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Bovio PP, Franz H, Heidrich S, Rauleac T, Kilpert F, Manke T, Vogel T. Differential Methylation of H3K79 Reveals DOT1L Target Genes and Function in the Cerebellum In Vivo. Mol Neurobiol 2018; 56:4273-4287. [PMID: 30302725 PMCID: PMC6505521 DOI: 10.1007/s12035-018-1377-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 10/01/2018] [Indexed: 12/21/2022]
Abstract
The disruptor of telomeric silencing 1-like (DOT1L) mediates methylation of histone H3 at position lysine 79 (H3K79). Conditional knockout of Dot1l in mouse cerebellar granule cells (Dot1l-cKOAtoh1) led to a smaller external granular layer with fewer precursors of granule neurons. Dot1l-cKOAtoh1 mice had impaired proliferation and differentiation of granular progenitors, which resulted in a smaller cerebellum. Mutant mice showed mild ataxia in motor behavior tests. In contrast, Purkinje cell-specific conditional knockout mice showed no obvious phenotype. Genome-wide transcription analysis of Dot1l-cKOAtoh1 cerebella using microarrays revealed changes in genes that function in cell cycle, cell migration, axon guidance, and metabolism. To identify direct DOT1L target genes, we used genome-wide profiling of H3K79me2 and transcriptional analysis. Analysis of differentially methylated regions (DR) and differentially expressed genes (DE) revealed in total 12 putative DOT1L target genes in Dot1l-cKOAtoh1 affecting signaling (Tnfaip8l3, B3galt5), transcription (Otx1), cell migration and axon guidance (Sema4a, Sema5a, Robo1), cholesterol and lipid metabolism (Lss, Cyp51), cell cycle (Cdkn1a), calcium-dependent cell-adhesion or exocytosis (Pcdh17, Cadps2), and unknown function (Fam174b). Dysregulated expression of these target genes might be implicated in the ataxia phenotype observed in Dot1l-cKOAtoh1.
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Affiliation(s)
- Patrick Piero Bovio
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Henriette Franz
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany
| | - Stefanie Heidrich
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany
| | - Tudor Rauleac
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany
| | - Fabian Kilpert
- Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Thomas Manke
- Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Tanja Vogel
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany.
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Adult Ube3a Gene Reinstatement Restores the Electrophysiological Deficits of Prefrontal Cortex Layer 5 Neurons in a Mouse Model of Angelman Syndrome. J Neurosci 2018; 38:8011-8030. [PMID: 30082419 DOI: 10.1523/jneurosci.0083-18.2018] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 07/13/2018] [Accepted: 07/20/2018] [Indexed: 11/21/2022] Open
Abstract
E3 ubiquitin ligase (UBE3A) levels in the brain need to be tightly regulated, as loss of functional UBE3A protein is responsible for the severe neurodevelopmental disorder Angelman syndrome (AS), whereas increased activity of UBE3A is associated with nonsyndromic autism. Given the role of mPFC in neurodevelopmental disorders including autism, we aimed to identify the functional changes resulting from loss of UBE3A in infralimbic and prelimbic mPFC areas in a mouse model of AS. Whole-cell recordings from layer 5 mPFC pyramidal neurons obtained in brain slices from adult mice of both sexes revealed that loss of UBE3A results in a strong decrease of spontaneous inhibitory transmission and increase of spontaneous excitatory transmission potentially leading to a marked excitation/inhibition imbalance. Additionally, we found that loss of UBE3A led to decreased excitability and increased threshold for action potential of layer 5 fast spiking interneurons without significantly affecting the excitability of pyramidal neurons. Because we previously showed that AS mouse behavioral phenotypes are reversible upon Ube3a gene reactivation during a restricted period of early postnatal development, we investigated whether Ube3a gene reactivation in a fully mature brain could reverse any of the identified physiological deficits. In contrast to our previously reported behavioral findings, restoring UBE3A levels in adult animals fully rescued all the identified physiological deficits of mPFC neurons. Moreover, the kinetics of reversing these synaptic deficits closely followed the reinstatement of UBE3A protein level. Together, these findings show a striking dissociation between the rescue of behavioral and physiological deficits.SIGNIFICANCE STATEMENT Here we describe significant physiological deficits in the mPFC of an Angelman syndrome mouse model. We found a marked change in excitatory/inhibitory balance, as well as decreased excitability of fast spiking interneurons. A promising treatment strategy for Angelman syndrome is aimed at restoring UBE3A expression by activating the paternal UBE3A gene. Here we find that the physiological changes in the mPFC are fully reversible upon gene reactivation, even when the brain is fully mature. This indicates that there is no critical developmental window for reversing the identified physiological deficits in mPFC.
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Grieco JC, Gouelle A, Weeber EJ. Identification of spatiotemporal gait parameters and pressure-related characteristics in children with Angelman syndrome: A pilot study. JOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES 2018; 31:1219-1224. [PMID: 29737626 DOI: 10.1111/jar.12462] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND Angelman syndrome (AS) leads to clinical manifestations that include intellectual impairments, developmental delay and poor motor function. Initiatives to develop therapeutics implie an urgent need to identify methods that accurately measure the motor abilities. METHODS Six children with AS (6 to 9 years old) walked on an instrumented walkway to get spatiotemporal parameters (STPs) and center of pressure (CoP). These outcomes were compared to typically developing children (TD): 44 TD 6 to 9 years old and 20 TD 4 to 5 years old. RESULTS Analysis revealed differences in all STPs and gait variability index when compared to TD individuals. When AS participants were compared to younger TD individuals, except step length, STPs were different. Analysis of the CoP pathway revealed a less consistent and efficient pathway in AS. CONCLUSIONS We could delineate the functional difference between children with AS and TD children. The variability of STP and the CoP were the most valuable components in gait to be considered in AS.
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Affiliation(s)
- Joseph C Grieco
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Arnaud Gouelle
- Gait & Balance Academy, ProtoKinetics, Gometz-le-Châtel, France.,UFR STAPS de Reims, Laboratoire Performance, Santé, Métrologie, Société (PSMS, EA 7507), Reims, France
| | - Edwin J Weeber
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
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Ali Rodriguez R, Joya C, Hines RM. Common Ribs of Inhibitory Synaptic Dysfunction in the Umbrella of Neurodevelopmental Disorders. Front Mol Neurosci 2018; 11:132. [PMID: 29740280 PMCID: PMC5928253 DOI: 10.3389/fnmol.2018.00132] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/03/2018] [Indexed: 01/06/2023] Open
Abstract
The term neurodevelopmental disorder (NDD) is an umbrella term used to group together a heterogeneous class of disorders characterized by disruption in cognition, emotion, and behavior, early in the developmental timescale. These disorders are heterogeneous, yet they share common behavioral symptomatology as well as overlapping genetic contributors, including proteins involved in the formation, specialization, and function of synaptic connections. Advances may arise from bridging the current knowledge on synapse related factors indicated from both human studies in NDD populations, and in animal models. Mounting evidence has shown a link to inhibitory synapse formation, specialization, and function among Autism, Angelman, Rett and Dravet syndromes. Inhibitory signaling is diverse, with numerous subtypes of inhibitory interneurons, phasic and tonic modes of inhibition, and the molecular and subcellular diversity of GABAA receptors. We discuss common ribs of inhibitory synapse dysfunction in the umbrella of NDD, highlighting alterations in the developmental switch to inhibitory GABA, dysregulation of neuronal activity patterns by parvalbumin-positive interneurons, and impaired tonic inhibition. Increasing our basic understanding of inhibitory synapses, and their role in NDDs is likely to produce significant therapeutic advances in behavioral symptom alleviation for interrelated NDDs.
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Affiliation(s)
- Rachel Ali Rodriguez
- Neuroscience Emphasis, Department of Psychology, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Christina Joya
- Neuroscience Emphasis, Department of Psychology, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Rochelle M Hines
- Neuroscience Emphasis, Department of Psychology, University of Nevada, Las Vegas, Las Vegas, NV, United States
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55
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Control of motor coordination by astrocytic tonic GABA release through modulation of excitation/inhibition balance in cerebellum. Proc Natl Acad Sci U S A 2018; 115:5004-5009. [PMID: 29691318 DOI: 10.1073/pnas.1721187115] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tonic inhibition in the brain is mediated through an activation of extrasynaptic GABAA receptors by the tonically released GABA, resulting in a persistent GABAergic inhibitory action. It is one of the key regulators for neuronal excitability, exerting a powerful action on excitation/inhibition balance. We have previously reported that astrocytic GABA, synthesized by monoamine oxidase B (MAOB), mediates tonic inhibition via GABA-permeable bestrophin 1 (Best1) channel in the cerebellum. However, the role of astrocytic GABA in regulating neuronal excitability, synaptic transmission, and cerebellar brain function has remained elusive. Here, we report that a reduction of tonic GABA release by genetic removal or pharmacological inhibition of Best1 or MAOB caused an enhanced neuronal excitability in cerebellar granule cells (GCs), synaptic transmission at the parallel fiber-Purkinje cell (PF-PC) synapses, and motor performance on the rotarod test, whereas an augmentation of tonic GABA release by astrocyte-specific overexpression of MAOB resulted in a reduced neuronal excitability, synaptic transmission, and motor performance. The bidirectional modulation of astrocytic GABA by genetic alteration of Best1 or MAOB was confirmed by immunostaining and in vivo microdialysis. These findings indicate that astrocytes are the key player in motor coordination through tonic GABA release by modulating neuronal excitability and could be a good therapeutic target for various movement and psychiatric disorders, which show a disturbed excitation/inhibition balance.
