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Sieghart W, Chiou LC, Ernst M, Fabjan J, M Savić M, Lee MT. α6-Containing GABA A Receptors: Functional Roles and Therapeutic Potentials. Pharmacol Rev 2022; 74:238-270. [PMID: 35017178 DOI: 10.1124/pharmrev.121.000293] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/08/2021] [Indexed: 12/11/2022] Open
Abstract
GABAA receptors containing the α6 subunit are highly expressed in cerebellar granule cells and less abundantly in many other neuronal and peripheral tissues. Here, we for the first time summarize their importance for the functions of the cerebellum and the nervous system. The cerebellum is not only involved in motor control but also in cognitive, emotional, and social behaviors. α6βγ2 GABAA receptors located at cerebellar Golgi cell/granule cell synapses enhance the precision of inputs required for cerebellar timing of motor activity and are thus involved in cognitive processing and adequate responses to our environment. Extrasynaptic α6βδ GABAA receptors regulate the amount of information entering the cerebellum by their tonic inhibition of granule cells, and their optimal functioning enhances input filtering or contrast. The complex roles of the cerebellum in multiple brain functions can be compromised by genetic or neurodevelopmental causes that lead to a hypofunction of cerebellar α6-containing GABAA receptors. Animal models mimicking neuropsychiatric phenotypes suggest that compounds selectively activating or positively modulating cerebellar α6-containing GABAA receptors can alleviate essential tremor and motor disturbances in Angelman and Down syndrome as well as impaired prepulse inhibition in neuropsychiatric disorders and reduce migraine and trigeminal-related pain via α6-containing GABAA receptors in trigeminal ganglia. Genetic studies in humans suggest an association of the human GABAA receptor α6 subunit gene with stress-associated disorders. Animal studies support this conclusion. Neuroimaging and post-mortem studies in humans further support an involvement of α6-containing GABAA receptors in various neuropsychiatric disorders, pointing to a broad therapeutic potential of drugs modulating α6-containing GABAA receptors. SIGNIFICANCE STATEMENT: α6-Containing GABAA receptors are abundantly expressed in cerebellar granule cells, but their pathophysiological roles are widely unknown, and they are thus out of the mainstream of GABAA receptor research. Anatomical and electrophysiological evidence indicates that these receptors have a crucial function in neuronal circuits of the cerebellum and the nervous system, and experimental, genetic, post-mortem, and pharmacological studies indicate that selective modulation of these receptors offers therapeutic prospects for a variety of neuropsychiatric disorders and for stress and its consequences.
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Affiliation(s)
- Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences (W.S.), and Center for Brain Research, Department of Pathobiology of the Nervous System (M.E., J.F.), Medical University Vienna, Vienna, Austria; Graduate Institute of Pharmacology (L.-C.C., M.T.L.), and Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan (L.-C.C., M.T.L.); Faculty of Pharmacy, Department of Pharmacology, University of Belgrade, Belgrade, Serbia (M.M.S.); Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur, Malaysia (M.T.L.); and Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan (L.-C.C.)
| | - Lih-Chu Chiou
- Center for Brain Research, Department of Molecular Neurosciences (W.S.), and Center for Brain Research, Department of Pathobiology of the Nervous System (M.E., J.F.), Medical University Vienna, Vienna, Austria; Graduate Institute of Pharmacology (L.-C.C., M.T.L.), and Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan (L.-C.C., M.T.L.); Faculty of Pharmacy, Department of Pharmacology, University of Belgrade, Belgrade, Serbia (M.M.S.); Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur, Malaysia (M.T.L.); and Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan (L.-C.C.)
| | - Margot Ernst
- Center for Brain Research, Department of Molecular Neurosciences (W.S.), and Center for Brain Research, Department of Pathobiology of the Nervous System (M.E., J.F.), Medical University Vienna, Vienna, Austria; Graduate Institute of Pharmacology (L.-C.C., M.T.L.), and Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan (L.-C.C., M.T.L.); Faculty of Pharmacy, Department of Pharmacology, University of Belgrade, Belgrade, Serbia (M.M.S.); Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur, Malaysia (M.T.L.); and Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan (L.-C.C.)
| | - Jure Fabjan
- Center for Brain Research, Department of Molecular Neurosciences (W.S.), and Center for Brain Research, Department of Pathobiology of the Nervous System (M.E., J.F.), Medical University Vienna, Vienna, Austria; Graduate Institute of Pharmacology (L.-C.C., M.T.L.), and Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan (L.-C.C., M.T.L.); Faculty of Pharmacy, Department of Pharmacology, University of Belgrade, Belgrade, Serbia (M.M.S.); Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur, Malaysia (M.T.L.); and Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan (L.-C.C.)
| | - Miroslav M Savić
- Center for Brain Research, Department of Molecular Neurosciences (W.S.), and Center for Brain Research, Department of Pathobiology of the Nervous System (M.E., J.F.), Medical University Vienna, Vienna, Austria; Graduate Institute of Pharmacology (L.-C.C., M.T.L.), and Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan (L.-C.C., M.T.L.); Faculty of Pharmacy, Department of Pharmacology, University of Belgrade, Belgrade, Serbia (M.M.S.); Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur, Malaysia (M.T.L.); and Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan (L.-C.C.)
| | - Ming Tatt Lee
- Center for Brain Research, Department of Molecular Neurosciences (W.S.), and Center for Brain Research, Department of Pathobiology of the Nervous System (M.E., J.F.), Medical University Vienna, Vienna, Austria; Graduate Institute of Pharmacology (L.-C.C., M.T.L.), and Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan (L.-C.C., M.T.L.); Faculty of Pharmacy, Department of Pharmacology, University of Belgrade, Belgrade, Serbia (M.M.S.); Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur, Malaysia (M.T.L.); and Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan (L.-C.C.)
