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Picrotoxin Delineates Different Transport Configurations for Malate and γ Aminobutyric Acid through TaALMT1. BIOLOGY 2022; 11:biology11081162. [PMID: 36009788 PMCID: PMC9405015 DOI: 10.3390/biology11081162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/11/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022]
Abstract
Plant-derived pharmacological agents have been used extensively to dissect the structure–function relationships of mammalian GABA receptors and ion channels. Picrotoxin is a non-competitive antagonist of mammalian GABAA receptors. Here, we report that picrotoxin inhibits the anion (malate) efflux mediated by wheat (Triticum aestivum) ALMT1 but has no effect on GABA transport. The EC50 for inhibition was 0.14 nM and 0.18 nM when the ALMTs were expressed in tobacco BY2 cells and in Xenopus oocytes, respectively. Patch clamping of the oocyte plasma membrane expressing wheat ALMT1 showed that picrotoxin inhibited malate currents from both sides of the membrane. These results demonstrate that picrotoxin inhibits anion efflux effectively and can be used as a new inhibitor to study the ion fluxes mediated by ALMT proteins that allow either GABA or anion transport.
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2
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Michalettos G, Ruscher K. Crosstalk Between GABAergic Neurotransmission and Inflammatory Cascades in the Post-ischemic Brain: Relevance for Stroke Recovery. Front Cell Neurosci 2022; 16:807911. [PMID: 35401118 PMCID: PMC8983863 DOI: 10.3389/fncel.2022.807911] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/28/2022] [Indexed: 11/28/2022] Open
Abstract
Adaptive plasticity processes are required involving neurons as well as non-neuronal cells to recover lost brain functions after an ischemic stroke. Recent studies show that gamma-Aminobutyric acid (GABA) has profound effects on glial and immune cell functions in addition to its inhibitory actions on neuronal circuits in the post-ischemic brain. Here, we provide an overview of how GABAergic neurotransmission changes during the first weeks after stroke and how GABA affects functions of astroglial and microglial cells as well as peripheral immune cell populations accumulating in the ischemic territory and brain regions remote to the lesion. Moreover, we will summarize recent studies providing data on the immunomodulatory actions of GABA of relevance for stroke recovery. Interestingly, the activation of GABA receptors on immune cells exerts a downregulation of detrimental anti-inflammatory cascades. Conversely, we will discuss studies addressing how specific inflammatory cascades affect GABAergic neurotransmission on the level of GABA receptor composition, GABA synthesis, and release. In particular, the chemokines CXCR4 and CX3CR1 pathways have been demonstrated to modulate receptor composition and synthesis. Together, the actual view on the interactions between GABAergic neurotransmission and inflammatory cascades points towards a specific crosstalk in the post-ischemic brain. Similar to what has been shown in experimental models, specific therapeutic modulation of GABAergic neurotransmission and inflammatory pathways may synergistically promote neuronal plasticity to enhance stroke recovery.
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Affiliation(s)
- Georgios Michalettos
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Karsten Ruscher
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
- LUBIN Lab—Lunds Laboratorium för Neurokirurgisk Hjärnskadeforskning, Division of Neurosurgery, Department of Clinical Sciences, Lund University, Lund, Sweden
- *Correspondence: Karsten Ruscher
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3
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Shimizu-Okabe C, Kobayashi S, Kim J, Kosaka Y, Sunagawa M, Okabe A, Takayama C. Developmental Formation of the GABAergic and Glycinergic Networks in the Mouse Spinal Cord. Int J Mol Sci 2022; 23:ijms23020834. [PMID: 35055019 PMCID: PMC8776010 DOI: 10.3390/ijms23020834] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 12/15/2022] Open
Abstract
Gamma-aminobutyric acid (GABA) and glycine act as inhibitory neurotransmitters. Three types of inhibitory neurons and terminals, GABAergic, GABA/glycine coreleasing, and glycinergic, are orchestrated in the spinal cord neural circuits and play critical roles in regulating pain, locomotive movement, and respiratory rhythms. In this study, we first describe GABAergic and glycinergic transmission and inhibitory networks, consisting of three types of terminals in the mature mouse spinal cord. Second, we describe the developmental formation of GABAergic and glycinergic networks, with a specific focus on the differentiation of neurons, formation of synapses, maturation of removal systems, and changes in their action. GABAergic and glycinergic neurons are derived from the same domains of the ventricular zone. Initially, GABAergic neurons are differentiated, and their axons form synapses. Some of these neurons remain GABAergic in lamina I and II. Many GABAergic neurons convert to a coreleasing state. The coreleasing neurons and terminals remain in the dorsal horn, whereas many ultimately become glycinergic in the ventral horn. During the development of terminals and the transformation from radial glia to astrocytes, GABA and glycine receptor subunit compositions markedly change, removal systems mature, and GABAergic and glycinergic action shifts from excitatory to inhibitory.
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Affiliation(s)
- Chigusa Shimizu-Okabe
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Shiori Kobayashi
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Jeongtae Kim
- Department of Anatomy, Kosin University College of Medicine, Busan 49267, Korea;
| | - Yoshinori Kosaka
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Masanobu Sunagawa
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Akihito Okabe
- Department of Nutritional Science, Faculty of Health and Welfare, Seinan Jo Gakuin University, Fukuoka 803-0835, Japan;
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
- Correspondence: ; Tel.: +81-98-895-1103 or +81-895-1405
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4
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Nayeri T, Sarvi S, Daryani A. Toxoplasmosis: Targeting neurotransmitter systems in psychiatric disorders. Metab Brain Dis 2022; 37:123-146. [PMID: 34476718 DOI: 10.1007/s11011-021-00824-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/14/2021] [Indexed: 12/30/2022]
Abstract
The most common form of the disease caused by Toxoplasma gondii (T. gondii) is latent toxoplasmosis due to the formation of tissue cysts in various organs, such as the brain. Latent toxoplasmosis is probably a risk factor in the development of some neuropsychiatric disorders. Behavioral changes after infection are caused by the host immune response, manipulation by the parasite, central nervous system (CNS) inflammation, as well as changes in hormonal and neuromodulator relationships. The present review focused on the exact mechanisms of T. gondii effect on the alteration of behavior and neurotransmitter levels, their catabolites and metabolites, as well as the interaction between immune responses and this parasite in the etiopathogenesis of psychiatric disorders. The dysfunction of neurotransmitters in the neural transmission is associated with several neuropsychiatric disorders. However, further intensive studies are required to determine the effect of this parasite on altering the level of neurotransmitters and the role of neurotransmitters in the etiology of host behavioral changes.
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Affiliation(s)
- Tooran Nayeri
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
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5
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GAD67-mediated GABA Synthesis and Signaling Impinges on Directing Basket Cell Axonal Projections Toward Purkinje Cells in the Cerebellum. THE CEREBELLUM 2021; 21:905-919. [PMID: 34676525 DOI: 10.1007/s12311-021-01334-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the central nervous system, synthesized by two isoforms of glutamate decarboxylase (GAD): GAD65 and GAD67. GABA may act as a trophic factor during brain development, but its contribution to the development and maturation of cerebellar neural circuits is not known. To understand the roles of GABA in cerebellar organization and associated functions in motor coordination and balance, we examined GAD65 conventional knock out (KO) mice and mice in which GAD67 was eliminated in parvalbumin-expressing neurons (PV-Cre; GAD67flox/flox mice). We found aberrant subcellular localization of the Shaker-type K channel Kv1.1 in basket cell collaterals of PV-Cre; GAD67 flox/flox mice and abnormal projections from basket cells to Purkinje cells in both mouse strains. We also found that altered synaptic properties of basket cell terminals to Purkinje cells in PV-Cre; GAD67flox/flox mice. Furthermore, PV-Cre; GAD67 flox/flox mice exhibited abnormal motor coordination in the rotarod test. These results indicate that GABA signaling in the cerebellum is critical for establishing appropriate connections between basket cells and Purkinje cells and is associated with motor coordination in mice.
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6
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Panthi S, Lyons NMA, Leitch B. Impact of Dysfunctional Feed-Forward Inhibition on Glutamate Decarboxylase Isoforms and γ-Aminobutyric Acid Transporters. Int J Mol Sci 2021; 22:ijms22147740. [PMID: 34299369 PMCID: PMC8306481 DOI: 10.3390/ijms22147740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/16/2021] [Indexed: 12/02/2022] Open
Abstract
Absence seizures are associated with generalised synchronous 2.5–4 Hz spike-wave discharges causing brief and sudden alteration of awareness during childhood, which is known as childhood absence epilepsy (CAE). CAE is also associated with impaired learning, psychosocial challenges, and physical danger. Absence seizures arise from disturbances within the cortico-thalamocortical (CTC) network, including dysfunctional feed-forward inhibition (FFI); however, the precise mechanisms remain unclear. In epileptic stargazers, a genetic mouse model of CAE with chronic seizures, levels of γ-aminobutyric acid (GABA), and expression of GABA receptors are altered within the CTC network, implicating altered GABAergic transmission in absence seizures. However, the expression of GABA synthesising enzymes (GAD65 and GAD67) and GABA transporters (GAT-1 and 3) have not yet been characterised within absence seizure models. We found a specific upregulation of GAD65 in the somatosensory cortex but not the thalamus of epileptic stargazer mice. No differences were detected in GAD67 and GAT-3 levels in the thalamus or somatosensory cortex. Then, we assessed if GAD65 upregulation also occurred in Gi-DREADD mice exhibiting acute absence seizures, but we found no change in the expression profiles of GAD65/67 or GAT-3. Thus, the upregulation of GAD65 in stargazers may be a compensatory mechanism in response to long-term dysfunctional FFI and chronic absence seizures.
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Affiliation(s)
| | | | - Beulah Leitch
- Correspondence: ; Tel.: +64-3-479-7618; Fax: +64-3-479-7254
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7
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Kogure M, Kanahara N, Miyazawa A, Oishi K, Nakata Y, Oda Y, Iyo M. Interacting Roles of COMT and GAD1 Genes in Patients with Treatment-Resistant Schizophrenia: a Genetic Association Study of Schizophrenia Patients and Healthy Controls. J Mol Neurosci 2021; 71:2575-2582. [PMID: 34125398 DOI: 10.1007/s12031-021-01866-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/03/2021] [Indexed: 12/21/2022]
Abstract
The projection from dopaminergic neurons to gamma-aminobutyric acid (GABA) interneurons in the prefrontal cortex is involved in the etiology of schizophrenia. The impact of interacting effects between dopamine signals and the expression of GABA on the clinical phenotypes of schizophrenia has not been studied. Since these interactions could be closely involved in prefrontal cortex functions, patients with specific alleles of these relevant molecules (which lead to lower or vulnerable genetic functions) may develop treatment-refractory symptoms. We conducted a genetic association study focusing on COMT and GAD1 genes for a treatment-resistant schizophrenia (TRS) group (n=171), a non-TRS group (n=592), and healthy controls (HC: n=447), and we examined allelic combinations specific to TRS. The results revealed that the percentage of subjects with Met allele of rs4680 on the COMT gene and C/C homozygote of rs3470934 on the GAD1 gene was significantly higher in the TRS group than the other two groups. There was no significant difference between the non-TRS group and HC groups. Considering the direction of functions of these single-nucleotide polymorphisms revealed by previous studies, we speculate that subjects with the Met/CC allelic combination could have a higher dopamine level and a lower expression of GABA in the prefrontal cortex. Our results suggest that an interaction between the dopaminergic signal and GABA signal intensities could differ between TRS patients and patients with other types of schizophrenia and healthy subjects.