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56
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Guzzetti S, Calzari L, Buccarello L, Cesari V, Toschi I, Cattaldo S, Mauro A, Pregnolato F, Mazzola SM, Russo S. Taurine Administration Recovers Motor and Learning Deficits in an Angelman Syndrome Mouse Model. Int J Mol Sci 2018; 19:ijms19041088. [PMID: 29621152 PMCID: PMC5979575 DOI: 10.3390/ijms19041088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 03/30/2018] [Accepted: 03/30/2018] [Indexed: 12/13/2022] Open
Abstract
Angelman syndrome (AS, MIM 105830) is a rare neurodevelopmental disorder affecting 1:10–20,000 children. Patients show moderate to severe intellectual disability, ataxia and absence of speech. Studies on both post-mortem AS human brains and mouse models revealed dysfunctions in the extra synaptic gamma-aminobutyric acid (GABA) receptors implicated in the pathogenesis. Taurine is a free intracellular sulfur-containing amino acid, abundant in brain, considered an inhibiting neurotransmitter with neuroprotective properties. As taurine acts as an agonist of GABA-A receptors, we aimed at investigating whether it might ameliorate AS symptoms. Since mice weaning, we orally administered 1 g/kg/day taurine in water to Ube3a-deficient mice. To test the improvement of motor and cognitive skills, Rotarod, Novel Object Recognition and Open Field tests were assayed at 7, 14, 21 and 30 weeks, while biochemical tests and amino acid dosages were carried out, respectively, by Western-blot and high-performance liquid chromatography (HPLC) on frozen whole brains. Treatment of Ube3am−/p+ mice with taurine significantly improved motor and learning skills and restored the levels of the post-synaptic PSD-95 and pERK1/2-ERK1/2 ratio to wild type values. No side effects of taurine were observed. Our study indicates taurine administration as a potential therapy to ameliorate motor deficits and learning difficulties in AS.
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Affiliation(s)
- Sara Guzzetti
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, IRCCS, 20145 Milano, Italy.
| | - Luciano Calzari
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, IRCCS, 20145 Milano, Italy.
| | - Lucia Buccarello
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, IRCCS, 20145 Milano, Italy.
| | - Valentina Cesari
- Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, 20133 Milano, Italy.
| | - Ivan Toschi
- Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, 20133 Milano, Italy.
| | - Stefania Cattaldo
- Laboratory of Clinical Neurobiology, Istituto Auxologico Italiano, IRCCS, 28824 Piancavallo-Verbania, Italy.
| | - Alessandro Mauro
- Laboratory of Clinical Neurobiology, Istituto Auxologico Italiano, IRCCS, 28824 Piancavallo-Verbania, Italy.
- Division of Neurology and Neurorehabilitation, Istituto Auxologico Italiano, IRCCS, 28824 Piancavallo-Verbania, Italy.
- Department of Neurosciences, Università di Torino, 10126 Torino, Italy.
| | - Francesca Pregnolato
- Experimental Laboratory of Immunological and Rheumatologic Researches, Istituto Auxologico Italiano, IRCCS, 20145 Milano, Italy.
| | - Silvia Michela Mazzola
- Department of Veterinary Medicine, Università degli Studi di Milano, 20133 Milano, Italy.
| | - Silvia Russo
- Cytogenetics and Molecular Genetics Laboratory, Istituto Auxologico Italiano, IRCCS, 20145 Milano, Italy.
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58
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Murakami G, Edamura M, Furukawa T, Kawasaki H, Kosugi I, Fukuda A, Iwashita T, Nakahara D. MHC class I in dopaminergic neurons suppresses relapse to reward seeking. SCIENCE ADVANCES 2018; 4:eaap7388. [PMID: 29546241 PMCID: PMC5851664 DOI: 10.1126/sciadv.aap7388] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 02/07/2018] [Indexed: 05/12/2023]
Abstract
Major histocompatibility complex class I (MHCI) is an important immune protein that is expressed in various brain regions, with its deficiency leading to extensive synaptic transmission that results in learning and memory deficits. Although MHCI is highly expressed in dopaminergic neurons, its role in these neurons has not been examined. We show that MHCI expressed in dopaminergic neurons plays a key role in suppressing reward-seeking behavior. In wild-type mice, cocaine self-administration caused persistent reduction of MHCI specifically in dopaminergic neurons, which was accompanied by enhanced glutamatergic synaptic transmission and relapse to cocaine seeking. Functional MHCI knockout promoted this addictive phenotype for cocaine and a natural reward, namely, sucrose. In contrast, wild-type mice overexpressing a major MHCI gene (H2D) in dopaminergic neurons showed suppressed cocaine seeking. These results show that persistent cocaine-induced reduction of MHCI in dopaminergic neurons is necessary for relapse to cocaine seeking.
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Affiliation(s)
- Gen Murakami
- Department of Psychology and Behavioral Neuroscience, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
- Department of Regenerative and Infectious Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
- Department of Liberal Arts, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan
| | - Mitsuhiro Edamura
- Department of Psychology and Behavioral Neuroscience, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Tomonori Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Hideya Kawasaki
- Department of Regenerative and Infectious Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Isao Kosugi
- Department of Regenerative and Infectious Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Toshihide Iwashita
- Department of Regenerative and Infectious Pathology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Daiichiro Nakahara
- Department of Psychology and Behavioral Neuroscience, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
- Department of Psychiatry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
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59
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Cheon S, Dean M, Chahrour M. The ubiquitin proteasome pathway in neuropsychiatric disorders. Neurobiol Learn Mem 2018; 165:106791. [PMID: 29398581 DOI: 10.1016/j.nlm.2018.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/19/2018] [Accepted: 01/26/2018] [Indexed: 12/20/2022]
Abstract
The ubiquitin proteasome system (UPS) is a highly conserved pathway that tightly regulates protein turnover in cells. This process is integral to neuronal development, differentiation, and function. Several members of the UPS are disrupted in neuropsychiatric disorders, highlighting the importance of this pathway in brain development and function. In this review, we discuss some of these pathway members, the molecular processes they regulate, and the potential for targeting the UPS in an effort to develop therapeutic strategies in neuropsychiatric and neurodevelopmental disorders.
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Affiliation(s)
- Solmi Cheon
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Milan Dean
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maria Chahrour
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Departments of Neuroscience and Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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60
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Takahashi Y, Wu J, Suzuki K, Martinez-Redondo P, Li M, Liao HK, Wu MZ, Hernández-Benítez R, Hishida T, Shokhirev MN, Esteban CR, Sancho-Martinez I, Belmonte JCI. Integration of CpG-free DNA induces de novo methylation of CpG islands in pluripotent stem cells. Science 2018; 356:503-508. [PMID: 28473583 DOI: 10.1126/science.aag3260] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 12/12/2016] [Accepted: 04/06/2017] [Indexed: 12/31/2022]
Abstract
CpG islands (CGIs) are primarily promoter-associated genomic regions and are mostly unmethylated within highly methylated mammalian genomes. The mechanisms by which CGIs are protected from de novo methylation remain elusive. Here we show that insertion of CpG-free DNA into targeted CGIs induces de novo methylation of the entire CGI in human pluripotent stem cells (PSCs). The methylation status is stably maintained even after CpG-free DNA removal, extensive passaging, and differentiation. By targeting the DNA mismatch repair gene MLH1 CGI, we could generate a PSC model of a cancer-related epimutation. Furthermore, we successfully corrected aberrant imprinting in induced PSCs derived from an Angelman syndrome patient. Our results provide insights into how CpG-free DNA induces de novo CGI methylation and broaden the application of targeted epigenome editing for a better understanding of human development and disease.
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Affiliation(s)
- Yuta Takahashi
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.,Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Jun Wu
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.,Universidad Católica San Antonio de Murcia (UCAM) Campus de los Jerónimos, N° 135 Guadalupe 30107, Murcia, Spain
| | - Keiichiro Suzuki
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Paloma Martinez-Redondo
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Mo Li
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.,King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Hsin-Kai Liao
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Min-Zu Wu
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.,Universidad Católica San Antonio de Murcia (UCAM) Campus de los Jerónimos, N° 135 Guadalupe 30107, Murcia, Spain
| | - Reyna Hernández-Benítez
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.,King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Tomoaki Hishida
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Maxim Nikolaievich Shokhirev
- Integrative Genomics and Bioinformatics Core, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Concepcion Rodriguez Esteban
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ignacio Sancho-Martinez
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Juan Carlos Izpisua Belmonte
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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61
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Bozzi Y, Provenzano G, Casarosa S. Neurobiological bases of autism-epilepsy comorbidity: a focus on excitation/inhibition imbalance. Eur J Neurosci 2017; 47:534-548. [PMID: 28452083 DOI: 10.1111/ejn.13595] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/18/2017] [Accepted: 04/21/2017] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorders (ASD) and epilepsy are common neurological diseases of childhood, with an estimated incidence of approximately 0.5-1% of the worldwide population. Several genetic, neuroimaging and neuropathological studies clearly showed that both ASD and epilepsy have developmental origins and a substantial degree of heritability. Most importantly, ASD and epilepsy frequently coexist in the same individual, suggesting a common neurodevelopmental basis for these disorders. Genome-wide association studies recently allowed for the identification of a substantial number of genes involved in ASD and epilepsy, some of which are mutated in syndromes presenting both ASD and epilepsy clinical features. At the cellular level, both preclinical and clinical studies indicate that the different genetic causes of ASD and epilepsy may converge to perturb the excitation/inhibition (E/I) balance, due to the dysfunction of excitatory and inhibitory circuits in various brain regions. Metabolic and immune dysfunctions, as well as environmental causes also contribute to ASD pathogenesis. Thus, an E/I imbalance resulting from neurodevelopmental deficits of multiple origins might represent a common pathogenic mechanism for both diseases. Here, we will review the most significant studies supporting these hypotheses. A deeper understanding of the molecular and cellular determinants of autism-epilepsy comorbidity will pave the way to the development of novel therapeutic strategies.
