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Medishetti R, Rani R, Kavati S, Mahilkar A, Akella V, Saxena U, Kulkarni P, Sevilimedu A. A DNAzyme based knockdown model for Fragile-X syndrome in zebrafish reveals a critical window for therapeutic intervention. J Pharmacol Toxicol Methods 2019; 101:106656. [PMID: 31734279 DOI: 10.1016/j.vascn.2019.106656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 11/05/2019] [Accepted: 11/10/2019] [Indexed: 11/16/2022]
Abstract
INTRODUCTION FXS is the leading cause of intellectual disabilities in males and a major monogenic cause of ASD (Autism spectrum disorders). It occurs due to the loss of FMRP, whose role in early development is not well understood. In this study, we have used a novel DNAzyme based approach to create a larval model of FXS in zebrafish with specific focus on the early developmental window. METHODS Fmr1specific DNAzymes were electroporated into embryos to create the knockdown. Changes in RNA and protein levels of FMRP and relevant biomarkers were measured in the 0-7dpf window. Behavioral tests to measure anxiety, cognitive impairments and irritability in the larvae were conducted at the 7dpf stage. Drug treatment was carried out at various time points in the 0-7dpf window to identify the critical window for pharmacological intervention. RESULTS The DNAzyme based knockdown approach led to a significant knockdown of FMRP in the zebrafish embryos, accompanied by increased anxiety, irritability and cognitive impairments at 7dpf, thus creating a robust larval model of FXS. Treatment with the Mavoglurant was able to rescue the behavioral phenotypes in the FXS larvae, and found to be more efficacious in the 0-3dpf window. DISCUSSION The results from this study have revealed that a) a DNAzyme based knockdown approach can be used to create robust larval zebrafish model of disease, in a high-throughput manner and b) optimal window for therapeutic intervention for FXS as well as other pediatric diseases with a monogenic cause can be identified using such a model.
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Affiliation(s)
- Raghavender Medishetti
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Rita Rani
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Srinivas Kavati
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Anjali Mahilkar
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Venkateswarlu Akella
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Uday Saxena
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Pushkar Kulkarni
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India.
| | - Aarti Sevilimedu
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India.
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Crespi BJ. Comparative psychopharmacology of autism and psychotic-affective disorders suggests new targets for treatment. Evol Med Public Health 2019; 2019:149-168. [PMID: 31548888 PMCID: PMC6748779 DOI: 10.1093/emph/eoz022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/07/2019] [Indexed: 12/13/2022] Open
Abstract
The first treatments showing effectiveness for some psychiatric disorders, such as lithium for bipolar disorder and chlorpromazine for schizophrenia, were discovered by accident. Currently, psychiatric drug design is seen as a scientific enterprise, limited though it remains by the complexity of brain development and function. Relatively few novel and effective drugs have, however, been developed for many years. The purpose of this article is to demonstrate how evolutionary biology can provide a useful framework for psychiatric drug development. The framework is based on a diametrical nature of autism, compared with psychotic-affective disorders (mainly schizophrenia, bipolar disorder and depression). This paradigm follows from two inferences: (i) risks and phenotypes of human psychiatric disorders derive from phenotypes that have evolved along the human lineage and (ii) biological variation is bidirectional (e.g. higher vs lower, faster vs slower, etc.), such that dysregulation of psychological traits varies in two opposite ways. In this context, the author review the evidence salient to the hypothesis that autism and psychotic-affective disorders represent diametrical disorders in terms of current, proposed and potential psychopharmacological treatments. Studies of brain-derived neurotrophic factor, the PI3K pathway, the NMDA receptor, kynurenic acid metabolism, agmatine metabolism, levels of the endocannabinoid anandamide, antidepressants, anticonvulsants, antipsychotics, and other treatments, demonstrate evidence of diametric effects in autism spectrum disorders and phenotypes compared with psychotic-affective disorders and phenotypes. These findings yield insights into treatment mechanisms and the development of new pharmacological therapies, as well as providing an explanation for the longstanding puzzle of antagonism between epilepsy and psychosis. Lay Summary: Consideration of autism and schizophrenia as caused by opposite alterations to brain development and function leads to novel suggestions for pharmacological treatments.
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Affiliation(s)
- Bernard J Crespi
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder that causes intellectual disability. It is a leading known genetic cause of autism. In addition to cognitive, social, and communication deficits, humans with FXS demonstrate abnormal sensory processing including sensory hypersensitivity. Sensory hypersensitivity commonly manifests as auditory, tactile, or visual defensiveness or avoidance. Clinical, behavioral, and electrophysiological studies consistently show auditory hypersensitivity, impaired habituation to repeated sounds, and reduced auditory attention in humans with FXS. Children with FXS also exhibit significant visuospatial impairments. Studies in infants and toddlers with FXS have documented impairments in processing texture-defined motion stimuli, temporal flicker, perceiving ordinal numerical sequence, and the ability to maintain the identity of dynamic object information during occlusion. Consistent with the observations in humans with FXS, fragile X mental retardation 1 ( Fmr1) gene knockout (KO) rodent models of FXS also show seizures, abnormal visual-evoked responses, auditory hypersensitivity, and abnormal processing at multiple levels of the auditory system, including altered acoustic startle responses. Among other sensory symptoms, individuals with FXS exhibit tactile defensiveness. Fmr1 KO mice also show impaired encoding of tactile stimulation frequency and larger size of receptive fields in the somatosensory cortex. Since sensory deficits are relatively more tractable from circuit mechanisms and developmental perspectives than more complex social behaviors, the focus of this review is on clinical, functional, and structural studies that outline the auditory, visual, and somatosensory processing deficits in FXS. The similarities in sensory phenotypes between humans with FXS and animal models suggest a likely conservation of basic sensory processing circuits across species and may provide a translational platform to not just develop biomarkers but also to understand underlying mechanisms. We argue that preclinical studies in animal models of FXS can facilitate the ongoing search for new therapeutic approaches in FXS by understanding mechanisms of basic sensory processing circuits and behaviors that are conserved across species.
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Affiliation(s)
- Maham Rais
- 1 Division of Biomedical Sciences, University of California Riverside School of Medicine, CA, USA.,2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA
| | - Devin K Binder
- 1 Division of Biomedical Sciences, University of California Riverside School of Medicine, CA, USA.,2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA.,3 Neuroscience Graduate Program, University of California Riverside, CA, USA
| | - Khaleel A Razak
- 2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA.,3 Neuroscience Graduate Program, University of California Riverside, CA, USA.,4 Psychology Department, University of California Riverside, CA, USA
| | - Iryna M Ethell
- 1 Division of Biomedical Sciences, University of California Riverside School of Medicine, CA, USA.,2 Biomedical Sciences Graduate Program, University of California Riverside, CA, USA.,3 Neuroscience Graduate Program, University of California Riverside, CA, USA
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Lovastatin, not Simvastatin, Corrects Core Phenotypes in the Fragile X Mouse Model. eNeuro 2019; 6:ENEURO.0097-19.2019. [PMID: 31147392 PMCID: PMC6565377 DOI: 10.1523/eneuro.0097-19.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/11/2019] [Accepted: 05/13/2019] [Indexed: 02/07/2023] Open
Abstract
The cholesterol-lowering drug lovastatin corrects neurological phenotypes in animal models of fragile X syndrome (FX), a commonly identified genetic cause of autism and intellectual disability (ID). The therapeutic efficacy of lovastatin is being tested in clinical trials for FX; however, the structurally similar drug simvastatin has been proposed as an alternative due to an increased potency and brain penetrance. Here, we perform a side-by-side comparison of the effects of lovastatin and simvastatin treatment on two core phenotypes in Fmr1-/y mice versus WT littermates: excessive hippocampal protein synthesis and susceptibility to audiogenic seizures (AGSs). We find that simvastatin does not correct excessive hippocampal protein synthesis in the Fmr1-/y hippocampus at any dose tested. In fact, simvastatin significantly increases protein synthesis in both Fmr1-/y and WT. Moreover, injection of simvastatin does not reduce AGS in the Fmr1-/y mouse, while lovastatin significantly reduces AGS incidence and severity versus vehicle-treated animals. These results show that unlike lovastatin, simvastatin does not correct core phenotypes in the Fmr1-/y mouse model.
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Bodaleo F, Tapia-Monsalves C, Cea-Del Rio C, Gonzalez-Billault C, Nunez-Parra A. Structural and Functional Abnormalities in the Olfactory System of Fragile X Syndrome Models. Front Mol Neurosci 2019; 12:135. [PMID: 31191246 PMCID: PMC6548058 DOI: 10.3389/fnmol.2019.00135] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 12/18/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited form of intellectual disability. It is produced by mutation of the Fmr1 gene that encodes for the Fragile Mental Retardation Protein (FMRP), an important RNA-binding protein that regulates the expression of multiple proteins located in neuronal synapses. Individuals with FXS exhibit abnormal sensory information processing frequently leading to hypersensitivity across sensory modalities and consequently a wide array of behavioral symptoms. Insects and mammals engage primarily their sense of smell to create proper representations of the external world and guide adequate decision-making processes. This feature in combination with the exquisitely organized neuronal circuits found throughout the olfactory system (OS) and the wide expression of FMRP in brain regions that process olfactory information makes it an ideal model to study sensory alterations in FXS models. In the last decade several groups have taken advantage of these features and have used the OS of fruit fly and rodents to understand neuronal alteration giving rise to sensory perception issues. In this review article, we will discuss molecular, morphological and physiological aspects of the olfactory information processing in FXS models. We will highlight the decreased inhibitory/excitatory synaptic balance and the diminished synaptic plasticity found in this system resulting in behavioral alteration of individuals in the presence of odorant stimuli.
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Affiliation(s)
- Felipe Bodaleo
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile
| | | | - Christian Cea-Del Rio
- Laboratory of Neurophysiopathology, Centro de Investigacion Biomedica y Aplicada (CIBAP), School of Medicine, Universidad de Santiago de Chile, Santiago, Chile
| | - Christian Gonzalez-Billault
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile.,The Buck Institute for Research on Aging, Novato, CA, United States
| | - Alexia Nunez-Parra
- Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Cell Physiology Center, Universidad de Chile, Santiago, Chile
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56
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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: 19] [Impact Index Per Article: 3.8] [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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Drozd HP, Karathanasis SF, Molosh AI, Lukkes JL, Clapp DW, Shekhar A. From bedside to bench and back: Translating ASD models. PROGRESS IN BRAIN RESEARCH 2018; 241:113-158. [PMID: 30447753 DOI: 10.1016/bs.pbr.2018.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autism spectrum disorders (ASD) represent a heterogeneous group of disorders defined by deficits in social interaction/communication and restricted interests, behaviors, or activities. Models of ASD, developed based on clinical data and observations, are used in basic science, the "bench," to better understand the pathophysiology of ASD and provide therapeutic options for patients in the clinic, the "bedside." Translational medicine creates a bridge between the bench and bedside that allows for clinical and basic science discoveries to challenge one another to improve the opportunities to bring novel therapies to patients. From the clinical side, biomarker work is expanding our understanding of possible mechanisms of ASD through measures of behavior, genetics, imaging modalities, and serum markers. These biomarkers could help to subclassify patients with ASD in order to better target treatments to a more homogeneous groups of patients most likely to respond to a candidate therapy. In turn, basic science has been responding to developments in clinical evaluation by improving bench models to mechanistically and phenotypically recapitulate the ASD phenotypes observed in clinic. While genetic models are identifying novel therapeutics targets at the bench, the clinical efforts are making progress by defining better outcome measures that are most representative of meaningful patient responses. In this review, we discuss some of these challenges in translational research in ASD and strategies for the bench and bedside to bridge the gap to achieve better benefits to patients.
