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Terry AV, Jones K, Bertrand D. Nicotinic acetylcholine receptors in neurological and psychiatric diseases. Pharmacol Res 2023; 191:106764. [PMID: 37044234 DOI: 10.1016/j.phrs.2023.106764] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/30/2023] [Accepted: 04/07/2023] [Indexed: 04/14/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that are widely distributed both pre- and post-synaptically in the mammalian brain. By modulating cation flux across cell membranes, neuronal nAChRs regulate neuronal excitability and the release of a variety of neurotransmitters to influence multiple physiologic and behavioral processes including synaptic plasticity, motor function, attention, learning and memory. Abnormalities of neuronal nAChRs have been implicated in the pathophysiology of neurologic disorders including Alzheimer's disease, Parkinson's disease, epilepsy, and Tourette´s syndrome, as well as psychiatric disorders including schizophrenia, depression, and anxiety. The potential role of nAChRs in a particular illness may be indicated by alterations in the expression of nAChRs in relevant brain regions, genetic variability in the genes encoding for nAChR subunit proteins, and/or clinical or preclinical observations where specific ligands showed a therapeutic effect. Over the past 25 years, extensive preclinical and some early clinical evidence suggested that ligands at nAChRs might have therapeutic potential for neurologic and psychiatric disorders. However, to date the only approved indications for nAChR ligands are smoking cessation and the treatment of dry eye disease. It has been argued that progress in nAChR drug discovery has been limited by translational gaps between the preclinical models and the human disease as well as unresolved questions regarding the pharmacological goal (i.e., agonism, antagonism or receptor desensitization) depending on the disease.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912.
| | - Keri Jones
- Educational Innovation Institute, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland
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2
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Becchetti A, Grandi LC, Cerina M, Amadeo A. Nicotinic acetylcholine receptors and epilepsy. Pharmacol Res 2023; 189:106698. [PMID: 36796465 DOI: 10.1016/j.phrs.2023.106698] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/04/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023]
Abstract
Despite recent advances in understanding the causes of epilepsy, especially the genetic, comprehending the biological mechanisms that lead to the epileptic phenotype remains difficult. A paradigmatic case is constituted by the epilepsies caused by altered neuronal nicotinic acetylcholine receptors (nAChRs), which exert complex physiological functions in mature as well as developing brain. The ascending cholinergic projections exert potent control of forebrain excitability, and wide evidence implicates nAChR dysregulation as both cause and effect of epileptiform activity. First, tonic-clonic seizures are triggered by administration of high doses of nicotinic agonists, whereas non-convulsive doses have kindling effects. Second, sleep-related epilepsy can be caused by mutations on genes encoding nAChR subunits widely expressed in the forebrain (CHRNA4, CHRNB2, CHRNA2). Third, in animal models of acquired epilepsy, complex time-dependent alterations in cholinergic innervation are observed following repeated seizures. Heteromeric nAChRs are central players in epileptogenesis. Evidence is wide for autosomal dominant sleep-related hypermotor epilepsy (ADSHE). Studies of ADSHE-linked nAChR subunits in expression systems suggest that the epileptogenic process is promoted by overactive receptors. Investigation in animal models of ADSHE indicates that expression of mutant nAChRs can lead to lifelong hyperexcitability by altering i) the function of GABAergic populations in the mature neocortex and thalamus, ii) synaptic architecture during synaptogenesis. Understanding the balance of the epileptogenic effects in adult and developing networks is essential to plan rational therapy at different ages. Combining this knowledge with a deeper understanding of the functional and pharmacological properties of individual mutations will advance precision and personalized medicine in nAChR-dependent epilepsy.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy.
| | - Laura Clara Grandi
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy.
| | - Marta Cerina
- Department of Biotechnology and Biosciences, and NeuroMI (Milan Center of Neuroscience), University of Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy.
| | - Alida Amadeo
- Department of Biosciences, University of Milano, Via Celoria 26, Milano 20133, Italy.
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3
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Liaci C, Camera M, Zamboni V, Sarò G, Ammoni A, Parmigiani E, Ponzoni L, Hidisoglu E, Chiantia G, Marcantoni A, Giustetto M, Tomagra G, Carabelli V, Torelli F, Sala M, Yanagawa Y, Obata K, Hirsch E, Merlo GR. Loss of ARHGAP15 affects the directional control of migrating interneurons in the embryonic cortex and increases susceptibility to epilepsy. Front Cell Dev Biol 2022; 10:875468. [PMID: 36568982 PMCID: PMC9774038 DOI: 10.3389/fcell.2022.875468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 11/07/2022] [Indexed: 12/13/2022] Open
Abstract
GTPases of the Rho family are components of signaling pathways linking extracellular signals to the control of cytoskeleton dynamics. Among these, RAC1 plays key roles during brain development, ranging from neuronal migration to neuritogenesis, synaptogenesis, and plasticity. RAC1 activity is positively and negatively controlled by guanine nucleotide exchange factors (GEFs), guanosine nucleotide dissociation inhibitors (GDIs), and GTPase-activating proteins (GAPs), but the specific role of each regulator in vivo is poorly known. ARHGAP15 is a RAC1-specific GAP expressed during development in a fraction of migrating cortical interneurons (CINs) and in the majority of adult CINs. During development, loss of ARHGAP15 causes altered directionality of the leading process of tangentially migrating CINs, along with altered morphology in vitro. Likewise, time-lapse imaging of embryonic CINs revealed a poorly coordinated directional control during radial migration, possibly due to a hyper-exploratory behavior. In the adult cortex, the observed defects lead to subtle alteration in the distribution of CALB2-, SST-, and VIP-positive interneurons. Adult Arhgap15-knock-out mice also show reduced CINs intrinsic excitability, spontaneous subclinical seizures, and increased susceptibility to the pro-epileptic drug pilocarpine. These results indicate that ARHGAP15 imposes a fine negative regulation on RAC1 that is required for morphological maturation and directional control during CIN migration, with consequences on their laminar distribution and inhibitory function.