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Egawa K, Saitoh S, Asahina N, Shiraishi H. Variance in the pathophysiological impact of the hemizygosity of gamma-aminobutyric acid type A receptor subunit genes between Prader-Willi syndrome and Angelman syndrome. Brain Dev 2021; 43:521-527. [PMID: 33419637 DOI: 10.1016/j.braindev.2020.12.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/29/2020] [Accepted: 12/20/2020] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Angelman syndrome (AS) and Prader-Willi syndrome (PWS) are neurodevelopmental disorders caused by loss of function of maternally expressed UBE3A and paternally expressed contiguous genes on chromosome 15q11-13, respectively. A majority of these syndromes suffer from a large deletion of the relevant chromosome (AS Del or PWS Del), which includes biallelically expressed gamma-aminobutyric acid type A receptor subunit (GABAaR) genes, while remaining individuals present without the deletion (AS non-Del or PWS non-Del). We previously reported that AS Del, but not AS non-Del individuals, show aberrantly desynchronized somatosensory-evoked magnetic fields (SEFs) and speculated that it might reflect GABAergic dysfunction due to the hemizygosity of GABAaR genes. To verify its pathophysiological impact on PWS and AS, we analyzed the SEFs of PWS individuals. METHOD SEFs were recorded from eight PWS Del and two PWS non-Del individuals. The latency and strength of the first peak (N1m) were compared with those of AS Del/non-Del individuals and controls, most of which were obtained earlier. RESULTS In contrast to AS, both PWS Del and PWS non-Del showed normal SEF waveforms. Desynchronized response with delayed N1m peak latency was exclusively indicated in AS Del. N1m strength was statistically higher in AS Del and AS non-Del, but not in PWS Del and PWS non-Del. CONCLUSIONS Our results indicate that the pathophysiological impact of the hemizygosity of GABAaR genes is lower in PWS than AS. UBE3A deficiency and the hemizygosity of GABAaR genes could synergistically deteriorate neuronal function, resulting in aberrant SEFs in AS Del.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
| | - Naoko Asahina
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan
| | - Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan.
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Copping NA, Silverman JL. Abnormal electrophysiological phenotypes and sleep deficits in a mouse model of Angelman Syndrome. Mol Autism 2021; 12:9. [PMID: 33549123 PMCID: PMC7866697 DOI: 10.1186/s13229-021-00416-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/18/2021] [Indexed: 01/17/2023] Open
Abstract
Background Angelman Syndrome (AS) is a rare genetic disorder characterized by impaired communication, motor and balance deficits, intellectual disabilities, recurring seizures and abnormal sleep patterns. The genetic cause of AS is neuronal-specific loss of expression of UBE3A (ubiquitin-protein ligase E6-AP), an imprinted gene. Seizure and sleep disorders are highly prevalent (> 80%) in the AS population. The present experiments were designed to identify translational, neurophysiological outcome measures in a model of AS. Methods We used the exon-2 deletion mouse (Ube3a-del) on a C57BL/6J background to assess seizure, sleep and electrophysiological phenotypes. Seizure susceptibility has been reported in Ube3a-del mice with a variety of seizure induction methods. Here, we provoked seizures by a single high-dose injection of 80 mg/kg pentylenetetrazole. Novel experiments included the utilization of wireless telemetry devices to acquire global electroencephalogram (EEG) and neurophysiological data on electrographic seizures, power spectra, light–dark cycles, sleep stages and sleep spindles in Ube3a-del and WT mice. Results Ube3a-del mice exhibited reduced seizure threshold compared to WT. EEG illustrated that Ube3a-del mice had increased epileptiform spiking activity and delta power, which corroborates findings from other laboratories and recapitulates clinical reports in AS. This is the first report to use a cortical surface-based recording by a wireless telemetry device over tethered/fixed head-mount depth recordings. Less time in both paradoxical and slow-wave sleep, longer latencies to paradoxical sleep stages and total less sleep time in Ube3a-del mice were observed compared to WT. For the first time, we detected fewer sleep spindles in the AS mouse model. Limitations This study was limited to the exon 2 deletion mouse model, and future work will investigate the rat model of AS, containing a complete Ube3a deletion and pair EEG with behavior. Conclusions Our data enhance rigor and translatability as our study provides important corroboration of previous reports on epileptiform and elevated delta power. For the first time we report neurophysiological phenotypes collected via translational methodology. Furthermore, this is the first report of reduced sleep spindles, a critical marker of memory consolidation during sleep, in an AS model. Our results are useful outcomes for therapeutic testing.
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Affiliation(s)
- N A Copping
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001B, Research II Building 96, 4625 2nd Avenue, Sacramento, CA, 95817, USA
| | - J L Silverman
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Room 1001B, Research II Building 96, 4625 2nd Avenue, Sacramento, CA, 95817, USA.
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Cheffer A, Flitsch LJ, Krutenko T, Röderer P, Sokhranyaeva L, Iefremova V, Hajo M, Peitz M, Schwarz MK, Brüstle O. Human stem cell-based models for studying autism spectrum disorder-related neuronal dysfunction. Mol Autism 2020; 11:99. [PMID: 33308283 PMCID: PMC7733257 DOI: 10.1186/s13229-020-00383-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
The controlled differentiation of pluripotent stem cells (PSCs) into neurons and glia offers a unique opportunity to study early stages of human central nervous system development under controlled conditions in vitro. With the advent of cell reprogramming and the possibility to generate induced pluripotent stem cells (iPSCs) from any individual in a scalable manner, these studies can be extended to a disease- and patient-specific level. Autism spectrum disorder (ASD) is considered a neurodevelopmental disorder, with substantial evidence pointing to early alterations in neurogenesis and network formation as key pathogenic drivers. For that reason, ASD represents an ideal candidate for stem cell-based disease modeling. Here, we provide a concise review on recent advances in the field of human iPSC-based modeling of syndromic and non-syndromic forms of ASD, with a particular focus on studies addressing neuronal dysfunction and altered connectivity. We further discuss recent efforts to translate stem cell-based disease modeling to 3D via brain organoid and cell transplantation approaches, which enable the investigation of disease mechanisms in a tissue-like context. Finally, we describe advanced tools facilitating the assessment of altered neuronal function, comment on the relevance of iPSC-based models for the assessment of pharmaceutical therapies and outline potential future routes in stem cell-based ASD research.