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Affiliation(s)
- Hayley P Drozd
- Program in Medical Neurobiology, Stark Neurosciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Sotirios F Karathanasis
- Program in Medical Neurobiology, Stark Neurosciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Andrei I Molosh
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Jodi L Lukkes
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - D Wade Clapp
- Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Anantha Shekhar
- Program in Medical Neurobiology, Stark Neurosciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States; Indiana Clinical and Translation Sciences Institute, Indiana University School of Medicine, Indianapolis, IN, United States.
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58
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Lundbye CJ, Toft AKH, Banke TG. Inhibition of GluN2A NMDA receptors ameliorates synaptic plasticity deficits in the Fmr1 -/y mouse model. J Physiol 2018; 596:5017-5031. [PMID: 30132892 DOI: 10.1113/jp276304] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 08/20/2018] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Fragile X syndrome (FXS) is a genetic condition that is the most common form of inherited intellectual impairment and causes a range of neurodevelopmental complications including learning disabilities and intellectual disability and shares many characteristics with autism spectrum disorder (ASD). In the FXS mouse model, Fmr1-/y , impaired synaptic plasticity was restored by pharmacologically inhibiting GluN2A-containing NMDA receptors but not GluN2B-containing receptors. Similar results were obtained by crossing Fmr1-/y with GluN2A knock-out (Grin2A-/- ) mice. These results suggest that dampening the elevated levels of GluN2A-containing NMDA receptors in Fmr1-/y mice has the potential to restore hyperexcitability of the neural circuitry to (a more) normal-like level of brain activity. ABSTRACT NMDA receptors (NMDARs) play important roles in synaptic plasticity at central excitatory synapses, and dysregulation of their function may lead to severe disorders such Fragile X syndrome (FXS). FXS is caused by transcriptional silencing of the FMR1 gene followed by lack of the encoding protein. Here we examined the effects of pharmacological and genetic manipulation of hippocampal NMDAR functions in long-term potentiation (LTP) and depression (LTD). We found impaired NMDAR-dependent LTP in the Fmr1-deficient mice, which could be fully restored when GluN2A-containing NMDARs was pharmacological inhibited. Interestingly, similar LTP effects were observed when the GluN2A gene (Grin2a) was deleted in Fmr1-/y mice (Fmr1-/y /Grin2a-/- double knockout). In addition, GluN2A inhibition improved elevated mGluR5-dependent LTD to normal level in the Fmr1-/y mouse. These findings suggest that GluN2A is a promising target in FXS research that could help us better understand the disorder.
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Affiliation(s)
- Camilla J Lundbye
- Institute of Biomedicine - Physiology, Aarhus University, DK-8000, Aarhus, Denmark
| | - Anna Karina H Toft
- Institute of Biomedicine - Physiology, Aarhus University, DK-8000, Aarhus, Denmark
| | - Tue G Banke
- Institute of Biomedicine - Physiology, Aarhus University, DK-8000, Aarhus, Denmark
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Folsom TD, Higgins L, Markowski TW, Griffin TJ, Fatemi SH. Quantitative proteomics of forebrain subcellular fractions in fragile X mental retardation 1 knockout mice following acute treatment with 2-Methyl-6-(phenylethynyl)pyridine: Relevance to developmental study of schizophrenia. Synapse 2018; 73:e22069. [PMID: 30176067 DOI: 10.1002/syn.22069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/13/2018] [Accepted: 08/30/2018] [Indexed: 12/22/2022]
Abstract
The fragile X mental retardation 1 knockout (Fmr1 KO) mouse replicates behavioral deficits associated with autism, fragile X syndrome, and schizophrenia. Less is known whether protein expression changes are consistent with findings in subjects with schizophrenia. In the current study, we used liquid chromatography tandem mass spectrometry (LC-MS/MS) proteomics to determine the protein expression of four subcellular fractions in the forebrains of Fmr1 KO mice vs. C57BL/6 J mice and the effect of a negative allosteric modulator of mGluR5-2-Methyl-6-(phenylethynyl)pyridine (MPEP)-on protein expression. Strain- and treatment-specific differential expression of proteins was observed, many of which have previously been observed in the brains of subjects with schizophrenia. Western blotting verified the direction and magnitude of change for several proteins in different subcellular fractions as follows: neurofilament light protein (NEFL) and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNP) in the total homogenate; heterogeneous nuclear ribonucleoproteins C1/C2 (HNRNPC) and heterogeneous nuclear ribonucleoprotein D0 (HNRNPD) in the nuclear fraction; excitatory amino acid transporter 2 (EAAT2) and ras-related protein rab 3a (RAB3A) in the synaptic fraction; and ras-related protein rab 35 (RAB35) and neuromodulin (GAP43) in the rough endoplasmic reticulum fraction. Individuals with FXS do not display symptoms of schizophrenia. However, the biomarkers that have been identified suggest that the Fmr1 KO model could potentially be useful in the study of schizophrenia.
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Affiliation(s)
- Timothy D Folsom
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota
| | - LeeAnn Higgins
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Todd W Markowski
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Timothy J Griffin
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota
| | - S Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, Minnesota.,Department of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota
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60
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Westmark PR, Dekundy A, Gravius A, Danysz W, Westmark CJ. Rescue of Fmr1 KO phenotypes with mGluR 5 inhibitors: MRZ-8456 versus AFQ-056. Neurobiol Dis 2018; 119:190-198. [PMID: 30125640 DOI: 10.1016/j.nbd.2018.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/08/2018] [Accepted: 08/13/2018] [Indexed: 12/23/2022] Open
Abstract
Metabotropic glutamate receptor 5 (mGluR5) is a drug target for central nervous system disorders such as fragile X syndrome that involve excessive glutamate-induced excitation. We tested the efficacy of a novel negative allosteric modulator of mGluR5 developed by Merz Pharmaceuticals, MRZ-8456, in comparison to MPEP and AFQ-056 (Novartis, a.k.a. mavoglurant) in both in vivo and in vitro assays in a mouse model of fragile X syndrome, Fmr1KO mice. The in vivo assays included susceptibility to audiogenic-induced seizures and pharmacokinetic measurements of drug availability. The in vitro assays included dose response assessments of biomarker expression and dendritic spine length and density in cultured primary neurons. Both MRZ-8456 and AFQ-056 attenuated wild running and audiogenic-induced seizures in Fmr1KO mice with similar pharmacokinetic profiles. Both drugs significantly reduced dendritic expression of amyloid-beta protein precursor (APP) and rescued the ratio of mature to immature dendritic spines. These findings demonstrate that MRZ-8456, a drug being developed for the treatment of motor complications of L-DOPA in Parkinson's disease and which completed a phase I clinical trial, is effective in attenuating both well-established (seizures and dendritic spine maturity) and exploratory biomarker (APP expression) phenotypes in a mouse model of fragile X syndrome.
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Affiliation(s)
- Pamela R Westmark
- University of Wisconsin-Madison, Department of Neurology, Madison, WI, USA; University of Wisconsin-Madison, Department of Medicine, Madison, WI, USA
| | - Andrzej Dekundy
- Merz Pharmaceuticals GmbH, Eckenheimer Landstrasse 100, 60318 Frankfurt am Main, Germany
| | - Andreas Gravius
- Merz Pharmaceuticals GmbH, Eckenheimer Landstrasse 100, 60318 Frankfurt am Main, Germany
| | - Wojciech Danysz
- Merz Pharmaceuticals GmbH, Eckenheimer Landstrasse 100, 60318 Frankfurt am Main, Germany
| | - Cara J Westmark
- University of Wisconsin-Madison, Department of Neurology, Madison, WI, USA.
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Nguyen RL, Medvedeva YV, Ayyagari TE, Schmunk G, Gargus JJ. Intracellular calcium dysregulation in autism spectrum disorder: An analysis of converging organelle signaling pathways. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1718-1732. [PMID: 30992134 DOI: 10.1016/j.bbamcr.2018.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/18/2018] [Accepted: 08/02/2018] [Indexed: 12/14/2022]
Abstract
Autism spectrum disorder (ASD) is a group of complex, neurological disorders that affect early cognitive, social, and verbal development. Our understanding of ASD has vastly improved with advances in genomic sequencing technology and genetic models that have identified >800 loci with variants that increase susceptibility to ASD. Although these findings have confirmed its high heritability, the underlying mechanisms by which these genes produce the ASD phenotypes have not been defined. Current efforts have begun to "functionalize" many of these variants and envisage how these susceptibility factors converge at key biochemical and biophysical pathways. In this review, we discuss recent work on intracellular calcium signaling in ASD, including our own work, which begins to suggest it as a compelling candidate mechanism in the pathophysiology of autism and a potential therapeutic target. We consider how known variants in the calcium signaling genomic architecture of ASD may exert their deleterious effects along pathways particularly involving organelle dysfunction including the endoplasmic reticulum (ER), a major calcium store, and the mitochondria, a major calcium ion buffer, and theorize how many of these pathways intersect.
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Affiliation(s)
- Rachel L Nguyen
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA; UCI Center for Autism Research and Translation, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Yuliya V Medvedeva
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA; UCI Center for Autism Research and Translation, School of Medicine, University of California, Irvine, Irvine, CA, USA; Department of Neurology, University of California, Irvine, Irvine, CA, USA
| | - Tejasvi E Ayyagari
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA; UCI Center for Autism Research and Translation, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Galina Schmunk
- UCI Center for Autism Research and Translation, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - John Jay Gargus
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, USA; UCI Center for Autism Research and Translation, School of Medicine, University of California, Irvine, Irvine, CA, USA; Department of Pediatrics, Section of Human Genetics and Genomics, University of California, Irvine, Irvine, CA, USA.
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Fu T, Zheng G, Tu G, Yang F, Chen Y, Yao X, Li X, Xue W, Zhu F. Exploring the Binding Mechanism of Metabotropic Glutamate Receptor 5 Negative Allosteric Modulators in Clinical Trials by Molecular Dynamics Simulations. ACS Chem Neurosci 2018. [PMID: 29522307 DOI: 10.1021/acschemneuro.8b00059] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Metabotropic glutamate receptor 5 (mGlu5) plays a key role in synaptic information storage and memory, which is a well-known target for a variety of psychiatric and neurodegenerative disorders. In recent years, the increasing efforts have been focused on the design of allosteric modulators, and the negative allosteric modulators (NAMs) are the front-runners. Recently, the architecture of the transmembrane (TM) domain of mGlu5 receptor has been determined by crystallographic experiment. However, it has been not well understood how the pharmacophores of NAMs accommodated into the allosteric binding site. In this study, molecular dynamics (MD) simulations were performed on mGlu5 receptor bound with NAMs in preclinical or clinical development to shed light on this issue. In order to identify the key residues, the binding free energies as well as per-residue contributions for NAMs binding to mGlu5 receptor were calculated. Subsequently, the in silico site-directed mutagenesis of the key residues was performed to verify the accuracy of simulation models. As a result, the shared common features of the studied 5 clinically important NAMs (mavoglurant, dipraglurant, basimglurant, STX107, and fenobam) interacting with 11 residues in allosteric site were obtained. This comprehensive study presented a better understanding of mGlu5 receptor NAMs binding mechanism, which would be further used as a useful framework to assess and discover novel lead scaffolds for NAMs.