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Affiliation(s)
- Carla Liaci
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Mattia Camera
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Valentina Zamboni
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Gabriella Sarò
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Alessandra Ammoni
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | | | - Luisa Ponzoni
- Neuroscience Institute, Consiglio Nazionale Ricerche, Milan, Italy
| | - Enis Hidisoglu
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | - Giuseppe Chiantia
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | - Maurizio Giustetto
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Giulia Tomagra
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | | | - Federico Torelli
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany,Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Mariaelvina Sala
- Neuroscience Institute, Consiglio Nazionale Ricerche, Milan, Italy
| | - Yuchio Yanagawa
- Department of Genetic Behavioral Neuroscience, Gunma University, Maebashi, Japan
| | | | - Emilio Hirsch
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Giorgio R. Merlo
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy,*Correspondence: Giorgio R. Merlo,
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Meneghini S, Modena D, Colombo G, Coatti A, Milani N, Madaschi L, Amadeo A, Becchetti A. The β2V287L nicotinic subunit linked to sleep-related epilepsy differently affects fast-spiking and regular spiking somatostatin-expressing neurons in murine prefrontal cortex. Prog Neurobiol 2022; 214:102279. [DOI: 10.1016/j.pneurobio.2022.102279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 04/02/2022] [Accepted: 04/28/2022] [Indexed: 12/01/2022]
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5
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Beretta S, Gritti L, Ponzoni L, Scalmani P, Mantegazza M, Sala M, Verpelli C, Sala C. Rescuing epileptic and behavioral alterations in a Dravet syndrome mouse model by inhibiting eukaryotic elongation factor 2 kinase (eEF2K). Mol Autism 2022; 13:1. [PMID: 34980259 PMCID: PMC8722032 DOI: 10.1186/s13229-021-00484-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/23/2021] [Indexed: 11/30/2022] Open
Abstract
Background Dravet Syndrome is a severe childhood pharmaco-resistant epileptic disorder mainly caused by mutations in the SCN1A gene, which encodes for the α1 subunit of the type I voltage-gated sodium channel (NaV1.1), that causes imbalance between excitation and inhibition in the brain. We recently found that eEF2K knock out mice displayed enhanced GABAergic transmission and tonic inhibition and were less susceptible to epileptic seizures. Thus, we investigated the effect of inhibition of eEF2K on the epileptic and behavioral phenotype of Scn1a ± mice, a murine model of Dravet Syndrome. Methods To elucidate the role of eEF2K pathway in the etiopathology of Dravet syndrome we generated a new mouse model deleting the eEF2K gene in Scn1a ± mice. By crossing Scn1a ± mice with eEF2K−/− mice we obtained the three main genotypes needed for our studies, Scn1a+/+ eEF2K+/+ (WT mice), Scn1a ± eEF2K+/+ mice (Scn1a ± mice) and Scn1a ± eEF2K−/− mice, that were fully characterized for EEG and behavioral phenotype. Furthermore, we tested the ability of a pharmacological inhibitor of eEF2K in rescuing EEG alterations of the Scn1a ± mice. Results We showed that the activity of eEF2K/eEF2 pathway was enhanced in Scn1a ± mice. Then, we demonstrated that both genetic deletion and pharmacological inhibition of eEF2K were sufficient to ameliorate the epileptic phenotype of Scn1a ± mice. Interestingly we also found that motor coordination defect, memory impairments, and stereotyped behavior of the Scn1a ± mice were reverted by eEF2K deletion. The analysis of spontaneous inhibitory postsynaptic currents (sIPSCs) suggested that the rescue of the pathological phenotype was driven by the potentiation of GABAergic synapses. Limitations Even if we found that eEF2K deletion was able to increase inhibitory synapses function, the molecular mechanism underlining the inhibition of eEF2K/eEF2 pathway in rescuing epileptic and behavioral alterations in the Scn1a ± needs further investigations. Conclusions Our data indicate that pharmacological inhibition of eEF2K could represent a novel therapeutic intervention for treating epilepsy and related comorbidities in the Dravet syndrome. Supplementary Information The online version contains supplementary material available at 10.1186/s13229-021-00484-0.
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Affiliation(s)
- Stefania Beretta
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Laura Gritti
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Luisa Ponzoni
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Paolo Scalmani
- L'Unità Operativa Complessa di Epilettologia Clinica e Sperimentale, Foundation Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Neurological Institute Carlo Besta, 20133, Milan, Italy
| | - Massimo Mantegazza
- CNRS UMR 7275, Institut National de La Santé Et de La Recherche Médicale, LabEx ICST, Institute of Molecular and Cellular Pharmacology (IPMC), Université Côte d'Azur (UCA), 06560, Valbonne-Sophia Antipolis, France
| | - Mariaelvina Sala
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Chiara Verpelli
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy.
| | - Carlo Sala
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy.
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Okada M. Can rodent models elucidate the pathomechanisms of genetic epilepsy? Br J Pharmacol 2021; 179:1620-1639. [PMID: 33689168 PMCID: PMC9291625 DOI: 10.1111/bph.15443] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/03/2021] [Accepted: 03/04/2021] [Indexed: 12/31/2022] Open
Abstract
Autosomal dominant sleep-related hypermotor epilepsy (ADSHE; previously autosomal dominant nocturnal frontal lobe epilepsy, ADNFLE), originally reported in 1994, was the first distinct genetic epilepsy shown to be caused by CHNRA4 mutation. In the past two decades, we have identified several functional abnormalities of mutant ion channels and their associated transmissions using several experiments involving single-cell and genetic animal (rodent) models. Currently, epileptologists understand that functional abnormalities underlying epileptogenesis/ictogenesis in humans and rodents are more complicated than previously believed and that the function of mutant molecules alone cannot contribute to the development of epileptogenesis/ictogenesis but play important roles in the development of epileptogenesis/ictogenesis through formation of abnormalities in various other transmission systems before epilepsy onset. Based on our recent findings using genetic rat ADSHE models, harbouring Chrna4 mutant, corresponding to human S284L-mutant CRHNA4, this review proposes a hypothesis associated with tripartite synaptic transmission in ADSHE pathomechanisms induced by mutant ACh receptors.
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Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan
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Nicotinic Receptors in Sleep-Related Hypermotor Epilepsy: Pathophysiology and Pharmacology. Brain Sci 2020; 10:brainsci10120907. [PMID: 33255633 PMCID: PMC7761363 DOI: 10.3390/brainsci10120907] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/19/2020] [Accepted: 11/21/2020] [Indexed: 12/12/2022] Open
Abstract
Sleep-related hypermotor epilepsy (SHE) is characterized by hyperkinetic focal seizures, mainly arising in the neocortex during non-rapid eye movements (NREM) sleep. The familial form is autosomal dominant SHE (ADSHE), which can be caused by mutations in genes encoding subunits of the neuronal nicotinic acetylcholine receptor (nAChR), Na+-gated K+ channels, as well as non-channel signaling proteins, such as components of the gap activity toward rags 1 (GATOR1) macromolecular complex. The causative genes may have different roles in developing and mature brains. Under this respect, nicotinic receptors are paradigmatic, as different pathophysiological roles are exerted by distinct nAChR subunits in adult and developing brains. The widest evidence concerns α4 and β2 subunits. These participate in heteromeric nAChRs that are major modulators of excitability in mature neocortical circuits as well as regulate postnatal synaptogenesis. However, growing evidence implicates mutant α2 subunits in ADSHE, which poses interpretive difficulties as very little is known about the function of α2-containing (α2*) nAChRs in the human brain. Planning rational therapy must consider that pharmacological treatment could have different effects on synaptic maturation and adult excitability. We discuss recent attempts towards precision medicine in the mature brain and possible approaches to target developmental stages. These issues have general relevance in epilepsy treatment, as the pathogenesis of genetic epilepsies is increasingly recognized to involve developmental alterations.
