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Ferraguto C, Piquemal-Lagoueillat M, Lemaire V, Moreau MM, Trazzi S, Uguagliati B, Ciani E, Bertrand SS, Louette E, Bontempi B, Pietropaolo S. Therapeutic efficacy of the BKCa channel opener chlorzoxazone in a mouse model of Fragile X syndrome. Neuropsychopharmacology 2024; 49:2032-2041. [PMID: 39223257 PMCID: PMC11480417 DOI: 10.1038/s41386-024-01956-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 06/30/2024] [Accepted: 07/23/2024] [Indexed: 09/04/2024]
Abstract
Fragile X syndrome (FXS) is an X-linked neurodevelopmental disorder characterized by several behavioral abnormalities, including hyperactivity, anxiety, sensory hyper-responsiveness, and autistic-like symptoms such as social deficits. Despite considerable efforts, effective pharmacological treatments are still lacking, prompting the need for exploring the therapeutic value of existing drugs beyond their original approved use. One such repurposed drug is chlorzoxazone which is classified as a large-conductance calcium-dependent potassium (BKCa) channel opener. Reduced BKCa channel functionality has been reported in FXS patients, suggesting that molecules activating these channels could serve as promising treatments for this syndrome. Here, we sought to characterize the therapeutic potential of chlorzoxazone using the Fmr1-KO mouse model of FXS which recapitulates the main phenotypes of FXS, including BKCa channel alterations. Chlorzoxazone, administered either acutely or chronically, rescued hyperactivity and acoustic hyper-responsiveness as well as impaired social interactions exhibited by Fmr1-KO mice. Chlorzoxazone was more efficacious in alleviating these phenotypes than gaboxadol and metformin, two repurposed treatments for FXS that do not target BKCa channels. Systemic administration of chlorzoxazone modulated the neuronal activity-dependent gene c-fos in selected brain areas of Fmr1-KO mice, corrected aberrant hippocampal dendritic spines, and was able to rescue impaired BKCa currents recorded from hippocampal and cortical neurons of these mutants. Collectively, these findings provide further preclinical support for BKCa channels as a valuable therapeutic target for treating FXS and encourage the repurposing of chlorzoxazone for clinical applications in FXS and other related neurodevelopmental diseases.
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Affiliation(s)
| | | | - Valerie Lemaire
- Univ. Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux, France
| | - Maïté M Moreau
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Stefania Trazzi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Beatrice Uguagliati
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Elisabetta Ciani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | | | | | - Bruno Bontempi
- Univ. Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux, France
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Janz P, Bainier M, Marashli S, Gross S, Redondo RL. Clinically-probed mechanisms of action in Fragile-X Syndrome fail to normalize translational EEG phenotypes in Fmr1 knockout mice. Neuropharmacology 2024:110182. [PMID: 39396738 DOI: 10.1016/j.neuropharm.2024.110182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2024] [Revised: 09/30/2024] [Accepted: 10/10/2024] [Indexed: 10/15/2024]
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by Fragile X Messenger Ribonucleoprotein (FMRP) deficiency. Electroencephalogram (EEG) changes in FXS include alterations of oscillatory activity and responses to sensory stimuli, some of which have been back-translated into rodent models by knocking-out the Fragile X messenger ribonucleoprotein 1 gene (Fmr1-KO). However, the validity of these EEG phenotypes as objective biomarkers requires further investigation. Potential pharmacotherapies such as mGluR5 inhibitors (e.g. CTEP; 2-chloro-4-((2,5-dimethyl-1-(4-(trifluoromethoxy)phenyl)-1H-imidazol-4-yl)ethynyl)pyridine), GABABR agonists (e.g. arbaclofen) and δ-containing GABAAR agonists (e.g. gaboxadol) have not translated into clinical success despite rescuing many phenotypes in the Fmr1-KO model. Yet none of these treatments have been assessed on EEG phenotypes in the Fmr1-KO model. Therefore, we set out to discover new EEG phenotypes in Fmr1-KO mice, using "task-free" and auditory-evoked (AEPs) and visually-evoked potential (VEP) paradigms, and probe their modulation by CTEP, arbaclofen and gaboxadol, using within-subjects designs. First, we report Fmr1-KO-associated EEG abnormalities that closely resemble those observed in FXS, including elevated gamma-band power, reduced alpha/beta-band coherence, increased AEPs and delayed VEPs. Secondly, we found that pharmacological treatment, at best, only partially normalized EEG phenotypes. CTEP restored alpha/beta-band coherence and AEP amplitudes but failed to normalize gamma power and VEP latencies. Conversely, arbaclofen reduced gamma power but did not restore coherence or AEP amplitudes and further delayed VEPs. Gaboxadol did not normalize any EEG phenotypes. We conclude that these compounds have limited ability to normalize these EEG phenotypes.
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Affiliation(s)
- Philipp Janz
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland.
| | - Marie Bainier
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Samuel Marashli
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Simon Gross
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Roger L Redondo
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
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Zhang W, Liu T, Li J, Singh J, Chan A, Islam A, Petrache A, Peng Y, Harvey K, Ali AB. Decreased extrasynaptic δ-GABA A receptors in PNN-associated parvalbumin interneurons correlates with anxiety in APP and tau mouse models of Alzheimer's disease. Br J Pharmacol 2024; 181:3944-3975. [PMID: 38886118 DOI: 10.1111/bph.16441] [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: 03/15/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is associated with gradual memory loss and anxiety which affects ~75% of AD patients. This study investigated whether AD-associated anxiety correlated with modulation of extrasynaptic δ-subunit-containing GABAA receptors (δ-GABAARs) in experimental mouse models of AD. EXPERIMENTAL APPROACH We combined behavioural experimental paradigms to measure cognition performance, and anxiety with neuroanatomy and molecular biology, using familial knock-in (KI) mouse models of AD that harbour β-amyloid (Aβ) precursor protein App (AppNL-F) with or without humanized microtubule-associated protein tau (MAPT), age-matched to wild-type control mice at three different age windows. RESULTS AppNL-F KI and AppNL-F/MAPT AD models showed a similar magnitude of cognitive decline and elevated magnitude of anxiety correlated with neuroinflammatory hallmarks, including triggering receptor expressed on myeloid cells 2 (TREM2), reactive astrocytes and activated microglia consistent with accumulation of Aβ, tau and down-regulation of Wnt/β-catenin signalling compared to aged-matched WT controls. In both the CA1 region of the hippocampus and dentate gyrus, there was an age-dependent decline in the expression of δ-GABAARs selectively expressed in parvalbumin (PV)-expressing interneurons, encapsulated by perineuronal nets (PNNs) in the AD mouse models compared to WT mice. In vivo positive allosteric modulation of the δ-GABAARs, using a δ-selective-compound DS2, decreased the level of anxiety in the AD mouse models, which was correlated with reduced hallmarks of neuroinflammation, and 'normalisation' of the expression of δ-GABAARs. CONCLUSIONS Our data show that the δ-GABAARs could potentially be targeted for alleviating symptoms of anxiety, which would greatly improve the quality of life of AD individuals.
