromised in the fragile X syndrome and that these abnormalities contribute to the clinical abnormalities observed. However, at the moment the difference in treatment effectiveness of agonist of the receptor in animal models as opposed to in patients remains unexplained.
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Affiliation(s)
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
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19
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Cogram P, Deacon RMJ, Warner-Schmidt JL, von Schimmelmann MJ, Abrahams BS, During MJ. Gaboxadol Normalizes Behavioral Abnormalities in a Mouse Model of Fragile X Syndrome. Front Behav Neurosci 2019; 13:141. [PMID: 31293404 PMCID: PMC6603241 DOI: 10.3389/fnbeh.2019.00141] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/07/2019] [Indexed: 12/11/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited form of intellectual disability and autism. FXS is also accompanied by attention problems, hyperactivity, anxiety, aggression, poor sleep, repetitive behaviors, and self-injury. Recent work supports the role of γ-aminobutyric-acid (GABA), the primary inhibitory neurotransmitter in the brain, in mediating symptoms of FXS. Deficits in GABA machinery have been observed in a mouse model of FXS, including a loss of tonic inhibition in the amygdala, which is mediated by extrasynaptic GABAA receptors. Humans with FXS also show reduced GABAA receptor availability. Here, we sought to evaluate the potential of gaboxadol (also called OV101 and THIP), a selective and potent agonist for delta-subunit-containing extrasynaptic GABAA receptors (dSEGA), as a therapeutic agent for FXS by assessing its ability to normalize aberrant behaviors in a relatively uncharacterized mouse model of FXS (Fmr1 KO2 mice). Four behavioral domains (hyperactivity, anxiety, aggression, and repetitive behaviors) were probed using a battery of behavioral assays. The results showed that Fmr1 KO2 mice were hyperactive, had abnormal anxiety-like behavior, were more irritable and aggressive, and had an increased frequency of repetitive behaviors compared to wild-type (WT) littermates, which are all behavioral deficits reminiscent of individuals with FXS. Treatment with gaboxadol normalized all of the aberrant behaviors observed in Fmr1 KO2 mice back to WT levels, providing evidence of its potential benefit for treating FXS. We show that the potentiation of extrasynaptic GABA receptors alone, by gaboxadol, is sufficient to normalize numerous behavioral deficits in the FXS model using endpoints that are directly translatable to the clinical presentation of FXS. Taken together, these data support the future evaluation of gaboxadol in individuals with FXS, particularly with regard to symptoms of hyperactivity, anxiety, irritability, aggression, and repetitive behaviors.
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Affiliation(s)
- Patricia Cogram
- FRAXA-DVI, FRAXA Research Foundation, Boston, MA, United States.,Centre for Systems Biotechnology, Biomedicine Division, Fraunhofer-Gesellschaft, Santiago, Chile.,GEN.DDI Limited, London, United Kingdom.,Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago, Chile
| | - Robert M J Deacon
- FRAXA-DVI, FRAXA Research Foundation, Boston, MA, United States.,Centre for Systems Biotechnology, Biomedicine Division, Fraunhofer-Gesellschaft, Santiago, Chile.,GEN.DDI Limited, London, United Kingdom.,Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago, Chile
| | | | | | - Brett S Abrahams
- Ovid Therapeutics, New York, NY, United States.,Department of Genetics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Matthew J During
- Ovid Therapeutics, New York, NY, United States.,Department of Neurological Surgery and Molecular Virology, Immunology and Medical Genetics, Ohio State University College of Medicine, Columbus, OH, United States
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20
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Maussion G, Rocha C, Bernard G, Beitel LK, Durcan TM. Patient-Derived Stem Cells, Another in vitro Model, or the Missing Link Toward Novel Therapies for Autism Spectrum Disorders? Front Pediatr 2019; 7:225. [PMID: 31245336 PMCID: PMC6562499 DOI: 10.3389/fped.2019.00225] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 05/20/2019] [Indexed: 12/28/2022] Open
Abstract
Autism Spectrum Disorders (ASDs) is a multigenic and multifactorial neurodevelopmental group of disorders diagnosed in early childhood, leading to deficits in social interaction, verbal and non-verbal communication and characterized by restricted and repetitive behaviors and interests. To date, genetic, descriptive and mechanistic aspects of the ASDs have been investigated using mouse models and post-mortem brain tissue. More recently, the technology to generate stem cells from patients' samples has brought a new avenue for modeling ASD through 2D and 3D neuronal models that are derived from a patient's own cells, with the goal of building new therapeutic strategies for treating ASDs. This review analyses how studies performed on mouse models and human samples can complement each other, advancing our current knowledge into the pathophysiology of the ASDs. Regardless of the genetic and phenotypic heterogeneities of ASDs, convergent information regarding the molecular and cellular mechanisms involved in these disorders can be extracted from these models. Thus, considering the complexities of these disorders, patient-derived models have immense potential to elucidate molecular deregulations that contributed to the different autistic phenotypes. Through these direct investigations with the human in vitro models, they offer the potential for opening new therapeutic avenues that can be translated into the clinic.
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Affiliation(s)
- Gilles Maussion
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Cecilia Rocha
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada
- Division of Medical Genetics, Department of Internal Medicine, McGill University Health Center, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
- MyeliNeuroGene Laboratory, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Lenore K. Beitel
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Thomas M. Durcan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
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21
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Telias M. Molecular Mechanisms of Synaptic Dysregulation in Fragile X Syndrome and Autism Spectrum Disorders. Front Mol Neurosci 2019; 12:51. [PMID: 30899214 PMCID: PMC6417395 DOI: 10.3389/fnmol.2019.00051] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 02/12/2019] [Indexed: 12/21/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common form of monogenic hereditary cognitive impairment. FXS patient exhibit a high comorbidity rate with autism spectrum disorders (ASDs). This makes FXS a model disease for understanding how synaptic dysregulation alters neuronal excitability, learning and memory, social behavior, and more. Since 1991, with the discovery of fragile X mental retardation 1 (FMR1) as the sole gene that is mutated in FXS, thousands of studies into the function of the gene and its encoded protein FMR1 protein (FMRP), have been conducted, yielding important information regarding the pathophysiology of the disease, as well as insight into basic synaptic mechanisms that control neuronal networking and circuitry. Among the most important, are molecular mechanisms directly involved in plasticity, including glutamate and γ-aminobutyric acid (GABA) receptors, which can control synaptic transmission and signal transduction, including short- and long-term plasticity. More recently, several novel mechanisms involving growth factors, enzymatic cascades and transcription factors (TFs), have been proposed to have the potential of explaining some of the synaptic dysregulation in FXS. In this review article, I summarize the main mechanisms proposed to underlie synaptic disruption in FXS and ASDs. I focus on studies conducted on the Fmr1 knock-out (KO) mouse model and on FXS-human pluripotent stem cells (hPSCs), emphasizing the differences and even contradictions between mouse and human, whenever possible. As FXS and ASDs are both neurodevelopmental disorders that follow a specific time-course of disease progression, I highlight those studies focusing on the differential developmental regulation of synaptic abnormalities in these diseases.
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Affiliation(s)
- Michael Telias
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
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22
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Methyleugenol counteracts anorexigenic signals in association with GABAergic inhibition in the central amygdala. Neuropharmacology 2018; 141:331-342. [PMID: 30170083 DOI: 10.1016/j.neuropharm.2018.08.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 08/17/2018] [Accepted: 08/26/2018] [Indexed: 12/11/2022]
Abstract
Feeding can be inhibited by satiety, sickness, or food unpalatability. The central nucleus of the amygdala (CeA) has been considered the key region for processing multiple anorexigenic signals, although the detailed cellular and molecular mechanisms remain largely unclear. Here we identify that methyleugenol (ME), a novel agonist of A type ionotropic γ-aminobutyric acid receptors (GABAARs), significantly counteracts the anorexigenic effects caused by satiety or sickness in association with GABAergic inhibition in the CeA. Electrophysiologically, ME enhanced GABAergic transmission and repressed neuronal excitability of the CeA. Behaviorally, ME increased feeding but not affect locomotor activity and basal anxiety in naïve mice. Notably, both systemic and CeA-specific delivery of ME significantly rescued satiety- or sickness-induced inhibition of feeding. The effects of ME were mainly dependent on the GABAARs in the CeA. Indeed, viral-mediated, the CeA region-specific genetic knockdown of the γ2 subunit of GABAARs largely abolished the above pharmacological effects, while its re-expression in a subpopulation of GABAergic neurons in the CeA, that produce protein kinase C-δ (PKC-δ), recovered the effects of ME on anorexigenic signals. Taken together, these results reveal a novel molecular mechanism for counter-anorexigenic signals dependent on GABAergic inhibition in the CeA, suggesting the possibility of ME as a leading compound for anorexia treatment.