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Affiliation(s)
- Tingting Fu
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
- Innovative Drug Research and Bioinformatics Group, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Guoxun Zheng
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
- Innovative Drug Research and Bioinformatics Group, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Gao Tu
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
- Innovative Drug Research and Bioinformatics Group, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Fengyuan Yang
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
- Innovative Drug Research and Bioinformatics Group, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yuzong Chen
- Bioinformatics and Drug Design Group, Department of Pharmacy, National University of Singapore, Singapore 117543, Singapore
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000, China
| | - Xiaofeng Li
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
- Innovative Drug Research and Bioinformatics Group, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Weiwei Xue
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
| | - Feng Zhu
- Innovative Drug Research and Bioinformatics Group, School of Pharmaceutical Sciences, and Collaborative Innovation Center for Brain Science, Chongqing University, Chongqing 401331, China
- Innovative Drug Research and Bioinformatics Group, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
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63
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Dockendorff TC, Labrador M. The Fragile X Protein and Genome Function. Mol Neurobiol 2018; 56:711-721. [PMID: 29796988 DOI: 10.1007/s12035-018-1122-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/11/2018] [Indexed: 12/21/2022]
Abstract
The fragile X syndrome (FXS) arises from loss of expression or function of the FMR1 gene and is one of the most common monogenic forms of intellectual disability and autism. During the past two decades of FXS research, the fragile X mental retardation protein (FMRP) has been primarily characterized as a cytoplasmic RNA binding protein that facilitates transport of select RNA substrates through neural projections and regulation of translation within synaptic compartments, with the protein products of such mRNAs then modulating cognitive functions. However, the presence of a small fraction of FMRP in the nucleus has long been recognized. Accordingly, recent studies have uncovered several mechanisms or pathways by which FMRP influences nuclear gene expression and genome function. Some of these pathways appear to be independent of the classical role for FMRP as a regulator of translation and point to novel functions, including the possibility that FMRP directly participates in the DNA damage response and in the maintenance of genome stability. In this review, we highlight these advances and discuss how these new findings could contribute to our understanding of FMRP in brain development and function, the neural pathology of fragile X syndrome, and perhaps impact of future therapeutic considerations.
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Affiliation(s)
- Thomas C Dockendorff
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA.
| | - Mariano Labrador
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, 37996, USA.
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64
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Peng J, Wang Y, He F, Chen C, Wu LW, Yang LF, Ma YP, Zhang W, Shi ZQ, Chen C, Xia K, Guo H, Yin F, Pang N. Novel West syndrome candidate genes in a Chinese cohort. CNS Neurosci Ther 2018; 24:1196-1206. [PMID: 29667327 DOI: 10.1111/cns.12860] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/15/2018] [Accepted: 03/18/2018] [Indexed: 12/19/2022] Open
Abstract
AIMS West syndrome (WS) is a classic form of early infantile epileptic encephalopathy (EIEE) characterized by tonic spasms with clustering, arrest of psychomotor development, and hypsarrhythmia on electroencephalography. Genetic defects play a critical role in the pathology of WS, and 54 EIEE genes have been identified till date. This study was designed to uncover new candidate genes for West syndrome. METHODS In this study, we recruited 56 Chinese families with WS of unknown etiology. Whole exome sequencing (WES) was performed to identify Mendelian inheritance rare or novel variants. The association between candidate genes and WS was analyzed from many aspects, including recurrent genes in patients, predicted variant effect on genes, human tolerance to deficient genes, gene expression in the nervous system, coexpression with EIEE genes, mutual interaction with known EIEE proteins, genes related to ion channel or fragile X mental retardation protein function, and mouse models with manifestation of seizures. Genes with supporting evidence from those aspects were defined as highlight candidate genes. RESULTS Whole exome sequencing identified 112 candidate variants in 89 genes. Among the candidate genes, 33 were autosomal dominant, 22 were autosomal recessive, and 34 were X-linked. Complex bioinformatic analysis revealed 17 highlight candidate genes: ATP2A2, CD99L2, CLCN6, CYFIP1, CYFIP2, GNB1, GPT2, HUWE1, KMT2D, MYO18A, NOS3, RYR1, RYR2, RYR3, TAF1, TECTA, and UBA1. The majority of highlight candidate genes are calcium-signaling pathway and mental retardation genes. CONCLUSIONS This is the first WES study of Chinese WS patients with unknown etiology. This combination of phenotypic and genomic data will enable further testing to elucidate mechanisms underlying the pathogenesis of WS.
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Affiliation(s)
- Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ying Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Chen Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Li-Wen Wu
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Li-Fen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Yu-Ping Ma
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Wen Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Zi-Qing Shi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Chao Chen
- Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Kun Xia
- Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Hui Guo
- Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China.,Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Nan Pang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
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65
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Dahlhaus R. Of Men and Mice: Modeling the Fragile X Syndrome. Front Mol Neurosci 2018; 11:41. [PMID: 29599705 PMCID: PMC5862809 DOI: 10.3389/fnmol.2018.00041] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/31/2018] [Indexed: 12/26/2022] Open
Abstract
The Fragile X Syndrome (FXS) is one of the most common forms of inherited intellectual disability in all human societies. Caused by the transcriptional silencing of a single gene, the fragile x mental retardation gene FMR1, FXS is characterized by a variety of symptoms, which range from mental disabilities to autism and epilepsy. More than 20 years ago, a first animal model was described, the Fmr1 knock-out mouse. Several other models have been developed since then, including conditional knock-out mice, knock-out rats, a zebrafish and a drosophila model. Using these model systems, various targets for potential pharmaceutical treatments have been identified and many treatments have been shown to be efficient in preclinical studies. However, all attempts to turn these findings into a therapy for patients have failed thus far. In this review, I will discuss underlying difficulties and address potential alternatives for our future research.
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Affiliation(s)
- Regina Dahlhaus
- Institute for Biochemistry, Emil-Fischer Centre, University of Erlangen-Nürnberg, Erlangen, Germany
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66
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McGraw CM, Ward CS, Samaco RC. Genetic rodent models of brain disorders: Perspectives on experimental approaches and therapeutic strategies. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2018; 175:368-379. [PMID: 28910526 PMCID: PMC5659732 DOI: 10.1002/ajmg.c.31570] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 06/28/2017] [Indexed: 12/14/2022]
Abstract
Neurobehavioral disorders comprised of neurodegenerative, neurodevelopmental, and psychiatric disorders together represent leading causes of morbidity and mortality. Despite significant academic research and industry efforts to elucidate the disease mechanisms operative in these disorders and to develop mechanism‐based therapies, our understanding remains incomplete and our access to tractable therapeutic interventions severely limited. The magnitude of these short‐comings can be measured by the growing list of disappointing clinical trials based on initially promising compounds identified in genetic animal models. This review and commentary will explore why this may be so, focusing on the central role that genetic models of neurobehavioral disorders have come to occupy in current efforts to identify disease mechanisms and therapies. In particular, we will highlight the unique pitfalls and challenges that have hampered success in these models as compared to genetic models of non‐neurological diseases as well as to symptom‐based models of the early 20th century that led to the discovery of all major classes of psychoactive pharmaceutical compounds still used today. Using examples from specific genetic rodent models of human neurobehavioral disorders, we will highlight issues of reproducibility, construct validity, and translational relevance in the hopes that these examples will be instructive toward greater success in future endeavors. Lastly, we will champion a two‐pronged approach toward identifying novel therapies for neurobehavioral disorders that makes greater use of the historically more successful symptom‐based approaches in addition to more mechanism‐based approaches.
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Affiliation(s)
- Christopher M McGraw
- Department of Neurology, University of California, San Francisco, San Francisco, California
| | - Christopher S Ward
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Rodney C Samaco
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas
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67
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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: 217] [Impact Index Per Article: 31.0] [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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68
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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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69
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Stoppel LJ, Auerbach BD, Senter RK, Preza AR, Lefkowitz RJ, Bear MF. β-Arrestin2 Couples Metabotropic Glutamate Receptor 5 to Neuronal Protein Synthesis and Is a Potential Target to Treat Fragile X. Cell Rep 2017; 18:2807-2814. [PMID: 28329674 DOI: 10.1016/j.celrep.2017.02.075] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/31/2017] [Accepted: 02/24/2017] [Indexed: 10/19/2022] Open
Abstract
Synaptic protein synthesis is essential for modification of the brain by experience and is aberrant in several genetically defined disorders, notably fragile X (FX), a heritable cause of autism and intellectual disability. Neural activity directs local protein synthesis via activation of metabotropic glutamate receptor 5 (mGlu5), yet how mGlu5 couples to the intracellular signaling pathways that regulate mRNA translation is poorly understood. Here, we provide evidence that β-arrestin2 mediates mGlu5-stimulated protein synthesis in the hippocampus and show that genetic reduction of β-arrestin2 corrects aberrant synaptic plasticity and cognition in the Fmr1-/y mouse model of FX. Importantly, reducing β-arrestin2 does not induce psychotomimetic activity associated with full mGlu5 inhibitors and does not affect Gq signaling. Thus, in addition to identifying a key requirement for mGlu5-stimulated protein synthesis, these data suggest that β-arrestin2-biased negative modulators of mGlu5 offer significant advantages over first-generation inhibitors for the treatment of FX and related disorders.
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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 02139, USA
| | - Benjamin D Auerbach
- The Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Rebecca K Senter
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anthony R Preza
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert J Lefkowitz
- Departments of Medicine and Biochemistry, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Mark F Bear
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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70
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Gurney ME, Cogram P, Deacon RM, Rex C, Tranfaglia M. Multiple Behavior Phenotypes of the Fragile-X Syndrome Mouse Model Respond to Chronic Inhibition of Phosphodiesterase-4D (PDE4D). Sci Rep 2017; 7:14653. [PMID: 29116166 PMCID: PMC5677090 DOI: 10.1038/s41598-017-15028-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/18/2017] [Indexed: 01/14/2023] Open
Abstract
Fragile-X syndrome (FXS) patients display intellectual disability and autism spectrum disorder due to silencing of the X-linked, fragile-X mental retardation-1 (FMR1) gene. Dysregulation of cAMP metabolism is a consistent finding in patients and in the mouse and fly FXS models. We therefore explored if BPN14770, a prototypic phosphodiesterase-4D negative allosteric modulator (PDE4D-NAM) in early human clinical trials, might provide therapeutic benefit in the mouse FXS model. Daily treatment of adult male fmr1 C57Bl6 knock-out mice with BPN14770 for 14 days reduced hyperarousal, improved social interaction, and improved natural behaviors such as nesting and marble burying as well as dendritic spine morphology. There was no decrement in behavioral scores in control C57Bl6 treated with BPN14770. The behavioral benefit of BPN14770 persisted two weeks after washout of the drug. Thus, BPN14770 may be useful for the treatment of fragile-X syndrome and other disorders with decreased cAMP signaling.