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Affiliation(s)
- Yuri Bozzi
- Neurodevelopmental Disorders Research Group, Centre for Mind/Brain Sciences, University of Trento, via Sommarive 9, 38123, Povo, Trento, Italy.,CNR Neuroscience Institute, Pisa, Italy
| | - Giovanni Provenzano
- Laboratory of Molecular Neuropathology, Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Simona Casarosa
- CNR Neuroscience Institute, Pisa, Italy.,Laboratory of Neural Development and Regeneration, Centre for Integrative Biology, University of Trento, Trento, Italy
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62
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Lee E, Lee J, Kim E. Excitation/Inhibition Imbalance in Animal Models of Autism Spectrum Disorders. Biol Psychiatry 2017; 81:838-847. [PMID: 27450033 DOI: 10.1016/j.biopsych.2016.05.011] [Citation(s) in RCA: 291] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/02/2016] [Accepted: 05/16/2016] [Indexed: 12/19/2022]
Abstract
Imbalances between excitation and inhibition in synaptic transmission and neural circuits have been implicated in autism spectrum disorders. Excitation and inhibition imbalances are frequently observed in animal models of autism spectrum disorders, and their correction normalizes key autistic-like phenotypes in these animals. These results suggest that excitation and inhibition imbalances may contribute to the development and maintenance of autism spectrum disorders and represent an important therapeutic target.
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Affiliation(s)
- Eunee Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea
| | - Jiseok Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Korea; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
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63
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Sidorov MS, Deck GM, Dolatshahi M, Thibert RL, Bird LM, Chu CJ, Philpot BD. Delta rhythmicity is a reliable EEG biomarker in Angelman syndrome: a parallel mouse and human analysis. J Neurodev Disord 2017; 9:17. [PMID: 28503211 PMCID: PMC5422949 DOI: 10.1186/s11689-017-9195-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/21/2017] [Indexed: 01/11/2023] Open
Abstract
Background Clinicians have qualitatively described rhythmic delta activity as a prominent EEG abnormality in individuals with Angelman syndrome, but this phenotype has yet to be rigorously quantified in the clinical population or validated in a preclinical model. Here, we sought to quantitatively measure delta rhythmicity and evaluate its fidelity as a biomarker. Methods We quantified delta oscillations in mouse and human using parallel spectral analysis methods and measured regional, state-specific, and developmental changes in delta rhythms in a patient population. Results Delta power was broadly increased and more dynamic in both the Angelman syndrome mouse model, relative to wild-type littermates, and in children with Angelman syndrome, relative to age-matched neurotypical controls. Enhanced delta oscillations in children with Angelman syndrome were present during wakefulness and sleep, were generalized across the neocortex, and were more pronounced at earlier ages. Conclusions Delta rhythmicity phenotypes can serve as reliable biomarkers for Angelman syndrome in both preclinical and clinical settings. Electronic supplementary material The online version of this article (doi:10.1186/s11689-017-9195-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael S Sidorov
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599 USA.,Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599 USA.,Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599 USA
| | - Gina M Deck
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114 USA.,Harvard Medical School, Boston, MA 02215 USA.,Present Address: The Neurology Foundation, Rhode Island Hospital and Warren Alpert School of Medicine at Brown University, Providence, RI 02903 USA
| | - Marjan Dolatshahi
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114 USA.,Harvard Medical School, Boston, MA 02215 USA
| | - Ronald L Thibert
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Lynne M Bird
- Department of Pediatrics, University of California, San Diego, CA USA.,Division of Dysmorphology/Genetics, Rady Children's Hospital, San Diego, CA USA
| | - Catherine J Chu
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114 USA.,Harvard Medical School, Boston, MA 02215 USA
| | - Benjamin D Philpot
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599 USA.,Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599 USA.,Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599 USA
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Peter S, De Zeeuw CI, Boeckers TM, Schmeisser MJ. Cerebellar and Striatal Pathologies in Mouse Models of Autism Spectrum Disorder. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2017; 224:103-119. [PMID: 28551753 DOI: 10.1007/978-3-319-52498-6_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with a strong genetic component. To date, several hundred different genetic mutations have been identified to play a role in its aetiology. The heterogeneity of genetic abnormalities combined with the different brain regions where aberrations are found makes the search for causative mechanisms a daunting task. Even within a limited number of brain regions, a myriad of different neural circuit dysfunctions may lead to ASD. Here, we review mouse models that incorporate mutations of ASD risk genes causing pathologies in the cerebellum and striatum and highlight the vulnerability of related circuit dysfunctions within these brain regions in ASD pathophysiology.
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Affiliation(s)
- Saša Peter
- Netherlands Institute for Neuroscience, Amsterdam, The Netherlands. .,Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
| | - Chris I De Zeeuw
- Netherlands Institute for Neuroscience, Amsterdam, The Netherlands.,Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Michael J Schmeisser
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany. .,Division of Neuroanatomy, Institute of Anatomy, Otto-von-Guericke University, Magdeburg, Germany. .,Leibniz Institute for Neurobiology, Magdeburg, Germany.
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65
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Ciarlone SL, Wang X, Rogawski MA, Weeber EJ. Effects of the synthetic neurosteroid ganaxolone on seizure activity and behavioral deficits in an Angelman syndrome mouse model. Neuropharmacology 2016; 116:142-150. [PMID: 27986596 DOI: 10.1016/j.neuropharm.2016.12.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/02/2016] [Accepted: 12/12/2016] [Indexed: 11/25/2022]
Abstract
Angelman syndrome (AS) is a rare neurogenetic disorder characterized by severe developmental delay, motor impairments, and epilepsy. GABAergic dysfunction is believed to contribute to many of the phenotypic deficits seen in AS. We hypothesized that restoration of inhibitory tone mediated by extrasynaptic GABAA receptors could provide therapeutic benefit. Here, we report that ganaxolone, a synthetic neurosteroid that acts as a positive allosteric modulator of synaptic and extrasynaptic GABAA receptors, was anxiolytic, anticonvulsant, and improved motor deficits in the Ube3a-deficient mouse model of AS when administered by implanted mini-pump for 3 days or 4 weeks. Treatment for 4 weeks also led to recovery of spatial working memory and hippocampal synaptic plasticity deficits. This study demonstrates that ganaxolone ameliorates many of the behavioral abnormalities in the adult AS mouse, and tolerance did not occur to the therapeutic effects of the drug. The results support clinical studies to investigate ganaxolone as a symptomatic treatment for AS.
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Affiliation(s)
- Stephanie L Ciarlone
- USF Health Byrd Alzheimer's Institute, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Xinming Wang
- USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - Michael A Rogawski
- Departments of Neurology and Pharmacology, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - Edwin J Weeber
- USF Health Byrd Alzheimer's Institute, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA.
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66
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Yin J, Schaaf CP. Autism genetics - an overview. Prenat Diagn 2016; 37:14-30. [DOI: 10.1002/pd.4942] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Jiani Yin
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston TX USA
| | - Christian P. Schaaf
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston TX USA
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67
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Tan WH, Bird LM. Angelman syndrome: Current and emerging therapies in 2016. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2016; 172:384-401. [PMID: 27860204 DOI: 10.1002/ajmg.c.31536] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by a loss of the maternally-inherited UBE3A; the paternal UBE3A is silenced in neurons by a mechanism involving an antisense transcript (UBE3A-AS) at the unmethylated paternal locus. We reviewed all published information on the clinical trials that have been completed as well as the publicly available information on ongoing trials of therapies in AS. To date, all clinical trials that strove to improve neurodevelopment in AS have been unsuccessful. Attempts at hypermethylating the maternal locus through dietary compounds were ineffective. The results of an 8-week open-label trial using minocycline as a matrix metalloproteinase-9 inhibitor were inconclusive, while a subsequent randomized placebo-controlled trial suggested that treatment with minocycline for 8 weeks did not result in any neurodevelopmental gains. A 1-year randomized placebo-controlled trial using levodopa to alter the phosphorylation of calcium/calmodulin-dependent kinase II did not lead to any improvement in neurodevelopment. Topoisomerase inhibitors and antisense oligonucleotides are being developed to directly inhibit UBE3A-AS. Artificial transcription factors are being developed to "super activate" UBE3A or inhibit UBE3A-AS. Other strategies targeting specific pathways are briefly discussed. We also reviewed the medications that are currently used to treat seizures and sleep disturbances, which are two of the more common complications of AS. © 2016 Wiley Periodicals, Inc.