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Affiliation(s)
- Masanobu Kogure
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Nobuhisa Kanahara
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan.
- Division of Medical Treatment and Rehabilitation, Center for Forensic Mental Health, Chiba University, Chiba, Japan.
| | - Atsuhiro Miyazawa
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
- Doujin-kai Kisarazu Hospital, Chiba, Japan
| | - Kengo Oishi
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
- Department of Cyclic Innovation, Japan Agency for Medical Research Development, Tokyo, Japan
| | - Yusuke Nakata
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Yasunori Oda
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Masaomi Iyo
- Department of Psychiatry, Chiba University Graduate School of Medicine, Chiba, Japan
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8
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Song Y, Seo S, Lamichhane S, Seo J, Hong JT, Cha HJ, Yun J. Limonene has anti-anxiety activity via adenosine A2A receptor-mediated regulation of dopaminergic and GABAergic neuronal function in the striatum. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2021; 83:153474. [PMID: 33548867 DOI: 10.1016/j.phymed.2021.153474] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 11/11/2020] [Accepted: 01/17/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Limonene, a common terpene found in citrus fruits, is assumed to reduce stress and mood disorders. Dopamine and γ-aminobutyric acid (GABA) have been reported to play an important role in modulating anxiety in different parts of the brain. HYPOTHESIS/PURPOSE Herein, we report the anxiolytic activity of limonene. In addition, we identified a possible mechanism underlying the effect of limonene on DAergic and GABAergic neurotransmission. STUDY DESIGN In this study, mice were injected with saline in the control group and limonene in the test group before behavioral analysis. We performed immunoblotting and high-performance liquid chromatography (HPLC) analysis after the behavioral study. RESULTS The limonene treated group showed increased locomotor activity and open-arm preference in the elevated plus maze experiment. Limonene treatment increased the expression of both tyrosine hydroxylase and GAD-67 proteins and significantly upregulated dopamine levels in the striatum. Furthermore, tissue dopamine levels were increased in the striatum of mice following limonene treatment, and depolarization-induced GABA release was enhanced by limonene pre-treatment in PC-12 cells. Interestingly, limonene-induced anxiolytic activity and GABA release augmentation were blocked by an adenosine A2A receptor (A2AR) antagonist. CONCLUSION Our results suggest that limonene inhibits anxiety-related behavior through A2A receptor-mediated regulation of DAergic and GABAergic neuronal activity.
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Affiliation(s)
- Yunjeong Song
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 28160, Republic of Korea
| | - Sowoon Seo
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 28160, Republic of Korea
| | - Santosh Lamichhane
- Department of Pharmacy, Wonkwang University, Iksandaero 460, Iksan, Jeonbuk 54538, Republic of Korea
| | - Jungwon Seo
- Department of Pharmacy, Wonkwang University, Iksandaero 460, Iksan, Jeonbuk 54538, Republic of Korea
| | - Jin Tae Hong
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 28160, Republic of Korea
| | - Hye Jin Cha
- Narcotics Policy Division, Ministry of Food and Drug Safety, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 28160, Republic of Korea.
| | - Jaesuk Yun
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 28160, Republic of Korea.
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9
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Morgan NV, Yngvadottir B, O'Driscoll M, Clark GR, Walsh D, Martin E, Tee L, Reid E, Titheradge HL, Maher ER. Evidence that autosomal recessive spastic cerebral palsy-1 (CPSQ1) is caused by a missense variant in HPDL. Brain Commun 2021; 3:fcab002. [PMID: 33634263 PMCID: PMC7892364 DOI: 10.1093/braincomms/fcab002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/15/2020] [Accepted: 11/26/2020] [Indexed: 01/05/2023] Open
Abstract
A subset of individuals diagnosed with cerebral palsy will have an underlying genetic diagnosis. Previously, a missense variant in GAD1 was described as a candidate mutation in a single family diagnosed with autosomal recessive spastic cerebral palsy-1 (CPSQ1; OMIM 603513). Following the ascertainment of a further branch of the CPSQ1 kindred, we found that the previously reported GAD1 variant did not segregate with the neurological disease phenotype in the recently ascertained branch of the kindred. Following genetic linkage studies to map autozygous regions and whole-exome sequencing, a missense variant (c.527 T > C; p. Leu176Pro, rs773333490) in the HPDL gene was detected and found to segregate with disease status in both branches of the kindred. HPDL encodes a 371-amino acid protein (4-Hydroxyphenylpyruvate Dioxygenase Like) that localizes to mitochondria but whose function is uncertain. Recently, biallelic loss of function variants and missense substitution-causing variants in HPDL were reported to cause a childhood onset progressive spastic movement disorder with a variable presentation. These findings suggest that HPDL-related neurological disease may mimic spastic cerebral palsy and that GAD1 should not be included in diagnostic gene panels for inherited cerebral palsy.
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Affiliation(s)
- Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Bryndis Yngvadottir
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - Mary O'Driscoll
- West Midlands Regional Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's NHS Trust, Birmingham B15 2TG, UK
| | - Graeme R Clark
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - Diana Walsh
- West Midlands Regional Genetics Laboratory, Birmingham Women's and Children's NHS Trust, Birmingham B15 2TG, UK
| | - Ezequiel Martin
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK.,Oncology Department, Cancer Molecular Diagnostics Laboratory, University of Cambridge, Cambridge CB2 0XZ, UK
| | - Louise Tee
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Evan Reid
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK.,Cambridge Institute of Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Hannah L Titheradge
- West Midlands Regional Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's NHS Trust, Birmingham B15 2TG, UK
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
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10
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Neuray C, Maroofian R, Scala M, Sultan T, Pai GS, Mojarrad M, Khashab HE, deHoll L, Yue W, Alsaif HS, Zanetti MN, Bello O, Person R, Eslahi A, Khazaei Z, Feizabadi MH, Efthymiou S, El-Bassyouni HT, Soliman DR, Tekes S, Ozer L, Baltaci V, Khan S, Beetz C, Amr KS, Salpietro V, Jamshidi Y, Alkuraya FS, Houlden H. Early-infantile onset epilepsy and developmental delay caused by bi-allelic GAD1 variants. Brain 2020; 143:2388-2397. [PMID: 32705143 PMCID: PMC7447512 DOI: 10.1093/brain/awaa178] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/31/2020] [Accepted: 04/06/2020] [Indexed: 01/31/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) and glutamate are the most abundant amino acid neurotransmitters in the brain. GABA, an inhibitory neurotransmitter, is synthesized by glutamic acid decarboxylase (GAD). Its predominant isoform GAD67, contributes up to ∼90% of base-level GABA in the CNS, and is encoded by the GAD1 gene. Disruption of GAD1 results in an imbalance of inhibitory and excitatory neurotransmitters, and as Gad1-/- mice die neonatally of severe cleft palate, it has not been possible to determine any potential neurological dysfunction. Furthermore, little is known about the consequence of GAD1 disruption in humans. Here we present six affected individuals from six unrelated families, carrying bi-allelic GAD1 variants, presenting with developmental and epileptic encephalopathy, characterized by early-infantile onset epilepsy and hypotonia with additional variable non-CNS manifestations such as skeletal abnormalities, dysmorphic features and cleft palate. Our findings highlight an important role for GAD1 in seizure induction, neuronal and extraneuronal development, and introduce GAD1 as a new gene associated with developmental and epileptic encephalopathy.
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Affiliation(s)
- Caroline Neuray
- UCL Queen Square Institute of Neurology, University College London, London, UK.,Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria
| | - Reza Maroofian
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marcello Scala
- UCL Queen Square Institute of Neurology, University College London, London, UK.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Tipu Sultan
- Department of Pediatric Neurology, Children's Hospital and Institute of Child Health, Lahore, Pakistan
| | | | - Majid Mojarrad
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Genetic Center of Khorasan Razavi, Mashhad, Iran
| | - Heba El Khashab
- Department of Pediatrics, Children's Hospital, Ain Shams University, Cairo, Egypt.,Department of Pediatrics, Dr. Suliman Al Habib Medical Group, Riyadh, Saudi Arabia
| | | | - Wyatt Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK
| | - Hessa S Alsaif
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maria N Zanetti
- Department of Clinical and Experimental Epilepsy, University College London, London, UK
| | - Oscar Bello
- Department of Clinical and Experimental Epilepsy, University College London, London, UK
| | | | - Atieh Eslahi
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Masoumeh H Feizabadi
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Stephanie Efthymiou
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | | | | | - Doaa R Soliman
- Department of Pediatrics, Faculty of Medicine, Benha University, Benha, Egypt
| | - Selahattin Tekes
- Dicle University, School of Medicine, Department of Medical Genetics, Diyarbakir, Turkey
| | - Leyla Ozer
- Yuksek Ihtisas University, School of Medicine, Department of Medical Genetics, Ankara, Turkey
| | | | | | | | - Khalda S Amr
- Molecular Genetics Department, National Research Centre, Cairo, Egypt
| | - Vincenzo Salpietro
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Yalda Jamshidi
- Molecular and Clinical Sciences Institute St George's, University of London, UK
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center Riyadh, Saudi Arabia
| | - Henry Houlden
- UCL Queen Square Institute of Neurology, University College London, London, UK
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11
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Chatron N, Becker F, Morsy H, Schmidts M, Hardies K, Tuysuz B, Roselli S, Najafi M, Alkaya DU, Ashrafzadeh F, Nabil A, Omar T, Maroofian R, Karimiani EG, Hussien H, Kok F, Ramos L, Gunes N, Bilguvar K, Labalme A, Alix E, Sanlaville D, de Bellescize J, Poulat AL, Moslemi AR, Lerche H, May P, Lesca G, Weckhuysen S, Tajsharghi H. Bi-allelic GAD1 variants cause a neonatal onset syndromic developmental and epileptic encephalopathy. Brain 2020; 143:1447-1461. [PMID: 32282878 PMCID: PMC7241960 DOI: 10.1093/brain/awaa085] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 01/13/2020] [Accepted: 03/05/2020] [Indexed: 12/22/2022] Open
Abstract
Developmental and epileptic encephalopathies are a heterogeneous group of early-onset epilepsy syndromes dramatically impairing neurodevelopment. Modern genomic technologies have revealed a number of monogenic origins and opened the door to therapeutic hopes. Here we describe a new syndromic developmental and epileptic encephalopathy caused by bi-allelic loss-of-function variants in GAD1, as presented by 11 patients from six independent consanguineous families. Seizure onset occurred in the first 2 months of life in all patients. All 10 patients, from whom early disease history was available, presented with seizure onset in the first month of life, mainly consisting of epileptic spasms or myoclonic seizures. Early EEG showed suppression-burst or pattern of burst attenuation or hypsarrhythmia if only recorded in the post-neonatal period. Eight patients had joint contractures and/or pes equinovarus. Seven patients presented a cleft palate and two also had an omphalocele, reproducing the phenotype of the knockout Gad1-/- mouse model. Four patients died before 4 years of age. GAD1 encodes the glutamate decarboxylase enzyme GAD67, a critical actor of the γ-aminobutyric acid (GABA) metabolism as it catalyses the decarboxylation of glutamic acid to form GABA. Our findings evoke a novel syndrome related to GAD67 deficiency, characterized by the unique association of developmental and epileptic encephalopathies, cleft palate, joint contractures and/or omphalocele.