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Neuroimaging Biomarkers of Experimental Epileptogenesis and Refractory Epilepsy. Int J Mol Sci 2019; 20:ijms20010220. [PMID: 30626103 PMCID: PMC6337422 DOI: 10.3390/ijms20010220] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 11/17/2022] Open
Abstract
This article provides an overview of neuroimaging biomarkers in experimental epileptogenesis and refractory epilepsy. Neuroimaging represents a gold standard and clinically translatable technique to identify neuropathological changes in epileptogenesis and longitudinally monitor its progression after a precipitating injury. Neuroimaging studies, along with molecular studies from animal models, have greatly improved our understanding of the neuropathology of epilepsy, such as the hallmark hippocampus sclerosis. Animal models are effective for differentiating the different stages of epileptogenesis. Neuroimaging in experimental epilepsy provides unique information about anatomic, functional, and metabolic alterations linked to epileptogenesis. Recently, several in vivo biomarkers for epileptogenesis have been investigated for characterizing neuronal loss, inflammation, blood-brain barrier alterations, changes in neurotransmitter density, neurovascular coupling, cerebral blood flow and volume, network connectivity, and metabolic activity in the brain. Magnetic resonance imaging (MRI) is a sensitive method for detecting structural and functional changes in the brain, especially to identify region-specific neuronal damage patterns in epilepsy. Positron emission tomography (PET) and single-photon emission computerized tomography are helpful to elucidate key functional alterations, especially in areas of brain metabolism and molecular patterns, and can help monitor pathology of epileptic disorders. Multimodal procedures such as PET-MRI integrated systems are desired for refractory epilepsy. Validated biomarkers are warranted for early identification of people at risk for epilepsy and monitoring of the progression of medical interventions.
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Indurthi DC, Qudah T, Liao VW, Ahring PK, Lewis TM, Balle T, Chebib M, Absalom NL. Revisiting autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) mutations in the nicotinic acetylcholine receptor reveal an increase in efficacy regardless of stochiometry. Pharmacol Res 2019; 139:215-227. [DOI: 10.1016/j.phrs.2018.11.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 11/21/2018] [Accepted: 11/21/2018] [Indexed: 12/22/2022]
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Kumar J, Solaiman A, Mahakkanukrauh P, Mohamed R, Das S. Sleep Related Epilepsy and Pharmacotherapy: An Insight. Front Pharmacol 2018; 9:1088. [PMID: 30319421 PMCID: PMC6171479 DOI: 10.3389/fphar.2018.01088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/07/2018] [Indexed: 01/26/2023] Open
Abstract
In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.
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Affiliation(s)
- Jaya Kumar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Amro Solaiman
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Pasuk Mahakkanukrauh
- Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Excellence Centre in Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Rashidi Mohamed
- Department of Familty Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Srijit Das
- Department of Anatomy, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
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Amadeo A, Coatti A, Aracri P, Ascagni M, Iannantuoni D, Modena D, Carraresi L, Brusco S, Meneghini S, Arcangeli A, Pasini ME, Becchetti A. Postnatal Changes in K +/Cl - Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy. Neuroscience 2018; 386:91-107. [PMID: 29949744 DOI: 10.1016/j.neuroscience.2018.06.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 12/13/2022]
Abstract
The Na+/K+/Cl- cotransporter-1 (NKCC1) and the K+/Cl- cotransporter-2 (KCC2) set the transmembrane Cl- gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant β2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing β2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying β2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing β2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of β2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits.
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Affiliation(s)
- Alida Amadeo
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Aurora Coatti
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Patrizia Aracri
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Miriam Ascagni
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Davide Iannantuoni
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Debora Modena
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Laura Carraresi
- Dival Toscana Srl, Via Madonna del Piano, 6 - 50019 Sesto Fiorentino, Firenze, Italy.
| | - Simone Brusco
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Simone Meneghini
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Firenze, Italy.
| | - Maria Enrica Pasini
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
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Reid CA, Rollo B, Petrou S, Berkovic SF. Can mutation‐mediated effects occurring early in development cause long‐term seizure susceptibility in genetic generalized epilepsies? Epilepsia 2018; 59:915-922. [DOI: 10.1111/epi.14077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Christopher Alan Reid
- The Florey Institute for Neuroscience and Mental Health The University of Melbourne Parkville Victoria Australia
| | - Ben Rollo
- The Florey Institute for Neuroscience and Mental Health The University of Melbourne Parkville Victoria Australia
| | - Steven Petrou
- The Florey Institute for Neuroscience and Mental Health The University of Melbourne Parkville Victoria Australia
| | - Samuel F. Berkovic
- Department of Medicine Epilepsy Research Centre Austin Health University of Melbourne Heidelberg Victoria Australia
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13
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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14
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Heise C, Taha E, Murru L, Ponzoni L, Cattaneo A, Guarnieri FC, Montani C, Mossa A, Vezzoli E, Ippolito G, Zapata J, Barrera I, Ryazanov AG, Cook J, Poe M, Stephen MR, Kopanitsa M, Benfante R, Rusconi F, Braida D, Francolini M, Proud CG, Valtorta F, Passafaro M, Sala M, Bachi A, Verpelli C, Rosenblum K, Sala C. eEF2K/eEF2 Pathway Controls the Excitation/Inhibition Balance and Susceptibility to Epileptic Seizures. Cereb Cortex 2017; 27:2226-2248. [PMID: 27005990 PMCID: PMC5963824 DOI: 10.1093/cercor/bhw075] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Alterations in the balance of inhibitory and excitatory synaptic transmission have been implicated in the pathogenesis of neurological disorders such as epilepsy. Eukaryotic elongation factor 2 kinase (eEF2K) is a highly regulated, ubiquitous kinase involved in the control of protein translation. Here, we show that eEF2K activity negatively regulates GABAergic synaptic transmission. Indeed, loss of eEF2K increases GABAergic synaptic transmission by upregulating the presynaptic protein Synapsin 2b and α5-containing GABAA receptors and thus interferes with the excitation/inhibition balance. This cellular phenotype is accompanied by an increased resistance to epilepsy and an impairment of only a specific hippocampal-dependent fear conditioning. From a clinical perspective, our results identify eEF2K as a potential novel target for antiepileptic drugs, since pharmacological and genetic inhibition of eEF2K can revert the epileptic phenotype in a mouse model of human epilepsy.
