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Varga A, Kedves R, Sághy K, Garab D, Zádor F, Lendvai B, Lévay G, Román V. R-Baclofen Treatment Corrects Autistic-like Behavioral Deficits in the RjIbm(m):FH Fawn-Hooded Rat Strain. Pharmaceuticals (Basel) 2024; 17:939. [PMID: 39065788 PMCID: PMC11279403 DOI: 10.3390/ph17070939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
The Fawn-hooded rat has long been used as a model for various peripheral and central disorders and the data available indicate that the social behavior of this strain may be compromised. However, a thorough description of the Fawn-hooded rat is unavailable in this regard. The objective of the present study was to investigate various aspects of the Fawn-hooded rat's social behavior in depth. Our results show that several facets of socio-communicational behavior are impaired in the RjIbm(m):FH strain, including defective ultrasonic vocalizations in pups upon maternal deprivation, reduced social play in adolescence and impaired social novelty discrimination in adulthood. In addition, Fawn-hooded rats exhibited heightened tactile sensitivity and hyperactivity. The defects observed were comparable to those induced by prenatal valproate exposure, a widely utilized model of autism spectrum disorder. Further on, the pro-social drug R-baclofen (0.25-1 mg/kg) reversed the autistic-like defects observed in Fawn-hooded rats, specifically the deficiency in ultrasonic vocalization, tactile sensitivity and social novelty discrimination endpoints. In conclusion, the asocial, hypersensitive and hyperactive phenotype as well as the responsivity to R-baclofen indicate this variant of the Fawn-hooded rat strain may serve as a model of autism spectrum disorder and could be useful in the identification of novel drug candidates.
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Affiliation(s)
- Anita Varga
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
- Doctoral School of Biology and Institute of Biology, Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
| | - Rita Kedves
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Katalin Sághy
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Dénes Garab
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Ferenc Zádor
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Balázs Lendvai
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
- Richter Department, Semmelweis University, Gyömrői út 19-21, 1103 Budapest, Hungary
| | - György Lévay
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
- Department of Morphology and Physiology, Faculty of Health Sciences, Semmelweis University, Vas utca 17, 1088 Budapest, Hungary
| | - Viktor Román
- Pharmacology and Drug Safety Research, Gedeon Richter Plc., Gyömrői út 19-21, 1103 Budapest, Hungary
- Richter Department, Semmelweis University, Gyömrői út 19-21, 1103 Budapest, Hungary
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Stamenkovic V, Lautz JD, Harsh FM, Smith SEP. SRC family kinase inhibition rescues molecular and behavioral phenotypes, but not protein interaction network dynamics, in a mouse model of Fragile X syndrome. Mol Psychiatry 2024; 29:1392-1405. [PMID: 38297084 DOI: 10.1038/s41380-024-02418-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 01/02/2024] [Accepted: 01/05/2024] [Indexed: 02/02/2024]
Abstract
Glutamatergic synapses encode information from extracellular inputs using dynamic protein interaction networks (PINs) that undergo widespread reorganization following synaptic activity, allowing cells to distinguish between signaling inputs and generate coordinated cellular responses. Here, we investigate how Fragile X Messenger Ribonucleoprotein (FMRP) deficiency disrupts signal transduction through a glutamatergic synapse PIN downstream of NMDA receptor or metabotropic glutamate receptor (mGluR) stimulation. In cultured cortical neurons or acute cortical slices from P7, P17 and P60 FMR1-/y mice, the unstimulated protein interaction network state resembled that of wildtype littermates stimulated with mGluR agonists, demonstrating resting state pre-activation of mGluR signaling networks. In contrast, interactions downstream of NMDAR stimulation were similar to WT. We identified the Src family kinase (SFK) Fyn as a network hub, because many interactions involving Fyn were pre-activated in FMR1-/y animals. We tested whether targeting SFKs in FMR1-/y mice could modify disease phenotypes, and found that Saracatinib (SCB), an SFK inhibitor, normalized elevated basal protein synthesis, novel object recognition memory and social behavior in FMR1-/y mice. However, SCB treatment did not normalize the PIN to a wild-type-like state in vitro or in vivo, but rather induced extensive changes to protein complexes containing Shank3, NMDARs and Fyn. We conclude that targeting abnormal nodes of a PIN can identify potential disease-modifying drugs, but behavioral rescue does not correlate with PIN normalization.
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Affiliation(s)
- Vera Stamenkovic
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Jonathan D Lautz
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Felicia M Harsh
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Stephen E P Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, USA.
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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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Sharghi S, Flunkert S, Daurer M, Rabl R, Chagnaud BP, Leopoldo M, Lacivita E, Hutter-Paier B, Prokesch M. Evaluating the effect of R-Baclofen and LP-211 on autistic behavior of the BTBR and Fmr1-KO mouse models. Front Neurosci 2023; 17:1087788. [PMID: 37065917 PMCID: PMC10097904 DOI: 10.3389/fnins.2023.1087788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
IntroductionAutism spectrum disorder (ASD) is a persistent neurodevelopmental condition characterized by two core behavioral symptoms: impaired social communication and interaction, as well as stereotypic, repetitive behavior. No distinct cause of ASD is known so far; however, excitatory/inhibitory imbalance and a disturbed serotoninergic transmission have been identified as prominent candidates responsible for ASD etiology.MethodsThe GABAB receptor agonist R-Baclofen and the selective agonist for the 5HT7 serotonin receptor LP-211 have been reported to correct social deficits and repetitive behaviors in mouse models of ASD. To evaluate the efficacy of these compounds in more details, we treated BTBR T+ Itpr3tf/J and B6.129P2-Fmr1tm1Cgr/J mice acutely with R-Baclofen or LP-211 and evaluated the behavior of animals in a series of tests.ResultsBTBR mice showed motor deficits, elevated anxiety, and highly repetitive behavior of self-grooming. Fmr1-KO mice exhibited decreased anxiety and hyperactivity. Additionally, Fmr1-KO mice’s ultrasonic vocalizations were impaired suggesting a reduced social interest and communication of this strain. Acute LP-211 administration did not affect the behavioral abnormalities observed in BTBR mice but improved repetitive behavior in Fmr1-KO mice and showed a trend to change anxiety of this strain. Acute R-Baclofen treatment improved repetitive behavior only in Fmr1-KO mice.ConclusionOur results add value to the current available data on these mouse models and the respective compounds. Yet, additional studies are needed to further test R-Baclofen and LP-211 as potential treatments for ASD therapy.
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Affiliation(s)
- Shirin Sharghi
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
- Institute for Biology, Karl-Franzens-Universität Graz, Graz, Austria
- *Correspondence: Shirin Sharghi,
| | - Stefanie Flunkert
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
| | - Magdalena Daurer
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
| | - Roland Rabl
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
| | | | - Marcello Leopoldo
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Enza Lacivita
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | | | - Manuela Prokesch
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
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Crawley JN. Twenty years of discoveries emerging from mouse models of autism. Neurosci Biobehav Rev 2023; 146:105053. [PMID: 36682425 DOI: 10.1016/j.neubiorev.2023.105053] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 01/12/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
More than 100 single gene mutations and copy number variants convey risk for autism spectrum disorder. To understand the extent to which each mutation contributes to the trajectory of individual symptoms of autism, molecular genetics laboratories have introduced analogous mutations into the genomes of laboratory mice and other species. Over the past twenty years, behavioral neuroscientists discovered the consequences of mutations in many risk genes for autism in animal models, using assays with face validity to the diagnostic and associated behavioral symptoms of people with autism. Identified behavioral phenotypes complement electrophysiological, neuroanatomical, and biochemical outcome measures in mutant mouse models of autism. This review describes the history of phenotyping assays in genetic mouse models, to evaluate social and repetitive behaviors relevant to the primary diagnostic criteria for autism. Robust phenotypes are currently employed in translational investigations to discover effective therapeutic interventions, representing the future direction of an intensely challenging research field.
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Abstract
The fragile X-related disorders are an important group of hereditary disorders that are caused by expanded CGG repeats in the 5' untranslated region of the FMR1 gene or by mutations in the coding sequence of this gene. Two categories of pathological CGG repeats are associated with these disorders, full mutation alleles and shorter premutation alleles. Individuals with full mutation alleles develop fragile X syndrome, which causes autism and intellectual disability, whereas those with premutation alleles, which have shorter CGG expansions, can develop fragile X-associated tremor/ataxia syndrome, a progressive neurodegenerative disease. Thus, fragile X-related disorders can manifest as neurodegenerative or neurodevelopmental disorders, depending on the size of the repeat expansion. Here, we review mouse models of fragile X-related disorders and discuss how they have informed our understanding of neurodegenerative and neurodevelopmental disorders. We also assess the translational value of these models for developing rational targeted therapies for intellectual disability and autism disorders.