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Affiliation(s)
- Nicolas Chatron
- Genetics Department, Lyon University Hospital, Lyon, France.,Institut NeuroMyoGène CNRS UMR 5310 - INSERM U1217 Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Felicitas Becker
- Department of Neurology, University of Ulm, Ulm, Germany.,University of Tübingen, Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
| | - Heba Morsy
- Human Genetics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Miriam Schmidts
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 10, 6525KL Nijmegen, The Netherlands.,Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany
| | - Katia Hardies
- Neurogenetics Group, VIB-Center for Molecular Neurology, University of Antwerp, Antwerp, Belgium
| | - Beyhan Tuysuz
- Department of Pediatric Genetics, Istanbul University-Cerrahpasa, Medical Faculty, Istanbul, Turkey
| | - Sandra Roselli
- Department of Pathology, University of Gothenburg, Sahlgrenska University Hospital, Sweden
| | - Maryam Najafi
- Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 10, 6525KL Nijmegen, The Netherlands
| | - Dilek Uludag Alkaya
- Department of Pediatric Genetics, Istanbul University-Cerrahpasa, Medical Faculty, Istanbul, Turkey
| | - Farah Ashrafzadeh
- Department of Paediatric Neurology, Ghaem Medical Centre, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amira Nabil
- Human Genetics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Tarek Omar
- Pediatrics Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Reza Maroofian
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Ehsan Ghayoor Karimiani
- Genetics Research Centre, Molecular and Clinical Sciences Institute, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK.,Innovative medical research center, Mashhad branch, Islamic Azad University, Mashhad, Iran
| | - Haytham Hussien
- Pediatrics Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Fernando Kok
- Universidade de Sao Paulo Faculdade de Medicina, Sao Paulo, SP, Brazil
| | - Luiza Ramos
- Universidade de Sao Paulo Faculdade de Medicina, Sao Paulo, SP, Brazil
| | - Nilay Gunes
- Department of Pediatric Genetics, Istanbul University-Cerrahpasa, Medical Faculty, Istanbul, Turkey
| | - Kaya Bilguvar
- Department of Genetics, Yale Center for Genome Analysis (YCGA), Yale University, School of Medicine, New Haven, Connecticut
| | - Audrey Labalme
- Genetics Department, Lyon University Hospital, Lyon, France
| | - Eudeline Alix
- Genetics Department, Lyon University Hospital, Lyon, France
| | - Damien Sanlaville
- Institut NeuroMyoGène CNRS UMR 5310 - INSERM U1217 Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Julitta de Bellescize
- Department of Pediatric Clinical Epileptology, Sleep Disorders and Functional Neurology, ERN EpiCARE, University Hospitals of Lyon, Lyon, France
| | - Anne-Lise Poulat
- Department of Pediatric Neurology, Lyon University Hospital, Lyon, France
| | | | - Ali-Reza Moslemi
- Department of Pathology, University of Gothenburg, Sahlgrenska University Hospital, Sweden
| | - Holger Lerche
- University of Tübingen, Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
| | - Patrick May
- Luxemburg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
| | - Gaetan Lesca
- Genetics Department, Lyon University Hospital, Lyon, France.,Institut NeuroMyoGène CNRS UMR 5310 - INSERM U1217 Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Sarah Weckhuysen
- Neurogenetics Group, VIB-Center for Molecular Neurology, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Homa Tajsharghi
- School of Health Sciences, Division Biomedicine, University of Skovde, Skovde, Sweden
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12
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Saxena R, Babadi M, Namvarhaghighi H, Roullet FI. Role of environmental factors and epigenetics in autism spectrum disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 173:35-60. [PMID: 32711816 DOI: 10.1016/bs.pmbts.2020.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder thought to be caused by predisposing high-risk genes that may be altered during the early development by environmental factors. The impact of maternal challenges during pregnancy on the prevalence of ASD has been widely studied in clinical and animal studies. Here, we review some clinical and pre-clinical evidence that links environmental factors (i.e., infection, air pollution, pesticides, valproic acid and folic acid) and the risk of ASD. Additionally, certain prenatal environmental challenges such as the valproate and folate prenatal exposures allow us to study mechanisms possibly linked to the etiology of ASD, for instance the epigenetic processes. These mechanistic pathways are also presented and discussed in this chapter.
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Affiliation(s)
- Roheeni Saxena
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Melika Babadi
- School of Interdisciplinary Science, McMaster University, Hamilton, ON, Canada
| | | | - Florence I Roullet
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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13
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Friedl RM, Raja S, Metzler MA, Patel ND, Brittian KR, Jones SP, Sandell LL. RDH10 function is necessary for spontaneous fetal mouth movement that facilitates palate shelf elevation. Dis Model Mech 2019; 12:12/7/dmm039073. [PMID: 31300413 PMCID: PMC6679383 DOI: 10.1242/dmm.039073] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022] Open
Abstract
Cleft palate is a common birth defect, occurring in approximately 1 in 1000 live births worldwide. Known etiological mechanisms of cleft palate include defects within developing palate shelf tissues, defects in mandibular growth and defects in spontaneous fetal mouth movement. Until now, experimental studies directly documenting fetal mouth immobility as an underlying cause of cleft palate have been limited to models lacking neurotransmission. This study extends the range of anomalies directly demonstrated to have fetal mouth movement defects correlated with cleft palate. Here, we show that mouse embryos deficient in retinoic acid (RA) have mispatterned pharyngeal nerves and skeletal elements that block spontaneous fetal mouth movement in utero. Using X-ray microtomography, in utero ultrasound video, ex vivo culture and tissue staining, we demonstrate that proper retinoid signaling and pharyngeal patterning are crucial for the fetal mouth movement needed for palate formation. Embryos with deficient retinoid signaling were generated by stage-specific inactivation of retinol dehydrogenase 10 (Rdh10), a gene crucial for the production of RA during embryogenesis. The finding that cleft palate in retinoid deficiency results from a lack of fetal mouth movement might help elucidate cleft palate etiology and improve early diagnosis in human disorders involving defects of pharyngeal development. Summary: Fetal mouth immobility and defects in pharyngeal patterning underlie cleft palate in retinoid-deficient Rdh10 mutant mouse embryos.
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Affiliation(s)
- Regina M Friedl
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202, USA
| | - Swetha Raja
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202, USA
| | - Melissa A Metzler
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202, USA
| | - Niti D Patel
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202, USA
| | - Kenneth R Brittian
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202, USA
| | - Steven P Jones
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202, USA
| | - Lisa L Sandell
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY 40202, USA
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14
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Walia V, Garg C, Garg M. Lithium potentiated, pyridoxine abolished and fluoxetine attenuated the anxiolytic effect of diazepam in mice. Brain Res Bull 2019; 150:343-353. [PMID: 31201833 DOI: 10.1016/j.brainresbull.2019.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 05/05/2019] [Accepted: 06/10/2019] [Indexed: 11/19/2022]
Abstract
In the present study, the anxiolytic effect of diazepam (1 and 2 mg/kg, i.p.) was determined alone and in combination with lithium (50 mg/kg, i.p.), pyridoxine (90 mg/kg, i.p.) and fluoxetine (10 mg/kg, i.p.) using elevated plus maze (EPM) and light/dark box (LDB) tests in experimental mice. The effect of various treatments on the brain GABA levels and glutamic acid decarboxylase (GAD) expression were also determined. The results obtained suggested that the diazepam (2 mg/kg, i.p.) exerted anxiolytic effect and significantly increased the brain GABA levels and GAD expression as compared to control group. Fluoxetine (10 mg/kg, i.p.) exerted anxiogenic effects, but did not affect the brain GABA levels and GAD activity significantly as compared to control. Pretreatments of pyridoxine (90 mg/kg, i.p.) abolished; lithium (50 mg/kg, i.p.) potentiated while fluoxetine (10 mg/kg, i.p.) attenuated the anxiolytic and neurochemical effects of diazepam (1 and 2 mg/kg, i.p.) treatment in mice. Therefore, the combined treatment of lithium and diazepam might be a promising treatment for anxiety.
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Affiliation(s)
- Vaibhav Walia
- Department of Pharmaceutical Sciences, M.D University Rohtak, Haryana, India
| | - Chanchal Garg
- Department of Pharmaceutical Sciences, M.D University Rohtak, Haryana, India
| | - Munish Garg
- Department of Pharmaceutical Sciences, M.D University Rohtak, Haryana, India.
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15
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Marrero-Rosado B, Rossetti F, Rice MW, Moffett MC, Lee RB, Stone MF, Lumley LA. Age-Related Susceptibility to Epileptogenesis and Neuronal Loss in Male Fischer Rats Exposed to Soman and Treated With Medical Countermeasures. Toxicol Sci 2019; 164:142-152. [PMID: 29596688 DOI: 10.1093/toxsci/kfy065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Elderly individuals compose a large percentage of the world population; however, few studies have addressed the efficacy of current medical countermeasures (MCMs) against the effects of chemical warfare nerve agent exposure in aged populations. We evaluated the efficacy of the anticonvulsant diazepam in an old adult rat model of soman (GD) poisoning and compared the toxic effects to those observed in young adult rats when anticonvulsant treatment is delayed. After determining their respective median lethal dose (LD50) of GD, we exposed young adult and old adult rats to an equitoxic 1.2 LD50 dose of GD followed by treatment with atropine sulfate and the oxime HI-6 at 1 min after exposure, and diazepam at 30 min after seizure onset. Old adult rats that presented with status epilepticus were more susceptible to developing spontaneous recurrent seizures (SRSs). Neuropathological analysis revealed that in rats of both age groups that developed SRS, there was a significant reduction in the density of mature neurons in the piriform cortex, thalamus, and amygdala, with more pronounced neuronal loss in the thalamus of old adult rats compared with young adult rats. Furthermore, old adult rats displayed a reduced density of cells expressing glutamic acid decarboxylase 67, a marker of GABAergic interneurons, in the basolateral amygdala and piriform cortex, and a reduction of astrocyte activation in the piriform cortex. Our observations demonstrate the reduced effectiveness of current MCM in an old adult animal model of GD exposure and strongly suggest the need for countermeasures that are more tailored to the vulnerabilities of an aging population.