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23
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Zeidler S, Pop AS, Jaafar IA, de Boer H, Buijsen RAM, de Esch CEF, Nieuwenhuizen‐Bakker I, Hukema RK, Willemsen R. Paradoxical effect of baclofen on social behavior in the fragile X syndrome mouse model. Brain Behav 2018; 8:e00991. [PMID: 29785777 PMCID: PMC5991574 DOI: 10.1002/brb3.991] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/29/2018] [Accepted: 03/31/2018] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Fragile X syndrome (FXS) is a common monogenetic cause of intellectual disability, autism spectrum features, and a broad range of other psychiatric and medical problems. FXS is caused by the lack of the fragile X mental retardation protein (FMRP), a translational regulator of specific mRNAs at the postsynaptic compartment. The absence of FMRP leads to aberrant synaptic plasticity, which is believed to be caused by an imbalance in excitatory and inhibitory network functioning of the synapse. Evidence from studies in mice demonstrates that GABA, the major inhibitory neurotransmitter in the brain, and its receptors, is involved in the pathogenesis of FXS. Moreover, several FXS phenotypes, including social behavior deficits, could be corrected in Fmr1 KO mice after acute treatment with GABAB agonists. METHODS As FXS would probably require a lifelong treatment, we investigated the effect of chronic treatment with the GABAB agonist baclofen on social behavior in Fmr1 KO mice on two behavioral paradigms for social behavior: the automated tube test and the three-chamber sociability test. RESULTS Unexpectedly, chronic baclofen treatment resulted in worsening of the FXS phenotypes in these behavior tests. Strikingly, baclofen treatment also affected wild-type animals in both behavioral tests, inducing a phenotype similar to that of untreated Fmr1 KO mice. CONCLUSION Altogether, the disappointing results of recent clinical trials with the R-baclofen enantiomer arbaclofen and our current results indicate that baclofen should be reconsidered and further evaluated before its application in targeted treatment for FXS.
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Affiliation(s)
- Shimriet Zeidler
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Andreea S. Pop
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Israa A. Jaafar
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Helen de Boer
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Ronald A. M. Buijsen
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Celine E. F. de Esch
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | | | - Renate K. Hukema
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Rob Willemsen
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
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24
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Fink JJ, Levine ES. Uncovering True Cellular Phenotypes: Using Induced Pluripotent Stem Cell-Derived Neurons to Study Early Insults in Neurodevelopmental Disorders. Front Neurol 2018; 9:237. [PMID: 29713304 PMCID: PMC5911479 DOI: 10.3389/fneur.2018.00237] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/26/2018] [Indexed: 01/07/2023] Open
Abstract
Animal models of neurodevelopmental disorders have provided invaluable insights into the molecular-, cellular-, and circuit-level defects associated with a plethora of genetic disruptions. In many cases, these deficits have been linked to changes in disease-relevant behaviors, but very few of these findings have been translated to treatments for human disease. This may be due to significant species differences and the difficulty in modeling disorders that involve deletion or duplication of multiple genes. The identification of primary underlying pathophysiology in these models is confounded by the accumulation of secondary disease phenotypes in the mature nervous system, as well as potential compensatory mechanisms. The discovery of induced pluripotent stem cell technology now provides a tool to accurately model complex genetic neurogenetic disorders. Using this technique, patient-specific cell lines can be generated and differentiated into specific subtypes of neurons that can be used to identify primary cellular and molecular phenotypes. It is clear that impairments in synaptic structure and function are a common pathophysiology across neurodevelopmental disorders, and electrophysiological analysis at the earliest stages of neuronal development is critical for identifying changes in activity and excitability that can contribute to synaptic dysfunction and identify targets for disease-modifying therapies.
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Affiliation(s)
- James J Fink
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, United States
| | - Eric S Levine
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, United States
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25
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Rubinstein M, Patowary A, Stanaway IB, McCord E, Nesbitt RR, Archer M, Scheuer T, Nickerson D, Raskind WH, Wijsman EM, Bernier R, Catterall WA, Brkanac Z. Association of rare missense variants in the second intracellular loop of Na V1.7 sodium channels with familial autism. Mol Psychiatry 2018; 23:231-239. [PMID: 27956748 PMCID: PMC5468514 DOI: 10.1038/mp.2016.222] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 10/07/2016] [Accepted: 10/17/2016] [Indexed: 01/21/2023]
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder often accompanied by intellectual disability, language impairment and medical co-morbidities. The heritability of autism is high and multiple genes have been implicated as causal. However, most of these genes have been identified in de novo cases. To further the understanding of familial autism, we performed whole-exome sequencing on five families in which second- and third-degree relatives were affected. By focusing on novel and protein-altering variants, we identified a small set of candidate genes. Among these, a novel private missense C1143F variant in the second intracellular loop of the voltage-gated sodium channel NaV1.7, encoded by the SCN9A gene, was identified in one family. Through electrophysiological analysis, we show that NaV1.7C1143F exhibits partial loss-of-function effects, resulting in slower recovery from inactivation and decreased excitability in cultured cortical neurons. Furthermore, for the same intracellular loop of NaV1.7, we found an excess of rare variants in a case-control variant-burden study. Functional analysis of one of these variants, M932L/V991L, also demonstrated reduced firing in cortical neurons. However, although this variant is rare in Caucasians, it is frequent in Latino population, suggesting that genetic background can alter its effects on phenotype. Although the involvement of the SCN1A and SCN2A genes encoding NaV1.1 and NaV1.2 channels in de novo ASD has previously been demonstrated, our study indicates the involvement of inherited SCN9A variants and partial loss-of-function of NaV1.7 channels in the etiology of rare familial ASD.
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Affiliation(s)
- M Rubinstein
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - A Patowary
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - I B Stanaway
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - E McCord
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - R R Nesbitt
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - M Archer
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - T Scheuer
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - D Nickerson
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - W H Raskind
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA,Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
| | - E M Wijsman
- Department of Genome Sciences, University of Washington, Seattle, WA, USA,Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA,Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - R Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - W A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA, USA,Department of Pharmacology, University of Washington, Seattle, WA 98195, USA E-mail:
| | - Z Brkanac
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA,Department of Psychiatry and Behavioral Science, University of Washington, 1959N.E. Pacific Street, Room BB1526, Seattle, WA 98195-6560, USA. E-mail:
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26
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Castagnola S, Bardoni B, Maurin T. The Search for an Effective Therapy to Treat Fragile X Syndrome: Dream or Reality? Front Synaptic Neurosci 2017; 9:15. [PMID: 29163124 PMCID: PMC5681520 DOI: 10.3389/fnsyn.2017.00015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/16/2017] [Indexed: 12/22/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common form of intellectual disability and a primary cause of autism. It originates from the lack of the Fragile X Mental Retardation Protein (FMRP), which is an RNA-binding protein encoded by the Fragile X Mental Retardation Gene 1 (FMR1) gene. Multiple roles have been attributed to this protein, ranging from RNA transport (from the nucleus to the cytoplasm, but also along neurites) to translational control of mRNAs. Over the last 20 years many studies have found a large number of FMRP mRNA targets, but it is still not clear which are those playing a critical role in the etiology of FXS. So far, no therapy for FXS has been found, making the quest for novel targets of considerable importance. Several pharmacological approaches have been attempted, but, despite some promising preclinical results, no strategy gave successful outcomes, due either to the induction of major side effects or to the lack of improvement of the phenotypes. However, these studies suggested that, in order to measure the effectiveness of a specific treatment, trials should be redesigned and new endpoints defined in FXS patients. Nevertheless, the search for new therapeutic targets for FXS is very active. In this context, the advances in animal modeling, coupled with better understanding of neurobiology and physiopathology of FXS, are of crucial importance in developing new selected treatments. Here, we discuss the pathways that were recently linked to the physiopathology of FXS (mGluR, GABAR, insulin, Insulin-like Growth Factor 1 (IGF-1), MPP-9, serotonin, oxytocin and endocannabinoid signaling) and that suggest new approaches to find an effective therapy for this disorder. Our goal with this review article is to summarize some recent relevant findings on FXS treatment strategies in order to have a clearer view of the different pathways analyzed to date emphasizing those shared with other synaptic disorders.