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Affiliation(s)
| | - Elham Taha
- Sagol Department of Neurobiology and
- Center for Gene Manipulation in the Brain, Natural Science Faculty, University of Haifa, Haifa, Israel
| | - Luca Murru
- CNR Neuroscience Institute, Milan, Italy
| | - Luisa Ponzoni
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | | | - Fabrizia C. Guarnieri
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | | | | | - Elena Vezzoli
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | | | | | - Iliana Barrera
- Sagol Department of Neurobiology and
- Center for Gene Manipulation in the Brain, Natural Science Faculty, University of Haifa, Haifa, Israel
| | - Alexey G. Ryazanov
- The Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - James Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Michael Poe
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Michael Rajesh Stephen
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Maksym Kopanitsa
- Synome, Babraham Research Campus, Cambridge CB22 3AT, UK
- Charles River Discovery Research Services, 70210 Kuopio, Finland
| | - Roberta Benfante
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Francesco Rusconi
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Daniela Braida
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Maura Francolini
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Christopher G. Proud
- University of Southampton, Centre for Biological Sciences, Southampton SO17 1BJ, UK
- South Australian Health and Medical Research Institute and University of Adelaide, Adelaide, Australia
| | - Flavia Valtorta
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Maria Passafaro
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Mariaelvina Sala
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Angela Bachi
- IFOM-FIRC Institute of Molecular Oncology, Milan, Italy
| | - Chiara Verpelli
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Kobi Rosenblum
- Sagol Department of Neurobiology and
- Center for Gene Manipulation in the Brain, Natural Science Faculty, University of Haifa, Haifa, Israel
| | - Carlo Sala
- CNR Neuroscience Institute, Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
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15
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Takayanagi-Kiya S, Zhou K, Jin Y. Release-dependent feedback inhibition by a presynaptically localized ligand-gated anion channel. eLife 2016; 5:e21734. [PMID: 27782882 PMCID: PMC5102579 DOI: 10.7554/elife.21734] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/25/2016] [Indexed: 12/16/2022] Open
Abstract
Presynaptic ligand-gated ion channels (LGICs) have long been proposed to affect neurotransmitter release and to tune the neural circuit activity. However, the understanding of their in vivo physiological action remains limited, partly due to the complexity in channel types and scarcity of genetic models. Here we report that C. elegans LGC-46, a member of the Cys-loop acetylcholine (ACh)-gated chloride (ACC) channel family, localizes to presynaptic terminals of cholinergic motor neurons and regulates synaptic vesicle (SV) release kinetics upon evoked release of acetylcholine. Loss of lgc-46 prolongs evoked release, without altering spontaneous activity. Conversely, a gain-of-function mutation of lgc-46 shortens evoked release to reduce synaptic transmission. This inhibition of presynaptic release requires the anion selectivity of LGC-46, and can ameliorate cholinergic over-excitation in a C. elegans model of excitation-inhibition imbalance. These data demonstrate a novel mechanism of presynaptic negative feedback in which an anion-selective LGIC acts as an auto-receptor to inhibit SV release.
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Affiliation(s)
- Seika Takayanagi-Kiya
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Keming Zhou
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
- Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
- Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
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16
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Nichols WA, Henderson BJ, Marotta CB, Yu CY, Richards C, Dougherty DA, Lester HA, Cohen BN. Mutation Linked to Autosomal Dominant Nocturnal Frontal Lobe Epilepsy Reduces Low-Sensitivity α4β2, and Increases α5α4β2, Nicotinic Receptor Surface Expression. PLoS One 2016; 11:e0158032. [PMID: 27336596 PMCID: PMC4918917 DOI: 10.1371/journal.pone.0158032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/09/2016] [Indexed: 11/24/2022] Open
Abstract
A number of mutations in α4β2-containing (α4β2*) nicotinic acetylcholine (ACh) receptors (nAChRs) are linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), including one in the β2 subunit called β2V287L. Two α4β2* subtypes with different subunit stoichiometries and ACh sensitivities co-exist in the brain, a high-sensitivity subtype with (α4)2(β2)3 subunit stoichiometry and a low-sensitivity subtype with (α4)3(β2)2 stoichiometry. The α5 nicotinic subunit also co-assembles with α4β2 to form a high-sensitivity α5α4β2 nAChR. Previous studies suggest that the β2V287L mutation suppresses low-sensitivity α4β2* nAChR expression in a knock-in mouse model and also that α5 co-expression improves the surface expression of ADNFLE mutant nAChRs in a cell line. To test these hypotheses further, we expressed mutant and wild-type (WT) nAChRs in oocytes and mammalian cell lines, and measured the effects of the β2V287L mutation on surface receptor expression and the ACh response using electrophysiology, a voltage-sensitive fluorescent dye, and superecliptic pHluorin (SEP). The β2V287L mutation reduced the EC50 values of high- and low-sensitivity α4β2 nAChRs expressed in Xenopus oocytes for ACh by a similar factor and suppressed low-sensitivity α4β2 expression. In contrast, it did not affect the EC50 of α5α4β2 nAChRs for ACh. Measurements of the ACh responses of WT and mutant nAChRs expressed in mammalian cell lines using a voltage-sensitive fluorescent dye and whole-cell patch-clamping confirm the oocyte data. They also show that, despite reducing the maximum response, β2V287L increased the α4β2 response to a sub-saturating ACh concentration (1 μM). Finally, imaging SEP-tagged α5, α4, β2, and β2V287L subunits showed that β2V287L reduced total α4β2 nAChR surface expression, increased the number of β2 subunits per α4β2 receptor, and increased surface α5α4β2 nAChR expression. Thus, the β2V287L mutation alters the subunit composition and sensitivity of α4β2 nAChRs, and increases α5α4β2 surface expression.