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Affiliation(s)
- Rob Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
| | - R Frank Kooy
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
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Schmidt KC, Loutaev I, Burlin TV, Thurm A, Sheeler C, Smith CB. Decreased rates of cerebral protein synthesis in conscious young adults with fragile X syndrome demonstrated by L-[1- 11C]leucine PET. J Cereb Blood Flow Metab 2022; 42:1666-1675. [PMID: 35350914 PMCID: PMC9441731 DOI: 10.1177/0271678x221090997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability. Fragile X mental retardation protein, a putative translation suppressor, is significantly reduced in FXS. The prevailing hypothesis is that rates of cerebral protein synthesis (rCPS) are increased by the absence of this regulatory protein. We have previously reported increased rCPS in the Fmr1 knockout mouse model of FXS. To address the hypothesis in human subjects, we measured rCPS in young men with FXS with L-[1-11C]leucine PET. In previous studies we had used sedation during imaging, and we did not find increases in rCPS as had been seen in the mouse model. Since mouse measurements were conducted in awake animals, we considered the possibility that sedation may have confounded our results. In the present study we used a modified and validated PET protocol that made it easier for participants with FXS to undergo the study awake. We compared rCPS in 10 fragile X participants and 16 healthy controls all studied while awake. Contrary to the prevailing hypothesis and findings in Fmr1 knockout mice, results indicate that rCPS in awake participants with FXS are decreased in whole brain and most brain regions by 13-21% compared to healthy controls.
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Affiliation(s)
- Kathleen C Schmidt
- Section on Neuroadaptation & Protein Metabolism, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Inna Loutaev
- Section on Neuroadaptation & Protein Metabolism, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Thomas V Burlin
- Section on Neuroadaptation & Protein Metabolism, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Audrey Thurm
- Neurodevelopmental and Behavioral Phenotyping Service, Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Carrie Sheeler
- Section on Neuroadaptation & Protein Metabolism, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Carolyn Beebe Smith
- Section on Neuroadaptation & Protein Metabolism, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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Saré RM, Lemons A, Smith CB. Effects of Treatment With Hypnotics on Reduced Sleep Duration and Behavior Abnormalities in a Mouse Model of Fragile X Syndrome. Front Neurosci 2022; 16:811528. [PMID: 35720683 PMCID: PMC9202518 DOI: 10.3389/fnins.2022.811528] [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] [Received: 11/08/2021] [Accepted: 05/10/2022] [Indexed: 11/28/2022] Open
Abstract
Many patients with fragile X syndrome (FXS) have sleep disturbances, and Fmr1 knockout (KO) mice (a model of FXS) have reduced sleep duration compared to wild type (WT). Sleep is important for brain development, and chronic sleep restriction during development has long-lasting behavioral effects in WT mice. We hypothesized that the sleep abnormalities in FXS may contribute to behavioral impairments and that increasing sleep duration might improve behavior. We treated adult male Fmr1 KO and WT mice subacutely with three different classes of hypnotics (DORA-22, ramelteon, and zolpidem) and caffeine, a methylxanthine stimulant, and we tested the effects of treatments on sleep duration and behavior. Behavior tests included activity response to a novel environment, anxiety-like behavior, and social behavior. As expected, all hypnotics increased, and caffeine decreased sleep duration in the circadian phase in which drugs were administered. Caffeine and DORA-22 treatment significantly reduced activity in the open field regardless of genotype. Other effects were not as apparent.
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Keeping the Balance: GABAB Receptors in the Developing Brain and Beyond. Brain Sci 2022; 12:brainsci12040419. [PMID: 35447949 PMCID: PMC9031223 DOI: 10.3390/brainsci12040419] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 12/16/2022] Open
Abstract
The main neurotransmitter in the brain responsible for the inhibition of neuronal activity is γ-aminobutyric acid (GABA). It plays a crucial role in circuit formation during development, both via its primary effects as a neurotransmitter and also as a trophic factor. The GABAB receptors (GABABRs) are G protein-coupled metabotropic receptors; on one hand, they can influence proliferation and migration; and, on the other, they can inhibit cells by modulating the function of K+ and Ca2+ channels, doing so on a slower time scale and with a longer-lasting effect compared to ionotropic GABAA receptors. GABABRs are expressed pre- and post-synaptically, at both glutamatergic and GABAergic terminals, thus being able to shape neuronal activity, plasticity, and the balance between excitatory and inhibitory synaptic transmission in response to varying levels of extracellular GABA concentration. Furthermore, given their subunit composition and their ability to form complexes with several associated proteins, GABABRs display heterogeneity with regard to their function, which makes them a promising target for pharmacological interventions. This review will describe (i) the latest results concerning GABABRs/GABABR-complex structures, their function, and the developmental time course of their appearance and functional integration in the brain, (ii) their involvement in manifestation of various pathophysiological conditions, and (iii) the current status of preclinical and clinical studies involving GABABR-targeting drugs.
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Jiang S, Xiao L, Sun Y, He M, Gao C, Zhu C, Chang H, Ding J, Li W, Wang Y, Sun T, Wang F. The GABAB receptor agonist STX209 reverses the autism‑like behaviour in an animal model of autism induced by prenatal exposure to valproic acid. Mol Med Rep 2022; 25:154. [PMID: 35244195 PMCID: PMC8941376 DOI: 10.3892/mmr.2022.12670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/16/2022] [Indexed: 11/06/2022] Open
Abstract
Autism spectrum disorder (ASD) is a lifelong neurodevelopmental condition characterized by impaired social interaction, compromised communication, and restrictive or stereotyped behaviours and interests. Due to the complex pathophysiology of ASD, there are currently no available medical therapies for improving the associated social deficits. Consequently, the present study investigated the effects of STX209, a selective γ‑aminobutyric acid type B receptor (GABABR2) agonist, on an environmental rodent model of autism. The mouse model of autism induced by prenatal exposure to valproic acid (VPA) was used to assess the therapeutic potential of STX209 on autism‑like behaviour in the present study. This study investigated the effects of STX209 on VPA model mice via behavioral testing and revealed a significant reversal of core/associated autism‑like behavior, including sociability and preference for social novelty, novelty recognition, locomotion and exploration activity and marble‑burying deficit. This may be associated with STX209 correcting dendritic arborization, spine density and GABABR2 expression in hippocampus of VPA model mice. However, expression of glutamic acid decarboxylase 65/67 in the hippocampus were not altered by STX209. The present results demonstrated that STX209 administration ameliorated autism‑like symptoms in mice exposed to VPA prenatally, suggesting that autism‑like symptoms in children with a history of prenatal VPA exposure may also benefit from treatment with the GABABR2 agonist STX209.
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Affiliation(s)
- Shucai Jiang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Lifei Xiao
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yu Sun
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Maotao He
- Department of Diagnostic Pathology, School of Basic Medical Sciences, Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Caibin Gao
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Changliang Zhu
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Haigang Chang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Jiangwei Ding
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Wenchao Li
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yangyang Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Tao Sun
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Feng Wang
- Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, P.R. China
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Kenny A, Wright D, Stanfield AC. EEG as a translational biomarker and outcome measure in fragile X syndrome. Transl Psychiatry 2022; 12:34. [PMID: 35075104 PMCID: PMC8786970 DOI: 10.1038/s41398-022-01796-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 12/01/2021] [Accepted: 01/12/2022] [Indexed: 01/08/2023] Open
Abstract
Targeted treatments for fragile X syndrome (FXS) have frequently failed to show efficacy in clinical testing, despite success at the preclinical stages. This has highlighted the need for more effective translational outcome measures. EEG differences observed in FXS, including exaggerated N1 ERP amplitudes, increased resting gamma power and reduced gamma phase-locking in the sensory cortices, have been suggested as potential biomarkers of the syndrome. These abnormalities are thought to reflect cortical hyper excitability resulting from an excitatory (glutamate) and inhibitory (GABAergic) imbalance in FXS, which has been the target of several pharmaceutical remediation studies. EEG differences observed in humans also show similarities to those seen in laboratory models of FXS, which may allow for greater translational equivalence and better predict clinical success of putative therapeutics. There is some evidence from clinical trials showing that treatment related changes in EEG may be associated with clinical improvements, but these require replication and extension to other medications. Although the use of EEG characteristics as biomarkers is still in the early phases, and further research is needed to establish its utility in clinical trials, the current research is promising and signals the emergence of an effective translational biomarker.