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Blandin KJ, Narvaiz DA, Sullens DG, Womble PD, Hodges SL, Binder MS, Faust A, Nguyen PH, Pranske ZJ, Lugo JN. A Two-Hit Approach Inducing Flurothyl Seizures in Fmr1 Knockout Mice Impacts Anxiety and Repetitive Behaviors. Brain Sci 2024; 14:892. [PMID: 39335388 PMCID: PMC11429635 DOI: 10.3390/brainsci14090892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2024] [Revised: 08/25/2024] [Accepted: 08/28/2024] [Indexed: 09/30/2024] Open
Abstract
BACKGROUND Fragile X Syndrome (FXS) is the leading monogenetic cause of autism spectrum disorder (ASD) and is associated with seizures. We examined the impact of repeated seizures on the behavioral and molecular changes in male Fmr1 knockout (KO) mice and wild-type (WT) mice. METHODS Seizures were induced by administering three flurothyl seizures per day across postnatal days (PD) 7-11, for a total of 15 seizures. In adulthood, mice were tested in a battery of behavioral tasks to assess long-term behavioral deficits. RESULTS The two-hit impact of a Fmr1 knockout and seizures resulted in decreased anxiety-like behavior in the elevated plus maze test and a longer latency to their first nose poke (repetitive behavior). Seizures resulted in decreased activity, decreased repetitive behavior (grooming and rearings), and decreased social behavior, while they also increased habituation to auditory stimuli and increased freezing in delayed fear conditioning in both KO and control mice. KO mice displayed increased repetitive behavior in the open field task (clockwise revolutions) and repeated nose pokes, and decreased anxiety in the open field test. No differences in mTOR signaling were found. CONCLUSIONS These findings further illuminate the long-term effects of synergistic impact of two hits on the developing brain.
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Affiliation(s)
- Katherine J Blandin
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
| | - David A Narvaiz
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
| | | | - Paige D Womble
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
| | - Samantha L Hodges
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Matthew S Binder
- Department of Neurosurgery, Yale University School of Medicine, East Haven, CT 06520, USA
| | - Amanda Faust
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
| | - Phuoc H Nguyen
- Department of Neuroscience, University of Maryland, Baltimore, MD 20742, USA
| | | | - Joaquin N Lugo
- Department of Psychology and Neuroscience, Baylor University, Waco, TX 76798, USA
- Department of Biology, Baylor University, Waco, TX 76798, USA
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA
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Valencia ML, Sofela FA, Jongens TA, Sehgal A. Do metabolic deficits contribute to sleep disruption in monogenic intellectual disability syndromes? Trends Neurosci 2024; 47:583-592. [PMID: 39054162 DOI: 10.1016/j.tins.2024.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/28/2024] [Accepted: 06/26/2024] [Indexed: 07/27/2024]
Abstract
Intellectual disability is defined as limitations in cognitive and adaptive behavior that often arise during development. Disordered sleep is common in intellectual disability and, given the importance of sleep for cognitive function, it may contribute to other behavioral phenotypes. Animal models of intellectual disability, in particular of monogenic intellectual disability syndromes (MIDS), recapitulate many disease phenotypes and have been invaluable for linking some of these phenotypes to specific molecular pathways. An emerging feature of MIDS, in both animal models and humans, is the prevalence of metabolic abnormalities, which could be relevant for behavior. Focusing on specific MIDS that have been molecularly characterized, we review sleep, circadian, and metabolic phenotypes in animal models and humans and propose that altered metabolic state contributes to the abnormal sleep/circadian phenotypes in MIDS.
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Affiliation(s)
- Mariela Lopez Valencia
- Chronobiology and Sleep Institute, Perelman Medical School of University of Pennsylvania, Philadelphia, PA, USA
| | - Folasade A Sofela
- Chronobiology and Sleep Institute, Perelman Medical School of University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas A Jongens
- Chronobiology and Sleep Institute, Perelman Medical School of University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Autism Spectrum Program of Excellence, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Amita Sehgal
- Chronobiology and Sleep Institute, Perelman Medical School of University of Pennsylvania, Philadelphia, PA, USA; Howard Hughes Medical Institute, Philadelphia, PA, USA.
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Blum K, Bowirrat A, Sunder K, Thanos PK, Hanna C, Gold MS, Dennen CA, Elman I, Murphy KT, Makale MT. Dopamine Dysregulation in Reward and Autism Spectrum Disorder. Brain Sci 2024; 14:733. [PMID: 39061473 PMCID: PMC11274922 DOI: 10.3390/brainsci14070733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/09/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
Autism spectrum disorder (ASD) is primarily characterized by core deficits in social skills, communication, and cognition and by repetitive stereotyped behaviors. These manifestations are variable between individuals, and ASD pathogenesis is complex, with over a thousand implicated genes, many epigenetic factors, and multiple environmental influences. The mesolimbic dopamine (DA) mediated brain reward system is held to play a key role, but the rapidly expanding literature reveals intricate, nuanced signaling involving a wide array of mesolimbic loci, neurotransmitters and receptor subtypes, and neuronal variants. How altered DA signaling may constitute a downstream convergence of the manifold causal origins of ASD is not well understood. A clear working framework of ASD pathogenesis may help delineate common stages and potential diagnostic and interventional opportunities. Hence, we summarize the known natural history of ASD in the context of emerging data and perspectives to update ASD reward signaling. Then, against this backdrop, we proffer a provisional framework that organizes ASD pathogenesis into successive levels, including (1) genetic and epigenetic changes, (2) disrupted mesolimbic reward signaling pathways, (3) dysregulated neurotransmitter/DA signaling, and finally, (4) altered neurocognitive and social behavior and possible antagonist/agonist based ASD interventions. This subdivision of ASD into a logical progression of potentially addressable parts may help facilitate the rational formulation of diagnostics and targeted treatments.
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Affiliation(s)
- Kenneth Blum
- Division of Addiction Research & Education, Center for Exercise Sports, Mental Health, Western University of Health Sciences, Pomona, CA 91766, USA
- Sunder Foundation, Palm Springs, CA 92264, USA
- Division of Personalized Neuromodulations, PeakLogic, LLC, Del Mar, CA 92130, USA
| | - Abdalla Bowirrat
- Department of Molecular Biology, Adelson School of Medicine, Ariel University, Ariel 40700, Israel
| | | | - Panayotis K. Thanos
- Department of Pharmacology and Toxicology, State University of New York, SUNY, Buffalo, NY 14215, USA
| | - Colin Hanna
- Department of Pharmacology and Toxicology, State University of New York, SUNY, Buffalo, NY 14215, USA
| | - Mark S. Gold
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Catherine A. Dennen
- Department of Family Medicine, Jefferson Health Northeast, Philadelphia, PA 19145, USA
| | - Igor Elman
- Department of Psychiatry, Harvard University School of Medicine, Cambridge, MA 02215, USA
| | - Kevin T. Murphy
- Division of Personalized Neuromodulations, PeakLogic, LLC, Del Mar, CA 92130, USA
| | - Milan T. Makale
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA 92093, USA
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Sudhahar S, Ozer B, Chang J, Chadwick W, O'Donovan D, Campbell A, Tulip E, Thompson N, Roberts I. An experimentally validated approach to automated biological evidence generation in drug discovery using knowledge graphs. Nat Commun 2024; 15:5703. [PMID: 38977662 PMCID: PMC11231212 DOI: 10.1038/s41467-024-50024-6] [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: 05/17/2023] [Accepted: 06/27/2024] [Indexed: 07/10/2024] Open
Abstract
Explaining predictions for drug repositioning with biological knowledge graphs is a challenging problem. Graph completion methods using symbolic reasoning predict drug treatments and associated rules to generate evidence representing the therapeutic basis of the drug. Yet the vast amounts of generated paths that are biologically irrelevant or not mechanistically meaningful within the context of disease biology can limit utility. We use a reinforcement learning based knowledge graph completion model combined with an automatic filtering approach that produces the most relevant rules and biological paths explaining the predicted drug's therapeutic connection to the disease. In this work we validate the approach against preclinical experimental data for Fragile X syndrome demonstrating strong correlation between automatically extracted paths and experimentally derived transcriptional changes of selected genes and pathways of drug predictions Sulindac and Ibudilast. Additionally, we show it reduces the number of generated paths in two case studies, 85% for Cystic fibrosis and 95% for Parkinson's disease.