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Affiliation(s)
- Mark E Gurney
- Tetra Discovery Partners, Inc, Grand Rapids, MI, USA.
| | - Patricia Cogram
- FRAXA-DVI, FRAXA, Santiago, Chile.,Laboratory of Molecular Neuropsychiatry, Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, National Scientific and Technical Research Council, Buenos Aires, Argentina.,IEB, Faculty of Science, University of Chile, Santiago, Chile
| | - Robert M Deacon
- FRAXA-DVI, FRAXA, Santiago, Chile.,Laboratory of Molecular Neuropsychiatry, Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, National Scientific and Technical Research Council, Buenos Aires, Argentina.,IEB, Faculty of Science, University of Chile, Santiago, Chile
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71
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Chatterjee M, Kurup PK, Lundbye CJ, Hugger Toft AK, Kwon J, Benedict J, Kamceva M, Banke TG, Lombroso PJ. STEP inhibition reverses behavioral, electrophysiologic, and synaptic abnormalities in Fmr1 KO mice. Neuropharmacology 2017; 128:43-53. [PMID: 28943283 DOI: 10.1016/j.neuropharm.2017.09.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/26/2017] [Accepted: 09/19/2017] [Indexed: 12/11/2022]
Abstract
Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability, with additional symptoms including attention deficit and hyperactivity, anxiety, impulsivity, and repetitive movements or actions. The majority of FXS cases are attributed to a CGG expansion that leads to transcriptional silencing and diminished expression of fragile X mental retardation protein (FMRP). FMRP, an RNA binding protein, regulates the synthesis of dendritically-translated mRNAs by stalling ribosomal translation. Loss of FMRP leads to increased translation of some of these mRNAs, including the CNS-specific tyrosine phosphatase STEP (STriatal-Enriched protein tyrosine Phosphatase). Genetic reduction of STEP in Fmr1 KO mice have diminished audiogenic seizures and a reversal of social and non-social anxiety-related abnormalities. This study investigates whether a newly discovered STEP inhibitor (TC-2153) could attenuate the behavioral and synaptic abnormalities in Fmr1 KO mice. TC-2153 reversed audiogenic seizure incidences, reduced hyperactivity, normalized anxiety states, and increased sociability in Fmr1 KO mice. Moreover, TC-2153 reduced dendritic spine density and improved synaptic aberrations in Fmr1 KO neuronal cultures as well as in vivo. TC-2153 also reversed the mGluR-mediated exaggerated LTD in brain slices derived from Fmr1 KO mice. These studies suggest that STEP inhibition may have therapeutic benefit in FXS.
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Affiliation(s)
- Manavi Chatterjee
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States.
| | - Pradeep K Kurup
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States
| | - Camilla J Lundbye
- Institute of Biomedicine - Physiology, Aarhus University, Aarhus, 8000, Denmark
| | | | - Jeemin Kwon
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States
| | - Jessie Benedict
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States
| | - Marija Kamceva
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States
| | - Tue G Banke
- Institute of Biomedicine - Physiology, Aarhus University, Aarhus, 8000, Denmark
| | - Paul J Lombroso
- Child Study Center, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States; Department of Psychiatry, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States; Department of Neuroscience, Yale University, 230 South Frontage Rd, New Haven, CT, 06520, United States.
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72
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Thomson SR, Seo SS, Barnes SA, Louros SR, Muscas M, Dando O, Kirby C, Wyllie DJA, Hardingham GE, Kind PC, Osterweil EK. Cell-Type-Specific Translation Profiling Reveals a Novel Strategy for Treating Fragile X Syndrome. Neuron 2017; 95:550-563.e5. [PMID: 28772121 PMCID: PMC5548955 DOI: 10.1016/j.neuron.2017.07.013] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 04/22/2017] [Accepted: 07/12/2017] [Indexed: 11/08/2022]
Abstract
Excessive mRNA translation downstream of group I metabotropic glutamate receptors (mGlu1/5) is a core pathophysiology of fragile X syndrome (FX); however, the differentially translating mRNAs that contribute to altered neural function are not known. We used translating ribosome affinity purification (TRAP) and RNA-seq to identify mistranslating mRNAs in CA1 pyramidal neurons of the FX mouse model (Fmr1−/y) hippocampus, which exhibit exaggerated mGlu1/5-induced long-term synaptic depression (LTD). In these neurons, we find that the Chrm4 transcript encoding muscarinic acetylcholine receptor 4 (M4) is excessively translated, and synthesis of M4 downstream of mGlu5 activation is mimicked and occluded. Surprisingly, enhancement rather than inhibition of M4 activity normalizes core phenotypes in the Fmr1−/y, including excessive protein synthesis, exaggerated mGluR-LTD, and audiogenic seizures. These results suggest that not all excessively translated mRNAs in the Fmr1−/y brain are detrimental, and some may be candidates for enhancement to correct pathological changes in the FX brain. TRAP-seq reveals altered translation of >120 mRNAs in Fmr1−/y CA1 pyramidal neurons Muscarinic receptor M4 is excessively translated in Fmr1−/y hippocampus Enhancement, not inhibition, of M4 corrects core phenotypes in the Fmr1−/y mouse Not all excessively translating mRNAs are detrimental to Fmr1−/y brain function
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Affiliation(s)
- Sophie R Thomson
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Sang S Seo
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Stephanie A Barnes
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Susana R Louros
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Melania Muscas
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Owen Dando
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Caoimhe Kirby
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - David J A Wyllie
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Giles E Hardingham
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; UK Dementia Research Institute, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Peter C Kind
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Emily K Osterweil
- Centre for Integrative Physiology/Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
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73
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Harkins CM, Dominick KC, Wink LK, Pedapati EV, Shaffer RC, Fitzpatrick SE, Davenport MH, Sweeney JA, Erickson CA. Challenges in Conducting Clinical Trials for Pharmacotherapies in Fragile X Syndrome: Lessons Learned. Pharmaceut Med 2017. [DOI: 10.1007/s40290-017-0199-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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74
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Cheng GR, Li XY, Xiang YD, Liu D, McClintock SM, Zeng Y. The implication of AMPA receptor in synaptic plasticity impairment and intellectual disability in fragile X syndrome. Physiol Res 2017; 66:715-727. [PMID: 28730825 DOI: 10.33549/physiolres.933473] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fragile X syndrome (FXS) is the most frequently inherited form of intellectual disability and prevalent single-gene cause of autism. A priority of FXS research is to determine the molecular mechanisms underlying the cognitive and social functioning impairments in humans and the FXS mouse model. Glutamate ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPARs) mediate a majority of fast excitatory neurotransmission in the central nervous system and are critically important for nearly all aspects of brain function, including neuronal development, synaptic plasticity, and learning and memory. Both preclinical and clinical studies have indicated that expression, trafficking, and functions of AMPARs are altered and result in altered synapse development and plasticity, cognitive impairment, and poor mental health in FXS. In this review, we discuss the contribution of AMPARs to disorders of FXS by highlighting recent research advances with a specific focus on change in AMPARs expression, trafficking, and dependent synaptic plasticity. Since changes in synaptic strength underlie the basis of learning, development, and disease, we suggest that the current knowledge base of AMPARs has reached a unique point to permit a comprehensive re-evaluation of their roles in FXS.
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Affiliation(s)
- Gui-Rong Cheng
- Brain and Cognition Research Institute, School of Medicine, Wuhan University of Science and Technology, Wuhan, China, Hubei Key Laboratory of Hazard Identification and Control for Occupational Disease, Wuhan, China.
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75
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Enhanced Excitatory Connectivity and Disturbed Sound Processing in the Auditory Brainstem of Fragile X Mice. J Neurosci 2017; 37:7403-7419. [PMID: 28674175 DOI: 10.1523/jneurosci.2310-16.2017] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 06/06/2017] [Accepted: 06/15/2017] [Indexed: 12/11/2022] Open
Abstract
Hypersensitivity to sounds is one of the prevalent symptoms in individuals with Fragile X syndrome (FXS). It manifests behaviorally early during development and is often used as a landmark for treatment efficacy. However, the physiological mechanisms and circuit-level alterations underlying this aberrant behavior remain poorly understood. Using the mouse model of FXS (Fmr1 KO), we demonstrate that functional maturation of auditory brainstem synapses is impaired in FXS. Fmr1 KO mice showed a greatly enhanced excitatory synaptic input strength in neurons of the lateral superior olive (LSO), a prominent auditory brainstem nucleus, which integrates ipsilateral excitation and contralateral inhibition to compute interaural level differences. Conversely, the glycinergic, inhibitory input properties remained unaffected. The enhanced excitation was the result of an increased number of cochlear nucleus fibers converging onto one LSO neuron, without changing individual synapse properties. Concomitantly, immunolabeling of excitatory ending markers revealed an increase in the immunolabeled area, supporting abnormally elevated excitatory input numbers. Intrinsic firing properties were only slightly enhanced. In line with the disturbed development of LSO circuitry, auditory processing was also affected in adult Fmr1 KO mice as shown with single-unit recordings of LSO neurons. These processing deficits manifested as an increase in firing rate, a broadening of the frequency response area, and a shift in the interaural level difference function of LSO neurons. Our results suggest that this aberrant synaptic development of auditory brainstem circuits might be a major underlying cause of the auditory processing deficits in FXS.SIGNIFICANCE STATEMENT Fragile X Syndrome (FXS) is the most common inheritable form of intellectual impairment, including autism. A core symptom of FXS is extreme sensitivity to loud sounds. This is one reason why individuals with FXS tend to avoid social interactions, contributing to their isolation. Here, a mouse model of FXS was used to investigate the auditory brainstem where basic sound information is first processed. Loss of the Fragile X mental retardation protein leads to excessive excitatory compared with inhibitory inputs in neurons extracting information about sound levels. Functionally, this elevated excitation results in increased firing rates, and abnormal coding of frequency and binaural sound localization cues. Imbalanced early-stage sound level processing could partially explain the auditory processing deficits in FXS.
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76
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Pellerin D, Lortie A, Corbin F. Platelets as a surrogate disease model of neurodevelopmental disorders: Insights from Fragile X Syndrome. Platelets 2017; 29:113-124. [PMID: 28660769 DOI: 10.1080/09537104.2017.1317733] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fragile X Syndrome (FXS) is the most common inherited form of intellectual disability and the leading monogenic cause of autism spectrum disorders (ASD). Despite a large number of therapeutics developed in past years, there is currently no targeted treatment approved for FXS. In fact, translation of the positive and very promising preclinical findings from animal models to human subjects has so far fallen short owing in part to the low predictive validity of the Fmr1 ko mouse, an overly simplistic model of the complex human disease. This issue stresses the critical need to identify new surrogate human peripheral cell models of FXS, which may in fact allow for the identification of novel and more efficient therapies. Of all described models, blood platelets appear to be one of the most promising and appropriate disease models of FXS, in part owing to their close biochemical similarities with neurons. Noteworthy, they also recapitulate some of FXS neuron's core molecular dysregulations, such as hyperactivity of the MAPK/ERK and PI3K/Akt/mTOR pathways, elevated enzymatic activity of MMP9 and decreased production of cAMP. Platelets might therefore help furthering our understanding of FXS pathophysiology and might also lead to the identification of disease-specific biomarkers, as was shown in several psychiatric disorders such as schizophrenia and Alzheimer's disease. Moreover, there is additional evidence suggesting that platelet signaling may assist with prediction of cognitive phenotype and could represent a potent readout of drug efficacy in clinical trials. Globally, given the neurobiological overlap between different forms of intellectual disability, platelets may be a valuable window to access the molecular underpinnings of ASD and other neurodevelopmental disorders (NDD) sharing similar synaptic plasticity defects with FXS. Platelets are indeed an attractive model for unraveling pathophysiological mechanisms involved in NDD as well as to search for diagnostic and therapeutic biomarkers.