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Affiliation(s)
- Brenda Marrero-Rosado
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
| | - Franco Rossetti
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910
| | - Matthew W Rice
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
| | - Mark C Moffett
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
| | - Robyn B Lee
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
| | - Michael F Stone
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
| | - Lucille A Lumley
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010
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16
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O’Connor MJ, Beebe LL, Deodato D, Ball RE, Page AT, VanLeuven AJ, Harris KT, Park S, Hariharan V, Lauderdale JD, Dore TM. Bypassing Glutamic Acid Decarboxylase 1 (Gad1) Induced Craniofacial Defects with a Photoactivatable Translation Blocker Morpholino. ACS Chem Neurosci 2019; 10:266-278. [PMID: 30200754 PMCID: PMC6337688 DOI: 10.1021/acschemneuro.8b00231] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
![]()
γ-Amino
butyric acid (GABA) mediated signaling is critical
in the central and enteric nervous systems, pancreas, lungs, and other
tissues. It is associated with many neurological disorders and craniofacial
development. Glutamic acid decarboxylase (GAD) synthesizes GABA from
glutamate, and knockdown of the gad1 gene results
in craniofacial defects that are lethal in zebrafish. To bypass this
and enable observation of the neurological defects resulting from
knocking down gad1 expression, a photoactivatable
morpholino oligonucleotide (MO) against gad1 was
prepared by cyclization with a photocleavable linker rendering the
MO inactive. The cyclized MO was stable in the dark and toward degradative
enzymes and was completely linearized upon brief exposure to 405 nm
light. In the course of investigating the function of the ccMOs in
zebrafish, we discovered that zebrafish possess paralogous gad1 genes, gad1a and gad1b. A gad1b MO injected at the 1–4 cell stage
caused severe morphological defects in head development, which could
be bypassed, enabling the fish to develop normally, if the fish were
injected with a photoactivatable, cyclized gad1b MO
and grown in the dark. At 1 day post fertilization (dpf), light activation
of the gad1b MO followed by observation at 3 and
7 dpf led to increased and abnormal electrophysiological brain activity
compared to wild type animals. The photocleavable linker can be used
to cyclize and inactivate any MO, and represents a general strategy
to parse the function of developmentally important genes in a spatiotemporal
manner.
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Affiliation(s)
- Matthew J. O’Connor
- New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates
| | - Lindsey L. Beebe
- Department of Genetics, University of Georgia, Athens, Georgia 30602, United States
| | - Davide Deodato
- New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates
| | - Rebecca E. Ball
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - A. Tyler Page
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Ariel J. VanLeuven
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Kyle T. Harris
- Department of Chemistry, University of Georgia, Athens, Georgia 30602 United States
| | - Sungdae Park
- Department of Genetics, University of Georgia, Athens, Georgia 30602, United States
| | - Vani Hariharan
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - James D. Lauderdale
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, United States
- Neuroscience
Division
of the Biomedical and Health Sciences Institute, Athens, Georgia 30602, United States
| | - Timothy M. Dore
- New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates
- Department of Chemistry, University of Georgia, Athens, Georgia 30602 United States
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17
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Katahira T, Miyazaki N, Motoyama J. Immediate effects of maternal separation on the development of interneurons derived from medial ganglionic eminence in the neonatal mouse hippocampus. Dev Growth Differ 2018; 60:278-290. [DOI: 10.1111/dgd.12540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Tatsuya Katahira
- Organization of Advanced Research and Education; Doshisha University; Kyoto Japan
| | | | - Jun Motoyama
- Laboratory of Developmental Neurobiology; Graduate School of Brain Science; Doshisha University; Kyoto Japan
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18
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Tao R, Davis KN, Li C, Shin JH, Gao Y, Jaffe AE, Gondré-Lewis MC, Weinberger DR, Kleinman JE, Hyde TM. GAD1 alternative transcripts and DNA methylation in human prefrontal cortex and hippocampus in brain development, schizophrenia. Mol Psychiatry 2018; 23:1496-1505. [PMID: 28485403 PMCID: PMC7564279 DOI: 10.1038/mp.2017.105] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/20/2017] [Accepted: 04/04/2017] [Indexed: 12/25/2022]
Abstract
Genetic variations and adverse environmental events in utero or shortly after birth can lead to abnormal brain development and increased risk of schizophrenia. γ-Aminobutyric acid (GABA), the major inhibitory neurotransmitter in the mammalian brain, plays a vital role in normal brain development. GABA synthesis is controlled by enzymes derived from two glutamic acid decarboxylase (GAD) genes, GAD1 and GAD2, both of which produce transcript isoforms. While the full-length GAD1 transcript (GAD67) has been implicated in the neuropathology of schizophrenia, the transcript structure of GAD1 in the human brain has not been fully characterized. In this study, with the use of RNA sequencing and PCR technologies, we report the discovery of 10 novel transcripts of GAD1 in the human brain. Expression levels of four novel GAD1 transcripts (8A, 8B, I80 and I86) showed a lifespan trajectory expression pattern that is anticorrelated with the expression of the full-length GAD1 transcript. In addition, methylation levels of two CpG loci within the putative GAD1 promoter were significantly associated with the schizophrenia-risk SNP rs3749034 and with the expression of GAD25 in dorsolateral prefrontal cortex (DLPFC). Moreover, schizophrenia patients who had completed suicide and/or were positive for nicotine exposure had significantly higher full-length GAD1 expression in the DLPFC. Alternative splicing of GAD1 and epigenetic state appear to play roles in the developmental profile of GAD1 expression and may contribute to GABA dysfunction in the PFC and hippocampus of patients with schizophrenia.
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Affiliation(s)
- Ran Tao
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Kasey N. Davis
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Laboratory for Neurodevelopment, Department of Anatomy, Howard University College of Medicine, Washington D.C., USA
| | - Chao Li
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Joo Heon Shin
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Yuan Gao
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Andrew E. Jaffe
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Marjorie C. Gondré-Lewis
- Laboratory for Neurodevelopment, Department of Anatomy, Howard University College of Medicine, Washington D.C., USA
| | - Daniel R. Weinberger
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Psychiatry and Behavior Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Joel E. Kleinman
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Psychiatry and Behavior Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Thomas M. Hyde
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Psychiatry and Behavior Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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19
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Albers HE, Walton JC, Gamble KL, McNeill JK, Hummer DL. The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus. Front Neuroendocrinol 2017; 44:35-82. [PMID: 27894927 PMCID: PMC5225159 DOI: 10.1016/j.yfrne.2016.11.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 11/22/2016] [Indexed: 12/31/2022]
Abstract
Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAA receptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABAB receptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker.
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Affiliation(s)
- H Elliott Albers
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
| | - James C Walton
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - John K McNeill
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Daniel L Hummer
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Department of Psychology, Morehouse College, Atlanta, GA 30314, United States
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20
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Distinct development of the glycinergic terminals in the ventral and dorsal horns of the mouse cervical spinal cord. Neuroscience 2016; 343:459-471. [PMID: 28039040 DOI: 10.1016/j.neuroscience.2016.12.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 02/01/2023]
Abstract
In the spinal cord, glycine and γ-amino butyric acid (GABA) are inhibitory neurotransmitters. However, the ontogeny of the glycinergic network remains unclear. To address this point, we examined the developmental formation of glycinergic terminals by immunohistochemistry for glycine transporter 2 (GlyT2), a marker of glycinergic terminals, in developing mouse cervical spinal cord. Furthermore, the developmental localization of GlyT2 was compared with that of glutamic acid decarboxylase (GAD), a marker of GABAergic terminals, and vesicular GABA transporter (VGAT), a marker of inhibitory terminals, by single and double immunolabeling. GlyT2-positive dots (glycinergic terminals) were first detected in the marginal zone on embryonic day 14 (E14). In the ventral horn, they were detected at E16 and increased in observed density during postnatal development. Until postnatal day 7 (P7), GAD-positive dots (GABAergic terminals) were dominant and GlyT2 immunolabeling was localized at GAD-positive dots. During the second postnatal week, GABAergic terminals markedly decreased and glycinergic terminals became dominant. In the dorsal horn, glycinergic terminals were detected at P0 in lamina IV and P7 in lamina III and developmentally increased. GlyT2 was also localized at GAD-positive dots, and colocalizing dots were dominant at P21. VGAT-positive dots (inhibitory terminals) continued to increase until P21. These results suggest that GABAergic terminals first appear during embryonic development and may often change to colocalizing terminals throughout the gray matter during development. The colocalizing terminals may remain in the dorsal horn, whereas in the ventral horn, colocalizing terminals may give rise to glycinergic terminals.
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21
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Growth hormone biases amygdala network activation after fear learning. Transl Psychiatry 2016; 6:e960. [PMID: 27898076 PMCID: PMC5290350 DOI: 10.1038/tp.2016.203] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 07/07/2016] [Accepted: 07/18/2016] [Indexed: 01/27/2023] Open
Abstract
Prolonged stress exposure is a risk factor for developing posttraumatic stress disorder, a disorder characterized by the 'over-encoding' of a traumatic experience. A potential mechanism by which this occurs is through upregulation of growth hormone (GH) in the amygdala. Here we test the hypotheses that GH promotes the over-encoding of fearful memories by increasing the number of neurons activated during memory encoding and biasing the allocation of neuronal activation, one aspect of the process by which neurons compete to encode memories, to favor neurons that have stronger inputs. Viral overexpression of GH in the amygdala increased the number of amygdala cells activated by fear memory formation. GH-overexpressing cells were especially biased to express the immediate early gene c-Fos after fear conditioning, revealing strong autocrine actions of GH in the amygdala. In addition, we observed dramatically enhanced dendritic spine density in GH-overexpressing neurons. These data elucidate a previously unrecognized autocrine role for GH in the regulation of amygdala neuron function and identify specific mechanisms by which chronic stress, by enhancing GH in the amygdala, may predispose an individual to excessive fear memory formation.
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Urrutia M, Fernández S, González M, Vilches R, Rojas P, Vásquez M, Kurte M, Vega-Letter AM, Carrión F, Figueroa F, Rojas P, Irarrázabal C, Fuentealba RA. Overexpression of Glutamate Decarboxylase in Mesenchymal Stem Cells Enhances Their Immunosuppressive Properties and Increases GABA and Nitric Oxide Levels. PLoS One 2016; 11:e0163735. [PMID: 27662193 PMCID: PMC5035029 DOI: 10.1371/journal.pone.0163735] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/13/2016] [Indexed: 12/12/2022] Open
Abstract
The neurotransmitter GABA has been recently identified as a potent immunosuppressive agent that targets both innate and adaptive immune systems and prevents disease progression of several autoimmunity models. Mesenchymal stem cells (MSCs) are self-renewing progenitor cells that differentiate into various cell types under specific conditions, including neurons. In addition, MSC possess strong immunosuppressive capabilities. Upon cytokine priming, undifferentiated MSC suppress T-cell proliferation via cell-to-cell contact mechanisms and the secretion of soluble factors like nitric oxide, prostaglandin E2 and IDO. Although MSC and MSC-derived neuron-like cells express some GABAergic markers in vitro, the role for GABAergic signaling in MSC-mediated immunosuppression remains completely unexplored. Here, we demonstrate that pro-inflammatory cytokines selectively regulate GAD-67 expression in murine bone marrow-MSC. However, expression of GAD-65 is required for maximal GABA release by MSC. Gain of function experiments using GAD-67 and GAD-65 co-expression demonstrates that GAD increases immunosuppressive function in the absence of pro-inflammatory licensing. Moreover, GAD expression in MSC evokes an increase in both GABA and NO levels in the supernatants of co-cultured MSC with activated splenocytes. Notably, the increase in NO levels by GAD expression was not observed in cultures of isolated MSC expressing GAD, suggesting crosstalk between these two pathways in the setting of immunosuppression. These results indicate that GAD expression increases MSC-mediated immunosuppression via secretion of immunosuppressive agents. Our findings may help reconsider GABAergic activation in MSC for immunological disorders.