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Affiliation(s)
- Arquimedes Cheffer
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Lea Jessica Flitsch
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Tamara Krutenko
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Pascal Röderer
- Life & Brain GmbH, Platform Cellomics, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Liubov Sokhranyaeva
- Institute of Experimental Epileptology and Cognition Research, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Vira Iefremova
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Mohamad Hajo
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Michael Peitz
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
- Life & Brain GmbH, Platform Cellomics, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
- Cell Programming Core Facility, University of Bonn Medical Faculty, Bonn, Germany
| | - Martin Karl Schwarz
- Life & Brain GmbH, Platform Cellomics, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
- Institute of Experimental Epileptology and Cognition Research, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Venusberg-Campus 1, Building 76, 53127, Bonn, Germany.
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Bartolini E, Campostrini R, Kiferle L, Pradella S, Rosati E, Chinthapalli K, Palumbo P. Epilepsy and brain channelopathies from infancy to adulthood. Neurol Sci 2019; 41:749-761. [PMID: 31838630 DOI: 10.1007/s10072-019-04190-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 12/06/2019] [Indexed: 01/04/2023]
Abstract
Genetic brain channelopathies result from inherited or de novo mutations of genes encoding ion channel subunits within the central nervous system. Most neurological channelopathies arise in childhood with paroxysmal or episodic symptoms, likely because of a transient impairment of homeostatic mechanisms regulating membrane excitability, and the prototypical expression of this impairment is epilepsy. Migraine, episodic ataxia and alternating hemiplegia can also occur, as well as chronic phenotypes, such as spinocerebellar ataxias, intellectual disability and autism spectrum disorder. Voltage-gated and ligand-gated channels may be involved. In most cases, a single gene may be associated with a phenotypical spectrum that shows variable expressivity. Different clinical features may arise at different ages and the adult phenotype may be remarkably modified from the syndrome onset in childhood or adolescence. Recognizing the prominent phenotypical traits of brain channelopathies is essential to perform appropriate diagnostic investigations and to provide the better care not only in the paediatric setting but also for adult patients and their caregivers. Herein, we provide an overview of genetic brain channelopathies associated with epilepsy, highlight the different molecular mechanisms and describe the different clinical characteristics which may prompt the clinician to suspect specific syndromes and to possibly establish tailored treatments.
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Affiliation(s)
- Emanuele Bartolini
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy.
| | - Roberto Campostrini
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Lorenzo Kiferle
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Silvia Pradella
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Eleonora Rosati
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | | | - Pasquale Palumbo
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
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Sequeira A, Shen K, Gottlieb A, Limon A. Human brain transcriptome analysis finds region- and subject-specific expression signatures of GABA AR subunits. Commun Biol 2019; 2:153. [PMID: 31069263 PMCID: PMC6494906 DOI: 10.1038/s42003-019-0413-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 04/03/2019] [Indexed: 11/19/2022] Open
Abstract
Altered expression of GABA receptors (GABAARs) has been implicated in neurological and psychiatric disorders, but limited information about region-specific GABAAR subunit expression in healthy human brains, heteromeric assembly of major isoforms, and their collective organization across healthy individuals, are major roadblocks to understanding their role in non-physiological states. Here, by using microarray and RNA-Seq datasets-from single cell nuclei to global brain expression-from the Allen Institute, we find that transcriptional expression of GABAAR subunits is anatomically organized according to their neurodevelopmental origin. The data show a combination of complementary and mutually-exclusive expression patterns that delineate major isoforms, and which is highly stereotypical across brains from control donors. We summarize the region-specific signature of GABAR subunits per subject and its variability in a control population sample that can be used as a reference for remodeling changes during homeostatic rearrangements of GABAAR subunits after physiological, pharmacological or pathological challenges.
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Affiliation(s)
- Adolfo Sequeira
- Department of Psychiatry and Human Behavior, School of Medicine, University of California Irvine, Irvine, CA USA
| | - Kevin Shen
- Department of Neurology, Mitchel Center for Neurodegenerative Diseases, School of Medicine, University of Texas Medical Branch, Galveston, TX USA
| | - Assaf Gottlieb
- School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX USA
| | - Agenor Limon
- Department of Neurology, Mitchel Center for Neurodegenerative Diseases, School of Medicine, University of Texas Medical Branch, Galveston, TX USA
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Frohlich J, Miller MT, Bird LM, Garces P, Purtell H, Hoener MC, Philpot BD, Sidorov MS, Tan WH, Hernandez MC, Rotenberg A, Jeste SS, Krishnan M, Khwaja O, Hipp JF. Electrophysiological Phenotype in Angelman Syndrome Differs Between Genotypes. Biol Psychiatry 2019; 85:752-759. [PMID: 30826071 PMCID: PMC6482952 DOI: 10.1016/j.biopsych.2019.01.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/11/2018] [Accepted: 01/04/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by either disruptions of the gene UBE3A or deletion of chromosome 15 at 15q11-q13, which encompasses UBE3A and several other genes, including GABRB3, GABRA5, GABRG3, encoding gamma-aminobutyric acid type A receptor subunits (β3, α5, γ3). Individuals with deletions are generally more impaired than those with other genotypes, but the underlying pathophysiology remains largely unknown. Here, we used electroencephalography (EEG) to test the hypothesis that genes other than UBE3A located on 15q11-q13 cause differences in pathophysiology between AS genotypes. METHODS We compared spectral power of clinical EEG recordings from children (1-18 years of age) with a deletion genotype (n = 37) or a nondeletion genotype (n = 21) and typically developing children without Angelman syndrome (n = 48). RESULTS We found elevated theta power (peak frequency: 5.3 Hz) and diminished beta power (peak frequency: 23 Hz) in the deletion genotype compared with the nondeletion genotype as well as excess broadband EEG power (1-32 Hz) peaking in the delta frequency range (peak frequency: 2.8 Hz), shared by both genotypes but stronger for the deletion genotype at younger ages. CONCLUSIONS Our results provide strong evidence for the contribution of non-UBE3A neuronal pathophysiology in deletion AS and suggest that hemizygosity of the GABRB3-GABRA5-GABRG3 gene cluster causes abnormal theta and beta EEG oscillations that may underlie the more severe clinical phenotype. Our work improves the understanding of AS pathophysiology and has direct implications for the development of AS treatments and biomarkers.