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Affiliation(s)
- David Pellerin
- a Department of Biochemistry, Faculty of Medicine and Health Sciences , Université de Sherbrooke , Sherbrooke , QC , Canada.,b Department of Neurology and Neurosurgery, Faculty of Medicine , McGill University , Montreal , QC , Canada
| | - Audrey Lortie
- a Department of Biochemistry, Faculty of Medicine and Health Sciences , Université de Sherbrooke , Sherbrooke , QC , Canada
| | - François Corbin
- a Department of Biochemistry, Faculty of Medicine and Health Sciences , Université de Sherbrooke , Sherbrooke , QC , Canada
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77
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Erickson CA, Davenport MH, Schaefer TL, Wink LK, Pedapati EV, Sweeney JA, Fitzpatrick SE, Brown WT, Budimirovic D, Hagerman RJ, Hessl D, Kaufmann WE, Berry-Kravis E. Fragile X targeted pharmacotherapy: lessons learned and future directions. J Neurodev Disord 2017; 9:7. [PMID: 28616096 PMCID: PMC5467059 DOI: 10.1186/s11689-017-9186-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/18/2017] [Indexed: 01/04/2023] Open
Abstract
Our understanding of fragile X syndrome (FXS) pathophysiology continues to improve and numerous potential drug targets have been identified. Yet, current prescribing practices are only symptom-based in order to manage difficult behaviors, as no drug to date is approved for the treatment of FXS. Drugs impacting a diversity of targets in the brain have been studied in recent FXS-specific clinical trials. While many drugs have focused on regulation of enhanced glutamatergic or deficient GABAergic neurotransmission, compounds studied have not been limited to these mechanisms. As a single-gene disorder, it was thought that FXS would have consistent drug targets that could be modulated with pharmacotherapy and lead to significant improvement. Unfortunately, despite promising results in FXS animal models, translational drug treatment development in FXS has largely failed. Future success in this field will depend on learning from past challenges to improve clinical trial design, choose appropriate outcome measures and age range choices, and find readily modulated drug targets. Even with many negative placebo-controlled study results, the field continues to move forward exploring both the new mechanistic drug approaches combined with ways to improve trial execution. This review summarizes the known phenotype and pathophysiology of FXS and past clinical trial rationale and results, and discusses current challenges facing the field and lessons from which to learn for future treatment development efforts.
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Affiliation(s)
- Craig A Erickson
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Department of Psychiatry, College of Medicine, University of Cincinnati, Cincinnati, OH USA
| | - Matthew H Davenport
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Department of Biomedical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH USA
| | - Tori L Schaefer
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - Logan K Wink
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Department of Psychiatry, College of Medicine, University of Cincinnati, Cincinnati, OH USA
| | - Ernest V Pedapati
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Department of Psychiatry, College of Medicine, University of Cincinnati, Cincinnati, OH USA
| | - John A Sweeney
- Department of Psychiatry, College of Medicine, University of Cincinnati, Cincinnati, OH USA
| | - Sarah E Fitzpatrick
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - W Ted Brown
- Institute for Basic Research in Developmental Disabilities, New York, NY USA
| | - Dejan Budimirovic
- Clinical Research Center, Clinical Trials Unit, Fragile X Clinic, Kennedy Krieger Institute, The Johns Hopkins Medical Institutions, Baltimore, MD USA.,Departments of Psychiatry & Behavioral Sciences, Child Psychiatry, The Johns Hopkins Medical Institutions, Baltimore, MD USA
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Davis Medical Center, University of California, Sacramento, CA USA.,Department of Pediatrics, Davis Medical Center, University of California, Sacramento, California USA
| | - David Hessl
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, Davis Medical Center, University of California, Sacramento, CA USA.,Department of Psychiatry and Behavioral Sciences, Davis Medical Center, University of California, Sacramento, California USA
| | - Walter E Kaufmann
- Greenwood Genetic Center, Greenwood, SC USA.,Boston Children's Hospital, Boston, Massachusetts USA
| | - Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, Biochemistry, Rush University Medical Center, Chicago, Illinois USA
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78
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Schaefer TL, Davenport MH, Grainger LM, Robinson CK, Earnheart AT, Stegman MS, Lang AL, Ashworth AA, Molinaro G, Huber KM, Erickson CA. Acamprosate in a mouse model of fragile X syndrome: modulation of spontaneous cortical activity, ERK1/2 activation, locomotor behavior, and anxiety. J Neurodev Disord 2017; 9:6. [PMID: 28616095 PMCID: PMC5467053 DOI: 10.1186/s11689-017-9184-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 01/13/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Fragile X Syndrome (FXS) occurs as a result of a silenced fragile X mental retardation 1 gene (FMR1) and subsequent loss of fragile X mental retardation protein (FMRP) expression. Loss of FMRP alters excitatory/inhibitory signaling balance, leading to increased neuronal hyperexcitability and altered behavior. Acamprosate (the calcium salt of N-acetylhomotaurinate), a drug FDA-approved for relapse prevention in the treatment of alcohol dependence in adults, is a novel agent with multiple mechanisms that may be beneficial for people with FXS. There are questions regarding the neuroactive effects of acamprosate and the significance of the molecule's calcium moiety. Therefore, the electrophysiological, cellular, molecular, and behavioral effects of acamprosate were assessed in the Fmr1-/y (knock out; KO) mouse model of FXS controlling for the calcium salt in several experiments. METHODS Fmr1 KO mice and their wild-type (WT) littermates were utilized to assess acamprosate treatment on cortical UP state parameters, dendritic spine density, and seizure susceptibility. Brain extracellular-signal regulated kinase 1/2 (ERK1/2) activation was used to investigate this signaling molecule as a potential biomarker for treatment response. Additional adult mice were used to assess chronic acamprosate treatment and any potential effects of the calcium moiety using CaCl2 treatment on behavior and nuclear ERK1/2 activation. RESULTS Acamprosate attenuated prolonged cortical UP state duration, decreased elevated ERK1/2 activation in brain tissue, and reduced nuclear ERK1/2 activation in the dentate gyrus in KO mice. Acamprosate treatment modified behavior in anxiety and locomotor tests in Fmr1 KO mice in which control-treated KO mice were shown to deviate from control-treated WT mice. Mice treated with CaCl2 were not different from saline-treated mice in the adult behavior battery or nuclear ERK1/2 activation. CONCLUSIONS These data indicate that acamprosate, and not calcium, improves function reminiscent of reduced anxiety-like behavior and hyperactivity in Fmr1 KO mice and that acamprosate attenuates select electrophysiological and molecular dysregulation that may play a role in the pathophysiology of FXS. Differences between control-treated KO and WT mice were not evident in a recognition memory test or in examination of acoustic startle response/prepulse inhibition which impeded conclusions from being made about the treatment effects of acamprosate in these instances.
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Affiliation(s)
- Tori L Schaefer
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - Matthew H Davenport
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - Lindsay M Grainger
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - Chandler K Robinson
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - Anthony T Earnheart
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
| | - Melinda S Stegman
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Present address: Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229 USA
| | - Anna L Lang
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Present address: Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202 USA
| | - Amy A Ashworth
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA.,Present address: BlackbookHR, Cincinnati, OH 45202 USA
| | - Gemma Molinaro
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
| | - Kimberly M Huber
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
| | - Craig A Erickson
- Division of Psychiatry, MLC 7004, Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH 45229-3039 USA
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79
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Abstract
OBJECTIVES The purpose of this systematic literature review is to describe what is known about fragile X syndrome (FXS) and to identify research gaps. The results can be used to help inform future public health research and provide pediatricians with up-to-date information about the implications of the condition for individuals and their families. METHODS An electronic literature search was conducted, guided by a variety of key words. The search focused on 4 areas of both clinical and public health importance: (1) the full mutation phenotype, (2) developmental trajectories across the life span, (3) available interventions and treatments, and (4) impact on the family. A total of 661 articles were examined and 203 were included in the review. RESULTS The information is presented in the following categories: developmental profile (cognition, language, functional skills, and transition to adulthood), social-emotional profile (cooccurring psychiatric conditions and behavior problems), medical profile (physical features, seizures, sleep, health problems, and physiologic features), treatment and interventions (educational/behavioral, allied health services, and pharmacologic), and impact on the family (family environment and financial impact). Research gaps also are presented. CONCLUSIONS The identification and treatment of FXS remains an important public health and clinical concern. The information presented in this article provides a more robust understanding of FXS and the impact of this complex condition for pediatricians. Despite a wealth of information about the condition, much work remains to fully support affected individuals and their families.
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Affiliation(s)
- Melissa Raspa
- RTI International, Research Triangle Park, North Carolina; and
| | - Anne C Wheeler
- RTI International, Research Triangle Park, North Carolina; and
| | - Catharine Riley
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
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80
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Lee E, Lee J, Kim E. Excitation/Inhibition Imbalance in Animal Models of Autism Spectrum Disorders. Biol Psychiatry 2017; 81:838-847. [PMID: 27450033 DOI: 10.1016/j.biopsych.2016.05.011] [Citation(s) in RCA: 294] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/02/2016] [Accepted: 05/16/2016] [Indexed: 12/19/2022]
Abstract
Imbalances between excitation and inhibition in synaptic transmission and neural circuits have been implicated in autism spectrum disorders. Excitation and inhibition imbalances are frequently observed in animal models of autism spectrum disorders, and their correction normalizes key autistic-like phenotypes in these animals. These results suggest that excitation and inhibition imbalances may contribute to the development and maintenance of autism spectrum disorders and represent an important therapeutic target.
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Affiliation(s)
- Eunee Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea
| | - Jiseok Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
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81
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Kazim SF, Chuang SC, Zhao W, Wong RKS, Bianchi R, Iqbal K. Early-Onset Network Hyperexcitability in Presymptomatic Alzheimer's Disease Transgenic Mice Is Suppressed by Passive Immunization with Anti-Human APP/Aβ Antibody and by mGluR5 Blockade. Front Aging Neurosci 2017; 9:71. [PMID: 28392767 PMCID: PMC5364175 DOI: 10.3389/fnagi.2017.00071] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 03/08/2017] [Indexed: 11/26/2022] Open
Abstract
Cortical and hippocampal network hyperexcitability appears to be an early event in Alzheimer’s disease (AD) pathogenesis, and may contribute to memory impairment. It remains unclear if network hyperexcitability precedes memory impairment in mouse models of AD and what are the underlying cellular mechanisms. We thus evaluated seizure susceptibility and hippocampal network hyperexcitability at ~3 weeks of age [prior to amyloid beta (Aβ) plaque deposition, neurofibrillary pathology, and cognitive impairment] in a triple transgenic mouse model of familial AD (3xTg-AD mouse) that harbors mutated human Aβ precursor protein (APP), tau and presenilin 1 (PS1) genes. Audiogenic seizures were elicited in a higher proportion of 3xTg-AD mice compared with wild type (WT) controls. Seizure susceptibility in 3xTg-AD mice was attenuated either by passive immunization with anti-human APP/Aβ antibody (6E10) or by blockade of metabotropic glutamate receptor 5 (mGluR5) with the selective antagonist, 2-methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP). In in vitro hippocampal slices, suppression of synaptic inhibition with the GABAA receptor antagonist, bicuculline, induced prolonged epileptiform (>1.5 s in duration) ictal-like discharges in the CA3 neuronal network in the majority of the slices from 3xTg-AD mice. In contrast, only short epileptiform (<1.5 s in duration) interictal-like discharges were observed following bicuculline application in the CA3 region of WT slices. The ictal-like activity in CA3 region of the hippocampus was significantly reduced in the 6E10-immunized compared to the saline-treated 3xTg-AD mice. MPEP acutely suppressed the ictal-like discharges in 3xTg-AD slices. Remarkably, epileptiform discharge duration positively correlated with intraneuronal human (transgenic) APP/Aβ expression in the CA3 region of the hippocampus. Our data suggest that in a mouse model of familial AD, hypersynchronous network activity underlying seizure susceptibility precedes Aβ plaque pathology and memory impairment. This early-onset network hyperexcitability can be suppressed by passive immunization with an anti-human APP/Aβ antibody and by mGluR5 blockade in 3xTg-AD mice.