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Affiliation(s)
- Sara Castagnola
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
| | - Barbara Bardoni
- Université Côte d'Azur, INSERM, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
| | - Thomas Maurin
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
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Inhibitors of Histone Deacetylases Are Weak Activators of the FMR1 Gene in Fragile X Syndrome Cell Lines. BIOMED RESEARCH INTERNATIONAL 2017; 2017:3582601. [PMID: 29209628 PMCID: PMC5676349 DOI: 10.1155/2017/3582601] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/18/2017] [Accepted: 09/28/2017] [Indexed: 01/19/2023]
Abstract
Fragile X syndrome is the most common cause of inherited intellectual disability in humans. It is a result of CGG repeat expansion in the 5' untranslated region (5' UTR) of the FMR1 gene. This gene encodes the FMRP protein that is involved in neuronal development. Repeat expansion leads to heterochromatinization of the promoter, gene silencing, and the subsequent absence of FMRP. To date, there is no specific therapy for the syndrome. All treatments in clinic practice provide symptomatic therapy. The development of drug therapy for Fragile X syndrome treatment is connected with the search for inhibitors of enzymes that are responsible for heterochromatinization. Here, we report a weak transcriptional activity of the FMR1 gene and the absence of FMRP protein after Fragile X syndrome cell lines treatment with two FDA approved inhibitors of histone deacetylases, romidepsin and vorinostat. We demonstrate that romidepsin, an inhibitor of class I histone deacetylases, does not activate FMR1 expression in patient cell cultures, whereas vorinostat, an inhibitor of classes I and II histone deacetylases, activates a low level of FMR1 expression in some patient cell lines.
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28
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Abstract
Fragile X syndrome (FXS) is the leading inherited form of intellectual disability and autism spectrum disorder, and patients can present with severe behavioural alterations, including hyperactivity, impulsivity and anxiety, in addition to poor language development and seizures. FXS is a trinucleotide repeat disorder, in which >200 repeats of the CGG motif in FMR1 leads to silencing of the gene and the consequent loss of its product, fragile X mental retardation 1 protein (FMRP). FMRP has a central role in gene expression and regulates the translation of potentially hundreds of mRNAs, many of which are involved in the development and maintenance of neuronal synaptic connections. Indeed, disturbances in neuroplasticity is a key finding in FXS animal models, and an imbalance in inhibitory and excitatory neuronal circuits is believed to underlie many of the clinical manifestations of this disorder. Our knowledge of the proteins that are regulated by FMRP is rapidly growing, and this has led to the identification of multiple targets for therapeutic intervention, some of which have already moved into clinical trials or clinical practice.
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Ligsay A, Van Dijck A, Nguyen DV, Lozano R, Chen Y, Bickel ES, Hessl D, Schneider A, Angkustsiri K, Tassone F, Ceulemans B, Kooy RF, Hagerman RJ. A randomized double-blind, placebo-controlled trial of ganaxolone in children and adolescents with fragile X syndrome. J Neurodev Disord 2017; 9:26. [PMID: 28764646 PMCID: PMC5540519 DOI: 10.1186/s11689-017-9207-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 06/01/2017] [Indexed: 12/14/2022] Open
Abstract
Background Gamma-aminobutyric acid (GABA) system deficits are integral to the pathophysiologic development of fragile X syndrome (FXS). Ganaxolone, a GABAA receptor positive allosteric modulator, is hypothesized to improve symptoms such as anxiety, hyperactivity, and attention deficits in children with FXS. Methods This study was a randomized, double-blind, placebo-controlled, crossover trial of ganaxolone in children with FXS, aged 6–17 years. Results Sixty-one participants were assessed for eligibility, and 59 were randomized to the study. Fifty-five participants completed at least the first arm and were included in the intention-to-treat analysis; 51 participants completed both treatment arms. There were no statistically significant improvements observed on the primary outcome measure (Clinical Global Impression-Improvement), the key secondary outcome measure (Pediatric Anxiety Rating Scale-R), or any other secondary outcome measures in the overall study population. However, post-hoc analyses revealed positive trends in areas of anxiety, attention, and hyperactivity in participants with higher baseline anxiety and low full-scale IQ scores. No serious adverse events (AEs) occurred, although there was a significant increase in the frequency and severity of AEs related to ganaxolone compared to placebo. Conclusions While ganaxolone was found to be safe, there were no significant improvements in the outcome measures in the overall study population. However, ganaxolone in subgroups of children with FXS, including those with higher anxiety or lower cognitive abilities, might have beneficial effects. Trial registration ClinicalTrials.gov, NCT01725152
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Affiliation(s)
- Andrew Ligsay
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,University of California, Davis School of Medicine, Sacramento, CA, USA
| | - Anke Van Dijck
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.,Department of Neurology-Pediatric Neurology, University Hospital Antwerp, University of Antwerp, Antwerp, Belgium
| | - Danh V Nguyen
- Department of Medicine, University of California, Irvine School of Medicine, Orange, California, USA.,Biostatistics Institute for Clinical and Translational Science, University of California, Irvine, California, USA
| | - Reymundo Lozano
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,Seaver Autism Center for Research and Treatment, Department of Genetics and Genomic Sciences, Psychiatry, and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA, USA
| | - Yanjun Chen
- Biostatistics Institute for Clinical and Translational Science, University of California, Irvine, California, USA
| | - Erika S Bickel
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA, USA
| | - David Hessl
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,Department of Psychiatry and Behavioral Sciences, University of California, Davis Medical Center, Sacramento, CA, USA
| | - Andrea Schneider
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA, USA
| | - Kathleen Angkustsiri
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA, USA
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA.,Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - Berten Ceulemans
- Department of Neurology-Pediatric Neurology, University Hospital Antwerp, University of Antwerp, Antwerp, Belgium
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA, 95817, USA. .,Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA, USA.
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Berry-Kravis E, Hagerman R, Visootsak J, Budimirovic D, Kaufmann WE, Cherubini M, Zarevics P, Walton-Bowen K, Wang P, Bear MF, Carpenter RL. Arbaclofen in fragile X syndrome: results of phase 3 trials. J Neurodev Disord 2017; 9:3. [PMID: 28616094 PMCID: PMC5467054 DOI: 10.1186/s11689-016-9181-6] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 12/07/2016] [Indexed: 12/18/2022] Open
Abstract
Background Arbaclofen improved multiple abnormal phenotypes in animal models of fragile X syndrome (FXS) and showed promising results in a phase 2 clinical study. The objective of the study is to determine safety and efficacy of arbaclofen for social avoidance in FXS. Methods Two phase 3 placebo-controlled trials were conducted, a flexible dose trial in subjects age 12–50 (209FX301, adolescent/adult study) and a fixed dose trial in subjects age 5–11 (209FX302, child study). The primary endpoint for both trials was the Social Avoidance subscale of the Aberrant Behavior Checklist-Community Edition, FXS-specific (ABC-CFX). Secondary outcomes included other ABC-CFX subscale scores, Clinical Global Impression-Improvement (CGI-I), Clinical Global Impression-Severity (CGI-S), and Vineland Adaptive Behavior Scales, Second Edition (Vineland-II) Socialization domain score. Results A total 119 of 125 randomized subjects completed the adolescent/adult study (n = 57 arbaclofen, 62 placebo) and 159/172 completed the child study (arbaclofen 5 BID n = 38; 10 BID n = 39; 10 TID n = 38; placebo n = 44). There were no serious adverse events (AEs); the most common AEs included somatic (headache, vomiting, nausea), neurobehavioral (irritability/agitation, anxiety, hyperactivity), decreased appetite, and infectious conditions, many of which were also common on placebo. In the combined studies, there were 13 discontinuations (n = 12 arbaclofen, 1 placebo) due to AEs (all neurobehavioral). The adolescent/adult study did not show benefit for arbaclofen over placebo for any measure. In the child study, the highest dose group showed benefit over placebo on the ABC-CFX Irritability subscale (p = 0.03) and Parenting Stress Index (PSI, p = 0.03) and trends toward benefit on the ABC-CFX Social Avoidance and Hyperactivity subscales (both p < 0.1) and CGI-I (p = 0.119). Effect size in the highest dose group was similar to effect sizes for FDA-approved serotonin reuptake inhibitors (SSRIs). Conclusions Arbaclofen did not meet the primary outcome of improved social avoidance in FXS in either study. Data from secondary measures in the child study suggests younger patients may derive benefit, but additional studies with a larger cohort on higher doses would be required to confirm this finding. The reported studies illustrate the challenges but represent a significant step forward in translating targeted treatments from preclinical models to clinical trials in humans with FXS.
