1
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Certain N, Gan Q, Bennett J, Hsieh H, Wollmuth LP. Differential regulation of tetramerization of the AMPA receptor glutamate-gated ion channel by auxiliary subunits. J Biol Chem 2023; 299:105227. [PMID: 37673338 PMCID: PMC10558804 DOI: 10.1016/j.jbc.2023.105227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/21/2023] [Accepted: 08/24/2023] [Indexed: 09/08/2023] Open
Abstract
α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) auxiliary subunits are specialized, nontransient binding partners of AMPARs that modulate AMPAR channel gating properties and pharmacology, as well as their biogenesis and trafficking. The most well-characterized families of auxiliary subunits are transmembrane AMPAR regulatory proteins (TARPs), cornichon homologs (CNIHs), and the more recently discovered GSG1-L. These auxiliary subunits can promote or reduce surface expression of AMPARs (composed of GluA1-4 subunits) in neurons, thereby impacting their functional role in membrane signaling. Here, we show that CNIH-2 enhances the tetramerization of WT and mutant AMPARs, presumably by increasing the overall stability of the tetrameric complex, an effect that is mainly mediated by interactions with the transmembrane domain of the receptor. We also find CNIH-2 and CNIH-3 show receptor subunit-specific actions in this regard with CNIH-2 enhancing both GluA1 and GluA2 tetramerization, whereas CNIH-3 only weakly enhances GluA1 tetramerization. These results are consistent with the proposed role of CNIHs as endoplasmic reticulum cargo transporters for AMPARs. In contrast, TARP γ-2, TARP γ-8, and GSG1-L have no or negligible effect on AMPAR tetramerization. On the other hand, TARP γ-2 can enhance receptor tetramerization but only when directly fused with the receptor at a maximal stoichiometry. Notably, surface expression of functional AMPARs was enhanced by CNIH-2 to a greater extent than TARP γ-2, suggesting that this distinction aids in maturation and membrane expression. These experiments define a functional distinction between CNIHs and other auxiliary subunits in the regulation of AMPAR biogenesis.
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Affiliation(s)
- Noele Certain
- Graduate Program in Molecular and Cellular Pharmacology, Stony Brook University, Stony Brook, New York, USA
| | - Quan Gan
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, New York, USA
| | - Joseph Bennett
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, New York, USA
| | - Helen Hsieh
- Department of Surgery, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA; Center for Nervous System Disorders, Stony Brook University, Stony Brook, New York, USA
| | - Lonnie P Wollmuth
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, New York, USA; Center for Nervous System Disorders, Stony Brook University, Stony Brook, New York, USA; Department of Biochemistry & Cell Biology, Stony Brook University, Stony Brook, New York, USA.
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2
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Certain N, Gan Q, Bennett J, Hsieh H, Wollmuth LP. Differential regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) receptor tetramerization by auxiliary subunits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527516. [PMID: 36798164 PMCID: PMC9934675 DOI: 10.1101/2023.02.07.527516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
AMPA receptor (AMPAR) auxiliary subunits are specialized, non-transient binding partners of AMPARs that modulate their ion channel gating properties and pharmacology, as well as their biogenesis and trafficking. The most well characterized families of auxiliary subunits are transmembrane AMPAR regulatory proteins (TARPs) and cornichon homologs (CNIHs) and the more recently discovered GSG1-L. These auxiliary subunits can promote or reduce surface expression of AMPARs in neurons, thereby impacting their functional role in membrane signaling. Here, we show that CNIH-2 enhances the tetramerization of wild type and mutant AMPARs, possibly by increasing the overall stability of the tetrameric complex, an effect that is mainly mediated by interactions with the transmembrane domain of the receptor. We also find CNIH-2 and CNIH-3 show receptor subunit-specific actions in this regard with CNIH-2 enhancing both GluA1 and GluA2 tetramerization whereas CNIH-3 only weakly enhances GluA1 tetramerization. These results are consistent with the proposed role of CNIHs as endoplasmic reticulum cargo transporters for AMPARs. In contrast, TARP γ-2, TARP γ-8, and GSG1-L have no or negligible effect on AMPAR tetramerization. On the other hand, TARP γ-2 can enhance receptor tetramerization but only when directly fused with the receptor at a maximal stoichiometry. Notably, surface expression of functional AMPARs was enhanced by CNIH-2 to a greater extent than TARP γ-2 suggesting that this distinction aids in maturation and membrane expression. These experiments define a functional distinction between CNIHs and other auxiliary subunits in the regulation of AMPAR biogenesis.