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Affiliation(s)
- Weston A Nichols
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Brandon J Henderson
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Christopher B Marotta
- Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Caroline Y Yu
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Chris Richards
- Department of Chemistry, University of Kentucky, Lexington, KY, United States of America
| | - Dennis A Dougherty
- Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Henry A Lester
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Bruce N Cohen
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
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17
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Boillot M, Baulac S. Genetic models of focal epilepsies. J Neurosci Methods 2016; 260:132-43. [DOI: 10.1016/j.jneumeth.2015.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 01/06/2023]
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18
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Spontaneous epileptic seizures in transgenic rats harboring a human ADNFLE missense mutation in the β2-subunit of the nicotinic acetylcholine receptor. Neurosci Res 2015; 100:46-54. [PMID: 26091610 DOI: 10.1016/j.neures.2015.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/05/2015] [Accepted: 06/09/2015] [Indexed: 11/22/2022]
Abstract
We generated a transgenic rat strain with a missense mutation in V286L (V286L-TG), in the gene encoding the neuronal nicotinic acetylcholine receptor β2 subunit (CHRNB2) found in patients with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). To confirm that V286L-TG rats exhibit seizures similar to those observed in humans, gene expression patterns and behavioral phenotypes were analyzed. In situ hybridization using a V286L Chrnb2-selective probe indicated that the transgene was expressed at higher levels in the cortex, hippocampus, and cerebellum of V286L-TG than wild-type littermates (non-TG). Spontaneous epileptic seizures with ictal discharges in electroencephalograms were detected in 45% of V286L-TG rats and the frequency of seizures was 0.73 times a week. This seizure type is similar to "paroxysmal arousals" that are observed in human ADNFLE. V286L-TG rats displayed nicotine-induced abnormal motor activity including seizures in comparison to non-TGs. Response time following nicotine administration occurred faster in V286L-TG than in non-TG rats. V286L-TG rats demonstrated spontaneous epileptic seizures, which are similar to human ADNFLE, and also showed a higher sensitivity to nicotine administration. Thus, the V286L-TG rat model could be a valuable tool for developing novel mechanism-driven treatment strategies for epilepsy and provide a better understanding of ADNFLE.
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19
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Becchetti A, Aracri P, Meneghini S, Brusco S, Amadeo A. The role of nicotinic acetylcholine receptors in autosomal dominant nocturnal frontal lobe epilepsy. Front Physiol 2015; 6:22. [PMID: 25717303 PMCID: PMC4324070 DOI: 10.3389/fphys.2015.00022] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/14/2015] [Indexed: 11/22/2022] Open
Abstract
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a focal epilepsy with attacks typically arising in the frontal lobe during non-rapid eye movement (NREM) sleep. It is characterized by clusters of complex and stereotyped hypermotor seizures, frequently accompanied by sudden arousals. Cognitive and psychiatric symptoms may be also observed. Approximately 12% of the ADNFLE families carry mutations on genes coding for subunits of the heteromeric neuronal nicotinic receptors (nAChRs). This is consistent with the widespread expression of these receptors, particularly the α4β2* subtype, in the neocortex and thalamus. However, understanding how mutant nAChRs lead to partial frontal epilepsy is far from being straightforward because of the complexity of the cholinergic regulation in both developing and mature brains. The relation with the sleep-waking cycle must be also explained. We discuss some possible pathogenetic mechanisms in the light of recent advances about the nAChR role in prefrontal regions as well as the studies carried out in murine models of ADNFLE. Functional evidence points to alterations in prefrontal GABA release, and the synaptic unbalance probably arises during the cortical circuit maturation. Although most of the available functional evidence concerns mutations on nAChR subunit genes, other genes have been recently implicated in the disease, such as KCNT1 (coding for a Na+-dependent K+ channel), DEPD5 (Disheveled, Egl-10 and Pleckstrin Domain-containing protein 5), and CRH (Corticotropin-Releasing Hormone). Overall, the uncertainties about both the etiology and the pathogenesis of ADNFLE point to the current gaps in our knowledge the regulation of neuronal networks in the cerebral cortex.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Patrizia Aracri
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Simone Meneghini
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Simone Brusco
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Alida Amadeo
- Department of Biosciences, University of Milano Milano, Italy
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20
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Braida D, Guerini FR, Ponzoni L, Corradini I, De Astis S, Pattini L, Bolognesi E, Benfante R, Fornasari D, Chiappedi M, Ghezzo A, Clerici M, Matteoli M, Sala M. Association between SNAP-25 gene polymorphisms and cognition in autism: functional consequences and potential therapeutic strategies. Transl Psychiatry 2015; 5:e500. [PMID: 25629685 PMCID: PMC4312830 DOI: 10.1038/tp.2014.136] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 11/19/2014] [Indexed: 12/27/2022] Open
Abstract
Synaptosomal-associated protein of 25 kDa (SNAP-25) is involved in different neuropsychiatric disorders, including schizophrenia and attention-deficit/hyperactivity disorder. Consistently, SNAP-25 polymorphisms in humans are associated with hyperactivity and/or with low cognitive scores. We analysed five SNAP-25 gene polymorphisms (rs363050, rs363039, rs363043, rs3746544 and rs1051312) in 46 autistic children trying to correlate them with Childhood Autism Rating Scale and electroencephalogram (EEG) abnormalities. The functional effects of rs363050 single-nucleotide polymorphism (SNP) on the gene transcriptional activity, by means of the luciferase reporter gene, were evaluated. To investigate the functional consequences that SNAP-25 reduction may have in children, the behaviour and EEG of SNAP-25(+/-) adolescent mice (SNAP-25(+/+)) were studied. Significant association of SNAP-25 polymorphism with decreasing cognitive scores was observed. Analysis of transcriptional activity revealed that SNP rs363050 encompasses a regulatory element, leading to protein expression decrease. Reduction of SNAP-25 levels in adolescent mice was associated with hyperactivity, cognitive and social impairment and an abnormal EEG, characterized by the occurrence of frequent spikes. Both EEG abnormalities and behavioural deficits were rescued by repeated exposure for 21 days to sodium salt valproate (VLP). A partial recovery of SNAP-25 expression content in SNAP-25(+/-) hippocampi was also observed by means of western blotting. A reduced expression of SNAP-25 is responsible for the cognitive deficits in children affected by autism spectrum disorders, as presumably occurring in the presence of rs363050(G) allele, and for behavioural and EEG alterations in adolescent mice. VLP treatment could result in novel therapeutic strategies.