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Affiliation(s)
- Joel Frohlich
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland; Center for Autism Research and Treatment, Semel Institute for Neuroscience, University of California, Los Angeles, Los Angeles.
| | - Meghan T Miller
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland
| | - Lynne M Bird
- Department of Pediatrics, University of California, San Diego, Massachusetts; Division of Genetics/Dysmorphology, Rady Children's Hospital San Diego, San Diego, Massachusetts
| | - Pilar Garces
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland
| | - Hannah Purtell
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Marius C Hoener
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland
| | - Benjamin D Philpot
- Neuroscience Center, Carolina Institute for Developmental Disabilities, Chapel Hill, North Carolina; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Michael S Sidorov
- Neuroscience Center, Carolina Institute for Developmental Disabilities, Chapel Hill, North Carolina; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Wen-Hann Tan
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Maria-Clemencia Hernandez
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shafali S Jeste
- Center for Autism Research and Treatment, Semel Institute for Neuroscience, University of California, Los Angeles, Los Angeles
| | - Michelle Krishnan
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland
| | - Omar Khwaja
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland
| | - Joerg F Hipp
- Neuroscience, Ophthalmology and Rare Diseases, Roche Innovation Center, Roche Pharma Research and Early Development, Basel, Switzerland.
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Brueggeman L, Sturgeon ML, Martin RM, Grossbach AJ, Nagahama Y, Zhang A, Howard MA, Kawasaki H, Wu S, Cornell RA, Michaelson JJ, Bassuk AG. Drug repositioning in epilepsy reveals novel antiseizure candidates. Ann Clin Transl Neurol 2019; 6:295-309. [PMID: 30847362 PMCID: PMC6389756 DOI: 10.1002/acn3.703] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 01/22/2023] Open
Abstract
Objective Epilepsy treatment falls short in ~30% of cases. A better understanding of epilepsy pathophysiology can guide rational drug development in this difficult to treat condition. We tested a low-cost, drug-repositioning strategy to identify candidate epilepsy drugs that are already FDA-approved and might be immediately tested in epilepsy patients who require new therapies. Methods Biopsies of spiking and nonspiking hippocampal brain tissue from six patients with unilateral mesial temporal lobe epilepsy were analyzed by RNA-Seq. These profiles were correlated with transcriptomes from cell lines treated with FDA-approved drugs, identifying compounds which were tested for therapeutic efficacy in a zebrafish seizure assay. Results In spiking versus nonspiking biopsies, RNA-Seq identified 689 differentially expressed genes, 148 of which were previously cited in articles mentioning seizures or epilepsy. Differentially expressed genes were highly enriched for protein-protein interactions and formed three clusters with associated GO-terms including myelination, protein ubiquitination, and neuronal migration. Among the 184 compounds, a zebrafish seizure model tested the therapeutic efficacy of doxycycline, metformin, nifedipine, and pyrantel tartrate, with metformin, nifedipine, and pyrantel tartrate all showing efficacy. Interpretation This proof-of-principle analysis suggests our powerful, rapid, cost-effective approach can likely be applied to other hard-to-treat diseases.
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Affiliation(s)
- Leo Brueggeman
- Department of PsychiatryCarver College of MedicineUniversity of IowaIowa CityIowa
| | - Morgan L. Sturgeon
- The Interdisciplinary Graduate Program in Molecular MedicineCarver College of MedicineUniversity of IowaIowa CityIowa
| | | | | | | | - Angela Zhang
- Department of BiostatisticsUniversity of WashingtonSeattleWashington
| | | | | | - Shu Wu
- Department of PediatricsUniversity of IowaIowa CityIowa
| | - Robert A. Cornell
- Department of Anatomy and Cell BiologyUniversity of IowaIowa CityIowa
| | - Jacob J. Michaelson
- Department of PsychiatryCarver College of MedicineUniversity of IowaIowa CityIowa
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Zwart R, Mazzo F, Sher E. Microtransplantation of human brain receptors into oocytes to tackle key questions in drug discovery. Drug Discov Today 2018; 24:533-543. [PMID: 30395928 DOI: 10.1016/j.drudis.2018.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/18/2018] [Accepted: 10/30/2018] [Indexed: 10/27/2022]
Abstract
It is important in drug discovery to demonstrate that activity of novel drugs found by screening on recombinant receptors translates to activity on native human receptors in brain areas affected by disease. In this review, we summarise the development and use of the microtransplantation technique. Native receptors are reconstituted from human brain tissues into oocytes from the frog Xenopus laevis where they can be functionally assessed. Oocytes microtransplanted with hippocampal tissue from an epileptic patient were used to demonstrate that new antiepileptic agents act on receptors in diseased tissue. Furthermore, frozen post-mortem human tissues were used to show that drugs are active on receptors in brain areas associated with a disease; but not in areas associated with side effects.