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Affiliation(s)
- Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, Biochemistry, Rush University Medical Center, 1725 West Harrison, Suite 718, Chicago, IL 60612 USA
| | - Randi Hagerman
- MIND Institute and Department of Pediatrics, University of California Davis Medical Center, 2825 50th Street, Sacramento, CA 95817 USA
| | - Jeannie Visootsak
- Department of Human Genetics, Emory University, 2165 N. Decatur Road, Decatur, GA 30033 USA
| | - Dejan Budimirovic
- Departments of Psychiatry &Behavioral Sciences, Kennedy Krieger Institute, the Johns Hopkins Medical Institutions, 716 N. Broadway, Room 246, Baltimore, MD 21205 USA
| | - Walter E Kaufmann
- Department of Neurology, Boston Children's Hospital, Boston, MA 02115 and Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Maryann Cherubini
- Seaside Therapeutics Inc, 124 Washington Street, Suite 101, Foxboro, MA 02035, USA
| | - Peter Zarevics
- Seaside Therapeutics Inc, 124 Washington Street, Suite 101, Foxboro, MA 02035, USA
| | - Karen Walton-Bowen
- Simons Foundation Autism Research Initiative, 160 Fifth Avenue, 7th Floor, New York, NY 10010, USA
| | - Paul Wang
- Autism Speaks, 1 East 33rd Street, 4th Floor, New York, NY 10016, USA
| | - Mark F Bear
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, 43 Vassar Street, 46-3301, Cambridge, MA 02139, USA
| | - Randall L Carpenter
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, 43 Vassar Street, 46-3301, Cambridge, MA 02139, USA.,Rett Syndrome Research Trust, 67 Under Cliff Rd, Trumbull, CT 06611, USA
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31
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Pugin A, Faundes V, Santa María L, Curotto B, Aliaga S, Salas I, Soto P, Bravo P, Peña M, Alliende M. Clinical, molecular, and pharmacological aspects of FMR1 -related disorders. NEUROLOGÍA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.nrleng.2014.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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32
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Kang JY, Chadchankar J, Vien TN, Mighdoll MI, Hyde TM, Mather RJ, Deeb TZ, Pangalos MN, Brandon NJ, Dunlop J, Moss SJ. Deficits in the activity of presynaptic γ-aminobutyric acid type B receptors contribute to altered neuronal excitability in fragile X syndrome. J Biol Chem 2017; 292:6621-6632. [PMID: 28213518 PMCID: PMC5399111 DOI: 10.1074/jbc.m116.772541] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 02/07/2017] [Indexed: 11/06/2022] Open
Abstract
The behavioral and anatomical deficits seen in fragile X syndrome (FXS) are widely believed to result from imbalances in the relative strengths of excitatory and inhibitory neurotransmission. Although modified neuronal excitability is thought to be of significance, the contribution that alterations in GABAergic inhibition play in the pathophysiology of FXS are ill defined. Slow sustained neuronal inhibition is mediated by γ-aminobutyric acid type B (GABAB) receptors, which are heterodimeric G-protein-coupled receptors constructed from R1a and R2 or R1b and R2 subunits. Via the activation of Gi/o, they limit cAMP accumulation, diminish neurotransmitter release, and induce neuronal hyperpolarization. Here we reveal that selective deficits in R1a subunit expression are seen in Fmr1 knock-out mice (KO) mice, a widely used animal model of FXS, but the levels of the respective mRNAs were unaffected. Similar trends of R1a expression were seen in a subset of FXS patients. GABAB receptors (GABABRs) exert powerful pre- and postsynaptic inhibitory effects on neurotransmission. R1a-containing GABABRs are believed to mediate presynaptic inhibition in principal neurons. In accordance with this result, deficits in the ability of GABABRs to suppress glutamate release were seen in Fmr1-KO mice. In contrast, the ability of GABABRs to suppress GABA release and induce postsynaptic hyperpolarization was unaffected. Significantly, this deficit contributes to the pathophysiology of FXS as the GABABR agonist (R)-baclofen rescued the imbalances between excitatory and inhibitory neurotransmission evident in Fmr1-KO mice. Collectively, our results provided evidence that selective deficits in the activity of presynaptic GABABRs contribute to the pathophysiology of FXS.
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Affiliation(s)
- Ji-Yong Kang
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Jayashree Chadchankar
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Thuy N Vien
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | - Thomas M Hyde
- the Lieber Institute for Brain Development and
- Departments of Neurology and Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Robert J Mather
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
| | - Tarek Z Deeb
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Menelas N Pangalos
- Innovative Medicines and Early Development, AstraZeneca, Melbourn Science Park, Cambridge Road, Royston Herts SG8 6EE, United Kingdom, and
| | - Nicholas J Brandon
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
| | - John Dunlop
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
| | - Stephen J Moss
- From the AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111,
- Neuroscience, Innovative Medicines and Early Development, AstraZeneca, Waltham, Massachusetts 02451
- the Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E 6BT, United Kingdom
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Sabanov V, Braat S, D'Andrea L, Willemsen R, Zeidler S, Rooms L, Bagni C, Kooy RF, Balschun D. Impaired GABAergic inhibition in the hippocampus of Fmr1 knockout mice. Neuropharmacology 2016; 116:71-81. [PMID: 28012946 DOI: 10.1016/j.neuropharm.2016.12.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 11/30/2016] [Accepted: 12/12/2016] [Indexed: 01/24/2023]
Abstract
Many clinical and molecular features of the fragile X syndrome, a common form of intellectual disability and autism, can be modeled by deletion of the Fmr1 protein (Fmrp) in mice. Previous studies showed a decreased expression of several components of the GABAergic system in Fmr1 knockout mice. Here, we used this mouse model to investigate the functional consequences of Fmrp deletion on hippocampal GABAergic inhibition in the CA1-region of the hippocampus. Whole-cell patch-clamp recordings demonstrated a significantly reduced amplitude of evoked inhibitory postsynaptic currents (eIPSCs) and a decrease in the amplitude and frequency of spontaneous IPSCs. In addition, miniature IPSCs were reduced in amplitude and frequency and decayed significantly slower than mIPSCs in controls. Quantitative real-time PCR revealed a significantly lower expression of α2, β1 and δ GABAA receptor subunits in the hippocampus of the juvenile mice (P22) compared to wild-type littermates. Correspondingly, we found also at the protein level reduced amounts of α2, β1 and δ subunits in Fmr1 knockout mice. Overall, these results demonstrate that the reduction in several components of the GABAergic system is already present at young age and that this reduction results in measurable abnormalities on GABAA receptor-mediated phasic inhibition. These abnormalities might contribute to the behavioral and cognitive deficits of this fragile X mouse model.
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Affiliation(s)
- Victor Sabanov
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium.
| | - Sien Braat
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
| | - Laura D'Andrea
- Center for Human Genetics-VIB Center for the Biology of Disease, KULeuven, Leuven, Belgium; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy.
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
| | - Shimriet Zeidler
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
| | - Liesbeth Rooms
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium.
| | - Claudia Bagni
- Center for Human Genetics-VIB Center for the Biology of Disease, KULeuven, Leuven, Belgium; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy; Department of Fundamental Neuroscience, University of Lausanne, Switzerland.
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
| | - Detlef Balschun
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium.
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Wheeler AC, Sideris J, Hagerman R, Berry-Kravis E, Tassone F, Bailey DB. Developmental profiles of infants with an FMR1 premutation. J Neurodev Disord 2016; 8:40. [PMID: 27822316 PMCID: PMC5095966 DOI: 10.1186/s11689-016-9171-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 10/16/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Emerging evidence suggests that a subset of FMR1 premutation carriers is at an increased risk for cognitive, emotional, and medical conditions. However, because the premutation is rarely diagnosed at birth, the early developmental trajectories of children with a premutation are not known. METHODS This exploratory study examined the cognitive, communication, and social-behavioral profiles of 26 infants with a premutation who were identified through participation in a newborn screening for fragile X syndrome pilot study. In this study, families whose newborn screened positive for an FMR1 premutation were invited to participate in a longitudinal study of early development. Twenty-six infants with the premutation and 21 matched, screen-negative comparison babies were assessed using validated standardized measures at 6-month intervals starting as young as 3 months of age. The babies were assessed up to seven times over a 4-year period. RESULTS The premutation group was not statistically different from the comparison group on measures of cognitive development, adaptive behavior, temperament, or overall communication. However, the babies with the premutation had a significantly different developmental trajectory on measures of nonverbal communication and hyperresponsivity to sensory experiences. They also were significantly more hyporesponsive at all ages than the comparison group. Cytosine-guanine-guanine repeat length was linearly associated with overall cognitive development. CONCLUSIONS These results suggest that infants with a premutation may present with subtle developmental differences as young as 12 months of age that may be early markers of later anxiety, social deficits, or other challenges thought to be experienced by a subset of carriers.