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3
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Benesh JL, Mueller TM, Meador-Woodruff JH. AMPA receptor subunit localization in schizophrenia anterior cingulate cortex. Schizophr Res 2022; 249:16-24. [PMID: 32014361 DOI: 10.1016/j.schres.2020.01.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/21/2020] [Accepted: 01/23/2020] [Indexed: 12/14/2022]
Abstract
The glutamate hypothesis of schizophrenia suggests that altered glutamatergic transmission occurs in this illness, although precise mechanisms of dysregulation remain elusive. AMPA receptors (AMPARs), a subtype of ionotropic glutamate receptor, are the main facilitators of fast, excitatory neurotransmission in the brain, and changes in AMPAR number or composition at synapses can regulate synaptic strength and plasticity. Prior evidence of abnormal expression of transmembrane AMPAR regulatory proteins (TARPs) in schizophrenia suggests defective trafficking of AMPARs, which we propose could lead to altered AMPAR expression at excitatory synapses. To test this hypothesis, we isolated subcellular fractions enriched for endoplasmic reticulum (ER) and synapses from anterior cingulate cortex (ACC) from schizophrenia (N = 18) and comparison (N = 18) subjects, and measured glutamate receptor subunits (GluA1, GluA2, GluA3, GluA4, NR1, NR2A, NR2B, and NR3A) and TARP member γ2 (stargazin) in homogenates and subcellular fractions by western blot analysis. We found decreased expression of stargazin and an increased ratio of GluA2:stargazin in ACC homogenates, while in the synapse fraction we identified a decrease in GluA1 and reduced ratios of GluA1:stargazin and GluA1:GluA2 in schizophrenia. The amount of stargazin in the ER fraction was not different, but the relative amount of ER/Total stargazin was increased in schizophrenia. Together, these findings suggest that associations between stargazin and AMPA subunits are abnormal, potentially affecting forward trafficking or synaptic stability of GluA1-containing AMPARs. These data provide evidence that altered interactions with trafficking proteins may contribute to glutamate dysregulation in schizophrenia.
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Affiliation(s)
- Jana L Benesh
- University of Alabama at Birmingham, Department of Psychiatry and Behavioral Neurobiology, 1720 2nd Ave S., Birmingham, AL 35294, United States of America
| | - Toni M Mueller
- University of Alabama at Birmingham, Department of Psychiatry and Behavioral Neurobiology, 1720 2nd Ave S., Birmingham, AL 35294, United States of America.
| | - James H Meador-Woodruff
- University of Alabama at Birmingham, Department of Psychiatry and Behavioral Neurobiology, 1720 2nd Ave S., Birmingham, AL 35294, United States of America
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4
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Felix R, Muñoz-Herrera D, Corzo-López A, Fernández-Gallardo M, Leyva-Leyva M, González-Ramírez R, Sandoval A. Ion channel long non-coding RNAs in neuropathic pain. Pflugers Arch 2022; 474:457-468. [PMID: 35235008 DOI: 10.1007/s00424-022-02675-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023]
Abstract
Neuropathic pain is one of the primary forms of chronic pain and is the consequence of the somatosensory system's direct injury or disease. It is a relevant public health problem that affects about 10% of the world's general population. In neuropathic pain, alteration in neurotransmission occurs at various levels, including the dorsal root ganglia, the spinal cord, and the brain, resulting from the malfunction of diverse molecules such as receptors, ion channels, and elements of specific intracellular signaling pathways. In this context, there have been exciting advances in elucidating neuropathic pain's cellular and molecular mechanisms in the last decade, including the possible role that long non-coding RNAs (lncRNAs) may play, which open up new alternatives for the development of diagnostic and therapeutic strategies for this condition. This review focuses on recent studies associated with the possible relevance of lncRNAs in the development and maintenance of neuropathic pain through their actions on the functional expression of ion channels. Recognizing the changes in the function and spatio-temporal patterns of expression of these membrane proteins is crucial to understanding the control of neuronal excitability in chronic pain syndromes.