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Thomson AR, Pasanta D, Arichi T, Puts NA. Neurometabolite differences in Autism as assessed with Magnetic Resonance Spectroscopy: A systematic review and meta-analysis. Neurosci Biobehav Rev 2024; 162:105728. [PMID: 38796123 DOI: 10.1016/j.neubiorev.2024.105728] [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: 01/26/2024] [Revised: 04/23/2024] [Accepted: 05/14/2024] [Indexed: 05/28/2024]
Abstract
1H-Magnetic Resonance Spectroscopy (MRS) is a non-invasive technique that can be used to quantify the concentrations of metabolites in the brain in vivo. MRS findings in the context of autism are inconsistent and conflicting. We performed a systematic review and meta-analysis of MRS studies measuring glutamate and gamma-aminobutyric acid (GABA), as well as brain metabolites involved in energy metabolism (glutamine, creatine), neural and glial integrity (e.g. n-acetyl aspartate (NAA), choline, myo-inositol) and oxidative stress (glutathione) in autism cohorts. Data were extracted and grouped by metabolite, brain region and several other factors before calculation of standardised effect sizes. Overall, we find significantly lower concentrations of GABA and NAA in autism, indicative of disruptions to the balance between excitation/inhibition within brain circuits, as well as neural integrity. Further analysis found these alterations are most pronounced in autistic children and in limbic brain regions relevant to autism phenotypes. Additionally, we show how study outcome varies due to demographic and methodological factors , emphasising the importance of conforming with standardised consensus study designs and transparent reporting.
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Affiliation(s)
- Alice R Thomson
- Department of Forensic and Neurodevelopmental Sciences, King's College London, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, UK; Centre for the Developing Brain, King's College London, London, UK
| | - Duanghathai Pasanta
- Department of Forensic and Neurodevelopmental Sciences, King's College London, UK
| | - Tomoki Arichi
- MRC Centre for Neurodevelopmental Disorders, King's College London, UK; Centre for the Developing Brain, King's College London, London, UK
| | - Nicolaas A Puts
- Department of Forensic and Neurodevelopmental Sciences, King's College London, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, UK.
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Li J, Haj Ebrahimi A, Ali AB. Advances in Therapeutics to Alleviate Cognitive Decline and Neuropsychiatric Symptoms of Alzheimer's Disease. Int J Mol Sci 2024; 25:5169. [PMID: 38791206 PMCID: PMC11121252 DOI: 10.3390/ijms25105169] [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: 04/09/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
Dementia exists as a 'progressive clinical syndrome of deteriorating mental function significant enough to interfere with activities of daily living', with the most prevalent type of dementia being Alzheimer's disease (AD), accounting for about 80% of diagnosed cases. AD is associated with an increased risk of comorbidity with other clinical conditions such as hypertension, diabetes, and neuropsychiatric symptoms (NPS) including, agitation, anxiety, and depression as well as increased mortality in late life. For example, up to 70% of patients diagnosed with AD are affected by anxiety. As aging is the major risk factor for AD, this represents a huge global burden in ageing populations. Over the last 10 years, significant efforts have been made to recognize the complexity of AD and understand the aetiology and pathophysiology of the disease as well as biomarkers for early detection. Yet, earlier treatment options, including acetylcholinesterase inhibitors and glutamate receptor regulators, have been limited as they work by targeting the symptoms, with only the more recent FDA-approved drugs being designed to target amyloid-β protein with the aim of slowing down the progression of the disease. However, these drugs may only help temporarily, cannot stop or reverse the disease, and do not act by reducing NPS associated with AD. The first-line treatment options for the management of NPS are selective serotonin reuptake inhibitors/selective noradrenaline reuptake inhibitors (SSRIs/SNRIs) targeting the monoaminergic system; however, they are not rational drug choices for the management of anxiety disorders since the GABAergic system has a prominent role in their development. Considering the overall treatment failures and side effects of currently available medication, there is an unmet clinical need for rationally designed therapies for anxiety disorders associated with AD. In this review, we summarize the current status of the therapy of AD and aim to highlight novel angles for future drug therapy in our ongoing efforts to alleviate the cognitive deficits and NPS associated with this devastating disease.
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Affiliation(s)
| | | | - Afia B. Ali
- UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK; (J.L.); (A.H.E.)
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Chadwick W, Angulo-Herrera I, Cogram P, Deacon RJM, Mason DJ, Brown D, Roberts I, O’Donovan DJ, Tranfaglia MR, Guilliams T, Thompson NT. A novel combination treatment for fragile X syndrome predicted using computational methods. Brain Commun 2024; 6:fcad353. [PMID: 38226317 PMCID: PMC10789243 DOI: 10.1093/braincomms/fcad353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 11/07/2023] [Accepted: 12/21/2023] [Indexed: 01/17/2024] Open
Abstract
Fragile X syndrome is a neurodevelopmental disorder caused by silencing of the fragile X messenger ribonucleotide gene. Patients display a wide spectrum of symptoms ranging from intellectual and learning disabilities to behavioural challenges including autism spectrum disorder. In addition to this, patients also display a diversity of symptoms due to mosaicism. These factors make fragile X syndrome a difficult syndrome to manage and suggest that a single targeted therapeutic approach cannot address all the symptoms. To this end, we utilized Healx's data-driven drug discovery platform to identify a treatment strategy to address the wide range of diverse symptoms among patients. Computational methods identified the combination of ibudilast and gaboxadol as a treatment for several pathophysiological targets that could potentially reverse multiple symptoms associated with fragile X syndrome. Ibudilast is an approved broad-spectrum phosphodiesterase inhibitor, selective against both phosphodiesterase 4 and phosphodiesterase 10, and has demonstrated to have several beneficial effects in the brain. Gaboxadol is a GABAA receptor agonist, selective against the delta subunit, which has previously displayed encouraging results in a fragile X syndrome clinical trial. Alterations in GABA and cyclic adenosine monophosphate metabolism have long since been associated with the pathophysiology of fragile X syndrome; however, targeting both pathways simultaneously has never been investigated. Both drugs have a good safety and tolerability profile in the clinic making them attractive candidates for repurposing. We set out to explore whether the combination of ibudilast and gaboxadol could demonstrate therapeutic efficacy in a fragile X syndrome mouse model. We found that daily treatment with ibudilast significantly enhanced the ability of fragile X syndrome mice to perform a number of different cognitive assays while gaboxadol treatment improved behaviours such as hyperactivity, aggression, stereotypy and anxiety. Importantly, when ibudilast and gaboxadol were co-administered, the cognitive deficits as well as the aforementioned behaviours were rescued. Moreover, this combination treatment showed no evidence of tolerance, and no adverse effects were reported following chronic dosing. This work demonstrates for the first time that by targeting multiple pathways, with a combination treatment, we were able to rescue more phenotypes in a fragile X syndrome mouse model than either ibudilast or gaboxadol could achieve as monotherapies. This combination treatment approach holds promise for addressing the wide spectrum of diverse symptoms in this heterogeneous patient population and may have therapeutic potential for idiopathic autism.