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Affiliation(s)
- Anne C Wheeler
- RTI International, 3040 E. Cornwallis Road, P.O. Box 12194, Research Triangle Park, NC 27709 USA
| | - John Sideris
- University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Randi Hagerman
- Davis MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California at Davis, Davis, CA USA ; Department of Pediatrics, University of California at Davis, Davis, CA USA
| | | | - Flora Tassone
- Davis MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California at Davis, Davis, CA USA
| | - Donald B Bailey
- RTI International, 3040 E. Cornwallis Road, P.O. Box 12194, Research Triangle Park, NC 27709 USA
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Modgil A, Parakala ML, Ackley MA, Doherty JJ, Moss SJ, Davies PA. Endogenous and synthetic neuroactive steroids evoke sustained increases in the efficacy of GABAergic inhibition via a protein kinase C-dependent mechanism. Neuropharmacology 2016; 113:314-322. [PMID: 27743930 DOI: 10.1016/j.neuropharm.2016.10.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 10/03/2016] [Accepted: 10/09/2016] [Indexed: 11/16/2022]
Abstract
The neuroactive steroid (NAS) tetrahydrodeoxycorticosterone (THDOC) increases protein kinase C (PKC) mediated phosphorylation of extrasynaptic GABAA receptor (GABAAR) subunits leading to increased surface expression of α4/β3 subunit-containing extrasynaptic GABAARs, leading to a sustained increase in GABAAR tonic current density. Whether other naturally occurring and synthetic NASs share both an allosteric and metabotropic action on GABAARs is unknown. Here, we examine the allosteric and metabotropic properties of allopregnanolone (ALLO), and synthetic NASs SGE-516 and ganaxolone. ALLO, SGE-516, and ganaxolone all allosterically enhanced prototypical synaptic and extrasynaptic recombinant GABAARs. In dentate gyrus granule cells (DGGCs) all three NASs, when applied acutely, allosterically enhanced tonic and phasic GABAergic currents. In separate experiments, slices were exposed to NASs for 15 min, and then transferred to a steroid naïve recording chamber followed by ≥ 30 min wash before tonic currents were measured. A sustained increase in tonic current was observed following exposure to ALLO, or SGE-516 and was prevented by inhibiting PKC with GF 109203X. No increase in tonic current was observed with exposure to ganaxolone. In agreement with the observations of an increased tonic current, the NASs ALLO and SGE-516 increased the phosphorylation and surface expression of the β3 subunit-containing GABAARs. Our studies demonstrate that neuroactive steroids have differential abilities to induce sustained increases in the efficacy of tonic inhibition by promoting GABAAR phosphorylation and membrane trafficking dependent on PKC activity.
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Affiliation(s)
- Amit Modgil
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA
| | - Manasa L Parakala
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA
| | | | | | - Stephen J Moss
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA; Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E6BT, United Kingdom
| | - Paul A Davies
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA.
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36
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Lu P, Chen X, Feng Y, Zeng Q, Jiang C, Zhu X, Fan G, Xue Z. Integrated transcriptome analysis of human iPS cells derived from a fragile X syndrome patient during neuronal differentiation. SCIENCE CHINA. LIFE SCIENCES 2016; 59:1093-1105. [PMID: 27730449 DOI: 10.1007/s11427-016-0194-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/05/2016] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS) patients carry the expansion of over 200 CGG repeats at the promoter of fragile X mental retardation 1 (FMR1), leading to decreased or absent expression of its encoded fragile X mental retardation protein (FMRP). However, the global transcriptional alteration by FMRP deficiency has not been well characterized at single nucleotide resolution, i.e., RNA-seq. Here, we performed in-vitro neuronal differentiation of human induced pluripotent stem (iPS) cells that were derived from fibroblasts of a FXS patient (FXS-iPSC). We then performed RNA-seq and examined the transcriptional misregulation at each intermediate stage during in-vitro differentiation of FXS-iPSC into neurons. After thoroughly analyzing the transcriptomic data and integrating them with those from other platforms, we found up-regulation of many genes encoding TFs for neuronal differentiation (WNT1, BMP4, POU3F4, TFAP2C, and PAX3), down-regulation of potassium channels (KCNA1, KCNC3, KCNG2, KCNIP4, KCNJ3, KCNK9, and KCNT1) and altered temporal regulation of SHANK1 and NNAT in FXS-iPSC derived neurons, indicating impaired neuronal differentiation and function in FXS patients. In conclusion, we demonstrated that the FMRP deficiency in FXS patients has significant impact on the gene expression patterns during development, which will help to discover potential targeting candidates for the cure of FXS symptoms.
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Affiliation(s)
- Ping Lu
- Tongji Stem Cell Research Center, Tongji University School of Medicine, Shanghai, 200092, China
| | - Xiaolong Chen
- Tongji University, School of Life Sciences and Technology, Shanghai, 200092, China
| | - Yun Feng
- Tongji Stem Cell Research Center, Tongji University School of Medicine, Shanghai, 200092, China
| | - Qiao Zeng
- Tongji Stem Cell Research Center, Tongji University School of Medicine, Shanghai, 200092, China
| | - Cizhong Jiang
- Tongji University, School of Life Sciences and Technology, Shanghai, 200092, China
| | - Xianmin Zhu
- Tongji University, School of Life Sciences and Technology, Shanghai, 200092, China.
| | - Guoping Fan
- Tongji University, School of Life Sciences and Technology, Shanghai, 200092, China.
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| | - Zhigang Xue
- Tongji Stem Cell Research Center, Tongji University School of Medicine, Shanghai, 200092, China.
- Translational Center for Stem Cell Research, Tongji Hospital, Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, 200065, China.
- Tongji University Suzhou Institute, Suzhou, 215101, China.
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Hessl D, Sansone SM, Berry-Kravis E, Riley K, Widaman KF, Abbeduto L, Schneider A, Coleman J, Oaklander D, Rhodes KC, Gershon RC. The NIH Toolbox Cognitive Battery for intellectual disabilities: three preliminary studies and future directions. J Neurodev Disord 2016; 8:35. [PMID: 27602170 PMCID: PMC5012003 DOI: 10.1186/s11689-016-9167-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/11/2016] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Recent advances in understanding molecular and synaptic mechanisms of intellectual disabilities (ID) in fragile X syndrome (FXS) and Down syndrome (DS) through animal models have led to targeted controlled trials with pharmacological agents designed to normalize these underlying mechanisms and improve clinical outcomes. However, several human clinical trials have failed to demonstrate efficacy of these targeted treatments to improve surrogate behavioral endpoints. Because the ultimate index of disease modification in these disorders is amelioration of ID, the validation of cognitive measures for tracking treatment response is essential. Here, we present preliminary research to validate the National Institutes of Health Toolbox Cognitive Battery (NIH-TCB) for ID. METHODS We completed three pilot studies of patients with FXS (total n = 63; mean age 19.3 ± 8.3 years, mean mental age 5.3 ± 1.6 years), DS (n = 47; mean age 16.1 ± 6.2, mean mental age 5.4 ± 2.0), and idiopathic ID (IID; n = 16; mean age 16.1 ± 5.0, mean mental age 6.6 ± 2.3) measuring processing speed, executive function, episodic memory, word/letter reading, receptive vocabulary, and working memory using the web-based NIH-TB-CB, addressing feasibility, test-retest reliability, construct validity, ecological validity, and syndrome differences and profiles. RESULTS Feasibility was good to excellent (≥80 % of participants with valid scores) for above mental age 4 years for all tests except list sorting (working memory). Test-retest stability was good to excellent, and convergent validity was similar to or better than results obtained from typically developing children in the normal sample for executive function and language measures. Examination of ecological validity revealed moderate to very strong correlations between the NIH-TCB composite and adaptive behavior and full-scale IQ measures. Syndrome/group comparisons demonstrated significant deficits for the FXS and DS groups relative to IID on attention and inhibitory control, a significant reading weakness for FXS, and a receptive vocabulary weakness for DS. CONCLUSIONS The NIH-TCB has potential for assessing important dimensions of cognition in persons with ID, and several tests may be useful for tracking response to intervention. However, more extensive psychometric studies, evaluation of the NIH-TCB's sensitivity to change, both developmentally and in the context of treatment, and perhaps establishing links to brain function in these populations, are required to determine the true utility of the battery as a set of outcome measures.