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Affiliation(s)
- Mariana Urrutia
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Sebastián Fernández
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Marisol González
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Rodrigo Vilches
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Pablo Rojas
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Manuel Vásquez
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Mónica Kurte
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Ana María Vega-Letter
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Flavio Carrión
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Fernando Figueroa
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Patricio Rojas
- Departamento de Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Carlos Irarrázabal
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Rodrigo A. Fuentealba
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
- * E-mail:
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Transcriptional regulation of GAD1 GABA synthesis gene in the prefrontal cortex of subjects with schizophrenia. Schizophr Res 2015; 167:28-34. [PMID: 25458568 PMCID: PMC4417100 DOI: 10.1016/j.schres.2014.10.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 10/08/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022]
Abstract
Expression of GAD1 GABA synthesis enzyme is highly regulated by neuronal activity and reaches mature levels in the prefrontal cortex not before adolescence. A significant portion of cases diagnosed with schizophrenia show deficits in GAD1 RNA and protein levels in multiple areas of adult cerebral cortex, possibly reflecting molecular or cellular defects in subtypes of GABAergic interneurons essential for network synchronization and cognition. Here, we review 20years of progress towards a better understanding of disease-related regulation of GAD1 gene expression. For example, deficits in cortical GAD1 RNA in some cases of schizophrenia are associated with changes in the epigenetic architecture of the promoter, affecting DNA methylation patterns and nucleosomal histone modifications. These localized chromatin defects at the 5' end of GAD1 are superimposed by disordered locus-specific chromosomal conformations, including weakening of long-range promoter-enhancer loopings and physical disconnection of GAD1 core promoter sequences from cis-regulatory elements positioned 50 kilobases further upstream. Studies on the 3-dimensional architecture of the GAD1 locus in neurons, including developmentally regulated higher order chromatin compromised by the disease process, together with exploration of locus-specific epigenetic interventions in animal models, could pave the way for future treatments of psychosis and schizophrenia.
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GAD65/GAD67 double knockout mice exhibit intermediate severity in both cleft palate and omphalocele compared with GAD67 knockout and VGAT knockout mice. Neuroscience 2015; 288:86-93. [DOI: 10.1016/j.neuroscience.2014.12.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 12/11/2014] [Accepted: 12/13/2014] [Indexed: 12/24/2022]
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Agca S, Houen G, Trier NH. Characterization of continuous B-cell epitopes in the N-terminus of glutamate decarboxylase67 using monoclonal antibodies. J Pept Sci 2014; 20:928-34. [DOI: 10.1002/psc.2703] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 08/27/2014] [Accepted: 09/01/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Selin Agca
- Department of Clinical Biochemistry, Immunology and Genetics; Statens Serum Institut; Artillerivej 5 2300 Copenhagen S Denmark
- Department of Molecular Biology and Genetics; Aarhus University; Forskerparken - Gustav Wieds Vej 10 8000 Aarhus C Denmark
| | - Gunnar Houen
- Department of Clinical Biochemistry, Immunology and Genetics; Statens Serum Institut; Artillerivej 5 2300 Copenhagen S Denmark
| | - Nicole Hartwig Trier
- Department of Clinical Biochemistry, Immunology and Genetics; Statens Serum Institut; Artillerivej 5 2300 Copenhagen S Denmark
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Johnson PL, Federici LM, Shekhar A. Etiology, triggers and neurochemical circuits associated with unexpected, expected, and laboratory-induced panic attacks. Neurosci Biobehav Rev 2014; 46 Pt 3:429-54. [PMID: 25130976 DOI: 10.1016/j.neubiorev.2014.07.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 06/24/2014] [Accepted: 07/31/2014] [Indexed: 12/18/2022]
Abstract
Panic disorder (PD) is a severe anxiety disorder that is characterized by recurrent panic attacks (PA), which can be unexpected (uPA, i.e., no clear identifiable trigger) or expected (ePA). Panic typically involves an abrupt feeling of catastrophic fear or distress accompanied by physiological symptoms such as palpitations, racing heart, thermal sensations, and sweating. Recurrent uPA and ePA can also lead to agoraphobia, where subjects with PD avoid situations that were associated with PA. Here we will review recent developments in our understanding of PD, which includes discussions on: symptoms and signs associated with uPA and ePAs; Diagnosis of PD and the new DSM-V; biological etiology such as heritability and gene×environment and gene×hormonal development interactions; comparisons between laboratory and naturally occurring uPAs and ePAs; neurochemical systems that are associated with clinical PAs (e.g. gene associations; targets for triggering or treating PAs), adaptive fear and panic response concepts in the context of new NIH RDoc approach; and finally strengths and weaknesses of translational animal models of adaptive and pathological panic states.
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Affiliation(s)
- Philip L Johnson
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Lauren M Federici
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anantha Shekhar
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Clinical and Translational Sciences Institute, Indiana University School of Medicine, Indianapolis, IN, USA
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Vastagh C, Schwirtlich M, Kwakowsky A, Erdélyi F, Margolis FL, Yanagawa Y, Katarova Z, Szabó G. The spatiotemporal segregation of GAD forms defines distinct GABA signaling functions in the developing mouse olfactory system and provides novel insights into the origin and migration of GnRH neurons. Dev Neurobiol 2014; 75:249-70. [PMID: 25125027 DOI: 10.1002/dneu.22222] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/18/2014] [Accepted: 08/06/2014] [Indexed: 01/26/2023]
Abstract
Gamma-aminobutyric acid (GABA) has a dual role as an inhibitory neurotransmitter in the adult central nervous system (CNS) and as a signaling molecule exerting largely excitatory actions during development. The rate-limiting step of GABA synthesis is catalyzed by two glutamic acid decarboxylase isoforms GAD65 and GAD67 coexpressed in the GABAergic neurons of the CNS. Here we report that the two GADs show virtually nonoverlapping expression patterns consistent with distinct roles in the developing peripheral olfactory system. GAD65 is expressed exclusively in undifferentiated neuronal progenitors confined to the proliferative zones of the sensory vomeronasal and olfactory epithelia In contrast GAD67 is expressed in a subregion of the nonsensory epithelium/vomeronasal organ epithelium containing the putative Gonadotropin-releasing hormone (GnRH) progenitors and GnRH neurons migrating from this region through the frontonasal mesenchyme into the basal forebrain. Only GAD67+, but not GAD65+ cells accumulate detectable GABA. We further demonstrate that GAD67 and its embryonic splice variant embryonic GAD (EGAD) concomitant with GnRH are dynamically regulated during GnRH neuronal migration in vivo and in two immortalized cell lines representing migratory (GN11) and postmigratory (GT1-7) stage GnRH neurons, respectively. Analysis of GAD65/67 single and double knock-out embryos revealed that the two GADs play complementary (inhibitory) roles in GnRH migration ultimately modulating the speed and/or direction of GnRH migration. Our results also suggest that GAD65 and GAD67/EGAD characterized by distinct subcellular localization and kinetics have disparate functions during olfactory system development mediating proliferative and migratory responses putatively through specific subcellular GABA pools.
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Affiliation(s)
- Csaba Vastagh
- Division of Medical Gene Technology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary; Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Genetic ablation of VIAAT in glycinergic neurons causes a severe respiratory phenotype and perinatal death. Brain Struct Funct 2014; 220:2835-49. [PMID: 25027639 DOI: 10.1007/s00429-014-0829-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/21/2014] [Indexed: 12/14/2022]
Abstract
Both glycinergic and GABAergic neurons require the vesicular inhibitory amino acid transporter (VIAAT) for synaptic vesicle filling. Presynaptic GABA concentrations are determined by the GABA-synthesizing enzymes glutamate decarboxylase (GAD)65 and GAD67, whereas the presynaptic glycine content depends on the plasma membrane glycine transporter 2 (GlyT2). Although severely impaired, glycinergic transmission is not completely absent in GlyT2-knockout mice, suggesting that other routes of glycine uptake or de novo synthesis of glycine exist in presynaptic terminals. To investigate the consequences of a complete loss of glycinergic transmission, we generated a mouse line with a conditional ablation of VIAAT in glycinergic neurons by crossing mice with loxP-flanked VIAAT alleles with a GlyT2-Cre transgenic mouse line. Interestingly, conditional VIAAT knockout (VIAAT cKO) mice were not viable at birth. In addition to the dominant respiratory failure, VIAAT cKO showed an umbilical hernia and a cleft palate. Immunohistochemistry revealed an almost complete depletion of VIAAT in the brainstem. Electrophysiology revealed the absence of both spontaneous glycinergic and GABAergic inhibitory postsynaptic currents from hypoglossal motoneurons. Our results demonstrate that the deletion of VIAAT in GlyT2-Cre expressing neurons also strongly affects GABAergic transmission and suggest a large overlap of the glycinergic and the GABAergic neuron population during early development in the caudal parts of the brain.
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Kimura R, Kasamatsu A, Koyama T, Fukumoto C, Kouzu Y, Higo M, Endo-Sakamoto Y, Ogawara K, Shiiba M, Tanzawa H, Uzawa K. Glutamate acid decarboxylase 1 promotes metastasis of human oral cancer by β-catenin translocation and MMP7 activation. BMC Cancer 2013; 13:555. [PMID: 24261884 PMCID: PMC3866561 DOI: 10.1186/1471-2407-13-555] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/19/2013] [Indexed: 01/06/2023] Open
Abstract
Background Glutamate decarboxylase 1 (GAD1), a rate-limiting enzyme in the production of γ-aminobutyric acid (GABA), is found in the GABAergic neurons of the central nervous system. Little is known about the relevance of GAD1 to oral squamous cell carcinoma (OSCC). We investigated the expression status of GAD1 and its functional mechanisms in OSCCs. Methods We evaluated GAD1 mRNA and protein expressions in OSCC-derived cells using real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and immunoblotting analyses. To assess the critical functions of GAD1, i.e., cellular proliferation, invasiveness, and migration, OSCC-derived cells were treated with the shRNA and specific GAD1 inhibitor, 3-mercaptopropionic acid (3-MPA). GAD1 expression in 80 patients with primary OSCCs was analyzed and compared to the clinicopathological behaviors of OSCC. Results qRT-PCR and immunoblotting analyses detected frequent up-regulation of GAD1 in OSCC-derived cells compared to human normal oral keratinocytes. Suppression of nuclear localization of β-catenin and MMP7 secretion was observed in GAD1 knockdown and 3-MPA-treated cells. We also found low cellular invasiveness and migratory abilities in GAD1 knockdown and 3-MPA-treated cells. In the clinical samples, GAD1 expression in the primary OSCCs was significantly (P < 0.05) higher than in normal counterparts and was correlated significantly (P < 0.05) with regional lymph node metastasis. Conclusions Our data showed that up-regulation of GAD1 was a characteristic event in OSCCs and that GAD1 was correlated with cellular invasiveness and migration by regulating β-catenin translocation and MMP7 activation. GAD1 might play an important role in controlling tumoral invasiveness and metastasis in oral cancer.