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Affiliation(s)
- Syed F Kazim
- Robert F. Furchgott Center for Neural and Behavioral Science and Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Medical CenterBrooklyn, NY, USA; Department of Neurochemistry and SUNY Downstate/NYSIBR Center for Developmental Neuroscience, New York State Institute for Basic Research (NYSIBR)Staten Island, NY, USA; Graduate Program in Neural and Behavioral Science, SUNY Downstate Medical CenterBrooklyn, NY, USA
| | - Shih-Chieh Chuang
- Robert F. Furchgott Center for Neural and Behavioral Science and Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Medical Center Brooklyn, NY, USA
| | - Wangfa Zhao
- Robert F. Furchgott Center for Neural and Behavioral Science and Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Medical Center Brooklyn, NY, USA
| | - Robert K S Wong
- Robert F. Furchgott Center for Neural and Behavioral Science and Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Medical Center Brooklyn, NY, USA
| | - Riccardo Bianchi
- Robert F. Furchgott Center for Neural and Behavioral Science and Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Medical Center Brooklyn, NY, USA
| | - Khalid Iqbal
- Department of Neurochemistry and SUNY Downstate/NYSIBR Center for Developmental Neuroscience, New York State Institute for Basic Research (NYSIBR) Staten Island, NY, USA
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82
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Sethna F, Feng W, Ding Q, Robison AJ, Feng Y, Wang H. Enhanced expression of ADCY1 underlies aberrant neuronal signalling and behaviour in a syndromic autism model. Nat Commun 2017; 8:14359. [PMID: 28218269 PMCID: PMC5321753 DOI: 10.1038/ncomms14359] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 12/20/2016] [Indexed: 12/14/2022] Open
Abstract
Fragile X syndrome (FXS), caused by the loss of functional FMRP, is a leading cause of autism. Neurons lacking FMRP show aberrant mRNA translation and intracellular signalling. Here, we identify that, in Fmr1 knockout neurons, type 1 adenylyl cyclase (Adcy1) mRNA translation is enhanced, leading to excessive production of ADCY1 protein and insensitivity to neuronal stimulation. Genetic reduction of Adcy1 normalizes the aberrant ERK1/2- and PI3K-mediated signalling, attenuates excessive protein synthesis and corrects dendritic spine abnormality in Fmr1 knockout mice. Genetic reduction of Adcy1 also ameliorates autism-related symptoms including repetitive behaviour, defective social interaction and audiogenic seizures. Moreover, peripheral administration of NB001, an experimental compound that preferentially suppresses ADCY1 activity over other ADCY subtypes, attenuates the behavioural abnormalities in Fmr1 knockout mice. These results demonstrate a connection between the elevated Adcy1 translation and abnormal ERK1/2 signalling and behavioural symptoms in FXS. Fragile X syndrome (FXS) is a leading cause of autism and neurons lacking FMRP show aberrant mRNA translation and intracellular signalling. Here, the authors show that neurons from Fmr1 knockout mice have increased levels of ADCY1 protein, producing abnormal ERK1/2 signalling, dysregulated protein synthesis and behavioural symptoms associated with FXS.
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Affiliation(s)
- Ferzin Sethna
- Genetics Program, Michigan State University, East Lansing, Michigan 48824, USA
| | - Wei Feng
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Qi Ding
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Alfred J Robison
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824, USA.,Neuroscience Program, Michigan State University, East Lansing, Michigan 48824, USA
| | - Yue Feng
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Hongbing Wang
- Department of Physiology, Michigan State University, East Lansing, Michigan 48824, USA.,Neuroscience Program, Michigan State University, East Lansing, Michigan 48824, USA
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83
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Emmitte KA. mGlu5negative allosteric modulators: a patent review (2013 - 2016). Expert Opin Ther Pat 2017; 27:691-706. [DOI: 10.1080/13543776.2017.1280466] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
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84
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Genetic and Pharmacological Reversibility of Phenotypes in Mouse Models of Autism Spectrum Disorder. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2017; 224:189-211. [PMID: 28551757 DOI: 10.1007/978-3-319-52498-6_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
As autism spectrum disorder (ASD) is largely regarded as a neurodevelopmental condition, long-time consensus was that its hallmark features are irreversible. However, several studies from recent years using defined mouse models of ASD have provided clear evidence that in mice neurobiological and behavioural alterations can be ameliorated or even reversed by genetic restoration or pharmacological treatment either before or after symptom onset. Here, we review findings on genetic and pharmacological reversibility of phenotypes in mouse models of ASD. Our review should give a comprehensive overview on both aspects and encourage future studies to better understand the underlying molecular mechanisms that might be translatable from animals to humans.
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85
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Albasanz JL, Santana S, Guzman-Sanchez F, León D, Burgos JS, Martín M. 2-Methyl-6-(phenylethynyl)pyridine Hydrochloride Modulates Metabotropic Glutamate 5 Receptors Endogenously Expressed in Zebrafish Brain. ACS Chem Neurosci 2016; 7:1690-1697. [PMID: 27635438 DOI: 10.1021/acschemneuro.6b00213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Due to phylogenetic proximity to the human, zebrafish has been recognized as a reliable model to study Alzheimer's disease (AD) and other central nervous system disorders. Furthermore, metabotropic glutamate receptors have been previously reported to be impaired in brain from AD patients. Metabotropic glutamate 5 (mGlu5) receptors are G-protein coupled receptors proposed as potential targets for therapy of different neurodegenerative disorders. Thus, MPEP (2-methyl-6-(phenylethynyl)pyridine hydrochloride), a selective noncompetitive mGlu5 receptor antagonist, has been suggested for pharmacological treatment of AD. The aim of the present work was to quantify mGlu5 receptors in brain from zebrafish and to study the possible modulation of these receptors by MPEP treatment. To this end, radioligand binding assay and open field test were used. Results showed a slightly higher presence of mGlu5 receptors in brain from male than in that from female zebrafish. However, a significant increase of mGlu5 receptor in male without variation in female was observed after MPEP treatment. This gender specific response was also observed in locomotor behavior, being significantly decreased only in male zebrafish. These results confirm the presence of mGlu5 receptors in brain from zebrafish and their gender specific modulation by selective antagonist treatment and suggest a role of these receptors on locomotor activity, which is affected in many disorders. In addition, our data point to zebrafish as a useful model to study mGlu receptor function in both healthy and pathological conditions.
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Affiliation(s)
- José Luis Albasanz
- Departamento de Química Inorgánica,
Orgánica y Bioquímica, Facultad de Medicina de Ciudad
Real/Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Centro Regional de Investigaciones Biomédicas (CRIB), Avenida Camilo José Cela 10, 13071 Ciudad Real, Spain
| | | | | | - David León
- Departamento de Química Inorgánica,
Orgánica y Bioquímica, Facultad de Medicina de Ciudad
Real/Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Centro Regional de Investigaciones Biomédicas (CRIB), Avenida Camilo José Cela 10, 13071 Ciudad Real, Spain
| | | | - Mairena Martín
- Departamento de Química Inorgánica,
Orgánica y Bioquímica, Facultad de Medicina de Ciudad
Real/Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Centro Regional de Investigaciones Biomédicas (CRIB), Avenida Camilo José Cela 10, 13071 Ciudad Real, Spain
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86
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Study of the Genetic Etiology of Primary Ovarian Insufficiency: FMR1 Gene. Genes (Basel) 2016; 7:genes7120123. [PMID: 27983607 PMCID: PMC5192499 DOI: 10.3390/genes7120123] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 01/28/2023] Open
Abstract
Menopause is a period of women’s life characterized by the cessation of menses in a definitive way. The mean age for menopause is approximately 51 years. Primary ovarian insufficiency (POI) refers to ovarian dysfunction defined as irregular menses and elevated gonadotrophin levels before or at the age of 40 years. The etiology of POI is unknown but several genes have been reported as being of significance. The fragile X mental retardation 1 gene (FMR1) is one of the most important genes associated with POI. The FMR1 gene contains a highly polymorphic CGG repeat in the 5′ untranslated region of exon 1. Four allelic forms have been defined with respect to CGG repeat length and instability during transmission. Normal (5–44 CGG) alleles are usually transmitted from parent to offspring in a stable manner. The full mutation form consists of over 200 repeats, which induces hypermethylation of the FMR1 gene promoter and the subsequent silencing of the gene, associated with Fragile X Syndrome (FXS). Finally, FMR1 intermediate (45–54 CGG) and premutation (55–200 CGG) alleles have been principally associated with two phenotypes, fragile X tremor ataxia syndrome (FXTAS) and fragile X primary ovarian insufficiency (FXPOI).
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87
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Davenport MH, Schaefer TL, Friedmann KJ, Fitzpatrick SE, Erickson CA. Pharmacotherapy for Fragile X Syndrome: Progress to Date. Drugs 2016; 76:431-45. [PMID: 26858239 DOI: 10.1007/s40265-016-0542-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To date, no drug is approved for the treatment of Fragile X Syndrome (FXS) although many drugs are used to manage challenging behaviors from a symptomatic perspective in this population. While our understanding of FXS pathophysiology is expanding, efforts to devise targeted FXS-specific treatments have had limited success in placebo-controlled trials. Compounds aimed at rectifying excessive glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission, as well as other signaling pathways known to be affected by Fragile X Mental Retardation Protein (FMRP) are under various phases of development in FXS. With the failure of several metabotropic glutamate receptor subtype 5 (mGlur5) selective antagonists under clinical investigation, no clear single treatment appears to be greatly effective. These recent challenges call into question various aspects of clinical study design in FXS. More objective outcome measures are under development and validation. Future trials will likely be aimed at correcting multiple pathways known to be disrupted by the loss of FMRP. This review offers a brief summary of the prevalence, phenotypic characteristics, genetic causes and molecular functions of FMRP in the brain (as these have been extensively reviewed elsewhere), discusses the most recent finding in FXS drug development, and summarizes FXS trials utilizing symptomatic treatment.
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Affiliation(s)
- Matthew H Davenport
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
- Department of Biomedical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Tori L Schaefer
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | - Katherine J Friedmann
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | | | - Craig A Erickson
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA.