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Affiliation(s)
- Aisling Kenny
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF, Edinburgh, UK.
| | - Damien Wright
- grid.4305.20000 0004 1936 7988Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF Edinburgh, UK
| | - Andrew C. Stanfield
- grid.4305.20000 0004 1936 7988Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, EH10 5HF Edinburgh, UK
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12
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Jiang S, He M, Xiao L, Sun Y, Ding J, Li W, Guo B, Wang L, Wang Y, Gao C, Sun T, Wang F. Prenatal GABAB Receptor Agonist Administration Corrects the Inheritance of Autism-Like Core Behaviors in Offspring of Mice Prenatally Exposed to Valproic Acid. Front Psychiatry 2022; 13:835993. [PMID: 35492716 PMCID: PMC9051083 DOI: 10.3389/fpsyt.2022.835993] [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: 12/15/2021] [Accepted: 03/07/2022] [Indexed: 12/21/2022] Open
Abstract
This study was performed to evaluate the effects of prenatal baclofen (a GABAB receptor agonist) treatment on the inheritance of autism-like behaviors in valproic acid (VPA)-exposed mice. VPA model mice (first generation, F1) that were prenatally exposed to VPA exhibited robust core autism-like behaviors, and we found that oral administration of baclofen to F1 mice corrected their autism-like behavioral phenotypes at an early age. Based on a previous epigenetics study, we mated the F1 male offspring with litter females to produce the second generation (F2). The F2 male mice showed obvious inheritance of autism-like phenotypes from F1 mice, implying the heritability of autism symptoms in patients with prenatal VPA exposure. Furthermore, we found prenatal baclofen administration was associated with beneficial effects on the autism-like phenotype in F2 male mice. This may have involved corrections in the density of total/mature dendritic spines in the hippocampus (HC) and medial prefrontal cortex (mPFC), normalizing synaptic plasticity. In this research, GABAB receptor agonist administration corrected the core autism-like behaviors of F1 mice and protected against the inheritance of neurodevelopmental disorders in the offspring of F1 mice, suggesting the potential of early intervention with GABAB receptor agonists in the treatment of neurodevelopmental disorders.
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Affiliation(s)
- Shucai Jiang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Maotao He
- School of Basic Medical Sciences, Weifang Medical University, Weifang, China
| | - Lifei Xiao
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Yu Sun
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Jiangwei Ding
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Wenchao Li
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Baorui Guo
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Lei Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Yangyang Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Caibin Gao
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Tao Sun
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Feng Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China.,The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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13
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Hagerman RJ, Hagerman PJ. Fragile X Syndrome: Lessons Learned and What New Treatment Avenues Are on the Horizon. Annu Rev Pharmacol Toxicol 2021; 62:365-381. [PMID: 34499526 DOI: 10.1146/annurev-pharmtox-052120-090147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and the leading single-gene form of autism spectrum disorder, encompassing cognitive, behavioral, and physical forms of clinical involvement. FXS is caused by large expansions of a noncoding CGG repeat (>200 repeats) in the FMR1 gene, at which point the gene is generally silenced. Absence of FMR1 protein (FMRP), important for synaptic development and maintenance, gives rise to the neurodevelopmental disorder. There is, at present, no therapeutic approach that directly reverses the loss of FMRP; however, there is an increasing number of potential treatments that target the pathways dysregulated in FXS, including those that address the enhanced activity of the mGluR5 pathway and deficits in GABA pathways. Based on studies of targeted therapeutics to date, the prospects are good for one or more effective therapies for FXS in the near future. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Randi J Hagerman
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, California 95817, USA; .,MIND Institute, University of California Davis Health, Sacramento, California 95817, USA
| | - Paul J Hagerman
- MIND Institute, University of California Davis Health, Sacramento, California 95817, USA.,Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, California 95616, USA;
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14
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Dionne O, Corbin F. An "Omic" Overview of Fragile X Syndrome. BIOLOGY 2021; 10:433. [PMID: 34068266 PMCID: PMC8153138 DOI: 10.3390/biology10050433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/01/2021] [Accepted: 05/08/2021] [Indexed: 01/16/2023]
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder associated with a wide range of cognitive, behavioral and medical problems. It arises from the silencing of the fragile X mental retardation 1 (FMR1) gene and, consequently, in the absence of its encoded protein, FMRP (fragile X mental retardation protein). FMRP is a ubiquitously expressed and multifunctional RNA-binding protein, primarily considered as a translational regulator. Pre-clinical studies of the past two decades have therefore focused on this function to relate FMRP's absence to the molecular mechanisms underlying FXS physiopathology. Based on these data, successful pharmacological strategies were developed to rescue fragile X phenotype in animal models. Unfortunately, these results did not translate into humans as clinical trials using same therapeutic approaches did not reach the expected outcomes. These failures highlight the need to put into perspective the different functions of FMRP in order to get a more comprehensive understanding of FXS pathophysiology. This work presents a review of FMRP's involvement on noteworthy molecular mechanisms that may ultimately contribute to various biochemical alterations composing the fragile X phenotype.
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Affiliation(s)
- Olivier Dionne
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke and Centre de Recherche du CHUS, CIUSSS de l’Estrie-CHUS, Sherbrooke, QC J1H 5H4, Canada;
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15
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Wilkinson CL, Nelson CA. Increased aperiodic gamma power in young boys with Fragile X Syndrome is associated with better language ability. Mol Autism 2021; 12:17. [PMID: 33632320 PMCID: PMC7908768 DOI: 10.1186/s13229-021-00425-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/16/2021] [Indexed: 02/17/2023] Open
Abstract
Background The lack of robust and reliable clinical biomarkers in Fragile X Syndrome (FXS), the most common inherited form of intellectual disability, has limited the successful translation of bench-to-bedside therapeutics. While numerous drugs have shown promise in reversing synaptic and behavioral phenotypes in mouse models of FXS, none have demonstrated clinical efficacy in humans. Electroencephalographic (EEG) measures have been identified as candidate biomarkers as EEG recordings of both adults with FXS and mouse models of FXS consistently exhibit alterations in resting state and task-related activity. However, the developmental timing of these EEG differences is not known as thus far EEG studies have not focused on young children with FXS. Further, understanding how EEG differences are associated with core symptoms of FXS is crucial to successful use of EEG as a biomarker, and may improve our understanding of the disorder. Methods Resting-state EEG was collected from FXS boys with full mutation of Fmr1 (2.5–7 years old, n = 11) and compared with both age-matched (n = 12) and cognitive-matched (n = 12) typically developing boys. Power spectra (including aperiodic and periodic components) were compared using non-parametric cluster-based permutation testing. Associations between 30 and 50 Hz gamma power and cognitive, language, and behavioral measures were evaluated using Pearson correlation and linear regression with age as a covariate. Results FXS participants showed increased power in the beta/gamma range (~ 25–50 Hz) across multiple brain regions. Both a reduction in the aperiodic (1/f) slope and increase in beta/gamma periodic activity contributed to the significant increase in high-frequency power. Increased gamma power, driven by the aperiodic component, was associated with better language ability in the FXS group. No association was observed between gamma power and parent report measures of behavioral challenges, sensory hypersensitivities, or adaptive behaviors. Limitations The study sample size was small, although comparable to other human studies in rare-genetic disorders. Findings are also limited to males in the age range studied. Conclusions Resting-state EEG measures from this study in young boys with FXS identified similar increases in gamma power previously reported in adults and mouse models. The observed positive association between resting state aperiodic gamma power and language development supports hypotheses that alterations in some EEG measures may reflect ongoing compensatory mechanisms. Supplementary Information The online version contains supplementary material available at 10.1186/s13229-021-00425-x.
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Affiliation(s)
- Carol L Wilkinson
- Division of Developmental Medicine, Boston Children's Hospital, 1 Autumn Street, 6th Floor, Boston, MA, 02115, USA.
| | - Charles A Nelson
- Division of Developmental Medicine, Boston Children's Hospital, 1 Autumn Street, 6th Floor, Boston, MA, 02115, USA
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16
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Pauly R, Ziats CA, Abenavoli L, Schwartz CE, Boccuto L. New Strategies for Clinical Trials in Autism Spectrum Disorder. Rev Recent Clin Trials 2020; 16:131-137. [PMID: 33222679 DOI: 10.2174/1574887115666201120093634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/10/2020] [Accepted: 10/22/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that poses several challenges in terms of clinical diagnosis and investigation of molecular etiology. The lack of knowledge on the pathogenic mechanisms underlying ASD has hampered the clinical trials that so far have tried to target ASD behavioral symptoms. In order to improve our understanding of the molecular abnormalities associated with ASD, a deeper and more extensive genetic profiling of targeted individuals with ASD was needed. METHODS The recent availability of new and more powerful sequencing technologies (third-generation sequencing) has allowed to develop novel strategies for the characterization of comprehensive genetic profiles of individuals with ASD. In particular, this review will describe integrated approaches based on the combination of various omics technologies that will lead to a better stratification of targeted cohorts for the design of clinical trials in ASD. RESULTS In order to analyze the big data collected by assays such as the whole genome, epigenome, transcriptome, and proteome, it is critical to develop an efficient computational infrastructure. Machine learning models are instrumental to identify non-linear relationships between the omics technologies and, therefore, establish a functional informative network among the different data sources. CONCLUSION The potential advantage provided by these new integrated omics-based strategies is better characterization of the genetic background of ASD cohorts, to identify novel molecular targets for drug development, and ultimately offer a more personalized approach in the design of clinical trials for ASD.