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Affiliation(s)
| | | | - Patricia Cogram
- Department of Genetics, Faculty of Science, Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago 7800024, Chile
- Center for Neural Circuit Mapping, UCI, School of Medicine, University of California, Irvine, CA 92617, USA
| | - Robert J M Deacon
- Department of Genetics, Faculty of Science, Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago 7800024, Chile
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Quesnel KM, Martin-Kenny N, Bérubé NG. A mouse model of ATRX deficiency with cognitive deficits and autistic traits. J Neurodev Disord 2023; 15:39. [PMID: 37957569 PMCID: PMC10644498 DOI: 10.1186/s11689-023-09508-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND ATRX is an ATP-dependent chromatin remodeling protein with essential roles in safeguarding genome integrity and modulating gene expression. Deficiencies in this protein cause ATR-X syndrome, a condition characterized by intellectual disability and an array of developmental abnormalities, including features of autism. Previous studies demonstrated that deleting ATRX in mouse forebrain excitatory neurons postnatally resulted in male-specific memory deficits, but no apparent autistic-like behaviours. METHODS We generated mice with an earlier embryonic deletion of ATRX in forebrain excitatory neurons and characterized their behaviour using a series of memory and autistic-related paradigms. RESULTS We found that mutant mice displayed a broader spectrum of impairments, including fear memory, decreased anxiety-like behaviour, hyperactivity, as well as self-injurious and repetitive grooming. Sex-specific alterations were also observed, including male-specific aggression, sensory gating impairments, and decreased social memory. CONCLUSIONS Collectively, the findings indicate that early developmental abnormalities arising from ATRX deficiency in forebrain excitatory neurons contribute to the presentation of fear memory deficits as well as autistic-like behaviours.
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Affiliation(s)
- Katherine M Quesnel
- Department of Anatomy & Cell Biology, Western University, London, Canada
- Department of Paediatrics, Western University, London, Canada
- Division of Genetics & Development, Children's Health Research Institute, London, ON, Canada
| | - Nicole Martin-Kenny
- Department of Anatomy & Cell Biology, Western University, London, Canada
- Department of Paediatrics, Western University, London, Canada
- Division of Genetics & Development, Children's Health Research Institute, London, ON, Canada
| | - Nathalie G Bérubé
- Department of Anatomy & Cell Biology, Western University, London, Canada.
- Department of Paediatrics, Western University, London, Canada.
- Division of Genetics & Development, Children's Health Research Institute, London, ON, Canada.
- Department of Oncology, Western University, London, Canada.
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12
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Milla LA, Corral L, Rivera J, Zuñiga N, Pino G, Nunez-Parra A, Cea-Del Rio CA. Neurodevelopment and early pharmacological interventions in Fragile X Syndrome. Front Neurosci 2023; 17:1213410. [PMID: 37599992 PMCID: PMC10433175 DOI: 10.3389/fnins.2023.1213410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Fragile X Syndrome (FXS) is a neurodevelopmental disorder and the leading monogenic cause of autism and intellectual disability. For years, several efforts have been made to develop an effective therapeutic approach to phenotypically rescue patients from the disorder, with some even advancing to late phases of clinical trials. Unfortunately, none of these attempts have completely succeeded, bringing urgency to further expand and refocus research on FXS therapeutics. FXS arises at early stages of postnatal development due to the mutation and transcriptional silencing of the Fragile X Messenger Ribonucleoprotein 1 gene (FMR1) and consequent loss of the Fragile X Messenger Ribonucleoprotein (FMRP) expression. Importantly, FMRP expression is critical for the normal adult nervous system function, particularly during specific windows of embryogenic and early postnatal development. Cellular proliferation, migration, morphology, axonal guidance, synapse formation, and in general, neuronal network establishment and maturation are abnormally regulated in FXS, underlying the cognitive and behavioral phenotypes of the disorder. In this review, we highlight the relevance of therapeutically intervening during critical time points of development, such as early postnatal periods in infants and young children and discuss past and current clinical trials in FXS and their potential to specifically target those periods. We also discuss potential benefits, limitations, and disadvantages of these pharmacological tools based on preclinical and clinical research.
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Affiliation(s)
- Luis A. Milla
- Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Lucia Corral
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Jhanpool Rivera
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Nolberto Zuñiga
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Gabriela Pino
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Alexia Nunez-Parra
- Physiology Laboratory, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile
- Cell Physiology Center, Universidad de Chile, Santiago, Chile
| | - Christian A. Cea-Del Rio
- Laboratorio de Neurofisiopatologia, Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
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13
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Nardi L, Chhabra S, Leukel P, Krueger-Burg D, Sommer CJ, Schmeisser MJ. Neuroanatomical changes of ionotropic glutamatergic and GABAergic receptor densities in male mice modeling idiopathic and syndromic autism spectrum disorder. Front Psychiatry 2023; 14:1199097. [PMID: 37547211 PMCID: PMC10401048 DOI: 10.3389/fpsyt.2023.1199097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/29/2023] [Indexed: 08/08/2023] Open
Abstract
Autism spectrum disorder (ASD) comprises a wide range of neurodevelopment conditions primarily characterized by impaired social interaction and repetitive behavior, accompanied by a variable degree of neuropsychiatric characteristics. Synaptic dysfunction is undertaken as one of the key underlying mechanisms in understanding the pathophysiology of ASD. The excitatory/inhibitory (E/I) hypothesis is one of the most widely held theories for its pathogenesis. Shifts in E/I balance have been proven in several ASD models. In this study, we investigated three mouse lines recapitulating both idiopathic (the BTBR strain) and genetic (Fmr1 and Shank3 mutants) forms of ASD at late infancy and early adulthood. Using receptor autoradiography for ionotropic excitatory (AMPA and NMDA) and inhibitory (GABAA) receptors, we mapped the receptor binding densities in brain regions known to be associated with ASD such as prefrontal cortex, dorsal and ventral striatum, dorsal hippocampus, and cerebellum. The individual mouse lines investigated show specific alterations in excitatory ionotropic receptor density, which might be accounted as specific hallmark of each individual line. Across all the models investigated, we found an increased binding density to GABAA receptors at adulthood in the dorsal hippocampus. Interestingly, reduction in the GABAA receptor binding density was observed in the cerebellum. Altogether, our findings suggest that E/I disbalance individually affects several brain regions in ASD mouse models and that alterations in GABAergic transmission might be accounted as unifying factor.