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88
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Marín O. Developmental timing and critical windows for the treatment of psychiatric disorders. Nat Med 2016; 22:1229-1238. [PMID: 27783067 DOI: 10.1038/nm.4225] [Citation(s) in RCA: 219] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/05/2016] [Indexed: 02/07/2023]
Abstract
There is a growing understanding that pathological genetic variation and environmental insults during sensitive periods in brain development have long-term consequences on brain function, which range from learning disabilities to complex psychiatric disorders such as schizophrenia. Furthermore, recent experiments in animal models suggest that therapeutic interventions during sensitive periods, typically before the onset of clear neurological and behavioral symptoms, might prevent or ameliorate the development of specific pathologies. These studies suggest that understanding the dynamic nature of the pathophysiological mechanisms underlying psychiatric disorders is crucial for the development of effective therapies. In this Perspective, I explore the emerging concept of developmental windows in psychiatric disorders, their relevance for understanding disease progression and their potential for the design of new therapies. The limitations and caveats of early interventions in psychiatric disorders are also discussed in this context.
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Affiliation(s)
- Oscar Marín
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, United Kingdom
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89
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Wise TL. Changes in insulin-like growth factor signaling alter phenotypes in Fragile X Mice. GENES BRAIN AND BEHAVIOR 2016; 16:241-249. [DOI: 10.1111/gbb.12340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 08/30/2016] [Accepted: 09/09/2016] [Indexed: 12/14/2022]
Affiliation(s)
- T. L. Wise
- Department of Human Genetics; New York State Institute for Basic Research in Developmental Disabilities; Staten Island NY USA
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90
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Westmark CJ, Sokol DK, Maloney B, Lahiri DK. Novel roles of amyloid-beta precursor protein metabolites in fragile X syndrome and autism. Mol Psychiatry 2016; 21:1333-41. [PMID: 27573877 PMCID: PMC5580495 DOI: 10.1038/mp.2016.134] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/20/2016] [Accepted: 06/23/2016] [Indexed: 01/17/2023]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and is associated with up to 5% of autism cases. Several promising drugs are in preclinical testing for FXS; however, bench-to-bedside plans for the clinic are severely limited due to lack of validated biomarkers and outcome measures. Published work from our laboratories has demonstrated altered levels of amyloid-beta (Aβ) precursor protein (APP) and its metabolites in FXS and idiopathic autism. Westmark and colleagues have focused on β-secretase (amyloidogenic) processing and the accumulation of Aβ peptides in adult FXS models, whereas Lahiri and Sokol have studied α-secretase (non-amyloidogenic or anabolic) processing and altered levels of sAPPα and Aβ in pediatric autism and FXS. Thus, our groups have hypothesized a pivotal role for these Alzheimer's disease (AD)-related proteins in the neurodevelopmental disorders of FXS and autism. In this review, we discuss the contribution of APP metabolites to FXS and autism pathogenesis as well as the potential use of these metabolites as blood-based biomarkers and therapeutic targets. Our future focus is to identify key underlying mechanisms through which APP metabolites contribute to FXS and autism condition-to-disease pathology. Positive outcomes will support utilizing APP metabolites as blood-based biomarkers in clinical trials as well as testing drugs that modulate APP processing as potential disease therapeutics. Our studies to understand the role of APP metabolites in developmental conditions such as FXS and autism are a quantum leap for the neuroscience field, which has traditionally restricted any role of APP to AD and aging.
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Affiliation(s)
- Cara J. Westmark
- University of Wisconsin, Department of Neurology, Madison, WI, USA
| | - Deborah K. Sokol
- Indiana University School of Medicine, Department of Psychiatry, Institute of Psychiatric Research, Indianapolis, IN USA
| | - Bryan Maloney
- Indiana University School of Medicine, Department of Psychiatry, Institute of Psychiatric Research, Indianapolis, IN USA
| | - Debomoy K. Lahiri
- Indiana University School of Medicine, Department of Psychiatry, Institute of Psychiatric Research, Indianapolis, IN USA
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91
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Arsenault J, Gholizadeh S, Niibori Y, Pacey LK, Halder SK, Koxhioni E, Konno A, Hirai H, Hampson DR. FMRP Expression Levels in Mouse Central Nervous System Neurons Determine Behavioral Phenotype. Hum Gene Ther 2016; 27:982-996. [PMID: 27604541 PMCID: PMC5178026 DOI: 10.1089/hum.2016.090] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fragile X mental retardation protein (FMRP) is absent or highly reduced in Fragile X Syndrome, a genetic disorder causing cognitive impairment and autistic behaviors. Previous proof-of-principle studies have demonstrated that restoring FMRP in the brain using viral vectors can improve pathological abnormalities in mouse models of fragile X. However, unlike small molecule drugs where the dose can readily be adjusted during treatment, viral vector–based biological therapeutic drugs present challenges in terms of achieving optimal dosing and expression levels. The objective of this study was to investigate the consequences of expressing varying levels of FMRP selectively in neurons of Fmr1 knockout and wild-type (WT) mice. A wide range of neuronal FMRP transgene levels was achieved in individual mice after intra-cerebroventricular administration of adeno-associated viral vectors coding for FMRP. In all treated knockout mice, prominent FMRP transgene expression was observed in forebrain structures, whereas lower levels were present in more caudal regions of the brain. Reduced levels of the synaptic protein PSD-95, elevated levels of the transcriptional modulator MeCP2, and abnormal motor activity, anxiety, and acoustic startle responses in Fmr1 knockout mice were fully or partially rescued after expression of FMRP at about 35–115% of WT expression, depending on the brain region examined. In the WT mouse, moderate FMRP over-expression of up to about twofold had little or no effect on PSD-95 and MeCP2 levels or on behavioral endophenotypes. In contrast, excessive over-expression in the Fmr1 knockout mouse forebrain (approximately 2.5–6-fold over WT) induced pathological motor hyperactivity and suppressed the startle response relative to WT mice. These results delineate a range of FMRP expression levels in the central nervous system that confer phenotypic improvement in fragile X mice. Collectively, these findings are pertinent to the development of long-term curative gene therapy strategies for treating Fragile X Syndrome and other neurodevelopmental disorders.
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Affiliation(s)
- Jason Arsenault
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Shervin Gholizadeh
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Yosuke Niibori
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Laura K Pacey
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Sebok K Halder
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Enea Koxhioni
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Ayumu Konno
- 2 Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Hirokazu Hirai
- 2 Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - David R Hampson
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.,3 Department of Pharmacology, Faculty of Medicine, University of Toronto , Toronto, Ontario, Canada
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92
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Bostrom C, Yau SY, Majaess N, Vetrici M, Gil-Mohapel J, Christie BR. Hippocampal dysfunction and cognitive impairment in Fragile-X Syndrome. Neurosci Biobehav Rev 2016; 68:563-574. [DOI: 10.1016/j.neubiorev.2016.06.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 01/03/2023]
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93
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Advancing the understanding of autism disease mechanisms through genetics. Nat Med 2016; 22:345-61. [PMID: 27050589 DOI: 10.1038/nm.4071] [Citation(s) in RCA: 518] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 02/26/2016] [Indexed: 12/11/2022]
Abstract
Progress in understanding the genetic etiology of autism spectrum disorders (ASD) has fueled remarkable advances in our understanding of its potential neurobiological mechanisms. Yet, at the same time, these findings highlight extraordinary causal diversity and complexity at many levels ranging from molecules to circuits and emphasize the gaps in our current knowledge. Here we review current understanding of the genetic architecture of ASD and integrate genetic evidence, neuropathology and studies in model systems with how they inform mechanistic models of ASD pathophysiology. Despite the challenges, these advances provide a solid foundation for the development of rational, targeted molecular therapies.
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94
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Achuta VS, Grym H, Putkonen N, Louhivuori V, Kärkkäinen V, Koistinaho J, Roybon L, Castrén ML. Metabotropic glutamate receptor 5 responses dictate differentiation of neural progenitors to NMDA-responsive cells in fragile X syndrome. Dev Neurobiol 2016; 77:438-453. [PMID: 27411166 DOI: 10.1002/dneu.22419] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/14/2016] [Accepted: 07/12/2016] [Indexed: 01/04/2023]
Abstract
Disrupted metabotropic glutamate receptor 5 (mGluR5) signaling is implicated in many neuropsychiatric disorders, including autism spectrum disorder, found in fragile X syndrome (FXS). Here we report that intracellular calcium responses to the group I mGluR agonist (S)-3,5-dihydroxyphenylglycine (DHPG) are augmented, and calcium-dependent mGluR5-mediated mechanisms alter the differentiation of neural progenitors in neurospheres derived from human induced pluripotent FXS stem cells and the brains of mouse model of FXS. Treatment with the mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) prevents an abnormal clustering of DHPG-responsive cells that are responsive to activation of ionotropic receptors in mouse FXS neurospheres. MPEP also corrects morphological defects of differentiated cells and enhanced migration of neuron-like cells in mouse FXS neurospheres. Unlike in mouse neurospheres, MPEP increases the differentiation of DHPG-responsive radial glial cells as well as the subpopulation of cells responsive to both DHPG and activation of ionotropic receptors in human neurospheres. However, MPEP normalizes the FXS-specific increase in the differentiation of cells responsive only to N-methyl-d-aspartate (NMDA) present in human neurospheres. Exposure to MPEP prevents the accumulation of intermediate basal progenitors in embryonic FXS mouse brain suggesting that rescue effects of GluR5 antagonist are progenitor type-dependent and species-specific differences of basal progenitors may modify effects of MPEP on the cortical development. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 419-437, 2017.
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Affiliation(s)
- Venkat Swaroop Achuta
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Heli Grym
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Noora Putkonen
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Verna Louhivuori
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland
| | - Virve Kärkkäinen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Jari Koistinaho
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Laurent Roybon
- Stem Cell Laboratory for CNS Disease Modeling, Department of Experimental Medical Science, Lund University, BMC A10, Sölvegatan 19, Lund, SE-221 84, Sweden
| | - Maija L Castrén
- Faculty of Medicine, Physiology, University of Helsinki, P.O. Box 63, Helsinki, FIN, 00014, Finland.,Autism Foundation, Kuortaneenkatu 7B, Helsinki, FI-00520, Finland
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95
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Choi CH, Schoenfeld BP, Bell AJ, Hinchey J, Rosenfelt C, Gertner MJ, Campbell SR, Emerson D, Hinchey P, Kollaros M, Ferrick NJ, Chambers DB, Langer S, Sust S, Malik A, Terlizzi AM, Liebelt DA, Ferreiro D, Sharma A, Koenigsberg E, Choi RJ, Louneva N, Arnold SE, Featherstone RE, Siegel SJ, Zukin RS, McDonald TV, Bolduc FV, Jongens TA, McBride SMJ. Multiple Drug Treatments That Increase cAMP Signaling Restore Long-Term Memory and Aberrant Signaling in Fragile X Syndrome Models. Front Behav Neurosci 2016; 10:136. [PMID: 27445731 PMCID: PMC4928101 DOI: 10.3389/fnbeh.2016.00136] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/15/2016] [Indexed: 01/01/2023] Open
Abstract
Fragile X is the most common monogenic disorder associated with intellectual disability (ID) and autism spectrum disorders (ASD). Additionally, many patients are afflicted with executive dysfunction, ADHD, seizure disorder and sleep disturbances. Fragile X is caused by loss of FMRP expression, which is encoded by the FMR1 gene. Both the fly and mouse models of fragile X are also based on having no functional protein expression of their respective FMR1 homologs. The fly model displays well defined cognitive impairments and structural brain defects and the mouse model, although having subtle behavioral defects, has robust electrophysiological phenotypes and provides a tool to do extensive biochemical analysis of select brain regions. Decreased cAMP signaling has been observed in samples from the fly and mouse models of fragile X as well as in samples derived from human patients. Indeed, we have previously demonstrated that strategies that increase cAMP signaling can rescue short term memory in the fly model and restore DHPG induced mGluR mediated long term depression (LTD) in the hippocampus to proper levels in the mouse model (McBride et al., 2005; Choi et al., 2011, 2015). Here, we demonstrate that the same three strategies used previously with the potential to be used clinically, lithium treatment, PDE-4 inhibitor treatment or mGluR antagonist treatment can rescue long term memory in the fly model and alter the cAMP signaling pathway in the hippocampus of the mouse model.