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Affiliation(s)
- Ruud Zwart
- Eli Lilly, Lilly Research Centre, Erl Wood Manor, Sunninghill Road, Windlesham, GU20 6PH, UK.
| | - Francesca Mazzo
- Eli Lilly, Lilly Research Centre, Erl Wood Manor, Sunninghill Road, Windlesham, GU20 6PH, UK
| | - Emanuele Sher
- Eli Lilly, Lilly Research Centre, Erl Wood Manor, Sunninghill Road, Windlesham, GU20 6PH, UK
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10
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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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11
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Salvati KA, Beenhakker MP. Out of thin air: Hyperventilation-triggered seizures. Brain Res 2017; 1703:41-52. [PMID: 29288644 DOI: 10.1016/j.brainres.2017.12.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/29/2017] [Accepted: 12/27/2017] [Indexed: 12/11/2022]
Abstract
Voluntary hyperventilation triggers seizures in the vast majority of people with absence epilepsy. The mechanisms that underlie this phenomenon remain unknown. Herein, we review observations - many made long ago - that provide insight into the relationship between breathing and absence seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22903, United States.
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12
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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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13
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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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14
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Blackmer AB, Feinstein JA. Management of Sleep Disorders in Children With Neurodevelopmental Disorders: A Review. Pharmacotherapy 2016; 36:84-98. [PMID: 26799351 DOI: 10.1002/phar.1686] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neurodevelopmental disorders (NDDs) are defined as a group of disorders caused by changes in early brain development, resulting in behavioral and cognitive alterations in sensory and motor systems, speech, and language. NDDs affect approximately 1-2% of the general population. Up to 80% of children with NDDs are reported to have disrupted sleep; subsequent deleterious effects on daytime behaviors, cognition, growth, and overall development of the child are commonly reported. Examples of NDDs discussed in this review include autism spectrum disorder, cerebral palsy, Rett syndrome, Angelman syndrome, Williams syndrome, and Smith-Magenis syndrome. The etiology of sleep disorders in children with NDDs is largely heterogeneous and disease specific. The diagnosis and management of sleep disorders in this population are complex, and little high-quality data exist to guide a consistent approach to therapy. Managing sleep disorders in children with NDDs is critical both for the child and for the family but is often frustrating due to the refractory nature of the problem. Sleep hygiene must be implemented as first-line therapy; if sleep hygiene alone fails, it should be combined with pharmacologic management. The available evidence for the use of common pharmacologic interventions, such as iron supplementation and melatonin, as well as less common interventions, such as melatonin receptor agonists, clonidine, gabapentin, hypnotics, trazodone, and atypical antipsychotics is reviewed. Further, parents and caregivers should be provided with appropriate education on the nature of the sleep disorders and the expectation for modest pharmacologic benefit, at best. Additional data from well-designed trials in children with NDDs are desperately needed to gain a better understanding of sleep pharmacotherapy including efficacy and safety implications. Until then, clinicians must rely on the limited available data, as well as clinical expertise, when managing sleep disorders in the population of children with NDDs.
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Affiliation(s)
- Allison Beck Blackmer
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, Colorado.,Department of Pharmacy/Special Care Clinic, Children's Hospital Colorado, Aurora, Colorado
| | - James A Feinstein
- Adult and Child Center for Health Outcomes Research and Delivery Science, Children's Hospital Colorado, Aurora, Colorado.,Division of General Pediatrics, University of Colorado, Aurora, Colorado
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15
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Seizure treatment in Angelman syndrome: A case series from the Angelman Syndrome Clinic at Massachusetts General Hospital. Epilepsy Behav 2016; 60:138-141. [PMID: 27206232 DOI: 10.1016/j.yebeh.2016.04.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/13/2016] [Accepted: 04/18/2016] [Indexed: 02/01/2023]
Abstract
Epilepsy is a common feature of Angelman syndrome (~80-90%), with the most common seizure types including myoclonic, atonic, atypical absence, focal, and generalized tonic-clonic. Seizure types are similar among the various genetic subtypes, but epilepsy in those with maternal deletions is more frequent and more refractory to medication. Treatment with older antiepileptic drugs such as valproic acid and clonazepam is effective, but these medications tend to have less favorable side effect profiles in Angelman syndrome compared with those in newer medications. This study aimed to assess the use of newer antiepileptic drug therapies in individuals with Angelman syndrome followed at the Angelman Syndrome Clinic at the Massachusetts General Hospital. Many of the subjects in this study were on valproic acid therapy prior to their initial evaluation and exhibited increased tremor, decreased balance, and/or regression of motor skills, which resolved after tapering off of this medication. Newer antiepileptic drugs such as levetiracetam, lamotrigine, and clobazam, and to a lesser extent topiramate, appeared to be as effective - if not more so - as valproic acid and clonazepam while offering more favorable side effect profiles. The low glycemic index treatment also provided effective seizure control with minimal side effects. The majority of subjects remained on combination therapy with levetiracetam, lamotrigine, and clobazam being the most commonly used medications, indicating a changing trend when compared with prior studies.