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Affiliation(s)
- Rini Pauly
- Greenwood Genetic Center, Greenwood, SC, United States
| | | | - Ludovico Abenavoli
- Department of Health Sciences, University "Magna Graecia", Catanzaro, Italy
| | | | - Luigi Boccuto
- Greenwood Genetic Center, Greenwood, SC, United States
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17
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Kordás K, Kis-Varga Á, Varga A, Eldering H, Bulthuis R, Lendvai B, Lévay G, Román V. Measuring sociability of mice using a novel three-chamber apparatus and algorithm of the LABORAS™ system. J Neurosci Methods 2020; 343:108841. [PMID: 32621917 DOI: 10.1016/j.jneumeth.2020.108841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND The social approach and social novelty tests utilizing the three-chamber apparatus are widely accepted to measure social behavior of rodents. The LABORAS™ system offers a possibility to assess sociability of mice in a reliable and objective manner. NEW METHOD We assessed the capability of the LABORAS™ sociability cage and algorithm (2.6.6) to detect social behaviors in mice. Furthermore, we investigated whether the system is able to detect various levels of sociability due to genetic background or after pharmacological treatments. RESULTS By comparing manual scoring with various detection zone settings of the automated registration, the most fitting algorithm with a detection zone radius of 90 mm was identified. When different strains were investigated, C57Bl/6 J and NMRI mice proved to be social, while CD1 mice were found asocial. The system was able to detect the sociability increasing effect of R-baclofen (0.5 mg/kg i.p.) and oxytocin (12 ng i.c.v.) in asocial CD1 mice. The negative control PCP impaired social behavior of C57Bl/6 J mice (1 mg/kg i.p.) and increased social avoidance in CD1 mice (0.3 mg/kg i.p.). COMPARISON WITH EXISTING METHOD(S) This setup, in contrast to video frame analysis softwares, determines signal changes caused by movements of rodents allowing accurate detection and analysis of trajectories. Parallel automated measurements also allow replacing time and labor intensive, highly subjective human observational work. CONCLUSIONS The set-up provides a fast and reliable method to examine social behavior of mice in the three-chamber apparatus. The system is capable of detecting pro or antisocial activity of pharmacological agents.
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Affiliation(s)
- Krisztina Kordás
- Pharmacology and Drug Safety Research, Gedeon Richter Plc, Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Ágnes Kis-Varga
- Pharmacology and Drug Safety Research, Gedeon Richter Plc, Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Anita Varga
- Pharmacology and Drug Safety Research, Gedeon Richter Plc, Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Herman Eldering
- Metris B.V., Kruisweg 829c, 2132NG Hoofddorp, the Netherlands
| | - Ronald Bulthuis
- Metris B.V., Kruisweg 829c, 2132NG Hoofddorp, the Netherlands
| | - Balázs Lendvai
- Pharmacology and Drug Safety Research, Gedeon Richter Plc, Gyömrői út 19-21, 1103 Budapest, Hungary
| | - György Lévay
- Pharmacology and Drug Safety Research, Gedeon Richter Plc, Gyömrői út 19-21, 1103 Budapest, Hungary
| | - Viktor Román
- Pharmacology and Drug Safety Research, Gedeon Richter Plc, Gyömrői út 19-21, 1103 Budapest, Hungary.
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18
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Bassetti D, Lombardi A, Kirischuk S, Luhmann HJ. Haploinsufficiency of Tsc2 Leads to Hyperexcitability of Medial Prefrontal Cortex via Weakening of Tonic GABAB Receptor-mediated Inhibition. Cereb Cortex 2020; 30:6313-6324. [PMID: 32705128 DOI: 10.1093/cercor/bhaa187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 12/30/2022] Open
Abstract
Loss-of-function mutation in one of the tumor suppressor genes TSC1 or TSC2 is associated with several neurological and psychiatric diseases, including autism spectrum disorders (ASDs). As an imbalance between excitatory and inhibitory neurotransmission, E/I ratio is believed to contribute to the development of these disorders, we investigated synaptic transmission during the first postnatal month using the Tsc2+/- mouse model. Electrophysiological recordings were performed in acute brain slices of medial prefrontal cortex. E/I ratio at postnatal day (P) 15-19 is increased in Tsc2+/- mice as compared with wildtype (WT). At P25-30, facilitated GABAergic transmission reduces E/I ratio to the WT level, but weakening of tonic GABAB receptor (GABABR)-mediated inhibition in Tsc2+/- mice leads to hyperexcitability both at single cell and neuronal network level. Short (1 h) preincubation of P25-30 Tsc2+/- slices with baclofen restores the GABABR-mediated inhibition and reduces network excitability. Interestingly, the same treatment at P15-19 leads to weakening of GABABR-mediated inhibition. We hypothesize that a dysfunction of tonic GABABR-mediated inhibition might contribute to the development of ASD symptoms and suggest that GABABR activation within an appropriate time window may be considered as a therapeutic target in ASD.
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Affiliation(s)
- Davide Bassetti
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
| | - Aniello Lombardi
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
| | - Sergei Kirischuk
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
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19
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Schmidt KC, Loutaev I, Quezado Z, Sheeler C, Smith CB. Regional rates of brain protein synthesis are unaltered in dexmedetomidine sedated young men with fragile X syndrome: A L-[1- 11C]leucine PET study. Neurobiol Dis 2020; 143:104978. [PMID: 32569795 PMCID: PMC7425798 DOI: 10.1016/j.nbd.2020.104978] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/01/2020] [Accepted: 06/15/2020] [Indexed: 02/06/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability. Fragile X mental retardation protein (FMRP), a putative translation suppressor, is absent or significantly reduced in FXS. One prevailing hypothesis is that rates of protein synthesis are increased by the absence of this regulatory protein. In accord with this hypothesis, we have previously reported increased rates of cerebral protein synthesis (rCPS) in the Fmr1 knockout mouse model of FXS and others have reported similar effects in hippocampal slices. To address the hypothesis in human subjects, we applied the L[1-11C]leucine PET method to measure rCPS in adults with FXS and healthy controls. All subjects were males between the ages of 18 and 24 years and free of psychotropic medication. As most fragile X participants were not able to undergo the PET study awake, we used dexmedetomidine for sedation during the imaging studies. We found no differences between rCPS measured during dexmedetomidine-sedation and the awake state in ten healthy controls. In the comparison of rCPS in dexmedetomidine-sedated fragile X participants (n = 9) and healthy controls (n = 14) we found no statistically significant differences. Our results from in vivo measurements in human brain do not support the hypothesis that rCPS are elevated due to the absence of FMRP. This hypothesis is based on findings in animal models and in vitro measurements in human peripheral cells. The absence of a translation suppressor may produce a more complex response in pathways regulating translation than previously thought. We may need to revise our working hypotheses regarding FXS and our thinking about potential therapeutics.
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Affiliation(s)
- Kathleen C Schmidt
- Section on Neuroadaptation and Protein Metabolism, National Institute of Mental Health, 10 Center Drive, Room 2D54, Bethesda, MD 20892-1298, United States of America
| | - Inna Loutaev
- Section on Neuroadaptation and Protein Metabolism, National Institute of Mental Health, 10 Center Drive, Room 2D54, Bethesda, MD 20892-1298, United States of America
| | - Zenaide Quezado
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892-1512, United States of America
| | - Carrie Sheeler
- Section on Neuroadaptation and Protein Metabolism, National Institute of Mental Health, 10 Center Drive, Room 2D54, Bethesda, MD 20892-1298, United States of America
| | - Carolyn Beebe Smith
- Section on Neuroadaptation and Protein Metabolism, National Institute of Mental Health, 10 Center Drive, Room 2D54, Bethesda, MD 20892-1298, United States of America.
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20
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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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21
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McCamphill PK, Stoppel LJ, Senter RK, Lewis MC, Heynen AJ, Stoppel DC, Sridhar V, Collins KA, Shi X, Pan JQ, Madison J, Cottrell JR, Huber KM, Scolnick EM, Holson EB, Wagner FF, Bear MF. Selective inhibition of glycogen synthase kinase 3α corrects pathophysiology in a mouse model of fragile X syndrome. Sci Transl Med 2020; 12:eaam8572. [PMID: 32434848 PMCID: PMC8095719 DOI: 10.1126/scitranslmed.aam8572] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 07/15/2019] [Accepted: 01/11/2020] [Indexed: 01/06/2023]
Abstract
Fragile X syndrome is caused by FMR1 gene silencing and loss of the encoded fragile X mental retardation protein (FMRP), which binds to mRNA and regulates translation. Studies in the Fmr1-/y mouse model of fragile X syndrome indicate that aberrant cerebral protein synthesis downstream of metabotropic glutamate receptor 5 (mGluR5) signaling contributes to disease pathogenesis, but clinical trials using mGluR5 inhibitors were not successful. Animal studies suggested that treatment with lithium might be an alternative approach. Targets of lithium include paralogs of glycogen synthase kinase 3 (GSK3), and nonselective small-molecule inhibitors of these enzymes improved disease phenotypes in a fragile X syndrome mouse model. However, the potential therapeutic use of GSK3 inhibitors has been hampered by toxicity arising from inhibition of both α and β paralogs. Recently, we developed GSK3 inhibitors with sufficient paralog selectivity to avoid a known toxic consequence of dual inhibition, that is, increased β-catenin stabilization. We show here that inhibition of GSK3α, but not GSK3β, corrected aberrant protein synthesis, audiogenic seizures, and sensory cortex hyperexcitability in Fmr1-/y mice. Although inhibiting either paralog prevented induction of NMDA receptor-dependent long-term depression (LTD) in the hippocampus, only inhibition of GSK3α impaired mGluR5-dependent and protein synthesis-dependent LTD. Inhibition of GSK3α additionally corrected deficits in learning and memory in Fmr1-/y mice; unlike mGluR5 inhibitors, there was no evidence of tachyphylaxis or enhanced psychotomimetic-induced hyperlocomotion. GSK3α selective inhibitors may have potential as a therapeutic approach for treating fragile X syndrome.