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68
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Zhong W, Johnson CM, Wu Y, Cui N, Xing H, Zhang S, Jiang C. Effects of early-life exposure to THIP on phenotype development in a mouse model of Rett syndrome. J Neurodev Disord 2016; 8:37. [PMID: 27777634 PMCID: PMC5069883 DOI: 10.1186/s11689-016-9169-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/04/2016] [Indexed: 01/15/2023] Open
Abstract
Background Rett syndrome (RTT) is a neurodevelopmental disorder caused mostly by disruptions in the MECP2 gene. MECP2-null mice show imbalances in neuronal excitability and synaptic communications. Several previous studies indicate that augmenting synaptic GABA receptors (GABAARs) can alleviate RTT-like symptoms in mice. In addition to the synaptic GABAARs, there is a group of GABAARs found outside the synaptic cleft with the capability to produce sustained inhibition, which may be potential therapeutic targets for the control of neuronal excitability in RTT. Methods Wild-type and MECP2-null mice were randomly divided into four groups, receiving the extrasynaptic GABAAR agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol hydrochloride (THIP) and vehicle control, respectively. Low-dose THIP was administered to neonatal mice through lactation. RTT-like symptoms including lifespan, breathing, motor function, and social behaviors were studied when mice became mature. Changes in neuronal excitability and norepinephrine biosynthesis enzyme expression were studied in electrophysiology and molecular biology. Results With no evident sedation and other adverse side effects, early-life exposure to THIP extended the lifespan, alleviated breathing abnormalities, enhanced motor function, and improved social behaviors of MECP2-null mice. Such beneficial effects were associated with stabilization of locus coeruleus neuronal excitability and improvement of norepinephrine biosynthesis enzyme expression. Conclusions THIP treatment in early lives might be a therapeutic approach to RTT-like symptoms in MECP2-null mice and perhaps in people with RTT as well.
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Affiliation(s)
- Weiwei Zhong
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA 30302-4010 USA
| | | | - Yang Wu
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA 30302-4010 USA
| | - Ningren Cui
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA 30302-4010 USA
| | - Hao Xing
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA 30302-4010 USA
| | - Shuang Zhang
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA 30302-4010 USA
| | - Chun Jiang
- Department of Biology, Georgia State University, 100 Piedmont Avenue, Atlanta, GA 30302-4010 USA
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Ciarlone SL, Grieco JC, D'Agostino DP, Weeber EJ. Ketone ester supplementation attenuates seizure activity, and improves behavior and hippocampal synaptic plasticity in an Angelman syndrome mouse model. Neurobiol Dis 2016; 96:38-46. [PMID: 27546058 DOI: 10.1016/j.nbd.2016.08.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/28/2016] [Accepted: 08/16/2016] [Indexed: 12/31/2022] Open
Abstract
Angelman syndrome (AS) is a rare genetic and neurological disorder presenting with seizures, developmental delay, ataxia, and lack of speech. Previous studies have indicated that oxidative stress-dependent metabolic dysfunction may underlie the phenotypic deficits reported in the AS mouse model. While the ketogenic diet (KD) has been used to protect against oxidative stress and has successfully treated refractory epilepsy in AS case studies, issues arise due to its strict adherence requirements, in addition to selective eating habits and weight issues reported in patients with AS. We hypothesized that ketone ester supplementation would mimic the KD as an anticonvulsant and improve the behavioral and synaptic plasticity deficits in vivo. AS mice were supplemented R,S-1,3-butanediol acetoacetate diester (KE) ad libitum for eight weeks. KE administration improved motor coordination, learning and memory, and synaptic plasticity in AS mice. The KE was also anticonvulsant and altered brain amino acid metabolism in AS treated animals. Our findings suggest that KE supplementation produces sustained ketosis and ameliorates many phenotypes in the AS mouse model, and should be investigated further for future clinical use.
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Affiliation(s)
- Stephanie L Ciarlone
- USF Health Byrd Alzheimer's Institute, Tampa, FL 33613, United States; Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33620, United States
| | - Joseph C Grieco
- USF Health Byrd Alzheimer's Institute, Tampa, FL 33613, United States; Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33620, United States
| | - Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33620, United States
| | - Edwin J Weeber
- USF Health Byrd Alzheimer's Institute, Tampa, FL 33613, United States; Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33620, United States.
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70
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Jaenisch N, Liebmann L, Guenther M, Hübner CA, Frahm C, Witte OW. Reduced tonic inhibition after stroke promotes motor performance and epileptic seizures. Sci Rep 2016; 6:26173. [PMID: 27188341 PMCID: PMC4870642 DOI: 10.1038/srep26173] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/28/2016] [Indexed: 01/19/2023] Open
Abstract
Stroke survivors often recover from motor deficits, either spontaneously or with the support of rehabilitative training. Since tonic GABAergic inhibition controls network excitability, it may be involved in recovery. Middle cerebral artery occlusion in rodents reduces tonic GABAergic inhibition in the structurally intact motor cortex (M1). Transcript and protein abundance of the extrasynaptic GABAA-receptor complex α4β3δ are concurrently reduced (δ-GABAARs). In vivo and in vitro analyses show that stroke-induced glutamate release activates NMDA receptors, thereby reducing KCC2 transporters and down-regulates δ-GABAARs. Functionally, this is associated with improved motor performance on the RotaRod, a test in which mice are forced to move in a similar manner to rehabilitative training sessions. As an adverse side effect, decreased tonic inhibition facilitates post-stroke epileptic seizures. Our data imply that early and sometimes surprisingly fast recovery following stroke is supported by homeostatic, endogenous plasticity of extrasynaptic GABAA receptors.
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Affiliation(s)
- Nadine Jaenisch
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, Jena University Hospital, D-07743 Jena, Germany
| | - Madlen Guenther
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
| | - Christian A. Hübner
- Institute of Human Genetics, Jena University Hospital, D-07743 Jena, Germany
| | - Christiane Frahm
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
| | - Otto W. Witte
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
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Judson MC, Wallace ML, Sidorov MS, Burette AC, Gu B, van Woerden GM, King IF, Han JE, Zylka MJ, Elgersma Y, Weinberg RJ, Philpot BD. GABAergic Neuron-Specific Loss of Ube3a Causes Angelman Syndrome-Like EEG Abnormalities and Enhances Seizure Susceptibility. Neuron 2016; 90:56-69. [PMID: 27021170 DOI: 10.1016/j.neuron.2016.02.040] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 01/17/2016] [Accepted: 02/24/2016] [Indexed: 11/19/2022]
Abstract
Loss of maternal UBE3A causes Angelman syndrome (AS), a neurodevelopmental disorder associated with severe epilepsy. We previously implicated GABAergic deficits onto layer (L) 2/3 pyramidal neurons in the pathogenesis of neocortical hyperexcitability, and perhaps epilepsy, in AS model mice. Here we investigate consequences of selective Ube3a loss from either GABAergic or glutamatergic neurons, focusing on the development of hyperexcitability within L2/3 neocortex and in broader circuit and behavioral contexts. We find that GABAergic Ube3a loss causes AS-like increases in neocortical EEG delta power, enhances seizure susceptibility, and leads to presynaptic accumulation of clathrin-coated vesicles (CCVs)-all without decreasing GABAergic inhibition onto L2/3 pyramidal neurons. Conversely, glutamatergic Ube3a loss fails to yield EEG abnormalities, seizures, or associated CCV phenotypes, despite impairing tonic inhibition onto L2/3 pyramidal neurons. These results substantiate GABAergic Ube3a loss as the principal cause of circuit hyperexcitability in AS mice, lending insight into ictogenic mechanisms in AS.
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Affiliation(s)
- Matthew C Judson
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Michael L Wallace
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Michael S Sidorov
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Alain C Burette
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Bin Gu
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Geeske M van Woerden
- Department of Neuroscience, Erasmus Medical Center, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands; ENCORE Center for Neurodevelopmental Disorders, Erasmus Medical Center, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Ian F King
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ji Eun Han
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mark J Zylka
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ype Elgersma
- Department of Neuroscience, Erasmus Medical Center, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands; ENCORE Center for Neurodevelopmental Disorders, Erasmus Medical Center, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Richard J Weinberg
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Benjamin D Philpot
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA.
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Loss of UBE3A from TH-expressing neurons suppresses GABA co-release and enhances VTA-NAc optical self-stimulation. Nat Commun 2016; 7:10702. [PMID: 26869263 PMCID: PMC4754338 DOI: 10.1038/ncomms10702] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/13/2016] [Indexed: 01/06/2023] Open
Abstract
Motivated reward-seeking behaviours are governed by dopaminergic ventral tegmental area projections to the nucleus accumbens. In addition to dopamine, these mesoaccumbal terminals co-release other neurotransmitters including glutamate and GABA, whose roles in regulating motivated behaviours are currently being investigated. Here we demonstrate that loss of the E3-ubiquitin ligase, UBE3A, from tyrosine hydroxylase-expressing neurons impairs mesoaccumbal, non-canonical GABA co-release and enhances reward-seeking behaviour measured by optical self-stimulation. Mesoaccumbal terminals within the VTA are known to co-release both GABA and dopamine, although the functional role of the former has yet to be determined. Here, the authors find that non-canonical GABA release is regulated by the E3-ubiquitin ligase, UBE3A, and enhances optogenetic self-stimulation.