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16
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Adams DS, Uzel SGM, Akagi J, Wlodkowic D, Andreeva V, Yelick PC, Devitt-Lee A, Pare JF, Levin M. Bioelectric signalling via potassium channels: a mechanism for craniofacial dysmorphogenesis in KCNJ2-associated Andersen-Tawil Syndrome. J Physiol 2016; 594:3245-70. [PMID: 26864374 PMCID: PMC4908029 DOI: 10.1113/jp271930] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/01/2016] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Xenopus laevis craniofacial development is a good system for the study of Andersen-Tawil Syndrome (ATS)-associated craniofacial anomalies (CFAs) because (1) Kcnj2 is expressed in the nascent face; (2) molecular-genetic and biophysical techniques are available for the study of ion-dependent signalling during craniofacial morphogenesis; (3) as in humans, expression of variant Kcnj2 forms in embryos causes a muscle phenotype; and (4) variant forms of Kcnj2 found in human patients, when injected into frog embryos, cause CFAs in the same cell lineages. Forced expression of WT or variant Kcnj2 changes the normal pattern of Vmem (resting potential) regionalization found in the ectoderm of neurulating embryos, and changes the normal pattern of expression of ten different genetic regulators of craniofacial development, including markers of cranial neural crest and of placodes. Expression of other potassium channels and two different light-activated channels, all of which have an effect on Vmem , causes CFAs like those induced by injection of Kcnj2 variants. In contrast, expression of Slc9A (NHE3), an electroneutral ion channel, and of GlyR, an inactive Cl(-) channel, do not cause CFAs, demonstrating that correct craniofacial development depends on a pattern of bioelectric states, not on ion- or channel-specific signalling. Using optogenetics to control both the location and the timing of ion flux in developing embryos, we show that affecting Vmem of the ectoderm and no other cell layers is sufficient to cause CFAs, but only during early neurula stages. Changes in Vmem induced late in neurulation do not affect craniofacial development. We interpret these data as strong evidence, consistent with our hypothesis, that ATS-associated CFAs are caused by the effect of variant Kcnj2 on the Vmem of ectodermal cells of the developing face. We predict that the critical time is early during neurulation, and the critical cells are the ectodermal cranial neural crest and placode lineages. This points to the potential utility of extant, ion flux-modifying drugs as treatments to prevent CFAs associated with channelopathies such as ATS. ABSTRACT Variants in potassium channel KCNJ2 cause Andersen-Tawil Syndrome (ATS); the induced craniofacial anomalies (CFAs) are entirely unexplained. We show that KCNJ2 is expressed in Xenopus and mouse during the earliest stages of craniofacial development. Misexpression in Xenopus of KCNJ2 carrying ATS-associated mutations causes CFAs in the same structures affected in humans, changes the normal pattern of membrane voltage potential regionalization in the developing face and disrupts expression of important craniofacial patterning genes, revealing the endogenous control of craniofacial patterning by bioelectric cell states. By altering cells' resting potentials using other ion translocators, we show that a change in ectodermal voltage, not tied to a specific protein or ion, is sufficient to cause CFAs. By adapting optogenetics for use in non-neural cells in embryos, we show that developmentally patterned K(+) flux is required for correct regionalization of the resting potentials and for establishment of endogenous early gene expression domains in the anterior ectoderm, and that variants in KCNJ2 disrupt this regionalization, leading to the CFAs seen in ATS patients.
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Affiliation(s)
- Dany Spencer Adams
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
| | - Sebastien G M Uzel
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Jin Akagi
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Donald Wlodkowic
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Viktoria Andreeva
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University School of Dental Medicine, Boston, MA 02111, USA
| | - Pamela Crotty Yelick
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University School of Dental Medicine, Boston, MA 02111, USA
| | - Adrian Devitt-Lee
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
| | - Jean-Francois Pare
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
| | - Michael Levin
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
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17
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Bittolo T, Raminelli CA, Deiana C, Baj G, Vaghi V, Ferrazzo S, Bernareggi A, Tongiorgi E. Pharmacological treatment with mirtazapine rescues cortical atrophy and respiratory deficits in MeCP2 null mice. Sci Rep 2016; 6:19796. [PMID: 26806603 PMCID: PMC4726391 DOI: 10.1038/srep19796] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/14/2015] [Indexed: 01/22/2023] Open
Abstract
Loss of MeCP2 (Methyl CpG binding protein 2) in Rett syndrome (RTT) causes brain weight decrease, shrinkage of the cortex with reduced dendritic arborization, behavioral abnormalities, seizures and cardio-respiratory complications. The observed monoamine neurotransmitters reduction in RTT suggested antidepressants as a possible therapy. We treated MeCP2-null mice from postnatal-day 28 for two weeks with desipramine, already tested in RTT, or mirtazapine, an antidepressant with limited side-effects, known to promote GABA release. Mirtazapine was more effective than desipramine in restoring somatosensory cortex thickness by fully rescuing pyramidal neurons dendritic arborization and spine density. Functionally, mirtazapine treatment normalized heart rate, breath rate, anxiety levels, and eliminated the hopping behavior observed in MeCP2-null mice, leading to improved phenotypic score. These morphological and functional effects of mirtazapine were accompanied by reestablishment of the GABAergic and glutamatergic receptor activity recorded in cortex and brainstem tissues. Thus, mirtazapine can represent a new potential pharmacological treatment for the Rett syndrome.
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Affiliation(s)
- Tamara Bittolo
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Carlo Antonio Raminelli
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Chiara Deiana
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Gabriele Baj
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Valentina Vaghi
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Sara Ferrazzo
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Annalisa Bernareggi
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
| | - Enrico Tongiorgi
- Department of Life Sciences, University of Trieste, Via L. Giorgieri, 5-34127 Trieste, Italy
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18
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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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19
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Perioperative considerations in the patient with Angelman syndrome. J Clin Anesth 2014; 26:75-9. [PMID: 24440034 DOI: 10.1016/j.jclinane.2013.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 07/03/2013] [Accepted: 07/14/2013] [Indexed: 11/22/2022]
Abstract
Angelman syndrome arises by one of 4 genetic mechanisms. Patients often have craniofacial abnormalities, vagal hypertonia, skeletal muscle atrophy or underdevelopment, a history of seizure disorders, and pharmacodynamic unpredictability. Its pathogenesis, clinical manifestations, diagnosis and treatment options, and perioperative anesthetic considerations are presented.