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Affiliation(s)
- Patrick K McCamphill
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Laura J Stoppel
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Rebecca K Senter
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Michael C Lewis
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Arnold J Heynen
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David C Stoppel
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Vinay Sridhar
- University of Texas Southwestern Medical Center, Department of Neuroscience, Dallas, TX 75390, USA
| | - Katie A Collins
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Xi Shi
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jen Q Pan
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jon Madison
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Kimberly M Huber
- University of Texas Southwestern Medical Center, Department of Neuroscience, Dallas, TX 75390, USA
| | - Edward M Scolnick
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Edward B Holson
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Florence F Wagner
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Mark F Bear
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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22
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Roberts TPL, Bloy L, Blaskey L, Kuschner E, Gaetz L, Anwar A, Ku M, Dipiero M, Bennett A, Edgar JC. A MEG Study of Acute Arbaclofen (STX-209) Administration. Front Integr Neurosci 2019; 13:69. [PMID: 31866839 PMCID: PMC6904329 DOI: 10.3389/fnint.2019.00069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/19/2019] [Indexed: 11/23/2022] Open
Abstract
Several electrophysiological parameters, including the auditory evoked response component M50/M100 latencies and the phase synchrony of transient and steady-state gamma-band oscillations have been implicated as atypical (to various extents) in autism spectrum disorder (ASD). Furthermore, some hypotheses suggest that an underlying neurobiological mechanism for these observations might be atypical local circuit function indexed by atypical levels of inhibitory neurotransmitter, GABA. This study was a randomized, placebo-controlled, double-blind, escalating-dose, acute investigation conducted in 25 14–18 year-old adolescents with ASD. The study assessed the sensitivity of magnetoencephalography (MEG) and MEGAPRESS “GABA” magnetic resonance spectroscopy (MRS) to monitor dose-dependent acute effects, as well as seeking to define properties of the pre-drug “baseline” electrophysiological and GABA signatures that might predict responsiveness to the GABA-B agonist, arbaclofen (STX-209). Overall, GABA levels and gamma-band oscillatory activity showed no acute changes at either low (15 mg) or high (30 mg) dose. Evoked M50 response latency measures tended to shorten (normalize), but there was heterogeneity across the group in M50 latency response, with only a subset of participants (n = 6) showing significant M50 latency shortening, and only at the 15 mg dose. Findings thus suggest that MEG M50 latency measures show acute effects of arbaclofen administration in select individuals, perhaps reflecting effective target engagement. Whether these subjects have a greater trend towards clinical benefit remains to be established. Finally, findings also provide preliminary support for the use of objective electrophysiological measures upon which to base inclusion for optimal enrichment of populations to be included in full-scale clinical trials of arbaclofen.
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Affiliation(s)
- Timothy P L Roberts
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Luke Bloy
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Lisa Blaskey
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Center for Autism Research, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Emily Kuschner
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Center for Autism Research, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Leah Gaetz
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Center for Autism Research, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Ayesha Anwar
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Center for Autism Research, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Matt Ku
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Marissa Dipiero
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Amanda Bennett
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - J Christopher Edgar
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Center for Autism Research, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
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23
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Baclofen as an adjuvant therapy for autism: a randomized, double-blind, placebo-controlled trial. Eur Child Adolesc Psychiatry 2019; 28:1619-1628. [PMID: 30980177 DOI: 10.1007/s00787-019-01333-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 04/03/2019] [Indexed: 10/27/2022]
Abstract
Increasing evidence suggests that the function of the GABAergic system is abnormally low in autism spectrum disorder (ASD). Baclofen, which functions as a selective agonist for GABAB receptors, does appear promising for the treatment of ASD. We conducted a 10-week randomized-controlled study aimed at evaluating the potential of baclofen as an adjuvant therapy to enhance the effect of risperidone in children with ASD. Sixty-four children (3-12 years) with moderate-to-severe irritability symptoms of ASD were included. We used the Aberrant Behavior Checklist-Community Edition (ABC-C) for the outcome measures on each of the follow-up visits (weeks 0, 5, and 10). Analysis of the combined data revealed significant improvement for all the ABC subscales (irritability: F = 51.644, df = 1.66, p < 0.001, lethargy: F = 39.734, df = 1.38, p < 0.001, stereotypic behavior: F = 25.495, df = 1.56, p < 0.001, hyperactivity: F = 54.135, df = 1.35, p < 0.001, and inappropriate speech: F = 19.277, df = 1.47, p = 0.004). Combined treatment with baclofen and risperidone exerted a greater effect on improvement of hyperactivity symptoms at both midpoint [Cohen's d, 95% confidence interval (CI) = - 3.14, - 5.56 to - 0.72] and endpoint (d, 95% CI = - 4.45, - 8.74 to - 0.16) when compared with treatment with placebo plus risperidone. The two treatments achieved comparable results for other outcome measures. Our data support safety and efficacy of baclofen as an adjuvant to risperidone for improvement of hyperactivity symptoms in children with ASD.
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Excitation/inhibition imbalance and impaired neurogenesis in neurodevelopmental and neurodegenerative disorders. Rev Neurosci 2019; 30:807-820. [DOI: 10.1515/revneuro-2019-0014] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/05/2019] [Indexed: 12/31/2022]
Abstract
AbstractThe excitation/inhibition (E/I) balance controls the synaptic inputs to prevent the inappropriate responses of neurons to input strength, and is required to restore the initial pattern of network activity. Various neurotransmitters affect synaptic plasticity within neural networks via the modulation of neuronal E/I balance in the developing and adult brain. Less is known about the role of E/I balance in the control of the development of the neural stem and progenitor cells in the course of neurogenesis and gliogenesis. Recent findings suggest that neural stem and progenitor cells appear to be the target for the action of GABA within the neurogenic or oligovascular niches. The same might be true for the role of neuropeptides (i.e. oxytocin) in neurogenic niches. This review covers current understanding of the role of E/I balance in the regulation of neuroplasticity associated with social behavior in normal brain, and in neurodevelopmental and neurodegenerative diseases. Further studies are required to decipher the GABA-mediated regulation of postnatal neurogenesis and synaptic integration of newly-born neurons as a potential target for the treatment of brain diseases.
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Port RG, Oberman LM, Roberts TPL. Revisiting the excitation/inhibition imbalance hypothesis of ASD through a clinical lens. Br J Radiol 2019; 92:20180944. [PMID: 31124710 PMCID: PMC6732925 DOI: 10.1259/bjr.20180944] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/19/2019] [Accepted: 05/21/2019] [Indexed: 12/22/2022] Open
Abstract
Autism spectrum disorder (ASD) currently affects 1 in 59 children, although the aetiology of this disorder remains unknown. Faced with multiple seemingly disparate and noncontiguous neurobiological alterations, Rubenstein and Merzenich hypothesized that imbalances between excitatory and inhibitory neurosignaling (E/I imbalance) underlie ASD. Since this initial statement, there has been a major focus examining this exact topic spanning both clinical and preclinical realms. The purpose of this article is to review the clinical neuroimaging literature surrounding E/I imbalance as an aetiology of ASD. Evidence for E/I imbalance is presented from several complementary clinical techniques including magnetic resonance spectroscopy, magnetoencephalography and transcranial magnetic stimulation. Additionally, two GABAergic potential interventions for ASD, which explicitly attempt to remediate E/I imbalance, are reviewed. The current literature suggests E/I imbalance as a useful framework for discussing the neurobiological etiology of ASD in at least a subset of affected individuals. While not constituting a completely unifying aetiology, E/I imbalance may be relevant as one of several underlying neuropathophysiologies that differentially affect individuals with ASD. Such statements do not diminish the value of the E/I imbalance concept-instead they suggest a possible role for the characterization of E/I imbalance, as well as other underlying neuropathophysiologies, in the biologically-based subtyping of individuals with ASD for potential applications including clinical trial enrichment as well as treatment triage.