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Affiliation(s)
- Leonardo Nardi
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Stuti Chhabra
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Petra Leukel
- Institute of Neuropathology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Dilja Krueger-Burg
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Clemens J. Sommer
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
- Institute of Neuropathology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Michael J. Schmeisser
- Institute of Anatomy, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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14
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Abstract
The fragile X-related disorders are an important group of hereditary disorders that are caused by expanded CGG repeats in the 5' untranslated region of the FMR1 gene or by mutations in the coding sequence of this gene. Two categories of pathological CGG repeats are associated with these disorders, full mutation alleles and shorter premutation alleles. Individuals with full mutation alleles develop fragile X syndrome, which causes autism and intellectual disability, whereas those with premutation alleles, which have shorter CGG expansions, can develop fragile X-associated tremor/ataxia syndrome, a progressive neurodegenerative disease. Thus, fragile X-related disorders can manifest as neurodegenerative or neurodevelopmental disorders, depending on the size of the repeat expansion. Here, we review mouse models of fragile X-related disorders and discuss how they have informed our understanding of neurodegenerative and neurodevelopmental disorders. We also assess the translational value of these models for developing rational targeted therapies for intellectual disability and autism disorders.
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Affiliation(s)
- Rob Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
| | - R. Frank Kooy
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
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15
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Cogram P, Fernández-Beltrán LC, Casarejos MJ, Sánchez-Yepes S, Rodríguez-Martín E, García-Rubia A, Sánchez-Barrena MJ, Gil C, Martínez A, Mansilla A. The inhibition of NCS-1 binding to Ric8a rescues fragile X syndrome mice model phenotypes. Front Neurosci 2022; 16:1007531. [PMID: 36466176 PMCID: PMC9709425 DOI: 10.3389/fnins.2022.1007531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 09/26/2022] [Indexed: 01/01/2024] Open
Abstract
Fragile X syndrome (FXS) is caused by the loss of function of Fragile X mental retardation protein (FMRP). FXS is one of the leading monogenic causes of intellectual disability (ID) and autism. Although it is caused by the failure of a single gene, FMRP that functions as an RNA binding protein affects a large number of genes secondarily. All these genes represent hundreds of potential targets and different mechanisms that account for multiple pathological features, thereby hampering the search for effective treatments. In this scenario, it seems desirable to reorient therapies toward more general approaches. Neuronal calcium sensor 1 (NCS-1), through its interaction with the guanine-exchange factor Ric8a, regulates the number of synapses and the probability of the release of a neurotransmitter, the two neuronal features that are altered in FXS and other neurodevelopmental disorders. Inhibitors of the NCS-1/Ric8a complex have been shown to be effective in restoring abnormally high synapse numbers as well as improving associative learning in FMRP mutant flies. Here, we demonstrate that phenothiazine FD44, an NCS-1/Ric8a inhibitor, has strong inhibition ability in situ and sufficient bioavailability in the mouse brain. More importantly, administration of FD44 to two different FXS mouse models restores well-known FXS phenotypes, such as hyperactivity, associative learning, aggressive behavior, stereotype, or impaired social approach. It has been suggested that dopamine (DA) may play a relevant role in the behavior and in neurodevelopmental disorders in general. We have measured DA and its metabolites in different brain regions, finding a higher metabolic rate in the limbic area, which is also restored with FD44 treatment. Therefore, in addition to confirming that the NCS-1/Ric8a complex is an excellent therapeutic target, we demonstrate the rescue effect of its inhibitor on the behavior of cognitive and autistic FXS mice and show DA metabolism as a FXS biochemical disease marker.
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Affiliation(s)
- Patricia Cogram
- Department of Genetics, Institute of Ecology and Biodiversity (IEB), Faculty of Sciences, Universidad de Chile, Santiago, Chile
- FRAXA-DVI, FRAXA Research Foundation, Santiago, Chile
| | - Luis C. Fernández-Beltrán
- Department of Neurobiology, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - María José Casarejos
- Department of Neurobiology, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Sonia Sánchez-Yepes
- Department of Neurobiology, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Eulalia Rodríguez-Martín
- Department of Immunology, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Alfonso García-Rubia
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Carmen Gil
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Madrid, Spain
| | - Ana Martínez
- Centro de Investigaciones Biológicas Margarita Salas-CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Alicia Mansilla
- Department of Neurobiology, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
- Department of Biology Systems, Universidad de Alcala, Madrid, Spain
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16
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The role of the dorsal striatum in a mouse model for fragile X syndrome: Behavioral and dendritic spine assessment. Brain Res 2022; 1795:148060. [PMID: 36030973 DOI: 10.1016/j.brainres.2022.148060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/12/2022] [Accepted: 08/22/2022] [Indexed: 11/23/2022]
Abstract
Fragile X syndrome (FXS), a leading monogenic cause of autism spectrum disorders (ASDs), typically occurs as the result of a mutation silencing the Fmr1 gene, preventing production of the fragile X messenger ribonucleoprotein (FMRP). FXS is characterized, in part, by hyperactivity, impaired behavioral flexibility, and the development of repetitive, or stereotyped, behaviors. While these phenotypes are influenced by striatal activity, few studies have examined FXS or FMRP in the context of striatal function. Here, we report enhanced repetitive behaviors in Fmr1 knockout (KO) compared to wild type (WT) mice according to multiple measures, including quantity and intensity of stereotypic behaviors in an open field and nose poking activity in an unbaited hole board test. However, using a baited version of the hole board assay, we see that KO mice do show some behavioral flexibility in that they make changes in their nose poking behavior following familiarization with an appetitive bait. By contrast, repeated exposure to cocaine (15 mg/kg) promotes repetitive behavior in both WT and KO mice, in a manner mostly independent of genotype. Branch length alterations in medium spiny neurons (MSNs) of the dorsolateral striatum (DLS) are similar between WT cocaine-treated and KO saline-treated mice, possibly suggesting shared synaptic mechanisms. Overall, we suggest that scoring open field behavior is a sensitive measure for repetitive sensory-motor behaviors in Fmr1 KO mice. In addition, our findings show that synaptic contacts onto MSNs in the DLS should be examined in conjunction with measures of stereotypical behavior.