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Maternal Ube3a Loss Disrupts Sleep Homeostasis But Leaves Circadian Rhythmicity Largely Intact. J Neurosci 2016; 35:13587-98. [PMID: 26446213 DOI: 10.1523/jneurosci.2194-15.2015] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Individuals with Angelman syndrome (AS) suffer sleep disturbances that severely impair quality of life. Whether these disturbances arise from sleep or circadian clock dysfunction is currently unknown. Here, we explored the mechanistic basis for these sleep disorders in a mouse model of Angelman syndrome (Ube3a(m-/p+) mice). Genetic deletion of the maternal Ube3a allele practically eliminates UBE3A protein from the brain of Ube3a(m-/p+) mice, because the paternal allele is epigenetically silenced in most neurons. However, we found that UBE3A protein was present in many neurons of the suprachiasmatic nucleus--the site of the mammalian circadian clock--indicating that Ube3a can be expressed from both parental alleles in this brain region in adult mice. We found that while Ube3a(m-/p+) mice maintained relatively normal circadian rhythms of behavior and light-resetting, these mice exhibited consolidated locomotor activity and skipped the timed rest period (siesta) present in wild-type (Ube3a(m+/p+)) mice. Electroencephalographic analysis revealed that alterations in sleep regulation were responsible for these overt changes in activity. Specifically, Ube3a(m-/p+) mice have a markedly reduced capacity to accumulate sleep pressure, both during their active period and in response to forced sleep deprivation. Thus, our data indicate that the siesta is governed by sleep pressure, and that Ube3a is an important regulator of sleep homeostasis. These preclinical findings suggest that therapeutic interventions that target mechanisms of sleep homeostasis may improve sleep quality in individuals with AS. SIGNIFICANCE STATEMENT Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by loss of expression of the maternal copy of the UBE3A gene. Individuals with AS have severe sleep dysfunction that affects their cognition and presents challenges to their caregivers. Unfortunately, current treatment strategies have limited efficacy due to a poor understanding of the mechanisms underlying sleep disruptions in AS. Here we demonstrate that abnormal sleep patterns arise from a deficit in accumulation of sleep drive, uncovering the Ube3a gene as a novel genetic regulator of sleep homeostasis. Our findings encourage a re-evaluation of current treatment strategies for sleep dysfunction in AS, and suggest that interventions that promote increased sleep drive may alleviate sleep disturbances in individuals with AS.
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75
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Pharmacological therapies for Angelman syndrome. Wien Med Wochenschr 2016; 167:205-218. [PMID: 26758979 DOI: 10.1007/s10354-015-0408-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/15/2015] [Indexed: 12/16/2022]
Abstract
Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by a loss of the maternally inherited UBE3A; the paternal UBE3A is silenced in neurons by a mechanism involving an antisense transcript (UBE3A-AS). We reviewed the published information on clinical trials that have been completed as well as the publicly available information on ongoing trials of therapies for AS. Attempts at hypermethylating the maternal locus through dietary compounds were ineffective. The results of a clinical trial using minocycline as a matrix metalloproteinase-9 inhibitor were inconclusive; another clinical trial is underway. Findings from a clinical trial using L-dopa to alter phosphorylation of calcium/calmodulin-dependent kinase II are awaited. Topoisomerase inhibitors and antisense oligonucleotides are being developed to directly inhibit UBE3A-AS. Other strategies targeting specific pathways are briefly discussed. We also reviewed the medications that are currently used to treat seizures and sleep disturbances, which are two of the more debilitating manifestations of AS.
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76
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Abstract
INTRODUCTION Angelman syndrome (AS) is a neurodevelopmental disorder caused by deficiency of maternally inherited UBE3A, an ubiquitin E3 ligase. Despite recent progress in understanding the mechanism underlying UBE3A imprinting, there is no effective treatment. Further investigation of the roles played by UBE3A in the central nervous system (CNS) is needed for developing effective therapies. AREA COVERED This review covers the literature related to genetic classifications of AS, recent discoveries regarding the regulation of UBE3A imprinting, alterations in cell signaling in various brain regions and potential therapeutic approaches. Since a large proportion of AS patients exhibit comorbid autism spectrum disorder (ASD), potential common molecular bases are discussed. EXPERT OPINION Advances in understanding UBE3A imprinting provide a unique opportunity to induce paternal UBE3A expression, thus targeting the syndrome at its 'root.' However, such efforts have yielded less-than-expected rescue effects in AS mouse models, raising the concern that activation of paternal UBE3A after a critical period cannot correct all the CNS defects that developed in a UBE3A-deficient environment. On the other hand, targeting abnormal downstream cell signaling pathways has provided promising rescue effects in preclinical research. Thus, combined reinstatement of paternal UBE3A expression with targeting abnormal signaling pathways should provide better therapeutic effects.
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Affiliation(s)
- Xiaoning Bi
- a Department of Basic Medical Sciences, COMP , Western University of Health Sciences , Pomona , CA , USA
| | - Jiandong Sun
- a Department of Basic Medical Sciences, COMP , Western University of Health Sciences , Pomona , CA , USA
| | - Angela X Ji
- a Department of Basic Medical Sciences, COMP , Western University of Health Sciences , Pomona , CA , USA
| | - Michel Baudry
- b Graduate College of Biomedical Sciences , Western University of Health Sciences , Pomona , CA , USA
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Bruinsma CF, Schonewille M, Gao Z, Aronica EM, Judson MC, Philpot BD, Hoebeek FE, van Woerden GM, De Zeeuw CI, Elgersma Y. Dissociation of locomotor and cerebellar deficits in a murine Angelman syndrome model. J Clin Invest 2015; 125:4305-15. [PMID: 26485287 PMCID: PMC4639977 DOI: 10.1172/jci83541] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/10/2015] [Indexed: 12/13/2022] Open
Abstract
Angelman syndrome (AS) is a severe neurological disorder that is associated with prominent movement and balance impairments that are widely considered to be due to defects of cerebellar origin. Here, using the cerebellar-specific vestibulo-ocular reflex (VOR) paradigm, we determined that cerebellar function is only mildly impaired in the Ube3am-/p+ mouse model of AS. VOR phase-reversal learning was singularly impaired in these animals and correlated with reduced tonic inhibition between Golgi cells and granule cells. Purkinje cell physiology, in contrast, was normal in AS mice as shown by synaptic plasticity and spontaneous firing properties that resembled those of controls. Accordingly, neither VOR phase-reversal learning nor locomotion was impaired following selective deletion of Ube3a in Purkinje cells. However, genetic normalization of αCaMKII inhibitory phosphorylation fully rescued locomotor deficits despite failing to improve cerebellar learning in AS mice, suggesting extracerebellar circuit involvement in locomotor learning. We confirmed this hypothesis through cerebellum-specific reinstatement of Ube3a, which ameliorated cerebellar learning deficits but did not rescue locomotor deficits. This double dissociation of locomotion and cerebellar phenotypes strongly suggests that the locomotor deficits of AS mice do not arise from impaired cerebellar cortex function. Our results provide important insights into the etiology of the motor deficits associated with AS.
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Affiliation(s)
- Caroline F. Bruinsma
- Department of Neuroscience and
- ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, Netherlands
| | | | | | | | - Matthew C. Judson
- Department of Cell Biology and Physiology, Neuroscience Center, and Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Benjamin D. Philpot
- Department of Cell Biology and Physiology, Neuroscience Center, and Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, North Carolina, USA
| | | | - Geeske M. van Woerden
- Department of Neuroscience and
- ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, Netherlands
| | - Chris I. De Zeeuw
- Department of Neuroscience and
- ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Ype Elgersma
- Department of Neuroscience and
- ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, Netherlands
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Kaja S, Payne AJ, Nielsen EØ, Thompson CL, van den Maagdenberg AMJM, Koulen P, Snutch TP. Differential cerebellar GABAA receptor expression in mice with mutations in CaV2.1 (P/Q-type) calcium channels. Neuroscience 2015; 304:198-208. [PMID: 26208839 PMCID: PMC4547859 DOI: 10.1016/j.neuroscience.2015.07.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022]
Abstract
Ataxia is the predominant clinical manifestation of cerebellar dysfunction. Mutations in the human CACNA1A gene, encoding the pore-forming α1 subunit of CaV2.1 (P/Q-type) calcium channels, underlie several neurological disorders, including Episodic Ataxia type 2 and Familial Hemiplegic Migraine type 1 (FHM1). Several mouse mutants exist that harbor mutations in the orthologous Cacna1a gene. The spontaneous Cacna1a mutants Rolling Nagoya (tg(rol)), Tottering (tg) and Leaner (tg(ln)) mice exhibit behavioral motor phenotypes, including ataxia. Transgenic knock-in (KI) mouse strains with the human FHM1 R192Q and S218L missense mutations have been generated. R192Q KI mice are non-ataxic, whereas S218L KI mice display a complex behavioral phenotype that includes cerebellar ataxia. Given the dependence of γ-aminobutyric acid type A (GABAA) receptor subunit functioning on localized calcium currents, and the functional link between GABAergic inhibition and ataxia, we hypothesized that cerebellar GABAA receptor expression is differentially affected in Cacna1a mutants and contributes to the ataxic phenotype. Herein we quantified functional GABAA receptors and pharmacologically dissociated cerebellar GABAA receptors in several Cacna1a mutants. We did not identify differences in the expression of GABAA receptor subunits or in the number of functional GABAA receptors in the non-ataxic R192Q KI strain. In contrast, tg(rol) mice had a ∼15% decrease in the number of functional GABAA receptors, whereas S218L KI mice showed a ∼29% increase. Our data suggest that differential changes in cerebellar GABAA receptor expression profile may contribute to the neurological phenotype of cerebellar ataxia and that targeting GABAA receptors might represent a feasible complementary strategy to treat cerebellar ataxia.
