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Leone R, Zuglian C, Brambilla R, Morella I. Understanding copy number variations through their genes: a molecular view on 16p11.2 deletion and duplication syndromes. Front Pharmacol 2024; 15:1407865. [PMID: 38948459 PMCID: PMC11211608 DOI: 10.3389/fphar.2024.1407865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 05/16/2024] [Indexed: 07/02/2024] Open
Abstract
Neurodevelopmental disorders (NDDs) include a broad spectrum of pathological conditions that affect >4% of children worldwide, share common features and present a variegated genetic origin. They include clinically defined diseases, such as autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder (ADHD), motor disorders such as Tics and Tourette's syndromes, but also much more heterogeneous conditions like intellectual disability (ID) and epilepsy. Schizophrenia (SCZ) has also recently been proposed to belong to NDDs. Relatively common causes of NDDs are copy number variations (CNVs), characterised by the gain or the loss of a portion of a chromosome. In this review, we focus on deletions and duplications at the 16p11.2 chromosomal region, associated with NDDs, ID, ASD but also epilepsy and SCZ. Some of the core phenotypes presented by human carriers could be recapitulated in animal and cellular models, which also highlighted prominent neurophysiological and signalling alterations underpinning 16p11.2 CNVs-associated phenotypes. In this review, we also provide an overview of the genes within the 16p11.2 locus, including those with partially known or unknown function as well as non-coding RNAs. A particularly interesting interplay was observed between MVP and MAPK3 in modulating some of the pathological phenotypes associated with the 16p11.2 deletion. Elucidating their role in intracellular signalling and their functional links will be a key step to devise novel therapeutic strategies for 16p11.2 CNVs-related syndromes.
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Affiliation(s)
- Roberta Leone
- Università di Pavia, Dipartimento di Biologia e Biotecnologie “Lazzaro Spallanzani”, Pavia, Italy
| | - Cecilia Zuglian
- Università di Pavia, Dipartimento di Biologia e Biotecnologie “Lazzaro Spallanzani”, Pavia, Italy
| | - Riccardo Brambilla
- Università di Pavia, Dipartimento di Biologia e Biotecnologie “Lazzaro Spallanzani”, Pavia, Italy
- Cardiff University, School of Biosciences, Neuroscience and Mental Health Innovation Institute, Cardiff, United Kingdom
| | - Ilaria Morella
- Cardiff University, School of Biosciences, Neuroscience and Mental Health Innovation Institute, Cardiff, United Kingdom
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Bataveljic D, Pivonkova H, de Concini V, Hébert B, Ezan P, Briault S, Bemelmans AP, Pichon J, Menuet A, Rouach N. Astroglial Kir4.1 potassium channel deficit drives neuronal hyperexcitability and behavioral defects in Fragile X syndrome mouse model. Nat Commun 2024; 15:3583. [PMID: 38678030 PMCID: PMC11055954 DOI: 10.1038/s41467-024-47681-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 04/03/2024] [Indexed: 04/29/2024] Open
Abstract
Fragile X syndrome (FXS) is an inherited form of intellectual disability caused by the loss of the mRNA-binding fragile X mental retardation protein (FMRP). FXS is characterized by neuronal hyperexcitability and behavioral defects, however the mechanisms underlying these critical dysfunctions remain unclear. Here, using male Fmr1 knockout mouse model of FXS, we identify abnormal extracellular potassium homeostasis, along with impaired potassium channel Kir4.1 expression and function in astrocytes. Further, we reveal that Kir4.1 mRNA is a binding target of FMRP. Finally, we show that the deficit in astroglial Kir4.1 underlies neuronal hyperexcitability and several behavioral defects in Fmr1 knockout mice. Viral delivery of Kir4.1 channels specifically to hippocampal astrocytes from Fmr1 knockout mice indeed rescues normal astrocyte potassium uptake, neuronal excitability, and cognitive and social performance. Our findings uncover an important role for astrocyte dysfunction in the pathophysiology of FXS, and identify Kir4.1 channel as a potential therapeutic target for FXS.