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20
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Levin M. Reprogramming cells and tissue patterning via bioelectrical pathways: molecular mechanisms and biomedical opportunities. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2013; 5:657-76. [PMID: 23897652 PMCID: PMC3841289 DOI: 10.1002/wsbm.1236] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/16/2013] [Accepted: 06/21/2013] [Indexed: 12/17/2022]
Abstract
Transformative impact in regenerative medicine requires more than the reprogramming of individual cells: advances in repair strategies for birth defects or injuries, tumor normalization, and the construction of bioengineered organs and tissues all require the ability to control large-scale anatomical shape. Much recent work has focused on the transcriptional and biochemical regulation of cell behavior and morphogenesis. However, exciting new data reveal that bioelectrical properties of cells and their microenvironment exert a profound influence on cell differentiation, proliferation, and migration. Ion channels and pumps expressed in all cells, not just excitable nerve and muscle, establish resting potentials that vary across tissues and change with significant developmental events. Most importantly, the spatiotemporal gradients of these endogenous transmembrane voltage potentials (Vmem ) serve as instructive patterning cues for large-scale anatomy, providing organ identity, positional information, and prepattern template cues for morphogenesis. New genetic and pharmacological techniques for molecular modulation of bioelectric gradients in vivo have revealed the ability to initiate complex organogenesis, change tissue identity, and trigger regeneration of whole vertebrate appendages. A large segment of the spatial information processing that orchestrates individual cells' programs toward the anatomical needs of the host organism is electrical; this blurs the line between memory and decision-making in neural networks and morphogenesis in nonneural tissues. Advances in cracking this bioelectric code will enable the rational reprogramming of shape in whole tissues and organs, revolutionizing regenerative medicine, developmental biology, and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Tufts University, Department of Biology and Tufts Center for Regenerative and Developmental Biology, 200 Boston Ave., Suite 4600, Medford, MA 02155
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21
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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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22
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Impairment of cortical GABAergic synaptic transmission in an environmental rat model of autism. Int J Neuropsychopharmacol 2013; 16:1309-18. [PMID: 23228615 PMCID: PMC3674140 DOI: 10.1017/s1461145712001216] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The biological mechanisms of autism spectrum disorders (ASDs) are largely unknown in spite of extensive research. ASD is characterized by altered function of multiple brain areas including the temporal cortex and by an increased synaptic excitation:inhibition ratio. While numerous studies searched for evidence of increased excitation in ASD, fewer have investigated the possibility of reduced inhibition. We characterized the cortical γ-amino butyric acid (GABA)ergic system in the rat temporal cortex of an ASD model [offspring of mothers prenatally injected with valproic acid (VPA)], by monitoring inhibitory post-synaptic currents (IPSCs) with patch-clamp. We found that numerous features of inhibition were severely altered in VPA animals compared to controls. Among them were the frequency of miniature IPSCs, the rise time and decay time of electrically-evoked IPSCs, the slope and saturation of their input/output curves, as well as their modulation by adrenergic and muscarinic agonists and by the synaptic GABAA receptor allosteric modulator zolpidem (but not by the extra-synaptic modulator gaboxadol). Our data suggest that both pre- and post-synaptic, but not extra-synaptic, inhibitory transmission is impaired in the offspring of VPA-injected mothers. We speculate that impairment in the GABAergic system critically contributes to an increase in the ratio between synaptic excitation and inhibition, which in genetically predisposed individuals may alter cortical circuits responsible for emotional, communication and social impairments at the core of ASD.
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Egawa K, Kitagawa K, Inoue K, Takayama M, Takayama C, Saitoh S, Kishino T, Kitagawa M, Fukuda A. Decreased tonic inhibition in cerebellar granule cells causes motor dysfunction in a mouse model of Angelman syndrome. Sci Transl Med 2013; 4:163ra157. [PMID: 23220633 DOI: 10.1126/scitranslmed.3004655] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Angelman syndrome is a neurodevelopmental disorder caused by loss of function of the UBE3A gene encoding a ubiquitin E3 ligase. Motor dysfunction is a characteristic feature of Angelman syndrome, but neither the mechanisms of action nor effective therapeutic strategies have yet been elucidated. We report that tonic inhibition is specifically decreased in cerebellar granule cells of Ube3a-deficient mice, a model of Angelman syndrome. As a mechanism underlying this decrease in tonic inhibition, we show that Ube3a controls degradation of γ-aminobutyric acid (GABA) transporter 1 (GAT1) and that deficiency of Ube3a induces a surplus of GAT1 that results in a decrease in GABA concentrations in the extrasynaptic space. Administering low doses of 4,5,6,7-tetrahydroisothiazolo-[5,4-c]pyridin-3-ol (THIP), a selective extrasynaptic GABA(A) receptor agonist, improves the abnormal firing properties of a population of Purkinje cells in cerebellar brain slices and reduces cerebellar ataxia in Ube3a-deficient mice in vivo. These results suggest that pharmacologically increasing tonic inhibition may be a useful strategy for alleviating motor dysfunction in Angelman syndrome.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
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Leung HTT, Ring H. Epilepsy in four genetically determined syndromes of intellectual disability. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2013; 57:3-20. [PMID: 22142420 DOI: 10.1111/j.1365-2788.2011.01505.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND Epilepsy occurs with increased frequency in people with an intellectual disability (ID) compared to the rest of the population. A variety of research has in recent years shed light on genetic and biochemical aetiologies of epilepsy and, often in a different literature, on syndromes of ID. The aims of this annotation are to review developments in understanding of the pathophysiology of several ID syndromes in which epilepsy is a frequent co-occurrence and to relate these observations to recent advances in understanding of how these pathophysiological disturbances may lead to epilepsy. METHOD The ID syndromes selected for review were fragile X (FXS), Rett (RTT) and Angelman syndromes (AS) and tuberous sclerosis complex (TSC). Epilepsy is a significant aspect of these syndromes and relevant research into the genetic and biochemical pathophysiology of these four ID syndromes may be informative in establishing the association between epilepsy and ID. Employing a structured approach the authors initially searched the PubMed database for large case series describing the characteristics of epilepsy as manifested in these ID syndromes. The criteria for inclusion of the case series in the review were a sample size of greater than 50 and the description of several of the characteristic features of epilepsy, namely prevalence of seizures, age of seizure onset, seizure frequency, seizure semiology, severity and treatment. Following this, studies of the genetic and biochemical pathophysiology of these four ID syndromes were reviewed and the potential relevance of this research in understanding the association with epilepsy highlighted. Findings were considered in a focused manner in terms of effects on excitatory and inhibitory neurotransmitter systems and on glial function. RESULTS Diverse genetic pathologies underlying several ID syndromes can lead to alterations in the functioning of the glutamatergic and GABAergic neurotransmitter systems. The mechanisms involved include transcriptional regulation in RTT, translational regulation in FXS and TSC, and UBE3A-mediated proteolysis in AS. Expression or functioning of receptor subunits, uptake sites and enzymes involved in neurotransmitter metabolism are often affected by these changes, and may lead to modifications in network excitability and neuronal plasticity that may contribute to epileptogenesis and ID. Dysfunction in astrocytes may also contribute to epileptogenesis and ID in FXS, RTT and TSC with potential mechanisms including failure of astrocytic support functions, glial inflammation and homeostatic disturbances that affect the excitability and architecture of neuronal networks. CONCLUSIONS The annotation highlights research describing disturbances in excitatory and inhibitory neurotransmitter systems, neuronal ion channel and glial functions that provide possible explanations for the co-occurrence of seizures within several ID syndromes, in some cases suggesting possible avenues for research into novel therapeutic targets. Phenotypic overlaps between syndromes may also relate to roles for the implicated genes in different disturbances in linked biochemical pathways.