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Affiliation(s)
- S Kaja
- Michael Smith Laboratories and the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 301-2185 East Mall, Vancouver, BC V6T 1Z4, Canada; NeuroSearch A/S, Pederstrupvej 93, 2750 Ballerup, Denmark; Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes Street, Kansas City, MO 64108, USA; K&P Scientific LLC, 8570 N Hickory Street Suite 412, Kansas City, MO 64155, USA.
| | - A J Payne
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes Street, Kansas City, MO 64108, USA; K&P Scientific LLC, 8570 N Hickory Street Suite 412, Kansas City, MO 64155, USA
| | - E Ø Nielsen
- NeuroSearch A/S, Pederstrupvej 93, 2750 Ballerup, Denmark
| | - C L Thompson
- School of Biological Sciences, Durham University, South Road, Science Laboratories, Durham DH1 3LE, United Kingdom
| | - A M J M van den Maagdenberg
- Departments of Human Genetics & Neurology, Leiden University Medical Centre, Einthovenweg 20, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - P Koulen
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes Street, Kansas City, MO 64108, USA; Department of Basic Medical Science, University of Missouri - Kansas City, School of Medicine, 2411 Holmes Street, Kansas City, MO 64108, USA
| | - T P Snutch
- Michael Smith Laboratories and the Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 301-2185 East Mall, Vancouver, BC V6T 1Z4, Canada
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79
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Sell GL, Margolis SS. From UBE3A to Angelman syndrome: a substrate perspective. Front Neurosci 2015; 9:322. [PMID: 26441497 PMCID: PMC4569740 DOI: 10.3389/fnins.2015.00322] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/28/2015] [Indexed: 01/15/2023] Open
Abstract
Angelman syndrome (AS) is a debilitating neurodevelopmental disorder that is characterized by motor dysfunction, intellectual disability, speech impairment, seizures and common features of autism spectrum disorders (ASDs). Some of these AS related phenotypes can be seen in other neurodevelopmental disorders (Williams, 2011; Tan et al., 2014). AS patients commonly carry mutations that render the maternally inherited UBE3A gene non-functional. Duplication of the chromosomal region containing the UBE3A gene is associated with ASDs. Although the causative role for UBE3A gene mutations in AS is well established, a long-standing challenge in AS research has been to identify neural substrates of UBE3A, an E3 ubiquitin ligase. A prevailing hypothesis is that changes in UBE3A protein levels would alter the levels of a collection of protein substrates, giving rise to the unique phenotypic aspects of AS and possibly UBE3A associated ASDs. Interestingly, proteins altered in AS are linked to additional ASDs that are not previously associated with changes in UBE3A, indicating a possible molecular overlap underlying the broad-spectrum phenotypes of these neurogenetic disorders. This idea raises the possibility that there may exist a “one-size-fits-all” approach to the treatment of neurogenetic disorders with phenotypes overlapping AS. Furthermore, while a comprehensive list of UBE3A substrates and downstream affected pathways should be developed, this is only part of the story. The timing of when UBE3A protein functions, through either changes in UBE3A or possibly substrate expression patterns, appears to be critical for AS phenotype development. These data call for further investigation of UBE3A substrates and their timing of action relevant to AS phenotypes.
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Affiliation(s)
- Gabrielle L Sell
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine Baltimore, MD, USA ; Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Seth S Margolis
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine Baltimore, MD, USA ; Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine Baltimore, MD, USA
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80
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Valdez C, Scroggs R, Chassen R, Reiter LT. Variation in Dube3a expression affects neurotransmission at the Drosophila neuromuscular junction. Biol Open 2015; 4:776-82. [PMID: 25948754 PMCID: PMC4571101 DOI: 10.1242/bio.20148045] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Changes in UBE3A expression levels in neurons can cause neurogenetic disorders ranging from Angelman syndrome (AS) (decreased levels) to autism (increased levels). Here we investigated the effects on neuronal function of varying UBE3A levels using the Drosophila neuromuscular junction as a model for both of these neurogenetic disorders. Stimulations that evoked excitatory junction potentials (EJPs) at 1 Hz intermittently failed to evoke EJPs at 15 Hz in a significantly higher proportion of Dube3a over-expressors using the pan neuronal GAL4 driver C155-GAL4 (C155-GAL4>UAS-Dube3a) relative to controls (C155>+ alone). However, in the Dube3a over-expressing larval neurons with no failures, there was no difference in EJP amplitude at the beginning of the train, or the rate of decrease in EJP amplitude over the course of the train compared to controls. In the absence of tetrodotoxin (TTX), spontaneous EJPs were observed in significantly more C155-GAL4>UAS-Dube3a larva compared to controls. In the presence of TTX, spontaneous and evoked EJPs were completely blocked and mEJP amplitude and frequency did not differ among genotypes. These data suggest that over-expression of wild type Dube3a, but not a ubiquitination defective Dube3a-C/A protein, compromises the ability of motor neuron axons to support closely spaced trains of action potentials, while at the same time increasing excitability. EJPs evoked at 15 Hz in the absence of Dube3a (Dube3a15b homozygous mutant larvae) decayed more rapidly over the course of 30 stimulations compared to w1118 controls, and Dube3a15b larval muscles had significantly more negative resting membrane potentials (RMP). However, these results could not be recapitulated using RNAi knockdown of Dube3a in muscle or neurons alone, suggesting more global developmental defects contribute to this phenotype. These data suggest that reduced UBE3A expression levels may cause global changes that affect RMP and neurotransmitter release from motorneurons at the neuromuscular junction. Similar affects of under- and over-expression of UBE3A on membrane potential and synaptic transmission may underlie the synaptic plasticity defects observed in both AS and autism.
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Affiliation(s)
- Colleen Valdez
- Department of Neurology, The University of Tennessee Health Science Center, 855 Monroe Ave., Link 415, Memphis, TN 38163, USA
| | - Reese Scroggs
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, 855 Monroe Ave., Link 515, Memphis, TN 38163, USA
| | - Rachel Chassen
- Department of Neurology, The University of Tennessee Health Science Center, 855 Monroe Ave., Link 415, Memphis, TN 38163, USA
| | - Lawrence T Reiter
- Department of Neurology, The University of Tennessee Health Science Center, 855 Monroe Ave., Link 415, Memphis, TN 38163, USA Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, 855 Monroe Ave., Link 515, Memphis, TN 38163, USA
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81
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Mandel-Brehm C, Salogiannis J, Dhamne SC, Rotenberg A, Greenberg ME. Seizure-like activity in a juvenile Angelman syndrome mouse model is attenuated by reducing Arc expression. Proc Natl Acad Sci U S A 2015; 112:5129-34. [PMID: 25848016 PMCID: PMC4413330 DOI: 10.1073/pnas.1504809112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder arising from loss-of-function mutations in the maternally inherited copy of the UBE3A gene, and is characterized by an absence of speech, excessive laughter, cognitive delay, motor deficits, and seizures. Despite the fact that the symptoms of AS occur in early childhood, behavioral characterization of AS mouse models has focused primarily on adult phenotypes. In this report we describe juvenile behaviors in AS mice that are strain-independent and clinically relevant. We find that young AS mice, compared with their wild-type littermates, produce an increased number of ultrasonic vocalizations. In addition, young AS mice have defects in motor coordination, as well as abnormal brain activity that results in an enhanced seizure-like response to an audiogenic challenge. The enhanced seizure-like activity, but not the increased ultrasonic vocalizations or motor deficits, is rescued in juvenile AS mice by genetically reducing the expression level of the activity-regulated cytoskeleton-associated protein, Arc. These findings suggest that therapeutic interventions that reduce the level of Arc expression have the potential to reverse the seizures associated with AS. In addition, the identification of aberrant behaviors in young AS mice may provide clues regarding the neural circuit defects that occur in AS and ultimately allow new approaches for treating this disorder.
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Affiliation(s)
| | | | - Sameer C Dhamne
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
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82
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Judson MC, Sosa-Pagan JO, Del Cid WA, Han JE, Philpot BD. Allelic specificity of Ube3a expression in the mouse brain during postnatal development. J Comp Neurol 2014; 522:1874-96. [PMID: 24254964 DOI: 10.1002/cne.23507] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 10/30/2013] [Accepted: 11/15/2013] [Indexed: 12/23/2022]
Abstract
Genetic alterations of the maternal UBE3A allele result in Angelman syndrome (AS), a neurodevelopmental disorder characterized by severe developmental delay, lack of speech, and difficulty with movement and balance. The combined effects of maternal UBE3A mutation and cell type-specific epigenetic silencing of paternal UBE3A are hypothesized to result in a complete loss of functional UBE3A protein in neurons. However, the allelic specificity of UBE3A expression in neurons and other cell types in the brain has yet to be characterized throughout development, including the early postnatal period when AS phenotypes emerge. Here we define maternal and paternal allele-specific Ube3a protein expression throughout postnatal brain development in the mouse, a species that exhibits orthologous epigenetic silencing of paternal Ube3a in neurons and AS-like behavioral phenotypes subsequent to maternal Ube3a deletion. We find that neurons downregulate paternal Ube3a protein expression as they mature and, with the exception of neurons born from postnatal stem cell niches, do not express detectable paternal Ube3a beyond the first postnatal week. By contrast, neurons express maternal Ube3a throughout postnatal development, during which time localization of the protein becomes increasingly nuclear. Unlike neurons, astrocytes and oligodendrotyes biallelically express Ube3a. Notably, mature oligodendrocytes emerge as the predominant Ube3a-expressing glial cell type in the cortex and white matter tracts during postnatal development. These findings demonstrate the spatiotemporal characteristics of allele-specific Ube3a expression in key brain cell types, thereby improving our understanding of the developmental parameters of paternal Ube3a silencing and the cellular basis of AS.