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Affiliation(s)
- Catherine H Choi
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Department of Dermatology, Dermatology Clinic, Drexel University College of MedicinePhiladelphia, PA, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Brian P Schoenfeld
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Aaron J Bell
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Joseph Hinchey
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Cory Rosenfelt
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Michael J Gertner
- Zukin Laboratory, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Sean R Campbell
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Danielle Emerson
- Jongens Laboratory, Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Paul Hinchey
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Maria Kollaros
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Neal J Ferrick
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
| | - Daniel B Chambers
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Steven Langer
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Steven Sust
- Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Aatika Malik
- Jongens Laboratory, Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Allison M Terlizzi
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - David A Liebelt
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - David Ferreiro
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Ali Sharma
- Zukin Laboratory, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Eric Koenigsberg
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Richard J Choi
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Natalia Louneva
- Arnold Laboratory, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Steven E Arnold
- Arnold Laboratory, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Robert E Featherstone
- Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Steven J Siegel
- Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - R Suzanne Zukin
- Zukin Laboratory, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Thomas V McDonald
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA
| | - Francois V Bolduc
- Bolduc Laboratory, Department of Pediatrics, Center for Neuroscience, University of Alberta Edmonton, AB, Canada
| | - Thomas A Jongens
- Jongens Laboratory, Department of Genetics, University of Pennsylvania School of Medicine Philadelphia, PA, USA
| | - Sean M J McBride
- McDonald Laboratory, Section of Molecular Cardiology, Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Yeshiva UniversityBronx, NY, USA; Jongens Laboratory, Department of Genetics, University of Pennsylvania School of MedicinePhiladelphia, PA, USA; Siegel Laboratory, Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania School of MedicinePhiladelphia, PA, USA
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96
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Selective Disruption of Metabotropic Glutamate Receptor 5-Homer Interactions Mimics Phenotypes of Fragile X Syndrome in Mice. J Neurosci 2016; 36:2131-47. [PMID: 26888925 DOI: 10.1523/jneurosci.2921-15.2016] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Altered function of the Gq-coupled, Group 1 metabotropic glutamate receptors, specifically mGlu5, is implicated in multiple mouse models of autism and intellectual disability. mGlu5 dysfunction has been most well characterized in the fragile X syndrome mouse model, the Fmr1 knock-out (KO) mouse, where pharmacological and genetic reduction of mGlu5 reverses many phenotypes. mGlu5 is less associated with its scaffolding protein Homer in Fmr1 KO mice, and restoration of mGlu5-Homer interactions by genetic deletion of a short, dominant negative of Homer, H1a, rescues many phenotypes of Fmr1 KO mice. These results suggested that disruption of mGlu5-Homer leads to phenotypes of FXS. To test this idea, we examined mice with a knockin mutation of mGlu5 (F1128R; mGlu5(R/R)) that abrogates binding to Homer. Although FMRP levels were normal, mGlu5(R/R) mice mimicked multiple phenotypes of Fmr1 KO mice, including reduced mGlu5 association with the postsynaptic density, enhanced constitutive mGlu5 signaling to protein synthesis, deficits in agonist-induced translational control, protein synthesis-independent LTD, neocortical hyperexcitability, audiogenic seizures, and altered behaviors, including anxiety and sensorimotor gating. These results reveal new roles for the Homer scaffolds in regulation of mGlu5 function and implicate a specific molecular mechanism in a complex brain disease. SIGNIFICANCE STATEMENT Abnormal function of the metabotropic, or Gq-coupled, glutamate receptor 5 (mGlu5) has been implicated in neurodevelopmental disorders, including a genetic cause of intellectual disability and autism called fragile X syndrome. In brains of a mouse model of fragile X, mGlu5 is less associated with its binding partner Homer, a scaffolding protein that regulates mGlu5 localization to synapses and its ability to activate biochemical signaling pathways. Here we show that a mouse expressing a mutant mGlu5 that cannot bind to Homer is sufficient to mimic many of the biochemical, neurophysiological, and behavioral symptoms observed in the fragile X mouse. This work provides strong evidence that Homer-mGlu5 binding contributes to symptoms associated with neurodevelopmental disorders.
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Impairments in dendrite morphogenesis as etiology for neurodevelopmental disorders and implications for therapeutic treatments. Neurosci Biobehav Rev 2016; 68:946-978. [PMID: 27143622 DOI: 10.1016/j.neubiorev.2016.04.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 04/13/2016] [Accepted: 04/13/2016] [Indexed: 02/08/2023]
Abstract
Dendrite morphology is pivotal for neural circuitry functioning. While the causative relationship between small-scale dendrite morphological abnormalities (shape, density of dendritic spines) and neurodevelopmental disorders is well established, such relationship remains elusive for larger-scale dendrite morphological impairments (size, shape, branching pattern of dendritic trees). Here, we summarize published data on dendrite morphological irregularities in human patients and animal models for neurodevelopmental disorders, with focus on autism and schizophrenia. We next discuss high-risk genes for these disorders and their role in dendrite morphogenesis. We finally overview recent developments in therapeutic attempts and we discuss how they relate to dendrite morphology. We find that both autism and schizophrenia are accompanied by dendritic arbor morphological irregularities, and that majority of their high-risk genes regulate dendrite morphogenesis. Thus, we present a compelling argument that, along with smaller-scale morphological impairments in dendrites (spines and synapse), irregularities in larger-scale dendrite morphology (arbor shape, size) may be an important part of neurodevelopmental disorders' etiology. We suggest that this should not be ignored when developing future therapeutic treatments.
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98
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McCammon JM, Sive H. Challenges in understanding psychiatric disorders and developing therapeutics: a role for zebrafish. Dis Model Mech 2016; 8:647-56. [PMID: 26092527 PMCID: PMC4486859 DOI: 10.1242/dmm.019620] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The treatment of psychiatric disorders presents three major challenges to the research and clinical community: defining a genotype associated with a disorder, characterizing the molecular pathology of each disorder and developing new therapies. This Review addresses how cellular and animal systems can help to meet these challenges, with an emphasis on the role of the zebrafish. Genetic changes account for a large proportion of psychiatric disorders and, as gene variants that predispose to psychiatric disease are beginning to be identified in patients, these are tractable for study in cellular and animal systems. Defining cellular and molecular criteria associated with each disorder will help to uncover causal physiological changes in patients and will lead to more objective diagnostic criteria. These criteria should also define co-morbid pathologies within the nervous system or in other organ systems. The definition of genotypes and of any associated pathophysiology is integral to the development of new therapies. Cell culture-based approaches can address these challenges by identifying cellular pathology and by high-throughput screening of gene variants and potential therapeutics. Whole-animal systems can define the broadest function of disorder-associated gene variants and the organismal impact of candidate medications. Given its evolutionary conservation with humans and its experimental tractability, the zebrafish offers several advantages to psychiatric disorder research. These include assays ranging from molecular to behavioural, and capability for chemical screening. There is optimism that the multiple approaches discussed here will link together effectively to provide new diagnostics and treatments for psychiatric patients. Summary: In this review, we discuss strengths and limitations of prevalent laboratory models that are used for understanding psychiatric disorders and developing therapeutics, with emphasis on the zebrafish.
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Affiliation(s)
- Jasmine M McCammon
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Hazel Sive
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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99
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Ohashi R, Takao K, Miyakawa T, Shiina N. Comprehensive behavioral analysis of RNG105 (Caprin1) heterozygous mice: Reduced social interaction and attenuated response to novelty. Sci Rep 2016; 6:20775. [PMID: 26865403 PMCID: PMC4749962 DOI: 10.1038/srep20775] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/07/2016] [Indexed: 01/16/2023] Open
Abstract
RNG105 (also known as Caprin1) is a major RNA-binding protein in neuronal RNA granules, and is responsible for mRNA transport to dendrites and neuronal network formation. A recent study reported that a heterozygous mutation in the Rng105 gene was found in an autism spectrum disorder (ASD) patient, but it remains unclear whether there is a causal relation between RNG105 deficiency and ASD. Here, we subjected Rng105(+/-) mice to a comprehensive behavioral test battery, and revealed the influence of RNG105 deficiency on mouse behavior. Rng105(+/-) mice exhibited a reduced sociality in a home cage and a weak preference for social novelty. Consistently, the Rng105(+/-) mice also showed a weak preference for novel objects and novel place patterns. Furthermore, although the Rng105(+/-) mice exhibited normal memory acquisition, they tended to have relative difficulty in reversal learning in the spatial reference tasks. These findings suggest that the RNG105 heterozygous knockout leads to a reduction in sociality, response to novelty and flexibility in learning, which are implicated in ASD-like behavior.
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Affiliation(s)
- Rie Ohashi
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi, Japan.,Department of Basic Biology, SOKENDAI, Okazaki, Aichi, Japan
| | - Keizo Takao
- Section of Behavior Patterns, National Institute for Physical Science, Okazaki, Aichi, Japan.,Department of Physiology, SOKENDAI, Okazaki, Aichi, Japan.,Division of Animal Resources and Development, Life Science Research Center, University of Toyama, Toyama, Japan
| | - Tsuyoshi Miyakawa
- Section of Behavior Patterns, National Institute for Physical Science, Okazaki, Aichi, Japan.,Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Nobuyuki Shiina
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi, Japan.,Department of Basic Biology, SOKENDAI, Okazaki, Aichi, Japan.,Okazaki Institute for Integrative Bioscience, Okazaki, Aichi, Japan
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100
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Enriquez-Barreto L, Morales M. The PI3K signaling pathway as a pharmacological target in Autism related disorders and Schizophrenia. MOLECULAR AND CELLULAR THERAPIES 2016; 4:2. [PMID: 26877878 PMCID: PMC4751644 DOI: 10.1186/s40591-016-0047-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 01/25/2016] [Indexed: 01/01/2023]
Abstract
This review is focused in PI3K’s involvement in two widespread mental disorders: Autism and Schizophrenia. A large body of evidence points to synaptic dysfunction as a cause of these diseases, either during the initial phases of brain synaptic circuit’s development or later modulating synaptic function and plasticity. Autism related disorders and Schizophrenia are complex genetic conditions in which the identification of gene markers has proved difficult, although the existence of single-gene mutations with a high prevalence in both diseases offers insight into the role of the PI3K signaling pathway. In the brain, components of the PI3K pathway regulate synaptic formation and plasticity; thus, disruption of this pathway leads to synapse dysfunction and pathological behaviors. Here, we recapitulate recent evidences that demonstrate the imbalance of several PI3K elements as leading causes of Autism and Schizophrenia, together with the plausible new pharmacological paths targeting this signaling pathway.
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Affiliation(s)
- Lilian Enriquez-Barreto
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Miguel Morales
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
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