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Affiliation(s)
- Ricardo Felix
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico.
| | - David Muñoz-Herrera
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico
| | - Alejandra Corzo-López
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico
| | | | - Margarita Leyva-Leyva
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Alejandro Sandoval
- School of Medicine FES Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico
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5
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Lou S, Cui S. Drug treatment of epilepsy: From serendipitous discovery to evolutionary mechanisms. Curr Med Chem 2021; 29:3366-3391. [PMID: 34514980 DOI: 10.2174/0929867328666210910124727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/17/2021] [Accepted: 07/21/2021] [Indexed: 11/22/2022]
Abstract
Epilepsy is a chronic brain disorder caused by abnormal firing of neurons. Up to now, using antiepileptic drugs is the main method of epilepsy treatment. The development of antiepileptic drugs lasted for centuries. In general, most agents entering clinical practice act on the balance mechanisms of brain "excitability-inhibition". More specifically, they target voltage-gated ion channels, GABAergic transmission and glutamatergic transmission. In recent years, some novel drugs representing new mechanisms of action have been discovered. Although there are about 30 available drugs in the market, it is still in urgent need of discovering more effective and safer drugs. The development of new antiepileptic drugs is into a new era: from serendipitous discovery to evolutionary mechanism-based design. This article presents an overview of drug treatment of epilepsy, including a series of traditional and novel drugs.
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Affiliation(s)
- Shengying Lou
- Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou. China
| | - Sunliang Cui
- Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou. China
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6
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Parkinson GT, Hanley JG. Mechanisms of AMPA Receptor Endosomal Sorting. Front Mol Neurosci 2018; 11:440. [PMID: 30568574 PMCID: PMC6289981 DOI: 10.3389/fnmol.2018.00440] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022] Open
Abstract
The regulation of synaptic AMPA receptors (AMPARs) is critical for excitatory synaptic transmission, synaptic plasticity and the consequent formation of neural circuits during brain development and their modification during learning and memory processes. The number of synaptic AMPARs is regulated through endocytosis, exocytosis and endosomal sorting that results in recycling back to the plasma membrane or degradation in the lysosome. Hence, endo-lysosomal sorting is vitally important in maintaining AMPAR expression at the synapse, and the dynamic regulation of these trafficking events is a key component of synaptic plasticity. A reduction in synaptic strength such as in long-term depression (LTD) involves AMPAR sorting to lysosomes to reduce synaptic AMPAR number, whereas long-term potentiation (LTP) involves an increase in AMPAR recycling to increase the number of AMPARs at synapses. Here, we review our current understanding of the endosomal trafficking routes taken by AMPARs, and the mechanisms involved in AMPAR endosomal sorting, focussing on the numerous AMPAR associated proteins that have been implicated in this complex process. We also discuss how these events are dysregulated in brain disorders.
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Affiliation(s)
- Gabrielle T Parkinson
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Jonathan G Hanley
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
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7
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Crespi A, Plutino S, Sciaccaluga M, Righi M, Borgese N, Fucile S, Gotti C, Colombo SF. The fifth subunit in α3β4 nicotinic receptor is more than an accessory subunit. FASEB J 2018; 32:4190-4202. [PMID: 29505300 DOI: 10.1096/fj.201701377r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The α3β4 subtype is the predominant neuronal nicotinic acetylcholine receptor present in the sensory and autonomic ganglia and in a subpopulation of brain neurons. This subtype can form pentameric receptors with either 2 or 3 β4 subunits that have different pharmacologic and functional properties. To further investigate the role of the fifth subunit, we coexpressed a dimeric construct coding for a single polypeptide containing the β4 and α3 subunit sequences, with different monomeric subunits. With this strategy, which allowed the formation of single populations of receptors with unique stoichiometry, we demonstrated with immunofluorescence and biochemical and functional assays that only the receptors with 3 β4 subunits are efficiently expressed at the plasma membrane. Moreover, the LFM export motif of β4 subunit in the fifth position exerts a unique function in the regulation of the intracellular trafficking of the receptors, their exposure at the cell surface, and consequently, their function, whereas the same export motif present in the β4 subunits forming the acetylcholine binding site is dispensable.-Crespi, A., Plutino, S., Sciaccaluga, M., Righi, M., Borgese, N., Fucile, S., Gotti, C., Colombo, S. F. The fifth subunit in α3β4 nicotinic receptor is more than an accessory subunit.