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17
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Zhao H, Mao X, Zhu C, Zou X, Peng F, Yang W, Li B, Li G, Ge T, Cui R. GABAergic System Dysfunction in Autism Spectrum Disorders. Front Cell Dev Biol 2022; 9:781327. [PMID: 35198562 PMCID: PMC8858939 DOI: 10.3389/fcell.2021.781327] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/16/2021] [Indexed: 12/19/2022] Open
Abstract
Autism spectrum disorder (ASD) refers to a series of neurodevelopmental diseases characterized by two hallmark symptoms, social communication deficits and repetitive behaviors. Gamma-aminobutyric acid (GABA) is one of the most important inhibitory neurotransmitters in the central nervous system (CNS). GABAergic inhibitory neurotransmission is critical for the regulation of brain rhythm and spontaneous neuronal activities during neurodevelopment. Genetic evidence has identified some variations of genes associated with the GABA system, indicating an abnormal excitatory/inhibitory (E/I) neurotransmission ratio implicated in the pathogenesis of ASD. However, the specific molecular mechanism by which GABA and GABAergic synaptic transmission affect ASD remains unclear. Transgenic technology enables translating genetic variations into rodent models to further investigate the structural and functional synaptic dysregulation related to ASD. In this review, we summarized evidence from human neuroimaging, postmortem, and genetic and pharmacological studies, and put emphasis on the GABAergic synaptic dysregulation and consequent E/I imbalance. We attempt to illuminate the pathophysiological role of structural and functional synaptic dysregulation in ASD and provide insights for future investigation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ranji Cui
- *Correspondence: Tongtong Ge, ; Ranji Cui,
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18
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van der Lei MB, Kooy RF. Therapeutic potential of GABAA receptor subunit expression abnormalities in fragile X syndrome. EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2022. [DOI: 10.1080/23808993.2021.2008168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - R. Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
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19
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Kurosaki T, Sakano H, Pröschel C, Wheeler J, Hewko A, Maquat LE. NMD abnormalities during brain development in the Fmr1-knockout mouse model of fragile X syndrome. Genome Biol 2021; 22:317. [PMID: 34784943 PMCID: PMC8597091 DOI: 10.1186/s13059-021-02530-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/28/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is an intellectual disability attributable to loss of fragile X protein (FMRP). We previously demonstrated that FMRP binds mRNAs targeted for nonsense-mediated mRNA decay (NMD) and that FMRP loss results in hyperactivated NMD and inhibition of neuronal differentiation in human stem cells. RESULTS We show here that NMD is hyperactivated during the development of the cerebral cortex, hippocampus, and cerebellum in the Fmr1-knockout (KO) mouse during embryonic and early postnatal periods. Our findings demonstrate that NMD regulates many neuronal mRNAs that are important for mouse brain development. CONCLUSIONS We reveal the abnormal regulation of these mRNAs in the Fmr1-KO mouse, a model of FXS, and highlight the importance of early intervention.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
- Center for RNA Biology, University of Rochester, Rochester, NY 14642 USA
| | - Hitomi Sakano
- Center for RNA Biology, University of Rochester, Rochester, NY 14642 USA
- Department of Otolaryngology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
| | - Christoph Pröschel
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
- Stem Cell and Regenerative Medicine Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
| | - Jason Wheeler
- Center for RNA Biology, University of Rochester, Rochester, NY 14642 USA
- Department of Otolaryngology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
| | - Alexander Hewko
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
- Center for RNA Biology, University of Rochester, Rochester, NY 14642 USA
| | - Lynne E. Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642 USA
- Center for RNA Biology, University of Rochester, Rochester, NY 14642 USA
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20
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Hagerman RJ, Hagerman PJ. Fragile X Syndrome: Lessons Learned and What New Treatment Avenues Are on the Horizon. Annu Rev Pharmacol Toxicol 2021; 62:365-381. [PMID: 34499526 DOI: 10.1146/annurev-pharmtox-052120-090147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and the leading single-gene form of autism spectrum disorder, encompassing cognitive, behavioral, and physical forms of clinical involvement. FXS is caused by large expansions of a noncoding CGG repeat (>200 repeats) in the FMR1 gene, at which point the gene is generally silenced. Absence of FMR1 protein (FMRP), important for synaptic development and maintenance, gives rise to the neurodevelopmental disorder. There is, at present, no therapeutic approach that directly reverses the loss of FMRP; however, there is an increasing number of potential treatments that target the pathways dysregulated in FXS, including those that address the enhanced activity of the mGluR5 pathway and deficits in GABA pathways. Based on studies of targeted therapeutics to date, the prospects are good for one or more effective therapies for FXS in the near future. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Randi J Hagerman
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, California 95817, USA; .,MIND Institute, University of California Davis Health, Sacramento, California 95817, USA
| | - Paul J Hagerman
- MIND Institute, University of California Davis Health, Sacramento, California 95817, USA.,Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, California 95616, USA;
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21
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Reyes ST, Deacon RMJ, Guo SG, Altimiras FJ, Castillo JB, van der Wildt B, Morales AP, Park JH, Klamer D, Rosenberg J, Oberman LM, Rebowe N, Sprouse J, Missling CU, McCurdy CR, Cogram P, Kaufmann WE, Chin FT. Effects of the sigma-1 receptor agonist blarcamesine in a murine model of fragile X syndrome: neurobehavioral phenotypes and receptor occupancy. Sci Rep 2021; 11:17150. [PMID: 34433831 PMCID: PMC8387417 DOI: 10.1038/s41598-021-94079-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 06/21/2021] [Indexed: 11/08/2022] Open
Abstract
Fragile X syndrome (FXS), a disorder of synaptic development and function, is the most prevalent genetic form of intellectual disability and autism spectrum disorder. FXS mouse models display clinically-relevant phenotypes, such as increased anxiety and hyperactivity. Despite their availability, so far advances in drug development have not yielded new treatments. Therefore, testing novel drugs that can ameliorate FXS' cognitive and behavioral impairments is imperative. ANAVEX2-73 (blarcamesine) is a sigma-1 receptor (S1R) agonist with a strong safety record and preliminary efficacy evidence in patients with Alzheimer's disease and Rett syndrome, other synaptic neurodegenerative and neurodevelopmental disorders. S1R's role in calcium homeostasis and mitochondrial function, cellular functions related to synaptic function, makes blarcamesine a potential drug candidate for FXS. Administration of blarcamesine in 2-month-old FXS and wild type mice for 2 weeks led to normalization in two key neurobehavioral phenotypes: open field test (hyperactivity) and contextual fear conditioning (associative learning). Furthermore, there was improvement in marble-burying (anxiety, perseverative behavior). It also restored levels of BDNF, a converging point of many synaptic regulators, in the hippocampus. Positron emission tomography (PET) and ex vivo autoradiographic studies, using the highly selective S1R PET ligand [18F]FTC-146, demonstrated the drug's dose-dependent receptor occupancy. Subsequent analyses also showed a wide but variable brain regional distribution of S1Rs, which was preserved in FXS mice. Altogether, these neurobehavioral, biochemical, and imaging data demonstrates doses that yield measurable receptor occupancy are effective for improving the synaptic and behavioral phenotype in FXS mice. The present findings support the viability of S1R as a therapeutic target in FXS, and the clinical potential of blarcamesine in FXS and other neurodevelopmental disorders.
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Affiliation(s)
- Samantha T Reyes
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Robert M J Deacon
- FRAXA-DVI, FRAXA, Santiago, Chile
- IEB, Faculty of Science, University of Chile, Santiago, Chile
- Fraunhofer Chile Research, Center for Systems Biotechnology, Santiago, Chile
| | - Scarlett G Guo
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Francisco J Altimiras
- FRAXA-DVI, FRAXA, Santiago, Chile
- Faculty of Engineering and Business, Universidad de las Américas, Santiago, Chile
| | - Jessa B Castillo
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | | | - Aimara P Morales
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Jun Hyung Park
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Daniel Klamer
- Anavex Life Sciences Corp., New York, NY, 10019, USA
| | - Jarrett Rosenberg
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Lindsay M Oberman
- Center for Neuroscience & Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Nell Rebowe
- Anavex Life Sciences Corp., New York, NY, 10019, USA
| | | | | | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Patricia Cogram
- FRAXA-DVI, FRAXA, Santiago, Chile
- IEB, Faculty of Science, University of Chile, Santiago, Chile
- Fraunhofer Chile Research, Center for Systems Biotechnology, Santiago, Chile
| | - Walter E Kaufmann
- Anavex Life Sciences Corp., New York, NY, 10019, USA.