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Affiliation(s)
| | - Atsushi Kasamatsu
- Department of Clinical Molecular Biology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
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Central nervous system effects of prenatal selective serotonin reuptake inhibitors: sensing the signal through the noise. Psychopharmacology (Berl) 2013; 227:567-82. [PMID: 23681158 PMCID: PMC3838633 DOI: 10.1007/s00213-013-3115-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE Women are increasingly prescribed selective serotonin reuptake inhibitors (SSRIs) during pregnancy, with potential implications for neurodevelopment. Whether prenatal SSRI exposure has an effect on neurodevelopment and behavior in the offspring is an important area of investigation. OBJECTIVES The aim of this paper was to review the existing preclinical and clinical literature of prenatal SSRI exposure on serotonin-related behaviors and markers in the offspring. The goal is to determine if there is a signal in the literature that could guide clinical care and/or inform research. RESULTS Preclinical studies (n = 4) showed SSRI exposure during development enhanced depression-like behavior. Half of rodent studies examining anxiety-like behavior (n = 13) noted adverse effects with SSRI exposure. A majority of studies of social behavior (n = 4) noted a decrease in sociability in SSRI exposed offspring. Human studies (n = 4) examining anxiety in the offspring showed no adverse effects of prenatal SSRI exposure. The outcome of one study suggested that children with autism were more likely to have a mother who was prescribed an SSRI during pregnancy. CONCLUSIONS Preclinical findings in rodents exposed to SSRIs during development point to an increase in depression- and anxiety-like behavior and alteration in social behaviors in the offspring, though both the methods used and the findings were not uniform. These data are not robust enough to discourage use of SSRIs during human pregnancy, particularly given the known adverse effects of maternal mental illness on pregnancy outcomes and infant neurodevelopment. Future research should focus on consistent animal models and prospective human studies with larger samples.
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Singh N, Gupta M, Trivedi CM, Singh MK, Li L, Epstein JA. Murine craniofacial development requires Hdac3-mediated repression of Msx gene expression. Dev Biol 2013; 377:333-44. [PMID: 23506836 DOI: 10.1016/j.ydbio.2013.03.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 03/04/2013] [Accepted: 03/09/2013] [Indexed: 01/11/2023]
Abstract
Craniofacial development is characterized by reciprocal interactions between neural crest cells and neighboring cell populations of ectodermal, endodermal and mesodermal origin. Various genetic pathways play critical roles in coordinating the development of cranial structures by modulating the growth, survival and differentiation of neural crest cells. However, the regulation of these pathways, particularly at the epigenomic level, remains poorly understood. Using murine genetics, we show that neural crest cells exhibit a requirement for the class I histone deacetylase Hdac3 during craniofacial development. Mice in which Hdac3 has been conditionally deleted in neural crest demonstrate fully penetrant craniofacial abnormalities, including microcephaly, cleft secondary palate and dental hypoplasia. Consistent with these abnormalities, we observe dysregulation of cell cycle genes and increased apoptosis in neural crest structures in mutant embryos. Known regulators of cell cycle progression and apoptosis in neural crest, including Msx1, Msx2 and Bmp4, are upregulated in Hdac3-deficient cranial mesenchyme. These results suggest that Hdac3 serves as a critical regulator of craniofacial morphogenesis, in part by repressing core apoptotic pathways in cranial neural crest cells.
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Affiliation(s)
- Nikhil Singh
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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Ohtsuka N, Badurek S, Busslinger M, Benes FM, Minichiello L, Rudolph U. GABAergic neurons regulate lateral ventricular development via transcription factor Pax5. Genesis 2013; 51:234-45. [PMID: 23349049 DOI: 10.1002/dvg.22370] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 01/09/2013] [Accepted: 01/14/2013] [Indexed: 12/27/2022]
Abstract
Postmortem studies have revealed a downregulation of the transcription factor Pax5 in GABAergic neurons in bipolar disorder, a neurodevelopmental disorder, raising the question whether Pax5 in GABAergic neurons has a role in normal brain development. In a genetic approach to study functions of Pax5 in GABAergic neurons, Pax5 was specifically deleted in GABAergic neurons from Pax5 floxed mice using a novel Gad1-Cre transgenic mouse line expressing Cre recombinase in Gad1-positive, that is, GABAergic neurons. Surprisingly, these mice developed a marked enlargement of the lateral ventricles at approximately 7 weeks of age, which was lethal within 1-2 weeks of its appearance. This hydrocephalus phenotype was observed in mice homozygous or heterozygous for the Pax5 conditional knockout, with a gene dosage-dependent penetrance. By QTL (quantitative trait loci) mapping, a 3.5 Mb segment on mouse chromosome 4 flanked by markers D4Mit237 and D4Mit214 containing approximately 92 genes including Pax5 has previously been linked to differences in lateral ventricular size. Our findings are consistent with Pax5 being a relevant gene underlying this QTL phenotype and demonstrate that Pax5 in GABAergic neurons is essential for normal ventricular development.
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Affiliation(s)
- Nobuhisa Ohtsuka
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, MA, USA
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Maekawa S, Kobayashi Y, Odagaki SI, Makino M, Kumanogoh H, Nakamura S, Morita M, Hayashi F. Interaction of NAP-22 with brain glutamic acid decarboxylase (GAD). Neurosci Lett 2013; 537:50-4. [PMID: 23376695 DOI: 10.1016/j.neulet.2013.01.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 01/07/2013] [Accepted: 01/21/2013] [Indexed: 10/27/2022]
Abstract
NAP-22 (also called BASP1 or CAP-23) is a neuron-enriched protein localized mainly in the synaptic vesicles and the synaptic plasma membrane. Biochemically, it is recovered in the lipid raft fraction. In order to understand the physiological function of the neuronal lipid raft, NAP-22 binding proteins were screened with a pull-down assay. Glutamic acid decarboxylase (GAD) was detected through LC-MS/MS, and Western blotting using a specific antibody confirmed the result. Two isoforms of GAD, GAD65 and GAD67, were expressed in bacteria as GST-fusion forms and the interaction with NAP-22 was confirmed in vitro. Partial co-localization of NAP-22 with GAD65 and GAD67 was also observed in cultured neurons. The binding showed no effect on the enzymatic activity of GAD65 and GAD67. These results hence suggest that NAP-22 could participate in the transport of GAD65 and GAD67 to the presynaptic termini and their retention on the synaptic vesicles as an anchoring protein.
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Affiliation(s)
- Shohei Maekawa
- Department of Biology, Graduate School of Science, Kobe University, Kobe 657-8501, Japan.
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Heldt SA, Mou L, Ressler KJ. In vivo knockdown of GAD67 in the amygdala disrupts fear extinction and the anxiolytic-like effect of diazepam in mice. Transl Psychiatry 2012; 2:e181. [PMID: 23149445 PMCID: PMC3565763 DOI: 10.1038/tp.2012.101] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In mammals, γ-aminobutyric acid (GABA) transmission in the amygdala is particularly important for controlling levels of fear and anxiety. Most GABA synthesis in the brain is catalyzed in inhibitory neurons from L-glutamic acid by the enzyme glutamic acid decarboxylase 67 (GAD67). In the current study, we sought to examine the acquisition and extinction of conditioned fear in mice with knocked down expression of the GABA synthesizing enzyme GAD67 in the amygdala using a lentiviral-based (LV) RNA interference strategy to locally induce loss-of-function. In vitro experiments revealed that our LV-siRNA-GAD67 construct diminished the expression of GAD67 as determined with western blot and fluorescent immunocytochemical analyses. In vivo experiments, in which male C57BL/6J mice received bilateral amygdala microinjections, revealed that LV-siRNA-GAD67 injections produce significant inhibition of endogenous GAD67 when compared with control injections. In contrast, no significant changes in GAD65 expression were detected in the amygdala, validating the specificity of LV knockdown. Behavioral experiments showed that LV knockdown of GAD67 results in a deficit in the extinction, but not the acquisition or retention, of fear as measured by conditioned freezing. GAD67 knockdown did not affect baseline locomotion or basal measures of anxiety as measured in open field apparatus. However, diminished GAD67 in the amygdala blunted the anxiolytic-like effect of diazepam (1.5 mg kg(-1)) as measured in the elevated plus maze. Together, these studies suggest that of GABAergic transmission in amygdala mediates the inhibition of conditioned fear and the anxiolytic-like effect of diazepam in adult mice.
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Affiliation(s)
- S A Heldt
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
| | - L Mou
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - K J Ressler
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA,Howard Hughes Medical Institute, Bethesda, MD, USA
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Kosaka Y, Kin H, Tatetsu M, Uema I, Takayama C. Distinct development of GABA system in the ventral and dorsal horns in the embryonic mouse spinal cord. Brain Res 2012; 1486:39-52. [PMID: 23044470 DOI: 10.1016/j.brainres.2012.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 09/25/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
Abstract
In the adult brain, γ-amino butyric acid (GABA) is an inhibitory neurotransmitter, whereas it acts as an excitatory transmitter in the immature brain, and may be involved in morphogenesis. In the present study, we immunohistochemically examined the developmental changes in GABA signaling in the embryonic mouse cervical spinal cord. Glutamic acid decarboxylase and GABA were markers for GABA neurons. Vesicular GABA transporter was a marker for GABAergic and glycinergic terminals. Potassium chloride cotransporter 2 was a marker for GABAergic inhibition. We found five points: (1) In the ventral part, GABA neurons were divided into three groups. The first differentiated group sent commissural axons after embryonic day 11 (E11), but disappeared or changed their transmitter by E15. The second and third differentiated groups were localized in the ventral horn after E12, and sent axons to the ipsilateral marginal zone. There was a distal-to-proximal gradient in varicosity formation in GABAergic axons and a superficial-to-deep gradient in GABAergic synapse formation in the ventral horn; (2) In the dorsal horn, GABA neurons were localized after E13, and synapses were diffusely formed after E15; (3) GABA may be excitatory for several days before synapses formation; (4) There was a ventral-to-dorsal gradient in the development of GABA signaling. The GABAergic inhibitory network may develop in the ventral horn between E15 and E17, and GABA may transiently play crucial roles in inhibitory regulation of the motor system in the mouse fetus; (5) GABA signaling continued to develop after birth, and GABAergic system diminished in the ventral horn.
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Affiliation(s)
- Yoshinori Kosaka
- Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 9030215, Japan
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Panzica-Kelly JM, Brannen KC, Ma Y, Zhang CX, Flint OP, Lehman-McKeeman LD, Augustine-Rauch KA. Establishment of a molecular embryonic stem cell developmental toxicity assay. Toxicol Sci 2012; 131:447-57. [PMID: 23042729 DOI: 10.1093/toxsci/kfs293] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mouse embryonic stem cell test (EST) is a 10-day screen for teratogenic potential developed to reduce animal use for embryotoxicity testing of chemicals (Spielmann, 2005; Spielmann et al., 1997). In this study, we used the cytotoxicity IC(50) values and transcriptional expression changes as primary endpoints in a shorter 4-day version of the EST, the molecular embryonic stem cell assay. Mouse D3 embryonic stem cells were used for cytotoxicity assessment (monolayers) or grown as embryoid bodies in low attachment plates for transcriptional profiling. Sixty-five compounds with known in vivo teratogenicity (33 teratogens and 32 nonteratogens) were evaluated to develop a model for classifying compounds with teratogenic potential. The expression of 12 developmentally regulated gene targets (nanog, fgf5, gsc, cd34, axin2, apln, chst7, lhx1, fgf8, sox17, foxa2, and cxcr4) was measured following exposure of embryoid bodies to a single compound concentration (0.1 × the cytotoxicity IC(20)) for 4 days. In the decision-tree model, compounds with IC(50) values < 22 µM were categorized as teratogens, whereas compounds in the two groups with IC(50) values between 22-200 µM and > 200 µM were categorized as teratogens if ≥ 8 and 12 genes, respectively, were deregulated by at least 10%. Forty-seven of 65 compounds of the training set were correctly identified (72% total concordance). In a test set of 12 additional compounds (5 teratogens, 7 nonteratogens), 10 were correctly classified by this approach (83% concordance). The false positive rate in the training and test sets was 24 and 0%, respectively, indicating that this assay has potential to identify teratogens.