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Affiliation(s)
- Arianna Crespi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.,Consiglio Nazionale delle Ricerche (CNR) Institute of Neuroscience, Milan, Italy
| | - Simona Plutino
- Dipartimento di Fisiologia e Farmacologia, Università di Roma La Sapienza, Rome, Italy; and
| | - Miriam Sciaccaluga
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, Istituto Neurologico Mediterraneo, Pozzilli, Italy
| | - Marco Righi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.,Consiglio Nazionale delle Ricerche (CNR) Institute of Neuroscience, Milan, Italy
| | - Nica Borgese
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.,Consiglio Nazionale delle Ricerche (CNR) Institute of Neuroscience, Milan, Italy
| | - Sergio Fucile
- Dipartimento di Fisiologia e Farmacologia, Università di Roma La Sapienza, Rome, Italy; and.,Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, Istituto Neurologico Mediterraneo, Pozzilli, Italy
| | - Cecilia Gotti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.,Consiglio Nazionale delle Ricerche (CNR) Institute of Neuroscience, Milan, Italy
| | - Sara Francesca Colombo
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.,Consiglio Nazionale delle Ricerche (CNR) Institute of Neuroscience, Milan, Italy
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8
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Schmitz LJM, Klaassen RV, Ruiperez-Alonso M, Zamri AE, Stroeder J, Rao-Ruiz P, Lodder JC, van der Loo RJ, Mansvelder HD, Smit AB, Spijker S. The AMPA receptor-associated protein Shisa7 regulates hippocampal synaptic function and contextual memory. eLife 2017; 6:24192. [PMID: 29199957 PMCID: PMC5737659 DOI: 10.7554/elife.24192] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 12/02/2017] [Indexed: 12/20/2022] Open
Abstract
Glutamatergic synapses rely on AMPA receptors (AMPARs) for fast synaptic transmission and plasticity. AMPAR auxiliary proteins regulate receptor trafficking, and modulate receptor mobility and its biophysical properties. The AMPAR auxiliary protein Shisa7 (CKAMP59) has been shown to interact with AMPARs in artificial expression systems, but it is unknown whether Shisa7 has a functional role in glutamatergic synapses. We show that Shisa7 physically interacts with synaptic AMPARs in mouse hippocampus. Shisa7 gene deletion resulted in faster AMPAR currents in CA1 synapses, without affecting its synaptic expression. Shisa7 KO mice showed reduced initiation and maintenance of long-term potentiation of glutamatergic synapses. In line with this, Shisa7 KO mice showed a specific deficit in contextual fear memory, both short-term and long-term after conditioning, whereas auditory fear memory and anxiety-related behavior were normal. Thus, Shisa7 is a bona-fide AMPAR modulatory protein affecting channel kinetics of AMPARs, necessary for synaptic hippocampal plasticity, and memory recall.