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Affiliation(s)
| | - Lindsay M Oberman
- Center for Neuroscience and Regenerative Medicine, Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland
| | - Timothy PL Roberts
- Department of Radiology, Lurie Family Foundations MEG Imaging Center, Children’s Hospital of Philadelphia, Pennsylvania
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Cannabidiol (CBD) reduces anxiety-related behavior in mice via an FMRP-independent mechanism. Pharmacol Biochem Behav 2019; 181:93-100. [DOI: 10.1016/j.pbb.2019.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/21/2019] [Accepted: 05/01/2019] [Indexed: 11/18/2022]
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Zafarullah M, Tassone F. Molecular Biomarkers in Fragile X Syndrome. Brain Sci 2019; 9:E96. [PMID: 31035599 PMCID: PMC6562871 DOI: 10.3390/brainsci9050096] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 01/01/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited form of intellectual disability (ID) and a known monogenic cause of autism spectrum disorder (ASD). It is a trinucleotide repeat disorder, in which more than 200 CGG repeats in the 5' untranslated region (UTR) of the fragile X mental retardation 1 (FMR1) gene causes methylation of the promoter with consequent silencing of the gene, ultimately leading to the loss of the encoded fragile X mental retardation 1 protein, FMRP. FMRP is an RNA binding protein that plays a primary role as a repressor of translation of various mRNAs, many of which are involved in the maintenance and development of neuronal synaptic function and plasticity. In addition to intellectual disability, patients with FXS face several behavioral challenges, including anxiety, hyperactivity, seizures, repetitive behavior, and problems with executive and language performance. Currently, there is no cure or approved medication for the treatment of the underlying causes of FXS, but in the past few years, our knowledge about the proteins and pathways that are dysregulated by the loss of FMRP has increased, leading to clinical trials and to the path of developing molecular biomarkers for identifying potential targets for therapies. In this paper, we review candidate molecular biomarkers that have been identified in preclinical studies in the FXS mouse animal model and are now under validation for human applications or have already made their way to clinical trials.
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Affiliation(s)
- Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, 95817 CA, USA.
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, 95817 CA, USA.
- MIND Institute, University of California Davis Medical Center, Sacramento, 95817 CA, USA.
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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: 8] [Impact Index Per Article: 1.3] [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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Stoppel LJ, Kazdoba TM, Schaffler MD, Preza AR, Heynen A, Crawley JN, Bear MF. R-Baclofen Reverses Cognitive Deficits and Improves Social Interactions in Two Lines of 16p11.2 Deletion Mice. Neuropsychopharmacology 2018; 43:513-524. [PMID: 28984295 PMCID: PMC5770771 DOI: 10.1038/npp.2017.236] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/16/2017] [Accepted: 09/25/2017] [Indexed: 12/24/2022]
Abstract
Human chromosome 16p11.2 microdeletion is among the most common gene copy number variations (CNVs) known to confer risk for intellectual disability (ID) and autism spectrum disorder (ASD) and affects an estimated 3 in 10 000 people. Caused by a single copy deletion of ~27 genes, 16p11.2 microdeletion syndrome is characterized by ID, impaired language, communication and socialization skills, and ASD. Studies in animal models where a single copy of the syntenic 16p11.2 region has been deleted have revealed morphological, behavioral, and electrophysiological abnormalities. Previous studies suggested the possibility of some overlap in the mechanisms of pathophysiology in 16p11.2 microdeletion syndrome and fragile X syndrome. Improvements in fragile X phenotypes have been observed following chronic treatment with R-baclofen, a selective agonist of GABAB receptors. We were therefore motivated to investigate the effects of chronic oral R-baclofen administration in two independently generated mouse models of 16p11.2 microdeletion syndrome. In studies performed across two independent laboratories, we found that chronic activation of GABAB receptors improved performance on a series of cognitive and social tasks known to be impaired in two different 16p11.2 deletion mouse models. Our findings suggest that R-baclofen may have clinical utility for some of the core symptoms of human 16p11.2 microdeletion syndrome.
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Affiliation(s)
- Laura J Stoppel
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tatiana M Kazdoba
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Melanie D Schaffler
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Anthony R Preza
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Arnold Heynen
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jacqueline N Crawley
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Mark F Bear
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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Drug development for neurodevelopmental disorders: lessons learned from fragile X syndrome. Nat Rev Drug Discov 2017; 17:280-299. [PMID: 29217836 DOI: 10.1038/nrd.2017.221] [Citation(s) in RCA: 216] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neurodevelopmental disorders such as fragile X syndrome (FXS) result in lifelong cognitive and behavioural deficits and represent a major public health burden. FXS is the most frequent monogenic form of intellectual disability and autism, and the underlying pathophysiology linked to its causal gene, FMR1, has been the focus of intense research. Key alterations in synaptic function thought to underlie this neurodevelopmental disorder have been characterized and rescued in animal models of FXS using genetic and pharmacological approaches. These robust preclinical findings have led to the implementation of the most comprehensive drug development programme undertaken thus far for a genetically defined neurodevelopmental disorder, including phase IIb trials of metabotropic glutamate receptor 5 (mGluR5) antagonists and a phase III trial of a GABAB receptor agonist. However, none of the trials has been able to unambiguously demonstrate efficacy, and they have also highlighted the extent of the knowledge gaps in drug development for FXS and other neurodevelopmental disorders. In this Review, we examine potential issues in the previous studies and future directions for preclinical and clinical trials. FXS is at the forefront of efforts to develop drugs for neurodevelopmental disorders, and lessons learned in the process will also be important for such disorders.
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31
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Munshi K, Pawlowski K, Gonzalez-Heydrich J, Picker JD. Review of Salient Investigational Drugs for the Treatment of Fragile X Syndrome. J Child Adolesc Psychopharmacol 2017; 27:850-863. [PMID: 28475355 DOI: 10.1089/cap.2016.0200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVES Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability, in addition to being the commonest diagnosable cause of autism. The identification of the biochemical mechanism underlying this disorder has provided amenable targets for therapy. This review aims to provide an overview of investigational drug therapies for FXS. METHODS The authors carried out a search of clinical and preclinical trials for FXS in PubMed and on the U.S. National Institutes of Health index of clinical trials ( www.clinicaltrials.gov ). We limited our review to Phase II trials or more preliminary and reviewed the associated publications for these studies, complemented by a review of the literature on PubMed. RESULTS The review of the preclinical, Phase I, and Phase II trials of agents with therapeutic potential in FXS revolves around an understanding of the putative pathways in the pathogenesis of FXS. While there is significant overlap between some of these pathways, the agents can be categorized as modulators of the metabotropic glutamate receptor system, GABAergic agents, and miscellaneous modulators affecting other pathways. CONCLUSION As trials involving agents targeting different aspects of the molecular biology proceed, common themes have emerged. With the great hope came great disappointment as the initial trials failed to demonstrate sufficient significance. In particular, the differences in outcome between the animal models and humans have highlighted the unique challenges of carrying out trials in these cognitively and behaviorally challenged individuals, as well as a dearth of clinically relevant outcome measures for use in medication trials. However, in reviewing and reframing the studies of the last decade, many important lessons have been learned, which will ultimately have a greater impact on therapeutic research in the field of developmental delay as a whole.
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Affiliation(s)
- Kaizad Munshi
- 1 Department of Psychiatry, Boston Children's Hospital , Boston, Massachusetts.,2 Harvard Medical School , Boston, Massachusetts
| | - Katherine Pawlowski
- 3 Division of Genetics and Genomics, Boston Children's Hospital , Boston, Massachusetts.,4 Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital , Boston, Massachusetts
| | - Joseph Gonzalez-Heydrich
- 1 Department of Psychiatry, Boston Children's Hospital , Boston, Massachusetts.,2 Harvard Medical School , Boston, Massachusetts
| | - Jonathan D Picker
- 1 Department of Psychiatry, Boston Children's Hospital , Boston, Massachusetts.,2 Harvard Medical School , Boston, Massachusetts.,3 Division of Genetics and Genomics, Boston Children's Hospital , Boston, Massachusetts
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Ceolin L, Bouquier N, Vitre-Boubaker J, Rialle S, Severac D, Valjent E, Perroy J, Puighermanal E. Cell Type-Specific mRNA Dysregulation in Hippocampal CA1 Pyramidal Neurons of the Fragile X Syndrome Mouse Model. Front Mol Neurosci 2017; 10:340. [PMID: 29104533 PMCID: PMC5655025 DOI: 10.3389/fnmol.2017.00340] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/06/2017] [Indexed: 12/19/2022] Open
Abstract
Fragile X syndrome (FXS) is a genetic disorder due to the silencing of the Fmr1 gene, causing intellectual disability, seizures, hyperactivity, and social anxiety. All these symptoms result from the loss of expression of the RNA binding protein fragile X mental retardation protein (FMRP), which alters the neurodevelopmental program to abnormal wiring of specific circuits. Aberrant mRNAs translation associated with the loss of Fmr1 product is widely suspected to be in part the cause of FXS. However, precise gene expression changes involved in this disorder have yet to be defined. The objective of this study was to identify the set of mistranslated mRNAs that could contribute to neurological deficits in FXS. We used the RiboTag approach and RNA sequencing to provide an exhaustive listing of genes whose mRNAs are differentially translated in hippocampal CA1 pyramidal neurons as the integrative result of FMRP loss and subsequent neurodevelopmental adaptations. Among genes differentially regulated between adult WT and Fmr1-/y mice, we found enrichment in FMRP-binders but also a majority of non-FMRP-binders. Interestingly, both up- and down-regulation of specific gene expression is relevant to fully understand the molecular deficiencies triggering FXS. More importantly, functional genomic analysis highlighted the importance of genes involved in neuronal connectivity. Among them, we show that Klk8 altered expression participates in the abnormal hippocampal dendritic spine maturation observed in a mouse model of FXS.