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| | - Frederick T Chin
- Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
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22
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Rudolph S, Guo C, Pashkovski SL, Osorno T, Gillis WF, Krauss JM, Nyitrai H, Flaquer I, El-Rifai M, Datta SR, Regehr WG. Cerebellum-Specific Deletion of the GABA A Receptor δ Subunit Leads to Sex-Specific Disruption of Behavior. Cell Rep 2021; 33:108338. [PMID: 33147470 PMCID: PMC7700496 DOI: 10.1016/j.celrep.2020.108338] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 08/04/2020] [Accepted: 10/08/2020] [Indexed: 12/19/2022] Open
Abstract
Granule cells (GCs) of the cerebellar input layer express high-affinity δ GABAA subunit-containing GABAA receptors (δGABAARs) that respond to ambient GABA levels and context-dependent neuromodulators like steroids. We find that GC-specific deletion of δGABAA (cerebellar [cb] δ knockout [KO]) decreases tonic inhibition, makes GCs hyperexcitable, and in turn, leads to differential activation of cb output regions as well as many cortical and subcortical brain areas involved in cognition, anxiety-like behaviors, and the stress response. Cb δ KO mice display deficits in many behaviors, but motor function is normal. Strikingly, δGABAA deletion alters maternal behavior as well as spontaneous, stress-related, and social behaviors specifically in females. Our findings establish that δGABAARs enable the cerebellum to control diverse behaviors not previously associated with the cerebellum in a sex-dependent manner. These insights may contribute to a better understanding of the mechanisms that underlie behavioral abnormalities in psychiatric and neurodevelopmental disorders that display a gender bias. Rudolph et al. show that deletion of the neuromodulator and hormone-sensitive δGABAA receptor subunit from cerebellar granule cells results in anxiety-like behaviors and female-specific deficits in social behavior and maternal care. δGABAA deletion is associated with hyperexcitability of the cerebellar input layer and altered activation of many stress-related brain regions.
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Affiliation(s)
- Stephanie Rudolph
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Chong Guo
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stan L Pashkovski
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Tomas Osorno
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Winthrop F Gillis
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeremy M Krauss
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hajnalka Nyitrai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Isabella Flaquer
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Mahmoud El-Rifai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Wade G Regehr
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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23
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Gandhi T, Lee CC. Neural Mechanisms Underlying Repetitive Behaviors in Rodent Models of Autism Spectrum Disorders. Front Cell Neurosci 2021; 14:592710. [PMID: 33519379 PMCID: PMC7840495 DOI: 10.3389/fncel.2020.592710] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) is comprised of several conditions characterized by alterations in social interaction, communication, and repetitive behaviors. Genetic and environmental factors contribute to the heterogeneous development of ASD behaviors. Several rodent models display ASD-like phenotypes, including repetitive behaviors. In this review article, we discuss the potential neural mechanisms involved in repetitive behaviors in rodent models of ASD and related neuropsychiatric disorders. We review signaling pathways, neural circuits, and anatomical alterations in rodent models that display robust stereotypic behaviors. Understanding the mechanisms and circuit alterations underlying repetitive behaviors in rodent models of ASD will inform translational research and provide useful insight into therapeutic strategies for the treatment of repetitive behaviors in ASD and other neuropsychiatric disorders.
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Affiliation(s)
- Tanya Gandhi
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA, United States
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Reyes ST, Mohajeri S, Krasinska K, Guo SG, Gu M, Pisani L, Rosenberg J, Spielman DM, Chin FT. GABA Measurement in a Neonatal Fragile X Syndrome Mouse Model Using 1H-Magnetic Resonance Spectroscopy and Mass Spectrometry. Front Mol Neurosci 2020; 13:612685. [PMID: 33390902 PMCID: PMC7775297 DOI: 10.3389/fnmol.2020.612685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/20/2020] [Indexed: 11/20/2022] Open
Abstract
Fragile X syndrome (FXS) is the leading monogenetic cause of autism spectrum disorder and inherited cause of intellectual disability that affects approximately one in 7,000 males and one in 11,000 females. In FXS, the Fmr1 gene is silenced and prevents the expression of the fragile X mental retardation protein (FMRP) that directly targets mRNA transcripts of multiple GABAA subunits. Therefore, FMRP loss adversely impacts the neuronal firing of the GABAergic system which creates an imbalance in the excitatory/inhibitory ratio within the brain. Current FXS treatment strategies focus on curing symptoms, such as anxiety or decreased social function. While treating symptoms can be helpful, incorporating non-invasive imaging to evaluate how treatments change the brain's biology may explain what molecular aberrations are associated with disease pathology. Thus, the GABAergic system is suitable to explore developing novel therapeutic strategies for FXS. To understand how the GABAergic system may be affected by this loss-of-function mutation, GABA concentrations were examined within the frontal cortex and thalamus of 5-day-old wild type and Fmr1 knockout mice using both 1H magnetic resonance imaging (1H-MRS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Our objective was to develop a reliable scanning method for neonatal mice in vivo and evaluate whether 1H-MRS is suitable to capture regional GABA concentration differences at the front end of the critical cortical period where abnormal neurodevelopment occurs due to FMRP loss is first detected. 1H-MRS quantified GABA concentrations in both frontal cortex and thalamus of wild type and Fmr1 knockout mice. To substantiate the results of our 1H-MRS studies, in vitro LC-MS/MS was also performed on brain homogenates from age-matched mice. We found significant changes in GABA concentration between the frontal cortex and thalamus within each mouse from both wild type and Fmr1 knockout mice using 1H-MRS and LC-MS/MS. Significant GABA levels were also detected in these same regions between wild type and Fmr1 knockout mice by LC-MS/MS, validating that FMRP loss directly affects the GABAergic system. Thus, these new findings support the need to develop an effective non-invasive imaging method to monitor novel GABAergic strategies aimed at treating patients with FXS.