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Affiliation(s)
- Leanne J M Schmitz
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands.,Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - Remco V Klaassen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Marta Ruiperez-Alonso
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Azra Elia Zamri
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands.,Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Jasper Stroeder
- Sylics (Synaptologics BV), Amsterdam, The Netherlands.,Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Priyanka Rao-Ruiz
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Johannes C Lodder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Rolinka J van der Loo
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands.,Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - Huib D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Sabine Spijker
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
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Kato AS, Witkin JM. Auxiliary subunits of AMPA receptors: The discovery of a forebrain-selective antagonist, LY3130481/CERC-611. Biochem Pharmacol 2017; 147:191-200. [PMID: 28987594 DOI: 10.1016/j.bcp.2017.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022]
Abstract
Drugs originate from the discovery of compounds, natural or synthetic, that bind to proteins (receptors, enzymes, transporters, etc.), the interaction of which modulates biological cascades that have potential therapeutic benefit. Rational strategies for identifying novel drug therapies are typically based on knowledge of the structure of the target proteins and the design of new chemical entities that modulate these proteins in a beneficial manner. The present review discusses a novel approach to drug discovery based on the identification and characterization of auxiliary proteins, the transmembrane AMPA receptor regulatory proteins (TARPs) that are associated with AMPA receptors. Utilizing these auxiliary proteins in compound screening led to the discovery of the TARP-dependent-AMPA forebrain selective receptor antagonist (TDAA), LY3130481/CERC-611 that is currently in clinical development for epilepsy.
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Affiliation(s)
- Akihiko S Kato
- Neuroscience Discovery Research, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN 46285-0510, United States.
| | - Jeffrey M Witkin
- Neuroscience Discovery Research, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN 46285-0510, United States.
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10
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Kunde SA, Rademacher N, Zieger H, Shoichet SA. Protein kinase C regulates AMPA receptor auxiliary protein Shisa9/CKAMP44 through interactions with neuronal scaffold PICK1. FEBS Open Bio 2017; 7:1234-1245. [PMID: 28904854 PMCID: PMC5586339 DOI: 10.1002/2211-5463.12261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/19/2017] [Accepted: 06/08/2017] [Indexed: 12/22/2022] Open
Abstract
Synaptic α‐amino‐3‐hydroxyl‐5‐methyl‐4‐isoxazole‐propionate (AMPA) receptors are essential mediators of neurotransmission in the central nervous system. Shisa9/cysteine‐knot AMPAR modulating protein 44 (CKAMP44) is a transmembrane protein recently found to be present in AMPA receptor‐associated protein complexes. Here, we show that the cytosolic tail of Shisa9/CKAMP44 interacts with multiple scaffold proteins that are important for regulating synaptic plasticity in central neurons. We focussed on the interaction with the scaffold protein PICK1, which facilitates the formation of a tripartite complex with the protein kinase C (PKC) and thereby regulates phosphorylation of Shisa9/CKAMP44 C‐terminal residues. This work has implications for our understanding of how PICK1 modulates AMPAR‐mediated transmission and plasticity and also highlights a novel function of PKC.
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Affiliation(s)
- Stella-Amrei Kunde
- Neuroscience Research Center/Institute of Biochemistry Charité - Universitätsmedizin Berlin Germany
| | - Nils Rademacher
- Neuroscience Research Center/Institute of Biochemistry Charité - Universitätsmedizin Berlin Germany
| | - Hanna Zieger
- Neuroscience Research Center/Institute of Biochemistry Charité - Universitätsmedizin Berlin Germany
| | - Sarah A Shoichet
- Neuroscience Research Center/Institute of Biochemistry Charité - Universitätsmedizin Berlin Germany
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11
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Abstract
AMPA receptors (AMPARs) are assemblies of four core subunits, GluA1-4, that mediate most fast excitatory neurotransmission. The component subunits determine the functional properties of AMPARs, and the prevailing view is that the subunit composition also determines AMPAR trafficking, which is dynamically regulated during development, synaptic plasticity and in response to neuronal stress in disease. Recently, the subunit dependence of AMPAR trafficking has been questioned, leading to a reappraisal of this field. In this Review, we discuss what is known, uncertain, conjectured and unknown about the roles of the individual subunits, and how they affect AMPAR assembly, trafficking and function under both normal and pathological conditions.