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Affiliation(s)
- D Braida
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,Fondazione IRCCS Don Gnocchi, Milan, Italy
| | | | - L Ponzoni
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,Fondazione Fratelli Confalonieri, Milan, Italy
| | | | - S De Astis
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy
| | - L Pattini
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | | | - R Benfante
- CNR—Neuroscience Institute, Milan, Italy
| | - D Fornasari
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,CNR—Neuroscience Institute, Milan, Italy
| | - M Chiappedi
- Child Neuropsychiatry Unit, National Neurological Institute C. Mondino, Pavia, Italy
| | - A Ghezzo
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy,Associazione Nazionale Famiglie di Persone con Disabilitá Affettiva e/o Relazionale (ANFFAS), Macerata, Italy
| | - M Clerici
- Fondazione IRCCS Don Gnocchi, Milan, Italy,Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - M Matteoli
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,Humanitas Clinical and Research Center, Rozzano, Italy
| | - M Sala
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milan, Italy,CNR—Neuroscience Institute, Milan, Italy,Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Via Vanvitelli 32, Milan 20129, Italy. E-mail:
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21
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Subaran RL, Greenberg DA. The Genetics of Common Epilepsy Disorders: Lessons Learned from the Channelopathy Era. CURRENT GENETIC MEDICINE REPORTS 2014. [DOI: 10.1007/s40142-014-0040-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Gullo F, Manfredi I, Lecchi M, Casari G, Wanke E, Becchetti A. Multi-electrode array study of neuronal cultures expressing nicotinic β2-V287L subunits, linked to autosomal dominant nocturnal frontal lobe epilepsy. An in vitro model of spontaneous epilepsy. Front Neural Circuits 2014; 8:87. [PMID: 25104926 PMCID: PMC4109561 DOI: 10.3389/fncir.2014.00087] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/04/2014] [Indexed: 11/13/2022] Open
Abstract
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a partial sleep-related epilepsy which can be caused by mutant neuronal nicotinic acetylcholine receptors (nAChR). We applied multi-electrode array (MEA) recording methods to study the spontaneous firing activity of neocortical cultures obtained from mice expressing or not (WT) an ADNFLE-linked nAChR subunit (β2-V287L). More than 100,000 up-states were recorded during experiments sampling from several thousand neurons. Data were analyzed by using a fast sliding-window procedure which computes histograms of the up-state durations. Differently from the WT, cultures expressing β2-V287L displayed long (10–32 s) synaptic-induced up-state firing events. The occurrence of such long up-states was prevented by both negative (gabazine, penicillin G) and positive (benzodiazepines) modulators of GABAA receptors. Carbamazepine (CBZ), a drug of choice in ADNFLE patients, also inhibited the long up-states at micromolar concentrations. In cultures expressing β2-V287L, no significant effect was observed on the action potential waveform either in the absence or in the presence of pharmacological treatment. Our results show that some aspects of the spontaneous hyperexcitability displayed by a murine model of a human channelopathy can be reproduced in neuronal cultures. In particular, our cultures represent an in vitro chronic model of spontaneous epileptiform activity, i.e., not requiring pre-treatment with convulsants. This opens the way to the study in vitro of the role of β2-V287L on synaptic formation. Moreover, our neocortical cultures on MEA platforms allow to determine the effects of prolonged pharmacological treatment on spontaneous network hyperexcitability (which is impossible in the short-living brain slices). Methods such as the one we illustrate in the present paper should also considerably facilitate the preliminary screening of antiepileptic drugs (AEDs), thereby reducing the number of in vivo experiments.
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Affiliation(s)
- Francesca Gullo
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
| | - Irene Manfredi
- Center for Translational Genomics and Bioinformatics, Vita-Salute San Raffaele University and San Raffaele Scientific Institute Milano, Italy
| | - Marzia Lecchi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
| | - Giorgio Casari
- Center for Translational Genomics and Bioinformatics, Vita-Salute San Raffaele University and San Raffaele Scientific Institute Milano, Italy
| | - Enzo Wanke
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
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23
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Steinlein OK. Animal models for autosomal dominant frontal lobe epilepsy: on the origin of seizures. Expert Rev Neurother 2014; 10:1859-67. [DOI: 10.1586/ern.10.130] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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24
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Deng H, Xiu X, Song Z. The molecular biology of genetic-based epilepsies. Mol Neurobiol 2013; 49:352-67. [PMID: 23934645 DOI: 10.1007/s12035-013-8523-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 07/24/2013] [Indexed: 01/02/2023]
Abstract
Epilepsy is one of the most common neurological disorders characterized by abnormal electrical activity in the central nervous system. The clinical features of this disorder are recurrent seizures, difference in age onset, type, and frequency, leading to motor, sensory, cognitive, psychic, or autonomic disturbances. Since the discovery of the first monogenic gene mutation in 1995, it is proposed that genetic factor plays an important role in the mechanism of epilepsy. Genes discovered in idiopathic epilepsies encode for ion channel or neurotransmitter receptor proteins, whereas syndromes with epilepsy as a main feature are caused by genes that are involved in functions such as cortical development, mitochondrial function, and cell metabolism. The identification of these monogenic epilepsy-causing genes provides new insight into the pathogenesis of epilepsies. Although most of the identified gene mutations present a monogenic inheritance, most of idiopathic epilepsies are complex genetic diseases exhibiting a polygenic or oligogenic inheritance. This article reviews recent genetic and molecular progresses in exploring the pathogenesis of epilepsy, with special emphasis on monogenic epilepsy-causing genes, including voltage-gated channels (Na(+), K(+), Ca(2+), Cl(-), and HCN), ligand-gated channels (nicotinic acetylcholine and GABAA receptors), non-ion channel genes as well as the mitochondrial DNA genes. These progresses have improved our understanding of the complex neurological disorder.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Tongzipo Road 138, Changsha, Hunan, 410013, People's Republic of China,
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25
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Eps8 controls dendritic spine density and synaptic plasticity through its actin-capping activity. EMBO J 2013; 32:1730-44. [PMID: 23685357 DOI: 10.1038/emboj.2013.107] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/15/2013] [Indexed: 12/13/2022] Open
Abstract
Actin-based remodelling underlies spine structural changes occurring during synaptic plasticity, the process that constantly reshapes the circuitry of the adult brain in response to external stimuli, leading to learning and memory formation. A positive correlation exists between spine shape and synaptic strength and, consistently, abnormalities in spine number and morphology have been described in a number of neurological disorders. In the present study, we demonstrate that the actin-regulating protein, Eps8, is recruited to the spine head during chemically induced long-term potentiation in culture and that inhibition of its actin-capping activity impairs spine enlargement and plasticity. Accordingly, mice lacking Eps8 display immature spines, which are unable to undergo potentiation, and are impaired in cognitive functions. Additionally, we found that reduction in the levels of Eps8 occurs in brains of patients affected by autism compared to controls. Our data reveal the key role of Eps8 actin-capping activity in spine morphogenesis and plasticity and indicate that reductions in actin-capping proteins may characterize forms of intellectual disabilities associated with spine defects.