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Affiliation(s)
- David Hessl
- Translational Psychophysiology and Assessment Laboratory (T-PAL), MIND Institute, UC Davis Medical Center, Sacramento, CA USA
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, CA USA
| | - Stephanie M. Sansone
- Translational Psychophysiology and Assessment Laboratory (T-PAL), MIND Institute, UC Davis Medical Center, Sacramento, CA USA
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, CA USA
| | - Elizabeth Berry-Kravis
- Department of Pediatrics, Rush University Medical Center, Chicago, IL USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL USA
- Department of Biochemistry, Rush University Medical Center, Chicago, IL USA
| | - Karen Riley
- Morgridge College of Education, The University of Denver, Denver, CO USA
| | - Keith F. Widaman
- Graduate School of Education, University of California Riverside, Riverside, CA USA
| | - Leonard Abbeduto
- Translational Psychophysiology and Assessment Laboratory (T-PAL), MIND Institute, UC Davis Medical Center, Sacramento, CA USA
- Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, CA USA
| | - Andrea Schneider
- Translational Psychophysiology and Assessment Laboratory (T-PAL), MIND Institute, UC Davis Medical Center, Sacramento, CA USA
- Department of Pediatrics, University of California Davis Medical Center, Sacramento, CA USA
| | - Jeanine Coleman
- Morgridge College of Education, The University of Denver, Denver, CO USA
| | - Dena Oaklander
- School of Medicine, Rush University Medical Center, Chicago, IL USA
| | - Kelly C. Rhodes
- School of Medicine, Rush University Medical Center, Chicago, IL USA
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Lozano R, Martinez-Cerdeno V, Hagerman RJ. Advances in the Understanding of the Gabaergic Neurobiology of FMR1 Expanded Alleles Leading to Targeted Treatments for Fragile X Spectrum Disorder. Curr Pharm Des 2016; 21:4972-4979. [PMID: 26365141 DOI: 10.2174/1381612821666150914121038] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022]
Abstract
Fragile X spectrum disorder (FXSD) includes: fragile X syndrome (FXS), fragile X-associated tremor ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI), as well as other medical, psychiatric and neurobehavioral problems associated with the premutation and gray zone alleles. FXS is the most common monogenetic cause of autism (ASD) and intellectual disability (ID). The understanding of the neurobiology of FXS has led to many targeted treatment trials in FXS. The first wave of phase II clinical trials in FXS were designed to target the mGluR5 pathway; however the results did not show significant efficacy and the trials were terminated. The advances in the understanding of the GABA system in FXS have shifted the focus of treatment trials to GABA agonists, and a new wave of promising clinical trials is under way. Ganaxolone and allopregnanolone (GABA agonists) have been studied in individuals with FXSD and are currently in phase II trials. Both allopregnanolone and ganaxolone may be efficacious in treatment of FXS and FXTAS, respectively. Allopregnanolone, ganaxolone, riluzole, gaboxadol, tiagabine, and vigabatrin are potential GABAergic treatments. The lessons learned from the initial trials have not only shifted the targeted system, but also have refined the design of clinical trials. The results of these new trials will likely impact further clinical trials for FXS and other genetic disorders associated with ASD.
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Affiliation(s)
- Reymundo Lozano
- Icahn School of Medicine at Mount Sinai, New York, NY USA; Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Veronica Martinez-Cerdeno
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospital for Children of Northern California, Sacramento, CA, USA; Department of Pathology and Laboratory Medicine, UC Davis, Sacramento, USA
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Department of Pediatrics, UC Davis, Sacramento, CA, USA
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Abstract
Fragile X syndrome (FXS) is the most common inherited form of intellectual disability, and is the leading single-gene cause of autism spectrum disorders. It is due to a loss of the fragile X mental retardation protein, which leads to molecular, behavioral, and cognitive deficits in these patients. Improvements in our understanding of its pathophysiology have led to the development of numerous targeted treatments in FXS as highlighted by metabotropic glutamate receptor antagonists and gamma-Aminobutyric acid receptor modulators. This review will summarize relevant pre-clinical data and results from clinical trials in human subjects with FXS. It will also highlight upcoming studies and future directions for clinical trials as well.
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Affiliation(s)
- Andrew Ligsay
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, Sacramento, CA, USA
- University of California, Davis School of Medicine, Sacramento, CA, USA
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, Sacramento, CA, USA
- Department of Pediatrics, University of California, Davis Medical Center, Sacramento, CA, USA
- Address correspondence to: Dr. Randi J Hagerman, Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis Medical Center, 2825 50th Street, Sacramento, CA 95817, USA. E-mail:
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40
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Lozano R, Azarang A, Wilaisakditipakorn T, Hagerman RJ. Fragile X syndrome: A review of clinical management. Intractable Rare Dis Res 2016; 5:145-57. [PMID: 27672537 PMCID: PMC4995426 DOI: 10.5582/irdr.2016.01048] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The fragile X mental retardation 1 gene, which codes for the fragile X mental retardation 1 protein, usually has 5 to 40 CGG repeats in the 5' untranslated promoter. The full mutation is the almost always the cause of fragile X syndrome (FXS). The prevalence of FXS is about 1 in 4,000 to 1 in 7,000 in the general population although the prevalence varies in different regions of the world. FXS is the most common inherited cause of intellectual disability and autism. The understanding of the neurobiology of FXS has led to many targeted treatments, but none have cured this disorder. The treatment of the medical problems and associated behaviors remain the most useful intervention for children with FXS. In this review, we focus on the non-pharmacological and pharmacological management of medical and behavioral problems associated with FXS as well as current recommendations for follow-up and surveillance.
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Affiliation(s)
- Reymundo Lozano
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA
- Department of Pediatrics, UC Davis, Sacramento, CA, USA
- Address correspondence to: Dr. Reymundo Lozano, Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA; Department of Pediatrics, UC Davis, Sacramento, CA, USA. E-mail:
| | - Atoosa Azarang
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA
- Department of Pediatrics, UC Davis, Sacramento, CA, USA
| | - Tanaporn Wilaisakditipakorn
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA
- Department of Pediatrics, UC Davis, Sacramento, CA, USA
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders MIND Institute, UC Davis, CA, USA
- Department of Pediatrics, UC Davis, Sacramento, CA, USA
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Colavita M, Terral G, Lemercier CE, Drago F, Marsicano G, Massa F. Layer-specific potentiation of network GABAergic inhibition in the CA1 area of the hippocampus. Sci Rep 2016; 6:28454. [PMID: 27345695 PMCID: PMC4921906 DOI: 10.1038/srep28454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 06/03/2016] [Indexed: 12/04/2022] Open
Abstract
One of the most important functions of GABAergic inhibition in cortical regions is the tight control of spatiotemporal activity of principal neuronal ensembles. However, electrophysiological recordings do not provide sufficient spatial information to determine the spatiotemporal properties of inhibitory plasticity. Using Voltage Sensitive Dye Imaging (VSDI) in mouse hippocampal slices, we demonstrate that GABAA-mediated field inhibitory postsynaptic potentials undergo layer-specific potentiation upon activation of metabotropic glutamate receptors (mGlu). VSDI recordings allowed detection of pharmacologically isolated GABAA-dependent hyperpolarization signals. Bath-application of the selective group-I mGlu receptor agonist, (S)-3,5-Dihydroxyphenylglycine (DHPG), induces an enhancement of the GABAergic VSDI-recorded signal, which is more or less pronounced in different hippocampal layers. This potentiation is mediated by mGlu5 and downstream activation of IP3 receptors. Our results depict network GABAergic activity in the hippocampal CA1 region and its sub-layers, showing also a novel form of inhibitory synaptic plasticity tightly coupled to glutamatergic activity.