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12
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Yang HC, Chu SK, Huang CL, Kuo HW, Wang SC, Liu SW, Ho IK, Liu YL. Genome-Wide Pharmacogenomic Study on Methadone Maintenance Treatment Identifies SNP rs17180299 and Multiple Haplotypes on CYP2B6, SPON1, and GSG1L Associated with Plasma Concentrations of Methadone R- and S-enantiomers in Heroin-Dependent Patients. PLoS Genet 2016; 12:e1005910. [PMID: 27010727 PMCID: PMC4806848 DOI: 10.1371/journal.pgen.1005910] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 02/09/2016] [Indexed: 01/25/2023] Open
Abstract
Methadone maintenance treatment (MMT) is commonly used for controlling opioid dependence, preventing withdrawal symptoms, and improving the quality of life of heroin-dependent patients. A steady-state plasma concentration of methadone enantiomers, a measure of methadone metabolism, is an index of treatment response and efficacy of MMT. Although the methadone metabolism pathway has been partially revealed, no genome-wide pharmacogenomic study has been performed to identify genetic determinants and characterize genetic mechanisms for the plasma concentrations of methadone R- and S-enantiomers. This study was the first genome-wide pharmacogenomic study to identify genes associated with the plasma concentrations of methadone R- and S-enantiomers and their respective metabolites in a methadone maintenance cohort. After data quality control was ensured, a dataset of 344 heroin-dependent patients in the Han Chinese population of Taiwan who underwent MMT was analyzed. Genome-wide single-locus and haplotype-based association tests were performed to analyze four quantitative traits: the plasma concentrations of methadone R- and S-enantiomers and their respective metabolites. A significant single nucleotide polymorphism (SNP), rs17180299 (raw p = 2.24 × 10−8), was identified, accounting for 9.541% of the variation in the plasma concentration of the methadone R-enantiomer. In addition, 17 haplotypes were identified on SPON1, GSG1L, and CYP450 genes associated with the plasma concentration of methadone S-enantiomer. These haplotypes accounted for approximately one-fourth of the variation of the overall S-methadone plasma concentration. The association between the S-methadone plasma concentration and CYP2B6, SPON1, and GSG1L were replicated in another independent study. A gene expression experiment revealed that CYP2B6, SPON1, and GSG1L can be activated concomitantly through a constitutive androstane receptor (CAR) activation pathway. In conclusion, this study revealed new genes associated with the plasma concentration of methadone, providing insight into the genetic foundation of methadone metabolism. The results can be applied to predict treatment responses and methadone-related deaths for individualized MMTs. Methadone maintenance treatment (MMT), among the most effective therapies for heroin-dependent patients, reduces craving and withdrawal symptoms, increases treatment compliance, and improves the quality of life of patients. The plasma concentration of methadone is a primary index for quantifying and determining therapy responses to MMT. This study was the first whole-genome pharmacogenomic study on MMT to locate genomic regions associated with the plasma concentration of methadone. The analysis identified a single nucleotide polymorphism (SNP) marker (rs17180299) and 17 haplotypes on the SPON1, GSG1L, and CYP450 genes, including CYP2B6 significantly associated with the plasma concentrations of methadone enantiomers. The identified genetic variations accounted for approximately 10% and 25% of the variations in plasma concentrations of methadone R- and S-enantiomers, respectively. The identified genetic variations have afforded insight into the genetic mechanism of the metabolism of MMT, and have potential to pave the way towards individualized MMTs for heroin-dependent patients.