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Affiliation(s)
- Danijela Bataveljic
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Helena Pivonkova
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Department of Physiology, 2nd Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Vidian de Concini
- Experimental and Molecular Immunology and Neurogenetics, CNRS UMR7355 and Orléans University, Orléans, France
| | - Betty Hébert
- Experimental and Molecular Immunology and Neurogenetics, CNRS UMR7355 and Orléans University, Orléans, France
| | - Pascal Ezan
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Sylvain Briault
- Experimental and Molecular Immunology and Neurogenetics, CNRS UMR7355 and Orléans University, Orléans, France
- Department of Genetics, Regional Hospital, Orléans, France
| | - Alexis-Pierre Bemelmans
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale, Institut de biologie François Jacob, MIRCen, and CNRS UMR 9199, Université Paris-Sud, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses, 92260, France
| | - Jacques Pichon
- Experimental and Molecular Immunology and Neurogenetics, CNRS UMR7355 and Orléans University, Orléans, France
| | - Arnaud Menuet
- Experimental and Molecular Immunology and Neurogenetics, CNRS UMR7355 and Orléans University, Orléans, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France.
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Deloulme JC, Leclercq M, Deschaux O, Flore G, Capellano L, Tocco C, Braz BY, Studer M, Lahrech H. Structural interhemispheric connectivity defects in mouse models of BBSOAS: Insights from high spatial resolution 3D white matter tractography. Neurobiol Dis 2024; 193:106455. [PMID: 38408685 DOI: 10.1016/j.nbd.2024.106455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/23/2024] [Accepted: 02/23/2024] [Indexed: 02/28/2024] Open
Abstract
White matter (WM) tract formation and axonal pathfinding are major processes in brain development allowing to establish precise connections between targeted structures. Disruptions in axon pathfinding and connectivity impairments will lead to neural circuitry abnormalities, often associated with various neurodevelopmental disorders (NDDs). Among several neuroimaging methodologies, Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) technique that has the advantage of visualizing in 3D the WM tractography of the whole brain non-invasively. DTI is particularly valuable in unpinning structural tract connectivity defects of neural networks in NDDs. In this study, we used 3D DTI to unveil brain-specific tract defects in two mouse models lacking the Nr2f1 gene, which mutations in patients have been proven to cause an emerging NDD, called Bosch-Boonstra-Schaaf Optic Atrophy (BBSOAS). We aimed to investigate the impact of the lack of cortical Nr2f1 function on WM morphometry and tract microstructure quantifications. We found in both mutant mice partial loss of fibers and severe misrouting of the two major cortical commissural tracts, the corpus callosum, and the anterior commissure, as well as the two major hippocampal efferent tracts, the post-commissural fornix, and the ventral hippocampal commissure. DTI tract malformations were supported by 2D histology, 3D fluorescent imaging, and behavioral analyses. We propose that these interhemispheric connectivity impairments are consistent in explaining some cognitive defects described in BBSOAS patients, particularly altered information processing between the two brain hemispheres. Finally, our results highlight 3DDTI as a relevant neuroimaging modality that can provide appropriate morphometric biomarkers for further diagnosis of BBSOAS patients.
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Affiliation(s)
| | | | - Olivier Deschaux
- University Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France
| | - Gemma Flore
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso", CNR, Napoli, Italy
| | - Laetitia Capellano
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institute Neurosciences, 38000 Grenoble, France
| | - Chiara Tocco
- University Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France
| | - Barbara Yael Braz
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institute Neurosciences, 38000 Grenoble, France
| | - Michèle Studer
- University Côte d'Azur (UCA), CNRS, Inserm, Institute of Biology Valrose (iBV), Nice, France.