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Kadriu B, Guidotti A, Chen Y, Grayson DR. DNA methyltransferases1 (DNMT1) and 3a (DNMT3a) colocalize with GAD67-positive neurons in the GAD67-GFP mouse brain. J Comp Neurol 2012; 520:1951-64. [PMID: 22134929 DOI: 10.1002/cne.23020] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DNA methylation is an epigenetic regulatory mechanism commonly associated with transcriptional silencing. DNA methyltransferases (DNMTs) are a family of related proteins that both catalyze the de novo formation of 5-methylcytosine and maintain these methylation marks in cell-specific patterns in virtually all mitotic cells of the body. In the adult brain, methylation occurs in progenitor cells of the neurogenic zones and in postmitotic neurons. Of the DNMTs, DNMT1 and DNMT3a are most highly expressed in postmitotic neurons. While it has been commonly thought all postmitotic neurons and glia express DNMTs at comparable levels, the coexpression of selected DNMTs with markers of distinct neurotransmitter phenotypes has not been previously examined in detail in the mouse. To this end, we analyzed the expression of DNMT1 and DNMT3a along with GAD67 in the brains of the glutamic acid decarboxylase67-enhanced green fluorescent protein (GAD67-GFP) knockin mice. After first confirming that GFP-immunopositive neurons were also GAD67-positive, we showed that in the motor cortex, piriform cortex, striatum, CA1 region of the hippocampus, dentate gyrus, and basolateral amygdala (BLA), GFP immunofluorescence coincided with the signal corresponding to DNMT1 and DNMT3a. A detailed examination of cortical neurons, showed that ≈30% of NeuN-immunopositive neurons were also DNMT1-positive. These data do not exclude the expression of DNMT1 or DNMT3a in glutamatergic neurons and glia. However, they suggest that their expression is low compared with the levels present in GABAergic neurons.
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Affiliation(s)
- Bashkim Kadriu
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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All-<I>trans</I> Retinoic Acid Promotes Cell Apoptosis Through Gamma Amino Butyric Acid Pathway in Murine Embryonic Palate Mesenchymal Cells. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2011.00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Blakely RD, Edwards RH. Vesicular and plasma membrane transporters for neurotransmitters. Cold Spring Harb Perspect Biol 2012; 4:a005595. [PMID: 22199021 PMCID: PMC3281572 DOI: 10.1101/cshperspect.a005595] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The regulated exocytosis that mediates chemical signaling at synapses requires mechanisms to coordinate the immediate response to stimulation with the recycling needed to sustain release. Two general classes of transporter contribute to release, one located on synaptic vesicles that loads them with transmitter, and a second at the plasma membrane that both terminates signaling and serves to recycle transmitter for subsequent rounds of release. Originally identified as the target of psychoactive drugs, these transport systems have important roles in transmitter release, but we are only beginning to understand their contribution to synaptic transmission, plasticity, behavior, and disease. Recent work has started to provide a structural basis for their activity, to characterize their trafficking and potential for regulation. The results indicate that far from the passive target of psychoactive drugs, neurotransmitter transporters undergo regulation that contributes to synaptic plasticity.
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Affiliation(s)
- Randy D Blakely
- Department of Pharmacology and Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-8548, USA
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Abstract
Nonsyndromic cleft lip and palate is a complex genetic disorder with variable phenotype, largely attributed to the interactions of the environment and multiple genes, each potentially having certain effects. Numerous genes have been reported in studies demonstrating associations and/or linkage of the cleft lip and palate phenotypes to alleles of microsatellite markers and single nucleotide polymorphisms within specific genes that regulate transcription factors, growth factors, cell signalling and detoxification metabolisms. Although the studies reporting these observations are compelling, most of them lack statistical power. This review compiles the evidence that supports linkage and associations to the various genetic loci and candidate genes. Whereas significant progress has been made in the field of cleft lip and palate genetics in the past decade, the role of the genes and genetic variations within the numerous candidate genes that have been found to associate with the expression of the orofacial cleft phenotype remain to be determined.
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Affiliation(s)
- Jyotsna Murthy
- Department of Plastic Surgery, Sri Ramachandra Medical College, Chennai, India
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Nakazawa K, Zsiros V, Jiang Z, Nakao K, Kolata S, Zhang S, Belforte JE. GABAergic interneuron origin of schizophrenia pathophysiology. Neuropharmacology 2011; 62:1574-83. [PMID: 21277876 DOI: 10.1016/j.neuropharm.2011.01.022] [Citation(s) in RCA: 349] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/11/2011] [Accepted: 01/13/2011] [Indexed: 12/16/2022]
Abstract
Hypofunction of N-methyl-d-aspartic acid-type glutamate receptors (NMDAR) induced by the systemic administration of NMDAR antagonists is well known to cause schizophrenia-like symptoms in otherwise healthy subjects. However, the brain areas or cell-types responsible for the emergence of these symptoms following NMDAR hypofunction remain largely unknown. One possibility, the so-called "GABAergic origin hypothesis," is that NMDAR hypofunction at GABAergic interneurons, in particular, is sufficient for schizophrenia-like effects. In one attempt to address this issue, transgenic mice were generated in which NMDARs were selectively deleted from cortical and hippocampal GABAergic interneurons, a majority of which were parvalbumin (PV)-positive. This manipulation triggered a constellation of phenotypes--from molecular and physiological to behavioral--resembling characteristics of human schizophrenia. Based on these results, and in conjunction with previous literature, we argue that during development, NMDAR hypofunction at cortical, PV-positive, fast-spiking interneurons produces schizophrenia-like effects. This review summarizes the data demonstrating that in schizophrenia, GABAergic (particularly PV-positive) interneurons are disrupted. PV-positive interneurons, many of which display a fast-spiking firing pattern, are critical not only for tight temporal control of cortical inhibition but also for the generation of synchronous membrane-potential gamma-band oscillations. We therefore suggest that in schizophrenia the specific ability of fast-spiking interneurons to control and synchronize disparate cortical circuits is disrupted and that this disruption may underlie many of the schizophrenia symptoms. We further argue that the high vulnerability of corticolimbic fast-spiking interneurons to genetic predispositions and to early environmental insults--including excitotoxicity and oxidative stress--might help to explain their significant contribution to the development of schizophrenia.
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Affiliation(s)
- Kazu Nakazawa
- Unit on Genetics of Cognition and Behavior, National Institute of Mental Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
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Saito K, Kakizaki T, Hayashi R, Nishimaru H, Furukawa T, Nakazato Y, Takamori S, Ebihara S, Uematsu M, Mishina M, Miyazaki JI, Yokoyama M, Konishi S, Inoue K, Fukuda A, Fukumoto M, Nakamura K, Obata K, Yanagawa Y. The physiological roles of vesicular GABA transporter during embryonic development: a study using knockout mice. Mol Brain 2010; 3:40. [PMID: 21190592 PMCID: PMC3023674 DOI: 10.1186/1756-6606-3-40] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 12/30/2010] [Indexed: 11/16/2022] Open
Abstract
Background The vesicular GABA transporter (VGAT) loads GABA and glycine from the neuronal cytoplasm into synaptic vesicles. To address functional importance of VGAT during embryonic development, we generated global VGAT knockout mice and analyzed them. Results VGAT knockouts at embryonic day (E) 18.5 exhibited substantial increases in overall GABA and glycine, but not glutamate, contents in the forebrain. Electrophysiological recordings from E17.5-18.5 spinal cord motoneurons demonstrated that VGAT knockouts presented no spontaneous inhibitory postsynaptic currents mediated by GABA and glycine. Histological examination of E18.5 knockout fetuses revealed reductions in the trapezius muscle, hepatic congestion and little alveolar spaces in the lung, indicating that the development of skeletal muscle, liver and lung in these mice was severely affected. Conclusion VGAT is fundamental for the GABA- and/or glycine-mediated transmission that supports embryonic development. VGAT knockout mice will be useful for further investigating the roles of VGAT in normal physiology and pathophysiologic processes.
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Affiliation(s)
- Kenzi Saito
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
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Chen Y, Dong E, Grayson DR. Analysis of the GAD1 promoter: trans-acting factors and DNA methylation converge on the 5' untranslated region. Neuropharmacology 2010; 60:1075-87. [PMID: 20869372 DOI: 10.1016/j.neuropharm.2010.09.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 09/10/2010] [Accepted: 09/16/2010] [Indexed: 12/22/2022]
Abstract
GAD67 corresponds to one of two enzymes that decarboxylates glutamate to produce γ-aminobutyric acid, the main inhibitory neurotransmitter in the mammalian central nervous system, hence defining the cellular phenotype of a diverse set of inhibitory interneurons of the brain. Reduced cortical GAD67 mRNA levels have consistently been reported in schizophrenia and bipolar disorder with psychosis. The human gene encoding GAD67, GAD1, is located on chromosome 2q31.1 and the transcriptional start site resides within a large CpG island that spans a region extending from upstream through the first exon. We have analyzed the GAD1 promoter using transient transfection analysis of upstream and downstream sequences in NT2 cells, a human neuroprogenitor cell line. Interestingly, results from these studies show that cis-acting regulatory elements are located downstream of the RNA start site and are in the region corresponding to the first exon. Trans-acting factors such as Pitx2 and the Dlx family of transcription factors are active in promoting downstream reporter expression even when all of the 5' flanking sequences are removed. However, those constructs that contain an internal deletion from +66 to +173 bp fail to support expression even when these factors are provided in trans. We have previously shown that the Class I histone deacetylase inhibitor MS-275 potently activates GAD1 mRNA expression in NT2 cells suggesting the possibility that the promoter is sensitive to drugs that induce chromatin remodeling. Using methyl DNA immuneprecipitation of MS-275-treated NT2 cells, we provide data showing that Class I HDAC inhibition mediated an increase in GAD1 expression and that this was accompanied by decreased GAD1 promoter methylation. Moreover, the reduced levels of GAD1 DNA methylation are highest in those regions proximal to the location of the in vitro defined cis-acting regulatory elements. Our data suggest that changes in promoter methylation associated with gene regulation are not random but overlap the locations of proximal cis-acting elements. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'.
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Affiliation(s)
- Ying Chen
- The Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois Chicago, 1601 W. Taylor St., Chicago, IL 60612, USA
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Kanaani J, Kolibachuk J, Martinez H, Baekkeskov S. Two distinct mechanisms target GAD67 to vesicular pathways and presynaptic clusters. ACTA ACUST UNITED AC 2010; 190:911-25. [PMID: 20805323 PMCID: PMC2935578 DOI: 10.1083/jcb.200912101] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The inhibitory neurotransmitter gamma-amino butyric acid (GABA) is synthesized by two isoforms of the enzyme glutamic acid decarboxylase (GAD): GAD65 and GAD67. Whereas GAD67 is constitutively active and produces >90% of GABA in the central nervous system, GAD65 is transiently activated and augments GABA levels for rapid modulation of inhibitory neurotransmission. Hydrophobic lipid modifications of the GAD65 protein target it to Golgi membranes and synaptic vesicles in neuroendocrine cells. In contrast, the GAD67 protein remains hydrophilic but has been shown to acquire membrane association by heterodimerization with GAD65. Here, we identify a second mechanism that mediates robust membrane anchoring, axonal targeting, and presynaptic clustering of GAD67 but that is independent of GAD65. This mechanism is abolished by a leucine-103 to proline mutation that changes the conformation of the N-terminal domain but does not affect the GAD65-dependent membrane anchoring of GAD67. Thus two distinct mechanisms target the constitutively active GAD67 to presynaptic clusters to facilitate accumulation of GABA for rapid delivery into synapses.