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Affiliation(s)
- Hsin-Chou Yang
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
- Bioinformatics Program, Taiwan International Graduate Program, Institute of Information Science, Academia Sinica, Taipei, Taiwan
- Institute of Public Health, National Yang Ming University, Taipei, Taiwan
- Department of Statistics, National Cheng-Kung University, Tainan, Taiwan
- School of Public Health, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Kai Chu
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
- Bioinformatics Program, Taiwan International Graduate Program, Institute of Information Science, Academia Sinica, Taipei, Taiwan
- Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan
| | - Chieh-Liang Huang
- Center for Drug Abuse and Addiction, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, China Medical University, Taichung, Taiwan
| | - Hsiang-Wei Kuo
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Sheng-Chang Wang
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Sheng-Wen Liu
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Ing-Kang Ho
- Center for Drug Abuse and Addiction, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Li Liu
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
- Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
- * E-mail:
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Kovács AD, Hof C, Pearce DA. Abnormally increased surface expression of AMPA receptors in the cerebellum, cortex and striatum of Cln3(-/-) mice. Neurosci Lett 2015; 607:29-34. [PMID: 26375929 DOI: 10.1016/j.neulet.2015.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 09/02/2015] [Accepted: 09/09/2015] [Indexed: 11/16/2022]
Abstract
Mutations in the CLN3 gene cause a fatal neurodegenerative disorder, juvenile CLN3 disease. Exploring the cause of the motor coordination deficit in the Cln3(-/-) mouse model of the disease we have previously found that attenuation of AMPA receptor activity in 1-month-old Cln3(-/-) mice significantly improves their motor coordination [20]. To elucidate the mechanism of the abnormally increased AMPA receptor function in Cln3(-/-) mice, we examined the surface expression of AMPA receptors using surface cross-linking in brain slices from 1-month-old wild type (WT) and Cln3(-/-) mice. In surface cross-linked brain samples, Western blotting for AMPA receptor subunits revealed significantly increased surface levels of GluA1 and GluA2 in the cerebellum, and of GluA2 in the cortex and striatum of Cln3(-/-) mice as compared to WT mice. Expression levels of the GluA4 subunit were similar in the cerebellum of WT and Cln3(-/-) mice. While intracellular GluA1 levels in the WT and Cln3(-/-) cerebellum or cortex were similar, the intracellular expression of GluA1 in the Cln3(-/-) striatum was decreased to 56% of the WT level. Our results show a prominent increase in AMPA receptor surface expression in the brain of Cln3(-/-) mice and suggest that CLN3 is involved in the regulation of AMPA receptor surface expression.
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Affiliation(s)
- Attila D Kovács
- Sanford Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104, USA
| | - Caitlin Hof
- Sanford Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104, USA
| | - David A Pearce
- Sanford Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104, USA; Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57104, USA.
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Hamakawa M, Uozumi T, Ueda N, Iino Y, Hirotsu T. A role for Ras in inhibiting circular foraging behavior as revealed by a new method for time and cell-specific RNAi. BMC Biol 2015; 13:6. [PMID: 25603799 PMCID: PMC4321700 DOI: 10.1186/s12915-015-0114-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/09/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The nematode worm Caenorhabditis elegans, in which loss-of-function mutants and RNA interference (RNAi) models are available, is a model organism useful for analyzing effects of genes on various life phenomena, including behavior. In particular, RNAi is a powerful tool that enables time- or cell-specific knockdown via heat shock-inducible RNAi or cell-specific RNAi. However, conventional RNAi is insufficient for investigating pleiotropic genes with various sites of action and life stage-dependent functions. RESULTS Here, we investigated the Ras gene for its role in exploratory behavior in C. elegans. We found that, under poor environmental conditions, mutations in the Ras-MAPK signaling pathway lead to circular locomotion instead of normal exploratory foraging. Spontaneous foraging is regulated by a neural circuit composed of three classes of neurons: IL1, OLQ, and RMD, and we found that Ras functions in this neural circuit to modulate the direction of locomotion. We further observed that Ras plays an essential role in the regulation of GLR-1 glutamate receptor localization in RMD neurons. To investigate the temporal- and cell-specific profiles of the functions of Ras, we developed a new RNAi method that enables simultaneous time- and cell-specific knockdown. In this method, one RNA strand is expressed by a cell-specific promoter and the other by a heat shock promoter, resulting in only expression of double-stranded RNA in the target cell when heat shock is induced. This technique revealed that control of GLR-1 localization in RMD neurons requires Ras at the adult stage. Further, we demonstrated the application of this method to other genes. CONCLUSIONS We have established a new RNAi method that performs simultaneous time- and cell-specific knockdown and have applied this to reveal temporal profiles of the Ras-MAPK pathway in the control of exploratory behavior under poor environmental conditions.
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Affiliation(s)
- Masayuki Hamakawa
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Takayuki Uozumi
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Naoko Ueda
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Yuichi Iino
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Takaaki Hirotsu
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, 812-8581, Japan. .,Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan. .,Department of Biology, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan. .,Division of Applied Medical Sensing, Research and Development Center for Taste and Odor Sensing, Kyushu University, Fukuoka, 819-0395, Japan.