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Abstract
BACKGROUND Nocturnal frontal lobe epilepsy (NFLE) is an idiopathic partial epilepsy characterized by a wide spectrum of stereotyped motor manifestations, mostly occurring during non rapid eye movements sleep. NFLE is underdiagnosed since semiological similarities make it difficult to distinguish NFLE from parasomnias. In 1994, authors reported families with NFLE inherited as an autosomal dominant trait and they introduced the term of autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). A family history of possible NFLE is found in about 25% of cases. The genetic bases of the disease have been detected in a minority of cases. Mutations causing a gain of function of the neuronal nicotinic acetylcholine receptors were reported in 3 different subunits. REVIEW SUMMARY This review discusses the clinical aspects of NFLE and the diagnostic procedures. Furthermore, the genetic aspects are outlined. The main differentiating features characterizing NFLE are: (a) several attacks per night at any time during the night; (b) brief duration of the attacks; (c) stereotyped motor pattern. Nocturnal video-polysomnography is crucial for the diagnosis. Neurological examination in NFLE/ADNFLE is normal. About 30% of NFLE cases are resistant to antiepileptic drugs. Concerning the genetics, putative susceptibility nucleotide variations affecting the promoter of the CRH gene and altering the corticotrophin-releasing hormone levels have been reported in some NFLE patients. CONCLUSIONS Distinguishing NFLE seizures from paroxysmal nonepileptic sleep disorders is often difficult and sometimes impossible on clinical grounds alone. Nocturnal video-polysomnography is mandatory. Further genetic studies could help the diagnosis and treatment in NFLE patients.
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Becchetti A. Neuronal nicotinic receptors in sleep-related epilepsy: studies in integrative biology. ISRN BIOCHEMISTRY 2012; 2012:262941. [PMID: 25969754 PMCID: PMC4392997 DOI: 10.5402/2012/262941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 10/21/2012] [Indexed: 11/23/2022]
Abstract
Although Mendelian diseases are rare, when considered one by one, overall they constitute a significant social burden. Besides the medical aspects, they propose us one of the most general biological problems. Given the simplest physiological perturbation of an organism, that is, a single gene mutation, how do its effects percolate through the hierarchical biological levels to determine the pathogenesis? And how robust is the physiological system to this perturbation? To solve these problems, the study of genetic epilepsies caused by mutant ion channels presents special advantages, as it can exploit the full range of modern experimental methods. These allow to extend the functional analysis from single channels to whole brains. An instructive example is autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), which can be caused by mutations in neuronal nicotinic acetylcholine receptors. In vitro, such mutations often produce hyperfunctional receptors, at least in heterozygous condition. However, understanding how this leads to sleep-related frontal epilepsy is all but straightforward. Several available animal models are helping us to determine the effects of ADNFLE mutations on the mammalian brain. Because of the complexity of the cholinergic regulation in both developing and mature brains, several pathogenic mechanisms are possible, which also present different therapeutic implications.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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Mice expressing the ADNFLE valine 287 leucine mutation of the Β2 nicotinic acetylcholine receptor subunit display increased sensitivity to acute nicotine administration and altered presynaptic nicotinic receptor function. Pharmacol Biochem Behav 2012; 103:603-21. [PMID: 23123803 DOI: 10.1016/j.pbb.2012.10.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/26/2012] [Accepted: 10/24/2012] [Indexed: 01/16/2023]
Abstract
Several mutations in α4 or β2 nicotinic receptor subunits are linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). One such missense mutation in the gene encoding the β2 neuronal nicotinic acetylcholine receptor (nAChR) subunit (CHRNB2) is a valine-to-leucine substitution in the second transmembrane domain at position 287 (β2VL). Previous studies indicated that the β2VL mutation in mice alters circadian rhythm consistent with sleep alterations observed in ADNFLE patients (Xu et al., 2011). The current study investigates changes in nicotinic receptor function and expression that may explain the behavioral phenotype of β2VL mice. No differences in β2 mRNA expression were found between wild-type (WT) and heterozygous (HT) or homozygous mutant (MT) mice. However, antibody and ligand binding indicated that the mutation resulted in a reduction in receptor protein. Functional consequences of the β2VL mutation were assessed biochemically using crude synaptosomes. A gene-dose dependent increase in sensitivity to activation by acetylcholine and decrease in maximal nAChR-mediated [(3)H]-dopamine release and (86)Rb efflux were observed. Maximal nAChR-mediated [(3)H]-GABA release in the cortex was also decreased in the MT, but maximal [(3)H]-GABA release was retained in the hippocampus. Behaviorally both HT and MT mice demonstrated increased sensitivity to nicotine-induced hypolocomotion and hypothermia. Furthermore, WT mice display only a tonic-clonic seizure (EEG recordable) 3 min after injection of a high dose of nicotine, while MT mice also display a dystonic arousal complex (non-EEG recordable) event 30s after nicotine injection. Data indicate decreases in maximal response for certain measures are larger than expected given the decrease in receptor expression.
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Corradini I, Donzelli A, Antonucci F, Welzl H, Loos M, Martucci R, De Astis S, Pattini L, Inverardi F, Wolfer D, Caleo M, Bozzi Y, Verderio C, Frassoni C, Braida D, Clerici M, Lipp HP, Sala M, Matteoli M. Epileptiform Activity and Cognitive Deficits in SNAP-25+/− Mice are Normalized by Antiepileptic Drugs. Cereb Cortex 2012; 24:364-76. [DOI: 10.1093/cercor/bhs316] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Xu J, Cohen BN, Zhu Y, Dziewczapolski G, Panda S, Lester HA, Heinemann SF, Contractor A. Altered activity-rest patterns in mice with a human autosomal-dominant nocturnal frontal lobe epilepsy mutation in the β2 nicotinic receptor. Mol Psychiatry 2011; 16:1048-61. [PMID: 20603624 PMCID: PMC2970689 DOI: 10.1038/mp.2010.78] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High-affinity nicotinic receptors containing β2 subunits (β2*) are widely expressed in the brain, modulating many neuronal processes and contributing to neuropathologies such as Alzheimer's disease, Parkinson's disease and epilepsy. Mutations in both the α4 and β2 subunits are associated with a rare partial epilepsy, autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). In this study, we introduced one such human missense mutation into the mouse genome to generate a knock-in strain carrying a valine-to-leucine mutation β2V287L. β2(V287L) mice were viable and born at an expected Mendelian ratio. Surprisingly, mice did not show an overt seizure phenotype; however, homozygous mice did show significant alterations in their activity-rest patterns. This was manifest as an increase in activity during the light cycle suggestive of disturbances in the normal sleep patterns of mice; a parallel phenotype to that found in human ADNFLE patients. Consistent with the role of nicotinic receptors in reward pathways, we found that β2(V287L) mice did not develop a normal proclivity to voluntary wheel running, a model for natural reward. Anxiety-related behaviors were also affected by the V287L mutation. Mutant mice spent more time in the open arms on the elevated plus maze suggesting that they had reduced levels of anxiety. Together, these findings emphasize several important roles of β2* nicotinic receptors in complex biological processes including the activity-rest cycle, natural reward and anxiety.