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Affiliation(s)
- Jamil Kanaani
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
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Fei H, Chow DM, Chen A, Romero-Calderón R, Ong WS, Ackerson LC, Maidment NT, Simpson JH, Frye MA, Krantz DE. Mutation of the Drosophila vesicular GABA transporter disrupts visual figure detection. ACTA ACUST UNITED AC 2010; 213:1717-30. [PMID: 20435823 DOI: 10.1242/jeb.036053] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The role of gamma amino butyric acid (GABA) release and inhibitory neurotransmission in regulating most behaviors remains unclear. The vesicular GABA transporter (VGAT) is required for the storage of GABA in synaptic vesicles and provides a potentially useful probe for inhibitory circuits. However, specific pharmacologic agents for VGAT are not available, and VGAT knockout mice are embryonically lethal, thus precluding behavioral studies. We have identified the Drosophila ortholog of the vesicular GABA transporter gene (which we refer to as dVGAT), immunocytologically mapped dVGAT protein expression in the larva and adult and characterized a dVGAT(minos) mutant allele. dVGAT is embryonically lethal and we do not detect residual dVGAT expression, suggesting that it is either a strong hypomorph or a null. To investigate the function of VGAT and GABA signaling in adult visual flight behavior, we have selectively rescued the dVGAT mutant during development. We show that reduced GABA release does not compromise the active optomotor control of wide-field pattern motion. Conversely, reduced dVGAT expression disrupts normal object tracking and figure-ground discrimination. These results demonstrate that visual behaviors are segregated by the level of GABA signaling in flies, and more generally establish dVGAT as a model to study the contribution of GABA release to other complex behaviors.
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Affiliation(s)
- Hao Fei
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Schubert T, Huckfeldt RM, Parker E, Campbell JE, Wong ROL. Assembly of the outer retina in the absence of GABA synthesis in horizontal cells. Neural Dev 2010; 5:15. [PMID: 20565821 PMCID: PMC2919532 DOI: 10.1186/1749-8104-5-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 06/18/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The inhibitory neurotransmitter gamma-amino-butyric acid (GABA) not only modulates excitability in the mature nervous system but also regulates neuronal differentiation and circuit development. Horizontal cells, a subset of interneurons in the outer retina, are transiently GABAergic during the period of cone photoreceptor synaptogenesis. In rodents, both horizontal cells and cone axonal terminals express GABAA receptors. To explore the possibility that transient GABA expression in mouse neonatal horizontal cells influences the structural development of synaptic connectivity in the outer retina, we examined a mutant in which expression of GAD67, the major synthesizing enzyme for GABA, is selectively knocked out in the retina. RESULTS Immunocytochemistry and electron microscopy revealed that the assembly of triad synapses involving cone axonal pedicles and the dendrites of horizontal and bipolar cells is unaffected in the mutant retina. Moreover, loss of GABA synthesis in the outer retina did not perturb the spatial distributions and cell densities of cones and horizontal cells. However, there were some structural alterations at the cellular level: the average size of horizontal cell dendritic clusters was larger in the mutant, and there was also a small but significant increase in cone photoreceptor pedicle area. Moreover, metabotropic glutamate receptor 6 (mGluR6) receptors on the dendrites of ON bipolar cells occupied a slightly larger proportion of the cone pedicle in the mutant. CONCLUSIONS Together, our analysis shows that transient GABA synthesis in horizontal cells is not critical for synapse assembly and axonal and dendritic lamination in the outer retina. However, pre- and postsynaptic structures are somewhat enlarged in the absence of GABA in the developing outer retina, providing for a modest increase in potential contact area between cone photoreceptors and their targets. These findings differ from previous results in which pharmacological blockade of GABAA receptors in the neonatal rabbit retina caused a reduction in cone numbers and led to a grossly disorganized outer retina.
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Affiliation(s)
- Timm Schubert
- Department of Biological Structure, University of Washington, School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA
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Oh WJ, Westmoreland JJ, Summers R, Condie BG. Cleft palate is caused by CNS dysfunction in Gad1 and Viaat knockout mice. PLoS One 2010; 5:e9758. [PMID: 20333300 PMCID: PMC2841638 DOI: 10.1371/journal.pone.0009758] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 03/01/2010] [Indexed: 12/22/2022] Open
Abstract
Background Previous studies have shown that disruption of GABA signaling in mice via mutations in the Gad1, Gabrb3 or Viaat genes leads to the development of non-neural developmental defects such as cleft palate. Studies of the Gabrb3 and Gad1 mutant mice have suggested that GABA function could be required either in the central nervous system or in the palate itself for normal palatogenesis. Methodology/Principal Findings To further examine the role of GABA signaling in palatogenesis we used three independent experimental approaches to test whether Gad1 or Viaat function is required in the fetal CNS for normal palate development. We used oral explant cultures to demonstrate that the Gad1 and Viaat mutant palates were able to undergo palatogenesis in culture, suggesting that there is no defect in the palate tissue itself in these mice. In a second series of experiments we found that the GABAA receptor agonist muscimol could rescue the cleft palate phenotype in Gad1 and Viaat mutant embryos. This suggested that normal multimeric GABAA receptors in the CNS were necessary for normal palatogenesis. In addition, we showed that CNS-specific inactivation of Gad1 was sufficient to disrupt palate development. Conclusions/Significance Our results are consistent with a role for Gad1 and Viaat in the central nervous system for normal development of the palate. We suggest that the alterations in GABA signaling lead to non-neural defects such as cleft palate as a secondary effect due to alterations in or elimination of fetal movements.
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Affiliation(s)
- Won-Jong Oh
- Developmental Biology Group, Department of Genetics, University of Georgia, Athens, Georgia, United States of America
- Institute of Molecular Medicine, Medical College of Georgia, Augusta, Georgia, United States of America
| | - Joby J. Westmoreland
- Institute of Molecular Medicine, Medical College of Georgia, Augusta, Georgia, United States of America
| | - Ryan Summers
- Developmental Biology Group, Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Brian G. Condie
- Developmental Biology Group, Department of Genetics, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Li F, Chen H, Lei CZ, Ren G, Wang J, Li ZJ, Wang JQ. Novel SNPs of the bovine GAD1/gad67 gene and their association with growth traits in three native Chinese cattle breeds. Mol Biol Rep 2010; 37:501-5. [PMID: 19728158 DOI: 10.1007/s11033-009-9699-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 07/29/2009] [Indexed: 11/28/2022]
Abstract
In this study, polymorphism in the exon 1, 2, 3, 4 and 5 of bovine GAD1 gene was detected by PCR-SSCP and DNA sequencing methods in 726 individuals from three Chinese cattle breeds. Two haplotypes (T and C) and three observed genotypes (TT, TC, and CC) were detected. The result of DNA sequence showed one mutations (T12345C) by comparisons with NC_007300: g.12345T>C. The mutation was at the exon 3, and was identified a missense mutation Phe (TTT)>Leu (CTT) at position 51 (p.F51L). Polymorphism of the GAD1 gene was shown to be associated with growth traits in the Nanyang breed. The SNP in the bovine GAD1 gene had significant effects on body length, body weight, heart girth, and average daily gain at 24 months (P < 0.05). Therefore, these results suggest that the GAD1 gene is a strong candidate gene that affects growth traits in cattle.
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Affiliation(s)
- F Li
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A & F University, Yangling, Shaanxi, People's Republic of China
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Blednov YA, Walker DL, Iyer SV, Homanics G, Harris AR. Mice lacking Gad2 show altered behavioral effects of ethanol, flurazepam and gabaxadol. Addict Biol 2010; 15:45-61. [PMID: 20002022 PMCID: PMC3038569 DOI: 10.1111/j.1369-1600.2009.00186.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Gamma-aminobutyric acid (GABA) is synthesized in brain by two isoforms of glutamic acid decarboxylase (Gad), Gad1 and Gad2. Gad1 provides most of the GABA in brain, but Gad2 can be rapidly activated in times of high GABA demand. Mice lacking Gad2 are viable whereas deletion of Gad1 is lethal. We produced null mutant mice for Gad2 on three different genetic backgrounds: predominantly C57BL/6J and one or two generations of backcrossing to 129S1/SvimJ (129N1, 129N2). We used these mice to determine if actions of alcohol are regulated by synthesis of GABA from this isoform. We also studied behavioral responses to a benzodiazepine (flurazepam) and a GABAA receptor agonist (gabaxadol). Deletion of Gad2 increased ethanol palatability and intake and slightly reduced the severity of ethanol-induced withdrawal, but these effects depended strongly on genetic background. Mutant mice on the 129N2 background showed the above three ethanol behavioral phenotypes, but the C57BL/6J inbred background did not show any of these phenotypes. Effects on ethanol consumption also depended on the test as the mutation did not alter consumption in limited access models. Deletion of Gad2 reduced the effect of flurazepam on motor incoordination and increased the effect of extrasynaptic GABAA receptor agonist gabaxadol without changing the duration of loss of righting reflex produced by these drugs. These results are consistent with earlier proposals that deletion of Gad2 (on 129N2 background) reduces synaptic GABA but also suggest changes in extrasynaptic receptor function.
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Affiliation(s)
- Yuri A. Blednov
- University of Texas, Waggoner Center for Alcohol and Addiction Research, USA
| | - Danielle L. Walker
- University of Texas, Waggoner Center for Alcohol and Addiction Research, USA
| | - Sangeetha V. Iyer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, USA
| | - Gregg Homanics
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, USA,Department of Anesthesiology, University of Pittsburgh, USA
| | - Adron R. Harris
- University of Texas, Waggoner Center for Alcohol and Addiction Research, USA
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Yu W, Serrano M, Miguel SS, Ruest LB, Svoboda KK. Cleft lip and palate genetics and application in early embryological development. Indian J Plast Surg 2009; 42 Suppl:S35-50. [PMID: 19884679 PMCID: PMC2825058 DOI: 10.4103/0970-0358.57185] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The development of the head involves the interaction of several cell populations and coordination of cell signalling pathways, which when disrupted can cause defects such as facial clefts. This review concentrates on genetic contributions to facial clefts with and without cleft palate (CP). An overview of early palatal development with emphasis on muscle and bone development is blended with the effects of environmental insults and known genetic mutations that impact human palatal development. An extensive table of known genes in syndromic and non-syndromic CP, with or without cleft lip (CL), is provided. We have also included some genes that have been identified in environmental risk factors for CP/L. We include primary and review references on this topic.
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Affiliation(s)
- Wenli Yu
- Department of Biomedical Sciences, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, TX 75246
| | - Maria Serrano
- Department of Biomedical Sciences, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, TX 75246
| | - Symone San Miguel
- Department of Biomedical Sciences, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, TX 75246
| | - L. Bruno Ruest
- Department of Biomedical Sciences, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, TX 75246
| | - Kathy K.H. Svoboda
- Department of Biomedical Sciences, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, TX 75246
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