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Sharghi S, Flunkert S, Daurer M, Rabl R, Chagnaud BP, Leopoldo M, Lacivita E, Hutter-Paier B, Prokesch M. Evaluating the effect of R-Baclofen and LP-211 on autistic behavior of the BTBR and Fmr1-KO mouse models. Front Neurosci 2023; 17:1087788. [PMID: 37065917 PMCID: PMC10097904 DOI: 10.3389/fnins.2023.1087788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
IntroductionAutism spectrum disorder (ASD) is a persistent neurodevelopmental condition characterized by two core behavioral symptoms: impaired social communication and interaction, as well as stereotypic, repetitive behavior. No distinct cause of ASD is known so far; however, excitatory/inhibitory imbalance and a disturbed serotoninergic transmission have been identified as prominent candidates responsible for ASD etiology.MethodsThe GABAB receptor agonist R-Baclofen and the selective agonist for the 5HT7 serotonin receptor LP-211 have been reported to correct social deficits and repetitive behaviors in mouse models of ASD. To evaluate the efficacy of these compounds in more details, we treated BTBR T+ Itpr3tf/J and B6.129P2-Fmr1tm1Cgr/J mice acutely with R-Baclofen or LP-211 and evaluated the behavior of animals in a series of tests.ResultsBTBR mice showed motor deficits, elevated anxiety, and highly repetitive behavior of self-grooming. Fmr1-KO mice exhibited decreased anxiety and hyperactivity. Additionally, Fmr1-KO mice’s ultrasonic vocalizations were impaired suggesting a reduced social interest and communication of this strain. Acute LP-211 administration did not affect the behavioral abnormalities observed in BTBR mice but improved repetitive behavior in Fmr1-KO mice and showed a trend to change anxiety of this strain. Acute R-Baclofen treatment improved repetitive behavior only in Fmr1-KO mice.ConclusionOur results add value to the current available data on these mouse models and the respective compounds. Yet, additional studies are needed to further test R-Baclofen and LP-211 as potential treatments for ASD therapy.
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Affiliation(s)
- Shirin Sharghi
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
- Institute for Biology, Karl-Franzens-Universität Graz, Graz, Austria
- *Correspondence: Shirin Sharghi,
| | - Stefanie Flunkert
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
| | - Magdalena Daurer
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
| | - Roland Rabl
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
| | | | - Marcello Leopoldo
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Enza Lacivita
- Department of Pharmacy-Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | | | - Manuela Prokesch
- Department of Neuropharmacology, QPS Austria GmbH, Grambach, Austria
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Liu X, Kumar V, Tsai NP, Auerbach BD. Hyperexcitability and Homeostasis in Fragile X Syndrome. Front Mol Neurosci 2022; 14:805929. [PMID: 35069112 PMCID: PMC8770333 DOI: 10.3389/fnmol.2021.805929] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/14/2021] [Indexed: 01/13/2023] Open
Abstract
Fragile X Syndrome (FXS) is a leading inherited cause of autism and intellectual disability, resulting from a mutation in the FMR1 gene and subsequent loss of its protein product FMRP. Despite this simple genetic origin, FXS is a phenotypically complex disorder with a range of physical and neurocognitive disruptions. While numerous molecular and cellular pathways are affected by FMRP loss, there is growing evidence that circuit hyperexcitability may be a common convergence point that can account for many of the wide-ranging phenotypes seen in FXS. The mechanisms for hyperexcitability in FXS include alterations to excitatory synaptic function and connectivity, reduced inhibitory neuron activity, as well as changes to ion channel expression and conductance. However, understanding the impact of FMR1 mutation on circuit function is complicated by the inherent plasticity in neural circuits, which display an array of homeostatic mechanisms to maintain activity near set levels. FMRP is also an important regulator of activity-dependent plasticity in the brain, meaning that dysregulated plasticity can be both a cause and consequence of hyperexcitable networks in FXS. This makes it difficult to separate the direct effects of FMR1 mutation from the myriad and pleiotropic compensatory changes associated with it, both of which are likely to contribute to FXS pathophysiology. Here we will: (1) review evidence for hyperexcitability and homeostatic plasticity phenotypes in FXS models, focusing on similarities/differences across brain regions, cell-types, and developmental time points; (2) examine how excitability and plasticity disruptions interact with each other to ultimately contribute to circuit dysfunction in FXS; and (3) discuss how these synaptic and circuit deficits contribute to disease-relevant behavioral phenotypes like epilepsy and sensory hypersensitivity. Through this discussion of where the current field stands, we aim to introduce perspectives moving forward in FXS research.