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Affiliation(s)
- Laura Ceolin
- IGF, CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | | | | | | | - Dany Severac
- Montpellier GenomiX c/o IGF, Montpellier, France
| | | | - Julie Perroy
- IGF, CNRS, INSERM, Univ. Montpellier, Montpellier, France
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Developmental Disruption of GABA AR-Meditated Inhibition in Cntnap2 KO Mice. eNeuro 2017; 4:eN-NWR-0162-17. [PMID: 28966979 PMCID: PMC5617210 DOI: 10.1523/eneuro.0162-17.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 12/24/2022] Open
Abstract
GABA released from presynaptic sites induces short-lived phasic inhibition mediated by synaptic GABAA receptors (GABAARs) and longer-duration tonic inhibition mediated by extrasynaptic GABAA or GABAB receptors (GABABRs). A number of studies have found that contactin-associated protein 2 (Cntnap2) knockout (KO) mice, a well-established mouse model of autism, exhibit reduced interneuron numbers and aberrant phasic inhibition. However, little is known about whether tonic inhibition is disrupted in Cntnap2 KO mice and when the disruption of inhibition begins to occur during postnatal development. We examined tonic and phasic inhibition in layer 2/3 pyramidal cells of primary visual cortex of Cntnap2 KO at two different developmental stages, three to four and six to eight weeks of age. We found that both phasic inhibition and GABAAR but not GABABR-mediated tonic inhibition was reduced in pyramidal cells from six- to eight-week-old Cntnap2 KO mice, while in three- to four-week-old mice, no significant effects of genotype on tonic or phasic inhibition was observed. We further found that activation of tonic currents mediated by δ-subunit-containing GABAARs reduced neural excitability, an effect that was attenuated by loss of Cntnap2. While the relative contribution of tonic versus phasic inhibition to autism-related symptoms remains unclear, our data suggest that reduced tonic inhibition may play an important role, and δ-subunit-containing GABAARs may be a useful target for therapeutic intervention in autism.
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Saré RM, Harkless L, Levine M, Torossian A, Sheeler CA, Smith CB. Deficient Sleep in Mouse Models of Fragile X Syndrome. Front Mol Neurosci 2017; 10:280. [PMID: 28919851 PMCID: PMC5585179 DOI: 10.3389/fnmol.2017.00280] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/18/2017] [Indexed: 12/01/2022] Open
Abstract
In patients with fragile X syndrome (FXS), sleep problems are commonly observed but are not well characterized. In animal models of FXS (dfmr1 and Fmr1 knockout (KO)/Fxr2 heterozygote) circadian rhythmicity is affected, but sleep per se has not been examined. We used a home-cage monitoring system to assess total sleep time in both light and dark phases in Fmr1 KO mice at different developmental stages. Fmr1 KOs at P21 do not differ from controls, but genotype × phase interactions in both adult (P70 and P180) groups are statistically significant indicating that sleep in Fmr1 KOs is reduced selectively in the light phase compared to controls. Our results show the emergence of abnormal sleep in Fmr1 KOs during the later stages of brain maturation. Treatment of adult Fmr1 KO mice with a GABAB agonist, R-baclofen, did not restore sleep duration in the light phase. In adult (P70) Fmr1 KO/Fxr2 heterozygote animals, total sleep time was further reduced, once again in the light phase. Our data highlight the importance of the fragile X genes (Fmr1 and Fxr2) in sleep physiology and confirm the utility of these mouse models in enhancing our understanding of sleep disorders in FXS.
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Affiliation(s)
- R Michelle Saré
- Section on Neuroadaptation and Protein Metabolism, Department of Health and Human Services, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, United States
| | - Lee Harkless
- Section on Neuroadaptation and Protein Metabolism, Department of Health and Human Services, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, United States
| | - Merlin Levine
- Section on Neuroadaptation and Protein Metabolism, Department of Health and Human Services, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, United States
| | - Anita Torossian
- Section on Neuroadaptation and Protein Metabolism, Department of Health and Human Services, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, United States
| | - Carrie A Sheeler
- Section on Neuroadaptation and Protein Metabolism, Department of Health and Human Services, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, United States
| | - Carolyn B Smith
- Section on Neuroadaptation and Protein Metabolism, Department of Health and Human Services, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, United States
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Borrie SC, Brems H, Legius E, Bagni C. Cognitive Dysfunctions in Intellectual Disabilities: The Contributions of the Ras-MAPK and PI3K-AKT-mTOR Pathways. Annu Rev Genomics Hum Genet 2017; 18:115-142. [DOI: 10.1146/annurev-genom-091416-035332] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sarah C. Borrie
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Hilde Brems
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Eric Legius
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Claudia Bagni
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
- Department of Fundamental Neuroscience, University of Lausanne, 1005 Lausanne, Switzerland
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00173 Rome, Italy
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Rogers TD, Anacker AMJ, Kerr TM, Forsberg CG, Wang J, Zhang B, Veenstra-VanderWeele J. Effects of a social stimulus on gene expression in a mouse model of fragile X syndrome. Mol Autism 2017. [PMID: 28649315 PMCID: PMC5481916 DOI: 10.1186/s13229-017-0148-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND People with fragile X syndrome (FXS) often have deficits in social behavior, and a substantial portion meet criteria for autism spectrum disorder. Though the genetic cause of FXS is known to be due to the silencing of FMR1, and the Fmr1 null mouse model representing this lesion has been extensively studied, the contributions of this gene and its protein product, FMRP, to social behavior are not well understood. METHODS Fmr1 null mice and wildtype littermates were exposed to a social or non-social stimulus. In one experiment, subjects were assessed for expression of the inducible transcription factor c-Fos in response to the stimulus, to detect brain regions with social-specific activity. In a separate experiment, tissue was taken from those brain regions showing differential activity, and RNA sequencing was performed. RESULTS Immunohistochemistry revealed a significantly greater number of c-Fos-positive cells in the lateral amygdala and medial amygdala in the brains of mice exposed to a social stimulus, compared to a non-social stimulus. In the prelimbic cortex, there was no significant effect of social stimulus; although the number of c-Fos-positive cells was lower in the social condition compared to the non-social condition, and negatively correlated with c-Fos in the amygdala. RNA sequencing revealed differentially expressed genes enriched for molecules known to interact with FMRP and also for autism-related genes identified in the Simons Foundation Autism Research Initiative gene database. Ingenuity Pathway Analysis detected enrichment of differentially expressed genes in networks and pathways related to neuronal development, intracellular signaling, and inflammatory response. CONCLUSIONS Using the Fmr1 null mouse model of fragile X syndrome, we have identified brain regions, gene networks, and molecular pathways responsive to a social stimulus. These findings, and future experiments following up on the role of specific gene networks, may shed light on the neural mechanisms underlying dysregulated social behaviors in fragile X syndrome and more broadly.