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Affiliation(s)
- Samantha T. Reyes
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Sanaz Mohajeri
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Karolina Krasinska
- Stanford University Mass Spectrometry Laboratory, Stanford University, Stanford, CA, United States
| | - Scarlett G. Guo
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Meng Gu
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Laura Pisani
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Jarrett Rosenberg
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Daniel M. Spielman
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Frederick T. Chin
- Department of Radiology, Stanford University, Stanford, CA, United States
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25
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Menduti G, Rasà DM, Stanga S, Boido M. Drug Screening and Drug Repositioning as Promising Therapeutic Approaches for Spinal Muscular Atrophy Treatment. Front Pharmacol 2020; 11:592234. [PMID: 33281605 PMCID: PMC7689316 DOI: 10.3389/fphar.2020.592234] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/29/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the most common genetic disease affecting infants and young adults. Due to mutation/deletion of the survival motor neuron (SMN) gene, SMA is characterized by the SMN protein lack, resulting in motor neuron impairment, skeletal muscle atrophy and premature death. Even if the genetic causes of SMA are well known, many aspects of its pathogenesis remain unclear and only three drugs have been recently approved by the Food and Drug Administration (Nusinersen-Spinraza; Onasemnogene abeparvovec or AVXS-101-Zolgensma; Risdiplam-Evrysdi): although assuring remarkable results, the therapies show some important limits including high costs, still unknown long-term effects, side effects and disregarding of SMN-independent targets. Therefore, the research of new therapeutic strategies is still a hot topic in the SMA field and many efforts are spent in drug discovery. In this review, we describe two promising strategies to select effective molecules: drug screening (DS) and drug repositioning (DR). By using compounds libraries of chemical/natural compounds and/or Food and Drug Administration-approved substances, DS aims at identifying new potentially effective compounds, whereas DR at testing drugs originally designed for the treatment of other pathologies. The drastic reduction in risks, costs and time expenditure assured by these strategies make them particularly interesting, especially for those diseases for which the canonical drug discovery process would be long and expensive. Interestingly, among the identified molecules by DS/DR in the context of SMA, besides the modulators of SMN2 transcription, we highlighted a convergence of some targeted molecular cascades contributing to SMA pathology, including cell death related-pathways, mitochondria and cytoskeleton dynamics, neurotransmitter and hormone modulation.
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Affiliation(s)
| | | | | | - Marina Boido
- Department of Neuroscience Rita Levi Montalcini, Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Turin, Italy
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26
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Falk-Petersen CB, Tsonkov TM, Nielsen MS, Harpsøe K, Bundgaard C, Frølund B, Kristiansen U, Gloriam DE, Wellendorph P. Discovery of a new class of orthosteric antagonists with nanomolar potency at extrasynaptic GABA A receptors. Sci Rep 2020; 10:10078. [PMID: 32572053 PMCID: PMC7308271 DOI: 10.1038/s41598-020-66821-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Brain GABAΑ receptors are ionotropic receptors belonging to the class of Cys-loop receptors and are important drug targets for the treatment of anxiety and sleep disorders. By screening a compound library (2,112 compounds) at recombinant human α4β1δ GABAΑ receptors heterologously expressed in a HEK cell line, we identified a scaffold of spirocyclic compounds with nanomolar antagonist activity at GABAΑ receptors. The initial screening hit 2027 (IC50 of 1.03 μM) was used for analogue search resulting in 018 (IC50 of 0.088 μM). 018 was most potent at α3,4,5-subunit containing receptors, thus showing preference for forebrain-expressed extrasynaptic receptors. Schild analysis of 018 at recombinant human α4β1δ receptors and displacement of [3H]muscimol binding in rat cortical homogenate independently confirmed a competitive profile. The antagonist profile of 018 was further validated by whole-cell patch-clamp electrophysiology, where kinetic studies revealed a slow dissociation rate and a shallow hill slope was observed. Membrane permeability studies showed that 2027 and 018 do not cross membranes, thus making the compounds less attractive for studying central GABAΑ receptors effects, but conversely more attractive as tool compounds in relation to emerging peripheral GABAΑ receptor-mediated effects of GABA e.g. in the immune system.
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Affiliation(s)
- Christina Birkedahl Falk-Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Tsonko M Tsonkov
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Malene Sofie Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Kasper Harpsøe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | | | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Uffe Kristiansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - David E Gloriam
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark.
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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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28
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Shitik EM, Velmiskina AA, Dolskiy AA, Yudkin DV. Reactivation of FMR1 gene expression is a promising strategy for fragile X syndrome therapy. Gene Ther 2020; 27:247-253. [PMID: 32203197 DOI: 10.1038/s41434-020-0141-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 02/06/2023]
Abstract
Fragile X syndrome (FXS) is the most common form of intellectual disability and autism spectrum disorder and is caused by CGG repeat expansion in the promoter region of the FMR1 gene, which encodes fragile X mental retardation protein. This event leads to gene silencing and the loss of gene products through DNA methylation and chromatin remodeling. Due to the pathogenesis of FXS, targeted, symptomatic, and etiological approaches have been developed for its treatment. Despite their rapid development, symptomatic and targeted treatment approaches have numerous limitations; etiological approaches have the greatest potential because they affect the main causes of transcriptional silencing. In this review, we consider three potential etiological therapeutic methods that affect the reactivation of FMR1 gene expression: treatment with inhibitors of chromatin-modifying enzymes, the use of noncoding RNAs and the application of gene therapy. Inhibitors of chromatin-modifying enzymes are not clinically applicable because of their low reactivity and high cytotoxicity, and noncoding RNAs are currently only under study. Thus, we discuss gene therapy as the most promising approach for treating FXS in the near future.
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Affiliation(s)
- Ekaterina M Shitik
- State Research Center of Virology and Biotechnology "Vector", Federal Service for Surveillance on Consumer Rights Protection and Human Well-being (FBRI SRC VB "Vector", Rospotrebnadzor), Koltsovo, Novosibirsk Region, Russia
| | - Anastasia A Velmiskina
- State Research Center of Virology and Biotechnology "Vector", Federal Service for Surveillance on Consumer Rights Protection and Human Well-being (FBRI SRC VB "Vector", Rospotrebnadzor), Koltsovo, Novosibirsk Region, Russia
| | - Alexander A Dolskiy
- State Research Center of Virology and Biotechnology "Vector", Federal Service for Surveillance on Consumer Rights Protection and Human Well-being (FBRI SRC VB "Vector", Rospotrebnadzor), Koltsovo, Novosibirsk Region, Russia
| | - Dmitry V Yudkin
- State Research Center of Virology and Biotechnology "Vector", Federal Service for Surveillance on Consumer Rights Protection and Human Well-being (FBRI SRC VB "Vector", Rospotrebnadzor), Koltsovo, Novosibirsk Region, Russia.
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Van der Aa N, Kooy RF. GABAergic abnormalities in the fragile X syndrome. Eur J Paediatr Neurol 2020; 24:100-104. [PMID: 31926845 DOI: 10.1016/j.ejpn.2019.12.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/18/2019] [Indexed: 12/24/2022]
Abstract
Many pathways have been involved in pathophysiology of the fragile X syndrome, one of the more frequent genetic causes of intellectual disability and autism. This review highlights the recent insights in the role the abnormalities in the GABAergic system play in the disorder. Since the initial observations showed that the expression of specific subunits of the GABA(A) receptor were underexpressed in the fragile X knockout mouse model more than a decade ago, evidence has accumulated that the expression of approximately half of the GABAergic system is compromised in multiple species, including in fragile X patients. Functional consequences of the GABAergic deficiencies could be measured using whole-cell voltage clamp recordings. Pharmalogical treatment with agonist of the receptor was been able to restore several behavioral deficits in the fragile X mouse model, including seizures, marble burying and, in part, prepulse inhibition. Trials in patients with the same agonist have demonstrated encouraging post-hoc results in the most severely affected patients, although no effect could be demonstrated in the patient group as a whole. In conclusion, there can be little doubt that the GABAergic system is compromised in the fragile X syndrome and that these abnormalities contribute to the clinical abnormalities observed. However, at the moment the difference in treatment effectiveness of agonist of the receptor in animal models as opposed to in patients remains unexplained.
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Affiliation(s)
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
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