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Affiliation(s)
- Xiaopeng Liu
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Vipendra Kumar
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Nien-Pei Tsai
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Benjamin D. Auerbach
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Benjamin D. Auerbach
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6
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Jiang S, He M, Xiao L, Sun Y, Ding J, Li W, Guo B, Wang L, Wang Y, Gao C, Sun T, Wang F. Prenatal GABAB Receptor Agonist Administration Corrects the Inheritance of Autism-Like Core Behaviors in Offspring of Mice Prenatally Exposed to Valproic Acid. Front Psychiatry 2022; 13:835993. [PMID: 35492716 PMCID: PMC9051083 DOI: 10.3389/fpsyt.2022.835993] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/07/2022] [Indexed: 12/21/2022] Open
Abstract
This study was performed to evaluate the effects of prenatal baclofen (a GABAB receptor agonist) treatment on the inheritance of autism-like behaviors in valproic acid (VPA)-exposed mice. VPA model mice (first generation, F1) that were prenatally exposed to VPA exhibited robust core autism-like behaviors, and we found that oral administration of baclofen to F1 mice corrected their autism-like behavioral phenotypes at an early age. Based on a previous epigenetics study, we mated the F1 male offspring with litter females to produce the second generation (F2). The F2 male mice showed obvious inheritance of autism-like phenotypes from F1 mice, implying the heritability of autism symptoms in patients with prenatal VPA exposure. Furthermore, we found prenatal baclofen administration was associated with beneficial effects on the autism-like phenotype in F2 male mice. This may have involved corrections in the density of total/mature dendritic spines in the hippocampus (HC) and medial prefrontal cortex (mPFC), normalizing synaptic plasticity. In this research, GABAB receptor agonist administration corrected the core autism-like behaviors of F1 mice and protected against the inheritance of neurodevelopmental disorders in the offspring of F1 mice, suggesting the potential of early intervention with GABAB receptor agonists in the treatment of neurodevelopmental disorders.
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Affiliation(s)
- Shucai Jiang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Maotao He
- School of Basic Medical Sciences, Weifang Medical University, Weifang, China
| | - Lifei Xiao
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Yu Sun
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Jiangwei Ding
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Wenchao Li
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Baorui Guo
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Lei Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Yangyang Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Caibin Gao
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Tao Sun
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Feng Wang
- Ningxia Key Laboratory of Craniocerebral Disease, Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China.,The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Abstract
GABAB receptors are implicated in numerous central nervous system-based behaviours and mechanisms, including cognitive processing in preclinical animal models. Homeostatic changes in the expression and function of these receptors across brain structures have been found to affect cognitive processing. Numerous preclinical studies have focused on the role of GABAB receptors in learning, memory and cognition per se with some interesting, although sometimes contradictory, findings. The majority of the existing clinical literature focuses on alterations in GABAB receptor function in conditions and disorders whose main symptomatology includes deficits in cognitive processing. The aim of this chapter is to delineate the role of GABAB receptors in cognitive processes in health and disease of animal models and human clinical populations. More specifically, this review aims to present literature on the role of GABAB receptors in animal models with cognitive deficits, especially those of learning and memory. Further, it aims to capture the progress and advances of research studies on the effects of GABAB receptor compounds in neurodevelopmental and neurodegenerative conditions with cognitive dysfunctions. The neurodevelopmental conditions covered include autism spectrum disorders, fragile X syndrome and Down's syndrome and the neurodegenerative conditions discussed are Alzheimer's disease, epilepsy and autoimmune anti-GABAB encephalitis. Although some findings are contradictory, results indicate a possible therapeutic role of GABAB receptor compounds for the treatment of cognitive dysfunction and learning/memory impairments for some of these conditions, especially in neurodegeneration. Moreover, future research efforts should aim to develop selective GABAB receptor compounds with minimal, if any, side effects.