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Affiliation(s)
- Jian Xu
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, The Salk Institute for Biological Studies, Molecular Neurobiology Lab, La Jolla CA 92037
| | - Bruce N. Cohen
- California Institute of Technology, Division of Biology, Pasadena CA 92215
| | - Yongling Zhu
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, The Salk Institute for Biological Studies, Molecular Neurobiology Lab, La Jolla CA 92037
| | - Gustavo Dziewczapolski
- The Salk Institute for Biological Studies, Molecular Neurobiology Lab, La Jolla CA 92037
| | - Satchidananda Panda
- The Salk Institute for Biological Studies, Molecular Neurobiology Lab, La Jolla CA 92037
| | - Henry A. Lester
- California Institute of Technology, Division of Biology, Pasadena CA 92215
| | - Stephen F. Heinemann
- The Salk Institute for Biological Studies, Molecular Neurobiology Lab, La Jolla CA 92037
| | - Anis Contractor
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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Tammimäki A, Horton WJ, Stitzel JA. Recent advances in gene manipulation and nicotinic acetylcholine receptor biology. Biochem Pharmacol 2011; 82:808-19. [PMID: 21704022 DOI: 10.1016/j.bcp.2011.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/07/2011] [Accepted: 06/08/2011] [Indexed: 11/26/2022]
Abstract
Pharmacological and immunological methods have been valuable for both identifying some native nicotinic acetylcholine receptor (nAChR) subtypes that exist in vivo and determining the neurobiological and behavioral role of certain nAChR subtypes. However, these approaches suffer from shortage of subtype specific ligands and reliable immunological reagents. Consequently, genetic approaches have been developed to complement earlier approaches to identify native nAChR subtypes and to assess the contribution of nAChRs to brain function and behavior. In this review we describe how assembly partners, knock-in mice and targeted lentiviral re-expression of genes have been utilized to improve our understanding of nAChR neurobiology. In addition, we summarize emerging genetic tools in nAChR research.
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Affiliation(s)
- Anne Tammimäki
- Institute for Behavioral Genetics, University of Colorado at Boulder, UCB 447, Boulder, CO 80309, United States.
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Pharmacologic rescue of impaired cognitive flexibility, social deficits, increased aggression, and seizure susceptibility in oxytocin receptor null mice: a neurobehavioral model of autism. Biol Psychiatry 2011; 69:875-82. [PMID: 21306704 DOI: 10.1016/j.biopsych.2010.12.022] [Citation(s) in RCA: 263] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 01/29/2023]
Abstract
BACKGROUND Oxytocin (OT) has been suggested as a treatment to improve social behavior in autistic patients. Accordingly, the OT (Oxt(-/-)) and the OT receptor null mice (Oxtr(-/-)) display autistic-like deficits in social behavior, increased aggression, and reduced ultrasonic vocalization. METHODS Oxtr(-/-) mice were characterized for general health, sociability, social novelty, cognitive flexibility, aggression, and seizure susceptibility. Because vasopressin (AVP) and OT cooperate in controlling social behavior, learning, and aggression, they were tested for possible rescue of the impaired behaviors. Primary hyppocampal cultures from Oxtr(+/+) and Oxtr(-/-) mouse embryos were established to investigate the balance between gamma-aminobutyric acid (GABA) and glutamate synapses and the expression levels of OT and AVP (V1a) receptors were determined by autoradiography. RESULTS Oxtr(-/-) mice display two additional, highly relevant, phenotypic characteristics: 1) a resistance to change in a learned pattern of behavior, comparable to restricted interests and repetitive behavior in autism, and 2) an increased susceptibility to seizures, a frequent and clinically relevant symptom of autism. We also show that intracerebral administration of both OT and AVP lowers aggression and fully reverts social and learning defects by acting on V1a receptors and that seizure susceptibility is antagonized by peripherally administered OT. Finally, we detect a decreased ratio of GABA-ergic versus total presynapses in hippocampal neurons of Oxtr(-/-) mice. CONCLUSIONS Autistic-like symptoms are rescued on administration of AVP and OT to young Oxtr(-/-) adult animals. The Oxtr(-/-) mouse is thus instrumental to investigate the neurochemical and synaptic abnormalities underlying autistic-like disturbances and to test new strategies of pharmacologic intervention.
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Bialer M, White HS. Key factors in the discovery and development of new antiepileptic drugs. Nat Rev Drug Discov 2010; 9:68-82. [PMID: 20043029 DOI: 10.1038/nrd2997] [Citation(s) in RCA: 374] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Since the early 1990s, many new antiepileptic drugs (AEDs) that offer appreciable advantages in terms of their favourable pharmacokinetics, improved tolerability and lower potential for drug-drug interactions have entered the market. However, despite the therapeutic arsenal of old and new AEDs, approximately 30% of patients with epilepsy still suffer from seizures. Thus, there remains a substantial need for the development of more efficacious AEDs for patients with refractory seizures. Here, we briefly review the emerging knowledge on the pathological basis of epilepsy and how it might best be used in the design of new therapeutics. We also discuss the current approach to AED discovery and highlight some of the unique features of newer models of pharmacoresistance and epileptogenesis that have emerged in recent years.
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Affiliation(s)
- Meir Bialer
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, and the David R. Bloom Centre for Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Genetic basis in epilepsies caused by malformations of cortical development and in those with structurally normal brain. Hum Genet 2009; 126:173-93. [PMID: 19536565 DOI: 10.1007/s00439-009-0702-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 06/02/2009] [Indexed: 01/10/2023]
Abstract
Epilepsy is the most common neurological disorder affecting young people. The etiologies are multiple and most cases are sporadic. However, some rare families with Mendelian inheritance have provided evidence of genes' important role in epilepsy. Two important but apparently different groups of disorders have been extensively studied: epilepsies associated with malformations of cortical development (MCDs) and epilepsies associated with a structurally normal brain (or with minimal abnormalities only). This review is focused on clinical and molecular aspects of focal cortical dysplasia, polymicrogyria, periventricular nodular heterotopia, subcortical band heterotopia, lissencephaly and schizencephaly as examples of MCDs. Juvenile myoclonic epilepsy, childhood absence epilepsy, some familial forms of focal epilepsy and epilepsies associated with febrile seizures are discussed as examples of epileptic conditions in (apparently) structurally normal brains.
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