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Affiliation(s)
- Michelangelo Colavita
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France.,University of Catania, Biometec - Department of Biomedical and Biotechnological Sciences, 95125 Catania, Italy
| | - Geoffrey Terral
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
| | - Clement E Lemercier
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
| | - Filippo Drago
- University of Catania, Biometec - Department of Biomedical and Biotechnological Sciences, 95125 Catania, Italy
| | - Giovanni Marsicano
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
| | - Federico Massa
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
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Frye RE, Casanova MF, Fatemi SH, Folsom TD, Reutiman TJ, Brown GL, Edelson SM, Slattery JC, Adams JB. Neuropathological Mechanisms of Seizures in Autism Spectrum Disorder. Front Neurosci 2016; 10:192. [PMID: 27242398 PMCID: PMC4861974 DOI: 10.3389/fnins.2016.00192] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 04/18/2016] [Indexed: 01/09/2023] Open
Abstract
This manuscript reviews biological abnormalities shared by autism spectrum disorder (ASD) and epilepsy. Two neuropathological findings are shared by ASD and epilepsy: abnormalities in minicolumn architecture and γ-aminobutyric acid (GABA) neurotransmission. The peripheral neuropil, which is the region that contains the inhibition circuits of the minicolumns, has been found to be decreased in the post-mortem ASD brain. ASD and epilepsy are associated with inhibitory GABA neurotransmission abnormalities including reduced GABAA and GABAB subunit expression. These abnormalities can elevate the excitation-to-inhibition balance, resulting in hyperexcitablity of the cortex and, in turn, increase the risk of seizures. Medical abnormalities associated with both epilepsy and ASD are discussed. These include specific genetic syndromes, specific metabolic disorders including disorders of energy metabolism and GABA and glutamate neurotransmission, mineral and vitamin deficiencies, heavy metal exposures and immune dysfunction. Many of these medical abnormalities can result in an elevation of the excitatory-to-inhibitory balance. Fragile X is linked to dysfunction of the mGluR5 receptor and Fragile X, Angelman and Rett syndromes are linked to a reduction in GABAA receptor expression. Defects in energy metabolism can reduce GABA interneuron function. Both pyridoxine dependent seizures and succinic semialdehyde dehydrogenase deficiency cause GABA deficiencies while urea cycle defects and phenylketonuria cause abnormalities in glutamate neurotransmission. Mineral deficiencies can cause glutamate and GABA neurotransmission abnormalities and heavy metals can cause mitochondrial dysfunction which disrupts GABA metabolism. Thus, both ASD and epilepsy are associated with similar abnormalities that may alter the excitatory-to-inhibitory balance of the cortex. These parallels may explain the high prevalence of epilepsy in ASD and the elevated prevalence of ASD features in individuals with epilepsy.
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Affiliation(s)
- Richard E Frye
- Autism Research Program, Arkansas Children's Research InstituteLittle Rock, AR, USA; Department of Pediatrics, University of Arkansas for Medical SciencesLittle Rock, AR, USA
| | - Manuel F Casanova
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville Greenville, SC, USA
| | - S Hossein Fatemi
- Department of Psychiatry, University of Minnesota Medical School Minneapolis, MN, USA
| | - Timothy D Folsom
- Department of Psychiatry, University of Minnesota Medical School Minneapolis, MN, USA
| | - Teri J Reutiman
- Department of Psychiatry, University of Minnesota Medical School Minneapolis, MN, USA
| | | | | | - John C Slattery
- Autism Research Program, Arkansas Children's Research InstituteLittle Rock, AR, USA; Department of Pediatrics, University of Arkansas for Medical SciencesLittle Rock, AR, USA
| | - James B Adams
- School for Engineering of Matter, Transport, and Energy, Arizona State University Tempe, AZ, USA
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43
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Casanova EL, Sharp JL, Chakraborty H, Sumi NS, Casanova MF. Genes with high penetrance for syndromic and non-syndromic autism typically function within the nucleus and regulate gene expression. Mol Autism 2016; 7:18. [PMID: 26985359 PMCID: PMC4793536 DOI: 10.1186/s13229-016-0082-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/01/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Intellectual disability (ID), autism, and epilepsy share frequent yet variable comorbidities with one another. In order to better understand potential genetic divergence underlying this variable risk, we studied genes responsible for monogenic IDs, grouped according to their autism and epilepsy comorbidities. METHODS Utilizing 465 different forms of ID with known molecular origins, we accessed available genetic databases in conjunction with gene ontology (GO) to determine whether the genetics underlying ID diverge according to its comorbidities with autism and epilepsy and if genes highly penetrant for autism or epilepsy share distinctive features that set them apart from genes that confer comparatively variable or no apparent risk. RESULTS The genetics of ID with autism are relatively enriched in terms associated with nervous system-specific processes and structural morphogenesis. In contrast, we find that ID with highly comorbid epilepsy (HCE) is modestly associated with lipid metabolic processes while ID without autism or epilepsy comorbidity (ID only) is enriched at the Golgi membrane. Highly comorbid autism (HCA) genes, on the other hand, are strongly enriched within the nucleus, are typically involved in regulation of gene expression, and, along with IDs with more variable autism, share strong ties with a core protein-protein interaction (PPI) network integral to basic patterning of the CNS. CONCLUSIONS According to GO terminology, autism-related gene products are integral to neural development. While it is difficult to draw firm conclusions regarding IDs unassociated with autism, it is clear that the majority of HCA genes are tightly linked with general dysregulation of gene expression, suggesting that disturbances to the chronology of neural maturation and patterning may be key in conferring susceptibility to autism spectrum conditions.
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Affiliation(s)
- Emily L. Casanova
- />Department of Biomedical Sciences, University of South Carolina, South Carolina, USA
- />Department of Pediatrics, Greenville Health System, Patewood Medical Campus, 200A Patewood Dr, Greenville, SC 29615 USA
| | - Julia L. Sharp
- />Department of Mathematical Sciences, Clemson University, Clemson, USA
| | - Hrishikesh Chakraborty
- />Department of Biostatistics and Epidemiology, University of South Carolina, South Carolina, USA
| | - Nahid Sultana Sumi
- />Department of Biostatistics and Epidemiology, University of South Carolina, South Carolina, USA
| | - Manuel F. Casanova
- />Department of Biomedical Sciences, University of South Carolina, South Carolina, USA
- />Department of Pediatrics, Greenville Health System, Patewood Medical Campus, 200A Patewood Dr, Greenville, SC 29615 USA
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Abstract
Intellectual disability, autism spectrum disorder, and epilepsy are prime examples of neurodevelopmental disorders that collectively affect a significant percentage of the world population. Recent technological breakthroughs allowed the elucidation of the genetic causes of many of these disorders. As neurodevelopmental disorders are genetically heterogeneous, the development of rational therapy is extremely challenging. Fortunately, many causative genes are interconnected and cluster in specific cellular pathways. Targeting a common node in such a network would allow us to interfere with a series of related neurodevelopmental disorders at once. Here, we argue that the GABAergic system is disturbed in many neurodevelopmental disorders, including fragile X syndrome, Rett syndrome, and Dravet syndrome, and is a key candidate target for therapeutic intervention. Many drugs that modulate the GABAergic system have already been tested in animal models with encouraging outcomes and are readily available for clinical trials.
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Affiliation(s)
- Sien Braat
- Department of Medical Genetics, University of Antwerp, Prins Boudewijnlaan 43, 2650 Edegem, Belgium
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Prins Boudewijnlaan 43, 2650 Edegem, Belgium.
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45
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Winarni TI, Schneider A, Ghaziuddin N, Seritan A, Hagerman RJ. Psychosis and catatonia in fragile X: Case report and literature review. Intractable Rare Dis Res 2015; 4:139-46. [PMID: 26361565 PMCID: PMC4561243 DOI: 10.5582/irdr.2015.01028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 07/31/2015] [Accepted: 08/12/2015] [Indexed: 12/13/2022] Open
Abstract
Fragile X mental retardation 1 (FMR1) premutation associated phenotypes have been explored extensively since the molecular mechanism emerged involving elevated FMR1 messenger ribonucleic acid (mRNA) levels. Lowered fragile X mental retardation protein (FMRP) can also occur which may have an additive effect to the high levels of mRNA leading to neurodevelopmental problems and psychopathology. This paper was aimed to review psychosis and catatonia in premutation carriers, express the role of elevated FMR1 mRNA and lowered FMRP in the phenotype of carriers and present a case of psychosis and catatonia in a carrier. This case also demonstrates additional genetic and environmental factors which may also affect the phenotype. We review the literature and report an exemplary case of a 25 year old male premutation carrier with elevated FMR1 mRNA, low FMRP, a cytochrome P450 family 2 subfamily D polypeptide 6 (CYP2D6)*2xN mutation and a perinatal insult. This patient developed an autism spectrum disorder, psychosis, catatonia with subsequent cognitive decline after electro-convulsive therapy (ECT) for his catatonia. He had a premutation of 72 CGG repeat in FMR1, FMR1 mRNA level that was over 2.4 times normal and FMRP level at 18% of normal, and additionally, a CYP2D6 allelic variant which leads to ultrarapid metabolism (UM) of medication. There is an overlapping pathophysiological mechanism of catatonia and fragile X-associated premutation phenotypes including autism and psychosis. This case demonstrates the shared phenotype and the overlap of the pathophysiological mechanisms that can influence the intervention. Multiple genetic and environmental hits can lead to more significant involvement in premutation carriers.