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8
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Bassetti D, Luhmann HJ, Kirischuk S. Presynaptic GABA B receptor-mediated network excitation in the medial prefrontal cortex of Tsc2 +/- mice. Pflugers Arch 2021; 473:1261-1271. [PMID: 34279736 PMCID: PMC8302497 DOI: 10.1007/s00424-021-02576-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/21/2021] [Accepted: 05/05/2021] [Indexed: 11/02/2022]
Abstract
The TSC1 and TSC2 tumor suppressor genes control the activity of mechanistic target of rapamycin (mTOR) pathway. Elevated activity of this pathway in Tsc2+/- mouse model leads to reduction of postsynaptic GABAB receptor-mediated inhibition and hyperexcitability in the medial prefrontal cortex (mPFC). In this study, we asked whether presynaptic GABAB receptors (GABABRs) can compensate this shift of hyperexcitability. Experiments were performed in brain slices from adolescent wild-type (WT) and Tsc2+/- mice. Miniature and spontaneous postsynaptic currents (m/sPSCs) were recorded from layer 2/3 pyramidal neurons in mPFC using patch-clamp technique using a Cs+-based intrapipette solution. Presynaptic GABABRs were activated by baclofen (10 µM) or blocked by CGP55845 (1 µM). Independent on genotype, GABABR modulators bidirectionally change miniature excitatory postsynaptic current (mEPSC) frequency by about 10%, indicating presynaptic GABABR-mediated effects on glutamatergic transmission are comparable in both genotypes. In contrast, frequencies of both mIPSCs and sIPCSs were suppressed by baclofen stronger in Tsc2+/- neurons than in WT ones, whereas CGP55845 significantly increased (m/s)IPSC frequencies only in WT cells. Effects of baclofen and CGP55845 on the amplitudes of evoked (e)IPSCs confirmed these observations. These data indicate (1) that GABAergic synapses are inhibited by ambient GABA in WT but not in Tsc2+/- slices, and (2) that baclofen shifts the E/I ratio, determined as the ratio of (m/s)EPSC frequency to (m/s)IPSC frequency, towards excitation only in Tsc2+/- cells. This excitatory presynaptic GABABR-mediated action has to be taken into account for a possible medication of mental disorders using baclofen.
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Affiliation(s)
- Davide Bassetti
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany.
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany
| | - Sergei Kirischuk
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany
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Heaney CF, Namjoshi SV, Uneri A, Bach EC, Weiner JL, Raab-Graham KF. Role of FMRP in rapid antidepressant effects and synapse regulation. Mol Psychiatry 2021; 26:2350-2362. [PMID: 33432187 PMCID: PMC8440195 DOI: 10.1038/s41380-020-00977-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 11/23/2020] [Accepted: 12/01/2020] [Indexed: 11/09/2022]
Abstract
Rapid antidepressants are novel treatments for major depressive disorder (MDD) and work by blocking N-methyl-D-aspartate receptors (NMDARs), which, in turn, activate the protein synthesis pathway regulated by mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Our recent work demonstrates that the RNA-binding protein Fragile X Mental Retardation Protein (FMRP) is downregulated in dendrites upon treatment with a rapid antidepressant. Here, we show that the behavioral effects of the rapid antidepressant Ro-25-6981 require FMRP expression, and treatment promotes differential mRNA binding to FMRP in an mTORC1-dependent manner. Further, these mRNAs are identified to regulate transsynaptic signaling. Using a novel technique, we show that synapse formation underlying the behavioral effects of Ro-25-6981 requires GABABR-mediated mTORC1 activity in WT animals. Finally, we demonstrate that in an animal model that lacks FMRP expression and has clinical relevance for Fragile X Syndrome (FXS), GABABR activity is detrimental to the effects of Ro-25-6981. These effects are rescued with the combined therapy of blocking GABABRs and NMDARs, indicating that rapid antidepressants alone may not be an effective treatment for people with comorbid FXS and MDD.
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Affiliation(s)
- Chelcie F Heaney
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Sanjeev V Namjoshi
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Ayse Uneri
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Eva C Bach
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Kimberly F Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
- Wake Forest Translational Alcohol Research Center (WF-TARC), Wake Forest University Health Sciences, 1 Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
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10
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Bassetti D, Lombardi A, Kirischuk S, Luhmann HJ. Haploinsufficiency of Tsc2 Leads to Hyperexcitability of Medial Prefrontal Cortex via Weakening of Tonic GABAB Receptor-mediated Inhibition. Cereb Cortex 2020; 30:6313-6324. [PMID: 32705128 DOI: 10.1093/cercor/bhaa187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 12/30/2022] Open
Abstract
Loss-of-function mutation in one of the tumor suppressor genes TSC1 or TSC2 is associated with several neurological and psychiatric diseases, including autism spectrum disorders (ASDs). As an imbalance between excitatory and inhibitory neurotransmission, E/I ratio is believed to contribute to the development of these disorders, we investigated synaptic transmission during the first postnatal month using the Tsc2+/- mouse model. Electrophysiological recordings were performed in acute brain slices of medial prefrontal cortex. E/I ratio at postnatal day (P) 15-19 is increased in Tsc2+/- mice as compared with wildtype (WT). At P25-30, facilitated GABAergic transmission reduces E/I ratio to the WT level, but weakening of tonic GABAB receptor (GABABR)-mediated inhibition in Tsc2+/- mice leads to hyperexcitability both at single cell and neuronal network level. Short (1 h) preincubation of P25-30 Tsc2+/- slices with baclofen restores the GABABR-mediated inhibition and reduces network excitability. Interestingly, the same treatment at P15-19 leads to weakening of GABABR-mediated inhibition. We hypothesize that a dysfunction of tonic GABABR-mediated inhibition might contribute to the development of ASD symptoms and suggest that GABABR activation within an appropriate time window may be considered as a therapeutic target in ASD.