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Affiliation(s)
- Matthew C Judson
- Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, 27599
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83
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Grieco JC, Ciarlone SL, Gieron-Korthals M, Schoenberg MR, Smith AG, Philpot RM, Heussler HS, Banko JL, Weeber EJ. An open-label pilot trial of minocycline in children as a treatment for Angelman syndrome. BMC Neurol 2014; 14:232. [PMID: 25491305 PMCID: PMC4276108 DOI: 10.1186/s12883-014-0232-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 11/24/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Minocycline, a member of the tetracycline family, has a low risk of adverse effects and an ability to improve behavioral performance in humans with cognitive disruption. We performed a single-arm open-label trial in which 25 children diagnosed with Angelman syndrome (AS) were administered minocycline to assess the safety and tolerability of minocycline in this patient population and determine the drug's effect on the cognitive and behavioral manifestations of the disorder. METHODS Participants, age 4-12 years old, were randomly selected from a pool of previously screened children for participation in this study. Each child received 3 milligrams of minocycline per kilogram of body weight per day for 8 weeks. Participants were assessed during 3 study visits: baseline, after 8-weeks of minocycline treatment and after an 8-week wash out period. The primary outcome measure was the Bayley Scales of Infant and Toddler Development 3rd Edition (BSID-III). Secondary outcome measures included the Clinical Global Impressions Scale (CGI), Vineland Adaptive Behavior Scales 2nd Edition (VABS-II), Preschool Language Scale 4th Edition (PLS-IV) and EEG scores. Observations were considered statistically significant if p < 0.05 using ANOVA and partial eta squared (η(2)) was calculated to show effect size. Multiple comparisons testing between time points were carried out using Dunnett's post hoc testing. RESULTS Significant improvement in the mean raw scores of the BSID-III subdomains communication and fine motor ability as well as the subdomains auditory comprehension and total language ability of the PLS-IV when baseline scores were compared to scores after the washout period. Further, improvements were observed in the receptive communication subdomain of the VABS-II after treatment with minocycline. Finally, mean scores of the BSID-III self-direction subdomain and CGI scale score were significantly improved both after minocycline treatment and after the wash out period. CONCLUSION The clinical and neuropsychological measures suggest minocycline was well tolerated and causes improvements in the adaptive behaviors of this sample of children with Angelman syndrome. While the optimal dosage and the effects of long-term use still need to be determined, these findings suggest further investigation into the effect minocycline has on patients with Angelman syndrome is warranted. TRIAL REGISTRATION NCT01531582 - clinicaltrials.gov.
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Affiliation(s)
- Joseph C Grieco
- Department of Molecular Pharmacology and Physiology, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
| | - Stephanie L Ciarlone
- Department of Molecular Pharmacology and Physiology, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
| | - Maria Gieron-Korthals
- Department of Pediatrics, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
- Department of Neurology, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
| | - Mike R Schoenberg
- Departments of Psychiatry and Behavioral Neurosciences, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
- Department of Neurology, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
- University of South Florida Health's Byrd Alzheimer's Research Institute, 4001 E Fletcher Avenue, Tampa, FL, 33613, USA.
| | - Amanda G Smith
- University of South Florida Health's Byrd Alzheimer's Research Institute, 4001 E Fletcher Avenue, Tampa, FL, 33613, USA.
| | - Rex M Philpot
- Departments of Psychiatry and Behavioral Neurosciences, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
| | - Helen S Heussler
- Mater Research Institute, University of Queensland, St Lucia, QLD, 4072, Australia.
| | - Jessica L Banko
- University of South Florida Health's Byrd Alzheimer's Research Institute, 4001 E Fletcher Avenue, Tampa, FL, 33613, USA.
| | - Edwin J Weeber
- Department of Molecular Pharmacology and Physiology, University of South Florida, Morsani College of Medicine, 12901 Bruce B Downs Boulevard, Tampa, FL, 33612, USA.
- University of South Florida Health's Byrd Alzheimer's Research Institute, 4001 E Fletcher Avenue, Tampa, FL, 33613, USA.
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84
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Cheron G, Márquez-Ruiz J, Kishino T, Dan B. Disruption of the LTD dialogue between the cerebellum and the cortex in Angelman syndrome model: a timing hypothesis. Front Syst Neurosci 2014; 8:221. [PMID: 25477791 PMCID: PMC4237040 DOI: 10.3389/fnsys.2014.00221] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/25/2014] [Indexed: 12/11/2022] Open
Abstract
Angelman syndrome (AS) is a genetic neurodevelopmental disorder in which cerebellar functioning impairment has been documented despite the absence of gross structural abnormalities. Characteristically, a spontaneous 160 Hz oscillation emerges in the Purkinje cells network of the Ube3a (m-/p+) Angelman mouse model. This abnormal oscillation is induced by enhanced Purkinje cell rhythmicity and hypersynchrony along the parallel fiber beam. We present a pathophysiological hypothesis for the neurophysiology underlying major aspects of the clinical phenotype of AS, including cognitive, language and motor deficits, involving long-range connection between the cerebellar and the cortical networks. This hypothesis states that the alteration of the cerebellar rhythmic activity impinges cerebellar long-term depression (LTD) plasticity, which in turn alters the LTD plasticity in the cerebral cortex. This hypothesis was based on preliminary experiments using electrical stimulation of the whiskers pad performed in alert mice showing that after a 8 Hz LTD-inducing protocol, the cerebellar LTD accompanied by a delayed response in the wild type (WT) mice is missing in Ube3a (m-/p+) mice and that the LTD induced in the barrel cortex following the same peripheral stimulation in wild mice is reversed into a LTP in the Ube3a (m-/p+) mice. The control exerted by the cerebellum on the excitation vs. inhibition balance in the cerebral cortex and possible role played by the timing plasticity of the Purkinje cell LTD on the spike-timing dependent plasticity (STDP) of the pyramidal neurons are discussed in the context of the present hypothesis.
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Affiliation(s)
- Guy Cheron
- Laboratory of Electrophysiology, Université de MonsMons, Belgium
- Laboratory of Neurophysiology and Movement Biomechanics, ULB Neuroscience Institut, Université Libre de BruxellesBrussels, Belgium
| | | | - Tatsuya Kishino
- Division of Functional Genomics, Center for Frontier Life Sciences, Nagasaki UniversityNagasaki, Japan
| | - Bernard Dan
- Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de BruxellesBrussels, Belgium
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85
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Nielsen EØ, Kaja S. GABA A Receptor Expression in the Forebrain of Ataxic Rolling Nagoya Mice. BIOLOGY AND MEDICINE (ALIGARH) 2014; 6. [PMID: 25309056 DOI: 10.4172/1234-3425.1000198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human CACNA1A gene encodes the pore-forming α1 subunit of CaV2.1 (P/Q-type) calcium channels and is the locus for several neurological disorders, including episodic ataxia type 2 (EA2), spinocerebellar ataxia type 6 (SCA6) and Familial Hemiplegic Migraine type 1 (FHM1). Several spontaneous mouse Cacna1a mutant strains exist, among them Rolling Nagoya (tgrol), carrying the R1262G point mutation in the mouse Cacna1a gene. tgrol mice display a phenotype of severe gait ataxia and motor dysfunction of the hind limbs. At the functional level, the R1262G mutation results in a positive shift of the activation voltage of the CaV2.1 channel and reduced current density. γ-Aminobutyric acid type A (GABAA) receptor subunit expression depends critically on neuronal calcium influx, and GABAA receptor dysfunction has previously been described for the cerebellum of tgrol and other ataxic Cacna1a mutant mice. Given the expression pattern of CaV2.1, it was hypothesized that calcium dysregulation in tgrol might affect GABAA receptor expression in the forebrain. Herein, functional GABAA receptors in the forebrain of tgrol mice were quantified and pharmacologically dissociated using [3H] radioligand binding. No gross changes to functional GABAA receptors were identified. Future cell type-specific analyses are required to identify possible cortical contributions to the psychomotor phenotype of tgrol mice.
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Affiliation(s)
| | - Simon Kaja
- NeuroSearch A/S, Pederstrupvej 93, 2750 Ballerup, Denmark ; School of Biological and Biomedical Sciences, Durham University, South Road, Science Laboratories, Durham DH1 3LE, United Kingdom ; Vision Research Center, Department of Ophthalmology University of Missouri, Kansas City, School of Medicine, 2411 Holmes St., Kansas City, MO 64108, USA ; K&P Scientific LLC, 8570 N Hickory St. Ste. 412, Kansas City, MO 64155, USA
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86
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Yoon BE, Woo J, Chun YE, Chun H, Jo S, Bae JY, An H, Min JO, Oh SJ, Han KS, Kim HY, Kim T, Kim YS, Bae YC, Lee CJ. Glial GABA, synthesized by monoamine oxidase B, mediates tonic inhibition. J Physiol 2014; 592:4951-68. [PMID: 25239459 DOI: 10.1113/jphysiol.2014.278754] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
GABA is the major inhibitory transmitter in the brain and is released not only from a subset of neurons but also from glia. Although neuronal GABA is well known to be synthesized by glutamic acid decarboxylase (GAD), the source of glial GABA is unknown. After estimating the concentration of GABA in Bergmann glia to be around 5-10 mM by immunogold electron microscopy, we demonstrate that GABA production in glia requires MAOB, a key enzyme in the putrescine degradation pathway. In cultured cerebellar glia, both Ca(2+)-induced and tonic GABA release are significantly reduced by both gene silencing of MAOB and the MAOB inhibitor selegiline. In the cerebellum and striatum of adult mice, general gene silencing, knock out of MAOB or selegiline treatment resulted in elimination of tonic GABA currents recorded from granule neurons and medium spiny neurons. Glial-specific rescue of MAOB resulted in complete rescue of tonic GABA currents. Our results identify MAOB as a key synthesizing enzyme of glial GABA, which is released via bestrophin 1 (Best1) channel to mediate tonic inhibition in the brain.