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Niida A, Niida R, Matsuda H, Motomura M, Uechi A. Analysis of the presence or absence of atrophy of the subgenual and subcallosal cingulate cortices using voxel-based morphometry on MRI is useful to select prescriptions for patients with depressive symptoms. Int J Gen Med 2014; 7:513-24. [PMID: 25506239 PMCID: PMC4259869 DOI: 10.2147/ijgm.s72736] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Objective We objectively evaluated the presence or absence of atrophy of the subgenual anterior cingulate cortex (sgACC) and the subcallosal anterior cingulate cortex (scACC), using new voxel-based morphometry (VBM) software employing Statistical Parametric Mapping software v8 and diffeomorphic anatomic registration through an exponentiated lie algebra. We prepared a database covering young-mature adulthood and investigated the clinical usefulness of the evaluation. Subjects and methods One hundred seven patients with major depressive disorder (MDD), 74 patients with bipolar disorder (BD), and 240 healthy control subjects underwent 1.5T magnetic resonance imaging scanning. Using new VBM software and databases covering young-mature adults and the elderly, target volumes of interest were set in the sgACC and scACC, four indicators (severity, extent, ratio, and whole-brain extent) were determined, and the presence or absence of atrophy of the sgACC and scACC was evaluated on the basis of the indicators. In addition, the relationships between the presence or absence of atrophy of the sgACC and scACC and performance of diagnosing MDD and BD and therapeutic drugs were investigated. Results It was clarified that the disease is likely to be MDD when atrophy is detected in the sgACC, and likely to be BD when no atrophy is detected in the sgACC but is detected in the scACC. Regarding the relationship with therapeutic drugs, it was clarified that, when atrophy is detected in both the sgACC and the scACC, concomitant administration of mood stabilizers and atypical antipsychotics acting as dopamine-system stabilizers is necessary in many cases. Conclusion VBM on magnetic resonance imaging enabled automatic analysis of atrophy in the sgACC and scACC, and findings obtained by this procedure are useful not only for differentiation of MDD and BD patients but also for selection of prescriptions.
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Affiliation(s)
- Akira Niida
- Department of Radiology, Nanbu Hospital, Itoman City, Okinawa, Japan
| | - Richi Niida
- Department of Psychiatry, Nanto Clinic, Urasoe City, Okinawa, Japan
| | - Hiroshi Matsuda
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Kodaira City, Tokyo, Japan
| | - Makoto Motomura
- Department of Human Sciences, University of the Ryukyus, Nakagami County, Okinawa, Japan
| | - Akihiko Uechi
- Cognitive Neuroscience Research Project, Kansai Gaidai University, Hirakata City, Osaka, Japan
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Sorting nexin 27 regulation of G protein-gated inwardly rectifying K⁺ channels attenuates in vivo cocaine response. Neuron 2014; 82:659-69. [PMID: 24811384 DOI: 10.1016/j.neuron.2014.03.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2014] [Indexed: 12/12/2022]
Abstract
The subcellular pathways that regulate G protein-gated inwardly rectifying potassium (GIRK or Kir3) channels are important for controlling the excitability of neurons. Sorting nexin 27 (SNX27) is a PDZ-containing protein known to bind GIRK2c/GIRK3 channels, but its function in vivo is poorly understood. Here, we investigated the role of SNX27 in regulating GIRK currents in dopamine (DA) neurons of the ventral tegmental area (VTA). Mice lacking SNX27 in DA neurons exhibited reduced GABABR-activated GIRK currents but had normal Ih currents and DA D2R-activated GIRK currents. Expression of GIRK2a, an SNX27-insensitive splice variant, restored GABABR-activated GIRK currents in SNX27-deficient DA neurons. Remarkably, mice with significantly reduced GABABR-activated GIRK currents in only DA neurons were hypersensitive to cocaine and could be restored to a normal locomotor response with GIRK2a expression. These results identify a pathway for regulating excitability of VTA DA neurons, highlighting SNX27 as a promising target for treating addiction.
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