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Affiliation(s)
- Tri Indah Winarni
- MIND Institute, University of California Davis, Medical Center, Sacramento, USA
- Center for Biomedical Research (CEBIOR), Faculty of Medicine Diponegoro University, Semarang, Indonesia
| | - Andrea Schneider
- MIND Institute, University of California Davis, Medical Center, Sacramento, USA
- Department of Pediatrics, University of California Davis, Medical Center, Sacramento, USA
| | - Neera Ghaziuddin
- University of Michigan Hospitals and Health Center, Ann Arbor, USA
| | - Andreea Seritan
- Department of Psychiatry and Behavioral Sciences, University of California Davis, Medical Center, Sacramento, USA
| | - Randi J Hagerman
- MIND Institute, University of California Davis, Medical Center, Sacramento, USA
- Department of Pediatrics, University of California Davis, Medical Center, Sacramento, USA
- Address correspondence to: Dr. Randi J. Hagerman, MIND Institute, UC Davis Health System, 2825 50th Street, Sacramento, CA 95817, USA. E-mail:
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DSM-5 changes and the prevalence of parent-reported autism spectrum symptoms in Fragile X syndrome. J Autism Dev Disord 2015; 45:816-29. [PMID: 25234484 DOI: 10.1007/s10803-014-2246-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We used survey methodology to assess parent-reported autism symptomology in 758 individuals (639 males; 119 females) with fragile X syndrome (FXS). Caregivers reported whether their child with FXS had been diagnosed with an autism spectrum disorder (ASD) and endorsed symptoms based on a list of observable behaviors related to ASD diagnoses. Symptom counts were categorized based on DSM-IV-TR and DSM-5 criteria. Based on behavioral symptoms endorsed by caregivers, 38.7 % of males and 24.7 % of females met criteria for DSM-IV-TR diagnosis of autistic disorder. Significantly fewer males (27.8 %) and females (11.3 %) met criteria for ASD based on DSM-5 criteria. Although 86.4 % of males and 61.7 % of females met criteria for the restricted and repetitive behavior domain for DSM-5, only 29.4 % of males and 13.0 % of females met criteria for the social communication and interaction (SCI) domain. Relaxing the social communication criteria by one symptom count led to a threefold increase in those meeting criteria for ASD, suggesting the importance of subthreshold SCI symptoms for individuals with FXS in ASD diagnoses. Findings suggest important differences in the way ASD may be conceptualized in FXS based on the new DSM-5 criteria.
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Abstract
Over the last several years, evidence has accumulated that the GABAA receptor is compromised in animal models for fragile X syndrome (FXS), a common hereditary form of intellectual disability. In mouse and fly models, agonists of the GABAA receptor were able to rescue specific consequences of the fragile X mutation. Here, we imaged and quantified GABAA receptors in vivo in brain of fragile X patients using Positron Emission Topography (PET) and [11C]flumazenil, a known high-affinity and specific ligand for the benzodiazepine site of GABAA receptors. We measured regional GABAA receptor availability in 10 fragile X patients and 10 control subjects. We found a significant reduction of on average 10% in GABAA receptor binding potential throughout the brain in fragile X patients. In the thalamus, the brain region showing the largest difference, the GABAA receptor availability was even reduced with 17%. This is one of the first reports of a PET study of human fragile X brain and directly demonstrates that the GABAA receptor availability is reduced in fragile X patients. The study reinforces previous hypotheses that the GABAA receptor is a potential target for rational pharmacological treatment of fragile X syndrome.
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48
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Joseph J, Gara MA, Silverstein SM. Hierarchical Classes Analysis (HICLAS): A novel data reduction method to examine associations between biallelic SNPs and perceptual organization phenotypes in schizophrenia. Schizophr Res Cogn 2015; 2:56-63. [PMID: 26346124 PMCID: PMC4559868 DOI: 10.1016/j.scog.2015.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The power of SNP association studies to detect valid relationships with clinical phenotypes in schizophrenia is largely limited by the number of SNPs selected and non-specificity of phenotypes. To address this, we first assessed performance on two visual perceptual organization tasks designed to avoid many generalized deficit confounds, Kanizsa shape perception and contour integration, in a schizophrenia patient sample. Then, to reduce the total number of candidate SNPs analyzed in association with perceptual organization phenotypes, we employed a two-stage strategy: first a priori SNPs from three candidate genes were selected (GAD1, NRG1 and DTNBP1); then a Hierarchical Classes Analysis (HICLAS) was performed to reduce the total number of SNPs, based on statistically related SNP clusters. HICLAS reduced the total number of candidate SNPs for subsequent phenotype association analyses from 6 to 3. MANCOVAs indicated that rs10503929 and rs1978340 were associated with the Kanizsa shape perception filling in metric but not the global shape detection metric. rs10503929 was also associated with altered contour integration performance. SNPs not selected by the HICLAS model were unrelated to perceptual phenotype indices. While the contribution of candidate SNPs to perceptual impairments requires further clarification, this study reports the first application of HICLAS as a hypothesis-independent mathematical method for SNP data reduction. HICLAS may be useful for future larger scale genotype-phenotype association studies.
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Affiliation(s)
- Jamie Joseph
- Rutgers University Graduate School of Biomedical Sciences, 675 Hoes Lane, Piscataway, NJ 08854, USA
- Rutgers University Behavioral Health Care, 151 Centennial Ave, Piscataway, NJ 08854, USA
| | - Michael A. Gara
- Rutgers University Behavioral Health Care, 151 Centennial Ave, Piscataway, NJ 08854, USA
- Rutgers–Robert Wood Johnson Medical School, 671 Hoes Lane, Piscataway, NJ 08854, USA
| | - Steven M. Silverstein
- Rutgers University Behavioral Health Care, 151 Centennial Ave, Piscataway, NJ 08854, USA
- Rutgers–Robert Wood Johnson Medical School, 671 Hoes Lane, Piscataway, NJ 08854, USA
- Corresponding author at: Department of Psychiatry, Rutgers University Behavioral Health Care and Robert Wood Johnson Medical School, 671 Hoes Lane, Piscataway, NJ 08854, USA.
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Qin M, Huang T, Kader M, Krych L, Xia Z, Burlin T, Zeidler Z, Zhao T, Smith CB. R-Baclofen Reverses a Social Behavior Deficit and Elevated Protein Synthesis in a Mouse Model of Fragile X Syndrome. Int J Neuropsychopharmacol 2015; 18:pyv034. [PMID: 25820841 PMCID: PMC4576516 DOI: 10.1093/ijnp/pyv034] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/16/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common known inherited form of intellectual disability and the single genomic cause of autism spectrum disorders. It is caused by the absence of a fragile X mental retardation gene (Fmr1) product, FMRP, an RNA-binding translation suppressor. Elevated rates of protein synthesis in the brain and an imbalance between synaptic signaling via glutamate and γ-aminobutyric acid (GABA) are both considered important in the pathogenesis of FXS. In a mouse model of FXS (Fmr1 knockout [KO]), treatment with R-baclofen reversed some behavioral and biochemical phenotypes. A remaining crucial question is whether R-baclofen is also able to reverse increased brain protein synthesis rates. METHODS To answer this question, we measured regional rates of cerebral protein synthesis in vivo with the L-[1-(14)C]leucine method in vehicle- and R-baclofen-treated wildtype and Fmr1 KO mice. We further probed signaling pathways involved in the regulation of protein synthesis. RESULTS Acute R-baclofen administration corrected elevated protein synthesis and reduced deficits on a test of social behavior in adult Fmr1 KO mice. It also suppressed activity of the mammalian target of rapamycin pathway, particularly in synaptosome-enriched fractions, but it had no effect on extracellular-regulated kinase 1/2 activity. Ninety min after R-baclofen treatment, we observed an increase in metabotropic glutamate receptor 5 expression in the frontal cortex, a finding that may shed light on the tolerance observed in human studies with this drug. CONCLUSIONS Our results suggest that treatment via activation of the GABA (GABA receptor subtype B) system warrants further study in patients with FXS.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Carolyn B Smith
- Section on Neuroadaptation and Protein Metabolism, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD (Drs Qin, Huang, Kader, Krych, Xia, Burlin, Zeidler, Zhao, and Smith)
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Yudkin DV, Lemskaya NA, Grischenko IV, Dolskiy AA. Chromatin changes caused by expansion of CGG repeats in fmr1 gene. Mol Biol 2015. [DOI: 10.1134/s0026893315010197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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