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Affiliation(s)
- H T T Leung
- Christ's College, University of Cambridge, UK
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Loss of functional GABA(A) receptors in the Alzheimer diseased brain. Proc Natl Acad Sci U S A 2012; 109:10071-6. [PMID: 22691495 DOI: 10.1073/pnas.1204606109] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cholinergic and glutamatergic neurotransmission systems are known to be severely disrupted in Alzheimer's disease (AD). GABAergic neurotransmission, in contrast, is generally thought to be well preserved. Evidence from animal models and human postmortem tissue suggest GABAergic remodeling in the AD brain. Nevertheless, there is no information on changes, if any, in the electrophysiological properties of human native GABA receptors as a consequence of AD. To gain such information, we have microtransplanted cell membranes, isolated from temporal cortices of control and AD brains, into Xenopus oocytes, and recorded the electrophysiological activity of the transplanted GABA receptors. We found an age-dependent reduction of GABA currents in the AD brain. This reduction was larger when the AD membranes were obtained from younger subjects. We also found that GABA currents from AD brains have a faster rate of desensitization than those from non-AD brains. Furthermore, GABA receptors from AD brains were slightly, but significantly, less sensitive to GABA than receptors from non-AD brains. The reduction of GABA currents in AD was associated with reductions of mRNA and protein of the principal GABA receptor subunits normally present in the temporal cortex. Pairwise analysis of the transcripts within control and AD groups and analyses of the proportion of GABA receptor subunits revealed down-regulation of α1 and γ2 subunits in AD. In contrast, the proportions of α2, β1, and γ1 transcripts were up-regulated in the AD brains. Our data support a functional remodeling of GABAergic neurotransmission in the human AD brain.
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Landsman IS, Mitzel HM, Peters SU, Bichell TJ. Are children with Angelman syndrome at high risk for anesthetic complications? Paediatr Anaesth 2012; 22:263-7. [PMID: 21801274 DOI: 10.1111/j.1460-9592.2011.03661.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES/AIMS To review seven children with Angelman syndrome (AS) undergoing 16 general anesthetics for both invasive and noninvasive procedures to determine if these children are at greater risk for anesthetic-related complications than the general population. BACKGROUND Children with AS may exhibit unpredictable responses to GABA agonists because of abnormal GABA receptors. These abnormal receptors may affect AS patients' responses to sedation and general anesthesia. METHODS The study design was a retrospective chart review of seven patients with AS who underwent a total of 16 general anesthetics for a variety of invasive and noninvasive procedures between the years 4/25/2005 and 12/31/2010. We reviewed the preoperative orders, anesthesia record and PACU records for preoperative medication orders and intraoperative and PACU adverse events. RESULTS We could not find documentation of complications attributed to the delivery of general anesthesia regardless of chromosomal defect, the use of GABA activating drugs, or a history of seizures. Six patients received a propofol-based anesthetic while 10 patients received potent inhalation agent for anesthetic maintenance. There were no statistical differences between the PACU lengths of stay (LOS) for AS patients as compared to the average PACU LOS for the 60 969 postprocedure patients cared for between 1/1/06 through 12/31/10. CONCLUSIONS We found no data to suggest that these patients demonstrate exaggerated responses to GABA stimulating drugs. In fact, it appears that regardless of the anesthetic agent, the perioperative course was unremarkable.
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Affiliation(s)
- Ira S Landsman
- Anesthesiology and Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA.
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LeBlanc JJ, Fagiolini M. Autism: a "critical period" disorder? Neural Plast 2011; 2011:921680. [PMID: 21826280 PMCID: PMC3150222 DOI: 10.1155/2011/921680] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 06/02/2011] [Indexed: 11/24/2022] Open
Abstract
Cortical circuits in the brain are refined by experience during critical periods early in postnatal life. Critical periods are regulated by the balance of excitatory and inhibitory (E/I) neurotransmission in the brain during development. There is now increasing evidence of E/I imbalance in autism, a complex genetic neurodevelopmental disorder diagnosed by abnormal socialization, impaired communication, and repetitive behaviors or restricted interests. The underlying cause is still largely unknown and there is no fully effective treatment or cure. We propose that alteration of the expression and/or timing of critical period circuit refinement in primary sensory brain areas may significantly contribute to autistic phenotypes, including cognitive and behavioral impairments. Dissection of the cellular and molecular mechanisms governing well-established critical periods represents a powerful tool to identify new potential therapeutic targets to restore normal plasticity and function in affected neuronal circuits.
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Affiliation(s)
- Jocelyn J. LeBlanc
- Harvard Medical School and The F. M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, MA 02115, USA
| | - Michela Fagiolini
- Harvard Medical School and The F. M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, MA 02115, USA
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