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Affiliation(s)
- Tiffany D Rogers
- Department of Psychiatry, Vanderbilt University, 7158 MRBIII, 465 21st Avenue South, Nashville, TN 37232 USA.,Department of Psychology, Middle Tennessee State University, 355 Jones Hall, 624 Old Main Circle, Murfreesboro, TN 37132 USA
| | - Allison M J Anacker
- Department of Psychiatry, Columbia University; New York State Psychiatric Institute, 1051 Riverside Dr, Unit 78, New York, NY 10032 USA
| | - Travis M Kerr
- The University of Tennessee Health Science Center College of Medicine, 910 Madison Ave, Suite 1002, Memphis, TN 38163 USA
| | - C Gunnar Forsberg
- College of Medicine, Medical University of South Carolina, Charleston, SC 29425 USA
| | - Jing Wang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030 USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Bing Zhang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030 USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Jeremy Veenstra-VanderWeele
- Department of Psychiatry, Columbia University; New York State Psychiatric Institute, 1051 Riverside Dr, Unit 78, New York, NY 10032 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: 109] [Impact Index Per Article: 15.6] [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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38
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Arbaclofen in Children and Adolescents with Autism Spectrum Disorder: A Randomized, Controlled, Phase 2 Trial. Neuropsychopharmacology 2017; 42:1390-1398. [PMID: 27748740 PMCID: PMC5436109 DOI: 10.1038/npp.2016.237] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/05/2016] [Accepted: 10/12/2016] [Indexed: 12/11/2022]
Abstract
Several lines of emerging data point to an imbalance between neuronal excitation and inhibition in at least a subgroup of individuals with autism spectrum disorder (ASD), including in those with fragile X syndrome (FXS), one of the most common genetic syndromes within ASD. In animal models of FXS and of ASD, GABA-B agonists have improved both brain and behavioral phenotypes, including social behavior. A phase 2 randomized, placebo-controlled, crossover trial found that the GABA-B agonist arbaclofen improved social avoidance symptoms in FXS. A pilot open-label trial of arbaclofen suggested similar benefits in ASD. We therefore evaluated arbaclofen in a randomized, placebo-controlled, phase 2 study of 150 participants, aged 5-21 years, with ASD. No difference from placebo was detected on the primary outcome measure, the parent-rated Aberrant Behavior Checklist Social Withdrawal/Lethargy subscale. However, a specified secondary analysis found improvement on the clinician-rated Clinical Global Impression of Severity. An exploratory post hoc analysis of participants with a consistent rater across the trial revealed greater improvement in the Vineland Adaptive Behavior Scales II socialization domain in participants receiving arbaclofen. Affect lability (11%) and sedation (9%) were the most common adverse events. In this exploratory study, secondary analyses suggest that arbaclofen may have the potential to improve symptoms in some children with ASD, but further study will be needed to replicate and extend these initial findings.
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Sinclair D, Featherstone R, Naschek M, Nam J, Du A, Wright S, Pance K, Melnychenko O, Weger R, Akuzawa S, Matsumoto M, Siegel SJ. GABA-B Agonist Baclofen Normalizes Auditory-Evoked Neural Oscillations and Behavioral Deficits in the Fmr1 Knockout Mouse Model of Fragile X Syndrome. eNeuro 2017; 4:ENEURO.0380-16.2017. [PMID: 28451631 PMCID: PMC5394929 DOI: 10.1523/eneuro.0380-16.2017] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/09/2017] [Accepted: 02/13/2017] [Indexed: 12/15/2022] Open
Abstract
Fragile X syndrome is a genetic condition resulting from FMR1 gene mutation that leads to intellectual disability, autism-like symptoms, and sensory hypersensitivity. Arbaclofen, a GABA-B agonist, has shown efficacy in some individuals with FXS but has become unavailable after unsuccessful clinical trials, prompting interest in publicly available, racemic baclofen. The present study investigated whether racemic baclofen can remediate abnormalities of neural circuit function, sensory processing, and behavior in Fmr1 knockout mice, a rodent model of fragile X syndrome. Fmr1 knockout mice showed increased baseline and auditory-evoked high-frequency gamma (30-80 Hz) power relative to C57BL/6 controls, as measured by electroencephalography. These deficits were accompanied by decreased T maze spontaneous alternation, decreased social interactions, and increased open field center time, suggestive of diminished working memory, sociability, and anxiety-like behavior, respectively. Abnormal auditory-evoked gamma oscillations, working memory, and anxiety-related behavior were normalized by treatment with baclofen, but impaired sociability was not. Improvements in working memory were evident predominantly in mice whose auditory-evoked gamma oscillations were dampened by baclofen. These findings suggest that racemic baclofen may be useful for targeting sensory and cognitive disturbances in fragile X syndrome.
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Affiliation(s)
- D Sinclair
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - R Featherstone
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M Naschek
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - J Nam
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A Du
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - S Wright
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - K Pance
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - O Melnychenko
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - R Weger
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - S Akuzawa
- Neuroscience Research Unit, DDR, Astellas Pharma Inc., Tsukuba-Shi, Ibaraki 305-8585, Japan
| | - M Matsumoto
- Neuroscience Research Unit, DDR, Astellas Pharma Inc., Tsukuba-Shi, Ibaraki 305-8585, Japan
| | - S J Siegel
- Translational Neuroscience Program Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
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FMRP regulates an ethanol-dependent shift in GABA BR function and expression with rapid antidepressant properties. Nat Commun 2016; 7:12867. [PMID: 27666021 PMCID: PMC5052688 DOI: 10.1038/ncomms12867] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/08/2016] [Indexed: 12/17/2022] Open
Abstract
Alcohol promotes lasting neuroadaptive changes that may provide relief from depressive symptoms, often referred to as the self-medication hypothesis. However, the molecular/synaptic pathways that are shared by alcohol and antidepressants are unknown. In the current study, acute exposure to ethanol produced lasting antidepressant and anxiolytic behaviours. To understand the functional basis of these behaviours, we examined a molecular pathway that is activated by rapid antidepressants. Ethanol, like rapid antidepressants, alters γ-aminobutyric acid type B receptor (GABABR) expression and signalling, to increase dendritic calcium. Furthermore, new GABABRs are synthesized in response to ethanol treatment, requiring fragile-X mental retardation protein (FMRP). Ethanol-dependent changes in GABABR expression, dendritic signalling, and antidepressant efficacy are absent in Fmr1-knockout (KO) mice. These findings indicate that FMRP is an important regulator of protein synthesis following alcohol exposure, providing a molecular basis for the antidepressant efficacy of acute ethanol exposure. Alcohol is thought to lead to neuroadaptive changes, although the underlying molecular mechanisms are unclear. Here, the authors find ethanol treatment alters GABAB-receptor expression via fragile-X mental retardation protein in mice, leading to antidepressant-like behaviours.
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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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Beas BS, Setlow B, Bizon JL. Effects of acute administration of the GABA(B) receptor agonist baclofen on behavioral flexibility in rats. Psychopharmacology (Berl) 2016; 233:2787-97. [PMID: 27256354 PMCID: PMC4919234 DOI: 10.1007/s00213-016-4321-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 05/09/2016] [Indexed: 12/20/2022]
Abstract
RATIONALE The ability to adjust response strategies when faced with changes in the environment is critical for normal adaptive behavior. Such behavioral flexibility is compromised by experimental disruption of cortical GABAergic signaling, as well as in conditions such as schizophrenia and normal aging that are characterized by cortical hyperexcitability. The current studies were designed to determine whether stimulation of GABAergic signaling using the GABA(B) receptor agonist baclofen can facilitate behavioral flexibility. METHODS Male Fischer 344 rats were trained in a set-shifting task in which they learned to discriminate between two response levers to obtain a food reward. Correct levers were signaled in accordance with two distinct response rules (rule 1: correct lever signaled by a cue light; rule 2: correct lever signaled by its left/right position). The order of rule presentation varied, but they were always presented sequentially, with the trials and errors to reach criterion performance on the second (set shift) rule providing the measure of behavioral flexibility. Experiments determined the effects of the GABA(B) receptor agonist baclofen (intraperitoneal, 0, 1.0, 2.5, and 4.0 mg/kg) administered acutely before the shift to the second rule. RESULTS Baclofen enhanced set-shifting performance. Control experiments demonstrated that this enhancement was not simply due to improved discrimination learning, nor was it due to impaired recall of the initial discrimination rule. CONCLUSIONS The results demonstrate that baclofen can facilitate behavioral flexibility, suggesting that GABA(B) receptor agonists may have utility for treating behavioral dysfunction in neuropsychiatric disorders.
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Affiliation(s)
- B. Sofia Beas
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL
| | - Barry Setlow
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL,Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL
| | - Jennifer L. Bizon
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL,Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL
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Behavioral Phenotype of Fmr1 Knock-Out Mice during Active Phase in an Altered Light/Dark Cycle. eNeuro 2016; 3:eN-NWR-0035-16. [PMID: 27294193 PMCID: PMC4901146 DOI: 10.1523/eneuro.0035-16.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 03/14/2016] [Accepted: 03/26/2016] [Indexed: 12/14/2022] Open
Abstract
Fragile X syndrome (FXS) is the most commonly inherited form of intellectual disability and is a disorder that is also highly associated with autism. FXS occurs as a result of an expanded CGG repeat sequence leading to transcriptional silencing. In an animal model of FXS in which Fmr1 is knocked out (Fmr1 KO), many physical, physiological, and behavioral characteristics of the human disease are recapitulated. Prior characterization of the mouse model was conducted during the day, the inactive phase of the circadian cycle. Circadian rhythms are an important contributor to behavior and may play a role in the study of disease phenotype. Moreover, changes in the parameters of circadian rhythm are known to occur in FXS animal models. We conducted an investigation of key behavioral phenotypes in Fmr1 KO mice during their active phase. We report that phase did not alter the Fmr1 KO phenotype in open field activity, anxiety, and learning and memory. There was a slight effect of phase on social behavior as measured by time in chamber, but not by time spent sniffing. Our data strengthen the existing data characterizing the phenotype of Fmr1 KO mice, indicating that it is independent of circadian phase.
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