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Affiliation(s)
- Bo-Eun Yoon
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Korea Department of Nanobiomedical Science, Dankook University, Chungnam, 330-714, Korea
| | - Junsung Woo
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Korea
| | - Ye-Eun Chun
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Korea
| | - Heejung Chun
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea
| | - Seonmi Jo
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Korea
| | - Jin Young Bae
- Department of Oral Anatomy and Neurobiology, BK21, School of Dentistry, Kyungpook National University, Daegu, 700-412, Republic of Korea
| | - Heeyoung An
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea KU-KIST School of Converging Science and Technology, Korea University, Seoul, 136-701, Korea
| | - Joo Ok Min
- Department of Nanobiomedical Science, Dankook University, Chungnam, 330-714, Korea
| | - Soo-Jin Oh
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea
| | - Kyung-Seok Han
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Korea
| | - Hye Yun Kim
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea
| | - Taekeun Kim
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea
| | - Young Soo Kim
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea
| | - Yong Chul Bae
- Department of Oral Anatomy and Neurobiology, BK21, School of Dentistry, Kyungpook National University, Daegu, 700-412, Republic of Korea
| | - C Justin Lee
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Korea
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87
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Hallengren JJ, Vaden RJ. Sodium-potassium ATPase emerges as a player in hippocampal phenotypes of Angelman syndrome mice. J Neurophysiol 2014; 112:5-8. [PMID: 24501262 PMCID: PMC4064391 DOI: 10.1152/jn.00760.2013] [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: 10/24/2013] [Accepted: 01/31/2014] [Indexed: 11/22/2022] Open
Abstract
Angelman syndrome is a neurodevelopmental disorder characterized by intellectual disabilities, ataxia, and unusually happy affect. The hippocampal pyramidal cells of Angelman syndrome model mice have altered intrinsic membrane properties, which Kaphzan et al. (Cell Rep 4: 405-412, 2013) demonstrate can be corrected by genetic reduction of the α1-subunit of the sodium-potassium ATPase. Intriguingly, this manipulation also restores hippocampal long-term potentiation and learning. In this Neuro Forum, we discuss translational implications of this work and remaining questions left in its wake.
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Affiliation(s)
- Jada J Hallengren
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ryan J Vaden
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama
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88
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Characteristic development of the GABA-removal system in the mouse spinal cord. Neuroscience 2014; 262:129-42. [DOI: 10.1016/j.neuroscience.2013.12.066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 12/28/2013] [Accepted: 12/31/2013] [Indexed: 11/24/2022]
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89
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Cellot G, Cherubini E. GABAergic signaling as therapeutic target for autism spectrum disorders. Front Pediatr 2014; 2:70. [PMID: 25072038 PMCID: PMC4085902 DOI: 10.3389/fped.2014.00070] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 06/23/2014] [Indexed: 11/13/2022] Open
Abstract
γ-Aminobutyric acid (GABA), the main inhibitory neurotransmitter in the adult brain, early in postnatal life exerts a depolarizing and excitatory action. This depends on accumulation of chloride inside the cell via the cation-chloride importer NKCC1, being the expression of the chloride exporter KCC2 very low at birth. The developmentally regulated expression of KCC2 results in extrusion of chloride with age and a shift of GABA from the depolarizing to the hyperpolarizing direction. The depolarizing action of GABA leads to intracellular calcium rise through voltage-dependent calcium channels and/or N-methyl-d-aspartate receptors. GABA-mediated calcium signals regulate a variety of developmental processes from cell proliferation migration, differentiation, synapse maturation, and neuronal wiring. Therefore, it is not surprising that some forms of neuro-developmental disorders such as autism spectrum disorders (ASDs) are associated with alterations of GABAergic signaling and impairment of the excitatory/inhibitory balance in selective neuronal circuits. In this review, we will discuss how changes of GABAA-mediated neurotransmission affect several forms of ASDs including the Fragile X, the Angelman, and Rett syndromes. Then, we will describe various animal models of ASDs with GABAergic dysfunctions, highlighting their behavioral deficits and the possibility to rescue them by targeting selective components of the GABAergic synapse. In particular, we will discuss how in some cases, reverting the polarity of GABA responses from the depolarizing to the hyperpolarizing direction with the diuretic bumetanide, a selective blocker of NKCC1, may have beneficial effects on ASDs, thus opening new therapeutic perspectives for the treatment of these devastating disorders.
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Affiliation(s)
- Giada Cellot
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy
| | - Enrico Cherubini
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy ; European Brain Research Institute , Rome , Italy
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90
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Lozano R, Hare EB, Hagerman RJ. Modulation of the GABAergic pathway for the treatment of fragile X syndrome. Neuropsychiatr Dis Treat 2014; 10:1769-79. [PMID: 25258535 PMCID: PMC4172237 DOI: 10.2147/ndt.s42919] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common genetic cause of intellectual disability and the most common single-gene cause of autism. It is caused by mutations on the fragile X mental retardation gene (FMR1) and lack of fragile X mental retardation protein, which in turn, leads to decreased inhibition of translation of many synaptic proteins. The metabotropic glutamate receptor (mGluR) hypothesis states that the neurological deficits in individuals with FXS are due mainly to downstream consequences of overstimulation of the mGluR pathway. The main efforts have focused on mGluR5 targeted treatments; however, investigation on the gamma-aminobutyric acid (GABA) system and its potential as a targeted treatment is less emphasized. The fragile X mouse models (Fmr1-knock out) show decreased GABA subunit receptors, decreased synthesis of GABA, increased catabolism of GABA, and overall decreased GABAergic input in many regions of the brain. Consequences of the reduced GABAergic input in FXS include oversensitivity to sensory stimuli, seizures, and anxiety. Deficits in the GABA receptors in different regions of the brain are associated with behavioral and attentional processing deficits linked to anxiety and autistic behaviors. The understanding of the neurobiology of FXS has led to the development of targeted treatments for the core behavioral features of FXS, which include social deficits, inattention, and anxiety. These symptoms are also observed in individuals with autism and other neurodevelopmental disorders, therefore the targeted treatments for FXS are leading the way in the treatment of other neurodevelopmental syndromes and autism. The GABAergic system in FXS represents a target for new treatments. Herein, we discuss the animal and human trials of GABAergic treatment in FXS. Arbaclofen and ganaxolone have been used in individuals with FXS. Other potential GABAergic treatments, such as riluzole, gaboxadol, tiagabine, and vigabatrin, will be also discussed. Further studies are needed to determine the safety and efficacy of GABAergic treatments for FXS.
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Affiliation(s)
- Reymundo Lozano
- MIND Institute, UC Davis Medical Center, Sacramento, CA, USA ; Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
| | - Emma B Hare
- MIND Institute, UC Davis Medical Center, Sacramento, CA, USA ; Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
| | - Randi J Hagerman
- MIND Institute, UC Davis Medical Center, Sacramento, CA, USA ; Department of Pediatrics, UC Davis Medical Center, Sacramento, CA, USA
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91
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Egawa K, Fukuda A. Pathophysiological power of improper tonic GABA(A) conductances in mature and immature models. Front Neural Circuits 2013; 7:170. [PMID: 24167475 PMCID: PMC3807051 DOI: 10.3389/fncir.2013.00170] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/28/2013] [Indexed: 11/25/2022] Open
Abstract
High-affinity extrasynaptic gamma-aminobutyric acid A (GABAA) receptors are tonically activated by low and consistent levels of ambient GABA, mediating chronic inhibition against neuronal excitability (tonic inhibition) and the modulation of neural development. Synaptic (phasic) inhibition is spatially and temporally precise compared with tonic inhibition, which provides blunt yet strong integral inhibitory force by shunting electrical signaling. Although effects of acute modification of tonic inhibition are known, its pathophysiological significance remains unclear because homeostatic regulation of neuronal excitability can compensate for long-term deficit of extrasynaptic GABAA receptor activation. Nevertheless, tonic inhibition is of great interest for its pathophysiological involvement in central nervous system (CNS) diseases and thus as a therapeutic target. Together with the development of experimental models for various pathological states, recent evidence demonstrates such pathological involvements of tonic inhibition in neuronal dysfunction. This review focuses on the recent progress of tonic activation of GABAA conductance on the development and pathology of the CNS. Findings indicate that neuronal function in various brain regions are exacerbated with a gain or loss of function of tonic inhibition by GABA spillover. Disturbance of tonic GABAA conductance mediated by non-synaptic ambient GABA may result in brain mal-development. Therefore, various pathological states (epilepsy, motor dysfunctions, psychiatric disorders, and neurodevelopmental disorders) may be partly attributable to abnormal tonic GABAA conductances. Thus, the tone of tonic conductance and level of ambient GABA may be precisely tuned to maintain the regular function and development of the CNS. Therefore, receptor expression and factors for regulating the ambient GABA concentration are highlighted to gain a deeper understanding of pathology and therapeutic strategy for CNS diseases.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Neurology, Massachusetts General Hospital Charlestown, MA, USA ; Department of Pediatrics, Hokkaido University Graduate School of Medicine Sapporo, Japan
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92
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Becker EBE, Stoodley CJ. Autism spectrum disorder and the cerebellum. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 113:1-34. [PMID: 24290381 DOI: 10.1016/b978-0-12-418700-9.00001-0] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The cerebellum has been long known for its importance in motor learning and coordination. Recently, anatomical, clinical, and neuroimaging studies strongly suggest that the cerebellum supports cognitive functions, including language and executive functions, as well as affective regulation. Furthermore, the cerebellum has emerged as one of the key brain regions affected in autism. Here, we discuss our current understanding of the role of the cerebellum in autism, including evidence from genetic, molecular, clinical, behavioral, and neuroimaging studies. Cerebellar findings in autism suggest developmental differences at multiple levels of neural structure and function, indicating that the cerebellum is an important player in the complex neural underpinnings of autism spectrum disorder, with behavioral implications beyond the motor domain.
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Affiliation(s)
- Esther B E Becker
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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