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Affiliation(s)
- Davide Bassetti
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
| | - Aniello Lombardi
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
| | - Sergei Kirischuk
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz D-55128, Germany
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Telias M. Pharmacological Treatments for Fragile X Syndrome Based on Synaptic Dysfunction. Curr Pharm Des 2020; 25:4394-4404. [PMID: 31682210 DOI: 10.2174/1381612825666191102165206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 10/31/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common form of monogenic hereditary cognitive impairment, including intellectual disability, autism, hyperactivity, and epilepsy. METHODS This article reviews the literature pertaining to the role of synaptic dysfunction in FXS. RESULTS In FXS, synaptic dysfunction alters the excitation-inhibition ratio, dysregulating molecular and cellular processes underlying cognition, learning, memory, and social behavior. Decades of research have yielded important hypotheses that could explain, at least in part, the development of these neurological disorders in FXS patients. However, the main goal of translating lab research in animal models to pharmacological treatments in the clinic has been so far largely unsuccessful, leaving FXS a still incurable disease. CONCLUSION In this concise review, we summarize and analyze the main hypotheses proposed to explain synaptic dysregulation in FXS, by reviewing the scientific evidence that led to pharmaceutical clinical trials and their outcome.
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Affiliation(s)
- Michael Telias
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
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Zeidler S, Pop AS, Jaafar IA, de Boer H, Buijsen RAM, de Esch CEF, Nieuwenhuizen‐Bakker I, Hukema RK, Willemsen R. Paradoxical effect of baclofen on social behavior in the fragile X syndrome mouse model. Brain Behav 2018; 8:e00991. [PMID: 29785777 PMCID: PMC5991574 DOI: 10.1002/brb3.991] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/29/2018] [Accepted: 03/31/2018] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Fragile X syndrome (FXS) is a common monogenetic cause of intellectual disability, autism spectrum features, and a broad range of other psychiatric and medical problems. FXS is caused by the lack of the fragile X mental retardation protein (FMRP), a translational regulator of specific mRNAs at the postsynaptic compartment. The absence of FMRP leads to aberrant synaptic plasticity, which is believed to be caused by an imbalance in excitatory and inhibitory network functioning of the synapse. Evidence from studies in mice demonstrates that GABA, the major inhibitory neurotransmitter in the brain, and its receptors, is involved in the pathogenesis of FXS. Moreover, several FXS phenotypes, including social behavior deficits, could be corrected in Fmr1 KO mice after acute treatment with GABAB agonists. METHODS As FXS would probably require a lifelong treatment, we investigated the effect of chronic treatment with the GABAB agonist baclofen on social behavior in Fmr1 KO mice on two behavioral paradigms for social behavior: the automated tube test and the three-chamber sociability test. RESULTS Unexpectedly, chronic baclofen treatment resulted in worsening of the FXS phenotypes in these behavior tests. Strikingly, baclofen treatment also affected wild-type animals in both behavioral tests, inducing a phenotype similar to that of untreated Fmr1 KO mice. CONCLUSION Altogether, the disappointing results of recent clinical trials with the R-baclofen enantiomer arbaclofen and our current results indicate that baclofen should be reconsidered and further evaluated before its application in targeted treatment for FXS.
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Affiliation(s)
- Shimriet Zeidler
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Andreea S. Pop
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Israa A. Jaafar
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Helen de Boer
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Ronald A. M. Buijsen
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Celine E. F. de Esch
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | | | - Renate K. Hukema
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
| | - Rob Willemsen
- Department of Clinical GeneticsErasmus University Medical CenterRotterdamThe Netherlands
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